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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. 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

  4. 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.

  5. 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.

  6. 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...

  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. 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.

  9. Monitoring the Atmosphere in an Anaerobic Chamber

    PubMed Central

    Sudo, Sara Z.; Hersch, Paul A.

    1974-01-01

    The Couloximeter, a fuel cell designed to measure trace amounts of oxygen, was used to monitor the atmosphere in an anaerobic chamber. The device, easy to operate and to maintain, allowed both major and minor fluctuations in oxygen concentration to be measured. Using a hose attached to the outlet within the box, defective (ruptured) gloves were consistently distinguishable from intact gloves. PMID:16350004

  10. Gas Flow Simulation in GCB Chambers Featuring Hot Gas Energy

    NASA Astrophysics Data System (ADS)

    Mori, Tadashi; Iwamoto, Katsuharu; Kawano, Hiromichi; Tanaka, Yasunori

    A hot gas simulation in self-blast type GCBs was performed and revised. As a result, it was foundto be important to consider the thermodynamic and transport properties of SF6-PTFE gas at high pressures and temperatures. Moreover, modelling arc diameters are also important in the chamber. They have become the main factors in determining the rise of puffer pressure in self-blast type GCBs, while they were not relevant in conventional puffer-type GCBs.

  11. Gas feed system for the T-15 tokamak discharge chamber

    NASA Astrophysics Data System (ADS)

    Gulyaev, V. A.; Levkov, B. S.; Maslennikov, E. A.; Notkin, G. E.; Polkanov, V. N.; Shchedrov, V. M.

    Hydrogen (deuterium) and rare gas feed system for the T-15 tokamak discharge chamber is described. Fast-response pulsed piezovalve designs used in the gas feed system are presented. Problems of automated gas feed control, depending on discharge chamber wall gas saturation, diaphragm and plasma parameters, are considered.

  12. 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.

  13. Simple ``Package Design'' Ion Chamber Monitors for TRIUMF's Proton Beamlines

    NASA Astrophysics Data System (ADS)

    Gray, Daniel; Minato, Brian

    2002-12-01

    In the beam line designed to supply 100 μA of 500 MeV protons to the two ISAC production targets at TRIUMF, 13 profile monitor stations were required. The design allows each station to be fitted with either an air driven wire scanner module for high currents or an ionization chamber for low currents. Ring shaped multilayer G10 circuit boards were designed for the latter to enable a simple modular "gas package" that is easily serviced and aligned. These gas packages have only five basic parts, two outer window frames with 0.010 in. thick E-beam welded Al windows, two ring shaped circuit boards with 2 mm wire spacing and edge card connectors (X and Y use the same design of board) and one center frame for mounting to the inserting mechanism and holding a .001 in. Al foil. The circuit boards are critical components due to the necessity to hold vacuum along their edges. Signal traces pass from the inner part of the ring that is gas filled to the outside of the ring that is in vacuum. The windows and center foil frame are at -300 V bias. This gas package design led to a similar design used to upgrade the existing (1970's vintage) proton beamline ion chamber monitors.

  14. 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.

  15. Preliminary studies of a new monitor ionization chamber.

    PubMed

    Yoshizumi, Maíra T; Vivolo, Vitor; Caldas, Linda V E

    2010-01-01

    A new monitor ionization chamber was developed at Instituto de Pesquisas Energéticas e Nucleares (IPEN) in order to monitor X-ray beams. The main difference of this monitor ionization chamber in relation to other monitor chambers is its geometry, which consists of a ring-shaped sensitive volume. Because of this geometry, the monitor chamber has a central hole through which the direct radiation beam passes. The operational characteristics of the monitor chamber were evaluated: saturation, ion collection efficiency and polarity effect. Besides these tests, the short- and medium-term stabilities of its response were also evaluated. During the tests the leakage current was always negligible. All results showed values within those recommended internationally (IEC, 1997. Medical electrical equipment-dosimeters with ionization chambers and/or semi-conductor detectors as used in X-ray diagnostic imaging. IEC 61674. International Electrotechnical Commission, Genève). Copyright 2009 Elsevier Ltd. All rights reserved.

  16. 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

    ... 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, hot gas inlet chambers and all ductwork in which coal dust may accumulate shall be equipped with...

  17. 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.

  18. 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)

  19. Segmented ionization chambers for beam monitoring in hadrontherapy

    NASA Astrophysics Data System (ADS)

    Braccini, Saverio; Cirio, Roberto; Donetti, Marco; Marchetto, Flavio; Pittà, Giuseppe; Lavagno, Marco; La Rosa, Vanessa

    2015-05-01

    Segmented ionization chambers represent a good solution to monitor the position, the intensity and the shape of ion beams in hadrontherapy. Pixel and strip chambers have been developed for both passive scattering and active scanning dose delivery systems. In particular, strip chambers are optimal for pencil beam scanning, allowing for spatial and time resolutions below 0.1 mm and 1 ms, respectively. The MATRIX pixel and the Strip Accurate Monitor for Beam Applications (SAMBA) detectors are described in this paper together with the results of several beam tests and industrial developments based on these prototypes.

  20. 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.

  1. Microstrip gas chamber on thin-film Pestov glass and micro gap chamber

    SciTech Connect

    Gong, W.G.; Harris, J.W.; Wieman, H.

    1994-07-01

    The authors report developments of the Microstrip Gas Chamber on thin-film Pestov glass and the Micro Gap Chamber. By coating a thin-layer of low-resistive, electronically-conductive glass on various substrates (including quartz and ceramics), they built MSGCs of high gain stability and low leakage current. They were tested in Ar-CH{sub 4} (10%) and He-C{sub 2}H{sub 6} (50%) gas mixtures. Energy resolutions of 17-20% were measured for 6keV x-rays. This design can make the choice of substrate less important, save the cost of ion-implantation, and use less glass material. Micro Gap Chamber was successfully tested in He-C{sub 2}H{sub 6} (50%) and Ar-C{sub 2}H{sub 6}(50%) gas mixtures. Energy resolutions of about 20% were obtained. Both detectors are expected to have high rate capability.

  2. 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.

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

    USDA-ARS?s Scientific Manuscript database

    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...

  4. 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.

  5. 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.

  6. 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.

  7. 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.

  8. 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

  9. 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.

  10. 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.

  11. Fast Gas Replacement in Plasma Process Chamber by Improving Gas Flow Pattern

    NASA Astrophysics Data System (ADS)

    Morishita, Sadaharu; Goto, Tetsuya; Akutsu, Isao; Ohyama, Kenji; Ito, Takashi; Ohmi, Tadahiro

    2009-01-01

    The precise and high-speed alteration of various gas species is important for realizing precise and well-controlled multiprocesses in a single plasma process chamber with high throughput. The gas replacement times in the replacement of N2 by Ar and that of H2 by Ar are measured in a microwave excited high-density and low electron-temperature plasma process chamber at various working pressures and gas flow rates, incorporating a new gas flow control system, which can avoid overshoot of the gas pressure in the chamber immediately after the valve operation, and a gradational lead screw booster pump, which can maintain excellent pumping capability for various gas species including lightweight gases such as H2 in a wide pressure region from 10-1 to 104 Pa. Furthermore, to control the gas flow pattern in the chamber, upper ceramic shower plates, which have thousands of very fine gas injection holes (numbers of 1200 and 2400) formed with optimized allocation on the plates, are adopted, while the conventional gas supply method in the microwave-excited plasma chamber uses many holes only opened at the sidewall of the chamber (gas ring). It has been confirmed that, in the replacement of N2 by Ar, a short replacement time of approximately 1 s in the cases of 133 and 13.3 Pa and approximately 3 s in the case of 4 Pa can be achieved when the upper shower plate has 2400 holes, while a replacement time longer than approximately 10 s is required for all pressure cases where the gas ring is used. In addition, thanks to the excellent pumping capability of the gradational lead screw booster pump for lightweight gases, it has also been confirmed that the replacement time of H2 by Ar is almost the same as that of N2 by Ar.

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

    NASA Astrophysics Data System (ADS)

    Carroll, Thomas; Lack, Michael; Vineyard, Michael

    1997-04-01

    A control system for the drift-chamber gas system for the CEBAF Large Acceptance Spectrometer at the Thomas Jefferson National Accelerator Facility in Newport News, Virginia, has been developed with the Experimental Physics and Industrial Control System (EPICS). EPICS is a sophisticated software tool for building real-time, distributed control systems. The gas system includes three RS- 232 instruments. The gas flow is controlled and monitored with two MKS 647A Multigas Controllers. Pressures are measured with three MKS 146B Vacuum Gauge Measurement and Control Systems. The Panametrics Moisture Image Series 1 and 3 are used to monitor temperatures and the concentrations of oxygen, water, and ethane. Many parameters are also monitored with XYCOM XVME- 560 analog input cards. A discussion of the development of the RS-232 device support software and the control system will be presented.

  13. a Liquid Ionization Chamber as Monitor in Radiotherapy

    NASA Astrophysics Data System (ADS)

    Berghöfer, Th.; Engler, J.; Milke, J. M.; Hörandel, J. R.; Hartmann, G. H.

    2006-04-01

    First measurements with a prototype liquid ionization chamber are described to be applied as an online-monitor for intensity modulated radiotherapy. The detector consists of 480 individual electronic channels which allow parallel read-out of radiation induced currents at frequencies exceeding 10 Hz. Dose gradients in the direction of leaf movement of a multileaf collimator have been measured and a reconstruction method for individual leaf positions has been developed. The achieved reconstruction accuracy will be described.

  14. An automatic flux chamber for investigating gas flux at water - air interfaces

    NASA Astrophysics Data System (ADS)

    Duc, N. T.; Silverstein, S.; Lundmark, L.; Reyier, H.; Crill, P. M.; Bastviken, D.

    2011-12-01

    Aquatic ecosystems are major sources of greenhouse gases (GHG) and representative measurements of GHG fluxes from aquatic ecosystems to the atmosphere are vital in climate related biogeochemistry. One of the most important fluxes, ebullition (bubble flux) of methane (CH4) is episodic, with large fluxes during short time periods. To properly capture such fluxes long term measurement approaches are necessary which is labor intensive for manual flux chamber based methods, or require expensive equipment with e.g. eddy correlation methods. An inexpensive and easily mobile automatic flux chamber for long-term measurements has been designed to approach these drawbacks. This device includes a flux chamber, with a controller/datalogger, valves, a pump, a 12 V battery and a solar cell. Sensors used so far record CH4 concentration in the chamber headspace, temperature in water and air, barometric pressure. Other sensors for e.g. CO2 and weather variables can be attached. The unit can be programmed to measure in situ accumulation of gas in the chamber and also to collect gas samples in an array of sample bottles for subsequent analysis in the laboratory. Simultaneous deployment of many such units represent a cost efficient and easily managed solution for local long term flux monitoring.

  15. 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.

  16. PULSATION PHENOMENA DURING COMBUSTION OF NATURAL GAS IN COMBUSTION CHAMBERS OF GAS TURBINES,

    DTIC Science & Technology

    of convective heat transfer from the flame to the heat exchange surfaces. The tendency towards pulsed combustion within a chamber consuming natural ... gas increases with a decrease in the initial temperature of the air and with a decrease in pressure of the admitted gas. The article also reports the effects of different types of burners on the operation of turbines.

  17. 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.

  18. 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.

  19. 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.

  20. Prospects for high pressure imaging gas scintillation drift chambers

    NASA Technical Reports Server (NTRS)

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

    1992-01-01

    The current developmental status and future potential of a promising hard X-ray and gamma ray detector are presented: the high pressure xenon gas scintillation imaging drift chamber. A scheme for reading out the scintillation light waveshifting fibers, which allows operation at pressures at least as high as 20 atmospheres, is used. This technique combines excellent spatial resolution (approximately 200 rms allowing 1.5 arcminute mapping resolution), very good energy resolution (within a factor of three of Ge detectors), good time resolution (approximately 100 ns), and extremely high sensitivity because of excellent background rejection capabilities; it also offers possibilities for extrapolation to large area detectors. Results from tests with a prototype chamber are presented. The design of a scientific instrument for a balloon flight planned in 1995 is described. This instrument, the Scintillation Imaging Gas filled Hard X-ray Telescope (SIGHT), is optimized for detecting 30 to 300 keV X-rays. It has an active area of 1140 sq cm, with a stopping power of between 2.0 and 2.7 g/sq cm of xenon at 20 atmospheres. Possible future evolutionary tracks of the technology leading to innovative satellite applications are discussed.

  1. 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.

  2. 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.

  3. 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.

  4. 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.

  5. 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.

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

    USDA-ARS?s Scientific Manuscript database

    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...

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

    USDA-ARS?s Scientific Manuscript database

    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...

  9. Dimethylether: a low velocity, low diffusion drift chamber gas

    SciTech Connect

    Villa, F.

    1983-01-01

    There are two main motivations to look for a low electron mobility gas: the first is that a low drift velocity relaxes the need to measure drift times with nanosecond (or even subnanosecond) precision; the second is that (in an ideal drift geometry), the capability of resolving two closely spaced tracks depends upon the ratio of electron mobility to ion mobility ..mu../sub e//..mu../sub i/. Since ..mu../sub i/ is rather constant, the way to separate two tracks is to slow down the electrons. Many other properties are required besides low mobility and low drifting electron temperature: the gas should have a large (> 10/sup 3/) stable gain; it must be chemically stable and not oxic; it should not attack materials commonly used to fabricate drift chambers, etc. With these requirements in mind, we have tried a few promising (on paper) gases, either pure or in admixture with Argon. One of the gases examined, dimethylether ((CH/sub 3/)/sub 2/)), has shown interesting characteristics.

  10. 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

  11. 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.

  12. 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 Section 77.303 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR COAL MINE... COAL MINES Thermal Dryers § 77.303 Hot gas inlet chamber dropout doors. Thermal dryer systems which...

  13. 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 Section 77.303 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR COAL MINE... COAL MINES Thermal Dryers § 77.303 Hot gas inlet chamber dropout doors. Thermal dryer systems which...

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

    USDA-ARS?s Scientific Manuscript database

    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...

  15. Electret ion chamber radon monitors measure dissolved 222Rn in water.

    PubMed

    Kotrappa, P; Jester, W A

    1993-04-01

    This paper describes a simple and relatively inexpensive method of determining the concentration of dissolved 222Rn in water. The method involves a recently developed electret-passive environmental radon monitor, which uses an electret ion chamber. The procedure consists of sealing a known volume of a carefully collected water sample with one of these monitors in an exposure container and determining the average equilibrium 222Rn gas concentration in the air phase during the exposure time period. This average concentration can then be used to calculate the 222Rn concentration in the original water sample. Identical samples were analyzed both by this new method and by a standard liquid scintillation method, and the results were compared over a wide range of 222Rn concentrations. There was good agreement except that the electret ion chamber method gave results that were consistently lower by about 15%. This bias in the results was attributed to both 222Rn losses during sample handling and possibly to some errors in the assumptions made in the theoretical model. A correction factor is recommended to bring the results of this technique into agreement with the standard method. The procedures are simple and economical and can be easily employed by many primary 222Rn-measuring laboratories currently using these monitors for measuring indoor 222Rn.

  16. Design and performance of a dynaniic gas flux chamber.

    PubMed

    Reichman, Rivka; Rolston, Dennis E

    2002-01-01

    Chambers are commonly used to measure the emission of many trace gases and chemicals from soil. An aerodynamic (flow through) chamber was designed and fabricated to accurately measure the surface flux of trace gases. Flow through the chamber was controlled with a small vacuum at the outlet. Due to the design using fans, a partition plate, and aerodynamic ends, air is forced to sweep parallel and uniform over the entire soil surface. A fraction of the air flowing inside the chamber is sampled in the outlet. The air velocity inside the chamber is controlled by fan speed and outlet suction flow rate. The chamber design resulted in a uniform distribution of air velocity at the soil surface. Steady state flux was attained within 5 min when the outlet air suction rate was 20 L/min or higher. For expected flux rates, the presence of the chamber did not affect the measured fluxes at outlet suction rates of around 20 L/min, except that the chamber caused some cooling of the surface in field experiments. Sensitive measurements of the pressure deficit across the soil layer in conjunction with measured fluxes in the source box and chamber outlet show that the outflow rate must be controlled carefully to minimize errors in the flux measurements. Both over- and underestimation of the fluxes are possible if the outlet flow rate is not controlled carefully. For this design, the chamber accurately measured steady flux at outlet air suction rates of approximately 20 L/min when the pressure deficit within the chamber with respect to the ambient atmosphere ranged between 0.46 and 0.79 Pa.

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

    NASA Astrophysics Data System (ADS)

    Dölling, Rudolf

    2006-11-01

    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.

  18. Gas turbine structural mounting arrangement between combustion gas duct annular chamber and turbine vane carrier

    DOEpatents

    Wiebe, David J.; Charron, Richard C.; Morrison, Jay A.

    2016-10-18

    A gas turbine engine ducting arrangement (10), including: an annular chamber (14) configured to receive a plurality of discrete flows of combustion gases originating in respective can combustors and to deliver the discrete flows to a turbine inlet annulus, wherein the annular chamber includes an inner diameter (52) and an outer diameter (60); an outer diameter mounting arrangement (34) configured to permit relative radial movement and to prevent relative axial and circumferential movement between the outer diameter and a turbine vane carrier (20); and an inner diameter mounting arrangement (36) including a bracket (64) secured to the turbine vane carrier, wherein the bracket is configured to permit the inner diameter to move radially with the outer diameter and prevent axial deflection of the inner diameter with respect to the outer diameter.

  19. On the hot gas exhaustion in the exhaust chamber of a gas circuit breaker after short-circuit current interruption

    NASA Astrophysics Data System (ADS)

    Hayashi, Yasushi; Suzuki, Katsumi; Haginomori, Eiichi; Toda, Hiroaki; Ikeda, Hisatoshi

    1997-11-01

    The hot gas inside the exhaust chamber of a gas circuit breaker (GCB) is investigated after short-circuit current interruption. It is found that the exhausted hot gas generates a compression pressure wave. When the interrupting arc energy is low, the velocity of the hot gas is low and the hot gas is delayed relative to the pressure wave at the exit of the exhaust chamber. The interaction between the pressure wave and the hot gas is weak and the hot gas is found concentrated near the centre of the exhaust chamber. When the interrupting arc energy becomes high, the velocity of the hot gas becomes high and it is found that the hot gas area overlaps the area of increased pressure. The interaction between the pressure wave and the hot gas is strong, the hot gas density distribution becomes flat due to the pressure increase and the pressure increase is enhanced by the hot gas flow. The pressure increase clogs the exit of the exhaust chamber and the gas near the upstream area loses its dielectric strength.

  20. 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.

  1. Fast-burn combustion chamber design for natural gas engines

    SciTech Connect

    Evans, R.L.; Blaszczyk, J.

    1998-01-01

    The work presented in this paper compares the performance and emissions of the UBC Squish-Jet fast-burn combustion chamber with a baseline bowl-in-piston (BIP) chamber. It was found that the increased turbulence generated in the fastburn combustion chambers resulted in 5 to 10% faster burning of the air-fuel mixture compared to a conventional BIP chamber. The faster burning was particularly noticeable when operating with lean air-fuel mixtures. The study was conducted at a 1.7 mm clearance height and 10.2:1 compression ratio. Measurements were made over a range of air-fuel ratios from stoichiometric to the lean limit. At each operating point all engine performance parameters, and emissions of nitrogen oxides, unburned hydrocarbons, and carbon monoxide were recorded. At selected operating points a record of cylinder pressure was obtained and analyzed off-line to determine mass-burn rate in the combustion chamber. Two piston designs were tested at wide-open throttle conditions and 2000 rpm to determine the influence of piston geometry on the performance and emissions parameters. The UBC squish-jet combustion chamber design demonstrates significantly better performance parameters and lower emission levels than the conventional BIP design. Mass-burn fraction calculations showed a significant reduction in the time to burn the first 10% of the charge, which takes approximately half of the time to burn from 10 to 90% of the charge.

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

    USDA-ARS?s Scientific Manuscript database

    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...

  3. 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.

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

    USDA-ARS?s Scientific Manuscript database

    Previous analysis of chamber-based nitrous oxide (N2O) gas flux estimate errors has not considered the impacts of soil biological uptake and has not closely examined the influence of measurement error on resulting flux estimates. Simulation modeling is used here to demonstrate that chamber N2O conce...

  5. A two-dimensional position sensitive gas chamber with scanned charge transfer readout

    NASA Astrophysics Data System (ADS)

    Gómez, F.; Iglesias, A.; Lobato, R.; Mosquera, J.; Pardo, J.; Pena, J.; Pazos, A.; Pombar, M.; Rodríguez, A.

    2003-10-01

    We have constructed and tested a two-dimensional position sensitive parallel-plate gas ionization chamber with scanned charge transfer readout. The scan readout method described here is based on the development of a new position-dependent charge transfer technique. It has been implemented by using gate strips perpendicularly oriented to the collector strips. This solution reduces considerably the number of electronic readout channels needed to cover large detector areas. The use of a 25 μm thick kapton etched circuit allows high charge transfer efficiency with a low gating voltage, consequently needing a very simple commutating circuit. The present prototype covers 8×8 cm2 with a pixel size of 1.27×1.27 mm2. Depending on the intended use and beam characteristics a smaller effective pixel is feasible and larger active areas are possible. This detector can be used for X-ray or other continuous beam intensity profile monitoring.

  6. [Development of physiological monitors based on the Zigbee technology for hyperbaric oxygen chambers].

    PubMed

    Zheng, Jin-Nuan; Wu, Bao-Ming; Lin, Jin-Zhao; Wang, Qiang

    2008-05-01

    This paper introduces a monitor that can monitor five physiological parameters (ECG, blood pressure, spo2, respiration and temperature) based on Wireless Sensor Networks. The monitor will be applied to hyperbaric oxygen chambers. After acquisition, the signal will be displayed on the LCD screen of the monitor terminal in the cabin. At the same time, the Zigbee RF module will send the signal to the extravehicular guardianship PC terminals. This monitor equipment can realize synchronous real-time monitoring both inside and outside. What's more? A host can also display monitoring data the three monitor terminals collected. Preliminary clinical tests show that the monitors are safe and the monitoring results are satisfactory.

  7. 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.

  8. 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.

  9. 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.

  10. Study of swirling gas-dispersed flows in vortex chambers of various structures in the presence and absence of combustion

    NASA Astrophysics Data System (ADS)

    Volchkov, É. P.; Dvornikov, N. A.; Lukashov, V. V.; Borodulya, V. A.; Teplitskii, Yu. S.; Pitsukha, E. A.

    2012-07-01

    Consideration is given to swirling gas-dispersed flows in the cylindrical combustion chamber with a lateral swirler, in the conical combustion chamber with a nonflow bed of a dispersed material, and in the cylindrical combustion chamber with lower end injection of the gas through a slot swirler.

  11. Nuclear signal simulation applied to gas ionizing chambers

    SciTech Connect

    Coulon, Romain; Dumazert, Jonathan

    2015-07-01

    Particle transport codes used in detector simulation allow the calculation of the energy deposited by charged particles produced following an interaction. The pulses temporal shaping is more and more used in nuclear measurement into pulse shape analysis techniques. A model is proposed in this paper to simulate the pulse temporal shaping and the associated noise level thanks to the output track file PTRAC provides by Monte-Carlo particle transport codes. The model has been dedicated to ion chambers and more especially for High Pressure Xenon chambers HPXe where the pulse shape analysis can resolve some issues regarding with this technology as the ballistic deficit phenomenon. The model is fully described and an example is presented as a validation of such full detector simulation. (authors)

  12. Sensitivity and environmental response of the CMS RPC Gas Gain Monitoring system

    NASA Astrophysics Data System (ADS)

    Benussi, L.; Bianco, S.; Colafranceschi, S.; Fabbri, F. L.; Giardoni, M.; Ortenzi, B.; Passamonti, L.; Piccolo, D.; Pierluigi, D.; Ponzio, B.; Russo, A.; Saviano, G.; Colaleo, A.; Loddo, F.; Maggi, M.; Ranieri, A.; Abbrescia, M.; Iaselli, G.; Marangelli, B.; Natali, S.; Nuzzo, S.; Pugliese, G.; Romano, F.; Roselli, G.; Trentadue, R.; Tupputi, S.; Guida, R.; Polese, G.; Sharma, A.; Cimmino, A.; Lomidze, D.; Paolucci, D.; Baesso, P.; Necchi, M.; Pagano, D.; Ratti, S. P.; Vitulo, P.; Viviani, C.

    2009-08-01

    Results from the gas gain monitoring (GGM) system for the RPC muon detector in the CMS experiment at the LHC are presented. The system is designed to provide fast and accurate determination of any shift in the working point of the chambers due to gas mixture changes.

  13. Multi-Gas Monitor (MGM)

    NASA Technical Reports Server (NTRS)

    Pilgrim, Jeff; Limero, Thomas

    2015-01-01

    Multi-Gas Monitor is a flight experiment, a technology demonstration to test the ability of tunable diode laser spectroscopy based instrument to stay in calibration long term and follow events and dynamics occurring with the cabin atmosphere. MGM measures 4 gases: oxygen, carbon monoxide, ammonia and water vapor, as well as temperature and pressure. This month marked one year of successful and continuous MGM operation on ISS. The crew successfully tested the ammonia channel using a commercially available inhalant. MGM has detected some interesting dynamics inside Japanese Experiment Module (JEM) as a result of CO2 thruster firings from the SPHERES/RINGS payload and water spikes from dry out cycling of the JEM heat exchangers. Results to date have given us high confidence in the technology such that we believe this could have applications in the energy and medical sectors. This presentation will summarize the testing and results of the unit on ISS and suggest areas of use within the energy and medical arenas.

  14. A two-cell chamber for measuring gas exchange in tree seedlings

    Treesearch

    Keith F. Jensen; Frederick W. Bender; Roberta G. Masters

    1973-01-01

    A two-celled chamber for measuring gas exchange in tree seedlings is described. Temperature is controlled within ± 0.5º C by means of a copper coil. The two cells are independent of one another, and one cell can be used as a preconditioning cell while gas exchange measurements are being made in the second cell.

  15. 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.

  16. 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.

  17. 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.

  18. 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

    2014-08-03

    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.

  19. 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

  20. Cell culture chamber with gas supply for prolonged recording of human neuronal cells on microelectrode array.

    PubMed

    Kreutzer, Joose; Ylä-Outinen, Laura; Mäki, Antti-Juhana; Ristola, Mervi; Narkilahti, Susanna; Kallio, Pasi

    2017-03-15

    Typically, live cell analyses are performed outside an incubator in an ambient air, where the lack of sufficient CO2 supply results in a fast change of pH and the high evaporation causes concentration drifts in the culture medium. That limits the experiment time for tens of minutes. In many applications, e.g. in neurotoxicity studies, a prolonged measurement of extracellular activity is, however, essential. We demonstrate a simple cell culture chamber that enables stable culture conditions during prolonged extracellular recordings on a microelectrode array (MEA) outside an incubator. The proposed chamber consists of a gas permeable silicone structure that enables gas transfer into the chamber. We show that the culture chamber supports the growth of the human embryonic stem cell (hESC)-derived neurons both inside and outside an incubator. The structure provides very low evaporation, stable pH and osmolarity, and maintains strong signaling of hESC-derived neuronal networks over three-day MEA experiments. Existing systems are typically complex including continuous perfusion of medium or relatively large amount of gas to supply. The proposed chamber requires only a supply of very low flow rate (1.5ml/min) of non-humidified 5% CO2 gas. Utilizing dry gas supply makes the proposed chamber simple to use. Using the proposed culture structure on top of MEA, we can maintain hESC-derived neural networks over three days outside an incubator. Technically, the structure requires very low flow rate of dry gas supporting, however, low evaporation and maintaining the pH of the culture. Copyright © 2017 Elsevier B.V. All rights reserved.

  1. 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)

  2. 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)

  3. Electron attachment to oxygen, water, and methanol, in various drift chamber gas mixtures

    NASA Astrophysics Data System (ADS)

    Huk, M.; Igo-Kemenes, P.; Wagner, A.

    1988-04-01

    Attachment of electrons to oxygen, water, and methanol molecules has been studied in various gas mixtures based on argon, methane and isobutane, a class of gases often used to operate large drift chambers. The measurements were performed using a drift chamber in which the conditions prevailing in large experiments could be closely reproduced. Attachment coefficients were extracted as a function of the gas composition and pressure, the drift field, and the concentration of the molecules under investigation. The observed effects are compared to other measurements, and are discussed within the frame of physical models.

  4. Gas-laser power monitor

    NASA Technical Reports Server (NTRS)

    Russ, C. E., Jr.

    1981-01-01

    Device attaches simply to front of laser housing for continuous monitoring of power output. Monitor is calibrated to read either total output or power generated in test volume. It is fabricated from four black-anodized aluminum parts; crown glass positioned at Brewster angle reflects 0.33 percent of beam onto photodiode calibrated for electrical output proportional to laser power. Unlike conventional calorimeter, monitor does not interrupt laser beams, and fast-response diode allows instantaneous tracking of power fluctuations.

  5. A pixel chamber to monitor the beam performances in hadron therapy

    NASA Astrophysics Data System (ADS)

    Bonin, R.; Boriano, A.; Bourhaleb, F.; Cirio, R.; Donetti, M.; Garelli, E.; Giordanengo, S.; Marchetto, F.; Peroni, C.; Sanz Freire, C. J.; Simonetti, L.

    2004-03-01

    In this paper we describe the design, construction, and tests of a parallel plate ionization chamber with the anode segmented in (32×32) square pixels. The performance of the read out and data acquisition systems is also discussed. The design of the chamber has been finalized to be used as a beam monitor for therapeutical treatments. Position and flux resolution obtained with a carbon ion beam are presented.

  6. A method for measuring the electron drift velocity in working gas using a Frisch-grid ionization chamber

    NASA Astrophysics Data System (ADS)

    Bai, Huaiyong; Wang, Zhimin; Zhang, Luyu; Chen, Jinxiang; Zhang, Guohui

    2016-12-01

    A method for measuring the electron drift velocity in working gas is proposed. Based on the cathode and the anode signal waveforms of the Frisch-grid ionization chamber, the electron drift velocity is extracted. With this method, the electron drift velocities in Ar + 10% CH4, Ar + 3.5% CO2 and Kr + 2.7% CO2 gases have been measured and the results are compared with the existing measurements and the simulating results. Using this method, the electron drift velocity can be monitored throughout the experiment of charged particle without bothering the measurement of other parameters, such as the energy and orientation.

  7. Gas mixtures for quality control of the sTGC chambers

    NASA Astrophysics Data System (ADS)

    Filippov, K. A.; Konovalov, S. P.; Mikenberg, G.; Romaniouk, A.; Shchukin, D.; Shoa, M.; Smakhtin, V.; Smirnov, S. Yu; Sosnovtsev, V. V.; Teterin, P. E.; Tikhomirov, V. O.; Tsekhosh, V. I.; Vorobev, K. A.

    2016-02-01

    sTGC chambers are designed to operate at super-LHC conditions and will be installed in place during Phase-I upgrade of the ATLAS muon spectrometer. These chambers will provide precise coordinate measurements of the charged particle tracks and level 1 trigger for high pT muons. It is critical for the ATLAS detector to ensure a robust operation of these chambers during entire sLHC period. A quality control procedure based on X-ray scanner is being developed. Choice of the active gas for these tests is a very important issue. On one hand it should allow to find different types of chamber production defects, on the other hand one has to be sure that found problems are essential for the detector operation in future. Studies of the operation of the sTGC chamber prototype under X-ray irradiation with two gas mixtures (n- pentane/CO2 and CO2) were performed. The prototype was irradiated by X-rays with energy up to 50 keV. Particular attention was paid to the study of the “hot” chamber regions.

  8. Using field bus for optical gas monitoring

    NASA Astrophysics Data System (ADS)

    Cheng, Xiangyin; Seah, Leong K.; Ong, Lin S.; Asundi, Anand K.

    1999-05-01

    This paper presents a proposal for an optical gas monitoring system based on fieldbus. With the help of the advanced signal processing system more than one hundred gas detectors can be connected to a host system by a single shared bus cable over which the gas detectors, now incorporating with their own intelligence, communicate digitally with the host system. The new system supplies not only about the gas level but also about the physical condition of each sensor. Planed maintenance can be performed to ensure that gas monitor system is maintained in full working order. Integrating fieldbus with optical gas sensor will also have dramatic saving in field wiring and the man-hours for system verification and configuration.

  9. Measurements of backscattered radiation from Therac-20 collimator and trimmer jaws into beam monitor chamber.

    PubMed

    Kubo, H; Lo, K K

    1989-01-01

    The field size dependent photon output is known to be influenced by the existence of backscattered radiation (BSR) generated in the collimator or trimmer jaws of a linear accelerator. This paper describes the results of measurements made to study the existence of such backscatter by simulating the geometry of the treatment head of a Therac-20 linear accelerator. The machine's monitor chamber, flattening filter, and collimator jaws were simulated by another real monitor chamber, a 1-cm thick lead sheet and 2.5-cm thick low-melting-point alloy divergent blocks, respectively. BSR from the simulated collimator jaws (SCJ) was measured with the simulated monitor chamber (SMC) as a function of the openings of the SCJ and as a function of distance between SMC and SCJ. The present results demonstrate the presence of BSR in an 18-MV photon beam from a Therac-20 linear accelerator.

  10. Measurements of backscattered radiation from Therac-20 collimator and trimmer jaws into beam monitor chamber

    SciTech Connect

    Kubo, H.; Lo, K.K.

    1989-03-01

    The field size dependent photon output is known to be influenced by the existence of backscattered radiation (BSR) generated in the collimator or trimmer jaws of a linear accelerator. This paper describes the results of measurements made to study the existence of such backscatter by simulating the geometry of the treatment head of a Therac-20 linear accelerator. The machine's monitor chamber, flattening filter, and collimator jaws were simulated by another real monitor chamber, a 1-cm thick lead sheet and 2.5-cm thick low-melting-point alloy divergent blocks, respectively. BSR from the simulated collimator jaws (SCJ) was measured with the simulated monitor chamber (SMC) as a function of the openings of the SCJ and as a function of distance between SMC and SCJ. The present results demonstrate the presence of BSR in an 18-MV photon beam from a Therac-20 linear accelerator.

  11. A gas scintillation monitor for tritium gas in argon or in nitrogen.

    PubMed

    Campi, F; Mascherpa, C; Sterlini, C; Pacenti, P; Terrani, S

    1996-09-01

    For civilian purposes tritium is presently used in quantities of tens of PBq (MCi) in laboratories for the studies of tritium technology, at the Joint European Torus plant (Abingdon, Oxon, OX143A, UK) as fuel for the process of nuclear fusion, and in the manufacture of radio-luminescent items. Given the extreme mobility of tritium in most materials, it is necessary to use systems for double containment, such as glove boxes or spaces between primary and secondary containers, in which inert gas like argon or nitrogen flows. With these systems it is possible to recover tritium that escapes from the primary containment. Presently the gas flow is monitored continuously by means of ionization chambers which may present problems in particular applications ("memory effect" with high activity, strong dependence of the response on the presence of impurity, etc.). The aim of the work here presented is to determine the prospects for the realization of a new type of monitor mainly dedicated to the measurement of gas activity in isolation space of the containing systems of the high activity tritium plants. This monitor should have sufficient sensitivity, quick response, and should be easily decontaminated. As a detection technique we chose the scintillation produced in the inert gas by radioactive decay. With the first prototype, designed in cylindrical form, it was possible to observe gaseous scintillation events in mixture of tritium and argon or nitrogen. Following that, a spherical prototype was designed, of which we studied the performances and the dependence of the response varying the pressure, the concentration of tritium, the percentage of the impurity, and the gas flow rate. The results are satisfactory and suggest that the monitor could be used in glove boxes and double containment systems. The future research program will include tests involving large quantities of tritium and a study of the ideal dimensions and geometry of the detection chamber in order to optimize

  12. Air-based coal gasification in a two-chamber gas reactor with circulating fluidized bed

    NASA Astrophysics Data System (ADS)

    Dubinin, A. M.; Tuponogov, V. G.; Kagramanov, Y. A.

    2017-01-01

    During the bed gasification of solid fuels, the process temperature in the reaction zone is not high enough for reaching the maximum rate of the chemical efficiency factor of the gasification process. In order to increase the chemical efficiency factor, it is necessary to supply extra heat to the reaction zone to increase the reaction temperature. In this article, coal gasification in a chamber with forced fluidized bed is considered and it is proposed to supply extra heat with a circulating flow of an inert particulate heat transfer agent. Circulating inert particulate material is successively heated by coal combustion in a cone chamber with bubbling fluidized bed and in a combustion chamber with a spherical nozzle that inhibits the forced fluidized bed. After that, the heat transfer agent heated to 930-950°C enters first in a gasification chamber with bubbling bed and then in a chamber with forced fluidized bed, where it transfers the physical heat to the air fuel mixture. The experiments conducted with crushed Borodinsky coal and inert particulate heat transfer agent (electrocorundum) showed the temperature rise in a gasification chamber with from 760 to 870°C and the increase in the combustible component (CO) concentration in the gasification products by 5.5%. Based on the kinetic equations of the fuel combustion reactions and the CO2 reduction to CO and on the thermal balance equations of combustion and gasification chambers, the simulation model for the gas composition and the temperature rate calculated by the height of reaction chambers was developed. The experimental temperature rates and product gas compositions are in good agreement with the simulation results based on the proposed kinetic gasification model.

  13. 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.

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

    USDA-ARS?s Scientific Manuscript database

    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...

  15. Gas-well deliverability monitoring: Case histories

    SciTech Connect

    Thrasher, T.S.

    1995-08-01

    This paper presents practical techniques that can be used to monitor gas-well performance. These techniques, along with the routine examination of performance data, can help the engineer maintain production potential and extend well life. This paper demonstrates the importance of monitoring well performance on a regular basis through case history examples. Four types of well conditions are described: (1) deterioration in performance over time, (2) drainage area change, (3) liquid loading, and (4) tubing design constraint. This paper also discusses the use of a personal computer program as a tool to facilitate and encourage gas-well performance monitoring.

  16. 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.

  17. Numerical modeling of flow in a differential chamber of the gas-dynamic interface of a portable mass-spectrometer

    NASA Astrophysics Data System (ADS)

    Pivovarova, E. A.; Smirnovsky, A. A.; Schmidt, A. A.

    2013-11-01

    Mathematical modeling of flow in the differential chamber of the gas-dynamic interface of a portable mass-spectrometer was carried out to comprehensively study the flow structure and make recommendations for the optimization of the gas-dynamic interface. Modeling was performed using an OpenFOAM open computational platform. Conditions for an optimal operating mode of the differential chamber were determined.

  18. Evaluation of a detailed gas-phase atmospheric reaction mechanism using environmental chamber data

    NASA Astrophysics Data System (ADS)

    Carter, William P. L.; Lurmann, Fredrick W.

    This paper describes an evaluation of the performance of a detailed gas-phase reaction mechanism in simulating the results of 561 experiments carried out in four different environmental chambers. The experiments included background air, NO x-air, CONO x-air and aldehyde-air irradiations used for chamber characterization, NO x-air irradiations of single organics as well as simple and complex organic mixtures, and irradiations of auto exhaust. The methods used to represent the major chamber effects and the lighting characteristics in the model simulations of the experiments are described and their associated uncertainties are discussed. Statistical measures of the performance of the mechanism in simulating results of the various types of experiments are summarized and discussed. The mechanism was able to predict maximum ozone yields and rates of NO oxidation to within ±30% for 63% of the experiments modeled, and to within ±50% for 85% of the runs. There is a slight bias (˜15%) towards overprediction of ozone in mixture runs. Although there are cases where the simulations suggest possible problems with the gas-phase mechanism, much of the variability in the goodness of the fits could be attributed to uncertainties in chamber effects. It is concluded that better characterization of chamber conditions are needed if more comprehensive tests of atmospheric photochemical mechanisms are desired.

  19. Effects of inlet distortion on gas turbine combustion chamber exit temperature profiles

    NASA Astrophysics Data System (ADS)

    Maqsood, Omar Shahzada

    Damage to a nozzle guide vane or blade, caused by non-uniform temperature distributions at the combustion chamber exit, is deleterious to turbine performance and can lead to expensive and time consuming overhaul and repair. A test rig was designed and constructed for the Allison 250-C20B combustion chamber to investigate the effects of inlet air distortion on the combustion chamber's exit temperature fields. The rig made use of the engine's diffuser tubes, combustion case, combustion liner, and first stage nozzle guide vane shield. Rig operating conditions simulated engine cruise conditions, matching the quasi-non-dimensional Mach number, equivalence ratio and Sauter mean diameter. The combustion chamber was tested with an even distribution of inlet air and a 4% difference in airflow at either side. An even distribution of inlet air to the combustion chamber did not create a uniform temperature profile and varying the inlet distribution of air exacerbated the profile's non-uniformity. The design of the combustion liner promoted the formation of an oval-shaped toroidal vortex inside the chamber, creating localized hot and cool sections separated by 90° that appeared in the exhaust. Uneven inlet air distributions skewed the oval vortex, increasing the temperature of the hot section nearest the side with the most mass flow rate and decreasing the temperature of the hot section on the opposite side. Keywords: Allison 250, Combustion, Dual-Entry, Exit Temperature Profile, Gas Turbine, Pattern Factor, Reverse Flow.

  20. Additives That Prevent Or Reverse Cathode Aging In Drift Chambers With Helium-Isobutane Gas

    SciTech Connect

    Boyarski, Adam M.

    2001-11-20

    Noise and Malter breakdown have been studied at high rates in a test chamber having the same cell structure and gas as in the BaBar drift chamber. The chamber was first damaged by exposing it to a high source level at an elevated high voltage, until its operating current at normal voltages was below 0.5nA/cm. Additives such as water or alcohol allowed the damaged chamber to operate at 25 nA/cm, but when the additive was removed the operating point reverted to the original low value. However with 0.02% to 0.05% oxygen or 5% carbon dioxide the chamber could operate at more than 25 nA/cm, and continued to operate at this level even after the additive was removed. This shows for the first time that running with an O{sub 2} or CO{sub 2} additive at high ionization levels can cure a damaged chamber from breakdown problems.

  1. 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.

  2. Development of Local Gas Temperature Measurement Technique inside a Combustion Chamber Using Two-Wire Thermocouple

    NASA Astrophysics Data System (ADS)

    Kobayashi, Shigemi; Moriyoshi, Yasuo; Enomoto, Yoshiteru

    Thermocouples are widely used to measure the local gas temperature due to its accuracy and convenience. However, it is difficult to use thermocouples in a transient phenomenon such as reacting fields. In this study, the unsteady gas temperature inside a combustion chamber was measured by using an improved two-wire thermocouple technique. Based on previous two-wire methods, some modifications were examined. Firstly, numerical analysis of heat transfer between transient flow and thermocouple was performed to see what kind of modification was required. Secondly, a correction term was added to the basic equation, which was validated by experiments using a Rapid Compression and Expansion Machine. Finally, an improved two-wire thermocouple technique was evaluated by measuring the transient gas temperature inside a combustion chamber and compared to the estimated temperature using measured pressure data and assumptions of chemical equilibrium.

  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. 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.

  5. 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.

  6. 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.

  7. Development of a pixel ionization chamber for beam monitor in proton therapy

    NASA Astrophysics Data System (ADS)

    La Rosa, A.; Garella, M. A.; Attili, A.; Bourhaleb, F.; Cirio, R.; Donetti, M.; Giordanengo, S.; Givehchi, N.; Marchetto, F.; Mazza, G.; Meyroneinc, S.; Pecka, A.; Peroni, C.; Pittà, G.

    2007-03-01

    We have developed a detector to be used as monitor for proton therapy beam lines. The detector is a 2-D parallel plate ionization chamber, with the anode segmented in 1024 square pixels arranged in a 32×32 matrix. The detector characterization is presented.

  8. Evolved gas composition monitoring by repetitive injection gas chromatography.

    PubMed

    White, Robert L

    2015-11-20

    Performance characteristics and applications of a small volume gas chromatograph oven are described. Heating and cooling properties of the apparatus are evaluated and examples are given illustrating the advantages of greatly reducing the air bath volume surrounding fused silica columns. Fast heating and cooling of the oven permit it to be employed for repetitive injection analyses. By using fast gas chromatography separations to achieve short assay cycle times, the apparatus can be employed for on-line species-specific gas stream composition monitoring when volatile species concentrations vary on time scales of a few minutes or longer. This capability facilitates repeated sampling and fast gas chromatographic separations of volatile product mixtures produced during thermal analyses. Applications of repetitive injection gas chromatography-mass spectrometry evolved gas analyses to monitoring purge gas effluent streams containing volatile acid catalyzed polymer cracking products are described. The influence of thermal analysis and chromatographic experimental parameters on effluent sampling frequency are delineated. Copyright © 2015 Elsevier B.V. All rights reserved.

  9. Development and characterisation of a gas system and its associated slow-control system for an ATLAS small-strip thin gap chamber testing facility

    NASA Astrophysics Data System (ADS)

    Keyes, R.; Johnson, K. A.; Pepin, L.; Léger, F.; Qin, C.; Webster, S.; Robichaud-Véronneau, A.; Bélanger-Champagne, C.; Lefebvre, B.; Robertson, S. H.; Warburton, A.; Vachon, B.; Corriveau, F.

    2017-04-01

    A quality assurance and performance qualification laboratory was built at McGill University for the Canadian-made small-strip Thin Gap Chamber (sTGC) muon detectors produced for the 2019-2020 ATLAS experiment muon spectrometer upgrade. The facility uses cosmic rays as a muon source to ionise the quenching gas mixture of pentane and CO2 flowing through the sTGC detector. A gas system was developed and characterised for this purpose, with a simple and efficient gas condenser design utilizing a Peltier thermoelectric cooler (TEC). The gas system was tested to provide the desired 45 vol% pentane concentration. For continuous operations, a state-machine system was implemented with alerting and remote monitoring features to run all cosmic-ray data-acquisition associated slow-control systems, such as high/low voltage, gas system and environmental monitoring, in a safe and continuous mode, even in the absence of an operator.

  10. Leak rate estimation of a resistive plate chamber gap by monitoring absolute pressure

    NASA Astrophysics Data System (ADS)

    Mondal, S.; Datar, V. M.; Kalmani, S. D.; Majumder, G.; Mondal, N. K.; Satyanarayana, B.

    2016-11-01

    The differential pressure of a conventional manometer is highly dependent on the atmospheric pressure. The measurements with a manometer for an extended time period show a large variation due to solar atmospheric tides. However, the measurements of absolute pressure, both outside and inside of a resistive plate chamber (RPC), are independent of each other. By monitoring the absolute pressures, both outside and inside of a RPC, along with the temperature, its leakage rate can be estimated. During the test period, the supporting button spacers inside a RPC may get detached due to some manufacturing defect. This effect can be detected clearly by observing the sudden fall of pressure inside the chamber.

  11. Laboratory assessment of a flux chamber to determine landfill gas emissions

    SciTech Connect

    Gowing, A.; Farquhar, G.J.

    1997-12-31

    Landfill gas (LFG) is one of the by-products of decomposing municipal solid waste (MSW). The composition of LFG is approximately 50% V/V carbon dioxide and 50% V/V methane with a small percentage (generally less than 1%) of non-methane organic compounds (NMOCs). The LFG components contribute to ozone production, greenhouse gases, fire and explosive hazards, and the potential for cancer and other health problems. The flux chamber provides a nonintrusive technique which can be simple, accurate, and flexible for measuring real time emissions of the LFG components from the landfill surface. This research involved developing a flux chamber to be operated under different LFG flux conditions and different sweep gas flow rates. These parameters together with negative and positive pressure differentials were evaluated to determine the extent to which they affect LFG capture efficiencies. The flux chamber system was designed with a process controller attached to a pressure transducer and variable speed pump to regulate the pressure within chamber. The chamber was tested under laboratory conditions which included a multimedia, simulated landfill surface. A source of LFG was maintained below the simulated surface. The pressure control system was able to maintain average pressure differentials at values less than 0.04 mm H{sub 2}O under different LFG flux rates and sweep gas flow rates. Excellent capture efficiencies were achieved; capture ratios of expected to measured LFG flux rates through the soil surface ranged from 0.95 to 1.02 with an average of 0.99. Relatively small pressure differentials of {+-}1.8 mm H{sub 2}O reduced capture efficiency dramatically producing capture ratios ranging from 0.06 to 2.59.

  12. Initial test results of an ionization chamber shower detector for a LHC luminosity monitor

    SciTech Connect

    Datte, P.; Beche, J.-F.; Haguenauer, M.; Manfredi, P.F.; Manghisoni, M.; Millaud, J.; Placidi, M.; Ratti, L.; Riot, V.; Schmickler, H.; Speziali, V.; Turner, W.

    2002-11-05

    A novel, segmented, multi-gap, pressurized gas ionization chamber is being developed for optimization of the luminosity of the LHC. The ionization chambers are to be installed in the front quadrupole and zero degree neutral particle absorbers in the high luminosity IRs and sample the energy deposited near the maxima of the hadronic/electromagnetic showers in these absorbers. The ionization chambers are instrumented with low noise, fast, pulse shaping electronics to be capable of resolving individual bunch crossings at 40 MHz. In this paper we report the initial results of our second test of this instrumentation in an SPS external proton beam. Single 300 GeV protons are used to simulate the hadronic/electromagnetic shower produced by the forward collision products from the interaction regions of the LHC. The capability of instrumentations to measure the luminosity of individual bunches in a 40 MHz bunch train is demonstrated.

  13. High resolution gas ionization chamber in proportional mode for low energy applications

    NASA Astrophysics Data System (ADS)

    Müller, Arnold Milenko; Döbeli, Max; Synal, Hans-Arno

    2017-09-01

    The operation of the ETH gas ionization detector as a proportional chamber, where a secondary ionization avalanche is initiated between the Frisch grid and anode, was investigated for ions covering the mass range from H to 127I. By amplifying the detector electron signal through secondary ionization, the limitations due to the sensitivity of the detector electronics are minimized. It could be demonstrated that in the energy range of a few hundreds of keV and below a proportional chamber clearly outperforms a conventionally used gas ionization detector. Protons below 10 keV were measured with a resolution better than 1.4 keV and a good linearity of the particle energy and detector signal was found in the energy range between 50 and 1000 keV. At higher energies almost no difference in resolution for the two operation modes could be found.

  14. Eco-friendly gas mixtures for Resistive Plate Chambers based on tetrafluoropropene and Helium

    NASA Astrophysics Data System (ADS)

    Abbrescia, M.; Benussi, L.; Piccolo, D.; Bianco, S.; Ferrini, M.; Muhammad, S.; Passamonti, L.; Pierluigi, D.; Piccolo, D.; Primavera, F.; Russo, A.; Saviano, G.

    2016-08-01

    Due to the recent restrictions deriving from the application of the Kyoto protocol, the main components of the gas mixtures presently used in the Resistive Plate Chambers systems of the LHC experiments will be most probably phased out of production in the coming years. Identifying possible replacements with the adequate characteristics requires an intense R&D activity, which was recently started, in collaborations with various experiments. Possible new gases have been proposed and are thoroughly investigated. Some tests on one of the most promising candidate—HFO-1234ze, an allotropic form of tetrafluoropropane—have already been reported. Here an innovative approach, based on the use of Helium, to solve the problem related to the high operating voltage needed to operate the chambers with HFO-1234ze based gas mixtures, is discussed and the first results are shown.

  15. Gas monitoring onboard ISS using FTIR spectroscopy

    NASA Astrophysics Data System (ADS)

    Gisi, Michael; Stettner, Armin; Seurig, Roland; Honne, Atle; Witt, Johannes; Rebeyre, Pierre

    2017-06-01

    In the confined, enclosed environment of a spacecraft, the air quality must be monitored continuously in order to safeguard the crew's health. For this reason, OHB builds the ANITA2 (Analysing Interferometer for Ambient Air) technology demonstrator for trace gas monitoring onboard the International Space Station (ISS). The measurement principle of ANITA2 is based on the Fourier Transform Infrared (FTIR) technology with dedicated gas analysis software from the Norwegian partner SINTEF. This combination proved to provide high sensitivity, accuracy and precision for parallel measurements of 33 trace gases simultaneously onboard ISS by the precursor instrument ANITA1. The paper gives a technical overview about the opto-mechanical components of ANITA2, such as the interferometer, the reference Laser, the infrared source and the gas cell design and a quick overview about the gas analysis. ANITA2 is very well suited for measuring gas concentrations specifically but not limited to usage onboard spacecraft, as no consumables are required and measurements are performed autonomously. ANITA2 is a programme under the contract of the European Space Agency, and the air quality monitoring system is a stepping stone into the future, as a precursor system for manned exploration missions.

  16. 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.

  17. Upgrade to the Cryogenic Hydrogen Gas Target Monitoring System

    NASA Astrophysics Data System (ADS)

    Slater, Michael; Tribble, Robert

    2013-10-01

    The cryogenic hydrogen gas target at Texas A&M is a vital component for creating a secondary radioactive beam that is then used in experiments in the Momentum Achromat Recoil Spectrometer (MARS). A stable beam from the K500 superconducting cyclotron enters the gas cell and some incident particles are transmuted by a nuclear reaction into a radioactive beam, which are separated from the primary beam and used in MARS experiments. The pressure in the target chamber is monitored so that a predictable isotope production rate can be assured. A ``black box'' received the analog pressure data and sent RS232 serial data through an outdated serial connection to an outdated Visual Basic 6 (VB6) program, which plotted the chamber pressure continuously. The black box has been upgraded to an Arduino UNO microcontroller [Atmel Inc.], which can receive the pressure data and output via USB to a computer. It has been programmed to also accept temperature data for future upgrade. A new computer program, with updated capabilities, has been written in Python. The software can send email alerts, create audible alarms through the Arduino, and plot pressure and temperature. The program has been designed to better fit the needs of the users. Funded by DOE and NSF-REU Program.

  18. Experience with landfill gas monitoring and assessment

    SciTech Connect

    Jenness, S.R.; Wilcox, G.J.

    1998-12-31

    Landfills have recently come under additional environmental scrutiny for their potential as air emission sources. This paper discusses an air monitoring program that was performed in 1997 for the landfill located at US Army Fort Dix, New Jersey. Results of the program are presented as well as conclusions that were drawn from the sampling data and the sampling techniques employed. The Fort Dix Landfill air monitoring program consisted of quarterly measurements of gas vent (more than 50) flow rates. Flow rates were measured twice per day (morning and afternoon) with vane anemometers in order to assess diurnal effects. Measurements of ambient pressure and temperature were also taken for correlation with the gas vent flow rates. Additional gas sampling was performed on selected vents at the landfill to ascertain fixed gases (methane, carbon dioxide, oxygen, and nitrogen) content, total non-methane organic compounds (NMOC), hydrogen sulfide (H{sub 2}S) content, mercury content, and over sixty individual volatile organic compounds (VOCs).

  19. 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

  20. 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.

  1. Integrating volcanic gas monitoring with other geophysical networks in Iceland

    NASA Astrophysics Data System (ADS)

    Pfeffer, Melissa A.

    2017-04-01

    differences between erupted volumes and the inferred volume change of magma chambers. We will describe two recent examples of integrated monitoring in Iceland 1) syn-eruptive gas and deformation measurements used to simulate the subsurface properties of the magma from the 2014-2015 eruption of Bárðarbunga and 2) hydrological, seismic, and gas measurements made during the 2014 Sólheimajökull jökulhlaup used to discriminate between magmatic and hydrothermal origin of the flood and to perform a frequency analysis of past minor hydrothermal jökulhlaups.

  2. AXEL : Neutrinoless double beta decay search with a high pressure xenon gas Time Projection Chamber

    NASA Astrophysics Data System (ADS)

    Ban, Sei; AXEL collaboration

    2017-09-01

    AXEL is a high pressure xenon gas TPC detector being developed for neutrinoless double-beta decay search. It is operated at the proportional scintillation mode. We have developed 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 to reduce background. The project is in a R&D phase, and we report the current status of our prototype chamber with 10 L and 4 bar Xe gas.

  3. Modeling of natural acoustic frequencies of a gas-turbine plant combustion chamber

    NASA Astrophysics Data System (ADS)

    Zubrilin, I. A.; Gurakov, N. I.; Zubrilin, R. A.; Matveev, S. G.

    2017-05-01

    The paper presents results of determination of natural acoustic frequencies of a gas-turbine plant annular combustion chamber model using 3D-simulation. At the beginning, a calculation procedure for determining natural acoustic frequencies of the gas-turbine plant combustion chamber was worked out. The effect of spatial inhomogeneity of the flow parameters (fluid composition, pressure, temperature) arising in combustion and some geometrical parameters (cooling holes of the flame tube walls) on the calculation results is studied. It is found that the change of the fluid composition in combustion affects the acoustic velocity not more than 5%; therefore, the air with a volume variable temperature can be taken as a working fluid in the calculation of natural acoustic frequencies. It is also shown that the cooling holes of the flame tube walls with diameter less than 2 mm can be neglected in the determination of the acoustic modes in the frequency range of up to 1000 Hz. This reduces the number of the grid-model elements by a factor of six in comparison with a model that considers all of the holes. Furthermore, a method of export of spatial inhomogeneity of the flow parameters from a CFD solver sector model to the annular combustion chamber model in a modal solver is presented. As a result of the obtained model calculation, acoustic modes of the combustion chamber in the frequency range of up to 1000 Hz are determined. For a standard engine condition, a potentially dangerous acoustic mode with a frequency close to the ripple frequency of the precessing vortex core, which is formed behind the burner device of this combustion chamber, is detected.

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

    NASA Astrophysics Data System (ADS)

    Quentmeyer, Richard J.; Roncace, Elizabeth A.

    1993-07-01

    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.

  5. 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.

  6. 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

  7. Comparative evaluation of gas-turbine engine combustion chamber starting and stalling characteristics for mechanical and air-injection

    NASA Technical Reports Server (NTRS)

    Dyatlov, I. N.

    1983-01-01

    The effectiveness of propellant atomization with and without air injection in the combustion chamber nozzle of a gas turbine engine is studied. Test show that the startup and burning performance of these combustion chambers can be improved by using an injection during the mechanical propellant atomization process. It is shown that the operational range of combustion chambers can be extended to poorer propellant mixtures by combined air injection mechanical atomization of the propellant.

  8. 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.

  9. Test of freonless operation of resistive plate chambers with glass electrodes— 1 mm gas gap vs 2 mm gas gap

    NASA Astrophysics Data System (ADS)

    Sakaue, H.; Nakano, E.; Takahashi, T.; Teramoto, Y.

    2002-04-01

    Non-freon gas mixtures (Ar/iso-C 4H 10) were tested as the chamber gas for 1 and 2 mm gas gap Resistive Plate Chambers (RPCs) with float glass as the resistive electrodes, operated in the streamer mode. With the narrower ( 1 mm) gas gap, streamer charge is reduced (˜1/3), which reduces the dead time (and dead area), associated with each streamer, improving the detection efficiency. The best performance was obtained for two cases: Ar/iso-C 4H 10=50/50 and 60/40. For the 50/50 mixture, a detection efficiency of better than 98% was obtained for the 1 mm gap RPC, while the efficiency was 95% for the 2 mm gap RPC, each operated as a double-gap RPC. The measured time resolution (rms) was 1.45±0.05 (2.52±0.09) ns for the 1 (2) mm gap RPC for the 50/50 mixture.

  10. 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.

  11. 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.

  12. Pulsating combustion of gas fuel in the combustion chamber with closed resonant circuit

    NASA Astrophysics Data System (ADS)

    Yallina, E. V.; Larionov, V. M.; Iovleva, O. V.

    2013-12-01

    In the combustion chambers of the pulsation of gas flow oscillation greatly accelerate heat dissipation to the walls of the combustion chamber and improve combustion efficiency as compared with a uniform combustion mode. This allows you to effectively solve a number of problems of industrial power, including an environmentally friendly combustion products. Significant drawback of such systems - the emitted noise exceeding the permissible requirements. One solution to this problem - the separation of the resonance tube into 2 parts connected at the output to the interference of sound waves. The results of theoretical studies pulsating combustion technical mixture of propane in the system, consisting of a combustion chamber and two resonance tubes forming a closed resonant circuit. Resonators have a variable length. Calculations have shown that under certain oscillation of the resonator length to the first resonant frequency of the system is achieved by reducing SPL more than 15 dB. For oscillations at a second resonant frequency is the complete elimination of noise while maintaining intense oscillations in the combustion chamber.

  13. A new environmental chamber for evaluation of gas-phase chemical mechanisms and secondary aerosol formation

    NASA Astrophysics Data System (ADS)

    Carter, William P. L.; Cocker, David R.; Fitz, Dennis R.; Malkina, Irina L.; Bumiller, Kurt; Sauer, Claudia G.; Pisano, John T.; Bufalino, Charles; Song, Chen

    A new state-of-the-art indoor environmental chamber facility for the study of atmospheric processes leading to the formation of ozone and secondary organic aerosol (SOA) has been constructed and characterized. The chamber is designed for atmospheric chemical mechanism evaluation at low reactant concentrations under well-controlled environmental conditions. It consists of two collapsible 90 m 3 FEP Teflon film reactors on pressure-controlled moveable frameworks inside a temperature-controlled enclosure flushed with purified air. Solar radiation is simulated with either a 200 kW Argon arc lamp or multiple blacklamps. Results of initial characterization experiments, all carried out at ˜300-305 K under dry conditions, concerning NO x and formaldehyde offgasing, radical sources, particle loss rates, and background PM formation are described. Results of initial single organic-NO x and simplified ambient surrogate-NO x experiments to demonstrate the utility of the facility for mechanism evaluation under low NO x conditions are summarized and compared with the predictions of the SAPRC-99 chemical mechanism. Overall, the results of the initial characterization and evaluation indicate that this new environmental chamber can provide high quality mechanism evaluation data for experiments with NO x levels as low as ˜2 ppb, though the results indicate some problems with the gas-phase mechanism that need further study. Initial evaluation experiments for SOA formation, also carried out under dry conditions, indicate that the chamber can provide high quality secondary aerosol formation data at relatively low hydrocarbon concentrations.

  14. A xenon gas purity monitor for EXO

    NASA Astrophysics Data System (ADS)

    Dobi, A.; Hall, C.; Herrin, S.; Odian, A.; Prescott, C. Y.; Rowson, P. C.; Ackerman, N.; Aharmin, B.; Auger, M.; Barbeau, P. S.; Barry, K.; Benitez-Medina, C.; Breidenbach, M.; Cook, S.; Counts, I.; Daniels, T.; DeVoe, R.; Dolinski, M. J.; Donato, K.; Fairbank, W.; Farine, J.; Giroux, G.; Gornea, R.; Graham, K.; Gratta, G.; Green, M.; Hagemann, C.; Hall, K.; Hallman, D.; Hargrove, C.; Karelin, A.; Kaufman, L. J.; Kuchenkov, A.; Kumar, K.; Lacey, J.; Leonard, D. S.; LePort, F.; Mackay, D.; MacLellan, R.; Mong, B.; Montero Díez, M.; Müller, A. R.; Neilson, R.; Niner, E.; O'Sullivan, K.; Piepke, A.; Pocar, A.; Pushkin, K.; Rollin, E.; Sinclair, D.; Slutsky, S.; Stekhanov, V.; Twelker, K.; Voskanian, N.; Vuilleumier, J.-L.; Wichoski, U.; Wodin, J.; Yang, L.; Yen, Y.-R.

    2011-12-01

    We discuss the design, operation, and calibration of two versions of a xenon gas purity monitor (GPM) developed for the EXO double beta decay program. The devices are sensitive to concentrations of oxygen well below 1 ppb at an ambient gas pressure of one atmosphere or more. The theory of operation of the GPM is discussed along with the interactions of oxygen and other impurities with the GPM's tungsten filament. Lab tests and experiences in commissioning the EXO-200 double beta decay experiment are described. These devices can also be used on other noble gases.

  15. 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.

  16. 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.

  17. 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.

  18. Energy resolution in a high-pressure gas scintillation proportional chamber.

    PubMed

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

    1986-01-01

    A high-pressure gas scintillation proportional chamber has been designed and constructed to image x and gamma rays for medical applications. The chamber contains 4 atm of pure xenon. Ultraviolet light emitted from excited xenon atoms within the detector is collected by a hexagonal array of seven UV-sensitive photomultiplier tubes, which in turn are separated from the pressurized gas by 1-cm-thick fused-silica windows. A model was used to predict the energy resolution of the device as a function of fill-gas pressure, voltage within the detector, and light-collection efficiency. The energy resolution improved with increasing scintillation region voltage from 17% full width at half maximum (FWHM) at 1.9 kV to 10% FWHM at 3.0 kV for 59.5-keV photons; once above 1.5 kV, there was no improvement with increasing drift voltage. The addition of the signals from the peripheral phototubes to that of the center phototube did not substantially improve the energy resolution of the device. This was because the noise that was present yielded a high correlation between the phototubes; when this noise was incorporated into the model, the energy resolution of the multiphototube system was accurately estimated. The energy resolution of the gas scintillation proportional chamber was found to be superior to the sodium iodide Anger camera at 59.5 keV by a factor of 2. Further improvement can be obtained by increasing the scintillation region voltage and by increasing the light-collection efficiency by moving the scintillation region closer to the phototubes.

  19. Numerical evaluation of static-chamber measurements of soil-atmospheric gas exchange--Identification of physical processes

    USGS Publications Warehouse

    Healy, Richard W.; Striegl, Robert G.; Russell, Thomas F.; Hutchinson, Gordon L.; Livingston, Gerald P.

    1996-01-01

    The exchange of gases between soil and atmosphere is an important process that affects atmospheric chemistry and therefore climate. The static-chamber method is the most commonly used technique for estimating the rate of that exchange. We examined the method under hypothetical field conditions where diffusion was the only mechanism for gas transport and the atmosphere outside the chamber was maintained at a fixed concentration. Analytical and numerical solutions to the soil gas diffusion equation in one and three dimensions demonstrated that gas flux density to a static chamber deployed on the soil surface was less in magnitude than the ambient exchange rate in the absence of the chamber. This discrepancy, which increased with chamber deployment time and air-filled porosity of soil, is attributed to two physical factors: distortion of the soil gas concentration gradient (the magnitude was decreased in the vertical component and increased in the radial component) and the slow transport rate of diffusion relative to mixing within the chamber. Instantaneous flux density to a chamber decreased continuously with time; steepest decreases occurred so quickly following deployment and in response to such slight changes in mean chamber headspace concentration that they would likely go undetected by most field procedures. Adverse influences of these factors were reduced by mixing the chamber headspace, minimizing deployment time, maximizing the height and radius of the chamber, and pushing the rim of the chamber into the soil. Nonlinear models were superior to a linear regression model for estimating flux densities from mean headspace concentrations, suggesting that linearity of headspace concentration with time was not necessarily a good indicator of measurement accuracy.

  20. 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

  1. 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.

  2. Neurological manifestation of arterial gas embolism following standard altitude chamber flight: a case report.

    PubMed

    Rios-Tejada, F; Azofra-Garcia, J; Valle-Garrido, J; Pujante Escudero, A

    1997-11-01

    In the course of a decompression at flight level 280 (28,000 ft) in an altitude chamber flight, a 45-yr-old cabin air traffic controller developed sudden numbness in his left upper and lower extremities and, soon after, complete paralysis in the left side, dysarthria and left facial palsy. A presumptive diagnosis of arterial gas embolism (AGE) was made and hyperbaric oxygen therapy (HBO) was given after airevac of the patient to the closest compression facility. Complete resolution of the symptoms was obtained after treatment Table VI-A (extended), plus 3 consecutive HBO treatments (90 min of Oxygen at 2.0 ATA). AGE is a rare event in the course of regular altitude chamber flight and diagnosis should be done in the context of the barometric pressure changes and an acute cerebral vascular injury. Risk factors and follow-up diagnostic procedures are discussed.

  3. 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.

  4. Development of a peristaltic gas micropump with a single chamber and multiple electrodes

    NASA Astrophysics Data System (ADS)

    Lee, K. S.; Kim, B.; Shannon, M. A.

    2013-09-01

    This paper reports on the development of a multi-electrode electrostatically driven peristaltic gas micropump. The micropump consists of a single chamber and a flexible diaphragm with a multi-electrode pattern. The single-chamber design is divided into smaller cells by the electrodes; the characteristic operating frequency of the micropump increases as the number of electrodes increases. The flow rate is also observed to increase to maximum before decreasing for larger numbers of electrodes. Whereas the maximum flow rate of a 4-electrode micropump is about 40 µl min-1 at 14 Hz, the maximum flow rate of the 16-electrode micropump is about 250 µl min-1 at 1400 Hz and that of the 32-electrode micropump is 150 µl min-1 at 4000 Hz.

  5. Pulmonary fluid overload monitoring in heart failure patients with single and dual chamber defibrillators.

    PubMed

    Molon, Giulio; Zanotto, Gabriele; Rahue, Werner; Facchin, Domenico; Leoni, Loira; Morani, Giovanni; Calvi, Valeria; Catanzariti, Domenico; Costa, Alessandro; Zago, Lara; Comisso, Jennifer; Varbaro, Annamaria; Santini, Massimo

    2014-04-01

    Heart failure has a relevant healthcare impact. Monitoring of pulmonary fluid overload (PFO), measured by intrathoracic impedance, has been proposed to alert to heart failure worsening before symptoms become patent. The aim of our research was to evaluate whether PFO diagnostics reduce heart failure hospitalizations in heart failure patients receiving single-chamber or dual-chamber implantable cardioverter-defibrillator (ICD) for primary prevention of sudden death. Twenty-five Italian cardiological centers prospectively followed 221 ICD patients (86% men, 66 ± 11 years, 79% New York Heart Association II and left ventricular ejection fraction 28 ± 5%), of whom 123 received an ICD with PFO monitoring (diagnostics group) and 98 an ICD without such a diagnostics (control group). The association of each patient to a group was assigned a priori, independently of patients' characteristics but based on regional device allocation policies. Patient clinical characteristics and observation period were similar between groups. In a mean follow-up of 17 ± 11 months, heart failure hospitalizations or emergency-room admissions occurred in eight (7%) patients of the diagnostics group and in 16 of the control group (16%; P = 0.02), with an incidence, measured by Kaplan-Meier analysis, of 23% at 2 years and 34% at 3 years in patients of the control group compared with 8% at 2 and 3 years in patients of the diagnostics group (Log rank test P = 0.044). Our data show that in heart failure patients receiving single-chamber or dual-chamber ICD, the use of intrathoracic impedance monitoring is associated with a significant reduction of heart failure hospitalizations. Our results support the hypothesis that PFO diagnostics improve the likelihood of timely detection of heart failure worsening.

  6. Numerical simulations of flue gas flow in a first stage filter with top inlet - Modifications of the inlet chamber inserts

    NASA Astrophysics Data System (ADS)

    Novák, Martin; Matas, Richard; Sedláček, Jan

    2017-09-01

    This paper is focused on flue gas flow simulations in a first stage filter with top inlet that is used in a cogeneration power plant. CFD simulations were done with emphasize on the influence of inlet chamber on the flue gas distribution and filtering process. The flow has to be turned at right direction in a quite small space. To achieve this change, distribution walls with flaps and duct inserts are used in the inlet chamber. The results showed that the main influence on the velocity distribution inside the filter have the inserts in the chamber.

  7. A closed-chamber method to measure greenhouse gas fluxes from dry aquatic sediments

    NASA Astrophysics Data System (ADS)

    Lesmeister, Lukas; Koschorreck, Matthias

    2017-06-01

    Recent research indicates that greenhouse gas (GHG) emissions from dry aquatic sediments are a relevant process in the freshwater carbon cycle. However, fluxes are difficult to measure because of the often rocky substrate and the dynamic nature of the habitat. Here we tested the performance of different materials to seal a closed chamber to stony ground both in laboratory and field experiments. Using on-site material consistently resulted in elevated fluxes. The artefact was caused both by outgassing of the material and production of gas. The magnitude of the artefact was site dependent - the measured CO2 flux increased between 10 and 208 %. Errors due to incomplete sealing proved to be more severe than errors due to non-inert sealing material.Pottery clay as sealing material provided a tight seal between the chamber and the ground and no production of gases was detected. With this approach it is possible to get reliable gas fluxes from hard-substrate sites without using a permanent collar. Our test experiments confirmed that CO2 fluxes from dry aquatic sediments are similar to CO2 fluxes from terrestrial soils.

  8. 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

  9. 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.

  10. 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.

  11. 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.

  12. Determination of liquid-fuel prevaporization and premixing in gas-turbine combustion chambers

    NASA Astrophysics Data System (ADS)

    Mrugalla, J.

    A semiempirical mathematical model of the evaporation and distribution of liquid fuel in the prevaporization-premixing zone of a stationary gas turbine is developed, and the predictions obtained are compared with published experimental data and with the results of photographic, suction-probe, two-focus-laser-velocimeter, and light-scattering measurements on water sprays from 65-deg hollow-cone nozzles in a wind tunnel operating at 64 m/s. Good agreement is obtained, and the applicability of the model to the design of turbine combustion chambers giving lower NO(x) and CO emissions is indicated.

  13. Gas scintillation drift chambers with wave shifter read-out for hard X-ray astronomy

    NASA Technical Reports Server (NTRS)

    Sadoulet, Bernard; Lin, Robert P.; Weiss, Steven C.

    1987-01-01

    A major improvement in hard X-ray and gamma ray astrophysics could be provided by high pressure xenon time projection chambers where gas scintillation is used both for the measurement of the time of interaction and for the detection of the extracted electrons. This allows three dimensional imaging of naturally complex events (photoelectric interaction with escape photon, Compton scatter, and pair production). A novel read-out system based on wave shifter fibers, which is well suited to the high pressures and large areas required of a hard X-ray telescope is proposed. Expected performances are computed, potential problems are outlined, and the experimental effort to solve these problems are described.

  14. 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

  15. 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.

  16. Potential Magma Chambers beneath the Tatun Volcanic Area, Taiwan: Results from Magnetotelluric Survey and Monitoring

    NASA Astrophysics Data System (ADS)

    Chen, C.

    2013-12-01

    Previous earthquakes analysis indicated existing seismicity anomaly beneath Tatun volcano, Taiwan, possibly caused by the fluid activity of the volcano. Helium isotope studies also indicated that over 60% of the fumarolic gases and vapors originated from deep mantle in the Tatun volcano area. The chemistry of the fumarolic gases and vapors and seismicity anomaly are important issues in view of possible magma chamber in the Tatun volcano, where is in the vicinity of metropolitan Taipei, only 15 km north of the capital city. In this study magnetotelluric (MT) soundings and monitoring were deployed to understand the geoelectric structures in the Tatun volcano as Electromagnetic methods are sensitive to conductivity contrasts and can be used as a supplementary tool to delineate reservoir boundaries. An anticline extending more than 10 km beneath the Chih-Shin-Shan and Da-You-Kan areas was recognized. Low resistivity at a shallow and highly porous layer 500m thick might indicate circulation of heated water. However, a high resistivity layer at depth between 2 and 6 km was detected. This layer could be associated with high micro-earthquakes zone. The characteristics of this layer produced by either the magma chamber or other geothermal activity were similar to that of some other active volcanic areas in the world. At 6 km underground was a dome structure of medium resistivity. This structure could be interpreted as a magma chamber in which the magma is possibly cooling down, as judged by its relatively high resistivity. The exact attributes of the magma chamber were not precisely determined from the limited MT soundings. At present, a joint monitors including seismic activity, ground deformation, volcanic gases, and changes in water levels and chemistry are conducted by universities and government agencies. When unusual activity is detected, a response team may do more ground surveys to better determine if an eruption is likely.

  17. 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.

  18. 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.; Verwilligen, 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.

  19. Effects of a temporary HDPE cover on landfill gas emissions: multiyear evaluation with the static chamber approach at an Italian landfill.

    PubMed

    Capaccioni, Bruno; Caramiello, Cristina; Tatàno, Fabio; Viscione, Alessandro

    2011-05-01

    According to the European Landfill Directive 1999/31/EC and the related Italian Legislation ("D. Lgs. No. 36/2003"), monitoring and control procedures of landfill gas emissions, migration and external dispersions are clearly requested. These procedures could be particularly interesting in the operational circumstance of implementing a temporary cover, as for instance permitted by the Italian legislation over worked-out landfill sections, awaiting the evaluation of expected waste settlements. A possible quantitative approach for field measurement and consequential evaluation of landfill CO(2), CH(4) emission rates in pairs consists of the static, non-stationary accumulation chamber technique. At the Italian level, a significant and recent situation of periodical landfill gas emission monitoring is represented by the sanitary landfill for non-hazardous waste of the "Fano" town district, where monitoring campaigns with the static chamber have been annually conducted during the last 5 years (2005-2009). For the entire multiyear monitoring period, the resulting CO(2), CH(4) emission rates varied on the whole up to about 13,100g CO(2) m(-2)d(-1) and 3800 g CH(4) m(-2)d(-1), respectively. The elaboration of these landfill gas emission data collected at the "Fano" case-study site during the monitoring campaigns, presented and discussed in the paper, gives rise to a certain scientific evidence of the possible negative effects derivable from the implementation of a temporary HDPE cover over a worked-out landfill section, notably: the lateral migration and concentration of landfill gas emissions through adjacent, active landfill sections when hydraulically connected; and consequently, the increase of landfill gas flux velocities throughout the reduced overall soil cover surface, giving rise to a flowing through of CH(4) emissions without a significant oxidation. Thus, these circumstances are expected to cause a certain increase of the overall GHG emissions from the given

  20. 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.

  1. 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.

  2. 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.

  3. 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.

  4. Matrix:. AN Innovative Pixel Ionization Chamber for On-Line Beam Monitoring in Hadrontherapy

    NASA Astrophysics Data System (ADS)

    Braccini, S.; Pitta', G.; Donetti, M.; Cirio, R.; La Rosa, A.; Garella, M. A.; Giordanengo, S.; Marchetto, F.; Peroni, C.

    2006-04-01

    The control of intensity, position and shape of clinical beams are key issues in the treatment of tumours using hadron beams, especially in the case of active dose distribution systems. For this purpose an innovative pixel ionization chamber, named MATRIX, has been designed, constructed and tested. The chamber is conceived to be located very near the patient to precisely monitor the beam parameters used to verify the treatment planning specifications. MATRIX operates in air and is characterized by a 21 × 21 cm2 sensitive area subdivided in 1024 pixels of 6.5 × 6.5 mm2. To minimize the amount of material crossed by the beam, the anode is made of a 50 μm kapton foil, with a deposit of 17 μm copper on each side. A very sensitive electronics is used for the readout, based on a dedicated chip. In this paper the construction of the chamber and the very positive results of the first beam tests are described.

  5. Dynamics of the water molecule density in a discharge chamber filled with a low-pressure humid gas

    SciTech Connect

    Bernatskiy, A. V. Ochkin, V. N.; Bafoev, R. N.; Antipenkov, A. B.

    2016-10-15

    The dynamics of the H{sub 2}O molecule density in a metal gas-discharge chamber filled with low-pressure water vapor or its mixtures with noble gases was investigated by manometric and spectral methods. Regimes both with and without discharge excitation were studied. In the absence of a discharge, the molecule density dynamics is governed by the heterogeneous interaction of molecules with the chamber walls. In the presence of a discharge, in addition to the heterogeneous interaction, fast plasmachemical molecule dissociation also contributes to the initial stage of H{sub 2}O molecule loss. The role of heating of the chamber walls is discussed.

  6. A high rate proportional chamber

    SciTech Connect

    Henderson, R.; Fraszer, W.; Openshaw, R.; Sheffer, G.; Salomon, M.; Dew, S.; Marans, J.; Wilson, P.

    1987-02-01

    Gas mixtures with high specific ionization allow the use of small interelectrode distances while still maintaining full efficiency. With the short electron drift distances the timing resolution is also improved. The authors have built and operated two 25 cm/sup 2/ chambers with small interelectrode distances. Also single wire detector cells have been built to test gas mixture lifetimes. Various admixtures of CF/sub 4/, DME, Isobutane, Ethane and Argon have been tested. Possible applications of such chambers are as beam profile monitors, position tagging of rare events and front end chambers in spectrometers.

  7. How to overpressurize a magmatic chamber: the thermodynamic constraints of crystallization-gas exsolution processes

    NASA Astrophysics Data System (ADS)

    Cichy, S.; Thiéry, R.

    2012-12-01

    The pressure evolution of magmatic chambers is a key question in order to understand the triggering mechanisms and conditions of volcanic eruptions. While this subject is undoubtedly complex, a first answer was provided by the seminal model of Tait et al. (1989), which addresses the pressurization produced by simultaneous crystallization-gas exsolution. Through a set of simple equations, they succeed to tackle this problem by using salient physico-chemical parameters of interest, i.e. magma nature (mafic or felsic), bulk volatile content (H2O and CO2), crystallization variation, initial magma pressure, Henry solubility coefficients, elasticity of the magmatic chamber, melt and crystal densities. Thus, Tait et al. (1989) were able to show that coeval crystallization-gas exsolution is, indeed, an efficient process: a partial crystallization of a few percent in water-saturated magmas is sufficient to generate overpressures exceeding twice the tensile strength of the magmatic chamber. However, in other cases (CO2 or some H2O-CO2 saturated magmas), this model predicts underpressures of the magma chambers, and such a result is counterintuitive and problematic from what is known in volcanology. In fact, to our knowledge, one feature of the theory of Tait et al. has never been clearly stated in the literature: this model applies only in the case of disequilibrium growth of crystals in the magma, as no provision is made to take into account the chemical equilibrium of silicate components between solids and melt. While this simplification hypothesis is certainly valid in fast-evolving magmas (kinetic effects) it may be questioned in the case of slow crystallization at equilibrium with the melt. Thus, we have extended the algorithm of Tait et al. (1989) to deal with this new aspect. The main result is that, in all cases, significant overpressures will be generated in cooling magmas (even CO2-saturated magmas). This can be explained as follows: under the equilibrium assumption

  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. 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.

  10. 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

  11. Photoelectron range limitations to the spatial resolution for x-rays in gas proportional chambers

    SciTech Connect

    Smith, G.C.; Fischer, J.; Radeka, V.

    1983-11-01

    Measurements have been made, for x-ray energies from a few keV to 18 keV, of the limiting spatial resolution caused by the finite range of the photoelectron, or electrons, created when an x-ray is absorbed in the gas of a proportional chamber. In hydrocarbon gases such as methane and ethane, where the photoelectron receives the bulk of the x-ray energy, the limiting spatial resolution is found to vary as a power law of x-ray energy. In argon and xenon, at an x-ray energy approximately twice that of the A/sub K/ edge and the Xe/sub L/ edge respectively, the measured limiting resolution is better than expected from an equivalent power law behavior.

  12. SU-E-T-156: Can Sr-90 Check Sources Replace Co-60 Measurements for Monitoring of Reference Chamber Stability?

    SciTech Connect

    McEwen, M; Niven, D; Miksys, N

    2015-06-15

    Purpose: To determine the ultimate precision of a system for monitoring reference-class ion chamber stability using a commercial Sr-90 check source. Methods: A detailed investigation of a commercial Sr-90 check source (PTW48002) was carried out using a series of Farmer-type ionization chambers. Investigations included: positioning repeatability (angular variation as chamber is rotated in source, variation in ionization current with vertical alignment); chamber settling; short and long term repeatability Results: i) Measurement precision – the ionization current was typically 10 pA, and therefore a high-precision electrometer is required to prevent electrometer noise/resolution/leakage biaising the results. ii) Chamber settling - the chamber response stabilizes after approximately 10 minutes, which is longer than reported for linac beams and is likely due to the low doserate of the source.iii) The measured response depended at the 1 % level on the orientation of the chamber with respect to the source. However, consistent positioning resulted in repeatability at the 0.05 % level. Care was also required to ensure that the chamber was consistently positioned vertically with respect to the source. The sensitivity to vertical position was found to be > 1 % per mm.iv)With a uniform procedure the long-term (> 6 month) repeatability was found to be better than 0.1 % for multiple chamber types and potentially a precision of 0.05 % is achievable. Conclusion: A Sr-90 check source is easy to use and is a viable alternative to Co-60 for monitoring reference chamber stability.

  13. 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.

  14. 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.

  15. 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.

  16. 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.

  17. 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.

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

    DOEpatents

    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. Flame kernel characterization of laser ignition of natural gas-air mixture in a constant volume combustion chamber

    NASA Astrophysics Data System (ADS)

    Srivastava, Dhananjay Kumar; Dharamshi, Kewal; Agarwal, Avinash Kumar

    2011-09-01

    In this paper, laser-induced ignition was investigated for compressed natural gas-air mixtures. Experiments were performed in a constant volume combustion chamber, which simulate end of the compression stroke conditions of a SI engine. This chamber simulates the engine combustion chamber conditions except turbulence of air-fuel mixture. It has four optical windows at diametrically opposite locations, which are used for laser ignition and optical diagnostics simultaneously. All experiments were conducted at 10 bar chamber pressure and 373 K chamber temperature. Initial stage of combustion phenomena was visualized by employing Shadowgraphy technique using a high speed CMOS camera. Flame kernel development of the combustible fuel-air mixture was investigated under different relative air-fuel ratios ( λ=1.2-1.7) and the images were interrogated for temporal propagation of flame front. Pressure-time history inside the combustion chamber was recorded and analyzed. This data is useful in characterizing the laser ignition of natural gas-air mixture and can be used in developing an appropriate laser ignition system for commercial use in SI engines.

  20. 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.

  1. 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.

  2. The magic cube and the pixel ionization chamber: detectors for monitor and dosimetry of radiotherapy beams

    NASA Astrophysics Data System (ADS)

    Amerio, S.; Boriano, A.; Bourhaleb, F.; Cirio, R.; Donetti, M.; Garelli, E.; Giordanengo, S.; Madon, E.; Marchetto, F.; Nastasi, U.; Peroni, C.; Sanz Freire, C. J.; Sardo, A.; Trevisiol, E.

    2003-09-01

    Tumor therapy takes advantage of the energy deposition of radiation to concentrate high doses in the target while sparing healthy tissue. Elective pathologies for highly conformal radiotherapies such as photon Intensity Modulated Radiotherapy (IMRT) and radiotherapy with hadrons are head and neck, eye, prostate and in general all tumors that are either deep or located close to critical organs. In the world there are several centers that are using such techniques and a common problem that is being experienced is the verification of treatment plans and monitoring of the beam. We have designed and built two detectors that allow 2D and 3D measurements of dose and fluence of such beams. The detectors allow measurements on big surfaces, up to 25∗25 cm2. The active media are parallel plate, strip and pixel segmented ionization chambers with front-end Very Large Scale Integration (VLSI) readout and PC based data acquistion. The description of dosimeter, chamber and electronics will be given with results from beam tests and therapy plan verification.

  3. Waste gas monitor reduces wasted volatile anesthetic.

    PubMed

    Euliano, T Y; van Oostrom, J H; van der Aa, J

    1999-07-01

    The increasing focus on health care costs requires that all physicians evaluate practice behaviors. The primary emphasis in anesthesia has been limiting the use of expensive medications and interventions. Reducing waste is another approach, and volatile anesthetics are an appropriate target in that simple reduction of fresh gas-flow (FGF) rates is effective. A monitor that measures and displays the cost of wasted volatile anesthetic was developed and used to determine if real-time display of the cost would result in decreased FGF rates, which, in turn, would decrease wasted anesthetic. The waste gas monitor (WGM) measures flow rate at the anesthesia machine's scavenger port, integrates this with agent concentration, and displays the calculated cost, real-time, on a portable computer screen. The WGM equipment was attached to the anesthesia machine in the gynecologic surgery operating room (OR) and those cases performed under general endotracheal anesthesia and lasting longer than one hour were eligible for inclusion. First year anesthesiology residents assigned to the study OR as part of a non-specialty rotation, were the subjects of the study. For each resident, after data were collected from at least two eligible baseline cases (Baseline Phase, WGM not visible and resident unaware of its presence), the monitor was introduced and data collection continued for at least three more eligible cases (Visible Phase). Nine residents were initially enrolled, but due to scheduling difficulties only five residents completed the protocol. Data from cases using the WGM demonstrated a 50% decrease (3.58 +/- 1.34 l/min vs. 1.78 +/- 0.51 l/min (p = 0.009)) in the scavenger flow rates, which resulted in a 48% ($5.28 +/- 0.68 vs. $2.72 +/- 0.80 (p = 0.002)) decrease in hourly cost of wasted volatile anesthetic. There was no difference between the Baseline and Visible phases with regard to use of nitrous oxide or intravenous anesthetic agents. CONCLUSIONS. The WGM decreased wasted

  4. Investigation of chamber methods and a micrometeorological mass balance method for quantifying greenhouse gas emissions from animal manure

    NASA Astrophysics Data System (ADS)

    Park, Kyu-Hyun

    Various measurement methods to quantify greenhouse gas (GHG) emissions from manure storage or treatment facilities have been used. However, it is difficult to directly compare emission data measured with different methods, which causes uncertainties in national GHG inventories. In the micrometeorological mass balance (MMB) method, a gas flux consists of a horizontal mean flux (MF) and horizontal turbulent flux (TF) terms. In Chapter 2, methane (GH4 ) TF measurements obtained using a sonic anemometer and a tunable diode laser trace gas analyzer are presented. Contrary to previous studies in wind tunnels and flat-level field conditions, an overestimation of only 0.5% was observed by only considering the MF term. This means the MMB method without consideration of TF is suitable in complex field conditions with uneven topography, and farm buildings. In Chapter 3, the MMB method was compared to a floating chamber method. Of these, the floating chamber method has been extensively used for CH4 flux quantification. The MMB method, although providing advantages such as spatial integration of fluxes, requires fast response trace gas analyzers which are not widely available. The mean ratio of CH4 flux measured with the floating chamber method to that measured using the MMB method was 1.25, ranging from 1.07 to 1.83. Flux overestimation by the floating chamber could have been caused by location of the chamber and potential disturbances by the chamber. Frequent changes of the chamber location, use of several chambers, and/or avoiding chamber placement on 'hot spots' are recommended to decrease flux overestimation. In Chapter 4, CH4 fluxes measured with a mega chamber and eight small chambers during the in-vessel composting phase showed similar temporal variation, while nitrous oxide (N2O) fluxes were, significantly lower for the small chambers. The ratios of CH4 fluxes measured with a mega chamber to eight small chambers during the in-vessel composting phase were 0.72 and 1

  5. 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

  6. 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

  7. Measurements of soil permeability and pressure fields in EPA's soil-gas chamber. Report for May-August 1993

    SciTech Connect

    Mosley, R.B.; Snoddy, R.; Brubaker, S.A.

    1993-01-01

    The paper discusses the measurement of soil permeability and pressure fields using EPA's soil-gas chamber, designed to study the production and transport of radon and other potential indoor air pollutants originating in soils. The chamber is instrumented to measure distributions of radon and pressure fields and also moisture distributions and their resulting influence on soil permeability. An analytic solution for advective flow in the soil-gas chamber is presented which includes the effects of moisture-dependent spatial variations of the permeability. Measurements of the pressure field are compared with model calculations. Relatively good agreement between the measurements and calculations is obtained, except near the water level where boundary conditions are not rigorously satisfied.

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

    PubMed

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

    2015-05-07

    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.

  9. 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.

  10. 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.

  11. Implementation of Gas Sampling Chamber and Measuring Hardware for Capnograph System Considering Thermal Noise Effect and Time Response Characteristics

    DTIC Science & Technology

    2007-11-02

    chamber, thermal background effect I. INTRODUCTION As a measuring method for a capnograph system that determines indirectly the level of pCO2 in a...The chopping frequency of an IR lamp corresponds to the sampling frequency for the continuous measurement of the CO2 gas concentration without aliasing...order MFB(multiple feedback) lowpass filter. Finally, the use of 240×64 graphic LCD makes it easy to continuously observe and measure the CO2 gas

  12. A gas-tight Cu K alpha x-ray transparent reaction chamber for high-temperature x-ray diffraction analyses of halide gas/solid reactions.

    PubMed

    Shian, Samuel; Sandhage, Kenneth H

    2009-11-01

    An externally heated, x-ray transparent reaction chamber has been developed to enable the dynamic high temperature x-ray diffraction (HTXRD) analysis of a gas/solid [TiF(4)(g)/SiO(2)(s)] reaction involving a halide gas reactant formed at elevated temperatures (up to 350 degrees C) from a condensed source (TiF(4) powder) sealed within the chamber. The reaction chamber possessed x-ray transparent windows comprised of a thin (13 microm) internal layer of Al foil and a thicker (125 microm) external Kapton film. After sealing the SiO(2) specimens (diatom frustules or Stober spheres) above TiF(4) powder within the reaction chamber, the chamber was heated to a temperature in the range of 160-350 degrees C to allow for internal generation of TiF(4)(g). The TiF(4)(g) underwent a metathetic reaction with the SiO(2) specimen to yield a TiOF(2)(s) product. HTXRD analysis, using Cu K alpha x rays passed through the Kapton/Al windows of the chamber, was used to track the extent of SiO(2) consumption and/or TiOF(2) formation with time. The Al foil inner layer of the windows protected the Kapton film from chemical attack by TiF(4)(g), whereas the thicker, more transparent Kapton film provided the mechanical strength needed to contain this gas. By selecting an appropriate combination of x-ray transparent materials to endow such composite windows with the required thermal, chemical, and mechanical performance, this inexpensive reaction chamber design may be applied to the HTXRD analyses of a variety of gas/solid reactions.

  13. 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.

  14. Soil CO2 efflux measurement network by means of closed static chambers to monitor volcanic activity at Tenerife, Canary Islands

    NASA Astrophysics Data System (ADS)

    Amonte, Cecilia; García-Merino, Marta; Asensio-Ramos, María; Melián, Gladys; García-Hernández, Rubén; Pérez, Aaron; Hernández, Pedro A.; Pérez, Nemesio M.

    2017-04-01

    Tenerife (2304 km2) is the largest of the Canary Islands and has developed a central volcanic complex (Cañadas edifice), that started to grow about 3.5 My ago. Coeval with the construction of the Cañadas edifice, shield basaltic volcanism continued until the present along three rift zones oriented NW-SE, NE-SW and NS (hereinafter referred as NW, NE and NS respectively). Main volcanic historical activity has occurred along de NW and NE rift-zones, although summit cone of Teide volcano, in central volcanic complex, is the only area of the island where surface geothermal manifestations are visible. Uprising of deep-seated gases occurs along the aforementioned volcanic structures causing diffuse emissions at the surface environment of the rift-zones. In the last 20 years, there has been considerable interest in the study of diffuse degassing as a powerful tool in volcano monitoring programs. Diffuse degassing studies are even more important volcanic surveillance tool at those volcanic areas where visible manifestations of volcanic gases are absent. Historically, soil gas and diffuse degassing surveys in volcanic environments have focused mainly on CO2 because it is, after water vapor, the most abundant gas dissolved in magma. One of the most popular methods used to determine CO2 fluxes in soil sciences is based on the absorption of CO2 through an alkaline medium, in its solid or liquid form, followed by gravimetric, conductivity, or titration analyses. In the summer of 2016, a network of 31 closed static chambers was installed, covering the three main structural zones of Tenerife (NE, NW and NS) as well as Cañadas Caldera with volcanic surveillance porpoises. 50 cc of 0.1N KOH solution is placed inside the chamber to absorb the CO2 released from the soil. The solution is replaced weekly and the trapped CO2 is then analyzed at the laboratory by titration. The are expressed as weekly integrated CO2 efflux values. The CO2 efflux values ranged from 3.2 to 12.9 gṡm-2

  15. 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.

  16. 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.

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

    NASA Astrophysics Data System (ADS)

    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.

  18. 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.

  19. Integrated sUAS Greenhouse Gas Measurements and Imagery for Land Use Emissions Monitoring

    NASA Astrophysics Data System (ADS)

    Barbieri, L.; Wyngaard, J.; Galford, G. L.; Adair, C.

    2016-12-01

    Agriculture, Forestry and Other Land Uses (AFOLU) constitute the second largest anthropogenic source of greenhouse gas (GHG) emissions globally. Agriculture is the dominant source of emissions within that sector. There are a variety of agricultural land management strategies that can be implemented to reduce GHG emissions, but determining the best strategies is challenging. Emissions estimates are currently derived from GHG monitoring methods (e.g., static chambers, eddy flux towers) that are time and labor intensive, expensive, and use in-situ equipment. These methods lack the flexible, spatio-temporal monitoring necessary to reduce the high uncertainty in regional GHG emissions estimates. Small Unmanned Aerial Systems (sUAS) provide the rapid response data collection needed to monitor important field management events (e.g., manure spreading). Further, the ease of deployment of sUAS makes monitoring large regional extents over full-seasons more viable. To our knowledge, we present the first integration of sUAS remotely sensed imagery and GHG concentrations in agriculture and land use monitoring. We have developed and tested open-source hardware and software utilizing low-cost equipment (e.g., NDIR gas sensors and Canon cameras). Initial results show agreement with more traditional, proprietary equipment but at a fraction of the costs. Here we present data from test flights over agricultural areas under various management practices. The suite of data includes sUAS overpasses for imagery and CO2 concentration measurements, paired with field-based GHG measurements (static chambers). We have developed a set of best practices for sUAS data collection (e.g., time of day effects variability in localized atmospheric GHG concentrations) and discuss currently known challenges (e.g., accounting for external environmental factors such as wind speed). We present results on all sUAS GHG sampling methods paired with imagery and simultaneous static chamber monitoring for a

  20. Electret ion chamber-based passive radon-thoron discriminative monitors.

    PubMed

    Kotrappa, P; Steck, D

    2010-10-01

    Electret ion chambers (EICs), commercially available under brand name E-PERM(®), are widely used for measuring indoor and outdoor (222)Rn concentrations in air. These are designed to respond only to (222)Rn and not to (220)Rn by restricting diffusional entry area. Such radon EIC (R EIC) monitors are modified by increasing the entry area to allow (220)Rn, in addition to (222)Rn. Such modified units are called RT EIC. When a set of R and RT EICs are collocated, it is possible to discriminate and measure both radon and thoron concentrations, using appropriate calibration factors (CFs) and algorithms. The EICs come in different volumes, providing different sensitivities. The thoron CFs for 58-, 210- and 960-ml volume R and RT pairs are, respectively, 2.8-, 18.7- and 89-V drop per (kBq m(-3) d ), respectively. These provide much wider sensitivities and ranges compared to alpha track-based passive radon-thoron discriminative monitors.

  1. Preliminary results of Resistive Plate Chambers operated with eco-friendly gas mixtures for application in the CMS experiment

    NASA Astrophysics Data System (ADS)

    Abbrescia, M.; Van Auwegem, P.; Benussi, L.; Bianco, S.; Cauwenbergh, S.; Ferrini, M.; Muhammad, S.; Passamonti, L.; Pierluigi, D.; Piccolo, D.; Primavera, F.; Russo, A.; Saviano, G.; Tytgat, M.

    2016-09-01

    The operations of Resistive Plate Chambers in LHC experiments require Fluorine based (F-based) gases for optimal performance. Recent European regulations demand the use of environmentally unfriendly F-based gases to be limited or banned. In view of the CMS experiment upgrade, several tests are ongoing to measure the performance of the detector with these new ecological gas mixtures, in terms of efficiency, streamer probability, induced charge and time resolution. Prototype chambers with readout pads and with the standard CMS electronic setup are under test. In this paper preliminary results on performance of RPCs operated with a potential eco-friendly gas candidate 1,3,3,3-Tetrafluoropropene, commercially known as HFO-1234ze, with CO2 and CF3I based gas mixtures are presented and discussed for the possible application in the CMS experiment.

  2. A whole-plant chamber system for parallel gas exchange measurements of Arabidopsis and other herbaceous species.

    PubMed

    Kölling, Katharina; George, Gavin M; Künzli, Roland; Flütsch, Patrick; Zeeman, Samuel C

    2015-01-01

    Photosynthetic assimilation of carbon is a defining feature of the plant kingdom. The fixation of large amounts of carbon dioxide supports the synthesis of carbohydrates, which make up the bulk of plant biomass. Exact measurements of carbon assimilation rates are therefore crucial due to their impact on the plants metabolism, growth and reproductive success. Commercially available single-leaf cuvettes allow the detailed analysis of many photosynthetic parameters, including gas exchange, of a selected leaf area. However, these cuvettes can be difficult to use with small herbaceous plants such as Arabidopsis thaliana or plants having delicate or textured leaves. Furthermore, data from single leaves can be difficult to scale-up for a plant shoot with a complex architecture and tissues in different physiological states. Therefore, we constructed a versatile system-EGES-1-to simultaneously measure gas exchange in the whole shoots of multiple individual plants. Our system was designed to be able record data continuously over several days. The EGES-1 system yielded comparable measurements for eight plants for up to 6 days in stable, physiologically realistic conditions. The chambers seals have negligible permeability to carbon dioxide and the system is designed so as to detect any bulk-flow air leaks. We show that the system can be used to monitor plant responses to changing environmental conditions, such as changes in illumination or stress treatments, and to compare plants with phenotypically severe mutations. By incorporating interchangeable lids, the system could be used to measure photosynthetic gas exchange in several genera such as Arabidopsis, Nicotiana, Pisum, Lotus and Mesembryanthemum. EGES-1 can be introduced into a variety of growth facilities and measure gas exchange in the shoots diverse plant species grown in different growth media. It is ideal for comparing photosynthetic carbon assimilation of wild-type and mutant plants and/or plants undergoing

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

    SciTech Connect

    Barboza, Nigel Oswald

    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 ~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, ~200 g/cm3 and ~20 keV, that a substantial number of fusion reactions occur; the pellet microexplosion typically releases ~350 MJ of energy in optimized power plant scenarios.

  4. 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.

  5. 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.

  6. Field-scale gas tracing experiment in unsaturated fractured media: from deep injection to surface monitoring

    NASA Astrophysics Data System (ADS)

    Guillon, S.; Pili, E.; Sabroux, J.; Sestier-Carlin, R.; Adler, P. M.

    2011-12-01

    For CO2 sequestration as for other applications, it is important to understand transfer mechanisms of gases in unsaturated fractured rocks from experiment and to develop modeling capabilities. We carried out a field-scale tracing experiment using SF6 with the aim to serve for a forthcoming experiment using CO2. The experimental site was well characterized (mineralogy and fracturation). Transport parameters were estimated from the field, especially permeability and dilution factor. We also evaluated methods to monitor tracer breakthrough at the surface. At the Roselend Natural Laboratory (French Alps), a tunnel provides access to the heart of unsaturated fractured crystalline rocks, at 55 m depth below ground surface. This underground research facility allows studying gas exchange between a 60 m3 chamber isolated at the dead-end of the tunnel and the surface. At the topographic surface, ten 10 meter-long vertical boreholes and one 60 meter-long subhorizontal borehole were used to monitor tracer breakthrough. Stereological analysis of fractures in the tunnel previously led to permeability estimation. Similar analysis of drilled cores (density and orientation of fractures) gave additional permeability estimates in the subsurface. Gas permeability was also determined from pneumatic injection tests in both the injection chamber and subsurface boreholes. Steady-state and transient experiments were analyzed by modeling in real geometry. Long-term continuous pressure monitoring in the isolated chamber and the packed-off boreholes were also used for permeability estimation. We found equivalent air permeability of the order of 10-12 m2 which compares well with previous estimations. Following baseline determination, SF6 was injected at 1000 ppmV in the isolated chamber that was then pressurized to 150 mbar above atmospheric pressure during 2 hours. During all the experiment SF6 concentration was continuously monitored inside the isolated chamber and in front of the isolation

  7. Production of sugarcane bagasse-based activated carbon for formaldehyde gas removal from potted plants exposure chamber.

    PubMed

    Mohamed, Elham F; El-Hashemy, Mohammed A; Abdel-Latif, Nasser M; Shetaya, Waleed H

    2015-12-01

    Agricultural wastes such as rice straw, sugar beet, and sugarcane bagasse have become a critical environmental issue due to growing agriculture demand. This study aimed to investigate the valorization possibility of sugarcane bagasse waste for activated carbon preparation. It also aimed to fully characterize the prepared activated carbon (BET surface area) via scanning electron microscope (SEM) and in terms of surface functional groups to give a basic understanding of its structure and to study the adsorption capacity of the sugarcane bagasse-based activated carbon using aqueous methylene blue (MB). The second main objective was to evaluate the performance of sugarcane bagasse-based activated carbon for indoor volatile organic compounds removal using the formaldehyde gas (HCHO) as reference model in two potted plants chambers. The first chamber was labeled the polluted chamber (containing formaldehyde gas without activated carbon) and the second was taken as the treated chamber (containing formaldehyde gas with activated carbon). The results indicated that the sugarcane bagasse-based activated carbon has a moderate BET surface area (557 m2/g) with total mesoporous volume and microporous volume of 0.310 and 0.273 cm3/g, respectively. The prepared activated carbon had remarkable adsorption capacity for MB. Formaldehyde removal rate was then found to be more than 67% in the treated chamber with the sugarcane bagasse-based activated carbon. The plants' responses for this application as dry weight, chlorophyll contents, and protein concentration were also investigated. Preparation of activated carbon from sugarcane bagasse (SCBAC) is a promising approach to produce cheap and efficient adsorbent for gas pollutants removal. It may be also a solution for the agricultural wastes problems in big cities, particularly in Egypt. MB adsorption tests suggest that the SCBAC have high adsorption capacity. Formaldehyde gas removal in the plant chambers indicates that the SCBAC have

  8. Gas chromatography vs. quantum cascade laser-based N2O flux measurements using a novel chamber design

    NASA Astrophysics Data System (ADS)

    Brümmer, Christian; Lyshede, Bjarne; Lempio, Dirk; Delorme, Jean-Pierre; Rüffer, Jeremy J.; Fuß, Roland; Moffat, Antje M.; Hurkuck, Miriam; Ibrom, Andreas; Ambus, Per; Flessa, Heinz; Kutsch, Werner L.

    2017-03-01

    Recent advances in laser spectrometry offer new opportunities to investigate the soil-atmosphere exchange of nitrous oxide. During two field campaigns conducted at a grassland site and a willow field, we tested the performance of a quantum cascade laser (QCL) connected to a newly developed automated chamber system against a conventional gas chromatography (GC) approach using the same chambers plus an automated gas sampling unit with septum capped vials and subsequent laboratory GC analysis. Through its high precision and time resolution, data of the QCL system were used for quantifying the commonly observed nonlinearity in concentration changes during chamber deployment, making the calculation of exchange fluxes more accurate by the application of exponential models. As expected, the curvature values in the concentration increase was higher during long (60 min) chamber closure times and under high-flux conditions (FN2O > 150 µg N m-2 h-1) than those values that were found when chambers were closed for only 10 min and/or when fluxes were in a typical range of 2 to 50 µg N m-2 h-1. Extremely low standard errors of fluxes, i.e., from ˜ 0.2 to 1.7 % of the flux value, were observed regardless of linear or exponential flux calculation when using QCL data. Thus, we recommend reducing chamber closure times to a maximum of 10 min when a fast-response analyzer is available and this type of chamber system is used to keep soil disturbance low and conditions around the chamber plot as natural as possible. Further, applying linear regression to a 3 min data window with rejecting the first 2 min after closure and a sampling time of every 5 s proved to be sufficient for robust flux determination while ensuring that standard errors of N2O fluxes were still on a relatively low level. Despite low signal-to-noise ratios, GC was still found to be a useful method to determine the mean the soil-atmosphere exchange of N2O on longer timescales during specific campaigns. Intriguingly

  9. Radon exhalation rates from building materials using electret ion chamber radon monitors in accumulators.

    PubMed

    Kotrappa, Payasada; Stieff, Frederick

    2009-08-01

    An electret ion chamber (EIC) radon monitor in a sealed accumulator measures the integrated average radon concentration at the end of the accumulation duration. Theoretical equations have been derived to relate such radon concentrations (Bq m(-3) ) to the radon emanation rate (Bq d(-1)) from building materials enclosed in the accumulator. As an illustration, a 4-L sealable glass jar has been used as an accumulator to calculate the radon emanation rate from different granite samples. The radon emanation rate was converted into radon flux (Bq mm(-2) d(-1)) by dividing the emanation rate by surface area of the sample. Fluxes measured on typical, commercially available granites ranged from 20-30 Bq m(-2) d(-1). These results are similar to the results reported in the literature. The lower limit of detection for a 2-d measurement works out to be 7 Bq m(-2) d(-1). Equations derived can also be used for other sealable accumulators and other integrating detectors, such as alpha track detectors.

  10. Preliminary results with a strip ionization chamber used as beam monitor for hadrontherapy treatments

    NASA Astrophysics Data System (ADS)

    Boriano, A.; Bourhaleb, F.; Cirio, R.; Cirrone, G. A. P.; Cuttone, G.; Donetti, M.; Garelli, E.; Giordanengo, S.; Luparia, A.; Marchette, F.; Peroni, C.; Raffaele, L.; Sabini, M. G.; Valastro, L.

    2006-01-01

    Preliminary results are presented from a test of a parallel plate ionization chamber with the anode segmented in strips (MOPI) to be used as a beam monitor for therapeutical treatments on the 62 MeV proton beam line of the INFN-LNS Superconducting Cyclotron. Ocular pathologies have been treated at the Catana facility since March 2002. The detector, placed downstream of the patient collimator, will allow the measurement of the relevant beam diagnostic parameters during treatment such as integrated beam fluence, for dose determination; the beam baricentre, width and asymmetry will be obtained from the fluence profile sampled with a resolution of about 100 Urn at a rate up to 1 kHz with no dead time. In this test, carried out at LNS, the detector has been exposed to different beam shapes and the integrated fluence derived by the measured beam profiles has been compared with that obtained with other dosimeters normally used for treatment. The skewness of the beam profile has been measured and shown to be suitable to on-line check variations of the beam shape.

  11. 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

  12. 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.

  13. 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.

  14. 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.

  15. 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.

  16. Backscatter towards the monitor ion chamber in high-energy photon and electron beams: charge integration versus Monte Carlo simulation.

    PubMed

    Verhaegen, F; Symonds-Tayler, R; Liu, H H; Nahum, A E

    2000-11-01

    In some linear accelerators, the charge collected by the monitor ion chamber is partly caused by backscattered particles from accelerator components downstream from the chamber. This influences the output of the accelerator and also has to be taken into account when output factors are derived from Monte Carlo simulations. In this work, the contribution of backscattered particles to the monitor ion chamber response of a Varian 2100C linac was determined for photon beams (6, 10 MV) and for electron beams (6, 12, 20 MeV). The experimental procedure consisted of charge integration from the target in a photon beam or from the monitor ion chamber in electron beams. The Monte Carlo code EGS4/BEAM was used to study the contribution of backscattered particles to the dose deposited in the monitor ion chamber. Both measurements and simulations showed a linear increase in backscatter fraction with decreasing field size for photon and electron beams. For 6 MV and 10 MV photon beams, a 2-3% increase in backscatter was obtained for a 0.5 x 0.5 cm2 field compared to a 40 x 40 cm2 field. The results for the 6 MV beam were slightly higher than for the 10 MV beam. For electron beams (6, 12, 20 MeV), an increase of similar magnitude was obtained from measurements and simulations for 6 MeV electrons. For higher energy electron beams a smaller increase in backscatter fraction was found. The problem is of less importance for electron beams since large variations of field size for a single electron energy usually do not occur.

  17. 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

  18. Low-pressure micro-strip gas chamber and a search for a high-efficiency secondary-electron emitter

    SciTech Connect

    Anderson, D.F.; Kwan, S.; Sbarra, C.

    1994-11-01

    The test beam performance of a low-pressure micro-strip gas chamber with a thick CsI secondary-electron emitting surface as the source of primary ionization is presented. A study of the secondary-electron yield of CsI and KCl coated surfaces are discussed, as well as a promising new technique, CsI-treated CVD diamond films.

  19. 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.

  20. 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.

  1. [Opacification of an intraocular lens: calcification of hydrophilic intraocular lenses after gas tamponade of the anterior chamber].

    PubMed

    Schmidinger, G; Pemp, B; Werner, L

    2013-11-01

    A patient with endothelial dystrophy was treated with Descemet stripping automated endothelial keratoplasty (DSAEK) combined with cataract extraction and implantation of a hydrophilic intraocular lens (IOL, Lentis-L312, Oculentis) but visual acuity dropped from 0.15 logMAR to 0.52 logMAR 18 months later due to calcification of the IOL. With new methods of lamellar corneal transplantation being used more frequently the number of necessary anterior chamber tamponades with air/gas are increasing. In cataract cases in which a gas tamponade and transplantation might be necessary later on (cornea guttata), hydrophilic IOLs should be avoided.

  2. 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.

  3. 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.

  4. Continuous soil VOCl measurements with automated flux chambers and micro-ECD gas chromatography coupled with the thermal desorption and cooled injection systems

    NASA Astrophysics Data System (ADS)

    Molodovskaya, M. S.; Svensson, T.; Pitts, A.; Delmonte, J.; Nesic, Z.; Oberg, G.

    2010-12-01

    The volatile organic chlorinated compounds (VOCl) are important components of the global chlorine budget. The origin of VOCl in the environment was for decades thought to be strictly anthropogenic. Over the past decade, a number of studies have however shown that VOCls are naturally formed in soil, and nowadays this source is recognized as a crucial part of the global biogeochemical chlorine cycle. The relative contribution of soil VOCl to the global chlorine cycle is however unclear, a key reason being that monitoring of soil VOCl is complicated by low concentrations and high variability of emission rates. Static chamber deployments coupled with canister gas sampling and gas chromatography (GC) analysis is the most commonly used method for quantifying VOCl emissions. Static chambers are however of limited use for estimating larger scale fluxes since the method is highly labor intensive (leading low sampling frequency). The poor data resolution resulting from these limitations can strongly bias the data extrapolation. Here, we report a method that would allow more continuous and precise VOCl flux measurements. The study has been carried out in a forest in British Columbia, Canada, using automated dynamic chambers and advanced GC technique. The chamber setup is based on a design that previously has been employed and proven successful for carbon dioxide and soil respiration measurements. The method includes a collar permanently inserted into the ground and an attached dome-shaped cover. The air from the closed chamber is pumped through the on-site sampling device. The cover opens and closes automatically between deployments (40 min in average), which helps to minimize the chamber supervision and obtain more continuous data. Soil VOCl concentrations are commonly at the ppt-level, much lower than atmospheric carbon dioxide, so necessary adjustments were made to the chamber system to pre-concentrate the compounds of interest. During each deployment, soil air from the

  5. Chamber measurement of surface-atmosphere trace gas exchange--Numerical evaluation of dependence on soil interfacial layer, and source/sink products

    USGS Publications Warehouse

    Hutchinson, G.L.; Livingston, G.P.; Healy, R.W.; Striegl, R.G.

    2000-01-01

    We employed a three-dimensional finite difference gas diffusion model to simulate the performance of chambers used to measure surface-atmosphere tace gas exchange. We found that systematic errors often result from conventional chamber design and deployment protocols, as well as key assumptions behind the estimation of trace gas exchange rates from observed concentration data. Specifically, our simulationshowed that (1) when a chamber significantly alters atmospheric mixing processes operating near the soil surface, it also nearly instantaneously enhances or suppresses the postdeployment gas exchange rate, (2) any change resulting in greater soil gas diffusivity, or greater partitioning of the diffusing gas to solid or liquid soil fractions, increases the potential for chamber-induced measurement error, and (3) all such errors are independent of the magnitude, kinetics, and/or distribution of trace gas sources, but greater for trace gas sinks with the same initial absolute flux. Finally, and most importantly, we found that our results apply to steady state as well as non-steady-state chambers, because the slow rate of gas diffusion in soil inhibits recovery of the former from their initial non-steady-state condition. Over a range of representative conditions, the error in steady state chamber estimates of the trace gas flux varied from -30 to +32%, while estimates computed by linear regression from non-steadystate chamber concentrations were 2 to 31% too small. Although such errors are relatively small in comparison to the temporal and spatial variability characteristic of trace gas exchange, they bias the summary statistics for each experiment as well as larger scale trace gas flux estimates based on them.

  6. Determination of acidic gas and particle concentrations in open-top field chambers. Final report

    SciTech Connect

    Bytnerowicz, A.

    1993-06-01

    The report describes determinations of concentrations of gaseous and particulate air pollutants in open-top field chambers used for exposing of tree seedlings to acidic rain and ozone. During the study, air pollution concentrations were measured in the following types of chambers: charcoal-filtered (control); ambient air with ambient ozone concentrations; ambient air with double ambient ozone concentrations. Concentrations of gaseous nitric acid, gaseous nitrous acid, ammonia, sulfur dioxide and nitrate, ammonium and sulfate in fine and coarse particulate fractions were determined. Increased concentrations of nitric acid were detected in chambers due to the generation of ozone, however, these concentrations were lower than the ambient concentrations measured in outside plots. Elevated concentrations of nitrous acid were detected in the charcoal-filtered chambers.

  7. 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).

  8. 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.

  9. The most recent international intercomparisons of radon and thoron monitors with the NIRS radon and thoron chambers.

    PubMed

    Janik, M; Yonehara, H

    2015-06-01

    The fifth international intercomparison for radon and fourth for thoron monitors were conducted at National Institute of Radiological Sciences (Japan) with the radon and thoron chambers. The tests were made under two different exposures to radon and two exposures (in two rounds due to limited space in the thoron chamber) to thoron. In these most recent intercomparisons, two new graphical methods recommended by the ISO standard, Mandel's h statistic and the Youden plot, were implemented to evaluate the consistency between laboratories and within laboratories.The presented data indicated that the performance quality of laboratories for radon measurement as expressed by the percentage difference parameter has been stable since the first international intercomparison for passive monitors carried out in 2007, and it amounted to around 50 for 10 % of the difference from the reference value. The thoron exercise showed that further development and additional studies to improve its measuring methods and reliability are needed.

  10. 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.

  11. Hydrocarbon sensor for exhaust gas monitoring

    SciTech Connect

    Pham, A Q; Visser, J H; Ejakov, S; Glass, R S

    2000-08-28

    Due to increasing environmental concerns, in 1994, the California Air Resources Board (CARB) and the U.S. Environmental Protection Agency (EPA) began implementing regulations that require automakers to incorporate comprehensive on-board diagnostics into new vehicles. The purpose is to monitor emissions, which will allow early detection of any malfunctioning of the engine and/or exhaust treatment system. Currently, monitorings of hydrocarbon and NOx emissions are regarded as being the most critical for evaluating car emissions.

  12. 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.

  13. High-rangeability ultrasonic gas flowmeter for monitoring flare gas.

    PubMed

    Mylvaganam, K S

    1989-01-01

    A transit-time ultrasonic gas flowmeter for high-rangeability requirements, such as those encountered in flare-gas flow-metering, is presented. The concept of ray rescue angle for the orientation of the ultrasonic transducers in single-beam transit-time ultrasonic flowmeters is introduced to overcome the problem of ultrasonic beam drift in high-velocity flows. To overcome problems associated with noise at high velocities, a chirp signal is used. To preserve the accuracy of the meter at low velocities near zero flow, a combination of chirp and continuous-wave signals is used to interrogate the flow. Overall system performance is presented, based on results from extensive wind-tunnel tests.

  14. On line high dose static position monitoring by ionization chamber detector for industrial gamma irradiators.

    PubMed

    Rodrigues, Ary A; Vieira, Jose M; Hamada, Margarida M

    2010-01-01

    A 1 cm(3) cylindrical ionization chamber was developed to measure high doses on line during the sample irradiation in static position, in a (60)Co industrial plant. The developed ionization chamber showed to be suitable for use as a dosimeter on line. A good linearity of the detector was found between the dose and the accumulated charge, independently of the different dose rates caused by absorbing materials.

  15. Constraining Gas Diffusivity-Soil Water Content Relationships in Forest Soils Using Surface Chamber Fluxes and Depth Profiles of Multiple Trace Gases

    NASA Astrophysics Data System (ADS)

    Dore, J. E.; Kaiser, K.; Seybold, E. C.; McGlynn, B. L.

    2012-12-01

    Forest soils are sources of carbon dioxide (CO2) to the atmosphere and can act as either sources or sinks of methane (CH4) and nitrous oxide (N2O), depending on redox conditions and other factors. Soil moisture is an important control on microbial activity, redox conditions and gas diffusivity. Direct chamber measurements of soil-air CO2 fluxes are facilitated by the availability of sensitive, portable infrared sensors; however, corresponding CH4 and N2O fluxes typically require the collection of time-course physical samples from the chamber with subsequent analyses by gas chromatography (GC). Vertical profiles of soil gas concentrations may also be used to derive CH4 and N2O fluxes by the gradient method; this method requires much less time and many fewer GC samples than the direct chamber method, but requires that effective soil gas diffusivities are known. In practice, soil gas diffusivity is often difficult to accurately estimate using a modeling approach. In our study, we apply both the chamber and gradient methods to estimate soil trace gas fluxes across a complex Rocky Mountain forested watershed in central Montana. We combine chamber flux measurements of CO2 (by infrared sensor) and CH4 and N2O (by GC) with co-located soil gas profiles to determine effective diffusivity in soil for each gas simultaneously, over-determining the diffusion equations and providing constraints on both the chamber and gradient methodologies. We then relate these soil gas diffusivities to soil type and volumetric water content in an effort to arrive at empirical parameterizations that may be used to estimate gas diffusivities across the watershed, thereby facilitating more accurate, frequent and widespread gradient-based measurements of trace gas fluxes across our study system. Our empirical approach to constraining soil gas diffusivity is well suited for trace gas flux studies over complex landscapes in general.

  16. Photometric calibration of an in situ broadband optical thickness monitoring of thin films in a large vacuum chamber.

    PubMed

    Hofman, David; Sassolas, Benoit; Michel, Christophe; Balzarini, Laurent; Pinard, Laurent; Teillon, Julien; David, Bertrand; Lagrange, Bernard; Barthelemy-Mazot, Eleonore; Cagnoli, Gianpietro

    2017-01-20

    To improve the in situ monitoring of thin films at the Laboratoire des Matériaux Avancés, a broadband optical monitoring of the coated thin films was developed and installed in the biggest ion-beam sputtering machine in the world. Due to the configuration of the coating machine and the chamber strain under vacuum, a standard calibration procedure is impossible and a double-beam optical system is not suitable. A novel theoretical and practical solution to calibrate the measurements was found and is described in this paper. Some relevant results achieved thanks to this technique are discussed as well.

  17. 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.

  18. 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.

  19. 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.

  20. Monitoring of Gas Emboli During Hysteroscopic Surgery: A Prospective Study.

    PubMed

    Liu, Sheng-Qun; Zhao, Su-Zhen; Li, Zhan-Wen; Lv, Su-Ping; Liu, Yue-Qiang; Li, Yi

    2017-04-01

    Previous studies have demonstrated a high frequency of gas emboli during hysteroscopy, but guidelines for the prevention, early detection, and intervention of gas embolism during hysteroscopic procedures are still lacking. This study aimed to gain a clearer understanding of risk factors and specific signs and symptoms associated with gas emboli. This prospective study enrolled 120 women scheduled for hysteroscopy using 5% glucose as distension medium. The gas bubbles were monitored sequentially in internal iliac vein, common iliac vein, inferior vena cava, superior vena cava, heart, and pulmonary artery under the gray-scale imaging of Doppler ultrasound. The frequency, extent, and the hemodynamic and respiratory effects of gas emboli were evaluated. The interventions and outcomes were recorded. The risk factors associated with gas emboli, and their relationship with the frequency and extent of gas emboli, were assessed. In our study, evidence of gas emboli under Doppler ultrasound monitoring was observed in 44 (36.7%) patients. The operation was continued and finished as soon as possible for patients presenting with stable vital signs or transient hemodynamic and respiratory changes, which resolved spontaneously without intervention. The operation was paused for patients presenting with significant hemodynamic changes or loss of consciousness, and the operation was resumed shortly after resumption of stable vital signs following symptomatic treatment. All patients in our study finished the operation and recovered without developing serious complications. Data analysis showed prolonged procedure duration and increased bleeding volume were both positively correlated with the frequency and extent of gas emboli. Our study demonstrated a high frequency of gas emboli during hysteroscopy. Doppler ultrasonic monitoring combined with a clearer understanding of specific signs, symptoms, and risk factors will facilitate early detection and intervention of gas emboli during

  1. Gas-particle partitioning of semivolatile organic compounds (SOCs) on mixtures of aerosols in a smog chamber.

    PubMed

    Chandramouli, Bharadwaj; Jang, Myoseon; Kamens, Richard M

    2003-09-15

    The partitioning behavior of a set of diverse SOCs on two and three component mixtures of aerosols from different sources was studied using smog chamber experimental data. A set of SOCs of different compound types was introduced into a system containing a mixture of aerosols from two or more sources. Gas and particle samples were taken using a filter-filter-denuder sampling system, and a partitioning coefficient Kp was estimated using Kp = Cp/(CgTSP). Particle size distributions were measured using a differential mobility analyzer and a light scattering detector. Gas and particle samples were analyzed using GCMS. The aerosol composition in the chamber was tracked chemically using a combination of signature compounds and the organic matter mass fraction (f(om)) of the individual aerosol sources. The physical nature of the aerosol mixture in the chamber was determined using particle size distributions, and an aggregate Kp was estimated from theoretically calculated Kp on the individual sources. Model fits for Kp showed that when the mixture involved primary sources of aerosol, the aggregate Kp of the mixture could be successfully modeled as an external mixture of the Kp on the individual aerosols. There were significant differences observed for some SOCs between modeling the system as an external and as an internal mixture. However, when one of the aerosol sources was secondary, the aggregate model Kp required incorporation of the secondary aerosol products on the preexisting aerosol for adequate model fits. Modeling such a system as an external mixture grossly overpredicted the Kp of alkanes in the mixture. Indirect evidence of heterogeneous, acid-catalyzed reactions in the particle phase was also seen, leading to a significant increase in the polarity of the resulting aerosol mix and a resulting decrease in the observed Kp of alkanes in the chamber. The model was partly consistent with this decrease but could not completely explain the reduction in Kp because of

  2. 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.

  3. 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.

  4. A ZigBee-based wireless system for monitoring vital signs in hyperbaric chambers: Technical report.

    PubMed

    Carmona, Cristian; Alorda, Bartomeu; Gracia, Luis; Perez-Vidal, Carlos; Salinas, Antonio

    2017-01-01

    This paper presents the replacement of a traditional wired communication link of the hyperbaric chambers with a wireless ZigBee-based system. This move allows a reduction in the costs of seals capable of withstanding the internal pressures and gives rise to a more versatile system. The new system is able to capture and process individual vital signs like the electrocardiography signal, and other analog sources, sending the data to an external computer and allowing analysis, representation and sharing with medical staff. This system solves such problems as the attenuation of the signal produced by the metal walls of the hyperbaric chamber and has a coverage area large enough to manage up to six patients with an effective data rate conversion of 2kHz. Furthermore, a battery-based and multiparameter platform is designed for multipatient hyperbaric chambers. Copyright© Undersea and Hyperbaric Medical Society.

  5. 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.

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

    USDA-ARS?s Scientific Manuscript database

    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. 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.

  8. Performance of the Gas Gain Monitoring system of the CMS RPC muon detector and effective working point fine tuning

    NASA Astrophysics Data System (ADS)

    Colafranceschi, S.; Benussi, L.; Bianco, S.; Passamonti, L.; Piccolo, D.; Pierluigi, D.; Russo, A.; Saviano, G.; Vendittozzi, C.; Abbrescia, M.; Aleksandrov, A.; Berzano, U.; Calabria, C.; Carrillo, C.; Colaleo, A.; Genchev, V.; Iaydjiev, P.; Kang, M.; Lee, K. S.; Loddo, F.; Park, S. K.; Pugliese, G.; Maggi, M.; Shin, S.; Rodozov, M.; Shopova, M.; Sultanov, G.; Verwilligen, P.

    2012-12-01

    The Gas Gain Monitoring (GGM) system of the Resistive Plate Chamber (RPC) muon detector in the Compact Muon Solenoid (CMS) experiment provides fast and accurate determination of the stability in the working point conditions due to gas mixture changes in the closed loop recirculation system. In 2011 the GGM began to operate using a feedback algorithm to control the applied voltage, in order to keep the GGM response insensitive to environmental temperature and atmospheric pressure variations. Recent results are presented on the feedback method used and on alternative algorithms.

  9. 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.

  10. NSPS monitoring options for landfill gas

    SciTech Connect

    Stollings, W.A.

    1998-12-31

    The analytical methods prescribed in the New Source Performance Standards (NSPS) for Municipal Solid Waste (MSW) landfills are USEPA Method 18 and USEPA Method 25-C/3-C. There have been considerable confusion and problems in the implementation of monitoring programs using these methods. The requirements for these methods are reviewed and compared. Many of the positive and negative aspects for each of these methods are detailed and possible options are examined. Results of several field samples comparing Non-Methane Organic Compounds (NMOC) to a modified TO-14 and TO-15 analysis are reviewed. Results of an inter-laboratory analyses of USEPA audits and field samples are also compared. The modifications to the methods and their effects upon the reported results are explored. This information will be useful in planning and implementing defendable sampling programs for NSPS

  11. [Point-of-Care-Monitoring: Blood gas analysis].

    PubMed

    Bickenbach, Johannes; Marx, Gernot

    2010-11-01

    Electrolyte- and acid-base-balance are relevant determinants for metabolic processes whose real time analysis is obligatory particularly in perioperative and intensive care treated patients. Also, the oxygenation status of the blood as a determinant for the oxygen supply of an organism and for the gas exchange is measured. By use of "point-of-care" (POC) monitoring, these important variables of blood gas analysis (BGA) can be measured real-time, potential mechanisms of compensation identified and disorder of homoeostasis reconstituted quickly. This article deals with the presentation of relevant parameters of blood gas analysis, potential pathologies and their treatment. © Georg Thieme Verlag Stuttgart · New York.

  12. 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.

  13. Combination of two Gas Electron Multipliers and a Micromegas as gain elements for a time projection chamber

    NASA Astrophysics Data System (ADS)

    Aiola, S.; Ehlers, R. J.; Gu, S.; Harris, J. W.; Majka, R.; Mulligan, J. D.; Oliver, M.; Schambach, J.; Smirnov, N.

    2016-10-01

    We measured the properties of a novel combination of two Gas Electron Multipliers with a Micromegas for use as amplification devices in high-rate gaseous time projection chambers. The goal of this design is to minimize the buildup of space charge in the drift volume of such detectors in order to eliminate the standard gating grid and its resultant dead time, while preserving good tracking and particle identification performance. To characterize this micro-pattern gas detector configuration, we measured the positive ion back-flow and energy resolution at various element gains and electric fields, using a variety of gases, and additionally studied crosstalk effects and discharge rates. At a gain of 2000, this configuration achieves an ion back-flow below 0.4% and an energy resolution better than σ / E = 12 % for 55Fe X-rays.

  14. Portable Hyperbaric Chamber

    NASA Technical Reports Server (NTRS)

    Schneider, William C. (Inventor); Locke, James P. (Inventor); DeLaFuente, Horacio (Inventor)

    2001-01-01

    A portable, collapsible hyperbaric chamber was developed. A toroidal inflatable skeleton provides initial structural support for the chamber, allowing the attendant and/or patient to enter the chamber. Oval hatches mate against bulkhead rings, and the hyperbaric chamber is pressurized. The hatches seal against an o-ring, and the internal pressure of the chamber provides the required pressure against the hatch to maintain an airtight seal. In the preferred embodiment, the hyperbaric chamber has an airlock to allow the attendant to enter and exit the patient chamber during treatment. Visual communication is provided through portholes in the patient and/or airlock chamber. Life monitoring and support systems are in communication with the interior of the hyperbaric chamber and/or airlock chamber through conduits and/or sealed feed-through connectors into the hyperbaric chamber.

  15. Portable Hyperbaric Chamber

    NASA Technical Reports Server (NTRS)

    Schneider, William C. (Inventor); Locke, James P. (Inventor); DeLaFuente, Horacio (Inventor)

    2001-01-01

    A portable, collapsible hyperbaric chamber was developed. A toroidal inflatable skeleton provides initial structural support for the chamber, allowing the attendant and/or patient to enter the chamber. Oval hatches mate against bulkhead rings, and the hyperbaric chamber is pressurized. The hatches seal against an o-ring, and the internal pressure of the chamber provides the required pressure against the hatch to maintain an airtight seal. In the preferred embodiment, the hyperbaric chamber has an airlock to allow the attendant to enter and exit the patient chamber during treatment. Visual communication is provided through portholes in the patient and/or airlock chamber. Life monitoring and support systems are in communication with the interior of the hyperbaric chamber and/or airlock chamber through conduits and/or sealed feed-through connectors into the hyperbaric chamber.

  16. 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.

  17. Gas dynamics and radiative heat transfer in IFE chambers with emphasis on the HYLIFE-II design

    NASA Astrophysics Data System (ADS)

    Jantzen, Caron Ann

    Gas dynamics in a heavy-ion inertial-fusion energy power plant have been modeled using the two-dimensional code, TSUNAMI. After fusion, approximately 2/3 of the yield energy will be given off as 14 Mev neutrons and the remaining third partitioned between target x-rays and debris energy. The chamber dynamic events which follow the fusion event occur over three distinct time periods, permitting separation of the underlying phenomena. Simulations of the HYLIFE-II reactor design were then run and results compared using both ideal-gas and partialionization equations of state. Results from a cylindrically symmetric simulation indicate that an initial, low density, burst of high-energy particles enters the final focus section of the heavy ion driver within 120mus of the blast and a second, larger, density rise occurs approximately 100mus later. Uncertainty in IFE target design motivated a parametric study of the x-ray to debris kinetic energy. Increasing this ratio lead to more jet ablation by target x-rays and, therefore, higher chamber densities. Chamber averaged temperature remained high, around 2.1 eV. Therefore, a subsequent study considered secondary radiation emitted by this hot vapor. The photon transport equation was applied in a finite difference model to both the target and ablation regions. Result indicated that radiation from the expanding target debris supplies 15MJ of energy to the liquid jets within the first 12mus of target ignition and becomes negligible beyond that time. In an inertial fusion energy (IFE) target chamber using thick-liquid protection, placing liquid surfaces close to the fusion target helps reduce pumping cost and final-focus stand-off distance. An additional issue then becomes the impulse load delivered to protective jets by target debris and x-ray ablated material since this pressure load provides the most important boundary condition for the subsequent liquid hydraulic response, pocket disruption, droplet generation, and pocket

  18. 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.

  19. Light-induced multiphase chemistry of gas phase ozone on aqueous pyruvic and oxalic acids: Aerosol chamber study

    NASA Astrophysics Data System (ADS)

    Gligorovski, S.; Grgic, I.; Net, S.; Böge, O.; Iinuma, Y.; Kahnt, A.; Scheinhardt, S.; Herrmann, H.; Wortham, H.

    2010-12-01

    The light-absorbing organic compounds present in and on condensed aerosol particles interacting with trace gases such as ozone can initiate a new and potentially important photo-induced multiphase chemistry. However, investigations of light induced multiphase processes are very scarce at present. We have launched the idea of pyruvic acid (PA) acting as a photosensitizer in the multiphase reactions between gas-phase ozone and aqueous oxalic acid (OA). The performed photochemical batch experiments yielded a complex suite of organic molecules which resulted primarily from the oligomerization of OA/PA and subsequent reactions, including decarboxylation and cycloadition (Grgic et al., 2010). In the atmosphere, pyruvic acid will always be accompanied by other carboxylic acids (and also other organics) which are constituents of either aerosol particles or aqueous droplets the effects of a possible photochemistry triggered by pyruvic acid should be experimentally studied in depth and under natural conditions as far as possible. Hence, in a very recent study experiments in the aerosol chamber facility LEAK at IFT, Leipzig, were performed to verify the influence of pyruvic on the multiphase (photo)oxidation of oxalic acid. The aim of these experiments was to study the multiphase photo-induced oxidation reactions with airborne deliquescent particles to demonstrate the applicability of the reactions mentioned above under more realistic conditions than in a batch reactor. State of the art sampling and analytical tools were applied for the analysis of the ongoing chamber runs and the formed particulate products which include denuder sampling, carbonyl compound derivatisation, PTR-MS measurements, GC-MS measurements and HPLC-MS and CE-MS for the particle phase. First results from these joint complex chamber experiments will be presented and discussed. Reference: Grgić I., Nieto-Gligorovski L.I., Net S., Temime-Roussel B., Gligorovski S., Wortham H. Light induced multiphase

  20. A combined segmented anode gas ionization chamber and time-of-flight detector for heavy ion elastic recoil detection analysis

    NASA Astrophysics Data System (ADS)

    Ström, Petter; Petersson, Per; Rubel, Marek; Possnert, Göran

    2016-10-01

    A dedicated detector system for heavy ion elastic recoil detection analysis at the Tandem Laboratory of Uppsala University is presented. Benefits of combining a time-of-flight measurement with a segmented anode gas ionization chamber are demonstrated. The capability of ion species identification is improved with the present system, compared to that obtained when using a single solid state silicon detector for the full ion energy signal. The system enables separation of light elements, up to Neon, based on atomic number while signals from heavy elements such as molybdenum and tungsten are separated based on mass, to a sample depth on the order of 1 μm. The performance of the system is discussed and a selection of material analysis applications is given. Plasma-facing materials from fusion experiments, in particular metal mirrors, are used as a main example for the discussion. Marker experiments using nitrogen-15 or oxygen-18 are specific cases for which the described improved species separation and sensitivity are required. Resilience to radiation damage and significantly improved energy resolution for heavy elements at low energies are additional benefits of the gas ionization chamber over a solid state detector based system.

  1. In situ chamber built for clarifying the relationship between methane hydrate crystal morphology and gas permeability in a thin glass micromodel cell

    NASA Astrophysics Data System (ADS)

    Muraoka, Michihiro; Yamamoto, Yoshitaka

    2017-06-01

    We developed a novel in situ chamber to investigate the relationship between gas hydrate crystal morphology and gas permeability in a glass micromodel that mimics marine sediment. This high-pressure experimental chamber was able to use a thin glass cell without high pressure resistance. The formation of methane hydrate (MH) in the glass micromodel was observed in situ. We investigated the relationship between the MH growth rate and the degree of super cooling ΔT. In addition, we successfully performed the in situ observation of both hydrate morphology and gas permeability measurement simultaneously.

  2. In situ chamber built for clarifying the relationship between methane hydrate crystal morphology and gas permeability in a thin glass micromodel cell.

    PubMed

    Muraoka, Michihiro; Yamamoto, Yoshitaka

    2017-06-01

    We developed a novel in situ chamber to investigate the relationship between gas hydrate crystal morphology and gas permeability in a glass micromodel that mimics marine sediment. This high-pressure experimental chamber was able to use a thin glass cell without high pressure resistance. The formation of methane hydrate (MH) in the glass micromodel was observed in situ. We investigated the relationship between the MH growth rate and the degree of super cooling ΔT. In addition, we successfully performed the in situ observation of both hydrate morphology and gas permeability measurement simultaneously.

  3. Telescopic measurements of backscattered radiation from secondary collimator jaws to a beam monitor chamber using a pair of slits

    SciTech Connect

    Kubo, H.

    1989-03-01

    A contribution to field-size dependent output by backscattered radiation (BSR) from secondary collimator jaws to a beam monitor chamber of a linear accelerator was measured with a Farmer ionization chamber, positioned 200 cm from the source behind a low-melting-point alloy slab with a 10-cm wide slit. Another slit was positioned against the collimator jaws. Both slits were in the form of a 6.3-mm-diam hole in the middle and were aligned to the source. The use of a pair of slits was intended to eliminate any influence on the ion chamber readings due to field-size dependent charge contribution from the flattening filter and collimator jaw forward scattering. In addition, the setup permits to observe the degree of field-size dependence on BSR. Charge measurements from the Therac-20 18-MV x rays showed a 7.5% field-size dependence on BSR whereas 6- and 18-MV x rays from Varian Clinac-1800 showed <2% dependence on BSR. The telescopic method was found to be easy to use and permitted direct determination of BSR contributions.

  4. Telescopic measurements of backscattered radiation from secondary collimator jaws to a beam monitor chamber using a pair of slits.

    PubMed

    Kubo, H

    1989-01-01

    A contribution to field-size dependent output by backscattered radiation (BSR) from secondary collimator jaws to a beam monitor chamber of a linear accelerator was measured with a Farmer ionization chamber, positioned 200 cm from the source behind a low-melting-point alloy slab with a 10-cm wide slit. Another slit was positioned against the collimator jaws. Both slits were in the form of a 6.3-mm-diam hole in the middle and were aligned to the source. The use of a pair of slits was intended to eliminate any influence on the ion chamber readings due to field-size dependent charge contribution from the flattening filter and collimator jaw forward scattering. In addition, the setup permits to observe the degree of field-size dependence on BSR. Charge measurements from the Therac-20 18-MV x rays showed a 7.5% field-size dependence on BSR whereas 6- and 18-MV x rays from Varian Clinac-1800 showed less than 2% dependence on BSR. The telescopic method was found to be easy to use and permitted direct determination of BSR contributions.

  5. Development of an Exhaled Breath Monitoring System with Semiconductive Gas Sensors, a Gas Condenser Unit, and Gas Chromatograph Columns.

    PubMed

    Itoh, Toshio; Miwa, Toshio; Tsuruta, Akihiro; Akamatsu, Takafumi; Izu, Noriya; Shin, Woosuck; Park, Jangchul; Hida, Toyoaki; Eda, Takeshi; Setoguchi, Yasuhiro

    2016-11-10

    Various volatile organic compounds (VOCs) in breath exhaled by patients with lung cancer, healthy controls, and patients with lung cancer who underwent surgery for resection of cancer were analyzed by gas condenser-equipped gas chromatography-mass spectrometry (GC/MS) for development of an exhaled breath monitoring prototype system involving metal oxide gas sensors, a gas condenser, and gas chromatography columns. The gas condenser-GC/MS analysis identified concentrations of 56 VOCs in the breath exhaled by the test population of 136 volunteers (107 patients with lung cancer and 29 controls), and selected four target VOCs, nonanal, acetoin, acetic acid, and propanoic acid, for use with the condenser, GC, and sensor-type prototype system. The prototype system analyzed exhaled breath samples from 101 volunteers (74 patients with lung cancer and 27 controls). The prototype system exhibited a level of performance similar to that of the gas condenser-GC/MS system for breath analysis.

  6. Development of an Exhaled Breath Monitoring System with Semiconductive Gas Sensors, a Gas Condenser Unit, and Gas Chromatograph Columns

    PubMed Central

    Itoh, Toshio; Miwa, Toshio; Tsuruta, Akihiro; Akamatsu, Takafumi; Izu, Noriya; Shin, Woosuck; Park, Jangchul; Hida, Toyoaki; Eda, Takeshi; Setoguchi, Yasuhiro

    2016-01-01

    Various volatile organic compounds (VOCs) in breath exhaled by patients with lung cancer, healthy controls, and patients with lung cancer who underwent surgery for resection of cancer were analyzed by gas condenser-equipped gas chromatography-mass spectrometry (GC/MS) for development of an exhaled breath monitoring prototype system involving metal oxide gas sensors, a gas condenser, and gas chromatography columns. The gas condenser-GC/MS analysis identified concentrations of 56 VOCs in the breath exhaled by the test population of 136 volunteers (107 patients with lung cancer and 29 controls), and selected four target VOCs, nonanal, acetoin, acetic acid, and propanoic acid, for use with the condenser, GC, and sensor-type prototype system. The prototype system analyzed exhaled breath samples from 101 volunteers (74 patients with lung cancer and 27 controls). The prototype system exhibited a level of performance similar to that of the gas condenser-GC/MS system for breath analysis. PMID:27834896

  7. 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

  8. 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...

  9. 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...

  10. 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...

  11. 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...

  12. 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...

  13. 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.

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

    NASA Astrophysics Data System (ADS)

    Pang, xiaobing; Lewis, Alastair; Rickard, Andrew R.; Baeza-Romero, Maria Teresa; Adams, Thomas J.; Ball, Stephen M.; Goodall, Iain C. A.; Monks, Paul S.; Peppe, Salvatore; Ródenas García, Milagros; Sánchez, Pilar; Muñoz, Amalia

    2014-05-01

    A microfluidic lab-on-a-chip derivatisation technique has been developed to measure part per billion (ppbV) mixing ratios of gaseous glyoxal (GLY) and methylglyoxal (MGLY), and the method is compared with other techniques in a smog chamber experiment. The method uses o-(2,3,4,5,6-pentafluorobenzyl) hydroxylamine (PFBHA) as a derivatisation 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 derivatisation 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 derivatised under optimal reaction conditions. The analytical performance shows good accuracy (6.6 % for GLY and 7.5 % for MGLY), suitable precision (< 12.0 %) and method detection limits (MDLs) (75 pptV for GLY and 185 pptV for MGLY) with a time resolution of 30 minutes. These MDLs are below or close to typical concentrations of these compounds observed in ambient air. The microfluidic derivatisation technique would be appropriate for ambient α-dicarbonyl measurements in a range of field environments based on its performance in a large-scale outdoor atmospheric simulation chamber (EUPHORE). The feasibility of the technique was assessed by applying the methodology to quantify of α-dicarbonyls formed during the photo-oxidation of isoprene in the EUPHORE chamber. Good correlations were found between microfluidic measurements and Fourier Transform InfraRed spectroscopy (FTIR) with the correlation coefficient (r2) of 0.84, Broad Band Cavity Enhanced Absorption Spectroscopy (BBCEAS) (r2 = 0.75), solid phase micro extraction (SPME) (r2 = 0.89), and a

  15. On the calibration of a radon exhalation monitor based on the electrostatic collection method and accumulation chamber.

    PubMed

    Tan, Yanliang; Tokonami, Shinji; Hosoda, Masahiro

    2015-06-01

    The radon exhalation rate can be obtained quickly and easily from the evolution of radon concentration over time in the accumulation chamber. Radon monitoring based on the electrostatic collection method is not interfered with by (220)Rn. In this paper, we propose that the difference between radon and (218)Po concentrations in the measurement cell of this kind of radon exhalation monitor is the main system error, and it changes with time and different effective decay constants. Based on the results of simulation experiments, we propose that the calibration factor obtained from the suitable experiment cannot completely correct the system error, even if it is useful to reduce the measurement error. The better way for reducing measurement error is to use the new measurement model which we have proposed in recent years.

  16. A pixel ionization chamber used as beam monitor at the Institut Curie—Centre de Protontherapie de Orsay (CPO)

    NASA Astrophysics Data System (ADS)

    La Rosa, A.; Garella, M. A.; Bourhaleb, F.; Cirio, R.; Donetti, M.; Giordanengo, S.; Givehchi, N.; Marchetto, F.; Martin, F.; Meyroneinc, S.; Peroni, C.; Pittà, G.

    2006-09-01

    The Dipartimento di Fisica Sperimentale and the Istituto Nazionale di Fisica Nucleare (INFN), Torino, in collaboration with the Institut Curie—Centre de Protontherapie de Orsay (CPO), have developed and built a pixel parallel plate ionization chamber to be used as monitor for the proton therapy beam line at the Institut Curie—CPO (Orsay, France). The sensitive area of the detector is (160×160) mm 2, with the anode segmented in 1024 square pixels arranged in a 32×32 matrix; the area of each pixel is (5×5) mm 2. The detector has been placed on the beam line just upstream of the last collimator to monitor the beam shape and to measure the stability and reproducibility of the delivery system. In this paper, we present a detailed description of the detector and the results of a set of preliminary tests.

  17. 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.

  18. Ecliptic method for the determination of backscatter into the beam monitor chambers in photon beams of medical accelerators.

    PubMed

    Sanz, Darío Esteban; Alvarez, Guillermo Daniel; Nelli, Flavio Enrico

    2007-03-21

    A new method to measure the effect of the backscatter into the beam monitor chambers in linear accelerators is introduced from first principles. The technique, applicable to high-energy photon beams, is similar to the well-known telescopic method although here the heavy blocks are replaced by a very small, centred block on the shadow tray, thus the name 'ecliptic method'. This effect, caused mainly by backscattering from the secondary collimators, is known to be an output factor constituent and must be accounted for when detailed calculations involving the machine's head are required. Since its magnitude is generally small, experimental errors might obscure the behaviour of the phenomenon. Consequently, the procedure introduced goes along with an uncertainty assessment. Our theory was confirmed via measurements in cobalt-60 beams, where the studied effect does not contribute to the output factor. Measurements were also performed on our Saturne 41 linear accelerator and the results were qualitatively similar to those described elsewhere. The collimation systems were studied separately by varying one jaw setting while keeping the other at its maximum value. In the light of these results, we deduced an algorithm that can correlate the former data with the effect of backscattering to the beam monitor chambers for any rectangular field within 0.5%, which is of the order of the experimental uncertainty (0.6%). As we show, the experimental procedure is safe, simple, not invasive for the linac and requires only basic dosimetry equipment.

  19. Headspace stir bar sorptive extraction-gas chromatography/mass spectrometry characterization of the diluted vapor phase of cigarette smoke delivered to an in vitro cell exposure chamber.

    PubMed

    Kaur, Navneet; Cabral, Jean-Louis; Morin, André; Waldron, Karen C

    2011-01-14

    Advanced smoke generation systems, such as the Borgwaldt RM20S(®) smoking machine used in combination with the BAT exposure chamber, allow for the generation, dilution and delivery of fresh cigarette smoke to cell or tissue cultures for in vitro cell culture analyses. Recently, our group confirmed that the Borgwaldt RM20S(®) is a reliable tool to generate and deliver repeatable and reproducible exposure concentrations of whole smoke to in vitro cultures. However, the relationship between dose and diluted smoke components found within the exposure chamber has not been characterized. The current study focused on the development of a headspace stir bar sorptive extraction (HSSE) method to chemically characterize some of the vapor phase components of cigarette smoke generated by the Borgwaldt RM20S(®) and collected within a cell culture exposure chamber. The method was based on passive sampling within the chamber by HSSE using a Twister™ stir bar. Following exposure, sorbed analytes were recovered using a thermal desorption unit and a cooled injection system coupled to gas chromatograph/mass spectrometry for identification and quantification. Using the HSSE method, sixteen compounds were identified. The desorption parameters were assessed using ten reference compounds and the following conditions led to the maximal response: desorption temperature of 200°C for 2 min with cryofocussing temperature of -75°C. During transfer of the stir bars to the thermal desorption system, significant losses of analytes were observed as a function of time; therefore, the exposure-to-desorption time interval was kept at the minimum of 10±0.5 min. Repeatability of the HSSE method was assessed by monitoring five reference compounds present in the vapor phase (10.1-12.9% RSD) and n-butyl acetate, the internal standard (18.5% RSD). The smoke dilution precision was found to be 17.2, 6.2 and 11.7% RSD for exposure concentrations of 1, 2 and 5% (v/v) cigarette vapor phase in air

  20. 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.

  1. 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.

  2. 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.

  3. 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.

  4. 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.

  5. Comparison of floating chamber and eddy covariance measurements of lake greenhouse gas fluxes

    NASA Astrophysics Data System (ADS)

    Podgrajsek, E.; Sahlée, E.; Bastviken, D.; Holst, J.; Lindroth, A.; Tranvik, L.; Rutgersson, A.

    2013-11-01

    Fluxes of carbon dioxide (CO2) and methane (CH4) from lakes may have a large impact on the magnitude of the terrestrial carbon sink. Traditionally lake fluxes have been measured using the floating chambers (FC) technique, however, several recent studies use the eddy covariance (EC) method. We present simultaneous flux measurements using both methods at the lake Tämnaren in Sweden during field campaigns in 2011 and 2012. Only very few similar studies exist. For CO2 flux, the two methods agree relatively well during some periods, but deviate substantially at other times. The large discrepancies might be caused by heterogeneity of partial pressure of CO2 (pCO2w) in the EC flux footprint. The methods agree better for CH4 fluxes, it is, however, clear that short-term discontinuous FC measurements are likely to miss important high flux events.

  6. Comparison of floating chamber and eddy covariance measurements of lake greenhouse gas fluxes

    NASA Astrophysics Data System (ADS)

    Podgrajsek, E.; Sahlée, E.; Bastviken, D.; Holst, J.; Lindroth, A.; Tranvik, L.; Rutgersson, A.

    2014-08-01

    Fluxes of carbon dioxide (CO2) and methane (CH4) from lakes may have a large impact on the magnitude of the terrestrial carbon sink. Traditionally lake fluxes have been measured using the floating chamber (FC) technique; however, several recent studies use the eddy covariance (EC) method. We present simultaneous flux measurements using both methods at lake Tämnaren in Sweden during field campaigns in 2011 and 2012. Only very few similar studies exist. For CO2 flux, the two methods agree relatively well during some periods, but deviate substantially at other times. The large discrepancies might be caused by heterogeneity of partial pressure of CO2 (pCO2w) in the EC flux footprint. The methods agree better for CH4 fluxes. It is, however, clear that short-term discontinuous FC measurements are likely to miss important high flux events.

  7. 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.

  8. Flammable gas tank safety program: Technical basis for gas analysis and monitoring

    SciTech Connect

    Sherwood, D.J.

    1995-09-08

    Flammable gases generated in radioactive liquids. Twenty-five high level radioactive liquid waste storage tanks located underground at the Hanford Site are on a Flammable Gas Watch List because they contain waste which tends to retain the gases generated in it until rather large quantities are available for sudden release to the tank head space; if a tank is full it has little dome space, and a flammable concentration of gases could be produced--even if the tank is ventilated. If the waste has no tendency to retain gas generated in it then a continual flammable gas concentration in the tank dome space is established by the gas production rate and the tank ventilation rate (or breathing rate for unventilated tanks); this is also a potential problem for Flammable Gas Watch List tanks, and perhaps other Hanford tanks too. All Flammable Gas Watch List tanks will be fitted with Standard Hydorgen Monitoring Systems so that their behavior can be observed. In some cases, such as tank 241-SY-101, the data gathered from such observations will indicate that tank conditions need to be mitigated so that gas release events are either eliminated or rendered harmless. For example, a mixer pump was installed in tank 241-SY-101; operating the pump stirs the waste, replacing the large gas release events with small releases of gas that are kept below twenty-five percent of the lower flammability limit by the ventilation system. The concentration of hydrogen measured in Hanford waste tanks is greater than that of any other flammable gas. Hydrogen levels measured with a Standard Hydrogen Monitoring System in excess of 0.6 volume percent will cause Westinghouse Hanford Company to consider actions which will decrease the amount of flammable gas in the tank

  9. Consideration of real gas effects and condensation in a spray-combustion rocket-thrust-chamber design tool

    NASA Astrophysics Data System (ADS)

    Frey, M.; Kniesner, B.; Knab, O.

    2011-10-01

    For the prediction of hot gas side heat transfer in rocket thrust chambers, Astrium Space Transportation (ST) uses the second generation multiphase Navier-Stokes solver Rocflam-II. To account for real-gas and condensation effects, pressure-dependent and even multiphase fluid data are included in the chemistry tables used by the code. Thus, the changing fluid properties near the two-phase region as well as transformation from gaseous to liquid and even solid state are reflected properly. Heat flux measurements for a dedicated subscale test campaign with strongly cooled walls show a clearly increasing heat load as soon as the combustion gases condense at the wall, due to the released latent heat of condensation. Corresponding coupled Rocflam-II/CFX simulations show a good quantitative agreement in heat flux for load cases with and without condensation, showing the ability of the code to correctly simulate flows in the real-gas and even inside the two-phase region.

  10. PandaX-III: Searching for neutrinoless double beta decay with high pressure 136Xe gas time projection chambers

    NASA Astrophysics Data System (ADS)

    Chen, Xun; Fu, ChangBo; Galan, Javier; Giboni, Karl; Giuliani, Franco; Gu, LingHui; Han, Ke; Ji, XiangDong; Lin, Heng; Liu, JiangLai; Ni, KaiXiang; Kusano, Hiroki; Ren, XiangXiang; Wang, ShaoBo; Yang, Yong; Zhang, Dan; Zhang, Tao; Zhao, Li; Sun, XiangMing; Hu, ShouYang; Jian, SiYu; Li, XingLong; Li, XiaoMei; Liang, Hao; Zhang, HuanQiao; Zhao, MingRui; Zhou, Jing; Mao, YaJun; Qiao, Hao; Wang, SiGuang; Yuan, Ying; Wang, Meng; Khan, Amir N.; Raper, Neill; Tang, Jian; Wang, Wei; Dong, JiaNing; Feng, ChangQing; Li, Cheng; Liu, JianBei; Liu, ShuBin; Wang, XiaoLian; Zhu, DanYang; Castel, Juan F.; Cebrián, Susana; Dafni, Theopisti; Garza, Javier G.; Irastorza, Igor G.; Iguaz, Francisco J.; Luzón, Gloria; Mirallas, Hector; Aune, Stephan; Berthoumieux, Eric; Bedfer, Yann; Calvet, Denis; d'Hose, Nicole; Delbart, Alain; Diakaki, Maria; Ferrer-Ribas, Esther; Ferrero, Andrea; Kunne, Fabienne; Neyret, Damien; Papaevangelou, Thomas; Sabatié, Franck; Vanderbroucke, Maxence; Tan, AnDi; Haxton, Wick; Mei, Yuan; Kobdaj, Chinorat; Yan, Yu-Peng

    2017-06-01

    Searching for the neutrinoless double beta decay (NLDBD) is now regarded as the topmost promising technique to explore the nature of neutrinos after the discovery of neutrino masses in oscillation experiments. PandaX-III (particle and astrophysical xenon experiment III) will search for the NLDBD of 136Xe at the China Jin Ping Underground Laboratory (CJPL). In the first phase of the experiment, a high pressure gas Time Projection Chamber (TPC) will contain 200 kg, 90% 136Xe enriched gas operated at 10 bar. Fine pitch micro-pattern gas detector (Microbulk Micromegas) will be used at both ends of the TPC for the charge readout with a cathode in the middle. Charge signals can be used to reconstruct the electron tracks of the NLDBD events and provide good energy and spatial resolution. The detector will be immersed in a large water tank to ensure 5 m of water shielding in all directions. The second phase, a ton-scale experiment, will consist of five TPCs in the same water tank, with improved energy resolution and better control over backgrounds.

  11. 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.

  12. Preliminary Design of the Gas Cherenkov Muon Monitors for LBNE

    NASA Astrophysics Data System (ADS)

    Pitcher, Craig

    2011-10-01

    I am performing preliminary research for a future neutrino experiment at Fermilab called the Long Baseline Neutrino Experiment (LBNE). More specifically, I am determining the best geometry for the gas Cherenkov muon monitors. The purpose of the monitors is to measure, at least indirectly, the energy spectrum of the muons in the beam. I use computer software to simulate a realistic muon beam going through the monitors. Muons in the particle beam that go through the monitors emit Cherenkov radiation, and this light is detected by PMTs. I then plot the number of photons detected as a function of the muon's energy that emitted the detected photons. My goal is to have a very narrow peak on this plot. This peak shifts depending on the simulated index of refraction. The best design for the monitors is an L-shaped pipe filled with Freon gas of adjustable density. It is the simplest and cheapest to build of all the designs I tried, and it can accurately recover the muon energy spectrum based solely on the total number of photons detected in each pulse: using simulation data from 5 indices of refraction, I can recover the muon energy spectrum (within the uncertainties) of a beam that has 5 discrete muon energies.

  13. Commercial anesthetic-respiratory gas monitor utilizing Raman spectroscopy

    NASA Astrophysics Data System (ADS)

    Gregonis, Donald E.; Van Wagenen, Richard A.; Coleman, D.; Mitchell, John R.

    1990-11-01

    A commercial gas monitor which utilizes Raman Spectroscopy has been developed to monitor anesthetic and respiratory gases in the hospital operating room. The instrument measures all molecular gases administered by the anesthesiologist in real time with fast response of breath waveform. These gases include carbon dioxide, nitrous oxide, oxygen, nitrogen and various volatile halogenated organic anesthetics, e.g. halothane, isoflurane, enflurane, sevoflurane and desflurane. The key feature of this instrument which allows it to produce adequate Raman signals with a low cost argon ion laser is measuring these gases inside the laser resonant cavity.

  14. Numerical investigations of cooling holes system role in the protection of the walls of a gas turbine combustion chamber

    NASA Astrophysics Data System (ADS)

    Ben Sik Ali, Ahlem; Kriaa, Wassim; Mhiri, Hatem; Bournot, Philippe

    2012-05-01

    Numerical simulations in a gas turbine Swirl stabilized combustor were conducted to investigate the effectiveness of a cooling system in the protection of combustor walls. The studied combustion chamber has a high degree of geometrical complexity related to the injection system as well as the cooling system based on a big distribution of small holes (about 3,390 holes) bored on the flame tube walls. Two cases were considered respectively the flame tube without and with its cooling system. The calculations were carried out using the industrial CFD code FLUENT 6.2. The various simulations made it possible to highlight the role of cooling holes in the protection of the flame tube walls against the high temperatures of the combustion products. In fact, the comparison between the results of the two studied cases demonstrated that the walls temperature can be reduced by about 800°C by the mean of cooling holes technique.

  15. Development of an ultra-fast data-acquisition system for a two-dimensional microstrip gas chamber.

    PubMed

    Ochi, A; Tanimori, T; Nishi, Y; Aoki, S; Nishi, Y

    1998-05-01

    A high-performance data-acquisition system has been developed in order to obtain time-resolved sequential images from a two-dimensional microstrip gas chamber (MSGC). This was achieved using fully digital processing with a synchronized pipeline method. Complex logical circuits for processing large numbers of signals are mounted on a small number of complex programmable logic devices. The system is operated with a 10 MHz synchronous clock, and has the capability of handling more than 3 x 10(6) counts s(-1) for asynchronous events. The system was examined using a 5 x 5 cm MSGC and the recently developed 10 x 10 cm MSGC (1024 outputs); the anticipated performances were achieved.

  16. 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.

  17. 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.

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

    SciTech Connect

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

    2016-08-15

    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{sup 19} cm{sup −3} range well suited for LWFA.

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

    USDA-ARS?s Scientific Manuscript database

    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...

  20. DETECTORS AND EXPERIMENTAL METHODS: Design and construction of the first prototype ionization chamber for CSNS and PA beam loss monitor (BLM) system

    NASA Astrophysics Data System (ADS)

    Xu, Mei-Hang; Tian, Jian-Min; Chen, Chang; Chen, Yuan-Bo; Xu, Tao-Guang; Lu, Shuang-Tong

    2009-02-01

    Design and construction of the first prototype ionization chamber for CSNS and Proton Accelerator (PA) beam loss monitor (BLM) system is reported. The low leakage current (<0.1 pA), good plateau (approx800 V) and linearity range up to 200 Roentgen/h are obtained in the first prototype. All of these give us good experience for further improving the ionization chamber construction.

  1. Sensor validation and fusion for gas turbine vibration monitoring

    NASA Astrophysics Data System (ADS)

    Yan, Weizhong; Goebel, Kai F.

    2003-08-01

    Vibration monitoring is an important practice throughout regular operation of gas turbine power systems and, even more so, during characterization tests. Vibration monitoring relies on accurate and reliable sensor readings. To obtain accurate readings, sensors are placed such that the signal is maximized. In the case of characterization tests, strain gauges are placed at the location of vibration modes on blades inside the gas turbine. Due to the prevailing harsh environment, these sensors have a limited life and decaying accuracy, both of which impair vibration assessment. At the same time bandwidth limitations may restrict data transmission, which in turn limits the number of sensors that can be used for assessment. Knowing the sensor status (normal or faulty), and more importantly, knowing the true vibration level of the system all the time is essential for successful gas turbine vibration monitoring. This paper investigates a dynamic sensor validation and system health reasoning scheme that addresses the issues outlined above by considering only the information required to reliably assess system health status. In particular, if abnormal system health is suspected or if the primary sensor is determined to be faulted, information from available "sibling" sensors is dynamically integrated. A confidence expresses the complex interactions of sensor health and system health, their reliabilities, conflicting information, and what the health assessment is. Effectiveness of the scheme in achieving accurate and reliable vibration evaluation is then demonstrated using a combination of simulated data and a small sample of a real-world application data where the vibration of compressor blades during a real time characterization test of a new gas turbine power system is monitored.

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

    NASA Astrophysics Data System (ADS)

    Pang, X.; Lewis, A. C.; Rickard, A. R.; 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.

    2014-02-01

    A microfluidic lab-on-a-chip derivatisation technique has been developed to measure part per billion (ppbV) mixing ratios of gaseous glyoxal (GLY) and methylglyoxal (MGLY), and the method is compared with other techniques in a smog chamber experiment. The method uses o-(2, 3, 4, 5, 6-pentafluorobenzyl) hydroxylamine (PFBHA) as a derivatisation 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 resulted in a fast and highly efficient derivatisation 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 derivatised under optimal reaction conditions. The analytical performance shows good accuracy (6.6% for GLY and 7.5% for MGLY), suitable precision (<12.0%) with method detection limits (MDLs) of 75 pptV for GLY and 185 pptV for MGLY, with a time resolution of 30 min. These MDLs are below or close to typical concentrations of these compounds observed in ambient air. The feasibility of the technique was assessed by applying the methodology to quantify α-dicarbonyls formed during the photo-oxidation of isoprene in the EUPHORE chamber. Good correlations were found between microfluidic measurements and Fourier Transform InfraRed spectroscopy (FTIR) with a correlation coefficient (r2) of 0.84, Broadband Cavity Enhanced Absorption Spectroscopy (BBCEAS) (r2 = 0.75), solid phase micro extraction (SPME) (r2 = 0.89), and a photochemical chamber box modelling calculation (r2 = 0.79) for GLY measurements. For MGLY measurements, the microfluidic technique showed good agreement with BBCEAS (r2 = 0.87), SPME (r2 = 0.76), and the modeling simulation (r2 = 0.83), FTIR

  3. Clinical assessment of intraarterial blood gas monitor accuracy

    NASA Astrophysics Data System (ADS)

    Aziz, Salim; Spiess, R.; Roby, Paul; Kenny, Margaret

    1993-08-01

    The accuracy of intraarterial blood gas monitoring (IABGM) devices is challenging to assess under routine clinical conditions. When comparing discrete measurements by blood gas analyzer (BGA) to IABGM values, it is important that the BGA determinations (reference method) be as accurate as possible. In vitro decay of gas tensions caused by delay in BGA analysis is particularly problematic for specimens with high arterial oxygen tension (PaO2) values. Clinical instability of blood gases in the acutely ill patient may cause disagreement between BGA and IABGM values because of IABGM response time lag, particularly in the measurement of arterial blood carbon dioxide tension (PaCO2). We recommend that clinical assessments of IABGM accuracy by comparison with BGA use multiple bedside BGA instruments, and that blood sampling only occur during periods when IABGM values appear stable.

  4. Microfabricated BTU monitoring device for system-wide natural gas monitoring.

    SciTech Connect

    Einfeld, Wayne; Manginell, Ronald Paul; Robinson, Alex Lockwood; Moorman, Matthew Wallace

    2005-11-01

    The natural gas industry seeks inexpensive sensors and instrumentation to rapidly measure gas heating value in widely distributed locations. For gas pipelines, this will improve gas quality during transfer and blending, and will expedite accurate financial accounting. Industrial endusers will benefit through continuous feedback of physical gas properties to improve combustion efficiency during use. To meet this need, Sandia has developed a natural gas heating value monitoring instrument using existing and modified microfabricated components. The instrument consists of a silicon micro-fabricated gas chromatography column in conjunction with a catalytic micro-calorimeter sensor. A reference thermal conductivity sensor provides diagnostics and surety. This combination allows for continuous calorimetric determination with a 1 minute analysis time and 1.5 minute cycle time using air as a carrier gas. This system will find application at remote natural gas mining stations, pipeline switching and metering stations, turbine generators, and other industrial user sites. Microfabrication techniques will allow the analytical components to be manufactured in production quantities at a low per-unit cost.

  5. 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.

  6. On baseline determination and gas saturation derivation from downhole electrical monitoring of shallow biogenic gas production

    NASA Astrophysics Data System (ADS)

    Pezard, P. A.; Celerier, B. P.

    2015-12-01

    Adequate hydrogeophysical monitoring of CO2 geological storage remains a challenge as different parameters might be modified during storage. That implies to compare real-time measurements to an adequate baseline. At the Maguelone shallow experimental site a representative baseline for electrical resistivity was built from a large number of downhole geophysical measurements recorded over time. At this coastal site this issue is particularly important due to the production of biogenic gas at shallow depth (< 200 m) from the subsurface sediments.For this, a modified petrophysical model based on the Waxman-Smits model is proposed to estimate gas saturation found to vary up to 7% within shallow sand layers, indicating that natural gas production within the sedimentary pile from biological activity cannot be neglected during gas injection experiments. In the two main reservoirs located at shallow depth (R1 and R2), a variable gas content of 7% and 4% was obtained over short periods of time in the TLL6 and DSO1 boreholes, respectively. The difference might be due to the gentle stratigraphic slope identified from cross hole log and core analyses, TLL6 being located upslope from DSO1. This study also revealed a rapid dynamic mechanism resulting in transfer of biogenic gas from the bottom reservoir (R1) to the top one (R2), possibly due to gas leaking along some of the monitoring boreholes. These sand-rich layers constitute buffer reservoirs for biogenic gases before being released to the atmosphere. Future studies at Maguelone will first focus on biogenic gas sampling from a downhole multi-packer completion in order to identify and quantify the different gas phases produced over time by the sedimentary pile.

  7. Performance of Current-Mode Ion Chambers as Beam Monitors in a Pulsed Cold Neutron Beam for the NPDGamma experiment

    NASA Astrophysics Data System (ADS)

    Gillis, R. Chad

    2006-10-01

    The NPDGamma collaboration has built and commissioned an apparatus to measure the parity-violating gamma asymmetry A in the low energy np capture process n+p->d+ γ. The asymmetry in question is a 10-8 correlation between the spin of the incident (polarized) neutron and the outgoing 2.2 MeV gamma ray. A set of purpose-built, 3He-filled ionization chambers read out in current mode is used to monitor the incident neutron flux, the beam polarization, and the transmission of the liquid para-hydrogen target during the NPDGamma measurements. As will be described in the talk, these beam monitors are simple, reliable, low-noise detectors that have performed excellently for NPDGamma. We have verified that the beam monitor signals can be interpreted to reproduce the known time-of-flight dependence of beam flux from the LANSCE pulsed cold neutron source, and that the neutron beam polarization can be measured at the 2% level from direct measurements of the transmission of the beam through the beam polarizer.

  8. Long-term monitoring of marine gas leakage

    NASA Astrophysics Data System (ADS)

    Spickenbom, Kai; Faber, Eckhard; Poggenburg, Jürgen; Seeger, Christian; Furche, Markus

    2010-05-01

    The sequestration of CO2 in sub-seabed geological formations is one of the Carbon Capture and Storage (CCS) strategies currently under study. Although offshore operations are significantly more expensive than comparable onshore operations, the growing public resistance against onshore CCS projects makes sub-seabed storage a promising option. Even after a thorough review of the geological setting, there is always the possibility of leakage from the reservoir. As part of the EU-financed project CO2ReMoVe (Research, Monitoring, Verification), which aims to develop innovative research and technologies for monitoring and verification of carbon dioxide geological storage, we are working on the development of submarine long-term gas flow monitoring systems. The basic design of the monitoring system builds on our experience in volcano monitoring. Early prototypes were composed of a raft floating on the surface of a mud volcano, carrying sensors for CO2 flux and concentration, data storage and transmission, and power supply by battery-buffered solar panels. The system was modified for installation in open sea by using a buoy instead of a raft and a funnel on the seafloor to collect the gas, connected by a flexible tube. This setup provides a cost-effective solution for shallow waters. However, a buoy interferes with ship traffic, and it is also difficult to adapt this design to greater water depths. These requirements can best be complied by a completely submersed system. A system for unattended long-term monitoring in a marine environment has to be extremely durable. Therefore, we focussed on developing a mechanically and electrically as simple setup as possible, which has the additional advantage of low cost. The system consists of a funnel-shaped gas collector, a sensor head and pressure housings for electronics and power supply. Since this setup is inexpensive, it can be deployed in numbers to cover larger areas. By addition of multi-channel data loggers, data

  9. 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)

  10. Long-term flow monitoring of submarine gas emanations

    NASA Astrophysics Data System (ADS)

    Spickenbom, K.; Faber, E.; Poggenburg, J.; Seeger, C.

    2009-04-01

    One of the Carbon Capture and Storage (CCS) strategies currently under study is the sequestration of CO2 in sub-seabed geological formations. Even after a thorough review of the geological setting, there is the possibility of leaks from the reservoirs. As part of the EU-financed project CO2ReMoVe (Research, Monitoring, Verification), which aims to develop innovative research and technologies for monitoring and verification of carbon dioxide geological storage, we are working on the development of submarine long-term gas flow monitoring systems. Technically, however, these systems are not limited to CO2 but can be used for monitoring of any free gas emission (bubbles) on the seafloor. The basic design of the gas flow sensor system was derived from former prototypes developed for monitoring CO2 and CH4 on mud volcanoes in Azerbaijan. This design was composed of a raft floating on the surface above the gas vent to collect the bubbles. Sensors for CO2 flux and concentration and electronics for data storage and transmission were mounted on the raft, together with battery-buffered solar panels for power supply. The system was modified for installation in open sea by using a buoy instead of a raft and a funnel on the seafloor to collect the gas, which is then guided above water level through a flexible tube. Besides some technical problems (condensed water in the tube, movement of the buoys due to waves leading to biased measurement of flow rates), this setup provides a cost-effective solution for shallow waters. However, a buoy interferes with ship traffic, and it is also difficult to adapt this design to greater water depths. These requirements can best be complied by a completely submersed system. To allow unattended long-term monitoring in a submarine environment, such a system has to be extremely durable. Therefore, we focussed on developing a mechanically and electrically as simple setup as possible, which has the additional advantage of low cost. The system

  11. 78 FR 19605 - Greenhouse Gas Reporting Rule: Revision to Best Available Monitoring Method Request Submission...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-04-02

    ... AGENCY 40 CFR Part 98 Greenhouse Gas Reporting Rule: Revision to Best Available Monitoring Method Request... published a direct final rule, Greenhouse Gas Reporting Rule: Revision to Best Available Monitoring Method... petroleum and natural gas systems source category of the Greenhouse Gas Reporting Rule are required...

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

    DOE PAGES

    Ou, Shiqi; Zhao, Yi; Aaron, Douglas S.; ...

    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

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

    NASA Astrophysics Data System (ADS)

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

    2016-10-01

    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 in 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. 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.

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

    SciTech Connect

    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 in 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.

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

    SciTech Connect

    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 in 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.

  16. High-Density Gas Column Abundance Measurements Using New Low-Cost Autonomous Sensors, A Solution For Gas Flux Monitoring

    NASA Astrophysics Data System (ADS)

    Gordley, L. L.; Marshall, B. T.; Paxton, G.; Lachance, R. L.; Gubeli, J.; Fisher, J.

    2016-12-01

    This presentation describes a new low-cost gas sensor and strategies of grid deployment for continuous monitoring of gas flux. By measuring column abundances using sun, moon and local light sources, with strategically placed grids of such autonomous sensors, the resulting data can be analyzed with dispersion models to continuously monitor gas flux into or out of any area. We describe this pupil imaging gas correlation (PIGC) sensor, recent laboratory test results, and grid deployment and analysis strategies.

  17. Monitoring underground gas storage for seismic risk assessment

    NASA Astrophysics Data System (ADS)

    Guido, Francesco Luigi; Picotti, Vincenzo; Antonellini, Marco

    2013-04-01

    Temporary gas storage facilities play a fundamental role in the design of energy supply. The evaluation and recognition of induced seismicity, geodetic displacements and wellbores damages are their main associated risks that should be minimized for a safe management of these facilities, especially in densely populated areas. Injection and withdrawal of gas into/from a porous reservoir generally lead reservoir rocks to deform. Rock deformation is due to variations of the state of stress of rocks, both in the reservoir and the surrounding: subsidence, wellbore damages and induced or activated seismicity are primary consequences of these variations. In this paper we present a case study on induced deformation by an exploited gas reservoir, converted to temporary natural gas storage since 1994, in North-Eastern Italy. The reservoir, composed by 2 independent carbonatic sandstone intervals, approximately 10 meters thick, and 1400 meters deep, has been exploited since 1983, recording a pressure drop of about 16 MPa. The inversion of gas pressure and volume data, together with a 26 year ground displacement dataset monitoring, allow us to define reservoir deformations, modelled by a semi-analytical method based on an equivalent Eshelby's inclusion problem, able to account for mechanical differences between reservoir and surrounding rocks. Stress field changes, and displacement fields around the reservoir and on the ground mainly represent the results of this modelling. A Coulomb Failure Stress analysis, performed by FEA, was applied to define and evaluate the influence of magnitude and shape of stress field changes on rock stability, highlighting rock volumes that mainly suffer stress changes eventually leading to induced/activated earthquakes. The microseismic monitoring provides then the control on failures and their location. The methodology here used provide a solid base for induced or activated seismicity risk assessment: it provides an easy tool to quantify magnitude

  18. Acquisition of an X-Ray Scattering System with Solid-Gas Reactor Chamber and Ultrafast Detection Capabilities for Research and Instruction in Science and Engineering

    DTIC Science & Technology

    2015-05-18

    2014 31-Jan-2015 Approved for Public Release; Distribution Unlimited Final Report: Acquisition of an X-Ray Scattering System with Solid-Gas Reactor ...Report: Acquisition of an X-Ray Scattering System with Solid-Gas Reactor Chamber and Ultrafast Detection Capabilities for Research and Instruction...the Dean of the College of Science. We wrote a grant proposal to initiate a UTEP – LANL partnership to the Nuclear Regulatory Commission in 2014

  19. Breath acetone monitoring by portable Si:WO3 gas sensors

    PubMed Central

    Righettoni, Marco; Tricoli, Antonio; Gass, Samuel; Schmid, Alex; Amann, Anton; Pratsinis, Sotiris E.

    2013-01-01

    Breath analysis has the potential for early stage detection and monitoring of illnesses to drastically reduce the corresponding medical diagnostic costs and improve the quality of life of patients suffering from chronic illnesses. In particular, the detection of acetone in the human breath is promising for non-invasive diagnosis and painless monitoring of diabetes (no finger pricking). Here, a portable acetone sensor consisting of flame-deposited and in situ annealed, Si-doped epsilon-WO3 nanostructured films was developed. The chamber volume was miniaturized while reaction-limited and transport-limited gas flow rates were identified and sensing temperatures were optimized resulting in a low detection limit of acetone (~20 ppb) with short response (10–15 s) and recovery times (35–70 s). Furthermore, the sensor signal (response) was robust against variations of the exhaled breath flow rate facilitating application of these sensors at realistic relative humidities (80–90%) as in the human breath. The acetone content in the breath of test persons was monitored continuously and compared to that of state-of-the-art proton transfer reaction mass spectrometry (PTR-MS). Such portable devices can accurately track breath acetone concentration to become an alternative to more elaborate breath analysis techniques. PMID:22790702

  20. The high momentum spectrometer drift chambers

    NASA Astrophysics Data System (ADS)

    Abbott, D.; Baker, O. K.; Beaufait, J.; Bennett, C.; Bryant, E.; Carlini, R.; Kross, B.; McCauley, A.; Naing, W.; Shin, T.; Vulcan, W.

    1992-12-01

    The High Momentum Spectrometer in Hall C will use planar drift chambers for charged particle track reconstruction. The chambers are constructed using well understood technology and a conventional gas mixture. Two (plus one spare) drift chambers will be constructed for this spectrometers. Each chamber will contain 6 planes of readout channels. This paper describes the chamber design and gas handling system used.

  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. Flow chamber

    DOEpatents

    Morozov, Victor [Manassas, VA

    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.

  4. Nuclear monitoring by nonradioactive noble gas sampling and analysis

    SciTech Connect

    Fearey, B.L.; Nakhleh, C.W.; Stanbro, W.D.

    1997-10-01

    This is the final report of a two-year, Laboratory Directed Research and Development (LDRD) project at the Los Alamos National Laboratory (LANL). The perceived importance of measuring the xenon and krypton isotopics of nuclear activities has increased substantially in recent years. We have performed a systems analysis and theoretical simulation of the production, atmospheric dispersion, and isotopic abundances of noble-gas fission products, addressing several questions of interest, including: the relative isotopic variation as a function of nuclear fuel composition, reactor operational history, reactor type, distance from stack, and ambient meteorological conditions. Of particular importance in this analysis was the question of back-calculating process parameters of interest given noble-gas isotopic data. An analysis of the effect of measurement uncertainties was also performed. The results of these analyses indicate that this monitoring concept should be experimentally feasible.

  5. Calculation of gas temperature at the outlet of the combustion chamber and in the air-gas channel of a gas-turbine unit by data of acceptance tests in accordance with ISO

    NASA Astrophysics Data System (ADS)

    Kostyuk, A. G.; Karpunin, A. P.

    2016-01-01

    This article describes a high accuracy method enabling performance of the calculation of real values of the initial temperature of a gas turbine unit (GTU), i.e., the gas temperature at the outlet of the combustion chamber, in a situation where manufacturers do not disclose this information. The features of the definition of the initial temperature of the GTU according to ISO standards were analyzed. It is noted that the true temperatures for high-temperature GTUs is significantly higher than values determined according to ISO standards. A computational procedure for the determination of gas temperatures in the air-gas channel of the gas turbine and cooling air consumptions over blade rims is proposed. As starting equations, the heat balance equation and the flow mixing equation for the combustion chamber are assumed. Results of acceptance GTU tests according to ISO standards and statistical dependencies of required cooling air consumptions on the gas temperature and the blade metal are also used for calculations. An example of the calculation is given for one of the units. Using a developed computer program, the temperatures in the air-gas channel of certain GTUs are calculated, taking into account their design features. These calculations are performed on the previously published procedure for the detailed calculation of the cooled gas turbine subject to additional losses arising because of the presence of the cooling system. The accuracy of calculations by the computer program is confirmed by conducting verification calculations for the GTU of the Mitsubishi Comp. and comparing results with published data of the company. Calculation data for temperatures were compared with the experimental data and the characteristics of the GTU, and the error of the proposed method is estimated.

  6. Measured and Monte Carlo simulated electron backscatter to the monitor chamber for the Varian TrueBeam Linac

    NASA Astrophysics Data System (ADS)

    Lloyd, Samantha A. M.; Gagne, Isabelle M.; Bazalova-Carter, Magdalena; Zavgorodni, Sergei

    2016-12-01

    To accurately simulate therapeutic electron beams using Monte Carlo methods, backscatter from jaws into the monitor chamber must be accounted for via the backscatter factor, S b. Measured and simulated values of S b for the TrueBeam are investigated. Two approaches for measuring S b are presented. Both require service mode operation with the dose and pulse forming networking servos turned off in order to assess changes in dose rate with field size. The first approach samples an instantaneous dose rate, while the second approach times the delivery of a fixed number of monitor units to assess dose rate. Dose rates were measured for 6, 12 and 20 MeV electrons for jaw- or MLC-shaped apertures between 1× 1 and 40× 40 cm2. The measurement techniques resulted in values of S b that agreed within 0.21% for square and asymmetric fields collimated by the jaws. Measured values of S b were used to calculate the forward dose component in a virtual monitor chamber using BEAMnrc. Based on this forward component, simulated values of S b were calculated and compared to measurement and Varian’s VirtuaLinac simulations. BEAMnrc results for jaw-shaped fields agreed with measurements and with VirtuaLinac simulations within 0.2%. For MLC-shaped fields, the respective measurement techniques differed by as much as 0.41% and BEAMnrc results differed with measurement by as much as 0.4%, however, all measured and simulated values agreed within experimental uncertainty. Measurement sensitivity was not sufficient to capture the small backscatter effect due to the MLC, and Monte Carlo predicted backscatter from the MLC to be no more than 0.3%. Backscatter from the jaws changed the electron dose rate by up to 2.6%. This reinforces the importance of including a backscatter factor in simulations of electron fields shaped with secondary collimating jaws, but presents the option of ignoring it when jaws are retracted and collimation is done with the MLC.

  7. TIGER TM : Intelligent continuous monitoring of gas turbines

    SciTech Connect

    McKay, I.; Hibbert, J.; Milne, R.; Nicol, C.

    1998-07-01

    The field of condition monitoring has been an area of rapid growth, with many specialized techniques being developed to measure or predict the health of a particular item of plant. Much of the most recent work has gone into the diagnosis of problems on rotating machines through the application of vibration analysis techniques. These techniques though useful can have a number of limiting factors, such as the need to install specialized sensors and measurement equipment, or the limited scope of the type of data measured. It was recognized in 1992, that the surveillance and condition monitoring procedures available for critical plant, such as gas turbines, were not as comprehensive as they might be and that a novel approach was required to give the operator the necessary holistic view of the health of the plant. This would naturally provide an assessment of the maintenance practices required to yield the highest possible availability without the need to install extensive new instrumentation. From the above objective, the TIGER system was designed which utilizes available data from the gas turbine control system or additionally the plant DCS to measure the behavior of the gas turbine and its associated sub systems. These measured parameters are then compared with an internal model of the turbine system and used to diagnose incorrect responses and therefore the item that is at fault, allowing the operator to quickly restart the turbine after a trip or perform condition based maintenance at the next scheduled outage. This philosophy has been built into the TIGER system and the purpose of this paper is to illustrate its functionality and some of the innovative techniques used in the diagnosis of real gas turbine problems. This is achieved by discussing three case studies where TIGER was integral in returning the plant to operation more quickly than can normally be expected.

  8. Continuous monitoring of a changing sample by multiplex gas chromatography

    NASA Technical Reports Server (NTRS)

    Valentin, Jose R.; Hall, Kirsten W.; Becker, Joseph F.

    1990-01-01

    Results are presented from a study in which a continuously changed gaseous sample was monitored by multiplex gas chromatography (MGC), using the exponential dilution (ED) technique of Ritter and Adams (1976) to change the composition and concentration of a gaseous mixture in such a way as to imitate changes in the atmospheric gases sampled by a descending aircraft. A calibration of the MGC system was performed with four different rates of sample dilution, and the errors resulting from various degrees of change in the sample concentration were determined.

  9. Residual-gas-ionization beam profile monitors in RHIC

    SciTech Connect

    Connolly, R.; Fite, J.; Jao, S.; Trabocchi, C.

    2010-05-02

    Four ionization profile monitors (IPMs) are in RHIC to measure vertical and horizontal beam profiles in the two rings. These work by measuring the distribution of electrons produced by beam ionization of residual gas. During the last two years both the collection accuracy and signal/noise ratio have been improved. An electron source is mounted across the beam pipe from the collector to monitor microchannel plate (MCP) aging and the signal electrons are gated to reduce MCP aging and to allow charge replenishment between single-turn measurements. Software changes permit simultaneous measurements of any number of individual bunches in the ring. This has been used to measure emittance growth rates on six bunches of varying intensities in a single store. Also the software supports FFT analysis of turn-by-turn profiles of a single bunch at injection to detect dipole and quadrupole oscillations.

  10. Active Geophysical Monitoring in Oil and Gas Industry

    NASA Astrophysics Data System (ADS)

    Bakulin, A.; Calvert, R.

    2005-12-01

    Effective reservoir management is a Holy Grail of the oil and gas industry. Quest for new technologies is never ending but most often they increase effectiveness and decrease the costs. None of the newcomers proved to be a silver bullet in such a key metric of the industry as average oil recovery factor. This factor is still around 30 %, meaning that 70 % of hydrocarbon reserves are left in the ground in places where we already have expensive infrastructure (platforms, wells) to extract them. Main reason for this inefficiency is our inability to address realistic reservoir complexity. Most of the time we fail to properly characterize our reservoirs before production. As a matter of fact, one of the most important parameters -- permeability -- can not be mapped from remote geophysical methods. Therefore we always start production blind even though reservoir state before production is the simplest one. Once first oil is produced, we greatly complicate the things and quickly become unable to estimate the state and condition of the reservoir (fluid, pressures, faults etc) or oilfield hardware (wells, platforms, pumps) to make a sound next decision in the chain of reservoir management. Our modeling capabilities are such that if we know true state of the things - we can make incredibly accurate predictions and make extremely efficient decisions. Thus the bottleneck is our inability to properly describe the state of the reservoirs in real time. Industry is starting to recognize active monitoring as an answer to this critical issue. We will highlight industry strides in active geophysical monitoring from well to reservoir scale. It is worth noting that when one says ``monitoring" production technologists think of measuring pressures at the wellhead or at the pump, reservoir engineers think of measuring extracted volumes and pressures, while geophysicist may think of change in elastic properties. We prefer to think of monitoring as to measuring those parameters of the

  11. Experimental Study on Pressure Distribution in Upper Flow Path and Gas Blast Angle of Nozzle in Tandem-puffer Interrupting Chamber

    NASA Astrophysics Data System (ADS)

    Shinkai, Takeshi; Udagawa, Keisuke; Suzuki, Katsumi

    Pressure measurement with insulation tubes is successfully performed at the nozzle throat, in the upper flow path and in the thermal room for the two types of tandem-puffer (self-blast chamber) adopting different gas blast angle of nozzle. The pressure rise mechanism with auto-expansion effect of arc is discussed. The pressure rise in the upper flow path and the thermal chamber is driven by propagation of pressure wave from the arc to the thermal chamber. And several types of oscillation caused by rarefaction wave after the pressure wave and multi-reflection of the pressure wave are superposed on the pressure profile. Finally, an influence of the gas blast angle of the nozzle on cooling of stagnation point (thermal interruption capability) is explained based on the results of these measurement and 2-dimensional thermo-fluid analysis. A little larger gas blast angle of the nozzle leads to stronger gas flow to the stagnation point caused by a little larger resistance to the pressure wave and the gas flow.

  12. Application of infrared spectroscopy to monitoring gas insulated high-voltage equipment: electrode material-dependent SF(6) decomposition.

    PubMed

    Kurte, R; Beyer, C; Heise, H M; Klockow, D

    2002-08-01

    Sulfur hexafluoride is a chemically inert gas which is used in gas insulated substations (GIS) and other high-voltage equipment, leading to a significant enhancement of apparatus lifetime and reductions in installation size and maintenance requirements compared to conventional air insulated substations. However, component failures due to aging of the gas through electrical discharges may occur, and on-site monitoring for risk assessment is needed. Infrared spectroscopy was used for the analysis of gaseous by-products generated from electrical discharges in sulfur hexafluoride gas. An infrared monitoring system was developed using a micro-cell coupled to an FTIR spectrometer by silver halide fibers. Partial least-squares calibration was applied by using a limited number of optimally selected spectral variables. Emphasis was placed on the determination of main decomposition products, such as SOF(2), SOF(4), and SO(2)F(2). Besides the different electrical conditions, the material of the plane counter electrode of the discharge chamber was also varied between silver, aluminum, copper, tungsten, or tungsten/copper alloy. For the spark experiments the point electrode was the same material as chosen for the plane electrode, whereas for partial discharges a stainless steel needle was employed. Complementary investigations on the chemical composition within the solid counter electrode material by secondary neutral mass spectrometry (SNMS) were also carried out. Under sparking conditions, the electrode material plays an important role in the decomposition rates of the gas-phase, but no relevant material dependence could be observed under partial discharge conditions.

  13. Development of monitoring and control technology based on trace gas monitoring. Final report

    SciTech Connect

    Liebowitz, B.

    1997-07-01

    Trace gases are generated by many biological reactions. During anaerobic decomposition, trace levels of hydrogen (H{sub 2}) and carbon monoxide (CO) gases are produced. It was shown previously that these trace gases are intrinsically related to the biochemical reactions occurring and, therefore, offer promise for on-line process monitoring and control. This work was designed to test how effectively hydrogen and CO could be to monitor high-rate anaerobic systems that has significant mass transfer and complex hydraulics. An experimental program was designed to examine the behavior of an upflow anaerobic sludge blanket (UASB) reactor system under steady state and in response to organic loading perturbations. The responses of trace gases CO and H{sub 2} were tracked using an on-line, real-time gas-monitoring system linked to a computer-controlled data acquisition package. Data on conventional process parameters such as pH, chemical oxygen demand (COD), volatile fatty acids (VFAs) were concurrently collected. Monitoring of conventional process indicators (i.e., pH, VFA, gas production) and trace gas (H{sub 2} and CO) indicators was conducted using a matrix of nine different steady-state OLRs (4-23 kg COD/m{sup 3} -d) and system HRTs (0.5 to 2.5 days) was performed to determine any correlation among the indicators. Of OLR, HRT, and influent COD, only OLR had any significant influence on the process indicators examined. All parameters except methane increased with increases in OLR; methane decreased with increased OLR. The OLR and gas production rate (GP) were observed to be linearly correlated.

  14. Analysis of the injection process in direct injected natural gas engines. Part 2: Effects of injector and combustion chamber design

    SciTech Connect

    Jennings, M.J.; Jeske, F.R. )

    1994-10-01

    A study of natural gas (NG) direct injection (DI) processes in engines has been performed using multidimensional computational fluid dynamics analysis. The purpose was to investigate the effects of key engine design parameters on the mixing in DI NG engines. Full three-dimensional calculations of injection into a medium heavy-duty diesel engine cylinder were performed. Perturbations on a baseline engine configuration were considered. In spite of single plume axisymmetric injection calculations that show mixing improves as nozzle hole size is reduced: plume merging caused by having too many nozzle holes has a severe negative impact on mixing; and increasing the number of injector holes strengthens plume deflection toward the cylinder head, which also adversely affects mixing. The optimal number of holes for a quiescent engine was found to be that which produces the largest number of separate NG plumes. Increasing the nozzle angle to reduce plume deflection can adversely affect mixing due to reduced jet radial penetration. Increasing the injector tip height is an effective approach to eliminating plume deflection and improving mixing. Extremely high-velocity squish flows, with penetration to the center of the piston bowl, are necessary to have a significant impact on mixing. Possible improvements in mixing can be realized by relieving the center of the piston bowl in typical Mexican hat bowl designs. CFD analysis can effectively be used to optimize combustion chamber geometry by fitting the geometry to computed plume shapes.

  15. Electron microscopic evidence for the myosin head lever arm mechanism in hydrated myosin filaments using the gas environmental chamber.

    PubMed

    Minoda, Hiroki; Okabe, Tatsuhiro; Inayoshi, Yuhri; Miyakawa, Takuya; Miyauchi, Yumiko; Tanokura, Masaru; Katayama, Eisaku; Wakabayashi, Takeyuki; Akimoto, Tsuyoshi; Sugi, Haruo

    2011-02-25

    Muscle contraction results from an attachment-detachment cycle between the myosin heads extending from myosin filaments and the sites on actin filaments. The myosin head first attaches to actin together with the products of ATP hydrolysis, performs a power stroke associated with release of hydrolysis products, and detaches from actin upon binding with new ATP. The detached myosin head then hydrolyses ATP, and performs a recovery stroke to restore its initial position. The strokes have been suggested to result from rotation of the lever arm domain around the converter domain, while the catalytic domain remains rigid. To ascertain the validity of the lever arm hypothesis in muscle, we recorded ATP-induced movement at different regions within individual myosin heads in hydrated myosin filaments, using the gas environmental chamber attached to the electron microscope. The myosin head were position-marked with gold particles using three different site-directed antibodies. The amplitude of ATP-induced movement at the actin binding site in the catalytic domain was similar to that at the boundary between the catalytic and converter domains, but was definitely larger than that at the regulatory light chain in the lever arm domain. These results are consistent with the myosin head lever arm mechanism in muscle contraction if some assumptions are made.

  16. Visualization of Gas-to-Liquid (GTL) Fuel Liquid Length and Soot Formation in the Constant Volume Combustion Chamber

    NASA Astrophysics Data System (ADS)

    Azimov, Ulugbek; Kim, Ki-Seong

    In this research, GTL spray combustion was visualized in an optically accessible quiescent constant-volume combustion chamber. The results were compared with the spray combustion of diesel fuel. Fast-speed photography with direct laser sheet illumination was used to determine the fuel liquid-phase length, and shadowgraph photography was used to determine the distribution of the sooting area in the fuel jet. The results showed that the fuel liquid-phase length of GTL fuel jets stabilized at about 20-22mm from the injector orifice and mainly depended on the ambient gas temperature and fuel volatility. GTL had a slightly shorter liquid length than that of the diesel fuel. This tendency was also maintained when multiple injection strategy was applied. The penetration of the tip of the liquid-phase fuel during pilot injection was a little shorter than the penetration during main injection. The liquid lengths during single and main injections were identical. In the case of soot formation, the results showed that soot formation was mainly affected by air-fuel mixing, and had very weak dependence on fuel volatility.

  17. Design and deployment of low-cost plastic optical fiber sensors for gas monitoring.

    PubMed

    Grassini, Sabrina; Ishtaiwi, Maen; Parvis, Marco; Vallan, Alberto

    2014-12-30

    This paper describes an approach to develop and deploy low-cost plastic optical fiber sensors suitable for measuring low concentrations of pollutants in the atmosphere. The sensors are designed by depositing onto the exposed core of a plastic fiber thin films of sensitive compounds via either plasma sputtering or via plasma-enhanced chemical vapor deposition (PECVD). The interaction between the deposited layer and the gas alters the fiber's capability to transmit the light, so that the sensor can simply be realized with a few centimeters of fiber, an LED and a photodiode. Sensors arranged in this way exhibit several advantages in comparison to electrochemical and optical conventional sensors; in particular, they have an extremely low cost and can be easily designed to have an integral, i.e., cumulative, response. The paper describes the sensor design, the preparation procedure and two examples of sensor prototypes that exploit a cumulative response. One sensor is designed for monitoring indoor atmospheres for cultural heritage applications and the other for detecting the presence of particular gas species inside the RPC (resistive plate chamber) muon detector of the Compact Muon Solenoid (CMS) experiment at CERN in Geneva.

  18. Design and Deployment of Low-Cost Plastic Optical Fiber Sensors for Gas Monitoring

    PubMed Central

    Grassini, Sabrina; Ishtaiwi, Maen; Parvis, Marco; Vallan, Alberto

    2015-01-01

    This paper describes an approach to develop and deploy low-cost plastic optical fiber sensors suitable for measuring low concentrations of pollutants in the atmosphere. The sensors are designed by depositing onto the exposed core of a plastic fiber thin films of sensitive compounds via either plasma sputtering or via plasma-enhanced chemical vapor deposition (PECVD). The interaction between the deposited layer and the gas alters the fiber's capability to transmit the light, so that the sensor can simply be realized with a few centimeters of fiber, an LED and a photodiode. Sensors arranged in this way exhibit several advantages in comparison to electrochemical and optical conventional sensors; in particular, they have an extremely low cost and can be easily designed to have an integral, i.e., cumulative, response. The paper describes the sensor design, the preparation procedure and two examples of sensor prototypes that exploit a cumulative response. One sensor is designed for monitoring indoor atmospheres for cultural heritage applications and the other for detecting the presence of particular gas species inside the RPC (resistive plate chamber) muon detector of the Compact Muon Solenoid (CMS) experiment at CERN in Geneva. PMID:25558990

  19. Medical aerosol propellant interference with infrared anaesthetic gas monitors.

    PubMed

    Levin, P D; Levin, D; Avidan, A

    2004-06-01

    1,1,1,2 Tetrafluoroethane is a hydrofluoroalkane (HFA) that is replacing chlorofluorocarbons (CFC) as a medical aerosol propellant in an attempt to reduce damage to the ozone layer. This study compared the effects of HFA- and CFC-based inhalers on four anaesthetic gas monitoring systems. The HFA- and CFC-based inhalers were activated in close proximity to the sample line of two Datex Ohmeda, an Agilent and a Siemens infrared anaesthetic agent monitoring systems. The effects were recorded on each system for five common anaesthetic agents. The HFA inhaler caused either maximal false positive readings (with the exception of desflurane) or transient measurement failure on all systems. The Datex Ohmeda AS/3 system misidentified the HFA inhaler as carbon dioxide at low concentration (2 +/- 0 mm Hg). The CFC-based inhaler caused a minor false-positive reading (0.4 +/- 0%) for halothane only on the Datex Ohmeda AS/3 system only and was misidentified as carbon dioxide at 33.3 (sd 2.1) mm x Hg and 22.4 (8.9) mm x Hg by the Agilent and Siemens systems. The HFA inhaler adversely affected all equipment tested. The infrared spectra of HFA and the common anaesthetic gases have considerable overlap at the 8-12 microm range that is not shared by the CFCs. The differences in spectral overlap explain the different effects of the HFA and CFC propellants. Anaesthetic gas concentration data may be erroneous using the HFA-based inhalers.

  20. Measurement of back-scattered radiation from micro multileaf collimator into the beam monitor chamber from a dual energy linear accelerator

    PubMed Central

    Muralidhar, K. R.; Murthy, P. Narayana; Sresty, N. V. N. M.; Dixit, Pramod Kumar; Kumar, Rajneesh; Raju, A. K.

    2007-01-01

    Measurements designed to find the collimator backscatter into the beam monitor chamber from Micro Multileaf collimator of 6 MV photon beams of the Siemens Primus linear accelerator were made with the help of dose rate feedback control. The photons and electrons backscattered from the upper and lower secondary collimator jaws give rise to a significant increase in the ion charge measured by monitor chamber. This increase varies between the different accelerators. The output measurements were carried out in air at the isocenter. The effect of collimator backscatter was investigated by measuring the pulse width, number of beam pulses per monitor unit, monitor unit rate and dose for different mMLC openings. These measurements were made with and without dose rate feedback control, i.e., with constant electron beam current in the accelerator. Monitor unit rate (MU/min) was almost constant for all field sizes. The maximum variation between the open and the closed feedback control circuits was 2.5%. There was no difference in pulse width and negligible difference in pulse frequency. Maximum value of backscattered radiation from the micro Multileaf collimator into the beam monitor chamber was found to be 0.5%. PMID:21157537

  1. Development and Evaluation of a Hyperbaric Toxic Gas Monitor (SUBTOX) for Disabled Submarines

    DTIC Science & Technology

    2013-08-01

    precise rates. The travel rate for testing in this study was 0.03 ATA/sec (1 foot of seawater [ fsw ] per second) during both compression and...purity regulator on each of the test gas cylinders outside the chamber to a stainless steel penetrator on the exterior of the chamber wall. Inside the...was built. METHODS Late in 2006, ENMET provided NEDU with the components of the Sensor Test System, and — with Teflon and stainless steel

  2. Metal Oxide Semi-Conductor Gas Sensors in Environmental Monitoring

    PubMed Central

    Fine, George F.; Cavanagh, Leon M.; Afonja, Ayo; Binions, Russell

    2010-01-01

    Metal oxide semiconductor gas sensors are utilised in a variety of different roles and industries. They are relatively inexpensive compared to other sensing technologies, robust, lightweight, long lasting and benefit from high material sensitivity and quick response times. They have been used extensively to measure and monitor trace amounts of environmentally important gases such as carbon monoxide and nitrogen dioxide. In this review the nature of the gas response and how it is fundamentally linked to surface structure is explored. Synthetic routes to metal oxide semiconductor gas sensors are also discussed and related to their affect on surface structure. An overview of important contributions and recent advances are discussed for the use of metal oxide semiconductor sensors for the detection of a variety of gases—CO, NOx, NH3 and the particularly challenging case of CO2. Finally a description of recent advances in work completed at University College London is presented including the use of selective zeolites layers, new perovskite type materials and an innovative chemical vapour deposition approach to film deposition. PMID:22219672

  3. Monitoring Induced Seismicity at an Oil/Gas Field

    NASA Astrophysics Data System (ADS)

    Kuleli, H. S.; Sarkar, S.; Toksoz, M. N.; Al-Kindy, F.; El Hussain, I. W.; Al-Hashmi, S.

    2009-12-01

    Seismicity at an oil/gas field has been monitored with surface and borehole seismic networks. Since the seismic monitoring started in 1999, thousands of events have been recorded, located and analyzed. The “surface” seismic network consists of five stations with seismometers in shallow boreholes at 125-150 m depth. The deep network is made up of five downhole geophone arrays, each with 8 sensors, at depths between 650 m and 1200 m. The shallow network has been in constant operation since 1999 and has recorded about 1500 events. The deep network recorded more than 10,000 events between October 2002 and August 2003. To locate the events, a detailed 1-D velocity model derived from sonic logs was used. Various location methods including NonLinLoc, multi-event grid search and time-difference method were used. The latest uses a library of pre-computed travel time differences for all station pairs and for all potential source locations (Sarkar and Toksoz, 2008). An advantage of using the travel time differences between station pairs is that it eliminates origin time from the location algorithms, thus resolving the depth-origin tradeoff issue. There is no record of any seismic events at the site prior to the initiation of oil field activities. The induced events are more strongly correlated with the gas production rates than with oil production. Events mostly occur on preexisting faults, mapped by 3-D surface seismic. There are two (conjugate) sets of faults in the field. The hypocenters are primarily on the NE-SW striking faults oriented parallel to the maximum regional horizontal stress direction. All events recorded are shallow with focal depth of 400 m to 3000 m. A great majority of the events occur between 800 m and 1100 m depth, closer to the depth of the gas reservoir than to the deeper oil reservoir.

  4. Condition Based Monitoring of Gas Turbine Combustion Components

    SciTech Connect

    Ulerich, Nancy; Kidane, Getnet; Spiegelberg, Christine; Tevs, Nikolai

    2012-09-30

    The objective of this program is to develop sensors that allow condition based monitoring of critical combustion parts of gas turbines. Siemens teamed with innovative, small companies that were developing sensor concepts that could monitor wearing and cracking of hot turbine parts. A magnetic crack monitoring sensor concept developed by JENTEK Sensors, Inc. was evaluated in laboratory tests. Designs for engine application were evaluated. The inability to develop a robust lead wire to transmit the signal long distances resulted in a discontinuation of this concept. An optical wear sensor concept proposed by K Sciences GP, LLC was tested in proof-of concept testing. The sensor concept depended, however, on optical fiber tips wearing with the loaded part. The fiber tip wear resulted in too much optical input variability; the sensor could not provide adequate stability for measurement. Siemens developed an alternative optical wear sensor approach that used a commercial PHILTEC, Inc. optical gap sensor with an optical spacer to remove fibers from the wearing surface. The gap sensor measured the length of the wearing spacer to follow loaded part wear. This optical wear sensor was developed to a Technology Readiness Level (TRL) of 5. It was validated in lab tests and installed on a floating transition seal in an F-Class gas turbine. Laboratory tests indicate that the concept can measure wear on loaded parts at temperatures up to 800{degrees}C with uncertainty of < 0.3 mm. Testing in an F-Class engine installation showed that the optical spacer wore with the wearing part. The electro-optics box located outside the engine enclosure survived the engine enclosure environment. The fiber optic cable and the optical spacer, however, both degraded after about 100 operating hours, impacting the signal analysis.

  5. Development and Evaluation of a Hyperbaric Toxic Gas Monitor (SubTox) for Disabled Submarines

    DTIC Science & Technology

    2013-08-01

    DEVELOPMENT AND EVALUATION OF A HYPERBARIC TOXIC GAS MONITOR (SUBTOX) FOR DISABLED SUBMARINES...HYPERBARIC TOXIC GAS MONITOR (SUBTOX) FOR DISABLED SUBMARINES 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) R. S. Lillo...for monitoring toxic gases on disabled submarines (DISSUBs) rely on chemical detector tubes to determine when submarine escape action levels (SEALs

  6. Trace gas detection and monitoring with the Digital Array Gas-correlation Radiometer (DAGR)

    NASA Astrophysics Data System (ADS)

    Gordley, Larry L.; Hervig, Mark E.; Fish, Chad; McHugh, Martin J.

    2011-05-01

    We present the first results from a Digital Array Gas-correlation Radiometer (DAGR) prototype sensor, and discuss applications in remote sensing of trace gases. The sensor concept is based on traditional and reliable Gas Filter Correlation Radiometry (GFCR), but overcomes the limitations in solar backscatter applications. The DAGR sensor design can be scaled to the size of a digital camera and is ideal for downlooking detection of gases in the boundary layer, where solar backscatter measurements are needed to overcome the lack of thermal contrast in the IR. Ground-based portable DAGR sensors can monitor carbon sequestration sites or industrial facilities. Aircraft or UAV deployment can quickly survey large areas and are particularly well suited for gas leak detection or carbon monitoring. From space-based platforms, Doppler modulation can be exploited to produce an extremely fine spectral resolution with effective resolving power exceeding 100,000. Such space-based DAGR observations could provide near-global sensing of climatically important species such as such as CO2, CO, CH4, O3 and N2O. Planetary science applications include detection and mapping of biomarkers in the Martian atmosphere.

  7. Bakeout Chamber Within Vacuum Chamber

    NASA Technical Reports Server (NTRS)

    Taylor, Daniel M.; Soules, David M.; Barengoltz, Jack B.

    1995-01-01

    Vacuum-bakeout apparatus for decontaminating and measuring outgassing from pieces of equipment constructed by mounting bakeout chamber within conventional vacuum chamber. Upgrade cost effective: fabrication and installation of bakeout chamber simple, installation performed quickly and without major changes in older vacuum chamber, and provides quantitative data on outgassing from pieces of equipment placed in bakeout chamber.

  8. Bakeout Chamber Within Vacuum Chamber

    NASA Technical Reports Server (NTRS)

    Taylor, Daniel M.; Soules, David M.; Barengoltz, Jack B.

    1995-01-01

    Vacuum-bakeout apparatus for decontaminating and measuring outgassing from pieces of equipment constructed by mounting bakeout chamber within conventional vacuum chamber. Upgrade cost effective: fabrication and installation of bakeout chamber simple, installation performed quickly and without major changes in older vacuum chamber, and provides quantitative data on outgassing from pieces of equipment placed in bakeout chamber.

  9. A Modern Automatic Chamber Technique as a Powerful Tool for CH4 and CO2 Flux Monitoring

    NASA Astrophysics Data System (ADS)

    Mastepanov, M.; Christensen, T. R.; Lund, M.; Pirk, N.

    2014-12-01

    A number of similar systems were used for monitoring of CH4 and CO2 exchange by the automatic chamber method in a range of different ecosystems. The measurements were carried out in northern Sweden (mountain birch forest near Abisko, 68°N, 2004-2010), southern Sweden (forest bog near Hässleholm, 56°N, 2007-2014), northeastern Greenland (arctic fen in Zackenberg valley, 74°N, 2005-2014), southwestern Greenland (fen near Nuuk, 64°N, 2007-2014), central Svalbard (arctic fen near Longyearbyen, 78°N, 2011-2014). Those in total 37 seasons of measurements delivered not only a large amount of valuable flux data, including a few novel findings (Mastepanov et al., Nature, 2008; Mastepanov et al., Biogeosciences, 2013), but also valuable experience with implementation of the automatic chamber technique using modern analytical instruments and computer technologies. A range of high resolution CH4 analysers (DLT-100, FMA, FGGA - Los Gatos Research), CO2 analyzers (EGM-4, SBA-4 - PP Systems; Li-820 - Li-Cor Biosciences), as well as Methane Carbon Isotope Analyzer (Los Gatos Research) has shown to be suitable for precise measurements of fluxes, from as low as 0.1 mg CH4 m-1 d-1 (wintertime measurements at Zackenberg, unpublished) to as high as 2.4 g CH4 m-1 d-1 (autumn burst 2007 at Zackenberg, Mastepanov et al., Nature, 2008). Some of these instruments had to be customized to accommodate 24/7 operation in harsh arctic conditions. In this presentation we will explain some of these customizations. High frequency of concentration measurements (1 Hz in most cases) provides a unique opportunity for quality control of flux calculations; on the other hand, this enormous amount of data can be analyzed only using highly automated algorithms. A specialized software package was developed and improved through the years of measurements and data processing. This software automates the data flow from raw concentration data of different instruments and sensors and various status records

  10. [Noninvasive monitoring of gas exchange: methodologic prerequisites and clinical use].

    PubMed

    Kreymann, G; Gottschall, C; Grosser, S; Matthaei, S; Raedler, A; Schubmann, R; Beck, H

    1989-02-01

    The noninvasive determination of the respiratory gas exchange (measurement of oxygen uptake and carbon dioxide delivery) permits the calculation of cardiac output by Fick principle and of the actual energy requirement of the patient (indirect calorimetry). A system is presented for the continuous measurement of oxygen uptake and carbon dioxide delivery, that bases on simple components, which are available on most intensive care units. The methodical problems are discussed and the improvement of the signal of the oxygen sensor by digital signal processing is described. Clinical measurements on 16 patients are presented, whose metabolic rate early after extracorporal circulation was measured. The results reveal, that 4.4 hours after ECC the metabolic rate is close to the calculated basic metabolic rate. They demonstrate the importance of indirect calorimetry as a future bedside monitoring routine.

  11. Electron microscopic evidence for the myosin head lever arm mechanism in hydrated myosin filaments using the gas environmental chamber

    SciTech Connect

    Minoda, Hiroki; Okabe, Tatsuhiro; Inayoshi, Yuhri; Miyakawa, Takuya; Miyauchi, Yumiko; Tanokura, Masaru; Katayama, Eisaku; Wakabayashi, Takeyuki; Akimoto, Tsuyoshi; Sugi, Haruo

    2011-02-25

    Research highlights: {yields} We succeeded in recording structural changes of hydrated myosin cross-bridges. {yields} We succeeded in position-marking the cross-bridges with site-directed antibodies. {yields} We recorded cross-bridge movement at different regions in individual cross-bridge. {yields} The movement was smallest at the cross-bridge-subfragment two boundary. {yields} The results provide evidence for the cross-bridge lever arm mechanism. -- Abstract: Muscle contraction results from an attachment-detachment cycle between the myosin heads extending from myosin filaments and the sites on actin filaments. The myosin head first attaches to actin together with the products of ATP hydrolysis, performs a power stroke associated with release of hydrolysis products, and detaches from actin upon binding with new ATP. The detached myosin head then hydrolyses ATP, and performs a recovery stroke to restore its initial position. The strokes have been suggested to result from rotation of the lever arm domain around the converter domain, while the catalytic domain remains rigid. To ascertain the validity of the lever arm hypothesis in muscle, we recorded ATP-induced movement at different regions within individual myosin heads in hydrated myosin filaments, using the gas environmental chamber attached to the electron microscope. The myosin head were position-marked with gold particles using three different site-directed antibodies. The amplitude of ATP-induced movement at the actin binding site in the catalytic domain was similar to that at the boundary between the catalytic and converter domains, but was definitely larger than that at the regulatory light chain in the lever arm domain. These results are consistent with the myosin head lever arm mechanism in muscle contraction if some assumptions are made.

  12. Noble Gas Measurement and Analysis Technique for Monitoring Reprocessing Facilities

    SciTech Connect

    Charlton, William S

    1999-09-01

    An environmental monitoring technique using analysis of stable noble gas isotopic ratios on-stack at a reprocessing facility was developed. This technique integrates existing technologies to strengthen safeguards at reprocessing facilities. The isotopic ratios are measured using a mass spectrometry system and are compared to a database of calculated isotopic ratios using a Bayesian data analysis method to determine specific fuel parameters (e.g., burnup, fuel type, fuel age, etc.). These inferred parameters can be used by investigators to verify operator declarations. A user-friendly software application (named NOVA) was developed for the application of this technique. NOVA included a Visual Basic user interface coupling a Bayesian data analysis procedure to a reactor physics database (calculated using the Monteburns 3.01 code system). The integrated system (mass spectrometry, reactor modeling, and data analysis) was validated using on-stack measurements during the reprocessing of target fuel from a U.S. production reactor and gas samples from the processing of EBR-II fast breeder reactor driver fuel. These measurements led to an inferred burnup that matched the declared burnup with sufficient accuracy and consistency for most safeguards applications. The NOVA code was also tested using numerous light water reactor measurements from the literature. NOVA was capable of accurately determining spent fuel type, burnup, and fuel age for these experimental results. Work should continue to demonstrate the robustness of this system for production, power, and research reactor fuels.

  13. Optical methods for monitoring harmful gas in animal facilities

    NASA Astrophysics Data System (ADS)

    Zhang, Shirui; Dong, Daming; Zheng, Wengang; Wang, Jihua

    2014-06-01

    Animal facilities produce large amounts of harmful gases such as ammonia, hydrogen sulfide, and methane, many of which have a pungent odor. The harmful gases produced by animal housing not only affect the health of people and livestock but also pollute the air. The detection of the harmful gases can effectively improve efficiency of livestock production and reduce environmental pollution. More and more optical detection methods are applied to the detection of the harmful gases produced by animal housing. This summarizes optical detection methods for monitoring the harmful gases in animal housing recently, including nondispersive infrared gas analyzer, ultraviolet differential optical absorption spectroscopy, Fourier transform infrared spectroscopy, and tunable diode laser absorption spectroscopy. The basic principle and the characteristics of these methods are illustrated and the applications on the detection of harmful gases in animal housing are described. Meanwhile, the research of harmful gases monitoring for livestock production based on these methods were listed. The current situation and future development of the detection methods for harmful gases generated by animal housing were summarized by comparing the advantages and disadvantages of each method.

  14. An MLC-based version for the ecliptic method for the determination of backscatter into the beam monitor chambers in photon beams of medical accelerators.

    PubMed

    Nelli, Flavio Enrico

    2016-03-01

    A very simple method to measure the effect of the backscatter from secondary collimators into the beam monitor chambers in linear accelerators equipped with multi-leaf collimators (MLC) is presented here. The backscatter to the monitor chambers from the upper jaws of the secondary collimator was measured on three beam-matched linacs by means of three methods: this new methodology, the ecliptic method, and assessing the variation of the beam-on time per monitor unit with dose rate feedback disabled. This new methodology was used to assess the backscatter characteristics of asymmetric over-traveling jaws. Excellent agreement between the backscatter values measured using the new methodology introduced here and the ones obtained using the other two methods was established. The experimental values reported here differ by less than 1% from published data. The sensitivity of this novel technique allowed differences in backscatter due to the same opening of the jaws, when placed at different positions on the beam path, to be resolved. The introduction of the ecliptic method has made the determination of the backscatter to the monitor chambers an easy procedure. The method presented here for machines equipped with MLCs makes the determination of backscatter to the beam monitor chambers even easier, and suitable to characterize linacs equipped with over-traveling asymmetric secondary collimators. This experimental procedure could be simply implemented to fully characterize the backscatter output factor constituent when detailed dosimetric modeling of the machine's head is required. The methodology proved to be uncomplicated, accurate and suitable for clinical or experimental environments.

  15. Gas flow meter and method for measuring gas flow rate

    DOEpatents

    Robertson, Eric P.

    2006-08-01

    A gas flow rate meter includes an upstream line and two chambers having substantially equal, fixed volumes. An adjustable valve may direct the gas flow through the upstream line to either of the two chambers. A pressure monitoring device may be configured to prompt valve adjustments, directing the gas flow to an alternate chamber each time a pre-set pressure in the upstream line is reached. A method of measuring the gas flow rate measures the time required for the pressure in the upstream line to reach the pre-set pressure. The volume of the chamber and upstream line are known and fixed, thus the time required for the increase in pressure may be used to determine the flow rate of the gas. Another method of measuring the gas flow rate uses two pressure measurements of a fixed volume, taken at different times, to determine the flow rate of the gas.

  16. Leakage correction estimate for electret ion chamber dielectric material used for long-term environmental gamma monitoring.

    PubMed

    Jones, David F; Paulus, L R

    2008-05-01

    The Idaho Department of Environmental Quality INL Oversight Program (DEQ-INL) operates an environmental gamma radiation detection network consisting of a series of high-pressure ion chambers to provide real-time ambient radiation measurements and a series of passive environmental electret ion chambers to increase coverage area and measure cumulative dose over a calendar quarter. DEQ-INL has identified a consistent over-response of approximately 40% by the electret ion chambers with respect to co-located high-pressure ion chambers since 1998. DEQ-INL conducted a series of three investigations to quantify this over-response. The over-response is likely attributable to a number of factors, including inherent voltage loss by the electret material not due to ionization within the chamber. One aspect of the investigation verified the manufacturer's calibration factor used to convert decrease in voltage to exposure. Additional investigations were performed that identified an average electret voltage loss of 0.2 V d(-1). When this voltage correction was applied to historical environmental data, electret ion chamber response was within 10% of the co-located high-pressure ion chamber response.

  17. Utilizing In-Situ Static Chamber Measurements and UAV Imagery for Integrated Greenhouse Gas Emissions Estimations: Assessing Environmental and Management Impacts on Agricultural Emissions for Two Paired-Watershed Sites in Vermont

    NASA Astrophysics Data System (ADS)

    Barbieri, L.; Peterson, F. S.; Wyngaard, J.

    2015-12-01

    Agricultural greenhouse gas (GHG) emissions contribute to ~10-12% of global anthropogenic emissions. While agriculture is a major source of GHG emissions, there is also great potential for mitigation, as emissions can be reduced by utilizing specific field management and fertilization strategies. This study closely monitors hay and corn fields in Vermont in two paired-watershed sites. Carbon dioxide, nitrous oxide and methane emissions were measured weekly using static chambers and a Photoacoustic Gas Sensor (PAS) across both field management treatments: conventional and mitigation. Accurately quantifying emissions from agricultural landscapes is crucial to develop and implement optimal mitigation strategies, but quantifying landscape-wide emissions is challenging. In this study, we show that both field management treatments and environmental conditions (such as field flooding from rain events) significantly affect GHG emissions, and both can be highly spatially variable even on the field-scale. Monitoring this kind of complexity across a watershed is difficult, as most current emissions quantification techniques, such as static chambers, are localized, point specific and costly. Remote sensing provides an opportunity to monitor landscapes more efficiently and cost effectively. High resolution imagery from an Unmanned Aerial Vehicle (UAV) can also provide opportunities for more accurate watershed-wide estimates of GHG emission rates based on observable agricultural field conditions and management signals, such as field flooding, fertilizer application method, and cover cropping. Satellite imagery, and even the higher resolution aerial imagery used for agricultural monitoring, do not provide the spatial or temporal resolution needed to monitor the on-field complexities that affect GHG emissions. This study combines and compares environmental and management observations from UAV imagery and in-situ field GHG emissions measurements to determine the effectiveness of

  18. The dynamic chamber method: trace gas exchange fluxes (NO, NO2, O3) between plants and the atmosphere in the laboratory and in the field

    NASA Astrophysics Data System (ADS)

    Breuninger, C.; Oswald, R.; Kesselmeier, J.; Meixner, F. X.

    2012-05-01

    We describe a dynamic chamber system to determine reactive trace gas exchange fluxes between plants and the atmosphere under laboratory and, with small modifications, also under field conditions. The system allows measurements of the flux density of the reactive NO-NO2-O3 triad and additionally of the non-reactive trace gases CO2 and H2O. The chambers are made of transparent and chemically inert wall material and do not disturb plant physiology. For NO2 detection we used a highly NO2 specific blue light converter coupled to chemiluminescence detection of the photolysis product, NO. Exchange flux densities derived from dynamic chamber measurements are based on very small concentration differences of NO2 (NO, O3) between inlet and outlet of the chamber. High accuracy and precision measurements are therefore required, and high instrument sensitivity (limit of detection) and the statistical significance of concentration differences are important for the determination of corresponding exchange flux densities, compensation point concentrations, and deposition velocities. The determination of NO2 concentrations at sub-ppb levels (<1 ppb) requires a highly sensitive NO/NO2 analyzer with a lower detection limit (3σ-definition) of 0.3 ppb or better. Deposition velocities and compensation point concentrations were determined by bi-variate weighted linear least-squares fitting regression analysis of the trace gas concentrations, measured at the inlet and outlet of the chamber. Performances of the dynamic chamber system and data analysis are demonstrated by studies of Picea abies L. (Norway Spruce) under field and laboratory conditions. Our laboratory data show that the quality selection criterion based on the use of only significant NO2 concentration differences has a considerable impact on the resulting compensation point concentrations yielding values closer to zero. The results of field experiments demonstrate the need to consider photo-chemical reactions of NO, NO2, and O

  19. Contiuous gas monitoring at the volcano Galeras, Colombia

    NASA Astrophysics Data System (ADS)

    Faber, E.; Morán, C.; Poggenburg, J.; Garzón, G.; Teschner, M.; Weinlich, F. H.

    2003-04-01

    (1) Federal Institute for Geosciences and Natural Resources, Hannover, Germany (e.faber@bgr.de), (2) Instituto de Investigación en Geocientifica, Mineroambiental y Nuclear - INGEOMINAS, San Juan de Pasto, Colombia (3) Instituto de Investigación en Geocientifica, Mineroambiental y Nuclear - INGEOMINAS, Manizales, Colombia A gas monitoring system has been installed on the volcano Galeras in Colombia as part of a multi-parameter station. Gases are extracted from the fumarolic vapour through a short pipe. After the water has been condensed the gas passes over sensors for carbon dioxide, sulphur dioxide and radon. Other parameters measured are temperature of the fumarolic vapour, fumarolic pressure, temperature of the ambient air and the ambient atmospheric pressure. The signals of the sensors are digitised in the electronics. The digital data are transmitted every 6 seconds by a telemetry system to the observatory down in the city of Pasto via a repeater station at the rim of the Galeras. The system at the volcano is powered by batteries connected to solar panels. Data are stored in the observatory, they are plotted and compared with all the other information of the multi-parameter station. Although the various compounds of the gas system are well preserved for the very aggressive environment close to the fumarole some problems still remain: Sulphur often plugs the pipe to the sensors and requires maintenance more often than desired. As the volcano is most of the time in clouds the installed solar power system (about 400 Watts maximum power) does not enable to run the system at the fumarole (consumption about 15 Watts) continuously during all nights. Despite these still existing problems some results have been obtained encouraging us to continue the operation of the system, to further develop the technical quality and to increase the number of fumaroles included into a growing monitoring network. In March 2000 seismic activity in the crater increased accompanied by a

  20. Preliminary Results of an Altitude-Wind-Tunnel Investigation of a TG-100A Gas Turbine-Propeller Engine. V; Combustion-Chamber Characteristics

    NASA Technical Reports Server (NTRS)

    Gensenheyner, Robert M.; Berdysz, Joseph J.

    1947-01-01

    An investigation to determine the performance and operational characteristics of the TG-1OOA gas turbine-propeller engine was conducted in the Cleveland altitude wind tunnel. As part of this investigation, the combustion-chamber performance was determined at pressure altitudes from 5000 to 35,000 feet, compressor-inlet rm-pressure ratios of 1.00 and 1.09, and engine speeds from 8000 to 13,000 rpm. Combustion-chamber performance is presented as a function of corrected engine speed and.correcte& horsepower. For the range of corrected engine speeds investigated, over-all total-pressure-loss ratio, cycle efficiency, ana the frac%ional loss in cycle efficiency resulting from pressure losses in the combustion chambers were unaffected by a change in altitude or compressor-inlet ram-pressure ratio. The scatter of combustion- efficiency data tended to obscure any effect of altitude or ram-pressure ratio. For the range of corrected horse-powers investigated, the total-pressure-loss ratio an& the fractional loss in cycle efficiency resulting from pressure losses in the combustion chambers decreased with an increase in corrected horsepower at a constant corrected engine speed. The combustion efficiency remained constant for the range of corrected horse-powers investigated at all corrected engine speeds.

  1. Preliminary Results of an Altitude-Wind-Tunnel Investigation of an Axial-Flow Gas Turbine-Propeller Engine. 5; Combustion-Chamber Characterisitcs

    NASA Technical Reports Server (NTRS)

    Geisenheyner, Robert M.; Berdysz, Joseph J.

    1948-01-01

    An investigation to determine the performance and operational characteristics of an axial-flow gas turbine-propeller engine was conducted in the Cleveland altitude wind tunnel. As part of this investigation, the combustion-chamber performance was determined at pressure altitudes from 5000 to 35,000 feet, compressor-inlet ram-pressure ratios of 1.00 and 1.09, and engine speeds from 8000 to 13,000 rpm. Combustion-chamber performance is presented as a function of corrected engine speed and corrected horsepower. For the range of corrected engine speeds investigated, overall total-pressure-loss ratio, cycle efficiency, and the fractional loss in cycle efficiency resulting from pressure losses in the combustion chambers were unaffected by a change in altitude or compressor-inlet ram-pressure ratio. For the range of corrected horsepowers investigated, the total-pressure-loss ratio and the fractional loss in cycle efficiency resulting from pressure losses in the combustion chambers decreased with an increase in corrected horsepower at a constant corrected engine speed. The combustion efficiency remained constant for the range of corrected horsepowers investigated at all corrected engine speeds.

  2. Quantification of Gas-Wall Partitioning in Teflon Environmental Chambers Using Rapid Bursts of Low-Volatility Oxidized Species Generated in Situ.

    PubMed

    Krechmer, Jordan E; Pagonis, Demetrios; Ziemann, Paul J; Jimenez, Jose L

    2016-06-07

    Partitioning of gas-phase organic compounds to the walls of Teflon environmental chambers is a recently reported phenomenon than can affect the yields of reaction products and secondary organic aerosol (SOA) measured in laboratory experiments. Reported time scales for reaching gas-wall partitioning (GWP) equilibrium (τGWE) differ by up to 3 orders of magnitude, however, leading to predicted effects that vary from substantial to negligible. A new technique is demonstrated here in which semi- and low-volatility oxidized organic compounds (saturation concentration c* < 100 μg m(-3)) were photochemically generated in rapid bursts in situ in an 8 m(3) environmental chamber, and then their decay in the absence of aerosol was measured using a high-resolution chemical ionization mass spectrometer (CIMS) equipped with an "inlet-less" NO3(-) ion source. Measured τGWE were 7-13 min (rel. std. dev. 33%) for all compounds. The fraction of each compound that partitioned to the walls at equilibrium follows absorptive partitioning theory with an equivalent wall mass concentration in the range 0.3-10 mg m(-3). Measurements using a CIMS equipped with a standard ion-molecule reaction region showed large biases due to the contact of compounds with walls. On the basis of these results, a set of parameters is proposed for modeling GWP in chamber experiments.

  3. 78 FR 11619 - Greenhouse Gas Reporting Rule: Revision to Best Available Monitoring Method Request Submission...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-02-19

    ... AGENCY 40 CFR Part 98 RIN 2060-AR74 Greenhouse Gas Reporting Rule: Revision to Best Available Monitoring... category of the Greenhouse Gas Reporting Rule must submit requests for use of best available monitoring... Division, Office of Atmospheric Programs (MC-6207J), Environmental Protection Agency, 1200 Pennsylvania...

  4. 78 FR 25392 - Greenhouse Gas Reporting Rule: Revision to Best Available Monitoring Method Request Submission...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-05-01

    ... AGENCY 40 CFR Part 98 RIN 2060-AR74 Greenhouse Gas Reporting Rule: Revision to Best Available Monitoring... Greenhouse Gas Reporting Rule must submit requests for use of best available monitoring methods to the... INFORMATION CONTACT: Carole Cook, Climate Change Division, Office of Atmospheric Programs...

  5. Results of vapor space monitoring of flammable gas Watch List tanks

    SciTech Connect

    Wilkins, N.E.

    1997-09-18

    This report documents the measurement of headspace gas concentrations and monitoring results from the Hanford tanks that have continuous flammable gas monitoring. The systems used to monitor the tanks are Standard Hydrogen Monitoring Systems. Further characterization of the tank off-gases was done with Gas Characterization Systems and vapor grab samples. The background concentrations of all tanks are below the action level of 6250 ppm. Other information which can be derived from the measurements (such as generation rate, release rate, and ventilation rate) is also discussed.

  6. Results of Vapor Space Monitoring of Flammable Gas Watch List Tanks

    SciTech Connect

    MCCAIN, D.J.

    2000-09-27

    This report documents the measurement of headspace gas concentrations and monitoring results from the Hanford tanks that have continuous flammable gas monitoring. The systems used to monitor the tanks are Standard Hydrogen Monitoring Systems. Further characterization of the tank off-gases was done with Gas Characterization systems and vapor grab samples. The background concentrations of all tanks are below the action level of 6250 ppm. Other information which can be derived from the measurements (such as generation rate, released rate, and ventilation rate) is also discussed.

  7. Multi-chamber deposition system

    DOEpatents

    Jacobson, Richard L.; Jeffrey, Frank R.; Westerberg, Roger K.

    1989-06-27

    A system for the simultaneous deposition of different coatings onto a thin web within a large volume vacuum chamber is disclosed which chamber is provided with a plurality of deposition chambers in which the different layers are deposited onto the film as its moves from a supply roll to a finished take-up roll of coated web. The deposition chambers provided within the large vacuum chamber are provided with separate seals which minimize back diffusion of any dopant gas from adjacent deposition chambers.

  8. Multi-chamber deposition system

    DOEpatents

    Jacobson, Richard L.; Jeffrey, Frank R.; Westerberg, Roger K.

    1989-10-17

    A system for the simultaneous deposition of different coatings onto a thin web within a large volume vacuum chamber is disclosed which chamber is provided with a plurality of deposition chambers in which the different layers are deposited onto the film as its moves from a supply roll to a finished take-up roll of coated web. The deposition chambers provided within the large vacuum chamber are provided with separate seals which minimize back diffusion of any dopant gas from adjacent deposition chambers.

  9. 78 FR 11585 - Greenhouse Gas Reporting Rule: Revision to Best Available Monitoring Method Request Submission...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-02-19

    ... AGENCY 40 CFR Part 98 RIN 2060-AR74 Greenhouse Gas Reporting Rule: Revision to Best Available Monitoring... natural gas systems source category of the Greenhouse Gas Reporting Rule must submit requests for use of... timely withdrawal notice in the Federal Register to inform the public that this rule will not take...

  10. Operational Experience of the Gas Gain Monitoring system of the CMS RPC muon detectors

    NASA Astrophysics Data System (ADS)

    Colafranceschi, S.; Benussi, L.; Bianco, S.; Fabbri, L.; Giardoni, M.; Ortenzi, B.; Paolozzi, A.; Passamonti, L.; Piccolo, D.; Pierluigi, D.; Ponzio, B.; Russo, A.; Colaleo, A.; Loddo, F.; Maggi, M.; Ranieri, A.; Abbrescia, M.; Iaselli, G.; Marangeli, B.; Natali, S.; Nuzzo, S.; Pugliese, G.; Romano, F.; Roselli, G.; Trentadue, R.; Tupputi, S.; Guida, R.; Polese, G.; Sharma, A.; Cimmino, A.; Lomidze, D.; Paolucci, D.; Baesso, P.; Necchi, M.; Pagano, D.; Ratti, S. P.; Vitulo, P.; Viviani, C.

    2010-05-01

    Performances of the Gas Gain Monitoring system of the CMS RPC muon detectors after one year of operation at the scaled down closed loop recirculation gas system are presented. The GGM is made of 12 single-gap RPC's arranged in a cosmic ray telescope, with charge readout for online monitoring of working point. Preliminary results on sensitivity to gas changes and to environmental variables will be reported on.

  11. Testing surface gas monitoring methods at sites of natural and man-made CO2 seepage in Europe

    NASA Astrophysics Data System (ADS)

    Jones, D.; Lister, R.; Barkwith, A.; Barlow, T.; Shaw, R.; Strutt, M.; Lombardi, S.; Beaubien, S.; Annunziatellis, A.; Graziani, S.

    2011-12-01

    Useful lessons for monitoring techniques and strategies can be learned at natural CO2 seepage sites. Existing methods and new developments can be tested at such sites to assess how useful they would be at geological CO2 storage sites. Such testing is not possible at actual storage sites where there is no leakage. Experience has been gained at the natural CO2 seepage sites near Latera in Italy, the Laacher See in Germany and Florina in Greece. Studies have also been carried out at experimental CO2 injection sites in the UK and Norway and at landfill sites in the UK. The sites have been used as a testing ground for existing and new techniques including open path lasers, eddy covariance, CO2 monitoring stations, flux chambers and in situ and laboratory soil gas analysis. Natural CO2 seepage at the sites tends to occur at gas vents of restricted surface extent. Typically such vents have a diameter of metres to tens of metres. Whilst the vents may align along faults or fractures they occur at small discrete points on such features where permeability is higher. These appear commonly to be associated with fracture intersections. Venting therefore occurs over only a small fraction of the total area of the sites. By analogy this suggests that a surface monitoring strategy for a CO2 storage site needs to include cost effective screening methods that can cover large areas quickly but which are capable of finding small leakage targets. Soil gas concentrations and fluxes vary with time in response to factors such as temperature, pressure, wind speed and soil moisture. This gives rise to diurnal, seasonal and weather system related cycles. Seepage of CO2 can therefore vary over time and this implies the need for continuous monitoring techniques to avoid missing transient releases. Developing legislation for CO2 storage sites (such as the European Union Storage Directive) also requires the quantification of any detected CO2 leakage and this will require an understanding of

  12. Aerosol and gas phase organic acids during aging of secondary organic aerosol from α-pinene in smog chamber experiments

    NASA Astrophysics Data System (ADS)

    Praplan, Arnaud P.; Tritscher, Torsten; Barmet, Peter; Mertes, Peter; Decarlo, Peter F.; Dommen, Josef; Prevot, Andre S. H.; Donahue, Neil M.; Baltensperger, Urs

    2010-05-01

    Organic acids represent an important class of organic compounds in the atmosphere for both the gas and aerosol phase. They are either emitted directly from both biogenic and anthropogenic sources or formed as oxidation products from volatile organic compounds (VOCs) and precursors in the aqueous, gaseous and particle phase (Chebbi & Carlier, 1996) Monoterpenes are a prominent class of VOCs with annual emissions of 127 Tg per year (Guenther et al., 1995). Because of their high formation potential of secondary organic aerosols, several compounds of this class, particularly a-pinene, have been investigated extensively in many laboratory studies. Among other acids, cis-pinic and cis-pinonic acid have been found as products of a-pinene ozonolysis. Ma et al. (2007) published evidence that these organic acids are formed in the gas phase via Criegee Intermediates (CIs). Recently, 3-methyl-1,2,3-butanetricarboxylic acid (MBTCA) was identified by Szmigielski et al. (2007) as a product from a-pinene photooxidation, as well as diaterpenylic acid acetate (Iinuma et al., 2009) and terpenylic acid (Claeys et al., 2009). These compounds could serve as tracers for a-pinene in ambient samples. The present work sets its focus on the fate of a-pinene SOA organic acids under different aging conditions. (1) low NOx concentration (2) high NOx concentration (3) exposure to OH radicals in both dark and lighted environments. a-pinene SOA is produced by ozonolysis without OH scavenger in the PSI smog chamber. It consists of a 27m3 Teflon® bag that can be irradiated by four Xe arc lamps to simulate sunlight (Paulsen et al., 2004). The organic acids are sampled with a wet effluent diffusion denuder (WEDD) and an aerosol collector (AC) for the gas phase and the aerosol particles, respectively. WEDD and AC samples are alternatively concentrated for 30 minutes on a trace anion concentrator (TAC) column (Dionex, Switzerland) and subsequently analyzed by ion chromatography coupled to mass

  13. Engineering Design and Assembly of a Surface Methane and Carbon Dioxide Gas Flux Measurement Chamber With a Case Study on the University of Utah Campus

    NASA Astrophysics Data System (ADS)

    Fenton, Amanda K.

    The purpose of this study was to develop a direct flux emissions measurement method based on existing technology, soil flux chambers, for CH4 and CO2 using lab calibration and field testing. Such chambers were designed for measuring diffuse soil fluxes exclusively, and decades of such measurements indicate the validity of the approach. In this thesis study, the soil chamber was used as a basis for designing a larger chamber capable of handling relatively larger magnitude point fluxes from sewer access covers. The University of Utah campus consists of a series of mixed gravity sewer designs and ages, spanning the past century. Assuming this system was representative of the range of urban gravity sewer infrastructure typical to U.S. cities, a case study was done as part of this thesis. For this work, 11 sewer access covers were analyzed using a specifically designed flux chamber to measure gas fluxes directly from the sewer access covers. Based on these surveys, a preliminary estimate of annual carbon emissions from these 11 access points was determined to be 1.066 Metric Tons CO2 equivalent per year (Mt CO2e). It is recommended that more calibration and continuous surveys of these, and all other sewer access points on campus, are done to facilitate the calculation and cumulative "carbon footprint" of the campus sewer system. Ultimately, the technology developed as part of this thesis work can form the basis of an effective methodology to measure CH4 and CO 2 emissions from sewer lines and possibly other urban infrastructure, and quantify the relative major GHG emissions or "carbon footprint" of such emission sources. (Abstract shortened by ProQuest.).

  14. Leakage detection of Marcellus Shale natural gas at an Upper Devonian gas monitoring well: a 3-d numerical modeling approach.

    PubMed

    Zhang, Liwei; Anderson, Nicole; Dilmore, Robert; Soeder, Daniel J; Bromhal, Grant

    2014-09-16

    Potential natural gas leakage into shallow, overlying formations and aquifers from Marcellus Shale gas drilling operations is a public concern. However, before natural gas could reach underground sources of drinking water (USDW), it must pass through several geologic formations. Tracer and pressure monitoring in formations overlying the Marcellus could help detect natural gas leakage at hydraulic fracturing sites before it reaches USDW. In this study, a numerical simulation code (TOUGH 2) was used to investigate the potential for detecting leaking natural gas in such an overlying geologic formation. The modeled zone was based on a gas field in Greene County, Pennsylvania, undergoing production activities. The model assumed, hypothetically, that methane (CH4), the primary component of natural gas, with some tracer, was leaking around an existing well between the Marcellus Shale and the shallower and lower-pressure Bradford Formation. The leaky well was located 170 m away from a monitoring well, in the Bradford Formation. A simulation study was performed to determine how quickly the tracer monitoring could detect a leak of a known size. Using some typical parameters for the Bradford Formation, model results showed that a detectable tracer volume fraction of 2.0 × 10(-15) would be noted at the monitoring well in 9.8 years. The most rapid detection of tracer for the leak rates simulated was 81 days, but this scenario required that the leakage release point was at the same depth as the perforation zone of the monitoring well and the zones above and below the perforation zone had low permeability, which created a preferred tracer migration pathway along the perforation zone. Sensitivity analysis indicated that the time needed to detect CH4 leakage at the monitoring well was very sensitive to changes in the thickness of the high-permeability zone, CH4 leaking rate, and production rate of the monitoring well.

  15. Blood gas-analyses in patients with cystic fibrosis to estimate hypoxemia during exposure to high altitudes in a hypobaric-chamber.

    PubMed

    Rose, D M; Fleck, B; Thews, O; Kamin, W E

    2000-01-26

    Patients with cystic fibrosis (CF) represent a special risk for commercial airlines. Even on ground conditions the oxygen partial pressure (paO subset2) of these patients is partially clearly reduced. The reduced air pressure on board of an airplane can cause a drop of the paO subset2 to a critical point (below 50 mmHg) during a flight. Therefore, medical assistance or at least oxygen-supply over a longer time period could be necessary. Aim of this study was to investigate reaction and clinical outcome of patients with CF during a hypobaric-chamber-flight at altitudes of 2. 000 and 3.000 m to appraise their risk for a flight-trip. 10 CF-patients (age 19-35 years, mean age 30 y) were investigated in a hypobaric chamber prior to an already booked flight-trip to the Baleares (Spain). Lung-function, oxygen saturation (SO subset2) and paO subset2 by pressure adjusted blood gas analysis were measured on ground level, at 2.000 m and 3.000 m pressure-altitude. Forced expiratory vital capacity (FVC) over the entire group was 2. 9 l (range 1.4 to 4.0 l), forced expiratory 1-second volume (FEV subset1) 2.08 l/sec (range: 1.22 to 3.61 l/sec). Values dropped slightly at 3.000 m chamber altitude (VC=2.7 l, FEV subset1=1.95 l/sec). SO subset2 decreased from 95 % on ground to 89% at 2.000 m and 86 % at 3.000 m chamber altitude. paO2 decreased from 79.5 mmHg at ground level to 60 mmHg at 2000m and 45.5 mmHg at 3.000 m. Only one patient with a paO subset2 of 52 mmHg didn t fall below the critical flight limit of 50 mmHg. No patient felt below a paO subset2 of 40 mmHg. No patient experienced dyspnea during the chamber flight. Two patients without subjective symptoms before the chamber flight developed mild ear blocks during descent presumably due to swollen polyps. Complaints improved quickly by applying decongestant nose-spray. - The results of the chamber flights indicate that chronically adapted adult lung disease patients without accompanying heart disease and a paO subset2 of

  16. Monitoring the Groningen gas field by seismic noise interferometry

    NASA Astrophysics Data System (ADS)

    Zhou, Wen; Paulssen, Hanneke

    2017-04-01

    The Groningen gas field in the Netherlands is the world's 7th largest onshore gas field and has been producing from 1963. Since 2013, the year with the highest level of induced seismicity, the reservoir has been monitored by two geophone strings at reservoir level at about 3 km depth. For borehole SDM, 10 geophones with a natural frequency of 15-Hz are positioned from the top to bottom of the reservoir with a geophone spacing of 30 m. We used seismic interferometry to determine, as accurately as possible, the inter-geophone P- and S-wave velocities from ambient noise. We used 1-bit normalization and spectral whitening, together with a bandpass filter from 3 to 400 Hz. After that, for each station pair, the normalized cross-correlation was calculated for 6 seconds segments with 2/3 overlap. These segmented cross-correlations were stacked for every 1 hour, 24(hours)*33(days) segments were obtained for each station pair. The cross-correlations show both day-and-night and weekly variations reflecting fluctuations in cultural noise. The apparent P-wave travel time for each geophone pair is measured from the maximum of the vertical component cross-correlation for each of the hourly stacks. Because the distribution of these (24*33) picked travel times is not Gaussian but skewed, we used Kernel density estimations to obtain probability density functions of the travel times. The maximum likelihood travel times of all the geophone pairs was subsequently used to determine inter-geophone P-wave velocities. A good agreement was found between our estimated P velocity structure and well logging data, with difference less than 5%. The S-velocity structure was obtained from the east-component cross-correlations. They show both the direct P- and S-wave arrivals and, because of the interference, the inferred S-velocity structure is less accurate. From the 9(3x3)-component cross-correlations for all the geophone pairs, not only the direct P and S waves can be identified, but also

  17. Exposure chamber

    DOEpatents

    Moss, Owen R.; Briant, James K.

    1983-01-01

    An exposure chamber includes an imperforate casing having a fluid inlet at the top and an outlet at the bottom. A single vertical series of imperforate trays is provided. Each tray is spaced on all sides from the chamber walls. Baffles adjacent some of the trays restrict and direct the flow to give partial flow back and forth across the chambers and downward flow past the lowermost pan adjacent a central plane of the chamber.

  18. Optimization of a closed-loop gas system for the operation of Resistive Plate Chambers at the Large Hadron Collider experiments

    NASA Astrophysics Data System (ADS)

    Capeans, M.; Glushkov, I.; Guida, R.; Hahn, F.; Haider, S.

    2012-01-01

    Resistive Plate Chambers (RPCs), thanks to their fast time resolution (˜1 ns), suitable space resolution (˜1 cm) and low production cost (˜50 €/m2), are widely employed for the muon trigger systems at the Large Hadron Collider (LHC). Their large detector volume (they cover a surface of about 4000 m2 equivalent to 16 m3 of gas volume both in ATLAS and CMS) and the use of a relatively expensive Freon-based gas mixture make a closed-loop gas circulation unavoidable. It has been observed that the return gas of RPCs operated in conditions similar to the difficult experimental background foreseen at LHC contains a large amount of impurities potentially dangerous for long-term operation. Several gas-cleaning agents are currently in use in order to avoid accumulation of impurities in the closed-loop circuits. We present the results of a systematic study characterizing each of these cleaning agents. During the test, several RPCs were operated at the CERN Gamma Irradiation Facility (GIF) in a high radiation environment in order to observe the production of typical impurities: mainly fluoride ions, molecules of the Freon group and hydrocarbons. The polluted return gas was sent to several cartridges, each containing a different cleaning agent. The effectiveness of each material was studied using gas chromatography and mass-spectrometry techniques. Results of this test have revealed an optimized configuration of filters that is now under long-term validation.Gas optimization studies are complemented with a finite element simulation of gas flow distribution in the RPCs, aiming at its eventual optimization in terms of distribution and flow rate.

  19. Fracture toughness of Al2O3/ZrSiO4 coatings obtained by multi-chamber gas-dynamic accelerator

    NASA Astrophysics Data System (ADS)

    Arseenko, M. Yu; Kovaleva, M. G.; Prozorova, M. S.; Vagina, O. N.; Yapryntsev, M. N.

    2017-05-01

    In the current work the research of fracture toughness of Al2O3/xZrSiO4 composite coatings have been realized using automatic system for microhardness analysis. Al2O3/xZrSiO4 (x = 0, 3, 25 wt. %) coatings were produced from a mixture of cheap raw materials (alumina and zircon ZrSiO4) on the surface of stainless steels by a new multi-chamber gas-dynamic accelerator. It has been experimentally established that adding of ZrSiO4 increases fracture toughness of alumina coatings.

  20. Aging in the large CDF axial drift chamber

    SciTech Connect

    Allspach, D.; Ambrose, D.; Binkley, M.; Bromberg, C.; Burkett, K.; Kephart, R.; Madrak, R.; Miao, T.; Mukherjee, A.; Roser, R.; Wagner, R.L. /Fermilab

    2004-12-01

    The Central Outer Tracker (COT) is a large axial drift chamber in the Collider Detector at Fermilab operating with a gas mixture that is 50/50 argon/ethane with an admixture of 1.7% isopropanol. In its first two years of operation the COT showed unexpected aging with the worst parts of the chamber experiencing a gain loss of {approx}50% for an accumulated charge of {approx}35 mC/cm. By monitoring the pulse height of hits on good tracks, it was possible to determine the gain as a function of time and location in the chamber. In addition, the currents of the high voltage supplies gave another monitor of chamber gain and its dependence on the charge deposition rate. The aging was worse on the exhaust end of the chamber consistent with polymer buildup as the gas flows through the chamber. The distribution in azimuth suggests that aging is enhanced at lower temperatures, but other factors such as gas flow patterns may be involved. Elemental and molecular analysis of the sense wires found a coating that is mostly carbon and hydrogen with a small amount of oxygen; no silicon or other contaminants were identified. High resolution electron microscope pictures of the wire surface show that the coating is smooth with small sub-micron nodules. In the course of working with the chamber gas system, we discovered a small amount of O{sub 2} is enough to reverse the aging. Operating the chamber with {approx}100 ppm of O{sub 2} reversed almost two years of gain loss in less than 10 days while accumulating {le} 2 mC/cm.

  1. Ethylene monitoring and control system

    NASA Technical Reports Server (NTRS)

    Nelson, Bruce N. (Inventor); Richard, II, Roy V. (Inventor); Kane, James A. (Inventor)

    2001-01-01

    A system that can accurately monitor and control low concentrations of ethylene gas includes a test chamber configured to receive sample gas potentially containing an ethylene concentration and ozone, a detector configured to receive light produced during a reaction between the ethylene and ozone and to produce signals related thereto, and a computer connected to the detector to process the signals to determine therefrom a value of the concentration of ethylene in the sample gas. The supply for the system can include a four way valve configured to receive pressurized gas at one input and a test chamber. A piston is journaled in the test chamber with a drive end disposed in a drive chamber and a reaction end defining with walls of the test chamber a variable volume reaction chamber. The drive end of the piston is pneumatically connected to two ports of the four way valve to provide motive force to the piston. A manifold is connected to the variable volume reaction chamber, and is configured to receive sample gasses from at least one of a plurality of ports connectable to degreening rooms and to supply the sample gas to the reactive chamber for reaction with ozone. The apparatus can be used to monitor and control the ethylene concentration in multiple degreening rooms.

  2. Ethylene monitoring and control system

    NASA Technical Reports Server (NTRS)

    Nelson, Bruce N. (Inventor); Richard, II, Roy V. (Inventor); Kanc, James A. (Inventor)

    2000-01-01

    A system that can accurately monitor and control low concentrations of ethylene gas includes a test chamber configured to receive sample gas potentially containing an ethylene concentration and ozone, a detector configured to receive light produced during a reaction between the ethylene and ozone and to produce signals related thereto, and a computer connected to the detector to process the signals to determine therefrom a value of the concentration of ethylene in the sample gas. The supply for the system can include a four way valve configured to receive pressurized gas at one input and a test chamber. A piston is journaled in the test chamber with a drive end disposed in a drive chamber and a reaction end defining with walls of the test chamber a variable volume reaction chamber. The drive end of the piston is pneumatically connected to two ports of the four way valve to provide motive force to the piston. A manifold is connected to the variable volume reaction chamber, and is configured to receive sample gasses from at least one of a plurality of ports connectable to degreening rooms and to supply the sample gas to the reactive chamber for reaction with ozone. The apparatus can be used to monitor and control the ethylene concentration in multiple degreening rooms.

  3. Applicability of Monte-Carlo Simulation to Equipment Design of Radioactive Noble Gas Monitor

    NASA Astrophysics Data System (ADS)

    Sakai, Hirotaka; Hattori, Kanako; Umemura, Norihiro

    In the nuclear facilities, radioactive noble gas is continuously monitored by using the radioactive noble gas monitor with beta-sensitive plastic scintillation radiation detector. The detection efficiency of the monitor is generally calibrated by using a calibration loop and standard radioactive noble gases such as 85Kr. In this study, the applicability of PHITS to the equipment design of the radioactive noble gas monitor was evaluated by comparing the calculated results to the test results obtained by actual calibration loop tests to simplify the radiation monitor design evaluation. It was confirmed that the calculated results were well matched to the test results of the monitor after the modeling. In addition, the key parameters for equipment design, such as thickness of detector window or depth of the sampler, were also specified and evaluated.

  4. New integrated monitoring and control system for disaster gas application in coal mine

    NASA Astrophysics Data System (ADS)

    Zhao, Deng-yu; Lai, Xing-ping; Ji, Chang-fa; Xi, Hong-jun; Bo, Zhang; Liu, Chen

    2017-04-01

    This paper introduces the composition, working principle and characteristics of the new gas monitoring system, which are used to monitor the gas in the gob area and working face of the mine in real time. According to the oxygen concentration, the spontaneous combustion of gob area “three zones” was determined and divided. In order to carry out disaster early warning, the methane and carbon monoxide super gas concentration changes were studied and analyzed. And the variation law of gas concentration in gob area and coal face in coal mining was obtained. This study provides reference for the follow-up fire prevention and production.

  5. Performance evaluation of a high-sensitivity tritium gas monitor using a pulse-shaping analyzer

    SciTech Connect

    Kawano, T.; Yamano, T.; Yamada, K.; Tanaka, M.; Asakura, Y.; Uda, T.

    2008-07-15

    A tritium gas monitor was developed by applying several techniques including pulse shape analysis. The optimum analyzer values were determined for parameters such as the bias (voltage) applied to the detector, counting gas flow rate, and mixing ratio of sample air to counting gas using an enclosed tritium reference source. After applying these optimized parameters, the factor for converting counting rate to tritium concentration was determined by conducting an experiment using tritiated methane gas. Finally, the detection limit of the monitor for air samples containing tritium was determined based on the conversion factor. (authors)

  6. Long-term autonomous volcanic gas monitoring with Multi-GAS at Mount St. Helens, Washington, and Augustine Volcano, Alaska

    NASA Astrophysics Data System (ADS)

    Kelly, P. J.; Ketner, D. M.; Kern, C.; Lahusen, R. G.; Lockett, C.; Parker, T.; Paskievitch, J.; Pauk, B.; Rinehart, A.; Werner, C. A.

    2015-12-01

    In recent years, the USGS Volcano Hazards Program has worked to implement continuous real-time in situ volcanic gas monitoring at volcanoes in the Cascade Range and Alaska. The main goal of this ongoing effort is to better link the compositions of volcanic gases to other real-time monitoring data, such as seismicity and deformation, in order to improve baseline monitoring and early detection of volcanic unrest. Due to the remote and difficult-to-access nature of volcanic-gas monitoring sites in the Cascades and Alaska, we developed Multi-GAS instruments that can operate unattended for long periods of time with minimal direct maintenance from field personnel. Our Multi-GAS stations measure H2O, CO2, SO2, and H2S gas concentrations, are comprised entirely of commercial off-the-shelf components, and are powered by small solar energy systems. One notable feature of our Multi-GAS stations is that they include a unique capability to perform automated CO2, SO2, and H2S sensor verifications using portable gas standards while deployed in the field, thereby allowing for rigorous tracking of sensor performances. In addition, we have developed novel onboard data-processing routines that allow diagnostic and monitoring data - including gas ratios (e.g. CO2/SO2) - to be streamed in real time to internal observatory and public web pages without user input. Here we present over one year of continuous data from a permanent Multi-GAS station installed in August 2014 in the crater of Mount St. Helens, Washington, and several months of data from a station installed near the summit of Augustine Volcano, Alaska in June 2015. Data from the Mount St. Helens Multi-GAS station has been streaming to a public USGS site since early 2015, a first for a permanent Multi-GAS site. Neither station has detected significant changes in gas concentrations or compositions since they were installed, consistent with low levels of seismicity and deformation.

  7. A novel in-situ method for real-time monitoring of gas transport in soil

    NASA Astrophysics Data System (ADS)

    Laemmel, Thomas; Maier, Martin; Schack-Kirchner, Helmer; Lang, Friederike

    2017-04-01

    Gas exchange between soil and atmosphere is important for the biogeochemistry of soils. Gas transport in soil is commonly assumed to be governed by molecular diffusion and is usually described by the soil gas diffusion coefficient DS characterizing the ability of the soil to "transport passively" gas through the soil. One way to determine DS is sampling soil cores in the field and measuring DS in the lab. Unfortunately this method is destructive and laborious. Moreover, a few previous field studies identified other gas transport processes in soil to significantly enhance the diffusive gas transport. However, until now, no method is available to measure gas transport in situ in the soil. We developed a novel method to monitor gas transport in soil in situ. The method includes a custom made gas sampling device, the continuous injection of an inert tracer gas and inverse gas transport modelling in the soil. The gas sampling device has several sampling depths and can be easily installed into a vertical hole drilled by an auger, which allows for fast installation of the system. Helium (He) as inert tracer gas was injected continuously at the lower end of the device. The resulting steady state distribution of He was used to deduce the depth profile of DS. Gas transport in the soil surrounding the gas-sampling-device/soil system was modeled using the Finite Element Modeling program COMSOL . We tested our new method both in the lab and during two short field studies and compared the results with a reference method using soil cores. DS profiles obtained by our in-situ method were consistent with DS profiles determined based on soil core analyses. During a longer monitoring field campaign, typical soil-moisture effects upon gas diffusivity such as an increase during a drying period or a decrease after rain could be observed consistently. Under windy conditions we additionally measured for the first time the direct enhancement of gas transport in soil due to wind

  8. Comparison of a Gas Chromatograph and a Cavity Ringdown Spectrometer for Flux Quantification of Nitrous Oxide, Carbon Dioxide and Methane in Closed Soil Chambers

    NASA Astrophysics Data System (ADS)

    Saad, Nabil; Jacobson, Gloria; He, Yongang; Herman, Don; Silver, Whendee; Dang, Heather; Fleck, Derek

    2014-05-01

    The study of the three predominant greenhouse gasses effecting global climate change,CO2, CH4 and N2O, has become increasingly important in ecological and agricultural soil research. It is essential for current and future atmospheric greenhouse gas budgets to reduce the uncertainty of greenhouse gas soil fluxes in a variety of environments and climates. Traditional soil flux experiments using the closed chamber and discrete sampling for Gas Chromatograph ("GC") analysis cannot sufficiently capture the large temporal variation in soil gas fluxes, which can lead to large errors in ecosystem flux models. Realtime, simultaneous measurement of these gases should provide easier and more comprehensive and precise chamber flux measurements. We provide a comparison of the GC sampling method to a closed loop, continuous flowsystem coupled with a Picarro G2508 Cavity Ringdown Spectrometer to quantify the flux of CO2, CH4 and N2O. The Picarro analyzer has a data rate of approximately 6 seconds for allthree gases, which gives a much higher temporal resolution than discrete sampling (performed every 8-15 minutes). This work will compare GC and Picarro G2508 soil flux measurement results from three different soil environments. Details on the system configuration and sampling methodology effects on flux errors will also be discussed. We will show that by reducing the systematic error due to sample preparation for the GC, the continuous flow measurement of the Picarro G2508 field deployable analyzer can significantly increase the measurement precision of respiration rates of N2O, CH4 and CO2. It is noteworthy that the Picarro analyzer also simultaneously measures the concentration of ammonia (NH3) and water, and these results will also be discussed.

  9. Vertical two chamber reaction furnace

    DOEpatents

    Blaugher, Richard D.

    1999-03-16

    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.

  10. Vertical two chamber reaction furnace

    DOEpatents

    Blaugher, R.D.

    1999-03-16

    A vertical two chamber reaction furnace is disclosed. 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 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.

  11. Comparative toxicity of fumigants and a phosphine synergist using a novel containment chamber for the safe generation of concentrated phosphine gas.

    PubMed

    Valmas, Nicholas; Ebert, Paul R

    2006-12-27

    With the phasing out of ozone-depleting substances in accordance with the United Nations Montreal Protocol, phosphine remains as the only economically viable fumigant for widespread use. However the development of high-level resistance in several pest insects threatens the future usage of phosphine; yet research into phosphine resistance mechanisms has been limited due to the potential for human poisoning in enclosed laboratory environments. Here we describe a custom-designed chamber for safely containing phosphine gas generated from aluminium phosphide tablets. In an improvement on previous generation systems, this chamber can be completely sealed to control the escape of phosphine. The device has been utilised in a screening program with C. elegans that has identified a phosphine synergist, and quantified the efficacy of a new fumigant against that of phosphine. The phosphine-induced mortality at 20 degrees C has been determined with an LC(50) of 732 ppm. This result was contrasted with the efficacy of a potential new botanical pesticide dimethyl disulphide, which for a 24 hour exposure at 20 degrees C is 600 times more potent than phosphine (LC(50) 1.24 ppm). We also found that co-administration of the glutathione depletor diethyl maleate (DEM) with a sublethal dose of phosphine (70 ppm, gas generation chamber. We have also identified a novel phosphine synergist, the glutathione depletor DEM, suggesting an effective pathway to be targeted in future synergist research; as well as quantifying the efficacy of a potential alternative to phosphine, dimethyl disulphide.

  12. Comparative Toxicity of Fumigants and a Phosphine Synergist Using a Novel Containment Chamber for the Safe Generation of Concentrated Phosphine Gas

    PubMed Central

    Valmas, Nicholas; Ebert, Paul R.

    2006-01-01

    Background With the phasing out of ozone-depleting substances in accordance with the United Nations Montreal Protocol, phosphine remains as the only economically viable fumigant for widespread use. However the development of high-level resistance in several pest insects threatens the future usage of phosphine; yet research into phosphine resistance mechanisms has been limited due to the potential for human poisoning in enclosed laboratory environments. Principal Findings Here we describe a custom-designed chamber for safely containing phosphine gas generated from aluminium phosphide tablets. In an improvement on previous generation systems, this chamber can be completely sealed to control the escape of phosphine. The device has been utilised in a screening program with C. elegans that has identified a phosphine synergist, and quantified the efficacy of a new fumigant against that of phosphine. The phosphine-induced mortality at 20°C has been determined with an LC50 of 732 ppm. This result was contrasted with the efficacy of a potential new botanical pesticide dimethyl disulphide, which for a 24 hour exposure at 20°C is 600 times more potent than phosphine (LC50 1.24 ppm). We also found that co-administration of the glutathione depletor diethyl maleate (DEM) with a sublethal dose of phosphine (70 ppm, gas generation chamber. We have also identified a novel phosphine synergist, the glutathione depletor DEM, suggesting an effective pathway to be targeted in future synergist research; as well as quantifying the efficacy of a potential alternative to phosphine, dimethyl disulphide. PMID:17205134

  13. Chlorine dioxide gas from an aqueous solution: reduction of Salmonella in wounds on tomato fruit and movement to sinks in a treatment chamber.

    PubMed

    Mahovic, Michael; Bartz, Jerry A; Schneider, Keith R; Tenney, Joel D

    2009-05-01

    Chlorine dioxide (ClO2) off-gassed from an aqueous solution and reacted incrementally with potassium iodide solutions (sinks). After 30 min, 45% of the initial dose was detected as chlorite ion in the sink, whereas 35% of the initial dose was still in the source. Aqueous solutions of ClO2 can be used as a source of ClO2 gas in various laboratory experiments involving treatment of fruits or vegetables. Movement from source to sink is continuous, which precludes the development of large headspace concentrations and the need for a tight chamber seal. When the source solution has dissipated, the chamber can be opened safely as there is little free ClO2 remaining in the headspace. In tests with whole, wound-inoculated tomato fruit, at both green and pink stages of ripeness, the control of Salmonella enterica serotype Typhimurium in wounds varied with the weight of gas used. The number of viable cells of Typhimurium recovered was reduced by > 5 log units when > or = 0.5 mg of ClO2 was applied to three pieces of fruit during a 2-h treatment.

  14. Iridium-Coated Rhenium Combustion Chamber

    NASA Technical Reports Server (NTRS)

    Schneider, Steven J.; Tuffias, Robert H.; Rosenberg, Sanders D.

    1994-01-01

    Iridium-coated rhenium combustion chamber withstands operating temperatures up to 2,200 degrees C. Chamber designed to replace older silicide-coated combustion chamber in small rocket engine. Modified versions of newer chamber could be designed for use on Earth in gas turbines, ramjets, and scramjets.

  15. Iridium-Coated Rhenium Combustion Chamber

    NASA Technical Reports Server (NTRS)

    Schneider, Steven J.; Tuffias, Robert H.; Rosenberg, Sanders D.

    1994-01-01

    Iridium-coated rhenium combustion chamber withstands operating temperatures up to 2,200 degrees C. Chamber designed to replace older silicide-coated combustion chamber in small rocket engine. Modified versions of newer chamber could be designed for use on Earth in gas turbines, ramjets, and scramjets.

  16. The dynamic chamber method: trace gas exchange fluxes (NO, NO2, O3) between plants and the atmosphere in the laboratory and in the field

    NASA Astrophysics Data System (ADS)

    Breuninger, C.; Oswald, R.; Kesselmeier, J.; Meixner, F. X.

    2011-08-01

    We describe a dynamic chamber system to determine reactive trace gas exchange fluxes between plants and the atmosphere under laboratory and, with small modifications, also under field conditions. The system allows measurements of the flux density of the reactive NO-NO2-O3 triad and additionally of the non-reactive trace gases CO2 and H2O. The chambers are made of transparent and chemically inert wall material and do not disturb plant physiology. For NO2 detection we used a highly NO2 specific blue light converter coupled to chemiluminescence detection on the photolysis product, NO. Exchange flux densities derived from dynamic chamber measurements are based on very small concentration differences of NO2 (NO, O3) between inlet and outlet of the chamber. High accuracy and precision measurements are therefore required, and high instrument sensitivity (limit of detection) and the statistical significance of concentration differences are important for the determination of corresponding exchange flux densities, compensation point concentrations, and deposition velocities. The determination of NO2 concentrations at sub-ppb levels (<1 ppb) requires a highly sensitive NO/NO2 analyzer with a lower detection limit (3σ-definition) of 0.3 ppb or better. Deposition velocities and compensation point concentrations were determined by bi-variate weighted linear least-squares fitting regression analysis of the trace gas concentrations, measured at the inlet and outlet of the chamber. Performances of the dynamic chamber system and data analysis are demonstrated by studies of Picea abies L. (Norway Spruce) under field and laboratory conditions. Our laboratory data clearly show that highly significant compensation point concentrations can only be detected if the NO2 concentration differences were statistically significant and the data were rigorously controlled for this criterion. The results of field experiments demonstrate the need to consider photo-chemical reactions of NO, NO2, and

  17. TH-E-BRE-09: TrueBeam Monte Carlo Absolute Dose Calculations Using Monitor Chamber Backscatter Simulations and Linac-Logged Target Current

    SciTech Connect

    A, Popescu I; Lobo, J; Sawkey, D; Svatos, M

    2014-06-15

    Purpose: To simulate and measure radiation backscattered into the monitor chamber of a TrueBeam linac; establish a rigorous framework for absolute dose calculations for TrueBeam Monte Carlo (MC) simulations through a novel approach, taking into account the backscattered radiation and the actual machine output during beam delivery; improve agreement between measured and simulated relative output factors. Methods: The ‘monitor backscatter factor’ is an essential ingredient of a well-established MC absolute dose formalism (the MC equivalent of the TG-51 protocol). This quantity was determined for the 6 MV, 6X FFF, and 10X FFF beams by two independent Methods: (1) MC simulations in the monitor chamber of the TrueBeam linac; (2) linac-generated beam record data for target current, logged for each beam delivery. Upper head MC simulations used a freelyavailable manufacturer-provided interface to a cloud-based platform, allowing use of the same head model as that used to generate the publicly-available TrueBeam phase spaces, without revealing the upper head design. The MC absolute dose formalism was expanded to allow direct use of target current data. Results: The relation between backscatter, number of electrons incident on the target for one monitor unit, and MC absolute dose was analyzed for open fields, as well as a jaw-tracking VMAT plan. The agreement between the two methods was better than 0.15%. It was demonstrated that the agreement between measured and simulated relative output factors improves across all field sizes when backscatter is taken into account. Conclusion: For the first time, simulated monitor chamber dose and measured target current for an actual TrueBeam linac were incorporated in the MC absolute dose formalism. In conjunction with the use of MC inputs generated from post-delivery trajectory-log files, the present method allows accurate MC dose calculations, without resorting to any of the simplifying assumptions previously made in the True

  18. Landfill gas and leachate monitoring: Helena, Montana - a technical assistance panels program report. Final report

    SciTech Connect

    Baker, R.; Jewett, M.; Jubenville, D.; Kuntz, D.; Lokey, B.

    1981-07-01

    Leachate contamination of ground water and methane gas production are potential problems associated with solid wastes deposited in landfills. Expanding urban areas may utilize former sites for residential building sites, schools, and parks. This report presents an example of a method which can be used to design a permanent methane gas and leachate monitoring program from a relatively inexpensive preliminary investigation. The monitoring program was conducted on a landfill located within the city limits of Helena, Montana in 1980. A barhole punch survey was conducted to delineate areas of methane gas concentrations and to guide placement of wells. Seven monitoring wells were drilled, logged, and samples were collected. An MSA Model 53 Gascope was used to measure the percent of volume of gas in air and the lower explosive limit of the gas. Water samples were analyzed in a laboratory under selected parameters. Preliminary findings indicated that only a moderate amount of methane gas is being generated and migration of the gas appeared to be minimal. Leachate from the landfill did not appear to have contaminated the ground water. The report recommends that a long term water quality and methane gas monitoring program be instituted and estimates costs of such a program.

  19. Strategies for Detecting Hidden Geothermal Systems by Near-Surface Gas Monitoring

    SciTech Connect

    Lewicki, Jennifer L.; Oldenburg, Curtis M.

    2004-12-15

    -surface environment include (1) the infrared gas analyzer (IRGA) for measurement of concentrations at point locations, (2) the accumulation chamber (AC) method for measuring soil CO2 fluxes at point locations, (3) the eddy covariance (EC) method for measuring net CO2 flux over a given area, (4) hyperspectral imaging of vegetative stress resulting from elevated CO2 concentrations, and (5) light detection and ranging (LIDAR) that can measure CO2 concentrations over an integrated path. Technologies currently in developmental stages that have the potential to be used for CO2 monitoring include tunable lasers for long distance integrated concentration measurements and micro-electronic mechanical systems (MEMS) that can make widespread point measurements. To address the challenge of detecting potentially small-magnitude geothermal CO2 emissions within the natural background variability of CO2, we propose an approach that integrates available detection and monitoring methodologies with statistical analysis and modeling strategies. Within the area targeted for geothermal exploration, point measurements of soil CO2 fluxes and concentrations using the AC method and a portable IRGA, respectively, and measurements of net surface flux using EC should be made. Also, the natural spatial and temporal variability of surface CO2 fluxes and subsurface CO2 concentrations should be quantified within a background area with similar geologic, climatic, and ecosystem characteristics to the area targeted for geothermal exploration. Statistical analyses of data collected from both areas should be used to guide sampling strategy, discern spatial patterns that may be indicative of geothermal CO2 emissions, and assess the presence (or absence) of geothermal CO2 within the natural background variability with a desired confidence level. Once measured CO2 concentrations and fluxes have been determined to be of anomalous geothermal origin with high confidence, more expensive vertical subsurface gas sampling and

  20. Portable Mass Spectrometer System for in-situ Environmental Gas Monitoring

    NASA Technical Reports Server (NTRS)

    Conejo, E.; Griffin, T. P.; Diaz, J. A.; Arkin, C. R.; Soto, C.; Naylor, G. R.; Curley, C.; Floyd, D.

    2005-01-01

    A system developed by NASA has been used for monitoring air quality around different locations. The system was designed for aircraft applications but has proven to be very useful as a portable gas analyzer. The system has been used to monitor air quality around volcanoes, cities, and the surrounding areas. The transport of the system has been via aircraft, car, and hand carried.

  1. Choosing the right positions for corrosion monitoring on oil and gas pipelines

    SciTech Connect

    Gartland, P.O.

    1998-12-31

    Non-intrusive, electric field based equipment offers the possibility of monitoring pipelines for internal corrosion over the lifetime at selected positions. The paper presents a method for calculating the corrosivity along the pipeline and to find optimum positions for corrosion monitoring. Examples of case studies on pipelines carrying wet and dried gas are presented.

  2. Review of Monitoring Plans for Gas Bubble Disease Signs and Gas Supersaturation Levels on the Columbia and Snake Rivers.

    SciTech Connect

    Fidler, Larry; Elston, Ralph; Colt, John

    1994-07-01

    Montgomery Watson was retained by the Bonneville Power Administration to evaluate the monitoring program for gas bubble disease signs and dissolved gas supersaturation levels on the Columbia and Snake rivers. The results of this evaluation will provide the basis for improving protocols and procedures for future monitoring efforts. Key study team members were Dr. John Colt, Dr. Larry Fidler, and Dr. Ralph Elston. On the week of June 6 through 10, 1994 the study team visited eight monitoring sites (smolt, adult, and resident fish) on the Columbia and Snake rivers. Additional protocol evaluations were conducted at the Willard Field Station (National Biological Survey) and Pacific Northwest Laboratories at Richland (Battelle). On June 13 and 14, 1994, the study team visited the North Pacific Division office of the U.S. Corps of Engineers and the Fish Passage Center to collect additional information and data on the monitoring programs. Considering the speed at which the Gas Bubble Trauma Monitoring Program was implemented this year, the Fish Passage Center and cooperating Federal, State, and Tribal Agencies have been doing an incredible job. Thirty-one specific recommendations are presented in this report and are summarized in Section 14.

  3. Satellite monitoring of trace gas and aerosol emissions during wildfires in Russia

    NASA Astrophysics Data System (ADS)

    Bondur, V. G.

    2016-12-01

    Peculiarities of the formation of carbon gas and fine aerosol emissions into the atmosphere during wildfires are analyzed. A prompt satellite monitoring system and technique for the assessment of burnt areas and volumes of CO2, CO, and PM2.5 emissions from wildfires are described. The results of satellite monitoring of the Russian Federation and some Russian regions for different months over 2010-2014 are given; burnt areas and volumes of carbon gas and aerosol emissions throughout the entire territory are assessed. The peculiarities of seasonal frequencies of wildfires and volumes of hazardous gas and fine aerosol emissions in the regions under study are identified.

  4. Overview of the data analysis and new micro-pattern gas detector development for the Active Target Time Projection Chamber (AT-TPC) project.

    NASA Astrophysics Data System (ADS)

    Ayyad, Yassid; Mittig, Wolfgang; Bazin, Daniel; Cortesi, Marco

    2017-07-01

    The Active Target Time Projection Chamber (AT-TPC) project at the NSCL (National Superconducting Cyclotron Laboratory, Michigan State University) is a novel active target detector tailored for low-energy nuclear reactions in inverse kinematics with radioactive ion beams. The AT-TPC allows for a full three dimensional reconstruction of the reaction and provides high luminosity without degradation of resolution by the thickness of the target. Since all the particles (and also the reaction vertex) are tracked inside the detector, the AT-TPC has full 4π efficiency. The AT-TPC can operate under a magnetic field (2 T) that improves the identification of the particles and the energy resolution through the measurement of the magnetic rigidity. Another important characteristic of the AT-TPC is the high-gain operation achieved by the hybrid thick Gas Electron Multipliers (THGEM)-Micromegas pad plane, that allow operation also in pure elemental gas. These two features make the AT-TPC a unique high resolution spectrometer with full acceptance for nuclear physics reactions. This work presents an overview of the project, focused on the data analysis and the development of new micro-pattern gas detectors.

  5. Sensitivity of Mach-Zehnder interferometer for dissolved gas monitoring

    NASA Astrophysics Data System (ADS)

    Lindecrantz, Susan; Dullo, Firehun T.; Ahluwalia, Balpreet S.; Hellesø, Olav G.

    2014-03-01

    An integrated optical sensor is developed for measuring gas concentration for subsea and atmospheric applications. The optical sensor is based on a waveguide Mach-Zehnder interferometer (MZI). In MZI, the light is spilt into a sensing and a reference arm and after a certain distance the branches are recombined. The sensing branch is covered with a sensitive layer that has high affinity towards a specified gas. The presence of the gas gives a change in the refractive index of the sensing arm, which is translated into a change in the output signal. With a prior calibration, the change in the output signal is correlated to the gas concentration. The waveguide should be single-mode and it is desirable to have high intensity in the evanescent field. By using a high refractive index material and a thin waveguide core, the intensity of the evanescent field can be enhanced. Simulations are performed to obtain waveguide parameters with low losses and high sensitivity. The maximum sensitivity at wavelength 785 nm was obtained for a waveguide of core thickness 150 nm, rib height 5 nm and width 1 m for TM polarization. The first measurements of phase sensitivity of 12456π rad/RIU was obtain by the Hydrogen Chlorine (HCl) measurement. This is comparable to the phase sensitivity of 14268π rad/RIU obtained by the simulation.μ

  6. IONIZATION CHAMBER

    DOEpatents

    Redman, W.C.; Shonka, F.R.

    1958-02-18

    This patent describes a novel ionization chamber which is well suited to measuring the radioactivity of the various portions of a wire as the wire is moved at a uniform speed, in order to produce the neutron flux traverse pattern of a reactor in which the wire was previously exposed to neutron radiation. The ionization chamber of the present invention is characterized by the construction wherein the wire is passed through a tubular, straight electrode and radiation shielding material is disposed along the wire except at an intermediate, narrow area where the second electrode of the chamber is located.

  7. A new online exhaust gas monitoring system in hydrochloric acid regeneration of cold rolling mills.

    PubMed

    Tuo, Long; Zheng, Xiang; Chen, Xiong

    2015-07-07

    Measuring the content of hydrogen chloride (HCl) in exhaust gas used to take time and energy. In this paper, we introduce a new online monitoring system which can output real-time data to the monitoring center. The system samples and cools exhaust gas, and after a series of processing, it will be analyzed by a specific instrument. The core part of this system is remote terminal unit (RTU) which is designed on Cortex-A8 embedded architecture. RTU runs a scaled-down version of Linux which is a good choice of OS for embedded applications. It controls the whole processes, does data acquisition and data analysis, and communicates with monitoring center through Ethernet. In addition, through a software developed for windows, the monitoring process can be remotely controlled. The new system is quite beneficial for steel industry to do environment monitoring.

  8. Environmental Monitoring and the Gas Industry: Program Manager Handbook

    SciTech Connect

    Gregory D. Gillispie

    1997-12-01

    This document has been developed for the nontechnical gas industry manager who has the responsibility for the development of waste or potentially contaminated soil and groundwater data or must make decisions based on such data for the management or remediation of these materials. It explores the pse of common analytical chemistry instrumentation and associated techniques for identification of environmentally hazardous materials. Sufficient detail is given to familiarize the nontechnical reader with the principles behind the operation of each technique. The scope and realm of the techniques and their constituent variations are portrayed through a discussion of crucial details and, where appropriate, the depiction of real-life data. It is the author's intention to provide an easily understood handbook for gas industry management. Techniques which determine the presence, composition, and quantification of gas industry wastes are discussed. Greater focus is given to traditional techniques which have been the mainstay of modem analytical benchwork. However, with the continual advancement of instrumental principles and design, several techniques have been included which are likely to receive greater attention in fiture considerations for waste-related detection. Definitions and concepts inherent to a thorough understanding of the principles common to analytical chemistry are discussed. It is also crucial that gas industry managers understand the effects of the various actions which take place before, during, and after the actual sampling step. When a series of sample collection, storage, and transport activities occur, new or inexperienced project managers may overlook or misunderstand the importance of the sequence. Each step has an impact on the final results of the measurement process; errors in judgment or decision making can be costly. Specific techniques and methodologies for the collection, storage, and transport of environmental media samples are not described or

  9. Laboratory Connections--Gas Monitoring Transducers Part III: Combustible Gas Sensors.

    ERIC Educational Resources Information Center

    Powers, Michael H.; Dahman, Doug

    1989-01-01

    Describes an interface that uses semiconductor metal oxides to detect low gas concentrations. Notes the detector has long life, high stability, good reproducibility, low cost, and is able to convert the gas concentration to an electrical signal with a simple circuit. Theory, schematic, and applications are provided. (MVL)

  10. An in situ method for real-time monitoring of soil gas diffusivity

    NASA Astrophysics Data System (ADS)

    Laemmel, Thomas; Maier, Martin; Schack-Kirchner, Helmer; Lang, Friederike

    2016-04-01

    Soil aeration is an important factor for the biogeochemistry of soils. Generally, gas exchange between soil and atmosphere is assumed to be governed by molecular diffusion and by this way fluxes can be calculated using by Fick's Law. The soil gas diffusion coefficient DS represents the proportional factor between the gas flux and the gas concentration gradient in the soil and reflects the ability of the soil to "transport passively" gas through the soil. One common way to determine DS is taking core samples in the field and measuring DS in the lab. Unfortunately this method is destructive and laborious and it can only reflect a small fraction of the whole soil. As a consequence, uncertainty about the resulting effective diffusivity on the profile scale, i.e. the real aeration status remains. We developed a method to measure and monitor DS in situ. The set-up consists of a custom made gas sampling device, the continuous injection of an inert tracer gas and inverse gas transport modelling in the soil. The gas sampling device has seven sampling depths (from 0 to -43 cm of depth) and can be easily installed into vertical holes drilled by an auger, which allows for fast installation of the system. Helium (He) as inert tracer gas was injected continuously at the lower end of the device. The resulting steady state distribution of He was used to deduce the DS depth distribution of the soil. For Finite Element Modeling of the gas-sampling-device/soil system the program COMSOL was used. We tested our new method both in the lab and in a field study and compared the results with a reference lab method using soil cores. DS profiles obtained by our in-situ method were consistent with DS profiles determined based on soil core analyses. Soil gas profiles could be measured with a temporal resolution of 30 minutes. During the field study, there was an important rain event and we could monitor the decrease in soil gas diffusivity in the top soil due to water infiltration. The effect

  11. Assessment and Design of Water Quality Monitoring Networks with respect to Shale Gas Activities in Pennsylvania

    NASA Astrophysics Data System (ADS)

    Arjmand, S.; Abad, J. D.; Brantley, S. L.

    2013-12-01

    Over the past few years, hydraulic fracturing and horizontal drilling techniques have been extensively used to extract shale gas from the Marcellus Shale. Likewise, several environmental violations that have been repeatedly reported in drilling sites have created greater awareness on potentially adverse environmental impacts of shale gas. Long-term monitoring in the Marcellus Shale is the key to maintain and improve the quality of water supplies in future. Currently, the absence of an efficient water quality monitoring network prevents the detection and source identification of contaminants associated with shale gas activities. Evaluation and re-design of monitoring networks from time to time is a major step towards efficient water resources planning and management. In this study, we assessed the performance of the current water quality monitoring network with respect to the shale gas development in Pennsylvania. For better evaluation, the Oil and Gas Compliance Report by the Pennsylvania Department of Environmental Protection between January 2005 and May 2013 was compiled. Using statistical and GIS methods each violation item was examined against the number and location of sensors in the current monitoring network. The results helped identify the adequacy of the number of sensors to detect the potential contamination. Moreover, to improve the performance and to lower the long-term monitoring costs, we re-designed the network using optimization methods. This optimal system maximizes the understanding of the aquifer condition and investigates the shale gas industry impacts on shallow aquifers, and it is applicable to other watersheds with shale oil and gas drilling activities.

  12. Design, construction and performance tests of a prototype micromegas chamber with two readout planes in a common gas volume

    NASA Astrophysics Data System (ADS)

    Brickwedde, Bernard; Düdder, Andreas; Schott, Matthias; Yildirim, Eda

    2017-08-01

    In this paper, the design and the performance of a prototype detector based on MicroMegas technology with two detection planes in a common gas volume is discussed. The detector is suited for the forward region of LHC detectors, addressing the high-rate environment and limited available space. Each detection plane has an active area of 9 × 9cm2 with a two-dimensional strip readout and is separated by a common gas region with a height of 14 mm . A micro-mesh, working as a cathode, is placed in the middle of the common gas volume separating it into two individual cells. This setup allows for an angle reconstruction of incoming particles with a precision of ∼ 2 mrad. Since this design reduces the impact of multiple scattering effects by the reduced material budget, possible applications for low energy beam experiments can be envisioned. The performance of the prototype detector has been tested with a 4 . 4 GeV electron beam, provided by the test beam facility at DESY.

  13. The future of gas turbine compliance monitoring: The integration of PEMS and CEMS for regulatory compliance

    SciTech Connect

    Macak, J.J. III

    1999-07-01

    When the New Source Performance Standards (NSPS) for Stationary Gas Turbines were first promulgated in 1979 (40 CFR 60, Subpart GG), continuous compliance monitoring for gas turbines was simply a parametric monitoring approach where a unit was tested at four load conditions. For those units where water or steam injection was used for NO{sub x} control, testing consisted of establishing a water (or steam injection) versus fuel flow curve to achieve permitted NO{sub x} emission levels across the load range. Since 1979, the growth in gas turbine popularity has encouraged the development of Predictive Emissions Monitoring Systems (PEMS) where gas turbine operating parameters and ambient conditions are fed into a prediction algorithm to predict, rather than monitor, emissions. However, permitting requirements and technological advances now have gas turbines emitting NO{sub x} in the single digits while the overall combined-cycle thermal efficiency has improved dramatically. The combination of supplemental duct-firing in heat recovery steam generators, pollution prevention technology, post-combustion emission controls, and EPA Continuous Emissions Monitoring System (CEMS) regulations for the power industry, resulted in a shift towards CEMS due to the complexity of the overall process. Yet, CEMS are often considered to be a maintenance nightmare with significant amounts of downtime. CEMS and PEMS have their own advantages and disadvantages. Thus evolved the need to find the optimum balance between CEMS and PEMS for gas turbine projects. To justify the cost of both PEMS and CEMS in the same installation, there must be an economic incentive to do so. This paper presents the application of a PEMS/CEMS monitoring system that integrates both PEMS and CEMS in order to meet, and exceed, all emissions monitoring requirements.

  14. [Concentration calibration method of ambient trace-gas monitoring with tunable diode laser absorption spectroscopy].

    PubMed

    Kan, Rui-feng; Liu, Wen-qing; Zhang, Yu-jun; Liu, Jian-guo; Wang, Min; Gao, Shan-hu; Chen, Jun

    2006-03-01

    Tunable diode laser absorption spectroscopy (TDLAS) is a new method to detect trace-gas qualitatively or quantificationally based on the scan characteristic of the diode laser used to obtain the absorption spectroscopy in the characteristic absorption region It needs to be combined with a long absorption path in the ambient trace-gas measurements. TDLAS is a new trace gas detective method developed with the combination of a tunable diode laser source and a long absorption path; it has significant advantages not only in the sensitivity but also in rapidity of response. It has been widely used in many atmospheric trace-gases detection, ground trace-gas detection and, gas leakage detection. On-line calibrating is necessary to most trace gas monitor, and in the present paper the authors introduced a simple and accurate method, analyzed it in the theory, and proved it's feasibility in the experiment.

  15. Method For Enhanced Gas Monitoring In High Density Flow Streams

    DOEpatents

    Von Drasek, William A.; Mulderink, Kenneth A.; Marin, Ovidiu

    2005-09-13

    A method for conducting laser absorption measurements in high temperature process streams having high levels of particulate matter is disclosed. An impinger is positioned substantially parallel to a laser beam propagation path and at upstream position relative to the laser beam. Beam shielding pipes shield the beam from the surrounding environment. Measurement is conducted only in the gap between the two shielding pipes where the beam propagates through the process gas. The impinger facilitates reduced particle presence in the measurement beam, resulting in improved SNR (signal-to-noise) and improved sensitivity and dynamic range of the measurement.

  16. FePO4 based single chamber air-cathode microbial fuel cell for online monitoring levofloxacin.

    PubMed

    Zeng, Libin; Li, Xinyong; Shi, Yueran; Qi, Yefei; Huang, Daqiong; Tadé, Moses; Wang, Shaobin; Liu, Shaomin

    2017-05-15

    A bio-electrochemical strategy was developed for constructing a simple and sensitive levofloxacin (LEV) sensor based on a single chamber microbial fuel cell (SC-MFC) using FePO4 nanoparticles (NPs) as the cathode catalyst instead of traditional Pt/C. In this assembled sensor device, FePO4 NPs dramatically promoted the electrooxidation of oxygen on the cathode, which helps to accelerate the voltage output from SC-MFC and can provide a powerful guarantee for LEV detection. Scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transform infrared (FTIR) and X-ray photoelectron spectroscopy (XPS) were used to fully characterize the FePO4 NPs. Under the optimized COD condition (3mM), the LEV with a concentration range of 0.1-1000µg/L could be detected successfully, and exhibited the excellent linear interval in the concentration range of 0.1-100µg/L. During this range of concentrations of LEV, a temporary effect on the anode of exoelectrogenic bacterial in less than 10min could occur, and then came back to the normal. It exhibited a long-term stability, maintaining the stable electricity production for 14 months of continuous running. Besides, the detection mechanism was investigated by quantum chemical calculation using density functional theory (DFT).

  17. Gas-particle partitioning and hydrolysis of organic nitrates formed from the oxidation of α-pinene in environmental chamber experiments

    NASA Astrophysics Data System (ADS)

    Bean, Jeffrey K.; Hildebrandt Ruiz, Lea

    2016-02-01

    Gas-particle partitioning and hydrolysis of organic nitrates (ON) influences their role as sinks and sources of NOx and their effects on the formation of tropospheric ozone and organic aerosol (OA). In this work, organic nitrates were formed from the photo-oxidation of α-pinene in environmental chamber experiments under different conditions. Particle-phase ON hydrolysis rates, consistent with observed ON decay, exhibited a nonlinear dependence on relative humidity (RH): an ON decay rate of 2 day-1 was observed when the RH ranged between 20 and 60 %, and no significant ON decay was observed at RH lower than 20 %. In experiments when the highest observed RH exceeded the deliquescence RH of the ammonium sulfate seed aerosol, the particle-phase ON decay rate was as high as 7 day-1 and more variable. The ON gas-particle partitioning was dependent on total OA concentration and temperature, consistent with absorptive partitioning theory. In a volatility basis set, the ON partitioning was consistent with mass fractions of [0 0.11 0.03 0.86] at saturation mass concentrations (C*) of [1 10 100 1000] µg m-3.

  18. Characterization of Wall Loss in an Indoor Smog Chamber

    NASA Astrophysics Data System (ADS)

    Dowdell, T. M.; Smith, D. M.; Fiddler, M. N.; Sexton, K.; Bililign, S.

    2016-12-01

    Indoor smog chambers are customarily used to produce a controlled atmosphere accommodating distinctive particles. A complicating aspect of interpreting data for an experiment that incorporates the use of an indoor smog chamber is determining the wall loss of the particles and gases that make up the controlled atmosphere. To characterize the relative wall losses of different components of the test mixtures within the indoor smog chamber, experiments looking at the concentration-time series of soot and relevant gases will be performed. NOx and ozone are commonly used as these gases because they are the main gas components found in the atmosphere. The NOx and ozone will be injected into the 9.01 m3, or 9,010 L, FEP Teflon-lined indoor smog chamber individually with room lights turned off to minimize chemical reactions. A non-reactive gas, benzene, will also be injected into the chamber as a trace gas. These gases are monitored using a Gas Chromatograph, Ozone Analyzer, and NOx Analyzer. NOx or ozone should show a small-scale decay in the concentration-time series graph, indicating that there is minimal wall loss. If there is a measurable difference in decay compared to the concentration-time series graph of the benzene, then the difference is the wall loss for these gases. Wall loss decays are affected by temperature and relative humidity, which will measured. Evaluating the wall loss as it pertains to various soot particles will be the end-goal. Some concentration decay is going to occur due to dilution, which can be estimated by summing the sampling flow rates and considering the chamber volume. Benzene concentration decays larger than predicted by dilution indicates that the chamber leaks which would need to be corrected. It is important to characterize wall losses so that it can be properly accounted for in any future experiments.The authors acknowledge the support from the National Science Foundation through Grant Number NSF-AGS-1555479

  19. Monitoring of nitropolycyclic aromatic hydrocarbons in food using gas chromatography.

    PubMed

    Schlemitz, S; Pfannhauser, W

    1996-07-01

    Nitrated polycyclic aromatic hydrocarbons (nitro-PAHs) were determined in different kinds of food. The investigation of food matrices necessitates the development of appropriate analytical procedures for sensitive monitoring and determination of these compounds. The analysis of the nitro-PAHs was carried out by GC/MSD, GC plus mass spectrometry, and GC/NPD (nitrogen-phosphorus detection) GC plus nitrogen-phosphorus detection. Seven nitro-PAHs were positively identified and quantified in vegetables, smoked and grilled foods, oil, tea, coffee and spices.

  20. Comparative study of gas-analyzing systems designed for continuous monitoring of TPP emissions

    NASA Astrophysics Data System (ADS)

    Kondrat'eva, O. E.; Roslyakov, P. V.

    2017-06-01

    Determining the composition of combustion products is important in terms of both control of emissions into the atmosphere from thermal power plants and optimization of fuel combustion processes in electric power plants. For this purpose, the concentration of oxygen, carbon monoxide, nitrogen, and sulfur oxides in flue gases is monitored; in case of solid fuel combustion, fly ash concentration is monitored as well. According to the new nature conservation law in Russia, all large TPPs shall be equipped with continuous emission monitoring and measurement systems (CEMMS) into the atmosphere. In order to ensure the continuous monitoring of pollutant emissions, direct round-the-clock measurements are conducted with the use of either domestically produced or imported gas analyzers and analysis systems, the operation of which is based on various physicochemical methods and which can be generally used when introducing CEMMS. Depending on the type and purposes of measurement, various kinds of instruments having different features may be used. This article represents a comparative study of gas-analysis systems for measuring the content of polluting substances in exhaust gases based on various physical and physicochemical analysis methods. It lists basic characteristics of the methods commonly applied in the area of gas analysis. It is proven that, considering the necessity of the long-term, continuous operation of gas analyzers for monitoring and measurement of pollutant emissions into the atmosphere, as well as the requirements for reliability and independence from aggressive components and temperature of the gas flow, it is preferable to use optical gas analyzers for the aforementioned purposes. In order to reduce the costs of equipment comprising a CEMMS at a TPP and optimize the combustion processes, electrochemical and thermomagnetic gas analyzers may also be used.

  1. Electrochemical amperometric gas sensors for environmental monitoring and control

    NASA Technical Reports Server (NTRS)

    Venkatasetty, H. V.

    1990-01-01

    Theoretical considerations and experimental results regarding a unique class of vapor sensors are presented, and the sensors are compared to semiconductor-based sensors. The electrochemical sensors are based on nonaquaeous electrolytes, and gas-detection selectivity achieved by applying a known potential to the sensing electrode using a reference electrode and a counter electrode. Results are given regarding the detection of oxygen and carbon dioxide using one cell, the detection of 3-percent carbon dioxide in nitrogen, and the detection of carbon dioxide in air at percentages ranging from 3 to 6. The sensors are found to be effective in the detection of toxic chemical species including CO, NO2, and formaldehyde; the sensors are further found to require minimal power, operate over long periods of time, and function over a wide temperature range.

  2. Monitoring temperature for gas turbine blade: correction of reflection model

    NASA Astrophysics Data System (ADS)

    Gao, Shan; Wang, Lixin; Feng, Chi; Xiao, Yihan; Daniel, Ketui

    2015-06-01

    For a gas turbine blade working in a narrow space, the accuracy of blade temperature measurements is greatly impacted by environmental irradiation. A reflection model is established by using discrete irregular surfaces to calculate the angle factor between the blade surface and the hot adjacent parts. The model is based on the rotational angles and positions of the blades, and can correct for measurement error caused by background radiation when the blade is located at different rotational positions. This method reduces the impact of reflected radiation on the basis of the turbine's known geometry and the physical properties of the material. The experimental results show that when the blade temperature is 911.2±5 K and the vane temperature ranges from 1011.3 to 1065.8 K, the error decreases from 4.21 to 0.75%.

  3. Electrochemical amperometric gas sensors for environmental monitoring and control

    NASA Technical Reports Server (NTRS)

    Venkatasetty, H. V.

    1990-01-01

    Theoretical considerations and experimental results regarding a unique class of vapor sensors are presented, and the sensors are compared to semiconductor-based sensors. The electrochemical sensors are based on nonaquaeous electrolytes, and gas-detection selectivity achieved by applying a known potential to the sensing electrode using a reference electrode and a counter electrode. Results are given regarding the detection of oxygen and carbon dioxide using one cell, the detection of 3-percent carbon dioxide in nitrogen, and the detection of carbon dioxide in air at percentages ranging from 3 to 6. The sensors are found to be effective in the detection of toxic chemical species including CO, NO2, and formaldehyde; the sensors are further found to require minimal power, operate over long periods of time, and function over a wide temperature range.

  4. The CMS RPC gas gain monitoring system: An overview and preliminary results

    NASA Astrophysics Data System (ADS)

    Benussi, L.; Bianco, S.; Colafranceschi, S.; Colonna, D.; Daniello, L.; Fabbri, F. L.; Giardoni, M.; Ortenzi, B.; Paolozzi, A.; Passamonti, L.; Pierluigi, D.; Ponzio, B.; Pucci, C.; Russo, A.; Roselli, G.; Colaleo, A.; Loddo, F.; Maggi, M.; Ranieri, A.; Abbrescia, M.; Iaselli, G.; Marangelli, B.; Natali, S.; Nuzzo, S.; Pugliese, G.; Romano, F.; Trentadue, R.; Tupputi, S.; Guida, R.; Polese, G.; Cavallo, N.; Cimmino, A.; Lomidze, D.; Noli, P.; Paolucci, P.; Piccolo, D.; Sciacca, C.; Baesso, P.; Necchi, M.; Pagano, D.; Ratti, S. P.; Vitulo, P.; Viviani, C.

    2009-05-01

    The status of the Compact Solenoid Spectrometer (CMS) Resistive Plate Counter (RPC) Gas Gain Monitoring (GGM) system developed at the Frascati Laboratory of INFN (Istituto Nazionale di Fisica Nucleare) is reported. The GGM system is a cosmic ray telescope based on small RPC detectors operated with the same gas mixture used by the CMS RPC system. The GGM gain and efficiency are continuously monitored on-line, thus providing a fast and accurate determination of any shift in working point conditions. The construction details and the first result of GGM commissioning are described.

  5. Design and first operation of a supersonic gas jet based beam profile monitor

    NASA Astrophysics Data System (ADS)

    Tzoganis, Vasilis; Zhang, Hao D.; Jeff, Adam; Welsch, Carsten P.

    2017-06-01

    Noninterceptive beam profile monitors are of great importance for many particle accelerators worldwide. Extra challenges are posed by high energy, high intensity machines and low energy low intensity accelerators. For these applications, existing diagnostics are no longer suitable due to the high power of the beam or the very low intensity. In addition, many other accelerators, from medical to industrial will benefit from a noninvasive, real time beam profile monitor. In this paper we present a new beam profile monitor with a novel design for the nozzle and skimmer configuration to generate a supersonic gas jet meeting ultrahigh vacuum conditions and we describe the first results for such a beam profile monitor at the Cockcroft Institute. This monitor is able to measure two-dimensional profiles of the particle beam while causing negligible disturbance to the beam or to the accelerator vacuum. The ultimate goal for this diagnostic is to provide a versatile and universal beam profile monitor suitable for measuring any beams.

  6. Diffuse gas emissions at the Ukinrek Maars, Alaska: Implications for magmatic degassing and volcanic monitoring

    USGS Publications Warehouse

    Evans, William C.; Bergfeld, D.; McGimsey, R.G.; Hunt, A.G.

    2009-01-01

    Diffuse CO2 efflux near the Ukinrek Maars, two small volcanic craters that formed in 1977 in a remote part of the Alaska Peninsula, was investigated using accumulation chamber measurements. High CO2 efflux, in many places exceeding 1000 g m-2 d-1, was found in conspicuous zones of plant damage or kill that cover 30,000-50,000 m2 in area. Total diffuse CO2 emission was estimated at 21-44 t d-1. Gas vents 3-km away at The Gas Rocks produce 0.5 t d-1 of CO2 that probably derives from the Ukinrek Maars basalt based on similar ??13C values (???-6???), 3He/4He ratios (5.9-7.2 RA), and CO2/3He ratios (1-2 ?? 109) in the two areas. A lower 3He/4He ratio (2.7 RA) and much higher CO2/3He ratio (9 ?? 1010) in gas from the nearest arc-front volcanic center (Mount Peulik/Ugashik) provide a useful comparison. The large diffuse CO2 emission at Ukinrek has important implications for magmatic degassing, subsurface gas transport, and local toxicity hazards. Gas-water-rock interactions play a major role in the location, magnitude and chemistry of the emissions.

  7. Automated Electrostatics Environmental Chamber

    NASA Technical Reports Server (NTRS)

    Calle, Carlos; Lewis, Dean C.; Buchanan, Randy K.; Buchanan, Aubri

    2005-01-01

    The Mars Electrostatics Chamber (MEC) is an environmental chamber designed primarily to create atmospheric conditions like those at the surface of Mars to support experiments on electrostatic effects in the Martian environment. The chamber is equipped with a vacuum system, a cryogenic cooling system, an atmospheric-gas replenishing and analysis system, and a computerized control system that can be programmed by the user and that provides both automation and options for manual control. The control system can be set to maintain steady Mars-like conditions or to impose temperature and pressure variations of a Mars diurnal cycle at any given season and latitude. In addition, the MEC can be used in other areas of research because it can create steady or varying atmospheric conditions anywhere within the wide temperature, pressure, and composition ranges between the extremes of Mars-like and Earth-like conditions.

  8. Estimates of in situ gas hydrate concentration from resistivity monitoring of gas hydrate bearing sediments during temperature equilibration

    USGS Publications Warehouse

    Riedel, M.; Long, P.E.; Collett, T.S.

    2006-01-01

    As part of Ocean Drilling Program Leg 204 at southern Hydrate Ridge off Oregon we have monitored changes in sediment electrical resistivity during controlled gas hydrate dissociation experiments. Two cores were used, each filled with gas hydrate bearing sediments (predominantly mud/silty mud). One core was from Site 1249 (1249F-9H3), 42.1 m below seafloor (mbsf) and the other from Site 1248 (1248C-4X1), 28.8 mbsf. At Site 1247, a third experiment was conducted on a core without gas hydrate (1247B-2H1, 3.6 mbsf). First, the cores were imaged using an infra-red (IR) camera upon recovery to map the gas hydrate occurrence through dissociation cooling. Over a period of several hours, successive runs on the multi-sensor track (includes sensors for P-wave velocity, resistivity, magnetic susceptibility and gamma-ray density) were carried out complemented by X-ray imaging on core 1249F-9H3. After complete equilibration to room temperature (17-18??C) and complete gas hydrate dissociation, the final measurement of electrical resistivity was used to calculate pore-water resistivity and salinities. The calculated pore-water freshening after dissociation is equivalent to a gas hydrate concentration in situ of 35-70% along core 1249F-9H3 and 20-35% for core 1248C-4X1 assuming seawater salinity of in situ pore fluid. Detailed analysis of the IR scan, X-ray images and split-core photographs showed the hydrate mainly occurred disseminated throughout the core. Additionally, in core 1249F-9H3, a single hydrate filled vein, approximately 10 cm long and dipping at about 65??, was identified. Analyses of the logging-while-drilling (LWD) resistivity data revealed a structural dip of 40-80?? in the interval between 40 and 44 mbsf. We further analyzed all resistivity data measured on the recovered core during Leg 204. Generally poor data quality due to gas cracks allowed analyses to be carried out only at selected intervals at Sites 1244, 1245, 1246, 1247, 1248, 1249, and 1252. With a few

  9. Statistical methods to monitor the West Valley off-gas system

    SciTech Connect

    Eggett, D.L.

    1990-10-01

    The off-gas system for the ceramic melter operated at the West Valley Demonstration Project at West Valley, NY, is monitored during melter operation. A one-at-a-time method of monitoring the parameters of the off-gas system is not statistically sound. Therefore, multivariate statistical methods appropriate for the monitoring of many correlated parameters will be used. Monitoring a large number of parameters increases the probability of a false out-of-control signal. If the parameters being monitored are statistically independent, the control limits can be easily adjusted to obtain the desired probability of a false out-of-control signal. However, a high degree of correlation generally exists among the parameters being monitored in the off-gas system. This makes it very difficult to control the probability of false calls (saying the system is out-of-control when it is in-control or saying the system is in-control when it is actually out-of-control). The interpretation of the individual control charts is difficult in the presence of correlation among the variables. When a high degree of correlation exists, variable reduction techniques can be used to reduce the number of parameters. Principal components have been used as a variable reduction technique. The principal component (PC) scores have desirable statistical properties when the original variables are distributed as multivariate normals. Two statistics derived from the PC scores and used to form multivariate control charts are outlined and their distributional properties reviewed. 2 refs., 2 figs.

  10. A gas filter correlation monitor for CO, CH4, and HCl

    NASA Technical Reports Server (NTRS)

    Sebacher, D. I.

    1977-01-01

    A fast response instrument for monitoring the atmospheric constituents CO, CH4, and HCl, using a modified nondispersive infrared technique, was designed, assembled, and tested. This gas filter correlation method uses a sample of gas to provide a selective filter for radiation absorbed in a gas mixture containing the specified gas. Depending on the spectral line broadening, temperature, and optical depth of the gas selected, exceptionally high spectral resolution may be attained. A description of the single beam rotating cell system and its specific application is presented along with the signal processing circuit. Calibrations of the instrument show that the technique can be used to measure CO, CH4, and HCl concentrations as small as 5 ppm-m. A field version was employed to measure diurnal variations of CO and CH4 and the interfering effects of other atmospheric gases were analyzed.

  11. High-Resolution Gas Metering and Nonintrusive Appliance Load Monitoring System

    NASA Astrophysics Data System (ADS)

    Tewolde, Mahder

    This thesis deals with design and implementation of a high-resolution metering system for residential natural gas meters. Detailed experimental measurements are performed on the meter to characterize and understand its measurement properties. Results from these experiments are used to develop a simple, fast and accurate technique to non-intrusively monitor the gas consumption of individual appliances in homes by resolving small amounts of gas usage. The technique is applied on an existing meter retrofitted with a module that includes a high-resolution encoder to collect gas flow data and a microprocessor to analyze and identify appliance load profiles. This approach provides a number of appealing features including low cost, easy installation and integration with automated meter reading (AMR) systems. The application of this method to residential gas meters currently deployed is also given. This is done by performing a load simulation on realistic gas loads with the aim of identifying the necessary parameters that minimize the cost and complexity of the mechanical encoder module. The primary benefits of the system are efficiency analysis, appliance health monitoring and real-time customer feedback of gas usage. Additional benefits of include the ability to detect very small leaks and theft. This system has the potential for wide scale market adoption.

  12. Novel method for online monitoring of dissolved N2O concentrations through a gas stripping device.

    PubMed

    Mampaey, Kris E; van Dongen, Udo G J M; van Loosdrecht, Mark C M; Volcke, Eveline I P

    2015-01-01

    Nitrous oxide emissions from wastewater treatment plants are currently measured by online gas phase analysis or grab sampling from the liquid phase. In this study, a novel method is presented to monitor the liquid phase N2O concentration for aerated as well as non-aerated conditions/reactors, following variations both in time and in space. The monitoring method consists of a gas stripping device, of which the measurement principle is based on a continuous flow of reactor liquid through a stripping flask and subsequent analysis of the N2O concentration in the stripped gas phase. The method was theoretically and experimentally evaluated for its fit for use in the wastewater treatment context. Besides, the influence of design and operating variables on the performance of the gas stripping device was addressed. This method can easily be integrated with online off-gas measurements and allows to better investigate the origin of the gas emissions from the treatment plant. Liquid phase measurements of N2O are of use in mitigation of these emissions. The method can also be applied to measure other dissolved gasses, such as methane, being another important greenhouse gas.

  13. Isotope Ratio Monitoring Gas Chromatography Mass Spectrometry (IRM-GCMS)

    NASA Technical Reports Server (NTRS)

    Freeman, K. H.; Ricci, S. A.; Studley, A.; Hayes, J. M.

    1989-01-01

    On Earth, the C-13 content of organic compounds is depleted by roughly 13 to 23 permil from atmospheric carbon dioxide. This difference is largely due to isotope effects associated with the fixation of inorganic carbon by photosynthetic organisms. If life once existed on Mars, then it is reasonable to expect to observe a similar fractionation. Although the strongly oxidizing conditions on the surface of Mars make preservation of ancient organic material unlikely, carbon-isotope evidence for the existence of life on Mars may still be preserved. Carbon depleted in C-13 could be preserved either in organic compounds within buried sediments, or in carbonate minerals produced by the oxidation of organic material. A technique is introduced for rapid and precise measurement of the C-13 contents of individual organic compounds. A gas chromatograph is coupled to an isotope-ratio mass spectrometer through a combustion interface, enabling on-line isotopic analysis of isolated compounds. The isotope ratios are determined by integration of ion currents over the course of each chromatographic peak. Software incorporates automatic peak determination, corrections for background, and deconvolution of overlapped peaks. Overall performance of the instrument was evaluated by the analysis of a mixture of high purity n-alkanes of know isotopic composition. Isotopic values measured via IRM-GCMS averaged withing 0.55 permil of their conventionally measured values.

  14. Direct monitoring of wind-induced pressure-pumping on gas transport in soil

    NASA Astrophysics Data System (ADS)

    Laemmel, Thomas; Mohr, Manuel; Schindler, Dirk; Schack-Kirchner, Helmer; Maier, Martin

    2017-04-01

    Gas exchange between soil and atmosphere is important for the biogeochemistry of soils and is commonly assumed to be governed by molecular diffusion. Yet a few previous field studies identified other gas transport processes such as wind-induced pressure-pumping to enhance soil-atmosphere fluxes significantly. However, since these wind-induced non-diffusive gas transport processes in soil often occur intermittently, the quantification of their contribution to soil gas emissions is challenging. To quantify the effects of wind-induced pressure-pumping on soil gas transport, we developed a method for in situ monitoring of soil gas transport. The method includes the use of Helium (He) as a tracer gas which was continuously injected into the soil. The resulting He steady-state concentration profile was monitored. Gas transport parameters of the soil were inversely modelled. We used our method during a field campaign in a well-aerated forest soil over three months. During periods of low wind speed, soil gas transport was modelled assuming diffusion as transport process. During periods of high wind speed, the previously steady diffusive He concentration profile showed temporary concentration decreases in the topsoil, indicating an increase of the effective gas transport rate in the topsoil up to 30%. The enhancement of effective topsoil soil gas diffusivity resulted from wind-induced air pressure fluctuations which are referred to as pressure-pumping. These air pressure fluctuations had frequencies between 0.1 and 0.01 Hz and amplitudes up to 10 Pa and occurred at above-canopy wind speeds greater than 5 m s-1. We could show the importance of the enhancement of the gas transport rate in relation with the wind intensity and corresponding air pressure fluctuations characteristics. We directly detected and quantified the pressure-pumping effect on gas transport in soil in a field study for the first time, and could thus validate and underpin the importance of this non

  15. Application of Condition-Based Monitoring Techniques for Remote Monitoring of a Simulated Gas Centrifuge Enrichment Plant

    SciTech Connect

    Hooper, David A; Henkel, James J; Whitaker, Michael

    2012-01-01

    This paper presents research into the adaptation of monitoring techniques from maintainability and reliability (M&R) engineering for remote unattended monitoring of gas centrifuge enrichment plants (GCEPs) for international safeguards. Two categories of techniques are discussed: the sequential probability ratio test (SPRT) for diagnostic monitoring, and sequential Monte Carlo (SMC or, more commonly, particle filtering ) for prognostic monitoring. Development and testing of the application of condition-based monitoring (CBM) techniques was performed on the Oak Ridge Mock Feed and Withdrawal (F&W) facility as a proof of principle. CBM techniques have been extensively developed for M&R assessment of physical processes, such as manufacturing and power plants. These techniques are normally used to locate and diagnose the effects of mechanical degradation of equipment to aid in planning of maintenance and repair cycles. In a safeguards environment, however, the goal is not to identify mechanical deterioration, but to detect and diagnose (and potentially predict) attempts to circumvent normal, declared facility operations, such as through protracted diversion of enriched material. The CBM techniques are first explained from the traditional perspective of maintenance and reliability engineering. The adaptation of CBM techniques to inspector monitoring is then discussed, focusing on the unique challenges of decision-based effects rather than equipment degradation effects. These techniques are then applied to the Oak Ridge Mock F&W facility a water-based physical simulation of a material feed and withdrawal process used at enrichment plants that is used to develop and test online monitoring techniques for fully information-driven safeguards of GCEPs. Advantages and limitations of the CBM approach to online monitoring are discussed, as well as the potential challenges of adapting CBM concepts to safeguards applications.

  16. Designing optimal greenhouse gas monitoring networks for Australia

    NASA Astrophysics Data System (ADS)

    Ziehn, T.; Law, R. M.; Rayner, P. J.; Roff, G.

    2016-01-01

    Atmospheric transport inversion is commonly used to infer greenhouse gas (GHG) flux estimates from concentration measurements. The optimal location of ground-based observing stations that supply these measurements can be determined by network design. Here, we use a Lagrangian particle dispersion model (LPDM) in reverse mode together with a Bayesian inverse modelling framework to derive optimal GHG observing networks for Australia. This extends the network design for carbon dioxide (CO2) performed by Ziehn et al. (2014) to also minimise the uncertainty on the flux estimates for methane (CH4) and nitrous oxide (N2O), both individually and in a combined network using multiple objectives. Optimal networks are generated by adding up to five new stations to the base network, which is defined as two existing stations, Cape Grim and Gunn Point, in southern and northern Australia respectively. The individual networks for CO2, CH4 and N2O and the combined observing network show large similarities because the flux uncertainties for each GHG are dominated by regions of biologically productive land. There is little penalty, in terms of flux uncertainty reduction, for the combined network compared to individually designed networks. The location of the stations in the combined network is sensitive to variations in the assumed data uncertainty across locations. A simple assessment of economic costs has been included in our network design approach, considering both establishment and maintenance costs. Our results suggest that, while site logistics change the optimal network, there is only a small impact on the flux uncertainty reductions achieved with increasing network size.

  17. Ocean observatory networks monitor gas hydrates systems - Updates from Cascadia

    NASA Astrophysics Data System (ADS)

    Scherwath, M.; Kelley, D. S.; Moran, K.; Philip, B. T.; Roemer, M.; Riedel, M.; Solomon, E. A.; Spence, G.; Heesemann, M.

    2015-12-01

    Seafloor observatories have been installed at the Cascadia margin with a long-term (>20 year) lifespan. These observatories consist of a variety of node locations cabled back to shore for continuous power and communication to instruments via high bandwidth internet access. Ocean Networks Canada (ONC) maintains two hydrate sites at Barkley Canyon and Clayoquot Slope off Vancouver Island, and the Ocean Observatories Initiative (OOI) Cabled Array connects to Hydrate Ridge off the Oregon coast. Together, these installations comprise a diverse suite of different experiments. For example, a seafloor crawler, operated by Jacobs University in Bremen, travels around the Barkley hydrate mounds on a daily basis and carries out a suite of measurements such as determining the rate of change of the benthic community composition. Another example is from several years of hourly sonar data showing gas bubbles rising from the seafloor near the Bullseye Vent with varying intensities, allowing statistically sound correlations with other seafloor parameters such as ground shaking, temperature and pressure variations and currents, where tidal pressure appearing as the main driver. The Southern Hydrate Ridge is now equipped with the world's first long-term seafloor mass spectrometer, co-located with a camera and lights, hydrophone, current meters, pressure sensor, autonomous dissolved oxygen and fluid samplers, and is surrounded by a seismometer array for local seismicity. In the future, long-term data will be continuously captured and made available throughout the year covering the full range of variations of the dynamic hydrate system, and expect additional experiments to be connected to the observatories from the broader research community.

  18. Large-Scale Wireless Temperature Monitoring System for Liquefied Petroleum Gas Storage Tanks

    PubMed Central

    Fan, Guangwen; Shen, Yu; Hao, Xiaowei; Yuan, Zongming; Zhou, Zhi

    2015-01-01

    Temperature distribution is a critical indicator of the health condition for Liquefied Petroleum Gas (LPG) storage tanks. In this paper, we present a large-scale wireless temperature monitoring system to evaluate the safety of LPG storage tanks. The system includes wireless sensors networks, high temperature fiber-optic sensors, and monitoring software. Finally, a case study on real-world LPG storage tanks proves the feasibility of the system. The unique features of wireless transmission, automatic data acquisition and management, local and remote access make the developed system a good alternative for temperature monitoring of LPG storage tanks in practical applications. PMID:26393596

  19. Comparison of photoacoustic radiometry to gas chromatography/mass spectrometry methods for monitoring chlorinated hydrocarbons

    SciTech Connect

    Sollid, J.E.; Trujillo, V.L.; Limback, S.P.; Woloshun, K.A.

    1996-03-01

    A comparison of two methods of gas chromatography mass spectrometry (GCMS) and a nondispersive infrared technique, photoacoustic radiometry (PAR), is presented in the context of field monitoring a disposal site. First is presented an historical account describing the site and early monitoring to provide an overview. The intent and nature of the monitoring program changed when it was proposed to expand the Radiological Waste Site close to the Hazardous Waste Site. Both the sampling methods and analysis techniques were refined in the course of this exercise.

  20. Large-Scale Wireless Temperature Monitoring System for Liquefied Petroleum Gas Storage Tanks.

    PubMed

    Fan, Guangwen; Shen, Yu; Hao, Xiaowei; Yuan, Zongming; Zhou, Zhi

    2015-09-18

    Temperature distribution is a critical indicator of the health condition for Liquefied Petroleum Gas (LPG) storage tanks. In this paper, we present a large-scale wireless temperature monitoring system to evaluate the safety of LPG storage tanks. The system includes wireless sensors networks, high temperature fiber-optic sensors, and monitoring software. Finally, a case study on real-world LPG storage tanks proves the feasibility of the system. The unique features of wireless transmission, automatic data acquisition and management, local and remote access make the developed system a good alternative for temperature monitoring of LPG storage tanks in practical applications.

  1. Thrust chamber life prediction

    NASA Technical Reports Server (NTRS)

    Kasper, H. J.

    1985-01-01

    The reusable life of the Space Shuttle main engine (SSME) is influenced by the cyclic life of the regeneratively liquid cooled main combustion chamber (MCC). During an operational duty cycle the MCC liner is subjected to a large transient thermal gradient that imparts a high thermal cyclic strain to the liner hot gas wall. Life predictions of such chambers have usually been based on low cycle fatigue (LCF) evaluations. Hot-fire testing, however, has shown significant mid-channel wall deformation and thinning during accrued cyclic testing. This phenomenon is termed cyclic creep and appears to be significantly accelerated at elevated temperatures. An analytical method that models the cyclic creep phenomenon and its application to thrust chamber life prediction is presented. The chamber finite element geometry is updated periodically to account for accrued wall thinning and distortion. Failure is based on the tensile instability failure criterion. Cyclic life results for several chamber life enhancing coolant channel designs are compared to the typically used LCF analysis that neglects cyclic creep. The results show that the usable cyclic creep life is approximately 30 to 50% of the commonly used LCF life.

  2. Testing fireproof materials in a combustion chamber

    NASA Astrophysics Data System (ADS)

    Kulhavy, Petr; Martinec, Tomas; Novak, Ondrej; Petru, Michal; Srb, Pavel

    This article deals with a prototype concept, real experiment and numerical simulation of a combustion chamber, designed for testing fire resistance some new insulating composite materials. This concept of a device used for testing various materials, providing possibility of monitoring temperatures during controlled gas combustion. As a fuel for the combustion process propane butane mixture has been used and also several kinds of burners with various conditions of inlet air (forced, free) and fuel flows were tested. The tested samples were layered sandwich materials based on various materials or foams, used as fillers in fire shutters. The temperature distribution was measured by using thermocouples. A simulation of whole concept of experimental chamber has been carried out as the non-premixed combustion process in the commercial final volume sw Pyrosim. The result was to design chamber with a construction suitable, according to the international standards, achieve the required values (temperature in time). Model of the combustion based on a stoichiometric defined mixture of gas and the tested layered samples showed good conformity with experimental results - i.e. thermal distribution inside and heat release rate that has gone through the sample.

  3. Testing fireproof materials in a combustion chamber

    NASA Astrophysics Data System (ADS)

    Kulhavy, Petr; Martinec, Tomas; Novak, Ondrej; Petru, Michal; Srb, Pavel

    2016-11-01

    This article deals with a prototype concept, real experiment and numerical simulation of a combustion chamber, designed for testing fire resistance some new insulating composite materials. This concept of a device used for testing various materials, providing possibility of monitoring temperatures during controlled gas combustion. As a fuel for the combustion process propane butane mixture has been used and also several kinds of burners with various conditions of inlet air (forced, free) and fuel flows were tested. The tested samples were layered sandwich materials based on various materials or foams, used as fillers in fire shutters. The temperature distribution was measured by using thermocouples. A simulation of whole concept of experimental chamber has been carried out as the non-premixed combustion process in the commercial final volume sw Pyrosim. The result was to design chamber with a construction suitable, according to the international standards, achieve the required values (temperature in time). Model of the combustion based on a stoichiometric defined mixture of gas and the tested layered samples showed good conformity with experimental results - i.e. thermal distribution inside and heat release rate that has gone through the sample.

  4. A Three Dimensional Beam Profile Monitor Based on Residual Gas Ionization

    SciTech Connect

    Lewis, T.A.; Shapira, D.

    1998-11-04

    A three-dimensional beam profile monitor based on tracking the ionization of the residual gas molecules in the evacuated beam pipe is described. Tracking in position and time of the ions and electrons produced in the ionization enables simultaneous position sampling in three dimensions. Special features which make it possible to sample very low beam currents were employed.

  5. Limitations of a residual gas ionization beam profile monitor for the SSC Collider

    SciTech Connect

    Meinke, R.; Nexsen, W.; Tsyganov, E.; Zinchenko, A.

    1992-11-01

    A residual gas ionization beam profile monitor for the superconducting Super Collider is considered in detail using the Monte Carlo simulation code. It is shown that a good spatial resolution could be obtained using a combination of strong electrical and magnetic fields.

  6. GREENHOUSE GAS (GHG) MITIGATION AND MONITORING TECHNOLOGY PERFORMANCE: ACTIVITIES OF THE GHG TECHNOLOGY VERIFICATION CENTER

    EPA Science Inventory

    The paper discusses greenhouse gas (GHG) mitigation and monitoring technology performance activities of the GHG Technology Verification Center. The Center is a public/private partnership between Southern Research Institute and the U.S. EPA's Office of Research and Development. It...

  7. GREENHOUSE GAS (GHG) MITIGATION AND MONITORING TECHNOLOGY PERFORMANCE: ACTIVITIES OF THE GHG TECHNOLOGY VERIFICATION CENTER

    EPA Science Inventory

    The paper discusses greenhouse gas (GHG) mitigation and monitoring technology performance activities of the GHG Technology Verification Center. The Center is a public/private partnership between Southern Research Institute and the U.S. EPA's Office of Research and Development. It...

  8. Feasibility of monitoring gas hydrate production with time-lapse VSP

    SciTech Connect

    Kowalsky, M.B.; Nakagawa, S.; Moridis, G.J.

    2009-11-01

    In this work we begin to examine the feasibility of using time-lapse seismic methods-specifically the vertical seismic profiling (VSP) method-for monitoring changes in hydrate accumulations that are predicted to occur during production of natural gas.

  9. Design layout for gas monitoring system II (GMS-2) computer system

    SciTech Connect

    Vo, V.; Philipp, B.L.; Manke, M.P.

    1995-08-02

    This document provides a general overview of the computer systems software that perform the data acquisition and control for the 241-SY-101 Gas Monitoring System II (GMS-2). It outlines the system layout, and contains descriptions of components and the functions they perform. The GMS-2 system was designed and implemented by Los Alamos National Laboratory and supplied to Westinghouse Hanford Company

  10. Multiwire proportional chamber development

    NASA Technical Reports Server (NTRS)

    Doolittle, R. F.; Pollvogt, U.; Eskovitz, A. J.

    1973-01-01

    The development of large area multiwire proportional chambers, to be used as high resolution spatial detectors in cosmic ray experiments is described. A readout system was developed which uses a directly coupled, lumped element delay-line whose characteristics are independent of the MWPC design. A complete analysis of the delay-line and the readout electronic system shows that a spatial resolution of about 0.1 mm can be reached with the MWPC operating in the strictly proportional region. This was confirmed by measurements with a small MWPC and Fe-55 X-rays. A simplified analysis was carried out to estimate the theoretical limit of spatial resolution due to delta-rays, spread of the discharge along the anode wire, and inclined trajectories. To calculate the gas gain of MWPC's of different geometrical configurations a method was developed which is based on the knowledge of the first Townsend coefficient of the chamber gas.

  11. All-in-one: a versatile gas sensor based on fiber enhanced Raman spectroscopy for monitoring postharvest fruit conservation and ripening.

    PubMed

    Jochum, Tobias; Rahal, Leila; Suckert, Renè J; Popp, Jürgen; Frosch, Torsten

    2016-03-21

    In today's fruit conservation rooms the ripening of harvested fruit is delayed by precise management of the interior oxygen (O2) and carbon dioxide (CO2) levels. Ethylene (C2H4), a natural plant hormone, is commonly used to trigger fruit ripening shortly before entering the market. Monitoring of these critical process gases, also of the increasingly favored cooling agent ammonia (NH3), is a crucial task in modern postharvest fruit management. The goal of this work was to develop and characterize a gas sensor setup based on fiber enhanced Raman spectroscopy for fast (time resolution of a few minutes) and non-destructive process gas monitoring throughout the complete postharvest production chain encompassing storage and transport in fruit conservation chambers as well as commercial fruit ripening in industrial ripening rooms. Exploiting a micro-structured hollow-core photonic crystal fiber for analyte gas confinement and sensitivity enhancement, the sensor features simultaneous quantification of O2, CO2, NH3 and C2H4 without cross-sensitivity in just one single measurement. Laboratory measurements of typical fruit conservation gas mixtures showed that the sensor is capable of quantifying O2 and CO2 concentration levels with accuracy of 3% or less with respect to reference concentrations. The sensor detected ammonia concentrations, relevant for chemical alarm purposes. Due to the high spectral resolution of the gas sensor, ethylene could be quantified simultaneously with O2 and CO2 in a multi-component mixture. These results indicate that fiber enhanced Raman sensors have a potential to become universally usable on-site gas sensors for controlled atmosphere applications in postharvest fruit management.

  12. Gas hydrate environmental monitoring program in the Ulleung Basin, East Sea of Korea

    NASA Astrophysics Data System (ADS)

    Ryu, Byong-Jae; Chun, Jong-Hwa; McLean, Scott

    2013-04-01

    As a part of the Korean National Gas Hydrate Program, the Korea Institute of Geoscience and Mineral Resources (KIGAM) has been planned and conducted the environmental monitoring program for the gas hydrate production test in the Ulleung Basin, East Sea of Korea in 2014. This program includes a baseline survey using a KIGAM Seafloor Observation System (KISOS) and R/V TAMHAE II of KIGAM, development of a KIGAM Seafloor Monitoring System (KIMOS), and seafloor monitoring on various potential hazards associated with the dissociated gas from gas hydrates during the production test. The KIGAM also plans to conduct the geophysical survey for determining the change of gas hydrate reservoirs and production-efficiency around the production well before and after the production test. During production test, release of gas dissociated from the gas hydrate to the water column, seafloor deformation, changes in chemical characteristics of bottom water, changes in seafloor turbidity, etc. will be monitored by using the various monitoring instruments. The KIMOS consists of a near-field observation array and a far-field array. The near-field array is constructed with four remote sensor platforms each, and cabled to the primary node. The far-field sensor array will consists of four autonomous instrument pods. A scientific Remotely Operated Vehicle (ROV) will be used to deploy the sensor arrays, and to connect the cables to each field instrument package and a primary node. A ROV will also be tasked to collect the water and/or gas samples, and to identify any gas (bubble) plumes from the seafloor using a high-frequency sector scanning sonar. Power to the near-field instrument packages will be supplied by battery units located on the seafloor near the primary node. Data obtained from the instruments on the near-field array will be logged and downloaded in-situ at the primary node, and transmitted real-time to the support vessel using a ROV. These data will also be transmitted real-time to

  13. Monitoring for methane gas in Carbon and Emery Counties, Utah, 1995-2003

    USGS Publications Warehouse

    Burr, Andrew L.; Stolp, Bernard J.; Johnson, Kevin K.; Hunt, Gilbert L.

    2006-01-01

    The release of methane gas from coal beds creates the potential for it to move into near-surface environments through natural and human-made pathways. To help ensure the safety of communities and determine the potential effects of development of coal-bed resources, methane gas concentrations in soils and ground water in Carbon and Emery Counties, Utah, were monitored from 1995 to 2003. A total of 420 samples were collected, which contained an average methane concentration of 2,740 parts per million by volume (ppmv) and a median concentration of less than 10 ppmv. On the basis of spatial and temporal methane concentration data collected during the monitoring period, there does not appear to be an obvious, widespread, or consistent migration of methane gas to the near-surface environment.

  14. State-of-the-art chamber facility for studying atmospheric aerosol chemistry.

    PubMed

    Cocker, D R; Flagan, R C; Seinfeld, J H

    2001-06-15

    A state-of-the-art chamber facility is described for investigation of atmospheric aerosol chemistry. Dual 28 m3 FEP Teflon film chambers are used to simulate atmospheric conditions in which aerosol formation may occur. This facility provides the flexibility to investigate dark, single oxidant reactions as well as full photochemical simulations. This paper discusses the environmental control implemented as well as the gas-phase and aerosol-phase instrumentation used to monitor atmospheric aerosol formation and growth. Physical processes occurring in the chamber and procedures for estimating secondary organic aerosol formation during reaction are described. Aerosol formation and evolution protocols at varying relative humidity conditions are presented.

  15. Capillary - Discharge Based Hand-Held Detector For Chemical Vapor Monitoring

    DOEpatents

    Duan, Yixiang

    2005-05-31

    A handheld/portable detector for chemical vapor monitoring includes a housing and a discharge chamber that is established therein. The plasma discharge has a relatively small volume, e.g., in the micro-liter range. A first electrode and a second electrode are disposed within the discharge chamber and a discharge gap is established therebetween. A sample gas tube is in fluid communication with the discharge chamber and provides a sample gas to the discharge chamber. Also, a plasma gas tube is in fluid communication with the discharge chamber and provides a plasma gas thereto. Accordingly, the plasma gas can be used to maintain microplasma discharge between the electrodes and the sample gas can be introduced into the microplasma discharge. A spectrometer optically connected to the handheld/portable detector is used to measure the radiation emitted by the sample gas when subjected to the microplasma discharge.

  16. On-site monitoring of biogenic emissions from Eucalyptus dunnii leaves using membrane extraction with sorbent interface combined with a portable gas chromatograph system.

    PubMed

    Liu, Xinyu; Pawliszyn, Richard; Wang, Limei; Pawliszyn, Janusz

    2004-01-01

    Membrane extraction with sorbent interface, combined with a portable gas chromatograph system (MESI-Portable GC) for continuous on-line monitoring of biogenic volatile organic compounds (BVOCs) emissions (from leaves of Eucalytus dunnii in a greenhouse), is presented herein. A sampling chamber was designed to facilitate the extraction and identification of the BVOCs emitted by the Eucalytus dunnii leaves. Preliminary experiments, including; enrichment times, microtrap temperatures, stripping gas flow rates, and desorption temperatures were investigated to optimize experimental parameters. The main components of BVOCs released by the Eucalytus dunnii leaves were identified by comparing the retention times of peaks with those of authentic standard solutions. They were then confirmed with solid phase microextraction coupled with gas chromatography and mass spectrometry (SPME-GC-MS). BVOC emission profiles of [small alpha]-pinene, eucalyptol, and [gamma]-terpinene emitted by intact and damaged Eucalytus dunnii leaves were obtained. The findings suggest that the MESI-Portable GC system is a simple and useful tool for field monitoring changes in plant emissions as a function of time.

  17. Exhaust gas monitoring based on absorption spectroscopy in the process industry

    NASA Astrophysics Data System (ADS)

    Zhang, Shuai; Liu, Wen-qing; Zhang, Yu-jun; Shu, Xiao-wen; Kan, Rui-feng; Cui, Yi-ben; He, Ying; Xu, Zhen-yu; Geng, Hui; Liu, Jian-guo

    2009-07-01

    This non-invasive gas monitor for exhaust gas monitoring must has high reliability and requires little maintenance. Monitor for in-situ measurements using tunable diode laser absorption spectroscopy (TDLAS) in the near infrared, can meet these requirements. TDLAS has evolved over the past decade from a laboratory especially to an accepted, robust and reliable technology for trace gas sensing. With the features of tunability and narrow linewidth of the distributed feedback (DFB) diode laser and by precisely tuning the laser output wavelength to a single isolated absorption line of the gas, TDLAS technique can be utilized to measure gas concentration with high sensitivity. Typical applications for monitoring of H2S, NH3, HC1 and HF are described here together by wavelength modulation spectroscopy with second-harmonic(WMS-2F) detection. This paper will illustrate the problems related to on-line applications, in particular, the overfall effects, automatic light intensity correction, temperature correction, which impacted on absorption coefficient and give details of how effect of automatic correction is necessary. The system mainly includes optics and electronics, optical system mainly composed of fiber, fiber coupler and beam expander, the electron part has been placed in safe analysis room not together with the optical part. Laser merely passes through one-meter-long pipes by the fiber coupling technology, so the system itself has anti-explosion. The results of the system are also presented in the end, the system's response time is only 0.5s, and can be achieved below 1×10-5 the detection limit at the volume fraction, it can entirely replace the traditional methods of detection exhaust gas in the process industry.

  18. Gas Filled RF Resonator Hadron Beam Monitor for Intense Neutrino Beam Experiments

    SciTech Connect

    Yonehara, Katsuya; Abrams, Robert; Dinkel, Holly; Freemire, Ben; Johnson, Rolland; Kazakevich, Grigory; Tollestrup, Alvin; Zwaska, Robert

    2016-06-01

    MW-class beam facilities are being considered all over the world to produce an intense neutrino beam for fundamental particle physics experiments. A radiation-robust beam monitor system is required to diagnose the primary and secondary beam qualities in high-radiation environments. We have proposed a novel gas-filled RF-resonator hadron beam monitor in which charged particles passing through the resonator produce ionized plasma that changes the permittivity of the gas. The sensitivity of the monitor has been evaluated in numerical simulation. A signal manipulation algorithm has been designed. A prototype system will be constructed and tested by using a proton beam at the MuCool Test Area at Fermilab.

  19. Performance of a Micro-Strip Gas Chamber for event wise, high rate thermal neutron detection with accurate 2D position determination

    NASA Astrophysics Data System (ADS)

    Mindur, B.; Alimov, S.; Fiutowski, T.; Schulz, C.; Wilpert, T.

    2014-12-01

    A two-dimensional (2D) position sensitive detector for neutron scattering applications based on low-pressure gas amplification and micro-strip technology was built and tested with an innovative readout electronics and data acquisition system. This detector contains a thin solid neutron converter and was developed for time- and thus wavelength-resolved neutron detection in single-event counting mode, which improves the image contrast in comparison with integrating detectors. The prototype detector of a Micro-Strip Gas Chamber (MSGC) was built with a solid natGd/CsI thermal neutron converter for spatial resolutions of about 100 μm and counting rates up to 107 neutrons/s. For attaining very high spatial resolutions and counting rates via micro-strip readout with centre-of-gravity evaluation of the signal amplitude distributions, a fast, channel-wise, self-triggering ASIC was developed. The front-end chips (MSGCROCs), which are very first signal processing components, are read out into powerful ADC-FPGA boards for on-line data processing and thereafter via Gigabit Ethernet link into the data receiving PC. The workstation PC is controlled by a modular, high performance dedicated software suite. Such a fast and accurate system is crucial for efficient radiography/tomography, diffraction or imaging applications based on high flux thermal neutron beam. In this paper a brief description of the detector concept with its operation principles, readout electronics requirements and design together with the signals processing stages performed in hardware and software are presented. In more detail the neutron test beam conditions and measurement results are reported. The focus of this paper is on the system integration, two dimensional spatial resolution, the time resolution of the readout system and the imaging capabilities of the overall setup. The detection efficiency of the detector prototype is estimated as well.

  20. Quantitative analysis of deuterium in zircaloy using double-pulse laser-induced breakdown spectrometry (LIBS) and helium gas plasma without a sample chamber.

    PubMed

    Suyanto, H; Lie, Z S; Niki, H; Kagawa, K; Fukumoto, K; Rinda, Hedwig; Abdulmadjid, S N; Marpaung, A M; Pardede, M; Suliyanti, M M; Hidayah, A N; Jobiliong, E; Lie, T J; Tjia, M O; Kurniawan, K H

    2012-03-06

    A crucial safety measure to be strictly observed in the operation of heavy-water nuclear power plants is the mandatory regular inspection of the concentration of deuterium penetrated into the zircaloy fuel vessels. The existing standard method requires a tedious, destructive, and costly sample preparation process involving the removal of the remaining fuel in the vessel and melting away part of the zircaloy pipe. An alternative method of orthogonal dual-pulse laser-induced breakdown spectrometry (LIBS) is proposed by employing flowing atmospheric helium gas without the use of a sample chamber. The special setup of ps and ns laser systems, operated for the separate ablation of the sample target and the generation of helium gas plasma, respectively, with properly controlled relative timing, has succeeded in producing the desired sharp D I 656.10 nm emission line with effective suppression of the interfering H I 656.28 nm emission by operating the ps ablation laser at very low output energy of 26 mJ and 1 μs ahead of the helium plasma generation. Under this optimal experimental condition, a linear calibration line is attained with practically zero intercept and a 20 μg/g detection limit for D analysis of zircaloy sample while creating a crater only 10 μm in diameter. Therefore, this method promises its potential application for the practical, in situ, and virtually nondestructive quantitative microarea analysis of D, thereby supporting the more-efficient operation and maintenance of heavy-water nuclear power plants. Furthermore, it will also meet the anticipated needs of future nuclear fusion power plants, as well as other important fields of application in the foreseeable future.

  1. Shale gas impacts on groundwater resources: insights from monitoring a fracking site in Poland

    NASA Astrophysics Data System (ADS)

    Montcoudiol, Nelly; Isherwood, Catherine; Gunning, Andrew; Kelly, Thomas; Younger, Paul

    2017-04-01

    Exploitation of shale gas by hydraulic fracturing (fracking) is highly controversial and concerns have been raised regarding induced risks from this technique. The SHEER project, an EU Horizon 2020-funded project, is looking into developing best practice to understand, prevent and mitigate the potential short- and long-term environmental impacts and risks from shale gas exploration and exploitation. Three major potential impacts were identified: groundwater contamination, air pollution and induced seismicity. This presentation will deal with the hydrogeological aspect. As part of the SHEER project, four monitoring wells were installed at a shale gas exploration site in Northern Poland. They intercept the main drinking water aquifer located in Quaternary sediments. Baseline monitoring was carried out from mid-December 2015 to beginning of June 2016. Fracking operations occurred in two horizontal wells, in two stages, in June and July 2016. The monitoring has continued after fracking was completed, with site visits every 4-6 weeks. Collected data include measurements of groundwater level, conductivity and temperature at 15-minute intervals, frequent sampling for laboratory analyses and field measurements of groundwater physico-chemical parameters. Groundwater samples are analysed for a range of constituents including dissolved gases and isotopes. The presentation will focus on the interpretation of baseline monitoring data. The insights gained into the behaviour of the Quaternary aquifer will allow a greater perspective to be place on the initial project understanding draw from previous studies. Short-term impacts will also be discussed in comparison with the baseline monitoring results. The presentation will conclude with discussion of challenges regarding monitoring of shale gas fracking sites.

  2. Gas system Upgrade for the BaBar IFR Detector at SLAC

    SciTech Connect

    Foulkes, S

    2004-07-29

    A new gas distribution and monitoring system was installed as part of an upgrade of the forward endcap muon detection system (IFR) of the BaBar detector at SLAC. Over 300 gas circuits are controlled and monitored. The return gas flow is monitored by digital bubblers which use photo-gate electronics to count the bubbling rate. The rates are monitored in real time and recorded in a history database allowing studies of flow rate versus chamber performance.

  3. Enabling Technology for Monitoring & Predicting Gas Turbine Health & Performance in IGCC Powerplants

    SciTech Connect

    Kenneth A. Yackly

    2005-12-01

    The ''Enabling & Information Technology To Increase RAM for Advanced Powerplants'' program, by DOE request, was re-directed, de-scoped to two tasks, shortened to a 2-year period of performance, and refocused to develop, validate and accelerate the commercial use of enabling materials technologies and sensors for coal/IGCC powerplants. The new program was re-titled ''Enabling Technology for Monitoring & Predicting Gas Turbine Health & Performance in IGCC Powerplants''. This final report summarizes the work accomplished from March 1, 2003 to March 31, 2004 on the four original tasks, and the work accomplished from April 1, 2004 to July 30, 2005 on the two re-directed tasks. The program Tasks are summarized below: Task 1--IGCC Environmental Impact on high Temperature Materials: The first task was refocused to address IGCC environmental impacts on high temperature materials used in gas turbines. This task screened material performance and quantified the effects of high temperature erosion and corrosion of hot gas path materials in coal/IGCC applications. The materials of interest included those in current service as well as advanced, high-performance alloys and coatings. Task 2--Material In-Service Health Monitoring: The second task was reduced in scope to demonstrate new technologies to determine the inservice health of advanced technology coal/IGCC powerplants. The task focused on two critical sensing needs for advanced coal/IGCC gas turbines: (1) Fuel Quality Sensor to rapidly determine the fuel heating value for more precise control of the gas turbine, and detection of fuel impurities that could lead to rapid component degradation. (2) Infra-Red Pyrometer to continuously measure the temperature of gas turbine buckets, nozzles, and combustor hardware. Task 3--Advanced Methods for Combustion Monitoring and Control: The third task was originally to develop and validate advanced monitoring and control methods for coal/IGCC gas turbine combustion systems. This task was

  4. Research on coal-mine gas monitoring system controlled by annealing simulating algorithm

    NASA Astrophysics Data System (ADS)

    Zhou, Mengran; Li, Zhenbi

    2007-12-01

    This paper introduces the principle and schematic diagram of gas monitoring system by means of infrared method. Annealing simulating algorithm is adopted to find the whole optimum solution and the Metroplis criterion is used to make iterative algorithm combination optimization by control parameter decreasing aiming at solving large-scale combination optimization problem. Experiment result obtained by the performing scheme of realizing algorithm training and flow of realizing algorithm training indicates that annealing simulating algorithm applied to identify gas is better than traditional linear local search method. It makes the algorithm iterate to the optimum value rapidly so that the quality of the solution is improved efficiently. The CPU time is shortened and the identifying rate of gas is increased. For the mines with much-gas gushing fatalness the regional danger and disaster advanced forecast can be realized. The reliability of coal-mine safety is improved.

  5. Ground gas monitoring: implications for hydraulic fracturing and CO2 storage.

    PubMed

    Teasdale, Christopher J; Hall, Jean A; Martin, John P; Manning, David A C

    2014-12-02

    Understanding the exchange of carbon dioxide (CO2) and methane (CH4) between the geosphere and atmosphere is essential for the management of anthropogenic emissions. Human activities such as carbon capture and storage and hydraulic fracturing ("fracking") affect the natural system and pose risks to future global warming and to human health and safety if not engineered to a high standard. In this paper an innovative approach of expressing ground gas compositions is presented, using data derived from regulatory monitoring of boreholes in the unsaturated zone at infrequent intervals (typically 3 months) with data from a high frequency monitoring instrument deployed over periods of weeks. Similar highly variable trends are observed for time scales ranging from decades to hourly for boreholes located close to sanitary landfill sites. Additionally, high frequency monitoring data confirm the effect of meteorological controls on ground gas emissions; the maximum observed CH4 and CO2 concentrations in a borehole monitored over two weeks were 40.1% v/v and 8.5% v/v respectively, but for 70% of the monitoring period only air was present. There is a clear weakness in current point monitoring strategies that may miss emission events and this needs to be considered along with obtaining baseline data prior to starting any engineering activity.

  6. Multigas Leakage Correction in Static Environmental Chambers Using Sulfur Hexafluoride and Raman Spectroscopy.

    PubMed

    Jochum, Tobias; von Fischer, Joseph C; Trumbore, Susan; Popp, Jürgen; Frosch, Torsten

    2015-11-03

    In static environmental chamber experiments, the precision of gas flux measurements can be significantly improved by a thorough gas leakage correction to avoid under- or overestimation of biological activity such as respiration or photosynthesis. Especially in the case of small biological net gas exchange rates or gas accumulation phases during long environmental monitoring experiments, gas leakage fluxes could distort the analysis of the biogenic gas kinetics. Here we propose and demonstrate a general protocol for online correction of diffusion-driven gas leakage in plant chambers by simultaneous quantification of the inert tracer sulfur hexafluoride (SF6) and the investigated biogenic gases using enhanced Raman spectroscopy. By quantifying the leakage rates of carbon dioxide (CO2), methane (CH4), and hydrogen (H2) simultaneously with SF6 in the test chamber, their effective diffusivity ratios of approximately 1.60, 1.96, and 5.65 were determined, each related to SF6. Because our experiments suggest that the effective diffusivity ratios are reproducible for an individual static environmental chamber, even under varying concentration gradients and slight changes of the chamber sealing, an experimental method to quantify gas leakage fluxes by using effective diffusivity ratios and SF6 leakage fluxes is proposed. The method is demonstrated by quantifying the CO2 net exchange rate of a plant-soil ecosystem (Mirabilis jalapa). By knowing the effective chamber diffusivity ratio CO2/SF6 and the measured SF6 leakage rate during the experiment, the leakage contribution to the total CO2 exchange rate could be calculated and the biological net CO2 concentration change within the chamber atmosphere determined.

  7. Monitoring environmental effects of shale gas exploitation at Wysin in Poland.

    NASA Astrophysics Data System (ADS)

    Lasocki, Stanislaw; Mirek, Janusz; Bialon, Wojciech; Cielesta, Szymon; Lasak, Mateusz; Cesca, Simone; Lopez Comino, Jose Angel; Dahm, Torsten; Scarpa, Roberto; Gunning, Andrew; Montcoudiol, Nelly; Isherwood, Catherine; Jaroslawski, Janusz; Guzikowski, Jakub

    2017-04-01

    Environmental effects of shale gas exploration and exploitation are extensively studied in the framework of "Shale Gas Exploration and Exploitation Induced Risks" project (SHEER, H2020-LCE 16-2014-1). One of the main component of this study is on-site monitoring of the effects at Wysin shale-gas play of Polish Oil and Gas Company in Poland. This includes monitoring of seismicity and water and air quality. Surface seismic monitoring network consists of 6 surface broadband (BB) seismometers and 25 surface short-period (SP) seismometers The SPs are assembled into three small aperture arrays with 9, 8 and 8 stations, respectively, distributed in a triangle geometry at a distance of about 2-4 km from the hydrofracturing rig. Each array is complemented with one BB station. The three remaining BBs are located up to about 5 km from the rig. In addition 3 borehole broadband seismometers are located in three shallow boreholes. The groundwater monitoring makes use of four wells, which reach a main underground water reservoir. Three complementary datasets are collected: continuous monitoring of borehole data, laboratory analyses of water samples and field monitoring of water quality parameters. The continuous monitoring makes use of down-hole probes, which have been installed in each borehole. The probes record absolute pressure, temperature and electrical conductivity. In addition, a barometric probe has been installed above ground to record atmospheric pressure in order to allow conversion of absolute pressure to a water level. After collection, water samples are sent to an accredited laboratory for analysis. The field monitoring is undertaken during the sampling visits. Whilst the borehole is being purged, physico-chemical parameters are monitored using a multi-parameter probe. This measures and records temperature, specific conductivity, pH, dissolved oxygen and oxidation-reduction potential within the water. Hydrocarbon gas content within the water is below detection

  8. Gas Bubble Disease Monitoring and Research of Juvenile Salmonids : Annual Report 1996.

    SciTech Connect

    Maule, Alec G.; Beeman, John W.; Hans, Karen M.; Mesa, M.G.; Haner, P.; Warren, J.J.

    1997-10-01

    This document describes the project activities 1996--1997 contract year. This report is composed of three chapters which contain data and analyses of the three main elements of the project: field research to determine the vertical distribution of migrating juvenile salmonids, monitoring of juvenile migrants at dams on the Snake and Columbia rivers, and laboratory experiments to describe the progression of gas bubble disease signs leading to mortality. The major findings described in this report are: A miniature pressure-sensitive radio transmitter was found to be accurate and precise and, after compensation for water temperature, can be used to determine the depth of tagged-fish to within 0.32 m of the true depth (Chapter 1). Preliminary data from very few fish suggest that depth protects migrating juvenile steelhead from total dissolved gas supersaturation (Chapter 1). As in 1995, few fish had any signs of gas bubble disease, but it appeared that prevalence and severity increased as fish migrated downstream and in response to changing gas supersaturation (Chapter 2). It appeared to gas bubble disease was not a threat to migrating juvenile salmonids when total dissolved gas supersaturation was < 120% (Chapter 2). Laboratory studies suggest that external examinations are appropriate for determining the severity of gas bubble disease in juvenile salmonids (Chapter 3). The authors developed a new method for examining gill arches for intravascular bubbles by clamping the ventral aorta to reduce bleeding when arches were removed (Chapter 3). Despite an outbreak of bacterial kidney disease in the experimental fish, the data indicate that gas bubble disease is a progressive trauma that can be monitored (Chapter 3).

  9. Surface Measurements of Oxygen, Carbon Dioxide and Water Vapor Fluxes Using AN Automated Chamber System

    NASA Astrophysics Data System (ADS)

    Fentabil, M. M.; Fazackerley, S.; Nichol, C. F.

    2011-12-01

    The various soil respiration measurements that are available depend on measuring the emitted CO2 flux as organic carbon is respired aerobically. Comparative studies among the four well known methods (the open-flow infra-red gas analyzer method; the closed chamber method; the dynamic closed chamber method; and the alkali absorption method) under field conditions and laboratory experiments show differences. The discrepancies observed in these methods under field conditions could be evaluated by incorporating O2 flux measurement in addition to CO2 flux measurement. However, this is hampered by the absence of suitable equipment for measuring oxygen influx at the soil surface. A system to measure O2 fluxes at the soil surface using chamber methods has been developed. A gas handling subsystem and O2 analyser has been incorporated into an existing non-steady state automated chamber system originally designed for CO2 and H2O flux monitoring. The system consists of four 60 L soil chambers connected to temperature-controlled datalogger housing. During a measurement cycle, the chamber lid closes and the system measures changes of CO2/H2O and depletion of O2in the chamber headspace. Samples for CO2 /H2O circulate in a closed path between the chamber and an IR gas analyser. An air sample for O2 analysis is sub-sampled from this circulating air stream. Air samples for O2 are first dried using a two-stage Nafion drier. Mass flows and pressures are balanced at the pascal level prior to the gas passing into a ppm level fuel-cell oxygen analyser (Sable Systems Oxzilla). The chamber sample airstream is measured against a reference gas identically handled in a parallel air stream. A makeup gas of dry N2 is injected back to the chamber to return equimolar amounts of gas to replace the wet air removed, and hence prevent pressure fluctuation in the headspace of the chamber. The implementation of automated control of gas drying and sampling, pressure balancing, flow regulation and self

  10. Online drilling mud gas monitoring and sampling during drilling the Scandinavian Caledonides (COSC)

    NASA Astrophysics Data System (ADS)

    Wiersberg, Thomas; Almqvist, Bjarne; Klonowska, Iwona; Lorenz, Henning

    2015-04-01

    The COSC project (Collisional Orogeny in the Scandinavian Caledonides) drilled a 2496 m deep hole in Åre (Sweden) to deliver insights into mid-Palaeozoic mountain building processes from continent-continent collision, to improve our understanding of the hydrogeological-hydrochemical state and geothermal gradient of the mountain belt and to study the deep biosphere in the metamorphic rocks and crystalline basement. COSC was the first slimhole drilling project where online gasmonitoring of drilling mud was conducted during continuous wireline coring. Gas was continuously extracted at the surface from the circulating drilling mud with a gas-water separator, pumped in a nearby laboratory container and analysed in real-time with a quadrupole mass spectrometer for argon, methane, helium, carbon dioxide, nitrogen, oxygen, hydrogen, and krypton. Gas samples were taken from the gas line for laboratory studies on chemical composition of hydrocarbons, noble gas isotopes and stable isotopes. Every drill core created a gas peak identified in the drilling mud ~20-30 min after core arrival at the surface. With known core depth and surface arrival time, these gas peaks could be attributed to depth. As a result, nearly complete gas depth profiles at three meter intervals were obtained from 662 m (installation of the gas-water separator) to 2490 m depth. Maximum concentrations of non-atmospheric gasses in drilling mud were ~200 ppmv helium, ~300 ppmv methane and ~2 vol-% hydrogen. Helium peaks between ~900 m and 1000 m and correlates with enhanced concentrations of methane. Methane and hydrogen exhibit maximum concentrations below 1630 m depth where helium concentrations remain low. Integration of the drilling mud gas monitoring dataset with data from geophysical downhole logging and core analysis is ongoing to help clarifying provenances and origin of gasses.

  11. Ultrahigh sensitivity heavy noble gas detectors for long-term monitoring and monitoring air. 1998 annual progress report

    SciTech Connect

    Valentine, J.D.; Gross, K.

    1998-06-01

    'The primary objective of this research project is to develop heavy noble gas (krypton, xenon, and radon) detectors for: (1) long-term monitoring of transuranic waste, spent fuel, and other uranium and thorium bearing wastes, and (2) alpha particle air monitors that discriminate between radon emissions and other alpha emitters. A University of Cincinnati/Argonne National Laboratory (UC/ANL) Team has been assembled to complete this detector development project. DOE needs that are addressed by this project include improved long-term monitoring capability and improved air monitoring capability during remedial activities. Successful development and implementation of the proposed detection systems could significantly improve current capabilities with relatively simple and inexpensive equipment. As of June 1, 1998, the UC/ANL Team has: (1) made significant progress toward characterizing the fluid transfer process which is the basis for this detector development project and (2) evaluated several radiation detectors and several potential pulse processing schemes. The following discussion describes the progress made during the first year of this project and the implications of this progress.'

  12. Integrated gas analyzer for complete monitoring of turbine engine test cells.

    PubMed

    Markham, James R; Bush, Patrick M; Bonzani, Peter J; Scire, James J; Zaccardi, Vincent A; Jalbert, Paul A; Bryant, M Denise; Gardner, Donald G

    2004-01-01

    Fourier transform infrared (FT-IR) spectroscopy is proving to be reliable and economical for the quantification of many gas-phase species during testing and development of gas turbine engines in ground-based facilities such as sea-level test cells and altitude test cells. FT-IR measurement applications include engine-generated exhaust gases, facility air provided as input to engines, and ambient air in and around test cells. Potentially, the traditionally used assembly of many gas-specific single gas analyzers will be eliminated. However, the quest for a single instrument capable of complete gas-phase monitoring at turbine engine test cells has previously suffered since the FT-IR method cannot measure infrared-inactive oxygen molecules, a key operational gas to both air-breathing propulsion systems and test cell personnel. To further the quest, the FT-IR sensor used for the measurements presented in this article was modified by integration of a miniature, solid-state electrochemical oxygen sensor. Embedded in the FT-IR unit at a location near the long-effective-optical-path-length gas sampling cell, the amperometric oxygen sensor provides simultaneous, complementary information to the wealth of spectroscopic data provided by the FT-IR method.

  13. Continued Development of Compact Multi-gas Monitor for Life Support Systems Control in Space

    NASA Technical Reports Server (NTRS)

    Delgado-Alonso, Jesús; Phillips, Straun; Chullen, Cinda; Quinn, Gregory

    2016-01-01

    Miniature optic gas sensors (MOGS) based on luminescent materials have shown great potential as alternatives to Near-Infrared-based gas sensor systems for the advanced space suit portable life support system (PLSS). The unique capability of MOGS for carbon dioxide and oxygen monitoring under wet conditions has been reported, as has the fast recovery of MOGS humidity sensors after long periods of being wet. Lower volume and power requirements are also potential advantages of MOGS over both traditional and advanced Non-Dispersive Infrared (NDIR) gas sensors, which have shown so far longer life than luminescent sensors. This paper presents the most recent results in the development and analytical validation of a compact multi-gas sensor unit based on luminescent sensors for the PLSS. Results of extensive testing are presented, including studies conducted at Intelligent Optical Systems laboratories, a United Technology Corporation Aerospace Systems (UTAS) laboratory, and a Johnson Space Center laboratory. The potential of this sensor technology for gas monitoring in PLSSs and other life support systems and the advantages and limitations found through detailed sensor validation are discussed.

  14. Continued Development of Compact Multi-Gas Monitor for Life Support Systems Control in Space

    NASA Technical Reports Server (NTRS)

    Delgado, Jesus; Phillips, Straun; Chullen, Cinda

    2015-01-01

    Miniature optic gas sensors (MOGS) based on luminescent materials have shown great potential as alternatives to NIR-based gas sensor systems for the Portable Life Support System (PLSS). The unique capability of MOGS for carbon dioxide and oxygen monitoring under wet conditions has been reported, as has the fast recovery of MOGS humidity sensors after long periods of being wet. Lower volume and power requirements are also potential advantages of MOGS over both traditional and advanced Non-Dispersive Infrared (NDIR) gas sensors, which have shown so far longer life than luminescent sensors. In this paper we present the most recent results in the development and analytical validation of a compact multi-gas sensor unit based on luminescent sensors for the PLSS. Results of extensive testing are presented, including studies conducted at Intelligent Optical Systems laboratories, a United Technology Corporation Aerospace Systems (UTAS) laboratory, and a Johnson Space Center laboratory. The potential of this sensor technology for gas monitoring in PLSSs and other life support systems and the advantages and limitations found through detailed sensor validation are discussed.

  15. Real-time drilling mud gas monitoring for qualitative evaluation of hydrocarbon gas composition during deep sea drilling in the Nankai Trough Kumano Basin.

    PubMed

    Hammerschmidt, Sebastian B; Wiersberg, Thomas; Heuer, Verena B; Wendt, Jenny; Erzinger, Jörg; Kopf, Achim

    2014-01-01

    Integrated Ocean Drilling Program Expedition 338 was the second scientific expedition with D/V Chikyu during which riser drilling was conducted as part of the Nankai Trough Seismogenic Zone Experiment. Riser drilling enabled sampling and real-time monitoring of drilling mud gas with an onboard scientific drilling mud gas monitoring system ("SciGas"). A second, independent system was provided by Geoservices, a commercial mud logging service. Both systems allowed the determination of (non-) hydrocarbon gas, while the SciGas system also monitored the methane carbon isotope ratio (δ(13)CCH4). The hydrocarbon gas composition was predominated by methane (> 1%), while ethane and propane were up to two orders of magnitude lower. δ(13)CCH4 values suggested an onset of thermogenic gas not earlier than 1600 meter below seafloor. This study aims on evaluating the onboard data and subsequent geological interpretations by conducting shorebased analyses of drilling mud gas samples. During shipboard monitoring of drilling mud gas the SciGas and Geoservices systems recorded up to 8.64% and 16.4% methane, respectively. Ethane and propane concentrations reached up to 0.03 and 0.013%, respectively, in the SciGas system, but 0.09% and 0.23% in the Geoservices data. Shorebased analyses of discrete samples by gas chromatography showed a gas composition with ~0.01 to 1.04% methane, 2 - 18 ppmv ethane, and 2 - 4 ppmv propane. Quadruple mass spectrometry yielded similar results for methane (0.04 to 4.98%). With δD values between -171‰ and -164‰, the stable hydrogen isotopic composition of methane showed little downhole variability. Although the two independent mud gas monitoring systems and shorebased analysis of discrete gas sample yielded different absolute concentrations they all agree well with respect to downhole variations of hydrocarbon gases. The data point to predominantly biogenic methane sources but suggest some contribution from thermogenic sources at depth, probably due

  16. Plant organ chambers in plant physiology field research

    SciTech Connect

    Sinclair, T.R.

    1980-10-01

    Plant organ chambers used for measuring gas exchange demonstrate that with due-concern for the chamber environment and for the normal growth of the plants, useful data on physiological performance under field conditions can be collected. Recent advances in electronics, particularly the development of minicomputers and microprocessors, have greatly expanded the potential for monitoring and controlling plant organ chambers in field physiology research. These tools allow the scope of the research to be considerably broadened because many chambers can be observed essentially simultaneously and continuously on a long-term basis. The inherent limitations of artificialities and ambiguities in the data can be minimized by good control of the chamber environment and a multiplicity of chambers. While these technological advances allow intensive field physiological research, they also require a substantial commitment from the experimenter. During the data collection, a continuing, long-term effort is required to assure high quality data. Having completed the data collection, the experimenter is confronted with a very large volume of data that must be analyzed and interpreted. Yet, the rewards of these commitments appear to be an ever-increasing understanding of the physiological processes existing in plants grown under field conditions.

  17. Evaluation of a transcutaneous blood gas monitoring system in critically ill dogs.

    PubMed

    Holowaychuk, Marie K; Fujita, Hiroshi; Bersenas, Alexa M E

    2014-01-01

    To describe the use of a transcutaneous blood gas monitoring system in critically ill dogs, determine if transcutaneous and arterial blood gas values have good agreement, and verify if clinical or laboratory variables are correlated with differences between transcutaneous and arterial blood gas measurements. Prospective observational study. University teaching hospital ICU. Twenty-three client-owned dogs. In critically ill dogs undergoing arterial blood gas monitoring, a transcutaneous blood gas monitor was used to measure transcutaneous partial pressure of carbon dioxide (PtcCO2 ) and transcutaneous partial pressure of oxygen (PtcO2 ) values 30 minutes after sensor placement, which were compared to PaCO2 and PaO2 values measured simultaneously. Clinical and laboratory variables were concurrently recorded to determine if they were correlated with the difference between transcutaneous and arterial blood gas measurements. Bland-Altman analysis revealed a mean bias of 4.6 ± 26.3 mm Hg (limits of agreement [LOA]: -46.9/+56.1 mm Hg) between PtcO2 and PaO2 and a mean bias of 9.3 ± 8.5 mm Hg (LOA: -7.5/+26.0 mm Hg) between PtcCO2 and PaCO2 . The difference between PtcCO2 -PaCO2 was strongly negatively correlated with HCO3 (-) (r(2) = 0.52, P < 0.001) and PaCO2 (r(2) = 0.58, P < 0.001) and weakly positively correlated with diastolic blood pressure (r(2) = 0.21, P = 0.044), whereas the difference between PtcCO2 -PaCO2 was moderately negatively correlated with diastolic blood pressure (r(2) = 0.33, P = 0.008). Agreement between transcutaneous and arterial PO2 and PCO2 measurements in these critically ill dogs was inferior to that reported in similar adult and pediatric human studies. The transcutaneous monitor consistently over-estimated PaO2 and PaCO2 and should not be used to replace arterial blood gas measurements in critically ill dogs requiring blood gas interpretation. © Veterinary Emergency and Critical Care Society 2014.

  18. Preconcentration modeling for the optimization of a micro gas preconcentrator applied to environmental monitoring.

    PubMed

    Camara, Malick; Breuil, Philippe; Briand, Danick; Viricelle, Jean-Paul; Pijolat, Christophe; de Rooij, Nico F

    2015-04-21

    This paper presents the optimization of a micro gas preconcentrator (μ-GP) system applied to atmospheric pollution monitoring, with the help of a complete modeling of the preconcentration cycle. Two different approaches based on kinetic equations are used to illustrate the behavior of the micro gas preconcentrator for given experimental conditions. The need for high adsorption flow and heating rate and for low desorption flow and detection volume is demonstrated in this paper. Preliminary to this optimization, the preconcentration factor is discussed and a definition is proposed.

  19. Monitoring of conditions inside gas aggregation cluster source during production of Ti/TiOx nanoparticles

    NASA Astrophysics Data System (ADS)

    Kousal, J.; Kolpaková, A.; Shelemin, A.; Kudrna, P.; Tichý, M.; Kylián, O.; Hanuš, J.; Choukourov, A.; Biederman, H.

    2017-10-01

    Gas aggregation sources are nowadays rather widely used in the research community for producing nanoparticles. However, the direct diagnostics of conditions inside the source are relatively scarce. In this work, we focused on monitoring the plasma parameters and the composition of the gas during the production of the TiOx nanoparticles. We studied the role of oxygen in the aggregation process and the influence of the presence of the particles on the plasma. The construction of the source allowed us to make a 2D map of the plasma parameters inside the source.

  20. Customized design of electronic noses placed on top of air-lift bioreactors for in situ monitoring the off-gas patterns.

    PubMed

    Rosi, Pablo E; Miscoria, Silvia A; Bernik, Delia L; Martín Negri, R

    2012-06-01

    A specially designed electronic nose was coupled to an air-lift bioreactor in order to perform on-line monitoring of released vapors. The sensor array was placed at the top of the bioreactor sensing the headspace in equilibrium with the evolving liquor at any time without the need of aspiration and pumping of gases into a separated sensor chamber. The device was applied to follow the off-gas of a bioreactor with Acidithiobacillus thiooxidans grown on beds of elemental sulfur under aerobic conditions. Evolution was monitored by acid titration, pH and optical density measurements. The electronic nose was capable to differentiate each day of reactor evolution since inoculation within periods marked off culture medium replacements using multivariate data analysis. Excellent discrimination was obtained indicating the potentiality for on-line monitoring in non-perturbed bioreactors. The prospects for electronic nose/bioreactor merging are valuable for whatever the bacterial strain or consortium used in terms of scent markers to monitor biochemical processes.

  1. Underground Fiber-Optic Differential Absorption Instrument for Monitoring Carbon Dioxide Soil Gas Concentrations for Carbon Sequestration Site Monitoring

    NASA Astrophysics Data System (ADS)

    Nehrir, A. R.; Humphries, S. D.; Repasky, K. S.; Carlsten, J. L.; Spangler, L. H.; Dobeck, L. M.

    2007-12-01

    The burning of fossil fuels has resulted in higher carbon dioxide (CO2) concentrations in the atmosphere with potential impacts on the Earth's climate. The use of fossil fuels is predicted to grow over the next several decades with the potential for further increasing the atmospheric concentration of CO2. A proposed method of diminishing the impacts of increased CO2 on the Earth's climate is to capture and store the CO2 in geologic storage sites. One issue with underground sequestration of CO2 is the ability to monitor sequestration sites to verify the integrity of the storage of the CO2. An underground fiber optic differential absorption instrument based on a tunable distributed feedback (DFB) diode laser is being developed at Montana State University to detect small changes in CO2 soil gas concentration in an effort to monitor the overall integrity of the sequestration storage site. The fiber optic instrument exploits the 2003-2006 nm region of the spectrum which contains four CO2 absorption lines. Light from the DFB laser is delivered to an underground absorption cell one meter in length via a single mode optical fiber. The normalized transmission is measured by tuning the DFB diode laser across these four absorption lines and the results are used to determine the CO2 soil gas concentration. A description of this instrument will be presented including the instrument design, operation, and performance characteristics. A field site for testing the performance of CO2 detection instruments and techniques has been developed by the Zero Emissions Research Technology (ZERT) group at Montana State University. The field site allows a controlled flow rate of CO2 to be released underground through a 100 m long horizontal pipe placed below the water table. Two release experiments were performed this past summer with flow rates of 0.1 and 0.3 tons CO2/day. The first release experiment lasted ten days while the second release lasted seven days. Measurements taken with the

  2. Unraveling fabrication and calibration of wearable gas monitor for use under free-living conditions.

    PubMed

    Yue Deng; Cheng Chen; Tsow, Francis; Xiaojun Xian; Forzani, Erica

    2016-08-01

    Volatile organic compounds (VOC) are organic chemicals that have high vapor pressure at regular conditions. Some VOC could be dangerous to human health, therefore it is important to determine real-time indoor and outdoor personal exposures to VOC. To achieve this goal, our group has developed a wearable gas monitor with a complete sensor fabrication and calibration protocol for free-living conditions. Correction factors for calibrating the sensors, including sensitivity, aging effect, and temperature effect are implemented into a Quick Response Code (QR code), so that the pre-calibrated quartz tuning fork (QTF) sensor can be used with the wearable monitor under free-living conditions.

  3. Novel industrial application: flammable and toxic gas monitoring in the printing industry

    NASA Astrophysics Data System (ADS)

    Jacobson, Esther; Spector, Yechiel

    1999-12-01

    The present paper describes an Open Path Electro-Optical Gas Monitoring System specifically designed for in-situ on-line monitoring of flammable and toxic atmospheres in the Printing Industry in general, and for air-duct applications in particular. The printing industry posies unique fire hazards due to the variety of toxic and flammable chemical employed in the various printing process. Flammable material such as paper, ink, solvents, thinners, metal powders, cornstarch powders, cloth, synthetic materials are frequently used in the printing industry in several processes such as letter-pressing, lithography, screen printing etc.

  4. Ablation-erosion analyses of various fusion material surfaces and developments of surface erosion monitors for notification of fusion chamber maintenance times, as an example: Visible light transparent SiC and up-conversion phosphors applied to plasma facing surface structures, useful for versatile purposes to protect and diagnose fusion chambers and so on

    NASA Astrophysics Data System (ADS)

    Kasuya, K.; Motokoshi, S.; Taniguchi, S.; Nakai, M.; Tokunaga, K.; Kolacek, K.; Schmidt, J.; Frolov, O.; Straus, J.; Matejicek, J.; Choukourov, A.

    2017-01-01

    Two kinds of pulsed lasers in Japan and Czech Republic were used to irradiate various sample materials to investigate the surface erosion thresholds under very hazardous environments including nuclear fusion chambers. The first was ArF laser in ILT and the second was XUV laser in IPP. These data were in-cooperated with our former data to build up our material strength data for our succeeding applications of various materials to a variety of fields. As an example, we proposed surface erosion monitors to notice the fusion chamber maintenance times with which the facilities can be protected from the collapses under very severe operation conditions. These kinds of monitors are expected to be useful for future different kinds of mechanical structures not only for the fusion chambers but also various chambers for many purposes. Special upconversion phosphors are also newly proposed to be used as the candidate materials to measure the thermal inputs onto the front surfaces of the armor structures. Optical transparent SiC was also newly tested to enrich our data base for our future diagnostic and protection possibilities.

  5. Monitoring Requirements and Methods for Greenhouse Gas Management and Climate Change Detection

    NASA Astrophysics Data System (ADS)

    Birdsey, R.; Pan, Y.; Clark, K.; Hom, J.

    2007-12-01

    Climate change policy and management require monitoring data to support decision making. Availability of good data about past trends, and projections based on reasonable assumptions and models, can support debate about response options and avoid the pitfall of arguing about information quality. A hierarchical or multi-tier approach to environmental monitoring has been used efficiently for many decades, and can be linked with experiments and process modeling to improve natural resource assessments. Consideration of spatial and temporal scale can align data requirements with the information needed to facilitate separation of causal factors, e.g., factoring out natural effects from human-induced effects on the carbon cycle. Here we describe a 3-tier integrated monitoring hierarchy: intensive process-level monitoring, landscape-scale monitoring, and regional monitoring. Information at each tier may be used independently or integrated across tiers. Methods to integrate information include statistical techniques for diagnostic analysis, and ecosystem models for prognostic analysis. We illustrate the methods and results for each tier using data and analyses for the Pinelands Management Area of New Jersey, a reserved area of 360,000 ha. A cluster of flux towers and associated intensive-site measurements comprises the process monitoring. A network of biometric monitoring sites represents the landscape conditions, and forest inventory with remote sensing is used to characterize the region. This approach is capable of closing the regional carbon budget, i.e., accounting for all exchanges of carbon between the land, atmosphere, and ocean. It is also an excellent platform for monitoring the effects of climate change and factoring out different effects -- the system was designed to provide information about dangerous fire weather and identify needs to manage wildfire fuels. The New Jersey Pinelands site is part of a national network of multi-scale monitoring sites that can meet

  6. Continuous Seafloor Gas Hydrate Monitoring on the Ocean Networks Canada NEPTUNE Cabled Observatory

    NASA Astrophysics Data System (ADS)

    Scherwath, M.; Heesemann, M.; Moran, K.; Insua, T. L.; Roemer, M.; Riedel, M.; Spence, G.; Thomsen, L.; Purser, A.

    2014-12-01

    Long-term seafloor experiments provide high-resolution data that allow new kinds of observations on the dynamics and variability of gas hydrates. In the north-east Pacific, Canadian as well as US efforts on building cabled seafloor observatories enable the scientific community to study the Cascadia margin gas hydrates at various locations independent of dedicated ship cruises and unstable weather, without power saving restrictions and with near realtime access to the data and the ability to influence the in-situ data acquisition in reaction to events. We show scientific highlights from Barkley Canyon and Clayoquot Slope off Vancouver Island on of the gas hydrate stability and variability on and below the seafloor as well as gas release into the water column, using some standard measurements from core instruments such as temperature, salinity, bottom pressure, currents, as well as sonar, seismometer and camera image data. Correlations of these various data sets shed light on the dependence of the observed gas hydrate dynamics on various environmental factors, some still subject to debate and longer-term monitoring requirements. Global efforts on cabling the seafloor elsewhere are underway and an exciting future on gas hydrate research lies ahead. Ocean Networks Canada invites the research community to participate, propose experiments, download data and collaborate (www.oceannetworks.ca).

  7. Optical Multi-Gas Monitor Technology Demonstration on the International Space Station

    NASA Technical Reports Server (NTRS)

    Pilgrim, Jeffrey S.; Wood, William R.; Casias, Miguel E.; Vakhtin, Andrei B,; Johnson, Michael D.; Mudgett, Paul D.

    2014-01-01

    There are a variety of both portable and fixed gas monitors onboard the International Space Station (ISS). Devices range from rack-mounted mass spectrometers to hand-held electrochemical sensors. An optical Multi-Gas Monitor has been developed as an ISS Technology Demonstration to evaluate long-term continuous measurement of 4 gases. Based on tunable diode laser spectroscopy, this technology offers unprecedented selectivity, concentration range, precision, and calibration stability. The monitor utilizes the combination of high performance laser absorption spectroscopy with a rugged optical path length enhancement cell that is nearly impossible to misalign. The enhancement cell serves simultaneously as the measurement sampling cell for multiple laser channels operating within a common measurement volume. Four laser diode based detection channels allow quantitative determination of ISS cabin concentrations of water vapor (humidity), carbon dioxide, ammonia and oxygen. Each channel utilizes a separate vertical cavity surface emitting laser (VCSEL) at a different wavelength. In addition to measuring major air constituents in their relevant ranges, the multiple gas monitor provides real time quantitative gaseous ammonia measurements between 5 and 20,000 parts-per-million (ppm). A small ventilation fan draws air with no pumps or valves into the enclosure in which analysis occurs. Power draw is only about 3 W from USB sources when installed in Nanoracks or when connected to 28V source from any EXPRESS rack interface. Internal battery power can run the sensor for over 20 hours during portable operation. The sensor is controlled digitally with an FPGA/microcontroller architecture that stores data internally while displaying running average measurements on an LCD screen and interfacing with the rack or laptop via USB. Design, construction and certification of the Multi-Gas Monitor were a joint effort between Vista Photonics, Nanoracks and NASA-Johnson Space Center (JSC

  8. Polynomials and Neural Networks for Gas Turbine Monitoring: a Comparative Study

    NASA Astrophysics Data System (ADS)

    Loboda, Igor; Feldshteyn, Yakov

    2011-09-01

    Gas turbine health monitoring includes the common stages of problem detection, fault identification, and prognostics. To extract useful diagnostic information from raw recorded data, these stages require a preliminary operation of computing differences between measurements and an engine baseline, which is a function of engine operating conditions. These deviations of measured values from the baseline data can be good indicators of engine health. However, their quality and the success of all diagnostic stages strongly depend on the adequacy of the baseline model employed and, in particular, on the mathematical techniques applied to create it. To create a baseline model, we have applied polynomials and the least squares method for computing the coefficients over a long period of time. Methods were proposed to enhance such a polynomial-based model. The resulting accuracy was sufficient for reliable monitoring of gas turbine deterioration effects. The polynomials previously investigated thus far are used in the present study as a standard for evaluating artificial neural networks, a very popular technique in gas turbine diagnostics. The focus of this comparative study is to verify whether the use of networks results in a better description of the engine baseline. Extensive field data for two different industrial gas turbines were used to compare these two techniques under various conditions. The deviations were computed for all available data, and the quality of the resulting deviation plots was compared visually. The mean error of the baseline model was used as an additional criterion for comparing the techniques. To find the best network configurations, many network variations were realised and compared with the polynomials. Although the neural networks studied were found to be close to the polynomials in accuracy, they did not exceed the polynomials in any variation. In this way, it seems that polynomials can be successfully used for engine monitoring, at least for

  9. Laser Spectroscopy Multi-Gas Monitor: Results of Technology Demonstration on ISS

    NASA Technical Reports Server (NTRS)

    Mudgett, Paul D.; Pilgrim, Jeffrey S.

    2015-01-01

    Tunable diode laser spectroscopy (TDLS) is an up and coming trace and major gas monitoring technology with unmatched selectivity, range and stability. The technology demonstration of the 4 gas Multi-Gas Monitor (MGM), reported at the 2014 ICES conference, operated continuously on the International Space Station (ISS) for nearly a year. The MGM is designed to measure oxygen, carbon dioxide, ammonia and water vapor in ambient cabin air in a low power, relatively compact device. While on board, the MGM experienced a number of challenges, unplanned and planned, including a test of the ammonia channel using a commercial medical ammonia inhalant. Data from the unit was downlinked once per week and compared with other analytical resources on board, notably the Major Constituent Analyzer (MCA), a magnetic sector mass spectrometer. MGM spent the majority of the time installed in the Nanoracks Frame 2 payload facility in front breathing mode (sampling the ambient environment of the Japanese Experiment Module), but was also used to analyze recirculated rack air. The capability of the MGM to be operated in portable mode (via internal rechargeable lithium ion polymer batteries or by plugging into any Express Rack 28VDC connector) was a part of the usability demonstration. Results to date show unprecedented stability and accuracy of the MGM vs. the MCA for oxygen and carbon dioxide. The ammonia challenge (approx. 75 ppm) was successful as well, showing very rapid response time in both directions. Work on an expansion of capability in a next generation MGM has just begun. Combustion products and hydrazine are being added to the measurable target analytes. An 8 to 10 gas monitor (aka Gas Tricorder 1.0) is envisioned for use on ISS, Orion and Exploration missions.

  10. Methods to produce calibration mixtures for anesthetic gas monitors and how to perform volumetric calculations on anesthetic gases.

    PubMed

    Christensen, P L; Nielsen, J; Kann, T

    1992-10-01

    A simple procedure for making calibration mixtures of oxygen and the anesthetic gases isoflurane, enflurane, and halothane is described. One to ten grams of the anesthetic substance is evaporated in a closed, 11,361-cc glass bottle filled with oxygen gas at atmospheric pressure. The carefully mixed gas is used to calibrate anesthetic gas monitors. By comparison of calculated and measured volumetric results it is shown that at atmospheric conditions the volumetric behavior of anesthetic gas mixtures can be described with reasonable accuracy using the ideal gas law. A procedure is described for calculating the deviation from ideal gas behavior in cases in which this is needed.

  11. Optical Multi-Gas Monitor Technology Demonstration on the International Space Station

    NASA Technical Reports Server (NTRS)

    Pilgrim, Jeffrey S.; Wood, William R.; Casias, Miguel E.; Vakhtin, Andrei B.; Johnson, Michael D.; Mudgett, Paul D.

    2014-01-01

    The International Space Station (ISS) employs a suite of portable and permanently located gas monitors to insure crew health and safety. These sensors are tasked with functions ranging from fixed mass spectrometer based major constituents analysis to portable electrochemical sensor based combustion product monitoring. An all optical multigas sensor is being developed that can provide the specificity of a mass spectrometer with the portability of an electrochemical cell. The technology, developed under the Small Business Innovation Research program, allows for an architecture that is rugged, compact and low power. A four gas version called the Multi-Gas Monitor was launched to ISS in November 2013 aboard Soyuz and activated in February 2014. The portable instrument is comprised of a major constituents analyzer (water vapor, carbon dioxide, oxygen) and high dynamic range real-time ammonia sensor. All species are sensed inside the same enhanced path length optical cell with a separate vertical cavity surface emitting laser (VCSEL) targeted at each species. The prototype is controlled digitally with a field-programmable gate array/microcontroller architecture. The optical and electronic approaches are designed for scalability and future versions could add three important acid gases and carbon monoxide combustion product gases to the four species already sensed. Results obtained to date from the technology demonstration on ISS are presented and discussed.

  12. Air Monitoring System in Elders' Apartment with QCM Type Gas Sensors

    NASA Astrophysics Data System (ADS)

    Kikuchi, Masashi; Ito, Tsukasa; Shiratori, Seimei

    The gas monitoring system for elders' apartment using QCM sensors was newly developed. The QCM sensors for sulfide gas and ammonia gas were used for this system. The system for bodily wastes was fabricated and applied to nursing care system in elders' apartment. This system is composed by the sensor unit, communication unit and data server. Care person can see whether the linen should be changed or not without seeing over each room. The QCM sensors have some problems such as the interference of humidity and temperature, therefore these influences were dissolved using humidity sensor and temperature sensor as feedback source. The sensors were placed in several points of elders' apartment for 2 weeks. This system can be used in elders' apartment successfully.

  13. Effect of headspace mixing in static chambers and sampling protocol on calculated CH4 fluxes from soils

    NASA Astrophysics Data System (ADS)

    Juszczak, R.; Pihlatie, M.; Christiansen, J. R.; Giebels, M.; Schreiber, P.; Aaltonen, H.; Korhonen, J.; Rasilo, T.; Chojnicki, B. H.; Urbaniak, M.

    2009-04-01

    Closed static chambers are often used for greenhouse gas flux measurements from soils. The type of chamber, chamber handling and sampling protocol can influence the measurements. In most cases the calculated fluxes are suspected to be underestimated mainly because of reduction of gas diffusion from the soil to chamber headspace due to changed trace gas concentration gradient. Thus, fans are often applied to obtain better mixing of the air inside the chamber headspace and in turn reduce the negative effect of decreased concentration gradient. The open question is, however, to which extent the fluxes are changed by fans and whether they still remain underestimated or may even be overestimated? On the other hand, different sampling protocols are used assuming that they do not affect the flux measurements. To test different types of static chambers and different sampling procedures applied for measurement of greenhouse gas (CH4 and N2O) fluxes a chamber calibration campaign was organized at Hyytiälä Forestry Field Station in Southern Finland during August-October 2008. The main aim of the campaign was to quantitatively assess the uncertaintities and errors related to static chamber measurements. During this campaign static chambers were tested for 5 different CH4 and N2O flux levels with 3 different soil conditions (moisture and porosity) in a calibration tank described by Pumpanen et al. (2004). Among the different experiments, several special tests were carried out with the closed static chambers. Here, results of two special tests are presented to document whether 1) the air mixing inside the chamber headspace, 2) different sampling procedures influence the CH4 fluxes, and 3) how different calculation methods lead to varying results. Two static chambers of different volumes (65.5 and 195 liters) but with the same circular shape and surface area were connected to a LOS GATOS fats methane analyzer. The CH4 concentration inside the chamber headspace was monitored

  14. Metal oxide nanowire gas sensors for indoor and outdoor environmental monitoring

    NASA Astrophysics Data System (ADS)

    Köck, Anton; Brunet, Elise; Freudenberg, Oliver; Gamauf, Christoph; Kraft, Jochen; Mutinati, Giorgio C.; Maier, Thomas; Nemecek, Alexander; Schrank, Franz; Schrems, Martin; Siegele, Martin; Siegert, Jörg; Steinhauer, Stephan; Teva, Jordi

    2013-05-01

    We present performance results of SnO2 and CuO nanowire gas sensor devices, where single and multi-nanowire device configurations have been employed in order to optimize sensor design. In particular the response to the target gases CO, H2, and H2S has been measured in dry and humid air; both the SnO2 and CuO nanowire sensors are able to detect CO in the low ppm concentration range, which is important for environmental monitoring. The CuO multi-nanowire devices show an extraordinary high response to H2S with sensitivity in the low ppb concentration. We present our developments of CMOS technology based micro-hotplates, which are employed as platform for gas sensitive thin films and nanowires. Potential heterogeneous integration of nanowires on the micro-hotplate chips as well as an approach towards gas sensor arrays is discussed. We conclude that CMOS integrated multi-nanowire gas sensors are highly promising candidates for the practical realization of multi-parameter sensor devices for indoor and outdoor environmental monitoring.

  15. Studies on automatic hot gas reader used in the countrywide personnel monitoring programme.

    PubMed

    Kumar, Munish; Alagu Raja, E; Prasad, L C; Popli, K L; Kher, R K; Bhatt, B C

    2005-01-01

    In India, approximately 58,000 radiation workers are monitored using locally made CaSO4:Dy teflon embedded thermoluminescence dosemeter (TLD) badge system. The automatic hot gas readers developed locally are also used in TL measurements. The hot gas reader system has many advantages over the manual readers used previously and has completely replaced the manual reader system in all TLD personnel monitoring units in India. In the present study, the new reader system is studied and a theoretical attempt has been made to interpret the experimentally obtained results. The glow curves are generated theoretically and are also plotted experimentally. It has been found that the heat capacity of the heating gas, which is responsible for the transfer of heat, has a role in deciding the position of peak and is verified experimentally using different gas flow rates of nitrogen and argon as heating gases in the reader. The theoretical study may also be helpful in fitting the experimentally obtained glow curves and, therefore, the elimination of unwanted non-radiation-induced contributions, such as dark current, electronic spikes, light leakage and triboluminescence that generally distort the glow curve shape, can be achieved.

  16. Enabling Technology for Monitoring & Predicting Gas Turbine Health & Performance in COAL IGCC Powerplants

    SciTech Connect

    Kenneth A. Yackly

    2004-09-30

    The ''Enabling & Information Technology To Increase RAM for Advanced Powerplants'' program, by DOE request, has been re-directed, de-scoped to two tasks, shortened to a 2-year period of performance, and refocused to develop, validate and accelerate the commercial use of enabling materials technologies and sensors for Coal IGCC powerplants. The new program has been re-titled as ''Enabling Technology for Monitoring & Predicting Gas Turbine Health & Performance in IGCC Powerplants'' to better match the new scope. This technical progress report summarizes the work accomplished in the reporting period April 1, 2004 to August 31, 2004 on the revised Re-Directed and De-Scoped program activity. The program Tasks are: Task 1--IGCC Environmental Impact on high Temperature Materials: This first materials task has been refocused to address Coal IGCC environmental impacts on high temperature materials use in gas turbines and remains in the program. This task will screen material performance and quantify the effects of high temperature erosion and corrosion of hot gas path materials in Coal IGCC applications. The materials of interest will include those in current service as well as advanced, high-performance alloys and coatings. Task 2--Material In-Service Health Monitoring: This second task develops and demonstrates new sensor technologies to determine the in-service health of advanced technology Coal IGCC powerplants, and remains in the program with a reduced scope. Its focus is now on only two critical sensor need areas for advanced Coal IGCC gas turbines: (1) Fuel Quality Sensor for detection of fuel impurities that could lead to rapid component degradation, and a Fuel Heating Value Sensor to rapidly determine the fuel heating value for more precise control of the gas turbine, and (2) Infra-Red Pyrometer to continuously measure the temperature of gas turbine buckets, nozzles, and combustor hardware.

  17. NDIR Gas Sensor for Spatial Monitoring of Carbon Dioxide Concentrations in Naturally Ventilated Livestock Buildings

    PubMed Central

    Mendes, Luciano B.; Ogink, Nico W. M.; Edouard, Nadège; van Dooren, Hendrik Jan C.; Tinôco, Ilda de Fátima F.; Mosquera, Julio

    2015-01-01

    The tracer gas ratio method, using CO2 as natural tracer, has been suggested as a pragmatic option to measure emissions from naturally ventilated (NV) barns without the need to directly estimate the ventilation rate. The aim of this research was to assess the performance of a low-cost Non-Dispersive Infra-Red (NDIR) sensor for intensive spatial field monitoring of CO2 concentrations in a NV dairy cow house. This was achieved by comparing NDIR sensors with two commonly applied methods, a Photo-Acoustic Spectroscope (PAS) Gas Monitor and an Open-Path laser (OP-laser). First, calibrations for the NDIR sensors were obtained in the laboratory. Then, the NDIR sensors were placed in a dairy cow barn for comparison with the PAS and OP-laser methods. The main conclusions were: (a) in order to represent the overall barn CO2 concentration of the dairy cow barn, the number of NDIR sensors to be accounted for average concentration calculation was dependent on barn length and on barn area occupation; and (b) the NDIR CO2 sensors are suitable for multi-point monitoring of CO2 concentrations in NV livestock barns, being a feasible alternative for the PAS and the OP-laser methods to monitor single-point or averaged spatial CO2 concentrations in livestock barns. PMID:25985166

  18. NDIR Gas Sensor for Spatial Monitoring of Carbon Dioxide Concentrations in Naturally Ventilated Livestock Buildings.

    PubMed

    Mendes, Luciano B; Ogink, Nico W M; Edouard, Nadège; van Dooren, Hendrik Jan C; Tinôco, Ilda de Fátima F; Mosquera, Julio

    2015-05-13

    The tracer gas ratio method, using CO2 as natural tracer, has been suggested as a pragmatic option to measure emissions from naturally ventilated (NV) barns without the need to directly estimate the ventilation rate. The aim of this research was to assess the performance of a low-cost Non-Dispersive Infra-Red (NDIR) sensor for intensive spatial field monitoring of CO2 concentrations in a NV dairy cow house. This was achieved by comparing NDIR sensors with two commonly applied methods, a Photo-Acoustic Spectroscope (PAS) Gas Monitor and an Open-Path laser (OP-laser). First, calibrations for the NDIR sensors were obtained in the laboratory. Then, the NDIR sensors were placed in a dairy cow barn for comparison with the PAS and OP-laser methods. The main conclusions were: (a) in order to represent the overall barn CO2 concentration of the dairy cow barn, the number of NDIR sensors to be accounted for average concentration calculation was dependent on barn length and on barn area occupation; and (b) the NDIR CO2 sensors are suitable for multi-point monitoring of CO2 concentrations in NV livestock barns, being a feasible alternative for the PAS and the OP-laser methods to monitor single-point or averaged spatial CO2 concentrations in livestock barns.

  19. One year continuous soil gas monitoring above an EGR test site

    NASA Astrophysics Data System (ADS)

    Furche, Markus; Schlömer, Stefan; Faber, Eckhard; Dumke, Ingolf

    2010-05-01

    Setup and first results of an ongoing research activity are presented, which is funded by the German Geotechnologien program within in the joint project CLEAN (CO2 Large Scale Enhanced Gas Recovery in the Altmark Natural Gas Field). The task is to establish several soil gas monitoring stations above a partly exhausted gas field in the Altmark which will be used for an enhanced gas recovery (EGR) test by injecting CO2 into the reservoir. The aim is to optimize the monitoring technique including automatic data transfer and data exploitation and to understand mechanisms of natural variations of soil gas concentrations in the specific area. Furthermore the suitability of these measurements as a contribution to leakage detection shall be evaluated. A network of 13 gauging stations for the measurement of CO2 is working continuously for about one year. They are spread over an area of 8 x 3 km and are situated in direct vicinity of existing deep boreholes as the most likely locations for possible leakage. In addition one station is placed far outside the gasfield as a reference point. The technique applied to measure soil gas concentrations uses a gas stream circulating in a tube going down a shallow borehole where the circulating gas is in contact with the soil gas phase via a gas permeable membrane. Above surface, moisture is removed from the gas stream before it reaches several gas sensors for CO2. Besides these, several other parameters are determined as well, e.g. soil moisture and soil temperature, water level, gas flow and gas moisture. In addition a meteorological station gives information about precipitation, air humidity, temperature and pressure, global radiation, wind direction and velocity in the area. Data are continuously collected by dataloggers at each station (5 minutes interval), transferred via GSM routers to the BGR server in Hannover and are stored in a specially designed database. The database does not only contain the measurements but also

  20. A New Automatic Subsurface Gas Monitoring System for Seismogeochemical Studies, Installed in Haruno Borehole, Shizuoka Prefecture, Central Japan

    NASA Astrophysics Data System (ADS)

    Miyakawa, Kazuya; Takama, Ruka; Kawabe, Iwao; Kariya, Shinnichi; Yamauchi, Tsuneo

    2010-12-01

    The results of subsurface gas monitoring by application of gas chromatography (GC) to the gas composition of bubbles associated with groundwater for seismogeochemical studies are reported. An automated gas monitoring system was used to determine gas compositions in a 500-m borehole at the Haruno Crustal Movement Observation Site (HOS), central Japan during period 1, from December 1999 to December 2000. The average ± two standard deviation (2SD) compositions of gases in this period were He = 82 ± 29 ppmV, H2 = 170 ± 62 ppmV, Ar = 0.05 ± 0.07%, N2 = 50 ± 8%, and CH4 = 45 ± 6%. A new automated gas monitoring system equipped with a micro-GC was installed in the borehole at the HOS, and gas bubbles from the borehole were monitored during period 2, from December 2006 to March 2007. The average ± two standard deviation (2SD) compositions of gases in this period were He = 8 ± 7 ppmV, H2 = 13 ± 15 ppmV, Ar = 0.6 ± 0.3%, N2 = 66 ± 7%, and CH4 = 14 ± 14%. The gas concentration ratios (He/Ar, H2/Ar, N2/Ar, and CH4/Ar) fluctuated significantly over time and repeatedly showed abrupt spike-like increases during period 2. The gas compositions obtained in period 1 and 2 were markedly different. Over the period from 2006 to 2007, the gas bubbles were depleted in He, H2, and CH4 of deep origin, but enriched in Ar and N2 of atmospheric origin. This difference can be interpreted as being due to an irreversible change of the aquifer/gas system. The present deep component in the HOS gas is estimated to have composition He = 63 ppmV, H2 = 37 ppmV, Ar = 0.17%, N2 = 63%, and CH4 = 37%. The new monitoring system is able to analyze the gas composition using a smaller volume of sample gas and with greater precision than the previous system. During the 3-month monitoring period 2, the separation capacity of the capillary column of the micro-GC was sufficiently maintained to determine gas-chromatographic peak areas for the five gaseous species examined. This study confirms that the