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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. 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...

  6. 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.

  7. 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.

  8. 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.

  9. 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.

  10. 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...

  11. 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)

  12. 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.

  13. 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.

  14. 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.

  15. 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.

  16. 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.

  17. 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.

  18. 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

  19. 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.

  20. 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.

  1. 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.

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

    Code of Federal Regulations, 2011 CFR

    2011-07-01

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

  3. 30 CFR 77.303 - Hot gas inlet chamber dropout doors.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

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

  4. 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.

  5. 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.

  6. 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.

  7. 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.

  8. Oxygen sensor for monitoring gas mixtures containing hydrocarbons

    DOEpatents

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

    1996-03-12

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

  9. 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.

  10. Gas House Autonomous System Monitoring

    NASA Technical Reports Server (NTRS)

    Miller, Luke; Edsall, Ashley

    2015-01-01

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

  11. 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.

  12. 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.

  13. 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.

  14. 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.

  15. Development of a Liquefied Noble Gas Time Projection Chamber

    NASA Astrophysics Data System (ADS)

    Lesser, Ezra; White, Aaron; Aidala, Christine

    2015-10-01

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

  16. 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.

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

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

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

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

  19. 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.

  20. A Novel Infrared Gas Monitor

    NASA Astrophysics Data System (ADS)

    Wang, Yingding; Zhong, Hongjie

    2000-03-01

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

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

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

  2. 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.

  3. 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.

  4. 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.

  5. 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.

  6. 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.

  7. 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.

  8. [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.

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

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

  10. 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.

  11. 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.

  12. 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.

  13. 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.

  14. 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)

  15. 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.

  16. 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.

  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. 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.

  19. 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.

  20. 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.

  1. 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

  2. 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.

  3. 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.

  4. 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.

  5. 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.

  6. 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.

  7. 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)

  8. 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

  9. 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.

  10. 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.

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

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

  12. 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.

  13. 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.

  14. 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.

  15. 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.

  16. 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.

  17. 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.

  18. 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.

  19. 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.

  20. 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.

  1. 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.

  2. 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.

  3. 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.

  4. 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

  5. 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.

  6. 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.

  7. 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.

  8. 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.

  9. 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.

  10. 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.

  11. 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.

  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 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.

  14. 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.

  15. 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.

  16. 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

  17. 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.

  18. 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.

  19. 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.

  20. 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.

  1. 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

  2. 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.

  3. 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.

  4. 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.

  5. 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.

  6. 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.

  7. 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.

  8. 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.

  9. 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

  10. 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.

  11. 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.

  12. 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.

  13. 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.

  14. Inherently safe passive gas monitoring system

    SciTech Connect

    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.

  15. 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.

  16. 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.

  17. 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.

  18. 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.

  19. 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

  20. 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.

  1. 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.

  2. 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.

  3. 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.

  4. 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.

  5. 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.

  6. 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.

  7. 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.

  8. 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.

  9. 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

  10. 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.

  11. 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.

  12. 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

  13. 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.

  14. 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.

  15. 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

  16. 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.

  17. 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.

  18. 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.

  19. 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.

  20. 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.

  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. 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

  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. 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.

  6. 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.

  7. 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.

  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. 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

  10. 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.

  11. 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.

  12. 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.

  13. 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.

  14. 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

  15. 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.

  16. 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.

  17. 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.

  18. 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.

  19. [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.

  20. 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.

  1. 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.

  2. 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).

  3. 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.

  4. 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.

  5. 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.

  6. 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.

  7. 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.

  8. 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.

  9. 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.

  10. Ionization chamber

    DOEpatents

    Walenta, Albert H.

    1981-01-01

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

  11. 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

  12. Operating experience review of an INL gas monitoring system

    SciTech Connect

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

    2015-03-12

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

  13. 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.

  14. 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.

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

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

  16. 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.

  17. 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.

  18. 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.

  19. 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.

  20. 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.

  1. 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.

  2. 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.

  3. 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

  4. 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.

  5. 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

  6. 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.

  7. 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.

  8. 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.

  9. 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.

  10. 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.

  11. 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.

  12. 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

  13. 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...

  14. 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...

  15. 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...

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

    Code of Federal Regulations, 2011 CFR

    2011-04-01

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

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

    Code of Federal Regulations, 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...

  18. 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.

  19. 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.

  20. 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.

  1. 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

  2. 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

  3. 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.

  4. 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.

  5. 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.

  6. 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.

  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. 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.

  9. 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.

  10. 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.

  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. 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.

  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. 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.

  15. 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

  16. 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.

  17. 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.

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

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

  19. 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.

  20. 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.

  1. 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

  2. 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.

  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. 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

  5. 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

  6. 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...

  7. 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.

  8. 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.

  9. Flow chamber

    SciTech Connect

    Morozov, Victor

    2011-01-18

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

  10. 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.

  11. 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

  12. 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.

  13. 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.

  14. 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.

  15. 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.

  16. 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.

  17. 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

  18. 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

  19. 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.

  20. 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.

  1. 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.

  2. 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.

  3. 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.

  4. 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.

  5. 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.

  6. 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.

  7. 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

  8. 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.

  9. 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

  10. 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

  11. 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.

  12. 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

  13. 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.

  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. 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.

  16. [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.

  17. 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.

  18. 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.

  19. 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.

  20. 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

  1. 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.

  2. 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

  3. 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.

  4. 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.

  5. 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

  6. 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.

  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. 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.

  9. 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.

  10. 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.

  11. 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

  12. 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.

  13. 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.

  14. 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.

  15. 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.

  16. 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.

  17. 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.

  18. 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.

  19. 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.

  20. 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.

  1. 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

  2. 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

  3. 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

  4. 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.

  5. 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.

  6. 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.

  7. 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.

  8. 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

  9. 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.

  10. 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).

  11. 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

  12. 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.

  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. 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

  15. 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)

  16. 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.

  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. 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.

  19. 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.

  20. 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.

  1. 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%.

  2. 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.

  3. 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.

  4. 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.

  5. 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.

  6. 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.

  7. 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.

  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. 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.

  10. 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

  11. 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.

  12. 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.

  13. 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.

  14. 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.

  15. 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.

  16. 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.

  17. 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.

  18. 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...

  19. 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.

  20. 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.

  1. 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.

  2. 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.

  3. 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

  4. 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.

  5. 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.

  6. 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.

  7. 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.

  8. 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.

  9. 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

  10. 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

  11. 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.

  12. 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.

  13. 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.'

  14. 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).

  15. 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.

  16. 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.

  17. 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.

  18. 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.

  19. 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.

  20. 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.

  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. 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

  5. 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

  6. 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

  7. 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).

  8. 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.

  9. 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

  10. Prediction of back-scatter radiations to a beam monitor chamber of medical linear accelerators by use of the digitized target-current-pulse analysis method.

    PubMed

    Suzuki, Yusuke; Hayashi, Naoki; Kato, Hideki; Fukuma, Hiroshi; Hirose, Yasujiro; Kawano, Makoto; Nishii, Yoshio; Nakamura, Masaru; Mukouyama, Takashi

    2013-01-01

    In small-field irradiation, the back-scattered radiation (BSR) affects the counts measured with a beam monitor chamber (BMC). In general, the effect of the BSR depends on the opened-jaw size. The effect is significantly large in small-field irradiation. Our purpose in this study was to predict the effect of BSR on LINAC output accurately with an improved target-current-pulse (TCP) technique. The pulse signals were measured with a system consisting of a personal computer and a digitizer. The pulse signals were analyzed with in-house software. The measured parameters were the number of pulses, the change in the waveform and the integrated signal values of the TCPs. The TCPs were measured for various field sizes with four linear accelerators. For comparison, Yu's method in which a universal counter was used was re-examined. The results showed that the variance of the measurements by the new method was reduced to approximately 1/10 of the variance by the previous method. There was no significant variation in the number of pulses due to a change in the field size in the Varian Clinac series. However, a change in the integrated signal value was observed. This tendency was different from the result of other investigations in the past. Our prediction method is able to define the cutoff voltage for the TCP acquired by digitizer. This functionality provides the capability of clearly classifying TCPs into signals and noise. In conclusion, our TCP analysis method can predict the effect of BSR on the BMC even for small-field irradiations.

  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. 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.

  14. CHAMBERS FERRY ROADLESS AREA, TEXAS.

    USGS Publications Warehouse

    Houser, B.B.; Ryan, George S.

    1984-01-01

    A geologic and geochemical investigation of the Chambers Ferry Roadless Area, Texas was conducted. The area has probable mineral-resource potential for oil and gas and for lignite. No metallic or additional energy resources were identified in the investigation. Detailed analyses of well logs from the vicinity of the Chambers Ferry Roadless Area, in conjunction with seismic data, are necessary to determine if the subsurface stratigraphy and structure are favorable for the accumulation of oil and gas. A shallow drilling program involving coring on a close-space grid is necessary for determination of the rank and continuity of seams of lignitic sediments in the area.

  15. Vapor concentration monitor

    DOEpatents

    Bayly, John G.; Booth, Ronald J.

    1977-01-01

    An apparatus for monitoring the concentration of a vapor, such as heavy water, having at least one narrow bandwidth in its absorption spectrum, in a sample gas such as air. The air is drawn into a chamber in which the vapor content is measured by means of its radiation absorption spectrum. High sensitivity is obtained by modulating the wavelength at a relatively high frequency without changing its optical path, while high stability against zero drift is obtained by the low frequency interchange of the sample gas to be monitored and of a reference sample. The variable HDO background due to natural humidity is automatically corrected.

  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. Design and Fabrication of A Modern Radon-Tight Chamber for Radon Concentration Measurements

    NASA Astrophysics Data System (ADS)

    Alhalemi, Ahmed; Jaafar, M. S.

    2010-07-01

    A modern radon-tight chamber (RTC) has been designed and fabricated to meet the request and requirements for both the Professional Continuous Radon Monitor (PCRM), and the RAD7 radon detector. The chamber is cubic shaped, made of Perspex with a volume of about 0.125 m3. The RTC was also equipped with a thermometer and a humidity sensor. A pair of gloves was attached on one side of the chamber's lateral opening for operating the PCRM. In addition, a fan was installed to circulate the air, and to distribute the radon gas to ensure homogeneity after the air inside the chamber is evacuated with nitrogen gas. At the end of the monitoring period, the results of the concentration of the radon emanated from a sample placed inside the chamber will then be available in any of three forms: numerical display on the control panel of the radon detector, printed report on the accessory printer, or transferred into a file on a personal computer via the RS-232 Serial port without disturbing the radon concentration inside the chamber. Computer software is provided by the manufacturer for this purpose. The result of analysis was presented in a one-way ANOVA that indicated that the radon concentration means are not difference for the three different positions of the PCRM (P > 0.05). Thus, this RTC can be used to measure the radon concentration and its progeny; in addition, it can be used for research and useful studies on radon exhalation from building materials.

  20. Idaho National Laboratory (INL) Site Greenhouse Gas (GHG) Monitoring Plan - 40 CFR 98

    SciTech Connect

    Deborah L. Layton; Kimberly Frerichs

    2010-07-01

    The purpose of this Greenhouse Gas (GHG) Monitoring Plan is to meet the monitoring plan requirements of Title 40 of the Code of Federal Regulations Part 98.3(g)(5). This GHG Monitoring Plan identifies procedures and methodologies used at the Idaho National Laboratory Site (INL Site) to collect data used for GHG emissions calculations and reporting requirements from stationary combustion and other regulated sources in accordance with 40 CFR 98, Subparts A and other applicable subparts. INL Site Contractors determined subpart applicability through the use of a checklist (Appendix A). Each facility/contractor reviews operations to determine which subparts are applicable and the results are compiled to determine which subparts are applicable to the INL Site. This plan is applicable to the 40 CFR 98-regulated activities managed by the INL Site contractors: Idaho National Laboratory (INL), Idaho Cleanup Project (ICP), Advanced Mixed Waste Treatment Project (AMWTP), and Naval Reactors Facilities (NRF).

  1. Idaho National Laboratory (INL) Site Greenhouse Gas (GHG) Monitoring Plan - 40 CFR 98

    SciTech Connect

    Deborah L. Layton; Kimberly Frerichs

    2011-12-01

    The purpose of this Greenhouse Gas (GHG) Monitoring Plan is to meet the monitoring plan requirements of Title 40 of the Code of Federal Regulations Part 98.3(g)(5). This GHG Monitoring Plan identifies procedures and methodologies used at the Idaho National Laboratory Site (INL Site) to collect data used for GHG emissions calculations and reporting requirements from stationary combustion and other regulated sources in accordance with 40 CFR 98, Subparts A and other applicable subparts. INL Site Contractors determined subpart applicability through the use of a checklist (Appendix A). Each facility/contractor reviews operations to determine which subparts are applicable and the results are compiled to determine which subparts are applicable to the INL Site. This plan is applicable to the 40 CFR 98-regulated activities managed by the INL Site contractors: Idaho National Laboratory (INL), Idaho Cleanup Project (ICP), Advanced Mixed Waste Treatment Project (AMWTP), and Naval Reactors Facilities (NRF).

  2. 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

  3. 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

  4. Application of thoron interference as a tool for simultaneous measurement of radon and thoron with a pulse ionisation chamber.

    PubMed

    Tripathi, R M; Sumesh, C G; Vinod Kumar, A; Puranik, V D

    2013-07-01

    Pulse ionisation chamber (PIC)-based monitors measuring radioactive gas radon ((222)Rn) without energy discrimination will have interference due to thoron ((220)Rn) present in the atmosphere. A technique has been developed to use this property of interference for simultaneous measurement of radon and thoron gas. These monitors work on the principle of counting of gross alphas emitted from radon and its progeny. A theoretical model has been developed for the variation of thoron sensitivity with respect to the flow rate of gas through the monitor. The thoron sensitivity of the monitor is found to vary with the flow rate of gas through the monitor. Using this sensitivity, the sampling procedure has been developed and verified for simultaneous measurement of radon and thoron. The PIC-measured radon and thoron concentration using this procedure agrees well with those measured by using standard radon and thoron discriminating monitor.

  5. Monitoring induced seismicity from underground gas storage: first steps in Italy

    NASA Astrophysics Data System (ADS)

    Mucciarelli, Marco; Priolo, Enrico

    2013-04-01

    The supply of natural gas and its storage are focal points of the Italian politics of energy production and will have increasing importance in the coming years. About a dozen reservoirs are currently in use and fifteen are in development or awaiting approval. Some of these are found in the vicinity of geological structures that are seismically active. The assessment of seismic hazard (both for natural background and induced seismicity) for a geological gas storage facility has a number of unconventional aspects that must be recognized and traced in a clear, ordered way and using guidelines and rules that leave less room as possible for interpretation by the individual applicant / verification body. Similarly, for control and monitoring there are not clearly defined procedures or standard instrumentation, let alone tools for analysing and processing data. Finally, governmental organizations in charge of permission grants and operative control tend to have appropriate scientific knowledge only in certain areas and not in others (e.g. the seismic one), and the establishment of an independent multidisciplinary inspection body appears desirable. The project StoHaz (https://sites.google.com/site/s2stohaz/home) aims to initiate a series of actions to overcome these deficiencies and allow to define procedures and standards for the seismic hazard assessment and control of the activities of natural gas storage in underground reservoirs. OGS will take advantage of the experience gained with the design, installation and maintenance of the seismic network monitoring the Collalto reservoir, at the moment the only example in Italy of a public research institution monitoring independently the activities of a private gas storage company.

  6. Results of a Long-Term Demonstration of an Optical Multi-Gas Monitor on ISS

    NASA Technical Reports Server (NTRS)

    Mudgett, Paul; Pilgrim, Jeffrey S.

    2015-01-01

    Previously at SAMAP we reported on the development of tunable diode laser spectroscopy (TDLS) based instruments for measuring small gas molecules in real time. TDLS technology has matured rapidly over the last 5 years as a result of advances in low power diode lasers as well as better detection schemes. In collaboration with two small businesses Vista Photonics, Inc. and Nanoracks LLC, NASA developed a 4 gas TDLS based monitor for an experimental demonstration of the technology on the International Space Station (ISS). Vista invented and constructed the core TDLS sensor. Nanoracks designed and built the enclosure, and certified the integrated monitor as a payload. The device, which measures oxygen, carbon dioxide, ammonia and water vapor, is called the Multi-Gas Monitor (MGM). MGM measures the 4 gases every few seconds and records a 30 second moving average of the concentrations. The relatively small unit draws only 2.5W. MGM was calibrated at NASA-Johnson Space Center in July 2013 and launched to ISS on a Soyuz vehicle in November 2013. Installation and activation of MGM occurred in February 2014, and the unit has been operating nearly continuously ever since in the Japanese Experiment Module. Data is downlinked from ISS about once per week. Oxygen and carbon dioxide data is compared with that from the central Major Constituents Analyzer. Water vapor data is compared with dew point measurements made by sensors in the Columbus module. The ammonia channel was tested by the crew using a commercial ammonia inhalant. MGM is remarkably stable to date. Results of 18 months of operation are presented and future applications including combustion product monitoring are discussed.

  7. Plasma chemistry in wire chambers

    SciTech Connect

    Wise, J.

    1990-05-01

    The phenomenology of wire chamber aging is discussed and fundamentals of proportional counters are presented. Free-radical polymerization and plasma polymerization are discussed. The chemistry of wire aging is reviewed. Similarities between wire chamber plasma (>1 atm dc-discharge) and low-pressure rf-discharge plasmas, which have been more widely studied, are suggested. Construction and use of a system to allow study of the plasma reactions occurring in wire chambers is reported. A proportional tube irradiated by an {sup 55}Fe source is used as a model wire chamber. Condensable species in the proportional tube effluent are concentrated in a cryotrap and analyzed by gas chromatography/mass spectrometry. Several different wire chamber gases (methane, argon/methane, ethane, argon/ethane, propane, argon/isobutane) are tested and their reaction products qualitatively identified. For all gases tested except those containing methane, use of hygroscopic filters to remove trace water and oxygen contaminants from the gas resulted in an increase in the average molecular weight of the products, consistent with results from low-pressure rf-discharge plasmas. It is suggested that because water and oxygen inhibit polymer growth in the gas phase that they may also reduce polymer deposition in proportional tubes and therefore retard wire aging processes. Mechanistic implications of the plasma reactions of hydrocarbons with oxygen are suggested. Unresolved issues in this work and proposals for further study are discussed.

  8. Cyclically controlled welding purge chamber

    NASA Technical Reports Server (NTRS)

    Gallagher, Robert L. (Inventor)

    1996-01-01

    An arrangement for butt-welding cylindrical sections of large, thin-wall tanks includes a rotatable mandrel with side-by-side sets of radial position adjusters. Each set of adjusters bears on one of the tank sections adjacent the seam, to prevent the sections from sagging out-of-round. The mandrel rotates relative to the welder, so that a continuous seam is formed. A purge chamber is fixed in position behind the seam at the weld head, and is flushed with inert gas. The purge chamber includes a two-sided structure which is contiguous with the cylindrical sections and a circumferential vane to form an open-ended tube-like structure, through which the radial position adjusters pass as the mandrel and cylindrical workpiece sections rotate. The tube-like structure is formed into a chamber by a plurality of movable gates which are controlled to maintain a seal while allowing adjusters to progress through the purge chamber.

  9. On0Line Fuel Failure Monitor for Fuel Testing and Monitoring of Gas Cooled Very High Temperature Reactor

    SciTech Connect

    Ayman I. Hawari; Mohamed A. Bourham

    2010-04-22

    IVery High Temperature Reactors (VHTR) utilize the TRISO microsphere as the fundamental fuel unit in the core. The TRISO microsphere (~ 1- mm diameter) is composed of a UO2 kernel surrounded by a porous pyrolytic graphite buffer, an inner pyrolytic graphite layer, a silicon carbide (SiC) coating, and an outer pyrolytic graphite layer. The U-235 enrichment of the fuel is expected to range from 4% – 10% (higher enrichments are also being considered). The layer/coating system that surrounds the UO2 kernel acts as the containment and main barrier against the environmental release of radioactivity. To understand better the behavior of this fuel under in-core conditions (e.g., high temperature, intense fast neutron flux, etc.), the US Department of Energy (DOE) is launching a fuel testing program that will take place at the Advanced Test Reactor (ATR) located at Idaho National Laboratory (INL). During this project North Carolina State University (NCSU) researchers will collaborate with INL staff for establishing an optimized system for fuel monitoring for the ATR tests. In addition, it is expected that the developed system and methods will be of general use for fuel failure monitoring in gas cooled VHTRs.

  10. Gas injected vacuum switch

    DOEpatents

    Hardin, K. Dan

    1977-01-01

    The disclosure relates to a gas injected vacuum switch comprising a housing having an interior chamber, a conduit for evacuating the interior chamber, within the chamber an anode and a cathode spaced from the anode, and a detonator for injecting electrically conductive gas into the chamber between the anode and the cathode to provide a current path therebetween.

  11. Bird interactions with offshore oil and gas platforms: review of impacts and monitoring techniques.

    PubMed

    Ronconi, Robert A; Allard, Karel A; Taylor, Philip D

    2015-01-01

    Thousands of oil and gas platforms are currently operating in offshore waters globally, and this industry is expected to expand in coming decades. Although the potential environmental impacts of offshore oil and gas activities are widely recognized, there is limited understanding of their impacts on migratory and resident birds. A literature review identified 24 studies and reports of bird-platform interactions, most being qualitative and half having been peer-reviewed. The most frequently observed effect, for seabirds and landbirds, is attraction and sometimes collisions associated with lights and flares; episodic events have caused the deaths of hundreds or even thousands of birds. Though typically unpredictable, anecdotally, it is known that poor weather, such as fog, precipitation and low cloud cover, can exacerbate the effect of nocturnal attraction to lights, especially when coincidental with bird migrations. Other effects include provision of foraging and roosting opportunities, increased exposure to oil and hazardous environments, increased exposure to predators, or repulsion from feeding sites. Current approaches to monitoring birds at offshore platforms have focused on observer-based methods which can offer species-level bird identification, quantify seasonal patterns of relative abundance and distribution, and document avian mortality events and underlying factors. Observer-based monitoring is time-intensive, limited in spatial and temporal coverage, and suffers without clear protocols and when not conducted by trained, independent observers. These difficulties are exacerbated because deleterious bird-platform interaction is episodic and likely requires the coincidence of multiple factors (e.g., darkness, cloud, fog, rain conditions, occurrence of birds in vicinity). Collectively, these considerations suggest a need to implement supplemental systems for monitoring bird activities around offshore platforms. Instrument-based approaches, such as radar

  12. Total Dissolved Gas Monitoring in Chum Salmon Spawning Gravels Below Bonneville Dam

    SciTech Connect

    Arntzen, Evan V.; Geist, David R.; Panther, Jennifer L.; Dawley, Earl

    2007-01-30

    At the request of the U.S. Army Corps of Engineers (Portland District), Pacific Northwest National Laboratory (PNNL) conducted research to determine whether total dissolved gas concentrations are elevated in chum salmon redds during spring spill operations at Bonneville Dam. The study involved monitoring the total dissolved gas levels at egg pocket depth and in the river at two chum salmon spawning locations downstream from Bonneville Dam. Dissolved atmospheric gas supersaturation generated by spill from Bonneville Dam may diminish survival of chum (Oncorhynchus keta) salmon when sac fry are still present in the gravel downstream from Bonneville Dam. However, no previous work has been conducted to determine whether total dissolved gas (TDG) levels are elevated during spring spill operations within incubation habitats. The guidance used by hydropower system managers to provide protection for pre-emergent chum salmon fry has been to limit TDG to 105% after allowing for depth compensation. A previous literature review completed in early 2006 shows that TDG levels as low as 103% have been documented to cause mortality in sac fry. Our study measured TDG in the incubation environment to evaluate whether these levels were exceeded during spring spill operations. Total dissolved gas levels were measured within chum salmon spawning areas near Ives Island and Multnomah Falls on the Columbia River. Water quality sensors screened at egg pocket depth and to the river were installed at both sites. At each location, we also measured dissolved oxygen, temperature, specific conductance, and water depth to assist with the interpretation of TDG results. Total dissolved gas was depth-compensated to determine when levels were high enough to potentially affect sac fry. This report provides detailed descriptions of the two study sites downstream of Bonneville Dam, as well as the equipment and procedures employed to monitor the TDG levels at the study sites. Results of the monitoring at

  13. Electrothermal Vaporization Sample Introduction for Spaceflight Water Quality Monitoring via Gas Chromatography-Differential Mobility Spectrometry.

    PubMed

    Wallace, William T; Gazda, Daniel B; Limero, Thomas F; Minton, John M; Macatangay, Ariel V; Dwivedi, Prabha; Fernández, Facundo M

    2015-06-16

    In the history of manned spaceflight, environmental monitoring has relied heavily on archival sampling. However, with the construction of the International Space Station (ISS) and the subsequent extension in mission duration up to one year, an enhanced, real-time method for environmental monitoring is necessary. The station air is currently monitored for trace volatile organic compounds (VOCs) using gas chromatography-differential mobility spectrometry (GC-DMS) via the Air Quality Monitor (AQM), while water is analyzed to measure total organic carbon and biocide concentrations using the Total Organic Carbon Analyzer (TOCA) and the Colorimetric Water Quality Monitoring Kit (CWQMK), respectively. As mission scenarios extend beyond low Earth orbit, a convergence in analytical instrumentation to analyze both air and water samples is highly desirable. Since the AQM currently provides quantitative, compound-specific information for air samples and many of the targets in air are also common to water, this platform is a logical starting point for developing a multimatrix monitor. Here, we report on the interfacing of an electrothermal vaporization (ETV) sample introduction unit with a ground-based AQM for monitoring target analytes in water. The results show that each of the compounds tested from water have similar GC-DMS parameters as the compounds tested in air. Moreover, the ETV enabled AQM detection of dimethlsilanediol (DMSD), a compound whose analysis had proven challenging using other sample introduction methods. Analysis of authentic ISS water samples using the ETV-AQM showed that DMSD could be successfully quantified, while the concentrations obtained for the other compounds also agreed well with laboratory results.

  14. Promoted-Combustion Chamber with Induction Heating Coil

    NASA Technical Reports Server (NTRS)

    Richardson, Erin; Hagood, Richard; Lowery, Freida; Herald, Stephen

    2006-01-01

    prevent heating of the base of the chamber during use. A sapphire cylinder protects the coil against slag generated during an experiment. The induction coil is energized by a 6-kW water-cooled power supply operating at a frequency of 400 kHz. The induction coil is part of a parallel-tuned circuit, the tuning of which is used to adjust the coupling of power to the specimen. The chamber is mounted on a test stand along with pumps, valves, and plumbing for transferring pressurized gas into and out of the chamber. In addition to multiple video cameras aimed through the windows encircling the chamber, the chamber is instrumented with gauges for monitoring the progress of an experiment. One of the gauges is a dual-frequency infrared temperature transducer aimed at the specimen through one window. Chamber operation is achieved via a console that contains a computer running apparatus-specific software, a video recorder, and real-time video monitors. For safety, a blast wall separates the console from the test stand.

  15. Biochemical gas sensor (bio-sniffer) for ultrahigh-sensitive gaseous formaldehyde monitoring.

    PubMed

    Kudo, Hiroyuki; Suzuki, Yuki; Gessei, Tomoko; Takahashi, Daishi; Arakawa, Takahiro; Mitsubayashi, Kohji

    2010-10-15

    An ultrahigh-sensitive fiber-optic biochemical gas sensor (bio-sniffer) for continuous monitoring of indoor formaldehyde was constructed and tested. The bio-sniffer measures gaseous formaldehyde as fluorescence of nicotinamide adenine dinucleotide (NADH), which is the product of formaldehyde dehydrogenase (FALDH) reaction. The bio-sniffer device was constructed by attaching a flow cell with a FALDH immobilized membrane onto a fiber-optic NADH measurement system. The NADH measurement system utilizes an ultraviolet-light emitting diode (UV-LED) with peak emission of 335 nm as an excitation light source. The excitation light was introduced to an optical fiber probe, and fluorescence emission of neighboring NADH, which was produced by applying formaldehyde vapor to the FALDH membrane, was concentrically measured with a photomultiplier tube. Assessment of the bio-sniffer was carried out using a standard gas generator. Response, calibration range and selectivity to other chemical substances were investigated. Circulating phosphate buffer, which contained NAD+, available for continuous monitoring of formaldehyde vapor. The calibration range of the bio-sniffer was 2.5 ppb to 10 ppm, which covers the guideline value of the World Health Organization (80 ppb). High selectivity to other gaseous substances due to specific activity of FALDH was also confirmed. Considering its high sensitivity, a possible application of the bio-sniffer is continuous indoor formaldehyde monitoring to provide healthy residential atmosphere.

  16. Physics Simulation Software for Autonomous Propellant Loading and Gas House Autonomous System Monitoring

    NASA Technical Reports Server (NTRS)

    Regalado Reyes, Bjorn Constant

    2015-01-01

    1. Kennedy Space Center (KSC) is developing a mobile launching system with autonomous propellant loading capabilities for liquid-fueled rockets. An autonomous system will be responsible for monitoring and controlling the storage, loading and transferring of cryogenic propellants. The Physics Simulation Software will reproduce the sensor data seen during the delivery of cryogenic fluids including valve positions, pressures, temperatures and flow rates. The simulator will provide insight into the functionality of the propellant systems and demonstrate the effects of potential faults. This will provide verification of the communications protocols and the autonomous system control. 2. The High Pressure Gas Facility (HPGF) stores and distributes hydrogen, nitrogen, helium and high pressure air. The hydrogen and nitrogen are stored in cryogenic liquid state. The cryogenic fluids pose several hazards to operators and the storage and transfer equipment. Constant monitoring of pressures, temperatures and flow rates are required in order to maintain the safety of personnel and equipment during the handling and storage of these commodities. The Gas House Autonomous System Monitoring software will be responsible for constantly observing and recording sensor data, identifying and predicting faults and relaying hazard and operational information to the operators.

  17. Application of geoelectric methods for man-caused gas deposit mapping and monitoring

    NASA Astrophysics Data System (ADS)

    Yakymchuk, M. A.; Levashov, S. P.; Korchagin, I. N.; Syniuk, B. B.

    2009-04-01

    anomaly total area made S=20.7 hectares on 07.10.08, and S=19.7 hectares on 13.10.08 and S=10.5 hectares on 08.11.08. The anomaly intensity has decreased, some local extremum has appeared. All this testifies that there is an intensive degassing process of cross-section upper part through producing wells and the drilled degassing wells. Exclusively important feature of the FSPEF-VERS technology is an operationability(!) the of practical problems solving. For an emergency situation on gas field an operationability of technology has crucial importance. For one day of works only the field staff management has received considerable volume of operative information, allowing in quite proved manner to estimate as accident scales and it possible reasons, and so those threats, which this accident can represent for nearby located settlements. So, the imposing of a sketch-map of distribution of a "man-caused" gas deposit on a map of wells location has shown that this deposit does not extend over field border and, hence, does not represent essential threat for nearby settlements. Technology operationability in a whole and practical experience of repeated measurements testifies about possibility of the FSPEF-VERS methods using for operative carrying out of monitoring character survey. Such monitoring survey can be spent on a field after degassing wells drilling to check the process of gas pump-down from a "man-caused" deposit. Geoelectric researches on an emergency site of field on 08.11.08 and the received thus results practically show efficiency and working capacity of the FSPEF-VERS technology in a monitoring mode. The performed experimental works have shown, that process of gas pump-down from a "man-caused" deposit can be traced in time by the FSPEF-VERS technology. It is expedient to locate the additional degassing wells for definitive elimination of accident consequences with taking into account the data of monitoring works by FSPEF-VERS methods. The experiment results testify of

  18. Fiber optic sensing system for temperature and gas monitoring in coal waste pile combustion environments

    NASA Astrophysics Data System (ADS)

    Viveiros, D.; Ribeiro, J.; Ferreira, J.; Lopez-Albada, A.; Pinto, A. M. R.; Perez-Herrera, R. A.; Diaz, S.; Lopez-Gil, A.; Dominguez-Lopez, A.; Esteban, O.; Martin-Lopez, S.; Auguste, J.-L.; Jamier, R.; Rougier, S.; Silva, S. O.; Frazão, O.; Santos, J. L.; Flores, D.; Roy, P.; Gonzalez-Herraez, M.; Lopez-Amo, M.; Baptista, J. M.

    2015-09-01

    It is presented an optical fiber sensing system projected to operate in the demanding conditions associated with coal waste piles in combustion. Distributed temperature measurement and spot gas sensing are requirements for such a system. A field prototype has been installed and is continuously gathering data, which will input a geological model of the coal waste piles in combustion aiming to understand their dynamics and evolution. Results are presented on distributed temperature and ammonia measurement, being noticed any significant methane emission in the short time period considered. Carbon dioxide is also a targeted gas for measurement, with validated results available soon. The assessment of this technology as an effective and reliable tool to address the problem of monitoring coal waste piles in combustion opens the possibility of its widespread application in view of the worldwide presence of coal related fires.

  19. Testing of a prototype of calibration facility for noble gas monitoring using 41Ar.

    PubMed

    Saibathulham, Holnisar; Wurdiyanto, Gatot; Marsum, Pujadi

    2012-09-01

    A prototype of a calibration facility for noble gas monitoring using (41)Ar in the PTKMR-BATAN has been tested. The facility was designed in such a way that the standard source of gas can be reused. The radioactive (41)Ar source was obtained by thermal neutron reaction of (40)Ar(n, γ)(41)Ar using a thermal neutron flux of 4.8×10(13) neutrons per cm(2) per second in two minutes on the multipurpose G.A. Siwabessy Reactor (Batan, Serpong, Indonesia). Gamma spectrometry was used to measure the radioactivity and purity of (41)Ar. The spectrum of the (41)Ar observed yields an energy of 1294 keV because of the highest intensity (99.2%). The activity of (41)Ar was 2821 kBq and 4% of the expanded uncertainty. The time required for (41)Ar to reach homogeneity was 7 min, and the effectiveness of resuse was 53%.

  20. Neutron-chamber detectors and applications

    SciTech Connect

    Fehlau, P.E.; Atwater, H.F.; Coop, K.L.

    1990-01-01

    Detector applications in Nuclear Safeguards and Waste Management have included measuring neutrons from fission and (alpha,n) reactions with well-moderated neutron proportional counters, often embedded in a slab of polyethylene. Other less-moderated geometries are useful for detecting both bare and moderated fission-source neutrons with good efficiency. The neutron chamber is an undermoderated detector design comprising a large, hollow, polyethylene-walled chamber containing one or more proportional counters. Neutron-chamber detectors are relatively inexpensive; can have large apertures, usually through a thin chamber wall; and offer very good detection efficiency per dollar. Neutron-chamber detectors have also been used for monitoring vehicles and for assaying large crates of transuranic waste. Our Monte Carlo calculations for a new application (monitoring low-density waste for concealed plutonium) illustrate the advantages of the hollow-chamber design for detecting moderated fission sources. 9 refs., 6 figs., 2 tabs.

  1. Chamber Clearing First Principles Modeling

    SciTech Connect

    Loosmore, G

    2009-06-09

    LIFE fusion is designed to generate 37.5 MJ of energy per shot, at 13.3 Hz, for a total average fusion power of 500 MW. The energy from each shot is partitioned among neutrons ({approx}78%), x-rays ({approx}12%), and ions ({approx}10%). First wall heating is dominated by x-rays and debris because the neutron mean free path is much longer than the wall thickness. Ion implantation in the first wall also causes damage such as blistering if not prevented. To moderate the peak-pulse heating, the LIFE fusion chamber is filled with a gas (such as xenon) to reduce the peak-pulse heat load. The debris ions and majority of the x-rays stop in the gas, which re-radiates this energy over a longer timescale (allowing time for heat conduction to cool the first wall sufficiently to avoid damage). After a shot, because of the x-ray and ion deposition, the chamber fill gas is hot and turbulent and contains debris ions. The debris needs to be removed. The ions increase the gas density, may cluster or form aerosols, and can interfere with the propagation of the laser beams to the target for the next shot. Moreover, the tritium and high-Z hohlraum debris needs to be recovered for reuse. Additionally, the cryogenic target needs to survive transport through the gas mixture to the chamber center. Hence, it will be necessary to clear the chamber of the hot contaminated gas mixture and refill it with a cool, clean gas between shots. The refilling process may create density gradients that could interfere with beam propagation, so the fluid dynamics must be studied carefully. This paper describes an analytic modeling effort to study the clearing and refilling process for the LIFE fusion chamber. The models used here are derived from first principles and balances of mass and energy, with the intent of providing a first estimate of clearing rates, clearing times, fractional removal of ions, equilibrated chamber temperatures, and equilibrated ion concentrations for the chamber. These can be used

  2. Remote sensing for gas plume monitoring using state-of-the-art infrared hyperspectral imaging

    NASA Astrophysics Data System (ADS)

    Hinnrichs, Michele

    1999-02-01

    Under contract to the US Air Force and Navy, Pacific Advanced Technology has developed a very sensitive hyperspectral imaging infrared camera that can perform remote imaging spectro-radiometry. One of the most exciting applications for this technology is in the remote monitoring of gas plume emissions. Pacific Advanced Technology (PAT) currently has the technology available to detect and identify chemical species in gas plumes using a small light weight infrared camera the size of a camcorder. Using this technology as a remote sensor can give advanced warning of hazardous chemical vapors undetectable by the human eye as well as monitor the species concentrations in a gas plume from smoke stack and fugitive leaks. Some of the gas plumes that have been measured and species detected using an IMSS imaging spectrometer are refinery smoke stacks plumes with emission of CO2, CO, SO2, NOx. Low concentration vapor unseen by the human eye that has been imaged and measured is acetone vapor evaporating at room temperature. The PAT hyperspectral imaging sensor is called 'Image Multi-spectral Sensing or IMSS.' The IMSS instrument uses defractive optic technology and exploits the chromatic aberrations of such lenses. Using diffractive optics for both imaging and dispersion allows for a very low cost light weight robust imaging spectrometer. PAT has developed imaging spectrometers that span the spectral range from the visible, midwave infrared (3 to 5 microns) and longwave infrared (8 to 12 microns) with this technology. This paper will present the imaging spectral data that we have collected on various targets with our hyperspectral imaging instruments as will also describe the IMSS approach to imaging spectroscopy.

  3. On-line combustion monitoring on dry low NOx industrial gas turbines

    NASA Astrophysics Data System (ADS)

    Rea, S.; James, S.; Goy, C.; Colechin, M. J. F.

    2003-07-01

    To reduce the NOx emissions levels produced by industrial gas turbines most manufacturers have adopted a lean premixed approach to combustion. Such combustion systems are susceptible to combustion-driven oscillations, and much of the installed modern gas turbines continue to suffer from reduced reliability due to instability-related problems. The market conditions which now exist under the New Electricity Trading Arrangements provide a strong driver for power producers to improve the reliability and availability of their generating units. With respect to low-emission gas turbines, such improvements can best be achieved through a combination of sophisticated monitoring, combustion optimization and, where appropriate, plant modifications to reduce component failure rates. On-line combustion monitoring (OLCM) provides a vital contribution to each of these by providing the operator with increased confidence in the health of the combustion system and also by warning of the onset of combustion component deterioration which could cause significant downstream damage. The OLCM systems installed on Powergen's combined cycle gas turbine plant utilize high-temperature dynamic pressure transducers mounted close to the combustor to enable measurement of the fluctuating pressures experienced within the combustion system. Following overhaul, a reference data set is determined over a range of operating conditions. Real-time averaged frequency spectra are then compared to the reference data set to enable identification of abnormalities. Variations in the signal may occur due to changes in ambient conditions, fuel composition, operating conditions, and the onset of component damage. The systems on Powergen's plant have been used successfully to detect each of the above, examples of which are presented here.

  4. Gas analyzer for continuous monitoring of trace level methanethiol by microchannel collection and fluorescence detection.

    PubMed

    Toda, Kei; Kuwahara, Haruka; Kajiwara, Hidetaka; Hirota, Kazutoshi; Ohira, Shin-Ichi

    2014-09-02

    The highly odorous compound methanethiol, CH3SH, is commonly produced in biodegradation of biomass and industrial processes, and is classed as 2000 times more odorous than NH3. However, there is no simple analytical method for detecting low parts-per-billion in volume ratio (ppbv) levels of CH3SH. In this study, a micro gas analysis system (μGAS) was developed for continuous or near real time measurement of CH3SH at ppbv levels. In addition to a commercial fluorescence detector, a miniature high sensitivity fluorescence detector was developed using a novel micro-photomultiplier tube device. CH3SH was collected by absorption into an alkaline solution in a honeycomb-patterned microchannel scrubber and then mixed with the fluorescent reagent, 4-(N,N-dimethylaminosulfonyl)-7-fluoro-2,1,3-benzoxadiazole (DBD-F). Gaseous CH3SH was measured without serious interference from other sulfur compounds or amines. The limits of detection were 0.2ppbv with the commercial detector and 0.3ppbv with the miniature detector. CH3SH produced from a pulping process was monitored with the μGAS system and the data agreed well with those obtained by collection with a silica gel tube followed by thermal desorption-gas chromatography-mass spectrometry. The portable system with the miniature fluorescence detector was used to monitor CH3SH levels in near-real time in a stockyard and it was shown that the major odor component, CH3SH, presented and its concentration varied dynamically with time.

  5. Development of an improved GTA (gas tungsten arc) weld temperature monitor fixture

    SciTech Connect

    Hollar, D.L.

    1990-05-01

    An initial design weld temperature control fixture was implemented into final closure of an electronic assembly in November 1986. Use of this fixture indicated several areas that could be improved. Review of these areas with the process engineer and the weld operator provided the ideas to be incorporated into the new design Phase 2 fixture. Some primary areas of change and improvement included fixture mobility to provide better accessibility to the weld joint area, automatic timed blow cooling of the weld joint, and a feature to assure proper thermocouple placement. The resulting Phase 2 fixture design provided all of the essential weld temperature monitoring features in addition to several significant improvements. Technology developed during this project will pave the way to similar process monitoring of other manual gas tungsten arc (GTA) welding applications. 9 figs.

  6. GULF OF MEXICO SEAFLOOR STABILITY AND GAS HYDRATE MONITORING STATION PROJECT

    SciTech Connect

    J. Robert Woolsey; Thomas M. McGee; Robin C. Buchannon

    2004-11-01

    The gas hydrates research Consortium (HRC), established and administered at the University if Mississippi's Center for Marine Research and Environmental Technology (CMRET) has been active on many fronts in FY 03. Extension of the original contract through March 2004, has allowed completion of many projects that were incomplete at the end of the original project period due, primarily, to severe weather and difficulties in rescheduling test cruises. The primary objective of the Consortium, to design and emplace a remote sea floor station for the monitoring of gas hydrates in the Gulf of Mexico by the year 2005 remains intact. However, the possibility of levering HRC research off of the Joint Industries Program (JIP) became a possibility that has demanded reevaluation of some of the fundamental assumptions of the station format. These provisions are discussed in Appendix A. Landmark achievements of FY03 include: (1) Continuation of Consortium development with new researchers and additional areas of research contribution being incorporated into the project. During this period, NOAA's National Undersea Research Program's (NURP) National Institute for Undersea Science and Technology (NIUST) became a Consortium funding partner, joining DOE and Minerals Management Service (MMS); (2) Very successful annual and semiannual meetings in Oxford Mississippi in February and September, 2003; (3) Collection of piston cores from MC798 in support of the effort to evaluate the site for possible monitoring station installation; (4) Completion of the site evaluation effort including reports of all localities in the northern Gulf of Mexico where hydrates have been documented or are strongly suspected to exist on the sea floor or in the shallow subsurface; (5) Collection and preliminary evaluation of vent gases and core samples of hydrate from sites in Green Canyon and Mississippi Canyon, northern Gulf of Mexico; (6) Monitoring of gas activity on the sea floor, acoustically and thermally

  7. US Navy Submarine Sea Trial of NASA developed Multi-Gas Monitor

    NASA Technical Reports Server (NTRS)

    Mudgett, Paul D.; Manney, Joshua A.; Pilgrim, Jeffrey S.

    2017-01-01

    During a successful 2 year technology demonstration of the tunable diode laser spectroscopy (TDLS) based Multi-Gas Monitor (MGM) on the International Space Station (ISS), we began discussing with the US Navy the possibility of conducting a sea trial of an MGM on a submarine. The sea trial would also include a gas chromatography/differential mobility spectrometer based Air Quality Monitor (AQM), which is used operationally on ISS for select volatile organic compounds. AQM results will be the subject of a separate paper. The Navy’s interest in testing NASA equipment is in a planned update to the environmental monitoring equipment used aboard submarines. NASA’s goal is studying submarines as closed environment analogs to spacecraft. MGM’s core technology was developed by Vista Photonics Inc using Small Business Innovation Research (SBIR) grants and expanded for various applications using NASA program funding. The MGM measures oxygen, carbon dioxide, ammonia and water vapor in ambient air, displays concentrations with temperature and pressure, and stores 30 second moving averages. The sea trial involves colocating the instrument with the Central Air Monitor (CAM) and connecting it to rack power prior to departure, and letting it run during the entire sea trial of a few months duration. All data stored is inside MGM, with no connection to the vessel data bus. Crew intervention is limited to checking MGM periodically to see that it is working and power cycling if the display is OFF. After the trial is over, the unit with its data will be retrieved. Post sea trial calibration check and data analysis are planned and results will be compared with both CAM data and results from MGM’s ISS technology demonstration.

  8. US Navy Submarine Sea Trial of NASA developed Multi-Gas Monitor

    NASA Technical Reports Server (NTRS)

    Mudgett, Paul D.; Manney, Joshua A.; Smith, Matthew J.; O'Connor, Sara Jane; Pilgrim, Jeffrey S.

    2017-01-01

    During a successful 2 year technology demonstration of the tunable diode laser spectroscopy (TDLS) based Multi-Gas Monitor (MGM) on the International Space Station (ISS), we began discussing with the US Navy the possibility of conducting a sea trial of an MGM on a submarine. The sea trial would also include a gas chromatography/differential mobility spectrometer based Air Quality Monitor (AQM), which is used operationally on ISS for volatile organic compound analysis. AQM preparation and results will be the subject of a separate paper. The Navy's interest in testing NASA equipment in general relates to their ongoing search for better air monitoring technology. NASA's goal is studying submarines as closed environment analogs to spacecraft. MGM's core technology was developed by Vista Photonics Inc. using Small Business Innovation Research (SBIR) grants and expanded for various applications using NASA program funding. The MGM measures oxygen, carbon dioxide, ammonia and water vapor in ambient air, displays concentrations with temperature and pressure, and stores 30 second moving averages. The sea trial involves collocating the instrument with the Central Atmosphere Monitoring System (CAMS Mk II) of the submarine, connecting it to rack power prior to departure, and letting it run during the entire 90 day patrol. All data is stored within MGM, with no connection to the vessel data bus. Crew intervention is limited to checking MGM periodically to see that it is working and power cycling if necessary. After the trial is over, the unit with its data will be retrieved. Post sea trial calibration check and data analysis are planned and results will be compared with both CAMS Mk II data and results from MGM's ISS technology demonstration. Since the sea trial itself has been delayed, this paper describes the preparation of MGM for the sea trial and also provides a summary of the latest data from the ISS MGM technology demonstration.

  9. Dual-chamber inflatable oil boom

    SciTech Connect

    Blair, R.M.; Tedeschi, E.T.

    1993-08-24

    An elongated floating material containment boom section is described having a normally vertical ballasted skirt depending from flotation means, and convertible from a flattened collapsed condition to a deployable condition wherein buoyancy chamber means extending along the upper edge of said skirt are inflated to expanded buoyant configuration, including: a gas-impervious sleeve extending along the upper edge of said normally vertical skirt forming a first outer collapsible and inflatable flotation chamber, a first inflation valve connecting the interior of said sleeve with the ambient atmosphere, through which gas under pressure may be introduced into said sleeve to inflate said first buoyant outer flotation chamber, elongated gas-impervious tube means positioned inside said outer flotation chamber and forming second collapsible and inflatable internal flotation bladder chamber means, second inflation valve means connecting the interior of said bladder means through said outer flotation chamber to the ambient atmosphere through which gas under pressure may be introduced into said bladder means to inflate it forming said second flotation chamber means inside said outer flotation chamber.

  10. Development of a rest gas ionisation profile monitor for the CERN Proton Synchrotron based on a Timepix3 pixel detector

    NASA Astrophysics Data System (ADS)

    Levasseur, S.; Dehning, B.; Gibson, S.; Sandberg, H.; Sapinski, M.; Sato, K.; Schneider, G.; Storey, J.

    2017-02-01

    A fast non-destructive transverse profile monitor, named PS Beam Gas Ionization monitor (PS- BGI), is under development at CERN for the Proton Synchrotron (PS). This monitor infers the beam profile from the transverse distribution of electrons created by the ionisation of rest gas molecules by the high energy beam particles. The distribution is measured by accelerating the electrons onto an imaging detector based on Timepix3 (TPX3). This detector consists of hybrid pixel detector assemblies mounted on a ceramic carrier board and flexible printed circuit cables which have been developed specifically for operation in an ultra high vacuum environment.

  11. In situ gas concentrations in the Kumano forearc basin from drilling mud gas monitoring and sonic velocity data (IODP NanTroSEIZE Exp. 319 Site C0009)

    NASA Astrophysics Data System (ADS)

    Wiersberg, T.; Doan, M.-L.; Schleicher, A. M.; Horiguchi, K.; Eguchi, N.; Erzinger, J.

    2012-04-01

    Conventional IODP shipboard methods of gas investigations comprise gas sampling from core voids and headspace gas sampling followed by shipboard gas analysis. These methods possibly underestimate the in situ gas concentration due to core degassing during retrieval and handling on deck. In few cases, a Pressure Core Sampler (PCS) was used in the past to overcome this problem, providing gas concentrations one or two order of magnitude higher than headspace gas analysis from corresponding depths. Here, we describe two new techniques applied during IODP NanTroSEIZE Exp. 319 Site C0009 riser drilling in the Kumano forearc basin to estimate in situ gas concentrations without drill core recovery. During riser drilling of site C0009 between 703 to 1594 mbsf, gas was continuously extracted from returing drilling mud and analysed in real-time (drill mud gas monitoring). This method results in information on the gas composition and gas concentration at depth. The chemical (C1-C3) and isotope (δ13C, H/D) composition of hydrocarbons, the only formation-derived gases identified in drill mud, demonstrate a microbial hydrocarbon gas source mixing with small but increasing amounts of thermogenic gas at greater depth. Methane content in drilling mud semi-quantitatively correlates with visible allochtonous material (wood, lignite) in drilling cuttings. In situ gas concentration determination from drill mud gas monitoring based on the assumption that gas is either liberated from the rock into the drilling mud during drilling and ascent with the mud column or remains in the pore space of the drilling cuttings. Drilling mud gas data were calibrated with a defined amount of C2H2 (175 l [STP]) from a carbide test and result in methane concentrations reaching up to 24 lgas/lsediment, in good agreement with findings from other IODP Legs using the PCS. Hydrocarbon gas concentrations in drilling cuttings from C0009 are significantly lower, indicating cuttings outgassing during ascent of the

  12. Specific features of SRS-CARS monitoring of low impurity concentrations of hydrogen in dense gas mixtures

    NASA Astrophysics Data System (ADS)

    Mikheev, Gennady M.; Mogileva, Tatyana N.; Popov, Aleksey Yu.

    2006-09-01

    The possibility of measuring the hydrogen impurity concentration in dense gas mixtures by coherent anti-Stokes Raman scattering (CARS) is studied. In this technique, biharmonic laser pumping based on stimulated Raman scattering (SRS) in compressed hydrogen is used. Because of the interference between the coherent scattering components from buffer gas molecules and molecules of the impurity to be detected, the signal recorded may depend on the hydrogen concentration by a parabolic law, which has a minimum and makes the results uncertain. It is shown that this uncertainty can be removed if the frequency of the biharmonic laser pump, which is produced by the SRS oscillator, somewhat differs from the frequency of molecular oscillations of hydrogen in the test mixture. A sensitivity of 5 ppm is obtained as applied to the hydrogen-air mixture under normal pressure. The description of a set-up for the determination of the coefficient of the hydrogen diffusion in gas mixtures is given. The main assembly units are a diffusion chamber and an automated laser system for the selective hydrogen diagnostics in gas mixtures by the SRS-CARS method. The determination of the diffusion coefficient is based on the approximation of the experimental data describing the hydrogen concentration varying with time at a specified point in the diffusion chamber and the accurate solution of the diffusion equation for the selected one-dimensional geometry of the experiment.

  13. Continuous Gas Monitoring at the Unzen-Conduit-Drilling USDP-4

    NASA Astrophysics Data System (ADS)

    Tretner, A.; Zimmer, M.; Erzinger, J.; Saito, M.; Nakada, S.

    2005-12-01

    Unzen Volcano, located in the Shimabara Peninsula, Kyushu, southwest Japan, was selected as one of the Decade Volcanoes of the United Nation's Decade of Natural Disaster Reduction, since it represents an important type of dangerous volcano. The last eruption (1990-95) was monitored and investigated in detail, yielding several models on the eruption mechanism and magmatic processes. The focus of USDP4 - drilling was to further clarify the regional crustal structure and magma evolution processes that control the manner of growth and failure of the volcano. In addition, processes of conduit formation, magma degassing, and magma's interaction with groundwater was investigated. Petrological investigations show, that Unzen magma in the conduit contained 4-5 wt.% water, whereas water content of the lava at the surface is very small. It was modelled that the water was released at less that 1-2 km depth. In view of these constraints different physico-chemical models show a strong increase in magma viscosity and a pressure drop directly below the growing dome. The gas phase dissolved in the drill mud was analyzed continuously with an online gas monitoring system. The aim was to receive a gas profile along the whole borehole length in order to gain information on the volcano fluid circulation system, to detect possible pathways for gases produced during magma degassing, and to determine hydrothermal and/or volcanic fluid inflow horizons. N2, O2, CO2, CH4, H2S, H2, He and Ar analyses were achieved with a quadrupol mass spectrometer; 222Rn was measured with a Lucas cell alpha detecotor. This data and subsequent isotopic studies contribute in particular to the discussed models about the eruptive behavior of Mt. Unzen. However, limitations were given due to the extremely difficult drilling conditions. The highly fractured rock formation led to loss of drill mud circulation mainly in the shallow parts. First results show that significant fluid inflow horizons didn't occur above

  14. Barometric gas transport along faults and its application to nuclear test-ban monitoring

    SciTech Connect

    Carrigan, C. R.; Heinle, R. A.; Hudson, G. B.; Nitao, J. J.; Zucca, J. J.

    1997-06-01

    Underground nuclear explosions produce a unique but evanescent set of radionuclide gases that potentially can be used in the context of an on-site, test-ban monitoring program to differentiate them from other detected events such as earthquakes or mining activity. In Part I of this report we describe an experiment to evaluate the upward transport of gases from an underground explosion using two gas tracers with very different diffusivities that were released in a 400- m-deep, chemical explosive detonation. The less diffusive (more massive) tracer was detected on a nearby geologic fault 50 days following the detonation while the more diffusive tracer was-- detected 375 days after release. Computer simulations indicate that the arrival time and the chromatographic behavior of transport are characteristic of barometrically induced flow in a fractured, porous matrix regime. For a hypothetical 1-kiloton fission explosion subject to the same weather and gas transport conditions of the chemical explosion, simulations predict the delectability of argon-37 after 80 days in spite of depletion by radioactive decay. Largely because of the earlier arrival of xenon-133, owing to its lower binary gas diffusivity, the exceedingly short lived isotope should also be detectable-arriving about 30 days earlier than argon. in Part II we consider that our prediction of the delectability of argon and xenon is based upon the small volume (0.00001 M3) sampling technique of the NPE tracer-gas sampling study while actual sampling for radionuclides would involve drawing much larger volume (possibly 0.1- 1 M3) gas samples from the near-surface.

  15. Compact Laser-Based Sensors for Monitoring and Control of Gas Turbine Combustors

    NASA Technical Reports Server (NTRS)

    Hanson, Ronald K.; Jeffries, Jay B.

    2003-01-01

    Research is reported on the development of sensors for gas turbine combustor applications that measure real-time gas temperature using near-infrared water vapor absorption and concentration in the combustor exhaust of trace quantities of pollutant NO and CO using mid-infrared absorption. Gas temperature is extracted from the relative absorption strength of two near-infrared transitions of water vapor. From a survey of the water vapor absorption spectrum, two overtone transitions near 1800 nm were selected that can be rapidly scanned in wavelength by injection current tuning a single DFB diode laser. From the ratio of the absorbances on these selected transitions, a path-integrated gas temperature can be extracted in near-real time. Demonstration measurements with this new temperature sensor showed that combustor instabilities could be identified in the power spectrum of the temperature versus time record. These results suggest that this strategy is extremely promising for gas turbine combustor control applications. Measurements of the concentration of NO and CO in the combustor exhaust are demonstrated with mid-infrared transitions using thermo-electrically cooled, quantum cascade lasers operating near 5.26 and 4.62 microns respectively. Measurements of NO are performed in an insulated exhaust duct of a C2H4-air flame at temperatures of approximately 600 K. CO measurements are performed above a rich H2-air flame seeded with CO2 and cooled with excess N2 to 1150 K. Using a balanced ratiometric detection technique a sensitivity of 0.36 ppm-m was achieved for NO and 0.21 ppm-m for CO. Comparisons between measured and predicted water-vapor and CO2 interference are discussed. The mid-infrared laser quantum cascade laser technology is in its infancy; however, these measurements demonstrate the potential for pollutant monitoring in exhaust gases with mid-IR laser absorption.

  16. Monitoring and modeling wetland chloride concentrations in relationship to oil and gas development

    USGS Publications Warehouse

    Post van der Burg, Max; Tangen, Brian A.

    2015-01-01

    Extraction of oil and gas via unconventional methods is becoming an important aspect of energy production worldwide. Studying the effects of this development in countries where these technologies are being widely used may provide other countries, where development may be proposed, with some insight in terms of concerns associated with development. A fairly recent expansion of unconventional oil and gas development in North America provides such an opportunity. Rapid increases in energy development in North America have caught the attention of managers and scientists as a potential stressor for wildlife and their habitats. Of particular concern in the Northern Great Plains of the U.S. is the potential for chloride-rich produced water associated with unconventional oil and gas development to alter the water chemistry of wetlands. We describe a landscape scale modeling approach designed to examine the relationship between potential chloride contamination in wetlands and patterns of oil and gas development. We used a spatial Bayesian hierarchical modeling approach to assess multiple models explaining chloride concentrations in wetlands. These models included effects related to oil and gas wells (e.g. age of wells, number of wells) and surficial geology (e.g. glacial till, outwash). We found that the model containing the number of wells and the surficial geology surrounding a wetland best explained variation in chloride concentrations. Our spatial predictions showed regions of localized high chloride concentrations. Given the spatiotemporal variability of regional wetland water chemistry, we do not regard our results as predictions of contamination, but rather as a way to identify locations that may require more intensive sampling or further investigation. We suggest that an approach like the one outlined here could easily be extended to more of an adaptive monitoring approach to answer questions about chloride contamination risk that are of interest to managers.

  17. Monitoring and modeling wetland chloride concentrations in relationship to oil and gas development.

    PubMed

    Post van der Burg, Max; Tangen, Brian A

    2015-03-01

    Extraction of oil and gas via unconventional methods is becoming an important aspect of energy production worldwide. Studying the effects of this development in countries where these technologies are being widely used may provide other countries, where development may be proposed, with some insight in terms of concerns associated with development. A fairly recent expansion of unconventional oil and gas development in North America provides such an opportunity. Rapid increases in energy development in North America have caught the attention of managers and scientists as a potential stressor for wildlife and their habitats. Of particular concern in the Northern Great Plains of the U.S. is the potential for chloride-rich produced water associated with unconventional oil and gas development to alter the water chemistry of wetlands. We describe a landscape scale modeling approach designed to examine the relationship between potential chloride contamination in wetlands and patterns of oil and gas development. We used a spatial Bayesian hierarchical modeling approach to assess multiple models explaining chloride concentrations in wetlands. These models included effects related to oil and gas wells (e.g. age of wells, number of wells) and surficial geology (e.g. glacial till, outwash). We found that the model containing the number of wells and the surficial geology surrounding a wetland best explained variation in chloride concentrations. Our spatial predictions showed regions of localized high chloride concentrations. Given the spatiotemporal variability of regional wetland water chemistry, we do not regard our results as predictions of contamination, but rather as a way to identify locations that may require more intensive sampling or further investigation. We suggest that an approach like the one outlined here could easily be extended to more of an adaptive monitoring approach to answer questions about chloride contamination risk that are of interest to managers.

  18. Automatic Web-Based, Radio-Network System To Monitor And Control Equipment For Investigating Gas Flux At Water - Air Interfaces

    NASA Astrophysics Data System (ADS)

    Duc, N. T.; Silverstein, S.; Wik, M.; Beckman, P.; Crill, P. M.; Bastviken, D.; Varner, R. K.

    2015-12-01

    Aquatic ecosystems are major sources of greenhouse gases (GHG). Robust measurements of natural GHG emissions are vital for evaluating regional to global carbon budgets and for assessing climate feedbacks on natural emissions to improve climate models. Diffusive and ebullitive (bubble) transport are two major pathways of gas release from surface waters. To capture the high temporal variability of these fluxes in a well-defined footprint, we designed and built an inexpensive automatic device that includes an easily mobile diffusive flux chamber and a bubble counter, all in one. Besides a function of automatically collecting gas samples for subsequent various analyses in the laboratory, this device utilizes low cost CO2 sensor (SenseAir, Sweden) and CH4 sensor (Figaro, Japan) to measure GHG fluxes. To measure the spatial variability of emissions, each of the devices is equipped with an XBee module to enable a local radio communication DigiMesh network for time synchronization and data readout at a server-controller station on the lakeshore. Software of this server-controller is operated on a low cost Raspberry Pi computer which has a 3G connection for remote monitoring - controlling functions from anywhere in the world. From field studies in Abisko, Sweden in summer 2014 and 2015, the system has resulted in measurements of GHG fluxes comparable to manual methods. In addition, the deployments have shown the advantage of a low cost automatic network system to study GHG fluxes on lakes in remote locations.

  19. Gas monitoring during the CO2 back production field test at the Ketzin pilot site

    NASA Astrophysics Data System (ADS)

    Szizybalski, Alexandra; Zimmer, Martin; Kujawa, Christian; Erzinger, Jörg

    2015-04-01

    fluids before the injection of CO2 showed that CH4, CO2, H2 and N2 are present in the original formation fluid (0.17 mg/l, 0.08 mg/l, 0.14 mg/l, 17.9 mg/l fluid; Morozova et al., 2010). The observed N2 concentrations in the back-produced gas may, therefore, result from the field tests and from injection management or from the original formation fluid. Results of the isotopic measurements are in preparation. Morozova, D., Wandrey, M., Alawi, M., Zimmer, M., Vieth, A., Zettlitzer, M., Wuerdemann, H. (2010): Monitoring of the microbial community composition in saline aquifers during CO2 storage by fluorescence in situ hybridisation. International Journal of Greenhouse Gas Control, Volume 4, Pages 981-989. doi:10.1016/j.ijggc.2009.11.014.

  20. Effect of 220Rn gas concentration distribution on its transmission from a delay chamber: evolving a CFD-based uniformity index.

    PubMed

    Agarwal, T K; Joshi, M; Sahoo, B K; Kanse, S D; Sapra, B K

    2016-03-01

    (220)Rn mitigation can be achieved by delay chamber technique, which relies on the advantage of its short half-life. However, flow rate as well as inlet-outlet position for the delay chamber can have a significant impact on (220)Rn concentration distribution patterns and hence transmission factor. In the present study, computational fluid dynamics simulations to estimate the concentration distribution has been carried out in a chamber of 0.5 m(3) for the combination of six different inlet-outlet positions and five different flow rates. Subsequently, the transmission factor (TF) for the chamber was evaluated and found to be highly dependent on the flow rate and inlet-outlet positions. For ease of scale up, the dependency of TF on the flow rate and the inlet-outlet positions is best summarised by relative transmission factor (RTF), which is the ratio of the TFs for the case of inlet and outlet on different faces to that on the same face.

  1. Future Issues and Approaches to Health Monitoring and Failure Prevention for Oil-Free Gas Turbines

    NASA Technical Reports Server (NTRS)

    DellaCorte, Christopher

    2004-01-01

    Recent technology advances in foil air bearings, high temperature solid lubricants and computer based modeling has enabled the development of small Oil-Free gas turbines. These turbomachines are currently commercialized as small (<100 kW) microturbine generators and larger machines are being developed. Based upon these successes and the high potential payoffs offered by Oil-Free systems, NASA, industry, and other government entities are anticipating Oil-Free gas turbine propulsion systems to proliferate future markets. Since an Oil-Free engine has no oil system, traditional approaches to health monitoring and diagnostics, such as chip detection, oil analysis, and possibly vibration signature analyses (e.g., ball pass frequency) will be unavailable. As such, new approaches will need to be considered. These could include shaft orbit analyses, foil bearing temperature measurements, embedded wear sensors and start-up/coast down speed analysis. In addition, novel, as yet undeveloped techniques may emerge based upon concurrent developments in MEMS technology. This paper introduces Oil-Free technology, reviews the current state of the art and potential for future turbomachinery applications and discusses possible approaches to health monitoring, diagnostics and failure prevention.

  2. Response of CO2 Concentration in Andisol to Rainfall Events by Using Buried Tubing Gas Monitoring System

    NASA Astrophysics Data System (ADS)

    Endo, Toshifumi; Tokida, Takeshi; Imoto, Hiromi; Nishimura, Taku; Miyazaki, Tsuyoshi

    For the purpose of continuous soil CO2 gas monitoring, gas permeable resins were evaluated. Among polytetrafluoroethylen (PTFE), polyfluoroethylene propylene (PFEP) and silicone, the silicone rubber tube had highest permeability for oxygen gas. Buried Tubing Gas Monitoring System (BT-GMS) consisting of silicone rubber tube connected to a Non-diffuse infrared (NDIR) -CO2 gas and galvanic cell O2 gas sensors were constructed, and buried into an Andisol upland field at a depth of 20cm. Thermo-couples and EC-5 soil moisture sensors were inserted into 10 and 20cm deep layers. Soil CO2 gas concentration, temperature and moisture were continuously monitored for 5 months. Soil CO2 concentration was sensitive to rainfall events and soil moisture change. Responses were keen during summer until early autumn when soil temperature was higher than 20°C. Then, when soil temperature got lower the response tended to be dull. This suggested quick CO2 gas concentration change following a rainfall event was mostly due to enhancement in soil respiration with soil moisture rise.

  3. Seismic modeling to monitor CO2 geological storage: The Atzbach-Schwanenstadt gas field

    NASA Astrophysics Data System (ADS)

    Picotti, Stefano; Carcione, José M.; Gei, Davide; Rossi, Giuliana; Santos, Juan E.

    2012-06-01

    We develop a petro-elastical numerical methodology to compute realistic synthetic seismograms and analyze the sensitivity of the seismic response when injecting carbon dioxide (CO2) in a depleted gas reservoir. The petro-elastical model describes the seismic properties of the reservoir rock saturated with CO2, methane and brine, and allows us to estimate the distribution and saturation of CO2 during the injection process. The gas properties, as a function of the in-situ pressure and temperature conditions, are computed with the Peng-Robinson equation of state, taking into account the absorption of gas by brine. Wave attenuation and velocity dispersion are based on the mesoscopic loss mechanism, which is simulated by an upscaling procedure to obtain an equivalent viscoelastic medium corresponding to partial saturation at the mesoscopic scale. Having the equivalent complex and frequency-dependent bulk (dilatational) modulus, we include shear attenuation and perform numerical simulations of wave propagation at the macroscale by solving the viscoelastic differential equations using the memory-variable approach. The pseudo-spectral modeling method allows general material variability and provides a complete and accurate characterization of the reservoir. The methodology is used to assess the sensitivity of the seismic method for monitoring the CO2 geological storage at the Atzbach-Schwanestadt depleted gas-field in Austria. The objective of monitoring is the detection of the CO2 plume in the reservoir and possible leakages of CO2. The leakages are located at different depths, where the CO2 is present as gaseous, liquid and supercritical phases. Even though the differences can be very subtle, this work shows that seismic monitoring of CO2 from the surface is possible. While the identification of shallow leakages is feasible, the detection of the plume and deep leakages, located in the caprock just above the injection formation, is more difficult, but possible by using

  4. Long-range open-path greenhouse gas monitoring using mid-infrared laser dispersion spectroscopy

    NASA Astrophysics Data System (ADS)

    Daghestani, Nart; Brownsword, Richard; Weidmann, Damien

    2015-04-01

    Accurate and sensitive methods of monitoring greenhouse gas (GHG) emission over large areas has become a pressing need to deliver improved estimates of both human-made and natural GHG budgets. These needs relate to a variety of sectors including environmental monitoring, energy, oil and gas industry, waste management, biogenic emission characterization, and leak detection. To address the needs, long-distance open-path laser spectroscopy methods offer significant advantages in terms of temporal resolution, sensitivity, compactness and cost effectiveness. Path-integrated mixing ratio measurements stemming from long open-path laser spectrometers can provide emission mapping when combined with meteorological data and/or through tomographic approaches. Laser absorption spectroscopy is the predominant method of detecting gasses over long integrated path lengths. The development of dispersion spectrometers measuring tiny refractive index changes, rather than optical power transmission, may offer a set of specific advantages1. These include greater immunity to laser power fluctuations, greater dynamic range due to the linearity of dispersion, and ideally a zero baseline signal easing quantitative retrievals of path integrated mixing ratios. Chirped laser dispersion spectrometers (CLaDS) developed for the monitoring of atmospheric methane and carbon dioxide will be presented. Using quantum cascade laser as the source, a minimalistic and compact system operating at 7.8 μm has been developed and demonstrated for the monitoring of atmospheric methane over a 90 meter open path2. Through full instrument modelling and error propagation analysis, precision of 3 ppm.m.Hz-0.5 has been established (one sigma precision for atmospheric methane normalized over a 1 m path and 1 s measurement duration). The system was fully functional in the rain, sleet, and moderate fog. The physical model and system concept of CLaDS can be adapted to any greenhouse gas species. Currently we are

  5. Remote optical sensing network for gas monitoring based on laser spectroscopy over hybrid TDM/WDM-PONs

    NASA Astrophysics Data System (ADS)

    Huang, Ming-Fang; Plant, Genevieve; Tanaka, Akihiro; Cvijetic, Neda; Tian, Yue; Wysocki, Gerard; Wang, Ting

    2015-09-01

    We propose an optical gas sensing network directly overlaid onto optical access networks, hybrid TDM/WDM-PONs. Centralized remote gas monitoring is demonstrated using three different sensing technologies: Chirp Laser Dispersion Spectroscopy (CLaDS), Direct Laser Absorption Spectroscopy (DLAS) and tunable diode laser absorption spectroscopy (TDLS). DLAS performs fast threshold detection while CLaDS provides quantitative information about the gas. Additionally, TDLS utilizes a cost-effective solution for multiple gases detection. The results confirm that centralized remote gas sensing can be realized in optical communication networks using standard single-mode fiber (SMF), which provides a real time, low cost, and maintenance-free solution.

  6. High sensitive gas detection and isotopic measurement for the applications of industrial emission online monitoring and air pollution source tracking

    NASA Astrophysics Data System (ADS)

    Dong, Fengzhong; Zhang, Zhirong; Xia, Hua; Cui, Xiaojuan; Pang, Tao; Wu, Bian; Chen, Weidong; Sigrist, Markus

    2015-04-01

    High sensitive gas detection and isotopic measurements have been widely employed in the industrial and safety production. The recent progress made by our group on high sensitive gas detection with technologies of TDLAS, off-axis integrated cavity output spectroscopy (OA-ICOS) and cavity ring-down spectroscopy (CRDS) will be briefly summarized in this report. Some works for field applications of industrial emission online monitoring and gas leakage detection in oil tank farm with TDLAS are first presented, and then part of our most recent researches on isotopic gas detection with OA-ICOS and CRDS for tracking of pollution sources are also introduced.

  7. Gas Bubble Trauma Monitoring and Research of Juvenile Salmonids, 1994-1995 Progress Report.

    SciTech Connect

    Hans, Karen M.

    1997-07-01

    This report describes laboratory and field monitoring studies of gas bubble trauma (GBT) in migrating juvenile salmonids in the Snake and Columbia rivers. The first chapter describes laboratory studies of the progression of GBT signs leading to mortality and the use of the signs for GBT assessment. The progression and severity of GBT signs in juvenile salmonids exposed to different levels of total dissolved gas (TDG) and temperatures was assessed and quantified. Next, the prevalence, severity, and individual variation of GBT signs was evaluated to attempt to relate them to mortality. Finally, methods for gill examination in fish exposed to high TDG were developed and evaluated. Primary findings were: (1) no single sign of GBT was clearly correlated with mortality, but many GBT signs progressively worsened; (2) both prevalence and severity of GBT signs in several tissues is necessary; (3) bubbles in the lateral line were the earliest sign of GBT, showed progressive worsening, and had low individual variation but may develop poorly during chronic exposures; (4) fin bubbles had high prevalence, progressively worsened, and may be a persistent sign of GBT; and (5) gill bubbles appear to be the proximate cause of death but may only be relevant at high TDG levels and are difficult to examine. Chapter Two describes monitoring results of juvenile salmonids for signs of GBT. Emigrating fish were collected and examined for bubbles in fins and lateral lines. Preliminary findings were: (1) few fish had signs of GBT, but prevalence and severity appeared to increase as fish migrated downstream; (2) there was no apparent correlation between GBT signs in the fins, lateral line, or gills; (3) prevalence and severity of GBT was suggestive of long-term, non-lethal exposure to relatively low level gas supersaturated water; and (4) it appeared that GBT was not a threat to migrating juvenile salmonids. 24 refs., 26 figs., 3 tabs.

  8. Portable remote Raman system for monitoring hydrocarbon, gas hydrates and explosives in the environment.

    PubMed

    Sharma, Shiv K; Misra, Anupam K; Sharma, Bhavna

    2005-08-01

    We report our initial efforts to use a small portable Raman system for stand-off detection and identification of various types of organic chemicals including benzene, toluene, ethyl benzene and xylenes (BTEX). Both fiber-optic (FO) coupled and a directly coupled f/2.2 spectrograph with the telescope have been developed and tested. A frequency-doubled Nd:YAG pulsed laser (20 Hz, 532 nm, 35 mJ/pulse) is used as the excitation source. The operational range of the FO coupled Raman system was tested to 66 m, and the directly coupled system was tested to a distance of 120 m. We have also measured remote Raman spectra of compressed methane gas and methane gas hydrate. The usefulness of the remote Raman system for identifying unknown compounds is demonstrated by measuring stand-off spectra of two plastic explosives, e.g. tri-amino tri-nitrobenzene (TATB) and beta-HMX at 10 m stand-off distance. The remote Raman system will be useful for terrestrial applications such as monitoring environmental pollution, in identifying unknown materials in public places in 10s or less, and for detecting hydrocarbon plumes and gas hydrates on planetary surfaces such as Mars.

  9. The Mark II Vertex Drift Chamber

    SciTech Connect

    Alexander, J.P.; Baggs, R.; Fujino, D.; Hayes, K.; Hoard, C.; Hower, N.; Hutchinson, D.; Jaros, J.A.; Koetke, D.; Kowalski, L.A.

    1989-03-01

    We have completed constructing and begun operating the Mark II Drift Chamber Vertex Detector. The chamber, based on a modified jet cell design, achieves 30 {mu}m spatial resolution and <1000 {mu}m track-pair resolution in pressurized CO{sub 2} gas mixtures. Special emphasis has been placed on controlling systematic errors including the use of novel construction techniques which permit accurate wire placement. Chamber performance has been studied with cosmic ray tracks collected with the chamber located both inside and outside the Mark II. Results on spatial resolution, average pulse shape, and some properties of CO{sub 2} mixtures are presented. 10 refs., 12 figs., 1 tab.

  10. Thrust chamber thermal barrier coating techniques

    NASA Technical Reports Server (NTRS)

    Quentmeyer, Richard J.

    1989-01-01

    Methods for applying thermal barrier coatings to the hot-gas side wall of rocket thrust chambers in order to significantly reduce the heat transfer in high heat flux regions has been the focus of technology efforts for many years. A successful technique developed by NASA-Lewis that starts with the coating on a mandrel and then builds the thrust chamber around it by electroforming appropriate materials is described. This results in a smooth coating with exceptional adherence, as was demonstrated in hot fire rig tests. The low cycle fatigue life of chambers with coatings applied in this manner was increased dramatically compared to uncoated chambers.

  11. Thrust chamber thermal barrier coating techniques

    NASA Technical Reports Server (NTRS)

    Quentmeyer, Richard J.

    1988-01-01

    Methods for applying thermal barrier coatings to the hot-gas side wall of rocket thrust chambers in order to significantly reduce the heat transfer in high heat flux regions was the focus of technology efforts for many years. This paper describes a successful technique developed by the Lewis Research Center that starts with the coating of a mandrel and then builds the thrust chamber around it by electroforming appropriate materials. This results in a smooth coating with exceptional adherence, demonstrated in hot fire rig tests. The low cycle fatigue life of chambers with coatings applied in this manner was increased dramatically compared to uncoated chambers.

  12. Design and Performance of a Gas Chromatograph for Automatic Monitoring of Pollutants in Ambient Air

    NASA Technical Reports Server (NTRS)

    Villalobos, R.; Stevens, D.; LeBlanc, R.; Braun, L.

    1971-01-01

    In recent years, interest in air pollution constituents has focused on carbon monoxide and hydrocarbons as prime components of polluted air. Instrumental methods have been developed, and commercial instruments for continuous monitoring of these components have been available for a number of years. For the measurement of carbon monoxide, non-dispersive infrared spectroscopy has been the accepted tool, in spite of its marginal sensitivity at low parts-per-million levels. For continuously monitoring total hydrocarbons, the hydrogen flame ionization analyzer has been widely accepted as the preferred method. The inadequacy of this latter method became evident when it was concluded that methane is non-reactive and cannot be considered a contaminant even though present at over 1 ppm in the earth's atmosphere. Hence, the need for measuring methane separately became apparent as a means of measuring the reactive and potentially harmful non-methane hydrocarbons fraction. A gas chromatographic method for the measurement of methane and total hydrocarbons which met these requirements has been developed. In this technique, methane was separated on conventional gas chromatographic columns and detected by a hydrogen flame ionization detector (FID) while the total hydrocarbons were obtained by introducing a second sample directly into the FID without separating the various components. The reactive, or non-methane hydrocarbons, were determined by difference. Carbon monoxide was also measured after converting to methane over a heated catalyst to render it detectable by the FID. The development of this method made it possible to perform these measurements with a sensitivity of as much as 1 ppm full scale and a minimum detectability of 20 ppb. Incorporating this technique, criteria were developed by APCO for a second generation continuous automatic instrument for atmospheric monitoring stations.

  13. Developing monitoring plans to detect spills related to natural gas production.

    PubMed

    Harris, Aubrey E; Hopkinson, Leslie; Soeder, Daniel J

    2016-11-01

    Surface water is at risk from Marcellus Shale operations because of chemical storage on drill pads during hydraulic fracturing operations, and the return of water high in total dissolved solids (up to 345 g/L) from shale gas production. This research evaluated how two commercial, off-the-shelf water quality sensors responded to simulated surface water pollution events associated with Marcellus Shale development. First, peak concentrations of contaminants from typical spill events in monitored watersheds were estimated using regression techniques. Laboratory measurements were then conducted to determine how standard in-stream instrumentation that monitor conductivity, pH, temperature, and dissolved oxygen responded to three potential spill materials: ethylene glycol (corrosion inhibitor), drilling mud, and produced water. Solutions ranging from 0 to 50 ppm of each spill material were assessed. Over this range, the specific conductivity increased on average by 19.9, 27.9, and 70 μS/cm for drilling mud, ethylene glycol, and produced water, respectively. On average, minor changes in pH (0.5-0.8) and dissolved oxygen (0.13-0.23 ppm) were observed. While continuous monitoring may be part of the strategy for detecting spills to surface water, these minor impacts to water quality highlight the difficulty in detecting spill events. When practical, sensors should be placed at the mouths of small watersheds where drilling activities or spill risks are present, as contaminant travel distance strongly affects concentrations in surface water systems.

  14. Vacuum chamber with a supersonic-flow aerodynamic window

    DOEpatents

    Hanson, C.L.

    1980-10-14

    A supersonic flow aerodynamic window is disclosed whereby a steam ejector situated in a primary chamber at vacuum exhausts superheated steam toward an orifice to a region of higher pressure, creating a barrier to the gas in the region of higher pressure which attempts to enter through the orifice. In a mixing chamber outside and in fluid communication with the primary chamber, superheated steam and gas are combined into a mixture which then enters the primary chamber through the orifice. At the point of impact of the ejector/superheated steam and the incoming gas/superheated steam mixture, a barrier is created to the gas attempting to enter the ejector chamber. This barrier, coupled with suitable vacuum pumping means and cooling means, serves to keep the steam ejector and primary chamber at a negative pressure, even though the primary chamber has an orifice to a region of higher pressure.

  15. Vacuum chamber with a supersonic flow aerodynamic window

    DOEpatents

    Hanson, Clark L.

    1982-01-01

    A supersonic flow aerodynamic window, whereby a steam ejector situated in a primary chamber at vacuum exhausts superheated steam toward an orifice to a region of higher pressure, creating a barrier to the gas in the region of higher pressure which attempts to enter through the orifice. In a mixing chamber outside and in fluid communication with the primary chamber, superheated steam and gas are combined into a mixture which then enters the primary chamber through the orifice. At the point of impact of the ejector/superheated steam and the incoming gas/superheated steam mixture, a barrier is created to the gas attempting to enter the ejector chamber. This barrier, coupled with suitable vacuum pumping means and cooling means, serves to keep the steam ejector and primary chamber at a negative pressure, even though the primary chamber has an orifice to a region of higher pressure.

  16. Metal-modified and vertically aligned carbon nanotube sensors array for landfill gas monitoring applications

    NASA Astrophysics Data System (ADS)

    Penza, M.; Rossi, R.; Alvisi, M.; Serra, E.

    2010-03-01

    Vertically aligned carbon nanotube (CNT) layers were synthesized on Fe-coated low-cost alumina substrates using radio-frequency plasma enhanced chemical vapour deposition (RF-PECVD) technology. A miniaturized CNT-based gas sensor array was developed for monitoring landfill gas (LFG) at a temperature of 150 °C. The sensor array was composed of 4 sensing elements with unmodified CNT, and CNT loaded with 5 nm nominally thick sputtered nanoclusters of platinum (Pt), ruthenium (Ru) and silver (Ag). Chemical analysis of multicomponent gas mixtures constituted of CO2, CH4, H2, NH3, CO and NO2 has been performed by the array sensor responses and pattern recognition based on principal component analysis (PCA). The PCA results demonstrate that the metal-decorated and vertically aligned CNT sensor array is able to discriminate the NO2 presence in the multicomponent mixture LFG. The NO2 gas detection in the mixture LFG was proved to be very sensitive, e.g.: the CNT:Ru sensor shows a relative change in the resistance of 1.50% and 0.55% for NO2 concentrations of 3.3 ppm and 330 ppb dispersed in the LFG, respectively, with a wide NO2 gas concentration range measured from 0.33 to 3.3 ppm, at the sensor temperature of 150 °C. The morphology and structure of the CNT networks have been characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM) and Raman spectroscopy. A forest-like nanostructure of vertically aligned CNT bundles in the multi-walled form appeared with a height of about 10 µm and a single-tube diameter varying in the range of 5-35 nm. The intensity ratio of the Raman spectroscopy D-peak and G-peak indicates the presence of disorder and defects in the CNT networks. The size of the metal (Pt, Ru, Ag) nanoclusters decorating the CNT top surface varies in the range of 5-50 nm. Functional characterization based on electrical charge transfer sensing mechanisms in the metal-modified CNT-chemoresistor array demonstrates high sensitivity by

  17. Design and performance of the KSC Biomass Production Chamber

    NASA Technical Reports Server (NTRS)

    Prince, Ralph P.; Knott, William M.; Sager, John C.; Hilding, Suzanne E.

    1987-01-01

    NASA's Controlled Ecological Life Support System program has instituted the Kennedy Space Center 'breadboard' project of which the Biomass Production Chamber (BPC) presently discussed is a part. The BPC is based on a modified hypobaric test vessel; its design parameters and operational parameters have been chosen in order to meet a wide range of plant-growing objectives aboard future spacecraft on long-duration missions. A control and data acquisition subsystem is used to maintain a common link between the heating, ventilation, and air conditioning system, the illumination system, the gas-circulation system, and the nutrient delivery and monitoring subsystems.

  18. Assessing the performance of the photo-acoustic infrared gas monitor for measuring CO(2), N(2)O, and CH(4) fluxes in two major cereal rotations.

    PubMed

    Tirol-Padre, Agnes; Rai, Munmun; Gathala, Mahesh; Sharma, Sheetal; Kumar, Virender; Sharma, Parbodh C; Sharma, Dinesh K; Wassmann, Reiner; Ladha, Jagdish

    2014-01-01

    Rapid, precise, and globally comparable methods for monitoring greenhouse gas (GHG) fluxes are required for accurate GHG inventories from different cropping systems and management practices. Manual gas sampling followed by gas chromatography (GC) is widely used for measuring GHG fluxes in agricultural fields, but is laborious and time-consuming. The photo-acoustic infrared gas monitoring system (PAS) with on-line gas sampling is an attractive option, although it has not been evaluated for measuring GHG fluxes in cereals in general and rice in particular. We compared N2 O, CO2 , and CH4 fluxes measured by GC and PAS from agricultural fields under the rice-wheat and maize-wheat systems during the wheat (winter), and maize/rice (monsoon) seasons in Haryana, India. All the PAS readings were corrected for baseline drifts over time and PAS-CH4 (PCH4 ) readings in flooded rice were corrected for water vapor interferences. The PCH4 readings in ambient air increased by 2.3 ppm for every 1000 mg cm(-3) increase in water vapor. The daily CO2 , N2 O, and CH4 fluxes measured by GC and PAS from the same chamber were not different in 93-98% of all the measurements made but the PAS exhibited greater precision for estimates of CO2 and N2 O fluxes in wheat and maize, and lower precision for CH4 flux in rice, than GC. The seasonal GC- and PAS-N2 O (PN2 O) fluxes in wheat and maize were not different but the PAS-CO2 (PCO2 ) flux in wheat was 14-39% higher than that of GC. In flooded rice, the seasonal PCH4 and PN2 O fluxes across N levels were higher than those of GC-CH4 and GC-N2 O fluxes by about 2- and 4fold, respectively. The PAS (i) proved to be a suitable alternative to GC for N2 O and CO2 flux measurements in wheat, and (ii) showed potential for obtaining accurate measurements of CH4 fluxes in flooded rice after making correction for changes in humidity.

  19. Ionization-chamber smoke detector system

    DOEpatents

    Roe, Robert F.

    1976-10-19

    This invention relates to an improved smoke-detection system of the ionization-chamber type. In the preferred embodiment, the system utilizes a conventional detector head comprising a measuring ionization chamber, a reference ionization chamber, and a normally non-conductive gas triode for discharging when a threshold concentration of airborne particulates is present in the measuring chamber. The improved system is designed to reduce false alarms caused by fluctuations in ambient temperature. Means are provided for periodically firing the gas discharge triode and each time recording the triggering voltage required. A computer compares each triggering voltage with its predecessor. The computer is programmed to energize an alarm if the difference between the two compared voltages is a relatively large value indicative of particulates in the measuring chamber and to disregard smaller differences typically resulting from changes in ambient temperature.

  20. An Integrated Architecture for On-Board Aircraft Engine Performance Trend Monitoring and Gas Path Fault Diagnostics

    NASA Technical Reports Server (NTRS)

    Simon, Donald L.

    2010-01-01

    Aircraft engine performance trend monitoring and gas path fault diagnostics are closely related technologies that assist operators in managing the health of their gas turbine engine assets. Trend monitoring is the process of monitoring the gradual performance change that an aircraft engine will naturally incur over time due to turbomachinery deterioration, while gas path diagnostics is the process of detecting and isolating the occurrence of any faults impacting engine flow-path performance. Today, performance trend monitoring and gas path fault diagnostic functions are performed by a combination of on-board and off-board strategies. On-board engine control computers contain logic that monitors for anomalous engine operation in real-time. Off-board ground stations are used to conduct fleet-wide engine trend monitoring and fault diagnostics based on data collected from each engine each flight. Continuing advances in avionics are enabling the migration of portions of the ground-based functionality on-board, giving rise to more sophisticated on-board engine health management capabilities. This paper reviews the conventional engine performance trend monitoring and gas path fault diagnostic architecture commonly applied today, and presents a proposed enhanced on-board architecture for future applications. The enhanced architecture gains real-time access to an expanded quantity of engine parameters, and provides advanced on-board model-based estimation capabilities. The benefits of the enhanced architecture include the real-time continuous monitoring of engine health, the early diagnosis of fault conditions, and the estimation of unmeasured engine performance parameters. A future vision to advance the enhanced architecture is also presented and discussed

  1. Hot-gas-side heat transfer with and without film cooling on a simulated nuclear rocket thrust chamber using H2-O2

    NASA Technical Reports Server (NTRS)

    Quentmeyer, R. J.; Schacht, R. L.; Jones, W. L.

    1972-01-01

    Heat-transfer coefficients were obtained on a thrust chamber which simulated the geometry of the NERVA nuclear rocket. The tests were performed with and without peripheral film cooling over a chamber pressure range of 1.05 million to 5.84 million newtons per square meter (153 to 847 psia). With no film cooling, the overall axial variation in the value of the correlation coefficient C of the equation (Stanton)* (Prandtl)* to the 0.7ths power = C(Reynolds)* to the -0.2ths power, where * indicates the reference enthalpy condition, was reduced 66 percent when the local diameter in the Reynolds number was replaced by the axial distance from the injector face. The average peak values of C were reduced 25 percent with 2 and 3.75 percent cooling and 50 percent with 7.5 percent cooling.

  2. A stream-based methane monitoring approach for evaluating groundwater impacts associated with unconventional gas development.

    PubMed

    Heilweil, Victor M; Stolp, Bert J; Kimball, Briant A; Susong, David D; Marston, Thomas M; Gardner, Philip M

    2013-01-01

    Gaining streams can provide an integrated signal of relatively large groundwater capture areas. In contrast to the point-specific nature of monitoring wells, gaining streams coalesce multiple flow paths. Impacts on groundwater quality from unconventional gas development may be evaluated at the watershed scale by the sampling of dissolved methane (CH4 ) along such streams. This paper describes a method for using stream CH4 concentrations, along with measurements of groundwater inflow and gas transfer velocity interpreted by 1-D stream transport modeling, to determine groundwater methane fluxes. While dissolved ionic tracers remain in the stream for long distances, the persistence of methane is not well documented. To test this method and evaluate CH4 persistence in a stream, a combined bromide (Br) and CH4 tracer injection was conducted on Nine-Mile Creek, a gaining stream in a gas development area in central Utah. A 35% gain in streamflow was determined from dilution of the Br tracer. The injected CH4 resulted in a fivefold increase in stream CH4 immediately below the injection site. CH4 and δ(13) CCH4 sampling showed it was not immediately lost to the atmosphere, but remained in the stream for more than 2000 m. A 1-D stream transport model simulating the decline in CH4 yielded an apparent gas transfer velocity of 4.5 m/d, describing the rate of loss to the atmosphere (possibly including some microbial consumption). The transport model was then calibrated to background stream CH4 in Nine-Mile Creek (prior to CH4 injection) in order to evaluate groundwater CH4 contributions. The total estimated CH4 load discharging to the stream along the study reach was 190 g/d, although using geochemical fingerprinting to determine its source was beyond the scope of the current study. This demonstrates the utility of stream-gas sampling as a reconnaissance tool for evaluating both natural and anthropogenic CH4 leakage from gas reservoirs into groundwater and surface water.

  3. Fission Product Monitoring of TRISO Coated Fuel For The Advanced Gas Reactor -1 Experiment

    SciTech Connect

    Dawn M. Scates; John K. Hartwell; John b. Walter

    2010-10-01

    The US Department of Energy has embarked on a series of tests of TRISO-coated particle reactor fuel intended for use in the Very High Temperature Reactor (VHTR) as part of the Advanced Gas Reactor (AGR) program. The AGR-1 TRISO fuel experiment, currently underway, is the first in a series of eight fuel tests planned for irradiation in the Advanced Test Reactor (ATR) located at the Idaho National Laboratory (INL). The AGR-1 experiment reached a peak compact averaged burn up of 9% FIMA with no known TRISO fuel particle failures in March 2008. The burnup goal for the majority of the fuel compacts is to have a compact averaged burnup greater than 18% FIMA and a minimum compact averaged burnup of 14% FIMA. At the INL the TRISO fuel in the AGR-1 experiment is closely monitored while it is being irradiated in the ATR. The effluent monitoring system used for the AGR-1 fuel is the Fission Product Monitoring System (FPMS). The FPMS is a valuable tool that provides near real-time data indicative of the AGR-1 test fuel performance and incorporates both high-purity germanium (HPGe) gamma-ray spectrometers and sodium iodide [NaI(Tl)] scintillation detector-based gross radiation monitors. To quantify the fuel performance, release-to-birth ratios (R/B’s) of radioactive fission gases are computed. The gamma-ray spectra acquired by the AGR-1 FPMS are analyzed and used to determine the released activities of specific fission gases, while a dedicated detector provides near-real time count rate information. Isotopic build up and depletion calculations provide the associated isotopic birth rates. This paper highlights the features of the FPMS, encompassing the equipment, methods and measures that enable the calculation of the release-to-birth ratios. Some preliminary results from the AGR-1 experiment are also presented.

  4. Fission Product Monitoring of TRISO Coated Fuel For The Advanced Gas Reactor -1 Experiment

    SciTech Connect

    Dawn M. Scates; John K Hartwell; John B. Walter

    2008-09-01

    The US Department of Energy has embarked on a series of tests of TRISO-coated particle reactor fuel intended for use in the Very High Temperature Reactor (VHTR) as part of the Advanced Gas Reactor (AGR) program. The AGR-1 TRISO fuel experiment, currently underway, is the first in a series of eight fuel tests planned for irradiation in the Advanced Test Reactor (ATR) located at the Idaho National Laboratory (INL). The AGR-1 experiment reached a peak compact averaged burn up of 9% FIMA with no known TRISO fuel particle failures in March 2008. The burnup goal for the majority of the fuel compacts is to have a compact averaged burnup greater than 18% FIMA and a minimum compact averaged burnup of 14% FIMA. At the INL the TRISO fuel in the AGR-1 experiment is closely monitored while it is being irradiated in the ATR. The effluent monitoring system used for the AGR-1 fuel is the Fission Product Monitoring System (FPMS). The FPMS is a valuable tool that provides near real-time data indicative of the AGR-1 test fuel performance and incorporates both high-purity germanium (HPGe) gamma-ray spectrometers and sodium iodide [NaI(Tl)] scintillation detector-based gross radiation monitors. To quantify the fuel performance, release-to-birth ratios (R/B’s) of radioactive fission gases are computed. The gamma-ray spectra acquired by the AGR-1 FPMS are analyzed and used to determine the released activities of specific fission gases, while a dedicated detector provides near-real time count rate information. Isotopic build up and depletion calculations provide the associated isotopic birth rates. This paper highlights the features of the FPMS, encompassing the equipment, methods and measures that enable the calculation of the release-to-birth ratios. Some preliminary results from the AGR-1 experiment are also presented.

  5. Monitoring of leachate quality stored in gas ventilation pipes for evaluating the degree of landfill stabilization.

    PubMed

    Tojo, Yasumasa; Sato, Masahiro; Matsuo, Takayuki; Matsuto, Toshihiko

    2011-01-01

    Monitoring of leachate quality is the essential measure in aftercare for evaluating landfill stabilization. Generally, the most common way of leachate monitoring is executed at the inlet of the leachate treatment facility. However, it does not necessarily reflect the actual state of the site. Thus, methodologies which focus on both the discharge, in order to determine when the post-closure care of the facility should terminate, and on the degree of waste stabilization in the landfill are required. In the present study, monitoring of leachate quality stored in 68 gas ventilation pipes was conducted and the degree of waste stabilization at each location in the landfill was estimated by a statistical approach using the results obtained by monitoring. Leachate characteristics varied significantly for each pipe but seemed to reflect the waste condition of the nearby location. Correlation among the analysed items was quite high. Namely, the difference of leachate quality seemed to be categorized only by the level of concentration but not by the specific characteristics. To confirm this, Euclidean distances of dissimilarity were calculated by multidimensional scaling using six items of leachate quality and temperature. Two factors (thickness of leachate and concentration of total organic carbon (TOC) and electric conductivity (EC)) that distinguish leachate characteristics appeared. To indicate the degree of stabilization by location, the spatial distribution of TOC, total nitrogen (TN), inorganic carbon (IC), and chloride ion were estimated by using the ordinary Kriging methodology. As the result, it was estimated that the concentration of leachate existing within the landfill, especially TN, was higher than the completion criteria for leachate in most parts of the investigated area.

  6. Decision analysis for continuous cover gas monitoring of Ferrocyanide Watch List tanks

    SciTech Connect

    Fowler, K.D.; Graves, R.D.

    1994-07-01

    This document pertains to underground waste storage tanks at the Hanford Site that have been identified to potentially contain a significant amount of ferrocyanide compounds. This document evaluates the need for continuously monitoring the headspace vapors in Ferrocyanide Watch List tanks to detect flammable gases or gases that could indicate the occurrence of a propagating ferrocyanide-nitrate/nitrite reaction. The results of modeling studies and gas monitoring, and sludge sample analyses of actual ferrocyanide tank wastes have indicated no need to continuously monitor the vapor spaces in ferrocyanide tanks. This conclusion is based in part on the following factors: (1) a study performance on waste aging suggests that the ferrocyanide has degraded in the tanks during the more than 35 years of storage; therefore, the ferrocyanide is not present in concentrations that could support an exothermic reaction, also, the moisture present in the waste is sufficient to preclude a self-sustaining (propagating) ferrocyanide-nitrate reaction; (2) evaluation of core sample results from Tank 241-C-109 and Tank 241-C-112 support laboratory studies showing that ferrocyanide has degraded and the fuel concentration in the tanks is considerably lower than postulated by flowsheet simulants; (3) no gases have been identified that would indicate the occurrence of a ferrocyanide nitrate/nitrite reaction; additionally, a self-sustaining ferrocyanide nitrate/nitrite reaction is not possible under current and future planned storage conditions. After reviewing the available information, it is evident that there would be little safety benefit from continuous in-tank vapor monitoring, and the time and commitment of operations schedule and equipment funds are not justified in the face of competing needs.

  7. Zeolites as nanoporous, gas-sensitive materials for in situ monitoring of DeNOx-SCR

    PubMed Central

    Simons, Thomas

    2012-01-01

    Summary In a proof-of-concept study we demonstrate in situ reaction monitoring of DeNOx-SCR on proton-conducting zeolites serving as catalyst and gas sensor at the same time. By means of temperature-dependent impedance spectroscopy we found that the thermally induced NH3 desorption in H-form and in Fe-loaded zeolite H-ZSM-5 follow the same process, while a remarkable difference under DeNOx-SCR reaction conditions was found. The Fe-loaded catalyst shows a significantly lower onset temperature, and time-dependent measurements suggest different SCR reaction mechanisms for the two catalysts tested. These results may help in the development of catalysts for the reduction of NOx emissions and ammonia consumption, and provide insight into the elementary catalytic process promoting a full description of the NH3-SCR reaction system. PMID:23213630

  8. R and D advances in corrosion and crack monitoring for oil and gas lines

    SciTech Connect

    Atherton, D.L.; Czura, W.; Krause, T.W.; Laursen, P.; Mergelas, B.; Hauge, C.

    1996-12-31

    Magnetic Flux Leakage (MFL) inspection techniques for in-line corrosion monitoring of pipelines continue to evolve rapidly. Current R and D is aimed at improving the accuracy and reliability of defect sizing. Major issues are the variability and consequent need to characterize the magnetic properties of the pipes and the effects of line pressure, residual and bending stresses on MFL signals. Magnetic Barkhausen Noise (MBN) measurements are being used to study the stress-induced changes in magnetic anisotropy. Remote Field Eddy Current (RFEC) techniques are being investigated for detection and measurement of stress corrosion cracking in gas pipelines. Anomalous defect source models have improved the detailed explanation of crack defect interactions greatly.

  9. Gas Bubble Trauma Monitoring in the Clearwater River Drainage, Idaho 1998.

    SciTech Connect

    Cochnauer, Tim

    1998-12-01

    Select portions of the Clearwater and North Fork of the Clearwater rivers were electroshocked to estimate the incidence of gas bubble trauma (GBT) occurring in resident fish populations for the spring and summer months of 1998. The study area was divided into four sections and sampled weekly during periods of spill and non-spill from Dworshak Dam. Five thousand five hundred and forty one fish, representing 22 different species, were captured and examined for GBT. Two fish were detected with signs of GBT; exhibiting the lowest incidence of GBT in the last four years (0.04%). Reduced discharge and lower levels of total dissolved gases may have resulted in lower incidence of GBT in the 1998 monitoring period.

  10. Long-term monitoring of soil gas radon and permeability at two reference sites.

    PubMed

    Chen, Jing; Falcomer, Renato; Ly, Jim; Wierdsma, Jessica; Bergman, Lauren

    2008-01-01

    The long-term monitoring of soil radon variations was conducted at two reference sites in Ottawa. The purpose of this study was to determine whether a single soil radon survey could provide a representative soil radon characteristic of the site. Results showed that during the normal field survey period from June to September in Canada, a single field survey with multiple measurements of soil gas radon concentrations at a depth of 80 cm can characterise the soil radon level of a site within a deviation of +/-30%. Direct in situ soil permeability measurements exhibited, however, large variations even within an area of only 10 x 10 m(2). Considering such large variations and the weight of the equipment, soil permeability can be determined by direct measurements whenever possible or by other qualitative evaluation methods for sites that are hard to access with heavy equipment.

  11. Barometric gas transport along geologic faults and its application to nuclear test-ban monitoring

    SciTech Connect

    Carrigan, C.R.; Heinle, R.A.; Hudson, G.B.; Nitao, J.J.

    1996-10-01

    Nuclear explosions produce unique but rapidly decaying radionuclide gases that potentially can be used in the context of a test-ban monitoring program to identify clandestine underground testing activity. To evaluate the upward transport of such gases from an underground explosion, two, non-radioactive gas tracers, spanning a 49-fold difference in species mass, were released in a 400-m-deep, chemical explosive detonation. The more massive tracer was first detected on a fault 50 days following the detonation while the other tracer was detected 375 days after release. Models indicate that both the time scale of arrival and chromatographic behavior of transport are characteristic of barometrically induced flow in a fracture- matrix regime. For a 1-kiloton fission explosion, simulations predict that short-lived isotopes of argon and xenon would be detectable on nearby geologic faults.

  12. Air Pollution Monitoring and Use of Nanotechnology Based Solid State Gas Sensors in Greater Cairo Area, Egypt

    NASA Astrophysics Data System (ADS)

    Ramadan, A. B. A.

    Air pollution is a serious problem in thickly populated and industrialized areas in Egypt, especially in greater Cairo area. Economic growth and industrialization are proceeding at a rapid pace, accompanied by increasing emissions of air polluting sources. Furthermore, though the variety and quantities of polluting sources have increased dramatically, the development of a suitable method for monitoring the pollution causing sources has not followed at the same pace. Environmental impacts of air pollutants have impact on public health, vegetation, material deterioration etc. To prevent or minimize the damage caused by atmospheric pollution, suitable monitoring systems are urgently needed that can rapidly and reliably detect and quantify polluting sources for monitoring by regulating authorities in order to prevent further deterioration of the current pollution levels. Consequently, it is important that the current real-time air quality monitoring system, controlled by the Egyptian Environmental Affairs Agency (EEAA), should be adapted or extended to aid in alleviating this problem. Nanotechnology has been applied to several industrial and domestic fields, for example, applications for gas monitoring systems, gas leak detectors in factories, fire and toxic gas detectors, ventilation control, breath alcohol detectors, and the like. Here we report an application example of studying air quality monitoring based on nanotechnology `solid state gas sensors'. So as to carry out air pollution monitoring over an extensive area, a combination of ground measurements through inexpensive sensors and wireless GIS will be used for this purpose. This portable device, comprising solid state gas sensors integrated to a Personal Digital Assistant (PDA) linked through Bluetooth communication tools and Global Positioning System (GPS), will allow rapid dissemination of information on pollution levels at multiple sites simultaneously.

  13. Fission Product Monitoring and Release Data for the Advanced Gas Reactor -1 Experiment

    SciTech Connect

    Dawn M. Scates; John B. Walter; Jason M. Harp; Mark W. Drigert; Edward L. Reber

    2010-10-01

    The AGR-1 experiment is a fueled multiple-capsule irradiation experiment that was irradiated in the Advanced Test Reactor (ATR) from December 26, 2006 until November 6, 2009 in support of the Very High Temperature Reactor (VHTR) Technology Development Office (TDO) Fuel Development and Qualification program. An important measure of the fuel performance is the quantification of the fission product releases over the duration of the experiment. To provide this data for the inert fission gasses(Kr and Xe), a fission product monitoring system (FPMS) was developed and implemented to monitor the individual capsule effluents for the radioactive species. The FPMS continuously measured the concentrations of various krypton and xenon isotopes in the sweep gas from each AGR-1 capsule to provide an indicator of fuel irradiation performance. Spectrometer systems quantified the concentrations of Kr-85m, Kr-87, Kr-88, Kr-89, Kr-90, Xe-131m, Xe-133, Xe 135, Xe 135m, Xe-137, Xe-138, and Xe-139 accumulated over repeated eight hour counting intervals.-. To determine initial fuel quality and fuel performance, release activity for each isotope of interest was derived from FPMS measurements and paired with a calculation of the corresponding isotopic production or birthrate. The release activities and birthrates were combined to determine Release-to-Birth ratios for the selected nuclides. R/B values provide indicators of initial fuel quality and fuel performance during irradiation. This paper presents a brief summary of the FPMS, the release to birth ratio data for the AGR-1 experiment and preliminary comparisons of AGR-1 experimental fuels data to fission gas release models.

  14. Expected trace gas and aerosol retrieval accuracy of the Geostationary Environment Monitoring Spectrometer

    NASA Astrophysics Data System (ADS)

    Jeong, U.; Kim, J.; Liu, X.; Lee, K. H.; Chance, K.; Song, C. H.

    2015-12-01

    The predicted accuracy of the trace gases and aerosol retrievals from the geostationary environment monitoring spectrometer (GEMS) was investigated. The GEMS is one of the first sensors to monitor NO2, SO2, HCHO, O3, and aerosols onboard geostationary earth orbit (GEO) over Asia. Since the GEMS is not launched yet, the simulated measurements and its precision were used in this study. The random and systematic component of the measurement error was estimated based on the instrument design. The atmospheric profiles were obtained from Model for Ozone And Related chemical Tracers (MOZART) simulations and surface reflectances were obtained from climatology of OMI Lambertian equivalent reflectance. The uncertainties of the GEMS trace gas and aerosol products were estimated based on the OE method using the atmospheric profile and surface reflectance. Most of the estimated uncertainties of NO2, HCHO, stratospheric and total O3 products satisfied the user's requirements with sufficient margin. However, about 26% of the estimated uncertainties of SO2 and about 30% of the estimated uncertainties of tropospheric O3 do not meet the required precision. Particularly the estimated uncertainty of SO2 is high in winter, when the emission is strong in East Asia. Further efforts are necessary in order to improve the retrieval accuracy of SO2 and tropospheric O3 in order to reach the scientific goal of GEMS. Random measurement error of GEMS was important for the NO2, SO2, and HCHO retrieval, while both the random and systematic measurement errors were important for the O3 retrievals. The degree of freedom for signal of tropospheric O3 was 0.8 ± 0.2 and that for stratospheric O3 was 2.9 ± 0.5. The estimated uncertainties of the aerosol retrieval from GEMS measurements were predicted to be lower than the required precision for the SZA range of the trace gas retrievals.

  15. Plant growth chamber M design

    NASA Technical Reports Server (NTRS)

    Prince, R. P.; Knott, W. M.

    1986-01-01

    Crop production is just one of the many processes involved in establishing long term survival of man in space. The benefits of integrating higher plants into the overall plan was recognized early by NASA through the Closed Ecological Life Support System (CELSS) program. The first step is to design, construct, and operate a sealed (gas, liquid, and solid) plant growth chamber. A 3.6 m diameter by 6.7 m high closed cylinder (previously used as a hypobaric vessel during the Mercury program) is being modified for this purpose. The chamber is mounted on legs with the central axis vertical. Entrance to the chamber is through an airlock. This chamber will be devoted entirely to higher plant experimentation. Any waste treatment, food processing or product storage studies will be carried on outside of this chamber. Its primary purpose is to provide input and output data on solids, liquids, and gases for single crop species and multiple species production using different nutrient delivery systems.

  16. Multiple complementary gas distribution assemblies

    DOEpatents

    Ng, Tuoh-Bin; Melnik, Yuriy; Pang, Lily L; Tuncel, Eda; Nguyen, Son T; Chen, Lu

    2016-04-05

    In one embodiment, an apparatus includes a first gas distribution assembly that includes a first gas passage for introducing a first process gas into a second gas passage that introduces the first process gas into a processing chamber and a second gas distribution assembly that includes a third gas passage for introducing a second process gas into a fourth gas passage that introduces the second process gas into the processing chamber. The first and second gas distribution assemblies are each adapted to be coupled to at least one chamber wall of the processing chamber. The first gas passage is shaped as a first ring positioned within the processing chamber above the second gas passage that is shaped as a second ring positioned within the processing chamber. The gas distribution assemblies may be designed to have complementary characteristic radial film growth rate profiles.

  17. Development and testing of a prototype modular tritium and carbon-14 gas environmental monitoring system

    SciTech Connect

    Phillips, H.; Dean, J.; Perrie, L.; Sephton, J.; Parisot, M.

    2015-03-15

    Increasing quantities of radioactive waste are being placed into storage facilities. Many of the waste products contain organic materials which may undergo degradation leading to the release of tritium and carbon-14 species into waste containers and potentially into the environment. Monitoring for radioactive gas releases are required for environmental regulatory compliance and for radiation protection of facility workers. Research is currently being undertaken at the National Physical Laboratory (NPL) as part of a European Metrology Research Programme (EMRP) project MetroRWM to adapt and automate existing environmental sampling techniques for tritium and carbon-14 species. An innovative modular system is being developed which will lead to the introduction of an on-site small scale system capable of gas collection, liquid scintillation sample preparation and measurement. This paper outlines the evaluation of a liquid scintillation system that has been performed to date using active solutions of spiked trapping medium of similar activity concentrations to those anticipated in a waste repository. This system will operate using pre-set conditions for quench and luminescence derived from these and subsequent trials, unlike most other counters for which corrections for these phenomena are applied post measurement. (authors)

  18. Mobile monitoring of fugitive methane emissions from natural gas consumer industries

    NASA Astrophysics Data System (ADS)

    Zhou, X.; Albertson, J. D.; Gaylord, A.; von Fischer, J.; Rudek, J.; Thoma, E. D.

    2015-12-01

    Natural gas is used as a feedstock for major industrial processes, such as ammonia and fertilizer production. However, fugitive methane emissions from many major end-use sectors of the natural gas supply chain have not been quantified yet. This presentation introduces new tools for estimating emission rates from mobile methane measurements, and examines results from recent field measurements conducted downwind of several industrial plants using a specialized vehicle equipped with fast response methane sensor. Using these data along with local meteorological data measured by a 3-D sonic anemometer, a Bayesian approach is applied to probabilistically infer methane emission rates based on a modified Gaussian dispersion model. Source rates are updated recursively with repeated traversals of the downwind methane plume when the vehicle was circling around the targeted facilities. Data from controlled tracer release experiments are presented and used to validate the approach. With access via public roads, this mobile monitoring method is able to quickly assess the emission strength of facilities along the sensor path. This work is developing the capacity for efficient regional coverage of potential methane emission rates in support of leak detection and mitigation efforts.

  19. Regularities of heat transfer in the gas layers of a steam boiler furnace flame. Part II. Gas layer radiation laws and the procedure for calculating heat transfer in furnaces, fire boxes, and combustion chambers developed on the basis of these laws

    NASA Astrophysics Data System (ADS)

    Makarov, A. N.

    2014-10-01

    The article presents the results stemming from the scientific discovery of laws relating to radiation from the gas layers generated during flame combustion of fuel and when electric arc burns in electric-arc steel-melting furnaces. The procedure for calculating heat transfer in electric-arc and torch furnaces, fire-boxes, and combustion chambers elaborated on the basis of this discovery is described.

  20. Hierarchical leak detection and localization method in natural gas pipeline monitoring sensor networks.

    PubMed

    Wan, Jiangwen; Yu, Yang; Wu, Yinfeng; Feng, Renjian; Yu, Ning

    2012-01-01

    In light of the problems of low recognition efficiency, high false rates and poor localization accuracy in traditional pipeline security detection technology, this paper proposes a type of hierarchical leak detection and localization method for use in natural gas pipeline monitoring sensor networks. In the signal preprocessing phase, original monitoring signals are dealt with by wavelet transform technology to extract the single mode signals as well as characteristic parameters. In the initial recognition phase, a multi-classifier model based on SVM is constructed and characteristic parameters are sent as input vectors to the multi-classifier for initial recognition. In the final decision phase, an improved evidence combination rule is designed to integrate initial recognition results for final decisions. Furthermore, a weighted average localization algorithm based on time difference of arrival is introduced for determining the leak point's position. Experimental results illustrate that this hierarchical pipeline leak detection and localization method could effectively improve the accuracy of the leak point localization and reduce the undetected rate as well as false alarm rate.

  1. Tunable Diode Laser Sensors to Monitor Temperature and Gas Composition in High-Temperature Coal Gasifiers

    SciTech Connect

    Hanson, Ronald; Whitty, Kevin

    2014-12-01

    The integrated gasification combined cycle (IGCC) when combined with carbon capture and storage can be one of the cleanest methods of extracting energy from coal. Control of coal and biomass gasification processes to accommodate the changing character of input-fuel streams is required for practical implementation of integrated gasification combined-cycle (IGCC) technologies. Therefore a fast time-response sensor is needed for real-time monitoring of the composition and ideally the heating value of the synthesis gas (here called syngas) as it exits the gasifier. The goal of this project was the design, construction, and demonstration an in situ laserabsorption sensor to monitor multiple species in the syngas output from practical-scale coal gasifiers. This project investigated the hypothesis of using laser absorption sensing in particulateladen syngas. Absorption transitions were selected with design rules to optimize signal strength while minimizing interference from other species. Successful in situ measurements in the dusty, high-pressure syngas flow were enabled by Stanford’s normalized and scanned wavelength modulation strategy. A prototype sensor for CO, CH4, CO2, and H2O was refined with experiments conducted in the laboratory at Stanford University, a pilot-scale at the University of Utah, and an engineering-scale gasifier at DoE’s National Center for Carbon Capture with the demonstration of a prototype sensor with technical readiness level 6 in the 2014 measurement campaign.

  2. Real-time sensing and monitoring in robotic gas metal arc welding

    NASA Astrophysics Data System (ADS)

    Wu, C. S.; Gao, J. Q.; Hu, J. K.

    2007-01-01

    A real-time monitoring system is developed for detecting abnormal conditions in robotic gas metal arc welding. The butt-joint test pieces with simulated large gaps are used to intentionally introduce step disturbance of welding conditions. During the welding process, the welding voltage and current signals are sampled and processed on-line to extract the characteristic information reflecting the process quality. After the first statistical processing, it is found that seven statistical parameters (the mean, standard deviation, coefficient of variance and kurtosis of welding voltage; the mean, coefficient of variance and kurtosis of welding current) show variations during the step disturbance. Through the second statistical processing of the means of the welding voltage for subgroups of continuous measurement, the statistical control chart is obtained, and an SPC (statistical process control)-based on-line identifying method is developed. Ten robotic welding experiments are conducted to verify the real-time monitoring system. It is found that the correct identification rates for normal and abnormal welding conditions are 100% and 95%, respectively.

  3. Hierarchical Leak Detection and Localization Method in Natural Gas Pipeline Monitoring Sensor Networks

    PubMed Central

    Wan, Jiangwen; Yu, Yang; Wu, Yinfeng; Feng, Renjian; Yu, Ning

    2012-01-01

    In light of the problems of low recognition efficiency, high false rates and poor localization accuracy in traditional pipeline security detection technology, this paper proposes a type of hierarchical leak detection and localization method for use in natural gas pipeline monitoring sensor networks. In the signal preprocessing phase, original monitoring signals are dealt with by wavelet transform technology to extract the single mode signals as well as characteristic parameters. In the initial recognition phase, a multi-classifier model based on SVM is constructed and characteristic parameters are sent as input vectors to the multi-classifier for initial recognition. In the final decision phase, an improved evidence combination rule is designed to integrate initial recognition results for final decisions. Furthermore, a weighted average localization algorithm based on time difference of arrival is introduced for determining the leak point’s position. Experimental results illustrate that this hierarchical pipeline leak detection and localization method could effectively improve the accuracy of the leak point localization and reduce the undetected rate as well as false alarm rate. PMID:22368464

  4. Self-tuning method for monitoring the density of a gas vapor component using a tunable laser

    DOEpatents

    Hagans, Karla; Berzins, Leon; Galkowski, Joseph; Seng, Rita

    1996-01-01

    The present invention relates to a vapor density monitor and laser atomic absorption spectroscopy method for highly accurate, continuous monitoring of vapor densities, composition, flow velocity, internal and kinetic temperatures and constituent distributions. The vapor density monitor employs a diode laser, preferably of an external cavity design. By using a diode laser, the vapor density monitor is significantly less expensive and more reliable than prior art vapor density monitoring devices. In addition, the compact size of diode lasers enables the vapor density monitor to be portable. According to the method of the present invention, the density of a component of a gas vapor is calculated by tuning the diode laser to a frequency at which the amount of light absorbed by the component is at a minimum or a maximum within about 50 MHz of that frequency. Laser light from the diode laser is then transmitted at the determined frequency across a predetermined pathlength of the gas vapor. By comparing the amount of light transmitted by the diode laser to the amount of light transmitted after the laser light passes through the gas vapor, the density of the component can be determined using Beer's law.

  5. Self-tuning method for monitoring the density of a gas vapor component using a tunable laser

    DOEpatents

    Hagans, K.; Berzins, L.; Galkowski, J.; Seng, R.

    1996-08-27

    The present invention relates to a vapor density monitor and laser atomic absorption spectroscopy method for highly accurate, continuous monitoring of vapor densities, composition, flow velocity, internal and kinetic temperatures and constituent distributions. The vapor density monitor employs a diode laser, preferably of an external cavity design. By using a diode laser, the vapor density monitor is significantly less expensive and more reliable than prior art vapor density monitoring devices. In addition, the compact size of diode lasers enables the vapor density monitor to be portable. According to the method of the present invention, the density of a component of a gas vapor is calculated by tuning the diode laser to a frequency at which the amount of light absorbed by the component is at a minimum or a maximum within about 50 MHz of that frequency. Laser light from the diode laser is then transmitted at the determined frequency across a predetermined pathlength of the gas vapor. By comparing the amount of light transmitted by the diode laser to the amount of light transmitted after the laser light passes through the gas vapor, the density of the component can be determined using Beer`s law. 6 figs.

  6. Advanced online monitoring of cell culture off-gas using proton transfer reaction mass spectrometry.

    PubMed

    Schmidberger, Timo; Gutmann, Rene; Bayer, Karl; Kronthaler, Jennifer; Huber, Robert

    2014-01-01

    Mass spectrometry has been frequently applied to monitor the O₂ and CO₂ content in the off-gas of animal cell culture fermentations. In contrast to classical mass spectrometry the proton transfer reaction mass spectrometry (PTR-MS) provides additional information of volatile organic compounds by application of a soft ionization technology. Hence, the spectra show less fragments and can more accurately assigned to particular compounds. In order to discriminate between compounds of non-metabolic and metabolic origin cell free experiments and fed-batch cultivations with a recombinant CHO cell line were conducted. As a result, in total eight volatiles showing high relevance to individual cultivation or cultivation conditions could be identified. Among the detected compounds methanethiol, with a mass-to-charge ratio of 49, qualifies as a key candidate in process monitoring due to its strong connectivity to lactate formation. Moreover, the versatile and complex data sets acquired by PTR MS provide a valuable resource for statistical modeling to predict non direct measurable parameters. Hence, partial least square regression was applied to the complete spectra of volatiles measured and important cell culture parameters such as viable cell density estimated (R²  = 0.86). As a whole, the results of this study clearly show that PTR-MS provides a powerful tool to improve bioprocess-monitoring for mammalian cell culture. Thus, specific volatiles emitted by cells and measured online by the PTR-MS and complex variables gained through statistical modeling will contribute to a deeper process understanding in the future and open promising perspectives to bioprocess control.

  7. Soil-gas radon concentration monitoring in an active granite quarry from Central Portugal

    NASA Astrophysics Data System (ADS)

    Neves, Luís.; Barbosa, Susana; Pereira, Alcides; Aumento, Fabrizio

    2010-05-01

    This study was carried out in an active quarry located nearby the town of Nelas (Central Portugal), with the primary objective of assessing the effect of regular explosions on soil-gas radon concentrations. Here, a late-orogenic Hercynian porphyritic biotite granite occurs and is exploited for the production of high quality aggregates for different building purposes. This granite is part of the Beiras batholiths, being a geochemically moderately evolved rock, slightly peraluminous, and widely known by the frequent occurrence of associated uranium mineralizations. In fact, more than 4000t of U3O8 was produced from 60 mines of the Beiras region in the last century, over a wide area of more than 10.000 km2, and thousands of anomalies related with the local accumulation of uranium in fault filling materials, metasedimentary enclaves and doleritic veins were recognized during prospecting works. The heterogeneity of uranium distribution in this rock is reflected at the test site; indeed, a gamma ray survey shows that some of the faults that occur in the quarry are slightly mineralized. A total of 7 radon monitoring stations were implemented in the quarry, at a typical depth comprised between 1 and 2 meters, in holes drilled for the purpose. Aware RM-70 pancake GM detectors were used, sensitive to alpha, beta and gamma/X-rays above 10 keV, connected to palmtop computers for data registration (1 minute interval) and power supplied by batteries. Monitoring was carried out during 6 months, in Spring/Summer conditions and the exact time of each explosion was registered manually. Several problems of data loss and power supply affected the stations during the experiment, leading to discontinuities in the records. Still the available data showed important differences in the soil-gas radon concentrations between stations, which can be explained by the heterogeneity of uranium distribution in the rock and increased local permeability. Furthermore, all stations showed a clear daily

  8. Design of an Online Fission Gas Monitoring System for Post-irradiation Examination Heating Tests of Coated Fuel Particles for High-Temperature Gas-Cooled Reactors

    SciTech Connect

    Dawn Scates

    2010-10-01

    A new Fission Gas Monitoring System (FGMS) has been designed at the Idaho National Laboratory (INL) for use of monitoring online fission gas-released during fuel heating tests. The FGMS will be used with the Fuel Accident Condition Simulator (FACS) at the Hot Fuels Examination Facility (HFEF) located at the Materials and Fuels Complex (MFC) within the INL campus. Preselected Advanced Gas Reactor (AGR) TRISO (Tri-isotropic) fuel compacts will undergo testing to assess the fission product retention characteristics under high temperature accident conditions. The FACS furnace will heat the fuel to temperatures up to 2,000ºC in a helium atmosphere. Released fission products such as Kr and Xe isotopes will be transported downstream to the FGMS where they will accumulate in cryogenically cooledcollection traps and monitored with High Purity Germanium (HPGe) detectors during the heating process. Special INL developed software will be used to monitor the accumulated fission products and will report data in near real-time. These data will then be reported in a form that can be readily available to the INL reporting database. This paper describes the details of the FGMS design, the control and acqusition software, system calibration, and the expected performance of the FGMS. Preliminary online data may be available for presentation at the High Temperature Reactor (HTR) conference.

  9. Application network for monitoring of green house gas emission from lithosphere in Khibina territories

    NASA Astrophysics Data System (ADS)

    Asavin, Alex; Nivin, Valentin; Litvinov, Artur; Chesalova, Elena; Baskov, Sergey

    2015-04-01

    The aim of project is to estimate the contribution of lithospheric flue gas emission of gases CH4, CO2, H2 in the general composition of atmospheric pollution of Arctic zone. The main task is organization of the ecological monitoring in the area of exploitation of large apatite and rare earth ore deposit from Khibine massive on the base of modern WSN (wireless sensor network) technologies. Application network consist from sensors of gas H2, CH4, CO2, complex autonomous equipment for measurement temperature, pressure, humidity and network of telecommunications (used ZigBee protocol). Our project offer technical decisions for experimentally-methodical monitoring network on the base of WSN and the high-sensitive sensors of hydrogen and methane, software and electronic equipment with a transmitter network. This work is the first project in Russia. The advantages of this technology is autonomous work (to several months and more), high-frequency programmable measurement of gas sensor, low cost (on one node of network), possibility to connect to one node of supervision a several types of sensors. And as a result is complex monitoring of environment. It has long been known that the pollution in Arctic Khibine and Lovosero region contains unusually high levels of hydrocarbon gases (HCG) [Petersilie,1964]. The presence of these gases has a number of practical implications and it is therefore important to understand their source and distribution. Among alkaline intrusive complexes with high (for magmatic rocks) concentrations of hydrocarbon and hydrogen- hydrocarbon gases occluded as fluid inclusions in minerals. The Khibina and Lovozero massives are well known, as region of spontaneous emissions of these gases from lithosphere [Khitarov et al., 1979; Ikorskii et al., 1992; Beeskow 2007; Nivin 2005, 2009]. The presence of the HCG, however, raises a number of questions and possibilities. It is unclear how homogeneously the HCG are distributed through the complex? What is the

  10. Silicone Tubes - Simple and Effective Tools for Gas Extraction and Monitoring in the Course of Hydrate Dissociation

    NASA Astrophysics Data System (ADS)

    Strauch, B.; Schicks, J. M.; Zimmer, M.

    2015-12-01

    The in situ dissociation of gas hydrate is prerequisite for the commercial recovery of natural gas from hydrate deposits. We examined different methods such as depressurization, thermal stimulation and distortion of the chemical equilibrium by carbon dioxide sequestration for methane gas production from hydrates within our Large Scale reservoir simulator LARS in a pilot plant scale. Within this setup, thin-walled (0.8 mm) silicon tubes are utilized for in situ gas capture. They function as membranes for the extraction of methane gas, leaving sediment and brine behind. The gas capture via silicone tube membranes is, due to their robust nature, reliably applicable in remote and rough areas. First tests show that, driven by the transmembrane pressure difference, the methane flux through these membranes is about 1 mL per minute per cm² membrane surface at a reservoir pressure of about 20 MPa. This is in good agreement with values reported in the literature [e.g. 2]. The operation of the membranes as a simple capture tool for the released methane from a hydrate deposit is therefore considered as feasible. Furthermore, silicone tube membranes are suitable for the quantification of free and dissolved gas volumes. For the monitoring of spatial and temporal gas distribution, LARS has been equipped with several silicone membranes at various locations. They have been utilized to monitor the progress of hydrate formation and decomposition and show that inhomogeneous gas distributions within the reservoir are detectable and terminable. The quantification of carbon dioxide/methane gas ratios during exchange experiments, however, is due to differences in water solubility and permeation rates of the gas species challenging. The study assesses the capability and limits of silicone tubes as membranes for gas extraction and as a tool to monitor gas distribution and composition in the course of hydrate dissociation experiments. [1] Merkel, T.C.; Bodnar, V.I.; Nagai, K.; Freeman, B

  11. Field Test Report: NETL Portable Raman Gas Composition Monitor - Initial Industrial tests at NETL and General Electric (GE)

    SciTech Connect

    Michael, Buric; Jessica, Mullen; Steven, Woodruff; Ben, Chorpening

    2012-02-24

    NETL has developed new technology which enables the use of Raman spectroscopy in the real-time measurement of gas mixtures. This technology uses a hollow reflective metal-lined capillary waveguide as a gas sampling cell which contains the sample gas, and efficiently collects optical Raman scattering from the gas sample, for measurement with a miniature spectrometer. The result is an optical Raman “fingerprint” for each gas which is tens or hundreds of times larger than that which can be collected with conventional free-space optics. In this manner, the new technology exhibits a combination of measurement speed and accuracy which is unprecedented for spontaneous Raman measurements of gases. This makes the system especially well-suited to gas turbine engine control based on a-priori measurement of incoming fuel composition. The system has been developed to produce a measurement of all of the common components of natural gas, including the lesser nitrogen, oxygen, carbon-dioxide, and carbon monoxide diluents to better than 1% concentration accuracy each second. The objective of this task under CRADA 10-N100 was to evaluate the capability of a laser Raman capillary gas sensor for combustion fuels. A portable version of the Raman gas sensor, constructed at NETL, was used for field-trials conducted in a cooperative research effort at a GE facility. Testing under the CRADA was performed in 5 parts. Parts 1-4 were successful in testing of the Raman Gas Composition Monitor with bottled calibration gases, and in continuous monitoring of several gas streams at low pressure, in comparison with an online mass spectrometer. In part 5, the Raman Gas Composition Monitor was moved outdoors for testing with high pressure gas supplies. Some difficulties were encountered during industrial testing including the condensation of heavy hydrocarbons inside the sample cell (in part 5), communication with the GE data collection system, as well as some drift in the optical noise

  12. Development and evaluation of a transportable fast gas chromatograph for the monitoring of organic vapors in air

    SciTech Connect

    Gonzalez, J.A.; Levine, S.P.; Berkley, R.E.

    1993-01-01

    Gas chromatography has the potential to be a real-time or near real-time monitoring method for organics in air. A transportable fast GC with FID/ECD and PID/ECD configurations has been developed. Preliminary evaluation has shown that all design features and improvements of the instrument worked successfully.

  13. Mimicking Mars: A vacuum simulation chamber for testing environmental instrumentation for Mars exploration

    SciTech Connect

    Sobrado, J. M. Martín-Soler, J.; Martín-Gago, J. A.

    2014-03-15

    We have built a Mars environmental simulation chamber, designed to test new electromechanical devices and instruments that could be used in space missions. We have developed this environmental system aiming at validating the meteorological station Rover Environment Monitoring Station of NASA's Mars Science Laboratory mission currently installed on Curiosity rover. The vacuum chamber has been built following a modular configuration and operates at pressures ranging from 1000 to 10{sup −6} mbars, and it is possible to control the gas composition (the atmosphere) within this pressure range. The device (or sample) under study can be irradiated by an ultraviolet source and its temperature can be controlled in the range from 108 to 423 K. As an important improvement with respect to other simulation chambers, the atmospheric gas into the experimental chamber is cooled at the walls by the use of liquid-nitrogen heat exchangers. This chamber incorporates a dust generation mechanism designed to study Martian-dust deposition while modifying the conditions of temperature, and UV irradiated.

  14. Mimicking Mars: a vacuum simulation chamber for testing environmental instrumentation for Mars exploration.

    PubMed

    Sobrado, J M; Martín-Soler, J; Martín-Gago, J A

    2014-03-01

    We have built a Mars environmental simulation chamber, designed to test new electromechanical devices and instruments that could be used in space missions. We have developed this environmental system aiming at validating the meteorological station Rover Environment Monitoring Station of NASA's Mars Science Laboratory mission currently installed on Curiosity rover. The vacuum chamber has been built following a modular configuration and operates at pressures ranging from 1000 to 10(-6) mbars, and it is possible to control the gas composition (the atmosphere) within this pressure range. The device (or sample) under study can be irradiated by an ultraviolet source and its temperature can be controlled in the range from 108 to 423 K. As an important improvement with respect to other simulation chambers, the atmospheric gas into the experimental chamber is cooled at the walls by the use of liquid-nitrogen heat exchangers. This chamber incorporates a dust generation mechanism designed to study Martian-dust deposition while modifying the conditions of temperature, and UV irradiated.

  15. CONTINUOUS ROTATION SCATTERING CHAMBER

    DOEpatents

    Verba, J.W.; Hawrylak, R.A.

    1963-08-01

    An evacuated scattering chamber for use in observing nuclear reaction products produced therein over a wide range of scattering angles from an incoming horizontal beam that bombards a target in the chamber is described. A helically moving member that couples the chamber to a detector permits a rapid and broad change of observation angles without breaching the vacuum in the chamber. Also, small inlet and outlet openings are provided whose size remains substantially constant. (auth)

  16. Advanced Small Rocket Chambers. Basic Program and Option 2: Fundamental Processes and Material Evaluation

    NASA Technical Reports Server (NTRS)

    Jassowski, Donald M.

    1993-01-01

    Propellants, chamber materials, and processes for fabrication of small high performance radiation cooled liquid rocket engines were evaluated to determine candidates for eventual demonstration in flight-type thrusters. Both storable and cryogenic propellant systems were considered. The storable propellant systems chosen for further study were nitrogen tetroxide oxidizer with either hydrazine or monomethylhydrazine as fuel. The cryogenic propellants chosen were oxygen with either hydrogen or methane as fuel. Chamber material candidates were chemical vapor deposition (CVD) rhenium protected from oxidation by CVD iridium for the chamber hot section, and film cooled wrought platinum-rhodium or regeneratively cooled stainless steel for the front end section exposed to partially reacted propellants. Laser diagnostics of the combustion products near the hot chamber surface and measurements at the surface layer were performed in a collaborative program at Sandia National Laboratories, Livermore, CA. The Material Sample Test Apparatus, a laboratory system to simulate the combustion environment in terms of gas and material temperature, composition, and pressure up to 6 Atm, was developed for these studies. Rocket engine simulator studies were conducted to evaluate the materials under simulated combustor flow conditions, in the diagnostic test chamber. These tests used the exhaust species measurement system, a device developed to monitor optically species composition and concentration in the chamber and exhaust by emission and absorption measurements.

  17. Evaluation and Application of a Solid Adsorbent Method for Monitoring Exposure to Volatile Organic Compounds from Oil and Gas Operations.

    NASA Astrophysics Data System (ADS)

    Smith, K. R.; Helmig, D.; Thompson, C. R.; Wang, W.; Terrell, R. M.; Lewis, A. C.

    2014-12-01

    Residential communities are being increasingly impacted by emissions from oil and gas development and this has driven the need for simple, effective, and low-cost methods for air quality monitoring. Primary emissions from oil and gas production consist of volatile organic compounds (VOCs) ranging from the short chain alkanes and alkenes to aromatic and semi-volatile species; many of these are a concern from both an air quality and public health viewpoint, as they can lead to local ozone pollution and increased risk of cancer or respiratory illness. The fate of hydrocarbons once in the atmosphere is ultimately oxidation through to CO2 and water, adding to the greenhouse gas burden. Measurement techniques that are capable of identifying and quantifying the full range of primary emissions of concern are required to assess community exposure to air toxics and to better inform residents, as well as local and state legislators. Here, we present evaluation of a low-cost air monitoring technique using stainless steel diffusion cartridges containing multiple solid adsorbents. Over the course of a three-month period in summer of 2014, cartridges were deployed at five monitoring sites located around Boulder County in the Northern Colorado Front Range, and exposed to ambient air for periods of up to four days along with concurrent sampling using stainless steel SUMMA canisters. Samples collected with both methods were subsequently analyzed for VOCs by GC-FID and the results were compared to determine the accuracy and precision of the diffusion cartridge method. Results of this evaluation show that the diffusion cartridge method has the potential to be a simple and low-cost solution for widespread exposure monitoring in communities near oil and gas development regions. Such measurements may also provide supporting evidence on wider effects on greenhouse gas emissions from oil and gas development operations.

  18. Monitoring of a gas reservoir in Western Siberia through SqueeSAR

    NASA Astrophysics Data System (ADS)

    Rucci, Alessio; Ferretti, Alessandro; Fokker, Peter A.; Jager, Johan; Lou, Sten

    2014-05-01

    The success of surface movement monitoring using InSAR is critically dependent on the coherence of the radar signal though time and over space. As a result, rural areas are more difficult to monitor with this technology than are areas with a lot of infrastructure. The development of advanced algorithms exploiting distributed scatterers, such as SqueeSAR, has improved these possibilities considerably. However, in rural areas covered with varying quantities of snow and ice, it had not yet been possible to demonstrate the applicability of the technology. We performed a study to assess the applicability of InSAR for assessing land movement is Western Siberia, where we chose the area of the Yuznho Russkoye field for a detailed analysis, after a screening using data that involved a number of fields in the vicinity of the Yuznho Russkoye Field. A first evaluation with C-band data ranging from 2004 - 2010 was unsuccessful due to the small number of images. Therefore we investigated the applicability of X-band data. 75 images were available spanning a period spanning May 2012 until July 2013. Within the summer periods when there was no snow coverage, the X-band data showed good coherence. The subsidence during a summer season, however, was not sufficient to make a quantitative comparison between geomechanical predictions and geodetic observations. Including the winter season in the analysis, however, destroyed the coherence and no subsidence signal could be derived. Quite unexpectedly, however, by cutting out the winter season and using the two disconnected summer seasons simultaneously, the coherence re-appeared and a subsidence estimate was established covering the full period. This way, the temporal surface movement could be established as a function of the position in the field. The spatial subsidence distribution was subsequently compared with the expected pattern expected from the location of producing wells and was found to be show a good correlation. Subsidence was

  19. An atmospheric exposure chamber for small animals

    NASA Technical Reports Server (NTRS)

    Glaser, R. M.; Weiss, H. S.; Pitt, J. F.; Grimard, M.

    1982-01-01

    The purpose of this project was to design a long-term environmental exposure chamber for small animals. This chamber is capable of producing hypoxic, normoxic and hyperoxic atmospheres which are closely regulated. The chamber, which is of the recycling type, is fashioned after clear plastic germ-free isolators. Oxygen concentration is set and controlled by a paramagnetic O2 analyzer and a 3-way solenoid valve. In this way either O2 or N2 may be provided to the system by way of negative O2 feedback. Relative humidity is maintained at 40-50 percent by a refrigeration type dryer. Carbon dioxide is absorbed by indicating soda lime. A diaphragm pump continuously circulates chamber gas at a high enough flow rate to prevent buildup of CO2 and humidity. This chamber has been used for numerous studies which involve prolonged exposure of small animals to various O2 concentrations.

  20. Long term monitoring of methane in the atmosphere by multiplex gas chromatography

    NASA Technical Reports Server (NTRS)

    Valentin, Jose R.; Carle, Glenn C.; Phillips, John B.

    1985-01-01

    Methane is of interest in the study of the Earth's atmosphere because of its implication in the future global warming of the surface. This warming is produced by the absorption of infrared energy by trace gases. It has been estimated that in the next 40 to 50 years, methane could contribute 20 to 25 pct. as much atmospheric warming as that expected from carbon dioxide increases. Studies to examine sources, sinks, and cycles of methane will require analytical methods capable of continuous unattended measurement with temporal resolution of an hour or less for weeks at a time. Gas chromatography (GC) is one of the most practical methods available to conduct the analysis of air, but limitations in this technique still exist which can be alleviated with multiplex GC (MGC). MGC is a technique where many samples are pseudo-randomly introduced to the chromatograph without regard to the length of time required for an analysis. The resulting data must then be reduced using computational methods such as cross correlation. In the technique reported, a tube packed with silver oxide was used at the inlet of the GC column to create concentration pulses of methane in a sample stream of air. By using only one carrier, i.e., ambient air, an effective and accurate method to monitor the variations in concentration of methane in the atmosphere over long periods of time was developed. Methane in ambient air was monitored for an eight day period and an interesting temporal variability was found. This work has shown the utility of a relatively simple MGC for the analysis of a real environmental sample.

  1. Formation and migration of Natural Gases: gas composition and isotopes as monitors between source, reservoir and seep

    NASA Astrophysics Data System (ADS)

    Schoell, M.; Etiope, G.

    2015-12-01

    Natural gases form in tight source rocks at temperatures between 120ºC up to 200ºC over a time of 40 to 50my depending on the heating rate of the gas kitchen. Inferring from pyrolysis experiments, gases after primary migration, a pressure driven process, are rich in C2+ hydrocarbons (C2 to C5). This is consistent with gas compositions of oil-associated gases such as in the Bakken Shale which occur in immediate vicinity of the source with little migration distances. However, migration of gases along porous rocks over long distances (up to 200km in the case of the Troll field offshore Norway) changes the gas composition drastically as C2+ hydrocarbons tend to be retained/sequestered during migration of gas as case histories from Virginia and the North Sea will demonstrate. Similar "molecular fractionation" is observed between reservoirs and surface seeps. In contrast to gas composition, stable isotopes in gases are, in general, not affected by the migration process suggesting that gas migration is a steady state process. Changes in isotopic composition, from source to reservoir to surface seeps, is often the result of mixing of gases of different origins. Examples from various gas provinces will support this notion. Natural gas basins provide little opportunity of tracking and identifying gas phase separation. Future research on experimental phase separation and monitoring of gas composition and gas ratio changes e.g. various C2+ compound ratios over C1 or isomer ratios such as iso/n ratios in butane and pentane may be an avenue to develop tracers for phase separation that could possibly be applied to natural systems of retrograde natural condensate fields.

  2. Realtime Gas Emission Monitoring at Hazardous Sites Using a Distributed Point-Source Sensing Infrastructure

    PubMed Central

    Manes, Gianfranco; Collodi, Giovanni; Gelpi, Leonardo; Fusco, Rosanna; Ricci, Giuseppe; Manes, Antonio; Passafiume, Marco

    2016-01-01

    This paper describes a distributed point-source monitoring platform for gas level and leakage detection in hazardous environments. The platform, based on a wireless sensor network (WSN) architecture, is organised into sub-networks to be positioned in the plant’s critical areas; each sub-net includes a gateway unit wirelessly connected to the WSN nodes, hence providing an easily deployable, stand-alone infrastructure featuring a high degree of scalability and reconfigurability. Furthermore, the system provides automated calibration routines which can be accomplished by non-specialized maintenance operators without system reliability reduction issues. Internet connectivity is provided via TCP/IP over GPRS (Internet standard protocols over mobile networks) gateways at a one-minute sampling rate. Environmental and process data are forwarded to a remote server and made available to authenticated users through a user interface that provides data rendering in various formats and multi-sensor data fusion. The platform is able to provide real-time plant management with an effective; accurate tool for immediate warning in case of critical events. PMID:26805832

  3. Realtime Gas Emission Monitoring at Hazardous Sites Using a Distributed Point-Source Sensing Infrastructure.

    PubMed

    Manes, Gianfranco; Collodi, Giovanni; Gelpi, Leonardo; Fusco, Rosanna; Ricci, Giuseppe; Manes, Antonio; Passafiume, Marco

    2016-01-20

    This paper describes a distributed point-source monitoring platform for gas level and leakage detection in hazardous environments. The platform, based on a wireless sensor network (WSN) architecture, is organised into sub-networks to be positioned in the plant's critical areas; each sub-net includes a gateway unit wirelessly connected to the WSN nodes, hence providing an easily deployable, stand-alone infrastructure featuring a high degree of scalability and reconfigurability. Furthermore, the system provides automated calibration routines which can be accomplished by non-specialized maintenance operators without system reliability reduction issues. Internet connectivity is provided via TCP/IP over GPRS (Internet standard protocols over mobile networks) gateways at a one-minute sampling rate. Environmental and process data are forwarded to a remote server and made available to authenticated users through a user interface that provides data rendering in various formats and multi-sensor data fusion. The platform is able to provide real-time plant management with an effective; accurate tool for immediate warning in case of critical events.

  4. A gas chromatography-mass spectrometry method to monitor detergents removal from a membrane protein sample.

    PubMed

    Shi, Chaowei; Han, Fang; Xiong, Ying; Tian, Changlin

    2009-12-01

    In membrane protein biochemical and structural studies, detergents are used to mimic membrane environment and maintain functional, stable conformation of membrane proteins in the absence of lipid bilayers. However, detergent concentration, esp. molar ratio of membrane protein to detergent is usually unknown. Here, a gas chromatography-mass spectrometry selected ion monitoring (GC-MS-SIM) method was developed to quantify four detergents which are frequently used in membrane protein structural studies. To remove excessive detergents, a filtered centrifugation using Centricon tubes was applied. A membrane protein Ig-Beta fragment in four different detergent micelles was exemplified. Detergent concentrations in the upper and lower fraction of the Centricon tube were measured after each round of centrifugation. The results were very consistent to basic properties of detergent micelles in aqueous solvents. Therefore, coupling of GC-MS-SIM and detergent removal by Centricon tubes, detergents concentration, esp. molar ratio of membrane protein to detergent could be controlled, which will expedite membrane protein structural and biochemical studies.

  5. Gas centrifuge enrichment plants inspection frequency and remote monitoring issues for advanced safeguards implementation

    SciTech Connect

    Boyer, Brian David; Erpenbeck, Heather H; Miller, Karen A; Ianakiev, Kiril D; Reimold, Benjamin A; Ward, Steven L; Howell, John

    2010-09-13

    Current safeguards approaches used by the IAEA at gas centrifuge enrichment plants (GCEPs) need enhancement in order to verify declared low enriched uranium (LEU) production, detect undeclared LEU production and detect high enriched uranium (BEU) production with adequate probability using non destructive assay (NDA) techniques. At present inspectors use attended systems, systems needing the presence of an inspector for operation, during inspections to verify the mass and {sup 235}U enrichment of declared cylinders of uranium hexafluoride that are used in the process of enrichment at GCEPs. This paper contains an analysis of how possible improvements in unattended and attended NDA systems including process monitoring and possible on-site destructive analysis (DA) of samples could reduce the uncertainty of the inspector's measurements providing more effective and efficient IAEA GCEPs safeguards. We have also studied a few advanced safeguards systems that could be assembled for unattended operation and the level of performance needed from these systems to provide more effective safeguards. The analysis also considers how short notice random inspections, unannounced inspections (UIs), and the concept of information-driven inspections can affect probability of detection of the diversion of nuclear material when coupled to new GCEPs safeguards regimes augmented with unattended systems. We also explore the effects of system failures and operator tampering on meeting safeguards goals for quantity and timeliness and the measures needed to recover from such failures and anomalies.

  6. A Greenhouse-Gas Information System: Monitoring and Validating Emissions Reporting and Mitigation

    SciTech Connect

    Jonietz, Karl K.; Dimotakis, Paul E.; Walker, Bruce C.

    2011-09-26

    This study and report focus on attributes of a greenhouse-gas information system (GHGIS) needed to support MRV&V needs. These needs set the function of such a system apart from scientific/research monitoring of GHGs and carbon-cycle systems, and include (not exclusively): the need for a GHGIS that is operational, as required for decision-support; the need for a system that meets specifications derived from imposed requirements; the need for rigorous calibration, verification, and validation (CV&V) standards, processes, and records for all measurement and modeling/data-inversion data; the need to develop and adopt an uncertainty-quantification (UQ) regimen for all measurement and modeling data; and the requirement that GHGIS products can be subjected to third-party questioning and scientific scrutiny. This report examines and assesses presently available capabilities that could contribute to a future GHGIS. These capabilities include sensors and measurement technologies; data analysis and data uncertainty quantification (UQ) practices and methods; and model-based data-inversion practices, methods, and their associated UQ. The report further examines the need for traceable calibration, verification, and validation processes and attached metadata; differences between present science-/research-oriented needs and those that would be required for an operational GHGIS; the development, operation, and maintenance of a GHGIS missions-operations center (GMOC); and the complex systems engineering and integration that would be required to develop, operate, and evolve a future GHGIS.

  7. The LIFE Dynamic Chamber System

    NASA Astrophysics Data System (ADS)

    Rhodes, Mark; Kane, Jave; Latkowski, Jeffery; Cook, Andrew; Divol, Laurent; Loosmore, Gwendolen; Scott, Howard; Scullard, Christian; Tabak, Max; Wilks, Scott; Moses, Gregory; Heltemes, Thad; Sacks, Ryan; Pantano, Carlos; Kramer, Richard

    2011-10-01

    Dry-wall IFE designs such as LIFE utilize Xe fill gas to protect the target chamber first wall from x-ray heating and ionic debris. A key question is how cool, settled and clean the Xe must be to permit beam propagation and target transport, and how to reach this state at a 10+ Hz shot repetition rate. Xe is at low density in the target chamber, and purified Xe is reinjected at higher density and lower temperature into the larger outer chamber. Maintenance of this density difference due to blast waves generated by implosion of the target capsules is being assessed with HYDRA and 3D VTF, and possible validation experiments are being investigated. Detailed gas response near the wall is being studied using 3D Miranda. A laboratory-scale theta pinch experiment will study cooling and beam propagation in Xe. This work performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.

  8. A Portable Gas Sensor System for Environmental Monitoring and Malodours Control: Data Assessment of an Experimental Campaign

    NASA Astrophysics Data System (ADS)

    Penza, Michele; Suriano, Domenico; Cassano, Gennaro; Rossi, Riccardo; Alvisi, Marco; Pfister, Valerio; Trizio, Livia; Brattoli, Magda; Amodio, Martino; De Gennaro, Gianluigi

    2011-09-01

    A portable sensor-system based on solid-state gas sensors has been designed and implemented as proof-of-concept for environmental air-monitoring applications, malodours olfactometric control and landfill gas monitoring. Commercial gas sensors and nanotechnology sensors are arranged in a configuration of array for multisensing and multiparameter devices. Wireless sensors at low-cost are integrated to implement a portable and mobile node, that can be used as early-detection system in a distributed sensor network. Real-time and continuous monitoring of hazardous air-contaminants (NO2, CO, PAH, BTEX, etc.) has been performed in field measurements by comparison of chemical analyzers from environmental protection governmental agency (ARPA-Puglia). In addition, experimental campaigns of the integrated portable sensor-system have been realized for assessment of malodours emitted from an urban waste site. The results demonstrate that the sensor-system has a potential capacity for real-time measurements of air-pollutants, malodours from waste site, and control of landfill gas.

  9. Compact Multi-Gas Monitor for Life Support Systems Control in Space: Evaluation Under Realistic Environmental Conditions

    NASA Technical Reports Server (NTRS)

    Alonso, Jesus Delgado; Phillips, Straun; Chullen, Cinda; Mendoza, Edgar

    2014-01-01

    Advanced space life support systems require lightweight, low-power, durable sensors for monitoring critical gas components. A luminescence-based optical flow-through cell to monitor carbon dioxide, oxygen, and humidity has been developed and was demonstrated using bench-top instrumentation under environmental conditions relevant to portable life support systems, including initially pure oxygen atmosphere, temperature range from 50 F to 150 F, and humidity from dry to 100% RH and under conditions of water condensation. This paper presents the most recent progress in the development of this sensor technology. Trace gas contaminants in a space suit, originating from hardware and material off-gassing and crew member metabolism, are from many chemical families. The result is a gas mix much more complex than the pure oxygen fed into the space suit, and this complexity may interfere with gas sensor readings. This paper presents an evaluation of optical sensor performance when exposed to the most significant trace gases reported to be found in space suits. A study of the calibration stability of the sensors is also presented. For that purpose, a profile of temperature, pressure, humidity, and gas composition for the duration of an EVA has been defined, and the performance of sensors operated repeatedly under those conditions has been studied. Finally, this paper presents the first compact readout unit for these optical sensors, designed for the volume, power, and weight restrictions of a PLSS.

  10. Gas chromatograph injection system

    NASA Technical Reports Server (NTRS)

    Pollock, G. E.; Henderson, M. E.; Donaldson, R. W., Jr. (Inventor)

    1975-01-01

    An injection system for a gas chromatograph is described which uses a small injector chamber (available in various configurations). The sample is placed in the chamber while the chamber is not under pressure and is not heated, and there is no chance of leakage caused by either pressure or heat. It is injected into the apparatus by changing the position of a valve and heating the chamber, and is volatilized and swept by a carrier gas into the analysis apparatus.

  11. Quality assurance procedures for environmental control and monitoring in plant growth facilities. Report of the North Central Regional 101 Committee on Growth Chamber Use

    NASA Technical Reports Server (NTRS)

    Tibbitts, T. W. (Principal Investigator)

    1986-01-01

    This report includes procedures for ensuring the quality of the environment provided for plant growth in controlled environment facilities. Biologists and engineers may use these procedures for ensuring quality control during experiments or for ensuring quality control in the design of plant growth facilities. Environmental monitoring prior to and during experiments is included in these procedures. Specific recommendations cover control, acquisition, and calibration for sensor types for the separate parameters of radiation (light), temperature, humidity, carbon dioxide, and air movement.

  12. FEMO, A FLOW AND ENRICHMENT MONITOR FOR VERIFYING COMPLIANCE WITH INTERNATIONAL SAFEGUARDS REQUIREMENTS AT A GAS CENTRIFUGE ENRICHMENT FACILITY

    SciTech Connect

    Gunning, John E; Laughter, Mark D; March-Leuba, Jose A

    2008-01-01

    A number of countries have received construction licenses or are contemplating the construction of large-capacity gas centrifuge enrichment plants (GCEPs). The capability to independently verify nuclear material flows is a key component of international safeguards approaches, and the IAEA does not currently have an approved method to continuously monitor the mass flow of 235U in uranium hexafluoride (UF6) gas streams. Oak Ridge National Laboratory is investigating the development of a flow and enrichment monitor, or FEMO, based on an existing blend-down monitoring system (BDMS). The BDMS was designed to continuously monitor both 235U mass flow and enrichment of UF6 streams at the low pressures similar to those which exists at GCEPs. BDMSs have been installed at three sites-the first unit has operated successfully in an unattended environment for approximately 10 years. To be acceptable to GCEP operators, it is essential that the instrument be installed and maintained without interrupting operations. A means to continuously verify flow as is proposed by FEMO will likely be needed to monitor safeguards at large-capacity plants. This will enable the safeguards effectiveness that currently exists at smaller plants to be maintained at the larger facilities and also has the potential to reduce labor costs associated with inspections at current and future plants. This paper describes the FEMO design requirements, operating capabilities, and development work required before field demonstration.

  13. 40 CFR 60.107a - Monitoring of emissions and operations for fuel gas combustion devices.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... this section will be considered inherently low in sulfur content. (i) Pilot gas for heaters and flares... produced in process units that are intolerant to sulfur contamination, such as fuel gas streams produced...

  14. 40 CFR 60.107a - Monitoring of emissions and operations for fuel gas combustion devices.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... this section will be considered inherently low in sulfur content. (i) Pilot gas for heaters and flares... produced in process units that are intolerant to sulfur contamination, such as fuel gas streams produced...

  15. 40 CFR 60.107a - Monitoring of emissions and operations for fuel gas combustion devices.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... this section will be considered inherently low in sulfur content. (i) Pilot gas for heaters and flares... produced in process units that are intolerant to sulfur contamination, such as fuel gas streams produced...

  16. Effect of air sparging on fate and transport of trichloroethylene in chambers with alfalfa plants

    SciTech Connect

    Zhang, Q.; Hu, J.; Erickson, L.E.; Davis, L.C.

    1997-12-31

    To study the effect of air sparging in soil with trichloroethylene present as a dense nonaqueous phase, air was supplied through pipes installed at the bottom of two chambers planted with alfalfa. Air input rate was 2.14 L/m{sup 2}/day. The fate of trichloroethylene (TCE) was investigated by monitoring TCE concentration in both outflow groundwater and soil gas. Comparison of these results with those of the previous study without air sparging indicates that air sparging appreciably increases the groundwater concentration of TCE. The soil gas at the surface shows even greater concentration difference. The flux of TCE to the atmosphere is increased significantly by air input. Accordingly, the authors can conclude that air sparging improved mass transfer of TCE from the nonaqueous phase to groundwater phase. Air sparging appeared to negatively impact the health of the alfalfa because of the elevated TCE present in the vadose zone of the chamber.

  17. A New Screening Method for Methane in Soil Gas Using Existing Groundwater Monitoring Wells

    EPA Science Inventory

    Methane in soil gas may have undesirable consequences. The soil gas may be able to form a flammable mixture with air and present an explosion hazard. Aerobic biodegradation of the methane in soil gas may consume oxygen that would otherwise be available for biodegradation of gasol...

  18. 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

    ... Method Request Submission Deadline for Petroleum and Natural Gas Systems Source Category AGENCY... deadline by which owners or operators of facilities subject to the petroleum and natural gas systems source... facilities subject to the petroleum and natural gas systems source category, subpart W, of the Greenhouse...

  19. 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

    ... Method Request Submission Deadline for Petroleum and Natural Gas Systems Source Category AGENCY... owners or operators of facilities subject to the petroleum and natural gas systems source category of the...''). This final rule affects owners or operators of petroleum and natural gas systems. Regulated...

  20. Characterization of a Small Form Factor Multipole RGA for Process Chamber Monitoring and for Reduction in Time to Complete Routine Preventive Maintenance

    SciTech Connect

    Johnson, Ron; Winningham, Brannon; Schuur, John

    2008-11-03

    A small form-factor, multipole Residual Gas Analyzer (RGA) has been used to study steady state and post-PM conditions in an Axcelis GSD ion implanter. The RGA properties and specifications are discussed and data is presented to illustrate N{sub 2}, O{sub 2}, and H{sub 2}O pump-down curve characteristics. Baseline performance is compared to performance following invasive activities to determine applicability for eliminating explicit He leak checking requirements and for the determination of how quickly a machine may be returned to production. The target ion implanter was an Axcelis GSD/200E.

  1. Instrumented Pressure Testing Chamber (IPTC) Characterization of Methane Gas Hydrate-Bearing Pressure Cores Collected from the Methane Production Test Site in the Eastern Nankai Trough, Offshore Japan

    NASA Astrophysics Data System (ADS)

    Waite, W. F.; Santamarina, J. C.; Dai, S.; Winters, W. J.; Yoneda, J.; Konno, Y.; Nagao, J.; Suzuki, K.; Fujii, T.; Mason, D. H.; Bergeron, E.

    2014-12-01

    Pressure cores obtained at the Daini-Atsumi Knoll in the eastern Nankai Trough, the site of the methane hydrate production test completed by the Methane Hydrate Resources in Japan (MH21) project in March 2013, were recovered from ~300 meters beneath the sea floor at close to in situ pressure. Cores were subsequently stored at ~20 MPa and ~5°C, which maintained hydrate in the cores within stability conditions. Pressure core physical properties were measured at 10 MPa and ~6°C, also within the methane hydrate stability field, using the IPTC and other Pressure Core Characterization Tools (PCCTs). Discrete IPTC measurements were carried out in strata ranging from silty sands to clayey silts within the turbidite sequences recovered in the cores. As expected, hydrate saturations were greatest in more permeable coarser-grained layers. Key results include: 1) Where hydrate saturation exceeded 40% in sandy sediments, the gas hydrate binds sediment grains within the matrix. The pressure core analyses yielded nearly in situ mechanical properties despite the absence of effective stress in the IPTC. 2) In adjacent fine-grained sediment (hydrate saturation < 15%), hydrate did not significantly bind the sediment. IPTC results in these locations were consistent with the zero effective-stress limit of comparable measurements made in PCCT devices that are designed to restore the specimen's in situ effective stress. In sand-rich intervals with high gas hydrate saturations, the measured compressional and shear wave velocities suggest that hydrate acts as a homogeneously-distributed, load-bearing member of the bulk sediment. The sands with high gas hydrate saturations were prone to fracturing (brittle failure) during insertion of the cone penetrometer and electrical conductivity probes. Authors would like to express their sincere appreciation to MH21 and the Ministry of Economy, Trade and Industry for permitting this work to be disclosed at the 2014 Fall AGU meeting.

  2. Sealed Plant-Growth Chamber For Clinostat

    NASA Technical Reports Server (NTRS)

    Brown, Christopher S.; Dreschel, Thomas W.

    1993-01-01

    Laboratory chamber for growing plants used to measure photosynthesis and respiration in simulated microgravity. Holds plant specimens while rotated on clinostat, see article, "Clinostat Delivers Power To Plant-Growth Cabinets" (KSC-11537). Provides way of comparing gas-exchange rates of plants rotated horizontally on clinostat with those of stationary or vertically rotated plants. Gas extracted for analysis without stopping clinostat. Chamber includes potlike base and cylindrical cover, both made of transparent acrylic pipe. Gasket forms seal between cover and bottom plate of base. Cover bolted to pot baseplate, which in turn bolted to clinostat.

  3. Outgassing measurement of the aluminum alloy UHV chamber

    NASA Technical Reports Server (NTRS)

    Miyamoto, M.; Itoh, T.; Komaki, S.; Narushima, K.; Ishimaru, H.

    1986-01-01

    A large vacuum chamber (580 mm diameter) was fabricated from an aluminum alloy surface treated by a special process normally used on small chambers. The chamber was tested unbaked and baked at various temperatures, pressures, and holding periods. The chamber was filled with N2 gas, and the outgassing rate was measured after one hour. Then the ultimate pressure was measured. Outgassing rates for baked and unbaked groups were compared. It is concluded that the same surface treatment technique can be used on both large and small chambers produced by the same special extrusion process.

  4. Monitoring of air pollution in the atmosphere around Oman Liquid Natural Gas (OLNG) plant.

    PubMed

    Abdul-Wahab, Sabah A

    2005-01-01

    This study was basically designed to assess the potential environmental air quality impacts arising from the existing two operational trains at the Oman Liquid Natural Gas (OLNG) plant. The results of the paper contain a baseline survey of the existing environment. The pollutants studied included methane (CH4), non-methane hydrocarbons (NMHC), carbon monoxide (CO), nitrogen oxides (NOx), and suspended particulate matters (dust PM 10). Meteorological parameters monitored simultaneously include wind speed and direction, air temperature, and relative humidity. The air quality data were used to determine the diurnal and monthly variations in the pollutants. Description levels of the pollutants with respect to meteorological data were also used in analysis. Moreover, a statistical analysis of the collected data was presented. Generally, the results indicated that the mean concentrations of pollutants were low to cause any significant impact in air quality. The area had no problem in meeting the air quality standards for CO and NO2. It was also found that there was a random relationship between CO and NMHC, and between NO and NOx (no apparent correlation). The diurnal peaks of NOx, NO2, THC, and NMHC over a 24-h period were observed at around 9:00-10:00 AM (morning peak). For NO, NO2, and NOx, another peak was seen at around 5:00 PM (evening peak). Furthermore, the measured concentrations for NO2, NOx, and CO were found higher in winter than in summer. The study would help to gain a better understanding of local background levels of air pollutants at the area prior to the construction of new industrial projects, and to prepare action plans for controlling pollution in the area.

  5. Performance of a transpiration-regenerative cooled rocket thrust chamber

    NASA Technical Reports Server (NTRS)

    Valler, H. W.

    1979-01-01

    The analysis, design, fabrication, and testing of a liquid rocket engine thrust chamber which is gas transpiration cooled in the high heat flux convergent portion of the chamber and water jacket cooled (simulated regenerative) in the barrel and divergent sections of the chamber are described. The engine burns LOX-hydrogen propellants at a chamber pressure of 600 psia. Various transpiration coolant flow rates were tested with resultant local hot gas wall temperatures in the 800 F to 1400 F range. The feasibility of transpiration cooling with hydrogen and helium, and the use of photo-etched copper platelets for heat transfer and coolant metering was successfully demonstrated.

  6. Gas chromatography/matrix-isolation apparatus

    DOEpatents

    Reedy, Gerald T.

    1986-01-01

    A gas-sample collection device provides matrix isolation of individual gas bands from a gas chromatographic separation and for the spectroscopic analysis of the individual sample bands. The device includes a vacuum chamber containing a rotatably supported, specular carousel having at least one reflecting surface for holding a sample deposited thereon. A gas inlet is provided for depositing a mixture of sample and matrix material on the reflecting surface which is maintained at a sufficiently low temperature to cause solidification. A first parabolic mirror directs an incident beam of electromagnetic radiation, such as in the infrared (IR) spectrum, from a source onto the sample/matrix mixture while a second parabolic mirror directs a second beam of electromagnetic radiation reflected by the specular surface to an IR spectrometer for determining the absorption spectra of the sample material deposited on the reflecting surface. The pair of off-axis parabolic mirrors having a common focal point are positioned outside of the vacuum chamber and may be displaced in combination for improved beam positioning and alignment. The carousel is provided with an aperture for each reflecting surface to facilitate accurate positioning of the incident beam relative to the gas-samples under analysis. Improved gas-sample deposition is insured by the use of a long focal length stereomicroscope positioned outside of the vacuum chamber for monitoring sample formation through a window, while the sample collector is positioned outside of the zone bounded by the incident and reflected electromagnetic beams for improved sample access and monitoring.

  7. Multi-Method Monitoring of Shallow Gas Injection in Saline Coastal Reservoir at Maguelone (Languedoc coastline, France)

    NASA Astrophysics Data System (ADS)

    Denchik, N.; Pezard, P. A.; Lofi, J.; Luquot, L.; Neyens, D.; Jaafar, O.; Perroud, H.; Abdelghafour, H.; Henry, G.; Levannier, A.

    2014-12-01

    Geological storage of CO2 is still a recent technology and many questions remain open, particularly for saline formations. Geological storage in accessible saline formations is, in fact, expected to become over time more important than that in depleted hydrocarbon reservoirs. The Maguelone shallow experimental site, located near Montpellier (Languedoc, France) has been used over the past few years to perform CO2 injection experiments. The geology, petrophysics and hydrology of this site are well known from previous studies. The presence of small saline coastal reservoirs bounded above and below by clay-rich layers provides an opportunity to study a saline formation for geological storage at field laboratory scale with a set of hydrogeophysical (seismic, electrical, sonic, pressure) and geochemical (pH, minor and major ion concentrations) methods, either downhole or at surface. Series of experiments can be run at moderate costs from the shallow depth of one of these reservoirs (13-16 m), offering flexibility for testing different monitoring configurations, performing repeated injection releases with variable injection parameters and type of gas (e.g., N2, CO2), and cross-calibrating the monitoring methods. Moreover, additional methods/boreholes can be easily implemented at this experimental site. Three N2 injections were thus undertaken at Maguelone in 2012 to measure the site response to neutral gas injection. An experiment involving the release of CO2 was successively conducted in January 2013. A volume of 111 m3 of CO2 was injected during 3.5 hours. Both the N2 and CO2 gas plumes were detected by all monitoring techniques, and the response to gas propagation was instantaneous. Integrating the lesson learned from past injection experiments, the next stage of the project will allow to establish the best guidelines for CO2 injection and post-injection monitoring and, in perspective, not only to detect the CO2 plume but to quantify CO2 migration in the subsurface.

  8. Single chamber fuel cells: Flow geometry, rate and composition considerations

    SciTech Connect

    Stefan, Ionel C.; Jacobson, Craig P.; Visco, Steven J.; De Jonghe, Lutgard C.

    2003-11-17

    Four different single chamber fuel cell designs were compared using propane-air gas mixtures. Gas flow around the electrodes has a significant influence on the open circuit voltage and the power density of the cell. The strong influence of flow geometry is likely due to its effect on gas composition, particularly on the oxygen chemical potential at the two electrodes as a result of gas mixing. The chamber design which exposes the cathode first to the inlet gas was found to yield the best performance at lower flow rates, while the open tube design with the electrodes equally exposed to the inlet gas worked best at higher flow rates.

  9. A greenhouse-gas information system monitoring and validating emissions reporting and mitigation

    SciTech Connect

    Jonietz, Karl K; Dimotakis, Paul E; Walker, Bruce C

    2011-09-26

    Current GHG-mitigating regimes, whether internationally agreed or self-imposed, rely on the aggregation of self-reported data, with limited checks for consistency and accuracy, for monitoring. As nations commit to more stringent GHG emissions-mitigation actions and as economic rewards or penalties are attached to emission levels, self-reported data will require independent confirmation that they are accurate and reliable, if they are to provide the basis for critical choices and actions that may be required. Supporting emissions-mitigation efforts and agreements, as well as monitoring energy- and fossil-fuel intensive national and global activities would be best achieved by a process of: (1) monitoring of emissions and emission-mitigation actions, based, in part, on, (2) (self-) reporting of pertinent bottom-up inventory data, (3) verification that reported data derive from and are consistent with agreed-upon processes and procedures, and (4) validation that reported emissions and emissions-mitigation action data are correct, based on independent measurements (top-down) derived from a suite of sensors in space, air, land, and, possibly, sea, used to deduce and attribute anthropogenic emissions. These data would be assessed and used to deduce and attribute measured GHG concentrations to anthropogenic emissions, attributed geographically and, to the extent possible, by economic sector. The validation element is needed to provide independent assurance that emissions are in accord with reported values, and should be considered as an important addition to the accepted MRV process, leading to a MRV&V process. This study and report focus on attributes of a greenhouse-gas information system (GHGIS) needed to support MRV&V needs. These needs set the function of such a system apart from scientific/research monitoring of GHGs and carbon-cycle systems, and include (not exclusively): the need for a GHGIS that is operational, as required for decision-support; the need for a

  10. Utilization of soil gas monitoring to determine feasibility and effectiveness of in situ bioventing in hydrocarbon-contaminated soils

    SciTech Connect

    Frishmuth, R.A.; Ratz, J.W.; Hall, J.F.

    1996-12-31

    To determine the feasibility and effectiveness of in situ bioventing, careful monitoring of soil gas chemistry is essential. Prior to design of a bioventing system, initial soil gas surveys should be performed. Concentrations of three constituents, oxygen (O{sub 2}), carbon dioxide (CO{sub 2}), and total volatile hydrocarbons (TVH), are used in bioventing design. TVH are an indicator of contaminant distribution; O{sub 2} and CO{sub 2} are indicators of biodegradation activity. Analysis of soil gas data collected during pilot-scale testing is the primary design basis for full-scale remediation systems. Biodegradation rates determined from respiration tests are used to estimate the length of time that a system will have to operate to remediate the contamination. Air permeability of the soil, calculated from permeability testing, determines the number and spacing of air injection wells that will be required to ensure adequate oxygen influence through the entire contaminated area.

  11. Determination of testosterone in plasma from men by gas chromatography/mass spectrometry, with high-resolution selected-ion monitoring and metastable peak monitoring

    SciTech Connect

    Finlay, E.M.; Gaskell, S.J.

    1981-07-01

    Highly specific methods are described for determining testosterone in plasma or serum from men. Extract fractions obtained by selective isolation procedures are converted to tert-butyldimethylsilyl (TBDMS) oximes/TBDMS ethers or methyl oximes/TBDMS ethers and analyzed by gas chromatography/mass spectrometry in the high-resolution selected-ion monitoring or metastable peak-monitoring modes. (2H3)Testosterone and unlabeled 17-epitestosterone are used as the respective internal standards. When we applied the two procedures to analysis of samples of pooled plasma and serum used for external quality assessment of routine assays, the results agreed well. Interlaboratory values for mean concentrations obtained by routine immunoassays (y) consistently exceeded values obtained by our technique (x), although the values closely correlated (r . 0.997; y . 1.008x + 0.564 nmol/L).

  12. Wide range radioactive gas concentration detector

    DOEpatents

    Anderson, David F.

    1984-01-01

    A wide range radioactive gas concentration detector and monitor which is capable of measuring radioactive gas concentrations over a range of eight orders of magnitude. The device of the present invention is designed to have an ionization chamber which is sufficiently small to give a fast response time for measuring radioactive gases but sufficiently large to provide accurate readings at low concentration levels. Closely spaced parallel plate grids provide a uniform electric field in the active region to improve the accuracy of measurements and reduce ion migration time so as to virtually eliminate errors due to ion recombination. The parallel plate grids are fabricated with a minimal surface area to reduce the effects of contamination resulting from absorption of contaminating materials on the surface of the grids. Additionally, the ionization chamber wall is spaced a sufficient distance from the active region of the ionization chamber to minimize contamination effects.

  13. Turmoil at Turrialba Volcano (Costa Rica): Degassing and eruptive processes inferred from high-frequency gas monitoring

    NASA Astrophysics Data System (ADS)

    Moor, J. Maarten; Aiuppa, A.; Avard, G.; Wehrmann, H.; Dunbar, N.; Muller, C.; Tamburello, G.; Giudice, G.; Liuzzo, M.; Moretti, R.; Conde, V.; Galle, B.

    2016-08-01

    Eruptive activity at Turrialba Volcano (Costa Rica) has escalated significantly since 2014, causing airport and school closures in the capital city of San José. Whether or not new magma is involved in the current unrest seems probable but remains a matter of debate as ash deposits are dominated by hydrothermal material. Here we use high-frequency gas monitoring to track the behavior of the volcano between 2014 and 2015 and to decipher magmatic versus hydrothermal contributions to the eruptions. Pulses of deeply derived CO2-rich gas (CO2/Stotal > 4.5) precede explosive activity, providing a clear precursor to eruptive periods that occurs up to 2 weeks before eruptions, which are accompanied by shallowly derived sulfur-rich magmatic gas emissions. Degassing modeling suggests that the deep magmatic reservoir is ~8-10 km deep, whereas the shallow magmatic gas source is at ~3-5 km. Two cycles of degassing and eruption are observed, each attributed to pulses of magma ascending through the deep reservoir to shallow crustal levels. The magmatic degassing signals were overprinted by a fluid contribution from the shallow hydrothermal system, modifying the gas compositions, contributing volatiles to the emissions, and reflecting complex processes of scrubbing, displacement, and volatilization. H2S/SO2 varies over 2 orders of magnitude through the monitoring period and demonstrates that the first eruptive episode involved hydrothermal gases, whereas the second did not. Massive degassing (>3000 T/d SO2 and H2S/SO2 > 1) followed, suggesting boiling off of the hydrothermal system. The gas emissions show a remarkable shift to purely magmatic composition (H2S/SO2 < 0.05) during the second eruptive period, reflecting the depletion of the hydrothermal system or the establishment of high-temperature conduits bypassing remnant hydrothermal reservoirs, and the transition from phreatic to phreatomagmatic eruptive activity.

  14. Turmoil at Turrialba Volcano (Costa Rica): Degassing and eruptive processes inferred from high-frequency gas monitoring.

    PubMed

    de Moor, J Maarten; Aiuppa, A; Avard, G; Wehrmann, H; Dunbar, N; Muller, C; Tamburello, G; Giudice, G; Liuzzo, M; Moretti, R; Conde, V; Galle, B

    2016-08-01

    Eruptive activity at Turrialba Volcano (Costa Rica) has escalated significantly since 2014, causing airport and school closures in the capital city of San José. Whether or not new magma is involved in the current unrest seems probable but remains a matter of debate as ash deposits are dominated by hydrothermal material. Here we use high-frequency gas monitoring to track the behavior of the volcano between 2014 and 2015 and to decipher magmatic versus hydrothermal contributions to the eruptions. Pulses of deeply derived CO2-rich gas (CO2/Stotal > 4.5) precede explosive activity, providing a clear precursor to eruptive periods that occurs up to 2 weeks before eruptions, which are accompanied by shallowly derived sulfur-rich magmatic gas emissions. Degassing modeling suggests that the deep magmatic reservoir is ~8-10 km deep, whereas the shallow magmatic gas source is at ~3-5 km. Two cycles of degassing and eruption are observed, each attributed to pulses of magma ascending through the deep reservoir to shallow crustal levels. The magmatic degassing signals were overprinted by a fluid contribution from the shallow hydrothermal system, modifying the gas compositions, contributing volatiles to the emissions, and reflecting complex processes of scrubbing, displacement, and volatilization. H2S/SO2 varies over 2 orders of magnitude through the monitoring period and demonstrates that the first eruptive episode involved hydrothermal gases, whereas the second did not. Massive degassing (>3000 T/d SO2 and H2S/SO2 > 1) followed, suggesting boiling off of the hydrothermal system. The gas emissions show a remarkable shift to purely magmatic composition (H2S/SO2 < 0.05) during the second eruptive period, reflecting the depletion of the hydrothermal system or the establishment of high-temperature conduits bypassing remnant hydrothermal reservoirs, and the transition from phreatic to phreatomagmatic eruptive activity.

  15. Liquid rocket engine self-cooled combustion chambers

    NASA Technical Reports Server (NTRS)

    1977-01-01

    Self-cooled combustion chambers are chambers in which the chamber wall temperature is controlled by methods other than fluid flow within the chamber wall supplied from an external source. In such chambers, adiabatic wall temperature may be controlled by use of upstream fluid components such as the injector or a film-coolant ring, or by internal flow of self-contained materials; e.g. pyrolysis gas flow in charring ablators, and the flow of infiltrated liquid metals in porous matrices. Five types of self-cooled chambers are considered in this monograph. The name identifying the chamber is indicative of the method (mechanism) by which the chamber is cooled, as follows: ablative; radiation cooled; internally regenerative (Interegen); heat sink; adiabatic wall. Except for the Interegen and heat sink concepts, each chamber type is discussed separately. A separate and final section of the monograph deals with heat transfer to the chamber wall and treats Stanton number evaluation, film cooling, and film-coolant injection techniques, since these subjects are common to all chamber types. Techniques for analysis of gas film cooling and liquid film cooling are presented.

  16. The Mobile Chamber

    NASA Technical Reports Server (NTRS)

    Scharfstein, Gregory; Cox, Russell

    2012-01-01

    A document discusses a simulation chamber that represents a shift from the thermal-vacuum chamber stereotype. This innovation, currently in development, combines the capabilities of space simulation chambers, the user-friendliness of modern-day electronics, and the modularity of plug-and-play computing. The Mobile Chamber is a customized test chamber that can be deployed with great ease, and is capable of bringing payloads at temperatures down to 20 K, in high vacuum, and with the desired metrology instruments integrated to the systems control. Flexure plans to lease Mobile Chambers, making them affordable for smaller budgets and available to a larger customer base. A key feature of this design will be an Apple iPad-like user interface that allows someone with minimal training to control the environment inside the chamber, and to simulate the required extreme environments. The feedback of thermal, pressure, and other measurements is delivered in a 3D CAD model of the chamber's payload and support hardware. This GUI will provide the user with a better understanding of the payload than any existing thermal-vacuum system.

  17. High resolution drift chambers

    SciTech Connect

    Va'vra, J.

    1985-07-01

    High precision drift chambers capable of achieving less than or equal to 50 ..mu..m resolutions are discussed. In particular, we compare so called cool and hot gases, various charge collection geometries, several timing techniques and we also discuss some systematic problems. We also present what we would consider an ''ultimate'' design of the vertex chamber. 50 refs., 36 figs., 6 tabs.

  18. Target chambers for gammashpere

    SciTech Connect

    Carpenter, M.P.; Falout, J.W.; Nardi, B.G.

    1995-08-01

    One of our responsibilities for Gammasphere, was designing and constructing two target chambers and associated beamlines to be used with the spectrometer. The first chamber was used with the early implementation phase of Gammasphere, and consisted of two spun-Al hemispheres welded together giving a wall thickness of 0.063 inches and a diameter of 12 inches.

  19. A soundproof pressure chamber.

    PubMed

    Kitahara, M; Kodama, A; Ozawa, H; Inoue, S

    1994-01-01

    For neurotological research we designed a soundproof pressure chamber in which pressure can be adjusted +/- 1000 mmH2O at the rate of less than 100 mmH2O per second. Noise in the chamber can be maintained under 30-35 dB while pressure is kept at a given level.

  20. Static diffusion cloud chambers

    NASA Technical Reports Server (NTRS)

    Ayers, G.

    1981-01-01

    The chamber geometry and optical arrangement are described. The supersaturation range is given and consists of readings taken at five fi