WorldWideScience

Sample records for situ gas temperature

  1. In situ gas temperature measurements by UV-absorption spectroscopy

    DEFF Research Database (Denmark)

    Fateev, Alexander; Clausen, Sønnik

    2009-01-01

    The absorption spectrum of the NO A(2)Sigma(+) uniform and stable gas temperatures over a 0.533 m path....... The accuracy of both methods is discussed. Validation of the classical Lambert-Beer law has been demonstrated at NO concentrations up to 500 ppm and gas temperatures up to 1,500 degrees C over an optical absorption path length of 0.533 m....

  2. In Situ Apparatus to Study Gas-Metal Reactions and Wettability at High Temperatures for Hot-Dip Galvanizing Applications

    Science.gov (United States)

    Koltsov, A.; Cornu, M.-J.; Scheid, J.

    2018-02-01

    The understanding of gas-metal reactions and related surface wettability at high temperatures is often limited due to the lack of in situ surface characterization. Ex situ transfers at low temperature between annealing furnace, wettability device, and analytical tools induce noticeable changes of surface composition distinct from the reality of the phenomena.Therefore, a high temperature wettability device was designed in order to allow in situ sample surface characterization by x-rays photoelectron spectroscopy after gas/metal and liquid metal/solid metal surface reactions. Such airless characterization rules out any contamination and oxidation of surfaces and reveals their real composition after heat treatment and chemical reaction. The device consists of two connected reactors, respectively, dedicated to annealing treatments and wettability measurements. Heat treatments are performed in an infrared lamp furnace in a well-controlled atmosphere conditions designed to reproduce gas-metal reactions occurring during the industrial recrystallization annealing of steels. Wetting experiments are carried out in dispensed drop configuration with the precise control of the deposited droplets kinetic energies. The spreading of drops is followed by a high-speed CCD video camera at 500-2000 frames/s in order to reach information at very low contact time. First trials have started to simulate phenomena occurring during recrystallization annealing and hot-dip galvanizing on polished pure Fe and FeAl8 wt.% samples. The results demonstrate real surface chemistry of steel samples after annealing when they are put in contact with liquid zinc alloy bath during hot-dip galvanizing. The wetting results are compared to literature data and coupled with the characterization of interfacial layers by FEG-Auger. It is fair to conclude that the results show the real interest of such in situ experimental setup for interfacial chemistry studies.

  3. Novel Modified Optical Fibers for High Temperature In-Situ Miniaturized Gas Sensors in Advanced Fossil Energy Systems

    Energy Technology Data Exchange (ETDEWEB)

    Pickrell, Gary [Virginia Polytechnic Institute & State University, Blacksburg, VA (United States); Scott, Brian [Virginia Polytechnic Institute & State University, Blacksburg, VA (United States)

    2014-06-30

    This report covers the technical progress on the program “Novel Modified Optical Fibers for High Temperature In-Situ Miniaturized Gas Sensors in Advanced Fossil Energy Systems”, funded by the National Energy Technology Laboratory of the U.S. Department of Energy, and performed by the Materials Science & Engineering and Electrical & Computer Engineering Departments at Virginia Tech, and summarizes technical progress from July 1st, 2005 –June 30th, 2014. The objective of this program was to develop novel fiber materials for high temperature gas sensors based on evanescent wave absorption in optical fibers. This project focused on two primary areas: the study of a sapphire photonic crystal fiber (SPCF) for operation at high temperature and long wavelengths, and a porous glass based fiber optic sensor for gas detection. The sapphire component of the project focused on the development of a sapphire photonic crystal fiber, modeling of the new structures, fabrication of the optimal structure, development of a long wavelength interrogation system, testing of the optical properties, and gas and temperature testing of the final sensor. The fabrication of the 6 rod SPCF gap bundle (diameter of 70μm) with a hollow core was successfully constructed with lead-in and lead-out 50μm diameter fiber along with transmission and gas detection testing. Testing of the sapphire photonic crystal fiber sensor capabilities with the developed long wavelength optical system showed the ability to detect CO2 at or below 1000ppm at temperatures up to 1000°C. Work on the porous glass sensor focused on the development of a porous clad solid core optical fiber, a hollow core waveguide, gas detection capabilities at room and high temperature, simultaneous gas species detection, suitable joining technologies for the lead-in and lead-out fibers and the porous sensor, sensor system sensitivity improvement, signal processing improvement, relationship between pore structure and fiber

  4. Phenomenological in-situ TEM gas exposure studies of palladium particles on MgO at room temperature

    Science.gov (United States)

    Heinemann, K.; Poppa, H.; Osaka, T.

    1983-01-01

    It has been found that very small vapor-deposited catalytically active metal particles in the 1-2 nm size range on metal oxide substrates can undergo significant changes when they are exposed to gases such as oxygen or air, or even when allowed to 'anneal' at room temperature (RT) under vacuum conditions. The present investigation is concerned with continued in-situ gas exposures of as-deposited, 1 to 2 nm size palladium particles on MgO to air, oxygen, nitrogen, hydrogen, CO, and water vapor at RT. It is found that the low-pressure exposure to various gases at RT can significantly affect small palladium particles supported on MgO surfaces. Exposure to oxygen for 3 min at 0.0002 m bar produces a considerable amount of coalescence, flattening of the particles, and some distinct crystallographic particle shapes.

  5. In-situ study of the gas-phase composition and temperature of an intermediate-temperature solid oxide fuel cell anode surface fed by reformate natural gas

    Science.gov (United States)

    Santoni, F.; Silva Mosqueda, D. M.; Pumiglia, D.; Viceconti, E.; Conti, B.; Boigues Muñoz, C.; Bosio, B.; Ulgiati, S.; McPhail, S. J.

    2017-12-01

    An innovative experimental setup is used for in-depth and in-operando characterization of solid oxide fuel cell anodic processes. This work focuses on the heterogeneous reactions taking place on a 121 cm2 anode-supported cell (ASC) running with a H2, CH4, CO2, CO and steam gas mixture as a fuel, using an operating temperature of 923 K. The results have been obtained by analyzing the gas composition and temperature profiles along the anode surface in different conditions: open circuit voltage (OCV) and under two different current densities, 165 mA cm-2 and 330 mA cm-2, corresponding to 27% and 54% of fuel utilization, respectively. The gas composition and temperature analysis results are consistent, allowing to monitor the evolution of the principal chemical and electrochemical reactions along the anode surface. A possible competition between CO2 and H2O in methane internal reforming is shown under OCV condition and low current density values, leading to two different types of methane reforming: Steam Reforming and Dry Reforming. Under a current load of 40 A, the dominance of exothermic reactions leads to a more marked increase of temperature in the portion of the cell close to the inlet revealing that current density is not uniform along the anode surface.

  6. In Situ UV-Visible Assessment of Iron-Based High-Temperature Water-Gas Shift Catalysts Promoted with Lanthana: An Extent of Reduction Study

    Directory of Open Access Journals (Sweden)

    Basseem B. Hallac

    2018-02-01

    Full Text Available The extent of reduction of unsupported iron-based high-temperature water-gas shift catalysts with small (<5 wt % lanthana contents was studied using UV-visible spectroscopy. Temperature- programmed reduction measurements showed that lanthana content higher than 0.5 wt % increased the extent of reduction to metallic Fe, while 0.5 wt % of lanthana facilitated the reduction to Fe3O4. In situ measurements on the iron oxide catalysts using mass and UV-visible spectroscopies permitted the quantification of the extent of reduction under temperature-programmed reduction and high-temperature water-gas shift conditions. The oxidation states were successfully calibrated against normalized absorbance spectra of visible light using the Kubelka-Munk theory. The normalized absorbance relative to the fully oxidized Fe2O3 increased as the extent of reduction increased. XANES suggested that the average bulk iron oxidation state during the water-gas shift reaction was Fe+2.57 for the catalyst with no lanthana and Fe+2.54 for the catalysts with 1 wt % lanthana. However, the UV-vis spectra suggest that the surface oxidation state of iron would be Fe+2.31 for the catalyst with 1 wt % lanthana if the oxidation state of iron in the catalyst with 0 wt % lanthana were Fe+2.57. The findings of this paper emphasize the importance of surface sensitive UV-visible spectroscopy for determining the extent of catalyst reduction during operation. The paper highlights the potential to use bench-scale UV-visible spectroscopy to study the surface chemistry of catalysts instead of less-available synchrotron X-ray radiation facilities.

  7. EQUILGAS: Program to estimate temperatures and in situ two-phase conditions in geothermal reservoirs using three combined FT-HSH gas equilibria models

    Science.gov (United States)

    Barragán, Rosa María; Núñez, José; Arellano, Víctor Manuel; Nieva, David

    2016-03-01

    Exploration and exploitation of geothermal resources require the estimation of important physical characteristics of reservoirs including temperatures, pressures and in situ two-phase conditions, in order to evaluate possible uses and/or investigate changes due to exploitation. As at relatively high temperatures (>150 °C) reservoir fluids usually attain chemical equilibrium in contact with hot rocks, different models based on the chemistry of fluids have been developed that allow deep conditions to be estimated. Currently either in water-dominated or steam-dominated reservoirs the chemistry of steam has been useful for working out reservoir conditions. In this context, three methods based on the Fischer-Tropsch (FT) and combined H2S-H2 (HSH) mineral-gas reactions have been developed for estimating temperatures and the quality of the in situ two-phase mixture prevailing in the reservoir. For these methods the mineral buffers considered to be controlling H2S-H2 composition of fluids are as follows. The pyrite-magnetite buffer (FT-HSH1); the pyrite-hematite buffer (FT-HSH2) and the pyrite-pyrrhotite buffer (FT-HSH3). Currently from such models the estimations of both, temperature and steam fraction in the two-phase fluid are obtained graphically by using a blank diagram with a background theoretical solution as reference. Thus large errors are involved since the isotherms are highly nonlinear functions while reservoir steam fractions are taken from a logarithmic scale. In order to facilitate the use of the three FT-HSH methods and minimize visual interpolation errors, the EQUILGAS program that numerically solves the equations of the FT-HSH methods was developed. In this work the FT-HSH methods and the EQUILGAS program are described. Illustrative examples for Mexican fields are also given in order to help the users in deciding which method could be more suitable for every specific data set.

  8. In situ TEM observation of solid-gas reactions

    International Nuclear Information System (INIS)

    Kishita, K; Kamino, T; Watabe, A; Kuroda, K; Saka, H

    2008-01-01

    Under a gaseous atmosphere at high temperatures, almost all the materials (metal, catalysts, etc.) change their structures and properties. For the research and development of materials, it is of vital importance to clarify mechanisms of solid-gas and liquid-gas reactions. Recently an in situ TEM system combined with an environmental holder, which has a gas injection nozzle close to a specimen-heating element, has been developed. The gas injection nozzle permits gas to flow around the specimens sitting on the heating element made of a fine W filament. The newly developed in situ TEM has a differential pumping system; therefore, the pressure in the specimen chamber is maintained in the range of higher than 1 Pa, while the pressure in the electron gun chamber can be kept in the range of 10 -5 Pa. This system was applied to in situ observation of chemical reactions of metals with gases: Observation of oxidation and reduction under a gas pressure ranging from 10 -5 Pa to 1 Pa at high temperatures (room temperature to ∼1473 K) were successfully carried out on pure metal and rare metal catalysts at near-atomic resolution. This in situ environmental TEM system is promising for clarifying mechanisms of many solid-gas and liquid-gas reactions that take place at high temperatures under a gas atmosphere.

  9. In situ high-temperature gas sensors: continuous monitoring of the combustion quality of different wood combustion systems and optimization of combustion process

    Directory of Open Access Journals (Sweden)

    H. Kohler

    2018-03-01

    Full Text Available The sensing characteristics and long-term stability of different kinds of CO ∕ HC gas sensors (non-Nernstian mixed potential type during in situ operation in flue gas from different types of low-power combustion systems (wood-log- and wood-chip-fuelled were investigated. The sensors showed representative but individual sensing behaviour with respect to characteristically varying flue gas composition over the combustion process. The long-term sensor signal stability evaluated by repeated exposure to CO ∕ H2 ∕ N2 ∕ synthetic air mixtures showed no sensitivity loss after operation in the flue gas. Particularly for one of the sensors (Heraeus GmbH, this high signal stability was observed in a field test experiment even during continuous operation in the flue gas of the wood-chip firing system over 4 months. Furthermore, it was experimentally shown that the signals of these CO ∕ HC sensing elements yield important additional information about the wood combustion process. This was demonstrated by the adaptation of an advanced combustion airstream control algorithm on a wood-log-fed fireplace and by the development of a combustion quality monitoring system for wood-chip-fed central heaters.

  10. An in situ spatially resolved analytical technique to simultaneously probe gas phase reactions and temperature within the packed bed of a plug flow reactor.

    Science.gov (United States)

    Touitou, Jamal; Burch, Robbie; Hardacre, Christopher; McManus, Colin; Morgan, Kevin; Sá, Jacinto; Goguet, Alexandre

    2013-05-21

    This paper reports the detailed description and validation of a fully automated, computer controlled analytical method to spatially probe the gas composition and thermal characteristics in packed bed systems. As an exemplar, we have examined a heterogeneously catalysed gas phase reaction within the bed of a powdered oxide supported metal catalyst. The design of the gas sampling and the temperature recording systems are disclosed. A stationary capillary with holes drilled in its wall and a moveable reactor coupled with a mass spectrometer are used to enable sampling and analysis. This method has been designed to limit the invasiveness of the probe on the reactor by using the smallest combination of thermocouple and capillary which can be employed practically. An 80 μm (O.D.) thermocouple has been inserted in a 250 μm (O.D.) capillary. The thermocouple is aligned with the sampling holes to enable both the gas composition and temperature profiles to be simultaneously measured at equivalent spatially resolved positions. This analysis technique has been validated by studying CO oxidation over a 1% Pt/Al2O3 catalyst and the spatial resolution profiles of chemical species concentrations and temperature as a function of the axial position within the catalyst bed are reported.

  11. Temperature and the Ideal Gas

    Science.gov (United States)

    Daisley, R. E.

    1973-01-01

    Presents some organized ideas in thermodynamics which are suitable for use with high school (GCE A level or ONC) students. Emphases are placed upon macroscopic observations and intimate connection of the modern definition of temperature with the concept of ideal gas. (CC)

  12. In situ bioremediation of chlorinated solvent with natural gas

    International Nuclear Information System (INIS)

    Rabold, D.E.

    1996-01-01

    A bioremediation system for the removal of chlorinated solvents from ground water and sediments is described. The system involves the the in-situ injection of natural gas (as a microbial nutrient) through an innovative configuration of horizontal wells

  13. Treatment of gas from an in situ conversion process

    Science.gov (United States)

    Diaz, Zaida [Katy, TX; Del Paggio, Alan Anthony [Spring, TX; Nair, Vijay [Katy, TX; Roes, Augustinus Wilhelmus Maria [Houston, TX

    2011-12-06

    A method of producing methane is described. The method includes providing formation fluid from a subsurface in situ conversion process. The formation fluid is separated to produce a liquid stream and a first gas stream. The first gas stream includes olefins. At least the olefins in the first gas stream are contacted with a hydrogen source in the presence of one or more catalysts and steam to produce a second gas stream. The second gas stream is contacted with a hydrogen source in the presence of one or more additional catalysts to produce a third gas stream. The third gas stream includes methane.

  14. In situ gas treatment technology demonstration test plan

    International Nuclear Information System (INIS)

    Thornton, E.C.; Miller, R.D.

    1996-01-01

    This document defines the objectives and requirements associated with undertaking a field demonstration of an in situ gas treatment appoach to remediation chromate-contaminated soil. The major tasks presented in this plan include the design and development of the surface gas treatment system, performance of permitting activities, and completion of site preparation and field testing activities

  15. Method for local temperature measurement in a nanoreactor for in situ high-resolution electron microscopy.

    Science.gov (United States)

    Vendelbo, S B; Kooyman, P J; Creemer, J F; Morana, B; Mele, L; Dona, P; Nelissen, B J; Helveg, S

    2013-10-01

    In situ high-resolution transmission electron microscopy (TEM) of solids under reactive gas conditions can be facilitated by microelectromechanical system devices called nanoreactors. These nanoreactors are windowed cells containing nanoliter volumes of gas at ambient pressures and elevated temperatures. However, due to the high spatial confinement of the reaction environment, traditional methods for measuring process parameters, such as the local temperature, are difficult to apply. To address this issue, we devise an electron energy loss spectroscopy (EELS) method that probes the local temperature of the reaction volume under inspection by the electron beam. The local gas density, as measured using quantitative EELS, is combined with the inherent relation between gas density and temperature, as described by the ideal gas law, to obtain the local temperature. Using this method we determined the temperature gradient in a nanoreactor in situ, while the average, global temperature was monitored by a traditional measurement of the electrical resistivity of the heater. The local gas temperatures had a maximum of 56 °C deviation from the global heater values under the applied conditions. The local temperatures, obtained with the proposed method, are in good agreement with predictions from an analytical model. Copyright © 2013 Elsevier B.V. All rights reserved.

  16. In-situ solidification cleans up old gas plant site

    International Nuclear Information System (INIS)

    Hatfield, A.D.; Dennis, N.D.

    1995-01-01

    A manufactured gas plant site in Columbus, Georgia, was the location of an environmental cleanup in 1992. Manufactured gas was produced at this site from 1854 to 1931 with the availability of natural gas from a transmission pipeline causing its demise. However, waste products, primarily coal tar from the earlier years of plant operation, remained with the site. In-situ solidification was chosen as the cleanup method. Post monitoring activities show that the project was successful and the site is now a park and a leading part of river front development

  17. Stability of gas atomized reactive powders through multiple step in-situ passivation

    Science.gov (United States)

    Anderson, Iver E.; Steinmetz, Andrew D.; Byrd, David J.

    2017-05-16

    A method for gas atomization of oxygen-reactive reactive metals and alloys wherein the atomized particles are exposed as they solidify and cool in a very short time to multiple gaseous reactive agents for the in-situ formation of a protective reaction film on the atomized particles. The present invention is especially useful for making highly pyrophoric reactive metal or alloy atomized powders, such as atomized magnesium and magnesium alloy powders. The gaseous reactive species (agents) are introduced into the atomization spray chamber at locations downstream of a gas atomizing nozzle as determined by the desired powder or particle temperature for the reactions and the desired thickness of the reaction film.

  18. Temperature of gas delivered from ventilators.

    Science.gov (United States)

    Chikata, Yusuke; Onodera, Mutsuo; Imanaka, Hideaki; Nishimura, Masaji

    2013-01-01

    Although heated humidifiers (HHs) are the most efficient humidifying device for mechanical ventilation, some HHs do not provide sufficient humidification when the inlet temperature to the water chamber is high. Because portable and home-care ventilators use turbines, blowers, pistons, or compressors to inhale in ambient air, they may have higher gas temperature than ventilators with piping systems. We carried out a bench study to investigate the temperature of gas delivered from portable and home-care ventilators, including the effects of distance from ventilator outlet, fraction of inspiratory oxygen (FIO2), and minute volume (MV). We evaluated five ventilators equipped with turbine, blower, piston, or compressor system. Ambient air temperature was adjusted to 24°C ± 0.5°C, and ventilation was set at FIO2 0.21, 0.6, and 1.0, at MV 5 and 10 L/min. We analyzed gas temperature at 0, 40, 80, and 120 cm from ventilator outlet and altered ventilator settings. While temperature varied according to ventilators, the outlet gas temperature of ventilators became stable after, at the most, 5 h. Gas temperature was 34.3°C ± 3.9°C at the ventilator outlet, 29.5°C ± 2.2°C after 40 cm, 25.4°C ± 1.2°C after 80 cm and 25.1°C ± 1.2°C after 120 cm (P < 0.01). FIO2 and MV did not affect gas temperature. Gas delivered from portable and home-care ventilator was not too hot to induce heated humidifier malfunctioning. Gas soon declined when passing through the limb.

  19. Immediate assessment of in situ gas content using underground manometric desorbometer

    Energy Technology Data Exchange (ETDEWEB)

    Lunaezewski, L.W.; Mahoney, M.R. [Lunagas Pty. Ltd., Newcastle, NSW (Australia)

    1995-12-31

    An underground assessment of gas content (within 30 minutes) can be used as a complementary method for the immediate establishment of the magnitudes of in situ gas content at a distance of 5 to 6 metres ahead of a heading face. The indirect method of in situ gas content measurement, using a manometric desorbometer, can be used to establish the direct relationship between underground desorbometer readings and corresponding in situ gas content values for a selected coal seam. 3 refs., 3 figs.

  20. Medium temperature carbon dioxide gas turbine reactor

    International Nuclear Information System (INIS)

    Kato, Yasuyoshi; Nitawaki, Takeshi; Muto, Yasushi

    2004-01-01

    A carbon dioxide (CO 2 ) gas turbine reactor with a partial pre-cooling cycle attains comparable cycle efficiencies of 45.8% at medium temperature of 650 deg. C and pressure of 7 MPa with a typical helium (He) gas turbine reactor of GT-MHR (47.7%) at high temperature of 850 deg. C. This higher efficiency is ascribed to: reduced compression work around the critical point of CO 2 ; and consideration of variation in CO 2 specific heat at constant pressure, C p , with pressure and temperature into cycle configuration. Lowering temperature to 650 deg. C provides flexibility in choosing materials and eases maintenance through the lower diffusion leak rate of fission products from coated particle fuel by about two orders of magnitude. At medium temperature of 650 deg. C, less expensive corrosion resistant materials such as type 316 stainless steel are applicable and their performance in CO 2 have been proven during extensive operation in AGRs. In the previous study, the CO 2 cycle gas turbomachinery weight was estimated to be about one-fifth compared with He cycles. The proposed medium temperature CO 2 gas turbine reactor is expected to be an alternative solution to current high-temperature He gas turbine reactors

  1. Quantification of in situ temperature measurements on a PBI-based high temperature PEMFC unit cell

    DEFF Research Database (Denmark)

    Lebæk, Jesper; Ali, Syed Talat; Møller, Per

    2010-01-01

    The temperature is a very important operating parameter for all types of fuel cells. In the present work distributed in situ temperature measurements are presented on a polybenzimidazole based high temperature PEM fuel cell (HT-PEM). A total of 16 T-type thermocouples were embedded on both the an...

  2. In Situ Raman Analyses of Natural Gas and Gas Hydrates at Hydrate Ridge, Oregon

    Science.gov (United States)

    Peltzer, E. T.; White, S. N.; Dunk, R. M.; Brewer, P. G.; Sherman, A. D.; Schmidt, K.; Hester, K. C.; Sloan, E. D.

    2004-12-01

    During a July 2004 cruise to Hydrate Ridge, Oregon, MBARI's sea-going laser Raman spectrometer was used to obtain in situ Raman spectra of natural gas hydrates and natural gas venting from the seafloor. This was the first in situ analysis of gas hydrates on the seafloor. The hydrate spectra were compared to laboratory analyses performed at the Center for Hydrate Research, Colorado School of Mines. The natural gas spectra were compared to MBARI gas chromatography (GC) analyses of gas samples collected at the same site. DORISS (Deep Ocean Raman In Situ Spectrometer) is a laboratory model laser Raman spectrometer from Kaiser Optical Systems, Inc modified at MBARI for deployment in the deep ocean. It has been successfully deployed to depths as great as 3600 m. Different sampling optics provide flexibility in adapting the instrument to a particular target of interest. An immersion optic was used to analyze natural gas venting from the seafloor at South Hydrate Ridge ( ˜780 m depth). An open-bottomed cube was placed over the vent to collect the gas. The immersion optic penetrated the side of the cube as did a small heater used to dissociate any hydrate formed during sample collection. To analyze solid hydrates at both South and North Hydrate Ridge ( ˜590 m depth), chunks of hydrate were excavated from the seafloor and collected in a glass cylinder with a mesh top. A stand-off optic was used to analyze the hydrate inside the cylinder. Due to the partial opacity of the hydrate and the small focal volume of the sampling optic, a precision underwater positioner (PUP) was used to focus the laser spot onto the hydrate. PUP is a stand-alone system with three degrees-of-freedom, capable of moving the DORISS probe head with a precision of 0.1 mm. In situ Raman analyses of the gas indicate that it is primarily methane. This is verified by GC analyses of samples collected from the same site. Other minor constituents (such as CO2 and higher hydrocarbons) are present but may be in

  3. Cross-check of ex-situ and in-situ metrology of a bendable temperature stabilized KB mirror

    International Nuclear Information System (INIS)

    Yuan Sheng; Goldberg, Kenneth A.; Yashchuk, Valeriy V.; Celestre, Richard; McKinney, Wayne R.; Morrison, Gregory; Macdougall, James; Mochi, Iacopo; Warwick, Tony

    2011-01-01

    At the Advanced Light Source (ALS), we are developing broadly applicable, high-accuracy, in-situ, at-wavelength wavefront slope measurement techniques for Kirkpatrick-Baez (KB) mirror nano-focusing. In this paper, we report an initial cross-check of ex-situ and in-situ metrology of a bendable temperature stabilized KB mirror. This cross-check provides a validation of the in-situ shearing interferometry, currently under development at the ALS.

  4. Resonant optical transducers for in-situ gas detection

    Energy Technology Data Exchange (ETDEWEB)

    Bond, Tiziana C.; Cole, Garrett; Goddard, Lynford

    2018-01-30

    Configurations for in-situ gas detection are provided, and include miniaturized photonic devices, low-optical-loss, guided-wave structures and state-selective adsorption coatings. High quality factor semiconductor resonators have been demonstrated in different configurations, such as micro-disks, micro-rings, micro-toroids, and photonic crystals with the properties of very narrow NIR transmission bands and sensitivity up to 10.sup.-9 (change in complex refractive index). The devices are therefore highly sensitive to changes in optical properties to the device parameters and can be tunable to the absorption of the chemical species of interest. Appropriate coatings applied to the device enhance state-specific molecular detection.

  5. Resonant optical transducers for in-situ gas detection

    Science.gov (United States)

    Bond, Tiziana C; Cole, Garrett; Goddard, Lynford

    2016-06-28

    Configurations for in-situ gas detection are provided, and include miniaturized photonic devices, low-optical-loss, guided-wave structures and state-selective adsorption coatings. High quality factor semiconductor resonators have been demonstrated in different configurations, such as micro-disks, micro-rings, micro-toroids, and photonic crystals with the properties of very narrow NIR transmission bands and sensitivity up to 10.sup.-9 (change in complex refractive index). The devices are therefore highly sensitive to changes in optical properties to the device parameters and can be tunable to the absorption of the chemical species of interest. Appropriate coatings applied to the device enhance state-specific molecular detection.

  6. In Situ Monitoring of Temperature inside Lithium-Ion Batteries by Flexible Micro Temperature Sensors

    Directory of Open Access Journals (Sweden)

    Pei-Chi Chen

    2011-10-01

    Full Text Available Lithium-ion secondary batteries are commonly used in electric vehicles, smart phones, personal digital assistants (PDA, notebooks and electric cars. These lithium-ion secondary batteries must charge and discharge rapidly, causing the interior temperature to rise quickly, raising a safety issue. Over-charging results in an unstable voltage and current, causing potential safety problems, such as thermal runaways and explosions. Thus, a micro flexible temperature sensor for the in in-situ monitoring of temperature inside a lithium-ion secondary battery must be developed. In this work, flexible micro temperature sensors were integrated into a lithium-ion secondary battery using the micro-electro-mechanical systems (MEMS process for monitoring temperature in situ.

  7. Temperature dependence of gas sensing behaviour of TiO2 doped PANI composite thin films

    Science.gov (United States)

    Srivastava, Subodh; Sharma, S. S.; Sharma, Preetam; Sharma, Vinay; Rajura, Rajveer Singh; Singh, M.; Vijay, Y. K.

    2014-04-01

    In the present work we have reported the effect of temperature on the gas sensing properties of TiO2 doped PANI composite thin film based chemiresistor type gas sensors for hydrogen gas sensing application. PANI and TiO2 doped PANI composite were synthesized by in situ chemical oxidative polymerization of aniline at low temperature. The electrical properties of these composite thin films were characterized by I-V measurements as function of temperature. The I-V measurement revealed that conductivity of composite thin films increased as the temperature increased. The changes in resistance of the composite thin film sensor were utilized for detection of hydrogen gas. It was observed that at room temperature TiO2 doped PANI composite sensor shows higher response value and showed unstable behavior as the temperature increased. The surface morphology of these composite thin films has also been characterized by scanning electron microscopy (SEM) measurement.

  8. IAEA high temperature gas cooled reactor activities

    International Nuclear Information System (INIS)

    Kendall, J.M.

    2001-01-01

    IAEA activities on high temperature gas cooled reactors are conducted with the review and support of Member States, primarily through the International Working Group on Gas Cooled Reactors (IWGGCR). This paper summarises the results of the IAEA gas cooled reactor project activities in recent years along with ongoing current activities through a review of Co-ordinated Research Projects (CRPs), meetings and other international efforts. A series of three recently completed CRPs have addressed the key areas of reactor physics for LEU fuel, retention of fission products, and removal of post shutdown decay heat through passive heat transport mechanisms. These activities along with other completed and ongoing supporting CRPs and meetings are summarised with reference to detailed documentation of the results. (author)

  9. High temperature gas cooled nuclear reactor

    International Nuclear Information System (INIS)

    Hosegood, S.B.; Lockett, G.E.

    1975-01-01

    For high-temperature gas cooled reactors it is considered advantageous to design the core so that the moderator blocks can be removed and replaced by some means of standpipes normally situated in the top of the reactor vessel. An arrangement is here described to facilitate these operations. The blocks have end faces shaped as irregular hexagons with three long sides of equal length and three short sides also of equal length, one short side being located between each pair of adjacent long sides, and the long sides being inclined towards one another at 60 0 . The block defines a number of coolant channels located parallel to its sides. Application of the arrangement to a high temperature gas-cooled reactor with refuelling standpipes is described. The standpipes are located in the top of the reactor vessel above the tops of the columns and are disposed coaxially above the hexagonal channels, with diameters that allow the passage of the blocks. (U.K.)

  10. In situ response time measurements of RTD temperature sensors

    International Nuclear Information System (INIS)

    Goncalves, I.M.P.

    1985-01-01

    The loop-current-step-response test provides a mean for determining the time constant of resistence thermometers. The test consist in heating the sensor a few degrees above ambient temperature by causing a step pertubation in the electric current that flows through the sensor leads. The developed mathematical transformation permits to use data collected during the internal heating transient to predict the sensor response to perturbations in fluid temperature. Experimental data obtained show that the time constant determined by method is within 15 percent of true value. The loop-current-step-response test is a remote in situ test, which can be performed with the sensor installed in the process. Consequently it takes account the local heat transfer conditions, and appropriated for nuclear power plants, where sensors are installed in points of difficult access. (author) [pt

  11. The modular high temperature gas cooled reactor

    International Nuclear Information System (INIS)

    Lutz, D.E.; Lipps, A.J.

    1984-01-01

    Due to relatively high operating temperatures, the gas-cooled reactor has the potential to serve a wide variety of energy applications. This paper discusses the energy applications which can be served by the modular HTGR, the magnitude of the potential markets, and the HTGR product cost incentives relative to fossil fuel competition. Advantages of the HTGR modular systems are presented along with a description of the design features and performance characteristics of the current reference HTGR modular systems

  12. Rotational temperature determinations in molecular gas lasers

    International Nuclear Information System (INIS)

    Weaver, L.A.; Taylor, L.H.; Denes, L.J.

    1975-01-01

    The small-signal gain expressions for vibrational-rotational transitions are examined in detail to determine possible methods of extracting the rotational temperature from experimental gain measurements in molecular gas lasers. Approximate values of T/subr/ can be deduced from the rotational quantum numbers for which the P- and R-branch gains are maximum. Quite accurate values of T/subr/ and the population inversion density (n/subv//sub prime/-n/subv//sub double-prime/) can be determined by fitting data to suitably linearized gain relationships, or by performing least-squares fits of the P- and R-branch experimental data to the full gain expressions. Experimental gain measurements for 15 P-branch and 12 R-branch transitions in the 10.4-μm CO 2 band have been performed for pulsed uv-preionized laser discharges in CO 2 : N 2 : He=1 : 2 : 3 mixtures at 600 Torr. These data are subjected to the several gain analyses described herein, yielding a rotational temperature of 401plus-or-minus10 degreeK and an inversion density of (3.77plus-or-minus0.07) times10 17 cm -3 for conditions of maximum gain. These techniques provide accurate values of the gas temperature in molecular gas lasers with excellent temporal and spatial resolution, and should be useful in extending the conversion efficiency and arcing limits of high-energy electrically exc []ted lasers

  13. Novel High Temperature Materials for In-Situ Sensing Devices

    Energy Technology Data Exchange (ETDEWEB)

    Florian Solzbacher; Anil Virkar; Loren Rieth; Srinivasan Kannan; Xiaoxin Chen; Hannwelm Steinebach

    2009-12-31

    The overriding goal of this project was to develop gas sensor materials and systems compatible with operation at temperatures from 500 to 700 C. Gas sensors operating at these temperatures would be compatible with placement in fossil-energy exhaust streams close to the combustion chamber, and therefore have advantages for process regulation, and feedback for emissions controls. The three thrusts of our work included investigating thin film gas sensor materials based on metal oxide materials and electroceramic materials, and also development of microhotplate devices to support the gas sensing films. The metal oxide materials NiO, In{sub 2}O{sub 3}, and Ga{sub 2}O{sub 3} were investigated for their sensitivity to H{sub 2}, NO{sub x}, and CO{sub 2}, respectively, at high temperatures (T > 500 C), where the sensing properties of these materials have received little attention. New ground was broken in achieving excellent gas sensor responses (>10) for temperatures up to 600 C for NiO and In{sub 2}O{sub 3} materials. The gas sensitivity of these materials was decreasing as temperatures increased above 500 C, which indicates that achieving strong sensitivities with these materials at very high temperatures (T {ge} 650 C) will be a further challenge. The sensitivity, selectivity, stability, and reliability of these materials were investigated across a wide range of deposition conditions, temperatures, film thickness, as using surface active promoter materials. We also proposed to study the electroceramic materials BaZr{sub (1-x)}Y{sub x}O{sub (3-x/2)} and BaCe{sub (2-x)}Ca{sub x}S{sub (4-x/2)} for their ability to detect H{sub 2}O and H{sub 2}S, respectively. This report focuses on the properties and gas sensing characteristics of BaZr{sub (1-x)}Y{sub x}O{sub (3-x/2)} (Y-doped BaZrO{sub 3}), as significant difficulties were encounter in generating BaCe{sub (2-x)}Ca{sub x}S{sub (4-x/2)} sensors. Significant new results were achieved for Y-doped BaZrO{sub 3}, including

  14. [Study of the phase transformation of TiO2 with in-situ XRD in different gas].

    Science.gov (United States)

    Ma, Li-Jing; Guo, Lie-Jin

    2011-04-01

    TiO2 sample was prepared by sol-gel method from chloride titanium. The phase transformation of the prepared TiO2 sample was studied by in-situ XRD and normal XRD in different gas. The experimental results showed that the phase transformation temperatures of TiO2 were different under in-situ or normal XRD in different kinds of gas. The transformation of amorphous TiO2 to anatase was controlled by kinetics before 500 degrees C. In-situ XRD showed that the growth of anatase was inhibited, but the transformation of anatase to rutile was accelerated under inactive nitrogen in contrast to air. Also better crystal was obtained under hydrogen than in argon. These all showed that external oxygen might accelerate the growth of TiO2, but reduced gas might partly counteract the negative influence of lack of external oxygen. The mechanism of phase transformation of TiO2 was studied by in-situ XRD in order to control the structure in situ.

  15. High temperature gas-cooled reactor: gas turbine application study

    International Nuclear Information System (INIS)

    1980-12-01

    The high-temperature capability of the High-Temperature Gas-Cooled Reactor (HTGR) is a distinguishing characteristic which has long been recognized as significant both within the US and within foreign nuclear energy programs. This high-temperature capability of the HTGR concept leads to increased efficiency in conventional applications and, in addition, makes possible a number of unique applications in both electrical generation and industrial process heat. In particular, coupling the HTGR nuclear heat source to the Brayton (gas turbine) Cycle offers significant potential benefits to operating utilities. This HTGR-GT Application Study documents the effort to evaluate the appropriateness of the HTGR-GT as an HTGR Lead Project. The scope of this effort included evaluation of the HTGR-GT technology, evaluation of potential HTGR-GT markets, assessment of the economics of commercial HTGR-GT plants, and evaluation of the program and expenditures necessary to establish HTGR-GT technology through the completion of the Lead Project

  16. High temperature gas-cooled reactor: gas turbine application study

    Energy Technology Data Exchange (ETDEWEB)

    1980-12-01

    The high-temperature capability of the High-Temperature Gas-Cooled Reactor (HTGR) is a distinguishing characteristic which has long been recognized as significant both within the US and within foreign nuclear energy programs. This high-temperature capability of the HTGR concept leads to increased efficiency in conventional applications and, in addition, makes possible a number of unique applications in both electrical generation and industrial process heat. In particular, coupling the HTGR nuclear heat source to the Brayton (gas turbine) Cycle offers significant potential benefits to operating utilities. This HTGR-GT Application Study documents the effort to evaluate the appropriateness of the HTGR-GT as an HTGR Lead Project. The scope of this effort included evaluation of the HTGR-GT technology, evaluation of potential HTGR-GT markets, assessment of the economics of commercial HTGR-GT plants, and evaluation of the program and expenditures necessary to establish HTGR-GT technology through the completion of the Lead Project.

  17. Two methods to measure granular gas temperature

    Science.gov (United States)

    Chastaing, J.-Y.; Géminard, J.-C.; Naert, A.

    2017-07-01

    Grains are vibrated so as to achieve a granular gas, here regarded as an archetype of a dissipative non equilibrium steady state (NESS). We report on two distinct and concordant experimental measures of the system effective temperature. To do so, a blade fastened to the shaft of a small DC-motor, immersed in the grains, behaves as a driven 1D Brownian rotator, which is used as both actuator and sensor simultaneously. On the one hand, the Gallavotti-Cohen fluctuation theorem, which involves a measure of the asymmetry of the energy exchanges between the rotator and the NESS reservoir, provides a first effective temperature. On the other hand, the fluctuation-dissipation theorem, which involves the relation between the spontaneous fluctuations and the response to a weak perturbation, defines a second, independent, effective temperature. Both methods, even though they are based on drastically different ideas, give nicely concordant results.

  18. The development of an electrochemical technique for in situ calibrating of combustible gas detectors

    Science.gov (United States)

    Shumar, J. W.; Lantz, J. B.; Schubert, F. H.

    1976-01-01

    A program to determine the feasibility of performing in situ calibration of combustible gas detectors was successfully completed. Several possible techniques for performing the in situ calibration were proposed. The approach that showed the most promise involved the use of a miniature water vapor electrolysis cell for the generation of hydrogen within the flame arrestor of a combustible gas detector to be used for the purpose of calibrating the combustible gas detectors. A preliminary breadboard of the in situ calibration hardware was designed, fabricated and assembled. The breadboard equipment consisted of a commercially available combustible gas detector, modified to incorporate a water vapor electrolysis cell, and the instrumentation required for controlling the water vapor electrolysis and controlling and calibrating the combustible gas detector. The results showed that operation of the water vapor electrolysis at a given current density for a specific time period resulted in the attainment of a hydrogen concentration plateau within the flame arrestor of the combustible gas detector.

  19. Bimodular high temperature planar oxygen gas sensor

    Directory of Open Access Journals (Sweden)

    Xiangcheng eSun

    2014-08-01

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

  20. In-situ tritium recovery from Li2O irradiated in fast neutron flux - Beatrix-II temperature change specimen

    International Nuclear Information System (INIS)

    Slagle, O.D.; Hollenberg, G.W.; Kurasawa, T.; Verrall, R.A.

    1992-01-01

    The Beatrix-II irradiation experiment is an in-situ tritium release experiment to evaluate the stability and tritium release characteristics of Li 2 O under fast neutron irradiation to extended burnups. A thin annular ring specimen capable of temperature changes was irradiated in Phase I of the experiment to a lithium burnup of 5%. The primary emphasis of the test plan was to determine the effect and interrelationship of gas composition and temperature on the tritium inventory with increasing temperature and a series of specific temperature changes were carried out at intervals throughout the experiment to characterize the effect of burnup. Decreasing the amount of hydrogen in the sweep gas resulted in an increase in the tritium inventory in the Li 2 O specimen. The tritium recovery during startup and shutdown was observed to be strongly influenced by the composition of the sweep gas

  1. WindBots: persistent in-situ science explorers for gas giants

    Data.gov (United States)

    National Aeronautics and Space Administration — We envision persistent exploration of the gas giants with robots powered by locally harvested energy, performing in-situ observational atmospheric science. Riding...

  2. Comparison between in situ dry matter degradation and in vitro gas ...

    African Journals Online (AJOL)

    Dry matter (DM) degradation of Glycrrhiza glabra L, Arbutus andrachne, Juniperus communis, and Pistica lentiscus was determined using two different techniques: (i) the in vitro gas production and (ii) the in situ nylon bag degradability technique. Samples were incubated in situ and in vitro for 3, 6, 12, 24, 48, 72 and 96 h.

  3. Off-gas treatment and characterization for a radioactive in situ vitrification test

    International Nuclear Information System (INIS)

    Oma, K.H.; Timmerman, C.L.

    1985-01-01

    Effluents released to the off gas during the in situ vitrification (ISV) of a test site have been characterized. The site consisted of a 19 L waste package of soil containing 600 nCi/g transuranic and 30,000 nCi/g mixed fission products surrounded by uncontaminated soil. Radioactive isotopes present in the package were 241 Am, /sup 238/239/Pu, 137 Cs, 106 Ru, 90 Sr, and 60 Co. The ISV process melted the waste package and surrounding soil and immobilized the radionuclides in place, producing a durable, 8.6 metric ton glass and crystalline monolith. The test successfully demonstrated that the process provides containment of radioactive material. No release to the environment was detected during processing or cooldown. Due to the high temperatures during processing, some gases were released into the off-gas hood that was placed over the test site. The hood was maintained at a light negative pressure to contain any volatile or entrained material during processing. Gases passed from the hood to an off-gas treatment system where they were treated using a venturi-ejector scrubber, a tandem nozzle gas cleaner scrubber followed by a condenser, heater, and two stages of HEPA filters. The off-gas treatment system is located in the semi-trailer to allow transport of the process to other potential test sites. Retention of all radionuclides by the vitrified zone was greater than 99%. Soil-to-off-gas decontamination factors (DFs) for transuranic elements averaged greater than 4000 and for fission products, DFs ranged from 130 for 137 Cs to 3100 for 90 Sr

  4. Off-gas treatment and characterization for a radioactive in situ vitrification test

    International Nuclear Information System (INIS)

    Oma, K.H.; Timmerman, C.L.

    1984-08-01

    Effluents released to the off gas during the in situ vitrification (ISV) of a test site have been characterized by Pacific Northwest Laboratory. The site consisted of a 19 L waste package of soil containing 600 nCi/g transuranic and 30,000 nCi/g mixed fission products surrounded by uncontaminated soil. Radioactive isotopes present in the package were 241 Am, 238 / 239 Pu, 137 Cs, 106 Ru, 90 Sr, and 60 Co. The ISV process melted the waste package and surrounding soil and immobilized the radionuclides in place, producing a durable, 8.6 metric ton glass and crystalline monolith. The test successfully demonstrated that the process provides containment of radioactive material. No release to the environment was detected during processing of cooldown. Due to the high temperature during processing, some gases were released into the off-gas hood that was over the test site. The hood was maintained at a slight negative pressure to contain any volatile or entrained material during processing. Gases passed from the hood to an off-gas treatment system where they were treated using a venturi-ejector scrubber, a tandem nozzle gas cleaner scrubber followed by a condenser, heater, and two stages of HEPA filters. The off-gas treatment system is located in the semi-trailer to allow transport of the process to other potential test sites. Retention of all radionuclides by the vitrified zone was greater than 99%. Soil-to-off-gas decontamination factors (DFs) for transuranic elements averaged greater than 4000 and for fission products, DFs ranged from 130 for 137 Cs to 3100 for 90 Sr. 7 references, 15 figures, 4 tables

  5. Manipulation of Samples at Extreme Temperatures for Fast in-situ Synchrotron Measurements

    Energy Technology Data Exchange (ETDEWEB)

    Weber, Richard [Materials Development, Inc., Arlington Heights, IL (United States)

    2016-04-22

    An aerodynamic sample levitation system with laser beam heating was integrated with the APS beamlines 6 ID-D, 11 ID-C and 20 BM-B. The new capability enables in-situ measurements of structure and XANES at extreme temperatures (300-3500 °C) and in conditions that completely avoid contact with container surfaces. In addition to maintaining a high degree of sample purity, the use of aerodynamic levitation enables deep supercooling and greatly enhanced glass formation from a wide variety of melts and liquids. Development and integration of controlled extreme sample environments and new measurement techniques is an important aspect of beamline operations and user support. Processing and solidifying liquids is a critical value-adding step in manufacturing semiconductors, optical materials, metals and in the operation of many energy conversion devices. Understanding structural evolution is of fundamental importance in condensed materials, geology, and biology. The new capability provides unique possibilities for materials research and helps to develop and maintain a competitive materials manufacturing and energy utilization industry. Test samples were used to demonstrate key features of the capability including experiments on hot crystalline materials, liquids at temperatures from about 500 to 3500 °C. The use of controlled atmospheres using redox gas mixtures enabled in-situ changes in the oxidation states of cations in melts. Significant innovations in this work were: (i) Use of redox gas mixtures to adjust the oxidation state of cations in-situ (ii) Operation with a fully enclosed system suitable for work with nuclear fuel materials (iii) Making high quality high energy in-situ x-ray diffraction measurements (iv) Making high quality in-situ XANES measurements (v) Publishing high impact results (vi) Developing independent funding for the research on nuclear materials This SBIR project work led to a commercial instrument product for the niche market of processing and

  6. Development of an in situ calibration technique for combustible gas detectors

    Science.gov (United States)

    Shumar, J. W.; Wynveen, R. A.; Lance, N., Jr.; Lantz, J. B.

    1977-01-01

    This paper describes the development of an in situ calibration procedure for combustible gas detectors (CGD). The CGD will be a necessary device for future space vehicles as many subsystems in the Environmental Control/Life Support System utilize or produce hydrogen (H2) gas. Existing calibration techniques are time-consuming and require support equipment such as an environmental chamber and calibration gas supply. The in situ calibration procedure involves utilization of a water vapor electrolysis cell for the automatic in situ generation of a H2/air calibration mixture within the flame arrestor of the CGD. The development effort concluded with the successful demonstration of in situ span calibrations of a CGD.

  7. Evaluation of MODIS Land Surface Temperature with In Situ Snow Surface Temperature from CREST-SAFE

    Science.gov (United States)

    Perez Diaz, C. L.; Lakhankar, T.; Romanov, P.; Munoz, J.; Khanbilvardi, R.; Yu, Y.

    2016-12-01

    This paper presents the procedure and results of a temperature-based validation approach for the Moderate Resolution Imaging Spectroradiometer (MODIS) Land Surface Temperature (LST) product provided by the National Aeronautics and Space Administration (NASA) Terra and Aqua Earth Observing System satellites using in situ LST observations recorded at the Cooperative Remote Sensing Science and Technology Center - Snow Analysis and Field Experiment (CREST-SAFE) during the years of 2013 (January-April) and 2014 (February-April). A total of 314 day and night clear-sky thermal images, acquired by the Terra and Aqua satellites, were processed and compared to ground-truth data from CREST-SAFE with a frequency of one measurement every 3 min. Additionally, this investigation incorporated supplementary analyses using meteorological CREST-SAFE in situ variables (i.e. wind speed, cloud cover, incoming solar radiation) to study their effects on in situ snow surface temperature (T-skin) and T-air. Furthermore, a single pixel (1km2) and several spatially averaged pixels were used for satellite LST validation by increasing the MODIS window size to 5x5, 9x9, and 25x25 windows for comparison. Several trends in the MODIS LST data were observed, including the underestimation of daytime values and nighttime values. Results indicate that, although all the data sets (Terra and Aqua, diurnal and nocturnal) showed high correlation with ground measurements, day values yielded slightly higher accuracy ( 1°C), both suggesting that MODIS LST retrievals are reliable for similar land cover classes and atmospheric conditions. Results from the CREST-SAFE in situ variables' analyses indicate that T-air is commonly higher than T-skin, and that a lack of cloud cover results in: lower T-skin and higher T-air minus T-skin difference (T-diff). Additionally, the study revealed that T-diff is inversely proportional to cloud cover, wind speed, and incoming solar radiation. Increasing the MODIS window size

  8. In-situ gas hydrate hydrate saturation estimated from various well logs at the Mount Elbert Gas Hydrate Stratigraphic Test Well, Alaska North Slope

    Science.gov (United States)

    Lee, M.W.; Collett, T.S.

    2011-01-01

    In 2006, the U.S. Geological Survey (USGS) completed detailed analysis and interpretation of available 2-D and 3-D seismic data and proposed a viable method for identifying sub-permafrost gas hydrate prospects within the gas hydrate stability zone in the Milne Point area of northern Alaska. To validate the predictions of the USGS and to acquire critical reservoir data needed to develop a long-term production testing program, a well was drilled at the Mount Elbert prospect in February, 2007. Numerous well log data and cores were acquired to estimate in-situ gas hydrate saturations and reservoir properties.Gas hydrate saturations were estimated from various well logs such as nuclear magnetic resonance (NMR), P- and S-wave velocity, and electrical resistivity logs along with pore-water salinity. Gas hydrate saturations from the NMR log agree well with those estimated from P- and S-wave velocity data. Because of the low salinity of the connate water and the low formation temperature, the resistivity of connate water is comparable to that of shale. Therefore, the effect of clay should be accounted for to accurately estimate gas hydrate saturations from the resistivity data. Two highly gas hydrate-saturated intervals are identified - an upper ???43 ft zone with an average gas hydrate saturation of 54% and a lower ???53 ft zone with an average gas hydrate saturation of 50%; both zones reach a maximum of about 75% saturation. ?? 2009.

  9. Relationship between in situ degradation kinetics and in vitro gas production fermentation using different mathematical models

    NARCIS (Netherlands)

    Rodrigues, M.A.M.; Cone, J.W.; Ferreira, L.M.M.; Blok, M.C.; Guedes, C.

    2009-01-01

    In vitro and in situ studies were conducted to evaluate the influence of different mathematical models, used to fit gas production profiles of 15 feedstuffs, on estimates of nylon bag organic matter (OM) degradation kinetics. The gas production data were fitted to Exponential, Logistic, Gompertz and

  10. A flexible gas flow reaction cell for in situ x-ray absorption spectroscopy studies

    Energy Technology Data Exchange (ETDEWEB)

    Kroner, Anna B., E-mail: anna.kroner@diamond.ac.uk; Gilbert, Martin; Duller, Graham; Cahill, Leo; Leicester, Peter; Woolliscroft, Richard; Shotton, Elizabeth J. [Diamond Light Source Ltd., Diamond House, Harwell Science and Innovation Campus, Chilton, Oxfordshire, OX110DE (United Kingdom); Mohammed, Khaled M. H. [UK Catalysis Hub, Research Complex at Harwell, Rutherford Appleton Laboratory, Chilton, Oxfordshire, OX110FA (United Kingdom); School of Chemistry, University of Southampton, Southampton, SO17 1BJ (United Kingdom)

    2016-07-27

    A capillary-based sample environment with hot air blower and integrated gas system was developed at Diamond to conduct X-ray absorption spectroscopy (XAS) studies of materials under time-resolved, in situ conditions. The use of a hot air blower, operating in the temperature range of 298-1173 K, allows introduction of other techniques e.g. X-ray diffraction (XRD), Raman spectroscopy for combined techniques studies. The flexibility to use either quartz or Kapton capillaries allows users to perform XAS measurement at energies as low as 5600 eV. To demonstrate performance, time-resolved, in situ XAS results of Rh catalysts during the process of activation (Rh K-edge, Ce L{sub 3}-edge and Cr K-edge) and the study of mixed oxide membrane (La{sub 0.6}Sr{sub 0.4}Co{sub 0.2}Fe{sub 0.8}O{sub 3−δ}) under various partial oxygen pressure conditions are described.

  11. Gas permeability of thin polyimide foils prepared by in-situ polymerisation

    International Nuclear Information System (INIS)

    Stolarz, Anna; Varlam, Mihai; Wellum, Roger

    2008-01-01

    The entrance windows to the gas detector chambers as well as to the target containers used in high-energy and high-intensity accelerators must be as thin as possible to minimise energy losses of the particles used in astrophysics and nuclear physics studies. Because of their good physical properties, polyimide foils are often considered as suitable material for such windows, but commercially available foils, having a thickness greater than 7-8 μm (>1 mg/cm 2 ), would cause energy losses of particles significant for some nuclear reactions studied. Foils prepared by in-situ polymerisation can, however, be as thin as 0.07 μm (∼10 μg/cm 2 ). The permeability of 4 μm foils produced by in-situ polymerisation has been measured at room temperature for He and Ar. For He measurements were performed in the pressure range of 4-70 mbar and for Ar in the range of 20-140 mbar and the permeability was found to be in good agreement with the values published for the thicker commercial foils

  12. Technology on In-Situ Gas Generation to Recover Residual Oil Reserves

    Energy Technology Data Exchange (ETDEWEB)

    Sayavur Bakhtiyarov

    2008-02-29

    This final technical report covers the period October 1, 1995 to February 29, 2008. This chapter begins with an overview of the history of Enhanced Oil Recovery techniques and specifically, CO2 flood. Subsequent chapters conform to the manner consistent with the Activities, Tasks, and Sub-tasks of the project as originally provided in Exhibit C1 in the Project Management Plan dated September 20, 1995. These chapters summarize the objectives, status and conclusions of the major project activities performed during the project period. The report concludes by describing technology transfer activities stemming from the project and providing a reference list of all publications of original research work generated by the project team or by others regarding this project. The overall objective of this project was a final research and development in the United States a technology that was developed at the Institute for Geology and Development of Fossil Fuels in Moscow, Russia. Before the technology can be convincingly adopted by United States oil and gas producers, the laboratory research was conducted at Mew Mexico Institute of Mining and Technology. The experimental studies were conducted to measure the volume and the pressure of the CO{sub 2} gas generated according to the new Russian technology. Two experimental devices were designed, built and used at New Mexico Tech facilities for these purposes. The designed setup allowed initiating and controlling the reaction between the 'gas-yielding' (GY) and 'gas-forming' (GF) agents proposed by Russian technology. The temperature was controlled, and the generated gas pressure and volume were recorded during the reaction process. Additionally, the effect of surfactant addition on the effectiveness of the process was studied. An alternative GY reactant was tested in order to increase the efficiency of the CO2 gas generation process. The slim tube and the core flood experimental studies were conducted to define

  13. Gas Temperature Measurement in a Glow Discharge Plasma

    Science.gov (United States)

    Sloneker, Kenneth; Podder, Nirmol; McCurdy, William E.; Shi, Shi

    2009-10-01

    In this study a relatively inexpensive quartz protected thermocouple is used to measure the gas temperature in the positive column of a glow discharge plasma. For simplicity a K-type thermocouple is used to interpret the gas temperature from the sensor voltage at pressures from 0.5 Torr to 15 Torr and discharge currents from 5 mA to 120 mA. Gas temperature is investigated as a function of the gas pressure at fixed discharge currents and as a function of discharge current at fixed gas pressures in three different gas species (Ar, N2, and He). An infinite cylinder model is used to compute the average gas temperature of the discharge from joule heating and gas thermal conductivity. The model and measurement data agree within 1% to 10% depending on plasma parameters. Data for all three gases have a similar quasi-linear increasing error as compared to the model.

  14. Effect of In-situ Cure on Measurement of Glass Transition Temperatures in High-temperature Thermosetting Polymers

    Science.gov (United States)

    2015-01-01

    TEMPERATURES IN HIGH-TEMPERATURE THERMOSETTING POLYMERS 5a. CONTRACT NUMBER In-House 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S...illustrated the difficulties inherent in measurement of the glass transition temperature of this high-temperature thermosetting polymer via dynamic...copyright protection in the United States. EFFECT OF IN-SITU CURE ON MEASUREMENT OF GLASS TRANSITION TEMPERATURES IN HIGH-TEMPERATURE THERMOSETTING

  15. Chemical Composition, In Situ Degradability and In Vitro Gas ...

    African Journals Online (AJOL)

    The leguminous tree tagasaste is highly productive in the Ethiopian ... and conservation practices, could substantially change the nutritive value of a given ...... in vitro gas production and stoichiometric relationship between short chain fatty acid ...

  16. Molecular Tagging Velocimetry Development for In-situ Measurement in High-Temperature Test Facility

    Science.gov (United States)

    Andre, Matthieu A.; Bardet, Philippe M.; Burns, Ross A.; Danehy, Paul M.

    2015-01-01

    The High Temperature Test Facility, HTTF, at Oregon State University (OSU) is an integral-effect test facility designed to model the behavior of a Very High Temperature Gas Reactor (VHTR) during a Depressurized Conduction Cooldown (DCC) event. It also has the ability to conduct limited investigations into the progression of a Pressurized Conduction Cooldown (PCC) event in addition to phenomena occurring during normal operations. Both of these phenomena will be studied with in-situ velocity field measurements. Experimental measurements of velocity are critical to provide proper boundary conditions to validate CFD codes, as well as developing correlations for system level codes, such as RELAP5 (http://www4vip.inl.gov/relap5/). Such data will be the first acquired in the HTTF and will introduce a diagnostic with numerous other applications to the field of nuclear thermal hydraulics. A laser-based optical diagnostic under development at The George Washington University (GWU) is presented; the technique is demonstrated with velocity data obtained in ambient temperature air, and adaptation to high-pressure, high-temperature flow is discussed.

  17. Effect of temperature on crack initiation in gas formed structures

    Energy Technology Data Exchange (ETDEWEB)

    Gohari, S.; Vrcelj, Z.; Sharifi, S.; Sharifishourabi, G.; Abadi, R. [Universiti Teknlogi Malaysia, Skudai (Malaysia)

    2013-12-15

    In the gas forming process, the work piece is formed by applying gas pressure. However, the gas pressure and the accompanying gas temperature can result in crack initiation and unstable crack growth. Thus, it is vital to determine the critical values of applied gas pressure and temperature to avoid crack and fracture failure. We studied the mechanism of fracture using an experimental approach and finite element simulations of a perfect aluminum sheet containing no inclusions and voids. The definition of crack was based on ductile damage mechanics. For inspection of initiation of crack and rupture in gas-metal forming, the ABAQUS/EXPLICIT simulation was used. In gas forming, the applied load is the pressure applied rather than the punching force. The results obtained from both the experimental approach and finite element simulations were compared. The effects of various parameters, such as temperature and gas pressure value on crack initiation, were taken into account.

  18. High-temperature Gas Reactor (HTGR)

    Science.gov (United States)

    Abedi, Sajad

    2011-05-01

    General Atomics (GA) has over 35 years experience in prismatic block High-temperature Gas Reactor (HTGR) technology design. During this period, the design has recently involved into a modular have been performed to demonstrate its versatility. This versatility is directly related to refractory TRISO coated - particle fuel that can contain any type of fuel. This paper summarized GA's fuel cycle studies individually and compares each based upon its cycle sustainability, proliferation-resistance capabilities, and other performance data against pressurized water reactor (PWR) fuel cycle data. Fuel cycle studies LEU-NV;commercial HEU-Th;commercial LEU-Th;weapons-grade plutonium consumption; and burning of LWR waste including plutonium and minor actinides in the MHR. results show that all commercial MHR options, with the exception of HEU-TH, are more sustainable than a PWR fuel cycle. With LEU-NV being the most sustainable commercial options. In addition, all commercial MHR options out perform the PWR with regards to its proliferation-resistance, with thorium fuel cycle having the best proliferation-resistance characteristics.

  19. Thermodynamics of a classical ideal gas at arbitrary temperatures

    OpenAIRE

    Pal, Palash B.

    2002-01-01

    We propose a fundamental relation for a classical ideal gas that is valid at all temperatures with remarkable accuracy. All thermodynamical properties of classical ideal gases can be deduced from this relation at arbitrary temperature.

  20. X3 expansion tube driver gas spectroscopy and temperature measurements

    Science.gov (United States)

    Parekh, V.; Gildfind, D.; Lewis, S.; James, C.

    2017-11-01

    The University of Queensland's X3 facility is a large, free-piston driven expansion tube used for super-orbital and high Mach number scramjet aerothermodynamic studies. During recent development of new scramjet test flow conditions, experimentally measured shock speeds were found to be significantly lower than that predicted by initial driver performance calculations. These calculations were based on ideal, isentropic compression of the driver gas and indicated that loss mechanisms, not accounted for in the preliminary analysis, were significant. The critical determinant of shock speed is peak driver gas sound speed, which for a given gas composition depends on the peak driver gas temperature. This temperature may be inaccurately estimated if an incorrect fill temperature is assumed, or if heat losses during driver gas compression are significant but not accounted for. For this study, the ideal predicted peak temperature was 3750 K, without accounting for losses. However, a much lower driver temperature of 2400 K is suggested based on measured experimental shock speeds. This study aimed to measure initial and peak driver gas temperatures for a representative X3 operating condition. Examination of the transient temperatures of the driver gas and compression tube steel wall during the initial fill process showed that once the filling process was complete, the steady-state driver gas temperature closely matched the tube wall temperature. Therefore, while assuming the gas is initially at the ambient laboratory temperature is not a significant source of error, it can be entirely mitigated by simply monitoring tube wall temperature. Optical emission spectroscopy was used to determine the driver gas spectra after diaphragm rupture; the driver gas emission spectrum exhibited a significant continuum radiation component, with prominent spectral lines attributed to contamination of the gas. A graybody approximation of the continuum suggested a peak driver gas temperature of

  1. X3 expansion tube driver gas spectroscopy and temperature measurements

    Science.gov (United States)

    Parekh, V.; Gildfind, D.; Lewis, S.; James, C.

    2018-07-01

    The University of Queensland's X3 facility is a large, free-piston driven expansion tube used for super-orbital and high Mach number scramjet aerothermodynamic studies. During recent development of new scramjet test flow conditions, experimentally measured shock speeds were found to be significantly lower than that predicted by initial driver performance calculations. These calculations were based on ideal, isentropic compression of the driver gas and indicated that loss mechanisms, not accounted for in the preliminary analysis, were significant. The critical determinant of shock speed is peak driver gas sound speed, which for a given gas composition depends on the peak driver gas temperature. This temperature may be inaccurately estimated if an incorrect fill temperature is assumed, or if heat losses during driver gas compression are significant but not accounted for. For this study, the ideal predicted peak temperature was 3750 K, without accounting for losses. However, a much lower driver temperature of 2400 K is suggested based on measured experimental shock speeds. This study aimed to measure initial and peak driver gas temperatures for a representative X3 operating condition. Examination of the transient temperatures of the driver gas and compression tube steel wall during the initial fill process showed that once the filling process was complete, the steady-state driver gas temperature closely matched the tube wall temperature. Therefore, while assuming the gas is initially at the ambient laboratory temperature is not a significant source of error, it can be entirely mitigated by simply monitoring tube wall temperature. Optical emission spectroscopy was used to determine the driver gas spectra after diaphragm rupture; the driver gas emission spectrum exhibited a significant continuum radiation component, with prominent spectral lines attributed to contamination of the gas. A graybody approximation of the continuum suggested a peak driver gas temperature of

  2. Effect of In-Situ Cure on Measurement of Glass Transition Temperatures in High-Temperature Thermosetting Polymers (Briefing Charts)

    Science.gov (United States)

    2015-05-20

    TEMPERATURES IN HIGH-TEMPERATURE THERMOSETTING POLYMERS 5a. CONTRACT NUMBER In-House 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) 5d...temperature thermosetting polymer via dynamic mechanical analysis alone. These difficulties result from the residual cure of samples heated beyond their...98) Prescribed by ANSI Std. 239.18 Effect of In-Situ Cure on Measurement of Glass Transition Temperatures in High-Temperature Thermosetting

  3. Low Temperature Regolith Bricks for In-Situ Structural Material

    Science.gov (United States)

    Grossman, Kevin; Sakthivel, Tamil S.; Mantovani, James; Seal, Sudipta

    2016-01-01

    Current technology for producing in-situ structural materials on future missions to Mars or the moon relies heavily on energy-intensive sintering processes to produce solid bricks from regolith. This process requires heating the material up to temperatures in excess of 1000 C and results in solid regolith pieces with compressive strengths in the range of 14000 to 28000 psi, but are heavily dependent on the porosity of the final material and are brittle. This method is currently preferred over a low temperature cementation process to prevent consumption of precious water and other non-renewable materials. A high strength structural material with low energy requirements is still needed for future colonization of other planets. To fulfill these requirements, a nano-functionalization process has been developed to produce structural bricks from regolith simulant and shows promising mechanical strength results. Functionalization of granular silicate particles into alkoxides using a simple low temperature chemical process produces a high surface area zeolite particles that are held together via inter-particle oxygen bonding. Addition of water in the resulting zeolite particles produces a sol-gel reaction called "inorganic polymerization" which gives a strong solid material after a curing process at 60 C. The aqueous solution by-product of the reaction is currently being investigated for its reusability; an essential component of any ISRU technology. For this study, two batches of regolith bricks are synthesized from JSC-1A; the first batch from fresh solvents and chemicals, the second batch made from the water solution by-product of the first batch. This is done to determine the feasibility of recycling necessary components of the synthesis process, mainly water. Characterization including BET surface area, SEM, and EDS has been done on the regolith bricks as well as the constituent particles,. The specific surface area of 17.53 sq m/g (average) of the granular regolith

  4. Sour gas injection for use with in situ heat treatment

    Science.gov (United States)

    Fowler, Thomas David [Houston, TX

    2009-11-03

    Systems, methods, and heaters for treating a subsurface formation are described herein. At least one method for providing acidic gas to a subsurface formation is described herein. The method may include providing heat from one or more heaters to a portion of a subsurface formation; producing fluids that include one or more acidic gases from the formation using a heat treatment process. At least a portion of one of the acidic gases may be introduced into the formation, or into another formation, through one or more wellbores at a pressure below a lithostatic pressure of the formation in which the acidic gas is introduced.

  5. A new in-situ method to determine the apparent gas diffusion coefficient of soils

    Science.gov (United States)

    Laemmel, Thomas; Paulus, Sinikka; Schack-Kirchner, Helmer; Maier, Martin

    2015-04-01

    Soil aeration is an important factor for the biological activity in the soil and soil respiration. Generally, gas exchange between soil and atmosphere is assumed to be governed by diffusion and Fick's Law is used to describe the fluxes in the soil. The "apparent soil gas diffusion coefficient" represents the proportional factor between the flux and the gas concentration gradient in the soil and reflects the ability of the soil to "transport passively" gases through the soil. One common way to determine this coefficient is to take core samples in the field and determine it in the lab. Unfortunately this method is destructive and needs laborious field work and can only reflect a small fraction of the whole soil. As a consequence insecurity about the resulting effective diffusivity on the profile scale must remain. We developed a new in-situ method using new gas sampling device, tracer gas and inverse soil gas modelling. The gas sampling device contains several sampling depths and can be easily installed into vertical holes of an auger, which allows for fast installation of the system. At the lower end of the device inert tracer gas is injected continuously. The tracer gas diffuses into the surrounding soil. The resulting distribution of the tracer gas concentrations is used to deduce the diffusivity profile of the soil. For Finite Element Modeling of the gas sampling device/soil system the program COMSOL is used. We will present the results of a field campaign comparing the new in-situ method with lab measurements on soil cores. The new sampling pole has several interesting advantages: it can be used in-situ and over a long time; so it allows following modifications of diffusion coefficients in interaction with rain but also vegetation cycle and wind.

  6. In situ droplet surface tension and viscosity measurements in gas metal arc welding

    International Nuclear Information System (INIS)

    Bachmann, B; Siewert, E; Schein, J

    2012-01-01

    In this paper, we present an adaptation of a drop oscillation technique that enables in situ measurements of thermophysical properties of an industrial pulsed gas metal arc welding (GMAW) process. Surface tension, viscosity, density and temperature were derived expanding the portfolio of existing methods and previously published measurements of surface tension in pulsed GMAW. Natural oscillations of pure liquid iron droplets are recorded during the material transfer with a high-speed camera. Frame rates up to 30000 fps were utilized to visualize iron droplet oscillations which were in the low kHz range. Image processing algorithms were employed for edge contour extraction of the droplets and to derive parameters such as oscillation frequencies and damping rates along different dimensions of the droplet. Accurate surface tension measurements were achieved incorporating the effect of temperature on density. These are compared with a second method that has been developed to accurately determine the mass of droplets produced during the GMAW process which enables precise surface tension measurements with accuracies up to 1% and permits the study of thermophysical properties also for metals whose density highly depends on temperature. Thermophysical properties of pure liquid iron droplets formed by a wire with 1.2 mm diameter were investigated in a pulsed GMAW process with a base current of 100 A and a pulse current of 600 A. Surface tension and viscosity of a sample droplet were 1.83 ± 0.02 N m -1 and 2.9 ± 0.3 mPa s, respectively. The corresponding droplet temperature and density are 2040 ± 50 K and 6830 ± 50 kg m -3 , respectively. (paper)

  7. Novel silica membranes for high temperature gas separations

    KAUST Repository

    Bighane, Neha; Koros, William J.

    2011-01-01

    and pure gas separation performance in the temperature range 35-80°C is presented. It is observed that the membranes exhibit activated transport for small gas penetrants such as He, H 2 and CO 2. The membranes can withstand temperatures up to 350°C in air

  8. Hydration of the Atlantis Massif: Halogen, Noble Gas and In-Situ δ18O Constraints

    Science.gov (United States)

    Williams, M. J.; Kendrick, M. A.; Rubatto, D.

    2017-12-01

    A combination of halogen (Cl, Br, I), noble gases (He, Ne, Ar, Kr and Xe) and in situ oxygen isotope analysis have been utilized to investigate the fluid-mobile element record of hydration and alteration processes at the Atlantis Massif (30°N on the Mid-Atlantic Ridge). The sample suite investigated includes serpentinite, talc-amphibole ± chlorite schist and hydrated gabbro recovered by seafloor drilling undertaken at sites on a transect across the Atlantis Massif during IODP Expedition 357. Serpentine mesh and veins analysed in-situ by SHRIMP SI exhibit δ18O from 6‰ down to ≈0‰, suggesting serpentinization temperatures of 150 to >280°C and water/rock ratios >5. Differences of 1.5-2.5‰ are observed between adjacent generations of serpentine, but the δ18O range is similar at each investigated drilling site. Halogen and noble gas abundances in serpentinites, talc-amphibole schist and hydrated gabbro have been measured by noble gas mass spectrometry of both irradiated and non-irradiated samples. Serpentinites contain low abundances of halogens and noble gases (e.g. 70-430 ppm Cl, 4.7-12.2 x 10-14 mol/g 36Ar) relative to other seafloor serpentinites. The samples have systematically different Br/Cl and I/Cl ratios related to their mineralogy. Serpentinites retain mantle-like Br/Cl with a wide variation in I/Cl that stretches toward seawater values. Talc-amphibole schists exhibit depletion of Br and I relative to Cl with increasing Cl abundances, suggesting tremolite exerts strong control on halogen abundance ratios. Serpentinites show no evidence of interaction with halogen-rich sedimentary pore fluids. Iodine abundances are variable across serpentinites, and are decoupled from Br and Cl; iodine enrichment (up to 530 ppb) is observed within relatively oxidised and clay-bearing samples. Serpentinized harzburgites exhibit distinct depletion of Kr and Xe relative to atmospheric 36Ar in seawater. Oxygen isotope compositions and low abundances of both halogens

  9. Measured gas and particle temperatures in VTT's entrained flow reactor

    DEFF Research Database (Denmark)

    Clausen, Sønnik; Sørensen, L.H.

    2006-01-01

    Particle and gas temperature measurements were carried out in experiments on VTTs entrained flow reactor with 5% and 10% oxygen using Fourier transform infrared emission spectroscopy (FTIR). Particle temperature measurements were performed on polish coal,bark, wood, straw particles, and bark...... and wood particles treated with additive. A two-color technique with subtraction of the background light was used to estimate particle temperatures during experiments. A transmission-emission technique was used tomeasure the gas temperature in the reactor tube. Gas temperature measurements were in good...... agreement with thermocouple readings. Gas lines and bands from CO, CO2 and H2O can be observed in the spectra. CO was only observed at the first measuring port (100ms) with the strongest CO-signal seen during experiments with straw particles. Variations in gas concentration (CO2 and H2O) and the signal from...

  10. Estimating grass and grass silage degradation characteristics by in situ and in vitro gas production methods

    Directory of Open Access Journals (Sweden)

    Danijel Karolyi

    2010-01-01

    Full Text Available Fermentation characteristics of grass and grass silage at different maturities were studied using in situ and in vitro gas production methods. In situ data determined difference between grass and silage. Degradable fraction decreased as grass matured while the undegradable fraction increased. Rate of degradation (kd was slower for silage than fresh grass. Gas production method (GP data showed that fermentation of degradable fraction was different between stage of maturity in both grass and silage. Other data did not show any difference with the exception for the rate of GP of soluble and undegradable fraction. The in situ degradation characteristics were estimated from GP characteristics. The degradable and undegradable fractions could be estimated by multiple relationships. Using the three-phases model for gas production kd and fermentable organic matter could be estimated from the same parameters. The only in situ parameter that could not be estimated with GP parameters was the soluble fraction. The GP method and the three phases model provided to be an alternative to the in situ method for animal feed evaluations.

  11. Development of Nano-crystalline Doped-Ceramic Enabled Fiber Sensors for High Temperature In-Situ Monitoring of Fossil Fuel Gases

    Energy Technology Data Exchange (ETDEWEB)

    Xiao, Hai [Missouri Univ. of Science and Technology, Rolla, MO (United States); Dong, Junhang [Univ. of Cincinnati, OH (United States); Lin, Jerry [Arizona State Univ., Tempe, AZ (United States); Romero, Van [New Mexico Institute of Mining and Technology, Socorro, NM (United States)

    2012-03-01

    This is a final technical report for the first project year from July 1, 2005 to Jan 31, 2012 for DoE/NETL funded project DE-FC26-05NT42439: Development of Nanocrystalline Doped-Ceramic Enabled Fiber Sensors for High Temperature In-Situ Monitoring of Fossil Fuel Gases. This report summarizes the technical progresses and achievements towards the development of novel nanocrystalline doped ceramic material-enabled optical fiber sensors for in situ and real time monitoring the gas composition of flue or hot gas streams involved in fossil-fuel based power generation and hydrogen production.

  12. Temperature monitoring of gas-cooled reactors

    International Nuclear Information System (INIS)

    Kaiser, G.E.

    1977-01-01

    The present paper deals with questions like : a) Why temperature monitoring in high-temperature reactors at all. b) How are the measuring positions arranged and how are the measurements designed. c) What technique of temperature measurement is applied. (RW) [de

  13. Portable Mass Spectrometer Applications for In Situ Environmental Gas Monitoring

    Science.gov (United States)

    Griffin, Timothy P.; Diaz, J. Andres; Arkin, C. Richard; Conejo, Elian

    2005-01-01

    Primary Goal of this project is to (1) Design/build a flexible system to monitor air contamination (2) Learn requirements for operating system in low pressure and low temperature environments (3) Design/build system for integration into aircraft and automobiles Secondary Goals/Offshoots are (1) Fly aboard different aircraft (2)Hand-carry unit (3) Drive unit in automobiles.

  14. Apparatus using radioactive particles for measuring gas temperatures

    International Nuclear Information System (INIS)

    Compton, W.A.; Duffy, T.E.; Seegall, M.I.

    1975-01-01

    Apparatus for producing a signal indicative of the temperature of a heated gas is described comprising a beta particle source; a beta particle detector which intercepts particles emitted from said source; circuitry for converting the detector output to a signal indicative of the density of the gas; a pressure transducer for generating a signal indicative of the pressure on the gas; and circuitry for dividing the pressure signal by the density signal to produce a signal indicative of the average temperature of the gas along the path between the beta particle source and the beta particle detector. (auth)

  15. Novel silica membranes for high temperature gas separations

    KAUST Repository

    Bighane, Neha

    2011-04-01

    This article describes fabrication of novel silica membranes derived via controlled oxidative thermolysis of polydimethylsiloxane and their gas separation performance. The optimized protocol for fabrication of the silica membranes is described and pure gas separation performance in the temperature range 35-80°C is presented. It is observed that the membranes exhibit activated transport for small gas penetrants such as He, H 2 and CO 2. The membranes can withstand temperatures up to 350°C in air and may ultimately find use in H 2/CO 2 separations to improve efficiency in the water-gas shift reactor process. © 2011 Elsevier B.V.

  16. Method for high temperature mercury capture from gas streams

    Science.gov (United States)

    Granite, Evan J [Wexford, PA; Pennline, Henry W [Bethel Park, PA

    2006-04-25

    A process to facilitate mercury extraction from high temperature flue/fuel gas via the use of metal sorbents which capture mercury at ambient and high temperatures. The spent sorbents can be regenerated after exposure to mercury. The metal sorbents can be used as pure metals (or combinations of metals) or dispersed on an inert support to increase surface area per gram of metal sorbent. Iridium and ruthenium are effective for mercury removal from flue and smelter gases. Palladium and platinum are effective for mercury removal from fuel gas (syngas). An iridium-platinum alloy is suitable for metal capture in many industrial effluent gas streams including highly corrosive gas streams.

  17. Direct gas-solid carbonation kinetics of steel slag and the contribution to in situ sequestration of flue gas CO(2) in steel-making plants.

    Science.gov (United States)

    Tian, Sicong; Jiang, Jianguo; Chen, Xuejing; Yan, Feng; Li, Kaimin

    2013-12-01

    Direct gas-solid carbonation of steel slag under various operational conditions was investigated to determine the sequestration of the flue gas CO2 . X-ray diffraction analysis of steel slag revealed the existence of portlandite, which provided a maximum theoretical CO2 sequestration potential of 159.4 kg CO 2 tslag (-1) as calculated by the reference intensity ratio method. The carbonation reaction occurred through a fast kinetically controlled stage with an activation energy of 21.29 kJ mol(-1) , followed by 10(3) orders of magnitude slower diffusion-controlled stage with an activation energy of 49.54 kJ mol(-1) , which could be represented by a first-order reaction kinetic equation and the Ginstling equation, respectively. Temperature, CO2 concentration, and the presence of SO2 impacted on the carbonation conversion of steel slag through their direct and definite influence on the rate constants. Temperature was the most important factor influencing the direct gas-solid carbonation of steel slag in terms of both the carbonation conversion and reaction rate. CO2 concentration had a definite influence on the carbonation rate during the kinetically controlled stage, and the presence of SO2 at typical flue gas concentrations enhanced the direct gas-solid carbonation of steel slag. Carbonation conversions between 49.5 % and 55.5 % were achieved in a typical flue gas at 600 °C, with the maximum CO2 sequestration amount generating 88.5 kg CO 2 tslag (-1) . Direct gas-solid carbonation of steel slag showed a rapid CO2 sequestration rate, high CO2 sequestration amounts, low raw-material costs, and a large potential for waste heat utilization, which is promising for in situ carbon capture and sequestration in the steel industry. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  18. Two stage, low temperature, catalyzed fluidized bed incineration with in situ neutralization for radioactive mixed wastes

    International Nuclear Information System (INIS)

    Wade, J.F.; Williams, P.M.

    1995-01-01

    A two stage, low temperature, catalyzed fluidized bed incineration process is proving successful at incinerating hazardous wastes containing nuclear material. The process operates at 550 degrees C and 650 degrees C in its two stages. Acid gas neutralization takes place in situ using sodium carbonate as a sorbent in the first stage bed. The feed material to the incinerator is hazardous waste-as defined by the Resource Conservation and Recovery Act-mixed with radioactive materials. The radioactive materials are plutonium, uranium, and americium that are byproducts of nuclear weapons production. Despite its low temperature operation, this system successfully destroyed poly-chlorinated biphenyls at a 99.99992% destruction and removal efficiency. Radionuclides and volatile heavy metals leave the fluidized beds and enter the air pollution control system in minimal amounts. Recently collected modeling and experimental data show the process minimizes dioxin and furan production. The report also discusses air pollution, ash solidification, and other data collected from pilot- and demonstration-scale testing. The testing took place at Rocky Flats Environmental Technology Site, a US Department of Energy facility, in the 1970s, 1980s, and 1990s

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

    Science.gov (United States)

    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

  20. A new algorithm predicts pressure and temperature profiles of gas/gas-condensate transmission pipelines

    Energy Technology Data Exchange (ETDEWEB)

    Mokhatab, Saied [OIEC - Oil Industries' Engineering and Construction Group, Tehran (Iran, Islamic Republic of); Vatani, Ali [University of Tehran (Iran, Islamic Republic of)

    2003-07-01

    The main objective of the present study has been the development of a relatively simple analytical algorithm for predicting flow temperature and pressure profiles along the two-phase, gas/gas-condensate transmission pipelines. Results demonstrate the ability of the method to predict reasonably accurate pressure gradient and temperature gradient profiles under operating conditions. (author)

  1. Gas temperature of capacitance spark discharge in air

    International Nuclear Information System (INIS)

    Ono, Ryo; Nifuku, Masaharu; Fujiwara, Shuzo; Horiguchi, Sadashige; Oda, Tetsuji

    2005-01-01

    Capacitance spark discharge has been widely used for studying the ignition of flammable gas caused by electrostatic discharge. In the present study, the gas temperature of capacitance spark discharge is measured. The gas temperature is an important factor in understanding the electrostatic ignition process because it influences the reaction rate of ignition. Spark discharge is generated in air with a pulse duration shorter than 100 ns. The discharge energy is set to 0.03-1 mJ. The rotational and vibrational temperatures of the N 2 molecule are measured using the emission spectrum of the N 2 second positive system. The rotational and vibrational temperatures are estimated to be 500 and 5000 K, respectively, which are independent of the discharge energy. This result indicates that most of the electron energy is consumed in the excitation of vibrational levels of molecules rather than the heating of the gas. The gas temperature after discharge is also measured by laser-induced fluorescence of OH radicals. It is shown that the gas temperature increases after discharge and reaches approximately 1000 K at 3 μs after discharge. Then the temperature decreases at a rate in the range of 8-35 K/μs depending on the discharge energy

  2. In situ water and gas injection experiments performed in the Hades Underground Research Facility

    Energy Technology Data Exchange (ETDEWEB)

    Volckaert, G.; Ortiz, L.; Put, M. [SCK-CEN, Mol (Belgium). Geological Waste Disposal Unit

    1995-12-31

    The movement of water and gas through plastic clay is an important subject in the research at SCK-CEN on the possible disposal of high level radioactive waste in the Boom clay layer at Mol. Since the construction of the Hades underground research facility in 1983, SCK-CEN has developed and installed numerous piezometers for the geohydrologic characterization and for in situ radionuclide migration experiments. In situ gas and water injection experiments have been performed at two different locations in the underground laboratory. The first location is a multi filter piezometer installed vertically at the bottom of the shaft in 1986. The second location is a three dimensional configuration of four horizontal multi piezometers installed from the gallery. This piezometer configuration was designed for the MEGAS (Modelling and Experiments on GAS migration through argillaceous rocks) project and installed in 1992. It contains 29 filters at distances between 10 m and 15 m from the gallery in the clay. Gas injection experiments show that gas breakthrough occurs at a gas overpressure of about 0.6 MPa. The breakthrough occurs by the creation of gas pathways along the direction of lowest resistance i.e. the zone of low effective stress resulting from the drilling of the borehole. The water injections performed in a filter -- not used for gas injection -- show that the flow of water is also influenced by the mechanical stress conditions. Low effective stress leads to higher hydraulic conductivity. However, water overpressures up to 1.3 MPa did not cause hydrofracturing. Water injections performed in a filter previously used for gas injections, show that the occluded gas hinders the water flow and reduces the hydraulic conductivity by a factor two.

  3. Evaluation of gas migration characteristics of compacted bentonite considering in-situ conditions of disposal facility

    International Nuclear Information System (INIS)

    Tanaka, Yukihisa; Hironaga, Michihiko

    2012-01-01

    In the current concept of repository for radioactive waste disposal, compacted bentonite will be used as an engineered barrier mainly for inhibiting migration of radioactive nuclides. Hydrogen gas can be generated inside the engineered barrier by anaerobic corrosion of metals used for containers, etc. If the gas generation rate exceeds the diffusion rate of gas molecules inside of the engineered barrier, gas will accumulate in the void space inside of the engineered barrier until its pressure becomes large enough for it to enter the bentonite as a discrete gaseous phase. It is expected to be not easy for gas to entering into the bentonite as a discrete gaseous phase because the pore of compacted bentonite is so minute. Therefore it is necessary to investigate the effect of gas pressure generation and gas migration on the engineered barrier, peripheral facilities and ground. CRIEPI already proposed an analytical method for simulating gas migration through the compacted bentonite using the model of two phase flow through deformable porous media. Though validity of the analytical code of CRIEPI was examined by comparing existing gas migration test results with the calculated results, further validation is needed because in situ conditions, such as stress conditions and boundary condition, are different from conventional laboratory gas migration tent. In this study, gas migration tests whose initial axial stress is larger than initial radial stress and gas migration tests whose gas inlet is small. Simulation of the test results is also conducted. Comparing the test results with the calculated results, it is revealed that the analytical code of CRIEPI can simulate gas migration behavior through compacted bentonite with accuracy. (author)

  4. Fuel arrangement for high temperature gas cooled reactor

    International Nuclear Information System (INIS)

    Tobin, J.M.

    1978-01-01

    Disclosed is a fuel arrangement for a high temperature gas cooled reactor including fuel assemblies with separate directly cooled fissile and fertile fuel elements removably inserted in an elongated moderator block also having a passageway for control elements

  5. Quantitative Analysis of Oxygen Gas Exhausted from Anode through In Situ Measurement during Electrolytic Reduction

    Directory of Open Access Journals (Sweden)

    Eun-Young Choi

    2017-01-01

    Full Text Available Quantitative analysis by in situ measurement of oxygen gas evolved from an anode was employed to monitor the progress of electrolytic reduction of simulated oxide fuel in a molten Li2O–LiCl salt. The electrolytic reduction of 0.6 kg of simulated oxide fuel was performed in 5 kg of 1.5 wt.% Li2O–LiCl molten salt at 650°C. Porous cylindrical pellets of simulated oxide fuel were used as the cathode by loading a stainless steel wire mesh cathode basket. A platinum plate was employed as the anode. The oxygen gas evolved from the anode was exhausted to the instrumentation for in situ measurement during electrolytic reduction. The instrumentation consisted of a mass flow controller, pump, wet gas meter, and oxygen gas sensor. The oxygen gas was successfully measured using the instrumentation in real time. The measured volume of the oxygen gas was comparable to the theoretically calculated volume generated by the charge applied to the simulated oxide fuel.

  6. The temperature distribution in a gas core fission reactor

    Energy Technology Data Exchange (ETDEWEB)

    Hoogenboom, J.E.; Dam, H. van; Kuijper, J.C. (Interuniversitair Reactor Inst., Delft (Netherlands)); Kistemaker, J.; Boersma-Klein, W.; Vitalis, F. (FOM-Instituut voor Atoom-en Molecuulfysica, Amsterdam (Netherlands))

    1991-01-01

    A model is proposed for the heat transport in a nuclear reactor with gaseous fuel at high temperatures taking into account radiative and kinetic heat transfer. A derivation is given of the equation determining the temperature distribution in a gas core reactor and different numerical solution methods are discussed in detail. Results are presented of the temperature distribution. The influence of the kinetic heat transport and of dissociation of the gas molecules is shown. Also discussed is the importance of the temperature gradient at the reactor wall and its dependence on system parameters. (author).

  7. The temperature distribution in a gas core fission reactor

    International Nuclear Information System (INIS)

    Hoogenboom, J.E.; Dam, H. van; Kuijper, J.C.; Kistemaker, J.; Boersma-Klein, W.; Vitalis, F.

    1991-01-01

    A model is proposed for the heat transport in a nuclear reactor with gaseous fuel at high temperatures taking into account radiative and kinetic heat transfer. A derivation is given of the equation determining the temperature distribution in a gas core reactor and different numerical solution methods are discussed in detail. Results are presented of the temperature distribution. The influence of the kinetic heat transport and of dissociation of the gas molecules is shown. Also discussed is the importance of the temperature gradient at the reactor wall and its dependence on system parameters. (author)

  8. Analysis and improvement of gas turbine blade temperature measurement error

    International Nuclear Information System (INIS)

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

    2015-01-01

    Gas turbine blade components are easily damaged; they also operate in harsh high-temperature, high-pressure environments over extended durations. Therefore, ensuring that the blade temperature remains within the design limits is very important. In this study, measurement errors in turbine blade temperatures were analyzed, taking into account detector lens contamination, the reflection of environmental energy from the target surface, the effects of the combustion gas, and the emissivity of the blade surface. In this paper, each of the above sources of measurement error is discussed, and an iterative computing method for calculating blade temperature is proposed. (paper)

  9. Analysis and improvement of gas turbine blade temperature measurement error

    Science.gov (United States)

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

    2015-10-01

    Gas turbine blade components are easily damaged; they also operate in harsh high-temperature, high-pressure environments over extended durations. Therefore, ensuring that the blade temperature remains within the design limits is very important. In this study, measurement errors in turbine blade temperatures were analyzed, taking into account detector lens contamination, the reflection of environmental energy from the target surface, the effects of the combustion gas, and the emissivity of the blade surface. In this paper, each of the above sources of measurement error is discussed, and an iterative computing method for calculating blade temperature is proposed.

  10. Fast temperature programming in gas chromatography using resistive heating

    NARCIS (Netherlands)

    Dallüge, J.; Ou-Aissa, R.; Vreuls, J.J.; Brinkman, U.A.T.; Veraart, J.R.

    1999-01-01

    The features of a resistive-heated capillary column for fast temperature-programmed gas chromatography (GC) have been evaluated. Experiments were carried out using a commercial available EZ Flash GC, an assembly which can be used to upgrade existing gas chromatographs. The capillary column is placed

  11. In situ X-ray ptychography imaging of high-temperature CO2 acceptor particle agglomerates

    DEFF Research Database (Denmark)

    Høydalsvik, Kristin; Fløystad, Jostein Bø; Zhao, Tiejun

    2014-01-01

    be used for in situ phase contrast imaging in structure studies at atmospheric pressure and elevated temperatures. Lithium zirconate, a candidate CO2 capture material, was studied at a pressure of one atmosphere in air and in CO2, at temperatures exceeding 600 °C. Images with a spatial resolution better...

  12. Planning of in-situ experiment for understanding of gas migration behaviour in sedimentary rock. (1) Setting of gas injection procedure

    International Nuclear Information System (INIS)

    Tanai, Kenji; Fujita, Tomoo; Noda, Masaru; Yamamoto, Shuichi; Shimura, Tomoyuki; Sato, Shin

    2013-01-01

    Japan Atomic Energy Agency has been planning in-situ gas migration test in Horonobe URL, Hokkaido. This paper discusses the optimum gas injection procedure for the test to understand gas migration behaviour in surrounded rock. The stepwise constant gas injection was selected, taking into account domestic and overseas gas related research results. Hydro-mechanical-gas coupling analysis which is able to consider the dissolved methane in Horonobe groundwater was applied to evaluate the gas behaviour. The results have indicated no significant mechanical damages to the rock and have supported the appropriateness of selected gas injection procedure for the test. (author)

  13. Temperature dependence of the in situ widths of a rotating condensate in one dimensional optical potential

    International Nuclear Information System (INIS)

    Hassan, Ahmed S.; Soliman, Shemi S.M.

    2016-01-01

    In this paper, a conventional method of quantum statistical mechanics is used to study the temperature dependence of the in situ widths of a rotating condensate bosons in 1D optical potential. We trace the experimentally accessible parameters for which the temperature dependence of the in situ widths becomes perceivable. The calculated results showed that the temperature dependence of the in situ widths is completely different from that of a rotating condensate or trapped bosons in the optical lattice separately. The z-width shows distinct behavior from x- and y-widths due to the rotation effect. The obtained results provide useful qualitative theoretical results for future Bose Einstein condensation experiments in such traps. - Highlights: • The temperature dependence of the in situ widths of a rotating condensate boson in 1D optical potential is investigated. • We trace the experimentally accessible parameters for which the in situ widths become perceivable. • The above mentioned parameters exhibit a characteristic rotation rate and optical potential depth dependence. • Characteristic dependence of the effective widths on temperature is investigated. • Our results provide useful qualitatively and quantitative theoretical results for experiments in various traps.

  14. Development history of the gas turbine modular high temperature reactor

    International Nuclear Information System (INIS)

    Brey, H.L.

    2001-01-01

    The development of the high temperature gas cooled reactor (HTGR) as an environmentally agreeable and efficient power source to support the generation of electricity and achieve a broad range of high temperature industrial applications has been an evolutionary process spanning over four decades. This process has included ongoing major development in both the HTGR as a nuclear energy source and associated power conversion systems from the steam cycle to the gas turbine. This paper follows the development process progressively through individual plant designs from early research of the 1950s to the present focus on the gas turbine modular HTGR. (author)

  15. Reduction and Analysis of Low Temperature Shift Heterogeneous Catalyst for Water Gas Reaction in Ammonia Production

    Directory of Open Access Journals (Sweden)

    Zečević, N.

    2013-09-01

    Full Text Available In order to obtain additional quantities of hydrogen after the reforming reactions of natural gas and protect the ammonia synthesis catalyst, it is crucial to achieve and maintain maximum possible activity, selectivity and stability of the low temperature shift catalyst for conversion of water gas reaction during its lifetime. Whereas the heterogeneous catalyst comes in oxidized form, it is of the utmost importance to conduct the reduction procedure properly. The proper reduction procedure and continuous analysis of its performance would ensure the required activity, selectivity and stability throughout the catalyst’s service time. For the proper reduction procedure ofthe low temperature shift catalyst, in addition to process equipment, also necessary is a reliable and realistic system for temperature measurements, which will be effective for monitoring the exothermal temperature curves through all catalyst bed layers. For efficiency evaluation of low shift temperature catalyst reduction and its optimization, it is necessary to determine at regular time intervals the temperature approach to equilibrium and temperature profiles of individual layers by means of "S" and "die off" temperature exothermal curves. Based on the obtained data, the optimum inlet temperature could be determined, in order to maximally extend the service life of the heterogeneous catalyst as much as possible, and achieve the optimum equilibrium for conversion of the water gas. This paper presents the methodology for in situ reduction of the low temperature shift heterogeneous catalyst and the developed system for monitoring its individual layers to achieve the minimum possible content of carbon monoxide at the exit of the reactor. The developed system for temperature monitoring through heterogeneous catalyst layers provides the proper procedure for reduction and adjustment of optimum process working conditions for the catalyst by the continuous increase of reactor inlet

  16. Arctic surface temperatures from Metop AVHRR compared to in situ ocean and land data

    Directory of Open Access Journals (Sweden)

    G. Dybkjær

    2012-11-01

    Full Text Available The ice surface temperature (IST is an important boundary condition for both atmospheric and ocean and sea ice models and for coupled systems. An operational ice surface temperature product using satellite Metop AVHRR infra-red data was developed for MyOcean. The IST can be mapped in clear sky regions using a split window algorithm specially tuned for sea ice. Clear sky conditions prevail during spring in the Arctic, while persistent cloud cover limits data coverage during summer. The cloud covered regions are detected using the EUMETSAT cloud mask. The Metop IST compares to 2 m temperature at the Greenland ice cap Summit within STD error of 3.14 °C and to Arctic drifting buoy temperature data within STD error of 3.69 °C. A case study reveals that the in situ radiometer data versus satellite IST STD error can be much lower (0.73 °C and that the different in situ measurements complicate the validation. Differences and variability between Metop IST and in situ data are analysed and discussed. An inter-comparison of Metop IST, numerical weather prediction temperatures and in situ observation indicates large biases between the different quantities. Because of the scarcity of conventional surface temperature or surface air temperature data in the Arctic, the satellite IST data with its relatively good coverage can potentially add valuable information to model analysis for the Arctic atmosphere.

  17. Method for increasing the calorific value of gas produced by the in situ combustion of coal

    Science.gov (United States)

    Shuck, Lowell Z.

    1978-01-01

    The present invention relates to the production of relatively high Btu gas by the in situ combustion of subterranean coal. The coal bed is penetrated with a horizontally-extending borehole and combustion is initiated in the coal bed contiguous to the borehole. The absolute pressure within the resulting combustion zone is then regulated at a desired value near the pore pressure within the coal bed so that selected quantities of water naturally present in the coal will flow into the combustion zone to effect a hydrogen and carbon monoxide-producing steam-carbon reaction with the hot carbon in the combustion zone for increasing the calorific value of the product gas.

  18. In situ temperature tunable pores of shape memory polyurethane membranes

    International Nuclear Information System (INIS)

    Ahn, Joon-Sung; Yu, Woong-Ryeol; Youk, Ji Ho; Ryu, Hee Youk

    2011-01-01

    Conventional shape memory polymers, such as shape memory polyurethanes (SMPU), can exhibit net two-way shape memory behavior (2WSM), i.e., upon heating and subsequent cooling, their macroscopic shapes change reversibly under an applied bias load. This paper is aimed at reporting similar 2WSM behavior, especially by focusing on the size of nanopores/micropores in SMPU membranes, i.e., the size of the pores can be reversibly changed by up to about 300 nm upon repeated heating and cooling. The SMPU membranes were prepared by electrospinning and elongated at temperatures higher than the transition temperature of the SMPU. Under the constant stress, the size change of the pores in the membranes was measured by applying cyclic temperature change. It was observed that the pore size changed from 150 to 440 nm according to the temperature change, demonstrating that the SMPU membrane can be utilized as a smart membrane to selectively separate substances according to their sizes by just controlling temperature

  19. A Smart Gas Sensor Insensitive to Humidity and Temperature Variations

    International Nuclear Information System (INIS)

    Hajmirzaheydarali, Mohammadreza; Ghafarinia, Vahid

    2011-01-01

    The accuracy of the quantitative sensing of volatile organic compounds by chemoresistive gas sensors suffers from the fluctuations in the background atmospheric conditions. This is caused by the drift-like terms introduced in the responses by these instabilities, which should be identified and compensated. Here, a mathematical model is presented for a specific chemoresistive gas sensor, which facilitates these identification and compensation processes. The resistive gas sensor was considered as a multi-input-single-output system. Along with the steady state value of the measured sensor resistance, the ambient humidity and temperature are the inputs to the system, while the concentration level of the target gas is the output. The parameters of the model were calculated based on the experimental database. The model was simulated by the utilization of an artificial neural network. This was connected to the sensor and could deliver the correct contamination level upon receiving the measured gas response, ambient humidity and temperature.

  20. In-situ high temperature irradiation setup for temperature dependent structural studies of materials under swift heavy ion irradiation

    International Nuclear Information System (INIS)

    Kulriya, P.K.; Kumari, Renu; Kumar, Rajesh; Grover, V.; Shukla, R.; Tyagi, A.K.; Avasthi, D.K.

    2015-01-01

    An in-situ high temperature (1000 K) setup is designed and installed in the materials science beam line of superconducting linear accelerator at the Inter-University Accelerator Centre (IUAC) for temperature dependent ion irradiation studies on the materials exposed with swift heavy ion (SHI) irradiation. The Gd 2 Ti 2 O 7 pyrochlore is irradiated using 120 MeV Au ion at 1000 K using the high temperature irradiation facility and characterized by ex-situ X-ray diffraction (XRD). Another set of Gd 2 Ti 2 O 7 samples are irradiated with the same ion beam parameter at 300 K and simultaneously characterized using in-situ XRD available in same beam line. The XRD studies along with the Raman spectroscopic investigations reveal that the structural modification induced by the ion irradiation is strongly dependent on the temperature of the sample. The Gd 2 Ti 2 O 7 is readily amorphized at an ion fluence 6 × 10 12 ions/cm 2 on irradiation at 300 K, whereas it is transformed to a radiation-resistant anion-deficient fluorite structure on high temperature irradiation, that amorphized at ion fluence higher than 1 × 10 13 ions/cm 2 . The temperature dependent ion irradiation studies showed that the ion fluence required to cause amorphization at 1000 K irradiation is significantly higher than that required at room temperature irradiation. In addition to testing the efficiency of the in-situ high temperature irradiation facility, the present study establishes that the radiation stability of the pyrochlore is enhanced at higher temperatures

  1. Modern gas-based temperature and pressure measurements

    CERN Document Server

    Pavese, Franco

    2013-01-01

    This 2nd edition volume of Modern Gas-Based Temperature and Pressure Measurements follows the first publication in 1992. It collects a much larger set of information, reference data, and bibliography in temperature and pressure metrology of gaseous substances, including the physical-chemical issues related to gaseous substances. The book provides solutions to practical applications where gases are used in different thermodynamic conditions. Modern Gas-Based Temperature and Pressure Measurements, 2nd edition is the only comprehensive survey of methods for pressure measurement in gaseous media used in the medium-to-low pressure range closely connected with thermometry. It assembles current information on thermometry and manometry that involve the use of gaseous substances which are likely to be valid methods for the future. As such, it is an important resource for the researcher. This edition is updated through the very latest scientific and technical developments of gas-based temperature and pressure measurem...

  2. Measuring gas temperature during spin-exchange optical pumping process

    Science.gov (United States)

    Normand, E.; Jiang, C. Y.; Brown, D. R.; Robertson, L.; Crow, L.; Tong, X.

    2016-04-01

    The gas temperature inside a Spin-Exchange Optical Pumping (SEOP) laser-pumping polarized 3He cell has long been a mystery. Different experimental methods were employed to measure this temperature but all were based on either modelling or indirect measurement. To date there has not been any direct experimental measurement of this quantity. Here we present the first direct measurement using neutron transmission to accurately determine the number density of 3He, the temperature is obtained using the ideal gas law. Our result showed a surprisingly high gas temperature of 380°C, compared to the 245°C of the 3He cell wall temperature and 178°C of the optical pumping oven temperature. This experiment result may be used to further investigate the unsolved puzzle of the "X-factor" in the SEOP process which places an upper bound to the 3He polarization that can be achieved. Additional spin relaxation mechanisms might exist due to the high gas temperature, which could explain the origin of the X-factor.

  3. Design and development of gas turbine high temperature reactor 300

    International Nuclear Information System (INIS)

    Kunitomi, Kazuhiko; Katanishi, Shoji; Takada, Shoji; Yan, Xing; Takizuka, Takakazu

    2003-01-01

    JAERI (Japan Atomic Energy Research Institute) has been designing a Japan's original gas turbine high temperature reactor, GTHTR300 (Gas Turbine High Temperature Reactor 300). The greatly simplified design based on salient features of the HTGR (High Temperature Gas-cooled reactor) with a closed helium gas turbine enables the GTHTR300 a high efficient and economically competitive reactor to be deployed in early 2010s. Also, the GTHTR300 fully taking advantage of various experiences accumulated in design, construction and operation of the HTTR (High Temperature Engineering Test Reactor) and fossil gas turbine systems reduces technological development concerning a reactor system and electric generation system. Original features of this system are core design with two-year refueling interval, conventional steel material usage for a reactor pressure vessel, innovative plant flow scheme and horizontally installed gas turbine unit. Due to these salient features, the capital cost of the GTHTR300 is less than a target cost of 200 thousands Yen/kWe, and the electric generation cost is close to a target cost of 4 Yen/kWh. This paper describes the original design features focusing on reactor core design, fuel design, in-core structure design and reactor pressure vessel design except PCU design. Also, R and D for developing the power conversion unit is briefly described. The present study is entrusted from the Ministry of Education, Culture, Sports, Science and Technology of Japan. (author)

  4. Stakeholder acceptance analysis: In-well vapor stripping, in-situ bioremediation, gas membrane separation system (membrane separation)

    International Nuclear Information System (INIS)

    Peterson, T.

    1995-12-01

    This document provides stakeholder evaluations on innovative technologies to be used in the remediation of volatile organic compounds from soils and ground water. The technologies evaluated are; in-well vapor stripping, in-situ bioremediation, and gas membrane separation

  5. Stream temperature estimated in situ from thermal-infrared images: best estimate and uncertainty

    International Nuclear Information System (INIS)

    Iezzi, F; Todisco, M T

    2015-01-01

    The paper aims to show a technique to estimate in situ the stream temperature from thermal-infrared images deepening its best estimate and uncertainty. Stream temperature is an important indicator of water quality and nowadays its assessment is important particularly for thermal pollution monitoring in water bodies. Stream temperature changes are especially due to the anthropogenic heat input from urban wastewater and from water used as a coolant by power plants and industrial manufacturers. The stream temperatures assessment using ordinary techniques (e.g. appropriate thermometers) is limited by sparse sampling in space due to a spatial discretization necessarily punctual. Latest and most advanced techniques assess the stream temperature using thermal-infrared remote sensing based on thermal imagers placed usually on aircrafts or using satellite images. These techniques assess only the surface water temperature and they are suitable to detect the temperature of vast water bodies but do not allow a detailed and precise surface water temperature assessment in limited areas of the water body. The technique shown in this research is based on the assessment of thermal-infrared images obtained in situ via portable thermal imager. As in all thermographic techniques, also in this technique, it is possible to estimate only the surface water temperature. A stream with the presence of a discharge of urban wastewater is proposed as case study to validate the technique and to show its application limits. Since the technique analyzes limited areas in extension of the water body, it allows a detailed and precise assessment of the water temperature. In general, the punctual and average stream temperatures are respectively uncorrected and corrected. An appropriate statistical method that minimizes the errors in the average stream temperature is proposed. The correct measurement of this temperature through the assessment of thermal- infrared images obtained in situ via portable

  6. Determination of gas temperature in the plasmatron channel according to the known distribution of electronic temperature

    Directory of Open Access Journals (Sweden)

    Gerasimov Alexander V.

    2013-01-01

    Full Text Available An analytical method to calculate the temperature distribution of heavy particles in the channel of the plasma torch on the known distribution of the electronic temperature has been proposed. The results can be useful for a number of model calculations in determining the most effective conditions of gas blowing through the plasma torch with the purpose of heating the heavy component. This approach allows us to understand full details about the heating of cold gas, inpouring the plasma, and to estimate correctly the distribution of the gas temperature inside the channel.

  7. Multi-spectral temperature measurement method for gas turbine blade

    Science.gov (United States)

    Gao, Shan; Feng, Chi; Wang, Lixin; Li, Dong

    2016-02-01

    One of the basic methods to improve both the thermal efficiency and power output of a gas turbine is to increase the firing temperature. However, gas turbine blades are easily damaged in harsh high-temperature and high-pressure environments. Therefore, ensuring that the blade temperature remains within the design limits is very important. There are unsolved problems in blade temperature measurement, relating to the emissivity of the blade surface, influences of the combustion gases, and reflections of radiant energy from the surroundings. In this study, the emissivity of blade surfaces has been measured, with errors reduced by a fitting method, influences of the combustion gases have been calculated for different operational conditions, and a reflection model has been built. An iterative computing method is proposed for calculating blade temperatures, and the experimental results show that this method has high precision.

  8. High temperature gas dynamics an introduction for physicists and engineers

    CERN Document Server

    Bose, Tarit K

    2014-01-01

    High Temperature Gas Dynamics is a primer for scientists, engineers, and students who would like to have a basic understanding of the physics and the behavior of high-temperature gases. It is a valuable tool for astrophysicists as well. The first chapters treat the basic principles of quantum and statistical mechanics and how to derive thermophysical properties from them. Special topics are included that are rarely found in other textbooks, such as the thermophysical and transport properties of multi-temperature gases and a novel method to compute radiative transfer. Furthermore, collision processes between different particles are discussed. Separate chapters deal with the production of high-temperature gases and with electrical emission in plasmas, as well as related diagnostic techniques.This new edition adds over 100 pages and includes the following updates: several sections on radiative properties of high temperature gases and various radiation models, a section on shocks in magneto-gas-dynamics, a sectio...

  9. Gravitational collapse of a magnetized fermion gas with finite temperature

    Energy Technology Data Exchange (ETDEWEB)

    Delgado Gaspar, I. [Instituto de Geofisica y Astronomia (IGA), La Habana (Cuba); Perez Martinez, A. [Instituto de Cibernetica, Matematica y Fisica (ICIMAF), La Habana (Cuba); Sussman, Roberto A. [Instituto de Ciencias Nucleares, Universidad Nacional Autonoma de Mexico (ICN-UNAM), Mexico (Mexico); Ulacia Rey, A. [Instituto de Cibernetica, Matematica y Fisica (ICIMAF), La Habana (Cuba); Instituto de Ciencias Nucleares, Universidad Nacional Autonoma de Mexico (ICN-UNAM), Mexico (Mexico)

    2013-07-15

    We examine the dynamics of a self-gravitating magnetized fermion gas at finite temperature near the collapsing singularity of a Bianchi-I spacetime. Considering a general set of appropriate and physically motivated initial conditions, we transform Einstein-Maxwell field equations into a complete and self-consistent dynamical system amenable for numerical work. The resulting numerical solutions reveal the gas collapsing into both, isotropic (''point-like'') and anisotropic (''cigar-like''), singularities, depending on the initial intensity of the magnetic field. We provide a thorough study of the near collapse behavior and interplay of all relevant state and kinematic variables: temperature, expansion scalar, shear scalar, magnetic field, magnetization, and energy density. A significant qualitative difference in the behavior of the gas emerges in the temperature range T/m{sub f} {proportional_to} 10{sup -6} and T/m{sub f} {proportional_to} 10{sup -3}. (orig.)

  10. Combining Remote Temperature Sensing with in-Situ Sensing to Track Marine/Freshwater Mixing Dynamics

    Directory of Open Access Journals (Sweden)

    Margaret McCaul

    2016-08-01

    Full Text Available The ability to track the dynamics of processes in natural water bodies on a global scale, and at a resolution that enables highly localised behaviour to be visualized, is an ideal scenario for understanding how local events can influence the global environment. While advances in in-situ chem/bio-sensing continue to be reported, costs and reliability issues still inhibit the implementation of large-scale deployments. In contrast, physical parameters like surface temperature can be tracked on a global scale using satellite remote sensing, and locally at high resolution via flyovers and drones using multi-spectral imaging. In this study, we show how a much more complete picture of submarine and intertidal groundwater discharge patterns in Kinvara Bay, Galway can be achieved using a fusion of data collected from the Earth Observation satellite (Landsat 8, small aircraft and in-situ sensors. Over the course of the four-day field campaign, over 65,000 in-situ temperatures, salinity and nutrient measurements were collected in parallel with high-resolution thermal imaging from aircraft flyovers. The processed in-situ data show highly correlated patterns between temperature and salinity at the southern end of the bay where freshwater springs can be identified at low tide. Salinity values range from 1 to 2 ppt at the southern end of the bay to 30 ppt at the mouth of the bay, indicating the presence of a freshwater wedge. The data clearly show that temperature differences can be used to track the dynamics of freshwater and seawater mixing in the inner bay region. This outcome suggests that combining the tremendous spatial density and wide geographical reach of remote temperature sensing (using drones, flyovers and satellites with ground-truthing via appropriately located in-situ sensors (temperature, salinity, chemical, and biological can produce a much more complete and accurate picture of the water dynamics than each modality used in isolation.

  11. Combining Remote Temperature Sensing with in-Situ Sensing to Track Marine/Freshwater Mixing Dynamics.

    Science.gov (United States)

    McCaul, Margaret; Barland, Jack; Cleary, John; Cahalane, Conor; McCarthy, Tim; Diamond, Dermot

    2016-08-31

    The ability to track the dynamics of processes in natural water bodies on a global scale, and at a resolution that enables highly localised behaviour to be visualized, is an ideal scenario for understanding how local events can influence the global environment. While advances in in-situ chem/bio-sensing continue to be reported, costs and reliability issues still inhibit the implementation of large-scale deployments. In contrast, physical parameters like surface temperature can be tracked on a global scale using satellite remote sensing, and locally at high resolution via flyovers and drones using multi-spectral imaging. In this study, we show how a much more complete picture of submarine and intertidal groundwater discharge patterns in Kinvara Bay, Galway can be achieved using a fusion of data collected from the Earth Observation satellite (Landsat 8), small aircraft and in-situ sensors. Over the course of the four-day field campaign, over 65,000 in-situ temperatures, salinity and nutrient measurements were collected in parallel with high-resolution thermal imaging from aircraft flyovers. The processed in-situ data show highly correlated patterns between temperature and salinity at the southern end of the bay where freshwater springs can be identified at low tide. Salinity values range from 1 to 2 ppt at the southern end of the bay to 30 ppt at the mouth of the bay, indicating the presence of a freshwater wedge. The data clearly show that temperature differences can be used to track the dynamics of freshwater and seawater mixing in the inner bay region. This outcome suggests that combining the tremendous spatial density and wide geographical reach of remote temperature sensing (using drones, flyovers and satellites) with ground-truthing via appropriately located in-situ sensors (temperature, salinity, chemical, and biological) can produce a much more complete and accurate picture of the water dynamics than each modality used in isolation.

  12. Ratiometric Afterglow Nanothermometer for Simultaneous in Situ Bioimaging and Local Tissue Temperature Sensing

    NARCIS (Netherlands)

    Yang, J.; Liu, Y.; Zhao, Y.; Gong, Z.; Zhang, M.; Yan, D.; Zhu, H.; Liu, C.; Xu, C.; Zhang, H.

    2017-01-01

    Simultaneous in situ bioimage tracing and temperature sensing have been two of the foci of modern biomedicine that have given birth to designing novel luminescent nanothermometers with dual functions. To minimize the disadvantages of existing approaches, like the surface effect of nanoparticles,

  13. In situ spectroscopy and spectroelectrochemistry of uranium in high-temperature alkali chloride molten salts.

    Science.gov (United States)

    Polovov, Ilya B; Volkovich, Vladimir A; Charnock, John M; Kralj, Brett; Lewin, Robert G; Kinoshita, Hajime; May, Iain; Sharrad, Clint A

    2008-09-01

    Soluble uranium chloride species, in the oxidation states of III+, IV+, V+, and VI+, have been chemically generated in high-temperature alkali chloride melts. These reactions were monitored by in situ electronic absorption spectroscopy. In situ X-ray absorption spectroscopy of uranium(VI) in a molten LiCl-KCl eutectic was used to determine the immediate coordination environment about the uranium. The dominant species in the melt was [UO 2Cl 4] (2-). Further analysis of the extended X-ray absorption fine structure data and Raman spectroscopy of the melts quenched back to room temperature indicated the possibility of ordering beyond the first coordination sphere of [UO 2Cl 4] (2-). The electrolytic generation of uranium(III) in a molten LiCl-KCl eutectic was also investigated. Anodic dissolution of uranium metal was found to be more efficient at producing uranium(III) in high-temperature melts than the cathodic reduction of uranium(IV). These high-temperature electrolytic processes were studied by in situ electronic absorption spectroelectrochemistry, and we have also developed in situ X-ray absorption spectroelectrochemistry techniques to probe both the uranium oxidation state and the uranium coordination environment in these melts.

  14. Development of conductivity probe and temperature probe for in-situ measurements in hydrological studies

    International Nuclear Information System (INIS)

    Chandra, U.; Galindo, B.J.; Castagnet, A.C.G.

    1981-05-01

    A conductivity probe and a temperature probe have been developed for in-situ measurements in various hydrological field studies. The conductivity probe has platinum electrodes and is powered with two 12 volt batteries. The sensing element of the temperature probe consists of a resistor of high coefficient of temperature. Response of the conductivity probe is measured in a milliampere mater while the resistance of the thermistor is read by a digital meter. The values of conductivity and temperature are derived from respective calibration. The probes are prototype and their range of measurement can be improved depending upon the requirement of the field problem. (Author) [pt

  15. Gas phase analysis of CO interactions with solid surfaces at high temperatures

    International Nuclear Information System (INIS)

    Anghel, Clara; Hoernlund, Erik; Hultquist, Gunnar; Limbaeck, Magnus

    2004-01-01

    An in situ method including mass spectrometry and labeled gases is presented and used to gain information on adsorption of molecules at high temperatures (>300 deg. C). Isotopic exchange rate in H 2 upon exposure to an oxidized zicaloy-2 sample and exchange rate in CO upon exposure to various materials have been measured. From these measurements, molecular dissociation rates in respective system have been calculated. The influence of CO and N 2 on the uptake rate of H 2 in zirconium and oxidized zicaloy-2 is discussed in terms of tendency for adsorption at high temperatures. In the case of oxidized Cr exposed to CO gas with 12 C, 13 C, 16 O and 18 O, the influence of H 2 O is investigated with respect to dissociation of CO molecules. The presented data supports a view of different tendencies for molecular adsorption of H 2 O, CO, N 2 , and H 2 molecules on surfaces at high temperatures

  16. Elevated temperature and high pressure large helium gas loop

    International Nuclear Information System (INIS)

    Sakasai, Minoru; Midoriyama, Shigeru; Miyata, Toyohiko; Nakase, Tsuyoshi; Izaki, Makoto

    1979-01-01

    The development of high temperature gas-cooled reactors especially aiming at the multi-purpose utilization of nuclear heat energy is carried out actively in Japan and West Germany. In Japan, the experimental HTGR of 50 MWt and 1000 deg C outlet temperature is being developed by Japan Atomic Energy Research Institute and others since 1969, and the development of direct iron-making technology utilizing high temperature reducing gas was started in 1973 as the large project of Ministry of Internalional Trade and Industry. Kawasaki Heavy Industries, Ltd., Has taken part in these development projects, and has developed many softwares for nuclear heat design, system design and safety design of nuclear reactor system and heat utilization system. In hardwares also, efforts have been exerted to develop the technologies of design and manufacture of high temperature machinery and equipments. The high temperature, high pressure, large helium gas loop is under construction in the technical research institute of the company, and it is expected to be completed in December, 1979. The tests planned are that of proving the dynamic performances of the loop and its machinery and equipments and the verification of analysis codes. The loop is composed of the main circulation system, the objects of testing, the helium gas purifying system, the helium supplying and evacuating system, instruments and others. (Kako, I.)

  17. Tunable photonic cavities for in-situ spectroscopic trace gas detection

    Science.gov (United States)

    Bond, Tiziana; Cole, Garrett; Goddard, Lynford

    2012-11-13

    Compact tunable optical cavities are provided for in-situ NIR spectroscopy. MEMS-tunable VCSEL platforms represents a solid foundation for a new class of compact, sensitive and fiber compatible sensors for fieldable, real-time, multiplexed gas detection systems. Detection limits for gases with NIR cross-sections such as O.sub.2, CH.sub.4, CO.sub.x and NO.sub.x have been predicted to approximately span from 10.sup.ths to 10s of parts per million. Exemplary oxygen detection design and a process for 760 nm continuously tunable VCSELS is provided. This technology enables in-situ self-calibrating platforms with adaptive monitoring by exploiting Photonic FPGAs.

  18. Gas-phase advanced oxidation for effective, efficient in situ control of pollution

    DEFF Research Database (Denmark)

    Johnson, Matthew Stanley; Nilsson, Elna Johanna Kristina; Svensson, Erik Anders

    2014-01-01

    In this article, gas-phase advanced oxidation, a new method for pollution control building on the photo-oxidation and particle formation chemistry occurring in the atmosphere, is introduced and characterized. The process uses ozone and UV-C light to produce in situ radicals to oxidize pollution......, generating particles that are removed by a filter; ozone is removed using a MnO2 honeycomb catalyst. This combination of in situ processes removes a wide range of pollutants with a comparatively low specific energy input. Two proof-of-concept devices were built to test and optimize the process...... particulate mass. Secondary pollution including formaldehyde and ultrafine particles might be generated, depending on the composition of the primary pollution....

  19. Tuning the structure of platinum particles on ceria in situ for enhancing the catalytic performance of exhaust gas catalysts

    International Nuclear Information System (INIS)

    Gaenzler, Andreas M.; Casapu, Maria; Grunwaldt, Jan-Dierk; Vernoux, Philippe; Loridant, Stephane; Cadete Santos Aires, Francisco J.; Epicier, Thierry; Betz, Benjamin; Hoyer, Ruediger

    2017-01-01

    A dynamic structural behavior of Pt nanoparticles on the ceria surface under reducing/oxidizing conditions was found at moderate temperatures (<500 C) and exploited to enhance the catalytic activity of Pt/CeO 2 -based exhaust gas catalysts. Redispersion of platinum in an oxidizing atmosphere already occurred at 400 C. A protocol with reducing pulses at 250-400 C was applied in a subsequent step for controlled Pt-particle formation. Operando X-ray absorption spectroscopy unraveled the different extent of reduction and sintering of Pt particles: The choice of the reductant allowed the tuning of the reduction degree/particle size and thus the catalytic activity (CO>H 2 >C 3 H 6 ). This dynamic nature of Pt on ceria at such low temperatures (250-500 C) was additionally confirmed by in situ environmental transmission electron microscopy. A general concept is proposed to adjust the noble metal dispersion (size, structure), for example, during operation of an exhaust gas catalyst. (copyright 2017 Wiley-VCH Verlag GmbH and Co. KGaA, Weinheim)

  20. Tuning the structure of platinum particles on ceria in situ for enhancing the catalytic performance of exhaust gas catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Gaenzler, Andreas M.; Casapu, Maria; Grunwaldt, Jan-Dierk [Institute for Chemical Technology and Polymer Chemistry (ITCP), Karlsruhe Institute of Technology (KIT), Karlsruhe (Germany); Vernoux, Philippe; Loridant, Stephane; Cadete Santos Aires, Francisco J. [Institut de Recherches sur la Catalyse et l' Environnement de Lyon, UMR 5256, CNRS, Universite Claude Bernard Lyon 1, Universite de Lyon, Villeurbanne (France); Epicier, Thierry [Materiaux, Ingenierie et Science, UMR 5510, CNRS, INSA de Lyon, Universite de Lyon, Villeurbanne (France); Betz, Benjamin [Umicore AG and Co. KG, Hanau (Germany); Ernst-Berl Institut, Technische Universitaet Darmstadt (Germany); Hoyer, Ruediger [Umicore AG and Co. KG, Hanau (Germany)

    2017-10-09

    A dynamic structural behavior of Pt nanoparticles on the ceria surface under reducing/oxidizing conditions was found at moderate temperatures (<500 C) and exploited to enhance the catalytic activity of Pt/CeO{sub 2}-based exhaust gas catalysts. Redispersion of platinum in an oxidizing atmosphere already occurred at 400 C. A protocol with reducing pulses at 250-400 C was applied in a subsequent step for controlled Pt-particle formation. Operando X-ray absorption spectroscopy unraveled the different extent of reduction and sintering of Pt particles: The choice of the reductant allowed the tuning of the reduction degree/particle size and thus the catalytic activity (CO>H{sub 2}>C{sub 3}H{sub 6}). This dynamic nature of Pt on ceria at such low temperatures (250-500 C) was additionally confirmed by in situ environmental transmission electron microscopy. A general concept is proposed to adjust the noble metal dispersion (size, structure), for example, during operation of an exhaust gas catalyst. (copyright 2017 Wiley-VCH Verlag GmbH and Co. KGaA, Weinheim)

  1. Microstructural Characterization of Low Temperature Gas Nitrided Martensitic Stainless Steel

    DEFF Research Database (Denmark)

    Fernandes, Frederico Augusto Pires; Christiansen, Thomas Lundin; Somers, Marcel A. J.

    2015-01-01

    The present work presents microstructural investigations of the surface zone of low temperature gas nitrided precipitation hardening martensitic stainless steel AISI 630. Grazing incidence X-ray diffraction was applied to investigate the present phases after successive removal of very thin sections...... of the sample surface. The development of epsilon nitride, expanded austenite and expanded martensite resulted from the low temperature nitriding treatments. The microstructural features, hardness and phase composition are discussed with emphasis on the influence of nitriding duration and nitriding potential....

  2. Preparation and Loading Process of Single Crystalline Samples into a Gas Environmental Cell Holder for In Situ Atomic Resolution Scanning Transmission Electron Microscopic Observation.

    Science.gov (United States)

    Straubinger, Rainer; Beyer, Andreas; Volz, Kerstin

    2016-06-01

    A reproducible way to transfer a single crystalline sample into a gas environmental cell holder for in situ transmission electron microscopic (TEM) analysis is shown in this study. As in situ holders have only single-tilt capability, it is necessary to prepare the sample precisely along a specific zone axis. This can be achieved by a very accurate focused ion beam lift-out preparation. We show a step-by-step procedure to prepare the sample and transfer it into the gas environmental cell. The sample material is a GaP/Ga(NAsP)/GaP multi-quantum well structure on Si. Scanning TEM observations prove that it is possible to achieve atomic resolution at very high temperatures in a nitrogen environment of 100,000 Pa.

  3. A review of helium gas turbine technology for high-temperature gas-cooled reactors

    International Nuclear Information System (INIS)

    No, Hee Cheon; Kim, Ji Hwan; Kim, Hyeun Min

    2007-01-01

    Current High-Temperature Gas-cooled Reactors (HTGRs) are based on a closed brayton cycle with helium gas as the working fluid. Thermodynamic performance of the axial-flow helium gas turbines is of critical concern as it considerably affects the overall cycle efficiency. Helium gas turbines pose some design challenges compared to steam or air turbomachinery because of the physical properties of helium and the uniqueness of the operating conditions at high pressure with low pressure ratio. This report present a review of the helium Brayton cycle experiences in Germany and in Japan. The design and availability of helium gas turbines for HTGR are also presented in this study. We have developed a new throughflow calculation code to calculate the design-point performance of helium gas turbines. Use of the method has been illustrated by applying it to the GTHTR300 reference

  4. First in situ plasma and neutral gas measurements at comet Halley: initial VEGA results

    International Nuclear Information System (INIS)

    Gringauz, K.I.; Remizov, A.P.; Gombosi, T.I.

    1986-04-01

    The first in situ observations and a description of the large scale behaviour of comet Halley's plasma environment are presented. The scientific objectives of the PLASMAG-1 experiment were as follows: to study the change of plasma parameters and distributions as a function of cometocentric distance; to investigate the existence and structure of the cometary bow shock; to determine the change in chemical composition of the heavily mass loaded plasma as the spacecraft approached the comet; and to measure the neutral gas distribution along the spacecraft trajectory. (author)

  5. In Situ Environmental TEM in Imaging Gas and Liquid Phase Chemical Reactions for Materials Research.

    Science.gov (United States)

    Wu, Jianbo; Shan, Hao; Chen, Wenlong; Gu, Xin; Tao, Peng; Song, Chengyi; Shang, Wen; Deng, Tao

    2016-11-01

    Gas and liquid phase chemical reactions cover a broad range of research areas in materials science and engineering, including the synthesis of nanomaterials and application of nanomaterials, for example, in the areas of sensing, energy storage and conversion, catalysis, and bio-related applications. Environmental transmission electron microscopy (ETEM) provides a unique opportunity for monitoring gas and liquid phase reactions because it enables the observation of those reactions at the ultra-high spatial resolution, which is not achievable through other techniques. Here, the fundamental science and technology developments of gas and liquid phase TEM that facilitate the mechanistic study of the gas and liquid phase chemical reactions are discussed. Combined with other characterization tools integrated in TEM, unprecedented material behaviors and reaction mechanisms are observed through the use of the in situ gas and liquid phase TEM. These observations and also the recent applications in this emerging area are described. The current challenges in the imaging process are also discussed, including the imaging speed, imaging resolution, and data management. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  6. Influence of different storage times and temperatures on blood gas ...

    African Journals Online (AJOL)

    The present study was designed to investigate the effects of storage temperature and time on blood gas and acid-base balance of ovine venous blood. Ten clinically healthy sheep were used in this study. A total number of 30 blood samples, were divided into three different groups, and were stored in a refrigerator adjusted ...

  7. Anisotropic ordering in a two-temperature lattice gas

    DEFF Research Database (Denmark)

    Szolnoki, Attila; Szabó, György; Mouritsen, Ole G.

    1997-01-01

    We consider a two-dimensional lattice gas model with repulsive nearest- and next-nearest-neighbor interactions that evolves in time according to anisotropic Kawasaki dynamics. The hopping of particles along the principal directions is governed by two heat baths at different temperatures T-x and T...

  8. Cluster tool for in situ processing and comprehensive characteriza tion of thin films at high temperatures.

    Science.gov (United States)

    Wenisch, Robert; Lungwitz, Frank; Hanf, Daniel; Heller, Rene; Zscharschuch, Jens; Hübner, René; von Borany, Johannes; Abrasonis, Gintautas; Gemming, Sibylle; Escobar-Galindo, Ramon; Krause, Matthias

    2018-05-31

    A new cluster tool for in situ real-time processing and depth-resolved compositional, structural and optical characterization of thin films at temperatures from -100 to 800 °C is described. The implemented techniques comprise magnetron sputtering, ion irradiation, Rutherford backscattering spectrometry, Raman spectroscopy and spectroscopic ellipsometry. The capability of the cluster tool is demonstrated for a layer stack MgO/ amorphous Si (~60 nm)/ Ag (~30 nm), deposited at room temperature and crystallized with partial layer exchange by heating up to 650°C. Its initial and final composition, stacking order and structure were monitored in situ in real time and a reaction progress was defined as a function of time and temperature.

  9. Assessing phase stability and element distribution in Co-base superalloys at elevated temperatures by in situ TEM heating experiments

    Energy Technology Data Exchange (ETDEWEB)

    Eggeler, Yolita; Mueller, Julian; Spiecker, Erdmann [Lehrstuhl fuer Mikro- und Nanostrukturforschung and Center for Nanoanalysis and Electron Microscopy (CENEM), Department Werkstoffwissenschaften, Universitaet Erlangen-Nuernberg, Erlangen (Germany)

    2016-07-01

    Co-based alloys, of a composition of Co-12Al-9W, form a stable two phase γ/γ{sup '} microstructure at 900 C. γ{sup '} cubes, consisting of the L12 crystal structure are coherently embedded in a solid solution fcc (A1) γ matrix. To ensure precipitate hardening at temperatures, which are relevant to practical applications, 700-1100 C, as experienced in gas turbine applications, the stability of the γ/γ{sup '} phases is of fundamental importance. In this analysis in situ TEM studies with chip-based heating systems (by DENS solution) are applied on new Co-based superalloys. After in situ heating at apr. 900 C and controlled quenching with different quenching rates the elemental distribution at the γ/γ{sup '} interface is measured using ChemiSTEM EDX. Exploiting the driving force for interface movement resulting from temperature-dependent volume fraction of γ and γ{sup '} insight into the diffusion of individual alloying elements and the relationship between local chemistry and ordering can be gained from transient phenomena. The experimental results will be compared with theoretical calculations. This work has been carried out within the framework of the SFB-TR 103 ''Single Crystal Superalloys''.

  10. Magnetic resonance studies of atomic hydrogen gas at low temperatures

    International Nuclear Information System (INIS)

    Hardy, W.N.; Morrow, M.; Jochemsen, R.; Statt, B.W.; Kubik, P.R.; Marsolais, R.M.; Berlinsky, A.J.; Landesman, A.

    1980-01-01

    Using a pulsed low temperature discharge in a closed cell containing H 2 and 4 He, we have been able to store a low density (approximately 10 12 atoms/cc) gas of atomic hydrogen for periods of order one hour in zero magnetic field and T=1 K. Pulsed magnetic resonance at the 1420 MHz hyperfine transition has been used to study a number of the properties of the gas, including the recombination rate H + H + 4 He→H 2 + 4 He, the hydrogen spin-exchange relaxation rates, the diffusion coefficient of H in 4 He gas and the pressure shift of the hyperfine frequency due to the 4 He buffer gas. Here we discuss the application of hyperfine frequency shifts as a probe of the H-He potential, and as a means for determining the binding energy of H on liquid helium

  11. Low temperature catalytic combustion of natural gas - hydrogen - air mixtures

    Energy Technology Data Exchange (ETDEWEB)

    Newson, E; Roth, F von; Hottinger, P; Truong, T B [Paul Scherrer Inst. (PSI), Villigen (Switzerland)

    1999-08-01

    The low temperature catalytic combustion of natural gas - air mixtures would allow the development of no-NO{sub x} burners for heating and power applications. Using commercially available catalysts, the room temperature ignition of methane-propane-air mixtures has been shown in laboratory reactors with combustion efficiencies over 95% and maximum temperatures less than 700{sup o}C. After a 500 hour stability test, severe deactivation of both methane and propane oxidation functions was observed. In cooperation with industrial partners, scaleup to 3 kW is being investigated together with startup dynamics and catalyst stability. (author) 3 figs., 3 refs.

  12. Field demonstration of ex situ biological treatability of contaminated groundwater at the Strachan gas plant

    International Nuclear Information System (INIS)

    Kurz, M.D.; Stepan, D.J.

    1997-03-01

    A multi-phase study was conducted to deal with the issues of groundwater and soil contamination by sour gas processing plants in Alberta. Phase One consisted of a review of all soil and groundwater monitoring data submitted to Alberta Environment by sour gas plants in accordance with the Canadian Clean Water Act. The current phase involves the development, evaluation and demonstration of selected remediation technologies to address subsurface contamination of sediments and groundwater at sour gas treatment plants with special attention to the presence of natural gas condensate in the subsurface. Results are presented from a pilot-scale biological treatability test that was performed at the Gulf Strachan Natural Gas Processing Plant in Rocky Mountain House, Alberta, where contaminated groundwater from the plant was being pumped to the surface through many recovery wells to control contaminant migration. The recovered groundwater was directed to a pump-and-treat system that consisted of oil-water separation, iron removal, hardness removal, and air stripping, before being reinjected. The pilot-scale biological treatability testing was conducted to evaluate process stability in treating groundwater without pretreatment for iron and hardness reduction and to evaluate the removal of organic contaminants. Results of a groundwater characterization analysis are discussed. Chemical characteristics of the groundwater at the Strachan Gas Plant showed that an ex situ remediation technology would address the dissolved volatile and semi-volatile organic contamination from natural gas condensates, as well as the nitrogenous compounds resulting from the use of amine-based process chemicals. 4 refs., 5 tabs., 4 figs

  13. In-situ heater test in sedimentary soft rocks under high temperature (Phase I)

    International Nuclear Information System (INIS)

    Ikenoya, Takafumi; Takakura, Nozomu; Okada, Tetsuji; Sawada, Masataka; Hirano, Kouhei; Tani, Kazuo

    2008-01-01

    Various researches have been conducted on high level radioactive waste geological disposal in sedimentary soft rocks. It's noted that the long-term mechanical behaviors of sedimentary soft rocks can be affected by various environmental factors such as temperatures or hydraulic conditions. Therefore, in-situ heater test was conducted in an underground cavern at a depth of 50 meters for the purpose of improving thermo-hydro-mechanical coupled analysis code. This report presents the test result demonstrating the changes of temperature and strain distributions with time at the elevated temperature of the heater up to 40 degrees Celsius. (author)

  14. In-situ temperature calibration below 1 K using the μ+ Knight shift in CMN

    International Nuclear Information System (INIS)

    Heffner, R.H.; Le, L.P.; Amato, A.; Baines, C.

    1996-01-01

    The authors present μ + paramagnetic shift measurements between 12 K and about 65 mK in cerium magnesium nitrate (CMN) to investigate its utility as an in-situ temperature calibration source for low temperature μSR experiments. CMN is a salt which exhibits Curie-law susceptibility to temperatures as low as 5 mK. The μ + Knight shift is measured to be (1.46 ± 0.03) x 10 -3 /T + (0.004 ± 0.02) x 10 -3 , corresponding to a transferred hyperfine field of -28.5 kOe/μ B

  15. FTIR analysis of flue gases - combined in-situ and dry extractive gas sampling; Kombination av in-situ och kallextraktiv roekgasmaetning med FTIR

    Energy Technology Data Exchange (ETDEWEB)

    Andersson, Christer; Soederbom, J [Vattenfall Utveckling AB, Aelvkarleby (Sweden)

    1996-10-01

    Fourier Transform Infra Red (FTIR) spectroscopy is a promising and versatile technique for gas analysis which lately has moved from the laboratory to industrial applications such as emission monitoring of combustion plants. This has been made possible by recent developments of spectrometers and software. The single most important advantage of the FTIR is its capability to simultaneously analyse virtually all gas species of interest in flue gas applications. The project has studied the feasibility of using the technique as a multi-component emission monitoring system. A specific aim was to evaluate different implementations of the technique to flue gas analysis: in-situ, hot/dry and cold extraction or combinations of these. The goal was to demonstrate a system in which gas components that normally require hot extraction (NH{sub 3}, HCl, H{sub 2}O) could instead be measured in-situ. In this way potential sampling artefacts e.g. for ammonia monitoring, can be avoided. The remaining gas components are measured using cold extraction and thereby minimizing interference from water. The latter advantage can be crucial for the accuracy of e.g. NO{sub x} measurements. Prior to the project start in-situ monitoring using FTIR was, a to a large extent, an untried method. The fact that broad band IR radiation can not be guided through optical fibres, presented a major technical obstacle. An `in-situ probe` was developed to serve the purpose. The probe is equipped with a gold plated mirror at the end and is mounted on the support structure of the FTIR-spectrometer. The arrangement proved to be a robust solution without being unnecessary complex or cumbersome to use. 10 refs, 45 figs, 10 tabs

  16. Determining noncondensible gas fractions at elevated temperatures and pressures using wet and dry bulb temperature measurements

    International Nuclear Information System (INIS)

    Griffith, P.; Bowman, J.

    1987-01-01

    The work reported in this note was undertaken to provide a method of determining the noncondensible gas fractions in a steam-gas mixture such as might be found in large reactor safety experiment like LOFT. In essence, the method used involves measuring the wet and dry bulb temperatures and using an algorithm, in place of the psychometric chart, to determine the partial pressure of the noncondensible gas in the mixture. In accomplishing this, the authors did the following: (1) extended the use of wet and dry-bulb temperature readings to determine mixture composition up to a temperature of 589 K and a pressure of 4.13 x 10 6 Pa. (2) developed an algorithm to reduce the data (3) found which materials would survive those temperatures

  17. Automated gas bubble imaging at sea floor – a new method of in situ gas flux quantification

    Directory of Open Access Journals (Sweden)

    G. Bohrmann

    2010-06-01

    Full Text Available Photo-optical systems are common in marine sciences and have been extensively used in coastal and deep-sea research. However, due to technical limitations in the past photo images had to be processed manually or semi-automatically. Recent advances in technology have rapidly improved image recording, storage and processing capabilities which are used in a new concept of automated in situ gas quantification by photo-optical detection. The design for an in situ high-speed image acquisition and automated data processing system is reported ("Bubblemeter". New strategies have been followed with regards to back-light illumination, bubble extraction, automated image processing and data management. This paper presents the design of the novel method, its validation procedures and calibration experiments. The system will be positioned and recovered from the sea floor using a remotely operated vehicle (ROV. It is able to measure bubble flux rates up to 10 L/min with a maximum error of 33% for worst case conditions. The Bubblemeter has been successfully deployed at a water depth of 1023 m at the Makran accretionary prism offshore Pakistan during a research expedition with R/V Meteor in November 2007.

  18. In-situ high temperature XRD of calcium phosphate biomaterial using DEHPA as the starting material

    International Nuclear Information System (INIS)

    Meor Yusoff Meor Sulaiman; Masliana Muslim

    2009-01-01

    A process to produce calcium phosphate biomaterial was done using an organic based phosphoric acid (DEHPA) as its starting material. The gel obtained from this reaction was used to study calcium phosphate transformation using in-situ XRD with temperature ranges from room temperature to 1300 degree C. The results obtained from this analysis show the following phase transformation: Gel β-Ca 2 P 2 O 7 β-TCP + HA α-TCP + HA, β-Ca 2 P 2 O 7 forms at 400 degree C and as we heat the sample at 1000 degree C peaks belonging to β- TCP and HA appears showing the transformation of the β-Ca 2 P 2 O 7 phase. When the sample is heated up further to 1200 degree C, β-TCP is transform into α-TCP. In the cold in-situ study, XRD analysis was performed on the sample from room temperature to -140 degree C. At room the XRD diffractogram shows the sample as an amorphous material and as the temperature was further lowered sharp peaks begins to form indicating that the material had becomes crystalline. The peaks were identified to be that calcium hydrogen phosphate (Ca(H 2 PO 4 ) 2 ) and this indicates that there is no hydroxyl group removal during the cooling process. The relative crystallinity values obtained for the different cooling temperatures show a slow exponential increase on the initial cooling of 0 to -100 degree C and at further cooling temperatures resulted fast and linear process. Also unlike the in-situ XRD analysis performs at high temperature no phase transformation occurred at this low temperature. (Author)

  19. Structure determination of an integral membrane protein at room temperature from crystals in situ

    International Nuclear Information System (INIS)

    Axford, Danny; Foadi, James; Hu, Nien-Jen; Choudhury, Hassanul Ghani; Iwata, So; Beis, Konstantinos; Evans, Gwyndaf; Alguel, Yilmaz

    2015-01-01

    The X-ray structure determination of an integral membrane protein using synchrotron diffraction data measured in situ at room temperature is demonstrated. The structure determination of an integral membrane protein using synchrotron X-ray diffraction data collected at room temperature directly in vapour-diffusion crystallization plates (in situ) is demonstrated. Exposing the crystals in situ eliminates manual sample handling and, since it is performed at room temperature, removes the complication of cryoprotection and potential structural anomalies induced by sample cryocooling. Essential to the method is the ability to limit radiation damage by recording a small amount of data per sample from many samples and subsequently assembling the resulting data sets using specialized software. The validity of this procedure is established by the structure determination of Haemophilus influenza TehA at 2.3 Å resolution. The method presented offers an effective protocol for the fast and efficient determination of membrane-protein structures at room temperature using third-generation synchrotron beamlines

  20. Structure determination of an integral membrane protein at room temperature from crystals in situ

    Energy Technology Data Exchange (ETDEWEB)

    Axford, Danny [Diamond Light Source, Harwell Science and Innovation Campus, Oxfordshire OX11 0DE (United Kingdom); Foadi, James [Diamond Light Source, Harwell Science and Innovation Campus, Oxfordshire OX11 0DE (United Kingdom); Imperial College London, London SW7 2AZ (United Kingdom); Hu, Nien-Jen; Choudhury, Hassanul Ghani [Diamond Light Source, Harwell Science and Innovation Campus, Oxfordshire OX11 0DE (United Kingdom); Imperial College London, London SW7 2AZ (United Kingdom); Rutherford Appleton Laboratory, Oxfordshire OX11 0FA (United Kingdom); Iwata, So [Diamond Light Source, Harwell Science and Innovation Campus, Oxfordshire OX11 0DE (United Kingdom); Diamond Light Source, Harwell Science and Innovation Campus, Oxfordshire OX11 0DE (United Kingdom); Imperial College London, London SW7 2AZ (United Kingdom); Rutherford Appleton Laboratory, Oxfordshire OX11 0FA (United Kingdom); Kyoto University, Kyoto 606-8501 (Japan); Beis, Konstantinos [Diamond Light Source, Harwell Science and Innovation Campus, Oxfordshire OX11 0DE (United Kingdom); Imperial College London, London SW7 2AZ (United Kingdom); Rutherford Appleton Laboratory, Oxfordshire OX11 0FA (United Kingdom); Evans, Gwyndaf, E-mail: gwyndaf.evans@diamond.ac.uk [Diamond Light Source, Harwell Science and Innovation Campus, Oxfordshire OX11 0DE (United Kingdom); Alguel, Yilmaz, E-mail: gwyndaf.evans@diamond.ac.uk [Diamond Light Source, Harwell Science and Innovation Campus, Oxfordshire OX11 0DE (United Kingdom); Imperial College London, London SW7 2AZ (United Kingdom); Rutherford Appleton Laboratory, Oxfordshire OX11 0FA (United Kingdom)

    2015-05-14

    The X-ray structure determination of an integral membrane protein using synchrotron diffraction data measured in situ at room temperature is demonstrated. The structure determination of an integral membrane protein using synchrotron X-ray diffraction data collected at room temperature directly in vapour-diffusion crystallization plates (in situ) is demonstrated. Exposing the crystals in situ eliminates manual sample handling and, since it is performed at room temperature, removes the complication of cryoprotection and potential structural anomalies induced by sample cryocooling. Essential to the method is the ability to limit radiation damage by recording a small amount of data per sample from many samples and subsequently assembling the resulting data sets using specialized software. The validity of this procedure is established by the structure determination of Haemophilus influenza TehA at 2.3 Å resolution. The method presented offers an effective protocol for the fast and efficient determination of membrane-protein structures at room temperature using third-generation synchrotron beamlines.

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

    Science.gov (United States)

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

    2018-02-01

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

  2. Temperature and distortion transients in gas tungsten-arc weldments

    International Nuclear Information System (INIS)

    Glickstein, S.S.; Friedman, E.

    1979-10-01

    An analysis and test program to develop a fundamental understanding of the gas tungsten-arc welding process has been undertaken at the Bettis Atomic Power Laboratory to develop techniques to determine and control the various welding parameters and weldment conditions so as to result in optimum weld response characteristics. These response characteristics include depth of penetration, weld bead configuration, weld bead sink and roll, distortion, and cracking sensitivity. The results are documented of that part of the program devoted to analytical and experimental investigations of temperatures, weld bead dimensions, and distortions for moving gas tungsten-arc welds applied to Alloy 600 plates

  3. Optimized Feature Extraction for Temperature-Modulated Gas Sensors

    Directory of Open Access Journals (Sweden)

    Alexander Vergara

    2009-01-01

    Full Text Available One of the most serious limitations to the practical utilization of solid-state gas sensors is the drift of their signal. Even if drift is rooted in the chemical and physical processes occurring in the sensor, improved signal processing is generally considered as a methodology to increase sensors stability. Several studies evidenced the augmented stability of time variable signals elicited by the modulation of either the gas concentration or the operating temperature. Furthermore, when time-variable signals are used, the extraction of features can be accomplished in shorter time with respect to the time necessary to calculate the usual features defined in steady-state conditions. In this paper, we discuss the stability properties of distinct dynamic features using an array of metal oxide semiconductors gas sensors whose working temperature is modulated with optimized multisinusoidal signals. Experiments were aimed at measuring the dispersion of sensors features in repeated sequences of a limited number of experimental conditions. Results evidenced that the features extracted during the temperature modulation reduce the multidimensional data dispersion among repeated measurements. In particular, the Energy Signal Vector provided an almost constant classification rate along the time with respect to the temperature modulation.

  4. In Situ Elevated Temperature Testing of Fly Ash Based Geopolymer Composites

    Science.gov (United States)

    Vickers, Les; Pan, Zhu; Tao, Zhong; van Riessen, Arie

    2016-01-01

    In situ elevated temperature investigations using fly ash based geopolymers filled with alumina aggregate were undertaken. Compressive strength and short term creep tests were carried out to determine the onset temperature of viscous flow. Fire testing using the standard cellulose curve was performed. Applying a load to the specimen as the temperature increased reduced the temperature at which viscous flow occurred (compared to test methods with no applied stress). Compressive strength increased at the elevated temperature and is attributed to viscous flow and sintering forming a more compact microstructure. The addition of alumina aggregate and reduction of water content reduced the thermal conductivity. This led to the earlier onset and shorter dehydration plateau duration times. However, crack formation was reduced and is attributed to smaller thermal gradients across the fire test specimen. PMID:28773568

  5. Low-temperature plasticity of olivine revisited with in situ TEM nanomechanical testing.

    Science.gov (United States)

    Idrissi, Hosni; Bollinger, Caroline; Boioli, Francesca; Schryvers, Dominique; Cordier, Patrick

    2016-03-01

    The rheology of the lithospheric mantle is fundamental to understanding how mantle convection couples with plate tectonics. However, olivine rheology at lithospheric conditions is still poorly understood because experiments are difficult in this temperature range where rocks and mineral become very brittle. We combine techniques of quantitative in situ tensile testing in a transmission electron microscope and numerical modeling of dislocation dynamics to constrain the low-temperature rheology of olivine. We find that the intrinsic ductility of olivine at low temperature is significantly lower than previously reported values, which were obtained under strain-hardened conditions. Using this method, we can anchor rheological laws determined at higher temperature and can provide a better constraint on intermediate temperatures relevant for the lithosphere. More generally, we demonstrate the possibility of characterizing the mechanical properties of specimens, which can be available in the form of submillimeter-sized particles only.

  6. In Situ Elevated Temperature Testing of Fly Ash Based Geopolymer Composites

    Directory of Open Access Journals (Sweden)

    Les Vickers

    2016-06-01

    Full Text Available In situ elevated temperature investigations using fly ash based geopolymers filled with alumina aggregate were undertaken. Compressive strength and short term creep tests were carried out to determine the onset temperature of viscous flow. Fire testing using the standard cellulose curve was performed. Applying a load to the specimen as the temperature increased reduced the temperature at which viscous flow occurred (compared to test methods with no applied stress. Compressive strength increased at the elevated temperature and is attributed to viscous flow and sintering forming a more compact microstructure. The addition of alumina aggregate and reduction of water content reduced the thermal conductivity. This led to the earlier onset and shorter dehydration plateau duration times. However, crack formation was reduced and is attributed to smaller thermal gradients across the fire test specimen.

  7. HM modelling of in-situ gas injection tests in bentonite and argillite: the PGZ experiment

    International Nuclear Information System (INIS)

    Gerard, P.; Charlier, R.; Radu, J.P.; La Vaissiere, R. de; Talandier, J.; Collin, F.

    2010-01-01

    Document available in extended abstract form only. During long-term repository of high and intermediate level nuclear waste in deep argillaceous geological formation, steel containers will corroded and organic material will be irradiated. The two processes lead mostly to hydrogen production. This study deals with the numerical modelling of the gas migration in both the host formation and a bentonite plug, with an emphasis on coupling between the gas transfer and the mechanical strains and stresses. More particularly the study aims to support the design of the PGZ in situ experiment that will be performed by Andra in its underground laboratory at Bure. The objective of the experiment is the analysis of the dynamics of the bentonite plug re-saturation, studying the competition between the liquid water coming from the argillite and a gas injection. The modelled experiment consists of a borehole drilled in rock clay, inside which a plug of MX-80 bentonite is set. The bentonite is naturally re-saturated by water coming from the host formation. At the same time a gas pressure, higher than the initial water pressure in the host rock, is imposed at both ends of the plug. The developed model takes into account the coupling between the mechanical behaviour and the water and gas transfers in undisturbed geo-materials. It manages explicitly liquid and vapour water, gaseous and dissolved hydrogen. Elastoplastic and non-linear elastic model are used to model the behaviour of, respectively, the argillaceous rock and the bentonite. The numerical results show the small desaturation obtained in bentonite and argillite. The influence of the coupling of the mechanic on the water and gas transfers is thus limited (due to the Bishop's effective stress). The swelling of the bentonite plug is not hindered by the gas migration and the confining effect of the engineered barrier is maintained. An analysis is made of the influence of the main transfer rock properties on the gas pressure

  8. Development of an in situ temperature stage for synchrotron X-ray spectromicroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Chakraborty, R., E-mail: rupak@alum.mit.edu, E-mail: buonassisi@mit.edu; Serdy, J.; Culpepper, M. L.; Buonassisi, T., E-mail: rupak@alum.mit.edu, E-mail: buonassisi@mit.edu [Department of Mechanical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States); West, B.; Stuckelberger, M.; Bertoni, M. I. [School of Electrical, Computer and Energy Engineering, Arizona State University, Tempe, Arizona 85287 (United States); Lai, B.; Maser, J. [Advanced Photon Source, Argonne National Laboratory, Argonne, Illinois 60439 (United States)

    2015-11-15

    In situ characterization of micro- and nanoscale defects in polycrystalline thin-film materials is required to elucidate the physics governing defect formation and evolution during photovoltaic device fabrication and operation. X-ray fluorescence spectromicroscopy is particularly well-suited to study defects in compound semiconductors, as it has a large information depth appropriate to study thick and complex materials, is sensitive to trace amounts of atomic species, and provides quantitative elemental information, non-destructively. Current in situ methods using this technique typically require extensive sample preparation. In this work, we design and build an in situ temperature stage to study defect kinetics in thin-film solar cells under actual processing conditions, requiring minimal sample preparation. Careful selection of construction materials also enables controlled non-oxidizing atmospheres inside the sample chamber such as H{sub 2}Se and H{sub 2}S. Temperature ramp rates of up to 300 °C/min are achieved, with a maximum sample temperature of 600 °C. As a case study, we use the stage for synchrotron X-ray fluorescence spectromicroscopy of CuIn{sub x}Ga{sub 1−x}Se{sub 2} (CIGS) thin-films and demonstrate predictable sample thermal drift for temperatures 25–400 °C, allowing features on the order of the resolution of the measurement technique (125 nm) to be tracked while heating. The stage enables previously unattainable in situ studies of nanoscale defect kinetics under industrially relevant processing conditions, allowing a deeper understanding of the relationship between material processing parameters, materials properties, and device performance.

  9. IAEA high temperature gas-cooled reactor activities

    International Nuclear Information System (INIS)

    Kendall, J.M.

    2000-01-01

    The IAEA activities on high temperature gas-cooled reactors are conducted with the review and support of the Member states, primarily through the International Working Group on Gas-Cooled Reactors (IWG-GCR). This paper summarises the results of the IAEA gas-cooled reactor project activities in recent years along with ongoing current activities through a review of Co-ordinated Research Projects (CRPs), meetings and other international efforts. A series of three recently completed CRPs have addressed the key areas of reactor physics for LEU fuel, retention of fission products and removal of post shutdown decay heat through passive heat transport mechanisms. These activities along with other completed and ongoing supporting CRPs and meetings are summarised with reference to detailed documentation of the results. (authors)

  10. In situ Low-temperature Pair Distribution Function (PDF) Analysis of CH4 and CO2 Hydrates

    Science.gov (United States)

    Cladek, B.; Everett, M.; McDonnell, M.; Tucker, M.; Keffer, D.; Rawn, C.

    2017-12-01

    Gas hydrates occur in ocean floor and sub-surface permafrost deposits and are stable at moderate to high pressures and low temperatures. They are a clathrate structure composed of hydrogen bonded water cages that accommodate a wide variety of guest molecules. CO2 and CH4 hydrates both crystallize as the cubic sI hydrate and can form a solid solution. Natural gas hydrates are interesting as a potential methane source and for CO2 sequestration. Long-range diffraction studies on gas hydrates give valuable structural information but do not provide a detailed understanding of the disordered gas molecule interactions with the host lattice. In-situ low temperature total scattering experiments combined with pair distribution function (PDF) analysis are used to investigate the gas molecule motions and guest-cage interactions. CO2 and methane hydrates exhibit different decomposition behavior, and CO2 hydrate has a smaller lattice parameter despite it being a relatively larger molecule. Total scattering studies characterizing both the short- and long-range order simultaneously help to elucidate the structural source of these phenomena. Low temperature neutron total scattering data were collected using the Nanoscale Ordered MAterials Diffractometer (NOMAD) beamline at the Spallation Neutron Source (SNS) on CO2 and CH4 hydrates synthesized with D2O. Guest molecule motion within cages and interactions between gases and cages are investigated through the hydrate stability and decomposition regions. Data were collected from 2-80 K at a pressure of 55 mbar on CO2 and CH4 hydrates, and from 80-270 K at 25 bar on CH4 hydrate. The hydrate systems were modeled with classical molecular dynamic (MD) simulations to provide an analysis of the total energy into guest-guest, guest-host and host-host contributions. Combined Reitveld and Reverse Monte Carlo (RMC) structure refinement were used to fit models of the data. This combined modeling and simulation characterizes the effects of CO2 and

  11. High temperature gas cleaning for pressurized gasification. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Alden, H.; Hagstroem, P.; Hallgren, A.; Waldheim, L. [TPS Termiska Processer AB, Nykoeping (Sweden)

    2000-04-01

    The purpose of the project was to build an apparatus to study pressurized, high temperature gas cleaning of raw gasification gas generated from biomass. A flexible and easy to operate pressurized apparatus was designed and installed for the investigations in high temperature gas cleaning by means of thermal, catalytic or chemical procedures. A semi continuos fuel feeding concept, at a maximum rate of 700 g/h, allowed a very constant formation of a gas product at 700 deg C. The gas product was subsequently introduced into a fixed bed secondary reactor where the actual gas cleanup or reformation was fulfilled. The installation work was divided into four work periods and apart from a few delays the work was carried out according to the time plan. During the first work period (January - June 1994) the technical design, drawings etc. of the reactor and additional parts were completed. All material for the construction was ordered and the installation work was started. The second work period (July - December 1994) was dedicated to the construction and the installation of the different components. Initial tests with the electrical heating elements, control system and gas supply were assigned to the third work period (January - June 1995). After the commissioning and the resulting modifications, initial pyrolysis and tar decomposition experiments were performed. During the fourth and final work period, (June - December 1995) encouraging results from first tests allowed the experimental part of the project work to commence, however in a slightly reduced program. The experimental part of the project work comparatively studied tar decomposition as a function of the process conditions as well as of the choice of catalyst. Two different catalysts, dolomite and a commercial Ni-based catalyst, were evaluated in the unit. Their tar cracking ability in the pressure interval 1 - 20 bar and at cracker bed temperatures between 800 - 900 deg C was compared. Long term tests to study

  12. Gas diffusion and temperature dependence of bubble nucleation during irradiation

    DEFF Research Database (Denmark)

    Foreman, A. J. E.; Singh, Bachu Narain

    1986-01-01

    The continuous production of gases at relatively high rates under fusion irradiation conditions may enhance the nucleation of cavities. This can cause dimensional changes and could induce embrittlement arising from gas accumulation on grain boundaries. Computer calculations have been made...... of the diatomic nucleation of helium bubbles, assuming helium to diffuse substitutionally, with radiation-enhanced diffusion at lower temperatures. The calculated temperature dependence of the bubble density shows excellent agreement with that observed in 600 MeV proton irradiations, including a reduction...... in activation energy below Tm/2. The coalescence of diatomic nuclei due to Brownian motion markedly improves the agreement and also provides a well-defined terminal density. Bubble nucleation by this mechanism is sufficiently fast to inhibit any appreciable initial loss of gas to grain boundaries during...

  13. Power Conversion Study for High Temperature Gas-Cooled Reactors

    International Nuclear Information System (INIS)

    Chang Oh; Richard Moore; Robert Barner

    2005-01-01

    The Idaho National Laboratory (INL) is investigating a Brayton cycle efficiency improvement on a high temperature gas-cooled reactor (HTGR) as part of Generation-IV nuclear engineering research initiative. There are some technical issues to be resolved before the selection of the final design of the high temperature gas cooled reactor, called as a Next Generation Nuclear Plant (NGNP), which is supposed to be built at the INEEL by year 2017. The technical issues are the selection of the working fluid, direct vs. indirect cycle, power cycle type, the optimized design in terms of a number of intercoolers, and others. In this paper, we investigated a number of working fluids for the power conversion loop, direct versus indirect cycle, the effect of intercoolers, and other thermal hydraulics issues. However, in this paper, we present part of the results we have obtained. HYSYS computer code was used along with a computer model developed using Visual Basic computer language

  14. Titanium dioxide thin films for high temperature gas sensors

    Energy Technology Data Exchange (ETDEWEB)

    Seeley, Zachary Mark; Bandyopadhyay, Amit; Bose, Susmita, E-mail: sbose@wsu.ed

    2010-10-29

    Titanium dioxide (TiO{sub 2}) thin film gas sensors were fabricated via the sol-gel method from a starting solution of titanium isopropoxide dissolved in methoxyethanol. Spin coating was used to deposit the sol on electroded aluminum oxide (Al{sub 2}O{sub 3}) substrates forming a film 1 {mu}m thick. The influence of crystallization temperature and operating temperature on crystalline phase, grain size, electronic conduction activation energy, and gas sensing response toward carbon monoxide (CO) and methane (CH{sub 4}) was studied. Pure anatase phase was found with crystallization temperatures up to 800 {sup o}C, however, rutile began to form by 900 {sup o}C. Grain size increased with increasing calcination temperature. Activation energy was dependent on crystallite size and phase. Sensing response toward CO and CH{sub 4} was dependent on both calcination and operating temperatures. Films crystallized at 650 {sup o}C and operated at 450 {sup o}C showed the best selectivity toward CO.

  15. Properties of super alloys for high temperature gas cooled reactor

    International Nuclear Information System (INIS)

    Izaki, Takashi; Nakai, Yasuo; Shimizu, Shigeki; Murakami, Takashi

    1975-01-01

    The existing data on the properties at high temperature in helium gas of iron base super alloys. Incoloy-800, -802 and -807, nickel base super alloys, Hastelloy-X, Inconel-600, -617 and -625, and a casting alloy HK-40 were collectively evaluated from the viewpoint of the selection of material for HTGRs. These properties include corrosion resistance, strength and toughness, weldability, tube making, formability, radioactivation, etc. Creep strength was specially studied, taking into consideration the data on the creep characteristics in the actual helium gas atmosphere. The necessity of further long run creep data is suggested. Hastelloy-X has completely stable corrosion resistance at high temperature in helium gas. Incoloy 800 and 807 and Inconel 617 are not preferable in view of corrosion resistance. The creep strength of Inconel 617 extraporated to 1,000 deg C for 100,000 hours in air was the greatest rupture strength of 0.6 kg/mm 2 in all above alloys. However, its strength in helium gas began to fall during a relatively short time, so that its creep strength must be re-evaluated in the use for long time. The radioactivation and separation of oxide film in primary construction materials came into question, Inconel 617 and Incoloy 807 showed high induced radioactivity intensity. Generally speaking, in case of nickel base alloys such as Hastelloy-X, oxide film is difficult to break away. (Iwakiri, K.)

  16. High-Temperature Gas-Cooled Test Reactor Point Design

    Energy Technology Data Exchange (ETDEWEB)

    Sterbentz, James William [Idaho National Laboratory; Bayless, Paul David [Idaho National Laboratory; Nelson, Lee Orville [Idaho National Laboratory; Gougar, Hans David [Idaho National Laboratory; Kinsey, James Carl [Idaho National Laboratory; Strydom, Gerhard [Idaho National Laboratory; Kumar, Akansha [Idaho National Laboratory

    2016-04-01

    A point design has been developed for a 200 MW high-temperature gas-cooled test reactor. The point design concept uses standard prismatic blocks and 15.5% enriched UCO fuel. Reactor physics and thermal-hydraulics simulations have been performed to characterize the capabilities of the design. In addition to the technical data, overviews are provided on the technological readiness level, licensing approach and costs.

  17. Treatment of low-temperature tar-gas mixtures

    Energy Technology Data Exchange (ETDEWEB)

    Schick, F

    1928-07-04

    Process for the treating and conversion of low-temperature tar-vapor and gas mixtures in the presence of metals or metal oxides as well as bodies of large surface, without previous condensation of the liquid material to be treated, characterized by the treatment taking place with a mixture of desulfurizing metals and metal oxides which, if necessary, are precipitated on carriers and large surface nonmetal cracking catalysts, such as active carbon and silica gel.

  18. Utilizing the response patterns of a temperature modulated chemoresistive gas sensor for gas diagnosis

    Energy Technology Data Exchange (ETDEWEB)

    Amini, Amir [Jannatabad College, Sama Organization, Islamic Azad University, Tehran (Iran, Islamic Republic of); Ghafarinia, Vahid, E-mail: amir.amini.elec@gmail.com, E-mail: ghafarinia@ee.kntu.ac.ir [Electrical Engineering Department, K. N. Toosi University of Technology, Tehran (Iran, Islamic Republic of)

    2011-02-15

    The observed features in the temporal response patterns of a temperature-modulated chemoresistive gas sensor were used for gas diagnosis. The patterns were recorded for clean air and air contaminated with different levels of some volatile organic compounds while a staircase heating voltage waveform had been applied to the microheater of a tin oxide gas sensor that modulated its operating temperature. Combining the steady-state and transient parameters of the recorded responses in the 50-400 deg. C range resulted in discriminatory feature vectors which were utilized for contaminant classification. The information content of these feature vectors was proved sufficient for discrimination of methanol, ethanol, 1-butanol, and acetone contaminations in a wide concentration range.

  19. Utilizing the response patterns of a temperature modulated chemoresistive gas sensor for gas diagnosis

    International Nuclear Information System (INIS)

    Amini, Amir; Ghafarinia, Vahid

    2011-01-01

    The observed features in the temporal response patterns of a temperature-modulated chemoresistive gas sensor were used for gas diagnosis. The patterns were recorded for clean air and air contaminated with different levels of some volatile organic compounds while a staircase heating voltage waveform had been applied to the microheater of a tin oxide gas sensor that modulated its operating temperature. Combining the steady-state and transient parameters of the recorded responses in the 50-400 deg. C range resulted in discriminatory feature vectors which were utilized for contaminant classification. The information content of these feature vectors was proved sufficient for discrimination of methanol, ethanol, 1-butanol, and acetone contaminations in a wide concentration range.

  20. The Influence of Mixing in High Temperature Gas Phase Reactions

    DEFF Research Database (Denmark)

    Østberg, Martin

    1996-01-01

    by injection of NH3 with carrier gas into the flue gas. NH3 can react with NO and form N2, but a competing reaction path is the oxidation of NH3 to NO.The SNR process is briefly described and it is shown by chemical kinetic modelling that OH radicals under the present conditions will initiate the reaction......The objective of this thesis is to describe the mixing in high temperature gas phase reactions.The Selective Non-Catalytic Reduction of NOx (referred as the SNR process) using NH3 as reductant was chosen as reaction system. This in-furnace denitrification process is made at around 1200 - 1300 K...... diffusion. The SNR process is simulated using the mixing model and an empirical kinetic model based on laboratory experiments.A bench scale reactor set-up has been built using a natural gas burner to provide the main reaction gas. The set-up has been used to perform an experimental investigation...

  1. Low-temperature thermal reduction of graphene oxide: In situ correlative structural, thermal desorption, and electrical transport measurements

    Science.gov (United States)

    Lipatov, Alexey; Guinel, Maxime J.-F.; Muratov, Dmitry S.; Vanyushin, Vladislav O.; Wilson, Peter M.; Kolmakov, Andrei; Sinitskii, Alexander

    2018-01-01

    Elucidation of the structural transformations in graphene oxide (GO) upon reduction remains an active and important area of research. We report the results of in situ heating experiments, during which electrical, mass spectrometry, X-ray photoelectron spectroscopy (XPS), Raman spectroscopy, and transmission electron microscopy (TEM) measurements were carried out correlatively. The simultaneous electrical and temperature programmed desorption measurements allowed us to correlate the onset of the increase in the electrical conductivity of GO by five orders of magnitude at about 150 °C with the maxima of the rates of desorption of H2O, CO, and CO2. Interestingly, this large conductivity change happens at an intermediate level of the reduction of GO, which likely corresponds to the point when the graphitic domains become large enough to enable percolative electronic transport. We demonstrate that the gas desorption is intimately related to (i) the changes in the chemical structure of GO detected by XPS and Raman spectroscopy and (ii) the formation of nanoscopic holes in GO sheets revealed by TEM. These in situ observations provide a better understanding of the mechanism of the GO thermal reduction.

  2. Study of the MWPC gas gain behaviour as a function of the gas pressure and temperature

    CERN Document Server

    Pinci, D

    2005-01-01

    The Muon System of the LHCb experiment is composed of five detection stations (M1-M5) equipped with 1368 Multi-Wire Proportional Chambers (MWPC) and 24 Triple-GEM detectors. The Multi Wire Proportional Chamber (MWPC) performances (detection efficiency, time resolution, pad-cluster size and ageing properties) are heavily dependent on the gas gain. The chamber gain depends on the gas density and therefore on the gas temperature and pressure. The impact of the environmental parameters on the MWPC gain has been studied in detail. The results, togheter with a simple method proposed to account for the gain variations, are reported in this note. The absolute gas gain at the testing voltage of 2750 V was also measured to be (1.2 +- 0.1)*10^5.

  3. Temperature profiles by ground-based remote sensing and in situ measurements

    Energy Technology Data Exchange (ETDEWEB)

    Argentini, S; Pietroni, I; Conidi, A; Mastrantonio, G; Petenko, I; Viola, A [ISAC-CNR, Via del Fosso del Cavaliere, 100, 00133 Roma (Italy); Gariazzo, C; Pelliccioni, A; Amicarelli, A [ISPESL Dipartimento Insediamenti Produttivi e Interazione con l' Ambiente, Via Fontana Candida, 1, 00040 Monteporzio Catone (RM) (Italy)], E-mail: s.argentini@isac.cnr.it

    2008-05-01

    This study focuses on the accuracy of the temperature profiles measured with a Doppler Radio-Acoustic Sounding System and a Microwave Temperature Profiler during a period of about 3 months in winter 2007-2008. The experiment was carried on at the experimental facility of the Institute of Atmospheric Sciences and Climate (ISAC) of the Italian National Research Council (CNR). The temperature data measured with remote sensors were verified with in situ measurements on a mast as well as with tethered balloon data. The facsimile echograms obtained with the ISAC Doppler SODAR were analysed to understand to which extent the RASS and Radiometer temperature profiles behaviour can represent the real thermal structure of the atmosphere.

  4. Temperature profiles by ground-based remote sensing and in situ measurements

    International Nuclear Information System (INIS)

    Argentini, S; Pietroni, I; Conidi, A; Mastrantonio, G; Petenko, I; Viola, A; Gariazzo, C; Pelliccioni, A; Amicarelli, A

    2008-01-01

    This study focuses on the accuracy of the temperature profiles measured with a Doppler Radio-Acoustic Sounding System and a Microwave Temperature Profiler during a period of about 3 months in winter 2007-2008. The experiment was carried on at the experimental facility of the Institute of Atmospheric Sciences and Climate (ISAC) of the Italian National Research Council (CNR). The temperature data measured with remote sensors were verified with in situ measurements on a mast as well as with tethered balloon data. The facsimile echograms obtained with the ISAC Doppler SODAR were analysed to understand to which extent the RASS and Radiometer temperature profiles behaviour can represent the real thermal structure of the atmosphere

  5. Po2 temperature blood factor for blood gas apparatus.

    Science.gov (United States)

    Teisseire, B P; Hérigault, R A; Teisseire, L J; Laurent, D N

    1984-01-01

    PO2 temperature formulae supplied by manufacturers on automatic blood gas apparatus, PO2 corr. = PO2 37 degrees C X 10F X delta T were studied and compared to the experimental determination of the delta log PO2/delta T ratio (Hérigault et al. [10]). Acid-base status at 37 degrees C appeared to have a measurable influence on the PO2 temperature factor; alkalosis increased the delta log PO2/delta T ratio, and the contrary was found for acidosis in comparison with normal acid-base status at 37 degrees C. For the same PO2, measured at 37 degrees C, all the proposed formulae of commercial blood gas automatic apparatus did not give the same temperature corrected PO2. The observed difference between the corrected PO2 may be important and greater than the precision of the initial measurement. To correct the measured PO2 for temperature, a relationship between delta log PO2/delta T and PO2 is proposed, between PO2 zero and PO2 180 mmHg, which takes into account measured pH and PO2 values at 37 degrees C:delta log PO2/delta T = [(-0.35 pH + 0.658) X 10(-4) X PO2] + 0.035.

  6. Analysis for In-situ Fission Rate Measurements using 4He Gas Scintillation Detectors

    International Nuclear Information System (INIS)

    Lewis, Jason M.; Raetz, Dominik; Jordan, Kelly A.; Murer, David

    2013-06-01

    Active neutron interrogation is a powerful NDA technique that relies on detecting and analyzing fission neutrons produced in a fuel sample by an interrogating high neutron flux. 4 He scintillation gas fast neutron detectors are investigated in this paper for use in a novel fission rate measurement technique The He-4 detectors have excellent gamma rejection, a fast response time, and give significant information on incident neutron energy allowing for energy cuts to be applied to the detected signal. These features are shown in this work to allow for the detection of prompt fission neutrons in-situ during active neutron interrogation of a 238 U sample. The energy spectrum from three different neutrons sources ( 252 Cf, AmBe, AmLi) is measured using the 4 He detection system and analyzed. An initial response matrix for the detector is determined using these measurements and the kinematic interaction properties of the elastic scattering with the 4 He. (authors)

  7. Laboratory investigations of Titan haze formation: In situ measurement of gas and particle composition

    Science.gov (United States)

    Hörst, Sarah M.; Yoon, Y. Heidi; Ugelow, Melissa S.; Parker, Alex H.; Li, Rui; de Gouw, Joost A.; Tolbert, Margaret A.

    2018-02-01

    Prior to the arrival of the Cassini-Huygens spacecraft, aerosol production in Titan's atmosphere was believed to begin in the stratosphere where chemical processes are predominantly initiated by far ultraviolet (FUV) radiation. However, measurements taken by the Cassini Ultraviolet Imaging Spectrograph (UVIS) and Cassini Plasma Spectrometer (CAPS) indicate that haze formation initiates in the thermosphere where there is a greater flux of extreme ultraviolet (EUV) photons and energetic particles available to initiate chemical reactions, including the destruction of N2. The discovery of previously unpredicted nitrogen species in measurements of Titan's atmosphere by the Cassini Ion and Neutral Mass Spectrometer (INMS) indicates that nitrogen participates in the chemistry to a much greater extent than was appreciated before Cassini. The degree of nitrogen incorporation in the haze particles is important for understanding the diversity of molecules that may be present in Titan's atmosphere and on its surface. We have conducted a series of Titan atmosphere simulation experiments using either spark discharge (Tesla coil) or FUV photons (deuterium lamp) to initiate chemistry in CH4/N2 gas mixtures ranging from 0.01% CH4/99.99% N2 to 10% CH4/90% N2. We obtained in situ real-time measurements using a high-resolution time-of-flight aerosol mass spectrometer (HR-ToF-AMS) to measure the particle composition as a function of particle size and a proton-transfer ion-trap mass spectrometer (PIT-MS) to measure the composition of gas phase products. These two techniques allow us to investigate the effect of energy source and initial CH4 concentration on the degree of nitrogen incorporation in both the gas and solid phase products. The results presented here confirm that FUV photons produce not only solid phase nitrogen bearing products but also gas phase nitrogen species. We find that in both the gas and solid phase, nitrogen is found in nitriles rather than amines and that both the

  8. In situ and laboratory toxicity of coalbed natural gas produced waters with elevated sodium bicarbonate

    Science.gov (United States)

    Farag, Aïda M.; Harper, David D.; Skaar, Don

    2014-01-01

    Some tributaries in the Powder River Structural Basin, USA, were historically ephemeral, but now contain water year round as a result of discharge of coalbed natural gas (CBNG)-produced waters. This presented the opportunity to study field sites with 100% effluent water with elevated concentrations of sodium bicarbonate. In situ experiments, static renewal experiments performed simultaneously with in situ experiments, and static renewal experiments performed with site water in the laboratory demonstrated that CBNG-produced water reduces survival of fathead minnow (Pimephales promelas) and pallid sturgeon (Scaphirhynchus albus). Age affected survival of fathead minnow, where fish 2 d posthatch (dph) were more sensitive than 6 dph fish, but pallid sturgeon survival was adversely affected at both 4 and 6 dph. This may have implications for acute assays that allow for the use of fish up to 14 dph. The survival of early lifestage fish is reduced significantly in the field when concentrations of NaHCO3 rise to more than 1500 mg/L (also expressed as >1245 mg HCO3 (-) /L). Treatment with the Higgin's Loop technology and dilution of untreated water increased survival in the laboratory. The mixing zones of the 3 outfalls studied ranged from approximately 800 m to 1200 m below the confluence. These experiments addressed the acute toxicity of effluent waters but did not address issues related to the volumes of water that may be added to the watershed.

  9. Development of high temperature gas cooled reactor in China

    Energy Technology Data Exchange (ETDEWEB)

    Guo, Wentao [Paul Scherrer Institute, Villigen (Switzerland). Dept. of Nuclear Energy and Safety; Schorer, Michael [Swiss Nuclear Forum, Olten (Switzerland)

    2018-02-15

    High temperature gas cooled reactor (HTGR) is one of the six Generation IV reactor types put forward by Generation IV International Forum (GIF) in 2002. This type of reactor has high outlet temperature. It uses Helium as coolant and graphite as moderator. Pebble fuel and ceramic reactor core are adopted. Inherit safety, good economy, high generating efficiency are the advantages of HTGR. According to the comprehensive evaluation from the international nuclear community, HTGR has already been given the priority to the research and development for commercial use. A demonstration project of the High Temperature Reactor-Pebble-�bed Modules (HTR-PM) in Shidao Bay nuclear power plant in China is under construction. In this paper, the development history of HTGR in China and the current situation of HTR-PM will be introduced. The experiences from China may be taken as a reference by the international nuclear community.

  10. Molecular beam mass spectrometer equipped with a catalytic wall reactor for in situ studies in high temperature catalysis research

    International Nuclear Information System (INIS)

    Horn, R.; Ihmann, K.; Ihmann, J.; Jentoft, F.C.; Geske, M.; Taha, A.; Pelzer, K.; Schloegl, R.

    2006-01-01

    A newly developed apparatus combining a molecular beam mass spectrometer and a catalytic wall reactor is described. The setup has been developed for in situ studies of high temperature catalytic reactions (>1000 deg. C), which involve besides surface reactions also gas phase reactions in their mechanism. The goal is to identify gas phase radicals by threshold ionization. A tubular reactor, made from the catalytic material, is positioned in a vacuum chamber. Expansion of the gas through a 100 μm sampling orifice in the reactor wall into differentially pumped nozzle, skimmer, and collimator chambers leads to the formation of a molecular beam. A quadrupole mass spectrometer with electron impact ion source designed for molecular beam inlet and threshold ionization measurements is used as the analyzer. The sampling time from nozzle to detector is estimated to be less than 10 ms. A detection time resolution of up to 20 ms can be reached. The temperature of the reactor is measured by pyrometry. Besides a detailed description of the setup components and the physical background of the method, this article presents measurements showing the performance of the apparatus. After deriving the shape and width of the energy spread of the ionizing electrons from measurements on N 2 and He we estimated the detection limit in threshold ionization measurements using binary mixtures of CO in N 2 to be in the range of several hundreds of ppm. Mass spectra and threshold ionization measurements recorded during catalytic partial oxidation of methane at 1250 deg. C on a Pt catalyst are presented. The detection of CH 3 · radicals is successfully demonstrated

  11. Molecular beam mass spectrometer equipped with a catalytic wall reactor for in situ studies in high temperature catalysis research

    Science.gov (United States)

    Horn, R.; Ihmann, K.; Ihmann, J.; Jentoft, F. C.; Geske, M.; Taha, A.; Pelzer, K.; Schlögl, R.

    2006-05-01

    A newly developed apparatus combining a molecular beam mass spectrometer and a catalytic wall reactor is described. The setup has been developed for in situ studies of high temperature catalytic reactions (>1000°C), which involve besides surface reactions also gas phase reactions in their mechanism. The goal is to identify gas phase radicals by threshold ionization. A tubular reactor, made from the catalytic material, is positioned in a vacuum chamber. Expansion of the gas through a 100μm sampling orifice in the reactor wall into differentially pumped nozzle, skimmer, and collimator chambers leads to the formation of a molecular beam. A quadrupole mass spectrometer with electron impact ion source designed for molecular beam inlet and threshold ionization measurements is used as the analyzer. The sampling time from nozzle to detector is estimated to be less than 10ms. A detection time resolution of up to 20ms can be reached. The temperature of the reactor is measured by pyrometry. Besides a detailed description of the setup components and the physical background of the method, this article presents measurements showing the performance of the apparatus. After deriving the shape and width of the energy spread of the ionizing electrons from measurements on N2 and He we estimated the detection limit in threshold ionization measurements using binary mixtures of CO in N2 to be in the range of several hundreds of ppm. Mass spectra and threshold ionization measurements recorded during catalytic partial oxidation of methane at 1250°C on a Pt catalyst are presented. The detection of CH3• radicals is successfully demonstrated.

  12. Long-Term Water Temperature Variations in Daya Bay, China Using Satellite and In Situ Observations

    Directory of Open Access Journals (Sweden)

    Jing Yu

    2010-01-01

    Full Text Available Daya Bay is a shallow, semi-en closed bay in the northern section of the South China Sea. The present study analyzed variations of water temperature in Daya Bay over the past 21 years (1985 - 2005 using Advanced Very High Resolution Radiometer (AVHRR satellite remote sensing data and in situ observations. Results showed that AVHRR readings of sea surface temperature (SST increased by 0.07°C y-1. Linear regression anal y sis for monthly SST anomalies (SSTA showed a shift from negative to positive from 1995 - 1996, when the Daya Bay nuclear power station commenced operations in 1994. The slope of linear regression analysis for SSTA nearly doubled from 0.05 (1985 - 1993 to 0.09 (1994 - 2005. Monthly AVHRR images showed a thermal plume from the power station and revealed the in crease of SST over 21 years. In situ observations in water temperature also showed an in creasing trend for the same period (1985 - 2005. Variations in water temperature in Daya Bay were connected with climatic perturbations and in creasing human activity including thermal discharge from nuclear power stations and the rapid economic development around the bay area.

  13. Low Cost Al-Si Casting Alloy As In-Situ Composite for High Temperature Applications

    Science.gov (United States)

    Lee, Jonathan A.

    2000-01-01

    A new aluminum-silicon (Al-Si) alloy has been successfully developed at NASA- Marshall Space Flight Center (MSFC) that has significant improvement in tensile and fatigue strength at elevated temperatures (500 F-700 F). The alloy offers a number of benefits such as light weight, high hardness, low thermal expansion and high surface wear resistance. In hypereutectic form, this alloy is considered as an in-situ Al-Si composite with tensile strength of about 90% higher than the auto industry 390 alloy at 600 F. This composite is very economically produced by using either conventional permanent steel molds or die casting. The projected material cost is less than $0.90 per pound, and automotive components such as pistons can be cast for high production rate using conventional casting techniques with a low and fully accounted cost. Key Words: Metal matrix composites, In-situ composite, aluminum-silicon alloy, hypereutectic alloy, permanent mold casting, die casting.

  14. Low-temperature growth of polycrystalline Ge thin film on glass by in situ deposition and ex situ solid-phase crystallization for photovoltaic applications

    International Nuclear Information System (INIS)

    Tsao, Chao-Yang; Weber, Juergen W.; Campbell, Patrick; Widenborg, Per I.; Song, Dengyuan; Green, Martin A.

    2009-01-01

    Poly-crystalline germanium (poly-Ge) thin films have potential for lowering the manufacturing cost of photovoltaic devices especially in tandem solar cells, but high crystalline quality would be required. This work investigates the crystallinity of sputtered Ge thin films on glass prepared by in situ growth and ex situ solid-phase crystallization (SPC). Structural properties of the films were characterized by Raman, X-ray diffraction and ultraviolet-visible reflectance measurements. The results show the transition temperature from amorphous to polycrystalline is between 255 deg. C and 280 deg. C for in situ grown poly-Ge films, whereas the transition temperature is between 400 deg. C and 500 deg. C for films produced by SPC for a 20 h annealing time. The in situ growth in situ crystallized poly-Ge films at 450 deg. C exhibit significantly better crystalline quality than those formed by solid-phase crystallization at 600 deg. C. High crystalline quality at low substrate temperature obtained in this work suggests the poly-Ge films could be promising for use in thin film solar cells on glass.

  15. High-temperature gas effects on aerodynamic characteristics of waverider

    Directory of Open Access Journals (Sweden)

    Jun Liu

    2015-02-01

    Full Text Available This paper focuses on the analysis of high-temperature effect on a conical waverider and it is a typical configuration of near space vehicles. Two different gas models are used in the numerical simulations, namely the thermochemical non-equilibrium and perfect gas models. The non-equilibrium flow simulations are conducted with the usage of the parallel non-equilibrium program developed by the authors while the perfect gas flow simulations are carried out with the commercial software Fluent. The non-equilibrium code is validated with experimental results and grid sensitivity analysis is performed as well. Then, numerical simulations of the flow around the conical waverider with the two gas models are conducted. In the results, differences in the flow structures as well as aerodynamic performances of the conical waverider are compared. It is found that the thermochemical non-equilibrium effect is significant mainly near the windward boundary layer at the tail of the waverider, and the non-equilibrium influence makes the pressure center move forward to about 0.57% of the whole craft’s length at the altitude of 60 km.

  16. In Situ Observation of Gypsum-Anhydrite Transition at High Pressure and High Temperature

    Institute of Scientific and Technical Information of China (English)

    LIU Chuan-Jiang; ZHENG Hai-Fei

    2012-01-01

    An in-situ Raman spectroscopic study of gypsum-anhydrite transition under a saturated water condition at high pressure and high temperature is performed using a hydrothermal diamond anvil cell (HDAC).The experimental results show that gypsum dissolvs in water at ambient temperature and above 496 MPa.With increasing temperature,the anhydrite (CaSO4) phase precipitates at 250 320℃ in the pressure range of 1.0 1.5 GPa,indicating that under a saturated water condition,both stable conditions of pressure and temperature and high levels of Ca and SO4 ion concentrations in aqueous solution are essential for the formation of anhydrite.A linear relationship between the pressure and temperature for the precipitation of anhydrite is established as P(GPa) =0.0068T - 0.7126 (250℃≤T≤320℃).Anhydrite remained stable during rapid cooling of the sample chamber,showing that the gypsum-anhydrite transition involving both dissolution and precipitation processes is irreversible at high pressure and high temperature.%An in-situ Raman spectroscopic study of gypsum-anhydrite transition under a saturated water condition at high pressure and high temperature is performed using a hydrothermal diamond anvil cell (HDAC). The experimental results show that gypsum dissolvs in water at ambient temperature and above 496 Mpa. With increasing temperature, the anhydrite (CaSO4) phase precipitates at 250-320℃ in the pressure range of 1.0-1.5 Gpa, indicating that under a saturated water condition, both stable conditions of pressure and temperature and high levels of Ca and SO4 ion concentrations in aqueous solution are essential for the formation of anhydrite. A linear relationship between the pressure and temperature for the precipitation of anhydrite is established as P(Gpa) = 0.0068T - 0.7126 (250℃≤T≤320℃). Anhydrite remained stable during rapid cooling of the sample chamber, showing that the gypsum-anhydrite transition involving both dissolution and precipitation processes is

  17. High temperature friction and seizure in gas cooled nuclear reactors

    International Nuclear Information System (INIS)

    Cousseran, P.; Febvre, A.; Martin, R.; Roche, R.

    1978-01-01

    One of the most delicate problems encountered in the gas cooled nuclear reactors is the friction without lubrication in a dry and hot (800 0 C /1472 0 F) helium atmosphere even at very small velocity. The research and development programs are described together with special tribometers that operate at mode than 1000 0 C (1832 0 F) in dry helium. The most interesting test conditions and results are given for gas nitrited steels and for strongly alloyed Ni-Cr steels coated with chromium carbide by plasma sprayed. The effects of parameters live velocity, travelled distance, contact pressure, roughness, temperature and prolonged stops under charge are described together with the effects of negative phenomena like attachment and chattering [fr

  18. Startup analysis for a high temperature gas loaded heat pipe

    Science.gov (United States)

    Sockol, P. M.

    1973-01-01

    A model for the rapid startup of a high-temperature gas-loaded heat pipe is presented. A two-dimensional diffusion analysis is used to determine the rate of energy transport by the vapor between the hot and cold zones of the pipe. The vapor transport rate is then incorporated in a simple thermal model of the startup of a radiation-cooled heat pipe. Numerical results for an argon-lithium system show that radial diffusion to the cold wall can produce large vapor flow rates during a rapid startup. The results also show that startup is not initiated until the vapor pressure p sub v in the hot zone reaches a precise value proportional to the initial gas pressure p sub i. Through proper choice of p sub i, startup can be delayed until p sub v is large enough to support a heat-transfer rate sufficient to overcome a thermal load on the heat pipe.

  19. Modular high-temperature gas-cooled reactor

    International Nuclear Information System (INIS)

    Shepherd, L.R.

    1988-01-01

    The high financial risk involved in building large nuclear power reactors has been a major factor in halting investment in new plant and in bringing further technical development to a standstill. Increased public concern about the safety of nuclear plant, particularly after Chernobyl, has contributed to this stagnation. Financial and technical risk could be reduced considerably by going to small modular units, which would make it possible to build up power station capacity in small steps. Such modular plant, based on the helium-cooled high temperature reactor (HTR), offers remarkable advantages in terms of inherent safety characteristics, partly because of the relatively small size of the individual modules but more on account of the enormous thermal capacity and high temperature margins of the graphitic reactor assemblies. Assessments indicate that, in the USA, the cost of power from the modular systems would be less than that from conventional single reactor plant, up to about 600 MW(e), and only marginally greater above that level, a margin that should be offset by the shorter time required in bringing the modular units on line to earn revenue. The modular HTR would be particularly appropriate in the UK, because of the considerable British industrial background in gas-cooled reactors, and could be a suitable replacement for Magnox. The modular reactor would be particularly suited to combined heat and power schemes and would offer great potential for the eventual development of gas turbine power conversion and the production of high-temperature process heat. (author)

  20. Leaf Cutter Ant (Atta cephalotes) Soil Modification and In Situ CO2 Gas Dynamics in a Neotropical Wet Forest

    Science.gov (United States)

    Fernandez Bou, A. S.; Carrasquillo Quintana, O.; Dierick, D.; Harmon, T. C.; Johnson, S.; Schwendenmann, L.; Zelikova, T. J.

    2016-12-01

    The goal of this work is to advance our understanding of soil carbon cycling in highly productive neotropical wet forests. More specifically, we are investigating the influence of leaf cutter ants (LCA) on soil CO2 gas dynamics in primary and secondary forest soils at La Selva Biological Station, Costa Rica. LCA are the dominant herbivore in tropical Americas, responsible for as much as 50% of the total herbivory. Their presence is increasing and their range is expanding because of forest fragmentation and other human impacts. We installed gas sampling wells in LCA (Atta cephalotes) nest and control sites (non-nests in the same soil and forest settings). The experimental design encompassed land cover (primary and secondary forest) and soil type (residual and alluvial). We collected gas samples monthly over an 18-month period. Several of the LCA nests were abandoned during this period. Nevertheless, we continued to sample these sites for LCA legacy effects. In several of the sites, we also installed sensors to continuously monitor soil moisture content, temperature, and CO2 levels. Within the 18-month period we conducted a 2-month field campaign to collect soil and nest vent CO2 efflux data from 3 of the nest-control pairs. Integrating the various data sets, we observed that for most of the sites nest and control soils behaved similarly during the tropical dry season. However, during the wet season gas well CO2 concentrations increased in the control sites while levels in the nests remained at dry season levels. This outcome suggests that ants modify soil gas transport properties (e.g., tortuosity). In situ time series and efflux sampling campaign data corroborated these findings. Abandoned nest CO2 levels were similar to those of the active nests, supporting the notion of a legacy effect from LCA manipulations. For this work, the period of abandonment was relatively short (several months to 1 year maximum), which appears to be insufficient for estimating the

  1. In-situ neutron diffraction characterization of temperature dependence deformation in α-uranium

    Science.gov (United States)

    Calhoun, C. A.; Garlea, E.; Sisneros, T. A.; Agnew, S. R.

    2018-04-01

    In-situ strain neutron diffraction measurements were conducted at temperature on specimens coming from a clock-rolled α-uranium plate, and Elasto-Plastic Self-Consistent (EPSC) modeling was employed to interpret the findings. The modeling revealed that the active slip systems exhibit a thermally activated response, while deformation twinning remains athermal over the temperature ranges explored (25-150 °C). The modeling also allowed assessment of the effects of thermal residual stresses on the mechanical response during compression. These results are consistent with those from a prior study of room-temperature deformation, indicating that the thermal residual stresses strongly influence the internal strain evolution of grain families, as monitored with neutron diffraction, even though accounting for these residual stresses has little effect on the macroscopic flow curve, except in the elasto-plastic transition.

  2. Preferential adsorption of NH3 gas molecules on MWCNT defect sites probed using in situ Raman spectroscopy

    CSIR Research Space (South Africa)

    Chimowa, George

    2017-06-01

    Full Text Available The preferential adsorption of NH(sub3) gas molecules on multi-walled carbon nanotubes (MWCNTs) was studied using in situ Raman spectroscopy. It was observed that the full widths at half maximum of the G band and the intensity ratio I(sub2D...

  3. Charge collection in Si detectors irradiated in situ at superfluid helium temperature

    Science.gov (United States)

    Verbitskaya, Elena; Eremin, Vladimir; Zabrodskii, Andrei; Dehning, Bernd; Kurfürst, Christoph; Sapinski, Mariusz; Bartosik, Marcin R.; Egorov, Nicolai; Härkönen, Jaakko

    2015-10-01

    Silicon and diamond detectors operated in a superfluid helium bath are currently being considered for the upgrade of the LHC beam loss monitoring system. The detectors would be installed in immediate proximity of the superconducting coils of the triplet magnets. We present here the results of the in situ irradiation test for silicon detectors using 23 GeV protons while keeping the detectors at a temperature of 1.9 K. Red laser (630 nm) Transient Current Technique and DC current measurements were used to study the pulse response and collected charge for silicon detectors irradiated to a maximum radiation fluence of 1×1016 p/cm2. The dependence between collected charge and irradiation fluence was parameterized using the Hecht equation and assumption of a uniform electric field distribution. The collected charge was found to degrade with particle fluence for both bias polarities. We observed that the main factor responsible for this degradation was related to trapping of holes on the donor-type radiation-induced defects. In contrast to expectations, along with formation of donors, acceptor-type defects (electron traps) are introduced into the silicon bulk. This suggests that the current models describing charge collection in irradiated silicon detectors require an extension for taking into account trapping at low temperatures with a contribution of shallow levels. New in situ irradiation tests are needed and planned now to extend statistics of the results and gain a deeper insight into the physics of low temperature detector operation in harsh radiation environment.

  4. High-temperature gas-cooled reactors and process heat

    International Nuclear Information System (INIS)

    Kasten, P.R.

    1980-01-01

    High-Temperature Gas-Cooled Reactors (HTGRs) are fueled with ceramic-coated microspheres of uranium and thorium oxides/carbides embedded in graphite blocks which are cooled with helium. Promising areas of HTGR application are in cogeneration, energy transport using Heat Transfer Salt, recovery of oils from oil shale, steam reforming of methane for chemical production, coal gasification, and in energy transfer using chemical heat jpipes in the long term. Further, HTGRs could be used as the energy source for hydrogen production through thermochemical water splitting in the long term. The potential market for Process Heat HTGRs is 100-200 large units by about the year 2020

  5. Analysis of artificial fireplace logs by high temperature gas chromatography.

    Science.gov (United States)

    Kuk, Raymond J

    2002-11-01

    High temperature gas chromatography is used to analyze the wax of artificial fireplace logs (firelogs). Firelogs from several different manufacturers are studied and compared. This study shows that the wax within a single firelog is homogeneous and that the wax is also uniform throughout a multi-firelog package. Different brands are shown to have different wax compositions. Firelogs of the same brand, but purchased in different locations, also have different wax compositions. With this information it may be possible to associate an unknown firelog sample to a known sample, but a definitive statement of the origin cannot be made.

  6. A study of silver behavior in Gas-turbine High Temperature Gas-cooled Reactor

    International Nuclear Information System (INIS)

    Sawa, Kazuhiro; Tanaka, Toshiyuki

    1995-11-01

    A Gas-turbine High Temperature Gas-cooled Reactor (GT-HTGR) is one of the promising reactor systems of future HTGRs. In the design of GT-HTGR, behavior of fission products, especially of silver, is considered to be important from the view point of maintenance of gas-turbine. A study of silver behavior in the GT-HTGR was carried out based on current knowledge. The purposes of this study were to determine an importance of the silver problem quantitatively, countermeasures to the problem and items of future research and development which will be needed. In this study, inventory, fractional release from fuel, plateout in the primary circuit and radiation dose were evaluated, respectively. Based on this study, it is predicted that gamma-ray from plateout silver in gas-turbine system contributes about a half of total radiation dose after reactor shutdown. In future, more detail data for silver release from fuel, plateout behavior, etc. using the High Temperature Engineering Test Reactor (HTTR), for example, will be needed to carry out reasonable design. (author)

  7. Safety philosophy of gas turbine high temperature reactor (GTHTR300)

    International Nuclear Information System (INIS)

    Shoji Katanishi; Kazuhiko Kunitomi; Shusaku Shiozawa

    2002-01-01

    Japan Atomic Energy Research Institute (JAERI) has undertaken the study of an original design concept of gas turbine high temperature reactor, the GTHTR300. The general concept of this study is development of a greatly simplified design that leads to substantially reduced technical and cost requirements. Newly proposed design features enable the GTHTR300 to be an efficient and economically competitive reactor in 2010's. Also, the GTHTR300 fully takes advantage of its inherent safety characteristics. The safety philosophy of the GTHTR300 is developed based on the HTTR (High Temperature Engineering Test Reactor) of JAERI which is the first HTGR in Japan. Major features of the newly proposed safety philosophy for the GTHTR300 are described in this article. (authors)

  8. In Situ Observation of Gypsum-Anhydrite Transition at High Pressure and High Temperature

    International Nuclear Information System (INIS)

    Liu Chuan-Jiang; Zheng Hai-Fei

    2012-01-01

    An in-situ Raman spectroscopic study of gypsum-anhydrite transition under a saturated water condition at high pressure and high temperature is performed using a hydrothermal diamond anvil cell (HDAC). The experimental results show that gypsum dissolvs in water at ambient temperature and above 496 MPa. With increasing temperature, the anhydrite (CaSO 4 ) phase precipitates at 250–320°C in the pressure range of 1.0–1.5GPa, indicating that under a saturated water condition, both stable conditions of pressure and temperature and high levels of Ca and SO 4 ion concentrations in aqueous solution are essential for the formation of anhydrite. A linear relationship between the pressure and temperature for the precipitation of anhydrite is established as P(GPa) = 0.0068T−0.7126 (250°C≤T≤320°C). Anhydrite remained stable during rapid cooling of the sample chamber, showing that the gypsum-anhydrite transition involving both dissolution and precipitation processes is irreversible at high pressure and high temperature. (geophysics, astronomy, and astrophysics)

  9. Aerodynamic levitator for in situ x-ray structure measurements on high temperature and molten nuclear fuel materials

    Energy Technology Data Exchange (ETDEWEB)

    Weber, J. K. R.; Alderman, O. L. G. [Materials Development, Inc., Arlington Heights, Illinois 60004 (United States); Advanced Photon Source, Argonne National Laboratory, Argonne, Illinois 60439 (United States); Tamalonis, A.; Sendelbach, S. [Materials Development, Inc., Arlington Heights, Illinois 60004 (United States); Benmore, C. J. [Advanced Photon Source, Argonne National Laboratory, Argonne, Illinois 60439 (United States); Hebden, A.; Williamson, M. A. [Nuclear Engineering Division, Argonne National Laboratory, Argonne, Illinois 60439 (United States)

    2016-07-15

    An aerodynamic levitator with carbon dioxide laser beam heating was integrated with a hermetically sealed controlled atmosphere chamber and sample handling mechanism. The system enabled containment of radioactive samples and control of the process atmosphere chemistry. The chamber was typically operated at a pressure of approximately 0.9 bars to ensure containment of the materials being processed. Samples 2.5-3 mm in diameter were levitated in flowing gas to achieve containerless conditions. Levitated samples were heated to temperatures of up to 3500 °C with a partially focused carbon dioxide laser beam. Sample temperature was measured using an optical pyrometer. The sample environment was integrated with a high energy (100 keV) x-ray synchrotron beamline to enable in situ structure measurements to be made on levitated samples as they were heated, melted, and supercooled. The system was controlled from outside the x-ray beamline hutch by using a LabVIEW program. Measurements have been made on hot solid and molten uranium dioxide and binary uranium dioxide-zirconium dioxide compositions.

  10. In situ tryptophan-like fluorometers: assessing turbidity and temperature effects for freshwater applications.

    Science.gov (United States)

    Khamis, K; Sorensen, J P R; Bradley, C; Hannah, D M; Lapworth, D J; Stevens, R

    2015-04-01

    Tryptophan-like fluorescence (TLF) is an indicator of human influence on water quality as TLF peaks are associated with the input of labile organic carbon (e.g. sewage or farm waste) and its microbial breakdown. Hence, real-time measurement of TLF could be particularly useful for monitoring water quality at a higher temporal resolution than available hitherto. However, current understanding of TLF quenching/interference is limited for field deployable sensors. We present results from a rigorous test of two commercially available submersible tryptophan fluorometers (ex ∼ 285, em ∼ 350). Temperature quenching and turbidity interference were quantified in the laboratory and compensation algorithms developed. Field trials were then undertaken involving: (i) an extended deployment (28 days) in a small urban stream; and, (ii) depth profiling of an urban multi-level borehole. TLF was inversely related to water temperature (regression slope range: -1.57 to -2.50). Sediment particle size was identified as an important control on the turbidity specific TLF response, with signal amplification apparent 200 NTU for clay particles. Compensation algorithms significantly improved agreement between in situ and laboratory readings for baseflow and storm conditions in the stream. For the groundwater trial, there was an excellent agreement between laboratory and raw in situ TLF; temperature compensation provided only a marginal improvement, and turbidity corrections were unnecessary. These findings highlight the potential utility of real time TLF monitoring for a range of environmental applications (e.g. tracing polluting sources and monitoring groundwater contamination). However, in situations where high/variable suspended sediment loads or rapid changes in temperature are anticipated concurrent monitoring of turbidity and temperature is required and site specific calibration is recommended for long term, surface water monitoring.

  11. Reduced one-body density matrix of Tonks–Girardeau gas at finite temperature

    International Nuclear Information System (INIS)

    Fu Xiao-Chen; Hao Ya-Jiang

    2015-01-01

    With thermal Bose–Fermi mapping method, we investigate the Tonks–Girardeau gas at finite temperature. It is shown that at low temperature, the Tonks gas displays the Fermi-like density profiles, and with the increase in temperature, the Tonks gas distributes in wider region. The reduced one-body density matrix is diagonal dominant in the whole temperature region, and the off-diagonal elements shall vanish rapidly with the deviation from the diagonal part at high temperature. (paper)

  12. Mechanistic simulation of batch acetone-butanol-ethanol (ABE) fermentation with in situ gas stripping using Aspen Plus™.

    Science.gov (United States)

    Darkwah, Kwabena; Nokes, Sue E; Seay, Jeffrey R; Knutson, Barbara L

    2018-05-22

    Process simulations of batch fermentations with in situ product separation traditionally decouple these interdependent steps by simulating a separate "steady state" continuous fermentation and separation units. In this study, an integrated batch fermentation and separation process was simulated for a model system of acetone-butanol-ethanol (ABE) fermentation with in situ gas stripping, such that the fermentation kinetics are linked in real-time to the gas stripping process. A time-dependent cell growth, substrate utilization, and product production is translated to an Aspen Plus batch reactor. This approach capitalizes on the phase equilibria calculations of Aspen Plus to predict the effect of stripping on the ABE fermentation kinetics. The product profiles of the integrated fermentation and separation are shown to be sensitive to gas flow rate, unlike separate steady state fermentation and separation simulations. This study demonstrates the importance of coupled fermentation and separation simulation approaches for the systematic analyses of unsteady state processes.

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

    Energy Technology Data Exchange (ETDEWEB)

    Hanson, Ronald [Stanford Univ., CA (United States); Whitty, Kevin [Univ. of Utah, Salt Lake City, UT (United States)

    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.

  14. In-situ investigation of the microstructure evolution in nanocrystalline copper electrodeposits at room temperature

    DEFF Research Database (Denmark)

    Pantleon, Karen; Somers, Marcel A. J.

    2006-01-01

    The microstructure evolution in copper electrodeposits at room temperature (self-annealing) was investigated by means of x-ray diffraction analysis and simultaneous measurements of the electrical resistivity as a function of time. In situ studies were started immediately after deposition...... growth, crystallographic texture changes by multiple twinning, and a decrease of the electrical resistivity occurred as a function of time at room temperature. The kinetics of self-annealing is strongly affected by the layer thickness: the thinner the layer, the slower the microstructure evolution is......, and self-annealing is suppressed completely for a thin layer with 0.4 µm. The preferred crystallographic orientation of the as-deposited crystallites is suggested to cause the observed thickness dependence of the self-annealing kinetics. ©2006 American Institute of Physics...

  15. Compact low temperature scanning tunneling microscope with in-situ sample preparation capability

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jungdae [Department of Physics, The University of Texas, Austin, Texas 78712 (United States); Department of Physics and EHSRC, University of Ulsan, Ulsan 680-749 (Korea, Republic of); Nam, Hyoungdo; Schroeder, Allan; Shih, Chih-Kang, E-mail: shih@physics.utexas.edu [Department of Physics, The University of Texas, Austin, Texas 78712 (United States); Qin, Shengyong [Department of Physics, The University of Texas, Austin, Texas 78712 (United States); Department of Physics, University of Science and Technology of China, Hefei, Anhui 230026 (China); ICQD, Hefei National Laboratory for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei, Anhui 230026 (China); Kim, Sang-ui [Department of Physics and EHSRC, University of Ulsan, Ulsan 680-749 (Korea, Republic of); Eom, Daejin [Korea Research Institute of Standards and Science, Daejeon 305-340 (Korea, Republic of)

    2015-09-15

    We report on the design of a compact low temperature scanning tunneling microscope (STM) having in-situ sample preparation capability. The in-situ sample preparation chamber was designed to be compact allowing quick transfer of samples to the STM stage, which is ideal for preparing temperature sensitive samples such as ultra-thin metal films on semiconductor substrates. Conventional spring suspensions on the STM head often cause mechanical issues. To address this problem, we developed a simple vibration damper consisting of welded metal bellows and rubber pads. In addition, we developed a novel technique to ensure an ultra-high-vacuum (UHV) seal between the copper and stainless steel, which provides excellent reliability for cryostats operating in UHV. The performance of the STM was tested from 2 K to 77 K by using epitaxial thin Pb films on Si. Very high mechanical stability was achieved with clear atomic resolution even when using cryostats operating at 77 K. At 2 K, a clean superconducting gap was observed, and the spectrum was easily fit using the BCS density of states with negligible broadening.

  16. Compact low temperature scanning tunneling microscope with in-situ sample preparation capability.

    Science.gov (United States)

    Kim, Jungdae; Nam, Hyoungdo; Qin, Shengyong; Kim, Sang-ui; Schroeder, Allan; Eom, Daejin; Shih, Chih-Kang

    2015-09-01

    We report on the design of a compact low temperature scanning tunneling microscope (STM) having in-situ sample preparation capability. The in-situ sample preparation chamber was designed to be compact allowing quick transfer of samples to the STM stage, which is ideal for preparing temperature sensitive samples such as ultra-thin metal films on semiconductor substrates. Conventional spring suspensions on the STM head often cause mechanical issues. To address this problem, we developed a simple vibration damper consisting of welded metal bellows and rubber pads. In addition, we developed a novel technique to ensure an ultra-high-vacuum (UHV) seal between the copper and stainless steel, which provides excellent reliability for cryostats operating in UHV. The performance of the STM was tested from 2 K to 77 K by using epitaxial thin Pb films on Si. Very high mechanical stability was achieved with clear atomic resolution even when using cryostats operating at 77 K. At 2 K, a clean superconducting gap was observed, and the spectrum was easily fit using the BCS density of states with negligible broadening.

  17. The real gas behaviour of helium as a cooling medium for high-temperature reactors

    International Nuclear Information System (INIS)

    Hewing, G.

    1977-01-01

    The article describes the influence of the real gas behaviour on the variables of state for the helium gas and the effects on the design of high-temperature reactor plants. After explaining the basic equations for describing variables and changes of state of the real gas, the real and ideal gas behaviour is analysed. Finally, the influence of the real gas behaviour on the design of high-temperature reactors in one- and two-cycle plants is investigated. (orig.) [de

  18. Time and temperature dependence of cascade induced defect production in in situ experiments and computer simulation

    International Nuclear Information System (INIS)

    Ishino, Shiori

    1993-01-01

    Understanding of the defect production and annihilation processes in a cascade is important in modelling of radiation damage for establishing irradiation correlation. In situ observation of heavy ion radiation damage has a great prospect in this respect. Time and temperature dependence of formation and annihilation of vacancy clusters in a cascade with a time resolution of 30 ms has been studied with a facility which comprises a heavy ion accelerator and an electron microscope. Formation and annihilation rates of defect clusters have been separately measured by this technique. The observed processes have been analysed by simple kinetic equations, taking into account the sink effect of surface and the defect clusters themselves together with the annihilation process due to thermal emission of vacancies from the defect clusters. Another tool to study time and temperature dependence of defect production in a cascade is computer simulation. Recent results of molecular dynamics calculations on the temperature dependence of cascade evolution are presented, including directional and temperature dependence of the lengths of replacement collision sequences, temperature dependence of the process to reach thermal equilibrium and so on. These results are discussed under general time frame of radiation damage evolution covering from 10 -15 to 10 9 s, and several important issues for the general understanding have been identified. (orig.)

  19. Temperature profile and producer gas composition of high temperature air gasification of oil palm fronds

    International Nuclear Information System (INIS)

    Guangul, F M; Sulaiman, S A; Ramli, A

    2013-01-01

    Environmental pollution and scarcity of reliable energy source are the current pressing global problems which need a sustainable solution. Conversion of biomass to a producer gas through gasification process is one option to alleviate the aforementioned problems. In the current research the temperature profile and composition of the producer gas obtained from the gasification of oil palm fronds by using high temperature air were investigated and compared with unheated air. By preheating the gasifying air at 500°C the process temperature were improved and as a result the concentration of combustible gases and performance of the process were improved. The volumetric percentage of CO, CH4 and H2 were improved from 22.49, 1.98, and 9.67% to 24.98, to 2.48% and 13.58%, respectively. In addition, HHV, carbon conversion efficiency and cold gas efficiency were improver from 4.88 MJ/Nm3, 83.8% and 56.1% to 5.90 MJ/Nm3, 87.3% and 62.4%, respectively.

  20. Metaphysics methods development for high temperature gas cooled reactor analysis

    International Nuclear Information System (INIS)

    Seker, V.; Downar, T. J.

    2007-01-01

    Gas cooled reactors have been characterized as one of the most promising nuclear reactor concepts in the Generation-IV technology road map. Considerable research has been performed on the design and safety analysis of these reactors. However, the calculational tools being used to perform these analyses are not state-of-the-art and are not capable of performing detailed three-dimensional analyses. This paper presents the results of an effort to develop an improved thermal-hydraulic solver for the pebble bed type high temperature gas cooled reactors. The solution method is based on the porous medium approach and the momentum equation including the modified Ergun's resistance model for pebble bed is solved in three-dimensional geometry. The heat transfer in the pebble bed is modeled considering the local thermal non-equilibrium between the solid and gas, which results in two separate energy equations for each medium. The effective thermal conductivity of the pebble-bed can be calculated both from Zehner-Schluender and Robold correlations. Both the fluid flow and the heat transfer are modeled in three dimensional cylindrical coordinates and can be solved in steady-state and time dependent. The spatial discretization is performed using the finite volume method and the theta-method is used in the temporal discretization. A preliminary verification was performed by comparing the results with the experiments conducted at the SANA test facility. This facility is located at the Institute for Safety Research and Reactor Technology (ISR), Julich, Germany. Various experimental cases are modeled and good agreement in the gas and solid temperatures is observed. An on-going effort is to model the control rod ejection scenarios as described in the OECD/NEA/NSC PBMR-400 benchmark problem. In order to perform these analyses PARCS reactor simulator code will be coupled with the new thermal-hydraulic solver. Furthermore, some of the other anticipated accident scenarios in the benchmark

  1. A method for measuring the local gas pressure within a gas-flow stage in situ in the transmission electron microscope

    International Nuclear Information System (INIS)

    Colby, R.; Alsem, D.H.; Liyu, A.; Kabius, B.

    2015-01-01

    Environmental transmission electron microscopy (TEM) has enabled in situ experiments in a gaseous environment with high resolution imaging and spectroscopy. Addressing scientific challenges in areas such as catalysis, corrosion, and geochemistry can require pressures much higher than the ∼20 mbar achievable with a differentially pumped environmental TEM. Gas flow stages, in which the environment is contained between two semi-transparent thin membrane windows, have been demonstrated at pressures of several atmospheres. However, the relationship between the pressure at the sample and the pressure drop across the system is not clear for some geometries. We demonstrate a method for measuring the gas pressure at the sample by measuring the ratio of elastic to inelastic scattering and the defocus of the pair of thin windows. This method requires two energy filtered high-resolution TEM images that can be performed during an ongoing experiment, at the region of interest. The approach is demonstrated to measure greater than atmosphere pressures of N 2 gas using a commercially available gas-flow stage. This technique provides a means to ensure reproducible sample pressures between different experiments, and even between very differently designed gas-flow stages. - Highlights: • Method developed for measuring gas pressure within a gas-flow stage in the TEM. • EFTEM and CTF-fitting used to calculate amount and volume of gas. • Requires only a pair of images without leaving region of interest. • Demonstrated for P > 1 atm with a common commercial gas-flow stage

  2. Detection of gas-permeable fuel particles for highl 7490 temperature gas-cooled reactors

    International Nuclear Information System (INIS)

    Thiele, B.A.; Stinton, D.P.; Costanzo, D.A.

    1980-01-01

    Fuel for High-Temperature Gas-Cooled Reactors (HTGR) consists of uranium oxide-carbide and thoria microspheres coated with layers of pyrolytic carbon and silicon carbide. The pyrolytic carbon coatings must be gas-tight to perform properly during irradiation. Therefore, particles must be carefully characterized to determine the number of defective particles (ie bare kernels, and cracked or permeable coatings). Although techniques are available to determine the number of bare kernels or cracked coatings, no reliable technique has been available to measure coating permeability. This work describes a technique recently developed to determine whether coatings for a batch of particles are gas-tight or permeable. Although most of this study was performed on Biso-coated particles, the technique applies equally well to Triso-coated particles. About 150 randomly selected Biso-particle batches were studied in this work. These batches were first subjected to an 18-hr chlorination at 15000C, and the volatile thorium tetrachloride released through cracked or very permeable coatings was measured versus chlorination time. Chlorinated batches were also radiographed to detect any thorium that had migrated from the kernel into the coatings. From this work a technique was developed to determine coating permeability. This consists of an 18-hr chlorination of multiple samples without measurement of the heavy metal released. Each batch is then radiographed and the heavy metal diffusion within each particle is examined so it can be determined if a particle batch is permeable, slightly permeable, or gas-tight. (author)

  3. New deployment of high temperature gas-cooled reactor

    International Nuclear Information System (INIS)

    Sekimoto, Hiroshi; Tsuchie, Yasuo; Kunitomi, Kazuhiko; Shiozawa, Shusaku; Konuki, Kaoru; Inagaki, Yoshiyuki; Hayakawa, Hitoshi

    2002-01-01

    The high temperature gas-cooled reactor (HTGR) is now under a condition difficult to know it well, because of considering not only power generation, but also diverse applications of its nuclear heat, of having extremely different safe principle from that of conventional reactors, of having two types of pebble-bed and block which are extremely different types, of promoting its construction plan in South Africa, of including its application to disposition of Russian surplus weapons plutonium of less reporting HTTR in Japan in spite of its full operation, and so on. However, HTGR is expected for an extremely important nuclear reactor aiming at the next coming one of LWR. HTGR which is late started and developed under complete private leading, is strongly conscious at environmental problem since its beginning. Before 30 years when large scale HTGR was expected to operate, it advertised a merit to reduce wasted heat because of its high temperature. As ratio occupied by electricity expands among application of energies, ratio occupied by the other energies are larger. When considering applications except electric power, high temperature thermal energy from HTGR can be thought wider applications than that from LWR and so on. (G.K.)

  4. The Silicon Environment in Silica Polymorphs, Aluminosilicate Crystals and Melts: An In Situ High Temperature XAS Study

    International Nuclear Information System (INIS)

    Cormier, L.; Neuville, D. R.; Roux, J.; Ligny, D. de; Henderson, G. S.; Flank, A.-M.; Lagarde, P.

    2007-01-01

    High temperature X-ray absorption spectroscopy at the Si K-edge has been used to obtain in situ information on SiO2 phase transitions upon heating. Important modifications are observed for the XANES spectra of the high temperature polymorphs, in relation to disordering of the SiO4 tetrahedra beyond the short-range correlations. This paper also presents the XANES spectra of anorthite (CaAl2Si2O8) from room temperature up to the melt (1900 K). This study shows the possibilities for determining the Si environment in crystals and glasses up to the liquid state using in situ XANES measurements

  5. Utilization of multi-purpose high temperature gas-cooled reactors

    International Nuclear Information System (INIS)

    Kawada, Osamu; Onuki, Yoshiaki; Wasaoka, Takeshi.

    1974-01-01

    Concerning the utilization of multi-purpose high temperature gas-cooled reactors, the electric power generation with gas turbines is described: features of HTR-He gas turbine power plants; the state of development of He gas turbines; and combined cycle with gas turbines and steam turbines. The features of gas turbines concern heat dissipation into the environment and the mode of load operation. Outstanding work in the development of He gas turbines is that in Hochtemperatur Helium-Turbine Project in West Germany. The power generation with combined gas turbines and steam turbines appears to be superior to that with gas turbines alone. (Mori, K.)

  6. In situ bioremediation (natural attenuation) at a gas plant waste site

    International Nuclear Information System (INIS)

    Ginn, J.S.; Sims, R.C.

    1995-01-01

    A former manufactured gas plant (MGP) waste site in New York was evaluated with regard to natural attenuation of polycyclic aromatic hydrocarbons (PAHs). Parent-compound concentrations of PAHs within an aquifer plume were observed to decrease with time subsequent to source removal of coal tar. Biotransformation-potential studies indicated that indigenous microorganisms in soil from the site were capable of degrading naphthalene and phenanthrene. A biochemical metabolite of phenanthrene degradation, 1-hydroxy-2-naphthoic acid (1H2NA), was tentatively characterized in coal-tar-contaminated soil from the site-based on liquid chromatographic retention time. Kinetic information was developed for the disappearance of phenanthrene and 1H2NA in nonspiked contaminated soil at the site. The Microtox trademark bioassay was used to evaluate toxicity trends in contaminated soil at the site. Results from the Microtox trademark indicated a decreasing trend in toxicity with respect to time in contaminated site soil. Research results were evaluated with regard to the National Research Council's guidelines for evaluating in situ bioremediation, and were used to enhance site characterization and monitoring information for evaluating the role of bioremediation as part of natural attenuation of PAHs at coal-tar-contaminated sites

  7. Airborne In-Situ Trace Gas Measurements of Multiple Wildfires in California (2013-2014)

    Science.gov (United States)

    Iraci, L. T.; Yates, E. L.; Tanaka, T.; Roby, M.; Gore, W.; Clements, C. B.; Lareau, N.; Ambrosia, V. G.; Quayle, B.; Schroeder, W.

    2014-12-01

    Biomass burning emissions are an important source of a wide range of trace gases and particles that can impact local, regional and global air quality, climate forcing, biogeochemical cycles and human health. In the western US, wildfires dominate over prescribed fires, contributing to atmospheric trace gas budgets and regional and local air pollution. Limited sampling of emissions from wildfires means western US emission estimates rely largely on data from prescribed fires, which may not be a suitable proxy for wildfire emissions. We report here in-situ measurements of carbon dioxide, methane, ozone and water vapor from the plumes of a variety of wildfires sampled in California in the fire seasons of 2013 and 2014. Included in the analysis are the Rim Fire (August - October 2013, near Yosemite National Park), the Morgan Fire (September 2013, near Clayton, CA), and the El Portal Fire (July - August 2014, in Yosemite National Park), among others. When possible, fires were sampled on multiple days. Emission ratios and estimated emission factors will be presented and discussed in the context of fuel composition, plume structure, and fire phase. Correlations of plume chemical composition to MODIS/VIIRS Fire Radiative Power (FRP) and other remote sensing information will be explored. Furthermore, the role of plumes in delivery of enhanced ozone concentrations to downwind municipalities will be discussed.

  8. Combined synthesis and in situ coating of nanoparticles in the gas phase

    International Nuclear Information System (INIS)

    Laehde, Anna; Raula, Janne; Kauppinen, Esko I.

    2008-01-01

    Combined gas phase synthesis and coating of sodium chloride (NaCl) and lactose nanoparticles has been developed using an aerosol flow reactor. Nano-sized core particles were produced by the droplet-to-particle method and coated in situ by the physical vapour deposition of L-leucine vapour. The saturation of L-leucine in the reactor determined the resulting particle size and size distribution. In general, particle size increased with the addition of L-leucine and notable narrowing of the core particle size distribution was observed. In addition, homogeneous nucleation of the vapour, i.e. formation of pure L-leucine particles, was observed depending on the saturation conditions of L-leucine as well as the core particle characteristics. The effects of core particle properties, i.e. size and solid-state characteristics, on the coating process were studied by comparing the results for coated NaCl and lactose particles. During deposition, L-leucine formed a uniform coating on the surface of the core particles. The coating stabilised the nanoparticles and prevented the sintering of particles during storage.

  9. Assessment and status report High-Temperature Gas-Cooled Reactor gas-turbine technology

    International Nuclear Information System (INIS)

    1981-01-01

    Purpose of this report is to present a brief summary assessment of the High Temperature Gas-Cooled Reactor - Gas Turbine (HTGR-GT) technology. The focal point for the study was a potential 2000 MW(t)/800 MW(e) HTGR-GT commercial plant. Principal findings of the study were that: the HTGR-GT is feasible, but with significantly greater development risk than the HTGR-SC (Steam Cycle). At the level of performance corresponding to the reference design, no incremental economic incentive can be identified for the HTGR-GT to offset the increased development costs and risk relative to the HTGR-SC. The relative economics of the HTGR-GT and HTGR-SC are not significantly impacted by dry cooling considerations. While reduced cycel complexity may ultimately result in a reliability advantage for the HTGR-GT, the value of that potential advantage was not quantified

  10. i-anvils : in situ measurements of pressure, temperature and conductivity in diamond anvil cells

    Science.gov (United States)

    Munsch, P.; Bureau, H.; Kubsky, S.; Meijer, J.; Datchi, F.; Ninet, S.; Estève, I.

    2011-12-01

    The precise determination of the pressure and temperature conditions during diamond anvils cells (DAC) experiments is of primary importance. Such determinations are critical more especially for the fields corresponding to "low pressures" (micro-structures are implanted in the diamond anvil lattice a few micrometers below the surface, the sensors are located a few μm below the center of the diamond culet (sample chamber position). When conductive electrodes are implanted at the position of the sample chamber on the culet of the anvil, instead of P,T sensors, they allow in situ measurements of electrical properties of the loaded sample at high P,T conditions in a DAC. The principle consists of applying an electrical potential across the structures through external contacts placed on the slopes of the anvil. The resistivity of these structures is sensitive to pressure and temperature applied in the sample chamber. The electrical transport properties of the sample can be measured the same way when electrodes have been implanted on the culet. Here we will present our last progresses, more especially using the focus ion beam (FIB) technology to perform contacts and electrodes. Progresses about the i-anvils connexions with the electronic devices will also be shown. We will present the last P and T sensors calibrations. Furnaces are also introduced through Boron implantation into the anvils, allowing the possibility to reach intermediate temperatures between externally heated DAC (up to 1100°C) and laser heated DAC (from 1500°C to a few thousands). Preliminary tests and the interest of such devices will be discussed at the meeting. A new diamond anvil cell has been especially designed for this purpose. This DAC allows in situ spectroscopies and X-Ray characterisation of geological fluids in their equilibrium conditions in the crust and in the upper mantle. Preliminary results will be presented.

  11. Nanocalorimeter platform for in situ specific heat measurements and x-ray diffraction at low temperature

    Science.gov (United States)

    Willa, K.; Diao, Z.; Campanini, D.; Welp, U.; Divan, R.; Hudl, M.; Islam, Z.; Kwok, W.-K.; Rydh, A.

    2017-12-01

    Recent advances in electronics and nanofabrication have enabled membrane-based nanocalorimetry for measurements of the specific heat of microgram-sized samples. We have integrated a nanocalorimeter platform into a 4.5 T split-pair vertical-field magnet to allow for the simultaneous measurement of the specific heat and x-ray scattering in magnetic fields and at temperatures as low as 4 K. This multi-modal approach empowers researchers to directly correlate scattering experiments with insights from thermodynamic properties including structural, electronic, orbital, and magnetic phase transitions. The use of a nanocalorimeter sample platform enables numerous technical advantages: precise measurement and control of the sample temperature, quantification of beam heating effects, fast and precise positioning of the sample in the x-ray beam, and fast acquisition of x-ray scans over a wide temperature range without the need for time-consuming re-centering and re-alignment. Furthermore, on an YBa2Cu3O7-δ crystal and a copper foil, we demonstrate a novel approach to x-ray absorption spectroscopy by monitoring the change in sample temperature as a function of incident photon energy. Finally, we illustrate the new insights that can be gained from in situ structural and thermodynamic measurements by investigating the superheated state occurring at the first-order magneto-elastic phase transition of Fe2P, a material that is of interest for magnetocaloric applications.

  12. Single-Crystal Tungsten Carbide in High-Temperature In-Situ Additive Manufacturing Characterization

    Energy Technology Data Exchange (ETDEWEB)

    Kolopus, James A. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Boatner, Lynn A. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2017-05-18

    Nanoindenters are commonly used for measuring the mechanical properties of a wide variety of materials with both industrial and scientific applications. Typically, these instruments employ an indenter made of a material of suitable hardness bonded to an appropriate shaft or holder to create an indentation on the material being tested. While a variety of materials may be employed for the indenter, diamond and boron carbide are by far the most common materials used due to their hardness and other desirable properties. However, as the increasing complexity of new materials demands a broader range of testing capabilities, conventional indenter materials exhibit significant performance limitations. Among these are the inability of diamond indenters to perform in-situ measurements at temperatures above 600oC in air due to oxidation of the diamond material and subsequent degradation of the indenters mechanical properties. Similarly, boron carbide also fails at high temperature due to fracture. [1] Transition metal carbides possess a combination of hardness and mechanical properties at high temperatures that offer an attractive alternative to conventional indenter materials. Here we describe the technical aspects for the growth of single-crystal tungsten carbide (WC) for use as a high-temperature indenter material, and we examine a possible approach to brazing these crystals to a suitable mount for grinding and attachment to the indenter instrument. The use of a by-product of the recovery process is also suggested as possibly having commercial value.

  13. In-situ high-temperature Raman spectroscopic studies of aluminosilicate liquids

    Science.gov (United States)

    Daniel, Isabelle; Gillet, Philippe; Poe, Brent T.; McMillan, Paul F.

    1995-03-01

    We have measured in-situ Raman spectra of aluminosilicate glasses and liquids with albite (NaAlSi3 O8) and anorthite (CaAl2Si2O8) compositions at high temperatures, through their glass transition range up to 1700 and 2000 K, respectively. For these experiments, we have used a wire-loop heating device coupled with micro-Raman spectroscopy, in order to achieve effective spatial filtering of the extraneous thermal radiation. A major concern in this work is the development of methodology for reliably extracting the first and second order contributions to the Raman scattering spectra of aluminosilicate glasses and liquids from the high temperature experimental data, and analyzing these in terms of vibrational (anharmonic) and configurational changes. The changes in the first order Raman spectra with temperature are subtle. The principal low frequency band remains nearly constant with increasing temperature, indicating little change in the T-O-T angle, and that the angle bending vibration is quite harmonic. This is in contrast to vitreous SiO2, studied previously. Above Tg, intensity changes in the 560 590 cm-1 regions of both sets of spectra indicate configurational changes in the supercooled liquids, associated with formation of additional Al-O-Al linkages, or 3-membered (Al, Si)-containing rings. Additional intensity at 800 cm-1 reflects also some rearrangement of the Si-O-Al network.

  14. Medium-size high-temperature gas-cooled reactor

    International Nuclear Information System (INIS)

    Peinado, C.O.; Koutz, S.L.

    1980-08-01

    This report summarizes high-temperature gas-cooled reactor (HTGR) experience for the 40-MW(e) Peach Bottom Nuclear Generating Station of Philadelphia Electric Company and the 330-MW(e) Fort St. Vrain Nuclear Generating Station of the Public Service Company of Colorado. Both reactors are graphite moderated and helium cooled, operating at approx. 760 0 C (1400 0 F) and using the uranium/thorium fuel cycle. The plants have demonstrated the inherent safety characteristics, the low activation of components, and the high efficiency associated with the HTGR concept. This experience has been translated into the conceptual design of a medium-sized 1170-MW(t) HTGR for generation of 450 MW of electric power. The concept incorporates inherent HTGR safety characteristics [a multiply redundant prestressed concrete reactor vessel (PCRV), a graphite core, and an inert single-phase coolant] and engineered safety features

  15. Advances in High Temperature Gas Cooled Reactor Fuel Technology

    International Nuclear Information System (INIS)

    2012-12-01

    This publication reports on the results of a coordinated research project on advances in high temperature gas cooled reactor (HTGR) fuel technology and describes the findings of research activities on coated particle developments. These comprise two specific benchmark exercises with the application of HTGR fuel performance and fission product release codes, which helped compare the quality and validity of the computer models against experimental data. The project participants also examined techniques for fuel characterization and advanced quality assessment/quality control. The key exercise included a round-robin experimental study on the measurements of fuel kernel and particle coating properties of recent Korean, South African and US coated particle productions applying the respective qualification measures of each participating Member State. The summary report documents the results and conclusions achieved by the project and underlines the added value to contemporary knowledge on HTGR fuel.

  16. Advances in High Temperature Gas Cooled Reactor Fuel Technology

    International Nuclear Information System (INIS)

    2012-06-01

    This publication reports on the results of a coordinated research project on advances in high temperature gas cooled reactor (HTGR) fuel technology and describes the findings of research activities on coated particle developments. These comprise two specific benchmark exercises with the application of HTGR fuel performance and fission product release codes, which helped compare the quality and validity of the computer models against experimental data. The project participants also examined techniques for fuel characterization and advanced quality assessment/quality control. The key exercise included a round-robin experimental study on the measurements of fuel kernel and particle coating properties of recent Korean, South African and US coated particle productions applying the respective qualification measures of each participating Member State. The summary report documents the results and conclusions achieved by the project and underlines the added value to contemporary knowledge on HTGR fuel.

  17. Safety analysis of a high temperature gas-cooled reactor

    International Nuclear Information System (INIS)

    Shimazu, Akira; Morimoto, Toshio

    1975-01-01

    In recent years, in order to satisfy the social requirements of environment and safety and also to cope with the current energy stringency, the installation of safe nuclear power plants is indispensable. Herein, safety analysis and evaluation to confirm quantitatively the safety design of a nuclear power plant become more and more important. The safety analysis and its methods for a high temperature gas-cooled reactor are described, with emphasis placed on the practices by Fuji Electric Manufacturing Co. Fundamental rule of securing plant safety ; safety analysis in normal operation regarding plant dynamic characteristics and radioactivity evaluation ; and safety analysis at the time of accidents regarding plant response to the accidents and radioactivity evaluation are explained. (Mori, K.)

  18. Control of temperature distribution in a supercritical gas extraction tower

    International Nuclear Information System (INIS)

    Yoshida, M.; Matsumoto, S.; Honda, G.; Iwama, T.; Suzuki, Y.; Odagiri, S.

    1989-01-01

    A control scheme recently proposed by the authors is applied to the control of axial temperature distribution in a bench-scale supercritical-gas extractor. The extraction unit is constructed from a packed column 3 m long covered by a coaxial cylindrical casing. Although the actual structure of the extractor is very complicated, it is modeled by a simple double-pipe and therefore its mathematical model can be described by a pair of partial differential equations. The models are reduced to a lumped parameter system with a finite dimension by use of the finite Fourier transform technique. The controller is designed on the basis of the reduced model. An extended Kalman filter is used to estimate simultaneously the state variables and the unknown parameters. The results demonstrate that both the state estimation and the controller performance are satisfactory. This implies that the control scheme is very robust in spite of the incompleteness of the model used

  19. Working gas temperature and pressure changes for microscale thermal creep-driven flow caused by discontinuous wall temperatures

    International Nuclear Information System (INIS)

    Han, Yen-Lin

    2010-01-01

    Microscale temperature gradient-driven (thermal creep/transpiration) gas flows have attracted significant interest during the past decade. For free molecular and transitional conditions, applying temperature gradients to a flow channel's walls induces the thermal creep effect. This results in a working gas flowing through the channel from cold to hot, which is generally accompanied by a rising pressure from cold to hot in the channel. Working gas temperature and pressure distributions can vary significantly, depending on a flow channel's configuration and wall temperature distribution. Understanding working gas temperature excursions, both increases and decreases, is essential to ensure the effective use of thermal creep flows in microscale applications. In this study, the characterizations of working gas temperature variations, due to both temperature discontinuities and more gradual changes, on a variety of flow channel walls, were systematically investigated using the direct simulation Monte Carlo (DSMC) method. A micro/meso-scale pump, the Knudsen compressor, was chosen to illustrate the importance of controlling working gas temperature in thermal creep-driven flows. Gas pressure and temperature variations, through several Knudsen compressor stage configurations, were studied to determine the most advantageous flow phenomena for the efficient operation of Knudsen compressors.

  20. Charge collection in Si detectors irradiated in situ at superfluid helium temperature

    Energy Technology Data Exchange (ETDEWEB)

    Verbitskaya, Elena, E-mail: elena.verbitskaya@cern.ch [Ioffe Institute, 26 Politekhnicheskaya str., St. Petersburg 194021 (Russian Federation); Eremin, Vladimir; Zabrodskii, Andrei [Ioffe Institute, 26 Politekhnicheskaya str., St. Petersburg 194021 (Russian Federation); Dehning, Bernd; Kurfürst, Christoph; Sapinski, Mariusz; Bartosik, Marcin R. [CERN, CH-1211, Geneva 23 (Switzerland); Egorov, Nicolai [Research Institute of Material Science and Technology, 4 Passage 4806, Moscow, Zelenograd 124460 (Russian Federation); Härkönen, Jaakko [Helsinki Institute of Physics, P.O.Box 64 (Gustaf Hallströmin katu 2) FI-00014 University of Helsinki (Finland)

    2015-10-01

    Silicon and diamond detectors operated in a superfluid helium bath are currently being considered for the upgrade of the LHC beam loss monitoring system. The detectors would be installed in immediate proximity of the superconducting coils of the triplet magnets. We present here the results of the in situ irradiation test for silicon detectors using 23 GeV protons while keeping the detectors at a temperature of 1.9 K. Red laser (630 nm) Transient Current Technique and DC current measurements were used to study the pulse response and collected charge for silicon detectors irradiated to a maximum radiation fluence of 1×10{sup 16} p/cm{sup 2}. The dependence between collected charge and irradiation fluence was parameterized using the Hecht equation and assumption of a uniform electric field distribution. The collected charge was found to degrade with particle fluence for both bias polarities. We observed that the main factor responsible for this degradation was related to trapping of holes on the donor-type radiation-induced defects. In contrast to expectations, along with formation of donors, acceptor-type defects (electron traps) are introduced into the silicon bulk. This suggests that the current models describing charge collection in irradiated silicon detectors require an extension for taking into account trapping at low temperatures with a contribution of shallow levels. New in situ irradiation tests are needed and planned now to extend statistics of the results and gain a deeper insight into the physics of low temperature detector operation in harsh radiation environment. - Highlights: • Si detectors irradiated in situ at 1.9 K by 23 GeV protons are further studied. • Trapping parameters are derived from the fits of collected charge vs. fluence data. • Acceptor-type defects are likely to be induced along with donor-type ones. • Trapping of holes has a dominating effect on the collected charge degradation. • New tests are planned to gain deeper insight

  1. A new contact electric resistance technique for in-situ measurement of the electric resistance of surface films on metals in electrolytes at high temperatures and pressures

    International Nuclear Information System (INIS)

    Saario, T.; Marichev, V.A.

    1993-01-01

    Surface films play a major role in corrosion assisted cracking. A new Contact Electric Resistance (CER) method has been recently developed for in situ measurement of the electric resistance of surface films. The method has been upgraded for high temperature high pressure application. The technique can be used for any electrically conductive material in any environment including liquid, gas or vacuum. The technique has been used to determine in situ the electric resistance of films on metals during adsorption of water and anions, formation and destruction of oxides and hydrides, electroplating of metals and to study the electric resistance of films on semiconductors. The resolution of the CER technique is 10 -9 Ω, which corresponds to about 0.03 monolayers of deposited copper during electrochemical deposition Cu/Cu 2+ . Electric resistance data can be measured with a frequency of the order of one hertz, which enables one to follow in situ the kinetics of surface film related processes. The kinetics of these processes and their dependence on the environment, temperature, pH and electrochemical potential can be investigated

  2. Comparison of Land Skin Temperature from a Land Model, Remote Sensing, and In-situ Measurement

    Science.gov (United States)

    Wang, Aihui; Barlage, Michael; Zeng, Xubin; Draper, Clara Sophie

    2014-01-01

    Land skin temperature (Ts) is an important parameter in the energy exchange between the land surface and atmosphere. Here hourly Ts from the Community Land Model Version 4.0, MODIS satellite observations, and in-situ observations in 2003 were compared. Compared with the in-situ observations over four semi-arid stations, both MODIS and modeled Ts show negative biases, but MODIS shows an overall better performance. Global distribution of differences between MODIS and modeled Ts shows diurnal, seasonal, and spatial variations. Over sparsely vegetated areas, the model Ts is generally lower than the MODIS observed Ts during the daytime, while the situation is opposite at nighttime. The revision of roughness length for heat and the constraint of minimum friction velocity from Zeng et al. [2012] bring the modeled Ts closer to MODIS during the day, and have little effect on Ts at night. Five factors contributing to the Ts differences between the model and MODIS are identified, including the difficulty in properly accounting for cloud cover information at the appropriate temporal and spatial resolutions, and uncertainties in surface energy balance computation, atmospheric forcing data, surface emissivity, and MODIS Ts data. These findings have implications for the cross-evaluation of modeled and remotely sensed Ts, as well as the data assimilation of Ts observations into Earth system models.

  3. Contribution to high-temperature chromatography and high-temperature-gas-chromatography-mass spectrometry of lipids

    International Nuclear Information System (INIS)

    Aichholz, R.

    1998-04-01

    This thesis describes the use of high temperature gas chromatography for the investigation of unusual triacylglycerols, cyanolipids and bees waxes. The used glass capillary columns were pretreated and coated with tailor made synthesized high temperature stable polysiloxane phases. The selective separation properties of the individual columns were tested with a synthetic lipid mixture. Suitable derivatization procedures for the gaschromatographic analyses of neutral lipids, containing multiple bonds as well as hydroxy-, epoxy-, and carboxyl groups, were developed and optimized. Therefore conjugated olefinic-, conjugated olefinic-acetylenic-, hydroxy-, epoxy-, and conjugated olefinic keto triacylglycerols in miscellaneous plant seed oils as well as hydroxy monoesters, diesters and hydroxy diesters in bees waxes could be analysed directly with high temperature gas chromatography for the first time. In order to elucidate the structures of separated lipid compounds, high temperature gas chromatography was coupled to mass spectrometry and tandem mass spectrometry, respectively. Comparable analytical systems are hitherto not commercial available. Therefore instrumental prerequisites for a comprehensive and detailed analysis of seed oils and bees waxes were established. In GC/MS commonly two ionization methods are used, electron impact ionization and chemical ionization. For the analysis of lipids the first is of limited use only. Due to intensive fragmentation only weak molecular ions are observed. In contrast, the chemical ionization yields in better results. Dominant quasi molecular ions enable an unambiguous determination of the molecular weight. Moreover, characteristic fragment ions provide important indications of certain structural features of the examined compounds. Nevertheless, in some cases the chromatographic resolution was insufficient in order to separate all compounds present in natural lipid mixtures. Owing to the selected detection with mass spectrometry

  4. Very-high-temperature gas reactor environmental impacts assessment

    International Nuclear Information System (INIS)

    Baumann, C.D.; Barton, C.J.; Compere, E.L.; Row, T.H.

    1977-08-01

    The operation of a Very High Temperature Reactor (VHTR), a slightly modified General Atomic type High Temperature Gas-Cooled Reactor (HTGR) with 1600 F primary coolant, as a source of process heat for the 1400 0 F steam-methanation reformer step in a hydrogen producing plant (via hydrogasification of coal liquids) was examined. It was found that: (a) from the viewpoint of product contamination by fission and activation products, an Intermediate Heat Exchanger (IHX) is probably not necessary; and (b) long term steam corrosion of the core support posts may require increasing their diameter (a relatively minor design adjustment). However, the hydrogen contaminant in the primary coolant which permeates the reformer may reduce steam corrosion but may produce other problems which have not as yet been resolved. An IHX in parallel with both the reformer and steam generator would solve these problems, but probably at greater cost than that of increasing the size of the core support posts. It is recommended that this corrosion problem be examined in more detail, especially by investigating the performance of current fossil fuel heated reformers in industry. Detailed safety analysis of the VHTR would be required to establish definitely whether the IHX can be eliminated. Water and hydrogen ingress into the reactor system are potential problems which can be alleviated by an IHX. These problems will require analysis, research and development within the program required for development of the VHTR

  5. Recent developments in high temperature coatings for gas turbine airfoils

    Science.gov (United States)

    Goward, G. W.

    1983-01-01

    The importance of coatings for hot section airfoils has increased with the drive for more cost-effective use of fuel in a wide variety of gas turbine engines. Minor additions of silicon have been found to appreciably increase the oxidation resistance of plasma-sprayed NiCoCrAlY coatings on a single crystal nickel-base superalloy. Increasing the chromium content of MCrAlY coatings substantially increases the resistance to acidic (Na2SO4-SO3) hot corrosion at temperatures of about 1300 F (704 C) but gives no significant improvement beyond contemporary coatings in the range of 1600 F (871 C). Surface enrichment of MCrAlY coatings with silicon also gives large increases in resistance to acidic hot corrosion in the 1300 F region. The resistance to the thermal stress-induced spalling of zirconia-based thermal barrier coatings has been improved by lowering coating stresses with segmented structures and by controlling the substrate temperature during coating fabrication.

  6. In-situ neutron diffraction measurements of temperature and stresses during friction stir welding of 6061-T6 aluminum alloy

    International Nuclear Information System (INIS)

    Woo, Wan Chuck; Feng, Zhili; Wang, Xun-Li; Brown, D.W.; Clausen, B.; An, Ke; Choo, Hahn; Hubbard, Camden R.; David, Stan A.

    2007-01-01

    The evolution of temperature and thermal stresses during friction stir welding of Al6061-T6 was investigated by means of in-situ, time-resolved neutron diffraction technique. A method is developed to deconvolute the temperature and stress from the lattice spacing changes measured by neutron diffraction. The deep penetration capability of neutrons made it possible for the first time to obtain the temperature and thermal stresses inside a friction stir weld

  7. Abnormal gas-liquid-solid phase transition behaviour of water observed with in situ environmental SEM.

    Science.gov (United States)

    Chen, Xin; Shu, Jiapei; Chen, Qing

    2017-04-24

    Gas-liquid-solid phase transition behaviour of water is studied with environmental scanning electron microscopy for the first time. Abnormal phenomena are observed. At a fixed pressure of 450 Pa, with the temperature set to -7 °C, direct desublimation happens, and ice grows continuously along the substrate surface. At 550 Pa, although ice is the stable phase according to the phase diagram, metastable liquid droplets first nucleate and grow to ~100-200 μm sizes. Ice crystals nucleate within the large sized droplets, grow up and fill up the droplets. Later, the ice crystals grow continuously through desublimation. At 600 Pa, the metastable liquid grows quickly, with some ice nuclei floating in it, and the liquid-solid coexistence state exists for a long time. By lowering the vapour pressure and/or increasing the substrate temperature, ice sublimates into vapour phase, and especially, the remaining ice forms a porous structure due to preferential sublimation in the concave regions, which can be explained with surface tension effect. Interestingly, although it should be forbidden for ice to transform into liquid phase when the temperature is well below 0 °C, liquid like droplets form during the ice sublimation process, which is attributed to the surface tension effect and the quasiliquid layers.

  8. Parametric studies on different gas turbine cycles for a high temperature gas-cooled reactor

    International Nuclear Information System (INIS)

    Wang Jie; Gu Yihua

    2005-01-01

    The high temperature gas-cooled reactor (HTGR) coupled with turbine cycle is considered as one of the leading candidates for future nuclear power plants. In this paper, the various types of HTGR gas turbine cycles are concluded as three typical cycles of direct cycle, closed indirect cycle and open indirect cycle. Furthermore they are theoretically converted to three Brayton cycles of helium, nitrogen and air. Those three types of Brayton cycles are thermodynamically analyzed and optimized. The results show that the variety of gas affects the cycle pressure ratio more significantly than other cycle parameters, however, the optimized cycle efficiencies of the three Brayton cycles are almost the same. In addition, the turbomachines which are required for the three optimized Brayton cycles are aerodynamically analyzed and compared and their fundamental characteristics are obtained. Helium turbocompressor has lower stage pressure ratio and more stage number than those for nitrogen and air machines, while helium and nitrogen turbocompressors have shorter blade length than that for air machine

  9. Brightness temperature simulation of snow cover based on snow grain size evolution using in situ data

    Science.gov (United States)

    Wu, Lili; Li, Xiaofeng; Zhao, Kai; Zheng, Xingming; Jiang, Tao

    2016-07-01

    Snow depth parameter inversion from passive microwave remote sensing is of great significance to hydrological process and climate systems. The Helsinki University of Technology (HUT) model is a commonly used snow emission model. Snow grain size (SGS) is one of the important input parameters, but SGS is difficult to obtain in broad areas. The time series of SGS are first evolved by an SGS evolution model (Jordan 91) using in situ data. A good linear relationship between the effective SGS in HUT and the evolution SGS was found. Then brightness temperature simulations are performed based on the effective SGS and evolution SGS. The results showed that the biases of the simulated brightness temperatures based on the effective SGS and evolution SGS were -6.5 and -3.6 K, respectively, for 18.7 GHz and -4.2 and -4.0 K for 36.5 GHz. Furthermore, the model is performed in six pixels with different land use/cover type in other areas. The results showed that the simulated brightness temperatures based on the evolution SGS were consistent with those from the satellite. Consequently, evolution SGS appears to be a simple method to obtain an appropriate SGS for the HUT model.

  10. In Situ Irradiation and Measurement of Triple Junction Solar Cells at Low Intensity, Low Temperature (LILT) Conditions

    Science.gov (United States)

    Harris, R.D.; Imaizumi, M.; Walters, R.J.; Lorentzen, J.R.; Messenger, S.R.; Tischler, J.G.; Ohshima, T.; Sato, S.; Sharps, P.R.; Fatemi, N.S.

    2008-01-01

    The performance of triple junction InGaP/(In)GaAs/Ge space solar cells was studied following high energy electron irradiation at low temperature. Cell characterization was carried out in situ at the irradiation temperature while using low intensity illumination, and, as such, these conditions reflect those found for deep space, solar powered missions that are far from the sun. Cell characterization consisted of I-V measurements and quantum efficiency measurements. The low temperature irradiations caused substantial degradation that differs in some ways from that seen after room temperature irradiations. The short circuit current degrades more at low temperature while the open circuit voltage degrades more at room temperature. A room temperature anneal after the low temperature irradiation produced a substantial recovery in the degradation. Following irradiation at both temperatures and an extended room temperature anneal, quantum efficiency measurement suggests that the bulk of the remaining damage is in the (In)GaAs sub-cell

  11. Enhanced spectroscopic gas sensors using in-situ grown carbon nanotubes

    Energy Technology Data Exchange (ETDEWEB)

    De Luca, A.; Cole, M. T.; Milne, W. I. [Department of Engineering, University of Cambridge, Cambridge CB3 0FA (United Kingdom); Hopper, R. H.; Boual, S.; Ali, S. Z. [Cambridge CMOS Sensors Ltd., Deanland House, 160 Cowley Road, Cambridge CB4 0DL (United Kingdom); Warner, J. H.; Robertson, A. R. [Department of Materials, University of Oxford, Oxford OX1 3PH (United Kingdom); Udrea, F. [Department of Engineering, University of Cambridge, Cambridge CB3 0FA (United Kingdom); Cambridge CMOS Sensors Ltd., Deanland House, 160 Cowley Road, Cambridge CB4 0DL (United Kingdom); Gardner, J. W. [School of Engineering, University of Warwick, Coventry CV4 7AL (United Kingdom)

    2015-05-11

    In this letter, we present a fully complementary-metal-oxide-semiconductor (CMOS) compatible microelectromechanical system thermopile infrared (IR) detector employing vertically aligned multi-walled carbon nanotubes (CNT) as an advanced nano-engineered radiation absorbing material. The detector was fabricated using a commercial silicon-on-insulator (SOI) process with tungsten metallization, comprising a silicon thermopile and a tungsten resistive micro-heater, both embedded within a dielectric membrane formed by a deep-reactive ion etch following CMOS processing. In-situ CNT growth on the device was achieved by direct thermal chemical vapour deposition using the integrated micro-heater as a micro-reactor. The growth of the CNT absorption layer was verified through scanning electron microscopy, transmission electron microscopy, and Raman spectroscopy. The functional effects of the nanostructured ad-layer were assessed by comparing CNT-coated thermopiles to uncoated thermopiles. Fourier transform IR spectroscopy showed that the radiation absorbing properties of the CNT adlayer significantly enhanced the absorptivity, compared with the uncoated thermopile, across the IR spectrum (3 μm–15.5 μm). This led to a four-fold amplification of the detected infrared signal (4.26 μm) in a CO{sub 2} non-dispersive-IR gas sensor system. The presence of the CNT layer was shown not to degrade the robustness of the uncoated devices, whilst the 50% modulation depth of the detector was only marginally reduced by 1.5 Hz. Moreover, we find that the 50% normalized absorption angular profile is subsequently more collimated by 8°. Our results demonstrate the viability of a CNT-based SOI CMOS IR sensor for low cost air quality monitoring.

  12. Corrosion behaviour of high temperature alloys in the cooling gas of high temperature reactors

    International Nuclear Information System (INIS)

    Quadakkers, W.J.; Schuster, H.

    1989-01-01

    The reactive impurities in the primary cooling helium of advanced high temperature gas cooled reactors (HTGR) can cause oxidation, carburization or decarburization of the heat exchanging metallic components. By studies of the fundamental aspects of the corrosion mechanisms it became possible to define operating conditions under which the metallic construction materials show, from the viewpoint of technical application, acceptable corrosion behaviour. By extensive test programmes with exposure times of up to 30,000 hours, a data base has been obtained which allows a reliable extrapolation of the corrosion effects up to the envisaged service lives of the heat exchanging components. (author). 6 refs, 7 figs

  13. Temperature Control of Gas Chromatograph Based on Switched Delayed System Techniques

    Directory of Open Access Journals (Sweden)

    Xiao-Liang Wang

    2014-01-01

    Full Text Available We address the temperature control problem of the gas chromatograph. We model the temperature control system of the gas chromatograph into a switched delayed system and analyze the stability by common Lyapunov functional technique. The PI controller parameters can be given based on the proposed linear matrix inequalities (LMIs condition and the designed controller can make the temperature of gas chromatograph track the reference signal asymptotically. An experiment is given to illustrate the effectiveness of the stability criterion.

  14. Gas injection to inhibit migration during an in situ heat treatment process

    Science.gov (United States)

    Kuhlman, Myron Ira; Vinegar; Harold J.; Baker, Ralph Sterman; Heron, Goren

    2010-11-30

    Methods of treating a subsurface formation are described herein. Methods for treating a subsurface treatment area in a formation may include introducing a fluid into the formation from a plurality of wells offset from a treatment area of an in situ heat treatment process to inhibit outward migration of formation fluid from the in situ heat treatment process.

  15. The Determination of Pesticidal and Non-Pesticidal Organotin Compounds by in situ Ethylation and Capillary Gas Chromatography with Pulsed Flame Photometric Detection

    Science.gov (United States)

    The concurrent determination of pesticidal and non-pesticidal organotin compounds in several water matrices, using a simultaneous in situ ethylation and liquid-liquid extraction followed by splitless injection mode capillary gas chromatography with pulsed flame photometric detect...

  16. The Determination of Pesticidal and Non-Pesticidal Organotin Compounds in Water Matrices by in situ Ethylation and Gas Chromatography with Pulsed Flame Photometric Detection

    Science.gov (United States)

    The concurrent determination of pesticidal and non-pesticidal organotin compounds in several water matrices, using a simultaneous in situ ethylation and liquid-liquid extraction followed by splitless injection mode capillary gas chromatography with pulsed flame photometric detect...

  17. Determining of Degradation and Digestion Coefficients of Canola meal Using of In situ and Gas production Techniques

    Directory of Open Access Journals (Sweden)

    Younes Tahmazi

    2015-04-01

    Full Text Available This study was carried out to the determination of nutritive value of canola meal using naylon bag and cumulative gas production techniques in Gizel sheep. Tow fistulated Gizel sheep with average BW 45±2 kg used in a complete randomized design. The cumulative gas production was measured at 2, 4, 6, 8, 12, 16, 24, 36 and 48 h and ruminal DM and CP disappearance were measured up to 96 h. Coefficients of soluble CP degradation of canola meal (A, canola meal treated with 0.5% urea (B and canola meal treated with micro wave (C were 4.74, 15.81 and 15%, and for fermentable portion were 31.05, 39.62 and 65.55%, respectively. The cumulative gas production of soluble and insoluble portions (a+b were 252.13, 213.57 and 240.88 ml/g DM. Metabolizable protein of treatments A, B and C were 283.11, 329.33 and 284.39 g/kg DM, that were not significantly different. The relationship between dry matter and cumulative gas production values for treatments obtained about 0.958, 0.976 and 0.932 and this parameter for crude protein and cumulative gas production achieved 0.987, 0.994 and 0.989, respectively. High correlation between in situ and cumulative gas production techniques indicated that digestibility values can be predicted from cumulative gas production data.

  18. Improved design for a low temperature scanning tunneling microscope with an in situ tip treatment stage.

    Science.gov (United States)

    Kim, J-J; Joo, S H; Lee, K S; Yoo, J H; Park, M S; Kwak, J S; Lee, Jinho

    2017-04-01

    The Low Temperature Scanning Tunneling Microscope (LT-STM) is an extremely valuable tool not only in surface science but also in condensed matter physics. For years, numerous new ideas have been adopted to perfect LT-STM performances-Ultra-Low Vibration (ULV) laboratory and the rigid STM head design are among them. Here, we present three improvements for the design of the ULV laboratory and the LT-STM: tip treatment stage, sample cleaving stage, and vibration isolation system. The improved tip treatment stage enables us to perform field emission for the purpose of tip treatment in situ without exchanging samples, while our enhanced sample cleaving stage allows us to cleave samples at low temperature in a vacuum without optical access by a simple pressing motion. Our newly designed vibration isolation system provides efficient space usage while maintaining vibration isolation capability. These improvements enhance the quality of spectroscopic imaging experiments that can last for many days and provide increased data yield, which we expect can be indispensable elements in future LT-STM designs.

  19. In situ observation of carbon nanotube layer growth on microbolometers with substrates at ambient temperature

    Science.gov (United States)

    Svatoš, Vojtěch; Gablech, Imrich; Ilic, B. Robert; Pekárek, Jan; Neužil, Pavel

    2018-03-01

    Carbon nanotubes (CNTs) have near unity infrared (IR) absorption efficiency, making them extremely attractive for IR imaging devices. Since CNT growth occurs at elevated temperatures, the integration of CNTs with IR imaging devices is challenging and has not yet been achieved. Here, we show a strategy for implementing CNTs as IR absorbers using differential heating of thermally isolated microbolometer membranes in a C2H2 environment. During the process, CNTs were catalytically grown on the surface of a locally heated membrane, while the substrate was maintained at an ambient temperature. CNT growth was monitored in situ in real time using optical microscopy. During growth, we measured the intensity of light emission and the reflected light from the heated microbolometer. Our measurements of bolometer performance show that the CNT layer on the surface of the microbolometer membrane increases the IR response by a factor of (2.3 ± 0.1) (mean ± one standard deviation of the least-squares fit parameters). This work opens the door to integrating near unity IR absorption, CNT-based, IR absorbers with hybrid complementary metal-oxide-semiconductor focal plane array architectures.

  20. Structural instabilities of high temperature alloys and their use in advanced high temperature gas cooled reactors

    International Nuclear Information System (INIS)

    Schuster, H.; Ennis, P.J.; Nickel, H.; Czyrska-Filemonowicz, A.

    1989-01-01

    High-temperature, iron-nickel and nickel based alloys are the candidate heat exchanger materials for advanced high temperature gas-cooled reactors supplying process heat for coal gasification, where operation temperatures can reach 850-950 deg. C and service lives of more than 100,000 h are necessary. In the present paper, typical examples of structural changes which occur in two representative alloys (Alloy 800 H, Fe-32Ni-20Cr and Alloy 617, Ni-22Cr-12Co-9Mo-1Al) during high temperature exposure will be given and the effects on the creep rupture properties discussed. At service temperatures, precipitation of carbides occurs which has a significant effect on the creep behaviour, especially in the early stages of creep when the precipitate particles are very fine. During coarsening of the carbides, carbides at grain boundaries restrict grain boundary sliding which retards the development of creep damage. In the service environments, enhanced carbide precipitation may occur due to the ingress of carbon from the environment (carburization). Although the creep rate is not adversely affected, the ductility of the carburized material at low and intermediate temperatures is very low. During simulated service exposures, the formation of surface corrosion scales, the precipitation of carbides and the formation of internal oxides below the surface leads to depletion of the matrix in the alloying elements involved in the corrosion processes. In thin-walled tubes the depletion of Cr due to Cr 2 O 3 formation on the surface can lead to a loss of creep strength. An additional depletion effect resulting from environmental-metal reactions is the loss of carbon (decarburization) which may occur in specific environments. The compositions of the cooling gases which decarburize the material have been determined; they are to be avoided during reactor operation

  1. The Use of Satellite Data to Relate Waterbody Surface Area and Temperature to Greenhouse Gas Emissions Across a Subarctic Landscape

    Science.gov (United States)

    Herrick, C.; Palace, M. W.; Wik, M.; Burke, S. A.; Varner, R. K.

    2017-12-01

    High latitude lakes and ponds are significant sources of methane (CH4) and carbon dioxide (CO2) emission. Increased near-surface air temperature has linked these water bodies to large increases in methane emissions due to longer ice-free seasons, impacting climate change and further changing air temperature as a feedback mechanism. The impacts of changes in lake surface temperatures cannot be assessed until we know more about the baseline mechanistic biogeochemical controls that influence these emissions. Using a combination of image-based atmospheric corrections and image fusion models, thermal data from Landsat and MODIS satellites were used to characterize the temperature regimes of artic lakes in northern Sweden. This analysis provides insight into the temporal attributes of individual lakes in regard to temperature shifts and variability, as well as provides a rich temporal dataset where in situ temperature data is unavailable. Field-based measurements of temperature and associated methane release were used for calibration and correlation. This enabled the creation of emissions estimates over the broader pan-arctic landscape, including inter-seasonal and inter-annual variabilities. The result is a multi-year snapshot of temperature and emissions, allowing for future estimates of greenhouse gas emissions.

  2. High-temperature CO / HC gas sensors to optimize firewood combustion in low-power fireplaces

    Directory of Open Access Journals (Sweden)

    B. Ojha

    2017-06-01

    Full Text Available In order to optimize firewood combustion in low-power firewood-fuelled fireplaces, a novel combustion airstream control concept based on the signals of in situ sensors for combustion temperature, residual oxygen concentration and residual un-combusted or partly combusted pyrolysis gas components (CO and HC has been introduced. A comparison of firing experiments with hand-driven and automated airstream-controlled furnaces of the same type showed that the average CO emissions in the high-temperature phase of the batch combustion can be reduced by about 80 % with the new control concept. Further, the performance of different types of high-temperature CO / HC sensors (mixed-potential and metal oxide types, with reference to simultaneous exhaust gas analysis by a high-temperature FTIR analysis system, was investigated over 20 batch firing experiments (∼ 80 h. The distinctive sensing behaviour with respect to the characteristically varying flue gas composition over a batch firing process is discussed. The calculation of the Pearson correlation coefficients reveals that mixed-potential sensor signals correlate more with CO and CH4; however, different metal oxide sensitive layers correlate with different gas species: 1 % Pt / SnO2 designates the presence of CO and 2 % ZnO / SnO2 designates the presence of hydrocarbons. In the case of a TGS823 sensor element, there was no specific correlation with one of the flue gas components observed. The stability of the sensor signals was evaluated through repeated exposure to mixtures of CO, N2 and synthetic air after certain numbers of firing experiments and exhibited diverse long-term signal instabilities.

  3. Use of thorium for high temperature gas-cooled reactors

    Energy Technology Data Exchange (ETDEWEB)

    Guimarães, Cláudio Q., E-mail: claudio_guimaraes@usp.br [Universidade de São Paulo (USP), SP (Brazil). Instituto de Física; Stefani, Giovanni L. de, E-mail: giovanni.stefani@ipen.br [Instituto de Pesquisas Energéticas e Nucleares (IPEN/CNEN-SP), São Paulo, SP (Brazil); Santos, Thiago A. dos, E-mail: thiago.santos@ufabc.edu.br [Universidade Federal do ABC (UFABC), Santo André, SP (Brazil)

    2017-07-01

    The HTGR ( High Temperature Gas-cooled Reactor) is a 4{sup th} generation nuclear reactor and is fuelled by a mixture of graphite and fuel-bearing microspheres. There are two competitive designs of this reactor type: The German “pebble bed” mode, which is a system that uses spherical fuel elements, containing a graphite-and-fuel mixture coated in a graphite shell; and the American version, whose fuel is loaded into precisely located graphite hexagonal prisms that interlock to create the core of the vessel. In both variants, the coolant consists of helium pressurised. The HTGR system operates most efficiently with the thorium fuel cycle, however, so relatively little development has been carried out in this country on that cycle for HTGRs. In the Nuclear Engineering Centre of IPEN (Instituto de Pesquisas Energéticas e Nucleares), a study group is being formed linked to thorium reactors, whose proposal is to investigate reactors using thorium for {sup 233}U production and rejects burning. The present work intends to show the use of thorium in HTGRs, their advantages and disadvantages and its feasibility. (author)

  4. Inherently safe high temperature gas-cooled reactor

    International Nuclear Information System (INIS)

    Yamada, Masao; Hayakawa, Hitoshi

    1987-01-01

    It is recognized in general that High Temperature Gas-cooled Reactors have remarkable characteristics in inherent safety and it is well known that credits of the time margin have been admitted for accident evaluation in the licensing of the currently operating prototype HTGRs (300 MWe class). Recently, more inherently safe HTGRs are being developed in various countries and drawing attention on their possibility for urban siting. The inherent safety characteristics of these HTRs differ each other depending on their design philosophy and on the features of the components/structures which constitute the plant. At first, the specific features/characteristics of the elemental components/structures of the HTRs are explained one by one and then the overall safety features/characteristics of these HTR plants are explained in connection with their design philosophy and combination of the elemental features. Taking the KWU/Interatom Modular Reactor System as an example, the particular design philosophy and safety characteristics of the inherently safe HTR are explained with a result of preliminary evaluation on the possibility of siting close to densely populated area. (author)

  5. In situ electron beam irradiated rapid growth of bismuth nanoparticles in bismuth-based glass dielectrics at room temperature

    International Nuclear Information System (INIS)

    Singh, Shiv Prakash; Karmakar, Basudeb

    2011-01-01

    In this study, in situ control growth of bismuth nanoparticles (Bi 0 NPs) was demonstrated in bismuth-based glass dielectrics under an electron beam (EB) irradiation at room temperature. The effects of EB irradiation were investigated in situ using transmission electron microscopy (TEM), selected-area electron diffraction and high-resolution transmission electron microscopy. The EB irradiation for 2–8 min enhanced the construction of bismuth nanoparticles with a rhombohedral structure and diameter of 4–9 nm. The average particle size was found to increase with the irradiation time. Bismuth metal has a melting point of 271 °C and this low melting temperature makes easy the progress of energy induced structural changes during in situ TEM observations. This is a very useful technique in nano-patterning for integrated optics and other applications.

  6. An atmospheric pressure high-temperature laminar flow reactor for investigation of combustion and related gas phase reaction systems

    Energy Technology Data Exchange (ETDEWEB)

    Oßwald, Patrick; Köhler, Markus [Institute of Combustion Technology, German Aerospace Center (DLR), Pfaffenwaldring 38-40, D-70569 Stuttgart (Germany)

    2015-10-15

    A new high-temperature flow reactor experiment utilizing the powerful molecular beam mass spectrometry (MBMS) technique for detailed observation of gas phase kinetics in reacting flows is presented. The reactor design provides a consequent extension of the experimental portfolio of validation experiments for combustion reaction kinetics. Temperatures up to 1800 K are applicable by three individually controlled temperature zones with this atmospheric pressure flow reactor. Detailed speciation data are obtained using the sensitive MBMS technique, providing in situ access to almost all chemical species involved in the combustion process, including highly reactive species such as radicals. Strategies for quantifying the experimental data are presented alongside a careful analysis of the characterization of the experimental boundary conditions to enable precise numeric reproduction of the experimental results. The general capabilities of this new analytical tool for the investigation of reacting flows are demonstrated for a selected range of conditions, fuels, and applications. A detailed dataset for the well-known gaseous fuels, methane and ethylene, is provided and used to verify the experimental approach. Furthermore, application for liquid fuels and fuel components important for technical combustors like gas turbines and engines is demonstrated. Besides the detailed investigation of novel fuels and fuel components, the wide range of operation conditions gives access to extended combustion topics, such as super rich conditions at high temperature important for gasification processes, or the peroxy chemistry governing the low temperature oxidation regime. These demonstrations are accompanied by a first kinetic modeling approach, examining the opportunities for model validation purposes.

  7. An atmospheric pressure high-temperature laminar flow reactor for investigation of combustion and related gas phase reaction systems.

    Science.gov (United States)

    Oßwald, Patrick; Köhler, Markus

    2015-10-01

    A new high-temperature flow reactor experiment utilizing the powerful molecular beam mass spectrometry (MBMS) technique for detailed observation of gas phase kinetics in reacting flows is presented. The reactor design provides a consequent extension of the experimental portfolio of validation experiments for combustion reaction kinetics. Temperatures up to 1800 K are applicable by three individually controlled temperature zones with this atmospheric pressure flow reactor. Detailed speciation data are obtained using the sensitive MBMS technique, providing in situ access to almost all chemical species involved in the combustion process, including highly reactive species such as radicals. Strategies for quantifying the experimental data are presented alongside a careful analysis of the characterization of the experimental boundary conditions to enable precise numeric reproduction of the experimental results. The general capabilities of this new analytical tool for the investigation of reacting flows are demonstrated for a selected range of conditions, fuels, and applications. A detailed dataset for the well-known gaseous fuels, methane and ethylene, is provided and used to verify the experimental approach. Furthermore, application for liquid fuels and fuel components important for technical combustors like gas turbines and engines is demonstrated. Besides the detailed investigation of novel fuels and fuel components, the wide range of operation conditions gives access to extended combustion topics, such as super rich conditions at high temperature important for gasification processes, or the peroxy chemistry governing the low temperature oxidation regime. These demonstrations are accompanied by a first kinetic modeling approach, examining the opportunities for model validation purposes.

  8. Infrared temperature and gas measurements at the Haderslev power and heat plan[Denmark]; Infraroede temperatur- og gasmaelinger Haderslev Kraftvarmevaerk

    Energy Technology Data Exchange (ETDEWEB)

    Clausen, Soennik

    2007-04-15

    Report describe results from a two week measurement campaign at Haderslev Kraftvarmevaerk in 2006 as a part of PSO-project 5727 'On-line optimization of waste incinerators'. Non-contact gas temperature and gas composition was measured simultaneously with a FTIR spectrometer coupled to a water-cooled fiber-optic probe. Gas temperature and H{sub 2}O, CO{sub 2}, CO, C{sub x}H{sub y} and HCl concentrations was extracted from measured spectra of emitted thermal radiation from gas slab over a 25 cm path. Measurements where performed in different positions to obtain a overview of flow behavior and conditions during stable operation and during a step in operation conditions, e.g. changing combustion air flows. Furthermore, surface temperature of grate was monitored with a thermal camera and a cross stack reference measurement on hot outlet gas was performed with a FTIR spectrometer. (au)

  9. High Temperature Gas-to-Gas Heat Exchanger Based on a Solid Intermediate Medium

    Directory of Open Access Journals (Sweden)

    R. Amirante

    2014-04-01

    Full Text Available This paper proposes the design of an innovative high temperature gas-to-gas heat exchanger based on solid particles as intermediate medium, with application in medium and large scale externally fired combined power plants fed by alternative and dirty fuels, such as biomass and coal. An optimization procedure, performed by means of a genetic algorithm combined with computational fluid dynamics (CFD analysis, is employed for the design of the heat exchanger: the goal is the minimization of its size for an assigned heat exchanger efficiency. Two cases, corresponding to efficiencies equal to 80% and 90%, are considered. The scientific and technical difficulties for the realization of the heat exchanger are also faced up; in particular, this work focuses on the development both of a pressurization device, which is needed to move the solid particles within the heat exchanger, and of a pneumatic conveyor, which is required to deliver back the particles from the bottom to the top of the plant in order to realize a continuous operation mode. An analytical approach and a thorough experimental campaign are proposed to analyze the proposed systems and to evaluate the associated energy losses.

  10. In situ laser-induced breakdown spectroscopy measurements of chemical compositions in stainless steels during tungsten inert gas welding

    Science.gov (United States)

    Taparli, Ugur Alp; Jacobsen, Lars; Griesche, Axel; Michalik, Katarzyna; Mory, David; Kannengiesser, Thomas

    2018-01-01

    A laser-induced breakdown spectroscopy (LIBS) system was combined with a bead-on-plate Tungsten Inert Gas (TIG) welding process for the in situ measurement of chemical compositions in austenitic stainless steels during welding. Monitoring the weld pool's chemical composition allows governing the weld pool solidification behavior, and thus enables the reduction of susceptibility to weld defects. Conventional inspection methods for weld seams (e.g. ultrasonic inspection) cannot be performed during the welding process. The analysis system also allows in situ study of the correlation between the occurrence of weld defects and changes in the chemical composition in the weld pool or in the two-phase region where solid and liquid phase coexist. First experiments showed that both the shielding Ar gas and the welding arc plasma have a significant effect on the selected Cr II, Ni II and Mn II characteristic emissions, namely an artificial increase of intensity values via unspecific emission in the spectra. In situ investigations showed that this artificial intensity increase reached a maximum in presence of weld plume. Moreover, an explicit decay has been observed with the termination of the welding plume due to infrared radiation during sample cooling. Furthermore, LIBS can be used after welding to map element distribution. For austenitic stainless steels, Mn accumulations on both sides of the weld could be detected between the heat affected zone (HAZ) and the base material.

  11. Thermodynamics of gas-metal-slag equilibria for applications in in situ and ex situ vitrification melts

    International Nuclear Information System (INIS)

    Miller, R.L.; Reimann, G.A.

    1993-05-01

    An equilibrium thermodynamic model for melting mixed waste was evaluated using the STEPSOL computer code. STEPSOL uses free energy minimization techniques to predict equilibrium composition from input species and user selected species in the output. The model assumes equilibrium between gas, slag, and metallic phases. Input for the model was developed using compositional data from Pit 9 of the Subsurface Disposal Area at the Idaho National Engineering Laboratory. Thermodynamic data were primarily from compilations published by the US Government. The results of model evaluation indicate that the amount of plutonium chloride or plutonium oxyhydroxide that would be evaporated into the vapor phase would be minor. Relatively more uranium chloride and uranium oxyhydroxide would be vaporized. However, a hazards analysis was not part of the present task. Minor amounts of plutonium and uranium would be reduced to the metallic state, but these amounts should alloy with the iron-chromium-nickel metallic phase. The vast majority of the plutonium and uranium are in the slag phase as oxides. Results of the calculations show that silica and silicates dominate the products and that the system is very reducing. The major gases are carbon monoxide and hydrogen, with lesser amounts of carbon dioxide and water. High vapor pressure metals are considered but were not analyzed using STEPSOL. STEPSOL does not make predictions of distribution of species between phases

  12. Study on Method of Ultrasonic Gas Temperature Measure Based on FPGA

    Energy Technology Data Exchange (ETDEWEB)

    Wen, S H; Xu, F R [Institute of Electrical Engineering, Yanshan University, Qinhuangdao, 066004 (China)

    2006-10-15

    It is always a problem to measure instantaneous temperature of high-temperature and high-pressure gas. There is difficulty for the conventional method of measuring temperature to measure quickly and exactly, and the measuring precision is low, the ability of anti-jamming is bad, etc. So the article introduces a method of measuring burning gas temperature using ultrasonic based on Field-Programmable Gate Array (FPGA). The mathematic model of measuring temperature is built with the relation of velocity of ultrasonic transmitting and gas Kelvin in the ideal gas. The temperature can be figured out by measuring the difference of ultrasonic frequency {delta}f. FPGA is introduced and a high-precision data acquisition system based on digital phase-shift technology is designed. The feasibility of proposed above is confirmed more by measuring pressure of burning gas timely. Experimental result demonstrates that the error is less than 12.. and the precision is heightened to 0.8%.

  13. ATR-IR spectroscopic cell for in situ studies at solid-liquid interface at elevated temperatures and pressures

    NARCIS (Netherlands)

    Koichumanova, Kamila; Visan, Aura; Geerdink, Bert; Lammertink, Rob G.H.; Mojet, Barbara; Seshan, Kulathuiyer; Lefferts, Leonardus

    2017-01-01

    An in situ ATR-IR spectroscopic cell suitable for studies at solid-liquid interface is described including the design and experimental details in continuous flow mode at elevated temperatures (230 °C) and pressures (30 bar). The design parameters considered include the cell geometry, the procedure

  14. On the second-order temperature jump coefficient of a dilute gas

    Science.gov (United States)

    Radtke, Gregg A.; Hadjiconstantinou, N. G.; Takata, S.; Aoki, K.

    2012-09-01

    We use LVDSMC simulations to calculate the second-order temperature jump coefficient for a dilute gas whose temperature is governed by the Poisson equation with a constant forcing term. Both the hard sphere gas and the BGK model of the Boltzmann equation are considered. Our results show that the temperature jump coefficient is different from the well known linear and steady case where the temperature is governed by the homogeneous heat conduction (Laplace) equation.

  15. Biocatalytic hydroxylation of n-butane with in situ cofactor regeneration at low temperature and under normal pressure

    Directory of Open Access Journals (Sweden)

    Svenja Staudt

    2012-02-01

    Full Text Available The hydroxylation of n-alkanes, which proceeds in the presence of a P450-monooxygenase advantageously at temperatures significantly below room temperature, is described. In addition, an enzymatic hydroxylation of the “liquid gas” n-butane with in situ cofactor regeneration, which does not require high-pressure conditions, was developed. The resulting 2-butanol was obtained as the only regioisomer, at a product concentration of 0.16 g/L.

  16. Electrochemically Modulated Gas/Liquid Separation Technology for In Situ Resource Utilization Process Streams, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — In this phase I program MicroCell Technologies, LLC (MCT) proposes to demonstrate the feasibility of an electrochemically modulated phase separator for in situ...

  17. Miniature Gas Chromatograph Mass Spectrometer for In-Situ Resource Utilization, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — In situ resource utilization (ISRU) is essential for several of NASA's future flagship missions. Currently envisioned ISRU plants include production of oxygen from...

  18. CFD Analysis of the Fuel Temperature in High Temperature Gas-Cooled Reactors

    International Nuclear Information System (INIS)

    In, W. K.; Chun, T. H.; Lee, W. J.; Chang, J. H.

    2005-01-01

    High temperature gas-cooled reactors (HTGR) have received a renewed interest as potential sources for future energy needs, particularly for a hydrogen production. Among the HTGRs, the pebble bed reactor (PBR) and a prismatic modular reactor (PMR) are considered as the nuclear heat source in Korea's nuclear hydrogen development and demonstration project. PBR uses coated fuel particles embedded in spherical graphite fuel pebbles. The fuel pebbles flow down through the core during an operation. PMR uses graphite fuel blocks which contain cylindrical fuel compacts consisting of the fuel particles. The fuel blocks also contain coolant passages and locations for absorber and control material. The maximum fuel temperature in the core hot spot is one of the important design parameters for both PBR and PMR. The objective of this study is to predict the fuel temperature distributions in PBR and PMR using a computational fluid dynamics(CFD) code, CFX-5. The reference reactor designs used in this analysis are PBMR400 and GT-MHR600

  19. Electron temperature and density measurement of tungsten inert gas arcs with Ar-He shielding gas mixture

    Science.gov (United States)

    Kühn-Kauffeldt, M.; Marques, J.-L.; Forster, G.; Schein, J.

    2013-10-01

    The diagnostics of atmospheric welding plasma is a well-established technology. In most cases the measurements are limited to processes using pure shielding gas. However in many applications shielding gas is a mixture of various components including metal vapor in gas metal arc welding (GMAW). Shielding gas mixtures are intentionally used for tungsten inert gas (TIG) welding in order to improve the welding performance. For example adding Helium to Argon shielding gas allows the weld geometry and porosity to be influenced. Yet thermal plasmas produced with gas mixtures or metal vapor still require further experimental investigation. In this work coherent Thomson scattering is used to measure electron temperature and density in these plasmas, since this technique allows independent measurements of electron and ion temperature. Here thermal plasmas generated by a TIG process with 50% Argon and 50% Helium shielding gas mixture have been investigated. Electron temperature and density measured by coherent Thomson scattering have been compared to the results of spectroscopic measurements of the plasma density using Stark broadening of the 696.5 nm Argon spectral line. Further investigations of MIG processes using Thomson scattering technique are planned.

  20. Electron temperature and density measurement of tungsten inert gas arcs with Ar-He shielding gas mixture

    International Nuclear Information System (INIS)

    Kühn-Kauffeldt, M; Marques, J-L; Forster, G; Schein, J

    2013-01-01

    The diagnostics of atmospheric welding plasma is a well-established technology. In most cases the measurements are limited to processes using pure shielding gas. However in many applications shielding gas is a mixture of various components including metal vapor in gas metal arc welding (GMAW). Shielding gas mixtures are intentionally used for tungsten inert gas (TIG) welding in order to improve the welding performance. For example adding Helium to Argon shielding gas allows the weld geometry and porosity to be influenced. Yet thermal plasmas produced with gas mixtures or metal vapor still require further experimental investigation. In this work coherent Thomson scattering is used to measure electron temperature and density in these plasmas, since this technique allows independent measurements of electron and ion temperature. Here thermal plasmas generated by a TIG process with 50% Argon and 50% Helium shielding gas mixture have been investigated. Electron temperature and density measured by coherent Thomson scattering have been compared to the results of spectroscopic measurements of the plasma density using Stark broadening of the 696.5 nm Argon spectral line. Further investigations of MIG processes using Thomson scattering technique are planned

  1. Influence of Gas-Liquid Interface on Temperature Wave of Pulsating Heat Pipe

    Directory of Open Access Journals (Sweden)

    Ying Zhang

    2018-01-01

    Full Text Available The influence of the interface on the amplitude and phase of the temperature wave and the relationship between the attenuation of the temperature wave and the gas-liquid two-phase physical parameters are studied during the operation of the pulsating heat pipe. The numerical simulation shows that the existence of the phase interface changes the direction of the temperature gradient during the propagation of the temperature wave, which increases the additional “thermal resistance.” The relative size of the gas-liquid two-phase thermal conductivity affects the propagation direction of heat flow at phase interface directly. The blockage of the gas plug causes hysteresis in the phase of the temperature wave, the relative size of the gas-liquid two-phase temperature coefficient will gradually increase the phase of the temperature wave, and the time when the heat flow reaches the peak value is also advanced. The attenuation of the temperature wave is almost irrelevant to the absolute value of the density, heat capacity, and thermal conductivity of the gas-liquid two phases, and the ratio of the thermal conductivity of the gas-liquid two phases is related. When the temperature of the heat pipe was changed, the difference of heat storage ability between gas and liquid will lead to the phenomenon of heat reflux and becomes more pronounced with the increases of the temperature wave.

  2. In-situ ambient quantification of monoterpenes, sesquiterpenes, and related oxygenated compounds during BEARPEX 2007: implications for gas- and particle-phase chemistry

    Directory of Open Access Journals (Sweden)

    N. C. Bouvier-Brown

    2009-08-01

    Full Text Available We quantified ambient mixing ratios of 9 monoterpenes, 6 sesquiterpenes, methyl chavicol, the oxygenated terpene linalool, and nopinone using an in-situ gas chromatograph with a quadrupole mass spectrometer (GC-MS. These measurements were a part of the 2007 Biosphere Effects on AeRosols and Photochemistry EXperiment (BEARPEX at Blodgett Forest, a ponderosa pine forest in the Sierra Nevada Mountains of California. To our knowledge, these observations represent the first direct in-situ ambient quantification of the sesquiterpenes α-bergamotene, longifolene, α-farnesene, and β-farnesene. From average diurnal mixing ratio profiles, we show that α-farnesene emissions are dependent mainly on temperature whereas α-bergamotene and β-farnesene emissions are temperature- and light-dependent. The amount of sesquiterpene mass quantified above the canopy was small (averaging a total of 3.3 ppt during the day, but nevertheless these compounds contributed 7.6% to the overall ozone-olefin loss rate above the canopy. Assuming that the monoterpene-to-sesquiterpene emission rate in the canopy is similar to that observed in branch enclosure studies at the site during comparable weather conditions, and the average yield of aerosol mass from these sesquiterpenes is 10–50%, the amount of sesquiterpene mass reacted within the Blodgett Forest canopy alone accounts for 6–32% of the total organic aerosol mass measured during BEARPEX. The oxygenated monoterpene linalool was also quantified for the first time at Blodgett Forest. The linalool mass contribution was small (9.9 ppt and 0.74 ppt within and above the canopy, respectively, but it contributed 1.1% to the total ozone-olefin loss rate above the canopy. Reactive and semi-volatile compounds, especially sesquiterpenes, significantly impact the gas- and particle-phase chemistry of the atmosphere at Blodgett Forest and should be included in both biogenic volatile organic carbon emission and atmospheric chemistry

  3. Coated particle fuel for high temperature gas cooled reactors

    Energy Technology Data Exchange (ETDEWEB)

    Verfondern, Karl; Nabielek, Heinz [Research Center Julich (FZJ), Julich (Germany); Kendall, James M. [Global Virtual L1c, Prescott (United States)

    2007-10-15

    applications at 850-900 .deg. C and for process heat/hydrogen generation applications with 950 .deg. C outlet temperatures. There is a clear set of standards for modern high quality fuel in terms of low levels of heavy metal contamination, manufacture-induced particle defects during fuel body and fuel element making, irradiation/accident induced particle failures and limits on fission product release from intact particles. While gas-cooled reactor design is still open-ended with blocks for the prismatic and spherical fuel elements for the pebble-bed design, there is near worldwide agreement on high quality fuel: a 500 {mu}m diameter UO{sub 2} kernel of 10% enrichment is surrounded by a 100 {mu}m thick sacrificial buffer layer to be followed by a dense inner pyrocarbon layer, a high quality silicon carbide layer of 35 {mu}m thickness and theoretical density and another outer pyrocarbon layer. Good performance has been demonstrated both under operational and under accident conditions, i.e. to 10% FIMA and maximum 1600 .deg. C afterwards. And it is the wide-ranging demonstration experience that makes this particle superior. Recommendations are made for further work: 1. Generation of data for presently manufactured materials, e.g. SiC strength and strength distribution, PyC creep and shrinkage and many more material data sets. 2. Renewed start of irradiation and accident testing of modern coated particle fuel. 3. Analysis of existing and newly created data with a view to demonstrate satisfactory performance at burnups beyond 10% FIMA and complete fission product retention even in accidents that go beyond 1600 .deg. C for a short period of time. This work should proceed at both national and international level.

  4. Coated particle fuel for high temperature gas cooled reactors

    International Nuclear Information System (INIS)

    Verfondern, Karl; Nabielek, Heinz; Kendall, James M.

    2007-01-01

    and for process heat/hydrogen generation applications with 950 .deg. C outlet temperatures. There is a clear set of standards for modern high quality fuel in terms of low levels of heavy metal contamination, manufacture-induced particle defects during fuel body and fuel element making, irradiation/accident induced particle failures and limits on fission product release from intact particles. While gas-cooled reactor design is still open-ended with blocks for the prismatic and spherical fuel elements for the pebble-bed design, there is near worldwide agreement on high quality fuel: a 500 μm diameter UO 2 kernel of 10% enrichment is surrounded by a 100 μm thick sacrificial buffer layer to be followed by a dense inner pyrocarbon layer, a high quality silicon carbide layer of 35 μm thickness and theoretical density and another outer pyrocarbon layer. Good performance has been demonstrated both under operational and under accident conditions, i.e. to 10% FIMA and maximum 1600 .deg. C afterwards. And it is the wide-ranging demonstration experience that makes this particle superior. Recommendations are made for further work: 1. Generation of data for presently manufactured materials, e.g. SiC strength and strength distribution, PyC creep and shrinkage and many more material data sets. 2. Renewed start of irradiation and accident testing of modern coated particle fuel. 3. Analysis of existing and newly created data with a view to demonstrate satisfactory performance at burnups beyond 10% FIMA and complete fission product retention even in accidents that go beyond 1600 .deg. C for a short period of time. This work should proceed at both national and international level

  5. Experimental optimization of temperature distribution in the hot-gas duct through the installation of internals in the hot-gas plenum of a high-temperature reactor

    International Nuclear Information System (INIS)

    Henssen, J.; Mauersberger, R.

    1990-01-01

    The flow conditions in the hot-gas plenum and in the adjacent hot-gas ducts and hot-gas pipes for the high-temperature reactor project PNP-1000 (nuclear process heat project for 1000 MW thermal output) have been examined experimentally. The experiments were performed in a closed loop in which the flow model to be analyzed, representing a 60deg sector of the core bottom of the PNP-1000 with connecting hot-gas piping and diverting arrangements, was installed. The model scale was approx. 1:5.6. The temperature and flow velocity distribution in the hot-gas duct was registered by means of 14 dual hot-wire flowmeters. Through structural changes and/or the installation of internals into the hot-gas plenum of the core bottom offering little flow resistance coolant gas temperature differentials produced in the core could be reduced to such an extent that a degree of mixture amounting to over 80% was achieved at the entrance of the connected heat exchanger systems. Thereby the desired goal of an adequate degree of mixture of the hot gas involving an acceptable pressure loss was reached. (orig.)

  6. High pressure flow reactor for in situ X-ray absorption spectroscopy of catalysts in gas-liquid mixtures—A case study on gas and liquid phase activation of a Co-Mo/Al2O3 hydrodesulfurization catalyst

    NARCIS (Netherlands)

    van Haandel, L.; Hensen, E.J.M.; Weber, Th.

    2017-01-01

    An in situ characterization of heterogeneous catalysts under industrial operating conditions may involve high pressure and reactants in both the gas and the liquid phase. In this paper, we describe an in situ XAS flow reactor, which is suitable to operate under such conditions (pmax 20 bar, Tmax 350

  7. In situ rheology and gas volume in Hanford double-shell waste tanks

    International Nuclear Information System (INIS)

    Stewart, C.W.; Alzheimer, J.M.; Brewster, M.E.; Chen, G.; Reid, H.C.; Shepard, C.L.; Terrones, G.; Mendoza, R.E.

    1996-09-01

    This report is a detailed characterization of gas retention and release in 6 Hanford DS waste tanks. The results came from the ball rheometer and void fraction instrument in (flammable gas watch list) tanks SY-101, SY-103, AW-101, AN-103, AN-104, and AN-105 are presented. Instrument operation and derivation of data reduction methods are presented. Gas retention and release information is summarized for each tank and includes tank fill history and instrumentation, waste configuration, gas release, void fraction distribution, gas volumes, rheology, and photographs of the waste column from extruded core samples. Potential peak burn pressure is computed as a function of gas release fraction to portray the 'hazard signature' of each tank. It is shown that two tanks remain well below the maximum allowable pressure, even if the entire gas content were released and ignited, and that none of the others present a hazard with their present gas release behavior

  8. Proliferation resistance assessment of high temperature gas reactors

    Energy Technology Data Exchange (ETDEWEB)

    Chikamatsu N, M. A. [Instituto Tecnologico y de Estudios Superiores de Monterrey, Campus Santa Fe, Av. Carlos Lazo No. 100, Santa Fe, 01389 Mexico D. F. (Mexico); Puente E, F., E-mail: midori.chika@gmail.com [ININ, Carretera Mexico-Toluca s/n, 52750 Ocoyoacac, Estado de Mexico (Mexico)

    2014-10-15

    The Generation IV International Forum has established different objectives for the new generation of reactors to accomplish. These objectives are focused on sustain ability, safety, economics and proliferation resistance. This paper is focused on how the proliferation resistance of the High Temperature Gas Reactors (HTGR) is assessed and the advantages that these reactors present currently. In this paper, the focus will be on explaining why such reactors, HTGR, can achieve the goals established by the GIF and can present a viable option in terms of proliferation resistance, which is an issue of great importance in the field of nuclear energy generation. The reason why the HTGR are being targeted in this writing is that these reactors are versatile, and present different options from modular reactors to reactors with the same size as the ones that are being operated today. Besides their versatility, the HTGR has designed features that might improve on the overall sustain ability of the nuclear reactors. This is because the type of safety features and materials that are used open up options for industrial processes to be carried out; cogeneration for instance. There is a small section that mentions how HTGR s are being developed in the international sector in order to present the current world view in this type of technology and the further developments that are being sought. For the proliferation resistance section, the focus is on both the intrinsic and the extrinsic features of the nuclear systems. The paper presents a comparison between the features of Light Water Reactors (LWR) and the HTGR in order to be able to properly compare the most used technology today and one that is gaining international interest. (Author)

  9. Proliferation resistance assessment of high temperature gas reactors

    International Nuclear Information System (INIS)

    Chikamatsu N, M. A.; Puente E, F.

    2014-10-01

    The Generation IV International Forum has established different objectives for the new generation of reactors to accomplish. These objectives are focused on sustain ability, safety, economics and proliferation resistance. This paper is focused on how the proliferation resistance of the High Temperature Gas Reactors (HTGR) is assessed and the advantages that these reactors present currently. In this paper, the focus will be on explaining why such reactors, HTGR, can achieve the goals established by the GIF and can present a viable option in terms of proliferation resistance, which is an issue of great importance in the field of nuclear energy generation. The reason why the HTGR are being targeted in this writing is that these reactors are versatile, and present different options from modular reactors to reactors with the same size as the ones that are being operated today. Besides their versatility, the HTGR has designed features that might improve on the overall sustain ability of the nuclear reactors. This is because the type of safety features and materials that are used open up options for industrial processes to be carried out; cogeneration for instance. There is a small section that mentions how HTGR s are being developed in the international sector in order to present the current world view in this type of technology and the further developments that are being sought. For the proliferation resistance section, the focus is on both the intrinsic and the extrinsic features of the nuclear systems. The paper presents a comparison between the features of Light Water Reactors (LWR) and the HTGR in order to be able to properly compare the most used technology today and one that is gaining international interest. (Author)

  10. The Integration Of Process Heat Applications To High Temperature Gas Reactors

    International Nuclear Information System (INIS)

    McKellar, Michael G.

    2011-01-01

    A high temperature gas reactor, HTGR, can produce industrial process steam, high-temperature heat-transfer gases, and/or electricity. In conventional industrial processes, these products are generated by the combustion of fossil fuels such as coal and natural gas, resulting in significant emissions of greenhouse gases such as carbon dioxide. Heat or electricity produced in an HTGR could be used to supply process heat or electricity to conventional processes without generating any greenhouse gases. Process heat from a reactor needs to be transported by a gas to the industrial process. Two such gases were considered in this study: helium and steam. For this analysis, it was assumed that steam was delivered at 17 MPa and 540 C and helium was delivered at 7 MPa and at a variety of temperatures. The temperature of the gas returning from the industrial process and going to the HTGR must be within certain temperature ranges to maintain the correct reactor inlet temperature for a particular reactor outlet temperature. The returning gas may be below the reactor inlet temperature, ROT, but not above. The optimal return temperature produces the maximum process heat gas flow rate. For steam, the delivered pressure sets an optimal reactor outlet temperature based on the condensation temperature of the steam. ROTs greater than 769.7 C produce no additional advantage for the production of steam.

  11. Determination of an instability temperature for alloys in the cooling gas of a high temperature reactor

    International Nuclear Information System (INIS)

    Grimmer, H.; Grman, D.; Krompholz, K.; Zimmermann, U.; Ullrich, G.

    1985-05-01

    High temperature alloys designed to be used for components in the primary circuit of a helium cooled high temperature nuclear reactor show massive CO production above a certain temperature, called the instability temperature T/sub i/, which increases with increasing partial pressure of CO in the cooling gas. At p/sub CO/ = 15 microbar, T/sub i/ lies between 900 and 950 degrees C for the four alloys under investigation: T/sub i/ is lowest for the iron base alloy Incoloy 800 H and increases for the nickel base alloys in the order Inconel 617, HDA 230 and Nimonic 86. Measurements of T/sub i/ made at 3 different laboratories were compared and shown to agree for p/sub CO/ 25 microbar, compatible with CO production by a reaction of Cr2O3 with carbides. Some measurements of T/sub i/ on HDA 230 and Nimonic 86 were performed in the course of simulated reactor disturbances. They showed that the oxide layer looses its protective properties above T/sub i/. A highlight of the examinations was the detection of eta-carbides (M6C) with unusual properties. M6C is the only type of carbide occuring in HDA 230. An eta-carbide with a lattice constant of 1088.8 pm had developed at the surface of Nimonic 86 during pre-oxidation before the disturbance simulation. Its composition is estimated at Ni3SiMo2C. Eta-carbides containing Si and especially eta-carbides with lattice constants as low as 1088.8 pm have been described only rarely until now. (author)

  12. A low-temperature (4-300K) constant volume gas thermometer

    International Nuclear Information System (INIS)

    Combarieu, A. de

    1976-01-01

    A constant volume gas thermometer was built to calibrate the various secondary thermometers used at low temperature. This gas thermometer is placed in a cryostat where any stable temperature between 4 and 300K may be obtained. The principle is outlined, then the gas thermometer and its auxiliary equipment are briefly described; the corrections to be applied to the results are given and a table shows the values obtained [fr

  13. In situ synthesis of manganese oxides on polyester fiber for formaldehyde decomposition at room temperature

    Science.gov (United States)

    Wang, Jinlong; Yunus, Rizwangul; Li, Jinge; Li, Peilin; Zhang, Pengyi; Kim, Jeonghyun

    2015-12-01

    Removal of low-level formaldehyde (HCHO) is of great interest for indoor air quality improvement. Supported materials especially those with low air pressure drop are of necessity for air purification. Manganese oxides (MnOx) was in situ deposited on the surface of fibers of a non-woven fabric made of polyethylene terephthalate (PET). As-synthesized MnOx/PET were characterized by SEM, XRD, TEM, ATR-FTIR and XPS analysis. The growth of MnOx layer on PET is thought to start with partial hydrolysis of PET, followed by surface oxidation by KMnO4 and then surface-deposition of MnOx particles from the bulk phase. The MnOx particles assembled with nanosheets were uniformly coated on the PET fibers. MnOx/PET showed good activity for HCHO decomposition at room temperature which followed the Mars-van Krevelen mechanism. The removal of HCHO was kept over 94% after 10 h continuous reaction under the conditions of inlet HCHO concentration ∼0.6 mg/m3, space velocity ∼17,000 h-1 and relative humidity∼50%. This research provides a facile method to deposit active MnOx onto polymers with low air resistance, and composite MnOx/PET material is promising for indoor air purification.

  14. Modeling of Aerobrake Ballute Stagnation Point Temperature and Heat Transfer to Inflation Gas

    Science.gov (United States)

    Bahrami, Parviz A.

    2012-01-01

    A trailing Ballute drag device concept for spacecraft aerocapture is considered. A thermal model for calculation of the Ballute membrane temperature and the inflation gas temperature is developed. An algorithm capturing the most salient features of the concept is implemented. In conjunction with the thermal model, trajectory calculations for two candidate missions, Titan Explorer and Neptune Orbiter missions, are used to estimate the stagnation point temperature and the inflation gas temperature. Radiation from both sides of the membrane at the stagnation point and conduction to the inflating gas is included. The results showed that the radiation from the membrane and to a much lesser extent conduction to the inflating gas, are likely to be the controlling heat transfer mechanisms and that the increase in gas temperature due to aerodynamic heating is of secondary importance.

  15. In situ thermal conductivity of gas-hydrate-bearing sediments of the Mallik 5L-38 well

    Science.gov (United States)

    Henninges, J.; Huenges, E.; Burkhardt, H.

    2005-11-01

    Detailed knowledge about thermal properties of rocks containing gas hydrate is required in order to quantify processes involving gas hydrate formation and decomposition in nature. In the framework of the Mallik 2002 program, three wells penetrating a continental gas hydrate occurrence under permafrost were successfully equipped with permanent fiber-optic distributed temperature sensing cables. Temperature data were collected over a 21-month period after completing the wells. Thermal conductivity profiles were calculated from the geothermal data as well as from a petrophysical model derived from the available logging data and application of mixing law models. Results indicate that thermal conductivity variations are mainly lithologically controlled with a minor influence from hydrate saturation. Average thermal conductivity values of the hydrate-bearing sediments range between 2.35 and 2.77 W m-1 K-1. Maximum gas hydrate saturations can reach up to about 90% at an average porosity of 0.3.

  16. In situ synthesis of manganese oxides on polyester fiber for formaldehyde decomposition at room temperature

    International Nuclear Information System (INIS)

    Wang, Jinlong; Yunus, Rizwangul; Li, Jinge; Li, Peilin; Zhang, Pengyi; Kim, Jeonghyun

    2015-01-01

    Graphical abstract: - Highlights: • The MnO x particles assembled with nanosheets were uniformly coated on PET fibers. • The growth process of MnO x layer on PET is clearly clarified. • MnO x /PET showed good activity for HCHO decomposition at room temperature. • MnO x /PET material is promising for indoor air purification due to its light, flexible and low air-resistant properties. - Abstract: Removal of low-level formaldehyde (HCHO) is of great interest for indoor air quality improvement. Supported materials especially those with low air pressure drop are of necessity for air purification. Manganese oxides (MnO x ) was in situ deposited on the surface of fibers of a non-woven fabric made of polyethylene terephthalate (PET). As-synthesized MnO x /PET were characterized by SEM, XRD, TEM, ATR-FTIR and XPS analysis. The growth of MnO x layer on PET is thought to start with partial hydrolysis of PET, followed by surface oxidation by KMnO 4 and then surface-deposition of MnO x particles from the bulk phase. The MnO x particles assembled with nanosheets were uniformly coated on the PET fibers. MnO x /PET showed good activity for HCHO decomposition at room temperature which followed the Mars–van Krevelen mechanism. The removal of HCHO was kept over 94% after 10 h continuous reaction under the conditions of inlet HCHO concentration ∼0.6 mg/m 3 , space velocity ∼17,000 h −1 and relative humidity∼50%. This research provides a facile method to deposit active MnO x onto polymers with low air resistance, and composite MnO x /PET material is promising for indoor air purification.

  17. In situ synthesis of manganese oxides on polyester fiber for formaldehyde decomposition at room temperature

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Jinlong [State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084 (China); Collaborative Innovation Center for Regional Environmental Quality (China); Yunus, Rizwangul [State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084 (China); Xinjiang Zhongtai Chemical Company, Xinjiang 831511 (China); Li, Jinge; Li, Peilin [State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084 (China); Zhang, Pengyi, E-mail: zpy@tsinghua.edu.cn [State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084 (China); Collaborative Innovation Center for Regional Environmental Quality (China); Kim, Jeonghyun [State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084 (China); Collaborative Innovation Center for Regional Environmental Quality (China)

    2015-12-01

    Graphical abstract: - Highlights: • The MnO{sub x} particles assembled with nanosheets were uniformly coated on PET fibers. • The growth process of MnO{sub x} layer on PET is clearly clarified. • MnO{sub x}/PET showed good activity for HCHO decomposition at room temperature. • MnO{sub x}/PET material is promising for indoor air purification due to its light, flexible and low air-resistant properties. - Abstract: Removal of low-level formaldehyde (HCHO) is of great interest for indoor air quality improvement. Supported materials especially those with low air pressure drop are of necessity for air purification. Manganese oxides (MnO{sub x}) was in situ deposited on the surface of fibers of a non-woven fabric made of polyethylene terephthalate (PET). As-synthesized MnO{sub x}/PET were characterized by SEM, XRD, TEM, ATR-FTIR and XPS analysis. The growth of MnO{sub x} layer on PET is thought to start with partial hydrolysis of PET, followed by surface oxidation by KMnO{sub 4} and then surface-deposition of MnO{sub x} particles from the bulk phase. The MnO{sub x} particles assembled with nanosheets were uniformly coated on the PET fibers. MnO{sub x}/PET showed good activity for HCHO decomposition at room temperature which followed the Mars–van Krevelen mechanism. The removal of HCHO was kept over 94% after 10 h continuous reaction under the conditions of inlet HCHO concentration ∼0.6 mg/m{sup 3}, space velocity ∼17,000 h{sup −1} and relative humidity∼50%. This research provides a facile method to deposit active MnO{sub x} onto polymers with low air resistance, and composite MnO{sub x}/PET material is promising for indoor air purification.

  18. Loading rate and test temperature effects on fracture of in situ niobium silicide-niobium composites

    International Nuclear Information System (INIS)

    Rigney, J.D.; Lewandowski, J.J.

    1996-01-01

    Arc cast, extruded, and heat-treated in situ composites of niobium silicide (Nb 5 Si 3 ) intermetallic with niobium phases (primary--Nb p and secondary--Nb s ) exhibited high fracture resistance in comparison to monolithic Nb 5 Si 3 . In toughness tests conducted at 298 K and slow applied loading rates, the fracture process proceeded by the microcracking of the Nb 5 Si 3 and plastic deformation of the Nb p and Nb s phases, producing resistance-curve behavior and toughnesses of 28 MPa√m with damage zone lengths less than 500 microm. The effects of changes in the Nb p yield strength and fracture behavior on the measured toughnesses were investigated by varying the loading rates during fracture tests at both 77 and 298 K. Quantitative fractography was utilized to completely characterize each fracture surface created at 298 K in order to determine the type of fracture mode (i.e., dimpled, cleavage) exhibited by the Nb p . Specimens tested at either higher loading rates or lower test temperatures consistently exhibited a greater amount of cleavage fracture in the Nb p , while the Nb s always remained ductile. However, the fracture toughness values determined from experiments spanning six orders of magnitude in loading rate at 298 and 77 K exhibited little variation, even under conditions when the majority of Nb p phases failed by cleavage at 77 K. The changes in fracture mode with increasing loading rate and/or decreasing test temperature and their effects on fracture toughness are rationalized by comparison to existing theoretical models

  19. Phase transformation in delta Pu alloys at low temperature: in situ dilatometric study

    Energy Technology Data Exchange (ETDEWEB)

    Texier, G.; Oudot, B.; Platteau, C.; Ravat, B.; Delaunay, F. [CEA Valduc, 21 - Is-sur-Tille (France)

    2010-07-01

    The purpose of this work is to precisely study the martensitic transformation in a plutonium-gallium alloy. Thus, the thermodynamics and kinetics of the {delta} {yields} {alpha}' + {delta} transformation in a Pu-Ga alloy were studied under isochronal and isothermal conditions. The activation energy of the {delta} {yields} {alpha}' + {delta} phase transformation at a constant cooling rate (0.5 K. min{sup -1}) was determined by using Kissinger and Ozawa models. The average value of the activation energy was found to be at -56 kJ.mol{sup -1}. Dilatometry measurement was also used to trace 'in situ' the entire transformation for several temperatures. The kinetics of the {delta} {yields} {alpha}' + {delta} transformation were modelled under isothermal conditions in the theoretical frame of the Johnson-Mehl-Avrami-Kolmogorov (JMAK) theory. It is proposed that the transformation consists of three stages. The {alpha}' transformation begins with a nucleation of pre-existing embryos. Then, both nucleation and rapid growth of {alpha}' occurs simultaneously and finally, the plates width expend. Apparent activation energies for nucleation and growth transformation were determined from the temperature dependence of the constant K at respectively -34 kJ.mol{sup -1} and -60 kJ.mol{sup -1}. Dler et al. [1] investigated also the thermodynamics and the kinetics of the martensitic transformation in Pu alloys. These nucleation energies were found by modelling of heterogeneous martensitic nucleation via strain interaction with observed superdislocation-like nucleation sites in PuGa alloys. The values obtain by this model was very close to those we find. Investigations in steels alloys indicate that these energies are of the same order for nucleation near dislocation. Then, it could be indicating a strong relationship between these dislocations and martensitic nucleation sites. (authors)

  20. Phase transformation in {delta} Pu alloys at low temperature: In situ dilatometric study

    Energy Technology Data Exchange (ETDEWEB)

    Texier, G; Oudot, B; Platteau, C; Ravat, B; Delaunay, F, E-mail: gwenael.texier@cea.fr, E-mail: benoit.oudot@cea.fr [CEA, DAM, Valduc, Is sur Tille 21120 (France)

    2010-03-15

    The purpose of this work is to precisely study the martensitic transformation in a plutonium-gallium alloy. Thus, the thermodynamics and kinetics of the {delta}{yields}{alpha}'+{delta} phase transformation in a Pu-Ga alloy were studied under isochronal and isothermal conditions. The activation energy of the {delta}{yields}{alpha}'+{delta} phase transformation at a constant cooling rate (0.5 K.min{sup -1}) was determined by using Kissinger and Ozawa models. The average value of the activation energy was found to be at -56 kJ.mol{sup -1}. Dilatometry measurement was also used to trace 'in situ' the entire transformation for several temperatures. The kinetics of the {delta}{yields}{alpha}'+{delta} transformation were modelled under isothermal conditions in the theoretical frame of the Johnson-Mehl-Avrami-Kolmogorov (JMAK) theory. It is proposed that the transformation consists of three stages. The {alpha}' transformation begins with a nucleation of pre-existing embryos. Then, both nucleation and rapid growth of {alpha}' occurs simultaneously and finally, the plates width expend. Apparent activation energies for nucleation and growth transformation were determined from the temperature dependence of the constant K at respectively -34 kJ.mol{sup -1} and -60 kJ.mol{sup -1}. Adler et al. [1] investigated also the thermodynamics and the kinetics of the martensitic transformation in Pu alloys. These nucleation energies were found by modelling of heterogeneous martensitic nucleation via strain interaction with observed superdislocation-like nucleation sites in PuGa alloys. The values obtain by this model was very close to those we find. Investigations in steels alloys indicate that these energies are of the same order for nucleation near dislocation. Then, it could be indicating a strong relationship between these dislocations and martensitic nucleation sites.

  1. Gas Between the Stars: What Determines its Temperature?

    Indian Academy of Sciences (India)

    The interstellar gas in galaxies is heated by stellar radiationand cosmic rays and it also cools through radiation. We takea detailed look at these processes in order to understand thethermal state of equilibrium of the interstellar gas. This gasalso manifests itself in different 'phases'– molecular, neutralatomic and ionized, ...

  2. Thin film thermocouples for in situ membrane electrode assembly temperature measurements in a polybenzimidazole-based high temperature proton exchange membrane unit cell

    DEFF Research Database (Denmark)

    Ali, Syed Talat; Lebæk, Jesper; Nielsen, Lars Pleth

    2010-01-01

    m thick layer of TFTCs on 75 mu m thick Kapton foil. The Kapton foil was treated with in situ argon plasma etching to improve the adhesion between TFTCs and the Kapton substrate. The TFTCs were covered with a 7 mu m liquid Kapton layer using spin coating technique to protect them from environmental......This paper presents Type-T thin film thermocouples (TFTCs) fabricated on Kapton (polyimide) substrate for measuring the internal temperature of PBI(polybenzimidazole)-based high temperature proton exchange membrane fuel cell (HT-PEMFC). Magnetron sputtering technique was employed to deposit a 2 mu...... degradation. This Kapton foil with deposited TFTCs was used as sealing inside a PBI (polybenzimidazole)-based single cell test rig, which enabled measurements of in situ temperature variations of the working fuel cell MEA. The performance of the TFTCs was promising with minimal interference to the operation...

  3. In situ temperature relationships of biochemical and stomatal controls of photosynthesis in four lowland tropical tree species.

    Science.gov (United States)

    Slot, Martijn; Winter, Klaus

    2017-12-01

    Net photosynthetic carbon uptake of Panamanian lowland tropical forest species is typically optimal at 30-32 °C. The processes responsible for the decrease in photosynthesis at higher temperatures are not fully understood for tropical trees. We determined temperature responses of maximum rates of RuBP-carboxylation (V CMax ) and RuBP-regeneration (J Max ), stomatal conductance (G s ), and respiration in the light (R Light ) in situ for 4 lowland tropical tree species in Panama. G s had the lowest temperature optimum (T Opt ), similar to that of net photosynthesis, and photosynthesis became increasingly limited by stomatal conductance as temperature increased. J Max peaked at 34-37 °C and V CMax ~2 °C above that, except in the late-successional species Calophyllum longifolium, in which both peaked at ~33 °C. R Light significantly increased with increasing temperature, but simulations with a photosynthesis model indicated that this had only a small effect on net photosynthesis. We found no evidence for Rubisco-activase limitation of photosynthesis. T Opt of V CMax and J Max fell within the observed in situ leaf temperature range, but our study nonetheless suggests that net photosynthesis of tropical trees is more strongly influenced by the indirect effects of high temperature-for example, through elevated vapour pressure deficit and resulting decreases in stomatal conductance-than by direct temperature effects on photosynthetic biochemistry and respiration. © 2017 John Wiley & Sons Ltd.

  4. Silicon Carbide-Based Hydrogen Gas Sensors for High-Temperature Applications

    Directory of Open Access Journals (Sweden)

    Sangchoel Kim

    2013-10-01

    Full Text Available We investigated SiC-based hydrogen gas sensors with metal-insulator-semiconductor (MIS structure for high temperature process monitoring and leak detection applications in fields such as the automotive, chemical and petroleum industries. In this work, a thin tantalum oxide (Ta2O5 layer was exploited with the purpose of sensitivity improvement, because tantalum oxide has good stability at high temperature with high permeability for hydrogen gas. Silicon carbide (SiC was used as a substrate for high-temperature applications. We fabricated Pd/Ta2O5/SiC-based hydrogen gas sensors, and the dependence of their I-V characteristics and capacitance response properties on hydrogen concentrations were analyzed in the temperature range from room temperature to 500 °C. According to the results, our sensor shows promising performance for hydrogen gas detection at high temperatures.

  5. Scaling Studies for High Temperature Test Facility and Modular High Temperature Gas-Cooled Reactor

    Energy Technology Data Exchange (ETDEWEB)

    Richard R. Schult; Paul D. Bayless; Richard W. Johnson; James R. Wolf; Brian Woods

    2012-02-01

    The Oregon State University (OSU) High Temperature Test Facility (HTTF) is an integral experimental facility that will be constructed on the OSU campus in Corvallis, Oregon. The HTTF project was initiated, by the U.S. Nuclear Regulatory Commission (NRC), on September 5, 2008 as Task 4 of the 5-year High Temperature Gas Reactor Cooperative Agreement via NRC Contract 04-08-138. Until August, 2010, when a DOE contract was initiated to fund additional capabilities for the HTTF project, all of the funding support for the HTTF was provided by the NRC via their cooperative agreement. The U.S. Department of Energy (DOE) began their involvement with the HTTF project in late 2009 via the Next Generation Nuclear Plant (NGNP) project. Because the NRC's interests in HTTF experiments were only centered on the depressurized conduction cooldown (DCC) scenario, NGNP involvement focused on expanding the experimental envelope of the HTTF to include steady-state operations and also the pressurized conduction cooldown (PCC).

  6. Atom Probe Analysis of Ex Situ Gas-Charged Stable Hydrides.

    Science.gov (United States)

    Haley, Daniel; Bagot, Paul A J; Moody, Michael P

    2017-04-01

    In this work, we report on the atom probe tomography analysis of two metallic hydrides formed by pressurized charging using an ex situ hydrogen charging cell, in the pressure range of 200-500 kPa (2-5 bar). Specifically we report on the deuterium charging of Pd/Rh and V systems. Using this ex situ system, we demonstrate the successful loading and subsequent atom probe analysis of deuterium within a Pd/Rh alloy, and demonstrate that deuterium is likely present within the oxide-metal interface of a native oxide formed on vanadium. Through these experiments, we demonstrate the feasibility of ex situ hydrogen analysis for hydrides via atom probe tomography, and thus a practical route to three-dimensional imaging of hydrogen in hydrides at the atomic scale.

  7. High Temperature Gas Cooled Reactor Fuels and Materials

    International Nuclear Information System (INIS)

    2010-03-01

    At the third annual meeting of the technical working group on Nuclear Fuel Cycle Options and Spent Fuel Management (TWG-NFCO), held in Vienna, in 2004, it was suggested 'to develop manuals/handbooks and best practice documents for use in training and education in coated particle fuel technology' in the IAEA's Programme for the year 2006-2007. In the context of supporting interested Member States, the activity to develop a handbook for use in the 'education and training' of a new generation of scientists and engineers on coated particle fuel technology was undertaken. To make aware of the role of nuclear science education and training in all Member States to enhance their capacity to develop innovative technologies for sustainable nuclear energy is of paramount importance to the IAEA Significant efforts are underway in several Member States to develop high temperature gas cooled reactors (HTGR) based on either pebble bed or prismatic designs. All these reactors are primarily fuelled by TRISO (tri iso-structural) coated particles. The aim however is to build future nuclear fuel cycles in concert with the aim of the Generation IV International Forum and includes nuclear reactor applications for process heat, hydrogen production and electricity generation. Moreover, developmental work is ongoing and focuses on the burning of weapon-grade plutonium including civil plutonium and other transuranic elements using the 'deep-burn concept' or 'inert matrix fuels', especially in HTGR systems in the form of coated particle fuels. The document will serve as the primary resource materials for 'education and training' in the area of advanced fuels forming the building blocks for future development in the interested Member States. This document broadly covers several aspects of coated particle fuel technology, namely: manufacture of coated particles, compacts and elements; design-basis; quality assurance/quality control and characterization techniques; fuel irradiations; fuel

  8. Chemical composition and the nutritive value of pistachio epicarp (in situ degradation and in vitro gas production techniques

    Directory of Open Access Journals (Sweden)

    Somayeh Bakhshizadeh

    2014-04-01

    Full Text Available The nutritive value of pistachio epicarp (PE was evaluated by in situ and in vitro techniques. Chemical analysis indicated that PE was high in crude protein (11.30% and low in neutral detergent fiber (26.20%. Total phenols, total tannins, condensed tannins and hydrolysable tannins contents in PE were 8.29%, 4.48%, 0.49% and 3.79%, respectively. Ruminal dry matter and crude protein degradation after 48 hr incubation were 75.21% and 82.52%, respectively. The gas production volume at 48 hr for PE was 122.47 mL g-1DM. As a whole, adding polyethylene glycol (PEG to PE increased (p < 0.05 gas production volumes, organic matter digestibility and the metabolizable energy that illustrated inhibitory effect of phenolics on rumen microbial fermentation and the positive influence of PEG on digestion PE. The results showed that PE possessed potentials to being used as feed supplements.

  9. Chemical composition and the nutritive value of pistachio epicarp (in situ degradation and in vitro gas production techniques).

    Science.gov (United States)

    Bakhshizadeh, Somayeh; Taghizadeh, Akbar; Janmohammadi, Hossein; Alijani, Sadegh

    2014-01-01

    The nutritive value of pistachio epicarp (PE) was evaluated by in situ and in vitro techniques. Chemical analysis indicated that PE was high in crude protein (11.30%) and low in neutral detergent fiber (26.20%). Total phenols, total tannins, condensed tannins and hydrolysable tannins contents in PE were 8.29%, 4.48%, 0.49% and 3.79%, respectively. Ruminal dry matter and crude protein degradation after 48 hr incubation were 75.21% and 82.52%, respectively. The gas production volume at 48 hr for PE was 122.47 mL g(-1)DM. As a whole, adding polyethylene glycol (PEG) to PE increased (p gas production volumes, organic matter digestibility and the metabolizable energy that illustrated inhibitory effect of phenolics on rumen microbial fermentation and the positive influence of PEG on digestion PE. The results showed that PE possessed potentials to being used as feed supplements.

  10. Influence of the gas mixture radio on the correlations between the excimer XeCl emission and the sealed gas temperature in dielectric barrier discharge lamps

    CERN Document Server

    Xu Jin Zhou; Ren Zhao Xing

    2002-01-01

    For dielectric barrier discharge lamps filled with various gas mixture ratios, the correlations between the excimer XeCl emission and the sealed gas temperature have been founded, and a qualitative explication is presented. For gas mixture with chlorine larger than 3%, the emission intensity increases with the sealed gas temperature, while with chlorine about 2%, the emission intensity decreases with the increasing in the gas temperature, and could be improved by cooling water. However, if chlorine is less than 1.5%, the discharge appears to be a mixture mode with filaments distributed in a diffused glow-like discharge, and the UV emission is independent on the gas temperature

  11. Some problems on materials tests in high temperature hydrogen base gas mixture

    International Nuclear Information System (INIS)

    Shikama, Tatsuo; Tanabe, Tatsuhiko; Fujitsuka, Masakazu; Yoshida, Heitaro; Watanabe, Ryoji

    1980-01-01

    Some problems have been examined on materials tests (creep rupture tests and corrosion tests) in high temperature mixture gas of hydrogen (80%H 2 + 15%CO + 5%CO 2 ) simulating the reducing gas for direct steel making. H 2 , CO, CO 2 and CH 4 in the reducing gas interact with each other at elevated temperature and produce water vapor (H 2 O) and carbon (soot). Carbon deposited on the walls of retorts and the water condensed at pipings of the lower temperature gas outlet causes blocking of gas flow. The gas reactions have been found to be catalyzed by the retort walls, and appropriate selection of the materials for retorts has been found to mitigate the problems caused by water condensation and carbon deposition. Quartz has been recognized to be one of the most promising materials for minimizing the gas reactions. And ceramic coating, namely, BN (born nitride) on the heat resistant superalloy, MO-RE II, has reduced the amounts of water vapor and deposited carbon (sooting) produced by gas reactions and has kept dew points of outlet gas below room temperature. The well known emf (thermo-electromotive force) deterioration of Alumel-Chromel thermocouples in the reducing gases at elevated temperatures has been also found to be prevented by the ceramic (BN) coating. (author)

  12. A Long Gravity-Piston Corer Developed for Seafloor Gas Hydrate Coring Utilizing an In Situ Pressure-Retained Method

    Directory of Open Access Journals (Sweden)

    Lin-Yi Gu

    2013-07-01

    Full Text Available A corer, which can obtain long in situ pressure-retained sediments of up to 30 m core containing gas hydrates, has been applied in the South China Sea (SCS dozens of times. The corer presented in this paper is a convenient, efficient and economical long in situ pressure-retained coring and research tool for submarine sediments, that can applied to completely cope with all sediments close to the seafloor ranging from shallow waters to the deep sea depths of 6000 m. This article mainly presents the overall structure, working principles, key pressure-retained components, coring mechanism, sea trials and outlook of the corer. The analyses found that the coring ability was affected by formation characteristics, the outer diameter of the core barrels and inner diameter of the core liners, the shapes of the cutter and the dead weight of the corer. This study can provide the practical basis for the structural optimization of this type of corer and designs for corers with greater penetrability. Sea trials showed that the developed corer presented in this paper can support the in situ pressure of the seafloor sediment core, which is an improvement over the conventional piston corer.

  13. In situ oil burning in the marshland environment : soil temperatures resulting from crude oil and diesel fuel burns

    International Nuclear Information System (INIS)

    Bryner, N.P.; Walton, W.D.; Twilley, W.H.; Roadarmel, G.; Mendelssohn, I.A.; Lin, Q.; Mullin, J.V.

    2001-01-01

    The unique challenge associated with oil spill cleanups in sensitive marsh environments was discussed. Mechanical recovery of crude or refined hydrocarbons in wetlands may cause more damage to the marsh than the oil itself. This study evaluated whether in situ burning of oiled marshlands would provide a less damaging alternative than mechanical recovery. This was done through a series of 6 crude oil and 5 diesel fuel burns conducted in a test tank to examine the impact of intentional burning of oil spilled in a wetlands environment. There are several factors which may influence how well such an environment would recover from an in situ oil burn, such as plant species, fuel type and load, water level, soil type, and burn duration. This paper focused on soil, air and water temperatures, as well as total heat fluxes that resulted when 3 plant species were exposed to full-scale in situ burns that were created by burning diesel fuel and crude oil. The soil temperatures were monitored during the test burn at three different soil/water elevations for 700 second burn exposures. A total of 184 plant sods were harvested from marshlands in southern Louisiana and were subjected to the burning fuel. They were instrumental in characterizing the thermal and chemical stress that occur during an in-situ burn. The plants were inserted into the test tanks at various water and soil depths. The results indicated that diesel fuel and crude oil burns produced similar soil temperature profiles at each of three plant sod elevations. Although in-situ burning did not appear to remediate oil that had penetrated into the soil, it did effectively remove floating oil from the water surface, thereby preventing it from potentially contaminating adjacent habitats and penetrating the soil when the water recedes. The regrowth and recovery of the plants will be described in a separate report. 25 refs., 7 tabs., 15 figs

  14. Simulation of temperature-pressure profiles and wax deposition in gas-lift wells

    Directory of Open Access Journals (Sweden)

    Sevic Snezana

    2017-01-01

    Full Text Available Gas-lift is an artificial lift method in which gas is injected down the tubing- -casing annulus and enters the production tubing through the gas-lift valves to reduce the hydrostatic pressure of the formation fluid column. The gas changes pressure, temperature and fluid composition profiles throughout the production tubing string. Temperature and pressure drop along with the fluid composition changes throughout the tubing string can lead to wax, asphaltenes and inorganic salts deposition, increased emulsion stability and hydrate formation. This paper presents a new model that can sucesfully simulate temperature and pressure profiles and fluid composition changes in oil well that operates by means of gas-lift. This new model includes a pipe-in-pipe segment (production tubing inside production casing, countercurrent flow of gas-lift gas and producing fluid, heat exchange between gas-lift gas and the surrounding ambient – ground; and gas-lift gas with the fluid in the tubing. The model enables a better understanding of the multiphase fluid flow up the production tubing. Model was used to get insight into severity and locations of wax deposition. The obtained information on wax deposition can be used to plan the frequency and depth of wax removing operations. Model was developed using Aspen HYSYS software.

  15. Development of data logger for atmospheric pressure, temperature and relative humidity for gas-filled detector

    International Nuclear Information System (INIS)

    Sahu, S.; Sahu, P.K.; Bhuyan, M.R.; Biswas, S.; Mohanty, B.

    2014-01-01

    At IoP-NISER an initiative has been taken to build and test micro-pattern gas detector such as Gas Electron Multiplier (GEM) for several upcoming High-Energy Physics (HEP) experiment projects. Temperature (t), atmospheric pressure (p) and relative humidity (RH) monitor and recording is very important for gas filled detector development. A data logger to monitor and record the ambient parameters such as temperature, relative humidity and pressure has been developed. With this data logger continuous recording of t, p, RH and time stamp can be done with a programmable sampling interval. This data is necessary to correct the gain of a gas filled detector

  16. In situ observation of low temperature growth of Ge on Si(1 1 1) by reflection high energy electron diffraction

    International Nuclear Information System (INIS)

    Grimm, Andreas; Fissel, Andreas; Bugiel, Eberhard; Wietler, Tobias F.

    2016-01-01

    Highlights: • Investigation of the initial stages of epitaxial growth of Ge on Si(1 1 1) in situ by RHEED. • Impact of growth temperature on strain evolution for temperatures between 200 °C and 400 °C. • Epitaxy with a high degree of structural perfection already at growth temperature of 200 °C. • Ordered interfacial dislocation networks already at 200 °C. • Tensile strain contribution of Si(1 1 1) 7 × 7-surface reconstruction to strain relaxation process for epitaxial growth of Ge. - Abstract: In this paper we investigate the initial stages of epitaxial growth of Ge on Si(1 1 1) and the impact of growth temperature on strain evolution in situ by reflection high energy electron diffraction (RHEED) for temperatures between 200 °C and 400 °C. The change in surface morphology from a flat wetting layer to subsequent islanding that is characteristic for Stranski–Krastanov growth is monitored by spot intensity analysis. The corresponding critical layer thickness is determined to 3.1 < d c < 3.4 ML. In situ monitoring of the strain relaxation process reveals a contribution of the Si(1 1 1) 7 × 7-surface reconstruction to the strain relaxation process. High resolution transmission electron microscopy confirms that the Ge islands exhibit a high degree of structural perfection and an ordered interfacial misfit dislocation network already at a growth temperature of 200 °C is established. The temperature dependency of island shape, density and height is characterized by atomic force microscopy and compared to the RHEED investigations.

  17. A pressure core ultrasonic test system for on-board analysis of gas hydrate-bearing sediments under in situ pressures.

    Science.gov (United States)

    Yang, Lei; Zhou, Weihua; Xue, Kaihua; Wei, Rupeng; Ling, Zheng

    2018-05-01

    The enormous potential as an alternative energy resource has made natural gas hydrates a material of intense research interest. Their exploration and sample characterization require a quick and effective analysis of the hydrate-bearing cores recovered under in situ pressures. Here a novel Pressure Core Ultrasonic Test System (PCUTS) for on-board analysis of sediment cores containing gas hydrates at in situ pressures is presented. The PCUTS is designed to be compatible with an on-board pressure core transfer device and a long gravity-piston pressure-retained corer. It provides several advantages over laboratory core analysis including quick and non-destructive detection, in situ and successive acoustic property acquisition, and remission of sample storage and transportation. The design of the unique assembly units to ensure the in situ detection is demonstrated, involving the U-type protecting jackets, transducer precession device, and pressure stabilization system. The in situ P-wave velocity measurements make the detection of gas hydrate existence in the sediments possible on-board. Performance tests have verified the feasibility and sensitivity of the ultrasonic test unit, showing the dependence of P-wave velocity on gas hydrate saturation. The PCUTS has been successfully applied for analysis of natural samples containing gas hydrates recovered from the South China Sea. It is indicated that on-board P-wave measurements could provide a quick and effective understanding of the hydrate occurrence in natural samples, which can assist further resource exploration, assessment, and subsequent detailed core analysis.

  18. A pressure core ultrasonic test system for on-board analysis of gas hydrate-bearing sediments under in situ pressures

    Science.gov (United States)

    Yang, Lei; Zhou, Weihua; Xue, Kaihua; Wei, Rupeng; Ling, Zheng

    2018-05-01

    The enormous potential as an alternative energy resource has made natural gas hydrates a material of intense research interest. Their exploration and sample characterization require a quick and effective analysis of the hydrate-bearing cores recovered under in situ pressures. Here a novel Pressure Core Ultrasonic Test System (PCUTS) for on-board analysis of sediment cores containing gas hydrates at in situ pressures is presented. The PCUTS is designed to be compatible with an on-board pressure core transfer device and a long gravity-piston pressure-retained corer. It provides several advantages over laboratory core analysis including quick and non-destructive detection, in situ and successive acoustic property acquisition, and remission of sample storage and transportation. The design of the unique assembly units to ensure the in situ detection is demonstrated, involving the U-type protecting jackets, transducer precession device, and pressure stabilization system. The in situ P-wave velocity measurements make the detection of gas hydrate existence in the sediments possible on-board. Performance tests have verified the feasibility and sensitivity of the ultrasonic test unit, showing the dependence of P-wave velocity on gas hydrate saturation. The PCUTS has been successfully applied for analysis of natural samples containing gas hydrates recovered from the South China Sea. It is indicated that on-board P-wave measurements could provide a quick and effective understanding of the hydrate occurrence in natural samples, which can assist further resource exploration, assessment, and subsequent detailed core analysis.

  19. Transient fission gas release from UO2 fuel for high temperature and high burnup

    International Nuclear Information System (INIS)

    Szuta, M.

    2001-01-01

    In the present paper it is assumed that the fission gas release kinetics from an irradiated UO 2 fuel for high temperature is determined by the kinetics of grain growth. A well founded assumption that Vitanza curve describes the change of uranium dioxide re-crystallization temperature and the experimental results referring to the limiting grain size presented in the literature are used to modify the grain growth model. Algorithms of fission gas release due to re-crystallization of uranium dioxide grains are worked out. The defect trap model of fission gas behaviour described in the earlier papers is supplemented with the algorithms. Calculations of fission gas release in function of time, temperature, burn-up and initial grain sizes are obtained. Computation of transient fission gas release in the paper is limited to the case where steady state of irradiation to accumulate a desired burn-up is performed below the temperature of re-crystallization then the subsequent step temperature increase follows. There are considered two kinds of step temperature increase for different burn-up: the final temperature of the step increase is below and above the re-crystallization temperature. Calculations show that bursts of fission gas are predicted in both kinds. The release rate of gas liberated for the final temperature above the re-crystallization temperature is much higher than for final temperature below the re-crystallization temperature. The time required for the burst to subside is longer due to grain growth than due to diffusion of bubbles and knock-out release. The theoretical results explain qualitatively the experimental data but some of them need to be verified since this sort of experimental data are not found in the available literature. (author)

  20. High temperature in-situ observations of multi-segmented metal nanowires encapsulated within carbon nanotubes by in-situ filling technique.

    Science.gov (United States)

    Hayashi, Yasuhiko; Tokunaga, Tomoharu; Iijima, Toru; Iwata, Takuya; Kalita, Golap; Tanemura, Masaki; Sasaki, Katsuhiro; Kuroda, Kotaro

    2012-08-08

    Multi-segmented one-dimensional metal nanowires were encapsulated within carbon nanotubes (CNTs) through in-situ filling technique during plasma-enhanced chemical vapor deposition process. Transmission electron microscopy (TEM) and environmental TEM were employed to characterize the as-prepared sample at room temperature and high temperature. The selected area electron diffractions revealed that the Pd4Si nanowire and face-centered-cubic Co nanowire on top of the Pd nanowire were encapsulated within the bottom and tip parts of the multiwall CNT, respectively. Although the strain-induced deformation of graphite walls was observed, the solid-state phases of Pd4Si and Co-Pd remain even at above their expected melting temperatures and up to 1,550 ± 50°C. Finally, the encapsulated metals were melted and flowed out from the tip of the CNT after 2 h at the same temperature due to the increase of internal pressure of the CNT.

  1. High Temperature Gas-cooled Reactor Projected Markets and Scoping Economics

    Energy Technology Data Exchange (ETDEWEB)

    Larry Demick

    2010-08-01

    The NGNP Project has the objective of developing the high temperature gas-cooled reactor (HTGR) technology to supply high temperature process heat to industrial processes as a substitute for burning of fossil fuels, such as natural gas. Applications of the HTGR technology that have been evaluated by the NGNP Project for supply of process heat include supply of electricity, steam and high-temperature gas to a wide range of industrial processes, and production of hydrogen and oxygen for use in petrochemical, refining, coal to liquid fuels, chemical, and fertilizer plants.

  2. Investigation of ambient temperature on the performance of GE-F5 gas turbine

    International Nuclear Information System (INIS)

    Ghazikhani, M.; Taffazoli, D.; Manshori, N.

    2002-01-01

    The role of ambient temperature in determining the performance of GE-F5 gas turbine is analysed by investigating the Shirvan gas turbine power plant 10 MW , 15 MW and 20 MW power output. These parameters have been brought as a function of ambient temperature. The results show when ambient temperature increases 1 deg C, The compressor pressure decreases about 20 k Pa, compressor outlet temperature increases about 1.13 deg C and exhaust temperature increases about 2.5 deg C. It is revealed that variations are due to decreasing the efficiency of compressor and less due to mass flow rate of air reduction as ambient temperature increases at constant power output. The results shows cycle efficiency reduces 3% with increasing 50 of ambient temperature, also the m increases as ambient temperature increase for constant turbine work. These are also because of reducing the compressor efficiency as ambient temperature increases

  3. Multi-spectral pyrometer for gas turbine blade temperature measurement

    Science.gov (United States)

    Gao, Shan; Wang, Lixin; Feng, Chi

    2014-09-01

    To achieve the highest possible turbine inlet temperature requires to accurately measuring the turbine blade temperature. If the temperature of blade frequent beyond the design limits, it will seriously reduce the service life. The problem for the accuracy of the temperature measurement includes the value of the target surface emissivity is unknown and the emissivity model is variability and the thermal radiation of the high temperature environment. In this paper, the multi-spectral pyrometer is designed provided mainly for range 500-1000°, and present a model corrected in terms of the error due to the reflected radiation only base on the turbine geometry and the physical properties of the material. Under different working conditions, the method can reduce the measurement error from the reflect radiation of vanes, make measurement closer to the actual temperature of the blade and calculating the corresponding model through genetic algorithm. The experiment shows that this method has higher accuracy measurements.

  4. Monitoring of high temperature zone by resistivity tomography during in-situ heater test in sedimentary soft rocks

    International Nuclear Information System (INIS)

    Kubota, Kenji; Suzuki, Koichi; Ikenoya, Takafumi; Takakura, Nozomu; Tani, Kazuo

    2008-01-01

    In-situ heater test has been conducted to evaluate the influence of high temperature in an underground facility at a depth of 50 m. Resistivity monitoring is thought to be effective to map the extent of the high temperature zone. So we have conducted resistivity tomography during the heater test. As a result, low resistivity zone was appeared near the heated area as starting the heating, and the zone was expanded. Resistivity of rock is proportional to resistivity of pore water. It is known that pore water resistivity decreases as the temperature rise. This suggests that high temperature zone is detected and spatial distribution of temperature can be mapped by resistivity tomography. (author)

  5. High-Temperature, High-Bandwidth Fiber Optic Pressure and Temperature Sensors for Gas Turbine Applications

    National Research Council Canada - National Science Library

    Fielder, Robert S; Palmer, Matthew E

    2003-01-01

    The accurate measurement of gas flow conditions in the compressor, combustors, and turbines of gas turbine engines is important to assess performance, predict failure, and facilitate data-driven maintenance...

  6. Impact of process temperature on GaSb metal-oxide-semiconductor interface properties fabricated by ex-situ process

    Energy Technology Data Exchange (ETDEWEB)

    Yokoyama, Masafumi, E-mail: yokoyama@mosfet.t.u-tokyo.ac.jp; Takenaka, Mitsuru; Takagi, Shinichi [Department of Electrical Engineering and Information Systems, The University of Tokyo, Yayoi 2-11-16, Bunkyo, Tokyo 113-0032 (Japan); JST-CREST, Yayoi 2-11-16, Bunkyo, Tokyo 113-0032 (Japan); Asakura, Yuji [Department of Electrical Engineering and Information Systems, The University of Tokyo, Yayoi 2-11-16, Bunkyo, Tokyo 113-0032 (Japan); Yokoyama, Haruki [NTT Photonics Laboratories, NTT Corporation, Atsugi 243-0198 (Japan)

    2014-06-30

    We have studied the impact of process temperature on interface properties of GaSb metal-oxide-semiconductor (MOS) structures fabricated by an ex-situ atomic-layer-deposition (ALD) process. We have found that the ALD temperature strongly affects the Al{sub 2}O{sub 3}/GaSb MOS interface properties. The Al{sub 2}O{sub 3}/GaSb MOS interfaces fabricated at the low ALD temperature of 150 °C have the minimum interface-trap density (D{sub it}) of ∼4.5 × 10{sup 13 }cm{sup −2} eV{sup −1}. We have also found that the post-metalization annealing at temperature higher than 200 °C degrades the Al{sub 2}O{sub 3}/GaSb MOS interface properties. The low-temperature process is preferable in fabricating GaSb MOS interfaces in the ex-situ ALD process to avoid the high-temperature-induced degradations.

  7. In situ observation of high temperature tensile deformation and low cycle fatigue response in a nickel-base superalloy

    Energy Technology Data Exchange (ETDEWEB)

    Lu, Xudong, E-mail: lxdong0700@hotmail.com; Du, Jinhui; Deng, Qun

    2013-12-20

    High temperature tension and low cycle fatigue experiments of IN718 alloy have been performed in the electro-hydraulic servo system with scanning electron microscope at 455 °C. Fatigue crack initiation and propagation process are investigated in situ. Results show that the carbide and twin grain are the crack source of the low cycle fatigue of IN718 alloy, and the low cycle fatigue life of the alloy increases with the decrease in grain size.

  8. Basin-Wide Temperature Constraints On Gas Hydrate Stability In The Gulf Of Mexico

    Science.gov (United States)

    MacDonald, I. R.; Reagan, M. T.; Guinasso, N. L.; Garcia-Pineda, O. G.

    2012-12-01

    Gas hydrate deposits commonly occur at the seafloor-water interface on marine margins. They are especially prevalent in the Gulf of Mexico where they are associated with natural oil seeps. The stability of these deposits is potentially challenged by fluctuations in bottom water temperature, on an annual time-scale, and under the long-term influence of climate change. We mapped the locations of natural oil seeps where shallow gas hydrate deposits are known to occur across the entire Gulf of Mexico basin based on a comprehensive review of synthetic aperture radar (SAR) data (~200 images). We prepared a bottom water temperature map based on the archive of CTD casts from the Gulf (~6000 records). Comparing the distribution of gas hydrate deposits with predicted bottom water temperature, we find that a broad area of the upper slope lies above the theoretical stability horizon for structure 1 gas hydrate, while all sites where gas hydrate deposits occur are within the stability horizon for structure 2 gas hydrate. This is consistent with analytical results that structure 2 gas hydrates predominate on the upper slope (Klapp et al., 2010), where bottom water temperatures fluctuate over a 7 to 10 C range (approx. 600 m depth), while pure structure 1 hydrates are found at greater depths (approx. 3000 m). Where higher hydrocarbon gases are available, formation of structure 2 gas hydrate should significantly increase the resistance of shallow gas hydrate deposits to destabilizing effects variable or increasing bottom water temperature. Klapp, S.A., Bohrmann, G., Kuhs, W.F., Murshed, M.M., Pape, T., Klein, H., Techmer, K.S., Heeschen, K.U., and Abegg, F., 2010, Microstructures of structure I and II gas hydrates from the Gulf of Mexico: Marine and Petroleum Geology, v. 27, p. 116-125.Bottom temperature and pressure for Gulf of Mexico gas hydrate outcrops and stability horizons for sI and sII hydrate.

  9. Characterization of oxidation resistance of stainless steels at high temperature by metallographic examinations and in-situ electrical resistance measurements; Charakterisierung der Oxidationsbestaendigkeit in nichtrostenden Staehlen bei hoher Temperatur durch Metallographische Untersuchungen und In-Situ-Messungen des elektrischen Widerstands

    Energy Technology Data Exchange (ETDEWEB)

    Bruncko, Mihael; Rudolf, Rebeka; Anzel, Ivan [Maribor Univ. (Slovenia). Faculty of Mechanical Engineering; Mehrabi, Kambiz [Pankl Drivetrain Systems GmbH und Co. KG, Kapfenberg (Austria); Kneissl, Albert C. [Leoben Univ. (Austria). Dept. of Physical Metallurgy and Materials Testing

    2013-07-01

    Practically all metals and alloys survive high-temperature exposure by growing oxide scales and/or by precipitation of the oxide particles in the matrix. Formed products can grow in shape of external oxide layers on surfaces, or as discrete oxide particles precipitated in a metal matrix. The first case represents external oxidation, and the other case is called internal oxidation. These processes are very important, because they determine the properties and applicability of metallic materials. Generally, they are undesired, because they cause deterioration of the mechanical properties and decomposition of metallic material. On the other side, the controlled process of external oxidation could be used for formation of protective coatings and the internal oxidation for dispersion strengthening of materials. In this paper we present monitoring of high-temperature oxidation of X12Cr13 stainless steel by in-situ electrical resistance measurements at different annealing temperatures in the air atmosphere. We determined the kinetics of oxide scale formation and its morphology with additional metallographic examination made by optical and scanning electron microscopy. The results of this research work show that in-situ monitoring and characterization of high-temperature oxidation present a strong tool that will contribute to a better fundamental understanding of the phenomena that occur during high-temperature oxidation of metallic materials. (orig.)

  10. The challenge of multi-parameter hydrochemical, gas-physical, and isotopic analyses of in-situ clay pore water and samples from in-situ clay experiments

    International Nuclear Information System (INIS)

    Eichinger, L.; Lorenz, G.D.; Eichinger, F.; Wechner, S.; Voropaev, A.

    2012-01-01

    Document available in extended abstract form only. Within the research framework of natural clay rocks used as barriers for radioactive waste confinement comprehensive analyses are mandatory to determine the chemical and isotopic composition of natural pore water and therein dissolved gases as well as samples from distinct in-situ and lab experiments. Based on the natural conditions pore waters from low permeable argillaceous rocks can be sampled only in small amounts over long time periods. Often those samples are primarily influenced by processes of the exploration and exploitation such as the contamination by drilling fluid and disinfection fluid or cement-water interactions. Sophisticated equipment for circulation experiments allows the sampling of gas and water in the original state in steel and peek cells. The challenge though is to optimise the lab equipment and measurement techniques in a way that the physical-chemical conditions of the water can be analysed in the original state. The development of special micro measuring cells enables the analyses of physical parameters like redox potential under very slow through-flow conditions. Additional analyses can follow subsequently without wasting any drop of the precious pore water. The gas composition is measured in equilibrated gas phases above water phases after emptying a defined volume by inert gas or through manual pressure. The analytical challenge is to obtain an extensive set of parameters which is considered representative for the in-situ conditions using only a few millilitres of water. The parameter analysis includes the determination of the composition of the water, the isotopic compositions of the water and the dissolved constituents as well as their gas concentrations and isotopic signatures. So far the smallest sample volume needed for an analysis of a full set of parameters including the gas composition was 9 ml of water. Obviously, the analysis requires a highly sophisticated infrastructure and

  11. Acoustic travel time gauges for in-situ determination of pressure and temperature in multi-anvil apparatus

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Xuebing; Chen, Ting; Qi, Xintong [Department of Geosciences, Stony Brook University, Stony Brook, New York 11794 (United States); Zou, Yongtao; Liebermann, Robert C.; Li, Baosheng [Mineral Physics Institute, Stony Brook University, Stony Brook, New York 11794 (United States); Kung, Jennifer [Department of Earth Sciences, National Cheng Kung University, Tainan 70101, Taiwan (China); Yu, Tony; Wang, Yanbin [GeoSoilEnviroCARS, Center for Advanced Radiation Sources, The University of Chicago, 5640 S. Ellis Avenue, Chicago, Illinois 60637 (United States)

    2015-08-14

    In this study, we developed a new method for in-situ pressure determination in multi-anvil, high-pressure apparatus using an acoustic travel time approach within the framework of acoustoelasticity. The ultrasonic travel times of polycrystalline Al{sub 2}O{sub 3} were calibrated against NaCl pressure scale up to 15 GPa and 900 °C in a Kawai-type double-stage multi-anvil apparatus in conjunction with synchrotron X-radiation, thereby providing a convenient and reliable gauge for pressure determination at ambient and high temperatures. The pressures derived from this new travel time method are in excellent agreement with those from the fixed-point methods. Application of this new pressure gauge in an offline experiment revealed a remarkable agreement of the densities of coesite with those from the previous single crystal compression studies under hydrostatic conditions, thus providing strong validation for the current travel time pressure scale. The travel time approach not only can be used for continuous in-situ pressure determination at room temperature, high temperatures, during compression and decompression, but also bears a unique capability that none of the previous scales can deliver, i.e., simultaneous pressure and temperature determination with a high accuracy (±0.16 GPa in pressure and ±17 °C in temperature). Therefore, the new in-situ Al{sub 2}O{sub 3} pressure gauge is expected to enable new and expanded opportunities for offline laboratory studies of solid and liquid materials under high pressure and high temperature in multi-anvil apparatus.

  12. Acoustic travel time gauges for in-situ determination of pressure and temperature in multi-anvil apparatus

    International Nuclear Information System (INIS)

    Wang, Xuebing; Chen, Ting; Qi, Xintong; Zou, Yongtao; Liebermann, Robert C.; Li, Baosheng; Kung, Jennifer; Yu, Tony; Wang, Yanbin

    2015-01-01

    In this study, we developed a new method for in-situ pressure determination in multi-anvil, high-pressure apparatus using an acoustic travel time approach within the framework of acoustoelasticity. The ultrasonic travel times of polycrystalline Al 2 O 3 were calibrated against NaCl pressure scale up to 15 GPa and 900 °C in a Kawai-type double-stage multi-anvil apparatus in conjunction with synchrotron X-radiation, thereby providing a convenient and reliable gauge for pressure determination at ambient and high temperatures. The pressures derived from this new travel time method are in excellent agreement with those from the fixed-point methods. Application of this new pressure gauge in an offline experiment revealed a remarkable agreement of the densities of coesite with those from the previous single crystal compression studies under hydrostatic conditions, thus providing strong validation for the current travel time pressure scale. The travel time approach not only can be used for continuous in-situ pressure determination at room temperature, high temperatures, during compression and decompression, but also bears a unique capability that none of the previous scales can deliver, i.e., simultaneous pressure and temperature determination with a high accuracy (±0.16 GPa in pressure and ±17 °C in temperature). Therefore, the new in-situ Al 2 O 3 pressure gauge is expected to enable new and expanded opportunities for offline laboratory studies of solid and liquid materials under high pressure and high temperature in multi-anvil apparatus

  13. Current correlation functions of ideal Fermi gas at finite temperature

    Indian Academy of Sciences (India)

    in the study of time dependent density functional theory [5] due to the work of Vignale and. Kohn [6,7]. They obtained ... part has relevance to the study of viscous effects [10] in the electron gas and to the dia- magnetic ... is found that the diamagnetic susceptibility, related to the transverse part, smoothly cross over from ...

  14. Exhaust Gas Temperature Measurements in Diagnostics of Turbocharged Marine Internal Combustion Engines Part I Standard Measurements

    Directory of Open Access Journals (Sweden)

    Korczewski Zbigniew

    2015-01-01

    Full Text Available The article discusses the problem of diagnostic informativeness of exhaust gas temperature measurements in turbocharged marine internal combustion engines. Theoretical principles of the process of exhaust gas flow in turbocharger inlet channels are analysed in its dynamic and energetic aspects. Diagnostic parameters are defined which enable to formulate general evaluation of technical condition of the engine based on standard online measurements of the exhaust gas temperature. A proposal is made to extend the parametric methods of diagnosing workspaces in turbocharged marine engines by analysing time-histories of enthalpy changes of the exhaust gas flowing to the turbocompressor turbine. Such a time-history can be worked out based on dynamic measurements of the exhaust gas temperature, performed using a specially designed sheathed thermocouple.

  15. Exhaust Gas Temperature Measurements in Diagnostics of Turbocharged Marine Internal Combustion Engines Part II Dynamic Measurements

    Directory of Open Access Journals (Sweden)

    Korczewski Zbigniew

    2016-01-01

    Full Text Available The second part of the article describes the technology of marine engine diagnostics making use of dynamic measurements of the exhaust gas temperature. Little-known achievements of Prof. S. Rutkowski of the Naval College in Gdynia (now: Polish Naval Academy in this area are presented. A novel approach is proposed which consists in the use of the measured exhaust gas temperature dynamics for qualitative and quantitative assessment of the enthalpy flux of successive pressure pulses of the exhaust gas supplying the marine engine turbocompressor. General design assumptions are presented for the measuring and diagnostic system which makes use of a sheathed thermocouple installed in the engine exhaust gas manifold. The corrected thermal inertia of the thermocouple enables to reproduce a real time-history of exhaust gas temperature changes.

  16. Structure of spinel at high temperature using in-situ XANES study at the Al and Mg K-edge

    Energy Technology Data Exchange (ETDEWEB)

    Ligny, D de [Universite Claude Bernard Lyon 1, LPCML, 69622 Villeurbanne (France); Neuville, D R [Physique des Mineraux et Magmas, Geochimie-Cosmochimie, CNRS-IPGP, 4 place Jussieu, 75005 Paris (France); Flank, A-M; Lagarde, P, E-mail: deligny@pcml.univ-lyon1.f [Synchrotron SOLEIL, L' Orme des Merisiers, Saint Aubin, 91192 France (France)

    2009-11-15

    We present structural information obtained on spinel at high temperature (298-2400 K) using in situ XANES at the Mg and Al K-edge. Spinel, {sup [4]}(Al{sub x},Mg{sub 1-x}){sup [6]}(Al{sub 2-x},Mg{sub x})O{sub 4}, with increasing temperature, show a substitution of Mg by Al and Al by Mg in their respective sites. This substitution corresponds to an inversion of the Mg and Al sites. Furthermore, both experiments at the Al and Mg K-edges are in good agreement with XANES calculation made using FDMNES code.

  17. Short Communication on "In-situ TEM ion irradiation investigations on U3Si2 at LWR temperatures"

    Science.gov (United States)

    Miao, Yinbin; Harp, Jason; Mo, Kun; Bhattacharya, Sumit; Baldo, Peter; Yacout, Abdellatif M.

    2017-02-01

    The radiation-induced amorphization of U3Si2 was investigated by in-situ transmission electron microscopy using 1 MeV Kr ion irradiation. Both arc-melted and sintered U3Si2 specimens were irradiated at room temperature to confirm the similarity in their responses to radiation. The sintered specimens were then irradiated at 350 °C and 550 °C up to 7.2 × 1015 ions/cm2 to examine their amorphization behavior under light water reactor (LWR) conditions. U3Si2 remains crystalline under irradiation at LWR temperatures. Oxidation of the material was observed at high irradiation doses.

  18. In situ high temperature MAS NMR study of the mechanisms of catalysis. Ethane aromatization on Zn-modified zeolite BEA.

    Science.gov (United States)

    Arzumanov, Sergei S; Gabrienko, Anton A; Freude, Dieter; Stepanov, Alexander G

    2009-04-01

    Ethane conversion into aromatic hydrocarbons over Zn-modified zeolite BEA has been analyzed by high-temperature MAS NMR spectroscopy. Information about intermediates (Zn-ethyl species) and reaction products (mainly toluene and methane), which were formed under the conditions of a batch reactor, was obtained by (13)C MAS NMR. Kinetics of the reaction, which was monitored by (1)H MAS NMR in situ at the temperature of 573K, provided information about the reaction mechanism. Simulation of the experimental kinetics within the frames of the possible kinetic schemes of the reaction demonstrates that a large amount of methane evolved under ethane aromatization arises from the stage of direct ethane hydrogenolysis.

  19. Lessons learned from the Febex in situ test: geochemical processes associated to the microbial degradation and gas generation

    International Nuclear Information System (INIS)

    Fernandez, A. M.; Sanchez, D.M.; Melon, A.; Mingarro, M.; Wieczorek, K.

    2012-01-01

    existence of gaps between the bentonite blocks, which favour the development and growth of inactive and dormant cells or spores belonging to the original bentonite. In this work, the observed geochemical and corrosion processes influenced both by organic matter degradation and micro-organisms in the 1:1 scale FEBEX in situ test (Grimsel, Switzerland) are described. This test consists of two heaters, simulating radioactive waste containers, emplaced in a horizontal gallery and surrounded by a highly compacted bentonite barrier. Samples from pore water, gases and bentonite (SHSDI-01: clay in contact with AISI 316L metal; S29 and BSBI-26: clay in contact with carbon steel) have been analysed. The samples were obtained during the test and the dismantling of the heater 1 after six years of experiment. The solid samples were analysed by XRD, SEM, XPS, FTIR, ATD-TG and chemical analysis; the water samples by IC and ICP-OES, and the gases by gas chromatography. Different geochemical processes have been detected as a function of the temperature and water content of the samples. When the water content is high, there are aerobic respiration and fermentation processes, anaerobic respiration with SO 4 2- as electron acceptor, and anaerobic production of methane with CO 2 as electron acceptor. In a first phase, both oxygen consumption and an increase of CH 4 and CO 2 is observed. Afterwards, there is a reduction of sulfates by SRB bacteria, which provokes corrosion processes. As a consequence, a precipitation of sulphurs, iron oxy-hydroxides and carbonates occurs, as well as H 2 generation. There is an increase of the iron content in the smectite and the neo-formation of zeolites. However this alteration is punctual and localized. The redox potential of the bentonite pore water was of -284 mV. When the temperature is high and water content is low, other processes take place

  20. Isothermal Time-Temperature-Precipitation Diagram for an Aluminum Alloy 6005A by In Situ DSC Experiments

    Directory of Open Access Journals (Sweden)

    Benjamin Milkereit

    2014-03-01

    Full Text Available Time-temperature-precipitation (TTP diagrams deliver important material data, such as temperature and time ranges critical for precipitation during the quenching step of the age hardening procedure. Although the quenching step is continuous, isothermal TTP diagrams are often applied. Together with a so-called Quench Factor Analysis, they can be used to describe very different cooling paths. Typically, these diagrams are constructed based on mechanical properties or microstructures after an interrupted quenching, i.e., ex situ analyses. In recent years, an in situ calorimetric method to record continuous cooling precipitation diagrams of aluminum alloys has been developed to the application level by our group. This method has now been transferred to isothermal experiments, in which the whole heat treatment cycle was performed in a differential scanning calorimeter. The Al-Mg-Si-wrought alloy 6005A was investigated. Solution annealing at 540 °C and overcritical quenching to several temperatures between 450 °C and 250 °C were followed by isothermal soaking. Based on the heat flow curves during isothermal soaking, TTP diagrams were determined. An appropriate evaluation method has been developed. It was found that three different precipitation reactions in characteristic temperature intervals exist. Some of the low temperature reactions are not accessible in continuous cooling experiments and require isothermal studies.

  1. In situ measurement of the junction temperature of light emitting diodes using a flexible micro temperature sensor.

    Science.gov (United States)

    Lee, Chi-Yuan; Su, Ay; Liu, Yin-Chieh; Fan, Wei-Yuan; Hsieh, Wei-Jung

    2009-01-01

    This investigation aimed to fabricate a flexible micro resistive temperature sensor to measure the junction temperature of a light emitting diode (LED). The junction temperature is typically measured using a thermal resistance measurement approach. This approach is limited in that no standard regulates the timing of data capture. This work presents a micro temperature sensor that can measure temperature stably and continuously, and has the advantages of being lightweight and able to monitor junction temperatures in real time. Micro-electro-mechanical-systems (MEMS) technologies are employed to minimize the size of a temperature sensor that is constructed on a stainless steel foil substrate (SS-304 with 30 μm thickness). A flexible micro resistive temperature sensor can be fixed between the LED chip and the frame. The junction temperature of the LED can be measured from the linear relationship between the temperature and the resistance. The sensitivity of the micro temperature sensor is 0.059 ± 0.004 Ω/°C. The temperature of the commercial CREE(®) EZ1000 chip is 119.97 °C when it is thermally stable, as measured using the micro temperature sensor; however, it was 126.9 °C, when measured by thermal resistance measurement. The micro temperature sensor can be used to replace thermal resistance measurement and performs reliably.

  2. In Situ Measurement of the Junction Temperature of Light Emitting Diodes Using a Flexible Micro Temperature Sensor

    Directory of Open Access Journals (Sweden)

    Wei-Jung Hsieh

    2009-06-01

    Full Text Available This investigation aimed to fabricate a flexible micro resistive temperature sensor to measure the junction temperature of a light emitting diode (LED. The junction temperature is typically measured using a thermal resistance measurement approach. This approach is limited in that no standard regulates the timing of data capture. This work presents a micro temperature sensor that can measure temperature stably and continuously, and has the advantages of being lightweight and able to monitor junction temperatures in real time. Micro-electro-mechanical-systems (MEMS technologies are employed to minimize the size of a temperature sensor that is constructed on a stainless steel foil substrate (SS-304 with 30 μm thickness. A flexible micro resistive temperature sensor can be fixed between the LED chip and the frame. The junction temperature of the LED can be measured from the linear relationship between the temperature and the resistance. The sensitivity of the micro temperature sensor is 0.059 ± 0.004 Ω/°C. The temperature of the commercial CREE® EZ1000 chip is 119.97 °C when it is thermally stable, as measured using the micro temperature sensor; however, it was 126.9 °C, when measured by thermal resistance measurement. The micro temperature sensor can be used to replace thermal resistance measurement and performs reliably.

  3. Effect of pairwise additivity on finite-temperature behavior of classical ideal gas

    Science.gov (United States)

    Shekaari, Ashkan; Jafari, Mahmoud

    2018-05-01

    Finite-temperature molecular dynamics simulations have been applied to inquire into the effect of pairwise additivity on the behavior of classical ideal gas within the temperature range of T = 250-4000 K via applying a variety of pair potentials and then examining the temperature dependence of a number of thermodynamical properties. Examining the compressibility factor reveals the most deviation from ideal-gas behavior for the Lennard-Jones system mainly due to the presence of both the attractive and repulsive terms. The systems with either attractive or repulsive intermolecular potentials are found to present no resemblance to real gases, but the most similarity to the ideal one as temperature rises.

  4. A design method to isothermalize the core of high-temperature gas-cooled reactors

    International Nuclear Information System (INIS)

    Takano, M.; Sawa, K.

    1987-01-01

    A practical design method is developed to isothermalize the core of block-type high-temperature gas-cooled reactors (HTGRs). Isothermalization plays an important role in increasing the design margin on fuel temperature. In this method, the fuel enrichment and the size and boron content of the burnable poison rod are determined over the core blockwise so that the axially exponential and radially flat power distribution are kept from the beginning to the end of core life. The method enables conventional HTGRs to raise the outlet gas temperature without increasing the maximum fuel temperature

  5. The early history of high-temperature helium gas-cooled nuclear power reactors

    International Nuclear Information System (INIS)

    Simnad, M.T.; California Univ., San Diego, La Jolla, CA

    1991-01-01

    The original concepts in the proposals for high-temperature helium gas-cooled power reactors by Farrington Daniels, during the decade 1944-1955, are summarized. The early research on the development of the helium gas-cooled power reactors is reviewed, and the operational experiences with the first generation of HTGRs are discussed. (author)

  6. Articulated Multimedia Physics, Lesson 14, Gases, The Gas Laws, and Absolute Temperature.

    Science.gov (United States)

    New York Inst. of Tech., Old Westbury.

    As the fourteenth lesson of the Articulated Multimedia Physics Course, instructional materials are presented in this study guide with relation to gases, gas laws, and absolute temperature. The topics are concerned with the kinetic theory of gases, thermometric scales, Charles' law, ideal gases, Boyle's law, absolute zero, and gas pressures. The…

  7. Effect of Temperature Shock and Inventory Surprises on Natural Gas and Heating Oil Futures Returns

    Science.gov (United States)

    Hu, John Wei-Shan; Lin, Chien-Yu

    2014-01-01

    The aim of this paper is to examine the impact of temperature shock on both near-month and far-month natural gas and heating oil futures returns by extending the weather and storage models of the previous study. Several notable findings from the empirical studies are presented. First, the expected temperature shock significantly and positively affects both the near-month and far-month natural gas and heating oil futures returns. Next, significant temperature shock has effect on both the conditional mean and volatility of natural gas and heating oil prices. The results indicate that expected inventory surprises significantly and negatively affects the far-month natural gas futures returns. Moreover, volatility of natural gas futures returns is higher on Thursdays and that of near-month heating oil futures returns is higher on Wednesdays than other days. Finally, it is found that storage announcement for natural gas significantly affects near-month and far-month natural gas futures returns. Furthermore, both natural gas and heating oil futures returns are affected more by the weighted average temperature reported by multiple weather reporting stations than that reported by a single weather reporting station. PMID:25133233

  8. Effect of temperature and α-irradiation on gas permeability for ...

    Indian Academy of Sciences (India)

    Unknown

    polymer membranes that help separate gas. In addition to the chemical composition, the transport properties are related to the main characteristics of copolymers like the glass transition temperature, crystallinity and crosslink- ing ratio. Gas diffusion through polymers is related to the activation energy (Pesiri et al 2003).

  9. Thermodynamics of high-temperature and high-density hadron gas by a numerical simulation

    Energy Technology Data Exchange (ETDEWEB)

    Sasaki, Nobuo; Miyamura, Osamu [Hiroshima Univ., Higashi-Hiroshima (Japan). Dept. of Physics

    1998-07-01

    We study thermodynamical properties of hot and dense hadronic gas an event generator URASiMA. In our results, the increase of temperature is suppressed. It indicates that hot and dense hadronic gas has a large specific heat at constant volume. (author)

  10. Quantitative explanation of some electron temperature profiles measured in situ in the high latitude ionospheric E-region

    International Nuclear Information System (INIS)

    Schlegel, K.; Oyama, Koh-ichiro; Hirao, Kunio

    1983-01-01

    E region electron temperature profiles obtained with a rocket experiment in the Antarctica are compared to theoretical electron temperatures calculated from a model. The main heat source in this model is the heating of the electron gas by unstable plasma waves. Very good agreement between both temperatures is obtained between 105 and 115 km altitude, where this heating mechanism is effective. The agreement is also good below this altitude range, after a refinement of the data analysis procedure for the measured temperatures. Several important consequences of the good agreement are pointed out. (author)

  11. Temperature-dependent gas transport and its correlation with kinetic ...

    Indian Academy of Sciences (India)

    2017-05-20

    May 20, 2017 ... have been made to see this trade-off relation at relatively higher temperature. It is found that selectivity ... acceptable due to low capital cost, less energy requirement ... in solubility, with increased permeability due to interac-.

  12. A method for calculating the gas volume proportions and inhalation temperature of inert gas mixtures allowing reaching normothermic or hypothermic target body temperature in the awake rat

    Directory of Open Access Journals (Sweden)

    Jacques H Abraini

    2017-01-01

    Full Text Available The noble gases xenon (Xe and helium (He are known to possess neuroprotective properties. Xe is considered the golden standard neuroprotective gas. However, Xe has a higher molecular weight and lower thermal conductivity and specific heat than those of nitrogen, the main diluent of oxygen (O2 in air, conditions that could impair or at least reduce the intrinsic neuroprotective properties of Xe by increasing the critical care patient's respiratory workload and body temperature. In contrast, He has a lower molecular weight and higher thermal conductivity and specific heat than those of nitrogen, but is unfortunately far less potent than Xe at providing neuroprotection. Therefore, combining Xe with He could allow obtaining, depending on the gas inhalation temperature and composition, gas mixtures with neutral or hypothermic properties, the latter being advantageous in term of neuroprotection. However, calculating the thermal properties of a mixture, whatever the substances – gases, metals, rubbers, etc. – is not trivial. To answer this question, we provide a graphical method to assess the volume proportions of Xe, He and O2 that a gas mixture should contain, and the inhalation temperature to which it should be administered to allow a clinician to maintain the patient at a target body temperature.

  13. Winter frost resistance of Pinus cembra measured in situ at the alpine timberline as affected by temperature conditions.

    Science.gov (United States)

    Buchner, Othmar; Neuner, Gilbert

    2011-11-01

    Winter frost resistance (WFR), midwinter frost hardening and frost dehardening potential of Pinus cembra L. were determined in situ by means of a novel low-temperature freezing system at the alpine timberline ecotone (1950 m a.s.l., Mt Patscherkofel, Innsbruck, Austria). In situ liquid nitrogen (LN₂)-quenching experiments should check whether maximum WFR of P. cembra belonging to the frost hardiest conifer group, being classified in US Department of Agriculture climatic zone 1, suffices to survive dipping into LN₂ (-196 °C). Viability was assessed in a field re-growth test. Maximum in situ WFR (LT₅₀) of leaves was frost hardening treatment (12 days at -20 °C followed by 3 days at -50 °C) to induce maximum WFR. Temperature treatments applied in the field significantly affected the actual WFR. In January a frost hardening treatment (21 days at -20 °C) led to a significant increase of WFR (buds: -62 °C to frost dehardening (buds: -32.6 °C to -10.2 °C; leaves: -32.7 to -16.4 °C) followed by significantly earlier bud swelling and burst in late winter. Strikingly, both temperature treatments, either increased air temperature (+10.1 °C) or increased soil temperature (+6.5 °C), were similarly effective. This high readiness to frost harden and deharden in winter in the field must be considered to be of great significance for future winter survival of P. cembra. Determination of WFR in field re-growth tests appears to be a valuable tool for critically judging estimates of WFR obtained on detached twigs in an ecological context.

  14. Minimization of steam requirements and enhancement of water-gas shift reaction with warm gas temperature CO2 removal

    Science.gov (United States)

    Siriwardane, Ranjani V; Fisher, II, James C

    2013-12-31

    The disclosure utilizes a hydroxide sorbent for humidification and CO.sub.2 removal from a gaseous stream comprised of CO and CO.sub.2 prior to entry into a water-gas-shift reactor, in order to decrease CO.sub.2 concentration and increase H.sub.2O concentration and shift the water-gas shift reaction toward the forward reaction products CO.sub.2 and H.sub.2. The hydroxide sorbent may be utilized for absorbtion of CO.sub.2 exiting the water-gas shift reactor, producing an enriched H.sub.2 stream. The disclosure further provides for regeneration of the hydroxide sorbent at temperature approximating water-gas shift conditions, and for utilizing H.sub.2O product liberated as a result of the CO.sub.2 absorption.

  15. Model simulation for high-temperature gas desulphurization processes

    Energy Technology Data Exchange (ETDEWEB)

    Tonini; Zaccagnini; Berg; Vitolo; Tartarelli; Zeppi (Struttura Informatica, Florence (Italy))

    1993-01-01

    Metal oxides such as zinc ferrite, zinc titanate and tin oxide have been identified as promising adsorbent materials in the removal of sulphur compounds from hot coal gas in power generation operations. A mathematical model for the sulfidation phase in fixed, moving and fluidised bed reactors has been developed. This paper presents kinetic models of spherical sorbent particles applicable to all reactor configurations and a mathematical model limited to the moving bed reactor. 10 refs., 5 figs.

  16. Program for aerodynamic performance tests of helium gas compressor model of the gas turbine high temperature reactor (GTHTR300)

    International Nuclear Information System (INIS)

    Takada, Shoji; Takizuka, Takakazu; Kunimoto, Kazuhiko; Yan, Xing; Itaka, Hidehiko; Mori, Eiji

    2003-01-01

    Research and development program for helium gas compressor aerodynamics was planned for the power conversion system of the Gas Turbine High Temperature Reactor (GTHTR300). The axial compressor with polytropic efficiency of 90% and surge margin more than 30% was designed with 3-dimensional aerodynamic design. Performance and surge margin of the helium gas compressor tends to be lower due to the higher boss ratio which makes the tip clearance wide relative to the blade height, as well as due to a larger number of stages. The compressor was designed on the basis of methods and data for the aerodynamic design of industrial open-cycle gas-turbine. To validate the design of the helium gas compressor of the GTHTR300, aerodynamic performance tests were planned, and a 1/3-scale, 4-stage compressor model was designed. In the tests, the performance data of the helium gas compressor model will be acquired by using helium gas as a working fluid. The maximum design pressure at the model inlet is 0.88 MPa, which allows the Reynolds number to be sufficiently high. The present study is entrusted from the Ministry of Education, Culture, Sports, Science and Technology of Japan. (author)

  17. Experimental Study of Natural Gas Temperature Effects on the Flame Luminosity and No Emission

    Directory of Open Access Journals (Sweden)

    S. M. Javadi

    2012-06-01

    Full Text Available The flame radiation enhancement in gas-fired furnaces significantly improves the thermal efficiency without significantly affecting the NOx emissions. In this paper, the effects of inlet natural gas preheating on the flame luminosity, overall boiler efficiency, and NO emission in a 120 kW boiler have been investigated experimentally. Flame radiation is measured by use of laboratory pyranometer with photovoltaic sensor. A Testo350XL gas analyzer is also used for measuring the temperature and combustion species. The fuel is preheated from the room temperature to 350°C. The experimental measurements show that the preheating of natural gas up to about 240°C has no considerable effect on the flame luminosity. The results show that increasing the inlet gas temperature from 240°C, abruptly increases the flame luminosity. This luminosity increase enhances the boiler efficiency and also causes significant reduction in flame temperature and NO emission. The results show that increasing the inlet gas temperature from 240°C to 300°C increases the flame luminous radiation by 60% and boiler efficiency by 20%; while the maximum flame temperature and the boiler NO emission show a 10% and 8% decrease respectively.

  18. Precise measurements of neutral gas temperature using Fiber Bragg Grating sensor in Argon capacitively coupled plasmas

    Science.gov (United States)

    Han, Daoman; Liu, Zigeng; Liu, Yongxin; Peng, Wei; Wang, Younian

    2016-09-01

    Neutral gas temperature was measured using Fiber Bragg Grating sensor (FBGs) in capacitively coupled argon plasmas. Thermometry is based on the thermal equilibrium between the sensor and neutral gases, which is found to become faster with increasing pressure. It is also observed that the neutral gas temperature is higher than the room temperature by 10 120 °depending on the experiental conditions, and gas temperature shows significant non-uniformity in space. In addition, radial profiles of neutral temperature at different pressures, resemble these of ion density, obtained by a floating double probe. Specifically, at low pressure, neutral gas temperature and ion density peak at the center of the reactor, while the peak appears at the edge of the electrode at higher pressure. The neutral gas heating is mainly caused by the elastic collisions of Ar + with neutral gas atoms in the sheath region after Ar + gaining a certain energy. This work was supported by the National Natural Science Foundation of China (NSFC) (Grants No. 11335004, 11405018, and 61137005).

  19. Experimental Evaluation of Cermet Turbine Stator Blades for Use at Elevated Gas Temperatures

    Science.gov (United States)

    Chiarito, Patrick T.; Johnston, James R.

    1959-01-01

    The suitability of cermets for turbine stator blades of a modified turbojet engine was determined at an average turbine-inlet-gas temperature of 2000 F. Such an increase in temperature would yield a premium in thrust from a service engine. Because the cermet blades require no cooling, all the available compressor bleed air could be used to cool a turbine made from conventional ductile alloys. Cermet blades were first run in 100-hour endurance tests at normal gas temperatures in order to evaluate two methods for mounting them. The elevated gas-temperature test was then run using the method of support considered best for high-temperature operation. After 52 hours at 2000 F, one of the group of four cermet blades fractured probably because of end loads resulting from thermal distortion of the spacer band of the nozzle diaphragm. Improved design of a service engine would preclude this cause of premature failure.

  20. Atomic and molecular hydrogen gas temperatures in a low-pressure helicon plasma

    Science.gov (United States)

    Samuell, Cameron M.; Corr, Cormac S.

    2015-08-01

    Neutral gas temperatures in hydrogen plasmas are important for experimental and modelling efforts in fusion technology, plasma processing, and surface modification applications. To provide values relevant to these application areas, neutral gas temperatures were measured in a low pressure (radiofrequency helicon discharge using spectroscopic techniques. The atomic and molecular species were not found to be in thermal equilibrium with the atomic temperature being mostly larger then the molecular temperature. In low power operation (measurements near a graphite target demonstrated localised cooling near the sample surface. The temporal evolution of the molecular gas temperature during a high power 1.1 ms plasma pulse was also investigated and found to vary considerably as a function of pressure.

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

    Energy Technology Data Exchange (ETDEWEB)

    Del Busto-Ramos, M.; Budzik, M.; Corvalan, C.; Morgan, M.; Nivens, D.; Applegate, B. [Purdue Univ., West Lafayette, IN (United States). Dept. of Food Science; Turco, R. [Purdue Univ., West Lafayette, IN (United States). Dept. of Agronomy

    2008-03-15

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

  2. Selective Sensing of Gas Mixture via a Temperature Modulation Approach: New Strategy for Potentiometric Gas Sensor Obtaining Satisfactory Discriminating Features.

    Science.gov (United States)

    Li, Fu-An; Jin, Han; Wang, Jinxia; Zou, Jie; Jian, Jiawen

    2017-03-12

    A new strategy to discriminate four types of hazardous gases is proposed in this research. Through modulating the operating temperature and the processing response signal with a pattern recognition algorithm, a gas sensor consisting of a single sensing electrode, i.e., ZnO/In₂O₃ composite, is designed to differentiate NO₂, NH₃, C₃H₆, CO within the level of 50-400 ppm. Results indicate that with adding 15 wt.% ZnO to In₂O₃, the sensor fabricated at 900 °C shows optimal sensing characteristics in detecting all the studied gases. Moreover, with the aid of the principle component analysis (PCA) algorithm, the sensor operating in the temperature modulation mode demonstrates acceptable discrimination features. The satisfactory discrimination features disclose the future that it is possible to differentiate gas mixture efficiently through operating a single electrode sensor at temperature modulation mode.

  3. Structural characterizaiton and gas reactions of small metal particles by high-resolution, in-situ TEM and TED

    Science.gov (United States)

    1984-01-01

    The existing in-situ transmission electron microscopy (TEM) facility was improved by adding a separately pumped mini-specimen chamber. The chamber contains wire-evaporation sources for three metals and a specimen heater for moderate substrate temperatures. A sample introduction device was constructed, installed, and tested, facilitating rapid introduction of a specimen into the mini-chamber while maintaining the background pressure in that chamber in the 10(-9) millibar range. Small particles and clusters of Pd, grown by deposition from the vapor phase in an in-situ TEM facility on amorphous and crystalline support films of alumina and on ultra-thin carbon films, were analyzed by conventional high-resolution TEM and image analysis in terms of detectability, number density, and size distribution. The smallest particles that could be detected and counted contained no more than 6 atoms; size determinations could be made for particles 1 nm in diameter. The influence of various oxygen plasma treatments, annealing treatments, and of increasing the substrate temperature during deposition was investigated. The TEM technique was employed to demonstrate that under otherwise identica l conditions the lattice parameter of Pd particles in the 1 to 2 nm size range and supported in random orientation on ex-situ prepared mica films is expanded by some 3% when compared to 5 nm size particles. It is believed that this expansion is neither a small-particle diffraction effect nor due to pseudomorphism, but that it is due to a annealing-induced transformation of the small as-deposited particles with predominantly composite crystal structures into larger particles with true f.c.c. structure and thus inherently smaller lattice parameter.

  4. Simulation for temperature changing investigation at RSG-GAS cooling system

    International Nuclear Information System (INIS)

    Utaja

    2002-01-01

    The RSG-GAS cooling system considers of primary and secondary system, is used for heat rejection from reactor core to the atmosphere. For temperature changing investigation cause by atmospherics condition changing or coolant flow rate changing, is more safe done by simulation. This paper describes the simulation for determine the RSG-GAS coolant temperature changing base on heat exchange and cooling tower characteristic. The simulation is done by computer programme running under WINDOWS 95 or higher. The temperature changing is based on heat transfer process on heat exchanger and cooling tower. The simulation will show the water tank temperature changing caused by the temperature and humidity of the atmosphere or by coolant flow rate changing. For example the humidity changing from 60% to 80% atmospherics temperature 30 oC and 32400 k Watt power will change the tank temperature from 37,97 oC to 40,03 oC

  5. Membrane steam reforming of natural gas for hydrogen production by utilization of medium temperature nuclear reactor

    International Nuclear Information System (INIS)

    Djati Hoesen Salimy

    2010-01-01

    The assessment of steam reforming process with membrane reactor for hydrogen production by utilizing of medium temperature nuclear reactor has been carried out. Difference with the conventional process of natural gas steam reforming that operates at high temperature (800-1000°C), the process with membrane reactor operates at lower temperature (~500°C). This condition is possible because the use of perm-selective membrane that separate product simultaneously in reactor, drive the optimum conversion at the lower temperature. Besides that, membrane reactor also acts the role of separation unit, so the plant will be more compact. From the point of nuclear heat utilization, the low temperature of process opens the chance of medium temperature nuclear reactor utilization as heat source. Couple the medium temperature nuclear reactor with the process give the advantage from the point of saving fossil fuel that give direct implication of decreasing green house gas emission. (author)

  6. In situ TEM and synchrotron characterization of U–10Mo thin specimen annealed at the fast reactor temperature regime

    International Nuclear Information System (INIS)

    Yun, Di; Mo, Kun; Mohamed, Walid; Ye, Bei; Kirk, Marquis A.; Baldo, Peter; Xu, Ruqing; Yacout, Abdellatif M.

    2015-01-01

    U–Mo metallic alloys have been extensively used for the Reduced Enrichment for Research and Test Reactors (RERTR) program, which is now known as the Office of Material Management and Minimization under the Conversion Program. This fuel form has also recently been proposed as fast reactor metallic fuels in the recent DOE Ultra-high Burnup Fast Reactor project. In order to better understand the behavior of U–10Mo fuels within the fast reactor temperature regime, a series of annealing and characterization experiments have been performed. Annealing experiments were performed in situ at the Intermediate Voltage Electron Microscope (IVEM-Tandem) facility at Argonne National Laboratory (ANL). An electro-polished U–10Mo alloy fuel specimen was annealed in situ up to 700 °C. At an elevated temperature of about 540 °C, the U–10Mo specimen underwent a relatively slow microstructure transition. Nano-sized grains were observed to emerge near the surface. At the end temperature of 700 °C, the near-surface microstructure had evolved to a nano-crystalline state. In order to clarify the nature of the observed microstructure, Laue diffraction and powder diffraction experiments were carried out at beam line 34-ID of the Advanced Photon Source (APS) at ANL. Phases present in the as-annealed specimen were identified with both Laue diffraction and powder diffraction techniques. The U–10Mo was found to recrystallize due to thermally-induced recrystallization driven by a high density of pre-existing dislocations. A separate in situ annealing experiment was carried out with a Focused Ion Beam processed (FIB) specimen. A similar microstructure transition occurred at a lower temperature of about 460 °C with a much faster transition rate compared to the electro-polished specimen. - Highlights: • TEM annealing experiments were performed in situ at the IVEM facility up to fast reactor temperature. • At 540 °C, the U-10Mo specimen underwent a slow microstructure transition

  7. In situ TEM and synchrotron characterization of U–10Mo thin specimen annealed at the fast reactor temperature regime

    Energy Technology Data Exchange (ETDEWEB)

    Yun, Di, E-mail: diyun1979@xjtu.edu.cn [Argonne National Laboratory, 9700 South Cass Avenue, Argonne, IL 60439 (United States); Xi' an Jiao Tong University, 28 Xian Ning West Road, Xi' an 710049 (China); Mo, Kun; Mohamed, Walid; Ye, Bei; Kirk, Marquis A.; Baldo, Peter; Xu, Ruqing; Yacout, Abdellatif M. [Argonne National Laboratory, 9700 South Cass Avenue, Argonne, IL 60439 (United States)

    2015-12-15

    U–Mo metallic alloys have been extensively used for the Reduced Enrichment for Research and Test Reactors (RERTR) program, which is now known as the Office of Material Management and Minimization under the Conversion Program. This fuel form has also recently been proposed as fast reactor metallic fuels in the recent DOE Ultra-high Burnup Fast Reactor project. In order to better understand the behavior of U–10Mo fuels within the fast reactor temperature regime, a series of annealing and characterization experiments have been performed. Annealing experiments were performed in situ at the Intermediate Voltage Electron Microscope (IVEM-Tandem) facility at Argonne National Laboratory (ANL). An electro-polished U–10Mo alloy fuel specimen was annealed in situ up to 700 °C. At an elevated temperature of about 540 °C, the U–10Mo specimen underwent a relatively slow microstructure transition. Nano-sized grains were observed to emerge near the surface. At the end temperature of 700 °C, the near-surface microstructure had evolved to a nano-crystalline state. In order to clarify the nature of the observed microstructure, Laue diffraction and powder diffraction experiments were carried out at beam line 34-ID of the Advanced Photon Source (APS) at ANL. Phases present in the as-annealed specimen were identified with both Laue diffraction and powder diffraction techniques. The U–10Mo was found to recrystallize due to thermally-induced recrystallization driven by a high density of pre-existing dislocations. A separate in situ annealing experiment was carried out with a Focused Ion Beam processed (FIB) specimen. A similar microstructure transition occurred at a lower temperature of about 460 °C with a much faster transition rate compared to the electro-polished specimen. - Highlights: • TEM annealing experiments were performed in situ at the IVEM facility up to fast reactor temperature. • At 540 °C, the U-10Mo specimen underwent a slow microstructure transition

  8. Kinetic Energy of a Trapped Fermi Gas at Finite Temperature

    Science.gov (United States)

    Grela, Jacek; Majumdar, Satya N.; Schehr, Grégory

    2017-09-01

    We study the statistics of the kinetic (or, equivalently, potential) energy for N noninteracting fermions in a 1 d harmonic trap of frequency ω at finite temperature T . Remarkably, we find an exact solution for the full distribution of the kinetic energy, at any temperature T and for any N , using a nontrivial mapping to an integrable Calogero-Moser-Sutherland model. As a function of temperature T and for large N , we identify (i) a quantum regime, for T ˜ℏω , where quantum fluctuations dominate and (ii) a thermal regime, for T ˜N ℏω , governed by thermal fluctuations. We show how the mean and the variance as well as the large deviation function associated with the distribution of the kinetic energy cross over from the quantum to the thermal regime as T increases.

  9. Determining pH at elevated pressure and temperature using in situ ¹³C NMR.

    Science.gov (United States)

    Surface, J Andrew; Wang, Fei; Zhu, Yanzhe; Hayes, Sophia E; Giammar, Daniel E; Conradi, Mark S

    2015-02-03

    We have developed an approach for determining pH at elevated pressures and temperatures by using (13)C NMR measurements of inorganic carbon species together with a geochemical equilibrium model. The approach can determine in situ pH with precision better than 0.1 pH units at pressures, temperatures, and ionic strengths typical of geologic carbon sequestration systems. A custom-built high pressure NMR probe was used to collect (13)C NMR spectra of (13)C-labeled CO2 reactions with NaOH solutions and Mg(OH)2 suspensions at pressures up to 107 bar and temperatures of 80 °C. The quantitative nature of NMR spectroscopy allows the concentration ratio [CO2]/[HCO3(-)] to be experimentally determined. This ratio is then used with equilibrium constants calculated for the specific pressure and temperature conditions and appropriate activity coefficients for the solutes to calculate the in situ pH. The experimentally determined [CO2]/[HCO3(-)] ratios agree well with the predicted values for experiments performed with three different concentrations of NaOH and equilibration with multiple pressures of CO2. The approach was then applied to experiments with Mg(OH)2 slurries in which the change in pH could track the dissolution of CO2 into solution, rapid initial Mg(OH)2 dissolution, and onset of magnesium carbonate precipitation.

  10. Electron temperature measurement of tungsten inert gas arcs

    International Nuclear Information System (INIS)

    Tanaka, Manabu; Tashiro, Shinichi

    2008-01-01

    In order to make clear the physical grounds of deviations from LTE (Local Thermodynamic Equilibrium) in the atmospheric helium TIG arcs electron temperature and LTE temperature obtained from electron number density were measured by using of line-profile analysis of the laser scattering method without an assumption of LTE. The experimental results showed that in comparison with the argon TIG arcs, the region where a deviation from LTE occurs tends to expand in higher arc current because the plasma reaches the similar state to LTE within shorter distance from the cathode due to the slower cathode jet velocity

  11. Statistically Enhanced Model of In Situ Oil Sands Extraction Operations: An Evaluation of Variability in Greenhouse Gas Emissions.

    Science.gov (United States)

    Orellana, Andrea; Laurenzi, Ian J; MacLean, Heather L; Bergerson, Joule A

    2018-02-06

    Greenhouse gas (GHG) emissions associated with extraction of bitumen from oil sands can vary from project to project and over time. However, the nature and magnitude of this variability have yet to be incorporated into life cycle studies. We present a statistically enhanced life cycle based model (GHOST-SE) for assessing variability of GHG emissions associated with the extraction of bitumen using in situ techniques in Alberta, Canada. It employs publicly available, company-reported operating data, facilitating assessment of inter- and intraproject variability as well as the time evolution of GHG emissions from commercial in situ oil sands projects. We estimate the median GHG emissions associated with bitumen production via cyclic steam stimulation (CSS) to be 77 kg CO 2 eq/bbl bitumen (80% CI: 61-109 kg CO 2 eq/bbl), and via steam assisted gravity drainage (SAGD) to be 68 kg CO 2 eq/bbl bitumen (80% CI: 49-102 kg CO 2 eq/bbl). We also show that the median emissions intensity of Alberta's CSS and SAGD projects have been relatively stable from 2000 to 2013, despite greater than 6-fold growth in production. Variability between projects is the single largest source of variability (driven in part by reservoir characteristics) but intraproject variability (e.g., startups, interruptions), is also important and must be considered in order to inform research or policy priorities.

  12. Vyrmethane. Progress report stage 5. In situ production of methane gas from peat

    Energy Technology Data Exchange (ETDEWEB)

    Martinell, R

    1982-12-01

    The Vyrmethane process means that bog water containing methane gas is circulated in a closed system and degassed. By this procedure the microbiological activity in the bog stimulates and new methane is produced and dissolved in the water, which circulates to a degassing station. From the degassing station the methane gas can be used for different purposes and the degassed water is infiltrated back in the peat bog. The degradation process is described by McCarty (Stanford 1964). According to this description all COD (Chemical Oxygen Demand) is supposed to be converted to methane. The Vyrmethane method does not reach this ideal result. Consequently the produced gas also includes carbon dioxide. The running cost for the process is mainly depending on the water circulation e.g. the demand of energy for the pumps. Consequently the result is propotional to the methane, which can be degassed from the circulated water. The results reached, so far, indicate that one added unit of mechanical energy is giving five units of heat energy in the form of methane gas. Better results are in prospect. This report, which is a following up of the pilot plants started up after 1978, is discussing the technical and economical conditions for the process. Consequently it is suggested that a number of full-scale prototype plants are built, studied further and that preparations are made for a demonstration stage including about 200 plants with geographical spreading out.

  13. Low temperature techniques for natural gas purification and LNG production: An energy and exergy analysis

    International Nuclear Information System (INIS)

    Baccanelli, Margaret; Langé, Stefano; Rocco, Matteo V.; Pellegrini, Laura A.; Colombo, Emanuela

    2016-01-01

    Highlights: • Low-temperature processes for of high CO_2 content natural gas have been modelled. • Energy and exergy analyses have been performed. • The Dual Pressure distillation scheme has the best thermodynamic performances. • There is a synergy between cryogenic natural gas purification and LNG production. - Abstract: Due to the rapid increase of the World’s primary energy demand of the last decades, low-temperature processes for the purification of natural gas streams with high carbon dioxide content has gained interest, since they allow to make profitable exploitation of low-quality gas reserves. Low temperature purification processes allow the direct production of a methane stream at high purity and at low-temperature, suitable conditions for the direct synergistic integration with natural gas cryogenic liquefaction processes, while CO_2 is obtained in liquid phase and under pressure. In this way, it can be pumped for transportation, avoiding significant compression costs as for classical CO_2 capture units (where carbon dioxide is discharged in gas phase and at atmospheric pressure), and further uses such as Enhanced Oil Recovery (EOR) or underground storage. In this paper, the three most common natural gas low-temperature purification techniques have been modelled and their performances have been evaluated through energy and exergy analyses. Specifically, the dual pressure low-temperature distillation process, the anti-sublimation process and a hybrid configuration have been considered. It is found that the dual pressure low-temperature distillation scheme reach the highest thermodynamic performances, resulting in the best values of exergy efficiency and equivalent methane requirements with respect to the other configurations. This is mainly due to the distributed temperature profile along a distillation column, resulting in a less irreversible heat exchanging process.

  14. In-Situ tensile testing of propellants in SEM: influence of temperature

    NARCIS (Netherlands)

    Di Benedetto, G.L.; Ramshorst, M.C.J.; Duvalois, W.; Hooijmeijer, P.; Heijden, A. van der

    2017-01-01

    A tensile module system placed within a Scanning Electron Microscope (SEM) was utilized to conduct insitu tensile testing of propellant samples. The tensile module system allows for real-time in-situ SEM analysis of the samples to determine the failure mechanism of the propellant material under

  15. Failure mechanisms in high temperature gas cooled reactor fuel particles

    International Nuclear Information System (INIS)

    Soo, P.; Uneberg, G.; Sabatini, R.L.; Schweitzer, D.G.

    1979-01-01

    BISO coated UO 2 and ThO 2 particles were heated to high temperatures to determine failure mechanisms during hypothetical loss of coolant scenarios. Rapid failure begins when the oxides are reduced to liquid carbides. Several failure mechanisms are applicable, ranging from hole and crack formation in the coatings to catastrophic particle disintegration

  16. Temperature dependence of the particle/gas partition coefficient: An application to predict indoor gas-phase concentrations of semi-volatile organic compounds

    Energy Technology Data Exchange (ETDEWEB)

    Wei, Wenjuan, E-mail: Wenjuan.Wei@cstb.fr [University of Paris-Est, Scientific and Technical Center for Building (CSTB), Health and Comfort Department, French Indoor Air Quality Observatory (OQAI), 84 Avenue Jean Jaurès, Champs sur Marne, 77447 Marne la Vallée Cedex 2 (France); Mandin, Corinne [University of Paris-Est, Scientific and Technical Center for Building (CSTB), Health and Comfort Department, French Indoor Air Quality Observatory (OQAI), 84 Avenue Jean Jaurès, Champs sur Marne, 77447 Marne la Vallée Cedex 2 (France); INSERM-U1085, Irset-Research Institute for Environmental and Occupational Health, Rennes (France); LERES-Environment and Health Research Laboratory (Irset and EHESP Technologic Platform), Rennes (France); Blanchard, Olivier [EHESP-School of Public Health, Sorbonne Paris Cité, Rennes (France); INSERM-U1085, Irset-Research Institute for Environmental and Occupational Health, Rennes (France); Mercier, Fabien [EHESP-School of Public Health, Sorbonne Paris Cité, Rennes (France); LERES-Environment and Health Research Laboratory (Irset and EHESP Technologic Platform), Rennes (France); INSERM-U1085, Irset-Research Institute for Environmental and Occupational Health, Rennes (France); Pelletier, Maud [EHESP-School of Public Health, Sorbonne Paris Cité, Rennes (France); INSERM-U1085, Irset-Research Institute for Environmental and Occupational Health, Rennes (France); Le Bot, Barbara [EHESP-School of Public Health, Sorbonne Paris Cité, Rennes (France); LERES-Environment and Health Research Laboratory (Irset and EHESP Technologic Platform), Rennes (France); INSERM-U1085, Irset-Research Institute for Environmental and Occupational Health, Rennes (France); and others

    2016-09-01

    The indoor gas-phase concentrations of semi-volatile organic compounds (SVOCs) can be predicted from their respective concentrations in airborne particles by applying the particle/gas partitioning equilibrium. The temperature used for partitioning is often set to 25 °C. However, indoor temperatures frequently differ from this reference value. This assumption may result in errors in the predicted equilibrium gas-phase SVOC concentrations. To improve the prediction model, the temperature dependence of the particle/gas partition coefficient must be addressed. In this paper, a theoretical relationship between the particle/gas partition coefficient and temperature was developed based on the SVOC absorptive mechanism. The SVOC particle/gas partition coefficients predicted by employing the derived theoretical relationship agree well with the experimental data retrieved from the literature (R > 0.93). The influence of temperature on the equilibrium gas-phase SVOC concentration was quantified by a dimensionless analysis of the derived relationship between the SVOC particle/gas partition coefficient and temperature. The predicted equilibrium gas-phase SVOC concentration decreased by between 31% and 53% when the temperature was lowered by 6 °C, while it increased by up to 750% when the indoor temperature increased from 15 °C to 30 °C. - Highlights: • A theoretical relationship between K{sub p} and temperature was developed. • The relationship was based on the SVOC absorptive mechanism. • The temperature impact was quantified by a dimensionless analysis.

  17. Conditions for lowering the flue gas temperature; Foerutsaettning foer saenkning av roekgastemperatur

    Energy Technology Data Exchange (ETDEWEB)

    Nordling, Magnus

    2012-02-15

    In heat and power production, the efficiency of the power plant increases the larger share of heat from the flue gas that is converted to power. However, this also implies that the temperature of the heat exchanging surfaces is lowered. If the temperature is lowered to a temperature below the dew point of the flue gas, this would result in condensation of the gas, which in turn elevates the risk of serious corrosion attack on the surfaces where condensation occurs. Thus, it is important to determine the dew point temperature. One way of determining the dew point temperature is to use data on composition of the fuel together with operation parameters of the plant, thus calculating the dew point temperature. However, this calculation of the dew point is not so reliable, especially if hygroscopic salts are present. Therefore, for safety reasons, the temperature of the flue gas is kept well above the dew point temperature. This results in lowered over-all efficiency of the plant. It could also be expected that for a certain plant, some construction materials under certain operation conditions would have corrosion characteristics that may allow condensation on the surface without severe and unpredictable corrosion attack. However, by only using operation parameters and fuel composition, it is even harder to predict the composition of the condensate at different operation temperatures than to calculate the dew point temperature. If the dew point temperature was known with a greater certainty, the temperature of the flue gas could be kept lower, just above the estimated value of the dew point, without any increased risk for condensation. If, in addition, also the resulting composition of the condensate at different temperatures below the dew point is known, it can be predicted if the construction materials of the flue gas channel were compatible with the formed condensate. If they are compatible, the flue gas temperature can be further lowered from the dew point

  18. MOTHER MK II: An advanced direct cycle high temperature gas reactor

    International Nuclear Information System (INIS)

    Hart, R.S.; Kendall, J.M.; Marsden, B.J.

    2003-01-01

    The MOTHER (MOdular Thermal HElium Reactor) power plant concepts employ high temperature gas reactors utilizing TRISO fuel, graphite moderator, and helium coolant, in combination with a direct Brayton cycle for electricity generation. The helium coolant from the reactor vessel passes through a Power Conversion Unit (PCU), which includes a turbine-generator, recuperator, precooler, intercooler and turbine-compressors, before being returned to the reactor vessel. The PCU substitutes for the reactor coolant system pumps and steam generators and most of the Balance Of Plant (BOP), including the steam turbines and condensers, employed by conventional nuclear power plants utilizing water cooled reactors. This provides a compact, efficient, and relatively simple plant configuration. The MOTHER MK I conceptual design, completed in the 1987 - 1989 time frame, was developed to economically meet the energy demands for extracting and processing heavy oil from the tar sands of western Canada. However, considerable effort was made to maximize the market potential beyond this application. Consistent with the remote and very high labour rate environment in the tar sands region, simplification of maintenance procedures and facilitation of 'change-out' in lieu of in situ repair was a design focus. MOTHER MK I had a thermal output of 288 MW and produced 120 MW electrical when operated in the electricity only production mode. An annular Prismatic reactor core was utilized, largely to minimize day-to-day operations activities. Key features of the power conversion system included two Power Conversion Units (144 MW th each), the horizontal orientation of all rotating machinery and major heat exchangers axes, high speed rotating machinery (17,030 rpm for the turbine-compressors and 10,200 rpm for the power turbine-generator), gas (helium) bearings for all rotating machinery, and solid state frequency conversion from 170 cps (at full power) to the grid frequency. Recognizing that the on

  19. Moderate temperature gas purification system: Application to high calorific coal-derived fuel

    Energy Technology Data Exchange (ETDEWEB)

    Kobayashi, M.; Shirai, H.; Nunokawa, M. [Central Research Institute of Electric Power Industry, Kanagawa (Japan)

    2008-01-15

    Simultaneous removal of dust, alkaline and alkaline-earth metals, halides and sulfur compounds is required to enlarge application of coal-derived gas to the high-temperature fuel cells and the fuel synthesis through chemical processing. Because high calorific fuel gas, such as oxygen-blown coal gas, has high carbon monoxide content, high-temperature (above 450{sup o}C) gas purification system is always subjected to the carbon deposition. We suggest moderate temperature (around 300{sup o}C) operation of the gas purification system to avoid the harmful disproportionation reaction and efficient removal of the various contaminants. Because the reaction rate is predominant to the performance of contaminant removal in the moderate temperature gas purification system, we evaluated the chemical removal processes; performance of the removal processes for halides and sulfur compounds was experimentally evaluated. The halide removal process with sodium aluminate sorbent had potential performance at around 300{sup o}C. The sulfur removal process with zinc ferrite sorbent was also applicable to the temperature range, though the reaction kinetics of the sorbent is essential to be approved.

  20. Moderate temperature gas purification system: application to high calorific coal derived fuel

    Energy Technology Data Exchange (ETDEWEB)

    M. Kobayashi; H. Shirai; M. Nunokawa [Central Research Institute of Electric Power Industry (CRIEPI), Kanagawa (Japan)

    2005-07-01

    Simultaneous removal of dust, alkaline and alkaline-earth metals, halides and sulfur compounds is required to enlarge application of coal-derived gas to the high temperature fuel cells and the fuel synthesis through chemical processing. Because high calorific fuel gas, such as oxygen-blown coal gas, has high carbon monoxide content, high temperature gas purification system is always subjected to the carbon deposition and slippage of contaminant of high vapor pressure. It was suggested that moderate temperature operation of the gas purification system is applied to avoid the harmful disproportionation reaction and efficient removal of the various contaminants. To establish the moderate temperature gas purification system, the chemical-removal processes where the reaction rate is predominant to the performance of contaminant removal should be evaluated. Performance of the removal processes for halides and sulfur compounds were experimentally evaluated. The halide removal process with sodium based sorbent had potential good performance at around 300{sup o}C. The sulfur removal process was also applicable to the temperature range, although the improvement of the sulfidation reaction rate is considered to be essential. 11 refs., 8 figs., 1 tab.

  1. High temperature, high pressure gas loop - the Component Flow Test Loop (CFTL)

    International Nuclear Information System (INIS)

    Gat, U.; Sanders, J.P.; Young, H.C.

    1984-01-01

    The high-pressure, high-temperature, gas-circulating Component Flow Test Loop located at Oak Ridge National Laboratory was designed and constructed utilizing Section III of the ASME Boiler and Pressure Vessel Code. The quality assurance program for operating and testing is also based on applicable ASME standards. Power to a total of 5 MW is available to the test section, and an air-cooled heat exchanger rated at 4.4 MW serves as heat sink. The three gas-bearing, completely enclosed gas circulators provide a maximum flow of 0.47 m 3 /s at pressures to 10.7 MPa. The control system allows for fast transients in pressure, power, temperature, and flow; it also supports prolonged unattended steady-state operation. The data acquisition system can access and process 10,000 data points per second. High-temperature gas-cooled reactor components are being tested

  2. Temperature-modulated direct thermoelectric gas sensors: thermal modeling and results for fast hydrocarbon sensors

    International Nuclear Information System (INIS)

    Rettig, Frank; Moos, Ralf

    2009-01-01

    Direct thermoelectric gas sensors are a promising alternative to conductometric gas sensors. For accurate results, a temperature modulation technique in combination with a regression analysis is advantageous. However, the thermal time constant of screen-printed sensors is quite large. As a result, up to now the temperature modulation frequency (20 mHz) has been too low and the corresponding principle-related response time (50 s) has been too high for many applications. With a special design, respecting the physical properties of thermal waves and the use of signal processing similar to a lock-in-amplifier, it is possible to achieve response times of about 1 s. As a result, direct thermoelectric gas sensors with SnO 2 as a gas-sensitive material respond fast and are reproducible to the propane concentration in the ambient atmosphere. Due to the path-independent behavior of the thermovoltage and the temperature, the measured thermopower of two sensors is almost identical

  3. Effects of Outside Air Temperature on Movement of Phosphine Gas in Concrete Elevator Bins

    Science.gov (United States)

    Studies that measured the movement and concentration of phosphine gas in upright concrete bins over time indicated that fumigant movement was dictated by air currents, which in turn, were a function of the difference between the average grain temperature and the average outside air temperature durin...

  4. Research and development for high temperature gas cooled reactor in Japan

    International Nuclear Information System (INIS)

    Taketani, K.

    1978-01-01

    The paper describes the current status of High Temperature Gas Cooled Reactor research and development work in Japan, with emphasis on the Experimental Very High Temperature Reactor (Exp. VHTR) to be built by Japan Atomic Energy Research Institute (JAERI) before the end of 1985. The necessity of construction of Exp. VHTR was explained from the points of Japanese energy problems and resources

  5. Plasmonic nanocomposite thin film enabled fiber optic sensors for simultaneous gas and temperature sensing at extreme temperatures.

    Science.gov (United States)

    Ohodnicki, Paul R; Buric, Michael P; Brown, Thomas D; Matranga, Christopher; Wang, Congjun; Baltrus, John; Andio, Mark

    2013-10-07

    Embedded sensors capable of operation in extreme environments including high temperatures, high pressures, and highly reducing, oxidizing and/or corrosive environments can make a significant impact on enhanced efficiencies and reduced greenhouse gas emissions of current and future fossil-based power generation systems. Relevant technologies can also be leveraged in a wide range of other applications with similar needs including nuclear power generation, industrial process monitoring and control, and aviation/aerospace. Here we describe a novel approach to embedded sensing under extreme temperature conditions by integration of Au-nanoparticle based plasmonic nanocomposite thin films with optical fibers in an evanescent wave absorption spectroscopy configuration. Such sensors can potentially enable simultaneous temperature and gas sensing at temperatures approaching 900-1000 °C in a manner compatible with embedded and distributed sensing approaches. The approach is demonstrated using the Au/SiO2 system deposited on silica-based optical fibers. Stability of optical fibers under relevant high temperature conditions and interactions with changing ambient gas atmospheres is an area requiring additional investigation and development but the simplicity of the sensor design makes it potentially cost-effective and may offer a potential for widespread deployment.

  6. The application of dynamic method for the temperature measurement of gas destruction in a plasma reactor

    International Nuclear Information System (INIS)

    Ryszard, Sarba

    2009-01-01

    This paper presents an experimental and theoretical study of the conversion of measuring probe temperature into hot gas temperature. The author gives a solution to the problem of a destruction temperature measurement in a plasma reactor. The temperature conversion is based on the thermodynamic similarity theory and statistical thermodynamics verification. The experimental measurements of the hot gas temperature have been made in the place where it considerably exceeds the melting point of the measuring probe material. The heat exchange phenomenon on the measuring probe's surface with the hot gas surrounding it is described by a forced convection equation. An analysis has been made of the heat flowing in and out of the measuring probe. The experimental part of the paper includes: an experimental measurement of gas velocity by means of luminous particles, a hot gas measurement for one distance from a nozzle and different diameters of the measuring probe, as well as different probing velocities. Numerical simulations have been made of the temperature distribution in a plasma jet. The experimental results are congruent with theoretical predictions. The aim of this research is a contribution to the structuring of a mathematical model of mass and energy balance in the processes of NHF 2 CL waste destruction.

  7. Temperature dependence of muonium reaction rates in the gas phase

    International Nuclear Information System (INIS)

    Fleming, D.G.; Garner, D.M.; Mikula, R.J.; British Columbia Univ., Vancouver

    1981-01-01

    A study of the temperature dependence of reaction rates has long been an important tool in establishing reaction pathways in chemical reactions. This is particularly true for the reactions of muonium (in comparison with those of hydrogen) since a measurement of the activation energy for chemical reaction is sensitive to both the height and the position of the potential barrier in the reaction plane. For collision controlled reactions, on the other hand, the reaction rate is expected to exhibit a weak T 1 sup(/) 2 dependence characteristic of the mean collision velocity. These concepts are discussed and their effects illustrated in a comparison of the chemical and spin exchange reaction rates of muonium and hydrogen in the temperature range approx.300-approx.500 K. (orig.)

  8. Gas Temperature and Radiative Heat Transfer in Oxy-fuel Flames

    DEFF Research Database (Denmark)

    Bäckström, Daniel; Johansson, Robert; Andersson, Klas

    This work presents measurements of the gas temperature, including fluctuations, and its influence on the radiative heat transfer in oxy-fuel flames. The measurements were carried out in the Chalmers 100 kW oxy-fuel test unit. The in-furnace gas temperature was measured by a suction pyrometer...... on the radiative heat transfer shows no effect of turbulence-radiation interaction. However, by comparing with temperature fluctuations in other flames it can be seen that the fluctuations measured here are relatively small. Further research is needed to clarify to which extent the applied methods can account...

  9. Gas temperature measurements in short duration turbomachinery test facilities

    Science.gov (United States)

    Cattafesta, L. N.; Epstein, A. H.

    1988-07-01

    Thermocouple rakes for use in short-duration turbomachinery test facilities have been developed using very fine thermocouples. Geometry variations were parametrically tested and showed that bare quartz junction supports (76 microns in diameter) yielded superior performance, and were rugged enough to survive considerable impact damage. Using very low cost signal conditioning electronics, temperature accuracies of 0.3 percent were realized yielding turbine efficiency measurements at the 1-percent level. Ongoing work to improve this accuracy is described.

  10. Insights into the dynamics of in situ gas hydrate formation and dissociation at the Bush Hill gas hydrate field, Gulf of Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Solomon, Evan A.; Kastner, Miriam; Robertson, Gretchen; Jannasch, Hans; Weinstein, Yishai

    2005-07-01

    Four newly designed flux meters called the MOSQUITO (Multiple Orifice Sampler and Quantitative Injection Tracer Observer), capable of measuring fluid flow rates and sampling pore fluid chemistry simultaneously, and two temperature loggers were deployed for 430 days adjacent to the Bush Hill hydrate mound in the northern Gulf of Mexico (GC 185). The main objective of the deployment was to understand how chemistry, temperature, and subsurface hydrology dynamically influence the growth and dissociation of the gas hydrate mound. The flux meters were deployed in a mussel field, in bacterial mats, in a tubeworm field, and at a background site approximately 100 m southwest of the hydrate mound. Results from the longterm chemical monitoring suggest that this system is not in dynamic equilibrium. Gas hydrate actively formed within the mussel field adjacent to the most active gas vent, in the tubeworm field, and at the background site. The hydrology is variable with upward flow rates ranging from 1-90 cm/yr and downward flow rates from 3-130 cm/yr. Two distinct hydrologic pulsing events were sampled across the three mound sites, which advect a fluid from depth that further stabilizes the gas hydrate deposit. The hydrogeochemistry at Bush Hill seems to be influenced by multiple mechanisms such as active formation of gas hydrate, fluid influx and outflux due to active venting of CH4 at transient methane seeps at and near the mound, local salt tectonics, and density driven convection. The fluxes of fluid, solutes, and methane may have a significant impact on the seafloor biochemical environment and the water column chemistry at Bush Hill. (Author)

  11. Rotational temperature measurement of NO gas using two-photon excitation spectrum

    Science.gov (United States)

    Ozaki, Tadao; Matsui, Yoshihiko; Ohsawa, Toshihiko

    1981-04-01

    The rotational temperature of nitric oxide gas has been measured by means of a single-beam two-photon excitation spectrum method using a pulsed continuously tunable dye laser. The nitric oxide gas was enclosed at about 40 Torr in a quartz cell which was put in an electric oven. The NO γ (0-0) band and R11+Q21 branches were used to obtain the two-photon excitation spectrum. The rotational temperatures were determined using the fact that molecules are distributed in the rotational levels according to the Boltzmann law. The temperature range was from room temperature to about 470 K. Observed temperatures were in good agreement with cell temperatures which were obtained by using a thermocouple.

  12. Preliminary study on helium turbomachine for high temperature gas-cooled reactor

    International Nuclear Information System (INIS)

    Chen Yihua; Wang Jie; Zhang Zuoyi

    2003-01-01

    In the high temperature gas-cooled reactor (HTGR), gas turbine cycle is a new concept in the field of nuclear power. It combines two technologies of HTGR and gas turbine cycle, which represent the state-of-the-art technologies of nuclear power and fossil fuel generation respectively. This approach is expected to improve safety and economy of nuclear power plant significantly. So it is a potential scheme with competitiveness. The heat-recuperated cycle is the main stream of gas turbine cycle. In this cycle, the work medium is helium, which is very different from the air, so that the design features of the helium turbomachine and combustion gas turbomachine are different. The paper shows the basic design consideration for the heat-recuperated cycle as well as helium turbomachine and highlights its main design features compared with combustion gas turbomachine

  13. Mean free path of nucleons in a Fermi gas at finite temperature

    International Nuclear Information System (INIS)

    Collins, M.T.; Griffin, J.J.

    1980-01-01

    The mean free path of a nucleon in a nuclear Fermi gas at finite temperature is calculated by utilizing the free nucleon-nucleon cross section modified to suppress final states excluded by the Pauli principle. The results agree with an earlier zero-temperature calculation but yield substantially smaller values than a previous finite-temperature analysis. The Fermi gas mean free paths are some two to four times shorter than those implied by phenomenological imaginary optical potentials, suggesting that the present Fermi gas model fails to adequately describe the physical processes determining the mean free path. Even so, the present results, taken as lower bounds on te mean free path, require temperatures of some 4.5 MeV before the mean free path of bound nucleons becomes as short as the nuclear diameter. It follows that very high excitation energies are prerequisite to any short mean free path assumption in nuclear heavy-ion collisions. (orig.)

  14. Method for determining waveguide temperature for acoustic transceiver used in a gas turbine engine

    Science.gov (United States)

    DeSilva, Upul P.; Claussen, Heiko; Ragunathan, Karthik

    2018-04-17

    A method for determining waveguide temperature for at least one waveguide of a transceiver utilized for generating a temperature map. The transceiver generates an acoustic signal that travels through a measurement space in a hot gas flow path defined by a wall such as in a combustor. The method includes calculating a total time of flight for the acoustic signal and subtracting a waveguide travel time from the total time of flight to obtain a measurement space travel time. A temperature map is calculated based on the measurement space travel time. An estimated wall temperature is obtained from the temperature map. An estimated waveguide temperature is then calculated based on the estimated wall temperature wherein the estimated waveguide temperature is determined without the use of a temperature sensing device.

  15. High-Temperature, High-Bandwidth Fiber Optic Pressure and Temperature Sensors for Gas Turbine Applications

    National Research Council Canada - National Science Library

    Fielder, Robert S; Palmer, Matthew E

    2003-01-01

    ..., and redesign compressor and turbine stages based on actual measurements. There currently exists no sensor technology capable of making pressure measurements in the critical hot regions of gas turbine engines...

  16. Combustion Temperature Effect of Diesel Engine Convert to Compressed Natural Gas Engine

    OpenAIRE

    Semin; Abdul R. Ismail; Rosli A. Bakar

    2009-01-01

    Effect of combustion temperature in the engine cylinder of diesel engine convert to Compressed Natural Gas (CNG) engine was presents in this study. The objective of this study was to investigate the engine cylinder combustion temperature effect of diesel engine convert to CNG engine on variation engine speed. Problem statement: The hypothesis was that the lower performance of CNG engine was caused by the effect of lower in engine cylinder temperature. Are the CNG engine is lower cylinder temp...

  17. High Temperature Metallic Seal Development For Aero Propulsion and Gas Turbine Applications

    Science.gov (United States)

    More, Greg; Datta, Amit

    2006-01-01

    A viewgraph presentation on metallic high temperature static seal development at NASA for gas turbine applications is shown. The topics include: 1) High Temperature Static Seal Development; 2) Program Review; 3) Phase IV Innovative Seal with Blade Alloy Spring; 4) Spring Design; 5) Phase IV: Innovative Seal with Blade Alloy Spring; 6) PHase IV: Testing Results; 7) Seal Seating Load; 8) Spring Seal Manufacturing; and 9) Other Applications for HIgh Temperature Spring Design

  18. [Investigation on the gas temperature of a plasma jet at atmospheric pressure by emission spectrum].

    Science.gov (United States)

    Li, Xue-chen; Yuan, Ning; Jia, Peng-ying; Niu, Dong-ying

    2010-11-01

    A plasma jet of a dielectric barrier discharge in coaxial electrode was used to produce plasma plume in atmospheric pressure argon. Spatially and temporally resolved measurement was carried out by photomultiplier tubes. The light emission signals both from the dielectric barrier discharge and from the plasma plume were analyzed. Furthermore, emission spectrum from the plasma plume was collected by high-resolution optical spectrometer. The emission spectra of OH (A 2sigma + --> X2 II, 307.7-308.9 nm) and the first negative band of N2+ (B2 sigma u+ --> X2 IIg+, 390-391.6 nm) were used to estimate the rotational temperature of the plasma plume by fitting the experimental spectra to the simulated spectra. The rotational temperature obtained is about 443 K by fitting the emission spectrum from the OH, and that from the first negative band of N2+ is about 450 K. The rotational temperatures obtained by the two method are consistent within 5% error band. The gas temperature of the plasma plume at atmospheric pressure was obtained because rotational temperature equals to gas temperature approximately in gas discharge at atmospheric pressure. Results show that gas temperature increases with increasing the applied voltage.

  19. Correlator of nucleon currents in finite temperature pion gas

    International Nuclear Information System (INIS)

    Eletsky, V.L.

    1990-01-01

    A retarded correlator of two currents with nucleon quantum numbers is calculated for finite temperature T π in the chiral limit. It is shown that for euclidean momenta the leading one-loop corrections arise from direct interaction of thermal pions with the currents. A dispersive representation for the correlator shows that this interaction smears the nucleon pole over a frequency interval with width ≅ T. This interaction does not change the exponential fall-off of the correlator in euclidean space but gives an O(T 2 /F 2 π ) contribution to the pre-exponential factor. (orig.)

  20. Anomalous low-temperature desorption from preirradiated rare gas solids

    International Nuclear Information System (INIS)

    Savchenko, E.V.; Gumenchuk, G.B.; Yurtaeva, E.M.; Belov, A.G.; Khyzhniy, I.V.; Frankowski, M.; Beyer, M.K.; Smith-Gicklhorn, A.M.; Ponomaryov, A.N.; Bondybey, V.E.

    2005-01-01

    The role for the exciton-induced defects in the stimulation of anomalous low-temperature desorption of the own lattice atoms from solid Ar and Ne preirradiated by an electron beam is studied. The free electrons from shallow traps-structural defects-was monitored by the measurements of a yield of the thermally induced exoelectron emission (TSEE). The reaction of recombination of self-trapped holes with electrons is considered as a source of energy needed for the desorption of atoms from the surface of preirradiated solids. A key part of the exciton-induced defects in the phenomenon observed is demonstrated

  1. Performing in-situ chemical oxidation with Fenton's Reagent at a former gas work in Rotterdam

    Energy Technology Data Exchange (ETDEWEB)

    Plaisier, W.; Pancras, T. [In-situ Technieken BV, Wageningen (Netherlands); Bennen, M.; Bouwhuis, E. [Public Works Rotterdam (Netherlands)

    2003-07-01

    In-Situ Technieken BV is the first company in the Netherlands to apply full-scale in-situ chemical oxidation (ISCO) by means of Fenton's reagent or permanganates. The use of ISCO for soil remediation purposes originated in the USA. After three years of practical experience in the Netherlands it can be stated that ISCO has become a proven technology for source area treatment in the Netherlands as well. We present the results of a pilot ISCO treatment program with Fenton's reagent that was performed at the former gas works facility 'Feyenoord'. The site is one of the largest gas works facilities built in Rotterdam. The former gas production activities have lead to severe pollution of soil and groundwater over an area of approximately 3 hectares. Both laboratory and field observations showed that it would be very difficult to execute an efficient Fenton's reagent ISCO treatment program at this specific site for the following reasons. First of all, the contamination consisting of tar and tar-related compounds is found in an anthropogenic (man-made) soil of 9 meter in thickness. Secondly, high contents of carbonates and organic material were found in the soils, which act as a scavenger for the hydroxyl free radical in a Fenton's reagent ISCO system. The pilot test was performed in two phases with an intermediate period of 2 months. The injection of totally 24 tonnes hydrogen peroxide (50%) was anticipated. Reactions of the reagents in the soil were very strong. The presence of old (forgotten) boreholes and an intensive drainage system, in combination with the aggressive reaction resulted in short-circuiting of reagents to the surface. Out of the proposed 24 tonnes of hydrogen peroxide (50%) only 14.5 tonnes were injected. This would have effect on the amount of contamination oxidized. Nevertheless, the oxidation had a significant effect on the soil contamination. A reduction of approximately 90% for PAH was obtained. Reduction was also

  2. Effect of changes in seafloor temperature and sea-level on gas hydrate stability

    Energy Technology Data Exchange (ETDEWEB)

    Garg, S.K.; Pritchett, W. [Science Applications International Corp., San Diego, CA (United States)

    2008-07-01

    Natural gas hydrates occur in oceanic sediments and in permafrost regions around the world. As a greenhouse gas, large amounts of methane released from the global hydrate reservoir would have a significant impact on Earth's climate. The role of methane released by hydrate dissociation in climate change is uncertain. However, changes in global climate such as glaciation and warming can destabilize the hydrates. During the last glacial maximum, the sea level dropped about 100 meters. It has been suggested that the sea-level fall was associated with gas hydrate instability and seafloor slumping. This paper investigated the effect of changes in seafloor temperature and sea level on gas hydrate stability and on gas venting at the seafloor. A one-dimensional numerical computer model (simulator) was developed to describe methane hydrate formation, decomposition, reformation, and distribution with depth below the seafloor in the marine environment. The simulator was utilized to model hydrate distributions at two sites, notably Blake Ridge, located offshore South Carolina and Hydrate Ridge, located off the coast of Oregon. The numerical models for the two sites were conditioned by matching the sulfate, chlorinity, and hydrate distribution measurements. The effect of changes in seafloor temperature and sea-level on gas hydrate stability were then investigated. It was concluded that for Blake Ridge, changes in hydrate concentration were small. Both the changes in seafloor temperature and sea-level led to a substantial increase in gas venting at the seafloor for Hydrate Ridge. 17 refs., 8 figs.

  3. Numerical simulation and geometry optimization of hot-gas mixing in lower plenum of high temperature gas-cooled reactor

    International Nuclear Information System (INIS)

    Wang Hang; Wang Jie; Laurien, E.

    2010-01-01

    The lower plenum in high temperature gas-cooled reactor was designed to mix the gas of different temperatures from the reactor core. Previous researches suggest the current geometry of the lower plenum to be improved for better mixing capability and lower pressure drop. In the presented work, a series of varied geometries were investigated with numerical simulation way. The choice of appropriate mesh type and size used in the geometry variation was discussed with the reference of experimental data. The original thin ribs in the current design were merged into thicker ones, and a junction located at the starting end of the outlet pipe was introduced. After comparing several potential optimization methods, an improved geometry was selected with the merged ribs increasing the pre-defined mixing coefficient and the junction reducing the pressure drop. Future work was discussed based on the simulation of real reactor case. The work shows a direction for design improvements of the lower plenum geometry. (authors)

  4. Sensor fabrication method for in situ temperature and humidity monitoring of light emitting diodes.

    Science.gov (United States)

    Lee, Chi-Yuan; Su, Ay; Liu, Yin-Chieh; Chan, Pin-Cheng; Lin, Chia-Hung

    2010-01-01

    In this work micro temperature and humidity sensors are fabricated to measure the junction temperature and humidity of light emitting diodes (LED). The junction temperature is frequently measured using thermal resistance measurement technology. The weakness of this method is that the timing of data capture is not regulated by any standard. This investigation develops a device that can stably and continually measure temperature and humidity. The device is light-weight and can monitor junction temperature and humidity in real time. Using micro-electro-mechanical systems (MEMS), this study minimizes the size of the micro temperature and humidity sensors, which are constructed on a stainless steel foil substrate (40 μm-thick SS-304). The micro temperature and humidity sensors can be fixed between the LED chip and frame. The sensitivities of the micro temperature and humidity sensors are 0.06±0.005 (Ω/°C) and 0.033 pF/%RH, respectively.

  5. In-situ electrochemical study of Zr1nb alloy corrosion in high temperature Li{sup +} containing water

    Energy Technology Data Exchange (ETDEWEB)

    Krausová, Aneta [University of Chemistry and Technology, Technická 3, 166 28 Prague 6 (Czech Republic); Macák, Jan, E-mail: macakj@vscht.cz [University of Chemistry and Technology, Technická 3, 166 28 Prague 6 (Czech Republic); Sajdl, Petr [University of Chemistry and Technology, Technická 3, 166 28 Prague 6 (Czech Republic); Novotný, Radek [JRC-IET, Westerduinveg 3, 1755 LE Petten (Netherlands); Renčiuková, Veronika [University of Chemistry and Technology, Technická 3, 166 28 Prague 6 (Czech Republic); Vrtílková, Věra [ÚJP a.s., Nad Kamínkou 1345, 156 10 Prague 5 (Czech Republic)

    2015-12-15

    Long-term in-situ corrosion tests were performed in order to evaluate the influence of lithium ions on the corrosion of zirconium alloy. Experiments were carried out in a high-pressure high-temperature loop (280 °C, 8 MPa) in a high concentration water solution of LiOH (70 and 200 ppm Li{sup +}) and in a simulated WWER primary coolant environment. The kinetic parameters characterising the oxidation process have been explored using in-situ electrochemical impedance spectroscopy and slow potentiodynamic polarization. Also, a suitable equivalent circuit was suggested, which would approximate the impedance characteristics of the corrosion of Zr–1Nb alloy. The Mott–Schottky approach was used to determine the semiconducting character of the passive film. - Highlights: • Zr1Nb alloy was tested in WWER coolant and in LiOH solutions at 280 °C. • Corrosion rates were estimated in-situ from electrochemical data. • Electrochemical data agreed well with weight gains and metallography data. • Increase of corrosion rate in LiOH appeared after short exposure (300–500 h). • Very high donor densities (1.1–1.2 × 10{sup 20} cm{sup −3}) of Zr oxide grown in LiOH were found.

  6. Electrochemical activation of Li2MnO3 at elevated temperature investigated by in situ Raman microscopy

    International Nuclear Information System (INIS)

    Lanz, Patrick; Villevieille, Claire; Novák, Petr

    2013-01-01

    Layered-layered oxides of the type xLi 2 MnO 3 ·(1 − x)LiMO 2 (M = Mn, Ni, Co) have been postulated to contain Li 2 MnO 3 domains which, upon electrochemical activation, give rise to a characteristic potential plateau at 4.5 V vs. Li + /Li. To improve our understanding of the complex reaction mechanisms at play, we applied in situ Raman microscopy to investigate the constituent Li 2 MnO 3 . Li 2 MnO 3 synthesised via a two-step solid-state reaction was characterised by scanning electron microscopy and X-ray diffraction. Preliminary electrochemical tests and ex situ Raman microscopy showed the need for elevated temperatures to achieve activation. For the first time, in situ Raman microscopy (at 50 °C) confirmed the activation of Li 2 MnO 3 . The main signal at 615 cm −1 shifted to higher wavenumbers upon charging. After reaching 4.4 V vs. Li + /Li, this shift grew significantly, which is in good agreement with the onset of the potential plateau in both Li 2 MnO 3 and xLi 2 MnO 3 ·(1 − x)LiMO 2 , and is assigned to the partial formation of a spinel-like phase

  7. High-temperature gas-cooled reactor: reformer application study

    International Nuclear Information System (INIS)

    1980-12-01

    This Application Study evaluates the HTGR-R with a core outlet temperature of 850 0 C as a near-term Lead Project and as a vehicle to long-term HTGR Program objectives. The scope of this effort included evaluation of the HTGR-R technology, evaluation of potential HTGR-R markets, assessment of the economics of commercial HTGR-R plants, and the evaluation of the program scope and expenditures necessary to establish HTGR-R technology through the completion of the Lead Project. In order to properly assess the potential of the HTGR-R and the suitability of the HTGR-R as a Lead Project, additional work must be performed before a final judgment is rendered. Design trade-off studies and alternative applications must be investigated to determine if a commercial potential exists for the HTGR-R at 850 0 C. If commercial incentives are only identified for the HTGR-R with core outlet temperatures greater than 850 0 C, the design and development program duration and cost and the demonstration path for the HTGR-R must be reassessed

  8. Gas cooled thermal reactors with high temperatures (VHTR)

    International Nuclear Information System (INIS)

    Bouchter, J.C.; Dufour, P.; Guidez, J.; Latge, C.; Renault, C.; Rimpault, G.; Vasile, A.

    2014-01-01

    VHTR is one of the 6 concepts retained for the 4. generation of nuclear reactors, it is an upgraded version of the HTR-type reactor (High Temperature Reactors). 5 HTR reactors were operated in the world in the eighties, now 2 experimental HTR are working in China and Japan and 2 HTR with an output power of 100 MWe are being built in China. The purpose of the VHTR is to provide an helium at very high temperatures around 1000 Celsius degrees that could be used directly in a thermochemical way to produce hydrogen for instance. HTR reactors are interesting in terms of safety but it does not optimise the consumption of uranium and the production of wastes. This article presents a brief historical account of HTR-type reactors and their main design and safety features. The possibility of using HTR to burn plutonium is also presented as well as the possibility of closing the fuel cycle and of using thorium-uranium fuel. (A.C.)

  9. Stability of test environments for performance evaluation of materials for the modular high-temperature gas-cooled reactor

    International Nuclear Information System (INIS)

    Edgemon, G.L.; Wilson, D.F.; Bell, G.E.C.

    1993-01-01

    Stability of the primary helium-based coolant test gas for use in performance ests of materials for the Modular High-Temperature Gas-Cooled Reactor (MHTGR) was determined. Results of tests of the initial gas chemistry from General Atomics (GA) at elevated temperatures, and the associated results predicted by the SOLGASMIX trademark modelling package are presented. Results indicated that for this gas composition and at flow rates obtainable in the test loop, 466 ± 24C is the highest temperature that can be maintained without significantly altering the specified gas chemistry. Four additional gas chemistries were modelled using SOLGASMIX trademark

  10. Gas-liquid interface of room-temperature ionic liquids.

    Science.gov (United States)

    Santos, Cherry S; Baldelli, Steven

    2010-06-01

    The organization of ions at the interface of ionic liquids and the vacuum is an ideal system to test new ideas and concepts on the interfacial chemistry of electrolyte systems in the limit of no solvent medium. Whilst electrolyte systems have numerous theoretical and experimental methods used to investigate their properties, the ionic liquids are relatively new and our understanding of the interfacial properties is just beginning to be explored. In this critical review, the gas-liquid interface is reviewed, as this interface does not depend on the preparation of another medium and thus produces a natural interface. The interface has been investigated by sum frequency generation vibrational spectroscopy and ultra-high vacuum techniques. The results provide a detailed molecular-level view of the surface composition and structure. These have been complemented by theoretical studies. The combinations of treatments on this interface are starting to provide a somewhat convergent description of how the ions are organized at this neat interface (108 references).

  11. Mechanical Property and Its Comparison of Superalloys for High Temperature Gas Cooled Reactor

    International Nuclear Information System (INIS)

    Kim, Woo Gon; Kim, D. W.; Ryu, W. S.; Han, C. H.; Yoon, J. H.; Chang, J.

    2005-01-01

    Since structural materials for high temperature gas cooled reactor are used during long period in nuclear environment up to 1000 .deg. C, it is important to have good properties at elevated temperature such as mechanical properties (tensile, creep, fatigue, creep-fatigue), microstructural stability, interaction between metal and gas, friction and wear, hydrogen and tritium permeation, irradiation behavior, corrosion by impurity in He. Thus, in order to select excellent materials for the high temperature gas cooled reactor, it is necessary to understand the material properties and to gather the data for them. In this report, the items related to material properties which are needed for designing the high temperature gas cooled reactor were presented. Mechanical properties; tensile, creep, and fatigue etc. were investigated for Haynes 230, Hastelloy-X, In 617 and Alloy 800H, which can be used as the major structural components, such as intermediate heat exchanger (IHX), hot duct and piping and internals. Effect of He and irradiation on these structural materials was investigated. Also, mechanical properties; physical properties, tensile properties, creep and creep crack growth rate were compared for them, respectively. These results of this report can be used as important data to select superior materials for high temperature gas reactor

  12. The Validity of 21 cm Spin Temperature as a Kinetic Temperature Indicator in Atomic and Molecular Gas

    Energy Technology Data Exchange (ETDEWEB)

    Shaw, Gargi [Dept. of Physics, UM-DAE Centre for Excellence in Basic Sciences, University of Mumbai, Mumbai 400098 (India); Ferland, G. J. [Department of Physics and Astronomy, University of Kentucky, Lexington, KY 40506 (United States); Hubeny, I., E-mail: gargishaw@gmail.com, E-mail: gary@uky.edu, E-mail: hubeny@as.arizona.edu [Steward Observatory, University of Arizona, Tucson, AZ 85721 (United States)

    2017-07-10

    The gas kinetic temperature ( T {sub K} ) of various interstellar environments is often inferred from observations that can deduce level populations of atoms, ions, or molecules using spectral line observations; H i 21 cm is perhaps the most widely used, and has a long history. Usually the H i 21 cm line is assumed to be in thermal equilibrium and the populations are given by the Boltzmann distribution. A variety of processes, many involving Ly α , can affect the 21 cm line. Here we show how this is treated in the spectral simulation code Cloudy, and present numerical simulations of environments where this temperature indicator is used, with a detailed treatment of the physical processes that determine level populations within H{sup 0}. We discuss situations where this temperature indicator traces T {sub K}, cases where it fails, as well as the effects of Ly α pumping on the 21 cm spin temperature. We also show that the Ly α excitation temperature rarely traces the gas kinetic temperature.

  13. High-Temperature Phase Equilibria of Duplex Stainless Steels Assessed with a Novel In-Situ Neutron Scattering Approach

    Science.gov (United States)

    Pettersson, Niklas; Wessman, Sten; Hertzman, Staffan; Studer, Andrew

    2017-04-01

    Duplex stainless steels are designed to solidify with ferrite as the parent phase, with subsequent austenite formation occurring in the solid state, implying that, thermodynamically, a fully ferritic range should exist at high temperatures. However, computational thermodynamic tools appear currently to overestimate the austenite stability of these systems, and contradictory data exist in the literature. In the present work, the high-temperature phase equilibria of four commercial duplex stainless steel grades, denoted 2304, 2101, 2507, and 3207, with varying alloying levels were assessed by measurements of the austenite-to-ferrite transformation at temperatures approaching 1673 K (1400 °C) using a novel in-situ neutron scattering approach. All grades became fully ferritic at some point during progressive heating. Higher austenite dissolution temperatures were measured for the higher alloyed grades, and for 3207, the temperature range for a single-phase ferritic structure approached zero. The influence of temperatures in the region of austenite dissolution was further evaluated by microstructural characterization using electron backscattered diffraction of isothermally heat-treated and quenched samples. The new experimental data are compared to thermodynamic calculations, and the precision of databases is discussed.

  14. Tensile testing of materials at high temperatures above 1700 °C with in situ synchrotron X-ray micro-tomography

    International Nuclear Information System (INIS)

    Haboub, Abdel; Nasiatka, James R.; MacDowell, Alastair A.; Bale, Hrishikesh A.; Cox, Brian N.; Marshall, David B.; Ritchie, Robert O.

    2014-01-01

    A compact ultrahigh temperature tensile testing instrument has been designed and fabricated for in situ x-ray micro-tomography using synchrotron radiation at the Advanced Light Source, Lawrence Berkeley National Laboratory. It allows for real time x-ray micro-tomographic imaging of test materials under mechanical load at temperatures up to 2300 °C in controlled environments (vacuum or controlled gas flow). Sample heating is by six infrared halogen lamps with ellipsoidal reflectors arranged in a confocal configuration, which generates an approximately spherical zone of high heat flux approximately 5 mm in diameter. Samples are held between grips connected to a motorized stage that loads the samples in tension or compression with forces up to 2.2 kN. The heating chamber and loading system are water-cooled for thermal stability. The entire instrument is mounted on a rotation stage that allows stepwise recording of radiographs over an angular range of 180°. A thin circumferential (360°) aluminum window in the wall of the heating chamber allows the x-rays to pass through the chamber and the sample over the full angular range. The performance of the instrument has been demonstrated by characterizing the evolution of 3D damage mechanisms in ceramic composite materials under tensile loading at 1750 °C

  15. Decrease in lower level density due to cooling of gas temperature by thermal dissociation of hydrogen in copper vapor laser

    International Nuclear Information System (INIS)

    Watanabe, Ikuo; Hayashi, Kazuo; Iseki, Yasushi; Suzuki, Setsuo; Noda, Etsuo; Morimiya, Osamu

    1995-01-01

    A gas temperature calculation is carried out in the copper vapor laser (CVL) with a beam diameter of 80 mm in the case of H 2 addition into the Ne buffer gas. The on-axis gas temperature decreases to 2800K with 1% concentration of H 2 , whereas the gas temperature is 3400K without H 2 . The on-axis lower level density decreases due to the cooling of the gas temperature. This decrease in the lower level density is thought to bring about a non annular beam profile in the case of H 2 addition. (author)

  16. Corrosion of high temperature alloys in the primary circuit helium of high temperature gas cooled reactors. Pt. 2

    International Nuclear Information System (INIS)

    Quadakkers, W.J.

    1985-01-01

    The reactive impurities H 2 O, CO, H 2 and CH 4 which are present in the primary coolant helium of high temperature gas-cooled reactors can cause scale formation, internal oxidation and carburization or decarburization of the high temperature structural alloys. In Part 1 of this contribution a theoretical model was presented, which allows the explanation and prediction of the observed corrosion effects. The model is based on a classical stability diagram for chromium, modified to account for deviations from equilibrium conditions caused by kinetic factors. In this paper it is shown how a stability diagram for a commercial alloy can be constructed and how this can be used to correlate the corrosion results with the main experimental parameters, temperature, gas and alloy composition. Using the theoretical model and the presented experimental results, conditions are derived under which a protective chromia based surface scale will be formed which prevents a rapid transfer of carbon between alloy and gas atmosphere. It is shown that this protective surface oxide can only be formed if the carbon monoxide pressure in the gas exceeds a critical value. Psub(CO), which depends on temperature and alloy composition. Additions of methane only have a limited effect provided that the methane/water ratio is not near to, or greater than, a critical value of around 100/1. The influence of minor alloying additions of strong oxide forming elements, commonly present in high temperature alloys, on the protective properties of the chromia surface scales and the kinetics of carbon transfer is illustrated. (orig.) [de

  17. In Situ Insight into Reversible O2 Gas-Solid Reactions

    DEFF Research Database (Denmark)

    Wegeberg, Christina

    2016-01-01

    Non-porous crystalline solids containing a series of cationic tetracobalt complexes reversibly, selectively and stoichiometrically chemisorb dioxygen in temperature/O2 partial pressure induced processes involving the oxidation of cobalt with concurrent reduction of two equivalents of sorbed O2 to...

  18. In-situ transmission electron microscopy study of ion-irradiated copper : comparison of the temperature dependence of cascade collapse in FCC- and BCC- metals.

    Energy Technology Data Exchange (ETDEWEB)

    Daulton, T. L.

    1998-10-23

    The kinetics which drive cascade formation and subsequent collapse into point-defect clusters is investigated by analyzing the microstructure produced in situ by low fluence 100 keV Kr ion irradiations of fcc-Cu over a wide temperature range (18-873 K). The yield of collapsed point-defect clusters is demonstrated unequivocally to be temperature dependent, remaining approximately constant up to lattice temperatures of 573 K and then abruptly decreasing with increasing temperature. This drop in yield is not caused by defect loss during or following ion irradiation. This temperature dependence can be explained by a thermal spike effect. These in-situ yield measurements are compared to previous ex-situ yield measurements in fcc-Ni and bcc-Mo.

  19. In situ transmission electron microscopy study of ion-irradiated copper: comparison of the temperature dependence of cascade collapse in fcc- and bcc-metals

    International Nuclear Information System (INIS)

    Daulton, T.L.; Kirk, M.A.; Rehn, L.E.

    2000-01-01

    The kinetics which drive cascade formation and subsequent collapse into point-defect clusters are investigated by analyzing the microstructure produced in situ by low fluence 100 keV Kr ion irradiations of fcc-Cu over a wide temperature range (18-873 K). The yield of collapsed point-defect clusters is demonstrated unequivocally to be temperature dependent, remaining approximately constant up to lattice temperatures of 573 K and then abruptly decreasing with increasing temperature. This drop in yield is not caused by defect loss during or following ion irradiation. In addition, this temperature dependence can be explained by a thermal spike effect. These in situ yield measurements are compared to previous ex situ yield measurements in fcc-Ni and bcc-Mo

  20. Improved spacers for high temperature gas-cooled heat exchangers

    Energy Technology Data Exchange (ETDEWEB)

    Nordstroem, L A [Swiss Federal Institute for Reactor Research, Wuerenlingen (Switzerland)

    1984-07-01

    Experimental and analytical investigations in the field of heat exchanger thermohydraulics have been performed at EIR for many years, Basic studies have been carried out on heat transfer and pressure loss for tube bundles of different geometries and tube surfaces. As a part of this overall R+D programme for heat exchangers, investigations have been carried out on spacer pressure loss in bundles with longitudinal flow. An analytical spacer pressure loss model was developed which could handle different types of subchannel within the bundle. The model has been evaluated against experiments, using about 25 spacers of widely differing geometries. In a gas-cooled reactor it is important to keep the pressure loss over the primary circuit heat exchangers to a minimum. In exchangers with grid spacers these contribute a significant proportion of the overall bundle losses. For example, in the HHT Recuperator, with a shell-side pressure loss of 3.5 % of the inlet pressure, the spacers cause about one half of this loss. Reducing the loss to, say, 2.5 % results in an overall increase in plant efficiency by more than 1 % - a significant improvement Preliminary analysis identified 5 geometries in particular which were chosen for experimental evaluation as part of a joint project with the SULZER Company, to develop a low pressure-loss spacer for HHT heat exchangers (longitudinal counter-flow He/He and He/H{sub 2}O designs). The aim of the tests was to verify the low pressure-loss characteristics of these spacer grid types, as well as the quality of the results calculated by the computer code analytical model. The experimental and analytical results are compared in this report.

  1. Exploitation of low-temperature energy sources from cogeneration gas engines

    International Nuclear Information System (INIS)

    Caf, A.; Urbancl, D.; Trop, P.; Goricanec, D.

    2016-01-01

    This paper describes an original and innovative technical solution for exploiting low-temperature energy sources from cogeneration gas reciprocating engines installed within district heating systems. This solution is suitable for those systems in which the heat is generated by the use of reciprocating engines powered by gaseous fuel for combined heat and power production. This new technical solution utilizes low-temperature energy sources from a reciprocating gas engine which is used for a combined production of heat and power. During the operation of the cogeneration system low-temperature heat is released, which can be raised to as much as 85 °C with the use of a high-temperature heat-pump, thus enabling a high-temperature regime for heating commercial buildings, district heating or in industrial processes. In order to demonstrate the efficiency of utilizing low-temperature heat sources in the cogeneration system, an economic calculation is included which proves the effectiveness and rationality of integrating high-temperature heat-pumps into new or existing systems for combined heat and power production with reciprocating gas engines. - Highlights: • The use of low-temperature waste heat from the CHP is described. • Total energy efficiency of the CHP can be increased to more than 103.3%. • Low-temperature heat is exploited with high-temperature heat pump. • High-temperature heat pump allows temperature rise to up to 85 °C. • Exploitation of low-temperature waste heat increases the economics of the CHP.

  2. The world trends of high temperature gas-cooled reactors and the mode of utilization

    International Nuclear Information System (INIS)

    Ishikawa, Hiroshi; Shimokawa, Jun-ichi

    1974-01-01

    After a long period of research and development, high temperature gas-cooled reactors are going to enter the practical stage. The combination of a HTGR with a closed cycle helium gas turbine is advantageous in thermal efficiency, reduction of environmental impact and economy. In recent years, the direct utilization of nuclear heat energy in industries has been attracting interest. The multi-purpose utilization of high temperature gas-cooled reactors is thus now the world trend. Reviewing the world developments in this field, the following matters are described: (1) development of HTGRs in the U.K., West Germany, France and the United States; (2) development of He gas turbine, etc. in West Germany; and (3) multi-purpose utilization of HTGRs in West Germany and Japan. (Mori, K.)

  3. A Comparison of Thermal Models for Temperature Profiles in Gas-Lift Wells

    Directory of Open Access Journals (Sweden)

    Langfeng Mu

    2018-02-01

    Full Text Available Gas lift is a simple, reliable artificial lift method which is frequently used in offshore oil field developments. In order to enhance the efficiency of production by gas lift, it is vital to exactly predict the distribution of temperature-field for fluid within the wellbore. A new mechanistic model is developed for computing flowing fluid temperature profiles in both conduits simultaneously for a continuous-flow gas-lift operation. This model assumes steady heat transfer in the formation, as well as steady heat transfer in the conduits. A micro-units discrete from the wellbore, whose heat transfer process is analyzed and whose heat transfer equation is set up according to the law of conservation of energy. A simplified algebraic solution to our model is conducted to analyze the temperature profile. Sensitivity analysis was conducted with the new model. The results indicate that mass flow rate of oil and the tubing overall heat transfer coefficient are the main factors that influence the temperature distribution inside the tubing and that the mass flow rate of oil is the main factor affecting temperature distribution in the annulus. Finally, the new model was tested in three various wells and compared with other models. The results showed that the new model is more accurate and provides significant references for temperature prediction in gas lift well.

  4. Development and industrial application of catalyzer for low-temperature hydrogenation hydrolysis of Claus tail gas

    Directory of Open Access Journals (Sweden)

    Honggang Chang

    2015-10-01

    Full Text Available With the implementation of more strict national environmental protection laws, energy conservation, emission reduction and clean production will present higher requirements for sulfur recovery tail gas processing techniques and catalyzers. As for Claus tail gas, conventional hydrogenation catalyzers are gradually being replaced by low-temperature hydrogenation catalyzers. This paper concentrates on the development of technologies for low-temperature hydrogenation hydrolysis catalyzers, preparation of such catalyzers and their industrial application. In view of the specific features of SO2 hydrogenation and organic sulfur hydrolysis during low-temperature hydrogenation, a new technical process involving joint application of hydrogenation catalyzers and hydrolysis catalyzers was proposed. In addition, low-temperature hydrogenation catalyzers and low-temperature hydrolysis catalyzers suitable for low-temperature conditions were developed. Joint application of these two kinds of catalyzers may reduce the inlet temperatures in the conventional hydrogenation reactors from 280 °C to 220 °C, at the same time, hydrogenation conversion rates of SO2 can be enhanced to over 99%. To further accelerate the hydrolysis rate of organic sulfur, the catalyzers for hydrolysis of low-temperature organic sulfur were developed. In lab tests, the volume ratio of the total sulfur content in tail gas can be as low as 131 × 10−6 when these two kinds of catalyzers were used in a proportion of 5:5 in volumes. Industrial application of these catalyzers was implemented in 17 sulfur recovery tail gas processing facilities of 15 companies. As a result, Sinopec Jinling Petrochemical Company had outstanding application performances with a tail gas discharging rate lower than 77.9 mg/m3 and a total sulfur recovery of 99.97%.

  5. Ammonia gas sensors based on In2O3/PANI hetero-nanofibers operating at room temperature

    Directory of Open Access Journals (Sweden)

    Qingxin Nie

    2016-09-01

    Full Text Available Indium nitrate/polyvinyl pyrrolidone (In(NO33/PVP composite nanofibers were synthesized via electrospinning, and then hollow structure indium oxide (In2O3 nanofibers were obtained through calcination with PVP as template material. In situ polymerization was used to prepare indium oxide/polyaniline (In2O3/PANI composite nanofibers with different mass ratios of In2O3 to aniline. The structure and morphology of In(NO33/PVP, In2O3/PANI composite nanofibers and pure PANI were investigated by scanning electron microscopy (SEM, Fourier transform infrared spectroscopy (FTIR, X-ray diffraction (XRD, transmission electron microscopy (TEM and current–voltage (I–V measurements. The gas sensing properties of these materials towards NH3 vapor (100 to 1000 ppm were measured at room temperature. The results revealed that the gas sensing abilities of In2O3/PANI composite nanofibers were better than pure PANI. In addition, the mass ratio of In2O3 to aniline and the p–n heterostructure between In2O3 and PANI influences the sensing performance of the In2O3/PANI composite nanofibers. In this paper, In2O3/PANI composite nanofibers with a mass ratio of 1:2 exhibited the highest response values, excellent selectivity, good repeatability and reversibility.

  6. High temperature gasification and gas cleaning – phase II of the HotVegas project

    OpenAIRE

    Meysel, P.; Halama, S.; Botteghi, F.; Steibel, M.; Nakonz, M.; Rück, R.; Kurowski, P.; Buttler, A.; Spliethoff, H.

    2016-01-01

    The primary objective of the research project HotVeGas is to lay the necessary foundations for the long-term development of future, highly efficient high-temperature gasification processes. This includes integrated hot gas cleaning and optional CO2 capture and storage for next generation IGCC power plants and processes for the development of synthetic fuels. The joint research project is funded by the German Federal Ministry of Economics and Technology and five industry partners. It is coordi...

  7. Hot gas stripping of ammonia and carbon dioxide from simulated and actual in situ retort waters

    Energy Technology Data Exchange (ETDEWEB)

    Murphy, C.L.

    1979-01-01

    This study proved that ammonia and carbon dioxide could be removed from retort water by hot gas stripping and that overall transfer rates were slower than for physical desorption alone. The ammonia in solution complexed with the carbonate species with the result that the CO/sub 2/ transfer rates were linked to the relatively slower desorption of NH/sub 3/ from solution. Ionic reactions in the liquid phase limited the quantity of free NH/sub 3/ and CO/sub 2/, thus decreasing the driving forces for mass transfer. The retort water exhibited foaming tendencies that affected the interfacial area which should be taken into account if a stripping tower is considered on a larger scale. Transfer unit heights were calculated for the process conditions studied and correlated such that scaleup to increased capacities is possible.

  8. Reactor for tracking catalyst nanoparticles in liquid at high temperature under a high-pressure gas phase with X-ray absorption spectroscopy.

    Science.gov (United States)

    Nguyen, Luan; Tao, Franklin Feng

    2018-02-01

    Structure of catalyst nanoparticles dispersed in liquid phase at high temperature under gas phase of reactant(s) at higher pressure (≥5 bars) is important for fundamental understanding of catalytic reactions performed on these catalyst nanoparticles. Most structural characterizations of a catalyst performing catalysis in liquid at high temperature under gas phase at high pressure were performed in an ex situ condition in terms of characterizations before or after catalysis since, from technical point of view, access to the catalyst nanoparticles during catalysis in liquid phase at high temperature under high pressure reactant gas is challenging. Here we designed a reactor which allows us to perform structural characterization using X-ray absorption spectroscopy including X-ray absorption near edge structure spectroscopy and extended X-ray absorption fine structure spectroscopy to study catalyst nanoparticles under harsh catalysis conditions in terms of liquid up to 350 °C under gas phase with a pressure up to 50 bars. This reactor remains nanoparticles of a catalyst homogeneously dispersed in liquid during catalysis and X-ray absorption spectroscopy characterization.

  9. Ambient temperature effects on gas turbine power plant: A case study in Iran

    International Nuclear Information System (INIS)

    Gorji, M.; Fouladi, F.

    2007-01-01

    Actual thermal efficiency, electric-power output, fuel-air ratio and specific fuel consumption (SFC) vary according to the ambient conditions. The amount of these variations greatly affects those parameters as well as the plant incomes. In this paper the effect of ambient temperature as a seasonal variation on a gas power plant has been numerically studied. For this purpose, the gas turbine model and different climate seasonal variations of Ray in Iran are considered in this study. For the model, by using average monthly temperature data of the region, the different effective parameters were compared to those in standard design conditions. The results show that ambient temperature increase will decrease thermal efficiency, electric-power out put and fuel-air ratio of the gas turbine plant whereas increases the specific fuel consumption

  10. Thermal Stress FE Analysis of Large-scale Gas Holder Under Sunshine Temperature Field

    Science.gov (United States)

    Li, Jingyu; Yang, Ranxia; Wang, Hehui

    2018-03-01

    The temperature field and thermal stress of Man type gas holder is simulated by using the theory of sunshine temperature field based on ASHRAE clear-sky model and the finite element method. The distribution of surface temperature and thermal stress of gas holder under the given sunshine condition is obtained. The results show that the thermal stress caused by sunshine can be identified as one of the important factors for the failure of local cracked oil leakage which happens on the sunny side before on the shady side. Therefore, it is of great importance to consider the sunshine thermal load in the stress analysis, design and operation of large-scale steel structures such as the gas holder.

  11. The internal energy and thermodynamic behaviour of a boson gas below the Bose-Einstein temperature

    International Nuclear Information System (INIS)

    Deeney, F.A.; O'Leary, J.P.

    2011-01-01

    We have examined the issue of the kinetic energy of particles in the ground state of an ideal boson gas. By assuming that the particles, on dropping into the ground state, retain the kinetic energy they possess at the Bose-Einstein temperature T B , we obtain new expressions for the pressure and internal energy of the gas below T B , that are free of the difficulties associated with the corresponding expressions in current theory. Furthermore, these new equations yield a value for the maximum density temperature in liquid 4 He that is very close to the measured value. - Highlights: → A new equation of state for an ideal boson gas that is anomaly-free. → A prediction of the existence of a density maximum in all ideal boson gases. → Calculation of the temperature at which a density maximum will occur in liquid 4 He.

  12. High temperature and high pressure gas cell for quantitative spectroscopic measurements

    International Nuclear Information System (INIS)

    Christiansen, Caspar; Stolberg-Rohr, Thomine; Fateev, Alexander; Clausen, Sønnik

    2016-01-01

    A high temperature and high pressure gas cell (HTPGC) has been manufactured for quantitative spectroscopic measurements in the pressure range 1–200 bar and temperature range 300–1300 K. In the present work the cell was employed at up to 100 bar and 1000 K, and measured absorption coefficients of a CO_2–N_2 mixture at 100 bar and 1000 K are revealed for the first time, exceeding the high temperature and pressure combinations previously reported. This paper discusses the design considerations involved in the construction of the cell and presents validation measurements compared against simulated spectra, as well as published experimental data. - Highlights: • A ceramic gas cell designed for gas measurements up to 1300 K and 200 bar. • The first recorded absorption spectrum of CO_2 at 1000 K and 101 bar is presented. • Voigt profiles might suffice in the modeling of radiation from CO_2 in combustion.

  13. Suppression of temperature instability in InGaZnO thin-film transistors by in situ nitrogen doping

    International Nuclear Information System (INIS)

    Raja, Jayapal; Jang, Kyungsoo; Yi, Junsin; Balaji, Nagarajan

    2013-01-01

    We have investigated the effect of nitrogen doping on the behavior of hysteresis curve and its suppression of temperature instability in amorphous InGaZnO thin-film transistors (a-IGZO TFTs). The in situ nitrogen doping reduced the temperature induced abnormal sub threshold leakage current and traps generation. Large falling-rate (F R ) ∼ 0.26 eV V −1 , low activation energy (E a ) ∼ 0.617 eV and a small hysteresis compared to the pure a-IGZO TFTs, shows the best immunity to thermal instability. This is mainly attributed to the reduction of interface trap density and oxygen vacancies due to the passivation of defects and/dangling bonds. (paper)

  14. High-temperature dehydration of talc: a kinetics study using in situ X-ray powder diffraction

    Science.gov (United States)

    Wang, Duojun; Yi, Li; Huang, Bojin; Liu, Chuanjiang

    2015-06-01

    High-temperature in situ X-ray powder diffraction patterns were used to study the dehydration kinetics of natural talc with a size of 10-15 µm. The talc was annealed from 1073 to 1223 K, and the variations in the characteristic peaks corresponding to talc with the time were recorded to determine the reaction progress. The decomposition of talc occurred, and peaks corresponding to talc and peaks corresponding to enstatite and quartz were observed. The enstatite and talc exhibited a topotactic relationship. The dehydration kinetics of talc was studied as a function of temperature between 1073 and 1223 K. The kinetics data could be modeled using an Avrami equation that considers nucleation and growth processes ? where n varies from 0.4 to 0.8. The rate constant (k) equation for the natural talc is ? The reaction mechanism for the dehydration of talc is a heterogeneous nucleation and growth mechanism.

  15. In situ XRD study of C60 polymerisation above pressures of 9 GPa and temperatures up to 830K

    International Nuclear Information System (INIS)

    Talyzin, A.V.; Jansson, U.; Dubrovinsky, L.S.; Oden, M.; Le Bihan, T.

    2002-01-01

    The C60 polymerization was studied by X-ray diffraction in situ in the pressure range 13-18 GPa and at temperatures up to 830 K. The results of the high pressure high temperature treatment are strongly dependent from the history of the sample and stress. At certain conditions no elliptical diffraction patterns were observed at 13 GPa and 830K. Samples with a relatively low internal stress showed a transformation to new phase. It is suggested that this phase is three-dimensional polymer with each C60 molecule bonded to eight neighbors. This phase showed an increased hardness (about 37 GPa) and a Raman spectrum distinctly different from previously known polymeric phases

  16. High temperature metallic materials for gas-cooled reactors

    International Nuclear Information System (INIS)

    1989-06-01

    The Specialists' Meeting was organized in conjunction with an earlier meeting on this topic held in Vienna, Austria, 1981, which provided for a comprehensive review of the status of materials development and testing at that time and for a description of test facilities. This meeting provided an opportunity (1) to review and discuss the progress made since 1981 in the development, testing and qualification of high temperature metallic materials, (2) to critically assess results achieved, and (3) to give directions for future research and development programmes. In particular, the meeting provided a form for a close interaction between component designers and materials specialists. The meeting was attended by 48 participants from France, People's Republic of China, Federal Republic of Germany, Japan, Poland, Switzerland, United Kingdom, USSR and USA presenting 22 papers. The technical part of the meeting was subdivided into four technical sessions: Components Design and Testing - Implications for Materials (4 papers); Microstructure and Environmental Compatibility (4 papers); Mechanical Properties (9 papers); New Alloys and Developments (6 papers). At the end of the meeting a round table discussion was organized in order to summarize the meeting and to make recommendations for future activities. This volume contains all papers presented at the meeting. A separate abstract was prepared for each of these papers. Refs, figs and tabs

  17. In-situ monitoring of etching of bovine serum albumin using low-temperature atmospheric plasma jet

    Science.gov (United States)

    Kousal, J.; Shelemin, A.; Kylián, O.; Slavínská, D.; Biederman, H.

    2017-01-01

    Bio-decontamination of surfaces by means of atmospheric pressure plasma is nowadays extensively studied as it represents promising alternative to commonly used sterilization/decontamination techniques. The non-equilibrium atmospheric pressure plasmas were already reported to be highly effective in removal of a wide range of biological residual from surfaces. Nevertheless the kinetics of removal of biological contamination from surfaces is still not well understood as the majority of performed studies were based on ex-situ evaluation of etching rates, which did not allow investigating details of plasma action on biomolecules. This study therefore presents a real-time, in-situ ellipsometric characterization of removal of bovine serum albumin (BSA) from surfaces by low-temperature atmospheric plasma jet operated in argon. Non-linear and at shorter distances between treated samples and nozzle of the plasma jet also non-monotonic dependence of the removal rate on the treatment duration was observed. According to additional measurements focused on the determination of chemical changes of treated BSA as well as temperature measurements, the observed behavior is most likely connected with two opposing effects: the formation of a thin layer on the top of BSA deposit enriched in inorganic compounds, whose presence causes a gradual decrease of removal efficiency, and slight heating of BSA that facilitates its degradation and volatilization induced by chemically active radicals produced by the plasma.

  18. Design and development of gas turbine high temperature reactor 300 (GTHTR300)

    International Nuclear Information System (INIS)

    Kunitomi, Kazuhiko; Katanishi, Shoji; Takada, Shoji; Takizuka, Takakazu; Yan, Xing; Kosugiyama, Shinichi

    2003-01-01

    JAERI (Japan Atomic Energy Research Institute) started design and development of the high temperature gas cooled reactor with a gas turbine electric generation system, GTHTR300, in April 2001. Design originalities of the GTHTR300 are a horizontally mounted highly efficient gas turbine system and an ultimately simplified safety system such as no containment building and no active emergency core cooling. These design originalities are proposed based on design and operational experiences in conventional gas turbine systems and Japan's first high temperature gas cooled reactor (HTTR: High Temperature Engineering Test Reactor) so that many R and Ds are not required for the development. Except these original design features, devised core design, fuel design and plant design are adopted to meet design requirements and attain a target cost. This paper describes the unique design features focusing on the safety design, reactor core design and gas turbine system design together with a preliminary result of the safety evaluation carried out for a typical severe event. This study is entrusted from Ministry of Education, Culture, Sports, Science and Technology of Japan. (author)

  19. In situ probing of temperature in radio frequency thermal plasma using Yttrium ion emission lines during synthesis of yttria nanoparticles

    Science.gov (United States)

    Dhamale, G. D.; Tiwari, N.; Mathe, V. L.; Bhoraskar, S. V.; Ghorui, S.

    2017-07-01

    Particle feeding is used in the most important applications of radio frequency (r.f.) thermal plasmas like synthesis of nanoparticles and particle spheroidization. The study reports an in-situ investigation of radial distribution of temperature in such devices using yttrium ion emission lines under different rates of particle loading during synthesis of yttria nanoparticles. A number of interesting facts about the response of r.f. plasma to the rate of particle loading, hitherto unknown, are revealed. Observed phenomena are supported with experimental data from fast photographic experiments and actual synthesis results. The use of the Abel inversion technique together with simultaneous multi-track acquisition of emission spectra from different spatial locations using a CCD based spectrometer allowed us to extract accurate distribution of temperature inside the plasma in the presence of inherent instabilities. The temperature profiles of this type of plasma have been measured possibly for the first time while particles are being fed into the plasma. Observed changes in the temperature profiles as the particle feed rate increases are very significant. Reaction forces resulting from particle evaporation, and increased skin depth owing to the decrease in electrical conductivity in the edge region are proposed as the two different mechanisms to account for the observed changes in the temperature profile as the powder feed rate is increased. Quantitative analyses supporting the proposed mechanisms are presented.

  20. Determination of Coherency and Rigidity Temperatures in Al-Cu Alloys Using In Situ Neutron Diffraction During Casting

    Science.gov (United States)

    Drezet, Jean-Marie; Mireux, Bastien; Szaraz, Zoltan; Pirling, Thilo

    2014-08-01

    The rigidity temperature of a solidifying alloy is the temperature at which the solid phase is sufficiently coalesced to transmit tensile stress. It is a major input parameter in numerical modeling of solidification processes as it defines the point at which thermally induced deformations start to generate internal stresses in a casting. This temperature has been determined for an Al-13 wt.% Cu alloy using in situ neutron diffraction during casting in a dog-bone-shaped mold. This setup allows the sample to build up internal stress naturally as its contraction is not possible. The cooling on both sides of the mold induces a hot spot at the middle of the sample that is irradiated by neutrons. Diffraction patterns are recorded every 11 s using a large detector, and the very first change of diffraction angles allows for the determination of the rigidity temperature. We measured rigidity temperatures equal to 557°C and 548°C depending on the cooling rate for grain refined Al-13 wt.% Cu alloys. At a high cooling rate, rigidity is reached during the formation of the eutectic phase. In this case, the solid phase is not sufficiently coalesced to sustain tensile load and thus cannot avoid hot tear formation.

  1. Combination scattering of dissociating gas applied to measurements of temperature and concentration of components

    International Nuclear Information System (INIS)

    Pashkov, V.A.; Kurganova, F.I.; Grishchuk, M.Kh.

    1987-01-01

    The method to calculate the combination scattering power of the components of the dissociating N 2 O 4 ↔ 2NO 2 → 2NO+O 2 gas subjected to the laser radiation effect is given. The combination scattering power has been calculated for temperatures 400-600 K, pressures 1-3 MPa, with the neodymium laser (λ=1.06 μm) as a source and the possibility of measuring the local temperatures and concentration of the given gas components with the help of the combination scattering has been analysed. It follows from the calculated data that combination scattering power of N 2 O 4 ↔ 2NO 2 ↔ 2NO+O 2 gas in excitation with the neodymium laser as a source is sufficient for detection. Gas temperature is likely to be measured with the minimum error relative to stokes and anti-stokes bands of the combination scattering, produced by nitrogen tetroxide. From calculated data it also follows that measurement of NO 2 concentration in the range 400-600 K is possible. At the same time combination scattering power, produced by NO and O 2 components is sufficient for measurement merely with the concentration of the components of the order of 10 18 molecules/cm 3 guaranteed in static conditions only at N 2 O 4 ↔ 2NO 2 ↔ 2NO+O 2 gas temperature 500 K and higher

  2. Monitoring of high temperature area by resistivity tomography during in-situ heating test in sedimentary soft rocks

    International Nuclear Information System (INIS)

    Kubota, Kenji; Suzuki, Koichi; Ikenoya, Takafumi; Takakura, Nozomu; Tani, Kazuo

    2009-01-01

    One of the major issues in disposal of nuclear waste is that the long term behaviors of sedimentary soft rocks can be affected by various environmental factors such as temperature, mechanical conditions or hydraulic conditions. Therefore, it is necessary to develop a method for evaluating the long term stability of caverns in sedimentary soft rocks as subjected to changes of environment. We have conducted in-situ heating test to evaluate the influence of high temperature to the surrounding rock mass at a depth of 50 m. The well with a diameter of 30 cm and 60 cm of height, was drilled and filled with groundwater. The heater was installed in the well for heating the surrounding rock mass. During the heating, temperature and deformation around the well were measured. To evaluate the influence of heating on sedimentary soft rocks, it is important to monitor the extent of heated area. Resistivity monitoring is thought to be effective to map the extent of the high temperature area. So we have conducted resistivity tomography during the heating test. The results demonstrated that the resistivity of the rock mass around the heating well decreased and this area was gradually expanded from the heated area during the heating. The decreasing rate of resistivity on temperature is correlated to that of laboratory experimental result and existing empirical formula between aqueous solution resistivity and temperature. Resistivity is changed by many other factors, but it is expected that resistivity change by other factors is very few in this test. This suggests that high temperature area is detected and spatial distribution of temperature can be mapped by resistivity tomography. So resistivity tomography is expected to be one of the promising methods to monitor the area heated by nuclear waste. (author)

  3. Inspired gas humidity and temperature during mechanical ventilation with the Stephanie ventilator.

    Science.gov (United States)

    Preo, Bianca L; Shadbolt, Bruce; Todd, David A

    2013-11-01

    To measure inspired gas humidity and temperature delivered by a Stephanie neonatal ventilator with variations in (i) circuit length; (ii) circuit insulation; (iii) proximal airway temperature probe (pATP) position; (iv) inspiratory temperature (offset); and (v) incubator temperatures. Using the Stephanie neonatal ventilator, inspired gas humidity and temperature were measured during mechanical ventilation at the distal inspiratory limb and 3 cm down the endotracheal tube. Measurements were made with a long or short circuit; with or without insulation of the inspiratory limb; proximal ATP (pATP) either within or external to the incubator; at two different inspiratory temperature (offset) of 37(-0.5) and 39(-2.0)°C; and at three different incubator temperatures of 32, 34.5, and 37°C. Long circuits produced significantly higher inspired humidity than short circuits at all incubator settings, while only at 32°C was the inspired temperature higher. In the long circuits, insulation further improved the inspired humidity especially at 39(-2.0)°C, while only at incubator temperatures of 32 and 37°C did insulation significantly improve inspired temperature. Positioning the pATP outside the incubator did not result in higher inspired humidity but did significantly improve inspired temperature. An inspiratory temperature (offset) of 39(-2.0)°C delivered significantly higher inspired humidity and temperature than the 37(-0.5)°C especially when insulated. Long insulated Stephanie circuits should be used for neonatal ventilation when the infant is nursed in an incubator. The recommended inspiratory temperature (offset) of 37(-0.5)°C produced inspired humidity and temperature below international standards, and we suggest an increase to 39(-2.0)°C. © 2013 John Wiley & Sons Ltd.

  4. Growth and decay of a two-dimensional oxide quasicrystal: High-temperature in situ microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Foerster, Stefan [Physik-Institut, Universitaet Zuerich (Switzerland); Institute of Physics, Martin-Luther-Universitaet Halle-Wittenberg, Halle (Germany); Flege, Jan Ingo; Falta, Jens [Institute of Solid State Physics, University of Bremen (Germany); MAPEX Center for Materials and Processes, University of Bremen (Germany); Zollner, Eva Maria; Schumann, Florian Otto; Hammer, Rene; Bayat, Alireza; Schindler, Karl-Michael [Institute of Physics, Martin-Luther-Universitaet Halle-Wittenberg, Halle (Germany); Widdra, Wolf [Institute of Physics, Martin-Luther-Universitaet Halle-Wittenberg, Halle (Germany); Max-Planck-Institut fuer Mikrostrukturphysik, Halle (Germany)

    2017-01-15

    The recently discovered two-dimensional oxide quasicrystal (OQC) derived from BaTiO{sub 3} on Pt(111) is the first material in which a spontaneous formation of an aperiodic structure at the interface to a periodic support has been observed. Herein, we report in situ low-energy electron microscopy (LEEM) studies on the fundamental processes involved in the OQC growth. The OQC formation proceeds in two steps via of an amorphous two-dimensional wetting layer. At 1170 K the long-range aperiodic order of the OQC develops. Annealing in O{sub 2} induces the reverse process, the conversion of the OQC into BaTiO{sub 3} islands and bare Pt(111), which has been monitored by in situ LEEM. A quantitative analysis of the temporal decay of the OQC shows that oxygen adsorption on bare Pt patches is the rate limiting step of this dewetting process. (copyright 2016 by WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

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

    Directory of Open Access Journals (Sweden)

    Guangwen Fan

    2015-09-01

    Full Text Available 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.

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

    Science.gov (United States)

    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.

  7. Refinements to temperature calculations of spent fuel assemblies when in a stagnant gas environment

    International Nuclear Information System (INIS)

    Rhodes, C.A.; Haire, M.J.

    1984-01-01

    Undesirably high temperatures are possible in irradiated fuel assemblies because of the radioactive decay of fission products formed while in the reactor. The COXPRO computer code has been used for some time to calculate temperatures in spent fuel when the fuel is suspended in a stagnant gas environment. This code assumed radiation to be the only mode of heat dissipation within the fuel pin bundle. Refinements have been made to include conduction as well as radiation heat transfer within this code. Comparison of calculated and measured temperatures in four separate and independent tests indicate that maximum fuel assembly temperatures can be predicted to within about 6%. 2 references, 5 figures

  8. Comparison between remotely-sensed sea-surface temperature (AVHRR and in situ records in San Matías Gulf (Patagonia, Argentina

    Directory of Open Access Journals (Sweden)

    Gabriela N Williams

    2014-03-01

    Full Text Available In situ records of sea surface temperature collected between 2005 and 2009 were used to compare, for the first time, the temperature estimated by the Multichannel algorithms (MCSST of the Advanced Very High Resolution Radiometer (AVHRR sensors in San Matías Gulf, in the north of the Argentinean Patagonian Continental Shelf (between 40°47'-42°13'S. Match-ups between in situ records and satellite sea surface temperature (SST were analyzed. In situ records came from fixed stations and oceanographic cruises, while satellite data came from different NOAA satellites. The fitting of temperature data to a Standard Major Axis (SMA type II regression model indicated that a high proportion of the total variance (0.53< r² <0.99 was explained by this model showing a high correlation between in situ data and satellite estimations. The mean differences between satellite and in situ data for the full data set were 1.64 ± 1.49°C. Looking separately into in situ data from different sources and day and night estimates from different NOAA satellites, the differences were between 0.30 ± 0.60°C and 2.60 ± 1.50°C. In this paper we discuss possible reasons for the above-mentioned performance of the MCSST algorithms in the study area.

  9. The finite-temperature thermodynamics of a trapped unitary Fermi gas within fractional exclusion statistics

    International Nuclear Information System (INIS)

    Qin Fang; Chen Jisheng

    2010-01-01

    We utilize the fractional exclusion statistics of the Haldane and Wu hypothesis to study the thermodynamics of a unitary Fermi gas trapped in a harmonic oscillator potential at ultra-low finite temperature. The entropy per particle as a function of the energy per particle and energy per particle versus rescaled temperature are numerically compared with the experimental data. The study shows that, except the chemical potential behaviour, there exists a reasonable consistency between the experimental measurement and theoretical attempt for the entropy and energy per particle. In the fractional exclusion statistics formalism, the behaviour of the isochore heat capacity for a trapped unitary Fermi gas is also analysed.

  10. Transport properties of natural gas through polyethylene nanocomposites at high temperature and pressure

    DEFF Research Database (Denmark)

    Adewole, Jimoh K.; Jensen, Lars; Al-Mubaiyedh, Usamah A.

    2012-01-01

    High density polyethylene (HDPE)/clay nanocomposites containing nanoclay concentrations of 1, 2.5, and 5 wt% were prepared by a melt blending process. The effects of various types of nanoclays and their concentrations on permeability, solubility, and diffusivity of natural gas in the nanocomposites...... at constant temperature had little influence on the permeability, whereas increasing the temperature from 30 to 70 degrees C significantly increased the permeability of the gas. Additionally, the effect of crystallinity on permeability, solubility, and diffusivity was investigated. Thus, the permeability...

  11. Simulation of the fuzzy-smith control system for the high temperature gas cooled reactor

    International Nuclear Information System (INIS)

    Li Deheng; Xu Xiaolin; Zheng Jie; Guo Renjun; Zhang Guifen

    1997-01-01

    The Fuzzy-Smith pre-estimate controller to solve the control of the big delay system is developed, accompanied with the development of the mathematical model of the 10 MW high temperature gas cooled test reactor (HTR-10) and the design of its control system. The simulation results show the Fuzzy-Smith pre-estimate controller has the advantages of both fuzzy control and Smith pre-estimate controller; it has better compensation to the delay and better adaptability to the parameter change of the control object. So it is applicable to the design of the control system for the high temperature gas cooled reactor

  12. Experimental studies on particle deposition by thermophoresis and inertial impaction from particulate high temperature gas flow

    International Nuclear Information System (INIS)

    Kim, S.S.; Kim, Y.J.

    1987-01-01

    In view of fouling and erosion of gas turbine blade, heat exchanger and pipelines, increasing attention has been paid to particle deposition (transport) in high temperature flow systems. This is also necessary to develop a cleaning or filtration devices. Using 'real time' laser-light reflectivity and scanning electron microscope technique, we quantitatively treat particle size effect and the interaction between Brownian diffusion, thermoporesis (particle drift down a temperature gradient), and inertial impaction of particles (0.2 to 30 μm in diameter) in laminar hot combustion gas-particles flow (ca. 1565 K)

  13. Sensor Fabrication Method for in Situ Temperature and Humidity Monitoring of Light Emitting Diodes

    Directory of Open Access Journals (Sweden)

    Chi-Yuan Lee

    2010-04-01

    Full Text Available In this work micro temperature and humidity sensors are fabricated to measure the junction temperature and humidity of light emitting diodes (LED. The junction temperature is frequently measured using thermal resistance measurement technology. The weakness of this method is that the timing of data capture is not regulated by any standard. This investigation develops a device that can stably and continually measure temperature and humidity. The device is light-weight and can monitor junction temperature and humidity in real time. Using micro-electro-mechanical systems (MEMS, this study minimizes the size of the micro temperature and humidity sensors, which are constructed on a stainless steel foil substrate (40 μm-thick SS-304. The micro temperature and humidity sensors can be fixed between the LED chip and frame. The sensitivities of the micro temperature and humidity sensors are 0.06 ± 0.005 (Ω/°C and 0.033 pF/%RH, respectively.

  14. Facility Configuration Study of the High Temperature Gas-Cooled Reactor Component Test Facility

    Energy Technology Data Exchange (ETDEWEB)

    S. L. Austad; L. E. Guillen; D. S. Ferguson; B. L. Blakely; D. M. Pace; D. Lopez; J. D. Zolynski; B. L. Cowley; V. J. Balls; E.A. Harvego, P.E.; C.W. McKnight, P.E.; R.S. Stewart; B.D. Christensen

    2008-04-01

    A test facility, referred to as the High Temperature Gas-Cooled Reactor Component Test Facility or CTF, will be sited at Idaho National Laboratory for the purposes of supporting development of high temperature gas thermal-hydraulic technologies (helium, helium-Nitrogen, CO2, etc.) as applied in heat transport and heat transfer applications in High Temperature Gas-Cooled Reactors. Such applications include, but are not limited to: primary coolant; secondary coolant; intermediate, secondary, and tertiary heat transfer; and demonstration of processes requiring high temperatures such as hydrogen production. The facility will initially support completion of the Next Generation Nuclear Plant. It will secondarily be open for use by the full range of suppliers, end-users, facilitators, government laboratories, and others in the domestic and international community supporting the development and application of High Temperature Gas-Cooled Reactor technology. This pre-conceptual facility configuration study, which forms the basis for a cost estimate to support CTF scoping and planning, accomplishes the following objectives: • Identifies pre-conceptual design requirements • Develops test loop equipment schematics and layout • Identifies space allocations for each of the facility functions, as required • Develops a pre-conceptual site layout including transportation, parking and support structures, and railway systems • Identifies pre-conceptual utility and support system needs • Establishes pre-conceptual electrical one-line drawings and schedule for development of power needs.

  15. Facility Configuration Study of the High Temperature Gas-Cooled Reactor Component Test Facility

    International Nuclear Information System (INIS)

    S. L. Austad; L. E. Guillen; D. S. Ferguson; B. L. Blakely; D. M. Pace; D. Lopez; J. D. Zolynski; B. L. Cowley; V. J. Balls; E.A. Harvego, P.E.; C.W. McKnight, P.E.; R.S. Stewart; B.D. Christensen

    2008-01-01

    A test facility, referred to as the High Temperature Gas-Cooled Reactor Component Test Facility or CTF, will be sited at Idaho National Laboratory for the purposes of supporting development of high temperature gas thermal-hydraulic technologies (helium, helium-Nitrogen, CO2, etc.) as applied in heat transport and heat transfer applications in High Temperature Gas-Cooled Reactors. Such applications include, but are not limited to: primary coolant; secondary coolant; intermediate, secondary, and tertiary heat transfer; and demonstration of processes requiring high temperatures such as hydrogen production. The facility will initially support completion of the Next Generation Nuclear Plant. It will secondarily be open for use by the full range of suppliers, end-users, facilitators, government laboratories, and others in the domestic and international community supporting the development and application of High Temperature Gas-Cooled Reactor technology. This pre-conceptual facility configuration study, which forms the basis for a cost estimate to support CTF scoping and planning, accomplishes the following objectives: (1) Identifies pre-conceptual design requirements; (2) Develops test loop equipment schematics and layout; (3) Identifies space allocations for each of the facility functions, as required; (4) Develops a pre-conceptual site layout including transportation, parking and support structures, and railway systems; (5) Identifies pre-conceptual utility and support system needs; and (6) Establishes pre-conceptual electrical one-line drawings and schedule for development of power needs

  16. Effect of temperature on the permeability of gas adsorbed coal under triaxial stress conditions

    Science.gov (United States)

    Li, Xiangchen; Yan, Xiaopeng; Kang, Yili

    2018-04-01

    The combined effects of gas sorption, stress and temperature play a significant role in the changing behavior of gas permeability in coal seams. The effect of temperature on nitrogen and methane permeability of naturally fractured coal is investigated. Coal permeability, P-wave velocity and axial strain were simultaneously measured under two effective stresses and six different temperatures. The results showed that the behavior of nitrogen and methane permeability presented nonmonotonic changes with increasing temperature. The variation in the P-wave velocity and axial strain showed a good correspondence with coal permeability. A higher effective stress limited the bigger deformation and caused the small change in permeability. Methane adsorption and desorption significantly influence the mechanical properties of coal and play an important role in the variations in coal permeability. The result of coal permeability during a complete stress-strain process showed that the variation in permeability is determined by the evolution of the internal structure. The increase in the temperature of the gas saturated coal causes the complex interaction between matrix swelling, matrix shrinkage and micro-fracture generation, which leads to the complex changes in coal structure and permeability. These results are helpful to understand the gas transport mechanism for exploiting coal methane by heat injection.

  17. Processing and structure of in situ Fe-Al alloys produced by gas tungsten arc welding

    Energy Technology Data Exchange (ETDEWEB)

    Banovic, S.W.; DuPont, J.N.; Marder, A.R. [Lehigh Univ., Bethlehem, PA (United States). Energy Research Center

    1997-02-14

    Iron aluminide weld overlays are being investigated for corrosion and erosion protection of boiler tubes in low NOx burners. The primary objective of the research is to identify overlay compositions which can be deposited in a crack-free condition and provide corrosion protection in moderately reducing environments. In the current phase of work, Fe-Al alloy weld overlays were produced by depositing commercially pure aluminum wire on to low carbon steel substrates using Gas Tungsten Arc Welding. A systematic variation of the wire feed speed and current, two major factors affecting dilution, resulted in a variation in aluminum contents of the welds ranging from 3--42 wt% aluminum. The aluminum content was observed to increase with wire feed speed and a decrease in the current. The aluminum content was also found to affect the cracking susceptibility of the overlays. At 10wt% aluminum, few to no cracks were observed in the deposits. Above this value, cracking was prevalent throughout the weld. In addition, two types of microstructures were found correlating to different concentrations of aluminum. A homogeneous matrix with second phase particles consisting of coarse columnar grains was found for low aluminum concentrations. With higher aluminum contents, a two-phase constituent was observed to surround primary dendrites growing from the substrate. The transition of the microstructures occurred between 24 and 32 wt% Al.

  18. Design study on evaluation for power conversion system concepts in high temperature gas cooled reactor with gas turbine

    International Nuclear Information System (INIS)

    Minatsuki, Isao; Mizokami, Yorikata

    2007-01-01

    The design studies on High Temperature Gas Cooled Reactor with Gas Turbine (HTGR-GT) have been performed, which were mainly promoted by Japan Atomic Energy Agency (JAEA) and supported by fabricators in Japan. HTGR-GT plant feature is almost determined by selection of power conversion system concepts. Therefore, plant design philosophy is observed characteristically in selection of them. This paper describes the evaluation and analysis of the essential concepts of the HTGR-GT power conversion system through the investigations based on our experiences and engineering knowledge as a fabricator. As a result, the following concepts were evaluated that have advantages against other competitive one, such as the horizontal turbo machine rotor, the turbo machine in an individual vessel, the turbo machine with single shaft, the generator inside the power conversion vessel, and the power conversion system cycle with an intercooler. The results of the study can contribute as reference data when the concepts will be selected. Furthermore, we addressed reasonableness about the concept selection of the Gas Turbine High Temperature Reactor GTHTR300 power conversion system, which has been promoted by JAEA. As a conclusion, we recognized the GTHTR300 would be one of the most promising concepts for commercialization in near future. (author)

  19. In situ observation · analytical technologies of high temperature superconductor for fusion reactor at ultra low temperature

    International Nuclear Information System (INIS)

    Kimoto, Takayoshi; Sun, Wei; Fukutomi, Katsuo; Togano, Kazumasa; Saito, Tetsuya; Hiraga, Kenji; Takeda, Toshiyuki

    1998-01-01

    An image installation program of SPARK station 20 was accomplished. It can induce continuously 2.1 MB TEM image at 5 sheet/sec until 160 sheets. An image processing (shift addition) program was developed at first in the world. The program can overlap many sheet of TEM images by shifting them to the correct position. Other image processing programs such as flatfielding and reducing noise processing were developed. High temperature lattice fringe image of superconductive oxide Bi2223 in the drift chamber can be observed at low temperature by using the above image processing programs. New type laser device for filament radiation which consists of argon ion laser was developed as the first step of development of high brightness electron gun. Bi2212 single crystal was determined by the large angle convergent beam electron diffraction. The results showed the crystal structure belonged to Bbmb. (S.Y.)

  20. Temperature-induced transition of the diffusion mechanism of n-hexane in ultra-thin polystyrene films, resolved by in-situ Spectroscopic Ellipsometry

    NARCIS (Netherlands)

    Ogieglo, Wojciech; Wormeester, Herbert; Wessling, Matthias; Benes, Nieck Edwin

    2013-01-01

    In-situ Spectroscopic Ellipsometry is used to study diffusion of liquid n-hexane in silicon wafer supported 150 nm thick polystyrene films, in the temperature range 16e28 C. In the higher part of this temperature range Case II diffusion is shown to be dominant. In this case the temporal evolution of

  1. High-Temperature Corrosion Behavior of Alloy 617 in Helium Environment of Very High Temperature Gas Reactor

    International Nuclear Information System (INIS)

    Lee, Gyeong-Geun; Jung, Sujin; Kim, Daejong; Jeong, Yong-Whan; Kim, Dong-Jin

    2012-01-01

    Alloy 617 is a Ni-base superalloy and a candidate material for the intermediate heat exchanger (IHX) of a very high temperature gas reactor (VHTR) which is one of the next generation nuclear reactors under development. The high operating temperature of VHTR enables various applications such as mass production of hydrogen with high energy efficiency. Alloy 617 has good creep resistance and phase stability at high temperatures in an air environment. However, it was reported that the mechanical properties decreased at a high temperature in an impure helium environment. In this study, high-temperature corrosion tests were carried out at 850°C-950°C in a helium environment containing the impurity gases H_2, CO, and CH_4, in order to examine the corrosion behavior of Alloy 617. Until 250 h, Alloy 617 specimens showed a parabolic oxidation behavior at all temperatures. The activation energy for oxidation in helium environment was 154 kJ/mol. The SEM and EDS results elucidated a Cr-rich surface oxide layer, Al-rich internal oxides and depletion of grain boundary carbides. The thickness and depths of degraded layers also showed a parabolic relationship with time. A normal grain growth was observed in the Cr-rich surface oxide layer. When corrosion tests were conducted in a pure helium environment, the oxidation was suppressed drastically. It was elucidated that minor impurity gases in the helium would have detrimental effects on the high temperature corrosion behavior of Alloy 617 for the VHTR application.

  2. Effects of Loading Rate on Gas Seepage and Temperature in Coal and Its Potential for Coal-Gas Disaster Early-Warning

    Directory of Open Access Journals (Sweden)

    Chong Zhang

    2017-08-01

    Full Text Available The seepage velocity and temperature externally manifest the changing structure, gas desorption and energy release that occurs in coal containing gas failure under loading. By using the system of coal containing gas failure under loading, this paper studies the law of seepage velocity and temperature under different loading rates and at 1.0 MPa confining pressure and 0.5 MPa gas pressure, and combined the on-site results of gas pressure and temperature. The results show that the stress directly affects the seepage velocity and temperature of coal containing gas, and the pressure and content of gas have the most sensitivity to mining stress. Although the temperature is not sensitive to mining stress, it has great correlation with mining stress. Seepage velocity has the characteristic of critically slowing down under loading. This is demonstrated by the variance increasing before the main failure of the samples. Therefore, the variance of seepage velocity with time and temperature can provide an early warning for coal containing gas failing and gas disasters in a coal mine.

  3. Numerical investigation of heat transfer in high-temperature gas-cooled reactors

    Energy Technology Data Exchange (ETDEWEB)

    Chen, g.; Anghaie, S. [Univ. of Florida, Gainesville, FL (United States)

    1995-09-01

    This paper proposes a computational model for analysis of flow and heat transfer in high-temperature gas-cooled reactors. The formulation of the problem is based on using the axisymmetric, thin layer Navier-Stokes equations. A hybrid implicit-explicit method based on finite volume approach is used to numerically solve the governing equations. A fast converging scheme is developed to accelerate the Gauss-Siedel iterative method for problems involving the wall heat flux boundary condition. Several cases are simulated and results of temperature and pressure distribution in the core are presented. Results of a parametric analysis for the assessment of the impact of power density on the convective heat transfer rate and wall temperature are discussed. A comparative analysis is conducted to identify the Nusselt number correlation that best fits the physical conditions of the high-temperature gas-cooled reactors.

  4. Long-term, high frequency in situ measurements of intertidal mussel bed temperatures using biomimetic sensors

    Science.gov (United States)

    Helmuth, Brian; Choi, Francis; Matzelle, Allison; Torossian, Jessica L.; Morello, Scott L.; Mislan, K.A.S.; Yamane, Lauren; Strickland, Denise; Szathmary, P. Lauren; Gilman, Sarah E.; Tockstein, Alyson; Hilbish, Thomas J.; Burrows, Michael T.; Power, Anne Marie; Gosling, Elizabeth; Mieszkowska, Nova; Harley, Christopher D.G.; Nishizaki, Michael; Carrington, Emily; Menge, Bruce; Petes, Laura; Foley, Melissa M.; Johnson, Angela; Poole, Megan; Noble, Mae M.; Richmond, Erin L.; Robart, Matt; Robinson, Jonathan; Sapp, Jerod; Sones, Jackie; Broitman, Bernardo R.; Denny, Mark W.; Mach, Katharine J.; Miller, Luke P.; O’Donnell, Michael; Ross, Philip; Hofmann, Gretchen E.; Zippay, Mackenzie; Blanchette, Carol; Macfarlan, J.A.; Carpizo-Ituarte, Eugenio; Ruttenberg, Benjamin; Peña Mejía, Carlos E.; McQuaid, Christopher D.; Lathlean, Justin; Monaco, Cristián J.; Nicastro, Katy R.; Zardi, Gerardo

    2016-01-01

    At a proximal level, the physiological impacts of global climate change on ectothermic organisms are manifest as changes in body temperatures. Especially for plants and animals exposed to direct solar radiation, body temperatures can be substantially different from air temperatures. We deployed biomimetic sensors that approximate the thermal characteristics of intertidal mussels at 71 sites worldwide, from 1998-present. Loggers recorded temperatures at 10–30 min intervals nearly continuously at multiple intertidal elevations. Comparisons against direct measurements of mussel tissue temperature indicated errors of ~2.0–2.5 °C, during daily fluctuations that often exceeded 15°–20 °C. Geographic patterns in thermal stress based on biomimetic logger measurements were generally far more complex than anticipated based only on ‘habitat-level’ measurements of air or sea surface temperature. This unique data set provides an opportunity to link physiological measurements with spatially- and temporally-explicit field observations of body temperature. PMID:27727238

  5. Fundamental conceptual design of the experimental multi-purpose high-temperature gas-cooled reactor

    International Nuclear Information System (INIS)

    Shimokawa, Junichi; Yasuno, Takehiko; Yasukawa, Shigeru; Mitake, Susumu; Miyamoto, Yoshiaki

    1975-06-01

    The fundamental conceptual design of the experimental multi-purpose very high-temperature gas-cooled reactor (experimental VHTR of thermal output 50 MW with reactor outlet-gas temperature 1,000 0 C) has been carried out to provide the operation modes of the system consisting of the reactor and the heat-utilization system, including characteristics and performance of the components and safety of the plant system. For the heat-utilization system of the plant, heat distribution, temperature condition, cooling system constitution, and the containment facility are specified. For the operation of plant, testing capability of the reactor and controlability of the system are taken into consideration. Detail design is made of the fuel element, reactor core, reactivity control and pressure vessel, and also the heat exchanger, steam reformer, steam generator, helium circulator, helium-gas turbine, and helium-gas purification, fuel handling, and engineered safety systems. Emphasis is placed on providing the increase of the reactor outlet-gas temperature. Fuel element design is directed to the prismatic graphite blocks of hexagonal cross-section accommodating the hollow or tubular fuel pins sheathed in graphite sleeve. The reactor core is composed of 73 fuel columns in 7 stages, concerning the reference design MK-II. Orificing is made in the upper portion of core; one orifice for every 7 fuel columns. Average core power density is 2.5 watts/cm 3 . Fuel temperature is kept below 1,300 0 C in rated power. The main components, i.e. pressure vessel, reformer, gas turbine and intermediate heat exchanger are designed in detail; the IHX is of a double-shell and helically-wound tube coils, the reformer is of a byonet tube type, and the turbine-compressor unit is of an axial flow type (turbine in 6 stages and compressor in 16 stages). (auth.)

  6. In-Situ Acoustic Measurements of Temperature Profile in Extreme Environments

    Energy Technology Data Exchange (ETDEWEB)

    Skliar, Mikhail [Univ. of Utah, Salt Lake City, UT (United States)

    2015-03-31

    A gasifier’s temperature is the primary characteristic that must be monitored to ensure its performance and the longevity of its refractory. One of the key technological challenges impacting the reliability and economics of coal and biomass gasification is the lack of temperature sensors that are capable of providing accurate, reliable, and long-life performance in an extreme gasification environment. This research has proposed, demonstrated, and validated a novel approach that uses a noninvasive ultrasound method that provides real-time temperature distribution monitoring across the refractory, especially the hot face temperature of the refractory. The essential idea of the ultrasound measurements of segmental temperature distribution is to use an ultrasound propagation waveguide across a refractory that has been engineered to contain multiple internal partial reflectors at known locations. When an ultrasound excitation pulse is introduced on the cold side of the refractory, it will be partially reflected from each scatterer in the US propagation path in the refractory wall and returned to the receiver as a train of partial echoes. The temperature in the corresponding segment can be determined based on recorded ultrasonic waveform and experimentally defined relationship between the speed of sound and temperature. The ultrasound measurement method offers a powerful solution to provide continuous real time temperature monitoring for the occasions that conventional thermal, optical and other sensors are infeasible, such as the impossibility of insertion of temperature sensor, harsh environment, unavailable optical path, and more. Our developed ultrasound system consists of an ultrasound engineered waveguide, ultrasound transducer/receiver, and data acquisition, logging, interpretation, and online display system, which is simple to install on the existing units with minimal modification on the gasifier or use with new units. This system has been successfully tested

  7. Low-temperature thermometry. Use of a gas thermometer as a calibration standard between 4 and 300 K

    International Nuclear Information System (INIS)

    Combarieu, A. de

    1978-01-01

    A constant volume gas thermometer was built to calibrate the various secondary thermometers used at low temperature. This gas thermometer is placed in a cryostat where any stable temperature between 4 and 300 K may be obtained. After some words about low temperature thermometry, the gas thermometer and its auxiliary equipment are described briefly; the corrections to be applied to the results are given and the article ends with a table showing the values obtained [fr

  8. Mathematical Simulation of Convective Heat Transfer in the Low-Temperature Storage of Liquefied Natural Gas

    OpenAIRE

    Shestakov, Igor; Dolgova, Anastasia; Maksimov, Vyacheslav Ivanovich

    2015-01-01

    The article shows the results of mathematical modeling of convective heat transfer in the low-temperature storage of liquefied natural gas. Regime of natural convection in an enclosure with different intensity of the heat flux at the external borders are investigated. Was examined two-dimensional nonstationary problem within the model of Navier-Stokes in dimensionless variables “vorticity - stream function - temperature”. Distributions of hydrodynamic parameters and temperatures that characte...

  9. High Temperature Gas-Cooled Reactors Lessons Learned Applicable to the Next Generation Nuclear Plant

    International Nuclear Information System (INIS)

    Beck, J.M.; Collins, J.W.; Garcia, C.B.; Pincock, L.F.

    2010-01-01

    High Temperature Gas Reactors (HTGR) have been designed and operated throughout the world over the past five decades. These seven HTGRs are varied in size, outlet temperature, primary fluid, and purpose. However, there is much the Next Generation Nuclear Plant (NGNP) has learned and can learn from these experiences. This report captures these various experiences and documents the lessons learned according to the physical NGNP hardware (i.e., systems, subsystems, and components) affected thereby.

  10. Investigation into relative temperature measurement of pulsed constrained gas flow using passive acoustic means

    OpenAIRE

    Moss, Joseph Brian

    2011-01-01

    peer-reviewed The requirement to measure the real time, dynamic temperature of exhaust system gases is becoming more and more important in the areas of aeronautics, automotive (cars, trucks, etc), marine and industrial/environmental applications, in particular on a cycleby-cycle (CBC) basis. Monitoring exhaust gas temperatures of any power-plant can give important diagnostic information for the monitoring of fuel mixture, combustion efficiency etc. This 'diagnostic' information can b...

  11. An in situ Raman spectroscopy system for long-term corrosion experiments in high temperature water up to 673 K

    International Nuclear Information System (INIS)

    Domae, Masafumi; Tani, Jun-ichi; Fujiwara, Kazutoshi; Katsumura, Yosuke

    2006-01-01

    A Raman spectroscopy system has been developed, in order to identify oxides formed on the surfaces of metals and steels in high temperature water up to 673 K. A supercritical water loop system including a Raman cell was installed. The design of the loop system is up to 673 K and 40 MPa. The Raman cell has a diamond window without window-to-metal packing. Raman spectrum of alumina plate was measured at room temperature, at 523 and at 673 K under pressure of 25 MPa. A long-term measurement was also performed at 523 K and 25 MPa for 117.5 h. In all cases intense Raman peaks attributed to alumina were observed. Raman spectrum of anatase particles in suspension was measured at 673 K and 25 MPa. The results show that the Raman spectroscopy system developed in the present study works well not only for plate sample but also for suspension. Raman spectra observed for titanium plate in high temperature water of 673 K and 25 MPa show growth of several Raman peaks with time up to 257 h. The peaks disappeared after cooled down to room temperature. The experimental results have demonstrated importance of in situ Raman spectroscopy. (author)

  12. Influence of Sintering Temperature on the Microstructure and Mechanical Properties of In Situ Reinforced Titanium Composites by Inductive Hot Pressing

    Directory of Open Access Journals (Sweden)

    Cristina Arévalo

    2016-11-01

    Full Text Available This research is focused on the influence of processing temperature on titanium matrix composites reinforced through Ti, Al, and B4C reactions. In order to investigate the effect of Ti-Al based intermetallic compounds on the properties of the composites, aluminum powder was incorporated into the starting materials. In this way, in situ TixAly were expected to form as well as TiB and TiC. The specimens were fabricated by the powder metallurgy technique known as inductive hot pressing (iHP, using a temperature range between 900 °C and 1400 °C, at 40 MPa for 5 min. Raising the inductive hot pressing temperature may affect the microstructure and properties of the composites. Consequently, the variations of the reinforcing phases were investigated. X-ray diffraction, microstructural analysis, and mechanical properties (Young’s modulus and hardness of the specimens were carried out to evaluate and determine the significant influence of the processing temperature on the behavior of the composites.

  13. Nanocalorimeter platform for in situ specific heat measurements and x-ray diffraction at low temperature

    Energy Technology Data Exchange (ETDEWEB)

    Willa, K. [Materials Science Division, Argonne National Laboratory, 9700 South Cass Avenue, Argonne, Illinois 60439, USA; Diao, Z. [Department of Physics, Stockholm University, SE-106 91 Stockholm, Sweden; Laboratory of Mathematics, Physics and Electrical Engineering, Halmstad University, P.O. Box 823, SE-301 18 Halmstad, Sweden; Campanini, D. [Department of Physics, Stockholm University, SE-106 91 Stockholm, Sweden; Welp, U. [Materials Science Division, Argonne National Laboratory, 9700 South Cass Avenue, Argonne, Illinois 60439, USA; Divan, R. [Center for Nanoscale Materials, Argonne National Laboratory, 9700 South Cass Avenue, Argonne, Illinois 60439, USA; Hudl, M. [Department of Physics, Stockholm University, SE-106 91 Stockholm, Sweden; Islam, Z. [X-ray Science Division, Argonne National Laboratory, 9700 South Cass Avenue, Argonne, Illinois 60439, USA; Kwok, W. -K. [Materials Science Division, Argonne National Laboratory, 9700 South Cass Avenue, Argonne, Illinois 60439, USA; Rydh, A. [Department of Physics, Stockholm University, SE-106 91 Stockholm, Sweden

    2017-12-01

    Recent advances in electronics and nanofabrication have enabled membrane-based nanocalorimetry for measurements of the specific heat of microgram-sized samples. We have integrated a nanocalorimeter platform into a 4.5 T split-pair vertical-field magnet to allow for the simultaneous measurement of the specific heat and x-ray scattering in magnetic fields and at temperatures as low as 4 K. This multi-modal approach empowers researchers to directly correlate scattering experiments with insights from thermodynamic properties including structural, electronic, orbital, and magnetic phase transitions. The use of a nanocalorimeter sample platform enables numerous technical advantages: precise measurement and control of the sample temperature, quantification of beam heating effects, fast and precise positioning of the sample in the x-ray beam, and fast acquisition of x-ray scans over a wide temperature range without the need for time-consuming re-centering and re-alignment. Furthermore, on an YBa2Cu3O7-delta crystal and a copper foil, we demonstrate a novel approach to x-ray absorption spectroscopy by monitoring the change in sample temperature as a function of incident photon energy. Finally, we illustrate the new insights that can be gained from in situ structural and thermodynamic measurements by investigating the superheated state occurring at the first-order magneto-elastic phase transition of Fe2P, a material that is of interest for magnetocaloric applications.

  14. Novel Quantification of Sediment Concentration in Turbidity Currents Through in-situ Measurements of Conductivity and Temperature

    Science.gov (United States)

    Xu, J.; Wang, Z.; Gwiazda, R.; Paull, C. K.; Talling, P.; Parsons, D. R.; Maier, K. L.; Simmons, S.; Cartigny, M.

    2017-12-01

    During a large turbidity current event observed by seven moorings placed along Monterey Canyon, offshore central California, in the axial channel between 300 and 1900 meters water depth, a conductivity/temperature sensor placed 11 meters above canyon floor on the mooring at 1500 meters water depth recorded a rapid decrease of conductivity and increase of temperature during the passage of a large turbidity current. The conductivity decline is unlikely caused by fresh water input owing to lack of precipitation in the region prior to the event. We investigated the mechanisms of turbidity currents' high sediment concentration reducing the measured conductivity. By conducting a series of laboratory experiments with a range of different concentrations, grain size, and water temperature combinations, we quantified a relationship between reduced conductivity and the elevated sediment concentration. This relationship can be used for estimating the very high sediment concentrations in a turbidity current with a condition of assuming constant salinity of the ambient seawater. The empirical relationship was then applied to the in-situ time-series of temperature and conductivity measured during this turbidity current. The highest sediment concentration, in the head of the flow, reached nearly 400 g/L (volume concentration 17%). Such a high value, which has yet been reported in literature for an oceanic turbidity current, will have significant implications for the dynamics and deposits of such flows.

  15. Acoustic transducer in system for gas temperature measurement in gas turbine engine

    Science.gov (United States)

    DeSilva, Upul P.; Claussen, Heiko

    2017-07-04

    An apparatus for controlling operation of a gas turbine engine including at least one acoustic transmitter/receiver device located on a flow path boundary structure. The acoustic transmitter/receiver device includes an elongated sound passage defined by a surface of revolution having opposing first and second ends and a central axis extending between the first and second ends, an acoustic sound source located at the first end, and an acoustic receiver located within the sound passage between the first and second ends. The boundary structure includes an opening extending from outside the boundary structure to the flow path, and the second end of the surface of revolution is affixed to the boundary structure at the opening for passage of acoustic signals between the sound passage and the flow path.

  16. In-situ Air Temperature and Relative Humidity in Greenbelt, MD, 2013-2015

    Data.gov (United States)

    National Aeronautics and Space Administration — This data set describes the temperature and relative humidity at 12 locations around Goddard Space Flight Center in Greenbelt MD at 15 minute intervals between...

  17. In-Situ Real-Time Temperature Monitoring of Thermal Protection Systems, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — This program addresses the need for interfacial and in-depth temperature monitoring of thermal protection systems (TPS). Novel, linear drive, eddy current methods...

  18. Effective Use of Molecular Recognition in Gas Sensing: Results from Acoustic Wave and In-Situ FTIR Measurements

    Energy Technology Data Exchange (ETDEWEB)

    Bodenhofer, K,; Gopel, W.; Hierlemann, A.; Ricco, A.J.

    1998-12-09

    To probe directly the analyte/film interactions that characterize molecular recognition in gas sensors, we recorded changes to the in-situ surface vibrational spectra of specifically fictionalized surface acoustic wave (SAW) devices concurrently with analyte exposure and SAW measurement of the extent of sorption. Fourier-lmnsform infrared external- reflectance spectra (FTIR-ERS) were collected from operating 97-MH2 SAW delay lines during exposure to a range of analytes as they interacted with thin-film coatings previously shown to be selective: cyclodextrins for chiral recognition, Ni-camphorates for Lewis bases such as pyridine and organophosphonates, and phthalocyanines for aromatic compounds. In most cases where specific chemical interactions-metal coordination, "cage" compound inclusion, or z stacking-were expected, analyte dosing caused distinctive changes in the IR spectr~ together with anomalously large SAW sensor responses. In contrast, control experiments involving the physisorption of the same analytes by conventional organic polymers did not cause similar changes in the IR spectra, and the SAW responses were smaller. For a given conventional polymer, the partition coefficients (or SAW sensor signals) roughly followed the analyte fraction of saturation vapor pressure. These SAW/FTIR results support earlier conclusions derived from thickness-shear mode resonator data.

  19. A novel headspace gas chromatographic method for in situ monitoring of monomer conversion during polymerization in an emulsion environment.

    Science.gov (United States)

    Chai, Xin-Sheng; Zhong, Jin-Feng; Hu, Hui-Chao

    2012-05-18

    This paper describes a novel multiple-headspace extraction/gas chromatographic (MHE-GC) technique for monitoring monomer conversion during a polymerization reaction in a water-based emulsion environment. The polymerization reaction of methyl methacrylate (MMA) in an aqueous emulsion is used as an example. The reaction was performed in a closed headspace sample vial (as a mini-reactor), with pentane as a tracer. In situ monitoring of the vapor concentration of the tracer, employing a multiple headspace extraction (sampling) scheme, coupled to a GC, makes it possible to quantitatively follow the conversion of MMA during the early stages of polymerization. Data on the integrated amount of the tracer vapor released from the monomer droplet phase during the polymerization is described by a mathematic equation from which the monomer conversion can be calculated. The present method is simple, automated and economical, and provides an efficient tool in the investigation of the reaction kinetics and effects of the reaction conditions on the early stage of polymerization. Copyright © 2012 Elsevier B.V. All rights reserved.

  20. Heat and momentum transfer in a gas coolant flow through a circular pipe in a high temperature gas cooled reactor

    International Nuclear Information System (INIS)

    Ogawa, Masuro

    1989-07-01

    In Japan Atomic Energy Research Institute (JAERI), a very high temperature gas cooled reactor (VHTR) has been researched and developed with a purpose of attaining a coolant temperature of around 1000degC at the reactor outlet. In order to design VHTR, comprehensive knowledge is required on thermo-hydraulic characteristics of laminar-turbulent transition, of coolant flow with large thermal property variation due to temperature difference, and of heat transfer deterioration. In the present investigation, experimental and analytical studies are made on a gas flow in a circular tube to elucidate the thermo-hydraulic characteristics. Friction factors and heat transfer coefficients in transitional flows are obtained. Influence of thermal property variation on the friction factor is qualitatively determined. Heat transfer deterioration in the turbulent flow subjected to intense heating is experimentally found to be caused by flow laminarization. The analysis based on a k-kL two-equation model of turbulence predicts well the experimental results on friction factors and heat transfer coefficients in flows with thermal property variation and in laminarizing flows. (author)

  1. Spatiotemporal Evaluation of Reanalysis and In-situ Surface Air Temperature over Ethiopia

    Science.gov (United States)

    Tesfaye, T.

    2017-12-01

    Tewodros Woldemariam Tesfaye*1, C.T. Dhanya 2,and A.K. Gosain3 1Research Scholar, Department of Civil Engineering, Indian Institute of Technology Delhi, New Delhi-110016, India 2Assistant Professor, Department of Civil Engineering, Indian Institute of Technology Delhi, New Delhi-110016, India 3 Professor, Department of Civil Engineering, Indian Institute of Technology Delhi, New Delhi-110016, India, *e-mail: tewodros2002@gmail.com Abstract: Water resources management and modelling studies are often constrained by the scarcity of observed data, especially of the two major variables i.e., precipitation and temperature. Modellers, hence, rely on reanalysis datasets as a substitute; though its performance heavily vary depending on the data availability and regional characteristics. The present study aims at examining the ability of frequently used reanalysis datasets in capturing the spatiotemporal characteristics of maximum and minimum surface temperatures over Ethiopia and to highlight the biases, if any, in these over Ethiopian region. We considered ERA-Interim, NCEP 2, MERRA and CFSR reanalysis datasets and compared these with temperature observations from 15 synoptic stations spread over Ethiopia. In addition to the long term averages and annual cycle, a critical comparison of various extreme indices such as diurnal temperature range, warm days, warm nights, cool days, cool nights, summer days and tropical nights are also undertaken. Our results indicate that, the performance of CFSR followed by NCEP 2 is better in capturing majority of the aspects. ERA-Interim suffers a huge additive bias in the simulation of various aspects of minimum temperature in all the stations considered; while its performance is better for maximum temperature. The inferior performance of ERA-Interim is noted to be only because of the difficulty in simulating minimum temperature. Key words: ERA Interim; NCEP Reanalysis; MERRA; CFSR; Diurnal temperature range; reanalysis performance.

  2. Mass flow discharge and total temperature characterisation of a pyrotechnic gas generator formulation for airbag systems

    Energy Technology Data Exchange (ETDEWEB)

    Neutz, Jochen; Koenig, Andreas [Fraunhofer Institut fuer Chemische Technologie ICT, Pfinztal (Germany); Knauss, Helmut; Jordan, Sebastian; Roediger, Tim; Smorodsky, Boris [Universitaet Stuttgart (Germany). Institut fuer Aerodynamik und Gasdynamik; Bluemcke, Erich Walter [AUDI AG, Department I/EK-523, Ingolstadt (Germany)

    2009-06-15

    The mass flow characteristics of gas generators for airbag applications have to comply with a number of requirements for an optimal deployment of the airbag itself. Up to now, the mass flow was determined from pressure time histories of so-called can tests. This procedure suffers from the missing knowledge on the temperature of the generated gas entering the can. A new test setup described in this paper could overcome this problem by providing highly time resolved information on the gas's total temperature and the mass flow of the generator. The test setup consisted of a combustion chamber with a specially designed Laval nozzle in combination with a temperature sensor of high time resolution. The results showed a high time resolved temperature signal, which was disturbed by the formation of a slag layer on the sensor. Plausibility considerations with experimentally and thermodynamically determined combustion temperatures led to satisfying results for the overall temperature as characteristic parameter of airbag inflating gases flows from pyrotechnics. (Abstract Copyright [2009], Wiley Periodicals, Inc.)

  3. In-situ Elevated Temperature Mechanical Performance of MWCNT/epoxy Nanocomposite

    Directory of Open Access Journals (Sweden)

    Bhanu Pratap Singh

    2017-03-01

    Full Text Available The present investigation has been focused on the effects of multi-walled carbon nanotube (MWCNT addition on the mechanical performance of epoxy under different in-service elevated temperature environments. Room temperature flexural test results revealed that addition of 0.1 wt. % MWCNT into epoxy resin resulted in modulus and strength enhancement of 21 % and 9 % respectively. With increase in service temperature, significant decrement in both modulus and strength was noticed for both materials (neat epoxy and MWCNT/epoxy nanocomposite, but the rate of degradation was found to be quite drastic for the nanocomposite. At 90 °C temperature, the CNT/epoxy nanocomposite exhibited inferior modulus and strength, which are 41 % and 59 % lower than neat epoxy respectively. The variation trend in elastic modulus with temperature obtained from both flexural testing and DMA for both these materials was also analyzed. It was found that addition of 0.1 % CNT in the epoxy reduced the glass transition temperature by about 16°C.

  4. Landscape Evolution Mechanisms in Gale Crater from In-Situ Measurement of Cosmogenic Noble Gas Isotopes

    Science.gov (United States)

    Martin, P.; Farley, K. A.; Mahaffy, P. R.; Malespin, C.; Vasconcelos, P. M.

    2017-12-01

    The Sample Analysis at Mars (SAM) instrument onboard the Curiosity rover can measure the noble gas isotopes contained in drilled rock samples on Mars by heating these samples to 930°C. In combination with bulk chemistry measured by the Alpha Particle X-ray Spectrometer (APXS), cosmogenic nuclide production rates can be determined and an exposure age may be calculated. Three cosmogenic nuclides are measured: 3He, and 21Ne, which are produced via spallation of mainly O, Mg, Si, and Al (held mostly in detrital grains); and 36Ar, which is produced from neutron capture of 35Cl (held mostly in secondary materials). To date, three samples have been measured: Cumberland (CB), Windjana (WJ), and Mojave 2 (MJ2). CB yielded 3He, 21Ne, and 36Ar ages of 72 ± 15, 84 ± 28, and 79 ± 24 Ma, respectively [Farley et al., 2014]. Two aliquots of WJ gave error-weighted mean ages of 30 ± 27 Ma (3He), 54 ± 19 Ma (21Ne), and 63 ± 84 Ma (36Ar) [Vasconcelos et al., 2016]. These relatively young ages were interpreted to suggest that a scarp-retreat mechanism is responsible for erosion at both the CB and WJ localities. The most recent measurements on MJ2 do not include the 21Ne isotope because of an instrument issue at this mass. 3He observed in MJ2 is the highest of any sample yet measured, suggesting an exposure age of approximately 1 Ga. In contrast, the calculated exposure age from 36Ar appears to be less than 100 Ma (despite a high uncertainty due to isobaric H35Cl). This discrepancy could be explained by 1) a contribution of extraterrestrial 3He from interplanetary dust or meteoritic fragments, or 2) approximately 1 Ga of prior exposure to the detrital grains. In the latter case 36Ar accumulates only after the Cl-bearing secondary minerals are formed and exposed at the surface. In either scenario the 36Ar measurement provides the better estimate of the recent exposure history. The young upper limit for 36Ar at MJ2 is consistent with the scarp-retreat mechanism observed at CB and

  5. High temperature hydrogen sulfide adsorption on activated carbon - I. Effects of gas composition and metal addition

    Science.gov (United States)

    Cal, M.P.; Strickler, B.W.; Lizzio, A.A.

    2000-01-01

    Various types of activated carbon sorbents were evaluated for their ability to remove H2S from a simulated coal gas stream at a temperature of 550 ??C. The ability of activated carbon to remove H2S at elevated temperature was examined as a function of carbon surface chemistry (oxidation, thermal desorption, and metal addition), and gas composition. A sorbent prepared by steam activation, HNO3 oxidation and impregnated with Zn, and tested in a gas stream containing 0.5% H2S, 50% CO2 and 49.5% N2, had the greatest H2S adsorption capacity. Addition of H2, CO, and H2O to the inlet gas stream reduced H2S breakthrough time and H2S adsorption capacity. A Zn impregnated activated carbon, when tested using a simulated coal gas containing 0.5% H2S, 49.5% N2, 13% H2, 8.5% H2O, 21% CO, and 7.5% CO2, had a breakthrough time of 75 min, which was less than 25 percent of the length of breakthrough for screening experiments performed with a simplified gas mixture of 0.5% H2S, 50% CO2, and 49.5% N2.

  6. Analysis of Precooling Injection Transient of Steam Generator for High Temperature Gas Cooled Reactor

    Directory of Open Access Journals (Sweden)

    Yan Wang

    2017-01-01

    Full Text Available After a postulated design basis accident leads high temperature gas cooled reactor to emergency shutdown, steam generator still remains with high temperature level and needs to be cooled down by a precooling before reactor restarts with clearing of fault. For the large difference of coolant temperature between inlet and outlet of steam generator in normal operation, the temperature distribution on the components of steam generator is very complicated. Therefore, the temperature descending rate of the components in steam generator needs to be limited to avoid the potential damage during the precooling stage. In this paper, a pebble-bed high temperature gas cooled reactor is modeled by thermal-hydraulic system analysis code and several postulated precooling injection transients are simulated and compared to evaluate their effects, which will provide support for the precooling design. The analysis results show that enough precooling injection is necessary to satisfy the precooling requirements, and larger mass flow rate of precooling water injection will accelerate the precooling process. The temperature decrease of steam generator is related to the precooling injection scenarios, and the maximal mass flow rate of the precooling injection should be limited to avoid the excessively quick temperature change of the structures in steam generator.

  7. Long wavelength infrared radiation thermometry for non-contact temperature measurements in gas turbines

    Science.gov (United States)

    Manara, J.; Zipf, M.; Stark, T.; Arduini, M.; Ebert, H.-P.; Tutschke, A.; Hallam, A.; Hanspal, J.; Langley, M.; Hodge, D.; Hartmann, J.

    2017-01-01

    The objective of the EU project "Sensors Towards Advanced Monitoring and Control of Gas Turbine Engines (acronym STARGATE)" is the development of a suite of advanced sensors, instrumentation and related systems in order to contribute to the developing of the next generation of green and efficient gas turbine engines. One work package of the project deals with the design and development of a long wavelength infrared (LWIR) radiation thermometer for the non-contact measurement of the surface temperature of thermal barrier coatings (TBCs) during the operation of gas turbine engines. For opaque surfaces (e.g. metals or superalloys) radiation thermometers which are sensitive in the near or short wavelength infrared are used as state-of-the-art method for non-contact temperature measurements. But this is not suitable for oxide ceramic based TBCs (e.g. partially yttria stabilized zirconia) as oxide ceramics are semi-transparent in the near and short wavelength infrared spectral region. Fortunately the applied ceramic materials are non-transparent in the long wavelength infrared and additionally exhibit a high emittance in this wavelength region. Therefore, a LWIR pyrometer can be used for non-contact temperature measurements of the surfaces of TBCs as such pyrometers overcome the described limitation of existing techniques. For performing non-contact temperature measurements in gas turbines one has to know the infrared-optical properties of the applied TBCs as well as of the hot combustion gas in order to properly analyse the measurement data. For reaching a low uncertainty on the one hand the emittance of the TBC should be high (>0.9) in order to reduce reflections from the hot surrounding and on the other hand the absorbance of the hot combustion gas should be low (<0.1) in order to decrease the influence of the gas on the measured signal. This paper presents the results of the work performed by the authors with focus on the implementation of the LWIR pyrometer and the

  8. Interstellar Gas Flow Vector and Temperature Determination over 5 Years of IBEX Observations

    International Nuclear Information System (INIS)

    Möbius, E; Heirtzler, D; Kucharek, H; Lee, M A; Leonard, T; Schwadron, N; Bzowski, M; Kubiak, M A; Sokół, J M; Fuselier, S A; McComas, D J; Wurz, P

    2015-01-01

    The Interstellar Boundary Explorer (IBEX) observes the interstellar neutral gas flow trajectories at their perihelion in Earth's orbit every year from December through early April, when the Earth's orbital motion is into the oncoming flow. These observations have defined a narrow region of possible, but very tightly coupled interstellar neutral flow parameters, with inflow speed, latitude, and temperature as well-defined functions of inflow longitude. The best- fit flow vector is different by ≈ 3° and lower by ≈ 3 km/s than obtained previously with Ulysses GAS, but the temperature is comparable. The possible coupled parameter space reaches to the previous flow vector, but only for a substantially higher temperature (by ≈ 2000 K). Along with recent pickup ion observations and including historical observations of the interstellar gas, these findings have led to a discussion, whether the interstellar gas flow into the solar system has been stable or variable over time. These intriguing possibilities call for more detailed analysis and a longer database. IBEX has accumulated observations over six interstellar flow seasons. We review key observations and refinements in the analysis, in particular, towards narrowing the uncertainties in the temperature determination. We also address ongoing attempts to optimize the flow vector determination through varying the IBEX spacecraft pointing and discuss related implications for the local interstellar cloud and its interaction with the heliosphere

  9. Design activity of IHI on the experimental multipurpose high temperature gas-cooled reactor

    International Nuclear Information System (INIS)

    1978-01-01

    With conspicuous interest and attention paid by iron and steel manufacturing industries, the development of the multipurpose high temperature gas-cooled reactor, namely the process heat reactor has been energetically discussed in Japan. The experimental multipurpose high temperature gas-cooled reactor, planned by JAERI (the Japan Atomic Energy Research Institute), is now at the end of the adjustment design stage and about to enter the system synthesizing design stage. The design of the JAERI reactor as a pilot plant for process heat reactors that make possible the direct use of the heat, produced in the reactor, for other industrial uses was started in 1969, and has undergone several revisions up to now. The criticality of the JAERI reactor is expected to be realized before 1985 according to the presently published program. IHI has engaged in the developing work of HTGR (high temperature gas-cooled reactor) including VHTR (very high temperature gas-cooled reactor) for over seven years, producing several achievements. IHI has also participated in the JAERI project since 1973 with some other companies concerned in this field. The design activity of IHI in the development of the JAERI reactor is briefly presented in this paper. (auth.)

  10. Megawatt low-temperature DC plasma generator with divergent channels of gas-discharge tract

    Science.gov (United States)

    Gadzhiev, M. Kh.; Isakaev, E. Kh.; Tyuftyaev, A. S.; Yusupov, D. I.; Sargsyan, M. A.

    2017-04-01

    We have developed and studied a new effective megawatt double-unit generator of low-temperature argon plasma, which belongs to the class of dc plasmatrons and comprises the cathode and anode units with divergent gas-discharge channels. The generator has an efficiency of about 80-85% and ensures a long working life at operating currents up to 4000 A.

  11. Large-volume injection in gas chromatographic trace analysis using temperature-programmable (PTV) injectors

    NARCIS (Netherlands)

    Mol, J.G.J.; Janssen, J.G.M.; Cramers, C.A.M.G.; Brinkman, U.A.T.

    1996-01-01

    The use of programmed-temperature vaporising (PTV) injectors for large-volume injection in capillary gas chromatography is briefly reviewed. The principles and optimisation of large-volume PTV injection are discussed. Guidelines are given for selection of the PTV conditions and injection mode for

  12. Sodium and cover gas chemistry in the high temperature sodium facility

    International Nuclear Information System (INIS)

    McCown, J.J.; Duncan, H.C.

    1976-01-01

    The equipment and procedures used in following sodium and cover gas chemistry changes in the High Temperature Sodium Facility are presented. The methods of analysis and results obtained are given. Impurity trends which have been measured during the facility operations are discussed

  13. Technology development for the modular high-temperature gas-cooled reactor

    International Nuclear Information System (INIS)

    Homan, F.J.; Turner, R.F.

    1989-01-01

    In the USA the Modular High-Temperature Gas-Cooled Reactor is in an advanced stage of design. The related HTGR program areas, the approaches to these programs along with sample results and a description of how these data are used are highlighted in the paper. (author). Figs and tabs

  14. Detection of H2S gas at lower operating temperature using sprayed ...

    Indian Academy of Sciences (India)

    Nanostructured In2O3; thin films; spray pyrolysis; H2S gas sensor; low temperature. 1. Introduction ... nozzle to and fro frequency (16 cycles/min), nozzle to sub- ... were confirmed by measuring the thermoelectric power of the thin film samples.

  15. Temperature Evolution of a 1 MA Triple-Nozzle Gas-Puff Z-Pinch

    Science.gov (United States)

    de Grouchy, Philip; Banasek, Jacob; Engelbrecht, Joey; Qi, Niansheng; Atoyan, Levon; Byvank, Tom; Cahill, Adam; Moore, Hannah; Potter, William; Ransohoff, Lauren; Hammer, David; Kusse, Bruce; Laboratory of Plasma Studies Team

    2015-11-01

    Mitigation of the Rayleigh-Taylor instability (RTI) plays a critical role in optimizing x-ray output at high-energy ~ 13 keV using the triple-nozzle Krypton gas-puff at Sandia National Laboratory. RTI mitigation by gas-puff density profiling using a triple-nozzle gas-puff valve has recently been recently demonstrated on the COBRA 1MA z-pinch at Cornell University. In support of this work we investigate the role of shell cooling in the growth of RTI during gas-puff implosions. Temperature measurements within the imploding plasma shell are recorded using a 527 nm, 10 GW Thomson scattering diagnostic for Neon, Argon and Krypton puffs. The mass-density profile is held constant at 22 microgram per centimeter for all three puffs and the temperature evolution of the imploding material is recorded. In the case of Argon puffs we find that the shell ion and electron effective temperatures remain in equilibrium at around 1keV for the majority of the implosion phase. In contrast scattered spectra from Krypton are dominated by of order 10 keV effective ion temperatures. Supported by the NNSA Stewardship Sciences Academic Programs.

  16. Design of project management system for 10 MW high temperature gas-cooled test reactor

    International Nuclear Information System (INIS)

    Zhu Yan; Xu Yuanhui

    1998-01-01

    A framework of project management information system (MIS) for 10 MW high temperature gas-cooled test reactor is introduced. Based on it, the design of nuclear project management information system and project monitoring system (PMS) are given. Additionally, a new method of developing MIS and Decision Support System (DSS) has been tried

  17. Summary of ORNL high-temperature gas-cooled reactor program

    International Nuclear Information System (INIS)

    Kasten, P.R.

    1981-01-01

    Oak Ridge National Laboratory (ORNL) efforts on the High-Temperature Gas-Cooled Reactor (HTGR) Program have been on HTGR fuel development, fission product and coolant chemistry, prestressed concrete reactor vessel (PCRV) studies, materials studies, graphite development, reactor physics and shielding studies, application assessments and evaluations and selected component testing

  18. Trends in low-temperature water–gas shift reactivity on transition metals

    DEFF Research Database (Denmark)

    Schumacher, Nana Maria Pii; Boisen, Astrid; Dahl, Søren

    2005-01-01

    Low-temperature water–gas shift reactivity trends on transition metals were investigated with the use of a microkinetic model based on a redox mechanism. It is established that the adsorption energies for carbon monoxide and oxygen can describe to a large extent changes in the remaining activation...

  19. Robust control of speed and temperature in a power plant gas turbine.

    Science.gov (United States)

    Najimi, Ebrahim; Ramezani, Mohammad Hossein

    2012-03-01

    In this paper, an H(∞) robust controller has been designed for an identified model of MONTAZER GHAEM power plant gas turbine (GE9001E). In design phase, a linear model (ARX model) which is obtained using real data has been applied. Since the turbine has been used in a combined cycle power plant, its speed and also the exhaust gas temperature should be adjusted simultaneously by controlling fuel signals and compressor inlet guide vane (IGV) position. Considering the limitations on the system inputs, the aim of the control is to maintain the turbine speed and the exhaust gas temperature within desired interval under uncertainties and load demand disturbances. Simulation results of applying the proposed robust controller on the nonlinear model of the system (NARX model), fairly fulfilled the predefined aims. Simulations also show the improvement in the performance compared to MPC and PID controllers for the same conditions. Copyright © 2011 ISA. Published by Elsevier Ltd. All rights reserved.

  20. Preliminary analysis of combined cycle of modular high-temperature gas cooled reactor

    International Nuclear Information System (INIS)

    Baogang, Z.; Xiaoyong, Y.; Jie, W.; Gang, Z.; Qian, S.

    2015-01-01

    Modular high-temperature gas cooled reactor (HTGR) is known as one of the most advanced nuclear reactors because of its inherent safety and high efficiency. The power conversion system of HTGR can be steam turbine based on Rankine cycle or gas turbine based on Brayton cycle respectively. The steam turbine system is mature and the gas turbine system has high efficiency but under development. The Brayton-Rankine combined cycle is an effective way to further promote the efficiency. This paper investigated the performance of combined cycle from the viewpoint of thermodynamics. The effect of non-dimensional parameters on combined cycle’s efficiency, such as temperature ratio, compression ratio, efficiency of compressor, efficiency of turbine, was analyzed. Furthermore, the optimal parameters to achieve highest efficiency was also given by this analysis under engineering constraints. The conclusions could be helpful to the design and development of combined cycle of HTGR. (author)

  1. Spatially Resolved Gas Temperature Measurements in an Atmospheric Pressure DC Glow Microdischarge with Raman Scattering

    Science.gov (United States)

    Belostotskiy, S.; Wang, Q.; Donnelly, V.; Economou, D.; Sadeghi, N.

    2006-10-01

    Spatially resolved rotational Raman spectroscopy of ground state nitrogen N2(X^1σg^+) was used to measure the gas temperature (Tg) in a nitrogen dc glow microdischarge (gap between electrodes d˜500 μm). An original backscattering, confocal optical system was developed for collecting Raman spectra. Stray laser light and Raleigh scattering were blocked by using a triple grating monochromator and spatial filters, designed specifically for these experiments. The optical system provided a spatial resolution of electrodes, Tg increased linearly with jd, reaching 500 K at 1000 mA/cm^2 jd for a pressure of 720 Torr. Spatially resolved gas temperature measurements will also be presented and discussed in combination with a mathematical model for gas heating in the microplasma. This work is supported by DoE/NSF.

  2. Heat exchanger for transfering heat produced in a high temperature reactor to an intermediate circuit gas

    International Nuclear Information System (INIS)

    Barchewitz, E.; Baumgaertner, H.

    1985-01-01

    The invention is concerned with improving the arrangement of a heat exchanger designed to transfer heat from the coolant gas circuit of a high temperature reactor to a gas which is to be used for a process heat plant. In the plant the material stresses are to be kept low at high differential pressures and temperatures. According to the invention the tube bundles designed as boxes are fixed within the heat exchanger closure by means of supply pipes having got loops. For conducting the hot gas the heat exchanger has got a central pipe leading out of the reactor vessel through the pod closure and having got only one point of fixation, lying in this closure. Additional advantageous designs are mentioned. (orig./PW)

  3. Thermodynamic data for selected gas impurities in the primary coolant of high-temperature gas-cooled reactors

    International Nuclear Information System (INIS)

    Feber, R.C.

    1976-12-01

    The literature of thermodynamic data for selected fission-product species is reviewed and supplemented in support of complex chemical equilibrium calculations applied to fission-product distributions in the primary coolant of high-temperature gas-cooled reactors. Thermodynamic functions and heats and free energies of formation are calculated and tabulated to 3000 0 K for CsI (s,l,g), Cs 2 I 2 (g), CH 3 I(g), COI 2 (g), and CsH(g). 79 references

  4. Long Term Validation of Land Surface Temperature Retrieved from MSG/SEVIRI with Continuous in-Situ Measurements in Africa

    Directory of Open Access Journals (Sweden)

    Frank-M. Göttsche

    2016-05-01

    Full Text Available Since 2005, the Land Surface Analysis Satellite Application Facility (LSA SAF operationally retrieves Land Surface Temperature (LST for the Spinning Enhanced Visible and Infrared Imager (SEVIRI on board Meteosat Second Generation (MSG. The high temporal resolution of the Meteosat satellites and their long term availability since 1977 make their data highly valuable for climate studies. In order to ensure that the LSA SAF LST product continuously meets its target accuracy of 2 °C, it is validated with in-situ measurements from four dedicated LST validation stations. Three stations are located in highly homogenous areas in Africa (semiarid bush, desert, and Kalahari semi-desert and typically provide thousands of monthly match-ups with LSA SAF LST, which are used to perform seasonally resolved validations. An uncertainty analysis performed for desert station Gobabeb yielded an estimate of total in-situ LST uncertainty of 0.8 ± 0.12 °C. Ignoring rainy seasons, the results for the period 2009–2014 show that LSA SAF LST consistently meets its target accuracy: the highest mean root-mean-square error (RMSE for LSA SAF LST over the African stations was 1.6 °C while mean absolute bias was 0.1 °C. Nighttime and daytime biases were up to 0.7 °C but had opposite signs: when evaluated together, these partially compensated each other.

  5. Gas leak tightness of SiC/SiC composites at elevated temperature

    Energy Technology Data Exchange (ETDEWEB)

    Hayasaka, Daisuke, E-mail: hayasaka@oasis.muroran-it.ac.jp [OASIS, Muroran Institute of Technology, Muroran, Hokkaido (Japan); Graduate School of Engineering, Muroran Institute of Technology, Muroran, Hokkaido (Japan); Park, Joon-Soo. [OASIS, Muroran Institute of Technology, Muroran, Hokkaido (Japan); Kishimoto, Hirotatsu [OASIS, Muroran Institute of Technology, Muroran, Hokkaido (Japan); Graduate School of Engineering, Muroran Institute of Technology, Muroran, Hokkaido (Japan); Kohyama, Akira [OASIS, Muroran Institute of Technology, Muroran, Hokkaido (Japan)

    2016-11-01

    Highlights: • NITE-SiC/SiC has extremely densified microstructure compared with other SiC/SiC composite like CVI. • Excellent helium and hydrogen gas-leak tightness of SiC/SiC composites by DEMO-NITE method from prototype industrialization production line was presented. • The excellence against stainless steel and Zircaloy at elevated temperature, together with generic excellent properties of SiC will be inevitable for innovative blanket and divertors for DEMO- and power- fusion reactors. - Abstract: SiC/SiC composite materials are attractive candidates for high heat flux components and blanket of fusion reactor, mainly due to their high temperature properties, radiation damage tolerance and low induced radioactivity. One of the challenges for SiC/SiC application in fusion reactors is to satisfy sufficient gas leak tightness of hydrogen and helium isotopes. Although many efforts have been carried-out, SiC/SiC composites by conventional processes have not been successful to satisfy the requirements, except SiC/SiC composites by NITE-methods. Toward the early realization of SiC/SiC components into fusion reactor systems process development of NITE-process has been continued. Followed to the brief introduction of recently developed DEMO-NITE process, baseline properties and hydrogen and helium gas leak tightness is presented. SiC/SiC claddings with 10 mm in diameter and 1 mm in wall thickness are tested by gas leak tightness system developed. The leak tightness measurements are done room temperature to 400 °C. Excellent gas leak tightness equivalent or superior to Zircaloy claddings for light water fission reactors is confirmed. The excellent gas leak tightness suggests nearly perfect suppression of large gas leak path in DEMO-NITE SiC/SiC.

  6. Gas reactor and associated nuclear experience in the UK relevant to high temperature reactor engineering

    International Nuclear Information System (INIS)

    Beech, D.J.; May, R.

    2000-01-01

    In the UK, the NNC played a leading role in the design and build of all of the UK's commercial magnox reactors and advanced gas-cooled reactors (AGRs). It was also involved in the DRAGON project and was responsible for producing designs for large scale HTRs and other gas reactor designs employing helium and carbon dioxide coolants. This paper addresses the gas reactor experience and its relevance to the current HTR designs under development which use helium as the coolant, through the consideration of a representative sample of the issues addressed in the UK by the NNC in support of the AGR and other reactor programmes. Modern HTR designs provide unique engineering challenges. The success of the AGR design, reflected in the extended lifetimes agreed upon by the licensing authorities at many stations, indicates that these challenges can be successfully overcome. The UK experience is unique and provides substantial support to future gas reactor and high temperature engineering studies. (authors)

  7. In-situ Monitoring of Internal Local Temperature and Voltage of Proton Exchange Membrane Fuel Cells

    Directory of Open Access Journals (Sweden)

    Chi-Yuan Lee

    2010-06-01

    Full Text Available The distribution of temperature and voltage of a fuel cell are key factors that influence performance. Conventional sensors are normally large, and are also useful only for making external measurements of fuel cells. Centimeter-scale sensors for making invasive measurements are frequently unable to accurately measure the interior changes of a fuel cell. This work focuses mainly on fabricating flexible multi-functional microsensors (for temperature and voltage to measure variations in the local temperature and voltage of proton exchange membrane fuel cells (PEMFC that are based on micro-electro-mechanical systems (MEMS. The power density at 0.5 V without a sensor is 450 mW/cm2, and that with a sensor is 426 mW/cm2. Since the reaction area of a fuel cell with a sensor is approximately 12% smaller than that without a sensor, but the performance of the former is only 5% worse.

  8. In-situ monitoring of internal local temperature and voltage of proton exchange membrane fuel cells.

    Science.gov (United States)

    Lee, Chi-Yuan; Fan, Wei-Yuan; Hsieh, Wei-Jung

    2010-01-01

    The distribution of temperature and voltage of a fuel cell are key factors that influence performance. Conventional sensors are normally large, and are also useful only for making external measurements of fuel cells. Centimeter-scale sensors for making invasive measurements are frequently unable to accurately measure the interior changes of a fuel cell. This work focuses mainly on fabricating flexible multi-functional microsensors (for temperature and voltage) to measure variations in the local temperature and voltage of proton exchange membrane fuel cells (PEMFC) that are based on micro-electro-mechanical systems (MEMS). The power density at 0.5 V without a sensor is 450 mW/cm(2), and that with a sensor is 426 mW/cm(2). Since the reaction area of a fuel cell with a sensor is approximately 12% smaller than that without a sensor, but the performance of the former is only 5% worse.

  9. A variable temperature cryostat that produces in situ clean-up germanium detector surfaces

    International Nuclear Information System (INIS)

    Pehl, R.H.; Madden, N.W.; Malone, D.F.; Cork, C.P.; Landis, D.A.; Xing, J.S.; Friesel, D.L.

    1988-11-01

    Variable temperature cryostats that can maintain germanium detectors at temperatures from 82 K to about 400 K while the thermal shield surrounding the detectors remains much colder when the detectors are warmed have been developed. Cryostats such as these offer the possibility of cryopumping material from the surface of detectors to the colder thermal shield. The diode characteristics of several detectors have shown very significant improvement following thermal cycles up to about 150 K in these cryostats. Important applications for cryostats having this attribute are many. 4 figs

  10. High-temperature elastic properties of in situ-reinforced Si3N4

    International Nuclear Information System (INIS)

    Swift, Geoffrey A.; Uestuendag, Ersan; Clausen, Bjoern; Bourke, Mark A.M.; Lin, H.-T.

    2003-01-01

    A high-temperature tensile stress study of a monolithic silicon nitride (Si 3 N 4 ) was performed with time-of-flight neutron diffraction. A dedicated engineering diffractometer was employed at temperatures reaching 1375 deg. C. Rietveld refinements of diffraction spectra allowed the determination of (1) the coefficient of thermal expansion tensor during heating and (2) lattice strains during loading. The stress-strain response of individual lattice reflections was used to calculate the single-crystal elastic stiffness tensor of Si 3 N 4 at 1375 deg. C via a self-consistent model

  11. Temperature and coupling dependence of the universal contact intensity for an ultracold Fermi gas

    International Nuclear Information System (INIS)

    Palestini, F.; Perali, A.; Pieri, P.; Strinati, G. C.

    2010-01-01

    Physical properties of an ultracold Fermi gas in the temperature-coupling phase diagram can be characterized by the contact intensity C, which enters the pair-correlation function at short distances and describes how the two-body problem merges into its surrounding. We show that the local order established by pairing fluctuations about the critical temperature T c of the superfluid transition considerably enhances the contact C in a temperature range where pseudogap phenomena are maximal. Our ab initio results for C in a trap compare well with recently available experimental data over a wide coupling range. An analysis is also provided for the effects of trap averaging on C.

  12. High temperature and high pressure gas cell for quantitative spectroscopic measurements

    DEFF Research Database (Denmark)

    Christiansen, Caspar; Stolberg-Rohr, Thomine; Fateev, Alexander

    2016-01-01

    A high temperature and high pressure gas cell (HTPGC) has been manufactured for quantitative spectroscopic measurements in the pressure range 1-200 bar and temperature range 300-1300 K. In the present work the cell was employed at up to 100 bar and 1000 K, and measured absorption coefficients...... of a CO2-N2 mixture at 100 bar and 1000 K are revealed for the first time, exceeding the high temperature and pressure combinations previously reported. This paper discusses the design considerations involved in the construction of the cell and presents validation measurements compared against simulated...

  13. Method and alloys for fabricating wrought components for high-temperature gas-cooled reactors

    International Nuclear Information System (INIS)

    Thompson, L.D.; Johnson, W.R.

    1983-01-01

    Wrought, nickel-based alloys, suitable for components of a high-temperature gas-cooled reactor exhibit strength and excellent resistance to carburization at elevated temperatures and include aluminum and titanium in amounts and ratios to promote the growth of carburization resistant films while preserving the wrought character of the alloys. These alloys also include substantial amounts of molybdenum and/or tungsten as solid-solution strengtheners. Chromium may be included in concentrations less than 10% to assist in fabrication. Minor amounts of carbon and one or more carbide-forming metals also contribute to high-temperature strength. The range of compositions of these alloys is given. (author)

  14. Influence of gas atmospheres and ceria on the stability of nanoporous gold studied by environmental electron microscopy and In situ ptychography

    DEFF Research Database (Denmark)

    Baier, Sina; Wittstock, Arne; Damsgaard, Christian Danvad

    2016-01-01

    A novel complementary approach of electron microscopy/environmental TEM and in situ hard X-ray ptychography was used to study the thermally induced coarsening of nanoporous gold under different atmospheres, pressures and after ceria deposition. The temperature applied during ptychographic imaging...

  15. In situ observations of the atomistic mechanisms of Ni catalyzed low temperature graphene growth.

    Science.gov (United States)

    Patera, Laerte L; Africh, Cristina; Weatherup, Robert S; Blume, Raoul; Bhardwaj, Sunil; Castellarin-Cudia, Carla; Knop-Gericke, Axel; Schloegl, Robert; Comelli, Giovanni; Hofmann, Stephan; Cepek, Cinzia

    2013-09-24

    The key atomistic mechanisms of graphene formation on Ni for technologically relevant hydrocarbon exposures below 600 °C are directly revealed via complementary in situ scanning tunneling microscopy and X-ray photoelectron spectroscopy. For clean Ni(111) below 500 °C, two different surface carbide (Ni2C) conversion mechanisms are dominant which both yield epitaxial graphene, whereas above 500 °C, graphene predominantly grows directly on Ni(111) via replacement mechanisms leading to embedded epitaxial and/or rotated graphene domains. Upon cooling, additional carbon structures form exclusively underneath rotated graphene domains. The dominant graphene growth mechanism also critically depends on the near-surface carbon concentration and hence is intimately linked to the full history of the catalyst and all possible sources of contamination. The detailed XPS fingerprinting of these processes allows a direct link to high pressure XPS measurements of a wide range of growth conditions, including polycrystalline Ni catalysts and recipes commonly used in industrial reactors for graphene and carbon nanotube CVD. This enables an unambiguous and consistent interpretation of prior literature and an assessment of how the quality/structure of as-grown carbon nanostructures relates to the growth modes.

  16. N-Vinylcarbazole: As an Additive for Thermal Polymerization at Room Temperature with in situ Formation of Ag(0 Nanoparticules

    Directory of Open Access Journals (Sweden)

    Mohamad-Ali Tehfe

    2015-08-01

    Full Text Available N-vinylcarbazole (NVK is proposed as an additive for acrylates thermal free radical polymerization (FRP and epoxy thermal ring opening polymerization (ROP at room temperature. The new initiating systems are based on a silane/silver salt/N-vinylcarbazole interaction, which ensures good to excellent polymerization. Moreover, the polymerization is much more efficient under air than under argon. The effects of the N-vinylcarbazole, silane, silver salt and monomer structures are investigated. Interestingly, silver nanoparticles Ag(0 are formed in situ. The as-synthesized nanocomposite materials contained spherical nanoparticles homogeneously dispersed in the polymer matrices. Polymers and nanoparticles were characterized by Differential Scanning Calorimetry (DSC, Transmission Electron Microscopy (TEM, Energy-Dispersive X-ray Spectrometry (EDS, Fourier Transform Infrared Spectroscopy (FTIR, and UV-vis spectroscopy. A coherent picture of the involved chemical mechanisms is presented.

  17. Evolution of Western Mediterranean Sea Surface Temperature between 1985 and 2005: a complementary study in situ, satellite and modelling approaches

    Science.gov (United States)

    Troupin, C.; Lenartz, F.; Sirjacobs, D.; Alvera-Azcárate, A.; Barth, A.; Ouberdous, M.; Beckers, J.-M.

    2009-04-01

    In order to evaluate the variability of the sea surface temperature (SST) in the Western Mediterranean Sea between 1985 and 2005, an integrated approach combining geostatistical tools and modelling techniques has been set up. The objectives are: underline the capability of each tool to capture characteristic phenomena, compare and assess the quality of their outputs, infer an interannual trend from the results. Diva (Data Interpolating Variationnal Analysis, Brasseur et al. (1996) Deep-Sea Res.) was applied on a collection of in situ data gathered from various sources (World Ocean Database 2005, Hydrobase2, Coriolis and MedAtlas2), from which duplicates and suspect values were removed. This provided monthly gridded fields in the region of interest. Heterogeneous time data coverage was taken into account by computing and removing the annual trend, provided by Diva detrending tool. Heterogeneous correlation length was applied through an advection constraint. Statistical technique DINEOF (Data Interpolation with Empirical Orthogonal Functions, Alvera-Azc

  18. Phase transformation in sol-gel prepared zirconia using in-situ high temperature X-ray diffraction

    International Nuclear Information System (INIS)

    Srinivasan, R.; Davis, B.H.; Hubbard, C.R.; Cavin, O.B.; Porter, W.D.

    1991-01-01

    Zirconia was precipitated at a pH of 10.5 by admixing a solution of ZrCl 4 and NH 4 OH both rapidly (∼ 1 min) and slowly (∼ 8 hr). The precipitate was calcined at 500C for 5 hours and then furnace cooled. The former exhibited monoclinic phase while the latter yielded tetragonal phase. The pathway from amorphous to crystalline form was followed by in-situ high temperature X-ray diffraction in flowing air and in He. The data showed the evolution of the tetragonal crystalline phase on heating. On rapid cooling the tetragonal phase is retained at R.T., and on slow cooling the transformation to monoclinic phase occurs in air

  19. Oxygen partial pressure control during in-situ high temperature X-ray diffraction on cerium dioxide

    International Nuclear Information System (INIS)

    Strach, M.; Belin, R.C.; Richaud, J-C.; Rogez, J.

    2014-01-01

    Cerium dioxide is widely used as a surrogate for plutonium dioxide in the studies of MOX type nuclear fuel. Thus, obtaining an accurate description of the structures present in this system in a range of temperatures is of importance to the development of fuel for the IV. generation of nuclear reactors. However, such a study requires appropriate scientific tools, in particular regarding the control and monitoring of the oxygen partial pressure (pO 2 ). Here we discuss several in-situ X-ray diffraction experiments performed to determine the phases present in the hypo-stoichiometric CeO 2-x region of the phase diagram and clearly demonstrate the need for controlling the pO 2 . (authors)

  20. Highly selective room temperature NO2 gas sensor based on rGO-ZnO composite

    Science.gov (United States)

    Jyoti, Kanaujiya, Neha; Varma, G. D.

    2018-05-01

    Blending metal oxide nanoparticles with graphene or its derivatives can greatly enhance gas sensing characteristics. In the present work, ZnO nanoparticles have been synthesized via reflux method. Thin films of reduced graphene oxide (rGO) and composite of rGO-ZnO have been fabricated by drop casting method for gas sensing application. The samples have been characterized by X-ray diffraction (XRD) and Field-emission scanning electron microscope (FESEM) for the structural and morphological studies respectively. Sensing measurements have been carried out for the composite film of rGO-ZnO for different concentrations of NO2 ranging from 4 to 100 ppm. Effect of increasing temperature on the sensing performance has also been studied and the rGO-ZnO composite sensor shows maximum percentage response at room temperature. The limit of detection (LOD) for rGO-ZnO composite sensor is 4ppm and it exhibits a high response of 48.4% for 40 ppm NO2 at room temperature. To check the selectivity of the composite sensor, sensor film has been exposed to 40 ppm different gases like CO, NH3, H2S and Cl2 at room temperature and the sensor respond negligibly to these gases. The present work suggests that rGO-ZnO composite material can be a better candidate for fabrication of highly selective room temperature NO2 gas sensor.