WorldWideScience

Sample records for single high pressure

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2013-11-01

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

  2. Raman study of bromine-doped single-walled carbon nanotubes under high pressure

    CERN Document Server

    Liu Bing Bing; Yu Miao; Zou Guang Tian; Carlsten, J; Wagberg, T; Sundqvist, B

    2002-01-01

    Raman results for different single-walled carbon nanotube bundles doped with Br sub 2 were studied both at ambient pressure and under high pressure up to 6 GPa. Our study indicates that bromine resides in the interstitial channel of nanotube bundles as a form of polymer.

  3. High-pressure catalytic reactions over single-crystal metal surfaces

    Science.gov (United States)

    Rodriguez, JoséA.; Wayne Goodman, D.

    1991-11-01

    Studies dealing with high-pressure catalytic reactions over single-crystal surfaces are reviewed. The coupling of an apparatus for the measurement of reaction kinetics at elevated pressures with an ultrahigh vacuum system for surface analysis allows detailed study of structure sensitivity, the effects of promoters and inhibitors on catalytic activity, and, in certain cases, identification of reaction intermediates by post-reaction surface analysis. Examples are provided which demonstrate the relevance of single-crystal studies for modeling the behaviour of high-surface-area supported catalysts. Studies of CO methanation and CO oxidation over single-crystal surfaces provide convincing evidence that these reactions are structure insensitive. For structure-sensitive reactions (ammonia synthesis, alkane hydrogenolysis, alkane isomerization, water-gas shift reaction, etc.) model single-crystal studies allow correlations to be established between surface structure and catalytic activity. The effects of both electronegative (S and P) and electropositive (alkali metals) impurities upon the catalytic activity of metal single crystals for ammonia synthesis, CO methanation, alkane hydrogenolysis, ethylene epoxidation and water-gas shift are discussed. The roles of "ensemble" and "ligand" effects in bimetallic catalysts are examined in light of data obtained using surfaces prepared by vapor-depositing one metal onto a crystal face of a dissimilar metal.

  4. High-pressure oxygenation of thin-wall YBCO single-domain samples

    International Nuclear Information System (INIS)

    Chaud, X; Savchuk, Y; Sergienko, N; Prikhna, T; Diko, P

    2008-01-01

    The oxygen annealing of ReBCO bulk material, necessary to achieve superconducting properties, usually induces micro- and macro-cracks. This leads to a crack-assisted oxygenation process that allows oxygenating large bulk samples faster than single crystals. But excellent superconducting properties are cancelled by the poor mechanical ones. More progressive oxygenation strategy has been shown to reduce drastically the oxygenation cracks. The problem then arises to keep a reasonable annealing time. The concept of bulk Y123 single-domain samples with thin-wall geometry has been introduced to bypass the inherent limitation due to a slow oxygen diffusion rate. But it is not enough. The use of a high oxygen pressure (16 MPa) enables to speed up further the process. It introduces a displacement in the equilibrium phase diagram towards higher temperatures, i.e., higher diffusion rates, to achieve a given oxygen content in the material. Remarkable results were obtained by applying such a high pressure oxygen annealing process on thin-wall single-domain samples. The trapped field of 16 mm diameter Y123 thin-wall single-domain samples was doubled (0.6T vs 0.3T at 77K) using an annealing time twice shorter (about 3 days). The initial development was made on thin bars. The advantage of thin-wall geometry is that such an annealing can be applied directly to a much larger sample

  5. High pressure effect on MoS2 and MoSe2 single crystals grown by ...

    Indian Academy of Sciences (India)

    Unknown

    The variation of electrical resistance under pressure was monitored in a Bridgman anvil set-up up to 6⋅5 GPa to identify occurrence of any structural transition. MoS2 and MoSe2 do not undergo any structural transitions under pressure. Keywords. Single crystals; chemical vapour transport technique; high pressure. 1.

  6. Single-crystal neutron diffraction under high pressures: valence instabilities in Tm monochalcogenides

    International Nuclear Information System (INIS)

    Mignot, J.-M.; Goncharenko, I.N.; Link, P.; Matsumura, T.; Suzuki, T.

    2000-01-01

    New high-pressure devices based on the use of sapphire anvils now allow single-crystal neutron diffraction experiments to be performed up to P=8-10 GPa. After giving a brief overview of the technique, we present its application to the study of pressure-induced valence instabilities in Tm monochalcogenides (TmX, X: S, Se, Te). A variety of new magnetic phases have been characterized, yielding a consistent picture of the evolution of magnetism through the series. The results indicate a striking interplay between magnetic order taking place at low temperature and different types of electronic ground states (classical semiconductor, narrow-gap Kondo insulator, metallic Kondo lattice, etc.) inferred from the transport properties

  7. Engine with hydraulic fuel injection and ABS circuit using a single high pressure pump

    Science.gov (United States)

    Bartley, Bradley E.; Blass, James R.; Gibson, Dennis H.

    2001-01-01

    An engine system comprises a hydraulically actuated fuel injection system and an ABS circuit connected via a fluid flow passage that provides hydraulic fluid to both the fuel injection system and to the ABS circuit. The hydraulically actuated system includes a high pressure pump. The fluid control passage is in fluid communication with an outlet from the high pressure pump.

  8. Development of technique for high-pressure single-crystal neutron scattering and its application to studies of magnetic materials

    International Nuclear Information System (INIS)

    Osakabe, Toyotake

    2012-01-01

    In this article, a new high-pressure apparatus for single-crystal magnetic neutron diffraction under 10 GPa is described. First, new hybrid-anvil, which is composed of an opposed pair of a supported SiC anvil and a tungsten carbide (WC) anvil with a center-dimpled culet, is introduced. Next, results of an investigation of pressure-transmitting media are shown. The hydrostaticity of the media is essential for the single-crystal diffraction experiments. Finally, a thermal neutron focusing device with a lot of curved supermirrors is shown. The device can compensate weak magnetic signals from tiny samples in high-pressure cells. As examples of the studies using the apparatus, the high-pressure single-crystal magnetic neutron diffraction experiments on 4f-electron systems PrFe 4 P 12 and HoB 2 C 2 are taken up. (author)

  9. Inclusions related to catalyst and medium for transmitting pressure in diamond single crystals grown at high temperature and high pressure from the Fe-C system

    International Nuclear Information System (INIS)

    Yin Longwei; Li Musen; Hao Zhaoyin; Zhang Jiongfa

    2001-01-01

    Inclusion entrapment in a crystal is one of the most important characteristics for the crystal growth technique from solution. Diamond single crystals grown from the Fe-C system at high temperature-high pressure usually contain inclusions related to the molten catalyst and the medium (pyrophyllite) for transmitting pressure. During the growth of the diamond, the inclusions are trapped by the growth front or are formed through reaction between the contaminants trapped in the diamond. In the present article, the inclusions related to the catalyst and pyrophyllite were systemically examined by transmission electron microscopy. The chemical composition and crystal structure of the inclusions were, for the first time, determined by selected area electron diffraction pattern combined with energy dispersive x-ray spectrometry. It was shown that the inclusions are mainly composed of orthorhombic Fe 3 C, orthorhombic FeSi 2 , hexagonal SiO 2 and face-centred cubic SiC. (author)

  10. Vehicle having hydraulic and power steering systems using a single high pressure pump

    Science.gov (United States)

    Bartley, Bradley E.; Blass, James R.; Gibson, Dennis H.

    2001-06-22

    A vehicle comprises a plurality of wheels attached to a vehicle housing. Also attached to the vehicle housing is a power steering system, including a fluid flow circuit, which is operably coupled to a number of the wheels. An internal combustion engine attached to the vehicle housing is connected to a hydraulically actuated system that includes a high pressure pump. An outlet of the high pressure pump is in fluid communication with the fluid flow circuit.

  11. Single crystal growth, characterization and high-pressure Raman spectroscopy of impurity-free magnesite (MgCO3)

    Science.gov (United States)

    Liang, Wen; Li, Zeming; Yin, Yuan; Li, Rui; Chen, Lin; He, Yu; Dong, Haini; Dai, Lidong; Li, Heping

    2017-11-01

    The understanding of the physical and chemical properties of magnesite (MgCO3) under deep-mantle conditions is highly important to capture the essence of deep-carbon storage in Earth's interior. To develop standard rating scales, the impurity-free magnesite single crystal, paying particular attention to the case of avoiding adverse impacts of Ca2+, Fe2+, and Mn2+ impurities in natural magnesite, is undoubtedly necessary for all research of magnesite, including crystalline structural phase transitions, anisotropic elasticity and conductivity, and equation of state (EoS). Thus, a high-quality single crystal of impurity-free magnesite was grown successfully for the first time using the self-flux method under high pressure-temperature conditions. The size of the magnesite single crystal, observed in a plane-polarized microscope, exceeds 200 μm, and the crystal exhibits a rhombohedral structure to cleave along the (101) plane. In addition, its composition of Mg0.999 ± 0.001CO3 was quantified through electron probing analysis. The structural property was investigated by means of single crystal X-ray diffraction and the unit cell dimensions obtained in the rhombohedral symmetry of the R\\bar {3}c space group are a = 4.6255 (3) and c = 14.987 (2), and the final R = 0.0243 for 718 reflections. High-pressure Raman spectroscopy of the magnesite single crystal was performed up to 27 GPa at ambient temperature. All Raman active bands, ν i, without any splitting increased almost linearly with increasing pressure. In combination with the high-pressure Raman results {{d/ν _i}}{{{d}P}} and the bulk modulus K T (103 GPa) reported from magnesite EoS studies, the mode Grüneisen parameters (1.49, 1.40, 0.26, and 0.27) of each vibration (T, L, ν 4, and ν 1) were calculated.

  12. Preparation and characterization of single crystal samples for high-pressure experiments

    Energy Technology Data Exchange (ETDEWEB)

    Farber, D; Antonangeli, D; Aracne, C; Benterou, J

    2005-10-26

    To date, most research utilizing the diamond anvil cell (DAC) has been conducted with polycrystalline samples, thus the results are limited to addressing average bulk properties. However, experiments on single crystals can yield data on a range of orientation dependent properties such as thermal and electrical conductivity, magnetic susceptibility, elasticity and plasticity. Here we report new procedures to produce extremely high-quality metallic single crystal samples of size compatible with DAC experiments in the Mbar range. So far, we have produced samples of zinc, Al{sub 2}O{sub 3}, cobalt, molybdenum and cerium, and have evaluated the quality of the finished samples with white-light interferometry, synchrotron x-ray diffraction and inelastic x-ray scattering.

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

    International Nuclear Information System (INIS)

    Imoto, Yuji; Yan, Jiwang

    2017-01-01

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

  14. High pressure effect on MoS2 and MoSe2 single crystals grown by ...

    Indian Academy of Sciences (India)

    Unknown

    tetrahedral anvil apparatus up to 5 GPa. In this paper we report room temperature resistance mea- surements as a function of pressure on MoS2 and MoSe2 single crystals. In each case the resistance decreases un- der pressure due to an increase in the carrier concentration. 2. Experimental. Single crystals of MoS2 and ...

  15. 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 high ... weight. How Will I Know if I Have High Blood Pressure? High blood pressure is a silent problem — you ...

  16. Probing high pressure properties of single wall carbon nanotubes through fullerene encapsulation

    Czech Academy of Sciences Publication Activity Database

    Cailier, Ch.; Machon, D.; San-Miguel, A.; Arenal, R.; Montagnac, G.; Cardon, H.; Kalbáč, Martin; Zukalová, Markéta; Kavan, Ladislav

    2008-01-01

    Roč. 77, č. 12 (2008), , 125418-1-9 ISSN 1098-0121 R&D Projects: GA MŠk LC510 Institutional research plan: CEZ:AV0Z40400503 Keywords : Raman spectroscopy * hydrostatic-pressure * transmitting medium * phase-transition Subject RIV: CG - Electrochemistry Impact factor: 3.322, year: 2008

  17. 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 ...

  18. 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 ...

  19. Use of a miniature diamond-anvil cell in high-pressure single-crystal neutron Laue diffraction.

    Science.gov (United States)

    Binns, Jack; Kamenev, Konstantin V; McIntyre, Garry J; Moggach, Stephen A; Parsons, Simon

    2016-05-01

    The first high-pressure neutron diffraction study in a miniature diamond-anvil cell of a single crystal of size typical for X-ray diffraction is reported. This is made possible by modern Laue diffraction using a large solid-angle image-plate detector. An unexpected finding is that even reflections whose diffracted beams pass through the cell body are reliably observed, albeit with some attenuation. The cell body does limit the range of usable incident angles, but the crystallographic completeness for a high-symmetry unit cell is only slightly less than for a data collection without the cell. Data collections for two sizes of hexamine single crystals, with and without the pressure cell, and at 300 and 150 K, show that sample size and temperature are the most important factors that influence data quality. Despite the smaller crystal size and dominant parasitic scattering from the diamond-anvil cell, the data collected allow a full anisotropic refinement of hexamine with bond lengths and angles that agree with literature data within experimental error. This technique is shown to be suitable for low-symmetry crystals, and in these cases the transmission of diffracted beams through the cell body results in much higher completeness values than are possible with X-rays. The way is now open for joint X-ray and neutron studies on the same sample under identical conditions.

  20. Use of a miniature diamond-anvil cell in high-pressure single-crystal neutron Laue diffraction

    Directory of Open Access Journals (Sweden)

    Jack Binns

    2016-05-01

    Full Text Available The first high-pressure neutron diffraction study in a miniature diamond-anvil cell of a single crystal of size typical for X-ray diffraction is reported. This is made possible by modern Laue diffraction using a large solid-angle image-plate detector. An unexpected finding is that even reflections whose diffracted beams pass through the cell body are reliably observed, albeit with some attenuation. The cell body does limit the range of usable incident angles, but the crystallographic completeness for a high-symmetry unit cell is only slightly less than for a data collection without the cell. Data collections for two sizes of hexamine single crystals, with and without the pressure cell, and at 300 and 150 K, show that sample size and temperature are the most important factors that influence data quality. Despite the smaller crystal size and dominant parasitic scattering from the diamond-anvil cell, the data collected allow a full anisotropic refinement of hexamine with bond lengths and angles that agree with literature data within experimental error. This technique is shown to be suitable for low-symmetry crystals, and in these cases the transmission of diffracted beams through the cell body results in much higher completeness values than are possible with X-rays. The way is now open for joint X-ray and neutron studies on the same sample under identical conditions.

  1. Use of a miniature diamond-anvil cell in high-pressure single-crystal neutron Laue diffraction

    Science.gov (United States)

    Binns, Jack; Kamenev, Konstantin V.; McIntyre, Garry J.; Moggach, Stephen A.; Parsons, Simon

    2016-01-01

    The first high-pressure neutron diffraction study in a miniature diamond-anvil cell of a single crystal of size typical for X-ray diffraction is reported. This is made possible by modern Laue diffraction using a large solid-angle image-plate detector. An unexpected finding is that even reflections whose diffracted beams pass through the cell body are reliably observed, albeit with some attenuation. The cell body does limit the range of usable incident angles, but the crystallographic completeness for a high-symmetry unit cell is only slightly less than for a data collection without the cell. Data collections for two sizes of hexamine single crystals, with and without the pressure cell, and at 300 and 150 K, show that sample size and temperature are the most important factors that influence data quality. Despite the smaller crystal size and dominant parasitic scattering from the diamond-anvil cell, the data collected allow a full anisotropic refinement of hexamine with bond lengths and angles that agree with literature data within experimental error. This technique is shown to be suitable for low-symmetry crystals, and in these cases the transmission of diffracted beams through the cell body results in much higher completeness values than are possible with X-rays. The way is now open for joint X-ray and neutron studies on the same sample under identical conditions. PMID:27158503

  2. A rotator for single-crystal neutron diffraction at high pressure.

    Science.gov (United States)

    Fang, J; Bull, C L; Hamidov, H; Loveday, J S; Gutmann, M J; Nelmes, R J; Kamenev, K V

    2010-11-01

    We present a modified Paris-Edinburgh press which allows rotation of the anvils and the sample under applied load. The device is designed to overcome the problem of having large segments of reciprocal space obscured by the tie rods of the press during single-crystal neutron-scattering experiments. The modified press features custom designed hydraulic bearings and provides controls for precision rotation and positioning. The advantages of using the device for increasing the number of measurable reflections are illustrated with the results of neutron-diffraction experiments on a single crystal of germanium rotated under a load of 70 tonnes.

  3. Special structures and properties of hydrogen nanowire confined in a single walled carbon nanotube at extreme high pressure

    Directory of Open Access Journals (Sweden)

    Yueyuan Xia

    2012-06-01

    Full Text Available Extensive ab initio molecular dynamics simulations indicate that hydrogen can be confined in single walled carbon nanotubes to form high density and high pressure H2 molecular lattice, which has peculiar shell and axial structures depending on the density or pressure. The band gap of the confined H2 lattice is sensitive to the pressure. Heating the system at 2000K, the H2 lattice is firstly melted to form H2 molecular liquid, and then some of the H2 molecules dissociate accompanied by drastic molecular and atomic reactions, which have essential effect on the electronic structure of the hydrogen system. The liquid hydrogen system at 2000K is found to be a particular mixed liquid, which consists of H2 molecules, H atoms, and H-H-H trimers. The dissociated H atoms and the trimers in the liquid contribute resonance electron states at the Fermi energy to change the material properties substantially. Rapidly cooling the system from 2000K to 0.01 K, the mixed liquid is frozen to form a mixed solid melt with a clear trend of band gap closure. It indicates that this solid melt may become a superconducting nanowire when it is further compressed.

  4. Molecular-dynamic simulations of the thermophysical properties of hexanitrohexaazaisowurtzitane single crystal at high pressures and temperatures

    Science.gov (United States)

    Kozlova, S. A.; Gubin, S. A.; Maklashova, I. V.; Selezenev, A. A.

    2017-11-01

    Molecular dynamic simulations of isothermal compression parameters are performed for a hexanitrohexaazaisowurtzitane single crystal (C6H6O12N12) using a modified ReaxFF-log reactive force field. It is shown that the pressure-compression ratio curve for a single C6H6O12N12 crystal at constant temperature T = 300 K in pressure range P = 0.05-40 GPa is in satisfactory agreement with experimental compression isotherms obtained for a single C6H6O12N12 crystal. Hugoniot molecular-dynamic simulations of the shock-wave hydrostatic compression of a single C6H6O12N12 crystal are performed. Along with Hugoniot temperature-pressure curves, calculated shock-wave pressure-compression ratios for a single C6H6O12N12 crystal are obtained for a wide pressure range of P = 1-40 GPa. It is established that the percussive adiabat obtained for a single C6H6O12N12 crystal is in a good agreement with the experimental data. All calculations are performed using a LAMMPS molecular dynamics simulation software package that provides a ReaxFF-lg reactive force field to support the approach.

  5. High-pressure single-crystal neutron scattering study of magnetic and Fe vacancy orders in (Tl,Rb)2Fe4Se5 superconductor

    OpenAIRE

    Ye, Feng; Bao, Wei; Chi, Songxue; Santos, Antonio M. dos; Molaison, Jamie J.; Fang, Minghu; Wang, Hangdong; Wang, Qianhui Mao Jinchen; Liu, Juanjuan; Sheng, Jieming

    2014-01-01

    The magnetic and iron vacancy orders in superconducting (Tl,Rb)2Fe4Se5 single-crystals are investigated by using a high-pressure neutron diffraction technique. Similar to the temperature effect, the block antiferromagnetic order gradually decreases upon increasing pressure while the Fe vacancy superstructural order remains intact before its precipitous disappearance at the critical pressure Pc = 8.3 GPa. Combined with previously determined Pc for superconductivity, our phase diagram under pre...

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

    Science.gov (United States)

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

    2013-09-01

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

  7. 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, ...

  8. 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 ...

  9. 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 ...

  10. High blood pressure - infants

    Science.gov (United States)

    Hypertension - infants ... and blood vessels The health of the kidneys High blood pressure in infants may be due to kidney or ... blood vessel of the kidney) In newborn babies, high blood pressure is often caused by a blood clot in ...

  11. 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...

  12. Tunable high pressure lasers

    Science.gov (United States)

    Hess, R. V.

    1976-01-01

    Atmospheric transmission of high energy CO2 lasers is considerably improved by high pressure operation which, due to pressure broadening, permits tuning the laser lines off atmospheric absorption lines. Pronounced improvement is shown for horizontal transmission at altitudes above several kilometers and for vertical transmission through the entire atmosphere. Applications of tunable high pressure CO2 lasers to energy transmission and to remote sensing are discussed along with initial efforts in tuning high pressure CO2 lasers.

  13. Highly wearable cuff-less blood pressure and heart rate monitoring with single-arm electrocardiogram and photoplethysmogram signals.

    Science.gov (United States)

    Zhang, Qingxue; Zhou, Dian; Zeng, Xuan

    2017-02-06

    Long-term continuous systolic blood pressure (SBP) and heart rate (HR) monitors are of tremendous value to medical (cardiovascular, circulatory and cerebrovascular management), wellness (emotional and stress tracking) and fitness (performance monitoring) applications, but face several major impediments, such as poor wearability, lack of widely accepted robust SBP models and insufficient proofing of the generalization ability of calibrated models. This paper proposes a wearable cuff-less electrocardiography (ECG) and photoplethysmogram (PPG)-based SBP and HR monitoring system and many efforts are made focusing on above challenges. Firstly, both ECG/PPG sensors are integrated into a single-arm band to provide a super wearability. A highly convenient but challenging single-lead configuration is proposed for weak single-arm-ECG acquisition, instead of placing the electrodes on the chest, or two wrists. Secondly, to identify heartbeats and estimate HR from the motion artifacts-sensitive weak arm-ECG, a machine learning-enabled framework is applied. Then ECG-PPG heartbeat pairs are determined for pulse transit time (PTT) measurement. Thirdly, a PTT&HR-SBP model is applied for SBP estimation, which is also compared with many PTT-SBP models to demonstrate the necessity to introduce HR information in model establishment. Fourthly, the fitted SBP models are further evaluated on the unseen data to illustrate the generalization ability. A customized hardware prototype was established and a dataset collected from ten volunteers was acquired to evaluate the proof-of-concept system. The semi-customized prototype successfully acquired from the left upper arm the PPG signal, and the weak ECG signal, the amplitude of which is only around 10% of that of the chest-ECG. The HR estimation has a mean absolute error (MAE) and a root mean square error (RMSE) of only 0.21 and 1.20 beats per min, respectively. Through the comparative analysis, the PTT&HR-SBP models significantly outperform

  14. 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

  15. High-pressure single-crystal X-ray diffraction of Tl2SeO4

    International Nuclear Information System (INIS)

    Grzechnik, Andrzej; Breczewski, Tomasz; Friese, Karen

    2008-01-01

    The effect of pressure on the crystal structure of thallium selenate (Tl 2 SeO 4 ) (Pmcn, Z=4), containing the Tl + cations with electron lone pairs, has been studied with single-crystal X-ray diffraction in a diamond anvil cell up to 3.64 GPa at room temperature. No phase transition has been observed. The compressibility data are fitted by a Murnaghan equation of state with the zero-pressure bulk modulus B 0 =29(1) GPa and the unit-cell volume at ambient pressure V 0 =529.6(8) A 3 (B'=4.00). Tl 2 SeO 4 is the least compressible in the c direction, while the pressure-induced changes of the a and b lattice parameters are quite similar. These observations can be explained by different pressure effects on the nine- and 11-fold coordination polyhedra around the two non-equivalent Tl atoms. The SeO 4 2- tetrahedra are not rigid units and become more distorted. Their contribution to the compressibility is small. The effect of pressure on the isotypical oxide materials A 2 TO 4 with the β-K 2 SO 4 structure is discussed. It appears that the presence of electron lone pairs on the Tl + cation does not seem to influence the compressibility of Tl 2 SeO 4 . - Graphical abstract: Pressure dependence of normalized lattice parameters and unit-cell volumes in Tl 2 SeO 4 (Pmcn, Z=4). The solid line is the Murnaghan equation of state

  16. High Blood Pressure

    Science.gov (United States)

    ... effects on blood pressure. Finding out what genetic patterns contribute to high blood pressure risk. NHLBI-funded researchers identified dozens of ... whether a low-sodium and low-calorie eating pattern, along with aerobic exercise, can improve blood pressure in patients who do not respond to ...

  17. Helimagnetism of Fe: High pressure study of an Y.sub.2./sub.Fe.sub.17./sub. single crystal

    Czech Academy of Sciences Publication Activity Database

    Prokhnenko, Olexandr; Kamarád, Jiří; Prokeš, K.; Arnold, Zdeněk; Andreev, Alexander V.

    2005-01-01

    Roč. 94, - (2005), 107201/1-107201/4 ISSN 0031-9007 R&D Projects: GA ČR(CZ) GP202/04/P014 Institutional research plan: CEZ:AV0Z10100521 Keywords : high pressures * iron * magnetic structures * neutron diffraction * helimagnetic structure Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 7.489, year: 2005

  18. High temperature pressure gauge

    Science.gov (United States)

    Echtler, J. Paul; Scandrol, Roy O.

    1981-01-01

    A high temperature pressure gauge comprising a pressure gauge positioned in fluid communication with one end of a conduit which has a diaphragm mounted in its other end. The conduit is filled with a low melting metal alloy above the diaphragm for a portion of its length with a high temperature fluid being positioned in the remaining length of the conduit and in the pressure gauge.

  19. Uniaxial-pressure dependence of the magnetization dynamics in the high-symmetry single-molecule magnet Mn12-MeOH

    Science.gov (United States)

    Atkinson, James H.; Bhaskaran, Lakshmi; Hill, Stephen; Myasoedov, Yuri; Zeldov, Eli; Del Barco, Enrique; Friedman, Jonathan; Fournet, Adeline; Christou, George

    2015-03-01

    The single-molecule magnet [Mn12O12(O2CCH3)16(CH3OH)4]CH3OH (``Mn12-MeOH'') is a high-symmetry sibling of the Mn12-Acetate SMM that offers a prime opportunity to explore the consequences of molecular symmetry. A previous study has shown that applied pressure induced changes in the Mn12-Acetate's anisotropy parameters. Here we present the results of a study in which uniaxial pressure was applied to a crystalline sample of Mn12-MeOH in order to examine how the pressure affects the quantum tunneling of magnetization at low temperature. We find that the pressure induces an increase in the resonant tunneling rate manifested as a change in the height of the tunneling steps in the magnetic hysteresis. These results suggest that pressure is altering symmetry-breaking terms in the molecule's spin Hamiltonian, giving rise to increased tunneling.

  20. 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 ...

  1. 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.

  2. High-pressure crystallography.

    Science.gov (United States)

    McMahon, Malcolm I

    2012-01-01

    The ability of pressure to change inter-atomic distances strongly leads to a wide range of pressure-induced phenomena at high pressures: for example metallisation, amorphisation, superconductivity and polymerisation. Key to understanding these phenomena is the determination of the crystal structure using x-ray or neutron diffraction. The tools necessary to compress matter above 1 million atmospheres (1 Megabar or 100 GPa) were established by the mid 1970s, but it is only since the early 1990s that we have been able to determine the detailed crystal structures of materials at such pressures. In this chapter I briefly review the history of high-pressure crystallography, and describe the techniques used to obtain and study materials at high pressure. Recent crystallographic studies of elements are then used to illustrate what is now possible using modern detectors and synchrotron sources. Finally, I speculate as to what crystallographic studies might become possible over the next decade.

  3. High-pressure apparatus

    OpenAIRE

    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 are oriented in the peripheral direction and are embedded in a matrix of epoxy resin or polyurethane. By applying the axial prestress to the pressure vessel (3), the tangential stress is distribut...

  4. High-pressure microfluidics

    Science.gov (United States)

    Hjort, K.

    2015-03-01

    When using appropriate materials and microfabrication techniques, with the small dimensions the mechanical stability of microstructured devices allows for processes at high pressures without loss in safety. The largest area of applications has been demonstrated in green chemistry and bioprocesses, where extraction, synthesis and analyses often excel at high densities and high temperatures. This is accessible through high pressures. Capillary chemistry has been used since long but, just like in low-pressure applications, there are several potential advantages in using microfluidic platforms, e.g., planar isothermal set-ups, large local variations in geometries, dense form factors, small dead volumes and precisely positioned microstructures for control of reactions, catalysis, mixing and separation. Other potential applications are in, e.g., microhydraulics, exploration, gas driven vehicles, and high-pressure science. From a review of the state-of-art and frontiers of high pressure microfluidics, the focus will be on different solutions demonstrated for microfluidic handling at high pressures and challenges that remain.

  5. High Blood Pressure

    Science.gov (United States)

    ... can help you control high blood pressure. These habits include: Healthy eating Being physically active Maintaining a healthy weight Limiting alcohol intake Managing and coping with stress To help make lifelong lifestyle changes, try making ...

  6. Hypertension (High Blood Pressure)

    Science.gov (United States)

    ... Add less salt to your food and avoid fast food and other foods that are high in salt. Know your blood pressure and have it ... a Health Problem Cholesterol Smart Snacking Yoga for Stress Relief ...

  7. 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

  8. High-pressure single-crystal neutron diffraction (to 20 kbar) using a pulsed source: Preliminary investigation of Tl3PSe4

    International Nuclear Information System (INIS)

    Alkire, R.W.; Larson, A.C.; Vergamini, P.J.; Schirber, J.E.; Morosin, B.

    1985-01-01

    A new technique is described for performing high-pressure single-crystal neutron diffraction [up to 20 kbar (2GPa) at room temperature], using a BeCu pressure cell, an area detector and the Los Alamos National Laboratory pulsed neutron source. Success of this method depends on the increase in information available with a multi-wavelength pulse neutron source, a novel orientation of a cylindrically symmetric pressure cell with its axis coincident with the neutron beam and a specific crystal orientation within the pressure cell. Bragg scattering from the pressure cell is avoided and background for a given 2theta is constant. For a crystal of orthorhombic or higher symmetry oriented with the incident beam passing midway between the major lattice vectors, it will be possible to refine a complete three-dimensional structure with data collected from only one pressure loading. Preliminary investigations of Tl 3 PSe 4 lattice parameters (space group Pcmn) at 15(1)kbar yielded linear compressibilities (. 1000 in kbar -1 ) of Ksub(a) = 1.05(8), Ksub(b) = 1.50(10), Ksub(c) = 1.20(8). The anisotropic compressibility is explained by examination of the ambient-pressure room-temperature structure. (orig.)

  9. Diagnosis of High Blood Pressure

    Medline Plus

    Full Text Available ... Card can help you track your blood pressure. Pregnancy Planning High blood pressure can cause problems for ... control your blood pressure before and during the pregnancy. Some women develop high blood pressure during pregnancy. ...

  10. Superconductivity under high pressure

    Energy Technology Data Exchange (ETDEWEB)

    Amaya, K.; Shimizu, K.; Takeda, K.; Tateiwa, N.; Muramatsu, T.; Ishizuka, M.; Kobayashi, T.C

    2003-05-01

    In part 1, we review techniques developed in our laboratory for producing the complex extreme condition of very low temperature and ultra-high pressure and those for measuring electrical resistance and magnetization of the sample confined in the extremely small space of the used pressure cell. In part 2, we review our experimental results in search for pressure-induced superconductivity, which have been obtained by the use of developed techniques. Typical examples are shown in the case of simple inorganic and organic molecular crystals, ionic crystals, and magnetic metals.

  11. High pressure induced superconductivity

    Energy Technology Data Exchange (ETDEWEB)

    Amaya, K.; Shimizu, K

    2003-10-15

    We have developed complex extreme condition of very low temperature down to 30 mK and ultra high pressure exceeding 200 GPa by assembling compact diamond anvil cell (DAC) on a powerful {sup 3}He/{sup 4}He dilution refrigerator. We have also developed measuring techniques of electrical resistance, magnetization and optical measurement for the sample confined in the sample space of the DAC. Using the newly developed apparatus and techniques, we have searched for superconductivity in various materials under pressure. In this paper, we will shortly review our newly developed experimental apparatus and techniques and discuss a few examples of pressure induced superconductivity which were observed recently.

  12. Effect of pressure on electrical resistance of WSe single crystal

    Indian Academy of Sciences (India)

    Effect of pressure on electrical resistance of WSe. 2 ... Pressure dependence of resistance; transition metal dichalcogenides; WSe2 single crys- ... friction and wear. With lamellar solids such as TMDCs, shearing takes place more easily when loads are high. So lamellar solids are well-suited to extreme pressure lubrication.

  13. 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

  14. 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.)

  15. Mobile Phone Text Messages to Support Treatment Adherence in Adults With High Blood Pressure (SMS-Text Adherence Support [StAR]): A Single-Blind, Randomized Trial.

    Science.gov (United States)

    Bobrow, Kirsten; Farmer, Andrew J; Springer, David; Shanyinde, Milensu; Yu, Ly-Mee; Brennan, Thomas; Rayner, Brian; Namane, Mosedi; Steyn, Krisela; Tarassenko, Lionel; Levitt, Naomi

    2016-02-09

    We assessed the effect of automated treatment adherence support delivered via mobile phone short message system (SMS) text messages on blood pressure. In this pragmatic, single-blind, 3-arm, randomized trial (SMS-Text Adherence Support [StAR]) undertaken in South Africa, patients treated for high blood pressure were randomly allocated in a 1:1:1 ratio to information only, interactive SMS text messaging, or usual care. The primary outcome was change in systolic blood pressure at 12 months from baseline measured with a validated oscillometric device. All trial staff were masked to treatment allocation. Analyses were intention to treat. Between June 26, 2012, and November 23, 2012, 1372 participants were randomized to receive information-only SMS text messages (n=457), interactive SMS text messages (n=458), or usual care (n=457). Primary outcome data were available for 1256 participants (92%). At 12 months, the mean adjusted change in systolic blood pressure compared with usual care was -2.2 mm Hg (95% confidence interval, -4.4 to -0.04) with information-only SMS and -1.6 mm Hg (95% confidence interval, -3.7 to 0.6) with interactive SMS. Odds ratios for the proportion of participants with a blood pressure high blood pressure, we found a small reduction in systolic blood pressure control compared with usual care at 12 months. There was no evidence that an interactive intervention increased this effect. URL: http://www.clinicaltrials.gov. Unique identifier: NCT02019823. South African National Clinical Trials Register, number SANCTR DOH-27-1212-386; Pan Africa Trial Register, number PACTR201411000724141. © 2016 American Heart Association, Inc.

  16. Aspirated High Pressure Compressor

    Science.gov (United States)

    2006-08-01

    suggested by the General Electric Company based on an advanced military engine concept intended for high speed flight. The resultant high flight...section, consisting of the two rotors, each on an computed points. The peak pressure ratio is 3.08 and the peak independent, electric motor-driven...instrumentation along Moto . .. ,oto2 with the test error analysis were given by Onnee [14). SFlywheel 2 BLOWDOWN OPERATION T--’..Exit-t-rottle

  17. Low-temperature single crystal X-ray diffraction and high-pressure Raman studies on [(CH 3) 2NH 2] 2[SbCl 5

    Science.gov (United States)

    Bujak, Maciej; Angel, Ross J.

    2007-11-01

    The structure of bis(dimethylammonium) pentachloroantimonate(III), [(CH 3) 2NH 2] 2[SbCl 5], BDP, was studied at 15 K and ambient pressure by single-crystal X-ray diffraction as well as at ambient temperature and high pressures up to 4.87(5) GPa by Raman spectroscopy. BDP crystallizes in the orthorhombic Pnma space group with a=8.4069(4), b=11.7973(7), c=14.8496(7) Å, and Z=4; R1=0.0381, w R2=0.0764. The structure consists of distorted [SbCl 6] 3- octahedra forming zig-zag [{SbCl 5} n] 2 n- chains that are cross-linked by dimethylammonium [(CH 3) 2NH 2] + cations. The organic and inorganic substructures are bound together by the N-H…Cl hydrogen bonds. The distortions of [SbCl 6] 3- units increase, partly due to the influence of the hydrogen bonds which became stronger, with decreasing temperature. The preliminary room temperature, high-pressure X-ray diffraction experiments suggest that BDP undergoes a first-order phase transition below ca. 0.44(5) GPa that destroys single-crystal samples. The transition is accompanied by changes in the intensities and positions of the Raman lines below 400 cm -1.

  18. Pressure effects on single chain magnets

    Energy Technology Data Exchange (ETDEWEB)

    Mito, M. E-mail: mitoh@elcs.kyutech.ac.jp; Shindo, N.; Tajiri, T.; Deguchi, H.; Takagi, S.; Miyasaka, H.; Yamashita, M.; Clerac, R.; Coulon, C

    2004-05-01

    Pressure effects on a single chain magnet [Mn{sub 2}(saltmen){sub 2}Ni(pao){sub 2}(py){sub 2}](ClO{sub 4}){sub 2} (saltmen{sup 2-}=N,N'-(1,1,2,2-tetramethylethylene)bis(salicylideneiminate), and pao{sup -}=pyridine-2-aldoximate) have been investigated through AC magnetic measurements under pressure (P). The slow relaxation of the magnetization depends on pressure. Both the blocking temperature (T{sub B}) and energy barrier ({delta}) increase by pressurization, and those enhancements saturate at around P=7 kbar.

  19. Diagnosis of High Blood Pressure

    Medline Plus

    Full Text Available ... are two main types of high blood pressure: primary and secondary high blood pressure. Primary High Blood Pressure Primary, ... plan based on whether you were diagnosed with primary or secondary high blood pressure and if there is a ...

  20. High Pressure Scanning Tunneling Microscopy and High PressureX-ray Photoemission Spectroscopy Studies of Adsorbate Structure,Composition and Mobility during Catalytic Reactions on A Model SingleCrystal

    Energy Technology Data Exchange (ETDEWEB)

    Montano, Max O. [Univ. of California, Berkeley, CA (United States)

    2006-01-01

    Our research focuses on taking advantage of the ability of scanning tunneling microscopy (STM) to operate at high-temperatures and high-pressures while still providing real-time atomic resolution images. We also utilize high-pressure x-ray photoelectron spectroscopy (HPXPS) to monitor systems under identical conditions thus giving us chemical information to compare and contrast with the structural and dynamic data provided by STM.

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

    DEFF Research Database (Denmark)

    Periotto, Benedetta

    applications also in the materials science as it can provide useful information about the properties and performance of new materials. Over the past decades, the research in this field has been strongly developed due to the advances in computer capabilities and to the technological improvements of X......-ray instruments. At the same time, the high-pressure experiments have benefited by the strong improvements on the high-pressure devices, in particular the diamond-anvil cell (DAC). The aim of this research project is to assess the quality of the data obtained by means of the single-crystal X-ray diffraction...... started with a comparison between two different DACs, in order to define the capabilities of one of the most common types of pressure device, the ETH-type DAC. Application examples of data quality analysis have been conducted on pyroxenes (NaInSi2O6, orthoenstatite MgSiO3 and LiCrSi2O6), which...

  2. High Pressure Research on Materials

    Indian Academy of Sciences (India)

    ing high pressure are described. Empirical equations of state. (EOS) are illustrated for some standard materials. 1. Introduction. Pressure, like temperature is an important thermodynamic param- eter in our daily life. We use pressure cookers in our kitchen to cook food and use gas cylinders containing LPG at high pressures.

  3. High-Pressure Catalytic Reactions of C6 Hydrocarbons on PlatinumSingle-Crystals and nanoparticles: A Sum Frequency Generation VibrationalSpectroscopic and Kinetic Study

    Energy Technology Data Exchange (ETDEWEB)

    Bratlie, Kaitlin [Univ. of California, Berkeley, CA (United States)

    2007-01-01

    Catalytic reactions of cyclohexene, benzene, n-hexane, 2-methylpentane, 3-methylpentane, and 1-hexene on platinum catalysts were monitored in situ via sum frequency generation (SFG) vibrational spectroscopy and gas chromatography (GC). SFG is a surface specific vibrational spectroscopic tool capable of monitoring submonolayer coverages under reaction conditions without gas-phase interference. SFG was used to identify the surface intermediates present during catalytic processes on Pt(111) and Pt(100) single-crystals and on cubic and cuboctahedra Pt nanoparticles in the Torr pressure regime and at high temperatures (300K-450K). At low pressures (<10-6 Torr), cyclohexene hydrogenated and dehydrogenates to form cyclohexyl (C6H11) and π-allyl C6H9, respectively, on Pt(100). Increasing pressures to 1.5 Torr form cyclohexyl, π-allyl C6H9, and 1,4-cyclohexadiene, illustrating the necessity to investigate catalytic reactions at high-pressures. Simultaneously, GC was used to acquire turnover rates that were correlated to reactive intermediates observed spectroscopically. Benzene hydrogenation on Pt(111) and Pt(100) illustrated structure sensitivity via both vibrational spectroscopy and kinetics. Both cyclohexane and cyclohexene were produced on Pt(111), while only cyclohexane was formed on Pt(100). Additionally, π-allyl c-C6H9 was found only on Pt(100), indicating that cyclohexene rapidly dehydrogenates on the (100) surface. The structure insensitive production of cyclohexane was found to exhibit a compensation effect and was analyzed using the selective energy transfer (SET) model. The SET model suggests that the Pt-H system donates energy to the E2u mode of free benzene, which leads to catalysis. Linear C6 (n-hexane, 2-methylpentane, 3-methylpentane, and 1-hexene) hydrocarbons were also investigated in the presence and absence of excess hydrogen on Pt

  4. High Blood Pressure

    Science.gov (United States)

    ... Immunosuppressant medicines Anxiety, depression and mental health Kidney rejection Lifestyle changes Donate a kidney Being a living ... take a blood pressure medicine. There are many types of blood pressure medicine and you may need to take ...

  5. 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.

  6. Diagnosis of High Blood Pressure

    Medline Plus

    Full Text Available ... of physical activity Drinking too much alcohol Stress Family History A family history of high blood pressure raises the risk ... for high blood pressure and may run in families. Genetic causes of this condition are why family ...

  7. 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 ...

  8. Inactivation of Listeria in Foods Packed in Films Activated with Enterocin AS-48 plus Thymol Singly or in Combination with High-Hydrostatic Pressure Treatment

    Directory of Open Access Journals (Sweden)

    Irene Ortega Blázquez

    2017-11-01

    Full Text Available The aim of the present study was to determine the efficacy of films activated with enterocin AS-48 plus thymol singly, or in combination with high-hydrostatic pressure (HHP on the inactivation of Listeria innocua in sea bream fillets and in fruit puree stored under refrigeration for 10 days. L. innocua proliferated in control fish fillets during storage. The activated film reduced viable Listeria counts in fillets by 1.76 log cycles and prevented growth of survivors until mid-storage. Application of HHP treatment to fillets packed in films without antimicrobials reduced Listeria counts by 1.83 log cycles, but did not prevent the growth of survivors during storage. The combined treatment reduced viable counts by 1.88 log cycles and delayed growth of survivors during the whole storage period. L. innocua survived in puree during storage. The activated film reduced Listeria counts by 1.80 and 2.0 log cycles at days 0 and 3. After that point, Listeria were below the detection limit. No viable Listeria were detected in the purees after application of HHP treatment singly, or in combination with the activated film. Results from the study indicate that the efficacy of activated films against Listeria is markedly influenced by the food type.

  9. High Blood Pressure and Kidney Disease

    Science.gov (United States)

    ... Heart Disease Mineral & Bone Disorder High Blood Pressure & Kidney Disease What is high blood pressure? Blood pressure is ... are the symptoms of high blood pressure and kidney disease? Most people with high blood pressure do not ...

  10. Magnetic and transport properties of PrRu.sub.2./sub.Si.sub.2./sub. single crystal under high pressure

    Czech Academy of Sciences Publication Activity Database

    Vejpravová, J.; Kamarád, Jiří; Prchal, J.; Sechovsky, V.

    2007-01-01

    Roč. 76, suppl. A (2007), s. 49-50 ISSN 0031-9015 Institutional research plan: CEZ:AV0Z10100521 Keywords : pressure effect * magnetic properties * transport properties * single crystal Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 2.212, year: 2007

  11. Laser techniques in high-pressure geophysics

    Science.gov (United States)

    Hemley, R. J.; Bell, P. M.; Mao, H. K.

    1987-01-01

    Laser techniques in conjunction with the diamond-anvil cell can be used to study high-pressure properties of materials important to a wide range of problems in earth and planetary science. Spontaneous Raman scattering of crystalline and amorphous solids at high pressure demonstrates that dramatic changes in structure and bonding occur on compression. High-pressure Brillouin scattering is sensitive to the pressure variations of single-crystal elastic moduli and acoustic velocities. Laser heating techniques with the diamond-anvil cell can be used to study phase transitions, including melting, under deep-earth conditions. Finally, laser-induced ruby fluorescence has been essential for the development of techniques for generating the maximum pressures now possible with the diamond-anvil cell, and currently provides a calibrated in situ measure of pressure well above 100 gigapascals.

  12. 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 ...

  13. 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.

  14. 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)

  15. High pressure storage vessel

    Science.gov (United States)

    Liu, Qiang

    2013-08-27

    Disclosed herein is a composite pressure vessel with a liner having a polar boss and a blind boss a shell is formed around the liner via one or more filament wrappings continuously disposed around at least a substantial portion of the liner assembly combined the liner and filament wrapping have a support profile. To reduce susceptible to rupture a locally disposed filament fiber is added.

  16. Single-Crystal X-Ray Diffraction of Orthoenstatite to 48 GPa: New High-Pressure Phases with 4-, 5-, and 6-Coordinated Silicon

    Science.gov (United States)

    Finkelstein, G. J.; Dera, P. K.; Duffy, T. S.

    2013-12-01

    Orthopyroxene (opx, (Mg,Fe)SiO3) is one of the major phases in Earth's upper mantle, comprising ~20% of the region by volume. At high pressures and temperatures, this phase undergoes several well-characterized phase transitions. Its behavior at low temperature is less well known, but may be important for cold subducting slabs (1, 2). Previous studies (3, 4) reported that MgSiO3 orthoenstatite persists up to ~12 GPa, and a phase transition above this pressure was recently discovered by Zhang et al. (5). This structure, which we call β-opx (designated HPCEN2 in previous studies), is related to one predicted by theory (6), and has P21/c monoclinic symmetry. It retains an opx topology despite its lower symmetry, distinguishing it from a true clinopyroxene. We conducted single-crystal X-ray diffraction experiments in a diamond anvil cell at GSECARS and HPCAT at the APS. Mg0.91Fe0.09SiO3 orthopyroxene was compressed in a neon pressure medium with a gold pressure standard. In addition to the orthopyroxene to β-opx transition, we observe two further phase changes at ~28 GPa and ~38 GPa. The transitions result in volume reductions of ~2.5% and ~3.9%, respectively. The Si layers in both new structures are intermediate between the opx structure and that of the ilmenite-structured akimotoite polymorph. Akimotoite consists of edge-sharing MgO6 and SiO6 octahedra arranged in alternating honeycomb sheets. A theoretical study suggested clinoenstatite could transform directly to akimotoite at low temperatures through a shear-based mechanism (7). Here, we observe that the path toward akimotoite-like Si layers is stepwise. In the new MgSiO3 structures, the initial chains of SiO4 tetrahedra are partially converted to the characteristic 6-coordinated honeycomb layers. This results in some 5-coordinated Si sites in both structures. Due to the increased coordination number, we are calling the new structures α- and β-post-orthopyroxene (α-popx and β-popx). The Mg layers, however, do

  17. High Pressure Research on Materials

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 12; Issue 6. High Pressure Research on Materials - Production and Measurement of High Pressures in the Laboratory. P Ch Sahu N V Chandra Shekar. General Article Volume 12 Issue 6 June 2007 pp 10-23 ...

  18. Managing High Blood Pressure Medications

    Science.gov (United States)

    ... Artery Disease Venous Thromboembolism Aortic Aneurysm More Managing High Blood Pressure Medications Updated:Jan 10,2018 When your doctor ... checkup. This content was last reviewed October 2016. High Blood Pressure • Home • Get the Facts About HBP • Know Your ...

  19. Controlling your high blood pressure

    Science.gov (United States)

    Controlling hypertension ... when you wake up. For people with very high blood pressure, this is when they are most at risk ... 2014 evidence-based guideline for the management of high blood pressure in adults: report from the panel members appointed ...

  20. Common High Blood Pressure Myths

    Science.gov (United States)

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

  1. High Blood Pressure and Women

    Science.gov (United States)

    ... Peripheral Artery Disease Venous Thromboembolism Aortic Aneurysm More High Blood Pressure and Women Updated:Jan 29,2018 Pregnancy and ... Women . This content was last reviewed October 2016. High Blood Pressure • Home • Get the Facts About HBP • Know Your ...

  2. 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...

  3. Diagnosis of High Blood Pressure

    Medline Plus

    Full Text Available ... treatment plans for high blood pressure that include lifelong lifestyle changes and medicines to control high blood ... Managing and coping with stress To help make lifelong lifestyle changes, try making one healthy lifestyle change ...

  4. High Blood Pressure - Multiple Languages

    Science.gov (United States)

    ... High Blood Pressure (Hypertension) - 简体中文 (Chinese, Simplified (Mandarin dialect)) Bilingual PDF Health Information Translations Chinese, Traditional (Cantonese dialect) (繁體中文) Expand Section High ...

  5. 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......, to the electrochemical characterization of high temperature and pressure alkaline electrolysis cells and the use of pseudo-reference electrodes for the separation of each electrode contribution. A future perspective of various electrochemical processes and devices that can be developed with the use of the established...

  6. High pressure phase transformations revisited

    Science.gov (United States)

    Levitas, Valery I.

    2018-04-01

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

  7. High-pressure single-crystal synchrotron X-ray diffraction of kainite (KMg(SO4) Cl 3H2O)

    Science.gov (United States)

    Nazzareni, S.; Comodi, P.; Hanfland, M.

    2018-03-01

    Kainite (KMg(SO4) Cl 3H2O) is a "mixed-salt" sulfate from the group of evaporitic minerals more soluble than Ca-sulfate hydrate and NaCl. The compressibility and structural modifications of monoclinic (sp. gr. C2/m) kainite up to a pressure of 14 GPa were studied by high-pressure single-crystal synchrotron X-ray diffraction. Kainite remains stable over the investigated pressure range and no phase transition was recognised. The bulk modulus is K 0 = 31.6 (1) GPa, with K' fixed to 4, as obtained by fitting the P-volume data with a second-order Birch-Murnaghan EoS (BM2); instead of using a BM3 EoS, we obtained K 0 = 32.2(5) GPa, K' =3.8 (1). The linear moduli calculated for the lattice parameters fitting the data with a BM3 EoS are for a-axis M 0a = 117(4) GPa, Mpa = 11(1), for b-axis M 0b = 113(2) GPa, Mpc = 8.6(5), and c-axis M 0c = 68.2(3) GPa, Mpc = 14(1). Structure refinements showed a strong compression of the K polyhedra and in particular K(1) and K(3) polyhedra have similar polyhedral bulk moduli: K 0K(1) = 20.8(7) GPa, K'=4.8(3); K 0K(2) = 29(1) GPa, K'=8.1(6); K 0K(3) = 26(1) GPa, K'=4.2(4). The most compressible bond distances are K(1)-Cl(2) with a shortening of about 13%, K(1)-Cl(1) with a shortening of about 10%, K(3)-Ow(6) and K(3)-O8(B) both with a shortening of 9%. S-tetrahedra are almost incompressible and Mg-octahedra bulk moduli are K 0Mg(2) = 102(4) GPa, and K 0Mg(4) = 72(1) GPa, K 0Mg(1) = 41(4) GPa K'= 8.9(1.7), and K 0Mg(3) = 65(5) GPa K'= 10(2). The strain tensor analysis indicates that the most compressible direction of the kainite monoclinic structure is oriented 29.7(2)° from the c-axis in the (0 1 0) plane. The shortening of the K(1)-K(2) distance (from 4.219(4) Å at ambient P to 3.521(7) Å at 11.9 GPa) and the different compressibilities of the octahedra/tetrahedra may explain why the stiffer direction of kainite is in the a-c plane approximatively along the direction where K(1)-K(2) and Mg(4)-Mg(3)-Mg(4) polyhedra align. This may

  8. Features from a Single Vector Pressure Stroke

    Directory of Open Access Journals (Sweden)

    Qiang Li

    2017-01-01

    Full Text Available Freehand sketching in a real-time 3D styling system presents a different way to create a 3D model from the traditional CAD system. Strokes are the most common and useful objects in the expression of a stylist’s intention by using the gesture commands and in the construction of geometries. Not only are they sketched freely as drawing on a paper with a pen, but also they can be converted automatically into spline curves and then can be used to form a surface. Therefore, it is necessary to investigate the features of stroke, the extraction and identification of these features, and the applications. Here, the features from a single vector pressure stroke have been discussed in detail according to their applications in an automotive freehand styling system in the early stage of conceptual design. The features have been divided into three parts: the input features, the calculable feature, and the added features. Over a hundred features have been defined and classified with the geometry or performance attributes. The features proposed have been applied in the identification of gesture commands, the expression of art vector stroke by pseudoantialiasing method, and a novel method to generate a spatial curve directly by the pressure of stroke in AutoSketch system.

  9. 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

  10. 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.

  11. Diagnosis of High Blood Pressure

    Medline Plus

    Full Text Available ... system activity , and blood vessel structure and function. Biology and High Blood Pressure Researchers continue to study ... and Your Heart U.S. Department of Health and Human Services' 2008 Physical Activity Guidelines for Americans Maintaining ...

  12. 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.

  13. Diagnosis of High Blood Pressure

    Medline Plus

    Full Text Available ... physical activity Drinking too much alcohol Stress Family History A family history of high blood pressure raises the risk of ... Genetic causes of this condition are why family history is a risk factor for this condition. Screening ...

  14. Medications for High Blood Pressure

    Science.gov (United States)

    ... Consumers Home For Consumers Consumer Updates Medications for High Blood Pressure Share Tweet Linkedin Pin it More sharing options Linkedin Pin it Email Print Hypertension tends to worsen with age and you cannot ...

  15. High blood pressure and diet

    Science.gov (United States)

    Hypertension - diet ... diet is a proven way to help control high blood pressure . These changes can also help you lose weight ... DIET The low-salt Dietary Approaches to Stop Hypertension (DASH) diet is proven to help lower blood ...

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

    Science.gov (United States)

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

  17. Thermal expansion of C60 single crystals under pressure

    International Nuclear Information System (INIS)

    Grube, K.D.

    1995-12-01

    The thermal expansion and compressibility of C 60 single crystals have been investigated by a newly developed capacitive dilatometer. The dilatometer was integrated in a high pressure cell and exposed to a hydrostatic pressure of maximal 0.85 GPa with He or Ar as pressure transmitting medium. The relative length change of the C 60 -samples was measured with a resolution of ΔL/L∼10 -9 . The crystals consist of weakly bonded C 60 -molecules which can rotate nearly free at room temperature. The gradual freezing-in of the rotational motions leads to a first order phase transition at 260 K and a glass transition at 90 K. The pressure dependence of these transitions was determined in a temperature range from 50 K to 325 K up to a pressure of 0.85 GPa. The phase transition at 260 K shows a positive pressure dependence of 174 K/GPa. The glass transition temperature first increases with 75 K/GPa under pressure, then it jumps discontinuously by 10 K at 0.15 GPa followed by a further increase with a slope of 54 K/GPa. The jump in the glass transition temperature at 0.15 GPa can be explained with an orientation-dependent interaction between the C 60 -molecules. (orig.) [de

  18. A method enabling simultaneous pressure and temperature measurement using a single piezoresistive MEMS pressure sensor

    International Nuclear Information System (INIS)

    Frantlović, Miloš; Stanković, Srđan; Jokić, Ivana; Lazić, Žarko; Smiljanić, Milče; Obradov, Marko; Vukelić, Branko; Jakšić, Zoran

    2016-01-01

    In this paper we present a high-performance, simple and low-cost method for simultaneous measurement of pressure and temperature using a single piezoresistive MEMS pressure sensor. The proposed measurement method utilizes the parasitic temperature sensitivity of the sensing element for both pressure measurement correction and temperature measurement. A parametric mathematical model of the sensor was established and its parameters were calculated using the obtained characterization data. Based on the model, a real-time sensor correction for both pressure and temperature measurements was implemented in a target measurement system. The proposed method was verified experimentally on a group of typical industrial-grade piezoresistive sensors. The obtained results indicate that the method enables the pressure measurement performance to exceed that of typical digital industrial pressure transmitters, achieving at the same time the temperature measurement performance comparable to industrial-grade platinum resistance temperature sensors. The presented work is directly applicable in industrial instrumentation, where it can add temperature measurement capability to the existing pressure measurement instruments, requiring little or no additional hardware, and without adverse effects on pressure measurement performance. (paper)

  19. Anxiety: A Cause of High Blood Pressure?

    Science.gov (United States)

    ... cause 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, ...

  20. 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) ...

  1. 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 ...

  2. 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.

  3. 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.

  4. 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.

  5. 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...

  6. 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.

  7. High pressure and high temperature apparatus

    Science.gov (United States)

    Voronov, Oleg A.

    2005-09-13

    A design for high pressure/high temperature apparatus and reaction cell to achieve .about.30 GPa pressure in .about.1 cm volume and .about.100 GPa pressure in .about.1 mm volumes and 20-5000.degree. C. temperatures in a static regime. The device includes profiled anvils (28) action on a reaction cell (14, 16) containing the material (26) to be processed. The reaction cell includes a heater (18) surrounded by insulating layers and screens. Surrounding the anvils are cylindrical inserts and supporting rings (30-48) whose hardness increases towards the reaction cell. These volumes may be increased considerably if applications require it, making use of presses that have larger loading force capability, larger frames and using larger anvils.

  8. 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 information ... Pressure Targets are Different for Very Old Adults High blood pressure (also called hypertension) increases your chance of having ...

  9. Growth and high pressure studies of zirconium sulphoselenide ...

    Indian Academy of Sciences (India)

    tance was monitored in a Bridgman opposed anvil set-up up to 8 GPa pressure to identify the occurrence of any structural transition. These crystals do not possess any structural transitions upto the pressure limit examined. Keywords. Single crystals; chemical vapour transport (CVT) technique; high pressure;. Bridgman anvil ...

  10. [Inflammation in high blood pressure].

    Science.gov (United States)

    Pastelín Hernández, Gustavo; Rosas Peralta, Martín

    2007-01-01

    Inflammatory status is involved in the pathophysiology of several cardiovascular disorders and in the genesis of high blood pressure. In this disease inflammation results from the activity of several hematological cells as well as the presence of chemotactic factors, immunological reactivity and hyperactivity of vasoconstrictor systems as that of the renin-angiotensin. Clinical evaluation of hypertension recommends secreening of several proinflammatory substances in hypertensive patients in order to evaluate their level of cardiovascular risk. Interleukin-6 and C reactive protein have been considered the most usual risk biomarkers. Interleukin 6 is a potent proinflammatory compound which participates in the acute fase of the tissular reaction to lesions associated to immunological, ischemic or oxidative stress. C reactive protein participates during inflammation activating the first component of complement with disorganization of the phospholipidic array of the endothelial sarcolemmal membrane and the consequent endothelial dysfunction related to the genesis of high blood pressure.

  11. Intermolecular Interactions at high pressure

    DEFF Research Database (Denmark)

    Eikeland, Espen Zink

    2016-01-01

    transmitting medium. Through careful structural analysis combined with theoretical calculations, the structures of all the new high-pressure phases identified herein were determined. In the hydroquinone - methanol and hydroquinone - acetonitrile clathrate structures the phase transitions break the host...... illustrates how important it is to quantify all intermolecular interactions in structures. This enables researchers to see a more complete picture and not focus only on a few interactions deemed particularly important....

  12. 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

  13. ACUTE EFFECT OF A SINGLE HIGH-FAT MEAL ON FOREARM BLOOD FLOW, BLOOD PRESSURE AND HEART RATE IN HEALTHY MALE ASIANS AND CAUSASIANS: A PILOT STUDY

    Science.gov (United States)

    Bui, Chumjit; Petrofsky, Jerrold; Berk, Lee; Shavlik, David; Remigio, Wilton; Montgomery, Susanne

    2011-01-01

    Research has shown that ingestion of a single high-fat (HF) meal causes postprandial lipemia and produces a reduced brachial artery blood flow response to vascular occlusion in Caucasians. However, the forearm BF response to occlusion in Caucasian and Asian populations after a single HF meal has not been compared. Eleven healthy male Asians, mean age 26.4 (±4.2) years, height 174.2 (±7.4) cm, and weight 73.8 (±5.7) kg and eight Caucasians, mean age 26.8 (±4.6) years, height 182.9 (±5.9) cm, and weight 82.8 (±4.8) kg were studied. A randomized cross-over study design was used with a HF (50.1 g total fat) or low-fat (LF) (5.1 g total fat) test meal 1 week apart. Forearm blood flow was measured over a 2-minute period following a 4-minute occlusion (FBFO) at 2 and 4 hours following ingestion of a test meal. This study found that FBFO was significantly attenuated in Asians (19.3%; p=0.09) compared to Caucasians after the ingestion of a HF meal. When comparing LF vs HF meals in Asians, the FBFO were 336.9 ml/100 ml tissue/minute and 240.8 ml/100 ml tissue/minute, respectively (p=0.02), whereas in Caucasians, the FBFO were 344.8 ml/100 ml tissue/minute and 287.4 ml/100 ml tissue/minute, respectively. It appears Asians have a more sensitive response to a single HF meal which may be explained, in part, by genotypic variation. These findings suggest that a single HF meal may contribute to the detrimental effects on vascular health in Asian males and raises speculation regarding the cumulative impact of a chronic HF diet in this population. PMID:20578534

  14. High pressure processing of meat

    DEFF Research Database (Denmark)

    Grossi, Alberto; Christensen, Mette; Ertbjerg, Per

    Abstract Background: The research of high pressure (HP) processing of meat based foods needs to address how pressure affects protein interactions, aggregation and/or gelation. The understanding of the gel forming properties of myofibrillar components is fundamental for the development of muscle...... based products (Chapleau et al., 2004;Colmenero, 2002). Object: The aim was to study the rheological properties of pork meat emulsion exposed to HP and the effect of HP on the aggregation state of myofibrillar proteins. To address the role of cathepsin in myofibrillar protein degradation the changes...... in the myofibrillar protein pattern and HP-induced change in activity of cathepsin B and L were investigated. Results: In this study we showed that HP treatment of pork meat emulsion, ranging from 0.1 to 800 MPa, induced protein gel formation as shown by the increased Young’s modulus (Fig.1). Analysis of SDS...

  15. Estimation of turgor pressure through comparison between single plant cell and pressurized shell mechanics

    Science.gov (United States)

    Durand-Smet, P.; Gauquelin, E.; Chastrette, N.; Boudaoud, A.; Asnacios, A.

    2017-10-01

    While plant growth is well known to rely on turgor pressure, it is challenging to quantify the contribution of turgor pressure to plant cell rheology. Here we used a custom-made micro-rheometer to quantify the viscoelastic behavior of isolated plant cells while varying their internal turgor pressure. To get insight into how plant cells adapt their internal pressure to the osmolarity of their medium, we compared the mechanical behavior of single plant cells to that of a simple, passive, pressurized shell: a soccer ball. While both systems exhibited the same qualitative behavior, a simple mechanical model allowed us to quantify turgor pressure regulation at the single cell scale.

  16. 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.)

  17. Pressure spectra from single-snapshot tomographic PIV

    Science.gov (United States)

    Schneiders, Jan F. G.; Avallone, Francesco; Pröbsting, Stefan; Ragni, Daniele; Scarano, Fulvio

    2018-03-01

    The power spectral density and coherence of temporal pressure fluctuations are obtained from low-repetition-rate tomographic PIV measurements. This is achieved by extension of recent single-snapshot pressure evaluation techniques based upon the Taylor's hypothesis (TH) of frozen turbulence and vortex-in-cell (VIC) simulation. Finite time marching of the measured instantaneous velocity fields is performed using TH and VIC. Pressure is calculated from the resulting velocity time series. Because of the theoretical limitations, the finite time marching can be performed until the measured flow structures are convected out of the measurement volume. This provides a lower limit of resolvable frequency range. An upper limit is given by the spatial resolution of the measurements. Finite time-marching approaches are applied to low-repetition-rate tomographic PIV data of the flow past a straight trailing edge at 10 m/s. Reference results of the power spectral density and coherence are obtained from surface pressure transducers. In addition, the results are compared to state-of-the-art experimental data obtained from time-resolved tomographic PIV performed at 10 kHz. The time-resolved approach suffers from low spatial resolution and limited maximum acquisition frequency because of hardware limitations. Additionally, these approaches strongly depend upon the time kernel length chosen for pressure evaluation. On the other hand, the finite time-marching approaches make use of low-repetition-rate tomographic PIV measurements that offer higher spatial resolution. Consequently, increased accuracy of the power spectral density and coherence of pressure fluctuations are obtained in the high-frequency range, in comparison to the time-resolved measurements. The approaches based on TH and VIC are found to perform similarly in the high-frequency range. At lower frequencies, TH is found to underestimate coherence and intensity of the pressure fluctuations in comparison to time-resolved PIV

  18. Effect of pressure on electrical resistance of WSe single crystal

    Indian Academy of Sciences (India)

    Abstract. The results of electrical resistance measurements under pressure on single crystals of. WSe2 are reported. Measurements up to 8.5 GPa are carried out using Bridgman anvil set up and beyond it using diamond anvil cell (DAC) up to a pressure of 27 GPa. There is no clear indication of any phase transition till the ...

  19. Water solubility in pyrope at high pressures

    Science.gov (United States)

    Mookherjee, M.; Karato, S.-

    2006-12-01

    To address how much water is stored within the Earth's mantle, we need to understand the water solubility in the nominally anhydrous minerals. Much is known about olivine and pyroxene. Garnet is another important component, approaching 40% by volume in the transition zone. Only two studies on water solubility in pyrope at high-pressures exist which contradict each other. Lu and Keppler (1997) observed increase in water solubility in a natural pyrope up to 200 ppm wt of water, till 10 GPa. They concluded that the proton is located in the interstitial site. Withers et al. (1998) on the contrary, observed increasing water content in Mg-rich pyrope till 6 GPa, then sudden decrease of water, beyond detection, at 7 GPa. Based on infrared spectra, Withers et al. (1998), concluded hydrogarnet (Si^{4+} replaced by 4H+ to form O4H4) substitution in synthetic magnesium rich pyrope. They argued that at high pressure owing to larger volume, hydrogarnet substitution is unstable and water is expelled out of garnet. In transition zone conditions, however, majorite garnet seems to contain around 600-700 ppm wt of water (Bolfan-Casanova et al. 2000; Katayama et al. 2003). The cause for such discrepancy is not clear and whether garnet could store a significant amount of water at mantle condition is unconstrained. In order to understand the solubility mechanism of water in pyrope at high-pressure, we have conducted high- pressure experiments on naturally occurring single crystals of pyrope garnet (from Arizona, Aines and Rossman, 1984). To ascertain water-saturated conditions, we use olivine single-crystal as an internal standard. Preliminary results indicate that natural pyrope is capable of dissolving water at high-pressures, however, water preferentially enters olivine than in pyrope. We are undertaking systematic study to estimate the solubility of water in pyrope as a function of pressure. This will enable us to develop solubility models to understand the defect mechanisms

  20. Diagnosis of High Blood Pressure

    Medline Plus

    Full Text Available ... the body’s salt balance by retaining sodium and water and excreting potassium. Imbalances in this kidney function ... pressure. Medicines to lower blood pressure include: Diuretics (Water or Fluid Pills): Flush excess sodium from your ...

  1. Electrical Transport Experiments at High Pressure

    Energy Technology Data Exchange (ETDEWEB)

    Weir, S

    2009-02-11

    High-pressure electrical measurements have a long history of use in the study of materials under ultra-high pressures. In recent years, electrical transport experiments have played a key role in the study of many interesting high pressure phenomena including pressure-induced superconductivity, insulator-to-metal transitions, and quantum critical behavior. High-pressure electrical transport experiments also play an important function in geophysics and the study of the Earth's interior. Besides electrical conductivity measurements, electrical transport experiments also encompass techniques for the study of the optoelectronic and thermoelectric properties of materials under high pressures. In addition, electrical transport techniques, i.e., the ability to extend electrically conductive wires from outside instrumentation into the high pressure sample chamber have been utilized to perform other types of experiments as well, such as high-pressure magnetic susceptibility and de Haas-van Alphen Fermi surface experiments. Finally, electrical transport techniques have also been utilized for delivering significant amounts of electrical power to high pressure samples, for the purpose of performing high-pressure and -temperature experiments. Thus, not only do high-pressure electrical transport experiments provide much interesting and valuable data on the physical properties of materials extreme compression, but the underlying high-pressure electrical transport techniques can be used in a number of ways to develop additional diagnostic techniques and to advance high pressure capabilities.

  2. Preeclampsia and High Blood Pressure During Pregnancy

    Science.gov (United States)

    ... AQ FREQUENTLY ASKED QUESTIONS FAQ034 PREGNANCY Preeclampsia and High Blood Pressure During Pregnancy • What is high blood pressure? • What is chronic hypertension? • What is gestational hypertension? • ...

  3. 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 ...

  4. Depth Gauge for Liquids Under High Pressure

    Science.gov (United States)

    Zuckerwar, A. J.; Mazel, D. S.

    1987-01-01

    Piezoelectric element mounted in hole drilled in high-pressure plug. Transducer used to measure depth of liquid when pressure in vessel high. New configuration transmits ultrasonic vibration directly into liquid, enhancing signal strength, accuracy, and range, yet piezoelectric element protected from high-pressure liquid.

  5. 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.

  6. High temperature and pressure electrochemical test station

    Science.gov (United States)

    Chatzichristodoulou, C.; Allebrod, F.; Mogensen, M.

    2013-05-01

    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, to the electrochemical characterization of high temperature and pressure alkaline electrolysis cells and the use of pseudo-reference electrodes for the separation of each electrode contribution. A future perspective of various electrochemical processes and devices that can be developed with the use of the established test station is provided.

  7. Separation of hydrogen isotopes via single column pressure swing adsorption

    International Nuclear Information System (INIS)

    Wong, Y.W.; Hill, F.B.

    1981-01-01

    Separation of hydrogen isotopes based on kinetic isotope effects was studied. The mixture separated was hydrogen containing a trace of tritium as HT and the hydride was vanadium monohydride. The separation was achieved using the single-column pressure swing process. Stage separation factors are larger and product cuts smaller than for a two-column pressure swing process operated in the same monohydride phase

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1997-10-01

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

  9. HIGH BLOOD PRESSURE: DOES THIS CONCERN ME?

    CERN Document Server

    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.

  10. HIGH BLOOD PRESSURE: DOES THIS CONCERN ME?

    CERN Document Server

    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.

  11. 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......), yielding V0 = 495.6(7) Å3 with K0 = 39.9(6) GPa, and V0 = 496.9(7) Å3, with K0 = 36(1) GPa and K′ = 5.1 (4) GPa-1, respectively. The axial moduli were calculated using a Birch-Murnaghan EOS truncated at the second order, fixing K′ equal to 4, for a and b axes and a third-order Birch-Murnaghan EOS for c...... axis. The results were a0 = 11.08(1) and K0 = 56(3) GPa, b0 = 8.20(2) and K0 = 43(3) GPa, and c0 = 5.528(5), K0 = 40(2) GPa, K′ = 1.7(3) GPa-1. The values of the compressibility for a, b, and c axes are ba = 0.0060(3) GPa-1, bb = 0.0078(5) GPa-1, bc = 0.0083(4) GPa-1 with an anisotropic ratio of ba...

  12. Diagnosis of High Blood Pressure

    Medline Plus

    Full Text Available ... to Aim for a Healthy Weight . Limiting Alcohol Intake Limit alcohol intake. Too much alcohol will raise your blood pressure ... physically active. Maintain a healthy weight. Limit alcohol intake. Other lifestyle changes can improve your overall health, ...

  13. High-pressure synthesis and single-crystal structure elucidation of the indium oxide-borate In{sub 4}O{sub 2}B{sub 2}O{sub 7}

    Energy Technology Data Exchange (ETDEWEB)

    Ortner, Teresa S.; Vitzthum, Daniela; Heymann, Gunter; Huppertz, Hubert [Department of General, Inorganic and Theoretical Chemistry, Centre of Chemistry and Biomedicine (CCB), Leopold-Franzens-University Innsbruck (Austria)

    2017-12-29

    The indium oxide-borate In{sub 4}O{sub 2}B{sub 2}O{sub 7} was synthesized under high-pressure/high-temperature conditions at 12.5 GPa/1420 K using a Walker-type multianvil apparatus. Single-crystal X-ray structure elucidation showed edge-sharing OIn{sub 4} tetrahedra and B{sub 2}O{sub 7} units building up the oxide-borate. It crystallizes with Z = 8 in the monoclinic space group P2{sub 1}/n (no. 14) with a = 1016.54(3), b = 964.55(3), c = 1382.66(4) pm, and β = 109.7(1) . The compound was also characterized by powder X-ray diffraction and vibrational spectroscopy. (copyright 2017 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  14. High-pressure study on some superconductors

    CERN Document Server

    Li, K Q; Yao, Y S; Che, G C; Zhao, Z X

    2002-01-01

    High-pressure study has played an important role in the investigation of conventional superconductors. Since the discovery of cuprate superconductors, high-pressure study has become even more important, especially as regards high-pressure synthesis and the effect of pressure. In this report, the new materials Ca-doped Pr-123, (Fe, Cu)-1212, and MgB sub 2 - a very new and interesting system synthesized under high pressure with good quality - will be discussed. Chemical inner pressure has been thought to explain the high T sub c of Ca-doped Pr-123. As another possibility, the replacement of the physical pressure effect by a chemical effect will be discussed.

  15. High pressure growth and electron transport properties of superconducting SmFeAsO1−xHx single crystals

    Directory of Open Access Journals (Sweden)

    Soshi Iimura

    2017-09-01

    Full Text Available We report the single crystal growth and characterization of the highest Tc iron-based superconductor SmFeAsO1−xHx. Some sub-millimeter-sized crystals were grown using the mixture flux of Na3As + 3NaH + As at 3.0 GPa and 1473 K. The chemical composition analyses confirmed 10% substitution of hydrogen for the oxygen site (x = 0.10, however, the structural analyses suggested that the obtained crystal forms a multi-domain structure. By using the FIB technique we fabricated the single domain SmFeAsO0.9H0.10 crystal with the Tc of 42 K, and revealed the metallic conduction in in-plane (ρab, while semiconducting in the out-of-plane (ρc. From the in-plane Hall coefficient measurements, we confirmed that the dominant carrier of SmFeAsO0.9H0.10 crystal is an electron, and the hydride ion occupied at the site of the oxygen ion effectively supplies a carrier electron per iron following the equation: O2− → H− + e−.

  16. 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

  17. High pressure study of high-temperature superconductors

    Energy Technology Data Exchange (ETDEWEB)

    Souliou, Sofia-Michaela

    2014-09-29

    Imm2). The structural transition is clearly reflected in the high pressure Raman data through the appearance of several new modes, allowing us to map in detail the (P,T) phase diagram and determine the transition line between the two phases. In the new phase, the renormalization of the buckling mode is completely suppressed, while no anomalies are observed in any of the other Raman active phonons. According to ab initio calculations, the coupling of the buckling mode to the electronic system is not significantly affected by the structural phase transition. The absence of phonon renormalizations in the presence of sizable electron-phonon coupling, indicate that, in contrast to earlier transport studies, YBa{sub 2}Cu{sub 4}O{sub 8} is not superconducting anymore under hydrostatic pressures higher than 10 GPa. Finally we proceeded with the investigation of the high pressure structural and vibrational properties of SmFeAsO, a member of the ''1111'' family (space group P4/nmm) of the Fe-based superconductors, in which superconductivity is commonly induced either by substituting F/H for O or by applying high pressures on the parent magnetic compound. The magnetic transition of the undoped compound is accompanied with a tetragonal-to-orthorhombic structural distortion, both of which are commonly suppressed upon the emergence of superconductivity. In the SmFeAsO{sub x}F{sub 1-x} system while the magnetic transition is totally suppressed already at low doping levels, structural studies have reported either the gradual suppression of the orthorhombic distortion or its retention over a wide regime of the superconducting phase. We addressed this controversy using high pressure as an alternative tuning parameter to suppress the magneto-structural transition and induce superconductivity in the parent compound. Our high pressure, low temperature X-ray diffraction measurements on single crystals of SmFeAsO have revealed that the tetragonal

  18. Critical cerebral perfusion pressure at high intracranial pressure measured by induced cerebrovascular and intracranial pressure reactivity.

    Science.gov (United States)

    Bragin, Denis E; Statom, Gloria L; Yonas, Howard; Dai, Xingping; Nemoto, Edwin M

    2014-12-01

    The lower limit of cerebral blood flow autoregulation is the critical cerebral perfusion pressure at which cerebral blood flow begins to fall. It is important that cerebral perfusion pressure be maintained above this level to ensure adequate cerebral blood flow, especially in patients with high intracranial pressure. However, the critical cerebral perfusion pressure of 50 mm Hg, obtained by decreasing mean arterial pressure, differs from the value of 30 mm Hg, obtained by increasing intracranial pressure, which we previously showed was due to microvascular shunt flow maintenance of a falsely high cerebral blood flow. The present study shows that the critical cerebral perfusion pressure, measured by increasing intracranial pressure to decrease cerebral perfusion pressure, is inaccurate but accurately determined by dopamine-induced dynamic intracranial pressure reactivity and cerebrovascular reactivity. Cerebral perfusion pressure was decreased either by increasing intracranial pressure or decreasing mean arterial pressure and the critical cerebral perfusion pressure by both methods compared. Cortical Doppler flux, intracranial pressure, and mean arterial pressure were monitored throughout the study. At each cerebral perfusion pressure, we measured microvascular RBC flow velocity, blood-brain barrier integrity (transcapillary dye extravasation), and tissue oxygenation (reduced nicotinamide adenine dinucleotide) in the cerebral cortex of rats using in vivo two-photon laser scanning microscopy. University laboratory. Male Sprague-Dawley rats. At each cerebral perfusion pressure, dopamine-induced arterial pressure transients (~10 mm Hg, ~45 s duration) were used to measure induced intracranial pressure reactivity (Δ intracranial pressure/Δ mean arterial pressure) and induced cerebrovascular reactivity (Δ cerebral blood flow/Δ mean arterial pressure). At a normal cerebral perfusion pressure of 70 mm Hg, 10 mm Hg mean arterial pressure pulses had no effect on

  19. Single-crystal X-ray diffraction study of SrGeO3 high-pressure perovskite phase at 100 K

    Science.gov (United States)

    Nakatsuka, Akihiko; Arima, Hiroshi; Ohtaka, Osamu; Fujiwara, Keiko; Yoshiasa, Akira

    2017-10-01

    Single-crystal X-ray diffraction study of SrGeO3 perovskite (cubic; space group Pmɜ¯m) synthesized at 6 GPa and 1223 K was conducted at a low temperature of 100 K. The residual electron density revealed the presence of the bonding electron at the center of the Ge-O bond, in accordance with our previous conclusion that the Ge-O bond is strongly covalent. From comparison with our previous structure-refinement result at 296 K, the mean square displacement (MSD) of the O atom in the direction of the Ge-O bond is suggested to exhibit no significant temperature dependence, in contrast to that in the direction perpendicular to the bond. Thus, the strong covalency of the Ge-O bond can have a large influence on the temperature dependence of thermal vibration of the O atom.

  20. High Precision Pressure Measurement with a Funnel

    Science.gov (United States)

    Lopez-Arias, T.; Gratton, L. M.; Oss, S.

    2008-01-01

    A simple experimental device for high precision differential pressure measurements is presented. Its working mechanism recalls that of a hydraulic press, where pressure is supplied by insufflating air under a funnel. As an application, we measure air pressure inside a soap bubble. The soap bubble is inflated and connected to a funnel which is…

  1. High-pressure cell for neutron scattering

    International Nuclear Information System (INIS)

    Onodera, Akifumi; Nakai, Yutaka; Kunitomi, Nobuhiko

    1987-01-01

    We have developed a high-pressure cell for neutron scattering. The cell uses a barrel-shaped support cylinder made of sintered ceramics. Samples 6 mm in diameter and 10 mm long can be accommodated. The cell is suitable for use at low and high temperatures, after a pressure generated at room temperature is locked. The change of pressure on cooling to cryogenic temperatures is estimated by measuring the lattice parameter of NaCl. Besides the pressure locking technique, continuous pressurization can be achieved at room temperature by using a built-in mini-press while the cell is mounted on a goniometer of neutron spectrometer. (author)

  2. Recent high pressure photoluminescence studies

    Energy Technology Data Exchange (ETDEWEB)

    Drickamer, H.G.; Lang, J.M.; Dreger, Z.A. (Department of Chemical Engineering, University of Illinois, 1209 W. California Street, Urbana, Illinois 61801 (United States))

    1994-07-10

    In this paper we discuss two studies involving the effect of pressure on luminescence properties of organic molecules in polymeric media. (1) The efficiency of energy transfer from Coumarine 138 to Rhodamine B in polyacrylic acid (PAA) is measured by both steady state and time dependent methods. The Forster efficiency'' obtained by these two methods is consistent and shows the same pressure dependence as efficiencies derived from relative peak intensities. The non-monotonic pressure dependence of the efficiency is accounted for in terms of the properties of the molecules and the media. (2) The effect of pressure on the luminescent efficiency of molecules with two or more possible excited state geometries has been measured. The efficiency is described in terms of the non-radiative dissipation of energy from a planar excited state and the rates of crossing to and from the possible twisted states as well as non-radiative decay from these states. The processes involved in these two studies are pertinent to a number of technologically and biologically important processes. [copyright]American Institute of Physics

  3. Vega Subsea Development - a high pressure et high temperature challenge

    Energy Technology Data Exchange (ETDEWEB)

    Erlandsen, Jostein

    2010-07-01

    The Vega subsea field, tied back to the Gjoea platform with a 51 kilometre single pipeline is one of the most challenging technology projects undertaken by Statoil. It is the combination of extremes rather than one record breaking achievement that set the Vega development apart. Production temperatures from -30 C to +135 C and flowing wellhead pressure up to 475 bars combined with high wax appearance temperature and low start-up temperatures expose Vega to both wax deposition and hydrates. New subsea metering systems have been developed due to coming led production from two licenses and two independent subsea MEG injection systems implemented. The paper will focus on the qualification process of barrier elements and the potential challenges related to qualification of complex production and safety critical systems such as the subsea production control system and the subsea instrumented pipeline pressure protection system (SIPPS). (Author)

  4. Finite single wall capped carbon nanotubes under hydrostatic pressure

    International Nuclear Information System (INIS)

    Baltazar, S E; Romero, A H; RodrIguez-Lopez, J L; Martonak, R

    2006-01-01

    We report a classical molecular dynamics isothermal-isobaric ensemble (NPT) implementation for the simulation of pressure effects on finite systems. The method is based on calculating the enclosed surface area by means of the Delauney triangulation method, which results in a fairly accurate description of the surface and the system volume. The external pressure is applied to the system by external forces acting on the triangulated surface covering the nanostructure. Pressure is exerted perpendicularly to every one of the Delauney triangles, by equally distributing the force to every corner of a triangle. We applied the method to finite single wall capped carbon nanotubes (SWCNTs) with different chiralities and different tube lengths ranging from 4 nm up to 30 nm. Pressure effects are studied as a function of the radii and the nanotube length, as well as as a function of temperature. Our results are in very good agreement when compared with both experimental and other theoretical results

  5. Accessing Mefenamic Acid Form II through High-Pressure Recrystallisation

    Directory of Open Access Journals (Sweden)

    Nasir Abbas

    2017-05-01

    Full Text Available High-pressure crystallisation has been successfully used as an alternative technique to prepare Form II of a non-steroidal anti-inflammatory drug, mefenamic acid (MA. A single crystal of Form II, denoted as high-pressure Form II, was grown at 0.3 GPa from an ethanolic solution by using a diamond anvil cell. A comparison of the crystal structures shows that the efficient packing of molecules in Form II was enabled by the structural flexibility of MA molecules. Compression studies performed on a single crystal of Form I resulted in a 14% decrease of unit cell volume up to 2.5 GPa. No phase transition was observed up to this pressure. A reconstructive phase transition is required to induce conformational changes in the structure, which was confirmed by the results of crystallisation at high pressure.

  6. Conventional high pressure techniques fro neutron diffraction

    International Nuclear Information System (INIS)

    Mizuki, Jun-ichiro; Endoh, Yasuo

    1981-01-01

    Conventional high pressure techniques using a clamped type pressure cell have been adapted for studies by neutron diffraction. Careful calibration of the pressure sensing apparatus and an appropriate choice of pressure transmitting medium enable accurate neutron diffraction measurements to be made at reduced temperature as low as 4 K. In the present studies we have demonstrated that using the clamped type microbomb neutron diffraction measurements can be easily made under the pressure up to 5 kbar within the temperature range 4 K - 350 K. (author)

  7. High pressure studies of molecular lumenescence

    Energy Technology Data Exchange (ETDEWEB)

    Drickamer, H.G.

    1982-01-01

    The studies of high pressure molecular luminescence reviewed, along with results for inorganic systems discussed elsewhere, provide evidence about the versatility and power of high pressure as a tool for characterizing electronic states, testing theories concerning electronic phenomena, and generally obtaining a better understanding of electronic behavior in condensed systems. 16 figures.

  8. Coal swelling and thermoplasticity under high pressure

    Energy Technology Data Exchange (ETDEWEB)

    Ndaji, F.E.; Butterfield, I.M.; Thomas, K.M. (Newcastle upon Tyne University, Newcastle upon Tyne (United Kingdom). Northern Carbon Research Labs., Dept. of Chemistry)

    1992-01-01

    The literature on the following topics is reviewed: swelling and agglomeration of coal; measurements of swelling index and dilatometric and plastometric properties at high pressures; and the effects of oxidation, tar addition and minerals on high-pressure thermoplastic properties. 34 refs., 6 figs.

  9. Managing Stress to Control High Blood Pressure

    Science.gov (United States)

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

  10. 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

  11. High pressure gas laser technology for atmospheric remote sensing

    Science.gov (United States)

    Javan, A.

    1980-01-01

    The development of a fixed frequency chirp-free and highly stable intense pulsed laser made for Doppler wind velocity measurements with accurate ranging is described. Energy extraction from a high pressure CO2 laser at a tunable single mode frequency is also examined.

  12. DASH diet to lower high blood pressure

    Science.gov (United States)

    ... ency/patientinstructions/000770.htm DASH diet to lower high blood pressure To use the sharing features on this page, ... JavaScript. DASH stands for Dietary Approaches to Stop Hypertension. The DASH diet can help lower high blood ...

  13. 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...

  14. 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

  15. Atmospheric pressure nitrogen laser made by single block ceramics

    Energy Technology Data Exchange (ETDEWEB)

    Zhang Yuchuan; Wang Huaiming; Rao Deyi; Yan Zhicheng; Ge Qian; Li Yue; Zhang Yilu; Xie Yan

    1986-02-01

    This paper reports the experimental research for atmospheric pressure nitrogen laser of short tube design, with a single block ceramics as dielectric. With the laser discharge electrode 5.8 cm in length, we got pulse energy of 13 ..mu..J at 100 Hz, with a maximum average power of 1.3 mW, a pulse width of 0.8 ns, and a beam divergence of 1.3 x 3 mrad.

  16. Structure and stability of hydrous minerals at high pressure

    Science.gov (United States)

    Duffy, T. S.; Fei, Y.; Meade, C.; Hemley, R. J.; Mao, H. K.

    1994-01-01

    The presence of even small amounts of hydrogen in the Earth's deep interior may have profound effects on mantle melting, rheology, and electrical conductivity. The recent discovery of a large class of high-pressure H-bearing silicates further underscores the potentially important role for hydrous minerals in the Earth's mantle. Hydrogen may also be a significant component of the Earth's core, as has been recently documented by studies of iron hydride at high pressure. In this study, we explore the role of H in crystal structures at high pressure through detailed Raman spectroscopic and x ray diffraction studies of hydrous minerals compressed in diamond anvil cells. Brucite, Mg(OH)2, has a simple structure and serves as an analogue for the more complex hydrous silicates. Over the past five years, this material has been studied at high pressure using shock-compression, powder x ray diffraction, infrared spectroscopy, Raman spectroscopy, and neutron diffraction. In addition, we have recently carried out single-crystal synchrotron x-ray diffraction on Mg(OH)2 and Raman spectroscopy on Mg(OD)2 at elevated pressure. From all these studies, an interesting picture of the crystal chemical behavior of this material at high pressure is beginning to emerge. Some of the primary conclusions are as follows: First, hydrogen bonding is enhanced by the application of pressure. Second, layered minerals which are elastically anisotropic at low pressure may not be so at high pressure. Furthermore, the brucite data place constraints on the effect of hydrogen on seismic velocities and density at very high pressure. Third, the stability of hydrous minerals may be enhanced at high P by subtle structural rearrangements that are difficult to detect using traditional probes and require detailed spectroscopic analyses. Finally, brucite appears to be unique in that it undergoes pressure-induced disordering that is confined solely to the H-containing layers of the structure.

  17. Diagnosis of High Blood Pressure

    Medline Plus

    Full Text Available ... management techniques include: Being physically active Listening to music or focusing on something calm or peaceful Performing ... multidisciplinary researchers on June 10, 2016, to share current scientific k... View all events on High Blood ...

  18. 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.

  19. A High Pressure Apparatus for Neutron Diffraction

    OpenAIRE

    Kazuo, Kamigaki; Hajime, Yoshida; Masayoshi, Ohashi; Takejiro, Kaneko; Kozaburo, Sato; The Research Institute for Iron, Steel and Other Metals; The Research Institute for Iron, Steel and Other Metals; The Research Institute for Iron, Steel and Other Metals; The Research Institute for Iron, Steel and Other Metals; Department of Physics, Faculty of Science, Hirosaki University

    1980-01-01

    A high pressure apparatus was developed for thermal neutron diffraction of time-of-flight method. The high pressure vessel was a piston-cylinder type, and Ti-Zr alloy was used as a material of the cylinder. The coherent scattering of neutron is suppressed in Ti-53wt% Zr alloy. The diffraction spectrum is formed of peaks from the specimen and a background, which corresponds to the energy distribution of the incident neutron. High pressure measurements were made in RbBr on the transformation be...

  20. 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

  1. 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...

  2. Swelling pressure of highly compacted bentonite

    International Nuclear Information System (INIS)

    Pusch, R.

    1980-08-01

    Highly compacted, dense Na bentonite is used to isolate metal canisters with highly radioactivity waste products from the surrounding rock. The main object was to investigate the relationship between the swelling pressure and bulk density of bentonite with special reference to the influence of ion exchange and temperature. A new type of oedometer for swelling pressure tests was developed. It was found that there seemed to be unique relationship between the bulk density and the sweeling pressure, and that a temperature increase to 70deg C reduced the pressure to approximately 50% of the value at 20degC. It was observed that the pore water chemistry was hardle a determinant of the swelling pressure in the bulk density above 2 ton per m 3 . (G.B.)

  3. 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...... 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...... 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...

  4. Ion Based High-Temperature Pressure Sensor

    National Research Council Canada - National Science Library

    Zdenek, Jeffrey S; Anthenien, Ralph A

    2004-01-01

    .... The environment encountered in such engines necessitates high temperature and durable (vibration resistant) devices. Traditional pressure sensors can be used, however thermal insulating materials must be used to protect the diaphragm...

  5. Design of high pressure waterjet nozzles

    Science.gov (United States)

    Mazzoleni, Andre P.

    1994-10-01

    The Hydroblast Research Cell at Marshall Space Flight Center is used to investigate the use of high pressure waterjets to strip paint, grease, adhesive and thermal spray coatings from various substrates. Current methods of cleaning often use ozone depleting chemicals (ODC) such as chlorinated solvents. High pressure waterjet cleaning has proven to be a viable alternative to the use of solvents. A popular method of waterjet cleaning involves the use of a rotating, multijet, high pressure water nozzle which is robotically controlled. This method enables rapid cleaning of a large area, but problems such as incomplete coverage and damage to the substrate from the waterjet have been observed. This report summarizes research consisting of identifying and investigating the basic properties of rotating, multijet, high pressure water nozzles, and how particular designs and modes of operation affect such things as stripping rate, standoff distance and completeness of coverage. The study involved computer simulations, an extensive literature review, and experimental studies of different nozzle designs.

  6. High-pressure polymorphs of anatase TiO2

    DEFF Research Database (Denmark)

    Arlt, T.; Bermejo, M.; Blanco, M. A.

    2000-01-01

    The equation of state of anatase TiO2 has been determined experimentally-using polycrystalline as well as single-crystal material-and compared with theoretical calculations using the ab initio perturbed ion model. The results are highly consistent, the zero-pressure bulk modulus being 179(2) GPa ...

  7. CARS Diagnostics of High Pressure Combustion.

    Science.gov (United States)

    1982-11-01

    e) 8. CONTRACT OR GRANT NUMBER(e) J. H. Stufflebeam t JDAAG29- 79-C-0008J %A,, Shirley R,,. Hall 9. PERFORMING ORGANIZATION NAME AND ADDRESS 10...also the work in N2 at elevated tem- perature up to 30 atmospheres. John H. Stufflebeam continued the high pressure CARS work under the contract...Spectroscopy, Bordeaux, France, September 1982. 12. J. H. Stufflebeam , J. F. Verdieck, and R. J. Hall: CARS Diagnostics of High Pressure and

  8. 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...

  9. High pressure structural studies of conjugated molecules

    DEFF Research Database (Denmark)

    Knaapila, Matti; Torkkeli, Mika; Scherf, Ullrich

    2018-01-01

    This chapter highlights high pressure GPa level structural studies of conjugated polymers and their analogues: conjugated oligomers and molecules, and rigid rod polymers. Attention is placed on our recent studies of polyfluorenes.......This chapter highlights high pressure GPa level structural studies of conjugated polymers and their analogues: conjugated oligomers and molecules, and rigid rod polymers. Attention is placed on our recent studies of polyfluorenes....

  10. 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.

  11. Experiments on aerosol removal by high-pressure water spray

    International Nuclear Information System (INIS)

    Corno, Ada del; Morandi, Sonia; Parozzi, Flavio; Araneo, Lucio; Casella, Francesco

    2017-01-01

    Highlights: • Experimental research to measure the efficiency of high-pressure sprays in capturing aerosols if applied to a filtered containment venting system in case of severe accident. • Cloud of monodispersed SiO 2 particles with sizes 0.5 or 1.0 μm and initial concentration in the range 2–90 mg/m 3 . • Carried out in a chamber 0.5 × 1.0 m and 1.5 m high, with transparent walls equipped with a high pressure water spray with single nozzle. • Respect to low-pressure sprays, removal efficiency turned out significant: the half-life for 1 μm particles with a removal high-pressure spray system is orders of magnitude shorter than that with a low-pressure sprays system. - Abstract: An experimental research was managed in the framework of the PASSAM European Project to measure the efficiency of high-pressure sprays in capturing aerosols when applied to a filtered containment venting system in case of severe accident. The campaign was carried out in a purposely built facility composed by a scrubbing chamber 0.5 × 1.0 m and 1.5 m high, with transparent walls to permit the complete view of the aerosol removal process, where the aerosol was injected to form a cloud of specific particle concentration. The chamber was equipped with a high pressure water spray system with a single nozzle placed on its top. The test matrix consisted in the combination of water pressure injections, in the range 50–130 bar, on a cloud of monodispersed SiO 2 particles with sizes 0.5 or 1.0 μm and initial concentration ranging between 2 and 99 mg/m 3 . The spray was kept running for 2 min and the efficiency of the removal was evaluated, along the test time, using an optical particle sizer. With respect to low-pressure sprays, the removal efficiency turned out much more significant: the half-life for 1 μm particles with a removal high-pressure spray system is orders of magnitude shorter than that with a low-pressure spray system. The highest removal rate was detected with 1

  12. A high pressure apparatus for neutron diffraction

    International Nuclear Information System (INIS)

    Kamigaki, Kazuo; Yoshida, Hajime; Ohashi, Masayoshi; Kaneko, Takejiro; Sato, Kozaburo.

    1980-01-01

    A high pressure apparatus was developed for thermal neutron diffraction of time-of-flight method. The high pressure vessel was a piston-cylinder type, and Ti-Zr alloy was used as a material of the cylinder. The coherent scattering of neutron is suppressed in Ti-53wt% Zr alloy. The diffraction spectrum is formed of peaks from the specimen and a background, which corresponds to the energy distribution of the incident neutron. High pressure measurements were made in RbBr on the transformation between NaCl-type structure and CsCl-type to a pressure about 20 kb, and a good agreement was confirmed with former experiments. (author)

  13. 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...

  14. High precision pressure measurement with a funnel

    International Nuclear Information System (INIS)

    Lopez-Arias, T; Gratton, L M; Oss, S

    2008-01-01

    A simple experimental device for high precision differential pressure measurements is presented. Its working mechanism recalls that of a hydraulic press, where pressure is supplied by insufflating air under a funnel. As an application, we measure air pressure inside a soap bubble. The soap bubble is inflated and connected to a funnel which is placed, upside down, in a container filled with distilled water, placed on a scale. Our method provides a theoretical precision for the pressure measurement of the order of 0.01 Pa. Beyond this, the advantage of this method relies on the simplicity of the materials used and on the opportunity to discuss, at an undergraduate level, basic concepts regarding all those phenomena in which low or very low differential pressures are relevant

  15. Solids, liquids, and gases under high pressure

    Science.gov (United States)

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

    2018-01-01

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

  16. Pressure sensor for high-temperature liquids

    International Nuclear Information System (INIS)

    1980-01-01

    A pressure sensor for use with liquid metals (eg Na and K) over the pressure range 0 - 2MPa and temperature range 644 - 922'K is described. A soft diaphragm is exposed on one side to the fluid (liquid metal) and on the other to a first source of gas at a first gas pressure. A stiff diaphragm is exposed on one side to the first gas source and on the other side by a second source of gas at a second pressure. The stiff diaphragm is in pushing engagement with the soft diaphragm such that movement is transmitted to the stiff diaphragm when the pressure in the fluid exceeds the first and second gas pressures. The displacement of the stiff diaphragm is measured and is a function of the fluid pressure. Details of the measuring means are given. A version for insertion in a wall of a container to measure pressure in high temperature liquid metals in the container is described. It comprises an annular bellows connected by an outer peripheral edge to the wall of the container, a stiff disc connected at an outer edge to an inner edge of the bellows and forming therewith a soft diaphragm. The operation is similar to that previously described. Full details are given. (U.K.)

  17. 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

  18. Neutron diffraction under high pressure and high temperature

    International Nuclear Information System (INIS)

    Komatsu, Kazuki

    2010-01-01

    Neutron diffraction study under high pressure and high temperature is reviewed from the technical point of view. Particularly, cell assembly for the high-PT neutron diffraction using a Paris-Edinburgh cell with the temperature calibration by neutron resonance spectroscopy is introduced. Notes on the errors relevant to high pressure and high temperature experiments in both monochromatic angle dispersive and time-of-flight methods are also discussed. (author)

  19. observed by high pressure NMR and NQR

    Indian Academy of Sciences (India)

    Department of Material Science, Himeji Institute of Technology, Kamigori,. 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 ...

  20. High-pressure polymorphism of acetylsalicylic acid (aspirin): Raman spectroscopy

    Science.gov (United States)

    Crowell, Ethan L.; Dreger, Zbigniew A.; Gupta, Yogendra M.

    2015-02-01

    Micro-Raman spectroscopy was used to elucidate the high-pressure polymorphic behavior of acetylsalicylic acid (ASA), an important pharmaceutical compound known as aspirin. Using a diamond anvil cell (DAC), single crystals of the two polymorphic phases of aspirin existing at ambient conditions (ASA-I and ASA-II) were compressed to 10 GPa. We found that ASA-I does not transform to ASA-II, but instead transforms to a new phase (ASA-III) above ∼2 GPa. It is demonstrated that this transformation primarily introduces structural changes in the bonding and arrangement of the acetyl groups and is reversible upon the release of pressure. In contrast, a less dense ASA-II shows no transition in the pressure range studied, though it appears to exhibit a disordered structure above 7 GPa. Our results suggest that ASA-III is the most stable polymorph of aspirin at high pressures.

  1. 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.

  2. 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

  3. Hypertensive patients' knowledge of high blood pressure.

    Science.gov (United States)

    Kjellgren, K I; Svensson, S; Ahlner, J; Säljö, R

    1997-12-01

    To investigate hypertensive patients' understanding of the circulatory system, in particular high blood pressure. Semi-structured audio-taped interviews of patients immediately after a regular follow-up appointment with their physician. A primary health care centre and a specialist clinic (hypertension unit) in southern Sweden. 33 hypertensive patients, consecutively selected. Focus was set on the exploration of patients' understanding/knowledge. In spite of a long history of hypertensive care, on average ten years, patients had a less than satisfactory understanding of their condition. Most patients knew their blood pressure values, but very few were able to give an account of what high blood pressure implies in functional terms. Knowledge of high blood pressure seems mainly to be derived from sources other than the health care system, in particular from the mass media. Knowledge of the risks associated with hypertension was quite good, as was the insight into how these risks could be managed. An assessment of patient knowledge of high blood pressure ought to be a starting point for educational strategies that aim to deepen patients' understanding of their state of health.

  4. 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

  5. Curved and conformal high-pressure vessel

    Science.gov (United States)

    Croteau, Paul F.; Kuczek, Andrzej E.; Zhao, Wenping

    2016-10-25

    A high-pressure vessel is provided. The high-pressure vessel may comprise a first chamber defined at least partially by a first wall, and a second chamber defined at least partially by the first wall. The first chamber and the second chamber may form a curved contour of the high-pressure vessel. A modular tank assembly is also provided, and may comprise a first mid tube having a convex geometry. The first mid tube may be defined by a first inner wall, a curved wall extending from the first inner wall, and a second inner wall extending from the curved wall. The first inner wall may be disposed at an angle relative to the second inner wall. The first mid tube may further be defined by a short curved wall opposite the curved wall and extending from the second inner wall to the first inner wall.

  6. 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.

  7. 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.

  8. 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

  9. High pressure BF3 proportional counter

    International Nuclear Information System (INIS)

    Mihara, Masaru; Gotoh, Eiichiro; Kodama, Masahiro

    1978-01-01

    Plateau and pulse characteristics of high pressure BF 3 proportional counter were investigated in terms of counter geometry and gas pressure, in order to develop a small-sized and high-sensitive one. Description is given of the construction of improved gas filling equipment with filling procedure. A tentative brass counter, 67 mm in cathode diameter, 40 micron in anode diameter, filled to 1.2 kg/cm 2 revealed characteristics of 150 volts plateau range, the slope of which being 3% per 100 volts at the operation voltage of around 3.3 kV, and 103% full width at half-maximum in the pulse height distribution. (auth.)

  10. High temperature and pressure alkaline electrolysis

    Energy Technology Data Exchange (ETDEWEB)

    Ganley, Jason C. [Department of Chemical Engineering, Howard University, 2013 Lewis K. Downing Hall, 2300 6th Street NW, Washington, DC 20059 (United States)

    2009-05-15

    This paper describes experimental work involving the direct-current electrolysis of highly concentrated potassium hydroxide solutions at high temperatures (up to 400 C) and under various pressures. A high-temperature alkaline electrolysis cell resistant to chemical attack from the highly corrosive electrolyte solution and capable of high-pressure operation was designed and tested. The cell was constructed with a Monel {sup registered} alloy housing and cathode, while various anode materials were compared. The anode materials tested included nickel, Monel alloy, lithiated nickel, and cobalt-plated nickel. The advantages of operating an alkaline electrolysis cell at high temperatures include increasing the ionic conductivity of the electrolyte and enhancing the rates of electrochemical reactions at the electrode surfaces. Cell operation with increasing steam partial pressure over the solution is also shown to enhance cell performance. The prudent selection of anode material also impacts the required terminal potential for a given current density, and consequently the cell's electric power efficiency. The best cell performance was achieved using a cobalt-plated nickel anode at a temperature of 400 C and a steam partial pressure of 8.7 MPa. (author)

  11. High pressure effects in anaesthesia and narcosis.

    Science.gov (United States)

    Wlodarczyk, Agnieszka; McMillan, Paul F; Greenfield, Susan A

    2006-10-01

    There is growing interest in determining the effects of high pressure on biological functions. Studies of brain processes under hyperbaric conditions can give a unique insight into phenomena such as nitrogen narcosis, inert gas anaesthesia, and pressure reversal of the effects of anaesthetic and narcotic agents. Such research may shed light on the action of anaesthetics, which remains poorly understood, and on the nature of consciousness itself. Various studies have established the behavioural response of organisms to hyperbaric conditions, in the presence or absence of anaesthetic agents. At the molecular level, X-ray crystallography has been used to investigate the incorporation of species like Xe in hydrophobic pockets within model ion channels that may account for pressure effects on neuronal transmission. New magnetic resonance imaging techniques are providing tomographic three-dimensional images that detail brain structure and function, and that can be correlated with behavioural studies and psychological test results. Such whole organ techniques are linked to the molecular scale via voltage-sensitive dye (VSD) imaging studies on brain slices that provide time-resolved images of the dynamic formation and interconnection of inter-neuronal complexes. The VSD experiments are readily adapted to in situ studies under high pressure conditions. In this tutorial review we review the current state of knowledge of hyperbaric effects on brain processes: anaesthesia and narcosis, recent studies at the molecular level via protein crystallography at high pressure in a Xe atmosphere, and we also present some preliminary results of VSD imaging of brain slices under hyperbaric conditions.

  12. 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.

  13. 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

  14. Microwave-assisted wet digestion with H2O2 at high temperature and pressure using single reaction chamber for elemental determination in milk powder by ICP-OES and ICP-MS.

    Science.gov (United States)

    Muller, Edson I; Souza, Juliana P; Muller, Cristiano C; Muller, Aline L H; Mello, Paola A; Bizzi, Cezar A

    2016-08-15

    In this work a green digestion method which only used H2O2 as an oxidant and high temperature and pressure in the single reaction chamber system (SRC-UltraWave™) was applied for subsequent elemental determination by inductively coupled plasma-based techniques. Milk powder was chosen to demonstrate the feasibility and advantages of the proposed method. Samples masses up to 500mg were efficiently digested, and the determination of Ca, Fe, K, Mg and Na was performed by inductively coupled plasma optical emission spectrometry (ICP-OES), while trace elements (B, Ba, Cd, Cu, Mn, Mo, Pb, Sr and Zn) were determined by inductively coupled plasma mass spectrometry (ICP-MS). Residual carbon (RC) lower than 918mgL(-1) of C was obtained for digests which contributed to minimizing interferences in determination by ICP-OES and ICP-MS. Accuracy was evaluated using certified reference materials NIST 1549 (non-fat milk powder certified reference material) and NIST 8435 (whole milk powder reference material). The results obtained by the proposed method were in agreement with the certified reference values (t-test, 95% confidence level). In addition, no significant difference was observed between results obtained by the proposed method and conventional wet digestion using concentrated HNO3. As digestion was performed without using any kind of acid, the characteristics of final digests were in agreement with green chemistry principles when compared to digests obtained using conventional wet digestion method with concentrated HNO3. Additionally, H2O2 digests were more suitable for subsequent analysis by ICP-based techniques due to of water being the main product of organic matrix oxidation. The proposed method was suitable for quality control of major components and trace elements present in milk powder in consonance with green sample preparation. Copyright © 2016 Elsevier B.V. All rights reserved.

  15. High-pressure Brillouin study on methane hydrate

    CERN Document Server

    Sasaki, S; Suwa, I; Kume, T; Shimizu, H

    2002-01-01

    Acoustic velocities and adiabatic elastic constants of structure I of methane hydrate (MH) have been determined as a function of pressure up to 0.6 GPa at 23 deg. C by the high-pressure Brillouin spectroscopy developed for a single molecular crystal. The pressure dependence of the acoustic velocities of MH is very similar to that of ice-Ih except for the longitudinal acoustic (LA) velocity. The value of the LA velocity along the (100) direction of MH at 0.02 GPa is 3.63 km s sup - sup 1 which is about 7% lower than the average of the LA velocities in the ice-Ih phase at -35.5 deg. C and atmospheric pressure.

  16. Photophysics of organic molecules at high pressure

    Energy Technology Data Exchange (ETDEWEB)

    Mitchell, Dean James [Univ. of Illinois, Urbana-Champaign, IL (United States)

    1978-01-01

    The pressure dependence of emission intensities, energies, and lifetimes of several classes of organic compounds in plastic media were investigated over the range 0-140 kilobars. The fluorescence intensity of 9-anthraldehyde, 9-acetylanthracene, and 9-benzoylanthracene increases remarkably with increasing pressure, accompanied by a large red shift in the emission spectrum. For azulene and several derivatives, the efficiency of fluorescence from both the second and first excited singlet states was pressure dependent as was the relative energy of these states. The rate of internal conversion depended strongly on the energy separating the relevant states. The energy and quantum efficiency of fluorescence for fluorenone in crystalline form and in several polymeric matrices was measured as a function of pressure. The quantum yield, ranged from 0.001 at low pressure to a maximum of about 0.1 at high pressure in paraffinic plastics. Fluorescence quantum yields and phosphorescence quantum yields and lifetimes were measured for pyrazine (P) 2,6-dimethylpyrazine and tetramethylpyrazine (TMP) in PMMA over the pessure range 20-120 kbar. An additional emission, which is attributed to excimer fluorescence, was also observed for these samples and for crystalline pyrazine. The phosphorescence radiative lifetime for P and TMP was about 18 ms.

  17. 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.

  18. 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.

  19. 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)

  20. 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...

  1. 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

  2. Sintering of zirconia in high-pressure

    International Nuclear Information System (INIS)

    Kunrath, A.O.; Strohaecker, T.R.; Pereira, A.S.; Jornada, J.A.H. da; Piermarini, G.J.

    1989-01-01

    A systematic study about the sintering of zirconia hyperfines powders in high-pressure is presented. The differents conditions effect of sintering in microstructure and in hardness and tenacity properties of zirconia samples with a very fine grain is also studied. (C.G.C.) [pt

  3. 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.

  4. 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.

  5. Advanced Synchrotron Techniques at High Pressure Collaborative Access Team (HPCAT)

    Science.gov (United States)

    Shen, G.; Sinogeikin, S. V.; Chow, P.; Kono, Y.; Meng, Y.; Park, C.; Popov, D.; Rod, E.; Smith, J.; Xiao, Y.; Mao, H.

    2012-12-01

    High Pressure Collaborative Access Team (HPCAT) is dedicated to advancing cutting-edge, multidisciplinary, high-pressure science and technology using synchrotron radiation at Sector 16 of the Advanced Photon Source (APS) of Argonne National Laboratory. At HPCAT an array of novel x-ray diffraction and spectroscopic techniques has been integrated with high pressure and extreme temperature instrumentation for studies of structure and materials properties at extreme conditions.. HPCAT consists of four active independent beamlines performing a large range of various experiments at extreme conditions. 16BM-B beamline is dedicated to energy dispersive and white Laue X-ray diffraction. The majority of experiments are performed with a Paris-Edinburgh large volume press (to 7GPa and 2500K) and include amorphous and liquid structure measurement, white beam radiography, elastic sound wave velocity measurement of amorphous solid materials, with viscosity and density measurement of liquid being under development. 16BM-D is a monochromatic diffraction beamline for powder and single crystal diffraction at high pressure and high (resistive heating) / low (cryostats) temperature. The additional capabilities include high-resolution powder diffraction and x-ray absorption near edge structure (XANES) spectroscopy. The insertion device beamline of HPCAT has two undulators in canted mode (operating independently) and LN cooled Si monochromators capable of providing a large range of energies. 16IDB is a microdiffraction beamline mainly focusing on high-pressure powder and single crystal diffraction in DAC at high temperatures (double-sided laser heating and resistive heating) and low temperature (various cryostats). The modern instrumentation allows high-quality diffraction at megabar pressures from light element, fast experiments with pulsed laser heating, fast dynamic experiments with Pilatus detector, and so on. 16ID-D beamline is dedicated to x-ray scattering and spectroscopy research

  6. High-pressure Brillouin scattering in a simple molecular system

    CERN Document Server

    Shimizu, H

    2002-01-01

    Recent developments in high-pressure in situ Brillouin spectroscopy of a simple molecular system are reviewed by demonstrating experimental and analytical methods for the study of acoustic velocities in any direction, adiabatic elastic constants, and elastic anisotropy. Detailed applications to solid argon (Ar) are presented, at pressures up to 70 GPa in a diamond anvil cell, using recently developed approaches that combine the method of in situ Brillouin spectroscopy, for a single crystal of Ar up to 4 GPa, and the envelope method applied to both longitudinal acoustic and transverse acoustic modes, for recrystallized Ar between 4 and 70 GPa.

  7. High pressure cell for neutron scattering experiments

    International Nuclear Information System (INIS)

    Shinde, A.B.; Krishna, P.S.R.; Paranjpe, S.K.; Vaidya, S.N.

    1997-01-01

    We report here the design and fabrication of a high pressure clamped cell using EN45 steel for neutron scattering experiments up to 15 kbar. The pressure cell geometry allows detection of scattered neutrons in a plane over an angular range of 90 deg. The cell can be used for both elastic and inelastic scattering measurements on polycrystalline materials and disordered materials. The volume of the sample region is about 400 mm 3 . Preliminary results obtained from neutron diffraction of ND 4 I and KNO 3 are presented. (author)

  8. High pressure hydroformylation in the chemical industry

    Energy Technology Data Exchange (ETDEWEB)

    Paciello, R. [BASF Aktiengesellschaft, Ludwigshafen (Germany)

    2006-07-01

    Higher oxo alcohols are intermediates for large-scale applications, such as plasticizers, detergents and fuel additives, as well as being useful in the synthesis of fine chemicals such as vitamins or flavors and fragrances. Many of these alcohols are still made using high pressure technologies. Advantages and disadvantages of different technologies presently in use or being developed are discussed. In particular, efforts to decrease raw material costs, e.g. by increasing yield, or investment, e.g. by decreasing pressure, will be highlighted. (orig.)

  9. Extremely-high vacuum pressure measurement by laser ionization

    International Nuclear Information System (INIS)

    Kokubun, Kiyohide

    1991-01-01

    Laser ionization method has the very high sensitivity for detecting atoms and molecules. Hurst et al. successfully detected a single Cs atom by means of resonance ionization spectroscopy developed by them. Noting this high sensitivity, the authors have attempted to apply the laser ionization method to measure gas pressure, particularly in the range down to extremely high vacuum. At present, hot cathode ionization gauges are used for measuring gas pressure down to ultrahigh vacuum, however, those have a number of disadvantages. The pressure measurement using lasers does not have such disadvantages. The pressure measurement utilizing the laser ionization method is based on the principle that when laser beam is focused through a lens, the amount of atom or molecule ions generated in the focused space region is proportional to gas pressure. In this paper, the experimental results are presented on the nonresonant multiphoton ionization characteristics of various kinds of gases, the ion detection system with high sensitivity and an extremely high vacuum system prepared for the laser ionization experiment. (K.I.)

  10. 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

  11. A high temperature high pressure cell for quasielastic neutron scattering.

    Science.gov (United States)

    Yang, F; Kaplonski, J; Unruh, T; Mamontov, E; Meyer, A

    2011-08-01

    We present our recent development of a high temperature high pressure cell for neutron scattering. Combining a water cooled Nb1Zr pressure cell body with an internal heating furnace, the sample environment can reach temperatures of up to 1500 K at a pressure of up to 200 MPa at the sample position, with an available sample volume of about 700 mm(3). The cell material Nb1Zr is specifically chosen due to its reasonable mechanical strength at elevated temperatures and fairly small neutron absorption and incoherent scattering cross sections. With this design, an acceptable signal-to-noise ratio of about 10:1 can be achieved. This opens new possibilities for quasielastic neutron scattering studies on different types of neutron spectrometers under high temperature high pressure conditions, which is particularly interesting for geological research on, e.g., water dynamics in silicate melts.

  12. Phosphorus Dimerization in Gallium Phosphide at High Pressure

    Energy Technology Data Exchange (ETDEWEB)

    Lavina, Barbara [High Pressure Science and Engineering Center, University of Nevada, Las Vegas, Nevada 89154, United States; Department of Physics and Astronomy, University of Nevada, Las Vegas, Nevada 89154, United States; Kim, Eunja [Department of Physics and Astronomy, University of Nevada, Las Vegas, Nevada 89154, United States; Cynn, Hyunchae [Lawrence Livermore National Laboratory, Livermore, California 94550, United States; Weck, Philippe F. [Sandia National Laboratories, Albuquerque, New Mexico 87185, United States; Seaborg, Kelly [High Pressure Science and Engineering Center, University of Nevada, Las Vegas, Nevada 89154, United States; Department of Physics and Astronomy, University of Nevada, Las Vegas, Nevada 89154, United States; Siska, Emily [High Pressure Science and Engineering Center, University of Nevada, Las Vegas, Nevada 89154, United States; Meng, Yue [HPCAT, Carnegie Institution of Washington, Argonne, Illinois 60439, United States; Evans, William [Lawrence Livermore National Laboratory, Livermore, California 94550, United States

    2018-02-09

    Using combined experimental and computational approaches, we show that at 43 GPa and 1300 K gallium phosphide adopts the super-Cmcm structure, here indicated with its Pearson notation oS24. First-principles enthalpy calculations demonstrate that this structure is more thermodynamically stable above ~20 GPa than previously proposed polymorphs. Here, in contrast to other polymorphs, the oS24 phase shows a strong bonding differentiation and distorted fivefold coordination geometries of both P atoms. The shortest bond of the phase is a single covalent P–P bond measuring 2.171(11) Å at synthesis pressure. Phosphorus dimerization in GaP sheds light on the nature of the super-Cmcm phase and provides critical new insights into the high-pressure polymorphism of octet semiconductors. Bond directionality and anisotropy explain the relatively low symmetry of this high-pressure phase.

  13. 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.

  14. 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...

  15. Inspection technology for high pressure pipes

    International Nuclear Information System (INIS)

    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)

  16. 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 film...... 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....

  17. Effects of the DASH-JUMP dietary intervention in Japanese participants with high-normal blood pressure and stage 1 hypertension: an open-label single-arm trial

    OpenAIRE

    Kawamura, Atsuko; Kajiya, Katsuko; Kishi, Hiroko; Inagaki, Junko; Mitarai, Makoto; Oda, Hiroshi; Umemoto, Seiji; Kobayashi, Sei

    2016-01-01

    The Dietary Approaches to Stop Hypertension (DASH) diet is recommended by the American Heart Association to lower blood pressure (BP); however, its effects in Japanese participants have not been rigorously studied. We assessed the effects of the DASH-Japan Ube Modified diet Program (DASH-JUMP), a modified DASH diet, on cardiometabolic and inflammatory biomarkers in Japanese participants with untreated high-normal BP or stage 1 hypertension. Fifty-eight participants (30 men and 28 women; mean ...

  18. 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.

  19. Application of High Pressures to Ceramics.

    Science.gov (United States)

    1981-10-13

    made, while at the same time , be healed, for example, by lIPing. However, the high toughness of the resultant composite much broader application of...deformation of high dialational stresses sufficiently relaxes ceramics is apparently not currently being the matrix constraint so the particles...same time maintaining single crystal particulates, it may be even more applicabli quality in terms of purity and the absence of to development of such

  20. High-pressure direct synthesis of aluminium nitride

    CERN Document Server

    Bockowski, M; Grzegory, I; Krukowski, S; Wróblewski, M; Porowski, S

    2002-01-01

    We report the results of direct synthesis of aluminium nitride (AlN) under high nitrogen pressure up to 1 GPa and temperatures up to 2000 K. At pressure from 10 to 650 MPa we observe the combustion synthesis of AlN. As the result of the combustion process one can obtain the AlN sintered powder or AlN/Al metal matrix composites. For N sub 2 pressure higher than 650 MPa the crystal growth of AlN from the solution of atomic nitrogen in aluminium is possible. Both needle-like and bulk AlN single crystals, up to 1 cm and 1 mm, respectively, have been obtained.

  1. Dietary spermidine for lowering high blood pressure

    Science.gov (United States)

    Eisenberg, Tobias; Abdellatif, Mahmoud; Zimmermann, Andreas; Schroeder, Sabrina; Pendl, Tobias; Harger, Alexandra; Stekovic, Slaven; Schipke, Julia; Magnes, Christoph; Schmidt, Albrecht; Ruckenstuhl, Christoph; Dammbrueck, Christopher; Gross, Angelina S.; Herbst, Viktoria; Carmona-Gutierrez, Didac; Pietrocola, Federico; Pieber, Thomas R.; Sigrist, Stephan J.; Linke, Wolfgang A.; Mühlfeld, Christian; Sadoshima, Junichi; Dengjel, Joern; Kiechl, Stefan; Kroemer, Guido; Sedej, Simon; Madeo, Frank

    2017-01-01

    ABSTRACT Loss of cardiac macroautophagy/autophagy impairs heart function, and evidence accumulates that an increased autophagic flux may protect against cardiovascular disease. We therefore tested the protective capacity of the natural autophagy inducer spermidine in animal models of aging and hypertension, which both represent major risk factors for the development of cardiovascular disease. Dietary spermidine elicits cardioprotective effects in aged mice through enhancing cardiac autophagy and mitophagy. In salt-sensitive rats, spermidine supplementation also delays the development of hypertensive heart disease, coinciding with reduced arterial blood pressure. The high blood pressure-lowering effect likely results from improved global arginine bioavailability and protection from hypertension-associated renal damage. The polyamine spermidine is naturally present in human diets, though to a varying amount depending on food type and preparation. In humans, high dietary spermidine intake correlates with reduced blood pressure and decreased risk of cardiovascular disease and related death. Altogether, spermidine represents a cardio- and vascular-protective autophagy inducer that can be readily integrated in common diets. PMID:28118075

  2. 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)

  3. Superconductivity from magnetic elements under high pressure

    Energy Technology Data Exchange (ETDEWEB)

    Shimizu, Katsuya [KYOKUGEN, Research Center for Materials Science at Extreme Conditions, Osaka University, Osaka 560-8531 (Japan)]. E-mail: shimizu@rcem.osaka-u.ac.jp; Amaya, Kiichi [Toyota Physical and Chemical Research Institute, Aichi 480-1192 (Japan); Suzuki, Naoshi [Graduate School of Engineering Science, Osaka University, Osaka 560-8531 (Japan); Onuki, Yoshichika [Graduate School of Science, Osaka University, Osaka 560-0043 (Japan)

    2006-05-01

    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.

  4. 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

  5. 30 CFR 57.13021 - High-pressure hose connections.

    Science.gov (United States)

    2010-07-01

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

  6. 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.

  7. Normal Shocks with High Upstream Pressure

    Science.gov (United States)

    Sirignano, William

    2017-11-01

    A normal compressive shockwave with supercritical upstream thermodynamic conditions is analyzed using Soave-Redlich-Kwong equation of state for real-gas density, enthalpy, and entropy relations for argon, nitrogen, oxygen, and carbon dioxide. Upstream pressure and temperature varying from 10 to 500 bar and 160 to 800 K. At high pressures, the flow does not follow the calorically-perfect-gas behavior. For the perfect gas, the enthalpy and ratio of pressure-to-density are directly proportional to the square of the sound speed, allowing its direct substitution in the conservation equations. A new thermodynamic function is identified for the sound speed which is shown to remain as the proper characteristic speed. Although the sound speed does not emerge directly from the conservation equations as it does for a perfect gas, the shock speed goes to this limiting value as shock strength goes to zero. For the real-gas, modifications are obtained for Prandtl's relation and the Rankine-Hugoniot relation. The modified real-gas Riemann invariants are constructed and discussed for application to weak shocks. A foundation is presented for use with other cubic equations of state, multicomponent flows, and / or for more complex flow configurations. Support from AFOSR, Dr. Mitat Birkan, Program manger.

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

    Science.gov (United States)

    2010-10-01

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

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

    Directory of Open Access Journals (Sweden)

    Syuma Yasuzuka and Keizo Murata

    2009-01-01

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

  10. Condensed matter at high shock pressures

    International Nuclear Information System (INIS)

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

    1985-01-01

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

  11. High temperature and pressure alkaline electrolysis

    DEFF Research Database (Denmark)

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

    2013-01-01

    and pressures. Two measurement systems were built to perform measurements under high pressures and at elevated temperatures of up to 95 bar and 250 °C, respectively. The conductivity of aqueous KOH and aqueous KOH immobilized in a porous SrTiO3 structure were investigated at elevated temperatures and high...... concentrations of the electrolyte using the van der Pauw method in combination with electrochemical impedance spectroscopy (EIS). Conductivity values as high as 2.9 S cm-1 for 45 wt% KOH aqueous KOH and 0.84 S cm-1 for the immobilized KOH of the same concentration were measured at 200 °C. Porous SrTiO3 was used...... for immobilization of aqueous KOH solutions. Electrolysis cells with this electrolyte and metal foam based gas diffusion electrodes were successfully demonstrated at temperatures up to 250 °C at 40 bar. Different electro-catalysts were tested in order to reduce the oxygen and hydrogen overpotentials. Current...

  12. Conformable pressure vessel for high pressure gas storage

    Science.gov (United States)

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

    2016-01-12

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

  13. 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

  14. [Hypertensive urgency or high blood pressure variability?

    Science.gov (United States)

    Rodionov, A V

    Hypertensive urgency (HU) is a common reason particularly for elderly patients to seek medical advice. Severe asymptomatic hypertension and situational high blood pressure (BP) in patients with its high variability is frequently taken as HU. The use of short-acting antihypertensive drugs is not only indicated in these situations, but it may also increase the risk of cardiovascular events (CVE). Over the past decade, increased BP variability is an independent predictor for a higher risk of CVE. Among the major groups of antihypertensive drugs, there are calcium antagonists, mainly amlodipine, which has the greatest potential to reduce BP variability. Thus, calcium antagonists can be considered as first-line drugs for patients with high BP variability.

  15. 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.

  16. High pressure phases of alkali ternary borohydrides

    Science.gov (United States)

    Kumar, Ravhi; Cornelius, Andrew

    2007-03-01

    Insitu synchrotron x-ray diffraction experiments were carried out on MBH4 (M = K and Rb) borohydrides at high pressures up to 26 GPa using diamond anvil cells. KBH4 undergoes a structural transition at 4 GPa to a tetragonal phase from cubic and then to an orthorhombic phase around 7 GPa which are very similar to NaBH4 investigated earlier [1]. However, RbBH4 shows, a direct transition from the ambient cubic to an orthorhombic phase at 2.9 GPa, followed by a monoclinic phase at 8 GPa. Complementary high pressure Raman experiments, support the transitions observed in the diffraction experiments. The results will be presented in detail. [1]. Ravhi S. Kumar and Andrew L. Cornelius, Appl.Phys.Lett., 87,261916 (2005) This work is supported in part by the U.S. Department of Energy (DOE) under Award Number DE-FG36 05GO85028. HPCAT is supported by DOE-BES, DOE-NNSA,NSF, and the W.M. Keck Foundation.

  17. High-pressure structures of yttrium hydrides

    Science.gov (United States)

    Liu, Lu-Lu; Sun, Hui-Juan; Wang, C. Z.; Lu, Wen-Cai

    2017-08-01

    In this work, the crystal structures of YH3 and YH4 at high pressure (100-250 GPa) have been explored using a genetic algorithm combined with first-principles calculations. New structures of YH3 with space group symmetries of P21/m and I4/mmm were predicted. The electronic structures and the phonon dispersion properties of various YH3 and YH4 structures at different temperatures and pressures were investigated. Among YH3 phases, the P21/m structure of YH3 was found to have a relatively high superconducting transformation temperature T c of 19 K at 120 GPa, which is reduced to 9 K at 200 GPa. Other YH3 structures have much lower T cs. Compared with YH3, the T c of the YH4 compound is much higher, i.e. 94 K at 120 GPa and 55 K at 200 GPa.

  18. Failure analysis of high strength pipeline with single and multiple corrosions

    International Nuclear Information System (INIS)

    Chen, Yanfei; Zhang, Hong; Zhang, Juan; Li, Xin; Zhou, Jing

    2015-01-01

    Highlights: • We study failure of high strength pipelines with single corrosion. • We give regression equations for failure pressure prediction. • We propose assessment procedure for pipelines with multiple corrosions. - Abstract: Corrosion will compromise safety operation of oil and gas pipelines, accurate determination of failure pressure finds importance in residual strength assessment and corrosion allowance design of onshore and offshore pipelines. This paper investigates failure pressure of high strength pipeline with single and multiple corrosions using nonlinear finite element analysis. On the basis of developed regression equations for failure pressure prediction of high strength pipeline with single corrosion, the paper proposes an assessment procedure for predicting failure pressure of high strength pipeline with multiple corrosions. Furthermore, failure pressures predicted by proposed solutions are compared with experimental results and various assessment methods available in literature, where accuracy and versatility are demonstrated

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

    Directory of Open Access Journals (Sweden)

    S.Hosokawa

    2008-03-01

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

  20. [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.

  1. Pressure estimation from single-snapshot tomographic PIV in a turbulent boundary layer

    NARCIS (Netherlands)

    Schneiders, J.F.G.; Pröbsting, S.; Dwight, R.P.; Van Oudheusden, B.W.; Scarano, F.

    2016-01-01

    A method is proposed to determine the instantaneous pressure field from a single tomographic PIV velocity snapshot and is applied to a flat-plate turbulent boundary layer. The main concept behind the single-snapshot pressure evaluation method is to approximate the flow acceleration using the

  2. Exotic magnetic structures in high-pressure synthesized perovskites

    Science.gov (United States)

    Manuel, Pascal; Khalyavin, Dmitry; Ding, Lei; Yi, Wei; Kumagai, Yu; Oba, Fumiyasu; Orlandi, Fabio; Belik, Alexei

    We present a neutron powder diffraction study of the crystal and magnetic structures of the high-pressure stabilized perovskite phases of TlMnO3, ScCrO3, InCrO3 and TlCrO3. These compounds exhibit original magnetic structures compared to other members of their respective manganite and orthochromite families with TlMnO3 also displaying unusual orbital ordering pattern. For both systems, we rationalise the structures through a combination of group theory and first principle calculations. We also highlight the dominant mechanism controlling the spin direction as being the single ion anisotropy.

  3. 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.

  4. How to Prevent High Blood Pressure

    Science.gov (United States)

    ... Your diastolic pressure is 100 or higher For children and teens, the health care provider compares the blood pressure reading to what is normal for other kids who are the same age, height, and gender. People with diabetes or chronic kidney disease should keep their blood pressure below 130/80. ...

  5. High-pressure structures of methane hydrate

    CERN Document Server

    Hirai, H; 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 sub 0 , for str. I, str. A, and str. C were calculated to be 7.4, 9.8, and 25.0 GPa, respectively.

  6. 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.

  7. 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.

  8. 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

  9. 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 ...

  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. 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 ...

  12. 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 ...

  13. Effect of high pressure on mesophilic lactic fermentation streptococci

    International Nuclear Information System (INIS)

    Reps, A; Kuzmicka, M; Wisniewska, K

    2008-01-01

    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

  14. Pyridinium salt investigations under high pressure: pressure-induced phase transitions in ferroelectric pyridinium perrhenate

    International Nuclear Information System (INIS)

    Czarnecki, P; Beskrovny, A I; Bobrowicz-Sarga, L; Lewicki, S; Wasicki, J

    2005-01-01

    The properties of pyridinium perrhenate have been studied by three methods: dielectric spectroscopy, neutron powder diffractometry and NMR spectrometry under high pressure. It has been shown that under high pressure the temperatures of the two phase transitions in the crystal are shifted towards lower ones. Moreover, the results have shown the occurrence of a new high pressure phase with a triple point corresponding to the pressure of 100 MPa and the temperature of 240 K

  15. 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.

  16. 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

  17. High-pressure structural stability of the ductile intermetallic ...

    Indian Academy of Sciences (India)

    Keywords. Intermetallics; X-ray diffraction; high pressure; synchrotron radiation. Abstract. High-pressure angle dispersive ... Author Affiliations. S Meenakshi1. High Pressure and Synchrotron Radiation Physics Division, Bhabha Atomic Research Centre, Mumbai 400 085, India. Dates. Manuscript received: 10 July 2013 ...

  18. 30 CFR 56.13021 - High-pressure hose connections.

    Science.gov (United States)

    2010-07-01

    ... 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... 30 Mineral Resources 1 2010-07-01 2010-07-01 false High-pressure hose connections. 56.13021...

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

    Science.gov (United States)

    ... Is it true that sleep deprivation can cause high blood pressure? Answers from Sheldon G. Sheps, M.D. Possibly. It's thought ... night may be at higher risk of developing high blood pressure or worsening already high blood pressure. There's also ...

  20. Probing Hydrogen Diffusion under High Pressure

    Science.gov (United States)

    Bove, L. E.; Klotz, S.; Strassle, T.; Saitta, M.

    2012-12-01

    The study of the microscopic mechanism governing hydrogen and hydrogen-based liquids (as water, ammonia and methane) diffusion is crucial for a variety of scientific issues spanning most of natural sciences. As an example, characterizing hydrogen diffusion in a confined medium, like in porous systems or zeolites, is fundamental in problems relating to environment, hydrogen storage and industrial applications [1]. The presence of water diffusion in the minerals of the Earth's mantle have strong incidence on the processes governing volcanic eruptions and intermediate-depth seismicity. As last example, knowing in details the microscopic dynamics of hydrogen-based simple liquids under extreme conditions is essential in order to interpret observations and develop models of planet interiors [2]. On the other hand, water and other simple hydrogen-based liquids have always been key systems in the development of modern condensed-matter physics, because of their simple electronic structure and the peculiar properties deriving from the hydrogen-bond network. Their high compressibility and chemical reactivity have made these systems very challenging to study experimentally under static high P-T conditions. In the last few years, a large effort has been undertaken by several groups around the world [2] to extend the static and dynamic techniques to high temperatures and pressures, a program in which our group has been actively involved [3-6]. However, while the structure of water and other hydrogenated liquids of geological interest, is now known up to almost 20 GPa, the study of their transport properties greatly lags behind. We have recently developed a new large-volume gasket-anvil ensemble for the Paris-Edinburgh press based on a novel toroidal design [7], which allows to perform quasi elastic neutron scattering measurements on hydrogen based liquids up to one order of magnitude higher pressures (5 GPa) respect to what was achievable with standard methods [8]. The large

  1. Investigating cavity pressure behavior in high-pressure RTM process variants

    Science.gov (United States)

    Rosenberg, P.; Chaudhari, R.; Karcher, M.; Henning, F.; Elsner, P.

    2014-05-01

    The paper addresses new variants of the high pressure resin transfer molding (HP-RTM) process namely high pressure injection RTM (HP-IRTM) and high pressure compression RTM (HP-CRTM) for manufacturing of carbon fiber reinforced composites with high fiber volume content. Both these processes utilize high-pressure RTM equipment for precise dosing and mixing of highly reactive epoxy resin and amine hardener with relatively high throughput rates. The paper addresses results of a study which investigated cavity pressure measurement for both the HP-RTM process variants using a specially designed highpressure RTM mold. The investigations indicate that the cavity pressure built up is a characteristic of the selected process variant. Further the relationship between the applied press force and the cavity pressure in HP-CRTM process was studied.

  2. The effect of high pressure on the luminescent properties of coumarin 153

    CERN Document Server

    Li Hong; He Li Ming; Wu Shi Kang; Li Yi; Yang Guo Qiang

    2002-01-01

    A dual-fluorescence emitting behaviour of coumarin 153 powder has been detected at high pressure while at ambient pressure the dye exhibits only single-band emission. Because of the strong electron-withdrawal group at site 7, these two fluorescent peaks can be ascribed to local excited state emission and charge transfer state emission, respectively.

  3. 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.)

  4. Anomalous superconductivity in black phosphorus under high pressures

    International Nuclear Information System (INIS)

    Kawamura, H.; Tachikawa, K.

    1984-01-01

    Pressure induced superconductivity in single crystals of black phosphorus has been studied. Maximum onset Tsub(c) was near 13 K. The anomalous superconductivity may be explained in terms of excitonic mechanism. (author)

  5. High pressure waterjet cutting industrial needs survey

    Science.gov (United States)

    Klavuhn, John; Baker, Bruce

    1989-08-01

    The results are presented of a survey conducted by personnel of the National Center for Excellence in Metalworking Technology (NCEMT) to assess the industrial needs in high pressure water jet cutting (WJC) technology. Survey forms were mailed to approximately 1400 individuals obtained from three mailing lists. The respondents included approximately 200 individuals associated with a variety of industries: 12 percent were WJC equipment suppliers, 40 percent were WJC users, and 48 percent were neither suppliers nor users. The survey addressed five specific areas of WJC technology: research and development, standards, systems, new products, and training and service. Results show that the need having the highest priority is the establishment of a database on WJC that contains the cutting parameters for a wide range of materials. Associated with this objective is the expressed need for an independent demonstration and test center for testing, data generation and operator training. A further need was found for establishing organized efforts in hardware development and research in mechanisms of cutting.

  6. 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.

  7. 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.

  8. Differences in evolutionary pressure acting within highly conserved ortholog groups

    Directory of Open Access Journals (Sweden)

    Aravind L

    2008-07-01

    Full Text Available Abstract Background In highly conserved widely distributed ortholog groups, the main evolutionary force is assumed to be purifying selection that enforces sequence conservation, with most divergence occurring by accumulation of neutral substitutions. Using a set of ortholog groups from prokaryotes, with a single representative in each studied organism, we asked the question if this evolutionary pressure is acting similarly on different subgroups of orthologs defined as major lineages (e.g. Proteobacteria or Firmicutes. Results Using correlations in entropy measures as a proxy for evolutionary pressure, we observed two distinct behaviors within our ortholog collection. The first subset of ortholog groups, called here informational, consisted mostly of proteins associated with information processing (i.e. translation, transcription, DNA replication and the second, the non-informational ortholog groups, mostly comprised of proteins involved in metabolic pathways. The evolutionary pressure acting on non-informational proteins is more uniform relative to their informational counterparts. The non-informational proteins show higher level of correlation between entropy profiles and more uniformity across subgroups. Conclusion The low correlation of entropy profiles in the informational ortholog groups suggest that the evolutionary pressure acting on the informational ortholog groups is not uniform across different clades considered this study. This might suggest "fine-tuning" of informational proteins in each lineage leading to lineage-specific differences in selection. This, in turn, could make these proteins less exchangeable between lineages. In contrast, the uniformity of the selective pressure acting on the non-informational groups might allow the exchange of the genetic material via lateral gene transfer.

  9. Functional Sub-states by High-pressure Macromolecular Crystallography.

    Science.gov (United States)

    Dhaussy, Anne-Claire; Girard, Eric

    2015-01-01

    At the molecular level, high-pressure perturbation is of particular interest for biological studies as it allows trapping conformational substates. Moreover, within the context of high-pressure adaptation of deep-sea organisms, it allows to decipher the molecular determinants of piezophily. To provide an accurate description of structural changes produced by pressure in a macromolecular system, developments have been made to adapt macromolecular crystallography to high-pressure studies. The present chapter is an overview of results obtained so far using high-pressure macromolecular techniques, from nucleic acids to virus capsid through monomeric as well as multimeric proteins.

  10. Menopause and High Blood Pressure: What's the Connection?

    Science.gov (United States)

    ... What's the connection? Is there a connection between menopause and high blood pressure? Answers from Shannon K. ... Tommaso, M.D. Blood pressure generally increases after menopause. Some doctors think this increase suggests that hormonal ...

  11. 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...

  12. Decay properties of high-lying single-particles modes

    NARCIS (Netherlands)

    Beaumel, D; Fortier, S; Gales, S; Guillot, J; LangevinJoliot, H; Laurent, H; Maison, JM; Vernotte, J; Bordewijck, J; Brandenburg, S; Krasznahorkay, A; Crawley, GM; Massolo, CP; Renteria, M; Khendriche, A

    1996-01-01

    The neutron decay of high-lying single-particle states in Ni-64, Zr-90, Sn-120 and (208)pb excited by means of the (alpha,He-3) reaction has been investigated at 120 MeV incident energy using the multidetector EDEN. The characteristics of this reaction are studied using inclusive spectra and angular

  13. Effects of the DASH-JUMP dietary intervention in Japanese participants with high-normal blood pressure and stage 1 hypertension: an open-label single-arm trial.

    Science.gov (United States)

    Kawamura, Atsuko; Kajiya, Katsuko; Kishi, Hiroko; Inagaki, Junko; Mitarai, Makoto; Oda, Hiroshi; Umemoto, Seiji; Kobayashi, Sei

    2016-11-01

    The Dietary Approaches to Stop Hypertension (DASH) diet is recommended by the American Heart Association to lower blood pressure (BP); however, its effects in Japanese participants have not been rigorously studied. We assessed the effects of the DASH-Japan Ube Modified diet Program (DASH-JUMP), a modified DASH diet, on cardiometabolic and inflammatory biomarkers in Japanese participants with untreated high-normal BP or stage 1 hypertension. Fifty-eight participants (30 men and 28 women; mean age 54.1±8.1 years) with untreated high-normal BP or stage 1 hypertension followed the DASH-JUMP (salt 8.0 g per day) for 2 months. After the intervention period, they resumed their usual diets for 4 months. The DASH-JUMP significantly decreased the participants' body mass index values (24.6±3.5 kg m -2 at baseline23.2±3.3 kg m -2 at 2 months, P=0.000), BP (153±14/91±11 mm Hg at baseline130±16/80±9 mm Hg at 2 months, P=0.000 and 139±16/85±10 mm Hg at 6 months, P=0.000), fasting serum glucose level (100±26 mg dl - 1 94±15 mg dl - 1 at 2 months, P=0.003) and fasting insulin level (6.9±5.9 μIU ml -1 4.4±2.7 μIU ml -1 at 2 months, P=0.000). The mean compliance of the participants for the DASH-JUMP diet was 88.5%. The DASH-JUMP diet reduced cardiovascular risk factors and may be an effective nutritional strategy for preventing cardiovascular events.

  14. Single shot high resolution digital holography.

    Science.gov (United States)

    Khare, Kedar; Ali, P T Samsheer; Joseph, Joby

    2013-02-11

    We demonstrate a novel computational method for high resolution image recovery from a single digital hologram frame. The complex object field is obtained from the recorded hologram by solving a constrained optimization problem. This approach which is unlike the physical hologram replay process is shown to provide high quality image recovery even when the dc and the cross terms in the hologram overlap in the Fourier domain. Experimental results are shown for a Fresnel zone hologram of a resolution chart, intentionally recorded with a small off-axis reference beam angle. Excellent image recovery is observed without the presence of dc or twin image terms and with minimal speckle noise.

  15. Dislocations and Plasticity in bcc Transition Metals at High Pressure

    Energy Technology Data Exchange (ETDEWEB)

    Yang, L H; Tang, M; Moriarty, J A

    2009-01-23

    Using first-principles electronic structure calculations, quantum-based atomistic simulations and atomistically informed dislocation dynamics (DD) simulations, we have studied individual dislocation behavior and the multiscale modeling of single-crystal plasticity in the prototype bcc transition metals Ta, Mo and V under both ambient and high pressure conditions. The primary focus in this work is on the pressure-dependent structure, mobility and interaction of a/2<111> screw dislocations, which dominate the plastic deformation properties of these materials. At the electronic scale, first-principles calculations of elasticity, ideal strength and generalized stacking fault energy surfaces have been used to validate quantum-based multi-ion interatomic potentials. At the atomistic scale, these potentials have been used in flexible Green's function boundary condition simulations to study the core structure, Peierls stress {tau}{sub P}, thermally activated kink-pair formation and mobility below {tau}{sub P}, and phonon-drag mobility above {tau}{sub P}. These results have then been distilled into analytic velocity laws and used directly in predictive microscale DD simulations of flow stress and resolved yield stress over wide ranges of pressure, temperature and strain rate.

  16. 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.

  17. Single solid phase extraction method for the simultaneous analysis of polar and non-polar pesticides in urine samples by gas chromatography and ultra high pressure liquid chromatography coupled to tandem mass spectrometry.

    Science.gov (United States)

    Cazorla-Reyes, Rocío; Fernández-Moreno, José Luis; Romero-González, Roberto; Frenich, Antonia Garrido; Vidal, José Luis Martínez

    2011-07-15

    A new multiresidue method has been developed and validated for the simultaneous extraction of more than two hundred pesticides, including non-polar and polar pesticides (carbamates, organochlorine, organophosphorous, pyrethroids, herbicides and insecticides) in urine at trace levels by gas and ultra high pressure liquid chromatography coupled to ion trap and triple quadrupole mass spectrometry, respectively (GC-IT-MS/MS, UHPLC-QqQ-MS/MS). Non-polar and polar pesticides were simultaneously extracted from urine samples by a simple and fast solid phase extraction (SPE) procedure using C(18) cartridges as sorbent, and dichloromethane as elution solvent. Recovery was in the range of 60-120%. Precision values expressed as relative standard deviation (RSD) were lower than 25%. Identification and confirmation of the compounds were performed by the use of retention time windows, comparison of spectra (GC-amenable compounds) or the estimation of the ion ratio (LC-amenable compounds). For GC-amenable pesticides, limits of detection (LODs) ranged from 0.001 to 0.436 μg L(-1) and limits of quantification (LOQs) from 0.003 to 1.452 μg L(-1). For LC-amenable pesticides, LODs ranged from 0.003 to 1.048 μg L(-1) and LOQs ranged from 0.011 to 3.494 μg L(-1). Finally, the optimized method was applied to the analysis of fourteen real samples of infants from agricultural population. Some pesticides such as methoxyfenozide, tebufenozide, piperonyl butoxide and propoxur were found at concentrations ranged from 1.61 to 24.4 μg L(-1), whereas methiocarb sulfoxide was detected at trace levels in two samples. Copyright © 2011 Elsevier B.V. All rights reserved.

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

    International Nuclear Information System (INIS)

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

    1997-09-01

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

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

    Directory of Open Access Journals (Sweden)

    Fengxiang Chen

    2014-01-01

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

  20. 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...

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

    International Nuclear Information System (INIS)

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

    2009-01-01

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

  2. High Performance Single Nanowire Tunnel Diodes

    DEFF Research Database (Denmark)

    Wallentin, Jesper; Persson, Johan Mikael; Wagner, Jakob Birkedal

    Semiconductor nanowires (NWs) have emerged as a promising technology for future electronic and optoelectronic devices. Epitaxial growth of III-V materials on Si substrates have been demonstrated, allowing for low-cost production. As the lattice matching requirements are much less strict than...... for planar growth, many new materials combinations can be grown in a single NW. This opens up exciting opportunities for NW-based high-performance solar cells, where previously inaccessible materials combinations can now be chosen to match the solar spectrum. A key component of a multi-junction solar cell...... NWs were contacted in a NW-FET setup. Electrical measurements at room temperature display typical tunnel diode behavior, with a Peak-to-Valley Current Ratio (PVCR) as high as 8.2 and a peak current density as high as 329 A/cm2. Low temperature measurements show improved PVCR of up to 27.6....

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

    International Nuclear Information System (INIS)

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

    2008-01-01

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

  4. 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)

  5. Cubic silicon carbide and boron nitride as possible primary pressure calibrants for high pressure and temperature scale

    Science.gov (United States)

    Zhuravlev, K. K.; Goncharov, A. F.; Tkachev, S. N.; Prakapenka, V.

    2010-12-01

    K. K. Zhuravlev, A. F. Goncharov Geophysical Laboratory, Carnegie Institution of Washington, 5251 Broad Branch Road NW, Washington DC, 20015 V. Prakapenka, S. N. Tkachev CARS, the University of Chicago, Bldg. 434A, Argonne National Laboratory, 9700 S. Cass. Ave., Argonne, IL 60439 Abstract Since its introduction, ruby-based pressure scale (Mao et al., 1986) has been the most commonly used by the high-pressure scientific community. However, it has limited use at elevated temperatures, due to the weakening and broadening of the ruby fluorescence line. The recent developments in the field of high temperature, high pressure physics and geophysics require some alternative pressure scale, which will be capable of measuring pressures at temperatures up to 3000 K. Cubic boron nitride (cBN) was recently (Goncharov et al., 2005) proposed as the possible pressure calibrant. It has been suggested that the simultaneous use of x-ray diffraction to measure density and Brillouin spectroscopy to obtain elastic properties of the crystal can be used to construct the pressure scale independent of any other pressure standards, i.e. cBN can be a primary pressure calibrant. However, the acoustic velocities of cBN are very close to those of diamond and, therefore, are hard to resolve in experiment at high pressures in diamond-anvil cell. Another possible primary pressure calibrant is cubic silicon carbide (SiC-3C). Its density and elastic parameters are quite different from the diamond ones and it is stable over the broad range of temperatures and pressures (up to 1 Mbar). SiC-3C is transparent and allows the use of Brillouin spectroscopy. Additionally, SiC-3C has two strong Raman lines, which can be used for the optical in situ pressure measurements. We report our experimental data on both cBN and SiC-3C and show that they, indeed, can be used in constructing reliable and accurate high-pressure, high-temperature scale. We performed single crystal x-ray diffraction and Brillouin

  6. Experimental study of single-phase pressure drops in coarse particle beds

    Energy Technology Data Exchange (ETDEWEB)

    Clavier, R., E-mail: remi.clavier@irsn.fr [IRSN Cadarache, Saint Paul-lez-Durance (France); Chikhi, N., E-mail: nourdine.chikhi@irsn.fr [IRSN Cadarache, Saint Paul-lez-Durance (France); Fichot, F., E-mail: florian.fichot@irsn.fr [IRSN Cadarache, Saint Paul-lez-Durance (France); Quintard, M., E-mail: Michel.Quintard@imft.fr [Université de Toulouse, Allée Camille Soula, F-31400 Toulouse (France); INPT, UPS, Allée Camille Soula, F-31400 Toulouse (France); IMFT (Institut de Mécanique des Fluides de Toulouse), Allée Camille Soula, F-31400 Toulouse (France); CNRS, F-31400 Toulouse (France)

    2017-02-15

    Motivated by uncertainty reduction in nuclear debris beds coolability, experiments have been conducted on the CALIDE facility in order to investigate single-phase pressure losses in representative debris beds, i.e., high sphericity (>80%) particle beds with small size dispersion (from 1 mm to 10 mm), for which no validated model exists. In this paper, experimental results are presented and analyzed in order to identify a simple correlation for single-phase flow pressure losses generated in this kind of porous media in reflooding flowing conditions, which cover Darcy to weakly turbulent regimes. In the literature, it has been observed that their behavior can be accurately described by a Darcy–Forchheimer law, involving the sum of a linear term and a quadratic non-linear deviation, with respect to the filtration velocity. Expressions for the coefficients of the linear and quadratic terms are determined by assessing the possibility to evaluate equivalent diameters, i.e., characteristic lengths allowing correct predictions of the linear and quadratic terms by the Ergun equation. It has been observed that the Sauter diameter of particles allows a very precise prediction of the linear term, while the quadratic term can be predicted using the product of the Sauter diameter and a sphericity coefficient as an equivalent diameter.

  7. New primary pressure calibrants for high pressure and temperature scale: SiC-3C and cBN are possible candidates

    Science.gov (United States)

    Zhuravlev, Kirill; Goncharov, Alexander; Prakapenka, Vitali

    2011-03-01

    Since the invention of a diamond-anvil cell, various high-pressure scales for in situ pressure measurements have been realized. Ruby-based pressure scale (Mao et al., 1986) is the best known and high-pressure scientific community has been using it for over two decades. However, it has limited use at elevated temperatures, due to the weakening and broadening of the ruby fluorescence line. The recent developments in the field of high temperature, high pressure physics and geophysics require some alternative pressure scale, capable of measuring pressures at temperatures up to 3000 K. Cubic boron nitride (cBN) was recently proposed as the possible pressure calibrant. It has been suggested that the simultaneous use of x-ray diffraction to measure density and Brillouin spectroscopy to obtain elastic properties of the crystal can be used to construct the pressure scale independent of any other pressure standards. However, the acoustic velocities of cBN are very close to those of diamond and, therefore, are hard to resolve in experiment in diamond-anvil cell. Another possible primary pressure calibrant is cubic silicon carbide (SiC-3C). We performed single crystal x-ray diffraction and Brillouin spectroscopy up to 1 Mbar in pressure at room temperature in the diamond-anvil cell and show that cBN and SiC-3C, indeed, can be used in constructing reliable and accurate high-pressure, high-temperature scale.

  8. Analysis, design and testing of high pressure waterjet nozzles

    Science.gov (United States)

    Mazzoleni, Andre P.

    1996-01-01

    The Hydroblast Research Cell at MSFC is both a research and a processing facility. The cell is used to investigate fundamental phenomena associated with waterjets as well as to clean hardware for various NASA and contractor projects. In the area of research, investigations are made regarding the use of high pressure waterjets to strip paint, grease, adhesive and thermal spray coatings from various substrates. Current industrial methods of cleaning often use ozone depleting chemicals (ODC) such as chlorinated solvents, and high pressure waterjet cleaning has proven to be a viable alternative. Standard methods of waterjet cleaning use hand held or robotically controlled nozzles. The nozzles used can be single-stream or multijet nozzles, and the multijet nozzles may be mounted in a rotating head or arranged in a fan-type shape. We consider in this paper the use of a rotating, multijet, high pressure water nozzle which is robotically controlled. This method enables rapid cleaning of a large area, but problems such as incomplete coverage (e.g. the formation of 'islands' of material not cleaned) and damage to the substrate from the waterjet have been observed. In addition, current stripping operations require the nozzle to be placed at a standoff distance of approximately 2 inches in order to achieve adequate performance. This close proximity of the nozzle to the target to be cleaned poses risks to the nozzle and the target in the event of robot error or the striking of unanticipated extrusions on the target surface as the nozzle sweeps past. Two key motivations of this research are to eliminate the formation of 'coating islands' and to increase the allowable standoff distance of the nozzle.

  9. An Ultra-low Frequency Modal Testing Suspension System for High Precision Air Pressure Control

    Directory of Open Access Journals (Sweden)

    Qiaoling YUAN

    2014-05-01

    Full Text Available As a resolution for air pressure control challenges in ultra-low frequency modal testing suspension systems, an incremental PID control algorithm with dead band is applied to achieve high-precision pressure control. We also develop a set of independent hardware and software systems for high-precision pressure control solutions. Taking control system versatility, scalability, reliability, and other aspects into considerations, a two-level communication employing Ethernet and CAN bus, is adopted to complete such tasks as data exchange between the IPC, the main board and the control board ,and the pressure control. Furthermore, we build a single set of ultra-low frequency modal testing suspension system and complete pressure control experiments, which achieve the desired results and thus confirm that the high-precision pressure control subsystem is reasonable and reliable.

  10. 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.

  11. Anomalous melting behavior of solid hydrogen at high pressures

    OpenAIRE

    Liu, Hanyu; Hernández, Eduardo R.; Yan, Jun; Ma, Yanming

    2013-01-01

    Hydrogen is the most abundant element in the universe, and its properties under conditions of high temperature and pressure are crucial to understand the interior of of large gaseous planets and other astrophysical bodies. At ultra high pressures solid hydrogen has been predicted to transform into a quantum fluid, because of its high zero point motion. Here we report first principles two phase coexistence and Z method determinations of the melting line of solid hydrogen in a pressure range sp...

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

    Science.gov (United States)

    2016-05-27

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

  13. 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.

  14. Design and Development of a Pressure Transducer for High Hydrostatic Pressure Measurements up to 200 MPa

    Science.gov (United States)

    Kumar, Anuj; Yadav, Sanjay; Agarwal, Ravinder

    2017-08-01

    A number of pressure transducers, based on strain gauge, capacitance/inductance type, frequency resonators, are commercially available and are being used for sensing and producing an electrical output proportional to applied pressure. These sensors have their own advantages and limitations due to operational ease, measurement uncertainty and the costs. Strain gauge type transducers are now well established devices for accurate and precise measurement of pressure within measurement uncertainty up to 0.1 % of full scale. In the present research work, an indigenous strain gauge pressure transducer has been designed, developed, tested and calibrated for pressure measurement up to 200 MPa. The measurement uncertainty estimated using the pressure transducer was found better than 0.1 % of full scale. This transducer was developed using four foil type strain gauges, bonded, two in axial direction while other two in radial direction, to the controlled stress zones of a tubular maraging steel active cylinder working also as diaphragm. The strain gages were then connected to a Wheatstone bridge arrangement to measure stress generated strains. The pressure was applied through matching connector designed in the same tubular transducer active element. The threaded unique design in a single piece through collar, ferule and tubing arrangement provides leak proof pressure connections with external devices without using additional seals. The calibration and performance checking of the pressure transducer was carried out using dead weight type national pressure standard using the internationally accepted calibration procedure.

  15. Structural changes in tetracyanoethylene at high pressures: neutron diffraction study

    International Nuclear Information System (INIS)

    Mukhopadhyay, R.; Chaplot, S.L.

    2002-01-01

    We report on structural changes in monoclinic tetracyanoethylene, C 2 (CN) 4 as studied by in situ high-pressure (0-5 GPa) neutron powder diffraction experiments. Structural parameters were obtained by Rietveld profile refinement of the diffraction pattern up to P=2.5 GPa. Above this pressure the width parameter is found to diverge, indicating pressure-induced disordering at 2.5 GPa. The recovered sample, on release of pressure from 5 GPa, is found to have transformed to a graphite-like amorphous structure. The transformation to a graphite-like material has been verified by an independent high-pressure x-ray diffraction experiment. (author)

  16. 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

  17. High Temperature and Pressure Alkaline Electrolysis

    DEFF Research Database (Denmark)

    Allebrod, Frank

    temperatures and pressures. Aqueous potassium hydroxide immobilized electrolyte in porous SrTiO3 was used in those cells. Electrolysis cells with metal foam based gas diffusion electrodes and the immobilized electrolyte were successfully demonstrated at temperatures up to 250 °C and 40 bar. Different electro...

  18. 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...

  19. High pressure inertial focusing for separation and concentration of bacteria at high throughput

    Science.gov (United States)

    Cruz, F. J.; Hjort, K.

    2017-11-01

    Inertial focusing is a phenomenon where particles migrate across streamlines in microchannels and focus at well-defined, size dependent equilibrium points of the cross section. It can be taken into advantage for focusing, separation and concentration of particles at high through-put and high efficiency. As particles decrease in size, smaller channels and higher pressures are needed. Hence, new designs are needed to decrease the pressure drop. In this work a novel design was adapted to focus and separate 1 µm from 3 µm spherical polystyrene particles. Also 0.5 µm spherical polystyrene particles were separated, although in a band instead of a single line. The ability to separate, concentrate and focus bacteria, its simplicity of use and high throughput make this technology a candidate for daily routines in laboratories and hospitals.

  20. A new high pressure phase of sodium formate dihydrate; an experimental and computational study.

    Science.gov (United States)

    Walker, Martin; Morrison, Carole A; Allan, David R; Pulham, Colin R; Marshall, William G

    2007-05-28

    As part of an on-going programme to study the high pressure structural behaviour of hydrated small molecular systems, sodium formate dihydrate has been studied using high pressure single crystal X-ray and neutron powder diffraction methods. A new phase was initially identified at 17 kbar by X-ray diffraction and high level quantum mechanical calculations completed the structure, allowing definitive hydrogen atom positioning. The resulting structure compared favourably with that found subsequently by high pressure neutron diffraction. The neutron diffraction study also revealed that the deuterated form, NaDCO(2).2D(2)O, is stable in a different structural form to that of the non-deuterated material at ambient pressure. The structure of this phase is related to that of the high pressure phase via a simple translation of the molecular layers.

  1. A system for incubations at high gas partial pressure

    DEFF Research Database (Denmark)

    Sauer, Patrick; Glombitza, Clemens; Kallmeyer, Jens

    2012-01-01

    at hydrostatic pressure up to 60 MPa, temperatures up to 120°C, and at high gas partial pressure. The composition and partial pressure of gasses can be manipulated during the experiment. To keep costs low, the system is mainly made from off-the-shelf components with only very few custom-made parts. A flexible......High-pressure is a key feature of deep subsurface environments. High partial pressure of dissolved gasses plays an important role in microbial metabolism, because thermodynamic feasibility of many reactions depends on the concentration of reactants. For gases, this is controlled by their partial...... and inert PVDF (polyvinylidene fluoride) incubator sleeve, which is almost impermeable for gases, holds the sample and separates it from the pressure fluid. The flexibility of the incubator sleeve allows for sub-sampling of the medium without loss of pressure. Experiments can be run in both static and flow...

  2. Nanocomposite Thermolectric Materials by High Pressure Powder Consolidation Manufacturing Project

    Data.gov (United States)

    National Aeronautics and Space Administration — In response to NASA's need to develop advanced nanostructured thermolectric materials, UTRON is proposing an innovative high pressure powder consolidation...

  3. 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 ...

  4. Effect of revised high-heeled shoes on foot pressure and static balance during standing

    Science.gov (United States)

    Bae, Young-Hyeon; Ko, Mansoo; Park, Young-Soul; Lee, Suk-Min

    2015-01-01

    [Purpose] The purpose of this study was to investigate the effects of revised high-heeled shoes on the foot pressure ratio and static balance during standing. [Subjects and Methods] A single-subject design was used, 15 healthy women wearing revised high-heeled shoes and general high-heeled shoes in a random order. The foot pressure ratio and static balance scores during standing were measured using a SpaceBalance 3D system. [Results] Forefoot and rearfoot pressures were significantly different between the 2 types of high-heeled shoes. Under the 3 conditions tested, the static balance score was higher for the revised high-heeled shoes than for the general high-heeled shoes, but this difference was not statistically significant. [Conclusion] Revised high-heeled shoes are preferable to general high-heeled shoes, as they result in normalization of normalized foot pressure and a positive effect on static balance. PMID:25995572

  5. Multi-Pulsed High Hydrostatic Pressure Treatment of Foods

    Directory of Open Access Journals (Sweden)

    Sencer Buzrul

    2015-05-01

    Full Text Available Multi-pulsed high hydrostatic pressure (mpHHP treatment of foods has been investigated for more than two decades. It was reported that the mpHHP treatment, with few exceptions, is more effective than the classical or single-pulsed HHP (spHHP treatment for inactivation of microorganisms in fruit juice, dairy products, liquid whole egg, meat products, and sea foods. Moreover, the mpHHP treatment could be also used to inactivate enzymes in foods and to increase the shelf-life of foods. The effects of the mpHHP treatment of foods are summarized and the differences between the mpHHP and spHHP are also emphasized.

  6. [Genesis study of omphacite at high pressure and high temperature].

    Science.gov (United States)

    Xiao, Ben-Fu; Yi, Li; Wang, Duo-Jun; Xie, Chao; Tang, Xue-Wu; Liu, Lei; Cui, Yue-Ju

    2013-11-01

    The melting and recrystallizing experiments of alkali basalt powder and mixture of pure oxides mixed as stoichiometry were performed at 3 GPa and 1 200 degrees C. Electronic microprobe analysis and Raman spectra showed that the recrystallized products were omphacites, the FWHM (full width at half maximum) of the Raman peak was narrow and its shape was sharp, which is attributed to the stable Si-O tetrahedral structure and the high degree of order in omphacite. Based on the results of previous studies, the influencing factors of omphacite genesis and its primary magma were discussed. The results showed that the formation of omphacite could be affected by many factors, such as the composition of parent rocks, the concentration of fluid in the system and the conditions of pressure and temperature. This result could support some experimental evidences on the genesis studies of omphacite and eclogite.

  7. Modeling Study of High Pressure and High Temperature Reservoir Fluids

    DEFF Research Database (Denmark)

    Varzandeh, Farhad

    S-characterization combinations and 260 reservoir fluids. PC-SAFT with the new general characterization method is shown to give the lowest AAD% and maximum deviation in calculation of saturation pressure, density and STO density, among all the tested characterization methods for PC-SAFT. Application of the new characterization...... be highly rewarding if successfully produced. This PhD project is part of the NextOil (New Extreme Oil and Gas in the Danish North Sea) project which is intended to reduce the uncertainties in HPHT field development. The main focus of this PhD is on accurate description of the reservoir fluid behavior under...... HPHT conditions to minimize the production risks from these types of reservoirs. In particular, the study has thoroughly evaluated several non-cubic Equations of State (EoSs) which are considered promising for HPHT fluid modeling, showing their advantages and short comings based on an extensive...

  8. 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

  9. High Pressure Sensing and Dynamics Using High Speed Fiber Bragg Grating Interrogation Systems

    Energy Technology Data Exchange (ETDEWEB)

    Rodriguez, G. [LANL; Sandberg, R. L. [LANL; Lalone, B. M. [NSTec; Marshall, B. R. [NSTec; Grover, M. [NSTec; Stevens, G. D. [NSTec; Udd, E. [Columbia Gorge Research

    2014-06-01

    Fiber Bragg gratings (FBGs) are developing into useful sensing tools for measuring high pressure dynamics in extreme environments under shock loading conditions. Approaches using traditional diode array coupled FBG interrogation systems are often limited to readout speeds in the sub-MHz range. For shock wave physics, required detection speeds approaching 100 MHz are desired. We explore the use of two types of FBG sensing systems that are aimed at applying this technology as embedded high pressure probes for transient shock events. Both approaches measure time resolved spectral shifts in the return light from short (few mm long) uniform FBGs at 1550 nm. In the first approach, we use a fiber coupled spectrometer to demultiplex spectral channels into an array (up to 12) of single element InGaAs photoreceivers. By monitoring the detectors during a shock impact event with high speed recording, we are able to track the pressure induced spectral shifting in FBG down to a time resolution of 20 ns. In the second approach, developed at the Special Technologies Lab, a coherent mode-locked fiber laser is used to illuminate the FBG sensor. After the sensor, wavelength-to-time mapping is accomplished with a chromatic dispersive element, and entire spectra are sampled using a single detector at the modelocked laser repetition rate of 50 MHz. By sampling with a 12 GHz InGaAs detector, direct wavelength mapping in time is recorded, and the pressure induced FBG spectral shift is sampled at 50 MHz. Here, the sensing systems are used to monitor the spectral shifts of FBGs that are immersed into liquid water and shock compressed using explosives. In this configuration, the gratings survive to pressures approaching 50 kbar. We describe both approaches and present the measured spectral shifts from the shock experiments.

  10. High pressure sensing and dynamics using high speed fiber Bragg grating interrogation systems

    Science.gov (United States)

    Rodriguez, G.; Sandberg, R. L.; Lalone, B. M.; Marshall, B. R.; Grover, M.; Stevens, G.; Udd, E.

    2014-06-01

    Fiber Bragg gratings (FBGs) are developing into useful sensing tools for measuring high pressure dynamics in extreme environments under shock loading conditions. Approaches using traditional diode array coupled FBG interrogation systems are often limited to readout speeds in the sub-MHz range. For shock wave physics, required detection speeds approaching 100 MHz are desired. We explore the use of two types of FBG sensing systems that are aimed at applying this technology as embedded high pressure probes for transient shock events. Both approaches measure time resolved spectral shifts in the return light from short (few mm long) uniform FBGs at 1550 nm. In the first approach, we use a fiber coupled spectrometer to demultiplex spectral channels into an array (up to 12) of single element InGaAs photoreceivers. By monitoring the detectors during a shock impact event with high speed recording, we are able to track the pressure induced spectral shifting in FBG down to a time resolution of 20 ns. In the second approach, developed at the Special Technologies Lab, a coherent mode-locked fiber laser is used to illuminate the FBG sensor. After the sensor, wavelength-to-time mapping is accomplished with a chromatic dispersive element, and entire spectra are sampled using a single detector at the modelocked laser repetition rate of 50 MHz. By sampling with a 12 GHz InGaAs detector, direct wavelength mapping in time is recorded, and the pressure induced FBG spectral shift is sampled at 50 MHz. Here, the sensing systems are used to monitor the spectral shifts of FBGs that are immersed into liquid water and shock compressed using explosives. In this configuration, the gratings survive to pressures approaching 50 kbar. We describe both approaches and present the measured spectral shifts from the shock experiments.

  11. 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)

  12. Explosives under pressure - the crystal structure of gamma-RDX as determined by high-pressure X-ray and neutron diffraction

    OpenAIRE

    Davidson, A.J.; Oswald, Iain D H; Francis, A.R.; Pulham, Colin

    2008-01-01

    Using a combination of X-ray single crystal and neutron powder diffraction, the crystal structure of the high-pressure γ-form of RDX has been determined at 5.2 GPa and shows that the RDX molecules adopt different conformations compared to the conformation found in the ambient-pressure α-form.

  13. Radiation pressure in galactic disks: stability, turbulence, and winds in the single-scattering limit

    Science.gov (United States)

    Wibking, Benjamin D.; Thompson, Todd A.; Krumholz, Mark R.

    2018-04-01

    The radiation force on dust grains may be dynamically important in driving turbulence and outflows in rapidly star-forming galaxies. Recent studies focus on the highly optically-thick limit relevant to the densest ultra-luminous galaxies and super star clusters, where reprocessed infrared photons provide the dominant source of electromagnetic momentum. However, even among starburst galaxies, the great majority instead lie in the so-called "single-scattering" limit, where the system is optically-thick to the incident starlight, but optically-thin to the re-radiated infrared. In this paper we present a stability analysis and multidimensional radiation-hydrodynamic simulations exploring the stability and dynamics of isothermal dusty gas columns in this regime. We describe our algorithm for full angle-dependent radiation transport based on the discontinuous Galerkin finite element method. For a range of near-Eddington fluxes, we show that the medium is unstable, producing convective-like motions in a turbulent atmosphere with a scale height significantly inflated compared to the gas pressure scale height and mass-weighted turbulent energy densities of ˜0.01 - 0.1 of the midplane radiation energy density, corresponding to mass-weighted velocity dispersions of Mach number ˜0.5 - 2. Extrapolation of our results to optical depths of 103 implies maximum turbulent Mach numbers of ˜20. Comparing our results to galaxy-averaged observations, and subject to the approximations of our calculations, we find that radiation pressure does not contribute significantly to the effective supersonic pressure support in star-forming disks, which in general are substantially sub-Eddington. We further examine the time-averaged vertical density profiles in dynamical equilibrium and comment on implications for radiation-pressure-driven galactic winds.

  14. CARS Diagnostics of High Pressure Combustion - 2. Measurements of NO, H2O and High Pressure Flames

    Science.gov (United States)

    1985-12-01

    R85-956328-F CARS DIAGNOSTICS OF r HIGH PRESSURE COMBUSTION -I MEASUREMENTS OF NO, H 0 AND HIGH PRESSURE FLAMES Final Report J.H. Stufflebeam DTIC I7...High Pressure Flames Final Report ~ 5%~ J. H. Stufflebeam J. A. Shirley December 1985 𔃿** U. S. Army Research Office Contract: DAAG29-83-C-OOO1...ClaIiation, CARS Diagnostics of High Pressure Combustion II 12. PERSONAL AUTHOR(S) Stufflebeam , 7. H., ShirleyJA 113a. TYPE OF REPORT 13b. TIME COVERED

  15. 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)

  16. Structural investigation of ribonuclease A conformational preferences using high pressure protein crystallography

    Energy Technology Data Exchange (ETDEWEB)

    Kurpiewska, Katarzyna, E-mail: kurpiews@chemia.uj.edu.pl [Jagiellonian University, Faculty of Chemistry, Department of Crystal Chemistry and Crystal Physics, Protein Crystallography Group, Ingardena 3, 30-060 Kraków (Poland); Dziubek, Kamil; Katrusiak, Andrzej [Adam Mickiewicz University, Faculty of Chemistry, Department of Materials Chemistry, Umultowska 89b, 61-61 Poznań (Poland); Font, Josep [School of Medical Science, University of Sydney, NSW 2006 (Australia); Ribò, Marc; Vilanova, Maria [Universitat de Girona, Laboratorid’Enginyeria de Proteïnes, Departament de Biologia, Facultat de Ciències, Campus de Montilivi, 17071 Girona (Spain); Lewiński, Krzysztof [Jagiellonian University, Faculty of Chemistry, Department of Crystal Chemistry and Crystal Physics, Protein Crystallography Group, Ingardena 3, 30-060 Kraków (Poland)

    2016-04-01

    Highlights: • A unique crystallographic studies of wild-type and mutated form of the same protein under high pressure. • Compressibility of RNase A molecule is significantly affected by a single amino acid substitution. • High pressure protein crystallography helps understanding protein flexibility and identify conformational substrates. - Abstract: Hydrostatic pressure in range 0.1–1.5 GPa is used to modify biological system behaviour mostly in biophysical studies of proteins in solution. Due to specific influence on the system equilibrium high pressure can act as a filter that enables to identify and investigate higher energy protein conformers. The idea of the presented experiments is to examine the behaviour of RNase A molecule under high pressure before and after introduction of destabilizing mutation. For the first time crystal structures of wild-type bovine pancreatic ribonuclease A and its markedly less stable variant modified at position Ile106 were determined at different pressures. X-ray diffraction experiments at high pressure showed that the secondary structure of RNase A is well preserved even beyond 0.67 GPa at room temperature. Detailed structural analysis of ribonuclease A conformation observed under high pressure revealed that pressure influences hydrogen bonds pattern, cavity size and packing of molecule.

  17. Laser-generated shockwave experiments at extreme high pressures

    International Nuclear Information System (INIS)

    Trainor, R.J.; Holmes, N.C.; More, R.M.

    1979-01-01

    The application of high-power lasers to production of extreme high pressures is discussed. Shock velocities consistent with pressures up to 2 TPa in aluminum have already been measured, and experiments in the 4 TPa range are now planned. We describe the status of our programs to develop new diagnostic techniques and perform experiments to characterize perturbing influences on the shock

  18. How Potassium Can Help Control High Blood Pressure

    Science.gov (United States)

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

  19. 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 ...

  20. How High Blood Pressure Can Lead to Stroke

    Science.gov (United States)

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

  1. Changes You Can Make to Manage High Blood Pressure

    Science.gov (United States)

    ... Aneurysm More Changes You Can Make to Manage High Blood Pressure Updated:Mar 2,2018 Fighting back against the “ ... Doctor (PDF) Find More Resources and Fact Sheets High Blood Pressure • Home • Get the Facts About HBP • Know Your ...

  2. 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 ...

  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. High Pressure, Anharmonic Thermoelasticity of Tantalum

    Science.gov (United States)

    Orlikowski, Daniel; Soderlind, Per; Moriarty, John A.

    2003-03-01

    The elastic moduli for bcc tantalum have been investigated over broad ranges of pressure (10 Mbar) and temperature (12,000 K), using first-principles methods that account for the cold, electron- and ion-thermal contributions. In this approach, the full potential linear muffin-tin orbital (FP-LMTO) method for the cold and electron-thermal contributions is combined with closely coupled atomistic simulations for the ion-thermal contribution, using quantum-based interatomic potentials derived from model generalized pseudopotential theory (MGPT) for the latter. While the harmonic part of the ion-thermal contribution can be readily obtained from strain derivatives of quasi-harmonic phonons, we have developed a more general Monte Carlo (MC) simulation method for the corresponding anharmonic part. The MC method directly calculates the elastic moduli through a fluctuation formula comprised of averages in the canonical distribution. Available results will be compared with ultrasonic measurements and diamond-anvil-cell compression experiments as functions of temperature and pressure. Also, the importance of these results in context to larger-scale constitutive models like the Steinberg-Guinan strength model will be discussed. This work was performed under the auspices of the U.S. Department of Energy by the University of California Lawrence Livermore National Laboratory under contract W-7405-Eng-48.

  5. Annealing of GaN under high pressure of nitrogen

    CERN Document Server

    Porowski, S; Kolesnikov, D; Lojkowski, W; Jager, V; Jäger, W; Bogdanov, V; Suski, T; Krukowski, S

    2002-01-01

    Gallium nitride, aluminum nitride and indium nitride are basic materials for blue optoelectronic devices. The essential part of the technology of these devices is annealing at high temperatures. Thermodynamic properties of the Ga-N system and their consequences to application of high nitrogen pressure for the annealing of GaN based materials are summarized. The diffusion of Zn, Mg and Au in high dislocation density heteroepitaxial GaN/Al sub 2 O sub 3 layers will be compared with the diffusion in dislocation-free GaN single crystals and homoepitaxial layers. It will be shown that high dislocation density can drastically change the diffusion rates, which strongly affects the performance of nitride devices. Inter-diffusion of Al, Ga and In in AlGaN/GaN and InGaN/GaN quantum well (QW) structures will be also considered. It will be shown that in contrast to stability of metal contacts, which is strongly influenced by dislocations, the inter-diffusion of group III atoms in QW structures is not affected strongly by...

  6. 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.

  7. Linewidth pressure measurement: a new technique for high vacuum characterization.

    Science.gov (United States)

    Jones, Chad A; Dearden, David V

    2015-02-01

    Pressure measurement is often the limiting factor in the accuracy of quantitative ion-molecule experiments. We present a new method for pressure measurement based on analysis of pressure-limited Fourier transform ion cyclotron resonance (FTICR) linewidths for well-characterized collisions of Ar(+) with Ar. The kinetic energy dependence of Ar(+)/Ar collision cross sections is well-described using a single-parameter fitting procedure, which results in pressure measurements in good agreement with those from a cold cathode tube and from measurement of total ion signal following electron impact ionization. The new method avoids problems inherent in ionization-based methods, such as those arising from differences in ionization potential or perturbations to the pressure that occur during electron ionization of the gas to be measured, and should be applicable in the trapping cells of FTICR and Orbitrap mass spectrometers.

  8. Ultrasonic depth gauge for liquids under high pressure

    Science.gov (United States)

    Zuckerwar, Allan J. (Inventor); Mazel, David S. (Inventor)

    1988-01-01

    The invention relates to an ultrasonic depth gauge for liquids under high pressure and is particularly useful in the space industry where it is necessary to use a pressurized gas to transfer a liquid from one location to another. Conventional liquid depth gauges do not have the capability to operate under extreme high pressure (i.e., exceeding 300 psi). An ultrasonic depth gauge capable of withstanding high pressure according to the present invention is comprised of a transducer assembly and a supporting electronics unit. The former is mounted in to the bottom wall of a storage vessel with its resonating surface directly exposed to the highly pressurized liquid in the vessel. In operation, the ultrasonic pulse propagates upward through the liquid to the liquid-gas interface in the storage vessel. When the ultrasonic echo returns from the liquid-gas interface, it re-excites the composite resonator into vibration. The supporting electronics unit measures the round-trip transmit time for the ultrasonic pulse and its return echo to traverse the depth of the highly pressurized liquid. The novelty of the invention resides in the use of a conventional transducer rigidly bonded to the inside wall of a bored out conventional high-pressure plug to form a composite resonator capable of withstanding extremely high pressure.

  9. Decay properties of high-lying single-particles modes

    Science.gov (United States)

    Beaumel, D.; Fortier, S.; Galès, S.; Guillot, J.; Langevin-Joliot, H.; Laurent, H.; Maison, J. M.; Vernotte, J.; Bordewijck, J.; Brandenburg, S.; Krasznahorkay, A.; Crawley, G. M.; Massolo, C. P.; Renteria, M.; Khendriche, A.

    1996-02-01

    The neutron decay of high-lying single-particle states in 64Ni, 90Zr, 120Sn and 208Pb excited by means of the (α, 3He) reaction has been investigated at 120 MeV incident energy using the multidetector EDEN. The characteristics of this reaction are studied using inclusive spectra and angular correlation analysis. The structure located between 11 and 15 MeV in 91Zr, and between 8 and 12 MeV excitation energy in 209Pb display large departures from a pure statistical decay. The corresponding non-statistical branching ratios are compared with the results of two theoretical calculations.

  10. 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

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

    International Nuclear Information System (INIS)

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

    2008-01-01

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

  12. 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.

  13. High pressure Moessbauer spectroscopy of perovskite iron oxide

    International Nuclear Information System (INIS)

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

    2003-01-01

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

  14. High pressure Moessbauer spectroscopy of perovskite iron oxide

    CERN Document Server

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

    2003-01-01

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

  15. Invitation to neutron scattering study at ultra high pressure

    International Nuclear Information System (INIS)

    Hamaya, Nozomu

    2006-01-01

    Understanding of the pressure evolution of physical and chemical properties of hydrogen is the ultimate goal of the high pressure science. This purpose has simulated the development of low-temperature high-pressure technique for neutron diffraction study. With benefit of high intensity neutron sources a new diamond anvil cell (DAC) has been invented by I.N. Goncharenko. This device allows us to study neutron diffraction under extreme conditions of pressures up to 50 GPa, temperatures down to 0.1 K and applied magnetic fields up to 7.5 T. We describe the details of this technique in the hope that J-PARC (Japan Proton Accelerator Research Complex) will make an epoch in ultra-high-pressure research. (author)

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

    International Nuclear Information System (INIS)

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

    2004-01-01

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

  17. Measurement of shear strength and texture evolution in BCC materials subjected to high pressures

    Science.gov (United States)

    Escobedo, Juan Pablo

    Deformation modeling of metals subjected to extreme pressures and strain rates requires an understanding of the pressure-dependent dislocation core structure and its effect upon dislocation mobility. The core structure and dislocation mobilities can be predicted as a function of applied pressure from sophisticated interatomic potentials calculations and first-principles based atomistic simulations. The goal of the thesis is to develop and implement a testing procedure that experimentally determines pressure-dependent dislocation mobilities in oriented single crystals of the BCC transition metals. These experiments provide calibration data for models of materials subjected to extreme pressures and assist in model validation such as the Steinberg-Guinan hardening model or discrete dislocation dynamics simulations. An experimental procedure is reported to perform shear tests on specimens held under moderately high hydrostatic pressures (on the order of 10 GPa). A thin foil of polycrystalline Ta was used to perform experiments under hydrostatic pressures ranging from 2.1 to 4.2 GPa. A change in texture due to accumulation of slip was observed. Close to a strain of 1, the texture is predicted to change from {111} + {100} to {101}+{121}+{123}, the primary and secondary slip planes in BCC. These {101}+{121}+{123} textures were present in all the samples subjected to pressures greater than the threshold pressure to have internal shearing. The experimental (TEM) evidence shows different microstructures with the pressure being the only variable. At low pressures (2 GPa), an expected microstructure containing only dislocations was found to be responsible for the plastic deformation. At higher pressures (4 GPa) the dislocations appear to arrange themselves into elongated cell walls, with widths of 50-100 nm and lengths close to a micron. Testing on Mo single crystals were carried out. Two different orientations {110} and {121} were tested such that simple shear deformation was

  18. Static internal pressure capacity of Hanford Single-Shell Waste Tanks

    International Nuclear Information System (INIS)

    Julyk, L.J.

    1994-01-01

    Underground single-shell waste storage tanks located at the Hanford Site in Richland, Washington, generate gaseous mixtures that could be ignited, challenging the structural integrity of the tanks. The structural capacity of the single-shell tanks to internal pressure is estimated through nonlinear finite-element structural analyses of the reinforced concrete tank. To determine their internal pressure capacity, designs for both the million-gallon and the half-million-gallon tank are evaluated on the basis of gross structural instability

  19. Static internal pressure capacity of Hanford Single-Shell Waste Tanks

    Energy Technology Data Exchange (ETDEWEB)

    Julyk, L.J.

    1994-07-19

    Underground single-shell waste storage tanks located at the Hanford Site in Richland, Washington, generate gaseous mixtures that could be ignited, challenging the structural integrity of the tanks. The structural capacity of the single-shell tanks to internal pressure is estimated through nonlinear finite-element structural analyses of the reinforced concrete tank. To determine their internal pressure capacity, designs for both the million-gallon and the half-million-gallon tank are evaluated on the basis of gross structural instability.

  20. Decomposition of silicon carbide at high pressures and temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Daviau, Kierstin; Lee, Kanani K. M.

    2017-11-01

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

  1. Pressure dependence of the Hall effect in single crystals of CeNiSn

    International Nuclear Information System (INIS)

    Hiraoka, T.; Kinoshita, E.; Takabatake, T.; Tanaka, H.; Fujii, H.

    1994-01-01

    The pressure dependence of the Hall effect in single crystals of CeNiSn (J parallel b, H parallel a; J parallel a, H parallel b; J parallel b, H parallel c) has been measured. The Hall coefficient R H decreases with pressure in the low-temperature range, indicating a decrease of gap energy under pressure due to the decrease of slope in the log ρ versus 1/T dependence. A crossover temperature is observed in the slope of this dependence. ((orig.))

  2. Impact of balloon inflation pressure on cell viability with single and multi lumen catheters.

    Science.gov (United States)

    Dib, N; Schwalbach, D B; Plourde, B D; Kohler, R E; Dana, D; Abraham, J P

    2014-12-01

    Infusion catheters, when used in combination with balloons, are subjected to pressure created by inflation of the balloon. The compression can reduce the catheter flow area and cause elevated shear stresses in the fluid. A model and experiments were developed with a range of applied balloon pressures to investigate whether such situations may cause cell lysis during stem-cell infusion through single-lumen catheters. It was found that for balloon inflation pressures in excess of ~7 atm, it is possible for cell injury to occur, although the critical pressure depends on the fluid viscosity. The study was then applied to a multi-lumen catheter which was designed to resist compression. That device was able to handle very elevated balloon pressures and flow rates before cell lysis became a concern.

  3. Effect of pressure on the metamagnetic transition of DyB{sub 6} single crystal

    Energy Technology Data Exchange (ETDEWEB)

    Sakai, T. [Department of General Education, Ariake National College of Tecnology, Omuta, Fukuoka 836-8585 (Japan)]. E-mail: sakai@ariake-nct.ac.jp; Oomi, G. [Department of Physics, Kyushu University, Ropponmatsu, Fukuoka 810-8560 (Japan); Uwatoko, Y. [Institute for Solid State Physics, University of Tokyo, Kashiwa, Chiba 277-8581 (Japan); Kunii, S. [Department of Physics, Tohoku University, Sendai, Miyagi 980-8578 (Japan)

    2007-03-15

    The effects of pressure on the magnetization (M) and the magnetostriction (MS) for DyB{sub 6} single crystal have been measured at 4.2 K. It is found that the M loops are insensitive to pressure, whereas the large MS with magnitude of 0.5% at 5 T at ambient pressure is rapidly suppressed by applying pressure. The metamagnetic transition field H {sub M} in the M curve increases slightly by applying pressure with the rate of increase, {partial_derivative} ln H {sub M}/{partial_derivative}P, of 0.03 GPa{sup -1}, which is almost the same value as that for T {sub N}, 0.04 GPa{sup -1}.

  4. Germination of vegetable seeds exposed to very high pressure

    International Nuclear Information System (INIS)

    Mori, Y; Yokota, S; Ono, F

    2012-01-01

    Effects of high hydrostatic pressure were investigated on vegetable seeds in the GPa range to examine the potentialities of breed improvement by high-pressure processing. Specimens of several seeds of broccoli (Brassica oleracea var. italica), Turnip leaf (Brassica rapa var. perviridis) and Potherb Mustard (Brassica rapa var. nipposinica) were put in a teflon capsule with liquid high pressure medium, fluorinate, and inserted into a pyrophillite cube. By using a cubic anvil press a hydrostatic pressure of 5.5 GP a was applied to these seeds for 15 minutes. After being brought back to ambient pressure, they were seeded on humid soil in a plant pot. Many of these vegetable seeds began to germinate within 6 days after seeded.

  5. Germination of vegetable seeds exposed to very high pressure

    Science.gov (United States)

    Mori, Y.; Yokota, S.; Ono, F.

    2012-07-01

    Effects of high hydrostatic pressure were investigated on vegetable seeds in the GPa range to examine the potentialities of breed improvement by high-pressure processing. Specimens of several seeds of broccoli (Brassica oleracea var. italica), Turnip leaf (Brassica rapa var. perviridis) and Potherb Mustard (Brassica rapa var. nipposinica) were put in a teflon capsule with liquid high pressure medium, fluorinate, and inserted into a pyrophillite cube. By using a cubic anvil press a hydrostatic pressure of 5.5 GP a was applied to these seeds for 15 minutes. After being brought back to ambient pressure, they were seeded on humid soil in a plant pot. Many of these vegetable seeds began to germinate within 6 days after seeded.

  6. Glassy selenium at high pressure: Le Chatelier's principle still works

    Science.gov (United States)

    Brazhkin, V. V.; Tsiok, O. B.

    2017-10-01

    Selenium is the only easily vitrified elementary substance. Numerous experimental studies of glassy Se (g -Se) at high pressures show a large spread in the data on the compressibility and electrical resistivity of g -Se. Furthermore, H. Liu et al. [Proc. Natl. Acad. Sci. USA 105, 13229 (2008), 10.1073/pnas.0806857105] have arrived at the surprising conclusion that the volume of glass increases during pressure-induced crystallization. We have performed high-precision measurements of the specific volume and electrical resistivity of glassy selenium (g -Se) at high hydrostatic pressures up to 9 GPa. The measured bulk modulus at normal pressure is B =(9.0 5 ±0.15 ) GPa and its pressure derivative is BP'=6.4 ±0.2 . In the pressure range P <3 GPa, glassy selenium has an anomalously large negative second derivative of the bulk modulus. The electrical resistivity of g -Se decreases almost exponentially with increasing pressure and reaches 20 Ω cm at a pressure of 8.75 GPa. The inelastic behavior and weak relaxation of the volume for g -Se begin at pressures above 3.5 GPa; the volume and logarithm of the electrical resistivity relax significantly (logarithmically with the time) at pressures above 8 GPa. Bulk measurements certainly indicate that the volume of g -Se glass in the crystallization pressure range is larger than the volumes of both appearing crystalline phases (by 2% and 4%). Therefore, the "volume expansion phenomenon" suggested in [H. Liu et al., Proc. Natl. Acad. Sci. USA 105, 13229 (2008), 10.1073/pnas.0806857105] is not observed, and the pressure-induced crystallization of glassy selenium is consistent with the laws of thermodynamics.

  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. High Pressure Apparatus for Angle Dispersive Neutron Diffraction

    OpenAIRE

    Kazuo, Kamigaki; Takejiro, Kaneko; Shunya, Abe; Masayoshi, Ohashi

    1983-01-01

    A piston-cylinder type high pressure apparatus was designed for the angle dispersive neutron diffraction. A Ti-53wt% Zr alloy was used for the cylinder. The performance was tested by observing the structural transformation under pressure in RbBr from an NaCl-type to a CsCl-type.

  9. High-pressure and temperature investigations of energetic materials

    Science.gov (United States)

    Gump, J. C.

    2014-05-01

    Static high-pressure measurements are extremely useful for obtaining thermodynamic and phase stability information from a wide variety of materials. However, studying energetic materials can be challenging when extracting information from static high-pressure measurements. Energetic materials are traditionally C, H, N, O compounds with low crystalline symmetry, producing weak signal in commonly performed x-ray diffraction measurements. The small sample volume available in a static high-pressure cell exacerbates this issue. Additionally, typical hydrostatic compression media, such as methanol/ethanol, may react with many energetic materials. However, characterization of their thermodynamic parameters and phase stability is critical to understanding explosive performance and sensitivity. Crystalline properties, such as bulk modulus and thermal expansion, are necessary to accurately predict the behaviour of shocked solids using hydrodynamic codes. In order to obtain these values, equations of state of various energetic materials were investigated using synchrotron angle-dispersive x-ray diffraction experiments at static high-pressure and temperature. Intense synchrotron radiation overcomes the weak x-ray scattering of energetic materials in a pressure cell. The samples were hydrostatically compressed using a non-reactive hydrostatic medium and heated using a heated diamond anvil cell. Pressure - volume data for the materials were fit to the Birch-Murnaghan and Vinet formalisms to obtain bulk modulus and its first pressure derivative. Temperature - volume data at ambient pressure were fit to obtain the volume thermal expansion coefficient. Data from several energetic materials will be presented and compared.

  10. High hydrostatic pressure extraction of phenolic compounds from ...

    African Journals Online (AJOL)

    High hydrostatic pressure processing (HHPP) is a food processing method, in which food is subjected to the elevated pressure which is mostly between 100 to 800 MPa. HHPP is seen not only in food engineering, but also have other application areas, such as extraction of active ingredients from natural biomaterials.

  11. Investigation of Methacrylic Acid at High Pressure Using Neutron Diffraction

    DEFF Research Database (Denmark)

    Marshall, William G.; Urquhart, Andrew; Oswald, Iain D. H.

    2015-01-01

    This article shows that pressure can be a low-intensity route to the synthesis of polymethacrylic acid. The exploration of perdeuterated methacrylic acid at high pressure using neutron diffraction reveals that methacrylic acid exhibits two polymorphic phase transformations at relatively low...

  12. Sound in He II at high and low pressures

    International Nuclear Information System (INIS)

    Adamenko, I.N.; Tsyganok, V.I.

    1984-01-01

    The sound absorption coefficient at high pressures and the roton-induced renormalization of the first sound velocity are calculated using the expression for a mass operator, which was earlier derived by the authors. It is shown that the kinetic theory of sound propagation in He 2 changes essentially with the pressure rise. The calculation is compared with the available experimental results

  13. Impact of osmotic pressure and gelling in the generation of highly stable single core water-in-oil-in-water (W/O/W) nano multiple emulsions of aspirin assisted by two-stage ultrasonic cavitational emulsification.

    Science.gov (United States)

    Tang, Siah Ying; Sivakumar, Manickam; Nashiru, Billa

    2013-02-01

    The present investigation focuses in investigating the effect of osmotic pressure, gelling on the mean droplet diameter, polydispersity index, droplet size stability of the developed novel Aspirin containing water-in-oil-in-water (W/O/W) nano multiple emulsion. The aspirin-loaded nano multiple emulsion formulation was successfully generated using two-stage ultrasonic cavitational emulsification which had been reported in author's previous study. The osmotic behavior of ultrasonically prepared nano multiple emulsions were also examined with different glucose concentrations both in the inner and outer aqueous phases. In addition, introducing gelatin into the formulation also observed to play an important role in preventing the interdroplet coalescence via the formation of interfacial rigid film. Detailed studies were also made on the possible mechanisms of water migration under osmotic gradient which primarily caused by the permeation of glucose. Besides, the experimental results have shown that the interfacial tension between the two immiscible phases decreases with varying the composition of organic phase. Although the W/O/W emulsion prepared with the inner/outer glucose weight ratio of 1-0.5% (w/w) showed an excellent droplet stability, the formulation containing 0.5% (w/w) glucose in the inner aqueous phase appeared to be the most stable with minimum change in the mean droplet size upon one-week storage period. Based on the optimization, nano multiple emulsion droplets with the mean droplet diameter of around 400 nm were produced using 1.25% (w/w) Span 80 and 0.5% Cremophore EL. Overall, our investigation makes a pathway in proving that the use of ultrasound cavitation is an efficient yet promising approach in the generation of stable and uniform nano multiple emulsions and could be used in the encapsulation of various active pharmaceutical ingredients in the near future. Copyright © 2012 Elsevier B.V. All rights reserved.

  14. Safety analysis of high pressure gasous fuel container punctures

    Energy Technology Data Exchange (ETDEWEB)

    Swain, M.R. [Univ. of Miami, Coral Gables, FL (United States)

    1995-09-01

    The following report is divided into two sections. The first section describes the results of ignitability tests of high pressure hydrogen and natural gas leaks. The volume of ignitable gases formed by leaking hydrogen or natural gas were measured. Leaking high pressure hydrogen produced a cone of ignitable gases with 28{degrees} included angle. Leaking high pressure methane produced a cone of ignitable gases with 20{degrees} included angle. Ignition of hydrogen produced larger overpressures than did natural gas. The largest overpressures produced by hydrogen were the same as overpressures produced by inflating a 11 inch child`s balloon until it burst.

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

    Centers for Disease Control (CDC) Podcasts

    2012-09-04

    Nearly one-third of American adults have high blood pressure, and more than half of them don’t have it under control. Simply seeing a doctor and taking medications isn’t enough for many people who have high blood pressure. A team-based approach by patients, health care systems, and health care providers is one of the best ways to treat uncontrolled high blood pressure.  Created: 9/4/2012 by Centers for Disease Control and Prevention (CDC).   Date Released: 9/4/2012.

  16. Safety supervision on high-pressure gas regulations

    International Nuclear Information System (INIS)

    Lee, Won Il

    1991-01-01

    The first part lists the regulation on safety supervision of high-pressure gas, enforcement ordinance on high-pressure gas safety supervision and enforcement regulations about high-pressure gas safety supervision. The second part indicates safety regulations on liquefied petroleum gas and business, enforcement ordinance of safety on liquefied petroleum gas and business, enforcement regulation of safety supervision over liquefied petroleum gas and business. The third part lists regulation on gas business, enforcement ordinance and enforcement regulations on gas business. Each part has theory and explanation for questions.

  17. Excessively High Vapor Pressure of Al-based Amorphous Alloys

    Directory of Open Access Journals (Sweden)

    Jae Im Jeong

    2015-10-01

    Full Text Available Aluminum-based amorphous alloys exhibited an abnormally high vapor pressure at their approximate glass transition temperatures. The vapor pressure was confirmed by the formation of Al nanocrystallites from condensation, which was attributed to weight loss of the amorphous alloys. The amount of weight loss varied with the amorphous alloy compositions and was inversely proportional to their glass-forming ability. The vapor pressure of the amorphous alloys around 573 K was close to the vapor pressure of crystalline Al near its melting temperature, 873 K. Our results strongly suggest the possibility of fabricating nanocrystallites or thin films by evaporation at low temperatures.

  18. Magnetic phase diagram of FeO at high pressure

    Science.gov (United States)

    Zhang, Peng; Cohen, R. E.; Haule, K.

    2017-05-01

    FeO is an insulator with anti-ferromagnetic (AFM) spin ordering at ambient pressure. At increased external pressure, the Néel temperature of FeO first increases at the pressure below 40 GPa. Experiments predict that the AFM ordering will collapse above 80 GPa, but the mechanism of the high pressure magnetic collapse is still unknown. Using the combination of density functional theory and dynamical mean-field theory (DFT+DMFT), the nature of the magnetic collapse of FeO is examined and its magnetic phase diagram up to 180 GPa is discussed.

  19. Effect of High Pressure and Heat on Bacterial Toxins

    Directory of Open Access Journals (Sweden)

    Dirk Margosch

    2005-01-01

    Full Text Available Even though the inactivation of microorganisms by high pressure treatment is a subject of intense investigations, the effect of high pressure on bacterial toxins has not been studied so far. In this study, the influence of combined pressure/temperature treatment (0.1 to 800 MPa and 5 to 121 °C on bacterial enterotoxins was determined. Therefore, heat-stable enterotoxin (STa of cholera toxin (CT from Vibrio cholerae, staphylococcal enterotoxins A-E, haemolysin BL (HBL from Bacillus cereus, and Escherichia coli (STa were subjected to different treatment schemes. Structural alterations were monitored in enzyme immunoassays (EIAs. Cytotoxicity of the pressure treated supernatant of toxigenic B. cereus DSM 4384 was investigated with Vero cells. High pressure of 200 to 800 MPa at 5 °C leads to a slight increase of the reactivity of the STa of E. coli. However, reactivity decreased at 800 MPa and 80 °C to (66±21 % after 30 min and to (44±0.3 % after 128 min. At ambient pressure no decrease in EIA reactivity could be observed after 128 min. Pressurization (0.1 to 800 MPa of heat stable monomeric staphylococcal toxins at 5 and 20 °C showed no effect. A combined heat (80 °C and pressure (0.1 to 800 MPa treatment lead to a decrease in the immuno-reactivity to 20 % of its maximum. For cholera toxin a significant loss in latex agglutination was observable only at 80 °C and 800 MPa for holding times higher than 20 min. Interestingly, the immuno-reactivity of B. cereus HBL toxin increased with the increase of pressure (182 % at 800 MPa, 30 °C, and high pressure showed only minor effects on cytotoxicity to Vero cells. Our results indicate that pressurization can increase inactivation observed by heat treatment, and combined treatments may be effective at lower temperatures and/or shorter incubation time.

  20. Prospective observational study of single- or multi-compartment pressure ulcer prevention cushions: PRESCAROH project.

    Science.gov (United States)

    Meaume, S; Marty, M; Colin, D

    2017-09-02

    In patients with reduced mobility, specialised pressure-relieving supports (mattresses, beds and cushions) are widely used to reduce or relieve the interface pressure between the skin and support surfaces to prevent incidence of pressure ulcers (PUs). The primary objective of these two observational studies was to assess the incidence of PUs in patients at high risk of PUs, seated in a wheelchair using a single- or multi-compartment air cushion. The level of patient satisfaction with the comfort and the views of the care team that used the air cushions were considered as secondary objectives. The PRESCAROH project was two prospective observational studies conducted in patients free of PUs at baseline and at high risk of PUs (Braden score ≤13 or ≤16 for people with spinal cord injury). Patients had to spend more than eight hours a day in a wheelchair and use either a single-compartment air cushion (patient without asymmetry of support) for the first study or a multi-compartment air cushion (patient with asymmetry of support) for the second study. The primary end point was the percentage of patients in whom a PU (sacrum and/or ischium) developed over a 35-day period. The analysis was performed on the full-analysis set (FAS) of patients included with at least a second assessment. We recruited 152 patients, 78 seated on a single-compartment air cushion (SiCAC group) and 74 on a multi-compartment air cushion (MuCAC group), in the two independent studies. All patients were included in the FAS (n=152). Most patients had spinal cord injuries. The average time spent sitting was 10.2 (standard deviation (SD): 2.3) hours a day in the SiCAC group and 9.1 (SD: 1.9) hours a day in the MuCAC group. In the SiCAC group, 6.4% (5/78) of patients dropped out of the study (one patient because of pulmonary infection and four patients for cushion installation problems). In the MuCAC group, 8.1% (6/74) of patients dropped out of the study (three patients because of adverse events not

  1. 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.

  2. Interactions of high hydrostatic pressure, pressurization temperature and pH on death and injury of pressure-resistant and pressure-sensitive strains of foodborne pathogens.

    Science.gov (United States)

    Alpa, H; Kalchayanand, N; Bozoglu, F; Ray, B

    2000-09-15

    The objective of this study is to determine the interactions between high hydrostatic pressure, pressurization temperature, time and pH during pressurization on death and injury of pressure-resistant and pressure-sensitive strains of four foodborne pathogens: Staphylococcus aureus 485 and 765, Listeria ,monocytogenes CA and OH2, Escherichia coli O157:H7 933 and 931, Salmonella enteritidis FDA and Salmonella typhimurium E21274. Among these strains S. aureus 485, L. monocytogenes CA, E. coli O157:H7 933 and S. enteritidis FDA were reported to be more pressure-resistant than the respective strain of the same species (Alpas et al., 1999). In general, viability loss of all pathogens was enhanced significantly as the level of pressure and temperature were increased (P pasteurization applications to liquid foods that have low pH. reserved.

  3. Synthetic chemistry with periodic mesostructures at high pressure.

    Science.gov (United States)

    Mandal, Manik; Landskron, Kai

    2013-11-19

    Over the last two decades, researchers have studied extensively the synthesis of mesostructured materials, which could be useful for drug delivery, catalytic cracking of petroleum, or reinforced plastics, among other applications. However, until very recently researchers used only temperature as a thermodynamic variable for synthesis, completely neglecting pressure. In this Account, we show how pressure can affect the synthetic chemistry of periodic mesoporous structures with desirable effects. In its simplest application, pressure can crystallize the pore walls of periodic mesoporous silicas, which are difficult to crystallize otherwise. The motivation for the synthesis of periodic mesoporous silica materials (with pore sizes from 2 to 50 nm) 20 years ago was to replace the microporous zeolites (which have pore sizes of amorphous nature of the mesoporous materials' channel walls. To address this problem, we developed the concept of "nanocasting at high pressure". Through this approach, we produced hitherto-unavailable, periodic mesostructured silicas with crystalline pore walls. In nanocasting, we compress a periodic mesostructured composite (e.g. a periodic mesoporous silica with carbon-filled pores) and subsequently heat it to induce the selective crystallization of one of the two phases. We attain the necessary high pressure for synthesis using piston-cylinder and multianvil apparatuses. Using periodic mesostructured silica/carbon nanocomposites as starting material, we have produced periodic mesoporous coesite and periodic mesoporous quartz. The quartz material is highly stable under harsh hydrothermal conditions (800°C in pure steam), verifying that crystallinity in the channel walls of periodic mesoporous silicas increases their hydrothermal stability. Even without including the carbon phase in the silica pores, we could obtain mesoporous coesite materials. We found similar behavior for periodic mesoporous carbons, which convert into transparent, mesoporous

  4. High pressure in semiconductor physics II

    CERN Document Server

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

    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...

  5. 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.

  6. Decay properties of high-lying single-particles modes

    Energy Technology Data Exchange (ETDEWEB)

    Beaumel, D. [Institut de Physique Nucleaire, 91 - Orsay (France); Fortier, S. [Institut de Physique Nucleaire, 91 - Orsay (France); Gales, S. [Institut de Physique Nucleaire, 91 - Orsay (France); Guillot, J. [Institut de Physique Nucleaire, 91 - Orsay (France); Langevin-Joliot, H. [Institut de Physique Nucleaire, 91 - Orsay (France); Laurent, H. [Institut de Physique Nucleaire, 91 -Orsay (France); Maison, J.M. [Institut de Physique Nucleaire, 91 - Orsay (France); Vernotte, J. [Institut de Physique Nucleaire, 91 - Orsay (France); Bordewijck, J. [Kernfysisch Versneller Instituut, 9747 Groningen (Netherlands); Brandenburg, S. [Kernfysisch Versneller Instituut, 9747 Groningen (Netherlands); Krasznahorkay, A. [Kernfysisch Versneller Instituut, 9747 Groningen (Netherlands); Crawley, G.M. [NSCL, Michigan State University, East Lansing, MI 48824 (United States); Massolo, C.P. [Universitad Nacional de La Plata, 1900 La Plata (Argentina); Renteria, M. [Universitad Nacional de La Plata, 1900 La Plata (Argentina); Khendriche, A. [University of Tizi-Ouzou, Tizi-Ouzou (Algeria)

    1996-03-18

    The neutron decay of high-lying single-particle states in {sup 64}Ni, {sup 90}Zr, {sup 120}Sn and {sup 208}Pb excited by means of the ({alpha},{sup 3}He) reaction has been investigated at 120 MeV incident energy using the multidetector EDEN. The characteristics of this reaction are studied using inclusive spectra and angular correlation analysis. The structure located between 11 and 15 MeV in {sup 91}Zr, and between 8 and 12 MeV excitation energy in {sup 209}Pb display large departures from a pure statistical decay. The corresponding non-statistical branching ratios are compared with the results of two theoretical calculations. (orig.).

  7. Elastic properties of Fe-bearing wadsleyite at high pressures

    Science.gov (United States)

    Mao, Z.; Jacobsen, S. D.; Jiang, F.; Smyth, J. R.; Holl, C. M.; Frost, D. J.; Duffy, T.

    2009-12-01

    The elastic properties of wadsleyite, thought to be the dominant phase from 410 to 520-km depth in the mantle, are essential to interpret the seismic images and profiles in the transition zone. Our previous experimental measurements showed that elasticity of Mg2SiO4 wadsleyite can be significantly reduced by hydration at high pressures (e.g. Mao et al., 2008a,b). These results provide the first constraints on the effect of hydration on the high-pressure sound velocities of wadsleyite, and are significantly important for identifying the potential hydrogen rich region in the Earth’s transition zone. Since mantle wadsleyite contains ~10 mol.% Fe, it is more important to investigate the combined effect of Fe and hydration on the elastic properties of wadsleyite. Here, we measured the single-crystal elasticity of wadsleyite with 1.0 wt.% H2O, Mg1.73Fe0.19SiO4H0.16, up to 12 GPa using Brillouin scattering. At ambient conditions, the aggregate bulk modulus, KS0, and shear modulus, G0, are 158.4(5) GPa and 99.2(3) GPa, respectively. Including the results of current and previous studies, we find that the elasticity of wadsleyite decreases linearly with Fe and H2O content according to relations (in GPa): KS0 = 171(3)-13.0(8)CH2O, G0 = 112(2)-8.8(3)CH2O-40(10)XFe, where CH2O is the concentration of hydrogen expressed as weight percent H2O, and XFe is the Fe molar fraction (XFe = Fe/(Mg+Fe)). Further high-pressure measurements showed that the presence of 1 wt.% H2O in Fe-bearing wadsleyite increases the pressure derivative of the shear modulus from 1.5(1) to 1.9(1). But Fe-bearing wadsleyite with this amount of H2O might have a similar pressure derivative of the bulk modulus (4.8(1)) similar to the corresponding anhydrous phase. Using our results, we computed the sound velocities of wadsleyite with 1 wt.% H2O up to 12 GPa at 300 K. Compared to Fe-bearing anhydrous wadsleyite, 1 wt.% H2O causes a 1.5(4)% reduction in the compressional velocity at 12 GPa, and a 1

  8. Tolerance of budding yeast Saccharomyces cerevisiae to ultra high pressure

    Science.gov (United States)

    Shibata, M.; Torigoe, M.; Matsumoto, Y.; Yamamoto, M.; Takizawa, N.; Hada, Y.; Mori, Y.; Takarabe, K.; Ono, F.

    2014-05-01

    Our studies on the tolerance of plants and animals against very high pressure of several GPa have been extended to a smaller sized fungus, the budding yeast Saccharomyces cerevisiae. Several pieces of budding yeast (dry yeast) were sealed in a small teflon capsule with a liquid pressure medium fluorinate, and exposed to 7.5 GPa by using a cubic anvil press. The pressure was kept constant for various duration of time from 2 to 24 h. After the pressure was released, the specimens were brought out from the teflon capsule, and they were cultivated on a potato dextrose agar. It was found that the budding yeast exposed to 7.5 GPa for up to 6 h showed multiplication. However, those exposed to 7.5 GPa for longer than 12 h were found dead. The high pressure tolerance of budding yeast is a little weaker than that of tardigrades.

  9. The high pressure gas Cerenkov counter at the Omega Facility.

    CERN Multimedia

    1975-01-01

    The high-pressure gas Cerenkov was used to measure reactions as pion (or kaon)- hydrogen --> forward proton - X. It was built by the Ecole Polytechnique (Palaiseu). Here Peter Sonderegger and Patrick Fleury,

  10. High-pressure gas chamber for neutron diffraction studies

    International Nuclear Information System (INIS)

    Stepanov, G. N.; Telepnev, A. S.; Simkin, V. G.

    2007-01-01

    The construction of a chamber designed for neutron diffraction studies of the structure of solids under high gas pressures up to 0.5 GPa is described. This chamber is a modification of the chamber published earlier

  11. Bio-Hemostat-Acute Treatment Modality for High Pressure Hemorrhage

    National Research Council Canada - National Science Library

    Carr, Marcus

    2002-01-01

    Bleeding from an artery is difficult to control due to the high pressures found in the arterial system Hemorrhage is especially problematic in penetrating wounds where the bleeding source may not be...

  12. Novel High Pressure Pump-on-a-Chip Technology Project

    Data.gov (United States)

    National Aeronautics and Space Administration — HJ Science & Technology, Inc proposes to develop a novel high pressure "pump-on-a-chip" and "valve-on-a-chip" microfluidic technology for NASA planetary science...

  13. Beam steering effects in turbulent high pressure flames

    Energy Technology Data Exchange (ETDEWEB)

    Hemmerling, B.; Kaeppeli, B. [Paul Scherrer Inst. (PSI), Villigen (Switzerland)

    1997-06-01

    The propagation of a laser beam through a flame is influenced by variations of the optical density. Especially in turbulent high pressure flames this may seriously limit the use of laser diagnostic methods. (author) 1 fig., 2 refs.

  14. Use of genetic algorithms for high hydrostatic pressure inactivation ...

    African Journals Online (AJOL)

    ) for high hydrostatic pressure (HHP) inactivation of Bacillus cereus spores, Bacillus subtilis spores and cells, Staphylococcus aureus and Listeria monocytogenes, all in milk buffer, were used to demonstrate the utility of genetic algorithms ...

  15. Exhumation of (ultra-high-pressure terranes: concepts and mechanisms

    Directory of Open Access Journals (Sweden)

    C. J. Warren

    2013-02-01

    Full Text Available The formation and exhumation of high and ultra-high-pressure, (UHP, rocks of crustal origin appears to be ubiquitous during Phanerozoic plate subduction and continental collision events. Exhumation of (UHP material has been shown in some orogens to have occurred only once, during a single short-lived event; in other cases exhumation appears to have occurred multiple discrete times or during a single, long-lived, protracted event. It is becoming increasingly clear that no single exhumation mechanism dominates in any particular tectonic environment, and the mechanism may change in time and space within the same subduction zone. Subduction zone style and internal force balance change in both time and space, responding to changes in width, steepness, composition of subducting material and velocity of subduction. In order for continental crust, which is relatively buoyant compared to the mantle even when metamorphosed to (UHP assemblages, to be subducted to (UHP conditions, it must remain attached to a stronger and denser substrate. Buoyancy and external tectonic forces drive exhumation, although the changing spatial and temporal dominance of different driving forces still remains unclear. Exhumation may involve whole-scale detachment of the terrane from the subducting slab followed by exhumation within a subduction channel (perhaps during continued subduction or a reversal in motion of the entire plate (eduction following the removal of a lower part of the subducting slab. Weakening mechanisms that may be responsible for the detachment of deeply subducted crust from its stronger, denser substrate include strain weakening, hydration, melting, grain size reduction and the development of foliation. These may act locally to form narrow high-strain shear zones separating stronger, less-strained crust or may act on the bulk of the subducted material, allowing whole-scale flow. Metamorphic reactions, metastability and the composition of the subducted crust

  16. The compact mirrors with high pressure plasmas

    International Nuclear Information System (INIS)

    Anikeev, A.V.; Bagryansky, P.A.; Ivanov, A.A.; Lizunov, A.A.; Murakhtin, S.V.; Prikhodko, V.V.; Collatz, S.; Noack, K.

    2004-01-01

    The gas dynamic trap (GDP) experimental facility at the Budker Institute Novosibirsk is a long axial-symmetric mirror system with a high mirror ratio variable in the range of 12.5 - 100 for the confinement of a two-component plasma. One component is a collisional plasma with ion and electron temperatures up to 100 eV and density up to 10 14 cm -3 . The second component is the population of high-energetic fast ions with energies of 2-18 keV and a density up to 10 13 cm -3 which is produced by neutral beam injection (NBI). GDP is currently undergoing an upgrade whose first stage is the achievement of the synthesized hot ion plasmoid experiment (SHIP). This experiment aims at the investigation of plasmas and at the knowledge of plasma parameters that have never been achieved before in magnetic mirrors. The paper presents the physical concept of the SHIP experiment, the results of numerical pre-calculations and draws conclusions regarding possible scenarios of experiments. The simulation of a maximal NBI power regime with hydrogen injection gave a fast ion density of 1.2*10 14 cm -3 with a mean energy of 14 keV. The calculation of the deuterium injection regime with 2 MW NBI power gave a maximal fast ion density of 1.9*10 14 cm -3 with a beam energy of 9 keV. The calculation of an experimental scenario with reduced magnetic field resulted in a maximal β-value of 62%, so this regime is recommended for the study of high-β effects in plasmas confined in axial-symmetric mirrors

  17. Intrinsic pressure response of a single mode cyclo olefin polymer fiber bragg grating

    DEFF Research Database (Denmark)

    Pedersen, Jens Kristian Mølgaard; Woyessa, Getinet; Nielsen, Kristian

    2016-01-01

    The intrinsic pressure response of a Fibre Bragg Grating (FBG) inscribed in a single-mode cyclo olefin polymer (COP) microstructured polymer optical fibre (mPOF) in the range 0-200 bar is investigated for the first time. In order to efficiently suppress the effects from changes in temperature...

  18. Resistive internal kink modes in a tokamak with high-pressure plasma

    International Nuclear Information System (INIS)

    Kuvshinov, B.N.; Mikhajlovskij, A.B.; Tatarinov, E.G.

    1988-01-01

    Theory of resistive internal kink modes in a tokamak with high-pressure plasma is developed. Equation for Fourie-image of disturbed displacment in a resistive layer ie derived with regard to effects of the fourth order by plasma pressure within the framework of single-liquid approach. In its structure this equation coincides with a similar equation for resistive balloon modes and has an exact solution expressed by degenerated hypergeometric function. A general dispersion equation for resistive kink modes is derived with regard to the effects indicated. It is shown that plasma pressure finiteness leads to the reduction of reconnection and tyring-mode increments

  19. New Outlook on the High-Pressure Behavior of Pentaerythritol Tetranitrate

    National Research Council Canada - National Science Library

    Ciezak, Jennifer A; Jenkins, Timothy A

    2007-01-01

    To gain insight into the high-pressure behavior of pentaerythritol tetranitrate (C(CH2ONO2)4), single crystal Raman spectroscopy results were obtained for hydrostatic/quasi-hydrostatic and non-hydrostatic compression in a diamond anvil cell...

  20. Advanced High-Temperature, High-Pressure Transport Reactor Gasification

    Energy Technology Data Exchange (ETDEWEB)

    Michael L. Swanson

    2005-08-30

    50 hours of gasification on a petroleum coke from the Hunt Oil Refinery and an additional 73 hours of operation on a high-ash coal from India. Data from these tests indicate that while acceptable fuel gas heating value was achieved with these fuels, the transport gasifier performs better on the lower-rank feedstocks because of their higher char reactivity. Comparable carbon conversions have been achieved at similar oxygen/coal ratios for both air-blown and oxygen-blown operation for each fuel; however, carbon conversion was lower for the less reactive feedstocks. While separation of fines from the feed coals is not needed with this technology, some testing has suggested that feedstocks with higher levels of fines have resulted in reduced carbon conversion, presumably due to the inability of the finer carbon particles to be captured by the cyclones. These data show that these low-rank feedstocks provided similar fuel gas heating values; however, even among the high-reactivity low-rank coals, the carbon conversion did appear to be lower for the fuels (brown coal in particular) that contained a significant amount of fines. The fuel gas under oxygen-blown operation has been higher in hydrogen and carbon dioxide concentration since the higher steam injection rate promotes the water-gas shift reaction to produce more CO{sub 2} and H{sub 2} at the expense of the CO and water vapor. However, the high water and CO{sub 2} partial pressures have also significantly reduced the reaction of (Abstract truncated)

  1. Model of Structural Fragmentation Induced by High Pressure Torsion

    Czech Academy of Sciences Publication Activity Database

    Kratochvíl, J.; Kružík, Martin; Sedláček, R.

    2010-01-01

    Roč. 25, č. 1 (2010), s. 88-98 ISSN 1606-5131 Institutional research plan: CEZ:AV0Z10750506 Keywords : High-pressure torsion * intergranular glide * homogeneous deformation mode Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 0.649, year: 2010 http://library.utia.cas.cz/separaty/2010/MTR/kruzik-model of structural fragmentation induced by high pressure torsion.pdf

  2. Thermal neutron scattering studies of condensed matter under high pressures

    International Nuclear Information System (INIS)

    Carlile, C.J.; Salter, D.C.

    1978-01-01

    Although temperature has been used as a thermodynamic variable for samples in thermal neutron scattering experiments since the inception of the neutron technique, it is only in the last decade that high pressures have been utilised for this purpose. In the paper the problems particular to this field of work are outlined and a review is made of the types of high-pressure cells used and the scientific results obtained from the experiments. 103 references. (author)

  3. Signal processing in urodynamics: towards high definition urethral pressure profilometry.

    Science.gov (United States)

    Klünder, Mario; Sawodny, Oliver; Amend, Bastian; Ederer, Michael; Kelp, Alexandra; Sievert, Karl-Dietrich; Stenzl, Arnulf; Feuer, Ronny

    2016-03-22

    Urethral pressure profilometry (UPP) is used in the diagnosis of stress urinary incontinence (SUI) which is a significant medical, social, and economic problem. Low spatial pressure resolution, common occurrence of artifacts, and uncertainties in data location limit the diagnostic value of UPP. To overcome these limitations, high definition urethral pressure profilometry (HD-UPP) combining enhanced UPP hardware and signal processing algorithms has been developed. In this work, we present the different signal processing steps in HD-UPP and show experimental results from female minipigs. We use a special microtip catheter with high angular pressure resolution and an integrated inclination sensor. Signals from the catheter are filtered and time-correlated artifacts removed. A signal reconstruction algorithm processes pressure data into a detailed pressure image on the urethra's inside. Finally, the pressure distribution on the urethra's outside is calculated through deconvolution. A mathematical model of the urethra is contained in a point-spread-function (PSF) which is identified depending on geometric and material properties of the urethra. We additionally investigate the PSF's frequency response to determine the relevant frequency band for pressure information on the urinary sphincter. Experimental pressure data are spatially located and processed into high resolution pressure images. Artifacts are successfully removed from data without blurring other details. The pressure distribution on the urethra's outside is reconstructed and compared to the one on the inside. Finally, the pressure images are mapped onto the urethral geometry calculated from inclination and position data to provide an integrated image of pressure distribution, anatomical shape, and location. With its advanced sensing capabilities, the novel microtip catheter collects an unprecedented amount of urethral pressure data. Through sequential signal processing steps, physicians are provided with

  4. Ionic transport properties in AgCl under high pressures

    Science.gov (United States)

    Wang, Jia; Zhang, Guozhao; Liu, Hao; Wang, Qinglin; Shen, Wenshu; Yan, Yalan; Liu, Cailong; Han, Yonghao; Gao, Chunxiao

    2017-07-01

    Ionic transport behaviors of silver chloride (AgCl) have been revealed with impedance spectra measurement under high pressures up to 20.4 GPa. AgCl always presented ionic conducting under experimental pressures, but electronic conduction can coexist with ionic conduction within the pressure range from 6.7 to 9.3 GPa. The ionic conductivity of AgCl decreases by three orders of magnitude under compression, indicating that Ag+ ion migrations are suppressed by high pressure. A parameter, fW, was defined as the starting frequency at which Ag+ ions begin to show obvious long-distance diffusion in AgCl. fW showed a similar trend with the ionic conductivity under high pressures, indicating that the speed of Ag+ ion diffusion slows down as the pressure increases. Unlike AgI, Ag+ ion diffusion in AgCl is controlled by the indirect-interstitial mechanism. Due to stronger ionic bonds and larger lattice deformation, Ag+ ion diffusion in the rigid Cl- lattice is more difficult than in the I- lattice under high pressures.

  5. High pressure and multiferroics materials: a happy marriage

    Directory of Open Access Journals (Sweden)

    Edmondo Gilioli

    2014-11-01

    Full Text Available The community of material scientists is strongly committed to the research area of multiferroic materials, both for the understanding of the complex mechanisms supporting the multiferroism and for the fabrication of new compounds, potentially suitable for technological applications. The use of high pressure is a powerful tool in synthesizing new multiferroic, in particular magneto-electric phases, where the pressure stabilization of otherwise unstable perovskite-based structural distortions may lead to promising novel metastable compounds. The in situ investigation of the high-pressure behavior of multiferroic materials has provided insight into the complex interplay between magnetic and electronic properties and the coupling to structural instabilities.

  6. High-pressure test loop design and application

    International Nuclear Information System (INIS)

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

    1980-07-01

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

  7. High-pressure-low-temperature x-ray power diffractometer.

    Science.gov (United States)

    Syassen, K; Holzapfel, W B

    1978-08-01

    A high-pressure technique for x-ray diffraction studies at low temperatures is described. The system consists of a Bridgman anvil type high-pressure device with either tungsten carbide or boron carbide anvils, a liquid He cryostat, and x-ray diffractometer operating in Debye-Scherrer geometry. The newly developed boron carbide anvil cell is capable of containing a liquid pressure transmitting medium. The precision of the lattice parameter determination is discussed and the effect of nonisostatic stress components on the diffraction pattern is examined.

  8. Characterization of high-pressure RTM processes for manufacturing of high performance composites

    OpenAIRE

    Chaudhari, R.; Karcher, M.; Elsner, P.; Henning, F.

    2012-01-01

    The current paper addresses new variants of the RTM process namely High Pressure-Injection Resin Transfer Molding (HP-IRTM) and High Pressure - Compression Resin Transfer Molding (HP-CRTM) for manufacturing of continuous fiber reinforced composites with high fiber volume content. Both these process utilize High Pressure RTM equipment for precise dosing and mixing of highly reactive epoxy resin and amine hardener with relatively high throughput rates. The objective of the proposed study was to...

  9. Advances and synergy of high pressure sciences at synchrotron sources

    International Nuclear Information System (INIS)

    Liu, H.; Ehm, L.; Duffy, T.; Crichton, W.; Aoki, K.

    2009-01-01

    Introductory overview to the special issue papers on high-pressure sciences and synchrotron radiation. High-pressure research in geosciences, materials science and condensed matter physics at synchrotron sources is experiencing growth and development through synergistic efforts around the world. A series of high-pressure science workshops were organized in 2008 to highlight these developments. One of these workshops, on 'Advances in high-pressure science using synchrotron X-rays', was held at the National Synchrotron Light Source (NSLS), Brookhaven National Laboratory, USA, on 4 October 2008. This workshop was organized in honour of Drs Jingzhu Hu and Quanzhong Guo in celebration of their retirement after up to 18 years of dedicated service to the high-pressure community as beamline scientists at X17 of NSLS. Following this celebration of the often unheralded role of the beamline scientist, a special issue of the Journal of Synchrotron Radiation on Advances and Synergy of High-Pressure Sciences at Synchrotron Sources was proposed, and we were pleased to invite contributions from colleagues who participated in the workshop as well as others who are making similar efforts at synchrotron sources worldwide.

  10. Association between parity and breastfeeding with maternal high blood pressure.

    Science.gov (United States)

    Lupton, Samantha J; Chiu, Christine L; Lujic, Sanja; Hennessy, Annemarie; Lind, Joanne M

    2013-06-01

    The objective of this study was to determine how parity and breastfeeding were associated with maternal high blood pressure, and how age modifies this association. Baseline data for 74,785 women were sourced from the 45 and Up Study, Australia. These women were 45 years of age or older, had an intact uterus, and had not been diagnosed with high blood pressure before pregnancy. Odds ratios (ORs) and 99% confidence intervals (CIs) for the association between giving birth, breastfeeding, lifetime breastfeeding duration, and average breastfeeding per child with high blood pressure were estimated using logistic regression. The combination of parity and breastfeeding was associated with lower odds of having high blood pressure (adjusted OR, 0.89; 99% CI, 0.82-0.97; P high blood pressure when compared with parous women who never breastfed. The odds were lower with longer breastfeeding durations and were no longer significant in the majority of women over the age of 64 years. Women should be encouraged to breastfeed for as long as possible and a woman's breastfeeding history should be taken into account when assessing her likelihood of high blood pressure in later life. Copyright © 2013 Mosby, Inc. All rights reserved.

  11. High blood pressure in older subjects with cognitive impairment.

    Science.gov (United States)

    Mossello, Enrico; Simoni, David

    2016-06-22

    High blood pressure and cognitive impairment often coexist in old age, but their pathophysiological association is complex. Several longitudinal studies have shown that high blood pressure at midlife is a risk factor for cognitive impairment and dementia, although this association is much less clear in old age. The effect of blood pressure lowering in reducing the risk of dementia is only borderline significant in clinical trials of older subjects, partly due to the insufficient follow-up time. Conversely, dementia onset is associated with a decrease of blood pressure values, probably secondary to neurodegeneration. Prognostic effect of blood pressure values in cognitively impaired older subjects is still unclear, with aggressive blood pressure lowering being potentially harmful in this patients category. Brief cognitive screening, coupled with simple motor assessment, are warranted to identify frail older subjects who need a more cautious approach to antihypertensive treatment. Values obtained with ambulatory blood pressure monitoring seem more useful than clinical ones to predict the outcome of cognitively impaired older subjects. Future studies should identify the most appropriate blood pressure targets in older subjects with cognitive impairment.

  12. Aqueous Geochemistry at High Pressures and High Temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Bass, Jay D. [Univ. of Illinois, Urbana-Champaign, IL (United States)

    2015-05-21

    This project is aimed at experimental characterization of the sound velocities, equations of state (EOS), and derived physical and chemical properties of aqueous solutions and carbon dioxide at extreme pressure and temperature conditions relevant to processes occurring in the interior of the Earth. Chemical transport, phase changes (including melting), fluid-solid reactions, and formation of magmatic liquids at convergent plat boundaries are a key motivation for this project. Research in this area has long been limited by the extreme experimental challenges and lack of data under the appropriate pressure-temperature (P-T) conditions. The vast majority of studies of aqueous geochemistry relevant to terrestrial problems of fluid-rock interactions have been conducted at 0.3 GPa or less, and the widely used Helgeson-Kirkham-Flowers equation of state for aqueous species is applicable only at ~ < 0.5 GPa. These limits are unfortunate because fluid flow and reactions plays a central role in many deeper environments. Recent efforts including our own, have resulted in new experimental techniques that now make it possible to investigate properties of homogeneous and heterogeneous equilibria involving aqueous species and minerals over a much broader range of pressure and temperature appropriate for deep crustal and upper mantle processes involving water-rich fluids. We carried out 1) Brillouin scattering measurements of the equations of state and molar volume of water and carbon dioxide to over 10 GPa and 870K using precise resistance heating of samples under pressure in the diamond anvil cell, and 2) the phase diagrams of the water and CO2, and 3) Exploring new experimental approaches, including CO2 laser heating of samples in a diamond cell, to measurements of sound velocities, EOS, and phase relations by Brillouin scattering to far greater pressures and temperatures.

  13. High pressure-sensitive gene expression in Lactobacillus sanfranciscensis

    Directory of Open Access Journals (Sweden)

    R.F. Vogel

    2005-08-01

    Full Text Available Lactobacillus sanfranciscensis is a Gram-positive lactic acid bacterium used in food biotechnology. It is necessary to investigate many aspects of a model organism to elucidate mechanisms of stress response, to facilitate preparation, application and performance in food fermentation, to understand mechanisms of inactivation, and to identify novel tools for high pressure biotechnology. To investigate the mechanisms of the complex bacterial response to high pressure we have analyzed changes in the proteome and transcriptome by 2-D electrophoresis, and by microarrays and real time PCR, respectively. More than 16 proteins were found to be differentially expressed upon high pressure stress and were compared to those sensitive to other stresses. Except for one apparently high pressure-specific stress protein, no pressure-specific stress proteins were found, and the proteome response to pressure was found to differ from that induced by other stresses. Selected pressure-sensitive proteins were partially sequenced and their genes were identified by reverse genetics. In a transcriptome analysis of a redundancy cleared shot gun library, about 7% of the genes investigated were found to be affected. Most of them appeared to be up-regulated 2- to 4-fold and these results were confirmed by real time PCR. Gene induction was shown for some genes up-regulated at the proteome level (clpL/groEL/rbsK, while the response of others to high hydrostatic pressure at the transcriptome level seemed to differ from that observed at the proteome level. The up-regulation of selected genes supports the view that the cell tries to compensate for pressure-induced impairment of translation and membrane transport.

  14. Superstrong micro-grained polycrystalline diamond compact through work hardening under high pressure

    Science.gov (United States)

    Liu, Jin; Zhan, Guodong; Wang, Qiang; Yan, Xiaozhi; Liu, Fangming; Wang, Pei; Lei, Li; Peng, Fang; Kou, Zili; He, Duanwei

    2018-02-01

    We report an approach to strengthen micro-grained polycrystalline diamond (MPD) compact through work hardening under high pressure and high temperature, in which both hardness and fracture toughness are simultaneously boosted. Micro-sized diamond powders are treated without any additives under a high pressure of 14 GPa and temperatures ranging from 1000 °C to 2000 °C. It was found that the high pressure and high temperature environments could constrain the brittle feature and cause a severe plastic deformation of starting diamond grains to form a mutual bonded diamond network. The relative density is increased with temperature to nearly fully dense at 1600 °C. The Vickers hardness of the well-prepared MPD bulks at 14 GPa and 1900 °C reaches the top limit of the single crystal diamond of 120 GPa, and the near-metallic fracture toughness of the sample is as high as 18.7 MPa m1/2.

  15. Shape transition of unstrained flattest single-walled carbon nanotubes under pressure

    Energy Technology Data Exchange (ETDEWEB)

    Mu, Weihua, E-mail: whmu@mit.edu, E-mail: muwh@itp.ac.cn [Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States); State Key Laboratory of Theoretical Physics, Institute of Theoretical Physics, The Chinese Academy of Sciences, P. O. Box 2735 Beijing 100190 (China); Kavli Institute for Theoretical Physics China, The Chinese Academy of Sciences, P. O. Box 2735 Beijing 100190 (China); Cao, Jianshu, E-mail: jianshu@mit.edu [Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States); Singapore-MIT Alliance for Research and Technology (SMART), Singapore 138602 (Singapore); Ou-Yang, Zhong-can [State Key Laboratory of Theoretical Physics, Institute of Theoretical Physics, The Chinese Academy of Sciences, P. O. Box 2735 Beijing 100190 (China); Kavli Institute for Theoretical Physics China, The Chinese Academy of Sciences, P. O. Box 2735 Beijing 100190 (China); Singapore-MIT Alliance for Research and Technology (SMART), Singapore 138602 (Singapore); Center for Advanced Study, Tsinghua University, Beijing 100084 (China)

    2014-01-28

    Single walled carbon nanotube's (SWCNT's) cross section can be flattened under hydrostatic pressure. One example is the cross section of a single walled carbon nanotube successively deforms from the original round shape to oval shape, then to peanut-like shape. At the transition point of reversible deformation between convex shape and concave shape, the side wall of nanotube is flattest. This flattest tube has many attractive properties. In the present work, an approximate approach is developed to determine the equilibrium shape of this unstrained flattest tube and the curvature distribution of this tube. Our results are in good agreement with recent numerical results, and can be applied to the study of pressure controlled electric properties of single walled carbon nanotubes. The present method can also be used to study other deformed inorganic and organic tube-like structures.

  16. Single-phase pressure-drop measurements over low void reactivity fuel

    International Nuclear Information System (INIS)

    Senaratne, U.P.M.; Leung, L.K.H.; Doria, F.J.; Lau, J.H.

    2006-01-01

    An experiment has been performed to obtain pressure-drop measurements over Low Reactivity Fuel (LVRF) bundles in Refrigerant-134a flow. Production LVRF bundles inserted into the test station with either an uncrept or a 5.1% crept flow channel. For comparison purposes, several production Bruce 37-element bundles were also included in the test string. Overall, the single-phase pressure drop of the LVRF bundle is slightly higher than that Bruce 37-element bundle. Pressure-drop measurements were used to derive bundle and loss coefficients for hydraulic calculations in safety analyses. Applying these loss coefficients, an assessment showed that the overall pressure drop over a string of 12 LVRF bundles (after conversion) remains less than that over a string of 13 Bruce 37-element fuel bundles (before conversion) at the Bruce Nuclear Generating Station. (author)

  17. Security of bottle to fill in a high pressure air

    Science.gov (United States)

    Todic, M.; Latinovic, T.; Golubovic-Bugarski, V.; Majstorovic, A.

    2018-01-01

    Charging the bottle of high pressure air isolation devices is performed by a high-pressure compressor. The charging time is in function of the compressor capacity and the intensity of the nominal pressure of the air in the bottle. However, in accident situations this time is long and therefore high-pressure accumulators are used where the filling time of the bottle of isolation apparatus has been drastically reduced. Due to the short filling time of the bottle through the air flow, there is a thermodynamic load of bottle material that could endanger the safety of users and other participants in the area. It is therefore necessary to determine the critical parameters of the rapid charge and their intensity.

  18. High pressure common rail injection system modeling and control.

    Science.gov (United States)

    Wang, H P; Zheng, D; Tian, Y

    2016-07-01

    In this paper modeling and common-rail pressure control of high pressure common rail injection system (HPCRIS) is presented. The proposed mathematical model of high pressure common rail injection system which contains three sub-systems: high pressure pump sub-model, common rail sub-model and injector sub-model is a relative complicated nonlinear system. The mathematical model is validated by the software Matlab and a virtual detailed simulation environment. For the considered HPCRIS, an effective model free controller which is called Extended State Observer - based intelligent Proportional Integral (ESO-based iPI) controller is designed. And this proposed method is composed mainly of the referred ESO observer, and a time delay estimation based iPI controller. Finally, to demonstrate the performances of the proposed controller, the proposed ESO-based iPI controller is compared with a conventional PID controller and ADRC. Copyright © 2016 ISA. Published by Elsevier Ltd. All rights reserved.

  19. Confinement of hydrogen at high pressure in carbon nanotubes

    Science.gov (United States)

    Lassila, David H [Aptos, CA; Bonner, Brian P [Livermore, CA

    2011-12-13

    A high pressure hydrogen confinement apparatus according to one embodiment includes carbon nanotubes capped at one or both ends thereof with a hydrogen-permeable membrane to enable the high pressure confinement of hydrogen and release of the hydrogen therethrough. A hydrogen confinement apparatus according to another embodiment includes an array of multi-walled carbon nanotubes each having first and second ends, the second ends being capped with palladium (Pd) to enable the high pressure confinement of hydrogen and release of the hydrogen therethrough as a function of palladium temperature, wherein the array of carbon nanotubes is capable of storing hydrogen gas at a pressure of at least 1 GPa for greater than 24 hours. Additional apparatuses and methods are also presented.

  20. High-pressure intrapleural chemotherapy: feasibility in the pig model

    Directory of Open Access Journals (Sweden)

    Facy Olivier

    2012-02-01

    Full Text Available Abstract Background The usual treatments for pleural malignancies are mostly palliative. In contrast, peritoneal malignancies are often treated with a curative intent by cytoreductive surgery and intraperitoneal chemotherapy. As pressure has been shown to increase antitumor efficacy, we applied the concept of high-pressure intracavitary chemotherapy to the pleural space in a swine model. Methods Cisplatin and gemcitabine were selected because of their antineoplasic efficacy in vitro in a wide spectrum of cancer cell lines. The pleural cavity of 21 pigs was filled with saline solution; haemodynamic and respiratory parameters were monitored. The pressure was increased to 15-25 cm H2O. This treatment was associated with pneumonectomy in 6 pigs. Five pigs were treated with chemotherapy under pressure. Results The combination of gemcitabine (100 mg/l and cisplatin (30 mg/l was highly cytotoxic in vitro. The maximum tolerated pressure was 20 cm H20, due to haemodynamic failure. Pneumonectomy was not tolerated, either before or after pleural infusion. Five pigs survived intrapleural chemotherapy associating gemcitabine and cisplatin with 20 cm H2O pressure for 60 min. Conclusions High-pressure intrapleural chemotherapy is feasible in pigs. Further experiments will establish the pharmacokinetics and determine whether the benefit already shown in the peritoneum is also obtained in the pleura.

  1. Condensation heat transfer on natural convection at the high pressure

    International Nuclear Information System (INIS)

    Jong-Won, Kim; Hyoung-Kyoun, Ahn; Goon-Cherl, Park

    2007-01-01

    The Regional Energy Research Institute for the Next Generation is to develop a small scale electric power system driven by an environment-friendly and stable small nuclear reactor. REX-10 has been developed to assure high system safety in order to be placed in densely populated region and island. REX-10 adopts the steam-gas pressurizer to assure the inherent safety. The thermal-hydraulic phenomena in the steam-gas pressurizer are very complex. Especially, the condensation heat transfer with noncondensable gas on the natural convection is important to evaluate the pressurizer behavior. However, there have been few investigations on the condensation in the presence of noncondensable gas at the high pressure. In this study, the theoretical model is developed to estimate the condensation heat transfer at the high pressure using heat and mass transfer analogy. The analysis results show good agreement with correlations and experimental data. It is found that the condensation heat transfer coefficient increases as the total pressure increases or the mass fraction of the non-condensable gas decreases. In addition, the heat transfer coefficient no more increases over the specific pressure

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

    DEFF Research Database (Denmark)

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

    2017-01-01

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

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

    International Nuclear Information System (INIS)

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

    2002-06-01

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

  4. Investigation of Methacrylic Acid at High Pressure Using Neutron Diffraction.

    Science.gov (United States)

    Marshall, William G; Urquhart, Andrew J; Oswald, Iain D H

    2015-09-10

    This article shows that pressure can be a low-intensity route to the synthesis of polymethacrylic acid. The exploration of perdeuterated methacrylic acid at high pressure using neutron diffraction reveals that methacrylic acid exhibits two polymorphic phase transformations at relatively low pressures. The first is observed at 0.39 GPa, where both phases were observed simultaneously and confirm our previous observations. This transition is followed by a second transition at 1.2 GPa to a new polymorph that is characterized for the first time. On increasing pressure, the diffraction pattern of phase III deteriorates significantly. On decompression phase III persists to 0.54 GPa before transformation to the ambient pressure phase. There is significant loss of signal after decompression, signifying that there has been a loss of material through polymerization. The orientation of the molecules in phase III provides insight into the possible polymerization reaction.

  5. Vibrational properties of ZnTe at high pressures

    International Nuclear Information System (INIS)

    Camacho, J.; Loa, I.; Syassen, K.; Cantarero, A.

    2002-01-01

    Raman spectra of ZnTe were measured under hydrostatic pressures up to 15 GPa at T=300 K. Results for the frequencies of first- and second-order Raman features of the zincblende phase (0-9.5 GPa) are used to set up a rigid-ion model of the phonon dispersion relations under pressure. Calculated phonon densities of states, mode Grueneisen parameters and the thermal expansion coefficient as a function of pressure are discussed. The effect of pressure on the widths and intensities of Raman spectral features is considered. Raman spectra of high-pressure phases of ZnTe are reported. These spectra indicate the possible existence of a new phase near 13 GPa, intermediate between the cinnabar and orthorhombic (Cmcm) phases of ZnTe. (author)

  6. Vibrational properties of ZnTe at high pressures

    Energy Technology Data Exchange (ETDEWEB)

    Camacho, J. [Max-Planck-Institut fuer Festkoerperforschung, Stuttgart (Germany) and Instituto de Ciencia de Materiales, Universidad de Valencia, Valencia (Spain)]. E-mail: Juana.Camacho@uv.es; Loa, I.; Syassen, K. [Max-Planck-Institut fuer Festkoerperforschung, Stuttgart (Germany); Cantarero, A. [Instituto de Ciencia de Materiales, Universidad de Valencia, Valencia (Spain)

    2002-02-04

    Raman spectra of ZnTe were measured under hydrostatic pressures up to 15 GPa at T=300 K. Results for the frequencies of first- and second-order Raman features of the zincblende phase (0-9.5 GPa) are used to set up a rigid-ion model of the phonon dispersion relations under pressure. Calculated phonon densities of states, mode Grueneisen parameters and the thermal expansion coefficient as a function of pressure are discussed. The effect of pressure on the widths and intensities of Raman spectral features is considered. Raman spectra of high-pressure phases of ZnTe are reported. These spectra indicate the possible existence of a new phase near 13 GPa, intermediate between the cinnabar and orthorhombic (Cmcm) phases of ZnTe. (author)

  7. High pressure Raman study of BaMoO4

    International Nuclear Information System (INIS)

    Christofilos, D.; Kourouklis, G.A.; Arvanitidis, J.; Kampasakali, E.; Papagelis, K.; Ves, S.

    2004-01-01

    The structural stability of polycrystalline BaMoO 4 under hydrostatic pressure has been investigated by means of Raman spectroscopy up to 8 GPa. Raman spectra reveal a pressure induced phase transition at ∝5.8 GPa. Upon pressure release the structure reverts to its ambient pressure scheelite (CaWO 4 ) structure with no observable hysteresis. The large number of Raman active modes of the high pressure phase suggests either an increase of the size of the unit cell and/or a non-centrosymmetric structure leading to the activation of the ungerade modes of the scheelite structure. (copyright 2004 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  8. High Field Magnetization of Tb Single Crystals

    DEFF Research Database (Denmark)

    Roeland, L. W.; Cock, G. J.; Lindgård, Per-Anker

    1975-01-01

    The magnetization of Tb single crystals was measured in magnetic fields to 34T along the hard direction at temperature of 1.8, 4.2, 65.5 and 77K, and along with easy direction at 4.2 and 77K. The data are compared with the results of a self-consistent spin wave calculation using a phenomenological...

  9. High-Performance Single Nanowire Tunnel Diodes

    DEFF Research Database (Denmark)

    Wallentin, Jesper; Persson, Johan Mikael; Wagner, Jakob Birkedal

    2010-01-01

    We demonstrate single nanowire tunnel diodes with room temperature peak current densities of up to 329 A/cm(2). Despite the large surface to volume ratio of the type-II InP-GaAs axial heterostructure nanowires, we measure peak to valley current ratios (PVCR) of up to 8.2 at room temperature and 27...

  10. A Manganin Thin Film Ultra-High Pressure Sensor for Microscale Detonation Pressure Measurement

    Directory of Open Access Journals (Sweden)

    Guodong Zhang

    2018-03-01

    Full Text Available With the development of energetic materials (EMs and microelectromechanical systems (MEMS initiating explosive devices, the measurement of detonation pressure generated by EMs in the microscale has become a pressing need. This paper develops a manganin thin film ultra-high pressure sensor based on MEMS technology for measuring the output pressure from micro-detonator. A reliable coefficient is proposed for designing the sensor’s sensitive element better. The sensor employs sandwich structure: the substrate uses a 0.5 mm thick alumina ceramic, the manganin sensitive element with a size of 0.2 mm × 0.1 mm × 2 μm and copper electrodes of 2 μm thick are sputtered sequentially on the substrate, and a 25 μm thick insulating layer of polyimide is wrapped on the sensitive element. The static test shows that the piezoresistive coefficient of manganin thin film is 0.0125 GPa−1. The dynamic experiment indicates that the detonation pressure of micro-detonator is 12.66 GPa, and the response time of the sensor is 37 ns. In a word, the sensor developed in this study is suitable for measuring ultra-high pressure in microscale and has a shorter response time than that of foil-like manganin gauges. Simultaneously, this study could be beneficial to research on ultra-high-pressure sensors with smaller size.

  11. A Manganin Thin Film Ultra-High Pressure Sensor for Microscale Detonation Pressure Measurement.

    Science.gov (United States)

    Zhang, Guodong; Zhao, Yulong; Zhao, Yun; Wang, Xinchen; Wei, Xueyong; Ren, Wei; Li, Hui; Zhao, You

    2018-03-01

    With the development of energetic materials (EMs) and microelectromechanical systems (MEMS) initiating explosive devices, the measurement of detonation pressure generated by EMs in the microscale has become a pressing need. This paper develops a manganin thin film ultra-high pressure sensor based on MEMS technology for measuring the output pressure from micro-detonator. A reliable coefficient is proposed for designing the sensor's sensitive element better. The sensor employs sandwich structure: the substrate uses a 0.5 mm thick alumina ceramic, the manganin sensitive element with a size of 0.2 mm × 0.1 mm × 2 μm and copper electrodes of 2 μm thick are sputtered sequentially on the substrate, and a 25 μm thick insulating layer of polyimide is wrapped on the sensitive element. The static test shows that the piezoresistive coefficient of manganin thin film is 0.0125 GPa -1 . The dynamic experiment indicates that the detonation pressure of micro-detonator is 12.66 GPa, and the response time of the sensor is 37 ns. In a word, the sensor developed in this study is suitable for measuring ultra-high pressure in microscale and has a shorter response time than that of foil-like manganin gauges. Simultaneously, this study could be beneficial to research on ultra-high-pressure sensors with smaller size.

  12. Pressure Relief Devices for High-Pressure Gaseous Storage Systems: Applicability to Hydrogen Technology

    Energy Technology Data Exchange (ETDEWEB)

    Kostival, A.; Rivkin, C.; Buttner, W.; Burgess, R.

    2013-11-01

    Pressure relief devices (PRDs) are viewed as essential safety measures for high-pressure gas storage and distribution systems. These devices are used to prevent the over-pressurization of gas storage vessels and distribution equipment, except in the application of certain toxic gases. PRDs play a critical role in the implementation of most high-pressure gas storage systems and anyone working with these devices should understand their function so they can be designed, installed, and maintained properly to prevent any potentially dangerous or fatal incidents. As such, the intention of this report is to introduce the reader to the function of the common types of PRDs currently used in industry. Since high-pressure hydrogen gas storage systems are being developed to support the growing hydrogen energy infrastructure, several recent failure incidents, specifically involving hydrogen, will be examined to demonstrate the results and possible mechanisms of a device failure. The applicable codes and standards, developed to minimize the risk of failure for PRDs, will also be reviewed. Finally, because PRDs are a critical component for the development of a successful hydrogen energy infrastructure, important considerations for pressure relief devices applied in a hydrogen gas environment will be explored.

  13. 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.

  14. Pressure relief, cold foam or static air? A single center, prospective, controlled randomized clinical trial in a Dutch nursing home.

    Science.gov (United States)

    van Leen, Martin; Hovius, Steven; Neyens, Jacques; Halfens, Ruud; Schols, Jos

    2011-02-01

    At present, the evidence regarding the type of mattress that is the best for preventing pressure ulcers is not convincing. In a single center, prospective, controlled trial we compared a static air overlay mattress (no electric pump needed) on top of a cold foam mattress with a cold foam mattress alone on pressure ulcer incidence in nursing home residents. 83 Patients were included in the study with a score lower than 12 points on the Norton scale and no pressure ulcer at the start of the study. 42 Patients received a cold foam mattress and 41 patients received a static air overlay on top of that cold foam mattress. Out of bed we standardized the pressure reduction in sitting position by using a static air cushion in both groups. Patients were checked weekly in both groups for pressure ulcers. Only when there were signs of developing a pressure ulcer grade 2 or higher, repositioning by our nursing home pressure ulcer protocol (PU protocol) was put into practice. Seven patients (17.1%) on a cold foam mattress and two (4.8%) on a static air mattress developed a pressure ulcer grade 2 or more. There was no difference regarding pressure ulcer incidence between patients with a high risk (Norton 5-8) and patients with a medium risk (Norton 9-12). In 5 out of 7 patients who developed a pressure ulcer on a foam mattress the ulcers showed no healing using our PU protocol. In the static air group all pressure ulcers healed by regular treatment according to our PU protocol. In this study, static air overlay mattresses provided a better prevention than cold foam mattresses alone (4.8% versus 17.1%). The Norton scores of the patients in both groups did not change during the 6 month trial period. Our decision to use repositioning only when there were signs of a pressure ulcer seems to be acceptable when a static air overlay is in position. However, the score of 17.1% development (incidence) of pressure ulcers in the foam group may stress the need of repositioning when using only

  15. Design Concepts for Low Aspect Ratio High Pressure Turbines for High Bypass Ratio Turbofans, Phase II

    Data.gov (United States)

    National Aeronautics and Space Administration — The performance gains and weight reductions from using Ceramic Matrix Composite(CMC) turbine blades in both the High Pressure Turbine(HPT) and Low Pressure...

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

    Data.gov (United States)

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

  17. A study on the relief of shell wall thinning of high pressure feedwater heater

    International Nuclear Information System (INIS)

    Kim, Hyung Joon; Park, Sang Hoon; Seo, Hyuk Ki; Kim, Kyung Hoon; Hwang, Kyung Mo

    2008-01-01

    Feedwater heaters of many nuclear power plants have recently experienced severe wall thinning damage, which will increase as operating time progresses. Several nuclear power plants in Korea have experienced wall thinning damage in the area around the impingement baffle-installed downstream of the high pressure turbine extraction stream line- inside number 5A and 5B feedwater heaters. At that point, the extracted steam from the high pressure turbine is two phase fluid at high temperature, high pressure, and high speed. Since it flows in reverse direction after impinging the impingement baffle, the shell wall of the number 5 high pressure feedwater heater may be affected by flow-accelerated corrosion. This paper describes operation of experience and numerical analysis composed similar condition with real high pressure feedwater heater. This study applied squared, curved and new type impingement baffle plates to feedwater heater same as previous study. In addition, it shows difference of pressure distribution and value between single phase and two phase based on experience and numerical analysis

  18. High Intracranial Pressure Induced Injury in the Healthy Rat Brain.

    Science.gov (United States)

    Dai, Xingping; Bragina, Olga; Zhang, Tongsheng; Yang, Yirong; Rao, Gutti R; Bragin, Denis E; Statom, Gloria; Nemoto, Edwin M

    2016-08-01

    We recently showed that increased intracranial pressure to 50 mm Hg in the healthy rat brain results in microvascular shunt flow characterized by tissue hypoxia, edema, and increased blood-brain barrier permeability. We now determined whether increased intracranial pressure results in neuronal injury by Fluoro-Jade stain and whether changes in cerebral blood flow and cerebral metabolic rate for oxygen suggest nonnutritive microvascular shunt flow. Intracranial pressure was elevated by a reservoir of artificial cerebrospinal fluid connected to the cisterna magna. Arterial blood gases, cerebral arterial-venous oxygen content difference, and cerebral blood flow by MRI were measured. Fluoro-Jade stain neurons were counted in histologic sections of the right and left dorsal and lateral cortices and hippocampus. University laboratory. Male Sprague Dawley rats. Arterial pressure support if needed by IV dopamine infusion and base deficit corrected by sodium bicarbonate. Fluoro-Jade stain neurons increased 2.5- and 5.5-fold at intracranial pressures of 30 and 50 mm Hg and cerebral perfusion pressures of 57 ± 4 (mean ± SEM) and 47 ± 6 mm Hg, respectively (p intracranial pressure and decreased cerebral metabolic rate for oxygen. High intracranial pressure likely caused neuronal injury because of a transition from normal capillary flow to nonnutritive microvascular shunt flow resulting in tissue hypoxia and edema, and it is manifest by a reduction in the cerebral metabolic rate for oxygen.

  19. High pressure injection injuries: a serious occupational hazard.

    Science.gov (United States)

    Mrvos, R; Dean, B S; Krenzelok, E P

    1987-01-01

    High pressure injection equipment such as airless paint sprayers, high pressure grease guns, and fuel injection apparatus constitute a serious safety hazard resulting in significant morbidity. These devices are capable of delivering contaminants such as paint, solvents, and grease at pressures ranging from 600-12,000 psi. This allows the substance to penetrate through a minute skin wound and to spread widely through fascial planes and tendon sheaths and to produce significant vascular compression and systemic toxicity. High pressure injection injuries frequently result in amputation. Fifty-five suspected high pressure injection injury cases were evaluated. Twenty were determined to be actual injection injuries from equipment producing pressures in the range of 1,500-12,000 psi. The injected contaminants included latex paint, mineral spirits, and concrete sealer. Fourteen injuries involved digits. Digital amputation was necessary in three patients. Hospital admissions averaged 6.5 days. Successful management of these cases involves awareness of the impending problem and rapid referral of the patient to an emergency department and to a competent orthopedic or plastic surgeon.

  20. High-pressure properties of diaspore, AlO(OH)

    Science.gov (United States)

    Friedrich, A.; Wilson, D. J.; Haussühl, E.; Winkler, B.; Morgenroth, W.; Refson, K.; Milman, V.

    2007-04-01

    The structural compression mechanism and compressibility of diaspore, AlO(OH), were investigated by in situ single-crystal synchrotron X-ray diffraction at pressures up to 7 GPa using the diamond-anvil cell technique. Complementary density functional theory based model calculations at pressures up to 40 GPa revealed additional information on the pressure-dependence of the hydrogen-bond geometry and the vibrational properties of diaspore. A fit of a second-order Birch-Murnaghan equation of state to the p-V data resulted in the bulk modulus B 0 = 150(3) GPa and B 0 = 150.9(4) GPa for the experimental and theoretical data, respectively, while a fit of a third-order Birch-Murnaghan equation of state resulted in B 0 = 143.7(9) GPa with its pressure derivative B' = 4.4(6) for the theoretical data. The compression is anisotropic, with the a-axis being most compressible. The compression of the crystal structure proceeds mainly by bond shortening, and particularly by compression of the hydrogen bond, which crosses the channels of the crystal structure in the (001) plane, in a direction nearly parallel to the a-axis, and hence is responsible for the pronounced compression of this axis. While the hydrogen bond strength increases with pressure, a symmetrisation is not reached in the investigated pressure range up to 40 GPa and does not seem likely to occur in diaspore even at higher pressures. The stretching frequencies of the O-H bond decrease approximately linearly with increasing pressure, and therefore also with increasing O-H bond length and decreasing hydrogen bond length.

  1. Determination of the partial pressure of thallium in high-pressure lamp arcs: A comparative study

    International Nuclear Information System (INIS)

    Karabourniotis, D.; Couris, S.; Damelincourt, J.J.; Aubes, M.

    1986-01-01

    The partial pressure of thallium in high-pressure Hg-TlI discharges with different mercury, thallium, and electron pressures has been measured by using the optically thin line Tl 655 nm and the self-reversed line Tl 535 nm. The partial pressure of the arc axis has been measured from the line Tl 655nm. The effective partial pressure has been measured from the self-reversed line Tl 535 nm on the basis of the multiparameter method, and it has been calculated from the known axis pressure of thallium and the calculation of its radial variation by taking into account the chemical reactions. The experimental results confirm the dispersion character of the blue wing of the line Tl 535 nm. The systematic difference obtained between the measured and calculated effective pressure, particularly at the moment of minimum electron density, may be interpreted by deviations from the local thermodynamic equilibrium (LTE) caused by overpopulation of the upper level of the line Tl 535 nm

  2. Cryogenic Impinging Jets Subjected to High Frequency Transverse Acoustic Forcing in a High Pressure Environment

    Science.gov (United States)

    2016-07-27

    Lake City, Utah; July 27, 2016 Prepared in collaboration with Sierra Lobo, Inc. 14. ABSTRACT An experimental study has been conducted to explore...visually prominent, the impingement sheet was subjected to incremental pressure amplitudes in a pressure anti-node (PAN) and pressure node (PN...been conducted to explore the coupling between the impact waves created by impinging jets and high frequency acoustic pressure perturbations. High

  3. High-pressure structural study of Ammonium Perchlorate

    Science.gov (United States)

    Stavrou, Elissaios; Zaug, Joseph; Bastea, Sorin; Grivickas, Paulius; Greenberg, Eran; Kunz, Martin

    Ammonium perchlorate (AP) with the chemical formula NH4ClO4 is a powerful energetic oxidizer used as an ingredient in rocket propellants and explosive formulations. For this reason, its structural properties under extreme conditions have attracted considerable attention (M. Dunuwille et al., S. Hunter et al.). However, its structural properties under pressure are not completely understood. In addition to its importance as an energetic oxidizer, AP is one of the simplest supramolecular systems. Thus, a structural study of AP under pressure can provide crucial information in the context of the emerging field of high pressure supramolecular chemistry. Ammonium perchlorate has been studied using x-ray diffraction and Raman spectroscopy up to the record pressure of 40 GPa. The results reveal a pressure-induced first order phase transition at 4 GPa, in agreement with previous studies. However, preliminary analysis of our results contradicts with the previously proposed high-pressure phase, as determined by neutron diffraction. No further structural phase transitions have been observed up to the highest pressure of this study. Intermolecular bonding between NH4 and ClO4 ions will be discussed based on Raman spectroscopy measurements. This work was performed under the auspices of the U. S. Department of Energy by Lawrence Livermore National Security, LLC under Contract DE-AC52-07NA27344.

  4. Microwave Wire Interrogation Method Mapping Pressure under High Temperatures

    Directory of Open Access Journals (Sweden)

    Xiaoyong Chen

    2017-12-01

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

  5. High-performance single nanowire tunnel diodes.

    Science.gov (United States)

    Wallentin, Jesper; Persson, Johan M; Wagner, Jakob B; Samuelson, Lars; Deppert, Knut; Borgström, Magnus T

    2010-03-10

    We demonstrate single nanowire tunnel diodes with room temperature peak current densities of up to 329 A/cm(2). Despite the large surface to volume ratio of the type-II InP-GaAs axial heterostructure nanowires, we measure peak to valley current ratios (PVCR) of up to 8.2 at room temperature and 27.6 at liquid helium temperature. These sub-100-nm-diameter structures are promising components for solar cells as well as electronic applications.

  6. Foam glass obtained through high-pressure sintering

    DEFF Research Database (Denmark)

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

    2018-01-01

    are subjected to a second heat treatment above the glass transition temperature at atmospheric pressure. This heat treatment causes expansion of the pores due to high internal gas pressure. We found that the foaming ability strongly depends on the gas pressure applied during sintering, and on the kinetic......Foam glasses are usually prepared through a chemical approach, that is, by mixing glass powder with foaming agents, and heating the mixture to a temperature above the softening point (106.6 Pa s) of the glass. The foaming agents release gas, enabling expansion of the sintered glass. Here, we use...... a physical foaming approach to prepare foam glass. First, closed pores filled with inert gases (He, Ar, or N2) are physically introduced into a glass body by sintering cathode ray tube (CRT) panel glass powder at high gas pressure (5‐25 MPa) at 640°C and, then cooled to room temperature. The sintered bodies...

  7. High pressure-phases in the scandium-gallium system

    International Nuclear Information System (INIS)

    Popova, S.V.; Fomicheva, L.N.; Putro, V.G.

    1980-01-01

    Investigated are the crystalline structure and composition of scandium-gallium alloys, which can be prepared under high pressure. Scandium gallide synthesis has been carried out under 77 kbar constant pressure, the temperature has been changed from 200 to 1000 deg C. It is shown, that high pressure effect causes complication of state diagram of the scandium-gallium system. Three intermediate phases are found in the system at p=77 kbar within the range from 200 to 1000 deg C :Sc 5 Ga 3 (Mn 5 Si 3 type)- stable under atmospheric pressure and ScGa 2 gallides, metastable under normal conditions (ZrGa 2 type), and ScGa 3 (Cu 3 Au type)

  8. High-Pressure Microscopy for Studying Molecular Motors.

    Science.gov (United States)

    Nishiyama, Masayoshi

    2015-01-01

    Movement is a fundamental characteristic of all living things. This biogenic function is carried out by various nanometer-sized molecular machines. Molecular motor is a typical molecular machinery in which the characteristic features of proteins are integrated; these include enzymatic activity, energy conversion, molecular recognition and self-assembly. These biologically important reactions occur with the association of water molecules that surround the motors. Applied pressures can alter the intermolecular interactions between the motors and water. In this chapter we describe the development of a high-pressure microscope and a new motility assay that enables the visualization of the motility of molecular motors under conditions of high-pressure. Our results demonstrate that applied pressure dynamically changes the motility of molecular motors such as kinesin, F1-ATPase and bacterial flagellar motors.

  9. 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

    quadrupolar broadening which is rather unexpected given the cubic symmetry of the lattice. Wether this quadrupolar broadening is caused by strain in the sample or is the manifestation of a charge density variation that breaks the cubic symmetry remains unclear. To investigate the effect of pressure on the pseudogap of high temperature superconductors, temperature dependent {sup 17}O and {sup 63}Cu NMR shift measurements were carried out on YBa{sub 2}Cu{sub 4}O{sub 8} up to 63 kbar for the first time. These experiments reveal that with increasing pressure the spin shift {sup 17}K{sub s}(p,T) of planar oxygen and the spin shift {sup 63}K{sub s}(p,T) of planar copper increase and become more Fermi liquid like above the superconducting transition temperature T{sub c}. At first glance this seems similar to the effect of doping in other high temperature superconductors [9,142] and indicates the closing of the pseudogap with pressure. Wether or not this represents a general behavior of cuprates under pressure remains to be determined in the future by investigating other high temperature superconductors under comparable conditions. Furthermore, based on a scaling behavior of the spin shifts with pressure it is concluded that a two component spin susceptibility is present in the copper-oxide plane. One component displays the pseudogap temperature dependence and decreases with pressure while the other component is Fermi liquid like and increases strongly with pressure. However, the Fermi liquid like component is small at ambient pressure which may explain why earlier shift data of YBa2Cu4O8 have been interpreted in terms of a single component spin susceptibility [106, 128]. In the present work, its presence is only revealed due to the application of sufficiently high pressures. The two components in YBa{sub 2}Cu{sub 4}O{sub 8} are similar to those observed in recent ambient pressure studies on La{sub 1.85}Sr{sub 0.15}CuO{sub 4} [108] and HgBa{sub 2}CuO{sub 4+x} [111, 112], indicating

  10. Synergistic effect of high pressure processing and Lactobacillus casei antimicrobial activity against pressure resistant Listeria monocytogenes.

    Science.gov (United States)

    Chung, Hyun-Jung; Yousef, Ahmed E

    2010-09-30

    The purpose of this study was to evaluate combinations of high pressure processing (HPP) and Lactobacillus casei antimicrobial activity against Listeria monocytogenes strains with variation in pressure resistance in culture and in a food model. In culture, combination of HPP (350 MPa, for 1-20 min) and Lb. casei cell extract (CE, 32 CEAU/ml) showed a significant synergistic bactericidal effect (P5 log(10)CFU/ml. Synergy between CE and HPP was most evident in the pressure-resistant strain, OSY-8578. Similar result was observed in meat products where high pressure (500 MPa for 1 min), and high-activity CE (100 CEAU/g) caused >5 log reduction in the viability of L. monocytogenes Scott A. The combination treatment resulted in the absence of peaks associated with cellular components in DSC thermogram suggesting that the presence of CE may have caused a considerable damage to cellular components during the high pressure treatment. Copyright 2010 Elsevier B.V. All rights reserved.

  11. Blood Pressure Control with a Single-Pill Combination of Indapamide Sustained-Release and Amlodipine in Patients with Hypertension: The EFFICIENT Study

    OpenAIRE

    Jadhav, Uday; Hiremath, Jagdish; Namjoshi, Deepak J.; Gujral, Vinod K.; Tripathi, Kamlakar K.; Siraj, Mohammad; Shamanna, Paramesh; Safar, Michel

    2014-01-01

    OBJECTIVE: Despite antihypertensive treatment, most hypertensive patients still have high blood pressure (BP), notably high systolic blood pressure (SBP). The EFFICIENT study examines the efficacy and acceptability of a single-pill combination of sustained-release (SR) indapamide, a thiazide-like diuretic, and amlodipine, a calcium channel blocker (CCB), in the management of hypertension. METHODS: Patients who were previously uncontrolled on CCB monotherapy (BP≥140/90 mm Hg) or were previousl...

  12. Under pressure: progressively enlarging facial mass following high-pressure paint injection injury.

    Science.gov (United States)

    Mushtaq, Jameel; Walker, Abigail; Hunter, Ben

    2016-01-19

    High-pressure paint injection injuries are relatively rare industrial accidents and almost exclusively occur on the non-dominant hand. A rarely documented complication of these injuries is the formation of a foreign body granuloma. We report a case of a 33-year-old man presenting with extensive facial scarring and progressive right paranasal swelling 7 years after a high-pressure paint injury. After imaging investigations, an excision of the mass and revision of scarring was performed. Access to the mass was gained indirectly through existing scarring over the nose to ensure an aesthetic result. Histological analysis revealed a florid granulomatous foreign body reaction to retained paint. To the best of our knowledge, this is the first reported case of a facial high-pressure paint injury with consequent formation of a foreign body granuloma. 2016 BMJ Publishing Group Ltd.

  13. L-tyrosine hydrochloride crystals under high pressures via Raman Spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Santos, C.A.A.S.; Facanha Filho, P.F.; Santos, A.O. dos; Ribeiro, L.H.L.; Victor, F.M.S.; Abreu, D.C.; Carvalho, J.O.; Soares, R.A.; Sousa, J.C.F.; Lima, R.C.; Cavaignac, A.O. [Universidade Federal do Maranhao (UFMA), MA (Brazil)

    2016-07-01

    Full text: Amino acid single crystals have been attracted researchers in recent years due to their potential applications as second harmonic generator. The goal of this work is to produce semi organic single crystals of L-tyrosine hydrochloride (LTHCl) and verify the behavior of their vibrational normal modes under high pressures and the stability of material in these conditions extremes. The LTHCl single crystals were produced for solubilization of amino acid L-tyrosine in hydrochloric acid by slow evaporation technique of the solvent in room temperature. The technique of X-ray diffraction (XRD) and the refinement of structure by the Rietveld method were used to confirm the crystal structure. The LTHCl crystal belongs to the monoclinic crystal system having two molecules per unit cell. The refinement by the Rietveld method showed good results with Rwp = 8.49% and Rp = 6.29% with S = 1.13. Raman scattering measurements as a function of pressure was performed in a piece of crystal from the ambient pressure to 7.2 GPa and Nujol was used as pressure medium. It was observed the appearance of a weak band around 163 cm-1 between pressures of 0.5 and 1.0 GPa, which characterize an phase transition undergone by the crystal. Moreover, this band gains intensity as pressure increases while gradual decreasing relative intensity of the very strong band at 123 cm-1 for all range of pressure also was observed. In fact, almost all bands of the spectra have undergone strong decreasing up to 7.2 GPa. However, on release of pressure the crystal has reached the original phase again. Therefore, the results showed this material cannot be suitable for the application (NLO) in this range of pressure. (author)

  14. Investigation of Acrylic Acid at High Pressure Using Neutron Diffraction

    OpenAIRE

    Johnston, Blair F.; Marshall, William G.; Parsons, Simon; Urquhart, Andrew J.; Oswald, Iain D. H.

    2014-01-01

    This article details the exploration of perdeuterated acrylic acid at high pressure using neutron diffraction. The structural changes that occur in acrylic acid-d4 are followed via diffraction and rationalized using the Pixel method. Acrylic acid undergoes a reconstructive phase transition to a new phase at ∼0.8 GPa and remains molecular to 7.2 GPa before polymerizing on decompression to ambient pressure. The resulting product is analyzed via Raman and FT-IR spectroscopy and differential scan...

  15. Plastic reactor suitable for high pressure and supercritical fluid electrochemistry

    OpenAIRE

    Branch, Jack; Alibouri, Mehrdad; Cook, David A.; Richardson, Peter; Bartlett, Philip N.; Matefi-Tempfli, Maria; Matefi-Tempfli, Stefan; Bampton, Mark; Cookson, Tamsin; Connell, Phil; Smith, David

    2017-01-01

    The paper describes a reactor suitable for high pressure, particularly supercritical fluid, electrochemistry and electrodeposition at pressures up to 30 MPa at 115°C. The reactor incorporates two key, new design concepts; a plastic reactor vessel and the use of o-ring sealed brittle electrodes. These two innovations widen what can be achieved with supercritical fluid electrodeposition. The suitability of the reactor for electroanalytical experiments is demonstrated by studies of the voltammet...

  16. Distensibility and pressure-flow relationship of the pulmonary circulation. I. Single-vessel model.

    Science.gov (United States)

    Bshouty, Z; Younes, M

    1990-04-01

    To ascertain the relative contributions of vascular distensibility and nonhomogeneous behavior within the pulmonary circulation to the distinctive nonlinear relationship between inflow pressure (Pin) and flow [pressure-flow (P-F) relationship] and between Pin and outflow pressure (Pout) at constant flow (Pin-Pout relationship), we developed a multibranched model in which the elastic behavior of, and forces acting on, individual branches can be varied independently. The response of the multibranched model is described in the companion article (J. Appl. Physiol. 68: 1514-1527, 1990). Here we describe the methods used and the responses of single components of the larger model. Perivascular pressure is modeled as a function of intravascular and transpulmonary pressures (Pv and Ptp, respectively) and vessel length as a function of lung volume. These and the relationship between vascular area (A) and transmural pressure (Ptm) were modeled primarily from the dog data of Smith and Mitzner (J. Appl. Physiol. 48: 450-467, 1980). Vasomotor tone is modeled as a radial collapsing pressure (Pt) in the same plane as Ptm. In view of lack of information about the relationship between Pt and A for a given active state, different patterns were assumed that span a wide range of possible relationships. The P-F and Pin-Pout relationships of single vessels were very similar to those reported for the entire intact circulation. Of note, the slope of the Pin-Pout relationship in the low Pout range (0-5 Torr) was very low (less than 0.25) and increased gradually with Pout toward unity. Vasomotor tone caused an apparent parallel shift in the P-F relationship in the physiological flow range of the dog (2-8 l/min) regardless of the pattern used to model the Pt vs. A relationship; different patterns affected the P-F relationship only over the low flow range before the parallel shift was established.

  17. A system for incubations at high gas partial pressure

    Directory of Open Access Journals (Sweden)

    Patrick eSauer

    2012-02-01

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

  18. Elasticity of methane hydrate phases at high pressure

    Energy Technology Data Exchange (ETDEWEB)

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

    2016-04-21

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

  19. Blue emitting organic semiconductors under high pressure: status and outlook

    Science.gov (United States)

    Knaapila, Matti; Guha, Suchismita

    2016-06-01

    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 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 highlighted by high pressure optical spectroscopy whilst analogous x-ray diffraction experiments remain less frequent. By focusing on a class of blue-emitting π-conjugated polymers, polyfluorenes, this article reviews optical spectroscopic studies under hydrostatic pressure, addressing the impact of molecular 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 of pressure-driven intra- and interchain interactions. Key obstacles to obtain further advances are identified and experimental methods to resolve them are suggested.

  20. Blue emitting organic semiconductors under high pressure: status and outlook.

    Science.gov (United States)

    Knaapila, Matti; Guha, Suchismita

    2016-06-01

    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 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 highlighted by high pressure optical spectroscopy whilst analogous x-ray diffraction experiments remain less frequent. By focusing on a class of blue-emitting π-conjugated polymers, polyfluorenes, this article reviews optical spectroscopic studies under hydrostatic pressure, addressing the impact of molecular 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 of pressure-driven intra- and interchain interactions. Key obstacles to obtain further advances are identified and experimental methods to resolve them are suggested.

  1. Theoretical Predictions of Phase Transitions at Ultra-high Pressures

    Science.gov (United States)

    Boates, Brian

    2013-06-01

    We present ab initio calculations of the high-pressure phase diagrams of important planetary materials such as CO2, MgSiO3, and MgO. For CO2, we predict a series of distinct liquid phases over a wide pressure (P) and temperature (T) range, including a first-order transition to a dense polymer liquid. We have computed finite-temperature free energies of liquid and solid CO2 phases to determine the melting curve beyond existing measurements and investigate possible phase separation transitions. The interaction of these phase boundaries with the mantle geotherm will also be discussed. Furthermore, we find evidence for a vast pressure-temperature regime where molten MgSiO3 decomposes into liquid SiO2 and solid MgO, with a volume change of approximately 1.2 percent. The demixing transition is driven by the crystallization of MgO ? the reaction only occurs below the high-pressure MgO melting curve. The predicted transition pressure at 10,000 K is in close proximity to an anomaly reported in recent laser-driven shock experiments of MgSiO3. We also present new results for the high-pressure melting curve of MgO and its B1-B2 solid phase transition, with a triple point near 364 GPa and 12,000 K.

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

    Directory of Open Access Journals (Sweden)

    Oleksandr O. Kurakevych

    2016-10-01

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

  3. Superconductivity of divalent Chevrel phases at very high pressures

    International Nuclear Information System (INIS)

    Yao, Y.S.; Guertin, R.P.; Hinks, D.G.; Jorgensen, J.; Capone II, D.W.

    1988-01-01

    The electrical resistivity and the superconducting transition temperatures were examined for three representative divalent Chevrel phase systems, SnMo 6 S 8 , EuMo 6 S 8 , and BaMo 6 S 8 , as a function of hydrostatic pressure to 2 GPa and in quasihydrostatic pressures to 10 GPa. In all systems, T/sub c/ is depressed to 0 K for sufficiently large pressures. For the Sn- and Eu-based systems, both highly purified samples and samples with controlled oxygen content were used. In an oxygenated SnMo 6 S 8 sample (less than 3% O 2 substituted for the S atoms) the pressure threshold and maximum T/sub c/ are 40% lower than in the pure sample, but for P>3.5 GPa the T/sub c/-P phase diagrams nearly coincide, with T/sub c/ reaching zero at an extrapolated pressure of about 12 GPa. In pure EuMo 6 S 8 , superconductivity appears only above a threshold pressure of about 1 GPa and is depressed to 0 K above 4.5 GPa. In an oxygenated sample the maximum T/sub c/ and the threshold pressure are depressed, and above about 3.5 GPa the T/sub c/-P phase diagrams coincide, as in the Sn-based system, although T/sub c/ is then rapidly depressed to 0 K at about 4.5 GPa. In a highly purified BaMo 6 S 8 sample superconductivity appears above about 2 GPa and is depressed to 0 K at extrapolated pressures above 12 GPa. A full transition to the zero-resistance superconducting state is observed in BaMo 6 S 8 . The data are discussed in terms of a model linking the rhombohedral-to-triclinic structural transition, the superconducting transition temperature, and the role of pressure in suppressing the structural transition

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

    Science.gov (United States)

    Wisniewiski, David

    2014-03-01

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

  5. Thermal high pressure hydrogenolysis II. The thermal high pressure hydrocracking of fluorene

    NARCIS (Netherlands)

    Oltay, Ernst; Penninger, Johannes M.L.; Konter, Willem A.N.

    1973-01-01

    The thermal hydrocracking of fluorene was investigated in the temperature range of 400 to 480 °C and hydrogen pressures of up to 375 atm. As main reaction products were found 2-methylbiphenyl, biphenyl, toluene and benzene. They account for about 90% of the converted fluorene. Only very low

  6. Experimental studies on radiation effects under high pressure oxygen

    International Nuclear Information System (INIS)

    Fujimura, Eisuke

    1974-01-01

    The effect of oxygen tension on the radiosensitivity of tumor cells is well known, but its clinical application for radiotherapy is not yet established. Rabbits with V x 2 carcinoma in the maxilla were irradiated by 60 Co under high pressure oxygen (experimental group), and compared with those treated in air (control group). For the purpose of examining the clinical effects of high pressure oxygen, an experiment was made in vivo. The following items were compared respectively: a) Tumor regression effect b) Tumor clearance rate c) Survival days d) Half size reduction time e) Inhibition of DNA synthesis in the tumor tissue. Results obtained were as follows: a) 56 per cent of animals showed tumor regression in the experimental group, whereas it occured 26 per cent in the control group. b) 53 per cent of animals showed tumor disappearance in the experimental group, while it was observed only in 13 per cent in the control group. c) Only 2 of 30 rabbits irradiated in air survived over 180 days, whereas 11 of 30 rabbits survived meanwhile in the group irradiated under high pressure oxygen. d) About 11 days were necessary to reduce the tumor size by half after irradiation in the group under high pressure oxygen, while it took 17 days in the group treated in normal air. e) DNA synthesis was inhibited more prominently in the group irradiated under high pressure oxygen in normal air. (author)

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2017-11-14

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

  8. Application and possible benefits of high hydrostatic pressure or high-pressure homogenization on beer processing: A review.

    Science.gov (United States)

    Santos, Lígia Mr; Oliveira, Fabiano A; Ferreira, Elisa Hr; Rosenthal, Amauri

    2017-10-01

    Beer is the most consumed beverage in the world, especially in countries such as USA, China and Brazil.It is an alcoholic beverage made from malted cereals, and the barley malt is the main ingredient, added with water, hops and yeast. High-pressure processing is a non-traditional method to preserve food and beverages. This technology has become more interesting compared to heat pasteurization, due to the minimal changes it brings to the original nutritional and sensory characteristics of the product, and it comprises two processes: high hydrostatic pressure, which is the most industrially used process, and high-pressure homogenization. The use of high pressure almost does not affect the molecules that are responsible for the aroma and taste, pigments and vitamins compared to the conventional thermal processes. Thus, the products processed by high-pressure processing have similar characteristics compared to fresh products, including beer. The aim of this paper was to review what has been investigated about beer processing using this technology regarding the effects on physicochemical, microbiology and sensory characteristics and related issues. It is organized by processing steps, since high pressure can be applied to malting, mashing, boiling, filtration and pasteurization. Therefore, the beer processed with high-pressure processing may have an extended shelf-life because this process can inactivate beer spoilage microorganisms and result in a superior sensory quality related to freshness and preservation of flavors as it does to juices that are already commercialized. However, beyond this application, high-pressure processing can modify protein structures, such as enzymes that are present in the malt, like α- and β-amylases. This process can activate enzymes to promote, for example, saccharification, or instead inactivate at the end of mashing, depending on the pressure the product is submitted, besides being capable of isomerizing hops to raise beer bitterness

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

    Indian Academy of Sciences (India)

    Metal azides are well-known for their explosive properties such as detonation or deflagration. As chemically pure sources of nitrogen, alkali metal azides under high pressure have the ability to form polymeric nitrogen, an ultimate green high energy density material with energy density three times greater than that of known ...

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

    Indian Academy of Sciences (India)

    Abstract. Metal azides are well-known for their explosive properties such as detonation or deflagration. As chemically pure sources of nitrogen, alkali metal azides under high pressure have the ability to form polymeric nitrogen, an ultimate green high energy density material with energy density three times greater than that ...

  11. Screening of hydrogen storage media applying high pressure thermogravimetry

    DEFF Research Database (Denmark)

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

    2001-01-01

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

  12. Strawberry pectin methylesterase (PME): purification, characterization, thermal and high-pressure inactivation.

    Science.gov (United States)

    Ly-Nguyen, Binh; Van Loey, Ann M; Fachin, Diana; Verlent, Isabel; Duvetter, Thomas; Vu, Son T; Smout, Chantal; Hendrickx, Marc E

    2002-01-01

    Pectin methylesterase (PME) was extracted from strawberries (Fragaria ananassa, cv Elsanta) and purified by affinity chromatography on a CNBr-Sepharose 4B-PME-inhibitor column. A single protein and PME activity peak was obtained. A biochemical characterization in terms of molecular mass, pI, and kinetic parameters of strawberry PME was performed. In a second step, the thermal and high-pressure stability of the enzyme was studied. Isothermal and combined isothermal-isobaric inactivation of purified strawberry PME could be described by a fractional-conversion model. Purified strawberry PME is much more stable toward high-pressure treatments in comparison to those from oranges and bananas.

  13. Soft x-ray spectroscopy of high pressure liquid

    Science.gov (United States)

    Qiao, Ruimin; Xia, Yujian; Feng, Xuefei; Macdougall, James; Pepper, John; Armitage, Kevin; Borsos, Jason; Knauss, Kevin G.; Lee, Namhey; Allézy, Arnaud; Gilbert, Benjamin; MacDowell, Alastair A.; Liu, Yi-Sheng; Glans, Per-Anders; Sun, Xuhui; Chao, Weilun; Guo, Jinghua

    2018-01-01

    We describe a new experimental technique that allows for soft x-ray spectroscopy studies (˜100-1000 eV) of high pressure liquid (˜100 bars). We achieve this through a liquid cell with a 100 nm-thick Si3N4 membrane window, which is sandwiched by two identical O-rings for vacuum sealing. The thin Si3N4 membrane allows soft x-rays to penetrate, while separating the high-pressure liquid under investigation from the vacuum required for soft x-ray transmission and detection. The burst pressure of the Si3N4 membrane increases with decreasing size and more specifically is inversely proportional to the side length of the square window. It also increases proportionally with the membrane thickness. Pressures > 60 bars could be achieved for 100 nm-thick square Si3N4 windows that are smaller than 65 μm. However, above a certain pressure, the failure of the Si wafer becomes the limiting factor. The failure pressure of the Si wafer is sensitive to the wafer thickness. Moreover, the deformation of the Si3N4 membrane is quantified using vertical scanning interferometry. As an example of the performance of the high-pressure liquid cell optimized for total-fluorescence detected soft x-ray absorption spectroscopy (sXAS), the sXAS spectra at the Ca L edge (˜350 eV) of a CaCl2 aqueous solution are collected under different pressures up to 41 bars.

  14. High-pressure phase transitions of deep earth materials

    International Nuclear Information System (INIS)

    Hirose, Kei

    2009-01-01

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

  15. Ultra-high pressure water jet: Baseline report

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1997-07-31

    The ultra-high pressure waterjet technology was being evaluated at Florida International University (FIU) as a baseline technology. In conjunction with FIU`s evaluation of efficiency and cost, this report covers the evaluation conducted for safety and health issues. It is a commercially available technology and has been used for various projects at locations throughout the country. The ultra-high pressure waterjet technology acts as a cutting tool for the removal of surface substrates. The Husky{trademark} pump feeds water to a lance that directs the high pressure water at the surface to be removed. The safety and health evaluation during the testing demonstration focused on two main areas of exposure. These were dust and noise. The dust exposure was found to be minimal, which would be expected due to the wet environment inherent in the technology, but noise exposure was at a significant level. Further testing for noise is recommended because of the outdoor environment where the testing demonstration took place. In addition, other areas of concern found were arm-hand vibration, ergonomics, heat stress, tripping hazards, electrical hazards, lockout/tagout, fall hazards, slipping hazards, hazards associated with the high pressure water, and hazards associated with air pressure systems.

  16. Releasable, high-pressure seal and method of forming same

    International Nuclear Information System (INIS)

    Holman, R.R.; Turkail, D.N.

    1980-01-01

    An inexpensive releaseable, high-pressure seal was developed, which can withstand pressures over 70 atm, and is particularly useful for nuclear reactors where remote-handling equipment must be used to access the flanged connections. It is smaller than existing high-pressure seals and does not require as many bolts. The fail-safe quality of the seal does not depend on close tolerances or high-quality surface finishes. The seal comprises two conduits through which the high-pressure fluid flows, each fitted with flanges. The second flange has a periphery attached to the second conduit. Each flange has a central opening for the fluid to flow through. The second flange is frustoconical in shape and is resilient so that a portion of it near its central opening can be resiliently biased towards the first flange. A seal ring between the end flanges seals the interior of the conduits from the exterior. A force is applied to the seal ring which acts nearly parallel to the axis of the conduits and varies as a function of the fluid pressure inside of the conduits. The flanges are attached to each other with peripheral collars via a circumferential clamp. (DN)

  17. Ultra-high pressure water jet: Baseline report

    International Nuclear Information System (INIS)

    1997-01-01

    The ultra-high pressure waterjet technology was being evaluated at Florida International University (FIU) as a baseline technology. In conjunction with FIU's evaluation of efficiency and cost, this report covers the evaluation conducted for safety and health issues. It is a commercially available technology and has been used for various projects at locations throughout the country. The ultra-high pressure waterjet technology acts as a cutting tool for the removal of surface substrates. The Husky trademark pump feeds water to a lance that directs the high pressure water at the surface to be removed. The safety and health evaluation during the testing demonstration focused on two main areas of exposure. These were dust and noise. The dust exposure was found to be minimal, which would be expected due to the wet environment inherent in the technology, but noise exposure was at a significant level. Further testing for noise is recommended because of the outdoor environment where the testing demonstration took place. In addition, other areas of concern found were arm-hand vibration, ergonomics, heat stress, tripping hazards, electrical hazards, lockout/tagout, fall hazards, slipping hazards, hazards associated with the high pressure water, and hazards associated with air pressure systems

  18. Single and two-phase flow pressure drop for CANFLEX bundle

    Energy Technology Data Exchange (ETDEWEB)

    Park, Joo Hwan; Jun, Ji Su; Suk, Ho Chun [Korea Atomic Energy Research Institute, Taejon (Korea, Republic of); Dimmick, G. R.; Bullock, D. E. [Atomic Energy of Canada Limited, Ontario (Canada)

    1998-12-31

    Friction factor and two-phase flow frictional multiplier for a CANFLEX bundle are newly developed and presented in this paper. CANFLEX as a 43-element fuel bundle has been developed jointly by AECL/KAERI to provide greater operational flexibility for CANDU reactor operators and designers. Friction factor and two-phase flow frictional multiplier have been developed by using the experimental data of pressure drops obtained from two series of Freon-134a (R-134a) CHF tests with a string of simulated CANFLEX bundles in a single phase and a two-phase flow conditions. The friction factor for a CANFLEX bundle is found to be about 20% higher than that of Blasius for a smooth circular pipe. The pressure drop predicted by using the new correlations of friction factor and two-phase frictional multiplier are well agreed with the experimental pressure drop data of CANFLEX bundle within {+-} 5% error. 11 refs., 5 figs. (Author)

  19. Equation of state of liquid Indium under high pressure

    Directory of Open Access Journals (Sweden)

    Huaming Li

    2015-09-01

    Full Text Available We apply an equation of state of a power law form to liquid Indium to study its thermodynamic properties under high temperature and high pressure. Molar volume of molten indium is calculated along the isothermal line at 710K within good precision as compared with the experimental data in an externally heated diamond anvil cell. Bulk modulus, thermal expansion and internal pressure are obtained for isothermal compression. Other thermodynamic properties are also calculated along the fitted high pressure melting line. While our results suggest that the power law form may be a better choice for the equation of state of liquids, these detailed predictions are yet to be confirmed by further experiment.

  20. Ultra-high pressure water jet: Baseline report; Greenbook (chapter)

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1997-07-31

    The ultra-high pressure waterjet technology was being evaluated at Florida International University (FIU) as a baseline technology. In conjunction with FIU`s evaluation of efficiency and cost, this report covers the evaluation conducted for safety and health issues. It is a commercially available technology and has been used for various projects at locations throughout the country. The ultra-high pressure waterjet technology acts as a cutting tool for the removal of surface substrates. The Husky{trademark} pump feeds water to a lance that directs the high pressure water at the surface to be removed. The technologies being tested for concrete decontamination are targeted for alpha contamination. The safety and health evaluation during the human factors assessment focused on two main areas: noise and dust.

  1. Diagnostics and modeling of high pressure streamer induced discharges

    International Nuclear Information System (INIS)

    Marode, E.; Dessante, P.; Deschamps, N.; Deniset, C.

    2001-01-01

    A great variety of diagnostic has been applied to gain information on basic parameter governing high pressure nonthermal filamentary plasmas (and namely streamer induced filamentary discharges). Apart from electrical diagnostics, gas discharge, in contrast with solid state physics, can greatly benefit from all optical techniques owing to its ''transparent'' state. Emission and absorption spectroscopy, as well as LIF or CARS (talk are given during this meeting on these two techniques) are among such specific possibilities. The figures gained from these diagnostic measurements has generally no meaning by itself. They must be worked out, by means of calibrated former results, and/or by using them as input in high pressure plasma modeling. Mixing experimental and modeling approach is necessary for reaching relevant physical knowledge of the high pressure filamentary discharges processes. It is shown that diffusion, and thermal space and time distribution, must fully be taken into account

  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. A high-pressure bi-directional cycloid rotor flowmeter.

    Science.gov (United States)

    Liu, Shuo; Ding, Fan; Ding, Chuan; Man, Zaipeng

    2014-08-21

    The measurement of the flow rate of various liquids and gases is critical in industrial automation. Rotary positive displacement meters (rotary PD meters) are highly accurate flowmeters that are widely employed in engineering applications, especially in custody transfer operations and hydraulic control systems. This paper presents a high pressure rotary PD meter containing a pair of internal cycloid rotors. It has the advantages of concise structure, low pressure loss, high accuracy and low noise. The curve of the internal rotor is designed as an equidistant curtate epicycloid curve with the external rotor curve as its conjugate. The calculation method used to determine the displacement of the cycloid rotor flowmeter is discussed. A prototype was fabricated, and experiments were performed to confirm measurements over a flow range of 1-100 L/min with relative errors of less than ±0.5%. The pressure loss through the flowmeter was about 3 bar at a flow rate of 100 L/min.

  4. Ultra-high pressure water jet: Baseline report; Greenbook (chapter)

    International Nuclear Information System (INIS)

    1997-01-01

    The ultra-high pressure waterjet technology was being evaluated at Florida International University (FIU) as a baseline technology. In conjunction with FIU's evaluation of efficiency and cost, this report covers the evaluation conducted for safety and health issues. It is a commercially available technology and has been used for various projects at locations throughout the country. The ultra-high pressure waterjet technology acts as a cutting tool for the removal of surface substrates. The Husky trademark pump feeds water to a lance that directs the high pressure water at the surface to be removed. The technologies being tested for concrete decontamination are targeted for alpha contamination. The safety and health evaluation during the human factors assessment focused on two main areas: noise and dust

  5. NATO Advanced Study Institute on High-Pressure Crystallography

    CERN Document Server

    Boldyreva, Elena; High-Pressure Crystallography

    2010-01-01

    This book is devoted to the theme of crystallographic studies at high pressure, with emphasis on the phenomena characteristic to the compressed state of matter, as well as experimental and theoretical techniques used to study these phenomena. As a thermodynamic parameter, pressure is remarkable in many ways. In the visible universe its value spans over sixty orders of magnitude, from the non-equilibrium pressure of hydrogen in intergalactic space, to the kind of pressure encountered within neutron stars. In the laboratory, it provides the unique possibility to control the structure and properties of materials, to dramatically alter electronic properties, and to break existing, or form new chemical bonds. This agenda naturally encompasses elements of physics (properties, structure and transformations), chemistry (reactions, transport), materials science (new materials) and engineering (mechanical properties); in addition it has direct applications and implications for geology (minerals in deep Earth environmen...

  6. Oscillatory high hydrostatic pressure inactivation of Zygosaccharomyces bailii.

    Science.gov (United States)

    Palou, E; López-Malo, A; Barbosa-Cánovas, G V; Welti-Chanes, J; Swanson, B G

    1998-09-01

    Zygosaccharomyces bailii inactivation was evaluated in oscillatory high hydrostatic pressure (HHP) treatments at sublethal pressures (207, 241, or 276 MPa) and compared with continuous HHP treatments in laboratory model systems with a water activity (aw) of 0.98 and pH 3.5. The yeast was inoculated into laboratory model systems and subjected to HHP in sterile bags. Two HHP treatments were conducted: continuous (holding times of 5, 10, 15, 20, 30, 60, or 90 min) and oscillatory (two, three, or four cycles with holding times of 5 min and two cycles with holding times of 10 min). Oscillatory pressure treatments increased the effectiveness of HHP processing. For equal holding times, Z. bailii counts decreased as the number of cycles increased. Holding times of 20 min in HHP oscillatory treatments at 276 MPa assured inactivation (bailii initial inoculum. Oscillatory pressurization could be useful to decrease Z. bailii inactivation time.

  7. High-pressure Raman spectroscopy of phase change materials

    Energy Technology Data Exchange (ETDEWEB)

    Hsieh, Wen-Pin, E-mail: wphsieh@stanford.edu; Mao, Wendy L. [SLAC National Accelerator Laboratory, Stanford Institute for Materials and Energy Sciences, Menlo Park, California 94025 (United States); Department of Geological and Environmental Sciences, Stanford University, Stanford, California 94305 (United States); Zalden, Peter [SLAC National Accelerator Laboratory, Stanford Institute for Materials and Energy Sciences, Menlo Park, California 94025 (United States); Wuttig, Matthias [I. Physikalisches Institut (IA), RWTH Aachen University, 52056 Aachen (Germany); JARA – Fundamentals of Future Information Technology, RWTH Aachen University, 52056 Aachen (Germany); Lindenberg, Aaron M. [SLAC National Accelerator Laboratory, Stanford Institute for Materials and Energy Sciences, Menlo Park, California 94025 (United States); Department of Materials Science and Engineering, Stanford University, Stanford, California 94305 (United States); SLAC National Accelerator Laboratory, PULSE Institute, Menlo Park, California 94025 (United States)

    2013-11-04

    We used high-pressure Raman spectroscopy to study the evolution of vibrational frequencies of the phase change materials (PCMs) Ge{sub 2}Sb{sub 2}Te{sub 5}, GeSb{sub 2}Te{sub 4}, and SnSb{sub 2}Te{sub 4}. We found that the critical pressure for triggering amorphization in the PCMs decreases with increasing vacancy concentration, demonstrating that the presence of vacancies, rather than differences in the atomic covalent radii, is crucial for pressure-induced amorphization in PCMs. Compared to the as-deposited amorphous phase, the pressure-induced amorphous phase has a similar vibrational spectrum but requires much lower laser power to transform into the crystalline phase, suggesting different kinetics of crystallization, which may have implications for applications of PCMs in non-volatile data storage.

  8. Microhole High-Pressure Jet Drill for Coiled Tubing

    Energy Technology Data Exchange (ETDEWEB)

    Ken Theimer; Jack Kolle

    2007-06-30

    Tempress Small Mechanically-Assisted High-Pressure Waterjet Drilling Tool project centered on the development of a downhole intensifier (DHI) to boost the hydraulic pressure available from conventional coiled tubing to the level required for high-pressure jet erosion of rock. We reviewed two techniques for implementing this technology (1) pure high-pressure jet drilling and (2) mechanically-assisted jet drilling. Due to the difficulties associated with modifying a downhole motor for mechanically-assisted jet drilling, it was determined that the pure high-pressure jet drilling tool was the best candidate for development and commercialization. It was also determined that this tool needs to run on commingled nitrogen and water to provide adequate downhole differential pressure and to facilitate controlled pressure drilling and descaling applications in low pressure wells. The resulting Microhole jet drilling bottomhole assembly (BHA) drills a 3.625-inch diameter hole with 2-inch coil tubing. The BHA consists of a self-rotating multi-nozzle drilling head, a high-pressure rotary seal/bearing section, an intensifier and a gas separator. Commingled nitrogen and water are separated into two streams in the gas separator. The water stream is pressurized to 3 times the inlet pressure by the downhole intensifier and discharged through nozzles in the drilling head. The energy in the gas-rich stream is used to power the intensifier. Gas-rich exhaust from the intensifier is conducted to the nozzle head where it is used to shroud the jets, increasing their effective range. The prototype BHA was tested at operational pressures and flows in a test chamber and on the end of conventional coiled tubing in a test well. During instrumented runs at downhole conditions, the BHA developed downhole differential pressures of 74 MPa (11,000 psi, median) and 90 MPa (13,000 psi, peaks). The median output differential pressure was nearly 3 times the input differential pressure available from the

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

    Science.gov (United States)

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

    2007-12-01

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

  10. High-pressure hydrogen materials compatibility of piezoelectric films

    Science.gov (United States)

    Alvine, K. J.; Shutthanandan, V.; Bennett, W. D.; Bonham, C. C.; Skorski, D.; Pitman, S. G.; Dahl, M. E.; Henager, C. H.

    2010-11-01

    Hydrogen is well known for materials compatibility issues, including blistering and embrittlement in metals, which are challenges for its use as the next-generation "green" fuel. Beyond metals, hydrogen also degrades piezoelectric materials used as actuators used in direct injection hydrogen internal combustion engines. We present the materials compatibility studies of piezoelectric films in high-pressure hydrogen environments. Absorption of high-pressure hydrogen and composition changes were studied with an elastic recoil detection analysis and Rutherford back-scattering spectrometry in lead zirconate titanate and barium titanate thin films. Hydrogen surface degradation in the form of blistering and Pb mixing was also observed.

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

    International Nuclear Information System (INIS)

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

    1982-12-01

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

  12. Advanced Decontamination Technologies: High Hydrostatic Pressure on Meat Products

    Science.gov (United States)

    Garriga, Margarita; Aymerich, Teresa

    The increasing demand for “natural” foodstuffs, free from chemical additives, and preservatives has triggered novel approaches in food technology developments. In the last decade, practical use of high-pressure processing (HPP) made this emerging non-thermal technology very attractive from a commercial point of view. Despite the fact that the investment is still high, the resulting value-added products, with an extended and safe shelf-life, will fulfil the wishes of consumers who prefer preservative-free minimally processed foods, retaining sensorial characteristics of freshness. Moreover, unlike thermal treatment, pressure treatment is not time/mass dependant, thus reducing the time of processing.

  13. Thermal and high pressure inactivation kinetics of blueberry peroxidase.

    Science.gov (United States)

    Terefe, Netsanet Shiferaw; Delon, Antoine; Versteeg, Cornelis

    2017-10-01

    This study for the first time investigated the stability and inactivation kinetics of blueberry peroxidase in model systems (McIlvaine buffer, pH=3.6, the typical pH of blueberry juice) during thermal (40-80°C) and combined high pressure-thermal processing (0.1-690MPa, 30-90°C). At 70-80°C, the thermal inactivation kinetics was best described by a biphasic model with ∼61% labile and ∼39% stable fractions at temperature between 70 and 75°C. High pressure inhibited the inactivation of the enzyme with no inactivation at pressures as high as 690MPa and temperatures less than 50°C. The inactivation kinetics of the enzyme at 60-70°C, and pressures higher than 500MPa was best described by a first order biphasic model with ∼25% labile fraction and 75% stable fraction. The activation energy values at atmospheric pressure were 548.6kJ/mol and 324.5kJ/mol respectively for the stable and the labile fractions. Crown Copyright © 2017. Published by Elsevier Ltd. All rights reserved.

  14. Chagas disease, a risk factor for high blood pressure.

    Science.gov (United States)

    Vicco, Miguel Hernán; Rodeles, Luz; Yódice, Agustina; Marcipar, Iván

    2014-12-01

    Chagas disease is a parasite infection caused by the protozoan Trypanosoma cruzi. Its most common complications is chronic Chagas heart disease but impairments of the systemic vasculature also has been observed. Although the different mechanisms that regulate blood pressure are disrupted, to our knowledge data on the association of hypertension and chronic Chagas disease are scarce. In this regard we evaluate whether Chagas disease constitutes a high blood pressure risk factor. We recruited 200 individuals, half of them with positive serology for T. cruzi. They were subjected to a complete clinical examination. The mean age of sampled individuals was 46.7 ± 12.3, and the mean of systolic and diastolic blood pressure were 124 ± 12 mmHg and 82 ± 10 mmHg, respectively. There were no between-group differences regarding age, sex distribution or body mass index. Chagas disease contributed significantly to high blood pressure (OR = 4, 95% CI 1.8323-7.0864, p = 0.0002). Our results reveal an important association between Chagas disease and high blood pressure, which should be contemplated by physicians in order to promote preventive cardiovascular actions in patients with Chagas disease.

  15. 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.)

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

    CERN Document Server

    Nemchinsky, V A

    2003-01-01

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

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

    NARCIS (Netherlands)

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

    2011-01-01

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

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

    Science.gov (United States)

    Oleszczak, P.; Wolanski, P.

    2010-12-01

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

  19. 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)

  20. High blood pressure: prevalence and adherence to guidelines in a population-based cohort.

    Science.gov (United States)

    Walther, Diana; Curjuric, Ivan; Dratva, Julia; Schaffner, Emmanuel; Quinto, Carlos; Rochat, Thierry; Gaspoz, Jean-Michel; Burdet, Luc; Bridevaux, Pierre-Olivier; Pons, Marco; Gerbase, Margaret W; Schindler, Christian; Probst-Hensch, Nicole

    2016-01-01

    High blood pressure, the single leading health risk factor worldwide, contributes greatly to morbidity and mortality. This study aimed to add to the understanding of diagnosed and undiagnosed high blood pressure in Switzerland and to evaluate adherence to hypertension guidelines. Included were 3962 participants from the first (2001-2003) and second (2010-2011) follow-ups of the population-based Swiss Cohort Study on Air Pollution and Lung and Heart Disease in Adults. High blood pressure was defined as blood pressure ≥140/90 mm Hg and the prevalence of doctor-diagnosed hypertension was based on questionnaire information. High blood pressure was found in 34.9% of subjects, 49.1% of whom were unaware of this condition; 30.0% had doctor-diagnosed hypertension and, although 82.1% of these received drug treatments, in only 40.8% was blood pressure controlled (<140/90 mm Hg). Substantial first-line beta-blocker use and nonadherence to comorbidity-specific prescription guidelines were observed and remained mostly unexplained. Age-adjusted rates of unawareness and uncontrolled hypertension were more than 20% higher than in the USA. There is room for improvement in managing hypertension in Switzerland. Population-based observational studies are essential for identifying and evaluating unmet needs in healthcare; however, to pinpoint the underlying causes it is imperative to facilitate linkage of cohort data to medical records.

  1. Vascular effects of a single high salt meal

    Directory of Open Access Journals (Sweden)

    Mohamed Abdel Kader Abdel Wahab

    2016-09-01

    Conclusion: High salt intake may acutely impair vascular function in different vascular beds independent of the increase of blood pressure. Plasma sodium increase may be one of the underlying mechanisms.

  2. ASSERT validation against the Stern Laboratories' single-phase pressure drop tests

    International Nuclear Information System (INIS)

    Waddington, G.M.; Kiteley, J.C.; Carver, M.B.

    1995-01-01

    This paper describes the preliminary validation of ASSERT-IV against the single-phase pressure drop tests from the 37-element CHF (critical heat flux) experiments conducted at Stern Laboratories, and shows how this study fits into the overall ASSERT validation plan. The effects on the pressure drop of several friction and form loss models are evaluated, including the geometry-based K-factor model. The choice of friction factor has a small effect on the predicted channel pressure drop, compared to the form loss model choice. Using the uniform K-factors of Hameed, the computed pressure drops are in excellent agreement with the experimental results from the nominal pressure tube tests. For future ASSERT applications, either Hameed's uniform K-factors or the geometry-based model using Idelchik's thick-edged orifice equation are recommended, as are the friction factor correlations of Colebrook-White, Selander, and Aly and Groeneveld. More analysis of the geometry-based K-factor model is required. (author). 23 refs., 4 tabs., 9 figs

  3. Pressure Drop Correlations of Single-Phase and Two-Phase Flow in Rolling Tubes

    International Nuclear Information System (INIS)

    Xia-xin Cao; Chang-qi Yan; Pu-zhen Gao; Zhong-ning Sun

    2006-01-01

    A series of experimental studies of frictional pressure drop for single phase and two-phase bubble flow in smooth rolling tubes were carried out. The tube inside diameters were 15 mm, 25 mm and 34.5 mm respectively, the rolling angles of tubes could be set as 10 deg. and 20 deg., and the rolling periods could be set as 5 s, 10 s and 15 s. Combining with the analysis of single-phase water motion, it was found that the traditional correlations for calculating single-phase frictional coefficient were not suitable for the rolling condition. Based on the experimental data, a new correlation for calculating single-phase frictional coefficient under rolling condition was presented, and the calculations not only agreed well with the experimental data, but also could display the periodically dynamic characteristics of frictional coefficients. Applying the new correlation to homogeneous flow model, two-phase frictional pressure drop of bubble flow in rolling tubes could be calculated, the results showed that the relative error between calculation and experimental data was less than ± 25%. (authors)

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

    Science.gov (United States)

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

    2017-08-01

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

  5. Phase diagram of Nitrogen at high pressures and temperatures

    Science.gov (United States)

    Jenei, Zsolt; Lin, Jung-Fu; Yoo, Choong-Shik

    2007-03-01

    Nitrogen is a typical molecular solid with relatively weak van der Waals intermolecular interactions but strong intramolecular interaction arising from the second highest binding energy of all diatomic molecules. The phase diagram of solid nitrogen is, however, complicated at high pressures, as inter-molecular interaction becomes comparable to the intra-molecular interaction. In this paper, we present an updated phase diagram of the nitrogen in the pressure-temperature region of 100 GPa and 1000 K, based on in-situ Raman and synchrotron x-ray diffraction studies using externally heated membrane diamond anvil cells. While providing an extension of the phase diagram, our results indicate a ``steeper'' slope of the δ/ɛ phase boundary than previously determined^1. We also studied the stability of the ɛ phase at high pressures and temperatures. Our new experimental results improve the understanding of the Nitrogen phase diagram. 1. Gregoryanz et al, Phys. Rev. B 66, 224108 (2002)

  6. First principles centroid molecular dynamics simulation of high pressure ices

    Science.gov (United States)

    Ikeda, Takashi

    2018-03-01

    The nuclear quantum effects (NQEs) on the structural, elastic, electronic, and vibrational properties of high pressure ices (HPIs) VIII, VII, and X at 270 K were investigated via first principles centroid molecular dynamics (CMD). Our simulations clearly show that even at relatively high temperature of 270 K, the NQEs play a definite role in the pressure-induced proton order (ice VIII)-disorder (ice VII) transition occurring at ˜30 GPa in our H2O ice and the subsequent transition to the symmetric phase ice X suggested to occur at ˜80 GPa. The internal pressure computed at constant NVT conditions shows that the NQEs manifest themselves in the equation of state of HPIs. Our employed approach based on first principles CMD for computing vibrational spectra is proved to be able to reproduce well the overall features of the measured infrared and Raman spectra.

  7. A high-pressure cell for neutron crystal spectrometry

    International Nuclear Information System (INIS)

    Buras, B.; Kofoed, W.; Lebech, B.; Baeckstroem, G.

    1977-04-01

    Three fixed-scattering-angle methods for neutron scattering powder measurements using double- and triple-axis crystal spectrometers were tested: (1) the analyzer-scan method (AS), (2) the monochromator-scan method (MS), and (3) the monochromator-analyzer scan method (MAS). A high-pressure cell, primarily for use in powder diffraction measurements, with scattering angles of 30 0 , 60 0 , 90 0 and 120 0 and a sample volume of about 0.8 cm 3 was constructed and used in conjunction with the MS and MAS methods. At room temperature, this cell makes it possible to make measurements at pressures up to about 40 kbar and up to about 30 kbar at 300 0 C. The report includes a description of the diffraction methods and of the high-pressure cell. A few examples of experimental results are also given. (Auth.)

  8. Ultra-high pressure water jet: Baseline report; Summary

    International Nuclear Information System (INIS)

    1997-01-01

    The Husky trademark is an ultra high pressure waterjet cutting tool system. The pump is mounted on a steel tube frame which includes slots for transport by a forklift. The Husky trademark features an automatic shutdown for several conditions such as low oil pressure and high oil temperature. Placement of the Husky trademark must allow for a three foot clearance on all sides for operation and service access. At maximum continuous operation, the output volume is 7.2 gallons per minute with an output pressure of 40,000 psi. A diesel engine provides power for the system. The safety and health evaluation during the human factors assessment focused on two main areas: noise and dust

  9. Thermal-Hydraulics analysis of pressurized water reactor core by using single heated channel model

    Directory of Open Access Journals (Sweden)

    Reza Akbari

    2017-08-01

    Full Text Available Thermal hydraulics of nuclear reactor as a basis of reactor safety has a very important role in reactor design and control. The thermal-hydraulic analysis provides input data to the reactor-physics analysis, whereas the latter gives information about the distribution of heat sources, which is needed to perform the thermal-hydraulic analysis. In this study single heated channel model as a very fast model for predicting thermal hydraulics behavior of pressurized water reactor core has been developed. For verifying the results of this model, we used RELAP5 code as US nuclear regulatory approved thermal hydraulics code. The results of developed single heated channel model have been checked with RELAP5 results for WWER-1000. This comparison shows the capability of single heated channel model for predicting thermal hydraulics behavior of reactor core.

  10. Investigations on the influence of pressure, current and electrode gap in high-pressure mercury lamps

    International Nuclear Information System (INIS)

    Flesch, P; Neiger, M

    2005-01-01

    This paper is concerned with the numerical simulation of high-intensity discharge lamps, focusing on the influence of pressure, current and electrode gap on plasma, anode and cathode properties. The interaction between electrodes and plasma is taken into account. Comparisons between experimental findings and numerical results show that the observed increase in the total lamp voltage caused by an increasing lamp current is a superposition of an increasing lamp voltage due to an increasing pressure (caused by the increasing lamp current) and a decreasing lamp voltage due to the increasing lamp current (if the pressure would be constant). Furthermore, the numerical results reveal that the plasma potential in the whole plasma strongly depends on the electrode gap and that even the electrode temperature and the arc attachment to the electrodes are influenced by the size of the electrode gap

  11. High Blood Pressure and Chronic Kidney Disease in Children: A Guide for Parents

    Science.gov (United States)

    ... Events Advocacy Donate A to Z Health Guide High Blood Pressure and Kidney Disease in Children Print Email High ... such as the heart and brain. What is high blood pressure? Blood pressure is the force of your blood ...

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

    Science.gov (United States)

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

    2018-01-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2017-11-06

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

  14. A Computer Controlled Precision High Pressure Measuring System

    Science.gov (United States)

    Sadana, S.; Yadav, S.; Jha, N.; Gupta, V. K.; Agarwal, R.; Bandyopadhyay, A. K.; Saxena, T. K.

    2011-01-01

    A microcontroller (AT89C51) based electronics has been designed and developed for high precision calibrator based on Digiquartz pressure transducer (DQPT) for the measurement of high hydrostatic pressure up to 275 MPa. The input signal from DQPT is converted into a square wave form and multiplied through frequency multiplier circuit over 10 times to input frequency. This input frequency is multiplied by a factor of ten using phased lock loop. Octal buffer is used to store the calculated frequency, which in turn is fed to microcontroller AT89C51 interfaced with a liquid crystal display for the display of frequency as well as corresponding pressure in user friendly units. The electronics developed is interfaced with a computer using RS232 for automatic data acquisition, computation and storage. The data is acquired by programming in Visual Basic 6.0. This system is interfaced with the PC to make it a computer controlled system. The system is capable of measuring the frequency up to 4 MHz with a resolution of 0.01 Hz and the pressure up to 275 MPa with a resolution of 0.001 MPa within measurement uncertainty of 0.025%. The details on the hardware of the pressure measuring system, associated electronics, software and calibration are discussed in this paper.

  15. Very Long Single and Few-Walled Boron Nitride Nanotubes via the Pressurized Vapor/Condenser Method

    Science.gov (United States)

    Smith, Michael W.; Jordan, Kevin C.; Park, Cheol; Kim, Jae-Woo; Lillehei, Peter T.; Crooks, Roy; Harrison, Joycelyn S.

    2009-01-01

    A new method for producing long, small diameter, single and few-walled, boron nitride nanotubes (BNNTs) in macroscopic quantities is reported. The pressurized vapor/condenser (PVC) method produces, without catalysts, highly crystalline, very long, small diameter, BNNTs. Palm-sized, cotton-like masses of BNNT raw material were grown by this technique and spun directly into centimeters-long yarn. Nanotube lengths were observed to be 100 times that of those grown by the most closely related method. Self-assembly and growth models for these long BNNTs are discussed.

  16. Very long single- and few-walled boron nitride nanotubes via the pressurized vapor/condenser method

    Energy Technology Data Exchange (ETDEWEB)

    Smith, Michael W. [NASA Langley Research Center, Hampton, VA (United States); Jordan, Kevin C. [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); Park, Cheol [NASA Langley Research Center, Hampton, VA (United States); Kim, Jae-Woo [NASA Langley Research Center, Hampton, VA (United States); Lillehei, Peter T. [NASA Langley Research Center, Hampton, VA (United States); Crooks, Roy [NASA Langley Research Center, Hampton, VA (United States); Harrison, Joycelyn S. [NASA Langley Research Center, Hampton, VA (United States)

    2009-11-01

    Boron nitride nanotubes (BNNTs) are desired for their exceptional mechanical, electronic, thermal, structural, textural, optical, and quantum properties. A new method for producing long, small-diameter, single- and few-walled, boron nitride nanotubes (BNNTs) in macroscopic quantities is reported. The pressurized vapor/condenser (PVC) method produces, without catalysts, highly crystalline, very long, small-diameter, BNNTs. Palm-sized, cotton-like masses of BNNT raw material were grown by this technique and spun directly into centimeters-long yarn. Nanotube lengths were observed to be 100 times that of those grown by the most closely related method. Self-assembly and growth models for these long BNNTs are discussed.

  17. Novel open-framework europium silicates prepared under high-temperature and high-pressure conditions.

    Science.gov (United States)

    Liu, Wei; Ji, Ying; Bao, Xinjian; Wang, Ying; Li, Benxian; Wang, Xiaofeng; Zhao, Xudong; Liu, Xiaoyang; Feng, Shouhua

    2014-10-07

    Two new europium silicates, Na15Eu3Si12O36 (denoted as 1) and K2EuSi4O10F (denoted as 2), were successfully synthesized under high-temperature and high-pressure conditions, and structurally characterized by single-crystal and powder X-ray diffraction (XRD). The single-crystal XRD analysis of 1 reveals that its structure is based on [Si6O18]n(12n-) cyclosilicate anions that are built from six SiO4 tetrahedra sharing two of their four O corners with each other. Such [Si6O18]n(12n-) cyclosilicate anions are linked via EuO6 octahedra to form a three-dimensional (3D) framework containing 6-membered ring channels delimited by the SiO4 tetrahedra and EuO6 octahedra along the [010] direction. The structure of 2 consists of infinite tubular chains of corner-sharing SiO4 tetrahedra, which are further linked together via corner sharing O atoms by infinite chains of EuO4F2 octahedra forming a 3-D framework that contains 8-ring and 6-ring channels along the [010] direction. The photoluminescence properties of 1 and 2 were also investigated.

  18. Feasibility studies for high pressure neutron powder diffraction experiments

    International Nuclear Information System (INIS)

    Von Dreele, R.B.; Parise, J.

    1990-01-01

    We recently performed two neutron powder diffraction experiments on very small samples on the High Intensity Powder Diffractometer (HIPD). These were done to determine the feasibility of performing in situ high pressure/high temperature neutron diffraction experiments on HIPD at pressures which would exceed the previous limit of ∼50 kbar achievable in a neutron diffraction experiment. The first experiment consisted of examining the product from a high pressure preparation done at Stony Brook. The sample, which had been prepared at 65 kbar and 1000 degree C, consisted of a small platinum capsule filled with CaGeO 3 perovskite. The weights of the capsule included 225 mg of platinum and 49 mg of the germanate. A diffraction experiment taking ∼8.6 hrs at a LANSCE proton beam current of ∼53 μA gave peaks of good intensity from both Pt and CaGeO 3 ; we could begin to see them after only 20 min of beam time. The second experiment was to test the possibility of diffraction from a high pressure apparatus. We placed in the HIPD sample position the central assembly from a 100 kbar octahedral press. Four tungsten carbide anvils and a copper block previously pressed to 65 kbar were held in an aluminum frame. The sample consisted of a small bit of nickel foil (175 mg) placed in a 3 mm hole in the copper block. The active sample volume is defined by the gap between the anvils and the length of the sample. A small portion of the copper block is also seen in this arrangement. This is viewed at 90 degree 2Θ through a similar gap between the anvils by 4 1/2 in. x 12 in. 3 He counter tubes. This arrangement simulates the operating conditions of a high pressure run at 100 kbar and takes advantage of the fixed instrument geometry possible in time-of-flight neutron diffraction experiments

  19. Rheology of phase A at high pressure and high temperature

    Science.gov (United States)

    Hilairet, N.; Amiguet, E.; Wang, Y.; Merkel, S.

    2013-12-01

    Subduction zones are locations where a tectonic plate slides and bends under another one. Materials there undergo large and heterogeneous deformations and stresses which are released through seismicity, occasionally. Thus plasticity of minerals filling faults and shear zones is a critical parameter for understanding the stress balance of whole subduction zones. We present a deformation study on a hexagonal hydrous phase that can exist in shear zones within subducting slabs, phase A, after dehydration of serpentine into pyroxene + phase A. Pure phase A samples were synthesized at 11 GPa and ca. 1100K, in the multi-anvil facility in Clermont-Ferrand, France, with N. Bolfan and D. Andrault. Three samples were deformed at 11 GPa confining pressure, and 673K or 973K, using a D-DIA apparatus [1] at 13B-MD at GSE-CARS, APS, in uniaxial shortening up to -0.24 strain and at 5.10-5 s-1. Lattice strains (a proxy for macro-stress), texture and strain were measured in-situ, using synchrotron radiation. Results from lattice strain and texture analysis show a decrease in flow stress and a change in deformation mechanisms with temperature, coherent with the findings in transmission electron microscopy on samples recovered in relaxation experiments from [2]. The slip systems involved during deformation were further analyzed using Visco-Plastic Self-Consistent (VPSC) simulations [3]. The model inputs were known slip systems for hexagonal materials, including the ones observed by [2], with tunable strengths, the strain rate, final strain, and either a random texture or the starting experimental texture. The final experimental textures could be reproduced. The slip systems that had to be activated for matching the experimental texture confirm the observations by [2]: at 673K, the most active slip systems are prismatic and pyramidal, with the requirement of a smaller activity on the basal system, and at 973K the basal system is the main slip system activated. [1] Wang et al, Review for

  20. Warming of olive oil processed by high hydrostatic pressure

    Czech Academy of Sciences Publication Activity Database

    Houška, M.; Kubásek, M.; Strohalm, J.; Landfeld, A.; Kamarád, Jiří

    2004-01-01

    Roč. 24, č. 2 (2004), s. 303-308 ISSN 0895-7959 R&D Projects: GA MZe EP9026 Keywords : olive oil * food processing * high pressure * warming Subject RIV: GM - Food Processing Impact factor: 0.504, year: 2004