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Sample records for gas monitoring chamber

  1. Automated soil gas monitoring chamber

    DOEpatents

    Edwards, Nelson T.; Riggs, Jeffery S.

    2003-07-29

    A chamber for trapping soil gases as they evolve from the soil without disturbance to the soil and to the natural microclimate within the chamber has been invented. The chamber opens between measurements and therefore does not alter the metabolic processes that influence soil gas efflux rates. A multiple chamber system provides for repetitive multi-point sampling, undisturbed metabolic soil processes between sampling, and an essentially airtight sampling chamber operating at ambient pressure.

  2. The Gas Monitoring of the Besiii Drift Chamber

    NASA Astrophysics Data System (ADS)

    Wang, Xianggao; Chen, Chang; Chen, Yuanbo; Wu, Zhi; Gu, Yunting; Ma, Xiaoyan; Jin, Yan; Liu, Rongguang; Tang, Xiao; Wang, Lan; Zhu, Qiming

    Two monitoring proportional counters (MPCs), installed at the inlet and outlet of the gas system of BESIII drift chamber (DC), were used to monitor the operation of the BESIII DC successfully and effectively as reported in this paper. The ratio of Gout/Gin (full energy photoelectron peak position of 55Fe 5.9 keV X-ray in inlet MPC as Gin and outlet MPC as Gout) is used as the main monitoring parameter. The MPC method is very useful for the gas detector system.

  3. Drift time spectrum and gas monitoring in the ATLAS Muon Spectrometer precision chambers

    NASA Astrophysics Data System (ADS)

    Levin, Daniel S.; Amram, Nir; Ball, Robert; ben Moshe, Meny; Benhammou, Yan; Chapman, John W.; Dai, Tiesheng; Diehl, Edward B.; Etzion, Erez; Ferretti, Claudio; Goldfarb, Steven; Gregory, Jeffery; Kiesel, Mike; McKee, Shawn; Thun, Rudi; Weaverdyck, Curtis; Wilson, Alan; Zhao, Zhengguo; Zhou, Bing

    2008-04-01

    The ATLAS Muon Spectrometer incorporates 354 000 drift tubes assembled into 1200 Monitored Drift Tube (MDT) precision chambers, with a total gas volume of 723 m3. This MDT gas, Ar 93% and CO2 7% at 3 bar, is cycled through the spectrometer at a rate of one total detector volume per day. Achieving the 80 μm drift tube design resolution requires stringent gas quality control as a fundamental component of the MDT calibration program. We report on the design, deployment and performance of a dedicated MDT mini-chamber conceived for continuous monitoring and drift time calibration of the ATLAS MDT operating gas. This chamber enables measurement of the drift spectra from which gas properties relevant to MDT calibrations and stable operating conditions are determined. Located in the ATLAS gas facility at CERN, the mini-chamber produces hourly drift spectra which are automatically analyzed. Results are published online and disseminated to the ATLAS muon system conditions and calibration databases in real time.

  4. Continuous monitoring of soil gas efflux with Forced Diffusion (FD) chamber technique in a tundra ecosystem, Alaska

    NASA Astrophysics Data System (ADS)

    Kim, Y.; Park, S. J.; Lee, B. Y.

    2015-12-01

    Continuous measurements of soil carbon dioxide (CO2) efflux provide essential information about the soil carbon budget in response to an abruptly changing climate at Arctic and Subarctic scales. The Forced Diffusion (FD) chamber technique has a gas permeable membrane, which passively regulates the mixing of atmosphere and soil air in the chamber, in place of the active pumping system inside a regular dynamics efflux chamber system (Risk et al., 2011). Here the system has been modified the sampling routine to eliminate the problem of sensor drift. After that, we deployed the FD chamber system in a tundra ecosystem over the discontinuous permafrost regime of Council, Alaska. The representative understory plants are tussock (17 %), lichen (32 %), and moss (51 %), within a 40 נ40 m plot at an interval of five meters (81 points total) for efflux-measurement by dynamic chamber. The FD chamber monitored soil CO2 efflux from moss, lichen, and tussock regimes at an interval of 30 min during the growing season of 2015. As the results, mean soil CO2 effluxes in sphagnum moss, lichen, and tussock were 1.98 ± 1.10 (coefficient of variance: 55.8 %), 3.34 ± 0.84 (CV: 25.0 %), and 5.32 ± 1.48 (CV: 27.8 %) gCO2/m2/d, respectively. The difference between the 30-min efflux interval and the average efflux of three 10-min intervals is not significant for sphagnum (n = 196), lichen (n = 918), and tussock (n = 918) under a 95 % confidence level. The deploying interval was then set to 30 min and synchronized with eddy covariance tower data. During the deployment period of 2015, soil CO2 efflux over moss, lichen, and tussock using the FD chamber system were 44 ± 24, 73 ± 18, and 117 ± 33 gCO2/m2/period, respectively. Using the dynamic chamber, mean ecosystem respiration (Re) ranges for moss, lichen, and tussock were 2.2-2.6, 1.8-2.0, and 3.3-3.6 gCO2/m2/d, respectively, during June and July of 2015. These techniques provide the representativeness of spatiotemporal variation of soil

  5. Automatic semi-continuous accumulation chamber for diffuse gas emissions monitoring in volcanic and non-volcanic areas

    NASA Astrophysics Data System (ADS)

    Lelli, Matteo; Raco, Brunella; Norelli, Francesco; Virgili, Giorgio; Continanza, Davide

    2016-04-01

    Since various decades the accumulation chamber method is intensively used in monitoring activities of diffuse gas emissions in volcanic areas. Although some improvements have been performed in terms of sensitivity and reproducibility of the detectors, the equipment used for measurement of gas emissions temporal variation usually requires expensive and bulky equipment. The unit described in this work is a low cost, easy to install-and-manage instrument that will make possible the creation of low-cost monitoring networks. The Non-Dispersive Infrared detector used has a concentration range of 0-5% CO2, but the substitution with other detector (range 0-5000 ppm) is possible and very easy. Power supply unit has a 12V, 7Ah battery, which is recharged by a 35W solar panel (equipped with charge regulator). The control unit contains a custom programmed CPU and the remote transmission is assured by a GPRS modem. The chamber is activated by DataLogger unit, using a linear actuator between the closed position (sampling) and closed position (idle). A probe for the measure of soil temperature, soil electrical conductivity, soil volumetric water content, air pressure and air temperature is assembled on the device, which is already arranged for the connection of others external sensors, including an automatic weather station. The automatic station has been tested on the field at Lipari island (Sicily, Italy) during a period of three months, performing CO2 flux measurement (and also weather parameters), each 1 hour. The possibility to measure in semi-continuous mode, and at the same time, the gas fluxes from soil and many external parameters, helps the time series analysis aimed to the identification of gas flux anomalies due to variations in deep system (e.g. onset of volcanic crises) from those triggered by external conditions.

  6. Proton beam monitor chamber calibration.

    PubMed

    Gomà, C; Lorentini, S; Meer, D; Safai, S

    2014-09-01

    The first goal of this paper is to clarify the reference conditions for the reference dosimetry of clinical proton beams. A clear distinction is made between proton beam delivery systems which should be calibrated with a spread-out Bragg peak field and those that should be calibrated with a (pseudo-)monoenergetic proton beam. For the latter, this paper also compares two independent dosimetry techniques to calibrate the beam monitor chambers: absolute dosimetry (of the number of protons exiting the nozzle) with a Faraday cup and reference dosimetry (i.e. determination of the absorbed dose to water under IAEA TRS-398 reference conditions) with an ionization chamber. To compare the two techniques, Monte Carlo simulations were performed to convert dose-to-water to proton fluence. A good agreement was found between the Faraday cup technique and the reference dosimetry with a plane-parallel ionization chamber. The differences-of the order of 3%-were found to be within the uncertainty of the comparison. For cylindrical ionization chambers, however, the agreement was only possible when positioning the effective point of measurement of the chamber at the reference measurement depth-i.e. not complying with IAEA TRS-398 recommendations. In conclusion, for cylindrical ionization chambers, IAEA TRS-398 reference conditions for monoenergetic proton beams led to a systematic error in the determination of the absorbed dose to water, especially relevant for low-energy proton beams. To overcome this problem, the effective point of measurement of cylindrical ionization chambers should be taken into account when positioning the reference point of the chamber. Within the current IAEA TRS-398 recommendations, it seems advisable to use plane-parallel ionization chambers-rather than cylindrical chambers-for the reference dosimetry of pseudo-monoenergetic proton beams. PMID:25109620

  7. EPA GAS PHASE CHEMISTRY CHAMBER STUDIES

    EPA Science Inventory

    Gas-phase smog chamber experiments are being performed at EPA in order to evaluate a number of current chemical mechanisms for inclusion in EPA regulatory and research models. The smog chambers are 9000 L in volume and constructed of 2-mil teflon film. One of the chambers is co...

  8. Gas turbine combustion chamber with air scoops

    SciTech Connect

    Mumford, S.E.; Smed, J.P.

    1989-12-19

    This patent describes a gas turbine combustion chamber. It comprises: means for admission of fuel to the upstream end thereof and discharge of hot gases from the downstream end thereof, and a combustion chamber wall, having an outer surface, with apertures therethrough, and air scoops provided through the apertures to direct air into the combustion chamber.

  9. Formaldehyde vapor produced from hexamethylenetetramine and pesticide: Simultaneous monitoring of formaldehyde and ozone in chamber experiments by flow-based hybrid micro-gas analyzer.

    PubMed

    Yanaga, Akira; Hozumi, Naruto; Ohira, Shin-Ichi; Hasegawa, Asako; Toda, Kei

    2016-02-01

    Simultaneous analysis of HCHO and O3 was performed by the developed flow analysis system to prove that HCHO vapor is produced from solid pesticide in the presence of O3. HCHO is produced in many ways, including as primary emissions from fuel combustion and in secondary production from anthropogenic and biogenic volatile organic compounds by photochemical reactions. In this work, HCHO production from pesticides was investigated for the first time. Commonly pesticide contains surfactant such as hexamethylenetetramine (HMT), which is a heterocyclic compound formed from six molecules of HCHO and four molecules of NH3. HMT can react with gaseous oxidants such as ozone (O3) to produce HCHO. In the present study, a flow analysis system was developed for simultaneous analysis of HCHO and O3, and this system was used to determine if solid pesticides produced HCHO vapor in the presence of O3. HMT or the pesticide jimandaisen, which contains mancozeb as the active ingradient and HMT as a stabilizer was placed at the bottom of a 20-L stainless steel chamber. Air in the chamber was monitored using the developed flow system. Analyte gases were collected into an absorbing solution by a honeycomb-patterned microchannel scrubber that was previously developed for a micro gas analysis system (μGAS). Subsequently, indigotrisulfonate, a blue dye, was added to the absorbing solution to detect O3, which discolored the solution. HCHO was detected after mixing with the Hantzsch reaction reagent. Both gases could be detected at concentrations ranging from parts per billion by volume (ppbv) to 1000 ppbv with good linearity. Both HMT and jimandaisen emitted large amount of HCHO in the presence of O3. PMID:26653496

  10. Experimental investigation, modeling, and simulations for MEMS-based gas sensor used for monitoring process chambers in semiconductor manufacturing

    NASA Astrophysics Data System (ADS)

    Jafri, Ijaz H.; DiMeo, Frank, Jr.; Neuner, Jeffrey W.; DiMascio, Sue; Marchetti, James

    2001-04-01

    There is a growing demand from the semiconductor industry for multi-component gas sensing for advanced process control applications. Microelectromechanical systems (MEMS) based integrated gas sensors present several advantages for this application such as ease of array fabrication, small size, and unique thermal manipulation capabilities. MEMS based gas sensors that are produced using a standard CMOS (Complimentary Metal Oxide Semiconductor) process have the additional advantages of being readily realized by commercial foundries and amenable to the inclusion of on-chip electronics. In order to speed the design and optimization of such integrated gas sensors, a commercial software package IntelliSuiteTM was used to model the coupled thermo-electro-mechanical responses of devices known as microhotplates. Models were built based on the GDSII formatted mask layout, process sequences, and layer thicknesses. During these simulations, key parameters such as device design and structure were investigated, as well as their effect on the resultant device temperature distribution and mechanical deflection. Detailed analyses were conducted to study the resonance modes for different sensor configurations, such as fixed-end and springboard arrangements. These analyses also included a study of the effect of absorbed material on device natural frequency. The modeling results from this study predict that the first three resonant frequency modes for these devices are in the 612 to 1530 kHz range for an all pinned device, and 134 to 676 kHz for a springboard arrangement. Furthermore, the modeling suggests that the resonant frequencies will decrease linearly as a function of increasing absorbed mass, as expected for a simple spring model. The change in resonant frequency due to mass absorption is higher for an all-pinned arrangement, compared to a springboard arrangement, with the second and third (twisting mode) showing the largest change. Thermo-electro-mechanical simulations were

  11. Comment on 'Proton beam monitor chamber calibration'.

    PubMed

    Palmans, Hugo; Vatnitsky, Stanislav M

    2016-09-01

    We comment on a recent article (Gomà et al 2014 Phys. Med. Biol. 59 4961-71) which compares different routes of reference dosimetry for the energy dependent beam monitor calibration in scanned proton beams. In this article, a 3% discrepancy is reported between a Faraday cup and a plane-parallel ionization chamber in the experimental determination of the number of protons per monitor unit. It is further claimed that similar discrepancies between calorimetry and ionization chamber based dosimetry indicate that [Formula: see text]-values tabulated for proton beams in IAEA TRS-398 might be overestimated. In this commentary we show, however, that this supporting argument misrepresents the evidence in the literature and that the results presented, together with published data, rather confirm that there exist unresolved problems with Faraday cup dosimetry. We also show that the comparison in terms of the number of protons gives a biased view on the uncertainty estimates for both detectors while the quantity of interest is absorbed dose to water or dose-area-product to water, even if a beam monitor is calibrated in terms of the number of protons. Gomà et al (2014 Phys. Med. Biol. 59 4961-71) also report on the discrepancy between cylindrical and plane-parallel ionization chambers and confirm experimentally that in the presence of a depth dose gradient, theoretical values of the effective point of measurement, or alternatively a gradient correction factor, account for the discrepancy. We believe this does not point to an error or shortcoming of IAEA TRS-398, which prescribes taking the centre of cylindrical ionization chambers as reference point, since it recommends reference dosimetry to be performed in the absence of a depth dose gradient. But these observations reveal that important aspects of beam monitor calibration in scanned proton beams are not addressed in IAEA TRS-398 given that those types of beams were not widely implemented at the time of its publication

  12. Gas Electron Multiplier (GEM) Chamber Characteristics Test

    SciTech Connect

    Yu, Jaehoon; White, Andy; Park, Seongtae; Hahn, Changhie; Baldeloma, Edwin; Tran, Nam; McIntire, Austin; Soha, Aria; /Fermilab

    2011-01-11

    Gas Electron Multipliers (GEMs) have been used in many HEP experiments as tracking detectors. They are sensitive to X-rays which allows use beyond that of HEP. The UTA High Energy group has been working on using GEMs as the sensitive gap detector in a DHCAL for the ILC. The physics goals at the ILC put a stringent requirement on detector performance. Especially the precision required for jet mass and positions demands an unprecedented jet energy resolution to hadronic calorimeters. A solution to meet this requirement is using the Particle Flow Algorithm (PFA). In order for PFA to work well, high calorimeter granularity is necessary. Previous studies based on GEANT simulations using GEM DHCAL gave confidence on the performance of GEM in the sensitive gap in a sampling calorimeter and its use as a DHCAL in PFA. The UTA HEP team has built several GEM prototype chambers, including the current 30cm x 30cm chamber integrated with the SLAC-developed 64 channel kPiX analog readout chip. This chamber has been tested on the bench using radioactive sources and cosmic ray muons. In order to have fuller understanding of various chamber characteristics, the experiments plan to expose 1-3 GEM chambers of dimension 35cm x 35cm x 5cm with 1cm x 1cm pad granularity with 64 channel 2-D simultaneous readout using the kPiX chip. In this experiment the experiments pan to measure MiP signal height, chamber absolute efficiencies, chamber gain versus high voltage across the GEM gap, the uniformity of the chamber across the 8cm x 8cm area, cross talk and its distance dependence to the triggered pad, chamber rate capabilities, and the maximum pad occupancy rate.

  13. Carbon copy deaths: carbon monoxide gas chamber.

    PubMed

    Patel, F

    2008-08-01

    The news media can exert a powerful influence over suicidal behaviour. It has been observed that like-minded individuals are able to preplan a group suicide method using modern communication technology in the form of websites and online chatrooms and mobile phone texting. A case of carbon monoxide (CO) poisoning is presented to illustrate the recent phenomenon of cyber suicides by suffocation from a burning barbecue (charcoal burner) in 'gas chamber' conversions. Although barbecues (BBQ) are very popular in Britain and widely available, there have been relatively few reported cases of copycat deaths from CO gas suffocation. PMID:18586213

  14. A new ring-shaped graphite monitor ionization chamber

    NASA Astrophysics Data System (ADS)

    Yoshizumi, M. T.; Caldas, L. V. E.

    2010-07-01

    A ring-shaped monitor ionization chamber was developed at the Instituto de Pesquisas Energéticas e Nucleares. This ionization chamber presents an entrance window of aluminized polyester foil. The guard ring and collecting electrode are made of graphite coated Lucite plates. The main difference between this new ionization chamber and commercial monitor chambers is its ring-shaped design. The new monitor chamber has a central hole, allowing the passage of the direct radiation beam without attenuation; only the penumbra radiation is measured by the sensitive volume. This kind of ionization chamber design has already been tested, but using aluminium electrodes. By changing the electrode material from aluminium to a graphite coating, an improvement in the chamber response stability was expected. The pre-operational tests, as saturation curve, recombination loss and polarity effect showed satisfactory results. The repeatability and the long-term stability tests were also evaluated, showing good agreement with international recommendations.

  15. Quartz crystals detect gas contaminants during vacuum chamber evacuation

    NASA Technical Reports Server (NTRS)

    Stephens, J. B.

    1967-01-01

    Piezoelectric quartz crystals detect condensable gas contaminants backstreaming into a vacuum chamber when a pump is evacuating the chamber. One crystal acts as a thermometer, the other detects mass change. They are energized by electronic equipment which records frequency changes.

  16. RADIATION MONITOR CONTAINING TWO CONCENTRIC IONIZATION CHAMBERS AND MEANS FOR INSULATING THE SEPARATE CHAMBERS

    DOEpatents

    Braestrup, C.B.; Mooney, R.T.

    1964-01-21

    This invention relates to a portable radiation monitor containing two concentric ionization chambers which permit the use of standard charging and reading devices. It is particularly adapted as a personnel x-ray dosimeter and to this end comprises a small thin walled, cylindrical conductor forming an inner energy dependent chamber, a small thin walled, cylindrical conductor forming an outer energy independent chamber, and polymeric insulation means which insulates said chambers from each other and holds the chambers together with exposed connections in a simple, trouble-free, and compact assembly substantially without variation in directional response. (AEC)

  17. Gas exchange in NASA's biomass production chamber - A preprototype closed human life support system

    NASA Technical Reports Server (NTRS)

    Corey, Kenneth A.; Wheeler, Raymond M.

    1992-01-01

    The unique capabilities of the NASA biomass production chamber for monitoring and evaluating gas exchange rates are examined. Special emphasis is given to results with wheat and soybeans. The potential of the chamber as a preprototype of a closed human life support system is considered.

  18. 30 CFR 77.305 - Access to drying chambers, hot gas inlet chambers and ductwork; installation and maintenance.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Access to drying chambers, hot gas inlet chambers and ductwork; installation and maintenance. 77.305 Section 77.305 Mineral Resources MINE SAFETY... drying chambers, hot gas inlet chambers and ductwork; installation and maintenance. Drying chambers,...

  19. 30 CFR 77.305 - Access to drying chambers, hot gas inlet chambers and ductwork; installation and maintenance.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 30 Mineral Resources 1 2012-07-01 2012-07-01 false Access to drying chambers, hot gas inlet chambers and ductwork; installation and maintenance. 77.305 Section 77.305 Mineral Resources MINE SAFETY... drying chambers, hot gas inlet chambers and ductwork; installation and maintenance. Drying chambers,...

  20. 30 CFR 77.305 - Access to drying chambers, hot gas inlet chambers and ductwork; installation and maintenance.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Access to drying chambers, hot gas inlet chambers and ductwork; installation and maintenance. 77.305 Section 77.305 Mineral Resources MINE SAFETY... drying chambers, hot gas inlet chambers and ductwork; installation and maintenance. Drying chambers,...

  1. 30 CFR 77.305 - Access to drying chambers, hot gas inlet chambers and ductwork; installation and maintenance.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Access to drying chambers, hot gas inlet chambers and ductwork; installation and maintenance. 77.305 Section 77.305 Mineral Resources MINE SAFETY... drying chambers, hot gas inlet chambers and ductwork; installation and maintenance. Drying chambers,...

  2. 30 CFR 77.305 - Access to drying chambers, hot gas inlet chambers and ductwork; installation and maintenance.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 30 Mineral Resources 1 2013-07-01 2013-07-01 false Access to drying chambers, hot gas inlet chambers and ductwork; installation and maintenance. 77.305 Section 77.305 Mineral Resources MINE SAFETY... drying chambers, hot gas inlet chambers and ductwork; installation and maintenance. Drying chambers,...

  3. 108. Cylindrical chamber where gas exits stove to below ground ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    108. Cylindrical chamber where gas exits stove to below ground flue that leads to stack. - Sloss-Sheffield Steel & Iron, First Avenue North Viaduct at Thirty-second Street, Birmingham, Jefferson County, AL

  4. Ionization chamber for measurements of high-level tritium gas

    SciTech Connect

    Carstens, D.H.W.; David, W.R.

    1980-01-01

    The construction and calibration of a simple ionization-chamber apparatus for measurement of high level tritium gas is described. The apparatus uses an easily constructed but rugged chamber containing the unknown gas and an inexpensive digital multimeter for measuring the ion current. The equipment after calibration is suitable for measuring 0.01 to 100% tritium gas in hydrogen-helium mixes with an accuracy of a few percent. At both the high and low limits of measurements deviations from the predicted theoretical current are observed. These are briefly discussed.

  5. Microstrip Gas Chambers on glass and ceramic substrates

    SciTech Connect

    Gong, W.G.; Wieman, H.; Harris, J.W.; Mitchell, J.T.; Hong, W.S.; Perez-Mendez, V.

    1993-11-01

    We report developments of Microstrip Gas Chambers (MSGC) fabricated on glass and ceramic substrates with various resistivities. Low resistivity of the substrate is found to be critical for achieving stable operation of microstrip gas chambers. The microstrip pattern consists of 10 {mu}m wide anodes and 90 {mu}m wide cathodes with a 200 {mu}m anode-to-anode pitch. High-quality microstrips are fabricated using the dry etch after UV-photolithography. Our chambers are tested in an Ar(90)-CH{sub 4}(10) gas mixture at atmospheric pressure with a 100 {mu}Ci {sup 55}Fe source. An energy resolution (FWHM) of 15% has been achieved for 6 keV soft X-rays. At a rate of 5 {times} 10{sup 4} photons/sec/mm{sup 2}, gas gains are stable within a few percents. Long-term tests of gain stability and rate capability are yet to be pursued.

  6. Field Evaluation of Open System Chambers for Measuring Whole Canopy Gas Exchanges

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The ability to monitor whole canopy CO2 and H2O fluxes of crop plants in the field is needed for many research efforts ranging from plant breeding to the study of Climate Change effects on crops. Four portable, transparent, open system chambers for measuring canopy gas exchanges were field tested on...

  7. Data Quality Monitoring for the CMS Resistive Plate Chamber Detector

    NASA Astrophysics Data System (ADS)

    Cimmino, A.; CMS Collaboration

    2011-06-01

    Resistive Plate Chambers (RPCs), with their excellent time resolution (˜ 2 ns), were chosen as dedicated muon trigger detectors for the CMS experiment. RPCs fulfill the job of muon identification, estimate the momentum and unambiguously assign bunch crossing. The critical tasks of monitoring detector performances, debugging hardware, and certifying recorded data are carried out by the RPC Data Quality Monitoring (DQM) system. We here describe the structure, functionalities, and performances of the DQM applications for the CMS RPC detector.

  8. Thin gap gas chambers for the DELPHI endcaps

    SciTech Connect

    Adam, W.; Hrubec, J.

    1996-12-31

    Thin Gap Gas Chambers have been proposed for an upgrade of the endcaps of the DELPHI detector at LEP. Two full size chambers have been built and a study of the optimal operating conditions has been carried out. In this paper the main construction parameters are discussed and test results will be given. Tests of the electronic readout were performed and the general feasibility of the detector is demonstrated.

  9. Gas and aerosol wall losses in Teflon film smog chambers

    SciTech Connect

    McMurry, P.H.; Grosjean, D.

    1985-12-01

    Large smog chambers (approx.60 m/sup 3/) constructed of FEP Teflon film are frequently used to study photochemistry and aerosol formation in model chemical systems. In a previous paper a theory for aerosol wall loss rates in Teflon film smog chambers was developed; predicted particle loss rates were in good agreement with measured rates. In the present paper, measurements of wall deposition rates and the effects of wall losses on measurements of gas-to-particle conversion in smog chambers are discussed. Calculations indicate that a large fraction of the aerosol formed in several smog chamber experiments was on the chamber walls at the end of the experiment. Estimated values for particulate organic carbon yield for several precursor hydrocarbons increased by factors of 1.3-6.0 when wall deposition was taken into account. The theory is also extended to loss rates of gaseous species. Such loss rates are either limited by diffusion through a concentration boundary layer near the surface or by uptake at the surface. It is shown that for a typical 60-m/sup 3/ Teflon film smog chamber, gas loss rates are limited by surface reaction rates if mass accommodation coefficients are less than 6 x 10/sup -6/. It follows that previously reported loss rates of several gases in a chamber of this type were limited by surface reactions.

  10. An inexpensive dual-chamber particle monitor: laboratory characterization

    SciTech Connect

    Rufus Edwards; Kirk R. Smith; Brent Kirby; Tracy Allen; Charles D. Litton; Susanne Hering

    2006-06-15

    In developing countries, high levels of particle pollution from the use of coal and biomass fuels for household cooking and heating are a major cause of ill health and premature mortality. Existing monitoring equipment makes routine quantification of household particle pollution levels difficult. Recent advances have enabled the development of a small, portable, data-logging particle monitor modified from commercial smoke alarm technology that can meet the needs of surveys in the developing world at reasonable cost. Laboratory comparisons of a prototype particle monitor developed at the University of California at Berkeley (UCB) with gravimetric filters, a tapered element oscillating microbalance, and a TSI DustTrak to quantify the UCB particle monitor response as a function of both concentration and particle size and to examine sensor response in relation to changes in temperature, relative humidity, and elevation are presented. UCB particle monitors showed good linearity in response to different concentrations of laboratory-generated oleic acid aerosols with a coarse and fine size distributions. The photoelectric and ionization chamber showed a wide range of responses based on particle size and, thus, require calibration with the aerosol of interest. The ionization chamber was five times more sensitive to fine rather than coarse particles, whereas the photoelectric chamber was five times more sensitive to coarse than fine. The ratio of the response between the two sensors has the potential for mass calibration of individual data points based on estimated parameters of the size distribution. The results demonstrate the significant potential of this monitor, which will facilitate the evaluation of interventions (improved fuels, stoves, and ventilation) on indoor air pollution levels and research on the impacts of indoor particle levels on health in developing countries. 10 refs., 10 figs., 2 tabs.

  11. Anterior chamber gas bubbles in open globe injury.

    PubMed

    Barnard, E B G; Baxter, D; Blanch, R

    2013-01-01

    We present a case of a 40-year-old soldier who was in close proximity to the detonation of an improvised explosive device (IED). Bubbles of gas were visible within the anterior chamber of his left eye. The authors propose that intraocular gas, present acutely after trauma, is diagnostic of open globe injury and is of particular importance in remote military environments. PMID:24079202

  12. Fundamental study on gas monitoring in celss

    NASA Astrophysics Data System (ADS)

    Nishi, I.; Tateishi, T.; Tomizawa, G.; Nitta, K.; Oguchi, M.

    A mass spectrometer and computer system was developed for conducting a fundamental study on gas monitoring in CELSS. Respiration and metabolism of the hamster and photosynthesis of the Spirulina were measured in a combination system consisting of a hamster chamber and a Spirulina cultivator. They are connected through a membrane gas exchanger. Some technical problems were examined. In the mass spectrometric gas monitoring, a simultaneous multi-sample measurement was developed by employing a rotating exchange valve. Long term precise measurement was obtained by employing an automatic calibration system. The membrane gas sampling probe proved to be useful for long term measurement. The cultivation rate of the Spirulina was effectively changed by controlling CO2 and light supply. The experimental results are helpful for improving the hamster-spirulina system.

  13. Fundamental study on gas monitoring in CELSS

    NASA Technical Reports Server (NTRS)

    Nishi, I.; Tateishi, T.; Tomizawa, G.; Nitta, K.; Oguchi, M.

    1987-01-01

    A mass spectrometer and computer system was developed for conducting a fundamental study on gas monitoring in a Controlled Ecological Life Support System. Respiration and metabolism of the hamster and photosynthesis of the Spirulina were measured in a combination system consisting of a hamster chamber and a Spirulina cultivator. They are connected through a membrane gas exchanger. Some technical problems were examined. In the mass spectrometric gas monitoring, a simultaneous multisample measurement was developed by employing a rotating exchange valve. Long term precise measurement was obtained by employing an automatic calibration system. The membrane gas sampling probe proved to be useful for long term measurement. The cultivation rate of the Spirulina was effectively changed by controlling CO2 and light supply. The experimental results are helpful for improving the hamster-spirulina system.

  14. Characterization of Gas Transport Properties of Fractured Rocks By Borehole and Chamber Tests.

    NASA Astrophysics Data System (ADS)

    Shimo, M.; Shimaya, S.; Maejima, T.

    2014-12-01

    Gas transport characteristics of fractured rocks is a great concern to variety of engineering applications such as underground storage of LPG, nuclear waste disposal, CCS and gas flooding in the oil field. Besides absolute permeability, relative permeability and capillary pressure as a function of water saturation have direct influences to the results of two phase flow simulation. However, number of the reported gas flow tests for fractured rocks are limited, therefore, the applicability of the conventional two-phase flow functions used for porous media, such as Mualem-van Genuchten model, to prediction of the gas transport in the fractured rock mass are not well understood. The authors conducted the two types of in-situ tests, with different scales, a borehole gas-injection test and a chamber gas-injection test in fractured granitic rock. These tests were conducted in the Cretaceous granitic rocks at the Namikata underground LPG storage cavern construction site in Ehime Prefecture in Japan, preceding to the cavern scale gas-tightness test. A borehole injection test was conducted using vertical and sub-vertical boreholes drilled from the water injection tunnel nearly at the depth of the top of the cavern, EL-150m. A new type downhole gas injection equipment that is capable to create a small 'cavern' within a borehole was developed. After performing a series of preliminary tests to investigate the hydraulic conductivity and gas-tightness, i.e. threshold pressure, gas injection tests were conducted under different gas pressure. Fig.1 shows an example of the test results From a chamber test using a air pressurizing chamber with volume of approximately166m3, the gas-tightness was confirmed within the uncertainty of 22Pa under the storage pressure of 0.7MPa, however, significant air leakage occurred possibly through an open fracture intersecting the chamber just after cavern pressure exceeds the initial hydrostatic pressure at the ceiling level of the chamber. Anomalies

  15. Using sputter coated glass to stabilize microstrip gas chambers

    DOEpatents

    Gong, Wen G.

    1997-01-01

    By sputter coating a thin-layer of low-resistive, electronically-conductive glass on various substrates (including quartz and ceramics, thin-film Pestov glass), microstrip gas chambers (MSGC) of high gain stability, low leakage current, and a high rate capability can be fabricated. This design can make the choice of substrate less important, save the cost of ion-implantation, and use less glass material.

  16. An ionization chamber shower detector for the LHC Luminosity Monitor

    SciTech Connect

    Speziali, V.; Beche, J.F.; Burks, M.T.; Datte, P.S.; Haguenauer, M.; manfredi, P.F.; Millaud, J.E.; Placidi, M.; Ratti, L.; Re, V.; Riot, V.J.; Schmickler, H.; Turner, W.C.

    2000-10-01

    The front IR quadrupole absorbers (TAS) and the IR neutral particle absorbers (TAN) in the high luminosity insertions of the Large Hadron Collider (LHC) each absorb approximately 1.8 TeV of forward collision products on average per pp interaction (~;;235W at design luminosity 1034cm-2s-1). This secondary particle flux can be exploited to provide a useful storage ring operations tool for optimization of luminosity. A novel segmented, multi-gap, pressurized gas ionization chamber is being developed for sampling the energy deposited near the maxima of the hadronic/ electromagnetic showers in these absorbers. The system design choices have been strongly influenced by optimization of signal to noise ratio and by the very high radiation environment. The ionization chambers are instrumented with low noise, fast, pulse shaping electronics to be capable of resolving individual bunch crossings at 40 MHz. Data on each bunch are to be separately accumulated over multiple bunch crossings until the desired statistical accuracy is obtained. At design luminosity approximately 2x103 bunch crossings will suffice for a 1percent luminosity measurement. In this paper we report the first experimental results of the ionization chamber and analog electronics. Single 450GeV protons from the SPS at CERN are used to simulate the hadronic/electromagnetic showers produced by the forward collision products from the interaction regions of the LHC.

  17. Monitoring Welding-Gas Quality

    NASA Technical Reports Server (NTRS)

    Huddleston, Kevin L.

    1988-01-01

    System monitors welding gas to ensure characteristics within predetermined values. Responds to changes that might go unnoticed by human operator and acts quickly to prevent weld defects. Electronic pressure controller employs various amounts of gain, equalization, and compensation to respond to changes in gas-supply pressure. Works in conjuction with pressure/oxygen/moisture monitor.

  18. 30 CFR 77.303 - Hot gas inlet chamber dropout doors.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Hot gas inlet chamber dropout doors. 77.303... COAL MINES Thermal Dryers § 77.303 Hot gas inlet chamber dropout doors. Thermal dryer systems which employ a hot gas inlet chamber shall be equipped with drop-out doors at the bottom of the inlet...

  19. 30 CFR 77.303 - Hot gas inlet chamber dropout doors.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 30 Mineral Resources 1 2013-07-01 2013-07-01 false Hot gas inlet chamber dropout doors. 77.303... COAL MINES Thermal Dryers § 77.303 Hot gas inlet chamber dropout doors. Thermal dryer systems which employ a hot gas inlet chamber shall be equipped with drop-out doors at the bottom of the inlet...

  20. 30 CFR 77.303 - Hot gas inlet chamber dropout doors.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 30 Mineral Resources 1 2012-07-01 2012-07-01 false Hot gas inlet chamber dropout doors. 77.303... COAL MINES Thermal Dryers § 77.303 Hot gas inlet chamber dropout doors. Thermal dryer systems which employ a hot gas inlet chamber shall be equipped with drop-out doors at the bottom of the inlet...

  1. 30 CFR 77.303 - Hot gas inlet chamber dropout doors.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Hot gas inlet chamber dropout doors. 77.303... COAL MINES Thermal Dryers § 77.303 Hot gas inlet chamber dropout doors. Thermal dryer systems which employ a hot gas inlet chamber shall be equipped with drop-out doors at the bottom of the inlet...

  2. 30 CFR 77.303 - Hot gas inlet chamber dropout doors.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Hot gas inlet chamber dropout doors. 77.303... COAL MINES Thermal Dryers § 77.303 Hot gas inlet chamber dropout doors. Thermal dryer systems which employ a hot gas inlet chamber shall be equipped with drop-out doors at the bottom of the inlet...

  3. Improvements in NDIR gas detection within the same optical chamber

    NASA Astrophysics Data System (ADS)

    Martinez-Anton, Juan Carlos; Silva-Lopez, Manuel

    2011-10-01

    Non-dispersive infrared (NDIR) is a well known technique for gas concentration monitoring. Lead salt photoconductors and thermopile detectors are typically used. Together with gas filter correlation (GFC) they are the basis for a reference standard in environmental gas monitoring like carbon monoxide determination and other gas species. To increase gas sensitivity, a multi-pass optical cavity is often used. In this contribution we propose a new optical design that allows for auto-reference multiple gas detection. It basically consists of an array of White's cell multi-pass camera that allows multiple channels with independent lengths inside the same volume. We explore its performance for carbon monoxide detection and based on recent commercial developments in infrared detector and emitter technologies.

  4. Slag monitoring system for combustion chambers of steam boilers

    SciTech Connect

    Taler, J.; Taler, D.

    2009-07-01

    The computer-based boiler performance system presented in this article has been developed to provide a direct and quantitative assessment of furnace and convective surface cleanliness. Temperature, pressure, and flow measurements and gas analysis data are used to perform heat transfer analysis in the boiler furnace and evaporator. Power boiler efficiency is calculated using an indirect method. The on-line calculation of the exit flue gas temperature in a combustion chamber allows for an on-line heat flow rate determination, which is transferred to the boiler evaporator. Based on the energy balance for the boiler evaporator, the superheated steam mass flow rate is calculated taking into the account water flow rate in attemperators. Comparing the calculated and the measured superheated steam mass flow rate, the effectiveness of the combustion chamber water walls is determined in an on-line mode. Soot-blower sequencing can be optimized based on actual cleaning requirements rather than on fixed time cycles contributing to lowering of the medium usage in soot blowers and increasing of the water-wall lifetime.

  5. Development of a portable gas-filled ionization chamber

    NASA Astrophysics Data System (ADS)

    Chae, K. Y.; Cha, S. M.; Gwak, M. S.

    2014-02-01

    A new portable gas-filled ionization chamber has been designed and constructed at the Physics Department of Sung Kyun Kwan University. To overcome the maximum count rate of ˜105 particles per second of a conventional ionization chamber, which utilizes a Frisch grid, and to enhance the portability of a detector, we adopted the design of multiple electrodes and modified it from the original designs by Kimura et al. and Chae et al. The new design utilizes a stack of multiple electrodes installed perpendicular to the optical beam axis. This configuration provides a fast response time for the detector, which is essential for high-rate counting. The device has been tested with a 241Am ( t 1/2 = 432.2 years) radioactive α source, which mainly emits 5.486-MeV (branching ratio of 85%) and 5.443-MeV (branching ratio of 13%) α particles. An energy resolution of 6.3% was achieved.

  6. Ion-chamber-based loss monitor system for the Los Alamos Meson Physics Facility

    SciTech Connect

    Plum, M.A.; Brown, D.; Browman, A.; Macek, R.J.

    1995-05-01

    A new loss monitor system has been designed and installed at the Los Alamos Meson Physics Facility (LAMPF). The detectors are ion chambers filled with N{sub 2} gas. The electronics modules have a threshold range of 1:100, and they can resolve changes in beam loss of about 2% of the threshold settings. They can generate a trip signal in 2 {mu}s if the beam loss is large enough; if the response time of the Fast Protect System is included the beam will be shut off in about 37 {mu}s.

  7. Oxygen sensor for monitoring gas mixtures containing hydrocarbons

    DOEpatents

    Ruka, Roswell J.; Basel, Richard A.

    1996-01-01

    A gas sensor measures O.sub.2 content of a reformable monitored gas containing hydrocarbons H.sub.2 O and/or CO.sub.2, preferably in association with an electrochemical power generation system. The gas sensor has a housing communicating with the monitored gas environment and carries the monitored gas through an integral catalytic hydrocarbon reforming chamber containing a reforming catalyst, and over a solid electrolyte electrochemical cell used for sensing purposes. The electrochemical cell includes a solid electrolyte between a sensor electrode that is exposed to the monitored gas, and a reference electrode that is isolated in the housing from the monitored gas and is exposed to a reference gas environment. A heating element is also provided in heat transfer communication with the gas sensor. A circuit that can include controls operable to adjust operations via valves or the like is connected between the sensor electrode and the reference electrode to process the electrical signal developed by the electrochemical cell. The electrical signal varies as a measure of the equilibrium oxygen partial pressure of the monitored gas. Signal noise is effectively reduced by maintaining a constant temperature in the area of the electrochemical cell and providing a monitored gas at chemical equilibria when contacting the electrochemical cell. The output gas from the electrochemical cell of the sensor is fed back into the conduits of the power generating system.

  8. Oxygen sensor for monitoring gas mixtures containing hydrocarbons

    DOEpatents

    Ruka, R.J.; Basel, R.A.

    1996-03-12

    A gas sensor measures O{sub 2} content of a reformable monitored gas containing hydrocarbons, H{sub 2}O and/or CO{sub 2}, preferably in association with an electrochemical power generation system. The gas sensor has a housing communicating with the monitored gas environment and carries the monitored gas through an integral catalytic hydrocarbon reforming chamber containing a reforming catalyst, and over a solid electrolyte electrochemical cell used for sensing purposes. The electrochemical cell includes a solid electrolyte between a sensor electrode that is exposed to the monitored gas, and a reference electrode that is isolated in the housing from the monitored gas and is exposed to a reference gas environment. A heating element is also provided in heat transfer communication with the gas sensor. A circuit that can include controls operable to adjust operations via valves or the like is connected between the sensor electrode and the reference electrode to process the electrical signal developed by the electrochemical cell. The electrical signal varies as a measure of the equilibrium oxygen partial pressure of the monitored gas. Signal noise is effectively reduced by maintaining a constant temperature in the area of the electrochemical cell and providing a monitored gas at chemical equilibria when contacting the electrochemical cell. The output gas from the electrochemical cell of the sensor is fed back into the conduits of the power generating system. 4 figs.

  9. Drift-Chamber Gas System Controls Development for the CEBAF Large Acceptance Spectrometer

    SciTech Connect

    M. F. Vineyard; T. J. Carroll; M. N. Lack

    1996-07-01

    The CEBAF Large Acceptance Spectrometer (CLAS) is a superconducting toroidal magnet with a large volume of drift chambers for charged particle tracking. The performance of these chambers depends on accurate monitoring and control of the mixture, flow rate, pressure, temperature, and contaminant levels of the gas. To meet these requirements, a control system is being developed with EPICS. The interface hardware consists of VME ADCs and three RS-232 low-level hardware controllers. The RS-232 instruments include MKS 647A mass flow controllers to control and monitor the gas mixture and flow, MKS 146B pressure gauge controllers to measure pressures, and a Panametrics hygrometer to monitor temperatures and the concentrations of oxygen, water vapor, and ethane. Many of the parameters are available as analog signals which will be monitored with XYCOM VME analog input cards and configured for alarms and data logging. The RS-232 interfaces will be used for remote control of the hardware and verification of the analog readings. Information will be passed quickly and efficiently to and from the user through a graphical user interface. A discussion of the requirements and design of the system is presented.

  10. Gas House Autonomous System Monitoring

    NASA Technical Reports Server (NTRS)

    Miller, Luke; Edsall, Ashley

    2015-01-01

    Gas House Autonomous System Monitoring (GHASM) will employ Integrated System Health Monitoring (ISHM) of cryogenic fluids in the High Pressure Gas Facility at Stennis Space Center. The preliminary focus of development incorporates the passive monitoring and eventual commanding of the Nitrogen System. ISHM offers generic system awareness, adept at using concepts rather than specific error cases. As an enabler for autonomy, ISHM provides capabilities inclusive of anomaly detection, diagnosis, and abnormality prediction. Advancing ISHM and Autonomous Operation functional capabilities enhances quality of data, optimizes safety, improves cost effectiveness, and has direct benefits to a wide spectrum of aerospace applications.

  11. Trace Gas Monitoring

    NASA Technical Reports Server (NTRS)

    1976-01-01

    Space technology is contributing to air pollution control primarily through improved detectors and analysis methods. Miniaturized mass spectrometer is under development to monitor vinyl chloride and other hydrocarbon contaminants in an airborne laboratory. Miniaturized mass spectrometer can be used to protect personnel in naval and medical operations as well as aboard aircraft.

  12. Ionisation Chambers and Secondary Emission Monitors at the PROSCAN Beam Lines

    SciTech Connect

    Doelling, Rudolf

    2006-11-20

    PROSCAN, the dedicated new medical facility at PSI using proton beams for the treatment of deep seated tumours and eye melanoma, is now in the commissioning phase. Air filled ionisation chambers in several configurations are used as current monitors, profile monitors, halo, position and loss monitors at the PROSCAN beam lines. Similar monitors based on secondary emission are used for profile and current measurements in the regime where saturation deteriorates the accuracy of the ionisation chambers.

  13. Pressure pulsations in combustion chambers of large gas turbines

    SciTech Connect

    Verhage, A.J.L.; Stevens, P.M.P.

    1998-07-01

    Flame instabilities and pressure pulsations have been measured in three different types of gas turbine combustors. These are the single and twin silo (such as the ABB GT13E and the Siemens V94.2), the annular combustion chamber (ABB GT 13E2, Siemens V84.3A, etc), and the multi-can combustors common on GEC-EGT gas turbines. Pressure pulsations are mostly resonant. They are interpreted with help of an acoustical model. Non-resonant modes at low frequencies (flame flicker) are ascribed to imperfect mixing especially in premix burners. At higher frequencies they are often due to vortices from the burners. Modifications of the burners, changes in the geometry of the liners and the addition of acoustical dampers are means to abate flame instabilities and the associated resonances. Judicious ways to run the gas turbine can help to avoid them. The efficiency of acoustical dampers of the Helmholtz type has been investigated experimentally and with model predictions.

  14. Gas mixture studies for streamer operated Resistive Plate Chambers

    NASA Astrophysics Data System (ADS)

    Paoloni, A.; Longhin, A.; Mengucci, A.; Pupilli, F.; Ventura, M.

    2016-06-01

    Resistive Plate Chambers operated in streamer mode are interesting detectors in neutrino and astro-particle physics applications (like OPERA and ARGO experiments). Such experiments are typically characterized by large area apparatuses with no stringent requirements on detector aging and rate capabilities. In this paper, results of cosmic ray tests performed on a RPC prototype using different gas mixtures are presented, the principal aim being the optimization of the TetraFluoroPropene concentration in Argon-based mixtures. The introduction of TetraFluoroPropene, besides its low Global Warming Power, is helpful because it simplifies safety requirements allowing to remove also isobutane from the mixture. Results obtained with mixtures containing SF6, CF4, CO2, N2 and He are also shown, presented both in terms of detectors properties (efficiency, multiple-streamer probability and time resolution) and in terms of streamer characteristics.

  15. Development of a Liquefied Noble Gas Time Projection Chamber

    NASA Astrophysics Data System (ADS)

    Lesser, Ezra; White, Aaron; Aidala, Christine

    2015-10-01

    Liquefied noble gas detectors have been used for various applications in recent years for detecting neutrinos, neutrons, photons, and potentially dark matter. The University of Michigan is developing a detector with liquid argon to produce scintillation light and ionization electrons. Our data collection method will allow high-resolution energy measurement and spatial reconstruction of detected particles by using multi-pixel silicon photomultipliers (SiPM) and a cylindrical time projection chamber (TPC) with a multi-wire endplate. We have already designed a liquid argon condenser and purification unit surrounded by an insulating vacuum, constructed circuitry for temperature and pressure sensors, and created software to obtain high-accuracy sensor readouts. The status of detector development will be presented. Funded through the Michigan Memorial Phoenix Project.

  16. Quantifying biases in non-steady state chamber measurements of soil-atmosphere gas exchange

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Limitations of non-steady state (NSS) chamber methods for determining soil-to-atmosphere trace gas exchange rates have been recognized for several decades. Of these limitations, the so-called “chamber effect” is one of the most challenging to overcome. The chamber effect can be defined as the inhere...

  17. Calculating the detection limits of chamber-based soil greenhouse gas flux measurements

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Renewed interest in quantifying greenhouse gas emissions from soil has lead to an increase in the application of chamber-based flux measurement techniques. Despite the apparent conceptual simplicity of chamber-based methods, nuances in chamber design, deployment, and data analyses can have marked ef...

  18. Improved Back-Side Purge-Gas Chambers For Plasma Arc Welding

    NASA Technical Reports Server (NTRS)

    Ezell, Kenneth G.; Mcgee, William F.; Rybicki, Daniel J.

    1995-01-01

    Improved chambers for inert-gas purging of back sides of workpieces during plasma arc welding in keyhole (full-penetration) mode based on concept of directing flows of inert gases toward, and concentrating them on, hot weld zones. Tapered chamber concentrates flow of inert gas on plasma arc plume and surrounding metal.

  19. Calculating the detection limits of chamber-based greenhouse gas flux measurements

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Chamber-based measurement of greenhouse gas emissions from soil is a common technique. However, when changes in chamber headspace gas concentrations are small over time, determination of the flux can be problematic. Several factors contribute to the reliability of measured fluxes, including: samplin...

  20. A Novel Infrared Gas Monitor

    NASA Astrophysics Data System (ADS)

    Wang, Yingding; Zhong, Hongjie

    2000-03-01

    In the paper a novel non-dispersive infrared(IR) gas monitor is described.It is based on the principle that certain gases absorb IR radiation at specific(and often unique) wavelengths.Conventional devices typically include several primary components:a broadband source, usually an incandescent filament,a rotating chopper shutter,a narrow-band filter,a sample tube and a detector. We have developed a number of IR light emitting diodes(LED) having narrow optical bandwidths and which can be intensity modulated by electrical means,for example InAsSbP(4.2 micron)LED.The IR LED can thus replace the thermal source,narrow-band filter and chopper assembly of the conventional IR gas monitor,yielding a solid state,low- powered,compact and almost maintenance-free instrument with high sensitivity and stability and which free of the effects of mechanical vibration too. The detector used in the IR gas monitor is the solid-state detector,such as PbS,PbSe, InSb,HgCdTe,TGS,LT and PZT detector etc. The different configuration of the IR gas monitor is designed.For example,two-path version for measuring methane concentration by monitoring the 3.31 micron absorption band,it can eliminate the interference effects,such as to compensate for LED intensity changes caused by power and temperature variations,and for signal fluctuations due to changes in detector bias. we also have designed portable single-beam version without the sample tube.Its most primary advantage is very cheap(about cost USD 30 ).It measures carbon dioxide concentration by monitoring the 4.25 micron absorption band.Thought its precisions is low,it is used to control carbon dioxide concentration in the air in the green houses and plastic houses(there are about twenty millon one in the China).Because more carbon dioxide will increase the quanity of vegetable and flower production to a greatextent. It also is used in medical,sanitary and antiepidemic applications,such as hospital, store,hotel,cabin and ballroom etc. Key words

  1. A new mini gas ionization chamber for IBA applications

    NASA Astrophysics Data System (ADS)

    Müller, A. M.; Cassimi, A.; Döbeli, M.; Mallepell, M.; Monnet, I.; Simon, M. J.; Suter, M.; Synal, H.-A.

    2011-12-01

    Novel prototypes of high resolution gas ionization chambers ( GIC) were designed with increased compactness and simplicity of the setup. They have no Frisch-grid and a simple anode wire. Under certain operating conditions these mini detectors have an energy resolution comparable with that of state-of-the-art GICs of much higher complexity. They can be operated both under vacuum and atmospheric pressure. First measurements were made with protons in the energy range of 0.3-1.0 MeV. For protons at 0.3 MeV an energy resolution of about 12 keV was achieved. With a 72 MeV 129Xe beam a relative resolution of 1.4% was obtained. Due to their versatility and reduced size the detectors can easily be applied in the field of ion beam analysis ( IBA) and accelerator mass spectrometry ( AMS) . Since they are almost completely insensitive to radiation damage they are especially suited for use in high fluence applications such as scanning transmission ion microscopy ( STIM). A comparison of the radiation hardness of the mini GIC with a Si PIN diode was therefore performed. The GIC showed no peak shift or change in energy resolution at all after collecting 10 15 protons per cm 2 while the performance of the Si detector clearly started to degrade at 10 12 particles per cm 2.

  2. Reply to comment on 'Proton beam monitor chamber calibration'.

    PubMed

    Gomà, Carles; Lorentini, Stefano; Meer, David; Safai, Sairos

    2016-09-01

    This reply shows that the discrepancy of about 3% between Faraday cup dosimetry and reference dosimetry using a cylindrical ionization chamber found in Gomà (2014 Phys. Med. Biol. 59 4961-71) seems to be due to an overestimation of the beam quality correction factors tabulated in IAEA TRS-398 for the cylindrical chamber used, rather than to 'unresolved problems with Faraday cup dosimetry', as suggested by Palmans and Vatnitsky (2016 Phys. Med. Biol. 61 6585-93). Furthermore, this work shows that a good agreement between reference dosimetry and Faraday cup dosimetry is possible, provided accurate beam quality correction factors for proton beams are used. The review on W air values presented by Palmans and Vatnitsky is believed to be inaccurate, as it is based on the imprecise assumption of ionization chamber perturbation correction factors in proton beams being equal to unity. PMID:27535895

  3. GEOPHYSICS, ASTRONOMY AND ASTROPHYSICS: Scaling of the flowfield in a combustion chamber with a gas-gas injector

    NASA Astrophysics Data System (ADS)

    Wang, Xiao-Wei; Cai, Guo-Biao; Jin, Ping

    2010-01-01

    The scaling of the flowfield in a gas-gas combustion chamber is investigated theoretically, numerically and experimentally. To obtain the scaling criterion of the gas-gas combustion flowfield, formulation analysis of the three-dimensional (3D) Navier-Stokes equations for a gaseous multi-component mixing reaction flow is conducted and dimensional analysis on the gas-gas combustion phenomena is also carried out. The criterion implies that the size and the pressure of the gas-gas combustion chamber can be changed. Based on the criterion, multi-element injector chambers with different geometric sizes and at different chamber pressures ranging from 3 MPa to 20 MPa are numerically simulated. A multi-element injector chamber is designed and hot-fire tested at five chamber pressures from 1.64 MPa to 3.68 MPa. Wall temperature measurements are used to understand the similarity of combustion flowfields in the tests. The results have verified the similarities between combustion flowfields under different chamber pressures and geometries, with the criterion applied.

  4. Government gas vans and school gas chambers: preparedness and paranoia in Britain, 1936-1941.

    PubMed

    Moshenska, Gabriel

    2010-01-01

    In 1936 the Air Raid Precautions department of the British Home Office instigated a training programme in which members of the public, including school students, were systematically exposed to tear gas. Based around fixed and mobile gas chambers, this training aimed to educate the public in the value and efficacy of their gas masks. Drawing on documentary and oral historical sources, this paper examines the discrepancies between the stated form and aims of these tests, and their practical applications, including some excessively brutal training practices. In the last part of the paper I consider these variations in the context of both the gas panic and the moral panic about children's behaviour in wartime. PMID:21291169

  5. Flushing induction chambers used for rodent anesthesia to reduce waste anesthetic gas.

    PubMed

    Wolforth, Janet; Dyson, Melissa C

    2011-03-01

    Anesthetic induction chambers used for medical research are a substantial source of waste anesthetic gas (WAG). Ideally, any generated waste gas should be actively vented away from personnel operating the chamber by either a ventilated hood or snorkel. Unfortunately, the ideal environment for anesthetizing rodents is not always available. In an effort to create a safer environment, the authors designed a system to reduce WAG. This system is portable, can be adapted to different precision vaporizing anesthetic systems and fits in a variety of physical locations. The system flushes anesthetic gas out of an induction chamber before operators open the chamber. To ensure that the system was adequately flushing the anesthetic gas, the authors measured WAG concentration in the environment above the induction chamber and directly behind the vent of an activated charcoal filter. They also compared the efficiency of the filters in vertical and horizontal positions. Finally, they measured the recovery time for mice and rats after flushing the anesthetic gas from an induction chamber. The results show that flushing the induction chamber was an inexpensive and effective method for reducing WAG accumulation in the air surrounding the chamber. PMID:21326188

  6. Pressure Loads by Gas in an Enclosed Chamber in DYNA3D

    SciTech Connect

    Lin, J; Badders, D C

    2002-08-08

    New algorithms that efficiently calculate the volume of a closed chamber are presented in this paper. The current pressure in the enclosed chamber can then be computed, based on the user-specified gas law, from the updated volume and the initial volume and pressure of the chamber. This pressure load function is very useful in modeling common features, such as air pocket, airbag, piston, and gun barrel, in structural analyses.

  7. Gas gain uniformity tests performed on multiwire proportional chambers for the LHCb muon system

    NASA Astrophysics Data System (ADS)

    Alves, A.; de Andrade Filho, L. M.; Barbosa, A. F.; Graulich, J. S.; Guerrer, G.; Lima, H. P.; Mair, K.; Polycarpo, E.; Reis, A.; Rodrigues, F.; Schmidt, B.; Schneider, T.; Schoch Vianna, C.

    2008-06-01

    We present the experimental setup and the results of the gas gain uniformity tests performed as part of the quality control of the multiwire proportional chambers produced at CERN for the LHCb muon system. The test provides a relative gas gain measurement over the whole chamber sensitive area. It is based on the analysis of the pulse height spectrum obtained when the chamber is exposed to a 241Am radioactive source. Since the measurement is normalized to the peak of a precise pulse generator, the gain uniformity can also be evaluated among different gas gaps and different chambers. In order to cope with the specific requirements related to the relatively high number of chambers and to their varying geometry, a standalone and compact data acquisition system has been developed which is programmable at the hardware level and may be applied to many other applications requiring precise time-to-digital and analog-to-digital conversion, in correlated or non-correlated mode.

  8. TRACE GAS EMISSIONS IN CHAMBERS: A NON-STEADY-STATE DIFFUSION MODEL

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Non-steady-state (NSS) chambers are widely used to measure trace gas emissions from the Earth’s surface in the atmosphere. Unfortunately, traditional interpretations of time-dependent chamber concentrations often systematically underestimate predeployment exchange rates because they do not accuratel...

  9. Evaluation of Gas-filled Ionization Chamber Method for Radon Measurement at Two Reference Facilities

    SciTech Connect

    Ishikawa, Tetsuo; Tokonami, Shinji; Kobayashi, Yosuke; Sorimachi, Atsuyuki; Yatabe, Yoshinori; Miyahara, Nobuyuki

    2008-08-07

    For quality assurance, gas-filled ionization chamber method was tested at two reference facilities for radon calibration: EML (USA) and PTB (Germany). Consequently, the radon concentrations estimated by the ionization chamber method were in good agreement with the reference radon concentrations provided by EML as well as PTB.

  10. DIFFUSION THEORY IMPROVES CHAMBER-BASED MEASUREMENTS OF TRACE GAS EMISSIONS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Chambers temporarily sealed to the soil surface are an important and for many purposes the only means of measuring trace gas emissions to the atmosphere. However, past interpretations of chamber data systematically underestimated actual emission rates in most applications because they ignored or poo...

  11. Minimizing field time to get reasonable greenhouse gas flux estimates from many chambers

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Greenhouse gas measurements from soil are typically derived from static chambers placed in several replicate field plots and in multiple locations within a plot. Inherent variability in emissions is due to a number of known and unknown factors. Getting robust emission estimates from numerous chamber...

  12. Passivation of micro-strip gas chambers with an interstitial germanium coating

    SciTech Connect

    Miyamoto, J.; Knoll, G.F.; Amos, N.

    1996-12-31

    Micro-strip gas chambers (MSGCs) were constructed in the Solid-State Electronics Laboratory of the University of Michigan and their performance was studied. Many efforts have been made in the past to construct MSGCs that yield high absolute gas gain and stable gas gain. Introducing a thin germanium layer has been effective for passivation but difficulties associated with the poor adhesiveness of the thin layer have been a serious obstacle. This paper reports on a new method used to overcome these difficulties. Unlike the conventional coating method the thin germanium layer was successfully deposited between the strip lines. This technique requires a careful geometric alignment of a second photomask with the original micro-strip structure. The resulting detector performance was noteworthy and an absolute gas gain of 2 {center_dot} 10{sup 4} was easily achieved by the new chamber. The chamber`s gain instability was also reduced significantly compared with those without interstitial coating.

  13. Study of avalanche mode operation of resistive plate chambers with different gas gap structures

    NASA Astrophysics Data System (ADS)

    Ammosov, V. V.; Gapienko, V. A.; Konstantinov, V. F.; Sviridov, Yu. M.; Zaets, V. G.

    2000-03-01

    The operation of narrow gap, wide gap and multigap resistive plate chambers in an avalanche mode was studied. No advantage in avalanche-streamer separation was found for the wide gap and multigap chambers operating with Ar-based mixture as compared with the narrow gap chamber. For dense tetrafluoroethane-based mixture, proportionality was observed between streamer-free plateau width and total gas thickness, in rough agreement with corresponding shift of the maximum of avalanche charge distributions from zero. The best result was obtained for double-gap chamber with the read-out electrode located between two subgaps.

  14. Modeling Gas Exchange in a Closed Plant Growth Chamber

    NASA Technical Reports Server (NTRS)

    Cornett, J. D.; Hendrix, J. E.; Wheeler, R. M.; Ross, C. W.; Sadeh, W. Z.

    1994-01-01

    Fluid transport models for fluxes of water vapor and CO2 have been developed for one crop of wheat and three crops of soybean grown in a closed plant a growth chamber. Correspondence among these fluxes is discussed. Maximum fluxes of gases are provided for engineering design requirements of fluid recycling equipment in growth chambers. Furthermore, to investigate the feasibility of generalized crop models, dimensionless representations of water vapor fluxes are presented. The feasibility of such generalized models and the need for additional data are discussed.

  15. Modeling gas exchange in a closed plant growth chamber

    NASA Technical Reports Server (NTRS)

    Cornett, J. D.; Hendrix, J. E.; Wheeler, R. M.; Ross, C. W.; Sadeh, W. Z.

    1994-01-01

    Fluid transport models for fluxes of water vapor and CO2 have been developed for one crop of wheat and three crops of soybean grown in a closed plant growth chamber. Correspondence among these fluxes is discussed. Maximum fluxes of gases are provided for engineering design requirements of fluid recycling equipment in growth chambers. Furthermore, to investigate the feasibility of generalized crop models, dimensionless representations of water vapor fluxes are presented. The feasibility of such generalized models and the need for additional data are discussed.

  16. A solid state gas density monitor for gas insulated substation equipment

    SciTech Connect

    Saaski, E.W.; Hartl, J.C.

    1982-07-01

    A solid state gas density monitor has been developed for SF/sub 6/ service in gas-insulated substation equipment that is based on principles and construction techniques similar to ionization-type fire alarms. The monitor has a resolution of .7kPa (.1 psi) at 20/sup 0/C and, depending on ion chamber voltage and geometry, exhibits a linearity of /sup +//sub -/1 to /sup +//sub -/4. kPa (/sup +//sub -/.15 to /sup +//sub -/.6 psi) at 20/sup 0/C over the density range 0.20 to 0.66 MPa (30 to 95 psia) at 20/sup 0/C. The monitor incorporates two level contact closure actuated by gas density falling below one of two pre-set alarm limits, and an LCD read-out for visual monitoring and instrument calibration. The display presents density in terms of equivalent psia at 68/sup 0/F. (20/sup 0/C.).

  17. Treadmill chamber for studies of respiratory gas exchange in the rat during exercise.

    PubMed

    Ardévol, A; Adán, C; Fernández-López, J A; Pérez, J; Corts, J L; Binagui, D; Remesar, X; Alemany, M

    1995-05-01

    A treadmill for studying gas exchange in small mammals during exercise is presented. The system consists of a motor-driven running mat enclosed in a gastight chamber that receives a measured flow of air from a compressed air cylinder. The gas flow and temperature, pressure and instantaneous gas composition of the chamber (oxygen, carbon dioxide and water) are measured continuously and the data are computed to include the effects on chamber atmosphere of the rat activity, either running or at rest. The system is completed with a shock delivery grid that stimulates the rat to run. The calculations are based on the changes in the composition of the gas in the chamber (constantly stirred by a small electric fan) induced by the rat instead of relying on the alterations induced in the outflowing gas. The consumption of oxygen, and production of carbon dioxide and water by the rat are computed in real time, giving a very fast response to physiological change induced by exercise. The chamber is custom-made from an aluminium block and a plexiglass lid; all other components are available commercially. The system, as described, allows for a detailed analysis of respiratory gas (and water) exchange by rats under varying exercise conditions, there is practically no time lag between changes in respiratory gases and the detection of these changes, and the buffering effect of the chamber size is practically eliminated because of the calculation approach used. PMID:9338089

  18. Spin Start Line Effects on the J2X Gas Generator Chamber Acoustics

    NASA Technical Reports Server (NTRS)

    Kenny, R. Jeremy

    2011-01-01

    The J2X Gas Generator engine design has a spin start line connected near to the turbine inlet vanes. This line provides helium during engine startup to begin turbomachinery operation. The spin start line also acts as an acoustic side branch which alters the chamber's acoustic modes. The side branch effectively creates 'split modes' in the chamber longitudinal modes, in particular below the first longitudinal mode and within the frequency range associated with the injection-coupled response of the Gas Generator. Interaction between the spin start-modified chamber acoustics and the injection-driven response can create a higher system response than without the spin start attached to the chamber. This work reviews the acoustic effects of the spin start line as seen throughout the workhorse gas generator test program. A simple impedance model of the spin start line is reviewed. Tests were run with no initial spin start gas existing in the line, as well as being initially filled with nitrogen gas. Tests were also run with varying spin start line lengths from 0" to 40". Acoustic impedance changes due to different spin start gas constituents and line lengths are shown. Collected thermocouple and static pressure data in the spin start line was used to help estimate the fluid properties along the line length. The side branch impedance model was coupled to a chamber impedance model to show the effects on the overall chamber response. Predictions of the spin start acoustic behavior for helium operation are shown and compared against available data.

  19. Development and test of combustion chamber for Stirling engine heated by natural gas

    NASA Astrophysics Data System (ADS)

    Li, Tie; Song, Xiange; Gui, Xiaohong; Tang, Dawei; Li, Zhigang; Cao, Wenyu

    2014-04-01

    The combustion chamber is an important component for the Stirling engine heated by natural gas. In the paper, we develop a combustion chamber for the Stirling engine which aims to generate 3˜5 kWe electric power. The combustion chamber includes three main components: combustion module, heat exchange cavity and thermal head. Its feature is that the structure can divide "combustion" process and "heat transfer" process into two apparent individual steps and make them happen one by one. Since natural gas can mix with air fully before burning, the combustion process can be easily completed without the second wind. The flame can avoid contacting the thermal head of Stirling engine, and the temperature fields can be easily controlled. The designed combustion chamber is manufactured and its performance is tested by an experiment which includes two steps. The experimental result of the first step proves that the mixture of air and natural gas can be easily ignited and the flame burns stably. In the second step of experiment, the combustion heat flux can reach 20 kW, and the energy utilization efficiency of thermal head has exceeded 0.5. These test results show that the thermal performance of combustion chamber has reached the design goal. The designed combustion chamber can be applied to a real Stirling engine heated by natural gas which is to generate 3˜5 kWe electric power.

  20. Wafer chamber having a gas curtain for extreme-UV lithography

    DOEpatents

    Kanouff, Michael P.; Ray-Chaudhuri, Avijit K.

    2001-01-01

    An EUVL device includes a wafer chamber that is separated from the upstream optics by a barrier having an aperture that is permeable to the inert gas. Maintaining an inert gas curtain in the proximity of a wafer positioned in a chamber of an extreme ultraviolet lithography device can effectively prevent contaminants from reaching the optics in an extreme ultraviolet photolithography device even though solid window filters are not employed between the source of reflected radiation, e.g., the camera, and the wafer. The inert gas removes the contaminants by entrainment.

  1. Study of Parameters Effect on Hydrodynamics of a Gas-Solid Chamber Experimentally and Numerically

    NASA Astrophysics Data System (ADS)

    Hamzehei, Mahdi; Rahimzadeh, Hassan

    2012-04-01

    In this research, gas velocity, initial static bed height and particle size effect on hydrodynamics of a non-reactive gas-solid fluidized bed chamber were studied experimentally and computationally. A multi fluid Eulerian model incorporating the kinetic theory for solid particles was applied to simulate the unsteady state behavior of this chamber and momentum exchange coefficients were calculated by using the Syamlal- O'Brien drag functions. Simulation results were compared with the experimental data in order to validate the CFD model. Pressure drops predicted by the simulations at different particle sizes and initial static bed height were in good agreement with experimental measurements at superficial gas velocity higher than the minimum fluidization velocity. Simulation results also indicated that small bubbles were produced at the bottom of the bed. These bubbles collided with each other as they moved upwards forming larger bubbles. Furthermore, this comparison showed that the model can predict hydrodynamic behavior of gas solid fluidized bed chambers reasonably well.

  2. Degradation in the efficiency of glass Resistive Plate Chambers operated without external gas supply

    NASA Astrophysics Data System (ADS)

    Baesso, P.; Cussans, D.; Thomay, C.; Velthuis, J.; Burns, J.; Quillin, S.; Stapleton, M.; Steer, C.

    2015-06-01

    Resistive plate chambers (RPC) are particle detectors commonly used by the high energy physics community. Their normal operation requires a constant flow of gas mixture to prevent self-poisoning which reduces the chamber's capability to detect particles. We studied how quickly the efficiency of two RPCs drops when operated in sealed mode, i.e. without refreshing the gas mixture. The test aim is to determine how RPCs could be used as particle detectors in non-laboratory applications, such as those exploiting muon tomography for geological imaging or homeland security. The two sealed RPCs were operated in proportional mode for a period of more than three months, and their efficiencies were recorded continuously and analysed in 8-hours intervals. The results show that the efficiency drops on average by 0.79 ± 0.01 % every 24 hours of operation and returns close to the initial value after purging the old gas mixture and flushing the chambers with fresh gas.

  3. Technical Note: Semi-rigid chambers for methane gas flux measurements on tree stems

    NASA Astrophysics Data System (ADS)

    Siegenthaler, Andy; Welch, Bertie; Pangala, Sunitha R.; Peacock, Michael; Gauci, Vincent

    2016-02-01

    There is increasing interest in the measurement of methane (CH4) emissions from tree stems in a wide range of ecosystems so as to determine how they contribute to the total ecosystem flux. To date, tree CH4 fluxes are commonly measured using rigid closed chambers (static or dynamic), which often pose challenges as these are bulky and limit measurement of CH4 fluxes to only a very narrow range of tree stem sizes and shapes. To overcome these challenges we aimed to design and test new semi-rigid stem-flux chambers (or sleeves). We compared the CH4 permeability of the new semi-rigid chambers with that of the traditional rigid chamber approach, in the laboratory and in the field, with continuous flow or syringe injections. We found that the semi-rigid chambers had reduced gas permeability and optimal stem gas exchange surface to total chamber volume ratio (Sc / Vtot) better headspace mixing, especially when connected in a dynamic mode to a continuous flow gas analyser. Semi-rigid sleeves can easily be constructed and transported in multiple sizes, are extremely light, cheap to build and fast to deploy. This makes them ideal for use in remote ecosystems where access logistics is complicated.

  4. Measurement of greenhouse gas flux from agricultural soils using static chambers.

    PubMed

    Collier, Sarah M; Ruark, Matthew D; Oates, Lawrence G; Jokela, William E; Dell, Curtis J

    2014-01-01

    Measurement of greenhouse gas (GHG) fluxes between the soil and the atmosphere, in both managed and unmanaged ecosystems, is critical to understanding the biogeochemical drivers of climate change and to the development and evaluation of GHG mitigation strategies based on modulation of landscape management practices. The static chamber-based method described here is based on trapping gases emitted from the soil surface within a chamber and collecting samples from the chamber headspace at regular intervals for analysis by gas chromatography. Change in gas concentration over time is used to calculate flux. This method can be utilized to measure landscape-based flux of carbon dioxide, nitrous oxide, and methane, and to estimate differences between treatments or explore system dynamics over seasons or years. Infrastructure requirements are modest, but a comprehensive experimental design is essential. This method is easily deployed in the field, conforms to established guidelines, and produces data suitable to large-scale GHG emissions studies. PMID:25146426

  5. Measurement of Greenhouse Gas Flux from Agricultural Soils Using Static Chambers

    PubMed Central

    Collier, Sarah M.; Ruark, Matthew D.; Oates, Lawrence G.; Jokela, William E.; Dell, Curtis J.

    2014-01-01

    Measurement of greenhouse gas (GHG) fluxes between the soil and the atmosphere, in both managed and unmanaged ecosystems, is critical to understanding the biogeochemical drivers of climate change and to the development and evaluation of GHG mitigation strategies based on modulation of landscape management practices. The static chamber-based method described here is based on trapping gases emitted from the soil surface within a chamber and collecting samples from the chamber headspace at regular intervals for analysis by gas chromatography. Change in gas concentration over time is used to calculate flux. This method can be utilized to measure landscape-based flux of carbon dioxide, nitrous oxide, and methane, and to estimate differences between treatments or explore system dynamics over seasons or years. Infrastructure requirements are modest, but a comprehensive experimental design is essential. This method is easily deployed in the field, conforms to established guidelines, and produces data suitable to large-scale GHG emissions studies. PMID:25146426

  6. Development of an ionization-type gas density monitor

    NASA Astrophysics Data System (ADS)

    Saaski, E. W.

    1980-12-01

    A battery operated electronic gas density monitor was developed for SF6 service in gas insulated substation equipment that is based on principles similar to ionization type fire alarms. The monitor has a resolution of 0.1 psia at 68 F and exhibits a linearity of from + or - 0.15 to + or - 0.6 psia at 68 F over the pressure range 30 to 75 psia, depending on ion chamber characteristics and operating voltage. A prototype unit exhibited a deviation from ideality of about 0.01% per degree Fahrenheit over the temperature range -30 F to 105 F and was found insensitive to water vapor in SF6 at levels in excess of 1000 ppM.

  7. Wire chamber

    DOEpatents

    Atac, Muzaffer

    1989-01-01

    A wire chamber or proportional counter device, such as Geiger-Mueller tube or drift chamber, improved with a gas mixture providing a stable drift velocity while eliminating wire aging caused by prior art gas mixtures. The new gas mixture is comprised of equal parts argon and ethane gas and having approximately 0.25% isopropyl alcohol vapor.

  8. Real-time dielectric-film thickness measurement system for plasma processing chamber wall monitoring

    NASA Astrophysics Data System (ADS)

    Kim, Jin-Yong; Chung, Chin-Wook

    2015-12-01

    An in-situ real-time processing chamber wall monitoring system was developed. In order to measure the thickness of the dielectric film, two frequencies of small sinusoidal voltage (˜1 V) signals were applied to an electrically floated planar type probe, which is positioned at chamber wall surface, and the amplitudes of the currents and the phase differences between the voltage and current were measured. By using an equivalent sheath circuit model including a sheath capacitance, the dielectric thickness can be obtained. Experiments were performed in various plasma condition, and reliable dielectric film thickness was obtained regardless of the plasma properties. In addition, availability in commercial chamber for plasma enhanced chemical vapor deposition was verified. This study is expected to contribute to the control of etching and deposition processes and optimization of periodic maintenance in semiconductor manufacturing process.

  9. Lean stability augmentation study. [on gas turbine combustion chambers

    NASA Technical Reports Server (NTRS)

    Mcvey, J. B.; Kennedy, J. B.

    1979-01-01

    An analytical conceptual design study and an experimental test program were conducted to investigate techniques and develop technology for improving the lean combustion limits of premixing, prevaporizing combustors applicable to gas turbine engine main burners. The use of hot gas pilots, catalyzed flameholder elements, and heat recirculation to augment lean stability limits was considered in the conceptual design study. Tests of flameholders embodying selected concepts were conducted at a pressure of 10 arm and over a range of entrance temperatures simulating conditions to be encountered during stratospheric cruise. The tests were performed using an axisymmetric flametube test rig having a nominal diameter of 10.2 cm. A total of sixteen test configurations were examined in which lean blowout limits, pollutant emission characteristics, and combustor performance were evaluated. The use of a piloted perforated plate flameholder employing a pilot fuel flow rate equivalent to 4 percent of the total fuel flow at a simulated cruise condition resulted in a lean blowout equivalence ratio of less than 0.25 with a design point (T sub zero = 600k, Phi = 0.6) NOx emission index of less than 1.0 g/kg.

  10. Accuracy and Precision Analysis of Chamber-Based Nitrous Oxide Gas Flux Estimates

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Chamber-based estimates of soil-to-atmosphere nitrous oxide (N2O) gas flux tend to underestimate actual emission rates due to inherently non-linear time series data. In theory, this limitation can be minimized by adjusting measurement conditions to reduce non-linearity and/or by using flux-calculati...

  11. Laboratory Connections. Gas Monitoring Transducers.

    ERIC Educational Resources Information Center

    Powers, Michael H.

    1988-01-01

    Discusses three types of sensors; pressure, gas detection, and relative humidity. Explains their use for laboratory measurements of gas pressure and detection of specific gaseous species. Shows diagrams of devices and circuits along with examples and applications including microcomputer interfacing. (RT)

  12. Ion Chambers for Monitoring the NuMI Neutrino Beam at Fermilab

    SciTech Connect

    Indurthy, Dharmaraj; Keisler, Ryan; Kopp, Sacha; Mendoza, Steven; Proga, Marek; Pavlovich, Zarko; Zwaska, Robert; Harris, Deborah; Marchionni, Alberto; Morfin, Jorge; Erwin, Albert; Ping Huicana; Velissaris, Christos; Naples, Donna; Northacker, Dave; McDonald, Jeff; Diwan, Milind; Viren, Brett

    2004-11-10

    The Neutrinos at the Main Injector (NuMI) beamline will deliver an intense muon neutrino beam by focusing a beam of mesons into a long evacuated decay volume. The beam must be steered with 1-mRad angular accuracy toward the Soudan Underground Laboratory in northern Minnesota. We have built 4 arrays of ionization chambers to monitor the neutrino beam direction and quality. The arrays are located at 4 stations downstream of the decay volume, and measure the remnant hadron beam and tertiary muons produced along with neutrinos in meson decays. We review how the monitors will be used to make beam quality measurements, and as well review chamber construction details, radiation damage testing, calibration, and test beam results.

  13. Apparatus for monitoring tritium in tritium-contaminating environments using a modified Kanne chamber

    DOEpatents

    Anderson, D.F.

    1981-01-27

    A conventional Kanne tritium monitor has been redesigned to reduce its sensitivity to such contaminants as tritiated water vapor and tritiated oil. The high voltage electrode has been replaced by a wire cylinder and the collector electrode has been reduced in diameter. The area sensitive to contamination has thereby been reduced by about a factor of forty while the overall apparatus sensitivity and operation has not been affected. The design allows for in situ decontamination of the chambers, if necessary.

  14. Apparatus for monitoring tritium in tritium contaminating environments using a modified Kanne chamber

    DOEpatents

    Anderson, David F.

    1984-01-01

    A conventional Kanne tritium monitor has been redesigned to reduce its sensitivity to such contaminants as tritiated water vapor and tritiated oil. The high voltage electrode has been replaced by a wire cylinder and the collector electrode has been reduced in diameter. The area sensitive to contamination has thereby been reduced by about a factor of forty while the overall apparatus sensitivity and operation has not been affected. The design allows for in situ decontamination of the chambers, if necessary.

  15. Calibration and performance of a secondary emission chamber as a beam intensity monitor

    SciTech Connect

    Sivertz, M.; Chiang, I-H,; Rusek, A.

    2011-03-28

    We report on a study of the behavior of a secondary emission chamber (SEC). We show the dependence of the SEC signal on the charge and velocity of the primary beam for beams of protons, and heavy ions including Helium, Neon, Chlorine and Iron. We fill the SEC with a selection of different gases including Hydrogen, Helium, Nitrogen, Argon, and air, studying the SEC response when it is acting as an ion chamber. We also investigate the behavior of the SEC at intermediate pressures between 10{sup -8} torr and atmospheric pressure. The SEC uses thin conducting foils as the source and collector of electrons in a vacuum chamber. When charged particles traverse the vacuum chamber, they pass through a series of thin conducting foils, alternating anode and cathode. Ionization produced in the cathode foils travels across the intervening gap due to an applied high voltage and is collected on the anode foils. Electron production is very inefficient because most of the ionization in the foils remains trapped within the foil due to the short range of most delta-rays and the work function of the foil. It is this inefficiency that allows the SEC to operate at high dose rates and short pulse duration where the standard ion chambers cannot function reliably. The SEC was placed in the NSRL ion beam to receive a variety of heavy ion beams under different beam conditions. We used these ion beams to study the response of the SEC to different species of heavy ion, comparing with proton beams. We studied the response to beam of different energies, and as a function of different counting rate. We compared the behaviour of the SEC when operating under positive and negative high voltage. The SEC can operate as an ion chamber if it is filled with gas. We measured the response of the SEC when filled with a variety of gases, from Hydrogen to Helium, Nitrogen, Argon and air. The performance of the SEC as an ion chamber is compared with the standard NSRL ion chamber, QC3. By evacuating the SEC and

  16. Characterization of an amplification read-out gas chamber with stacked GEM and MicromeGas detectors

    NASA Astrophysics Data System (ADS)

    Aiola, Salvatore

    2015-04-01

    Micro-Pattern Gas Detectors (MPGD) are a relatively new class of devices that allow gas amplification of charges. Amplification is achieved by exploiting the high field density generated in gaps or holes of the order of a few tens of microns. If carefully designed, the field lines are such that the ions produced in the amplification process are trapped by the device, thus avoiding the build-up of space charge (ion back flow) in the gas volume. This is a crucial capability, especially when these devices are employed as read-out chambers of large gaseous tracking detectors, such as a Time Projection Chamber (TPC). We report on a series of measurements aimed at characterizing the performance of an amplification read-out chamber consisting of a stack of two Gas Electron Multipliers (GEMs) on top of a MicromeGas. The combination of these two technologies has proven to be particularly useful: the presence of multiple amplification steps allows operation of the MicromeGas at a relatively low gain, thus suppressing the spark rate; in addition this setup further reduces the overall ion back flow, without hindering the energy resolution. Measurements of the energy resolution, the amplification factor and the ion back flow for different electric field configurations will be presented.

  17. Studies of Helium Based Gas Mixtures Using a Small Cell Drift Chamber

    SciTech Connect

    Heise, Jaret; /British Columbia U.

    2006-07-07

    An international collaboration is currently working on the construction and design of an asymmetric B Factory at the Stanford Linear Accelerator Center that will be ready to collect data in 1999. The main physics motivation for such a facility is to test the description and mechanism of CP violation in the Standard Model of particle physics and provide insight into the question of why more matter than antimatter is observed in the universe today. In particular, this experiment will measure CP violation in the decay of B mesons. In the early stages of this effort, the Canadian contingent proposed to build the central tracking chamber for the BaBar detector. Presently, a prototype drift chamber is in operation and studies are being performed to test some of the unique features of drift chamber design dictated by the conditions of the experiment. Using cosmic muons, it is possible to study tracking and pattern recognition in the prototype chamber, and therefore calculate the efficiency and spatial resolution of the prototype chamber cells. These performance features will be used to test whether or not the helium-based gas mixtures proposed for the BaBar drift chamber are a viable alternative to the more traditional argon-based gases.

  18. Numerical simulation of operation processes in the combustion chamber and gas generator of oxygen-methane liquid rocket engine

    NASA Astrophysics Data System (ADS)

    Kalmykov, G. P.; Larionov, A. A.; Sidlerov, D. A.; Yanchilin, L. A.

    2009-09-01

    The results of numerical simulations of processes in gas generators and combustion chambers operating on oxygen and methane are presented. Specific features of mixing, evaporation, and combustion of propellants have been investigated. The degree of combustion completeness in chambers with three types of injectors - coaxial-jet gas-liquid, liquid-liquid monopropellant, and bipropellant impinging-jets injectors - has been estimated.

  19. A telescience monitoring and control concept for a CELSS plant growth chamber

    NASA Technical Reports Server (NTRS)

    Rasmussen, Daryl N.; Mian, Arshad

    1989-01-01

    Consideration is given to the use of telescience to monitor and control a Space Station CELSS plant growth chamber (PGC). The proposed telescience control system contains controllers for PGC subsystems, a local master controller, and remote controllers. The benefits of telescience are discussed and the functional requirements of the PGC are outlined. A typical monitoring and control scenario is described. It is suggested that the proposed concept would provide remote access to a ground-based CELSS research facility, Space Station plant growth facilities, lunar-based CELSS facilities, and manned interplanetary spacecraft.

  20. An online proton beam monitor for cancer therapy based on ionization chambers with micro pattern readout

    NASA Astrophysics Data System (ADS)

    Basile, E.; Carloni, A.; Castelluccio, D. M.; Cisbani, E.; Colilli, S.; De Angelis, G.; Fratoni, R.; Frullani, S.; Giuliani, F.; Gricia, M.; Lucentini, M.; Santavenere, F.; Vacca, G.

    2012-03-01

    A unique compact LINAC accelerator for proton therapy is under development in Italy within the TOP-IMPLART project. The proton beam will reach the kinetic energy of 230 MeV, it will have a widely variable current intensity (0.1-10 μA, with average up to 3.5 nA) associated with a high pulse repetition frequency (1-3.5 μs long pulses at 10-100 Hz). The TOP-IMPLART system will provide a fully active 3+1D dose delivery, that is longitudinal (energy modulation), transverse active spot scanning, and current intensity modulation. These accelerator features will permit a highly conformational dose distribution, which therefore requires an effective, online, beam monitor system with wide dynamic range, good sensitivity, adequate spatial resolution and rapid response. In order to fulfill these requisites a new device is under development for the monitoring of the beam intensity profile, its centroid and direction; it is based on transmission, segmented, ionization chambers with typical active area of 100 × 100 mm2. Micro pattern x/y pad like design has been used for the readout plane in order to maximize the field uniformity, reduce the chamber thickness and obtain both beam coordinates on a single chamber. The chamber prototype operates in ionization region to minimize saturation and discharge effects. Simulations (based on FLUKA) have been carried on to study the perturbation of the chamber on the beam parameters and the effects on the delivered dose (on a water phantom). The charge collected in each channel is integrated by dedicated auto-ranging readout electronics: an original scheme has been developed in order to have an input dynamic range greater than 104 with sensitivity better than 3%. This is achieved by a dynamical adjustment of the integrating capacitance to the signal intensity.

  1. Polymer growth rate in a wire chamber with oxygen, water, or alcohol gas additives

    NASA Astrophysics Data System (ADS)

    Boyarski, Adam M.

    2009-06-01

    The rate of polymer growth on wires was measured in a wire chamber while the chamber was aged initially with helium:isobutane (80:20) gas, and then with either oxygen, water, or alcohol added to the gas. At the completion of the aging process for each gas mixture, the carbon content on the wires was measured in a scanning electron microscope/energy dispersive X-ray (SEM/EDX) instrument. The same physical wires were used in all the gas mixtures, allowing measurement of polymer build-up or polymer depletion by each gas additive. It is found that the rate of polymer growth is not changed by the presence of oxygen, water, or alcohol. Conjecture that oxygen reduces breakdown by removing polymer deposits on field wires is negated by these measurements. Instead, it appears that the reduced breakdown is due to lower resistance in the polymer from oxygen ions being transported into the polymer. It is also observed that field wires bombarded by the electrons in the SEM and then placed back into the chamber show an abundance of single electrons being emitted, indicating that electron charge is trapped in the polymer layer and that a high electric field is necessary to remove the charge.

  2. Polymer Growth Rate in a Wire Chamber with Oxygen,Water, or Alcohol Gas Additives

    SciTech Connect

    Boyarski, Adam; /SLAC

    2008-07-02

    The rate of polymer growth on wires was measured in a wire chamber while the chamber was aged initially with helium-isobutane (80:20) gas, and then with either oxygen, water, or alcohol added to the gas. At the completion of the aging process for each gas mixture, the carbon content on the wires was measured in a SEM/EDX instrument. The same physical wires were used in all the gas mixtures, allowing measurement of polymer build up or polymer depletion by each gas additive. It is found that the rate of polymer growth is not changed by the presence of oxygen, water or alcohol. Conjecture that oxygen reduces breakdown by removing polymer deposits on field wires is negated by these measurements. Instead, it appears that the reduced breakdown is due to lower resistance in the polymer from oxygen ions being transported into the polymer. It is also observed that field wires bombarded by the electrons in the SEM and then placed back into the chamber show an abundance of single electrons being emitted, indicating that electron charge is stored in the polymer layer and that a high electric field is necessary to remove the charge.

  3. Experimental and Numerical Research of a Novel Combustion Chamber for Small Gas Turbine Engines

    NASA Astrophysics Data System (ADS)

    Tuma, J.; Kubata, J.; Betak, V.; Hybl, R.

    2013-04-01

    New combustion chamber concept (based on burner JETIS-JET Induced Swirl) for small gas turbine engine (up to 200kW) is presented in this article. The combustion chamber concept is based on the flame stabilization by the generated swirl swirl generated by two opposite tangentially arranged jet tubes in the intermediate zone, this arrangement replaces air swirler, which is very complicated and expensive part in the scope of small gas turbines with annular combustion chamber. The mixing primary jets are oriented partially opposite to the main exhaust gasses flow, this enhances hot product recirculation and fuel-air mixing necessary for low NOx production and flame stability. To evaluate the designed concept a JETIS burner demonstrator (methane fuel) was manufactured and atmospheric experimental measurements of CO, NOx for various fuel nozzles and jet tubes the configuration were done. Results of these experiments and comparison with CFD simulation are presented here. Practical application of the new chamber concept in small gas turbine liquid fuel combustor was evaluated (verified) on 3 nozzles planar combustor sector test rig at atmospheric conditions results of the experiment and numerical simulation are also presented.

  4. Photochemical transformation of flue gas from a coal-fired power plant: a smog chamber study

    SciTech Connect

    Olszyna, K.J.; Luria, M.; Meagher, J.F.

    1982-06-01

    In this study, the relationship between the formation of sulfate aerosols and other secondary products and various environmental parameters is reported. Actual flue gas is used in these experiments which were conducted in smog chambers. Smog chamber techniques and instrumentation have progressed recently and are being utilized for the purposes of this study to simulate urban smog with emphasis on the photochemistry of sulfur dioxide. The purpose for examining the oxidation process of SO/sub 2/ to sulfate aerosols is because of the implication of sulfates in health effects, visibility degradation, and acidic precipitation.

  5. Theoretical model for diffusive greenhouse gas fluxes estimation across water-air interfaces measured with the static floating chamber method

    NASA Astrophysics Data System (ADS)

    Xiao, Shangbin; Wang, Chenghao; Wilkinson, Richard Jeremy; Liu, Defu; Zhang, Cheng; Xu, Wennian; Yang, Zhengjian; Wang, Yuchun; Lei, Dan

    2016-07-01

    Aquatic systems are sources of greenhouse gases on different scales, however the uncertainty of gas fluxes estimated using popular methods are not well defined. Here we show that greenhouse gas fluxes across the air-water interface of seas and inland waters are significantly underestimated by the currently used static floating chamber (SFC) method. We found that the SFC CH4 flux calculated with the popular linear regression (LR) on changes of gas concentration over time only accounts for 54.75% and 35.77% of the corresponding real gas flux when the monitoring periods are 30 and 60 min respectively based on the theoretical model and experimental measurements. Our results do manifest that nonlinear regression models can improve gas flux estimations, while the exponential regression (ER) model can give the best estimations which are close to true values when compared to LR. However, the quadratic regression model is proved to be inappropriate for long time measurements and those aquatic systems with high gas emission rate. The greenhouse gases effluxes emitted from aquatic systems may be much more than those reported previously, and models on future scenarios of global climate changes should be adjusted accordingly.

  6. High-pressure gas quenching in cold chambers for increased cooling capacity

    SciTech Connect

    Segerberg, S.; Troell, E.

    1996-12-31

    Gas quenching for the hardening of steel parts is a lower-pollution alternative to quenching in quenchants such as oil or salt. As the surfaces of the cooled parts remain clean after gas quenching, there is no need to wash them after heat treatment, which reduces the consumption of oils and detergents. The fire risk and ventilation requirements of oil quenching are eliminated. In addition, some trials have shown that gas quenching has a positive effect on distortion, representing a saving in finishing work and thus a reduction in costs. Today, gas quenching is used almost solely in vacuum furnaces. Quenching is normally performed in the same chamber as heating, which means that besides quenching the batch, the quenching system must also remove heat from the heating elements and insulation of the furnace. Previous trials performed by IVF have shown that gas quenching with helium of ball bearing and carburizing steels (and other steels) in sizes up to 25 mm at pressures up to 20 bar in a vacuum furnace can achieve quenching rates and hardnesses similar to those achieved by hot quenching oils. This quenching performance is not, however, capable of dealing with larger sizes or lower-alloy steels. At IVF`s request, ALD Vacuum Technologies GmbH has developed a cold high-pressure gas quenching chamber that is independent of the furnace. As a result, there is no need to cool insulation or heating elements. Quenching can be carried out in the chamber at pressures of up to 40 bar for helium or up to 10 bar for nitrogen. The quenching chamber has been supplied to IVF, and has been used for experimental quenching of steel test pieces and components. Temperatures have been recorded by using some Inconel 600 test probes, {phi} 12,5 x 60 mm, with thermocouples in their centers.

  7. Monitoring the primo vascular system in lymphatic vessels by using window chambers

    PubMed Central

    Kim, Jungdae; Kim, Dong-Hyun; Jung, Sharon Jiyoon; Gil, Hyun-Ji; Yoon, Seung Zhoo; Kim, Young-Il; Soh, Kwang-Sup

    2016-01-01

    This study aims to develop a window chamber system in the skin of rats and to monitor the primo vascular system (PVS) inside the lymphatic vessels along the superficial epigastric vessels. The PVS in lymphatic vessels has been observed through many experiments under in vivo conditions, but monitoring the in vivo PVS in situ inside lymphatic vessels for a long time is difficult. To overcome the obstacles, we adapted the window chamber system for monitoring the PVS and Alcian blue (AB) staining dye solution for the contrast agent. The lymphatic vessels in the skin on the lateral side of the body, connecting the inguinal lymph nodes to the axillary lymph nodes, were the targets for setting the window system. After AB had been injected into the inguinal lymph nodes with a glass capillary, the morphological changes of the stained PVS were monitored through the window system for up to twenty hours, and the changes in the AB intensity in the PVS were quantified by using image processing. The results and histological images are presented in this study. PMID:27446651

  8. Monitoring the primo vascular system in lymphatic vessels by using window chambers.

    PubMed

    Kim, Jungdae; Kim, Dong-Hyun; Jung, Sharon Jiyoon; Gil, Hyun-Ji; Yoon, Seung Zhoo; Kim, Young-Il; Soh, Kwang-Sup

    2016-04-01

    This study aims to develop a window chamber system in the skin of rats and to monitor the primo vascular system (PVS) inside the lymphatic vessels along the superficial epigastric vessels. The PVS in lymphatic vessels has been observed through many experiments under in vivo conditions, but monitoring the in vivo PVS in situ inside lymphatic vessels for a long time is difficult. To overcome the obstacles, we adapted the window chamber system for monitoring the PVS and Alcian blue (AB) staining dye solution for the contrast agent. The lymphatic vessels in the skin on the lateral side of the body, connecting the inguinal lymph nodes to the axillary lymph nodes, were the targets for setting the window system. After AB had been injected into the inguinal lymph nodes with a glass capillary, the morphological changes of the stained PVS were monitored through the window system for up to twenty hours, and the changes in the AB intensity in the PVS were quantified by using image processing. The results and histological images are presented in this study. PMID:27446651

  9. Laser surface inspections: fundamentals and applications to monitor inner surface conditions of nuclear fusion reactor chambers

    NASA Astrophysics Data System (ADS)

    Kasuya, Koichi; Ozawa, S.; Norimatsu, T.; Azechi, H.; Mima, K.; Nakai, S.; Suzuki, S.; Budner, B.; Mroz, W.; Kasuya, N.; Kasuya, W.; Kasuya, Kei.; Izawa, Y.; Furukawa, H.; Shimada, Y.; Yamanaka, T.; Nakai, M.; Nagai, K.; Yokoyama, K.; Ezato, K.; Enoeda, M.; Akiba, M.; Prokopiuk, A.

    2010-09-01

    The most recent fundamental research results to investigate surface erosions of nuclear fusion candidate chamber materials are described in short. We used a commercial surface profiler with a red semiconductor laser. Various material surfaces ablated and eroded by a rather short pulse electron beam and a short pulse ArF laser light were measured with this surface profiler and the associated three-dimensional analysis software. Threshold input levels for various sample surface erosions with electron and laser beams were clearly decided for the first time with our new method in this article. After the above fundamental results were gathered, the methods to inspect inner surface conditions of nuclear fusion reactor chambers were newly proposed with various kinds of laser displacement sensors. The first one is the erosion monitor with the above profiler, and the second one is the laser induced ultrasonic wave detection method to inspect deeper surface layers than the first one.

  10. Innovative High Gas Pressure Microscopy Chamber Designed for Biological Cell Observation.

    PubMed

    Ragon, Mélanie; Nguyen Thi Minh, Hue; Guyot, Stéphane; Loison, Pauline; Burgaud, Gaëtan; Dupont, Sébastien; Beney, Laurent; Gervais, Patrick; Perrier-Cornet, Jean-Marie

    2016-02-01

    An original high-pressure microscopy chamber has been designed for real-time visualization of biological cell growth during high isostatic (gas or liquid) pressure treatments up to 200 MPa. This new system is highly flexible allowing cell visualization under a wide range of pressure levels as the thickness and the material of the observation window can be easily adapted. Moreover, the design of the observation area allows different microscope objectives to be used as close as possible to the observation window. This chamber can also be temperature controlled. In this study, the resistance and optical properties of this new high-pressure chamber have been tested and characterized. The use of this new chamber was illustrated by a real-time study of the growth of two different yeast strains - Saccharomyces cerevisiae and Candida viswanathii - under high isostatic gas pressure (30 or 20 MPa, respectively). Using image analysis software, we determined the evolution of the area of colonies as a function of time, and thus calculated colony expansion rates. PMID:26810277

  11. Web-based monitoring tools for Resistive Plate Chambers in the CMS experiment at CERN

    NASA Astrophysics Data System (ADS)

    Kim, M. S.; Ban, Y.; Cai, J.; Li, Q.; Liu, S.; Qian, S.; Wang, D.; Xu, Z.; Zhang, F.; Choi, Y.; Kim, D.; Goh, J.; Choi, S.; Hong, B.; Kang, J. W.; Kang, M.; Kwon, J. H.; Lee, K. S.; Lee, S. K.; Park, S. K.; Pant, L. M.; Mohanty, A. K.; Chudasama, R.; Singh, J. B.; Bhatnagar, V.; Mehta, A.; Kumar, R.; Cauwenbergh, S.; Costantini, S.; Cimmino, A.; Crucy, S.; Fagot, A.; Garcia, G.; Ocampo, A.; Poyraz, D.; Salva, S.; Thyssen, F.; Tytgat, M.; Zaganidis, N.; Doninck, W. V.; Cabrera, A.; Chaparro, L.; Gomez, J. P.; Gomez, B.; Sanabria, J. C.; Avila, C.; Ahmad, A.; Muhammad, S.; Shoaib, M.; Hoorani, H.; Awan, I.; Ali, I.; Ahmed, W.; Asghar, M. I.; Shahzad, H.; Sayed, A.; Ibrahim, A.; Aly, S.; Assran, Y.; Radi, A.; Elkafrawy, T.; Sharma, A.; Colafranceschi, S.; Abbrescia, M.; Calabria, C.; Colaleo, A.; Iaselli, G.; Loddo, F.; Maggi, M.; Nuzzo, S.; Pugliese, G.; Radogna, R.; Venditti, R.; Verwillingen, P.; Benussi, L.; Bianco, S.; Piccolo, D.; Paolucci, P.; Buontempo, S.; Cavallo, N.; Merola, M.; Fabozzi, F.; Iorio, O. M.; Braghieri, A.; Montagna, P.; Riccardi, C.; Salvini, P.; Vitulo, P.; Vai, I.; Magnani, A.; Dimitrov, A.; Litov, L.; Pavlov, B.; Petkov, P.; Aleksandrov, A.; Genchev, V.; Iaydjiev, P.; Rodozov, M.; Sultanov, G.; Vutova, M.; Stoykova, S.; Hadjiiska, R.; Ibargüen, H. S.; Morales, M. I. P.; Bernardino, S. C.; Bagaturia, I.; Tsamalaidze, Z.; Crotty, I.

    2014-10-01

    The Resistive Plate Chambers (RPC) are used in the CMS experiment at the trigger level and also in the standard offline muon reconstruction. In order to guarantee the quality of the data collected and to monitor online the detector performance, a set of tools has been developed in CMS which is heavily used in the RPC system. The Web-based monitoring (WBM) is a set of java servlets that allows users to check the performance of the hardware during data taking, providing distributions and history plots of all the parameters. The functionalities of the RPC WBM monitoring tools are presented along with studies of the detector performance as a function of growing luminosity and environmental conditions that are tracked over time.

  12. Open-system chamber for measurements of gas exchanges at plant level.

    PubMed

    Alterio, Giovanni; Giorio, Pasquale; Sorrentino, Giuseppe

    2006-03-15

    Gas exchanges of whole canopy can be studied by covering entire plants with a chamber and using portable infrared gas analyzers (IRGAs) to measure CO2 and H2O exchanged with the air blown through the chamber enclosure. The control of temperature rise inside the chamber, which should be kept low, and the accurate measurement of the air flow are two crucial aspects for realistic and precise estimation of photosynthesis and transpiration. An automated open-system plant chamber (clear flexible balloon enclosure) for small plants was developed to ameliorate such a technique. The temperature rise is here predicted by heat balance analysis inside the chamber. The analysis shows that when as much as 500 W m2 of solar radiation is converted to sensible heat, a flow rate of 0.98 mol s(-1) (approximately = 20 L s(-1)) of air blown into a cylinder-shaped enclosure (0.8 m high, 0.5 m wide) is adequate to limit temperature increase to 2 K. An improved calibration for the measurement of the chamber airflow was obtained by combining the use of a Pitot tube anemometer with the classical CO2 injection approach. The concentration increase due to the injection of CO2 at a known rate into the chamber was predicted by the air flow calculated from the "Pitot" air velocity. The turbulent regime of air assured that a single-point Pitot measurement was enough for a good estimation (slope = 0.99; R2 = 0.999) of the actual air flow. The open-system chamber was tested on potted sunflower (Helianthus annuus, L.) and maize (Zea mays, L.) plants under variable solar radiation, temperature, and air humidity during the daytime. As expected, similar rates of maximal leaf-area based photosynthesis (about 40 micromol m(-2) s(-1)) were observed in the two species confirming the reliability of our system. The consistency of data also resulted from the typical relationships observed between photosynthetic rate and light. PMID:16570620

  13. Computational Modeling of the Working Process in the Combustion Chamber for Casing-Head Gas Recovery

    NASA Astrophysics Data System (ADS)

    Bachev, N. L.; Betinskaya, O. A.; Bul‧bovich, R. V.

    2016-01-01

    The present paper considers problems of computational modeling of the working process in multizone combustion chambers (CC) forming a part of gas-turbine power plants for recovering casing-head and other process gases. To investigate the turbulent flow and combustion, we use the LES method with a Smagorinskii subnet model. Various schemes of feeding components into combustion and dilution zones are considered. A comparison is made between the calculated and experimental data on the temperature in the combustion zone.

  14. AXEL: High pressure xenon gas Time Projection Chamber for neutrinoless double beta decay search

    NASA Astrophysics Data System (ADS)

    Pan, Sheng

    2016-05-01

    AXEL is a high pressure xenon gas TPC detector being developed for neutrinoless double-beta decay search. We use proportional scintillation mode with a new electroluminescence light detection scheme to achieve very high energy resolution with a large detector. The detector has a capability of tracking which can be used reduce background. The project is in a R&D phase, and we report current status of our prototype chamber with 10 L and 8 bar Xe gas. We also present the results of the photon detection efficiency measurement and the linearity test of silicon photomultiplier(SiPM).

  15. Hot-gas-side heat transfer characteristics of subscale, plug-nozzle rocket calorimeter chamber

    NASA Technical Reports Server (NTRS)

    Quentmeyer, Richard J.; Roncace, Elizabeth A.

    1993-01-01

    An experimental investigation was conducted to determine the hot-gas-side heat transfer characteristics for a liquid-hydrogen-cooled, subscale, plug-nozzle rocket test apparatus. This apparatus has been used since 1975 to evaluate rocket engine advanced cooling concepts and fabrication techniques, to screen candidate combustion chamber liner materials, and to provide data for model development. In order to obtain the data, a water-cooled calorimeter chamber having the same geometric configuration as the plug-nozzle test apparatus was tested. It also used the same two showerhead injector types that were used on the test apparatus: one having a Rigimesh faceplate and the other having a platelet faceplate. The tests were conducted using liquid oxygen and gaseous hydrogen as the propellants over a mixture ratio range of 5.8 to 6.3 at a nominal chamber pressure of 4.14 MPa abs (600 psia). The two injectors showed similar performance characteristics with the Rigimesh faceplate having a slightly higher average characteristic-exhaust-velocity efficiency of 96 percent versus 94.4 percent for the platelet faceplate. The throat heat flux was 54 MW/m(sup 2) (33 Btu/in.(sup 2)-sec) at the nominal operating condition, which was a chamber pressure of 4.14 MPa abs (600 psia), a hot-gas-side wall temperature of 730 K (1314 R), and a mixture ratio of 6.0. The chamber throat region correlation coefficient C(sub g) for a Nusselt number correlation of the form Nu =C(sub g)Re(sup 0.8)Pr(sup 0.3) averaged 0.023 for the Rigimesh faceplate and 0.026 for the platelet faceplate.

  16. Monitoring Liquid Argon Time Projection Chambers With A Raspberry Pi Camera

    NASA Astrophysics Data System (ADS)

    Patteson, Crystal

    2016-03-01

    The MicroBooNE detector is the first of three liquid argon (LAr) time projection chambers (TPCs) that are central to the short-baseline neutrino program at Fermilab. These chambers consist of thousands of stainless steel or beryllium-copper sense wires that detect ionization electrons produced when neutrinos interact with liquid argon nuclei inside the detector. The wires are several hundred microns in diameter to several meters in length. The construction of such LAr TPCs often takes place in an assembly hall, which is different from the detector hall where the experiment will operate, as was the case with MicroBooNE. Since in situ access to the chamber and its wires in the beamline enclosure can be limited, we investigate the possibility of using a Raspberry Pi single-board computer connected to a low-cost camera installed inside the cryostat as a cost-efficient way to verify the integrity of the wires after transport. We also highlight other benefits of this monitoring device implemented in MicroBooNE, including detector hall surveillance and verification of the status of LED indicators on detector electronics. The author would like to thank Dr. Matthew Toups for his encouragement and guidance on this research project.

  17. Monitoring soil greenhouse gas emissions from managed grasslands

    NASA Astrophysics Data System (ADS)

    Díaz-Pinés, Eugenio; Lu, Haiyan; Butterbach-Bahl, Klaus; Kiese, Ralf

    2014-05-01

    Grasslands in Central Europe are of enormous social, ecological and economical importance. They are intensively managed, but the influence of different common practices (i.e. fertilization, harvesting) on the total greenhouse gas budget of grasslands is not fully understood, yet. In addition, it is unknown how these ecosystems will react due to climate change. Increasing temperatures and changing precipitation will likely have an effect on productivity of grasslands and on bio-geo-chemical processes responsible for emissions of carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O). In the frame of the TERENO Project (www.tereno.net), a long-term observatory has been implemented in the Ammer catchment, southern Germany. Acting as an in situ global change experiment, 36 big lysimeters (1 m2 section, 150 cm height) have been translocated along an altitudinal gradient, including three sites ranging from 600 to 860 meters above sea level. In addition, two treatments have been considered, corresponding to different management intensities. The overall aim of the pre-alpine TERENO observatory is improving our understanding of the consequences of climate change and management on productivity, greenhouse gas balance, soil nutritional status, nutrient leaching and hydrology of grasslands. Two of the sites are equipped with a fully automated measurement system in order to continuously and accurately monitor the soil-atmosphere greenhouse gas exchange. Thus, a stainless steel chamber (1 m2 section, 80 cm height) is controlled by a robotized system. The chamber is hanging on a metal structure which can move both vertically and horizontally, so that the chamber is able to be set onto each of the lysimeters placed on the field. Furthermore, the headspace of the chamber is connected with a gas tube to a Quantum Cascade Laser, which continuously measures CO2, CH4, N2O and H2O mixing ratios. The chamber acts as a static chamber and sets for 15 minutes onto each lysimeter

  18. Continuous blood gas monitoring in femoral arteries

    NASA Astrophysics Data System (ADS)

    Schlain, Les A.; Spar, Steven M.; Dellinger, Bart

    1995-05-01

    Continuous intra-arterial blood gas monitoring is a potentially valuable tool in the surgical and intensive care arenas. Patient oxygenation and acid base status can change rapidly and without warning. The ability to monitor pHa, PaCO2 and PaO2 in arterial blood will be a major medical advance for the anesthesiologist and intensivist. Intra-arterial blood gas sensors are typically placed in radial arteries. In certain patient populations accurate monitoring is not possible in radial arteries due to arterial environmental factors such as hypotension, vasoconstriction and atherosclerotic disease. These same factors can make radial cannulation difficult resulting in traumatic catheter insertion, thereby further compromising flow conditions. In situations where radial artery flow is expected to be compromised, selecting a large vessel for sensor placement is desirable. We report an initial feasibility study of our blood gas monitoring system using the femoral artery as the sensing site. Clinical results are presented as well as potential advantages and disadvantages associated with monitoring in the femoral artery.

  19. Architectural design of flue gas continuous emission monitoring system

    NASA Astrophysics Data System (ADS)

    Zhou, Hongfu; Jiang, Liangzhong; Tang, Yong; Yao, Xifan

    2008-10-01

    The paper presents the architectural design of flue gas continuous emission monitoring system, which uses computer, acquisition card and serial port communication card as hardware in the flue gas continuous emission monitoring system. In the CEMS, continuous emission monitoring system, it monitors dust in the flue gas, SO2, NOX, and some parameter on the flue gas emission, which includes mass flow, pressure, and temperature. For the software in the monitoring system, the research designs monitoring program in VC++, and realizes flue gas monitor with the architecture.

  20. Preliminary Investigation of a Ceramic Lining for a Combustion Chamber for Gas-turbine Use

    NASA Technical Reports Server (NTRS)

    Woodward, William H; Bobrowsky, A R

    1948-01-01

    Combustion chamber liners for gas turbines and experimental set-ups were tested for failure. A ceramic-lined test chamber was operated at fuel/air ratios up to 0.050. Thermal-shock evaluation indicated that a ceramic lining, which expands after firing, would crack but would not fall apart during operation. Refractoriness of the lining and the resistance to mechanical shock were adequate. In general, shell temperature reductions of approximately 400 deg F were effected by the use of this lining at fuel/air ratios of 0.016 and 0.050. The mechanism of failure of the ceramic lining was induced by sudden heating and cooling during operation.

  1. Development and performance of resistive seamless straw-tube gas chambers

    NASA Astrophysics Data System (ADS)

    Takubo, Y.; Aoki, M.; Ishihara, A.; Ishii, J.; Kuno, Y.; Maeda, F.; Nakahara, K.; Nosaka, N.; Sakamoto, H.; Sato, A.; Terai, K.; Igarashi, Y.; Yokoi, T.

    2005-10-01

    A new straw-tube gas chamber which is made of seamless straw-tubes, instead of ordinary wound-type straw-tubes is developed. Seamless straw-tubes have various advantages over ordinary wound-type ones, in particular, in terms of mechanical strength and lesser wall thickness. Our seamless straw-tubes are fabricated to be resistive so that the hit positions along the straw axis can be read by cathode planes placed outside the straw-tube chambers, where the cathode strips run transverse to the straw axis. A beam test was carried out at KEK to study their performance. As a result of the beam test, the position resolution of the cathode strips of 220 μm is achieved, and an anode position resolution of 112 μm is also obtained.

  2. Energy resolution of gas ionization chamber for high-energy heavy ions

    NASA Astrophysics Data System (ADS)

    Sato, Yuki; Taketani, Atsushi; Fukuda, Naoki; Takeda, Hiroyuki; Kameda, Daisuke; Suzuki, Hiroshi; Shimizu, Yohei; Nishimura, Daiki; Fukuda, Mitsunori; Inabe, Naohito; Murakami, Hiroyuki; Yoshida, Koichi; Kubo, Toshiyuki

    2014-01-01

    The energy resolution is reported for high-energy heavy ions with energies of nearly 340 MeV/nucleon and was measured using a gas ionization chamber filled with a 90%Ar/10%CH4 gas mixture. We observed that the energy resolution is proportional to the inverse of the atomic number of incident ions and to the inverse-square-root of the gas thickness. These results are consistent with the Bethe-Bloch formula for the energy loss of charged particles and the Bohr expression for heavy ion energy straggling. In addition, the influence of high-energy δ-rays generated in the detector on the energy deposition is discussed.

  3. A hierarchical modeling approach to estimating soil trace gas fluxes from static chambers

    NASA Astrophysics Data System (ADS)

    Ogle, K.; Ryan, E.; Dijkstra, F. A.; Pendall, E.

    2014-12-01

    Static chambers are often employed to measure soil trace gas fluxes. Gas concentrations (C) in the headspace are sampled at different times (t), and for each group of chamber measurements, flux rates are frequently calculated as the slope of linear regressions of C versus t (ultimately, statistical analyses are performed with the flux rate "data"). While non-linear regressions are recognized to be more accurate than linear regressions, a trade-off with precision can arise due to variability in raw data leading to poor curve fits, and groups of data with too few observations or with poor regression fits (i.e., low R2) are often discarded. We solve these problems via a hierarchical Bayesian approach that fits a simple, dynamic non-linear model of C versus t based on Fick's law. Data are from the Prairie Heating and CO2 Enrichment (PHACE) study that involves manipulations of atmospheric CO2, temperature, soil moisture, and vegetation. CO2, CH4, and N2O gas samples were collected from static chambers bi-weekly during five growing seasons, resulting in >12,000 individual gas samples and >3100 groups of samples and associated fluxes. Using these data, we compare flux estimates from our non-linear model to those obtained from a linear model, and we evaluate the effect of conducting independent regressions for each group of samples versus simultaneously estimating the fluxes for all groups within a hierarchical framework motivated by the PHACE experimental design. The CO2 flux estimates from the hierarchical linear and non-linear models fit the observed CO2 data well (R2 = 0.97) and were highly correlated with each other (r = 0.99), but the linear model resulted in estimates that were ~10% lower than the non-linear model. The hierarchical versus non-hierarchical models also produced similar flux estimates (r = 0.94), but the non-hierarchical version yielded notably less precise estimates (the 95% CIs for its fluxes were 1-2 orders of magnitude wider that the hierarchical

  4. Magmatic gas scrubbing: Implications for volcano monitoring

    USGS Publications Warehouse

    Symonds, R.B.; Gerlach, T.M.; Reed, M.H.

    2001-01-01

    Despite the abundance of SO2(g) in magmatic gases, precursory increases in magmatic SO2(g) are not always observed prior to volcanic eruption, probably because many terrestrial volcanoes contain abundant groundwater or surface water that scrubs magmatic gases until a dry pathway to the atmosphere is established. To better understand scrubbing and its implications for volcano monitoring, we model thermochemically the reaction of magmatic gases with water. First, we inject a 915??C magmatic gas from Merapi volcano into 25??C air-saturated water (ASW) over a wide range of gas/water mass ratios from 0.0002 to 100 and at a total pressure of 0.1 MPa. Then we model closed-system cooling of the magmatic gas, magmatic gas-ASW mixing at 5.0 MPa, runs with varied temperature and composition of the ASW, a case with a wide range of magmatic-gas compositions, and a reaction of a magmatic gas-ASW mixture with rock. The modeling predicts gas and water compositions, and, in one case, alteration assemblages for a wide range of scrubbing conditions; these results can be compared directly with samples from degassing volcanoes. The modeling suggests that CO2(g) is the main species to monitor when scrubbing exists; another candidate is H2S(g), but it can be affected by reactions with aqueous ferrous iron. In contrast, scrubbing by water will prevent significant SO2(g) and most HCl(g) emissions until dry pathways are established, except for moderate HCl(g) degassing from pH 100 t/d (tons per day) of SO2(g) in addition to CO2(g) and H2S(g) should be taken as a criterion of magma intrusion. Finally, the modeling suggests that the interpretation of gas-ratio data requires a case-by-case evaluation since ratio changes can often be produced by several mechanisms; nevertheless, several gas ratios may provide useful indices for monitoring the drying out of gas pathways. Published by Elsevier Science B.V.

  5. Integrated Microfluidic Gas Sensors for Water Monitoring

    NASA Technical Reports Server (NTRS)

    Zhu, L.; Sniadecki, N.; DeVoe, D. L.; Beamesderfer, M.; Semancik, S.; DeVoe, D. L.

    2003-01-01

    A silicon-based microhotplate tin oxide (SnO2) gas sensor integrated into a polymer-based microfluidic system for monitoring of contaminants in water systems is presented. This device is designed to sample a water source, control the sample vapor pressure within a microchannel using integrated resistive heaters, and direct the vapor past the integrated gas sensor for analysis. The sensor platform takes advantage of novel technology allowing direct integration of discrete silicon chips into a larger polymer microfluidic substrate, including seamless fluidic and electrical interconnects between the substrate and silicon chip.

  6. Insights into aerosol formation chemistry from comprehensive gas-phase precursor measurement in the TRAPOZ chamber experiments; an overview

    NASA Astrophysics Data System (ADS)

    Carr, Timo; Wyche, Kevin; Monks, Paul S.; Camredon, Marie; Alam, Mohammed S.; Bloss, William J.; Rickard, Andrew R.

    2010-05-01

    Aerosols have a profound affect on the environment on local, regional and even global levels, with impacts including adverse health effects, (Alfarra, Paulsen et al. 2006) visibility reduction, cloud formation, direct radiative forcing (Charlson, Schwartz et al. 1992) and an important role in influencing the climate due to their contribution to important atmospheric processes (Baltensperger, Kalberer et al. 2005; Alfarra, Paulsen et al. 2006). The Total Radical Production from the OZonolysis of alkenes (TRAPOZ) project was used to study the gas phase and radical chemistry along with secondary organic aerosol (SOA) formation for a number of different alkenes and terpenes. In order to better the scientific knowledge regarding the oxidation mechanisms of terpene and alkene species along with radical and SOA formation, the experiments were conducted under varying conditions controlled and monitored by the EUropean PHOto REactor (EUPHORE) simulation chamber in Valencia, Spain. A vast number of instruments enabled a detailed examination of the chemistry within oxidation of each precursor. However the work here will focus on the results obtained from the University of Leicester Chemical Ionisation Reaction Time-of-Flight Mass Spectrometer (CIR-TOF-MS). With regard to the gas phase chemistry an analysis of the degradation of the precursor Volatile Organic Compounds (VOCs) and evolution of certain gas phase species in each experiment has been presented and discussed.

  7. Precise and high-speed control of partial pressures of multiple gas species in plasma process chamber using pulse-controlled gas injection

    SciTech Connect

    Morishita, Sadaharu; Goto, Tetsuya; Nagase, Masaaki; Ohmi, Tadahiro

    2009-05-15

    Multiprocesses in a single plasma process chamber with high throughput require precise, sequential, high-speed alteration of partial pressures of multiple gas species. A conventional gas-distribution system cannot realize this because the system seriously overshoots gas pressure immediately following valve operation. Furthermore, chamber volume and conductance of gas piping between the system and chamber should both be considered because they delay the stabilizing time of gas pressure. Therefore, the authors proposed a new gas-distribution system without overshoot by controlling gas flow rate based on pressure measurement, as well as a method of pulse-controlled gas injection immediately following valve operation. Time variation of measured partial pressure agrees well with a calculation based on an equivalent-circuit model that represents the chamber and gas piping between the system and chamber. Using pulse-controlled gas injection, the stabilizing time can be reduced drastically to 0.6 s for HBr added to pure Ar plasma, and 0.7 s for O{sub 2} added to Ar/HBr plasma; without the pulse control, the stabilizing times are 3 and 7 s, respectively. In the O{sub 2} addition case, rapid stabilization can be achieved during the period of line/space pattern etching of poly-Si on a thin SiO{sub 2} film. This occurs without anomalous etching of the underlying SiO{sub 2} film or the Si substrate near the sidewall, thus obtaining a wide process margin with high throughput.

  8. A fast position sensitive microstrip-gas-chamber detector at high count rate operation

    NASA Astrophysics Data System (ADS)

    Dolbnya, I. P.; Alberda, H.; Hartjes, F. G.; Udo, F.; Bakker, R. E.; Konijnenburg, M.; Homan, E.; Cerjak, I.; Goedtkindt, P.; Bras, W.

    2002-11-01

    Testing of a newly developed position sensitive high count rate microstrip gas chamber (MSGC) detector at high count rate operation has been carried out at the Dutch-Belgian x-ray scattering beamline at the European Synchrotron Radiation Facility (Grenoble, France) with a high intensity x-ray beam. The measurements show local count rate capabilities up to approx4.5 x105 counts/s/channel. Experimental data taken with this detector are also shown. These tests show that both time resolution down to 1.5 ms/frame and a reliable operation at high counting rates can be achieved.

  9. Two-chamber hydrogen generation and application: access to pressurized deuterium gas.

    PubMed

    Modvig, Amalie; Andersen, Thomas L; Taaning, Rolf H; Lindhardt, Anders T; Skrydstrup, Troels

    2014-06-20

    Hydrogen and deuterium gas were produced and directly applied in a two-chamber system. These gaseous reagents were generated by the simple reaction of metallic zinc with HCl in water for H2 and DCl in deuterated water for D2. The setup proved efficient in classical Pd-catalyzed reductions of ketones, alkynes, alkenes, etc. in near-quantitative yields. The method was extended to the synthesis and isotope labeling of quinoline and 1,2,3,4-tetrahydroquinoline derivatives. Finally, CX-546 and Olaparib underwent efficient Ir-catalyzed hydrogen isotope exchange reactions. PMID:24870212

  10. Monitoring gas reservoirs by seismic interferometry

    NASA Astrophysics Data System (ADS)

    Grigoli, Francesco; Cesca, Simone; Sens-Schoenfelder, Christoph; Priolo, Enrico

    2014-05-01

    Ambient seismic noise can be used to image spatial anomalies in the subsurface, without the need of recordings from seismic sources, such as earthquakes or explosions. Furthermore, the temporal variation of ambient seismic noise's can be used to infer temporal changes of the seismic velocities in the investigated medium. Such temporal variations can reflect changes of several physical properties/conditions in the medium. For example, they may be consequence of stress changes, variation of hydrogeological parameters, pore pressure and saturation changes due to fluid injection or extraction. Passive image interferometry allows to continuously monitor small temporal changes of seismic velocities in the subsurface, making it a suitable tool to monitor time-variant systems such as oil and gas reservoirs or volcanic environments. The technique does not require recordings from seismic sources in the classical sense, but is based on the processing of noise records. Moreover, it requires only data from one or two seismic stations, their locations constraining the sampled target area. Here we apply passive image interferometry to monitor a gas storage reservoir in northern Italy. The Collalto field (Northern Italy) is a depleted gas reservoir located at 1500 m depth, now used as a gas storage facility. The reservoir experience a significant temporal variation in the amount of stored gas: the injection phases mainly occur in the summer, while the extraction take place mostly in winter. In order to monitor induced seismicity related to gas storage operations, a seismic network (the Collalto Seismic Network) has been deployed in 2011. The Collalto Seismic Network is composed by 10 broadband stations, deployed within an area of about 20 km x 20 km, and provides high-quality continuous data since January 1st, 2012. In this work we present preliminary results from ambient noise interferometry using a two-months sample of continuous seismic data, i.e. from October 1st, 2012, to the

  11. Incidence and Outcomes of Anterior Chamber Gas Bubble during Femtosecond Flap Creation for Laser-Assisted In Situ Keratomileusis.

    PubMed

    Rush, Sloan W; Cofoid, Philip; Rush, Ryan B

    2015-01-01

    Purpose. To report the incidence and outcomes of anterior chamber gas bubble formation during femtosecond laser flap creation for laser-assisted in situ keratomileusis (LASIK). Methods. The charts of 2,886 consecutive eyes that underwent femtosecond LASIK from May 2011 through August 2014 were retrospectively reviewed. The incidence, preoperative characteristics, intraoperative details, and postoperative outcomes were analyzed in subjects developing anterior chamber gas bubble formation during the procedure. Results. A total of 4 cases (0.14%) developed anterior chamber gas bubble formation during femtosecond laser flap creation. In all four cases, the excimer laser was unable to successfully track the pupil immediately following the anterior chamber bubble formation, temporarily postponing the completion of the procedure. There was an ethnicity predilection of anterior chamber gas formation toward Asians (p = 0.0055). An uncorrected visual acuity of 20/20 was ultimately achieved in all four cases without further complications. Conclusions. Anterior chamber gas bubble formation during femtosecond laser flap creation for LASIK is an uncommon event that typically results in a delay in treatment completion; nevertheless, it does influence final positive visual outcome. PMID:25954511

  12. Incidence and Outcomes of Anterior Chamber Gas Bubble during Femtosecond Flap Creation for Laser-Assisted In Situ Keratomileusis

    PubMed Central

    Rush, Sloan W.; Cofoid, Philip; Rush, Ryan B.

    2015-01-01

    Purpose. To report the incidence and outcomes of anterior chamber gas bubble formation during femtosecond laser flap creation for laser-assisted in situ keratomileusis (LASIK). Methods. The charts of 2,886 consecutive eyes that underwent femtosecond LASIK from May 2011 through August 2014 were retrospectively reviewed. The incidence, preoperative characteristics, intraoperative details, and postoperative outcomes were analyzed in subjects developing anterior chamber gas bubble formation during the procedure. Results. A total of 4 cases (0.14%) developed anterior chamber gas bubble formation during femtosecond laser flap creation. In all four cases, the excimer laser was unable to successfully track the pupil immediately following the anterior chamber bubble formation, temporarily postponing the completion of the procedure. There was an ethnicity predilection of anterior chamber gas formation toward Asians (p = 0.0055). An uncorrected visual acuity of 20/20 was ultimately achieved in all four cases without further complications. Conclusions. Anterior chamber gas bubble formation during femtosecond laser flap creation for LASIK is an uncommon event that typically results in a delay in treatment completion; nevertheless, it does influence final positive visual outcome. PMID:25954511

  13. Strip Ionization Chamber as Beam Monitor in the Proton Therapy Eye Treatment

    NASA Astrophysics Data System (ADS)

    Marchetto, F.; Cirio, R.; Garella, M. A.; Giordanengo, S.; Boriano, A.; Givehchi, N.; La Rosa, A.; Peroni, C.; Donetti, M.; Bourhaleb, F.; Pitta', G.; Cirrone, G. A. P.; Cuttone, G.; Raffaele, L.; Sabini, M. G.; Valastro, L.

    2006-04-01

    Since spring 2002, ocular pathologies have been treated in Catania at the Centro di AdroTerapia e Applicazioni Nucleari Avanzate (CATANA) within a collaboration between INFN Laboratori Nazionali del Sud (LNS), Physics Department, Ophthalmology Institute, Radiology Institute of the Catania University and CSFNSM Catania. A beam line from a 62 MeV Superconducting Cyclotron is used to treat shallow tumors. The beam is conformed to the tumor shape with a passive delivery system. A detector system has been developed in collaboration with INFN-Torino to be used as real time beam monitor. The detector, placed upstream of the patient collimator, consists of two parallel plate ionization chambers with the anode segmented in strips. Each anode is made of 0.5 mm-wide 256 strips corresponding to (12.8 × 12.8) cm2 sensitive area. With the two strip ionization chambers one can measure the relevant beam parameters during treatment to probe both asymmetry and flatness. In the test carried out at CATANA the detector has been used under different and extreme beam conditions. Preliminary results are given for profiles and skewness, together with a comparison with reference detectors.

  14. Measurement of photon flux with a miniature gas ionization chamber in a Material Testing Reactor

    NASA Astrophysics Data System (ADS)

    Fourmentel, D.; Filliatre, P.; Villard, J. F.; Lyoussi, A.; Reynard-Carette, C.; Carcreff, H.

    2013-10-01

    Nuclear heating measurements in Material Testing Reactors (MTR) are crucial for the design of the experimental devices and the prediction of the temperature of the hosted samples. Nuclear heating in MTR materials (except fuel) is mainly due to the energy deposition by the photon flux. Therefore, the photon flux is a key input parameter for the computer codes which simulate nuclear heating and temperature reached by samples/devices under irradiation. In the Jules Horowitz MTR under construction at the CEA Cadarache, the maximal expected nuclear heating levels will be about 15 to 18 W g-1 and it will be necessary to assess this parameter with the best accuracy. An experiment was performed at the OSIRIS reactor to combine neutron flux, photon flux and nuclear heating measurements to improve the knowledge of the nuclear heating in MTR. There are few appropriate sensors for selective measurement of the photon flux in MTR even if studies and developments are ongoing. An experiment, called CARMEN-1, was conducted at the OSIRIS MTR and we used in particular a gas ionization chamber based on miniature fission chamber design to measure the photon flux. In this paper, we detail Monte-Carlo simulations to analyze the photon fluxes with ionization chamber measurements and we compare the photon flux calculations to the nuclear heating measurements. These results show a good accordance between photon flux measurements and nuclear heating measurement and allow improving the knowledge of these parameters.

  15. High pressure multiwire proportional and gas microstrip chambers for medical radiology

    NASA Astrophysics Data System (ADS)

    Babichev, E. A.; Baru, S. E.; Khabakhpashev, A. G.; Kolachev, G. M.; Neustroev, V. V.; Pestov, Yu. N.; Ponomarev, O. A.; Savinov, G. M.; Shekhtman, L. I.; Martinez-Davalos, A.; Speller, R. D.; Miller, D. J.

    1995-02-01

    Application of MultiWire Proportional Chambers (MWPC) and MicroStrip Gas Chambers (MSGC) in medical radiography is discussed. These detectors are capable of detecting X-rays in counting mode with high efficiency, thus giving essential dose reduction compared to film/screen techniques. This was demonstrated on several Digital Radiographic Devices (DRD) with one-dimensional MWPC and scanning in the orthogonal direction. Effective pixel sizes of 1 mm and 0.5 mm for different devices with highly parallel readout systems has been achieved. The counting rate capability of DRDs is ˜ 500 kHz/pixel, which is enough to get high statistics of X-rays with a short exposure. Dose saving factors from 1 to 2 orders of magnitude for several common examinations were demonstrated. Further development of this approach can be made with MSGC which reproduce operation of MWPC in a much smaller scale. First tests of prototype chambers with 200 μm pitch of strips at high pressure have shown the possibility to reach a gain of ˜ 10 4 in a 6 bar Xe mixture. A proper choice of substrate material permits one to avoid charging problems at high fluxes. These features allow, one to build a counting device with 0.2 mm pixels for the detection of X-rays of 20-60 keV.

  16. 30 CFR 70.1900 - Exhaust Gas Monitoring.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 30 Mineral Resources 1 2012-07-01 2012-07-01 false Exhaust Gas Monitoring. 70.1900 Section 70.1900 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR COAL MINE SAFETY AND HEALTH MANDATORY HEALTH STANDARDS-UNDERGROUND COAL MINES DIESEL EXHAUST GAS MONITORING § 70.1900 Exhaust Gas Monitoring. (a) During...

  17. 30 CFR 70.1900 - Exhaust Gas Monitoring.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 30 Mineral Resources 1 2013-07-01 2013-07-01 false Exhaust Gas Monitoring. 70.1900 Section 70.1900 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR COAL MINE SAFETY AND HEALTH MANDATORY HEALTH STANDARDS-UNDERGROUND COAL MINES Diesel Exhaust Gas Monitoring § 70.1900 Exhaust Gas Monitoring. (a) During...

  18. A Ground Deformation Monitoring Approach to Understanding Magma Chamber Systems and Eruptive Cycles of Mount Cameroon

    NASA Astrophysics Data System (ADS)

    Riley, S.; Clarke, A.

    2005-05-01

    Mount Cameroon is a 13,400ft basanite volcano on the passive margin of West Africa. It has erupted seven times in the past century making it one of the most active volcanoes in Africa. Most recently Mount Cameroon erupted in 1999 and 2000 first issuing strombolian explosions from vents near the summit, and later erupting effusively from a fissure running southwest from the summit (Suh et al., 2003). Prior to 2004, the only monitoring equipment on Mount Cameroon was a small seismometer network installed following the 1982 eruption. By 1999 only a single seismometer in the network was functional. Seismic activity did not rise above background levels until the few days immediately preceding the eruption. In an effort to raise awareness of the volcano's condition and provide a more efficient warning of impending eruptions we have begun constructing a ground deformation network on Mount Cameroon. The new network currently consists of two Applied Geomechanics 711-2A(4X) biaxial tiltmeters capable of resolving 0.1 microradians of tilt. One station is located approximately 500 m from the 2000 summit vent, and the other is approximately 1km away from the central fissure approximately 5km southwest of the 2000 summit vent. Three primary processes could precede eruptions at Mt. Cameroon, offering the opportunity for detection and prediction by our network. These processes are magma chamber pressurization, magma ascent via a central conduit, and/or propagation of magma along the central fissure. Magma chamber location, if a significant chamber exists, is poorly constrained, however, previous petrologic studies on Mount Cameroon (Suh et al., 2003; Fitton et al., 1983) suggest Mount Cameroon magmas originate at a depth less than 40km. Published seismic data (Ambeh, 1989) contains evidence of magmatic activity and possible chambers at depths ranging from 10km to 70km. Preliminary calculations using a simple Mogi model suggest deformation caused by pressurization of a large

  19. Experimental investigation of entropy waves during unstable combustion in the chamber of a gas turbine engine

    SciTech Connect

    Doroshenko, V.E.; Sil'verstov, V.M.

    1982-07-01

    This study attempts to detect entropy waves which have been suggested as a factor in the tense pressure vibrations caused during unstable combustions. A diagram of the test apparatus, burner, choke, transducer (to record vibration), amplifier, and spectrum analyzer are detailed. Temperature oscillations, the phase of oscillations, are measured by specified device. The test is based on the laws of Wien and Kirchoff which makes it possible to establish a relation between brightness and true temperature. By this measurement of the oscillations of gas temperatures it is established that at the outlet of a single-burner section of the combustion chamber of a gas turbine engine in the unstable combustion regime, there exist intense non-isentropic temperature oscillations of considerable amplitude. These are evidence of the presence of entropy waves.

  20. Apparatus and method for monitoring of gas having stable isotopes

    DOEpatents

    Clegg, Samuel M; Fessenden-Rahn, Julianna E

    2013-03-05

    Gas having stable isotopes is monitored continuously by using a system that sends a modulated laser beam to the gas and collects and transmits the light not absorbed by the gas to a detector. Gas from geological storage, or from the atmosphere can be monitored continuously without collecting samples and transporting them to a lab.

  1. Neutral gas desorption and photoelectric emission from aluminum alloy vacuum chambers exposed to synchrotron radiation

    SciTech Connect

    Groebner, O.; Mathewson, A.G.; Strubin, P.; Alge, E.; Souchet, R.

    1989-03-01

    In an aluminum alloy vacuum chamber exposed to synchrotron radiation, the photoelectron currents produced were measured with the photons incident at low angles on the side wall and compared with normal incidence. The calculated photocurrents for normal incidence, using published values of the photoyield for oxidized Al, agree to within 15% with the measured values. Differences in the photocurrent dependence on photon spectrum at normal and glancing incidence were attributed to low-energy photons being totally reflected and hence producing no photoelectrons. It was established that, at glancing angles of incidence down to 11 mrad, a substantial: more than 20%: fraction of the synchrotron radiation is scattered around the vacuum chamber from the initial point of impact. During exposure to synchrotron radiation, the gases desorbed were H/sub 2/, CO, CO/sub 2/, and CH/sub 4/. The similar shapes of the dependence of the gas desorption and the photoelectron currents on the photon spectrum suggested that it is mainly the photoelectrons that are contributing to the desorption. It was estimated that electrons of 60 eV would produce the same gas desorption as synchrotron radiation with a critical energy of 3 keV.

  2. Restoring contaminated wires, removing gas contaminants, and aging studies of drift tube chambers

    NASA Astrophysics Data System (ADS)

    Marshall, Thomas

    2003-12-01

    The original muon detection system of the Fermilab D0 colliding beam experiment contained 12,000 drift cells 10 cm×5 cm in cross-section and up to 580 cm in length. The gas mixture used was Ar/CF 4/CO 2 (90:6:4). There was one recycling gas system for all the chambers. During the first year of operation, it was discovered that inefficient cells, all in regions of high radiation, had a contaminating shell of crud coating their wires. The source of the contaminant was outgassing of the cathode pads, which were made from a laminate of fiberglass and epoxy/polyester resin, with a copper cladding on one surface. The vapor formed a brittle sheath on the wires, but only in regions of high current discharge due to radiation from the accelerator and colliding beams. A method for cleaning wires in place was devised. By heating the wire quickly to a temperature close to the melting temperature of gold, the sheath was ripped to shreds and blown away. The procedure for "zapping" wires and for removing the contaminating vapor is presented. The upgraded D0 experiment now uses Iarocci-type mini-drift tubes for the forward muon system. The results of aging tests for these chambers are also presented.

  3. Evaluation of resistive-plate-chamber-based TOF-PET applied to in-beam particle therapy monitoring

    NASA Astrophysics Data System (ADS)

    Torres-Espallardo, I.; Diblen, F.; Rohling, H.; Solevi, P.; Gillam, J.; Watts, D.; España, S.; Vandenberghe, S.; Fiedler, F.; Rafecas, M.

    2015-05-01

    Particle therapy is a highly conformal radiotherapy technique which reduces the dose deposited to the surrounding normal tissues. In order to fully exploit its advantages, treatment monitoring is necessary to minimize uncertainties related to the dose delivery. Up to now, the only clinically feasible technique for the monitoring of therapeutic irradiation with particle beams is Positron Emission Tomography (PET). In this work we have compared a Resistive Plate Chamber (RPC)-based PET scanner with a scintillation-crystal-based PET scanner for this application. In general, the main advantages of the RPC-PET system are its excellent timing resolution, low cost, and the possibility of building large area systems. We simulated a partial-ring scanner based on an RPC prototype under construction within the Fondazione per Adroterapia Oncologica (TERA). For comparison with the crystal-based PET scanner we have chosen the geometry of a commercially available PET scanner, the Philips Gemini TF. The coincidence time resolution used in the simulations takes into account the current achievable values as well as expected improvements of both technologies. Several scenarios (including patient data) have been simulated to evaluate the performance of different scanners. Initial results have shown that the low sensitivity of the RPC hampers its application to hadron-beam monitoring, which has an intrinsically low positron yield compared to diagnostic PET. In addition, for in-beam PET there is a further data loss due to the partial ring configuration. In order to improve the performance of the RPC-based scanner, an improved version of the RPC detector (modifying the thickness of the gas and glass layers), providing a larger sensitivity, has been simulated and compared with an axially extended version of the crystal-based device. The improved version of the RPC shows better performance than the prototype, but the extended version of the crystal-based PET outperforms all other options.

  4. Feasibility study of monitoring of plasma etching chamber conditions using superimposed high-frequency signals on rf power transmission line.

    PubMed

    Kasashima, Y; Uesugi, F

    2015-10-01

    An in situ monitoring system that can detect changes in the conditions of a plasma etching chamber has been developed. In the system, low-intensity high-frequency signals are superimposed on the rf power transmission line used for generating plasma. The system measures reflected high-frequency signals and detects the change in their frequency characteristics. The results indicate that the system detects the changes in the conditions in etching chambers caused by the changes in the electrode gap and the inner wall condition and demonstrate the effectiveness of the system. The system can easily be retrofitted to mass-production equipment and it can be used with or without plasma discharge. Therefore, our system is suitable for in situ monitoring of mass-production plasma etching chambers. The system is expected to contribute to development of predictive maintenance, which monitors films deposited on the inner wall of the chamber and prevents equipment faults caused by misalignment of chamber parts in mass-production equipment. PMID:26520984

  5. The Impacts of Changes in Snowfall on Soil Greenhouse Gas Emissions Using an Automated Chamber System

    NASA Astrophysics Data System (ADS)

    Ruan, L.; Kahmark, K.; Robertson, G.

    2012-12-01

    Snow cover has decreased in many regions of the northern hemisphere and is projected to decrease further in most. The reduced snow cover may enhance soil freezing and increase the depth of frost. The frequency of freeze-thaw cycles is likely to increase due to the reduction of snowpack thickness. Freeze and thaw cycles can strongly affect soil C and N dynamics. The pulses of N2O and CO2 emissions from soil after thawing have been reported in various studies. However, most studies were based on the controlled laboratory conditions or low resolution static chamber methods in situ. Near-continuous automated chambers provide the temporal resolution needed for capturing short-lived pulses of greenhouse gases after intermittent melting events. We investigated the winter and spring response of soil greenhouse gas emissions (CO2, CH4 and N2O) to changes of snow depth using an automated chamber system. This study was established in 2010 at the Kellogg Biological Station (KBS) in southwest Michigan. The plot was no till rotational (corn-soybean-wheat) cropland, most recently in corn. The experiment was a completely randomized design (CRD) with three levels of snow depth: ambient, double, and no snow. Each level had four replicates. Twelve automated chambers were randomly assigned to treatments and greenhouse gas fluxes measured 4 times per day in each plot. There were more freeze-thaw cycles in the no snow treatment than in the ambient and double snow treatments. Soil temperature at 5 cm depth was more variable in the no snow treatment than in the ambient and double snow treatments. CH4 fluxes were uniformly low with no significant difference across three treatments. CO2 showed expected seasonal changes with the highest emission in spring and lowest emissions through the winter. N2O peaks were higher in spring due to freeze thaw effects and cumulative N2O fluxes were substantially higher in the no snow treatment than in the ambient and double snow treatments.

  6. Inherently safe passive gas monitoring system

    DOEpatents

    Cordaro, Joseph V.; Bellamy, John Stephen; Shuler, James M.; Shull, Davis J.; Leduc, Daniel R.

    2016-09-06

    Generally, the present disclosure is directed to gas monitoring systems that use inductive power transfer to safely power an electrically passive device included within a nuclear material storage container. In particular, the electrically passive device can include an inductive power receiver for receiving inductive power transfer through a wall of the nuclear material storage container. The power received by the inductive power receiver can be used to power one or more sensors included in the device. Thus, the device is not required to include active power generation components such as, for example, a battery, that increase the risk of a spark igniting flammable gases within the container.

  7. Air Monitoring for Hazardous Gas Detection

    NASA Technical Reports Server (NTRS)

    Arkin, C. Richard; Griffin, Timothy P.; Adams, Frederick W.; Naylor, Guy; Haskell, William; Floyd, David; Curley, Charles; Follistein, Duke W.

    2004-01-01

    The Hazardous Gas Detection Lab (HGDL) at Kennedy Space Center is involved in the design and development of instrumentation that can detect and quantify various hazardous gases. Traditionally these systems are designed for leak detection of the cryogenic gases used for the propulsion of the Shuttle and other vehicles. Mass spectrometers are the basis of these systems, which provide excellent quantitation, sensitivity, selectivity, response times and detection limits. A Table lists common gases monitored for aerospace applications. The first five gases, hydrogen, helium, nitrogen, oxygen, and argon are historically the focus of the HGDL.

  8. The N.A.C.A. Combustion Chamber Gas-sampling Valve and Some Preliminary Test Results

    NASA Technical Reports Server (NTRS)

    Spanogle, J A; Buckley, E C

    1933-01-01

    A gas sampling valve of the inertia-operated type was designed for procuring samples of the gases in the combustion chamber of internal combustion engines at identical points in successive cycles so that the analysis of the gas samples thus procured may aid in the study of the process of combustion. The operation of the valve is described. The valve was used to investigate the CO2 content of gases taken from the quiescent combustion chamber of a high speed compression-ignition engine when operating with two different multiple-orifice fuel injection nozzles. An analysis of the gas samples thus obtained shows that the state of quiescence in the combustion chamber is maintained during the combustion of the fuel.

  9. Method and apparatus for monitoring mercury emissions

    DOEpatents

    Durham, Michael D.; Schlager, Richard J.; Sappey, Andrew D.; Sagan, Francis J.; Marmaro, Roger W.; Wilson, Kevin G.

    1997-01-01

    A mercury monitoring device that continuously monitors the total mercury concentration in a gas. The device uses the same chamber for converting speciated mercury into elemental mercury and for measurement of the mercury in the chamber by radiation absorption techniques. The interior of the chamber is resistant to the absorption of speciated and elemental mercury at the operating temperature of the chamber.

  10. Method and apparatus for monitoring mercury emissions

    DOEpatents

    Durham, M.D.; Schlager, R.J.; Sappey, A.D.; Sagan, F.J.; Marmaro, R.W.; Wilson, K.G.

    1997-10-21

    A mercury monitoring device that continuously monitors the total mercury concentration in a gas. The device uses the same chamber for converting speciated mercury into elemental mercury and for measurement of the mercury in the chamber by radiation absorption techniques. The interior of the chamber is resistant to the absorption of speciated and elemental mercury at the operating temperature of the chamber. 15 figs.

  11. Arterial gas embolism during pressure tolerance testing in a hyperbaric chamber: a report of two cases.

    PubMed

    Buschmann, D Kim

    2010-12-01

    This is a report of two cases of arterial gas embolism (AGE) occurring during the course of routine pressure tolerance testing (PTT) of Canadian Forces divers in a dry hyperbaric chamber. PTT is used by many military organizations as a means to determine whether divers can sustain a hyperbaric challenge similar to that to which they will be exposed during their diving duties. Problems arising from such testing are usually limited to issues of equalization and minor otic barotraumas. Incidents of AGE resulting from hyperbaric chamber exposures in general are very unusual. The incidents reported here are the first such cases arising in military divers during PTT to be reported in the extant literature. In one case a potential precipitating pulmonary lesion was identified during post-event chest imaging. In the other case, while presenting with all the usual hallmarks of an AGE, no predisposing pulmonary lesion was identified. Ascent rates were within the limits considered acceptable by the Canadian Forces for PTT. The cases are useful in examining the pathophysiologic mechanisms underlying pulmonary barotrauma and AGE, and raise questions as to the appropriate screening procedures for military divers in this regard. PMID:21197859

  12. Study of deposit associated with discharge in micro-pixel gas chamber

    NASA Astrophysics Data System (ADS)

    Homma, Y.; Ochi, A.; Moriya, K.; Matsuda, S.; Yoshida, K.; Kobayashi, S.

    2009-02-01

    We found some deposits associated with discharge on dielectric (polyimide) substrates in "Micro-Pixel Gas Chambers" ( μ-PIC) operating with Ar/C2H6 90/10. Secondary electron images taken with a scanning electron microscope (SEM) revealed that they were a conductive material. Auger electron spectroscopy clearly showed that their main component was carbon (98%). Their origin was clarified using spark tests in which a single pixel was sparked a specific number of times. Secondary electron images clearly showed that discharge occurred in the narrow gaps between the electrodes. With a Ar/C2H6 50/50 gas mixture, the amount of carbon deposited depended on the number of sparks. The drop in the applied voltage after the test depended on the number of sparks. With pure N2 gas, no deposits were clearly found, however, a decrease in the applied voltage after the tests was observed. This can be attributed to carbonization of the polyimide surface. Although the SEM images did not show clear proof of this, this carbonization could contribute much less than the ethane dissociation.

  13. A Concept for a Low Pressure Noble Gas Fill Intervention in the IFE Fusion Test Facility (FTF) Target Chamber

    SciTech Connect

    Gentile, C. A.; Blanchard, W. R.; Kozub, T. A.; Aristova, M.; McGahan, C.; Natta, S.; Pagdon, K.; Zelenty, J.

    2010-01-14

    An engineering evaluation has been initiated to investigate conceptual engineering methods for implementing a viable gas shield strategy in the Fusion Test Facility (FTF) target chamber. The employment of a low pressure noble gas in the target chamber to thermalize energetic helium ions prior to interaction with the wall could dramatically increase the useful life of the first wall in the FTF reactor1. For the purpose of providing flexibility, two target chamber configurations are addressed: a five meter radius sphere and a ten meter radius sphere. Experimental studies at Nike have indicated that a low pressure, ambient gas resident in the target chamber during laser pulsing does not appear to impair the ability of laser light from illuminating targets2. In addition, current investigations into delivering, maintaining, and processing low pressure gas appear to be viable with slight modification to current pumping and plasma exhaust processing technologies3,4. Employment of a gas fill solution for protecting the dry wall target chamber in the FTF may reduce, or possibly eliminate the need for other attenuating technologies designed for keeping He ions from implanting in first wall structures and components. The gas fill concept appears to provide an effective means of extending the life of the first wall while employing mostly commercial off the shelf (COTS) technologies. Although a gas fill configuration may provide a methodology for attenuating damage inflicted on chamber surfaces, issues associated with target injection need to be further analyzed to ensure that the gas fill concept is viable in the integrated FTF design5. In the proposed system, the ambient noble gas is heated via the energetic helium ions produced by target detonation. The gas is subsequently cooled by the chamber wall to approximately 800oC, removed from the chamber, and processed by the chamber gas processing system (CGPS). In an optimized scenario of the above stated concept, the chamber

  14. Gamma-ray astronomy using a high pressure gas scintillation drift chamber with a waveshifting fiber readout

    NASA Technical Reports Server (NTRS)

    Wilkerson, J.; Edberg, T. K.; Parsons, A.; Sadoulet, B.; Weiss, S.; Smith, G.

    1992-01-01

    We describe a balloon-borne hard X-ray telescope called SIGHT (Scintillation Imaging Gas-filled Hard X-ray Telescope). SIGHT is a high sensitivity, good energy resolution instrument that images in the 30 to 300 keV region. We discuss the development of a large area, 20 atmosphere, position sensitive xenon gas scintillation drift chamber which is the gamma-ray detector at the heart of the telescope package. Results of the development of the novel waveshifting fiber readout for this chamber are presented.

  15. Microminiature thermocouple monitors own installation

    NASA Technical Reports Server (NTRS)

    Garrett, A. J.; Sellers, J. P., Jr.

    1966-01-01

    Microminiature thermocouple makes precision gas sidewall temperature readings inside large thrust chambers. It is installed by a technique whereby the sensor monitors its own installation to insure against thermal damage to the thermocouple and ensure minimum disturbance to chamber surfaces.

  16. Magmatic gas scrubbing: implications for volcano monitoring

    NASA Astrophysics Data System (ADS)

    Symonds, R. B.; Gerlach, T. M.; Reed, M. H.

    2001-08-01

    Despite the abundance of SO 2(g) in magmatic gases, precursory increases in magmatic SO 2(g) are not always observed prior to volcanic eruption, probably because many terrestrial volcanoes contain abundant groundwater or surface water that scrubs magmatic gases until a dry pathway to the atmosphere is established. To better understand scrubbing and its implications for volcano monitoring, we model thermochemically the reaction of magmatic gases with water. First, we inject a 915°C magmatic gas from Merapi volcano into 25°C air-saturated water (ASW) over a wide range of gas/water mass ratios from 0.0002 to 100 and at a total pressure of 0.1 MPa. Then we model closed-system cooling of the magmatic gas, magmatic gas-ASW mixing at 5.0 MPa, runs with varied temperature and composition of the ASW, a case with a wide range of magmatic-gas compositions, and a reaction of a magmatic gas-ASW mixture with rock. The modeling predicts gas and water compositions, and, in one case, alteration assemblages for a wide range of scrubbing conditions; these results can be compared directly with samples from degassing volcanoes. The modeling suggests that CO 2(g) is the main species to monitor when scrubbing exists; another candidate is H 2S (g), but it can be affected by reactions with aqueous ferrous iron. In contrast, scrubbing by water will prevent significant SO 2(g) and most HCl (g) emissions until dry pathways are established, except for moderate HCl (g) degassing from pH<0.5 hydrothermal waters. Furthermore, it appears that scrubbing will prevent much, if any, SO 2(g) degassing from long-resident boiling hydrothermal systems. Several processes can also decrease or increase H 2(g) emissions during scrubbing making H 2(g) a poor choice to detect changes in magma degassing. We applied the model results to interpret field observations and emission rate data from four eruptions: (1) Crater Peak on Mount Spurr (1992) where, except for a short post-eruptive period, scrubbing appears

  17. Real-time monitoring of benzene, toluene, and p-xylene in a photoreaction chamber with a tunable mid-infrared laser and ultraviolet differential optical absorption spectroscopy.

    PubMed

    Parsons, Matthew T; Sydoryk, Ihor; Lim, Alan; McIntyre, Thomas J; Tulip, John; Jäger, Wolfgang; McDonald, Karen

    2011-02-01

    We describe the implementation of a mid-infrared laser-based trace gas sensor with a photoreaction chamber, used for reproducing chemical transformations of benzene, toluene, and p-xylene (BTX) gases that may occur in the atmosphere. The system performance was assessed in the presence of photoreaction products including aerosol particles. A mid-infrared external cavity quantum cascade laser (EC-QCL)-tunable from 9.41-9.88 μm (1012-1063 cm(-1))-was used to monitor gas phase concentrations of BTX simultaneously and in real time during chemical processing of these compounds with hydroxyl radicals in a photoreaction chamber. Results are compared to concurrent measurements using ultraviolet differential optical absorption spectroscopy (UV DOAS). The EC-QCL based system provides quantitation limits of approximately 200, 200, and 600 parts in 10(9) (ppb) for benzene, toluene, and p-xylene, respectively, which represents a significant improvement over our previous work with this laser system. Correspondingly, we observe the best agreement between the EC-QCL measurements and the UV DOAS measurements with benzene, followed by toluene, then p-xylene. Although BTX gas-detection limits are not as low for the EC-QCL system as for UV DOAS, an unidentified by-product of the photoreactions was observed with the EC-QCL, but not with the UV DOAS system. PMID:21283225

  18. Method of monitoring photoactive organic molecules in-situ during gas-phase deposition of the photoactive organic molecules

    SciTech Connect

    Forrest, Stephen R.; Vartanian, Garen; Rolin, Cedric

    2015-06-23

    A method for in-situ monitoring of gas-phase photoactive organic molecules in real time while depositing a film of the photoactive organic molecules on a substrate in a processing chamber for depositing the film includes irradiating the gas-phase photoactive organic molecules in the processing chamber with a radiation from a radiation source in-situ while depositing the film of the one or more organic materials and measuring the intensity of the resulting photoluminescence emission from the organic material. One or more processing parameters associated with the deposition process can be determined from the photoluminescence intensity data in real time providing useful feedback on the deposition process.

  19. A Novel Temperature Monitoring Sensor for Gas-Based Detectors in Large HEP Experiments

    NASA Astrophysics Data System (ADS)

    Benussi, L.; Bianco, S.; Caponero, M. A.; Colafranceschi, S.; Ferrini, M.; Felli, F.; Passamonti, L.; Pierluigi, D.; Polimadei, A.; Russo, A.; Saviano, G.; Vendittozzi, C.

    Gaseous detectors are commonly used in HEP (High Energy Physics) experiments to reconstruct the track of elementary particles. They are often made by a very large number of chambers with relatively small individual volume, arranged in thick layers placed approximately all around the vertex of the experiment in order to detect elementary particles produced in any direction. The large volume of gas inside the detector must be monitored for many parameters as they can affect both the efficiency and the working life of the detector. The temperature of the gas inside the individual chambers is a critical parameter to be monitored, as it can both affect the efficiency of the detector and point out on-board electronic circuitry overheating. In this paper we propose a novel gas temperature sensing system based on optical fibre technology. The adopted technology is well suited to make distributed sensing systems with large number of sensors, it is immune to electromagnetic disturbances and it has adequate radiation hardness. A prototype of the basic sensor of the proposed system was tested at the experimental facility for Resistive Plate Chamber characterization available at the INFN laboratories in Frascati. Results are presented and discussed.

  20. Portable spectrometer monitors inert gas shield in welding process

    NASA Technical Reports Server (NTRS)

    Grove, E. L.

    1967-01-01

    Portable spectrometer using photosensitive readouts, monitors the amount of oxygen and hydrogen in the inert gas shield of a tungsten-inert gas welding process. A fiber optic bundle transmits the light from the welding arc to the spectrometer.

  1. Design of Plant Gas Exchange Experiments in a Variable Pressure Growth Chamber

    NASA Technical Reports Server (NTRS)

    Corey, Kenneth A.

    1996-01-01

    Sustainable human presence in extreme environments such as lunar and martian bases will require bioregenerative components to human life support systems where plants are used for generation of oxygen, food, and water. Reduced atmospheric pressures will be used to minimize mass and engineering requirements. Few studies have assessed the metabolic and developmental responses of plants to reduced pressure and varied oxygen atmospheres. The first tests of hypobaric pressures on plant gas exchange and biomass production at the Johnson Space Center will be initiated in January 1996 in the Variable Pressure Growth Chamber (VPGC), a large, closed plant growth chamber rated for 10.2 psi. Experiments were designed and protocols detailed for two complete growouts each of lettuce and wheat to generate a general database for human life support requirements and to answer questions about plant growth processes in reduced pressure and varied oxygen environments. The central objective of crop growth studies in the VPGC is to determine the influence of reduced pressure and reduced oxygen on the rates of photosynthesis, dark respiration, evapotranspiration and biomass production of lettuce and wheat. Due to the constraint of one experimental unit, internal controls, called pressure transients, will be used to evaluate rates of CO2 uptake, O2 evolution, and H2O generation. Pressure transients will give interpretive power to the results of repeated growouts at both reduced and ambient pressures. Other experiments involve the generation of response functions to partial pressures of O2 and CO2 and to light intensity. Protocol for determining and calculating rates of gas exchange have been detailed. In order to build these databases and implement the necessary treatment combinations in short time periods, specific requirements for gas injections and removals have been defined. A set of system capability checks will include determination of leakage rates conducted prior to the actual crop

  2. Exposure chamber

    DOEpatents

    Moss, Owen R.

    1980-01-01

    A chamber for exposing animals, plants, or materials to air containing gases or aerosols is so constructed that catch pans for animal excrement, for example, serve to aid the uniform distribution of air throughout the chamber instead of constituting obstacles as has been the case in prior animal exposure chambers. The chamber comprises the usual imperforate top, bottom and side walls. Within the chamber, cages and their associated pans are arranged in two columns. The pans are spaced horizontally from the walls of the chamber in all directions. Corresponding pans of the two columns are also spaced horizontally from each other. Preferably the pans of one column are also spaced vertically from corresponding pans of the other column. Air is introduced into the top of the chamber and withdrawn from the bottom. The general flow of air is therefore vertical. The effect of the horizontal pans is based on the fact that a gas flowing past the edge of a flat plate that is perpendicular to the flow forms a wave on the upstream side of the plate. Air flows downwardly between the chamber walls and the outer edges of the pan. It also flows downwardly between the inner edges of the pans of the two columns. It has been found that when the air carries aerosol particles, these particles are substantially uniformly distributed throughout the chamber.

  3. Combustion of liquid fuel in the counter-swirled jets of a gas turbine plant annular combustion chamber

    NASA Astrophysics Data System (ADS)

    Tumanovskii, A. G.; Semichastnyi, N. N.; Sokolov, K. Iu.

    1986-03-01

    Tests were carried out on an annular combustion chamber rig with a stabilizer of the type used in the GTN-25 gas turbine plant to determine the feasibility of burning a liquid fuel (diesel fuel, GOST 4749-73) in a combustion chamber of this type. Very high performance was obtained for a number of important characteristics of the microflame combustion process in counterswirled jets where all the air was supplied through the front unit of the chamber. However, the tests did not make it possible to solve some of the problems which arise when operating under full-scale conditions, such as the required high combustion efficiency under variable operating conditions of a gas turbine plant; elimination of soot formation at the walls of the stabilizer and the internal surfaces of the pipes supplying fuel to the atomizers; and a decrease in smoking under conditions of excess air factor.

  4. Simplified Method for Quantifying Theoretical Underestimation of Chamber-Based Trace Gas Fluxes

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The vast majority of studies examining soil-atmosphere exchange of nitrous oxide (N2O) have utilized chambers placed on the soil surface. Chambers are also used to measure soil respiration and carbon dioxide (CO2) exchange. It is widely recognized that chambers generate substantial errors in flux es...

  5. Noble gas atmospheric monitoring at reprocessing facilities

    SciTech Connect

    Nakhleh, C.W.; Perry, R.T. Jr.; Poths, J.; Stanbro, W.D.; Wilson, W.B.; Fearey, B.L.

    1997-05-01

    The discovery in Iraq after the Gulf War of the existence of a large clandestine nuclear-weapon program has led to an across-the-board international effort, dubbed Programme 93+2, to improve the effectiveness and efficiency of International Atomic Energy Agency (IAEA) safeguards. One particularly significant potential change is the introduction of environmental monitoring (EM) techniques as an adjunct to traditional safeguards methods. Monitoring of stable noble gas (Kr, Xe) isotopic abundances at reprocessing plant stacks appears to be able to yield information on the burnup and type of the fuel being processed. To estimate the size of these signals, model calculations of the production of stable Kr, Xe nuclides in reactor fuel and the subsequent dilution of these nuclides in the plant stack are carried out for two case studies: reprocessing of PWR fuel with a burnup of 35 GWd/tU, and reprocessing of CAND fuel with a burnup of 1 GWd/tU. For each case, a maximum-likelihood analysis is used to determine the fuel burnup and type from the isotopic data.

  6. Air Monitoring for Hazardous Gas Detection

    NASA Technical Reports Server (NTRS)

    Arkin, C. Richard; Naylor, Guy; Haskell, William; Floyd, David; Curley, Charles; Griffin, Timothy P.; Adams, Frederick; Follistein, Duke

    2003-01-01

    The Hazardous Gas Detection Lab is involved in the design and development of instrumentation that can detect and quantify various hazardous gases. Traditionally these systems are designed for leak detection of the cryogenic gases used for the propulsion of the Shuttle and other vehicles. Mass spectrometers are the basis of these systems, which provide excellent quantitation, sensitivity, selectivity, response and limits of detection. Unfortunately, these systems are large, heavy and expensive. This feature limits the ability to perform gas analysis in certain applications. Smaller and lighter mass spectrometer systems could be used in many more applications primarily due to the portability of the system. Such applications would include air analysis in confined spaces, in-situ environmental analysis and emergency response. In general, system cost is lowered as size is reduced. With a low cost air analysis system, several systems could be utilized for monitoring large areas. These networked systems could be deployed at job-sites for worker safety, throughout a community for pollution warnings, or dispersed in a battlefield for early warning of chemical or biological threats. Presented will be information on the first prototype of this type of system. Included will be field trial data, with this prototype performing air analysis autonomously from an aircraft.

  7. Development and application of noninvasive technology for study of combustion in a combustion chamber of gas turbine engine

    NASA Astrophysics Data System (ADS)

    Inozemtsev, A. A.; Sazhenkov, A. N.; Tsatiashvili, V. V.; Abramchuk, T. V.; Shipigusev, V. A.; Andreeva, T. P.; Gumerov, A. R.; Ilyin, A. N.; Gubaidullin, I. T.

    2015-05-01

    The paper formulates the issue of development of experimental base with noninvasive optical-electronic tools for control of combustion in a combustion chamber of gas turbine engine. The design and specifications of a pilot sample of optronic system are explained; this noninvasive system was created in the framework of project of development of main critical technologies for designing of aviation gas turbine engine PD-14. The testbench run data are presented.

  8. Measurements of Gas-Wall Partitioning of Oxidized Species in Environmental Smog Chambers and Teflon Sampling Lines

    NASA Astrophysics Data System (ADS)

    Krechmer, J.; Pagonis, D.; Ziemann, P. J.; Jimenez, J. L.

    2015-12-01

    Environmental "smog" chambers have played an integral role in atmospheric aerosol research for decades. Recently, many works have demonstrated that the loss of gas-phase material to fluorinated ethylene propylene (FEP) chamber walls can have significant effects on secondary organic aerosol (SOA) yield results. The effects of gas-wall partitioning on highly oxidized species is still controversial, however. In this work we performed a series of experiments examining the losses of oxidized gas-phase compounds that were generated in-situ­ in an environmental chamber. The loss of species to the walls was measured using three chemical ionization mass spectrometry techniques: proton-transfer-reaction (PTR), nitrate (NO3-) ion, and iodide (I-). Many oxidized species have wall loss timescales ranging between 15 to 45 minutes and scale according to the molecule's estimated saturation concentration c* and functional groups. By comparing results of the different techniques, and in particular by the use of the "wall-less" NO3- source, we find that measuring species with high chamber wall-loss rates is complicated by the use of a standard ion-molecule reaction (IMR) region, as well as long Teflon sampling lines, which can be important sinks for gas-phase species. This effect is observed even for semi-volatile species and could have significant effects on ambient sampling techniques that make highly time-resolved measurements using long sampling lines, such as eddy covariance measurements.

  9. Test beam results of a low-pressure micro-strip gas chamber with a secondary-electron emitter

    SciTech Connect

    Kwan, S.; Anderson, D.F.; Zimmerman, J.; Sbarra, C.; Salomon, M.

    1994-10-01

    We present recent results, from a beam test, on the angular dependence of the efficiency and the distribution of the signals on the anode strips of a low-pressure microstrip gas chamber with a thick CsI layer as a secondary-electron emitter. New results of CVD diamond films as secondary-electron emitters are discussed.

  10. Sensitivity of laser flare photometry compared to slit-lamp cell evaluation in monitoring anterior chamber inflammation in uveitis.

    PubMed

    Bernasconi, Ottavio; Papadia, Marina; Herbort, Carl P

    2010-10-01

    To study the sensitivity of laser flare photometry (LFP) in monitoring anterior chamber inflammation by correlating LFP measurements with slit-lamp evaluation of aqueous cells in HLA-B27-related uveitis in a prospective trial. Slit-lamp cell evaluation was correlated with LFP-measured flare in a masked fashion in HLA-B27-related uveitis patients receiving standard topical therapy. At the time of 50 and 90% LFP flare reduction, the corresponding reduction of cells was recorded and statistically compared using the sign test. Forty-three episodes (in 43 patients) of acute anterior HLA-B27-related uveitis were included. LFP flare reduction and slit-lamp cell reduction were strongly correlated. LFP was significantly more sensitive for both 50% (P = 0.001) and 90% (P = 0.02) LFP flare reduction in assessing the decrease of anterior chamber inflammation. LFP was superior to slit-lamp cell evaluation in monitoring anterior chamber inflammation in uveitis. Flare, becoming a quantitative parameter when measured by LFP, rather than cells, should be considered the gold standard to measure anterior chamber inflammation in uveitis. PMID:20686916

  11. Off-site air monitoring following methyl bromide chamber and building fumigations and evaluation of the ISCST air dispersion model

    SciTech Connect

    Barry, T.; Swgawa, R.; Wofford, P.

    1995-12-31

    The Department of Pesticide Regulation`s preliminary risk characterization of methyl bromide indicated an inadequate margin of safety for several exposure scenarios. Characterization of the air concentrations associated with common methyl bromide use patterns was necessary to determine specific scenarios that result in an unacceptable margin of safety. Field monitoring data were used in conjunction with the Industrial Source Complex, Short Tenn (ISCST) air dispersion model to characterize air concentrations associated with various types of methyl bromide applications. Chamber and building fumigations were monitored and modelled. For each fumigation the emission rates, chamber or building specifications and on-site meteorological data were input into the ISCST model. The model predicted concentrations were compared to measured air concentrations. The concentrations predicted by the ISCST model reflect both the pattern and magnitude of the measured concentrations. Required buffer zones were calculated using the ISCST output.

  12. Compact integrated X-ray intensity and beam position monitor based on rare gas scintillation

    SciTech Connect

    Revesz, Peter; Ruff, Jacob; Dale, Darren; Krawczyk, Thomas

    2013-05-15

    We have created and tested a compact integrated X-ray beam intensity and position monitor using Ar-gas scintillation. The light generated inside the device's cavity is detected by diametrically opposed PIN diodes located above and below the beam. The intensity is derived from the sum of the top and bottom signals, while the beam position is calculated from the difference-over-sum of the two signals. The device was tested at Cornell High Energy Synchrotron Source with both 17 keV and 59 keV x-rays. For intensity monitoring, the Ar-scintillation monitor performance is comparable to standard ion chambers in terms of precision. As an X-ray beam position monitor the new device response is linear with vertical beam position over a 2 mm span with a precision of 2 {mu}m.

  13. Characterization and performances of a monitoring ionization chamber dedicated to IBA-universal irradiation head for Pencil Beam Scanning

    NASA Astrophysics Data System (ADS)

    Courtois, C.; Boissonnat, G.; Brusasco, C.; Colin, J.; Cussol, D.; Fontbonne, J. M.; Marchand, B.; Mertens, T.; de Neuter, S.; Peronnel, J.

    2014-02-01

    Every radiotherapy center has to be equipped with real-time beam monitoring devices. In 2008, we developed an ionization chamber in collaboration with the IBA (Ion Beam Applications) company. This monitoring device called IC2/3 was developed to be used in IBA universal irradiation head for Pencil Beam Scanning (PBS). Here we present the characterization of the IC2/3 monitor in the energy and flux ranges used in protontherapy. The equipment has been tested with an IBA cyclotron able to deliver proton beams from 70 to 230 MeV. This beam monitoring device has been validated and is now installed at the Westdeutsches Protonentherapiezentrum Essen protontherapy center (WPE, Germany). The results obtained in both terms of spatial resolution and dose measurements are at least equal to the initial specifications needed for PBS purposes. The detector measures the dose with a relative uncertainty lower than 1% in the range from 0.5 Gy/min to 8 Gy/min while the spatial resolution is better than 250 μm. The technology has been patented and five IC2/3 chambers were delivered to IBA. Nowadays, IBA produces the IC2/3 beam monitoring device as a part of its Proteus 235 product.

  14. Detection efficiency of a high-pressure gas scintillation proportional chamber.

    PubMed

    Fahey, F H; Zimmerman, R E; Judy, P F; Lanza, R C

    1987-01-01

    The detection efficiency of a high-pressure, gas scintillation proportional chamber (GSPC), designed for medical imaging in the 30-150 keV energy range, has been investigated through measurement and Monte Carlo simulation. Measurements were conducted on a GSPC containing 4 atm of pure xenon separated from a hexagonal array of seven ultraviolet-sensitive photomultiplier tubes by 1.27-cm-thick fused-silica windows. Experimental measurements of the photopeak efficiency, fluorescence escape efficiency, and the energy collection efficiency were obtained. Results were also obtained for different photon energies and different values of temporal resolution. The measurements were compared with the results obtained from a Monte Carlo simulation designed specifically for investigating the imaging of low-energy photons (below 150 keV) with a gas-filled detector. The simulation was used to estimate photopeak efficiency, fluorescence escape efficiency, photopeak-to-fluorescence escape peak ratio, quantum interaction efficiency, energy collection efficiency, and local energy collection efficiency. The photopeak efficiency of the GSPC relative to that of a 3-in. (7.62-cm)-thick sodium iodide crystal was measured to be 0.284 +/- 0.001 at 60 keV and 0.057 +/- 0.001 at 140 keV. Of the 60-keV photons incident upon the detector, 70% +/- 4% interacted in the detector, with 28% +/- 1% being in the photopeak, as estimated both by experimentation and through the simulation. The maximum energy collection efficiency was found to be 65% at 60 keV, with 46% being deposited within 0.2 cm of the initial photon interaction. The information gained from this study is being used to design an optimized detector for use in specialized nuclear medicine studies. PMID:3561331

  15. Internal flow-field measurements in a model can-type gas-turbine combustion chamber

    NASA Astrophysics Data System (ADS)

    Koutmos, P.; McQuirk, J. J.; Vafidis, C.

    LDA measurements of the three mean velocity components and the corresponding turbulence intensities have been made to provide qualitative and quantitative information on the flow-field in a water model of a can-type gas turbine combustion chamber. The combustor geometry comprised a swirl driven primary zone, annulus fed rows of primary and secondary jets and an exit contraction nozzle. Flow visualization revealed a stable and symmetric vortex established within the primary zone via the combined effects of the inlet swirl and primary jet impingement. High levels of turbulence kinetic energy were generated within the vortex as well as near the location where the jets impinged. Large streamline curvature, anisotropy of the turbulence structure and very rapid transfer of momentum from the radial to the axial direction were associated with this primary region. In the downstream dilution zone a shallower jet trajectory was observed and the larger turbulence kinetic energy levels could be identified in this region with the shear layers formed between the bulk flow emerging from the primary zone and the incoming secondary jets. Moderate levels of spatial non-uniformities were measured at the exit from the nozzle.

  16. Development of Electron Tracking Compton Camera using micro pixel gas chamber for medical imaging

    NASA Astrophysics Data System (ADS)

    Kabuki, Shigeto; Hattori, Kaori; Kohara, Ryota; Kunieda, Etsuo; Kubo, Atsushi; Kubo, Hidetoshi; Miuchi, Kentaro; Nakahara, Tadaki; Nagayoshi, Tsutomu; Nishimura, Hironobu; Okada, Yoko; Orito, Reiko; Sekiya, Hiroyuki; Shirahata, Takashi; Takada, Atsushi; Tanimori, Toru; Ueno, Kazuki

    2007-10-01

    We have developed the Electron Tracking Compton Camera (ETCC) with reconstructing the 3-D tracks of the scattered electron in Compton process for both sub-MeV and MeV gamma rays. By measuring both the directions and energies of not only the recoil gamma ray but also the scattered electron, the direction of the incident gamma ray is determined for each individual photon. Furthermore, a residual measured angle between the recoil electron and scattered gamma ray is quite powerful for the kinematical background rejection. For the 3-D tracking of the electrons, the Micro Time Projection Chamber (μ-TPC) was developed using a new type of the micro pattern gas detector. The ETCC consists of this μ-TPC (10×10×8 cm 3) and the 6×6×13 mm 3 GSO crystal pixel arrays with a flat panel photo-multiplier surrounding the μ-TPC for detecting recoil gamma rays. The ETCC provided the angular resolution of 6.6° (FWHM) at 364 keV of 131I. A mobile ETCC for medical imaging, which is fabricated in a 1 m cubic box, has been operated since October 2005. Here, we present the imaging results for the line sources and the phantom of human thyroid gland using 364 keV gamma rays of 131I.

  17. Heavy ion beam propagation through a gas-filled chamber for inertial confinement fusion

    SciTech Connect

    Barboza, N.O.

    1996-10-01

    The work presented here evaluates the dynamics of a beam of heavy ions propagating through a chamber filled with gas. The motivation for this research stems from the possibility of using heavy ion beams as a driver in inertial confinement fusion reactors for the purpose of generating electricity. Such a study is important in determining the constraints on the beam which limit its focus to the small radius necessary for the ignition of thermonuclear microexplosions which are the source of fusion energy. Nuclear fusion is the process of combining light nuclei to form heavier ones. One possible fusion reaction combines two isotopes of hydrogen, deuterium and tritium, to form an alpha particle and a neutron, with an accompanying release of {approximately}17.6 MeV of energy. Generating electricity from fusion requires that we create such reactions in an efficient and controlled fashion, and harness the resulting energy. In the inertial confinement fusion (ICF) approach to energy production, a small spherical target, a few millimeters in radius, of deuterium and tritium fuel is compressed so that the density and temperature of the fuel are high enough, {approximately}200 g/cm{sup 3} and {approximately}20 keV, that a substantial number of fusion reactions occur; the pellet microexplosion typically releases {approximately}350 MJ of energy in optimized power plant scenarios.

  18. Design and characterization of a smog chamber for studying gas-phase chemical mechanisms and aerosol formation

    NASA Astrophysics Data System (ADS)

    Wang, X.; Liu, T.; Bernard, F.; Ding, X.; Wen, S.; Zhang, Y.; Zhang, Z.; He, Q.; Lü, S.; Chen, J.; Saunders, S.; Yu, J.

    2014-01-01

    We describe here characterization of a new state-of-the-art smog chamber facility for studying atmospheric gas-phase and aerosol chemistry. The chamber consists of a 30 m3 fluorinated ethylene propylene (FEP) Teflon film reactor housed in a temperature-controlled enclosure equipped with black lamps as the light source. Temperature can be set in the range from -10 to 40 °C at accuracy of ±1 °C as measured by eight temperature sensors inside the enclosure and one just inside the reactor. Matrix air can be purified with non-methane hydrocarbons (NMHCs) < 0.5 ppb, NOx/O3/carbonyls < 1 ppb and particles < 1 cm-3. The photolysis rate of NO2 is adjustable between 0 and 0.49 min-1. At 298 K under dry conditions, the average wall loss rates of NO, NO2 and O3 were measured to be 1.41 × 10-4 min-1, 1.39 × 10-4 min-1 and 1.31 × 10-4 min-1, respectively, and the particle number wall loss rate was measured to be 0.17 h-1. Auxiliary mechanisms of this chamber are determined and included in the Master Chemical Mechanism to evaluate and model propene-NOx-air irradiation experiments. The results indicate that this new smog chamber can provide high-quality data for mechanism evaluation. Results of α-pinene dark ozonolysis experiments revealed secondary organic aerosol (SOA) yields comparable to those from other chamber studies, and the two-product model gives a good fit for the yield data obtained in this work. Characterization experiments demonstrate that our Guangzhou Institute of Geochemistry, Chinese Academy Sciences (GIG-CAS), smog chamber facility can be used to provide valuable data for gas-phase chemistry and secondary aerosol formation.

  19. Effects of Soil Physical Non-Uniformity on Chamber-Based Gas Flux Estimates

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Chamber methods for measuring trace gases fluxes are prone to errors resulting in large part from alteration of near-surface concentration gradients. There is little information available for estimating the magnitude of such errors that simultaneously accounts for soil physical properties, chamber d...

  20. USDA-ARS GRACEnet Project Protocols, Chapter 3. Chamber-based trace gas flux measurements4

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This protocol addresses N2O, CO2 and CH4 flux measurement by soil chamber methodology. The reactivities of other gasses of interest such as NOx O3, CO, and NH3 will require different chambers and associated instrumentation. Carbon dioxide is included as an analyte with this protocol; however, when p...

  1. Acoustic tuning of gas liquid scheme injectors for acoustic damping in a combustion chamber of a liquid rocket engine

    NASA Astrophysics Data System (ADS)

    Sohn, Chae Hoon; Park, I.-Sun; Kim, Seong-Ku; Jip Kim, Hong

    2007-07-01

    In a combustion chamber of a liquid rocket engine, acoustic fine-tuning of gas-liquid scheme injectors is studied numerically for acoustic stability by adopting a linear acoustic analysis. Injector length and blockage ratio at gas inlet are adjusted for fine-tuning. First, acoustic behavior in the combustor with a single injector is investigated and acoustic-damping effect of the injector is evaluated for cold condition by the quantitative parameter of damping factor as a function of injector length. From the numerical results, it is found that the injector can play a significant role in acoustic damping when it is tuned finely. The optimum tuning-length of the injector to maximize the damping capacity corresponds to half of a full wavelength of the first longitudinal overtone mode traveling in the injector with the acoustic frequency intended for damping in the chamber. In baffled chamber, the optimum lengths of the injector are calculated as a function of baffle length for both cold and hot conditions. Next, in the combustor with numerous resonators, peculiar acoustic coupling between a combustion chamber and injectors is observed. As the injector length approaches a half-wavelength, the new injector-coupled acoustic mode shows up and thereby, the acoustic-damping effect of the tuned injectors is appreciably degraded. And, damping factor maintains a near-constant value with blockage ratio and then, decreases rapidly. Blockage ratio affects also acoustic damping and should be considered for acoustic tuning.

  2. Colorimetric blood-gas monitoring sensors

    NASA Astrophysics Data System (ADS)

    Proctor, Keith J.; Seifert, George P.

    1993-05-01

    Colorimetric fiber optic sensors have been developed for measuring the pH and pCO2 of blood. These sensors are fabricated using a single 125 micrometers diameter optical fiber. Located at the distal end of the fiber is a capsule that contains a pH sensitive dye. The pCO2 sensor is fabricated from a pH sensor with the addition of a salt, bicarbonate, and the encapsulation with an ion impermeable gas permeable membrane. The distal end of the capsule is terminated with a reflective surface. The reflective surface can either be a polished metallic surface or, in this case, a TiO2 impregnated epoxy. The disposable sensor mates with an optical connector that contains two optical fibers of the same size as the disposable sensor. The two fibers within the optical cable provide a light path for both the antegrade and retrograde optical signals. These fibers are terminated at either the LED source or the detector. A prototype sensor assembly that incorporates the measurement of three physiological parameters (pH, pCO2, and sO2) has been demonstrated to fit within a standard 20 gauge arterial catheter, typically used for radial artery blood pressure monitoring, without significant damping of the blood pressure waveform. The pH sensor has a range of 6.9 - 7.8 with a precision of 0.01 pH units and the pCO2 sensor has a range of 15 - 95 mm Hg with a precision of 3 mm Hg. The long term drift pH drift is less than 0.01 pH unit per 8 hours and the pCO2 drift is less than 1 mm Hg per 8 hours. Sensor performance in the canine has demonstrated that the pH sensor is accurate to within +/- 0.03 pH units and the pCO2 sensor is accurate to within +/- 3 mm Hg when compared to a typical blood gas analyzer.

  3. Operating Experience Review of the INL HTE Gas Monitoring System

    SciTech Connect

    L. C. Cadwallader; K. G. DeWall

    2010-06-01

    This paper describes the operations of several types of gas monitors in use at the Idaho National Laboratory (INL) High Temperature Electrolysis Experiment (HTE) laboratory. The gases monitored at hydrogen, carbon monoxide, carbon dioxide, and oxygen. The operating time, calibration, and unwanted alarms are described. The calibration session time durations are described. Some simple statistics are given for the reliability of these monitors and the results are compared to operating experiences of other types of monitors.

  4. New Hadron Monitor By Using A Gas-Filled RF Resonator

    SciTech Connect

    Yonehara, Katsuya; Fasce, Giorgio; Flanagan, Gene; Johnson, Rolland; Tollestrup, Alvin; Zwaska, Robert

    2015-05-01

    It is trend to build an intense neutrino beam facility for the fundamental physics research, e.g. LBNF at Fermilab, T2K at KEK, and CNGS at CERN. They have investigated a hadron monitor to diagnose the primary/secondary beam quality. The existing hadron monitor based on an ionization chamber is not robust in the high-radiation environment vicinity of MW-class secondary particle production targets. We propose a gas-filled RF resonator to use as the hadron monitor since it is simple and hence radiation robust in this environment. When charged particles pass through the resonator they produce ionized plasma via the Coulomb interaction with the inert gas. The beam-induced plasma changes the permittivity of inert gas. As a result, a resonant frequency in the resonator shifts with the amount of ionized electrons. The radiation sensitivity is adjustable by the inert gas pressure and the RF amplitude. The hadron profile will be reconstructed with a tomography technique in the hodoscope which consists of X, Y, and theta layers by using a strip-shaped gas resonator. The sensitivity and possible system design will be shown in this presentation.

  5. Engineering considerations for corrosion monitoring of gas gathering pipeline systems

    SciTech Connect

    Braga, T.G.; Asperger, R.G.

    1987-01-01

    Proper corrosion monitoring of gas gathering pipelines requires a system review to determine the appropriate monitor locations and types of monitoring techniques. This paper develops and discusses a classification of conditions such as flow regime and gas composition. Also discussed are junction categories which, for corrosion monitoring, need to be considered from two points of view. The first is related to fluid flow in the line and the second is related corrosion inhibitor movement along the pipeline. The appropriate application of the various monitoring techniques such as coupons, hydrogen detectors, electrical resistance probe and linear polarization probes are discussed in relation to flow regime and gas composition. Problems caused by semi-conduction from iron sulfide are considered. Advantages and disadvantages of fluid gathering methods such as pots and flow-through drips are discussed in relation to their reliability as on-line monitoring locations.

  6. Hydrogen and Oxygen Gas Monitoring System Design and Operation

    SciTech Connect

    Lee C. Cadwallader; Kevin G. DeWall; J. Stephen Herring

    2007-06-01

    This paper describes pertinent design practices of selecting types of monitors, monitor unit placement, setpoint selection, and maintenance considerations for gas monitors. While hydrogen gas monitors and enriched oxygen atmosphere monitors as they would be needed for hydrogen production experiments are the primary focus of this paper, monitors for carbon monoxide and carbon dioxide are also discussed. The experiences of designing, installing, and calibrating gas monitors for a laboratory where experiments in support of the DOE Nuclear Hydrogen Initiative (NHI) are described along with codes, standards, and regulations for these monitors. Information from the literature about best operating practices is also presented. The NHI program has two types of activities. The first, near-term activity is laboratory and pilot-plant experimentation with different processes in the kilogram per day scale to select the most promising types of processes for future applications of hydrogen production. Prudent design calls for indoor gas monitors to sense any hydrogen leaks within these laboratory rooms. The second, longer-term activity is the prototype, or large-scale plants to produce tons of hydrogen per day. These large, outdoor production plants will require area (or “fencepost”) monitoring of hydrogen gas leaks. Some processes will have oxygen production with hydrogen production, and any oxygen releases are also safety concerns since oxygen gas is the strongest oxidizer. Monitoring of these gases is important for personnel safety of both indoor and outdoor experiments. There is some guidance available about proper placement of monitors. The fixed point, stationary monitor can only function if the intruding gas contacts the monitor. Therefore, monitor placement is vital to proper monitoring of the room or area. Factors in sensor location selection include: indoor or outdoor site, the location and nature of potential vapor/gas sources, chemical and physical data of the

  7. [Monitoring gas concentration from carbon emissions by remote sensing].

    PubMed

    Wang, Li-Wen; Wei, Ya-Xing

    2012-06-01

    Global climate warming has become the focus question of international global climate change research, and is an important factor influencing world economy, political situation, and ecological environment. Produced carbon emission gases such as CO2, CH4, N2O, etc. caused by human activity are the main reason for global warming. In order to forecast future climate change and construct accurate carbon cycle model, monitoring accuracy of gas concentration from carbon emission must be improved. In the present paper, the newest progress in the international research results about monitoring gas concentration from carbon emissions by remote sensing was considered, monitoring method for carbon emissions was introduced, and remotely sensed monitoring technology about gas concentration from carbon emissions (including thermal infrared, sun spectrum, active remote sensing monitoring technology) was stated. In detail, several present and future satellite sensors were introduced (including TOVS, AIRS, IASI, SCIAMACHY, GOSAT, OCO, A-SCOPE and ASCENDS), and monitoring results achieved by these sensors were analyzed. PMID:22870656

  8. Ionization chamber

    DOEpatents

    Walenta, Albert H.

    1981-01-01

    An ionization chamber has separate drift and detection regions electrically isolated from each other by a fine wire grid. A relatively weak electric field can be maintained in the drift region when the grid and another electrode in the chamber are connected to a high voltage source. A much stronger electric field can be provided in the detection region by connecting wire electrodes therein to another high voltage source. The detection region can thus be operated in a proportional mode when a suitable gas is contained in the chamber. High resolution output pulse waveforms are provided across a resistor connected to the detection region anode, after ionizing radiation enters the drift region and ionize the gas.

  9. Ionization chamber

    DOEpatents

    Walenta, A.H.

    An ionization chamber is described which has separate drift and detection regions electrically isolated from each other by a fine wire grid. A relatively weak electric field can be maintained in the drift region when the grid and another electrode in the chamber are connected to a high voltage source. A much stronger electric field can be provided in the detection region by connecting wire electrodes therein to another high voltage source. The detection region can thus be operated in a proportional mode when a suitable gas is contained in the chamber. High resolution output pulse waveforms are provided across a resistor connected to the detection region anode, after ionizing radiation enters the drift region and ionizes the gas.

  10. Modeling SOA formation from alkanes and alkenes in chamber experiments: effect of gas/wall partitioning of organic vapors.

    NASA Astrophysics Data System (ADS)

    Stéphanie La, Yuyi; Camredon, Marie; Ziemann, Paul; Ouzebidour, Farida; Valorso, Richard; Madronich, Sasha; Lee-Taylor, Julia; Hodzic, Alma; Aumont, Bernard

    2014-05-01

    Oxidation products of Intermediate Volatility Organic Compounds (IVOC) are expected to be the major precursors of secondary organic aerosols (SOA). Laboratory experiments were conducted this last decade in the Riverside APRC chamber to study IVOC oxidative mechanisms and SOA formation processes for a large set of linear, branched and cyclic aliphatic hydrocarbons (Ziemann, 2011). This dataset are used here to assess the explicit oxidation model GECKO-A (Generator for Explicit Chemistry and Kinetics of Organics in the Atmosphere) (Aumont et al., 2005). The simulated SOA yields agree with the general trends observed in the chamber experiments. They are (i) increasing with the increasing carbon number; (ii) decreasing with increasing methyl branch number; and (iii) increasing for cyclic compounds compared to their corresponding linear analogues. However, simulated SOA yields are systematically overestimated regardless of the precursors, suggesting missing processes in the model. In this study, we assess whether gas-to-wall partitioning of organic vapors can explain these model/observation mismatches (Matsunaga and Ziemann, 2010). First results show that GECKO-A outputs better match the observations when wall uptake of organic vapors is taken into account. Effects of gas/wall partitioning on SOA yields and composition will be presented. Preliminary results suggest that wall uptake is a major process influencing SOA production in the Teflon chambers. References Aumont, B., Szopa, S., Madronich, S.: Modelling the evolution of organic carbon during its gas-phase tropospheric oxidation: development of an explicit model based on a self generating approach. Atmos.Chem.Phys., 5, 2497-2517 (2005). P. J. Ziemann: Effects of molecular structure on the chemistry of aerosol formation from the OH-radical-initiated oxidation of alkanes and alkenes, Int. Rev.Phys.Chem., 30:2, 161-195 (2011). Matsunaga, A., Ziemann, P. J.: Gas-wall partitioning of organic compounds in a Teflon film

  11. The carrier gas pressure effect in a laminar flow diffusion chamber, homogeneous nucleation of n-butanol in helium.

    PubMed

    Hyvärinen, Antti-Pekka; Brus, David; Zdímal, Vladimír; Smolík, Jiri; Kulmala, Markku; Viisanen, Yrjö; Lihavainen, Heikki

    2006-06-14

    Homogeneous nucleation rate isotherms of n-butanol+helium were measured in a laminar flow diffusion chamber at total pressures ranging from 50 to 210 kPa to investigate the effect of carrier gas pressure on nucleation. Nucleation temperatures ranged from 265 to 280 K and the measured nucleation rates were between 10(2) and 10(6) cm(-3) s(-1). The measured nucleation rates decreased as a function of increasing pressure. The pressure effect was strongest at pressures below 100 kPa. This negative carrier gas effect was also temperature dependent. At nucleation temperature of 280 K and at the same saturation ratio, the maximum deviation between nucleation rates measured at 50 and 210 kPa was about three orders of magnitude. At nucleation temperature of 265 K, the effect was negligible. Qualitatively the results resemble those measured in a thermal diffusion cloud chamber. Also the slopes of the isothermal nucleation rates as a function of saturation ratio were different as a function of total pressure, 50 kPa isotherms yielded the steepest slopes, and 210 kPa isotherms the shallowest slopes. Several sources of inaccuracies were considered in the interpretation of the results: uncertainties in the transport properties, nonideal behavior of the vapor-carrier gas mixture, and shortcomings of the used mathematical model. Operation characteristics of the laminar flow diffusion chamber at both under-and over-pressure were determined to verify a correct and stable operation of the device. We conclude that a negative carrier gas pressure effect is seen in the laminar flow diffusion chamber and it cannot be totally explained with the aforementioned reasons. PMID:16784271

  12. Burning carbon monoxide in the settling chamber of a hotshot wind tunnel for obtaining the CO2 test gas

    NASA Astrophysics Data System (ADS)

    Shumskii, V. V.; Yaroslavtsev, M. I.

    2016-03-01

    A method of formation and heating of CO2 as a test gas in the settling chamber of a hotshot wind tunnel is considered. To form and heat CO2, the chamber is filled with a source gas mixture of CO, O2, and CO2, and after initiation, these substances participate in an exothermic chemical reaction in accordance with the formula CO + 0.5 O2 + xCO2 = (1 + x)CO2. A stoichiometric ratio of the concentrations of carbon monoxide CO and oxygen is used. Variation of the number of moles x of ballast CO2 in the left part of the chemical formula allows changing the temperature of the resultant test gas in a wide range. Experiments in the IT-302M hotshot wind tunnel carried out at ITAM SB RAS have shown that a pressure increase during an isochoric process in the settling chamber due to the joint effect of heat released in the reaction CO + 0.5 O2 and an electric charge provides the completeness of CO combustion almost equal to unity. The time of reaction completion at its initiation by an electric arc is no more than several milliseconds.

  13. Chamber leakage effects on measured gas concentrations during contained demilitarization tests at NTS X-Tunnel

    SciTech Connect

    Christopher R. Shadix; Joel Lipkin

    1999-11-01

    A series of contained explosive detonation and propellant burn experiments was conducted during 1996 and 1997 using a specially constructed, large, underground chamber located in the X-tunnel complex at Area 25 of the Nevada Test Site (NTS).

  14. Deposition and characterization of alumina-titania coating by multi-chamber gas-dynamic sprayer

    NASA Astrophysics Data System (ADS)

    Kovaleva, M.; Prozorova, M.; Arseenko, M.; Tyurin, Yu.; Kolisnichenko, O.; Vasilik, N.; Sirota, V.; Pavlenko, I.

    In this paper, alumina-titania coatings have been formed on aluminium substrate by multi-chamber detonation sprayer. The coatings were investigated using SEM, EDS, XRD and Vickers microhardness tester. The results show that the alumina-titania coatings consist of both fully melted regions and partially melted regions, and the fully melted region has a lamellar-like structure. The multi-chamber detonation sprayer produced the dense layers of coating with a high hardness.

  15. CONTROL OF OZONE DISINFECTION BY EXHAUST GAS MONITORING

    EPA Science Inventory

    In this paper it was demonstrated empirically that disinfection with ozone can be controlled by monitoring the exhaust gas ozone concentration exiting the contactor. This method is more reliable than measuring dissolved ozone because of the inherent difficulties and inadequacies ...

  16. Stand-alone sensors monitor for combustible gas leaks

    SciTech Connect

    Not Available

    1991-01-01

    Elizabeth Gas Co., a gas distribution company in New Jersey, has added a network of combustible gas sensors to a computer system already in place for continuous monitoring of gas leaks. The computer center at the company's Erie St. facility controls all dispatching, which includes routing gas through the system and controlling gas pressure. The system uses redundant Hewlett-Packard A900 central processing units (CPU), 6 monitors, including a Mitsubishi 35-in. color monitor, and Fisher control software. The company's primary tank farm, which contains over a million gallons of propane and LNG, is located near several chemical plants, an oil refinery and a residential neighborhood. To monitor for combustible leaks at the site, the company installed 49 stand-alone combustible gas sensors manufactured by Mine Safety Appliances Co. (MSA) of Pittsburgh, Pa. The sensors are designed to measure the concentrations of propane and LNG and trigger alarms at 20% of the lower explosive limit (LEL). The sensors are diffusion types that sample ambient air rather than drawing in samples through a pump. Using the principle of catalytic oxidation, the sensors produce a signal proportional to the concentration of combustible gas in the atmosphere. If gas is detected above 20% of the LEL, a relay driver signal is sent into a remote annunciator panel which contains LED alarm displays for each sensor. The remote annunciator panel also houses a 24 VDC power supply.

  17. Study of radiation heat transfer and the temperature state in the combustion chambers of small-size gas-turbine engines (GTEs)

    NASA Astrophysics Data System (ADS)

    Lukash, V. P.

    1993-03-01

    The experimental data on the radiation flux surface density distribution in the combusion chamber of a small-size gas-turbine engine are presented. Experiments are made at elevated pressures and temperatures of the stagnated flow at the chamber inlet. Satisfactory agreement between theory and experiment is obtained.

  18. Indirect Gas Species Monitoring Using Tunable Diode Lasers

    DOEpatents

    Von Drasek, William A.; Saucedo, Victor M.

    2005-02-22

    A method for indirect gas species monitoring based on measurements of selected gas species is disclosed. In situ absorption measurements of combustion species are used for process control and optimization. The gas species accessible by near or mid-IR techniques are limited to species that absorb in this spectral region. The absorption strength is selected to be strong enough for the required sensitivity and is selected to be isolated from neighboring absorption transitions. By coupling the gas measurement with a software sensor gas, species not accessible from the near or mid-IR absorption measurement can be predicted.

  19. Project W-030 flammable gas verification monitoring test

    SciTech Connect

    BARKER, S.A.

    1999-02-24

    This document describes the verification monitoring campaign used to document the ability of the new ventilation system to mitigate flammable gas accumulation under steady state tank conditions. This document reports the results of the monitoring campaign. The ventilation system configuration, process data, and data analysis are presented.

  20. Summary of gas release events detected by hydrogen monitoring

    SciTech Connect

    MCCAIN, D.J.

    1999-05-18

    This paper summarizes the results of monitoring tank headspace for flammable gas release events. In over 40 tank years of monitoring the largest detected release in a single-shell tank is 2.4 cubic meters of Hydrogen. In the double-shell tanks the largest release is 19.3 cubic meters except in SY-101 pre mixer pump installation condition.

  1. Raman gas analyzer applicability to monitoring of gaseous air pollution

    NASA Astrophysics Data System (ADS)

    Petrov, D. V.; Matrosov, I. I.; Tikhomirov, A. A.

    2015-11-01

    It is shown that the main problem, arising when designing a stationary Raman gas analyzer intended to monitor gaseous air pollutions, is to get SRS signals of sufficient intensity. The engineering solutions are presented that provide the required sensitivity (~ 50-100 ppb). It is achieved by compressing a gas medium under analysis and gaining intensity of the exciting laser radiation.

  2. Results of gas monitoring of double-shell flammable gas watch list tanks

    SciTech Connect

    Wilkins, N.E.

    1995-01-19

    Tanks 103-SY; 101-AW; 103-, 104-, and 105-AN are on the Flammable Gas Watch List. Recently, standard hydrogen monitoring system (SHMS) cabinets have been installed in the vent header of each of these tanks. Grab samples have been taken once per week, and a gas chromatograph was installed on tank 104-AN as a field test. The data that have been collected since gas monitoring began on these tanks are summarized in this document.

  3. Evaluation of radioisotope tracer and activation analysis techniques for contamination monitoring in space environment simulation chambers

    NASA Technical Reports Server (NTRS)

    Smathers, J. B.; Kuykendall, W. E., Jr.; Wright, R. E., Jr.; Marshall, J. R.

    1973-01-01

    Radioisotope measurement techniques and neutron activation analysis are evaluated for use in identifying and locating contamination sources in space environment simulation chambers. The alpha range method allows the determination of total contaminant concentration in vapor state and condensate state. A Cf-252 neutron activation analysis system for detecting oils and greases tagged with stable elements is described. While neutron activation analysis of tagged contaminants offers specificity, an on-site system is extremely costly to implement and provides only marginal detection sensitivity under even the most favorable conditions.

  4. A near-infrared acetylene detection system based on a 1.534 μm tunable diode laser and a miniature gas chamber

    NASA Astrophysics Data System (ADS)

    He, Qixin; Zheng, Chuantao; Liu, Huifang; Li, Bin; Wang, Yiding; Tittel, Frank K.

    2016-03-01

    A near-infrared (NIR) dual-channel differential acetylene (C2H2) detection system was experimentally demonstrated based on tunable diode laser absorption spectroscopy (TDLAS) technique and wavelength modulation spectroscopy (WMS) technique. A distributed feedback (DFB) laser modulated by a self-developed driver around 1.534 μm is used as light source. A miniature gas chamber with 15 cm path length is adopted as absorption pool, and an orthogonal lock-in amplifier is developed to extract the second harmonic (2f) signal. Sufficient standard C2H2 samples with different concentrations were prepared, and detailed measurements were carried out to study the detection performance. A good linear relationship is observed between the amplitude of the 2f signal and C2H2 concentration within the range of 200-10,000 ppm, and the relative measurement error is less than 5% within the whole range. A long-term monitoring lasting for 20 h on a 1000 ppm C2H2 sample was carried out, and the maximum concentration fluctuation is less than 2%. Due to the capability of using long-distance and low-loss optical fiber, the gas-cell can be placed in the filed for remote monitoring, which enables the system to have good prospects in industrial field.

  5. Study of d E/ d x in a Drift Chamber with He-C 2H 6 Gas Mixture

    NASA Astrophysics Data System (ADS)

    Emi, Keiko; Tsukamoto, Toshifumi; Hirano, Hiroyuki; Mamada, Haruhiko; Sakai, Yoshihide; Uno, Shoji; Itami, Shunsuke; Kajikawa, Ryoichi; Nitoh, Osamu; Ohishi, Noritsugu; Sugiyama, Akira; Suzuki, Shiro; Takahashi, Kaoru; Tamagawa, Yoichi; Tomoto, Makoto; Yamaki, Tetsuji

    1996-03-01

    We studied dE/ dx in a small-celldrift chamber filled with a gas mixture of 50% He and 50% C2H6.The dE/ dx resolution, measured in terms of the 80% truncated meanof 41 layer samples, was 5.2% when the incident angle of the trackwith respect to the wire direction was 45°.The βγ dependence showed asmaller relativistic rise than in the case of P-10 gas.At an incident angle of 90°, we observed gas gain saturationdue to the space charge effect. Although thismakes the βγ dependence of dE/ dx weaker, the dE/ dx resolution was improved. As a result,a π-K separation of 2σ is achieved at all incident anglesfor 2 GeV/c tracks.

  6. Effects of soil physical nonuniformity on chamber-based gas flux estimates

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Measurement of soil-to-atmosphere exchange of biogenic trace gases using chamber-based techniques is commonly applied to a wide range of research topics in agronomy, soil science, biogeochemistry, and ecology, including studies addressing the role of terrestrial ecosystems in regulating atmospheric ...

  7. Reception and study of lunar surface material in inert gas medium. [considering laboratory vacuum receiving chamber

    NASA Technical Reports Server (NTRS)

    Surkov, Y. A.; Rudnitskiy, Y. M.; Glotov, V. A.

    1974-01-01

    The reception and study of lunar material returned by the Luna 16 space station is described. The layout of a vacuum receiving chamber for working with material in a helium atmosphere is examined along with the main operations involved in extracting the material from the ampule and drill.

  8. On-line ultrasonic gas entrainment monitor

    DOEpatents

    Day, Clifford K.; Pedersen, Herbert N.

    1978-01-01

    Apparatus employing ultrasonic energy for detecting and measuring the quantity of gas bubbles present in liquids being transported through pipes. An ultrasonic transducer is positioned along the longitudinal axis of a fluid duct, oriented to transmit acoustic energy radially of the duct around the circumference of the enclosure walls. The back-reflected energy is received centrally of the duct and interpreted as a measure of gas entrainment. One specific embodiment employs a conical reflector to direct the transmitted acoustic energy radially of the duct and redirect the reflected energy back to the transducer for reception. A modified embodiment employs a cylindrical ultrasonic transducer for this purpose.

  9. Food monitoring based on diode laser gas spectroscopy

    NASA Astrophysics Data System (ADS)

    Lewander, M.; Guan, Z. G.; Persson, L.; Olsson, A.; Svanberg, S.

    2008-11-01

    Food is frequently packed in a controlled environment of gas, in order to extend shelf life. It is of great importance to be able to monitor the status of the packed food to ensure quality. We demonstrate a technique to monitor the gas inside packages non-intrusively by using a laser spectroscopic method in scattering solid materials. The technique named GASMAS (GAs in Scattering Media Absorption Spectroscopy) is based on tunable diode laser absorption spectroscopy and relies on the fact that free gas inside solid materials absorbs much sharper spectrally than the bulk material. Results from time dependent measurements of molecular oxygen and water vapour in packages of minced meat, bake-off bread, and the headspace of a milk carton are presented. We show that the technique allows gas measurements inside the food through the package, and assessment of the integrity of the package.

  10. Component greenhouse gas fluxes and radiative balance from two deltaic marshes in Louisiana: Pairing chamber techniques and eddy covariance

    NASA Astrophysics Data System (ADS)

    Krauss, Ken W.; Holm, Guerry O.; Perez, Brian C.; McWhorter, David E.; Cormier, Nicole; Moss, Rebecca F.; Johnson, Darren J.; Neubauer, Scott C.; Raynie, Richard C.

    2016-06-01

    Coastal marshes take up atmospheric CO2 while emitting CO2, CH4, and N2O. This ability to sequester carbon (C) is much greater for wetlands on a per area basis than from most ecosystems, facilitating scientific, political, and economic interest in their value as greenhouse gas sinks. However, the greenhouse gas balance of Gulf of Mexico wetlands is particularly understudied. We describe the net ecosystem exchange (NEEc) of CO2 and CH4 using eddy covariance (EC) in comparison with fluxes of CO2, CH4, and N2O using chambers from brackish and freshwater marshes in Louisiana, USA. From EC, we found that 182 g C m-2 yr-1 was lost through NEEc from the brackish marsh. Of this, 11 g C m-2 yr-1 resulted from net CH4 emissions and the remaining 171 g C m-2 yr-1 resulted from net CO2 emissions. In contrast, -290 g C m2 yr-1 was taken up through NEEc by the freshwater marsh, with 47 g C m-2 yr-1 emitted as CH4 and -337 g C m-2 yr-1 taken up as CO2. From chambers, we discovered that neither site had large fluxes of N2O. Sustained-flux greenhouse gas accounting metrics indicated that both marshes had a positive (warming) radiative balance, with the brackish marsh having a substantially greater warming effect than the freshwater marsh. That net respiratory emissions of CO2 and CH4 as estimated through chamber techniques were 2-4 times different from emissions estimated through EC requires additional understanding of the artifacts created by different spatial and temporal sampling footprints between techniques.

  11. New mud gas monitoring system aboard D/V Chikyu

    NASA Astrophysics Data System (ADS)

    Kubo, Yusuke; Inagaki, Fumio; Eguchi, Nobuhisa; Igarashi, Chiaki

    2013-04-01

    Mud gas logging has been commonly used in oil industry and continental scientific drilling to detect mainly hydrocarbon gases from the reservoir formation. Quick analysis of the gas provides almost real-time information which is critical to evaluate the formation and, in particular, safety of drilling operation. Furthermore, mud gas monitoring complements the lack of core or fluid samples particularly in a deep hole, and strengthen interpretations of geophysical logs. In scientific ocean drilling, on the other hand, mud gas monitoring was unavailable in riserless drilling through the history of DSDP and ODP, until riser drilling was first carried out in 2009 by D/V Chikyu. In IODP Exp 319, GFZ installed the same system with that used in continental drilling aboard Chikyu. High methane concentrations are clearly correlated with increased wood content in the cuttings. The system installation was, however, temporary and gas separator was moved during the expedition for a technical reason. In 2011, new mud gas monitoring system was installed aboard Chikyu and was used for the first time in Exp 337. The gas separator was placed on a newly branched bypass mud flow line, and the gas sample was sent to analysis unit equipped with methane carbon isotope analyzer in addition to mass spectrometer and gas chromatograph. The data from the analytical instruments is converted to depth profiles by calculating the lag effects due to mud circulation. Exp 337 was carried out from July 26 to Sep 30, 2011, at offshore Shimokita peninsula, northeast Japan, targeting deep sub-seafloor biosphere in and around coal bed. Data from the hole C0020A, which was drilled to 2466 mbsf with riser drilling, provided insights into bio-geochemical process through the depth of the hole. In this presentation, we show the design of Chikyu's new mud gas monitoring system, with preliminary data from Exp 337.

  12. Operating experience review of an INL gas monitoring system

    SciTech Connect

    Cadwallader, Lee C.; DeWall, K. G.; Herring, J. S.

    2015-03-12

    This article describes the operations of several types of gas monitors in use at the Idaho National Laboratory (INL) High Temperature Electrolysis Experiment (HTE) laboratory. The gases monitored in the lab room are hydrogen, carbon monoxide, carbon dioxide, and oxygen. The operating time, calibration, and both actual and unwanted alarms are described. The calibration session time durations are described. In addition, some simple calculations are given to estimate the reliability of these monitors and the results are compared to operating experiences of other types of monitors.

  13. Response of air-filled ion chambers to high-intensity radiation pulses

    SciTech Connect

    Plum, M.; Brown, D.

    1993-01-01

    Ion chambers are one of the most popular types of detectors used for beam loss-monitor systems. To provide a foundation for the development of future loss-monitor systems, and to fully characterize the ion chambers in use at LAMPF, we have studied the response of air-filled cylindrical ion chambers to high-intensity, short-duration radiation pulses. The most intense pulses were about 180 rad in 250 ns (the equivalent steady-state dose rate was about 700 Mrad/h). We filled our chambers with nitrogen gas at 760 Torr and air at 600 Torr. The ion chambers were driven into extreme nonlinear response. We hope these data will be used to design loss-monitor systems based on air-filled ion chambers, thus eliminating the need for gas-flow systems and/or airtight ion chambers.

  14. Response of air-filled ion chambers to high-intensity radiation pulses

    SciTech Connect

    Plum, M.; Brown, D.

    1993-06-01

    Ion chambers are one of the most popular types of detectors used for beam loss-monitor systems. To provide a foundation for the development of future loss-monitor systems, and to fully characterize the ion chambers in use at LAMPF, we have studied the response of air-filled cylindrical ion chambers to high-intensity, short-duration radiation pulses. The most intense pulses were about 180 rad in 250 ns (the equivalent steady-state dose rate was about 700 Mrad/h). We filled our chambers with nitrogen gas at 760 Torr and air at 600 Torr. The ion chambers were driven into extreme nonlinear response. We hope these data will be used to design loss-monitor systems based on air-filled ion chambers, thus eliminating the need for gas-flow systems and/or airtight ion chambers.

  15. A pressurized ion chamber monitoring system for environmental radiation measurements utilizing a wide-range temperature-compensated electrometer

    SciTech Connect

    Stevenick, W. Van . Environmental Measurements Lab.)

    1994-08-01

    The performance of a complete pressurized ion chamber (PIC) radiation monitoring system is described. The design incorporates an improved temperature-compensated electrometer which is stable to [+-]3 [center dot] 10[sup [minus]16] A over the environmental range of temperature ([minus]40 to +40 C). Using a single 10[sup 11] [Omega] feed-back resistor, the electrometer accurately measures currents over a range from 3 [center dot] 10[sup [minus]15] A to 3 [center dot] 10[sup [minus]11] A. While retaining the sensitivity of the original PIC system (the instrument responds readily to small background fluctuations on the order of 0.1 [mu]R h[sup [minus]1]), the new system measures radiation levels up to the point where the collection efficiency of the ion chamber begins to drop off, typically [approximately]27 pA at 1 mR h[sup [minus]1]. A data recorder and system controller was designed using the Tattletale[trademark] Model 4A computer. Digital data is stored on removable solid-state, credit-card style memory cards.

  16. Microfluidic chambers for monitoring leukocyte trafficking and humanized nano-proresolving medicines interactions

    PubMed Central

    Jones, Caroline N.; Dalli, Jesmond; Dimisko, Laurie; Wong, Elisabeth; Serhan, Charles N.; Irimia, Daniel

    2012-01-01

    Leukocyte trafficking plays a critical role in determining the progress and resolution of inflammation. Although significant progress has been made in understanding the role of leukocyte activation in inflammation, dissecting the interactions between different leukocyte subpopulations during trafficking is hampered by the complexity of in vivo conditions and the lack of detail of current in vitro assays. To measure the effects of the interactions between neutrophils and monocytes migrating in response to various chemoattractants, at single-cell resolution, we developed a microfluidic platform that replicates critical features of focal inflammation sites. We integrated an elastase assay into the focal chemotactic chambers (FCCs) of our device that enabled us to distinguish between phlogistic and nonphlogistic cell recruitment. We found that lipoxin A4 and resolvin D1, in solution or incorporated into nano–proresolving medicines, reduced neutrophil and monocyte trafficking toward leukotriene B4. Lipoxin A4 also reduced the elastase release from homogenous and heterogenous mixtures of neutrophils and monocytes. Surprisingly, the effect of resolvin D1 on heterogenous mixtures was antisynergistic, resulting in a transient spike in elastase activity, which was quickly terminated, and the degraded elastin removed by the leukocytes inside the FCCs. Therefore, the microfluidic assay provides a robust platform for measuring the effect of leukocyte interactions during trafficking and for characterizing the effects of inflammation mediators. PMID:23185003

  17. A smog chamber comparison of a microfluidic derivatization measurement of gas-phase glyoxal and methylglyoxal with other analytical techniques

    NASA Astrophysics Data System (ADS)

    Pang, X.; Lewis, A. C.; Richard, A.; Baeza-Romero, M. T.; Adams, T. J.; Ball, S. M.; Daniels, M. J. S.; Goodall, I. C. A.; Monks, P. S.; Peppe, S.; Ródenas García, M.; Sánchez, P.; Muñoz, A.

    2013-06-01

    A microfluidic lab-on-a-chip derivatization technique has been developed to measure part per billion volume (ppbV) mixing ratios of gaseous glyoxal (GLY) and methylglyoxal (MGLY), and the method compared with other techniques in a smog chamber experiment. The method uses o-(2,3,4,5,6-pentafluorobenzyl) hydroxylamine (PFBHA) as a derivatization reagent and a microfabricated planar glass micro-reactor comprising an inlet, gas and fluid splitting and combining channels, mixing junctions, and a heated capillary reaction microchannel. The enhanced phase contact area-to-volume ratio and the high heat transfer rate in the micro-reactor result in a fast and highly efficient derivatization reaction, generating an effluent stream ready for direct introduction to a gas chromatograph-mass spectrometer (GC-MS). A linear response for GLY was observed over a calibration range 0.7 to 400 ppbV, and for MGLY of 1.2 to 300 ppbV, when derivatized under optimal reaction conditions. The method detection limits (MDLs) were 80 pptV and 200 pptV for GLY and MGLY respectively, calculated as 3 times the standard deviation of the S/N of the blank sample chromatograms. These MDLs are below or close to typical concentrations in clean ambient air. The feasibility of the technique was assessed by applying the methodology under controlled conditions to quantify of α-dicarbonyls formed during the photo-oxidation of isoprene in a large scale outdoor atmospheric simulation chamber (EUPHORE). Good general agreement was seen between microfluidic measurements and Fourier Transform Infra Red (FTIR), Broad Band Cavity Enhanced Absorption Spectroscopy (BBCEAS) and a detailed photochemical chamber box modelling calculation for both GLY and MGLY. Less good agreement was found with Proton-Transfer Reaction Time-of-Flight Mass Spectrometry (PTR-ToF-MS) and Solid Phase Microextraction (SPME) derivatization methods for MGLY measurement.

  18. Fail-safe ion chamber beam loss monitor system for personnel protection

    NASA Astrophysics Data System (ADS)

    Brown, D.; Plum, M. A.; Browman, A. A.; Macek, R. J.

    1999-01-01

    A fail-safe beam loss monitor system has been designed for use in the Los Alamos Neutron Scattering Center (LANSCE) Radiation Security System (RSS). The latest version (Model III) has been in use since 1991. This system has been carefully designed to protect personnel from large radiation doses caused by errant beam conditions during beam transport. Due to limited shielding between the beam transport lines and occupied areas, personnel can safely occupy these areas only if the beam losses in the transport lines are sufficiently low. Although the usual solution is to increase the bulk shielding between the beam lines and the occupied areas, the physical dimensions of the site do not permit additional shielding to be added. In this paper we will discuss the design and implementation of the fail-safe beam loss monitor system.

  19. Coke battery with 51-m{sup 3} furnace chambers and lateral supply of mixed gas

    SciTech Connect

    V.I. Rudyka; N.Y. Chebotarev; O.N. Surenskii; V.V. Derevich

    2009-07-15

    The basic approaches employed in the construction of coke battery 11A at OAO Magnitogorskii Metallurgicheskii Kombinat are outlined. This battery includes 51.0-m{sup 3} furnaces and a dust-free coke-supply system designed by Giprokoks with lateral gas supply; it is heated exclusively by low-calorific mixed gas consisting of blast-furnace gas with added coke-oven gas. The 82 furnaces in the coke battery are divided into two blocks of 41. The gross coke output of the battery (6% moisture content) is 1140000 t/yr.

  20. Real-time trend monitoring of gas compressor stations

    SciTech Connect

    Van Hardeveld, T. )

    1991-02-01

    The authors' company has developed a machinery health monitoring system (MHealth) for short-term and long-term historical trending and analysis of data from its 40 gas compressor stations. The author discusses the benefits of real-time trending in troubleshooting operations, in preventative maintenance scheduling and cites specific applications in the startup operations of several new gas compressor/centrifugal compressor units.

  1. Improved wire chamber

    DOEpatents

    Atac, M.

    1987-05-12

    An improved gas mixture for use with proportional counter devices, such as Geiger-Mueller tubes and drift chambers. The improved gas mixture provides a stable drift velocity while eliminating wire aging caused by prior art gas mixtures. The new gas mixture is comprised of equal parts argon and ethane gas and having approximately 0.25% isopropyl alcohol vapor. 2 figs.

  2. Software to Control and Monitor Gas Streams

    NASA Technical Reports Server (NTRS)

    Arkin, C.; Curley, Charles; Gore, Eric; Floyd, David; Lucas, Damion

    2012-01-01

    This software package interfaces with various gas stream devices such as pressure transducers, flow meters, flow controllers, valves, and analyzers such as a mass spectrometer. The software provides excellent user interfacing with various windows that provide time-domain graphs, valve state buttons, priority- colored messages, and warning icons. The user can configure the software to save as much or as little data as needed to a comma-delimited file. The software also includes an intuitive scripting language for automated processing. The configuration allows for the assignment of measured values or calibration so that raw signals can be viewed as usable pressures, flows, or concentrations in real time. The software is based on those used in two safety systems for shuttle processing and one volcanic gas analysis system. Mass analyzers typically have very unique applications and vary from job to job. As such, software available on the market is usually inadequate or targeted on a specific application (such as EPA methods). The goal was to develop powerful software that could be used with prototype systems. The key problem was to generalize the software to be easily and quickly reconfigurable. At Kennedy Space Center (KSC), the prior art consists of two primary methods. The first method was to utilize Lab- VIEW and a commercial data acquisition system. This method required rewriting code for each different application and only provided raw data. To obtain data in engineering units, manual calculations were required. The second method was to utilize one of the embedded computer systems developed for another system. This second method had the benefit of providing data in engineering units, but was limited in the number of control parameters.

  3. Use of UAVs for greenhouse gas monitoring at hotspot emissions zones

    NASA Astrophysics Data System (ADS)

    Pitt, J. R.; Allen, G.; Mead, M. I.; Hollingsworth, P.; Kabbabe, K.; Roberts, G.; Shallcross, D. E.

    2015-12-01

    Measuring greenhouse gas emissions from individual localised sources, or "hotspots", is important for both compliance monitoring and validating the techniques used to compile national emission inventories. Frequently ground based techniques are used, such as flux chamber measurements, which suffer from issues regarding sample representativeness, and tracer release methods, which for area sources rely heavily on release site configuration. Obtaining vertically resolved data can enable the use of a mass balance method to calculate greenhouse gas fluxes. This has been achieved using remote sensing techniques, but this usually requires the deployment of expensive, bulky instrumentation. Here we evaluate the suitability of using UAVs, in conjunction with emerging miniaturised sensor technology, as a highly manoeuvrable, low cost alternative for measuring hotspot greenhouse gas emissions. We describe a case study performed at a UK landfill site, where greenhouse gas measurements made on board a fixed wing UAV were used to estimate the bulk CH4 emission rate. Details of the mass balance technique employed, along with the key uncertainties associated with it, are discussed. This work is part of an ongoing study at the University of Manchester into the application of UAVs in atmospheric research, with the rapid advancement in miniaturised sensor technology providing new opportunities for integrating trace gas measurement with existing lightweight UAVs.

  4. Biological monitoring of isocyanates and related amines. IV. 2,4- and 2,6-toluenediamine in hydrolysed plasma and urine after test-chamber exposure of humans to 2,4- and 2,6-toluene diisocyanate.

    PubMed

    Brorson, T; Skarping, G; Sangö, C

    1991-01-01

    Two men were exposed to toluene diisocyanate (TDI) atmospheres at three different air concentrations (ca. 25, 50 and 70 micrograms/m3). The TDI atmospheres were generated by a gas-phase permeation method, and the exposures were performed in an 8-m3 stainless-steel test chamber. The effective exposure period was 4 h. The isomeric composition of the air in the test chamber was 30% 2,4-TDI and 70% 2,6-TDI. The concentration of TDI in air of the test chamber was determined by an HPLC method using the 9-(N-methyl-amino-methyl)-anthracene reagent and by a continuous-monitoring filter-tape instrument. Following the hydrolysis of plasma and urine, the related amines, 2,4-toluenediamine (2,4-TDA) and 2,6-toluenediamine (2,6-TDA), were determined as pentafluoropropionic anhydride (PFPA) derivatives by capillary gas chromatography using selected ion monitoring (SIM) in the electron-impact mode. In plasma, 2,4- and 2,6-TDA showed a rapid-phase elimination half-time of ca. 2-5 h, and that for the slow phase was greater than 6 days. A connection was observed between concentrations of 2,4- and 2,6-TDI in air and the levels of 2,4- and 2,6-TDA in plasma. The cumulated amount of 2,4-TDA excreted in the urine over 24 h was ca. 15%-19% of the estimated inhaled dose of 2,4-TDI, and that of 2,6-TDA was ca. 17%-23% of the inhaled dose of 2,6-TDI. A connection was found between the cumulated (24-h) urinary excretion of 2,4- and 2,6-TDA and the air concentration of 2,4- and 2,6-TDI in the test chamber.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:1660449

  5. Experimental study on engine gas-path component fault monitoring using exhaust gas electrostatic signal

    NASA Astrophysics Data System (ADS)

    Sun, Jianzhong; Zuo, Hongfu; Liu, Pengpeng; Wen, Zhenhua

    2013-12-01

    This paper presents the recent development in engine gas-path components health monitoring using electrostatic sensors in combination with signal-processing techniques. Two ground-based engine electrostatic monitoring experiments are reported and the exhaust gas electrostatic monitoring signal-based fault-detection method is proposed. It is found that the water washing, oil leakage and combustor linear cracking result in an increase in the activity level of the electrostatic monitoring signal, which can be detected by the electrostatic monitoring system. For on-line health monitoring of the gas-path components, a baseline model-based fault-detection method is proposed and the multivariate state estimation technique is used to establish the baseline model for the electrostatic monitoring signal. The method is applied to a data set from a turbo-shaft engine electrostatic monitoring experiment. The results of the case study show that the system with the developed method is capable of detecting the gas-path component fault in an on-line fashion.

  6. Analytical Modeling of Weld Bead Shape in Dry Hyperbaric GMAW Using Ar-He Chamber Gas Mixtures

    NASA Astrophysics Data System (ADS)

    Azar, Amin S.; Ås, Sigmund K.; Akselsen, Odd M.

    2013-03-01

    Hyperbaric arc welding is a special application of joining the pipeline steels under seawater. In order to analyze the behavior of the arc under ambient pressure, a model is required to estimate the arc efficiency. A distributed point heat source model was employed. The simulated isotherms were calibrated iteratively to fit the actual bead cross section. Basic gas mixture rules and models were used to calculate the thermal properties of the low-temperature shielding gas under the ambient pressure of 10 bar. Nine bead-on-plate welds were deposited each of which under different Ar-He chamber gas compositions. The well-known correlation between arc efficiency (delivered heat) and the thermal conductivity was established for different gas mixtures. The arc efficiency was considered separately for the transverse and perpendicular heat sources. It was found that assigning single heat efficiency factor for the entire arc, which is usually below unity, causes a noticeable underestimation for the heat transfer in the perpendicular direction and a little overestimation in the transverse direction.

  7. Flow chamber

    DOEpatents

    Morozov, Victor

    2011-01-18

    A flow chamber having a vacuum chamber and a specimen chamber. The specimen chamber may have an opening through which a fluid may be introduced and an opening through which the fluid may exit. The vacuum chamber may have an opening through which contents of the vacuum chamber may be evacuated. A portion of the flow chamber may be flexible, and a vacuum may be used to hold the components of the flow chamber together.

  8. Development of an online biosensor for in situ monitoring of chlorine dioxide gas disinfection efficacy.

    PubMed

    del Busto-Ramos, Maria; Budzik, Michael; Corvalan, Carlos; Morgan, Mark; Turco, Ronald; Nivens, David; Applegate, Bruce

    2008-03-01

    A prototype bioluminescence-based biosensor was designed and constructed to evaluate the antimicrobial efficacy of chlorine dioxide (ClO(2)) gas under various treatment conditions. The biosensor consisted of a bioluminescent bioreporter (Pseudomonas fluorescens 5RL), an optical transducer (photomultiplier tube), and a light-tight chamber housing, the bioreporter and the transducer. The bioluminescent recombinant P. fluorescens 5RL in the biosensor allowed for online monitoring of bioluminescence during ClO(2) gas disinfection. Experiments were performed to evaluate the effects of the two key physical parameters associated with ClO(2) disinfection: relative humidity (40, 60, 80%) and ClO(2) gas concentration (0.5, 1.0, 1.6, 2.1 mg/l) on the bioreporter. Results showed that increasing concentrations of ClO(2) gas corresponded to a faster decrease in luminescence. The rates of luminescence decrease from P. fluorescens 5RL, and the log reduction time (LRT, time required to obtain 1-log reduction in luminescence) were calculated for each treatment tested. The LRT values of luminescence were 103, 78, 53, and 35 s for 0.5, 1.0, 1.6, and 2.1 mg/l of ClO(2) gas treatment, respectively, at 78% relative humidity. The gas concentration which caused a tenfold change in LRT (z value) for luminescence of P. fluorescens 5RL was 3.4 mg/l of ClO(2). The prototype biosensor showed potential for many applications, such as monitoring real-time microbial inactivation and understanding parameters that influence the efficacy of gaseous decontamination procedures. PMID:18224317

  9. AN ADVANCED FLUE GAS MONITOR FOR SO2 - PHASE I

    EPA Science Inventory

    The development of an instrument for continuously monitoring SO2 levels in flue gas is proposed. The SO2 will be detected by means of an electrochemical sensor cell, which operates in a three-electrode potentiostatic mode. The proposed innovation is develop-ment of an advan...

  10. 30 CFR 70.1900 - Exhaust Gas Monitoring.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... Director of the Federal Register in accordance with 5 U.S.C. 552(a) and 1 CFR part 51. In addition, copies... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Exhaust Gas Monitoring. 70.1900 Section 70.1900 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR COAL MINE SAFETY AND...

  11. 30 CFR 70.1900 - Exhaust Gas Monitoring.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... Director of the Federal Register in accordance with 5 U.S.C. 552(a) and 1 CFR part 51. In addition, copies... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Exhaust Gas Monitoring. 70.1900 Section 70.1900 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR COAL MINE SAFETY AND...

  12. Hot-filament chemical vapor deposition chamber and process with multiple gas inlets

    DOEpatents

    Deng, Xunming; Povolny, Henry S.

    2004-06-29

    A thin film deposition method uses a vacuum confinement cup that employs a dense hot filament and multiple gas inlets. At least one reactant gas is introduced into the confinement cup both near and spaced apart from the heated filament. An electrode inside the confinement cup is used to generate plasma for film deposition. The method is used to deposit advanced thin films (such as silicon based thin films) at a high quality and at a high deposition rate.

  13. 21 CFR 870.4330 - Cardiopulmonary bypass on-line blood gas monitor.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Cardiopulmonary bypass on-line blood gas monitor... Cardiopulmonary bypass on-line blood gas monitor. (a) Identification. A cardiopulmonary bypass on-line blood gas monitor is a device used in conjunction with a blood gas sensor to measure the level of gases in the...

  14. 21 CFR 870.4330 - Cardiopulmonary bypass on-line blood gas monitor.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Cardiopulmonary bypass on-line blood gas monitor... Cardiopulmonary bypass on-line blood gas monitor. (a) Identification. A cardiopulmonary bypass on-line blood gas monitor is a device used in conjunction with a blood gas sensor to measure the level of gases in the...

  15. 21 CFR 870.4330 - Cardiopulmonary bypass on-line blood gas monitor.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Cardiopulmonary bypass on-line blood gas monitor... Cardiopulmonary bypass on-line blood gas monitor. (a) Identification. A cardiopulmonary bypass on-line blood gas monitor is a device used in conjunction with a blood gas sensor to measure the level of gases in the...

  16. 21 CFR 870.4330 - Cardiopulmonary bypass on-line blood gas monitor.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Cardiopulmonary bypass on-line blood gas monitor... Cardiopulmonary bypass on-line blood gas monitor. (a) Identification. A cardiopulmonary bypass on-line blood gas monitor is a device used in conjunction with a blood gas sensor to measure the level of gases in the...

  17. 21 CFR 870.4330 - Cardiopulmonary bypass on-line blood gas monitor.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Cardiopulmonary bypass on-line blood gas monitor... Cardiopulmonary bypass on-line blood gas monitor. (a) Identification. A cardiopulmonary bypass on-line blood gas monitor is a device used in conjunction with a blood gas sensor to measure the level of gases in the...

  18. Remote Real-Time Monitoring of Subsurface Landfill Gas Migration

    PubMed Central

    Fay, Cormac; Doherty, Aiden R.; Beirne, Stephen; Collins, Fiachra; Foley, Colum; Healy, John; Kiernan, Breda M.; Lee, Hyowon; Maher, Damien; Orpen, Dylan; Phelan, Thomas; Qiu, Zhengwei; Zhang, Kirk; Gurrin, Cathal; Corcoran, Brian; O’Connor, Noel E.; Smeaton, Alan F.; Diamond, Dermot

    2011-01-01

    The cost of monitoring greenhouse gas emissions from landfill sites is of major concern for regulatory authorities. The current monitoring procedure is recognised as labour intensive, requiring agency inspectors to physically travel to perimeter borehole wells in rough terrain and manually measure gas concentration levels with expensive hand-held instrumentation. In this article we present a cost-effective and efficient system for remotely monitoring landfill subsurface migration of methane and carbon dioxide concentration levels. Based purely on an autonomous sensing architecture, the proposed sensing platform was capable of performing complex analytical measurements in situ and successfully communicating the data remotely to a cloud database. A web tool was developed to present the sensed data to relevant stakeholders. We report our experiences in deploying such an approach in the field over a period of approximately 16 months. PMID:22163975

  19. Remote real-time monitoring of subsurface landfill gas migration.

    PubMed

    Fay, Cormac; Doherty, Aiden R; Beirne, Stephen; Collins, Fiachra; Foley, Colum; Healy, John; Kiernan, Breda M; Lee, Hyowon; Maher, Damien; Orpen, Dylan; Phelan, Thomas; Qiu, Zhengwei; Zhang, Kirk; Gurrin, Cathal; Corcoran, Brian; O'Connor, Noel E; Smeaton, Alan F; Diamond, Dermot

    2011-01-01

    The cost of monitoring greenhouse gas emissions from landfill sites is of major concern for regulatory authorities. The current monitoring procedure is recognised as labour intensive, requiring agency inspectors to physically travel to perimeter borehole wells in rough terrain and manually measure gas concentration levels with expensive hand-held instrumentation. In this article we present a cost-effective and efficient system for remotely monitoring landfill subsurface migration of methane and carbon dioxide concentration levels. Based purely on an autonomous sensing architecture, the proposed sensing platform was capable of performing complex analytical measurements in situ and successfully communicating the data remotely to a cloud database. A web tool was developed to present the sensed data to relevant stakeholders. We report our experiences in deploying such an approach in the field over a period of approximately 16 months. PMID:22163975

  20. Component greenhouse gas fluxes and radiative balance from two deltaic marshes in Louisiana: Pairing chamber techniques and eddy covariance

    USGS Publications Warehouse

    Krauss, Ken W.; Holm, Guerry O.; Perez, Brian C.; McWhorter, David E.; Cormier, Nicole; Moss, Rebecca; Johnson, Darren; Neubauer, Scott C; Raynie, Richard C

    2016-01-01

    Coastal marshes take up atmospheric CO2 while emitting CO2, CH4, and N2O. This ability to sequester carbon (C) is much greater for wetlands on a per-area basis than from most ecosystems, facilitating scientific, political, and economic interest in their value as greenhouse gas sinks. However, the greenhouse gas balance of Gulf of Mexico wetlands is particularly understudied. We describe the net ecosystem exchange (NEEc) of CO2 and CH4 using eddy covariance (EC) in comparison with fluxes of CO2, CH4, and N2O using chambers from brackish and freshwater marshes in Louisiana, USA. From EC, we found that 182 g C m-2 y-1 was lost through NEEc from the brackish marsh. Of this, 11 g C m-2 y-1 resulted from net CH4 emissions and the remaining 171 g C m-2 y-1 resulted from net CO2 emissions. In contrast, -290 g C m2 y-1 was taken up through NEEc by the freshwater marsh, with 47 g C m-2 y-1 emitted as CH4 and -337 g C m-2 y-1 taken up as CO2. From chambers, we discovered that neither site had large fluxes of N2O. Sustained-flux greenhouse gas accounting metrics indicated that both marshes had a positive (warming) radiative balance, with the brackish marsh having a substantially greater warming effect than the freshwater marsh. That net respiratory emissions of CO2 and CH4 as estimated through chamber techniques were 2-4 times different from emissions estimated through EC requires additional understanding of the artifacts created by different spatial and temporal sampling footprints between techniques.

  1. Two chamber reaction furnace

    DOEpatents

    Blaugher, R.D.

    1998-05-05

    A vertical two chamber reaction furnace is described. The furnace comprises a lower chamber having an independently operable first heating means for heating the lower chamber and a gas inlet means for admitting a gas to create an ambient atmosphere, and an upper chamber disposed above the lower chamber and having an independently operable second heating means for heating the upper chamber. Disposed between the lower chamber and the upper chamber is a vapor permeable diffusion partition. The upper chamber has a conveyor means for conveying a reactant there through. Of particular importance is the thallinating of long-length thallium-barium-calcium-copper oxide (TBCCO) or barium-calcium-copper oxide (BCCO) precursor tapes or wires conveyed through the upper chamber to thereby effectuate the deposition of vaporized thallium (being so vaporized as the first reactant in the lower chamber at a temperature between about 700 C and 800 C) on TBCCO or BCCO tape or wire (the second reactant) at its simultaneous annealing temperature in the upper chamber of about 800 to 950 C to thereby replace thallium oxide lost from TBCCO tape or wire because of the high annealing temperature or to deposit thallium on BCCO tape or wire. Continuously moving the tape or wire provides a single-step process that effectuates production of long-length TBCCO superconducting product. 2 figs.

  2. Two chamber reaction furnace

    DOEpatents

    Blaugher, Richard D.

    1998-05-05

    A vertical two chamber reaction furnace. The furnace comprises a lower chamber having an independently operable first heating means for heating the lower chamber and a gas inlet means for admitting a gas to create an ambient atmosphere, and an upper chamber disposed above the lower chamber and having an independently operable second heating means for heating the upper chamber. Disposed between the lower chamber and the upper chamber is a vapor permeable diffusion partition. The upper chamber has a conveyor means for conveying a reactant there through. Of particular importance is the thallinating of long-length thallium-barium-calcium-copper oxide (TBCCO) or barium-calcium-copper oxide (BCCO) precursor tapes or wires conveyed through the upper chamber to thereby effectuate the deposition of vaporized thallium (being so vaporized as the first reactant in the lower chamber at a temperature between about 700.degree. and 800.degree. C.) on TBCCO or BCCO tape or wire (the second reactant) at its simultaneous annealing temperature in the upper chamber of about 800.degree. to 950.degree. C. to thereby replace thallium oxide lost from TBCCO tape or wire because of the high annealing temperature or to deposit thallium on BCCO tape or wire. Continuously moving the tape or wire provides a single-step process that effectuates production of long-length TBCCO superconducting product.

  3. A Comparison of Eddy Covariance and Static Vented Chamber Measurements of Greenhouse Gas Flux in Mid-South US Rice

    NASA Astrophysics Data System (ADS)

    Reba, M. L.; Fong, B.; Adviento-Borbe, M. A.; Linquist, B.

    2015-12-01

    Rice (Oryza sativa) production in the Lower Mississippi River Basin constitutes over 75% of US rice production, but little research has been done on water and greenhouse gas (GHG) flux in this region at the field scale. Measurements of these fluxes were made in 2014 from a 26.3 ha drill-seeded rice (CL XL 753) field. Eddy covariance measurements of water and carbon dioxide (CO2) and methane (CH4) fluxes allow for an integrated field measurement of the interaction between the landscape and the atmosphere. A static vented chamber technique was also used to measure fluxes of CO2, N2O (nitrous oxide) and CH4 in the same field on 19 occasions during the rice growing season. Estimates of GHG flux using static vented chamber were compared with the GHG fluxes from the eddy covariance method. These findings begin to address the increased interest in understanding agricultural impact on net GHG emission and consumption in an understudied region of the US. Future research might include similar data collection from multiple fields where water management is varied to measure its impact on net GHG flux.

  4. [Research on improving sensitivity of the characteristic spectrum in micro-gas monitor].

    PubMed

    Sun, Yun-qiang; Lu, Xu-tao

    2010-07-01

    In order to realize the indoor micro noxious gas real-time monitor, and enhance measuring accuracy based on the characteristic spectrum examination method, a characteristic wavelengths filtration window was designed, in which the container is full with the highly concentrated testing gas. The container with the highly concentrated testing gas was used as the filtration window, the standard air as the reference window, the air chamber sufficient testing gas for testing density. The experiment demonstrated that using the WQF-520-FTIR infrared spectroscope to obtain the infrared absorption spectrum of dipropyl sebacate, there were mainly four characteristic wavelength lines: 3.385 26, 3.417.64, 5.797 11, and 8.561 65 microm, and the corresponding extinction was 1.520 0, 1.542 1, 2.431 8 and 1.352 6 respectively. The smallest content examined was 50 ppb, but using the characteristic wavelengths filtration window, the method could realize the 10(-4) nm magnitude alignment. The sensitivity was enhanced nearly 10 times, and the characteristic wavelengths filtration window method has the merits of high sensitivity, no discontinuity, real-time examination, and so on. PMID:20827993

  5. Measurement of greenhouse gas flux from agricultural soils using static chambers

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Measurement of greenhouse gas (GHG) fluxes between the soil and the atmosphere, in both managed and unmanaged ecosystems, is critical to understanding the biogeochemical drivers of climate change and to the development and evaluation of GHG mitigation strategies based on modulation of landscape mana...

  6. New generation enrichment monitoring technology for gas centrifuge enrichment plants

    SciTech Connect

    Ianakiev, Kiril D; Alexandrov, Boian S.; Boyer, Brian D.; Hill, Thomas R.; Macarthur, Duncan W.; Marks, Thomas; Moss, Calvin E.; Sheppard, Gregory A.; Swinhoe, Martyn T.

    2008-06-13

    The continuous enrichment monitor, developed and fielded in the 1990s by the International Atomic Energy Agency, provided a go-no-go capability to distinguish between UF{sub 6} containing low enriched (approximately 4% {sup 235}U) and highly enriched (above 20% {sup 235}U) uranium. This instrument used the 22-keV line from a {sup 109}Cd source as a transmission source to achieve a high sensitivity to the UF{sub 6} gas absorption. The 1.27-yr half-life required that the source be periodically replaced and the instrument recalibrated. The instrument's functionality and accuracy were limited by the fact that measured gas density and gas pressure were treated as confidential facility information. The modern safeguarding of a gas centrifuge enrichment plant producing low-enriched UF{sub 6} product aims toward a more quantitative flow and enrichment monitoring concept that sets new standards for accuracy stability, and confidence. An instrument must be accurate enough to detect the diversion of a significant quantity of material, have virtually zero false alarms, and protect the operator's proprietary process information. We discuss a new concept for advanced gas enrichment assay measurement technology. This design concept eliminates the need for the periodic replacement of a radioactive source as well as the need for maintenance by experts. Some initial experimental results will be presented.

  7. Note: Real-time monitoring via second-harmonic interferometry of a flow gas cell for laser wakefield acceleration.

    PubMed

    Brandi, F; Giammanco, F; Conti, F; Sylla, F; Lambert, G; Gizzi, L A

    2016-08-01

    The use of a gas cell as a target for laser wakefield acceleration (LWFA) offers the possibility to obtain stable and manageable laser-plasma interaction process, a mandatory condition for practical applications of this emerging technique, especially in multi-stage accelerators. In order to obtain full control of the gas particle number density in the interaction region, thus allowing for a long term stable and manageable LWFA, real-time monitoring is necessary. In fact, the ideal gas law cannot be used to estimate the particle density inside the flow cell based on the preset backing pressure and the room temperature because the gas flow depends on several factors like tubing, regulators, and valves in the gas supply system, as well as vacuum chamber volume and vacuum pump speed/throughput. Here, second-harmonic interferometry is applied to measure the particle number density inside a flow gas cell designed for LWFA. The results demonstrate that real-time monitoring is achieved and that using low backing pressure gas (<1 bar) and different cell orifice diameters (<2 mm) it is possible to finely tune the number density up to the 10(19) cm(-3) range well suited for LWFA. PMID:27587174

  8. Note: Real-time monitoring via second-harmonic interferometry of a flow gas cell for laser wakefield acceleration

    NASA Astrophysics Data System (ADS)

    Brandi, F.; Giammanco, F.; Conti, F.; Sylla, F.; Lambert, G.; Gizzi, L. A.

    2016-08-01

    The use of a gas cell as a target for laser wakefield acceleration (LWFA) offers the possibility to obtain stable and manageable laser-plasma interaction process, a mandatory condition for practical applications of this emerging technique, especially in multi-stage accelerators. In order to obtain full control of the gas particle number density in the interaction region, thus allowing for a long term stable and manageable LWFA, real-time monitoring is necessary. In fact, the ideal gas law cannot be used to estimate the particle density inside the flow cell based on the preset backing pressure and the room temperature because the gas flow depends on several factors like tubing, regulators, and valves in the gas supply system, as well as vacuum chamber volume and vacuum pump speed/throughput. Here, second-harmonic interferometry is applied to measure the particle number density inside a flow gas cell designed for LWFA. The results demonstrate that real-time monitoring is achieved and that using low backing pressure gas (<1 bar) and different cell orifice diameters (<2 mm) it is possible to finely tune the number density up to the 1019 cm-3 range well suited for LWFA.

  9. ULTRAHIGH SENSITIVITY HEAVY NOBLE GAS DETECTORS FOR LONG-TERM MONITORING AND MONITORING AIR

    EPA Science Inventory

    A Georgia Institute of Technology/Argonne National Laboratory team will develop and demonstrate novel ultrahigh sensitivity heavy noble gas (krypton, xenon, and radon) detectors for long-term monitoring of spent fuel and TRU waste, as well as for distinguishing background radon a...

  10. Modeling and validation of single-chamber microbial fuel cell cathode biofilm growth and response to oxidant gas composition

    DOE PAGESBeta

    Ou, Shiqi; Zhao, Yi; Aaron, Douglas S.; Regan, John M.; Mench, Matthew M.

    2016-08-15

    This work describes experiments and computational simulations to analyze single-chamber, air-cathode microbial fuel cell (MFC) performance and cathodic limitations in terms of current generation, power output, mass transport, biomass competition, and biofilm growth. Steady-state and transient cathode models were developed and experimentally validated. Two cathode gas mixtures were used to explore oxygen transport in the cathode: the MFCs exposed to a helium-oxygen mixture (heliox) produced higher current and power output than the group of MFCs exposed to air or a nitrogen-oxygen mixture (nitrox), indicating a dependence on gas-phase transport in the cathode. Multi-substance transport, biological reactions, and electrochemical reactions inmore » a multi-layer and multi-biomass cathode biofilm were also simulated in a transient model. The transient model described biofilm growth over 15 days while providing insight into mass transport and cathodic dissolved species concentration profiles during biofilm growth. Lastly, simulation results predict that the dissolved oxygen content and diffusion in the cathode are key parameters affecting the power output of the air-cathode MFC system, with greater oxygen content in the cathode resulting in increased power output and fully-matured biomass.« less