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Sample records for high pressure metallization

  1. The effect of high pressures on actinide metals

    International Nuclear Information System (INIS)

    Benedict, U.

    1987-01-01

    The solid state properties of the actinides are controlled by the dualism of the localized and itinerant (delocalized) configuration of the 5f electrons. This dualism allows to define two main subgroups. At ambient pressures the first subgroup, of elements with atomic number 91 to 94, is characterized by 5f electrons in an itinerant state and the second subgroup, atomic number 95 to 98, by 5f electrons in a localized state. The latter means that these electrons have well defined energy levels and do not contribute to the metallic bond. The other two subgroups consist of thorium, as a subgroup of its own because its 5f levels are practically unoccupied in the ground state configuration, and of the five heaviest elements with atomic number 99 to 103. The most remarkable effect of pressure on the actinide metals is that due to closer contact between the lattice atoms, localized 5f electrons can become itinerant, hybridise with the conduction electrons and participate in the metallic bond. In this chapter the high-pressure structural behaviour of actinide metals is reviewed. Section 3 gives an introduction into the techniques of generating and measuring pressure and of determining various physical properties of the actinides under pressure and describes a few high-pressure devices and methods. Sections 4 to 7 treat the high-pressure results for each subgroup separately. In section 8 the results of the preceding sections are brought together in a graphical representation which consists of interconnecting binary phase diagrams of neighbouring actinide metals. 155 refs.; 14 figs.; 7 tabs. (H.W.)

  2. High pressure gas driven liquid metal MHD homopolar generator

    International Nuclear Information System (INIS)

    Itoh, Yasuyuki

    1988-01-01

    A liquid metal MHD homopolar generator is proposed to be used as a high repetition rate pulsed power supply. In the generator, the thermal energy stored in a high pressure gas (He) reservoir is rapidly converted into kinetic energy of a rotating liquid metal (NaK) cylinder which is contracted by a gas driven annular free piston. The rotational kinetic energy is converted into electrical energy by making use of the homopolar generator principle. The conversion efficiency is calculated to be 47% in generating electrical energy of 20 kJ/pulse (1.7 MW peak power) at a repetition rate of 7 Hz. From the viewpoint of energy storage, the high pressure gas reservoir with a charging pressure of 15 MPa is considered to ''electrically'' store the energy at a density of 10 MJ/m 3 . (author)

  3. Superconductivity of ternary metal compounds prepared at high pressures

    CERN Document Server

    Shirotani, I

    2003-01-01

    Various ternary metal phosphides, arsenides, antimonides, silicides and germanides have been prepared at high temperatures and high pressures. These ternary metal compounds can be classified into four groups: [1] metal-rich compounds MM' sub 4 X sub 2 and [2] MM'X, [3] non-metal-rich compounds MXX' and [4] MM' sub 4 X sub 1 sub 2 (M and M' = metal element; X and X' = non-metal element). We have studied the electrical and magnetic properties of these materials at low temperatures, and found many new superconductors with the superconducting transition temperature (T sub c) of above 10 K. The metal-rich compound ZrRu sub 4 P sub 2 with a tetragonal structure showed the superconducting transition at around 11 K, and had an upper critical field (H sub c sub 2) of 12.2 tesla (T) at 0 K. Ternary equiatomic compounds ZrRuP and ZrRuSi crystallize in two modifications, a hexagonal Fe sub 2 P-type structure [h-ZrRuP(Si)] and an orthorhombic Co sub 2 P-type structure [o-ZrRuP(Si)]. Both h-ZrRuP and h-ZrRuSi have rather h...

  4. Rare-earth-metal nitridophosphates through high-pressure metathesis

    International Nuclear Information System (INIS)

    Kloss, Simon David; Schnick, Wolfgang

    2015-01-01

    Developing a synthetic method to target an broad spectrum of unknown phases can lead to fascinating discoveries. The preparation of the first rare-earth-metal nitridophosphate LiNdP_4N_8 is reported. High-pressure solid-state metathesis between LiPN_2 and NdF_3 was employed to yield a highly crystalline product. The in situ formed LiF is believed to act both as the thermodynamic driving force and as a flux to aiding single-crystal formation in dimensions suitable for crystal structure analysis. Magnetic properties stemming from Nd"3"+ ions were measured by SQUID magnetometry. LiNdP_4N_8 serves as a model system for the exploration of rare-earth-metal nitridophosphates that may even be expanded to transition metals. High-pressure metathesis enables the systematic study of these uncharted regions of nitride-based materials with unprecedented properties. (copyright 2015 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  5. Selective gettering of hydrogen in high pressure metal iodide lamps

    International Nuclear Information System (INIS)

    Kuus, G.

    1976-01-01

    One of the main problems in the manufacture of high pressure gas discharge lamps is the elimination of gaseous impurities from their arc tubes. Long degassing processes of all the lamp components are necessary in order to produce lamps with a low ignition voltage and good maintenance of the radiation properties. The investigation described deals with a selective getter place in the arc tube which can replace the long degassing process. The getter consists of a piece of yttrium encapsulated in thin tantalum foil. By this way it is possible to use the gettering action of tantalum and yttrium without having reaction between the metal iodide of the arc tube and yttrium. Yttrium is used because this metal can adsorb a large quantity of hydrogen even at a temperature of 1000 0 C. Hydrogen forms the main gaseous impurity in the high pressure metal iodide lamp. For this reason the adsorption properties like adsorption rate and capacity of the tantalum--yttrium getter for hydrogen are examined, and the results obtained from lamp experiments are given

  6. High-Pressure Thermodynamic Properties of f-electron Metals, Transition Metal Oxides, and Half-Metallic Magnets

    International Nuclear Information System (INIS)

    Richard T. Scalettar; Warren E. Pickett

    2005-01-01

    This project involves research into the thermodynamic properties of f-electron metals, transition metal oxides, and half-metallic magnets at high pressure. These materials are ones in which the changing importance of electron-electron interactions as the distance between atoms is varied can tune the system through phase transitions from localized to delocalized electrons, from screened to unscreened magnetic moments, and from normal metal to one in which only a single spin specie can conduct. Three main thrusts are being pursued: (1) Mott transitions in transition metal oxides, (2) magnetism in half-metallic compounds, and (3) large volume-collapse transitions in f-band metals

  7. High-Pressure Thermodynamic Properties of f-electron Metals, Transition Metal Oxides, and Half-Metallic Magnets

    Energy Technology Data Exchange (ETDEWEB)

    Scalettar, Richard T.; Pickett, Warren E.

    2004-07-01

    This project involves research into the thermodynamic properties of f-electron metals, transition metal oxides, and half-metallic magnets at high pressure. These materials are ones in which the changing importance of electron-electron interactions as the distance between atoms is varied can tune the system through phase transitions from localized to delocalized electrons, from screened to unscreened magnetic moments, and from normal metal to one in which only a single spin specie can conduct. Three main thrusts are being pursued: (1) Mott transitions in transition metal oxides, (2) magnetism in half-metallic compounds, and (3) large volume-collapse transitions in f-band metals.

  8. High-Pressure Thermodynamic Properties of f-electron Metals, Transition Metal Oxides, and Half-Metallic Magnets

    Energy Technology Data Exchange (ETDEWEB)

    Richard T. Scalettar; Warren E. Pickett

    2005-08-02

    This project involves research into the thermodynamic properties of f-electron metals, transition metal oxides, and half-metallic magnets at high pressure. These materials are ones in which the changing importance of electron-electron interactions as the distance between atoms is varied can tune the system through phase transitions from localized to delocalized electrons, from screened to unscreened magnetic moments, and from normal metal to one in which only a single spin specie can conduct. Three main thrusts are being pursued: (i) Mott transitions in transition metal oxides, (ii) magnetism in half-metallic compounds, and (iii) large volume-collapse transitions in f-band metals.

  9. Helium solubility and bubble growth in metals under high pressure

    International Nuclear Information System (INIS)

    Laakmann, J.

    1985-07-01

    Helium solubility and bubble growth in metals under high pressure polycrystals and single crystals of gold were heated in helium at temperatures between 475 K and 1250 K in a pressure regime of 200 to 2700 bar to measure the solubility of helium in gold. After quenching to room temperature the helium content, measured by mass spectrometry, showed the following properties: 1) A linear dependence of the He solubility on pressure. 2) Thinning of the specimen reduces the helium content by a factor 10 to 100 but does not change the linear pressure dependence. 3) The thermal release of He from thinned polycrystals and single crystals occurs mainly in a single peak at 500 K. 4) The He concentration of the thinned single crystals was lower by a factor of 10 to 50 than that of the thinned polycrystals. 5) The He solubility in single crystals can be described by an enthalpy of solution Hsub(s)sup(f) = 0.85 +- 0.7 eV and a non-configurational entropy of Ssub(s)sup(f) between 0 k and 1 k (k: Boltzmann-constant). In order to measure the pressure dependence of helium bubble growth in nickel polycrystal Ni-foils were α-implanted to a helium content of 130 appm. The evaluation of the size distribution of the helium bubbles after heat treatments shows 1) The helium content of the observable bubbles - assumed to be in equilibrium - equals the amount of helium implanted into the specimen. 2) The activation energy for the growth of helium bubbles is 1.25 +- 0.3 eV. The comparison of specimen which had been heated at low pressures up to 10 bar with others heated at 2500-2700 bar does not show an unequivocal pressure dependence for helium bubble growth. (orig./IHOE) [de

  10. High pressure die casting of Fe-based metallic glass

    Science.gov (United States)

    Ramasamy, Parthiban; Szabo, Attila; Borzel, Stefan; Eckert, Jürgen; Stoica, Mihai; Bárdos, András

    2016-01-01

    Soft ferromagnetic Fe-based bulk metallic glass key-shaped specimens with a maximum and minimum width of 25.4 and 5 mm, respectively, were successfully produced using a high pressure die casting (HPDC) method, The influence of die material, alloy temperature and flow rate on the microstructure, thermal stability and soft ferromagnetic properties has been studied. The results suggest that a steel die in which the molten metal flows at low rate and high temperature can be used to produce completely glassy samples. This can be attributed to the laminar filling of the mold and to a lower heat transfer coefficient, which avoids the skin effect in the steel mold. In addition, magnetic measurements reveal that the amorphous structure of the material is maintained throughout the key-shaped samples. Although it is difficult to control the flow and cooling rate of the molten metal in the corners of the key due to different cross sections, this can be overcome by proper tool geometry. The present results confirm that HPDC is a suitable method for the casting of Fe-based bulk glassy alloys even with complex geometries for a broad range of applications. PMID:27725780

  11. High pressure die casting of Fe-based metallic glass.

    Science.gov (United States)

    Ramasamy, Parthiban; Szabo, Attila; Borzel, Stefan; Eckert, Jürgen; Stoica, Mihai; Bárdos, András

    2016-10-11

    Soft ferromagnetic Fe-based bulk metallic glass key-shaped specimens with a maximum and minimum width of 25.4 and 5 mm, respectively, were successfully produced using a high pressure die casting (HPDC) method, The influence of die material, alloy temperature and flow rate on the microstructure, thermal stability and soft ferromagnetic properties has been studied. The results suggest that a steel die in which the molten metal flows at low rate and high temperature can be used to produce completely glassy samples. This can be attributed to the laminar filling of the mold and to a lower heat transfer coefficient, which avoids the skin effect in the steel mold. In addition, magnetic measurements reveal that the amorphous structure of the material is maintained throughout the key-shaped samples. Although it is difficult to control the flow and cooling rate of the molten metal in the corners of the key due to different cross sections, this can be overcome by proper tool geometry. The present results confirm that HPDC is a suitable method for the casting of Fe-based bulk glassy alloys even with complex geometries for a broad range of applications.

  12. High pressure die casting of Fe-based metallic glass

    Science.gov (United States)

    Ramasamy, Parthiban; Szabo, Attila; Borzel, Stefan; Eckert, Jürgen; Stoica, Mihai; Bárdos, András

    2016-10-01

    Soft ferromagnetic Fe-based bulk metallic glass key-shaped specimens with a maximum and minimum width of 25.4 and 5 mm, respectively, were successfully produced using a high pressure die casting (HPDC) method, The influence of die material, alloy temperature and flow rate on the microstructure, thermal stability and soft ferromagnetic properties has been studied. The results suggest that a steel die in which the molten metal flows at low rate and high temperature can be used to produce completely glassy samples. This can be attributed to the laminar filling of the mold and to a lower heat transfer coefficient, which avoids the skin effect in the steel mold. In addition, magnetic measurements reveal that the amorphous structure of the material is maintained throughout the key-shaped samples. Although it is difficult to control the flow and cooling rate of the molten metal in the corners of the key due to different cross sections, this can be overcome by proper tool geometry. The present results confirm that HPDC is a suitable method for the casting of Fe-based bulk glassy alloys even with complex geometries for a broad range of applications.

  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. Vacancies und melting curves of metals at high pressure

    International Nuclear Information System (INIS)

    Gorecki, T.

    1977-01-01

    The vacancy mechanism of the melting process is utilized as a starting point in derivation of the pressure dependence of melting temperature for metals. The results obtained for the initial slope of the melting curve are compared with experimental data for 45 metals (including U, Np, Pu, rare earths) and in most cases the agreement is very good. An on-linearity of the fusion curve and appearence of the maximum on the melting curve at a pressure approximately equal to the bulk modulus is also predicted with qualitative agreement with existing experimental data. (orig./GSC) [de

  15. Pressure Resistance Welding of High Temperature Metallic Materials

    International Nuclear Information System (INIS)

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

    2010-01-01

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

  16. High pressure and microwave based synthesis of transition metal pnictides

    Energy Technology Data Exchange (ETDEWEB)

    Pobel, Roman Rupert

    2016-04-11

    The goal of this thesis was to explore the possibilities of synthetic methods that are not very common in current transition metal pnictide research. The substitution of the Ca-site in CaFe{sub 2}As{sub 2} with rare earth elements such as Pr the has been reported to induce superconductivity. However, some inconsistencies in the data suggested a non-intrinsic origin of the observed diamagnetic signal. Furthermore a solubility limit of 13% was found when prepared in an electrical furnace thus leaving a huge part of the physical phase diagram inaccessible. A high pressure/high temperature synthesis was developed to allow access to the whole doping range and an in-depth characterization of this compound was carried out. During the experiments concerning the high pressure synthesis of Ca{sub 1-x}Pr{sub x}Fe{sub 2}As{sub 2} the new ternary iron arsenide CaFe{sub 5}As{sub 3} was identified and classified as a member of the Ca{sub n(n+1)/2}(Fe{sub 1-x}M{sub x}){sub (2+3n)}M'{sub n(n-1)/2}As{sub (n+1)(n+2)/2} (n = 1-3; M =Nb, Pd, Pt; M' = □, Pd, Pt) family. The complete solid solution Ca{sub 1-x}Pr{sub x}Fe{sub 5}As{sub 3} (O ≤ x ≤ 1) was prepared and physically characterized. Furthermore, several useful techniques were developed to aid in future high pressure based investigations of transition metal pnictides. The second part of this thesis concerns a completely different, but equally promising synthetic approach. Microwave based synthesis is a well-established technique in many solution based fields, such as organic, medicinal or nano chemistry. For solid state and materials research several parameters and particularities have to be considered. But when successful, it allows for the reduction of reaction time by several orders of magnitude. It has very rarely been applied in the preparation of pnictides and on1y once in the context of pnictide superconductor research. The possibilities of this method were explored and employed in the preparation of several

  17. High pressure metallization of Mott Insulators: Magnetic, structural and electronic properties

    International Nuclear Information System (INIS)

    Pasternak, M.P.; Hearne, G.; Sterer, E.; Taylor, R.D.; Jeanloz, R.

    1993-01-01

    High pressure studies of the insulator-metal transition in the (TM)I 2 (TM = V, Fe, Co and Ni) compounds are described. Those divalent transition-metal iodides are structurally isomorphous and classified as Mott Insulators. Resistivity, X-ray diffraction and Moessbauer Spectroscopy were employed to investigate the electronic, structural, and magnetic properties as a function of pressure both on the highly correlated and on the metallic regimes

  18. Metal azides under pressure: An emerging class of high energy ...

    Indian Academy of Sciences (India)

    Advanced Centre of Research in High Energy Materials (ACRHEM), University of ... behaviour of LiN3 and KN3 by means of density functional calculations. ... and 4.08 eV (KN3) and as pressure increases the band gap decreases and show ...

  19. High-pressure phase transition of alkali metal-transition metal deuteride Li2PdD2

    Science.gov (United States)

    Yao, Yansun; Stavrou, Elissaios; Goncharov, Alexander F.; Majumdar, Arnab; Wang, Hui; Prakapenka, Vitali B.; Epshteyn, Albert; Purdy, Andrew P.

    2017-06-01

    A combined theoretical and experimental study of lithium palladium deuteride (Li2PdD2) subjected to pressures up to 50 GPa reveals one structural phase transition near 10 GPa, detected by synchrotron powder x-ray diffraction, and metadynamics simulations. The ambient-pressure tetragonal phase of Li2PdD2 transforms into a monoclinic C2/m phase that is distinct from all known structures of alkali metal-transition metal hydrides/deuterides. The structure of the high-pressure phase was characterized using ab initio computational techniques and from refinement of the powder x-ray diffraction data. In the high-pressure phase, the PdD2 complexes lose molecular integrity and are fused to extended [PdD2]∞ chains. The discovered phase transition and new structure are relevant to the possible hydrogen storage application of Li2PdD2 and alkali metal-transition metal hydrides in general.

  20. Phase transformations in cerium and thorium metals at ultra high pressures

    International Nuclear Information System (INIS)

    Vohra, Y.K.

    1991-01-01

    This paper reports on the role of pressure variable in phase transformation which has not been fully exploited in metallic elements and their alloys. The static compression of over 50% in volume can readily be obtained in most metals and this tremendous change in inter-atomic distances can lead to the formation of new exotic crystal structures. The pressure-induced electron transfer amongst existing electronic energy bands and the occupation of new bands are the driving forces in a rich variety of phase transformations. The modern high pressure diamond anvil cell techniques can produce calibrated static pressures of over 300 to 400 GPa range and this technology, when interfaced with the synchrotron radiation sources, can yield rapid structural information (1-3). These capabilities have given new impetus for investigation of phase transformations in metallic systems at extreme conditions of temperatures and pressures and in establishing phase boundaries at high pressures and high temperatures. Cerium (Ce) and thorium (Th) metals occupy special positions in the periodic table at the beginning of the 4-f lanthanide and 5-f, actinide series, respectively. Ce has one electron in the localized 4-f shell, apart from the three valence electrons. Th metal, on the other hand, has four valence electrons and an unoccupied 5-f band above the Fermi-energy at ambient conditions. In view of the unoccupied 5-f band, Th metal is normally regarded as a tetravalent transition metal like Ti, Zr, and Hf and its bonding and other electronic properties can be explained within the tetravalent transition metal framework. However, the application of ultra-high pressures causes the delocalization of the 4-f shell in Ce and it is believed that Ce above 0.8 GPa pressure is a 4-f band metal

  1. Highly Sensitive, Transparent, and Durable Pressure Sensors Based on Sea-Urchin Shaped Metal Nanoparticles.

    Science.gov (United States)

    Lee, Donghwa; Lee, Hyungjin; Jeong, Youngjun; Ahn, Yumi; Nam, Geonik; Lee, Youngu

    2016-11-01

    Highly sensitive, transparent, and durable pressure sensors are fabricated using sea-urchin-shaped metal nanoparticles and insulating polyurethane elastomer. The pressure sensors exhibit outstanding sensitivity (2.46 kPa -1 ), superior optical transmittance (84.8% at 550 nm), fast response/relaxation time (30 ms), and excellent operational durability. In addition, the pressure sensors successfully detect minute movements of human muscles. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  2. Electronic structure and superconductivity of divalent metals under very high pressure

    International Nuclear Information System (INIS)

    Bireckoven, B.

    1987-05-01

    A single crystal, high-pressure diamond cell has been developed for the study of superconductors under pressures to over 50 GPa. A high sensitivity AC-SQUID magnetometer has been employed to detect the diamagnetic response of the very small samples at T C . The T C (p)-dependence of the lead-manometer has been calibrated against the ruby-pressure-scale up to pressures of 30 GPa. In spite of the well-known fcc/hcp-transition at 13 GPa lead shows a smooth T C (p)-behaviour and thus is a very suitable manometer. Band structure calculations for the alkaline earth metals indicate an appreciable s-to-d transfer with increasing pressure. In fact, superconductivity was previously observed in the pressure induced d-transition metals Sr and Ba (however not yet in Ca). For the first time the author presents a quantitative investigation of T C as a function of p up to 50 GPa. Both elements turn out to be ''good'' superconductors featuring T C 's of about 7 K. The possibility of a generalized phase diagram for the alkaline earth metals will be critically discussed. At any rate, the occurrence of such high T C 's is rather strong evidence for a substantial d-transition metal character at high p. Investigations of very dilute BaEu-alloys up to 45 GPa reveal a strong monotonic increase of ΔT C = T C Ba -T C BaEu . (orig./GSCH)

  3. Using NIF to Test Theories of High-Pressure, High-Rate Plastic Flow in Metals

    Science.gov (United States)

    Rudd, Robert E.; Arsenlis, A.; Cavallo, R. M.; Huntington, C. M.; McNaney, J. M.; Park, H. S.; Powell, P.; Prisbrey, S. T.; Remington, B. A.; Swift, D.; Wehrenberg, C. E.; Yang, L.

    2017-10-01

    Precisely controlled plasmas are playing key roles both as pump and probe in experiments to understand the strength of solid metals at high energy density (HED) conditions. In concert with theoretical advances, these experiments have enabled a predictive capability to model material strength at Mbar pressures and high strain rates. Here we describe multiscale strength models developed for tantalum starting with atomic bonding and extending up through the mobility of individual dislocations, the evolution of dislocation networks and so on until the ultimate material response at the scale of an experiment. Experiments at the National Ignition Facility (NIF) probe strength in metals ramp compressed to 1-8 Mbar. The model is able to predict 1 Mbar experiments without adjustable parameters. The combination of experiment and theory has shown that solid metals can behave significantly differently at HED conditions. We also describe recent studies of lead compressed to 3-5 Mbar. Work performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under contract DE-AC52-07NA273.

  4. Systematic prediction of high-pressure melting curves of transition metals

    International Nuclear Information System (INIS)

    Hieu, Ho Khac

    2014-01-01

    The pressure effects on melting temperatures of transition metals have been studied based on the combination of the modified Lindemann criterion with statistical moment method in quantum statistical mechanics. Numerical calculations have been performed for five transition metals including Cu, Pd, Pt, Ni, and Mn up to pressure 100 GPa. Our results are in good and reasonable agreements with available experimental data. This approach gives us a relatively simple method for qualitatively calculating high-pressure melting temperature. Moreover, it can be used to verify future experimental and theoretical works. This research proposes the potential of the combination of statistical moment method and the modified Lindemann criterion on predicting high-pressure melting of materials.

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

    International Nuclear Information System (INIS)

    Quinby, T.C.

    1980-01-01

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

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

    Science.gov (United States)

    Quinby, T.C.

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

  7. Evidence for photo-induced monoclinic metallic VO2 under high pressure

    International Nuclear Information System (INIS)

    Hsieh, Wen-Pin; Mao, Wendy L.; Trigo, Mariano; Reis, David A.; Andrea Artioli, Gianluca; Malavasi, Lorenzo

    2014-01-01

    We combine ultrafast pump-probe spectroscopy with a diamond-anvil cell to decouple the insulator-metal electronic transition from the lattice symmetry changing structural transition in the archetypal strongly correlated material vanadium dioxide. Coherent phonon spectroscopy enables tracking of the photo-excited phonon vibrational frequencies of the low temperature, monoclinic (M 1 )-insulating phase that transforms into the metallic, tetragonal rutile structured phase at high temperature or via non-thermal photo-excitations. We find that in contrast with ambient pressure experiments where strong photo-excitation promptly induces the electronic transition along with changes in the lattice symmetry, at high pressure, the coherent phonons of the monoclinic (M 1 ) phase are still clearly observed upon the photo-driven phase transition to a metallic state. These results demonstrate the possibility of synthesizing and studying transient phases under extreme conditions

  8. Evidence for photo-induced monoclinic metallic VO{sub 2} under high pressure

    Energy Technology Data Exchange (ETDEWEB)

    Hsieh, Wen-Pin, E-mail: wphsieh@stanford.edu; Mao, Wendy L. [Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, Menlo Park, California 94025 (United States); Department of Geological and Environmental Sciences, Stanford University, Stanford, California 94305 (United States); Trigo, Mariano [Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, Menlo Park, California 94025 (United States); Stanford PULSE Institute, SLAC National Accelerator Laboratory, Menlo Park, California 94025 (United States); Reis, David A. [Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, Menlo Park, California 94025 (United States); Stanford PULSE Institute, SLAC National Accelerator Laboratory, Menlo Park, California 94025 (United States); Department of Photon Science and Applied Physics, Stanford University, Stanford, California 94305 (United States); Andrea Artioli, Gianluca; Malavasi, Lorenzo [Dipartimento di Chimica, Sezione di Chimica Fisica, INSTM (UdR Pavia), Università di Pavia, Viale Taramelli 16, 27100 Pavia (Italy)

    2014-01-13

    We combine ultrafast pump-probe spectroscopy with a diamond-anvil cell to decouple the insulator-metal electronic transition from the lattice symmetry changing structural transition in the archetypal strongly correlated material vanadium dioxide. Coherent phonon spectroscopy enables tracking of the photo-excited phonon vibrational frequencies of the low temperature, monoclinic (M{sub 1})-insulating phase that transforms into the metallic, tetragonal rutile structured phase at high temperature or via non-thermal photo-excitations. We find that in contrast with ambient pressure experiments where strong photo-excitation promptly induces the electronic transition along with changes in the lattice symmetry, at high pressure, the coherent phonons of the monoclinic (M{sub 1}) phase are still clearly observed upon the photo-driven phase transition to a metallic state. These results demonstrate the possibility of synthesizing and studying transient phases under extreme conditions.

  9. Viscosity measurements on metal melts at high pressure and viscosity calculations for the earth's core

    International Nuclear Information System (INIS)

    Mineev, Vladimir N; Funtikov, Aleksandr I

    2004-01-01

    A review is given of experimental and calculated data on the viscosity of iron-based melts on the melting curve. The interest in these data originates in the division of opinion on whether viscosity increases rather moderately or considerably in the high-pressure range. This disagreement is especially pronounced in the interpretation of the values of molten iron and its compounds in the environment of the earth's outer core. The conclusion on a substantial rise in viscosity mostly follows from the universal law, proposed by Brazhkin and Lyapin [1], of viscosity changing along the metal melting curve in the high-pressure range. The review analyzes available experimental and computational data, including the most recent ones. Data on viscosity of metals under shock wave compression in the megabar pressure range are also discussed. It is shown that data on viscosity of metal melts point to a small increase of viscosity on the melting curve. Specifics are discussed of the phase diagram of iron made more complex by the presence of several phase transitions and by the uncertainty in the position of the melting curve in the high-pressure range. Inaccuracies that arise in extrapolating the results of viscosity measurements to the pressure range corresponding to the earth's core environment are pointed out. (reviews of topical problems)

  10. High-pressure metallization of FeO and implications for the earth's core

    Science.gov (United States)

    Knittle, Elise; Jeanloz, Raymond

    1986-01-01

    The phase diagram of FeO has been experimentally determined to pressures of 155 GPa and temperatures of 4000 K using shock-wave and diamond-cell techniques. A metallic phase of FeO is observed at pressures greater than 70 GPa and temperatures exceeding 1000 K. The metallization of FeO at high pressures implies that oxygen can be present as the light alloying element of the earth's outer core, in accord with the geochemical predictions of Ringwood (1977 and 1979). The high pressures necessary for this metallization suggest that the core has acquired its composition well after the initial stages of the earth's accretion. Direct experimental observations at elevated pressures and temperatures indicate that core-forming alloy can react chemically with oxides such as those forming the mantle. The core and mantle may never have reached complete chemical equilibrium, however. If this is the case, the core-mantle boundary is likely to be a zone of active chemical reactions.

  11. Electronic and structural ground state of heavy alkali metals at high pressure

    Science.gov (United States)

    Fabbris, G.; Lim, J.; Veiga, L. S. I.; Haskel, D.; Schilling, J. S.

    2015-02-01

    Alkali metals display unexpected properties at high pressure, including emergence of low-symmetry crystal structures, which appear to occur due to enhanced electronic correlations among the otherwise nearly free conduction electrons. We investigate the high-pressure electronic and structural ground state of K, Rb, and Cs using x-ray absorption spectroscopy and x-ray diffraction measurements together with a b i n i t i o theoretical calculations. The sequence of phase transitions under pressure observed at low temperature is similar in all three heavy alkalis except for the absence of the o C 84 phase in Cs. Both the experimental and theoretical results point to pressure-enhanced localization of the valence electrons characterized by pseudogap formation near the Fermi level and strong s p d hybridization. Although the crystal structures predicted to host magnetic order in K are not observed, the localization process appears to drive these alkalis closer to a strongly correlated electron state.

  12. Chemically Designed Metallic/Insulating Hybrid Nanostructures with Silver Nanocrystals for Highly Sensitive Wearable Pressure Sensors.

    Science.gov (United States)

    Kim, Haneun; Lee, Seung-Wook; Joh, Hyungmok; Seong, Mingi; Lee, Woo Seok; Kang, Min Su; Pyo, Jun Beom; Oh, Soong Ju

    2018-01-10

    With the increase in interest in wearable tactile pressure sensors for e-skin, researches to make nanostructures to achieve high sensitivity have been actively conducted. However, limitations such as complex fabrication processes using expensive equipment still exist. Herein, simple lithography-free techniques to develop pyramid-like metal/insulator hybrid nanostructures utilizing nanocrystals (NCs) are demonstrated. Ligand-exchanged and unexchanged silver NC thin films are used as metallic and insulating components, respectively. The interfaces of each NC layer are chemically engineered to create discontinuous insulating layers, i.e., spacers for improved sensitivity, and eventually to realize fully solution-processed pressure sensors. Device performance analysis with structural, chemical, and electronic characterization and conductive atomic force microscopy study reveals that hybrid nanostructure based pressure sensor shows an enhanced sensitivity of higher than 500 kPa -1 , reliability, and low power consumption with a wide range of pressure sensing. Nano-/micro-hierarchical structures are also designed by combining hybrid nanostructures with conventional microstructures, exhibiting further enhanced sensing range and achieving a record sensitivity of 2.72 × 10 4 kPa -1 . Finally, all-solution-processed pressure sensor arrays with high pixel density, capable of detecting delicate signals with high spatial selectivity much better than the human tactile threshold, are introduced.

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

    Science.gov (United States)

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

    2004-03-01

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

  14. X-ray Compton scattering experiments for fluid alkali metals at high temperatures and pressures

    Energy Technology Data Exchange (ETDEWEB)

    Matsuda, K., E-mail: kazuhiro-matsuda@scphys.kyoto-u.ac.jp; Fukumaru, T.; Kimura, K.; Yao, M. [Graduate School of Science, Kyoto University, Kyoto 606-8502 (Japan); Tamura, K. [Graduate School of Engineering, Kyoto University, Kyoto 606-8502 (Japan); Katoh, M. [A.L.M.T. Corp., Iwasekoshi-Machi 2, Toyama 931-8543 (Japan); Kajihara, Y.; Inui, M. [Graduate School of Integrated Arts and Sciences, Hiroshima University, Higashi-Hiroshima 739-8521 (Japan); Itou, M.; Sakurai, Y. [Japan Synchrotron Radiation Research Institute, SPring-8, 1-1-1 Kouto, Sayo, Hyogo 679-5198 (Japan)

    2015-08-17

    We have developed a high-pressure vessel and a cell for x-ray Compton scattering measurements of fluid alkali metals. Measurements have been successfully carried out for alkali metal rubidium at elevated temperatures and pressures using synchrotron radiation at SPring-8. The width of Compton profiles (CPs) of fluid rubidium becomes narrow with decreasing fluid density, which indicates that the CPs sensitively detect the effect of reduction in the valence electron density. At the request of all authors of the paper, and with the agreement of the Proceedings Editor, an updated version of this article was published on 10 September 2015. The original article supplied to AIP Publishing was not the final version and contained PDF conversion errors in Formulas (1) and (2). The errors have been corrected in the updated and re-published article.

  15. Optical study on metal-insulator change in PrFe4P12 under high pressure

    International Nuclear Information System (INIS)

    Irizawa, Akinori; Sato, Kazuyuki; Kobayashi, Masayo; Nanba, Takao; Matsunami, Masaharu; Sugawara, Hitoshi; Sato, Hideyuki

    2007-01-01

    The optical study has been performed on filled-skutterudite PrFe 4 P 12 applying pressure up to 16 GPa. The reflectivity at far-infrared (FIR) region showed that the metallic reflectivity looses its intensity and the weak phonon peaks at ambient pressure become prominent with pressures at lower temperature. It insists that the electronic states near Fermi level in this compound changes drastically from metallic properties to insulating ones at high pressures and low temperatures, and the insulating phase persists up to 16 GPa against the electrical resistivity data under pressure

  16. Quasi-two-dimensional metallic hydrogen in diphosphide at a high pressure

    International Nuclear Information System (INIS)

    Degtyarenko, N. N.; Mazur, E. A.

    2016-01-01

    The structural, electronic, phonon, and other characteristics of the normal phases of phosphorus hydrides with stoichiometry PH k are analyzed. The properties of the initial substance, namely, diphosphine are calculated. In contrast to phosphorus hydrides with stoichiometry PH 3 , a quasi-two-dimensional phosphorus-stabilized lattice of metallic hydrogen can be formed in this substance during hydrostatic compression at a high pressure. The formed structure with H–P–H elements is shown to be locally stable in phonon spectrum, i.e., to be metastable. The properties of diphosphine are compared with the properties of similar structures of sulfur hydrides.

  17. Quasi-two-dimensional metallic hydrogen inside di-phosphide at high pressure

    International Nuclear Information System (INIS)

    Degtyarenko, N N; Mazur, E A

    2016-01-01

    The method of mathematical modelling was used for the calculation of the structural, electronic, phononic, and other characteristics of various normal phases of phosphorus hydrides with stoichiometry PH k . It was shown that the di-phosphine may form 2D lattice of the metallic hydrogen in it, stabilized by phosphorus atoms under high hydrostatic pressure. The resulting structure with the elements of H-P-H has a locally stable (or metastable) phonon spectrum. The properties of di-phosphine were compared with the properties of similar structures such as the sulphur hydrides. (paper)

  18. Reuse of waste water from high pressure water jet decontamination for reactor decommissioning scrap metal

    International Nuclear Information System (INIS)

    Deng Junxian; Li Xin; Hou Huijuan

    2011-01-01

    For recycle and reuse of reactor decommissioning scrap metal by high pressure water jet decontamination, large quantity of radioactive waste water will be generated. To save the cost of radioactive waste water treatment and to reduce the cost of the scrap decontamination, this part of radioactive waste water should be reused. Most of the radioactivities in the decontamination waste water come from the solid particle in the water. Thus to reuse the waste water, the solid particle in the waster should be removed. Different possible treatment technologies have been investigated. By cost benefit analysis the centrifugal separation technology is selected. (authors)

  19. Quasi-two-dimensional metallic hydrogen in diphosphide at a high pressure

    Energy Technology Data Exchange (ETDEWEB)

    Degtyarenko, N. N.; Mazur, E. A., E-mail: eugen-mazur@mail.ru [National Research Nuclear University MEPhI (Russian Federation)

    2016-08-15

    The structural, electronic, phonon, and other characteristics of the normal phases of phosphorus hydrides with stoichiometry PH{sub k} are analyzed. The properties of the initial substance, namely, diphosphine are calculated. In contrast to phosphorus hydrides with stoichiometry PH{sub 3}, a quasi-two-dimensional phosphorus-stabilized lattice of metallic hydrogen can be formed in this substance during hydrostatic compression at a high pressure. The formed structure with H–P–H elements is shown to be locally stable in phonon spectrum, i.e., to be metastable. The properties of diphosphine are compared with the properties of similar structures of sulfur hydrides.

  20. High-power laser-metal interactions in pressurized gaseous atmospheres

    Energy Technology Data Exchange (ETDEWEB)

    Bitelli, G. [ENEA, Centro Ricerche Frascati, Rome (Italy). Dip. Innovazione; Lugomer, S.; Furic, K.; Ivanda, M. [Ruder Boskovic Institute, Zagreb (Croatia); Stipancic, M. [Electrotechnical faculty, Osijek (Croatia); Stubicar, M. [Faculty of natural sciences and mathematics, Zagreb (Croatia); Gamulin, O. [School of medicine, Univ. of Zagreb, Zagreb (Croatia)

    1996-09-01

    Metal surfaces were irradiated in pressurized gaseous atmospheres by a CO{sub 2} laser beam. The gaseous pressures ranged from 2 atm to 6 atm, the energy density of the light beam was about 20-50 J/cm{sup 2} with a power density {approx} 10{sup 9} W/cm{sup 2} and a pulse duration p 150 ns. In the above conditions some new effects were observed. The laser-material interaction occurred in a highly absorptive plasma regime, meaning that the metal surface was effectively screened from the beam. The interaction ended either with plasma adiabatic expansion, in the case of Mo (in O{sub 2}), Te (in N{sub 2}) and T{sub i} (in N{sub 2}), or with plasma explosion, in the case of T{sub i} (in O{sub 2}). The metal surface properties were studied by means of optical analysis, microhardness tests, X-ray diffraction and Raman backscattering.

  1. Small-Scale Metal Tanks for High Pressure Storage of Fluids

    Science.gov (United States)

    London, Adam (Inventor)

    2016-01-01

    Small scale metal tanks for high-pressure storage of fluids having tank factors of more than 5000 meters and volumes of ten cubic inches or less featuring arrays of interconnected internal chambers having at least inner walls thinner than gage limitations allow. The chambers may be arranged as multiple internal independent vessels. Walls of chambers that are also portions of external tank walls may be arcuate on the internal and/or external surfaces, including domed. The tanks may be shaped adaptively and/or conformally to an application, including, for example, having one or more flat outer walls and/or having an annular shape. The tanks may have dual-purpose inlet/outlet conduits of may have separate inlet and outlet conduits. The tanks are made by fusion bonding etched metal foil layers patterned from slices of a CAD model of the tank. The fusion bonded foil stack may be further machined.

  2. High-pressure, ambient temperature hydrogen storage in metal-organic frameworks and porous carbon

    Science.gov (United States)

    Beckner, Matthew; Dailly, Anne

    2014-03-01

    We investigated hydrogen storage in micro-porous adsorbents at ambient temperature and pressures up to 320 bar. We measured three benchmark adsorbents: two metal-organic frameworks, Cu3(1,3,5-benzenetricarboxylate)2 [Cu3(btc)2; HKUST-1] and Zn4O(1,3,5-benzenetribenzoate)2 [Zn4O(btb)2; MOF-177], and the activated carbon MSC-30. In this talk, we focus on adsorption enthalpy calculations using a single adsorption isotherm. We use the differential form of the Claussius-Clapeyron equation applied to the Dubinin-Astakhov adsorption model to calculate adsorption enthalpies. Calculation of the adsorption enthalpy in this way gives a temperature independent enthalpy of 5-7 kJ/mol at the lowest coverage for the three materials investigated. Additionally, we discuss the assumptions and corrections that must be made when calculating adsorption isotherms at high-pressure and adsorption enthalpies.

  3. Calculation of Oxygen Fugacity in High Pressure Metal-Silicate Experiments and Comparison to Standard Approaches

    Science.gov (United States)

    Righter, K.; Ghiorso, M.

    2009-01-01

    Calculation of oxygen fugacity in high pressure and temperature experiments in metal-silicate systems is usually approximated by the ratio of Fe in the metal and FeO in the silicate melt: (Delta)IW=2*log(X(sub Fe)/X(sub FeO)), where IW is the iron-wustite reference oxygen buffer. Although this is a quick and easy calculation to make, it has been applied to a huge variety of metallic (Fe- Ni-S-C-O-Si systems) and silicate liquids (SiO2, Al2O3, TiO2, FeO, MgO, CaO, Na2O, K2O systems). This approach has surely led to values that have little meaning, yet are applied with great confidence, for example, to a terrestrial mantle at "IW-2". Although fO2 can be circumvented in some cases by consideration of Fe-M distribution coefficient, these do not eliminate the effects of alloy or silicate liquid compositional variation, or the specific chemical effects of S in the silicate liquid, for example. In order to address the issue of what the actual value of fO2 is in any given experiment, we have calculated fO2 from the equilibria 2Fe (metal) + SiO2 (liq) + O2 = Fe2SiO4 (liq).

  4. Correlated structural and electronic phase transformations in transition metal chalcogenide under high pressure

    Energy Technology Data Exchange (ETDEWEB)

    Li, Chunyu, E-mail: licy@hpstar.ac.cn, E-mail: yanhao@hpstar.ac.cn; Ke, Feng; Yu, Zhenhai; Chen, Zhiqiang; Yan, Hao, E-mail: licy@hpstar.ac.cn, E-mail: yanhao@hpstar.ac.cn [Center for High Pressure Science and Technology Advanced Research, Shanghai 201203 (China); Hu, Qingyang [Center for High Pressure Science and Technology Advanced Research, Shanghai 201203 (China); Geophysical Laboratory, Carnegie Institution of Washington, Washington, DC 20015 (United States); Zhao, Jinggeng [Natural Science Research Center, Academy of Fundamental and Interdisciplinary Sciences, Harbin Institute of Technology, Harbin 150080 (China)

    2016-04-07

    Here, we report comprehensive studies on the high-pressure structural and electrical transport properties of the layered transition metal chalcogenide (Cr{sub 2}S{sub 3}) up to 36.3 GPa. A structural phase transition was observed in the rhombohedral Cr{sub 2}S{sub 3} near 16.5 GPa by the synchrotron angle dispersive X-ray diffraction measurement using a diamond anvil cell. Through in situ resistance measurement, the electric resistance value was detected to decrease by an order of three over the pressure range of 7–15 GPa coincided with the structural phase transition. Measurements on the temperature dependence of resistivity indicate that it is a semiconductor-to-metal transition in nature. The results were also confirmed by the electronic energy band calculations. Above results may shed a light on optimizing the performance of Cr{sub 2}S{sub 3} based applications under extreme conditions.

  5. Metal-insulator transition in n-InSb under high hydrostatic pressure

    International Nuclear Information System (INIS)

    Schaller, U.; Kraak, W.; Herrmann, R.

    1984-01-01

    The effect of applying hydrostatic compression (up to 12 kbar) to the galvanomagnetic properties of pure n-InSb crystals is investigated in order to get information about the influence of hydrostatic pressure on the localization of carriers and about the metal-insulator transition. Electrical resistivity and Hall coefficient are measured as a function of pressure for various excess donor concentrations as well as a function of temperature for various pressures

  6. Metal extrusion using hydrostatic pressures

    International Nuclear Information System (INIS)

    Sauve, Ch.

    1965-01-01

    The main problems connected with the deformation of metals due to extrusion are described. A method is put forward for calculating the rational rate of percentage deformation in the case of bar extrusion using a cylindrical container; reference is made to previous work on extrusion using a hydrostatic pressure with or without back-pressure. An extrusion process is described using hydrostatic pressure, without back-pressure, and using the lubricant for transmitting the thrust. This process has been used for eight years by the C.E.A. for the extrusion of a very wide range of metals, from beryllium to uranium and including steels; it leads to excellent surface textures. A very fine crystallization can be obtained on extruded products when the rate of extrusion is very low. There appears to be nothing against the use of high extrusion rates using this method. (author) [fr

  7. A High-Pressure Study of Manganese Metal and its Reactions with CO2 at 6, 23, and 44 GPa

    Science.gov (United States)

    Sawchuk, K. L. S.; McGuire, C. P.; Greenburg, A.; Makhluf, A.; Kavner, A.

    2017-12-01

    The free energies of formation of oxides and carbonates at the extreme pressures and temperatures of Earth's interior provides some of the thermodynamic constrains for models of mantle/core formation and subsequent chemical evolution. The broad goal of our research program is to measure the pressure- and temperature-dependence of free energies of formation of transition metal oxides and carbonates. This requires measurements of the phase stability, density, and thermoelastic properties of metals, oxides, and carbonates at deep-Earth and planetary conditions. Manganese is of interest because it is one of the most abundant transition metal geochemical tracers, it readily forms a carbonate at ambient pressure, and its high-pressure carbonate and oxide densities and equation of state parameters are relatively unknown. Here we report new data on the pressure/volume equation of state and structure of manganese metal as well as its reactions with CO2. These measurements were made using a laser heated diamond anvil cell in conjunction with synchrotron-based X-ray diffraction at beamline 12.2.2 at the Advanced Light Source. Three samples of manganese metal were gas-loaded in a CO2 pressure medium and pressurized to 6, 23, and 44 GPa. Upon laser heating, the CO2 reacted with the Mn metal generating new phases. To analyze the diffraction patterns, we we use a python-based program developed in-house for extracting high resolution 2-dimensional diffraction peak position and intensity information from two-dimensional X-ray diffraction patterns. At each pressure step, the structure and density of the quenched Mn metal phase was determined. At 6 GPa, Mn metal adopts a BCC structure, and at 23 GPa a tetragonal distortion is observed in the lattice. The measured equation of state is in good agreement with an existing meaurement by Fujihisa and Takemura (1995). MnCO3 rhodochrosite is observed in the sample quenched after heating at 6 GPa. Additional high pressure phases are evident

  8. Thermophysical and transport properties of metals at high pressure and very high temperature

    International Nuclear Information System (INIS)

    Shaner, J.W.; Gathers, G.R.

    1977-01-01

    Simultaneous measurements of enthalpy, specific volume, temperature, and electrical resistivity for lead and uranium were measured. From the measured data, estimates of the bulk modulus and sound velocity in these metals are made

  9. Design of hydroforming processes for metallic liners used in high pressure hydrogen storage

    International Nuclear Information System (INIS)

    Gelin, J.C.; Labergere, C.; Thibaud, S.; Boudeau, N.

    2005-01-01

    Within the framework of an European project concerning hydrogen storage, one analyze the way to manufacture high pressure tanks (700bars) for hydrogen storage, intended to be embarked for using in motor vehicles. These tanks consist of a metallic liner, which ensure a barrier role compared to the hydrogen atoms as well as a part of the mechanical resistance, and of a composite envelope built by filament rolling up which ensures the complementary part of the mechanical resistance. The paper describes the work completed within this framework, on the basis of the simulation of the hydroforming process thanks to the complete control of the process, in volume of fluid injected. One was thus brought to develop an optimization module based on finite element calculations. This optimization module includes MPI library in order to launch several calculations in parallel on a Linux cluster. It consists in seeking the optimal evolution of the fluid volume injected vs. time to obtain a good quality component. In our case, the optimization criterion is based on the variation thickness of the tube and the possible appearance of necking. It is shown that such a way for controlling the process provide the way to get minimal thickness variation, comparatively to standard optimization approaches where the process parameters are discretized through processing time in a more standard way

  10. Generalized computational model for high-pressure metal hydrides with variable thermal properties

    DEFF Research Database (Denmark)

    Mazzucco, Andrea; Rokni, Masoud

    2015-01-01

    This study considers a detailed 1D fueling model applied to a metal hydride system, with Ti1.1CrMn as the absorbing alloy, to predict the weight fraction of the absorbed hydrogen and the solid bed temperature. Dependencies of thermal conductivity and specific heat capacity upon pressure...... is estimated to be approximately 10%. Copyright (C) 2015, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved....

  11. Special features of the formation of high-conductivity phases of halides of alkali metals at superhigh pressures

    International Nuclear Information System (INIS)

    Babushkin, A.N.; Babushkina, G.V.

    1999-01-01

    The halides of alkali metals are the simplest crystals with the ionic nature of chemical bonds and are used widely as modelling materials in high-pressure physics. As a result of previous theoretical and experimental (optical, structural, electro-physical and shock-waves) investigations it was shown that these materials may be characterised by the overlapping of the valency and conduction bands and by the formation of groups of free charge carriers at pressures of the megabaric level. However, the authors know of no data on the direct investigations of the electrophysical properties of the halides of alkali metals at such high static pressures. The end of this investigation was to examine the temperature dependences of the electrical conductivity and thermal EMF of halides of alkali metals AX (A = Na, K, Rb, Cs, X = Cl, Br, I) in a wide temperature range at pressures from 10 to 50 GPa in order to reveal the general leisure since governing the change of their electronic structures, in particular, the transition to the state with the activation-type or metallic conductivity

  12. Thin film metal sensors in fusion bonded glass chips for high-pressure microfluidics

    International Nuclear Information System (INIS)

    Andersson, Martin; Ek, Johan; Hedman, Ludvig; Johansson, Fredrik; Sehlstedt, Viktor; Stocklassa, Jesper; Snögren, Pär; Pettersson, Victor; Larsson, Jonas; Vizuete, Olivier; Hjort, Klas; Klintberg, Lena

    2017-01-01

    High-pressure microfluidics offers fast analyses of thermodynamic parameters for compressed process solvents. However, microfluidic platforms handling highly compressible supercritical CO 2 are difficult to control, and on-chip sensing would offer added control of the devices. Therefore, there is a need to integrate sensors into highly pressure tolerant glass chips. In this paper, thin film Pt sensors were embedded in shallow etched trenches in a glass wafer that was bonded with another glass wafer having microfluidic channels. The devices having sensors integrated into the flow channels sustained pressures up to 220 bar, typical for the operation of supercritical CO 2 . No leakage from the devices could be found. Integrated temperature sensors were capable of measuring local decompression cooling effects and integrated calorimetric sensors measured flow velocities over the range 0.5–13.8 mm s −1 . By this, a better control of high-pressure microfluidic platforms has been achieved. (paper)

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

    Directory of Open Access Journals (Sweden)

    Tao Luo

    2014-09-01

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

  14. 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

  15. High temperature vapor pressures of stainless steel type 1.4970 and of some other pure metals from laser evaporation

    International Nuclear Information System (INIS)

    Bober, M.; Singer, J.

    1984-10-01

    For the safety analysis of nuclear reactors vapor pressure data of stainless steel are required up to temperatures exceeding 4000 K. In analogy to the classic boiling point method a new technique was developed to measure the high-temperature vapor pressures of stainless steel and other metals from laser vaporization. A fast pyrometer, an ion current probe and an image converter camera are used to detect incipient boiling from the time-temperature curve. The saturated-vapor pressure curves of stainless steel (Type 1.4970), being a cladding material of the SNR 300 breeder reactor, and of molybdenum are experimentally determined in the temperature ranges of 2800-3900 K and 4500-5200 K, respectively. The normal boiling points of iron, nickel, titanium, vanadium and zirconium are verified. Besides, spectral emissivity values of the liquid metals are measured at the pyrometer wavelengths of 752 nm and/or 940 nm. (orig.) [de

  16. Highly sensitive multi-layer pressure sensor with an active nanostructured layer of an organic molecular metal

    International Nuclear Information System (INIS)

    Laukhin, V; Lebedev, V; Laukhina, E; Rovira, C; Veciana, J

    2016-01-01

    This work addresses to the modern technologies that need to be instrumented with lightweight highly sensitive pressure sensors. The paper presents the development of a new plain flexible thin pressure sensor using a nanostructured layer of the highly sensitive organic piezoresistive metal β-(BEDT-TTF) 2 I 3 as an active component; BEDT-TTF=bis (ethylenedithio)tetrathiafulvalene. The original construction approach permits one to operate the developed sensor on the principle of electrical resistance variations when its piezoresistive layer is elongated under a pressure increase. The pressure sensing element and a set of gold electrodes were integrated into one compact multi-layer design. The construction was optimized to enable one generic design for pressure ranges from 1 to 400 bar. The pressure tests showed that the sensor is able to control a small pressure change as a well definite electrical signal. So the developed type of the sensors is very attractive as a new generation of compact, lightweight, low-cost sensors that might monitor pressure with a good level of measurement accuracy. (paper)

  17. 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.

  18. Metal additive manufacturing of a high-pressure micro-pump

    NARCIS (Netherlands)

    Wits, Wessel Willems; Weitkamp, Sander J.; van Es, J.; van Es, Johannes

    2013-01-01

    For the thermal control of future space applications pumped two-phase loops are an essential part to handle the increasing thermal power densities. This study investigates the design of a reliable, leak tight, low-weight and high-pressure micro-pump for small satellite applications. The developed

  19. Semi-solid high pressure die casting of metal matrix composites produced by liquid state processing

    CSIR Research Space (South Africa)

    Ivanchev, L

    2012-10-01

    Full Text Available stirring. The composite was then transferred to a High Pressure Die Casting (HPDC) machine in the semi-solid state. The micron size particles were found to be predominantly in the intergranular eutectic while the nano-particles were predominantly...

  20. Structure, Mobility, and Composition of Transition Metal Catalyst Surfaces. High-Pressure Scanning Tunneling Microscopy and Ambient-Pressure X-ray Photoelectron Spectroscopy Studies

    Energy Technology Data Exchange (ETDEWEB)

    Zhu, Zhongwei [Univ. of California, Berkeley, CA (United States)

    2013-12-06

    Surface structure, mobility, and composition of transition metal catalysts were studied by high-pressure scanning tunneling microscopy (HP-STM) and ambient-pressure X-ray photoelectron spectroscopy (AP-XPS) at high gas pressures. HP-STM makes it possible to determine the atomic or molecular rearrangement at catalyst surfaces, particularly at the low-coordinated active surface sites. AP-XPS monitors changes in elemental composition and chemical states of catalysts in response to variations in gas environments. Stepped Pt and Cu single crystals, the hexagonally reconstructed Pt(100) single crystal, and Pt-based bimetallic nanoparticles with controlled size, shape and composition, were employed as the model catalysts for experiments in this thesis.

  1. Simulating solidification in metals at high pressure: The drive to petascale computing

    International Nuclear Information System (INIS)

    Streitz, Frederick H; Glosli, James N; Patel, Mehul V; Chan, Bor; Yates, Robert K; Supinski, Bronis R de; Sexton, James; Gunnels, John A

    2006-01-01

    We investigate solidification in metal systems ranging in size from 64,000 to 524,288,000 atoms on the IBM BlueGene/L computer at LLNL. Using the newly developed ddcMD code, we achieve performance rates as high as 103 TFlops, with a performance of 101.7 TFlop sustained over a 7 hour run on 131,072 cpus. We demonstrate superb strong and weak scaling. Our calculations are significant as they represent the first atomic-scale model of metal solidification to proceed, without finite size effects, from spontaneous nucleation and growth of solid out of the liquid, through the coalescence phase, and into the onset of coarsening. Thus, our simulations represent the first step towards an atomistic model of nucleation and growth that can directly link atomistic to mesoscopic length scales

  2. The valence state of Yb metal under high pressure determined by XANES measurement up to 34.6 GPa

    International Nuclear Information System (INIS)

    Fuse, Akinori; Nakamoto, Go; Kurisu, Makio; Ishimatsu, Naoki; Tanida, Hajime

    2004-01-01

    The purpose of this study was to accurately determine the valency of Yb at high pressure and room temperature and to clarify the relation between the valence state and the crystal structure of Yb metal. L III -edge X-ray absorption near-edge structure (XANES) spectra were measured to determine the valence state of Yb metal in the pressure range from 0 to 34.6 GPa at room temperature, using a diamond anvil cell (DAC) and synchrotron radiation at SPring-8. In the fcc phase, Yb metal exhibits mixed valence (the mean valence ν-bar >2.1). At the fcc-to-bcc phase transition, a 0.1 jump is found in ν-bar. In the bcc phase, ν-bar(P) is an increasing function of pressure with downward curvature, reaching only 2.55 at 26 GPa. The ν-bar is only 2.65 in the hcp phase at 34.6 GPa. A tendency for saturation in ν-bar(P) to values smaller than 3.0 is found

  3. State-of-the-Art of Extreme Pressure Lubrication Realized with the High Thermal Diffusivity of Liquid Metal.

    Science.gov (United States)

    Li, Haijiang; Tian, Pengyi; Lu, Hongyu; Jia, Wenpeng; Du, Haodong; Zhang, Xiangjun; Li, Qunyang; Tian, Yu

    2017-02-15

    Sliding between two objects under very high load generally involves direct solid-solid contact at molecular/atomic level, the mechanism of which is far from clearly disclosed yet. Those microscopic solid-solid contacts could easily lead to local melting of rough surfaces. At extreme conditions, this local melting could propagate to the seizure and welding of the entire interface. Traditionally, the microscopic solid-solid contact is alleviated by various lubricants and additives based on their improved mechanical properties. In this work, we realized the state-of-the-art of extreme pressure lubrication by utilizing the high thermal diffusivity of liquid metal, 2 orders of magnitude higher than general organic lubricants. The extreme pressure lubrication property of gallium based liquid metal (GBLM) was compared with gear oil and poly-α-olefin in a four-ball test. The liquid metal lubricates very well at an extremely high load (10 kN, the maximum capability of a four-ball tester) at a rotation speed of 1800 rpm for a duration of several minutes, much better than traditional organic lubricants which typically break down within seconds at a load of a few kN. Our comparative experiments and analysis showed that this superextreme pressure lubrication capability of GBLM was attributed to the synergetic effect of the ultrafast heat dissipation of GBLM and the low friction coefficient of FeGa 3 tribo-film. The present work demonstrated a novel way of improving lubrication capability by enhancing the lubricant thermal properties, which might lead to mechanical systems with much higher reliability.

  4. The structural properties of Zr-based bulk metallic glasses subjected to high pressure torsion at different temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Boltynjuk, E. V., E-mail: boltynjuk@gmail.com; Ubyivovk, E. V.; Kshumanev, A. M. [Saint Petersburg State University, 28 Universitetskiy pr., Saint Petersburg, 198504 (Russian Federation); Gunderov, D. V.; Lukianov, A. V. [Ufa State Aviation Technical University, K. Marks 12, Ufa, 450000 (Russian Federation); Bednarz, A. [Faculty of Mechanical Engineering and Aeronautics, Department of Aircraft and Aircraft Engines, Rzeszow University of Technology, Al. Powstancow Warszawy 8, 35-959 Rzeszow (Poland); Valiev, R. Z. [Saint Petersburg State University, 28 Universitetskiy pr., Saint Petersburg, 198504 (Russian Federation); Ufa State Aviation Technical University, K. Marks 12, Ufa, 450000 (Russian Federation)

    2016-06-17

    The structural properties of a Zr{sub 62}Cu{sub 22}Al{sub 10}Fe{sub 5}Dy{sub 1} bulk metallic glasses were investigated. Cylindrical rods of the Zr{sub 62}Cu{sub 22}Al{sub 10}Fe{sub 5}Dy{sub 1} BMG were subjected to high pressure torsion at temperatures of 20°C and 150°C. X-ray diffraction, transmission electron microscopy were used to determine peculiarities of the modified structure. Analysis of fracture surfaces, nanohardness measurements were conducted to investigate the influence of structural changes on mechanical behavior of processed samples.

  5. The structural properties of Zr-based bulk metallic glasses subjected to high pressure torsion at different temperatures

    International Nuclear Information System (INIS)

    Boltynjuk, E. V.; Ubyivovk, E. V.; Kshumanev, A. M.; Gunderov, D. V.; Lukianov, A. V.; Bednarz, A.; Valiev, R. Z.

    2016-01-01

    The structural properties of a Zr_6_2Cu_2_2Al_1_0Fe_5Dy_1 bulk metallic glasses were investigated. Cylindrical rods of the Zr_6_2Cu_2_2Al_1_0Fe_5Dy_1 BMG were subjected to high pressure torsion at temperatures of 20°C and 150°C. X-ray diffraction, transmission electron microscopy were used to determine peculiarities of the modified structure. Analysis of fracture surfaces, nanohardness measurements were conducted to investigate the influence of structural changes on mechanical behavior of processed samples.

  6. Investigation of the design of a metal-lined fully wrapped composite vessel under high internal pressure

    Science.gov (United States)

    Kalaycıoğlu, Barış; Husnu Dirikolu, M.

    2010-09-01

    In this study, a Type III composite pressure vessel (ISO 11439:2000) loaded with high internal pressure is investigated in terms of the effect of the orientation of the element coordinate system while simulating the continuous variation of the fibre angle, the effect of symmetric and non-symmetric composite wall stacking sequences, and lastly, a stacking sequence evaluation for reducing the cylindrical section-end cap transition region stress concentration. The research was performed using an Ansys® model with 2.9 l volume, 6061 T6 aluminium liner/Kevlar® 49-Epoxy vessel material, and a service internal pressure loading of 22 MPa. The results show that symmetric stacking sequences give higher burst pressures by up to 15%. Stacking sequence evaluations provided a further 7% pressure-carrying capacity as well as reduced stress concentration in the transition region. Finally, the Type III vessel under consideration provides a 45% lighter construction as compared with an all metal (Type I) vessel.

  7. Composition design of Ti–Cr–Mn–Fe alloys for hybrid high-pressure metal hydride tanks

    Energy Technology Data Exchange (ETDEWEB)

    Cao, Zhijie [School of Materials Science and Engineering, Key Laboratory of Advanced Energy Storage Materials of Guangdong Province, South China University of Technology, Guangzhou 510641 (China); China-Australia Joint Laboratory for Energy & Environmental Materials, South China University of Technology, Guangzhou 510641 (China); Ouyang, Liuzhang, E-mail: meouyang@scut.edu.cn [School of Materials Science and Engineering, Key Laboratory of Advanced Energy Storage Materials of Guangdong Province, South China University of Technology, Guangzhou 510641 (China); China-Australia Joint Laboratory for Energy & Environmental Materials, South China University of Technology, Guangzhou 510641 (China); Key Laboratory for Fuel Cell Technology in Guangdong Province, Guangzhou 510641 (China); Wang, Hui; Liu, Jiangwen [School of Materials Science and Engineering, Key Laboratory of Advanced Energy Storage Materials of Guangdong Province, South China University of Technology, Guangzhou 510641 (China); China-Australia Joint Laboratory for Energy & Environmental Materials, South China University of Technology, Guangzhou 510641 (China); Sun, Lixian [Guangxi Collaborative Innovation Center of Structure and Property for New Energy and Materials, Guilin 541004 (China); Zhu, Min, E-mail: memzhu@scut.edu.cn [School of Materials Science and Engineering, Key Laboratory of Advanced Energy Storage Materials of Guangdong Province, South China University of Technology, Guangzhou 510641 (China); China-Australia Joint Laboratory for Energy & Environmental Materials, South China University of Technology, Guangzhou 510641 (China)

    2015-08-05

    Highlights: • New non-stoichiometric Ti–Cr–Mn–Fe alloys are prepared for the hybrid tank. • (Ti{sub 0.85}Zr{sub 0.15}){sub 1.1}Cr{sub 0.925}MnFe{sub 0.075} has the best overall properties. • The desorption pressure at 0 °C is 10.6 atm. • The reversible gravimetric density remains as a high value of 1.49 wt%. - Abstract: (Ti{sub 0.85}Zr{sub 0.15}){sub 1.1}Cr{sub 1−x}MnFe{sub x} (x = 0, 0.05, 0.075, 0.1, 0.15) alloys with a C14-type Laves structure have been investigated for potential application in hybrid high-pressure metal hydride tanks used for fuel cell vehicles. The effects of the partial substitution of Cr with Fe on the hydrogen storage properties of (Ti{sub 0.85}Zr{sub 0.15}){sub 1.1}CrMn have been systematically investigated. Results show that the desorption plateau pressure increases with increasing the Fe content in (Ti{sub 0.85}Zr{sub 0.15}){sub 1.1}Cr{sub 1−x}MnFe{sub x} alloys, whereas the hydrogen capacity decreases. Among these alloys, (Ti{sub 0.85}Zr{sub 0.15}){sub 1.1}Cr{sub 0.925}MnFe{sub 0.075} has the best overall properties, with a hydrogen desorption pressure of 10.6 atm and a reversible capacity of 1.54 wt% at 0 °C under the pressure range between 0.1 atm and 120 atm.

  8. Composition design of Ti–Cr–Mn–Fe alloys for hybrid high-pressure metal hydride tanks

    International Nuclear Information System (INIS)

    Cao, Zhijie; Ouyang, Liuzhang; Wang, Hui; Liu, Jiangwen; Sun, Lixian; Zhu, Min

    2015-01-01

    Highlights: • New non-stoichiometric Ti–Cr–Mn–Fe alloys are prepared for the hybrid tank. • (Ti 0.85 Zr 0.15 ) 1.1 Cr 0.925 MnFe 0.075 has the best overall properties. • The desorption pressure at 0 °C is 10.6 atm. • The reversible gravimetric density remains as a high value of 1.49 wt%. - Abstract: (Ti 0.85 Zr 0.15 ) 1.1 Cr 1−x MnFe x (x = 0, 0.05, 0.075, 0.1, 0.15) alloys with a C14-type Laves structure have been investigated for potential application in hybrid high-pressure metal hydride tanks used for fuel cell vehicles. The effects of the partial substitution of Cr with Fe on the hydrogen storage properties of (Ti 0.85 Zr 0.15 ) 1.1 CrMn have been systematically investigated. Results show that the desorption plateau pressure increases with increasing the Fe content in (Ti 0.85 Zr 0.15 ) 1.1 Cr 1−x MnFe x alloys, whereas the hydrogen capacity decreases. Among these alloys, (Ti 0.85 Zr 0.15 ) 1.1 Cr 0.925 MnFe 0.075 has the best overall properties, with a hydrogen desorption pressure of 10.6 atm and a reversible capacity of 1.54 wt% at 0 °C under the pressure range between 0.1 atm and 120 atm

  9. THE BEHAVIOR OF SOLUBLE METALS ELUTED FROM Ni/Fe-BASED ALLOY REACTORS AFTER HIGH-TEMPERATURE AND HIGH-PRESSURE WATER PROCESS

    Directory of Open Access Journals (Sweden)

    M. Faisal

    2012-05-01

    Full Text Available The behavior of heavy metals eluted from the wall of Ni/Fe-based alloy reactors after high-temperature and high-pressure water reaction were studied at temperatures ranging from 250 to 400oC. For this purpose, water and cysteic acid were heated in two reactor materials which are SUS 316 and Inconel 625. Under the tested conditions, the erratic behaviors of soluble metals eluted from the wall of Ni/Fe-based alloy in high temperature water were observed. Results showed that metals could be eluted even at a short contact time. The presence of air also promotes elution at sub-critical conditions. At sub-critical conditions, a significant amount of Cr was extracted from SUS 316, while only traces of Ni, Fe, Mo and Mn were eluted. In contrast, Ni was removed in significant amounts compared to Cr when Inconel 625 was tested. It was observed that eluted metals tend to increased under acidic conditions and most of those metals were over the limit of WHO guideline for drinking water. The results are significant both on the viewpoint of environmental regulation on disposal of wastes containing heavy metals, toxicity of resulting product and catalytic effect on a particular reaction.

  10. Zirconium metal-water oxidation kinetics. V. Oxidation of Zircaloy in high pressure steam

    International Nuclear Information System (INIS)

    Pawel, R.E.; Cathcart, J.V.; Campbell, J.J.; Jury, S.H.

    1977-12-01

    A series of scoping tests to determine the influence of steam pressure on the isothermal oxidation kinetics of Zircaloy-4 PWR tubing was undertaken. The oxidation experiments were conducted in flowing steam at 3.45, 6.90, and 10.34 MPa (500, 1000, and 1500 psi) at 905 0 C (1661 0 F), and at 3.45 and 6.90 MPa at 1101 0 C (2014 0 F). A comparison of the results of these experiments with those obtained for oxidation in steam at atmospheric pressure under similar conditions indicated that measurable enhancement of the oxidation rate occurred with increasing pressure at 905 0 C, but not at 1100 0 C

  11. 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 ...

  12. 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 ...

  13. 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 ...

  14. 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.

  15. Study on interfacial heat transfer coefficient at metal/die interface during high pressure die casting process of AZ91D alloy

    Directory of Open Access Journals (Sweden)

    GUO Zhi-peng

    2007-02-01

    Full Text Available The high pressure die casting (HPDC process is one of the fastest growing and most efficient methods for the production of complex shape castings of magnesium and aluminum alloys in today’s manufacturing industry.In this study, a high pressure die casting experiment using AZ91D magnesium alloy was conducted, and the temperature profiles inside the die were Measured. By using a computer program based on solving the inverse heat problem, the metal/die interfacial heat transfer coefficient (IHTC was calculated and studied. The results show that the IHTC between the metal and die increases right after the liquid metal is brought into the cavity by the plunger,and decreases as the solidification process of the liquid metal proceeds until the liquid metal is completely solidified,when the IHTC tends to be stable. The interfacial heat transfer coefficient shows different characteristics under different casting wall thicknesses and varies with the change of solidification behavior.

  16. Plastic Deformation of Pressured Metallic Glass

    Directory of Open Access Journals (Sweden)

    Yun Cheng

    2017-11-01

    Full Text Available Although pressured metallic glass (MG has been reported in the literature; there are few studies focusing on pressure effects on the structure; dynamics and its plastic deformation. In this paper; we report on and characterize; via molecular dynamics simulation, the structure and dynamics heterogeneity of pressured MGs, and explore a causal link between local structures and plastic deformation mechanism of pressured glass. The results exhibit that the dynamical heterogeneity of metallic liquid is more pronounced at high pressure, while the MGs were less fragile after the release of external pressure, reflected by the non-Gaussian parameter (NGP. High pressure glass shows better plastic deformation; and the local strain zone distributed more uniformly than of in normal glass. Further research indicates that although the number of icosahedrons in pressured glass was much larger than that in normal glass, while the interpenetrating connections of icosahedra (ICOI exhibited spatial correlations were rather poor; In addition, the number of ‘fast’ atoms indexed by the atoms’ moving distance is larger than that in normal glass; leading to the sharp decreasing in number of icosahedrons during deformation. An uniform distribution of ‘fast’ atoms also contributed to better plastic deformation ability in the pressured glass. These findings may suggest a link between the deformation and destruction of icosahedra with short-range order.

  17. 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 ...

  18. Experimental improvement of the technology of cutting of high-pressure hoses with metal braid on hand cutting machine

    OpenAIRE

    Karpenko, Mykola; Bogdevicius, Marijonas; Prentkovskis, Olegas

    2016-01-01

    In the article the review of the problem of improvement of technology of high pressure hoses cutting on the hand cutting machines is analyzed. Different methods of cutting of high pressure hoses into the billets are overviewed and the quality of edge cuts of hoses is analyzed. The comparison of treatment on automatic cutting machines and on hand cutting machines is carried out. Different experimental techniques of improvement of the quality of edges cutting of high pressure hoses are prese...

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

    Science.gov (United States)

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

    2016-09-01

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

  20. X-ray absorption tomography of a high-pressure metal-halide lamp with a bent arc due to Lorentz-forces

    NARCIS (Netherlands)

    Denisova, N.; Haverlag, M.; Ridderhof, E.J.; Nimalasuriya, T.; Mullen, van der J.J.A.M.

    2007-01-01

    The arc temperature is one of the most important characteristics which cotrol the emission properties of plasma light sources. X-ray absorption technique has received some attention as a powerful method to determine the temperature in high-pressure metal-halide lamps. An important advantage of x-ray

  1. Impact of various lighting source (incandescent, fluorescent, metal halide and high pressure sodium) on the production performance of chicken broilers

    International Nuclear Information System (INIS)

    Guffar, A.; Rahman, K.U.; Siddique, M.; Ahmad, F.

    2009-01-01

    Light is an important aspect of an animal's environment. Avian as well as mammalian species respond to light energy in a variety of ways. Recent research has indicated that light source may affect body weight, immune response, livability and health status. Broiler behavior is strongly affected by light sources. So the present project was designed to study the effect of light sources on the production performance of broilers. For this purpose, 500 day-old broilers purchased from the local market were reared for three days (adaptation period) in one group. Then these were randomly divided into five experimental groups each comprising of 100 birds. Group A was given 25 incandescent light (INC), Group B was given fluorescent light (FC), Group C was given metal halide light (MH), Group D was given high pressure sodium light (HPS) and Group E was given no light source (control). Performance trial in terms of measurement of weekly body weight, weekly feed consumption, feed conversion ratio (FCR), daily water consumption and mortality were checked. Among various lighting sources, MH proved the best light source regarding main parameters of production performance. (author)

  2. 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 ...

  3. 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 ...

  4. 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 ...

  5. 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, ...

  6. 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...

  7. Phase stability, physical properties of rhenium diboride under high pressure and the effect of metallic bonding on its hardness

    International Nuclear Information System (INIS)

    Zhong, Ming-Min; Kuang, Xiao-Yu; Wang, Zhen-Hua; Shao, Peng; Ding, Li-Ping; Huang, Xiao-Fen

    2013-01-01

    Highlights: •The transition pressure P t between the ReB 2 –ReB 2 and MoB 2 –ReB 2 phases is firstly determinate. •The single-bonded B–B feather remains in ReB 2 compounds. •A semiempirical method to evaluate the hardness of crystals with partial metallic bond is presented. •The large hardness (39.1 GPa) of ReB 2 –ReB 2 indicate that it is a superhard material. •The zigzag interconnected B–Re and B–B covalent bonds underlie the ultraincompressibilities. -- Abstract: Using first-principles calculations, the elastic constants, thermodynamic property and structural phase transition of rhenium diboride under pressure are investigated by means of the pseudopotential plane-waves method, as well as the effect of metallic bond on its hardness. Eight candidate structures of known transition-metal compounds are chosen to probe for rhenium diboride ReB 2 . The calculated lattice parameters are consistent with the experimental and theoretical values. Based on the third order Birch–Murnaghan equation of states, the transition pressure P t between the ReB 2 –ReB 2 and MoB 2 –ReB 2 phases is firstly determinate. Elastic constants, shear modulus, Young’s modulus, Poisson’s ratio and Debye temperature are derived. The single-bonded B–B feather remains in ReB 2 compounds. Furthermore, according to Mulliken overlap population analysis, a semiempirical method to evaluate the hardness of multicomponent crystals with partial metallic bond is presented. Both strong covalency and a zigzag topology of interconnected bonds underlie the ultraincompressibilities. In addition, the superior performance and large hardness (39.1 GPa) of ReB 2 –ReB 2 indicate that it is a superhard material

  8. 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...

  9. The W-W02 Oxygen Fugacity Buffer at High Pressures and Temperatures: Implications for f02 Buffering and Metal-silicate Partitioning

    Science.gov (United States)

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

    2013-01-01

    Oxygen fugacity (fO2) controls multivalent phase equilibria and partitioning of redox-sensitive elements, and it is important to understand this thermodynamic parameter in experimental and natural systems. The coexistence of a metal and its oxide at equilibrium constitutes an oxygen buffer which can be used to control or calculate fO2 in high pressure experiments. Application of 1-bar buffers to high pressure conditions can lead to inaccuracies in fO2 calculations because of unconstrained pressure dependencies. Extending fO2 buffers to pressures and temperatures corresponding to the Earth's deep interior requires precise determinations of the difference in volume (Delta) V) between the buffer phases. Synchrotron x-ray diffraction data were obtained using diamond anvil cells (DAC) and a multi anvil press (MAP) to measure unit cell volumes of W and WO2 at pressures and temperatures up to 70 GPa and 2300 K. These data were fitted to Birch-Murnaghan 3rd-order thermal equations of state using a thermal pressure approach; parameters for W are KT = 306 GPa, KT' = 4.06, and aKT = 0.00417 GPa K-1. Two structural phase transitions were observed for WO2 at 4 and 32 GPa with structures in P21/c, Pnma and C2/c space groups. Equations of state were fitted for these phases over their respective pressure ranges yielding the parameters KT = 190, 213, 300 GPa, KT' = 4.24, 5.17, 4 (fixed), and aKT = 0.00506, 0.00419, 0.00467 GPa K-1 for the P21/c, Pnma and C2/c phases, respectively. The W-WO2 buffer (WWO) was extended to high pressure by inverting the W and WO2 equations of state to obtain phase volumes at discrete pressures (1-bar to 100 GPa, 1 GPa increments) along isotherms (300 to 3000K, 100 K increments). The slope of the absolute fO2 of the WWO buffer is positive with increasing temperature up to approximately 70 GPa and is negative above this pressure. The slope is positive along isotherms from 1000 to 3000K with increasing pressure up to at least 100 GPa. The WWO buffer is at

  10. 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

  11. Measurement of the differential pressure of liquid metals

    Science.gov (United States)

    Metz, H.J.

    1975-09-01

    This patent relates to an improved means for measuring the differential pressure between any two points in a process liquid metal coolant loop, wherein the flow of liquid metal in a pipe is opposed by a permanent magnet liquid metal pump until there is almost zero flow shown by a magnetic type flowmeter. The pressure producing the liquid metal flow is inferred from the rate of rotation of the permanent magnet pump. In an alternate embodiment, a differential pressure transducer is coupled to a process pipeline by means of high-temperature bellows or diaphragm seals, and a permanent magnet liquid metal pump in the high-pressure transmission line to the pressure transducer can be utilized either for calibration of the transducer or for determining the process differential pressure as a function of the magnet pump speed. (auth)

  12. Measurement of the differential pressure of liquid metals

    International Nuclear Information System (INIS)

    Metz, H.J.

    1975-01-01

    This patent relates to an improved means for measuring the differential pressure between any two points in a process liquid metal coolant loop, wherein the flow of liquid metal in a pipe is opposed by a permanent magnet liquid metal pump until there is almost zero flow shown by a magnetic type flowmeter. The pressure producing the liquid metal flow is inferred from the rate of rotation of the permanent magnet pump. In an alternate embodiment, a differential pressure transducer is coupled to a process pipeline by means of high-temperature bellows or diaphragm seals, and a permanent magnet liquid metal pump in the high-pressure transmission line to the pressure transducer can be utilized either for calibration of the transducer or for determining the process differential pressure as a function of the magnet pump speed

  13. 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 ...

  14. Three Toxic Heavy Metals in Open-Angle Glaucoma with Low-Teen and High-Teen Intraocular Pressure: A Cross-Sectional Study from South Korea

    OpenAIRE

    Lee, Si Hyung; Kang, Eun Min; Kim, Gyu Ah; Kwak, Seung Woo; Kim, Joon Mo; Bae, Hyoung Won; Seong, Gong Je; Kim, Chan Yun

    2016-01-01

    Background To investigate the association between heavy metal levels and open-angle glaucoma (OAG) with low- and high-teen baseline intraocular pressure (IOP) using a population-based study design. Methods This cross-sectional study included 5,198 participants older than 19 years of age who participated in the Korean National Health and Nutrition Examination Survey (KNHANES) from 2008 to 2012 and had blood heavy metal levels available. The OAG with normal baseline IOP (IOP ? 21 mmHg) subjects...

  15. 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 ...

  16. 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.

  17. Nuclear reactor pressure vessel with an inner metal coating covered with a high temperature resistant thermal insulator

    International Nuclear Information System (INIS)

    1974-01-01

    The thermal insulator covering the metal coating of a reactor vessel is designed for resisting high temperatures. It comprises one or several porous layers of ceramic fibers or of stacked metal foils, covered with a layer of bricks or ceramic tiles. The latter are fixed in position by fasteners comprising pins fixed to the coating and passing through said porous layers and fasteners (nut or bolts) for individually fixing the bricks to said pins, whereas ceramic plugs mounted on said bricks or tiles provide for the thermal insulation of the pins and of the nuts or bolts; such a thermal insulation can be applied to high-temperature reactors or to fast reactors [fr

  18. Isostructural crystal hydrates of rare-earth metal oxalates at high pressure. From strain anisotropy to dehydration

    Energy Technology Data Exchange (ETDEWEB)

    Zakharov, Boris A.; Matvienko, Alexander A. [Russian Academy of Ssciences, Novosibirsk (Russian Federation). Inst. of Solid State Chemistry and Mechanochemistry; Novosibirsk State Univ. (Russian Federation); Gribov, Pavel A.; Boldyreva, Elena V. [Russian Academy of Ssciences, Novosibirsk (Russian Federation). Inst. of Solid State Chemistry and Mechanochemistry

    2017-07-01

    The crystal structures of a series of isostructural rare-earth metal oxalates, (REE){sub 2}(C{sub 2}O{sub 4}){sub 3}.10H{sub 2}O (REE=Sm, Y) and a 1:1 YSm(C{sub 2}O{sub 4}){sub 3}.10H{sub 2}O solid solution, have been studied in situ by single-crystal X-ray diffraction and optical microscopy. The structures were followed from ambient pressure to 6 GPa in a DAC with paraffin as the hydrostatic fluid. Bulk compressibilities, anisotropic lattice strain on hydrostatic compression and the corresponding changes in the atomic coordinates were followed. Discontinuities/sharp changes in the slopes of the pressure dependences of volume and selected cell parameters have been observed for yttrium-containing salts at ∝3.5 GPa. This may be related to the re-distribution of water molecules within the crystal structure. Y{sub 2}(C{sub 2}O{sub 4}){sub 3}.10H{sub 2}O undergoes a partial dehydration at 1 GPa, forming monoclinic Y{sub 2}(C{sub 2}O{sub 4}){sub 3}.6H{sub 2}O as single-crystalline inclusions in the original phase.

  19. Mineralizer-assisted high-pressure high-temperature synthesis and characterization of novel phosphorus nitride imides and luminescent alkaline earth metal (oxo)nitridophosphates

    International Nuclear Information System (INIS)

    Marchuk, Alexey

    2016-01-01

    The main objectives of this thesis were the synthesis, identification and structural characterization of new alkaline earth metal (oxo)nitridophopshates and phosphorus nitrides. Furthermore, luminescence properties of the resulting materials should be investigated and a connection between these properties and the respective structures should be established. For this purpose, a range of synthesis strategies was employed, including conventional solid-state syntheses in silica ampoules and high-pressure high-temperature syntheses using the multianvil technique. The emphasis of the synthetic part of this thesis lies on the development of new synthetic strategies in order to increase crystallinity of alkaline earth metal (oxo)nitridophosphates and thus accelerate their structure determination. This involves the selection of a suitable mineralizer and the investigation of its interaction with the respective starting materials. In addition, the analytical methods applied in this thesis in order to identify and characterize the compounds are just as essential as the synthesis strategies. X-ray diffraction on single crystals and on powders was carried out as the main analytical method while being supported by quantitative and qualitative 1 H and 31 P solid-state NMR measurements, FTIR and energy-dispersive X-ray (EDX) spectroscopy, as well as electron microscopy methods including both imaging and diffraction techniques. Implied by the large number of novel structures investigated, theoretical studies including topological analysis, calculations of lattice energies and bond-valence sums also played a major role in this thesis. Optical analysis methods such as reflectance spectroscopy, luminescence microscopy and photoluminescence measurements helped to determine the luminescence properties of some of the presented compounds.

  20. 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 ...

  1. 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 ...

  2. 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

  3. 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

  4. Shock response of porous metals: characterization of pressure field

    International Nuclear Information System (INIS)

    Xu Aiguo; Zhang Guangcai; Hao Pengcheng; Dong Yinfeng; Wei Xijun; Zhu Jianshi

    2012-01-01

    Shock wave reaction on porous metals is numerically simulated. When the pressure threshold is low, the increasing rate of high-pressure area gives roughly the propagation velocity of the compressive waves in the porous material. and the wave front in the condensed pressure map is nearly a plane: with the increasing of pressure threshold. more low-pressure-spots appear in the high-pressure background, and neighboring spots may coalesce, consequently, the topology of the pressure Turing pattern may change. The deviation from linearity of the increasing rate of high-pressure area is a pronounced effect of porous material under shock. The stronger the initial shock, the more pronounced the porosity effects. When the initial yield of material becomes higher, the material shows more elastic behaviors and the less porous effects, compressive and tension waves propagate more quickly, and the porous material becomes less compressible. (authors)

  5. Compressibility measurements and phonon spectra of hexagonal transition-metal nitrides at high pressure: ε-TaN, δ-MoN, and Cr2N

    International Nuclear Information System (INIS)

    Soignard, Emmanuel; Shebanova, Olga; McMillan, Paul F.

    2007-01-01

    We report compressibility measurements for three transition metal nitrides (ε-TaN, δ-MoN, Cr 2 N) that have structures based on hexagonal arrangements of the metal atoms. The studies were performed using monochromatic synchrotron x-ray diffraction at high pressure in a diamond anvil cell. The three nitride compounds are well-known high hardness materials, and they are found to be highly incompressible. The bulk modulus values measured for ε-TaN, Cr 2 N, and δ-MoN are K 0 =288(6) GPa, 275(23) GPa, and 345(9) GPa, respectively. The data were analyzed using a linearized plot of reduced pressure (F) vs the Eulerian finite strain variable f within a third-order Birch-Murnaghan equation of state formulation. The K 0 ' values for ε-TaN and δ-MoN were 4.7(0.5) and 3.5(0.3), respectively, close to the value of K 0 ' =4 that is typically assumed in fitting compressibility data in equation of state studies using a Birch-Murnaghan equation. However, Cr 2 N was determined to have a much smaller value, K 0 ' =2.0(2.0), indicating a significantly smaller degree of structural stiffening with increased pressure. We also present Raman data for ε-TaN and δ-MoN at high pressure in order to characterize the phonon behavior in these materials. All of the Raman active modes for ε-TaN were identified using polarized spectroscopy. Peaks at low frequency are due to Ta motions, whereas modes at higher wave number contain a large component of N motion. The high frequency modes associated with Ta-N stretching vibrations are more sensitive to compression than the metal displacements occurring at lower wave number. The mode assignments can be generally extended to δ-MoN, that has a much more complex Raman spectrum. The x-ray and Raman data for ε-TaN show evidence for structural disordering occurring above 20 GPa, whereas no such change is observed for δ-MoN

  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. 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.)

  8. Effects of carbonyl bond, metal cluster dissociation, and evaporation rates on predictions of nanotube production in high-pressure carbon monoxide

    Science.gov (United States)

    Scott, Carl D.; Smalley, Richard E.

    2003-01-01

    The high-pressure carbon monoxide (HiPco) process for producing single-wall carbon nanotubes (SWNTs) uses iron pentacarbonyl as the source of iron for catalyzing the Boudouard reaction. Attempts using nickel tetracarbonyl led to no production of SWNTs. This paper discusses simulations at a constant condition of 1300 K and 30 atm in which the chemical rate equations are solved for different reaction schemes. A lumped cluster model is developed to limit the number of species in the models, yet it includes fairly large clusters. Reaction rate coefficients in these schemes are based on bond energies of iron and nickel species and on estimates of chemical rates for formation of SWNTs. SWNT growth is measured by the conformation of CO2. It is shown that the production of CO2 is significantly greater for FeCO because of its lower bond energy as compared with that of NiCO. It is also shown that the dissociation and evaporation rates of atoms from small metal clusters have a significant effect on CO2 production. A high rate of evaporation leads to a smaller number of metal clusters available to catalyze the Boudouard reaction. This suggests that if CO reacts with metal clusters and removes atoms from them by forming MeCO, this has the effect of enhancing the evaporation rate and reducing SWNT production. The study also investigates some other reactions in the model that have a less dramatic influence.

  9. Equipment for liquid metal pressure measurement

    International Nuclear Information System (INIS)

    Jung, J.

    1977-01-01

    Equipment is proposed for measuring liquid metal pressure in piping or a tank. An auxiliary piping is connected to the piping or tank at the measuring point. The auxiliary piping transports liquid metal to a container by means of an electromagnetic pump. The piping also houses an electromagnetic flow ratemeter connected to an electric comparator. The comparator and the electromagnetic pump are connected to the pump output generator. (Z.M.)

  10. 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.

  11. 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.

  12. Three Toxic Heavy Metals in Open-Angle Glaucoma with Low-Teen and High-Teen Intraocular Pressure: A Cross-Sectional Study from South Korea.

    Directory of Open Access Journals (Sweden)

    Si Hyung Lee

    Full Text Available To investigate the association between heavy metal levels and open-angle glaucoma (OAG with low- and high-teen baseline intraocular pressure (IOP using a population-based study design.This cross-sectional study included 5,198 participants older than 19 years of age who participated in the Korean National Health and Nutrition Examination Survey (KNHANES from 2008 to 2012 and had blood heavy metal levels available. The OAG with normal baseline IOP (IOP ≤ 21 mmHg subjects were stratified into low-teen OAG (baseline IOP ≤ 15 mmHg and high-teen OAG (15 mmHg < baseline IOP ≤ 21 mmHg, and the association between blood lead, mercury, and cadmium levels and glaucoma prevalence was assessed for low- and high-teen OAG.The adjusted geometric mean of blood cadmium levels was significantly higher in subjects with low-teen OAG than that of the non-glaucomatous group (P = 0.028, whereas there were no significant differences in blood lead and mercury levels. After adjusting for potential confounders, the low-teen OAG was positively associated with log-transformed blood cadmium levels (OR, 1.41; 95% confidence interval (CI, 1.03-1.93; P = 0.026. For high-teen OAG, log-transformed blood levels of the three heavy metals were not associated with disease prevalence. The association between log-transformed blood cadmium levels and low-teen OAG was significant only in men (OR, 1.65; 95% CI, 1.10-2.48; P = 0.016, and not in women (OR, 1.10; 95% CI, 0.66-1.85; P = 0.709.The results of this study suggest that cadmium toxicity could play a role in glaucoma pathogenesis, particularly in men and in OAG with low-teen baseline IOP.

  13. 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

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

    International Nuclear Information System (INIS)

    Saario, T.; Marichev, V.A.

    1993-01-01

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

  15. 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.)

  16. 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 ...

  17. 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 ...

  18. 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 ...

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2017-02-15

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

  20. Ambient pressure photoemission spectroscopy of metal surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Baikie, Iain D., E-mail: iain@kptechnology.ltd.uk; Grain, Angela C.; Sutherland, James; Law, Jamie

    2014-12-30

    Highlights: • Ambient pressure photoemission spectroscopy of metals. • Rastered photon energy scan overcomes inelastic scattering. • Relationship between photoemission threshold and contact potential difference. - Abstract: We describe a novel photoemission technique utilizing a traditional Kelvin probe as a detector of electrons/atmospheric ions ejected from metallic surfaces (Au, Ag, Cu, Fe, Ni, Ti, Zn, Al) illuminated by a deep ultra-violet (DUV) source under ambient pressure. To surmount the limitation of electron scattering in air the incident photon energy is rastered rather than applying a variable retarding electric field as is used with UPS. This arrangement can be applied in several operational modes: using the DUV source to determine the photoemission threshold (Φ) with 30–50 meV resolution and also the Kelvin probe, under dark conditions, to measure contact potential difference (CPD) between the Kelvin probe tip and the metallic sample with an accuracy of 1–3 meV. We have studied the relationship between the photoelectric threshold and CPD of metal surfaces cleaned in ambient conditions. Inclusion of a second spectroscopic visible source was used to confirm a semiconducting oxide, possibly Cu{sub 2}O, via surface photovoltage measurements with the KP. This dual detection system can be easily extended to controlled gas conditions, relative humidity control and sample heating/cooling.

  1. Comparison of Conventional Deep Drawing, Hydromechanical Deep-Drawing and High Pressure Sheet Metal Forming by Numerical Experiments

    International Nuclear Information System (INIS)

    Oender, I. Erkan; Tekkaya, A. Erman

    2005-01-01

    Increasing use of new technologies in automotive and aircraft applications requires intensive research and developments on sheet metal forming processes. This study focuses on the assessment of sheet hydroforming, hydro-mechanical deep drawing and conventional deep-drawing processes by performing a systematic analysis by numerical simulations. Circular, elliptic, rectangular and square cross-section cups have been selected for the geometry spectrum. Within the range of each cross section, depth, drawing ratio and fillet radii have been altered systematically. St14 stainless steel has been used as the material throughout the study. The deformation behavior has been described by an elasto-plastic material model and all numerical simulations have been carried out by using a dynamic-explicit commercial finite element code. During the analyses each workpiece is produced by the three competing processes. The analyses results such as sheet thickness distribution, necking, forming of radii etc., are used for assessing the success of each forming process alternative. The analyses revealed that depending on the workpiece geometry and dimensional properties certain processes are preferable for obtaining satisfactory products. The process windows for each process have been established based on the analyzed parameters of the three different product geometries. This data is expected to be useful for selecting the appropriate production process for a given workpiece geometry

  2. 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 ...

  3. 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

  4. 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 ...

  5. 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)

  6. Disintegration of liquid metals by low pressure water blasting

    International Nuclear Information System (INIS)

    Heshmatpour, B.; Copeland, G.L.

    1981-01-01

    The feasibility of disintegrating metals by a low cost system and subsequently incorporating them into grout mixtures has been demonstrated. A low pressure water blasting technique consisting of multiple nozzles and a converging-line jet stream was developed to disintegrate liquid metals and produce coarse metal powder and shot. Molten iron resulted in spherical shot, while copper, aluminum, and tin produced irregular shaped particles. The particle size was between 0.05 and 3 mm (0.002 and 0.1 in.), and about half the particles were smaller than 1 mm (0.04 in.) in all cases. The water consumption was rather low, while the production rate was relatively high. The method proved to be simple and reliable. The coarse metal powders were suspendable in grout fluids, indicating that they are probably disposable by the shale hydrofracture technique

  7. 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 ...

  8. 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)

  9. 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) ( ...

  10. 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

  11. 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.

  12. Solids, liquids, and gases under high pressure

    Science.gov (United States)

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

    2018-01-01

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

  13. Electrical conductivity of metal powders under pressure

    Science.gov (United States)

    Montes, J. M.; Cuevas, F. G.; Cintas, J.; Urban, P.

    2011-12-01

    A model for calculating the electrical conductivity of a compressed powder mass consisting of oxide-coated metal particles has been derived. A theoretical tool previously developed by the authors, the so-called `equivalent simple cubic system', was used in the model deduction. This tool is based on relating the actual powder system to an equivalent one consisting of deforming spheres packed in a simple cubic lattice, which is much easier to examine. The proposed model relates the effective electrical conductivity of the powder mass under compression to its level of porosity. Other physically measurable parameters in the model are the conductivities of the metal and oxide constituting the powder particles, their radii, the mean thickness of the oxide layer and the tap porosity of the powder. Two additional parameters controlling the effect of the descaling of the particle oxide layer were empirically introduced. The proposed model was experimentally verified by measurements of the electrical conductivity of aluminium, bronze, iron, nickel and titanium powders under pressure. The consistency between theoretical predictions and experimental results was reasonably good in all cases.

  14. 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

  15. 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

  16. 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

  17. A study of the diffusion mechanisms in amorphous metallic alloys: diffusion and diffusion under high pressure in an amorphous NiZr alloy

    International Nuclear Information System (INIS)

    Grandjean, A.

    1996-01-01

    The aim of this work is a better understanding of the diffusion mechanism in amorphous metallic alloys. Then interdiffusion and hafnium diffusion in amorphous NiZr alloy have been studied. Samples used are made by sputtering co-deposition under vacuum and are well relaxed before the diffusion measurements. The time evolution of resistivity during annealing due to the decay of a composition modulated film has been measured and from this change in resistivity interdiffusion coefficients have been determined. Dependence of Hf diffusion on temperature and pressure has been studied using (SIMS). In this two cases, the diffusion process obeys an Arrhenius law and gives an activation energy of 1.33 eV for interdiffusion, and 0.76 eV for Hf diffusion. An effect of pressure on Hf diffusion has been found leading to an activation volume of 8.5 angstrom 3 . Thanks to these results, two approaches of the diffusion mechanisms in these systems have been proposed. The first comes from a comparison with the diffusion mechanisms in crystalline metals, that is to say by point defects. The second is an hypothesis of collective motions in these non crystalline alloys. (author)

  18. 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

  19. Higher Urinary Heavy Metal, Phthalate, and Arsenic but Not Parabens Concentrations in People with High Blood Pressure, U.S. NHANES, 2011–2012

    Directory of Open Access Journals (Sweden)

    Ivy Shiue

    2014-06-01

    Full Text Available Link between environmental chemicals and human health has emerged but not been completely examined in risk factors. Therefore, it was aimed to study the relationships of different sets of urinary environmental chemical concentrations and risk of high blood pressure (BP in a national, population-based study. Data were retrieved from United States National Health and Nutrition Examination Surveys, 2011–2012 including demographics, BP readings, and urinary environmental chemical concentrations. Analyses included chi-square test, t-test and survey-weighted logistic regression modeling. After full adjustment (adjusting for urinary creatinine, age, sex, ethnicity, and body mass index, urinary cesium (OR 1.56, 95%CI 1.11–2.20, P = 0.014, molybden (OR 1.46, 95%CI 1.06–2.01, P = 0.023, manganese (OR 1.42, 95%CI 1.09–1.86, P = 0.012, lead (OR 1.58, 95%CI 1.28–1.96, P < 0.001, tin (OR 1.44, 95%CI 1.25–1.66, P < 0.001, antimony (OR 1.39, 95%CI 1.10–1.77, P = 0.010, and tungsten (OR 1.49, 95%CI 1.25–1.77, P < 0.001 concentrations were observed to be associated with high BP. People with higher urinary mono-2-ethyl-5-carboxypentyl phthalate (OR 1.33, 95%CI 1.00–1.62, P = 0.006, mono-n-butyl phthalate (OR 1.35, 95%CI 1.13–1.62, P = 0.002, mono-2-ethyl-5-hydroxyhexyl (OR 1.25, 95%CI 1.05–1.49, P = 0.014, mono-n-methyl phthalate (OR 1.26, 95%CI 1.07–1.48, P = 0.007, mono-2-ethyl-5-oxohexyl (OR 1.25, 95%CI 1.07–1.48, P = 0.009, and monobenzyl phthalate (OR 1.40, 95%CI 1.15–1.69, P = 0.002 tended to have high BP as well. However, there are no clear associations between environmental parabens and high BP, nor between pesticides and high BP. In addition, trimethylarsine oxide (OR 2.47, 95%CI 1.27–4.81, P = 0.011 and dimethylarsonic acid concentrations (OR 1.42, 95%CI 1.12–1.79, P = 0.006 were seen to be associated with high BP. In sum, urinary heavy metal, phthalate, and arsenic concentrations were associated with high BP, although the

  20. 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.

  1. 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 ...

  2. 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.

  3. 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 ...

  4. 14 CFR 23.571 - Metallic pressurized cabin structures.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Metallic pressurized cabin structures. 23... AIRCRAFT AIRWORTHINESS STANDARDS: NORMAL, UTILITY, ACROBATIC, AND COMMUTER CATEGORY AIRPLANES Structure Fatigue Evaluation § 23.571 Metallic pressurized cabin structures. For normal, utility, and acrobatic...

  5. 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 ...

  6. Oxygen pressure manipulations on the metal-insulator transition characteristics of highly (011)-oriented vanadium dioxide films grown by magnetron sputtering

    International Nuclear Information System (INIS)

    Yu Qian; Li Wenwu; Duan Zhihua; Hu Zhigao; Chu Junhao; Liang Jiran; Chen Hongda; Liu Jian

    2013-01-01

    The metal-insulator transition behaviour of vanadium dioxide (VO 2 ) films grown at different oxygen pressures is investigated. With the aid of temperature-dependent electrical and infrared transmittance experiments, it is found that the transition temperature in the heating process goes up with increasing argon-oxygen ratio, whereas the one in the cooling process shows an inverse variation trend. It is found that the hysteresis width of the phase transition is narrowed at a lower argon-oxygen ratio because the defects introduced by excess oxygen lower the energy requirement of transformation. Furthermore, the defects reduce the forbidden gap of the VO 2 system due to the generation of a V 5+ ion. The present results are valuable for the achievement of VO 2 -based optoelectronic devices.

  7. 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

  8. Applicable technical method for freeze-substitution of high pressure ...

    African Journals Online (AJOL)

    bmshsj

    2011-11-02

    Quintana, 1994) are available for the microscopic visualization of intracellular organelles. Cryo- fixation, plunge freezing, propane jet freezing, cold metal block freezing, and high pressure freezing provide advantages over chemical ...

  9. 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...

  10. 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.)

  11. 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

  12. 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, ...

  13. 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 ...

  14. 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 ...

  15. 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

  16. 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...

  17. 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.

  18. 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.

  19. 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

  20. 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.

  1. Cu-TDPAT, an rht -type dual-functional metal-organic framework offering significant potential for use in H 2 and natural gas purification processes operating at high pressures

    KAUST Repository

    Wu, Haohan; Yao, Kexin; Zhu, Yihan; Li, Baiyan; Shi, Zhan; Krishna, Rajamani A A; Li, Jing

    2012-01-01

    The separations of CO 2/CO/CH 4/H 2, CO 2/H 2, CH 4/H 2, and CO 2/CH 4 mixtures at pressures ranging to 7 MPa are important in a variety of contexts, including H 2 production, natural gas purification, and fuel-gas processing. The primary objective of this study is to demonstrate the selective adsorption potential of an rht-type metal-organic framework [Cu 3(TDPAT)(H 2O) 3]·10H 2O·5DMA (Cu-TDPAT), possessing a high density of both open metal sites and Lewis basic sites. Experimental high pressure pure component isotherm data for CO 2, CO, CH 4, and H 2 are combined with the Ideal Adsorbed Solution Theory (IAST) for estimation of mixture adsorption equilibrium. The separation performance of Cu-TDPAT is compared with four other microporous materials, specifically chosen in order to span a wide range of physicochemical characteristics: MgMOF-74, MIL-101, LTA-5A, and NaX. For all mixtures investigated, the capacity of Cu-TDPAT to produce the desired product, H 2 or CH 4, satisfying stringent purity requirements, in a fixed bed operating at pressures exceeding about 4 MPa, is either comparable to, or exceeds, that of other materials. © 2012 American Chemical Society.

  2. Cu-TDPAT, an rht -type dual-functional metal-organic framework offering significant potential for use in H 2 and natural gas purification processes operating at high pressures

    KAUST Repository

    Wu, Haohan

    2012-08-09

    The separations of CO 2/CO/CH 4/H 2, CO 2/H 2, CH 4/H 2, and CO 2/CH 4 mixtures at pressures ranging to 7 MPa are important in a variety of contexts, including H 2 production, natural gas purification, and fuel-gas processing. The primary objective of this study is to demonstrate the selective adsorption potential of an rht-type metal-organic framework [Cu 3(TDPAT)(H 2O) 3]·10H 2O·5DMA (Cu-TDPAT), possessing a high density of both open metal sites and Lewis basic sites. Experimental high pressure pure component isotherm data for CO 2, CO, CH 4, and H 2 are combined with the Ideal Adsorbed Solution Theory (IAST) for estimation of mixture adsorption equilibrium. The separation performance of Cu-TDPAT is compared with four other microporous materials, specifically chosen in order to span a wide range of physicochemical characteristics: MgMOF-74, MIL-101, LTA-5A, and NaX. For all mixtures investigated, the capacity of Cu-TDPAT to produce the desired product, H 2 or CH 4, satisfying stringent purity requirements, in a fixed bed operating at pressures exceeding about 4 MPa, is either comparable to, or exceeds, that of other materials. © 2012 American Chemical Society.

  3. 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

  4. 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.)

  5. 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 ...

  6. 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...

  7. 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

  8. 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

  9. 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

  10. Helium atmospheric pressure plasma jets touching dielectric and metal surfaces

    Science.gov (United States)

    Norberg, Seth A.; Johnsen, Eric; Kushner, Mark J.

    2015-07-01

    Atmospheric pressure plasma jets (APPJs) are being investigated in the context plasma medicine and biotechnology applications, and surface functionalization. The composition of the surface being treated ranges from plastics, liquids, and biological tissue, to metals. The dielectric constant of these materials ranges from as low as 1.5 for plastics to near 80 for liquids, and essentially infinite for metals. The electrical properties of the surface are not independent variables as the permittivity of the material being treated has an effect on the dynamics of the incident APPJ. In this paper, results are discussed from a computational investigation of the interaction of an APPJ incident onto materials of varying permittivity, and their impact on the discharge dynamics of the plasma jet. The computer model used in this investigation solves Poisson's equation, transport equations for charged and neutral species, the electron energy equation, and the Navier-Stokes equations for the neutral gas flow. The APPJ is sustained in He/O2 = 99.8/0.2 flowing into humid air, and is directed onto dielectric surfaces in contact with ground with dielectric constants ranging from 2 to 80, and a grounded metal surface. Low values of relative permittivity encourage propagation of the electric field into the treated material and formation and propagation of a surface ionization wave. High values of relative permittivity promote the restrike of the ionization wave and the formation of a conduction channel between the plasma discharge and the treated surface. The distribution of space charge surrounding the APPJ is discussed.

  11. High temperature metallic recuperator

    Science.gov (United States)

    Ward, M. E.; Solmon, N. G.; Smeltzer, C. E.

    1981-06-01

    An industrial 4.5 MM Btu/hr axial counterflow recuperator, fabricated to deliver 1600 F combustion air, was designed to handle rapid cyclic loading, a long life, acceptable costs, and a low maintenance requirement. A cost benefit anlysis of a high temperature waste heat recovery system utilizing the recurperator and components capable of 1600 F combustion air preheat shows that this system would have a payback period of less than two years. Fifteen companies and industrial associations were interviewed and expressed great interest in recuperation in large energy consuming industries. Determination of long term environmental effects on candidate recuperator tubing alloys was completed. Alloys found to be acceptable in the 2200 F flue gas environment of a steel billet reheat furnace, were identified.

  12. 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)

  13. Pressure-induced metal-insulator transition in spinel compound CuV2S4

    International Nuclear Information System (INIS)

    Okada, H.; Koyama, K.; Hedo, M.; Uwatoko, Y.; Watanabe, K.

    2008-01-01

    In order to investigate the pressure effect on electrical properties of CuV 2 S 4 , we performed the electrical resistivity measurements under high pressures up to 8 GPa for a high-quality polycrystalline sample. The charge density wave (CDW) transition temperatures increase with increasing pressure. The residual resistivity rapidly increases with increasing pressure over 4 GPa, and the temperature dependence of the electrical resistivity at 8 GPa exhibits a semiconducting behavior below about 150 K, indicating that a pressure-induced metal-insulator transition occurs in CuV 2 S 4 at 8 GPa

  14. 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.

  15. 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%

  16. 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.

  17. Paramagnetic susceptibility of the Zr{sub 62}Cu{sub 22}Al{sub 10}Fe{sub 5}Dy{sub 1} metallic glass subjected to high-pressure torsion deformation

    Energy Technology Data Exchange (ETDEWEB)

    Korolev, A.V., E-mail: korolyov@imp.uran.ru [Institute of Metal Physics of the Ural Branch RAS, Ekaterinburg (Russian Federation); Ural Federal University, Ekaterinburg (Russian Federation); Kourov, N.I. [Institute of Metal Physics of the Ural Branch RAS, Ekaterinburg (Russian Federation); Pushin, V.G. [Institute of Metal Physics of the Ural Branch RAS, Ekaterinburg (Russian Federation); Ural Federal University, Ekaterinburg (Russian Federation); Gunderov, D.V. [Saint-Petersburg State University, Saint-Petersburg (Russian Federation); Ufa State Aviation Technical University, Ufa (Russian Federation); Boltynjuk, E.V.; Ubyivovk, E.V. [Saint-Petersburg State University, Saint-Petersburg (Russian Federation); Valiev, R.Z. [Saint-Petersburg State University, Saint-Petersburg (Russian Federation); Ufa State Aviation Technical University, Ufa (Russian Federation)

    2017-09-01

    Highlights: • Zr-based BMG was subjected to HPT at temperatures of 20 °C and 150 °C. • Magnetic measurements reveal well recordable changes in paramagnetic susceptibility. • Paramagnetic susceptibility may be an indicator of a change in the structural state. - Abstract: The Zr{sub 62}Cu{sub 22}Al{sub 10}Fe{sub 5}Dy{sub 1} bulk metallic glass is studied in the as-cast state and in the state after processing by high-pressure torsion at temperatures of 20 °C and 150 °C. According to the data from X-ray diffraction and transmission electron microscopy, the structural state of the samples depends weakly on the conducted processing. At the same time, magnetic measurements reveal well recordable changes in paramagnetic susceptibility induced by the processing of the samples. It is assumed that, because of high-pressure torsion deformation, there occurs a noticeable change in the material electronic structure, which leads to a change in the full susceptibility of the samples. The performed studies demonstrate that paramagnetic susceptibility may be an indicator of a change in the structural state of paramagnetic amorphous metallic substances.

  18. Unexpected pressure induced ductileness tuning in sulfur doped polycrystalline nickel metal

    Directory of Open Access Journals (Sweden)

    Cheng Guo

    2018-02-01

    Full Text Available The sulfur induced embrittlement of polycrystalline nickel (Ni metal has been a long-standing mystery. It is suggested that sulfur impurity makes ductile Ni metal brittle in many industry applications due to various mechanisms, such as impurity segregation and disorder-induced melting etc. Here we report an observation that the most ductile measurement occurs at a critical sulfur doping concentration, 14 at.% at pressure from 14 GPa up to 29 GPa through texture evolution analysis. The synchrotron-based high pressure texturing measurements using radial diamond anvil cell (rDAC X-ray diffraction (XRD techniques reveal that the activities of slip systems in the polycrystalline nickel metal are affected by sulfur impurities and external pressures, giving rise to the changes in the plastic deformation of the nickel metal. Dislocation dynamics (DD simulation on dislocation density and velocity further confirms the pressure induced ductilization changes in S doped Ni metal. This observation and simulation suggests that the ductilization of the doped polycrystalline nickel metal can be optimized by engineering the sulfur concentration under pressure, shedding a light on tuning the mechanical properties of this material for better high pressure applications.

  19. Unexpected pressure induced ductileness tuning in sulfur doped polycrystalline nickel metal

    Science.gov (United States)

    Guo, Cheng; Yang, Yan; Tan, Liuxi; Lei, Jialin; Guo, Shengmin; Chen, Bin; Yan, Jinyuan; Yang, Shizhong

    2018-02-01

    The sulfur induced embrittlement of polycrystalline nickel (Ni) metal has been a long-standing mystery. It is suggested that sulfur impurity makes ductile Ni metal brittle in many industry applications due to various mechanisms, such as impurity segregation and disorder-induced melting etc. Here we report an observation that the most ductile measurement occurs at a critical sulfur doping concentration, 14 at.% at pressure from 14 GPa up to 29 GPa through texture evolution analysis. The synchrotron-based high pressure texturing measurements using radial diamond anvil cell (rDAC) X-ray diffraction (XRD) techniques reveal that the activities of slip systems in the polycrystalline nickel metal are affected by sulfur impurities and external pressures, giving rise to the changes in the plastic deformation of the nickel metal. Dislocation dynamics (DD) simulation on dislocation density and velocity further confirms the pressure induced ductilization changes in S doped Ni metal. This observation and simulation suggests that the ductilization of the doped polycrystalline nickel metal can be optimized by engineering the sulfur concentration under pressure, shedding a light on tuning the mechanical properties of this material for better high pressure applications.

  20. 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.)

  1. Pressure-induced polyamorphism in lanthanide-solute metallic glasses

    Energy Technology Data Exchange (ETDEWEB)

    Li, Liangliang; Li, Renfeng; Liu, Haozhe [Harbin Institute of Technology, Harbin (China); Center for High Pressure Science Technology Advanced Research, Changchun (China); Wang, Luhong [Harbin Institute of Technology, Harbin (China); Qu, Dongdong [School of Mechanical and Mining Engineering, The University of Queensland, Brisbane, QLD (Australia); Zhao, Haiyan [X-ray Science Division, Advanced Photon Source, Argonne National Laboratory, Argonne, IL (United States); Center for Advanced Energy Studies, University of Idaho, Idaho Falls, ID (United States); Chapman, Karena W.; Chupas, Peter J. [X-ray Science Division, Advanced Photon Source, Argonne National Laboratory, Argonne, IL (United States)

    2017-06-15

    The electronic structure inheritance of lanthanide-solvent atoms in lanthanide-based metallic glasses has been proposed. Is a polyamorphism possible in lanthanide-solute metallic glasses? So far, polyamorphic phase transitions in metallic glass containing lanthanide have been observed only in lanthanide-solvent metallic glasses. Here, a pressure-induced transition between two distinct amorphous states, accompanied by a 7% volume collapse at ambient pressure, was observed in La{sub 43.4}Pr{sub 18.6}Al{sub 14}Cu{sub 24} metallic glass, with low lanthanide content, by using in situ X-ray total scattering method. The transformation also indicated by changes in short range and medium range order. Thus, it is proposed that the lanthanide-solute metallic glasses also inherit 4f electronic transition from pure lanthanide element in polyamorphic transition. This discovery offers a supplement to research on lanthanide-based metallic glasses, which further provides a new perspective of the polyamorphic transformation in metallic glasses containing lanthanide element. (copyright 2017 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  2. Crystal structure of actinide metals at high compression

    International Nuclear Information System (INIS)

    Fast, L.; Soederlind, P.

    1995-08-01

    The crystal structures of some light actinide metals are studied theoretically as a function of applied pressure. The first principles electronic structure theory is formulated in the framework of density functional theory, with the gradient corrected local density approximation of the exchange-correlation functional. The light actinide metals are shown to be well described as itinerant (metallic) f-electron metals and generally, they display a crystal structure which have, in agreement with previous theoretical suggestions, increasing degree of symmetry and closed-packing upon compression. The theoretical calculations agree well with available experimental data. At very high compression, the theory predicts closed-packed structures such as the fcc or the hcp structures or the nearly closed-packed bcc structure for the light actinide metals. A simple canonical band picture is presented to explain in which particular closed-packed form these metals will crystallize at ultra-high pressure

  3. Properties of heavy alkali metals under pressure

    International Nuclear Information System (INIS)

    Eremenko, T.M.; Zarochentsev, E.V.

    1980-01-01

    Zero isotherms, polymorphic phase body-centered cubic (BCC)-faced-centered cubic (FCC) transitions and K, Rb and Cs phonon spectra have been calculated within the framework of a pseudopotential model added with a short-range repulsion of frames in the Born-Mayer form. It is shown that taking into account Esub(SR) zero isotherms and phonon frequencies change insignificantly; microscopic Grueneisen parameters change by 10-20 % and BCC-FCC transition pressure decreases several times. The agreement of theoretic and experimentally observed characteristics of the transition in Cs and K and Rb phonon spectra is quite satisfactory

  4. Pressure brazing of ceramics to metals with copper solder

    International Nuclear Information System (INIS)

    Pavlova, M.A.; Metelkin, I.I.

    1986-01-01

    The effect on the quality of joints brazed with copper of different non metallized aluminooxide dielectrics with metals and alloys of a series of technological parameters (temperature, pressure, holding, and medium) in the course of pressure brazing is investigated. It is shown that in case of brazing with kovar and nickel the character of dependences is identical, however in all cases the joints with nickel are more durable. For the ceramics - molybdenum system characterized by weak interaction with copper solder kinetic dependences have no maximum and only under holding of more than 20 min the constant strength of 150-190 MPa is attained

  5. 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.

  6. 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)

  7. Pre-service Acoustic Emission Testing for Metal Pressure Vessel

    International Nuclear Information System (INIS)

    Lee, Jong O; Yoon, Woon Ha; Lee, Tae Hee; Lee, Jong Kyu

    2003-01-01

    The field application of acoustic emission(AE) testing for brand-new metal pressure vessel were performed. We will introduce the test procedure for acoustic emission test such as instrument check distance between sensors, sensor location, whole system calibration, pressurization sequence, noise reduction and evaluation. The data of acoustic emission test contain many noise signal, these noise can be reduced by time filtering which based on the description of observation during AE test

  8. 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. ...

  9. 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 ...

  10. 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 ...

  11. 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 ...

  12. 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.

  13. 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.

  14. Combined high-pressure cell-ultrahigh vacuum system for fast testing of model metal alloy catalysts using scanning mass spectrometry

    DEFF Research Database (Denmark)

    Johansson, Martin; Jørgensen, Jan Hoffmann; Chorkendorff, Ib

    2004-01-01

    and gas sampling device over the sample surface. The gas sampled is analyzed with mass spectrometry. Experiments can be made at pressures up to 1 bar and temperatures up to 500 °C. It is shown that the lateral resolution is better than 0.2 mm and that up to 20 circular spots, 1 mm in diameter, can...

  15. Liquid-metal pin-fin pressure drop by correlation in cross flow

    International Nuclear Information System (INIS)

    Wang, Zhibi; Kuzay, T.M.; Assoufid, L.

    1994-01-01

    The pin-fin configuration is widely used as a heat transfer enhancement method in high-heat-flux applications. Recently, the pin-fin design with liquid-metal coolant was also applied to synchrotron-radiation beamline devices. This paper investigates the pressure drop in a pin-post design beamline mirror with liquid gallium as the coolant. Because the pin-post configuration is a relatively new concept, information in literature about pin-post mirrors or crystals is rare, and information about the pressure drop in pin-post mirrors with liquid metal as the coolant is even more sparse. Due to this the authors considered the cross flow in cylinder-array geometry, which is very similar to that of the pin-post, to examine the pressure drop correlation with liquid metals over pin fins. The cross flow of fluid with various fluid characteristics or properties through a tube bank was studied so that the results can be scaled to the pin-fin geometry with liquid metal as the coolant. Study lead to two major variables to influence the pressure drop: fluid properties, viscosity and density, and the relative length of the posts. Correlation of the pressure drop between long and short posts and the prediction of the pressure drop of liquid metal in the pin-post mirror and comparison with an existing experiment are addressed

  16. Practical and highly sensitive elemental analysis for aqueous samples containing metal impurities employing electrodeposition on indium-tin oxide film samples and laser-induced shock wave plasma in low-pressure helium gas.

    Science.gov (United States)

    Kurniawan, Koo Hendrik; Pardede, Marincan; Hedwig, Rinda; Abdulmadjid, Syahrun Nur; Lahna, Kurnia; Idris, Nasrullah; Jobiliong, Eric; Suyanto, Hery; Suliyanti, Maria Margaretha; Tjia, May On; Lie, Tjung Jie; Lie, Zener Sukra; Kurniawan, Davy Putra; Kagawa, Kiichiro

    2015-09-01

    We have conducted an experimental study exploring the possible application of laser-induced breakdown spectroscopy (LIBS) for practical and highly sensitive detection of metal impurities in water. The spectrochemical measurements were carried out by means of a 355 nm Nd-YAG laser within N2 and He gas at atmospheric pressures as high as 2 kPa. The aqueous samples were prepared as thin films deposited on indium-tin oxide (ITO) glass by an electrolysis process. The resulting emission spectra suggest that concentrations at parts per billion levels may be achieved for a variety of metal impurities, and it is hence potentially feasible for rapid inspection of water quality in the semiconductor and pharmaceutical industries, as well as for cooling water inspection for possible leakage of radioactivity in nuclear power plants. In view of its relative simplicity, this LIBS equipment offers a practical and less costly alternative to the standard use of inductively coupled plasma-mass spectrometry (ICP-MS) for water samples, and its further potential for in situ and mobile applications.

  17. Surface cleaning of metal wire by atmospheric pressure plasma

    International Nuclear Information System (INIS)

    Nakamura, T.; Buttapeng, C.; Furuya, S.; Harada, N.

    2009-01-01

    In this study, the possible application of atmospheric pressure dielectric barrier discharge plasma for the annealing of metallic wire is examined and presented. The main purpose of the current study is to examine the surface cleaning effect for a cylindrical object by atmospheric pressure plasma. The experimental setup consists of a gas tank, plasma reactor, and power supply with control panel. The gas assists in the generation of plasma. Copper wire was used as an experimental cylindrical object. This copper wire was irradiated with the plasma, and the cleaning effect was confirmed. The result showed that it is possible to remove the tarnish which exists on the copper wire surface. The experiment reveals that atmospheric pressure plasma is usable for the surface cleaning of metal wire. However, it is necessary to examine the method for preventing oxidization of the copper wire.

  18. Photoconductivity studies of the ferrocyanide ion under high pressure

    Energy Technology Data Exchange (ETDEWEB)

    Finston, M. I.

    1979-01-01

    The photoaquation of the ferrocyanide ion was studied using a high-pressure photoconductivity apparatus and a steady-state high-pressure mercury lamp. The first-order photocurrent rise-time could be related to the relative quantum efficiency of the photoaquation process, while the dark decay of the photocurrent yielded a relative value of the bimolecular rate-constant for the reverse reaction. Kinetic measurements were carried out on dilute solutions of potassium ferrocyanide in pure water, and in 20% ethanol. The photocurrent yield in aqueous solution was dependent upon secondary chemical equilibria which were sensitive to pressure in a predictable way. In ethanolic solution, the dependence of photocurrent yield on pressure followed the variation of the reciprocal solvent vicosity. In both aqueous and alcoholic solution, the photoaquation quantum efficiency decreased exponentially with pressure, as did the biomolecular rate-constant for the dark reaction in aqueous solution. The pressure dependence of the bimolecular rate-constant in the alcoholic solution indicated a diffusion-limited process. The pressure dependence of the photoaquation quantum yield, and of the bimolecular rate-constant in aqueous solution, was interpreted in terms of an activation volume model. The photoaquation data for both the aqueous and the alcoholic solutions agreed with a hypothetical mechanism whereby ligand-to-metal bond-breaking, and solvent-to-metal bond-formation, are effectively simultaneous. The results for the aqueous dark reaction strongly indicated breaking of the solvent-to-metal bond as the rate-limiting step.

  19. 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.

  20. An unconventional metallic state in YbRh sub 2 (Si sub 1 sub - sub x Ge sub x) sub 2 - a high pressure study

    CERN Document Server

    Mederle, S; Geibel, C; Grosche, F M; Sparn, G; Trovarelli, O; Steglich, F

    2002-01-01

    We present a detailed pressure study of the electrical resistivity rho(T) and the specific heat C(T) of the non-Fermi-liquid (NFL) compound YbRh sub 2 Si sub 2 and of rho(T) for a single crystal in which 5 at.% of Si is replaced by isoelectronic Ge. The magnetic phase diagram is deduced up to p approx = 2.5 GPa. A comparison of the effects of the volume change introduced by doping and/or by hydrostatic pressure will be given. We show that the NFL behaviour observed in rho(T) as well as the magnetic phase diagram are not influenced by the disorder introduced by alloying.

  1. A study of the convective flow as a function of external parameters in a high-pressure metal halide discharge lamp (HgDyI3)

    Science.gov (United States)

    Hajji, S.; HadjSalah, S.; Benhalima, A.; Charrada, K.; Zissis, G.

    2016-06-01

    This paper deals with the modelling of the convection processes in metal-halide lamp discharges (HgDyI3). For this, we realized a 3D model, a steady, direct current powered and time-depending model for the solution of conservation equations relative to mass, momentum, and energy. After validation, this model was applied to the study of the effect of some parameters that have appeared on major transport phenomena of mass and energy in studying the lamp. Indeed, the electric current, the atomic ratio (Hg/Dy), and the effect of the convective transport have been studied.

  2. High temperature corrosion of metals

    International Nuclear Information System (INIS)

    Quadakkers, W.J.; Schuster, H.; Ennis, P.J.

    1988-08-01

    This paper covers three main topics: 1. high temperature oxidation of metals and alloys, 2. corrosion in sulfur containing environments and 3. structural changes caused by corrosion. The following 21 subjects are discussed: Influence of implanted yttrium and lanthanum on the oxidation behaviour of beta-NiA1; influence of reactive elements on the adherence and protective properties of alumina scales; problems related to the application of very fine markers in studying the mechanism of thin scale formation; oxidation behaviour of chromia forming Co-Cr-Al alloys with or without reactive element additions; growth and properties of chromia-scales on high-temperature alloys; quantification of the depletion zone in high temperature alloys after oxidation in process gas; effects of HC1 and of N2 in the oxidation of Fe-20Cr; investigation under nuclear safety aspects of Zircaloy-4 oxidation kinetics at high temperatures in air; on the sulfide corrosion of metallic materials; high temperature sulfide corrosion of Mn, Nb and Nb-Si alloys; corrosion behaviour or NiCrAl-based alloys in air and air-SO2 gas mixtures; sulfidation of cobalt at high temperatures; preoxidation for sulfidation protection; fireside corrosion and application of additives in electric utility boilers; transport properties of scales with complex defect structures; observations of whiskers and pyramids during high temperature corrosion of iron in SO2; corrosion and creep of alloy 800H under simulated coal gasification conditions; microstructural changes of HK 40 cast alloy caused by exploitation in tubes in steam reformer installation; microstructural changes during exposure in corrosive environments and their effect on mechanical properties; coatings against carburization; mathematical modeling of carbon diffusion and carbide precipitation in Ni-Cr-based alloys. (MM)

  3. 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.

  4. 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.

  5. 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)

  6. 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...

  7. High capacity hydrogen absorption in transition-metal ethylene complexes: consequences of nanoclustering

    International Nuclear Information System (INIS)

    Phillips, A B; Shivaram, B S

    2009-01-01

    We have recently shown that organo-metallic complexes formed by laser ablating transition metals in ethylene are high hydrogen absorbers at room temperature (Phillips and Shivaram 2008 Phys. Rev. Lett. 100 105505). Here we show that the absorption percentage depends strongly on the ethylene pressure. High ethylene pressures (>100 mTorr) result in a lowered hydrogen uptake. Transmission electron microscopy measurements reveal that while low pressure ablations result in metal atoms dispersed uniformly on a near atomic scale, high pressure ones yield distinct nanoparticles with electron energy-loss spectroscopy demonstrating that the metal atoms are confined solely to the nanoparticles.

  8. Band structure of CdTe under high pressure

    International Nuclear Information System (INIS)

    Jayam, Sr. Gerardin; Nirmala Louis, C.; Amalraj, A.

    2005-01-01

    The band structures and density of states of cadmium telluride (CdTe) under various pressures ranging from normal to 4.5 Mbar are obtained. The electronic band structure at normal pressure of CdTe (ZnS structure) is analyzed and the direct band gap value is found to be 1.654 eV. CdTe becomes metal and superconductor under high pressure but before that it undergoes structural phase transition from ZnS phase to NaCl phase. The equilibrium lattice constant, bulk modulus and the phase transition pressure at which the compounds undergo structural phase transition from ZnS to NaCl are predicted from the total energy calculations. The density of states at the Fermi level (N(E F )) gets enhanced after metallization, which leads to the superconductivity in CdTe. In our calculation, the metallization pressure (P M = 1.935 Mbar) and the corresponding reduced volume ((V/V 0 ) M = 0.458) are estimated. Metallization occurs via direct closing of band gap at Γ point. (author)

  9. Simulations of rapid pressure-induced solidification in molten metals

    International Nuclear Information System (INIS)

    Patel, Mehul V.; Streitz, Frederick H.

    2004-01-01

    The process of interest in this study is the solidification of a molten metal subjected to rapid pressurization. Most details about solidification occurring when the liquid-solid coexistence line is suddenly transversed along the pressure axis remain unknown. We present preliminary results from an ongoing study of this process for both simple models of metals (Cu) and more sophisticated material models (MGPT potentials for Ta). Atomistic (molecular dynamics) simulations are used to extract details such as the time and length scales that govern these processes. Starting with relatively simple potential models, we demonstrate how molecular dynamics can be used to study solidification. Local and global order parameters that aid in characterizing the phase have been identified, and the dependence of the solidification time on the phase space distance between the final (P,T) state and the coexistence line has been characterized

  10. High-pressure phase transitions - Examples of classical predictability

    Science.gov (United States)

    Celebonovic, Vladan

    1992-09-01

    The applicability of the Savic and Kasanin (1962-1967) classical theory of dense matter to laboratory experiments requiring estimates of high-pressure phase transitions was examined by determining phase transition pressures for a set of 19 chemical substances (including elements, hydrocarbons, metal oxides, and salts) for which experimental data were available. A comparison between experimental and transition points and those predicted by the Savic-Kasanin theory showed that the theory can be used for estimating values of transition pressures. The results also support conclusions obtained in previous astronomical applications of the Savic-Kasanin theory.

  11. 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.

  12. 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.

  13. Mass optimization of a small pressure vessel using metal/FRP (fiber reinforced polymers) hybrid structures

    International Nuclear Information System (INIS)

    Nisar, J.A.; Abdullah, A.N.; Iqbal, N.

    2004-01-01

    In hybrid pressure vessels, composite (Fiber) is wound over a metallic liner (Steel/Aluminum) in hoop direction. In this concept of hybrid pressure vessel structure, metallic liner takes all the axial loads and fiber reinforced polymers (FRP/sub s/) takes load in circumferential (Hoop) direction. Hybrid structures combine the relatively high shear stiffness and ductility of metal alloy with high specific stiffness, strength and fatigue properties of FRP/sub s/. The relatively simple methods for producing hybrid structures circumvent the need for the complex and expensive equipment that is used for advanced composites processing. This paper presents an efficient way of designing a hybrid pressure vessel where prime concern is weight reduction over an equivalent aluminum structure and investigates various methodologies regarding combinations of metals and FRP/sub s/ for optimization of a given pressure vessel. For this purpose we adopted two different methods of simulation one is computer simulation using ANSYS and other is experimental verification by hydrostatic testing of manufactured pressure vessel. Two different pressure vessels one with aluminum liner and other with steel liner were fabricated. Kevlar 49/epoxy was wrapped around the liners in hoop direction. Both the pressure vessels were put into hydrostatic test. Strains were measured during the test and then converted into corresponding stresses. Results of hydrostatic test were quite in favor of the ANSYS results. In this way we have successfully designed, manufactured and tested the Hybrid pressure vessel saving almost 40% weight in case of aluminum liner and 43.6% in case of steel liner. (author)

  14. Influence of deformation rate on plasticity of metals under pressure

    International Nuclear Information System (INIS)

    Churbaev, R.V.; Dobromyslov, A.V.; Kolmogorov, V.L.; Taluts, G.G.

    1990-01-01

    Change of polycrystalline molybdenum (BCC) and titanium (HCP) plasticity under pressure depeding on the deformation rate at the room temperature is studied. It is shown that the reduction of molybdenum and titanium deformation rate leads to a substantial growth of their plastic properties with the effect being increased with pressure growth. Production of several necks testifying to the transition to a superplastic state is observed at high pressures and low deformation rates. A functional dependence of plasticity change on the deformation rate under pressure is ascertained

  15. Crystallization of Pd40CU30Ni10P20 bulk metallic glass with and without pressure

    DEFF Research Database (Denmark)

    Yang, B.; Jiang, Jianzhong; Zhuang, Yanxin

    2007-01-01

    The glass-transition behavior of Pd40Cu30Ni10P20 bulk metallic glass was investigated by differential scanning calorimetry (DSC) and X-ray powder diffraction (XRD). The effect of pressure on the crystallization behavior of Pd40Cu30Ni10P20 bulk glass was studied by in situ high-pressure and high...

  16. 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 ...

  17. 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

  18. Compositions of graphene materials with metal nanostructures and microstructures and methods of making and using including pressure sensors

    KAUST Repository

    Chen, Ye

    2017-01-26

    Composition comprising at least one graphene material and at least one metal. The metal can be in the form of nanoparticles as well as microflakes, including single crystal microflakes. The metal can be intercalated in the graphene sheets. The composition has high conductivity and flexibility. The composition can be made by a one-pot synthesis in which a graphene material precursor is converted to the graphene material, and the metal precursor is converted to the metal. A reducing solvent or dispersant such as NMP can be used. Devices made from the composition include a pressure sensor which has high sensitivity. Two two- dimension materials can be combined to form a hybrid material.

  19. 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)

  20. 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...

  1. 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

  2. Reducing non value adding aluminium alloy in production of parts through high pressure die casting

    CSIR Research Space (South Africa)

    Pereira, MFVT

    2010-10-01

    Full Text Available in the cast part feed system, including overflows. CSIR intends using the results of this research for further development and application of high temperature die construction materials in high pressure die casting processes of light metal alloys...

  3. Investigation of fracture in pressurized gas metal arc welded beryllium

    International Nuclear Information System (INIS)

    Heiple, C.R.; Merlini, R.J.; Adams, R.O.

    1976-01-01

    Premature failures during proof testing of pressurized-gas-metal-arc (PGMA) welded beryllium assemblies were investigated. The failures were almost entirely within the beryllium (a forming grade, similar to HP-10 or S-240), close to and parallel to the weld interface. The aluminum-silicon weld filler metal deposit was not centered in the weld groove in the failed assemblies, and failure occurred on the side of the weld opposite the bias in the weld deposit. Tensile tests of welded samples demonstrated that the failures were unrelated to residual machining damage from cutting the weld groove, and indicated small lack-of-fusion areas near the weld start to be the most likely origin of the failures. Acoustic emission was monitored during tensile tests of the welds. The majority of acoustic emission was probably from crack propagation through the weld filler metal. Tensile bars cut from the region of the weld start behaved differently; they failed at lower loads and exhibited an acoustic emission behavior believed to be from cracking in the weld metal-beryllium interface. Improvement in the quality of these and similar beryllium welds can therefore most likely be made by centering the weld deposit and reducing the size of the weld start defect. 21 fig

  4. Microstructure characteristics of nickel reinforced metal matrix composites (Ni/AC8A) by low-pressure metal infiltration process

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Hyun Jun; Rong, Hua Wei; Jun, Ji Ang; Park, Sung Ho; Huh, Sun Chul; Park, Won Jo [Gyeongsang National University, Jinju (Korea, Republic of)

    2009-07-01

    MMCs(Metal Matrix Composites) can obtain mechanical characteristics of application purposes that a single material is difficult to obtain. Al alloy composite material that nickel is added by reinforcement is used for piston of diesel engine, because high temperature properties, strength, corrosion resistant are improved excellently than existent Al alloy. And, in case of processing, interface between Ni and Al improves wear resistant by intermetallic compound of high hardness. Also, in the world, industrial circles are proceeding research to apply excellent composite material. Existent process methods of MMC using preform were manufactured by high-pressure. But, it cause deformation of preform or fault of completed MMC. Using low-pressure as infiltration pressure can prevent this problem, and there is an advantage that is able to reduce the cost of production by small scale of production equipment. Accordingly, process methods of MMC have to consider low-pressure infiltration for the strength of preform, and nowadays, there are many studies about reducing infiltration pressure. In this study produced Al composite material that Ni is added by reinforcement by low-pressure infiltration, and observed microstructure of completed MMCs.

  5. 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.

  6. Enhanced pycnonuclear reactions in ultrahigh-pressure metals

    International Nuclear Information System (INIS)

    Ichimaru, Setsuo; Kitamura, Hikaru

    1995-01-01

    By combining the concepts of pycnonuclear reactions at low temperatures and their enhancement due to strong internuclear Coulomb correlations, we predict the possibilities of a novel scheme for fusion in ultrahigh-pressure liquid-metallic hydrogen near the freezing conditions, for the reactions 2 H(p,γ) 3 He, 3 H(d,n) 4 He, and 7 Li(p,α) 4 He. Time evolution is followed for p-d reaction after a pulsed compression with 1 kJ input and the initial conditions of mass density ≅ 20 g/cm 3 , temperature ≅ 1400 K, pressure ≅ 490 Mbar, and radius ≅ 0.017 cm; an energy yield of 33 kJ in 0.03 fs is thus predicted. (author)

  7. Superconductivity in the unconventional high pressure phase bismuth-III

    Energy Technology Data Exchange (ETDEWEB)

    Semeniuk, Konstantin; Brown, Philip; Vasiljkovic, Aleksandar; Grosche, Malte [University of Cambridge (United Kingdom)

    2015-07-01

    One of the most surprising developments in high pressure research was the realisation that many elements assume very unexpected high pressure structures, described in terms of extremely large or even infinite unit cells. Elemental bismuth, which has been known to undergo a series of pressure induced structural transitions between 25 kbar and 80 kbar, is an interesting example: the intermediate pressure Bi-III phase has a complex 'host-guest' structure consisting of two incommensurate sublattices. Since the unit cell is infinitely large, the description of electronic and lattice excitations is problematic. Apart from its metallic character and the observation of superconductivity at low temperature, little is known about the electronic structure in this phase. We investigate the electrical resistivity within the metallic Bi-III phase under high hydrostatic pressure and in applied magnetic field using a piston cylinder cell. Superconductivity is observed below 7.1 K, and we extract the temperature dependence of the upper critical field, which exceeds 2 T at low temperature. The normal state resistivity exhibits an approximately linear temperature dependence. This could be attributed to strong scattering from low-lying excitations, as caused by an unusually soft phonon spectrum. The results suggest that strong coupling superconductivity arises within the host-guest structure of Bi-III out of an unusual electronic state.

  8. Inspection of the hydrogen gas pressure with metal shield by cold neutron radiography at CMRR

    Energy Technology Data Exchange (ETDEWEB)

    Li, Hang; Cao, Chao; Huo, Heyong; Wang, Sheng; Wu, Yang; Yin, Wei; Sun, Yong; Liu, Bin; Tang, Bin [Institute of Nuclear Physics and Chemistry, Chinese Academy of Engineering Physics, Mianyang (China); Key Laboratory of Neutron Physics, Chinese Academy of Engineering Physics, Mianyang (China)

    2017-04-11

    The inspection of the process of gas pressure change is important for some applications (e.g. gas tank stockpile or two phase fluid model) which need quantitative and non-touchable measurement. Neutron radiography provides a suitable tool for such investigations with nice resolution. The quantitative cold neutron radiography (CNR) is developed at China Mianyang Research Reactor (CMRR) to measure the hydrogen gas pressure with metal shield. Because of the high sensitivity to hydrogen, even small change of the hydrogen pressure can be inspected by CNR. The dark background and scattering neutron effect are both corrected to promote measurement precision. The results show that CNR can measure the hydrogen gas pressure exactly and the pressure value average relative error between CNR and barometer is almost 1.9%.

  9. 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

  10. 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.

  11. Oxygen partial pressure: a key to alloying and discovery in metal oxide--metal eutectic systems

    International Nuclear Information System (INIS)

    Holder, J.D.; Clark, G.W.; Oliver, B.F.

    1978-01-01

    Control of oxygen partial pressure is essential in the directional solidification of oxide--metal eutectic composites by techniques involving gas-solid and gas-liquid interactions. The existence of end components in the eutectic composite is Po 2 sensitive as are melt stoichiometry, solid phase compositions, and vapor losses due to oxidation-volatilization. Simple criteria are postulated which can aid the experimentalist in selecting the proper gas mixture for oxide--metal eutectic composite growth. The Cr 2 O 3 --Mo--Cr systems was used to verify certain aspects of the proposed criteria

  12. 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...

  13. 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.

  14. 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...

  15. 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.

  16. Highly Dense Isolated Metal Atom Catalytic Sites

    DEFF Research Database (Denmark)

    Chen, Yaxin; Kasama, Takeshi; Huang, Zhiwei

    2015-01-01

    -ray diffraction. A combination of electron microscopy images with X-ray absorption spectra demonstrated that the silver atoms were anchored on five-fold oxygen-terminated cavities on the surface of the support to form highly dense isolated metal active sites, leading to excellent reactivity in catalytic oxidation......Atomically dispersed noble-metal catalysts with highly dense active sites are promising materials with which to maximise metal efficiency and to enhance catalytic performance; however, their fabrication remains challenging because metal atoms are prone to sintering, especially at a high metal...... loading. A dynamic process of formation of isolated metal atom catalytic sites on the surface of the support, which was achieved starting from silver nanoparticles by using a thermal surface-mediated diffusion method, was observed directly by using in situ electron microscopy and in situ synchrotron X...

  17. High redshift quasars and high metallicities

    Science.gov (United States)

    Ferland, Gary J.

    1997-01-01

    A large-scale code called Cloudy was designed to simulate non-equilibrium plasmas and predict their spectra. The goal was to apply it to studies of galactic and extragalactic emission line objects in order to reliably deduce abundances and luminosities. Quasars are of particular interest because they are the most luminous objects in the universe and the highest redshift objects that can be observed spectroscopically, and their emission lines can reveal the composition of the interstellar medium (ISM) of the universe when it was well under a billion years old. The lines are produced by warm (approximately 10(sup 4)K) gas with moderate to low density (n less than or equal to 10(sup 12) cm(sup -3)). Cloudy has been extended to include approximately 10(sup 4) resonance lines from the 495 possible stages of ionization of the lightest 30 elements, an extension that required several steps. The charge transfer database was expanded to complete the needed reactions between hydrogen and the first four ions and fit all reactions with a common approximation. Radiative recombination rate coefficients were derived for recombination from all closed shells, where this process should dominate. Analytical fits to Opacity Project (OP) and other recent photoionization cross sections were produced. Finally, rescaled OP oscillator strengths were used to compile a complete set of data for 5971 resonance lines. The major discovery has been that high redshift quasars have very high metallicities and there is strong evidence that the quasar phenomenon is associated with the birth of massive elliptical galaxies.

  18. 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...

  19. Determination of line broadening constants in high pressure discharge lamps

    International Nuclear Information System (INIS)

    Weiss, M; Schubert, H; Meier, S; Born, M; Reiter, D; Stroesser, M

    2005-01-01

    A numerical model of the radiative transfer in high pressure metal halide discharge lamps is used to determine line broadening parameters for atomic scandium lines. The determined broadening constants are in qualitative agreement with theoretical estimates in many cases, but significant deviations exist. The data obtained from this paper can, therefore, be used to further improve modelling of radiative contributions to the energy balance in such types of discharge lamps

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

    International Nuclear Information System (INIS)

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

    1979-01-01

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

  1. 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...

  2. 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...

  3. 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 ...

  4. 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.

  5. 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.

  6. 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.

  7. Behavior of a corium jet in high pressure melt ejection from a reactor pressure vessel

    International Nuclear Information System (INIS)

    Frid, W.

    1988-04-01

    Discharge of the molten core debris from a pressurized reactor vessel has been recognized as an important accident scenario for pressurized water reactors. Recent high-pressure melt streaming experiments conducted at Sandia National Laboratories, designed to study cavity and containment events related to melt ejection, have resulted in two important observations: (1) Expansion and breakup of the ejected molten jet. (2) Significant aerosol generation during the ejection process. The expansion and breakup of the jet in the experiments are attributed to rapid evolution of the pressurizing gas (nitrogen or hydrogen) dissolved in the melt. It has been concluded that aerosol particles may be formed by condensation of melt vapor and mechanical breakup of the melt and generation. It was also shown that the above stated phenomena are likely to occur in reactor accidents. This report provides results from analytical and experimental investigations on the behavior of a gas supersaturated molten jet expelled from a pressurized vessel. Aero-hydrodynamic stability of liquid jets in gas, stream degassing of molten metals, and gas bubble nucleation in molten metals are relevant problems that are addressed in this work

  8. 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

  9. 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...

  10. 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.

  11. A field survey of metal binding to metallothionein and other cytosolic ligands in liver of eels using an on-line isotope dilution method in combination with size exclusion (SE) high pressure liquid chromatography (HPLC) coupled to Inductively Coupled Plasma time-of-flight Mass Spectrometry (ICP-TOFMS).

    Science.gov (United States)

    Van Campenhout, Karen; Goenaga Infante, Heidi; Goemans, Geert; Belpaire, Claude; Adams, Freddy; Blust, Ronny; Bervoets, Lieven

    2008-05-15

    The effect of metal exposure on the accumulation and cytosolic speciation of metals in livers of wild populations of European eel with special emphasis on metallothioneins (MT) was studied. Four sampling sites in Flanders showing different degrees of heavy metal contamination were selected for this purpose. An on-line isotope dilution method in combination with size exclusion (SE) high pressure liquid chromatography (HPLC) coupled to Inductively Coupled Plasma time-of-flight Mass Spectrometry (ICP-TOFMS) was used to study the cytosolic speciation of the metals. The distribution of the metals Cd, Cu, Ni, Pb and Zn among cytosolic fractions displayed strong differences. The cytosolic concentration of Cd, Ni and Pb increased proportionally with the total liver levels. However, the cytosolic concentrations of Cu and Zn only increased above a certain liver tissue threshold level. Cd, Cu and Zn, but not Pb and Ni, were largely associated with the MT pool in correspondence with the environmental exposure and liver tissue concentrations. Most of the Pb and Ni and a considerable fraction of Cu and Zn, but not Cd, were associated to High Molecular Weight (HMW) fractions. The relative importance of the Cu and Zn in the HMW fraction decreased with increasing contamination levels while the MT pool became progressively more important. The close relationship between the cytosolic metal load and the total MT levels or the metals bound on the MT pool indicates that the metals, rather than other stress factors, are the major factor determining MT induction.

  12. Analysis of Pressure-Volume Relationship for Bulk Metallic Glasses

    Directory of Open Access Journals (Sweden)

    H. K. Rai

    2008-01-01

    Full Text Available Relationship between compression (V/V0 and pressure have been studied for five bulk metallic glasses (BMGs viz. Zr41Ti14Cu12.5Ni10Be22.5, Zr41Ti14Cu12.5Ni9Be22.5C1, Zr48Nb8Cu12Fe8Be24, (Zr0.59Ti0.06Cu0.22Ni0.1385.7Al14.3 and SiO2.TiO2 in the compression ranges of V/V0 =1.00 to V/V0 = 0.10. Six forms of equation of state reported in the literature have been used in the present study to calculate pressure corresponding to different values of compressions. The comparison of graph plotted between the logarithms of calculated value of pressure to logarithm of calculated value of compression (V/V0 reveals that the agreement of Brennan-Stacey equation of state (EOS and Poirier-Tarantolla equation of state are not good. It has been found that the assumptions, on which these equations are based, do not satisfy well in case of given BMGs.

  13. Influence of a hydrostatic pressure on the diffusion in metals having a cubic structure

    International Nuclear Information System (INIS)

    Beyeler, M.

    1969-01-01

    In view of obtaining informations on the structure of vacancies. We have determined, by diffusion experiments under high pressure, the activation volumes for self diffusion in different face centered cubic metals: silver, gold, copper, aluminium and in body centered cubic uranium (gamma phase). Activation volumes for noble metals diffusion in aluminium have also been investigated. The experimental results on gold, silver and copper are in good agreement with most of the theoretical models. The estimated activation volume for gamma uranium seems to indicate a vacancy mechanism.The results on aluminium for both self and impurity diffusion agree quite well with Friedel's theoretical predictions [fr

  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. Hydro mechanical deep-drawing and high pressure sheet metal forming as forming technologies for the production of complex parts made of magnesium sheet metal AZ31B-0; Hydromechanisches Tiefziehen und Hochdruckblechumformung als Verfahren zur Herstellung komplexer Bauteile aus Magnesiumfeinblechen des Typs AZ31B-0

    Energy Technology Data Exchange (ETDEWEB)

    Viehweger, B.; Richter, G.; Duering, M.; Karabet, A. [Lehrstuhlleiter, BTU Cottbus, Lehrstuhl Konstruktion und Fertigung, Konrad-Wachsmann Allee 1, 03046 Cottbus (Germany); Sviridov, A.; Hartmann, H.; Richter, U. [Forschungs- und Qualitaetszentrum Oderbruecke gGmbH Eisenhuettenstadt (Germany)

    2004-07-01

    Semi - finished sheet - metal products made of magnesium alloys such as AZ31B are known as better deformable at temperatures in the range of 175 C - 240 C. By means of hydroforming technologies, as there are hydro mechanical deep-drawing and high pressure sheet metal forming, the influence of different forming parameters on the forming results has been investigated. A more complex experimental geometry was deformed applying forming temperatures of 175 C, 200 C, 225 C and 240 C and accordingly adjusted forces of the blank holder. Concerning the applied forming - methods and experimental parameters the forming results have been evaluated and compared regarding the decrease of sheet thickness and the development of small radii. For some experimental parts, which have been deformed by means of high pressure sheet metal forming at temperatures of 175 C and 225 C, supplementary investigations have been carried out in order to determine the evolution of characteristic surface values in dependence on the forming operation. On the basis of these results practical recommendations for the limits of application of aforementioned forming technologies for AZ31B-0 magnesium sheet metal are given. (Abstract Copyright [2004], Wiley Periodicals, Inc.) [German] Eine gute Umformbarkeit von Blechhalbzeugen aus Magnesiumknetlegierungen stellt sich bekanntlich bei Anwendung von Umformtemperaturen im Bereich von 175 C - 240 C ein. Anhand der wirkmedienbasierten Umformverfahren hydromechanisches Tiefziehen und Hochdruckblechumformung ist an handelsueblichen AZ31B-0 Feinblechen die Einstellung unterschiedlicher Umformparameter erprobt worden. Unter Verwendung von Umformtemperaturen von 175 C, 200 C, 225 C und 240 C und entsprechend angepassten Niederhalterdruecken ist eine praxisnahe Versuchsgeometrie ''Minihood'' ausgeformt worden. Im Hinblick auf angewendete Umformverfahren und Versuchsparameter wurde an den Versuchsbauteilen die Blechdickenabnahme und die

  16. Influence of the reactive atmosphere on the formation of nanoparticles in the plasma plume induced by nanosecond pulsed laser irradiation of metallic targets at atmospheric pressure and high repetition rate

    Energy Technology Data Exchange (ETDEWEB)

    Girault, M. [Laboratoire Interdisciplinaire Carnot de Bourgogne, UMR 6303 CNRS-Univ. Bourgogne Franche-Comté, 9 Av. A. Savary, BP 47 870, F-21078 Dijon Cedex (France); Le Garrec, J.-L.; Mitchell, J.B.A. [Institut de Physique de Rennes, UMR 6251 CNRS-Université de Rennes 1, 35042 Rennes Cedex (France); Jouvard, J.-M. [Laboratoire Interdisciplinaire Carnot de Bourgogne, UMR 6303 CNRS-Univ. Bourgogne Franche-Comté, 9 Av. A. Savary, BP 47 870, F-21078 Dijon Cedex (France); Carvou, E. [Institut de Physique de Rennes, UMR 6251 CNRS-Université de Rennes 1, 35042 Rennes Cedex (France); Menneveux, J.; Yu, J. [Institut Lumière Matière, UMR5306 Université Lyon 1-CNRS, Université de Lyon, 69622 Villeurbanne Cedex (France); Ouf, F.-X. [Institut de Radioprotection et de Sureté Nucléaire IRSN/PSN-RES/SCA/LPMA BP 68, 91192 Gif-Sur-Yvette (France); Carles, S. [Institut de Physique de Rennes, UMR 6251 CNRS-Université de Rennes 1, 35042 Rennes Cedex (France); Potin, V.; Pillon, G.; Bourgeois, S. [Laboratoire Interdisciplinaire Carnot de Bourgogne, UMR 6303 CNRS-Univ. Bourgogne Franche-Comté, 9 Av. A. Savary, BP 47 870, F-21078 Dijon Cedex (France); Perez, J. [Synchrotron SOLEIL, L’Orme des Merisiers, Saint-Aubin, F-91192 Gif-sur-Yvette Cedex (France); Marco de Lucas, M.C., E-mail: delucas@u-bourgogne.fr [Laboratoire Interdisciplinaire Carnot de Bourgogne, UMR 6303 CNRS-Univ. Bourgogne Franche-Comté, 9 Av. A. Savary, BP 47 870, F-21078 Dijon Cedex (France); and others

    2016-06-30

    Highlights: • NPs formed in a plasma-plume during laser irradiation of metals (Al, Ti, Ag) were studied. • In situ SAXS and ex situ TEM, XRD and Raman spectra were measured. • NPs size decreased when increasing the O{sub 2} fraction in a controlled O{sub 2}+N{sub 2} atmosphere. • The oxidation of metal NPs in the plasma restricts the increase of the size of the NPs. - Abstract: The influence of a reactive atmosphere on the formation of nanoparticles (NPs) in the plasma plume generated by nanosecond pulsed laser irradiation of metal targets (Ti, Al, Ag) was probed in situ using Small Angle X-ray Scattering (SAXS). Air and different O{sub 2}–N{sub 2} gas mixtures were used as reactive gas within atmospheric pressure. SAXS results showed the formation of NPs in the plasma-plume with a mean radius varying in the 2–5 nm range. A decrease of the NPs size with increasing the O{sub 2} percentage in the O{sub 2}–N{sub 2} gas mixture was also showed. Ex situ observations by transmission electron microscopy and structural characterizations by X-ray diffraction and Raman spectroscopy were also performed for powders collected in experiments done using air as ambient gas. The stability of the different metal oxides is discussed as being a key parameter influencing the formation of NPs in the plasma-plume.

  17. Treatment of metallurgical wastes : recovery of metal values from smelter slags by pressure oxidative leaching

    Energy Technology Data Exchange (ETDEWEB)

    Li, Y.; Perederiy, I.; Papangelakis, V.G. [Toronto Univ., ON (Canada). Dept. of Chemical Engineering and Applied Chemistry

    2008-07-01

    Vast quantities of slag are produced and dumped as waste by-products during the production of base metals by smelting operations. These slags contain large amounts of valuable metals which lead to a decrease in metal yield and, combined with the entrapped sulphur, pose a danger to the environment. The dissolution of fayalite is important for the selective recovery of valuable metals and the cleanup of slags in high pressure oxidative leaching. The nature of base metals and iron in solidified slag must be investigated in order to understand the mechanism of the process. This paper discussed the application of powder X-ray diffraction (PXRD) and scanning electron microscopy (SEM) for the characterization of a smelter slag microstructure. The study used leaching tests with the same smelter slag to measure and monitor the results of leaching, including metal extraction levels, the extent of iron dissolution as well as impurity contents. The paper provided information on the experiment with particular reference to slag leaching, chemical analysis, and characterization. It was concluded that slag consists of several solid phases with base metal sulfide and oxide droplets entrapped in the fayalite matrix or silica regions. Therefore, nickel, copper, cobalt, and zinc need to be exposed either chemically or mechanically to promote their recovery. 21 refs., 4 tabs., 5 figs.

  18. 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.)

  19. Prestressed safety enclosure (PSE) with metallic cushion for new or existing reactor pressure vessels

    International Nuclear Information System (INIS)

    Wedellsborg, B.W.

    1991-01-01

    The special technology required to build the conventional types of thickwalled forged nuclear reactor pressure vessels is mastered only by a few large world-class manufactures. In order eventually to make it possible for other less established manufacturers, for example, those in newly industrialized nations, to construct nuclear RPVS or containers with large diameter for high pressures and which can tolerate large thermal gradients, an improved novel concept of a prestressed cast-iron container with multilayer shells and interlayer metallic cushions is being developed and is described in this paper. (author)

  20. Residual stress measurements in the dissimilar metal weld in pressurizer safety nozzle of nuclear power plant

    International Nuclear Information System (INIS)

    Campos, Wagner R.C.; Rabello, Emerson G.; Mansur, Tanius R.; Scaldaferri, Denis H.B.; Paula, Raphael G.; Souto, Joao P.R.S.; Carvalho Junior, Ideir T.

    2013-01-01

    Weld residual stresses have a large influence on the behavior of cracking that could possibly occur under normal operation of components. In case of an unfavorable environment, both stainless steel and nickel-based weld materials can be susceptible to stress-corrosion cracking (SCC). Stress corrosion cracks were found in dissimilar metal welds of some pressurized water reactor (PWR) nuclear plants. In the nuclear reactor primary circuit the presence of tensile residual stress and corrosive environment leads to so-called Primary Water Stress Corrosion Cracking (PWSCC). The PWSCC is a major safety concern in the nuclear power industry worldwide. PWSCC usually occurs on the inner surface of weld regions which come into contact with pressurized high temperature water coolant. However, it is very difficult to measure the residual stress on the inner surfaces of pipes or nozzles because of inaccessibility. A mock-up of weld parts of a pressurizer safety nozzle was fabricated. The mock-up was composed of three parts: an ASTM A508 C13 nozzle, an ASTM A276 F316L stainless steel safe-end, an AISI 316L stainless steel pipe and different filler metals of nickel alloy 82/182 and AISI 316L. This work presents the results of measurements of residual strain from the outer surface of the mock-up welded in base metals and filler metals by hole-drilling strain-gage method of stress relaxation. (author)

  1. 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 ...

  2. 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.

  3. Pressure-induced irreversible metallization accompanying the phase transitions in S b2S3

    Science.gov (United States)

    Dai, Lidong; Liu, Kaixiang; Li, Heping; Wu, Lei; Hu, Haiying; Zhuang, Yukai; Yang, Linfei; Pu, Chang; Liu, Pengfei

    2018-01-01

    We have revealed S b2S3 to have two phase transitions and to undergo metallization using a diamond anvil cell at around 5.0, 15.0, and 34.0 GPa, respectively. These results were obtained on the basis of high-pressure Raman spectroscopy, temperature-dependent conductivity measurements, atomic force microscopy, high-resolution transmission electron microscopy, and first-principles calculations. The first phase transition at ˜5.0 GPa is an isostructural phase transition, which is manifested in noticeable changes in five Raman-active modes and the slope of the conductivity because of a change in the electronic structure. The second pressure-induced phase transition was characterized by a discontinuous change in the slope of conductivity and a new low-intensity Raman mode at ˜15.0 GPa . Furthermore, a semiconductor-to-metal transition was found at ˜34.0 GPa , which was accompanied by irreversible metallization, and it could be attributed to the permanently plastic deformation of the interlayer spacing. This high-pressure behavior of S b2S3 will help us to understand the universal crystal structure evolution and electrical characteristics for A2B3 -type compounds, and to facilitate their application in electronic devices.

  4. 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.

  5. 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.

  6. 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

  7. 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...

  8. 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

  9. The metallic state in neutral radical conductors: dimensionality, pressure and multiple orbital effects.

    Science.gov (United States)

    Tian, Di; Winter, Stephen M; Mailman, Aaron; Wong, Joanne W L; Yong, Wenjun; Yamaguchi, Hiroshi; Jia, Yating; Tse, John S; Desgreniers, Serge; Secco, Richard A; Julian, Stephen R; Jin, Changqing; Mito, Masaki; Ohishi, Yasuo; Oakley, Richard T

    2015-11-11

    Pressure-induced changes in the solid-state structures and transport properties of three oxobenzene-bridged bisdithiazolyl radicals 2 (R = H, F, Ph) over the range 0-15 GPa are described. All three materials experience compression of their π-stacked architecture, be it (i) 1D ABABAB π-stack (R = Ph), (ii) quasi-1D slipped π-stack (R = H), or (iii) 2D brick-wall π-stack (R = F). While R = H undergoes two structural phase transitions, neither of R = F, Ph display any phase change. All three radicals order as spin-canted antiferromagnets, but spin-canted ordering is lost at pressures pressure, and the thermal activation energy for conduction Eact is eliminated at pressures ranging from ∼3 GPa for R = F to ∼12 GPa for R = Ph, heralding formation of a highly correlated (or bad) metallic state. For R = F, H the pressure-induced Mott insulator to metal conversion has been tracked by measurements of optical conductivity at ambient temperature and electrical resistivity at low temperature. For R = F compression to 6.2 GPa leads to a quasiquadratic temperature dependence of the resistivity over the range 5-300 K, consistent with formation of a 2D Fermi liquid state. DFT band structure calculations suggest that the ease of metallization of these radicals can be ascribed to their multiorbital character. Mixing and overlap of SOMO- and LUMO-based bands affords an increased kinetic energy stabilization of the metallic state relative to a single SOMO-based band system.

  10. 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

  11. High temperature equation of state of metallic hydrogen

    International Nuclear Information System (INIS)

    Shvets, V. T.

    2007-01-01

    The equation of state of liquid metallic hydrogen is solved numerically. Investigations are carried out at temperatures from 3000 to 20 000 K and densities from 0.2 to 3 mol/cm 3 , which correspond both to the experimental conditions under which metallic hydrogen is produced on earth and the conditions in the cores of giant planets of the solar system such as Jupiter and Saturn. It is assumed that hydrogen is in an atomic state and all its electrons are collectivized. Perturbation theory in the electron-proton interaction is applied to determine the thermodynamic potentials of metallic hydrogen. The electron subsystem is considered in the randomphase approximation with regard to the exchange interaction and the correlation of electrons in the local-field approximation. The proton-proton interaction is taken into account in the hard-spheres approximation. The thermodynamic characteristics of metallic hydrogen are calculated with regard to the zero-, second-, and third-order perturbation theory terms. The third-order term proves to be rather essential at moderately high temperatures and densities, although it is much smaller than the second-order term. The thermodynamic potentials of metallic hydrogen are monotonically increasing functions of density and temperature. The values of pressure for the temperatures and pressures that are characteristic of the conditions under which metallic hydrogen is produced on earth coincide with the corresponding values reported by the discoverers of metallic hydrogen to a high degree of accuracy. The temperature and density ranges are found in which there exists a liquid phase of metallic hydrogen

  12. 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

  13. Micro-hydromechanical deep drawing of metal cups with hydraulic pressure effects

    Science.gov (United States)

    Luo, Liang; Jiang, Zhengyi; Wei, Dongbin; Wang, Xiaogang; Zhou, Cunlong; Huang, Qingxue

    2018-03-01

    Micro-metal products have recently enjoyed high demand. In addition, metal microforming has drawn increasing attention due to its net-forming capability, batch manufacturing potential, high product quality, and relatively low equipment cost. Micro-hydromechanical deep drawing (MHDD), a typical microforming method, has been developed to take advantage of hydraulic force. With reduced dimensions, the hydraulic pressure development changes; accordingly, the lubrication condition changes from the macroscale to the microscale. A Voronoi-based finite element model is proposed in this paper to consider the change in lubrication in MHDD according to open and closed lubricant pocket theory. Simulation results agree with experimental results concerning drawing force. Changes in friction significantly affect the drawing process and the drawn cups. Moreover, defined wrinkle indexes have been shown to have a complex relationship with hydraulic pressure. High hydraulic pressure can increase the maximum drawing ratio (drawn cup height), whereas the surface finish represented by the wear is not linearly dependent on the hydraulic pressure due to the wrinkles.

  14. Analysis of Pressure Variations in a Low-Pressure Nickel-Hydrogen Battery- Part 2: Cells with Metal Hydride Storage.

    Science.gov (United States)

    Purushothaman, B K; Wainright, J S

    2012-05-15

    A sub-atmospheric pressure nickel hydrogen (Ni-H(2)) battery with metal hydride for hydrogen storage is developed for implantable neuroprosthetic devices. Pressure variations during charge and discharge of the cell are analyzed at different states of charge and are found to follow the desorption curve of the pressure composition isotherm (PCI) of the metal hydride. The measured pressure agreed well with the calculated theoretical pressure based on the PCI and is used to predict the state of charge of the battery. Hydrogen equilibration with the metal hydride during charge/discharge cycling is fast when the pressure is in the range from 8 to 13 psia and slower in the range from 6 to 8 psia. The time constant for the slower hydrogen equilibration, 1.37h, is similar to the time constant for oxygen recombination and therefore pressure changes due to different mechanisms are difficult to estimate. The self-discharge rate of the cell with metal hydride is two times lower in comparison to the cell with gaseous hydrogen storage alone and is a result of the lower pressure in the cell when the metal hydride is used.

  15. Analysis of Pressure Variations in a Low-Pressure Nickel-Hydrogen Battery– Part 2: Cells with Metal Hydride Storage

    Science.gov (United States)

    Purushothaman, B. K.; Wainright, J. S.

    2012-01-01

    A sub-atmospheric pressure nickel hydrogen (Ni-H2) battery with metal hydride for hydrogen storage is developed for implantable neuroprosthetic devices. Pressure variations during charge and discharge of the cell are analyzed at different states of charge and are found to follow the desorption curve of the pressure composition isotherm (PCI) of the metal hydride. The measured pressure agreed well with the calculated theoretical pressure based on the PCI and is used to predict the state of charge of the battery. Hydrogen equilibration with the metal hydride during charge/discharge cycling is fast when the pressure is in the range from 8 to 13 psia and slower in the range from 6 to 8 psia. The time constant for the slower hydrogen equilibration, 1.37h, is similar to the time constant for oxygen recombination and therefore pressure changes due to different mechanisms are difficult to estimate. The self-discharge rate of the cell with metal hydride is two times lower in comparison to the cell with gaseous hydrogen storage alone and is a result of the lower pressure in the cell when the metal hydride is used. PMID:22711974

  16. 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

  17. 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.

  18. 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.

  19. 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.

  20. 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.

  1. 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

  2. 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.

  3. 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

  4. 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.

  5. High-performance fiber/epoxy composite pressure vessels

    Science.gov (United States)

    Chiao, T. T.; Hamstad, M. A.; Jessop, E. S.; Toland, R. H.

    1978-01-01

    Activities described include: (1) determining the applicability of an ultrahigh-strength graphite fiber to composite pressure vessels; (2) defining the fatigue performance of thin-titanium-lined, high-strength graphite/epoxy pressure vessel; (3) selecting epoxy resin systems suitable for filament winding; (4) studying the fatigue life potential of Kevlar 49/epoxy pressure vessels; and (5) developing polymer liners for composite pressure vessels. Kevlar 49/epoxy and graphite fiber/epoxy pressure vessels, 10.2 cm in diameter, some with aluminum liners and some with alternation layers of rubber and polymer were fabricated. To determine liner performance, vessels were subjected to gas permeation tests, fatigue cycling, and burst tests, measuring composite performance, fatigue life, and leak rates. Both the metal and the rubber/polymer liner performed well. Proportionately larger pressure vessels (20.3 and 38 cm in diameter) were made and subjected to the same tests. In these larger vessels, line leakage problems with both liners developed the causes of the leaks were identified and some solutions to such liner problems are recommended.

  6. 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.

  7. 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

  8. 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...

  9. 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.

  10. 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.

  11. 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)

  12. 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

  13. 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

  14. 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

  15. High Pressure and High Temperature State of Oxygen Enriched Ice

    Science.gov (United States)

    LI, M.; Zhang, S.; Jeanloz, R.; Militzer, B.

    2016-12-01

    Interior models for Uranus and Neptune include a hydrogen/helium/water outer envelope and a core of rock and metal at the center, with superionic water-rich ice proposed as comprising an intermediate layer. Here we consider an oxygen-enriched ice, such as H2O2 hydrogen peroxide (± water), that could form through chemical reaction between water-rich and underlying rocky (i.e., oxygen-rich) layers. As oxygen and its compounds (e.g., H2O, SiO2) form metallic fluids at pressures above 100-150 GPa, the problem amounts to considering oxygen alloying of semiconducting or metallic water. The density of H2O2 is 1.45 g/cc at ambient pressure and 0° C, increasing to 1.71 g/cc in the solid state at about -20° C. There are no Hugoniot data beyond 30 GPa, so we estimated Hugoniots for H2O2 with different initial densities, using both a mixing model based on Hugoniot data for H2O2 and 1/2 O2 (molar volume summation under pressure) and ab initio calculations for unreacted H2O2. The results agree with each other to pressures of about 200 GPa, and the ab initio calculations show evidence of a superionic state at temperatures as low as 500 K, much lower than for water ice. Hydrogen peroxide is expected to be liquid along planetary isentropes for Uranus and Neptune, suggesting that H2O2 may not be present as a pure compound in these planets. Instead, oxygen-enriched H2O ice may be the relevant form of water and oxygen, and might be produced in the laboratory by way of dynamic compression of H2O2 or laser-heating of statically compressed H2O + O2 and/or H2O2.

  16. Luminescent decay and spectra of impurity-activated alkali halides under high pressure

    International Nuclear Information System (INIS)

    Klick, D.I.

    1977-01-01

    The effect of high pressure on the luminescence of alkali halides doped with the transition-metal ions Cu + and Ag + and the heavy-metal ions In + and Tl + was investigated to 140 kbar. Measurement of spectra allowed the prediction of kinetic properties, and the predictions agree with lifetime data

  17. 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

  18. 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.

  19. 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

  20. 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.

  1. High-pressure electron-resonance studies of electronic, magnetic, and structural phase transitions. Progress report

    International Nuclear Information System (INIS)

    Pifer, J.H.; Croft, M.C.

    1983-01-01

    Research is described in development of a high-pressure electron-resonance probe capable of operating down to 1.5 0 K temperatures. The apparatus has been used to measure the EPR of a sample of DPPH at room temperature and zero pressure. EPR has been used to measure valence field instabilities in alloy systems. Studies have been done on metal-insulator transitions at high pressure, and are briefly described

  2. 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...

  3. 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....

  4. High pressure Moessbauer spectrometer for the high-resolution 93.3 keV resonance in 67Zn

    International Nuclear Information System (INIS)

    Adlassnig, W.; Potzel, W.; Moser, J.; Schaefer, C.; Steiner, M.; Kalvius, G.M.

    1989-01-01

    A high pressure, low temperature Moessbauer spectrometer for the high-resolution 93.3 keV resonance in 67 Zn is described. The pressure is generated by applying the opposed anvil technique. Using B 4 C anvils and a sandwich gasket quasihydrostatic pressures up to 6 GPa were obtained for the required large samples of 7 mm diameter and 2 mm thickness. The piezoelectric Doppler drive is mounted on top of the pressure clamp. The whole system can be cooled to liquid He temperatures. The spectrometer was used to investigate at 4.2 K the pressure dependence of the Moessbauer parameters of Zn metal. (orig.)

  5. Fabrication techniques of metal liner used for pressure vessels made by composite material

    International Nuclear Information System (INIS)

    Takahashi, W.K.; Al-Qureshi, H.A.

    1982-01-01

    Different viable techniques for the manufacturing of metal liner used for pressure vessels are presented. The aim of these metal liner is to avoid the fluid leakage from the pressurized vessel and to serve as a mandreal to be wound by composite material. The studied techniques are described and the practical results are illustrated. Finally a comparative study of the manufacturing techniques is made in order to define the process that furnishes the metal liner with the best characteristics. The advantages offered by these type of pressure vessels when compared with the conventional metallic vessels, are also presented. (Author) [pt

  6. INVESTIGATION OF MATERIAL RESISTANCE TO PLASTIC DEFORMATION AT PROCESSING METALS BY PRESSURE WITH IMPOSING ULTRASONIC OSCILLATIONS

    Directory of Open Access Journals (Sweden)

    V. V. Klubovich

    2007-01-01

    Full Text Available The paper contains substantiation for application of experimental technique in order to investigate material resistance to plastic deformation at processing metals by pressure with imposing ultrasonic oscillations while proceeding from laws of similarity. It is shown that at modeling any metal processing by pressure with imposing ultrasonic oscillations it is possible to consider that actual elastic and plastic metal properties remain constant during processing under ultrasound action. The second aspect that requires a special attention at modeling is pulse or vibration-shock deformation at processing metals by pressure with imposing ultrasonic oscillations.

  7. 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.

  8. 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.

  9. 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.

  10. 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...

  11. In situ X-ray diffraction environments for high-pressure reactions

    DEFF Research Database (Denmark)

    R. S. Hansen, Bjarne; Møller, Kasper Trans; Paskevicius, Mark

    2015-01-01

    ), quartz glass (SiO2), stainless steel (S316) and glassy carbon (Sigradur K), and burst pressures are calculated and tested for the different tube materials. In these studies, high hydrogen pressure is generated with a metal hydride hydrogen compressor mounted in a closed system, which allows reuse...

  12. Versatile high current metal ion implantation facility

    International Nuclear Information System (INIS)

    Brown, I.G.; Dickinson, M.R.; Galvin, J.E.; Godechot, X.; MacGill, R.A.

    1992-01-01

    A metal ion implantation facility has been developed with which high current beams of practically all the solid metals of the periodic table can be produced. A multicathode, broad-beam, metal vapor vacuum arc ion source is used to produce repetitively pulsed metal ion beams at an extraction voltage of up to 100 kV, corresponding to an ion energy of up to several hundred kiloelectronvolts because of the ion charge state multiplicity, and with a beam current of up to several amps peak pulsed and several tens of milliamps time averaged delivered onto a downstream target. Implantation is done in a broad-beam mode, with a direct line of sight from ion source to target. Here we summarize some of the features of the ion source and the implantation facility that has been built up around it. (orig)

  13. Metal recovery from high-grade WEEE

    DEFF Research Database (Denmark)

    Bigum, Marianne; Brogaard, Line Kai-Sørensen; Christensen, Thomas Højlund

    2012-01-01

    . The modeled metallurgical treatment facility included a Kaldo plant, a converter aisle, an anode refinery and a precious metal refinery. The metallurgic treatment showed significant environmental savings when credited the environmental load from avoided production of the same amount of metals by mining...... and refining of ore. The resource recovery per tonne of high-grade WEEE ranged from 2 g of palladium to 386 kg of iron. Quantified in terms of person-equivalents the recovery of palladium, gold, silver, nickel and copper constituted the major environmental benefit of the recovery of metals from WEEE....... These benefits are most likely underestimated in the model, since we did not find adequate data to include all the burdens from mining and refining of ore; burdens that are avoided when metals are recovered from WEEE. The processes connected to the pre-treatment of WEEE were found to have little environmental...

  14. Pulsed high energy synthesis of fine metal powders

    Science.gov (United States)

    Witherspoon, F. Douglas (Inventor); Massey, Dennis W. (Inventor)

    1999-01-01

    Repetitively pulsed plasma jets generated by a capillary arc discharge at high stagnation pressure (>15,000 psi) and high temperature (>10,000 K) are utilized to produce 0.1-10 .mu.m sized metal powders and decrease cost of production. The plasma jets impact and atomize melt materials to form the fine powders. The melt can originate from a conventional melt stream or from a pulsed arc between two electrodes. Gas streams used in conventional gas atomization are replaced with much higher momentum flux plasma jets. Delivering strong incident shocks aids in primary disintegration of the molten material. A series of short duration, high pressure plasma pulses fragment the molten material. The pulses introduce sharp velocity gradients in the molten material which disintegrates into fine particles. The plasma pulses have peak pressures of approximately one kilobar. The high pressures improve the efficiency of disintegration. High gas flow velocities and pressures are achieved without reduction in gas density. Repetitively pulsed plasma jets will produce powders with lower mean size and narrower size distribution than conventional atomization techniques.

  15. High performance sinter-HIP for hard metals

    International Nuclear Information System (INIS)

    Hongxia Chen; Deming Zhang; Yang Li; Jingping Chen

    2001-01-01

    The horizontal sinter-HIP equipment with great charge capacity and high performance, developed and manufactured by Central Iron and Steel Research Institute(CISRI), is mainly used for sintering and condensation of hard metals. This equipment is characterized by large hot zone, high heating speed, good temperature uniformity and fast cooling system. The equipment can provide uniform hot zone with temperature difference less than 6 o C at 1500-1600 o C and 6-10 MPa by controlling temperature, pressure and circulation of gas precisely. Using large scale horizontal sinter-HIP equipment to produce hard matals have many advantages such as stable quality, high efficiency of production, high rate of finished products and low production cost, so this equipment is a good choice for manufacturer of hard metals. (author)

  16. High efficiency particulate removal with sintered metal filters

    International Nuclear Information System (INIS)

    Kirstein, B.E.; Paplawsky, W.J.; Pence, D.T.; Hedahl, T.G.

    1981-01-01

    Because of their particle removal efficiencies and durability, sintered metal filters have been chosen for high efficiency particulate air (HEPA) filter protection in the off-gas treatment system for the proposed Idaho National Engineering Laboratory Transuranic Waste Treatment Facility. Process evaluation of sintered metal filters indicated a lack of sufficient process design data to ensure trouble-free operation. Subsequence pilot scale testing was performed with flyash as the test particulate. The test results showed that the sintered metal filters can have an efficiency greater than 0.9999999 for the specific test conditions used. Stable pressure drop characteristics were observed in pulsed and reversed flow blowback modes of operation. Over 4900 hours of operation were obtained with operating conditions ranging up to approximately 90 0 C and 24 vol % water vapor in the gas stream

  17. Design criteria for high-temperature-affected, metallic and ceramic components, and for the prestressed concrete reactor pressure vessel of future HTR systems. Final report. Vol. 1-4

    International Nuclear Information System (INIS)

    1988-08-01

    This work in five separate volumes reports on the elaboration of basic data for the formulation of design criteria for HTR components and is arranged into the four following subject areas : (1) safety-specific limiting conditions; (2) metallic components; (3) prestressed concrete reactor pressure vessels; (4) graphitic reactor internals. Under item 2, the mechanical and physical characteristics of the materials X20CrMoV 12 1, X10NiCrAlTi 32 20, and NiCr23Co12Mo are examined up to temperatures of 950deg C. Stress-strain rate laws are elaborated for description of the inelastic deformation behavior. The representation of the subject area reactor pressure vessels deals with four main topics: Prestressed concrete support structure, liner, vessel closures, thermal protection system. Quality-assurance classes are defined under item 4 for graphitic components and load levels for load categories. The material evaluation is discussed in detail (e.g. manufacturing monitoring from the raw material to the graphitization and manufacturing testing up to the acceptance test). In addition, the corrosion behavior and irradiation behavior of graphite is examined and rules for computation of stresses in irradiated and unirradiated graphitic components are elaborated. (MM) [de

  18. 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)

  19. 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.

  20. 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

  1. 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....

  2. Effect of oxygen partial pressure on oxidation of Mo-metal

    Science.gov (United States)

    Sharma, Rabindar Kumar; Kumar, Prabhat; Singh, Megha; Gopal, Pawar; Reddy, G. B.

    2018-05-01

    This report explains the effect of oxygen partial pressure (PO2 ) on oxidation of Mo-metal in oxygen plasma. XRD results indulge that oxide layers formed on Mo-surfaces at different oxygen partial pressures have two different oxide phases (i.e. orthorhombic MoO3 and monoclinic Mo8O23). Intense XRD peaks at high pressure (i.e. 2.0×10-1 Torr) points out the formation of thick oxide layer on Mo-surface due to presence of large oxygen species in chamber and less oxide volatilization. Whereas, at low PO2 (6.5×10-2 and 7.5×10-2 Torr.) the reduced peak strength is owing to high oxide volatilization rate. SEM micrographs and thickness measurements also support XRD results and confirm that the optimum -2value of PO2 to deposited thicker and uniform oxide film on glass substrate is 7.5×10-2 Torr through plasma assistedoxidation process. Further to study the compositional properties, EDX of the sample M2 (the best sample) is carried out, which confirms that the stoichiometric ratio is less than 3 (i.e. 2.88). Less stoichiometric ratio again confirms the presence of sub oxides in oxide layers on Mo metal as evidenced by XRD results. All the observed results are well in consonance with each other.

  3. 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.

  4. Pressure effect on crystallization of metallic glass Fe72P11C6Al5B4Ga2 alloy with wide supercooled liquid region

    DEFF Research Database (Denmark)

    Jiang, Jianzhong; Olsen, J. S.; Gerward, Leif

    2000-01-01

    The effect of pressure on the crystallization behavior of metallic glass Fe72P11C6Al5B4Ga2 alloy with a wide supercooled liquid region has been investigated by in situ high-pressure and high-temperature x-ray diffraction measurements using synchrotron radiation. In the pressure range from 0 to 2...... mobility and changes of the Gibbs free energy of various phases with pressure. ©2000 American Institute of Physics....

  5. 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

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

    International Nuclear Information System (INIS)

    Latorre, V.R.

    1991-01-01

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

  7. 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

  8. Significant enhancement of thermoelectric properties and metallization of Al-doped Mg2Si under pressure

    International Nuclear Information System (INIS)

    Morozova, Natalia V.; Korobeinikov, Igor V.; Karkin, Alexander E.; Shchennikov, Vladimir V.; Ovsyannikov, Sergey V.; Takarabe, Ken-ichi; Mori, Yoshihisa; Nakamura, Shigeyuki

    2014-01-01

    We report results of investigations of electronic transport properties and lattice dynamics of Al-doped magnesium silicide (Mg 2 Si) thermoelectrics at ambient and high pressures to and beyond 15 GPa. High-quality samples of Mg 2 Si doped with 1 at. % of Al were prepared by spark plasma sintering technique. The samples were extensively examined at ambient pressure conditions by X-ray diffraction studies, Raman spectroscopy, electrical resistivity, magnetoresistance, Hall effect, thermoelectric power (Seebeck effect), and thermal conductivity. A Kondo-like feature in the electrical resistivity curves at low temperatures indicates a possible magnetism in the samples. The absolute values of the thermopower and electrical resistivity, and Raman spectra intensity of Mg 2 Si:Al dramatically diminished upon room-temperature compression. The calculated thermoelectric power factor of Mg 2 Si:Al raised with pressure to 2–3 GPa peaking in the maximum the values as high as about 8 × 10 −3 W/(K 2 m) and then gradually decreased with further compression. Raman spectroscopy studies indicated the crossovers near ∼5–7 and ∼11–12 GPa that are likely related to phase transitions. The data gathered suggest that Mg 2 Si:Al is metallized under moderate pressures between ∼5 and 12 GPa.

  9. 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)

  10. 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...

  11. 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.)

  12. 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

  13. 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

  14. Anomalies of ultrasound attenuation in metals under hydrostatic pressure

    International Nuclear Information System (INIS)

    Galkin, A.A.; Datsko, O.I.; Varyukhin, V.N.; Pilipenko, N.P.

    1978-01-01

    Ultrasonic attenuation was measured in polycrystal specimens of molybdenum, chromium and zinc under hydrostatic pressure up to 6 kbar. On the plot of ultrasound attenuation dependence on the pressure in molybdenum the maxima are observed under the pressure of 2 kbar. The anomaly of ultrasound attenuation is shown to connect only with brittle-ductile transtion

  15. 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...

  16. 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.

  17. Storage of hydrogen in advanced high pressure container. Appendices

    International Nuclear Information System (INIS)

    Bentzen, J.J.; Lystrup, A.

    2005-07-01

    The objective of the project has been to study barriers for a production of advanced high pressure containers especially suitable for hydrogen, in order to create a basis for a container production in Denmark. The project has primarily focused on future Danish need for hydrogen storage in the MWh area. One task has been to examine requirement specifications for pressure tanks that can be expected in connection with these stores. Six potential storage needs have been identified: (1) Buffer in connection with start-up/regulation on the power grid. (2) Hydrogen and oxygen production. (3) Buffer store in connection with VEnzin vision. (4) Storage tanks on hydrogen filling stations. (5) Hydrogen for the transport sector from 1 TWh surplus power. (6) Tanker transport of hydrogen. Requirements for pressure containers for the above mentioned use have been examined. The connection between stored energy amount, pressure and volume compared to liquid hydrogen and oil has been stated in tables. As starting point for production technological considerations and economic calculations of various container concepts, an estimation of laminate thickness in glass-fibre reinforced containers with different diameters and design print has been made, for a 'pure' fibre composite container and a metal/fibre composite container respectively. (BA)

  18. Study on uranium metallization yield of spent Pressurized Water Reactor fuels and oxidation behavior of fission products in uranium metals

    International Nuclear Information System (INIS)

    Choi, Ke Chon; Lee, Chang Heon; Kim, Won Ho

    2003-01-01

    Metallization yield of uranium oxide to uranium metal from lithium reduction process of spent Pressurized Water Reactor (PWR) fuels was measured using thermogravimetric analyzer. A reduced metal produced in the process was divided into a solid and a powder part, and each metallization yield was measured. Metallization yield of the solid part was 90.7∼95.9 wt%, and the powder being 77.8∼71.5 wt% individually. Oxidation behaviour of the quarternary alloy was investigated to take data on the thermal oxidation stability necessary for the study on dry storage of the reduced metal. At 600∼700 .deg. C, weight increments of allow of No, Ru, Rh and Pd was 0.40∼0.55 wt%. Phase change on the surface of the allow was started at 750 .deg. C. In particular, Mo was rapidly oxidized and then the alloy lost 0.76∼25.22 wt% in weight

  19. 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...

  20. 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.

  1. 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

  2. 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.

  3. Isolation of high purity americium metal via distillation

    Science.gov (United States)

    Squires, Leah N.; King, James A.; Fielding, Randall S.; Lessing, Paul

    2018-03-01

    Pure americium metal is a crucial component for the fabrication of transmutation fuels. Unfortunately, americium in pure metal form is not available; however, a number of mixed metals and mixed oxides that include americium are available. In this manuscript a method is described to obtain high purity americium metal from a mixture of americium and neptunium metals with lead impurity via distillation.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1994-05-01

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

  5. 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.

  6. 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.

  7. Pressure-driven insulator-metal transition in cubic phase UO2

    Science.gov (United States)

    Huang, Li; Wang, Yilin; Werner, Philipp

    2017-09-01

    Understanding the electronic properties of actinide oxides under pressure poses a great challenge for experimental and theoretical studies. Here, we investigate the electronic structure of cubic phase uranium dioxide at different volumes using a combination of density functional theory and dynamical mean-field theory. The ab initio calculations predict an orbital-selective insulator-metal transition at a moderate pressure of ∼45 GPa. At this pressure the uranium's 5f 5/2 state becomes metallic, while the 5f 7/2 state remains insulating up to about 60 GPa. In the metallic state, we observe a rapid decrease of the 5f occupation and total angular momentum with pressure. Simultaneously, the so-called “Zhang-Rice state”, which is of predominantly 5f 5/2 character, quickly disappears after the transition into the metallic phase.

  8. 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.

  9. High Re-Operation Rates Using Conserve Metal-On-Metal Total Hip Articulations

    DEFF Research Database (Denmark)

    Mogensen, S L; Jakobsen, Thomas; Christoffersen, Hardy

    2016-01-01

    INTRODUCTION: Metal-on-metal hip articulations have been intensely debated after reports of adverse reactions and high failure rates. The aim of this study was to retrospectively evaluate the implant of a metal-on.metal total hip articulation (MOM THA) from a single manufacture in a two-center st......INTRODUCTION: Metal-on-metal hip articulations have been intensely debated after reports of adverse reactions and high failure rates. The aim of this study was to retrospectively evaluate the implant of a metal-on.metal total hip articulation (MOM THA) from a single manufacture in a two...

  10. 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).

  11. Metallic Membranes for High Temperature Hydrogen Separation

    DEFF Research Database (Denmark)

    Ma, Y.H.; Catalano, Jacopo; Guazzone, Federico

    2013-01-01

    membrane fabrication methods have matured over the last decades, and the deposition of very thin films (1–5 µm) of Pd over porous ceramics or modified porous metal supports is quite common. The H2 permeances and the selectivities achieved at 400–500 °C were in the order of 50–100 Nm3/m/h/bar0.5 and greater......Composite palladium membranes have extensively been studied in laboratories and, more recently, in small pilot industrial applications for the high temperature separation of hydrogen from reactant mixtures such as water-gas shift (WGS) reaction or methane steam reforming (MSR). Composite Pd...... than 1000, respectively. This chapter describes in detail composite Pd-based membrane preparation methods, which consist of the grading of the support and the deposition of the dense metal layer, their performances, and their applications in catalytic membrane reactors (CMRs) at high temperatures (400...

  12. Refractiry metal monocrystals in high temperature thermometry

    International Nuclear Information System (INIS)

    Kuritnyk, I.P.

    1988-01-01

    The regularities of changes in thermoelectric properties of refractory metals in a wide temperature range (300-2300 K) depending on their structural state and impurities, are generalized. It is found that the main reasons for changes in thermo-e.m.f. of refractory metals during their operation in various media are diffusion processes and local microvoltages appearing in nonhomogeneous thermoelectrodes. It is shown that microstructure formation and control of impurities in thermometric materials permit to improve considerably the metrologic parameters of thermal transformers. Tungsten and molybdenum with monocrystalline structure with their high stability of properties, easy to manufacture and opening new possibilities in high-temperature contact measurement are used in thermometry for the first time

  13. 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.

  14. Superconductivity in hydrogen-rich materials at high pressures

    Energy Technology Data Exchange (ETDEWEB)

    Drozdov, Alexander

    2016-07-01

    A room temperature superconductor is probably one of the most desired systems in solid state physics. The highest critical temperature (T{sub c}) that has been achieved so far is in the copper oxide system: 133 kelvin (K) at ambient pressure ([82]Schilling et al. 1993) and 160 K under pressure ([42]Gao et al. 1994). The nature of superconductivity in the cuprates and in the recently discovered iron-based superconductor family (T{sub c}=57 K) is still not fully understood. In contrast, there is a class of superconductors which is well-described by the Bardeen, Cooper, Schrieffer (BCS) theory - conventional superconductors. Great efforts were spent in searching for high-temperature (T{sub c} > 77 K) conventional superconductor but only T{sub c} = 39 K has been reached in MgB2 ([68]Nagamatsu et al. 2001). BCS theory puts no bounds for T{sub c} as follows from Eliashberg's formulation of BCS theory. T{sub c} can be high, if there is a favorable combination of high-frequency phonons, strong electron-phonon coupling, and a high density of states. It does not predict however in which materials all three parameters are large. At least it gives a clear indication that materials with light elements are favorable as light elements provide high frequencies in the phonon spectrum. The lightest element is hydrogen, and Ashcroft made a first prediction that metallic hydrogen will be a high-temperature superconductor ([6]Ashcroft 1968). As pressure of hydrogen metallization was too high (about 400-500 GPa) for experimental techniques then he proposed that compounds dominated by hydrogen (hydrides) also might be good high temperature superconductors ([6]Ashcroft 1968; [7]Ashcroft 2004). A lot of the followed calculations supported this idea. T{sub c} in the range of 50-235 kelvin was predicted for many hydrides. Unfortunately, only a moderate T{sub c} of 17 kelvin has been observed experimentally ([27]Eremets et al. 2008) so far. A goal of the present work is to find a

  15. 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.

  16. Metal extrusion using hydrostatic pressures; Le filage des metaux sous pression hydrostatique

    Energy Technology Data Exchange (ETDEWEB)

    Sauve, Ch [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1965-07-01

    The main problems connected with the deformation of metals due to extrusion are described. A method is put forward for calculating the rational rate of percentage deformation in the case of bar extrusion using a cylindrical container; reference is made to previous work on extrusion using a hydrostatic pressure with or without back-pressure. An extrusion process is described using hydrostatic pressure, without back-pressure, and using the lubricant for transmitting the thrust. This process has been used for eight years by the C.E.A. for the extrusion of a very wide range of metals, from beryllium to uranium and including steels; it leads to excellent surface textures. A very fine crystallization can be obtained on extruded products when the rate of extrusion is very low. There appears to be nothing against the use of high extrusion rates using this method. (author) [French] On expose les problemes generaux lies a la deformation des metaux par filage. On propose un calcul de la vitesse rationnelle de deformation pour cent dans le cas du filage de barres a partir d'un conteneur cylindrique, et l'on cite les travaux anterieurs sur le filage par faction d'une pression hydrostatique sans ou avec une contre-pression. On decrit un procede de filage par l'action d'une pression hydrostatique, sans contre-pression, utilisant le lubrifiant pour transmettre la poussee. Ce procede employe depuis 8 ans au C.E.A. pour filer les metaux les plus divers, depuis le beryllium jusqu'a l'uranium en passant par les aciers, permet d'obtenir d'excellents etats de surface. Une cristallisation tres fine peut etre obtenue sur les produits files lorsque le filage est tres lent. Rien ne parait s'opposer a ce que des filages rapides soient effectues avec cette methode. (auteur)

  17. Development of a metallic high integrity container

    International Nuclear Information System (INIS)

    Haelsig, R.T.

    1986-01-01

    Nuclear Packaging, a Pacific Nuclear Company, developed a metallic high integrity container (HIC) for the burial of low level radioactive waste. This class of container has received the most extensive review of any burial container licensed in the United States. It is also the first container that has been licensed to meet the requirements of Nuclear Regulatory Commission Regulations 10CFR61. The design and subsequent review considered 300 years corrosion at a depth of 55 feet with no degradation of container structural integrity. The design also included a technical requirement that the container possess a positive vent that would exclude moisture. The alloy that was selected, allows for significant flexibility in container size and configuration which is essential to accommodating the various waste forms. This allowed the development of containers in various sizes and with a variety of closures, that accommodate the internal dimensions of various shipping shields and help minimize radiation exposure during packaging operations. The material used in the metallic container is high corrosion resistant which reduces the need for strict chemical controls at the waste generating facility. This acts to ease the operational requirements in the treatment of several waste streams. The design result is a family of metallic High Integrity Containers (HIC)s that meet all the performance criteria imposed by the regulations, as well as provide a disposable waste container with good transportation efficiency and minimum operational constraints

  18. 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.

  19. [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.

  20. 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.

  1. Direct high-temperature ohmic heating of metals as liquid pipes.

    Science.gov (United States)

    Grosse, A V; Cahill, J A; Liddell, W L; Murphy, W J; Stokes, C S

    1968-05-03

    When a sufficiently high electric current is passed through a liquid metal, the electromagnetic pressure pinches off the liquid metal and interrupts the flow of current. For the first time the pinch effect has been overcome by use of centrifugal acceleration. By rotation of a pipe of liquid metal, tin or bismuth or their alloys, at sufficiently high speed, it can be heated electrically without intermission of the electric current. One may now heat liquid metallic substances, by resistive (ohmic) heating, to 5000 degrees K and perhaps higher temperatures.

  2. Pressure induced Ag{sub 2}Te polymorphs in conjunction with topological non trivial to metal transition

    Energy Technology Data Exchange (ETDEWEB)

    Zhu, J.; Zhang, S. J., E-mail: sjzhang@iphy.ac.cn, E-mail: jin@iphy.ac.cn; Yu, X. H.; Yu, R. C.; Jin, C. Q., E-mail: sjzhang@iphy.ac.cn, E-mail: jin@iphy.ac.cn; Dai, X.; Fang, Z. [Institute of Physics, Chinese Academy of Sciences, Beijing 100190 (China); Oganov, A. R. [Department of Geosciences, University of New York at Stony Brook (United States); Feng, W. X.; Yao, Y. G. [Department of Physics, Beijing Institute of Technology, Beijing (China); Zhu, J. L. [High Pressure Science and Engineering Center, University of Nevada, Las Vegas, Nevada 89154 (United States); Zhao, Y. S. [Institute of Physics, Chinese Academy of Sciences, Beijing 100190 (China); South University of Science and Technology of China, Shenzhen, Guangdong (China)

    2016-08-15

    Silver telluride (Ag{sub 2}Te) is well known as superionic conductor and topological insulator with polymorphs. Pressure induced three phase transitions in Ag{sub 2}Te have been reported in previous. Here, we experimentally identified high pressure phase above 13 GPa of Ag{sub 2}Te by using high pressure synchrotron x ray diffraction method in combination with evolutionary crystal structure prediction, showing it crystallizes into a monoclinic structure of space group C2/m with lattice parameters a = 6.081Å, b = 5.744Å, c = 6.797 Å, β = 105.53°. The electronic properties measurements of Ag{sub 2}Te reveal that the topologically non-trivial semiconducting phase I and semimetallic phase II previously predicated by theory transformed into bulk metals for high pressure phases in consistent with the first principles calculations.

  3. Thermoelasticity at High Temperatures and Pressures for Ta

    International Nuclear Information System (INIS)

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

    2004-01-01

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

  4. High pressure synthesis of ThB/sub 12/ and HfB/sub 12/

    Energy Technology Data Exchange (ETDEWEB)

    Cannon, J F; Farnsworth, P B [Brigham Young Univ., Provo, UT (USA). Dept. of Chemistry

    1938-08-01

    High pressure synthesis techniques were used to prepare ThB/sub 12/ and HfB/sub 12/. These compounds have the cubic UB/sub 12/-type structure with lattice parameters 7.612(1) A and 7.377(2) A respectively. The relationship between the lattice parameter for UB/sub 12/-type dodecaborides and the coordination number 12 radius of the metal atom differs for lanthanide, actinide and transition metal atoms. The prediction is made that it is possible to prepare AmB/sub 12/ at high pressures.

  5. 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

  6. 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.

  7. 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)

  8. 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

  9. 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

  10. 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)

  11. 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 ...

  12. 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 ...

  13. 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 ...

  14. High pressure synthesis of BiS2

    DEFF Research Database (Denmark)

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

    crystal structures and electrical properties.1,2 Up until now, the most sulfur rich phase in the Bi-S phase diagram was Bi2S3.3 For BiS2 the Bi atoms have anisotropic charge distribution and more complex structures are expected when comparing the layered structures of transition metal dichalcogenides....... The possibilities of using high pressure synthesis to discover new phases in the Bi-S binary system were investigated as early as the 1960’s.4 The research led to discovery of a compound with BiS2 stoichiometry, but no structure solution of BiS2 was reported. A reason behind making this new phase is to study...... the physical properties since the related compound Bi2S3 is known to be a thermoelectric material.5 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...

  15. Systems and Methods for Fabricating Structures Including Metallic Glass-Based Materials Using Low Pressure Casting

    Science.gov (United States)

    Hofmann, Douglas C. (Inventor); Kennett, Andrew (Inventor)

    2018-01-01

    Systems and methods to fabricate objects including metallic glass-based materials using low-pressure casting techniques are described. In one embodiment, a method of fabricating an object that includes a metallic glass-based material includes: introducing molten alloy into a mold cavity defined by a mold using a low enough pressure such that the molten alloy does not conform to features of the mold cavity that are smaller than 100 microns; and cooling the molten alloy such that it solidifies, the solid including a metallic glass-based material.

  16. 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.

  17. MHD pressure drop of imperfect insulation of liquid metal flow

    International Nuclear Information System (INIS)

    Horiike, H.; Nishiura, R.; Inoue, S.; Miyazaki, K.

    2000-01-01

    An experiment was performed to study magnetohydrodynamic (MHD) pressure gradient in the case of an imperfect electric insulation coating when using NaK loop. Test channels with uniform defects in their coating were made by painting inner surface with acrylic lacquer insulation. It was found that the exponent to B -- which is 1 for insulated walls, and 2 for conducting ones, was very sensitive to crack fractions lower than 25%. The pressure gradient was found to increase almost linearly with the fraction

  18. 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.

  19. Strongly correlated electrons at high pressure: an approach by inelastic X-Ray scattering

    International Nuclear Information System (INIS)

    Rueff, J.P.

    2007-06-01

    Inelastic X-ray scattering (IXS) and associated methods has turn out to be a powerful alternative for high-pressure physics. It is an all-photon technique fully compatible with high-pressure environments and applicable to a vast range of materials. Standard focalization of X-ray in the range of 100 microns is typical of the sample size in the pressure cell. Our main aim is to provide an overview of experimental results obtained by IXS under high pressure in 2 classes of materials which have been at the origin of the renewal of condensed matter physics: strongly correlated transition metal oxides and rare-earth compounds. Under pressure, d and f-electron materials show behaviors far more complex that what would be expected from a simplistic band picture of electron delocalization. These spectroscopic studies have revealed unusual phenomena in the electronic degrees of freedom, brought up by the increased density, the changes in the charge-carrier concentration, the over-lapping between orbitals, and hybridization under high pressure conditions. Particularly we discuss about pressure induced magnetic collapse and metal-insulator transitions in 3d compounds and valence fluctuations phenomena in 4f and 5f compounds. Thanks to its superior penetration depth, chemical selectivity and resonant enhancement, resonant inelastic X-ray scattering has appeared extremely well suited to high pressure physics in strongly correlated materials. (A.C.)

  20. 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

  1. 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...

  2. 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...

  3. 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...

  4. Low-density to high-density transition in Ce75Al23Si2 metallic glass

    International Nuclear Information System (INIS)

    Zeng, Q S; Lou, H B; Gong, Y; Wang, X D; Jiang, J Z; Fang, Y Z; Wu, F M; Yang, K; Li, A G; Yan, S; Yu, X H; Lathe, C

    2010-01-01

    Using in situ high-pressure x-ray diffraction (XRD), we observed a pressure-induced polyamorphic transition from the low-density amorphous (LDA) state to the high-density amorphous (HDA) state in Ce 75 Al 23 Si 2 metallic glass at about 2 GPa and 300 K. The thermal stabilities of both LDA and HDA metallic glasses were further investigated using in situ high-temperature and high-pressure XRD, which revealed different pressure dependences of the onset crystallization temperature (T x ) between them with a turning point at about 2 GPa. Compared with Ce 75 Al 25 metallic glass, minor Si doping shifts the onset polyamorphic transition pressure from 1.5 to 2 GPa and obviously stabilizes both LDA and HDA metallic glasses with higher T x and changes their slopes dT x /dP. The results obtained in this work reveal another polyamorphous metallic glass system by minor alloying (e.g. Si), which could modify the transition pressure and also properties of LDA and HDA metallic glasses. The minor alloying effect reported here is valuable for the development of more polyamorphous metallic glasses, even multicomponent bulk metallic glasses with modified properties, which will trigger more investigations in this field and improve our understanding of polyamorphism and metallic glasses.

  5. 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

  6. Direct Observation of the Pressure-Induced Semiconductor-To-Metal Transition in Yb Monochalcogenides

    International Nuclear Information System (INIS)

    Matsunami, M.; Chen, L.; Nanba, T.; Ochiai, A.

    2003-01-01

    We have measured infrared absorption spectra under pressure and reflectivity spectra of YbS in the wide photon energy range from 7 meV to 30 eV. The absorption edge shifts linearly toward lower energy with pressure, and above 11 GPa it disappeared in the infrared energy region. The results are considered to correspond to the development of a f-d mixing above this pressure, which lead to an occurrence of the semiconductor-to- metal transition. (author)

  7. Physics of mercury-free high-pressure discharge lamps

    International Nuclear Information System (INIS)

    Born, M

    2002-01-01

    This paper gives a summary of recent results about the replacement of mercury in high-pressure discharge lamps by metallic zinc. Actually, this topic is of high relevance for the lighting industry due to the need of more environmentally friendly products. The work presented here is supported by the German government under contract no 13N8072 and 13N8264. Due to upcoming European legislations which are expected for the year 2003, the replacement of mercury in lighting products is a high priority task. For example, mercury-free headlight discharge lamps are requested by the automotive industry. Pure zinc/argon discharges as well as lamps including zinc or mercury and metal halide additives are investigated. Experimental data are compared with model calculations of the energy balance involving the transport of heat and radiation. Since the excitation energies of relevant zinc transitions are lower than for mercury, axis temperatures of pure zinc lamps are about 300 K below the value of mercury arcs. In addition, the thermal conductivity of zinc including the contribution of radiation diffusion is larger than compared to mercury. From lamp voltage measurements it is found that the cross section for elastical electron scattering by zinc atoms is about the same than for mercury. When adding metal halides to a pure zinc discharge with argon as a starting gas, i.e. NaI, TlI, DyI 3 , axis temperatures decrease to about 5100 K due to strong radiation cooling. In order to obtain sufficiently large lamp voltages, wall temperatures of more than 1300 K are adjusted by means of polycrystalline aluminaoxide (Al 2 O 3 ) as a wall material. Electric field strengths of 6.0 and 8.6 V mm -1 are measured for metal halide lamps containing zinc or mercury, respectively. The light technical data of the discharges are very close, since mercury and zinc do not contribute significantly to the radiation in the visible range. Efficacies of up to 93 and 100 lm W -1 are found in metal halide

  8. 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.

  9. Parametric studies on containment thermal hydraulic loads during high pressure melt ejection in a BWR

    Energy Technology Data Exchange (ETDEWEB)

    Silde, A.; Lindholm, I. [VTT Energy, Espoo (Finland)

    1997-12-01

    The containment thermal hydraulic loads during high pressure melt ejection in a Nordic BWR are studied parametrically with the CONTAIN and the MELCOR codes. The work is part of the Nordic RAK-2 project. The containment analyses were divided into two categories according to composition of the discharged debris: metallic and oxidic debris cases. In the base case with highly metallic debris, all sources from the reactor coolant system to the containment were based on the MELCOR/BH calculation. In the base case with the oxidic debris, the source data was specified assuming that {approx} 15% of the whole core material inventory and 34,000 kg of saturated water was discharged from the reactor pressure vessel (RPV) during 30 seconds. In this case, the debris consisted mostly of oxides. The highest predicted containment pressure peaks were about 8.5 bar. In the scenarios with highly metallic debris source, very high gas temperature of about 1900 K was predicted in the pedestal, and about 1400 K in the upper drywell. The calculations with metallic debris were sensititive to model parameters, like the particle size and the parameters, which control the chemical reaction kinetics. In the scenarios with oxidic debris source, the predicted pressure peaks were comparable to the cases with the metallic debris source. The maximum gas temperatures (about 450-500 K) in the containment were, however, significantly lower than in the respective metallic debris case. The temperatures were also insensitive to parametric variations. In addition, one analysis was performed with the MELCOR code for benchmarking of the MELCOR capabilities against the more detailed CONTAIN code. The calculations showed that leak tightness of the containment penetrations could be jeopardized due to high temperature loads, if a high pressure melt ejection occurred during a severe accident. Another consequence would be an early containment venting. (au). 28 refs.

  10. Empirical Method to Estimate Hydrogen Embrittlement of Metals as a Function of Hydrogen Gas Pressure at Constant Temperature

    Science.gov (United States)

    Lee, Jonathan A.

    2010-01-01

    High pressure Hydrogen (H) gas has been known to have a deleterious effect on the mechanical properties of certain metals, particularly, the notched tensile strength, fracture toughness and ductility. The ratio of these properties in Hydrogen as compared to Helium or Air is called the Hydrogen Environment Embrittlement (HEE) Index, which is a useful method to classify the severity of H embrittlement and to aid in the material screening and selection for safety usage H gas environment. A comprehensive world-wide database compilation, in the past 50 years, has shown that the HEE index is mostly collected at two conveniently high H pressure points of 5 ksi and 10 ksi near room temperature. Since H embrittlement is directly related to pressure, the lack of HEE index at other pressure points has posed a technical problem for the designers to select appropriate materials at a specific H pressure for various applications in aerospace, alternate and renewable energy sectors for an emerging hydrogen economy. Based on the Power-Law mathematical relationship, an empirical method to accurately predict the HEE index, as a function of H pressure at constant temperature, is presented with a brief review on Sievert's law for gas-metal absorption.

  11. Universal viscosity growth in metallic melts at megabar pressures: the vitreous state of the Earth's inner core

    International Nuclear Information System (INIS)

    Brazhkin, Vadim V; Lyapin, A G

    2000-01-01

    Experimental data on and theoretical models for the viscosity of various types of liquids and melts under pressure are reviewed. Experimentally, the least studied melts are those of metals, whose viscosity is considered to be virtually constant along the melting curve. The authors' new approach to the viscosity of melts involves the measurement of the grain size in solidified samples. Measurements on liquid metals at pressures up to 10 GPa using this method show, contrary to the empirical approach, that the melt viscosity grows considerably along the melting curves. Based on the experimental data and on the critical analysis of current theories, a hypothesis of a universal viscosity behavior is introduced for liquids under pressure. Extrapolating the liquid iron results to the pressures and temperatures at the Earth's core reveals that the Earth's outer core is a very viscous melt with viscosity values ranging from 10 2 Pa s to 10 11 Pa s depending on the depth. The Earth's inner core is presumably an ultraviscous (>10 11 Pa s) glass-like liquid - in disagreement with the current idea of a crystalline inner core. The notion of the highly viscous interior of celestial bodies sheds light on many mysteries of planetary geophysics and astronomy. From the analysis of the pressure variation of the melting and glass-transition temperatures, an entirely new concept of a stable metallic vitreous state arises, calling for further experimental and theoretical study. (reviews of topical problems)

  12. 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

  13. Physical aspects of mercury-free high pressure discharge lamps

    International Nuclear Information System (INIS)

    Born, M.

    2002-01-01

    This paper gives a summary of recent results about the replacement of mercury in high pressure discharge lamps by metallic zinc. Actually, this topic is of high relevance for the lighting industry due to the need of more environmentally friendly products. The work presented here is supported by the German government under contract no. 13N8072. Pure zinc/argon discharges as well as lamps including zinc or mercury and metal halide additives are investigated. Experimental data are compared with model calculations of the energy balance involving the transport of heat and radiation. Since the excitation energies of relevant zinc transistions are lower than for mercury, axis temperatures of pure zinc lamps are about 300 K below the value of mercury arcs. In addition, the thermal conductivity of zinc including the contribution of radiation diffusion is larger than compared to mercury. From lamp voltage measurements it is found that the cross section for elastical electron scattering by zinc atoms is about the same as for mercury. When adding metal halides to a pure zinc discharge with argon as a starting gas, i.e. NaI, TlI, DyI3, axis temperatures decrease to about 5100 K due to strong radiation cooling. In order to obtain sufficiently large lamp voltages, wall temperatures of more than 1300 K are adjusted by means of polycrystalline aluminaoxide (Al2O3) as a wall material. Electrical field strenghts of 6.0 V/mm and 8.6 V/mm are measured for metal halide lamps containing zinc or mercury, respectively. The light technical data of the discharges are very close, since mercury and zinc do not contribute significantly to the radiation in the visible range. Efficacies of up to 93 lm/W and 100 lm/W are found in metal halide lamps with zinc and mercury, respectively. Consequently, zinc turns out to be an attractive replacer for mercury in this type of lamp not only from an environmental point of view

  14. 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

  15. High-precision gauging of metal rings

    Science.gov (United States)

    Carlin, Mats; Lillekjendlie, Bjorn

    1994-11-01

    Raufoss AS designs and produces air brake fittings for trucks and buses on the international market. One of the critical components in the fittings is a small, circular metal ring, which is going through 100% dimension control. This article describes a low-price, high accuracy solution developed at SINTEF Instrumentation based on image metrology and a subpixel resolution algorithm. The measurement system consists of a PC-plugg-in transputer video board, a CCD camera, telecentric optics and a machine vision strobe. We describe the measurement technique in some detail, as well as the robust statistical techniques found to be essential in the real life environment.

  16. 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.

  17. 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.)

  18. Influences of the Air in Metal Powder High Velocity Compaction

    Directory of Open Access Journals (Sweden)

    Liu Jun

    2017-01-01

    Full Text Available During the process of metal powder high velocity impact compaction, the air is compressed sharply and portion remains in the compacts. In order to study the Influences, a discrete density volleyball accumulation model for aluminium powder was established with the use of ABAQUS. Study found that the powder porosity air obstruct the pressing process because remaining air reduced strength and density of the compacts in the current high-speed pressing (V≤100m/s. When speed further increased (V≥100m/s, the temperature of the air increased sharply, and was even much higher than the melting point of the material. When aluminium powder was compressed at a speed of 200m/s, temperatures of air could reach 2033 K, far higher than the melting point of 877 K. Increased density of powders was a result of local softening and even melt adhesive while air between particles with high temperature and pressure flowed past.

  19. 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.

  20. 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.

  1. 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.

  2. 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.

  3. 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.

  4. 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 ...

  5. 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...

  6. 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.

  7. A Historical Review of High Speed Metal Forming

    OpenAIRE

    Zittel, G.

    2010-01-01

    This paper will present a Historical Review of High Speed Metal Forming beginning with the first thought of forming metal by using an electromagnetic impulse to today, whereby High Speed Metal Forming is an accepted production process. Although this paper will briefly cover the basic physics of the process, it will not dwell on it. It will rather show how the industrial acceptance of High Speed Metal Forming is tightly connected to the knowledge acquired from many applications studies. These ...

  8. Investigation of the Mesostructure of Transition-Metal Monogermanides Synthesized under Pressure

    Science.gov (United States)

    Safiulina, I. A.; Altynbaev, E. V.; Iashina, E. G.; Heinemann, A.; Fomicheva, L. N.; Tsvyashchenko, A. V.; Grigoriev, S. V.

    2018-04-01

    The mesostructure of transition-metal monogermanides Mn1 - x Co x Ge is studied by small-angle neutron scattering in a wide range of concentrations x = 0-0.95. These compounds were synthesized under high pressure and are metastable under normal conditions. The experimental dependences I( Q) obtained for the whole series of samples in the range of transferred momenta (6 × 10-2 nm-1 interesting to note that such defects are absent in the isostructural FeGe compound, i.e., the experimental dependences of the intensity are described well by the expression Q - n with an exponent n = 4.1 ± 0.1, which demonstrates the presence of crystallites with a uniform density distribution inside and a sharp boundary characterizing the surface.

  9. 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 ...

  10. Adaptive metal mirror for high-power CO2 lasers

    Science.gov (United States)

    Jarosch, Uwe-Klaus

    1996-08-01

    Spherical mirrors with a variable radius of curvature are used inside laser resonators as well as in the beam path between the laser and the workpiece. Commercially-available systems use piezoelectric actuators, or the pressure of the coolant, to deform the mirror surface. In both cases, the actuator and the cooling system influence each other. This interaction is avoided through the integration of the cooling system with the flexible mirror membrane. A multi- channel design leads to an optimized cooling effect, which is necessary for high power applications. The contour of the variable metal mirror depends on the mounting between the membrane and the mirror body and on the distribution of forces. Four cases of deformation can be distinguished for a circular elastic membrane. The realization of an adaptive metal mirror requires a technical compromise to be made. A mechanical construction is presented which combines an elastic hinge with the inlet and outlet of the coolant. For the deformation of the mirror membranes two actuators with different character of deformation are used. The superposition of the two deformations results in smaller deviations from the spherical surface shape than can be achieved using a single actuator. DC proportional magnets have been introduced as cheap and rigid actuators. The use of this adaptive mirror, either in a low pressure atmosphere of a gas laser resonator, or in an extra-cavity beam path is made possible through the use of a ventilation system.

  11. Pressure vessels fabricated with high-strength wire and electroformed nickel

    Science.gov (United States)

    Roth, B.

    1966-01-01

    Metal pressure vessels of various shapes having high strength-to-weight ratios are fabricated by using known techniques of filament winding and electroforming. This eliminates nonuniform wall thickness and unequal wall strength which resulted from welding formed vessel segments together.

  12. On the use of distorted fcc structures for describing high-pressure phases

    International Nuclear Information System (INIS)

    Gerward, L.; Staun Olsen, J.; Benedict, U.

    1986-01-01

    The paper describes distorted lattices that can be derived from the face-centred cubic Bravais lattice. Crystallographic principles are outlined and it is discussed how various lattices can be identified from the observed splitting of X-ray powder diffraction lines. Examples are taken from recent high-pressure studies of actinide rocksalt structure compounds and cerium metal. (orig.)

  13. Predicted crystal structures of molybdenum under high pressure

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Bing; Zhang, Guang Biao [Institute for Computational Materials Science, School of Physics and Electronics, Henan University, Kaifeng 475004 (China); Wang, Yuan Xu, E-mail: wangyx@henu.edu.cn [Institute for Computational Materials Science, School of Physics and Electronics, Henan University, Kaifeng 475004 (China); Guizhou Provincial Key Laboratory of Computational Nano-Material Science, Institute of Applied Physics, Guizhou Normal College, Guiyang 550018 (China)

    2013-04-15

    Highlights: ► A double-hexagonal close-packed (dhcp) structure of molybdenum is predicted. ► Calculated acoustic velocity confirms the bcc–dhcp phase transition at 660 GPa. ► The valence electrons of dhcp Mo are mostly localized in the interstitial sites. -- Abstract: The high-pressure structures of molybdenum (Mo) at zero temperature have been extensively explored through the newly developed particle swarm optimization (PSO) algorithm on crystal structural prediction. All the experimental and earlier theoretical structures were successfully reproduced in certain pressure ranges, validating our methodology in application to Mo. A double-hexagonal close-packed (dhcp) structure found by Mikhaylushkin et al. (2008) [12] is confirmed by the present PSO calculations. The lattice parameters and physical properties of the dhcp phase were investigated based on first principles calculations. The phase transition occurs only from bcc phase to dhcp phase at 660 GPa and at zero temperature. The calculated acoustic velocities also indicate a transition from the bcc to dhcp phases for Mo. More intriguingly, the calculated density of states (DOS) shows that the dhcp structure remains metallic. The calculated electron density difference (EDD) reveals that its valence electrons are localized in the interstitial regions.

  14. 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...

  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. Uniaxial pressure-induced half-metallic ferromagnetic phase transition in LaMnO3

    Science.gov (United States)

    Rivero, Pablo; Meunier, Vincent; Shelton, William

    2016-03-01

    We use first-principles theory to predict that the application of uniaxial compressive strain leads to a transition from an antiferromagnetic insulator to a ferromagnetic half-metal phase in LaMnO3. We identify the Q2 Jahn-Teller mode as the primary mechanism that drives the transition, indicating that this mode can be used to tune the lattice, charge, and spin coupling. Applying ≃6 GPa of uniaxial pressure along the [010] direction activates the transition to a half-metallic pseudocubic state. The half-metallicity opens the possibility of producing colossal magnetoresistance in the stoichiometric LaMnO3 compound at significantly lower pressure compared to recently observed investigations using hydrostatic pressure.

  17. Brazing refractory metals used in high-temperature nuclear instrumentation

    International Nuclear Information System (INIS)

    Palmer, A. J.; Woolstenhulme, C. J.

    2009-01-01

    As part of the U. S. Department of Energy (DOE)-sponsored Next Generation Nuclear Project (NGNP) currently ongoing at Idaho National Laboratory (INL), the irradiation performance of candidate high-temperature gas reactor fuels and materials is being evaluated at INL's Advanced Test Reactor (ATR). The design of the first Advanced Gas Reactor (AGR-1) TRISO fuel experiment, currently being irradiated in the ATR, required development of special techniques for brazing niobium and molybdenum. Brazing is one technique used to join refractory metals to each other and to stainless steel alloys. Although brazing processes are well established, it is difficult to braze niobium, molybdenum, and most other refractory metals because they quickly develop adherent oxides when exposed to room-temperature air. Specialized techniques and methods were developed by INL to overcome these obstacles. This paper describes the techniques developed for removing these oxides, as well as the ASME Section IX-qualified braze procedures that were developed as part of the AGR-1 project. All brazes were made using an induction coil with an inert or reducing atmosphere at low pressure. Other parameters, such as filler metals, fluxes used, and general setup procedures, are also discussed. (authors)

  18. Brazing Refractory Metals Used In High-Temperature Nuclear Instrumentation

    International Nuclear Information System (INIS)

    Palmer, A.J.; Woolstenhulme, C.J.

    2009-01-01

    As part of the U. S. Department of Energy (DOE) sponsored Next Generation Nuclear Project (NGNP) currently ongoing at Idaho National Laboratory (INL), the irradiation performance of candidate high-temperature gas reactor fuels and materials is being evaluated at INL's Advanced Test Reactor (ATR). The design of the first Advanced Gas Reactor (AGR 1) experiment, currently being irradiated in the ATR, required development of special techniques for brazing niobium and molybdenum. Brazing is one technique used to join refractory metals to each other and to stainless steel alloys. Although brazing processes are well established, it is difficult to braze niobium, molybdenum, and most other refractory metals because they quickly develop adherent oxides when exposed to room-temperature air. Specialized techniques and methods were developed by INL to overcome these obstacles. This paper describes the techniques developed for removing these oxides, as well as the ASME Section IX-qualified braze procedures that were developed as part of the AGR-1 project. All brazes were made using an induction coil with an inert or reducing atmosphere at low pressure. Other parameters, such as filler metals, fluxes used, and general setup procedures, are also discussed

  19. Brazing refractory metals used in high-temperature nuclear instrumentation

    Energy Technology Data Exchange (ETDEWEB)

    Palmer, A. J. [Idaho National Laboratory, MS 3840, P.O. Box 1625, Idaho Falls, ID 83415-3840 (United States); Woolstenhulme, C. J. [EG and G Services, Inc., (United States)

    2009-07-01

    As part of the U. S. Department of Energy (DOE)-sponsored Next Generation Nuclear Project (NGNP) currently ongoing at Idaho National Laboratory (INL), the irradiation performance of candidate high-temperature gas reactor fuels and materials is being evaluated at INL's Advanced Test Reactor (ATR). The design of the first Advanced Gas Reactor (AGR-1) TRISO fuel experiment, currently being irradiated in the ATR, required development of special techniques for brazing niobium and molybdenum. Brazing is one technique used to join refractory metals to each other and to stainless steel alloys. Although brazing processes are well established, it is difficult to braze niobium, molybdenum, and most other refractory metals because they quickly develop adherent oxides when exposed to room-temperature air. Specialized techniques and methods were developed by INL to overcome these obstacles. This paper describes the techniques developed for removing these oxides, as well as the ASME Section IX-qualified braze procedures that were developed as part of the AGR-1 project. All brazes were made using an induction coil with an inert or reducing atmosphere at low pressure. Other parameters, such as filler metals, fluxes used, and general setup procedures, are also discussed. (authors)

  20. 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.

  1. Analysis of thermal expansivity of iron (Fe) metal at ultra high ...

    Indian Academy of Sciences (India)

    structure are unlikely to be successful for predicting the high temperature properties of transition metals due to the complicated many-body nature of the interactions. Wasserman et al [3] have recently studied the thermal properties of iron at high pressures and temperatures within the framework of shell model [7,8], which is ...

  2. Relation between the electrolytic solution pressures of the metals and their toxicity to the stickleback (Gasterosteus acelueatus l. )

    Energy Technology Data Exchange (ETDEWEB)

    Jones, J R.E.

    1939-01-01

    Lethal concentration limits have been determined for the hydrogen ion and the ions of eighteen metals. The three-spined stickleback (Gasterosteus aculeatus l.) has been employed as test animal. According to their lethal concentration limits on a mg./l. basis their order of increasing toxicity is: Sr, Ca, Na, Ba, Mg, K, Mn, Co, Cr, Ni, Au, Zn, Cd, Pb, Al, Cu, H, Hg, and Ag. On a molar concentration basis the order is as follows: Na, Ca, Sr, Mg, Ba, K, Mn, Co, Cr, Ni, H, Zn, Al, Au, Cd, Pb, Cu, Hg, Ag. All these ions, with the exception of the first six (the metals of the alkalis and alkaline earths), bring about the death of fish by precipitating the gill secretions, thus causing asphyxiation. The alkali and alkaline earth metals appear to enter the body and act as true internal poisons. The position of iron is uncertain. The toxicity of solutions of iron salts appears to be due, mainly if not entirely, to their acidity. On a mg./l. or molar concentration basis there is a marked relationship between the toxicity of the metals and their solution pressures. The metals of very low solution pressure (Ag, Cu, etc.), i.e. those whose ions are most ready to part with their charges and enter into combination with other ions or compounds, are the most toxic as they precipitate the gill secretions and bring about asphyxiation with extreme rapidity. Metals of somewhat higher solution pressure (Zn, Pb, Cd) act in the same way but more slowly. Manganese, which of all the heavy metals has the highest solution pressure, takes effect very slowly and the ions of the alkali and alkaline earth metals, which have a high affinity for their charges, do not precipitate the gill secretions at all. In the case of all ions other than those of the alkali and alkaline earth metals the reactions responsible for the death of the fish take place outside the body. Thus their speed of action does not depend on their penetrating power and the permeability factor does not enter.

  3. 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

  4. 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.

  5. Ab initio study of properties of BaBiO3 at high pressure

    Science.gov (United States)

    Martoňák, Roman; Ceresoli, Davide; Kagayama, Tomoko; Tosatti, Erio

    BaBiO3 is a mixed-valence perovskite which escapes metallic state by creating a Bi-O bond disproportionation or CDW pattern, resulting in a Peierls semiconductor with gap of nearly 1 eV at zero pressure. Evolution of structural and electronic properties at high pressure is, however, largely unknown. Pressure, it might be natural to expect, could reduce the bond-disproportionation and bring the system closer to metalicity or even superconductivity. We address this question by ab initio DFT methods based on GGA and hybrid functionals in combination with crystal structure prediction techniques based on genetic algorithms. We analyze the pressure evolution of bond disproportionation as well as other order parameters related to octahedra rotation for various phases in connection with corresponding evolution of the electronic structure. Results indicate that BaBiO3 continues to resist metalization also under pressure, through structural phase transitions which sustain and in fact increase the diversity of length of Bi-O bonds for neighboring Bi ions, in agreement with preliminary high pressure resistivity data. R.M. Slovak Research and Development Agency Contract APVV-15-0496, VEGA project No. 1-0904-15; E.T. ERC MODPHYSFRICT Advanced Grant No. 320796.

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

    DEFF Research Database (Denmark)

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

    2001-01-01

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

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

    International Nuclear Information System (INIS)

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

    2009-01-01

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

  8. 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.

  9. Size-dependent structure of silver nanoparticles under high pressure

    Energy Technology Data Exchange (ETDEWEB)

    Koski, Kristie Jo [Univ. of California, Berkeley, CA (United States)

    2008-12-31

    Silver noble metal nanoparticles that are<10 nm often possess multiply twinned grains allowing them to adopt shapes and atomic structures not observed in bulk materials. The properties exhibited by particles with multiply twinned polycrystalline structures are often far different from those of single-crystalline particles and from the bulk. I will present experimental evidence that silver nanoparticles<10 nm undergo a reversible structural transformation under hydrostatic pressures up to 10 GPa. Results for nanoparticles in the intermediate size range of 5 to 10 nm suggest a reversible linear pressure-dependent rhombohedral distortion which has not been previously observed in bulk silver. I propose a mechanism for this transitiion that considers the bond-length distribution in idealized multiply twinned icosahedral particles. Results for nanoparticles of 3.9 nm suggest a reversible linear pressure-dependent orthorhombic distortion. This distortion is interpreted in the context of idealized decahedral particles. In addition, given these size-dependent measurements of silver nanoparticle compression with pressure, we have constructed a pressure calibration curve. Encapsulating these silver nanoparticles in hollow metal oxide nanospheres then allows us to measure the pressure inside a nanoshell using x-ray diffraction. We demonstrate the measurement of pressure gradients across nanoshells and show that these nanoshells have maximum resolved shear strengths on the order of 500 MPa to IGPa.

  10. 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)

  11. 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)

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

    NARCIS (Netherlands)

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

    2002-01-01

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

  13. 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

  14. Development of metallic high integrity containers

    International Nuclear Information System (INIS)

    Temus, C.J.; Porter, S.A.; Kent, J.D.; Goetsch, S.D.

    1985-01-01

    This paper presents the development program for metallic high integrity containers (HIC's). The need for a high strength, thin walled HIC became apparent with the implementation of 10 CFR 61 in late 1983. The existing containers that were in use at that time were made of either low strength material (polyethylene) or bulky, heavy material (concrete). Neither of these materials met the need for a high strength, volume and weight efficient container that could survive the deep burial environment of sites such as Hanford, Washington. Various alloys were considered for corrosion resistance for a 300 year life, high strength and toughness, and elastic stability to meet the requirements of 10 CFR 61. The alloy allowed for great flexibility in design to accommodate various waste forms. The containers were developed in various sizes with several different closures designed to minimize operator exposure during the loading operation. These design features provide the industry with efficient, disposable packages for a wide variety of waste forms. The paper describes the analytical methodology and prototype test program. The analytical methods included finite element modeling of the burial conditions, prediction of drop performance,and elastic stability analysis. Prototype testing included leak tests and drop tests at various container orientations from heights of up to 25 feet

  15. Fracture toughness and crack growth resistance of pressure vessel plate and weld metal steels

    International Nuclear Information System (INIS)

    Moskovic, R.

    1988-01-01

    Compact tension specimens were used to measure the initiation fracture toughness and crack growth resistance of pressure vessel steel plates and submerged arc weld metal. Plate test specimens were manufactured from four different casts of steel comprising: aluminium killed C-Mn-Mo-Cu and C-Mn steel and two silicon killed C-Mn steels. Unionmelt No. 2 weld metal test specimens were extracted from welds of double V butt geometry having either the C-Mn-Mo-Cu steel (three weld joints) or one particular silicon killed C-Mn steel (two weld joints) as parent plate. A multiple specimen test technique was used to obtain crack growth data which were analysed by simple linear regression to determine the crack growth resistance lines and to derive the initiation fracture toughness values for each test temperature. These regression lines were highly scattered with respect to temperature and it was very difficult to determine precisely the temperature dependence of the initiation fracture toughness and crack growth resistance. The data were re-analysed, using a multiple linear regression method, to obtain a relationship between the materials' crack growth resistance and toughness, and the principal independent variables (temperature, crack growth, weld joint code and strain ageing). (author)

  16. High-temperature spreading kinetics of metals

    Energy Technology Data Exchange (ETDEWEB)

    Rauch, N.

    2005-05-15

    In this PhD work a drop transfer setup combined with high speed photography has been used to analyze the spreading of Ag on polished polycrystalline Mo and single crystalline Mo (110) and (100) substrates. The objective of this work was to unveil the basic phenomena controlling spreading in metal-metal systems. The observed spreading kinetics were compared with current theories of low and high temperature spreading such as a molecular kinetic model and a fluid flow model. Analyses of the data reveal that the molecular model does describe the fastest velocity data well for all the investigated systems. Therefore, the energy which is dissipated during the spreading process is a dissipation at the triple line rather than dissipation due to the viscosity in the liquid. A comparison of the determined free activation energy for wetting of {delta}G95{approx}145kJ/mol with literature values allows the statement that the rate determining step seems to be a surface diffusion of the Ag atoms along the triple line. In order to investigate possible ridge formation, due to local atomic diffusion of atoms of the substrate at the triple during the spreading process, grooving experiments of the polycrystalline Mo were performed to calculate the surface diffusities that will control ridge evolution. The analyses of this work showed that a ridge formation at the fastest reported wetting velocities was not possible if there is no initial perturbation for a ridge. If there was an initial perturbation for a ridge the ridge had to be much smaller than 1 nm in order to be able to move with the liquid font. Therefore ridge formation does not influence the spreading kinetics for the studied system and the chosen conditions. SEM, AFM and TEM investigations of the triple line showed that ridge formation does also not occur at the end of the wetting experiment when the drop is close to equilibrium and the wetting velocity is slow. (orig.)

  17. On the estimation of threshold pressures in infiltration of liquid metals into particle preforms

    International Nuclear Information System (INIS)

    Molina, J.M.; Prieto, R.; Duarte, M.; Narciso, J.; Louis, E.

    2008-01-01

    Threshold pressures for infiltration of different metals into preforms of ceramic particles of various nature and morphology were experimentally determined and the results compared with those estimated by using the specific particle surface areas derived from laser diffraction and gas adsorption. Whilst laser diffraction provides an under estimation of the areas involved in the infiltration experiments, and thus of threshold pressures, gas adsorption offers reasonable values for particles that are regular and free of nanostructured surfaces

  18. High Pressure Optical Studies of the Thallous Halides and of Charge-Transfer Complexes

    Science.gov (United States)

    Jurgensen, Charles Willard

    High pressure was used to study the insulator -to-metal transition in sulfur and the thallous halides and to study the intermolecular interactions in charge -transfer complexes. The approach to the band overlap insulator -to-metal transition was studied in three thallous halides and sulfur by optical absorption measurements of the band gap as a function of pressure. The band gap of sulfur continuously decreases with pressure up to the insulator -to-metal transition which occurs between 450 and 485 kbars. The results on the thallous halides indicate that the indirect gap decreases more rapidly than the direct gap; the closing of the indirect gap is responsible for the observed insulator -to-metal transitions. High pressure electronic and vibrational spectroscopic measurements on the solid-state complexes of HMB-TCNE were used to study the intermolecular interactions of charge -transfer complexes. The vibrational frequency shifts indicate that the degree of charge transfer increases with pressure which is independently confirmed by an increase in the molar absorptivity of the electronic charge-transfer peak. Induction and dispersion forces contribute towards a red shift of the charge-transfer peak; however, charge-transfer resonance contributes toward a blue shift and this effect is dominant for the HMB-TCNE complexes. High pressure electronic spectra were used to study the effect of intermolecular interactions on the electronic states of TCNQ and its complexes. The red shifts with pressure of the electronic spectra of TCNQ and (TCNQ)(' -) in polymer media and of crystalline TCNQ can be understood in terms of Van der Waals interactions. None of the calculations which considered intradimer distance obtained the proper behavior for either the charge-transfer of the locally excited states of the complexes. The qualitative behavior of both states can be interpreted as the effect of increased mixing of the locally excited and charge transfer states.

  19. Conventional superconductivity at 203 K at high pressures

    Energy Technology Data Exchange (ETDEWEB)

    Drozdov, Alexander; Eremets, Mikhail; Troyan, Ivan [Max-Planck-Institut fuer Chemie, Hahn-Meitner-Weg 1, 55128 Mainz (Germany); Ksenofontov, Vadim; Shylin, Sergii [Institut fuer Anorganische Chemie und Analytische Chemie, Johannes Gutenberg-Universitet Mainz, Staudingerweg 9, 55099 Mainz (Germany)

    2016-07-01

    A search for high, room temperature conventional superconductivity is promising as the Bardeen-Cooper-Schrieffer (BCS) theory in the Eliashberg formulation puts no apparent limits on T{sub c}. Materials with light elements are especially favorable as they provide high frequencies in the phonon spectrum. However only a moderately high T{sub c} = 39 K has been found in this search in MgB{sub 2}. We systematically studied metallic hydrogen and covalent hydrogen dominant compounds and found the record T{sub c} of 203 K at pressure 140 GPa in sulfur hydride. We proved occurrence of superconductivity by the sharp drop of the resistivity to zero; the decrease of T{sub c} with magnetic field; the pronounce isotope shift of T{sub c} in D{sub 2}S which evidences of a major role of phonons in the superconductivity; and the magnetic susceptibility measurements. The X-ray diffraction data confirmed that the superconductive phase has the predicted bcc structure. This phase can be considered as an atomic hydrogen superconductor stabilized by sulfur.

  20. Study of the high power laser-metal interactions in the gaseous atmospheres

    Science.gov (United States)

    Lugomer, Stjepan; Bitelli, G.; Stipancic, M.; Jovic, F.

    1994-08-01

    The tantalum and titanium plates were treated by pulsed, high power CO2 laser in the pressurized atmospheres of N2 and O2. Studies performed by the optical microscopy, microhardness measurements, and the auger electron spectroscopy revealed: (1) topographic modification of the surface caused by the temperature field; (2) metal hardening, caused by the laser shock; and (3) alloying/cladding, caused by the chemical reaction between the metal surface and the gaseous atmosphere.

  1. 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).

  2. 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.

  3. 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.

  4. Ionic conduction in sodium azide under high pressure: Experimental and theoretical approaches

    Science.gov (United States)

    Wang, Qinglin; Ma, Yanzhang; Sang, Dandan; Wang, Xiaoli; Liu, Cailong; Hu, Haiquan; Wang, Wenjun; Zhang, Bingyuan; Fan, Quli; Han, Yonghao; Gao, Chunxiao

    2018-04-01

    Alkali metal azides can be used as starting materials for the synthesis of polymeric nitrogen, a potential material of high energy density. In this letter, we report the ionic transport behavior in sodium azide under high pressure by in situ impedance spectroscopy and density functional theory calculations. The ionic transportation consists of ion transfer and Warburg diffusion processes. The ionic migration channels and barrier energy were given for the high-pressure phases. The enhanced ionic conductivity of the γ phase with pressure is because of the formation of space charge regions in the grain boundaries. This ionic conduction and grain boundary effect in NaN3 under pressures could shed light on the better understanding of the conduction mechanism of alkali azides and open up an area of research for polymeric nitrogen in these compounds and other high-energy-density polynitrides.

  5. EXPERIMENTAL TESTS OF VANADIUM STRENGTH MODELS AT HIGH PRESSURES AND STRAIN RATES

    Energy Technology Data Exchange (ETDEWEB)

    Park, H; Barton, N R; Becker, R C; Bernier, J V; Cavallo, R M; Lorenz, K T; Pollaine, S M; Remington, B A; Rudd, R E

    2010-03-02

    Experimental results showing significant reductions from classical in the Rayleigh-Taylor (RT) instability growth rate due to high pressure material strength or effective lattice viscosity in metal foils are presented. On the Omega Laser in the Laboratory for Laser Energetics, University of Rochester, target samples of polycrystalline vanadium are compressed and accelerated quasi-isentropically at {approx}1 Mbar pressures, while maintaining the samples in the solid-state. Comparison of the results with constitutive models for solid state strength under these conditions show that the measured RT growth is substantially lower than predictions using existing models that work well at low pressures and long time scales. High pressure, high strain rate data can be explained by the enhanced strength due to a phonon drag mechanism, creating a high effective lattice viscosity.

  6. 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.

  7. 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.

  8. 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

  9. 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

  10. 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.

  11. 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

  12. 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.)

  13. 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 ...

  14. 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.)

  15. Heat Transfer in Metal Foam Heat Exchangers at High Temperature

    Science.gov (United States)

    Hafeez, Pakeeza

    Heat transfer though open-cell metal foam is experimentally studied for heat exchanger and heat shield applications at high temperatures (˜750°C). Nickel foam sheets with pore densities of 10 and 40 pores per linear inch (PPI), have been used to make the heat exchangers and heat shields by using thermal spray coating to deposit an Inconel skin on a foam core. Heat transfer measurements were performed on a test rig capable of generating hot gas up to 1000°C. The heat exchangers were tested by exposing their outer surface to combustion gases at a temperature of 550°C and 750°C while being cooled by air flowing through them at room temperature at velocities up to 5 m/s. The temperature rise of the air, the surface temperature of the heat exchangers and the air temperature inside the heat exchanger were measured. The volumetric heat transfer coefficient and Nusselt number were calculated for different velocities. The heat transfer performance of the 40PPI sample brazed with the foil is found to be the most efficient. Pressure drop measurements were also performed for 10 and 40PPI metal foam. Thermographic measurements were done on 40PPI foam heat exchangers using a high temperature infrared camera. A high power electric heater was used to produce hot air at 300°C that passed over the foam heat exchanger while the cooling air was blown through it. Heat shields were made by depositing porous skins on metal foam and it was observed that a small amount of coolant leaking through the pores notably reduces the heat transfer from the hot gases. An analytical model was developed based assuming local thermal non-equilibrium that accounts for the temperature difference between solid and fluid phase. The experimental results are found to be in good agreement with the predicted values of the model.

  16. Modeling of thermal explosion under pressure in metal ceramic systems

    International Nuclear Information System (INIS)

    Shapiro, M.; Dudko, V.; Skachek, B.; Matvienko, A.; Gotman, I.; Gutmanas, E.Y.

    1998-01-01

    The process of reactive in situ synthesis of dense ceramic matrix composites in Ti-B-C, Ti-B-N, Ti-Si-N systems is modeled. These ceramics are fabricated on the basis of compacted blends of ceramic powders, namely Ti-B 4 C and/or Ti-BN. The objectives of the project are to identify and investigate the optimal thermal conditions preferable for production of fully dense ceramic matrix composites. Towards this goal heat transfer and combustion in dense and porous ceramic blends are investigated during monotonous heating at a constant rate. This process is modeled using a heat transfer-combustion model with kinetic parameters determined from the differential thermal analysis of the experimental data. The kinetic burning parameters and the model developed are further used to describe the thermal explosion synthesis in a restrained die under pressure. It is shown that heat removal from the reaction zone affects the combustion process and the final phase composition

  17. 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

  18. 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)

  19. 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

  20. Non-destructive measurement of Xe filling pressure in mercury-free metal halide lamp

    International Nuclear Information System (INIS)

    Motomura, Hideki; Enoki, Kyosuke; Jinno, Masafumi

    2010-01-01

    Mercury-free metal halide lamps (MHLs) for automotive purposes have been developing in the market. When mercury is not used, the electric and emission characteristics of the lamp strongly depend on the xenon filling pressure. Therefore a non-destructive gas pressure estimation technique is required to obtain stable performance of the lamps as commercial products. The authors have developed an estimation method by which the gas pressure is estimated from the current peak value at the initial stage of ignition under pulsed operation. It is shown that accuracy of the order of ±(0.1-0.3) atm is obtained using an empirical formula.

  1. Refractory thermowell for continuous high temperature measurement of molten metal

    International Nuclear Information System (INIS)

    Thiesen, T.J.

    1992-01-01

    This patent describes a vessel for handling molten metal having an interior refractory lining, apparatus for continuous high temperature measurement of the molten metal. It comprises a thermowell; the thermowell containing a multiplicity of thermocouples; leads being coupled to a means for continuously indicating the temperature of the molten metal in the vessel

  2. Phosphorous dimerization in GaP high-pressure polymorph

    Energy Technology Data Exchange (ETDEWEB)

    Lavina, Barbara [Univ. of Nevada, Las Vegas, NV (United States). High Pressure Science and Engineering Center (HiPSEC), Dept. of Physics and Astronomy; Kim, Eunja [Univ. of Nevada, Las Vegas, NV (United States). Dept. of Physics and Astronomy; Cynn, Hyunchae [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Weck, Philippe F [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Seaborg, Kelly [Univ. of Nevada, Las Vegas, NV (United States). High Pressure Science and Engineering Center (HiPSEC), Dept. of Physics and Astronomy; Siska, Emily [Univ. of Nevada, Las Vegas, NV (United States). High Pressure Science and Engineering Center (HiPSEC); Meng, Yue [Carnegie Inst. of Washington, Argonne, IL (United States). Geophysical Lab., High Pressure Collaborative Access Team (HPCAT); Evans, Williams [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2016-06-01

    We report on the experimental and theoretical characterization of a novel GaP polymorph formed by laser heating of a single crystal of GaP-II in its stable region near 43 GPa. Thereby formed unstrained multigrain sample at 43 GPa and 1300 K, allowed high-resolution crystallographic analysis. We find an oS24 as an energetically optimized crystal structure contrary to oS8 reported by Nelmes et al. (1997). Our DFT calculation confirms a stable existence of oS24 between 18 – 50 GPa. The emergence of the oS24 structure is related to the differentiation of phosphorous atoms between those forming P-P dimers and those forming P-Ga bonds only. Bonding anisotropy explains the symmetry lowering with respect to what is generally expected for semiconductors high-pressure polymorphs. The metallization of GaP does not occur through a uniform change of the nature of its bonds but through the formation of an anisotropic phase containing different bond types.

  3. High-throughput screening of metal-porphyrin-like graphenes for selective capture of carbon dioxide

    OpenAIRE

    Hyeonhu Bae; Minwoo Park; Byungryul Jang; Yura Kang; Jinwoo Park; Hosik Lee; Haegeun Chung; ChiHye Chung; Suklyun Hong; Yongkyung Kwon; Boris I. Yakobson; Hoonkyung Lee

    2016-01-01

    Nanostructured materials, such as zeolites and metal-organic frameworks, have been considered to capture CO2. However, their application has been limited largely because they exhibit poor selectivity for flue gases and low capture capacity under low pressures. We perform a high-throughput screening for selective CO2 capture from flue gases by using first principles thermodynamics. We find that elements with empty d orbitals selectively attract CO2 from gaseous mixtures under low CO2 pressures...

  4. 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)

  5. High temperature embrittlement of metals by helium

    International Nuclear Information System (INIS)

    Schroeder, H.

    1983-01-01

    The present knowledge of the influence of helium on the high temperature mechanical properties of metals to be used as structural materials in fast fission and in future fusion reactors is reviewed. A wealth of experimental data has been obtained by many different experimental techniques, on many different alloys, and on different properties. This review is mostly concentrated on the behaviour of austenitic alloys -especially austenitic stainless steels, for which the data base is by far the largest - and gives only a few examples of special bcc alloys. The effect of the helium embrittlement on the different properties - tensile, fatigue and, with special emphasis, creep - is demonstrated by representative results. A comparison between data obtained from in-pile (-beam) experiments and from post-irradiation (-implantation) experiments, respectively, is presented. Theoretical models to describe the observed phenomena are briefly outlined and some suggestions are made for future work to resolve uncertainties and differences between our experimental knowledge and theoretical understanding of high temperature helium embrittlement. (author)

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2017-10-01

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

  7. High pressure sintering (HP-HT) of diamond powders with titanium and titanium carbide

    International Nuclear Information System (INIS)

    Jaworska, L.

    1999-01-01

    Polycrystalline diamond compacts for cutting tools are mostly manufactured using high pressure sintering (HP-HT). The standard diamond compacts are prepared by diamond powders sintering with metallic binding phase. The first group of metallic binder are metals able to solve carbon - Co, Ni. The second group of metal binders are carbide forming elements - Ti, Cr, W and others. The paper describes high pressure sintering of diamond powder with titanium and nonstoichiometry titanium carbide for cutting tool application. A type of binding phase has the significant influence on microstructure and mechanical properties of diamond compacts. Very homogeneous structure was achieved in case of compacts obtained from metalized diamond where diamond-TiC-diamond connection were predominant. In the case of compacts prepared by mechanical mixing of diamond with titanium powders the obtained structure was nonhomogeneous with titanium carbide clusters. They had more diamond to diamond connections. These compacts compared to the compact made of metallized diamond have greater wear resistance. In the case of the diamond and TiC 0.92 sintering the strong bonding of TiC diamond grains was obtained. The microstructure observations for diamond with 5% wt. Ti and diamond with 5% wt. TiC 0.92 (the initial composition) compacts were performed in transmission microscope. For two type of compacts the strong bonding phase TiC without defects is creating. (author)

  8. 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

  9. Robust zero resistance in a superconducting high-entropy alloy at pressures up to 190 GPa

    Science.gov (United States)

    Guo, Jing; Wang, Honghong; von Rohr, Fabian; Wang, Zhe; Cai, Shu; Zhou, Yazhou; Yang, Ke; Li, Aiguo; Jiang, Sheng; Wu, Qi; Cava, Robert J.; Sun, Liling

    2017-12-01

    We report the observation of extraordinarily robust zero-resistance superconductivity in the pressurized (TaNb)0.67(HfZrTi)0.33 high-entropy alloy--a material with a body-centered-cubic crystal structure made from five randomly distributed transition-metal elements. The transition to superconductivity (TC) increases from an initial temperature of 7.7 K at ambient pressure to 10 K at ˜60 GPa, and then slowly decreases to 9 K by 190.6 GPa, a pressure that falls within that of the outer core of the earth. We infer that the continuous existence of the zero-resistance superconductivity from 1 atm up to such a high pressure requires a special combination of electronic and mechanical characteristics. This high-entropy alloy superconductor thus may have a bright future for applications under extreme conditions, and also poses a challenge for understanding the underlying quantum physics.

  10. A survey of repair practices for nuclear power plant containment metallic pressure boundaries

    Energy Technology Data Exchange (ETDEWEB)

    Oland, C.B.; Naus, D.J. [Oak Ridge National Lab., TN (United States)

    1998-05-01

    The Nuclear Regulatory Commission has initiated a program at the Oak Ridge National Laboratory to provide assistance in their assessment of the effects of potential degradation on the structural integrity and leaktightness of metal containment vessels and steel liners of concrete containments in nuclear power plants. One of the program objectives is to identify repair practices for restoring metallic containment pressure boundary components that have been damaged or degraded in service. This report presents issues associated with inservice condition assessments and continued service evaluations and identifies the rules and requirements for the repair and replacement of nonconforming containment pressure boundary components by welding or metal removal. Discussion topics include base and welding materials, welding procedure and performance qualifications, inspection techniques, testing methods, acceptance criteria, and documentation requirements necessary for making acceptable repairs and replacements so that the plant can be returned to a safe operating condition.

  11. A survey of repair practices for nuclear power plant containment metallic pressure boundaries

    International Nuclear Information System (INIS)

    Oland, C.B.; Naus, D.J.

    1998-05-01

    The Nuclear Regulatory Commission has initiated a program at the Oak Ridge National Laboratory to provide assistance in their assessment of the effects of potential degradation on the structural integrity and leaktightness of metal containment vessels and steel liners of concrete containments in nuclear power plants. One of the program objectives is to identify repair practices for restoring metallic containment pressure boundary components that have been damaged or degraded in service. This report presents issues associated with inservice condition assessments and continued service evaluations and identifies the rules and requirements for the repair and replacement of nonconforming containment pressure boundary components by welding or metal removal. Discussion topics include base and welding materials, welding procedure and performance qualifications, inspection techniques, testing methods, acceptance criteria, and documentation requirements necessary for making acceptable repairs and replacements so that the plant can be returned to a safe operating condition

  12. Effects of holding pressure and process temperatures on the mechanical properties of moulded metallic parts

    DEFF Research Database (Denmark)

    Islam, Aminul; Hansen, Hans Nørgaard; Esteves, N.M.

    2013-01-01

    Metal injection moulding is gaining more and more importance over the time and needs more research to be done to understand the sensitivity of process to different process parameters. The current paper makes an attempt to better understand the effects of holding pressure and process temperatures...... on the moulded metallic parts. Stainless steel 316L is used in the investigation to produce the specimen by metal injection moulding (MIM) and multiple analyses were carried out on samples produced with different combinations of holding pressure, mould temperature and melt temperature. Finally, the parts were...... characterized to investigate mechanical properties like density, ultimate tensile strength, shrinkage etc. The results are discussed in the paper. The main conclusion from this study is unlike plastic moulding, the tensile properties of MIM parts doesn’t vary based on the flow direction of the melt, and tensile...

  13. 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)

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

    Energy Technology Data Exchange (ETDEWEB)

    Meissner, Thomas

    2013-05-13

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

  15. 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

  16. High-pressure phases of CuI studied by 129I-Moessbauer spectroscopy

    International Nuclear Information System (INIS)

    Kaindl, G.; Nowik, I.; Frank, K.H.

    1992-01-01

    The results of an 129 I-Moessbauer study of the high-pressure phases of CuI at 4.2 K and for external pressures up to 71 kbar are reported. The isomer shift S and the electric quadrupole interaction E q are found to undergo large discontinuities at the crystallographic phase-transition pressures of ≅18 kbar from zinc-blende to rhombohedral structure and at ≅46 kbar from rhombohedral to tetragonal. The pressure coefficients of these hyperfine parameters are significantly different for the three phases (zinc-blende; rhombohedral; tetragonal): dS/dP=-3.3; =+1.5; =+2.5x10 -3 mm/s/kbar. These results cannot be explained in terms of a simple molecular-orbital picture; instead, they reflect pressure-induced variations of the halogen-p/metal-d hybridization in the valence bands of the various phases of CuI. (orig.)

  17. 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...

  18. 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.

  19. 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 ...

  20. 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 ...

  1. 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 ...

  2. 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 ...

  3. 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

  4. Pressure-induced magnetic collapse and metallization of TlF e1.6S e2

    Science.gov (United States)

    Naumov, P. G.; Filsinger, K.; Shylin, S. I.; Barkalov, O. I.; Ksenofontov, V.; Qi, Y.; Palasyuk, T.; Schnelle, W.; Medvedev, S. A.; Greenblatt, M.; Felser, C.

    2017-08-01

    The crystal structure, magnetic ordering, and electrical resistivity of TlF e1.6S e2 were studied at high pressures. Below ˜7 GPa , TlF e1.6S e2 is an antiferromagnetically ordered semiconductor with a ThC r2S i2 -type structure. The insulator-to-metal transformation observed at a pressure of ˜7 GPa is accompanied by a loss of magnetic ordering and an isostructural phase transition. In the pressure range ˜7.5 -11 GPa a remarkable downturn in resistivity, which resembles a superconducting transition, is observed below 15 K. We discuss this feature as the possible onset of superconductivity originating from a phase separation in a small fraction of the sample in the vicinity of the magnetic transition.

  5. 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.

  6. 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.

  7. 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.

  8. High power diode laser remelting of metals

    International Nuclear Information System (INIS)

    Chmelickova, H; Tomastik, J; Ctvrtlik, R; Supik, J; Nemecek, S; Misek, M

    2014-01-01

    This article is focused on the laser surface remelting of the steel samples with predefined overlapping of the laser spots. The goal of our experimental work was to evaluate microstructure and hardness both in overlapped zone and single pass ones for three kinds of ferrous metals with different content of carbon, cast iron, non-alloy structural steel and tool steel. High power fibre coupled diode laser Laserline LDF 3600-100 was used with robotic guided processing head equipped by the laser beam homogenizer that creates rectangular beam shape with uniform intensity distribution. Each sample was treated with identical process parameters - laser power, beam diameter, focus position, speed of motion and 40% spot overlap. Dimensions and structures of the remelted zone, zone of the partial melting, heat affected zone and base material were detected and measured by means of laser scanning and optical microscopes. Hardness progress in the vertical axis of the overlapped zone from remelted surface layer to base material was measured and compared with the hardness of the single spots. The most hardness growth was found for cast iron, the least for structural steel. Experiment results will be used to processing parameters optimization for each tested material separately.

  9. 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.

  10. Metallic substrates for high temperature superconductors

    Science.gov (United States)

    Truchan, Thomas G.; Miller, Dean J.; Goretta, Kenneth C.; Balachandran, Uthamalingam; Foley, Robert

    2002-01-01

    A biaxially textured face-centered cubic metal article having grain boundaries with misorientation angles greater than about 8.degree. limited to less than about 1%. A laminate article is also disclosed having a metal substrate first rolled to at least about 95% thickness reduction followed by a first annealing at a temperature less than about 375.degree. C. Then a second rolling operation of not greater than about 6% thickness reduction is provided, followed by a second annealing at a temperature greater than about 400.degree. C. A method of forming the metal and laminate articles is also disclosed.

  11. High Precision Metal Thin Film Liftoff Technique

    Science.gov (United States)

    Brown, Ari D. (Inventor); Patel, Amil A. (Inventor)

    2015-01-01

    A metal film liftoff process includes applying a polymer layer onto a silicon substrate, applying a germanium layer over the polymer layer to create a bilayer lift off mask, applying a patterned photoresist layer over the germanium layer, removing an exposed portion of the germanium layer, removing the photoresist layer and a portion of the polymer layer to expose a portion of the substrate and create an overhanging structure of the germanium layer, depositing a metal film over the exposed portion of the substrate and the germanium layer, and removing the polymer and germanium layers along with the overlaying metal film.

  12. Preparation of high-pressure phase boron nitride films by physical vapor deposition

    CERN Document Server

    Zhu, P W; Zhao, Y N; Li, D M; Liu, H W; Zou Guang Tian

    2002-01-01

    The high-pressure phases boron nitride films together with cubic, wurtzic, and explosive high-pressure phases, were successfully deposited on the metal alloy substrates by tuned substrate radio frequency magnetron sputtering. The percentage of cubic boron nitride phase in the film was about 50% as calculated by Fourier transform infrared measurements. Infrared peak position of cubic boron nitride at 1006.3 cm sup - sup 1 , which is close to the stressless state, indicates that the film has very low internal stress. Transition electron microscope micrograph shows that pure cubic boron nitride phase exits on the surface of the film. The growth mechanism of the BN films was also discussed.

  13. 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.

  14. 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...

  15. Liquid metal reactor/Pressurized water reactor plant comparison study

    International Nuclear Information System (INIS)

    Halverson, T.G.

    1986-01-01

    The selection between alternative electric power generating technologies is mainly based on their overall economics. Capital costs account for over 60% of the total busbar cost of nuclear plants. Estimates reported in the literature have shown capital cost ratios of LMRs to PWRs ranging from less than 1 to as high as 1.8. To reduce this range of uncertainty, the study selected a method for cataloging plant hardware and then performed comparisons using engineering judgment as to the anticipated and reasonable cost differences. The paper summarizes the resulting one-on-one comparisons of components, systems, and buildings and identifies the LMR-PWR similarities and differences which influence costs. The study leads to the conclusion that the capital cost of the most up-to-date large LMR design would be very close to that of the latest PWRs

  16. 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

  17. Development of loose part signal location estimating technique in high pressured structure

    Energy Technology Data Exchange (ETDEWEB)

    Rhee, Ill Keun; Choi, Jae Won; Kim, Yong Up; Kim, Taek Hwan; Song, Young Joong [Hannam University, Taejon (Korea, Republic of)

    1997-07-01

    The main purpose of this project is to develop the metallic loose parts monitoring and diagnosis technology. This will contribute to the development of the domestic technology, and, at the some time, to the development of related domestic industries. This study has been performed as 3-year-project,= to provide to basic requirements in developing the integrated and intelligent loose part monitoring and diagnosis system for Reactor Pressure Vessel (RPV). The results from this project is expected to be applied to the development of the integrated and intelligent loose part monitoring and diagnosis system which can be used to analyze the main cause of the malfunctioning of the system under the worst circumstance - high temperature, high pressure and high speed of the flow of reactor coolant, with the efficient software package that could classify the characteristics of the metallic loose parts occurred inside the RPV of the nuclear steam supply system. (Author) 39 refs., 7 tabs., 74 figs.

  18. 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.)

  19. 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.

  20. 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