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Sample records for situ high pressure-temperature

  1. 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

  2. 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)

  3. 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.

  4. 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

  5. In-situ Diffraction Study of Magnetite at Simultaneous High Pressure and High Temperature Using Synchrotron Radiation

    Science.gov (United States)

    Wang, L.; Zhang, J.; Wang, S.; Chen, H.; Zhao, Y.

    2014-12-01

    Magnetite intertwined with the evolution of human civilizations, and remains so today. It is technologically and scientifically important by virtue of its unique magnetic and electrical properties. Magnetite is a common mineral found in a variety of geologic environments, and plays an important role in deciphering the oxygen evolution in the Earth's atmosphere and its deep interiors. The latter application asks for the knowledge of the thermal and elastic properties of magnetite at high pressures and temperatures, which is currently not available in literature. We have carried out a few in-situ diffraction experiments on magnetite using white synchrotron radiation at beamline X17B2 of National Synchrotron Light Source (NSLS). A DIA module in an 1100-ton press and WC anvils were employed for compression, and diffraction spectra were collected at simultaneous high pressures (P) and temperatures (T) (up to 9 GPa and 900 oC). Mixture of amorphous boron and epoxy resin was used as pressure medium, and NaCl as pressure marker. Temperature was recorded by W-Re thermocouples. Commercially purchased magnetite powder and a mixture of the said powder and NaCl (1:1) were used as starting material in separate experiments. Preliminary data analyses have yielded following observations: (1) Charge disordering seen at ambient pressure remains active in current experiments, especially at lower pressures (reversibility and degree of cation disordering depend on the starting material and/or experimental P-T path; and (4) cation disordering notably reduces the apparent bulk moduli of magnetite.

  6. Microwave Wire Interrogation Method Mapping Pressure under High Temperatures

    Directory of Open Access Journals (Sweden)

    Xiaoyong Chen

    2017-12-01

    Full Text Available It is widely accepted that wireless reading for in-situ mapping of pressure under high-temperature environments is the most feasible method, because it is not subject to frequent heterogeneous jointing failures and electrical conduction deteriorating, or even disappearing, under heat load. However, in this article, we successfully demonstrate an in-situ pressure sensor with wire interrogation for high-temperature applications. In this proof-of-concept study of the pressure sensor, we used a microwave resonator as a pressure-sensing component and a microwave transmission line as a pressure characteristic interrogation tunnel. In the sensor, the line and resonator are processed into a monolith, avoiding a heterogeneous jointing failure; further, microwave signal transmission does not depend on electrical conduction, and consequently, the sensor does not suffer from the heat load. We achieve pressure monitoring under 400 °C when employing the sensor simultaneously. Our sensor avoids restrictions that exist in wireless pressure interrogations, such as environmental noise and interference, signal leakage and security, low transfer efficiency, and so on.

  7. High pressure and high temperature EXAFS and diffraction study of AgI

    International Nuclear Information System (INIS)

    Yoshiasa, Akira; Arima, Hiroshi; Fukui, Hiroshi; Okube, Maki; Katayama, Yoshinori; Ohtaka, Osamu

    2009-01-01

    We have determined the precise P-T phase diagram of AgI by in-situ high-pressure high-temperature synchrotron experiments. X-ray diffraction and XAFS measurements were performed up to 6.0 GPa and 1100 K using a multi-anvil high-pressure device and synchrotron radiation from SPring-8. In the disordered rock-salt phase, Ag ions occupy both octahedral and tetrahedral sites and twenty percent of Ag ions occupy the tetrahedral site as a maximum value at 2 GPa. From the viewpoint of the local structure analyses, some sudden changes are recognized near broad phase transition point. Analysis of EXAFS Debye-Waller factor is useful because the force constant can be decided directly even at high pressure and high temperature. Pressure influences greatly the effective potential and anharmonicity decreases with increasing pressure. (author)

  8. Development of in situ Brillouin spectroscopy at high pressure and high temperature with synchrotron radiation and infrared laser heating system: Application to the Earth's deep interior

    Science.gov (United States)

    Murakami, Motohiko; Asahara, Yuki; Ohishi, Yasuo; Hirao, Naohisa; Hirose, Kei

    2009-05-01

    Seismic wave velocity profiles in the Earth provide one of the strongest constraints on structure, mineralogy and elastic properties of the Earth's deep interior. Accurate sound velocity data of deep Earth materials under relevant high-pressure and high-temperature conditions, therefore, are essential for interpretation of seismic data. Such information can be directly obtained from Brillouin scattering measurement. Here we describe an in situ Brillouin scattering system for measurements at high pressure and high temperature using a laser heated diamond anvil cell and synchrotron radiation for sample characterization. The system has been used with single-crystal and polycrystalline materials, and with glass and fluid phase. It provided high quality sound velocity and elastic data with X-ray diffraction data at high pressure and/or high temperature. Those combined techniques can potentially offer the essential information for resolving many remaining issues in mineral physics.

  9. In situ high-pressure measurement of crystal solubility by using neutron diffraction

    Science.gov (United States)

    Chen, Ji; Hu, Qiwei; Fang, Leiming; He, Duanwei; Chen, Xiping; Xie, Lei; Chen, Bo; Li, Xin; Ni, Xiaolin; Fan, Cong; Liang, Akun

    2018-05-01

    Crystal solubility is one of the most important thermo-physical properties and plays a key role in industrial applications, fundamental science, and geoscientific research. However, high-pressure in situ measurements of crystal solubility remain very challenging. Here, we present a method involving high-pressure neutron diffraction for making high-precision in situ measurements of crystal solubility as a function of pressure over a wide range of pressures. For these experiments, we designed a piston-cylinder cell with a large chamber volume for high-pressure neutron diffraction. The solution pressures are continuously monitored in situ based on the equation of state of the sample crystal. The solubility at a high pressure can be obtained by applying a Rietveld quantitative multiphase analysis. To evaluate the proposed method, we measured the high-pressure solubility of NaCl in water up to 610 MPa. At a low pressure, the results are consistent with the previous results measured ex situ. At a higher pressure, more reliable data could be provided by using an in situ high-pressure neutron diffraction method.

  10. 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.

  11. Structural stability of high entropy alloys under pressure and temperature

    DEFF Research Database (Denmark)

    Ahmad, Azkar S.; Su, Y.; Liu, S. Y.

    2017-01-01

    The stability of high-entropy alloys (HEAs) is a key issue before their selection for industrial applications. In this study, in-situ high-pressure and high-temperature synchrotron radiation X-ray diffraction experiments have been performed on three typical HEAs Ni20Co20Fe20Mn20Cr20, Hf25Nb25Zr25Ti...

  12. High-pressure, high-temperature magic angle spinning nuclear magnetic resonance devices and processes for making and using same

    Science.gov (United States)

    Hu, Jian Zhi; Hu, Mary Y.; Townsend, Mark R.; Lercher, Johannes A.; Peden, Charles H. F.

    2015-10-06

    Re-usable ceramic magic angle spinning (MAS) NMR rotors constructed of high-mechanic strength ceramics are detailed that include a sample compartment that maintains high pressures up to at least about 200 atmospheres (atm) and high temperatures up to about least about 300.degree. C. during operation. The rotor designs minimize pressure losses stemming from penetration over an extended period of time. The present invention makes possible a variety of in-situ high pressure, high temperature MAS NMR experiments not previously achieved in the prior art.

  13. Multipurpose high-pressure high-temperature diamond-anvil cell with a novel high-precision guiding system and a dual-mode pressurization device

    Science.gov (United States)

    Pippinger, Thomas; Miletich, Ronald; Burchard, Michael

    2011-09-01

    A novel diamond-anvil cell (DAC) design has been constructed and tested for in situ applications at high-pressure (HP) operations and has proved to be suitable even for HP sample environments at non-ambient temperature conditions. The innovative high-precision guiding mechanism, comparable to a dog clutch, consists of perpendicular planar sliding-plane elements and is integrated directly into the base body of the cylindrically shaped DAC. The combination of two force-generating devices, i.e., mechanical screws and an inflatable gas membrane, allows the user to choose independently between, and to apply individually, two different forcing mechanisms for pressure generation. Both mechanisms are basically independent of each other, but can also be operated simultaneously. The modularity of the DAC design allows for an easy exchange of functional core-element groups optimized not only for various analytical in situ methods but also for HP operation with or without high-temperature (HT) application. For HP-HT experiments a liquid cooling circuit inside the specific inner modular groups has been implemented to obtain a controlled and limited heat distribution within the outer DAC body.

  14. Evaluation of high temperature pressure sensors

    International Nuclear Information System (INIS)

    Choi, In-Mook; Woo, Sam-Yong; Kim, Yong-Kyu

    2011-01-01

    It is becoming more important to measure the pressure in high temperature environments in many industrial fields. However, there is no appropriate evaluation system and compensation method for high temperature pressure sensors since most pressure standards have been established at room temperature. In order to evaluate the high temperature pressure sensors used in harsh environments, such as high temperatures above 250 deg. C, a specialized system has been constructed and evaluated in this study. The pressure standard established at room temperature is connected to a high temperature pressure sensor through a chiller. The sensor can be evaluated in conditions of changing standard pressures at constant temperatures and of changing temperatures at constant pressures. According to the evaluation conditions, two compensation methods are proposed to eliminate deviation due to sensitivity changes and nonlinear behaviors except thermal hysteresis.

  15. The ReactorSTM: Atomically resolved scanning tunneling microscopy under high-pressure, high-temperature catalytic reaction conditions

    Energy Technology Data Exchange (ETDEWEB)

    Herbschleb, C. T.; Tuijn, P. C. van der; Roobol, S. B.; Navarro, V.; Bakker, J. W.; Liu, Q.; Stoltz, D.; Cañas-Ventura, M. E.; Verdoes, G.; Spronsen, M. A. van; Bergman, M.; Crama, L.; Taminiau, I.; Frenken, J. W. M., E-mail: frenken@physics.leidenuniv.nl [Huygens-Kamerlingh Onnes Laboratory, Leiden University, P.O. box 9504, 2300 RA Leiden (Netherlands); Ofitserov, A.; Baarle, G. J. C. van [Leiden Probe Microscopy B.V., J.H. Oortweg 21, 2333 CH Leiden (Netherlands)

    2014-08-15

    To enable atomic-scale observations of model catalysts under conditions approaching those used by the chemical industry, we have developed a second generation, high-pressure, high-temperature scanning tunneling microscope (STM): the ReactorSTM. It consists of a compact STM scanner, of which the tip extends into a 0.5 ml reactor flow-cell, that is housed in a ultra-high vacuum (UHV) system. The STM can be operated from UHV to 6 bars and from room temperature up to 600 K. A gas mixing and analysis system optimized for fast response times allows us to directly correlate the surface structure observed by STM with reactivity measurements from a mass spectrometer. The in situ STM experiments can be combined with ex situ UHV sample preparation and analysis techniques, including ion bombardment, thin film deposition, low-energy electron diffraction and x-ray photoelectron spectroscopy. The performance of the instrument is demonstrated by atomically resolved images of Au(111) and atom-row resolution on Pt(110), both under high-pressure and high-temperature conditions.

  16. Six-axis multi-anvil press for high-pressure, high-temperature neutron diffraction experiments

    Energy Technology Data Exchange (ETDEWEB)

    Sano-Furukawa, A., E-mail: sano.asami@jaea.go.jp; Hattori, T. [Quantum Beam Science Center, Japan Atomic Energy Agency, Ibaraki 319-1195 (Japan); J-PARC Center, Japan Atomic Energy Agency, Ibaraki 319-1195 (Japan); Arima, H. [Institute for Materials Research, Tohoku University, Sendai 980-8577 (Japan); Yamada, A. [The University of Shiga Prefecture, Shiga 522-8533 (Japan); Tabata, S.; Kondo, M.; Nakamura, A. [Sumitomo Heavy Industries Co., Ltd., Ehime 792-0001 (Japan); Kagi, H.; Yagi, T. [Geochemical Research Center, Graduate School of Science, The University of Tokyo, Tokyo 113-0033 (Japan)

    2014-11-15

    We developed a six-axis multi-anvil press, ATSUHIME, for high-pressure and high-temperature in situ time-of-flight neutron powder diffraction experiments. The press has six orthogonally oriented hydraulic rams that operate individually to compress a cubic sample assembly. Experiments indicate that the press can generate pressures up to 9.3 GPa and temperatures up to 2000 K using a 6-6-type cell assembly, with available sample volume of about 50 mm{sup 3}. Using a 6-8-type cell assembly, the available conditions expand to 16 GPa and 1273 K. Because the six-axis press has no guide blocks, there is sufficient space around the sample to use the aperture for diffraction and place an incident slit, radial collimators, and a neutron imaging camera close to the sample. Combination of the six-axis press and the collimation devices realized high-quality diffraction pattern with no contamination from the heater or the sample container surrounding the sample. This press constitutes a new tool for using neutron diffraction to study the structures of crystals and liquids under high pressures and temperatures.

  17. Application on electrochemistry measurement of high temperature high pressure condition in PWR nuclear power plants

    International Nuclear Information System (INIS)

    Li Yuchun; Xiao Zhongliang; Jiang Ya; Yu Xiaowei; Pang Feifei; Deng Fenfang; Gao Fan; Zhou Nianguang

    2011-01-01

    High temperature high pressure electrochemistry testing system was comprehensively analyzed in this paper, according to actual status for supervision in primary and secondary circuits of PWR nuclear power plants. Three research methods were reviewed and discussed for in-situ monitor system. By combination with ECP realtime measurement it was executed for evaluation and water chemistry optimization in nuclear power plants. It is pointed out that in-situ electrochemistry measurement has great potential application for water chemistry evaluation in PWR nuclear power plants. (authors)

  18. Elastic Wave Velocity Measurements on Mantle Peridotite at High Pressure and Temperature

    Science.gov (United States)

    Mistler, G. W.; Ishikawa, M.; Li, B.

    2002-12-01

    With the success of conducting ultrasonic measurements at high pressure and high temperature in large volume high pressure apparatus with in-situ measurement of the sample length by X-ray imaging, it is now possible to measure elastic wave velocities on aggregate samples with candidate compositions of the mantle to the conditions of the Earth's transition zone in the laboratory. These data can be directly compared with seismic data to distinguish the compositional models in debate. In this work, we carried out velocity measurements on natural peridotite KLB-1 at the conditions of the Earth's upper mantle. Fine powered sample of natural KLB-1 was used as starting material. Specimens for ultrasonic measurements were hot-pressed and equilibrated at various pressure and temperature conditions along geotherm up to the transition zone. The recovered samples were characterized with density measurement, X-ray diffraction and microprobe analysis. Bench top P and S wave velocities of KLB-1 sample sintered at 3-4 GPa and 1400 degree centigrade showed a very good agreement with the VRH average of pyrolite. High pressure and high temperature measurements was conducted up to 7 GPa and 800 degree centigrade using ultrasonic interferometric method in a DIA-type high pressure apparatus in conjunction with X-ray diffraction and X-ray imaging. The utilization of X-ray imaging technique provides direct measurements of sample lengths at high pressure and high temperature, ensuring a precise determination of velocities. The results of P and S wave velocities at high pressure and high temperature as well as their comparison with calculated pyrolite model will be presented.

  19. 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.

  20. 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.

  1. In Situ Observations of Thermoreversible Gelation and Phase Separation of Agarose and Methylcellulose Solutions under High Pressure.

    Science.gov (United States)

    Kometani, Noritsugu; Tanabe, Masahiro; Su, Lei; Yang, Kun; Nishinari, Katsuyoshi

    2015-06-04

    Thermoreversible sol-gel transitions of agarose and methylcellulose (MC) aqueous solutions on isobaric cooling or heating under high pressure up to 400 MPa have been investigated by in situ observations of optical transmittance and falling-ball experiments. For agarose, which undergoes the gelation on cooling, the application of pressure caused a gradual rise in the cloud-point temperature over the whole pressure range examined, which is almost consistent with the pressure dependence of gelling temperature estimated by falling-ball experiments, suggesting that agarose gel is stabilized by compression and that the gelation occurs nearly in parallel with phase separation under ambient and high-pressure conditions. For MC, which undergoes the gelation on heating, the cloud-point temperature showed a slight rise with an initial elevation of pressure up to ∼150 MPa, whereas it showed a marked depression above 200 MPa. In contrast, the gelling temperature of MC, which is nearly identical to the cloud-point temperature at ambient pressure, showed a monotonous rise with increasing pressure up to 350 MPa, which means that MC undergoes phase separation prior to gelation on heating under high pressure above 200 MPa. Similar results were obtained for the melting process of MC gel on cooling. The unique behavior of the sol-gel transition of MC under high pressure has been interpreted in terms of the destruction of hydrophobic hydration by compression.

  2. 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)

  3. Assessing the High Temperature, High Pressure Subsurface for Anaerobic Methane Oxidation

    Science.gov (United States)

    Harris, R. L.; Bartlett, D.; Byrnes, A. W.; Walsh, K. M.; Lau, C. Y. M.; Onstott, T. C.

    2017-12-01

    The anaerobic oxidation of methane (AOM) is an important sink in the global methane (CH4) budget. ANMEs are known to oxidize CH4 either independently or in consortia with bacteria, coupling the reduction of electron acceptors such as, SO42-, NO2-, NO3-, Mn4+, or Fe3+. To further constrain the contribution of AOM to the global CH4 budget, it is important to assess unexplored environments where AOM is thermodynamically possible such as the high pressure, high temperature deep biosphere. Provided plausible electron acceptor availability, increased temperature and pCH4 yield favorable Gibbs free energies for AOM reactions and the production of ATP (Fig. 1). To date, only sulfate-dependent AOM metabolism has been documented under high temperature conditions (50-72˚C), and AOM has not been assessed above 10.1 MPa. Given that ANMEs share close phylogenetic and metabolic heritage with methanogens and that the most heat-tolerant microorganism known is a barophilic methanogen, there possibly exist thermophilic ANMEs. Here we describe preliminary results from high pressure, high temperature stable isotope tracer incubation experiments on deep biosphere samples. Deep sub-seafloor sediments collected by IODP 370 from the Nankai Trough (257 - 865 m below seafloor) and deep fracture fluid from South Africa (1339 m below land surface) were incubated anaerobically in hydrostatic pressure vessels at 40 MPa in simulated in situ temperatures (40˚ - 80˚C). Sediments and fracture fluid were incubated in sulfate-free artificial seawater, a 2:98 13CH4:N2 headspace, and treated with one of the potential electron acceptors listed above in addition to kill and endogenous activity (i.e. no added electron acceptor) controls. Stable isotope analysis of dissolved inorganic carbon (DIC) suggests that AOM occurred within 60 days of incubation for all investigated electron acceptors and temperatures except 50˚C. Sulfate-dependent AOM rates are consistent with those previously reported in the

  4. 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...

  5. Phase diagram and equation of state of TiH2 at high pressures and high temperatures

    International Nuclear Information System (INIS)

    Endo, Naruki; Saitoh, Hiroyuki; Machida, Akihiko; Katayama, Yoshinori; Aoki, Katsutoshi

    2013-01-01

    Highlights: ► We determined the phase diagram of TiH 2 at high pressures and high temperatures. ► Compression induced stain inhibited the phase transition from the bct to fcc phase. ► The phase boundary was appropriately determined using a sample with heat treatment. ► The high temperature Birch–Murnaghan equation of state of fcc TiH 2 was firstly determined. - Abstract: We determined the phase diagram and the equation of state (EoS) of TiH 2 at high pressures up to 8.7 GPa and high temperatures up to 600 °C by in situ synchrotron radiation X-ray diffraction measurements. Compression induced strain inhibited the phase transition from the low-temperature bct phase to the high-temperature fcc phase, making the phase diagram difficult to determine. However, heating around 600 °C relieved the strain, and the phase boundary between the bct and fcc phases was elucidated. The phase transition temperature at ambient pressure increased from around room temperature to 200 °C at 8.7 GPa. The high temperature Birch–Murnaghan EoS was determined for the fcc phase. With the pressure derivative of the bulk modulus K′ 0 = 4.0, the following parameters were obtained: ambient bulk modulus K 0 = 97.7 ± 0.2 GPa, ambient unit cell of the fcc phase V 0 = 88.57 ± 0.02 Å 3 , temperature derivative of the bulk modulus at constant pressure (∂K/∂T) P = −0.01 ± 0.02, and volumetric thermal expansivity α = a + bT with a = 2.62 ± 1.4 × 10 −5 and b = 5.5 ± 4.5 × 10 −8 . K 0 of fcc TiH 2 was close to those for pure Ti and bct TiH 2 reported in previous studies.

  6. 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

  7. In situ structural analysis of calcium aluminosilicate glasses under high pressure.

    Science.gov (United States)

    Muniz, R F; de Ligny, D; Martinet, C; Sandrini, M; Medina, A N; Rohling, J H; Baesso, M L; Lima, S M; Andrade, L H C; Guyot, Y

    2016-08-10

    In situ micro-Raman spectroscopy was used to investigate the structural evolution of OH(-)-free calcium aluminosilicate glasses, under high pressure and at room temperature. Evaluation was made of the role of the SiO2 concentration in percalcic join systems, for Al/(Al  +  Si) in the approximate range from 0.9 to 0.2. Under high pressure, the intensity of the main band related to the bending mode of bridging oxygen ([Formula: see text][T-O-T], where T  =  Si or Al) decreased gradually, suggesting that the bonds were severely altered or even destroyed. In Si-rich glasses, compression induced a transformation of Q (n) species to Q (n-1). In the case of Al-rich glass, the Al in the smallest Q (n) units evolved from tetrahedral to higher-coordinated Al (([5])Al and ([6])Al). Permanent structural changes were observed in samples recovered from the highest pressure of around 15 GPa and, particularly for Si-rich samples, the recovered structure showed an increase of three-membered rings in the Si/Al tetrahedral network.

  8. High pressure study of high-temperature superconductors

    Energy Technology Data Exchange (ETDEWEB)

    Souliou, Sofia-Michaela

    2014-09-29

    The current thesis studies experimentally the effect of high external pressure on high-T{sub c} superconductors. The structure and lattice dynamics of several members of the high-T{sub c} cuprate and Fe-based superconductors families were investigated by means of Raman spectroscopy and X-ray diffraction under well-controlled, hydrostatic high pressure and low temperature conditions. The lattice dynamics of the high-T{sub c} superconductor YBa{sub 2}Cu{sub 3}O{sub 6+x} have been investigated systematically by Raman spectroscopy as a function of doping (x = 0.95, 0.75, 0.60, 0.55, and 0.45) and external pressure. Under ambient pressure conditions, in addition to the Raman modes expected from group theory, we observe new Raman active phonons upon cooling the underdoped samples, at temperatures well above the superconducting transition temperature. The doping dependence and the onset temperatures of the new Raman features suggest that they are associated with the incommensurate charge density wave (CDW) state recently discovered in underdoped cuprates using synchrotron X-ray scattering techniques. Under high pressure conditions (from 2 to 12 GPa), our Raman measurements on highly ordered underdoped YBa{sub 2}Cu{sub 3}O{sub 6.55} samples do not show any of the new Raman phonons seen at ambient pressure. High pressure and low temperature Raman measurements have been performed on the underdoped superconductor YBa{sub 2}Cu{sub 4}O{sub 8}. A clear renormalization of some of the Raman phonons is seen below T{sub c} as a result of the changes in the phonon self-energy upon the opening of the superconducting gap, with the most prominent one being that of the B{sub 1g}-like buckling phonon mode. The amplitude of this renormalization strongly increases with pressure, resembling the effect of hole doping in YBa{sub 2}Cu{sub 3}O{sub 6+x}. At ∝ 10 GPa, the system undergoes a reversible pressure-induced structural phase transition to a non-centrosymmmetric structure (space group

  9. High pressure study of high-temperature superconductors

    International Nuclear Information System (INIS)

    Souliou, Sofia-Michaela

    2014-01-01

    The current thesis studies experimentally the effect of high external pressure on high-T c superconductors. The structure and lattice dynamics of several members of the high-T c cuprate and Fe-based superconductors families were investigated by means of Raman spectroscopy and X-ray diffraction under well-controlled, hydrostatic high pressure and low temperature conditions. The lattice dynamics of the high-T c superconductor YBa 2 Cu 3 O 6+x have been investigated systematically by Raman spectroscopy as a function of doping (x = 0.95, 0.75, 0.60, 0.55, and 0.45) and external pressure. Under ambient pressure conditions, in addition to the Raman modes expected from group theory, we observe new Raman active phonons upon cooling the underdoped samples, at temperatures well above the superconducting transition temperature. The doping dependence and the onset temperatures of the new Raman features suggest that they are associated with the incommensurate charge density wave (CDW) state recently discovered in underdoped cuprates using synchrotron X-ray scattering techniques. Under high pressure conditions (from 2 to 12 GPa), our Raman measurements on highly ordered underdoped YBa 2 Cu 3 O 6.55 samples do not show any of the new Raman phonons seen at ambient pressure. High pressure and low temperature Raman measurements have been performed on the underdoped superconductor YBa 2 Cu 4 O 8 . A clear renormalization of some of the Raman phonons is seen below T c as a result of the changes in the phonon self-energy upon the opening of the superconducting gap, with the most prominent one being that of the B 1g -like buckling phonon mode. The amplitude of this renormalization strongly increases with pressure, resembling the effect of hole doping in YBa 2 Cu 3 O 6+x . At ∝ 10 GPa, the system undergoes a reversible pressure-induced structural phase transition to a non-centrosymmmetric structure (space group Imm2). The structural transition is clearly reflected in the high pressure

  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. Temperature uniformity mapping in a high pressure high temperature reactor using a temperature sensitive indicator

    NARCIS (Netherlands)

    Grauwet, T.; Plancken, van der I.; Vervoort, L.; Matser, A.M.; Hendrickx, M.; Loey, van A.

    2011-01-01

    Recently, the first prototype ovomucoid-based pressure–temperature–time indicator (pTTI) for high pressure high temperature (HPHT) processing was described. However, for temperature uniformity mapping of high pressure (HP) vessels under HPHT sterilization conditions, this prototype needs to be

  12. 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

  13. Pressure pressure-balanced pH sensing system for high temperature and high pressure water

    International Nuclear Information System (INIS)

    Tachibana, Koji

    1995-01-01

    As for the pH measurement system for high temperature, high pressure water, there have been the circumstances that first the reference electrodes for monitoring corrosion potential were developed, and subsequently, it was developed for the purpose of maintaining the soundness of metallic materials in high temperature, high pressure water in nuclear power generation. In the process of developing the reference electrodes for high temperature water, it was clarified that the occurrence of stress corrosion cracking in BWRs is closely related to the corrosion potential determined by dissolved oxygen concentration. As the types of pH electrodes, there are metal-hydrogen electrodes, glass electrodes, ZrO 2 diaphragm electrodes and TiO 2 semiconductor electrodes. The principle of pH measurement using ZrO 2 diaphragms is explained. The pH measuring system is composed of YSZ element, pressure-balanced type external reference electrode, pressure balancer and compressed air vessel. The stability and pH response of YSZ elements are reported. (K.I.)

  14. Passive Resistor Temperature Compensation for a High-Temperature Piezoresistive Pressure Sensor.

    Science.gov (United States)

    Yao, Zong; Liang, Ting; Jia, Pinggang; Hong, Yingping; Qi, Lei; Lei, Cheng; Zhang, Bin; Li, Wangwang; Zhang, Diya; Xiong, Jijun

    2016-07-22

    The main limitation of high-temperature piezoresistive pressure sensors is the variation of output voltage with operating temperature, which seriously reduces their measurement accuracy. This paper presents a passive resistor temperature compensation technique whose parameters are calculated using differential equations. Unlike traditional experiential arithmetic, the differential equations are independent of the parameter deviation among the piezoresistors of the microelectromechanical pressure sensor and the residual stress caused by the fabrication process or a mismatch in the thermal expansion coefficients. The differential equations are solved using calibration data from uncompensated high-temperature piezoresistive pressure sensors. Tests conducted on the calibrated equipment at various temperatures and pressures show that the passive resistor temperature compensation produces a remarkable effect. Additionally, a high-temperature signal-conditioning circuit is used to improve the output sensitivity of the sensor, which can be reduced by the temperature compensation. Compared to traditional experiential arithmetic, the proposed passive resistor temperature compensation technique exhibits less temperature drift and is expected to be highly applicable for pressure measurements in harsh environments with large temperature variations.

  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. High-pressure high-temperature phase diagram of organic crystal paracetamol

    Science.gov (United States)

    Smith, Spencer J.; Montgomery, Jeffrey M.; Vohra, Yogesh K.

    2016-01-01

    High-pressure high-temperature (HPHT) Raman spectroscopy studies have been performed on the organic crystal paracetamol in a diamond anvil cell utilizing boron-doped heating diamond anvil. Isobaric measurements were conducted at pressures up to 8.5 GPa and temperature up to 520 K in five different experiments. Solid state phase transitions from monoclinic Form I  →  orthorhombic Form II were observed at various pressures and temperatures as well as transitions from Form II  →  unknown Form IV. The melting temperature for paracetamol was observed to increase with increasing pressures to 8.5 GPa. This new data is combined with previous ambient temperature high-pressure Raman and x-ray diffraction data to create the first HPHT phase diagram of paracetamol.

  17. High-pressure high-temperature phase diagram of organic crystal paracetamol

    International Nuclear Information System (INIS)

    Smith, Spencer J; Montgomery, Jeffrey M; Vohra, Yogesh K

    2016-01-01

    High-pressure high-temperature (HPHT) Raman spectroscopy studies have been performed on the organic crystal paracetamol in a diamond anvil cell utilizing boron-doped heating diamond anvil. Isobaric measurements were conducted at pressures up to 8.5 GPa and temperature up to 520 K in five different experiments. Solid state phase transitions from monoclinic Form I  →  orthorhombic Form II were observed at various pressures and temperatures as well as transitions from Form II  →  unknown Form IV. The melting temperature for paracetamol was observed to increase with increasing pressures to 8.5 GPa. This new data is combined with previous ambient temperature high-pressure Raman and x-ray diffraction data to create the first HPHT phase diagram of paracetamol. (paper)

  18. A novel SOI pressure sensor for high temperature application

    International Nuclear Information System (INIS)

    Li Sainan; Liang Ting; Wang Wei; Hong Yingping; Zheng Tingli; Xiong Jijun

    2015-01-01

    The silicon on insulator (SOI) high temperature pressure sensor is a novel pressure sensor with high-performance and high-quality. A structure of a SOI high-temperature pressure sensor is presented in this paper. The key factors including doping concentration and power are analyzed. The process of the sensor is designed with the critical process parameters set appropriately. The test result at room temperature and high temperature shows that nonlinear error below is 0.1%, and hysteresis is less than 0.5%. High temperature measuring results show that the sensor can be used for from room temperature to 350 °C in harsh environments. It offers a reference for the development of high temperature piezoresistive pressure sensors. (semiconductor devices)

  19. Analysis of the structural stability of the smectite submitted to high pressures and temperatures

    International Nuclear Information System (INIS)

    Alabarse, Frederico Gil

    2009-10-01

    The thermal stability of bentonite is of particular interest for containment barrier in nuclear waste disposal facilities. However, very little is known about the stability of smectite (principal component of bentonite) under high-pressure and high-temperature conditions (HPHT). The objective of this work was to investigate the stability of the smectite structure under HP-HT conditions. The HP-HT experiments were performed on toroidal chambers (TC) with pressure up 7.7 GPa and temperatures of 1000 deg C. The samples were characterized by X-ray diffraction after the HP-HT processing. Furthermore, one sample from the original material was analyzed using Fourier transformed infra-red (FTIR) in situ measurements on a diamond anvil cell (DAC) in experiments up to 12 GPa. The original sample of bentonite, calcium dioctahedral montmorillonite with small fraction of quartz, was characterized by FTIR, XRD, X-ray fluorescence (XRF), scanning electron microscopy (SEM), surface area, thermogravimetric analysis (TGA) and differential thermal analysis (DTA). In the experiment performed using the DAC up to 12 GPa, the FTIR in situ measurements analysis showed that the smectite structure is stable with a reversible deformation in the Si-O bond and that the smectite did not loose water. Experiments performed in TC at 7.7 GPa of pressure and 250 deg C of temperature, during 3.5 h showed, after analysis by XRD and FTIR, that the smectite structure is stable and did not loose water. Experiments performed in TC at 7.7 GPa of pressure and 1000 deg C of temperature, during 3.5 h showed, after analysis by XRD and SEM, the transformation of bentonite to the mineral assemblage: Coesite, Quartz, Kyanite and Pyrope. (author)

  20. High Pressure Scanning Tunneling Microscopy Studies of AdsorbateStructure and Mobility during Catalytic Reactions: Novel Design of anUltra High Pressure, High Temperature Scanning Tunneling MicroscopeSystem for Probing Catalytic Conversions

    Energy Technology Data Exchange (ETDEWEB)

    Tang, David Chi-Wai [Univ. of California, Berkeley, CA (United States)

    2005-05-16

    The aim of the work presented therein is to take advantage of scanning tunneling microscope’s (STM) capability for operation under a variety of environments under real time and at atomic resolution to monitor adsorbate structures and mobility under high pressures, as well as to design a new generation of STM systems that allow imaging in situ at both higher pressures (35 atm) and temperatures (350 °C).

  1. Viscosity of komatiite liquid at high pressure and temperature

    Science.gov (United States)

    O Dwyer, L.; Lesher, C. E.; Wang, Y.

    2006-12-01

    The viscosities of komatiite liquids at high pressures and temperatures are being investigated by the in-situ falling sphere technique, using the T-25 multianvil apparatus at the GSECARS 13 ID-D beamline at the Advanced Photon Source, ANL. The refractory and fluid nature of komatiite and other ultramafic liquids relevant to the Earth's deep interior, presents unique challenges for this approach. To reach superliquidus temperatures we use a double reservoir configuration, where marker spheres are placed at the top of both a main melt reservoir and an overlying reservoir containing a more refractory composition. Using this approach, we have successfully measured the viscosity of a komatiite from Gorgona Island (GOR-94-29; MgO - 17.8 wt.%; NBO/T = 1.6) up to 6 GPa and 1900 K. Under isothermal conditions, viscosity increases with pressure, consistent with the depolymerized nature of the komatiite. At 1900 K, viscosity increases from 1.5 (+- 0.3) Pa s at 3.5 GPa to 3.4 (+- 0.3) Pa s at 6 GPa, corresponding to an activation volume of 2.2 cm3/mol. At high pressures, the viscosities of Gorgona Island komatiite melt are an order of magnitude higher than those measured by Liebske et al. (2005, EPSL, v. 240) for peridotite melt (MgO 37.1 wt.%; NBO/T = 2.5), and similar in magnitude to molten diopside (NBO/T = 2) (Reid et al. 2003, PEPI, v. 139). The positive pressure dependence is consistent with the reduction in interatomic space diminishing the free volume of the liquid as it is compressed. Above 6 GPa the free volume reduction may become less important with the production of high-coordinated network formers, as attributed to the reversal of the pressure dependence of viscosity for peridotite melt at ~8.5 GPa and diopside melt at ~10 GPa. Experiments at higher pressures are underway to determine if a similar viscosity maximum occurs for komatiite melt and whether its pressure is greater than 10 GPa, as suggested by the data for peridotite and diopside melts.

  2. High-pressure high-temperature experiments: Windows to the Universe

    International Nuclear Information System (INIS)

    Santaria-Perez, D.

    2011-01-01

    From Earth compositional arguments suggested by indirect methods, such as the propagation of seismic waves, is possible to generate in the laboratory pressure and temperature conditions similar to those of the Earth or other planet interiors and to study how these conditions affect to a certain metal or mineral. These experiments are, therefore, windows to the Universe. The aim of this chapter is to illustrate the huge power of the experimental high-pressure high-temperature techniques and give a global overview of their application to different geophysical fields. Finally, we will introduce the MALTA Consolider Team, which gather most of the Spanish high-pressure community, and present their available high-pressure facilities. (Author) 28 refs.

  3. Laser-Machined Microcavities for Simultaneous Measurement of High-Temperature and High-Pressure

    Directory of Open Access Journals (Sweden)

    Zengling Ran

    2014-08-01

    Full Text Available Laser-machined microcavities for simultaneous measurement of high-temperature and high-pressure are demonstrated. These two cascaded microcavities are an air cavity and a composite cavity including a section of fiber and an air cavity. They are both placed into a pressure chamber inside a furnace to perform simultaneous pressure and high-temperature tests. The thermal and pressure coefficients of the short air cavity are ~0.0779 nm/°C and ~1.14 nm/MPa, respectively. The thermal and pressure coefficients of the composite cavity are ~32.3 nm/°C and ~24.4 nm/MPa, respectively. The sensor could be used to separate temperature and pressure due to their different thermal and pressure coefficients. The excellent feature of such a sensor head is that it can withstand high temperatures of up to 400 °C and achieve precise measurement of high-pressure under high temperature conditions.

  4. Laser-machined microcavities for simultaneous measurement of high-temperature and high-pressure.

    Science.gov (United States)

    Ran, Zengling; Liu, Shan; Liu, Qin; Huang, Ya; Bao, Haihong; Wang, Yanjun; Luo, Shucheng; Yang, Huiqin; Rao, Yunjiang

    2014-08-07

    Laser-machined microcavities for simultaneous measurement of high-temperature and high-pressure are demonstrated. These two cascaded microcavities are an air cavity and a composite cavity including a section of fiber and an air cavity. They are both placed into a pressure chamber inside a furnace to perform simultaneous pressure and high-temperature tests. The thermal and pressure coefficients of the short air cavity are ~0.0779 nm/°C and ~1.14 nm/MPa, respectively. The thermal and pressure coefficients of the composite cavity are ~32.3 nm/°C and ~24.4 nm/MPa, respectively. The sensor could be used to separate temperature and pressure due to their different thermal and pressure coefficients. The excellent feature of such a sensor head is that it can withstand high temperatures of up to 400 °C and achieve precise measurement of high-pressure under high temperature conditions.

  5. High-pressure-high-temperature treatment of natural diamonds

    CERN Document Server

    Royen, J V

    2002-01-01

    The results are reported of high-pressure-high-temperature (HPHT) treatment experiments on natural diamonds of different origins and with different impurity contents. The diamonds are annealed in a temperature range up to 2000 sup o C at stabilizing pressures up to 7 GPa. The evolution is studied of different defects in the diamond crystal lattice. The influence of substitutional nitrogen atoms, plastic deformation and the combination of these is discussed. Diamonds are characterized at room and liquid nitrogen temperature using UV-visible spectrophotometry, Fourier transform infrared spectrophotometry and photoluminescence spectrometry. The economic implications of diamond HPHT treatments are discussed.

  6. 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.

  7. In situ study starch gelatinization under ultra-high hydrostatic pressure using synchrotron SAXS

    KAUST Repository

    Yang, Zhi

    2015-12-13

    The gelatinization of waxy (very low amylose) corn and potato starches by high hydrostatic pressure (HHP) (up to ∼1 GPa) was investigated in situ using synchrotron small-angle X-ray scattering (SAXS) on samples held in a diamond anvil cell (DAC). The starch pastes, made by mixing starch and water in a 1:1 ratio (by weight), were pressurized and measured at room temperature. During HHP, both SAXS peak areas (corresponding to the lamellar phase) of waxy corn and potato starches decreased suggesting the starch gelatinization increases with increasing pressure. As pressure increased, lamellar peak broadened and the power law exponent increased in low q region. 1D linear correlation function was further employed to analyse SAXS data. For both waxy potato and waxy corn starches, the long period length and the average thickness of amorphous layers decreased when the pressure increased. While for both of waxy starches, the thickness of the crystalline layer first increased, then decreased when the pressure increased. The former is probably due to the out-phasing of starch molecules, and the latter is due to the water penetrating into the crystalline region during gelatinization and to pressure induced compression.

  8. High temperature and high pressure equation of state of gold

    International Nuclear Information System (INIS)

    Matsui, Masanori

    2010-01-01

    High-temperature and high-pressure equation of state (EOS) of Au has been developed using measured data from shock compression up to 240 GPa, volume thermal expansion between 100 and 1300 K and 0 GPa, and temperature dependence of bulk modulus at 0 GPa from ultrasonic measurements. The lattice thermal pressures at high temperatures have been estimated based on the Mie-Grueneisen-Debye type treatment with the Vinet isothermal EOS. The contribution of electronic thermal pressure at high temperatures, which is relatively insignificant for Au, has also been included here. The optimized EOS parameters are K' 0T = 6.0 and q = 1.6 with fixed K 0T = 167 GPa, γ 0 = 2.97, and Θ 0 = 170 K from previous investigations. We propose the present EOS to be used as a reliable pressure standard for static experiments up to 3000K and 300 GPa.

  9. In situ study at high pressure and temperature of the environment of water in hydrous Na and Ca aluminosilicate melts and coexisting aqueous fluids

    Science.gov (United States)

    Le Losq, Charles; Dalou, Célia; Mysen, Bjorn O.

    2017-07-01

    The bonding and speciation of water dissolved in Na silicate and Na and Ca aluminosilicate melts were inferred from in situ Raman spectroscopy of the samples, in hydrothermal diamond anvil cells, while at crustal temperature and pressure conditions. Raman data were also acquired on Na silicate and Na and Ca aluminosilicate glasses, quenched from hydrous melts equilibrated at high temperature and pressure in a piston cylinder apparatus. In the hydrous melts, temperature strongly influences O-H stretching ν(O-H) signals, reflecting its control on the bonding of protons between different molecular complexes. Pressure and melt composition effects are much smaller and difficult to discriminate with the present data. However, the chemical composition of the melt + fluid system influences the differences between the ν(O-H) signals from the melts and the fluids and, hence, between their hydrogen partition functions. Quenching modifies the O-H stretching signals: strong hydrogen bonds form in the glasses below the glass transition temperature Tg, and this phenomenon depends on glass composition. Therefore, glasses do not necessarily record the O-H stretching signal shape in melts near Tg. The melt hydrogen partition function thus cannot be assessed with certainty using O-H stretching vibration data from glasses. From the present results, the ratio of the hydrogen partition functions of hydrous silicate melts and aqueous fluids mostly depends on temperature and the bulk melt + fluid system chemical composition. This implies that the fractionation of hydrogen isotopes between magmas and aqueous fluids in water-saturated magmatic systems with differences in temperature and bulk chemical composition will be different.

  10. In Situ Raman Study of Liquid Water at High Pressure.

    Science.gov (United States)

    Romanenko, Alexandr V; Rashchenko, Sergey V; Goryainov, Sergey V; Likhacheva, Anna Yu; Korsakov, Andrey V

    2018-06-01

    A pressure shift of Raman band of liquid water (H 2 O) may be an important tool for measuring residual pressures in mineral inclusions, in situ barometry in high-pressure cells, and as an indicator of pressure-induced structural transitions in H 2 O. However, there was no consensus as to how the broad and asymmetric water Raman band should be quantitatively described, which has led to fundamental inconsistencies between reported data. In order to overcome this issue, we measured Raman spectra of H 2 O in situ up to 1.2 GPa using a diamond anvil cell, and use them to test different approaches proposed for the description of the water Raman band. We found that the most physically meaningful description of water Raman band is the decomposition into a linear background and three Gaussian components, associated with differently H-bonded H 2 O molecules. Two of these components demonstrate a pronounced anomaly in pressure shift near 0.4 GPa, supporting ideas of structural transition in H 2 O at this pressure. The most convenient approach for pressure calibration is the use of "a linear background + one Gaussian" decomposition (the pressure can be measured using the formula P (GPa) = -0.0317(3)·Δν G (cm -1 ), where Δν G represents the difference between the position of water Raman band, fitted as a single Gaussian, in measured spectrum and spectrum at ambient pressure).

  11. High-temperature and high-pressure cubic zirconia anvil cell for Raman spectroscopy.

    Science.gov (United States)

    Chen, Jinyang; Zheng, Haifei; Xiao, Wansheng; Zeng, Yishan

    2003-10-01

    A simple and inexpensive cubic zirconia anvil cell has been developed for the performance of in situ Raman spectroscopy up to the conditions of 500 degrees C and 30 kbar pressure. The design and construction of this cell are fully described, as well as its applications for Raman spectroscopy. Molybdenum heater wires wrapped around ceramic tubes encircling two cubic zirconia anvils are used to heat samples, and the temperatures are measured and controlled by a Pt-PtRh thermocouple adhered near the sample chamber and an intelligent digital control apparatus. With this cell, Raman spectroscopic measurements have been satisfactorily performed on water at 6000 bar pressure to 455 degrees C and on ice of room temperature to 24 kbar, in which the determinations of pressures make use of changes of the A1 Raman modes of quartz and the shift of the sharpline (R-line) luminescence of ruby, respectively.

  12. Decomposition of silicon carbide at high pressures and temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Daviau, Kierstin; Lee, Kanani K. M.

    2017-11-01

    We measure the onset of decomposition of silicon carbide, SiC, to silicon and carbon (e.g., diamond) at high pressures and high temperatures in a laser-heated diamond-anvil cell. We identify decomposition through x-ray diffraction and multiwavelength imaging radiometry coupled with electron microscopy analyses on quenched samples. We find that B3 SiC (also known as 3C or zinc blende SiC) decomposes at high pressures and high temperatures, following a phase boundary with a negative slope. The high-pressure decomposition temperatures measured are considerably lower than those at ambient, with our measurements indicating that SiC begins to decompose at ~ 2000 K at 60 GPa as compared to ~ 2800 K at ambient pressure. Once B3 SiC transitions to the high-pressure B1 (rocksalt) structure, we no longer observe decomposition, despite heating to temperatures in excess of ~ 3200 K. The temperature of decomposition and the nature of the decomposition phase boundary appear to be strongly influenced by the pressure-induced phase transitions to higher-density structures in SiC, silicon, and carbon. The decomposition of SiC at high pressure and temperature has implications for the stability of naturally forming moissanite on Earth and in carbon-rich exoplanets.

  13. 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

  14. Method transfer from high-pressure liquid chromatography to ultra-high-pressure liquid chromatography. II. Temperature and pressure effects.

    Science.gov (United States)

    Åsberg, Dennis; Samuelsson, Jörgen; Leśko, Marek; Cavazzini, Alberto; Kaczmarski, Krzysztof; Fornstedt, Torgny

    2015-07-03

    The importance of the generated temperature and pressure gradients in ultra-high-pressure liquid chromatography (UHPLC) are investigated and compared to high-pressure liquid chromatography (HPLC). The drug Omeprazole, together with three other model compounds (with different chemical characteristics, namely uncharged, positively and negatively charged) were used. Calculations of the complete temperature profile in the column at UHPLC conditions showed, in our experiments, a temperature difference between the inlet and outlet of 16 °C and a difference of 2 °C between the column center and the wall. Through van't Hoff plots, this information was used to single out the decrease in retention factor (k) solely due to the temperature gradient. The uncharged solute was least affected by temperature with a decrease in k of about 5% while for charged solutes the effect was more pronounced, with k decreases up to 14%. A pressure increase of 500 bar gave roughly 5% increase in k for the uncharged solute, while omeprazole and the other two charged solutes gave about 25, 20 and 15% increases in k, respectively. The stochastic model of chromatography was applied to estimate the dependence of the average number of adsorption/desorption events (n) and the average time spent by a molecule in the stationary phase (τs) on temperature and pressure on peak shape for the tailing, basic solute. Increasing the temperature yielded an increase in n and decrease in τs which resulted in less skew at high temperatures. With increasing pressure, the stochastic modeling gave interesting results for the basic solute showing that the skew of the peak increased with pressure. The conclusion is that pressure effects are more pronounced for both retention and peak shape than the temperature effects for the polar or charged compounds in our study. Copyright © 2015 Elsevier B.V. All rights reserved.

  15. High-Pressure Design of Advanced BN-Based Materials

    Directory of Open Access Journals (Sweden)

    Oleksandr O. Kurakevych

    2016-10-01

    Full Text Available The aim of the present review is to highlight the state of the art in high-pressure design of new advanced materials based on boron nitride. Recent experimental achievements on the governing phase transformation, nanostructuring and chemical synthesis in the systems containing boron nitride at high pressures and high temperatures are presented. All these developments allowed discovering new materials, e.g., ultrahard nanocrystalline cubic boron nitride (nano-cBN with hardness comparable to diamond, and superhard boron subnitride B13N2. Thermodynamic and kinetic aspects of high-pressure synthesis are described based on the data obtained by in situ and ex situ methods. Mechanical and thermal properties (hardness, thermoelastic equations of state, etc. are discussed. New synthetic perspectives, combining both soft chemistry and extreme pressure–temperature conditions are considered.

  16. High-Pressure High-Temperature Phase Diagram of the Organic Crystal Paracetamol

    Science.gov (United States)

    Smith, Spencer; Montgomery, Jeffrey; Vohra, Yogesh

    High-pressure high-temperature (HPHT) Raman spectroscopy studies have been performed on the organic crystal paracetamol in a diamond anvil cell utilizing boron-doped diamond as heating anvil. The HPHT data obtained from boron-doped diamond heater is cross-checked with data obtained using a standard block heater diamond anvil cell. Isobaric measurements were conducted at pressures up to 8.5 GPa and temperature up to 520 K in a number of different experiments. Solid state phase transitions from monoclinic Form I --> orthorhombic Form II were observed at various pressures and temperatures as well as transitions from Form II --> unknown Form IV. The melting temperature for paracetamol was observed to increase with increasing pressures to 8.5 GPa. Our previous angle dispersive x-ray diffraction studies at the Advanced Photon Source has confirmed the existence of two unknown crystal structures Form IV and Form V of paracetamol at high pressure and ambient temperature. The phase transformation from Form II to Form IV occurs at ~8.5 GPa and from Form IV to Form V occurs at ~11 GPa at ambient temperature. Our new data is combined with the previous ambient temperature high-pressure Raman and X- ray diffraction data to create the first HPHT phase diagram of paracetamol. Doe-NNSA Carnegie DOE Alliance Center (CDAC) under Grant Number DE-NA0002006.

  17. 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

  18. Saturation curve of SiO2 component in rutile-type GeO2: A recoverable high-temperature pressure standard from 3 GPa to 10 GPa

    International Nuclear Information System (INIS)

    Leinenweber, Kurt; Gullikson, Amber L.; Stoyanov, Emil; Malik, Abds-Sami

    2015-01-01

    The accuracy and precision of pressure measurements and the pursuit of reliable and readily available pressure scales at simultaneous high temperatures and pressures are still topics in development in high pressure research despite many years of work. In situ pressure scales based on x-ray diffraction are widely used but require x-ray access, which is lacking outside of x-ray beam lines. Other methods such as fixed points require several experiments to bracket a pressure calibration point. In this study, a recoverable high-temperature pressure gauge for pressures ranging from 3 GPa to 10 GPa is presented. The gauge is based on the pressure-dependent solubility of an SiO 2 component in the rutile-structured phase of GeO 2 (argutite), and is valid when the argutite solid solution coexists with coesite. The solid solution varies strongly in composition, mainly in pressure but also somewhat in temperature, and the compositional variations are easily detected by x-ray diffraction of the recovered products because of significant changes in the lattice parameters. The solid solution is measured here on two isotherms, one at 1200 °C and the other at 1500 °C, and is developed as a pressure gauge by calibrating it against three fixed points for each temperature and against the lattice parameter of MgO measured in situ at a total of three additional points. A somewhat detailed thermodynamic analysis is then presented that allows the pressure gauge to be used at other temperatures. This provides a way to accurately and reproducibly evaluate the pressure in high pressure experiments and applications in this pressure-temperature range, and could potentially be used as a benchmark to compare various other pressure scales under high temperature conditions. - Graphical abstract: The saturation curve of SiO 2 in TiO 2 shows a strong pressure dependence and a strong dependence of unit cell volume on composition. This provides an opportunity to use this saturation curve as a

  19. Hardness of high-pressure high-temperature treated single-walled carbon nanotubes

    International Nuclear Information System (INIS)

    Kawasaki, S.; Nojima, Y.; Yokomae, T.; Okino, F.; Touhara, H.

    2007-01-01

    We have performed high-pressure high-temperature (HPHT) treatments of high quality single-walled carbon nanotubes (SWCNTs) over a wide pressure-temperature range up to 13 GPa-873 K and have investigated the hardness of the HPHT-treated SWCNTs using a nanoindentation technique. It was found that the hardness of the SWCNTs treated at pressures greater than 11 GPa and at temperatures higher than 773 K is about 10 times greater than that of the SWCNTs treated at low temperature. It was also found that the hardness change of the SWCNTs is related to the structural change by the HPHT treatments which was based on synchrotron X-ray diffraction measurements

  20. Temperature and pressure adaptation of a sulfate reducer from the deep subsurface

    Directory of Open Access Journals (Sweden)

    Katja eFichtel

    2015-10-01

    Full Text Available Microbial life in deep marine subsurface faces increasing temperatures and hydrostatic pressure with depth. In this study, we have examined growth characteristics and temperature-related adaptation of the Desulfovibrio indonesiensis strain P23 to the in situ pressure of 30 MPa. The strain originates from the deep subsurface of the eastern flank of the Juan de Fuca Ridge (IODP Site U1301. The organism was isolated at 20 °C and atmospheric pressure from ~61 °C-warm sediments approximately five meters above the sediment-basement interface. In comparison to standard laboratory conditions (20 °C and 0.1 MPa, faster growth was recorded when incubated at in situ pressure and high temperature (45 °C, while cell filamentation was induced by further compression. The maximum growth temperature shifted from 48°C at atmospheric pressure to 50°C under high-pressure conditions. Complementary cellular lipid analyses revealed a two-step response of membrane viscosity to increasing temperature with an exchange of unsaturated by saturated fatty acids and subsequent change from branched to unbranched alkyl moieties. While temperature had a stronger effect on the degree of fatty acid saturation and restructuring of main phospholipids, pressure mainly affected branching and length of side chains. The simultaneous decrease of temperature and pressure to ambient laboratory conditions allowed the cultivation of our moderately thermophilic strain. This may in turn be one key to a successful isolation of microorganisms from the deep subsurface adapted to high temperature and pressure.

  1. Temperature control for high pressure processes up to 1400 MPa

    International Nuclear Information System (INIS)

    Reineke, K; Mathys, A; Knorr, D; Heinz, V

    2008-01-01

    Pressure- assisted sterilisation is an emerging technology. Hydrostatic high pressure can reduce the thermal load of the product and this allows quality retention in food products. To guarantee the safety of the sterilisation process it is necessary to investigate inactivation kinetics especially of bacterial spores. A significant roll during the inactivation of microorganisms under high pressure has the thermodynamic effect of the adiabatic heating. To analyse the individual effect of pressure and temperature on microorganism inactivation an exact temperature control of the sample to reach ideal adiabatic conditions and isothermal dwell times is necessary. Hence a heating/cooling block for a high pressure unit (Stansted Mini-Food-lab; high pressure capillary with 300 μL sample volume) was constructed. Without temperature control the sample would be cooled down during pressure built up, because of the non-adiabatic heating of the steel made vessel. The heating/cooling block allows an ideal adiabatic heat up and cooling of the pressure vessel during compression and decompression. The high pressure unit has a pressure build-up rate up to 250 MPa s -1 and a maximum pressure of 1400 MPa. Sebacate acid was chosen as pressure transmitting medium because it had no phase shift over the investigate pressure and temperature range. To eliminate the temperature difference between sample and vessel during compression and decompression phase, the mathematical model of the adiabatic heating/cooling of water and sebacate acid was implemented into a computational routine, written in Test Point. The calculated temperature is the setpoint of the PID controller for the heating/cooling block. This software allows an online measurement of the pressure and temperature in the vessel and the temperature at the outer wall of the vessel. The accurate temperature control, including the model of the adiabatic heating opens up the possibility to realise an ideal adiabatic heating and cooling

  2. 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.

  3. 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...

  4. In-situ, high pressure and temperature experimental determination of hydrogen isotope fractionation between coexisting hydrous melt and silicate-saturated aqueous fluid

    Science.gov (United States)

    Mysen, B. O.

    2012-12-01

    Hydrogen isotope fractionation between water-saturated silicate melt and silicate-saturated aqueous fluid has been determined experimentally, in-situ with the samples in the 450-800C and 101-1567 MPa temperature and pressure range, respectively. The temperatures are, therefore higher than those where hydrogen bonding in fluids and melts is important [1]. The experiments were conducted with a hydrothermal diamond anvil cell (HDAC) as the high-temperature/-pressure tool and vibrational spectroscopy to determine D/H fractionation. Compositions were along the haploandesite join, Na2Si4O9 - Na2(NaAl)4O9 [Al/(Al+Si)=0-0.1], and a 50:50 (by volume) H2O:D2O fluid mixture as starting material. Platinum metal was used to enhance equilibration rate. Isotopic equilibrium was ascertained by using variable experimental duration at given temperature and pressure. In the Al-free Na-silicate system, the enthalpy change of the (D/H) equilibrium of fluid is 3.1±0.7 kJ/mol, whereas for coexisting melt, ΔH=0 kJ/mol within error. With Al/(Al+Si)=0.1, ΔH=5.2±0.9 kJ/mol for fluid and near 0 within error for coexisting melt melt. For the exchange equilibrium between melt and fluid, H2O(melt)+D2O(fluid)=H2O(fluid)+D2O(melt), the ΔH=4.6±0.7 and 6.5±0.7 kJ/mol for the two Al-free and Al-bearing compositions, respectively, respectively. The D/H equilibration within fluids and melts and, therefore, D/H partitioning between coexisting fluid and melt reflect the influence of dissolved H2O(D2O) in melts and dissolved silicate components in H2O(D2O) fluid on their structure. The positive temperature- and pressure-dependence of silicate solubility and on silicate structure in silicate-saturated aqueous fluid governs the D/H fractionation in the fluid because increasing silicate solute concentration in fluid results in silicate polymerization [2]. These structural effects may be analogous to observed solute-dependent oxygen isotope fractionation between brine and CO2 [3]. In the temperature

  5. 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...

  6. 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

  7. Pressure effects on high temperature steam oxidation of Zircaloy-4

    International Nuclear Information System (INIS)

    Park, Kwangheon; Kim, Kwangpyo; Ryu, Taegeun

    2000-01-01

    The pressure effects on Zircaloy-4 (Zry-4) cladding in high temperature steam have been analyzed. A double layer autoclave was made for the high pressure, high temperature oxidation tests. The experimental test temperature range was 700 - 900 deg C, and pressures were 0.1 - 15 MPa. Steam partial pressure turns out to be an important one rather than total pressure. Steam pressure enhances the oxidation rate of Zry-4 exponentially. The enhancement depends on the temperature, and the maximum exists between 750 - 800 deg C. Pre-existing oxide layer decreases the enhancement about 40 - 60%. The acceleration of oxidation rate by high pressure team seems to be originated from the formation of cracks by abrupt transformation of tetragonal phase in oxide, where the un-stability of tetragonal phase comes from the reduction of surface energy by steam. (author)

  8. In-situ Raman spectroscopic study of aluminate speciation in H2O-KOH solutions at high pressures and temperatures

    Science.gov (United States)

    Mookherjee, M.; Keppler, H.; Manning, C. E.

    2009-12-01

    The solubility of corundum in H2O is low even at high pressure and temperatures. Therefore, it is commonly assumed that alumina remains essentially immobile during fluid-rock interaction. However, field and experimental evidence suggests that alumina solubility is strongly enhanced in the presence of silica as well as in alkaline solutions. In order to understand what controls the alumina solubility and how it is enhanced as a function of fluid composition, we conducted Raman-spectroscopic study of Al speciation in aqueous fluids at high pressure and temperature. Experiments were carried out in an externally heated hydrothermal diamond-anvil cell equipped with low-fluorescence diamonds and iridium gaskets. Raman spectra were collected with a Horiba Jobin-Yvon Labram HR spectrometer using the 514 nm line of an argon laser for excitation. In a first series of experiments, the speciation of alumina was studied in a 1 M KOH solution in equilibrium with corundum up to 700 oC and ~1 GPa. The Raman spectra show a prominent band at 618 cm-1 interpreted to arise from Al-O stretching vibrations associated with the tetrahedral [Al(OH)4]1- species. At higher pressure and temperature, an additional vibrational mode appears in the spectra at 374 cm-1 (full width at half maximum ~ 20 cm-1). This feature is tentatively attributed to [(OH)3Al-O-Al(OH)3]2- (Moolenaar et al. 1970, Jour. Phys. Chem., 74, 3629-3636). No evidence for KAl(OH)4 was observed, consistent with piston cylinder experiments at 700 oC and 1 GPa (Wohlers & Manning, 2009, Chem. Geol., 262, 310). Upon cooling from high-pressure and high temperature, slow kinetics of corundum regrowth lead to oversaturation in the solutions, as evidenced by sharp peaks at 930 and 1066 cm-1 observed upon cooling. These features are probably due to colloidal aluminum hydroxide. The results provide the first evidence for aluminate polymerization at high pressure and temperature, and offer insights into the causes for enhancement of

  9. Phase changes induced by guest orientational ordering of filled ice Ih methane hydrate under high pressure and low temperature

    International Nuclear Information System (INIS)

    Hirai, H; Tanaka, T; Yagi, T; Matsuoka, T; Ohishi, Y; Ohtake, M; Yamamoto, Y

    2014-01-01

    Low-temperature and high-pressure experiments were performed with filled ice Ih structure of methane hydrate under pressure and temperature conditions of 2.0 to 77.0 GPa and 30 to 300 K, respectively, using diamond anvil cells and a helium-refrigeration cryostat. Distinct changes in the axial ratios of the host framework were revealed by In-situ X-ray diffractometry. Splitting in the CH vibration modes of the guest methane molecules, which was previously explained by the orientational ordering of the guest molecules, was observed by Raman spectroscopy. The pressure and temperature conditions at the split of the vibration modes agreed well with those of the axial ratio changes. The results indicated that orientational ordering of the guest methane molecules from orientational disordered-state occurred at high pressures and low temperatures, and that this guest ordering led to the axial ratio changes in the host framework. Existing regions of the guest disordered-phase and the guest ordered-phase were roughly estimated by the X-ray data. In addition, above the pressure of the guest-ordered phase, another high pressure phase was developed at a low-temperature region. The deuterated-water host samples were also examined and isotopic effects on the guest ordering and phase changes were observed.

  10. High Pressure Scanning Tunneling Microscopy Studies of Adsorbate Structure and Mobility during Catalytic Reactions. Novel Design of an Ultra High Pressure, High Temperature Scanning Tunneling Microscope System for Probing Catalytic Conversions

    International Nuclear Information System (INIS)

    Tang, David Chi-Wai

    2005-01-01

    The aim of the work presented therein is to take advantage of scanning tunneling microscope's (STM) capability for operation under a variety of environments under real time and at atomic resolution to monitor adsorbate structures and mobility under high pressures, as well as to design a new generation of STM systems that allow imaging in situ at both higher pressures (35 atm) and temperatures (350 C). The design of a high pressure, high temperature scanning tunneling microscope system, that is capable of monitoring reactions in situ at conditions from UHV and ambient temperature up to 1 atm and 250 C, is briefly presented along with vibrational and thermal analysis, as this system serves as a template to improve upon during the design of the new ultra high pressure, high temperature STM. Using this existing high pressure scanning tunneling microscope we monitored the co-adsorption of hydrogen, ethylene and carbon dioxide on platinum (111) and rhodium (111) crystal faces in the mTorr pressure range at 300 K in equilibrium with the gas phase. During the catalytic hydrogenation of ethylene to ethane in the absence of CO the metal surfaces are covered by an adsorbate layer that is very mobile on the time scale of STM imaging. We found that the addition of CO poisons the hydrogenation reaction and induces ordered structures on the single crystal surfaces. Several ordered structures were observed upon CO addition to the surfaces pre-covered with hydrogen and ethylene: a rotated (√19 x √19)R23.4 o on Pt(111), and domains of c(4 x 2)-CO+C 2 H 3 , previously unobserved (4 x 2)-CO+3C 2 H 3 , and (2 x 2)-3CO on Rh(111). A mechanism for CO poisoning of ethylene hydrogenation on the metal single crystals was proposed, in which CO blocks surface metal sites and reduces adsorbate mobility to limit adsorption and reaction rate of ethylene and hydrogen. In order to observe heterogeneous catalytic reactions that occur well above ambient pressure and temperature that more closely

  11. High-temperature transient creep properties of CANDU pressure tubes

    International Nuclear Information System (INIS)

    Fong, R.W.L.; Chow, C.K.

    2002-06-01

    During a hypothetical large break loss-of-coolant accident (LOCA), the coolant flow would be reduced in some fuel channels and would stagnate and cause the fuel temperature to rise and overheat the pressure tube. The overheated pressure tube could balloon (creep radially) into contact with its moderator-cooled calandria tube. Upon contact, the stored thermal energy in the pressure tube is transferred to the calandria tube and into the moderator, which acts as a heat sink. For safety analyses, the modelling of fuel channel deformation behaviour during a large LOCA requires a sound knowledge of the high-temperature creep properties of Zr-2.5Nb pressure tubes. To this extent, a ballooning model to predict pressure-tube deformation was developed by Shewfelt et al., based on creep equations derived using uniaxial tensile specimens. It has been recognized, however, that there is an inherent variability in the high-temperature creep properties of CANDU pressure tubes. The variability, can be due to different tube-manufacturing practices, variations in chemical compositions, and changes in microstructure induced by irradiation during service in the reactor. It is important to quantify the variability of high-temperature creep properties so that accurate predictions on pressure-tube creep behaviour can be made. This paper summarizes recent data obtained from high-temperature uniaxial creep tests performed on specimens taken from both unirradiated (offcut) and irradiated pressure tubes, suggesting that the variability is attributed mainly to the initial differences in microstructure (grain size, shape and preferred orientation) and also from tube-to-tube variations in chemical composition, rather than due to irradiation exposure. These data will provide safety analysts with the means to quantify the uncertainties in the prediction of pressure-tube contact temperatures during a postulated large break LOCA. (author)

  12. 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.

  13. High pressure-temperature polymorphism of 1,1-diamino-2,2-dinitroethylene

    Science.gov (United States)

    Bishop, M. M.; Chellappa, R. S.; Liu, Z.; Preston, D. N.; Sandstrom, M. M.; Dattelbaum, D. M.; Vohra, Y. K.; Velisavljevic, N.

    2014-05-01

    1,1-diamino-2,2-dinitroethylene (FOX-7) is a low sensitivity energetic material with performance comparable to commonly used secondary explosives such as RDX and HMX. At ambient pressure, FOX-7 exhibits complex polymorphism with at least three structurally distinct phases (α, β, and γ). In this study, we have investigated the high pressure-temperature stability of FOX-7 polymorphs using synchrotron mid-infrared (MIR) spectroscopy. At ambient pressure, our MIR spectra and corresponding differential scanning calorimetry (DSC) measurements confirmed the known α → β (~110 °C) and α → β (~160 °C) structural phase transitions; as well as, indicated an additional transition γ → (~210 °C), with the δ phase being stable up to ~251 °C prior to decomposition. In situ MIR spectra obtained during isobaric heating at 0.9 GPa, revealed a potential α → β transition that could occur as early as 180 °C, while β → β+δ phase transition shifted to ~300 °C with suppression of γ phase. Decomposition was observed slightly above 325 °C at 0.9 GPa.

  14. Thermodynamic relations in high temperature and high pressure physics of solids

    International Nuclear Information System (INIS)

    Kumar, Munish

    1998-01-01

    Various possible simple relations based on the exact and approximate thermodynamic relations are derived. These relations can be used to investigate the variation of unit cell volume under the effect of pressure and temperature. Thermal expansivity and compressibility can be investigated directly at any pressure or temperature, or through the knowledge of equation of state (EOS). A relation to determine Anderson-Grueneisen parameter δ T under the effect of pressure is predicted. It is discussed that δ T is independent of pressure and thus Murnaghan equation of state works well in low pressure ranges, while the variation of δ T under high pressure should be taken into account. The product of coefficient of volume thermal expansion and bulk modulus remains constant, is correct at high pressure, provided that the pressure dependence of δ T is considered. (author)

  15. High-Pressure and High-Temperature in situ X-Ray Diffraction Study of FeP2 up to 70 GPa

    International Nuclear Information System (INIS)

    Gu Ting-Ting; Wu Xiang; Qin Shan; Liu Jing; Li Yan-Chun; Zhang Yu-Feng

    2012-01-01

    The high-pressure and high-temperature structural behavior of FeP 2 is investigated by means of synchrotron x-ray powder diffraction combined with a laser heating technique up to 70 GPa and at least 1800 K. No phase transition of FeP 2 occurs up to 68 GPa at room temperature. While a new phase of FeP 2 assigned to the CuAl 2 -type structure (I4/mcm, Z = 4) is observed at 70 GPa after laser-heating. This new phase presents a quenchable property on decompression to ambient conditions. Our results update previous experimental data and are consistent with theoretical studies. (condensed matter: structure, mechanical and thermal properties)

  16. The steam pressure effect on high temperature corrosion of zircaloy-4

    International Nuclear Information System (INIS)

    Kim, K. P.; Park, G. H.

    1998-01-01

    To find the effect of pressure on the high temperature oxidation of zircaloy-4, an autoclave capable of measuring the degree of oxidation at high temperatures and high pressure was manufactured. The degree of high temperature oxidation of zircaloy-4 was measured at three different conditions, high pressure steam, high pressure Ar gas with small amount of steam, and 1 atm steam. All the measurements were done at 750 deg C. The oxide thickness is much thicker in high pressure steam, comparing to that in the 1 atm steam. And, the higher is the steam pressure, the thicker becomes the oxide. No effect was observed in the case of high pressure Ar containing small amount of steam. Many cracks exist on the surface of specimens oxidized at high pressure steam, which come from the enhanced tetragonal to monoclinic phase transformation due to high pressure steam. The enhanced oxidation seems to oxide cracking

  17. Temperature induced development of porous structure of bituminous coal chars at high pressure

    Directory of Open Access Journals (Sweden)

    Natalia Howaniec

    2016-01-01

    Full Text Available The porous structure of chars affects their reactivity in gasification, having an impact on the course and product distribution of the process. The shape, size and connections between pores determine the mechanical properties of chars, as well as heat and mass transport in thermochemical processing. In the study the combined effects of temperature in the range of 973–1273 °K and elevated pressure of 3 MPa on the development of porous structure of bituminous coal chars were investigated. Relatively low heating rate and long residence time characteristic for the in-situ coal conversion were applied. The increase in the temperature to 1173 °K under pressurized conditions resulted in the enhancement of porous structure development reflected in the values of the specific surface area, total pore volume, micropore area and volume, as well as ratio of the micropore volume to the total pore volume. These effects were attributed to the enhanced vaporization and devolatilization, as well as swelling behavior along the increase of temperature and under high pressure, followed by a collapse of pores over certain temperature value. This proves the strong dependence of the porous structure of chars not only on the pyrolysis process conditions but also on the physical and chemical properties of the parent fuel.

  18. A Harsh Environment Wireless Pressure Sensing Solution Utilizing High Temperature Electronics

    Science.gov (United States)

    Yang, Jie

    2013-01-01

    Pressure measurement under harsh environments, especially at high temperatures, is of great interest to many industries. The applicability of current pressure sensing technologies in extreme environments is limited by the embedded electronics which cannot survive beyond 300 °C ambient temperature as of today. In this paper, a pressure signal processing and wireless transmission module based on the cutting-edge Silicon Carbide (SiC) devices is designed and developed, for a commercial piezoresistive MEMS pressure sensor from Kulite Semiconductor Products, Inc. Equipped with this advanced high-temperature SiC electronics, not only the sensor head, but the entire pressure sensor suite is capable of operating at 450 °C. The addition of wireless functionality also makes the pressure sensor more flexible in harsh environments by eliminating the costly and fragile cable connections. The proposed approach was verified through prototype fabrication and high temperature bench testing from room temperature up to 450 °C. This novel high-temperature pressure sensing technology can be applied in real-time health monitoring of many systems involving harsh environments, such as military and commercial turbine engines. PMID:23447006

  19. Rheological assessment of nanofluids at high pressure high temperature

    Science.gov (United States)

    Kanjirakat, Anoop; Sadr, Reza

    2013-11-01

    High pressure high temperature (HPHT) fluids are commonly encountered in industry, for example in cooling and/or lubrications applications. Nanofluids, engineered suspensions of nano-sized particles dispersed in a base fluid, have shown prospective as industrial cooling fluids due to their enhanced rheological and heat transfer properties. Nanofluids can be potentially utilized in oil industry for drilling fluids and for high pressure water jet cooling/lubrication in machining. In present work rheological characteristics of oil based nanofluids are investigated at HPHT condition. Nanofluids used in this study are prepared by dispersing commercially available SiO2 nanoparticles (~20 nm) in a mineral oil. The basefluid and nanofluids with two concentrations, namely 1%, and 2%, by volume, are considered in this investigation. The rheological characteristics of base fluid and the nanofluids are measured using an industrial HPHT viscometer. Viscosity values of the nanofluids are measured at pressures of 100 kPa to 42 MPa and temperatures ranging from 25°C to 140°C. The viscosity values of both nanofluids as well as basefluid are observed to have increased with the increase in pressure. Funded by Qatar National Research Fund (NPRP 08-574-2-239).

  20. In situ detection of two-stage crystallization in ZrTiCuNiBe under high pressure and high temperature

    CERN Document Server

    Sun, L L; Wu, Q; Zhan, Z J; Cao, L M; Wang, L M; Shao, G J; Zhang, J; Wang, W K

    2002-01-01

    Structural changes in bulk metallic Zr sub 4 sub 1 sub . sub 2 Ti sub 1 sub 3 sub . sub 8 Cu sub 1 sub 2 sub . sub 5 Ni sub 1 sub 0 Be sub 2 sub 2 sub . sub 5 glass subjected to heat treatments under high pressure were investigated by means of synchrotron radiation x-ray diffraction (SRXRD). In situ SRXRD measurements showed that the crystallization process of this material is comprised of two stages. Subsequent heating at 10 GPa converts the sample from the amorphous (Am) phase into a metastable fcc phase and then leads to the fcc phase changing back to the Am phase, indicating that there is a kind of 'reversible' phase transition phenomenon occurring in the alloy. Such phenomenon is explained on the basis of free energy considerations.

  1. Trends in high pressure developments for new perspectives

    Science.gov (United States)

    Largeteau, Alain; Prakasam, Mythili

    2018-06-01

    Temperature and Pressure are two parameters in the universe, where pressure represents the largest scale in comparison to temperature. The design of high pressure equipment depends mainly on the media used which could be gas, liquid or solid and the objective could be synthesis of materials or in situ characterization. The development of new research fields requiring high pressure equipment which are currently in Bordeaux - France are based on the historical development of high pressure domain initiated by Professor Gerard DEMAZEAU and his team during the last half century, which is discussed here. The main concepts governing the effect of pressure on materials synthesis is by the combination of high pressure and high temperature which are described with apt examples. There is an upsurge in various technologies for strong development for the synthesis of materials to drive several possibilities, for example: to reach very high density to obtain optical ceramics (by conventional SPS), to diminish parameters (P, T, t) of synthesis (by HP-SPS), to sinter at low temperature thermal sensitive composition (by HyS), to consolidate porous materials (by FIP), to densify biocomposite with cold decontamination (by HHP) simultaneously, etc.

  2. High Pressure and Temperature Effects in Polymers

    Science.gov (United States)

    Bucknall, David; Arrighi, Valeria; Johnston, Kim; Condie, Iain

    Elastomers are widely exploited as the basis for seals in gas and fluid pipelines. The underlying behaviour of these elastomer at the high pressure, elevated temperatures they experience in operation is poorly understood. Consequently, the duty cycle of these materials is often deliberately limited to a few hours, and in order to prevent failure, production is stopped in order to change the seals in critical joints. The result is significant time lost due to bringing down production to change the seals as well as knock on financial costs. In order to address the fundamental nature of the elastomers at their intended operating conditions, we are studying the gas permeation behaviour of hydrogenated natural butyl rubber (HNBR) and fluorinated elastomers (FKM) at a high pressure and elevated temperature. We have developed a pressure system that permits gas permeation studies at gas pressures of up to 5000 psi and operating temperatures up to 150° C. In this paper, we will discuss the nature of the permeation behaviour at these extreme operating conditions, and how this relates to the changes in the polymer structure. We will also discuss the use of graphene-polymer thin layer coatings to modify the gas permeation behaviour of the elastomers.

  3. The increase in Tc for MgB2 superconductor under high pressure

    International Nuclear Information System (INIS)

    Liu, Z-X; Jin, C-Q; You, J-Y; Li, S-C; Zhu, J-L; Yu, R-C; Li, F-Y; Su, S-K

    2002-01-01

    We report in situ high-pressure studies up to 1.0 GPa on MgB 2 superconductor which had been synthesized at high pressure. The as-prepared sample is of high quality as regards having a sharp superconducting transition (T c ) at 39 K. The in situ high-pressure measurements were carried out using a Be-Cu piston-cylinder-type instrument with a mixed oil as the pressure-transmitting medium, which provides a quasi-hydrostatic pressure environment at low temperature. The superconducting transitions were measured using the electrical conductance method. It is found that T c increases with pressure in the initial pressure range, leading to a parabolic-like T c -P evolution

  4. Nb effect on Zr-alloy oxidation under high pressure steam at high temperatures

    International Nuclear Information System (INIS)

    Park, Kwangheon; Yang, Sungwoo; Kim, Kyutae

    2005-01-01

    The high-pressure steam effects on the oxidation of Zircaloy-4 (Zry-4) and Zirlo (Zry-1%Nb) claddings at high temperature have been analyzed. Test temperature range was 700-900degC, and pressures were 1-150 bars. High pressure-steam enhances oxidation of Zry-4, and the dependency of enhancement looks exponential to steam pressure. The origin of the oxidation enhancement turned out to be the formation of cracks in oxide. The loss of tetragonal phase by high-pressure steam seems related to the crack formation. Addition of Nb as an alloying element to Zr alloy reduces significantly the steam pressure effects on oxidation. The higher compressive stresses and the smaller fraction of tetragonal oxides in Zry-1%Nb seem to be the diminished effect of high-pressure steam on oxidation. (author)

  5. 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

  6. In situ study starch gelatinization under ultra-high hydrostatic pressure using synchrotron SAXS

    KAUST Repository

    Yang, Zhi; Gu, Qinfen; Lam, Elisa; Tian, Feng; Chaieb, Saharoui; Hemar, Yacine

    2015-01-01

    The gelatinization of waxy (very low amylose) corn and potato starches by high hydrostatic pressure (HHP) (up to ∼1 GPa) was investigated in situ using synchrotron small-angle X-ray scattering (SAXS) on samples held in a diamond anvil cell (DAC

  7. Pressure sensor for high-temperature liquids

    International Nuclear Information System (INIS)

    Forster, G.A.

    1978-01-01

    A pressure sensor for use in measuring pressures in liquid at high temperatures, especially such as liquid sodium or liquid potassium, comprises a soft diaphragm in contact with the liquid. The soft diaphragm is coupled mechanically to a stiff diaphragm. Pressure is measured by measuring the displacement of both diaphragms, typically by measuring the capacitance between the stiff diaphragm and a fixed plate when the stiff diaphragm is deflected in response to the measured pressure through mechanical coupling from the soft diaphragm. Absolute calibration is achieved by admitting gas under pressure to the region between diaphragms and to the region between the stiff diaphragm and the fixed plate, breaking the coupling between the soft and stiff diaphragms. The apparatus can be calibrated rapidly and absolutely

  8. 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

  9. High pressure neutron and X-ray diffraction at low temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Ridley, Christopher J.; Kamenev, Konstantin V. [Edinburgh Univ. (United Kingdom). School of Engineering and the Centre for Science at Extreme Conditions

    2014-04-01

    This paper presents a review of techniques and considerations in the design and construction of high pressure, low temperature diffraction experiments. Also intended as an introductory text to new high pressure users, the crucial aspects of pressure cell design are covered. The general classification of common designs, and a discussion into the key beam interaction, mechanical, and thermal properties of commonly used materials is given. The advantages of different materials and high pressure cell classifications are discussed, and examples of designs developed for low temperature diffraction studies are presented, and compared. (orig.)

  10. High pressure neutron and X-ray diffraction at low temperatures

    International Nuclear Information System (INIS)

    Ridley, Christopher J.; Kamenev, Konstantin V.

    2014-01-01

    This paper presents a review of techniques and considerations in the design and construction of high pressure, low temperature diffraction experiments. Also intended as an introductory text to new high pressure users, the crucial aspects of pressure cell design are covered. The general classification of common designs, and a discussion into the key beam interaction, mechanical, and thermal properties of commonly used materials is given. The advantages of different materials and high pressure cell classifications are discussed, and examples of designs developed for low temperature diffraction studies are presented, and compared. (orig.)

  11. Measurement of rock properties at elevated pressures and temperatures

    International Nuclear Information System (INIS)

    Pincus, H.J.; Hoskins, E.R.

    1985-01-01

    The papers in this volume were presented at an ASTM symposium held on 20 June 1983 in conjunction with the 24th Annual Rock Mechanics Symposium at Texas A and M University, College Station, TX. The purpose of these papers is to present recent developments in the measurement of rock properties at elevated pressures and temperatures, and to examine and interpret the data produced by such measurement. The need for measuring rock properties at elevated pressures and temperatures has become increasingly important in recent years. Location and design of nuclear waste repositories, development of geothermal energy sites, and design and construction of deep excavations for civil, military, and mining engineering require significantly improved capabilities for measuring rock properties under conditions substantially different from those prevailing in most laboratory and in situ work. The development of high-pressure, high-temperature capabilities is also significant for the analysis of tectonic processes

  12. Quenching ilmenite with a high-temperature and high-pressure phase using super-high-energy ball milling.

    Science.gov (United States)

    Hashishin, Takeshi; Tan, Zhenquan; Yamamoto, Kazuhiro; Qiu, Nan; Kim, Jungeum; Numako, Chiya; Naka, Takashi; Valmalette, Jean Christophe; Ohara, Satoshi

    2014-04-25

    The mass production of highly dense oxides with high-temperature and high-pressure phases allows us to discover functional properties that have never been developed. To date, the quenching of highly dense materials at the gramme-level at ambient atmosphere has never been achieved. Here, we provide evidence of the formation of orthorhombic Fe2TiO4 from trigonal FeTiO3 as a result of the high-temperature (>1250 K) and high-pressure (>23 GPa) condition induced by the high collision energy of 150 gravity generated between steel balls. Ilmenite was steeply quenched by the surrounding atmosphere, when iron-rich ilmenite (Fe2TiO4) with a high-temperature and high-pressure phase was formed by planetary collisions and was released from the collision points between the balls. Our finding allows us to infer that such intense planetary collisions induced by high-energy ball milling contribute to the mass production of a high-temperature and high-pressure phase.

  13. A high-temperature, ambient-pressure ultra-dry operando reactor cell for Fourier-transform infrared spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Köck, Eva-Maria; Kogler, Michaela; Pramsoler, Reinhold; Klötzer, Bernhard; Penner, Simon, E-mail: simon.penner@uibk.ac.at [Institute of Physical Chemistry, University of Innsbruck, Innrain 80-82, A-6020 Innsbruck (Austria)

    2014-08-15

    The construction of a newly designed high-temperature, high-pressure FT-IR reaction cell for ultra-dry in situ and operando operation is reported. The reaction cell itself as well as the sample holder is fully made of quartz glass, with no hot metal or ceramic parts in the vicinity of the high-temperature zone. Special emphasis was put on chemically absolute water-free and inert experimental conditions, which includes reaction cell and gas-feeding lines. Operation and spectroscopy up to 1273 K is possible, as well as pressures up to ambient conditions. The reaction cell exhibits a very easy and variable construction and can be adjusted to any available FT-IR spectrometer. Its particular strength lies in its possibility to access and study samples under very demanding experimental conditions. This includes studies at very high temperatures, e.g., for solid-oxide fuel cell research or studies where the water content of the reaction mixtures must be exactly adjusted. The latter includes all adsorption studies on oxide surfaces, where the hydroxylation degree is of paramount importance. The capability of the reaction cell will be demonstrated for two selected examples where information and in due course a correlation to other methods can only be achieved using the presented setup.

  14. High pressure-temperature polymorphism of 1,1-diamino-2,2-dinitroethylene

    International Nuclear Information System (INIS)

    Bishop, M M; Dattelbaum, D M; Velisavljevic, N; Chellappa, R S; Liu, Z; Preston, D N; Sandstrom, M M; Vohra, Y K

    2014-01-01

    1,1-diamino-2,2-dinitroethylene (FOX-7) is a low sensitivity energetic material with performance comparable to commonly used secondary explosives such as RDX and HMX. At ambient pressure, FOX-7 exhibits complex polymorphism with at least three structurally distinct phases (α, β, and γ). In this study, we have investigated the high pressure-temperature stability of FOX-7 polymorphs using synchrotron mid-infrared (MIR) spectroscopy. At ambient pressure, our MIR spectra and corresponding differential scanning calorimetry (DSC) measurements confirmed the known α → β (∼110 °C) and α → β (∼160 °C) structural phase transitions; as well as, indicated an additional transition γ → (∼210 °C), with the δ phase being stable up to ∼251 °C prior to decomposition. In situ MIR spectra obtained during isobaric heating at 0.9 GPa, revealed a potential α → β transition that could occur as early as 180 °C, while β → β+δ phase transition shifted to ∼300 °C with suppression of γ phase. Decomposition was observed slightly above 325 °C at 0.9 GPa.

  15. High Accuracy, Miniature Pressure Sensor for Very High Temperatures, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — SiWave proposes to develop a compact, low-cost MEMS-based pressure sensor for very high temperatures and low pressures in hypersonic wind tunnels. Most currently...

  16. High pressure and temperature structure of liquid and solid Cd: implications for the melting curve of Cd

    International Nuclear Information System (INIS)

    Raju, S V; Williams, Q; Geballe, Z M; Godwal, B K; Jeanloz, R; Kalkan, B

    2014-01-01

    The structure of cadmium was characterized in both the solid and liquid forms at pressures to 10 GPa using in situ x-ray diffraction measurements in a resistively heated diamond anvil cell. The distorted hexagonal structure of solid cadmium persists at high pressures and temperatures, with anomalously large c/a ratio of Cd becoming larger as the melting curve is approached. The measured structure factor S(Q) for the melt reveals that the cadmium atoms are spaced about 0.6 Angstroms apart. The melt structure remains notably constant with increasing pressure, with the first peak in the structure factor remaining mildly asymmetric, in accord with the persistence of an anisotropic bonding environment within the liquid. Evolution of powder diffraction patterns up to the temperature of melting revealed the stability of the ambient-pressure hcp structure up to a pressure of 10 GPa. The melting curve has a positive Clausius–Clapeyron slope, and its slope is in good agreement with data from other techniques. We find deviations in the melting curve from Lindemann law type behavior for pressures above 1 GPa. (paper)

  17. 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.

  18. Spectroscopic studies of sulfite-based polyoxometalates at high temperature and high pressure

    International Nuclear Information System (INIS)

    Quesada Cabrera, Raul; Firth, Steven; Blackman, Christopher S.; Long, De-Liang; Cronin, Leroy; McMillan, Paul F.

    2012-01-01

    Structural changes occurring within non-conventional Dawson-type [α/β-Mo 18 O 54 (SO 3 ) 2 ] 4− polyanions in the form of tetrapentylammonium salts were studied by a combination of IR, Raman and visible spectroscopy at high temperature and high pressure. Evidence of the formation of bronze-type materials above 400 K and also upon pressurization to 8 GPa is presented. This conclusion is suggested to be a general result for polyoxometalate compounds subjected to extreme conditions and it opens opportunities for the design of new materials with interesting optical and electronic properties. - Graphical abstract: Structural changes occurring within non-conventional Dawson-type [α/β-Mo 18 O 54 (SO 3 ) 2 ] 4− polyanions in the form of tetrapentylammonium salts were studied by a combination of IR, Raman and visible spectroscopy at high temperature and high pressure. Evidence of the formation of bronze-type materials above 400 K and also upon pressurization to 8 GPa is presented. This conclusion is suggested to be a general result for polyoxometalate compounds subjected to extreme conditions and it opens opportunities for the design of new materials with interesting optical and electronic properties. Highlights: ► Spectroscopy studies of non-conventional Wells–Dawson polyoxometalates (POMs) at high temperature and high pressure. ► Discussion on the stability of two POM isomers. ► Local formation of bronze-like materials: possibilities for a new synthetic method at high pressure from POM precursors.

  19. $\\mu$SR-Measurements under High Pressure and at Low Temperatures

    CERN Multimedia

    2002-01-01

    High pressure causes changes in the volume available to each atom in a solid and will therefore influence local properties like the electronic charge and spin densities and, in the case of magnetic materials, the spin ordering.\\\\ \\\\ The positive muon is known to be an interesting probe particle for the study of certain problems in magnetism. It has in fact been used for one high pressure experiment earlier in CERN, but the present experiments aim at more systematic studie For this purpose it is necessary to carry out pressure experiments at low temperatures. The new experiments use a helium gas pressure system, which covers the temperature range 10-300 K at pressures up to 14 Kbar.\\\\ \\\\ Experiments are in progress on \\item 1)~~~~Ferromagnetic metals like Fe, Co, Ni where the pressure dependence of the local magnetic field ~~~is studied at 77 K and at room temperature. \\item 2)~~~~Knight shifts in semimetals, where in the case of Sb strong variations with temperature and ~~~pressure are observed. \\end{enumerat...

  20. 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.

  1. Thermodynamic properties of OsB under high temperature and high pressure

    Science.gov (United States)

    Chen, Hai-Hua; Li, Zuo; Cheng, Yan; Bi, Yan; Cai, Ling-Cang

    2011-09-01

    The energy-volume curves of OsB have been obtained using the first-principles plane-wave ultrasoft-pseudopotential density functional theory (DFT) within the generalized gradient approximation (GGA) and local density approximation (LDA). Using the quasi-harmonic Debye model we first analyze the specific heat, the coefficients of thermal expansion as well as the thermodynamic Grüneisen parameter of OsB in a wide temperature range at high pressure. At temperature 300 K, the coefficients of thermal expansion αV by LDA and GGA calculations are 1.67×10 -5 1/K and 2.01×10 -5 1/K, respectively. The specific heat of OsB at constant pressure (volume) is also calculated. Meanwhile, we find that the Debye temperature of OsB increases monotonically with increasing pressure. The present study leads to a better understanding of how the OsB materials respond to pressure and temperature.

  2. Microsoft excel spreadsheets for calculation of P-V-T relations and thermodynamic properties from equations of state of MgO, diamond and nine metals as pressure markers in high-pressure and high-temperature experiments

    Science.gov (United States)

    Sokolova, Tatiana S.; Dorogokupets, Peter I.; Dymshits, Anna M.; Danilov, Boris S.; Litasov, Konstantin D.

    2016-09-01

    We present Microsoft Excel spreadsheets for calculation of thermodynamic functions and P-V-T properties of MgO, diamond and 9 metals, Al, Cu, Ag, Au, Pt, Nb, Ta, Mo, and W, depending on temperature and volume or temperature and pressure. The spreadsheets include the most common pressure markers used in in situ experiments with diamond anvil cell and multianvil techniques. The calculations are based on the equation of state formalism via the Helmholtz free energy. The program was developed using Visual Basic for Applications in Microsoft Excel and is a time-efficient tool to evaluate volume, pressure and other thermodynamic functions using T-P and T-V data only as input parameters. This application is aimed to solve practical issues of high pressure experiments in geosciences and mineral physics.

  3. Diffraction studies of order-disorder at high pressures and temperatures

    International Nuclear Information System (INIS)

    Parise, John B.; Antao, Sytle M.; Martin, Charles D.; Crichton, Wilson

    2005-01-01

    Recent developments at synchrotron X-ray beamlines now allow collection of data suitable for structure determination and Rietveld structure refinement at high pressures and temperatures on challenging materials. These include materials, such as dolomite (CaMg(CO 3 ) 2 ) that tends to calcine at high temperatures, and Fe-containing materials, such as the spinel MgFe 2 O 4 , which tend to undergo changes in oxidation state. Careful consideration of encapsulation along with the use of radial collimation produced powder diffraction patterns virtually free of parasitic scattering from the cell in the case of large volume high-pressure experiments. These features have been used to study a number of phase transitions, especially those where superior signal-to-noise discrimination is required to distinguish weak ordering reflections. The structures adopted by dolomite, and CaSO4, anhydrite, were determined from 298 to 1466 K at high pressures. Using laser-heated diamond-anvil cells to achieve simultaneous high pressure and temperature conditions, we have observed CaSO 4 undergo phase transitions to the monazite type and at highest pressure and temperature to crystallize in the barite-type structure. On cooling, the barite structure distorts, from an orthorhombic to a monoclinic lattice, to produce the AgMnO 4 -type structure.

  4. Thermal equation of state of synthetic orthoferrosilite at lunar pressures and temperatures

    NARCIS (Netherlands)

    de Vries, J.; Jacobs, J.M.G.; van den Berg, A.P.; Wehber, M.; Lathe, C.; McCammon, C.A.; van Westrenen, W.

    2013-01-01

    Iron-rich orthopyroxene plays an important role in models of the thermal and magmatic evolution of the Moon, but its density at high pressure and high temperature is not well-constrained. We present in situ measurements of the unit-cell volume of a synthetic polycrystalline end-member

  5. Equation of state, phase stability, and phase transformations of uranium-6 wt. % niobium under high pressure and temperature

    Science.gov (United States)

    Zhang, Jianzhong; Vogel, Sven; Brown, Donald; Clausen, Bjorn; Hackenberg, Robert

    2018-05-01

    In-situ time-of-flight neutron diffraction experiments were conducted on the uranium-niobium alloy with 6 wt. % Nb (U-6Nb) at pressures up to 4.7 GPa and temperatures up to 1073 K. Upon static compression at room temperature, the monoclinic structure of U-6Nb (α″ U-6Nb) remains stable up to the highest experimental pressure. Based on the pressure-volume measurements at room temperature, the least-squares fit using the finite-strain equation of state (EOS) yields an isothermal bulk modulus of B0 = 127 ± 2 GPa for the α″-phase of U-6Nb. The calculated zero-pressure bulk sound speed from this EOS is 2.706 ± 0.022 km/s, which is in good agreement with the linear extrapolation of the previous Hugoniot data above 12 GPa for α″ U-6Nb, indicating that the dynamic response under those shock-loading conditions is consistent with the stabilization of the initial monoclinic phase of U-6Nb. Upon heating at ambient and high pressures, the metastable α″ U-6Nb exhibits complex transformation paths leading to the diffusional phase decomposition, which are sensitive to applied pressure, stress state, and temperature-time path. These findings provide new insight into the behavior of atypical systems such as U-Nb and suggest that the different U-Nb phases are separated by rather small energies and hence highly sensitive to compositional, thermal, and mechanical perturbations.

  6. Phase stability of TiH{sub 2} under high pressure and temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Selva Vennila, R.; Durygin, A.; Saxena, S.K. [Center for Study of Matter at Extreme Conditions (CeSMEC), Florida International University, VH-150, University Park, Miami, FL 33199 (United States); Merlini, Marco [European Synchrotron Radiation Facility (ESRF), Grenoble 38043 (France); Wang, Zhongwu [Cornell High Energy Synchrotron Source (CHESS), Wilson Laboratory, Cornell University, Ithaca, NY 14853 (United States)

    2008-11-15

    Phase stability of titanium hydride (TiH{sub 2}) was studied at high pressure-high temperature conditions using synchrotron radiation under non-hydrostatic conditions. Resistive heating method was used to heat the sample to a maximum temperature of 873 K in a diamond anvil cell (DAC) under pressure up to 12 GPa. Pressure-temperature behavior was studied by varying the temperature upto 823 K in steps of 50 K with pressure variations within 3 GPa. Structural phase transformation from tetragonal (I4/mmm) to cubic (Fm-3 m) was observed with increase in temperature. Tetragonal phase was found to be stabilized when the sample was subjected to pressure and temperature cycle. (author)

  7. Transformations in refractory compounds, caused by high pressures and temperatures

    International Nuclear Information System (INIS)

    Zajnulin, Yu.G.; Alyamovskij, S.I.; Shvejkin, G.P.

    1979-01-01

    Considered is the effect of high pressures and temperatures on structural features of refractory carbides, nitrides and monooxides of transition metals. The results are discussed on the basis of one component of the theory on daltonides and bertollides by N.S. Kurnakov - the theory of imaginary compounds, developed by G.B. Bokij. Several new ideas, resulting from this consideration, are formulated, It is shown that at high pressures and temperatures it is possible to obtain new electron modifications of compounds and to expand sufficiently the region of the existance of variable composition phases. The concept on imaginary compounds is shown to be true. A supposition is made on realization of numerous imaginary compounds at high pressures and temperatures. Other ways of production of imaginary compounds are recommended

  8. In situ neutron diffraction studies of high density amorphous ice under pressure

    International Nuclear Information System (INIS)

    Klotz, Stefan; Straessle, Th; Saitta, A M; Rousse, G; Hamel, G; Nelmes, R J; Loveday, J S; Guthrie, M

    2005-01-01

    We review recent in situ neutron diffraction studies on the structural pressure dependence and the recrystallization of dense amorphous ices up to 2 GPa. Progress in high pressure techniques and data analysis methods allows the reliable determination of all three partial structure factors of amorphous ice under pressure. The strong pressure dependence of the g OO (r) correlation function shows that the isothermal compression of high density amorphous ice (HDA) at 100 K is achieved by a contraction (∼ 20%) of the second-neighbour coordination shell leading to a strong increase in coordination. The g DD (r) and g OD (r) structure factors are, in contrast, only weakly sensitive to pressure. These data allow a comparison with structural features of the recently reported 'very high density amorphous ice' (VHDA) which indicates that VHDA at ambient pressure is very similar to compressed HDA, at least up to the second-neighbour shell. The recrystallization of HDA has been investigated in the range 0.3-2 GPa. It is shown that hydrogen-disordered phases are produced which normally grow only from the liquid, such as ice XII, and in particular ice IV. These findings are in good agreement with results on quench-recovered samples

  9. Carvacrol suppresses high pressure high temperature inactivation of Bacillus cereus spores.

    Science.gov (United States)

    Luu-Thi, Hue; Corthouts, Jorinde; Passaris, Ioannis; Grauwet, Tara; Aertsen, Abram; Hendrickx, Marc; Michiels, Chris W

    2015-03-16

    The inactivation of bacterial spores generally proceeds faster and at lower temperatures when heat treatments are conducted under high pressure, and high pressure high temperature (HPHT) processing is, therefore, receiving an increased interest from food processors. However, the mechanisms of spore inactivation by HPHT treatment are poorly understood, particularly at moderately elevated temperature. In the current work, we studied inactivation of the spores of Bacillus cereus F4430/73 by HPHT treatment for 5 min at 600MPa in the temperature range of 50-100°C, using temperature increments of 5°C. Additionally, we investigated the effect of the natural antimicrobial carvacrol on spore germination and inactivation under these conditions. Spore inactivation by HPHT was less than about 1 log unit at 50 to 70°C, but gradually increased at higher temperatures up to about 5 log units at 100°C. DPA release and loss of spore refractility in the spore population were higher at moderate (≤65°C) than at high (≥70°C) treatment temperatures, and we propose that moderate conditions induced the normal physiological pathway of spore germination resulting in fully hydrated spores, while at higher temperatures this pathway was suppressed and replaced by another mechanism of pressure-induced dipicolinic acid (DPA) release that results only in partial spore rehydration, probably because spore cortex hydrolysis is inhibited. Carvacrol strongly suppressed DPA release and spore rehydration during HPHT treatment at ≤65°C and also partly inhibited DPA release at ≥65°C. Concomitantly, HPHT spore inactivation was reduced by carvacrol at 65-90°C but unaffected at 95-100°C. Copyright © 2014 Elsevier B.V. All rights reserved.

  10. High pressure apparatus for neutron scattering at low temperature

    International Nuclear Information System (INIS)

    Munakata, Koji; Uwatoko, Yoshiya; Aso, Naofumi

    2010-01-01

    Effects of pressure on the physical properties are very important for understanding highly correlated electron systems, in which pressure-induced attractive phenomena such as superconductivity and magnetically ordered non-Fermi liquid have been observed. Up to now, many scientists have developed a lot of high pressure apparatus for each purpose. The characteristic features of various materials and pressure transmitting media for use of high pressure apparatus are reported. Then, two kinds of clamp type high-pressure cell designed for low-temperature neutron diffraction measurements are shown; one is a piston cylinder type high-pressure cell which can be attached to the dilution refrigerator, and the other one is a newly-developed cubic anvil type high-pressure cell which can generate pressure above 7GPa. We also introduce the results of magnetic neutron scattering under pressure on a pressure-induced superconducting ferromagnet UGe 2 in use of the piston cylinder type clamp cell, and those on an iron arsenide superconductor SrFe 2 As 2 in use of the cubic anvil type clamp cell. (author)

  11. High Temperature Dynamic Pressure Measurements Using Silicon Carbide Pressure Sensors

    Science.gov (United States)

    Okojie, Robert S.; Meredith, Roger D.; Chang, Clarence T.; Savrun, Ender

    2014-01-01

    Un-cooled, MEMS-based silicon carbide (SiC) static pressure sensors were used for the first time to measure pressure perturbations at temperatures as high as 600 C during laboratory characterization, and subsequently evaluated in a combustor rig operated under various engine conditions to extract the frequencies that are associated with thermoacoustic instabilities. One SiC sensor was placed directly in the flow stream of the combustor rig while a benchmark commercial water-cooled piezoceramic dynamic pressure transducer was co-located axially but kept some distance away from the hot flow stream. In the combustor rig test, the SiC sensor detected thermoacoustic instabilities across a range of engine operating conditions, amplitude magnitude as low as 0.5 psi at 585 C, in good agreement with the benchmark piezoceramic sensor. The SiC sensor experienced low signal to noise ratio at higher temperature, primarily due to the fact that it was a static sensor with low sensitivity.

  12. CMOS-compatible ruggedized high-temperature Lamb wave pressure sensor

    International Nuclear Information System (INIS)

    Kropelnicki, P; Mu, X J; Randles, A B; Cai, H; Ang, W C; Tsai, J M; Muckensturm, K-M; Vogt, H

    2013-01-01

    This paper describes the development of a novel ruggedized high-temperature pressure sensor operating in lateral field exited (LFE) Lamb wave mode. The comb-like structure electrodes on top of aluminum nitride (AlN) were used to generate the wave. A membrane was fabricated on SOI wafer with a 10 µm thick device layer. The sensor chip was mounted on a pressure test package and pressure was applied to the backside of the membrane, with a range of 20–100 psi. The temperature coefficient of frequency (TCF) was experimentally measured in the temperature range of −50 °C to 300 °C. By using the modified Butterworth–van Dyke model, coupling coefficients and quality factor were extracted. Temperature-dependent Young's modulus of composite structure was determined using resonance frequency and sensor interdigital transducer (IDT) wavelength which is mainly dominated by an AlN layer. Absolute sensor phase noise was measured at resonance to estimate the sensor pressure and temperature sensitivity. This paper demonstrates an AlN-based pressure sensor which can operate in harsh environment such as oil and gas exploration, automobile and aeronautic applications. (paper)

  13. A High-Temperature Piezoresistive Pressure Sensor with an Integrated Signal-Conditioning Circuit

    Directory of Open Access Journals (Sweden)

    Zong Yao

    2016-06-01

    Full Text Available This paper focuses on the design and fabrication of a high-temperature piezoresistive pressure sensor with an integrated signal-conditioning circuit, which consists of an encapsulated pressure-sensitive chip, a temperature compensation circuit and a signal-conditioning circuit. A silicon on insulation (SOI material and a standard MEMS process are used in the pressure-sensitive chip fabrication, and high-temperature electronic components are adopted in the temperature-compensation and signal-conditioning circuits. The entire pressure sensor achieves a hermetic seal and can be operated long-term in the range of −50 °C to 220 °C. Unlike traditional pressure sensor output voltage ranges (in the dozens to hundreds of millivolts, the output voltage of this sensor is from 0 V to 5 V, which can significantly improve the signal-to-noise ratio and measurement accuracy in practical applications of long-term transmission based on experimental verification. Furthermore, because this flexible sensor’s output voltage is adjustable, general follow-up pressure transmitter devices for voltage converters need not be used, which greatly reduces the cost of the test system. Thus, the proposed high-temperature piezoresistive pressure sensor with an integrated signal-conditioning circuit is expected to be highly applicable to pressure measurements in harsh environments.

  14. Electrochemical cell and electrode designs for high-temperature/high-pressure kinetic measurements

    International Nuclear Information System (INIS)

    Nagy, Z.; Yonco, R.M.

    1987-05-01

    Many corrosion processes of interest to the nuclear power industry occur in high-temperature/high-pressure aqueous systems. The investigation of the kinetics of the appropriate electrode reactions is a serious experimental challenge, partially because of the high temperatures and pressures and partially because many of these reactions are very rapid, requiring fast relaxation measurements. An electrochemical measuring system is described which is suitable for measurements of the kinetics of fast electrode reactions at temperatures extending to at least 300 0 C and pressures to at least 10 MPa (100 atmospheres). The system includes solution preparation and handling equipment, the electrochemical cell, and several electrode designs. One of the new designs is a coaxial working electrode-counter electrode assembly; this electrode can be used with very fast-rising pulses, and it provides a well defined, repeatedly-polishable working surface. Low-impedance reference electrodes are also described, based on electrode concepts responding to the pH or the redox potential of the test solution. Additionally, a novel, long-life primary reference electrode design is reported, based on a modification of the external, pressure-balanced Ag/AgCl reference electrode

  15. Electrochemical cell and electrode designs for high-temperature/high-pressure kinetic measurements

    International Nuclear Information System (INIS)

    Nagy, Z.; Yonco, R.M.

    1988-01-01

    Many corrosion processes of interest to the nuclear power industry occur in high-temperature/high-pressure aqueous systems. The investigation of the kinetics of the appropriate electrode reactions is a serious experimental challenge, partially because of the high temperatures and pressures and partially because many of these reactions are very rapid, requiring fast relaxation measurements. An electrochemical measuring system is described which is suitable for measurements of the kinetics of fast electrode reactions at temperatures extending to at least 300 0 C and pressures to at least 10 MPa (100 atmospheres). The system includes solution preparation and handling equipment, the electrochemical cell, and several electrode designs. One of the new designs is a coaxial working electrode-counter electrode assembly; this electrode can be used with very fast-rising pulses, and it provides a well defined, repeatedly-polishable working surface. Low-impedance reference electrodes are also described, based on electrode concepts responding to the pH or the redox potential of the test solution. Additionally, a novel, long-life primary reference electrode design is reported, based on a modification of the external, pressure-balanced Ag/AgCl reference electrode

  16. Self-contained high-pressure chambers for study on the Moessbauer effect at low temperatures

    International Nuclear Information System (INIS)

    Stepanov, G.N.

    1980-01-01

    Designs of two high-pressure chambers intended for studying the Moessbauer effect at low temperatures are described. The high-pressure chamber of the Bridgman anvil type is made of non magnetic materials and intended for operation at helium temperatures. The chamber employs a superconducting pressure gage. A sample and superconducting pressure gage are surrounded with a liquid medium of a high pressure at a room temperature. Measurements of the pressure were taken during heating the chamber in the vapours of liquid helium according to the known dependence of the lead superconducting transition temperature on pressure. The other high-pressure chamber of the piston-to-cylinder type can be used to study the Moessbauer effect at temperatures ranging from 4 to 300 K. Pressure in the chamber is measured by means of the superconducting pressure gage. The maximum pressure obtained in the chamber constitutes 25 kbar

  17. High-pressure powder x-ray diffraction experiments on Zn at low temperature

    CERN Document Server

    Takemura, K; Fujihisa, H; Kikegawa, T

    2002-01-01

    High-pressure powder x-ray diffraction experiments have been performed on Zn with a He-pressure medium at low temperature. When the sample was compressed in the He medium at low temperature, large nonhydrostaticity developed, yielding erroneous lattice parameters. On the other hand, when the pressure was changed at high temperatures, good hydrostaticity was maintained. No anomaly in the volume dependence of the c/a axial ratio has been found.

  18. The increase in T sub c for MgB sub 2 superconductor under high pressure

    CERN Document Server

    Liu, Z X; You, J Y; Li, S C; Zhu, J L; Yu, R C; Li, F Y; Su, S K

    2002-01-01

    We report in situ high-pressure studies up to 1.0 GPa on MgB sub 2 superconductor which had been synthesized at high pressure. The as-prepared sample is of high quality as regards having a sharp superconducting transition (T sub c) at 39 K. The in situ high-pressure measurements were carried out using a Be-Cu piston-cylinder-type instrument with a mixed oil as the pressure-transmitting medium, which provides a quasi-hydrostatic pressure environment at low temperature. The superconducting transitions were measured using the electrical conductance method. It is found that T sub c increases with pressure in the initial pressure range, leading to a parabolic-like T sub c -P evolution.

  19. Inelastic X-ray scattering experiments at extreme conditions: high temperatures and high pressures

    Directory of Open Access Journals (Sweden)

    S.Hosokawa

    2008-03-01

    Full Text Available In this article, we review the present status of experimental techniques under extreme conditions of high temperature and high pressure used for inelastic X-ray scattering (IXS experiments of liquid metals, semiconductors, molten salts, molecular liquids, and supercritical water and methanol. For high temperature experiments, some types of single-crystal sapphire cells were designed depending on the temperature of interest and the sample thickness for the X-ray transmission. Single-crystal diamond X-ray windows attached to the externally heated high-pressure vessel were used for the IXS experiment of supercritical water and methanol. Some typical experimental results are also given, and the perspective of IXS technique under extreme conditions is discussed.

  20. Pressure balanced type membrane covered polarographic oxygen detectors for use in high temperature-high pressure water, (1)

    International Nuclear Information System (INIS)

    Nakayama, Norio; Uchida, Shunsuke

    1984-01-01

    A pressure balanced type membrane covered polarographic oxygen detector was developed to determine directly oxygen concentrations in high temperature, high pressure water without cooling and pressure reducing procedures. The detector is characterized by the following features: (1) The detector body and the membrane for oxygen penetration are made of heat resistant resin. (2) The whole detector body is contained in a pressure chamber where interior and exterior pressures of the detector are balanced. (3) Thermal expansion of the electrolyte is absorbed by deformation of a diaphragm attached to the detector bottom. (4) The effect of dissolved Ag + on the signal current is eliminated by applying a guard electrode. As a result of performance tests at elevated temperature, it was demonstrated that a linear relationship between oxygen concentration and signal current was obtained up to 285 0 C, which was stabilized by the guard electrode. The minimum O 2 concentration detectable was 0.03ppm (9.4 x 10 -7 mol/kg). (author)

  1. Wireless contactless pressure measurement of an LC passive pressure sensor with a novel antenna for high-temperature applications

    International Nuclear Information System (INIS)

    Li Chen; Tan Qiu-Lin; Xue Chen-Yang; Zhang Wen-Dong; Li Yun-Zhi; Xiong Ji-Jun

    2015-01-01

    In this paper, a novel antenna is proposed for high-temperature testing, which can make the high-temperature pressure characteristics of a wireless passive ceramic pressure sensor demonstrated at up to a temperature of 600 °C. The design parameters of the antenna are similar to those of the sensor, which will increase the coupling strength between the sensor and testing antenna. The antenna is fabricated in thick film integrated technology, and the properties of the alumina ceramic and silver ensure the feasibility of the antenna in high-temperature environments. The sensor, coupled with the ceramic antenna, is investigated using a high-temperature pressure testing platform. The experimental measurement results show that the pressure signal in a harsh environment can be detected by the frequency diversity of the sensor. (paper)

  2. Pressure effect of glass transition temperature in Zr46.8Ti8.2Cu7.5Ni10Be27.5 bulk metallic glass

    DEFF Research Database (Denmark)

    Jiang, Jianzhong; Roseker, W.; Sikorski, M.

    2004-01-01

    Pressure effects on glass transition temperature and supercooled liquid region of a Zr46.8Ti8.2Cu7.5Ni10Be27.5 bulk glass have been investigated by performing in situ high-temperature and high-pressure x-ray powder diffraction measurements using synchrotron radiation. The glass transition was det...... range of 0-2.2 GPa. This method opens a possibility to study the pressure effect of glass transition process in glassy systems under high pressures (>1 GPa). (C) 2004 American Institute of Physics.......Pressure effects on glass transition temperature and supercooled liquid region of a Zr46.8Ti8.2Cu7.5Ni10Be27.5 bulk glass have been investigated by performing in situ high-temperature and high-pressure x-ray powder diffraction measurements using synchrotron radiation. The glass transition...... was detected from the change of the slope of peak position as a function of temperature. It is found that the glass transition temperature increases with pressure by 4.4 K/GPa for the Zr46.8Ti8.2Cu7.5Ni10Be27.5 bulk glass, and the supercooled liquid range decreases with pressure by 2.9 K/GPa in a pressure...

  3. The analysis of energy efficiency in water electrolysis under high temperature and high pressure

    Science.gov (United States)

    Hourng, L. W.; Tsai, T. T.; Lin, M. Y.

    2017-11-01

    This paper aims to analyze the energy efficiency of water electrolysis under high pressure and high temperature conditions. The effects of temperature and pressure on four different kinds of reaction mechanisms, namely, reversible voltage, activation polarization, ohmic polarization, and concentration polarization, are investigated in details. Results show that the ohmic and concentration over-potentials are increased as temperature is increased, however, the reversible and activation over-potentials are decreased as temperature is increased. Therefore, the net efficiency is enhanced as temperature is increased. The efficiency of water electrolysis at 350°C/100 bars is increased about 17%, compared with that at 80°C/1bar.

  4. The thermal equation of state of FeTiO3 ilmenite based on in situ X-ray diffraction at high pressures and temperatures

    International Nuclear Information System (INIS)

    Tronche, E.J.; Van Kan Parker, M.; De Vries, J.; Wang, Y.; Sanehire, T.; Li, J.; Chen, B.; Gao, L.; Klemme, S.; McCammon, C.A.; Van Westerenen, W.

    2010-01-01

    We present in situ measurements of the unit-cell volume of a natural terrestrial ilmenite (Jagersfontein mine, South Africa) and a synthetic reduced ilmenite (FeTiO 3 ) at simultaneous high pressure and high temperature up to 16 GPa and 1273 K. Unit-cell volumes were determined using energy-dispersive synchrotron X-ray diffraction in a multi-anvil press. Moessbauer analyses show that the synthetic sample contained insignificant amounts of Fe 3+ both before and after the experiment. Results were fit to Birch-Murnaghan thermal equations of state, which reproduce the experimental data to within 0.5 and 0.7 GPa for the synthetic and natural samples, respectively. At ambient conditions, the unit-cell volume of the natural sample (V 0 = 314.75 ± 0.23 (1σ) (angstrom) 3 ) is significantly smaller than that of the synthetic sample (V 0 = 319.12 ± 0.26 (angstrom) 3 ). The difference can be attributed to the presence of impurities and Fe 3+ in the natural sample. The 1 bar isothermal bulk moduli K T0 for the reduced ilmenite is slightly larger than for the natural ilmenite (181 ± 7 and 165 ± 6 GPa, respectively), with pressure derivatives K(prime) 0 = 3 ± 1. Our results, combined with literature data, suggest that the unit-cell volume of reduced ilmenite is significantly larger than that of oxidized ilmenite, whereas their thermoelastic parameters are similar. Our data provide more appropriate input parameters for thermo-chemical models of lunar interior evolution, in which reduced ilmenite plays a critical role.

  5. High-pressure Raman investigation of the semiconductor antimony oxide

    Energy Technology Data Exchange (ETDEWEB)

    Geng, Aihui; Cao, Lihua [State Key Lab on High Power Semiconductor Laser, Changchun University of Science and Technology, 130022 Changchun (China); Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, 130012 Changchun (China); Wan, Chunming [State Key Lab on High Power Semiconductor Laser, Changchun University of Science and Technology, 130022 Changchun (China); Ma, Yanmei [Department of Agronomy, Jilin University, 130062 Changchun (China)

    2011-05-15

    The in situ high-pressure behavior of the semiconductor antimony trioxide (Sb{sub 2}O{sub 3}) has been investigated by Raman spectroscopy techniques in a diamond anvil cell up to 20 GPa at room temperature. New peaks in the external lattice mode range emerged at a pressure above 8.6-15 GPa, suggesting that the structural phase transition occurred. The pressure dependence of Raman frequencies was obtained. The band at 139 cm{sup -1} (assigned to group mode) has a pressure dependence of -0.475 cm{sup -1}/GPa and reveals significant softening at high pressure. (copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  6. The measurement for level of marine high-temperature and high-pressure vessels

    International Nuclear Information System (INIS)

    Lin Jie.

    1986-01-01

    The various error factors in measurement for level of marine high-temperature and high-pressure vessels are anslysed. The measuring method of error self compensation and its simplification for land use are shown

  7. Anisotropic deformation of Zr–2.5Nb pressure tube material at high temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Fong, R.W.L., E-mail: fongr@aecl.ca [Fuel and Fuel Channel Safety Branch, Atomic Energy of Canada Limited, Chalk River Nuclear Laboratories, Chalk River, Ontario (Canada)

    2013-09-15

    Zr–2.5Nb alloy is used for the pressure tubes in CANDU® reactor fuel channels. In reactor, the pressure tube normally operates at 300 °C and experiences a primary coolant fluid internal pressure of approximately 10 MPa. Manufacturing and processing procedures generate an anisotropic state in the pressure tube which makes the tube stronger in the hoop (transverse) direction than in the axial (longitudinal) direction. This anisotropy condition is present for temperatures less than 500 °C. During postulated accident conditions where the material temperature could reach 1000 °C, it might be assumed that the high temperature and subsequent phase change would reduce the inherent anisotropy, and thus affect the deformation behaviour (ballooning) of the pressure tube. From constant-load, rapid-temperature-ramp, uniaxial deformation tests, the deformation rate in the longitudinal direction of the tube behaves differently than the deformation rate in the transverse direction of the tube. This anisotropic mechanical behaviour appears to persist at temperatures up to 1000 °C. This paper presents the results of high-temperature deformation tests using longitudinal and transverse specimens taken from as-received Zr–2.5Nb pressure tubes. It is shown that the anisotropic deformation behaviour observed at high temperatures is largely due to the stable crystallographic texture of the α-Zr phase constituent in the material that was previously observed by neutron diffraction measurements during heating at temperatures up to 1050 °C. The deformation behaviour is also influenced by the phase transformation occurring at high temperatures during heating. The effects of texture and phase transformation on the anisotropic deformation of as-received Zr–2.5Nb pressure tube material are discussed in the context of the tube ballooning behaviour. Because of the high temperatures in postulated accident scenarios, any irradiation damage will be annealed from the pressure tube material

  8. Ammonia oxidation at high pressure and intermediate temperatures

    DEFF Research Database (Denmark)

    Song, Yu; Hashemi, Hamid; Christensen, Jakob Munkholt

    2016-01-01

    Ammonia oxidation experiments were conducted at high pressure (30 bar and 100 bar) under oxidizing and stoichiometric conditions, respectively, and temperatures ranging from 450 to 925 K. The oxidation of ammonia was slow under stoichiometric conditions in the temperature range investigated. Under...... oxidizing conditions the onset temperature for reaction was 850–875 K at 30 bar, while at 100 bar it was about 800 K, with complete consumption of NH3 at 875 K. The products of reaction were N2 and N2O, while NO and NO2 concentrations were below the detection limit even under oxidizing conditions. The data...... was satisfactory. The main oxidation path for NH3 at high pressure under oxidizing conditions is NH3⟶+OH NH2⟶+HO2,NO2 H2NO⟶+O2 HNO⟶+O2 NO ⟶+NH2 N2. The modeling predictions are most sensitive to the reactions NH2 + NO = NNH + OH and NH2 + HO2 = H2NO + OH, which promote the ammonia consumption by forming OH...

  9. Colloquium: High pressure and road to room temperature superconductivity

    Science.gov (United States)

    Gor'kov, Lev P.; Kresin, Vladimir Z.

    2018-01-01

    This Colloquium is concerned with the superconducting state of new high-Tc compounds containing hydrogen ions (hydrides). Recently superconductivity with the record-setting transition temperature of Tc=203 K was reported for sulfur hydrides under high pressure. In general, high pressure serves as a path finding tool toward novel structures, including those with very high Tc . The field has a rich and interesting history. Currently, it is broadly recognized that superconductivity in sulfur hydrides owes its origin to the phonon mechanism. However, the picture differs from the conventional one in important ways. The phonon spectrum in sulfur hydride is both broad and has a complex structure. Superconductivity arises mainly due to strong coupling to the high-frequency optical modes, although the acoustic phonons also make a noticeable contribution. A new approach is described, which generalizes the standard treatment of the phonon mechanism and makes it possible to obtain an analytical expression for Tc in this phase. It turns out that, unlike in the conventional case, the value of the isotope coefficient (for the deuterium-hydrogen substitution) varies with the pressure and reflects the impact of the optical modes. The phase diagram, that is the pressure dependence of Tc , is rather peculiar. A crucial feature is that increasing pressure results in a series of structural transitions, including the one which yields the superconducting phase with the record Tc of 203 K. In a narrow region near P ≈150 GPa the critical temperature rises sharply from Tc≈120 to ≈200 K . It seems that the sharp structural transition, which produces the high-Tc phase, is a first-order phase transition caused by interaction between the order parameter and lattice deformations. A remarkable feature of the electronic spectrum in the high-Tc phase is the appearance of small pockets at the Fermi level. Their presence leads to a two-gap spectrum, which can, in principle, be observed with the

  10. Volatility of coal liquids at high temperatures and pressures

    Energy Technology Data Exchange (ETDEWEB)

    Wilson, G M; Johnston, R H; Hwang, S C; Tsonopoulos, C

    1981-01-01

    The volatility of coal liquids has been experimentally determined at 700-880 F and about 2000 psia. These measurements were made in a flow apparatus to minimize thermal decomposition effects at high temperatures. Three coal liquids in mixture with Hat2, methane, and Hat2S were investigated. Measurements were also made up to 900 F on the vapor pressure of pure compounds found in coal liquids and on the equilibrium pressure of narrow coal liquid cuts. These data were used to develop a new method for the prediction of the critical point and the superatmospheric vapour pressures of aromatic fractions that is superior to the Maxwell-Bonnell correlation. The VLE data on coal liquids and some recent high-temperature VLE data on binaries of aromatics with Hat2 or methane were analyzed with a modified Chao-Seader correlation and a modified Redlich-Kwong equation of state. Both VLE correlations are shown to be equivalent in the prediction of the volatility of coal liquids, when the new vapour pressure procedure is used.

  11. High temperature pressure water's blowdown into water. Experimental results

    International Nuclear Information System (INIS)

    Ishida, Toshihisa; Kusunoki, Tsuyoshi; Kasahara, Yoshiyuki; Iida, Hiromasa

    1994-01-01

    The purpose of the present experimental study is to clarify the phenomena in blowdown of high temperature and pressure water in pressure vessel into the containment water for evaluation of design of an advanced marine reactor(MRX). The water blown into the containment water flushed and formed steam jet plume. The steam jet condensed in the water, but some stream penetrated to gas phase of containment and contributed to increase of containment pressure. (author)

  12. Properties of planetary fluids at high pressure and temperature

    International Nuclear Information System (INIS)

    Nellis, W.J.; Hamilton, D.C.; Holmes, N.C.; Radousky, H.B.; Ree, F.H.; Ross, M.; Young, D.A.; Nicol, M.

    1987-01-01

    In order to derive models of the interiors of Uranus, Neptune, Jupiter and Saturn, researchers studied equations of state and electrical conductivities of molecules at high dynamic pressures and temperatures. Results are given for shock temperature measurements of N 2 and CH 4 . Temperature data allowed demonstration of shock induced cooling in the the transition region and the existence of crossing isotherms in P-V space

  13. 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

  14. In Situ Ambient Pressure X-ray Photoelectron Spectroscopy of Cobalt Perovskite Surfaces under Cathodic Polarization at High Temperatures

    KAUST Repository

    Crumlin, Ethan J.; Mutoro, Eva; Hong, Wesley T.; Biegalski, Michael D.; Christen, Hans M.; Liu, Zhi; Bluhm, Hendrik; Shao-Horn, Yang

    2013-01-01

    Heterostructured oxide interfaces have demonstrated enhanced oxygen reduction reaction rates at elevated temperatures (∼500-800 C); however, the physical origin underlying this enhancement is not well understood. By using synchrotron-based in situ ambient pressure X-ray photoelectron spectroscopy (APXPS), we focus on understanding the surface electronic structure, elemental composition, and chemical nature of epitaxial La0.8Sr 0.2CoO3-δ (LSC113), (La 0.5Sr0.5)2CoO4±δ (LSC214), and LSC214-decorated LSC113 (LSC 113/214) thin films as a function of applied electrical potentials (0 to -800 mV) at 520 C and p(O2) of 1 × 10-3 atm. Shifts in the top of the valence band binding energy and changes in the Sr 3d and O 1s spectral components under applied bias reveal key differences among the film chemistries, most notably in the degree of Sr segregation to the surface and quantity of active oxygen sites in the perovskite termination layer. These differences help to identify important factors governing the enhanced activity of oxygen electrocatalysis observed for the LSC113/214 heterostructured surface. © 2013 American Chemical Society.

  15. In Situ Ambient Pressure X-ray Photoelectron Spectroscopy of Cobalt Perovskite Surfaces under Cathodic Polarization at High Temperatures

    KAUST Repository

    Crumlin, Ethan J.

    2013-08-08

    Heterostructured oxide interfaces have demonstrated enhanced oxygen reduction reaction rates at elevated temperatures (∼500-800 C); however, the physical origin underlying this enhancement is not well understood. By using synchrotron-based in situ ambient pressure X-ray photoelectron spectroscopy (APXPS), we focus on understanding the surface electronic structure, elemental composition, and chemical nature of epitaxial La0.8Sr 0.2CoO3-δ (LSC113), (La 0.5Sr0.5)2CoO4±δ (LSC214), and LSC214-decorated LSC113 (LSC 113/214) thin films as a function of applied electrical potentials (0 to -800 mV) at 520 C and p(O2) of 1 × 10-3 atm. Shifts in the top of the valence band binding energy and changes in the Sr 3d and O 1s spectral components under applied bias reveal key differences among the film chemistries, most notably in the degree of Sr segregation to the surface and quantity of active oxygen sites in the perovskite termination layer. These differences help to identify important factors governing the enhanced activity of oxygen electrocatalysis observed for the LSC113/214 heterostructured surface. © 2013 American Chemical Society.

  16. High Temperature- and High Pressure-Processed Garlic Improves Lipid Profiles in Rats Fed High Cholesterol Diets

    Science.gov (United States)

    Sohn, Chan Wok; Kim, Hyunae; You, Bo Ram; Kim, Min Jee; Kim, Hyo Jin; Lee, Ji Yeon; Sok, Dai-Eun; Kim, Jin Hee; Lee, Kun Jong

    2012-01-01

    Abstract Garlic protects against degenerative diseases such as hyperlipidemia and cardiovascular diseases. However, raw garlic has a strong pungency, which is unpleasant. In this study, we examined the effect of high temperature/high pressure-processed garlic on plasma lipid profiles in rats. Sprague–Dawley rats were fed a normal control diet, a high cholesterol (0.5% cholesterol) diet (HCD) only, or a high cholesterol diet supplemented with 0.5% high temperature/high pressure-processed garlic (HCP) or raw garlic (HCR) for 10 weeks. The body weights of the rats fed the garlic-supplemented diets decreased, mostly because of reduced fat pad weights. Plasma levels of total cholesterol (TC), low-density lipoprotein cholesterol, and triglyceride (TG) in the HCP and HCR groups decreased significantly compared with those in the HCD group. Additionally, fecal TC and TG increased significantly in the HCP and HCR groups. It is notable that no significant differences in plasma or fecal lipid profiles were observed between the HCP and HCR groups. High temperature/high pressure-processed garlic contained a higher amount of S-allyl cysteine than raw garlic (Pgarlic may be useful as a functional food to improve lipid profiles. PMID:22404600

  17. Pressure-induced amorphization and reactivity of solid dimethyl acetylene probed by in situ FTIR and Raman spectroscopy

    Science.gov (United States)

    Guan, Jiwen; Daljeet, Roshan; Kieran, Arielle; Song, Yang

    2018-06-01

    Conjugated polymers are prominent semiconductors that have unique electric conductivity and photoluminescence. Synthesis of conjugated polymers under high pressure is extremely appealing because it does not require a catalyst or solvent used in conventional chemical methods. Transformation of acetylene and many of its derivatives to conjugated polymers using high pressure has been successfully achieved, but not with dimethyl acetylene (DMA). In this work, we present a high-pressure study on solid DMA using a diamond anvil cell up to 24.4 GPa at room temperature characterized by in situ Fourier transform infrared and Raman spectroscopy. Our results show that solid DMA exists in a phase II crystal structure and is stable up to 12 GPa. Above this pressure, amorphization was initiated and the process was completed at 24.4 GPa. The expected polymeric transformation was not evident upon compression, but only observed upon decompression from a threshold compression pressure (e.g. 14.4 GPa). In situ florescence measurements suggest excimer formation via crystal defects, which induces the chemical reactions. The vibrational spectral analysis suggests the products contain the amorphous poly(DMA) and possibly additional amorphous hydrogenated carbon material.

  18. Structural stability of the smectite-doped lanthanum under high pressures and high temperatures

    International Nuclear Information System (INIS)

    Stefani, Vicente Fiorini

    2012-01-01

    Smectites are phyllosilicates that have a tetrahedron: octahedron structure ratio of 2:1, with high cation exchange capacity (CEC) in the interlayers. For these and other features, smectites have been used in many parts of the world as secondary barriers with the goal of containing a possible leak of radioactive elements in final disposal facilities for radioactive waste through cation exchange. Our aim in this work is to reach the cation exchange in calcium montmorillonite (smectite dioctahedral) by lanthanum to simulate trivalent radionuclides and to study the stability of this structure under high pressure and high temperature. To achieve high pressure it was used two different technique: DAC (Diamond Anvil Cell), achieving pressures up to 12GPa at room temperature and hydraulic press with a toroidal chamber profile to achieve pressures up to 7,7GPa and temperatures up to 900 degree C. The heating is achieved simultaneously by an electric system coupled in the hydraulic press. The outcomes show that the smectite structure doped with lanthanum remains stable under 12GPa at room temperature and 2.5GPa at 200 degree C. However, above 300 degree C at 2.5GPa the structure becomes a new phase of muscovite-like, rich of La, where it loses its interlayer water and turns out to be irreversible. Furthermore, it is important to point out that the higher temperature the better ordered is the structure and it is still stable under 7.7GPa and 900 degree C. Moreover, after all experiments the structure continues being dioctahedral. The new phase of muscovite-like, rich of La, in contact with a calcium solution remains partially unchanged, whereas the other part returns to the original structure (montmorillonite-Ca). The following analyses were performed: X-ray diffraction (XRD) for evaluating the spatial structure; Fourier transform infrared spectroscopy (FTIR) for getting information about the vibrational modes; scanning electron microscopy with dispersive Xray spectroscopy

  19. Analysis of pressure drop accidents in high temperature gas-cooled reactors

    International Nuclear Information System (INIS)

    Kameoka, Toshiyuki

    1980-01-01

    Research and development are carried out on various problems in order to realize a multi-purpose, high temperature gas-cooled experimental reactor by Japan Atomic Energy Research Institute and others. In the experimental reactor in consideration at present, it is planned to flow helium at 1000 deg C and 40 atm. For the purpose, high temperature heat insulation structures are designed and developed, which insulate heat on the internal surfaces of pressure vessels and pipings. Consideration must be given to these internal heat insulation structures about the various characteristics in the working environmental temperature and pressure conditions, the measures for preventing the by-pass flow due to the formation of gaps and the abnormal leak of heat through the natural convection in the heat insulators and others. In this paper, the experimental results on the rapid pressure reduction characteristics of ceramic fiber heat insulation structures are reported. The ceramic fiber heat insulation structures have the features such as the application to uneven surfaces and penetration parts, the prevention of by-pass flow, and very low permeability. The problem is the restoring force after the high temperature compression. The experiment on rapid pressure reduction due to the accidental release of gas and the results are reported. (Kako, I.)

  20. Synthesis and stability of hydrogen selenide compounds at high pressure

    Energy Technology Data Exchange (ETDEWEB)

    Pace, Edward J.; Binns, Jack; Alvarez, Miriam Pena; Dalladay-Simpson, Philip; Gregoryanz, Eugene; Howie, Ross T. (Edinburgh); (CHPSTAR- China)

    2017-11-14

    The observation of high-temperature superconductivity in hydride sulfide (H2S) at high pressures has generated considerable interest in compressed hydrogen-rich compounds. High-pressure hydrogen selenide (H2Se) has also been predicted to be superconducting at high temperatures; however, its behaviour and stability upon compression remains unknown. In this study, we synthesize H2Se in situ from elemental Se and molecular H2 at pressures of 0.4 GPa and temperatures of 473 K. On compression at 300 K, we observe the high-pressure solid phase sequence (I-I'-IV) of H2Se through Raman spectroscopy and x-ray diffraction measurements, before dissociation into its constituent elements. Through the compression of H2Se in H2 media, we also observe the formation of a host-guest structure, (H2Se)2H2, which is stable at the same conditions as H2Se, with respect to decomposition. These measurements show that the behaviour of H2Se is remarkably similar to that of H2S and provides further understanding of the hydrogen chalcogenides under pressure.

  1. Highly Sensitive Reentrant Cavity-Microstrip Patch Antenna Integrated Wireless Passive Pressure Sensor for High Temperature Applications

    Directory of Open Access Journals (Sweden)

    Fei Lu

    2017-01-01

    Full Text Available A novel reentrant cavity-microstrip patch antenna integrated wireless passive pressure sensor was proposed in this paper for high temperature applications. The reentrant cavity was analyzed from aspects of distributed model and equivalent lumped circuit model, on the basis of which an optimal sensor structure integrated with a rectangular microstrip patch antenna was proposed to better transmit/receive wireless signals. In this paper, the proposed sensor was fabricated with high temperature resistant alumina ceramic and silver metalization with weld sealing, and it was measured in a hermetic metal tank with nitrogen pressure loading. It was verified that the sensor was highly sensitive, keeping stable performance up to 300 kPa with an average sensitivity of 981.8 kHz/kPa at temperature 25°C, while, for high temperature measurement, the sensor can operate properly under pressure of 60–120 kPa in the temperature range of 25–300°C with maximum pressure sensitivity of 179.2 kHz/kPa. In practical application, the proposed sensor is used in a method called table lookup with a maximum error of 5.78%.

  2. High pressure and temperature induced structural and elastic properties of lutetium chalcogenides

    Science.gov (United States)

    Shriya, S.; Kinge, R.; Khenata, R.; Varshney, Dinesh

    2018-04-01

    The high-pressure structural phase transition and pressure as well temperature induced elastic properties of rock salt to CsCl structures in semiconducting LuX (X = S, Se, and Te) chalcogenides compound have been performed using effective interionic interaction potential with emphasis on charge transfer interactions and covalent contribution. Estimated values of phase transition pressure and the volume discontinuity in pressure-volume phase diagram indicate the structural phase transition from ZnS to NaCl structure. From the investigations of elastic constants the pressure (temperature) dependent volume collapse/expansion, melting temperature TM, Hardness (HV), and young modulus (E) the LuX lattice infers mechanical stiffening, and thermal softening.

  3. Propane Oxidation at High Pressure and Intermediate Temperatures

    DEFF Research Database (Denmark)

    Hashemi, Hamid; Christensen, Jakob Munkholt; Glarborg, Peter

    Propane oxidation at intermediate temperatures (500—900 K) and high pressure (100 bar) has been characterized by conducting experiments in a laminar flow reactor over a wide range of stoichiometries. The onset of fuel oxidation was found to be 600—725 K, depending on mixture stoichiometry...

  4. Large inelastic deformation analysis of steel pressure vessels at high temperature

    International Nuclear Information System (INIS)

    Ikonen, K.

    2001-01-01

    This publication describes the calculation methodology developed for a large inelastic deformation analysis of pressure vessels at high temperature. Continuum mechanical formulation related to a large deformation analysis is presented. Application of the constitutive equations is simplified when the evolution of stress and deformation state of an infinitesimal material element is considered in the directions of principal strains determined by the deformation during a finite time increment. A quantitative modelling of time dependent inelastic deformation is applied for reactor pressure vessel steels. Experimental data of uniaxial tensile, relaxation and creep tests performed at different laboratories for reactor pressure vessel steels are investigated and processed. An inelastic deformation rate model of strain hardening type is adopted. The model simulates well the axial tensile, relaxation and creep tests from room temperature to high temperature with only a few fitting parameters. The measurement data refined for the inelastic deformation rate model show useful information about inelastic deformation phenomena of reactor pressure vessel steels over a wide temperature range. The methodology and calculation process are validated by comparing the calculated results with measurements from experiments on small scale pressure vessels. A reasonably good agreement, when taking several uncertainties into account, is obtained between the measured and calculated results concerning deformation rate and failure location. (orig.)

  5. Design and Fabrication of a Piezoresistive Pressure Sensor for Ultra High Temperature Environment

    International Nuclear Information System (INIS)

    Zhao, L B; Zhao, Y L; Jiang, Z D

    2006-01-01

    In order to solve the pressure measurement problem in the harsh environment, a piezoresistive pressure sensor has been developed, which can be used under high temperature above 200 deg. C and is able to endure instantaneous ultra high temperature (2000deg. C, duration≤2s) impact. Based on the MEMS (Micro Electro-Mechanical System) and integrated circuit technology, the piezoresistive pressure sensor's sensitive element was fabricated and constituted by silicon substrate, a thin buried silicon dioxide layer, four p-type resistors in the measuring circuit layer by boron ion implantation and photolithography, the top SiO2 layer by oxidation, stress matching Si3N4 layer, and a Ti-Pt-Au beam lead layer for connecting p-type resistors by sputtering. In order to decrease the leak-current influence to sensor in high temperature above 200deg. C, the buried SiO2 layer with the thickness 367 nm was fabricated by the SIMOX (Separation by Implantation of Oxygen) technology, which was instead of p-n junction to isolate the upper measuring circuit layer from Si substrate. In order to endure instantaneous ultra high temperature impact, the mechanical structure with cantilever and diaphragm and transmitting beam was designed. By laser welding and high temperature packaging technology, the high temperature piezoresistive pressure sensor was fabricated with range of 120MPa. After the thermal compensation, the sensor's thermal zero drift k 0 and thermal sensitivity drift k s were easy to be less than 3x10 -4 FS/deg. C. The experimental results show that the developed piezoresistive pressure sensor has good performances under high temperature and is able to endure instantaneous ultra high temperature impact, which meets the requirements of modern industry, such as aviation, oil, engine, etc

  6. Iterative Boltzmann plot method for temperature and pressure determination in a xenon high pressure discharge lamp

    Energy Technology Data Exchange (ETDEWEB)

    Zalach, J.; Franke, St. [INP Greifswald, Felix-Hausdorff-Str. 2, 17489 Greifswald (Germany)

    2013-01-28

    The Boltzmann plot method allows to calculate plasma temperatures and pressures if absolutely calibrated emission coefficients of spectral lines are available. However, xenon arcs are not very well suited to be analyzed this way, as there are only a limited number of lines with atomic data available. These lines have high excitation energies in a small interval between 9.8 and 11.5 eV. Uncertainties in the experimental method and in the atomic data further limit the accuracy of the evaluation procedure. This may result in implausible values of temperature and pressure with inadmissible uncertainty. To omit these shortcomings, an iterative scheme is proposed that is making use of additional information about the xenon fill pressure. This method is proved to be robust against noisy data and significantly reduces the uncertainties. Intentionally distorted synthetic data are used to illustrate the performance of the method, and measurements performed on a laboratory xenon high pressure discharge lamp are analyzed resulting in reasonable temperatures and pressures with significantly reduced uncertainties.

  7. High-temperature, high-pressure bonding of nested tubular metallic components

    International Nuclear Information System (INIS)

    Quinby, T.C.

    1980-01-01

    This invention is a tool for effecting high-temperature, high compression bonding between the confronting faces of nested, tubular, metallic components. In a typical application, the tool is used to produce tubular target assemblies for irradiation in nuclear reactors or particle accelerators, the target assembly comprising a uranium foil and an aluminum-alloy substrate. The tool preferably is composed throughout of graphite. It comprises a tubular restraining member in which a mechanically expandable tubular core is mounted to form an annulus with the member. The components to be bonded are mounted in nested relation in the annulus. The expandable core is formed of individually movable, axially elongated segments whose outer faces cooperatively define a cylindrical pressing surface and whose inner faces cooperatively define two opposed, inwardly tapered, axial bores. Tapered rams extend respectively into the bores. The loaded tool is mounted in a conventional hot-press provided with evacuation means, heaters for maintaining its interior at bonding temperature, and hydraulic cylinders for maintaining a selected inwardly directed pressure on the tapered rams. With the hotpress evacuated and the loaded tool at the desired temperature, the cylinders are actuated to apply the selected pressure to the rams. The rams in turn expand the segmented core to maintain the nested components in compression against the restraining member. These conditions are maintained until the confronting faces of the nested components are joined in a continuous, uniform bond characterized by high thermal conductivity

  8. High-temperature, high-pressure bonding of nested tubular metallic components

    Science.gov (United States)

    Quinby, T.C.

    A tool is described for effecting high-temperature, high-compression bonding between the confronting faces of nested, tubular, metallic components. In a typical application, the tool is used to produce tubular target assemblies for irradiation in nuclear reactors or particle accelerators. The target assembly comprising a uranum foil and an aluninum-alloy substrate. The tool is composed of graphite. It comprises a tubular restraining member in which a mechanically expandable tubular core is mounted to form an annulus. The components to be bonded are mounted in nested relation in the annulus. The expandable core is formed of individually movable, axially elongated segments whose outer faces cooperatively define a cylindrical pressing surface and whose inner faces cooperatively define two opposed, inwardly tapered, axial bores. Tapered rams extend into the bores. The loaded tool is mounted in a conventional hot-press provided with evacuation means, heaters for maintaining its interior at bonding temperature, and hydraulic cylinders for maintaining a selected inwardly directed pressure on the tapered rams. With the hot-press evacuated and the loaded tool at the desired temperature, the cylinders are actuated to apply the selected pressure to the rams. The rams in turn expand the segmented core to maintain the nested components in compression against the restraining member. These conditions are maintained until the confronting faces of the nested components are joined in a continuous, uniform bond characterized by high thermal conductivity.

  9. MEMS fiber-optic Fabry-Perot pressure sensor for high temperature application

    Science.gov (United States)

    Fang, G. C.; Jia, P. G.; Cao, Q.; Xiong, J. J.

    2016-10-01

    We design and demonstrate a fiber-optic Fabry-Perot pressure sensor (FOFPPS) for high-temperature sensing by employing micro-electro-mechanical system (MEMS) technology. The FOFPPS is fabricated by anodically bonding the silicon wafer and the Pyrex glass together and fixing the facet of the optical fiber in parallel with the silicon surface by glass frit and organic adhesive. The silicon wafer can be reduced through dry etching technology to construct the sensitive diaphragm. The length of the cavity changes with the deformation of the diaphragm due to the loaded pressure, which leads to a wavelength shift of the interference spectrum. The pressure can be gauged by measuring the wavelength shift. The pressure experimental results show that the sensor has linear pressure sensitivities ranging from 0 kPa to 600 kPa at temperature range between 20°C to 300°C. The pressure sensitivity at 300°C is approximately 27.63 pm/kPa. The pressure sensitivities gradually decrease with increasing the temperature. The sensor also has a linear thermal drift when temperature changes from 20°C - 300°C.

  10. A system for incubations at high gas partial pressure

    Directory of Open Access Journals (Sweden)

    Patrick eSauer

    2012-02-01

    Full Text Available High-pressure is a key feature of deep subsurface environments. High partial pressure of dissolved gasses plays an important role in microbial metabolism, because thermodynamic feasibility of many reactions depends on the concentration of reactants. For gases, this is controlled by their partial pressure, which can exceed one MPa at in-situ conditions. Therefore, high hydrostatic pressure alone is not sufficient to recreate true deep subsurface in-situ conditions, but the partial pressure of dissolved gasses has to be controlled as well.We developed an incubation system that allows for incubations at hydrostatic pressure up to 60 MPa, temperatures up to 120° C and at high gas partial pressure. The composition and partial pressure of gasses can be manipulated during the experiment. The system is mainly made from off-the-shelf components with only very few custom-made parts. A flexible and inert PVDF incubator sleeve, which is almost impermeable for gases, holds the sample and separates it from the pressure fluid. The flexibility of the incubator sleeve allows for sub-sampling of the medium without loss of pressure. Experiments can be run in both static and flow through mode. The incubation system described here is usable for versatile purposes, not only the incubation of microorganisms and determination of growth rates, but also for chemical degradation or extraction experiments under high gas saturation, e.g. fluid-gas-rock-interactions in relation to carbon dioxide sequestration.As an application of the system we extracted organic acids from sub-bituminous coal using H2O as well as a H2O-CO2 mixture at elevated temperature (90°C and pressure (5 MPa. Subsamples were taken during the incubation and analysed by ion chromatography. Furthermore we demonstrated the applicability of the system for studies of microbial activity, using samples from the Isis mud volcano. We could detect an increase in sulphate reduction rate upon the addition of

  11. Wireless contactless pressure measurement of an LC passive pressure sensor with a novel antenna for high-temperature applications

    Science.gov (United States)

    Li, Chen; Tan, Qiu-Lin; Xue, Chen-Yang; Zhang, Wen-Dong; Li, Yun-Zhi; Xiong, Ji-Jun

    2015-04-01

    In this paper, a novel antenna is proposed for high-temperature testing, which can make the high-temperature pressure characteristics of a wireless passive ceramic pressure sensor demonstrated at up to a temperature of 600 °C. The design parameters of the antenna are similar to those of the sensor, which will increase the coupling strength between the sensor and testing antenna. The antenna is fabricated in thick film integrated technology, and the properties of the alumina ceramic and silver ensure the feasibility of the antenna in high-temperature environments. The sensor, coupled with the ceramic antenna, is investigated using a high-temperature pressure testing platform. The experimental measurement results show that the pressure signal in a harsh environment can be detected by the frequency diversity of the sensor. Project supported by the National Natural Science Foundation for Distinguished Young Scholars, China (Grant No. 51425505), the National Natural Science Foundation of China (Grant No. 61471324), the Program for the Outstanding Innovative Teams of Higher Learning Institutions of Shanxi Province, China (Grant No. 2013-077), and the Graduate Students Outstanding Innovation Project of Shanxi Province, China (Grant No. 20143020).

  12. Thermodynamic functions and vapor pressures of uranium and plutonium oxides at high temperatures

    International Nuclear Information System (INIS)

    Green, D.W.; Reedy, G.T.; Leibowitz, L.

    1977-01-01

    The total energy release in a hypothetical reactor accident is sensitive to the total vapor pressure of the fuel. Thermodynamic functions which are accurate at high temperature can be calculated with the methods of statistical mechanics provided that needed spectroscopic data are available. This method of obtaining high-temperature vapor pressures should be greatly superior to the extrapolation of experimental vapor pressure measurements beyond the temperature range studied. Spectroscopic data needed for these calculations are obtained from infrared spectroscopy of matrix-isolated uranium and plutonium oxides. These data allow the assignments of the observed spectra to specific molecular species as well as the calculation of anharmonicities for monoxides, bond angles for dioxides, and molecular geometries for trioxides. These data are then employed, in combination with data on rotational and electronic molecular energy levels, to determine thermodynamic functions that are suitable for the calculation of high-temperature vapor pressures

  13. Study of CT Scan Flooding System at High Temperature and Pressure

    Science.gov (United States)

    Chen, X. Y.

    2017-12-01

    CT scan flooding experiment can scan micro-pore in different flooding stages by the use of CT scan technology, without changing the external morphology and internal structure of the core, and observe the distribution characterization in pore medium of different flooding fluid under different pressure.thus,it can rebuilt the distribution images of oil-water distribution in different flooding stages. However,under extreme high pressure and temperature conditions,the CT scan system can not meet the requirements. Container of low density materials or thin shell can not resist high pressure,while high density materials or thick shell will cause attenuation and scattering of X-ray. The experiment uses a simple Ct scanning systems.X ray from a point light source passing trough a micro beryllium shell on High pressure stainless steal container,continuously irradiates the core holder that can continuously 360° rotate along the core axis. A rare earth intensifying screen behind the core holder emitting light when irradiated with X ray can show the core X ray section image. An optical camera record the core X ray images through a transparency high pressure glazing that placed on the High pressure stainless steal container.Thus,multiple core X ray section images can reconstruct the 3D core reconstruction after a series of data processing.The experiment shows that both the micro beryllium shell and rare earth intensifying screen can work in high temperature and high pressure environment in the stainless steal container. This way that X-ray passes through a thin layer of micro beryllium shell , not high pressure stainless steal shell,avoid the attenuation and scattering of X-ray from the container shell,while improving the high-pressure experiment requirements.

  14. Defects of diamond single crystal grown under high temperature and high pressure

    Energy Technology Data Exchange (ETDEWEB)

    Su, Qingcai, E-mail: suqc@sdu.edu.cn [Key Laboratory of Liquid Structure and Heredity of Materials (Ministry of Education), Shandong University, Jinan, P. R. China, 250061 (China); School of Materials Science and Engineering, Shandong University, Jinan, P. R. China, 250061 (China); Shandong Engineering Research Center for Superhard Materials, Zoucheng, P. R. China 273500 (China); Zhang, Jianhua [School of Mechanical Engineering, Shandong University, Jinan, P. R. China, 250061 (China); Li, Musen [Key Laboratory of Liquid Structure and Heredity of Materials (Ministry of Education), Shandong University, Jinan, P. R. China, 250061 (China); School of Materials Science and Engineering, Shandong University, Jinan, P. R. China, 250061 (China); Shandong Engineering Research Center for Superhard Materials, Zoucheng, P. R. China 273500 (China)

    2013-11-01

    The diamond single crystal, synthesized with Fe–Ni–C–B system of catalyst under high temperature and high pressure, had been observed by field emission scanning electron microscope and transmission electron microscope. The presence of a cellular structure suggested that the diamond grew from melted catalyst solution and there existed a zone of component supercooling zone in front of the solid–liquid interface. The main impurities in the diamond crystal was (FeNi){sub 23}C{sub 6}. The triangle screw pit revealed on the (111) plane was generated by the screw dislocation meeting the diamond (111) plane at the points of emergence of dislocations. A narrow twin plane was formed between the two (111) plane. - Highlights: • High pressure, high temperature synthesis of diamond single crystal. • Fe–Ni–C–B used as catalyst, graphite as carbon source. • The main impurity in the diamond crystal was (FeNi){sub 23}C{sub 6}. • Surface defects arose from screw dislocations and stacking faults.

  15. Advanced Packaging Technology Used in Fabricating a High-Temperature Silicon Carbide Pressure Sensor

    Science.gov (United States)

    Beheim, Glenn M.

    2003-01-01

    The development of new aircraft engines requires the measurement of pressures in hot areas such as the combustor and the final stages of the compressor. The needs of the aircraft engine industry are not fully met by commercially available high-temperature pressure sensors, which are fabricated using silicon. Kulite Semiconductor Products and the NASA Glenn Research Center have been working together to develop silicon carbide (SiC) pressure sensors for use at high temperatures. At temperatures above 850 F, silicon begins to lose its nearly ideal elastic properties, so the output of a silicon pressure sensor will drift. SiC, however, maintains its nearly ideal mechanical properties to extremely high temperatures. Given a suitable sensor material, a key to the development of a practical high-temperature pressure sensor is the package. A SiC pressure sensor capable of operating at 930 F was fabricated using a newly developed package. The durability of this sensor was demonstrated in an on-engine test. The SiC pressure sensor uses a SiC diaphragm, which is fabricated using deep reactive ion etching. SiC strain gauges on the surface of the diaphragm sense the pressure difference across the diaphragm. Conventionally, the SiC chip is mounted to the package with the strain gauges outward, which exposes the sensitive metal contacts on the chip to the hostile measurement environment. In the new Kulite leadless package, the SiC chip is flipped over so that the metal contacts are protected from oxidation by a hermetic seal around the perimeter of the chip. In the leadless package, a conductive glass provides the electrical connection between the pins of the package and the chip, which eliminates the fragile gold wires used previously. The durability of the leadless SiC pressure sensor was demonstrated when two 930 F sensors were tested in the combustor of a Pratt & Whitney PW4000 series engine. Since the gas temperatures in these locations reach 1200 to 1300 F, the sensors were

  16. Microwave measurements of water vapor partial pressure at high temperatures

    International Nuclear Information System (INIS)

    Latorre, V.R.

    1991-01-01

    One of the desired parameters in the Yucca Mountain Project is the capillary pressure of the rock comprising the repository. This parameter is related to the partial pressure of water vapor in the air when in equilibrium with the rock mass. Although there are a number of devices that will measure the relative humidity (directly related to the water vapor partial pressure), they generally will fail at temperatures on the order of 150C. Since thee author has observed borehole temperatures considerably in excess of this value in G-Tunnel at the Nevada Test Site (NTS), a different scheme is required to obtain the desired partial pressure data at higher temperatures. This chapter presents a microwave technique that has been developed to measure water vapor partial pressure in boreholes at temperatures up to 250C. The heart of the system is a microwave coaxial resonator whose resonant frequency is inversely proportional to the square root of the real part of the complex dielectric constant of the medium (air) filling the resonator. The real part of the dielectric constant of air is approximately equal to the square of the refractive index which, in turn, is proportional to the partial pressure of the water vapor in the air. Thus, a microwave resonant cavity can be used to measure changes in the relative humidity or partial pressure of water vapor in the air. Since this type of device is constructed of metal, it is able to withstand very high temperatures. The actual limitation is the temperature limit of the dielectric material in the cable connecting the resonator to its driving and monitoring equipment-an automatic network analyzer in our case. In the following sections, the theory of operation, design, construction, calibration and installation of the microwave diagnostics system is presented. The results and conclusions are also presented, along with suggestions for future work

  17. A high-temperature, high-pressure, silver-silver chloride reference electrode

    International Nuclear Information System (INIS)

    King, F.; Bailey, M.G.; Clarke, C.F.; Ikeda, B.M.; Litke, C.D.; Ryan, S.R.

    1989-05-01

    A high-temperature, high-pressure, silver-silver chloride reference electrode is described. This report is meant to serve as a user's guide to the experimentalist. Consequently, the design and construction of the electrode are dealt with in some detail. The problems that may be encountered, along with their possible causes and remedies, are also discussed. Conversion factors are given for both internal and external reference electrodes, so that measured potentials can be related to the standard hydrogen electrode scale

  18. 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)

  19. Experimental Spectroscopic Studies of Carbon Monoxide (CO) Fluorescence at High Temperatures and Pressures.

    Science.gov (United States)

    Carrivain, Olivier; Orain, Mikael; Dorval, Nelly; Morin, Celine; Legros, Guillaume

    2017-10-01

    Two-photon excitation laser-induced fluorescence of carbon monoxide (CO-LIF) is investigated experimentally in order to determine the applicability of this technique for imaging CO concentration in aeronautical combustors. Experiments are carried out in a high temperature, high-pressure test cell, and in a laminar premixed CH 4 /air flame. Influence of temperature and pressure on CO-LIF spectra intensity and shape is reported. The experimental results show that as pressure increases, the CO-LIF excitation spectrum becomes asymmetric. Additionally, the spectrum strongly shifts to the red with a quadratic dependence of the collisional shift upon pressure, which is different from the classical behavior where the collisional shift is proportional to pressure. Moreover, pressure line broadening cannot be reproduced by a Lorenztian profile in the temperature range investigated here (300-1750 K) and, therefore, an alternative line shape is suggested.

  20. Creep of Posidonia Shale at Elevated Pressure and Temperature

    Science.gov (United States)

    Rybacki, E.; Herrmann, J.; Wirth, R.; Dresen, G.

    2017-12-01

    The economic production of gas and oil from shales requires repeated hydraulic fracturing operations to stimulate these tight reservoir rocks. Besides simple depletion, the often observed decay of production rate with time may arise from creep-induced fracture closure. We examined experimentally the creep behavior of an immature carbonate-rich Posidonia shale, subjected to constant stress conditions at temperatures between 50 and 200 °C and confining pressures of 50-200 MPa, simulating elevated in situ depth conditions. Samples showed transient creep in the semibrittle regime with high deformation rates at high differential stress, high temperature and low confinement. Strain was mainly accommodated by deformation of the weak organic matter and phyllosilicates and by pore space reduction. The primary decelerating creep phase observed at relatively low stress can be described by an empirical power law relation between strain and time, where the fitted parameters vary with temperature, pressure and stress. Our results suggest that healing of hydraulic fractures at low stresses by creep-induced proppant embedment is unlikely within a creep period of several years. At higher differential stress, as may be expected in situ at contact areas due to stress concentrations, the shale showed secondary creep, followed by tertiary creep until failure. In this regime, microcrack propagation and coalescence may be assisted by stress corrosion. Secondary creep rates were also described by a power law, predicting faster fracture closure rates than for primary creep, likely contributing to production rate decline. Comparison of our data with published primary creep data on other shales suggests that the long-term creep behavior of shales can be correlated with their brittleness estimated from composition. Low creep strain is supported by a high fraction of strong minerals that can build up a load-bearing framework.

  1. Design and evaluation of a pressure sensor for high temperature nuclear application

    International Nuclear Information System (INIS)

    Yancey, M.E.

    1981-11-01

    The goal of this technical development task was the development of a small eddy-current pressure sensor for use within a high temperature nuclear environment. The sensor is designed for use at pressures and temperatures of up to 17.23 MPa and 650 0 F. The design of the sensor incorporated features to minimize possible errors due to temperature transients present in nuclear applications. This report describes a prototype pressure sensor that was designed, the associated 100 kHz signal conditioning electronics, and the evaluation tests which were conducted

  2. Equilibrium triple point pressure and pressure-temperature phase diagram of polyethylene

    NARCIS (Netherlands)

    Hikosaka, M.; Tsukijima, K.; Rastogi, S.; Keller, A.

    1992-01-01

    The equil. triple point and pressure and temp. phase diagrams of polyethylene were obtained by in situ optical microscopic and x-ray observations of the melting temp. of hexagonal and orthorhombic isolated extended-chain single crystals at high pressure. The melting temps. of extended-chain crystals

  3. A novel interferometric characterization technique for 3D analyses at high pressures and temperatures

    Science.gov (United States)

    Roshanghias, Ali; Bardong, Jochen; Pulko, Jozef; Binder, Alfred

    2018-04-01

    Advanced optical measurement techniques are always of interest for the characterization of engineered surfaces. When pressure or temperature modules are also incorporated, these techniques will turn into robust and versatile methodologies for various applications such as performance monitoring of devices in service conditions. However, some microelectromechanical systems (MEMS) and MOEMS devices require performance monitoring at their final stage, i.e. enclosed or packaged. That necessitates measurements through a protective liquid, plastic, or glass, whereas the conventional objective lenses are not designed for such media. Correspondingly, in the current study, the development and tailoring of a 3D interferometer as a means for measuring the topography of reflective surfaces under transmissive media is sought. For topography measurements through glass, water and oil, compensation glass plates were designed and incorporated into the Michelson type interferometer objectives. Moreover, a customized chamber set-up featuring an optical access for the observation of the topographical changes at increasing pressure and temperature conditions was constructed and integrated into the apparatus. Conclusively, the in situ monitoring of the elastic deformation of sensing microstructures inside MEMS packages was achieved. These measurements were performed at a defined pressure (0–100 bar) and temperature (25 °C–180 °C).

  4. Non-linear pressure/temperature-dependence of high pressure thermal inactivation of proteolytic Clostridium botulinum type B in foods.

    Directory of Open Access Journals (Sweden)

    Maximilian B Maier

    Full Text Available The effect of high pressure thermal (HPT processing on the inactivation of spores of proteolytic type B Clostridium botulinum TMW 2.357 in four differently composed low-acid foods (green peas with ham, steamed sole, vegetable soup, braised veal was studied in an industrially feasible pressure range and temperatures between 100 and 120°C. Inactivation curves exhibited rapid inactivation during compression and decompression followed by strong tailing effects. The highest inactivation (approx. 6-log cycle reduction was obtained in braised veal at 600 MPa and 110°C after 300 s pressure-holding time. In general, inactivation curves exhibited similar negative exponential shapes, but maximum achievable inactivation levels were lower in foods with higher fat contents. At high treatment temperatures, spore inactivation was more effective at lower pressure levels (300 vs. 600 MPa, which indicates a non-linear pressure/temperature-dependence of the HPT spore inactivation efficiency. A comparison of spore inactivation levels achievable using HPT treatments versus a conventional heat sterilization treatment (121.1°C, 3 min illustrates the potential of combining high pressures and temperatures to replace conventional retorting with the possibility to reduce the process temperature or shorten the processing time. Finally, experiments using varying spore inoculation levels suggested the presence of a resistant fraction comprising approximately 0.01% of a spore population as reason for the pronounced tailing effects in survivor curves. The loss of the high resistance properties upon cultivation indicates that those differences develop during sporulation and are not linked to permanent modifications at the genetic level.

  5. 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.

  6. Anharmonic effective pair potentials of gold under high pressure and high temperature

    CERN Document Server

    Okube, M; Ohtaka, O; Fukui, H; Katayama, Y; Utsumi, W

    2002-01-01

    In order to examine the effect of pressure on the anharmonicity of Au, extended x-ray absorption fine-structure spectra near the Au L sub 3 edge were measured in the temperature range from 300 to 1100 K under pressures up to 14 GPa using large-volume high-pressure devices and synchrotron radiation. The anharmonic effective pair potentials of Au, V (u) = au sup 2 + bu sup 3 , at 0.1 MPa, 6 and 14 GPa have been calculated. The pressure dependence of the thermal expansion coefficients has also been evaluated. The reliability of the anharmonic correction proposed on the basis of the Anderson scale has been discussed.

  7. High-Pressure-High-Temperature Processing Reduces Maillard Reaction and Viscosity in Whey Protein-Sugar Solutions

    NARCIS (Netherlands)

    Avila Ruiz, Geraldine; Xi, Bingyan; Minor, Marcel; Sala, Guido; Boekel, van Tiny; Fogliano, Vincenzo; Stieger, Markus

    2016-01-01

    The aim of the study was to determine the influence of pressure in high-pressure-high-temperature (HPHT) processing on Maillard reactions and protein aggregation of whey protein-sugar solutions. Solutions of whey protein isolate containing either glucose or trehalose at pH 6, 7, and 9 were

  8. Energetic materials under high pressures and temperatures: stability, polymorphism and decomposition of RDX

    International Nuclear Information System (INIS)

    Dreger, Z A

    2012-01-01

    A recent progress in understanding the response of energetic crystal of cyclotrimethylene trinitramine (RDX) to high pressures and temperatures is summarized. The optical spectroscopy and imaging studies under static compression and high temperatures provided new insight into phase diagram, polymorphism and decomposition mechanisms at pressures and temperatures relevant to those under shock compression. These results have been used to aid the understanding of processes under shock compression, including the shock-induced phase transition and identification of the crystal phase at decomposition. This work demonstrates that studies under static compression and high temperatures provide important complementary route for elucidating the physical and chemical processes in shocked energetic crystals.

  9. Fabrication of High Temperature and High Pressure Vessel for the Fuel Test

    International Nuclear Information System (INIS)

    Park, Kook Nam; Lee, Jong Min; Sim, Bong Shick; Shon, Jae Min; Ahn, Seung Ho; Yoo, Seong Yeon

    2007-01-01

    The Fuel Test Loop(FTL) which is capable of an irradiation testing under a similar operating condition to those of PWR and CANDU nuclear power plants has been developed and installed in HANARO, KAERI. It is consisted of In-Pile Section(IPS) and Out-of Pile System(OPS). The IPS which is located inside the pool is divided into 3-parts; they are in-pool pipes, IVA(IPS Vessel Assembly) and the support structures. The test fuel is loaded inside a double wall, inner pressure vessel and outer pressure vessel, to keep the functionality of the reactor coolant pressure boundary. The localization of the IVA is achieved by manufacturing through local company and the functional test and verification were done through pressure drop, vibration, hydraulic and leakage tests. The brazing technique of the instrument lines has been checked for its functionality and yield. A IVA has been manufactured by local technique and will be finally tested under out of the high temperature and high pressure test

  10. Pipe connection for high pressure and temperature loads

    International Nuclear Information System (INIS)

    Haferkamp, D.; Hodzic, A.; Paetz, E.; Stach, H.

    1976-01-01

    The patent proposes an inprovement of the clamping device for a pipe joint connecting pipelines which are subject to high pressure and temperature loads, e.g. in a nuclear power plant. This clamping device may be tightened and loosened by remote control. The proposed clamping ring consists of several segments connected with each other by hinge-type guide pins and fishplates. (UWI) [de

  11. Analysis of the structural stability of the smectite submitted to high pressures and temperatures; Analise da estabilidade estrutural da esmectita sob altas pressoes e altas temperaturas

    Energy Technology Data Exchange (ETDEWEB)

    Alabarse, Frederico Gil

    2009-10-15

    The thermal stability of bentonite is of particular interest for containment barrier in nuclear waste disposal facilities. However, very little is known about the stability of smectite (principal component of bentonite) under high-pressure and high-temperature conditions (HPHT). The objective of this work was to investigate the stability of the smectite structure under HP-HT conditions. The HP-HT experiments were performed on toroidal chambers (TC) with pressure up 7.7 GPa and temperatures of 1000 deg C. The samples were characterized by X-ray diffraction after the HP-HT processing. Furthermore, one sample from the original material was analyzed using Fourier transformed infra-red (FTIR) in situ measurements on a diamond anvil cell (DAC) in experiments up to 12 GPa. The original sample of bentonite, calcium dioctahedral montmorillonite with small fraction of quartz, was characterized by FTIR, XRD, X-ray fluorescence (XRF), scanning electron microscopy (SEM), surface area, thermogravimetric analysis (TGA) and differential thermal analysis (DTA). In the experiment performed using the DAC up to 12 GPa, the FTIR in situ measurements analysis showed that the smectite structure is stable with a reversible deformation in the Si-O bond and that the smectite did not loose water. Experiments performed in TC at 7.7 GPa of pressure and 250 deg C of temperature, during 3.5 h showed, after analysis by XRD and FTIR, that the smectite structure is stable and did not loose water. Experiments performed in TC at 7.7 GPa of pressure and 1000 deg C of temperature, during 3.5 h showed, after analysis by XRD and SEM, the transformation of bentonite to the mineral assemblage: Coesite, Quartz, Kyanite and Pyrope. (author)

  12. Effective like- and unlike-pair interactions at high pressure and high temperature

    International Nuclear Information System (INIS)

    Ree, F.H.; van Thiel, M.

    1991-05-01

    We describe how information on effective interactions of chemical species involving C, O, and N atoms at high pressure and high temperature may be inferred from available shock wave data of NO and CO. Our approach uses a modern statistical mechanical theory and a detailed equation of state (EOS) model for the condensed phases of carbon

  13. Thermoelasticity at High Temperatures and Pressures for Ta

    International Nuclear Information System (INIS)

    Orlikowski, D; Soderlind, P; Moriarty, J A

    2004-01-01

    A new methodology for calculating high temperature and pressure elastic moduli in metals has been developed accounting for both the electron-thermal and ion-thermal contributions. Anharmonic and quasi-harmonic thermoelasticity for bcc tantalum have thereby been calculated and compared as a function of temperature (<12,000 K) and pressure (<10 Mbar). In this approach, the full potential linear muffin-tin orbital (FP-LMTO) method for the cold and electron-thermal contributions is closely coupled with ion-thermal contributions obtained via multi-ion, quantum-based interatomic potentials derived from model generalized pseudopotential theory (MGPT). For the later contributions two separate approaches are used. In one approach, the quasi-harmonic ion-thermal contribution is obtained through a Brillouin zone sum of the strain derivatives of the phonons, and in the other the anharmonic ion-thermal contribution is obtained directly through Monte Carlo (MC) canonical distribution averages of strain derivatives on the multi-ion potentials themselves. The resulting elastic moduli compare well in each method and to available ultrasonic measurements and diamond-anvil-cell compression experiments indicating minimal anharmonic effects in bcc tantalum over the considered pressure range

  14. Double-Sided Laser Heating in Radial Diffraction Geometry for Diamond Anvil Cell Deformation Experiments at Simultaneous High Pressures and Temperatures

    Science.gov (United States)

    Miyagi, L. M.; Kunz, M.; Couper, S.; Lin, F.; Yan, J.; Doran, A.; MacDowell, A. A.

    2017-12-01

    The rheology of rocks and minerals in the Earth's deep interior plays a primary role in controlling large scale geodynamic processes such as mantle convection and slab subduction. Plastic deformation resulting from these processes can lead to texture development and associated seismic anisotropy. If a detailed understanding of the link between deformation and seismic anisotropy is established, observations of seismic anisotropy can be used to understand the dynamic state in the deep Earth. However, performing deformation experiments at lower mantle pressure and temperature conditions are extremely challenging. Thus most deformation studies have been performed either at room temperature and high pressure or at reduced pressures and high temperature. Only a few extraordinary efforts have attained pressures and temperatures relevant to lower mantle. Therefore our ability to interpret observations of lower mantle seismic anisotropy in terms of mantle flow models remains limited. In order to expand the pressure and temperature range available for deformation of deep Earth relevant mineral phases, we have developed a laser heating system for in-situ double-sided heating in radial diffraction geometry at beamline 12.2.2 of the Advanced Light Source of Lawrence Berkeley National Laboratory. This allows texture and lattice strain measurements to be recorded at simultaneous high pressures and temperatures in the diamond anvil cell. This new system is integrated into the newly built axial laser heating system to allow for rapid and reliable transitioning between double-sided laser heating in axial and radial geometries. Transitioning to radial geometry is accomplished by redirecting the laser and imaging paths from 0° and 180° to 90° and 270°. To redirect the 90° path, a motorized periscope mirror pair with an objective lens can be inserted into the downstream axial beam path. The 270° redirection is accomplished by removing the upstream axial objective lens and

  15. Pressurized Recuperator For Heat Recovery In Industrial High Temperature Processes

    Directory of Open Access Journals (Sweden)

    Gil S.

    2015-09-01

    Full Text Available Recuperators and regenerators are important devices for heat recovery systems in technological lines of industrial processes and should have high air preheating temperature, low flow resistance and a long service life. The use of heat recovery systems is particularly important in high-temperature industrial processes (especially in metallurgy where large amounts of thermal energy are lost to the environment. The article presents the process design for a high efficiency recuperator intended to work at high operating parameters: air pressure up to 1.2 MPa and temperature of heating up to 900°C. The results of thermal and gas-dynamic calculations were based on an algorithm developed for determination of the recuperation process parameters. The proposed technical solution of the recuperator and determined recuperation parameters ensure its operation under maximum temperature conditions.

  16. Magnetic and Structural Phase Transitions in Thulium under High Pressures and Low Temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Vohra, Yogesh K.; Tsoi, Georgiy M.; Samudrala, Gopi K. [UAB

    2017-10-01

    The nature of 4f electrons in many rare earth metals and compounds may be broadly characterized as being either "localized" or "itinerant", and is held responsible for a wide range of physical and chemical properties. The pressure variable has a very dramatic effect on the electronic structure of rare earth metals which in turn drives a sequence of structural and magnetic transitions. We have carried out four-probe electrical resistance measurements on rare earth metal Thulium (Tm) under high pressures to 33 GPa and low temperatures to 10 K to monitor the magnetic ordering transition. These studies are complemented by angle dispersive x-ray diffraction studies to monitor crystallographic phase transitions at high pressures and low temperatures. We observe an abrupt increase in magnetic ordering temperature in Tm at a pressure of 17 GPa on phase transition from ambient pressure hcp-phase to α-Sm phase transition. In addition, measured equation of state (EOS) at low temperatures show anomalously low thermal expansion coefficients likely linked to magnetic transitions.

  17. Development of self-powered wireless high temperature electrochemical sensor for in situ corrosion monitoring of coal-fired power plant.

    Science.gov (United States)

    Aung, Naing Naing; Crowe, Edward; Liu, Xingbo

    2015-03-01

    Reliable wireless high temperature electrochemical sensor technology is needed to provide in situ corrosion information for optimal predictive maintenance to ensure a high level of operational effectiveness under the harsh conditions present in coal-fired power generation systems. This research highlights the effectiveness of our novel high temperature electrochemical sensor for in situ coal ash hot corrosion monitoring in combination with the application of wireless communication and an energy harvesting thermoelectric generator (TEG). This self-powered sensor demonstrates the successful wireless transmission of both corrosion potential and corrosion current signals to a simulated control room environment. Copyright © 2014 ISA. All rights reserved.

  18. Analysis of fatigue reliability for high temperature and high pressure multi-stage decompression control valve

    Science.gov (United States)

    Yu, Long; Xu, Juanjuan; Zhang, Lifang; Xu, Xiaogang

    2018-03-01

    Based on stress-strength interference theory to establish the reliability mathematical model for high temperature and high pressure multi-stage decompression control valve (HMDCV), and introduced to the temperature correction coefficient for revising material fatigue limit at high temperature. Reliability of key dangerous components and fatigue sensitivity curve of each component are calculated and analyzed by the means, which are analyzed the fatigue life of control valve and combined with reliability theory of control valve model. The impact proportion of each component on the control valve system fatigue failure was obtained. The results is shown that temperature correction factor makes the theoretical calculations of reliability more accurate, prediction life expectancy of main pressure parts accords with the technical requirements, and valve body and the sleeve have obvious influence on control system reliability, the stress concentration in key part of control valve can be reduced in the design process by improving structure.

  19. Picosecond ballistic imaging of diesel injection in high-temperature and high-pressure air

    Science.gov (United States)

    Duran, Sean P.; Porter, Jason M.; Parker, Terence E.

    2015-04-01

    The first successful demonstration of picosecond ballistic imaging using a 15-ps-pulse-duration laser in diesel sprays at temperature and pressure is reported. This technique uses an optical Kerr effect shutter constructed from a CS2 liquid cell and a 15-ps pulse at 532 nm. The optical shutter can be adjusted to produce effective imaging pulses between 7 and 16 ps. This technique is used to image the near-orifice region (first 3 mm) of diesel sprays from a high-pressure single-hole fuel injector. Ballistic imaging of dodecane and methyl oleate sprays injected into ambient air and diesel injection at preignition engine-like conditions are reported. Dodecane was injected into air heated to 600 °C and pressurized to 20 atm. The resulting images of the near-orifice region at these conditions reveal dramatic shedding of the liquid near the nozzle, an effect that has been predicted, but to our knowledge never before imaged. These shedding structures have an approximate spatial frequency of 10 mm-1 with lengths from 50 to 200 μm. Several parameters are explored including injection pressure, liquid fuel temperature, air temperature and pressure, and fuel type. Resulting trends are summarized with accompanying images.

  20. 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)

  1. Raman spectroscopic study of calcite III to aragonite transformation under high pressure and high temperature

    Science.gov (United States)

    Liu, Chuanjiang; Zheng, Haifei; Wang, Duojun

    2017-10-01

    In our study, a series of Raman experiments on the phase transition of calcite at high pressure and high temperature were investigated using a hydrothermal diamond anvil cell and Raman spectroscopy technique. It was found that calcite I transformed to calcite II and calcite III at pressures of 1.62 and 2.12 GPa and room temperature. With increasing temperature, the phase transition of calcite III to aragonite occurred. Aragonite was retained upon slowly cooling of the system, indicating that the transition of calcite III to aragonite was irreversible. Based on the available data, the phase boundary between calcite III and aragonite was determined by the following relation: P(GPa) = 0.013 × T(°C) + 1.22 (100°C ≤ T ≤ 170°C). It showed that the transition pressure linearly rose with increasing temperature. A better understanding of the stability of calcite III and aragonite is of great importance to further explore the thermodynamic behavior of carbonates and carbon cycling in the mantle.

  2. 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.

  3. Hydraulic High Pressure Valve Controller Using the In-Situ Pressure Difference

    Science.gov (United States)

    Bao, Xiaoqi (Inventor); Sherrit, Stewart (Inventor); Badescu, Mircea (Inventor); Bar-Cohen, Yoseph (Inventor); Hall, Jeffery L. (Inventor)

    2016-01-01

    A hydraulic valve controller that uses an existing pressure differential as some or all of the power source for valve operation. In a high pressure environment, such as downhole in an oil or gas well, the pressure differential between the inside of a pipe and the outside of the pipe may be adequately large to drive a linear slide valve. The valve is operated hydraulically by a piston in a bore. When a higher pressure is applied to one end of the bore and a lower pressure to the other end, the piston moves in response to the pressure differential and drives a valve attached to it. If the pressure differential is too small to drive the piston at a sufficiently high speed, a pump is provided to generate a larger pressure differential to be applied. The apparatus is conveniently constructed using multiport valves, which can be rotary valves.

  4. An experimental platform for triaxial high-pressure/high-temperature testing of rocks using computed tomography

    Science.gov (United States)

    Glatz, Guenther; Lapene, Alexandre; Castanier, Louis M.; Kovscek, Anthony R.

    2018-04-01

    A conventional high-pressure/high-temperature experimental apparatus for combined geomechanical and flow-through testing of rocks is not X-ray compatible. Additionally, current X-ray transparent systems for computed tomography (CT) of cm-sized samples are limited to design temperatures below 180 °C. We describe a novel, high-temperature (>400 °C), high-pressure (>2000 psi/>13.8 MPa confining, >10 000 psi/>68.9 MPa vertical load) triaxial core holder suitable for X-ray CT scanning. The new triaxial system permits time-lapse imaging to capture the role of effective stress on fluid distribution and porous medium mechanics. System capabilities are demonstrated using ultimate compressive strength (UCS) tests of Castlegate sandstone. In this case, flooding the porous medium with a radio-opaque gas such as krypton before and after the UCS test improves the discrimination of rock features such as fractures. The results of high-temperature tests are also presented. A Uintah Basin sample of immature oil shale is heated from room temperature to 459 °C under uniaxial compression. The sample contains kerogen that pyrolyzes as temperature rises, releasing hydrocarbons. Imaging reveals the formation of stress bands as well as the evolution and connectivity of the fracture network within the sample as a function of time.

  5. 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)

  6. 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.

  7. Inactivation of Bacillus subtilis spores by high pressure CO2 with high temperature.

    Science.gov (United States)

    Rao, Lei; Xu, Zhenzhen; Wang, Yongtao; Zhao, Feng; Hu, Xiaosong; Liao, Xiaojun

    2015-07-16

    The objective of this study was to investigate the inactivation of the Bacillus subtilis spores by high pressure CO2 combined with high temperature (HPCD+HT) and to analyze the clumping effect of the spores on their HPCD+HT resistance. The spores of B. subtilis were subjected to heat at 0.1 MPa and HPCD at 6.5-25 MPa, and 82 °C, 86 °C, and 91 °C for 0-120 min. The spores were effectively inactivated by HPCD+HT, but a protective effect on the spores was also found, which was closely correlated to the pressure, temperature and time. The spores treated by HPCD+HT at 6.5 and 10 MPa exhibited a two-stage inactivation curve of shoulder and log-linear regions whereas the spores at 15-25 MPa exhibited a three-stage inactivation curve of shoulder, log-linear and tailing regions, and these curves were well fitted to the Geeraerd model. Approximately 90% of pyridine-2,6-dicarboxylic acid (DPA) was released after HPCD+HT and the 90% DPA release time depend on the pressure and temperature. Moreover, the spore clumping in suspensions was examined by dynamic light scattering. The particle size of the spore suspensions increased with the increase of pressure, temperature and time, indicating the spore clumping. 0.1% Tween 80 as a surfactant inhibited the spore clumping and increased the inactivation ratio of the spores by HPCD+HT. These results indicated that the spore clumping enhanced the spores' resistance to HPCD+HT and induced a protective effect. Copyright © 2015 Elsevier B.V. All rights reserved.

  8. High pressure apparatus for hydrogen isotopes to pressures of 345 MPa (50,000 psi) and temperatures of 12000C

    International Nuclear Information System (INIS)

    Lakner, J.F.

    1977-01-01

    A functional new high pressure, high temperature apparatus for hydrogen isotopes uses an internally heated pressure vessel within a larger pressure vessel. The pressure capability is 345 MPa (50 K psi) at 1200 0 C. The gas pressure inside the internal vessel is balanced with gas pressure in the external vessel. The internal vessel is attached to a closure and is also the sample container. Our design allows thin-walled internal vessel construction and keeps the sample from ''seeing'' the furnace or other extraneous environment. The sample container together with the closure can easily be removed and loaded under argon using standard glove-box procedures. The small volume of the inner vessel permits small volumes of gas to be used, thus increasing the sensitivity during pressure-volume-temperature (PVT) work

  9. Performance test of ex-core high temperature and high pressure water loop test equipment (Contract research)

    International Nuclear Information System (INIS)

    Nakano, Hiroko; Uehara, Toshiaki; Takeuchi, Tomoaki; Shibata, Hiroshi; Nakamura, Jinichi; Matsui, Yoshinori; Tsuchiya, Kunihiko

    2016-03-01

    In Japan Atomic Energy Agency, we started research and development so as to monitor the situations in the Nuclear Plant Facilities during a severe accident, such as a radiation-resistant monitoring camera, a radiation-resistant transmission system for conveying the in-core information, and a heat-resistant signal cable. As a part of developments of the heat-resistant signal cable, we prepared ex-core high-temperature and high-pressure water loop test equipment, which can simulate the conditions of BWRs and PWRs, for evaluating reliability and properties of sheath materials of the cable. This equipment consists of autoclave, water conditioning tank, high-pressure metering pump, preheater, heat exchanger and water purification equipment, etc. This report describes the basic design and the performance test results of ex-core high-temperature and high-pressure water loop test equipment. (author)

  10. Experimental issues in in-situ synchrotron x-ray diffraction at high pressure and temperature by using a laser-heated diamond-anvil cell

    International Nuclear Information System (INIS)

    Yoo, C.S.

    1997-01-01

    An integrated technique of diamond-anvil cell, laser-heating and synchrotron x-ray diffraction technologies is capable of structural investigation of condensed matter in an extended region of high pressures and temperatures above 100 GPa and 3000 K. The feasibility of this technique to obtain reliable data, however, strongly depends on several experimental issues, including optical and x-ray setups, thermal gradients, pressure homogeneity, preferred orientation, and chemical reaction. In this paper, we discuss about these experimental issues together with future perspectives of this technique for obtaining accurate data

  11. High temperature and pressure electrochemical test station

    DEFF Research Database (Denmark)

    Chatzichristodoulou, Christodoulos; Allebrod, Frank; Mogensen, Mogens Bjerg

    2013-01-01

    An electrochemical test station capable of operating at pressures up to 100 bars and temperatures up to 400 ◦C has been established. It enables control of the partial pressures and mass flow of O2, N2, H2, CO2, and H2O in a single or dual environment arrangement, measurements with highly corrosive...... media, as well as localized sampling of gas evolved at the electrodes for gas analysis. A number of safety and engineering design challenges have been addressed. Furthermore, we present a series of electrochemical cell holders that have been constructed in order to accommodate different types of cells...... and facilitate different types of electrochemical measurements. Selected examples of materials and electrochemical cells examined in the test station are provided, ranging from the evaluation of the ionic conductivity of liquid electrolytic solutions immobilized in mesoporous ceramic structures...

  12. Study of elastic and thermodynamic properties of uranium dioxide under high temperature and pressure with density functional theory

    International Nuclear Information System (INIS)

    Zhou Mu; Wang Feng; Zheng Zhou; Liu Xiankun; Jiang Tao

    2013-01-01

    The elastic and thermodynamic properties of UO 2 under extreme physical condition are studied by using the density functional theory and quasi-harmonic Debye model. Results show that UO 2 is still stable ionic crystal under high temperatures, and pressures. Tetragonal shear constant is steady under high pressures and temperatures, while elastic constant C 44 is stable under high temperatures, but rises with pressure sharply. Bulk modulus, shear modulus and Young's modulus increase with pressure rapidly, but temperature would not cause evident debasement of the moduli, all of which indicate that UO 2 has excellent mechanical properties. Heat capacity of different pressures increases with temperature and is close to the Dulong-Petit limit near 1000 K. Debye temperature decreases with temperature, and increases with pressure. Under low pressure, thermal expansion coefficient raises with temperature rapidly, and then gets slow at higher pressure and temperature. Besides, the thermal expansion coefficient of UO 2 is much lower than that of other nuclear materials. (authors)

  13. Photocatalytic Degradation of Chlorobenzene by TiO2 in High-Temperature and High-Pressure Water

    Directory of Open Access Journals (Sweden)

    N. Kometani

    2008-01-01

    Full Text Available A fluidized-bed-type flow reactor available for the photocatalytic treatment of the suspension of model soil under high-temperature, high-pressure conditions was designed. An aqueous suspension containing hydrogen peroxide (H2O2 as an oxidizer and inorganic oxides as a model soil, titania (TiO2, silica (SiO2, or kaoline (Al2Si2O5(OH4 was continuously fed into the reactor with the temperature and the pressure controlled to be T=20–400∘C and P = 30 MPa, respectively. The degradation of chlorobenzene (CB in water was chosen as a model oxidation reaction. It appeared that most of the model soils are not so harmful to the SCWO treatment of CB in solutions. When the TiO2 suspension containing H2O2 was irradiated with near-UV light, the promotion of the degradation caused by photocatalytic actions of TiO2 was observed at all temperatures. Persistence of the photocatalytic activity in the oxidation reaction in high-temperature, high-pressure water would open up a possibility of the development of the hybrid process based on the combination of SCWO process and TiO2 photocatalysis for the treatment of environmental pollutants in soil and water, which are difficult to handle by conventional SCWO process or catalytic SCWO process alone.

  14. The influence of methanol on the chemical state of PtRu anodes in a high-temperature direct methanol fuel cell studied in situ by synchrotron-based near-ambient pressure x-ray photoelectron spectroscopy

    International Nuclear Information System (INIS)

    Saveleva, Viktoriia A; Savinova, Elena R; Daletou, Maria K

    2017-01-01

    Synchrotron radiation-based near-ambient pressure x-ray photoelectron spectroscopy (NAP-XPS) has recently become a powerful tool for the investigation of interfacial phenomena in electrochemical power sources such as batteries and fuel cells. Here we present an in situ NAP-XPS study of the anode of a high-temperature direct methanol fuel cell with a phosphoric acid-doped hydrocarbon membrane, which reveals an enhanced flooding of the Pt 3 Ru anode with phosphoric acid in the presence of methanol. An analysis of the electrode surface composition depending on the cell voltage and on the presence of methanol reveals the strong influence of the latter on the extent of Pt oxidation and on the transformation of Ru into Ru (IV) hydroxide. (paper)

  15. The influence of methanol on the chemical state of PtRu anodes in a high-temperature direct methanol fuel cell studied in situ by synchrotron-based near-ambient pressure x-ray photoelectron spectroscopy

    Science.gov (United States)

    Saveleva, Viktoriia A.; Daletou, Maria K.; Savinova, Elena R.

    2017-01-01

    Synchrotron radiation-based near-ambient pressure x-ray photoelectron spectroscopy (NAP-XPS) has recently become a powerful tool for the investigation of interfacial phenomena in electrochemical power sources such as batteries and fuel cells. Here we present an in situ NAP-XPS study of the anode of a high-temperature direct methanol fuel cell with a phosphoric acid-doped hydrocarbon membrane, which reveals an enhanced flooding of the Pt3Ru anode with phosphoric acid in the presence of methanol. An analysis of the electrode surface composition depending on the cell voltage and on the presence of methanol reveals the strong influence of the latter on the extent of Pt oxidation and on the transformation of Ru into Ru (IV) hydroxide.

  16. High pressure study of high temperatures superconductors: Material base, universal Tc-behavior, and charge transfer

    International Nuclear Information System (INIS)

    Chu, C.W.; Hor, P.H.; Lin, J.G.; Xiong, Q.; Huang, Z.J.; Meng, R.L.; Xue, Y.Y.; Jean, Y.C.

    1991-01-01

    The superconducting transition temperature (T c ) has been measured in YBa 2 Cu 3 O 6.7 , YBa 2 Cu 3 O 7 , Y 2 Ba 4 Cu 7 O 15 , YBa 2 Cu 4 O 8 , Tl 2 Ba 2 Ca n-1 Cu n O n+4-δ , La 2-x Sr x CuO 4 , and La 2-x Ba x CuO 4 under high pressures. The pressure effect on the positron lifetime (τ) has also been determined in the first four compounds. Based on these and other high pressure data, the authors suggest that (1) all known cuprate high temperature superconductors (HTS's) may be no more than mere modifications of either 214-T, 214-T', 123, or a combination of 214-T' and 123, (2) a nonmonotonic T c -behavior may govern the T c -variation of all hole cuprate HTS's and (3) pressure can induce charge transfer leading to a T c -change. The implications of these suggestions will also be discussed

  17. X-ray imaging for studying behavior of liquids at high pressures and high temperatures using Paris-Edinburgh press

    International Nuclear Information System (INIS)

    Kono, Yoshio; Kenney-Benson, Curtis; Park, Changyong; Shen, Guoyin; Shibazaki, Yuki; Wang, Yanbin

    2015-01-01

    Several X-ray techniques for studying structure, elastic properties, viscosity, and immiscibility of liquids at high pressures have been integrated using a Paris-Edinburgh press at the 16-BM-B beamline of the Advanced Photon Source. Here, we report the development of X-ray imaging techniques suitable for studying behavior of liquids at high pressures and high temperatures. White X-ray radiography allows for imaging phase separation and immiscibility of melts at high pressures, identified not only by density contrast but also by phase contrast imaging in particular for low density contrast liquids such as silicate and carbonate melts. In addition, ultrafast X-ray imaging, at frame rates up to ∼10 5 frames/second (fps) in air and up to ∼10 4 fps in Paris-Edinburgh press, enables us to investigate dynamics of liquids at high pressures. Very low viscosities of melts similar to that of water can be reliably measured. These high-pressure X-ray imaging techniques provide useful tools for understanding behavior of liquids or melts at high pressures and high temperatures

  18. X-ray imaging for studying behavior of liquids at high pressures and high temperatures using Paris-Edinburgh press

    Energy Technology Data Exchange (ETDEWEB)

    Kono, Yoshio; Kenney-Benson, Curtis; Park, Changyong; Shen, Guoyin [HPCAT, Geophysical Laboratory, Carnegie Institution of Washington, 9700 S. Cass Ave., Argonne, Illinois 60439 (United States); Shibazaki, Yuki [Frontier Research Institute for Interdisciplinary Sciences, Tohoku University, Aramaki aza Aoba 6-3, Aoba-ku, Sendai 980-8578 (Japan); Wang, Yanbin [GeoSoilEnviroCARS, Center for Advanced Radiation Sources, The University of Chicago, 5640 S. Ellis Avenue, Chicago, Illinois 60637 (United States)

    2015-07-15

    Several X-ray techniques for studying structure, elastic properties, viscosity, and immiscibility of liquids at high pressures have been integrated using a Paris-Edinburgh press at the 16-BM-B beamline of the Advanced Photon Source. Here, we report the development of X-ray imaging techniques suitable for studying behavior of liquids at high pressures and high temperatures. White X-ray radiography allows for imaging phase separation and immiscibility of melts at high pressures, identified not only by density contrast but also by phase contrast imaging in particular for low density contrast liquids such as silicate and carbonate melts. In addition, ultrafast X-ray imaging, at frame rates up to ∼10{sup 5} frames/second (fps) in air and up to ∼10{sup 4} fps in Paris-Edinburgh press, enables us to investigate dynamics of liquids at high pressures. Very low viscosities of melts similar to that of water can be reliably measured. These high-pressure X-ray imaging techniques provide useful tools for understanding behavior of liquids or melts at high pressures and high temperatures.

  19. Real-time measurements of temperature, pressure and moisture profiles in High-Performance Concrete exposed to high temperatures during neutron radiography imaging

    Energy Technology Data Exchange (ETDEWEB)

    Toropovs, N., E-mail: nikolajs.toropovs@rtu.lv [Empa, Swiss Federal Laboratories for Materials Science and Technology, Dübendorf (Switzerland); Riga Technical University, Institute of Materials and Structures, Riga (Latvia); Lo Monte, F. [Politecnico di Milano, Department of Civil and Environmental Engineering, Milan (Italy); Wyrzykowski, M. [Empa, Swiss Federal Laboratories for Materials Science and Technology, Dübendorf (Switzerland); Lodz University of Technology, Department of Building Physics and Building Materials, Lodz (Poland); Weber, B. [Empa, Swiss Federal Laboratories for Materials Science and Technology, Dübendorf (Switzerland); Sahmenko, G. [Riga Technical University, Institute of Materials and Structures, Riga (Latvia); Vontobel, P. [Paul Scherrer Institute, Laboratory for Neutron Scattering and Imaging, Villigen (Switzerland); Felicetti, R. [Politecnico di Milano, Department of Civil and Environmental Engineering, Milan (Italy); Lura, P. [Empa, Swiss Federal Laboratories for Materials Science and Technology, Dübendorf (Switzerland); ETH Zürich, Institute for Building Materials (IfB), Zürich (Switzerland)

    2015-02-15

    High-Performance Concrete (HPC) is particularly prone to explosive spalling when exposed to high temperature. Although the exact causes that lead to spalling are still being debated, moisture transport during heating plays an important role in all proposed mechanisms. In this study, slabs made of high-performance, low water-to-binder ratio mortars with addition of superabsorbent polymers (SAP) and polypropylene fibers (PP) were heated from one side on a temperature-controlled plate up to 550 °C. A combination of measurements was performed simultaneously on the same sample: moisture profiles via neutron radiography, temperature profiles with embedded thermocouples and pore pressure evolution with embedded pressure sensors. Spalling occurred in the sample with SAP, where sharp profiles of moisture and temperature were observed. No spalling occurred when PP-fibers were introduced in addition to SAP. The experimental procedure described here is essential for developing and verifying numerical models and studying measures against fire spalling risk in HPC.

  20. Exploring nuclear magnetic resonance at the highest pressure. Closing the pseudogap under pressure in a high temperature superconductor

    Energy Technology Data Exchange (ETDEWEB)

    Meissner, Thomas

    2013-05-13

    In the present work, a novel probe design for high pressure NMR experiments in gem anvil cells (GAC) was used which places a small microcoil inside the high pressure volume as the detection coil. Based on tests carried out at ambient pressure and high pressure of 42 kbar it is demonstrated that this approach is indeed feasible and results in an increase of sensitivity by two orders of magnitude compared to previous GAC-NMR designs. The design was then successfully employed in the investigation of the electronic properties of metallic aluminum and the high temperature superconductor YBa{sub 2}Cu{sub 4}O{sub 8} at pressures of up to 101 kbar. Because of its improved sensitivity and the potential to achieve even higher pressures, the microcoil GAC-NMR setup should prove useful in the investigation of materials under high pressure conditions in the future. In the case of metallic aluminum, the effect of pressure on the electronic density of states at the Fermi level was probed via the Knight-shift K and the spin-lattice relaxation time T{sub 1} at room temperature up to a pressure of 101 kbar, extending the pressure range of previous NMR measurements by a factor of 14 [72]. Most notably, a decrease of K(p) by 11% is detected in the investigated pressure range that is inconsistent with a free electron behavior of the density of states. Numerical band structure calculations that are in excellent agreement with the experimental data suggest that the observed changes of K and T{sub 1} are due to a kink in the electronic states at a Lifshitz-transition at about 75 kbar which has not been observed previously. A further decrease of K by a factor of 2 is predicted to occur in the pressure range up to 300 kbar. In addition, an increase of the NMR linewidths of the metallic aluminum signal was observed above about 42 kbar that is inconsistent with a pure dipolar linewidth. Based on an analysis of the field dependence of this effect it was ascribed to a small additional

  1. Exploring nuclear magnetic resonance at the highest pressure. Closing the pseudogap under pressure in a high temperature superconductor

    International Nuclear Information System (INIS)

    Meissner, Thomas

    2013-01-01

    In the present work, a novel probe design for high pressure NMR experiments in gem anvil cells (GAC) was used which places a small microcoil inside the high pressure volume as the detection coil. Based on tests carried out at ambient pressure and high pressure of 42 kbar it is demonstrated that this approach is indeed feasible and results in an increase of sensitivity by two orders of magnitude compared to previous GAC-NMR designs. The design was then successfully employed in the investigation of the electronic properties of metallic aluminum and the high temperature superconductor YBa 2 Cu 4 O 8 at pressures of up to 101 kbar. Because of its improved sensitivity and the potential to achieve even higher pressures, the microcoil GAC-NMR setup should prove useful in the investigation of materials under high pressure conditions in the future. In the case of metallic aluminum, the effect of pressure on the electronic density of states at the Fermi level was probed via the Knight-shift K and the spin-lattice relaxation time T 1 at room temperature up to a pressure of 101 kbar, extending the pressure range of previous NMR measurements by a factor of 14 [72]. Most notably, a decrease of K(p) by 11% is detected in the investigated pressure range that is inconsistent with a free electron behavior of the density of states. Numerical band structure calculations that are in excellent agreement with the experimental data suggest that the observed changes of K and T 1 are due to a kink in the electronic states at a Lifshitz-transition at about 75 kbar which has not been observed previously. A further decrease of K by a factor of 2 is predicted to occur in the pressure range up to 300 kbar. In addition, an increase of the NMR linewidths of the metallic aluminum signal was observed above about 42 kbar that is inconsistent with a pure dipolar linewidth. Based on an analysis of the field dependence of this effect it was ascribed to a small additional quadrupolar broadening which is

  2. The influence of defects on the transport properties of AgSbPb18Te20 prepared at high pressure and high temperature

    International Nuclear Information System (INIS)

    Wang Yi; Zhu Pinwen; Jiao Hujun; Chen Haiyong; Ma Yanming; Niu Yingli; Li Yingai; Zhang Lijun; Zhang Tiechen; Gao Chunxiao; Zou Guangtian

    2007-01-01

    We synthesized polycrystal AgSbPb 18 Te 20 by using the method of high pressure and high temperature, and found that the defects produced by high pressure and high temperature caused the changes of transport properties. X-ray diffraction patterns showed that the cell parameters did not change obviously with synthesis at high pressure, apart from a small fluctuation. The electrical resistivity first increased, and then decreased to one quarter of the original value, as the synthesis pressure changed from low to high. The Seebeck coefficient decreased with the increase of synthesis pressure, and then changed from positive to negative. High pressure and high temperature could cause AgSbPb 18 Te 20 to change from a p-type to n-type semiconductor, increase the carrier concentration at maximum by two orders of magnitude, and shift the infrared absorption edge to a higher energy range. All of these phenomena were regarded as showing that high pressure and high temperature favored the formation of certain defects which could change the band structure and thereby change the transport properties

  3. Structural and electrical properties of TmTe under high pressure

    International Nuclear Information System (INIS)

    Tang, Jie; Matsumoto, Takehiko; Kosaka, Takayuki; Matsumura, Takeshi; Suzuki, Takashi; Mori, Nobuo

    1997-01-01

    Pressure-induced valence state of Tm ions in TmTe has been investigated by measurements of electrical resistivity in situ x-ray diffraction and magnetic susceptibility at high pressure. Below 2 GPa, the valence of Tm was confirmed to be 2 + from the results of compressibility and magnetic susceptibility. The pressure dependence of the electrical resistivity up to 2 GPa at room temperature showed an exponential decrease, indicating a linear closing of the energy gap at a rate of -1 meV/GPa. In the pressure range above 2 GPa where the energy gap disappeared, the valence transition from Tm 2+ to Tm 3+ was concluded from the pressure dependence of the lattice parameters. The electrical resistivity showing a logarithmic temperature dependence was reminiscent of Kondo effect. Above 6 GPa at which the pressure dependence of electrical resistivity abruptly decreased, the structure was confirmed to transform from the NaCl-type with Tm 3+ to a tetragonal structure. (author)

  4. The effect of pressurization path on high pressure gas forming of Ti-3Al-2.5V at elevated temperature

    Directory of Open Access Journals (Sweden)

    Liu Gang

    2015-01-01

    Full Text Available High pressure gas forming is a tubular component forming technology with pressurized gas at elevated temperature, based on QPF, HMGF and Hydroforming. This process can be used to form tube blank at lower temperatures with high energy efficiency and also at higher strain rates. With Ti-3Al-2.5V Ti-alloy tube, the potential of HPGF was studied further through experiments at the elevated temperatures of 650 ∘C and 700 ∘C. In order to know the formability of the Ti-alloy tube, tensile tests were also carried out. The results show that: at the temperatures of 650 ∘C and 700 ∘C, the flow curves exhibit the power-law constitutive relation until peak stress is reached and the deformability is suitable for the HPGF process of Ti-3Al-2.5V alloy tube. The effects of pressurization path on the corner filling process and thickness profile are obvious. The high pressure inflow process can result in temperature difference between the straight wall area and corner area, which makes the thickness profile special. Besides, with the stepped pressurization path, the more constant filling rate and better thickness profile can be obtained.

  5. 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.

  6. 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)

  7. A novel high pressure, high temperature vessel used to conduct long-term stability measurements of silicon MEMS pressure transducers

    Science.gov (United States)

    Wisniewiski, David

    2014-03-01

    The need to quantify and to improve long-term stability of pressure transducers is a persistent requirement from the aerospace sector. Specifically, the incorporation of real-time pressure monitoring in aircraft landing gear, as exemplified in Tire Pressure Monitoring Systems (TPMS), has placed greater demand on the pressure transducer for improved performance and increased reliability which is manifested in low lifecycle cost and minimal maintenance downtime through fuel savings and increased life of the tire. Piezoresistive (PR) silicon MEMS pressure transducers are the primary choice as a transduction method for this measurement owing to their ability to be designed for the harsh environment seen in aircraft landing gear. However, these pressure transducers are only as valuable as the long-term stability they possess to ensure reliable, real-time monitoring over tens of years. The "heart" of the pressure transducer is the silicon MEMS element, and it is at this basic level where the long-term stability is established and needs to be quantified. A novel High Pressure, High Temperature (HPHT) vessel has been designed and constructed to facilitate this critical measurement of the silicon MEMS element directly through a process of mechanically "floating" the silicon MEMS element while being subjected to the extreme environments of pressure and temperature, simultaneously. Furthermore, the HPHT vessel is scalable to permit up to fifty specimens to be tested at one time to provide a statistically significant data population on which to draw reasonable conclusions on long-term stability. With the knowledge gained on the silicon MEMS element, higher level assembly to the pressure transducer envelope package can also be quantified as to the build-effects contribution to long-term stability in the same HPHT vessel due to its accommodating size. Accordingly, a HPHT vessel offering multiple levels of configurability and robustness in data measurement is presented, along

  8. 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

  9. Coherent Raman scattering in high-pressure/high-temperature fluids: An overview

    International Nuclear Information System (INIS)

    Schmidt, S.C.; Moore, D.S.

    1990-01-01

    The present understanding of high-pressure/high-temperature dense-fluid behavior is derived almost exclusively from hydrodynamic and thermodynamic measurements. Such results average over the microscopic aspects of the materials and are, therefore, insufficient for a complete understanding of fluid behavior. At the present, dense-fluid models can be verified only to the extend that they agree with the macroscopic measurements. Recently, using stimulated Raman scattering, Raman induced Kerr effect scattering, and coherent anti-Stokes Raman scattering, we have been able to probe some of the microscopic phenomenology of these dense fluids. In this paper, we discuss primarily the use of CARS in conjunction with a two-stage light-gas gun to obtain vibrational spectra of shock-compressed liquid N 2 , O 2 , CO, their mixtures, CH 3 NO 2 , and N 2 O. These experimental spectra are compared to synthetic spectra calculated using a semiclassical model for CARS intensities and best fit vibrational frequencies, peak Raman susceptibilities, and Raman linewidths. For O 2 , the possibility of resonance enhancement from collision-induced absorption is addressed. Shifts in the vibrational frequencies reflect the influence of increased density and temperature on the intramolecular motion. The derived parameters suggest thermal equilibrium of the vibrational levels is established less than a few nanoseconds after shock passage. Vibrational temperatures are obtained that agree with those derived from equation-of-state calculations. Measured linewidths suggest that vibrational dephasing times have decreased to subpicosecond values at the highest shock pressures

  10. Investigation on the Permeability Evolution of Gypsum Interlayer Under High Temperature and Triaxial Pressure

    Science.gov (United States)

    Tao, Meng; Yechao, You; Jie, Chen; Yaoqing, Hu

    2017-08-01

    The permeability of the surrounding rock is a critical parameter for the designing and assessment of radioactive waste disposal repositories in the rock salt. Generally, in the locations that are chosen for radioactive waste storage, the bedded rock salt is a sedimentary rock that contains NaCl and Na2SO4. Most likely, there are also layers of gypsum ( {CaSO}_{ 4} \\cdot 2 {H}_{ 2} {O)} present in the salt deposit. Radioactive wastes emit a large amount of heat and hydrogen during the process of disposal, which may result in thermal damage of the surrounding rocks and cause a great change in their permeability and tightness. Therefore, it is necessary to investigate the permeability evolution of the gypsum interlayer under high temperature and high pressure in order to evaluate the tightness and security of the nuclear waste repositories in bedded rock salt. In this study, a self-designed rock triaxial testing system by which high temperature and pressure can be applied is used; the μCT225kVFCB micro-CT system is also employed to investigate the permeability and microstructure of gypsum specimens under a constant hydrostatic pressure of 25 MPa, an increasing temperature (ranging from 20 to 650 °C), and a variable inlet gas pressure (1, 2, 4, 6 MPa). The experimental results show: (a) the maximum permeability measured during the whole experiment is less than 10-17 m2, which indicates that the gypsum interlayer has low permeability under high temperature and pressure that meet the requirements for radioactive waste repository. (b) Under the same temperature, the permeability of the gypsum specimen decreases at the beginning and then increases as the pore pressure elevates. When the inlet gas pressure is between 0 and 2 MPa, the Klinkenberg effect is very pronounced. Then, as the pore pressure increases, the movement behavior of gas molecules gradually changes from free motion to forced directional motion. So the role of free movement of gas molecules gradually

  11. High-pressure high-temperature stability of hcp-IrxOs1-x (x = 0.50 and 0.55) alloys

    Energy Technology Data Exchange (ETDEWEB)

    Yusenko, Kirill V.; Bykova, Elena; Bykov, Maxim; Gromilov, Sergey A.; Kurnosov, Alexander V.; Prescher, Clemens; Prakapenka, Vitali B.; Crichton, Wilson A.; Hanfland, Michael; Margadonna, Serena; Dubrovinsky, Leonid S.

    2016-12-23

    Hcp-Ir0.55Os0.45 and hcp-Ir0.50Os0.50 alloys were synthesised by thermal decomposition of single-source precursors in hydrogen atmosphere. Both alloys correspond to a miscibility gap in the Ir–Os binary phase diagram and therefore are metastable at ambient conditions. An in situ powder X-ray diffraction has been used for a monitoring a formation of hcp-Ir0.55Os0.45 alloy from (NH4)2[Ir0.55Os0.45Cl6] precursor. A crystalline intermediate compound and nanodimentional metallic particles with a large concentration of defects has been found as key intermediates in the thermal decomposition process in hydrogen flow. High-temperature stability of titled hcp-structured alloys has been investigated upon compression up to 11 GPa using a multi-anvil press and up to 80 GPa using laser-heated diamond-anvil cells to obtain a phase separation into fcc + hcp mixture. Compressibility curves at room temperature as well as thermal expansion at ambient pressure and under compression up to 80 GPa were collected to obtain thermal expansion coefficients and bulk moduli. hcp-Ir0.55Os0.45 alloy shows bulk moduli B0 = 395 GPa. Thermal expansion coefficients were estimated as α = 1.6·10-5 K-1 at ambient pressure and α = 0.3·10-5 K-1 at 80 GPa. Obtained high-pressure high-temperature data allowed us to construct the first model for pressure-dependent Ir–Os phase diagram.

  12. A high-temperature high-pressure calorimeter for determining heats of solution up to 623 K.

    Science.gov (United States)

    Djamali, Essmaiil; Turner, Peter J; Murray, Richard C; Cobble, James W

    2010-07-01

    A high-temperature high-pressure isoperibol calorimeter for determining the heats of solution and reaction of very dilute substances in water (10(-4) m) at temperatures up to 623 K is described. The energies of vaporization of water at steam saturation pressure were measured as a function of temperature and the results agree with the corresponding values from steam tables to better than 0.08+/-0.18%. The novelties of the present instrument relative to flow type heat capacity calorimeters are that measurements can be made at orders of magnitude lower concentrations and that measurement of heat of reaction involving solids or gases or in the presence of high concentrations of supporting electrolytes, acids, and bases is possible. Furthermore, the advantage of using enthalpy data over heat capacity data for calculations of the standard state Gibbs free energies of electrolytes is that the experimental heat data of this research need only be integrated once to derive higher temperature free energy data from lower temperatures. The derived heat capacities can be used mathematically to obtain free energies by double integration. However, the resulting errors are much smaller than if experimental aqueous heat capacities were used for the integrations.

  13. High temperature piezoresistive {beta}-SiC-on-SOI pressure sensor for combustion engines

    Energy Technology Data Exchange (ETDEWEB)

    Berg, J. von; Ziermann, R.; Reichert, W.; Obermeier, E. [Tech. Univ. Berlin (Germany). Microsensor and Actuator Technol. Center; Eickhoff, M.; Kroetz, G. [Daimler Benz AG, Munich (Germany); Thoma, U.; Boltshauser, T.; Cavalloni, C. [Kistler Instrumente AG, Winterthur (Switzerland); Nendza, J.P. [TRW Deutschland GmbH, Barsinghausen (Germany)

    1998-08-01

    For measuring the cylinder pressure in combustion engines of automobiles a high temperature pressure sensor has been developed. The sensor is made of a membrane based piezoresistive {beta}-SiC-on-SOI (SiCOI) sensor chip and a specially designed housing. The SiCOI sensor was characterized under static pressures of up to 200 bar in the temperature range between room temperature and 300 C. The sensitivity of the sensor at room temperature is approximately 0.19 mV/bar and decreases to about 0.12 mV/bar at 300 C. For monitoring the dynamic cylinder pressure the sensor was placed into the combustion chamber of a gasoline engine. The measurements were performed at 1500 rpm under different loads, and for comparison a quartz pressure transducer from Kistler AG was used as a reference. The maximum pressure at partial load operation amounts to about 15 bar. The difference between the calibrated SiCOI sensor and the reference sensor is significantly less than 1 bar during the whole operation. (orig.) 8 refs.

  14. 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...

  15. Novel High Temperature Capacitive Pressure Sensor Utilizing SiC Integrated Circuit Twin Ring Oscillators

    Science.gov (United States)

    Scardelletti, M.; Neudeck, P.; Spry, D.; Meredith, R.; Jordan, J.; Prokop, N.; Krasowski, M.; Beheim, G.; Hunter, G.

    2017-01-01

    This paper describes initial development and testing of a novel high temperature capacitive pressure sensor system. The pressure sensor system consists of two 4H-SiC 11-stage ring oscillators and a SiCN capacitive pressure sensor. One oscillator has the capacitive pressure sensor fixed at one node in its feedback loop and varies as a function of pressure and temperature while the other provides a pressure-independent reference frequency which can be used to temperature compensate the output of the first oscillator. A two-day repeatability test was performed up to 500C on the oscillators and the oscillator fundamental frequency changed by only 1. The SiCN capacitive pressure sensor was characterized at room temperature from 0 to 300 psi. The sensor had an initial capacitance of 3.76 pF at 0 psi and 1.75 pF at 300 psi corresponding to a 54 change in capacitance. The integrated pressure sensor system was characterized from 0 to 300 psi in steps of 50 psi over a temperature range of 25 to 500C. The pressure sensor system sensitivity was 0.113 kHzpsi at 25C and 0.026 kHzpsi at 500C.

  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. Frictional characteristics of silicon graphite lubricated with water at high pressure and high temperature

    International Nuclear Information System (INIS)

    Lee, Jae Seon; Kim, Eun Hyun; Park, Jin Seok; Kim, Jong In

    2001-01-01

    Experimental frictional and wear characteristics of silicon graphite materials is studied in this paper. Those specimens are lubricated with high temperature and highly pressurized water to simulate the same operating condition for the journal bearing and the thrust bearing on the main coolant pump bearing in the newly developing nuclear reactor named SMART(System-integrated Modular Advanced ReacTor). Operating condition of the bearings is realized by the tribometer and the autoclave. Friction coefficient and wear loss are analyzed to choose the best silicon graphite material. Pin on plate test specimens are used and coned disk springs are used to control the applied force on the specimens. Wear loss and wear width are measured by a precision balance and a micrometer. The friction force is measured by the strain gauge which can be used under high temperature and high pressure. Three kinds of silicon graphite materials are examined and compared with each other, and each material shows similar but different results on frictional and wear characteristics

  18. 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.

  19. High-pressure high-temperature experiments: Windows to the Universe; Experimentos a alta presion y alta temperatura: Ventanas al universo

    Energy Technology Data Exchange (ETDEWEB)

    Santaria-Perez, D.

    2011-07-01

    From Earth compositional arguments suggested by indirect methods, such as the propagation of seismic waves, is possible to generate in the laboratory pressure and temperature conditions similar to those of the Earth or other planet interiors and to study how these conditions affect to a certain metal or mineral. These experiments are, therefore, windows to the Universe. The aim of this chapter is to illustrate the huge power of the experimental high-pressure high-temperature techniques and give a global overview of their application to different geophysical fields. Finally, we will introduce the MALTA Consolider Team, which gather most of the Spanish high-pressure community, and present their available high-pressure facilities. (Author) 28 refs.

  20. Comparison of Diesel Spray Combustion in Different High-temperature, High-pressure Facilities

    DEFF Research Database (Denmark)

    Pickett, Lyle M.; Genzale, Caroline L.; Bruneaux, Gilles

    2010-01-01

    Diesel spray experimentation at controlled high-temperature and high-pressure conditions is intended to provide a more fundamental understanding of diesel combustion than can be achieved in engine experiments. This level of understanding is needed to develop the high-fidelity multi-scale CFD models...... participants in the ECN. Thus, in addition to the presentation of a comparative study, this paper demonstrates steps that are needed for other interested groups to participate in ECN spray research. We expect that this collaborative effort will generate a high-quality dataset to be used for advanced...

  1. High pressure-temperature processing as an alternative for preserving basil

    NARCIS (Netherlands)

    Krebbers, B.; Matser, A.; Koets, M.; Bartels, P.; Berg, van den R.

    2002-01-01

    In this study the effect of sterilisation by high pressure (HP) on the quality of basil was compared to conventional processing techniques. By means of freezing, or blanching followed by drying, microbial reduction of spores was maximal one-log. Pulsed HP-temperature treatment yielded a reduction of

  2. 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.

  3. In situ oxide dispersion strengthened tungsten alloys with high compressive strength and high strain-to-failure

    International Nuclear Information System (INIS)

    Huang, Lin; Jiang, Lin; Topping, Troy D.; Dai, Chen; Wang, Xin; Carpenter, Ryan; Haines, Christopher; Schoenung, Julie M.

    2017-01-01

    In this work a novel process methodology to concurrently improve the compressive strength (2078 MPa at a strain rate of 5 × 10"−"4 s"−"1) and strain-to-failure (over 40%) of bulk tungsten materials has been described. The process involves the in situ formation of intragranular tungsten oxide nanoparticles, facilitated by the application of a pressure of 1 GPa at a low sintering temperature of 1200 °C during spark plasma sintering (SPS). The results show that the application of a high pressure of 1 GPa during SPS significantly accelerates the densification process. Concurrently, the second phase oxide nanoparticles with an average grain size of 108 nm, which are distributed within the interiors of the W grains, simultaneously provide strengthening and plasticity by inhibiting grain growth, and generating, blocking, and storing dislocations. - Graphical abstract: In this work a novel process methodology to concurrently improve the compressive strength (2078 MPa at a strain rate of 5 × 10"−"4 s"−"1) and strain-to-failure (over 40%) of bulk W materials has been described. The process involves the in situ formation of intragranular tungsten oxide nanoparticles, facilitated by the application of a pressure of 1 GPa at a low sintering temperature of 1200 °C during spark plasma sintering (SPS).

  4. High Temperature, High Pressure Equation of State: Solidification of Hydrocarbons and Measurement of Krytox Oil Using Rolling-Ball Viscometer Validation

    Energy Technology Data Exchange (ETDEWEB)

    Gamwo, Isaac K. [National Energy Technology Lab. (NETL), Pittsburgh, PA, (United States); Burgess, Ward [National Energy Technology Lab. (NETL), Pittsburgh, PA, (United States); Tapriyal, Deepak [National Energy Technology Lab. (NETL), Pittsburgh, PA, (United States)

    2014-10-03

    The global consumption of oil and gas continues to rise and has led to the search and recovery of petroleum sources from reservoirs exhibiting increasingly high-temperature, high-pressure conditions. For example, ultra-deep petroleum formations found at depths of approximately 5 km or more, can exhibit pressure and temperature values as high as 240 MPa (35,000 psi) and 533 K (260°C). The hydrocarbons produced from these ultra-deep formations experience significant decreases in temperature and pressure from reservoir to platform conditions. Hence, it is highly desirable to develop accurate equation of state models (EOS) and fluid properties databases that covers the entire temperature and pressure ranges associated with this process to promote the efficient, safe, and environmentally responsible production from these reservoirs at extreme conditions. Currently available databases and EOS models are generally limited to approximately 69 MPa and do not correlate accurately when extrapolated to the extreme environments associated with ultra-deep reservoirs where temperatures can reach as high as 533 K and pressures up to 240 MPa. Despite recent exploration and production of petroleum from ultra-deep formations, there are major gaps in the databases for pure and mixture density and viscosity of hydrocarbons. These are the most important fluid properties that enable accurate booking of reserves as well as the design of size and equipment to safely bring these fluids to the platform. The overall objective of this project is to develop methodologies to provide crude oil thermodynamic and transport properties—including density, viscosity, and phase composition— at extreme temperature and pressure conditions. The knowledge of these crude oil properties reduces uncertainties associated with deep drilling and promotes safer and reliable access to domestic energy resources. This report is an extension of work reported in our first Technical Report Series (TRS) released

  5. Pressure drop and heat transfer characteristics of a high-temperature printed circuit heat exchanger

    International Nuclear Information System (INIS)

    Chen, Minghui; Sun, Xiaodong; Christensen, Richard N.; Skavdahl, Isaac; Utgikar, Vivek; Sabharwall, Piyush

    2016-01-01

    Highlights: • Pressure drop and heat transfer characteristics of a high-temperature printed circuit heat exchanger have been obtained. • Comparisons of experimental data and available correlations have been performed. • New Fanning friction factor and heat transfer correlations for the test PCHE are developed. - Abstract: Printed circuit heat exchanger (PCHE) is one of the leading intermediate heat exchanger (IHX) candidates to be employed in the very-high-temperature gas-cooled reactors (VHTRs) due to its capability for high-temperature, high-pressure applications. In the current study, a reduced-scale zigzag-channel PCHE was fabricated using Alloy 617 plates for the heat exchanger core and Alloy 800H pipes for the headers. The pressure drop and heat transfer characteristics of the PCHE were investigated experimentally in a high-temperature helium test facility (HTHF) at The Ohio State University. The PCHE helium inlet temperatures and pressures were varied up to 464 °C/2.7 MPa for the cold side and 802 °C/2.7 MPa for the hot side, respectively, while the maximum helium mass flow rates on both sides of the PCHE reached 39 kg/h. The corresponding maximum channel Reynolds number was approximately 3558, covering the laminar flow and laminar-to-turbulent flow transition regimes. New pressure drop and heat transfer correlations for the current zigzag channels with rounded bends were developed based on the experimental data. Comparisons between the experimental data and the results obtained from the available PCHE and straight circular pipe correlations were conducted. Compared to the heat transfer performance in straight circular pipes, the zigzag channels provided little advantage in the laminar flow regime but significant advantage near the transition flow regime.

  6. Characterization of thick and thin film SiCN for pressure sensing at high temperatures.

    Science.gov (United States)

    Leo, Alfin; Andronenko, Sergey; Stiharu, Ion; Bhat, Rama B

    2010-01-01

    Pressure measurement in high temperature environments is important in many applications to provide valuable information for performance studies. Information on pressure patterns is highly desirable for improving performance, condition monitoring and accurate prediction of the remaining life of systems that operate in extremely high temperature environments, such as gas turbine engines. A number of technologies have been recently investigated, however these technologies target specific applications and they are limited by the maximum operating temperature. Thick and thin films of SiCN can withstand high temperatures. SiCN is a polymer-derived ceramic with liquid phase polymer as its starting material. This provides the advantage that it can be molded to any shape. CERASET™ also yields itself for photolithography, with the addition of photo initiator 2, 2-Dimethoxy-2-phenyl-acetophenone (DMPA), thereby enabling photolithographical patterning of the pre-ceramic polymer using UV lithography. SiCN fabrication includes thermosetting, crosslinking and pyrolysis. The technology is still under investigation for stability and improved performance. This work presents the preparation of SiCN films to be used as the body of a sensor for pressure measurements in high temperature environments. The sensor employs the phenomenon of drag effect. The pressure sensor consists of a slender sensitive element and a thick blocking element. The dimensions and thickness of the films depend on the intended application of the sensors. Fabrication methods of SiCN ceramics both as thin (about 40-60 μm) and thick (about 2-3 mm) films for high temperature applications are discussed. In addition, the influence of thermosetting and annealing processes on mechanical properties is investigated.

  7. Characterization of Thick and Thin Film SiCN for Pressure Sensing at High Temperatures

    Directory of Open Access Journals (Sweden)

    Rama B. Bhat

    2010-02-01

    Full Text Available Pressure measurement in high temperature environments is important in many applications to provide valuable information for performance studies. Information on pressure patterns is highly desirable for improving performance, condition monitoring and accurate prediction of the remaining life of systems that operate in extremely high temperature environments, such as gas turbine engines. A number of technologies have been recently investigated, however these technologies target specific applications and they are limited by the maximum operating temperature. Thick and thin films of SiCN can withstand high temperatures. SiCN is a polymer-derived ceramic with liquid phase polymer as its starting material. This provides the advantage that it can be molded to any shape. CERASET™ also yields itself for photolithography, with the addition of photo initiator 2, 2-Dimethoxy-2-phenyl-acetophenone (DMPA, thereby enabling photolithographical patterning of the pre-ceramic polymer using UV lithography. SiCN fabrication includes thermosetting, crosslinking and pyrolysis. The technology is still under investigation for stability and improved performance. This work presents the preparation of SiCN films to be used as the body of a sensor for pressure measurements in high temperature environments. The sensor employs the phenomenon of drag effect. The pressure sensor consists of a slender sensitive element and a thick blocking element. The dimensions and thickness of the films depend on the intended application of the sensors. Fabrication methods of SiCN ceramics both as thin (about 40–60 µm and thick (about 2–3 mm films for high temperature applications are discussed. In addition, the influence of thermosetting and annealing processes on mechanical properties is investigated.

  8. A Smart High Accuracy Silicon Piezoresistive Pressure Sensor Temperature Compensation System

    Directory of Open Access Journals (Sweden)

    Guanwu Zhou

    2014-07-01

    Full Text Available Theoretical analysis in this paper indicates that the accuracy of a silicon piezoresistive pressure sensor is mainly affected by thermal drift, and varies nonlinearly with the temperature. Here, a smart temperature compensation system to reduce its effect on accuracy is proposed. Firstly, an effective conditioning circuit for signal processing and data acquisition is designed. The hardware to implement the system is fabricated. Then, a program is developed on LabVIEW which incorporates an extreme learning machine (ELM as the calibration algorithm for the pressure drift. The implementation of the algorithm was ported to a micro-control unit (MCU after calibration in the computer. Practical pressure measurement experiments are carried out to verify the system’s performance. The temperature compensation is solved in the interval from −40 to 85 °C. The compensated sensor is aimed at providing pressure measurement in oil-gas pipelines. Compared with other algorithms, ELM acquires higher accuracy and is more suitable for batch compensation because of its higher generalization and faster learning speed. The accuracy, linearity, zero temperature coefficient and sensitivity temperature coefficient of the tested sensor are 2.57% FS, 2.49% FS, 8.1 × 10−5/°C and 29.5 × 10−5/°C before compensation, and are improved to 0.13%FS, 0.15%FS, 1.17 × 10−5/°C and 2.1 × 10−5/°C respectively, after compensation. The experimental results demonstrate that the proposed system is valid for the temperature compensation and high accuracy requirement of the sensor.

  9. Ultrahigh Temperature Capacitive Pressure Sensor

    Science.gov (United States)

    Harsh, Kevin

    2014-01-01

    Robust, miniaturized sensing systems are needed to improve performance, increase efficiency, and track system health status and failure modes of advanced propulsion systems. Because microsensors must operate in extremely harsh environments, there are many technical challenges involved in developing reliable systems. In addition to high temperatures and pressures, sensing systems are exposed to oxidation, corrosion, thermal shock, fatigue, fouling, and abrasive wear. In these harsh conditions, sensors must be able to withstand high flow rates, vibration, jet fuel, and exhaust. In order for existing and future aeropropulsion turbine engines to improve safety and reduce cost and emissions while controlling engine instabilities, more accurate and complete sensor information is necessary. High-temperature (300 to 1,350 C) capacitive pressure sensors are of particular interest due to their high measurement bandwidth and inherent suitability for wireless readout schemes. The objective of this project is to develop a capacitive pressure sensor based on silicon carbon nitride (SiCN), a new class of high-temperature ceramic materials, which possesses excellent mechanical and electric properties at temperatures up to 1,600 C.

  10. Survival of Escherichia coli O157:H7 in Milk Exposed to High Temperatures and High Pressure**

    Directory of Open Access Journals (Sweden)

    Irena Usajewicz

    2006-01-01

    Full Text Available The objective of the present study was to determine the survival of two enterohemorrhagic Escherichia coli O157:H7 strains (no. 94 and 402 and a saprophytic E. coli 1 strain at temperatures of 55 and 60 °C, and under the pressure of 300 to 600 MPa at ambient temperature (about 20 °C. The strains, in populations of 106–107 CFU/mL, were introduced into the skim milk and broth. The survival of test strains at high temperatures and high pressure depended to a high degree (p<0.05 on the type of medium in which the cells were suspended. At 55 °C the inactivation of E. coli cells was recorded after 60 to 120 min in the broth, and after 180 min in the milk. At 60 °C the time required for their thermal death was 15 to 30 min in broth. In milk only E. coli 1 cells died after 30-minute heating; the other strains survived in populations of about 40 CFU/mL. In the broth, a pressure of 550 MPa, applied for 20 min at ambient temperature, killed the entire populations of E. coli 94 and E. coli 402, and all E. coli 1 cells died at 600 MPa, also applied for 20 min at ambient temperature. In the milk live cells of all pressurized strains survived in the quantities of 102–103 CFU/mL, so their reduction by 5 log cycles was not achieved. Damaged cells were found in the majority of samples exposed to heating and high pressure. These cells did not form colonies on nutrient agar, but were able to repair damage and grow in nutrient broth at 37 °C.

  11. Structural phase transition of BaZrO3 under high pressure

    International Nuclear Information System (INIS)

    Yang, Xue; Li, Quanjun; Liu, Ran; Liu, Bo; Zhang, Huafang; Jiang, Shuqing; Zou, Bo; Cui, Tian; Liu, Bingbing; Liu, Jing

    2014-01-01

    We studied the phase transition behavior of cubic BaZrO 3 perovskite by in situ high pressure synchrotron X-ray diffraction experiments up to 46.4 GPa at room temperature. The phase transition from cubic phase to tetragonal phase was observed in BaZrO 3 for the first time, which takes place at 17.2 GPa. A bulk modulus 189 (26) GPa for cubic BaZrO 3 is derived from the pressure–volume data. Upon decompression, the high pressure phase transforms into the initial cubic phase. It is suggested that the unstable phonon mode caused by the rotation of oxygen octahedra plays a crucial role in the high pressure phase transition behavior of BaZrO 3

  12. The high temperature out-of-pile test of LVDT for internal pressure measurement of nuclear fuel rod

    Energy Technology Data Exchange (ETDEWEB)

    Son, J. M.; Kim, B. K.; Kim, D. S.; Yoon, K. B.; Sin, Y. T.; Park, S. J.; Kang, Y. H. [KAERI, Taejon (Korea, Republic of)

    2002-10-01

    As a part of the development of instrumentation technologies for the nuclear fuel irradiation test in HANARO(High-flux Advanced Nuclear Application Reactor), the internal pressure measurement technique of the nuclear fuel rod is being developed using LVDT(Linear Variable Differential Transformer). As the results of out-of-pile test at room temperature, it was concluded that the well qualified out-of-pile tests were needed to understand the LVDT's detail characteristics at high temperature for the detail design of the fuel irradiation capsule, because LVDT is very sensitive to variation of temperature. Therefore, the high temperature out-of-pile test system for pressure measurement was developed, and this test was performed under the temperature condition between room temperature and 300 .deg. C increasing the pressure from 0 bar to 30 bar. The LVDT's high temperature characteristics and temperature sensitivity of LVDT were analyzed through this experiment. Based on the result of this test, the method for the application of LVDT at high temperature was introduced. It is known that the results will be used to predict accurately the internal pressure of fuel rod during irradiation test.

  13. Low-temperature specific heat of the β-pyrochlore oxide superconductors under high pressure

    Science.gov (United States)

    Isono, T.; Iguchi, D.; Machida, Y.; Izawa, K.; Salce, B.; Flouquet, J.; Ogusu, H.; Yamaura, J.; Hiroi, Z.

    2011-01-01

    We report the results of the low-temperature specific heat measurements of the single crystalline β-pyrochlore oxide superconductors AOs 2O 6 (A=K, Rb, and Cs) under high pressure up to 13 GPa. We find that superconducting transition temperature ( Tc) monotonically increases for CsOs 2O 6 and RbOs 2O 6, while the one for KOs 2O 6 decreases by applying the pressure. With further increasing the pressure, Tc is suddenly suppressed at the same lattice volume for all compounds, concomitant with the first-order structural phase transition.

  14. The effect of pressurization path on high pressure gas forming of Ti-3Al-2.5V at elevated temperature

    OpenAIRE

    Liu Gang; Wang Jianlong; Dang Kexin; Yuan Shijian

    2015-01-01

    High pressure gas forming is a tubular component forming technology with pressurized gas at elevated temperature, based on QPF, HMGF and Hydroforming. This process can be used to form tube blank at lower temperatures with high energy efficiency and also at higher strain rates. With Ti-3Al-2.5V Ti-alloy tube, the potential of HPGF was studied further through experiments at the elevated temperatures of 650 ∘C and 700 ∘C. In order to know the formability of the Ti-alloy tube, tensile tests were ...

  15. Slot Antenna Integrated Re-Entrant Resonator Based Wireless Pressure Sensor for High-Temperature Applications.

    Science.gov (United States)

    Su, Shujing; Lu, Fei; Wu, Guozhu; Wu, Dezhi; Tan, Qiulin; Dong, Helei; Xiong, Jijun

    2017-08-25

    The highly sensitive pressure sensor presented in this paper aims at wireless passive sensing in a high temperature environment by using microwave backscattering technology. The structure of the re-entrant resonator was analyzed and optimized using theoretical calculation, software simulation, and its equivalent lump circuit model was first modified by us. Micro-machining and high-temperature co-fired ceramic (HTCC) process technologies were applied to fabricate the sensor, solving the common problem of cavity sealing during the air pressure loading test. In addition, to prevent the response signal from being immersed in the strong background clutter of the hermetic metal chamber, which makes its detection difficult, we proposed two key techniques to improve the signal to noise ratio: the suppression of strong background clutter and the detection of the weak backscattered signal of the sensor. The pressure sensor demonstrated in this paper works well for gas pressure loading between 40 and 120 kPa in a temperature range of 24 °C to 800 °C. The experimental results show that the sensor resonant frequency lies at 2.1065 GHz, with a maximum pressure sensitivity of 73.125 kHz/kPa.

  16. Combined resistive and laser heating technique for in situ radial X-ray diffraction in the diamond anvil cell at high pressure and temperature

    Energy Technology Data Exchange (ETDEWEB)

    Miyagi, Lowell [Department of Geology and Geophysics, University of Utah, Salt Lake City, Utah 84112 (United States); Department of Earth Sciences, Montana State University, Bozeman, Montana 59717 (United States); Kanitpanyacharoen, Waruntorn; Kaercher, Pamela; Wenk, Hans-Rudolf; Alarcon, Eloisa Zepeda [Department of Earth and Planetary Science, University of California, Berkeley, California 94720 (United States); Raju, Selva Vennila [Advanced Light Source, Lawrence Berkeley Laboratory, Berkeley, California 94720 (United States); HiPSEC, Department of Physics, University of Nevada, Las Vegas, Nevada 89154 (United States); Knight, Jason; MacDowell, Alastair [Advanced Light Source, Lawrence Berkeley Laboratory, Berkeley, California 94720 (United States); Williams, Quentin [Department of Earth and Planetary Science, University of California, Santa Cruz, California 95064 (United States)

    2013-02-15

    To extend the range of high-temperature, high-pressure studies within the diamond anvil cell, a Liermann-type diamond anvil cell with radial diffraction geometry (rDAC) was redesigned and developed for synchrotron X-ray diffraction experiments at beamline 12.2.2 of the Advanced Light Source. The rDAC, equipped with graphite heating arrays, allows simultaneous resistive and laser heating while the material is subjected to high pressure. The goals are both to extend the temperature range of external (resistive) heating and to produce environments with lower temperature gradients in a simultaneously resistive- and laser-heated rDAC. Three different geomaterials were used as pilot samples to calibrate and optimize conditions for combined resistive and laser heating. For example, in Run1, FeO was loaded in a boron-mica gasket and compressed to 11 GPa then gradually resistively heated to 1007 K (1073 K at the diamond side). The laser heating was further applied to FeO to raise temperature to 2273 K. In Run2, Fe-Ni alloy was compressed to 18 GPa and resistively heated to 1785 K (1973 K at the diamond side). The combined resistive and laser heating was successfully performed again on (Mg{sub 0.9}Fe{sub 0.1})O in Run3. In this instance, the sample was loaded in a boron-kapton gasket, compressed to 29 GPa, resistive-heated up to 1007 K (1073 K at the diamond side), and further simultaneously laser-heated to achieve a temperature in excess of 2273 K at the sample position. Diffraction patterns obtained from the experiments were deconvoluted using the Rietveld method and quantified for lattice preferred orientation of each material under extreme conditions and during phase transformation.

  17. High Temperature Characterization of Ceramic Pressure Sensors

    National Research Council Canada - National Science Library

    Fonseca, Michael A; English, Jennifer M; Von Arx, Martin; Allen, Mark G

    2001-01-01

    This work reports functional wireless ceramic micromachined pressure sensors operating at 450 C, with demonstrated materials and readout capability indicating potential extension to temperatures in excess of 600 C...

  18. Optical diagnostics of diesel spray injections and combustion in a high-pressure high-temperature cell

    NARCIS (Netherlands)

    Bougie, H.J.T.; Tulej, M.; Dreier, T.; Dam, N.J.; Meulen, J.J. ter; Gerber, T.

    2005-01-01

    We report on spatially and temporally resolved optical diagnostic measurements of propagation and combustion of diesel sprays introduced through a single-hole fuel injector into a constant volume, high-temperature, high-pressure cell. From shadowgraphy images in non-reacting environments of pure

  19. High-Pressure-High-Temperature Processing Reduces Maillard Reaction and Viscosity in Whey Protein-Sugar Solutions.

    Science.gov (United States)

    Avila Ruiz, Geraldine; Xi, Bingyan; Minor, Marcel; Sala, Guido; van Boekel, Martinus; Fogliano, Vincenzo; Stieger, Markus

    2016-09-28

    The aim of the study was to determine the influence of pressure in high-pressure-high-temperature (HPHT) processing on Maillard reactions and protein aggregation of whey protein-sugar solutions. Solutions of whey protein isolate containing either glucose or trehalose at pH 6, 7, and 9 were treated by HPHT processing or conventional high-temperature (HT) treatments. Browning was reduced, and early and advanced Maillard reactions were retarded under HPHT processing at all pH values compared to HT treatment. HPHT induced a larger pH drop than HT treatments, especially at pH 9, which was not associated with Maillard reactions. After HPHT processing at pH 7, protein aggregation and viscosity of whey protein isolate-glucose/trehalose solutions remained unchanged. It was concluded that HPHT processing can potentially improve the quality of protein-sugar-containing foods, for which browning and high viscosities are undesired, such as high-protein beverages.

  20. Molybdenum cell for x-ray diffraction measurements of fluid alkali metals at high temperatures and high pressures

    Science.gov (United States)

    Matsuda, Kazuhiro; Tamura, Kozaburo; Katoh, Masahiro; Inui, Masanori

    2004-03-01

    We have developed a sample cell for x-ray diffraction measurements of fluid alkali metals at high temperatures and high pressures. All parts of the cell are made of molybdenum which is resistant to the chemical corrosion of alkali metals. Single crystalline molybdenum disks electrolytically thinned down to 40 μm were used as the walls of the cell through which x rays pass. The crystal orientation of the disks was controlled in order to reduce the background from the cell. All parts of the cell were assembled and brazed together using a high-temperature Ru-Mo alloy. Energy dispersive x-ray diffraction measurements have been successfully carried out for fluid rubidium up to 1973 K and 16.2 MPa. The obtained S(Q) demonstrates the applicability of the molybdenum cell to x-ray diffraction measurements of fluid alkali metals at high temperatures and high pressures.

  1. 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.

  2. Experimental study on capacitance void fraction meters for high temperature and high pressure conditions

    International Nuclear Information System (INIS)

    Watanabe, Hironori; Mitsutake, Toru; Shibata, Mitsuhiko; Takase, Kazuyuki

    2010-01-01

    The electro-void fraction meter (Capacitance type meter) was applied to higher pressure conditions of 18 MPa than BWR operating conditions of 7 MPa. The void fraction measurement system has been developed including the electrodes of void fraction measurement, instrumentation cables with mineral insulation and simplified electric circuit to provide good signal-to-noise ratio. It satisfied the performance of thermal and pressure resistance and electric insulating capacity. Calibration function for high temperature and high pressure conditions was confirmed through calibration test with 37-rod bundle against datum 19-rod bundle by the quick-shut valve method respectively under 2 MPa conditions. It was confirmed that the measured data were consistent with those measured by the quick-shut valve method. (author)

  3. High-pressure x-ray diffraction of icosahedral Zr-Al-Ni-Cu-Ag quasicrystals

    DEFF Research Database (Denmark)

    Jiang, Jianzhong; Saksl, Karel; Rasmussen, Helge Kildahl

    2001-01-01

    temperature using synchrotron radiation. The icosahedral quasicrystal structure is retained up to the highest hydrostatic pressure used (approximately 28 GPa) and is reversible after decompression. The bulk modulus at zero pressure and its pressure derivative of the icosahedral Zr-Al-Ni-Cu-Ag quasicrystal......The effect of pressure on the structural stability of icosahedral Zr-Al-Ni-Cu-Ag quasicrystals forming from a Zr65Al7.5Ni10Cu7.5Ag10 metallic glass with a supercooled liquid region of 44 K has been investigated by in situ high-pressure angle-dispersive x-ray powder diffraction at ambient......-Al-Ni-Cu-Ag quasicrystals induced by pressure....

  4. High temperature and high performance light water cooled reactors operating at supercritical pressure, research and development

    International Nuclear Information System (INIS)

    Oka, Y.; Koshizuka, S.; Katsumura, Y.; Yamada, K.; Shiga, S.; Moriya, K.; Yoshida, S.; Takahashi, H.

    2003-01-01

    The concept of supercritical-pressure, once-through coolant cycle nuclear power plant (SCR) was developed at the University of Tokyo. The research and development (R and D) started worldwide. This paper summarized the conceptual design and R and D in Japan. The big advantage of the SCR concept is that the temperatures of major components such as reactor pressure vessel, control rod drive mechanisms, containments, coolant pumps, main steam piping and turbines are within the temperatures of the components of LWR and supercritical fossil fired power plants (FPP) in spite of the high outlet coolant temperature. The experience of these components of LWR and supercritical fossil fired power plants will be fully utilized for SCR. The high temperature, supercritical-pressure light water reactor is the logical evolution of LWR. Boiling evolved from circular boilers, water tube boilers and once-through boilers. It is the reactor version of the once-through boiler. The development from LWR to SCR follows the history of boilers. The goal of the R and D should be the capital cost reduction that cannot be achieved by the improvement of LWR. The reactor can be used for hydrogen production either by catalysis and chemical decomposition of low quality hydrocarbons in supercritical water. The reactor is compatible with tight lattice fast core for breeders due to low outlet coolant density, small coolant flow rate and high head coolant pumps

  5. Fabrication of intermetallic NiAl by self-propagating high-temperature synthesis reaction using aluminium nanopowder under high pressure

    CERN Document Server

    Dong Shu Shan; Cheng Hai Yong; Yang Hai Bin; Zou Guang Tian

    2002-01-01

    By using aluminium nanopowder prepared by wire electrical explosion, pure monophase NiAl compound with fine crystallites (<=10 mu m) and good densification (98% of the theoretical green density) was successfully fabricated by means of self-propagating high-temperature synthesis (SHS) under a high pressure of 50 MPa. Investigation shows that, due to the physical and chemical characteristics of the nanoparticles, the SHS reaction mode and mechanism are distinct from those when using conventional coarse-grained reactants. The SHS reaction process depends on the thermal conditions related to pressure and can occur at a dramatically low temperature of 308 sup o C, which cannot be expected in conventional SHS reaction. With increasing pressure, the SHS explosive ignition temperature (T sub i sub g) of forming NiAl decreases due to thermal and kinetic effects.

  6. Stable and solid pellets of functionalized multi-walled carbon nanotubes produced under high pressure and temperature

    Energy Technology Data Exchange (ETDEWEB)

    Santos, Pâmela Andréa Mantey dos [Universidade Federal do Rio Grande do Sul, UFRGS, Programa de Pós-Graduação em Ciência dos Materiais (Brazil); Gallas, Marcia Russman [Universidade Federal do Rio Grande do Sul, UFRGS, Instituto de Física (Brazil); Radtke, Cláudio; Benvenutti, Edilson Valmir [Universidade Federal do Rio Grande do Sul, UFRGS, Instituto de Química (Brazil); Elias, Ana Laura [The Pennsylvania State University, Department of Physics and Center for 2-D and Layered Materials (United States); Rajukumar, Lakshmy Pulickal [The Pennsylvania State University, Department of Materials Science and Engineering (United States); Terrones, Humberto [Rensselaer Polytechnic Institute, Department of Physics, Applied Physics and Astronomy (United States); Endo, Morinobu [Shinshu University, Carbon Institute of Science and Technology (Japan); Terrones, Mauricio [The Pennsylvania State University, Department of Physics and Center for 2-D and Layered Materials (United States); Costa, Tania Maria Haas, E-mail: taniaha@iq.ufrgs.br, E-mail: taniahac@gmail.com [Universidade Federal do Rio Grande do Sul, UFRGS, Programa de Pós-Graduação em Ciência dos Materiais (Brazil)

    2015-06-15

    High pressure/temperature was applied on samples of pristine multi-walled carbon nanotubes (MWCNT), functionalized nanotubes (f-MWCNT), and nanotubes doped with nitrogen (CN{sub x}MWNT). Cylindrical compact pellets of f-MWCNT with diameters of about 6 mm were obtained under pressure of 4.0 GPa at room temperature and at 400 °C, using graphite as pressure transmitting medium. The best pellet samples were produced using nitric and sulfuric acids for the functionalization of MWCNT. The effect of high pressure/temperature on CNT was investigated by several spectroscopy and characterization techniques, such as Raman spectroscopy, X-ray powder diffraction, X-ray photoelectron spectroscopy, N{sub 2} adsorption/desorption isotherms, and transmission electron microscopy. It was found that MWCNT maintain their main features in the compacted pellets, such as integrity, original morphology, and structure, demonstrating that high-pressure/temperature compaction can indeed be used to fabricate novel CNT self-supported materials. Additionally, the specific surface area and porosity are unchanged, which is important when using bulk CNT in adsorption processes. Raman analysis of the G’-band showed a shift to lower wavenumbers when f-MWCNT were processed under high pressure, suggesting that CNT are under tensile stress.

  7. Experimental on moisture migration and pore pressure formation of concrete members subjected to high temperature

    International Nuclear Information System (INIS)

    Nagao, Kakuhiro; Nakane, Sunao

    1993-01-01

    The experimental studies concerning temperature, moisture migration, and pore pressure of mass concrete mock-up specimens heated up to high temperature at 110degC to 600degC, were performed, so as to correctly estimate the moisture migration behaviour of concrete members subjected to high temperature, which is considered significantly influenced on physical properties of concrete. As a results, it is confirmed that the moisture migration behavior of concrete members can be explained by temperature and pore pressure, and indicate the characteristics both sealed condition (dissipation of moisture is prevented) and unsealed condition (dissipation of moisture occur). (author)

  8. Development of a new micro-furnace for "in situ" high-temperature single crystal X-ray diffraction measurements

    Science.gov (United States)

    Alvaro, Matteo; Angel, Ross J.; Marciano, Claudio; Zaffiro, Gabriele; Scandolo, Lorenzo; Mazzucchelli, Mattia L.; Milani, Sula; Rustioni, Greta; Domeneghetti, Chiara M.; Nestola, Fabrizio

    2015-04-01

    Several experimental methods to reliably determine elastic properties of minerals at non-ambient conditions have been developed. In particular, different techniques for generating high-pressure and high-temperature have been successfully adopted for single-crystal and powder X-ray diffraction measurements. High temperature devices for "in-situ" measurements should provide the most controlled isothermal environment as possible across the entire sample. It is intuitive that in general, thermal gradients across the sample increase as the temperature increases. Even if the small isothermal volume required for single-crystal X-ray diffraction experiments makes such phenomena almost negligible, the design of a furnace should also aim to reduce thermal gradients by including a large thermal mass that encloses the sample. However this solution often leads to complex design that results in a restricted access to reciprocal space or attenuation of the incident or diffracted intensity (with consequent reduction of the accuracy and/or precision in lattice parameter determination). Here we present a newly-developed H-shaped Pt-Pt/Rh resistance microfurnace for in-situ high-temperature single-crystal X-ray diffraction measurements. The compact design of the furnace together with the long collimator-sample-detector distance allows us to perform measurements up to 2θ = 70° with no further restrictions on any other angular movement. The microfurnace is equipped with a water cooling system that allows a constant thermal gradient to be maintained that in turn guarantees thermal stability with oscillations smaller than 5°C in the whole range of operating T of room-T to 1200°C. The furnace has been built for use with a conventional 4-circle Eulerian geometry equipped with point detector and automated with the SINGLE software (Angel and Finger 2011) that allows the effects of crystal offsets and diffractometer aberrations to be eliminated from the refined peak positions by the 8

  9. Stress corrosion cracking of austenitic stainless steel in high temperature and high pressure water

    International Nuclear Information System (INIS)

    Uragami, Ken

    1977-01-01

    Austenitic stainless steels used in for equipment in chemical plants have failed owing to stress corrosion cracking (SCC). These failures brought about great problems in some cases. The failures were caused by chloride, sulfide and alkali solution environment, in particular, by chloride solution environment. It was known that SCC was caused not only by high content chloride solution such as 42% MgCl 2 solution but also by high temperature water containing Cl - ions as NaCl. In order to estimate quantitatively the effects of some factors on SCC in high temperature water environment, the effects of Cl - ion contents, oxygen partial pressure (increasing in proportion to dissolved oxygen), pH and temperature were investigated. Moreover SCC sensitivity owing to the difference of materials and heat treatments was also investigated. The experimental results obtained are summarized as follows: (1) Regarding the effect of contaminant Cl - ions in proportion as Cl - ion contents increased, the material life extremely decreased owing to SCC. The tendency of decreasing was affected by the level of oxygen partial pressure. (2) Three regions of SCC sensitivity existed and they depended upon oxygen partial pressure. These were a region that did not show SCC sensitivity, a region of the highest SCC sensitivity and a region of somewhat lower SCC sensitivity. (3) In the case of SUS304 steel and 500 ppm Cl - ion contents SCC did not occur at 150 0 C, but it occurred and caused failures at 200 0 C and 250 0 C. (auth.)

  10. Hypertension (High Blood Pressure)

    Science.gov (United States)

    ... Safe Videos for Educators Search English Español Hypertension (High Blood Pressure) KidsHealth / For Teens / Hypertension (High Blood Pressure) What's ... rest temperature diet emotions posture medicines Why Is High Blood Pressure Bad? High blood pressure means a person's heart ...

  11. In situ Raman study of C60 polymerization during isothermal pressurizing at 800 K

    International Nuclear Information System (INIS)

    Talyzin, A V; Dubrovinsky, L S

    2004-01-01

    The first in situ Raman study of C 60 isothermal compression at 800 K and up to 32 GPa was performed using rhombohedral and tetragonal phases as starting materials. The rhombohedral phase shows a phase transition to 3D polymer above 10 GPa, similar to that in experiments where isobaric heating was used at pressures of 9-13 GPa. It is shown that the T-P diagram of C 60 polymeric phases (temperature increase followed by pressurizing) is significantly different from the known P-T diagram (pressurizing followed by heating). Tetragonal polymer exhibited significantly stronger stability and can be followed at least up to ∼15 GPa. Heating up to 800 K of tetragonal polymer at pressures of 6-8 GPa confirms that, due to geometrical frustrations, the tetragonal phase remains stable even at pressure and temperature conditions at which rhombohedral polymer is usually formed

  12. Energy-Based Tetrahedron Sensor for High-Temperature, High-Pressure Environments

    Science.gov (United States)

    Gee, Kent L.; Sommerfeldt, Scott D.; Blotter, Jonathan D.

    2012-01-01

    An acoustic energy-based probe has been developed that incorporates multiple acoustic sensing elements in order to obtain the acoustic pressure and three-dimensional acoustic particle velocity. With these quantities, the user can obtain various energy-based quantities, including acoustic energy density, acoustic intensity, and acoustic impedance. In this specific development, the probe has been designed to operate in an environment characterized by high temperatures and high pressures as is found in the close vicinity of rocket plumes. Given these capabilities, the probe is designed to be used to investigate the acoustic conditions within the plume of a rocket engine or jet engine to facilitate greater understanding of the noise generation mechanisms in those plumes. The probe features sensors mounted inside a solid sphere. The associated electronics for the probe are contained within the sphere and the associated handle for the probe. More importantly, the design of the probe has desirable properties that reduce the bias errors associated with determining the acoustic pressure and velocity using finite sum and difference techniques. The diameter of the probe dictates the lower and upper operating frequencies for the probe, where accurate measurements can be acquired. The current probe design implements a sphere diameter of 1 in. (2.5 cm), which limits the upper operating frequency to about 4.5 kHz. The sensors are operational up to much higher frequencies, and could be used to acquire pressure data at higher frequencies, but the energy-based measurements are limited to that upper frequency. Larger or smaller spherical probes could be designed to go to lower or higher frequency range

  13. PREFACE: Rheology and Elasticity Studies at Ultra-High Pressures and Temperatures

    Science.gov (United States)

    Liu, Haozhe; Wenk, Hans-Rudolf; Duffy, Thomas S.

    2006-06-01

    One of the major goals of geophysical research is to understand deformation in the deep Earth. The COMPRES (Consortium for Materials Properties Research in Earth Sciences) workshop on `Rheology and Elasticity Studies at Ultra-High Pressures and Temperatures' was held on 21-23 October 2005 at the Advanced Photon Source, Argonne National Laboratory, organized by Haozhe Liu, Hans-Rudolf Wenk and Thomas S Duffy, and provided an opportunity to assemble more than 50 scientists from six countries. Experts in diamond anvil cell (DAC) design, large-volume high-pressure apparatus and data analysis defined the current state of ultra-high pressure deformation studies and explored initiatives to push the technological frontier. The DAC, when used in radial diffraction geometry, emerges as a powerful tool for investigation of plasticity and elasticity of materials at high pressures. More information regarding this workshop can be found at the website: http://www.hpcat.aps.anl.gov/Hliu/Workshop/Index1.htm. In this special issue of Journal of Physics: Condensed Matter, 17 manuscripts review the state-of-the-art and we hope they will stimulate researchers to participate in this field and take it forward to a new level. A major incentive for high-pressure research has been the need of geophysicists to understand composition, physical properties and deformation in the deep Earth in order to interpret the macroscopically observed seismic anisotropy. In the mantle and core, materials deform largely in a ductile manner at low stresses and strain rates. From observational inferences and experiments at lower pressures, it is considered plausible that deformation occurs in the field of dislocation creep or diffusion creep and deformation mechanisms depend in a complex way on stress, strain rate, pressure, temperature, grain size and hydration state. With novel apparatus such as the rotational Drickamer press or deformation DIA (D-DIA) multianvil apparatus, large volumes (approximately 10

  14. A prestressed concrete pressure vessel for helium high temperature reactor system

    International Nuclear Information System (INIS)

    Horner, R.M.W.; Hodzic, A.

    1976-01-01

    A novel prestressed concrete pressure vessel has been developed to provide the primary containment for a fully integrated system comprising a high temperature nuclear reactor, three horizontally mounted helium turbines, associated heat exchangers and inter-connecting ducts. The design and analysis of the pressure vessel is described. Factors affecting the final choice of layout are discussed, and earlier development work seeking to resolve the conflicting requirements of the structural, mechanical, and system engineers outlined. Proposals to increase the present output of about 1000 MW of electrical power to over 3000 MW, by incorporating four turbines in a single pressure vessel are presented. (author)

  15. Speciation in Aqueous MgSO4 Fluid at High Pressures and Temperatures Studied by First-Principles Modeling and Raman Spectroscopy

    Science.gov (United States)

    Jahn, S.; Schmidt, C.

    2008-12-01

    Aqueous fluids play an essential role in mass and energy transfer in the lithosphere. Their presence has also a large effect on physical properties of rocks, e.g. the electrical conductivity. Many chemical and physical properties of aqueous fluids strongly depend on the speciation, but very little is known about this fundamental parameter at high pressures and temperatures, e.g. at subduction zone conditions. Here we use a combined approach of first-principles molecular dynamics simulation and Raman spectroscopy to study the molecular structure of aqueous 2~mol/kg MgSO4 fluids up to pressures of 3~GPa and temperatures of 750~°C. MgSO4-H2O is selected as a model system for sulfate bearing subduction zone fluids. The simulations are performed using Car-Parrinello dynamics, a system size of 120 water and four MgSO4 molecules with production runs of at least 10~ps at each P and T. Raman spectra were obtained in situ using a Bassett-type hydrothermal diamond anvil cell with external heating. Both simulation and spectroscopic data show a dynamic co-existence of various associated molecular species as well as dissociated Mg2+ and SO42- in the single phase fluid. Fitting the Raman signal in the frequency range of the ν1-SO42- stretching mode yields the P-T dependence of the relative proportions of different peaks. The latter can be assigned to species based on literature data and related to the species found in the simulation. The dominant associated species found in the P-T range of interest here are Mg-SO4 ion pairs with one (monodentate) and two (bidentate) binding sites. At the highest P and T, an additional peak is identified. At low pressures and high temperature (T>230~°C), kieserite, MgSO4·H2O, nucleated in the experiment. At the same conditions the simulations show a clustering of Mg, which is interpreted as a precursor of precipitation. In conclusion, the speciation of aqueous MgSO4 fluid shows a complex behavior at high P and T that cannot be extrapolated

  16. 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.

  17. Raman scattering of 2H-MoS2 at simultaneous high temperature and high pressure (up to 600 K and 18.5 GPa

    Directory of Open Access Journals (Sweden)

    JianJun Jiang

    2016-03-01

    Full Text Available The Raman spectroscopy of natural molybdenite powder was investigated at simultaneous conditions of high temperature and high pressure in a heatable diamond anvil cell (DAC, to obtain the temperature and pressure dependence of the main Raman vibrational modes (E1g, E 2 g 1 ,A1g, and 2LA(M. Over our experimental temperature and pressure range (300–600 K and 1 atm−18.5 GPa, the Raman modes follow a systematic blue shift with increasing pressure, and red shift with increasing temperature. The results were calculated by three-variable linear fitting. The mutual correlation index of temperature and pressure indicates that the pressure may reduce the temperature dependence of Raman modes. New Raman bands due to structural changes emerged at about 3–4 GPa lower than seen in previous studies; this may be caused by differences in the pressure hydrostaticity and shear stress in the sample cell that promote the interlayer sliding.

  18. Raman scattering of 2H-MoS2 at simultaneous high temperature and high pressure (up to 600 K and 18.5 GPa)

    Science.gov (United States)

    Jiang, JianJun; Li, HePing; Dai, LiDong; Hu, HaiYing; Zhao, ChaoShuai

    2016-03-01

    The Raman spectroscopy of natural molybdenite powder was investigated at simultaneous conditions of high temperature and high pressure in a heatable diamond anvil cell (DAC), to obtain the temperature and pressure dependence of the main Raman vibrational modes (E1g, E2 g 1 ,A1g, and 2LA(M)). Over our experimental temperature and pressure range (300-600 K and 1 atm-18.5 GPa), the Raman modes follow a systematic blue shift with increasing pressure, and red shift with increasing temperature. The results were calculated by three-variable linear fitting. The mutual correlation index of temperature and pressure indicates that the pressure may reduce the temperature dependence of Raman modes. New Raman bands due to structural changes emerged at about 3-4 GPa lower than seen in previous studies; this may be caused by differences in the pressure hydrostaticity and shear stress in the sample cell that promote the interlayer sliding.

  19. Low temperature and high pressure crystals of room temperature ionic liquid: N, N-diethyl-N-methyl-N-(2-methoxyethyl) ammonium tetrafluoroborate

    International Nuclear Information System (INIS)

    Abe, Hiroshi; Imai, Yusuke; Takekiyo, Takahiro; Yoshimura, Yukihiro; Hamaya, Nozomu

    2014-01-01

    Crystals of room temperature ionic liquid (RTIL) are obtained separately at low temperature or under high pressure. The RTIL is N, N-diethyl-N-methyl-N-(2-methoxyethyl) ammonium tetrafluoroborate, [DEME][BF 4 ]. At ambient pressure, low-temperature (LT) crystals appeared on slow cooling. By simultaneous X-ray diffraction and differential scanning calorimetry (DSC) measurements, metastable monoclinic and stable orthorhombic phases coexist in pure [DEME][BF 4 ]. Furthermore, the DSC thermal trace indicates that the metastable monoclinic phase was stabilized by adding water. In contrast, on compression process up to 7.6 GPa, crystallization is completely suppressed even upon slow compression. Direct observations using optical microscopy also support no crystal domain growth on compression process. High-pressure (HP) crystals at room temperature were seen only on decompression process, where two different kinds of crystals appeared subsequently. By crystal structure analysis, the LT crystal structures have no relation with the HP ones. Moreover, both metastable monoclinic phase at low temperature and higher pressure crystal has a folding molecular conformation and anti-parallel pairing of the [DEME] cation as the instability factors

  20. Hydrogen/Oxygen Reactions at High Pressures and Intermediate Temperatures: Flow Reactor Experiments and Kinetic Modeling

    DEFF Research Database (Denmark)

    Hashemi, Hamid; Christensen, Jakob Munkholt; Glarborg, Peter

    A series of experimental and numerical investigations into hydrogen oxidation at high pressures and intermediate temperatures has been conducted. The experiments were carried out in a high pressure laminar flow reactor at 50 bar pressure and a temperature range of 600–900 K. The equivalence ratio......, the mechanism is used to simulate published data on ignition delay time and laminar burning velocity of hydrogen. The flow reactor results show that at reducing, stoichiometric, and oxidizing conditions, conversion starts at temperatures of 750–775 K, 800–825 K, and 800–825 K, respectively. In oxygen atmosphere......, ignition occurs at the temperature of 775–800 K. In general, the present model provides a good agreement with the measurements in the flow reactor and with recent data on laminar burning velocity and ignition delay time....

  1. Study of the effect of pressure on electrolysis of H2O and co-electrolysis of H2O and CO2 at high temperature

    International Nuclear Information System (INIS)

    Bernadet, Lucile

    2016-01-01

    This thesis work investigates the behavior of a solid oxide cell operating under pressure in high temperature steam electrolysis and co-electrolysis mode (H 2 O and CO 2 ). The experimental study of single cell associated with the development of multi-physical models have been set up. The experiments, carried out using an original test bench developed by the CEA-Grenoble on two types of cells between 1 and 10 bar and 700 to 800 C, allowed to identify in both operating modes that the pressure has a positive or negative effect on performance depending on the cell operating point (current, voltage). In addition, gas analyzes performed in co-electrolysis led to detect in situ CH 4 production under pressure. These pressure effects were simulated by models calibrated at atmospheric pressure. Simulations analysis helped identify the pressure dependent mechanisms and propose operating conditions thanks to the establishment of operating maps. (author) [fr

  2. Startup of a high-temperature reactor cooled and moderated by supercritical-pressure light water

    International Nuclear Information System (INIS)

    Yi, Tin Tin; Ishiwatari, Yuki; Koshizuka, Seiichi; Oka, Yoshiaki

    2003-01-01

    The startup schemes of high-temperature reactors cooled and moderated by supercritical pressure light water (SCLWR-H) with square lattice and descending flow type water rods are studied by thermal-hydraulic analysis. In this study, two kinds of startup systems are investigated. In the constant pressure startup system, the reactor starts at a supercritical pressure. A flash tank and pressure reducing valves are necessary. The flash tank is designed so that the moisture content in the steam is less than 0.1%. In sliding pressure startup system, the reactor starts at a subcritical pressure. A steam-water separator and a drain tank are required for two-phase flow at startup. The separator is designed by referring to the water separator used in supercritical fossil-fired power plants. The maximum cladding surface temperature during the power-raising phase of startup is restricted not to exceed the rated value of 620degC. The minimum feedwater flow rate is 25% for constant pressure startup and 35% for sliding pressure startup system. It is found that both constant pressure startup system and sliding pressure startup system are feasible in SCLWR-H from the thermal hydraulic point of view. The core outlet temperature as high as 500degC can be achieved in the present design of SCLWR-H. Since the feedwater flow rate of SCLWR-H (1190 kg/s) is lower than that of the previous SCR designs the weight of the component required for startup is reduced. The sliding pressure startup system is better than constant pressure startup system in order to reduce the required component weight (and hence material expenditure) and to simplify the startup plant system. (author)

  3. 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.

  4. 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.

  5. Path Dependency of High Pressure Phase Transformations

    Science.gov (United States)

    Cerreta, Ellen

    2017-06-01

    At high pressures titanium and zirconium are known to undergo a phase transformation from the hexagonal close packed (HCP), alpha-phase to the simple-hexagonal, omega-phase. Under conditions of shock loading, the high-pressure omega-phase can be retained upon release. It has been shown that temperature, peak shock stress, and texture can influence the transformation. Moreover, under these same loading conditions, plastic processes of slip and twinning are also affected by similar differences in the loading path. To understand this path dependency, in-situ velocimetry measurements along with post-mortem metallographic and neutron diffraction characterization of soft recovered specimens have been utilized to qualitatively understand the kinetics of transformation, quantify volume fraction of retained omega-phase and characterize the shocked alpha and omega-phases. Together the work described here can be utilized to map the non-equilibrium phase diagram for these metals and lend insight into the partitioning of plastic processes between phases during high pressure transformation. In collaboration with: Frank Addesssio, Curt Bronkhorst, Donald Brown, David Jones, Turab Lookman, Benjamin Morrow, Carl Trujillo, Los Alamos National Lab.; Juan Pablo Escobedo-Diaz, University of New South Wales; Paulo Rigg, Washington State University.

  6. The influence of high pressure and high temperature on the structure of ZrO sub 2 nanosolids

    CERN Document Server

    Xu Da Peng; LiuShue; Wang Quan Yong; Su Wen Hui

    2002-01-01

    Using nanoparticles of ZrO sub 2 (disordered structure) prepared by the method of precipitation as starting materials, ZrO sub 2 nanosolids have been synthesized under different pressures and at different temperatures. The x-ray diffraction results show that the crystallization temperature of the nanoparticles and the temperature at which the structural cubic-monoclinic transformation occurs are obviously reduced for the nanosolids synthesized under high pressure. X-ray photoelectron spectroscopy and EPR measurements indicate that there are some Zr sup 3 sup + ions in nanosolids. With increasing pressure, the number of Zr sup 3 sup + ions in the nanosolids essentially does not vary, and yet the content of oxygen ions with unsaturated bonds and dangling bonds in the interfacial region gradually decreases. The effect of synthesis pressure on the structure and interface states is mainly due to the decrease of the interatomic distance and the increasing interdiffusion of atoms in the interface phase.

  7. High-pressure U3O8 with the fluorite-type structure

    International Nuclear Information System (INIS)

    Zhang, F.X.; Lang, M.; Wang, J.W.; Li, W.X.; Sun, K.; Prakapenka, V.; Ewing, R.C.

    2014-01-01

    A new high-pressure phase of U 3 O 8 , which has a fluorite-type structure, forms at pressures greater than ∼8.1 GPa that was confirmed by in situ x-ray diffraction (XRD) measurements. The fluorite-type U 3 O 8 is stable at pressures at least up to ∼40 GPa and temperatures to 1700 K, and quenchable to ambient conditions. Based on the XRD analysis, there is a huge volume collapse (>20%) for U 3 O 8 during the phase transition and the quenched high-pressure phase is 28% denser than the initial orthorhombic phase at ambient conditions. The high-pressure phase has a very low compressibility comparing with the starting orthorhombic phase. - Graphical abstract: α-U 3 O 8 is in a layered structure with orthorhombic symmetry, at high pressures, it transformed to a fluorite-type cubic structure. There are a lot of defects in the cubic structure, and it is a new kind of hyperstoichiometric uranium oxide, which is stable at ambient conditions. - Highlights: • A new fluorite-type high-pressure phase was found in hyperstoichometric UO 2 +x (x∼0.8). • The new high-pressure structure is quenchable to ambient conditions. • Pressure driven phase transition in orthorhombic U 3 O 8 was first found

  8. Thermoset recycling via high-pressure high-temperature sintering: Revisiting the effect of interchange chemistry

    Science.gov (United States)

    Morin, Jeremy Edward

    In 1844 Charles Goodyear obtained U.S. Patent #3,633 for his "Gum Elastic Composition". In a published circular, which describes his patent for the sulfur vulcanization of gum elastic composition, he stated: "No degree of heat, without blaze, can melt it (rubber)... It resists the most powerful chemical reagents. Aquafortis (nitric acid), sulphuric acid, essential and common oils, turpentine and other solvents... ..." Goodyear's sulfur vulcanization of rubber fueled much of the industrial revolution and made transportation possible, as it exists today. In doing so, Goodyear created one of the most difficult materials to recycle. Rubber will not melt, dissolve, or lend itself to the usual methods of chemical decomposition. Ironically, Goodyear recognized this problem and in 1853 he patented the process of adding ground rubber to virgin material, now currently known as regrind blending. Today, scrap tires represent one of the most serious sources of pollution in the world. Studies estimate that there are roughly 2 billion scrap tires in U.S. landfills and more are being added at a rate of over 273 million tires per year. Current methods of recycling waste tires are crude, ineffective, and use rubber powder as a low cost filler instead of a new rubber. The groundwork for a very simple and effective method of producing high-quality rubber goods using 100% scrap rubber was discovered in 1944 by A. V. Tobolsky et al. This application, however, was not recognized until recently in our laboratory. The process as studied to date represents a method of creating quality, high-value added rubber goods with nothing other than heat and pressure. High pressure is required to obtain a void-free compaction of the rubber particles by forcing all of the free surfaces into intimate contact. High temperature then activates the chemical rearrangement, scission, and reformation of the chemical bonds thus providing new bridges between the once fractured interfaces. This occurs both within

  9. Ultrasonic and metallographic studies on AISI 4140 steel exposed to hydrogen at high pressure and temperature

    Science.gov (United States)

    Oruganti, Malavika

    This thesis conducts an investigation to study the effects of hydrogen exposure at high temperature and pressure on the behavior of AISI 4140 steel. Piezoelectric ultrasonic technique was primarily used to evaluate surface longitudinal wave velocity and defect geometry variations, as related to time after exposure to hydrogen at high temperature and pressure. Critically refracted longitudinal wave technique was used for the former and pulse-echo technique for the latter. Optical microscopy and scanning electron microscopy were used to correlate the ultrasonic results with the microstructure of the steel and to provide better insight into the steel behavior. The results of the investigation indicate that frequency analysis of the defect echo, determined using the pulse-echo technique at regular intervals of time, appears to be a promising tool for monitoring defect growth induced by a high temperature and high pressure hydrogen-related attack.

  10. High-Temperature Tensile and Tribological Behavior of Hybrid (ZrB2+Al3Zr)/AA5052 In Situ Composite

    Science.gov (United States)

    Gautam, G.; Kumar, N.; Mohan, A.; Gautam, R. K.; Mohan, S.

    2016-09-01

    During service life, components such as piston, cylinder blocks, brakes, and discs/drums, have to work under high-temperature conditions. In order to have appropriate material for such applications high-temperature studies are important. Hybrid (ZrB2+Al3Zr)/AA5052 in situ composite has been investigated from ambient to 523 K (250 °C) at an interval of 50 deg. (ZrB2+Al3Zr)/AA5052 in situ composite has been fabricated by the direct melt reaction of AA5052 alloy with zirconium and boron salts. Microstructure studies show refinement in the grain size of base alloy on in situ formation of reinforcement particles. Al3Zr particles are observed in rectangular and polyhedron shapes. It is observed from the tensile studies that ultimate tensile strength, yield strength, and percentage elongation decrease with increase in test temperature. Similar kind of behavior is also observed for flow curve properties. The tensile results have also been correlated with fractography. Wear and friction results indicate that the wear rate increases with increase in normal load, whereas coefficient of friction shows decreasing trend. With increasing test temperature, wear rate exhibits a typical phenomenon. After an initial increase, wear rate follows a decreasing trend up to 423 K (150 °C), and finally a rapid increase is observed, whereas coefficient of friction increases continuously with increase in test temperature. The mechanisms responsible for the variation of wear and friction with different temperatures have been discussed in detail with the help of worn surfaces studies under scanning electron microscope (SEM) & 3D-profilometer and debris analysis by XRD.

  11. Experimental in situ investigations of turbulence under high pressure.

    Science.gov (United States)

    Song, Kwonyul; Al-Salaymeh, Ahmed; Jovanovic, Jovan; Rauh, Cornelia; Delgado, Antonio

    2010-02-01

    In tube injection systems applied in high-pressure processing of packed biomaterials and foods, the pressure-transmitting medium is injected into the vessel to increase the pressure up to 1000 MPa, generating a submerged liquid-free jet. The presence of a turbulent-free jet during the pressurization phase and its positive influence on the homogeneity of the product treatment has already been examined by computational fluid dynamics investigations. However, no experimental data have supported the existence and properties of turbulent flow under high-pressure (HP) conditions up to 400 MPa. This contribution presents the development of two experimental setups: HP-laser Doppler anemometry and HP-hot wire anemometry. For the first time the time-averaged velocity profiles of a free jet during pressurization up to 300 MPa at different Reynolds numbers (Re) have been obtained. In this article, the dependence of the velocity profiles on the Re is discussed in detail. Moreover, the relaminarization phenomenon of the turbulent pipe flow most likely caused by the compressibility effects and viscosity changes of the pressure-transmitting medium is examined.

  12. High pressure in-situ X-ray diffraction study on Zn-doped magnetite nanoparticles

    Science.gov (United States)

    Ferrari, S.; Bilovol, V.; Pampillo, L. G.; Grinblat, F.; Errandonea, D.

    2018-03-01

    We have performed high pressure synchrotron X-ray powder diffraction experiments on two different samples of Zn-doped magnetite nanoparticles (formula Fe(3-x)ZnxO4; x = 0.2, 0.5). The structural behavior of then a noparticles was studied up to 13.5 GPa for x = 0.2, and up to 17.4 GPa for x = 0.5. We have found that both systems remain in the cubic spinel structure as expected for this range of applied pressures. The analysis of the unit cell volume vs. pressure results in bulk modulus values lower than in both end-members, magnetite (Fe3O4) and zinc ferrite (ZnFe2O4), suggesting that chemical disorder may favor compressibility, which is expected to improve the increase of the Neel temperature under compression.

  13. Risk Associated With The Decompression Of High Pressure High Temperature Fluids - Study On Black Oil

    DEFF Research Database (Denmark)

    Figueroa, D. C.; Fosbøl, P. L.; Thomsen, K.

    2015-01-01

    Fluids produced from deep underground reservoirs may result in exponential increase in temperature. It is a consequence of adiabatic fluid decompression from the inverse Joule Thomson Effect (JTE). The phenomenon requires analysis in order to avoid any operational risks. This study evaluates...... the JTE upon decompression of black oil in high pressure-high temperature reservoirs. Also the effect caused by the presence of water and brine on the black oil is studied. The final temperature is calculated from the corresponding energy balance at isenthalpic and non-isenthalpic conditions. It is found...... that the final temperature of black oil increases upon adiabatic decompression. In the case of the isenthalpic process at initial conditions of the reservoir, e.g. 150°C and 1000 bars, it is found that the final temperature can increase to 173.7°C. At non-isenthalpic conditions the final temperature increases...

  14. Wireless Capacitive Pressure Sensor With Directional RF Chip Antenna for High Temperature Environments

    Science.gov (United States)

    Scardelletti, M. C.; Jordan, J. L.; Ponchak, G. E.; Zorman, C. A.

    2015-01-01

    This paper presents the design, fabrication and characterization of a wireless capacitive pressure sensor with directional RF chip antenna that is envisioned for the health monitoring of aircraft engines operating in harsh environments. The sensing system is characterized from room temperature (25 C) to 300 C for a pressure range from 0 to 100 psi. The wireless pressure system consists of a Clapp-type oscillator design with a capacitive MEMS pressure sensor located in the LC-tank circuit of the oscillator. Therefore, as the pressure of the aircraft engine changes, so does the output resonant frequency of the sensing system. A chip antenna is integrated to transmit the system output to a receive antenna 10 m away.The design frequency of the wireless pressure sensor is 127 MHz and a 2 increase in resonant frequency over the temperature range of 25 to 300 C from 0 to 100 psi is observed. The phase noise is less than minus 30 dBcHz at the 1 kHz offset and decreases to less than minus 80 dBcHz at 10 kHz over the entire temperature range. The RF radiation patterns for two cuts of the wireless system have been measured and show that the system is highly directional and the MEMS pressure sensor is extremely linear from 0 to 100 psi.

  15. 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.

  16. 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.)

  17. A high-throughput platform for low-volume high-temperature/pressure sealed vessel solvent extractions

    Energy Technology Data Exchange (ETDEWEB)

    Damm, Markus [Christian Doppler Laboratory for Microwave Chemistry (CDLMC) and Institute of Chemistry, Karl-Franzens-University Graz, Heinrichstrasse 28, A-8010 Graz (Austria); Kappe, C. Oliver, E-mail: oliver.kappe@uni-graz.at [Christian Doppler Laboratory for Microwave Chemistry (CDLMC) and Institute of Chemistry, Karl-Franzens-University Graz, Heinrichstrasse 28, A-8010 Graz (Austria)

    2011-11-30

    Highlights: Black-Right-Pointing-Pointer Parallel low-volume coffee extractions in sealed-vessel HPLC/GC vials. Black-Right-Pointing-Pointer Extractions are performed at high temperatures and pressures (200 Degree-Sign C/20 bar). Black-Right-Pointing-Pointer Rapid caffeine determination from the liquid phase. Black-Right-Pointing-Pointer Headspace analysis of volatiles using solid-phase microextraction (SPME). - Abstract: A high-throughput platform for performing parallel solvent extractions in sealed HPLC/GC vials inside a microwave reactor is described. The system consist of a strongly microwave-absorbing silicon carbide plate with 20 cylindrical wells of appropriate dimensions to be fitted with standard HPLC/GC autosampler vials serving as extraction vessels. Due to the possibility of heating up to four heating platforms simultaneously (80 vials), efficient parallel analytical-scale solvent extractions can be performed using volumes of 0.5-1.5 mL at a maximum temperature/pressure limit of 200 Degree-Sign C/20 bar. Since the extraction and subsequent analysis by either gas chromatography or liquid chromatography coupled with mass detection (GC-MS or LC-MS) is performed directly from the autosampler vial, errors caused by sample transfer can be minimized. The platform was evaluated for the extraction and quantification of caffeine from commercial coffee powders assessing different solvent types, extraction temperatures and times. For example, 141 {+-} 11 {mu}g caffeine (5 mg coffee powder) were extracted during a single extraction cycle using methanol as extraction solvent, whereas only 90 {+-} 11 were obtained performing the extraction in methylene chloride, applying the same reaction conditions (90 Degree-Sign C, 10 min). In multiple extraction experiments a total of {approx}150 {mu}g caffeine was extracted from 5 mg commercial coffee powder. In addition to the quantitative caffeine determination, a comparative qualitative analysis of the liquid phase coffee

  18. A high-throughput platform for low-volume high-temperature/pressure sealed vessel solvent extractions

    International Nuclear Information System (INIS)

    Damm, Markus; Kappe, C. Oliver

    2011-01-01

    Highlights: ► Parallel low-volume coffee extractions in sealed-vessel HPLC/GC vials. ► Extractions are performed at high temperatures and pressures (200 °C/20 bar). ► Rapid caffeine determination from the liquid phase. ► Headspace analysis of volatiles using solid-phase microextraction (SPME). - Abstract: A high-throughput platform for performing parallel solvent extractions in sealed HPLC/GC vials inside a microwave reactor is described. The system consist of a strongly microwave-absorbing silicon carbide plate with 20 cylindrical wells of appropriate dimensions to be fitted with standard HPLC/GC autosampler vials serving as extraction vessels. Due to the possibility of heating up to four heating platforms simultaneously (80 vials), efficient parallel analytical-scale solvent extractions can be performed using volumes of 0.5–1.5 mL at a maximum temperature/pressure limit of 200 °C/20 bar. Since the extraction and subsequent analysis by either gas chromatography or liquid chromatography coupled with mass detection (GC–MS or LC–MS) is performed directly from the autosampler vial, errors caused by sample transfer can be minimized. The platform was evaluated for the extraction and quantification of caffeine from commercial coffee powders assessing different solvent types, extraction temperatures and times. For example, 141 ± 11 μg caffeine (5 mg coffee powder) were extracted during a single extraction cycle using methanol as extraction solvent, whereas only 90 ± 11 were obtained performing the extraction in methylene chloride, applying the same reaction conditions (90 °C, 10 min). In multiple extraction experiments a total of ∼150 μg caffeine was extracted from 5 mg commercial coffee powder. In addition to the quantitative caffeine determination, a comparative qualitative analysis of the liquid phase coffee extracts and the headspace volatiles was performed, placing special emphasis on headspace analysis using solid-phase microextraction (SPME

  19. Superconducting critical temperature under pressure

    Science.gov (United States)

    González-Pedreros, G. I.; Baquero, R.

    2018-05-01

    The present record on the critical temperature of a superconductor is held by sulfur hydride (approx. 200 K) under very high pressure (approx. 56 GPa.). As a consequence, the dependence of the superconducting critical temperature on pressure became a subject of great interest and a high number of papers on of different aspects of this subject have been published in the scientific literature since. In this paper, we calculate the superconducting critical temperature as a function of pressure, Tc(P), by a simple method. Our method is based on the functional derivative of the critical temperature with the Eliashberg function, δTc(P)/δα2F(ω). We obtain the needed coulomb electron-electron repulsion parameter, μ*(P) at each pressure in a consistent way by fitting it to the corresponding Tc using the linearized Migdal-Eliashberg equation. This method requires as input the knowledge of Tc at the starting pressure only. It applies to superconductors for which the Migdal-Eliashberg equations hold. We study Al and β - Sn two weak-coupling low-Tc superconductors and Nb, the strong coupling element with the highest critical temperature. For Al, our results for Tc(P) show an excellent agreement with the calculations of Profeta et al. which are known to agree well with experiment. For β - Sn and Nb, we found a good agreement with the experimental measurements reported in several works. This method has also been applied successfully to PdH elsewhere. Our method is simple, computationally light and gives very accurate results.

  20. A DLTS study of the evolution of oxygen precipitates in Si at high temperature and high pressure

    International Nuclear Information System (INIS)

    Antonova, I.V.; Popov, V.P.; Fedina, L.I.; Shaimeev, S.S.; Misiuk, A.

    1996-01-01

    The effect of high hydrostatic pressure on the dissolution of oxygen precipitates introduced beforehand into Si at temperatures of 920-1000 K (over period of 96 h) is investigated by the DLTS method. A measurement procedure, based on the formation of electrically active complexes (interstitial oxygen atom-vacancy) during electron irradiation of the samples, is proposed. It is shown that the precipitates do not decompose when point defects are introduced at room temperature. As the treatment temperature increases (to 1220-1650 K), for the same values of the hydrostatic pressure (up to 1.3 GPa) the intensity of the decomposition of oxygen precipitates increases and at 1650 K they are completely dissolved. Study of the decomposition kinetics showed that hydrostatic pressure raises the limit of solubility of the oxygen atoms Oi and slows down their diffusion. It is determined that the diffusion activation energy Ea, just as the preexponential factor D0, in the expression for the diffusion decrease with increasing hydrostatic pressure, resulting in a lower diffusion. Possible mechanisms for the effect of hydrostatic pressure on oxygen diffusion near a precipitate are discussed

  1. Laser-Doppler vibrating tube densimeter for measurements at high temperatures and pressures

    International Nuclear Information System (INIS)

    Aida, Tsutomu; Yamazaki, Ai; Akutsu, Makoto; Ono, Takumi; Kanno, Akihiro; Hoshina, Taka-aki; Ota, Masaki; Watanabe, Masaru; Sato, Yoshiyuki; Smith, Richard L. Jr.; Inomata, Hiroshi

    2007-01-01

    A laser-Doppler vibrometer was used to measure the vibration of a vibrating tube densimeter for measuring P-V-T data at high temperatures and pressures. The apparatus developed allowed the control of the residence time of the sample so that decomposition at high temperatures could be minimized. A function generator and piezoelectric crystal was used to excite the U-shaped tube in one of its normal modes of vibration. Densities of methanol-water mixtures are reported for at 673 K and 40 MPa with an uncertainty of 0.009 g/cm 3

  2. Required developments towards ultra high pressure and temperature subsea tree system solutions

    Energy Technology Data Exchange (ETDEWEB)

    Queseth, Per-Olaf

    2010-07-01

    For the subsea High Pressure High Temperature oil and gas production systems, the primary challenge is to provide good, reliable solutions for HPHT reservoir exploitation based on an overview of parameters for already discovered potential fields. The paper will present a resume of Aker Solutions' previous development in this area exemplified with experiences from testing and operator observations during production start of HPHT fields in the North Sea. Further improvements are required to comply with the extreme pressures and temperatures sought to overcome. 'The Devil is in the details' is a very relevant proverb. A program to qualify subsea production X-mas trees for Ultra HPHT use will be presented with highlight on sealing systems, feed-through solutions and materials as well as impact on interfacing systems. Preliminary and intermediate analytical and test results will be presented and remaining activities summarised. (Author)

  3. In situ characterization of the nitridation of dysprosium during mechanochemical processing

    Energy Technology Data Exchange (ETDEWEB)

    Jaques, Brian J.; Osterberg, Daniel D.; Alanko, Gordon A.; Tamrakar, Sumit; Smith, Cole R.; Hurley, Michael F.; Butt, Darryl P., E-mail: DarrylButt@BoiseState.edu

    2015-01-15

    Highlights: • A nitridation reaction in a high energy planetary ball mill was monitored in situ. • Dysprosium mononitride was synthesized from Dy at low temperatures in short times. • Ideal gas law and in situ temperature and pressure used to assess reaction extent. • It is proposed that reaction rate is proportional to the creation of new surface. - Abstract: Processing of advanced nitride ceramics traditionally requires long durations at high temperatures and, in some cases, in hazardous atmospheres. In this study, dysprosium mononitride (DyN) was rapidly formed from elemental dysprosium in a closed system at ambient temperatures. An experimental procedure was developed to quantify the progress of the nitridation reaction during mechanochemical processing in a high energy planetary ball mill (HEBM) as a function of milling time and intensity using in situ temperature and pressure measurements, SEM, XRD, and particle size analysis. No intermediate phases were formed. It was found that the creation of fresh dysprosium surfaces dictates the rate of the nitridation reaction, which is a function of milling intensity and the number of milling media. These results show clearly that high purity nitrides can be synthesized with short processing times at low temperatures in a closed system requiring a relatively small processing footprint.

  4. High Pressure Soxhlet Type Leachability testing device and leaching test of simulated high-level waste glass at high temperature

    International Nuclear Information System (INIS)

    Senoo, Muneaki; Banba, Tsunetaka; Tashiro, Shingo; Shimooka, Kenji; Araki, Kunio

    1979-11-01

    A High Pressure Soxhlet Type Leachability Testing Device (HIPSOL) was developed to evaluate long-period stability of high-level waste (HLW) solids. For simulated HLW solids, temperature dependency of the leachability was investigated at higher temperatures from 100 0 C to 300 0 C at 80 atm. Leachabilities of cesium and sodium at 295 0 C were 20 and 7 times higher than at 100 0 C, respectively. In the repository, the temperatures around solidified products may be hundred 0 C. It is essential to test them at such elevated temperatures. HIPSOL is also usable for accelerated test to evaluate long-period leaching behavior of HLW products. (author)

  5. In-situ deposition of YBCO high-Tc superconducting thin films by MOCVD and PE-MOCVD

    International Nuclear Information System (INIS)

    Zhao, J.; Noh, D.W.; Chern, C.; Li, Y.Q.; Norris, P.E.; Kear, B.; Gallois, B.

    1991-01-01

    Metal-Organic Chemical Vapor Deposition (MOCVD) offers the advantages of a high degree of compositional control, adaptability for large scale production, and the potential for low temperature fabrication. The capability of operating at high oxygen partial pressure is particularly suitable for in situ formation of high temperature superconducting (HTSC) films. Yttrium barium copper oxide (YBCO) thin films having a sharp zero-resistance transition with T(sub c) greater than 90 K and J(sub c) of approximately 10(exp 4) A on YSZ have been prepared, in situ, at a substrate temperature of about 800 C. Moreover, the ability to form oxide films at low temperature is very desirable for device applications of HTSC materials. Such a process would permit the deposition of high quality HTSC films with a smooth surface on a variety of substrates. Highly c-axis oriented, dense, scratch resistant, superconducting YBCO thin films with mirror-like surfaces have been prepared, in situ, at a reduced substrate temperature as low as 570 C by a remote microwave-plasma enhanced metal-organic chemical vapor deposition (PE-MOCVD) process. Nitrous oxide was used as a reactant gas to generate active oxidizing species. This process, for the first time, allows the formation of YBCO thin films with the orthorhombic superconducting phase in the as-deposited state. The as-deposited films grown by PE-MOCVD show attainment of zero resistance at 72 K with a transition width of about 5 K. MOCVD was carried out in a commercial production scale reactor with the capability of uniform deposition over 100 sq cm per growth run. Preliminary results indicate that PE-MOCVD is a very attractive thin film deposition process for superconducting device technology

  6. Evaluation of heat transfer coefficient of tungsten filaments at low pressures and high temperatures

    International Nuclear Information System (INIS)

    Chondrakis, N.G.; Topalis, F.V.

    2011-01-01

    The paper presents an experimental method for the evaluation of the heat transfer coefficient of tungsten filaments at low pressures and high temperatures. For this purpose an electrode of a T5 fluorescent lamp was tested under low pressures with simultaneous heating in order to simulate the starting conditions in the lamp. It was placed in a sealed vessel in which the pressure was varied from 1 kM (kilo micron) to 760 kM. The voltage applied to the electrode was in the order of the filament's voltage of the lamp at the normal operation with the ballast during the preheating process. The operating frequency ranged from DC to 50 kHz. The experiment targeted on estimating the temperature of the electrode at the end of the first and the ninth second after initiating the heating process. Next, the heat transfer coefficient was calculated at the specific experimental conditions. A mathematical model based on the results was developed that estimates the heat transfer coefficient. The experiments under different pressures confirm that the filament's temperature strongly depends on the pressure.

  7. XPS analysis for cubic boron nitride crystal synthesized under high pressure and high temperature using Li3N as catalysis

    International Nuclear Information System (INIS)

    Guo, Xiaofei; Xu, Bin; Zhang, Wen; Cai, Zhichao; Wen, Zhenxing

    2014-01-01

    Highlights: • The cBN was synthesized by Li 3 N as catalyst under high pressure and high temperature (HPHT). • The film coated on the as-grown cBN crystals was studied by XPS. • The electronic structure variation in the film was investigated. • The growth mechanism of cubic boron nitride crystal was analyzed briefly. - Abstract: Cubic boron nitride (cBN) single crystals are synthesized with lithium nitride (Li3N) as catalyst under high pressure and high temperature. The variation of electronic structures from boron nitride of different layers in coating film on the cBN single crystal has been investigated by X-ray photoelectron spectroscopy. Combining the atomic concentration analysis, it was shown that from the film/cBN crystal interface to the inner, the sp 2 fractions are decreasing, and the sp 3 fractions are increasing in the film at the same time. Moreover, by transmission electron microscopy, a lot of cBN microparticles are found in the interface. For there is no Li 3 N in the film, it is possible that Li 3 N first reacts with hexagonal boron nitride to produce Li 3 BN 2 during cBN crystals synthesis under high pressure and high temperature (HPHT). Boron and nitrogen atoms, required for cBN crystals growth, could come from the direct conversion from hexagonal boron nitride with the catalysis of Li 3 BN 2 under high pressure and high temperature, but not directly from the decomposition of Li 3 BN 2

  8. Principles and application of high pressure-based technologies in the food industry.

    Science.gov (United States)

    Balasubramaniam, V M Bala; Martínez-Monteagudo, Sergio I; Gupta, Rockendra

    2015-01-01

    High pressure processing (HPP) has emerged as a commercially viable food manufacturing tool that satisfies consumers' demand for mildly processed, convenient, fresh-tasting foods with minimal to no preservatives. Pressure treatment, with or without heat, inactivates pathogenic and spoilage bacteria, yeast, mold, viruses, and also spores and extends shelf life. Pressure treatment at ambient or chilled temperatures has minimal impact on product chemistry. The product quality and shelf life are often influenced more by storage conditions and packaging material barrier properties than the treatment itself. Application of pressure reduces the thermal exposure of the food during processing, thereby protecting a variety of bioactive compounds. This review discusses recent scientific advances of high pressure technology for food processing and preservation applications such as pasteurization, sterilization, blanching, freezing, and thawing. We highlight the importance of in situ engineering and thermodynamic properties of food and packaging materials in process design. Current and potential future promising applications of pressure technology are summarized.

  9. Density and Viscosity Measurement of Diesel Fuels at Combined High Pressure and Elevated Temperature

    Directory of Open Access Journals (Sweden)

    Carl Schaschke

    2013-07-01

    Full Text Available We report the measurement of the viscosity and density of various diesel fuels, obtained from British refineries, at elevated pressures up to 500 MPa and temperatures in the range 298 K to 373 K. The measurement and prediction procedures of fluid properties under high pressure conditions is of increasing interest in many processes and systems including enhanced oil recovery, automotive engine fuel injection, braking, and hydraulic systems. Accurate data and understanding of the fluid characteristic in terms of pressure, volume and temperature is required particularly where the fluid is composed of a complex mixture or blend of aliphatic or aromatic hydrocarbons. In this study, high pressure viscosity data was obtained using a thermostatically-controlled falling sinker-type high pressure viscometer to provide reproducible and reliable viscosity data based on terminal velocity sinker fall times. This was supported with density measurements using a micro-pVT device. Both high-pressure devices were additionally capable of illustrating the freezing points of the hydrocarbon mixtures. This work has, thus, provided data that can extend the application of mixtures of commercially available fuels and to test the validity of available predictive density and viscosity models. This included a Tait-style equation for fluid compressibility prediction. For complex diesel fuel compositions, which have many unidentified components, the approach illustrates the need to apply appropriate correlations, which require accurate knowledge or prediction of thermodynamic properties.

  10. Pressure-Drop Considerations in the Characterization of Dew-Point Transfer Standards at High Temperatures

    Science.gov (United States)

    Mitter, H.; Böse, N.; Benyon, R.; Vicente, T.

    2012-09-01

    During calibration of precision optical dew-point hygrometers (DPHs), it is usually necessary to take into account the pressure drop induced by the gas flow between the "point of reference" and the "point of use" (mirror or measuring head of the DPH) either as a correction of the reference dew-point temperature or as part of the uncertainty estimation. At dew-point temperatures in the range of ambient temperature and below, it is sufficient to determine the pressure drop for the required gas flow, and to keep the volumetric flow constant during the measurements. In this case, it is feasible to keep the dry-gas flow into the dew-point generator constant or to measure the flow downstream the DPH at ambient temperature. In normal operation, at least one DPH in addition to the monitoring DPH are used, and this operation has to be applied to each instrument. The situation is different at high dew-point temperatures up to 95 °C, the currently achievable upper limit reported in this paper. With increasing dew-point temperatures, the reference gas contains increasing amounts of water vapour and a constant dry-gas flow will lead to a significant enhanced volume flow at the conditions at the point of use, and therefore, to a significantly varying pressure drop depending on the applied dew-point temperature. At dew-point temperatures above ambient temperature, it is also necessary to heat the reference gas and the mirror head of the DPH sufficiently to avoid condensation which will additionally increase the volume flow and the pressure drop. In this paper, a method is provided to calculate the dry-gas flow rate needed to maintain a known wet-gas flow rate through a chilled mirror for a range of temperature and pressures.

  11. High pressure-temperature electrical conductivity of magnesiowustite as a function of iron oxide concentration

    Science.gov (United States)

    Li, Xiaoyuan; Jeanloz, Raymond

    1990-01-01

    The electrical conductivity of (Mg, Fe)O magnesiowustite containing 9 and 27.5 mol pct FeO has been measured at simultaneously high pressures (30-32 GPa) and temperatures using a diamond anvil cell heated with a continuous wave Nd:YAG laser and an external resistance heater. The conductivity depends strongly on the FeO concentration at both ambient and high pressures. At the pressures and temperatures of about 30 GPa and 2000 K, conditions expected in the lower mantle, the magnesiowustite containing 27.5 percent FeO is 3 orders of magnitude more conductive than that containing 9 percent FeO. The activation energy of magnesiowustite decreases with increasing iron concentration from 0.38 (+ or - 0.09) eV at 9 percent FeO to 0.29 (+ or - 0.05) eV at 27.5 percent FeO.

  12. Cavitation-induced reactions in high-pressure carbon dioxide

    NARCIS (Netherlands)

    Kuijpers, M.W.A.; van Eck, D.; Kemmere, M.F.; Keurentjes, J.T.F.

    2002-01-01

    The feasibility of ultrasound-induced in situ radical formation in liquid carbon dioxide was demonstrated. The required threshold pressure for cavitation could be exceeded at a relatively low acoustic intensity, as the high vapor pressure of CO2 counteracts the hydrostatic pressure. With the use of

  13. Pressure Resistance Welding of High Temperature Metallic Materials

    International Nuclear Information System (INIS)

    Jerred, N.; Zirker, L.; Charit, I.; Cole, J.; Frary, M.; Butt, D.; Meyer, M.; Murty, K.L.

    2010-01-01

    Pressure Resistance Welding (PRW) is a solid state joining process used for various high temperature metallic materials (Oxide dispersion strengthened alloys of MA957, MA754; martensitic alloy HT-9, tungsten etc.) for advanced nuclear reactor applications. A new PRW machine has been installed at the Center for Advanced Energy Studies (CAES) in Idaho Falls for conducting joining research for nuclear applications. The key emphasis has been on understanding processing-microstructure-property relationships. Initial studies have shown that sound joints can be made between dissimilar materials such as MA957 alloy cladding tubes and HT-9 end plugs, and MA754 and HT-9 coupons. Limited burst testing of MA957/HT-9 joints carried out at various pressures up to 400 C has shown encouraging results in that the joint regions do not develop any cracking. Similar joint strength observations have also been made by performing simple bend tests. Detailed microstructural studies using SEM/EBSD tools and fatigue crack growth studies of MA754/HT-9 joints are ongoing.

  14. Miniature Variable Pressure Scanning Electron Microscope for In-Situ Imaging and Chemical Analysis

    Science.gov (United States)

    Gaskin, Jessica A.; Jerman, Gregory; Gregory, Don; Sampson, Allen R.

    2012-01-01

    NASA Marshall Space Flight Center (MSFC) is leading an effort to develop a Miniaturized Variable Pressure Scanning Electron Microscope (MVP-SEM) for in-situ imaging and chemical analysis of uncoated samples. This instrument development will be geared towards operation on Mars and builds on a previous MSFC design of a mini-SEM for the moon (funded through the NASA Planetary Instrument Definition and Development Program). Because Mars has a dramatically different environment than the moon, modifications to the MSFC lunar mini-SEM are necessary. Mainly, the higher atmospheric pressure calls for the use of an electron gun that can operate at High Vacuum, rather than Ultra-High Vacuum. The presence of a CO2-rich atmosphere also allows for the incorporation of a variable pressure system that enables the in-situ analysis of nonconductive geological specimens. Preliminary testing of Mars meteorites in a commercial Environmental SEM(Tradmark) (FEI) confirms the usefulness of lowcurrent/low-accelerating voltage imaging and highlights the advantages of using the Mars atmosphere for environmental imaging. The unique capabilities of the MVP-SEM make it an ideal tool for pursuing key scientific goals of NASA's Flagship Mission Max-C; to perform in-situ science and collect and cache samples in preparation for sample return from Mars.

  15. 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.

  16. Direct In Situ Quantification of HO2 from a Flow Reactor.

    Science.gov (United States)

    Brumfield, Brian; Sun, Wenting; Ju, Yiguang; Wysocki, Gerard

    2013-03-21

    The first direct in situ measurements of hydroperoxyl radical (HO2) at atmospheric pressure from the exit of a laminar flow reactor have been carried out using mid-infrared Faraday rotation spectroscopy. HO2 was generated by oxidation of dimethyl ether, a potential renewable biofuel with a simple molecular structure but rich low-temperature oxidation chemistry. On the basis of the results of nonlinear fitting of the experimental data to a theoretical spectroscopic model, the technique offers an estimated sensitivity of reactor exit temperature range of 398-673 K. Accurate in situ measurement of this species will aid in quantitative modeling of low-temperature and high-pressure combustion kinetics.

  17. Studies on synthesis of diamond at high pressure and temperature

    Science.gov (United States)

    Kailath, Ansu J.

    Diamond is an essential material of modern industry and probably the most versatile abrasive available today. It also has many other industrial applications attributable to its unique mechanical, optical, thermal and electrical properties. Its usage has grown to the extent that there is hardly a production process in modern industry in which industrial diamond does not play a part. Bulk diamond production today is a major industry. Diamonds can be produced in its thermodynamically stable regions either by direct static conversion, or shock-wave conversion. The pressures and temperatures required for direct static conversion are very high. In the catalyst-solvent method, the material used establishes a reaction path with lower activation energy than for direct transformation. This helps in a quicker transformation under more benign conditions. Hence, catalyst-solvent synthesis is readily accomplished and is now a viable and successful industrial process. Diamonds produced by shock wave are very small (approximately 60mu). Therefore this diamond is limited to applications such as polishing compounds only. The quality, quantity, size and morphology of the crystals synthesized by catalyst-solvent process depend on different conditions employed for synthesis. These details, because of commercial reasons are not disclosed in published literature. Hence, systematic studies have been planned to investigate the effect of various growth parameters on the synthesized crystals. During the growth of synthetic diamond crystals, some catalyst-solvent is retained into the crystals in some form and behaves like an impurity. Several physico-mechanical properties of the crystals are found to depend on the total quantity and distribution of these inclusions. Thus, detailed investigation of the crystallization medium and inclusions in synthesized diamonds was also undertaken in the present work. The work incorporated in this thesis has been divided into seven chapters. The first

  18. High-Tc superconductors under very high pressure

    International Nuclear Information System (INIS)

    Wijngaarden, R.J.; Scholtz, J.J.; Eenige, E.N. van; Griessen, R.

    1991-01-01

    High pressure has played a crucial role in the short history of high T c superconductors. Soon after the discovery of superconductivity by Bednorz and Muller in La-Ba-Cu-O, Chu et al. showed that the critical temperature T c could be significantly increased by pressure. This observation led to the discovery of YBa 2 Cu 3 O 7 by Wu et al. with a T c above 90 K. Incidentally, this high T c is probably also due to the fact that YBa 2 Cu 3 O 7 has two CuO 2 layers per unit cell instead of a single one in La-Ba-Cu-O. The authors discuss the high pressure dependence of the oxide superconductors, particularly at pressures above 10 GPa, and the nonmonotonic dependence of transition temperature on pressure

  19. On-line measurements of response time of temperature and pressure sensors in PWRs

    International Nuclear Information System (INIS)

    Hashemian, H.M.

    2004-01-01

    A review of modern techniques for in-situ response time testing of resistance temperature detectors (RTDs), and pressure, level and flow transmitters is presented. These techniques have been developed and validated for use in pressurized and boiling water reactors. The significance of the modern techniques is that they permit testing of installed sensors at process operating conditions and thereby provide the actual in-service response times of the sensors. (author)

  20. Friction and wear studies of nuclear power plant components in pressurized high temperature water environments

    International Nuclear Information System (INIS)

    Ko, P.L.; Zbinden, M.; Taponat, M.C.; Robertson, M.F.

    1997-01-01

    The present paper is part of a series of papers aiming to present the friction and wear results of a collaborative study on nuclear power plant components tested in pressurized high temperature water. The high temperature test facilities and the methodology in presenting the kinetics and wear results are described in detail. The results of the same material combinations obtained from two very different high temperature test facilities (NRCC and EDF) are presented and discussed. (K.A.)

  1. The effect of High Pressure and High Temperature processing on carotenoids and chlorophylls content in some vegetables.

    Science.gov (United States)

    Sánchez, Celia; Baranda, Ana Beatriz; Martínez de Marañón, Iñigo

    2014-11-15

    The effect of High Pressure (HP) and High Pressure High Temperature (HPHT) processing on carotenoid and chlorophyll content of six vegetables was evaluated. In general, carotenoid content was not significantly influenced by HP or HPHT treatments (625 MPa; 5 min; 20, 70 and 117 °C). Regarding chlorophylls, HP treatment caused no degradation or slight increases, while HPHT processes degraded both chlorophylls. Chlorophyll b was more stable than chlorophyll a at 70 °C, but both of them were highly degraded at 117 °C. HPHT treatment at 117 °C provided products with a good retention of carotenoids and colour in the case of red vegetables. Even though the carotenoids also remained in the green vegetables, their chlorophylls and therefore their colour were so affected that milder temperatures need to be applied. As an industrial scale equipment was used, results will be useful for future industrial implementation of this technology. Copyright © 2014 Elsevier Ltd. All rights reserved.

  2. 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.

  3. The Solubility of Tugarinovite (MoO2) in H2O at Elevated Temperatures and Pressures

    Energy Technology Data Exchange (ETDEWEB)

    Saha, Pritam; Anderson, Alan J.; Lee, Thomas; Klemm, Matthias (SFX); (Augsburg)

    2017-12-18

    The solubility of tugarinovite (MoO2) in pure water was investigated at temperatures between 400 and 800°C and at pressures ranging between 95 and 480 MPa by using in situ synchrotron X-ray fluorescence (SXRF) to separately analyze high temperature aqueous solutions in a hydrothermal diamond anvil cell (HDAC). The concentration of molybdenum in the fluid at 400 and 500°C was below detection; however, at temperatures between 600 and 800°C, the solubility of tugarinovite increased with increasing temperature by two orders of magnitude. The molybdenum concentration at 600°C and 800°C is 44 ppm and 658 ppm, respectively. The results complement the data of Kudrin (1985) and provide the first measurement of MoO2solubility at pressure and temperature conditions comparable to intrusion-related Mo deposit formation. The data are also relevant to the study of water chemistry and corrosion product transport in supercritical-water-cooled reactors, where Mo-bearing steel alloys interact with aqueous solutions at temperatures greater than 600°C. The application of in situ SXRF to solubility measurements of sparingly soluble minerals is recommended because it circumvents analytical uncertainties inherent in determinations obtained by quenching and weight loss measurements.

  4. A possible origin of EL6 chondrites from a high temperature-high pressure solar gas

    Energy Technology Data Exchange (ETDEWEB)

    Blander, M. [Argonne National Lab., IL (United States); Unger, L. [Purdue Univ., Westiville, IN (United States). Dept. of Chemistry; Pelton, A.; Eriksson, G. [Ecole Polytechnique, Montreal, PQ (Canada). Dept. of Metallurgy and Materials Engineering

    1994-05-01

    Condensates from a gas of ``solar`` composition were calculated to investigate the origins of EL6 chondrites using a free energy minimization program with a data base for the thermodynamic properties of multicomponent molten silicates as well as for other liquids solids, solid solutions and gaseous species. Because of high volatility of silicon and silica, the high silicon content of metal (2.6 mole %) can only be produced at pressures 10{sup {minus}2} atm at temperatures above 1475 K. At 100--500 atm, a liquid silicate phase crystallizes at a temperature where the silicon content of the metal, ferrosilite content of the enstatite and albite concentration in the plagioclase are close to measured values. In pyrometallurgy, liquid silicates are catalysts for reactions in which Si-O-Si bridging bonds are broken or formed. Thus, one attractive mode for freezing in the compositions of these three phases is disappearance of fluxing liquid. If the plagioclase can continue to react with the nebula without a liquid phase, lower pressures of 10{sup {minus}1} to 1 atm might be possible. Even if the nebula is more reducing than a solar gas, the measured properties of EL6 chondrites might be reconciled with only slightly lower pressures (less than 3X lower). The temperatures would be about the same as indicated in our calculations since the product of the silicon content of the metal and the square of the ferrosilite content of the enstatite constitute a cosmothermometer for the mineral assemblage in EL6 chondrites.

  5. X-ray reflectivity measurements of liquid/solid interfaces under high hydrostatic pressure conditions.

    Science.gov (United States)

    Wirkert, Florian J; Paulus, Michael; Nase, Julia; Möller, Johannes; Kujawski, Simon; Sternemann, Christian; Tolan, Metin

    2014-01-01

    A high-pressure cell for in situ X-ray reflectivity measurements of liquid/solid interfaces at hydrostatic pressures up to 500 MPa (5 kbar), a pressure regime that is particularly important for the study of protein unfolding, is presented. The original set-up of this hydrostatic high-pressure cell is discussed and its unique properties are demonstrated by the investigation of pressure-induced adsorption of the protein lysozyme onto hydrophobic silicon wafers. The presented results emphasize the enormous potential of X-ray reflectivity studies under high hydrostatic pressure conditions for the in situ investigation of adsorption phenomena in biological systems.

  6. Prediction of moisture migration and pore pressure build-up in concrete at high temperatures

    International Nuclear Information System (INIS)

    Ichikawa, Y.; England, G.L.

    2004-01-01

    Prediction of moisture migration and pore pressure build-up in non-uniformly heated concrete is important for safe operation of concrete containment vessels in nuclear power reactors and for assessing the behaviour of fire-exposed concrete structures. (1) Changes in moisture content distribution in a concrete containment vessel during long-term operation should be investigated, since the durability and radiation shielding ability of concrete are strongly influenced by its moisture content. (2) The pressure build-up in a concrete containment vessel in a postulated accident should be evaluated in order to determine whether a venting system is necessary between liner and concrete to relieve the pore pressure. (3) When concrete is subjected to rapid heating during a fire, the concrete can suffer from spalling due to pressure build-up in the concrete pores. This paper presents a mathematical and computational model for predicting changes in temperature, moisture content and pore pressure in concrete at elevated temperatures. A pair of differential equations for one-dimensional heat and moisture transfer in concrete are derived from the conservation of energy and mass, and take into account the temperature-dependent release of gel water and chemically bound water due to dehydration. These equations are numerically solved by the finite difference method. In the numerical analysis, the pressure, density and dynamic viscosity of water in the concrete pores are calculated explicitly from a set of formulated equations. The numerical analysis results are compared with two different sets of experimental data: (a) long-term (531 days) moisture migration test under a steady-state temperature of 200 deg. C, and (b) short-term (114 min) pressure build-up test under transient heating. These experiments were performed to investigate the moisture migration and pressure build-up in the concrete wall of a reactor containment vessel at high temperatures. The former experiment simulated

  7. Thermal conductivity and diffusivity of climax stock quartz monzonite at high pressure and temperature

    International Nuclear Information System (INIS)

    Durham, W.B.; Abey, A.E.

    1981-11-01

    Measurements of thermal conductivity and thermal diffusivity have been made on two samples of Climax Stock quartz monzonite at pressures between 3 and 50 MPa and temperatures between 300 and 523 0 K. Following those measurements the apparatus was calibrated with respect to the thermal conductivity measurement using a reference standard of fused silica. Corrected thermal conductivity of the rock indicates a value at room temperature of 2.60 +- 0.25 W/mK at 3 MPa increasing linearly to 2.75 +- 0.25 W/mK at 50 MPa. These values are unchanged (+- 0.07 W/mK) by heating under 50-MPa pressure to as high as 473 0 K. The conductivity under 50-MPa confining pressure falls smoothly from 2.75 +- 0.25 W/mK at 313 0 K to 2.15 +- 0.25 W/mK at 473 0 K. Thermal diffusivity at 300 0 K was found to be 1.2 +- 0.4 X 10 -6 m 2 /s and shows approximately the same pressure and temperature dependencies as the thermal conductivity

  8. High Temperature and Pressure Alkaline Electrolysis

    DEFF Research Database (Denmark)

    Allebrod, Frank

    against conventional technologies for hydrogen production, such as natural gas reforming, the production and investment costs have to be reduced. A reduction of the investment costs may be achieved by increasing the operational pressure and temperature of the electrolyzer, as this will result in: 1.......3 A cm-2 combined with relatively small production costs may lead to both reduced investment and operating costs for hydrogen and oxygen production. One of the produced electrolysis cells was operated for 350 h. Based on the successful results a patent application covering this novel cell was filed...

  9. Development of a laser-induced plasma probe to measure gas phase plasma signals at high pressures and temperatures

    International Nuclear Information System (INIS)

    Gounder, J.D.; Kutne, P.; Meier, W.

    2012-01-01

    The ability of laser induced breakdown spectroscopy (LIBS) technique for on line simultaneous measurement of elemental concentrations has led to its application in a wide number of processes. The simplicity of the technique allows its application to harsh environments such as present in boilers, furnaces and gasifiers. This paper presents the design of a probe using a custom optic which transforms a round beam into a ring (Donut) beam, which is used for forming a plasma in an atmosphere of nitrogen at high pressure (20 bar) and temperature (200 °C). The LIBS experiments were performed using a high pressure cell to characterize and test the effectiveness of the donut beam transmitted through the LIBS probe and collect plasma signal in back scatter mode. The first tests used the second harmonic of a Nd:YAG laser, pulse width 7 ns, to form a plasma in nitrogen gas at five different pressures (1, 5, 10, 15 and 20 bar) and three different gas temperatures (25, 100 and 200 °C). The uniqueness of this probe is the custom made optic used for reshaping the round laser beam into a ring (Donut) shaped laser beam, which is fed into the probe and focused to form a plasma at the measurement point. The plasma signal is collected and collimated using the laser focusing lens and is reflected from the laser beam axis onto an achromatic lens by a high reflection mirror mounted in the center section of the donut laser beam. The effect of gas pressure and temperature on N(I) lines in the high pressure cell experiment shows that the line intensity decreases with pressure and increases with temperature. Mean plasma temperature was calculated using the ratios of N(I) line intensities ranging from 7400 K to 8900 K at 1 bar and 2400 K to 3200 K at 20 bar for the three different gas temperatures. The results show that as a proof of principle the donut beam optics in combination with the LIBS probe can be used for performing extensive LIBS measurements in well controlled laboratory

  10. Development of a laser-induced plasma probe to measure gas phase plasma signals at high pressures and temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Gounder, J.D., E-mail: James.Gounder@dlr.de; Kutne, P.; Meier, W.

    2012-08-15

    The ability of laser induced breakdown spectroscopy (LIBS) technique for on line simultaneous measurement of elemental concentrations has led to its application in a wide number of processes. The simplicity of the technique allows its application to harsh environments such as present in boilers, furnaces and gasifiers. This paper presents the design of a probe using a custom optic which transforms a round beam into a ring (Donut) beam, which is used for forming a plasma in an atmosphere of nitrogen at high pressure (20 bar) and temperature (200 Degree-Sign C). The LIBS experiments were performed using a high pressure cell to characterize and test the effectiveness of the donut beam transmitted through the LIBS probe and collect plasma signal in back scatter mode. The first tests used the second harmonic of a Nd:YAG laser, pulse width 7 ns, to form a plasma in nitrogen gas at five different pressures (1, 5, 10, 15 and 20 bar) and three different gas temperatures (25, 100 and 200 Degree-Sign C). The uniqueness of this probe is the custom made optic used for reshaping the round laser beam into a ring (Donut) shaped laser beam, which is fed into the probe and focused to form a plasma at the measurement point. The plasma signal is collected and collimated using the laser focusing lens and is reflected from the laser beam axis onto an achromatic lens by a high reflection mirror mounted in the center section of the donut laser beam. The effect of gas pressure and temperature on N(I) lines in the high pressure cell experiment shows that the line intensity decreases with pressure and increases with temperature. Mean plasma temperature was calculated using the ratios of N(I) line intensities ranging from 7400 K to 8900 K at 1 bar and 2400 K to 3200 K at 20 bar for the three different gas temperatures. The results show that as a proof of principle the donut beam optics in combination with the LIBS probe can be used for performing extensive LIBS measurements in well controlled

  11. High Pressure/Temperature Metal Silicate Partitioning of Tungsten

    Science.gov (United States)

    Shofner, G. A.; Danielson, L.; Righter, K.; Campbell, A. J.

    2010-01-01

    The behavior of chemical elements during metal/silicate segregation and their resulting distribution in Earth's mantle and core provide insight into core formation processes. Experimental determination of partition coefficients allows calculations of element distributions that can be compared to accepted values of element abundances in the silicate (mantle) and metallic (core) portions of the Earth. Tungsten (W) is a moderately siderophile element and thus preferentially partitions into metal versus silicate under many planetary conditions. The partitioning behavior has been shown to vary with temperature, silicate composition, oxygen fugacity, and pressure. Most of the previous work on W partitioning has been conducted at 1-bar conditions or at relatively low pressures, i.e. pressure. Predictions based on extrapolation of existing data and parameterizations suggest an increased pressured dependence on metal/ silicate partitioning of W at higher pressures 5. However, the dependence on pressure is not as well constrained as T, fO2, and silicate composition. This poses a problem because proposed equilibration pressures for core formation range from 27 to 50 GPa, falling well outside the experimental range, therefore requiring exptrapolation of a parametereized model. Higher pressure data are needed to improve our understanding of W partitioning at these more extreme conditions.

  12. Solids, liquids, and gases under high pressure

    Science.gov (United States)

    Mao, Ho-Kwang; Chen, Xiao-Jia; Ding, Yang; Li, Bing; Wang, Lin

    2018-01-01

    Pressure has long been recognized as a fundamental thermodynamic variable but its application was previously limited by the available pressure vessels and probes. The development of megabar diamond anvil cells and a battery of associated in-laboratory and synchrotron techniques at the turn of the century have opened a vast new window of opportunities. With the addition of the pressure dimension, we are facing a new world with an order of magnitude more materials to be discovered than all that have been explored at ambient pressure. Pressure drastically and categorically alters all elastic, electronic, magnetic, structural, and chemical properties, and pushes materials across conventional barriers between insulators and superconductors, amorphous and crystalline solids, ionic and covalent compounds, vigorously reactive and inert chemicals, etc. In the process, it reveals surprising high-pressure physics and chemistry and creates novel materials. This review describes the principles and methodology used to reach ultrahigh static pressure: the in situ probes, the physical phenomena to be investigated, the long-pursued goals, the surprising discoveries, and the vast potential opportunities. Exciting examples include the quest for metallic hydrogen, the record-breaking superconducting temperature of 203 K in HnS , the complication of "free-electron gas" alkali metals, the magnetic collapse in 3 d transition elements, the pressure-induced superconductivity from topological insulators, the novel stoichiometry in simple compounds, the interaction of nanoscience, the accomplishment of 750 GPa pressure, etc. These highlights are the integral results of technological achievements, specific measurements, and theoretical advancement; therefore, the same highlights will appear in different sections corresponding to these different aspects. Overall, this review demonstrates that high-pressure research is a new dimension in condensed-matter physics.

  13. Preparation of high-performance ultrafine-grained AISI 304L stainless steel under high temperature and pressure

    Directory of Open Access Journals (Sweden)

    Peng Wang

    2016-08-01

    Full Text Available Bulk ultra-fine grained (UFG AISI 304L stainless steel with excellent mechanical properties was prepared by a high-temperature and high-pressure (HTHP method using nanocrystalline AISI 304L stainless steel powders obtained from ball milling. Samples were sintered in high-pressure conditions using the highest martensite content of AISI 304L stainless steel powders milled for 25 h. Analyses of phase composition and grain size were accomplished by X-ray diffraction and Rietveld refinement. By comparing the reverse martensite transformation under vacuum and HTHP treat, we consider that pressure can effectively promote the change in the process of transformation. Compared with the solid-solution-treated 304L, the hardness and yield strength of the samples sintered under HTHP are considerably higher. This method of preparation of UFG bulk stainless steel may be widely popularised and used to obtain UFG metallic materials with good comprehensive performance.

  14. 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.

  15. Synthesis and high (pressure, temperature) stability of ZnTiO3 polymorphs studied by Raman spectroscopy

    Science.gov (United States)

    Bernert, T.; Ruiz-Fuertes, J.; Bayarjargal, L.; Winkler, B.

    2015-05-01

    The phase-purity of ilmenite-type ZnTiO3 prepared by the ceramic method was investigated in dependence of the conditions during ball milling. The previously proposed addition of 2 ml ethanol to the starting materials led to a significant contamination of the product phase after a subsequent sintering process at 1073 K. However, by omitting ethanol this synthesis route led to a phase-pure sample of ZnTiO3 as confirmed by X-ray powder diffraction and Raman spectroscopy. High-temperature high-pressure experiments gave an ilmenite-type to perovskite-type phase boundary with a slope of dT/dP∼-135 K GPa-1 crossing ambient temperature conditions at ∼ 24 GPa in good agreement with previous calculations. Room-temperature high-pressure Raman spectroscopy experiments have shown the stability of the ilmenite-type phase up to a pressure of at least 38.5 GPa, the highest pressure applied in this study, indicating the presence of a kinetic barrier in this phase transition. The synthesis of ferroelectric LiNbO3-type ZnTiO3 was confirmed by second harmonic generation.

  16. Microbubble-based fiber-optic Fabry-Perot pressure sensor for high-temperature application.

    Science.gov (United States)

    Li, Zhe; Jia, Pinggang; Fang, Guocheng; Liang, Hao; Liang, Ting; Liu, Wenyi; Xiong, Jijun

    2018-03-10

    Using arc discharge technology, we fabricated a fiber-optic Fabry-Perot (FP) pressure sensor with a very low temperature coefficient based on a microbubble that can be applied in a high-temperature environment. The thin-walled microbubble can be fabricated by heating the gas-pressurized hollow silica tube (HST) using a commercial fusion splicer. Then, the well-cut single-mode fiber (SMF) was inserted into the microbubble, and they were fused together. Thus, the FP cavity can be formed between the end of the SMF and the inner surface of the microbubble. The diameter of the microbubble can be up to 360 μm with the thickness of the wall being approximately 0.5 μm. Experimental results show that such a sensor has a linear sensitivity of approximately -6.382  nm/MPa, -5.912  nm/MPa at 20°C, and 600°C within the pressure range of 1 MPa. Due to the thermal expansion coefficient of the SMF being slightly larger than that of silica, we can fuse the SMF and the HST with different lengths; thus, the sensor has a very low temperature coefficient of approximately 0.17 pm/°C.

  17. Novel instrument for high-pressure research at ultra-high temperatures

    International Nuclear Information System (INIS)

    Schiferl, D.; Katz, A.I.; Mills, R.L.

    1985-01-01

    A resistively heated diamond-anvil cell has been used to achieve pressures of 110 kbar at temperatures exceeding 1200 0 C for periods long enough to collect x-ray powder diffraction data with energy-dispersive techniques using ''white'' x-radiation produced at the Stanford Synchrotron Radiation Laboratory. 9 refs., 1 fig

  18. High Efficiency Heat Exchanger for High Temperature and High Pressure Applications

    Energy Technology Data Exchange (ETDEWEB)

    Sienicki, James J. [Argonne National Lab. (ANL), Argonne, IL (United States). Nuclear Engineering Division; Lv, Qiuping [Argonne National Lab. (ANL), Argonne, IL (United States). Nuclear Engineering Division; Moisseytsev, Anton [Argonne National Lab. (ANL), Argonne, IL (United States). Nuclear Engineering Division

    2017-09-29

    CompRex, LLC (CompRex) specializes in the design and manufacture of compact heat exchangers and heat exchange reactors for high temperature and high pressure applications. CompRex’s proprietary compact technology not only increases heat exchange efficiency by at least 25 % but also reduces footprint by at least a factor of ten compared to traditional shell-and-tube solutions of the same capacity and by 15 to 20 % compared to other currently available Printed Circuit Heat Exchanger (PCHE) solutions. As a result, CompRex’s solution is especially suitable for Brayton cycle supercritical carbon dioxide (sCO2) systems given its high efficiency and significantly lower capital and operating expenses. CompRex has already successfully demonstrated its technology and ability to deliver with a pilot-scale compact heat exchanger that was under contract by the Naval Nuclear Laboratory for sCO2 power cycle development. The performance tested unit met or exceeded the thermal and hydraulic specifications with measured heat transfer between 95 to 98 % of maximum heat transfer and temperature and pressure drop values all consistent with the modeled values. CompRex’s vision is to commercialize its compact technology and become the leading provider for compact heat exchangers and heat exchange reactors for various applications including Brayton cycle sCO2 systems. One of the limitations of the sCO2 Brayton power cycle is the design and manufacturing of efficient heat exchangers at extreme operating conditions. Current diffusion-bonded heat exchangers have limitations on the channel size through which the fluid travels, resulting in excessive solid material per heat exchanger volume. CompRex’s design allows for more open area and shorter fluid proximity for increased heat transfer efficiency while sustaining the structural integrity needed for the application. CompRex is developing a novel improvement to its current heat exchanger design where fluids are directed to alternating

  19. In-situ high-pressure measurements and detailed numerical predictions of the catalytic reactivity of methane over platinum

    Energy Technology Data Exchange (ETDEWEB)

    Reinke, M.; Mantzaras, I.; Schaeren, R.; Bombach, R.; Inauen, A.; Schenker, S.

    2003-03-01

    The catalytic reactivity of methane over platinum at pressures of up to 14 bar was evaluated with in-situ Raman measurements and detailed numerical predictions from two different heterogeneous chemical reaction schemes. The best agreement to the measurements was achieved with Deutschmann's reaction scheme that yielded the correct trend for the pressure dependence of the catalytic reactivity, although in absolute terms the reactivity was overpredicted. The catalytic reactivity was consistently underpredicted at all pressures with the reaction scheme of Vlachos. (author)

  20. Vapor pressures and vapor compositions in equilibrium with hypostoichiometric plutonium dioxide at high temperatures

    International Nuclear Information System (INIS)

    Green, D.W.; Fink, J.K.; Leibowitz, L.

    1982-01-01

    Vapor pressures and vapor compositions have been calculated for 1500 less than or equal to T less than or equal to 4000 0 K. Thermodynamic functions for the condensed phase and for each of the gaseous species were combined with an oxygen-potential model extended into the liquid region to obtain the partial pressures of O 2 , O, Pu, PuO and PuO 2 . The calculated oxygen pressures increase very rapidly as stoichiometry is approached. At least part of this increase is a consequence of the exclusion of Pu 6 + from the oxygen-potential model. No reliable method was found to estimate the importance of this ion. As a result of large oxygen potentials at high temperatures, extremely high total pressures that produced unreasonably high vapor densities were calculated. The highest temperature was therefore limited to 400 K, and the range of oxygen-to-metal ratios was limited to 1.994 to 1.70. These calculations show that vapor in equilibrium with hypostoichiometric plutonium dioxide is poorly approximated as PuO 2 for most of the temperture and composition range of interest. The vapor is much more oxygen-rich than the condensed phase. Implications for the (U,Pu)O/sub 2-x/ system are discussed

  1. High-pressure oxidation of methane

    DEFF Research Database (Denmark)

    Hashemi, Hamid; Christensen, Jakob Munkholt; Gersen, Sander

    2016-01-01

    Methane oxidation at high pressures and intermediate temperatures was investigated in a laminar flow reactor and in a rapid compression machine (RCM). The flow-reactor experiments were conducted at 700–900 K and 100 bar for fuel-air equivalence ratios (Φ) ranging from 0.06 to 19.7, all highly...... diluted in nitrogen. It was found that under the investigated conditions, the onset temperature for methane oxidation ranged from 723 K under reducing conditions to 750 K under stoichiometric and oxidizing conditions. The RCM experiments were carried out at pressures of 15–80 bar and temperatures of 800......–1250 K under stoichiometric and fuel-lean (Φ=0.5) conditions. Ignition delays, in the range of 1–100 ms, decreased monotonically with increasing pressure and temperature. A chemical kinetic model for high-pressure methane oxidation was established, with particular emphasis on the peroxide chemistry...

  2. In Situ Studies of Surface Mobility on Noble Metal Model Catalysts Using STM and XPS at Ambient Pressure

    Energy Technology Data Exchange (ETDEWEB)

    Butcher, Derek Robert [Univ. of California, Berkeley, CA (United States)

    2010-06-01

    are present on the Pt(100) hex reconstructed phase, but not the (100)-(1x1) surface. The increase in ethylene pressure caused the adsorbate interactions to dominate the crystal morphology and imposed a surface layer structure that matched the ethylidyne binding geometry. The STM results also showed that the surface was reversibly deformed during imaging due to increases in Pt mobility at high pressure. The size dependence on the activity and surface chemistry of Rh nanoparticles was studied using AP-XPS. The activity was found to increase with particle size. The XPS spectra show that in reaction conditions the particle surface has an oxide layer which is chemically distinct from the surface structure formed by heating in oxygen alone. This surface oxide which is stabilized in the catalytically active CO oxidation conditions was found to be more prevalent on the smaller nanoparticles. The reaction-induced surface segregation behavior of bimetallic noble metal nanoparticles was observed with APXPS. Monodisperse 15 nm RhPd and PdPt nanoparticles were synthesized with well controlled Rh/Pd and Pd/Pt compositions. In-situ XPS studies showed that at 300 C in the presence of an oxidizing environment (100 mTorr NO or O2) the surface concentration of the more easily oxidized element (Rh in RhPd and Pd in PdPt) was increased. Switching the gas environment to more reducing conditions (100 mTorr NO and 100 mTorr CO) caused the surface enrichment of the element with the lowest surface energy in its metallic state. Using in-situ characterization, the redox chemistry and the surface composition of bimetallic nanoparticle samples were monitored in reactive conditions. The particle surfaces were shown to reversibly restructure in response to the gas environment at high temperature. The oxidation behavior of the Pt(110) surface was studied using surface sensitive in-situ characterization by APXPS and STM. In the presence of 500 mTorr O2 and temperatures between 25

  3. High Pressure In Situ X-ray Diffraction Study of MnO to 120 GPa and Comparison with Shock Compression Experiment

    Science.gov (United States)

    Yagi, Takehiko; Kondo, Tadashi; Syono, Yasuhiko

    1997-07-01

    In order to clarify the nature of the phase transformation in MnO observed at around 90 GPa by shock compression experiment (Syono et al., this symposium), high pressure in situ x-ray experiments were carried out up to 120 GPa. Powdered sample was directly compressed in Mao-Bell type diamond anvil and x-ray experiments were carried out using angle dispersive technique by combining synchrotron radiation and imaging plate detector. Distortion of the B1 structured phase into hexagonal unit cell was observed from 25-40 GPa, which continues to increase up to 90 GPa. At around 90 GPa, discontinuous change of the diffraction was observed. This new phase cannot be explained by a simple B2 structure and the analysis of this phase is in progress. This high pressure phase has metallic appearance, which reverses to transparent MnO on release of pressure.

  4. Thermodynamic properties of standard seawater: extensions to high temperatures and pressures

    Directory of Open Access Journals (Sweden)

    J. Safarov

    2009-07-01

    Full Text Available Measurements of (p, ρ, T properties of standard seawater with practical salinity S≈35, temperature T=(273.14 to 468.06 K and pressures, p, up to 140 MPa are reported with the reproducibility of the density measurements observed to be in the average percent deviation range Δρ/ρ=±(0.01 to 0.03%. The measurements are made with a newly constructed vibration-tube densimeter which is calibrated using double-distilled water, methanol and aqueous NaCl solutions. Based on these and previous measurements, an empirical expression for the density of standard seawater has been developed as a function of pressure and temperature. This equation is used to calculate other volumetric properties including isothermal compressibility, isobaric thermal expansibility, differences in isobaric and isochoric heat capacities, the thermal pressure coefficient, internal pressure and the secant bulk modulus. The results can be used to extend the present equation of state of seawater to higher temperatures for pressure up to 140 MPa.

  5. Electrical behavior of Ca, Sr, Ba, and Eu at very high pressures and low temperatures

    International Nuclear Information System (INIS)

    Bundy, F.P.; Dunn, K.J.

    1981-01-01

    Compression of Ca and Sr initially causes an increase in resistivity, probably because of uncrossing of conduction and valence bands. Then at about 180 kbar for Ca and about 35 kbar for Sr the resistivity drops quite abruptly, following which the resistivity again increases with additional pressure, similar to the behavior of Ba starting at room pressure. The high pressure forms of Ba have already been reported to be superconducting, and the experiments confirm this. Superconductivity appears in Sr at about 350 kbar and develops strongly at higher pressures. In the 440 kbar experiment on Ca a resistance drop started at the lower threshold of the temperature capability, 2.1K, suggesting that Ca, too, becomes superconducting at sufficiently high pressures. The high pressure form of Eu above 125 kbar was tested for superconductivity down to 2.2K with negative results. (Auth.)

  6. Anomalous phase transition of InN nanowires under high pressure

    International Nuclear Information System (INIS)

    Tang Shun-Xi; Zhu Hong-Yang; Jiang Jun-Ru; Wu Xiao-Xin; Dong Yun-Xuan; Zhang Jian; Cui Qi-Liang; Yang Da-Peng

    2015-01-01

    Uniform InN nanowires were studied under pressures up to 35.5 GPa by using in situ synchrotron radiation x-ray diffraction technique at room temperature. An anomalous phase transition behavior has been discovered. Contrary to the results in the literature, which indicated that InN undergoes a fully reversible phase transition from the wurtzite structure to the rocksalt type structure, the InN nanowires in this study unusually showed a partially irreversible phase transition. The released sample contained the metastable rocksalt phase as well as the starting wurtzite one. The experimental findings of this study also reveal the potentiality of high pressure techniques to synthesize InN nanomaterials with the metastable rocksalt type structure, in addition to the generally obtained zincblende type one. (paper)

  7. The refrigeration of high temperature superconductors between 25K and 65K

    International Nuclear Information System (INIS)

    Richardson, R.N.; Scurlock, R.G.; Tavner, A.C.R.

    1996-01-01

    The present state of the art indicates that acceptable j - H characteristics for power applications of the new high Tc superconductors will only be achieved using materials at temperatures below liquid nitrogen temperature. A boiling point of 27.1K and high specific cooling capacity make neon an eminently suitable choice of refrigerant at these temperatures. A cryostat has been constructed which employs a two stage Gifford-McMahon cooler to liquefy neon gas. The cryostat contains up to 5 litres of liquid neon which can be used for open-quote in-situ close-quote experiments or transfer to another cryostat. Another set of cryostats are being used with liquid nitrogen/oxygen mixtures at reduced pressure for temperatures down to 50K. All these cryostats provide a core facility for characterising and operating high T c superconductors at Southampton

  8. 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.

  9. Viscosity of liquid sulfur under high pressure

    International Nuclear Information System (INIS)

    Terasaki, Hidenori; Kato, T; Funakoshi, K; Suzuki, A; Urakawa, S

    2004-01-01

    The viscosity of liquid sulfur up to 9.7 GPa and 1067 K was measured using the in situ x-ray radiography falling sphere method. The viscosity coefficients were found to range from 0.11 to 0.69 Pa s, and decreased continuously with increasing pressure under approximately constant homologous temperature conditions. The observed viscosity variation suggests that a gradual structural change occurs in liquid sulfur with pressure up to 10 GPa. The L-L' transition in liquid sulfur proposed by Brazhkin et al (1991 Phys. Lett. A 154 413) from thermobaric measurements has not been confirmed by the present viscometry

  10. Interfacial tension measurement between CO2 and brines under high temperature and elevated pressure conditions

    Science.gov (United States)

    Li, X.; Boek, E. S.; Maitland, G. C.; Trusler, J. P. M.

    2012-04-01

    We have investigated the dependence of interfacial tension of (CO2 + brine) on temperature, pressure and salinity (including both salt type and molality) over the range of conditions applicable to CO2 storage in saline aquifers. The study covered a wide range of measurements of the interfacial tensions between carbon dioxide and (NaCl + KCl)(aq), CaCl2(aq), MgCl2(aq), Na2SO4(aq), KHCO3(aq), NaHCO3(aq) and two laboratory constructed brines with molality ranging from (0.3 to 5.0) mol·kg-1. The measurements were made at temperatures between (298 and 448) K at various pressures up to 50 MPa, using the pendant drop method in a high-pressure view cell filled with water-saturated CO2. The drop to be imaged was created by injecting brine from a high-pressure syringe pump into a capillary sealed through the top of the cell. The expanded uncertainties of the experimental state variables at 95 % confidence are +0.05 K in temperature and +70 kPa in pressure. For the interfacial tension, the overall expanded relative uncertainty at 95 % confidence was +1.6%. The experimental results show that interfacial tension for all the systems increases linearly with molality, indicating that relatively few measurements and simple interpolation procedures are adequate for describing this property accurately over wide ranges of conditions.

  11. Temperature measurement in the liquid helium range at pressure

    International Nuclear Information System (INIS)

    Itskevich, E.S.; Krajdenov, V.F.

    1978-01-01

    The use of bronze and germanium resistance thermometers and the use of a (Au + 0.07 % Fe)-Cu thermocouple for temperature measurements from 1.5 to 4.2 K in the hydrostatic compression of up to 10 kbar are considered. To this aim, the thermometer resistance as a function of temperature and pressure is measured. It is revealed that pressure does not change the thermometric response of the bronze resistance thermometer but only shifts it to the region of lower temperatures. The identical investigations of the germanium resistance thermometer shows that strong temperature dependence and the shift of its thermometric response under the influence of pressure make the use of germanium resistance thermometers in high-pressure chambers very inconvenient. The results of the analysis of the (Au + 0.07 % Fe) - Cu thermocouple shows that with a 2 per cent accuracy the thermocouple Seebeck coefficient does not depend on pressure. It permits to use this thermocouple for temperature measurements at high pressures

  12. First-principles study of optical, elastic anisotropic and thermodynamic properties of TiN under high temperature and high pressure

    Directory of Open Access Journals (Sweden)

    R. Yang

    2017-12-01

    Full Text Available The optical, elastic anisotropic and thermodynamic properties of TiN in the NaCl (B1 structure are analyzed in detail in the temperature range from 0 to 2000 K and the pressure range from 0 to 20 GPa. From the calculated dielectric constants, a first order isostructural phase transition between 29 and 30 GPa is found for TiN. The absorption spectra exhibit high values ranging from the far infrared region to the ultra-violet one. The anisotropy value of Young's modulus of TiN is smaller than that of c-BN at 0 GPa and the anisotropy of TiN clearly increases with an increase of pressure. The effects of pressure and temperature on the bulk modulus, Grüneisen parameter, Gibbs free energy, and Debye temperature are significant. The Grüneisen parameter of TiN is much larger than that of c-BN. At temperatures below 1000 K, TiN's heat capacity is much larger than that of c-BN.

  13. A Passive Pressure Sensor Fabricated by Post-Fire Metallization on Zirconia Ceramic for High-Temperature Applications

    Directory of Open Access Journals (Sweden)

    Tao Luo

    2014-09-01

    Full Text Available A high-temperature pressure sensor realized by the post-fire metallization on zirconia ceramic is presented. The pressure signal can be read out wirelessly through the magnetic coupling between the reader antenna and the sensor due to that the sensor is equivalent to an inductive-capacitive (LC resonance circuit which has a pressure-sensitive resonance frequency. Considering the excellent mechanical properties in high-temperature environment, multilayered zirconia ceramic tapes were used to fabricate the pressure-sensitive structure. Owing to its low resistivity, sliver paste was chosen to form the electrical circuit via post-fire metallization, thereby enhancing the quality factor compared to sensors fabricated by cofiring with a high-melting-point metal such as platinum, tungsten or manganese. The design, fabrication, and experiments are demonstrated and discussed in detail. Experimental results showed that the sensor can operate at 600 °C with quite good coupling. Furthermore, the average sensitivity is as high as 790 kHz/bar within the measurement range between 0 and 1 Bar.

  14. Time-resolved x-ray diffraction measurement of C60 under high pressure and temperature using synchrotron radiation

    International Nuclear Information System (INIS)

    Horikawa, T; Suito, K; Kobayashi, M; Onodera, A

    2002-01-01

    C 60 has been studied by means of time-resolved x-ray diffraction measurements using synchrotron radiation. Diffraction patterns were recorded at intervals of 1-10 min for samples under high pressure (12.5 and 14.3 GPa) and high temperature (up to 800 deg. C) for, at the longest, 3 h. Time, pressure, and temperature dependences of the C 60 structure are presented and the relevance to the hardness of materials derived from C 60 is discussed

  15. In situ observation techniques of protective oxide layer

    International Nuclear Information System (INIS)

    Doi, Takashi; Adachi, Takeharu; Usuki, Noriaki

    2015-01-01

    In situ analyzing techniques for investigating a surface and interface change during corrosion and oxidation of metals by using Raman scattering spectroscopy (Raman), X-ray diffraction (XRD) and X-ray photoemission spectroscopy (XPS) are present. The Raman spectra revealed that a crystal structure and distribution of corrosion products varied during corrosion progress at elevated temperature and high pressure electrolyte. Time dependent XRD measurements made clear the behavior of the electrochemical reduction of a rust and the iso thermal transformation of a scale on a steel. It was demonstrated that XPS was capable of the in-situ measurements for initial stage of high temperature oxidation. (author)

  16. In situ analysis of proteins at high temperatures mediated by capillary-flow hydrothermal UV-vis spectrophotometer with a water-soluble chromogenic reagent.

    Science.gov (United States)

    Kawamura, Kunio; Nagayoshi, Hiroki; Yao, Toshio

    2010-05-14

    In situ monitoring of quantities, interactions, and conformations of proteins is essential for the study of biochemistry under hydrothermal environments and the analysis of hyperthermophilic organisms in natural hydrothermal systems on Earth. We have investigated the potential of a capillary-flow hydrothermal UV-vis spectrophotometer (CHUS) for performing in situ measurements of proteins and determining their behavior at extremely high temperatures, in combination with a chromogenic reagents probe, which interacts with the proteins. The spectral shift obtained using a combination of water-soluble porphyrin (TPPS) and bovine serum albumin (BSA) was the best among the spectral shifts obtained using different combinations of chromogenic reagents and proteins. The association behavior of TPPS with BSA was investigated in detail using CHUS at temperatures up to 175 degrees C and the association constant (K(ass)) of TPPS with BSA was successfully determined at temperatures up to 100 degrees C. The lnK(ass) values were inversely proportional to the T(-1) values in the temperature range 50-100 degrees C. These analyses showed for the first time that the decrease of association of TPPS with BSA is due to the conformational change, fragmentation, and/or denaturing of BSA rather than the decrease of the hydrophobic association between TPPS and BSA. This study conclusively demonstrates the usability of the CHUS system with a chromogenic reagent as an in situ detection and measurement system for thermostable proteins at extremely high temperatures. Copyright 2010 Elsevier B.V. All rights reserved.

  17. Research design and improvement of high temperature high pressure solenoid valve

    International Nuclear Information System (INIS)

    Luo Yongtang

    1987-12-01

    A process for development of the pilot type high temperature high pressure solenoid valve used in a PWR power plant is described. The whole development process might be divided into two phases: research design and improvement. In the former phase the questions had chiefly been approached in the following several aspects: the principle construction design, the determination of values for the constructionally key elements, the valve seal design and the solenoid actuator design, and made such valve's successful design in the main. In the latter phase an improvement had been made upon such valve against the problems during the testing use of the valve for a period of time, i.e. the unsatisfactory leak tightness, and achieved satisfactory results. The consummate success in this development not only has met the needs of the engineering project, but also made us obtain a valuable experience useful to design the similar valves

  18. High-pressure and high-temperature physical properties of half-metallic full-Heusler alloy Mn{sub 2}RuSi by first-principles and quasi-harmonic Debye model

    Energy Technology Data Exchange (ETDEWEB)

    Song, Ting [State Key Laboratory of Advanced Processing and Recycling of Non-ferrous Metals, Lanzhou University of Technology, Lanzhou 730050 (China); School of Mathematics and Physics, Lanzhou Jiaotong University, Lanzhou 730070 (China); Ma, Qin, E-mail: maqin_lut@yeah.net [State Key Laboratory of Advanced Processing and Recycling of Non-ferrous Metals, Lanzhou University of Technology, Lanzhou 730050 (China); Sun, Xiao-Wei [School of Mathematics and Physics, Lanzhou Jiaotong University, Lanzhou 730070 (China); Liu, Zi-Jiang [School of Mathematics and Physics, Lanzhou Jiaotong University, Lanzhou 730070 (China); Department of Physics, Lanzhou City University, Lanzhou 730070 (China); Wei, Xiao-Ping [School of Mathematics and Physics, Lanzhou Jiaotong University, Lanzhou 730070 (China); Tian, Jun-Hong [School of Mathematics and Physics, Lanzhou Jiaotong University, Lanzhou 730070 (China); Institute of Atomic and Molecular Physics, Sichuan University, Chengdu 610065 (China)

    2017-02-15

    First-principles calculations based on density functional theory and quasi-harmonic Debye model are used to investigate the high-pressure and high-temperature physical properties, including the lattice constant, magnetic moment, density of states, pressure-volume-temperature relationship, bulk modulus, thermal expansivity, heat capacity, and Grüneisen parameter for the new Mn-based full-Heusler alloy Mn{sub 2}RuSi in CuHg{sub 2}Ti-type structure. The optimized equilibrium lattice constant is consistent with experimental and other theoretical results. The calculated total spin magnetic moment remains an integral value of 2.0 μ{sub B} in the lattice constant range of 5.454–5.758 Å, and then decreases very slowly with the decrease of lattice constant to 5.333 Å. By the spin resolved density of states calculations, we have shown that Mn{sub 2}RuSi compound presents half-metallic ferrimagnetic properties under the equilibrium lattice constant. The effects of temperature and pressure on bulk modulus, thermal expansivity, heat capacity, and Grüneisen parameter are opposite, which are consistent with a compression rate of volume. Furthermore, the results show that the effect of temperature is larger than pressure for heat capacity and the effect of high temperature and pressure on thermal expansion coefficient is small. All the properties of Mn{sub 2}RuSi alloy are summarized in the pressure range of 0–100 GPa and the temperature up to 1200 K. - Highlights: • High-pressure and high-temperature physical properties of Mn2RuSi were investigated. • Ferrimagnetic ground state has been confirmed in Mn2RuSi alloy. • The first-principle calculations and quasi-harmonic Debye model were used. • The pressure up to 100 GPa and the temperature up to 1200 K.

  19. An Integrative Genomic Island Affects the Adaptations of Piezophilic Hyperthermophilic Archaeon Pyrococcus yayanosii to High Temperature and High Hydrostatic Pressure

    Directory of Open Access Journals (Sweden)

    Zhen Li

    2016-11-01

    Full Text Available Deep-sea hydrothermal vent environments are characterized by high hydrostatic pressure and sharp temperature and chemical gradients. Horizontal gene transfer is thought to play an important role in the microbial adaptation to such an extreme environment. In this study, a 21.4-kb DNA fragment was identified as a genomic island, designated PYG1, in the genomic sequence of the piezophilic hyperthermophile Pyrococcus yayanosii. According to the sequence alignment and functional annotation, the genes in PYG1 could tentatively be divided into five modules, with functions related to mobility, DNA repair, metabolic processes and the toxin-antitoxin system. Integrase can mediate the site-specific integration and excision of PYG1 in the chromosome of P. yayanosii A1. Gene replacement of PYG1 with a SimR cassette was successful. The growth of the mutant strain ∆PYG1 was compared with its parent strain P. yayanosii A2 under various stress conditions, including different pH, salinity, temperature and hydrostatic pressure. The ∆PYG1 mutant strain showed reduced growth when grown at 100 °C, while the biomass of ∆PYG1 increased significantly when cultured at 80 MPa. Differential expression of the genes in module Ⅲ of PYG1 was observed under different temperature and pressure conditions. This study demonstrates the first example of an archaeal integrative genomic island that could affect the adaptation of the hyperthermophilic piezophile P. yayanosii to high temperature and high hydrostatic pressure.

  20. A film bulk acoustic resonator-based high-performance pressure sensor integrated with temperature control system

    International Nuclear Information System (INIS)

    Zhang, Mengying; Zhao, Zhan; Du, Lidong; Fang, Zhen

    2017-01-01

    This paper presented a high-performance pressure sensor based on a film bulk acoustic resonator (FBAR). The support film of the FBAR chip was made of silicon nitride and the part under the resonator area was etched to enhance the sensitivity and improve the linearity of the pressure sensor. A micro resistor temperature sensor and a micro resistor heater were integrated in the chip to monitor and control the operating temperature. The sensor chip was fabricated, and packaged in an oscillator circuit for differential pressure detection. When the detected pressure ranged from  −100 hPa to 600 hPa, the sensitivity of the improved FBAR pressure sensor was  −0.967 kHz hPa −1 , namely  −0.69 ppm hPa −1 , which was 19% higher than that of existing sensors with a complete support film. The nonlinearity of the improved sensor was less than  ±0.35%, while that of the existing sensor was  ±5%. To eliminate measurement errors from humidity, the temperature control system integrated in the sensor chip controlled the temperature of the resonator up to 75 °C, with accuracy of  ±0.015 °C and power of 20 mW. (paper)

  1. Nanoparticle Metamorphosis: An in Situ High-Temperature Transmission Electron Microscopy Study of the Structural Evolution of Heterogeneous Au:Fe 2 O 3 Nanoparticles

    KAUST Repository

    Baumgardner, William J.

    2014-05-27

    High-temperature in situ electron microscopy and X-ray diffraction have revealed that Au and Fe2O3 particles fuse in a fluid fashion at temperatures far below their size-reduced melting points. With increasing temperature, the fused particles undergo a sequence of complex structural transformations from surface alloy to phase segregated and ultimately core-shell structures. The combination of in situ electron microscopy and spectroscopy provides insights into fundamental thermodynamic and kinetic aspects governing the formation of heterogeneous nanostructures. The observed structural transformations present an interesting analogy to thin film growth on the curved surface of a nanoparticle. Using single-particle observations, we constructed a phase diagram illustrating the complex relationships among composition, morphology, temperature, and particle size. © 2014 American Chemical Society.

  2. Nanoparticle Metamorphosis: An in Situ High-Temperature Transmission Electron Microscopy Study of the Structural Evolution of Heterogeneous Au:Fe 2 O 3 Nanoparticles

    KAUST Repository

    Baumgardner, William J.; Yu, Yingchao; Hovden, Robert; Honrao, Shreyas; Hennig, Richard G.; Abruñ a, Hé ctor D.; Muller, David; Hanrath, Tobias

    2014-01-01

    High-temperature in situ electron microscopy and X-ray diffraction have revealed that Au and Fe2O3 particles fuse in a fluid fashion at temperatures far below their size-reduced melting points. With increasing temperature, the fused particles undergo a sequence of complex structural transformations from surface alloy to phase segregated and ultimately core-shell structures. The combination of in situ electron microscopy and spectroscopy provides insights into fundamental thermodynamic and kinetic aspects governing the formation of heterogeneous nanostructures. The observed structural transformations present an interesting analogy to thin film growth on the curved surface of a nanoparticle. Using single-particle observations, we constructed a phase diagram illustrating the complex relationships among composition, morphology, temperature, and particle size. © 2014 American Chemical Society.

  3. High-pressure oxidation of ethane

    DEFF Research Database (Denmark)

    Hashemi, Hamid; G. Jacobsen, Jon; Rasmussen, Christian T.

    2017-01-01

    Ethane oxidation at intermediate temperatures and high pressures has been investigated in both a laminar flow reactor and a rapid compression machine (RCM). The flow-reactor measurements at 600–900 K and 20–100 bar showed an onset temperature for oxidation of ethane between 700 and 825 K, depending...... on pressure, stoichiometry, and residence time. Measured ignition delay times in the RCM at pressures of 10–80 bar and temperatures of 900–1025 K decreased with increasing pressure and/or temperature. A detailed chemical kinetic model was developed with particular attention to the peroxide chemistry. Rate...

  4. 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.

  5. High Temperature, high pressure equation of state density correlations and viscosity correlations

    Energy Technology Data Exchange (ETDEWEB)

    Tapriyal, D.; Enick, R.; McHugh, M.; Gamwo, I.; Morreale, B.

    2012-07-31

    Global increase in oil demand and depleting reserves has derived a need to find new oil resources. To find these untapped reservoirs, oil companies are exploring various remote and harsh locations such as deep waters in Gulf of Mexico, remote arctic regions, unexplored deep deserts, etc. Further, the depth of new oil/gas wells being drilled has increased considerably to tap these new resources. With the increase in the well depth, the bottomhole temperature and pressure are also increasing to extreme values (i.e. up to 500 F and 35,000 psi). The density and viscosity of natural gas and crude oil at reservoir conditions are critical fundamental properties required for accurate assessment of the amount of recoverable petroleum within a reservoir and the modeling of the flow of these fluids within the porous media. These properties are also used to design appropriate drilling and production equipment such as blow out preventers, risers, etc. With the present state of art, there is no accurate database for these fluid properties at extreme conditions. As we have begun to expand this experimental database it has become apparent that there are neither equations of state for density or transport models for viscosity that can be used to predict these fundamental properties of multi-component hydrocarbon mixtures over a wide range of temperature and pressure. Presently, oil companies are using correlations based on lower temperature and pressure databases that exhibit an unsatisfactory predictive capability at extreme conditions (e.g. as great as {+-} 50%). From the perspective of these oil companies that are committed to safely producing these resources, accurately predicting flow rates, and assuring the integrity of the flow, the absence of an extensive experimental database at extreme conditions and models capable of predicting these properties over an extremely wide range of temperature and pressure (including extreme conditions) makes their task even more daunting.

  6. High Temperature and Pressure Alkaline Electrochemical Reactor for Conversion of Power to Chemicals

    DEFF Research Database (Denmark)

    Chatzichristodoulou, Christodoulos

    2016-01-01

    forces. Raising the operating temperature offers a means to boost performance, as both ionic transport and reaction kinetics are exponentially activated with temperature. Indeed, we have demonstrated alkaline electrolysis cells operating at 200-250 °C and 20-50 bar at very high efficiencies and power...... been established enabling experiments with gaseous or liquids reactants/products at cell sizes of up to 25 cm2. Efforts are currently directed towards the investigation of the intrinsic activity of mixed oxides for the oxygen evolution reaction at elevated temperatures and pressures...

  7. Behavior of pressure rise and condensation caused by water evaporation under vacuum at high temperature

    International Nuclear Information System (INIS)

    Takase, Kazuyuki; Kunugi, Tomoaki; Yamazaki, Seiichiro; Fujii, Sadao

    1998-01-01

    Pressure rise and condensation characteristics during the ingress-of-coolant event (ICE) in fusion reactors were investigated using the preliminary ICE apparatus with a vacuum vessel (VV), an additional tank (AT) and an isolation valve (IV). A surface of the AT was cooled by water at RT. The high temperature and pressure water was injected into the VV which was heated up to 250degC and pressure and temperature transients in the VV were measured. The pressure increased rapidly with an injection time of the water because of the water evaporation. After the IV was opened and the VV was connected with the AT, the pressure in the VV decreased suddenly. From a series of the experiments, it was confirmed that control factors on the pressure rise were the flushing evaporation and boiling heat transfer in the VV, and then, condensation of the vapor after was effective to the depressurization in the VV. (author)

  8. Thermal conductivity and diffusivity of climax stock quartz monzonite at high pressure and temperature

    Energy Technology Data Exchange (ETDEWEB)

    Durham, W.B.; Abey, A.E.

    1981-11-01

    Measurements of thermal conductivity and thermal diffusivity have been made on two samples of Climax Stock quartz monzonite at pressures between 3 and 50 MPa and temperatures between 300 and 523{sup 0}K. Following those measurements the apparatus was calibrated with respect to the thermal conductivity measurement using a reference standard of fused silica. Corrected thermal conductivity of the rock indicates a value at room temperature of 2.60 +- 0.25 W/mK at 3 MPa increasing linearly to 2.75 +- 0.25 W/mK at 50 MPa. These values are unchanged (+- 0.07 W/mK) by heating under 50-MPa pressure to as high as 473{sup 0}K. The conductivity under 50-MPa confining pressure falls smoothly from 2.75 +- 0.25 W/mK at 313{sup 0}K to 2.15 +- 0.25 W/mK at 473{sup 0}K. Thermal diffusivity at 300{sup 0}K was found to be 1.2 +- 0.4 X 10{sup -6} m{sup 2}/s and shows approximately the same pressure and temperature dependencies as the thermal conductivity.

  9. Pressure/temperature fluid cell apparatus for the neutron powder diffractometer instrument: Probing atomic structure in situ

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Hsiu-Wen; Fanelli, Victor R.; Reiche, Helmut M.; Larson, Eric; Taylor, Mark A.; Siewenie, Joan [Lujan Neutron Scattering Center, Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States); Xu, Hongwu [Earth and Environmental Sciences Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States); Zhu, Jinlong [High Pressure Science and Engineering Center, Department of Physics and Astronomy, The University of Nevada, Las Vegas, Nevada 89154, USA and National Lab for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190 (China); Page, Katharine, E-mail: pagekl@ornl.gov [Spallation Neutron Source, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831 (United States)

    2014-12-15

    This contribution describes a new local structure compatible gas/liquid cell apparatus for probing disordered materials at high pressures and variable temperatures in the Neutron Powder Diffraction instrument at the Lujan Neutron Scattering Center, Los Alamos National Laboratory. The new sample environment offers choices for sample canister thickness and canister material type. Finite element modeling is utilized to establish maximum allowable working pressures of 414 MPa at 15 K and 121 MPa at 600 K. High quality atomic pair distribution function data extraction and modeling have been demonstrated for a calibration standard (Si powder) and for supercritical and subcritical CO{sub 2} measurements. The new sample environment was designed to specifically target experimental studies of the local atomic structures involved in geologic CO{sub 2} sequestration, but will be equally applicable to a wide variety of energy applications, including sorption of fluids on nano/meso-porous solids, clathrate hydrate formation, catalysis, carbon capture, and H{sub 2} and natural gas uptake/storage.

  10. 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.

  11. 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.

  12. Quantitative Raman Spectroscopy to monitor microbial metabolism in situ under pressure

    Science.gov (United States)

    Picard, A.; Daniel, I.; Oger, P.

    2006-12-01

    Although high hydrostatic pressure (HHP) biotopes are ubiquitous on Earth, little is known about the metabolism of piezophile organisms. Cell culture under HHP can be technically challenging, and equipment- dependent. In addition, the depressurization step required for analysis can lead to erroneous data. Therefore, to understand how piezophile organisms react to pressure, it is crucial to be able to monitor their activity in situ under HHP. We developed the use of Quantitative Raman Spectroscopy (QRS, 1) to monitor in situ the metabolism of organic molecules. This technique is based on the specific spectral signature of an analyte from which its concentration can be deduced. An application of this technique to the monitoring of alcoholic fermentation by the piezotolerant micro-eucaryote Saccharomyces cerevisiae is presented. Ethanol fermentation from glucose was monitored during 24h from ambient P up to 100 MPa in the low- pressure Diamond Anvil Cell (lpDAC, 2). The experimental compression chamber consisted in a 300 μm-thick Ni gasket in which a 500 μm-diameter hole was drilled. Early-stationnary yeast cells were inoculated into fresh low-fluorescence medium containing 0.15 M of glucose. Ethanol concentration was determined in situ by QRS using the symmetric C-C stretching mode of ethanol at 878 cm-1 normalizing the data to the intensity of the sulfate S-O stretching mode at 980 cm-1. In our setup, the detection limit of ethanol is lower than 0.05 mM with a precision below 1%. At ambient P, ethanol production in the lpDAC and in control experiments proceeds with the same kinetics. Thus, yeast is not affected by its confinement. This is further confirmed by its ability to bud with a generation time similar to control experiments performed in glass tubes at ambient pressure inside the lpDAC. Ethanol production by yeast occurs to at least 65 MPa (3). At 10 MPa, fermentation proceeds 3 times faster than at ambient P. Fermentation rates decrease linearly from 20 to

  13. 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.

  14. Hydrogen termination of CVD diamond films by high-temperature annealing at atmospheric pressure

    NARCIS (Netherlands)

    Seshan, V.; Ullien, D.; Castellanos-Gomez, A.; Sachdeva, S.; Murthy, D.H.K.; Savenije, T.J.; Ahmad, H.A.; Nunney, T.S.; Janssens, S.D.; Haenen, K.; Nesládek, M.; Van der Zant, H.S.J.; Sudhölter, E.J.R.; De Smet, L.C.P.M.

    2013-01-01

    A high-temperature procedure to hydrogenate diamond films using molecular hydrogen at atmospheric pressure was explored. Undoped and doped chemical vapour deposited (CVD) polycrystalline diamond films were treated according to our annealing method using a H2 gas flow down to ?50 ml/min (STP) at

  15. Apparatus development for high-pressure X-ray diffraction using synchrotron radiation

    International Nuclear Information System (INIS)

    Martinez, L.G.; Orlando, M.T.D.; Rossi, J.L.; Passamai Junior, J.L.; Melo, F.C.L.; Ferreira, F.F.

    2006-01-01

    Some phenomena in the field of condensed matter physics can be studied when the matter is submitted to extreme conditions of pressure, magnetic fields or temperatures. Once submitted to these conditions it is generally necessary to measure the properties of the matter in situ. The existence of a synchrotron light laboratory in Brazil opens up the chance of studying materials in extreme conditions by techniques like X-ray diffraction and absorption. However, when compared to high-energy synchrotrons accelerators, the Brazilian source offers a narrower energy range and lower flux. These facts impose limitation to perform diffraction experiments by energy dispersion and, consequently, the use of pressure cells with denser anvils like diamond. However, for a lower-pressure range, preliminary studies showed the viability of measurements in an angular dispersion configuration. This allows the use of silicon carbide anvils B 4C . In this work it is described the development of a hydrostatic pressure cell suitable for X-rays diffraction measurements in the Brazilian Synchrotron Light Laboratory using materials and technologies developed by the institutions and researchers involved in this project (IPEN, UFES, CTA and LNLS). This development can provide the scientific community with the possibility of performing X-ray diffraction measurements under hydrostatic pressure, initially up to 2 GPa, with possibilities of increasing the maximum pressure to higher values, with or without application of magnetic fields and high or low temperatures. (author)

  16. X-ray diffraction at high pressure and high/low temperatures using synchrotron radiation. Applications in the study of spinel structures

    International Nuclear Information System (INIS)

    Gerward, L.; Jiang, J.Z.; Olsen, J.S.; Recio, J.M.; Wakowska, A.

    2004-01-01

    High-pressure x-ray diffraction made a quantum leap in the 1960's with the advent of the diamond-anvil cell. This ingenious device, where two opposing diamond faces apply pressure to a tiny sample, made it possible to replicate the pressure near the core of the Earth by turning a thumbscrew. Multianvil cells, such as the Japanese MAX80 press, were developed for combined high-pressure and high-temperature studies. The availability n at about the same time n of dedicated synchrotron radiation sources of hard x-rays was another big step forward. Since then, the white-beam energy-dispersive method has been the workhorse for high pressure, high-temperature x-ray diffraction, although it is now gradually being replaced by high-resolution monochromatic methods based on the image plate, the CCD camera or other electronic area detectors. The first part of the paper is a review of high-pressure x-ray diffraction (HPXRD), covering roughly the last three decades. Physical parameters, such as the bulk modulus, the compressibility and the equation of state, are defined. The diamond-anvil cell, the multianvil press and other high-pressure devices are described, as well as synchrotron radiation sources and recording techniques. Examples are drawn from current experimental and theoretical research on crystal structures of the spinel type. Accurate structural parameters have been determined at ambient conditions and at low temperatures using single-crystal diffraction and four-circle diffractometers. The uniform high-pressure behavior of the oxide spinels has been investigated in detail and compared with the corresponding behavior of selenium-based spinels. The synthesis of advanced novel materials is exemplified in the case of the cubic spinel Si 3 N 4 . This and other nitrogen spinels, which have a bulk modulus of about 300 GPa modulated by the actual cation, are opening a road towards superhard materials. The paper finishes off with an outlook into the future, where new

  17. 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.

  18. Spin Crossover and the Magnetic P- T Phase Diagram of Hematite at High Hydrostatic Pressures and Cryogenic Temperatures

    Science.gov (United States)

    Gavriliuk, A. G.; Struzhkin, V. V.; Mironovich, A. A.; Lyubutin, I. S.; Troyan, I. A.; Chow, P.; Xiao, Y.

    2018-02-01

    The magnetic properties of the α-Fe2O3 hematite at a high hydrostatic pressure have been studied by synchrotron Mössbauer spectroscopy (nuclear forward scattering (NFS)) on iron nuclei. Time-domain NFS spectra of hematite have been measured in a diamond anvil cell in the pressure range of 0-72 GPa and the temperature range of 36-300 K in order to study the magnetic properties at a phase transition near a critical pressure of 50 GPa. In addition, Raman spectra at room temperature have been studied in the pressure range of 0-77 GPa. Neon has been used as a pressure-transmitting medium. The appearance of an intermediate electronic state has been revealed at a pressure of 48 GPa. This state is probably related to the spin crossover in Fe3+ ions at their transition from the high-spin state (HS, S = 5/2) to a low-spin one (LS, S = 1/2). It has been found that the transient pressure range of the HS-LS crossover is extended from 48 to 55 GPa and is almost independent of the temperature. This surprising result differs fundamentally from other cases of the spin crossover in Fe3+ ions observed in other crystals based on iron oxides. The transition region of spin crossover appears because of thermal fluctuations between HS and LS states in the critical pressure range and is significantly narrowed at cooling because of the suppression of thermal excitations. The magnetic P- T phase diagram of α-Fe2O3 at high pressures and low temperatures in the spin crossover region has been constructed according to the results of measurements.

  19. High-pressure cell for luminescence studies of condensed phases at low temperatures

    International Nuclear Information System (INIS)

    Variano, B.F.; Brenner, H.C.; Daniels, W.B.

    1986-01-01

    A clamped optical cell for high-pressure low-temperature fluorescence and phosphorescence studies is described. A particular innovation is the use of a bifurcated fiber-optic lightguide to enable sample illumination and emission collection with a single optical window. This very simple type of cell is adaptable to a variety of optical setups and is easily assembled and disassembled for sample mounting

  20. The corrosion rate measurement of Inconel 690 on high temperature and pressure by using CMS100

    International Nuclear Information System (INIS)

    Sriyono; Satmoko, Ari; Febrianto; Hidayati, N R; Arifal; Sumarno, Ady; Handoyo, Ismu; Prasetjo, Joko

    1999-01-01

    The corrosion rate measurement of Inconel 690 on high temperature and pressure had been done. By using an Autoclave, and temperature can be simulated. For reducing the pressure on Autoclave so its can be measure by Corrosion Measurement System 100(CMS100), the electrodes placement had designed and fabrication on the cover of Autoclave. The electrodes of CMS100 are reference electrode, working electrodes and counter electrodes. The electrodes placement are made and and designed on two packages, these are Salt bridge and Counter-specimen placement. From the result of testing these both of placement are able to 90 bar (pressure) and 280 C (temperature) operation rate measurement was done on temperature variation from 150 0C, 190 0C, 200 0C, 210 0C, 220 0C and 230 0C, and the solution is 0.1 ppm chloride. The pressure experiment is the pressure, which occurred in Autoclave. From the Tafel analysis, even through very little The corrosion current increased from 150 C to 230 C it is 2,54x10-10 a/cm2 to 1,62x10-9 A/cm2, but the the corrosion rate is still zero

  1. Temperature dependence of thermal pressure for NaCl

    Science.gov (United States)

    Singh, Chandra K.; Pande, Brijesh K.; Pandey, Anjani K.

    2018-05-01

    Engineering applications of the materials can be explored upto the desired limit of accuracy with the better knowledge of its mechanical and thermal properties such as ductility, brittleness and Thermal Pressure. For the resistance to fracture (K) and plastic deformation (G) the ratio K/G is treated as an indication of ductile or brittle character of solids. In the present work we have tested the condition of ductility and brittleness with the calculated values of K/G for the NaCl. It is concluded that the nature of NaCl can be predicted upto high temperature simply with the knowledge of its elastic stiffness constant only. Thermoelastic properties of materials at high temperature is directly related to thermal pressure and volume expansion of the materials. An expression for the temperature dependence of thermal pressure is formulated using basic thermodynamic identities. It is observed that thermal pressure ΔPth calculated for NaCl by using Kushwah formulation is in good agreement with the experimental values also the thermal pressure increases with the increase in temperature.

  2. High Pressure-Temperature Phase Diagram of 1,1-diamino-2,2-dinitroethylene

    Science.gov (United States)

    Bishop, Matthew; Chellappa, Raja; Liu, Zhenxian; Preston, Daniel; Sandstrom, Mary; Dattelbaum, Dana; Vohra, Yogesh; Velisavljevic, Nenad

    2013-06-01

    1,1-diamino-2,2-dinitroethelyne (FOX-7) is a less sensitive energetic material with performance comparable to commonly used secondary explosives such as RDX and HMX. At ambient pressure, FOX-7 exhibits complex polymorphism with at least three structurally distinct phases (α, β, and γ) . In this study, we have investigated the high P-T stability of FOX-7 polymorphs using synchrotron mid-infrared (MIR) spectroscopy. At ambient pressure, our MIR spectra confirmed the known α --> β (110 °C) and β --> γ (160 °C) phase transitions; as well as, indicated an additional phase transition, γ --> δ (210°C), with the δ phase being stable up to 250 °C prior to melt/decomposition. In situ MIR spectra obtained during isobaric heating at 0.9 GPa revealed that the α --> β transition occurs at 180 °C, while β --> β + δ phase transition shifted to 300 °C with suppression of γ phase. Decomposition was observed above 325 °C. Based on multiple high P-T measurements, we have established the first high P-T phase diagram of FOX-7. This work was, in part, supported by the US DOE under contract No. DE-AC52-06NA25396 and Science Campaign 2 Program. MB acknowledges additional support from the NSF BD program. Use of NSLS (DE-AC02-98CH10886) beamline U2A (COMPRES, No.EAR01-35554, CDAC).

  3. Thermal expansivity and bulk modulus of ZnO with NaCl-type cubic structure at high pressures and temperatures

    International Nuclear Information System (INIS)

    Sun Xiaowei; Liu Zijiang; Chen Qifeng; Chu Yandong; Wang Chengwei

    2006-01-01

    The thermal expansivity and bulk modulus of ZnO with NaCl-type cubic structure were estimated by using the constant temperature and pressure molecular dynamics technique with effective pair potentials which consist of the Coulomb, dispersion, and repulsion interaction at high pressures and temperatures. It is shown that the calculated thermodynamic parameters including linear thermal expansion coefficient, isothermal bulk modulus and its pressure derivative are in good agreement with the available experimental data and the latest theoretical results. At an extended pressure and temperature ranges, linear thermal expansion coefficient and isothermal bulk modus have also been predicted. The thermodynamic properties of ZnO with NaCl-type cubic structure are summarized in the pressure 0-150 GPa ranges and the temperature up to 3000 K

  4. Plasma Jet Printing and in Situ Reduction of Highly Acidic Graphene Oxide.

    Science.gov (United States)

    Dey, Avishek; Krishnamurthy, Satheesh; Bowen, James; Nordlund, Dennis; Meyyappan, M; Gandhiraman, Ram P

    2018-05-23

    Miniaturization of electronic devices and the advancement of Internet of Things pose exciting challenges to develop technologies for patterned deposition of functional nanomaterials. Printed and flexible electronic devices and energy storage devices can be embedded onto clothing or other flexible surfaces. Graphene oxide (GO) has gained much attention in printed electronics due its solution processability, robustness, and high electrical conductivity in the reduced state. Here, we introduce an approach to print GO films from highly acidic suspensions with in situ reduction using an atmospheric pressure plasma jet. Low-temperature plasma of a He and H 2 mixture was used successfully to reduce a highly acidic GO suspension (pH < 2) in situ during deposition. This technique overcomes the multiple intermediate steps required to increase the conductivity of deposited GO. X-ray spectroscopic studies confirmed that the reaction intermediates and the concentration of oxygen functionalities bonded to GO have been reduced significantly by this approach without any additional steps. Moreover, the reduced GO films showed enhanced conductivity. Hence, this technique has a strong potential for printing conducting patterns of GO for a range of large-scale applications.

  5. Cryogenic, Absolute, High Pressure Sensor

    Science.gov (United States)

    Chapman, John J. (Inventor); Shams. Qamar A. (Inventor); Powers, William T. (Inventor)

    2001-01-01

    A pressure sensor is provided for cryogenic, high pressure applications. A highly doped silicon piezoresistive pressure sensor is bonded to a silicon substrate in an absolute pressure sensing configuration. The absolute pressure sensor is bonded to an aluminum nitride substrate. Aluminum nitride has appropriate coefficient of thermal expansion for use with highly doped silicon at cryogenic temperatures. A group of sensors, either two sensors on two substrates or four sensors on a single substrate are packaged in a pressure vessel.

  6. Cryogenic High Pressure Sensor Module

    Science.gov (United States)

    Chapman, John J. (Inventor); Shams, Qamar A. (Inventor); Powers, William T. (Inventor)

    1999-01-01

    A pressure sensor is provided for cryogenic, high pressure applications. A highly doped silicon piezoresistive pressure sensor is bonded to a silicon substrate in an absolute pressure sensing configuration. The absolute pressure sensor is bonded to an aluminum nitride substrate. Aluminum nitride has appropriate coefficient of thermal expansion for use with highly doped silicon at cryogenic temperatures. A group of sensors, either two sensors on two substrates or four sensors on a single substrate are packaged in a pressure vessel.

  7. Neutron powder diffraction under high pressure at J-PARC

    International Nuclear Information System (INIS)

    Utsumi, Wataru; Kagi, Hiroyuki; Komatsu, Kazuki; Arima, Hiroshi; Nagai, Takaya; Okuchi, Takuo; Kamiyama, Takashi; Uwatoko, Yoshiya; Matsubayashi, Kazuyuki; Yagi, Takehiko

    2009-01-01

    It is expected that high-pressure material science and the investigation of the Earth's interior will progress greatly using the high-flux pulse neutrons of J-PARC. In this article, we introduce our plans for in situ neutron powder diffraction experiments under high pressure at J-PARC. The use of three different types of high-pressure devices is planned; a Paris-Edinburgh cell, a new opposed-anvil cell with a nano-polycrystalline diamond, and a cubic anvil high-pressure apparatus. These devices will be brought to the neutron powder diffraction beamlines to conduct a 'day-one' high-pressure experiment. For the next stage of research, we propose construction of a dedicated beamline for high-pressure material science. Its conceptual designs are also introduced here.

  8. Study of Raman Spectroscopy on Phase Relations of CaCO3 at High Temperature and High Pressure

    Science.gov (United States)

    Li, M.; Zheng, H.; Duan, T.

    2006-05-01

    Laser Raman Spectroscopy was used to study phase relations between calcite I, calcite II and aragonite at high pressure and high temperature. The experiment was performed in an externally heated Basselt type diamond anvil cell (DAC). Natural calcite (calcite I) was used as starting mineral. The sample and a small chip of quartz were loaded in a cavity (300 μm in diameter and 250 μm in depth) in a rhenium gasket. The Na2CO3 aqueous solution of 1mol/L was also loaded as a pressure medium to yield hydrostatic pressure. The whole assembly was pressurized first and then heated stepwise to 400°C. Pressure and temperature in the chamber were determined by the shift of Raman band at 464 cm-1 of quartz and by NiCr-NiSi thermocouple, respectively. The Raman spectra were measured by a Renishaw 1000 spetrometer with 50 mW of 514.5nm argon-ion laser as the excitation light source. The slit width was 50 μm and the corresponding resolution was ±1 cm-1. From the experiments, we observed the phase transitions between calcite I and calcite II, calcite I and aragonite, calcite II and aragonite, respectively. Our data showed a negative slope for the boundary between calcite I and calcite II, which was similar to Bridgman's result, although Hess et al. gave a positive slope. The boundary with a negative slope for calcite II and aragonite was also defined, which had never been done before. And all these data can yield a more complete phase diagram of CaCO3 than the studies of Hess et al. and Suito et al.Reference:Bridgeman P. W.(1939) Journal: American Journal of Science, Vol. 237, p. 7-18Bassett W. A. et al. (1993) Journal: Review of Scientific Instruments, Vol. 64, p. 2340-2345Suito K. et al. (2001) Journal: American Mineralogist, Vol. 86, p. 997- 1002Hess N. J. et al. (1991) In A. K. Singh, Ed., Recent Trends in High Pressure Research; Proc. X IIIth AIRAPT International Conference on High Pressure Science and Technology, p. 236-241. Oxford & IBH Publishing Co. Pvt, Ltd., New

  9. A method enabling simultaneous pressure and temperature measurement using a single piezoresistive MEMS pressure sensor

    International Nuclear Information System (INIS)

    Frantlović, Miloš; Stanković, Srđan; Jokić, Ivana; Lazić, Žarko; Smiljanić, Milče; Obradov, Marko; Vukelić, Branko; Jakšić, Zoran

    2016-01-01

    In this paper we present a high-performance, simple and low-cost method for simultaneous measurement of pressure and temperature using a single piezoresistive MEMS pressure sensor. The proposed measurement method utilizes the parasitic temperature sensitivity of the sensing element for both pressure measurement correction and temperature measurement. A parametric mathematical model of the sensor was established and its parameters were calculated using the obtained characterization data. Based on the model, a real-time sensor correction for both pressure and temperature measurements was implemented in a target measurement system. The proposed method was verified experimentally on a group of typical industrial-grade piezoresistive sensors. The obtained results indicate that the method enables the pressure measurement performance to exceed that of typical digital industrial pressure transmitters, achieving at the same time the temperature measurement performance comparable to industrial-grade platinum resistance temperature sensors. The presented work is directly applicable in industrial instrumentation, where it can add temperature measurement capability to the existing pressure measurement instruments, requiring little or no additional hardware, and without adverse effects on pressure measurement performance. (paper)

  10. 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.

  11. A new technique for obtaining high-resolution pore pressure records in thick claystone aquitards and its use to determine in situ compressibility

    Science.gov (United States)

    Smith, Laura A.; van der Kamp, Garth; Jim Hendry, M.

    2013-02-01

    Laboratory tests are commonly used to determine properties (vertical compressibility, α; specific storage, SS; and vertical hydraulic conductivity, Kv) of claystone aquitards; however, whether data representative of in situ conditions can be obtained from disturbed samples is questionable. Here, we present a method to determine the in situ α and SS of a thick sequence of Cretaceous aged claystone by estimating the loading efficiency (γ) of a formation from pore pressure responses to barometric pressure fluctuations. We installed 10 vibrating wire pressure transducers at different depths (25-325 m below ground) in a thick claystone aquitard by placing them directly within the cement-bentonite grout. Two years of continuous transducer records using this method appeared to provide pore pressure data with a resolution of better than one part in 105, equivalent to millimeter of hydraulic head change. Pore pressure responses to barometric pressure changes, earth tides, and precipitation events can be clearly identified, and the barometric responses can be easily analyzed. The resulting values of γ (0.6-0.93), α (2.5 × 10-7 to 2.2 × 10-6 kPa-1), and SS (2.6 × 10-5 to 4.5 × 10-6 m-1) all decrease with depth. The results are comparable with the limited existing data for in situ estimates of SS and are as much as an order of magnitude smaller than laboratory estimates of SS for similar aquitard deposits. Our findings suggest that the fully grouted transducer method can provide an accurate and reliable means to monitor pore pressure changes and to determine in situ parameters for bedrock aquitard systems.

  12. The Corrosion Rate Measurement of Inconel 690 on High Temperature andPressure by Using CMS100

    International Nuclear Information System (INIS)

    Sriyono; Febrianto

    2000-01-01

    The corrosion rate measurement of Inconel 690 on high temperature andpressure had been done. By using an Autoclave, pressure and temperature canbe simulated. The environment of this experiment is 0.1 ppm of chloridesolution, which permit to dissolved in secondary cooling of steam generator.The corrosion rate measurement was done on temperature between 150 o C and230 o C with step 10 o C. Pressure experiment is the pressure, which occurredin Autoclave. Corrosion rate is measured by CMS100. From the Tafel analysis,corrosion rate of Inconel 690 linearity increased from 6.548 x 10 -5 mpy to4.331 x 10 -4 mpy. It concludes that Inconel 690 is resist on corrosionenvironment, so it's most using on the fabrication of steam generator tubeson the advanced power plant. (author)

  13. H2O temperature sensor for low-pressure flames using tunable diode laser absorption near 2.9 νm

    KAUST Repository

    Li, Sijie

    2011-10-19

    Making use of a newly available rapid-tuning diode laser operating at wavelengths up to 2.9 νm, an absorption-based temperature sensor was developed for in situ measurements in low-pressure flames. Based on the systematic analysis of H2O vapor transitions in the fundamental vibrational bands (ν1 and ν3) of H2O in the range of 2.5-3.0 νm, an optimal closely-spaced spectral line pair near 2.9 νm was selected for its temperature sensitivity in the range of 1000-2500 K. The narrow-linewidth room-temperature laser was scanned repetitively across these spectral features at 5 kHz, enabling fast, accurate temperature sensing. Use of the temperature sensor was investigated in low-pressure flames supported on a McKenna burner at 15, 25 and 60 Torr. To avoid absorption by the cold gases in the flame edges and the recirculation region between the burner and the vacuum chamber wall, a variable-path in situ probe was designed and an optimal path length was determined to accurately measure the flame centerline temperature. Different flame conditions were investigated to illustrate the potential of this sensor system for sensitive measurements of combustion temperature in low-pressure flames. © 2011 IOP Publishing Ltd.

  14. Pressure effect on crystallization temperature in Zr70Pd30 metallic glass

    DEFF Research Database (Denmark)

    Jiang, Jianzhong; Jeppesen, S; Saida, J.

    2004-01-01

    The pressure effect on amorphous-to-quasicrystalline-to-intermetallic phase transformations in a Zr70Pd30 metallic glass has been investigated by in situ x-ray diffraction measurements using synchrotron radiation. It is found that the glass crystallizes in two steps: (1) amorphous...... temperature for the formation of quasicrystals has been further discussed with the nucleation theory. ©2004 American Institute of Physics....

  15. Root cause analysis of oxide scale forming and shedding in high temperature reheater of a 200MW super high pressure boiler

    Science.gov (United States)

    Bo, Jiang; Hao, Weidong; Hu, Zhihong; Liu, Fuguo

    2015-12-01

    In order to solve the problem of over temperature tube-burst caused by oxide scale shedding and blocking tubes of high temperature reheater of a 200MW super high pressure power plant boiler, this paper expounds the mechanism of scale forming and shedding, and analyzes the probable causes of the tube-burst failure. The results show that the root cause of scale forming is that greater steam extraction flow after reforming of the second extraction leads to less steam flow into reheater, which causes over temperature to some of the heated tubes; and the root cause of scale shedding is that long term operation in AGC-R mode brings about great fluctuations of unit load, steam temperature and pressure, accelerating scale shedding. In conclusion, preventive measures are drawn up considering the operation mode of the unit.

  16. Platinum Iron Intermetallic Nanoparticles Supported on Carbon Formed In Situ by High-Pressure Pyrolysis for Efficient Oxygen Reduction

    DEFF Research Database (Denmark)

    Hu, Yang; Jensen, Jens Oluf; Zhang, Wei

    2016-01-01

    Carbon-supported PtFe alloy catalysts are synthesized by the one-step, high-temperature pyrolysis of Pt, Fe, and C precursors. As a result of the high temperature, the formed PtFe nanoparticles possess highly ordered, face-centered tetragonal, intermetallic structures with a mean size of ≈11.8 nm....... At 0.9 V versus the reversible hydrogen electrode, the PtFe nanoparticles show a 6.8 times higher specific activity than the reference Pt/C catalyst towards the oxygen reduction reaction (ORR) as well as excellent stability, most likely because of the durable intermetallic structure and the preleaching...... treatment of the catalyst. During these preliminary syntheses, we found that a portion of the PtFe nanoparticles is buried in the in situ formed carbon phase, which limits Pt utilization in the catalyst and results in a mass-specific activity equivalent to the commercial Pt/C catalyst. Moreover...

  17. In Situ Studies of the Temperature-Dependent Surface Structure and Chemistry of Single-Crystalline (001)-Oriented La 0.8 Sr 0.2 CoO 3−δ Perovskite Thin Films

    KAUST Repository

    Feng, Zhenxing; Crumlin, Ethan J.; Hong, Wesley T.; Lee, Dongkyu; Mutoro, Eva; Biegalski, Michael D.; Zhou, Hua; Bluhm, Hendrik; Christen, Hans M.; Shao-Horn, Yang

    2013-01-01

    Perovskites are used to promote the kinetics of oxygen electrocatalysis in solid oxide fuel cells and oxygen permeation membranes. Little is known about the surface structure and chemistry of perovskites at high temperatures and partial oxygen pressures. Combining in situ X-ray reflectivity (XRR) and in situ ambient pressure X-ray photoelectron spectroscopy (APXPS), we report, for the first time, the evolution of the surface structure and chemistry of (001)-oriented perovskite La0.8Sr0.2CoO 3-δ (LSC113) and (La0.5Sr 0.5)2CoO4+δ (LSC214)-decorated LSC113 (LSC113/214) thin films as a function of temperature. Heating the (001)-oriented LSC113 surface leads to the formation of surface LSC214-like particles, which is further confirmed by ex situ Auger electron spectroscopy (AES). In contrast, the LSC113/214 surface, with activities much higher than that of LSC 113, is stable upon heating. Combined in situ XRR and APXPS measurements support that Sr enrichment may occur at the LSC113 and LSC214 interface, which can be responsible for its markedly enhanced activities. © 2013 American Chemical Society.

  18. In Situ Studies of the Temperature-Dependent Surface Structure and Chemistry of Single-Crystalline (001)-Oriented La 0.8 Sr 0.2 CoO 3−δ Perovskite Thin Films

    KAUST Repository

    Feng, Zhenxing

    2013-05-02

    Perovskites are used to promote the kinetics of oxygen electrocatalysis in solid oxide fuel cells and oxygen permeation membranes. Little is known about the surface structure and chemistry of perovskites at high temperatures and partial oxygen pressures. Combining in situ X-ray reflectivity (XRR) and in situ ambient pressure X-ray photoelectron spectroscopy (APXPS), we report, for the first time, the evolution of the surface structure and chemistry of (001)-oriented perovskite La0.8Sr0.2CoO 3-δ (LSC113) and (La0.5Sr 0.5)2CoO4+δ (LSC214)-decorated LSC113 (LSC113/214) thin films as a function of temperature. Heating the (001)-oriented LSC113 surface leads to the formation of surface LSC214-like particles, which is further confirmed by ex situ Auger electron spectroscopy (AES). In contrast, the LSC113/214 surface, with activities much higher than that of LSC 113, is stable upon heating. Combined in situ XRR and APXPS measurements support that Sr enrichment may occur at the LSC113 and LSC214 interface, which can be responsible for its markedly enhanced activities. © 2013 American Chemical Society.

  19. Computational simulation of reactive species production by methane-air DBD at high pressure and high temperature

    Science.gov (United States)

    Takana, H.; Tanaka, Y.; Nishiyama, H.

    2012-01-01

    Computational simulations of a single streamer in DBD in lean methane-air mixture at pressure of 1 and 3 atm and temperature of 300 and 500 K were conducted for plasma-enhanced chemical reactions in a closed system. The effects of surrounding pressure and temperature are characterized for reactive species production by a DBD discharge. The results show that the production characteristics of reactive species are strongly influenced by the total gas number density and the higher concentration of reactive species are produced at higher pressure and lower gas temperature for a given initial reduced electric field.

  20. Frictional characteristics of stainless steel 440C lubricated with water at pressurized high temperature

    International Nuclear Information System (INIS)

    Kim, E. H.; Lee, J. S.; Kim, J. H.; Kim, J. I.

    2001-01-01

    The fatigue life of stainless steel bearings is one of the most critical factors to determine the performance of the driving system. Because the bearings which are installed on the driving mechanism in the nuclear reactor are operated at high temperature and high pressure and especially lubricated with water with low viscosity, the friction and wear characteristics of the bearing material should be investigated thoroughly. In many control element drive mechanisms in the nuclear reactor the support bearings are made of the stainless steel and the sliding bearing ceramic material mainly. This study is focused on the characteristics of support bearing which may be used in the SMART. The ball bearings are made of standardized 440C stainless steel, and it supports thrust load including the weight of the driving system and external force. The friction and wear characteristics of this material operating under severe lubrication condition are not well known yet, however it will be changed with respect to temperature and boundary pressure. In this paper the friction characteristics are investigated experimentally using the reciprocating tribometer which can simulate the SMART operating conditions. Highly purified water is used as lubricant, and the water is warmed up and pressurized. Friction forces on the reciprocating specimens are measured insitu strain gages

  1. High-pressure behavior of synthetic mordenite-Na. An in situ single-crystal synchrotron X-ray diffraction study

    Energy Technology Data Exchange (ETDEWEB)

    Lotti, Paolo; Merlini, Marco [Univ. degli Studi di Milano, (Italy). Dipt. di Scienze della Terra; Gatta, G. Diego [Univ. degli Studi di Milano, (Italy). Dipt. di Scienze della Terra; CNR, Bari (Italy). Int. di Cristallografia; Liermann, Hanns-Peter [DESY, Hamburg (Germany). Photon Sciences

    2015-05-01

    The high-pressure behavior of a synthetic mordenite-Na (space group: Cmcm or Cmc2{sub 1}) was studied by in situ single-crystal synchrotron X-ray diffraction with a diamond anvil cell up to 9.22(7) GPa. A phase transition, likely displacive in character, occurred between 1.68(7) and 2.70(8) GPa, from a C-centered to a primitive space group: possibly Pbnm, Pbnn or Pbn2{sub 1}. Fitting of the experimental data with III-BM equations of state allowed to describe the elastic behavior of the high-pressure polymorph with a primitive lattice. A very high volume compressibility [K{sub V0} = 25(2) GPa, β{sub V0} = 1/K{sub V0} = 0.040(3) GPa{sup -1}; K{sub V}' = (∂K{sub V}/∂P){sub T} = 2.0(3)], coupled with a remarkable elastic anisotropy (β{sub b}>>β{sub c}>β{sub a}), was found. Interestingly, the low-P and high-P polymorphs show the same anisotropic compressional scheme. A structure collapse was not observed up to 9.22(7) GPa, even though a strong decrease of the number of observed reflections at the highest pressures suggests an impending amorphization. The structure refinements performed at room-P, 0.98(2) and 1.68(7) GPa allowed to describe, at a first approximation, the mechanisms that govern the framework deformation in the low-P regime: the bulk compression is strongly accommodated by the increase of the ellipticity of the large 12-membered ring channels running along [001].

  2. In situ electrical conductivity measurements of H{sub 2}O under static pressure up to 28 GPa

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Bao, E-mail: liubao@nedu.edu.cn [Institute of Materials Physics, College of Science, Northeast Dianli University, Jilin 132012 (China); State Key Laboratory of Superhard Materials, Institute of Atomic and Molecular Physics, Jilin University, Changchun 130012 (China); Gao, Yang [State Key Laboratory of Superhard Materials, Institute of Atomic and Molecular Physics, Jilin University, Changchun 130012 (China); Department of Mechanical Engineering, Texas Tech University, Lubbock, TX 79409 (United States); Han, Yonghao [State Key Laboratory of Superhard Materials, Institute of Atomic and Molecular Physics, Jilin University, Changchun 130012 (China); Ma, Yanzhang [Department of Mechanical Engineering, Texas Tech University, Lubbock, TX 79409 (United States); Gao, Chunxiao, E-mail: cc060109@qq.com [State Key Laboratory of Superhard Materials, Institute of Atomic and Molecular Physics, Jilin University, Changchun 130012 (China)

    2016-08-26

    Highlights: • We conduct in situ electrical conductivity measurements on water in a diamond anvil cell (DAC) under high pressure up to 28 GPa and study the electrical transport properties of water and ices. • In liquid state, the increasing rate of electrical conductivity with pressure is slower than that obtained in shock-waves measurements. • In solid phase, the relationship between electrical conductivity and pressure is discontinuous, which is corresponding to phase transformation from ice VIII to ice VII. • The difference in electrical conductivity of VI, VII, and VIII may associate with different orientational ordering in these ices. • The electrical conduction in these ices is dominated by already existing ions and Bjerrum defects, which play an important role in electrical transport properties of ices. - Abstract: The in situ electrical conductivity measurements on water in both solid state and liquid state were performed under pressure up to 28 GPa and temperature from 77 K to 300 K using a microcircuit fabricated on a diamond anvil cell (DAC). Water chemically ionization mainly contributes to electrical conduction in liquid state, which is in accord with the results obtained under dynamic pressure. Energy band theory of liquid water was used to understand effect of static pressure on electrical conduction of water. The electric conductivity of H{sub 2}O decreased discontinuously by four orders of magnitude at 0.7–0.96 GPa, indicating water frozen at this P–T condition. Correspondingly, the conduction of H{sub 2}O in solid state is determined by arrangement and bending of H-bond in ice VI and ice VII. Based on Jaccard theory, we have concluded that the charge carriers of ice are already existing ions and Bjerrum defects.

  3. Stability of very-high pressure arc discharges against perturbations of the electron temperature

    Energy Technology Data Exchange (ETDEWEB)

    Benilov, M. S. [Departamento de Fisica, Ciencias Exactas e Engenharia, Universidade da Madeira, Largo do Municipio, Funchal 9000 (Portugal); Hechtfischer, U. [Philips Lighting, BU Automotive Lamps, Technology, Philipsstrasse 8, Aachen 52068 (Germany)

    2012-04-01

    We study the stability of the energy balance of the electron gas in very high-pressure plasmas against longitudinal perturbations, using a local dispersion analysis. After deriving a dispersion equation, we apply the model to a very high-pressure (100 bar) xenon plasma and find instability for electron temperatures, T{sub e}, in a window between 2400 K and 5500-7000 K x 10{sup 3} K, depending on the current density (10{sup 6}-10{sup 8} A/m{sup 2}). The instability can be traced back to the Joule heating of the electron gas being a growing function of T{sub e}, which is due to a rising dependence of the electron-atom collision frequency on T{sub e}. We then analyze the T{sub e} range occurring in very high-pressure xenon lamps and conclude that only the near-anode region exhibits T{sub e} sufficiently low for this instability to occur. Indeed, previous experiments have revealed that such lamps develop, under certain conditions, voltage oscillations accompanied by electromagnetic interference, and this instability has been pinned down to the plasma-anode interaction. A relation between the mechanisms of the considered instability and multiple anodic attachments of high-pressure arcs is discussed.

  4. High-Pressure Oxygen Generation for Outpost EVA Study

    Science.gov (United States)

    Jeng, Frank F.; Conger, Bruce; Ewert, Michael K.; Anderson, Molly S.

    2009-01-01

    The amount of oxygen consumption for crew extravehicular activity (EVA) in future lunar exploration missions will be significant. Eight technologies to provide high pressure EVA O2 were investigated. They are: high pressure O2 storage, liquid oxygen (LOX) storage followed by vaporization, scavenging LOX from Lander followed by vaporization, LOX delivery followed by sorption compression, water electrolysis followed by compression, stand-alone high pressure water electrolyzer, Environmental Control and Life Support System (ECLSS) and Power Elements sharing a high pressure water electrolyzer, and ECLSS and In-Situ Resource Utilization (ISRU) Elements sharing a high pressure electrolyzer. A trade analysis was conducted comparing launch mass and equivalent system mass (ESM) of the eight technologies in open and closed ECLSS architectures. Technologies considered appropriate for the two architectures were selected and suggested for development.

  5. A noncontact wireless passive radio frequency (RF) resonant pressure sensor with optimized design for applications in high-temperature environments

    International Nuclear Information System (INIS)

    Li, Chen; Tan, Qiulin; Xiong, Jijun; Jia, Pinggang; Hong, Yingping; Ren, Zhong; Luo, Tao; Liu, Jun; Xue, Chenyang; Zhang, Wendong

    2014-01-01

    A noncontact wireless passive pressure sensor based on alumina ceramic for pressure measurement is presented in this paper. A faithful pressure signal in harsh environment is captured through wireless sensing, and a novel antenna design method is developed to increase the measurement distance between the antenna and the sensor. The sensor is fabricated using a novel no-co-fired technology, and the properties of the alumina ceramic and platinum ensure the feasibility of the sensor in high-temperature environments. The experimental results show that the coupled distance between the antenna and the sensor can be up to 5.5 cm, and the designed sensor, featuring improved structural parameters, has a high responsivity (15.5 kHz kPa −1 ) in a pressure environment at room temperature. The sensor can be coupled with the antenna at 850 °C, which verifies the feasibility in high-temperature environments. (paper)

  6. High Temperature Heat Exchanger Design and Fabrication for Systems with Large Pressure Differentials

    Energy Technology Data Exchange (ETDEWEB)

    Chordia, Lalit [Thar Energy, LLC, Pittsburgh, PA (United States); Portnoff, Marc A. [Thar Energy, LLC, Pittsburgh, PA (United States); Green, Ed [Thar Energy, LLC, Pittsburgh, PA (United States)

    2017-03-31

    The project’s main purpose was to design, build and test a compact heat exchanger for supercritical carbon dioxide (sCO2) power cycle recuperators. The compact recuperator is required to operate at high temperature and high pressure differentials, 169 bar (~2,500 psi), between streams of sCO2. Additional project tasks included building a hot air-to-sCO2 Heater heat exchanger (HX) and design, build and operate a test loop to characterize the recuperator and heater heat exchangers. A novel counter-current microtube recuperator was built to meet the high temperature high differential pressure criteria and tested. The compact HX design also incorporated a number of features that optimize material use, improved reliability and reduced cost. The air-to-sCO2 Heater HX utilized a cross flow, counter-current, micro-tubular design. This compact HX design was incorporated into the test loop and exceeded design expectations. The test loop design to characterize the prototype Brayton power cycle HXs was assembled, commissioned and operated during the program. Both the prototype recuperator and Heater HXs were characterized. Measured results for the recuperator confirmed the predictions of the heat transfer models developed during the project. Heater HX data analysis is ongoing.

  7. Time-resolved x-ray diffraction measurement of C{sub 60} under high pressure and temperature using synchrotron radiation

    Energy Technology Data Exchange (ETDEWEB)

    Horikawa, T [Graduate School of Engineering Science, Osaka University, Toyonaka, Osaka 560-8531 (Japan); Suito, K [Graduate School of Engineering Science, Osaka University, Toyonaka, Osaka 560-8531 (Japan); Kobayashi, M [Graduate School of Engineering Science, Osaka University, Toyonaka, Osaka 560-8531 (Japan); Onodera, A [Graduate School of Engineering Science, Osaka University, Toyonaka, Osaka 560-8531 (Japan)

    2002-11-11

    C{sub 60} has been studied by means of time-resolved x-ray diffraction measurements using synchrotron radiation. Diffraction patterns were recorded at intervals of 1-10 min for samples under high pressure (12.5 and 14.3 GPa) and high temperature (up to 800 deg. C) for, at the longest, 3 h. Time, pressure, and temperature dependences of the C{sub 60} structure are presented and the relevance to the hardness of materials derived from C{sub 60} is discussed.

  8. In Situ XRD Studies of ZnO/GaN Mixtures at High Pressure and High Temperature: Synthesis of Zn-Rich (Ga1-xZnx)(N1-xOx) Photocatalysts

    Energy Technology Data Exchange (ETDEWEB)

    Rodriguez, J.A.; Chen, H.; Wang, L.; Bai, J.; Hanson, J.C.; Warren, J.B.; Muckerman, J.T.; Fujita, E.

    2010-02-04

    The high-pressure, high-temperature conditions for the synthesis of Zn-rich (Ga{sub 1-x}Zn{sub x})(N{sub 1-x}O{sub x}) solid solutions from mixtures of ZnO/GaN were explored using synchrotron-based in situ time-resolved X-ray diffraction (XRD). Following a new synthetic path, (Ga{sub 1-x}Zn{sub x})(N{sub 1-x}O{sub x}) solid solutions with a Zn content up to 75% were prepared for the first time. The structures of the (Ga{sub 1-x}Zn{sub x})(N{sub 1-x}O{sub x}) solid solutions were characterized by XRD and X-ray absorption fine structure (XAFS) analyses and were in excellent agreement with the predictions of density functional calculations. These materials adopt a wurtzite crystal structure with metal-N or metal-O bond distances in the range of 1.95-1.98 {angstrom}. Although the (Ga{sub 1-x}Zn{sub x})(N{sub 1-x}O{sub x}) solid solutions seem to be stable over the full range of compositions, no ideal solid solution formation was observed. In all cases, the lattice parameters were larger than those of ideal solid solutions. The variation of the lattice parameter c showed an upward double bowing curve, as was predicted by theoretical calculations. Also, no ideal behavior was observed in the electronic properties of the (Ga{sub 1-x}Zn{sub x})(N{sub 1-x}O{sub x}) solid solutions. X-ray absorption spectra at the Zn and Ga K-edges of the (Ga{sub 1-x}Zn{sub x})(N{sub 1-x}O{sub x}) systems showed significant electronic perturbations with respect to ZnO and GaN. The synthesized (Ga{sub 1-x}Zn{sub x})(N{sub 1-x}O{sub x}) solid solution with a Zn content of 50% displayed the ability to absorb visible light well above 500 nm. This material has a great potential for splitting water under visible light irradiation. The availability of (Ga{sub 1-x}Zn{sub x})(N{sub 1-x}O{sub x}) solid solutions with a high Zn content opens the door to fully explore the application of these materials in photocatalysis.

  9. In Situ XRD Studies of ZnO/GaN Mixtures at High Pressure and High Temperature: Synthesis of Zn-Rich (Ga1-xZnx)(N1-xOx) Photocatalysts

    Energy Technology Data Exchange (ETDEWEB)

    Chen, H.; Wang, L; Bai, J; Hanson, J; Warren, J; Muckerman, J; Fujita, E; Rodriguez, J

    2010-01-01

    The high-pressure, high-temperature conditions for the synthesis of Zn-rich (Ga{sub 1-x}Zn{sub x})(N{sub 1-x}O{sub x}) solid solutions from mixtures of ZnO/GaN were explored using synchrotron-based in situ time-resolved X-ray diffraction (XRD). Following a new synthetic path, (Ga{sub 1-x}Zn{sub x})(N{sub 1-x}O{sub x}) solid solutions with a Zn content up to {approx}75% were prepared for the first time. The structures of the (Ga{sub 1-x}Zn{sub x})(N{sub 1-x}O{sub x}) solid solutions were characterized by XRD and X-ray absorption fine structure (XAFS) analyses and were in excellent agreement with the predictions of density functional calculations. These materials adopt a wurtzite crystal structure with metal-N or metal-O bond distances in the range of 1.95-1.98 {angstrom}. Although the (Ga{sub 1-x}Zn{sub x})(N{sub 1-x}O{sub x}) solid solutions seem to be stable over the full range of compositions, no ideal solid solution formation was observed. In all cases, the lattice parameters were larger than those of ideal solid solutions. The variation of the lattice parameter c showed an upward double bowing curve, as was predicted by theoretical calculations. Also, no ideal behavior was observed in the electronic properties of the (Ga{sub 1-x}Zn{sub x})(N{sub 1-x}O{sub x}) solid solutions. X-ray absorption spectra at the Zn and Ga K-edges of the (Ga{sub 1-x}Zn{sub x})(N{sub 1-x}O{sub x}) systems showed significant electronic perturbations with respect to ZnO and GaN. The synthesized (Ga{sub 1-x}Zn{sub x})(N{sub 1-x}O{sub x}) solid solution with a Zn content of 50% displayed the ability to absorb visible light well above 500 nm. This material has a great potential for splitting water under visible light irradiation. The availability of (Ga{sub 1-x}Zn{sub x})(N{sub 1-x}O{sub x}) solid solutions with a high Zn content opens the door to fully explore the application of these materials in photocatalysis.

  10. 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.

  11. Penetration of hydrogen isotopes through EhI 698 alloy at high pressure and temperature

    International Nuclear Information System (INIS)

    Bystritskij, V.M.; Voznyak, Ya.; Granovskij, V.B.

    1986-01-01

    The paper deals with investigations of the process of hydrogen and deuterium penetration through the high-temperature alloy EhI-698 at a pressure up to 1 kbar and temperature up to 1050 K. Parameters of the process obey Sieverts's law and can be described by Arrenius's and Vant-Goff's equations. The obtained results lead to a conclusion that the alloy EhI-698 is good for vessels to be employed in hydrogen media

  12. High pressure in situ X-ray diffraction study of MnO to 137 GPa and comparison with shock compression experiment

    Science.gov (United States)

    Yagi, T.; Kondo, T.; Syono, Y.

    1998-07-01

    In order to clarify the nature of the phase transformation in MnO observed at around 90 GPa by shock compression experiment, high pressure in situ X-ray observations were carried out up to 137 GPa. Powdered sample was directly compressed in Mao-Bell type diamond anvil cell and X-ray experiments were carried out using angle dispersive technique by combining synchrotron radiation and imaging plate detector. Distortion of the B1 structured phase was observed above about 40 GPa, which continues to increase up to 90 GPa. Two discontinuous changes of the diffraction profiles were observed at around 90 GPa and 120 GPa. The nature of the intermediate phase between 90 GPa and 120 GPa is not clear yet. It is neither cesium chloride (B2) nor nickel arsenide (B8) structure. On the other hand, the diffraction profile above 120 GPa can be reasonably well explained by the B8 structure. High pressure phases above 90 GPa have metallic luster and all the transformations are reversible on release of pressure.

  13. 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.

  14. The synergy of corrosion and fretting wear process on Inconel 690 in the high temperature high pressure water environment

    Science.gov (United States)

    Wang, Zihao; Xu, Jian; Li, Jie; Xin, Long; Lu, Yonghao; Shoji, Tetsuo; Takeda, Yoichi; Otsuka, Yuichi; Mutoh, Yoshiharu

    2018-04-01

    The synergistic effect of corrosion and fretting process of the steam generator (SG) tube was investigated by using a self-designed high temperature test rig in this paper. The experiments were performed at 100°C , 200°C and 288°C , respectively. The fretting corrosion damage was studied by optical microscopy (OM), scanning electron microscope (SEM), energy dispersive spectrometer (EDS), Raman spectroscopy and auger electron spectroscopy (AES). The results demonstrated that the corrosion process in high temperature high pressure (HTHP) water environment had a distinct interaction with the fretting process of Inconel 690. With the increment of temperature, the damage mechanism changed from a simple mechanical process to a mechanochemical process.

  15. Design and Evaluation of a Pressure and Temperature Monitoring System for Pressure Ulcer Prevention

    Directory of Open Access Journals (Sweden)

    Farve Daneshvar Fard

    2014-08-01

    Full Text Available Introduction Pressure ulcers are tissue damages resulting from blood flow restriction, which occurs when the tissue is exposed to high pressure for a long period of time. These painful sores are common in patients and elderly, who spend extended periods of time in bed or wheelchair. In this study, a continuous pressure and temperature monitoring system was developed for pressure ulcer prevention. Materials and Methods The monitoring system consists of 64 pressure and 64 temperature sensors on a 40×50 cm2 sheet. Pressure and temperature data and the corresponding maps were displayed on a computer in real-time. Risk assessment could be performed by monitoring and recording absolute pressure and temperature values, as well as deviations over time. Furthermore, a posture detection procedure was proposed for sitting posture identification. Information about the patient’s movement history may help caregivers make informed decisions about the patient’s repositioning and ulcer prevention strategies. Results Steady temporal behaviour of the designed system and repeatability of the measurements were evaluated using several particular tests. The results illustrated that the system could be utilized for continuous monitoring of interface pressure and temperature for pressure ulcer prevention. Furthermore, the proposed method for detecting sitting posture was verified using a statistical analysis. Conclusion A continuous time pressure and temperature monitoring system was presented in this study. This system may be suited for pressure ulcer prevention given its feasibility for simultaneous monitoring of pressure and temperature and alarming options. Furthermore, a method for detecting different sitting postures was proposed and verified. Pressure ulcers in wheelchair-bound patients may be prevented using this sitting posture detection method.

  16. Effect of hydrogen pressure on free radicals in direct coal liquefaction/coprocessing

    Energy Technology Data Exchange (ETDEWEB)

    Seehra, M.S.; Ibrahim, M.M. [West Virginia Univ., Morgantown, WV (United States)

    1995-12-31

    The objective of this study was to investigate the coprocessing of coal with waste tires and commingled plastics and to characterize the relevant catalysts, using high pressure/high temperature in-situ ESR (Electron Spin Resonance) spectroscopy. The recent results from high pressure ESR spectroscopy are emphasized. During this period, considerable progress was made in developing the high pressure capabilities in in-situ ESR spectroscopy and new results carried out in 1000 psi of H{sub 2}gas are presented. In these experiments, sapphire tubes were used to contain the high pressures at temperatures up to 500{degrees}C. Results of the experiments carried out under 1000 psi of H{sub 2} are compared with those under 1000 psi of non-interacting argon and with the earlier experiments in flowing H{sub 2} gas where the volatiles are removed by the flowing gas. In these experiments, the free radical density N of the Blind Canyon coal was measured at each temperature and pressure by double integration of the ESR signal and calibrating it against a standard. The details of the experimental apparatus and procedures have been described in earlier publications.

  17. Pressure effects on Al89La6Ni5 amorphous alloy crystallization

    DEFF Research Database (Denmark)

    Zhuang, Yanxin; Jiang, Jianzhong; Zhou, T. J.

    2000-01-01

    The pressure effect on the crystallization of the Al89La6Ni5 amorphous alloy has been investigated by in situ high-pressure and high-temperature x-ray powder diffraction using synchrotron radiation. The amorphous alloy crystallizes in two steps in the pressure range studied (0-4 GPa). The first p...

  18. Macroscopic Expressions of Molecular Adiabatic Compressibility of Methyl and Ethyl Caprate under High Pressure and High Temperature

    Directory of Open Access Journals (Sweden)

    Fuxi Shi

    2014-01-01

    Full Text Available The molecular compressibility, which is a macroscopic quantity to reveal the microcompressibility by additivity of molecular constitutions, is considered as a fixed value for specific organic liquids. In this study, we introduced two calculated expressions of molecular adiabatic compressibility to demonstrate its pressure and temperature dependency. The first one was developed from Wada’s constant expression based on experimental data of density and sound velocity. Secondly, by introducing the 2D fitting expressions and their partial derivative of pressure and temperature, molecular compressibility dependency was analyzed further, and a 3D fitting expression was obtained from the calculated data of the first one. The third was derived with introducing the pressure and temperature correction factors based on analogy to Lennard-Jones potential function and energy equipartition theorem. In wide range of temperatures (293pressures (0.1

    pressure and temperature of molecular compressibility was certified.

  19. High Pressure and Temperature Core Formation as an Alternative to the "Late Veneer" Hypothesis

    Science.gov (United States)

    Righter, Kevin; Pando, K.; Humayun, M.; Danielson, L.

    2011-01-01

    The highly siderophile elements (HSE; Re, Au and the Platinum Group Elements - Pd Pt, Rh, Ru, Ir, Os) are commonly utilized to constrain accretion processes in terrestrial differentiated bodies due to their affinity for FeNi metal [1]. These eight elements exhibit highly siderophile behavior, but nonetheless have highly diverse metal-silicate partition coefficients [2]. Therefore the near chondritic relative concentrations of HSEs in the terrestrial and lunar mantles, as well as some other bodies, are attributed to late accretion rather than core formation [1]. Evaluation of competing theories, such as high pressure metal-silicate partitioning or magma ocean hypotheses has been hindered by a lack of relevant partitioning data for this group of eight elements. In particular, systematic studies isolating the effect of one variable (e.g. temperature or melt compositions) are lacking. Here we undertake new experiments on all eight elements, using Fe metal and FeO-bearing silicate melts at fixed pressure, but variable temperatures. These experiments, as well as some additional planned experiments should allow partition coefficients to be more accurately calculated or estimated at the PT conditions and compositions at which core formation is thought to have occurred.

  20. Properties of molecular solids and fluids at high pressures and temperatures. [Final report

    International Nuclear Information System (INIS)

    Etters, R.D.

    1985-01-01

    Equilibrium structures and orientations, lattice vibrational and librational model frequencies, intramolecular vibron mode frequencies, sound velocities, equations of state, compressibilities, and structural and orientational phase transitions in molecular solids are determined over a wide range of pressures and temperatures. In the high temperature fluid phase the equations of state, vibron frequencies, the melting transition, specific heats, compressibilities, second virial coefficients, viscosities and other transport properties, and the nature of orientational and magnetic correlations are determined. The techniques used include several strategies to optimize multi-dimensional functions as a means to determine equilibrium structures and orientations, self consistent phonon lattice dynamics methods, constant pressure and constant volume Monte-Carlo strategies with continuously deformable boundary conditions, mean field approximations, and classical perturbation methods. Systems studied include N 2 , O 2 , CO, CO 2 , F 2 , N 2 O, benzine, nitromethane, HCL, HBr, and H 2 . 50 refs., 4 figs

  1. High-pressure, ambient temperature hydrogen storage in metal-organic frameworks and porous carbon

    Science.gov (United States)

    Beckner, Matthew; Dailly, Anne

    2014-03-01

    We investigated hydrogen storage in micro-porous adsorbents at ambient temperature and pressures up to 320 bar. We measured three benchmark adsorbents: two metal-organic frameworks, Cu3(1,3,5-benzenetricarboxylate)2 [Cu3(btc)2; HKUST-1] and Zn4O(1,3,5-benzenetribenzoate)2 [Zn4O(btb)2; MOF-177], and the activated carbon MSC-30. In this talk, we focus on adsorption enthalpy calculations using a single adsorption isotherm. We use the differential form of the Claussius-Clapeyron equation applied to the Dubinin-Astakhov adsorption model to calculate adsorption enthalpies. Calculation of the adsorption enthalpy in this way gives a temperature independent enthalpy of 5-7 kJ/mol at the lowest coverage for the three materials investigated. Additionally, we discuss the assumptions and corrections that must be made when calculating adsorption isotherms at high-pressure and adsorption enthalpies.

  2. Modeling Study of High Pressure and High Temperature Reservoir Fluids

    DEFF Research Database (Denmark)

    Varzandeh, Farhad

    properties like saturation pressures, densities at reservoir temperature and Stock TankviOil (STO) densities, while keeping the n-alkane limit of the correlations unchanged. Apart from applying this general approach to PC-SAFT, we have also shown that the approach can be applied to classical cubic models...... approach to characterizing reservoir fluids for any EoS. The approach consists in developing correlations of model parameters first with a database for well-defined components and then adjusting the correlations with a large PVT database. The adjustment is made to minimize the deviation in key PVT...... method to SRK and PR improved the saturation pressure calculation in comparisonto the original characterization method for SRK and PR. Using volume translationtogether with the new characterization approach for SRK and PR gives comparable results for density and STO density to that of original...

  3. Structural stability at high pressure, electronic, and magnetic properties of BaFZnAs: A new candidate of host material of diluted magnetic semiconductors

    International Nuclear Information System (INIS)

    Chen Bi-Juan; Deng Zheng; Wang Xian-Cheng; Feng Shao-Min; Yuan Zhen; Zhang Si-Jia; Liu Qing-Qing; Jin Chang-Qing

    2016-01-01

    The layered semiconductor BaFZnAs with the tetragonal ZrCuSiAs-type structure has been successfully synthesized. Both the in-situ high-pressure synchrotron x-ray diffraction and the high-pressure Raman scattering measurements demonstrate that the structure of BaFZnAs is stable under pressure up to 17.5 GPa at room temperature. The resistivity and the magnetic susceptibility data show that BaFZnAs is a non-magnetic semiconductor. BaFZnAs is recommended as a candidate of the host material of diluted magnetic semiconductor. (special topic)

  4. Temperature and Pressure Evolution during Al Alloy Solidification at Different Squeeze Pressures

    International Nuclear Information System (INIS)

    Li, Junwen; Zhao, Haidong; Chen, Zhenming

    2015-01-01

    Squeeze casting is an advanced and near net-shape casting process, in which external high pressure is applied to solidifying castings. The castings are characterized with fine grains and good mechanical properties. In this study, a series of experiments were carried out to measure the temperature and pressure histories in cavity of Al-Si-Mg direct squeeze castings with different applied solidification pressures of 0.1, 50, 75, and 100 MPa. The evolution of the measured temperatures and pressures was compared and discussed. The effect of pressure change on formation of shrinkage defects was analyzed. Further the friction between the castings and dies during solidification was calculated. It is shown that the applied squeeze pressure has significant influence on the friction at die and casting interfaces, which affects the pressure evolution and transmission. The results could provide some benchmark data for future thermal-mechanics coupled modeling of squeeze castings. (paper)

  5. High pressure study of viscosity and temperature effects on tetracyanobenzene EDA complexes

    Science.gov (United States)

    Thomas, Michele Moisio; Drickamer, H. G.

    1981-12-01

    High pressure fluorescence studies from 0-10 kbar have been performed on electron donor-acceptor (EDA) complexes of s-tetracyanobenzene (TCNB) with a series of aromatic hydrocarbons. Four solvents were used: 2,2,4,4,6,8,8-heptamethylnonane (HMN), methylcyclohexane (MCH), 2,6,10,14-tetramethylpentadecane (TMPD), and a mixture of MCH and HMN. A viscosity range from 0.006 to 10 000 P was covered at two temperatures: 0 and 25 °C. As pressure (viscosity) increased the fluorescence spectrum shifted from one dominated by emission from the equilibrium (EQ) excited singlet state to one dominated by Franck-Condon (FC) singlet emission. Lifetime measurements for the complexes of o-xylene and p-xylene with TCNB yielded the two radiative rates (kEQ and kFC) as well as the rate of relaxation from FC to the EQ excited state (kRE). kRE was found to correlate well with viscosity and to be independent of temperature at constant viscosity, indicating that the relaxation process is diffusion controlled.

  6. Cell formation effects on the burning speeds and flame front area of synthetic gas at high pressures and temperatures

    International Nuclear Information System (INIS)

    Askari, Omid; Elia, Mimmo; Ferrari, Matthew; Metghalchi, Hameed

    2017-01-01

    Highlights: • Effect of cell formation on burning speed and flame surface area is investigated. • A new developed non-dimensional number called cellularity factor is introduced. • Cellular burning speed and mass burning rate are calculated using differential based multi-shell model. • Flame instability is studied using thermo-diffusive and hydrodynamics effects. • Power law correlations are developed for cellular burning speeds and mass burning rates. - Abstract: Cellular burning speeds and mass burning rates of premixed syngas/oxidizer/diluent (H_2/CO/O_2/He) have been determined at high pressures and temperatures over a wide range of equivalence ratios which are at engine-relevant conditions. Working on high pressure combustion helps to reduce the pollution and increase the energy efficiency in combustion devices. The experimental facilities consisted of two spherical and cylindrical chambers. The spherical chamber, which can withstand high pressures up to 400 atm, was used to collect pressure rise data due to combustion, to calculate cellular burning speed and mass burning rate. For flame structure and instability analysis the cylindrical chamber was used to take pictures of propagating flame using a high speed CMOS camera and a schlieren photography system. A new differential based multi-shell model based on pressure rise data was used to determine the cellular burning speed and mass burning rate. In this paper, cellular burning speed and mass burning rate of H_2/CO/O_2/He mixture have been measured for a wide range of equivalence ratios from 0.6 to 2, temperatures from 400 to 750 K and pressures from 2 to 50 atm for three hydrogen concentrations of 5, 10 and 25% in the syngas. The power law correlations for cellular burning speed and mass burning rate were developed as a function of equivalence ratio, temperature and pressure. In this study a new developed parameter, called cellularity factor, which indicates the cell formation effect on flame

  7. In situ measurement of magnesium carbonate formation from CO2 using static high-pressure and -temperature 13C NMR.

    Science.gov (United States)

    Surface, J Andrew; Skemer, Philip; Hayes, Sophia E; Conradi, Mark S

    2013-01-02

    We explore a new in situ NMR spectroscopy method that possesses the ability to monitor the chemical evolution of supercritical CO(2) in relevant conditions for geological CO(2) sequestration. As a model, we use the fast reaction of the mineral brucite, Mg(OH)(2), with supercritical CO(2) (88 bar) in aqueous conditions at 80 °C. The in situ conversion of CO(2) into metastable and stable carbonates is observed throughout the reaction. After more than 58 h of reaction, the sample was depressurized and analyzed using in situ Raman spectroscopy, where the laser was focused on the undisturbed products through the glass reaction tube. Postreaction, ex situ analysis was performed on the extracted and dried products using Raman spectroscopy, powder X-ray diffraction, and magic-angle spinning (1)H-decoupled (13)C NMR. These separate methods of analysis confirmed a spatial dependence of products, possibly caused by a gradient of reactant availability, pH, and/or a reaction mechanism that involves first forming hydroxy-hydrated (basic, hydrated) carbonates that convert to the end-product, anhydrous magnesite. This carbonation reaction illustrates the importance of static (unmixed) reaction systems at sequestration-like conditions.

  8. 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.

  9. Exchange of Na+ and K+ between water vapor and feldspar phases at high temperature and low vapor pressure

    Science.gov (United States)

    Fournier, R.O.

    1976-01-01

    In order to determine whether gas (steam) containing a small amount of dissolved alkali chloride is effective in promoting base exchange of Na+ and K+ among alkali feldspars and coexisting brine or brine plus solid salt, experiments were carried out at 400-700??C and steam densities ranging down to less than 0.05. For bulk compositions rich in potassium, the low pressure results are close to previous high-pressure results in composition of the fluid and coexisting solid phase. However, when the bulk composition is more sodic, alkali feldspars are relatively richer in potassium at low pressure than at high pressure. This behaviour corresponds to enrichment of potassium in the gas phase relative to coexisting brine and precipitation of solid NaCl when the brine plus gas composition becomes moderately sodic. The gas phase is very effective in promoting base exchange between coexisting alkali feldspars at high temperature and low water pressure. This suggests that those igneous rocks which contain coexisting alkali feldspars out of chemical equilibrium either remained very dry during the high-temperature part of their cooling history or that the pore fluid was a gas containing very little potassium relative to sodium. ?? 1976.

  10. Optimization of High Temperature and Pressurized Steam Modified Wood Fibers for High-Density Polyethylene Matrix Composites Using the Orthogonal Design Method

    Directory of Open Access Journals (Sweden)

    Xun Gao

    2016-10-01

    Full Text Available The orthogonal design method was used to determine the optimum conditions for modifying poplar fibers through a high temperature and pressurized steam treatment for the subsequent preparation of wood fiber/high-density polyethylene (HDPE composites. The extreme difference, variance, and significance analyses were performed to reveal the effect of the modification parameters on the mechanical properties of the prepared composites, and they yielded consistent results. The main findings indicated that the modification temperature most strongly affected the mechanical properties of the prepared composites, followed by the steam pressure. A temperature of 170 °C, a steam pressure of 0.8 MPa, and a processing time of 20 min were determined as the optimum parameters for fiber modification. Compared to the composites prepared from untreated fibers, the tensile, flexural, and impact strength of the composites prepared from modified fibers increased by 20.17%, 18.5%, and 19.3%, respectively. The effect on the properties of the composites was also investigated by scanning electron microscopy and dynamic mechanical analysis. When the temperature, steam pressure, and processing time reached the highest values, the composites exhibited the best mechanical properties, which were also well in agreement with the results of the extreme difference, variance, and significance analyses. Moreover, the crystallinity and thermal stability of the fibers and the storage modulus of the prepared composites improved; however, the hollocellulose content and the pH of the wood fibers decreased.

  11. Effect of chemical composition on the electrical conductivity of gneiss at high temperatures and pressures

    Directory of Open Access Journals (Sweden)

    L. Dai

    2018-03-01

    Full Text Available The electrical conductivity of gneiss samples with different chemical compositions (WA = Na2O + K2O + CaO  =  7.12, 7.27 and 7.64 % weight percent was measured using a complex impedance spectroscopic technique at 623–1073 K and 1.5 GPa and a frequency range of 10−1 to 106 Hz. Simultaneously, a pressure effect on the electrical conductivity was also determined for the WA = 7.12 % gneiss. The results indicated that the gneiss conductivities markedly increase with total alkali and calcium ion content. The sample conductivity and temperature conform to an Arrhenius relationship within a certain temperature range. The influence of pressure on gneiss conductivity is weaker than temperature, although conductivity still increases with pressure. According to various ranges of activation enthalpy (0.35–0.52 and 0.76–0.87 eV at 1.5 GPa, two main conduction mechanisms are suggested that dominate the electrical conductivity of gneiss: impurity conduction in the lower-temperature region and ionic conduction (charge carriers are K+, Na+ and Ca2+ in the higher-temperature region. The electrical conductivity of gneiss with various chemical compositions cannot be used to interpret the high conductivity anomalies in the Dabie–Sulu ultrahigh-pressure metamorphic belt. However, the conductivity–depth profiles for gneiss may provide an important constraint on the interpretation of field magnetotelluric conductivity results in the regional metamorphic belt.

  12. Nitrogen aggregation in Ib type synthetic diamonds at low pressure and high-temperature annealing

    International Nuclear Information System (INIS)

    Kazyuchits, N.M.; Rusetskij, M.S.; Latushko, Ya.I.; Kazyuchits, V.N.; Zajtsev, A.M.

    2015-01-01

    A new technique for annealing of diamonds at low pressure and high temperature (LPHT) is considered. The absorption spectra of synthetic Ib diamonds are given before and after annealing. This is evident from a comparison of the spectra that nitrogen aggregation process takes place at the LPHT annealing diamond. (authors)

  13. 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

  14. Small-angle x-ray scattering and density measurements of liquid Se50-Te50 mixture at high temperatures and high pressures using synchrotron radiation

    International Nuclear Information System (INIS)

    Kajihara, Y; Inui, M; Matsuda, K; Tomioka, Y

    2010-01-01

    We have carried out small-angle x-ray scattering and x-ray transmission measurements of liquid Se 50 -Te 50 mixture at SPring-8 in Japan and obtained the structure factor S(Q) at small-Q region (0.6 -1 ) and the density at high temperatures and high pressures up to 1000 0 C and 180 MPa. We report preliminary results in this paper. With increasing temperature, the density shows a minimum at around 500 0 C and a maximum at around 700 0 C. On the other hand, S(0) becomes maximum and S(Q) strongly depends on Q at around 600 0 C, which is about the middle temperature where the density shows the minimum and maximum. The temperatures shift to lower side when the pressure increases. These results prove that, with increasing temperature, the sample exhibits gradual transition from low-density structure to high-density structure, which causes mesoscopic density fluctuations in the intermediate temperature region.

  15. An in situ synchrotron energy-dispersive diffraction study of the hydration of oilwell cement systems under high temperature/autoclave conditions up to 130 deg. C

    International Nuclear Information System (INIS)

    Colston, Sally L.; Barnes, Paul; Jupe, Andrew C.; Jacques, Simon D.M.; Hall, Christopher; Livesey, Paul; Dransfield, John; Meller, Nicola; Maitland, Geoffrey C.

    2005-01-01

    The technique of synchrotron energy dispersive diffraction has been developed for in situ studies of cement hydration under autoclave conditions. This has been applied to oilwell cements hydrating at typical oilwell temperatures up to 130 deg. C. The results show clearly the detailed interplay between 11 detectable phases, from which a phase transformation scheme has been derived; this illustrates the progression of hydration up to 130 deg. C for two extreme cases, with and without conservation of water content and autoclave pressure. The monosulphate hydrate phases are found to exhibit different stability bounds, with a surprising sequence of the 14-water, 10-water then 12-water monosulphate as temperature/time increases; the latter form is particularly associated with conditions of water/pressure loss. The effect of retarders on C 3 S dissolution and CH formation is negligible above 70 deg. C, whereas the effect on the calcium sulphoaluminate hydrates is more complex, and possible reasons for this are discussed

  16. Microstructures define melting of molybdenum at high pressures

    Science.gov (United States)

    Hrubiak, Rostislav; Meng, Yue; Shen, Guoyin

    2017-03-01

    High-pressure melting anchors the phase diagram of a material, revealing the effect of pressure on the breakdown of the ordering of atoms in the solid. An important case is molybdenum, which has long been speculated to undergo an exceptionally steep increase in melting temperature when compressed. On the other hand, previous experiments showed nearly constant melting temperature as a function of pressure, in large discrepancy with theoretical expectations. Here we report a high-slope melting curve in molybdenum by synchrotron X-ray diffraction analysis of crystalline microstructures, generated by heating and subsequently rapidly quenching samples in a laser-heated diamond anvil cell. Distinct microstructural changes, observed at pressures up to 130 gigapascals, appear exclusively after melting, thus offering a reliable melting criterion. In addition, our study reveals a previously unsuspected transition in molybdenum at high pressure and high temperature, which yields highly textured body-centred cubic nanograins above a transition temperature.

  17. 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

  18. Solubilities of iron and nickel oxides under high temperature and high pressure conditions

    International Nuclear Information System (INIS)

    Choi, Ke-Chon; Jung, Yong-Ju; Yeon, Jei-Won; Jee, Kwang-Yong

    2007-01-01

    The purposes of primary coolant chemistry are to assure fuel and material integrity and to minimize out of core radiation fields. During the PWR operation, crud deposits are expected on the cladding, leading to cladding failure and raising the radioactivity. Such deposits come from the corrosion products of system surface. To achieve optimal conditions for primary coolant, basic researches on mass transfer, deposition and solubility of corrosion products are needed. The initial stage of crud formation could be the studies on the solubility of a structural material. It has been known that the solubility of metal oxides in boric acid under high temperature and high pressure condition depends on the pH and dissolved hydrogen. Thus, the effect of various pH on the solubility of metal oxide in boric acid solution was investigated in this work

  19. First-principles investigation of elastic anomalies in niobium at high pressure and temperature

    Science.gov (United States)

    Wang, Yi X.; Geng, Hua Y.; Wu, Q.; Chen, Xiang R.; Sun, Y.

    2017-12-01

    Niobium does not show any structure transition up to very high pressures. Nonetheless, by using density functional theory, we demonstrate in this work that it exhibits striking softening in elastic moduli C44 and C' at a pressure from 20 to 150 GPa. A novel anomaly softening in C44 from 275 to 400 GPa is also predicted. The physics behind these two anomalies is elaborated by electronic structure calculations, which revealed that they are actually different—first one directly relates to an underlying rhombohedral distortion whereas the latter originates in an electronic topological transition. The large magnitude of the softening leads to a remarkable elastic anisotropy in both the shear and the Young's moduli of Nb. Further investigation shows that thermo-electrons have an important role in these anomalies. This effect has not been noticed before. With increased electronic temperature, it is found that all anomalies (both the elastic softening and anisotropy) in Nb are gradually diminished, effectively giving rise to a temperature-induced hardening phenomenon.

  20. Integrated pressure and temperature sensor with high immunity against external disturbance for flexible endoscope operation

    Science.gov (United States)

    Maeda, Yusaku; Maeda, Kohei; Kobara, Hideki; Mori, Hirohito; Takao, Hidekuni

    2017-04-01

    In this study, an integrated pressure and temperature sensor device for a flexible endoscope with long-term stability in in vivo environments was developed and demonstrated. The sensor, which is embedded in the thin wall of the disposable endoscope hood, is intended for use in endoscopic surgery. The device surface is coated with a Cr layer to prevent photoelectronic generation induced by the strong light of the endoscope. The integrated temperature sensor allows compensation for the effect of the temperature drift on a pressure signal. The fabricated device pressure resolution is 0.4 mmHg; the corresponding pressure error is 3.2 mmHg. The packaged device was used in a surgical simulation in an animal experiment. Pressure and temperature monitoring was achieved even in a pH 1 acid solution. The device enables intraluminal pressure and temperature measurements of the stomach, which facilitate the maintenance of internal stomach conditions. The applicability of the sensor was successfully demonstrated in animal experiments.

  1. Robust high pressure stability and negative thermal expansion in sodium-rich antiperovskites Na3OBr and Na4OI2

    International Nuclear Information System (INIS)

    Wang, Yonggang; Wen, Ting; Park, Changyong; Kenney-Benson, Curtis; Pravica, Michael; Zhao, Yusheng; Yang, Wenge

    2016-01-01

    The structure stability under high pressure and thermal expansion behavior of Na 3 OBr and Na 4 OI 2 , two prototypes of alkali-metal-rich antiperovskites, were investigated by in situ synchrotron X-ray diffraction techniques under high pressure and low temperature. Both are soft materials with bulk modulus of 58.6 GPa and 52.0 GPa for Na 3 OBr and Na 4 OI 2 , respectively. The cubic Na 3 OBr structure and tetragonal Na 4 OI 2 with intergrowth K 2 NiF 4 structure are stable under high pressure up to 23 GPa. Although being a characteristic layered structure, Na 4 OI 2 exhibits nearly isotropic compressibility. Negative thermal expansion was observed at low temperature range (20–80 K) in both transition-metal-free antiperovskites for the first time. The robust high pressure structure stability was examined and confirmed by first-principles calculations among various possible polymorphisms qualitatively. The results provide in-depth understanding of the negative thermal expansion and robust crystal structure stability of these antiperovskite systems and their potential applications

  2. High pressure low temperature hot pressing method for producing a zirconium carbide ceramic

    Science.gov (United States)

    Cockeram, Brian V.

    2017-01-10

    A method for producing monolithic Zirconium Carbide (ZrC) is described. The method includes raising a pressure applied to a ZrC powder until a final pressure of greater than 40 MPa is reached; and raising a temperature of the ZrC powder until a final temperature of less than 2200.degree. C. is reached.

  3. Temperature and Pressure Effects on Drilling Fluid Rheology and ECD in Very Deep Wells

    Energy Technology Data Exchange (ETDEWEB)

    Rommetveit, R.; Bjoerkvoll, K.S.

    1997-12-31

    The rheological properties of drilling fluids are usually approximated to be independent of pressure and temperature. In many cases this is a good approximation. However, for wells with small margins between pore and fracture pressure, careful evaluations and analysis of the effects of temperature and pressure on well bore hydraulics and kick probability are needed. In this publication the effects of pressure and temperature are discussed and described for typical HPHT (High Pressure High Temperature) wells. Laboratory measurements show that rheology is very pressure and temperature dependent. The practical implications of these observations are illustrated through a series of calculations with an advanced pressure and temperature simulator. 10 refs., 15 figs.

  4. A novel fabrication technology of in situ TiB2/6063Al composites: High energy ball milling and melt in situ reaction

    International Nuclear Information System (INIS)

    Zhang, S.-L.; Yang, J.; Zhang, B.-R.; Zhao, Y.-T.; Chen, G.; Shi, X.-X.; Liang, Z.-P.

    2015-01-01

    Highlights: • This paper presents a novel technology to fabricate the TiB 2 /6063Al composites. • The novel technology decreases in situ reaction temperature and shortens the time. • The reaction mechanism of in situ reaction at the low temperature is discussed. • Effect of ball milling time and in situ reaction time on the composites is studied. - Abstract: TiB 2 /6063Al matrix composites are fabricated from Al–TiO 2 –B 2 O 3 system by the technology combining high energy ball milling with melt in situ reaction. The microstructure and tensile properties of the composites are investigated by XRD, SEM, EDS, TEM and electronic tensile testing. The results indicate that high energy ball milling technology decreases the in situ reaction temperature and shortens the reaction time for Al–TiO 2 –B 2 O 3 system in contrast with the conventional melt in situ synthesis. The morphology of in situ TiB 2 particles is exhibited in irregular shape or nearly circular shape, and the average size of the particles is less than 700 nm, thereinto the minimum size is approximately 200 nm. In addition, the morphology and size of the reinforced particles are affected by the time of ball milling and in situ reaction. TEM images indicate that the interface between 6063Al matrix and TiB 2 particles is clear and no interfacial outgrowth is observed. Tensile testing results show that the as-cast TiB 2 /6063Al composites exhibit a much higher strength, reaching 191 MPa, which is 1.23 times as high as the as-cast 6063Al matrix. Besides, the tensile fracture surface of the composites displays the dimple-fracture character

  5. High-Temperature Piezoelectric Sensing

    Directory of Open Access Journals (Sweden)

    Xiaoning Jiang

    2013-12-01

    Full Text Available Piezoelectric sensing is of increasing interest for high-temperature applications in aerospace, automotive, power plants and material processing due to its low cost, compact sensor size and simple signal conditioning, in comparison with other high-temperature sensing techniques. This paper presented an overview of high-temperature piezoelectric sensing techniques. Firstly, different types of high-temperature piezoelectric single crystals, electrode materials, and their pros and cons are discussed. Secondly, recent work on high-temperature piezoelectric sensors including accelerometer, surface acoustic wave sensor, ultrasound transducer, acoustic emission sensor, gas sensor, and pressure sensor for temperatures up to 1,250 °C were reviewed. Finally, discussions of existing challenges and future work for high-temperature piezoelectric sensing are presented.

  6. InAlN high electron mobility transistor Ti/Al/Ni/Au Ohmic contact optimisation assisted by in-situ high temperature transmission electron microscopy

    International Nuclear Information System (INIS)

    Smith, M. D.; Parbrook, P. J.; O'Mahony, D.; Conroy, M.; Schmidt, M.

    2015-01-01

    This paper correlates the micro-structural and electrical characteristics associated with annealing of metallic multi-layers typically used in the formation of Ohmic contacts to InAlN high electron mobility transistors. The multi-layers comprised Ti/Al/Ni/Au and were annealed via rapid thermal processing at temperatures up to 925 °C with electrical current-voltage analysis establishing the onset of Ohmic (linear IV) behaviour at 750–800 °C. In-situ temperature dependent transmission electron microscopy established that metallic diffusion and inter-mixing were initiated near a temperature of 500 °C. Around 800 °C, inter-diffusion of the metal and semiconductor (nitride) was observed, correlating with the onset of Ohmic electrical behaviour. The sheet resistance associated with the InAlN/AlN/GaN interface is highly sensitive to the anneal temperature, with the range depending on the Ti layer thickness. The relationship between contact resistivity and measurement temperature follow that predicted by thermionic field emission for contacts annealed below 850 °C, but deviated above this due to excessive metal-semiconductor inter-diffusion

  7. Thermodynamics of aqueous association and ionization reactions at high temperatures and pressures

    International Nuclear Information System (INIS)

    Mesmer, R.E.; Marshall, W.L.; Palmer, D.A.; Simonson, J.M.; Holmes, H.F.

    1990-01-01

    Electrochemical and electrical conductance cells have been widely used at ORNL over the years to quantitatively determine equilibrium constants and their salt effects to 300 degree C (EMF) and 800 degree C (conductance) at the saturation pressure of water (EMF) and to 4000 bars (conductance). The most precise results to 300 degree C for a large number of weak acids and bases show very similar thermodynamic behavior, which will be discussed. Results for the ionization constants of water, NH 3 (aq), HCl(aq), and NaCl(aq), which extend well into the supercritical region, have been fitted in terms of a model with dependence on density and temperature. The entropy change is found to be the driving force for ion-association reactions and this tendency increases (as it must) with increasing temperature at a given pressure. Also, the variation of all thermodynamic properties is greatly reduced at high fixed densities. Considerable variation occurs at low densities. From this analysis, the dependence of the reaction thermodynamics on the P-V-T properties of the solvent is shown, and the implication of large changes in hydration for solutes in the vicinity of the critical temperature will be discussed. Finally, the change in the molar compressibility coefficient for all reactions in water is shown to be the same and dependent only on the compressibility of the solvent

  8. The elastic solid solution model for minerals at high pressures and temperatures

    Science.gov (United States)

    Myhill, R.

    2018-02-01

    Non-ideality in mineral solid solutions affects their elastic and thermodynamic properties, their thermobaric stability, and the equilibrium phase relations in multiphase assemblages. At a given composition and state of order, non-ideality in minerals is typically modelled via excesses in Gibbs free energy which are either constant or linear with respect to pressure and temperature. This approach has been extremely successful when modelling near-ideal solutions. However, when the lattice parameters of the solution endmembers differ significantly, extrapolations of thermodynamic properties to high pressures using these models may result in significant errors. In this paper, I investigate the effect of parameterising solution models in terms of the Helmholtz free energy, treating volume (or lattice parameters) rather than pressure as an independent variable. This approach has been previously applied to models of order-disorder, but the implications for the thermodynamics and elasticity of solid solutions have not been fully explored. Solid solution models based on the Helmholtz free energy are intuitive at a microscopic level, as they automatically include the energetic contribution from elastic deformation of the endmember lattices. A chemical contribution must also be included in such models, which arises from atomic exchange within the solution. Derivations are provided for the thermodynamic properties of n-endmember solutions. Examples of the use of the elastic model are presented for the alkali halides, pyroxene, garnet, and bridgmanite solid solutions. Elastic theory provides insights into the microscopic origins of non-ideality in a range of solutions, and can make accurate predictions of excess enthalpies, entropies, and volumes as a function of volume and temperature. In solutions where experimental data are sparse or contradictory, the Helmholtz free energy approach can be used to assess the magnitude of excess properties and their variation as a function

  9. Automated high-pressure titration system with in situ infrared spectroscopic detection

    Energy Technology Data Exchange (ETDEWEB)

    Thompson, Christopher J., E-mail: chris.thompson@pnnl.gov; Martin, Paul F.; Chen, Jeffrey; Schaef, Herbert T.; Rosso, Kevin M.; Felmy, Andrew R.; Loring, John S. [Pacific Northwest National Laboratory, Richland, Washington 99352 (United States); Benezeth, Pascale [Géosciences Environnement Toulouse (GET), CNRS-Université de Toulouse, 31400 Toulouse (France)

    2014-04-15

    A fully automated titration system with infrared detection was developed for investigating interfacial chemistry at high pressures. The apparatus consists of a high-pressure fluid generation and delivery system coupled to a high-pressure cell with infrared optics. A manifold of electronically actuated valves is used to direct pressurized fluids into the cell. Precise reagent additions to the pressurized cell are made with calibrated tubing loops that are filled with reagent and placed in-line with the cell and a syringe pump. The cell's infrared optics facilitate both transmission and attenuated total reflection (ATR) measurements to monitor bulk-fluid composition and solid-surface phenomena such as adsorption, desorption, complexation, dissolution, and precipitation. Switching between the two measurement modes is accomplished with moveable mirrors that direct the light path of a Fourier transform infrared spectrometer into the cell along transmission or ATR light paths. The versatility of the high-pressure IR titration system was demonstrated with three case studies. First, we titrated water into supercritical CO{sub 2} (scCO{sub 2}) to generate an infrared calibration curve and determine the solubility of water in CO{sub 2} at 50 °C and 90 bar. Next, we characterized the partitioning of water between a montmorillonite clay and scCO{sub 2} at 50 °C and 90 bar. Transmission-mode spectra were used to quantify changes in the clay's sorbed water concentration as a function of scCO{sub 2} hydration, and ATR measurements provided insights into competitive residency of water and CO{sub 2} on the clay surface and in the interlayer. Finally, we demonstrated how time-dependent studies can be conducted with the system by monitoring the carbonation reaction of forsterite (Mg{sub 2}SiO{sub 4}) in water-bearing scCO{sub 2} at 50 °C and 90 bar. Immediately after water dissolved in the scCO{sub 2}, a thin film of adsorbed water formed on the mineral surface

  10. Automated high-pressure titration system with in situ infrared spectroscopic detection

    International Nuclear Information System (INIS)

    Thompson, Christopher J.; Martin, Paul F.; Chen, Jeffrey; Schaef, Herbert T.; Rosso, Kevin M.; Felmy, Andrew R.; Loring, John S.; Benezeth, Pascale

    2014-01-01

    A fully automated titration system with infrared detection was developed for investigating interfacial chemistry at high pressures. The apparatus consists of a high-pressure fluid generation and delivery system coupled to a high-pressure cell with infrared optics. A manifold of electronically actuated valves is used to direct pressurized fluids into the cell. Precise reagent additions to the pressurized cell are made with calibrated tubing loops that are filled with reagent and placed in-line with the cell and a syringe pump. The cell's infrared optics facilitate both transmission and attenuated total reflection (ATR) measurements to monitor bulk-fluid composition and solid-surface phenomena such as adsorption, desorption, complexation, dissolution, and precipitation. Switching between the two measurement modes is accomplished with moveable mirrors that direct the light path of a Fourier transform infrared spectrometer into the cell along transmission or ATR light paths. The versatility of the high-pressure IR titration system was demonstrated with three case studies. First, we titrated water into supercritical CO 2 (scCO 2 ) to generate an infrared calibration curve and determine the solubility of water in CO 2 at 50 °C and 90 bar. Next, we characterized the partitioning of water between a montmorillonite clay and scCO 2 at 50 °C and 90 bar. Transmission-mode spectra were used to quantify changes in the clay's sorbed water concentration as a function of scCO 2 hydration, and ATR measurements provided insights into competitive residency of water and CO 2 on the clay surface and in the interlayer. Finally, we demonstrated how time-dependent studies can be conducted with the system by monitoring the carbonation reaction of forsterite (Mg 2 SiO 4 ) in water-bearing scCO 2 at 50 °C and 90 bar. Immediately after water dissolved in the scCO 2 , a thin film of adsorbed water formed on the mineral surface, and the film thickness increased with time as the

  11. Effects of high hydrostatic pressure and temperature increase on Escherichia coli spp. and pectin methyl esterase inactivation in orange juice.

    Science.gov (United States)

    Torres, E F; González-M, G; Klotz, B; Rodrigo, D

    2016-03-01

    The aim of this study was to evaluate the effect of high hydrostatic pressure treatment combined with moderate processing temperatures (25 ℃-50 ℃) on the inactivation of Escherichia coli O157: H7 (ATCC 700728), E. coli K12 (ATCC 23716), and pectin methyl esterase in orange juice, using pressures of 250 to 500 MPa with times ranging between 1 and 30 min. Loss of viability of E. coli O157:H7 increased significantly as pressure and treatment time increased, achieving a 6.5 log cycle reduction at 400 MPa for 3 min at 25 ℃ of treatment. With regard to the inactivation of pectin methyl esterase, the greatest reduction obtained was 90.05 ± 0.01% at 50 ℃ and 500 MPa of pressure for 15 min; therefore, the pectin methyl esterase enzyme was highly resistant to the treatments by high hydrostatic pressure. The results obtained in this study showed a synergistic effect between the high pressure and moderate temperatures in inactivating E. coli cells. © The Author(s) 2016.

  12. Ion filter for high temperature cleaning

    International Nuclear Information System (INIS)

    Kutomi, Yasuhiro; Nakamori, Masaharu.

    1994-01-01

    A porous ceramic pipe mainly comprising alumina is used as a base pipe, and then crud and radioactive ion adsorbing materials in high temperature and high pressure water mainly comprising a FeTiO 3 compound are flame-coated on the outer surface thereof to a film thickness of about 100 to 300μ m as an aimed value by an acetylene flame-coating method. The flame-coated FeTiO 3 layer is also porous, so that high temperature and high pressure water to be cleaned can pass through from the inside to the outside of the pipe. Cruds can be removed and radioactive ions can be adsorbed during passage. Since all the operations can be conducted at high temperature and high pressure state, cooling is no more necessary for the high temperature and high pressure water to be cleaned, heat efficiency of the plant can be improved and a cooling facility can be saved. Further, since the flame-coating of FeTiO 3 to the porous ceramic pipe can be conducted extremely easily compared with production of a sintering product, cost for the production of filter elements can be saved remarkably. (T.M.)

  13. Borehole Stability in High-Temperature Formations

    Science.gov (United States)

    Yan, Chuanliang; Deng, Jingen; Yu, Baohua; Li, Wenliang; Chen, Zijian; Hu, Lianbo; Li, Yang

    2014-11-01

    In oil and gas drilling or geothermal well drilling, the temperature difference between the drilling fluid and formation will lead to an apparent temperature change around the borehole, which will influence the stress state around the borehole and tend to cause borehole instability in high geothermal gradient formations. The thermal effect is usually not considered as a factor in most of the conventional borehole stability models. In this research, in order to solve the borehole instability in high-temperature formations, a calculation model of the temperature field around the borehole during drilling is established. The effects of drilling fluid circulation, drilling fluid density, and mud displacement on the temperature field are analyzed. Besides these effects, the effect of temperature change on the stress around the borehole is analyzed based on thermoelasticity theory. In addition, the relationships between temperature and strength of four types of rocks are respectively established based on experimental results, and thermal expansion coefficients are also tested. On this basis, a borehole stability model is established considering thermal effects and the effect of temperature change on borehole stability is also analyzed. The results show that the fracture pressure and collapse pressure will both increase as the temperature of borehole rises, and vice versa. The fracture pressure is more sensitive to temperature. Temperature has different effects on collapse pressures due to different lithological characters; however, the variation of fracture pressure is unrelated to lithology. The research results can provide a reference for the design of drilling fluid density in high-temperature wells.

  14. Structural transformations in Ge{sub 2}Sb{sub 2}Te{sub 5} under high pressure and temperature

    Energy Technology Data Exchange (ETDEWEB)

    Mio, A. M.; Privitera, S., E-mail: stefania.privitera@imm.cnr.it; D' Arrigo, G.; Rimini, E. [IMM-CNR, Istituto per la Microelettronica e Microsistemi, Consiglio Nazionale delle Ricerche, Strada VIII 5, Zona Industriale, I-95121 Catania (Italy); Ceppatelli, M. [ICCOM-CNR, Istituto di Chimica dei Composti OrganoMetallici, Via Madonna del Piano 10, I-50019 Sesto Fiorentino (Italy); LENS, European Laboratory for Non-Linear Spectroscopy, Via Nello Carrara 1, I-50019 Sesto Fiorentino (Italy); Gorelli, F.; Santoro, M. [LENS, European Laboratory for Non-Linear Spectroscopy, Via Nello Carrara 1, I-50019 Sesto Fiorentino (Italy); INO-CNR, Istituto Nazionale di Ottica, Via Nello Carrara 1, I-50019 Sesto Fiorentino (Italy); Miritello, M. [MATIS-IMM-CNR, via S. Sofia 64, I-95123 Catania (Italy); Bini, R. [LENS, European Laboratory for Non-Linear Spectroscopy, Via Nello Carrara 1, I-50019 Sesto Fiorentino (Italy); Università degli Studi di Firenze, Via della Lastruccia 3, I-50019 Sesto Fiorentino (Italy)

    2015-08-14

    The structural transformations occurring in Ge{sub 2}Sb{sub 2}Te{sub 5} films heated at temperature up to 400 °C, and under hydrostatic pressure up to 12 GPa, have been investigated through in-situ X ray diffraction measurements. The adopted experimental conditions are close to those experienced by the phase change material during the SET (crystallization)/RESET (amorphization) processes in a nonvolatile memory device. The compression enhances the thermal stability of the amorphous phase, which remains stable up to 180 °C at 8 GPa and to 230 °C at 12 GPa. The structure of the crystalline phases is also modified, with the formation of a CsCl-type structure instead of rock-salt and of a GeS-type structure at the temperature at which usually the trigonal stable phase is formed. Overall, the stability of the stable phase appears to be more affected by the compression. We argue that the presence of weak bonds associated to the van der Waals gaps is a determining factor for the observed reduced stability.

  15. Carbon nanotube temperature and pressure sensors

    Energy Technology Data Exchange (ETDEWEB)

    Ivanov, Ilia N.; Geohegan, David B.

    2017-09-12

    The present invention, in one embodiment, provides a method of measuring pressure or temperature using a sensor including a sensor element composed of a plurality of carbon nanotubes. In one example, the resistance of the plurality of carbon nanotubes is measured in response to the application of temperature or pressure. The changes in resistance are then recorded and correlated to temperature or pressure. In one embodiment, the present invention provides for independent measurement of pressure or temperature using the sensors disclosed herein.

  16. Carbon nanotube temperature and pressure sensors

    Science.gov (United States)

    Ivanov, Ilia N; Geohegan, David Bruce

    2013-10-29

    The present invention, in one embodiment, provides a method of measuring pressure or temperature using a sensor including a sensor element composed of a plurality of carbon nanotubes. In one example, the resistance of the plurality of carbon nanotubes is measured in response to the application of temperature or pressure. The changes in resistance are then recorded and correlated to temperature or pressure. In one embodiment, the present invention provides for independent measurement of pressure or temperature using the sensors disclosed herein.

  17. 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.

  18. Spin crossover and Mott—Hubbard transition under high pressure and high temperature in the low mantle of the Earth

    Science.gov (United States)

    Ovchinnikov, S. G.; Ovchinnikova, T. M.; Plotkin, V. V.; Dyad'kov, P. G.

    2015-11-01

    Effect of high pressure induced spin crossover on the magnetic, electronic and structural properties of the minerals forming the Earth's low mantle is discussed. The low temperature P, T phase diagram of ferropericlase has the quantum phase transition point Pc = 56 GPa at T = 0 confirmed recently by the synchrotron Mössbauer spectroscopy. The LDA+GTB calculated phase diagram describes the experimental data. Its extension to the high temperature resulted earlier in prediction of the metallic properties of the Earth's mantle at the depth 1400 km insulator transition and compare them with the experimental seismic and geomagnetic field data.

  19. Atmospheric pressure and temperature profiling using near IR differential absorption lidar

    Science.gov (United States)

    Korb, C. L.; Schwemmer, G. K.; Dombrowski, M.; Weng, C. Y.

    1983-01-01

    The present investigation is concerned with differential absorption lidar techniques for remotely measuring the atmospheric temperature and pressure profile, surface pressure, and cloud top pressure-height. The procedure used in determining the pressure is based on the conduction of high-resolution measurements of absorption in the wings of lines in the oxygen A band. Absorption with respect to these areas is highly pressure sensitive in connection with the mechanism of collisional line broadening. The method of temperature measurement utilizes a determination of the absorption at the center of a selected line in the oxygen A band which originates from a quantum state with high ground state energy.

  20. 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)

  1. In-situ study of the thermal properties of hydrate slurry by high pressure DSC

    Energy Technology Data Exchange (ETDEWEB)

    Sari, O.; Hu, J.; Brun, F.; Erbeau, N. [Institute of Thermal Engineering, University of Applied Sciences of Western Switzerland, Yverdon-les-Bains (Switzerland); Homsy, P. [Nestec, Vevey (Switzerland); Logel, J.-C. [Axima Refrigeration, Bischheim (France)

    2008-07-01

    Knowing the enthalpy of hydrate slurry is very essential for energy balance and industrial applications. No direct measurement processes had been developed in this field in the past time. A new experimental method with special device has been developed to carry out on-line measurement of the thermal properties for hydrate slurry under dynamic conditions. With this special device, it is possible to deliver the hydrate slurry to the high pressure DSC (Differential Scanning Calorimetry) directly from the production tank or pipes. Thermal data acquisition will be performed afterwards by DSC. The investigated conditions were at pressure of 30 bar and temperature of {approx}+7 {sup o}C. The dissociation enthalpy of CO{sub 2} hydrate slurry was about 54 kJ/kg, corresponding 10.8% of solid fraction. The on-line measurement results for CO{sub 2} hydrate slurry give a good tendency to apply this phase change slurry to the industrial refrigeration process. (author)

  2. Reaction OH + OH studied over the 298-834 K temperature and 1-100 bar pressure ranges.

    Science.gov (United States)

    Sangwan, Manuvesh; Chesnokov, Evgeni N; Krasnoperov, Lev N

    2012-06-21

    Self-reaction of hydroxyl radicals, OH + OH → H(2)O + O (1a) and OH + OH → H(2)O(2) (1b), was studied using pulsed laser photolysis coupled to transient UV-vis absorption spectroscopy over the 298-834 K temperature and 1-100 bar pressure ranges (bath gas He). A heatable high-pressure flow reactor was employed. Hydroxyl radicals were prepared using reaction of electronically excited oxygen atoms, O((1)D), produced in photolysis of N(2)O at 193 nm, with H(2)O. The temporal behavior of OH radicals was monitored via transient absorption of light from a dc discharge in H(2)O/Ar low-pressure resonance lamp at ca. 308 nm. The absolute intensity of the photolysis light was determined by accurate in situ actinometry based on the ozone formation in the presence of molecular oxygen. The results of this study combined with the literature data indicate that the rate constant of reaction 1a, associated with the pressure independent component, decreases with temperature within the temperature range 298-414 K and increases above 555 K. The pressure dependent rate constant for (1b) was parametrized using the Troe expression as k(1b,inf) = (2.4 ± 0.6) × 10(-11)(T/300)(-0.5) cm(3) molecule(-1) s(-1), k(1b,0) = [He] (9.0 ± 2.2) × 10(-31)(T/300)(-3.5±0.5) cm(3) molecule(-1) s(-1), F(c) = 0.37.

  3. 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.

  4. Raman Spectroscopy of Serpentine and Reaction Products at High Pressure Using a Diamond Anvil Cell

    Science.gov (United States)

    Burgess, K.; Zinin, P.; Odake, S.; Fryer, P.; Hellebrand, E.

    2012-12-01

    Serpentine is one of the most abundant hydrous phases in the altered subducting plate, and contributes a large portion of the water flux in subduction zones. Measuring and understanding the structural changes in serpentine with pressure aids our understanding of the processes ongoing in oceanic crust and subduction zones. We have conducted high-pressure/high-temperature experiments on serpentine and its dehydration reaction products using a diamond anvil cell. We used the multifunctional in-situ measurement system equipped with a Raman device and laser heating system at the University of Hawaii. Well-characterized natural serpentinite was used in the study. Pressure was determined using the shift of the fluorescence line of a ruby placed next to the sample. Raman spectra of serpentine were obtained at higher pressures than previously published, up to 15 GPa; the peak shift with pressure fits the model determined by Auzende et al. [2004] at lower pressures. Heating was done at several different pressures up to 20 GPa, and reaction products were identified using Raman. Micro-Raman techniques allow us to determine reaction progress and heterogeneity within natural samples containing olivine and serpentine. Auzende, A-L., I. Daniel, B. Reynard, C. Lemaire, F. Guyot (2004). High-pressure behavior of serpentine minerals: a Raman spectroscopic study. Phys. Chem. Minerals 31 269-277.

  5. A novel fabrication technology of in situ TiB{sub 2}/6063Al composites: High energy ball milling and melt in situ reaction

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, S.-L.; Yang, J. [School of Materials Science and Engineering, Jiangsu University, Zhenjiang, Jiangsu 212013 (China); Zhang, B.-R. [School of Mechanical Engineering, Qilu University of Technology, Jinan, Shandong 250022 (China); Zhao, Y.-T., E-mail: 278075525@qq.com [School of Materials Science and Engineering, Jiangsu University, Zhenjiang, Jiangsu 212013 (China); Chen, G.; Shi, X.-X.; Liang, Z.-P. [School of Materials Science and Engineering, Jiangsu University, Zhenjiang, Jiangsu 212013 (China)

    2015-08-05

    Highlights: • This paper presents a novel technology to fabricate the TiB{sub 2}/6063Al composites. • The novel technology decreases in situ reaction temperature and shortens the time. • The reaction mechanism of in situ reaction at the low temperature is discussed. • Effect of ball milling time and in situ reaction time on the composites is studied. - Abstract: TiB{sub 2}/6063Al matrix composites are fabricated from Al–TiO{sub 2}–B{sub 2}O{sub 3} system by the technology combining high energy ball milling with melt in situ reaction. The microstructure and tensile properties of the composites are investigated by XRD, SEM, EDS, TEM and electronic tensile testing. The results indicate that high energy ball milling technology decreases the in situ reaction temperature and shortens the reaction time for Al–TiO{sub 2}–B{sub 2}O{sub 3} system in contrast with the conventional melt in situ synthesis. The morphology of in situ TiB{sub 2} particles is exhibited in irregular shape or nearly circular shape, and the average size of the particles is less than 700 nm, thereinto the minimum size is approximately 200 nm. In addition, the morphology and size of the reinforced particles are affected by the time of ball milling and in situ reaction. TEM images indicate that the interface between 6063Al matrix and TiB{sub 2} particles is clear and no interfacial outgrowth is observed. Tensile testing results show that the as-cast TiB{sub 2}/6063Al composites exhibit a much higher strength, reaching 191 MPa, which is 1.23 times as high as the as-cast 6063Al matrix. Besides, the tensile fracture surface of the composites displays the dimple-fracture character.

  6. Space efficient opposed-anvil high-pressure cell and its application to optical and NMR measurements up to 9 GPa

    International Nuclear Information System (INIS)

    Kitagawa, Kentaro; Gotou, Hirotada; Yagi, Takehiko; Yamada, Atsushi; Matsumoto, Takehiko; Uwatoko, Yoshiya; Takigawa, Masashi

    2010-01-01

    We have developed a new type of opposed-anvil high pressure cell with substantially improved space efficiency. The clamp cell and the gasket are made of non-magnetic Ni-Cr-Al alloy. Non-magnetic tungsten carbide (NMWC) is used for the anvils. The assembled cell with the dimension φ29 mm x 41 mm is capable of generating pressure up to 9 GPa over a relatively large volume of 7 mm 3 . Our cell is particularly suitable for those experiments which require large sample space to achieve good signal-to-noise ratio, such as the nuclear magnetic resonance (NMR) experiment. Argon is used as the pressure transmitting medium to obtain good hydrostaticity. The pressure was calibrated in situ by measuring the fluorescence from ruby through a transparent moissanite (6H-SiC) window. We have measured the pressure and temperature dependences of the 63 Cu nuclear-quadrupole-resonance (NQR) frequency of Cu 2 O, the in-plane Knight shift of metallic tin, and the Knight shift of platinum. These quantities can be used as reliable manometers to determine the pressure values in situ during the NMR/NQR experiments up to 9 GPa. (author)

  7. High-purity aluminium creep under high hydrostatic pressure

    International Nuclear Information System (INIS)

    Zajtsev, V.I.; Lyafer, E.I.; Tokij, V.V.

    1977-01-01

    The effect of the hydrostatic pressure on the rate of steady-state creep of high-purity aluminium was investigated. It is shown that the hydrostatic pressure inhibits the creep. The activation volume of the creep is independent of the direction in the range of (4.7-6.2) kg/mm 2 and of the pressure in the range of (1-7.8000) atm. It is concluded that self-diffusion does not control the creep of high-purity aluminium at room temperature in the investigated stress and pressure range

  8. Influence of pressure and temperature on molar volume and retention properties of peptides in ultra-high pressure liquid chromatography.

    Science.gov (United States)

    Fekete, Szabolcs; Horváth, Krisztián; Guillarme, Davy

    2013-10-11

    In this study, pressure induced changes in retention were measured for model peptides possessing molecular weights between ∼1 and ∼4kDa. The goal of the present work was to evaluate if such changes were only attributed to the variation of molar volume and if they could be estimated prior to the experiments, using theoretical models. Restrictor tubing was employed to generate pressures up to 1000bar and experiments were conducted for mobile phase temperatures comprised between 30 and 80°C. As expected, the retention increases significantly with pressure, up to 200% for glucagon at around 1000bar compared to ∼100bar. The obtained data were fitted with a theoretical model and the determination coefficients were excellent (r(2)>0.9992) for the peptides at various temperatures. On the other hand, the pressure induced change in retention was found to be temperature dependent and was more pronounced at 30°C vs. 60 or 80°C. Finally, using the proposed model, it was possible to easily estimate the pressure induced increase in retention for any peptide and mobile phase temperature. This allows to easily estimating the expected change in retention, when increasing the column length under UHPLC conditions. Copyright © 2013 Elsevier B.V. All rights reserved.

  9. High-temperature superconducting phase of HBr under pressure predicted by first-principles calculations

    Science.gov (United States)

    Gu, Qinyan; Lu, Pengchao; Xia, Kang; Sun, Jian; Xing, Dingyu

    2017-08-01

    The high pressure phases of HBr are explored with an ab initio crystal structure search. By taking into account the contribution of zero-point energy (ZPE), we find that the P 4 /n m m phase of HBr is thermodynamically stable in the pressure range from 150 to 200 GPa. The superconducting critical temperature (Tc) of P 4 /n m m HBr is evaluated to be around 73 K at 170 GPa, which is the highest record so far among binary halogen hydrides. Its Tc can be further raised to around 95K under 170 GPa if half of the bromine atoms in the P 4 /n m m HBr are substituted by the lighter chlorine atoms. Our study shows that, in addition to lower mass, higher coordination number, shorter bonds, and more highly symmetric environment for the hydrogen atoms are important factors to enhance the superconductivity in hydrides.

  10. Gas erosion of impeller housing in the operation of a high-temperature, high-pressure helium circulator

    International Nuclear Information System (INIS)

    Sanders, J.P.; Heestand, R.L.; Young, H.C.

    1987-01-01

    Three gas-bearing circulators are installed in series in a high-pressure, high-temperature loop to provide helium flow up to 0.47 m 3 /s at a total head of 78 kJ/kg. The design pressure is 10.7 MPa, and temperatures of 1000 0 C can be obtained in the test section. The inlet temperature to the circulators is limited to 450 0 C. During a routine examination of the circulator, deep V-shaped grooves were found in the stationary surface of this cavity. At the same time, a very fine, dark particulate was observed in crevices of the housing. At first it was assumed that the grooves were formed by particulate erosion; however, examination of the grooves and discussions with persons experienced with large circulator operation changed this opinion. Erosion caused by particulate is characteristically rounded on the bottom and has a greater width to depth aspect than the V-shaped grooves, which were observed. Analysis of the particulate indicated that it was essentially the material of the housing that had undergone reactions with impurities in the circulating gas. It was subsequently concluded that the impeller housing had not been heat treated in a sufficiently oxidizing atmosphere after machining to form an adherent oxide coating. This suboxide coating was eroded by the shear forces in the gas. The exposed layer of metal was then further oxidized by the impurities in the gas, and these layers of oxide were successively eroded to produce the grooves. This erosion problem was eliminated by machining a ring of the same material, heat treating it to form an adherent stable oxide, and bolting it in place in the cavity

  11. Filter-based Aerosol Measurement Experiments using Spherical Aerosol Particles under High Temperature and High Pressure

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Jong Chan; Jung, Woo Young; Lee, Hyun Chul; Lee, Doo Young [FNC TECH., Yongin (Korea, Republic of)

    2016-05-15

    Optical Particle Counter (OPC) is used to provide real-time measurement of aerosol concentration and size distribution. Glass fiber membrane filter also be used to measure average mass concentration. Three tests (MTA-1, 2 and 3) have been conducted to study thermal-hydraulic effect, a filtering tendency at given SiO{sub 2} particles. Based on the experimental results, the experiment will be carried out further with a main carrier gas of steam and different aerosol size. The test results will provide representative behavior of the aerosols under various conditions. The aim of the tests, MTA 1, 2 and 3, are to be able to 1) establish the test manuals for aerosol generation, mixing, sampling and measurement system, which defines aerosol preparation, calibration, operating and evaluation method under high pressure and high temperature 2) develop commercial aerosol test modules applicable to the thermal power plant, environmental industry, automobile exhaust gas, chemical plant, HVAC system including nuclear power plant. Based on the test results, sampled aerosol particles in the filter indicate that important parameters affecting aerosol behavior aerosols are 1) system temperature to keep above a evaporation temperature of ethanol and 2) aerosol losses due to the settling by ethanol liquid droplet.

  12. Ultrafine grain formation in Mg–Zn alloy by in situ precipitation during high-pressure torsion

    International Nuclear Information System (INIS)

    Meng, Fanqiang; Rosalie, Julian M.; Singh, Alok; Somekawa, Hidetoshi; Tsuchiya, Koichi

    2014-01-01

    A ultrafine-grained structure was produced in a Mg–3.4Zn (at.%) alloy subjected to high-pressure torsion (HPT) at ambient temperature. Hardness and X-ray diffraction measurements indicated the microstructure reached a steady state after three revolutions. Transmission electron microscopy observations showed equiaxed, dynamically recrystallized grains with an average diameter of 140 nm after 20 revolutions, substantially less than the steady-state grain size in pure Mg deformed by HPT. This is attributed to the formation of precipitates during processing, which impedes the growth of recrystallized grains

  13. Sintering and characterization of SrBi_2Ta_2O_9 obtained by high-pressure processing at low temperatures

    International Nuclear Information System (INIS)

    Souza, Ricson R.; Kirchner, Rejane K.; Jurado, Jose R.; Pereira, Altair S.; Sousa, Vânia C.

    2016-01-01

    High-pressure processing is a very attractive approach for the production of materials with new and/or improved properties. In this work, pressures in the order of 7.7 GPa and 2.5 GPa were induced in SrBi_2Ta_2O_9 samples at different temperatures placed in a specific reaction cell and generated different effects on phase formation. The microstructural evolution during high-pressure processing was investigated by scanning electron microscopy in association with energy dispersion spectroscopy and with the support of an X-ray diffraction analyzer. Frequency response analysis was used to obtain the dielectric curves by electrochemical impedance spectroscopy. A SrBi_2Ta_2O_9 single-phase sample, treated at 2.5 GPa and 900 °C, was used to evaluate the electrical properties, obtaining a dielectric response similar to SrBi_2Ta_2O_9 samples sintered by conventional processes at temperatures above 1000 °C. In addition, by this method, it was possible to obtain ceramics with uniform microstructure and a relative density of 93%. - Highlights: • The first production of SrBi_2Ta_2O_9 using the technique of high-pressure processing. • The ability to produce single-phase SrBi_2Ta_2O_9 treated at 2.5 GPa and 900 °C. • The electrical properties are compatible with SBT sintered at high temperatures.

  14. Temperature-compensated pressure detectors and transmitter for use in hostile environment

    International Nuclear Information System (INIS)

    Di Noia, E.J.; Breunich, T.R.

    1984-01-01

    A pressure or differential pressure detector suitable for use in a hostile environment, for example, under high pressure, temperature, and radiation conditions in the containment vessel of a nuclear generating plant includes as a transducer a linear variable differential transformer (LVDT) disposed within a detector housing designed to withstand temperatures of about 260 deg C. A signal detecting and conditioning circuit remote from the detector housing includes a demodulator for producing X and Y demodulated signals respectively from A and B secondary windings of the LVDT, a summing circuit for producing a temperature analog voltage X + Y, a subtractor for providing a differential pressure analog voltage X - Y, and a multiplier for multiplying the differential pressure analog voltage X - Y by a temperature compensation voltage X + Y - Ref based on the temperature analog voltage to provide a resulting temperature-compensated differential pressure analog signal. (author)

  15. Adsorption Device Based on a Langatate Crystal Microbalance for High Temperature High Pressure Gas Adsorption in Zeolite H-ZSM-5.

    Science.gov (United States)

    Ding, Wenjin; Baracchini, Giulia; Klumpp, Michael; Schwieger, Wilhelm; Dittmeyer, Roland

    2016-08-25

    We present a high-temperature and high-pressure gas adsorption measurement device based on a high-frequency oscillating microbalance (5 MHz langatate crystal microbalance, LCM) and its use for gas adsorption measurements in zeolite H-ZSM-5. Prior to the adsorption measurements, zeolite H-ZSM-5 crystals were synthesized on the gold electrode in the center of the LCM, without covering the connection points of the gold electrodes to the oscillator, by the steam-assisted crystallization (SAC) method, so that the zeolite crystals remain attached to the oscillating microbalance while keeping good electroconductivity of the LCM during the adsorption measurements. Compared to a conventional quartz crystal microbalance (QCM) which is limited to temperatures below 80 °C, the LCM can realize the adsorption measurements in principle at temperatures as high as 200-300 °C (i.e., at or close to the reaction temperature of the target application of one-stage DME synthesis from the synthesis gas), owing to the absence of crystalline-phase transitions up to its melting point (1,470 °C). The system was applied to investigate the adsorption of CO2, H2O, methanol and dimethyl ether (DME), each in the gas phase, on zeolite H-ZSM-5 in the temperature and pressure range of 50-150 °C and 0-18 bar, respectively. The results showed that the adsorption isotherms of these gases in H-ZSM-5 can be well fitted by Langmuir-type adsorption isotherms. Furthermore, the determined adsorption parameters, i.e., adsorption capacities, adsorption enthalpies, and adsorption entropies, compare well to literature data. In this work, the results for CO2 are shown as an example.

  16. High temperature deformation behavior of gradually pressurized zircaloy-4 tubes

    International Nuclear Information System (INIS)

    Suzuki, Motoye

    1982-03-01

    In order to obtain preliminary perspectives on fuel cladding deformation behavior under changing temperature and pressure conditions in a hypothetical loss-of-coolant accident of PWR, a Zircaloy-4 tube burst test was conducted in both air and 99.97% Ar atomospheres. The tubes were directly heated by AC-current and maintained at various temperatures, and pressurized gradually until rupture occurred. Rupture circumferential strains were generally larger in Ar gas than in air and attained a maximum around 1100 K in both atmospheres. Some tube tested in air produced axially-extended long balloons, which proved not to be explained by such properties or ideas as effect of cooling on strain rate, superplasticity, geometrical plastic instability and stresses generated by surface oxide layer. A cause of the long balloon may be obtained in the anisotropy of the material structure. But even a qualitative analysis based on this property can not be made due to insufficient data of the anisotropy. (author)

  17. High pressure experimental water loop

    International Nuclear Information System (INIS)

    Grenon, M.

    1958-01-01

    A high pressure experimental water loop has been made for studying the detection and evolution of cladding failure in a pressurized reactor. The loop has been designed for a maximum temperature of 360 deg. C, a maximum of 160 kg/cm 2 and flow rates up to 5 m 3 /h. The entire loop consists of several parts: a main circuit with a canned rotor circulation pump, steam pressurizer, heating tubes, two hydro-cyclones (one de-gasser and one decanter) and one tubular heat exchanger; a continuous purification loop, connected in parallel, comprising pressure reducing valves and resin pots which also allow studies of the stability of resins under pressure, temperature and radiation; following the gas separator is a gas loop for studying the recombination of the radiolytic gases in the steam phase. The preceding circuits, as well as others, return to a low pressure storage circuit. The cold water of the low pressure storage flask is continuously reintroduced into the high pressure main circuit by means of a return pump at a maximum head of 160 kg /cm 2 , and adjusted to the pressurizer level. This loop is also a testing bench for the tight high pressure apparatus. The circulating pump and the connecting flanges (Oak Ridge type) are water-tight. The feed pump and the pressure reducing valves are not; the un-tight ones have a system of leak recovery. To permanently check the tightness the circuit has been fitted with a leak detection system (similar to the HRT one). (author) [fr

  18. Melting of KCl and pressure calibration from in situ ionic conductivity measurements in a multi-anvil apparatus

    Science.gov (United States)

    Li, J.; Dong, J.; Zhu, F.

    2017-12-01

    Melting plays an unparalleled role in planetary differentiation processes including the formation of metallic cores, basaltic crusts, and atmospheres. Knowledge of the melting behavior of Earth materials provides critical constraints for establishing the Earth's thermal structure, interpreting regional seismic anomalies, and understanding the nature of chemical heterogeneity. Measuring the melting points of compressed materials, however, have remained challenging mainly because melts are often mobile and reactive, and temperature and pressure gradients across millimeter or micron-sized samples introduce large uncertainties in melting detection. Here the melting curve of KCl was determined through in situ ionic conductivity measurements, using the multi-anvil apparatus at the University of Michigan. The method improves upon the symmetric configuration that was used recently for studying the melting behaviors of NaCl, Na2CO3, and CaCO3 (Li and Li 2015 American Mineralogist, Li et al. 2017 Earth and Planetary Science Letters). In the new configuration, the thermocouple and electrodes are placed together with the sample at the center of a cylindrical heater where the temperature is the highest along the axis, in order to minimize uncertainties in temperature measurements and increase the stability of the sample and electrodes. With 1% reproducibility in melting point determination at pressures up to 20 GPa, this method allows us to determine the sample pressure to oil load relationship at high temperatures during multiple heating and cooling cycles, on the basis of the well-known melting curves of ionic compounds. This approach enables more reliable pressure measurements than relying on a small number of fixed-point phase transitions. The new data on KCl bridge the gap between the piston-cylinder results up to 4 GPa (Pistorius 1965 J. of Physics and Chemistry of Solids) and several diamond-anvil cell data points above 20 GPa (Boehler et al. 1996 Physical Review). We

  19. Molecular Dynamics Simulations of Liquid Phosphorus at High Temperature and Pressure

    International Nuclear Information System (INIS)

    Wu Yanning; Zhao Gang; Liu Changsong; Zhu Zhengang

    2008-01-01

    By performing ab initio molecular dynamics simulations, we have investigated the microstructure, dynamical and electronic properties of liquid phosphorus (P) under high temperature and pressure. In our simulations, the calculated coordination number (CN) changes discontinuously with density, and seems to increase rapidly after liquid P is compressed to 2.5 g/cm 3 . Under compression, liquid P shows the first-order liquid-liquid phase transition from the molecular liquid composed of the tetrahedral P 4 molecules to complex polymeric form with three-dimensional network structure, accompanied by the nonmetal to metal transition of the electronic structure. The order parameters Q 6 and Q 4 are sensitive to the microstructural change of liquid P. By calculating diffusion coefficients, we show the dynamical anomaly of liquid P by compression. At lower temperatures, a maximum exists at the diffusion coefficients as a function of density; at higher temperatures, the anomalous behavior is weakened. The excess entropy shows the same phenomena as the diffusion coefficients. By analysis of the angle distribution functions and angular limited triplet correlation functions, we can clearly find that the Peierls distortion in polymeric form of liquid P is reduced by further compression

  20. Phase transitions in solids under high pressure

    CERN Document Server

    Blank, Vladimir Davydovich

    2013-01-01

    Phase equilibria and kinetics of phase transformations under high pressureEquipment and methods for the study of phase transformations in solids at high pressuresPhase transformations of carbon and boron nitride at high pressure and deformation under pressurePhase transitions in Si and Ge at high pressure and deformation under pressurePolymorphic α-ω transformation in titanium, zirconium and zirconium-titanium alloys Phase transformations in iron and its alloys at high pressure Phase transformations in gallium and ceriumOn the possible polymorphic transformations in transition metals under pressurePressure-induced polymorphic transformations in АIBVII compoundsPhase transformations in AIIBVI and AIIIBV semiconductor compoundsEffect of pressure on the kinetics of phase transformations in iron alloysTransformations during deformation at high pressure Effects due to phase transformations at high pressureKinetics and hysteresis in high-temperature polymorphic transformations under pressureHysteresis and kineti...

  1. High-Pressure Polymorphism in Orthoamphiboles

    Science.gov (United States)

    Finkelstein, G. J.; Zhang, D.; Shelton, H.; Dera, P.

    2017-12-01

    Amphiboles are double-chain silicate minerals that are the structurally hydrated counterpart to single-chain, anhydrous pyroxenes. They may play an important role in the earth as a carrier for volatiles in subduction zones, as well as a generator for seismic anisotropy in the upper mantle. Recent work has described previously unrecognized high-pressure polymorphism at low temperatures in a variety of pyroxene minerals, which may be relevant for the structure and dynamics of thick, cold, subducted slabs. However, high-pressure polymorphism in amphiboles above a few GPa in pressure has not been well explored, and if similar polymorphism to pyroxenes exists in this mineral family, it may affect the extent and depth of volatile transport in amphiboles, as well as their rheological properties. At low temperatures and high pressures, orthopyroxenes undergo crystal structure transitions at lower pressures than clinopyroxenes (10-30 GPa vs. > 50 GPa), so for this study we have investigated polymorphism in the anthophyllite-gedrite (Al-free and Al rich) orthoamphibole solid solution series. Using neon gas-loaded diamond anvil cells, we compressed both phases to a maximum pressure of 31 GPa, and observed transitions to new monoclinic structures in both endmembers. In this presentation, we will discuss the details of these transitions and implications for the earth's interior.

  2. Propargyl Recombination: Estimation of the High Temperature, Low Pressure Rate Constant from Flame Measurements

    DEFF Research Database (Denmark)

    Rasmussen, Christian Lund; Skjøth-Rasmussen, Martin Skov; Jensen, Anker

    2005-01-01

    The most important cyclization reaction in hydrocarbon flames is probably recombination of propargyl radicals. This reaction may, depending on reaction conditions, form benzene, phenyl or fulvene, as well as a range of linear products. A number of rate measurements have been reported for C3H3 + C3H......3 at temperatures below 1000 K, while data at high temperature and low pressure only can be obtained from flames. In the present work, an estimate of the rate constant for the reaction at 1400 +/- 50 K and 20 Torr is obtained from analysis of the fuel-rich acetylene flame of Westmoreland, Howard...

  3. Dynamic hyperfiltration membranes for high-temperature spacecraft wash water recycle

    Science.gov (United States)

    Gaddis, J. L.; Brandon, C. A.

    1978-01-01

    The effect of operating parameters on the performance of the hyperfiltration membrane when operating on washwater was examined. The parameters were pressure, temperature, velocity, and concentration. Data taken included rejections of organic materials, ammonia, urea, and an assortment of ions. The membrane used was a dual layer, polyacrylic acid over zirconium oxide, deposited in situ on a porcelain ceramic substrate.

  4. High-temperature deformation and rupture behavior of internally-pressurized Zircaloy-4 cladding in vacuum and steam enivronments

    International Nuclear Information System (INIS)

    Chung, H.M.; Garde, A.M.; Kassner, T.F.

    1977-01-01

    The high-temperature diametral expansion and rupture behavior of Zircaloy-4 fuel-cladding tubes have been investigated in vacuum and steam environments under transient-heating conditions that are of interest in hypothetical loss-of-coolant accident situations in light-water reactors. The effects of internal pressure, heating rate, axial constraint, and localized temperature nonuniformities in the cladding on the maximum circumferential strain have been determined for burst temperatures between approximately 650 and 1350 0 C

  5. Temperature and pressure dependent osmotic pressure in liquid sodium-cesium alloys

    International Nuclear Information System (INIS)

    Rashid, R.I.M.A.

    1987-01-01

    The evaluation of the osmotic pressure in terms of the concentration fluctuations of mixtures and the equations of state of the pure liquids is considered. The temperature and pressure dependent experimentally measured concentration-concentration correlations in the long wavelength limit of liquid sodium-cesium alloys are used to demonstrate the appreciable dependence of the temperature and pressure on the osmotic pressure as a function of concentration. Introducing interchange energies as functions of temperature and pressure, our analysis is consistent with the Flory model. Thus, a formalism for evaluating the state dependent osmotic pressure is developed and our numerical work is considered to be an extension of the calculations of Rashid and March in the sense that a temperature and pressure dependent interchange energy parameter that more closely parameterizes the state dependent concentration fluctuations in the liquid alloys, is used. (author)

  6. First-Principle Calculations for Thermodynamic Properties of LiBC Under High Temperature and High Pressure

    Institute of Scientific and Technical Information of China (English)

    LIU Zhong-Li; CHENG Yan; TAN Ni-Na; GOU Qing-Quan

    2006-01-01

    The thermodynamic properties of LiBC are investigated by using the full-potential linearized muffin-tin orbital method (FP-LMTO) within the frame of density functional theory (DFT) and using the quasi-harmonic Debye model. The dependencies of the normalized lattice parameters a/a0 and c/c0, the ratio (c/a)/2, the normalized primitive volume V/V0 on pressure and temperature are successfully obtained. It is found that the interlayer covalent interactions (Li-B bonds or Li-C bonds) are more sensitive to temperature and pressure than intralayer ones (B-C bonds), as gives rise to the extreme lattice anisotropy in the bulk hcp LiBC.

  7. Experimental study of the polyamorphism of water. II. The isobaric transitions between HDA and VHDA at intermediate and high pressures

    Science.gov (United States)

    Handle, Philip H.; Loerting, Thomas

    2018-03-01

    Since the first report of very-high density amorphous ice (VHDA) in 2001 [T. Loerting et al., Phys. Chem. Chem. Phys. 3, 5355-5357 (2001)], the status of VHDA as a distinct amorphous ice has been debated. We here study VHDA and its relation to expanded high density amorphous ice (eHDA) on the basis of isobaric heating experiments. VHDA was heated at 0.1 ≤ p ≤ 0.7 GPa, and eHDA was heated at 1.1 ≤ p ≤ 1.6 GPa to achieve interconversion. The behavior upon heating is monitored using in situ volumetry as well as ex situ X-ray diffraction and differential scanning calorimetry. We do not observe a sharp transition for any of the isobaric experiments. Instead, a continuous expansion (VHDA) or densification (eHDA) marks the interconversion. This suggests that a continuum of states exists between VHDA and HDA, at least in the temperature range studied here. This further suggests that VHDA is the most relaxed amorphous ice at high pressures and eHDA is the most relaxed amorphous ice at intermediate pressures. It remains unclear whether or not HDA and VHDA experience a sharp transition upon isothermal compression/decompression at low temperature.

  8. In-situ calibration of RTDs and pressure sensors in nuclear power plants

    International Nuclear Information System (INIS)

    Hashemian, H.M.

    1994-01-01

    New techniques have been developed and validated for in-situ calibration of pressure transmitters as installed in nuclear power plants. These new techniques originate from a desire within the nuclear industry to monitor the calibration of pressure sensors during normal power operation by monitoring the DC output of the sensors for any significant draft and other anomalies. Currently, the calibration of pressure sensors is performed once every fuel cycle (18-24 months). The work involves significant manpower, radiation exposure to plant personnel, and potential damage to the plant equipment. In-situ calibration offers the potential to identify the sensors that need to be replaced or require calibration during normal plant operation, and reduce the calibration effort during outages to those sensors that need to be calibrated, as opposed to calibrating all the sensors

  9. Development of an optical time-resolved measurement system under high-pressure and low-temperature with a piston-cylinder pressure cell

    Science.gov (United States)

    Tsuchiya, Satoshi; Kino, Yohei; Nakagawa, Koichi; Nakagawa, Daisuke; Yamada, Jun-ichi; Toda, Yasunori

    2016-04-01

    To perform the femtosecond pump-probe spectroscopy under high pressure and low temperature, we constructed a measurement system with a piston cylinder type pressure cell installing an optical fiber bundle. The applied pressure was achieved to 6 kbar and the cell was cooled down to 15 K. Several demonstrations revealed that broadening and change of polarization of pulse (duration of ˜120 fs) owing to the dispersions in the fiber bundle are much small indicating that those have little influence on the measurement of carrier relaxation dynamics. In the measurements of κ-(BEDT-TTF)2Cu(NCS)2 under 1.3 kbar at 43 K, we have successfully detected the polarization anisotropy of the carrier relaxation dynamics and estimated the decay time in the same way as the normal measurement.

  10. High pressure structural studies on nanophase praseodymium oxide

    International Nuclear Information System (INIS)

    Saranya, L.; Chandra Shekar, N.V.; Amirthapandian, S.; Hussain, Shamima; Arulraj, A.; Sahu, P. Ch.

    2014-01-01

    The phase stability of nanocrystalline Pr 2 O 3 has been investigated under pressure by in-situ high pressure X-ray diffraction using Mao-Bell type diamond anvil cell. The ambient structure and phase of the praseodymium oxide have been resolved unambiguously using x-ray diffraction, SEM and TEM techniques. Under the action of pressure the cubic phase of the system is retained up to 15 GPa. This is unusual as other isostructural rare earth oxides show structural transformations even at lower pressures. From the best fit to the P–V data with the Murnaghan equation of state yields a bulk modulus of 171 GPa

  11. High pressure structural studies on nanophase praseodymium oxide

    Energy Technology Data Exchange (ETDEWEB)

    Saranya, L. [Jamal Mohamed College, Tiruchirapalli 620020, Tamil Nadu (India); Chandra Shekar, N.V., E-mail: chandru@igcar.gov.in [Condensed Matter Physics Division, Materials Science Group, Indira Gandhi Centre for Atomic Research, Kalpakkam 603102, Tamil Nadu (India); Amirthapandian, S. [Materials Physics Division, Materials Science Group, Indira Gandhi Centre for Atomic Research, Kalpakkam 603102, Tamil Nadu (India); Hussain, Shamima [UGC-DAE-CSR node, Kokilamedu 603103, Tamil Nadu (India); Arulraj, A.; Sahu, P. Ch. [Condensed Matter Physics Division, Materials Science Group, Indira Gandhi Centre for Atomic Research, Kalpakkam 603102, Tamil Nadu (India)

    2014-09-15

    The phase stability of nanocrystalline Pr{sub 2}O{sub 3} has been investigated under pressure by in-situ high pressure X-ray diffraction using Mao-Bell type diamond anvil cell. The ambient structure and phase of the praseodymium oxide have been resolved unambiguously using x-ray diffraction, SEM and TEM techniques. Under the action of pressure the cubic phase of the system is retained up to 15 GPa. This is unusual as other isostructural rare earth oxides show structural transformations even at lower pressures. From the best fit to the P–V data with the Murnaghan equation of state yields a bulk modulus of 171 GPa.

  12. Progress in understanding the mechanical behavior of pressure-vessel materials at elevated temperatures

    International Nuclear Information System (INIS)

    Swindeman, R.W.; Brinkman, C.R.

    1981-01-01

    Progress during the 1970's on the production of high-temperature mechanical properties data for pressure vessel materials was reviewed. The direction of the research was toward satisfying new data requirements to implement advances in high-temperature inelastic design methods. To meet these needs, servo-controlled testing machines and high-resolution extensometry were developed to gain more information on the essential behavioral features of high-temperature alloys. The similarities and differences in the mechanical response of various pressure vessel materials were identified. High-temperature pressure vessel materials that have received the most attention included Type 304 stainless steel, Type 316 stainless steel, 2 1/4 Cr-1 Mo steel, alloy 800H, and Hastelloy X

  13. Fluid and rock interactions in silicate and aluminosilicate systems at elevated pressure and temperature

    Science.gov (United States)

    Davis, Mary Kathleen

    Understanding fluid chemistry in the subduction zone environment is key to unraveling the details of element transport from the slab to the surface. Solubilities of cations, such as silicon, in water strongly affect both the physical and chemical properties of supercritical metamorphic fluids. Modeling the thermodynamics of fluid-rock interactions requires therefore a profound understanding of cation dissolution and aqueous speciation. In situ Raman experiments of the silica-water, alumina-water, and alumina water systems were performed in an externally heated Bassett-type diamond-anvil cell at the Department of Geological Sciences, University of Michigan. Natural quartz samples and synthetic ruby samples were used in the experiments. Samples were loaded in the sample chamber with a water pressure medium. All experiments used rhenium gaskets of uniform thickness with a 500 mum drill hole for the sample chamber. Temperature was measured using K-type thermocouples encompassing both the upper and lower diamond anvils. Pressures are obtained on the basis of the Raman shift of the 464 cm-1 quartz mode where possible or the Raman shift of the tips of the diamond anvils according to a method developed in this work. This work characterizes the state of stress in the diamond anvil cell, which is used as the basis for the pressure calibration using only the diamond anvils. Raman measurements of silicate fluid confirm the presence of H4 SiO4 and H6Si2O7 in solution and expand the pressure range for in-situ structural observations in the silica-water system. Additionally, we identify the presence of another silica species present at mantle conditions, which occurs at long time scales in the diamond cell. This study provides the first in situ data in the alumina-water and alumina-silica-water systems at pressures and temperatures relevant to the slab environment. Al(OH) 3 appears to be the dominant form of alumina present under these conditions and in the alumina

  14. Melting temperatures of MgO under high pressure determined by micro-texture observation

    Science.gov (United States)

    Kimura, T.; Ohfuji, H.; Nishi, M.; Irifune, T.

    2016-12-01

    Periclase (MgO) is the second abundant mineral after bridgmanite in the Earth's lower mantle, and its melting temperature (Tm) under pressure is important to constrain the chemical composition of ultra-deep magma formed near the mantle-core boundary. However, the melting behavior is highly controversial among previous studies: a laser-heated diamond anvil cell (LHDAC) study reported a melting curve with a dTm/dP of 30 K/GPa at zero pressure [1], while several theoretical computations gave substantially higher dTm/dP of 90 100 K/GPa [2,3]. We performed a series of LHDAC experiments for measurements of Tm of MgO under high pressure, using single crystal MgO as the starting material. The melting was detected by using micro-texture observations of the quenched samples. We found that the laser-heated area of the sample quenched from the Tm in previous LHDAC experiments [1] showed randomly aggregated granular crystals, which was not caused by melting, but by plastic deformation of the sample. This suggests that the Tms of their study were substantially underestimated. On the other hand, the sample recovered from the temperature higher by 1500-1700 K than the Tms in previous LHDAC experiments showed a characteristic internal texture comparable to the solidification texture typically shown in metal casting. We determined the Tms based on the observation of this texture up to 32 GPa. Fitting our Tms to the Simon equation yields dTm/dP of 82 K/GPa at zero pressure, which is consistent with those of the theoretical predictions (90 100 K/GPa) [2,3]. Extrapolation of the present melting curve of MgO to the pressure of the CMB (135 GPa) gives a melting temperature of 8900 K. The present steep melting slope offers the eutectic composition close to peridotite (in terms of Mg/Si ratio) throughout the lower mantle conditions. According to the model for sink/float relationship between the solid mantle and the magma [4], a considerable amount of iron (Fe/(Mg+Fe) > 0.24) is expected

  15. High Pressure and High Temperature State of Oxygen Enriched Ice

    Science.gov (United States)

    LI, M.; Zhang, S.; Jeanloz, R.; Militzer, B.

    2016-12-01

    Interior models for Uranus and Neptune include a hydrogen/helium/water outer envelope and a core of rock and metal at the center, with superionic water-rich ice proposed as comprising an intermediate layer. Here we consider an oxygen-enriched ice, such as H2O2 hydrogen peroxide (± water), that could form through chemical reaction between water-rich and underlying rocky (i.e., oxygen-rich) layers. As oxygen and its compounds (e.g., H2O, SiO2) form metallic fluids at pressures above 100-150 GPa, the problem amounts to considering oxygen alloying of semiconducting or metallic water. The density of H2O2 is 1.45 g/cc at ambient pressure and 0° C, increasing to 1.71 g/cc in the solid state at about -20° C. There are no Hugoniot data beyond 30 GPa, so we estimated Hugoniots for H2O2 with different initial densities, using both a mixing model based on Hugoniot data for H2O2 and 1/2 O2 (molar volume summation under pressure) and ab initio calculations for unreacted H2O2. The results agree with each other to pressures of about 200 GPa, and the ab initio calculations show evidence of a superionic state at temperatures as low as 500 K, much lower than for water ice. Hydrogen peroxide is expected to be liquid along planetary isentropes for Uranus and Neptune, suggesting that H2O2 may not be present as a pure compound in these planets. Instead, oxygen-enriched H2O ice may be the relevant form of water and oxygen, and might be produced in the laboratory by way of dynamic compression of H2O2 or laser-heating of statically compressed H2O + O2 and/or H2O2.

  16. Optimisation of phenolics recovery from Vitex agnus-castus Linn. leaves by high-pressure and temperature extraction.

    Science.gov (United States)

    Lataoui, Mohammed; Seffen, Mongi; Aliakbarian, Bahar; Casazza, Alessandro Alberto; Converti, Attilio; Perego, Patrizia

    2014-01-01

    To optimise recovery of phenolics from Vitex agnus-castus Linn., a non-conventional high-pressure (2-24 bar) and temperature (100-180°C) extraction method was used under nitrogen atmosphere with methanol as a solvent. Optimal temperature was between 100 and 140°C, and optimal extraction time was about one half that of conventional solid/liquid extraction at room temperature. Final yields of total polyphenols, total flavonoids, o-diphenols and anthocyanins extraction were 2.0, 3.0, 2.5 and 11-fold those obtained by conventional extraction.

  17. Crystallization of TiO2 Nanotubes by In Situ Heating TEM

    KAUST Repository

    Casu, Alberto

    2018-01-15

    The thermally-induced crystallization of anodically grown TiO2 amorphous nanotubes has been studied so far under ambient pressure conditions by techniques such as differential scanning calorimetry and in situ X-ray diffraction, then looking at the overall response of several thousands of nanotubes in a carpet arrangement. Here we report a study of this phenomenon based on an in situ transmission electron microscopy approach that uses a twofold strategy. First, a group of some tens of TiO2 amorphous nanotubes was heated looking at their electron diffraction pattern change versus temperature, in order to determine both the initial temperature of crystallization and the corresponding crystalline phases. Second, the experiment was repeated on groups of few nanotubes, imaging their structural evolution in the direct space by spherical aberration-corrected high resolution transmission electron microscopy. These studies showed that, differently from what happens under ambient pressure conditions, under the microscope’s high vacuum (p < 10−5 Pa) the crystallization of TiO2 amorphous nanotubes starts from local small seeds of rutile and brookite, which then grow up with the increasing temperature. Besides, the crystallization started at different temperatures, namely 450 and 380 °C, when the in situ heating was performed irradiating the sample with electron beam energy of 120 or 300 keV, respectively. This difference is due to atomic knock-on effects induced by the electron beam with diverse energy.

  18. H2O temperature sensor for low-pressure flames using tunable diode laser absorption near 2.9 νm

    KAUST Repository

    Li, Sijie; Farooq, Aamir; Hanson, Ronald Kenneth

    2011-01-01

    Making use of a newly available rapid-tuning diode laser operating at wavelengths up to 2.9 νm, an absorption-based temperature sensor was developed for in situ measurements in low-pressure flames. Based on the systematic analysis of H2O vapor

  19. A system for traceable measurement of the microwave complex permittivity of liquids at high pressures and temperatures

    International Nuclear Information System (INIS)

    Dimitrakis, G A; Robinson, J; Kingman, S; Lester, E; George, M; Poliakoff, M; Harrison, I; Gregory, A P; Lees, K

    2009-01-01

    A system has been developed for direct traceable dielectric measurements on liquids at high pressures and temperatures. The system consists of a coaxial reflectometric sensor terminated by a metallic cylindrical cell to contain the liquid. It has been designed for measurements on supercritical liquids, but as a first step measurements on dielectric reference liquids were performed. This paper reports on a full evaluation of the system up to 2.5 GHz using methanol, ethanol and n-propanol at pressures up to 9 MPa and temperatures up to 273 °C. A comprehensive approach to the evaluation of uncertainties using Monte Carlo modelling is used

  20. Gas erosion of impeller housing in the operation of a high-temperature, high-pressure helium circulator

    International Nuclear Information System (INIS)

    Sanders, J.P.; Heestand, R.L.; Young, H.C.

    1988-01-01

    Three gas-bearing circulators are installed in series in a high-pressure, high-temperature loop to provide helium flow up to 0.47 m 3 /s at a total head of 78 kJ/kg. The design pressure is 10.7 MPa, and temperatures of 1000 deg. C can be obtained in the test section. The inlet temperature to the circulators is limited to 450 deg. C. The 200-kW motor for each circulator is enclosed in the pressure boundary, and the motor is cooled by circulating the gas within the cavity over a water-cooled coil. The full operating speed is 23,500 rpm. A full-flow filter, absolute for particulate above 10 μm, is installed upstream of the circulator to protect the gas bearing surfaces. The minimum clearances between these surfaces during operation are in the range of 15 to 30 μm. During a routine examination of the circulator, deep V-shaped grooves were found in the stationary surface of this cavity. At the same time, a very fine, dark particulate was observed in crevices of the housing. At first it was assumed that the grooves were formed by particulate erosion; however, examination of the grooves and discussions with persons experienced with large circulator operation changed this opinion. Erosion caused by particulate is characteristically rounded on the bottom and has a greater width to depth aspect than the V-shaped grooves, which were observed. Analysis of the particulate indicated that it was essentially the material of the housing that had undergone reactions with impurities in the circulating gas. It was subsequently concluded that the impeller housing had not been heat treated in a sufficiently oxidizing atmosphere after machining to form an adherent oxide coating. This suboxide coating was eroded by the shear forces in the gas. The exposed layer of metal was then further oxidized by the impurities in the gas, and these layers of oxide were successively eroded to produce the grooves. This erosion problem was eliminated by machining a ring of the same material, heat

  1. High temperature vapor pressures of stainless steel type 1.4970 and of some other pure metals from laser evaporation

    International Nuclear Information System (INIS)

    Bober, M.; Singer, J.

    1984-10-01

    For the safety analysis of nuclear reactors vapor pressure data of stainless steel are required up to temperatures exceeding 4000 K. In analogy to the classic boiling point method a new technique was developed to measure the high-temperature vapor pressures of stainless steel and other metals from laser vaporization. A fast pyrometer, an ion current probe and an image converter camera are used to detect incipient boiling from the time-temperature curve. The saturated-vapor pressure curves of stainless steel (Type 1.4970), being a cladding material of the SNR 300 breeder reactor, and of molybdenum are experimentally determined in the temperature ranges of 2800-3900 K and 4500-5200 K, respectively. The normal boiling points of iron, nickel, titanium, vanadium and zirconium are verified. Besides, spectral emissivity values of the liquid metals are measured at the pyrometer wavelengths of 752 nm and/or 940 nm. (orig.) [de

  2. High-pressure modulation of the structure of the bacterial photochemical reaction center at physiological and cryogenic temperatures

    Science.gov (United States)

    Timpmann, Kõu; Kangur, Liina; Lõhmus, Ants; Freiberg, Arvi

    2017-07-01

    The optical absorption and fluorescence response to external high pressure of the reaction center membrane chromoprotein complex from the wild-type non-sulfur photosynthetic bacterium Rhodobacter sphaeroides was investigated using the native pigment cofactors as local molecular probes of the reaction center structure at physiological (ambient) and cryogenic (79 K) temperatures. In detergent-purified complexes at ambient temperature, abrupt blue shift and accompanied broadening of the special pair band was observed at about 265 MPa. These reversible in pressure features were assigned to a pressure-induced rupture of a lone hydrogen bond that binds the photo-chemically active L-branch primary electron donor bacteriochlorophyll cofactor to the surrounding protein scaffold. In native membrane-protected complexes the hydrogen bond rupture appeared significantly restricted and occurred close to about 500 MPa. The free energy change associated with the rupture of the special pair hydrogen bond in isolate complexes was estimated to be equal to about 12 kJ mol-1. In frozen samples at cryogenic temperatures the hydrogen bond remained apparently intact up to the maximum utilized pressure of 600 MPa. In this case, however, heterogeneous spectral response of the cofactors from the L-and M-branches was observed due to anisotropic build-up of the protein structure. While in solid phase, the special pair fluorescence as a function of pressure exactly followed the respective absorption spectrum at a constant Stokes shift, at ambient temperature, the two paths began to deviate strongly from one other at the hydrogen bond rupture pressure. This effect was tentatively interpreted by different emission properties of hydrogen-bound and hydrogen-unbound special pair exciton states.

  3. Fabrication of All-SiC Fiber-Optic Pressure Sensors for High-Temperature Applications.

    Science.gov (United States)

    Jiang, Yonggang; Li, Jian; Zhou, Zhiwen; Jiang, Xinggang; Zhang, Deyuan

    2016-10-17

    Single-crystal silicon carbide (SiC)-based pressure sensors can be used in harsh environments, as they exhibit stable mechanical and electrical properties at elevated temperatures. A fiber-optic pressure sensor with an all-SiC sensor head was fabricated and is herein proposed. SiC sensor diaphragms were fabricated via an ultrasonic vibration mill-grinding (UVMG) method, which resulted in a small grinding force and low surface roughness. The sensor head was formed by hermetically bonding two layers of SiC using a nickel diffusion bonding method. The pressure sensor illustrated a good linearity in the range of 0.1-0.9 MPa, with a resolution of 0.27% F.S. (full scale) at room temperature.

  4. Equations for calculating hydrogeochemical reactions of minerals and gases such as CO2 at high pressures and temperatures

    Science.gov (United States)

    Appelo, C. A. J.; Parkhurst, D. L.; Post, V. E. A.

    2014-01-01

    Calculating the solubility of gases and minerals at the high pressures of carbon capture and storage in geological reservoirs requires an accurate description of the molar volumes of aqueous species and the fugacity coefficients of gases. Existing methods for calculating the molar volumes of aqueous species are limited to a specific concentration matrix (often seawater), have been fit for a limited temperature (below 60 °C) or pressure range, apply only at infinite dilution, or are defined for salts instead of individual ions. A more general and reliable calculation of apparent molar volumes of single ions is presented, based on a modified Redlich-Rosenfeld equation. The modifications consist of (1) using the Born equation to calculate the temperature dependence of the intrinsic volumes, following Helgeson-Kirkham-Flowers (HKF), but with Bradley and Pitzer’s expression for the dielectric permittivity of water, (2) using the pressure dependence of the extended Debye-Hückel equation to constrain the limiting slope of the molar volume with ionic strength, and (3) adopting the convention that the proton has zero volume at all ionic strengths, temperatures and pressures. The modifications substantially reduce the number of fitting parameters, while maintaining or even extending the range of temperature and pressure over which molar volumes can be accurately estimated. The coefficients in the HKF-modified-Redlich-Rosenfeld equation were fitted by least-squares on measured solution densities. The limiting volume and attraction factor in the Van der Waals equation of state can be estimated with the Peng-Robinson approach from the critical temperature, pressure, and acentric factor of a gas. The Van der Waals equation can then be used to determine the fugacity coefficients for pure gases and gases in a mixture, and the solubility of the gas can be calculated from the fugacity, the molar volume in aqueous solution, and the equilibrium constant. The coefficients for the

  5. 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.

  6. 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.

  7. Phase Transition Behavior of LiCr0.35Mn0.65O2 under High Pressure by Electrical Conductivity Measurement

    International Nuclear Information System (INIS)

    Xiao-Yan, Cui; Ting-Jing, Hu; Yong-Hao, Han; Chun-Xiao, Gao; Gang, Peng; Cai-Long, Liu; Bao-Jia, Wu; Yue, Wang; Bao, Liu; Wan-Bin, Ren; Yan, Li; Ning-Ning, Su; Guang-Tian, Zou; Fei, Du; Gang, Chen

    2010-01-01

    The electrical conductivity of powdered LiCr 0.35 Mn 0.65 O 2 is measured under high pressure up to 26.22 GPa in the temperature range 300–413 K by using a diamond anvil cell. It is found that both conductivity and activation enthalpy change discontinuously at 5.36 GPa and 21.66 GPa. In the pressure range 1.10–5.36 GPa, pressure increases the activation enthalpy and reduces the carrier scattering, which finally leads to the conductivity increase. In the pressure ranges 6.32–21.66 GPa and 22.60–26.22 GPa, the activation enthalpy decreases with pressure increasing, which has a positive contribution to electrical conductivity increase. Two pressure-induced structural phase transitions are found by in-situ x-ray diffraction under high pressure, which results in the discontinuous changes of conductivity and activation enthalpy. (condensed matter: structure, mechanical and thermal properties)

  8. Evaluation of anti-scale property of CrN coatings at high temperature and high pressure

    International Nuclear Information System (INIS)

    Honda, Tomomi; Iwai, Yoshiro; Uno, Ryoji; Yoshinaga, Shigeki

    2007-01-01

    It is well known that oxide scale which adheres to the inner wall of the nozzle in nuclear power plant causes a serious problem. This study was carried out to obtain the knowledge about initiation and deposition behavior of oxide scale on the surface of SUS304 stainless steel and the evaluation of anti-scale property of chromium nitride (CrN) coatings at high temperature and high pressure. SUS304 stainless steel and CrN coating specimens were heated in water up to 200degC for more than 250 hours. Obtained results are summarized as follows. Initiation of the scale started from corrosive part of SUS304 stainless steel and the scale grows by deposition of magnetite particles. CrN coating can be applied to prevent the initiation and deposition of oxide scale. (author)

  9. High-pressure tolerance of earthworm fibrinolytic and digestive enzymes.

    Science.gov (United States)

    Akazawa, Shin-Ichi; Tokuyama, Haruka; Sato, Shunsuke; Watanabe, Toshinori; Shida, Yosuke; Ogasawara, Wataru

    2018-02-01

    Earthworms contain several digestive and therapeutic enzymes that are beneficial to our health and useful for biomass utilization. Specifically, earthworms contain potent fibrinolytic enzymes called lumbrokinases, which are highly stable even at room temperature and remain active in dried earthworm powder. However, the high-temperature sterilization method leads to the inactivation of enzymes. Therefore, we investigated the effect of high-pressure treatment (HPT) (from 0.1 MPa to 500 MPa at 25°C and 50°C) on the enzymatic activity of lumbrokinase (LK), α-amylase (AMY), endoglucanase (EG), β-glucosidase (BGL), and lipase (LP) of the earthworm Eisenia fetida, Waki strain, and its sterilization ability in producing dietary supplement. LK showed thermo- and high-pressure tolerance. In addition, HPT may have resulted in pressure-induced stabilization and activation of LK. Although AMY activity was maintained up to 400 MPa at 25°C, the apparent activity decreased slightly at 50°C with HPT. EG showed almost the same pattern as AMY. However, it is possible that the effects of temperature and pressure compensated each other under 100 MPa at 50°C. BGL was shown to be a pressure- and temperature-sensitive enzyme, and LP showed a thermo- and high-pressure tolerance. The slight decrease in apparent activity occurred under 200 MPa at both temperatures. Furthermore, the low-temperature and pressure treatment completely sterilized the samples. These results provide a basis for the development of a novel earthworm dietary supplement with fibrinolytic and digestive activity and of high-pressure-tolerant enzymes to be used for biomass pretreatment. Copyright © 2017 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

  10. Pressure-Induced Polyamorphic Transition in Nanoscale TiO2

    International Nuclear Information System (INIS)

    Swamy, Varghese; Muddle, Barry C.

    2009-01-01

    The detection and characterization of pressure-induced amorphization in 20 GPa and ambient temperature is documented. The characterization employed in situ high-pressure angle-dispersive synchrotron X-ray diffraction and Raman spectroscopy in diamond-anvil cells. Comparative Raman spectroscopy allows the local structures of the high-density amorphous (HDA) form obtained at high pressures and its low-pressure (<10-15 GPa) low-density amorphous (LDA) analogue to be related to the baddeleyite-TiO2 and TiO2-II structures, respectively. The pressure-induced amorphization and the HDA-LDA transition in nanoscale TiO2 bear broad similarities to transitions in the Si and H2O systems.

  11. Effect of temperature and density fluctuations on the spatially heterogeneous dynamics of glass-forming Van der Waals liquids under high pressure.

    Science.gov (United States)

    Koperwas, K; Grzybowski, A; Grzybowska, K; Wojnarowska, Z; Sokolov, A P; Paluch, M

    2013-09-20

    In this Letter, we show how temperature and density fluctuations affect the spatially heterogeneous dynamics at ambient and elevated pressures. By using high-pressure experimental data for van der Waals liquids, we examine contributions of the temperature and density fluctuations to the dynamics heterogeneity. We show that the dynamic heterogeneity decreases significantly with increasing pressure at a constant structural relaxation time (isochronal condition), while the broadening of the relaxation spectrum remains constant. This observation questions the relationship between spectral broadening and dynamic heterogeneity.

  12. 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

  13. In-situ heating test in the sedimentary soft rock. Part 3. Monitoring of the extent of high temperature zone by resistivity tomography

    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 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 50m. Resistivity monitoring is thought to be effective to map the extent of high temperature zone. So resistivity tomography was conducted during the heating. The results demonstrated that the resistivity of the rock mass around the heater well was decreased and this area was gradually expanded from the heated area during the heating. Resistivity of rock is proportional to that of pore water which is known to decrease with increasing temperature. This suggests that high temperature zone 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 heated area by nuclear waste. (author)

  14. Fabrication of All-SiC Fiber-Optic Pressure Sensors for High-Temperature Applications

    Directory of Open Access Journals (Sweden)

    Yonggang Jiang

    2016-10-01

    Full Text Available Single-crystal silicon carbide (SiC-based pressure sensors can be used in harsh environments, as they exhibit stable mechanical and electrical properties at elevated temperatures. A fiber-optic pressure sensor with an all-SiC sensor head was fabricated and is herein proposed. SiC sensor diaphragms were fabricated via an ultrasonic vibration mill-grinding (UVMG method, which resulted in a small grinding force and low surface roughness. The sensor head was formed by hermetically bonding two layers of SiC using a nickel diffusion bonding method. The pressure sensor illustrated a good linearity in the range of 0.1–0.9 MPa, with a resolution of 0.27% F.S. (full scale at room temperature.

  15. A Three-Dimensional Porous Conducting Polymer Composite with Ultralow Density and Highly Sensitive Pressure Sensing Properties

    International Nuclear Information System (INIS)

    Su, J. D.; Sun, J.L.; Chen, J.H.; Jia, X.Sh.; Li, J.T.; Yan, X.; Long, Y.Z.; Lou, T.; Yan, X.; Long, Y.Z.

    2016-01-01

    An ultra light conducting poly aniline/Si C/polyacrylonitrile (PANI/Si C/PAN) composite was fabricated by in situ polymerization of aniline monomer on the surface of fibers in Si C/PAN aerogel. The Si C/PAN aerogel was obtained by electro spinning, freeze-drying, and heat treatment. The ingredient, morphology, structure, and electrical properties of the aerogel before and after in situ polymerization were investigated by X-ray powder diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), scanning electron microscope (SEM), and voltage-current characteristic measurement. The thermostability of PANI/Si C/PAN composite was investigated by thermogravimetric analysis (TGA) and electrical resistance measured at different temperatures. The density of the PANI/SiC/PAN composite was approximately 0.211gcm - 3, the porosity was 76.44%, and the conductivity was 0.013Sm - 1. The pressure sensing properties were evaluated at room temperature. The electrical resistance of as-prepared sample decreased gradually with the increase of pressure. Furthermore, the pressure sensing process was reversible and the response time was short (about 1s). This composite may have application in pressure sensor field

  16. A Three-Dimensional Porous Conducting Polymer Composite with Ultralow Density and Highly Sensitive Pressure Sensing Properties

    Directory of Open Access Journals (Sweden)

    Jin-Dong Su

    2016-01-01

    Full Text Available An ultralight conducting polyaniline/SiC/polyacrylonitrile (PANI/SiC/PAN composite was fabricated by in situ polymerization of aniline monomer on the surface of fibers in SiC/PAN aerogel. The SiC/PAN aerogel was obtained by electrospinning, freeze-drying, and heat treatment. The ingredient, morphology, structure, and electrical properties of the aerogel before and after in situ polymerization were investigated by X-ray powder diffraction (XRD, Fourier transform infrared spectroscopy (FT-IR, scanning electron microscope (SEM, and voltage-current characteristic measurement. The thermostability of PANI/SiC/PAN composite was investigated by thermogravimetric analysis (TGA and electrical resistance measured at different temperatures. The density of the PANI/SiC/PAN composite was approximately 0.211 g cm−3, the porosity was 76.44%, and the conductivity was 0.013 S m−1. The pressure sensing properties were evaluated at room temperature. The electrical resistance of as-prepared sample decreased gradually with the increase of pressure. Furthermore, the pressure sensing process was reversible and the response time was short (about 1 s. This composite may have application in pressure sensor field.

  17. Pressure Dome for High-Pressure Electrolyzer

    Science.gov (United States)

    Norman, Timothy; Schmitt, Edwin

    2012-01-01

    A high-strength, low-weight pressure vessel dome was designed specifically to house a high-pressure [2,000 psi (approx. = 13.8 MPa)] electrolyzer. In operation, the dome is filled with an inert gas pressurized to roughly 100 psi (approx. = 690 kPa) above the high, balanced pressure product oxygen and hydrogen gas streams. The inert gas acts to reduce the clamping load on electrolyzer stack tie bolts since the dome pressure acting axially inward helps offset the outward axial forces from the stack gas pressure. Likewise, radial and circumferential stresses on electrolyzer frames are minimized. Because the dome is operated at a higher pressure than the electrolyzer product gas, any external electrolyzer leak prevents oxygen or hydrogen from leaking into the dome. Instead the affected stack gas stream pressure rises detectably, thereby enabling a system shutdown. All electrical and fluid connections to the stack are made inside the pressure dome and require special plumbing and electrical dome interfaces for this to be accomplished. Further benefits of the dome are that it can act as a containment shield in the unlikely event of a catastrophic failure. Studies indicate that, for a given active area (and hence, cell ID), frame outside diameter must become ever larger to support stresses at higher operating pressures. This can lead to a large footprint and increased costs associated with thicker and/or larger diameter end-plates, tie-rods, and the frames themselves. One solution is to employ rings that fit snugly around the frame. This complicates stack assembly and is sometimes difficult to achieve in practice, as its success is strongly dependent on frame and ring tolerances, gas pressure, and operating temperature. A pressure dome permits an otherwise low-pressure stack to operate at higher pressures without growing the electrolyzer hardware. The pressure dome consists of two machined segments. An O-ring is placed in an O-ring groove in the flange of the bottom

  18. High-resistive layers obtained through periodic growth and in situ annealing of InGaN by metalorganic chemical vapor deposition

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Shuo; Ma, Ping, E-mail: maping@semi.ac.cn; Liu, Boting; Wu, Dongxue; Li, Jinmin [Research and Development Center for Solid State Lighting, Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083 (China); Huang, Yuliang [Beijing Engineering Research Center for the 3rd Generation Semiconductor Materials and Application, Beijing 100083 (China); Wang, Junxi [State Key Laboratory of Solid State Lighting, Beijing 100083 (China)

    2016-06-15

    High-resistive layers were obtained by periodic growth and in situ annealing of InGaN. The effect of the annealing temperature of InGaN on the indium content and the material sheet resistive was investigated. The indium content decreased as the increase of in situ annealing temperature. Additionally, the material sheet resistance increased with the increase of the in situ annealing temperature for the annealed samples and reached 2 × 10{sup 10}Ω/sq in the light and 2 × 10{sup 11}Ω/sq in the dark when the in situ annealing temperature reached 970{sup ∘}C. The acquirement of high-resistive layers is attributed to the generation of indium vacancy-related defects. Introducing indium vacancy-related defects to compensate background carriers can be an effective method to grow high-resistance material.

  19. High-resistive layers obtained through periodic growth and in situ annealing of InGaN by metalorganic chemical vapor deposition

    International Nuclear Information System (INIS)

    Zhang, Shuo; Ma, Ping; Liu, Boting; Wu, Dongxue; Li, Jinmin; Huang, Yuliang; Wang, Junxi

    2016-01-01

    High-resistive layers were obtained by periodic growth and in situ annealing of InGaN. The effect of the annealing temperature of InGaN on the indium content and the material sheet resistive was investigated. The indium content decreased as the increase of in situ annealing temperature. Additionally, the material sheet resistance increased with the increase of the in situ annealing temperature for the annealed samples and reached 2 × 10"1"0Ω/sq in the light and 2 × 10"1"1Ω/sq in the dark when the in situ annealing temperature reached 970"∘C. The acquirement of high-resistive layers is attributed to the generation of indium vacancy-related defects. Introducing indium vacancy-related defects to compensate background carriers can be an effective method to grow high-resistance material.

  20. Quasi-dynamic pressure and temperature

    International Nuclear Information System (INIS)

    Zaug, J M.; Farber, D L; Blosch, L L; Craig, I M; Hansen, D W; Aracne-Ruddle, C M; Shuh, D K

    1998-01-01

    The phase transformation of(beta)-HMX ( and lt; 0.5% RDX) to the(delta) phase has been studied for over twenty years and more recently with an optically sensitive second harmonic generation technique. Shock studies of the plastic binder composites of HMX have indicated that the transition is perhaps irreversible, a result that concurs with the static pressure results published by F. Goetz et al.[l] in 1978. However the stability field favors the(beta) polymorph over(delta) as pressure is increased (up to 5.4 GPa) along any sensible isotherm. In this experiment strict control of pressure and temperature is maintained while x-ray and optical diagnostics are applied to monitor the conformational dynamics of HMX. Unlike the temperature induced(beta) - and gt;(delta) transition, the pressure induced is heterogeneous in nature. The room pressure and temperature(delta) - and gt;(beta) transition is not immediate although it seems to occur over tens of hours. Transition points and kinetics are path dependent and so this paper describes our work in progress