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Sample records for high pressure conditions

  1. Practical conditions in the neutron diffraction under high pressure

    International Nuclear Information System (INIS)

    Kamigaki, Kazuo; Ohashi, Masayoshi

    1993-01-01

    Practical analysis is made on some conditions in utilizing neutrons for the study of atomistic structure of materials under high pressure. Investigation is made on the geometrical conditions; size of the specimen, width of slits, and the rate of extra-scattering. Experiments are performed on the effects of absorption by high pressure cell and the disturbance due to an overlapping of diffraction peaks. An observation is presented on the pressure-induced transformation in RbBr. (author)

  2. [The oral cavity condition in patients with high blood pressure].

    Science.gov (United States)

    Rosiak, Joanna; Kubić-Filiks, Beata; Szymańska, Jolanta

    2015-10-01

    The incidence of high blood pressure in adults is estimated at ca. 30-40% of the general population. Both hypertension disease and hypertensive drugs affect the condition of the patients' oral cavity. A review of the current literature shows that disorders most frequently found in the masticatory organ of patients with hypertension include: xerostomia, changes in salivary glands, gum hypertrophy, lichenoid lesions, taste disorders, and paraesthesias. The authors emphasize that patients with high blood pressure, along with the treatment of the underlying disease, should receive prophylactic and therapeutic dental care. This would enable reduction and/or elimination of unpleasant complaints, and also help prevent the emergence of secondary disorders in the patients' oral cavity as a result of hypertension pharmacotherapy. © 2015 MEDPRESS.

  3. 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)

  4. Hulls and structural material waste conditioning by high pressure compaction

    International Nuclear Information System (INIS)

    Frotscher, H.

    1991-01-01

    Since 1986 KfK is developing a conditioning process. Main subjects of the investigations were the development of the production technique and the planning of the most important equipments of the process under remote conditions. The process is based on an extensive program of experiments. Inactive bulks of hulls and structural material components were compacted using maximum axial pressure load of about 300 MPa. The product density as function of press force was experimentally determinated. The mechanical loads of the press and tools were estimated for the design of these equipments. The hydraulic press consists a horizontal four-cylinder press. The maximum force of the press is 25 MN. The main advantage is the modular design of the press which is open on all sides. Especially the free accessibility from top is ensured. The report also represents relevant radiological data of the alternative product. Co-60 is the dominating activity of the product due to the effects of the heat production. An amount of 10 kg hull waste or 25 kg top and bottom pieces of the spent fuel assemblies per package is already beyond the Co-60 limit of the KONRAD regulations. The nuclear thermal power of a filled container is approximately sixty times lower compared with a vitrified HLW-container. Since the product shows thermal stability beyond 200 0 C, this it is suited for a combined disposal together with vitrified HLW-containers in salt bore holes of a geological disposal. The preliminary cost evaluation is based on a reprocessing throughput of 500 t HM per year and volume reduction factor of 5.3. Accordingly there are produced 300 waste packages with hulls only or 625 units with hulls and top and bottom pieces which require 1.6 or 2.3 millions DM respectively

  5. 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.

  6. 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.

  7. 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

  8. 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.

  9. High-pressure polymorphs in Yamato-790729 L6 chondrite and their significance for collisional conditions

    Science.gov (United States)

    Kato, Yukako; Sekine, Toshimori; Kayama, Masahiko; Miyahara, Masaaki; Yamaguchi, Akira

    2017-12-01

    Shock pressure recorded in Yamato (Y)-790729, classified as L6 type ordinary chondrite, was evaluated based on high-pressure polymorph assemblages and cathodoluminescence (CL) spectra of maskelynite. The host-rock of Y-790729 consists mainly of olivine, low-Ca pyroxene, plagioclase, metallic Fe-Ni, and iron-sulfide with minor amounts of phosphate and chromite. A shock-melt vein was observed in the hostrock. Ringwoodite, majorite, akimotoite, lingunite, tuite, and xieite occurred in and around the shock-melt vein. The shock pressure in the shock-melt vein is about 14-23 GPa based on the phase equilibrium diagrams of high-pressure polymorphs. Some plagioclase portions in the host-rock occurred as maskelynite. Sixteen different CL spectra of maskelynite portions were deconvolved using three assigned emission components (centered at 2.95, 3.26, and 3.88 eV). The intensity of emission component at 2.95 eV was selected as a calibrated barometer to estimate shock pressure, and the results indicate pressures of about 11-19 GPa. The difference in pressure between the shock-melt vein and host-rock might suggest heterogeneous shock conditions. Assuming an average shock pressure of 18 GPa, the impact velocity of the parent-body of Y-790729 is calculated to be 1.90 km s-1. The parent-body would be at least 10 km in size based on the incoherent formation mechanism of ringwoodite in Y-790729.

  10. Design and Application of a High Sensitivity Piezoresistive Pressure Sensor for Low Pressure Conditions

    Science.gov (United States)

    Yu, Huiyang; Huang, Jianqiu

    2015-01-01

    In this paper, a pressure sensor for low pressure detection (0.5 kPa–40 kPa) is proposed. In one structure (No. 1), the silicon membrane is partly etched to form a crossed beam on its top for stress concentration. An aluminum layer is also deposited as part of the beam. Four piezoresistors are fabricated. Two are located at the two ends of the beam. The other two are located at the membrane periphery. Four piezoresistors connect into a Wheatstone bridge. To demonstrate the stress concentrate effect of this structure, two other structures were designed and fabricated. One is a flat membrane structure (No. 2), the other is a structure with the aluminum beam, but without etched silicon (No. 3). The measurement results of these three structures show that the No.1 structure has the highest sensitivity, which is about 3.8 times that of the No. 2 structure and 2.7 times that of the No. 3 structure. They also show that the residual stress in the beam has some backside effect on the sensor performance. PMID:26371001

  11. Effect of mixing rule boundary conditions on high pressure (liquid + liquid) equilibrium prediction

    International Nuclear Information System (INIS)

    Hsieh, Min-Kang; Lin, Shiang-Tai

    2012-01-01

    Highlights: ► Prediction of LLE from the combined use of EOS and liquid model are examined. ► The mixing rule used affects the predicted pressure dependence of LLE. ► MHV1 mixing rule predicts decent LLE at low pressures. ► WS mixing rule predicts more accurate excess volume and LLE at high pressures. ► The hybrid of MHV1 and WS mixing rule gives overall the best predictions. - Abstract: We examine the prediction of high pressure (liquid + liquid) equilibrium (LLE) from the Peng–Robinson equation with three excess Gibbs free energy (G ex )-based mixing rules (MR): the first order modified Huron–Vidal (MHV1), the Wong–Sandler (WS), and a hybrid of these two (referred to as G ex B 2 ). These mixing rules differ by the boundary conditions used for determination of the temperature and composition dependence of parameters a and b in the PR EOS. The condition of matching the excess Gibbs free energy from the EOS at zero pressure to that from the G ex model, used in MHV1 and G ex B 2 MR, leads to a similar miscibility gap from PR EOS and the G ex model used. On the other hand, the condition of matching excess Helmholtz energy from the EOS at infinite pressure to that from the G ex model, used in the WS MR, shows remarkable deviations. The condition of quadratic composition dependence in the second virial coefficient (B 2 ), used in WS and G ex B 2 MR, allows for both positive and negative values in the molar excess volume. Depending on the mixture, either the increase or decrease of the miscibility gap with pressure can be observed when the WS or the G ex B 2 MR is used. The condition of linear combination of molecular sizes of each component used in the MHV1 MR, however, often leads to small, positive molar excess volumes. As a consequence, the predicted LLE from using the MHV1 MR are insensitive to pressure. Therefore, we find that the G ex B 2 mixing rule provides the best predictive power for the LLE over a wide range of temperature and pressure.

  12. 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.

  13. 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)

  14. Parameterised Model of 2D Combustor Exit Flow Conditions for High-Pressure Turbine Simulations

    Directory of Open Access Journals (Sweden)

    Marius Schneider

    2017-12-01

    Full Text Available An algorithm is presented generating a complete set of inlet boundary conditions for Reynolds-averaged Navier–Stokes computational fluid dynamics (RANS CFD of high-pressure turbines to investigate their interaction with lean and rich burn combustors. The method shall contribute to understanding the sensitivities of turbine aerothermal performance in a systematic approach. The boundary conditions are based on a set of input parameters controlling velocity, temperature, and turbulence fields. All other quantities are derived from operating conditions and additional modelling assumptions. The algorithm is coupled with a CFD solver by applying the generated profiles as inlet boundary conditions. The successive steps to derive consistent flow profiles are described and results are validated against flow fields extracted from combustor CFD.

  15. Computational Fluid Dynamic Simulation of Single Bubble Growth under High-Pressure Pool Boiling Conditions

    Directory of Open Access Journals (Sweden)

    Janani Murallidharan

    2016-08-01

    Full Text Available Component-scale modeling of boiling is predominantly based on the Eulerian–Eulerian two-fluid approach. Within this framework, wall boiling is accounted for via the Rensselaer Polytechnic Institute (RPI model and, within this model, the bubble is characterized using three main parameters: departure diameter (D, nucleation site density (N, and departure frequency (f. Typically, the magnitudes of these three parameters are obtained from empirical correlations. However, in recent years, efforts have been directed toward mechanistic modeling of the boiling process. Of the three parameters mentioned above, the departure diameter (D is least affected by the intrinsic uncertainties of the nucleate boiling process. This feature, along with its prominence within the RPI boiling model, has made it the primary candidate for mechanistic modeling ventures. Mechanistic modeling of D is mostly carried out through solving of force balance equations on the bubble. Forces incorporated in these equations are formulated as functions of the radius of the bubble and have been developed for, and applied to, low-pressure conditions only. Conversely, for high-pressure conditions, no mechanistic information is available regarding the growth rates of bubbles and the forces acting on them. In this study, we use direct numerical simulation coupled with an interface tracking method to simulate bubble growth under high (up to 45 bar pressure, to obtain the kind of mechanistic information required for an RPI-type approach. In this study, we compare the resulting bubble growth rate curves with predictions made with existing experimental data.

  16. Measurements of mixtures with carbon dioxide under supercritical conditions using commercial high pressure equipment

    Energy Technology Data Exchange (ETDEWEB)

    Andrade, Luciana L.P.R. de; Rutledge, Luis Augusto Medeiros; Moreno, Eesteban L.; Hovell, Ian; Rajagopal, Krishnaswamy [Universidade Federal do Rio de Janeiro (LATCA-EQ-UFRJ), RJ (Brazil). Escola de Quimica. Lab. de Termodinamica e Cinetica Aplicada

    2012-07-01

    There is a growing interest in studying physical properties of binary and multicomponent fluid mixtures with supercritical carbon dioxide (CO{sub 2}) over an extended range of temperature and pressure. The estimation of properties such as density, viscosity, saturation pressure, compressibility, solubility and surface tension of mixtures is important in design, operation and control as well as optimization of chemical processes especially in extractions, separations, catalytic and enzymatic reactions. The phase behaviour of binary and multicomponent mixtures with supercritical CO{sub 2} is also important in the production and refining of petroleum where mixtures of paraffin, naphthene and aromatics with supercritical fluids are often encountered. Petroleum fluids can present a complex phase behaviour in the presence of CO{sub 2}, where two-phase (VLE and LLE) and three phase regions (VLLE) might occur within ranges of supercritical conditions of temperature and pressure. The objective of this study is to develop an experimental methodology for measuring the phase behaviour of mixtures containing CO{sub 2} in supercritical regions, using commercial high-pressure equipment. (author)

  17. Flow instability research on steam generator with straight double-walled heat transfer tube for FBR. Pressure drop under high pressure condition

    International Nuclear Information System (INIS)

    Liu, Wei; Tamai, Hidesada; Yoshida, Hiroyuki; Takase, Kazuyuki; Hayafune, Hiroki; Futagami, Satoshi; Kisohara, Naoyuki

    2008-01-01

    For the Steam Generator (SG) with straight double-walled heat transfer tube that used in sodium cooled Faster Breeder Reactor, flow instability is one of the most important items need researching. As the first step of the research, thermal hydraulics experiments were performed under high pressure condition in JAEA with using a straight tube. Pressure drop, heat transfer coefficients and void fraction data were derived. This paper evaluates the pressure drop data with TRAC-BF1 code. The Pffan's correlation for single phase flow and the Martinelli-Nelson's two-phase flow multiplier are found can be well predicted the present pressure drop data under high pressure condition. (author)

  18. High blood pressure - adults

    Science.gov (United States)

    ... pressure is found. This is called essential hypertension. High blood pressure that is caused by another medical condition or medicine you are taking is called secondary hypertension. Secondary hypertension may be due to: Chronic ...

  19. Re-investigation of the crystal structure of enstatite under high-pressure conditions

    DEFF Research Database (Denmark)

    Periotto, Benedetta; Balic Zunic, Tonci; Nestola, Fabrizio

    2012-01-01

    A synthetic single crystal of pure orthoenstatite (MgSiO3, space group Pbca) has been investigated at high pressure for structural determinations by in situ single-crystal X‑ray diffraction using a diamond-anvil cell. Ten complete intensity data collections were performed up to 9.36 GPa. This study...... with different compositions. The structural evolution determined in this work confirms the high-pressure evolution found previously for other orthopyroxenes and removes some ambiguities originating from the less accurate published data on the MgSiO3 structure at high pressure. The structural compression...

  20. Microstructure and spectroscopy studies on cubic boron nitride synthesized under high-pressure conditions

    International Nuclear Information System (INIS)

    Nistor, L C; Nistor, S V; Dinca, G; Georgeoni, P; Landuyt, J van; Manfredotti, C; Vittone, E

    2002-01-01

    High-resolution electron microscopy (HREM) studies of the microstructure and specific defects in hexagonal boron nitride (h-BN) precursors and cubic boron nitride (c-BN) crystals made under high-pressure high-temperature conditions revealed the presence of half-nanotubes at the edges of the h-BN particles. Their sp 3 bonding tendency could strongly influence the nucleation rates of c-BN. The atomic resolution at extended dislocations was insufficient to allow us to determine the stacking fault energy in the c-BN crystals. Its mean value of 191 pm, 15 mJ m -2 is of the same order of magnitude as that of diamond. High-frequency (94 GHz) electron paramagnetic resonance studies on c-BN single crystals have produced new data on the D1 centres associated with the boron species. Ion-beam-induced luminescence measurements have indicated that c-BN is a very interesting luminescent material, which is characterized by four luminescence bands and exhibits a better resistance to ionizing radiation than CVD diamond

  1. Microstructure and spectroscopy studies on cubic boron nitride synthesized under high-pressure conditions

    Energy Technology Data Exchange (ETDEWEB)

    Nistor, L C [National Institute for Materials Physics, Bucharest (Romania); Nistor, S V [National Institute for Materials Physics, Bucharest (Romania); Dinca, G [Dacia Synthetic Diamonds Factory, Bucharest (Romania); Georgeoni, P [Dacia Synthetic Diamonds Factory, Bucharest (Romania); Landuyt, J van [University of Antwerpen - RUCA, EMAT, Antwerpen (Belgium); Manfredotti, C [Experimental Physics Department, University of Turin, Turin (Italy); Vittone, E [Experimental Physics Department, University of Turin, Turin (Italy)

    2002-11-11

    High-resolution electron microscopy (HREM) studies of the microstructure and specific defects in hexagonal boron nitride (h-BN) precursors and cubic boron nitride (c-BN) crystals made under high-pressure high-temperature conditions revealed the presence of half-nanotubes at the edges of the h-BN particles. Their sp{sup 3} bonding tendency could strongly influence the nucleation rates of c-BN. The atomic resolution at extended dislocations was insufficient to allow us to determine the stacking fault energy in the c-BN crystals. Its mean value of 191 pm, 15 mJ m{sup -2} is of the same order of magnitude as that of diamond. High-frequency (94 GHz) electron paramagnetic resonance studies on c-BN single crystals have produced new data on the D1 centres associated with the boron species. Ion-beam-induced luminescence measurements have indicated that c-BN is a very interesting luminescent material, which is characterized by four luminescence bands and exhibits a better resistance to ionizing radiation than CVD diamond.

  2. Numerical Modeling of MILD Combustion at High Pressure to Predict the Optimal Operating Conditions

    KAUST Repository

    Vanteru, Mahendra Reddy; Roberts, William L.

    2017-01-01

    This Chapter presents numerical simulation on MILD combustion operating at high pressure. Influence of preheat and dilution of oxidizer and operating pressure on stabilization of MILD combustion are presented. Three different preheat temperatures (1100, 1300 and 1500 K) and three different dilution levels (3, 6 and 9% O2) are simulated over an operating pressure variation from 1 atm to 16 atm. A classical jet in hot coflow burner is considered for this study. Total of 45 cases are simulated and analyzed. Essential characteristics of MILD combustion, i.e., maximum temperature (Tmax), temperature rise (ΔT) and temperature distributions, are analyzed. The distribution of emissions OH and CO are also studied and presented. Well-stabilized MILD combustion is observed for all cases except for two cases with high preheated (1500 K). Peak temperature is observed to decrease with increasing operating pressure for a given level of preheat and dilution. OH mass faction is reduced with increasing pressure. The CO emissions show little sensitivity to operating pressure. However, CO mass fraction is slightly higher at 1 atm operating pressure as compared to 4 to 16 atm. Since the residence time of reactants increases as the operating pressure increases, well-stabilized MILD combustion is observed for all highly diluted and low temperature preheat cases (3% O2 and 1100 K).

  3. Numerical Modeling of MILD Combustion at High Pressure to Predict the Optimal Operating Conditions

    KAUST Repository

    Vanteru, Mahendra Reddy

    2017-02-01

    This Chapter presents numerical simulation on MILD combustion operating at high pressure. Influence of preheat and dilution of oxidizer and operating pressure on stabilization of MILD combustion are presented. Three different preheat temperatures (1100, 1300 and 1500 K) and three different dilution levels (3, 6 and 9% O2) are simulated over an operating pressure variation from 1 atm to 16 atm. A classical jet in hot coflow burner is considered for this study. Total of 45 cases are simulated and analyzed. Essential characteristics of MILD combustion, i.e., maximum temperature (Tmax), temperature rise (ΔT) and temperature distributions, are analyzed. The distribution of emissions OH and CO are also studied and presented. Well-stabilized MILD combustion is observed for all cases except for two cases with high preheated (1500 K). Peak temperature is observed to decrease with increasing operating pressure for a given level of preheat and dilution. OH mass faction is reduced with increasing pressure. The CO emissions show little sensitivity to operating pressure. However, CO mass fraction is slightly higher at 1 atm operating pressure as compared to 4 to 16 atm. Since the residence time of reactants increases as the operating pressure increases, well-stabilized MILD combustion is observed for all highly diluted and low temperature preheat cases (3% O2 and 1100 K).

  4. 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.

  5. Characteristics of Syngas Auto-ignition at High Pressure and Low Temperature Conditions with Thermal Inhomogeneities

    KAUST Repository

    Pal, Pinaki; Mansfield, Andrew B.; Wooldridge, Margaret S.; Im, Hong G.

    2015-01-01

    Effects of thermal inhomogeneities on syngas auto-ignition at high-pressure low-temperature conditions, relevant to gas turbine operation, are investigated using detailed one-dimensional numerical simulations. Parametric tests are carried out for a range of thermodynamic conditions (T = 890-1100 K, P = 3-20 atm) and composition (Ф = 0.1, 0.5). Effects of global thermal gradients and localized thermal hot spots are studied. In the presence of a thermal gradient, the propagating reaction front transitions from spontaneous ignition to deflagration mode as the initial mean temperature decreases. The critical mean temperature separating the two distinct auto-ignition modes is computed using a predictive criterion and found to be consistent with front speed and Damkohler number analyses. The hot spot study reveals that compression heating of end-gas mixture by the propagating front is more pronounced at lower mean temperatures, significantly advancing the ignition delay. Moreover, the compression heating effect is dependent on the domain size.

  6. Characteristics of Syngas Auto-ignition at High Pressure and Low Temperature Conditions with Thermal Inhomogeneities

    KAUST Repository

    Pal, Pinaki

    2015-05-31

    Effects of thermal inhomogeneities on syngas auto-ignition at high-pressure low-temperature conditions, relevant to gas turbine operation, are investigated using detailed one-dimensional numerical simulations. Parametric tests are carried out for a range of thermodynamic conditions (T = 890-1100 K, P = 3-20 atm) and composition (Ф = 0.1, 0.5). Effects of global thermal gradients and localized thermal hot spots are studied. In the presence of a thermal gradient, the propagating reaction front transitions from spontaneous ignition to deflagration mode as the initial mean temperature decreases. The critical mean temperature separating the two distinct auto-ignition modes is computed using a predictive criterion and found to be consistent with front speed and Damkohler number analyses. The hot spot study reveals that compression heating of end-gas mixture by the propagating front is more pronounced at lower mean temperatures, significantly advancing the ignition delay. Moreover, the compression heating effect is dependent on the domain size.

  7. Effect of Nb additions on the microstructure, thermal stability and mechanical behavior of high pressure Zr phases under ambient conditions

    International Nuclear Information System (INIS)

    Zhilyaev, A.P.; Sabirov, I.; Gonzalez-Doncel, G.; Molina-Aldareguia, J.; Srinivasarao, B.; Perez-Prado, M.T.

    2011-01-01

    Research highlights: → We analyze the influence of Nb additions on the shear-induced α → ω → β phase transformations in pure Zr by high pressure torsion (HPT). → Nb reduces the transition pressures and increases the transformation kinetics. → High pressure phases are retained under ambient conditions due to the presence of an internal stress. → Post-HPT annealing allows to fabricate bimodal/biphase nanostructures with enhanced mechanical behavior. - Abstract: This paper analyzes the influence of Nb on the shear-induced α → ω → β transformation taking place when processing Zr by high pressure torsion (HPT) under suitable conditions of pressure and shear. With that purpose, pure Zr and Zr-2.5%Nb were processed by HPT at room temperature and at pressures ranging from 0.25 to 6 GPa using 5 anvil turns. Nb causes a further reduction of the transition pressures, which are already lower when applying shear besides pressure. Thus, the transition pressure to the β phase is reduced at least 100 times in the Zr-Nb alloy. Alloying with Nb decreases the grain size of the transformed phases, significantly enhances their thermal stability and increases their UTS and elongation to failure. Selected post-HPT annealing treatments lead to the development of very tough, multiphase Zr and Zr-Nb with bimodal grain size distributions. The retention of the high pressure phases under ambient conditions is explained by the development of a high internal stress during processing. This stress is measured by synchrotron radiation diffraction at HZB-BESSY II. It is proposed that the presence of Nb reduces the internal stress level required for the retention of the high pressure phases.

  8. Safety conditions of using structural steels under high temperature and pressures in hydrogen containing environment

    International Nuclear Information System (INIS)

    Asviyan, M.B.

    1984-01-01

    The method for establishing full-strength conditions was suggested on the base of results of creep-rupture test of tube samples under hydrogen pressure and according to permissible stresses in neutral medium. Applicability of the method was considered taking St3 and 12KhM steels as examples. It was shown that the use of suggested dependences and special efficiency factors enables to forecast endurance limit for the given steel grade and assigned partial hydrogen pressure without labour-intensive test conducting

  9. High Pressure Compression-Molding of α-Cellulose and Effects of Operating Conditions

    Directory of Open Access Journals (Sweden)

    Antoine Rouilly

    2013-05-01

    Full Text Available Commercial α-cellulose was compression-molded to produce 1A dog-bone specimens under various operating conditions without any additive. The resulting agromaterials exhibited a smooth, plastic-like surface, and constituted a suitable target as replacement for plastic materials. Tensile and three-points bending tests were conducted according to ISO standards related to the evaluation of plastic materials. The specimens had strengths comparable to classical petroleum-based thermoplastics. They also exhibited high moduli, which is characteristic of brittle materials. A higher temperature and higher pressure rate produced specimens with higher mechanical properties while low moisture content produced weaker specimens. Generally, the strong specimen had higher specific gravity and lower moisture content. However, some parameters did not follow the general trend e.g., thinner specimen showed much higher Young’s Modulus, although their specific gravity and moisture content remained similar to control, revealing a marked skin-effect which was confirmed by SEM observations.

  10. TURBULENCE SETS THE INITIAL CONDITIONS FOR STAR FORMATION IN HIGH-PRESSURE ENVIRONMENTS

    International Nuclear Information System (INIS)

    Rathborne, J. M.; Contreras, Y.; Longmore, S. N.; Bastian, N.; Jackson, J. M.; Kruijssen, J. M. D.; Alves, J. F.; Bally, J.; Foster, J. B.; Garay, G.; Testi, L.; Walsh, A. J.

    2014-01-01

    Despite the simplicity of theoretical models of supersonically turbulent, isothermal media, their predictions successfully match the observed gas structure and star formation activity within low-pressure (P/k < 10 5 K cm –3 ) molecular clouds in the solar neighborhood. However, it is unknown whether or not these theories extend to clouds in high-pressure (P/k > 10 7 K cm –3 ) environments, like those in the Galaxy's inner 200 pc central molecular zone (CMZ) and in the early universe. Here, we present Atacama Large Millimeter/submillimeter Array 3 mm dust continuum emission within a cloud, G0.253+0.016, which is immersed in the high-pressure environment of the CMZ. While the log-normal shape and dispersion of its column density probability distribution function (PDF) are strikingly similar to those of solar neighborhood clouds, there is one important quantitative difference: its mean column density is one to two orders of magnitude higher. Both the similarity and difference in the PDF compared to those derived from solar neighborhood clouds match predictions of turbulent cloud models given the high-pressure environment of the CMZ. The PDF shows a small deviation from log-normal at high column densities confirming the youth of G0.253+0.016. Its lack of star formation is consistent with the theoretically predicted, environmentally dependent volume density threshold for star formation which is orders of magnitude higher than that derived for solar neighborhood clouds. Our results provide the first empirical evidence that the current theoretical understanding of molecular cloud structure derived from the solar neighborhood also holds in high-pressure environments. We therefore suggest that these theories may be applicable to understand star formation in the early universe

  11. TURBULENCE SETS THE INITIAL CONDITIONS FOR STAR FORMATION IN HIGH-PRESSURE ENVIRONMENTS

    Energy Technology Data Exchange (ETDEWEB)

    Rathborne, J. M.; Contreras, Y. [CSIRO Astronomy and Space Science, P.O. Box 76, Epping NSW, 1710 (Australia); Longmore, S. N.; Bastian, N. [Astrophysics Research Institute, Liverpool John Moores University, 146 Brownlow Hill, Liverpool L3 5RF (United Kingdom); Jackson, J. M. [Institute for Astrophysical Research, Boston University, Boston, MA 02215 (United States); Kruijssen, J. M. D. [Max-Planck Institut fur Astrophysik, Karl-Schwarzschild-Strasse 1, D-85748, Garching (Germany); Alves, J. F. [University of Vienna, Türkenschanzstrasse 17, A-1180 Vienna (Austria); Bally, J. [Center for Astrophysics and Space Astronomy, University of Colorado, UCB 389, Boulder, CO 8030 (United States); Foster, J. B. [Department of Astronomy, Yale University, P.O. Box 208101 New Haven, CT 06520-8101 (United States); Garay, G. [Universidad de Chile, Camino El Observatorio1515, Las Condes, Santiago (Chile); Testi, L. [European Southern Observatory, Karl-Schwarzschild-Strasse 2, D-85748 Garching bei Munchen (Germany); Walsh, A. J., E-mail: Jill.Rathborne@csiro.au [International Centre for Radio Astronomy Research, Curtin University, GPO Box U1987, Perth (Australia)

    2014-11-10

    Despite the simplicity of theoretical models of supersonically turbulent, isothermal media, their predictions successfully match the observed gas structure and star formation activity within low-pressure (P/k < 10{sup 5} K cm{sup –3}) molecular clouds in the solar neighborhood. However, it is unknown whether or not these theories extend to clouds in high-pressure (P/k > 10{sup 7} K cm{sup –3}) environments, like those in the Galaxy's inner 200 pc central molecular zone (CMZ) and in the early universe. Here, we present Atacama Large Millimeter/submillimeter Array 3 mm dust continuum emission within a cloud, G0.253+0.016, which is immersed in the high-pressure environment of the CMZ. While the log-normal shape and dispersion of its column density probability distribution function (PDF) are strikingly similar to those of solar neighborhood clouds, there is one important quantitative difference: its mean column density is one to two orders of magnitude higher. Both the similarity and difference in the PDF compared to those derived from solar neighborhood clouds match predictions of turbulent cloud models given the high-pressure environment of the CMZ. The PDF shows a small deviation from log-normal at high column densities confirming the youth of G0.253+0.016. Its lack of star formation is consistent with the theoretically predicted, environmentally dependent volume density threshold for star formation which is orders of magnitude higher than that derived for solar neighborhood clouds. Our results provide the first empirical evidence that the current theoretical understanding of molecular cloud structure derived from the solar neighborhood also holds in high-pressure environments. We therefore suggest that these theories may be applicable to understand star formation in the early universe.

  12. Experimental Simulation of Methane Hydrate Extraction at High Pressure Conditions: Influence of the Sediment Bed

    Science.gov (United States)

    Agudo, J. R.; Park, J.; Luzi, G.; Williams, M.; Rauh, C.; Wierschem, A.; Delgado, A.

    2017-10-01

    Being a clean alternative to other fossil fuels, Methane Hydrate (MH) is currently considered as one of the most important potential sources for hydrocarbon fuels [1]. In addition, the high energy density of MH and its stability at higher temperatures as compared to LNG (Liquefied Natural Gas) makes MH a potential greener method for energy transportation. At the same time, the low thermodynamic stability of MH strongly questions the future exploitation of gas hydrate deposits, turning its extraction into a possible geohazard [2]. Fluctuations in pressure, temperature, salinity, degree of saturation or sediment bed properties may cause methane gas release from the water lattice. We experimentally study the influence of the sediment bed geometry during formation-dissociation of MH. For this purpose, MH is synthesized within regular substrates in a 93 cm3 high pressure vessel. The regular substrates are triangular and quadratic arrangements of identical glass spheres with a diameter of 2 and 5 mm, respectively. MH formation within regular substrate reduces the possibility of spontaneous nucleation to a unique geometrical configuration. This fact permits us to characterize the kinetics of MH formation-dissociation as a function of the sediment bed geometry. Preliminary experimental results reveal a strong dependence of MH formation on the geometry of the regular substrate. For instance, under the same pressure and temperature, the kinetics of MH production is found to change by a factor 3 solely depending on the substrate symmetry, i.e. triangular or quadratic.

  13. Evaluation of High-Pressure RCS Natural Circulations Under Severe Accident Conditions

    International Nuclear Information System (INIS)

    Lee, Byung Chul; Bang, Young Suk; Suh, Nam Duk

    2006-01-01

    Since TMI-2 accident, the occurrence of severe accident natural circulations inside RCS during entire in-vessel core melt progressions before the reactor vessel breach had been emphasized and tried to clarify its thermal-hydraulic characteristics. As one of consolidated outcomes of these efforts, sophisticated models have been presented to explain the effects of a variety of engineering and phenomenological factors involved during severe accident mitigation on the integrity of RCS pressure boundaries, i.e. reactor pressure vessel(RPV), RCS coolant pipe and steam generator tubes. In general, natural circulation occurs due to density differences, which for single phase flow, is typically generated by temperature differences. Three natural circulation flows can be formed during severe accidents: in-vessel, hot leg countercurrent flow and flow through the coolant loops. Each of these flows may be present during high-pressure transients such as station blackout (SBO) and total loss of feedwater (TLOFW). As a part of research works in order to contribute on the completeness of severe accident management guidance (SAMG) in domestic plants by quantitatively assessing the RCS natural circulations on its integrity, this study presents basic approach for this work and some preliminary results of these efforts with development of appropriately detailed RCS model using MELCOR computer code

  14. Development of Kinetics for Soot Oxidation at High Pressures Under Fuel-Lean Conditions

    Energy Technology Data Exchange (ETDEWEB)

    Lighty, JoAnn [Univ. of Utah, Salt Lake City, UT (United States); Vander Wal, Randy [Pennsylvania State Univ., University Park, PA (United States)

    2014-04-21

    The focus of the proposed research was to develop kinetic models for soot oxidation with the hope of developing a validated, predictive, multi-­scale, combustion model to optimize the design and operation of evolving fuels in advanced engines for transportation applications. The work focused on the relatively unstudied area of the fundamental mechanism for soot oxidation. The objectives include understanding of the kinetics of soot oxidation by O2 under high pressure which require: 1) development of intrinsic kinetics for the surface oxidation, which takes into account the dependence of reactivity upon nanostructure and 2) evolution of nanostructure and its impact upon oxidation rate and 3) inclusion of internal surface area development and possible fragmentation resulting from pore development and /or surface oxidation. These objectives were explored for a variety of pure fuel components and surrogate fuels. This project was a joint effort between the University of Utah (UU) and Pennsylvania State University (Penn State). The work at the UU focuses on experimental studies using a two-­stage burner and a high- pressure thermogravimetric analyzer (TGA). Penn State provided HRTEM images and guidance in the fringe analysis algorithms and parameter quantification for the images. This report focuses on completion done under supplemental funding.

  15. Pressure cylinders under fire condition

    Directory of Open Access Journals (Sweden)

    Jan Hora

    2016-03-01

    Full Text Available The presence of pressure cylinders under fire conditions significantly increases the risk rate for the intervening persons. It is considerably problematic to predict the pressure cylinders behaviour during heat exposition, its destruction progress and possible following explosion of the produced air–gas mixture because pressure cylinders and its environment generate a highly complicated dynamic system during an uncontrolled destruction. The large scale tests carried out by the Pilsen Fire and Rescue Department and the Rapid Response Unit of the Czech Republic Police in October 2012 and in May 2014 in the Military area Brdy and in the area of the former Lachema factory in Kaznějov had several objectives, namely, to record, qualify and quantify some of the aspects of an uncontrolled heat destruction procedure of an exposed pressure cylinder in an enclosed space and to qualify and describe the process of a controlled destruction of a pressure cylinder by shooting through it including basic tactical concepts. The article describes the experiments that were carried out.

  16. EXAFS measurements under high pressure conditions using a combination of a diamond anvil cell and synchrotron radiation

    International Nuclear Information System (INIS)

    Sueno, Shigeho; Nakai, Izumi; Imafuku, Masayuki; Morikawa, Hideki; Kimata, Mitsuyoshi; Ohsumi, Kazumasa; Nomura, Masaharu; Shimomura, Osamu.

    1986-01-01

    EXAFS spectra for Fe, Co, Ni K-edges were successfully measured under high pressure conditions using a combination of a set of normal 1/8 carat diamond anvils, synchrotron radiation and a scintillation counter. A newly developed motor controlled goniometer stage was used for adjusting the position of a miniature diamond anvil cell. On the measurement of Cr and Mn spectra, specially designed thinner diamond anvil was necessary. EXAFS analysis of bis(dimethylglyoximato)nickel(II) at pressures from 1 atm to 5.6 GPa was made. (author)

  17. High burnup fuel onset conditions in dry storage. Prediction of EOL rod internal pressure

    Energy Technology Data Exchange (ETDEWEB)

    Feria, F.; Herranz, L.E.

    2015-07-01

    During dry storage, cladding resistance to failure can be affected by several degrading mechanisms like creep or hydrides radial reorientation. The driving force of these effects is the stress at which the cladding is submitted. The maximum stress in the cladding is determined by the end-of-reactor-life (EOL) rod internal pressure, PEOL, at the maximum temperature attained during dry storage. Thus, PEOL sets the initial conditions of storage for potential time-dependent changes in the cladding. Based on FRAPCON-3.5 calculations, the aim of this work is to analyse the PEOL of a PWR fuel rod irradiated to burnups greater than 60 GWd/tU, where limited information is available. In order to be conservative, demanding irradiation histories have been used with a peak linear power of 44 kW/m. FRAPCON-3.5 results show an increasing exponential trend of PEOL with burnup, from which a simple correlation has been derived. The comparison with experimental data found in the literature confirms the enveloping nature of the predicted curve. Based on that, a conservative prediction of cladding stress in dry storage has been obtained. The comparison with a critical stress threshold related to hydrides embrittlement seems to point out that this issue should not be a concern at burnups below 65 GWd/tU. (Author)

  18. Thermotechnical comparison of possible operation variants for air conditioning system of mine air with high pressure heat exchanger and hydrodistributor

    OpenAIRE

    Korsun, F. O.

    2015-01-01

    Problem. There are vast losses of cold that take place during the transition of cold to deep horizons of shafts by the mine air conditioning system (MASC) with high pressure heat exchanger. Cold is transferred by the recuperative way. Vast losses of cold mean vast losses of electricity to in order to supply it. Any enterprise requires the reduction of electricity consumption. This article gives proposals on how to replace HPHE into hydrodistributor which will considerably reduce cold losses. ...

  19. High Blood Pressure

    Science.gov (United States)

    ... normal blood pressure 140/90 or higher is high blood pressure Between 120 and 139 for the top number, ... prehypertension. Prehypertension means you may end up with high blood pressure, unless you take steps to prevent it. High ...

  20. High Blood Pressure Facts

    Science.gov (United States)

    ... Stroke Heart Disease Cholesterol Salt Million Hearts® WISEWOMAN High Blood Pressure Facts Recommend on Facebook Tweet Share Compartir On ... Top of Page CDC Fact Sheets Related to High Blood Pressure High Blood Pressure Pulmonary Hypertension Heart Disease Signs ...

  1. High Blood Pressure (Hypertension)

    Science.gov (United States)

    ... Print Page Text Size: A A A Listen High Blood Pressure (Hypertension) Nearly 1 in 3 American adults has ... weight. How Will I Know if I Have High Blood Pressure? High blood pressure is a silent problem — you ...

  2. Design of experimental setup for supercritical CO2 jet under high ambient pressure conditions

    Science.gov (United States)

    Shi, Huaizhong; Li, Gensheng; He, Zhenguo; Wang, Haizhu; Zhang, Shikun

    2016-12-01

    With the commercial extraction of hydrocarbons in shale and tight reservoirs, efficient methods are needed to accelerate developing process. Supercritical CO2 (SC-CO2) jet has been considered as a potential way due to its unique fluid properties. In this article, a new setup is designed for laboratory experiment to research the SC-CO2 jet's characteristics in different jet temperatures, pressures, standoff distances, ambient pressures, etc. The setup is composed of five modules, including SC-CO2 generation system, pure SC-CO2 jet system, abrasive SC-CO2 jet system, CO2 recovery system, and data acquisition system. Now, a series of rock perforating (or case cutting) experiments have been successfully conducted using the setup about pure and abrasive SC-CO2 jet, and the results have proven the great perforating efficiency of SC-CO2 jet and the applications of this setup.

  3. Characterization of metal powder based rapid prototyping components under aluminium high pressure die casting process conditions

    CSIR Research Space (South Africa)

    Pereira, MFVT

    2009-11-01

    Full Text Available periodic inspections, monitoring crack formation and evidence of surface washout. At the end of the thermal tests, mechanical strength and hardness tests were performed to assess toughness and core resistance variations in relation to the initial conditions...

  4. 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 ...

  5. Pressure measurements and high speed visualizations of the cavitation phenomena at deep part load condition in a Francis turbine

    International Nuclear Information System (INIS)

    Yamamoto, K; Müller, A; Favrel, A; Landry, C; Avellan, F

    2014-01-01

    In a hydraulic power plant, it is essential to provide a reliable, sustainable and flexible energy supply. In recent years, in order to cover the variations of the renewable electricity production, hydraulic power plants are demanded to operate with more extended operating range. Under these off-design conditions, a hydraulic turbine is subject to cavitating swirl flow at the runner outlet. It is well-known that the helically/symmetrically shaped cavitation develops at the runner outlet in part load/full load condition, and it gives severe damage to the hydraulic systems under certain conditions. Although there have been many studies about partial and full load conditions, contributions reporting the deep part load condition are limited, and the cavitation behaviour at this condition is not yet understood. This study aims to unveil the cavitation phenomena at deep part load condition by high speed visualizations focusing on the draft tube cone as well as the runner blade channel, and pressure fluctuations associated with the phenomena were also investigated

  6. High Pressure Biomass Gasification

    Energy Technology Data Exchange (ETDEWEB)

    Agrawal, Pradeep K [Georgia Tech Research Corporation, Atlanta, GA (United States)

    2016-07-29

    According to the Billion Ton Report, the U.S. has a large supply of biomass available that can supplement fossil fuels for producing chemicals and transportation fuels. Agricultural waste, forest residue, and energy crops offer potential benefits: renewable feedstock, zero to low CO2 emissions depending on the specific source, and domestic supply availability. Biomass can be converted into chemicals and fuels using one of several approaches: (i) biological platform converts corn into ethanol by using depolymerization of cellulose to form sugars followed by fermentation, (ii) low-temperature pyrolysis to obtain bio-oils which must be treated to reduce oxygen content via HDO hydrodeoxygenation), and (iii) high temperature pyrolysis to produce syngas (CO + H2). This last approach consists of producing syngas using the thermal platform which can be used to produce a variety of chemicals and fuels. The goal of this project was to develop an improved understanding of the gasification of biomass at high pressure conditions and how various gasification parameters might affect the gasification behavior. Since most downstream applications of synags conversion (e.g., alcohol synthesis, Fischer-Tropsch synthesis etc) involve utilizing high pressure catalytic processes, there is an interest in carrying out the biomass gasification at high pressure which can potentially reduce the gasifier size and subsequent downstream cleaning processes. It is traditionally accepted that high pressure should increase the gasification rates (kinetic effect). There is also precedence from coal gasification literature from the 1970s that high pressure gasification would be a beneficial route to consider. Traditional approach of using thermogravimetric analyzer (TGA) or high-pressure themogravimetric analyzer (PTGA) worked well in understanding the gasification kinetics of coal gasification which was useful in designing high pressure coal gasification processes. However

  7. Numerical Simulations of Evaporating Sprays in High Pressure and Temperature Operating Conditions (Engine Combustion Network [ECN])

    Science.gov (United States)

    2014-05-01

    temperature effect in nonreacting and reacting diesel sprays using a novel injector , and imaging diagnostics for liquid phase penetration, light-off...ambient conditions. A single hole, modern common rail injector with an injector diameter of 90 µ (Bosch CRIN 2.4) is used at typical diesel injection...Temperature (K) 363 Ambient temperature (K) 900 Nozzle Diameter (mm) 0.09 Ambient density (kg/m3) 22.8 Injection Duration (ms) 1.5 Number of injector holes

  8. Carbonation by fluid-rock interactions at high-pressure conditions: Implications for carbon cycling in subduction zones

    Science.gov (United States)

    Piccoli, Francesca; Vitale Brovarone, Alberto; Beyssac, Olivier; Martinez, Isabelle; Ague, Jay J.; Chaduteau, Carine

    2016-07-01

    Carbonate-bearing lithologies are the main carbon carrier into subduction zones. Their evolution during metamorphism largely controls the fate of carbon, regulating its fluxes between shallow and deep reservoirs. Recent estimates predict that almost all subducted carbon is transferred into the crust and lithospheric mantle during subduction metamorphism via decarbonation and dissolution reactions at high-pressure conditions. Here we report the occurrence of eclogite-facies marbles associated with metasomatic systems in Alpine Corsica (France). The occurrence of these marbles along major fluid-conduits as well as textural, geochemical and isotopic data indicating fluid-mineral reactions are compelling evidence for the precipitation of these carbonate-rich assemblages from carbonic fluids during metamorphism. The discovery of metasomatic marbles brings new insights into the fate of carbonic fluids formed in subducting slabs. We infer that rock carbonation can occur at high-pressure conditions by either vein-injection or chemical replacement mechanisms. This indicates that carbonic fluids produced by decarbonation reactions and carbonate dissolution may not be directly transferred to the mantle wedge, but can interact with slab and mantle-forming rocks. Rock-carbonation by fluid-rock interactions may have an important impact on the residence time of carbon and oxygen in subduction zones and lithospheric mantle reservoirs as well as carbonate isotopic signatures in subduction zones. Furthermore, carbonation may modulate the emission of CO2 at volcanic arcs over geological time scales.

  9. Sorption activity investigation of ultrafine powders of high temperature melting point compounds in atmospheric pressure conditions

    International Nuclear Information System (INIS)

    Rudneva, V.V.

    2006-01-01

    A study is made in saturation with gas in the air for ultradispersed chromium carbonitride and boride powders synthesized in a nitrogen plasma jet according to three variants: from elements, from oxides, from chromium trichloride. It is established that in the air on temperature increasing the powders adsorb considerable amounts of oxygen and water vapor. This results in surface oxidation of powder particles and a loss in specific combination of properties. Preliminary vacuum heat treatment is shown to decrease sharply the rate of atmospheric gas adsorption. The quantity of adsorbed gases is dependent on a carbon monoxide concentration in a particle surface layer and the availability of adsorption centers. The number of such centers in the layer can be controlled by vacuum heat treatment conditions. The interaction of the powders with atmospheric gases is concluded to be of adsorption-diffusion nature [ru

  10. High blood pressure - children

    Science.gov (United States)

    ... this page: //medlineplus.gov/ency/article/007696.htm High blood pressure - children To use the sharing features on this page, please enable JavaScript. High blood pressure (hypertension) is an increase in the force of ...

  11. Preventing High Blood Pressure

    Science.gov (United States)

    ... Heart Disease Cholesterol Salt Million Hearts® WISEWOMAN Preventing High Blood Pressure: Healthy Living Habits Recommend on Facebook Tweet Share ... meal and snack options can help you avoid high blood pressure and its complications. Be sure to eat plenty ...

  12. High blood pressure - infants

    Science.gov (United States)

    ... this page: //medlineplus.gov/ency/article/007329.htm High blood pressure - infants To use the sharing features on this page, please enable JavaScript. High blood pressure (hypertension) is an increase in the force of ...

  13. High blood pressure medications

    Science.gov (United States)

    ... this page: //medlineplus.gov/ency/article/007484.htm High blood pressure medicines To use the sharing features on this page, please enable JavaScript. Treating high blood pressure will help prevent problems such as heart disease, ...

  14. High-pressure microbiology

    National Research Council Canada - National Science Library

    Michiels, Chris; Bartlett, Douglas Hoyt; Aertsen, Abram

    2008-01-01

    ... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1. High Hydrostatic Pressure Effects in the Biosphere: from Molecules to Microbiology * Filip Meersman and Karel Heremans . . . . . . . . . . . . 2. Effects...

  15. High-pressure apparatus

    NARCIS (Netherlands)

    Schepdael, van L.J.M.; Bartels, P.V.; Berg, van den R.W.

    1999-01-01

    The invention relates to a high-pressure device (1) having a cylindrical high-pressure vessel (3) and prestressing means in order to exert an axial pressure on the vessel. The vessel (3) can have been formed from a number of layers of composite material, such as glass, carbon or aramide fibers which

  16. Multiple-pass high-pressure homogenization of milk for the development of pasteurization-like processing conditions.

    Science.gov (United States)

    Ruiz-Espinosa, H; Amador-Espejo, G G; Barcenas-Pozos, M E; Angulo-Guerrero, J O; Garcia, H S; Welti-Chanes, J

    2013-02-01

    Multiple-pass ultrahigh pressure homogenization (UHPH) was used for reducing microbial population of both indigenous spoilage microflora in whole raw milk and a baroresistant pathogen (Staphylococcus aureus) inoculated in whole sterile milk to define pasteurization-like processing conditions. Response surface methodology was followed and multiple response optimization of UHPH operating pressure (OP) (100, 175, 250 MPa) and number of passes (N) (1-5) was conducted through overlaid contour plot analysis. Increasing OP and N had a significant effect (P pasteurization. Multiple-pass UHPH optimized conditions might help in producing safe milk without the detrimental effects associated with thermal pasteurization. © 2012 The Society for Applied Microbiology.

  17. Frictional property of rocks in the Izu-Bonin-Mariana Forearc under high temperature and pressure conditions

    Science.gov (United States)

    Hyodo, G.; Takahashi, M.; Saito, S.; Hirose, T.

    2014-12-01

    The Kanto region in central Japan lies atop of three tectonic plates: the North American Plate, the Pacific Plate, and the Philippine Sea Plate. The collision and subduction of the Izu-Bonin-Mariana (IBM) arc on the Philippine Sea Plate into the Kanto region results in occurring the different type of earthquakes, including seismic slip (e.g., the Kanto earthquake) and aseismic creep (i.e., slow earthquakes around the Boso peninsula). The seismic and aseismic slip seems to generate side by side at almost same depth (probably nearly same P-T conditions). This study focus on frictional property of incoming materials to be subducted into the Kanto region, in order to examine a hypothesis that the different types of slips arise from different input materials. Thus, we have performed friction experiments on rocks that constitute the IBM forearc using a high P-T gas medium apparatus at AIST. We sampled five rocks (marl, boninite, andesite, sheared serpentinite and serpentinized dunite) recovered from the IBM forearc by Leg 125, Ocean Drilling Program (ODP Site 784, 786). The rocks were crushed and sieved into 10˜50 µm in grain size. Experiments were conducted at temperature of 300○C, confining pressure of 156 MPa, pore pressure of 60 MPa and axial displacement rates of 0.1 and 1 µm/s. For marl, andesite and boninite, a periodic stick-slip behavior appears at 1 µm/s. Rise time of the stick-slip behaviors are quite long (3.1, 9.9 and 14.2 sec, for marl, andesite and boninite, respectively). We called such events as a "slow stick-slip". Similar slow stick-slip behaviors were observed in previous studies (Noda and Shimamoto, 2010; Okazaki, 2013; Kaproth and Marone, 2013), but this is first time to recognize this characteristic slip behavior in sedimentary and igneous rocks. Although it is difficult to discuss the diverse slip behaviors observed at the Kanto region based on our limited experimental results, we will examine the conditions where the transition between

  18. Stability of Hydrogen-Bonded Supramolecular Architecture under High Pressure Conditions: Pressure-Induced Amorphization in Melamine-Boric Acid Adduct

    International Nuclear Information System (INIS)

    Wang, K.; Duan, D.; Wang, R.; Lin, A.; Cui, Q.; Liu, B.; Cui, T.; Zou, B.; Zhang, X.

    2009-01-01

    The effects of high pressure on the structural stability of the melamine-boric acid adduct (C3N6H6 2H3BO3, M 2B), a three-dimensional hydrogen-bonded supramolecular architecture, were studied by in situ synchrotron X-ray diffraction (XRD) and Raman spectroscopy. M 2B exhibited a high compressibility and a strong anisotropic compression, which can be explained by the layerlike crystal packing. Furthermore, evolution of XRD patterns and Raman spectra indicated that the M 2B crystal undergoes a reversible pressure-induced amorphization (PIA) at 18 GPa. The mechanism for the PIA was attributed to the competition between close packing and long-range order. Ab initio calculations were also performed to account for the behavior of hydrogen bonding under high pressure.

  19. High Blood Pressure (Hypertension)

    Science.gov (United States)

    ... other risk factors, like diabetes, you may need treatment. How does high blood pressure affect pregnant women? A few women will get ... HIV, Birth Control Heart Health for Women Pregnancy Menopause More Women's Health ... High Blood Pressure--Medicines to Help You Women and Diabetes Heart ...

  20. High-pressure crystallography

    Science.gov (United States)

    Katrusiak, A.

    2008-01-01

    The history and development of high-pressure crystallography are briefly described and examples of structural transformations in compressed compounds are given. The review is focused on the diamond-anvil cell, celebrating its 50th anniversary this year, the principles of its operation and the impact it has had on high-pressure X-ray diffraction.

  1. Speciation of High-Pressure Carbon-Saturated COH Fluids at Buffered fO2 Conditions: An Experimental Approach

    Science.gov (United States)

    Tumiati, S.; Tiraboschi, C.; Recchia, S.; Poli, S.

    2014-12-01

    The quantitative assessment of species in COH fluids is crucial in modelling mantle processes. For instance, H2O/CO2 ratio in the fluid phase influences the location of the solidus and of carbonation/decarbonation reactions in peridotitic systems . In the scientific literature, the speciation of COH fluids has been generally assumed on the basis of thermodynamic calculations using equations of state of simple H2O-non-polar gas systems (e.g., H2O-CO2-CH4). Only few authors dealt with the experimental determination of high-pressure COH fluid species at different conditions, using diverse experimental and analytical approaches (e.g., piston cylinder+capsule-piercing+gas-chromatography/mass-spectrometry; cold-seal+silica glass capsules+Raman). We performed experiments on COH fluids using a capsule-piercing device coupled with a quadrupole mass spectrometry. This type of analyzer ensures superior performances in terms of selectivity of molecules to be detected, high acquisition rates and extended linear response range. Experiments were carried out in a rocking piston cylinder apparatus at pressure of 1 GPa and temperatures from 800 to 900°C. Carbon-saturated fluids were generated through the addition of oxalic acid dihydrate and graphite. Single/double capsules and different packing materials (BN and MgO) were used to evaluate the divergence from the thermodynamic speciation model. Moreover, to assess the effect of solutes on COH fluid speciation we also performed a set of experiments adding synthetic forsterite to the charge. To determine the speciation we assembled a capsule-piercing device that allows to puncture the capsule in a gas-tight vessel at 80°C. The extraction Teflon vessel is composed of a base part, where the capsule is allocated on a steel support, and a top part where a steel drill is mounted. To release the quenched fluids from the capsule, the base part of vessel is hand-tighten to the top part, allowing the steel pointer to pierce the capsule. The

  2. High-pressure behavior and crystal–fluid interaction under extreme conditions in paulingite [PAU-topology

    Czech Academy of Sciences Publication Activity Database

    Gatta, G. D.; Scheidl, K. S.; Pippinger, T.; Skála, Roman; Lee, J.; Miletich, R.

    2015-01-01

    Roč. 206, April (2015), s. 34-41 ISSN 1387-1811 Institutional support: RVO:67985831 Keywords : paulingite * high pressure * X-ray diffraction * compressibility * crystal–fluid interaction Subject RIV: DB - Geology ; Mineralogy Impact factor: 3.349, year: 2015

  3. High Blood Pressure

    Science.gov (United States)

    ... kidney disease, diabetes, or metabolic syndrome Read less Unhealthy lifestyle habits Unhealthy lifestyle habits can increase the risk of high blood pressure. These habits include: Unhealthy eating patterns, such as eating too much sodium ...

  4. High Blood Pressure

    Science.gov (United States)

    ... factors Diabetes High blood pressure Family history Obesity Race/ethnicity Full list of causes and risk factors ... give Give monthly Memorials and tributes Donate a car Donate gently used items Stock donation Workplace giving ...

  5. High pressure phase transformations revisited.

    Science.gov (United States)

    Levitas, Valery I

    2018-04-25

    High pressure phase transformations play an important role in the search for new materials and material synthesis, as well as in geophysics. However, they are poorly characterized, and phase transformation pressure and pressure hysteresis vary drastically in experiments of different researchers, with different pressure transmitting media, and with different material suppliers. Here we review the current state, challenges in studying phase transformations under high pressure, and the possible ways in overcoming the challenges. This field is critically compared with fields of phase transformations under normal pressure in steels and shape memory alloys, as well as plastic deformation of materials. The main reason for the above mentioned discrepancy is the lack of understanding that there is a fundamental difference between pressure-induced transformations under hydrostatic conditions, stress-induced transformations under nonhydrostatic conditions below yield, and strain-induced transformations during plastic flow. Each of these types of transformations has different mechanisms and requires a completely different thermodynamic and kinetic description and experimental characterization. In comparison with other fields the following challenges are indicated for high pressure phase transformation: (a) initial and evolving microstructure is not included in characterization of transformations; (b) continuum theory is poorly developed; (c) heterogeneous stress and strain fields in experiments are not determined, which leads to confusing material transformational properties with a system behavior. Some ways to advance the field of high pressure phase transformations are suggested. The key points are: (a) to take into account plastic deformations and microstructure evolution during transformations; (b) to formulate phase transformation criteria and kinetic equations in terms of stress and plastic strain tensors (instead of pressure alone); (c) to develop multiscale continuum

  6. High pressure phase transformations revisited

    Science.gov (United States)

    Levitas, Valery I.

    2018-04-01

    High pressure phase transformations play an important role in the search for new materials and material synthesis, as well as in geophysics. However, they are poorly characterized, and phase transformation pressure and pressure hysteresis vary drastically in experiments of different researchers, with different pressure transmitting media, and with different material suppliers. Here we review the current state, challenges in studying phase transformations under high pressure, and the possible ways in overcoming the challenges. This field is critically compared with fields of phase transformations under normal pressure in steels and shape memory alloys, as well as plastic deformation of materials. The main reason for the above mentioned discrepancy is the lack of understanding that there is a fundamental difference between pressure-induced transformations under hydrostatic conditions, stress-induced transformations under nonhydrostatic conditions below yield, and strain-induced transformations during plastic flow. Each of these types of transformations has different mechanisms and requires a completely different thermodynamic and kinetic description and experimental characterization. In comparison with other fields the following challenges are indicated for high pressure phase transformation: (a) initial and evolving microstructure is not included in characterization of transformations; (b) continuum theory is poorly developed; (c) heterogeneous stress and strain fields in experiments are not determined, which leads to confusing material transformational properties with a system behavior. Some ways to advance the field of high pressure phase transformations are suggested. The key points are: (a) to take into account plastic deformations and microstructure evolution during transformations; (b) to formulate phase transformation criteria and kinetic equations in terms of stress and plastic strain tensors (instead of pressure alone); (c) to develop multiscale continuum

  7. New problems in solid-state chemistry solved by high pressure conditions: an exciting perspective for preparing new materials

    OpenAIRE

    Demazeau , Gérard

    1988-01-01

    International audience; The high-pressure technique is an efficient tool in solid-state chemistry for preparing new materials of low stability or metastable character. During the last 20 years, this technique has been used and developed especially in three principal areas : synthesis of new materials, either for a better basic approach of scientific problems or for industrial applications studies of structural transformations in situ evolution of some physical properties of materials under pr...

  8. High-pressure tritium

    International Nuclear Information System (INIS)

    Coffin, D.O.

    1976-01-01

    Some solutions to problems of compressing and containing tritium gas to 200 MPa at 700 0 K are discussed. The principal emphasis is on commercial compressors and high-pressure equipment that can be easily modified by the researcher for safe use with tritium. Experience with metal bellows and diaphragm compressors has been favorable. Selection of materials, fittings, and gauges for high-pressure tritium work is also reviewed briefly

  9. Thermochemical micro imprinting of single-crystal diamond surface using a nickel mold under high-pressure conditions

    Energy Technology Data Exchange (ETDEWEB)

    Imoto, Yuji; Yan, Jiwang, E-mail: yan@mech.keio.ac.jp

    2017-05-15

    Graphical abstract: A Ni mold and thermochemically imprinted microstructures on diamond. - Highlights: • A thermochemical method for micro machining/patterning of diamond is proposed. • Various kinds of microstructures were imprinted on diamond using a Ni mold. • A graphite layer is formed during imprinting which can be removed by acid. • The processing depth depends strongly on pressure and temperature. - Abstract: Single-crystal diamond is an important material for cutting tools, micro electro mechanical systems, optical devices, and semiconductor substrates. However, the techniques for producing microstructures on diamond surface with high efficiency and accuracy have not been established. This paper proposes a thermochemical imprinting method for transferring microstructures from a nickel (Ni) mold onto single-crystal diamond surface. The Ni mold was micro-structured by a nanoindenter and then pressed against the diamond surface under high temperature and pressure in argon atmosphere. Results show that microstructures on the Ni mold were successfully transferred onto the diamond surface, and their depth increased with both pressure and temperature. Laser micro-Raman spectroscopy, transmission electron microscopy (TEM) and electron energy loss spectroscopy (EELS) analyses indicate that a graphite layer was formed over the contact area between diamond and Ni during pressing, and after washing by a mixed acid, the graphite layer could be completely removed. This study demonstrated the feasibility of a cost-efficient fabrication method for large-area microstructures on single-crystal diamond.

  10. Chaotic oscillations in a low pressure two-phase natural circulation loop under low power and high inlet subcooling conditions

    International Nuclear Information System (INIS)

    Wu, C.Y.; Wang, S.B.; Pan, C.

    1996-01-01

    The oscillation characteristics of a low pressure two-phase natural circulation loop have been investigated experimentally in this study. Experimental results indicate that the characteristics of the thermal hydraulic oscillations can be periodic, with 2-5 fundamental frequencies, or chaotic, depending on the heating power and inlet subcooling. The number of fundamental frequencies of oscillation increases if the inlet subcooling is increased at a given heating power or the heating power is decreased at a given inlet subcooling; chaotic oscillations appear if the inlet subcooling is further increased and/or the heating power is further decreased. A map of the oscillation characteristics is thus established. The change in oscillation characteristics is evident from the time evolution and power spectrum of a thermal hydraulic parameter and the phase portraits of two thermal hydraulic parameters. These results reveal that a strange attractor exists in a low pressure two-phase natural circulation loop with low power and very high inlet subcooling. (orig.)

  11. Effects of storage conditions before or after high-hydrostatic pressure on inactivation of Vibrio parahaemolyticus and Vibrio vulnificus in oysters

    Science.gov (United States)

    The effect of storage conditions on subsequent high-hydrostatic pressure (HHP) inactivation of V. parahaemolyticus and V. vulnificus in oyster meat was investigated. Live oysters were inoculated with V. parahaemolyticus or V. vulnificus to ca. 7-8 log MPN/g by feeding and stored at different conditi...

  12. A study on variations of the low cycle fatigue life of a high pressure turbine nozzle caused by inlet temperature profiles and installation conditions

    Energy Technology Data Exchange (ETDEWEB)

    Huh, Jae Sung; Kang, Young Seok; Rhee, Dong Ho [Aero-propulsion Research Office, Korea Aerospace Research Institute, Daejeon (Korea, Republic of); Seo, Do Young [School of Mechanical and Aerospace Engineering, Pusan National University, Busan (Korea, Republic of)

    2015-11-15

    High pressure components of a gas turbine engine must operate for a long life under severe conditions in order to maximize the performance and minimize the maintenance cost. Enhanced cooling design, thermal barrier coating techniques, and nickel-base superalloys have been applied for overcoming them and furthermore, material modeling, finite element analysis, statistical techniques, and etc. in design stage have been utilized widely. This article aims to evaluate the effects on the low cycle fatigue life of the high pressure turbine nozzle caused by different turbine inlet temperature profiles and installation conditions and to investigate the most favorable operating condition to the turbine nozzle. To achieve it, the structural analysis, which utilized the results of conjugate heat transfer analysis as loading boundary conditions, was performed and its results were the input for the assessment of low cycle fatigue life at several critical zones.

  13. A Study on Variations of the Low Cycle Fatigue Life of a High Pressure Turbine Nozzle Caused by Inlet Temperature Profiles and Installation Conditions

    Energy Technology Data Exchange (ETDEWEB)

    Hur, Jae Sung; Kang, Young Seok; Rhee, Dong Ho [Korea Aerospace Research Institute, Daejeon (Korea, Republic of); Seo, Do Young [Pusan National Univ., Busan (Korea, Republic of)

    2015-11-15

    High pressure components of a gas turbine engine must operate for a long life under severe conditions in order to maximize the performance and minimize the maintenance cost. Enhanced cooling design, thermal barrier coating techniques, and nickel-base superalloys have been applied for overcoming them and furthermore, material modeling, finite element analysis, statistical techniques, and etc. in design stage have been utilized widely. This article aims to evaluate the effects on the low cycle fatigue life of the high pressure turbine nozzle caused by different turbine inlet temperature profiles and installation conditions and to investigate the most favorable operating condition to the turbine nozzle. To achieve it, the structural analysis, which utilized the results of conjugate heat transfer analysis as loading boundary conditions, was performed and its results were the input for the assessment of low cycle fatigue life at several critical zones.

  14. Deuterium high pressure target

    International Nuclear Information System (INIS)

    Perevozchikov, V.V.; Yukhimchuk, A.A.; Vinogradov, Yu.I.

    2001-01-01

    The design of the deuterium high-pressure target is presented. The target having volume of 76 cm 3 serves to provide the experimental research of muon catalyzed fusion reactions in ultra-pure deuterium in the temperature range 80-800 K under pressures of up to 150 MPa. The operation of the main systems of the target is described: generation and purification of deuterium gas, refrigeration, heating, evacuation, automated control system and data collection system

  15. Field-emitting Townsend regime of surface dielectric barrier discharges emerging at high pressure up to supercritical conditions

    International Nuclear Information System (INIS)

    Pai, David Z; Stauss, Sven; Terashima, Kazuo

    2015-01-01

    Surface dielectric barrier discharges (DBDs) in CO 2 from atmospheric pressure up to supercritical conditions generated using 10 kHz ac excitation are investigated experimentally. Using current–voltage and charge–voltage measurements, imaging, optical emission spectroscopy, and spontaneous Raman spectroscopy, we identify and characterize a field-emitting Townsend discharge regime that emerges above 0.7 MPa. An electrical model enables the calculation of the discharge-induced capacitances of the plasma and the dielectric, as well as the space-averaged values of the surface potential and the potential drop across the discharge. The space-averaged Laplacian field is accounted for in the circuit model by including the capacitance due to the fringe electric field from the electrode edge. The electrical characteristics are demonstrated to fit the description of atmospheric-pressure Townsend DBDs (Naudé et al 2005 J. Phys. D: Appl. Phys. 38 530–8), i.e. self-sustained DBDs with minimal space-charge effects. The purely continuum emission spectrum is due to electron–neutral bremsstrahlung corresponding to an average electron temperature of 2600 K. Raman spectra of CO 2 near the critical point demonstrate that the average gas temperature increases by less than 1 K. (paper)

  16. The accuracy of the crystal chemical parameters at high-pressure conditions from single-crystal X-ray diffraction in diamond-anvil cell

    DEFF Research Database (Denmark)

    Periotto, Benedetta

    -ray instruments. At the same time, the high-pressure experiments have benefited by the strong improvements on the high-pressure devices, in particular the diamond-anvil cell (DAC). The aim of this research project is to assess the quality of the data obtained by means of the single-crystal X-ray diffraction...... technique through the study of different mineral phases. The procedure for setting up an experiment under high-pressure conditions, using a single crystal as sample held within a DAC, are presented here with all the details of the in situ measurements at high-pressure conditions. The research project...... started with a comparison between two different DACs, in order to define the capabilities of one of the most common types of pressure device, the ETH-type DAC. Application examples of data quality analysis have been conducted on pyroxenes (NaInSi2O6, orthoenstatite MgSiO3 and LiCrSi2O6), which...

  17. Fascination at high pressures

    International Nuclear Information System (INIS)

    Chidambaram, R.

    1992-01-01

    Research at high pressures has developed into an interdisciplinary area which has important implications for and applications in the areas of physics, chemistry, materials sciences, planetary sciences, biology, engineering sciences and technology. The state of-the-art in this field is reviewed and future directions are indicated. (M.G.B.)

  18. Reverse spin-crossover and high-pressure kinetics of the heme iron center relevant for the operation of heme proteins under deep-sea conditions.

    Science.gov (United States)

    Troeppner, Oliver; Lippert, Rainer; Shubina, Tatyana E; Zahl, Achim; Jux, Norbert; Ivanović-Burmazović, Ivana

    2014-10-20

    By design of a heme model complex with a binding pocket of appropriate size and flexibility, and by elucidating its kinetics and thermodynamics under elevated pressures, some of the pressure effects are demonstrated relevant for operation of heme-proteins under deep-sea conditions. Opposite from classical paradigms of the spin-crossover and reaction kinetics, a pressure increase can cause deceleration of the small-molecule binding to the vacant coordination site of the heme-center in a confined space and stabilize a high-spin state of its Fe center. This reverse high-pressure behavior can be achieved only if the volume changes related to the conformational transformation of the cavity can offset the volume changes caused by the substrate binding. It is speculated that based on these criteria nature could make a selection of structures of heme pockets that assist in reducing metabolic activity and enzymatic side reactions under extreme pressure conditions. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  19. Axial gas transport and loss of pressure after ballooning rupture of high burn-up fuel rods subjected to LOCA conditions

    International Nuclear Information System (INIS)

    Wiesenack, Wolfgang; Oberlaender, Barbara; Kekkonen, Laura

    2008-01-01

    The OECD Halden Reactor Project has implemented integral in-pile tests on issues related to fuel behaviour under LOCA conditions. In this test series, the interaction of bonded fuel and cladding, the behaviour of fragmented fuel around the ballooning area, and the axial gas communication in high burn-up rods as affected by gap closure and fuel-clad bonding are of major interest for the investigations. In the Halden reactor tests, the decay heat is simulated by a low level of nuclear heating, in contrast to the heating conditions implemented in hot laboratory set-ups, and the thermal expansion of fuel and cladding relative to each other is more similar to the real event. The paper deals with observations regarding the loss of rod pressure following the rupture of the cladding. In the majority of the tests conducted so far, the rod pressure dropped practically instantaneously as a consequence of ballooning rupture, while one test showed a remarkably slow pressure loss. The slow loss of pressure in this test was analysed, showing that the 'hydraulic diameter' of the rod over an un-distended upper part was about 30 - 35 μm which is typical of high burn-up fuel at hot-standby conditions. The 'plug' of fuel restricts the gas flow from the plenum through the fuel column and thus limits the availability of high pressure gas for driving the ballooning. This observation is relevant for the analysis of the behaviour of a full length fuel rod under LOCA conditions since restricted gas flow may influence bundle blockage and the number of failures. (authors)

  20. Investigation into the effects of operating conditions and design parameters on the creep life of high pressure turbine blades in a stationary gas turbine engine

    OpenAIRE

    Eshati, Samir; Abu, Abdullahi; Laskaridis, Panagiotis; Haslam, Anthony

    2011-01-01

    A physics–based model is used to investigate the relationship between operating conditions and design parameters on the creep life of a stationary gas turbine high pressure turbine (HPT) blade. A performance model is used to size the blade and to determine its stresses. The effects of radial temperature distortion, turbine inlet temperature, ambient temperature and compressor degradation on creep life are then examined. The results show variations in creep life and failure locat...

  1. The influence of boron on the crystal structure and properties of mullite. Investigations at ambient, high-pressure, and high-temperature conditions

    Energy Technology Data Exchange (ETDEWEB)

    Luehrs, Hanna

    2013-11-21

    Mullite is one of the most important synthetic compounds for advanced structural and functional ceramic materials. The crystal structure of mullite with the composition Al{sub 2}[Al{sub 2+2x}Si{sub 2-2x}]O{sub 10-x} can incorporate a large variety of foreign cations, including (amongst others) significant amounts of boron. However, no chemical or crystal structure analyses of boron-mullites (B-mullites) were available prior to this work, thus representing the key aspects of this thesis. Furthermore, the influence of boron on selected properties of mullite under ambient, high-temperature, and high-pressure conditions are addressed. Starting from a 3:2 mullite composition (Al{sub 4.5}Si{sub 1.5}O{sub 9.75}), the initial hypothesis for this study was a 1:1 isomorphous replacement of silicon by boron according to the coupled substitution mechanism: 2 Si{sup 4+} + O{sup 2-} → 2 B{sup 3+} + □. Based on a series of compounds synthesized from sol-gel derived precursors at ambient pressure and 1200 C, the formation conditions and physical properties of B-mullites were investigated. The formation temperature for B-mullites decreases with increasing boron-content, as revealed by thermal analyses. An anisotropic development of lattice parameters is observed: Whereas lattice parameters a and b only exhibit minor changes, a linear relationship between lattice parameter c and the amount of boron in the crystal structure was established, on the basis of prompt gamma activation analyses (PGAA) and Rietveld refinements. According to this relationship about 15% of the silicon in mullite can be replaced by boron yielding single-phase B-mullite. B-mullites with significantly higher (∝ factor 3) boron-contents in the mullite structure were also observed but the respective samples contain alumina impurities. Fundamental new details regarding the response of B-mullite to high-temperature and highpressure are presented in this thesis. On the one hand, long-term thermal stability at

  2. Improvement of Coenzyme Q10 Production: Mutagenesis Induced by High Hydrostatic Pressure Treatment and Optimization of Fermentation Conditions

    Directory of Open Access Journals (Sweden)

    Yahong Yuan

    2012-01-01

    Full Text Available Coenzyme Q10 (CoQ10, ubiquinone, a potent antioxidative dietary supplement, was produced by submerged fermentation using Agrobacterium tumefaciens instead of chemical synthesis or solvent extraction. Agrobacterium tumefaciens 1.2554 was subjected to mutagenesis using a series of treatments including high hydrostatic pressure (HHP treatment, UV irradiation, and diethyl sulfate (DES treatment to obtain mutant strains showing higher CoQ10 production than wild-type strains. A mutant strain PK38 with four genetic markers was isolated: the specific CoQ10 content of the mutant strain increased by 52.83% compared with the original strain. Effects of carbon and nitrogen sources on CoQ10 production with PK38 were studied. Sucrose at concentration of 30 g/l was tested as the best carbon source, and yeast extract at concentration of 30 g/l supplemented with 10 g/l of ammonium sulfate was identified to be the most favorable for CoQ10 production using PK38. Fed-batch culture strategy was then used for increasing production of CoQ10 in 5-l fermentor. Using the exponential feeding fed-batch culture of sucrose, cell growth and CoQ10 formation were significantly improved. With this strategy, the final cell biomass, CoQ10 production, and specific CoQ10 production increased by 126.11, 173.12, and 22.76%, respectively, compared to those of batch culture.

  3. 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.

  4. 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.

  5. 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.

  6. 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

  7. High-pressure condition of SiH{sub 4}+Ar+H{sub 2} plasma for deposition of hydrogenated nanocrystalline silicon film

    Energy Technology Data Exchange (ETDEWEB)

    Parashar, A.; Kumar, Sushil; Dixit, P.N.; Gope, Jhuma; Rauthan, C.M.S. [Plasma Processed Materials Group, National Physical Laboratory, Dr. K.S. Krishnan Road, New Delhi 110012 (India); Hashmi, S.A. [Department of Physics and Astro Physics, University of Delhi, Delhi 110007 (India)

    2008-10-15

    The characteristics of 13.56-MHz discharged SiH{sub 4}+Ar+H{sub 2} plasma at high pressure (2-8 Torr), used for the deposition of hydrogenated nanocrystalline silicon (nc-Si:H) films in a capacitively coupled symmetric PECVD system, has been investigated. Plasma parameters such as average electron density, sheath field and bulk field are extracted from equivalent circuit model of the plasma using outputs (current, voltage and phase) of RF V-I probe under different pressure conditions. The conditions of growth in terms of plasma parameters are correlated with properties of the hydrogenated nanocrystalline silicon films characterized by Raman, AFM and dc conductivity. The film deposited at 4 Torr of pressure, where relatively low sheath/bulk field ratio is observed, exhibits high crystallinity and conductivity. The crystalline volume fraction of the films estimated from the Raman spectra is found to vary from 23% to 79%, and the trend of variation is similar to the RF real plasma impedance data. (author)

  8. IR-thermography-based investigation of critical heat flux in subcooled flow boiling of water at atmospheric and high pressure conditions

    Energy Technology Data Exchange (ETDEWEB)

    Bucci, Matteo [Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States); Seong, Jee H. [Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States); Buongiorno, Jdacopo [Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States); Richenderfer, Andrew [Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States); Kossolapov, A. [Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States)

    2017-11-01

    Here we report on MIT’s THM work in Q4 2016 and Q1 2017. The goal of this project is to design, construct and execute tests of flow boiling critical heat flux (CHF) at high-pressure using high-resolution and high-speed video and infrared (IR) thermometry, to generate unique data to inform the development of and validate mechanistic boiling heat transfer and CHF models. In FY2016, a new test section was designed and fabricated. Data was collected at atmospheric conditions at 10, 25 and 50 K subcoolings, and three mass fluxes, i.e. 500, 750 and 1000 kg/m2/s. Starting in Q4 2016 and continuing forward, new post-processing techniques have been developed to analyze the data collected. These new algorithms analyze the time-dependent temperature and heat flux distributions to calculate nucleation site density, nucleation frequency, growth and wait time, dry area fraction, and the complete heat flux partitioning. In Q1 2017 a new flow boiling loop was designed and constructed to support flow boiling tests up 10 bar pressure and 180 °C. Initial shakedown and testing has been completed. The flow loop and test section are now ready to begin high-pressure flow boiling testing.

  9. High-pressure crystal structure of elastically isotropic CaTiO3 perovskite under hydrostatic and non-hydrostatic conditions.

    Science.gov (United States)

    Zhao, Jing; Ross, Nancy L; Wang, Di; Angel, Ross J

    2011-11-16

    The structural evolution of orthorhombic CaTiO3 perovskite has been studied using high-pressure single-crystal x-ray diffraction under hydrostatic conditions up to 8.1 GPa and under a non-hydrostatic stress field formed in a diamond anvil cell (DAC) up to 4.7 GPa. Under hydrostatic conditions, the TiO6 octahedra become more tilted and distorted with increasing pressure, similar to other 2:4 perovskites. Under non-hydrostatic conditions, the experiments do not show any apparent difference in the internal structural variation from hydrostatic conditions and no additional tilts and distortions in the TiO6 octahedra are observed, even though the lattice itself becomes distorted due to the non-hydrostatic stress. The similarity between the hydrostatic and non-hydrostatic cases can be ascribed to the fact that CaTiO3 perovskite is nearly elastically isotropic and, as a consequence, its deviatoric unit-cell volume strain produced by the non-hydrostatic stress is very small; in other words, the additional octahedral tilts relevant to the extra unit-cell volume associated with the deviatoric unit-cell volume strain may be totally neglected. This study further addresses the role that three factors--the elastic properties, the crystal orientation and the pressure medium--have on the structural evolution of an orthorhombic perovskite loaded in a DAC under non-hydrostatic conditions. The influence of these factors can be clearly visualized by plotting the three-dimensional distribution of the deviatoric unit-cell volume strain in relation to the cylindrical axis of the DAC and indicates that, if the elasticity of a perovskite is nearly isotropic as it is for CaTiO3, the other two factors become relatively insignificant.

  10. High-pressure crystal structure of elastically isotropic CaTiO3 perovskite under hydrostatic and non-hydrostatic conditions

    International Nuclear Information System (INIS)

    Zhao Jing; Ross, Nancy L; Wang, Di; Angel, Ross J

    2011-01-01

    The structural evolution of orthorhombic CaTiO 3 perovskite has been studied using high-pressure single-crystal x-ray diffraction under hydrostatic conditions up to 8.1 GPa and under a non-hydrostatic stress field formed in a diamond anvil cell (DAC) up to 4.7 GPa. Under hydrostatic conditions, the TiO 6 octahedra become more tilted and distorted with increasing pressure, similar to other 2:4 perovskites. Under non-hydrostatic conditions, the experiments do not show any apparent difference in the internal structural variation from hydrostatic conditions and no additional tilts and distortions in the TiO 6 octahedra are observed, even though the lattice itself becomes distorted due to the non-hydrostatic stress. The similarity between the hydrostatic and non-hydrostatic cases can be ascribed to the fact that CaTiO 3 perovskite is nearly elastically isotropic and, as a consequence, its deviatoric unit-cell volume strain produced by the non-hydrostatic stress is very small; in other words, the additional octahedral tilts relevant to the extra unit-cell volume associated with the deviatoric unit-cell volume strain may be totally neglected. This study further addresses the role that three factors-the elastic properties, the crystal orientation and the pressure medium-have on the structural evolution of an orthorhombic perovskite loaded in a DAC under non-hydrostatic conditions. The influence of these factors can be clearly visualized by plotting the three-dimensional distribution of the deviatoric unit-cell volume strain in relation to the cylindrical axis of the DAC and indicates that, if the elasticity of a perovskite is nearly isotropic as it is for CaTiO 3 , the other two factors become relatively insignificant. (paper)

  11. Impact of High-Temperature, High-Pressure Synthesis Conditions on the Formation of the Grain Structure and Strength Properties of Intermetallic Ni3Al

    Science.gov (United States)

    Ovcharenko, V. E.; Ivanov, K. V.; Boyangin, E. N.; Krylova, T. A.; Pshenichnikov, A. P.

    2018-01-01

    The impact of the preliminary load on 3Ni+Al powder mixture and the impact of the duration of the delay in application of compacting pressure to synthesis product under the conditions of continuous heating of the mixture up to its self-ignition on the grain size and strength properties of the synthesized Ni3Al intermetallide material have been studied. The grain structure of the intermetallide synthesized under pressure was studied by means of metallography, transmission electron microscopy and EBSD analysis, with the dependence of ultimate tensile strength on the grain size in the synthesized intermetallide having been investigated at room temperature and at temperatures up to 1000°C. It is shown that an increase in the pressure preliminarily applied to the initial mixture compact results in reduced grain size of the final intermetallide, whereas an increase in pre-compaction time makes the grain size increased. A decrease in the grain size increases the ultimate tensile strength of the intermetallide. The maximum value of the ultimate tensile strength in the observed anomalous temperature dependence of this strength exhibits a shift by 200°C toward higher temperatures, and the ultimate strength of the synthesized intermetallide at 1000°C increases roughly two-fold.

  12. High pressure mechanical seal

    Science.gov (United States)

    Babel, Henry W. (Inventor); Anderson, Raymond H. (Inventor)

    1996-01-01

    A relatively impervious mechanical seal is formed between the outer surface of a tube and the inside surface of a mechanical fitting of a high pressure fluid or hydraulic system by applying a very thin soft metal layer onto the outer surface of the hard metal tube and/or inner surface of the hard metal fitting. The thickness of such thin metal layer is independent of the size of the tube and/or fittings. Many metals and alloys of those metals exhibit the requisite softness, including silver, gold, tin, platinum, indium, rhodium and cadmium. Suitably, the coating is about 0.0025 millimeters (0.10 mils) in thickness. After compression, the tube and fitting combination exhibits very low leak rates on the order or 10.sup.-8 cubic centimeters per second or less as measured using the Helium leak test.

  13. Common High Blood Pressure Myths

    Science.gov (United States)

    ... Disease Venous Thromboembolism Aortic Aneurysm More Common High Blood Pressure Myths Updated:May 4,2018 Knowing the facts ... This content was last reviewed October 2016. High Blood Pressure • Home • Get the Facts About HBP Introduction What ...

  14. Medications for High Blood Pressure

    Science.gov (United States)

    ... Consumers Home For Consumers Consumer Updates Medications for High Blood Pressure Share Tweet Linkedin Pin it More sharing options ... age and you cannot tell if you have high blood pressure by the way you feel, so have your ...

  15. High blood pressure and diet

    Science.gov (United States)

    ... this page: //medlineplus.gov/ency/article/007483.htm High blood pressure and diet To use the sharing features on ... diet is a proven way to help control high blood pressure . These changes can also help you lose weight ...

  16. Asymmetric Hollow Fiber Membranes for Separation of CO 2 from Hydrocarbons and Fluorocarbons at High-Pressure Conditions Relevant to C 2 F 4 Polymerization

    KAUST Repository

    Kosuri, Madhava R.

    2009-12-02

    Separation of high-pressure carbon dioxide from fluorocarbons is important for the production of fluoropolymers such as poly(tetrafluoroethylene). Typical polymeric membranes plasticize under high CO2 partial pressure conditions and fail to provide adequate selective separations. Torlon, a polyamide-imide polymer, with the ability to form interchain hydrogen bonding, is shown to provide stability against aggressive CO2 plasticization. Torlon membranes in the form of asymmetric hollow fibers (the most productive form of membranes) are considered for an intended separation of CO 2/C2F4. To avoid safety issues with tetrafluoroethylene (C2F4), which could detonate under testing conditions, safer surrogate mixtures (C2H2F 2 and C2H4) are considered in this paper. Permeation measurements (at 35 °C) indicate that the Torlon membranes are not plasticized even up to 1250 psi of CO2. The membranes provide mixed gas CO2/C2H2F2 and CO 2/C2H4 selectivities of 100 and 30, respectively, at 1250 psi partial pressures of CO2. On the basis of the measured separation performances of CO2/C2H 2F2 and CO2/C2H4 mixtures, the selectivity of the CO2/C2F4 mixture is expected to be greater than 100. Long-term stability studies indicate that the membranes provide stable separations over a period of 5 days at 1250 psi partial pressures of CO2, thereby making the membrane approach attractive. © 2009 American Chemical Society.

  17. Asymmetric Hollow Fiber Membranes for Separation of CO 2 from Hydrocarbons and Fluorocarbons at High-Pressure Conditions Relevant to C 2 F 4 Polymerization

    KAUST Repository

    Kosuri, Madhava R.; Koros, William J.

    2009-01-01

    Separation of high-pressure carbon dioxide from fluorocarbons is important for the production of fluoropolymers such as poly(tetrafluoroethylene). Typical polymeric membranes plasticize under high CO2 partial pressure conditions and fail to provide adequate selective separations. Torlon, a polyamide-imide polymer, with the ability to form interchain hydrogen bonding, is shown to provide stability against aggressive CO2 plasticization. Torlon membranes in the form of asymmetric hollow fibers (the most productive form of membranes) are considered for an intended separation of CO 2/C2F4. To avoid safety issues with tetrafluoroethylene (C2F4), which could detonate under testing conditions, safer surrogate mixtures (C2H2F 2 and C2H4) are considered in this paper. Permeation measurements (at 35 °C) indicate that the Torlon membranes are not plasticized even up to 1250 psi of CO2. The membranes provide mixed gas CO2/C2H2F2 and CO 2/C2H4 selectivities of 100 and 30, respectively, at 1250 psi partial pressures of CO2. On the basis of the measured separation performances of CO2/C2H 2F2 and CO2/C2H4 mixtures, the selectivity of the CO2/C2F4 mixture is expected to be greater than 100. Long-term stability studies indicate that the membranes provide stable separations over a period of 5 days at 1250 psi partial pressures of CO2, thereby making the membrane approach attractive. © 2009 American Chemical Society.

  18. Controlling your high blood pressure

    Science.gov (United States)

    ... medlineplus.gov/ency/patientinstructions/000101.htm Controlling your high blood pressure To use the sharing features on this page, ... JavaScript. Hypertension is another term used to describe high blood pressure. High blood pressure can lead to: Stroke Heart ...

  19. Superconductivity at high pressures

    Energy Technology Data Exchange (ETDEWEB)

    Brandt, N B; Ginzburg, N I

    1969-07-01

    Work published during the last 3 or 4 yrs concerning the effect of pressure on superconductivity is reviewed. Superconducting modifications of Si, Ge, Sb, Te, Se, P and Ce. Change of Fermi surface under pressure for nontransition metals. First experiments on the influence of pressure on the tunneling effect in superconductors provide new information on the nature of the change in phonon and electron energy spectra of metals under hydrostatic compression. 78 references.

  20. Morphology and nano-structure analysis of soot particles sampled from high pressure diesel jet flames under diesel-like conditions

    Science.gov (United States)

    Jiang, Hao; Li, Tie; Wang, Yifeng; He, Pengfei

    2018-04-01

    Soot particles emitted from diesel engines have a significant impact on the atmospheric environment. Detailed understanding of soot formation and oxidation processes is helpful for reducing the pollution of soot particles, which requires information such as the size and nano-structure parameters of the soot primary particles sampled in a high-temperature and high-pressure diesel jet flame. Based on the thermophoretic principle, a novel sampling probe minimally disturbing the diesel jet flame in a constant volume combustion vessel is developed for analysing soot particles. The injected quantity of diesel fuel is less than 10 mg, and the soot particles sampled by carriers with a transmission electron microscope (TEM) grid and lacey TEM grid can be used to analyse the morphologies of soot aggregates and the nano-structure of the soot primary particles, respectively. When the quantity of diesel fuel is more than 10 mg, in order to avoid burning-off of the carriers in higher temperature and pressure conditions, single-crystal silicon chips are employed. Ultrasonic oscillations and alcohol extraction are then implemented to obtain high quality soot samples for observation using a high-resolution transmission electron microscope. An in-house Matlab-based code is developed to extract the nano-structure parameters of the soot particles. A complete sampling and analysis procedure of the soot particles is provided to study the formation and oxidation mechanism of soot.

  1. High Blood Pressure in Pregnancy

    Science.gov (United States)

    ... of the baby. Controlling your blood pressure during pregnancy and getting regular prenatal care are important for ... your baby. Treatments for high blood pressure in pregnancy may include close monitoring of the baby, lifestyle ...

  2. Electrochemical noise measurements under pressurized water reactor conditions

    International Nuclear Information System (INIS)

    Van Nieuwenhove, R.

    2000-01-01

    Electrochemical potential noise measurements on sensitized stainless steel pressure tubes under pressurized water reactor (PWR) conditions were performed for the first time. Very short potential spikes, believed to be associated to crack initiation events, were detected when stressing the sample above the yield strength and increased in magnitude until the sample broke. Sudden increases of plastic deformation, as induced by an increased tube pressure, resulted in slower, high-amplitude potential transients, often accompanied by a reduction in noise level

  3. Effect of fat content and homogenization under conventional or ultra-high-pressure conditions on interactions between proteins in rennet curds.

    Science.gov (United States)

    Zamora, A; Trujillo, A J; Armaforte, E; Waldron, D S; Kelly, A L

    2012-09-01

    The objective of this study was to investigate the influence of conventional and ultra-high-pressure homogenization on interactions between proteins within drained rennet curds. The effect of fat content of milk (0.0, 1.8, or 3.6%) and homogenization treatment on dissociation of proteins by different chemical agents was thus studied. Increasing the fat content of raw milk increased levels of unbound whey proteins and calcium-bonded caseins in curds; in contrast, hydrophobic interactions and hydrogen bonds were inhibited. Both homogenization treatments triggered the incorporation of unbound whey proteins in the curd, and of caseins through ionic bonds involving calcium salts. Conventional homogenization-pasteurization enhanced interactions between caseins through hydrogen bonds and hydrophobic interactions. In contrast, ultra-high-pressure homogenization impaired hydrogen bonding, led to the incorporation of both whey proteins and caseins through hydrophobic interactions and increased the amount of unbound caseins. Thus, both homogenization treatments provoked changes in the protein interactions within rennet curds; however, the nature of the changes depended on the homogenization conditions. Copyright © 2012 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

  4. What Is High Blood Pressure?

    Science.gov (United States)

    ... Disease Venous Thromboembolism Aortic Aneurysm More What is High Blood Pressure? Updated:Feb 27,2018 First, let’s define high ... resources . This content was last reviewed October 2016. High Blood Pressure • Home • Get the Facts About HBP Introduction What ...

  5. 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...

  6. High pressure shaft seal

    International Nuclear Information System (INIS)

    Martinson, A.R.; Rogers, V.D.

    1980-01-01

    In relation to reactor primary coolant pumps, mechanical seal assembly for a pump shaft is disclosed which features a rotating seal ring mounting system which utilizes a rigid support ring loaded through narrow annular projections in combination with centering non-sealing O-rings which effectively isolate the rotating seal ring from temperature and pressure transients while securely positioning the ring to adjacent parts. A stationary seal ring mounting configuration allows the stationary seal ring freedom of motion to follow shaft axial movement up to 3/4 of an inch and shaft tilt about the pump axis without any change in the hydraulic or pressure loading on the stationary seal ring or its carrier. (author)

  7. Single-crystal diffraction at the Extreme Conditions beamline P02.2: procedure for collecting and analyzing high-pressure single-crystal data.

    Science.gov (United States)

    Rothkirch, André; Gatta, G Diego; Meyer, Mathias; Merkel, Sébastien; Merlini, Marco; Liermann, Hanns Peter

    2013-09-01

    Fast detectors employed at third-generation synchrotrons have reduced collection times significantly and require the optimization of commercial as well as customized software packages for data reduction and analysis. In this paper a procedure to collect, process and analyze single-crystal data sets collected at high pressure at the Extreme Conditions beamline (P02.2) at PETRA III, DESY, is presented. A new data image format called `Esperanto' is introduced that is supported by the commercial software package CrysAlis(Pro) (Agilent Technologies UK Ltd). The new format acts as a vehicle to transform the most common area-detector data formats via a translator software. Such a conversion tool has been developed and converts tiff data collected on a Perkin Elmer detector, as well as data collected on a MAR345/555, to be imported into the CrysAlis(Pro) software. In order to demonstrate the validity of the new approach, a complete structure refinement of boron-mullite (Al5BO9) collected at a pressure of 19.4 (2) GPa is presented. Details pertaining to the data collections and refinements of B-mullite are presented.

  8. High Blood Pressure - Multiple Languages

    Science.gov (United States)

    ... Being 8 - High Blood Pressure - Amarɨñña / አማርኛ (Amharic) MP3 Siloam Family Health Center Arabic (العربية) Expand Section ... Being 8 - High Blood Pressure - myanma bhasa (Burmese) MP3 Siloam Family Health Center Chinese, Simplified (Mandarin dialect) ( ...

  9. Fundamentals of high pressure adsorption

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, Y.P.; Zhou, L. [Tianjin University, Tianjin (China). High Pressure Adsorption Laboratory

    2009-12-15

    High-pressure adsorption attracts research interests following the world's attention to alternative fuels, and it exerts essential effect on the study of hydrogen/methane storage and the development of novel materials addressing to the storage. However, theoretical puzzles in high-pressure adsorption hindered the progress of application studies. Therefore, the present paper addresses the major theoretical problems that challenged researchers: i.e., how to model the isotherms with maximum observed in high-pressure adsorption; what is the adsorption mechanism at high pressures; how do we determine the quantity of absolute adsorption based on experimental data. Ideology and methods to tackle these problems are elucidated, which lead to new insights into the nature of high-pressure adsorption and progress in application studies, for example, in modeling multicomponent adsorption, hydrogen storage, natural gas storage, and coalbed methane enrichment, was achieved.

  10. Effects of pre- or post-processing storage conditions on high-hydrostatic pressure inactivation of Vibrio parahaemolyticus and V. vulnificus in oysters.

    Science.gov (United States)

    Ye, Mu; Huang, Yaoxin; Gurtler, Joshua B; Niemira, Brendan A; Sites, Joseph E; Chen, Haiqiang

    2013-05-15

    The effects of storage conditions on subsequent high-hydrostatic pressure (HHP) inactivation of Vibrio parahaemolyticus and Vibrio vulnificus in oysters were investigated. Live oysters were inoculated with V. parahaemolyticus or V. vulnificus to ca. 7-8 log MPN/g by feeding and stored at varying conditions (i.e., 21 or 35 °C for 5h, 4 or 10 °C for 1 and 2 days and -18 °C for 2 weeks). Oyster meats were then treated at 225-300 MPa for 2 min at 4, 21 or 35 °C. HHP at 300 MPa for 2 min achieved a >5-log MPN/g reduction of V. parahaemolyticus, completely inactivating V. vulnificus (negative by enrichment) in oysters. Treatment temperatures of 4, 21 and 35 °C did not significantly affect pressure inactivation of V. parahaemolyticus or V. vulnificus (P>0.05). Cold storage at -18, 4 and 10 °C, prior to HHP, decreased V. parahaemolyticus or V. vulnificus populations by 1.5-3.0 log MPN/g, but did not increase their sensitivity to subsequent HHP treatments. The effects of cold storage after HHP on inactivation of V. parahaemolyticus in oysters were also determined. Oysters were inoculated with V. parahaemolyticus and stored at 21 °C for 5h or 4 °C for 1 day. Oyster meats were then treated at 250-300 MPa for 2 min at 21 or 35 °C and stored for 15 days in ice or in a freezer. V. parahaemolyticus populations in HHP-treated oysters gradually decreased during post-HHP ice or frozen storage. A validation study using whole-shell oysters was conducted to determine whether the presence of oyster shells influenced HHP inactivation of V. parahaemolyticus. No appreciable differences in inactivation between shucked oyster meat and whole-shell oysters were observed. HPP at 300 MPa for 2 min at 21 °C, followed by 5-day ice storage or 7-day frozen storage, and HPP at 250 MPa for 2 min at 21 °C, followed by 10-day ice or 7-day frozen storage, completely inactivated V. parahaemolyticus in whole-shell oysters (>7 log reductions). The combination of HHP at a relatively low pressure

  11. High pressure X-ray studies

    International Nuclear Information System (INIS)

    Sikka, S.K.

    1981-01-01

    High pressure research has already led to new insights in the physical properties of materials and at times to the synthesis of new ones. In all this, X-ray diffraction has been a valuable diagnostic experimental tool. In particular, X-rays in high pressure field have been used (a) for crystallographic identification of high pressure polymorphs and (b) for study of the effect of pressure on lattice parameters and volume under isothermal conditions. The results in the area (a) are reviewed. The techniques of applying high pressures are described. These include both static and dynamic shockwave X-ray apparatus. To illustrate the effect of pressure, some of the pressure induced phase transitions in pure metals are described. It has been found that there is a clear trend for elements in any group of the periodic table to adopt similar structures at high pressures. These studies have enabled to construct generalized phase diagrams for many groups. In the case of alloys, the high pressure work done on Ti-V alloys is presented. (author)

  12. Microstructure and mechanical properties of AM50 alloy according to thickness and forming condition of the products by a high pressure die-casting process

    Energy Technology Data Exchange (ETDEWEB)

    Park, Joon Hong [Dong-A University, Busan (Korea, Republic of); Kang, Chung Gil [Pusan National University, Busan (Korea, Republic of)

    2013-10-15

    In recent years, Magnesium (Mg) and its alloys have become a center of special interest in the automotive industry. Due to their high specific mechanical properties, they offer a significant weight saving potential in modern vehicle constructions. Most Mg alloys show very good machinability and processability, and even the most complicated die casting parts can be easily produced. The die casting process is a fast production method capable of a high degree of automation for which certain Mg alloys are ideally suited. Although Mg alloys are fulfilling the demands for low specific weight materials with excellent machining and casting abilities, they are still not used in die casting process to the same extent as the competing material aluminum. One of the reasons is that effects of various forming variables for die casting process is not closely examined from the viewpoint of die design. In this study, step die and flowability tests for AM50 were performed by die casting process according to various combination of casting pressure and plunger velocity. Microstructure, Vickers hardness and tensile tests were examined and performed for each specimen to verify effects of forming conditions.

  13. 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

  14. Psoriasis and high blood pressure.

    Science.gov (United States)

    Salihbegovic, Eldina Malkic; Hadzigrahic, Nermina; Suljagic, Edin; Kurtalic, Nermina; Sadic, Sena; Zejcirovic, Alema; Mujacic, Almina

    2015-02-01

    Psoriasis is a chronic skin ailment which can be connected with an increased occurrence of other illnesses, including high blood pressure. A prospective study has been conducted which included 70 patients affected by psoriasis, both genders, older than 18 years. Average age being 47,14 (SD= ±15,41) years, from that there were 36 men or 51,43 and 34 women or 48,57%. Average duration of psoriasis was 15,52 (SD=±12,54) years. Frequency of high blood pressure in those affected by psoriasis was 54,28%. Average age of the patients with psoriasis and high blood pressure was 53,79 year (SD=±14,15) and average duration of psoriasis was 17,19 years (SD=±13,51). Average values of PASI score were 16,65. Increase in values of PASI score and high blood pressure were statistically highly related (r=0,36, p=0,0001). Psoriasis was related to high blood pressure and there was a correlation between the severity of psoriasis and high blood pressure.

  15. High Blood Pressure and Women

    Science.gov (United States)

    ... is known as gestational hypertension, a form of secondary hypertension caused by the pregnancy that usually disappears after delivery. If the mother is not treated, high blood pressure can be dangerous to both the mother ...

  16. High Pressure Industrial Water Facility

    Science.gov (United States)

    1992-01-01

    In conjunction with Space Shuttle Main Engine testing at Stennis, the Nordberg Water Pumps at the High Pressure Industrial Water Facility provide water for cooling the flame deflectors at the test stands during test firings.

  17. High Pressure Research on Materials

    Indian Academy of Sciences (India)

    example, represents the stress on the x plane in the y direction. There are three .... optical studies and studying compressibility of fluids. 3.2 Opposed ..... [4] G N Peggs, High Pressure Measurement Techniques, Applied Science. Publishers ...

  18. Application of High Pressure in Food Processing

    Directory of Open Access Journals (Sweden)

    Herceg, Z.

    2011-01-01

    Full Text Available In high pressure processing, foods are subjected to pressures generally in the range of 100 – 800 (1200 MPa. The processing temperature during pressure treatments can be adjusted from below 0 °C to above 100 °C, with exposure times ranging from a few seconds to 20 minutes and even longer, depending on process conditions. The effects of high pressure are system volume reduction and acceleration of reactions that lead to volume reduction. The main areas of interest regarding high-pressure processing of food include: inactivation of microorganisms, modification of biopolymers, quality retention (especially in terms of flavour and colour, and changes in product functionality. Food components responsible for the nutritive value and sensory properties of food remain unaffected by high pressure. Based on the theoretical background of high-pressure processing and taking into account its advantages and limitations, this paper aims to show its possible application in food processing. The paper gives an outline of the special equipment used in highpressure processing. Typical high pressure equipment in which pressure can be generated either by direct or indirect compression are presented together with three major types of high pressure food processing: the conventional (batch system, semicontinuous and continuous systems. In addition to looking at this technology’s ability to inactivate microorganisms at room temperature, which makes it the ultimate alternative to thermal treatments, this paper also explores its application in dairy, meat, fruit and vegetable processing. Here presented are the effects of high-pressure treatment in milk and dairy processing on the inactivation of microorganisms and the modification of milk protein, which has a major impact on rennet coagulation and curd formation properties of treated milk. The possible application of this treatment in controlling cheese manufacture, ripening and safety is discussed. The opportunities

  19. Prokaryotic degradation of high molecular weight dissolved organic matter in the deep-sea waters of NW Mediterranean Sea under in situ temperature and pressure conditions during contrasted hydrological conditions

    Science.gov (United States)

    Tamburini, C.; Boutrif, M.; Garel, M.; Sempéré, R.; Repeta, D.; Charriere, B.; Nerini, D.; Panagiotopoulos, C.

    2016-02-01

    The contribution of the semi-labile dissolved organic carbon (DOC) to the global prokaryotic production has been assessed in very few previous studies. Some experiments show rapid utilization of semi-reactive DOC by prokaryotes, while other experiments show almost no utilization at all. However, all these studies did not take into account the role of hydrostatic pressure for the degradation of organic matter. In this study, we investigate (1) the degradation of "natural" high molecular weight DOM HMW-DOM (obtained after ultrafiltration) and (2) the uptake of labeled extracellular polymeric substances (3H-EPS) incubated with deep-sea water samples (2000 m-depth, NW Mediterranean Sea) under in situ pressure conditions (HP) and under atmospheric compression after decompression of the deep samples (ATM) during stratified and mixed water conditions (deep sea convection). Our results indicated that during HP incubations DOC exhibited the highest degradation rates (kHP DOC = 0.82 d-1) compared to the ATM conditions were no or few degradation was observed (kATM DOC= 0.007 d-1). An opposite trend was observed for the HP incubations from mixed deep water masses. HP incubation measurements displayed the lowest DOC degradation (kHP DOC=0.031 d-1) compared to the ATM conditions (kATM DOC=0.62 d-1). These results imply the presence of allochthonous prokaryotic cells in deep-sea samples after a winter water mass convection. Same trends were found using 3H-EPS uptake rates which were higher at HP than at ATM conditions during stratified period conditions whereas the opposite patterns were observed during deep-sea convection event. Moreover, we found than Euryarchaea were the main contributors to 3H-EPS assimilation at 2000m-depth, representing 58% of the total cells actively assimilating 3H-EPS. This study demonstrates that remineralization rates of semi-labile DOC in deep NW Med. Sea are controlled by the prokaryotic communities, which are influenced by the hydrological

  20. High Blood Pressure (Hypertension) (For Parents)

    Science.gov (United States)

    ... Safe Videos for Educators Search English Español Hypertension (High Blood Pressure) KidsHealth / For Parents / Hypertension (High Blood Pressure) What's ... High Blood Pressure) Treated? Print What Is Hypertension (High Blood Pressure)? Blood pressure is the pressure of blood against ...

  1. High Blood Pressure, Afib and Your Risk of Stroke

    Science.gov (United States)

    ... Peripheral Artery Disease Venous Thromboembolism Aortic Aneurysm More High Blood Pressure, AFib and Your Risk of Stroke Updated:Aug ... have a stroke for the first time have high blood pressure . And an irregular atrial heart rhythm — a condition ...

  2. A computational study of syngas auto-ignition characteristics at high-pressure and low-temperature conditions with thermal inhomogeneities

    KAUST Repository

    Pal, Pinaki

    2015-07-30

    A computational study was conducted to investigate the characteristics of auto-ignition in a syngas mixture at high-pressure and low-temperature conditions in the presence of thermal inhomogeneities. Highly resolved one-dimensional numerical simulations incorporating detailed chemistry and transport were performed. The temperature inhomogeneities were represented by a global sinusoidal temperature profile and a local Gaussian temperature spike (hot spot). Reaction front speed and front Damköhler number analyses were employed to characterise the propagating ignition front. In the presence of a global temperature gradient, the ignition behaviour shifted from spontaneous propagation (strong) to deflagrative (weak), as the initial mean temperature of the reactant mixture was lowered. A predictive Zel\\'dovich–Sankaran criterion to determine the transition from strong to weak ignition was validated for different parametric sets. At sufficiently low temperatures, the strong ignition regime was recovered due to faster passive scalar dissipation of the imposed thermal fluctuations relative to the reaction timescale, which was quantified by the mixing Damköhler number. In the presence of local hot spots, only deflagrative fronts were observed. However, the fraction of the reactant mixture consumed by the propagating front was found to increase as the initial mean temperature was lowered, thereby leading to more enhanced compression-heating of the end-gas. Passive scalar mixing was not found to be important for the hot spot cases considered. The parametric study confirmed that the relative magnitude of the Sankaran number translates accurately to the quantitative strength of the deflagration front in the overall ignition advancement. © 2015 Taylor & Francis

  3. A computational study of syngas auto-ignition characteristics at high-pressure and low-temperature conditions with thermal inhomogeneities

    Science.gov (United States)

    Pal, Pinaki; Mansfield, Andrew B.; Arias, Paul G.; Wooldridge, Margaret S.; Im, Hong G.

    2015-09-01

    A computational study was conducted to investigate the characteristics of auto-ignition in a syngas mixture at high-pressure and low-temperature conditions in the presence of thermal inhomogeneities. Highly resolved one-dimensional numerical simulations incorporating detailed chemistry and transport were performed. The temperature inhomogeneities were represented by a global sinusoidal temperature profile and a local Gaussian temperature spike (hot spot). Reaction front speed and front Damköhler number analyses were employed to characterise the propagating ignition front. In the presence of a global temperature gradient, the ignition behaviour shifted from spontaneous propagation (strong) to deflagrative (weak), as the initial mean temperature of the reactant mixture was lowered. A predictive Zel'dovich-Sankaran criterion to determine the transition from strong to weak ignition was validated for different parametric sets. At sufficiently low temperatures, the strong ignition regime was recovered due to faster passive scalar dissipation of the imposed thermal fluctuations relative to the reaction timescale, which was quantified by the mixing Damköhler number. In the presence of local hot spots, only deflagrative fronts were observed. However, the fraction of the reactant mixture consumed by the propagating front was found to increase as the initial mean temperature was lowered, thereby leading to more enhanced compression-heating of the end-gas. Passive scalar mixing was not found to be important for the hot spot cases considered. The parametric study confirmed that the relative magnitude of the Sankaran number translates accurately to the quantitative strength of the deflagration front in the overall ignition advancement.

  4. Terbium oxide at high pressures

    International Nuclear Information System (INIS)

    Dogra, Sugandha; Sharma, Nita Dilawar; Singh, Jasveer; Bandhyopadhyay, A.K.

    2011-01-01

    In this work we report the behaviour of terbium oxide at high pressures. The as received sample was characterized at ambient by X-ray diffraction and Raman spectroscopy. The X-ray diffraction showed the sample to be predominantly cubic Tb 4 O 7 , although a few peaks also match closely with Tb 2 O 3 . In fact in a recent study done on the same sample, the sample has been shown to be a mixture of Tb 4 O 7 and Tb 2 O 3 . The sample was subjected to high pressures using a Mao-Bell type diamond anvil cell upto a pressure of about 42 GPa with ruby as pressure monitor

  5. High Pressure Treatment in Foods

    OpenAIRE

    Edwin Fabian Torres Bello; Gerardo González Martínez; Bernadette F. Klotz Ceberio; Dolores Rodrigo; Antonio Martínez López

    2014-01-01

    Abstract: High hydrostatic pressure (HHP), a non-thermal technology, which typically uses water as a pressure transfer medium, is characterized by a minimal impact on food characteristics (sensory, nutritional, and functional). Today, this technology, present in many food companies, can effectively inactivate bacterial cells and many enzymes. All this makes HHP very attractive, with very good acceptance by consumers, who value the organoleptic characteristics of products processed by this non...

  6. Bulging of pressure tubes at hot spots under LOCA conditions

    International Nuclear Information System (INIS)

    Manu, C.; Shewfelt, R.S.W.; Wright, A.C.D.; Aboud, R.; Lau, J.H.K.; Sanderson, D.B.

    1996-01-01

    During certain postulated loss-of-coolant accidents (LOCA) in a CANDU reactor, some fuel channels can become highly voided within a very short time. Although the pressure tubes are heated mainly by convection and thermal radiation during the LOCA transient, additional heat flow occurs through the bearing pads that are in contact with the pressure tribe. This contact can lead to local hot spots and associated thermal stresses in the pressure tube wall. The two factors that affects the behavior of the pressure tubes during LOCA conditions are the internal pressure and the local heating. Although the effect of internal pressure and of axially uniform temperature has been studied elsewhere, the effect of the local heating on the pressure tube behavior has not been modelled before. This paper shows that the bulging of a pressure tube at a hot spot is the result of the thermal stresses that are developed in a pressure tube during a LOCA transient. To isolate the local heating effect from the internal pressure, a series of single-effect experiments was performed. In these experiments, sections of a CANDU pressure tube were subjected to local heating only. The thermal profile and the local deformation were measured function of time. To quantify the effect of the thermal stresses on the bulging of pressure tubes at hot spots and to develop numerical tools that can predict such bulging, finite element analyses were performed rising the ABAQUS finite element computer code. Use of the measured thermal profiles in the ABAQUS finite element analysis, resulted in very good agreement between the predicted and measured displacements. (author)

  7. Experimental investigations of two-phase mixture level swell and axial void fraction distribution under high pressure, low heat flux conditions in rod bundle geometry

    International Nuclear Information System (INIS)

    Anklam, T.M.; White, M.D.

    1981-01-01

    Experimental data is reported from a series of quasi-steady-state two-phase mixture level swell and void fraction distribution tests. Testing was performed at ORNL in the Thermal Hydraulic Test Facility - a large electrically heated test loop configured to produce conditions similar to those expected in a small break loss of coolant accident. Pressure was varied from 2.7 to 8.2 MPa and linear power ranged from 0.33 to 1.95 kW/m. Mixture swell was observed to vary linearly with the total volumetric vapor generation rate over the power range of primary interest in small break analysis. Void fraction data was fit by a drift-flux model and both the drift-velocity and concentration parameter were observed to decrease with increasing pressure

  8. Pressure vessel failure at high internal pressure

    International Nuclear Information System (INIS)

    Laemmer, H.; Ritter, B.

    1995-01-01

    A RPV failure due to plastic instability was investigated using the ABAQUS finite element code together with a material model of thermal plasticity for large deformations. Not only rotational symmetric temperature distributions were studied, but also 'hot spots'. Calculations show that merely by the depletion of strength of the material - even at internal wall temperatures well below the melting point of the fuel elements of about 2000/2400 C - the critical internal pressure can decrease to values smaller than the operational pressure of 16 Mpa. (orig.)

  9. Computer simulation at high pressure

    International Nuclear Information System (INIS)

    Alder, B.J.

    1977-11-01

    The use of either the Monte Carlo or molecular dynamics method to generate equations-of-state data for various materials at high pressure is discussed. Particular emphasis is given to phase diagrams, such as the generation of various types of critical lines for mixtures, melting, structural and electronic transitions in solids, two-phase ionic fluid systems of astrophysical interest, as well as a brief aside of possible eutectic behavior in the interior of the earth. Then the application of the molecular dynamics method to predict transport coefficients and the neutron scattering function is discussed with a view as to what special features high pressure brings out. Lastly, an analysis by these computational methods of the measured intensity and frequency spectrum of depolarized light and also of the deviation of the dielectric measurements from the constancy of the Clausius--Mosotti function is given that leads to predictions of how the electronic structure of an atom distorts with pressure

  10. Anxiety: A Cause of High Blood Pressure?

    Science.gov (United States)

    ... of high blood pressure? Can anxiety cause high blood pressure? Answers from Sheldon G. Sheps, M.D. Anxiety doesn't cause long-term high blood pressure (hypertension). But episodes of anxiety can cause dramatic, ...

  11. African Americans and High Blood Pressure

    Science.gov (United States)

    ANSWERS by heart Lifestyle + Risk Reduction High Blood Pressure What About African Americans and High Blood Pressure? African Americans in the U.S. have a higher prevalence of high blood pressure (HBP) than ...

  12. High Blood Pressure: Medicines to Help You

    Science.gov (United States)

    ... For Consumers Consumer Information by Audience For Women High Blood Pressure--Medicines to Help You Share Tweet Linkedin Pin ... Click here for the Color Version (PDF 533KB) High blood pressure is a serious illness. High blood pressure is ...

  13. High-pressure sodium lamp

    NARCIS (Netherlands)

    1996-01-01

    A high pressure sodium lamp of the invention is provided with a discharge vessel (20) which is enclosed with intervening space (1) by an outer bulb (10), which space contains a gas-fill with at least 70 mol. % nitrogen gas. Electrodes (30a, 30b) are positioned in the discharge vessel (20) and are

  14. Intermolecular Interactions at high pressure

    DEFF Research Database (Denmark)

    Eikeland, Espen Zink

    2016-01-01

    In this project high-pressure single crystal X-ray diffraction has been combined with quantitative energy calculations to probe the energy landscape of three hydroquinone clathrates enclosing different guest molecules. The simplicity of the hydroquinone clathrate structures together with their st...

  15. High-pressure water facility

    Science.gov (United States)

    2006-01-01

    NASA Test Operations Group employees, from left, Todd Pearson, Tim Delcuze and Rodney Wilkinson maintain a water pump in Stennis Space Center's high-pressure water facility. The three were part of a group of employees who rode out Hurricane Katrina at the facility and helped protect NASA's rocket engine test complex.

  16. Vital Signs - High Blood Pressure

    Centers for Disease Control (CDC) Podcasts

    2012-10-02

    In the U.S., nearly one third of the adult population have high blood pressure, the leading risk factor for heart disease and stroke - two of the nation's leading causes of death.  Created: 10/2/2012 by National Center for Chronic Disease Prevention and Health Promotion (NCCDPHP).   Date Released: 10/17/2012.

  17. High Pressure Treatment in Foods

    Science.gov (United States)

    Torres Bello, Edwin Fabian; González Martínez, Gerardo; Klotz Ceberio, Bernadette F.; Rodrigo, Dolores; Martínez López, Antonio

    2014-01-01

    High hydrostatic pressure (HHP), a non-thermal technology, which typically uses water as a pressure transfer medium, is characterized by a minimal impact on food characteristics (sensory, nutritional, and functional). Today, this technology, present in many food companies, can effectively inactivate bacterial cells and many enzymes. All this makes HHP very attractive, with very good acceptance by consumers, who value the organoleptic characteristics of products processed by this non-thermal food preservation technology because they associate these products with fresh-like. On the other hand, this technology reduces the need for non-natural synthetic additives of low consumer acceptance. PMID:28234332

  18. High Pressure Treatment in Foods

    Directory of Open Access Journals (Sweden)

    Edwin Fabian Torres Bello

    2014-08-01

    Full Text Available High hydrostatic pressure (HHP, a non-thermal technology, which typically uses water as a pressure transfer medium, is characterized by a minimal impact on food characteristics (sensory, nutritional, and functional. Today, this technology, present in many food companies, can effectively inactivate bacterial cells and many enzymes. All this makes HHP very attractive, with very good acceptance by consumers, who value the organoleptic characteristics of products processed by this non-thermal food preservation technology because they associate these products with fresh-like. On the other hand, this technology reduces the need for non-natural synthetic additives of low consumer acceptance.

  19. 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...

  20. High Blood Pressure: Unique to Older Adults

    Science.gov (United States)

    ... our e-newsletter! Aging & Health A to Z High Blood Pressure Hypertension Unique to Older Adults This section provides ... Pressure Targets are Different for Very Old Adults High blood pressure (also called hypertension) increases your chance of having ...

  1. Hydrogen - High pressure production and storage

    International Nuclear Information System (INIS)

    Lauretta, J.R

    2005-01-01

    The development of simple, safe and more and more efficient technologies for the production and the storage of hydrogen is necessary condition for the transition towards the economy of hydrogen.In this work the hydrogen production studies experimentally to high pressure by electrolysis of alkaline solutions without the intervention of compressing systems and its direct storage in safe containers.The made tests show that the process of electrolysis to high pressure is feasible and has better yield than to low pressure, and that is possible to solve the operation problems, with relatively simple technology.The preliminary studies and tests indicate that the system container that studied is immune to the outbreak and can have forms and very different sizes, nevertheless, to reach or to surpass the efficiency of storage of the conventional systems the investments necessary will be due to make to be able to produce aluminum alloy tubes of high resistance

  2. Radionuclides release from re-irradiated fuel under high temperature and pressure conditions. Gamma-ray measurements of VEGA-5 test

    Energy Technology Data Exchange (ETDEWEB)

    Hidaka, Akihide; Kudo, Tamotsu; Nakamura, Takehiko; Kanazawa, Toru; Kiuchi, Toshio; Uetsuka, Hiroshi [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

    2003-03-01

    The VEGA (Verification Experiments of radionuclides Gas/Aerosol release) program is being performed at JAERI to clarify mechanisms of radionuclides release from irradiated fuel during severe accidents and to improve source term predictability. The fifth VEGA-5 test was conducted in January 2002 to confirm the reproducibility of decrease in cesium release under elevated pressure that was observed in the VEGA-2 test and to investigate the release behavior of short-life radionuclides. The PWR fuel of 47 GWd/tU after about 8.2 years of cooling was re-irradiated at Nuclear Safety Research Reactor (NSRR) for 8 hours before the heat-up test. After that, the two pellets of 10.9 g without cladding were heated up to about 2,900 K at 1.0 MPa under the inert He condition. The experiment reconfirmed the decrease in cesium release rate under the elevated pressure. The release data on short-life radionuclides such as Ru-103, Ba-140 and Xe-133 that have never been observed in the previous VEGA tests without re-irradiation was obtained using the {gamma} ray measurement. (author)

  3. High pressure effects on fruits and vegetables

    OpenAIRE

    Timmermans, R.A.H.; Matser, A.M.

    2016-01-01

    The chapter provides an overview on different high pressure based treatments (high pressure pasteurization, blanching, pressure-assisted thermal processing, pressure-shift freezing and thawing) available for the preservation of fruits and vegetable products and extending their shelf life. Pressure treatment can be used for product modification through pressure gelatinization of starch and pressure denaturation of proteins. Key pressure–thermal treatment effects on vitamin, enzymes, flavor, co...

  4. Brillouin scattering at high pressures

    International Nuclear Information System (INIS)

    Grimsditch, M.; Polian, A.

    1988-02-01

    Technical advances which have made Brillouin scattering a useful tool in high pressure diamond anvil cell (DAC) studies, viz. multipassing and tandem operation of Fabry-Perot interferometers, are reviewed. Experimental aspects, such as allowed scattering geometries, are outlined and the data analysis required to transform Brillouin spectra into sound velocities and elastic constants is presented. Experimental results on H 2 , N 2 , Ar, and He are presented, and the close relationship between the Brillouin scattering results and equations of state is highlighted

  5. High pressure effects on fruits and vegetables

    NARCIS (Netherlands)

    Timmermans, R.A.H.; Matser, A.M.

    2016-01-01

    The chapter provides an overview on different high pressure based treatments (high pressure pasteurization, blanching, pressure-assisted thermal processing, pressure-shift freezing and thawing) available for the preservation of fruits and vegetable products and extending their shelf life. Pressure

  6. 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.

  7. Cobalt ferrite nanoparticles under high pressure

    Energy Technology Data Exchange (ETDEWEB)

    Saccone, F. D.; Ferrari, S.; Grinblat, F.; Bilovol, V. [Instituto de Tecnologías y Ciencias de la Ingeniería, “Ing. H. Fernández Long,” Av. Paseo Colón 850 (1063), Buenos Aires (Argentina); Errandonea, D., E-mail: daniel.errandonea@uv.es [Departamento de Fisica Aplicada, Institut Universitari de Ciència dels Materials, Universitat de Valencia, c/ Doctor Moliner 50, E-46100 Burjassot, Valencia (Spain); Agouram, S. [Departamento de Física Aplicada y Electromagnetismo, Universitat de València, 46100 Burjassot, Valencia (Spain)

    2015-08-21

    We report by the first time a high pressure X-ray diffraction and Raman spectroscopy study of cobalt ferrite (CoFe{sub 2}O{sub 4}) nanoparticles carried out at room temperature up to 17 GPa. In contrast with previous studies of nanoparticles, which proposed the transition pressure to be reduced from 20–27 GPa to 7.5–12.5 GPa (depending on particle size), we found that cobalt ferrite nanoparticles remain in the spinel structure up to the highest pressure covered by our experiments. In addition, we report the pressure dependence of the unit-cell parameter and Raman modes of the studied sample. We found that under quasi-hydrostatic conditions, the bulk modulus of the nanoparticles (B{sub 0} = 204 GPa) is considerably larger than the value previously reported for bulk CoFe{sub 2}O{sub 4} (B{sub 0} = 172 GPa). In addition, when the pressure medium becomes non-hydrostatic and deviatoric stresses affect the experiments, there is a noticeable decrease of the compressibility of the studied sample (B{sub 0} = 284 GPa). After decompression, the cobalt ferrite lattice parameter does not revert to its initial value, evidencing a unit cell contraction after pressure was removed. Finally, Raman spectroscopy provides information on the pressure dependence of all Raman-active modes and evidences that cation inversion is enhanced by pressure under non-hydrostatic conditions, being this effect not fully reversible.

  8. HIGH PRESSURE COAL COMBUSTON KINETICS PROJECT

    Energy Technology Data Exchange (ETDEWEB)

    Stefano Orsino

    2005-03-30

    As part of the U.S. Department of Energy (DoE) initiative to improve the efficiency of coal-fired power plants and reduce the pollution generated by these facilities, DOE has funded the High-Pressure Coal Combustion Kinetics (HPCCK) Projects. A series of laboratory experiments were conducted on selected pulverized coals at elevated pressures with the specific goals to provide new data for pressurized coal combustion that will help extend to high pressure and validate models for burnout, pollutant formation, and generate samples of solid combustion products for analyses to fill crucial gaps in knowledge of char morphology and fly ash formation. Two series of high-pressure coal combustion experiments were performed using SRI's pressurized radiant coal flow reactor. The first series of tests characterized the near burner flame zone (NBFZ). Three coals were tested, two high volatile bituminous (Pittsburgh No.8 and Illinois No.6), and one sub-bituminous (Powder River Basin), at pressures of 1, 2, and 3 MPa (10, 20, and 30 atm). The second series of experiments, which covered high-pressure burnout (HPBO) conditions, utilized a range of substantially longer combustion residence times to produce char burnout levels from 50% to 100%. The same three coals were tested at 1, 2, and 3 MPa, as well as at 0.2 MPa. Tests were also conducted on Pittsburgh No.8 coal in CO2 entrainment gas at 0.2, 1, and 2 MPa to begin establishing a database of experiments relevant to carbon sequestration techniques. The HPBO test series included use of an impactor-type particle sampler to measure the particle size distribution of fly ash produced under complete burnout conditions. The collected data have been interpreted with the help of CFD and detailed kinetics simulation to extend and validate devolatilization, char combustion and pollutant model at elevated pressure. A global NOX production sub-model has been proposed. The submodel reproduces the performance of the detailed chemical

  9. High Pressure Electrolyzer System Evaluation

    Science.gov (United States)

    Prokopius, Kevin; Coloza, Anthony

    2010-01-01

    This report documents the continuing efforts to evaluate the operational state of a high pressure PEM based electrolyzer located at the NASA Glenn Research Center. This electrolyzer is a prototype system built by General Electric and refurbished by Hamilton Standard (now named Hamilton Sunstrand). It is capable of producing hydrogen and oxygen at an output pressure of 3000 psi. The electrolyzer has been in storage for a number of years. Evaluation and testing was performed to determine the state of the electrolyzer and provide an estimate of the cost for refurbishment. Pressure testing was performed using nitrogen gas through the oxygen ports to ascertain the status of the internal membranes and seals. It was determined that the integrity of the electrolyzer stack was good as there were no appreciable leaks in the membranes or seals within the stack. In addition to the integrity testing, an itemized list and part cost estimate was produced for the components of the electrolyzer system. An evaluation of the system s present state and an estimate of the cost to bring it back to operational status was also produced.

  10. Heat transfer study under supercritical pressure conditions

    International Nuclear Information System (INIS)

    Yamashita, Tohru; Yoshida, Suguru; Mori, Hideo; Morooka, Shinichi; Komita, Hideo; Nishida, Kouji

    2003-01-01

    Experiments were performed on heat transfer and pressure drop of a supercritical pressure fluid flowing upward in a uniformly heated vertical tube of a small diameter, using HCFC22 as a test fluid. Following results were obtained. (1) Characteristics of the heat transfer are similar to those for the tubes of large diameter. (2) The effect of tube diameter on the heat transfer was seen for a 'normal heat transfer, but not for a 'deteriorated' heat transfer. (3) The limit heat flux for the occurrence of deterioration in heat transfer becomes larger with smaller diameter tube. (4) The Watts and Chou correlation has the best prediction performance for the present data in the 'normal' heat transfer region. (5) Frictional pressure drop becomes smaller than that for an isothermal flow in the region near the pseudocritical point, and this reduction was more remarkable for the deteriorated' heat transfer. (author)

  11. Raman study of opal at high pressure

    Science.gov (United States)

    Farfan, G.; Wang, S.; Mao, W. L.

    2011-12-01

    More commonly known for their beauty and lore as gemstones, opals are also intriguing geological materials which may have potential for materials science applications. Opal lacks a definite crystalline structure, and is composed of an amorphous packing of hydrated silica (SiO2) spheroids, which provides us with a unique nano-scaled mineraloid with properties unlike those of other amorphous materials like glass. Opals from different localities were studied at high pressure using a diamond anvil cell to apply pressure and Raman spectroscopy to look at changes in bonding as pressure was increased. We first tested different samples from Virgin Valley, NV, Spencer, ID, Juniper Ridge, OR, and Australia, which contain varying amounts of water at ambient conditions, using Raman spectroscopy to determine if they were opal-CT (semicrystalline cristobalite-trydimite volcanic origin) or opal-A (amorphous sedimentary origin). We then used x-ray diffraction and Raman spectroscopy in a diamond anvil cell to see how their bonding and structure changed under compression and to determine what effect water content had on their high pressure behavior. Comparison of our results on opal to other high pressure studies of amorphous materials like glass has implications from a geological and materials science standpoint.

  12. Determining the microwave coupling and operational efficiencies of a microwave plasma assisted chemical vapor deposition reactor under high pressure diamond synthesis operating conditions

    Energy Technology Data Exchange (ETDEWEB)

    Nad, Shreya [Department of Electrical and Computer Engineering, Michigan State University, East Lansing, Michigan 48824 (United States); Department of Physics and Astronomy, Michigan State University, East Lansing, Michigan 48824 (United States); Gu, Yajun; Asmussen, Jes [Department of Electrical and Computer Engineering, Michigan State University, East Lansing, Michigan 48824 (United States)

    2015-07-15

    The microwave coupling efficiency of the 2.45 GHz, microwave plasma assisted diamond synthesis process is investigated by experimentally measuring the performance of a specific single mode excited, internally tuned microwave plasma reactor. Plasma reactor coupling efficiencies (η) > 90% are achieved over the entire 100–260 Torr pressure range and 1.5–2.4 kW input power diamond synthesis regime. When operating at a specific experimental operating condition, small additional internal tuning adjustments can be made to achieve η > 98%. When the plasma reactor has low empty cavity losses, i.e., the empty cavity quality factor is >1500, then overall microwave discharge coupling efficiencies (η{sub coup}) of >94% can be achieved. A large, safe, and efficient experimental operating regime is identified. Both substrate hot spots and the formation of microwave plasmoids are eliminated when operating within this regime. This investigation suggests that both the reactor design and the reactor process operation must be considered when attempting to lower diamond synthesis electrical energy costs while still enabling a very versatile and flexible operation performance.

  13. High pressure research at CHESS

    International Nuclear Information System (INIS)

    Brister, K.

    1992-01-01

    Since February 1990 there has been a dedicated high pressure line at the Cornell High Energy Synchrotron Source (CHESS). This facility provides X-ray instrumentation for energy dispersive X-ray diffraction and Laue diffraction using diamond anvil cells. Both hard-bend magnet and wiggler radiation are available as well as focused monochromatic radiation. In addition, support instrumentation is also available; a ruby system, laser heating, sample loading, and data analysis software. Experienced users need only to bring their diamond anvil cells and samples and can leave with the initial data analysis finished. Research using diamond anvil cells will be introduced and the facility will be described. Some of the diamond anvil cell research done at CHESS will be reviewed, including crystalline to amorphous transitions (R.R. Winters et al., Chem. Phys, in press), properties of C 6 0 under stress (S.J. Duclos et al., Nature 351 (1991) 380), deep earthquakes (T.C. Wu et al., submitted to J. Geophys. Res.)l, and reaching pressures of the center of Earth (A.L. Ruoff et al., Rev. Sci. Instr. 61 (1990) 3830). (orig.)

  14. Strain engineered pyrochlore at high pressure

    Energy Technology Data Exchange (ETDEWEB)

    Rittman, Dylan R.; Turner, Katlyn M.; Park, Sulgiye; Fuentes, Antonio F.; Park, Changyong; Ewing, Rodney C.; Mao, Wendy L.

    2017-05-22

    Strain engineering is a promising method for next-generation materials processing techniques. Here, we use mechanical milling and annealing followed by compression in diamond anvil cell to tailor the intrinsic and extrinsic strain in pyrochlore, Dy2Ti2O7 and Dy2Zr2O7. Raman spectroscopy, X-ray pair distribution function analysis, and X-ray diffraction were used to characterize atomic order over short-, medium-, and long-range spatial scales, respectively, under ambient conditions. Raman spectroscopy and X-ray diffraction were further employed to interrogate the material in situ at high pressure. High-pressure behavior is found to depend on the species and concentration of defects in the sample at ambient conditions. Overall, we show that defects can be engineered to lower the phase transformation onset pressure by ~50% in the ordered pyrochlore Dy2Zr2O7, and lower the phase transformation completion pressure by ~20% in the disordered pyrochlore Dy2Zr2O7. These improvements are achieved without significantly sacrificing mechanical integrity, as characterized by bulk modulus.

  15. 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.

  16. Advanced Diagnostics for High Pressure Spray Combustion.

    Energy Technology Data Exchange (ETDEWEB)

    Skeen, Scott A.; Manin, Julien Luc; Pickett, Lyle M.

    2014-06-01

    The development of accurate predictive engine simulations requires experimental data to both inform and validate the models, but very limited information is presently available about the chemical structure of high pressure spray flames under engine- relevant conditions. Probing such flames for chemical information using non- intrusive optical methods or intrusive sampling techniques, however, is challenging because of the physical and optical harshness of the environment. This work details two new diagnostics that have been developed and deployed to obtain quantitative species concentrations and soot volume fractions from a high-pressure combusting spray. A high-speed, high-pressure sampling system was developed to extract gaseous species (including soot precursor species) from within the flame for offline analysis by time-of-flight mass spectrometry. A high-speed multi-wavelength optical extinction diagnostic was also developed to quantify transient and quasi-steady soot processes. High-pressure sampling and offline characterization of gas-phase species formed following the pre-burn event was accomplished as well as characterization of gas-phase species present in the lift-off region of a high-pressure n-dodecane spray flame. For the initial samples discussed in this work several species were identified, including polycyclic aromatic hydrocarbons (PAH); however, quantitative mole fractions were not determined. Nevertheless, the diagnostic developed here does have this capability. Quantitative, time-resolved measurements of soot extinction were also accomplished and the novel use of multiple incident wavelengths proved valuable toward characterizing changes in soot optical properties within different regions of the spray flame.

  17. High-pressure microhydraulic actuator

    Science.gov (United States)

    Mosier, Bruce P [San Francisco, CA; Crocker, Robert W [Fremont, CA; Patel, Kamlesh D [Dublin, CA

    2008-06-10

    Electrokinetic ("EK") pumps convert electric to mechanical work when an electric field exerts a body force on ions in the Debye layer of a fluid in a packed bed, which then viscously drags the fluid. Porous silica and polymer monoliths (2.5-mm O.D., and 6-mm to 10-mm length) having a narrow pore size distribution have been developed that are capable of large pressure gradients (250-500 psi/mm) when large electric fields (1000-1500 V/cm) are applied. Flowrates up to 200 .mu.L/min and delivery pressures up to 1200 psi have been demonstrated. Forces up to 5 lb-force at 0.5 mm/s (12 mW) have been demonstrated with a battery-powered DC-DC converter. Hydraulic power of 17 mW (900 psi@ 180 uL/min) has been demonstrated with wall-powered high voltage supplies. The force and stroke delivered by an actuator utilizing an EK pump are shown to exceed the output of solenoids, stepper motors, and DC motors of similar size, despite the low thermodynamic efficiency.

  18. Nuclear magnetic resonance studies at high pressures

    International Nuclear Information System (INIS)

    Jonas, J.

    1980-01-01

    Recent advances in the field of NMR spectroscopy at high pressure are reviewed. After a brief discussion of two novel experimental techniques, the main focus of this review is on several specific studies which illustrate the versatility and power of this high pressure field. Experimental aspects of NMR measurements at high pressure and high temperature and the techniques for the high resolution NMR spectroscopy at high pressure are discussed. An overview of NMR studies of the dynamic structure of simple polyatomic liquids and hydrogen bonded liquids is followed by a discussion of high resolution spectroscopy at high pressure. Examples of NMR studies of disordered organic solids and polymers conclude the review. (author)

  19. Sealing of rotary drums for operation under pressurized conditions

    International Nuclear Information System (INIS)

    Shirvani, M.; Khanof, M. H.; Yousefi, M. R.; Sadighi, S.

    2006-01-01

    In practice, rotary drums are always designed for operation under vacuum conditions. In this paper, a novel technique is proposed for sealing the rotary drums under pressurized conditions. The proposed system is based on applying a secondary pressurized volume around the leaking gap of the drum. By controlling the pressure of this volume above the pressure of the drum, it will be possible to prevent from any leakage of gases to the ambient. The objective of a controller in this system is that the pressure of secondary volume be kept above the pressure of the drum in spite of the disturbances which may be exerted on the system by the wind outside the drum. The control system is also required to trace the variations in the drum pressure with the least fluctuations in the pressure difference among the drum and the volume

  20. Test report: Preliminary tests for the High Flux Reactor: Experimental determination of flow redistribution conditions at pressures between 4 and 5 kg/cm2 abs in a rectangular channel 2 mm thick and 60 cm long

    International Nuclear Information System (INIS)

    Schleisiek, K.; Dumaine, J.C.

    1989-01-01

    In the context of safety research for the OSIRIS reactor, tests have been performed on the Super BOB cell with a view to determining experimentally the internal characteristics (or ''S'' curves) of a channel with a rectangular heating cross-section 2 x 38 mm and 600 mm long. During these tests the maximum pressure at the channel exit was brought to 3 kg/cm 2 abs. The pressurization level in the High Flux Reactor will be higher. That is why tests have been carried out at maximum pressure of 5 kg/cm 2 abs allowable on the ''super BOB'' loop without modifying it. The first objective of this test series was to determine the ''S'' curves and the exchange coefficients experimentally. This document discusses the test conditions and test results

  1. DASH diet to lower high blood pressure

    Science.gov (United States)

    ... patientinstructions/000770.htm DASH diet to lower high blood pressure To use the sharing features on this page, ... Hypertension. The DASH diet can help lower high blood pressure and cholesterol and other fats in your blood. ...

  2. What Is High Blood Pressure Medicine?

    Science.gov (United States)

    ... a medicine calendar. • Set a reminder on your smartphone. What types of medicine may be prescribed? One ... High Blood Pressure Medicine? What are their side effects? For many people, high blood pressure medicine can ...

  3. High blood pressure - medicine-related

    Science.gov (United States)

    Drug-induced hypertension is high blood pressure caused by using a chemical substance or medicine. ... of the arteries There are several types of high blood pressure : Essential hypertension has no cause that can be ...

  4. High blood pressure and eye disease

    Science.gov (United States)

    ... this page: //medlineplus.gov/ency/article/000999.htm High blood pressure and eye disease To use the sharing features on this page, please enable JavaScript. High blood pressure can damage blood vessels in the retina . The ...

  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. Solid gas reaction phase diagram under high gas pressure

    International Nuclear Information System (INIS)

    Ishizaki, K.

    1992-01-01

    This paper reports that to evaluate which are the stable phases under high gas pressure conditions, a solid-gas reaction phase diagram under high gas pressure (HIP phase diagram) has been proposed by the author. The variables of the diagram are temperature, reactant gas partial pressure and total gas pressure. Up to the present time the diagrams have been constructed using isobaric conditions. In this work, the stable phases for a real HIP process were evaluated assuming an isochoric condition. To understand the effect of the total gas pressure on stability is of primary importance. Two possibilities were considered and evaluated, those are: the total gas pressure acts as an independent variable, or it only affects the fugacity values. The results of this work indicate that the total gas pressure acts as an independent variable, and in turn also affects the fugacity values

  7. High pressure metrology for industrial applications

    Science.gov (United States)

    Sabuga, Wladimir; Rabault, Thierry; Wüthrich, Christian; Pražák, Dominik; Chytil, Miroslav; Brouwer, Ludwig; Ahmed, Ahmed D. S.

    2017-12-01

    To meet the needs of industries using high pressure technologies, in traceable, reliable and accurate pressure measurements, a joint research project of the five national metrology institutes and the university was carried out within the European Metrology Research Programme. In particular, finite element methods were established for stress-strain analysis of elastic and nonlinear elastic-plastic deformation, as well as of contact processes in pressure-measuring piston-cylinder assemblies, and high-pressure components at pressures above 1 GPa. New pressure measuring multipliers were developed and characterised, which allow realisation of the pressure scale up to 1.6 GPa. This characterisation is based on research including measurements of material elastic constants by the resonant ultrasound spectroscopy, hardness of materials of high pressure components, density and viscosity of pressure transmitting liquids at pressures up to 1.4 GPa and dimensional measurements on piston-cylinders. A 1.6 GPa pressure system was created for operation of the 1.6 GPa multipliers and calibration of high pressure transducers. A transfer standard for 1.5 GPa pressure range, based on pressure transducers, was built and tested. Herewith, the project developed the capability of measuring pressures up to 1.6 GPa, from which industrial users can calibrate their pressure measurement devices for accurate measurements up to 1.5 GPa.

  8. High-Pressure Lightweight Thrusters

    Science.gov (United States)

    Holmes, Richard; McKechnie, Timothy; Shchetkovskiy, Anatoliy; Smirnov, Alexander

    2013-01-01

    Returning samples of Martian soil and rock to Earth is of great interest to scientists. There were numerous studies to evaluate Mars Sample Return (MSR) mission architectures, technology needs, development plans, and requirements. The largest propulsion risk element of the MSR mission is the Mars Ascent Vehicle (MAV). Along with the baseline solid-propellant vehicle, liquid propellants have been considered. Similar requirements apply to other lander ascent engines and reaction control systems. The performance of current state-ofthe- art liquid propellant engines can be significantly improved by increasing both combustion temperature and pressure. Pump-fed propulsion is suggested for a single-stage bipropellant MAV. Achieving a 90-percent stage propellant fraction is thought to be possible on a 100-kg scale, including sufficient thrust for lifting off Mars. To increase the performance of storable bipropellant rocket engines, a high-pressure, lightweight combustion chamber was designed. Iridium liner electrodeposition was investigated on complex-shaped thrust chamber mandrels. Dense, uniform iridium liners were produced on chamber and cylindrical mandrels. Carbon/carbon composite (C/C) structures were braided over iridium-lined mandrels and densified by chemical vapor infiltration. Niobium deposition was evaluated for forming a metallic attachment flange on the carbon/ carbon structure. The new thrust chamber was designed to exceed state-of-the-art performance, and was manufactured with an 83-percent weight savings. High-performance C/Cs possess a unique set of properties that make them desirable materials for high-temperature structures used in rocket propulsion components, hypersonic vehicles, and aircraft brakes. In particular, more attention is focused on 3D braided C/Cs due to their mesh-work structure. Research on the properties of C/Cs has shown that the strength of composites is strongly affected by the fiber-matrix interfacial bonding, and that weakening

  9. 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

  10. 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

  11. HIGH BLOOD PRESSURE: DOES THIS CONCERN ME?

    CERN Multimedia

    2007-01-01

    To find out, the Medical Service's nurses are organising A HIGH BLOOD PRESSURE SCREENING AND PREVENTION CAMPAIGN from Monday, 26th to Thursday, 29th March 2007 at the Infirmary - Building 57 - ground floor A blood pressure test, advice, information and, if necessary, referral for specialist medical treatment will be offered to any person working on the CERN site. High blood pressure is a silent threat to health. So come and get your blood pressure checked.

  12. HIGH BLOOD PRESSURE: DOES THIS CONCERN ME?

    CERN Multimedia

    2007-01-01

    To find out, the Medical Service's nurses are organising A HIGH BLOOD PRESSURE SCREENING AND PREVENTION CAMPAIGN from Monday, 26th to Thursday, 29th March 2007 at the Infirmary - Building 57 - ground floor A blood pressure test, advice, information and, if necessary, referral for specialist medical treatment will be offered to any person working on the CERN site. High blood pressure is a stealth threat to health. So come and get your blood pressure checked.

  13. High pressure effect for high-Tc superconductors

    International Nuclear Information System (INIS)

    Takahashi, Hiroki; Tomita, Takahiro

    2011-01-01

    A number of experimental and theoretical studies have been performed to understand the mechanism of high-T c superconductivity and to enhance T c . High-pressure techniques have played a very important role for these studies. In this paper, the high-pressure techniques and physical properties of high-T c superconductor under high pressure are presented. (author)

  14. Transportable, small high-pressure preservation vessel for cells

    International Nuclear Information System (INIS)

    Kamimura, N; Sotome, S; Shimizu, A; Nakajima, K; Yoshimura, Y

    2010-01-01

    We have previously reported that the survival rate of astrocytes increases under high-pressure conditions at 4 0 C. However, pressure vessels generally have numerous problems for use in cell preservation and transportation: (1) they cannot be readily separated from the pressurizing pump in the pressurized state; (2) they are typically heavy and expensive due the use of materials such as stainless steel; and (3) it is difficult to regulate pressurization rate with hand pumps. Therefore, we developed a transportable high-pressure system suitable for cell preservation under high-pressure conditions. This high-pressure vessel has the following characteristics: (1) it can be easily separated from the pressurizing pump due to the use of a cock-type stop valve; (2) it is small and compact, is made of PEEK and weighs less than 200 g; and (3) pressurization rate is regulated by an electric pump instead of a hand pump. Using this transportable high-pressure vessel for cell preservation, we found that astrocytes can survive for 4 days at 1.6 MPa and 4 0 C.

  15. Effects of aging on blood pressure variability in resting conditions

    NARCIS (Netherlands)

    Veerman, D. P.; Imholz, B. P.; Wieling, W.; Karemaker, J. M.; van Montfrans, G. A.

    1994-01-01

    The objective of this study was to determine the effect of aging on beat-to-beat blood pressure and pulse interval variability in resting conditions and to determine the effect of aging on the sympathetic and vagal influence on the cardiovascular system by power spectral analysis of blood pressure

  16. Extrapolation of bulk rock elastic moduli of different rock types to high pressure conditions and comparison with texture-derived elastic moduli

    Science.gov (United States)

    Ullemeyer, Klaus; Lokajíček, Tomás; Vasin, Roman N.; Keppler, Ruth; Behrmann, Jan H.

    2018-02-01

    In this study elastic moduli of three different rock types of simple (calcite marble) and more complex (amphibolite, micaschist) mineralogical compositions were determined by modeling of elastic moduli using texture (crystallographic preferred orientation; CPO) data, experimental investigation and extrapolation. 3D models were calculated using single crystal elastic moduli, and CPO measured using time-of-flight neutron diffraction at the SKAT diffractometer in Dubna (Russia) and subsequently analyzed using Rietveld Texture Analysis. To define extrinsic factors influencing elastic behaviour, P-wave and S-wave velocity anisotropies were experimentally determined at 200, 400 and 600 MPa confining pressure. Functions describing variations of the elastic moduli with confining pressure were then used to predict elastic properties at 1000 MPa, revealing anisotropies in a supposedly crack-free medium. In the calcite marble elastic anisotropy is dominated by the CPO. Velocities continuously increase, while anisotropies decrease from measured, over extrapolated to CPO derived data. Differences in velocity patterns with sample orientation suggest that the foliation forms an important mechanical anisotropy. The amphibolite sample shows similar magnitudes of extrapolated and CPO derived velocities, however the pattern of CPO derived velocity is closer to that measured at 200 MPa. Anisotropy decreases from the extrapolated to the CPO derived data. In the micaschist, velocities are higher and anisotropies are lower in the extrapolated data, in comparison to the data from measurements at lower pressures. Generally our results show that predictions for the elastic behavior of rocks at great depths are possible based on experimental data and those computed from CPO. The elastic properties of the lower crust can, thus, be characterized with an improved degree of confidence using extrapolations. Anisotropically distributed spherical micro-pores are likely to be preserved, affecting

  17. Bridge pressure flow scour for clear water conditions

    Science.gov (United States)

    2009-10-01

    The equilibrium scour at a bridge caused by pressure flow with critical approach velocity in clear-water simulation conditions was studied both analytically and experimentally. The flume experiments revealed that (1) the measured equilibrium scour pr...

  18. 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.)

  19. 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.

  20. High pressure gas reinjection unit

    Energy Technology Data Exchange (ETDEWEB)

    1976-03-01

    Nuovo Pignone has built for gas reinjection at Ekofisk the highest pressure injection unit to date: suction pressure 246 bar, discharge 647 bar, for 5.7 million cu m/day of natural gas, and driven by a GE MS 5001 gas turbine of 24,000 hp. The barrel-type compressor has been used already in Algeria at Hassi Messaoud. Full scale tests have shown that the unit is satisfactory; special attention being paid to the stability of the rotor. Air cooled heat exchangers were used in the test loop to cool the discharge gas; at Ekofisk, heat exchangers with sea water will be used. The valves in the test loop were of a special, low- noise type. Vibrations of the rotor system and changes in gas pressure monitored, showing that a pressure of 680 bars can be achieved without instability. Economic considerations lead to preference for rotary compressors driven by gas turbines for similar applications in the exploitation of oil fields. A graph of the characteristics of the unit is given.

  1. High-pressure boron hydride phases

    International Nuclear Information System (INIS)

    Barbee, T.W. III; McMahan, A.K.; Klepeis, J.E.; van Schilfgaarde, M.

    1997-01-01

    The stability of boron-hydrogen compounds (boranes) under pressure is studied from a theoretical point of view using total-energy methods. We find that the molecular forms of boranes known to be stable at ambient pressure become unstable at high pressure, while structures with extended networks of bonds or metallic bonding are energetically favored at high pressures. If such structures are metastable on return to ambient pressure, they would be energetic as well as dense hydrogen storage media. An AlH 3 -like structure of BH 3 is particularly interesting in that it may be accessible by high-pressure diamond anvil experiments, and should exhibit both second-order structural and metal-insulator transitions at lower pressures. copyright 1997 The American Physical Society

  2. 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).

  3. Moessbauer study of phase transitions under high hydrostatic pressures. 1

    International Nuclear Information System (INIS)

    Kapitanov, E.V.; Yakovlev, E.N.

    1979-01-01

    Experimental results of the hydrostatic pressure influence on Moessbauer spectrum parameters are obtained over the pressure range including the area of structural phase transition. A linear increase of the Moessbauer effect probability (recoilless fraction) is accompanied by a linear decrease of the electron density at tin nuclei within the pressure range foregoing the phase transition. The electric resistance and the recoilless fraction of the new phase of Mg 2 Sn are lower, but the electron density at tin nuclei is greater than the initial phase ones. Hydrostatic conditions allow to fix clearly the diphasic transition area and to determine the influence of the pressure on the Moessbauer line position and on the recoilless fraction of the high pressure phase. The phase transition heat Q = 415 cal mol -1 is calculated using recoilless fractions of the high and low pressure phases at 25 kbar. The present results are qualitatively and quantitatively different from the results, obtained at nonhydrostatic conditions. (author)

  4. High-pressure torsion of hafnium

    International Nuclear Information System (INIS)

    Edalati, Kaveh; Horita, Zenji; Mine, Yoji

    2010-01-01

    Pure Hf (99.99%) is processed by high-pressure torsion (HPT) under pressures of 4 and 30 GPa to form an ultrafine-grained structure with a gain size of ∼180 nm. X-ray diffraction analysis shows that, unlike Ti and Zr, no ω phase formation is detected after HPT processing even under a pressure of 30 GPa. A hydride formation is detected after straining at the pressure of 4 GPa. The hydride phase decomposes either by application of a higher pressure as 30 GPa or by unloading for prolong time after HPT processing. Microhardness, tensile and bending tests show that a high hardness (360 Hv) and an appreciable ductility (8%) as well as high tensile and bending strength (1.15 and 2.75 GPa, respectively) are achieved following the high-pressure torsion.

  5. Effects of the imposed pressure differential conditions on duoplasmatron performance

    International Nuclear Information System (INIS)

    Oztarhan, A.

    1988-01-01

    The duoplasmatron plasma source (D.P.T.) was modified to allow access to the arc discharge (to measure the discharge properties) and to vary independently the pressures in different volumes of the arc with the aim of seeing if this freedom would help in optimising the output. The duoplasmatron plasma source was operated under normal running condition (N.R.C.), positive imposed pressure differential condition (P.I.P.D.C.) and negative imposed pressure differential condition (N.I.P.D.C.) and the corresponding properties of the plasma output were measured. Running the duoplasmatron under P.I.P.D. condition did not seem to improve the output as compared to that under N.R.C. However, running the duoplasmatron under N.I.P.D. condition seemed to be advantageous as the output increased by about 30%. It was observed that the back pressure was critical in maintaining the arc and the gap pressure could be lowered much below the normal minimum (while the arc was on) if back pressure was kept above a critical value. The results showed that the effects of varying the dimensions of the intermediate electrode nozzle on the output could be understood in terms of the effect of changes in these dimensions on the relative pressures. An empirical expression for the effect of the pressure ratio was developed from the observations and compared with the experimental results. The reasons for various results can be related to the plasma emission mechanism. (author). 8 refs, 6 figs, 1 tab

  6. Managing Stress to Control High Blood Pressure

    Science.gov (United States)

    ... Aortic Aneurysm More Managing Stress to Control High Blood Pressure Updated:Jan 29,2018 The importance of stress ... This content was last reviewed October 2016. High Blood Pressure • Home • Get the Facts About HBP • Know Your ...

  7. Pyrolysis and gasification behavior of black liquor under pressurized conditions

    Energy Technology Data Exchange (ETDEWEB)

    Whitty, K

    1997-11-01

    The purpose of this study has been to enhance the understanding of the processes involved in pressurized black liquor gasification. Gasification is known to occur in three stages: drying, pyrolysis and char gasification. The work presented here focuses on the pyrolysis and gasification stages. Experiments were carried out primarily in two laboratory-scale reactors. A pressurized grid heater was used to study black liquor pyrolysis under pressurized conditions. Char yields and the fate of elements in the liquor, as well as the degree of liquor swelling, were measured in this device. A pressurized thermogravimetric reactor was used to measure the rate of the char gasification process under different temperatures and pressures and in various gas atmospheres. Pyrolysis experiments were also carried out in this device, and data on swelling behavior, char yields and component release were obtained 317 refs.

  8. High-pressure test loop design and application

    International Nuclear Information System (INIS)

    Burnette, R.D.; Graves, J.N.; Blair, P.G.; Baldwin, N.L.

    1980-07-01

    A high-pressure test loop (HPTL) has been constructed for the purpose of performing a number of chemistry experiments at simulated HTGR conditions of temperature, pressure, flow, and impurity content. The HPTL can be used to develop, modify, and verify computer codes for a variety of chemical processes involving gas phase transport in the reactor. Processes such as graphite oxidation, fission product transport, fuel reactions, purification systems, and dust entrainment can be studied at high pressure, which would largely eliminate difficulties in correlating existing laboratory data and reactor conditions

  9. High pressure injection of dimethyl ether

    Energy Technology Data Exchange (ETDEWEB)

    Glensvig, M.; Sorenson, S.C.; Abata, D.L.

    1997-08-01

    The purpose of this investigation was to achieve a better understanding of the fundamental spray behavior of DME (Dimenthyl Ether) using a standard diesel pump with pintle and hole nozzles. Fundamental spray behavior was characterized by determining fuel spray penetration and angle, atomization and evaporation. The influences of opening pressure, nozzle geometry and ambient pressure above and below the critical pressure of the fuel on the spray behavior were investigated. The influence of opening pressures on the spray characteristics for the hole nozzle was investigated. The results showed that for opening pressures of 120 bar and 180 bar the spray has a similar appearance. For the higher opening pressure (200 bar and 240 bar), the initial spray breaks up very rapidly giving a high initial spray angle. The opening pressure had little influence on spray penetration. The spray angle later in the injection increased as the opening pressure was decreased. Above the critical pressure, the spray from the hole nozzle had a more irregular shape. Penetration decreased and the spray angle increased above the critical pressure. Three pintle nozzles with different geometries and opening pressures were tested. The appearance of the three sprays were very similar. The sprays seemed to be more sharply pointed as the nozzle hole angle decreased. The nozzle with the 4 deg. hole nozzle angle and an opening pressure of 280 bar had the highest penetration and highest initial spray angle. The pintle nozzle with the 12 deg. hole nozzle angle and opening pressure of approx. 450 bar was tested above the critical ambient pressure. Penetration was very similar for injection above and below the critical ambient pressure, while the spray angle decreased for the spray above the critical ambient pressure. (au)

  10. High Pressure EVA Glove (HPEG), Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — Final Frontier Design's (FFD) High Pressure EVA Glove (HPEG) is a game changing technology enabling future exploration class space missions. The high operating...

  11. Techniques in high pressure neutron scattering

    CERN Document Server

    Klotz, Stefan

    2013-01-01

    Drawing on the author's practical work from the last 20 years, Techniques in High Pressure Neutron Scattering is one of the first books to gather recent methods that allow neutron scattering well beyond 10 GPa. The author shows how neutron scattering has to be adapted to the pressure range and type of measurement.Suitable for both newcomers and experienced high pressure scientists and engineers, the book describes various solutions spanning two to three orders of magnitude in pressure that have emerged in the past three decades. Many engineering concepts are illustrated through examples of rea

  12. 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.

  13. High-pressure mechanical instability in rocks.

    Science.gov (United States)

    Byerlee, J D; Brace, W F

    1969-05-09

    At a confining pressure of a few kilobars, deformation of many sedimentary rocks, altered mafic rocks, porous volcanic rocks, and sand is ductile, in that instabilities leading to audible elastic shocks are absent. At pressures of 7 to 10 kilobars, however, unstable faulting and stick-slip in certain of these rocks was observed. This high pressure-low temperature instability might be responsible for earthquakes in deeply buried sedimentary or volcanic sequences.

  14. 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

  15. Nucleation at high pressure I: Theoretical considerations.

    NARCIS (Netherlands)

    Luijten, C.C.M.; Dongen, van M.E.H.

    1999-01-01

    A theoretical approach is presented that accounts for the influence of high pressure background gases on the vapor-to-liquid nucleation process. The key idea is to treat the carrier gas pressure as a perturbation parameter that modifies the properties of the nucleating substance. Two important

  16. High-pressure differential scanning microcalorimeter.

    Science.gov (United States)

    Senin, A A; Dzhavadov, L N; Potekhin, S A

    2016-03-01

    A differential scanning microcalorimeter for studying thermotropic conformational transitions of biopolymers at high pressure has been designed. The calorimeter allows taking measurements of partial heat capacity of biopolymer solutions vs. temperature at pressures up to 3000 atm. The principles of operation of the device, methods of its calibration, as well as possible applications are discussed.

  17. 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...

  18. High-pressure phase transitions of strontianite

    Science.gov (United States)

    Speziale, S.; Biedermann, N.; Reichmann, H. J.; Koch-Mueller, M.; Heide, G.

    2015-12-01

    Strontianite (SrCO3) is isostructural to aragonite, a major high-pressure polymorph of calcite. Thus it is a material of interest to investigate the high-pressure phase behavior of aragonite-group minerals. SrCO3 is a common component of natural carbonates and knowing its physical properties at high pressures is necessary to properly model the thermodynamic properties of complex carbonates, which are major crustal minerals but are also present in the deep Earth [Brenker et al., 2007] and control carbon cycling in the Earth's mantle. The few available high-pressure studies of SrCO3 disagree regarding both pressure stability and structure of the post-aragonite phase [Lin & Liu, 1997; Ono et al., 2005; Wang et al. 2015]. To clarify such controversies we investigated the high-pressure behavior of synthetic SrCO3 by Raman spectroscopy. Using a diamond anvil cell we compressed single-crystals or powder of strontianite (synthesized at 4 GPa and 1273 K for 24h in a multi anvil apparatus), and measured Raman scattering up to 78 GPa. SrCO3 presents a complex high-pressure behavior. We observe mode softening above 20 GPa and a phase transition at 25 - 26.9 GPa, which we interpret due to the CO3 groups rotation, in agreement with Lin & Liu [1997]. The lattice modes in the high-pressure phase show dramatic changes which may indicate a change from 9-fold coordinated Sr to a 12-fold-coordination [Ono, 2007]. Our results confirm that the high-pressure phase of strontianite is compatible with Pmmn symmetry. References Brenker, F.E. et al. (2007) Earth and Planet. Sci. Lett., 260, 1; Lin, C.-C. & Liu, L.-G. (1997) J. Phys. Chem. Solids, 58, 977; Ono, S. et al. (2005) Phys. Chem. Minerals, 32, 8; Ono, S. (2007) Phys. Chem. Minerals, 34, 215; Wang, M. et al. (2015) Phys Chem Minerals 42, 517.

  19. Magnetic and Superconducting Materials at High Pressures

    Energy Technology Data Exchange (ETDEWEB)

    Struzhkin, Viktor V. [Carnegie Inst. of Washington, Washington, DC (United States)

    2015-03-24

    The work concentrates on few important tasks in enabling techniques for search of superconducting compressed hydrogen compounds and pure hydrogen, investigation of mechanisms of high-Tc superconductivity, and exploring new superconducting materials. Along that route we performed several challenging tasks, including discovery of new forms of polyhydrides of alkali metal Na at very high pressures. These experiments help us to establish the experimental environment that will provide important information on the high-pressure properties of hydrogen-rich compounds. Our recent progress in RIXS measurements opens a whole field of strongly correlated 3d materials. We have developed a systematic approach to measure major electronic parameters, like Hubbard energy U, and charge transfer energy Δ, as function of pressure. This technique will enable also RIXS studies of magnetic excitations in iridates and other 5d materials at the L edge, which attract a lot of interest recently. We have developed new magnetic sensing technique based on optically detected magnetic resonance from NV centers in diamond. The technique can be applied to study superconductivity in high-TC materials, to search for magnetic transitions in strongly correlated and itinerant magnetic materials under pressure. Summary of Project Activities; development of high-pressure experimentation platform for exploration of new potential superconductors, metal polyhydrides (including newly discovered alkali metal polyhydrides), and already known superconductors at the limit of static high-pressure techniques; investigation of special classes of superconducting compounds (high-Tc superconductors, new superconducting materials), that may provide new fundamental knowledge and may prove important for application as high-temperature/high-critical parameter superconductors; investigation of the pressure dependence of superconductivity and magnetic/phase transformations in 3d transition metal compounds, including

  20. High pressure processing of meat

    DEFF Research Database (Denmark)

    Grossi, Alberto; Christensen, Mette; Ertbjerg, Per

    the rheological properties of pork meat batters by inducing formation of protein gels. HP induced protein gels are suggested to be formed by high molecular weight myofibrillar protein aggregates and by peptides formed by lysosomal enzyme-induced cleavage of myofibrillar proteins. Perspectives: The data presented...

  1. Raman spectroscopy of triolein under high pressures

    Science.gov (United States)

    Tefelski, D. B.; Jastrzębski, C.; Wierzbicki, M.; Siegoczyński, R. M.; Rostocki, A. J.; Wieja, K.; Kościesza, R.

    2010-03-01

    This article presents results of the high pressure Raman spectroscopy of triolein. Triolein, a triacylglyceride (TAG) of oleic acid, is an unsaturated fat, present in natural oils such as olive oil. As a basic food component and an energy storage molecule, it has considerable importance for food and fuel industries. To generate pressure in the experiment, we used a high-pressure cylindrical chamber with sapphire windows, presented in (R.M. Siegoczyński, R. Kościesza, D.B. Tefelski, and A. Kos, Molecular collapse - modification of the liquid structure induced by pressure in oleic acid, High Press. Res. 29 (2009), pp. 61-66). Pressure up to 750 MPa was applied. A Raman spectrometer in "macro"-configuration was employed. Raman spectroscopy provides information on changes of vibrational modes related to structural changes of triolein under pressure. Interesting changes in the triglyceride C‒H stretching region at 2650-3100 cm-1 were observed under high-pressures. Changes were also observed in the ester carbonyl (C˭ O) stretching region 1700-1780 cm-1 and the C‒C stretching region at 1050-1150 cm-1. The overall luminescence of the sample decreased under pressure, making it possible to set longer spectrum acquisition time and obtain more details of the spectrum. The registered changes suggest that the high-pressure solid phase of triolein is organized as β-polymorphic, as was reported in (C. Akita, T. Kawaguchi, and F. Kaneko, Structural study on polymorphism of cis-unsaturated triacylglycerol: Triolein, J. Phys. Chem. B 110 (2006), pp. 4346-4353; E. Da Silva and D. Rousseau, Molecular order and thermodynamics of the solid-liquid transition in triglycerides via Raman spectroscopy, Phys. Chem. Chem. Phys. 10 (2008), pp. 4606-4613) (with temperature-induced phase transitions). The research has shown that Raman spectroscopy in TAGs under pressure reveals useful information about its structural changes.

  2. High pressure semiconductor physics I

    CERN Document Server

    Willardson, R K; Paul, William; Suski, Tadeusz

    1998-01-01

    Since its inception in 1966, the series of numbered volumes known as Semiconductors and Semimetals has distinguished itself through the careful selection of well-known authors, editors, and contributors. The "Willardson and Beer" Series, as it is widely known, has succeeded in publishing numerous landmark volumes and chapters. Not only did many of these volumes make an impact at the time of their publication, but they continue to be well-cited years after their original release. Recently, Professor Eicke R. Weber of the University of California at Berkeley joined as a co-editor of the series. Professor Weber, a well-known expert in the field of semiconductor materials, will further contribute to continuing the series' tradition of publishing timely, highly relevant, and long-impacting volumes. Some of the recent volumes, such as Hydrogen in Semiconductors, Imperfections in III/V Materials, Epitaxial Microstructures, High-Speed Heterostructure Devices, Oxygen in Silicon, and others promise indeed that this tra...

  3. Modeling High Pressure Micro Hollow Cathode Discharges

    National Research Council Canada - National Science Library

    Boeuf, Jean-Pierre; Pitchford, Leanne

    2004-01-01

    This report results from a contract tasking CPAT as follows: The Grantee will perform theoretical modeling of point, surface, and volume high-pressure plasmas created using Micro Hollow Cathode Discharge sources...

  4. Foaming Glass Using High Pressure Sintering

    DEFF Research Database (Denmark)

    Østergaard, Martin Bonderup; Petersen, Rasmus Rosenlund; König, Jakob

    Foam glass is a high added value product which contributes to waste recycling and energy efficiency through heat insulation. The foaming can be initiated by a chemical or physical process. Chemical foaming with aid of a foaming agent is the dominant industrial process. Physical foaming has two...... to expand. After heat-treatment foam glass can be obtained with porosities of 80–90 %. In this study we conduct physical foaming of cathode ray tube (CRT) panel glass by sintering under high pressure (5-25 MPa) using helium, nitrogen, or argon at 640 °C (~108 Pa s). Reheating a sample in a heating...... variations. One way is by saturation of glass melts with gas. The other involves sintering of powdered glass under a high gas pressure resulting in glass pellets with high pressure bubbles entrapped. Reheating the glass pellets above the glass transition temperature under ambient pressure allows the bubbles...

  5. Preeclampsia and High Blood Pressure During Pregnancy

    Science.gov (United States)

    ... Gynecologists f AQ FREQUENTLY ASKED QUESTIONS FAQ034 PREGNANCY Preeclampsia and High Blood Pressure During Pregnancy • What is ... is chronic hypertension during pregnancy managed? • What is preeclampsia? • When does preeclampsia occur? • What causes preeclampsia? • What ...

  6. Teaming Up Against High Blood Pressure

    Centers for Disease Control (CDC) Podcasts

    This podcast is based on the September 2012 CDC Vital Signs report. A team-based approach by patients, health care systems, and health care providers is one of the best ways to treat uncontrolled high blood pressure.

  7. High-pressure portable pneumatic drive unit.

    Science.gov (United States)

    Hete, B F; Savage, M; Batur, C; Smith, W A; Golding, L A; Nosé, Y

    1989-12-01

    The left ventricular assist device (LVAD) of the Cleveland Clinic Foundation (CCF) is a single-chamber assist pump, driven by a high-pressure pneumatic cylinder. A low-cost, portable driver that will allow cardiac care patients, with a high-pressure pneumatic ventricle assist, more freedom of movement has been developed. The compact and light-weight configuration can provide periods of 2 h of freedom from a fixed position driver and does not use exotic technology.

  8. High Pressure Physics at Brigham Young University

    Science.gov (United States)

    Decker, Daniel

    2000-09-01

    I will discuss the high pressure research of Drs. J. Dean Barnett, Daniel L. Decker and Howard B. Vanfleet of the department of Physics and Astronomy at Brigham Young University and their many graduate students. I will begin by giving a brief history of the beginning of high pressure research at Brigham Young University when H. Tracy Hall came to the University from General Elecrtric Labs. and then follow the work as it progressed from high pressure x-ray diffraction experiments, melting curve measurements under pressure to pressure effects on tracer diffusion and Mossbauer effect spectra. This will be followed by showing the development of pressure calibration techniques from the Decker equation of state of NaCl to the ruby fluorescence spectroscopy and a short discussion of using a liquid cell for hydrostatic measurements and temperature control for precision high pressure measurements. Then I will conclude with a description of thermoelectric measuremnts, critical phenomena at the magnetic Curie point, and the tricritical point of BaTiO_3.

  9. High-pressure phase transition in Ho2O3

    International Nuclear Information System (INIS)

    Lonappan, Dayana; Shekar, N.V. Chandra; Ravindran, T.R.; Sahu, P. Ch.

    2010-01-01

    High-pressure X-ray diffraction and Raman studies on holmium sesquioxide (Ho 2 O 3 ) have been carried out up to a pressure of ∼17 GPa in a diamond-anvil cell at room temperature. Holmium oxide, which has a cubic or bixbyite structure under ambient conditions, undergoes an irreversible structural phase transition at around 9.5 GPa. The high-pressure phase has been identified to be low symmetry monoclinic type. The two phases coexist to up to about 16 GPa, above which the parent phase disappears. The high-pressure laser-Raman studies have revealed that the prominent Raman band ∼370 cm -1 disappears around the similar transition pressure. The bulk modulus of the parent phase is reported.

  10. Particle behavior and char burnout mechanisms under pressurized combustion conditions

    Energy Technology Data Exchange (ETDEWEB)

    Bauer, C.M.; Spliethoff, H.; Hein, K.R.G.

    1999-07-01

    Combined cycle systems with coal-fired gas turbines promise highest cycle efficiencies for this fuel. Pressurized pulverized coal combustion, in particular, yields high cycle efficiencies due to the high flue gas temperatures possible. The main problem, however, is to ensure a flue gas clean enough to meet the high gas turbine standards with a dirty fuel like coal. On the one hand, a profound knowledge of the basic chemical and physical processes during fuel conversion under elevated pressures is required whereas on the other hand suitable hot gas cleaning systems need to be developed. The objective of this work was to provide experimental data to enable a detailed description of pressurized coal combustion processes. A series of experiments were performed with two German hvb coals, Ensdorf and Goettelborn, and one German brown coal, Garzweiler, using a semi-technical scale pressurized entrained flow reactor. The parameters varied in the experiments were pressure, gas temperature and bulk gas oxygen concentration. A two-color pyrometer was used for in-situ determination of particle surface temperatures and particle sizes. Flue gas composition was measured and solid residue samples taken and subsequently analyzed. The char burnout reaction rates were determinated varying the parameters pressure, gas temperature and initial oxygen concentration. Variation of residence time was achieved by taking the samples at different points along the reaction zone. The most influential parameters on char burnout reaction rates were found to be oxygen partial pressure and fuel volatile content. With increasing pressure the burn-out reactions are accelerated and are mostly controlled by product desorption and pore diffusion being the limiting processes. The char burnout process is enhanced by a higher fuel volatile content.

  11. Design principles for high-pressure force fields: Aqueous TMAO solutions from ambient to kilobar pressures.

    Science.gov (United States)

    Hölzl, Christoph; Kibies, Patrick; Imoto, Sho; Frach, Roland; Suladze, Saba; Winter, Roland; Marx, Dominik; Horinek, Dominik; Kast, Stefan M

    2016-04-14

    Accurate force fields are one of the major pillars on which successful molecular dynamics simulations of complex biomolecular processes rest. They have been optimized for ambient conditions, whereas high-pressure simulations become increasingly important in pressure perturbation studies, using pressure as an independent thermodynamic variable. Here, we explore the design of non-polarizable force fields tailored to work well in the realm of kilobar pressures--while avoiding complete reparameterization. Our key is to first compute the pressure-induced electronic and structural response of a solute by combining an integral equation approach to include pressure effects on solvent structure with a quantum-chemical treatment of the solute within the embedded cluster reference interaction site model (EC-RISM) framework. Next, the solute's response to compression is taken into account by introducing pressure-dependence into selected parameters of a well-established force field. In our proof-of-principle study, the full machinery is applied to N,N,N-trimethylamine-N-oxide (TMAO) in water being a potent osmolyte that counteracts pressure denaturation. EC-RISM theory is shown to describe well the charge redistribution upon compression of TMAO(aq) to 10 kbar, which is then embodied in force field molecular dynamics by pressure-dependent partial charges. The performance of the high pressure force field is assessed by comparing to experimental and ab initio molecular dynamics data. Beyond its broad usefulness for designing non-polarizable force fields for extreme thermodynamic conditions, a good description of the pressure-response of solutions is highly recommended when constructing and validating polarizable force fields.

  12. Holographic interferometry of high pressure

    International Nuclear Information System (INIS)

    McIlwain, M.E.

    1987-01-01

    Measurements in turbulent flows have been historically performed using various types of probes and optical diagnostic methods. In general, probes suffer from plasma perturbation effects and are single point determination methods. Optical methods appear to be better suited to determinations in turbulent flows, however interpretation of the resulting data can often be complex. Methods such as laser Doppler anemometry, which relies on entrained particles, suffers from the fact that particles small enough to be swept along by the plasma are usually melted or sublimed in the plasma. Light refraction or diffraction methods such as shadow photography, interferometry, and holography have also been used to observe plasma flows. These methods typically suffer from the difficulty of interpreting line of sight images and obtaining quantitative data. A new method based on multi-pass holographic interferometry will be discussed. This method has certain advantages which can significantly simplify the complexity of line of sight interferometry image deconvolution. When the method employs high speed cinematography, time resolved images of the plasma flow can be obtained. This method has been applied to both transferred and non-transferred arcs and various types of DC-plasma torch produced jets. These studies and conclusions as to the usefulness of the technique are presented

  13. On high-pressure melting of tantalum

    Science.gov (United States)

    Luo, Sheng-Nian; Swift, Damian C.

    2007-01-01

    The issues related to high-pressure melting of Ta are discussed within the context of diamond-anvil cell (DAC) and shock wave experiments, theoretical calculations and common melting models. The discrepancies between the extrapolations of the DAC melting curve and the melting point inferred from shock wave experiments, cannot be reconciled either by superheating or solid-solid phase transition. The failure to reproduce low-pressure DAC melting curve by melting models such as dislocation-mediated melting and the Lindemann law, and molecular dynamics and quantum mechanics-based calculations, undermines their predictions at moderate and high pressures. Despite claims to the contrary, the melting curve of Ta (as well as Mo and W) remains inconclusive at high pressures.

  14. 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

  15. 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.

  16. Screening of hydrogen storage media applying high pressure thermogravimetry

    DEFF Research Database (Denmark)

    Bentzen, J.J.; Pedersen, Allan Schrøder; Kjøller, J.

    2001-01-01

    A number of commercially available hydride-forming alloys of the MmNi5–xSnx (Mm=mischmetal, a mixture of lanthanides) type were examined using a high pressure, high temperature microbalance,scanning electron microscopy and X-ray diffraction. Activation conditions, reversible storage capacity...

  17. Radioresistance increase in polymers at high pressures

    International Nuclear Information System (INIS)

    Milinchuk, V.; Kirjukhin, V.; Klinshpont, E.

    1977-01-01

    The effect was studied of very high pressures ranging within 100 and 2,700 MPa on the radioresistance of polytetrafluoroethylene, polypropylene and polyethylene in gamma irradiation. For experiments industrial polymers in the shape of blocks, films and fibres were used. It is shown that in easily breakable polymers, such as polytetrafluoroethylene and polypropylene 1.3 to 2 times less free radicals are formed as a result of gamma irradiation and a pressure of 150 MPa than at normal pressure. The considerably reduced radiation-chemical formation of radicals and the destruction suppression by cross-linking in polymers is the evidence of the polymer radioresistance in irradiation at high pressures. (J.B.)

  18. 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

  19. observed by high pressure NMR and NQR

    Indian Academy of Sciences (India)

    Akogun, Hyogo 678-1297, Japan. ∗. Email: kohara@sci.himeji tech.ac.jp. Abstract. NMR and NQR studies on two interesting systems (URu2Si2, CeTIn5) were performed under high pressure. (1) URu2Si2: In the pressure range 3.0 to 8.3 kbar, we have observed new 29Si. NMR signals arising from the antiferromagnetic ...

  20. Calculation of cooling tower plumes for high pressure wintry situations

    International Nuclear Information System (INIS)

    Gassmann, F.; Tinguely, M.; Haschke, D.

    1982-12-01

    The diffusion of the plumes of the projected nuclear power plants at Kaiseraugst and Schwoerstadt, during high pressure wintry conditions, has been examined using a mathematical model to simulate the plumes. For these calculations, microaerological measurements were made in the proximity of Kaiseraugst and Schwoerstadt. These give a typical image of the weather during high pressure wintry conditions, which is normally associated with an inversion, sometimes strong, at a low height. Dry cooling towers with natural draught, which offer an alternative solution to the wet cooling towers proposed for Kasieraugst, are examined equally. (Auth./G.T.H.)

  1. High pressure, high current, low inductance, high reliability sealed terminals

    Science.gov (United States)

    Hsu, John S [Oak Ridge, TN; McKeever, John W [Oak Ridge, TN

    2010-03-23

    The invention is a terminal assembly having a casing with at least one delivery tapered-cone conductor and at least one return tapered-cone conductor routed there-through. The delivery and return tapered-cone conductors are electrically isolated from each other and positioned in the annuluses of ordered concentric cones at an off-normal angle. The tapered cone conductor service can be AC phase conductors and DC link conductors. The center core has at least one service conduit of gate signal leads, diagnostic signal wires, and refrigerant tubing routed there-through. A seal material is in direct contact with the casing inner surface, the tapered-cone conductors, and the service conduits thereby hermetically filling the interstitial space in the casing interior core and center core. The assembly provides simultaneous high-current, high-pressure, low-inductance, and high-reliability service.

  2. 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.

  3. High-pressure oxidation of methane

    NARCIS (Netherlands)

    Hashemi, Hamid; Christensen, Jakob M.; Gersen, Sander; Levinsky, Howard; Klippenstein, Stephen J.; Glarborg, Peter

    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

  4. High pressure synthesis of bismuth disulfide

    DEFF Research Database (Denmark)

    Søndergaard-Pedersen, Simone; Nielsen, Morten Bormann; Bremholm, Martin

    In this research the BiS2 compound was synthesized by a high pressure and high temperature method using a multi-anvil large volume press and the structure was solved by single crystal diffraction. The structure contains Bi atoms in distorted square-based pyramidal coordination to five surrounding...

  5. 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

  6. 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

  7. 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

  8. Pressure indication during knocking conditions; Druckindizierung bei klopfender Verbrennung

    Energy Technology Data Exchange (ETDEWEB)

    Bertola, A.; Stadler, J.; Walter, T.; Wolfer, P. [Kistler Instrumente AG Winterthur (Switzerland); Gossweiler, C. [Fachhochschule Nordwestschweiz ITFE (Switzerland); Rothe, M. [Karlsruhe Univ. (Germany). Inst. fuer Kolbenmaschinen

    2006-07-01

    Depending on its frequency and intensity, knocking combustion can cause engine damage due to excessive thermal or mechanical stress on components. During knocking combustion, the cylinder pressure signal is overlaid with high-frequency pressure oscillations. Reliable detection of the knock timing and quantification of the knock intensity based on local measurement of the cylinder pressure demand for particular care, especially when it comes to selecting and adapting the sensor technology and also during the evaluation process using customary knock analysis methods. This publication examines various types of cylinder pressure sensors, how they are installed in the combustion chamber, the effect of sensor positioning and assesses them with regard to accuracy. Finally, on the basis of the test results, recommendations are given for selecting sensors and adapting them within the combustion chamber. A crucial factor for pressure measurement during knocking combustion is the sensor position within the combustion chamber. The sensor type is of secondary importance; at most, cavities between the combustion chamber and the sensor may influence the measuring signal. To assess the sensitivity of the knock evaluation algorithms to various mounting positions and sensor types, it is advisable to carry out comparative measurements between different sensor positions and the measuring spark plug. (orig.)

  9. High pressure freon decontamination of remote equipment

    International Nuclear Information System (INIS)

    Wilson, C.E.

    1987-01-01

    A series of decontamination tests using high pressure FREON 113 was conducted in the 200 Area of the Hanford site. The intent of these tests was to evaluate the effectiveness of FREON 113 in decontamination of manipulator components, tools, and equipment items contaminated with mixed fission products. The test results indicated that high pressure FREON 113 is very effective in removing fissile material from a variety of objects and can reduce both the quantity and the volume of the radioactive waste material presently being buried

  10. High pressure water jet cutting and stripping

    Science.gov (United States)

    Hoppe, David T.; Babai, Majid K.

    1991-01-01

    High pressure water cutting techniques have a wide range of applications to the American space effort. Hydroblasting techniques are commonly used during the refurbishment of the reusable solid rocket motors. The process can be controlled to strip a thermal protective ablator without incurring any damage to the painted surface underneath by using a variation of possible parameters. Hydroblasting is a technique which is easily automated. Automation removes personnel from the hostile environment of the high pressure water. Computer controlled robots can perform the same task in a fraction of the time that would be required by manual operation.

  11. High pressure water jet mining machine

    Science.gov (United States)

    Barker, Clark R.

    1981-05-05

    A high pressure water jet mining machine for the longwall mining of coal is described. The machine is generally in the shape of a plowshare and is advanced in the direction in which the coal is cut. The machine has mounted thereon a plurality of nozzle modules each containing a high pressure water jet nozzle disposed to oscillate in a particular plane. The nozzle modules are oriented to cut in vertical and horizontal planes on the leading edge of the machine and the coal so cut is cleaved off by the wedge-shaped body.

  12. Enhancement of anaerobic sludge digestion by high-pressure homogenization.

    Science.gov (United States)

    Zhang, Sheng; Zhang, Panyue; Zhang, Guangming; Fan, Jie; Zhang, Yuxuan

    2012-08-01

    To improve anaerobic sludge digestion efficiency, the effects of high-pressure homogenization (HPH) conditions on the anaerobic sludge digestion were investigated. The VS and TCOD were significantly removed with the anaerobic digestion, and the VS removal and TCOD removal increased with increasing the homogenization pressure and homogenization cycle number; correspondingly, the accumulative biogas production also increased with increasing the homogenization pressure and homogenization cycle number. The optimal homogenization pressure was 50 MPa for one homogenization cycle and 40 MPa for two homogenization cycles. The SCOD of the sludge supernatant significantly increased with increasing the homogenization pressure and homogenization cycle number due to the sludge disintegration. The relationship between the biogas production and the sludge disintegration showed that the accumulative biogas and methane production were mainly enhanced by the sludge disintegration, which accelerated the anaerobic digestion process and improved the methane content in the biogas. Copyright © 2012 Elsevier Ltd. All rights reserved.

  13. Dynamism or Disorder at High Pressures?

    Science.gov (United States)

    Angel, R. J.; Bismayer, U.; Marshall, W. G.

    2002-12-01

    Phase transitions in minerals at elevated temperatures typically involve dynamics as a natural consequence of the increase in thermal energy available to the system. Classic examples include quartz, cristobalite, and carbonates in which the high-temperature, high symmetry phase is dynamically disordered. This disorder has important thermodynamic consequences, including displacement and curvature of phase boundaries (e.g. calcite-aragonite). In other minerals such as clinopyroxenes and anorthite feldspar, the dynamic behaviour is restricted to the neighbourhood of the phase transition. The fundamental question is whether increasing pressure generally suppresses such dynamic behaviour (as in anorthite; Angel, 1988), or not. In the latter case it must be included in thermodynamic models of high-pressure phase equilibria and seismological modelling of the mantle; the potential dynamics and softening in stishovite may provide the critical observational constraint on the presence or otherwise of free silica in the lower mantle. We have continued to use the lead phosphate as a prototype ferroelastic in which to understand dynamic behaviour, simply because its dynamics and transition behaviour is far better characterised than any mineral. Furthermore, the phase transition is at a pressure where experimental difficulties do not dominate the experimental results. Our previous neutron diffraction study (Angel et al., 2001) revealed that some disorder, either dynamic or static, is retained in the high-symmetry, high-pressure phase just above the phase transition. New neutron diffraction data on the pure material now suggests that this disorder slowly decreases with increasing pressure until at twice the transition pressure it is ordered. Further data for doped material provides insights into the nature of this disorder. Angel (1988) Amer. Mineral. 73:1114. Angel et al (2001) J PhysC 13: 5353.

  14. Effect of high pressure on physicochemical properties of meat.

    Science.gov (United States)

    Buckow, Roman; Sikes, Anita; Tume, Ron

    2013-01-01

    The application of high pressure offers some interesting opportunities in the processing of muscle-based food products. It is well known that high-pressure processing can prolong the shelf life of meat products in addition to chilling but the pressure-labile nature of protein systems limits the commercial range of applications. High pressure can affect the texture and gel-forming properties of myofibrillar proteins and, hence, has been suggested as a physical and additive-free alternative to tenderize and soften or restructure meat and fish products. However, the rate and magnitude at which pressure and temperature effects take place in muscles are variable and depend on a number of circumstances and conditions that are still not precisely known. This review provides an overview of the current knowledge of the effects of high pressure on muscle tissue over a range of temperatures as it relates to meat texture, microstructure, color, enzymes, lipid oxidation, and pressure-induced gelation of myofibrillar proteins.

  15. Photoelectron spectroscopy under ambient pressure and temperature conditions

    International Nuclear Information System (INIS)

    Frank Ogletree, D.; Bluhm, Hendrik; Hebenstreit, Eleonore D.; Salmeron, Miquel

    2009-01-01

    We describe the development and applications of novel instrumentation for photoemission spectroscopy of solid or liquid surfaces in the presence of gases under ambient conditions of pressure and temperature. The new instrument overcomes the strong scattering of electrons in gases by the use of an aperture close to the surface followed by a differentially-pumped electrostatic lens system. In addition to the scattering problem, experiments in the presence of condensed water or other liquids require the development of special sample holders to provide localized cooling. We discuss the first two generations of Ambient Pressure PhotoEmission Spectroscopy (APPES) instruments developed at synchrotron light sources (ALS in Berkeley and BESSY in Berlin), with special focus on the Berkeley instruments. Applications to environmental science and catalytic chemical research are illustrated in two examples.

  16. High pressure photoinduced ring opening of benzene

    International Nuclear Information System (INIS)

    Ciabini, Lucia; Santoro, Mario; Bini, Roberto; Schettino, Vincenzo

    2002-01-01

    The chemical transformation of crystalline benzene into an amorphous solid (a-C:H) was induced at high pressure by employing laser light of suitable wavelengths. The reaction was forced to occur at 16 GPa, well below the pressure value (23 GPa) where the reaction normally occurs. Different laser sources were used to tune the pumping wavelength into the red wing of the first excited singlet state S 1 ( 1 B 2u ) absorption edge. Here the benzene ring is distorted, presenting a greater flexibility which makes the molecule unstable at high pressure. The selective pumping of the S 1 level, in addition to structural considerations, was of paramount importance to clarify the mechanism of the reaction

  17. Sounding experiments of high pressure gas discharge

    International Nuclear Information System (INIS)

    Biele, Joachim K.

    1998-01-01

    A high pressure discharge experiment (200 MPa, 5·10 21 molecules/cm 3 , 3000 K) has been set up to study electrically induced shock waves. The apparatus consists of the combustion chamber (4.2 cm 3 ) to produce high pressure gas by burning solid propellant grains to fill the electrical pump chamber (2.5 cm 3 ) containing an insulated coaxial electrode. Electrical pump energy up to 7.8 kJ at 10 kV, which is roughly three times of the gas energy in the pump chamber, was delivered by a capacitor bank. From the current-voltage relationship the discharge develops at rapidly decreasing voltage. Pressure at the combustion chamber indicating significant underpressure as well as overpressure peaks is followed by an increase of static pressure level. These data are not yet completely understood. However, Lorentz forces are believed to generate pinching with subsequent pinch heating, resulting in fast pressure variations to be propagated as rarefaction and shock waves, respectively. Utilizing pure axisymmetric electrode initiation rather than often used exploding wire technology in the pump chamber, repeatable experiments were achieved

  18. High Pressure Inactivation of HAV within Mussels

    Science.gov (United States)

    The potential of hepatitis A virus (HAV) to be inactivated within Mediterranean mussels (Mytilus galloprovincialis) and blue mussels (Mytilus edulis) by high pressure processing was evaluated. HAV was bioaccumulated within mussels to approximately 6-log10 PFU by exposure of mussels to HAV-contamina...

  19. Teaming Up Against High Blood Pressure

    Centers for Disease Control (CDC) Podcasts

    2012-09-04

    This podcast is based on the September 2012 CDC Vital Signs report. A team-based approach by patients, health care systems, and health care providers is one of the best ways to treat uncontrolled high blood pressure.  Created: 9/4/2012 by Centers for Disease Control and Prevention (CDC).   Date Released: 9/4/2012.

  20. High pressure and synchrotron radiation satellite workshop

    Energy Technology Data Exchange (ETDEWEB)

    Bass, J.; Guignot, N.; Morard, G.; Mezouar, M.; Andrault, D.; Bolfan-Casanova, N.; Sturhahn, W.; Daniel, I.; Reynard, B.; Simionovici, A.; Sanchez Valle, C.; Martinez, I.; Kantor, I.; Dubrovinsky, I.; Mccammon, C.; Dubrovinskaia, N.; Kurnosiv, A.; Kuznetsov, A.; Goncharenko, I.; Loubeyre, P.; Desgreniers, S.; Weck, G.; Yoo, C.S.; Iota, V.; Park, J.; Cynn, H.; Gorelli, F.; Toulemonde, P.; Machon, D.; Merlen, A.; San Miguel, A.; Amboage, M.; Aquilanti, G.; Mathon, O.; Pascarelli, S.; Itie, J.P.; Mcmillan, P.F.; Trapananti, A.; Di Cicco, A.; Panfilis, S. de; Filipponi, A.; Kreisel, J.; Bouvier, P.; Dkhil, B.; Chaabane, B.; Rosner, H.; Koudela, D.; Schwarz, U.; Handestein, A.; Hanfland, M.; Opahle, I.; Koepernik, K.; Kuzmin, M.; Mueller, K.H.; Mydosh, J.; Richter, M.; Hejny, C.; Falconi, S.; Lundegaard, L.F.; Mcmahon, M.I; Loa, I.; Syassen, K.; Wang, X.; Roth, H.; Lorenz, T.; Farber Daniel, I.; Antonangeli Daniele, I.; Krisch, M.; Badro, J.; Fiquet, G.; Occelli, F.; Mao, W.L.; Mao, H.K.; Eng, P.; Kao, C.C.; Shu, J.F.; Hemley, R.J.; Tse, J.S.; Yao, Y.; Deen, P.P.; Paolasini, I.; Braithwaite, D.; Kernavanois, N.; Lapertot, G.; Rupprecht, K.; Leupold, O.; Ponkratz, U.; Wortmann, G.; Beraud, A.; Krisch, M.; Farber, D.; Antonangeli, D.; Aracne, C.; Zarestky, J.L.; Mcqueeney, R.; Mathon, O.; Baudelet, F.; Decremps, F.; Itie, J.P.; Nataf, I.; Pascarelli, S.; Polian, A

    2006-07-01

    The workshop is dedicated to recent advances on science at high pressure at third generation synchrotron sources. A variety of experiments using synchrotron radiation techniques including X-ray diffraction, EXAFS (extended X-ray absorption fine structure), inelastic X-ray scattering, Compton scattering and Moessbauer spectroscopy of crystalline, liquid or amorphous samples, are reported. This document gathers the abstracts of the presentations.

  1. Study of ceramics sintering under high pressures

    International Nuclear Information System (INIS)

    Kunrath Neto, A.O.

    1990-01-01

    A systematic study was made on high pressure sintering of ceramics in order to obtain materials with controlled microstructure, which are not accessible by conventional methods. Some aspects with particular interest were: to achieve very low porosity, with fine grains; to produce dispersed metastable and denser phases which can act as toughening agents; the study of new possibilities for toughening enhancement. (author)

  2. Analysis of high-pressure safety valves

    NARCIS (Netherlands)

    Beune, A.

    2009-01-01

    In presently used safety valve sizing standards the gas discharge capacity is based on a nozzle flow derived from ideal gas theory. At high pressures or low temperatures real gas effects can no longer be neglected, so the discharge coefficient corrected for flow losses cannot be assumed constant

  3. High pressure studies of planetary matter

    International Nuclear Information System (INIS)

    Ross, M.

    1989-06-01

    Those materials which are of greatest interest to the physics of the deep planetary interiors are Fe, H 2 , He and the Ices. These are sufficiently diverse and intensively studied to offer an overview of present day high pressure research. 13 refs., 1 fig

  4. High pressure and synchrotron radiation satellite workshop

    International Nuclear Information System (INIS)

    Bass, J.; Guignot, N.; Morard, G.; Mezouar, M.; Andrault, D.; Bolfan-Casanova, N.; Sturhahn, W.; Daniel, I.; Reynard, B.; Simionovici, A.; Sanchez Valle, C.; Martinez, I.; Kantor, I.; Dubrovinsky, I.; Mccammon, C.; Dubrovinskaia, N.; Kurnosiv, A.; Kuznetsov, A.; Goncharenko, I.; Loubeyre, P.; Desgreniers, S.; Weck, G.; Yoo, C.S.; Iota, V.; Park, J.; Cynn, H.; Gorelli, F.; Toulemonde, P.; Machon, D.; Merlen, A.; San Miguel, A.; Amboage, M.; Aquilanti, G.; Mathon, O.; Pascarelli, S.; Itie, J.P.; Mcmillan, P.F.; Trapananti, A.; Di Cicco, A.; Panfilis, S. de; Filipponi, A.; Kreisel, J.; Bouvier, P.; Dkhil, B.; Chaabane, B.; Rosner, H.; Koudela, D.; Schwarz, U.; Handestein, A.; Hanfland, M.; Opahle, I.; Koepernik, K.; Kuzmin, M.; Mueller, K.H.; Mydosh, J.; Richter, M.; Hejny, C.; Falconi, S.; Lundegaard, L.F.; Mcmahon, M.I; Loa, I.; Syassen, K.; Wang, X.; Roth, H.; Lorenz, T.; Farber Daniel, I.; Antonangeli Daniele, I.; Krisch, M.; Badro, J.; Fiquet, G.; Occelli, F.; Mao, W.L.; Mao, H.K.; Eng, P.; Kao, C.C.; Shu, J.F.; Hemley, R.J.; Tse, J.S.; Yao, Y.; Deen, P.P.; Paolasini, I.; Braithwaite, D.; Kernavanois, N.; Lapertot, G.; Rupprecht, K.; Leupold, O.; Ponkratz, U.; Wortmann, G.; Beraud, A.; Krisch, M.; Farber, D.; Antonangeli, D.; Aracne, C.; Zarestky, J.L.; Mcqueeney, R.; Mathon, O.; Baudelet, F.; Decremps, F.; Itie, J.P.; Nataf, I.; Pascarelli, S.; Polian, A.

    2006-01-01

    The workshop is dedicated to recent advances on science at high pressure at third generation synchrotron sources. A variety of experiments using synchrotron radiation techniques including X-ray diffraction, EXAFS (extended X-ray absorption fine structure), inelastic X-ray scattering, Compton scattering and Moessbauer spectroscopy of crystalline, liquid or amorphous samples, are reported. This document gathers the abstracts of the presentations

  5. A hydronitrogen solid: high pressure ab initio evolutionary structure searches

    International Nuclear Information System (INIS)

    Hu Anguang; Zhang Fan

    2011-01-01

    High pressure ab initio evolutionary structure searches resulted in a hydronitrogen solid with a composition of (NH) 4 . The structure searches also provided two molecular isomers, ammonium azide (AA) and trans-tetrazene (TTZ) which were previously discovered experimentally and can be taken as molecular precursors for high pressure synthesis of the hydronitrogen solid. The computed pressure versus enthalpy diagram showed that the transformation pressure to the hydronitrogen solid is 36 GPa from AA and 75 GPa from TTZ. Its metastability was analyzed by the phonon dispersion spectrum and room-temperature vibrational density of state together with the transformation energy barrier back to molecular phases at 298 K. The predicted energy barrier of 0.21 eV/atom means that the proposed hydronitrogen solid should be very stable at ambient conditions. (fast track communication)

  6. High hydrostatic pressure processing of tropical fruits.

    Science.gov (United States)

    Lopes, Maria Lúcia M; Valente Mesquita, Vera L; Chiaradia, Ana Cristina N; Fernandes, Antônio Alberto R; Fernandes, Patricia M B

    2010-02-01

    Interest in the nonthermal method of high hydrostatic pressure (HHP) for food preservation has increased recently due to the possibility of inactivating microorganisms and enzymes while maintaining product sensorial and nutritional properties. This work deals with HHP use for the preservation of tropical fruit products. HHP is shown to be a practical approach to obtaining high-quality tropical fruit products that are both nutritive and safe.

  7. High pressure neutron powder diffraction at LANSCE

    International Nuclear Information System (INIS)

    Von Dreele, R.B.

    1994-01-01

    By making use of the recently developed ''Paris-Edinburgh'' high pressure cell, the author has successfully performed neutron powder experiments to 10GPa at ambient temperature. Results for the structural compression of the high Tc 1223-Hg superconductor to 9.2 GPa, the compression and possible hydrogen bond formation in brucite, Mg(OD) 2 , to 9.3 GPa, and the molecular reorientation in nitromethane to 5.5 GPa will be presented

  8. Effect of Fuel Injection and Mixing Characteristics on Pulse-Combustor Performance at High-Pressure

    Science.gov (United States)

    Yungster, Shaye; Paxson, Daniel E.; Perkins, Hugh D.

    2014-01-01

    Recent calculations of pulse-combustors operating at high-pressure conditions produced pressure gains significantly lower than those observed experimentally and computationally at atmospheric conditions. The factors limiting the pressure-gain at high-pressure conditions are identified, and the effects of fuel injection and air mixing characteristics on performance are investigated. New pulse-combustor configurations were developed, and the results show that by suitable changes to the combustor geometry, fuel injection scheme and valve dynamics the performance of the pulse-combustor operating at high-pressure conditions can be increased to levels comparable to those observed at atmospheric conditions. In addition, the new configurations can significantly reduce the levels of NOx emissions. One particular configuration resulted in extremely low levels of NO, producing an emission index much less than one, although at a lower pressure-gain. Calculations at representative cruise conditions demonstrated that pulse-combustors can achieve a high level of performance at such conditions.

  9. 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

  10. 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.

  11. Blue emitting organic semiconductors under high pressure

    DEFF Research Database (Denmark)

    Knaapila, Matti; Guha, Suchismita

    2016-01-01

    This review describes essential optical and emerging structural experiments that use high GPa range hydrostatic pressure to probe physical phenomena in blue-emitting organic semiconductors including π-conjugated polyfluorene and related compounds. The work emphasizes molecular structure and inter......This review describes essential optical and emerging structural experiments that use high GPa range hydrostatic pressure to probe physical phenomena in blue-emitting organic semiconductors including π-conjugated polyfluorene and related compounds. The work emphasizes molecular structure...... and intermolecular self-organization that typically determine transport and optical emission in π-conjugated oligomers and polymers. In this context, hydrostatic pressure through diamond anvil cells has proven to be an elegant tool to control structure and interactions without chemical intervention. This has been...... and intermolecular interactions on optical excitations, electron–phonon interaction, and changes in backbone conformations. This picture is connected to the optical high pressure studies of other π-conjugated systems and emerging x-ray scattering experiments from polyfluorenes which provides a structure-property map...

  12. The high-pressure behavior of bloedite

    DEFF Research Database (Denmark)

    Comodi, Paola; Nazzareni, Sabrina; Balic Zunic, Tonci

    2014-01-01

    High-pressure single-crystal synchrotron X‑ray diffraction was carried out on a single crystal of bloedite [Na2Mg(SO4)24H2O] compressed in a diamond-anvil cell. The volume-pressure data, collected up to 11.2 GPa, were fitted by a second- and a third-order Birch-Murnaghan equation of state (EOS....... Pressure decreases significantly the distortion of Na coordination. Up to 10 GPa, the donor-acceptor oxygen distances decrease significantly and the difference between the two water molecules decreases with an increase in the strengths of hydrogen bonds. At the same time, the bond lengths from Na and Mg...... to O atoms of the water molecules decrease faster than other bonds to these cations suggesting that there is a coupling between the Na-Ow and Mg-Ow bond strengths and the “hydrogen transfer” to acceptor O atoms....

  13. Pressurized thermal shock. Thermo-hydraulic conditions in the CNA-I reactor pressure vessel

    International Nuclear Information System (INIS)

    Ventura, Mirta A.; Rosso, Ricardo D.

    2002-01-01

    In this paper we analyze several reports issued by the Utility (Nucleo Electrica S.A.) and related to Reactor Pressure Vessel (RPV) phenomena in the CNA-I Nuclear Power Plant. These analyses are aimed at obtaining conclusions and establishing criteria ensuring the RPV integrity. Special attention was given to the effects ECCS cold-water injection at the RPV down-comer leading to pressurized thermal shock scenarios. The results deal with hypothetical primary system pipe breaks of different sizes, the inadvertent opening of the pressurizer safety valve, the double guillotine break of a live steam line in the containment and the inadvertent actuation pressurizer heaters. Modeling conditions were setup to represent experiments performed at the UPTF, under the hypothesis that they are representative of those that, hypothetically, may occur at the CNA-I. No system scaling analysis was performed, so this assertion and the inferred conclusions are no fully justified, at least in principle. The above mentioned studies, indicate that the RPV internal wall surface temperature will be nearly 40 degree. It was concluded that they allowed a better approximation of PTS phenomena in the RPV of the CNA-I. Special emphasis was made on the influence of the ECCS systems on the attained RPV wall temperature, particularly the low-pressure TJ water injection system. Some conservative hypothesis made, are discussed in this report. (author)

  14. 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.

  15. First-principles calculations of a high-pressure synthesized compound PtC

    International Nuclear Information System (INIS)

    Li Linyan; Yu Wen; Jin Changqing

    2005-01-01

    The first-principles density-functional method is used to study the recently high-pressure synthesized compound PtC. It is confirmed by our calculations that platinum carbide has a zinc-blende ground-state phase at zero pressure and that the rock-salt structure is a high-pressure phase. The theoretical transition pressure from zinc-blende to rock-salt structure is determined to be 52 GPa. Furthermore, our calculation shows the possibility that the PtC experimentally synthesized under high pressure conditions might undergo a transition from rock-salt to zinc-blende structure after a pressure quench to ambient conditions

  16. High pressure multiple shock response of aluminum

    International Nuclear Information System (INIS)

    Lawrence, R.J.; Asay, J.R.

    1977-01-01

    It is well known that both dynamic yield strength and rate-dependent material response exert direct influence on the development of surface and interface instabilities under conditions of strong shock loading. A detailed understanding of these phenomena is therefore an important aspect of the analysis of dynamic inertial confinement techniques which are being used in such applications as the generation of controlled thermonuclear fusion. In these types of applications the surfaces and interfaces under consideration can be subjected to cyclic loading characterized by shock pressures on the order of 100 GPa or more. It thus becomes important to understand how rate effects and material strength differ from the values observed in the low pressure regime where they are usually measured, as well as how they are altered by the loading history

  17. 7 CFR 58.219 - High pressure pumps and lines.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 3 2010-01-01 2010-01-01 false High pressure pumps and lines. 58.219 Section 58.219....219 High pressure pumps and lines. High pressure lines may be cleaned-in-place and shall be of such construction that dead ends, valves and the high pressure pumps can be disassembled for hand cleaning. The high...

  18. 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.

  19. High pressure {sup 31}P NMR spectroscopy on guanine nucleotides

    Energy Technology Data Exchange (ETDEWEB)

    Spoerner, Michael; Karl, Matthias; Lopes, Pedro; Hoering, Marcus; Loeffel, Karoline; Nuehs, Andrea; Adelsberger, Joseph; Kremer, Werner; Kalbitzer, Hans Robert, E-mail: hans-robert.kalbitzer@ur.de [University of Regensburg, Centre of Magnetic Resonance in Chemistry and Biomedicine, Institute of Biophysics and Physical Biochemistry (Germany)

    2017-01-15

    The {sup 31}P NMR pressure response of guanine nucleotides bound to proteins has been studied in the past for characterizing the pressure perturbation of conformational equilibria. The pressure response of the {sup 31}P NMR chemical shifts of the phosphate groups of GMP, GDP, and GTP as well as the commonly used GTP analogs GppNHp, GppCH{sub 2}p and GTPγS was measured in the absence and presence of Mg{sup 2+}-ions within a pressure range up to 200 MPa. The pressure dependence of chemical shifts is clearly non-linear. For all nucleotides a negative first order pressure coefficient B{sub 1} was determined indicating an upfield shift of the resonances with pressure. With exception of the α-phosphate group of Mg{sup 2+}·GMP and Mg{sup 2+}·GppNHp the second order pressure coefficients are positive. To describe the data of Mg{sup 2+}·GppCH{sub 2}p and GTPγS a Taylor expansion of 3rd order is required. For distinguishing pH effects from pressure effects a complete pH titration set is presented for GMP, as well as GDP and GTP in absence and presence of Mg{sup 2+} ions using indirect referencing to DSS under identical experimental conditions. By a comparison between high pressure {sup 31}P NMR data on free Mg{sup 2+}-GDP and Mg{sup 2+}-GDP in complex with the proto-oncogene Ras we demonstrate that pressure induced changes in chemical shift are clearly different between both forms.

  20. Leak Detection of High Pressure Feedwater Heater Using Empirical Models

    International Nuclear Information System (INIS)

    Lee, Song Kyu; Kim, Eun Kee; Heo, Gyun Young; An, Sang Ha

    2009-01-01

    Even small leak from tube side or pass partition within the high pressure feedwater heater (HPFWH) causes a significant deficiency in its performance. Plant operation under the HPFWH leak condition for long time will result in cost increase. Tube side leak within HPFWH can produce the high velocity jet of water and it can cause neighboring tube failures. However, most of plants are being operated without any information for internal leaks of HPFWH, even though it is prone to be damaged under high temperature and high pressure operating conditions. Leaks from tubes and/or pass partition of HPFWH occurred in many nuclear power plants, for example, Mihama PS-2, Takahama PS-2 and Point Beach Nuclear Plant Unit 1. If the internal leaks of HPFWH are monitored, the cost can be reduced by inexpensive repairs relative to loss in performance and moreover plant shutdown as well as further tube damages can be prevented

  1. 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

  2. Inspection technology for high pressure pipes

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jae H.; Lee, Jae C.; Eum, Heung S.; Choi, Yu R.; Moon, Soon S.; Jang, Jong H

    2000-02-01

    Various kinds of defects are likely to be occurred in the welds of high pressure pipes in nuclear power plants. Considering the recent accident of Zuruga nuclear power plant in Japan, reasonable policy is strongly requested for the high pressure pipe integrity. In this study, we developed the technologies to inspect pipe welds automatically. After development of scanning robot prototype in the first research year, we developed and implemented the algorithm of automatic tracking of the scanning robot along the weld line of the pipes. We use laser slit beam on weld area and capture the image using digital camera. Through processing of the captures image, we finally determine the weld line automatically. In addition, we investigated a new technology on micro systems for developing micro scanning robotic inspection of the pipe welds. The technology developed in this study is being transferred to the industry. (author)

  3. High pressure injection injuries: an overview.

    Science.gov (United States)

    Fialkov, J A; Freiberg, A

    1991-01-01

    Injuries resulting from the use of high pressure injectors and spray guns are relatively rare; however, the potential tissue damage caused by the injury as well as the extent of the injury itself may go unrecognized by the primary physician. The purpose of this paper is to inform the emergency physician of the nature and standard management of this type of injury. A basic understanding of the pathophysiology of the high pressure injection injury (HPII) is essential in avoiding the mistakes in management that have been reported in the literature. The emergency management of the HPII includes: evaluation and immobilization, tetanus and antimicrobial prophylaxis, supportive and resuscitative measures, analgesia, and minimizing the time to definitive surgical treatment.

  4. Stress concentration effects in high pressure components

    International Nuclear Information System (INIS)

    Aller, J.E.

    1990-01-01

    This paper examines the stress concentration effects of sideholes in thick walled, high pressure cylinders. It has been shown that the theoretical stress concentration factor at the intersection of a small crossbore in a closed end, thick walled cylinder varies between 3.0 and 4.0. Tests have shown that this effect can be greatly reduced in practice by carefully radiusing the bore intersection and autofrettaging the cylinder. It has also been shown that the minimum stress concentration factor occurs when the main bore and sidehole or crossbore have the same diameter, and the radius of the intersection is approximately equal to the sidehole radius. When the bore and sidehole intersection angle decreases from 90 degrees, the stress concentration factor increases significantly. Knowledge of these fundamental relationships can be used in maintaining, as well ad designing, high pressure equipment

  5. High Pressure Multicomponent Adsorption in Porous Media

    DEFF Research Database (Denmark)

    Shapiro, Alexander; Stenby, Erling Halfdan

    1999-01-01

    We analyse adsorption of a multicomponent mixture at high pressure on the basis of the potential theory of adsorption. The adsorbate is considered as a segregated mixture in the external field produced by a solid adsorbent. we derive an analytical equation for the thickness of a multicomponent fi...... close to a dew point. This equation (asymptotic adsorption equation, AAE) is a first order approximation with regard to the distance from a phase envelope....

  6. Elasticity of methane hydrate phases at high pressure

    Energy Technology Data Exchange (ETDEWEB)

    Beam, Jennifer; Yang, Jing; Liu, Jin [Department of Geological Sciences, Jackson School of Geosciences, The University of Texas at Austin, Austin, Texas 78712 (United States); Liu, Chujie [Laboratory of Seismology and Physics of Earth’s Interior, School of Earth and Space Sciences, University of Science and Technology of China, Hefei, Anhui 230026 (China); Lin, Jung-Fu, E-mail: afu@jsg.utexas.edu [Department of Geological Sciences, Jackson School of Geosciences, The University of Texas at Austin, Austin, Texas 78712 (United States); Center for High Pressure Science and Advanced Technology Research (HPSTAR), Shanghai 201203 (China)

    2016-04-21

    Determination of the full elastic constants (c{sub ij}) of methane hydrates (MHs) at extreme pressure-temperature environments is essential to our understanding of the elastic, thermodynamic, and mechanical properties of methane in MH reservoirs on Earth and icy satellites in the solar system. Here, we have investigated the elastic properties of singe-crystal cubic MH-sI, hexagonal MH-II, and orthorhombic MH-III phases at high pressures in a diamond anvil cell. Brillouin light scattering measurements, together with complimentary equation of state (pressure-density) results from X-ray diffraction and methane site occupancies in MH from Raman spectroscopy, were used to derive elastic constants of MH-sI, MH-II, and MH-III phases at high pressures. Analysis of the elastic constants for MH-sI and MH-II showed intriguing similarities and differences between the phases′ compressional wave velocity anisotropy and shear wave velocity anisotropy. Our results show that these high-pressure MH phases can exhibit distinct elastic, thermodynamic, and mechanical properties at relevant environments of their respective natural reservoirs. These results provide new insight into the determination of how much methane exists in MH reservoirs on Earth and on icy satellites elsewhere in the solar system and put constraints on the pressure and temperature conditions of their environment.

  7. Association of diarrhoea, poor hygiene and poor social conditions in childhood with blood pressure in adulthood.

    Science.gov (United States)

    Kauhanen, L; Lynch, J W; Lakka, H-M; Kauhanen, J; Smith, G D

    2010-05-01

    Previous research has suggested that dehydration in infancy may lead to high blood pressure in later life because of sodium retention. The purpose of this study was to examine the effect of poor hygiene of the child, poor social and poor housing conditions at home and diarrhoea in childhood as proxies for dehydration on high blood pressure in later life. Data were from a subset of participants in the Kuopio Ischaemic Heart Disease Risk Factor Study, a population-based cohort study in eastern Finland. Information on childhood factors was collected from school health records (n=952), from the 1930s to the 1950s. Adult data were obtained from baseline examinations of the Kuopio Ischaemic Heart Disease Risk Factor Study cohort (n=2682) in 1984-1989. Men who had poor hygiene in childhood had on average 4.07 mm Hg (95% CI 0.53 to 7.61) higher systolic blood pressure than men who had good or satisfactory hygiene in childhood in the age-adjusted analysis. Reports of diarrhoea were not associated with adult blood pressure. The authors' findings suggest that poor hygiene and living in poor social conditions in childhood are associated with higher systolic blood pressure in adulthood. Reported childhood diarrhoea did not explain the link between hygiene and high blood pressure in adulthood.

  8. High pressure phase transitions in Europous oxide

    International Nuclear Information System (INIS)

    Kremser, D.T.

    1982-01-01

    The pressure-volume relationship for EuO was investigated to 630 kilobars at room temperature with a diamond-anvil, high-pressure cell. Volumes were determined by x-ray diffraction; pressures were determined by the ruby R 1 fluorescence method. The preferred interpretation involves normal compression behavior for EuO, initially in the B1 (NaCl-type) structure, to about 280 kilobars. Between approx. =280 and approx. =350 kilobars a region of anomalous compressibility in which the volume drops continuously by approximately 2% is observed. A second-order electronic transition is proposed with the 6s band overlapping with the 4f levels, thereby reducing the volume of EuO without changing the structure. This is not a semiconductor-to-metal transition. In reflected light, this transition is correlated with a subtle and continuous change in color from brown-black to a light brown. The collapsed B1 phase (postelectronic transition) is stable between approx. =350 and approx. =400 kilobars. At about 400 kilobars the collapsed B1 structure transforms to the B2 (CsCl-type) structure, with a zero pressure-volume change of approximately 12 +/- 1.5%

  9. Improvement of the prediction of fluid pressure from the results of techno-geophysical studies under complex geological conditions

    Energy Technology Data Exchange (ETDEWEB)

    Aleksandrov, B.L.; Esipko, O.A.; Dakhkilgov, T.D.

    1981-12-01

    Results of statistical processing of the data of prediction of pore pressures in the course of well sinking, according to the material of oil field and geophysical investigations in different areas, are presented. Likewise, the errors of pressure prediction, their causes, geological models of series with anomalously high formation pressure, and methods for prediction of pore and formation pressures under different geological conditions are considered. 12 refs.

  10. 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.

  11. 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.

  12. Energy Systems High-Pressure Test Laboratory | Energy Systems Integration

    Science.gov (United States)

    Facility | NREL Energy Systems High-Pressure Test Laboratory Energy Systems High-Pressure Test Laboratory In the Energy Systems Integration Facility's High-Pressure Test Laboratory, researchers can safely test high-pressure hydrogen components. Photo of researchers running an experiment with a hydrogen fuel

  13. Behaviour of concrete containment under over-pressure conditions

    International Nuclear Information System (INIS)

    Atchison, R.J.; Asmis, G.J.K.; Campbell, F.R.

    1979-01-01

    The Atomic Energy Control Board of Canada initiated June, 1975, a major study of the behaviour of concrete containment under over-pressure conditions. Although extensive theoretical and experimental work has been carried out for thick-walled Prestressed Concrete Reactor Vessels (PCRV's), there is a want of information on the non-linear response of thin-walled structures typical of the CANDU, 600 MW(e) cylindrical/spherical, post-tensioned containment shells. The purpose of this paper is to provide an overview of the total program, to present the reasons behind the research contract, and the specification and implementation of the work. The results of the theoretical and experimental work and their implications with respect to Canadian Concrete Containment practice are discussed. This study is unique, and, as far as is known, has no world-wide precedence. (orig.)

  14. Hydrogen high pressure proportional drift detector

    International Nuclear Information System (INIS)

    Arefiev, A.; Balaev, A.

    1983-01-01

    The design and operation performances of a proportional drift detector PDD are described. High sensitivity of the applied PAD makes it possible to detect the neutron-proton elastic scattering in the energy range of recoil protons as low as 1 keV. The PDD is filled with hydrogen up to the pressure at 40 bars. High purity of the gas is maintained by a continuously operating purification system. The detector has been operating for several years in a neutron beam at the North Area of the CERN SPS

  15. Ignition during hydrogen release from high pressure into the atmosphere

    Science.gov (United States)

    Oleszczak, P.; Wolanski, P.

    2010-12-01

    The first investigations concerned with a problem of hydrogen jet ignition, during outflow from a high-pressure vessel were carried out nearly 40 years ago by Wolanski and Wojcicki. The research resulted from a dramatic accident in the Chorzow Chemical Plant Azoty, where the explosion of a synthesis gas made up of a mixture composed of three moles of hydrogen per mole of nitrogen, at 300°C and 30 MPa killed four people. Initial investigation had excluded potential external ignition sources and the main aim of the research was to determine the cause of ignition. Hydrogen is currently considered as a potential fuel for various vehicles such as cars, trucks, buses, etc. Crucial safety issues are of potential concern, associated with the storage of hydrogen at a very high pressure. Indeed, the evidence obtained nearly 40 years ago shows that sudden rupture of a high-pressure hydrogen storage tank or other component can result in ignition and potentially explosion. The aim of the present research is identification of the conditions under which hydrogen ignition occurs as a result of compression and heating of the air by the shock wave generated by discharge of high-pressure hydrogen. Experiments have been conducted using a facility constructed in the Combustion Laboratory of the Institute of Heat Engineering, Warsaw University of Technology. Tests under various configurations have been performed to determine critical conditions for occurrence of high-pressure hydrogen ignition. The results show that a critical pressure exists, leading to ignition, which depends mainly on the geometric configuration of the outflow system, such as tube diameter, and on the presence of obstacles.

  16. Boiling heat transfer and dryout in helically coiled tubes under different pressure conditions

    International Nuclear Information System (INIS)

    Chung, Young-Jong; Bae, Kyoo-Hwan; Kim, Keung Koo; Lee, Won-Jae

    2014-01-01

    Highlights: • Heat transfer characteristics and dryout for helically coiled tube are performed. • A boiling heat transfer tends to increase with a pressure increase. • Dryout occurs at high quality test conditions investigated. • Steiner–Taborek’s correlation is predicted well based on the experimental results. - Abstract: A helically coiled once-through steam generator has been used widely during the past several decades for small nuclear power reactors. The heat transfer characteristics and dryout conditions are important to optimal design a helically coiled steam generator. Various experiments with the helically coiled tubes are performed to investigate the heat transfer characteristics and occurrence condition of a dryout. For the investigated experimental conditions, Steiner–Taborek’s correlation is predicted reasonably based on the experimental results. The pressure effect is important for the boiling heat transfer correlation. A boiling heat transfer tends to increase with a pressure increase. However, it is not affected by the pressure change at a low power and low mass flow rate. Dryout occurs at high quality test conditions investigated because a liquid film on the wall exists owing to a centrifugal force of the helical coil

  17. Iron exclusion in rice genotypes as affected by different vapor pressure deficit conditions

    Directory of Open Access Journals (Sweden)

    Ram Kumar Shrestha

    2015-08-01

    Full Text Available Root iron (Fe exclusion capacity of four lowland rice genotypes were evaluated in increasing rate of Fe2+ stresses (0, 500, 1000 and 1500 mg/L in growing medium under the conditions of low and high vapor pressure deficit. Rice root excluded significantly higher amount of iron under dry atmospheric condition (655 mg Fe/g root dry matter than moist atmospheric condition (118 mg Fe/g root dry matter. But their iron exclusion capacity reduced when they were gradually exposed to the higher levels of Fe stress. Tolerant genotype such as TOX3107 excluded more iron when they were exposed to dry atmospheric condition.

  18. Superconductivity from magnetic elements under high pressure

    International Nuclear Information System (INIS)

    Shimizu, Katsuya; Amaya, Kiichi; Suzuki, Naoshi; Onuki, Yoshichika

    2006-01-01

    Can we expect the appearance of superconductivity from magnetic elements? In general, superconductivity occurs in nonmagnetic metal at low temperature and magnetic impurities destroy superconductivity; magnetism and superconductivity are as incompatible as oil and water. Here, we present our experimental example of superconducting elements, iron and oxygen. They are magnetic at ambient pressure, however, they become nonmagnetic under high pressure, then superconductor at low temperature. What is the driving force of the superconductivity? Our understanding in the early stages was a simple scenario that the superconductive state was obtained as a consequence of an emergence of the nonmagnetic states. In both cases, we may consider another scenario for the appearance of superconductivity; the magnetic fluctuation mechanism in the same way as unconventional superconductors

  19. Sizing of high-pressure restriction orifices

    International Nuclear Information System (INIS)

    Casado Flores, E.

    1995-01-01

    Constant up-grading of power plants sometimes requires the modification of components which form part of suppliers' packages. In order to protect technology they have developed, however, the suppliers do not supply their calculation criteria. In order to reduce the costs of such improvements, and so as to be able to undertake the modification without having to rely on the original supplier, this paper describes the basic criteria applicable to the study of high-pressure restriction orifices, which can be considered to be representative of the components in question. The restriction orifices discussed are: - Insert - Multiplates in series with one perforation in each plate - Multiplates in series with several perforations in each plate For each type, an explanation of their sizing is given, together with the equations relating the corresponding flow and pressure drop. (Author)

  20. 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...

  1. SrWO4 at high pressures

    International Nuclear Information System (INIS)

    Grzechnik, A.; Crichton, W.A.; Hanfland, M.

    2005-01-01

    Room-temperature high-pressure behaviour of SrWO 4 scheelite (I4 1 /a, Z=4) has been studied to 20.7 GPa in a diamond anvil cell using synchrotron angle-dispersive X-ray powder diffraction. Above 10 GPa, it transforms to the fergusonite structure (I2/a, Z=4). Both scheelite and fergusonite types are ordered superstructures of fluorite (Fm anti 3m, Z=4). There is no significant volume collapse at the scheelite-fergusonite phase transition. However, the compression data including both phases of strontium tungstate cannot be fitted by a common Birch-Murnaghan equation of state. An onset of decomposition into component oxides occurs at about 15 GPa. The pressure-induced transformations are irreversible. (copyright 2005 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  2. High-pressure phase transitions of deep earth materials

    International Nuclear Information System (INIS)

    Hirose, Kei

    2009-01-01

    Recent developments in synchrotron XRD measurements combined with laser-heated diamond-anvil cell (LHDAC) techniques have enabled us to search for a novel phase transition at extremely high pressure and temperature. A phase transition from MgSiO 3 perovskite to post-perovskite was discovered through a drastic change in XRD patterns above 120 GPa and 2500 K, corresponding to the condition in the lowermost mantle (Murakami et al., 2004; Oganov and Ono, 2004). A pressure-induced phase transformation from ABO 3 -type perovskite to any denser structures was not known at that time. This new MgSiO 3 polymorph called post-perovskite has an orthorhombic symmetry (space group: Cmcm) with a sheet-stacking structure. The Mg site in post-perovskite is smaller than that in perovskite, which results in a volume reduction by 1.0-1.5% from perovskite structure. The electrical conductivity of post-perovskite is higher by three orders of magnitude than that of perovskite at similar pressure range (Ohta et al., 2008). This is likely due to a shorter Fe-Fe distance in post-perovskite structure, while conduction mechanism is yet to be further examined. Phase transition boundary between perovskite and post-perovskite has been determined in a wide temperature range up to 4400 K at 170 GPa (Tateno et al., 2008). Phase relations of Fe alloys have been also studied at core pressures (>135 GPa), although the generation of high temperature is more difficult at higher pressures. A new high-pressure B2 phase of B2 phase of FeS was recently discovered above 180 GPa (Sata et al., 2008). The Fe-Ni alloys have a wide pressure-temperature stability field of fcc phase at the core pressure range, depending on the Ni content (Kuwayama et al., 2008). (author)

  3. Determination of optimal conditions for pressure oxidative leaching of Sarcheshmeh Molybdenite concentrate using Taguchi method

    Directory of Open Access Journals (Sweden)

    Khoshnevisana A.

    2012-01-01

    Full Text Available The present research work is based on finding the optimum conditions for pressure oxidative leaching of the molybdenite concentrate to produce technical-grade molybdic oxide (MoO3 with high recovery through further treatment of the filtrate solution. The Taguchi method was used to design and minimize the number of experiments. By using Taguchi orthogonal (L25 array, five parameters (time, temperature, oxygen pressure, pulp density and acid concentration at five levels were selected for 25 experiments. The experiments were designed and carried out in a high-pressure reactor in the presence of nitric acid as solvent and oxidizing agent for the molybdenite concentrate and its ReS2 content. The optimum conditions for pressure leaching of molybdenite were obtained through using Signal to Noise analysis and modified by using Minitab software prediction tool. Furthermore, the optimum condition for an economical pressure leaching of rhenium sulfide (ReS2 was achieved with the same process. Analysis of variance (ANOVA showed that the pulp density is of paramount importance in this process.

  4. 30 CFR 57.13021 - High-pressure hose connections.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false High-pressure hose connections. 57.13021... Air and Boilers § 57.13021 High-pressure hose connections. Except where automatic shutoff valves are...-pressure hose lines of 3/4-inch inside diameter or larger, and between high-pressure hose lines of 3/4-inch...

  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. 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

  7. 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.

  8. 49 CFR 192.621 - Maximum allowable operating pressure: High-pressure distribution systems.

    Science.gov (United States)

    2010-10-01

    ... STANDARDS Operations § 192.621 Maximum allowable operating pressure: High-pressure distribution systems. (a) No person may operate a segment of a high pressure distribution system at a pressure that exceeds the... segment of a distribution system otherwise designed to operate at over 60 p.s.i. (414 kPa) gage, unless...

  9. Recent progress in high-pressure studies on organic conductors

    Directory of Open Access Journals (Sweden)

    Syuma Yasuzuka and Keizo Murata

    2009-01-01

    Full Text Available Recent high-pressure studies of organic conductors and superconductors are reviewed. The discovery of the highest Tc superconductivity among organics under high pressure has triggered the further progress of the high-pressure research. Owing to this finding, various organic conductors with the strong electron correlation were investigated under high pressures. This review includes the pressure techniques using the cubic anvil apparatus, as well as high-pressure studies of the organic conductors up to 10 GPa showing extraordinary temperature and pressure dependent transport phenomena.

  10. Condensed matter at high shock pressures

    International Nuclear Information System (INIS)

    Nellis, W.J.; Holmes, N.C.; Mitchell, A.C.; Radousky, H.B.; Hamilton, D.

    1985-01-01

    Experimental techniques are described for shock waves in liquids: Hugoniot equation-of-state, shock temperature and emission spectroscopy, electrical conductivity, and Raman spectroscopy. Experimental data are reviewed and presented in terms of phenomena that occur at high densities and temperatures in shocked He, Ar, N 2 , CO, SiO 2 -aerogel, H 2 O, and C 6 H 6 . The superconducting properties of Nb metal shocked to 100 GPa (1 Mbar) and recovered intact are discussed in terms of prospects for synthesizing novel, metastable materials. Ultrahigh pressure data for Cu is reviewed in the range 0.3 to 6TPa (3 to 60 Mbar). 56 refs., 9 figs., 1 tab

  11. Commentary on differential-pressure measurements at high reference pressures

    International Nuclear Information System (INIS)

    Hasbrouck, R.T.; Noyes, R.P.

    1981-01-01

    Some practical approaches to the difficult problems in calibrating and implementing differential-pressure measurements are discussed. The data presented were gathered several years ago in separate investigations. An attempt is made to compare the results of these investigations to the common mode concept as described by Peter K. Stein in his publication, The Measurement of Differential Quantities - Problems and Approaches. Although one of these investigations involed a 10,000- to 20,000-psi reference-pressure gas measured at an ambient temperature and the other a classic /sup Δ/P flow measurement of cryogenic temperature, the problems encountered were the same

  12. Conformable pressure vessel for high pressure gas storage

    Science.gov (United States)

    Simmons, Kevin L.; Johnson, Kenneth I.; Lavender, Curt A.; Newhouse, Norman L.; Yeggy, Brian C.

    2016-01-12

    A non-cylindrical pressure vessel storage tank is disclosed. The storage tank includes an internal structure. The internal structure is coupled to at least one wall of the storage tank. The internal structure shapes and internally supports the storage tank. The pressure vessel storage tank has a conformability of about 0.8 to about 1.0. The internal structure can be, but is not limited to, a Schwarz-P structure, an egg-crate shaped structure, or carbon fiber ligament structure.

  13. 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.

  14. Thermal versus high pressure processing of carrots: A comparative pilot-scale study on equivalent basis

    NARCIS (Netherlands)

    Vervoort, L.; Plancken, Van der L.; Grauwet, T.; Verlinde, P.; Matser, A.M.; Hendrickx, M.; Loey, van A.

    2012-01-01

    This report describes the first study comparing different high pressure (HP) and thermal treatments at intensities ranging from mild pasteurization to sterilization conditions. To allow a fair comparison, the processing conditions were selected based on the principles of equivalence. Moreover,

  15. Study on vortex cavitation in a compact fast reactor. Effects of system pressure on inception condition

    International Nuclear Information System (INIS)

    Hiroyuki Sato; Toshiki Ezure; Hideki Kamide

    2005-01-01

    A compact sodium reactor is designed as a commercialized fast reactor cycle system. A 1/10 scaled water experiment was performed to optimize flow in an upper plenum of the reactor vessel, because of high flow velocity resulted from the compacted vessel. In the experiment, vortex cavitation was found at the hot leg inlet because of high velocity in the hot leg pipe (9.4m/s in the design). To evaluate cavitation inception condition of the commercialized reactor, we use the cavitation number k in order to consider the difference of system pressures (0.1MPa in the experiment and 0.3MPa in the design). The minimum pressure at the vortex center will depend on vortex core radius (size of forced vortex region). It is related to axial velocity gradient and fluid viscosity in theory of the Burger's stretched vortex model. We carried out a basic water experiment to investigate the influence of system pressure and fluid viscosity on the vortex cavitation. The cavitation number at the inception of vortex cavitation slightly increased according to the increase of the system pressure. It means that the vortex cavitation occurs easily under higher pressure condition as compared with the similar condition of cavitation number with lower pressure. However the increase was less than 30% when the system pressure was varied from 0.1 to 0.3MPa. The influence of fluid viscosity was examined by change of fluid temperature. Velocity distribution around the vortex was also measured to see the structure of vortex. (authors)

  16. Computational Fluid Dynamics Analysis of High Injection Pressure Blended Biodiesel

    Science.gov (United States)

    Khalid, Amir; Jaat, Norrizam; Faisal Hushim, Mohd; Manshoor, Bukhari; Zaman, Izzuddin; Sapit, Azwan; Razali, Azahari

    2017-08-01

    Biodiesel have great potential for substitution with petrol fuel for the purpose of achieving clean energy production and emission reduction. Among the methods that can control the combustion properties, controlling of the fuel injection conditions is one of the successful methods. The purpose of this study is to investigate the effect of high injection pressure of biodiesel blends on spray characteristics using Computational Fluid Dynamics (CFD). Injection pressure was observed at 220 MPa, 250 MPa and 280 MPa. The ambient temperature was kept held at 1050 K and ambient pressure 8 MPa in order to simulate the effect of boost pressure or turbo charger during combustion process. Computational Fluid Dynamics were used to investigate the spray characteristics of biodiesel blends such as spray penetration length, spray angle and mixture formation of fuel-air mixing. The results shows that increases of injection pressure, wider spray angle is produced by biodiesel blends and diesel fuel. The injection pressure strongly affects the mixture formation, characteristics of fuel spray, longer spray penetration length thus promotes the fuel and air mixing.

  17. High blood pressure and visual sensitivity

    Science.gov (United States)

    Eisner, Alvin; Samples, John R.

    2003-09-01

    The study had two main purposes: (1) to determine whether the foveal visual sensitivities of people treated for high blood pressure (vascular hypertension) differ from the sensitivities of people who have not been diagnosed with high blood pressure and (2) to understand how visual adaptation is related to standard measures of systemic cardiovascular function. Two groups of middle-aged subjects-hypertensive and normotensive-were examined with a series of test/background stimulus combinations. All subjects met rigorous inclusion criteria for excellent ocular health. Although the visual sensitivities of the two subject groups overlapped extensively, the age-related rate of sensitivity loss was, for some measures, greater for the hypertensive subjects, possibly because of adaptation differences between the two groups. Overall, the degree of steady-state sensitivity loss resulting from an increase of background illuminance (for 580-nm backgrounds) was slightly less for the hypertensive subjects. Among normotensive subjects, the ability of a bright (3.8-log-td), long-wavelength (640-nm) adapting background to selectively suppress the flicker response of long-wavelength-sensitive (LWS) cones was related inversely to the ratio of mean arterial blood pressure to heart rate. The degree of selective suppression was also related to heart rate alone, and there was evidence that short-term changes of cardiovascular response were important. The results suggest that (1) vascular hypertension, or possibly its treatment, subtly affects visual function even in the absence of eye disease and (2) changes in blood flow affect retinal light-adaptation processes involved in the selective suppression of the flicker response from LWS cones caused by bright, long-wavelength backgrounds.

  18. From simple to complex and backwards. Chemical reactions under very high pressure

    International Nuclear Information System (INIS)

    Bini, Roberto; Ceppatelli, Matteo; Citroni, Margherita; Schettino, Vincenzo

    2012-01-01

    Highlights: ► High pressure reactivity of several molecular systems. ► Reaction kinetics and dynamics in high density conditions. ► Key role of optical pumping and electronic excitation. ► Perspectives for the synthesis of hydrogen. - Abstract: High pressure chemical reactions of molecular systems are discussed considering the various factors that can affect the reactivity. These include steric hindrance and geometrical constraints in the confined environment of crystals at high pressure, changes of the free energy landscape with pressure, photoactivation by two-photon absorption, local and collective effects. A classification of the chemical reactions at high pressure is attempted on the basis of the prevailing factors.

  19. Frictional pressure drop of high pressure steam-water two-phase flow in internally helical ribbed tubes

    International Nuclear Information System (INIS)

    Tingkuan, C.; Xuanzheng, C.

    1987-01-01

    It is well known that the internally helical ribbed tubes are effective in suppressing the dry-out in boiling tubes at high pressures, so they are widely used as furnace water wall tubes in modern large steam power boilers. Design of the boilers requires the data on frictional pressure drop characteristics of the ribbed tubes, but they are not sufficient now. This paper describes the experimental results on the adiabatic frictional pressure drop in both horizontal ribbed tubes with measured mean inside diameter of 11.69 mm and 35.42 mm at high pressure from 10 to 21 MPa, mass flow rate from 350 to 3800 kg/m/sup 2/s and steam quality from 0 to 1 in our high pressure electrically heated water loop. Simultaneously, both smooth tubes under the same conditions for comparison. Based on the tests the correlation for determining the frictional pressure drop of internally ribbed tubes are proposed

  20. Prediction of pressure between packers of staged fracturing pipe strings in high-pressure deep wells and its application

    Directory of Open Access Journals (Sweden)

    Fuxiang Zhang

    2015-03-01

    Full Text Available Addressing to the deteriorated load conditions of working string and packers caused by annular pressure drop between packers during the staged stimulation of high-pressure deep well, one 2D temperature field transient prediction model for borehole under injecting conditions which considers such influences as friction heat, convection heat exchange was set up, based on energy conservation principle and borehole heat transfer theory. By means of analyzing the influences of borehole temperature and pressure changes on the annular volume between packers, and in combination with borehole temperature transient prediction model, annular fluid PVT equations of state, radial deformation model of tubing and formation transient seepage equation, a typical high-pressure deep well inter-packer annular pressure prediction model was established. Taking a high-pressure gas well in Tarim Oilfield for example, the inter-packer annular pressure prediction was conducted, on which, the mechanical analysis on packers and working strings was carried out. The analysis results show that although the pipe string is safe in the viewpoint of conventional design methods, it is still susceptible to failure after the annular pressure drop between packers was taken into consideration. Such factor should be fully considered in the design of staged stimulation pipe strings, and this prediction model provides new thoughts for the optimal design of high-pressure deep well staged stimulation pipe strings.

  1. Loads on EPR containment after RPV failure at high pressure

    International Nuclear Information System (INIS)

    Jacobs, G.

    1995-01-01

    As regards the desgin of the EPR, the general strategy is to eliminate, the vessel failure at high pressure by preventive and mitigative measures. The design proposals involved trust in the reliability of dedicated devices (relief valves) for rapid depressurization. The aim is to attain a lower pressure level at the moment of vessel failure, so that the containment is capable to cope with the blowdown impact on the pit walls and the vessel supporting structures. Nevertheless, the potential of a high-pressure failure of the vessel must be kept in mind, whatever well thought-out and reliable preventive depressurization measures might be. Therefore, the reactor pressure blowdown has been studied in order to quantify the ultimate containment load, which might support future design requirements. The calculations were performed with the LWR transient analysis thermal-hydraulics computer code REALAP5/MOD3. In previous analyses, the nodalization of the problem was based on the geometrical conditions of a typical German 1300 MW(e) NPP. In the present analysis a new input model has been used, which was based on the EPR conditions. (orig./HP)

  2. Food processing by high hydrostatic pressure.

    Science.gov (United States)

    Yamamoto, Kazutaka

    2017-04-01

    High hydrostatic pressure (HHP) process, as a nonthermal process, can be used to inactivate microbes while minimizing chemical reactions in food. In this regard, a HHP level of 100 MPa (986.9 atm/1019.7 kgf/cm 2 ) and more is applied to food. Conventional thermal process damages food components relating color, flavor, and nutrition via enhanced chemical reactions. However, HHP process minimizes the damages and inactivates microbes toward processing high quality safe foods. The first commercial HHP-processed foods were launched in 1990 as fruit products such as jams, and then some other products have been commercialized: retort rice products (enhanced water impregnation), cooked hams and sausages (shelf life extension), soy sauce with minimized salt (short-time fermentation owing to enhanced enzymatic reactions), and beverages (shelf life extension). The characteristics of HHP food processing are reviewed from viewpoints of nonthermal process, history, research and development, physical and biochemical changes, and processing equipment.

  3. Industrial high pressure applications. Processes, equipment and safety

    Energy Technology Data Exchange (ETDEWEB)

    Eggers, Rudolf (ed.) [Technische Univ. Hamburg-Harburg, Hamburg (Germany). Inst. fuer Thermische Verfahrenstechnik

    2012-07-01

    Industrial high pressure processes open the door to many reactions that are not possible under 'normal' conditions. These are to be found in such different areas as polymerization, catalytic reactions, separations, oil and gas recovery, food processing, biocatalysis and more. The most famous high pressure process is the so-called Haber-Bosch process used for fertilizers and which was awarded a Nobel prize. Following an introduction on historical development, the current state, and future trends, this timely and comprehensive publication goes on to describe different industrial processes, including methanol and other catalytic syntheses, polymerization and renewable energy processes, before covering safety and equipment issues. With its excellent choice of industrial contributions, this handbook offers high quality information not found elsewhere, making it invaluable reading for a broad and interdisciplinary audience.

  4. Prevalence of sedentary lifestyle in individuals with high blood pressure.

    Science.gov (United States)

    Guedes, Nirla Gomes; Lopes, Marcos Venícios de Oliveira; Moreira, Rafaella Pessoa; Cavalcante, Tahissa Frota; de Araujo, Thelma Leite

    2010-01-01

    To identify the prevalence of a sedentary lifestyle in individuals with high blood pressure. This cross-sectional study was conducted among 310 individuals with high blood pressure. The prevalence of the diagnosis of sedentary lifestyle was 60%. The more common defining characteristics were "lack of physical conditioning" and "lack of practice for physical exercises." The nursing diagnosis was associated with age and presence of diabetes. Individuals who presented with a sedentary lifestyle related to lack of motivation were significantly younger. This study showed a high prevalence of "sedentary lifestyle" and its associations with age and the presence of diabetes. IMPLICATIONS TO NURSING PRACTICE: The acknowledgement of "sedentary lifestyle" contributes to the choice for nursing interventions that promote physical activity centered on the subject and the surroundings.

  5. New technology for carbon dioxide at high pressure

    International Nuclear Information System (INIS)

    Hassina, Bazaze; Raouf, Zehioua; Menial, A. H.

    2006-01-01

    Carbon dioxide has long been the nemesis of environmentalists because of its role in global warming, but under just the right conditions-namely, high pressure and high temperature its one of nature's best and most environmentally benign solvents. Decaf-coffee lovers, for instance, benefit from its ability to remove caffeine from coffee beans.During the last few years, carbon dioxide has also made inroads in the dry-cleaning industry, providing a safe cleaning alternative to the chemical perchloroethylene. But it's on the high-tech front that carbon dioxide may make its biggest impact. T here are huge opportunities. Scientists have known for more than a century that at 75 times atmospheric pressure and 31 degree centigrade, carbon dioxide goes into and odd state that chemists called s upercritical . What's interesting to industry is that supercritical carbon dioxide may be an enabling technology for going to smaller dimensions.(Author)

  6. Effect of Low Pressure End Conditions on Steam Power Plant Performance

    Directory of Open Access Journals (Sweden)

    Ali Syed Haider

    2014-07-01

    Full Text Available Most of the electricity produced throughout the world today is from steam power plants and improving the performance of power plants is crucial to minimize the greenhouse gas emissions and fuel consumption. Energy efficiency of a thermal power plant strongly depends on its boiler-condenser operating conditions. The low pressure end conditions of a condenser have influence on the power output, steam consumption and efficiency of a plant. Hence, the objective this paper is to study the effect of the low pressure end conditions on a steam power plant performance. For the study each component was modelled thermodynamically. Simulation was done and the results showed that performance of the condenser is highly a function of its pressure which in turn depends on the flow rate and temperature of the cooling water. Furthermore, when the condenser pressure increases both net power output and plant efficiency decrease whereas the steam consumption increases. The results can be used to run a steam power cycle at optimum conditions.

  7. Response of a DSNP pressurizer model under accident conditions

    International Nuclear Information System (INIS)

    Saphier, D.; Kallfelz, J.; Belblidia, L.

    1986-01-01

    Recently a new pressurizer model was developed for the DSNP simulation language. The model was connected to a simulation of the Trojan pressurized water reactor (PWR) and tested by simulating a loss-of-off-site power (LOSP) anticipated transient without scram. The results compare well to a similar study performed using the RELAP code. The pressurizer model and its response to the LOSP accident are presented

  8. Effect of processing conditions on oil point pressure of moringa oleifera seed.

    Science.gov (United States)

    Aviara, N A; Musa, W B; Owolarafe, O K; Ogunsina, B S; Oluwole, F A

    2015-07-01

    Seed oil expression is an important economic venture in rural Nigeria. The traditional techniques of carrying out the operation is not only energy sapping and time consuming but also wasteful. In order to reduce the tedium involved in the expression of oil from moringa oleifera seed and develop efficient equipment for carrying out the operation, the oil point pressure of the seed was determined under different processing conditions using a laboratory press. The processing conditions employed were moisture content (4.78, 6.00, 8.00 and 10.00 % wet basis), heating temperature (50, 70, 85 and 100 °C) and heating time (15, 20, 25 and 30 min). Results showed that the oil point pressure increased with increase in seed moisture content, but decreased with increase in heating temperature and heating time within the above ranges. Highest oil point pressure value of 1.1239 MPa was obtained at the processing conditions of 10.00 % moisture content, 50 °C heating temperature and 15 min heating time. The lowest oil point pressure obtained was 0.3164 MPa and it occurred at the moisture content of 4.78 %, heating temperature of 100 °C and heating time of 30 min. Analysis of Variance (ANOVA) showed that all the processing variables and their interactions had significant effect on the oil point pressure of moringa oleifera seed at 1 % level of significance. This was further demonstrated using Response Surface Methodology (RSM). Tukey's test and Duncan's Multiple Range Analysis successfully separated the means and a multiple regression equation was used to express the relationship existing between the oil point pressure of moringa oleifera seed and its moisture content, processing temperature, heating time and their interactions. The model yielded coefficients that enabled the oil point pressure of the seed to be predicted with very high coefficient of determination.

  9. Engineering Model of High Pressure Moist Air

    Directory of Open Access Journals (Sweden)

    Hyhlík Tomáš

    2017-01-01

    Full Text Available The article deals with the moist air equation of state. There are equations of state discussed in the article, i.e. the model of an ideal mixture of ideal gases, the model of an ideal mixture of real gases and the model based on the virial equation of state. The evaluation of sound speed based on the ideal mixture concept is mentioned. The sound speed calculated by the model of an ideal mixture of ideal gases is compared with the sound speed calculated by using the model based on the concept of an ideal mixture of real gases. The comparison of enthalpy end entropy based on the model of an ideal mixture of ideal gases and the model of an ideal mixture of real gases is performed. It is shown that the model of an ideal mixture of real gases deviates from the model of an ideal mixture of ideal gases only in the case of high pressure. An impossibility of the definition of partial pressure in the mixture of real gases is discussed, where the virial equation of state is used.

  10. [High blood pressure and physical exercise].

    Science.gov (United States)

    Sosner, P; Gremeaux, V; Bosquet, L; Herpin, D

    2014-06-01

    High blood pressure is a frequent pathology with many cardiovascular complications. As highlighted in guidelines, the therapeutic management of hypertension relies on non-pharmacological measures, which are diet and regular physical activity, but both patients and physicians are reluctant to physical activity prescription. To acquire the conviction that physical activity is beneficial, necessary and possible, we can take into account some fundamental and clinical studies, as well as the feedback of our clinical practice. Physical inactivity is a major risk factor for cardiovascular morbidity and mortality, and hypertension contributes to increase this risk. Conversely, regular practice of physical activity decreases very significantly the risk by up to 60%. The acute blood pressure changes during exercise and post-exercise hypotension differs according to the dynamic component (endurance or aerobic and/or strength exercises), but the repetition of the sessions leads to the chronic hypotensive benefit of physical activity. Moreover, physical activity prescription must take into account the assessment of global cardiovascular risk, the control of the hypertension, and the opportunities and desires of the patient in order to promote good adherence and beneficial lifestyle change. Copyright © 2014 Elsevier Masson SAS. All rights reserved.

  11. High Pressure Reduction of Selenite by Shewanella oneidensis MR-1

    Science.gov (United States)

    Picard, A.; Daniel, I.; Testemale, D.; Letard, I.; Bleuet, P.; Cardon, H.; Oger, P.

    2007-12-01

    High-pressure biotopes comprise cold deep-sea environments, hydrothermal vents, and deep subsurface or deep-sea sediments. The latter are less studied, due to the technical difficulties to sample at great depths without contamination. Nevertheless, microbial sulfate reduction and methanogenesis have been found to be spatially distributed in deep deep-sea sediments (1), and sulfate reduction has been shown to be actually more efficient under high hydrostatic pressure (HHP) in some sediments (2). Sulfate-reducing bacteria obtained from the Japan Sea are characterized by an increased sulfide production under pressure (3,4). Unfortunately, investigations of microbial metabolic activity as a function of pressure are extremely scarce due to the experimental difficulty of such measurements at high hydrostatic pressure. We were able to measure the reduction of selenite Se(IV) by Shewanella oneidensis MR-1 as a function of pressure, to 150 MPa using two different high-pressure reactors that allow in situ X-ray spectroscopy measurements on a synchrotron source. A first series of measurements was carried out in a low-pressure Diamond Anvil Cell (DAC) of our own design (5) at ID22 beamline at ESRF (European Synchrotron Radiation Facility); a second one was performed in an autoclave (6) at the BM30B beamline at ESRF. Selenite reduction by strain MR-17 was monitored from ambient pressure to 150 MPa over 25 hours at 30 deg C by XANES spectroscopy (X-ray Analysis of Near Edge Structure). Spectra were recorded hourly in order to quantify the evolution of the oxidation state of selenium with time. Stationary-phase bacteria were inoculated at a high concentration into fresh growth medium containing 5 or 10 M of sodium selenite and 20 mM sodium lactate. Kinetic parameters of the Se (IV) reduction by Shewanella oneidensis strain MR-1 could be extracted from the data, as a function of pressure. They show 1) that the rate constant k of the reaction is decreased by a half at high pressure

  12. 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...

  13. 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)

  14. High pressure fiber optic sensor system

    Science.gov (United States)

    Guida, Renato; Xia, Hua; Lee, Boon K; Dekate, Sachin N

    2013-11-26

    The present application provides a fiber optic sensor system. The fiber optic sensor system may include a small diameter bellows, a large diameter bellows, and a fiber optic pressure sensor attached to the small diameter bellows. Contraction of the large diameter bellows under an applied pressure may cause the small diameter bellows to expand such that the fiber optic pressure sensor may measure the applied pressure.

  15. Touch mode micromachined capacitive pressure sensor with signal conditioning electronics

    DEFF Research Database (Denmark)

    Fragiacomo, Giulio; Eriksen, Gert F.; Christensen, Carsten

    2010-01-01

    In the last decades, pressure sensors have been one of the greatest successes of the MEMS industry. Many companies are using them in a variety of applications from the automotive to the environmental field. Currently piezoresistive pressure sensors are the most developed, and a well established t...

  16. High Pressure Hydrogen Pressure Relief Devices: Accelerated Life Testing and Application Best Practices

    Energy Technology Data Exchange (ETDEWEB)

    Burgess, Robert M. [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Post, Matthew B. [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Buttner, William J. [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Rivkin, Carl H. [National Renewable Energy Laboratory (NREL), Golden, CO (United States)

    2017-11-06

    Pressure relief devices (PRDs ) are used to protect high pressure systems from burst failure caused by overpressurization. Codes and standards require the use of PRDs for the safe design of many pressurized systems. These systems require high reliability due to the risks associated with a burst failure. Hydrogen service can increase the risk of PRD failure due to material property degradation caused by hydrogen attack. The National Renewable Energy Laboratory (NREL) has conducted an accelerated life test on a conventional spring loaded PRD. Based on previous failures in the field, the nozzles specific to these PRDs are of particular interest. A nozzle in a PRD is a small part that directs the flow of fluid toward the sealing surface to maintain the open state of the valve once the spring force is overcome. The nozzle in this specific PRD is subjected to the full tensile force of the fluid pressure. These nozzles are made from 440C material, which is a type of hardened steel that is commonly chosen for high pressure applications because of its high strength properties. In a hydrogen environment, however, 440C is considered a worst case material since hydrogen attack results in a loss of almost all ductility and thus 440C is prone to fatigue and material failure. Accordingly, 440C is not recommended for hydrogen service. Conducting an accelerated life test on a PRD with 440C material provides information on necessary and sufficient conditions required to produce crack initiation and failure. The accelerated life test also provides information on other PRD failure modes that are somewhat statistically random in nature.

  17. Computer simulations of high pressure systems

    International Nuclear Information System (INIS)

    Wilkins, M.L.

    1977-01-01

    Numerical methods are capable of solving very difficult problems in solid mechanics and gas dynamics. In the design of engineering structures, critical decisions are possible if the behavior of materials is correctly described in the calculation. Problems of current interest require accurate analysis of stress-strain fields that range from very small elastic displacement to very large plastic deformation. A finite difference program is described that solves problems over this range and in two and three space-dimensions and time. A series of experiments and calculations serve to establish confidence in the plasticity formulation. The program can be used to design high pressure systems where plastic flow occurs. The purpose is to identify material properties, strength and elongation, that meet the operating requirements. An objective is to be able to perform destructive testing on a computer rather than on the engineering structure. Examples of topical interest are given

  18. Urea and deuterium mixtures at high pressures

    Energy Technology Data Exchange (ETDEWEB)

    Donnelly, M., E-mail: m.donnelly-2@sms.ed.ac.uk; Husband, R. J.; Frantzana, A. D.; Loveday, J. S. [Centre for Science at Extreme Conditions and School of Physics and Astronomy, The University of Edinburgh, Erskine Williamson Building, Peter Guthrie Tait Road, The King’s Buildings, Edinburgh EH9 3FD (United Kingdom); Bull, C. L. [ISIS, Rutherford Appleton Laboratory, Oxford Harwell, Didcot OX11 0QX (United Kingdom); Klotz, S. [IMPMC, CNRS UMR 7590, Université P and M Curie, 4 Place Jussieu, 75252 Paris (France)

    2015-03-28

    Urea, like many network forming compounds, has long been known to form inclusion (guest-host) compounds. Unlike other network formers like water, urea is not known to form such inclusion compounds with simple molecules like hydrogen. Such compounds if they existed would be of interest both for the fundamental insight they provide into molecular bonding and as potential gas storage systems. Urea has been proposed as a potential hydrogen storage material [T. A. Strobel et al., Chem. Phys. Lett. 478, 97 (2009)]. Here, we report the results of high-pressure neutron diffraction studies of urea and D{sub 2} mixtures that indicate no inclusion compound forms up to 3.7 GPa.

  19. Recent developments in high pressure water technology

    International Nuclear Information System (INIS)

    Johnson, N.A.; Johnson, T.

    1992-01-01

    High Pressure Water Jetting has advanced rapidly in the last decade to a point where the field is splitting into specialised areas. This has left the end user or client in the dark as to whether water jetting will work and if so what equipment is best suited to their particular application. The aim of this paper is to give an overview of:-1. The way water is delivered to the surface and the parameters which control the concentration of energy available on impact. 2. The factors governing application driven selection of equipment. 3. The effects to technical advances in pumps and delivery systems on equipment selection with reference to their to their application to concrete removal and nuclear decontamination. (Author)

  20. Condensed matter at high shock pressures

    Energy Technology Data Exchange (ETDEWEB)

    Nellis, W.J.; Holmes, N.C.; Mitchell, A.C.; Radousky, H.B.; Hamilton, D.

    1985-07-12

    Experimental techniques are described for shock waves in liquids: Hugoniot equation-of-state, shock temperature and emission spectroscopy, electrical conductivity, and Raman spectroscopy. Experimental data are reviewed and presented in terms of phenomena that occur at high densities and temperatures in shocked He, Ar, N/sub 2/, CO, SiO/sub 2/-aerogel, H/sub 2/O, and C/sub 6/H/sub 6/. The superconducting properties of Nb metal shocked to 100 GPa (1 Mbar) and recovered intact are discussed in terms of prospects for synthesizing novel, metastable materials. Ultrahigh pressure data for Cu is reviewed in the range 0.3 to 6TPa (3 to 60 Mbar). 56 refs., 9 figs., 1 tab.

  1. High-pressure structures of methane hydrate

    International Nuclear Information System (INIS)

    Hirai, H; Uchihara, Y; Fujihisa, H; Sakashita, M; Katoh, E; Aoki, K; Yamamoto, Y; Nagashima, K; Yagi, T

    2002-01-01

    Three high-pressure structures of methane hydrate, a hexagonal structure (str. A) and two orthorhombic structures (str. B and str. C), were found by in situ x-ray diffractometry and Raman spectroscopy. The well-known structure I (str. I) decomposed into str. A and fluid at 0.8 GPa. Str. A transformed into str. B at 1.6 GPa, and str. B further transformed into str. C at 2.1 GPa which survived above 7.8 GPa. The fluid solidified as ice VI at 1.4 GPa, and the ice VI transformed to ice VII at 2.1 GPa. The bulk moduli, K 0 , for str. I, str. A, and str. C were calculated to be 7.4, 9.8, and 25.0 GPa, respectively

  2. High Pressure Quick Disconnect Particle Impact Tests

    Science.gov (United States)

    Rosales, Keisa R.; Stoltzfus, Joel M.

    2009-01-01

    NASA Johnson Space Center White Sands Test Facility (WSTF) performed particle impact testing to determine whether there is a particle impact ignition hazard in the quick disconnects (QDs) in the Environmental Control and Life Support System (ECLSS) on the International Space Station (ISS). Testing included standard supersonic and subsonic particle impact tests on 15-5 PH stainless steel, as well as tests performed on a QD simulator. This paper summarizes the particle impact tests completed at WSTF. Although there was an ignition in Test Series 4, it was determined the ignition was caused by the presence of a machining imperfection. The sum of all the test results indicates that there is no particle impact ignition hazard in the ISS ECLSS QDs. KEYWORDS: quick disconnect, high pressure, particle impact testing, stainless steel

  3. Pressurizer and steam-generator behavior under PWR transient conditions

    International Nuclear Information System (INIS)

    Wahba, A.B.; Berta, V.T.; Pointner, W.

    1983-01-01

    Experiments have been conducted in the Loss-of-Fluid Test (LOFT) pressurized water reactor (PWR), at the Idaho National Engineering Laboratory, in which transient phenomena arising from accident events with and without reactor scram were studied. The main purpose of the LOFT facility is to provide data for the development of computer codes for PWR transient analyses. Significant thermal-hydraulic differences have been observed between the measured and calculated results for those transients in which the pressurizer and steam generator strongly influence the dominant transient phenomena. Pressurizer and steam generator phenomena that occurred during four specific PWR transients in the LOFT facility are discussed. Two transients were accompanied by pressurizer inflow and a reduction of the heat transfer in the steam generator to a very small value. The other two transients were accompanied by pressurizer outflow while the steam generator behavior was controlled

  4. Phase stability limit of c-BN under hydrostatic and non-hydrostatic pressure conditions

    International Nuclear Information System (INIS)

    Xiao, Jianwei; Du, Jinglian; Wen, Bin; Zhang, Xiangyi; Melnik, Roderick; Kawazoe, Yoshiyuki

    2014-01-01

    Phase stability limit of cubic boron nitride (c-BN) has been investigated by the crystal structure search technique. It indicated that this limit is ∼1000 GPa at hydrostatic pressure condition. Above this pressure, c-BN turns into a metastable phase with respect to rocksalt type boron nitride (rs-BN). However, rs-BN cannot be retained at 0 GPa owing to its instability at pressure below 250 GPa. For non-hydrostatic pressure conditions, the phase stability limit of c-BN is substantially lower than that under hydrostatic pressure conditions and it is also dramatically different for other pressure mode

  5. A Nutritional Strategy for the Treatment of High Blood Pressure.

    Science.gov (United States)

    Podell, Richard N.

    1984-01-01

    Some physicians wonder if high blood pressure can be controlled without the use of drugs and their potential side effects. Current findings concerning nutrition and high blood pressure are presented. (RM)

  6. Stress and High Blood Pressure: What's the Connection?

    Science.gov (United States)

    Stress and high blood pressure: What's the connection? Stress and long-term high blood pressure may not be linked, but taking steps to reduce your stress can improve your general health, including your blood ...

  7. High blood pressure - what to ask your doctor

    Science.gov (United States)

    What to ask your doctor about high blood pressure; Hypertension - what to ask your doctor ... problems? What medicines am I taking to treat high blood pressure? Do they have any side effects? What should ...

  8. Interdiffusion of krypton and xenon in high-pressure helium

    International Nuclear Information System (INIS)

    Campana, R.J.; Jensen, D.D.; Epstein, B.D.; Hudson, R.G.; Baldwin, N.L.

    1980-01-01

    The interdiffusion of gaseous fission products in high-pressure helium is an important factor in the control of radioactivity in gas-cooled fast breeder reactors (GCFRs). As presently conceived, GCFRs use pressure-equalized and vented fuel in which fission gases released from the solid matrix oxide fuel are transported through the fuel rod interstices and internal fission product traps to the fuel assembly vents, where they are swept away to external traps and storage. Since the predominant transport process under steady-state operating conditions is interdiffusion of gaseous fission products in helium, the diffusion properties of krypton-helium and xenon-helium couples have been measured over the range of GCFR temperature and pressure conditions ( -1 ) and expected temperature dependence to the 1.66 power (Tsup(1.66)) at lower pressures and temperatures. Additional work is in progress to measure the behaviour of the krypton-helium and xenon-helium couples in GCFR fuel rod charcoal delay traps. (author)

  9. Future directions in high-pressure neutron diffraction

    Science.gov (United States)

    Guthrie, M.

    2015-04-01

    The ability to manipulate structure and properties using pressure has been well known for many centuries. Diffraction provides the unique ability to observe these structural changes in fine detail on lengthscales spanning atomic to nanometre dimensions. Amongst the broad suite of diffraction tools available today, neutrons provide unique capabilities of fundamental importance. However, to date, the growth of neutron diffraction under extremes of pressure has been limited by the weakness of available sources. In recent years, substantial government investments have led to the construction of a new generation of neutron sources while existing facilities have been revitalized by upgrades. The timely convergence of these bright facilities with new pressure-cell technologies suggests that the field of high-pressure (HP) neutron science is on the cusp of substantial growth. Here, the history of HP neutron research is examined with the hope of gleaning an accurate prediction of where some of these revolutionary capabilities will lead in the near future. In particular, a dramatic expansion of current pressure-temperature range is likely, with corresponding increased scope for extreme-conditions science with neutron diffraction. This increase in coverage will be matched with improvements in data quality. Furthermore, we can also expect broad new capabilities beyond diffraction, including in neutron imaging, small angle scattering and inelastic spectroscopy.

  10. Sewage sludge solubilization by high-pressure homogenization.

    Science.gov (United States)

    Zhang, Yuxuan; Zhang, Panyue; Guo, Jianbin; Ma, Weifang; Fang, Wei; Ma, Boqiang; Xu, Xiangzhe

    2013-01-01

    The behavior of sludge solubilization using high-pressure homogenization (HPH) treatment was examined by investigating the sludge solid reduction and organics solubilization. The sludge volatile suspended solids (VSS) decreased from 10.58 to 6.67 g/L for the sludge sample with a total solids content (TS) of 1.49% after HPH treatment at a homogenization pressure of 80 MPa with four homogenization cycles; total suspended solids (TSS) correspondingly decreased from 14.26 to 9.91 g/L. About 86.15% of the TSS reduction was attributed to the VSS reduction. The increase of homogenization pressure from 20 to 80 MPa or homogenization cycle number from 1 to 4 was favorable to the sludge organics solubilization, and the protein and polysaccharide solubilization linearly increased with the soluble chemical oxygen demand (SCOD) solubilization. More proteins were solubilized than polysaccharides. The linear relationship between SCOD solubilization and VSS reduction had no significant change under different homogenization pressures, homogenization cycles and sludge solid contents. The SCOD of 1.65 g/L was solubilized for the VSS reduction of 1.00 g/L for the three experimental sludge samples with a TS of 1.00, 1.49 and 2.48% under all HPH operating conditions. The energy efficiency results showed that the HPH treatment at a homogenization pressure of 30 MPa with a single homogenization cycle for the sludge sample with a TS of 2.48% was the most energy efficient.

  11. Effect of high pressure on mesophilic lactic fermentation streptococci

    Energy Technology Data Exchange (ETDEWEB)

    Reps, A; Kuzmicka, M; Wisniewska, K [Chair of Food Biotechnology, University of Warmia and Mazury, ul. Heweliusza 1, 10-724 Olsztyn (Poland)], E-mail: arnold.reps@uwm.edu.pl

    2008-07-15

    The research concerned the effect of high pressure on mesophilic lactic fermentation streptococci, present in two cheese-making commercial inocula produced by Christian-Hansen. Water solutions of inocula were pressurized at 50-800 MPa, at room temperature, for 30-120 min. Pressurization at 50-100 MPa slightly increased or reduced the number of lactic streptococci, depending on the inoculum and pressurization time. Pressurization at 200 MPa caused a reduction in the number of streptococci by over 99.9%, whereas the pressure of 400 MPa and above almost completely inactivated streptococci. Pressurization also reduced the dynamics of microorganism growth and acidification, to the degree depending on the pressure.

  12. Natural Circulation Characteristics at Low-Pressure Conditions through PANDA Experiments and ATHLET Simulations

    OpenAIRE

    Paladino, Domenico; Huggenberger, Max; Schäfer, Frank

    2008-01-01

    Natural circulation characteristics at low pressure/low power have been studied by performing experimental investigations and numerical simulations. The PANDA large-scale facility was used to provide valuable, high quality data on natural circulation characteristics as a function of several parameters and for a wide range of operating conditions. The new experimental data allow for testing and improving the capabilities of the thermal-hydraulic computer codes to be used for treating natural c...

  13. Subnanosecond breakdown in high-pressure gases

    Science.gov (United States)

    Naidis, George V.; Tarasenko, Victor F.; Babaeva, Natalia Yu; Lomaev, Mikhail I.

    2018-01-01

    Pulsed discharges in high-pressure gases are of considerable interest as sources of nonequilibrium plasma for various technological applications: pollution control, pumping of laser media, plasma-assisted combustion, etc. Recently, attention has been attracted to the use of subnanosecond voltage fronts, producing diffuse discharges with radii of several millimeters. Such plasma structures, similar to pulsed glow discharges, are of special interest for applications due to quasi-uniformity of plasma parameters in relatively large gas volumes. This review presents the results of experimental and computational study of subnanosecond diffuse discharge formation. A description of generators of short high-voltage pulses with subnanosecond fronts and of discharge setups is given. Diagnostic methods for the measurement of various discharge parameters with high temporal and spatial resolution are described. Obtained experimental data on plasma properties for a wide range of governing factors are discussed. A review of various theoretical approaches used for computational study of the dynamics and structure of fast ionization waves is given; the applicability of conventional fluid streamer models for simulation of subnanosecond ionization waves is discussed. Calculated spatial-temporal profiles of plasma parameters during streamer propagation are presented. The efficiency of subnanosecond discharges for the production of reactive species is evaluated. On the basis of the comparison of simulation results and experimental data the effects of various factors (voltage rise time, polarity, etc.) on discharge characteristics are revealed. The major physical phenomena governing the properties of subnanosecond breakdown are analyzed.

  14. High pressure apparatus transport properties study in high magnetic field

    Czech Academy of Sciences Publication Activity Database

    Honda, F.; Sechovský, V.; Mikulina, O.; Kamarád, Jiří; Alsmadi, A. M.; Nakotte, H.; Lacerda, A. H.

    2002-01-01

    Roč. 16, 20, 21 & 22 (2002), s. 3330-3333 ISSN 0217-9792 R&D Projects: GA ČR GP202/01/D045; GA ČR GA202/00/1217; GA MŠk ME 165 Grant - others:NSF(XX) DMR-0094241 Institutional research plan: CEZ:AV0Z1010914 Keywords : high-pressure apparatus Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 0.604, year: 2002

  15. Remaining life assessment of a high pressure turbine rotor

    International Nuclear Information System (INIS)

    Nguyen, Ninh; Little, Alfie

    2012-01-01

    This paper describes finite element and fracture mechanics based modelling work that provides a useful tool for evaluation of the remaining life of a high pressure (HP) steam turbine rotor that had experienced thermal fatigue cracking. An axis-symmetrical model of a HP rotor was constructed. Steam temperature, pressure and rotor speed data from start ups and shut downs were used for the thermal and stress analysis. Operating history and inspection records were used to benchmark the damage experienced by the rotor. Fracture mechanics crack growth analysis was carried out to evaluate the remaining life of the rotor under themal cyclic loading conditions. The work confirmed that the fracture mechanics approach in conjunction with finite element modelling provides a useful tool for assessing the remaining life of high temperature components in power plants.

  16. 30 CFR 56.13021 - High-pressure hose connections.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false High-pressure hose connections. 56.13021... and Boilers § 56.13021 High-pressure hose connections. Except where automatic shutoff valves are used, safety chains or other suitable locking devices shall be used at connections to machines of high-pressure...

  17. 76 FR 38697 - High Pressure Steel Cylinders From China

    Science.gov (United States)

    2011-07-01

    ... imports from China of high pressure steel cylinders, provided for in subheading 7311.00.00 of the... threatened with material injury by reason of LTFV and subsidized imports of high pressure steel cylinders... contained in USITC Publication 4241 (July 2011), entitled High Pressure Steel Cylinders from China...

  18. 77 FR 37712 - High Pressure Steel Cylinders From China

    Science.gov (United States)

    2012-06-22

    ...), that an industry in the United States is materially injured by reason of imports of high pressure steel... preliminary determinations by Commerce that imports of high pressure steel cylinders from China were... Publication 4328 (June 2012), entitled High Pressure Steel Cylinders from China: Investigation Nos. 701-TA-480...

  19. Design of experimental system for supercritical CO2 fracturing under confining pressure conditions

    Science.gov (United States)

    Wang, H.; Lu, Q.; Li, X.; Yang, B.; Zheng, Y.; Shi, L.; Shi, X.

    2018-03-01

    Supercritical CO2 has the characteristics of low viscosity, high diffusion and zero surface tension, and it is considered as a new fluid for non-polluting and non-aqueous fracturing which can be used for shale gas development. Fracturing refers to a method of utilizing the high-pressure fluid to generate fractures in the rock formation so as to improve the oil and gas flow conditions and increase the oil and gas production. In this article, a new type of experimental system for supercritical CO2 fracturing under confining pressure conditions is designed, which is based on characteristics of supercritical CO2, shale reservoir and down-hole environment. The experimental system consists of three sub-systems, including supercritical CO2 generation system, supercritical CO2 fracturing system and data analysis system. It can be used to simulate supercritical CO2 fracturing under geo-stress conditions, thus to study the rock initiation pressure, the formation of the rock fractures, fractured surface morphology and so on. The experimental system has successfully carried out a series of supercritical CO2 fracturing experiments. The experimental results confirm the feasibility of the experimental system and the high efficiency of supercritical CO2 in fracturing tight rocks.

  20. A test facility for heat transfer, pressure drop and stability studies under supercritical conditions

    International Nuclear Information System (INIS)

    Sharma, Manish; Pilkhwal, D.S.; Jana, S.S.; Vijayan, P.K.

    2013-02-01

    Supercritical water (SCW) exhibits excellent heat transfer characteristics and high volumetric expansion coefficient (hence high mass flow rates in natural circulation systems) near pseudo-critical temperature. SCW is being considered as a coolant in some advanced nuclear reactor designs on account of its potential to offer high thermal efficiency, compact size, elimination of steam generator, separator and dryer, making it economically competitive. The elimination of phase change results in elimination of the Critical Heat Flux (CHF) phenomenon. Cooling a reactor at full power with natural instead of forced circulation is generally considered as enhancement of passive safety. In view of this, it is essential to study natural circulation, heat transfer and pressure drop characteristics of supercritical fluids. Carbon-dioxide can be considered to be a good simulant of water for natural circulation at supercritical conditions since the density and viscosity variation of carbon-dioxide follows a parallel curve as that of water at supercritical conditions. Hence, a supercritical pressure natural circulation loop (SPNCL) has been set up in Hall-7, BARC to investigate the heat transfer, pressure drop and stability characteristics of supercritical carbon-dioxide under natural circulation conditions. The details of the experimental facility are presented in this report. (author)

  1. High pressure chemistry of red phosphorus by photoactivated simple molecules

    Science.gov (United States)

    Ceppatelli, Matteo; Bini, Roberto; Fanetti, Samuele; Caporali, Maria; Peruzzini, Maurizio

    2013-06-01

    High pressure (HP) is very effective in reducing intermolecular distances and inducing unexpected chemical reactions. In particular the photoactivation of the reactants in HP conditions can lead to very efficient and selective processes. The chemistry of phosphorus is currently based on the white molecular form. The red polymeric allotrope, despite more stable and much less toxic, has not attracted much attention so far. However, switching from the white to the red form would benefit any industrial procedure, especially from an environmental point of view. On the other side, water and ethanol are renewable, environmental friendly and largely available molecules, usable as reactants and photoactivators in HP conditions. Here we report a study on the HP photoinduced reactivity of red phosphorus with water and ethanol, showing the possibility of very efficient and selective processes, leading to molecular hydrogen and valuable phosphorus compounds. The reactions have been studied by means of FTIR and Raman spectroscopy and pressure has been generated using DAC and SAC. HP reactivity has been activated by the two-photon absorption of near-UV wavelengths and occured in total absence of solvents, catalysts and radical initiators, at room T and mild pressure conditions (0.2-1.5 GPa).

  2. Single particle studies of black liquor gasification under pressurized conditions

    Energy Technology Data Exchange (ETDEWEB)

    Whitty, K; Backman, R; Hupa, M; Backman, P; Ek, P; Hulden, S T; Kullberg, M; Sorvari, V

    1997-10-01

    The purpose of this project is to provide experimental data relevant to pressurized black liquor gasification concepts. Specifically, the following two goals will be achieved: Data on swelling, char yields and component release during pressurized pyrolysis of small samples of black liquor will be obtained. The reactivity and physical behavior of single black liquor droplets during simultaneous pyrolysis and gasification will be investigated. The structure and composition of black liquor char during formation and conversion will be studied. (orig.)

  3. Cavitation and primary atomization in real injectors at low injection pressure condition

    Science.gov (United States)

    Dumouchel, Christophe; Leboucher, Nicolas; Lisiecki, Denis

    2013-06-01

    This experimental work investigates the influence of the geometry of GDI devices on primary atomization processes under low injection pressure and reduced back pressure. These pressure conditions ensure cavitating flows and observable atomization processes. Measurements include mass flux, structure velocity from high-speed visualizations and spray characterization with a laser diffraction technique. Super-cavitation regime and cavitation string, which have their own influence on the mass flux, develop independently in different injector regions. These regimes impact the flow pattern in the orifice and the subsequent atomization process. A possible interaction between cavitation string and super-cavitation is found to promote a hydraulic-flip-like regime and to deteriorate atomization quality. As far as the geometry of the injector is concerned, the profile of the orifice inlet and the roughness of the sac volume region are found to be important geometrical characteristics.

  4. High selection pressure promotes increase in cumulative adaptive culture.

    Directory of Open Access Journals (Sweden)

    Carolin Vegvari

    Full Text Available The evolution of cumulative adaptive culture has received widespread interest in recent years, especially the factors promoting its occurrence. Current evolutionary models suggest that an increase in population size may lead to an increase in cultural complexity via a higher rate of cultural transmission and innovation. However, relatively little attention has been paid to the role of natural selection in the evolution of cultural complexity. Here we use an agent-based simulation model to demonstrate that high selection pressure in the form of resource pressure promotes the accumulation of adaptive culture in spite of small population sizes and high innovation costs. We argue that the interaction of demography and selection is important, and that neither can be considered in isolation. We predict that an increase in cultural complexity is most likely to occur under conditions of population pressure relative to resource availability. Our model may help to explain why culture change can occur without major environmental change. We suggest that understanding the interaction between shifting selective pressures and demography is essential for explaining the evolution of cultural complexity.

  5. High pressure inactivation of Brettanomyces bruxellensis in red wine.

    Science.gov (United States)

    van Wyk, Sanelle; Silva, Filipa V M

    2017-05-01

    Brettanomyces bruxellensis ("Brett") is a major spoilage concern for the wine industry worldwide, leading to undesirable sensory properties. Sulphur dioxide, is currently the preferred method for wine preservation. However, due to its negative effects on consumers, the use of new alternative non-thermal technologies are increasingly being investigated. The aim of this study was to determine and model the effect of high pressure processing (HPP) conditions and yeast strain on the inactivation of "Brett" in Cabernet Sauvignon wine. Processing at 200 MPa for 3 min resulted in 5.8 log reductions. However higher pressure is recommended to achieve high throughput in the wine industry, for example >6.0 log reductions were achieved after 400 MPa for 5 s. The inactivation of B. bruxellensis is pressure and time dependent, with increased treatment time and pressure leading to increased yeast inactivation. It was also found that yeast strain had a significant effect on HPP inactivation, with AWRI 1499 being the most resistant strain. The Weibull model successfully described the HPP "Brett" inactivation. HPP is a viable alternative for the inactivation of B. bruxellensis in wine, with the potential to reduce the industry's reliance on sulphur dioxide. Copyright © 2016 Elsevier Ltd. All rights reserved.

  6. The development of an auto-sealing system using an electrically shrinkable tube under a low-pressure condition

    Energy Technology Data Exchange (ETDEWEB)

    Okano, Yoshihiro; Kitagawa, Takao [NKK Corp, Tsu, Mie (Japan); Shoji, Norio [NKK Corp., Yokohama (Japan); Namioka, Toshiyuki [Nippon Kokan Koji Corp., Yokohama (Japan). Research and Development Dept.; Komura, Minoru [Nitto Denko Corp., Fukaya, Saitama (Japan)

    1997-04-01

    This article describes the development of a system to create high quality, automatic sealing of field joints of polyethylene coated pipelines. The system uses a combination of an electrically heated shrinkable tube and a low-pressure chamber. The self-heating shrinkable tube includes electric heater wires that heat when connected to electricity. A method was developed to eliminate air trapped between the tube and the steel pipe by shrinking the tube under a low-pressure condition. The low-pressure condition was automatic and easily attained by using a vacuum chamber. It was verified that the system produced high quality sealing of the field joints.

  7. High pressure dielectric studies on the structural and orientational glass.

    Science.gov (United States)

    Kaminska, E; Tarnacka, M; Jurkiewicz, K; Kaminski, K; Paluch, M

    2016-02-07

    High pressure dielectric studies on the H-bonded liquid D-glucose and Orientationally Disordered Crystal (ODIC) 1,6-anhydro-D-glucose (levoglucosan) were carried out. It was shown that in both compounds, the structural relaxation is weakly sensitive to compression. It is well reflected in the low pressure coefficient of the glass transition and orientational glass transition temperatures which is equal to 60 K/GPa for both D-glucose and 1,6-anhydro-D-glucose. Although it should be noted that ∂Tg(0)/∂p evaluated for the latter compound seems to be enormously high with respect to other systems forming ODIC phase. We also found that the shape of the α-loss peak stays constant for the given relaxation time independently on the thermodynamic condition. Consequently, the Time Temperature Pressure (TTP) rule is satisfied. This experimental finding seems to be quite intriguing since the TTP rule was shown to work well in the van der Waals liquids, while in the strongly associating compounds, it is very often violated. We have also demonstrated that the sensitivity of the structural relaxation process to the temperature change measured by the steepness index (mp) drops with pressure. Interestingly, this change is much more significant in the case of D-glucose with respect to levoglucosan, where the fragility changes only slightly with compression. Finally, kinetics of ODIC-crystal phase transition was studied at high compression. It is worth mentioning that in the recent paper, Tombari and Johari [J. Chem. Phys. 142, 104501 (2015)] have shown that ODIC phase in 1,6-anhydro-D-glucose is stable in the wide range of temperatures and there is no tendency to form more ordered phase at ambient pressure. On the other hand, our isochronal measurements performed at varying thermodynamic conditions indicated unquestionably that the application of pressure favors solid (ODIC)-solid (crystal) transition in 1,6-anhydro-D-glucose. This result mimics the impact of pressure on the

  8. Photoluminescence study of Congo red molecules under high pressure

    International Nuclear Information System (INIS)

    Wang, Z.P.; Zhang, Z.M.; Ding, Z.J.

    2007-01-01

    Pressure-induced changes on fluorescence spectra of Congo red molecules were examined up to 8.7 GPa using a diamond anvil cell at room temperature. The spectra changes are demonstrated to be sensitive to the pressure and solvent conditions. At hydrostatic pressure and with a solvent used as a pressure transmitting medium the fluorescence spectra show increase of intensity with elevated pressure up to about 2.3 GPa and then drop at higher pressures. For Congo red crystal under quasi-hydrostatic condition without solvent the fluorescence intensity decreases monotonically and the lower energy band becomes dominant with the pressure increasing. The three vibronic bands show red shifts with increase of pressure

  9. Single stage high pressure centrifugal slurry pump

    Science.gov (United States)

    Meyer, John W.; Bonin, John H.; Daniel, Arnold D.

    1984-03-27

    Apparatus is shown for feeding a slurry to a pressurized housing. An impeller that includes radial passages is mounted in the loose fitting housing. The impeller hub is connected to a drive means and a slurry supply means which extends through the housing. Pressured gas is fed into the housing for substantially enveloping the impeller in a bubble of gas.

  10. Recombination times in germanium under high pressure

    International Nuclear Information System (INIS)

    Kuyt, J.H.

    1975-01-01

    The influence of pressure on a well defined recombination process was studied. The centres were introduced by γirradiation and the lifetime determined by the decay time of photoconductivity. An optical pressure vessel is described which allows for a hydrostatic variation of 3000 bars. The diffusion constant and lifetime measurements are presented and analysed. (V.J.C.)

  11. Multiple scaling power in liquid gallium under pressure conditions

    Energy Technology Data Exchange (ETDEWEB)

    Li, Renfeng; Wang, Luhong; Li, Liangliang; Yu, Tony; Zhao, Haiyan; Chapman, Karena W.; Rivers, Mark L.; Chupas, Peter J.; Mao, Ho-kwang; Liu, Haozhe

    2017-06-01

    Generally, a single scaling exponent, Df, can characterize the fractal structures of metallic glasses according to the scaling power law. However, when the scaling power law is applied to liquid gallium upon compression, the results show multiple scaling exponents and the values are beyond 3 within the first four coordination spheres in real space, indicating that the power law fails to describe the fractal feature in liquid gallium. The increase in the first coordination number with pressure leads to the fact that first coordination spheres at different pressures are not similar to each other in a geometrical sense. This multiple scaling power behavior is confined within a correlation length of ξ ≈ 14–15 Å at applied pressure according to decay of G(r) in liquid gallium. Beyond this length the liquid gallium system could roughly be viewed as homogeneous, as indicated by the scaling exponent, Ds, which is close to 3 beyond the first four coordination spheres.

  12. 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

  13. Micromachined capacitive pressure sensor with signal conditioning electronics

    DEFF Research Database (Denmark)

    Fragiacomo, Giulio

    signal) of the device. Fusion bonding of two wafers has been used in order to obtain the cavities, this is also the only non-standard cleanroom process involved in the fabrication of the transducers. The device developed can measure absolute pressures from 0 to 10 bar with sensitivity up to 80 p...... characterized and presented at Grundfos Direct Sensors A/S and constitute the preliminary work for a new product which is intended target the low power or wireless pressure sensor for harsh environment market....

  14. High Pressure Laminates with Antimicrobial Properties

    Directory of Open Access Journals (Sweden)

    Sandra Magina

    2016-02-01

    Full Text Available High-pressure laminates (HPLs are durable, resistant to environmental effects and good cost-benefit decorative surface composite materials with special properties tailored to meet market demand. In the present work, polyhexamethylene biguanide (PHMB was incorporated for the first time into melamine-formaldehyde resin (MF matrix on the outer layer of HPLs to provide them antimicrobial properties. Chemical binding of PHMB to resin matrix was detected on the surface of produced HPLs by attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR. Antimicrobial evaluation tests were carried out on the ensuing HPLs doped with PHMB against gram-positive Listeria innocua and gram-negative Escherichia coli bacteria. The results revealed that laminates prepared with 1.0 wt % PHMB in MF resin were bacteriostatic (i.e., inhibited the growth of microorganisms, whereas those prepared with 2.4 wt % PHMB in MF resin exhibited bactericidal activity (i.e., inactivated the inoculated microorganisms. The results herein reported disclose a promising strategy for the production of HPLs with antimicrobial activity without affecting basic intrinsic quality parameters of composite material.

  15. Automated high pressure cell for pressure jump x-ray diffraction.

    Science.gov (United States)

    Brooks, Nicholas J; Gauthe, Beatrice L L E; Terrill, Nick J; Rogers, Sarah E; Templer, Richard H; Ces, Oscar; Seddon, John M

    2010-06-01

    A high pressure cell for small and wide-angle x-ray diffraction measurements of soft condensed matter samples has been developed, incorporating a fully automated pressure generating network. The system allows both static and pressure jump measurements in the range of 0.1-500 MPa. Pressure jumps can be performed as quickly as 5 ms, both with increasing and decreasing pressures. Pressure is generated by a motorized high pressure pump, and the system is controlled remotely via a graphical user interface to allow operation by a broad user base, many of whom may have little previous experience of high pressure technology. Samples are loaded through a dedicated port allowing the x-ray windows to remain in place throughout an experiment; this facilitates accurate subtraction of background scattering. The system has been designed specifically for use at beamline I22 at the Diamond Light Source, United Kingdom, and has been fully integrated with the I22 beamline control systems.

  16. Automated high pressure cell for pressure jump x-ray diffraction

    Energy Technology Data Exchange (ETDEWEB)

    Brooks, Nicholas J.; Gauthe, Beatrice L. L. E.; Templer, Richard H.; Ces, Oscar; Seddon, John M. [Department of Chemistry, Imperial College London, South Kensington Campus, London SW7 2AZ (United Kingdom); Terrill, Nick J. [Diamond Light Source, Harwell Science and Innovation Campus, Didcot, Oxfordshire OX11 0DE (United Kingdom); Rogers, Sarah E. [ISIS, Rutherford Appleton Laboratory, Harwell Science and Innovation Campus, Didcot, Oxfordshire OX11 0QX (United Kingdom)

    2010-06-15

    A high pressure cell for small and wide-angle x-ray diffraction measurements of soft condensed matter samples has been developed, incorporating a fully automated pressure generating network. The system allows both static and pressure jump measurements in the range of 0.1-500 MPa. Pressure jumps can be performed as quickly as 5 ms, both with increasing and decreasing pressures. Pressure is generated by a motorized high pressure pump, and the system is controlled remotely via a graphical user interface to allow operation by a broad user base, many of whom may have little previous experience of high pressure technology. Samples are loaded through a dedicated port allowing the x-ray windows to remain in place throughout an experiment; this facilitates accurate subtraction of background scattering. The system has been designed specifically for use at beamline I22 at the Diamond Light Source, United Kingdom, and has been fully integrated with the I22 beamline control systems.

  17. Automated high pressure cell for pressure jump x-ray diffraction

    International Nuclear Information System (INIS)

    Brooks, Nicholas J.; Gauthe, Beatrice L. L. E.; Templer, Richard H.; Ces, Oscar; Seddon, John M.; Terrill, Nick J.; Rogers, Sarah E.

    2010-01-01

    A high pressure cell for small and wide-angle x-ray diffraction measurements of soft condensed matter samples has been developed, incorporating a fully automated pressure generating network. The system allows both static and pressure jump measurements in the range of 0.1-500 MPa. Pressure jumps can be performed as quickly as 5 ms, both with increasing and decreasing pressures. Pressure is generated by a motorized high pressure pump, and the system is controlled remotely via a graphical user interface to allow operation by a broad user base, many of whom may have little previous experience of high pressure technology. Samples are loaded through a dedicated port allowing the x-ray windows to remain in place throughout an experiment; this facilitates accurate subtraction of background scattering. The system has been designed specifically for use at beamline I22 at the Diamond Light Source, United Kingdom, and has been fully integrated with the I22 beamline control systems.

  18. Impact of high hydrostatic pressure on bacterial proteostasis.

    Science.gov (United States)

    Gayán, Elisa; Govers, Sander K; Aertsen, Abram

    2017-12-01

    High hydrostatic pressure (HHP) is an important factor that limits microbial growth in deep-sea ecosystems to specifically adapted piezophiles. Furthermore, HHP treatment is used as a novel food preservation technique because of its ability to inactivate pathogenic and spoilage bacteria while minimizing the loss of food quality. Disruption of protein homeostasis (i.e. proteostasis) as a result of HHP-induced conformational changes in ribosomes and proteins has been considered as one of the limiting factors for both microbial growth and survival under HHP conditions. This work therefore reviews the effects of sublethal (≤100MPa) and lethal (>100MPa) pressures on protein synthesis, structure, and functionality in bacteria. Furthermore, current understanding on the mechanisms adopted by piezophiles to maintain proteostasis in HHP environments and responses developed by atmospheric-adapted bacteria to protect or restore proteostasis after HHP exposure are discussed. Copyright © 2017 Elsevier B.V. All rights reserved.

  19. High cost of stage IV pressure ulcers.

    Science.gov (United States)

    Brem, Harold; Maggi, Jason; Nierman, David; Rolnitzky, Linda; Bell, David; Rennert, Robert; Golinko, Michael; Yan, Alan; Lyder, Courtney; Vladeck, Bruce

    2010-10-01

    The aim of this study was to calculate and analyze the cost of treatment for stage IV pressure ulcers. A retrospective chart analysis of patients with stage IV pressure ulcers was conducted. Hospital records and treatment outcomes of these patients were followed up for a maximum of 29 months and analyzed. Costs directly related to the treatment of pressure ulcers and their associated complications were calculated. Nineteen patients with stage IV pressure ulcers (11 hospital-acquired and 8 community-acquired) were identified and their charts were reviewed. The average hospital treatment cost associated with stage IV pressure ulcers and related complications was $129,248 for hospital-acquired ulcers during 1 admission, and $124,327 for community-acquired ulcers over an average of 4 admissions. The costs incurred from stage IV pressure ulcers are much greater than previously estimated. Halting the progression of early stage pressure ulcers has the potential to eradicate enormous pain and suffering, save thousands of lives, and reduce health care expenditures by millions of dollars. Copyright © 2010 Elsevier Inc. All rights reserved.

  20. 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.

  1. Sleep Deprivation: A Cause of High Blood Pressure?

    Science.gov (United States)

    ... it true that sleep deprivation can cause high blood pressure? Answers from Sheldon G. Sheps, M.D. Possibly. It's thought that ... hours a night could be linked to increased blood pressure. People who sleep five hours or less a ...

  2. High Pressure Electrochemical Oxygen Generation for ISS, Phase II

    Data.gov (United States)

    National Aeronautics and Space Administration — Giner, Inc. has developed an advanced high pressure electrochemical oxygen concentrator (EOC) that offers a simple alternative to the use of pressure swing...

  3. Collisional and radiative processes in high-pressure discharge plasmas

    Science.gov (United States)

    Becker, Kurt H.; Kurunczi, Peter F.; Schoenbach, Karl H.

    2002-05-01

    Discharge plasmas at high pressures (up to and exceeding atmospheric pressure), where single collision conditions no longer prevail, provide a fertile environment for the experimental study of collisions and radiative processes dominated by (i) step-wise processes, i.e., the excitation of an already excited atomic/molecular state and by (ii) three-body collisions leading, for instance, to the formation of excimers. The dominance of collisional and radiative processes beyond binary collisions involving ground-state atoms and molecules in such environments allows for many interesting applications of high-pressure plasmas such as high power lasers, opening switches, novel plasma processing applications and sputtering, absorbers and reflectors for electromagnetic waves, remediation of pollutants and waste streams, and excimer lamps and other noncoherent vacuum-ultraviolet light sources. Here recent progress is summarized in the use of hollow cathode discharge devices with hole dimensions in the range 0.1-0.5 mm for the generation of vacuum-ultraviolet light.

  4. Monitoring operational conditions of vehicle tyre pressure levels and ...

    African Journals Online (AJOL)

    Compliance with vehicle tyre inflation pressure and tread depth standard specifications and legal requirements were monitored by survey study in Kumasi Metropolis, Ghana. The survey covered 400 vehicles, comprising cars (28 %), medium buses (25 %), large capacity buses (15 %) and trucks (32 %). There were wide ...

  5. High-temperature fiber optic pressure sensor

    Science.gov (United States)

    Berthold, J. W.

    1984-01-01

    Attention is given to a program to develop fiber optic methods to measure diaphragm deflection. The end application is intended for pressure transducers capable of operating to 540 C. In this paper are reported the results of a laboratory study to characterize the performance of the fiber-optic microbend sensor. The data presented include sensitivity and spring constant. The advantages and limitations of the microbend sensor for static pressure measurement applications are described. A proposed design is presented for a 540 C pressure transducer using the fiber optic microbend sensor.

  6. Effects of atmospheric pressure conditions on flow rate of an elastomeric infusion pump.

    Science.gov (United States)

    Wang, Jong; Moeller, Anna; Ding, Yuanpang Samuel

    2012-04-01

    The effects of pressure conditions, both hyperbaric and hypobaric, on the flow rate of an elastomeric infusion pump were investigated. The altered pressure conditions were tested with the restrictor outlet at two different conditions: (1) at the same pressure condition as the Infusor elastomeric balloon and (2) with the outlet exposed to ambient conditions. Five different pressure conditions were tested. These included ambient pressure (98-101 kilopascals [kPa]) and test pressures controlled to be 10 or 20 kPa below or 75 or 150 kPa above the ambient pressure. A theoretical calculation based on the principles of fluid mechanics was also used to predict the pump's flow rate at various ambient conditions. The conditions in which the Infusor elastomeric pump and restrictor outlet were at the same pressure gave rise to average flow rates within the ±10% tolerance of the calculated target flow rate of 11 mL/hr. The flow rate of the Infusor pump decreased when the pressure conditions changed from hypobaric to ambient. The flow rate increased when the pressure conditions changed from hyperbaric to ambient. The flow rate of the Infusor elastomeric pump was not affected when the balloon reservoir and restrictor outlet were at the same pressure. The flow rate varied from 58.54% to 377.04% of the labeled flow rate when the pressure applied to the reservoir varied from 20 kPa below to 150 kPa above the pressure applied to the restrictor outlet, respectively. The maximum difference between observed flow rates and those calculated by applying fluid mechanics was 4.9%.

  7. High pressure water electrolysis for space station EMU recharge

    Science.gov (United States)

    Lance, Nick; Puskar, Michael; Moulthrop, Lawrence; Zagaja, John

    1988-01-01

    A high pressure oxygen recharge system (HPORS), is being developed for application on board the Space Station. This electrolytic system can provide oxygen at up to 6000 psia without a mechanical compressor. The Hamilton standard HPORS based on a solid polymer electrolyte system is an extension of the much larger and succesful 3000 psia system of the U.S. Navy. Cell modules have been successfully tested under conditions beyond which spacecraft may encounter during launch. The control system with double redundancy and mechanical backups for all electronically controlled components is designed to ensure a safe shutdown.

  8. GENERATION OF HIGH SHOCK PRESSURES BY LASER PULSES

    OpenAIRE

    Romain , J.

    1984-01-01

    Aspects of laser generated high shock pressures and results obtained over the last years are reviewed. Shock pressures up to 5 TPa inferred from shock velocity measurements are reported. Effects of laser wavelength, intensity and 2-D plasma expansion on the generated shock pressure are discussed. The hydrodynamic efficiency determined from various data including new results at 0,26 µm wavelength outlines the advantage of short wavelengths for producing very high pressures. The possibility of ...

  9. 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...

  10. Experimental characterization of gasoline sprays under highly evaporating conditions

    Science.gov (United States)

    Khan, Muhammad Mahabat; Sheikh, Nadeem Ahmed; Khalid, Azfar; Lughmani, Waqas Akbar

    2018-05-01

    An experimental investigation of multistream gasoline sprays under highly evaporating conditions is carried out in this paper. Temperature increase of fuel and low engine pressure could lead to flash boiling. The spray shape is normally modified significantly under flash boiling conditions. The spray plumes expansion along with reduction in the axial momentum causes the jets to merge and creates a low-pressure area below the injector's nozzle. These effects initiate the collapse of spray cone and lead to the formation of a single jet plume or a big cluster like structure. The collapsing sprays reduces exposed surface and therefore they last longer and subsequently penetrate more. Spray plume momentum increase, jet plume reduction and spray target widening could delay or prevent the closure condition and limit the penetration (delayed formation of the cluster promotes evaporation). These spray characteristics are investigated experimentally using shadowgraphy, for five and six hole injectors, under various boundary conditions. Six hole injectors produce more collapsing sprays in comparison to five hole injector due to enhanced jet to jet interactions. The spray collapse tendency reduces with increase in injection pressure due high axial momentum of spray plumes. The spray evaporation rates of five hole injector are observed to be higher than six hole injectors. Larger spray cone angles of the six hole injectors promote less penetrating and less collapsing sprays.

  11. 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.

  12. Optimal heat rejection pressure in transcritical carbon dioxide air conditioning and heat pump systems

    DEFF Research Database (Denmark)

    Liao, Shengming; Jakobsen, Arne

    1998-01-01

    Due to the urgent need for environmentally benign refrigerants, the use of the natural substance carbon dioxide in refrigeration systems has gained more and more attention. In systems such as automobile air-conditioners and heat pumps, owing to the relatively high heat rejection temperatures, the...... dioxide air conditioning or heat pump systems and for intelligent controlling such systems.......Due to the urgent need for environmentally benign refrigerants, the use of the natural substance carbon dioxide in refrigeration systems has gained more and more attention. In systems such as automobile air-conditioners and heat pumps, owing to the relatively high heat rejection temperatures......, the cycles using carbon dioxide as refrigerant will have to operate in the transcritical area. In a transcritical carbon dioxide system, there is an optimal heat rejection pressure that gives a maximum COP. In this paper, it is shown that the value of this optimal heat rejection pressure mainly depends...

  13. 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.

  14. Microstructural Evidences of Intergranular Pressure Solution during Frictional Sliding at Hydrothermal Conditions

    Science.gov (United States)

    Ma, X.; Yao, S.; He, C.

    2017-12-01

    In the framework of rate- and state-dependent friction, velocity weakening is the result of a healing effect at intergranular contacts that is stronger than the instantaneous rate effect. Intergranular pressure solution has been proposed to be a feasible mechanism for the frictional healing effect (He et al., 2013), but to date no substantial evidences have been reported in related microstructures. In this study we report our reanalyses on samples of plagioclase gouge deformed at hydrothermal conditions with effective normal stresses of 100 MPa, 200 MPa, and 300 MPa, pore pressures of 30 MPa and 100 MPa, and temperatures from 100oC to 600oC. With an Inlens image detector in a scanning electron microscope, our focus is to find the evidences of the pressure solution processes during frictional sliding. As it has been difficult to observe the signatures of pressure solution during frictional sliding at the solution sites due to the short contact time of frequently-switching contact pairs, now we focus on the results of precipitation instead, which is the final process of pressure solution. With high magnification, we find the following evidences of intergranular pressure solution: 1) crystal growth as a result of precipitation is ubiquitously observed in deformed samples at temperatures above 200oC; 2) very fine-grained precipitated particles with flaky morphologies typically appear in intensely sheared regions and between relatively large particles in moderately sheared regions; 3) the precipitated grains are concentrated periodically in zones orientated at 45-50 degrees to the fault strike. These observations indicate that intergranular pressure solution is the dominant process responsible for the frictional healing effect.

  15. 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.

  16. Elasticity of stishovite at high pressure

    Science.gov (United States)

    Li, Baosheng; Rigden, Sally M.; Liebermann, Robert C.

    1996-08-01

    The elastic-wave velocities of stishovite, the rutile-structured polymorph of SiO 2, were measured to 3 GPa at room temperature in a piston cylinder apparatus using ultrasonic interferometry on polycrystalline samples. These polycrystalline samples (2-3 mm in length and diameter) were hot-pressed at 14 GPa and 1050°C in a 2000 ton uniaxial split-sphere apparatus (USSA-2000) using fused silica rods as starting material. They were characterized as low porosity (less than 1%), single phase, fine grained, free of cracks and preferred orientation, and acoustically isotropic by using density measurement, X-ray diffraction, scanning electron microscopy, and bench-top velocity measurements. On the basis of subsequent in situ X-ray diffraction study at high P and T on peak broadening on similar specimens, it is evident that the single crystal grains within these polycrystalline aggregates are well equilibrated and that these specimens are free of residual strain. P- and S-wave velocities measured at 1 atm are within 1.5% of the Hashin-Shtrikman bounds calculated from single-crystal elastic moduli. Measured pressure derivatives of the bulk and shear moduli, K' 0 = 5.3 ± 0.1 and G' 0 = 1.8 ± 0.1, are not unusual compared with values measured for other transition zone phases such as silicate spinel and majorite garnet. Isothermal compression curves calculated with the measured values of K0 and K' 0 agree well with experimental P-V data to 16 GPa. The experimental value of dG /dP is in excellent agreement with predictions based on elasticity systematics. Theoretical models are not yet able to replicate the measured values of K' 0 and G' 0.

  17. High-pressure system for Compton scattering experiments

    International Nuclear Information System (INIS)

    Oomi, G.; Honda, F.; Kagayama, T.; Itoh, F.; Sakurai, H.; Kawata, H.; Shimomura, O.

    1998-01-01

    High-pressure apparatus for Compton scattering experiments has been developed to study the momentum distribution of conduction electrons in metals and alloys at high pressure. This apparatus was applied to observe the Compton profile of metallic Li under pressure. It was found that the Compton profile at high pressure could be obtained within several hours by using this apparatus and synchrotron radiation. The result on the pressure dependence of the Fermi momentum of Li obtained here is in good agreement with that predicted from the free-electron model

  18. Advances in high pressure science and technology: proceedings of the fourth national conference on high pressure science and technology

    International Nuclear Information System (INIS)

    Yousuf, Mohammad; Subramanian, N.; Govinda Rajan, K.

    1997-09-01

    The proceedings of the fourth National Conference on High Pressure Science and Technology covers a wide area of research and development activities in the field of high pressure science and technology, broadly classified into the following themes: mechanical behaviour of materials; instrumentation and methods in high pressure research; pressure calibration, standards and safety aspects; phase transitions; shock induced reactions; mineral science, geophysics, geochemistry and planetary sciences; optical, electronic and transport properties; synthesis of materials; soft condensed matter physics and liquid crystals; computational methods in high pressure research. Papers relevant to INIS are indexed separately

  19. Modeling, Parameters Identification, and Control of High Pressure Fuel Cell Back-Pressure Valve

    Directory of Open Access Journals (Sweden)

    Fengxiang Chen

    2014-01-01

    Full Text Available The reactant pressure is crucial to the efficiency and lifespan of a high pressure PEMFC engine. This paper analyses a regulated back-pressure valve (BPV for the cathode outlet flow in a high pressure PEMFC engine, which can achieve precisely pressure control. The modeling, parameters identification, and nonlinear controller design of a BPV system are considered. The identified parameters are used in designing active disturbance rejection controller (ADRC. Simulations and extensive experiments are conducted with the xPC Target and show that the proposed controller can not only achieve good dynamic and static performance but also have strong robustness against parameters’ disturbance and external disturbance.

  20. New Developments in Deformation Experiments at High Pressure

    International Nuclear Information System (INIS)

    Durham, W B; Weidner, D J; Karato, S; Wang, Y

    2004-01-01

    Although the importance of rheological properties in controlling the dynamics and evolution of the whole mantle of Earth is well-recognized, experimental studies of rheological properties and deformation-induced microstructures have mostly been limited to low-pressure conditions. This is mainly a result of technical limitations in conducting quantitative rheological experiments under high-pressure conditions. A combination of factors is changing this situation. Increased resolution of composition and configuration of Earth's interior has created a greater demand for well-resolved laboratory measurement of the effects of pressure on the behavior of materials. Higher-strength materials have become readily available for containing high-pressure research devices, and new analytical capabilities--in particular very bright synchrotron X-ray sources--are now readily available to high-pressure researchers. One of the biggest issues in global geodynamics is the style of mantle convection and the nature of chemical differentiation associated with convectional mass transport. Although evidence for deep mantle circulation has recently been found through seismic tomography (e.g., van der Hilst et al. (1997)), complications in convection style have also been noted. They include (1) significant modifications of flow geometry across the mantle transition zone as seen from high resolution tomographic studies (Fukao et al. 1992; Masters et al. 2000; van der Hilst et al. 1991) and (2) complicated patterns of flow in the deep lower mantle (∼1500-2500 km), perhaps caused by chemical heterogeneity (Kellogg et al. 1999; van der Hilst and Karason 1999). These studies indicate that while large-scale circulation involving the whole mantle no doubt occurs, significant deviations from simple flow geometry are also present. Two mineral properties have strong influence on convection: (1) density and (2) viscosity (rheology) contrasts. In the past, the effects of density contrast have been

  1. 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.

  2. High Pressure, High Gradient RF Cavities for Muon Beam Cooling

    CERN Document Server

    Johnson, R P

    2004-01-01

    High intensity, low emittance muon beams are needed for new applications such as muon colliders and neutrino factories based on muon storage rings. Ionization cooling, where muon energy is lost in a low-Z absorber and only the longitudinal component is regenerated using RF cavities, is presently the only known cooling technique that is fast enough to be effective in the short muon lifetime. RF cavities filled with high-pressure hydrogen gas bring two advantages to the ionization technique: the energy absorption and energy regeneration happen simultaneously rather than sequentially, and higher RF gradients and better cavity breakdown behavior are possible than in vacuum due to the Paschen effect. These advantages and some disadvantages and risks will be discussed along with a description of the present and desired RF R&D efforts needed to make accelerators and colliders based on muon beams less futuristic.

  3. AMPTRACT: an algebraic model for computing pressure tube circumferential and steam temperature transients under stratified channel coolant conditions

    International Nuclear Information System (INIS)

    Gulshani, P.; So, C.B.

    1986-10-01

    In a number of postulated accident scenarios in a CANDU reactor, some of the horizontal fuel channels are predicted to experience periods of stratified channel coolant condition which can lead to a circumferential temperature gradient around the pressure tube. To study pressure tube strain and integrity under stratified flow channel conditions, it is, necessary to determine the pressure tube circumferential temperature distribution. This paper presents an algebraic model, called AMPTRACT (Algebraic Model for Pressure Tube TRAnsient Circumferential Temperature), developed to give the transient temperature distribution in a closed form. AMPTRACT models the following modes of heat transfer: radiation from the outermost elements to the pressure tube and from the pressure to calandria tube, convection between the fuel elements and the pressure tube and superheated steam, and circumferential conduction from the exposed to submerged part of the pressure tube. An iterative procedure is used to solve the mass and energy equations in closed form for axial steam and fuel-sheath transient temperature distributions. The one-dimensional conduction equation is then solved to obtain the pressure tube circumferential transient temperature distribution in a cosine series expansion. In the limit of large times and in the absence of convection and radiation to the calandria tube, the predicted pressure tube temperature distribution reduces identically to a parabolic profile. In this limit, however, radiation cannot be ignored because the temperatures are generally high. Convection and radiation tend to flatten the parabolic distribution

  4. Experimental Compressibility of Molten Hedenbergite at High Pressure

    Science.gov (United States)

    Agee, C. B.; Barnett, R. G.; Guo, X.; Lange, R. A.; Waller, C.; Asimow, P. D.

    2010-12-01

    Experiments using the sink/float method have bracketed the density of molten hedenbergite (CaFeSi2O6) at high pressures and temperatures. The experiments are the first of their kind to determine the compressibility of molten hedenbergite at high pressure and are part of a collaborative effort to establish a new database for an array of silicate melt compositions, which will contribute to the development of an empirically based predictive model that will allow calculation of silicate liquid density and compressibility over a wide range of P-T-X conditions where melting could occur in the Earth. Each melt composition will be measured using: (i) double-bob Archimedean method for melt density and thermal expansion at ambient pressure, (ii) sound speed measurements on liquids to constrain melt compressibility at ambient pressure, (iii) sink/float technique to measure melt density to 15 GPa, and (iv) shock wave measurements of P-V-E equation of state and temperature between 10 and 150 GPa. Companion abstracts on molten fayalite (Waller et al., 2010) and liquid mixes of hedenbergite-diopside and anorthite-hedenbergite-diopside (Guo and Lange, 2010) are also presented at this meeting. In the present study, the hedenbergite starting material was synthesized at the Experimental Petrology Lab, University of Michigan, where melt density, thermal expansion, and sound speed measurements were also carried out. The starting material has also been loaded into targets at the Caltech Shockwave Lab, and experiments there are currently underway. We report here preliminary results from static compression measurement performed at the Department of Petrology, Vrije Universiteit, Amsterdam, and the High Pressure Lab, Institute of Meteoritics, University of New Mexico. Experiments were carried out in Quick Press piston-cylinder devices and a Walker-style multi-anvil device. Sink/float marker spheres implemented were gem quality synthetic forsterite (Fo100), San Carlos olivine (Fo90), and

  5. Generalized enthalpy model of a high-pressure shift freezing process

    KAUST Repository

    Smith, N. A. S.; Peppin, S. S. L.; Ramos, A. M.

    2012-01-01

    High-pressure freezing processes are a novel emerging technology in food processing, offering significant improvements to the quality of frozen foods. To be able to simulate plateau times and thermal history under different conditions, in this work

  6. 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)

  7. High pressure oxidation of C2H4/NO mixtures

    DEFF Research Database (Denmark)

    Giménez-López, J.; Alzueta, M.U.; Rasmussen, C.T.

    2011-01-01

    An experimental and kinetic modeling study of the interaction between C2H4 and NO has been performed under flow reactor conditions in the intermediate temperature range (600–900K), high pressure (60bar), and for stoichiometries ranging from reducing to oxidizing conditions. The main reaction...... pathways of the C2H4/O2/NOx conversion, the capacity of C2H4 to remove NO, and the influence of the presence of NOx on the C2H4 oxidation are analyzed. Compared to the C2H4/O2 system, the presence of NOx shifts the onset of reaction 75–150K to lower temperatures. The mechanism of sensitization involves...... the reaction HOCH2CH2OO+NO→CH2OH+CH2O+NO2, which pushes a complex system of partial equilibria towards products. This is a confirmation of the findings of Doughty et al. [3] for a similar system at atmospheric pressure. Under reducing conditions and temperatures above 700K, a significant fraction of the NOx...

  8. 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)

  9. Cathode erosion in high-current high-pressure arc

    CERN Document Server

    Nemchinsky, V A

    2003-01-01

    Cathode erosion rate was experimentally investigated for two types of arcs: one with tungsten cathode in nitrogen atmosphere and one with hafnium cathode in oxygen atmosphere. Conditions were typical for plasma arc cutting systems: gas pressure from 2 to 5 atm, arc current from 200 to 400 A, gas flow rate from 50 to 130 litre min sup - sup 1. It was found that the actual cathode evaporation rate G is much lower than G sub 0 , the evaporation rate that follows from the Hertz-Knudsen formula: G = nu G sub 0. The difference is because some of the evaporated particles return back to the cathode. For conditions of our experiments, the factor nu could be as low as 0.01. It was shown experimentally that nu depends strongly on the gas flow pattern close to the cathode. In particular, swirling the gas increases nu many times. To explain the influence of gas swirling, model calculations of gas flows were performed. These calculations revealed difference between swirling and non-swirling flows: swirling the gas enhances...

  10. 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

  11. Polythiophene films obtained by polymerization under atmospheric pressure plasma conditions

    Energy Technology Data Exchange (ETDEWEB)

    Teslaru, T.; Topala, I., E-mail: ionut.topala@uaic.ro; Dobromir, M.; Pohoata, V.; Curecheriu, L.; Dumitrascu, N.

    2016-02-01

    The present work describes the experimental arrangement used to initiate polymerization reactions of thiophene monomer based on a dielectric barrier discharge with plane – parallel geometry, working at atmospheric pressure in argon, in turn to obtain conductive polymeric films for different applications. The resulting plasma polymerized polythiophene (pPTh) film was characterized by FT-IR, UV–Vis, XPS spectroscopy, AFM and contact angle measurements. Characterization of pPTh films showed a higher hydrophobic character and roughness, as compared with films obtained by chemical methods, and the thickness is depending on polymerization duration. Also it can conclude that our samples represent oxidised state of pPTh. As a possible application, it analysed in situ the iodine absorption phenomenon in the pPTh matrix and its time evolution by UV–Vis spectroscopy. The presence of iodine 3d{sub 5/2} and 3d{sub 3/2} peaks in the pPTh sample after absorption was identified by XPS spectroscopy. The hydrophobic pPTh film is transformed in a super hydrophilic film after absorption of iodine vapors. - Highlights: • We obtained polythiophene films (pPTh) by atmospheric pressure plasma technique. • The pPTh films showed a hydrophobic character and conducting properties. • The pPTh films were used as sensor for iodine vapors in biological environment.

  12. Announcement: National High Blood Pressure Education Month - May 2016.

    Science.gov (United States)

    2016-05-27

    May is National High Blood Pressure Education Month. High blood pressure (hypertension) is a major contributor to heart disease and stroke, two leading causes of death in the United States.* High blood pressure affects one third of U.S. adults, or approximately 75 million persons, yet approximately 11 million of these persons are not aware they have hypertension, and approximately 18 million are not being treated (unpublished data) (1,2).

  13. Safety regulation on high-pressure gas and gas business

    International Nuclear Information System (INIS)

    Kim, Du Yeoung; An, Dae Jun

    1978-09-01

    This book is divided into two parts. The first part introduces safety regulation on high-pressure gas, enforcement ordinance on safety regulation about high-pressure gas and enforcement regulation on safety regulation about high-pressure gas. The second part indicates regulations on gas business such as general rules, gas business gas supplies, using land, supervision, supple mentary rules and penalty. It has two appendixes on expected questions and questions during last years.

  14. Teaming Up Against High Blood Pressure PSA (:60)

    Centers for Disease Control (CDC) Podcasts

    Nearly one-third of American adults have high blood pressure, and more than half of them don’t have it under control. Simply seeing a doctor and taking medications isn’t enough for many people who have high blood pressure. A team-based approach by patients, health care systems, and health care providers is one of the best ways to treat uncontrolled high blood pressure.

  15. Magnetic structures of erbium under high pressure

    DEFF Research Database (Denmark)

    Kawano, S.; Lebech, B.; Achiwa, N.

    1993-01-01

    Neutron diffraction studies of the magnetic structures of erbium metal at 4.5 K and 11.5 kbar hydrostatic pressure have revealed that the transition to a conical structure at low temperatures is suppressed and that the cycloidal structure, with modulation vector Q congruent-to (2/7 2pi/c)c persists...

  16. Generation of high shock pressures by laser pulses

    Energy Technology Data Exchange (ETDEWEB)

    Romain, J.P. (GRECO ILM, Laboratoire d' Energetique et Detonique, E.N.S.M.A., 86 - Poitiers (France))

    1984-11-01

    Aspects of laser generated high shock pressures and results obtained over the last years are reviewed. Shock pressures up to 5 TPa inferred from shock velocity measurements are reported. Effects of laser wavelength, intensity and 2-D plasma expansion on the generated shock pressure are discussed. The hydrodynamic efficiency determined from various data including new results at 0,26 ..mu..m wavelength outlines the advantage of short wavelengths for producing very high pressures. The possibility of achieving shock pressures in the 10 TPa range with the use of the impedance match technique is examined.

  17. Generation of high shock pressures by laser pulses

    International Nuclear Information System (INIS)

    Romain, J.P.

    1984-01-01

    Aspects of laser generated high shock pressures and results obtained over the last years are reviewed. Shock pressures up to 5 TPa inferred from shock velocity measurements are reported. Effects of laser wavelength, intensity and 2-D plasma expansion on the generated shock pressure are discussed. The hydrodynamic efficiency determined from various data including new results at 0,26 μm wavelength outlines the advantage of short wavelengths for producing very high pressures. The possibility of achieving shock pressures in the 10 TPa range with the use of the impedance match technique is examined

  18. Vibrational spectroscopy at high external pressures the diamond anvil cell

    CERN Document Server

    Ferraro, John R

    1984-01-01

    Vibrational Spectroscopy at High External Pressures: The Diamond Anvil Cell presents the effects of high pressure on the vibrational properties of materials as accomplished in a diamond anvil cell (DAC). The DAC serves the dual purpose of generating the pressures and being transparent to infrared radiation, allowing the observation of changes caused by pressure. The optical probes highlighted will deal principally with infrared and Raman scattering, although some observations in the visible region will also be presented. The book begins with a discussion of the effects of pressure and pres

  19. Magnetization at high pressure in CeP

    Science.gov (United States)

    Naka, T.; Matsumoto, T.; Okayama, Y.; Môri, N.; Haga, Y.; Suzuki, T.

    1995-02-01

    We have investigated the pressure dependence of magnetization below 60 K up to 1.6 GPa in the low-carrier concentration system CeP showing two step transitions at T = TL and TH under high pressure. At high pressure, M( P, T) exhibits a maximum at around the lower transition temperature TL. This behavior implies that the magnetic state changes at TL. The pressure dependence of isothermal magnetization M( P) is different above and below TL. In fact, M( P) below TL exhibits a maximum at around 1.4 GPa, whereas M( P) above TL increases steeply with pressure up to 1.6 GPa.

  20. High pressure studies of fluorenone emission in plastic media

    International Nuclear Information System (INIS)

    Mitchell, D.J.; Schuster, G.B.; Drickamer, H.G.

    1977-01-01

    The energy and the quantum efficiency for fluorenone fluorescence in the crystalline state and in polymeric matrices was measured as a function of external pressure over the range 0--140 kbar. The application of high pressure induces changes in the quantum yield, which ranges from 0.001 at low pressure to a maximum of approx.0.1 at high pressure in hydrocarbon plastics. These results are interpreted as arising from the decrease in the energy of the lowest ππ excited singlet state relative to other relevant states as the external pressure is increased

  1. Proposed dedicated high pressure beam lines at CHESS

    International Nuclear Information System (INIS)

    Ruoff, A.L.; Vohra, Y.K.; Bassett, W.A.; Batterman, B.W.; Bilderback, D.H.

    1988-01-01

    An instrumentation proposal for dedicated high pressure beam lines at CHESS is described. It is the purpose of this proposed program to provide researchers in high pressure science with beam lines for X-ray diffraction studies in the megabar regime. This will involve radiation from a bending magnet as well as from a wiggler. Examples of the high pressure results up to 2.16 Mbar are shown. Diffraction patterns from bending magnet and wiggler beams are shown and compared. The need for this facility by the high pressure community is discussed. (orig.)

  2. Effect of high pressurized carbon dioxide on Escherichia coli ...

    African Journals Online (AJOL)

    Carbon dioxide at high pressure can retard microbial growth and sometimes kill microorganisms depending on values of applied pressure, temperature and exposure time. In this study the effect of high pressurised carbon dioxide (HPCD) on Escherichia coli was investigated. Culture of E. coli was subjected to high ...

  3. High-resolution thermal expansion measurements under helium-gas pressure

    Science.gov (United States)

    Manna, Rudra Sekhar; Wolf, Bernd; de Souza, Mariano; Lang, Michael

    2012-08-01

    We report on the realization of a capacitive dilatometer, designed for high-resolution measurements of length changes of a material for temperatures 1.4 K ⩽ T ⩽ 300 K and hydrostatic pressure P ⩽ 250 MPa. Helium (4He) is used as a pressure-transmitting medium, ensuring hydrostatic-pressure conditions. Special emphasis has been given to guarantee, to a good approximation, constant-pressure conditions during temperature sweeps. The performance of the dilatometer is demonstrated by measurements of the coefficient of thermal expansion at pressures P ≃ 0.1 MPa (ambient pressure) and 104 MPa on a single crystal of azurite, Cu3(CO3)2(OH)2, a quasi-one-dimensional spin S = 1/2 Heisenberg antiferromagnet. The results indicate a strong effect of pressure on the magnetic interactions in this system.

  4. A study on the pressure distribution in the centrifugal compressor channel diffuser at design and off-design conditions

    International Nuclear Information System (INIS)

    Kang, Jeong Seek; Kang, Shin Hyoung

    2000-01-01

    The aim of this paper is to understand the time averaged pressure distributions in a high-speed centrifugal compressor channel diffuser at design and off-design flow rates. Pressure distributions from the impeller exit to the channel diffuser exit are measured and discussed for various flow rates from choke to near surge condition, and the effect of operating condition is discussed. The strong non-uniformity in the pressure distribution is obtained over the vaneless space and semi-vaneless space caused by the impeller-diffuser interaction. As the flow rate increases, flow separation near the throat, due to large incidence angle at the vane leading edge, increases aerodynamic blockage and reduces the aerodynamic flow area downstream. Thus the minimum pressure location occurs downstream of the geometric throat, and it is named as the aerodynamic throat. And at choke condition, normal shock occurs downstream of this aerodynamic throat. The variation in the location of the aerodynamic throat is discussed

  5. High pressure argon detector of high energy neutrinos

    International Nuclear Information System (INIS)

    Vishnevskii, A.V.; Golutvin, I.A.; Sarantsev, V.L.; Sviridov, V.A.; Dolgoshein, B.A.; Kalinovskii, A.N.; Sosnovtsev, V.V.; Chernyatin, V.K.; Kaftanov, V.S.; Khovanskii, V.D.; Shevchenko, V.G.

    1979-01-01

    In the present paper, we suggest an electron neutrino detector of a new type where track information is available for all charged particles. As a working medium we use Argon compressed up to a pressure of 100 to 150 atm (approximately 0.2-0.3 g/cm 3 ). The spatial reconstruction of tracks are accomplished with an accuracy not inferior to that of bubble chambers. The detector has a high sensitivity in ionization measurements. An assembly with a working medium mass of approximately 100 tons seem to be realisable. This makes it possible to perform tasks with cross-sections of (10 -5 + 10 -3 ) x delty tot at an intensity of the neutrino beam which is available in present-day accelerators. (orig.)

  6. Pressurized water reactor iodine spiking behavior under power transient conditions

    International Nuclear Information System (INIS)

    Ho, J.C.

    1992-01-01

    The most accepted theory explaining the cause of pressurized water reactor iodine spiking is steam formation and condensation in damaged fuel rods. The phase transformation of the primary coolant from water to steam and back again is believed to cause the iodine spiking phenomenon. But due to the complex nature of the phenomenon, a comprehensive model of the behavior has not yet been successfully developed. This paper presents a new model based on an empirical approach, which gives a first-order estimation of the peak iodine spiking magnitude. Based on the proposed iodine spiking model, it is apparent that it is feasible to derive a correlation using the plant operating data base to monitor and control the peak iodine spiking magnitude

  7. Hydrogen oxidation at high pressure and intermediate temperatures: experiments and kinetic modeling

    DEFF Research Database (Denmark)

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

    2015-01-01

    was varied from very oxidizing to strongly reducing conditions. The results supplement high-pressure data from RCM (900–1100 K) and shock tubes (900–2200 K). At the reducing conditions ( U = 12), oxidation started at 748–775 K while it was shifted to 798–823 K for stoichiometric and oxidizing conditions ( U...

  8. Non-adiabatic pressure loss boundary condition for modelling turbocharger turbine pulsating flow

    International Nuclear Information System (INIS)

    Chiong, M.S.; Rajoo, S.; Romagnoli, A.; Costall, A.W.; Martinez-Botas, R.F.

    2015-01-01

    Highlights: • Bespoke non-adiabatic pressure loss boundary for pulse flow turbine modelling. • Predictions show convincing results against experimental and literature data. • Predicted pulse pressure propagation is in good agreement with literature data. • New methodology is time efficient and requires minimal geometrical inputs. - Abstract: This paper presents a simplified methodology of pulse flow turbine modelling, as an alternative over the meanline integrated methodology outlined in previous work, in order to make its application to engine cycle simulation codes much more straight forward. This is enabled through the development of a bespoke non-adiabatic pressure loss boundary to represent the turbine rotor. In this paper, turbocharger turbine pulse flow performance predictions are presented along with a comparison of computation duration against the previously established integrated meanline method. Plots of prediction deviation indicate that the mass flow rate and actual power predictions from both methods are highly comparable and are reasonably close to experimental data. However, the new boundary condition required significantly lower computational time and rotor geometrical inputs. In addition, the pressure wave propagation in this simplified unsteady turbine model at different pulse frequencies has also been found to be in agreement with data from the literature, thereby supporting the confidence in its ability to simulate the wave action encountered in turbine pulse flow operation

  9. Effects of Abrupt Variations of Solar Wind Dynamic Pressure on the High-Latitude Ionosphere

    Directory of Open Access Journals (Sweden)

    Igino Coco

    2011-01-01

    Full Text Available We show the results of a statistical study on the effects in the high-latitude ionosphere of abrupt variations of solar wind dynamic pressure, using Super Dual Auroral Radar Network (SuperDARN data in both hemispheres. We find that, during periods of quiet ionospheric conditions, the amount of radar backscatter increases when a variation in the dynamic pressure occurs, both positive (increase of the pressure and negative (decrease of the pressure. We also investigate the behaviour of the Cross-Polar Cap Potential (CPCP during pressure variations and show preliminary results.

  10. 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.

  11. Sulphation of oil shale ash under atmospheric and pressurized combustion conditions

    International Nuclear Information System (INIS)

    Kuelaots, I.; Yrjas, P.; Hupa, M.; Ots, A.

    1995-01-01

    One of the main problems in conventional combustion boilers firing pulverized oil shale is the corrosion and fouling of heating surfaces, which is caused by sulphur compounds. Another major problem, from the environmental point of view, are the high SO 2 emissions. Consequently, the amount of sulphur in flue gases must be reduced. One alternative to lower the SO 2 , concentration is the use of new technologies, such as pressurized fluidized bed combustion (PFBC). In FBC processes, the sulphur components are usually removed by the addition of limestone (CaCO 3 ) or dolomite (CaCO 3 x MgCO 3 ) into the bed. The calcium in these absorbents react with SO 2 , producing solid CaSO 4 . However, when burning oil shale, there would be no need to add limestone or dolomite into the bed, due to the initially high limestone content in the fuel (molar ratio Ca/S =10). The capture of sulphur by oil shale ashes has been studied using a pressurized thermogravimetric apparatus (PTGA). The chosen experimental conditions were typical for atmospheric and pressurized fluidized bed combustion. Four different materials were tested - one cyclone ash from an Estonian oil shale boiler, two size fractions of Estonian oil shale and, one fraction of Israeli oil shale. The cyclone ash was found to be the poorest sulphur absorbent. In general, the results from the sulphur capture experiments under both atmospheric and pressurized fluidized bed conditions showed that the oil shale can capture not only its own sulphur but also significant amounts of additional sulphur from another fuel if the fuels are mixed together. (author)

  12. Blood pressure in childhood : epidemiological probes into the aetiology of high blood pressure

    NARCIS (Netherlands)

    A. Hofman (Albert)

    1983-01-01

    textabstractHigh arterial blood pressure takes a heavy toll in western populations (1 ). Its causes are still largely unknown, but its sequelae, a variety of cardiovascular and renal diseases, have been referred to as "a modern scourge" (2). High blood pressure of unknown cause, or

  13. 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

  14. High pressure behaviour of uranium mono pnictides

    International Nuclear Information System (INIS)

    Pagare, Gitanjali; Ojha, Poonam; Sanyal, S.P.; Aynyas, Mahendra

    2006-01-01

    The pressure induced structural phase transition of three actinide mono pnictides AX (A=U and X=As, Sb, Bi), have been studied theoretically using two body interionic potential with necessary modifications to include the effect of Coulomb screening by the delocalized 5f electrons of the actinide (uranium) ion. The peculiar properties of these compounds have been interpreted in terms of the hybridization of f electrons with the conduction band. The calculated compression curves are compared with the experimental results. These compounds exhibits first order crystallographic phase transition from their NaCl (B 1 ) phase to CsCl (B 2 ) phase at 17GPa, 9.5GPa and 5.3 GPa respectively. The NaCl phase possesses lower energy than CsCl phase and stable at ambient pressure. (author)

  15. Experimental Investigation of Separated and Transitional Boundary Layers Under Low-Pressure Turbine Airfoil Conditions

    Science.gov (United States)

    Hultgren, Lennart S.; Volino, Ralph J.

    2002-01-01

    Modern low-pressure turbine airfoils are subject to increasingly stronger pressure gradients as designers impose higher loading in an effort to improve efficiency and to reduce part count. The adverse pressure gradients on the suction side of these airfoils can lead to boundary-layer separation, particularly under cruise conditions. Separation bubbles, notably those which fail to reattach, can result in a significant degradation of engine efficiency. Accurate prediction of separation and reattachment is hence crucial to improved turbine design. This requires an improved understanding of the transition flow physics. Transition may begin before or after separation, depending on the Reynolds number and other flow conditions, has a strong influence on subsequent reattachment, and may even eliminate separation. Further complicating the problem are the high free-stream turbulence levels in a real engine environment, the strong pressure gradients along the airfoils, the curvature of the airfoils, and the unsteadiness associated with wake passing from upstream stages. Because of the complicated flow situation, transition in these devices can take many paths that can coexist, vary in importance, and possibly also interact, at different locations and instances in time. The present work was carried out in an attempt to systematically sort out some of these issues. Detailed velocity measurements were made along a flat plate subject to the same nominal dimensionless pressure gradient as the suction side of a modern low-pressure turbine airfoil ('Pak-B'). The Reynolds number based on wetted plate length and nominal exit velocity, Re, was varied from 50;000 to 300; 000, covering cruise to takeoff conditions. Low, 0.2%, and high, 7%, inlet free-stream turbulence intensities were set using passive grids. These turbulence levels correspond to about 0.2% and 2.5% turbulence intensity in the test section when normalized with the exit velocity. The Reynolds number and free

  16. Structural phase transitions in Zn(CN)2 under high pressures

    International Nuclear Information System (INIS)

    Poswal, H.K.; Tyagi, A.K.; Lausi, Andrea; Deb, S.K.; Sharma, Surinder M.

    2009-01-01

    High pressure behavior of zinc cyanide (Zn(CN) 2 ) has been investigated with the help of synchrotron-based X-ray diffraction measurements. Our studies reveal that under pressure this compound undergoes phase transformations and the structures of the new phases depend on whether the pressure is hydrostatic or not. Under hydrostatic conditions, Zn(CN) 2 transforms from cubic to orthorhombic to cubic-II to amorphous phases. In contrast, the non-hydrostatic pressure conditions drive the ambient cubic phase to a partially disordered crystalline phase, which eventually evolves to a substantially disordered phase. The final disordered phase in the latter case is distinct from the amorphous phase observed under the hydrostatic pressures. - Graphical abstract: High pressure X-ray diffraction investigations on Zn(CN) 2 show three phase transformations i.e., cubic→orthorhombic→cubic-II→amorphous. However, the results strongly depend upon the nature of stress

  17. 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...

  18. Designing high pressure containers for research- principles and applications

    International Nuclear Information System (INIS)

    Anandkumar, V.

    1997-01-01

    The high pressure scientist looks for a well engineered pressure apparatus for high pressure experiments for 1 kbar (0.1 GPa) and above. Often, a variety of difficulties including the choice of materials, design configuration, optimum utilisation of the strength of materials used in the design, are encountered. This article is intended to help the high pressure scientist to select the design approach for pressure retaining container. The limitations imposed by the strength of available materials and engineering standards in building high pressure containers are discussed. Engineering solutions to overcome these limitations with optimal utilisation of the strength of the materials are also discussed. Novel methods to boost up the pressure retaining capacity like multilayered design and autofrettaging are compared along with their relative advantages and disadvantages. Special methods by which it is possible to attain pressures which are several times the yield strength of the materials of construction are presented. In this aspects such as the basis of the codes and their relevance in the design of high pressure equipment will also be described. Discussions are centered around the methods to tackle situations where experimental constraints dictate requirements of pressures higher than those permitted by design codes. Safety features are also discussed. (author)

  19. Diesel Combustion and Emission Using High Boost and High Injection Pressure in a Single Cylinder Engine

    Science.gov (United States)

    Aoyagi, Yuzo; Kunishima, Eiji; Asaumi, Yasuo; Aihara, Yoshiaki; Odaka, Matsuo; Goto, Yuichi

    Heavy-duty diesel engines have adopted numerous technologies for clean emissions and low fuel consumption. Some are direct fuel injection combined with high injection pressure and adequate in-cylinder air motion, turbo-intercooler systems, and strong steel pistons. Using these technologies, diesel engines have achieved an extremely low CO2 emission as a prime mover. However, heavy-duty diesel engines with even lower NOx and PM emission levels are anticipated. This study achieved high-boost and lean diesel combustion using a single cylinder engine that provides good engine performance and clean exhaust emission. The experiment was done under conditions of intake air quantity up to five times that of a naturally aspirated (NA) engine and 200MPa injection pressure. The adopted pressure booster is an external supercharger that can control intake air temperature. In this engine, the maximum cylinder pressure was increased and new technologies were adopted, including a monotherm piston for endurance of Pmax =30MPa. Moreover, every engine part is newly designed. As the boost pressure increases, the rate of heat release resembles the injection rate and becomes sharper. The combustion and brake thermal efficiency are improved. This high boost and lean diesel combustion creates little smoke; ISCO and ISTHC without the ISNOx increase. It also yields good thermal efficiency.

  20. 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.

  1. Pressurizer pump reliability analysis high flux isotope reactor

    International Nuclear Information System (INIS)

    Merryman, L.; Christie, B.

    1993-01-01

    During a prolonged outage from November 1986 to May 1990, numerous changes were made at the High Flux Isotope Reactor (HFIR). Some of these changes involved the pressurizer pumps. An analysis was performed to calculate the impact of these changes on the pressurizer system availability. The analysis showed that the availability of the pressurizer system dropped from essentially 100% to approximately 96%. The primary reason for the decrease in availability comes because off-site power grid disturbances sometimes result in a reactor trip with the present pressurizer pump configuration. Changes are being made to the present pressurizer pump configuration to regain some of the lost availability

  2. Pressure retarded osmosis for energy production: membrane materials and operating conditions.

    Science.gov (United States)

    Kim, H; Choi, J-S; Lee, S

    2012-01-01

    Pressure retarded osmosis (PRO) is a novel membrane process to produce energy. PRO has the potential to convert the osmotic pressure difference between fresh water (i.e. river water) and seawater to electricity. Moreover, it can recover energy from highly concentrated brine in seawater desalination. Nevertheless, relatively little research has been undertaken for fundamental understanding of the PRO process. In this study, the characteristics of the PRO process were examined using a proof-of-concept device. Forward osmosis (FO), reverse osmosis (RO), and nanofiltration (NF) membranes were compared in terms of flux rate and concentration polarization ratio. The results indicated that the theoretical energy production by PRO depends on the membrane type as well as operating conditions (i.e. back pressure). The FO membrane had the highest energy efficiency while the NF membrane had the lowest efficiency. However, the energy production rate was low due to high internal concentration polarization (ICP) in the PRO membrane. This finding suggests that the control of the ICP is essential for practical application of PRO for energy production.

  3. Racial and gender discrimination: risk factors for high blood pressure?

    Science.gov (United States)

    Krieger, N

    1990-01-01

    Despite controversy as to the biologic and/or social meaning of 'race' and 'sex', few public health studies have directly examined the impact of racial or gender discrimination on health. One plausible condition they might affect is hypertension, since stress and internalized anger may constitute important risk factors for this disease. The present investigation therefore sought to determine the feasibility of asking questions pertaining to race- and gender-biased treatment plus response to unfair treatment, and to assess their predictive value regarding self-reported high blood pressure. Using random-digit dialing, 51 black and 50 white women, ages 20-80, who resided in Alameda County, CA in 1987, were identified and interviewed by phone. Among black respondents, those who stated they usually accepted and kept quiet about unfair treatment were 4.4 times more likely to report hypertension than women who said they took action and talked to others (P = 0.01 for linear trend); no clear association existed among white respondents. The age-adjusted risk of high blood pressure among black respondents who recounted experiencing zero instances of race- and gender-biased treatment was 2.6 times greater than that of black women who reported one or more such instances (95% CI = 0.7, 10.5). Among white respondents, gender discrimination was not associated with hypertension. These results suggest that an internalized response to unfair treatment, plus non-reporting of race and gender discrimination, may constitute risk factors for high blood pressure among black women. They also bolster the view that subjective appraisal of stressors may be inversely associated with risk of hypertension.

  4. A reactor for high-throughput high-pressure nuclear magnetic resonance spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Beach, N. J.; Knapp, S. M. M.; Landis, C. R., E-mail: landis@chem.wisc.edu [Department of Chemistry, University of Wisconsin-Madison, Madison, Wisconsin 53719 (United States)

    2015-10-15

    The design of a reactor for operando nuclear magnetic resonance (NMR) monitoring of high-pressure gas-liquid reactions is described. The Wisconsin High Pressure NMR Reactor (WiHP-NMRR) design comprises four modules: a sapphire NMR tube with titanium tube holder rated for pressures as high as 1000 psig (68 atm) and temperatures ranging from −90 to 90 °C, a gas circulation system that maintains equilibrium concentrations of dissolved gases during gas-consuming or gas-releasing reactions, a liquid injection apparatus that is capable of adding measured amounts of solutions to the reactor under high pressure conditions, and a rapid wash system that enables the reactor to be cleaned without removal from the NMR instrument. The WiHP-NMRR is compatible with commercial 10 mm NMR probes. Reactions performed in the WiHP-NMRR yield high quality, information-rich, and multinuclear NMR data over the entire reaction time course with rapid experimental turnaround.

  5. 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...

  6. High-Performance Pressure Sensor for Monitoring Mechanical Vibration and Air Pressure

    Directory of Open Access Journals (Sweden)

    Yancheng Meng

    2018-05-01

    Full Text Available To realize the practical applications of flexible pressure sensors, the high performance (sensitivity and response time as well as more functionalities are highly desired. In this work, we fabricated a piezoresistive pressure sensor based on the micro-structured composites films of multi-walled carbon nanotubes (MWCNTs and poly (dimethylsiloxane (PDMS. In addition, we establish efficient strategies to improve key performance of our pressure sensor. Its sensitivity is improved up to 474.13 kPa−1 by minimizing pressure independent resistance of sensor, and response time is shorten as small as 2 μs by enhancing the elastic modulus of polymer elastomer. Benefiting from the high performance, the functionalities of sensors are successfully extended to the accurate detection of high frequency mechanical vibration (~300 Hz and large range of air pressure (6–101 kPa, both of which are not achieved before.

  7. What You Should Know About High Blood Pressure and Medications

    Science.gov (United States)

    ... Aortic Aneurysm More What You Should Know About High Blood Pressure and Medications Updated:Jan 18,2017 Is medication ... resources . This content was last reviewed October 2016. High Blood Pressure • Home • Get the Facts About HBP • Know Your ...

  8. How Potassium Can Help Control High Blood Pressure

    Science.gov (United States)

    ... Aneurysm More How Potassium Can Help Control High Blood Pressure Updated:Jan 29,2018 Understanding the heart-healthy ... This content was last reviewed October 2016. High Blood Pressure • Home • Get the Facts About HBP • Know Your ...

  9. How High Blood Pressure Can Lead to Stroke

    Science.gov (United States)

    ... Disease Venous Thromboembolism Aortic Aneurysm More How High Blood Pressure Can Lead to Stroke Updated:Jan 29,2018 ... This content was last reviewed October 2016. High Blood Pressure • Home • Get the Facts About HBP • Know Your ...

  10. High Blood Pressure and Cold Remedies: Which Are Safe?

    Science.gov (United States)

    ... counter cold remedies safe for people who have high blood pressure? Answers from Sheldon G. Sheps, M.D. Over- ... remedies aren't off-limits if you have high blood pressure, but it's important to make careful choices. Among ...

  11. High pressure discharges in cavities formed by microfabrication techniques

    International Nuclear Information System (INIS)

    Khan, B.A.; Cammack, D.A.; Pinker, R.D.; Racz, J.

    1997-01-01

    High pressure discharges are the basis of small high intensity light sources. In this work, we demonstrate the formation of high pressure discharges, in cavities formed by applying micromachining and integrated circuit techniques to quartz substrates. Cavities containing varying amounts of mercury and argon were fabricated to obtain high pressure discharges. A high pressure mercury discharge was formed in the electrodeless cavities by exciting them with a microwave source, operating at 2.45 GHz and in the electroded cavities by applying a dc voltage. The contraction of the discharge into a high pressure arc was observed. A broad emission spectrum due to self-absorption and collisions between excited atoms and normal atoms, typical of high pressure mercury discharges, was measured. The light output and efficacy increased with increasing pressure. The measured voltage was used to estimate the pressure within the electroded cavities, which is as high as 127 atm for one of the two cavities discussed in this work. Efficacies over 40 lumens per watt were obtained for the electrodeless cavities and over 50 scr(l)m/W for the electroded cavities. copyright 1997 American Institute of Physics

  12. The α → ω Transformation in Titanium-Cobalt Alloys under High-Pressure Torsion

    Directory of Open Access Journals (Sweden)

    Askar R. Kilmametov

    2017-12-01

    Full Text Available The pressure influence on the α → ω transformation in Ti–Co alloys has been studied during high pressure torsion (HPT. The α → ω allotropic transformation takes place at high pressures in titanium, zirconium and hafnium as well as in their alloys. The transition pressure, the ability of high pressure ω-phase to retain after pressure release, and the pressure interval where α and ω phases coexist depend on the conditions of high-pressure treatment. During HPT in Bridgeman anvils, the high pressure is combined with shear strain. The presence of shear strain as well as Co addition to Ti decreases the onset of the α → ω transition from 10.5 GPa (under quasi-hydrostatic conditions to about 3.5 GPa. The portion of ω-phase after HPT at 7 GPa increases in the following sequence: pure Ti → Ti–2 wt % Co → Ti–4 wt % Co → Ti–4 wt % Fe.

  13. 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.

  14. High pressure study of a highly energetic nitrogen-rich carbon nitride, cyanuric triazide

    Energy Technology Data Exchange (ETDEWEB)

    Laniel, Dominique; Desgreniers, Serge [Laboratoire de physique des solides denses, University of Ottawa, Ottawa, Ontario K1N 6N5 (Canada); Downie, Laura E. [Department of Physics and Atmospheric Science, Dalhousie University, Halifax, Nova Scotia B3H 4R2 (Canada); Smith, Jesse S. [High Pressure Collaborative Access Team, Carnegie Institution of Washington, Argonne, Illinois 60439 (United States); Savard, Didier; Murugesu, Muralee [Department of Chemistry, University of Ottawa, Ottawa, Ontario K1N 6N5 (Canada)

    2014-12-21

    Cyanuric triazide (CTA), a nitrogen-rich energetic material, was compressed in a diamond anvil cell up to 63.2 GPa. Samples were characterized by x-ray diffraction, Raman, and infrared spectroscopy. A phase transition occurring between 29.8 and 30.7 GPa was found by all three techniques. The bulk modulus and its pressure derivative of the low pressure phase were determined by fitting the 300 K isothermal compression data to the Birch-Murnaghan equation of state. Due to the strong photosensitivity of CTA, synchrotron generated x-rays and visible laser radiation both lead to the progressive conversion of CTA into a two dimensional amorphous C=N network, starting from 9.2 GPa. As a result of the conversion, increasingly weak and broad x-ray diffraction lines were recorded from crystalline CTA as a function of pressure. Hence, a definite structure could not be obtained for the high pressure phase of CTA. Results from infrared spectroscopy carried out to 40.5 GPa suggest the high pressure formation of a lattice built of tri-tetrazole molecular units. The decompression study showed stability of the high pressure phase down to 13.9 GPa. Finally, two CTA samples, one loaded with neon and the other with nitrogen, used as pressure transmitting media, were laser-heated to approximately 1100 K and 1500 K while compressed at 37.7 GPa and 42.0 GPa, respectively. In both cases CTA decomposed resulting in amorphous compounds, as recovered at ambient conditions.

  15. Impurity trapped excitons under high hydrostatic pressure

    Science.gov (United States)

    Grinberg, Marek

    2013-09-01

    Paper summarizes the results on pressure effect on energies of the 4fn → 4fn and 4fn-15d1 → 4fn transitions as well as influence of pressure on anomalous luminescence in Lnα+ doped oxides and fluorides. A model of impurity trapped exciton (ITE) was developed. Two types of ITE were considered. The first where a hole is localized at the Lnα+ ion (creation of Ln(α+1)+) and an electron is attracted by Coulomb potential at Rydberg-like states and the second where an electron captured at the Lnα+ ion (creation of Ln(α-1)+) and a hole is attracted by Coulomb potential at Rydberg-like states. Paper presents detailed analysis of nonlinear changes of energy of anomalous luminescence of BaxSr1-xF2:Eu2+ (x > 0.3) and LiBaF3:Eu2+, and relate them to ITE-4f65d1 states mixing.

  16. A study on the critical heat flux for annuli and round tubes under low pressure conditions

    International Nuclear Information System (INIS)

    Park, Jae Wook

    1997-02-01

    This study aims to reveal the characteristics of the critical heat flux (CHF) of internally heated concentric annuli and vertical round tubes in low-pressure and low-flow (LPLF) conditions. Although many efforts have been devote to the subject of the CHF during the last forty years, the information on the CHF phenomenon for LPLF conditions is still very limited. The applicable ranges of the CHF correlations for annuli and round tubes are concentrate on the operating conditions of nuclear power plant (NPP), namely high-pressure and high-flow (HPHF) conditions. these facts promoted to collect the reliable CHF data for LPLF conditions for both annuli and round tubes. The critical heat flux data for vertical flow boiling of water in annuli and round tubes at low pressures and low mass fluxes show the following trends: The observed CHF mechanism for annuli was changed in the order of flooding, churn-to-annular flow transition, and local dryout under a large bubble in churn flow as the flow rate was increased from zero to higher values. The observed parametric trends for annuli are consistent with the previous understanding except that the CHF for downward flow is considerably lower (up to 40%) than that for upward flow. The critical quality is much lower than that for round tubes at the same inlet conditions. The observed parametric trends for round tubes are generally consistent with the previous understanding except for system pressure an tube diameter effect. For the system pressure effect, it is observed that the pressure effect is complicated but not so large, whereas the existing CHF correlations do not present the parametric trend exactly. For tube diameter effect, the decreasing trends of CHF with respect to tube diameter was the general understanding so far, but in this region the CHF show a increasing trend of tube diameter. The prediction and the parametric trend analyses are performed by two view points, I.e., for fixed inlet conditions and for local

  17. 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.

  18. 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.

  19. Cable condition monitoring in a pressurized water reactor environment

    International Nuclear Information System (INIS)

    Al-Hussaini, T.J.

    1988-01-01

    Oconee Nuclear Station is the first nuclear plant designed, engineered and constructed by Duke Power Company. Even though the accelerated aging method was available to determine the life expectancy of the cable used in the reactor building, no natural aging data was available at that time. In order to be able to verify the condition of the reactor building cable over the life of the plant, an on-going cable monitoring plan was instituted. Various types of cable were selected to be monitored, and they were installed in cable life evaluation circuits in the reactor building. At five year intervals over the life of the plant, cable samples would be removed from these cable life evaluation circuits and tested to determine the effects of the reactor building environment on the integrity of the cable. A review of the cable life evaluation circuits and the results of the evaluation program to date is presented

  20. Transient pressure measurements at part load operating condition of ...

    Indian Academy of Sciences (India)

    Rahul Goyal

    2 Water Power Laboratory, Department of Energy and Process Engineering, Norwegian ... The present paper focuses on the investigation of a high head model Francis turbine operating at 50% load. ..... cascade of bandpass filters in MATLAB to eliminate the .... simulation of unsteady operation of hydroelectric systems.

  1. High blood pressure in acute ischemic stroke and clinical outcome.

    Science.gov (United States)

    Manabe, Yasuhiro; Kono, Syoichiro; Tanaka, Tomotaka; Narai, Hisashi; Omori, Nobuhiko

    2009-11-16

    This study aimed to evaluate the prognostic value of acute phase blood pressure in patients with acute ischemic stroke by determining whether or not it contributes to clinical outcome. We studied 515 consecutive patients admitted within the first 48 hours after the onset of ischemic strokes, employing systolic and diastolic blood pressure measurements recorded within 36 hours after admission. High blood pressure was defined when the mean of at least 2 blood pressure measurements was ≥200 mmHg systolic and/or ≥110 mmHg diastolic at 6 to 24 hours after admission or ≥180 mmHg systolic and/or ≥105 mmHg diastolic at 24 to 36 hours after admission. The high blood pressure group was found to include 16% of the patients. Age, sex, diabetes mellitus, hypercholesterolemia, atrial fibrillation, ischemic heart disease, stroke history, carotid artery stenosis, leukoaraiosis, NIH Stroke Scale (NIHSS) on admission and mortality were not significantly correlated with either the high blood pressure or non-high blood pressure group. High blood pressure on admission was significantly associated with a past history of hypertension, kidney disease, the modified Rankin Scale (mRS) on discharge and the length of stay. On logistic regression analysis, with no previous history of hypertension, diabetes mellitus, atrial fibrillation, and kidney disease were independent risk factors associated with the presence of high blood pressure [odds ratio (OR), 1.85 (95% confidence interval (CI): 1.06-3.22), 1.89 (95% CI: 1.11-3.22), and 3.31 (95% CI: 1.36-8.04), respectively]. Multi-organ injury may be presented in acute stroke patients with high blood pressure. Patients with high blood pressure had a poor functional outcome after acute ischemic stroke.

  2. High field conditioning of cryogenic RF cavities

    International Nuclear Information System (INIS)

    Cole, M.; Debiak, T.; Lom, C.; Shephard, W.; Sredniawski, J.

    1993-01-01

    Space-based and other related accelerators have conditioning and operation requirements that are not found in most machines. The use of cryogenic copper, relatively poor vacuum, and limited power storage and operating time put unusual demands on the high-field conditioning process and present some concerns. Two CW cryogenic engineering model open-quotes sparkerclose quotes cavities have been fabricated and tested to fairly high field levels. Tests included initial and repeated conditioning as well as sustained RF operations. The two cavities were an engineering model TDL and an engineering model RFQ. Both cavities operated at 425 MHz. The DTL was conditioned to 46 MV/m at 100% duty factor (CW) at cryogenic temperature. This corresponds to a gap voltage of 433 kV and a real estate accelerating gradient (energy gain/total cavity length) of 6.97 MV/m. The authors believe this to be record performance for cryo CW operation. During cryo pulsed operation, the same cavity reached 48 MV/m with 200 μsec pulses at 0.5% DF. The RFQ was conditioned to 30 MV/m CW at cryo, 85 kV gap voltage. During a brief period of cryo pulsed operation, the RFQ operated at 46 MV/m, or 125 kV gap voltage. Reconditioning experiments were performed on both cavities and no problems were encountered. It should be noted that the vacuum levels were not very stringent during these tests and no special cleanliness or handling procedures were followed. The results of these tests indicate that cavities can run CW without difficulty at cryogenic temperatures at normal conservative field levels. Higher field operation may well be possible, and if better vacuums are used and more attention is paid to cleanliness, much higher fields may be attainable

  3. High pressure XAFS experiments at the XAFS beamline, INDUS-2

    International Nuclear Information System (INIS)

    Ramanan, Nitya; Lahiri, Debdutta; Garg, Nandini; Sharma, Surinder M.; Bhattacharyya, D.; Jha, S.N.; Sahoo, N.K.

    2011-01-01

    The dispersive EXAFS beamline at the INDUS-2 synchrotron source, RRCAT, Indore uses a bent Si (111) crystal as a dispersive-cum-focusing element and a position sensitive CCD detector to enable instantaneous measurement of the whole EXAFS spectrum around the absorption edge of a particular atom. One of the proposed activities with this beamline is the characterization of amorphous materials under high pressure. Polychromator-based beamline is ideal for high pressure studies using Diamond Anvil Cell (DAC) with ∼ 50 μm sample size. Larger spot size would give rise to unwanted diffraction peaks from diamond, superimposed on the XAFS data. Micro-focusing by polychromator crystal and absence of its mechanical movement (unlike monochromator-based scanning-mode beamlines), during data collection, lead to required focal spot stability for DAC experiments. Currently, the theoretically determined spot size (Horizontal x vertical) varies between 17 x 137 μm and 37 x 142 μm for the X-ray energy range 5 keV-20 keV. To reduce the vertical spot size to <50 μm, we have designed an additional focusing mirror between the polychromator and sample position. The mirror, fabricated at SESO, France will be installed shortly. Meanwhile, we have carried out preliminary XAFS experiments on Sr-compounds at ∼16 keV, under ambient conditions and inside diamond anvil cell, in order to assess the signal intensity and quality. We have obtained reasonably good signal. (author)

  4. 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

  5. Radioresistance increase in polymers at high pressures. [. gamma. rays

    Energy Technology Data Exchange (ETDEWEB)

    Milinchuk, V; KIRJUKHIN, V; KLINSHPONT, E

    1977-06-01

    The effect was studied of very high pressures ranging within 100 and 2,700 MPa on the radioresistance of polytetrafluoroethylene, polypropylene and polyethylene in gamma irradiation. For experiments industrial polymers in the shape of blocks, films and fibers were used. It is shown that in easily breakable polymers, such as polytetrafluoroethylene and polypropylene, 1.3 to 2 times less free radicals are formed as a result of gamma irradiation and a pressure of 150 MPa than at normal pressure. The considerably reduced radiation-chemical formation of radicals and the destruction suppression by cross-linking in polymers is the evidence of the polymer radioresistance in irradiation at high pressures.

  6. Protection against high intravascular pressure in giraffe legs

    DEFF Research Database (Denmark)

    Petersen, Karin K; Hørlyck, Arne; Østergaard, Kristine Hovkjær

    2013-01-01

    The high blood pressure in giraffe leg arteries renders giraffes vulnerable to edema. We investigated in 11 giraffes whether large and small arteries in the legs and the tight fascia protect leg capillaries. Ultrasound imaging of foreleg arteries in anesthetized giraffes and ex vivo examination....... All three findings can contribute to protection of the capillaries in giraffe legs from a high arterial pressure....... revealed abrupt thickening of the arterial wall and a reduction of its internal diameter just below the elbow. At and distal to this narrowing, the artery constricted spontaneously and in response to norepinephrine and intravascular pressure recordings revealed a dynamic, viscous pressure drop along...

  7. Possibilities of crack mouth opening displacement (CMOD) measurement under boiling and pressurized water reactor conditions

    International Nuclear Information System (INIS)

    Ehling, W.

    1984-01-01

    Fracture mechanics investigations carried out so far in laboratory conditions cover only part of the material stresses, as effects which occur in nuclear powerstations, in particular, such as corrosion and radioactive radiation are largely left out of account. Therefore experiments including these effects were recently carried out in autoclaves, test rigs simulating reactors (HRD experimental plant) and in experimental reactors. An important parameter of experimental fracture mechanics is the measurement of crack opening displacement (COD). The crack opening is measured with socalled clip gauges (transmitters based on strain gauges, which convert mechanical deformation of springs into electrical signals) on standard samples in the laboratory. It was therefore sensible to use these high temperature strain gauges (HTD) for the development of a measuring system for travel for pressurized water and boiling water reactor conditions. (orig.) [de

  8. CARS diagnostics of high pressure discharges

    International Nuclear Information System (INIS)

    Uhlenbusch, J.

    2001-01-01

    After a short description of the principles of the CARS, RECARS and POLCARS techniques and a discussion of setups for CARS experiments some experimental results are summarized. The results concern mainly plasma under atmospheric pressure, in particular the determination of temperature in a CO 2 laser-induced pyrolysis flame burning in a silane-acetylene gas mixture, the measurements of N 2 vibrational and rotational temperatures as well as the electron density by CARS and of an NO minority by POLCARS in an atmospheric microwave discharge, and finally RECARS experiments on indium iodide, Which is present in metal halide discharge lamps. Guided by these examples some problems and difficulties arising when performing CARS measurements are discussed

  9. Development of high pressure pipe scanners

    International Nuclear Information System (INIS)

    Kim, Jae H.; Lee, Jae C.; Moon, Soon S.; Eom, Heung S.; Choi, Yu R.

    1998-12-01

    This report describes an automatic ultrasonic scanning system for pressure pipe welds, which was developed in this project using recent advanced technologies on mobile robot and computer. The system consists of two modules: a robot scanner module which navigates and manipulates scanning devices, and a data acquisition module which generates ultrasonic signal and processes the data from the scanner. The robot has 4 magnetic wheels and 2 -axis manipulator on which ultrasonic transducer attached. The wheeled robot can navigate curved surface such as outer wall of circular pipes. Magnetic wheels were optimally designed through magnetic field analysis. Free surface sensing and line tracking control algorithm were developed and implemented, and the control devices and software can be used in practical inspection works. We expect our system can contribute to reduction of inspection time, performance enhancement, and effective management of inspection results

  10. Fault gouge rheology under confined, high-velocity conditions

    Science.gov (United States)

    Reches, Z.; Madden, A. S.; Chen, X.

    2012-12-01

    We recently developed the experimental capability to investigate the shear properties of fine-grain gouge under confined conditions and high-velocity. The experimental system includes a rotary apparatus that can apply large displacements of tens of meters, slip velocity of 0.001- 2.0 m/s, and normal stress of 35 MPa (Reches and Lockner, 2010). The key new component is a Confined ROtary Cell (CROC) that can shear a gouge layer either dry or under pore-pressure. The pore pressure is controlled by two syringe pumps. CROC includes a ring-shape gouge chamber of 62.5 mm inner diameter, 81.25 mm outer diameter, and up to 3 mm thick gouge sample. The lower, rotating part of CROC contains the sample chamber, and the upper, stationary part includes the loading, hollow cylinder and setting for temperature, and dilation measurements, and pore-pressure control. Each side of the gouge chamber has two pairs of industrial, spring-energized, self-lubricating, teflon-graphite seals, built for particle media and can work at temperature up to 250 ded C. The space between each of the two sets of seals is pressurized by nitrogen. This design generates 'zero-differential pressure' on the inner seal (which is in contact with the gouge powder), and prevents gouge leaks. For the preliminary dry experiments, we used ~2.0 mm thick layers of room-dry kaolinite powder. Total displacements were on the order of meters and normal stress up to 4 MPa. The initial shear was accommodated by multiple internal slip surfaces within the kaolinite layer accommodated as oriented Riedel shear structures. Later, the shear was localized within a thin, plate-parallel Y-surface. The kaolinite layer was compacted at a quasi-asymptotic rate, and displayed a steady-state friction coefficient of ~ 0.5 with no clear dependence on slip velocity up to 0.15 m/s. Further experiments with loose quartz sand (grain size ~ 125 micron) included both dry runs and pore-pressure (distilled water) controlled runs. The sand was

  11. Deformation behavior of large, high-pressure vessel flanges

    International Nuclear Information System (INIS)

    Spaas, H.A.C.M.; Latzko, D.G.H.

    1975-01-01

    The analysis of the deformation behavior of large high-pressure vessel flanges poses a much more difficult problem than for low-pressure flanges due to their particular geometry. For a particularly narrow flange geometry (typical of PWR flanges) a finite-element analysis (MARC-IBM-program, eight-node, isoparametric ring elements) was used to predict the behavior of the flange rings. The nonlinear elastic problem resulting from the local closing and/or opening of the partial gap between the gasket faces was solved by an incremental technique using gap elements. The resulting deformation behavior of the flange system has been compared to that obtained from an analysis using the refined rigid ring concept for both bolt-tightening and hydro-testing conditions. The elasto-plastic analysis was solved by the same finite element program system as mentioned above. The incremental steps describing the nonlinear material behavior are allowed to be larger than those for the gap-closure mechanism. Besides a comparison with the former elastic analyses an interpretation will be given of the local plasticity effects, which result in a shift in location of the gasket reaction. Experimental data on local gasket face deformation was obtained by a specially developed laser beam apparatus, with the leak detection channel of the flange serving as a beam hole. Additionally strain gauges were used on flanges and bolts, in combination with special sensing pins for the determination of relative flange rotations. Results obtained so far indicate that for high-pressure flanges of the narrow design investigated here the deformation behavior is best described by an elasto-plastic finite element analysis

  12. Various high precision measurements of pressure in atomic energy industry

    International Nuclear Information System (INIS)

    Aritomi, Masanori; Inoue, Akira; Hosoma, Takashi; Tanaka, Izumi; Gabane, Tsunemichi.

    1987-01-01

    As for the pressure measurement in atomic energy industry, it is mostly the measurement using differential pressure transmitters and pressure transmitters for process measurement with the general accuracy of measurement of 0.2 - 0.5 % FS/year. However, recently for the development of nuclear fusion reactors and the establishment of nuclear fuel cycle accompanying new atomic energy technology, there are the needs of the pressure measurement having higher accuracy of 0.01 % FS/year and high resolution, and quartz vibration type pressure sensors appeared. New high accuracy pressure measurement techniques were developed by the advance of data processing and the rationalization of data transmission. As the results, the measurement of the differential pressure of helium-lithium two-phase flow in the cooling system of nuclear fusion reactors, the high accuracy measuring system for the level of plutonium nitrate and other fuel substance in tanks in fuel reprocessing and conversion, the high accuracy measurement of atmospheric pressure and wind velocity in ducts, chimneys and tunnels in nuclear facilities and so on became feasible. The principle and the measured data of quartz vibration type pressure sensors are shown. (Kako, I.)

  13. High-pressure applications in medicine and pharmacology

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Jerson L; Foguel, Debora; Suarez, Marisa; Gomes, Andre M O; Oliveira, Andrea C [Centro Nacional de Ressonancia Magnetica Nuclear, Departamento de Bioquimica Medica, Instituto de Ciencias Biomedicas, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ 21941-590 (Brazil)

    2004-04-14

    High pressure has emerged as an important tool to tackle several problems in medicine and biotechnology. Misfolded proteins, aggregates and amyloids have been studied, which point toward the understanding of the protein misfolding diseases. High hydrostatic pressure (HHP) has also been used to dissociate non-amyloid aggregates and inclusion bodies. The diverse range of diseases that result from protein misfolding has made this theme an important research focus for pharmaceutical and biotech companies. The use of high pressure promises to contribute to identifying the mechanisms behind these defects and creating therapies against these diseases. High pressure has also been used to study viruses and other infectious agents for the purpose of sterilization and in the development of vaccines. Using pressure, we have detected the presence of a ribonucleoprotein intermediate, where the coat protein is partially unfolded but bound to RNA. These intermediates are potential targets for antiviral compounds. The ability of pressure to inactivate viruses, prions and bacteria has been evaluated with a view toward the applications of vaccine development and virus sterilization. Recent studies demonstrate that pressure causes virus inactivation while preserving the immunogenic properties. There is increasing evidence that a high-pressure cycle traps a virus in the 'fusion intermediate state', not infectious but highly immunogenic.

  14. High-pressure applications in medicine and pharmacology

    International Nuclear Information System (INIS)

    Silva, Jerson L; Foguel, Debora; Suarez, Marisa; Gomes, Andre M O; Oliveira, Andrea C

    2004-01-01

    High pressure has emerged as an important tool to tackle several problems in medicine and biotechnology. Misfolded proteins, aggregates and amyloids have been studied, which point toward the understanding of the protein misfolding diseases. High hydrostatic pressure (HHP) has also been used to dissociate non-amyloid aggregates and inclusion bodies. The diverse range of diseases that result from protein misfolding has made this theme an important research focus for pharmaceutical and biotech companies. The use of high pressure promises to contribute to identifying the mechanisms behind these defects and creating therapies against these diseases. High pressure has also been used to study viruses and other infectious agents for the purpose of sterilization and in the development of vaccines. Using pressure, we have detected the presence of a ribonucleoprotein intermediate, where the coat protein is partially unfolded but bound to RNA. These intermediates are potential targets for antiviral compounds. The ability of pressure to inactivate viruses, prions and bacteria has been evaluated with a view toward the applications of vaccine development and virus sterilization. Recent studies demonstrate that pressure causes virus inactivation while preserving the immunogenic properties. There is increasing evidence that a high-pressure cycle traps a virus in the 'fusion intermediate state', not infectious but highly immunogenic

  15. Effect of High-Pressure Treatment on Catalytic and Physicochemical Properties of Pepsin.

    Science.gov (United States)

    Wang, Jianan; Bai, Tenghui; Ma, Yaping; Ma, Hanjun

    2017-10-11

    For a long time, high-pressure treatment has been used to destroy the compact structures of natural proteins in order to promote subsequent enzymatic hydrolysis. However, there are few reports evaluating the feasibility of directly improving the catalytic capability of proteases by using high-pressure treatments. In this study, the effects of high-pressure treatment on the catalytic capacity and structure of pepsin were investigated, and the relationship between its catalytic properties and changes in its physicochemical properties was explored. It was found that high-pressure treatment could lead to changes of the sulfhydryl group/disulfide bond content, hydrophobicity, hydrodynamic radius, intrinsic viscosity, and subunit composition of pepsin, and the conformational change of pepsin resulted in improvement to its enzymatic activity and hydrolysis efficiency, which had an obvious relationship with the high-pressure treatment conditions.

  16. 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)

  17. High pressure Moessbauer spectroscopy of perovskite iron oxide

    CERN Document Server

    Nasu, S; Morimoto, S; Kawakami, T; Kuzushita, K; Takano, M

    2003-01-01

    High-pressure sup 5 sup 7 Fe Moessbauer spectroscopy using a diamond anvil cell has been performed for perovskite iron oxides SrFeO sub 3 , CaFeO sub 3 and La sub 1 sub / sub 3 Sr sub 2 sub / sub 3 O sub 3. The charge states and the magnetic dependency to pressure were determined. Pressure magnetic phase diagrams of these perovskite iron oxides are determined up to about 70 GPa. To be clear the magnetic ordered state, they are measured up to 7.8 T external magnetic fields at 4.5K. The phase transition of these perovskite oxides to ferromagnetisms with high magnetic ordered temperature is observed. In higher pressure, high spin-low spin transition of oxides besides CaFeO sub 3 is generated. The feature of Moessbauer spectroscopy, perovskite iron oxide and Moessbauer spectroscopy under high pressure are explained. (S.Y.)

  18. High pressure processing reaches the U.S. market

    International Nuclear Information System (INIS)

    Mermelstein, N.H.

    1997-01-01

    The first food product commercially produced by a U.S. company using high-pressure processing has had successful test market results. High-pressure processing permits food to be preserved by subjecting it to pressures in the range of 60,000-100,000 psi for a short time instead of exposing the food to heat, freezing, chemicals, or irradiation. To produce Classic Guacamole, Avomex of Keller, Texas, uses a batch isostatic press to deactivate the enzymes in the avocado and to kill bacteria, obtaining a refrigerated shelf life of over 30 days. The guacamole is then vacuum packed and processed again. The product undergoes no heat treatment and does not contain preservatives, and the high pressure does not affect its texture, color, or taste. Meanwhile, a continuous system for high-pressure processing of pumpable foods is currently being developed by Flow International of Kent, Washington, and will be used for testing and applications work at Oregon State University

  19. High pressure orthorhombic structure of CuInSe2

    International Nuclear Information System (INIS)

    Bovornratanaraks, T; Saengsuwan, V; Yoodee, K; McMahon, M I; Hejny, C; Ruffolo, D

    2010-01-01

    The structural behaviour of CuInSe 2 under high pressure has been studied up to 53 GPa using angle-dispersive x-ray powder diffraction techniques. The previously reported structural phase transition from its ambient pressure tetragonal structure to a high pressure phase with a NaCl-like cubic structure at 7.6 GPa has been confirmed. On further compression, another structural phase transition is observed at 39 GPa. A full structural study of this high pressure phase has been carried out and the high pressure structure has been identified as orthorhombic with space group Cmcm and lattice parameters a = 4.867(8) A, b = 5.023(8) A and c = 4.980(3) A at 53.2(2) GPa. This phase transition behaviour is similar to those of analogous binary and trinary semiconductors, where the orthorhombic Cmcm structure can also be viewed as a distortion of the cubic NaCl-type structure.

  20. High pressure Moessbauer spectroscopy of perovskite iron oxide

    International Nuclear Information System (INIS)

    Nasu, Saburo; Suenaga, Tomoya; Morimoto, Shotaro; Kawakami, Takateru; Kuzushita, Kaori; Takano, Mikio

    2003-01-01

    High-pressure 57 Fe Moessbauer spectroscopy using a diamond anvil cell has been performed for perovskite iron oxides SrFeO 3 , CaFeO 3 and La 1/3 Sr 2/3 O 3 . The charge states and the magnetic dependency to pressure were determined. Pressure magnetic phase diagrams of these perovskite iron oxides are determined up to about 70 GPa. To be clear the magnetic ordered state, they are measured up to 7.8 T external magnetic fields at 4.5K. The phase transition of these perovskite oxides to ferromagnetisms with high magnetic ordered temperature is observed. In higher pressure, high spin-low spin transition of oxides besides CaFeO 3 is generated. The feature of Moessbauer spectroscopy, perovskite iron oxide and Moessbauer spectroscopy under high pressure are explained. (S.Y.)

  1. Fluorinert as a pressure-transmitting medium for high-pressure diffraction studies

    International Nuclear Information System (INIS)

    Varga, Tamas; Wilkinson, Angus P.; Angel, Ross J.

    2003-01-01

    Fluorinert is a liquid pressure-transmitting medium that is widely used in high-pressure diffraction work. A systematic study of five different fluorinerts was carried out using single-crystal x-ray diffraction in a diamond-anvil cell in order to determine the pressure range over which they provide a hydrostatic stress state to the sample. It was found that none of the fluorinerts studied can be considered hydrostatic above 1.2 GPa, a lower pressure than reported previously

  2. The effect of high pressure on nitrogen compounds of milk

    International Nuclear Information System (INIS)

    Kielczewska, Katarzyna; Czerniewicz, Maria; Michalak, Joanna; Brandt, Waldemar

    2004-01-01

    The effect of pressurization at different pressures (from 200 to 1000 MPa, at 200 MPa intervals, t const. = 15 min) and periods of time (from 15 to 35 min, at 10 min intervals, p const. = 800 MPa) on the changes of proteins and nitrogen compounds of skimmed milk was studied. The pressurization caused an increase in the amount of soluble casein and denaturation of whey proteins. The level of nonprotein nitrogen compounds and proteoso-peptone nitrogen compounds increased as a result of the high-pressure treatment. These changes increased with an increase in pressure and exposure time. High-pressure treatment considerably affected the changes in the conformation of milk proteins, which was reflected in the changes in the content of proteins sedimenting and an increase in their degree of hydration

  3. Synthesis and properties of selenium trihydride at high pressures

    Science.gov (United States)

    Zhang, Xiao; Xu, Wan; Wang, Yu; Jiang, Shuqing; Gorelli, Federico A.; Greenberg, Eran; Prakapenka, Vitali B.; Goncharov, Alexander F.

    2018-02-01

    The chemical reaction products of molecular hydrogen (H2) with selenium (Se) are studied by synchrotron x-ray diffraction (XRD) and Raman spectroscopy at high pressures. We find that a common H2Se is synthesized at 0.3 GPa using laser heating. Upon compression at 300 K, a crystal of the theoretically predicted Cccm H3Se has been grown at 4.6 GPa. At room temperature, H3Se shows a reversible phase decomposition after laser irradiation above 8.6 GPa, but remains stable up to 21 GPa. However, at 170 K Cccm H3Se persists up to 39.5 GPa based on XRD measurements, while low-temperature Raman spectra weaken and broaden above 23.1 GPa. At these conditions, the sample is visually nontransparent and shiny suggesting that metallization occurred.

  4. Low Power and High Sensitivity MOSFET-Based Pressure Sensor

    International Nuclear Information System (INIS)

    Zhang Zhao-Hua; Ren Tian-Ling; Zhang Yan-Hong; Han Rui-Rui; Liu Li-Tian

    2012-01-01

    Based on the metal-oxide-semiconductor field effect transistor (MOSFET) stress sensitive phenomenon, a low power MOSFET pressure sensor is proposed. Compared with the traditional piezoresistive pressure sensor, the present pressure sensor displays high performances on sensitivity and power consumption. The sensitivity of the MOSFET sensor is raised by 87%, meanwhile the power consumption is decreased by 20%. (cross-disciplinary physics and related areas of science and technology)

  5. 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)

  6. A study on the manufacturing conditions of metal matrix composites by low pressure infiltration process

    Energy Technology Data Exchange (ETDEWEB)

    Park, Won Jo; Hessian, Md Anowar; Park, Sung Ho [Gyeongsang National University, Tongyoung (Korea, Republic of); Huh, Sun Chul [Gyeongsang National University, JinJu (Korea, Republic of)

    2007-10-15

    Metal fiber preform reinforced aluminum alloy composite as made by the infiltration of molten metal under low pressure casting process. The infiltration behavior of filling pattern and the velocity profile with low-pressure casting process was investigated. The thermocouple was inserted into the preform in order to observe the infiltration behavior. The infiltration of applied pressure time, 1, 2 and 5 s under constant pressure of 0.4 MPa was completely filled during 0.4 s. In these conditions, molten aluminum alloy has successfully infiltrated to FeCrSi metal fiber preform by low-pressure casting process. It was observed the porosity of composites for reliability of composites. The automobile piston was developed with FeCrSi reinforced aluminum alloy that is 0% porosity by the optimal applied pressure and applied pressure time.

  7. High Blood Pressure in Adolescents of Curitiba: Prevalence and Associated Factors.

    Science.gov (United States)

    Bozza, Rodrigo; Campos, Wagner de; Barbosa Filho, Valter Cordeiro; Stabelini Neto, Antonio; Silva, Michael Pereira da; Maziero, Renato Silva Barbosa

    2016-05-01

    Arterial hypertension is a major public health problem and has increased considerably in young individuals in past years. Thus, identifying factors associated with this condition is important to guide intervention strategies in this population. To determine high blood pressure prevalence and its associated factors in adolescents. A random sample of 1,242 students enrolled in public schools of the city of Curitiba (PR) was selected. Self-administered questionnaires provided family history of hypertension, daily energy expenditure, smoking habit, daily fat intake, and socioeconomic status. Waist circumference was measured following standardized procedures, and blood pressure was measured with appropriate cuffs in 2 consecutive days to confirm high blood pressure. Relative frequency and confidence interval (95%CI) indicated high blood pressure prevalence. Bivariate and multivariate analyses assessed the association of risk factors with high blood pressure. The high blood pressure prevalence was 18.2% (95%CI 15.2-21.6). Individuals whose both parents had hypertension [odds ratio (OR), 2.22; 95%CI 1.28-3.85] and those with high waist circumference (OR, 2.1; 95%CI 1.34-3.28) had higher chances to develop high blood pressure. Positive family history of hypertension and high waist circumference were associated with high blood pressure in adolescents. These factors are important to guide future interventions in this population.

  8. High Blood Pressure in Adolescents of Curitiba: Prevalence and Associated Factors

    Directory of Open Access Journals (Sweden)

    Rodrigo Bozza

    2016-01-01

    Full Text Available Abstract Background: Arterial hypertension is a major public health problem and has increased considerably in young individuals in past years. Thus, identifying factors associated with this condition is important to guide intervention strategies in this population. Objective: To determine high blood pressure prevalence and its associated factors in adolescents. Methods: A random sample of 1,242 students enrolled in public schools of the city of Curitiba (PR was selected. Self-administered questionnaires provided family history of hypertension, daily energy expenditure, smoking habit, daily fat intake, and socioeconomic status. Waist circumference was measured following standardized procedures, and blood pressure was measured with appropriate cuffs in 2 consecutive days to confirm high blood pressure. Relative frequency and confidence interval (95%CI indicated high blood pressure prevalence. Bivariate and multivariate analyses assessed the association of risk factors with high blood pressure. Results: The high blood pressure prevalence was 18.2% (95%CI 15.2-21.6. Individuals whose both parents had hypertension [odds ratio (OR, 2.22; 95%CI 1.28-3.85] and those with high waist circumference (OR, 2.1; 95%CI 1.34-3.28 had higher chances to develop high blood pressure. Conclusion: Positive family history of hypertension and high waist circumference were associated with high blood pressure in adolescents. These factors are important to guide future interventions in this population.

  9. 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

  10. Experimental and theoretical studies on the high pressure vessel

    International Nuclear Information System (INIS)

    So, Dong Sup

    1992-02-01

    A High Pressure Melt Ejection (HPME) is one of the most important phenomena relevant to Direct Containment Heating(DCH) which could lead to an early containment failure in a several accident of PWRs. Dispersal of core debris following a postulated high pressure failure of PWR reactor vessel has been investigated by experimental works and one-dimensional computer modeling to find the relation between the fraction of melt simulant retained in the cavity and the reactor vessel initial conditions as well as to examine the hydrodynamic processes in a reactor cavity geometry. Simulated HPME experiments have been performed with two small-scale (1/25-th and 1/41-st) transparent reactor cavity models of the Young-Gwang unit 1 and 2. Wood's metal and water have been used as melt sumulants while high pressure nitrogen and carbon dioxide have been used as driver gases to simulate the blowdown steam and gas from the breach of the reactor pressure vessel. The high speed movies of the transient tests showed that no fraction of the melt simulant exits the cavity model via the vertical cavity tunnel under its own momentum, and that the discharged simulant from the pressure vessel exits the reactor cavity model during the gas blowdown. The principal removal mechanism seemed to be a combined mechanism of film entrainment and particle levitation due to the driving force of the blowdown gas. Experimental data for the fraction of melt simulant retained in the cavity model (Y f ) during a postulated scenario of the HPME from PWR pressure vessels have been obtained as a function of various test parameters. These data have been used to develop a correlation for Y f that fits all the data (a total of 313 data points) within the standard deviation of 0.054 by means of dimensional analysis and nonlinear least squares optimization technique. The basic effects of important parameters used to describe the HPME accident sequence on the Y f are determined based on the correlation obtained here and

  11. 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.

  12. Seed storage at elevated partial pressure of oxygen, a fast method for analysing seed ageing under dry conditions

    Science.gov (United States)

    Groot, S. P. C.; Surki, A. A.; de Vos, R. C. H.; Kodde, J.

    2012-01-01

    Background and Aims Despite differences in physiology between dry and relative moist seeds, seed ageing tests most often use a temperature and seed moisture level that are higher than during dry storage used in commercial practice and gene banks. This study aimed to test whether seed ageing under dry conditions can be accelerated by storing under high-pressure oxygen. Methods Dry barley (Hordeum vulgare), cabbage (Brassica oleracea), lettuce (Lactuca sativa) and soybean (Glycine max) seeds were stored between 2 and 7 weeks in steel tanks under 18 MPa partial pressure of oxygen. Storage under high-pressure nitrogen gas or under ambient air pressure served as controls. The method was compared with storage at 45 °C after equilibration at 85 % relative humidity and long-term storage at the laboratory bench. Germination behaviour, seedling morphology and tocopherol levels were assessed. Key Results The ageing of the dry seeds was indeed accelerated by storing under high-pressure oxygen. The morphological ageing symptoms of the stored seeds resembled those observed after ageing under long-term dry storage conditions. Barley appeared more tolerant of this storage treatment compared with lettuce and soybean. Less-mature harvested cabbage seeds were more sensitive, as was the case for primed compared with non-primed lettuce seeds. Under high-pressure oxygen storage the tocopherol levels of dry seeds decreased, in a linear way with the decline in seed germination, but remained unchanged in seeds deteriorated during storage at 45 °C after equilibration at 85 % RH. Conclusions Seed storage under high-pressure oxygen offers a novel and relatively fast method to study the physiology and biochemistry of seed ageing at different seed moisture levels and temperatures, including those that are representative of the dry storage conditions as used in gene banks and commercial practice. PMID:22967856

  13. Seed storage at elevated partial pressure of oxygen, a fast method for analysing seed ageing under dry conditions.

    Science.gov (United States)

    Groot, S P C; Surki, A A; de Vos, R C H; Kodde, J

    2012-11-01

    Despite differences in physiology between dry and relative moist seeds, seed ageing tests most often use a temperature and seed moisture level that are higher than during dry storage used in commercial practice and gene banks. This study aimed to test whether seed ageing under dry conditions can be accelerated by storing under high-pressure oxygen. methods: Dry barley (Hordeum vulgare), cabbage (Brassica oleracea), lettuce (Lactuca sativa) and soybean (Glycine max) seeds were stored between 2 and 7 weeks in steel tanks under 18 MPa partial pressure of oxygen. Storage under high-pressure nitrogen gas or under ambient air pressure served as controls. The method was compared with storage at 45 °C after equilibration at 85 % relative humidity and long-term storage at the laboratory bench. Germination behaviour, seedling morphology and tocopherol levels were assessed. The ageing of the dry seeds was indeed accelerated by storing under high-pressure oxygen. The morphological ageing symptoms of the stored seeds resembled those observed after ageing under long-term dry storage conditions. Barley appeared more tolerant of this storage treatment compared with lettuce and soybean. Less-mature harvested cabbage seeds were more sensitive, as was the case for primed compared with non-primed lettuce seeds. Under high-pressure oxygen storage the tocopherol levels of dry seeds decreased, in a linear way with the decline in seed germination, but remained unchanged in seeds deteriorated during storage at 45 °C after equilibration at 85 % RH. Seed storage under high-pressure oxygen offers a novel and relatively fast method to study the physiology and biochemistry of seed ageing at different seed moisture levels and temperatures, including those that are representative of the dry storage conditions as used in gene banks and commercial practice.

  14. A study on the stem friction coefficient with differential pressure conditions for the motor operated flexible wedge gate valve

    International Nuclear Information System (INIS)

    Kim, Dae Woong; Park, Sung Keun; Kim, Yang Seok; Lee, Do Hwan

    2008-01-01

    Stem friction coefficient is very important parameter for the evaluation of valve performance. In this study, the characteristics of stem friction coefficient is analyzed, and the bounding value is determined. The hydraulic testing is performed for flexible wedge gate valves in the plant and statistical method is applied to the determination of bounding value. According to the results of this study, stem friction coefficient is not effected in low differential pressure condition, but it is showed different distribution in medium and high differential pressure condition. And the bounding value of closing stroke is higher than that of opening stroke

  15. 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)

  16. High-pressure resistivity technique for quasi-hydrostatic compression experiments.

    Science.gov (United States)

    Rotundu, C R; Ćuk, T; Greene, R L; Shen, Z-X; Hemley, Russell J; Struzhkin, V V

    2013-06-01

    Diamond anvil cell techniques are now well established and powerful methods for measuring materials properties to very high pressure. However, high pressure resistivity measurements are challenging because the electrical contacts attached to the sample have to survive to extreme stress conditions. Until recently, experiments in a diamond anvil cell were mostly limited to non-hydrostatic or quasi-hydrostatic pressure media other than inert gases. We present here a solution to the problem by using focused ion beam ultrathin lithography for a diamond anvil cell loaded with inert gas (Ne) and show typical resistivity data. These ultrathin leads are deposited on the culet of the diamond and are attaching the sample to the anvil mechanically, therefore allowing for measurements in hydrostatic or nearly hydrostatic conditions of pressure using noble gases like Ne or He as pressure transmitting media.

  17. Individual Pressure Vessel (PV) and Common Pressure Vessel (CPV) Nickel-Hydrogen Battery Performance Under LEO Cycling Conditions

    Science.gov (United States)

    Miller, Thomas B.; Lewis, Harlan L.

    2004-01-01

    LEO life cycle testing of Individual Pressure Vessel (PV) and Common Pressure Vessel (CPV) nickel-hydrogen cell packs have been sponsored by the NASA Aerospace Flight Battery Program. The cell packs have cycled under both 35% and 60% depth-of- discharge and temperature conditions of -5 C and +lO C. The packs have been on test since as early as 1992 and have generated a substantial database. This report will provide insight into performance trends as a function of the specific cell configuration and manufacturer for eight separate nickel-hydrogen battery cell packs.

  18. Mechanically recovered poultry meat sausages manufactured with high hydrostatic pressure.

    Science.gov (United States)

    Yuste, J; Mor-Mur, M; Capellas, M; Guamis, B; Pla, R

    1999-06-01

    The effect of high pressure processing at high temperature on texture and color of frankfurter-type sausages made with different contents of mechanically recovered poultry meat (MRPM) was evaluated and compared with that of a standard cooking process. Five types of sausages containing 100, 75, 50, 25, and 0% MRPM and 0, 25, 50, 75, and 100% of minced pork meat (MPM), respectively, were manufactured. They were pressurized at 500 MPa for 30 min at 50, 60, 70, and 75 C or cooked at 75 C for 30 min. Pressure-treated sausages were less springy and firm, but more cohesive. Moreover, color of pressurized sausages was lighter and more yellow than that of conventionally cooked sausages. Addition of MPM increased cohesiveness, hardness, and force at 80% compression. Minced pork meat also caused the appearance of sausages to be lighter, less red, and less yellow. Cooked sausages made with MRPM can have an attractive appearance and texture via high pressure processing.

  19. Germination of vegetable seeds exposed to very high pressure

    Science.gov (United States)

    Mori, Y.; Yokota, S.; Ono, F.

    2012-07-01

    Effects of high hydrostatic pressure were investigated on vegetable seeds in the GPa range to examine the potentialities of breed improvement by high-pressure processing. Specimens of several seeds of broccoli (Brassica oleracea var. italica), Turnip leaf (Brassica rapa var. perviridis) and Potherb Mustard (Brassica rapa var. nipposinica) were put in a teflon capsule with liquid high pressure medium, fluorinate, and inserted into a pyrophillite cube. By using a cubic anvil press a hydrostatic pressure of 5.5 GP a was applied to these seeds for 15 minutes. After being brought back to ambient pressure, they were seeded on humid soil in a plant pot. Many of these vegetable seeds began to germinate within 6 days after seeded.

  20. Germination of vegetable seeds exposed to very high pressure

    International Nuclear Information System (INIS)

    Mori, Y; Yokota, S; Ono, F

    2012-01-01

    Effects of high hydrostatic pressure were investigated on vegetable seeds in the GPa range to examine the potentialities of breed improvement by high-pressure processing. Specimens of several seeds of broccoli (Brassica oleracea var. italica), Turnip leaf (Brassica rapa var. perviridis) and Potherb Mustard (Brassica rapa var. nipposinica) were put in a teflon capsule with liquid high pressure medium, fluorinate, and inserted into a pyrophillite cube. By using a cubic anvil press a hydrostatic pressure of 5.5 GP a was applied to these seeds for 15 minutes. After being brought back to ambient pressure, they were seeded on humid soil in a plant pot. Many of these vegetable seeds began to germinate within 6 days after seeded.

  1. HIGH HYDROSTATIC PRESSURE SYSTEMS USE IN FOOD INDUSTRY

    OpenAIRE

    Yahya TÜLEK; Gökçe FİLİZAY

    2006-01-01

    Food preservation is a continuous fight against microorganisms spoiling the food or making it unsafe. The last decade, non-thermal inactivation techniques have been a major research issue, driven by an increased consumer demand for nutritious, fresh like food products with a high organoleptical quality and an acceptable shelf life. Investigated inactivation technologies are ionisation radiation, high hydrostatic pressure (HHP), pulsed electrical fields, high pressure homogenisation, UV decont...

  2. Glassy selenium at high pressure: Le Chatelier's principle still works

    Science.gov (United States)

    Brazhkin, V. V.; Tsiok, O. B.

    2017-10-01

    Selenium is the only easily vitrified elementary substance. Numerous experimental studies of glassy Se (g -Se) at high pressures show a large spread in the data on the compressibility and electrical resistivity of g -Se. Furthermore, H. Liu et al. [Proc. Natl. Acad. Sci. USA 105, 13229 (2008), 10.1073/pnas.0806857105] have arrived at the surprising conclusion that the volume of glass increases during pressure-induced crystallization. We have performed high-precision measurements of the specific volume and electrical resistivity of glassy selenium (g -Se) at high hydrostatic pressures up to 9 GPa. The measured bulk modulus at normal pressure is B =(9.0 5 ±0.15 ) GPa and its pressure derivative is BP'=6.4 ±0.2 . In the pressure range P <3 GPa, glassy selenium has an anomalously large negative second derivative of the bulk modulus. The electrical resistivity of g -Se decreases almost exponentially with increasing pressure and reaches 20 Ω cm at a pressure of 8.75 GPa. The inelastic behavior and weak relaxation of the volume for g -Se begin at pressures above 3.5 GPa; the volume and logarithm of the electrical resistivity relax significantly (logarithmically with the time) at pressures above 8 GPa. Bulk measurements certainly indicate that the volume of g -Se glass in the crystallization pressure range is larger than the volumes of both appearing crystalline phases (by 2% and 4%). Therefore, the "volume expansion phenomenon" suggested in [H. Liu et al., Proc. Natl. Acad. Sci. USA 105, 13229 (2008), 10.1073/pnas.0806857105] is not observed, and the pressure-induced crystallization of glassy selenium is consistent with the laws of thermodynamics.

  3. Low Cost, High Efficiency, High Pressure Hydrogen Storage

    Energy Technology Data Exchange (ETDEWEB)

    Mark Leavitt

    2010-03-31

    A technical and design evaluation was carried out to meet DOE hydrogen fuel targets for 2010. These targets consisted of a system gravimetric capacity of 2.0 kWh/kg, a system volumetric capacity of 1.5 kWh/L and a system cost of $4/kWh. In compressed hydrogen storage systems, the vast majority of the weight and volume is associated with the hydrogen storage tank. In order to meet gravimetric targets for compressed hydrogen tanks, 10,000 psi carbon resin composites were used to provide the high strength required as well as low weight. For the 10,000 psi tanks, carbon fiber is the largest portion of their cost. Quantum Technologies is a tier one hydrogen system supplier for automotive companies around the world. Over the course of the program Quantum focused on development of technology to allow the compressed hydrogen storage tank to meet DOE goals. At the start of the program in 2004 Quantum was supplying systems with a specific energy of 1.1-1.6 kWh/kg, a volumetric capacity of 1.3 kWh/L and a cost of $73/kWh. Based on the inequities between DOE targets and Quantum’s then current capabilities, focus was placed first on cost reduction and second on weight reduction. Both of these were to be accomplished without reduction of the fuel system’s performance or reliability. Three distinct areas were investigated; optimization of composite structures, development of “smart tanks” that could monitor health of tank thus allowing for lower design safety factor, and the development of “Cool Fuel” technology to allow higher density gas to be stored, thus allowing smaller/lower pressure tanks that would hold the required fuel supply. The second phase of the project deals with three additional distinct tasks focusing on composite structure optimization, liner optimization, and metal.

  4. High hydrostatic pressure extraction of phenolic compounds from ...

    African Journals Online (AJOL)

    High hydrostatic pressure processing (HHPP) is a food processing method, in which food is subjected to the elevated pressure which is mostly between 100 to 800 MPa. HHPP is seen not only in food engineering, but also have other application areas, such as extraction of active ingredients from natural biomaterials.

  5. Growth and high pressure studies of zirconium sulphoselenide ...

    Indian Academy of Sciences (India)

    Growth and high pressure studies of zirconium sulphoselenide single ... tance was monitored in a Bridgman opposed anvil set-up up to 8 GPa pressure to identify .... The optical band gaps of the as-grown crystals were obtained by optical ab-.

  6. Investigation of Methacrylic Acid at High Pressure Using Neutron Diffraction

    DEFF Research Database (Denmark)

    Marshall, William G.; Urquhart, Andrew; Oswald, Iain D. H.

    2015-01-01

    This article shows that pressure can be a low-intensity route to the synthesis of polymethacrylic acid. The exploration of perdeuterated methacrylic acid at high pressure using neutron diffraction reveals that methacrylic acid exhibits two polymorphic phase transformations at relatively low...

  7. High pressure phases of terbium: Possibility of a thcp phase

    International Nuclear Information System (INIS)

    Staun Olsen, J.; Steenstrup, S.; Gerward, L.

    1985-01-01

    High pressure phases of trivalent Tb studied by energy dispersive X-ray diffraction with synchrotron radiation exhibits the closed packed sequence (hcp -> Sm -> dhcp -> fcc) typical of the trivalent rare earth metals. Furthermore, a phase consistent with a triple hexagonal closed packed (thcp) structure was observed in a narrow pressure range around 30 GPa. (orig.)

  8. Safety analysis of high pressure gasous fuel container punctures

    Energy Technology Data Exchange (ETDEWEB)

    Swain, M.R. [Univ. of Miami, Coral Gables, FL (United States)

    1995-09-01

    The following report is divided into two sections. The first section describes the results of ignitability tests of high pressure hydrogen and natural gas leaks. The volume of ignitable gases formed by leaking hydrogen or natural gas were measured. Leaking high pressure hydrogen produced a cone of ignitable gases with 28{degrees} included angle. Leaking high pressure methane produced a cone of ignitable gases with 20{degrees} included angle. Ignition of hydrogen produced larger overpressures than did natural gas. The largest overpressures produced by hydrogen were the same as overpressures produced by inflating a 11 inch child`s balloon until it burst.

  9. Teaming Up Against High Blood Pressure PSA (:60)

    Centers for Disease Control (CDC) Podcasts

    2012-09-04

    Nearly one-third of American adults have high blood pressure, and more than half of them don’t have it under control. Simply seeing a doctor and taking medications isn’t enough for many people who have high blood pressure. A team-based approach by patients, health care systems, and health care providers is one of the best ways to treat uncontrolled high blood pressure.  Created: 9/4/2012 by Centers for Disease Control and Prevention (CDC).   Date Released: 9/4/2012.

  10. Safety supervision on high-pressure gas regulations

    International Nuclear Information System (INIS)

    Lee, Won Il

    1991-01-01

    The first part lists the regulation on safety supervision of high-pressure gas, enforcement ordinance on high-pressure gas safety supervision and enforcement regulations about high-pressure gas safety supervision. The second part indicates safety regulations on liquefied petroleum gas and business, enforcement ordinance of safety on liquefied petroleum gas and business, enforcement regulation of safety supervision over liquefied petroleum gas and business. The third part lists regulation on gas business, enforcement ordinance and enforcement regulations on gas business. Each part has theory and explanation for questions.

  11. Excessively High Vapor Pressure of Al-based Amorphous Alloys

    Directory of Open Access Journals (Sweden)

    Jae Im Jeong

    2015-10-01

    Full Text Available Aluminum-based amorphous alloys exhibited an abnormally high vapor pressure at their approximate glass transition temperatures. The vapor pressure was confirmed by the formation of Al nanocrystallites from condensation, which was attributed to weight loss of the amorphous alloys. The amount of weight loss varied with the amorphous alloy compositions and was inversely proportional to their glass-forming ability. The vapor pressure of the amorphous alloys around 573 K was close to the vapor pressure of crystalline Al near its melting temperature, 873 K. Our results strongly suggest the possibility of fabricating nanocrystallites or thin films by evaporation at low temperatures.

  12. 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

  13. High-pressure structural behaviour of nanocrystalline Ge

    International Nuclear Information System (INIS)

    Wang, H; Liu, J F; He, Y; Wang, Y; Chen, W; Jiang, J Z; Olsen, J Staun; Gerward, L

    2007-01-01

    The equation of state and the pressure of the I-II transition have been studied for nanocrystalline Ge using synchrotron x-ray diffraction. The bulk modulus and the transition pressure increase with decreasing particle size for both Ge-I and Ge-II, but the percentage volume collapse at the transition remains constant. Simplified models for the high-pressure structural behaviour are presented, based on the assumption that a large fraction of the atoms reside in grain boundary regions of the nanocrystalline material. The interface structure plays a significant role in affecting the transition pressure and the bulk modulus

  14. 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.

  15. 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...

  16. 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.

  17. High-pressure behavior of CaMo O4

    Science.gov (United States)

    Panchal, V.; Garg, N.; Poswal, H. K.; Errandonea, D.; Rodríguez-Hernández, P.; Muñoz, A.; Cavalli, E.

    2017-09-01

    We report a high-pressure study of tetragonal scheelite-type CaMo O4 up to 29 GPa. In order to characterize its high-pressure behavior, we have combined Raman and optical-absorption measurements with density functional theory calculations. We have found evidence of a pressure-induced phase transition near 15 GPa. Experiments and calculations agree in assigning the high-pressure phase to a monoclinic fergusonite-type structure. The reported results are consistent with previous powder x-ray-diffraction experiments, but are in contradiction with the conclusions obtained from earlier Raman measurements, which support the existence of more than one phase transition in the pressure range covered by our studies. The observed scheelite-fergusonite transition induces significant changes in the electronic band gap and phonon spectrum of CaMo O4 . We have determined the pressure evolution of the band gap for the low- and high-pressure phases as well as the frequencies and pressure dependencies of the Raman-active and infrared-active modes. In addition, based on calculations of the phonon dispersion of the scheelite phase, carried out at a pressure higher than the transition pressure, we propose a possible mechanism for the reported phase transition. Furthermore, from the calculations we determined the pressure dependence of the unit-cell parameters and atomic positions of the different phases and their room-temperature equations of state. These results are compared with previous experiments showing a very good agreement. Finally, information on bond compressibility is reported and correlated with the macroscopic compressibility of CaMo O4 . The reported results are of interest for the many technological applications of this oxide.

  18. Effect of High Pressure and Heat on Bacterial Toxins

    Directory of Open Access Journals (Sweden)

    Dirk Margosch

    2005-01-01

    Full Text Available Even though the inactivation of microorganisms by high pressure treatment is a subject of intense investigations, the effect of high pressure on bacterial toxins has not been studied so far. In this study, the influence of combined pressure/temperature treatment (0.1 to 800 MPa and 5 to 121 °C on bacterial enterotoxins was determined. Therefore, heat-stable enterotoxin (STa of cholera toxin (CT from Vibrio cholerae, staphylococcal enterotoxins A-E, haemolysin BL (HBL from Bacillus cereus, and Escherichia coli (STa were subjected to different treatment schemes. Structural alterations were monitored in enzyme immunoassays (EIAs. Cytotoxicity of the pressure treated supernatant of toxigenic B. cereus DSM 4384 was investigated with Vero cells. High pressure of 200 to 800 MPa at 5 °C leads to a slight increase of the reactivity of the STa of E. coli. However, reactivity decreased at 800 MPa and 80 °C to (66±21 % after 30 min and to (44±0.3 % after 128 min. At ambient pressure no decrease in EIA reactivity could be observed after 128 min. Pressurization (0.1 to 800 MPa of heat stable monomeric staphylococcal toxins at 5 and 20 °C showed no effect. A combined heat (80 °C and pressure (0.1 to 800 MPa treatment lead to a decrease in the immuno-reactivity to 20 % of its maximum. For cholera toxin a significant loss in latex agglutination was observable only at 80 °C and 800 MPa for holding times higher than 20 min. Interestingly, the immuno-reactivity of B. cereus HBL toxin increased with the increase of pressure (182 % at 800 MPa, 30 °C, and high pressure showed only minor effects on cytotoxicity to Vero cells. Our results indicate that pressurization can increase inactivation observed by heat treatment, and combined treatments may be effective at lower temperatures and/or shorter incubation time.

  19. Superhard MgB sub 2 bulk material prepared by high-pressure sintering

    CERN Document Server

    Ma, H A; Chen, L X; Zhu, P W; Ren, G Z; Guo, W L; Fu, X Q; Zou Guang Tian; Ren, Z A; Che, G C; Zhao, Z X

    2002-01-01

    Superhard MgB sub 2 bulk material with a golden metallic shine was synthesized by high-pressure sintering for 8 h at 5.5 GPa and different temperatures. Appropriate pressure and temperature conditions for synthesizing polycrystalline MgB sub 2 with high hardness were investigated. The samples were characterized by means of atomic force microscopy and x-ray diffraction. The Vickers hardness, bulk density, and electrical resistivity were measured at room temperature.

  20. High pressure inertial focusing for separating and concentrating bacteria at high throughput

    Science.gov (United States)

    Cruz, J.; Hooshmand Zadeh, S.; Graells, T.; Andersson, M.; Malmström, J.; Wu, Z. G.; Hjort, K.

    2017-08-01

    Inertial focusing is a promising microfluidic technology for concentration and separation of particles by size. However, there is a strong correlation of increased pressure with decreased particle size. Theory and experimental results for larger particles were used to scale down the phenomenon and find the conditions that focus 1 µm particles. High pressure experiments in robust glass chips were used to demonstrate the alignment. We show how the technique works for 1 µm spherical polystyrene particles and for Escherichia coli, not being harmful for the bacteria at 50 µl min-1. The potential to focus bacteria, simplicity of use and high throughput make this technology interesting for healthcare applications, where concentration and purification of a sample may be required as an initial step.