WorldWideScience

Sample records for high subcritical pressures

  1. Thermodynamic properties of a high pressure subcritical UF6He gas volume (irradiated by an external source)

    International Nuclear Information System (INIS)

    Sterritt, D.E.; Lalos, G.T.; Schneider, R.T.

    1976-12-01

    A computer simulation study concerning a compressed fissioning UF 6 gas is presented. The compression is to be achieved by a ballistic piston compressor. Data on UF 6 obtained with this compressor were incorporated in the simulation study. As a neutron source to create the fission events in the compressed gas, a fast burst reactor was considered. The conclusion is that it takes a neutron flux in excess of 10 15 n/cm 2 -s to produce measurable increases in pressure and temperature, while a flux in excess of 10 19 n/cm 2 -s would probably damage the compressor

  2. Simulation of primary fuel atomization processes at subcritical pressures.

    Energy Technology Data Exchange (ETDEWEB)

    Arienti, Marco

    2013-06-01

    This report documents results from an LDRD project for the first-principles simulation of the early stages of spray formation (primary atomization). The first part describes a Cartesian embedded-wall method for the calculation of flow internal to a real injector in a fully coupled primary calculation. The second part describes the extension to an all-velocity formulation by introducing a momentum-conservative semi-Lagrangian advection and by adding a compressible term in the Poissons equation. Accompanying the description of the new algorithms are verification tests for simple two-phase problems in the presence of a solid interface; a validation study for a scaled-up multi-hole Diesel injector; and demonstration calculations for the closing and opening transients of a single-hole injector and for the high-pressure injection of liquid fuel at supersonic velocity.

  3. Experimental investigation on flow patterns of RP-3 kerosene under sub-critical and supercritical pressures

    Science.gov (United States)

    Wang, Ning; Zhou, Jin; Pan, Yu; Wang, Hui

    2014-02-01

    Active cooling with endothermic hydrocarbon fuel is proved to be one of the most promising approaches to solve the thermal problem for hypersonic aircraft such as scramjet. The flow patterns of two-phase flow inside the cooling channels have a great influence on the heat transfer characteristics. In this study, phase transition processes of RP-3 kerosene flowing inside a square quartz-glass tube were experimentally investigated. Three distinct phase transition phenomena (liquid-gas two phase flow under sub-critical pressures, critical opalescence under critical pressure, and corrugation under supercritical pressures) were identified. The conventional flow patterns of liquid-gas two phase flow, namely bubble flow, slug flow, churn flow and annular flow are observed under sub-critical pressures. Dense bubble flow and dispersed flow are recognized when pressure is increased towards the critical pressure whilst slug flow, churn flow and annular flow disappear. Under critical pressure, the opalescence phenomenon is observed. Under supercritical pressures, no conventional phase transition characteristics, such as bubbles are observed. But some kind of corrugation appears when RP-3 transfers from liquid to supercritical. The refraction index variation caused by sharp density gradient near the critical temperature is thought to be responsible for this corrugation.

  4. Catalytic subcritical water liquefaction of flax straw for high yield of furfural

    International Nuclear Information System (INIS)

    Harry, Inibehe; Ibrahim, Hussameldin; Thring, Ron; Idem, Raphael

    2014-01-01

    There is substantial interest in the application of biomass as a renewable fuel or for production of chemicals. Flax straw can be converted into valuable chemicals and biofuels via liquefaction in sub-critical water. In this study, the yield of furfural and the kinetics of flax straw liquefaction under sub-critical water conditions were investigated using a high-pressure autoclave reactor. The liquefaction was conducted in the temperature range of 175–325 °C, pressure of 0.1 MPa–8 MPa, retention time in the range of 0 min–120 min, and flax straw mass fraction (w F ) of 5–20 %. Also, the effect of acid catalysts on furfural yield was studied. The kinetic parameters of flax straw liquefaction were determined using nonlinear regression of the experimental data, assuming second-order kinetics. The apparent activation energy was found to be 27.97 kJ mol −1 while the reaction order was 2.0. The optimum condition for furfural yield was at 250 °C, 6.0 MPa, w F of 5% and 0 retention time after reaching set conditions. An acid catalyst was found to selectively favour furfural yield with 40% flax straw conversion. - Highlights: • Flax straw liquefaction in subcritical water. • Creation of a reaction pathway that can be used to optimized furfural production. • Acid catalyst selectively favoured furfural yield with respect to other liquid products. • At the highest process temperature of 325 °C, a carbon conversion of 40% was achieved. • Activation energy and reaction order was 28 kJ/mol and 2.0 respectively

  5. Development of High Flux Isotope Reactor (HFIR) subcriticality monitoring methods

    International Nuclear Information System (INIS)

    Rothrock, R.B.

    1991-01-01

    Use of subcritical source multiplication measurements during refueling has been investigated as a possible replacement for out-of-reactor subcriticality measurements formerly made on fresh HFIR fuel elements at the ORNL Critical Experiment Facility. These measurements have been used in the past for preparation of estimated critical rod positions, and as a partial verification, prior to reactor startup, that the requirements for operational shutdown margin would be met. Results of subcritical count rate data collection during recent HFIR refuelings and supporting calculations are described illustrating the intended measurement method and its expected uncertainty. These results are compared to historical uses of the out-of-reactor core measurements and their accuracy requirements, and a planned in-reactor test is described which will establish the sensitivity of the method and calibrate it for future routine use during HFIR refueling. 2 refs., 1 fig., 2 tabs

  6. High power ring methods and accelerator driven subcritical reactor application

    Energy Technology Data Exchange (ETDEWEB)

    Tahar, Malek Haj [Univ. of Grenoble (France)

    2016-08-07

    High power proton accelerators allow providing, by spallation reaction, the neutron fluxes necessary in the synthesis of fissile material, starting from Uranium 238 or Thorium 232. This is the basis of the concept of sub-critical operation of a reactor, for energy production or nuclear waste transmutation, with the objective of achieving cleaner, safer and more efficient process than today’s technologies allow. Designing, building and operating a proton accelerator in the 500-1000 MeV energy range, CW regime, MW power class still remains a challenge nowadays. There is a limited number of installations at present achieving beam characteristics in that class, e.g., PSI in Villigen, 590 MeV CW beam from a cyclotron, SNS in Oakland, 1 GeV pulsed beam from a linear accelerator, in addition to projects as the ESS in Europe, a 5 MW beam from a linear accelerator. Furthermore, coupling an accelerator to a sub-critical nuclear reactor is a challenging proposition: some of the key issues/requirements are the design of a spallation target to withstand high power densities as well as ensure the safety of the installation. These two domains are the grounds of the PhD work: the focus is on the high power ring methods in the frame of the KURRI FFAG collaboration in Japan: upgrade of the installation towards high intensity is crucial to demonstrate the high beam power capability of FFAG. Thus, modeling of the beam dynamics and benchmarking of different codes was undertaken to validate the simulation results. Experimental results revealed some major losses that need to be understood and eventually overcome. By developing analytical models that account for the field defects, one identified major sources of imperfection in the design of scaling FFAG that explain the important tune variations resulting in the crossing of several betatron resonances. A new formula is derived to compute the tunes and properties established that characterize the effect of the field imperfections on the

  7. Sub-critical crack growth and clad integrity in a PWR reactor pressure vessel

    International Nuclear Information System (INIS)

    Tice, D.R.; Foreman, A.J.E.; Sharples, J.K.

    1987-10-01

    The possibility of in-service growth of sub-critical defects in a PWR reactor pressure vessel to a critical size which could result in vessel failure was addressed in both the 1976 and 1982 reports of the Light Water Reactor Study Group (LWRSG), under the Chairmanship of Dr W Marshall (now Lord Marshall). An addendum to this report was published by UKAEA in April 1987. The section of the addendum dealing with subcritical crack growth and the related issue of integrity of the stainless steel cladding on the inner vessel surface is reproduced in this report. This section of the LWRSG addendum provides a review of the current status of fatigue crack growth and environmentally assisted cracking research for pressure vessel steels in light water reactor environments, as well as a review of developments in crack growth assessment methods. The review concludes that the alternative assessment procedures now being developed give a more realistic prediction of in service crack growth than the ASME Section XI Appendix A fatigue crack growth curves. (author)

  8. Recycling high-performance carbon fiber reinforced polymer composites using sub-critical and supercritical water

    Science.gov (United States)

    Knight, Chase C.

    complete recycling loop. After showing the feasibility and power of this technology, the third phase of the study was focused on the fundamentals on the degradation of highly cross-linked polymer network by sub- and near-critical water. A methodology framework was established to study the apparent kinetics of the degradation of epoxy in sub-critical water. The reaction rate was modeled by a phenomenological rate model of nth order, and the rate constant was modeled by taking into account of the contributions of important physical parameters, e.g., pressure, temperature and dielectric constants. The applicability of the established model to describe the degradation kinetics was confirmed by the validation runs. This model is a suitable starting point to gain the knowledge required for eventual industrial process design. The final phase of this research consisted of a preliminary foray into investigating the economic feasibility of this technology. A process model was designed around a reactor which was sized according to considerations of industrial relevancy. The simulation of the process was done using Aspen Plus, powerful and comprehensive process simulation software. Economic analysis of this pseudo-realistic process suggested that such technology was economically viable and competitive comparing to other recycling technologies. In summary, this dissertation work represents the first comprehensive investigation on recycling aerospace-grade, multilayer woven fabric composites using supercritical and sub-critical water. The fundamental knowledge gained and process technology developed during this research is anticipated to play an important role in advancing this recycling technology toward potential adoption and implementation by the recycling and composite industry.

  9. High order statistical signatures from source-driven measurements of subcritical fissile systems

    International Nuclear Information System (INIS)

    Mattingly, J.K.

    1998-01-01

    This research focuses on the development and application of high order statistical analyses applied to measurements performed with subcritical fissile systems driven by an introduced neutron source. The signatures presented are derived from counting statistics of the introduced source and radiation detectors that observe the response of the fissile system. It is demonstrated that successively higher order counting statistics possess progressively higher sensitivity to reactivity. Consequently, these signatures are more sensitive to changes in the composition, fissile mass, and configuration of the fissile assembly. Furthermore, it is shown that these techniques are capable of distinguishing the response of the fissile system to the introduced source from its response to any internal or inherent sources. This ability combined with the enhanced sensitivity of higher order signatures indicates that these techniques will be of significant utility in a variety of applications. Potential applications include enhanced radiation signature identification of weapons components for nuclear disarmament and safeguards applications and augmented nondestructive analysis of spent nuclear fuel. In general, these techniques expand present capabilities in the analysis of subcritical measurements

  10. The measurement of subcritical reactivity in nuclear reactors by use of a high frequency sine-wave modulated neutron source

    International Nuclear Information System (INIS)

    Guppy, C.B.

    1964-11-01

    In this report the frequency response characteristics for phase and gain of the fundamental reactor mode of the zero power kinetics are given for various subcritical reactivities in a fast reactor and in a thermal reactor. Results, of a study on harmonic effects based on a small zero energy thermal reactor are presented which demonstrate the importance of spatial harmonic effects. A harmonic theory for thermal reactors is developed. A new method of measuring, subcritical reactivity at moderately high frequencies is suggested which circumvents the harmonic problem. It is shown that at high frequencies there is more sensitivity than at low frequencies and that this could lead to an increased range over which subcritical reactivity can be measured. (author)

  11. Conceptual study of high power proton linac for accelerator driven subcritical nuclear power system

    International Nuclear Information System (INIS)

    Yu Qingchang; Ouyang Huafu; Xu Taoguang

    2002-01-01

    As a prior option of the next generation of energy source, the accelerator driven subcritical nuclear power system (ADS) can use efficiently the uranium and thorium resource, transmute the high-level long-lived radioactive wastes and raise nuclear safety. The ADS accelerator should provide the proton beam with tens megawatts. The superconducting linac is a good selection of ADS accelerator because of its high efficiency and low beam loss rate. The ADS accelerator presented by the authors consists of a 5 MeV radio-frequency quadrupole, a 100 MeV independently phased superconducting cavity linac and a 1 GeV elliptical superconducting cavity linac. The accelerating structures and main parameters are determined and the research and development plan is considered

  12. Conceptual study of high power proton linac for accelerator driven subcritical nuclear power system

    CERN Document Server

    Yu Qi; Ouyang Hua Fu; Xu Tao Guang

    2001-01-01

    As a prior option of the next generation of energy source, the accelerator driven subcritical nuclear power system (ADS) can use efficiently the uranium and thorium resource, transmute the high-level long-lived radioactive wastes and raise nuclear safety. The ADS accelerator should provide the proton beam with tens megawatts. The superconducting linac is a good selection of ADS accelerator because of its high efficiency and low beam loss rate. The ADS accelerator presented by the consists of a 5 MeV radio-frequency quadrupole, a 100 MeV independently phased superconducting cavity linac and a 1 GeV elliptical superconducting cavity linac. The accelerating structures and main parameters are determined and the research and development plan is considered

  13. High performance curcumin subcritical water extraction from turmeric (Curcuma longa L.).

    Science.gov (United States)

    Valizadeh Kiamahalleh, Mohammad; Najafpour-Darzi, Ghasem; Rahimnejad, Mostafa; Moghadamnia, Ali Akbar; Valizadeh Kiamahalleh, Meisam

    2016-06-01

    Curcumin is a hydrophobic polyphenolic compound derived from turmeric rhizome, which consists about 2-5% of the total rhizome content and is a more valuable component of turmeric. For reducing the drawbacks of conventional extraction (using organic solvents) of curcumin, the water as a clean solvent was used for extracting curcumin. Subcritical water extraction (SWE) experimental setup was fabricated in a laboratory scale and the influences of some parameters (e.g. extraction temperature, particle size, retention time and pressure) on the yield of extraction were investigated. Optimum extraction conditions such as SWE pressure of 10bar, extractive temperature of 140°C, particle size of 0.71mm and retention time of 14min were defined. The maximum amount of curcumin extracted at the optimum condition was 3.8wt%. The yield of curcumin extraction was more than 76wt% with regards to the maximum possible curcumin content of turmeric, as known to be 5%. The scanning electron microscope (SEM) images from the outer surface of turmeric, before and after extraction, clearly demonstrated the effect of each parameter; changes in porosity and hardness of turmeric that is directly related to the amount of extracted curcumin in process optimization of the extraction parameters. Copyright © 2016 Elsevier B.V. All rights reserved.

  14. 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 ...

  15. 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 ...

  16. High Blood Pressure (Hypertension)

    Science.gov (United States)

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

  17. Hypertension (High Blood Pressure)

    Science.gov (United States)

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

  18. Subcritical crack growth in the ligament between the instrumentation rods of the BBR pressure vessel bottom

    International Nuclear Information System (INIS)

    Marci, G.; Bazant, E.; Kautz, H.R.

    1978-01-01

    A fracture mechanics fatigue analysis is made for an assumed crack emanating from the bore of an instrumentation rod. This assumed crack has partially penetrated the Inconel buttering of the 22 Ni Mo Cr 37 on which the structural Inconel welds are laid. Our analysis shows that the assumed crack could only penetrate 26% of the remaining ligament of the Inconel structural weld as a result of the fatigue crack growth during the entire operating life of the pressure vessel. Therefore a leak caused by a flaw missed during pre-service and in-service non-destructive testing can be excluded. (author)

  19. 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 ...

  20. 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 ...

  1. High blood pressure - infants

    Science.gov (United States)

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

  2. 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, ...

  3. 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...

  4. STUDY OF THE PREPARATION OF SUGAR FROM HIGH-LIGNIN LIGNOCELLULOSE APPLYING SUBCRITICAL WATER AND ENZYMATIC HYDROLYSIS: SYNTHESIS AND CONSUMABLE COST EVALUATION

    Directory of Open Access Journals (Sweden)

    HANNY F. SANGIAN

    2015-05-01

    Full Text Available This study concern sugars hydrolyzed from the high-lignin coconut coir dust using moderate subcritical water (SCW hydrolysis at pressures 20-40 bar for 1 h and to evaluate the consumable costs driver generated. The SCW method produced two products, sugar liquid and solid (SCW-treated substrate. The solid was proceeded to prepare the sugar via enzymatic hydrolysis using pure cellulase. Yield of sugar hydrolyzed from lignocellulose by SCW technique was 0.25 gram sugar/gram cellulose +hemicellulose, or 0.09-gram sugar/gram lignocellulose at 160 °C and 40 bar. While, the maximum yield of sugar liberated enzymatically from SCW-treated solid was 0.35-gram sugar/gram cellulose+hemicellulose, or 0.13-gram sugar/gram SCW-treated solid. It was found that carbon dioxide gas was the highest cost driving in SCW hydrolysis.

  5. PILOT-SCALE SUBCRITICAL WATER REMEDIATION OF POLYCYCLIC AROMATIC HYDROCARBON- AND PESTICIDE-CONTAMINATED SOIL. (R825394)

    Science.gov (United States)

    Subcritical water (hot water under enough pressure to maintain the liquid state) was used to remove polycyclic aromatic hydrocarbons (PAHs) and pesticides from highly contaminated soils. Laboratory-scale (8 g of soil) experiments were used to determine conditions f...

  6. 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

  7. High blood pressure - adults

    Science.gov (United States)

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

  8. Highly Compact Accelerator-Driven Subcritical Assembly for Medical and Industrial Applications

    International Nuclear Information System (INIS)

    Jasmina Vujic; William Kastenberg; Ehud Greenspan; Ka-Ngo Leung

    2006-01-01

    A novel, highly compact, fusion neutron source (CNS) based on a coaxial electrostatic accelerator is under development at the Lawrence Berkeley National Laboratory. This source is designed to generate up to ∼1012 D-D n/s. This source intensity is an order of magnitude too small for Boron Neutron Capture Therapy (BNCT) applications. The objective of this project is to assess the feasibility of using a small, safe and inexpensive subcritical fission assembly to multiply the fusion neutrons by a factor of (ge)30. The overall design objective is to get a treatment time for deep seated rain tumors that does not significantly increase beyond one hour when the effective multiplication factor of the SCM is k eff = 0.98. There are two major parts to this study: the optimization of the Sub-Critical Multiplier (SCM) and the optimization of the Beam Shaping Assembly (BSA), including the reflector for both subsystems. The SCM optimization objective is to maximize the current of neutrons that leak out from the SCM in the direction of the patient, without exceeding the maximum permissible k eff . Minimizing the required uranium inventory is another objective. SCM design variables considered include the uranium enrichment level in the range not exceeding 20% 235U (for proliferation concerns), SCM geometry and dimensions, fuel thickness and moderator thickness. The objective of the BSA optimization is to maximize the tumor dose rate using the optimal SCM while maintaining a tumor-to-normal tissue dose ratio of at least 20 to 12.5 (corresponding to the tumor control dose and to the healthy tissue dose limit). The BSA design variables include its shape, dimensions and composition. The reflector optimization is, in fact, an integral part of the SCM optimization and of the BSA optimization. The reflector design variables are composition and thickness. The study concludes that it is not quite feasible to achieve the project objective. Nevertheless, it appears feasible to develop a

  9. 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 ...

  10. 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.

  11. High Blood Pressure

    Science.gov (United States)

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

  12. High Blood Pressure

    Science.gov (United States)

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

  13. 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

  14. A simple subcritical chromatographic test for an extended ODS high performance liquid chromatography column classification.

    Science.gov (United States)

    Lesellier, Eric; Tchapla, Alain

    2005-12-23

    This paper describes a new test designed in subcritical fluid chromatography (SFC) to compare the commercial C18 stationary phase properties. This test provides, from a single analysis of carotenoid pigments, the absolute hydrophobicity, the silanol activity and the steric separation factor of the ODS stationary phases. Both the choice of the analytical conditions and the validation of the information obtained from the chromatographic measurements are detailed. Correlations of the carotenoid test results with results obtained from other tests (Tanaka, Engelhard, Sander and Wise) performed both in SFC and HPLC are discussed. Two separation factors, calculated from the retention of carotenoid pigments used as probe, allowed to draw a first classification diagram. Columns, which present identical chromatographic behaviors are located in the same area on this diagram. This location can be related to the stationary phase properties: endcapping treatments, bonding density, linkage functionality, specific area or silica pore diameter. From the first classification, eight groups of columns are distinguished. One group of polymer coated silica, three groups of polymeric octadecyl phases, depending on the pore size and the endcapping treatment, and four groups of monomeric stationary phases. An additional classification of the four monomeric groups allows the comparison of these stationary phases inside each group by using the total hydrophobicity. One hundred and twenty-nine columns were analysed by this simple and rapid test, which allows a comparison of columns with the aim of helping along their choice in HPLC.

  15. Deuterium high pressure target

    International Nuclear Information System (INIS)

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

    2001-01-01

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

  16. 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

  17. Fascination at high pressures

    International Nuclear Information System (INIS)

    Chidambaram, R.

    1992-01-01

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

  18. Using anisotropies in prompt fission neutron coincidences to assess the neutron multiplication of highly multiplying subcritical plutonium assemblies

    Energy Technology Data Exchange (ETDEWEB)

    Mueller, J.M., E-mail: jonathan_mueller@ncsu.edu; Mattingly, J.

    2016-07-21

    There is a significant and well-known anisotropy between the prompt neutrons emitted from a single fission event; these neutrons are most likely to be observed at angles near 0° or 180° relative to each other. However, the propagation of this anisotropy through different generations of a fission chain reaction has not been previously studied. We have measured this anisotropy in neutron–neutron coincidences from a subcritical highly-multiplying assembly of plutonium metal. The assembly was a 4.5 kg α-phase plutonium metal sphere composed of 94% {sup 239}Pu and 6% {sup 240}Pu by mass. Data were collected using two EJ-309 liquid scintillators and two EJ-299 plastic scintillators. The angular distribution of neutron–neutron coincidences was measured at 90° and 180° and found to be largely isotropic. Simulations were performed using MCNPX-PoliMi of similar plutonium metal spheres of varying sizes and a correlation between the neutron multiplication of the assembly and the anisotropy of neutron–neutron coincidences was observed. In principle, this correlation could be used to assess the neutron multiplication of an unknown assembly.

  19. High sensitivity isotope analysis with a 252Cf--235U fueled subcritical multiplier and low background photon detector systems

    International Nuclear Information System (INIS)

    Wogman, N.A.; Rieck, H.G. Jr.; Laul, J.C.; MacMurdo, K.W.

    1976-09-01

    A 252 Cf activation analysis facility has been developed for routine multielement analysis of a wide variety of solid and liquid samples. The facility contains six sources of 252 Cf totaling slightly over 100 mg. These sources are placed in a 93 percent 235 U-enriched uranium core which is subcritical with a K effective of 0.985 (multiplication factor of 66). The system produces a thermal flux on the order of 10 +1 neutrons per square centimeter per second. A pneumatic rabbit system permits automatic irradiation, decay, and counting regimes to be performed unattended on the samples. The activated isotopes are analyzed through their photon emissions with state-of-the-art intrinsic Ge detectors, Ge(Li) detectors, and NaI(Tl) multidimensional gamma ray spectrometers. High efficiency (25 percent), low background, anticoincidence shielded Ge(Li) gamma ray detector systems have been constructed to provide the lowest possible background, yet maintain a peak to Compton ratio of greater than 1000 to 1. The multidimensional gamma ray spectrometer systems are composed of 23 cm diameter x 20 cm thick NaI(Tl) crystals surrounded by NaI(Tl) anticoincidence shields. The detection limits for over 65 elements have been determined for this system. Over 40 elements are detectable at the 1 part per million level at a precision of +-10 percent

  20. Cryogenic, Absolute, High Pressure Sensor

    Science.gov (United States)

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

    2001-01-01

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

  1. Cryogenic High Pressure Sensor Module

    Science.gov (United States)

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

    1999-01-01

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

  2. Pressure Dome for High-Pressure Electrolyzer

    Science.gov (United States)

    Norman, Timothy; Schmitt, Edwin

    2012-01-01

    A high-strength, low-weight pressure vessel dome was designed specifically to house a high-pressure [2,000 psi (approx. = 13.8 MPa)] electrolyzer. In operation, the dome is filled with an inert gas pressurized to roughly 100 psi (approx. = 690 kPa) above the high, balanced pressure product oxygen and hydrogen gas streams. The inert gas acts to reduce the clamping load on electrolyzer stack tie bolts since the dome pressure acting axially inward helps offset the outward axial forces from the stack gas pressure. Likewise, radial and circumferential stresses on electrolyzer frames are minimized. Because the dome is operated at a higher pressure than the electrolyzer product gas, any external electrolyzer leak prevents oxygen or hydrogen from leaking into the dome. Instead the affected stack gas stream pressure rises detectably, thereby enabling a system shutdown. All electrical and fluid connections to the stack are made inside the pressure dome and require special plumbing and electrical dome interfaces for this to be accomplished. Further benefits of the dome are that it can act as a containment shield in the unlikely event of a catastrophic failure. Studies indicate that, for a given active area (and hence, cell ID), frame outside diameter must become ever larger to support stresses at higher operating pressures. This can lead to a large footprint and increased costs associated with thicker and/or larger diameter end-plates, tie-rods, and the frames themselves. One solution is to employ rings that fit snugly around the frame. This complicates stack assembly and is sometimes difficult to achieve in practice, as its success is strongly dependent on frame and ring tolerances, gas pressure, and operating temperature. A pressure dome permits an otherwise low-pressure stack to operate at higher pressures without growing the electrolyzer hardware. The pressure dome consists of two machined segments. An O-ring is placed in an O-ring groove in the flange of the bottom

  3. 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.

  4. Common High Blood Pressure Myths

    Science.gov (United States)

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

  5. Medications for High Blood Pressure

    Science.gov (United States)

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

  6. High blood pressure and diet

    Science.gov (United States)

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

  7. Controlling your high blood pressure

    Science.gov (United States)

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

  8. Superconductivity at high pressures

    Energy Technology Data Exchange (ETDEWEB)

    Brandt, N B; Ginzburg, N I

    1969-07-01

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

  9. 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 ...

  10. Subcriticality determination of nuclear reactor

    International Nuclear Information System (INIS)

    Borisenko, V.I.; Goranchuk, V.V.; Sidoruk, N.M.; Volokh, A.F.

    2014-01-01

    In this article the subcriticality determination of nuclear reactor is considered. Emphasized that, despite the requirements of regulatory documents on the subcriticality determination of WWER from the beginning of their operation, so far, this problem has not been solved. The results of subcriticality determination of Rossi-α method of the WWER-M is presented. The possibility of subcriticality determination of WWER is considered. The possibility of subcriticality determination of Rossi-α method with time resolution is of about 100 microseconds is also considered. The possible reasons for the error in subcriticality determination of the reactor are indicated

  11. Solubility of Benzo[a]pyrene and Organic Matter of Soil in Subcritical Water

    Directory of Open Access Journals (Sweden)

    Svetlana Sushkova

    2015-12-01

    Full Text Available A dynamic subcritical water extraction method of benzo[a]pyrene from soils is under consideration. The optimum conditions for benzo[a]pyrene extraction from soil are described including the soil treatment by subcritical water at 250 °C and 100 atm for 30 min. The effectiveness of developed method was determined using the matrix spiking recovery technique. A comparative analysis was made to evaluate the results of benzo[a]pyrene extraction from soils using the subcritical water and organic solvents. The advantages of the subcritical water extraction involve the use of ecologically friendly solvent, a shorter time for the analysis and a higher amount of benzo[a]pyrene extracted from soil (96 %. The influence of subcritical water extraction on soil properties was measured the investigation of the processes occurring within soil under the influence the high temperature and pressure. Under appropriate conditions of the experiment there is the destruction of the soil organic matter while the composition of the soil mineral fraction remains practically unchanged.

  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. Subcritical nuclear assembly

    International Nuclear Information System (INIS)

    Vega C, H. R.

    2014-08-01

    A Subcritical Nuclear Assembly is a device where the nuclear-fission chain reaction is initiated and maintained using an external neutron source. It is a valuable educational and research tool where in a safe way many reactor parameters can be measured. Here, we have used the Wigner-Seitz method in the six-factor formula to calculate the effective multiplication factor of a subcritical nuclear reactor Nuclear Chicago model 9000. This reactor has approximately 2500 kg of natural uranium heterogeneously distributed in slugs. The reactor uses a 239 PuBe neutron source that is located in the center of an hexagonal array. Using Monte Carlo methods, with the MCNP5 code, a three-dimensional model of the subcritical reactor was designed to estimate the effective multiplication factor, the neutron spectra, the total and thermal neutron fluences along the radial and axial axis. With the neutron spectra in two locations outside the reactor the ambient dose equivalent were estimated. (Author)

  14. BRAHMMA - accelerator driven subcritical facility

    International Nuclear Information System (INIS)

    Roy, Tushar; Shukla, Shefali; Shukla, M.; Ray, N.K.; Kashyap, Y.S.; Patel, T.; Gadkari, S.C.

    2017-01-01

    Accelerator Driven Subcritical systems are being studied worldwide for their potential in burning minor actinides and reducing long term radiotoxicity of spent nuclear fuels. In order to pursue the physics studies of Accelerator Driven Subcritical systems, a thermal subcritical assembly BRAHMMA (BeOReflectedAndHDPeModeratedMultiplying Assembly) has been developed at Purnima Labs, BARC. The facility consists of two major components: Subcritical core and Accelerator (DT/ DD Purnima Neutron Generator)

  15. 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)

  16. High Blood Pressure - Multiple Languages

    Science.gov (United States)

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

  17. Fundamentals of high pressure adsorption

    Energy Technology Data Exchange (ETDEWEB)

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

    2009-12-15

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

  18. High pressure phase transformations revisited.

    Science.gov (United States)

    Levitas, Valery I

    2018-04-25

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

  19. 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

  20. Accelerator driven subcritical reactors

    International Nuclear Information System (INIS)

    Salvatores, M.

    2001-01-01

    ADS concepts have been proposed in the last decade for a variety of applications. However, there is a convergence of interest of several countries and laboratories on the application of ADS to transmutation. This applies to plutonium, and/or minor actinides (MA) and long-lived fission products (LLFP). As far as the so-called partitioning and transmutation (PIT) strategies, it was indicated that they can be clarified according to the option taken with respect to Pu and MA, i.e., a) keep Pu and MA together, b) separate Pu from MA. At present several programs are going on ADS: in Japan, USA Europe, where activities in 9 countries are coordinated by a European Technical Working Group (ETWG), and in Russia. As far as the implications for the definition of nuclear data needs, dedicated subcritical cores should have new type of fuels (Pu+MA in different proportions). Proposals are being worked out. For example, composite (such as ceramic-metallic or ceramic-ceramic) fuels are presently under study. The actinide oxide is dispersed in a metallic matrix (Zr, or W or Mo) or in an oxide matrix (e.g., MgO). In these cases, reliable data are required for the matrix materials. As far as coolants, Pb/Bi, Pb, and gas are considered, besides Na. Hard (or very hard) fast neutron spectrum is required. As far as LLFP, transmutation strategies in ADS are proposed. Candidates are 129 I, 99 Tc, 135 Cs, but also 79 Se, 107 Pd, 93 Zr etc. At present, there is no clear option for their transmutation (one needs a high level of thermalized neutrons, support matrixes for target irradiation, isotopic separations, reprocessing techniques, etc.). Finally, ADS transmutation will give rise to fuel cycles, where very active materials will be present. Cm and higher mass isotopes (up to 252 Cf) will be contributors to dose and neutron source strength. This area will deserve attention in future, in order to define the relevant data needs. It is recommended to coordinate work on MA data as a priority

  1. 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

  2. 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.

  3. High Blood Pressure and Women

    Science.gov (United States)

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

  4. 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.

  5. High Pressure Research on Materials

    Indian Academy of Sciences (India)

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

  6. Neutron chain length distributions in subcritical systems

    International Nuclear Information System (INIS)

    Nolen, S.D.; Spriggs, G.

    1999-01-01

    In this paper, the authors present the results of the chain-length distribution as a function of k in subcritical systems. These results were obtained from a point Monte Carlo code and a three-dimensional Monte Carlo code, MC++. Based on these results, they then attempt to explain why several of the common neutron noise techniques, such as the Rossi-α and Feynman's variance-to-mean techniques, are difficult to perform in highly subcritical systems using low-efficiency detectors

  7. Subcritical nuclear assembly

    Energy Technology Data Exchange (ETDEWEB)

    Vega C, H. R., E-mail: fermineutron@yahoo.com [Universidad Autonoma de Zacatecas, Unidad Academica de Estudios Nucleares, Cipres No. 10, Fracc. La Penuela, 98068 Zacatecas (Mexico)

    2014-08-15

    A Subcritical Nuclear Assembly is a device where the nuclear-fission chain reaction is initiated and maintained using an external neutron source. It is a valuable educational and research tool where in a safe way many reactor parameters can be measured. Here, we have used the Wigner-Seitz method in the six-factor formula to calculate the effective multiplication factor of a subcritical nuclear reactor Nuclear Chicago model 9000. This reactor has approximately 2500 kg of natural uranium heterogeneously distributed in slugs. The reactor uses a {sup 239}PuBe neutron source that is located in the center of an hexagonal array. Using Monte Carlo methods, with the MCNP5 code, a three-dimensional model of the subcritical reactor was designed to estimate the effective multiplication factor, the neutron spectra, the total and thermal neutron fluences along the radial and axial axis. With the neutron spectra in two locations outside the reactor the ambient dose equivalent were estimated. (Author)

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

    Science.gov (United States)

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

  9. Terbium oxide at high pressures

    International Nuclear Information System (INIS)

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

    2011-01-01

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

  10. High Pressure Treatment in Foods

    OpenAIRE

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

    2014-01-01

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

  11. Diffuse interfacelets in transcritical flows of propellants into high-pressure combustors

    Science.gov (United States)

    Urzay, Javier; Jofre, Lluis

    2017-11-01

    Rocket engines and new generations of high-power jet engines and diesel engines oftentimes involve the injection of one or more reactants at subcritical temperatures into combustor environments at high pressures, and more particularly, at pressures higher than those corresponding to the critical points of the individual components of the mixture, which typically range from 13 to 50 bars for most propellants. This class of trajectories in the thermodynamic space has been traditionally referred to as transcritical. Under particular conditions often found in hydrocarbon-fueled chemical propulsion systems, and despite the prevailing high pressures, the flow in the combustor may contain regions close to the injector where a diffuse interface is formed in between the fuel and oxidizer streams that is sustained by surface-tension forces as a result of the elevation of the critical pressure of the mixture. This talk describes progress towards modeling these effects in the conservation equations. Funded by the US Department of Energy.

  12. Pressure vessel failure at high internal pressure

    International Nuclear Information System (INIS)

    Laemmer, H.; Ritter, B.

    1995-01-01

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

  13. The investigation of degradation reaction of various saccharides in high temperature and high pressure water

    Science.gov (United States)

    Saito, T.; Noguchi, S.; Matsumoto, T.; Sasaki, M.; Goto, M.

    2008-07-01

    Recently, conversions of polysaccharides included in biomass resources have been studied in order to recover valuable chemicals. Degradation of polysaccharides has been attracted by many researchers, whereas by-products from secondary reactions of the materials have not been studied very well. For the purpose of understanding reaction behavior of various monosaccharides in high-temperature and high-pressure water regions, we investigated reaction pathway and kinetics through reaction experiments of degradation of saccharides in subcritical water. The experiment was conducted by using continuous flow-type micro-reactors. Glucose was used as the starting material. From the experimental results, the conversion of glucose increased with increasing the residence time. The yields of fructose and 1, 6-anhydro-β-D-glucose decreased with increasing the residence time. The yields of organic acids and some aldehydes increased with increasing the residence time.

  14. The investigation of degradation reaction of various saccharides in high temperature and high pressure water

    International Nuclear Information System (INIS)

    Saito, T; Noguchi, S; Matsumoto, T; Sasaki, M; Goto, M

    2008-01-01

    Recently, conversions of polysaccharides included in biomass resources have been studied in order to recover valuable chemicals. Degradation of polysaccharides has been attracted by many researchers, whereas by-products from secondary reactions of the materials have not been studied very well. For the purpose of understanding reaction behavior of various monosaccharides in high-temperature and high-pressure water regions, we investigated reaction pathway and kinetics through reaction experiments of degradation of saccharides in subcritical water. The experiment was conducted by using continuous flow-type micro-reactors. Glucose was used as the starting material. From the experimental results, the conversion of glucose increased with increasing the residence time. The yields of fructose and 1, 6-anhydro-β-D-glucose decreased with increasing the residence time. The yields of organic acids and some aldehydes increased with increasing the residence time

  15. Computer simulation at high pressure

    International Nuclear Information System (INIS)

    Alder, B.J.

    1977-11-01

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

  16. Anxiety: A Cause of High Blood Pressure?

    Science.gov (United States)

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

  17. African Americans and High Blood Pressure

    Science.gov (United States)

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

  18. 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 ...

  19. Subcritical crack growth in a phosphate laser glass

    Energy Technology Data Exchange (ETDEWEB)

    Crichton, S.N.; Tomozawa, M.; Hayden, J.S.; Suratwala, T.I.; Campbell, J.H.

    1999-11-01

    The rate of subcritical crack growth in a metaphosphate Nd-doped laser glass was measured using the double-cleavage-drilled compression (DCDC) method. The crack velocity is reported as a function of stress intensity at temperatures ranging from 296 to 573 K and in nitrogen with water vapor pressures ranging from 40 Pa (0.3 mmHg) to 4.7 x 10{sup 4} Pa (355 mmHg). The measured crack velocities follow region I, II, and III behavior similar to that reported for silicate glasses. A chemical and mass-transport-limited reaction rate model explains the behavior of the data except at high temperatures and high water vapor pressures where crack tip blunting is observed. Blunting is characterized to reinitiate slow crack growth at higher stresses. A dynamic crack tip blunting mechanism is proposed to explain the deviation from the reaction rate model.

  20. High-pressure sodium lamp

    NARCIS (Netherlands)

    1996-01-01

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

  1. Intermolecular Interactions at high pressure

    DEFF Research Database (Denmark)

    Eikeland, Espen Zink

    2016-01-01

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

  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 Treatment in Foods

    Science.gov (United States)

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

    2014-01-01

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

  5. 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.

  6. 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...

  7. Pourbaix diagrams for the iron–water system extended to high-subcritical and low-supercritical conditions

    International Nuclear Information System (INIS)

    Cook, William G.; Olive, Robert P.

    2012-01-01

    Highlights: ► Pourbaix diagrams for iron–water are extended to low-supercritical temperatures. ► Thermodynamic properties for use in R-HKF model re-evaluated. ► Above the critical point, magnetite solubility is between 10 −11 and 10 −10 mol/kg. - Abstract: The supercritical water-cooled reactor (SCWR) is a Generation IV reactor concept that will operate at temperatures and pressures above water’s thermodynamic critical point. Pourbaix diagrams for the iron–water system at temperatures slightly below and above the critical point at 25 MPa have been constructed to aid the evaluation and development of potential construction materials. High temperature data extrapolation was performed using a revised Helgeson–Kirkham–Flowers model and fit to data on magnetite and hematite solubility in high-temperature water. A low-concentration diagram at 350 °C reveals the importance of water chemistry control to avoid transitioning to an active corrosion region.

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

  9. Subcritical Water Extraction of Monosaccharides from Oil Palm Fronds Hemicelluloses

    International Nuclear Information System (INIS)

    Norsyabilah, R.; Hanim, S.S.; Norsuhaila, M.H.; Noraishah, A.K.; Siti Kartina

    2013-01-01

    Oil palm plantations in Malaysia generate more than 36 million tones of pruned and felled oil palm fronds (OPF) and are generally considered as waste. The composition of monosaccharide in oil palm frond can be extracted using hydrothermal treatment for useful applications. The objectives of this study were to quantify the yield of monosaccharides at various reaction conditions; temperature 170 to 200 degree Celsius, pressure from 500 psi to 800 psi, reaction time from 5 to 15 min using subcritical water extraction and to determine the composition of oil palm frond hemicelluloses at optimum condition. The monosaccharides composition of oil palm frond hemicelluloses were analysed using High Performance Liquid Chromatography (HPLC). The highest yield of monosaccharides can be extracted from OPF at temperature of 190 degree Celsius, pressure of 600 psi and 10 min of contact time which is xylose the most abundant composition (11.79 %) followed with arabinose (2.82 %), glucose (0.61 %) and mannose (0.66 %). (author)

  10. Pulsed neutron source based on accelerator-subcritical-assembly

    Energy Technology Data Exchange (ETDEWEB)

    Inoue, Makoto; Noda, Akira; Iwashita, Yoshihisa; Okamoto, Hiromi; Shirai, Toshiyuki [Kyoto Univ., Uji (Japan). Inst. for Chemical Research

    1997-03-01

    A new pulsed neutron source which consists of a 300MeV proton linac and a nuclear fuel subcritical assembly is proposed. The proton linac produces pulsed spallation neutrons, which are multipied by the subcritical assembly. A prototype proton linac that accelerates protons up to 7MeV has been developed and a high energy section of a DAW structure is studied with a power model. Halo formations in high intensity beam are also being studied. (author)

  11. High pressure effects on fruits and vegetables

    OpenAIRE

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

    2016-01-01

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

  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. High pressure effects on fruits and vegetables

    NARCIS (Netherlands)

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

    2016-01-01

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

  14. Sub-criticality monitoring for ADTR trademark control

    International Nuclear Information System (INIS)

    Ashworth, Roger

    2014-01-01

    Following the debut of the Accelerator Driven Thorium Reactor (ADTR trademark) Power Station at ENC 2010 in Barcelona, thorium as a reactor fuel has gained increasing support. The ADTR trademark concept reactor introduced the combination of an accelerator driven system (ADS) with traditional control rod technology, to provide a very high gain novel sub-critical ADS reactor design. The high gain of the system, while significantly reducing the demands on the accelerator design, pushes up operational sub-criticality (k eff ) closer to unity. In this paper we review this design and the progress made since ENC 2010. We compare 2 different methods of measuring the sub-critical neutron multiplication factor as the fuel cycle develops. The paper discusses the most recent work on k eff measurement and the interesting relationship between neutron flux, accelerator current and fuel temperature when using beam pulse methods to determine operational sub-criticality, of which a European patent is being granted. (orig.)

  15. Experimental study on neutronics in bombardment of thick targets by high energy proton beams for accelerator-driven sub-critical system

    CERN Document Server

    Guo Shi Lun; Shi Yong Qian; Shen Qing Biao; Wan Jun Sheng; Brandt, R; Vater, P; Kulakov, B A; Krivopustov, M I; Sosnin, A N

    2002-01-01

    The experimental study on neutronics in the target region of accelerator-driven sub-critical system is carried out by using the high energy accelerator in Joint Institute for Nuclear Research, Dubna, Russia. The experiments with targets U(Pb), Pb and Hg bombarded by 0.533, 1.0, 3.7 and 7.4 GeV proton beams show that the neutron yield ratio of U(Pb) to Hg and Pb to Hg targets is (2.10 +- 0.10) and (1.76 +- 0.33), respectively. Hg target is disadvantageous to U(Pb) and Pb targets to get more neutrons. Neutron yield drops along 20 cm thick targets as the thickness penetrated by protons increases. The lower the energy of protons, the steeper the neutron yield drops. In order to get more uniform field of neutrons in the targets, the energy of protons from accelerators should not be lower than 1 GeV. The spectra of secondary neutrons produced by different energies of protons are similar, but the proportion of neutrons with higher energy gradually increases as the proton energy increases

  16. High Pressure Electrolyzer System Evaluation

    Science.gov (United States)

    Prokopius, Kevin; Coloza, Anthony

    2010-01-01

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

  17. Subcriticality monitoring method for reactor

    International Nuclear Information System (INIS)

    Ueda, Makoto.

    1991-01-01

    The present invention accurately monitors the reactor subcriticality and ensures the critical safety, irrespective of the presence or absence of artificial neutron sources. That is, when the subcriticality is monitored upon reactivity changing operation which causes reactivity change to the reactor during shutdown, neutron monitors are disposed at a plurality of monitoring positions. Then, neutron counting ratio before and after conducting the reactivity changing operation is determined. The subcriticality of the reactor is monitored by the ratio and the state of scattering of the ratio of neutron counting rate between each of the neutron monitors. With such procedures, signals of the neutron monitors are used, the characteristic that the change of the signals depend on the change of the neutron multiplication of the reactor core can be utilized whether artificial neutron sources (external neutron sources) are disposed or not. Accordingly, the subcriticality can be monitored more reliably. (I.S.)

  18. 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.)

  19. High-pressure microhydraulic actuator

    Science.gov (United States)

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

    2008-06-10

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

  20. Nuclear magnetic resonance studies at high pressures

    International Nuclear Information System (INIS)

    Jonas, J.

    1980-01-01

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

  1. DASH diet to lower high blood pressure

    Science.gov (United States)

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

  2. What Is High Blood Pressure Medicine?

    Science.gov (United States)

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

  3. High blood pressure - medicine-related

    Science.gov (United States)

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

  4. High blood pressure and eye disease

    Science.gov (United States)

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

  5. Accelerator driven sub-critical core

    Science.gov (United States)

    McIntyre, Peter M; Sattarov, Akhdiyor

    2015-03-17

    Systems and methods for operating an accelerator driven sub-critical core. In one embodiment, a fission power generator includes a sub-critical core and a plurality of proton beam generators. Each of the proton beam generators is configured to concurrently provide a proton beam into a different area of the sub-critical core. Each proton beam scatters neutrons within the sub-critical core. The plurality of proton beam generators provides aggregate power to the sub-critical core, via the proton beams, to scatter neutrons sufficient to initiate fission in the sub-critical core.

  6. 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.

  7. High-Pressure Lightweight Thrusters

    Science.gov (United States)

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

    2013-01-01

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

  8. Subcritical tests - nuclear weapon testing under the Comprehensive Test Ban Treaty

    International Nuclear Information System (INIS)

    Hoeibraaten, S.

    1998-10-01

    The report discusses possible nuclear weapons related experiments and whether these are permitted under the 1996 Comprehensive Test Ban Treaty (CTBT). The term ''subcritical experiments'' as used in the United States includes experiments in which one studies fissile materials (so far only plutonium) under extreme conditions generated by conventional high explosives, and in which a self-sustained chain reaction never develops in the fissile material. The known facts about the American subcritical experiments are presented. There is very little reason to doubt that these experiments were indeed subcritical and therefore permitted under the CTBT. Little is known about the Russian efforts that are being made on subcritical experiments

  9. Evaluation of high temperature pressure sensors

    International Nuclear Information System (INIS)

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

    2011-01-01

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

  10. Study of high-pressure adsorption from supercritical fluids by the potential theory

    DEFF Research Database (Denmark)

    Monsalvo, Matias Alfonso; Shapiro, Alexander

    2009-01-01

    The multicomponent potential theory of adsorption (MPTA), which has been previously used to study low-pressure adsorption of subcritical fluids, is extended to adsorption equilibria from supercritical fluids up to high pressures. The MPTA describes an adsorbed phase as an inhomogeneous fluid...... the adsorbed and the gas phases. We have also evaluated the performance of the classical Soave-Redlich-Kwong (SRK) EoS. The fluid-solid interactions are described by simple Dubinin-Radushkevich-Astakhov (DRA) potentials. In addition, we test the performance of the 10-4-3 Steele potential. It is shown...... that application of sPC-SAFT slightly improves the performance of the MPTA and that in spite of its simplicity, the DRA model can be considered as an accurate potential, especially, for mixture adsorption. We show that, for the sets of experimental data considered in this work, the MPTA is capable of predicting...

  11. Reaction kinetics of cellulose hydrolysis in subcritical and supercritical water

    Science.gov (United States)

    Olanrewaju, Kazeem Bode

    The uncertainties in the continuous supply of fossil fuels from the crisis-ridden oil-rich region of the world is fast shifting focus on the need to utilize cellulosic biomass and develop more efficient technologies for its conversion to fuels and chemicals. One such technology is the rapid degradation of cellulose in supercritical water without the need for an enzyme or inorganic catalyst such as acid. This project focused on the study of reaction kinetics of cellulose hydrolysis in subcritical and supercritical water. Cellulose reactions at hydrothermal conditions can proceed via the homogeneous route involving dissolution and hydrolysis or the heterogeneous path of surface hydrolysis. The work is divided into three main parts. First, the detailed kinetic analysis of cellulose reactions in micro- and tubular reactors was conducted. Reaction kinetics models were applied, and kinetics parameters at both subcritical and supercritical conditions were evaluated. The second major task was the evaluation of yields of water soluble hydrolysates obtained from the hydrolysis of cellulose and starch in hydrothermal reactors. Lastly, changes in molecular weight distribution due to hydrothermolytic degradation of cellulose were investigated. These changes were also simulated based on different modes of scission, and the pattern generated from simulation was compared with the distribution pattern from experiments. For a better understanding of the reaction kinetics of cellulose in subcritical and supercritical water, a series of reactions was conducted in the microreactor. Hydrolysis of cellulose was performed at subcritical temperatures ranging from 270 to 340 °C (tau = 0.40--0.88 s). For the dissolution of cellulose, the reaction was conducted at supercritical temperatures ranging from 375 to 395 °C (tau = 0.27--0.44 s). The operating pressure for the reactions at both subcritical and supercritical conditions was 5000 psig. The results show that the rate-limiting step in

  12. COMPARISONS OF SOXHLET EXTRACTION, PRESSURIZED LIQUID EXTRACTION, SUPERCRITICAL FLUID EXTRACTION, AND SUBCRITICAL WATER EXTRACTION FOR ENVIRONMENTAL SOLIDS: RECOVERY, SELECTIVITY, AND EFFECTS ON SAMPLE MATRIX. (R825394)

    Science.gov (United States)

    Extractions of a polycyclic aromatic hydrocarbon (PAH)-contaminated soil from a former manufactured gas plant site were performed with a Soxhlet apparatus (18 h), by pressurized liquid extraction (PLE) (50 min at 100°C), supercritical fluid extraction (SFE) (1 h at 150°...

  13. HIGH BLOOD PRESSURE: DOES THIS CONCERN ME?

    CERN Multimedia

    2007-01-01

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

  14. HIGH BLOOD PRESSURE: DOES THIS CONCERN ME?

    CERN Multimedia

    2007-01-01

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

  15. Subcritical assemblies, use and their feasibility assessment

    International Nuclear Information System (INIS)

    Haroon, M.R.

    1982-03-01

    In developing countries, subcritical assemblies can be a useful tool for training and research in the field of nuclear technology with minimum cost. The historical development of subcritical assemblies and the reactor physics experiments which can be carried out using this facility are outlined. The different types of subcritical assemblies have been described and material requirements for each assembly have been pointed out. (author)

  16. Criticality Analysis of the U-H2O Subcritical Assembly Modified for Rand D of the High Temperature Reactor

    International Nuclear Information System (INIS)

    Syarip; Tri-Wulan-Tjiptono; Tegas-Sutondo

    2000-01-01

    A criticality analysis of the natural uranium - light water sub-criticalassembly available at the P3TM-BATAN Yogyakarta, converted into a naturaluranium - graphite system has been performed. The purpose of this study is toprovide the research facility on the basic static and kinetics studies forthe high temperature reactor (HTR) in which the HTR fuel system is underdevelopment at the P3TM. For the purpose of this study, a neutroniccalculation was performed using WIMSD/4 code, to determine the neutronmultiplication factor for various fuel configurations of the sub-criticalassemblies. The results show that the effective neutron multiplication factor(k ef ) for U-Be-H 2 O and U-Be-He systems are 1.0474 and 1.4666 respectively,while for the graphite moderated systems with coolants of H 2 O or He(U-C-H 2 O and U-C-He) systems, the corresponding k ef are 0.787 and 0.4211respectively. The results conclude that the modification of U-H 2 O toU-C-H 2 O system, in accordance with neutronic is quite feasible, safe, cheapand practical, and in addition, the treatment of H 2 O is relatively easy.(author)

  17. High pressure effect for high-Tc superconductors

    International Nuclear Information System (INIS)

    Takahashi, Hiroki; Tomita, Takahiro

    2011-01-01

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

  18. Experimental sizing and assessment of two-phase pressure drop correlations for a capillary tube with transcritical and subcritical carbon dioxide flow

    International Nuclear Information System (INIS)

    Trinchieri, R; Boccardi, G; Calabrese, N; Zummo, G; Celata, G P

    2014-01-01

    In the last years, CO 2 was proposed as an alternative refrigerant for different refrigeration applications (automotive air conditioning, heat pumps, refrigerant plants, etc.) In the case of low power refrigeration applications, as a household refrigerator, the use of too expensive components is not economically sustainable; therefore, even if the use of CO 2 as the refrigerant is desired, it is preferable to use conventional components as much as possible. For these reasons, the capillary tube is frequently proposed as expansion system. Then, it is necessary to characterize the capillary in terms of knowledge of the evolving mass flow rate and the associate pressure drop under all possible operative conditions. For this aim, an experimental campaign has been carried out on the ENEA test loop 'CADORE' to measure the performance of three capillary tubes having same inner diameter (0.55 mm) but different lengths (4, 6 and 8 meters). The test range of inlet pressure is between about 60 and 110 bar, whereas external temperatures are between about 20 to 42 °C. The two-phase pressure drop through the capillary tube is detected and experimental values are compared with the predictions obtained with the more widely used correlations available in the literature. Correlations have been tested over a wide range of variation of inlet flow conditions, as a function of different inlet parameters.

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

    International Nuclear Information System (INIS)

    Tachibana, Koji

    1995-01-01

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

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

    International Nuclear Information System (INIS)

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

    2003-01-01

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

  1. Cygnus Performance in Subcritical Experiments

    International Nuclear Information System (INIS)

    G Corrow; M Hansen; D Henderson; S Lutz; C Mitton

    2008-01-01

    The Cygnus Dual Beam Radiographic Facility consists of two identical radiographic sources with the following specifications: 4-rad dose at 1 m, 1-mm spot size, 50-ns pulse length, 2.25-MeV endpoint energy. The facility is located in an underground tunnel complex at the Nevada Test Site. Here SubCritical Experiments (SCEs) are performed to study the dynamic properties of plutonium. The Cygnus sources were developed as a primary diagnostic for these tests. Since SCEs are single-shot, high-value events - reliability and reproducibility are key issues. Enhanced reliability involves minimization of failure modes through design, inspection, and testing. Many unique hardware and operational features were incorporated into Cygnus to insure reliability. Enhanced reproducibility involves normalization of shot-to-shot output also through design, inspection, and testing. The first SCE to utilize Cygnus, Armando, was executed on May 25, 2004. A year later, April - May 2005, calibrations using a plutonium step wedge were performed. The results from this series were used for more precise interpretation of the Armando data. In the period February - May 2007 Cygnus was fielded on Thermos, which is a series of small-sample plutonium shots using a one-dimensional geometry. Pulsed power research generally dictates frequent change in hardware configuration. Conversely, SCE applications have typically required constant machine settings. Therefore, while operating during the past four years we have accumulated a large database for evaluation of machine performance under highly consistent operating conditions. Through analysis of this database Cygnus reliability and reproducibility on Armando, Step Wedge, and Thermos is presented

  2. Cygnus Performance in Subcritical Experiments

    Energy Technology Data Exchange (ETDEWEB)

    G. Corrow, M. Hansen, D. Henderson, S. Lutz, C. Mitton, et al.

    2008-02-01

    The Cygnus Dual Beam Radiographic Facility consists of two identical radiographic sources with the following specifications: 4-rad dose at 1 m, 1-mm spot size, 50-ns pulse length, 2.25-MeV endpoint energy. The facility is located in an underground tunnel complex at the Nevada Test Site. Here SubCritical Experiments (SCEs) are performed to study the dynamic properties of plutonium. The Cygnus sources were developed as a primary diagnostic for these tests. Since SCEs are single-shot, high-value events - reliability and reproducibility are key issues. Enhanced reliability involves minimization of failure modes through design, inspection, and testing. Many unique hardware and operational features were incorporated into Cygnus to insure reliability. Enhanced reproducibility involves normalization of shot-to-shot output also through design, inspection, and testing. The first SCE to utilize Cygnus, Armando, was executed on May 25, 2004. A year later, April - May 2005, calibrations using a plutonium step wedge were performed. The results from this series were used for more precise interpretation of the Armando data. In the period February - May 2007 Cygnus was fielded on Thermos, which is a series of small-sample plutonium shots using a one-dimensional geometry. Pulsed power research generally dictates frequent change in hardware configuration. Conversely, SCE applications have typically required constant machine settings. Therefore, while operating during the past four years we have accumulated a large database for evaluation of machine performance under highly consistent operating conditions. Through analysis of this database Cygnus reliability and reproducibility on Armando, Step Wedge, and Thermos is presented.

  3. High pressure gas reinjection unit

    Energy Technology Data Exchange (ETDEWEB)

    1976-03-01

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

  4. High-pressure boron hydride phases

    International Nuclear Information System (INIS)

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

    1997-01-01

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

  5. Superfluid helium at subcritical active core

    International Nuclear Information System (INIS)

    Vasil'ev, V.V.; Lopatkin, A.V.; Muratov, V.G.; Rakhno, I.L.

    2002-01-01

    Power range and neutron flux wherein super thermal source was realized at high volume of superfluid helium were investigated. MCU, BRAND, MCNP codes were used for the calculation of reactors. It is shown that the availability of full-size diameter for cryogenic source of ultracold neutrons, as the source with superfluid helium is considered, is possible in the reflector of subcritical assembly. Results obtained from the MCNP-4B code application demonstrated that the density of thermal neutron flux in helium must be not higher than 2.3 x 10 11 s -1 cm -2 [ru

  6. High-pressure torsion of hafnium

    International Nuclear Information System (INIS)

    Edalati, Kaveh; Horita, Zenji; Mine, Yoji

    2010-01-01

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

  7. (n,xn cross section measurements for Y-89 foils used as detectors for high energy neutron measurements in the deeply subcritical assembly “QUINTA”

    Directory of Open Access Journals (Sweden)

    Bielewicz Marcin

    2017-01-01

    Full Text Available Study of the deep subcritical systems (QUINTA using relativistic beams is performed within the project “Energy and Transmutation of Radioactive Wastes” (E&T – RAW. The experiment assembly was irradiated by deuteron/proton beam (Dubna NUCLOTRON. We calculated the neutron energy spectrum inside the whole assembly by using threshold energy (n,xn reactions in yttrium (Y-89 foils. There are almost no experimental cross section data for those reactions. New Y-89(n,xn cross section measurements were carried out at The Svedberg laboratory (TSL in Uppsala, Sweden in 2015. In this paper we present preliminary results of those experiments.

  8. High pressure X-ray studies

    International Nuclear Information System (INIS)

    Sikka, S.K.

    1981-01-01

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

  9. Managing Stress to Control High Blood Pressure

    Science.gov (United States)

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

  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 injection of dimethyl ether

    Energy Technology Data Exchange (ETDEWEB)

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

    1997-08-01

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

  12. 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...

  13. 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

  14. High-pressure mechanical instability in rocks.

    Science.gov (United States)

    Byerlee, J D; Brace, W F

    1969-05-09

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

  15. The safe, economical operation of a slightly subcritical reactor and transmutor with a small proton accelerator

    International Nuclear Information System (INIS)

    Takahashi, Hiroshi

    1994-01-01

    I suggest that an accelerator can be used to increase the safety and neutron economy of a power reactor and a transmutor of long-lived radioactive wastes, such as minor actinides and fission products, by providing neutrons for its subcritical operation. Instead of the large subcriticality k=0.9-0.95 which we originally proposed for such transmutor, we propose to use a slightly subcritical reactor, such as k=0.99, which will avoid many of the technical difficulties that are associated with large subcriticality, such as localized power peaking, radiation damage due to injection of medium-energy protons, the high current accelerator, and the requirement for a long beam-expansion section. We analyze the power drop that occurred in Phenix reactor, and show that the operating this reactor in subcritical conditions improves safety. (author). 13 refs., 5 figs

  16. The safe, economical operation of a slightly subcritical reactor and transmutor with a small proton accelerator

    International Nuclear Information System (INIS)

    Takahashi, Hiroshi.

    1994-01-01

    This report describes methods in which an accelerator can be used to increase the safety and neutron economy of a power reactor and transmutor of long-lived radioactive wastes, such as minor actinides and fission products, by providing neutrons for its subcritical operation. Instead of the rather large subcriticality of k=0.9--0.95 which we originally proposed for such a transmutor, we propose to use a slightly subcritical reactor, such as k=0.99, which will avoid many of the technical difficulties that are associated with large subcriticality, such as localized power peaking, radiation damage due to the injection of medium-energy protons, the high current accelerator, and the requirement for a long beam-expansion section. We analyzed the power drop that occurred in Phoenix reactor, and show that the operating this reactor in subcritical condition improves its safety

  17. A microfluidic sub-critical water extraction instrument

    Science.gov (United States)

    Sherrit, Stewart; Noell, Aaron C.; Fisher, Anita; Lee, Mike C.; Takano, Nobuyuki; Bao, Xiaoqi; Kutzer, Thomas C.; Grunthaner, Frank

    2017-11-01

    This article discusses a microfluidic subcritical water extraction (SCWE) chip for autonomous extraction of amino acids from astrobiologically interesting samples. The microfluidic instrument is composed of three major components. These include a mixing chamber where the soil sample is mixed and agitated with the solvent (water), a subcritical water extraction chamber where the sample is sealed with a freeze valve at the chip inlet after a vapor bubble is injected into the inlet channels to ensure the pressure in the chip is in equilibrium with the vapor pressure and the slurry is then heated to ≤200 °C in the SCWE chamber, and a filter or settling chamber where the slurry is pumped to after extraction. The extraction yield of the microfluidic SCWE chip process ranged from 50% compared to acid hydrolysis and 80%-100% compared to a benchtop microwave SCWE for low biomass samples.

  18. Nucleation at high pressure I: Theoretical considerations.

    NARCIS (Netherlands)

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

    1999-01-01

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

  19. 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.

  20. High-pressure oxidation of ethane

    DEFF Research Database (Denmark)

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

    2017-01-01

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

  1. High-pressure phase transitions of strontianite

    Science.gov (United States)

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

    2015-12-01

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

  2. 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

  3. High pressure processing of meat

    DEFF Research Database (Denmark)

    Grossi, Alberto; Christensen, Mette; Ertbjerg, Per

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

  4. Measurement and interpretation of threshold stress intensity factors for steels in high-pressure hydrogen gas.

    Energy Technology Data Exchange (ETDEWEB)

    Dadfarnia, Mohsen (University of Illinois at Urbana-Champaign, Urbana, IL); Nibur, Kevin A.; San Marchi, Christopher W.; Sofronis, Petros (University of Illinois at Urbana-Champaign, Urbana, IL); Somerday, Brian P.; Foulk, James W., III; Hayden, Gary A. (CP Industries, McKeesport, PA)

    2010-07-01

    Threshold stress intensity factors were measured in high-pressure hydrogen gas for a variety of low alloy ferritic steels using both constant crack opening displacement and rising crack opening displacement procedures. The sustained load cracking procedures are generally consistent with those in ASME Article KD-10 of Section VIII Division 3 of the Boiler and Pressure Vessel Code, which was recently published to guide design of high-pressure hydrogen vessels. Three definitions of threshold were established for the two test methods: K{sub THi}* is the maximum applied stress intensity factor for which no crack extension was observed under constant displacement; K{sub THa} is the stress intensity factor at the arrest position for a crack that extended under constant displacement; and K{sub JH} is the stress intensity factor at the onset of crack extension under rising displacement. The apparent crack initiation threshold under constant displacement, K{sub THi}*, and the crack arrest threshold, K{sub THa}, were both found to be non-conservative due to the hydrogen exposure and crack-tip deformation histories associated with typical procedures for sustained-load cracking tests under constant displacement. In contrast, K{sub JH}, which is measured under concurrent rising displacement and hydrogen gas exposure, provides a more conservative hydrogen-assisted fracture threshold that is relevant to structural components in which sub-critical crack extension is driven by internal hydrogen gas pressure.

  5. Raman spectroscopy of triolein under high pressures

    Science.gov (United States)

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

    2010-03-01

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

  6. Concept of turbines for ultrasupercritical, supercritical, and subcritical steam conditions

    Science.gov (United States)

    Mikhailov, V. E.; Khomenok, L. A.; Pichugin, I. I.; Kovalev, I. A.; Bozhko, V. V.; Vladimirskii, O. A.; Zaitsev, I. V.; Kachuriner, Yu. Ya.; Nosovitskii, I. A.; Orlik, V. G.

    2017-11-01

    The article describes the design features of condensing turbines for ultrasupercritical initial steam conditions (USSC) and large-capacity cogeneration turbines for super- and subcritical steam conditions having increased steam extractions for district heating purposes. For improving the efficiency and reliability indicators of USSC turbines, it is proposed to use forced cooling of the head high-temperature thermally stressed parts of the high- and intermediate-pressure rotors, reaction-type blades of the high-pressure cylinder (HPC) and at least the first stages of the intermediate-pressure cylinder (IPC), the double-wall HPC casing with narrow flanges of its horizontal joints, a rigid HPC rotor, an extended system of regenerative steam extractions without using extractions from the HPC flow path, and the low-pressure cylinder's inner casing moving in accordance with the IPC thermal expansions. For cogeneration turbines, it is proposed to shift the upper district heating extraction (or its significant part) to the feedwater pump turbine, which will make it possible to improve the turbine plant efficiency and arrange both district heating extractions in the IPC. In addition, in the case of using a disengaging coupling or precision conical bolts in the coupling, this solution will make it possible to disconnect the LPC in shifting the turbine to operate in the cogeneration mode. The article points out the need to intensify turbine development efforts with the use of modern methods for improving their efficiency and reliability involving, in particular, the use of relatively short 3D blades, last stages fitted with longer rotor blades, evaporation techniques for removing moisture in the last-stage diaphragm, and LPC rotor blades with radial grooves on their leading edges.

  7. 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...

  8. Modeling High Pressure Micro Hollow Cathode Discharges

    National Research Council Canada - National Science Library

    Boeuf, Jean-Pierre; Pitchford, Leanne

    2004-01-01

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

  9. Foaming Glass Using High Pressure Sintering

    DEFF Research Database (Denmark)

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

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

  10. Preeclampsia and High Blood Pressure During Pregnancy

    Science.gov (United States)

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

  11. Teaming Up Against High Blood Pressure

    Centers for Disease Control (CDC) Podcasts

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

  12. Transesterification of soybean oil with methanol and acetic acid at lower reaction severity under subcritical conditions

    International Nuclear Information System (INIS)

    Go, Alchris Woo; Sutanto, Sylviana; NguyenThi, Bich Thuyen; Cabatingan, Luis K.; Ismadji, Suryadi; Ju, Yi-Hsu

    2014-01-01

    Highlights: • (trans)Esterification of oils under subcritical conditions. • Acetic acid as catalyst and co-solvent in biodiesel production. • Influence of reactor hydrodynamic (loading and stirring) on FAME yield. • High methyl ester yield can be obtained at less severe reaction conditions. - Abstract: Soybean oil (56–80 g) was reacted with methanol (40–106 mL) to produce fatty acid methyl ester in the presence of 1–6% acetic acid under subcritical condition at 250 °C. Stirring and loading of the reaction system affected the yield and severity of the process. The presence of acetic acid improved the yield of FAME from 32.1% to 89.5% at a methanol to oil molar ratio of 20 mL/g. Acetic acid was found to act strongly as an acid catalyst and to some extent improved the solubility between oil and methanol. Reaction pressure higher than the supercritical pressure of methanol (7.85 MPa) was not required to achieve high FAME yield (89.5–94.8%) in short time (30–60 min)

  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 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.

  15. 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

  16. 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...

  17. On high-pressure melting of tantalum

    Science.gov (United States)

    Luo, Sheng-Nian; Swift, Damian C.

    2007-01-01

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

  18. Extraction of antioxidants from Chlorella sp. using subcritical water treatment

    Science.gov (United States)

    Zakaria, S. M.; Mustapa Kamal, S. M.; Harun, M. R.; Omar, R.; Siajam, S. I.

    2017-06-01

    Chlorella sp. microalgae is one of the main source of natural bioactive compounds used in the food and pharmaceutical industries. Subcritical water extraction is the technique that offers an efficient, non-toxic, and environmental-friendly method to obtain natural ingredients. In this work, the extracts of Chlorella sp. microalgae was evaluated in terms of: chemical composition, extraction (polysaccharides) yield and antioxidant activity, using subcritical water extraction. Extractions were performed at temperatures ranging from 100°C to 300°C. The results show that by using subcritical water, the highest yield of polysaccharides is 23.6 that obtained at 150°C. Analysis on the polysaccharides yield show that the contents were highly influenced by the extraction temperature. The individual antioxidant activity were evaluated by in vitro assay using a free radical method. In general, the antioxidant activity of the extracts obtained at different water temperatures was high, with values of 31.08-54.29 . The results indicated that extraction by subcritical water was effective and Chlorella sp. can be a useful source of natural antioxidants.

  19. Pressure sensor for high-temperature liquids

    International Nuclear Information System (INIS)

    Forster, G.A.

    1978-01-01

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

  20. 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.

  1. Workshop on Subcritical Neutron Production

    International Nuclear Information System (INIS)

    Walter Sadowski; Roald Sagdeev

    2006-01-01

    Executive Summary of the Workshop on Subcritical Neutron Production A workshop on Subcritical Neutron Production was sponsored by the East-West Center of the University of Maryland on October 11-13, 2004. The subject of the workshop was the application of subcritical neutrons to transmutation of actinides. The workshop was attended by members of the fission, accelerator and fusion communities. Papers on the state of development of neutron production by accelerators, fusion devices, and fission reactors were presented. Discussions were held on the potential of these technologies to solve the problems of spent nuclear waste storage and nuclear non-proliferation presented by current and future nuclear power reactors. A list of participants including their affiliation and their E-Mail addresses is attached. The workshop concluded that the technologies, presently available or under development, hold out the exciting possibility of improving the environmental quality and long term energy resources of nuclear power while strengthening proliferation resistance. The workshop participants agreed on the following statements. The workshop considered a number of technologies to deal with spent nuclear fuels and current actinide inventories. The conclusion was reached that substantial increase in nuclear power production will require that the issue of spent nuclear fuel be resolved. The Workshop concluded that 14 MeV fusion neutrons can be used to destroy nuclear reactor by-products, some of which would otherwise have to be stored for geologic periods of time. The production of 14 MeV neutrons is based on existing fusion technologies at different research institutions in several countries around the world. At the present time this technology is used to produce 14 MeV neutrons in JET. More development work will be required, however, to bring fusion technology to the level where it can be used for actinide burning on an industrial scale. The workshop concluded that the potential

  2. Comparative analysis of sub-critical transmutation reactor concepts

    International Nuclear Information System (INIS)

    Chang, S. H.

    1997-01-01

    The long-lived nuclear wastes have been substantially generated from the light water reactor for a few decades. The toxicity of these spent fuels will be higher than that of the uranium ore, even if those will be stored in the repository more than ten thousands. Hence the means of transmuting the key long-lived nuclear wastes, primarily the minor actinides, using a hybrid proton accelerator and subcritical transmutation reactor, are proposed. Until now, the representative concepts for a subcritical transmutation reactor are the Energy Amplifier, the OMEGA project, the ATW and the MSBR. The detailed concepts and the specifications are illustrated in Table 1. The design requirements for the subcritical transmutation reactor are the high transmutation rate of long-lived nuclear wastes, safety and economics. And to propose the subcritical transmutation reactor concepts, the coolant, the target material and fuel type are carefully considered. In these aspects, the representative concepts for a subcritical transmutation reactor in Table 1 have been surveyed. The requirements for a target and a coolant are the reliable, low maintenance operation and safe operation to minimize the wastes. The reliable, low maintenance operation and safe operation to minimize the wastes. The reliable coolant must have the low melting point, high heat capacity and excellent physical properties. And the target material must have high neutron yield for a given proton condition and easy heat removal capability. Therefore in respect with the above requirements, Pb-Bi is proposed as the coolant and the target material for the subcritical reactor. Because the neutron yield for a given proton energy increases linearly with mass number up to bismuth but in heavier elements spallation events sharply increase both the neutron and heat outputs, Pb-Bi meets not only such the requirements as the above for the coolant but also those for the coolant and target, the simplification of system can be achieved

  3. Hydrogen co-production from subcritical water-cooled nuclear power plants in Canada

    Energy Technology Data Exchange (ETDEWEB)

    Gnanapragasam, N.; Ryland, D.; Suppiah, S., E-mail: gnanapragasamn@aecl.ca [Atomic Energy of Canada Limited, Chalk River, Ontario (Canada)

    2013-06-15

    Subcritical water-cooled nuclear reactors (Sub-WCR) operate in several countries including Canada providing electricity to the civilian population. The high-temperature-steam-electrolysis process (HTSEP) is a feasible and laboratory-demonstrated large-scale hydrogen-production process. The thermal and electrical integration of the HTSEP with Sub-WCR-based nuclear-power plants (NPPs) is compared for best integration point, HTSEP operating condition and hydrogen production rate based on thermal energy efficiency. Analysis on integrated thermal efficiency suggests that the Sub-WCR NPP is ideal for hydrogen co-production with a combined efficiency of 36%. HTSEP operation analysis suggests that higher product hydrogen pressure reduces hydrogen and integrated efficiencies. The best integration point for the HTSEP with Sub-WCR NPP is upstream of the high-pressure turbine. (author)

  4. Radioresistance increase in polymers at high pressures

    International Nuclear Information System (INIS)

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

    1977-01-01

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

  5. observed by high pressure NMR and NQR

    Indian Academy of Sciences (India)

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

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

    Science.gov (United States)

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

    2010-03-23

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

  7. 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.

  8. 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.

  9. Solubility and degradation of paracetamol in subcritical water

    Directory of Open Access Journals (Sweden)

    Emire Zuhal

    2017-01-01

    Full Text Available In this study, solubility and degradation of paracetamol were examined using subcritical water. Effect of temperature and static time was investigated during solubility process in subcritical water at constant pressure (50 bar. Experimental results show that temperature and static time have crucial effect on the degradation and solubility rates. Maximum mole fraction for solubility of paracetamol was obtained at 403 K as (14.68 ± 0.74×103. Approximation model for solubility of paracetamol was proposed. O2 and H2O2 were used in degradation process of paracetamol. Maximum degradation rate was found as 68.66 ± 1.05 and 100 ± 0.00 % using O2 and H2O2, respectively.

  10. Subcritical to supercritical flow transition in a horizontal stratified flow

    International Nuclear Information System (INIS)

    Asaka, H.; Kukita, Y.

    1995-01-01

    The conditions for a transition from hydraulically subcritical to supercritical flow in the hot legs of a pressurized water reactor (PWR) were studied using data obtained from a two-phase natural circulation experiment conducted at the ROSA-IV Large Scale Test Facility (LSTF). The LSTF is a 1/48 volumetrically-scaled simulator of a Westinghouse-type PWR. The conditions for the transition were compared with the theory of Gardner. While the model explains the trend in the experimental data, the quantitative agreement was not satisfactory. It was found that the conditions for the transition from the subcritical to supercritical flow were predicted well by introducing energy loss term into the theory. (author)

  11. Benchmarking criticality safety calculations with subcritical experiments

    International Nuclear Information System (INIS)

    Mihalczo, J.T.

    1984-06-01

    Calculation of the neutron multiplication factor at delayed criticality may be necessary for benchmarking calculations but it may not be sufficient. The use of subcritical experiments to benchmark criticality safety calculations could result in substantial savings in fuel material costs for experiments. In some cases subcritical configurations could be used to benchmark calculations where sufficient fuel to achieve delayed criticality is not available. By performing a variety of measurements with subcritical configurations, much detailed information can be obtained which can be compared directly with calculations. This paper discusses several measurements that can be performed with subcritical assemblies and presents examples that include comparisons between calculation and experiment where possible. Where not, examples from critical experiments have been used but the measurement methods could also be used for subcritical experiments

  12. 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

  13. 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...

  14. Subcriticality determination in ADS: Valina-Booster experiments

    International Nuclear Information System (INIS)

    Persson, C. M.; Gudowski, W.; Fokau, A.; Bournos, V.; Fokov, Y.; Routkovskaia, C.; Serafimovich, I.; Kiyavitskaya, H.

    2007-01-01

    A major problem in operating a full-scale subcritical accelerator-driven system (ADS) is to ensure sufficient margin to criticality. Therefore, reliable techniques for subcriticality monitoring are required. In order to develop such techniques, a full understanding of existing reactivity determination methods is essential. In this work, reactivity determination methods, such as pulsed neutron source methods and noise methods, are studied experimentally in the subcritical facility YALINA-Booster. YALINA-Booster: The subcritical assembly YALINA-Booster: recently constructed at the Joint Institute for Power and Nuclear Research - Sosny, consists of a subcritical core driven by an external neutron source. The neutron source is a powerful neutron generator consisting of a deuteron accelerator and a target of deuterium or tritium embedded in titanium. Through (d, d) - or (d, t)-reactions neutrons are created with energy around 2.5 MeV and 14.1 MeV respectively. Neutrons are born in the centre of the core and multiply through a lead matrix fuelled with highly enriched uranium (90% and 36%). This zone is referred to as the booster zone and is surrounded by a thermal zone, moderated by polyethylene. In order to reach sufficient high effective multiplication factor, the thermal zone is fuelled by approximately one thousand rods of 10% enriched uranium dioxide in cylindrical geometry. To prevent thermal neutrons from diffusing into the fast booster zone, an interface, consisting of boron carbide and natural uranium rods, is located between the zones. YALINA-Booster has a radial graphite reflector of thickness 24 cm. Experiments: Experiments using the neutron source in pulsed mode will be presented, relying on methods such as the area method and the method of prompt neutron decay rate determination. Moreover, results from noise analysis using for instance the Feynman-α method will be presented

  15. High-purity aluminium creep under high hydrostatic pressure

    International Nuclear Information System (INIS)

    Zajtsev, V.I.; Lyafer, E.I.; Tokij, V.V.

    1977-01-01

    The effect of the hydrostatic pressure on the rate of steady-state creep of high-purity aluminium was investigated. It is shown that the hydrostatic pressure inhibits the creep. The activation volume of the creep is independent of the direction in the range of (4.7-6.2) kg/mm 2 and of the pressure in the range of (1-7.8000) atm. It is concluded that self-diffusion does not control the creep of high-purity aluminium at room temperature in the investigated stress and pressure range

  16. 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

  17. High-Tc superconductors under very high pressure

    International Nuclear Information System (INIS)

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

    1991-01-01

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

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

    Directory of Open Access Journals (Sweden)

    M. Faisal

    2012-05-01

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

  19. 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

  20. 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.

  1. 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.

  2. 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.

  3. 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

  4. Dynamism or Disorder at High Pressures?

    Science.gov (United States)

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

    2002-12-01

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

  5. High pressure photoinduced ring opening of benzene

    International Nuclear Information System (INIS)

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

    2002-01-01

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

  6. 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.

  7. Numerical model for thermoeconomic diagnosis in commercial transcritical/subcritical booster refrigeration systems

    International Nuclear Information System (INIS)

    Ommen, Torben; Elmegaard, Brian

    2012-01-01

    Highlights: ► A transcritical booster refrigeration plant is modelled. ► We examine changes in cost flow at different operation parameters. ► The use of characteristic curves for diagnosis is studied. - Abstract: Transcritical/subcritical booster refrigeration systems are increasingly installed and used in Danish supermarkets. The systems operate in both transcritical and subcritical conditions dependent on the heat rejection performance and the ambient conditions. The plant consists of one refrigerant cycle supplying refrigerant for evaporators in both chilled and frozen display cases. In the paper, thermoeconomic theory is used to establish the cost of cooling at each individual temperature level based on operating costs. With a high amount of operating systems, faulty operation becomes an economic, and environmental, interest. A general solution for evaluation of these systems is considered, with the objective to reduce cost and power consumption of malfunctioning equipment in operation. An analysis of the use of thermoeconomic diagnosis methods is required, as these methods may prove applicable. To accommodate the analysis, a numerical model of a transcritical booster refrigeration plant is considered in this paper. Additionally the characteristic curves method is applied to the high pressure compressor unit of the refrigeration plant. The approach successfully determine whether an anomaly is intrinsic or induced in the component when no uncertainties are introduced in the steady state model.

  8. 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.

  9. Sounding experiments of high pressure gas discharge

    International Nuclear Information System (INIS)

    Biele, Joachim K.

    1998-01-01

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

  10. Measurement of subcriticality by a pulsing α-method

    International Nuclear Information System (INIS)

    Jitarev, V.E.; Kachanov, V.M.; Kuzmin, A.N.

    1999-01-01

    The report presents results of a pulsing α-method [1] for determination of the WWER system subcriticality. The pulsing α-method permits to conduct measurements of system subcriticality in conditions of subcritical state and large neutron background. Therefore this method can be used for the control of a subcriticality of storehouses of a burn up nuclear fuel and stopped reactor. (Authors)

  11. 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...

  12. 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.

  13. 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.

  14. 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)

  15. Analysis of high-pressure safety valves

    NARCIS (Netherlands)

    Beune, A.

    2009-01-01

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

  16. High pressure studies of planetary matter

    International Nuclear Information System (INIS)

    Ross, M.

    1989-06-01

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

  17. 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

  18. High hydrostatic pressure processing of tropical fruits.

    Science.gov (United States)

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

    2010-02-01

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

  19. High pressure neutron powder diffraction at LANSCE

    International Nuclear Information System (INIS)

    Von Dreele, R.B.

    1994-01-01

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

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

    International Nuclear Information System (INIS)

    Matsui, Masanori

    2010-01-01

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

  1. Blue emitting organic semiconductors under high pressure

    DEFF Research Database (Denmark)

    Knaapila, Matti; Guha, Suchismita

    2016-01-01

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

  2. The high-pressure behavior of bloedite

    DEFF Research Database (Denmark)

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

    2014-01-01

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

  3. Optimization of Subcritical Water Extraction of Resveratrol from Grape Seeds by Response Surface Methodology

    Directory of Open Access Journals (Sweden)

    Yajie Tian

    2017-03-01

    Full Text Available The subcritical water extraction (SWE is a high-efficiency and environment-friendly extraction method. The extraction of resveratrol (RES of grape seeds obtained from the wine production process was proposed using subcritical water extraction (SWE. The effects of different extraction process parameters on RES yield were investigated by single factors. Extraction optimization was conducted using response surface methodology (RSM. Extraction temperature was proven to be the most significant factor influencing RES yield. The optimal conditions was as follows: extraction pressure of 1.02 MPa, temperature of 152.32 °C, time of 24.89 min, and a solid/solvent ratio of 1:15 g/mL. Under these optimal conditions, the predicted extraction RES yield was 6.90 μg/g and the recoveries was up to 91.98%. Compared to other previous studies, this method required less pollution and less treatment time to extract RES from grape seeds. From these results, added economic value to this agroindustrial residue is proposed using environmentally friendly extraction techniques.

  4. 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.

  5. High Pressure and Temperature Effects in Polymers

    Science.gov (United States)

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

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

  6. 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...

  7. ENHANCED ELECTROCHEMICAL PROCESSES IN SUBCRITICAL WATER

    Energy Technology Data Exchange (ETDEWEB)

    Steven B. Hawthorne

    2000-07-01

    This project involved designing and performing preliminary electrochemical experiments in subcritical water. An electrochemical cell with substantially better performance characteristics than presently available was designed, built, and tested successfully. The electrochemical conductivity of subcritical water increased substantially with temperature, e.g., conductivities increased by a factor of 120 when the temperature was increased from 25 to 250 C. Cyclic voltammograms obtained with platinum and nickel demonstrated that the voltage required to produce hydrogen and oxygen from water can be dropped by a factor of three in subcritical water compared to the voltages required at ambient temperatures. However, no enhancement in the degradation of 1,2-dichlorobenzene and the polychlorinated biphenyl 3,3',4,4'-tetrachlorobiphenyl was observed with applied potential in subcritical water.

  8. Inspection technology for high pressure pipes

    Energy Technology Data Exchange (ETDEWEB)

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

    2000-02-01

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

  9. High pressure injection injuries: an overview.

    Science.gov (United States)

    Fialkov, J A; Freiberg, A

    1991-01-01

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

  10. Stress concentration effects in high pressure components

    International Nuclear Information System (INIS)

    Aller, J.E.

    1990-01-01

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

  11. High Pressure Multicomponent Adsorption in Porous Media

    DEFF Research Database (Denmark)

    Shapiro, Alexander; Stenby, Erling Halfdan

    1999-01-01

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

  12. 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.

  13. High pressure phase transitions in Europous oxide

    International Nuclear Information System (INIS)

    Kremser, D.T.

    1982-01-01

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

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

    Science.gov (United States)

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

  15. Hydrogen high pressure proportional drift detector

    International Nuclear Information System (INIS)

    Arefiev, A.; Balaev, A.

    1983-01-01

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

  16. 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

  17. 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)

  18. High temperature and pressure electrochemical test station

    DEFF Research Database (Denmark)

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

    2013-01-01

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

  19. SrWO4 at high pressures

    International Nuclear Information System (INIS)

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

    2005-01-01

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

  20. High pressure study of high-temperature superconductors

    Energy Technology Data Exchange (ETDEWEB)

    Souliou, Sofia-Michaela

    2014-09-29

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

  1. High pressure study of high-temperature superconductors

    International Nuclear Information System (INIS)

    Souliou, Sofia-Michaela

    2014-01-01

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

  2. Mechanical weathering and rock erosion by climate-dependent subcritical cracking

    Science.gov (United States)

    Eppes, Martha-Cary; Keanini, Russell

    2017-06-01

    This work constructs a fracture mechanics framework for conceptualizing mechanical rock breakdown and consequent regolith production and erosion on the surface of Earth and other terrestrial bodies. Here our analysis of fracture mechanics literature explicitly establishes for the first time that all mechanical weathering in most rock types likely progresses by climate-dependent subcritical cracking under virtually all Earth surface and near-surface environmental conditions. We substantiate and quantify this finding through development of physically based subcritical cracking and rock erosion models founded in well-vetted fracture mechanics and mechanical weathering, theory, and observation. The models show that subcritical cracking can culminate in significant rock fracture and erosion under commonly experienced environmental stress magnitudes that are significantly lower than rock critical strength. Our calculations also indicate that climate strongly influences subcritical cracking—and thus rock weathering rates—irrespective of the source of the stress (e.g., freezing, thermal cycling, and unloading). The climate dependence of subcritical cracking rates is due to the chemophysical processes acting to break bonds at crack tips experiencing these low stresses. We find that for any stress or combination of stresses lower than a rock's critical strength, linear increases in humidity lead to exponential acceleration of subcritical cracking and associated rock erosion. Our modeling also shows that these rates are sensitive to numerous other environment, rock, and mineral properties that are currently not well characterized. We propose that confining pressure from overlying soil or rock may serve to suppress subcritical cracking in near-surface environments. These results are applicable to all weathering processes.

  3. 30 CFR 57.13021 - High-pressure hose connections.

    Science.gov (United States)

    2010-07-01

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

  4. 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.

  5. Equilibria of ternary system Acetic Acid—Water—CO2 under subcritical conditions

    DEFF Research Database (Denmark)

    JIMENEZ GUTIERREZ, Jose M. (Chema); Mussatto, Solange I.; TSOU, Joana

    Carbon dioxide has been subject of research in the past decades, with special attention targeting different uses of this “greenhouse” gas as raw material, technological fluid, building block or as a carbon supply for fuels, turning it from a pollutant to a green resource. Albeit likely...... it will be returned to the atmosphere (as part of the carbon cycle), CO2 is an inexpensive and clean source with numerous industrial applications in diverse fields: from chemical processes to biotechnological purposes [1]. Many of these studies have been focused on supercritical CO2, due to its broad potential uses...... in a very wide range of applications. However, those conditions, especially the levels of high pressure required at larger scale, involve certain equipment limitations. An alternative to overcome those restrictions is to use subcritical carbon dioxide. In order to understand the different systems...

  6. 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...

  7. 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.

  8. 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

  9. 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

  10. 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.

  11. Calculated characteristics of subcritical assembly with anisotropic transport of neutrons

    International Nuclear Information System (INIS)

    Gorin, N.V.; Lipilina, E.N.; Lyutov, V.D.; Saukov, A.I.

    2003-01-01

    There was considered possibility of creating enough sub-critical system that multiply neutron fluence from a primary source by many orders. For assemblies with high neutron tie between parts, it is impossible. That is why there was developed a construction consisting of many units (cascades) having weak feedback with preceding cascades. The feedback attenuation was obtained placing layers of slow neutron absorber and moderators between the cascades of fission material. Anisotropy of fast neutron transport through the layers was used. The system consisted of many identical cascades aligning one by another. Each cascade consists of layers of moderator, fissile material and absorber of slow neutrons. The calculations were carried out using the code MCNP.4a with nuclear data library ENDF/B5. In this construction neutrons spread predominantly in one direction multiplying in each next fissile layer, and they attenuate considerably in the opposite direction. In a calculated construction, multiplication factor of one cascade is about 1.5 and multiplication factor of whole construction composed of n cascades is 1.5 n . Calculated keff value is 0.9 for one cascade and does not exceed 0.98 for a system containing any number of cascades. Therefore the assembly is always sub-critical and therefore it is safe in respect of criticality. There was considered using such a sub-critical assembly to create a powerful neutron fluence for neutron boron-capturing therapy. The system merits and demerits were discussed. (authors)

  12. 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.

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

    Science.gov (United States)

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

    2015-07-03

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

  14. Large subcriticality measurement by pulsed neutron method

    International Nuclear Information System (INIS)

    Yamane, Y.; Yoshida, A.; Nishina, K.; Kobayashi, K.; Kanda, K.

    1985-01-01

    To establish the method determining large subcriticalities in the field of nuclear criticality safety, the authors performed pulsed neutron experiments using the Kyoto University Critical Assembly (KUCA) at Research Reactor Institute, Kyoto University and the Cockcroft-Walton type accelerator attached to the assembly. The area-ratio method proposed by Sjoestrand was employed to evaluate subcriticalities from neutron decay curves measured. This method has the shortcomings that the neutron component due to a decay of delayed neutrons remarkably decreases as the subcriticality of an objective increases. To overcome the shortcoming, the authors increased the frequency of pulsed neutron generation. The integral-version of the area-ratio method proposed by Kosaly and Fisher was employed in addition in order to remove a contamination of spatial higher modes from the decay curve. The latter becomes significant as subcriticality increases. The largest subcriticality determined in the present experiments was 125.4 dollars, which was equal to 0.5111 in a multiplication factor. The calculational values evaluated by the computer code KENO-IV with 137 energy groups based on the Monte Carlo method agreed well with those experimental values

  15. Food processing by high hydrostatic pressure.

    Science.gov (United States)

    Yamamoto, Kazutaka

    2017-04-01

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

  16. Rheological assessment of nanofluids at high pressure high temperature

    Science.gov (United States)

    Kanjirakat, Anoop; Sadr, Reza

    2013-11-01

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

  17. Ensuring the validity of calculated subcritical limits

    International Nuclear Information System (INIS)

    Clark, H.K.

    1977-01-01

    The care taken at the Savannah River Laboratory and Plant to ensure the validity of calculated subcritical limits is described. Close attention is given to ANSI N16.1-1975, ''Validation of Calculational Methods for Nuclear Criticality Safety.'' The computer codes used for criticality safety computations, which are listed and are briefly described, have been placed in the SRL JOSHUA system to facilitate calculation and to reduce input errors. A driver module, KOKO, simplifies and standardizes input and links the codes together in various ways. For any criticality safety evaluation, correlations of the calculational methods are made with experiment to establish bias. Occasionally subcritical experiments are performed expressly to provide benchmarks. Calculated subcritical limits contain an adequate but not excessive margin to allow for uncertainty in the bias. The final step in any criticality safety evaluation is the writing of a report describing the calculations and justifying the margin

  18. Application of supercritical and subcritical fluids for the extraction of hazardous materials from soil

    Directory of Open Access Journals (Sweden)

    Skorupan Dara

    2002-01-01

    Full Text Available Subcritical and supercritical extractions are novel, non destructive techniques which can be applied for the removal of hazardous compounds from contaminated soil without any changes of the soil composition and structure. The aim of the presented review paper is to give information on up-to day results of this method commonly applied by several institutions worldwide. Interest in the application of SC CO2 has been more expressed in the last two decades, which may be related to its favorable characteristics (non-toxic, non-flammable, increase diffusion into small pores, low viscosity under SC conditions, low price and others. However, interest in wet oxidation (WO and especially in SCWO (the application of water under supercritical conditions with air has also increased in the last few years. Interest in H2O as a SC fluid, as well as in extraction with water under subcritical conditions may also be related to specific characteristics and the enhanced rate of extraction. Moreover, the solubility of some specific compounds present in soil can be easily changed by adjusting the pressure and temperature of extraction. The high price of the units designed to operate safely at a pressure and temperature much higher than the a critical one of the applied fluids is the main reason why, at present, there is no more broader application of such techniques for the removal hazardous materials from contaminated soil. In the present paper, among many literature citations and their overall review, some specific details related to the development of specific analytical methods under SC conditions are also considered.

  19. Engineering Model of High Pressure Moist Air

    Directory of Open Access Journals (Sweden)

    Hyhlík Tomáš

    2017-01-01

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

  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. 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.

  2. Experimental subcritical facility driven by D-D/D-T neutron generator at BARC, India

    Energy Technology Data Exchange (ETDEWEB)

    Sinha, Amar, E-mail: image@barc.gov.in; Roy, Tushar; Kashyap, Yogesh; Ray, Nirmal; Shukla, Mayank; Patel, Tarun; Bajpai, Shefali; Sarkar, P.S.; Bishnoi, Saroj

    2015-05-01

    Highlights: •Experimental subcritical facility BRAHMMA coupled to D-D/D-T neutron generator. •Preliminary results of PNS experiments reported. •Feynman-alpha noise measurements explored with continuous source. -- Abstract: The paper presents design of an experimental subcritical assembly driven by D-D/D-T neutron and preliminary experimental measurements. The system has been developed for investigating the static and dynamic neutronic properties of accelerator driven sub-critical systems. This system is modular in design and it is first in the series of subcritical assemblies being designed. The subcritical core consists of natural uranium fuel with high density polyethylene as moderator and beryllium oxide as reflector. The fuel is embedded in high density polyethylene moderator matrix. Estimated k{sub eff} of the system is ∼0.89. One of the unique features of subcritical core is the use of Beryllium oxide (BeO) as reflector and HDPE as moderator making the assembly a compact modular system. The subcritical core is coupled to Purnima Neutron Generator which works in D-D and D-T mode with both DC and pulsed operation. It has facility for online source strength monitoring using neutron tagging and programmable source modulation. Preliminary experiments have been carried out for spatial flux measurement and reactivity estimation using pulsed neutron source (PNS) techniques with D-D neutrons. Further experiments are being planned to measure the reactivity and other kinetic parameters using noise methods. This facility would also be used for carrying out studies on effect of source importance and measurement of source multiplication factor k{sub s} and external neutron source efficiency φ{sup ∗} in great details. Experiments with D-T neutrons are also underway.

  3. Modeling of Parameters of Subcritical Assembly SAD

    CERN Document Server

    Petrochenkov, S; Puzynin, I

    2005-01-01

    The accepted conceptual design of the experimental Subcritical Assembly in Dubna (SAD) is based on the MOX core with a nominal unit capacity of 25 kW (thermal). This corresponds to the multiplication coefficient $k_{\\rm eff} =0.95$ and accelerator beam power 1 kW. A subcritical assembly driven with the existing 660 MeV proton accelerator at the Joint Institute for Nuclear Research has been modelled in order to make choice of the optimal parameters for the future experiments. The Monte Carlo method was used to simulate neutron spectra, energy deposition and doses calculations. Some of the calculation results are presented in the paper.

  4. Continuous reactivity calculation for subcritical system

    International Nuclear Information System (INIS)

    Silva, Cristiano; Goncalves, Alessandro C.; Martinez, Aquilino S.; Silva, Fernando C. da

    2011-01-01

    With the rise of a new generation of nuclear reactors as for existence the ADS (Accelerator-Driven System), it is important to have a fast and accurate prediction of the variation in reactivity during a possible variation in the intensity of external sources. This paper presents a formulation for the calculation of reactivity in subcritical systems using the inverse method related only to nuclear power derivatives. One of the applications of the proposed method is the possibility of developing reactimeters that allow the continuous monitoring of subcritical systems. (author)

  5. Continuous reactivity calculation for subcritical system

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Cristiano; Goncalves, Alessandro C.; Martinez, Aquilino S.; Silva, Fernando C. da, E-mail: cristiano@herzeleid.net, E-mail: aquilino@lmp.ufrj.br, E-mail: fernando@con.ufrj.br [Coordenacao dos Programas de Pos-Graduacao em Engenharia (PEN/COPPE/UFRJ), Rio de Janeiro, RJ (Brazil). Programa de Engenharia Nuclear; Palma, Daniel A.P., E-mail: dapalma@cnen.gov.br [Comissao Nacional de Energia Nuclear (CNEN), Rio de Janeiro, RJ (Brazil)

    2011-07-01

    With the rise of a new generation of nuclear reactors as for existence the ADS (Accelerator-Driven System), it is important to have a fast and accurate prediction of the variation in reactivity during a possible variation in the intensity of external sources. This paper presents a formulation for the calculation of reactivity in subcritical systems using the inverse method related only to nuclear power derivatives. One of the applications of the proposed method is the possibility of developing reactimeters that allow the continuous monitoring of subcritical systems. (author)

  6. Subcritical calculation of the nuclear material warehouse

    International Nuclear Information System (INIS)

    Garcia M, T.; Mazon R, R.

    2009-01-01

    In this work the subcritical calculation of the nuclear material warehouse of the Reactor TRIGA Mark III labyrinth in the Mexico Nuclear Center is presented. During the adaptation of the nuclear warehouse (vault I), the fuel was temporarily changed to the warehouse (vault II) and it was also carried out the subcritical calculation for this temporary arrangement. The code used for the calculation of the effective multiplication factor, it was the Monte Carlo N-Particle Extended code known as MCNPX, developed by the National Laboratory of Los Alamos, for the particles transport. (Author)

  7. Computer simulations of high pressure systems

    International Nuclear Information System (INIS)

    Wilkins, M.L.

    1977-01-01

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

  8. 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.

  9. Recent developments in high pressure water technology

    International Nuclear Information System (INIS)

    Johnson, N.A.; Johnson, T.

    1992-01-01

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

  10. 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.

  11. High-pressure structures of methane hydrate

    International Nuclear Information System (INIS)

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

    2002-01-01

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

  12. 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

  13. 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)

  14. 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 ...

  15. 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 ...

  16. 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 ...

  17. Subcritical-Water Extraction of Organics from Solid Matrices

    Science.gov (United States)

    Amashukeli, Xenia; Grunthaner, Frank; Patrick, Steven; Kirby, James; Bickler, Donald; Willis, Peter; Pelletier, Christine; Bryson, Charles

    2009-01-01

    An apparatus for extracting organic compounds from soils, sands, and other solid matrix materials utilizes water at subcritical temperature and pressure as a solvent. The apparatus, called subcritical water extractor (SCWE), is a prototype of subsystems of future instrumentation systems to be used in searching for organic compounds as signs of past or present life on Mars. An aqueous solution generated by an apparatus like this one can be analyzed by any of a variety of established chromatographic or spectroscopic means to detect the dissolved organic compound( s). The apparatus can be used on Earth: indeed, in proof-of-concept experiments, SCWE was used to extract amino acids from soils of the Atacama Desert (Chile), which was chosen because the dryness and other relevant soil conditions there approximate those on Mars. The design of the apparatus is based partly on the fact that the relative permittivity (also known as the dielectric constant) of liquid water varies with temperature and pressure. At a temperature of 30 C and a pressure of 0.1 MPa, the relative permittivity of water is 79.6, due to the strong dipole-dipole electrostatic interactions between individual molecular dipoles. As the temperature increases, increasing thermal energy causes increasing disorientation of molecular dipoles, with a consequent decrease in relative permittivity. For example, water at a temperature of 325 C and pressure of 20 MPa has a relative permittivity of 17.5, which is similar to the relative permittivities of such nonpolar organic solvents as 1-butanol (17.8). In the operation of this apparatus, the temperature and pressure of water are adjusted so that the water can be used in place of commonly used organic solvents to extract compounds that have dissimilar physical and chemical properties.

  18. Effect of high pressure on mesophilic lactic fermentation streptococci

    Energy Technology Data Exchange (ETDEWEB)

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

    2008-07-15

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

  19. 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.

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

    Czech Academy of Sciences Publication Activity Database

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

    2002-01-01

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

  1. Burning of spent fuel of an accelerator-driven modular HTGR in sub-critical condition

    International Nuclear Information System (INIS)

    Jing Xingqing; Yang Yongwei; Chang Hong; Wu Zongxin; Gu Yuxiang

    2002-01-01

    The modular high temperature gas cooled reactor (MHTGR) has good safety characteristics because of the use of coated particles in the fuel element. After the particles cool outside of the reactor for some time, the spent fuel can be re-utilized. The author describes a physics feasibility study for the burning of spent fuel from a 350 MW ring-shaped modular high temperature gas cooled reactor in an accelerator-driven sub-critical reactor. A conceptual design is given for the 30 MW accelerator-driven sub-critical reactor. The neutron transport in the sub-critical reactor was simulated using the MCNP code, and the burnup was calculated using the ORIGEN2 code. The results show that the accelerator-driven sub-critical gas-cooled reactor has reliable sub-criticality and low power density and that the spent fuel from a 350 MW ring-shaped modular high temperature gas cooled reactor can be burned to provide 20% more energy

  2. Physics analyses of an accelerator-driven sub-critical assembly

    Science.gov (United States)

    Naberezhnev, Dmitry G.; Gohar, Yousry; Bailey, James; Belch, Henry

    2006-06-01

    Physics analyses have been performed for an accelerator-driven sub-critical assembly as a part of the Argonne National Laboratory activity in preparation for a joint conceptual design with the Kharkov Institute of Physics and Technology (KIPT) of Ukraine. KIPT has a plan to construct an accelerator-driven sub-critical assembly targeted towards the medical isotope production and the support of the Ukraine nuclear industry. The external neutron source is produced either through photonuclear reactions in tungsten or uranium targets, or deuteron reactions in a beryllium target. KIPT intends using the high-enriched uranium (HEU) for the fuel of the sub-critical assembly. The main objective of this paper is to study the possibility of utilizing low-enriched uranium (LEU) fuel instead of HEU fuel without penalizing the sub-critical assembly performance, in particular the neutron flux level. In the course of this activity, several studies have been carried out to investigate the main choices for the system's parameters. The external neutron source has been characterized and a pre-conceptual target design has been developed. Several sub-critical configurations with different fuel enrichments and densities have been considered. Based on our analysis, it was shown that the performance of the LEU fuel is comparable with that of the HEU fuel. The LEU fuel sub-critical assembly with 200-MeV electron energy and 100-kW electron beam power has an average total flux of ˜2.50×10 13 n/s cm 2 in the irradiation channels. The corresponding total facility power is ˜204 kW divided into 91 and 113 kW deposited in the target and sub-critical assemblies, respectively.

  3. 30 CFR 56.13021 - High-pressure hose connections.

    Science.gov (United States)

    2010-07-01

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

  4. 76 FR 38697 - High Pressure Steel Cylinders From China

    Science.gov (United States)

    2011-07-01

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

  5. 77 FR 37712 - High Pressure Steel Cylinders From China

    Science.gov (United States)

    2012-06-22

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

  6. Single stage high pressure centrifugal slurry pump

    Science.gov (United States)

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

    1984-03-27

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

  7. 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.)

  8. High Pressure Laminates with Antimicrobial Properties

    Directory of Open Access Journals (Sweden)

    Sandra Magina

    2016-02-01

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

  9. Large eddy simulation of the subcritical flow over a V grooved circular cylinder

    International Nuclear Information System (INIS)

    Alonzo-García, A.; Gutiérrez-Torres, C. del C.; Jiménez-Bernal, J.A.

    2015-01-01

    Highlights: • We compared numerically the turbulent flow over a smooth circular cylinder and a V grooved cylinder in the subcritical regime. • Turbulence intensities in both streamwise and normal direction suffered attenuations. • The swirls structures on grooves peaks seemed to have a cyclic behavior. • The evolution of the flow inside grooves showed that swirls structures located in peaks suffered elongations in the normal direction. • The secondary vortex structures formed in the grooved cylinder near wake were smaller in comparison of the smooth cylinder flow. - Abstract: In this paper, a comparative numerical study of the subcritical flow over a smooth cylinder and a cylinder with V grooves (Re = 140,000) is presented. The implemented technique was the Large Eddy Simulation (LES), which according to Kolmogorov's theory, resolves directly the most energetic largest eddies and models the smallest and considered universal high frequency ones. The Navier-Stokes (N-S) equations were solved using the commercial software ANSYS FLUENT V.12.1, which applied the finite volume method (FVM) to discretize these equations in their unsteady and incompressible forms. The grid densities were 2.6 million cells and 13.5 million cells for the smooth and V grooved cylinder, respectively. Both meshes were composed of structured hexahedral cells and close to the wall of the cylinders, additional refinements were employed in order to obtain y +<5 values. All cases were simulated during at least 15 vortex shedding cycles with the aim of obtaining significant statistical data. Results: showed that for both cases (smooth and V grooved cylinder flow), the numerical code was capable of reproducing the most important physical quantities of the subcritical regime. Velocity distribution and turbulence intensity in the flow direction suffered a slight attenuation along the wake, as a consequence of grooves perturbation, which also caused an increase in the pressure coefficient

  10. 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.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2010-06-15

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

  12. 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.

  13. Physics study of D-D/D-T neutron driven experimental subcritical assembly

    International Nuclear Information System (INIS)

    Sinha, Amar

    2015-01-01

    An experimental program to design and study external source driven subcritical assembly has been initiated at BARC. This program is aimed at understanding neutronic characteristics of accelerator driven system at low power level. In this series, a zero-power, sub-critical assembly driven by a D-D/D-T neutron generator has been developed. This system is modular in design and it is first in the series of subcritical assemblies being designed. The subcritical core consists of natural uranium fuel with high density polyethylene as moderator and beryllium oxide as reflector. The subcritical core is coupled to Purnima Neutron Generator. Preliminary experiments have been carried out for spatial flux measurement and reactivity estimation using pulsed neutron source (PNS) techniques. Further experiments are being planned to measure the reactivity and other kinetic parameters using noise methods. This facility would also be used for carrying out studies on effect of source importance and measurement of source multiplication factor k s and external neutron source efficiency φ* in great details. Some experiments with D-D and D-T neutrons have been presented. (author)

  14. High cost of stage IV pressure ulcers.

    Science.gov (United States)

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

    2010-10-01

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

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

    Science.gov (United States)

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

  16. 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...

  17. Preliminary analysis of advanced equilibrium configuration for the fusion-driven subcritical system

    International Nuclear Information System (INIS)

    Chu Delin; Wu Bin; Wu Yican

    2003-01-01

    The Fusion-Driven Subcritical System (FDS) is a subcritical nuclear energy system driven by fusion neutron source. In this paper, an advanced plasma configuration for FDS system has been proposed, which aims at high beta, high bootstrap current and good confinement. A fixed-boundary equilibrium code has been used to obtain ideal equilibrium configuration. In order to determine the feasibility of FDS operation, a two-dimensional time-dependent free boundary simulation code has been adopted to simulate time-scale evolution of plasma current profile and boundary position. By analyses, the Reversed Shear mode as the most attractive one has been recommended for the FDS equilibrium configuration design

  18. High-temperature fiber optic pressure sensor

    Science.gov (United States)

    Berthold, J. W.

    1984-01-01

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

  19. GENERATION OF HIGH SHOCK PRESSURES BY LASER PULSES

    OpenAIRE

    Romain , J.

    1984-01-01

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

  20. Theoretical Analysis for Heat Transfer Optimization in Subcritical Electrothermal Energy Storage Systems

    Directory of Open Access Journals (Sweden)

    Peng Hu

    2017-02-01

    Full Text Available Electrothermal energy storage (ETES provides bulk electricity storage based on heat pump and heat engine technologies. A subcritical ETES is described in this paper. Based on the extremum principle of entransy dissipation, a geometry model is developed for heat transfer optimization for subcritical ETES. The exergy during the heat transfer process is deduced in terms of entropy production. The geometry model is validated by the extremum principle of entropy production. The theoretical analysis results show that the extremum principle of entransy dissipation is an effective criterion for the optimization, and the optimum heat transfer for different cases with the same mass flux or pressure has been discussed. The optimum heat transfer can be achieved by adjusting the mass flux and pressure of the working fluid. It also reveals that with the increase of mass flux, there is a minimum exergy in the range under consideration, and the exergy decreases with the increase of the pressure.

  1. High Temperature Characterization of Ceramic Pressure Sensors

    National Research Council Canada - National Science Library

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

    2001-01-01

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

  2. 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.

  3. Non-Catalytic and MgSO4 - Catalyst based Degradation of Glycerol in Subcritical and Supercritical Water Media

    Directory of Open Access Journals (Sweden)

    Mahfud Mahfud

    2011-02-01

    Full Text Available This research aims to study the glycerol degradation reaction in subcritical and supercritical water media. The degradation of glycerol into other products was performed both with sulphate salt catalysts and without catalyst. The reactant was made from glycerol and water with the mass ratio of 1:10. The experiments were carried out using a batch reactor at a constant pressure of 250 kgf/cm2, with the temperature range of 200-400oC, reaction time of 30 minutes, and catalyst mol ratio in glycerol of 1:10 and 1:8. The products of the non-catalytic glycerol degradation were acetaldehyde, methanol, and ethanol. The use of sulphate salt as catalyst has high selectivity to acetaldehyde and still allows the formation alcohol product in small quantities. The mechanism of ionic reaction and free radical reaction can occur at lower temperature in hydrothermal area or subcritical water. Conversion of glycerol on catalytic reaction showed a higher yield when compared with the reaction performed without catalyst

  4. Elasticity of stishovite at high pressure

    Science.gov (United States)

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

    1996-08-01

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

  5. High-pressure system for Compton scattering experiments

    International Nuclear Information System (INIS)

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

    1998-01-01

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

  6. 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

  7. 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.

  8. Production of rare sugars from common sugars in subcritical aqueous ethanol.

    Science.gov (United States)

    Gao, Da-Ming; Kobayashi, Takashi; Adachi, Shuji

    2015-05-15

    A new isomerization reaction was developed to synthesize rare ketoses. D-tagatose, D-xylulose, and D-ribulose were obtained in the maximum yields of 24%, 38%, and 40%, respectively, from the corresponding aldoses, D-galactose, D-xylose, and D-ribose, by treating the aldoses with 80% (v/v) subcritical aqueous ethanol at 180°C. The maximum productivity of D-tagatose was ca. 80 g/(Lh). Increasing the concentration of ethanol significantly increased the isomerization of D-galactose. Variation in the reaction temperature did not significantly affect the production of D-tagatose from D-galactose. Subcritical aqueous ethanol converted both 2,3-threo and 2,3-erythro aldoses to the corresponding C-2 ketoses in high yields. Thus, the treatment of common aldoses in subcritical aqueous ethanol can be regarded as a new method to synthesize the corresponding rare sugars. Copyright © 2014 Elsevier Ltd. All rights reserved.

  9. Validation of neutronic methods applied to the analysis of fast subcritical systems. The MUSE-2 experiments

    International Nuclear Information System (INIS)

    Soule, R.; Salvatores, M.; Jacqmin, R.; Martini, M.; Lebrat, J.F.; Bertrand, P.; Broccoli, U.; Peluso, V.

    1997-01-01

    In the framework of the French SPIN program devoted to the separation and the transmutation of radioactive wastes, the CEA has launched the ISAAC program to investigate the potential of accelerator-driven systems and to provide an experimental validation of the physics characteristics of these systems. The neutronics of the subcritical core needs experimental validation. This can be done by decoupling the problem of the neutron source from the problem of the subcritical medium. Experiments with a well known external source placed in a subcritical medium have been performed in the MASURCA facility. The results confirm the high accuracy achievable with such experiments and the good quality of the ERANOS code system predictions. (author)

  10. Validation of neutronic methods applied to the analysis of fast subcritical systems. The MUSE-2 experiments

    Energy Technology Data Exchange (ETDEWEB)

    Soule, R; Salvatores, M; Jacqmin, R; Martini, M; Lebrat, J F; Bertrand, P [CEA Centre d` Etudes de Cadarache, Service de Physique des Reacteurs et du Cycle, 13 - Saint-Paul-lez-Durance (France); Broccoli, U; Peluso, V

    1998-12-31

    In the framework of the French SPIN program devoted to the separation and the transmutation of radioactive wastes, the CEA has launched the ISAAC program to investigate the potential of accelerator-driven systems and to provide an experimental validation of the physics characteristics of these systems. The neutronics of the subcritical core needs experimental validation. This can be done by decoupling the problem of the neutron source from the problem of the subcritical medium. Experiments with a well known external source placed in a subcritical medium have been performed in the MASURCA facility. The results confirm the high accuracy achievable with such experiments and the good quality of the ERANOS code system predictions. (author)

  11. 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.

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

    CERN Document Server

    Johnson, R P

    2004-01-01

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

  13. Subcritical tests - nuclear weapon testing under the Comprehensive Test Ban Treaty; Subkritiske tester - kjernevaapentesting under avtalen om fullstendig proevestans

    Energy Technology Data Exchange (ETDEWEB)

    Hoeibraaten, S

    1998-10-01

    The report discusses possible nuclear weapons related experiments and whether these are permitted under the 1996 Comprehensive Test Ban Treaty (CTBT). The term ''subcritical experiments'' as used in the United States includes experiments in which one studies fissile materials (so far only plutonium) under extreme conditions generated by conventional high explosives, and in which a self-sustained chain reaction never develops in the fissile material. The known facts about the American subcritical experiments are presented. There is very little reason to doubt that these experiments were indeed subcritical and therefore permitted under the CTBT. Little is known about the Russian efforts that are being made on subcritical experiments.

  14. Formation of InAs/GaAs quantum dots from a subcritical InAs wetting layer: A reflection high-energy electron diffraction and theoretical study

    International Nuclear Information System (INIS)

    Song, H. Z.; Usuki, T.; Nakata, Y.; Yokoyama, N.; Sasakura, H.; Muto, S.

    2006-01-01

    InAs/GaAs quantum dots (QD's) are formed by postgrowth annealing of an InAs wetting layer thinner than the critical thickness for the transition from two- (2D) to three-dimensional (3D) growth mode. Reflection high energy electron diffraction is used to monitor the QD formation. Based on a mean-field theory [Phys. Rev. Lett. 79, 897 (1997)], the time evolution of total QD's volume, first increasing and finally saturating, is well explained by precursors forming during wetting layer growth and converting into nucleated QD's after growth stop. Both the saturation QD's volume and the QD nucleation rate depend exponentially on the InAs coverage. These behaviors and their temperature and InAs growth rate dependences are essentially understandable in the frame of the mean-field theory. Similar analysis to conventional QD growth suggests that the often observed significant mass transport from wetting layer to QD's can be ascribed to the precursors existing before 2D-3D growth mode transition

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

    International Nuclear Information System (INIS)

    Park, Kwangheon; Kim, Kwangpyo; Ryu, Taegeun

    2000-01-01

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

  16. 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)

  17. Subcritical Measurements Research Program for Fresh and Spent Materials Test Reactor Fuels

    International Nuclear Information System (INIS)

    Blanchard, A.

    1999-01-01

    'A series of subcritical noise measurements were performed on fresh and spent University of Missouri Research Reactor fuel assemblies. These experimental measurements were performed for the purposes of providing benchmark quality data for validating transport theory computer codes and nuclear cross-section data used to perform criticality safety analyses for highly enriched, uranium-aluminum Material Test Reactor fuel assemblies. A mechanical test rig was designed and built to hold up to four fuel assemblies and neutron detectors in a subcritical array. The rig provided researchers with the ability to evaluate the reactivity effects of variable fuel/detector spacing, fuel rotation, and insertion of metal reflector plates into the lattice.'

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

    NARCIS (Netherlands)

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

    2002-01-01

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

  19. Viscosity of liquid sulfur under high pressure

    International Nuclear Information System (INIS)

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

    2004-01-01

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

  20. 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).

  1. 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.

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

    Centers for Disease Control (CDC) Podcasts

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

  3. 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.

  4. 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...

  5. Generation of high shock pressures by laser pulses

    Energy Technology Data Exchange (ETDEWEB)

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

    1984-11-01

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

  6. Generation of high shock pressures by laser pulses

    International Nuclear Information System (INIS)

    Romain, J.P.

    1984-01-01

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

  7. 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

  8. Magnetization at high pressure in CeP

    Science.gov (United States)

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

    1995-02-01

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

  9. High pressure studies of fluorenone emission in plastic media

    International Nuclear Information System (INIS)

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

    1977-01-01

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

  10. Subcritical limits for special fissile actinides

    International Nuclear Information System (INIS)

    Clark, H.K.

    1980-01-01

    Critical masses and subcritical mass limits in oxide-water mixtures were calculated for actinide nuclides other than /sup 233/U, /sup 235/U, and /sup 239/Pu that have an odd number of neutrons in the nucleus; S/sub n/ transport theory was used together with cross sections, drawn from the GLASS multigroup library, developed to provide accurate forecasts of actinide production at Savannah River

  11. Proposed dedicated high pressure beam lines at CHESS

    International Nuclear Information System (INIS)

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

    1988-01-01

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

  12. 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 ...

  13. High pressure argon detector of high energy neutrinos

    International Nuclear Information System (INIS)

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

    1979-01-01

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

  14. 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

  15. 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)

  16. High pressure multiple shock response of aluminum

    International Nuclear Information System (INIS)

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

    1977-01-01

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

  17. Deep subcritical levels measurements dependents upon kinetic distortion factors

    International Nuclear Information System (INIS)

    Pan Shibiao; Li Xiang; Fu Guo'en; Huang Liyuan; Mu Keliang

    2013-01-01

    The measurement of deep subcritical levels, with the increase of subcriticality, showed that the results impact on the kinetic distortion effect, along with neutron flux strongly deteriorated. Using the diffusion theory, calculations have been carried out to quantify the kinetic distortion correction factors in subcritical systems, and these indicate that epithermal neutron distributions are strongly affected by kinetic distortion. Subcriticality measurements in four different rod-state combination at the zero power device was carried out. The test data analysis shows that, with increasing subcriticality, kinetic distortion effect correction factor gradually increases from 1.052 to 1.065, corresponding reactive correction amount of 0.78β eff ∼ 3.01β eff . Thus, it is necessary to consider the kinetic distortion effect in the deep subcritical reactivity measurements. (authors)

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

    International Nuclear Information System (INIS)

    Anandkumar, V.

    1997-01-01

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

  19. Solid gas reaction phase diagram under high gas pressure

    International Nuclear Information System (INIS)

    Ishizaki, K.

    1992-01-01

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

  20. 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)

  1. Pressurizer pump reliability analysis high flux isotope reactor

    International Nuclear Information System (INIS)

    Merryman, L.; Christie, B.

    1993-01-01

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

  2. Design project of fast subcritical system 'Mala Lasta'

    International Nuclear Information System (INIS)

    Milosevic, M.; Stefanovic, D.; Popovic, D.; Pesic, M.; Zavaljevski, N.; Nikolic, D.; Arsenovic, M.

    1988-10-01

    This report contains two parts. Part one covers the objective and fundamental elements for the choice of fast subcritical system 'Mala Lasta', review of the existing fast subcritical assemblies, and a description of the available domestic computer codes applied for calculating neutron reactor parameters. Comparison of results obtained by these codes for a number of existing subcritical assemblies was used for the choice of the design project described in part two of this report. It contains detailed description of the operating parameters of the chosen subcritical system based on the obtained calculated parameters

  3. High Temperature and Pressure Alkaline Electrolysis

    DEFF Research Database (Denmark)

    Allebrod, Frank

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

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

    Directory of Open Access Journals (Sweden)

    Yancheng Meng

    2018-05-01

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

  5. 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 ...

  6. How Potassium Can Help Control High Blood Pressure

    Science.gov (United States)

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

  7. How High Blood Pressure Can Lead to Stroke

    Science.gov (United States)

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

  8. 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 ...

  9. 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

  10. Impurity trapped excitons under high hydrostatic pressure

    Science.gov (United States)

    Grinberg, Marek

    2013-09-01

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

  11. Microstructures define melting of molybdenum at high pressures

    Science.gov (United States)

    Hrubiak, Rostislav; Meng, Yue; Shen, Guoyin

    2017-03-01

    High-pressure melting anchors the phase diagram of a material, revealing the effect of pressure on the breakdown of the ordering of atoms in the solid. An important case is molybdenum, which has long been speculated to undergo an exceptionally steep increase in melting temperature when compressed. On the other hand, previous experiments showed nearly constant melting temperature as a function of pressure, in large discrepancy with theoretical expectations. Here we report a high-slope melting curve in molybdenum by synchrotron X-ray diffraction analysis of crystalline microstructures, generated by heating and subsequently rapidly quenching samples in a laser-heated diamond anvil cell. Distinct microstructural changes, observed at pressures up to 130 gigapascals, appear exclusively after melting, thus offering a reliable melting criterion. In addition, our study reveals a previously unsuspected transition in molybdenum at high pressure and high temperature, which yields highly textured body-centred cubic nanograins above a transition temperature.

  12. High-Pressure Oxygen Generation for Outpost EVA Study

    Science.gov (United States)

    Jeng, Frank F.; Conger, Bruce; Ewert, Michael K.; Anderson, Molly S.

    2009-01-01

    The amount of oxygen consumption for crew extravehicular activity (EVA) in future lunar exploration missions will be significant. Eight technologies to provide high pressure EVA O2 were investigated. They are: high pressure O2 storage, liquid oxygen (LOX) storage followed by vaporization, scavenging LOX from Lander followed by vaporization, LOX delivery followed by sorption compression, water electrolysis followed by compression, stand-alone high pressure water electrolyzer, Environmental Control and Life Support System (ECLSS) and Power Elements sharing a high pressure water electrolyzer, and ECLSS and In-Situ Resource Utilization (ISRU) Elements sharing a high pressure electrolyzer. A trade analysis was conducted comparing launch mass and equivalent system mass (ESM) of the eight technologies in open and closed ECLSS architectures. Technologies considered appropriate for the two architectures were selected and suggested for development.

  13. 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.

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

    Energy Technology Data Exchange (ETDEWEB)

    Milinchuk, V; KIRJUKHIN, V; KLINSHPONT, E

    1977-06-01

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

  15. Protection against high intravascular pressure in giraffe legs

    DEFF Research Database (Denmark)

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

    2013-01-01

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

  16. 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

  17. Development of high pressure pipe scanners

    International Nuclear Information System (INIS)

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

    1998-12-01

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

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

    International Nuclear Information System (INIS)

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

    1987-01-01

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

  19. High-pressure applications in medicine and pharmacology

    Energy Technology Data Exchange (ETDEWEB)

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

    2004-04-14

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

  20. High-pressure applications in medicine and pharmacology

    International Nuclear Information System (INIS)

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

    2004-01-01

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

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

    International Nuclear Information System (INIS)

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

    2008-01-01

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

  2. A novel SOI pressure sensor for high temperature application

    International Nuclear Information System (INIS)

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

    2015-01-01

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

  3. Subcritical Water Extraction of Amino Acids from Atacama Desert Soils

    Science.gov (United States)

    Amashukeli, Xenia; Pelletier, Christine C.; Kirby, James P.; Grunthaner, Frank J.

    2007-01-01

    Amino acids are considered organic molecular indicators in the search for extant and extinct life in the Solar System. Extraction of these molecules from a particulate solid matrix, such as Martian regolith, will be critical to their in situ detection and analysis. The goals of this study were to optimize a laboratory amino acid extraction protocol by quantitatively measuring the yields of extracted amino acids as a function of liquid water temperature and sample extraction time and to compare the results to the standard HCl vapor- phase hydrolysis yields for the same soil samples. Soil samples from the Yungay region of the Atacama Desert ( Martian regolith analog) were collected during a field study in the summer of 2005. The amino acids ( alanine, aspartic acid, glutamic acid, glycine, serine, and valine) chosen for analysis were present in the samples at concentrations of 1 - 70 parts- per- billion. Subcritical water extraction efficiency was examined over the temperature range of 30 - 325 degrees C, at pressures of 17.2 or 20.0 MPa, and for water- sample contact equilibration times of 0 - 30 min. None of the amino acids were extracted in detectable amounts at 30 degrees C ( at 17.2 MPa), suggesting that amino acids are too strongly bound by the soil matrix to be extracted at such a low temperature. Between 150 degrees C and 250 degrees C ( at 17.2 MPa), the extraction efficiencies of glycine, alanine, and valine were observed to increase with increasing water temperature, consistent with higher solubility at higher temperatures, perhaps due to the decreasing dielectric constant of water. Amino acids were not detected in extracts collected at 325 degrees C ( at 20.0 MPa), probably due to amino acid decomposition at this temperature. The optimal subcritical water extraction conditions for these amino acids from Atacama Desert soils were achieved at 200 degrees C, 17.2 MPa, and a water- sample contact equilibration time of 10 min.

  4. 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.)

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

    International Nuclear Information System (INIS)

    Mermelstein, N.H.

    1997-01-01

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

  6. High pressure orthorhombic structure of CuInSe2

    International Nuclear Information System (INIS)

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

    2010-01-01

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

  7. 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.)

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

    International Nuclear Information System (INIS)

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

    2003-01-01

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

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

    International Nuclear Information System (INIS)

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

    1979-01-01

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

  10. 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

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

    International Nuclear Information System (INIS)

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

    2012-01-01

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

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

    International Nuclear Information System (INIS)

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

    1994-01-01

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

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

    Science.gov (United States)

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

    2016-04-14

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

  14. 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.

  15. Hydrolysis of corn oil using subcritical water

    Directory of Open Access Journals (Sweden)

    Pinto Jair Sebastião S.

    2006-01-01

    Full Text Available This work presents the results of a study on the use of subcritical water as both solvent and reactant for the hydrolysis of corn oil without the use of acids or alkalis at temperatures of 150-280 degreesC. Corn oil hydrolysis leads to the formation of its respective fatty acids with the same efficiency of conventional methods. Fatty acids form an important group of products, which are used in a range of applications. The confirmation and identification of the hydrolysis products was done by HT-HRGC-FID and HRGC/MS.

  16. High-pressure phase transition in Ho2O3

    International Nuclear Information System (INIS)

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

    2010-01-01

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

  17. Mechanically recovered poultry meat sausages manufactured with high hydrostatic pressure.

    Science.gov (United States)

    Yuste, J; Mor-Mur, M; Capellas, M; Guamis, B; Pla, R

    1999-06-01

    The effect of high pressure processing at high temperature on texture and color of frankfurter-type sausages made with different contents of mechanically recovered poultry meat (MRPM) was evaluated and compared with that of a standard cooking process. Five types of sausages containing 100, 75, 50, 25, and 0% MRPM and 0, 25, 50, 75, and 100% of minced pork meat (MPM), respectively, were manufactured. They were pressurized at 500 MPa for 30 min at 50, 60, 70, and 75 C or cooked at 75 C for 30 min. Pressure-treated sausages were less springy and firm, but more cohesive. Moreover, color of pressurized sausages was lighter and more yellow than that of conventionally cooked sausages. Addition of MPM increased cohesiveness, hardness, and force at 80% compression. Minced pork meat also caused the appearance of sausages to be lighter, less red, and less yellow. Cooked sausages made with MRPM can have an attractive appearance and texture via high pressure processing.

  18. 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.

  19. 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.

  20. HIGH HYDROSTATIC PRESSURE SYSTEMS USE IN FOOD INDUSTRY

    OpenAIRE

    Yahya TÜLEK; Gökçe FİLİZAY

    2006-01-01

    Food preservation is a continuous fight against microorganisms spoiling the food or making it unsafe. The last decade, non-thermal inactivation techniques have been a major research issue, driven by an increased consumer demand for nutritious, fresh like food products with a high organoleptical quality and an acceptable shelf life. Investigated inactivation technologies are ionisation radiation, high hydrostatic pressure (HHP), pulsed electrical fields, high pressure homogenisation, UV decont...

  1. 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.

  2. 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.

  3. 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.

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

    Indian Academy of Sciences (India)

    Growth and high pressure studies of zirconium sulphoselenide single ... tance was monitored in a Bridgman opposed anvil set-up up to 8 GPa pressure to identify .... The optical band gaps of the as-grown crystals were obtained by optical ab-.

  5. 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...

  6. High pressure phases of terbium: Possibility of a thcp phase

    International Nuclear Information System (INIS)

    Staun Olsen, J.; Steenstrup, S.; Gerward, L.

    1985-01-01

    High pressure phases of trivalent Tb studied by energy dispersive X-ray diffraction with synchrotron radiation exhibits the closed packed sequence (hcp -> Sm -> dhcp -> fcc) typical of the trivalent rare earth metals. Furthermore, a phase consistent with a triple hexagonal closed packed (thcp) structure was observed in a narrow pressure range around 30 GPa. (orig.)

  7. 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.

  8. 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.

  9. 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.

  10. 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.

  11. High pressure structural studies on nanophase praseodymium oxide

    International Nuclear Information System (INIS)

    Saranya, L.; Chandra Shekar, N.V.; Amirthapandian, S.; Hussain, Shamima; Arulraj, A.; Sahu, P. Ch.

    2014-01-01

    The phase stability of nanocrystalline Pr 2 O 3 has been investigated under pressure by in-situ high pressure X-ray diffraction using Mao-Bell type diamond anvil cell. The ambient structure and phase of the praseodymium oxide have been resolved unambiguously using x-ray diffraction, SEM and TEM techniques. Under the action of pressure the cubic phase of the system is retained up to 15 GPa. This is unusual as other isostructural rare earth oxides show structural transformations even at lower pressures. From the best fit to the P–V data with the Murnaghan equation of state yields a bulk modulus of 171 GPa

  12. High-pressure structural behaviour of nanocrystalline Ge

    International Nuclear Information System (INIS)

    Wang, H; Liu, J F; He, Y; Wang, Y; Chen, W; Jiang, J Z; Olsen, J Staun; Gerward, L

    2007-01-01

    The equation of state and the pressure of the I-II transition have been studied for nanocrystalline Ge using synchrotron x-ray diffraction. The bulk modulus and the transition pressure increase with decreasing particle size for both Ge-I and Ge-II, but the percentage volume collapse at the transition remains constant. Simplified models for the high-pressure structural behaviour are presented, based on the assumption that a large fraction of the atoms reside in grain boundary regions of the nanocrystalline material. The interface structure plays a significant role in affecting the transition pressure and the bulk modulus

  13. Trends in high pressure developments for new perspectives

    Science.gov (United States)

    Largeteau, Alain; Prakasam, Mythili

    2018-06-01

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

  14. Some neutronics of innovative subcritical assembly with fast neutron spectrum

    International Nuclear Information System (INIS)

    Kiyavitskaya, H.; Fokov, Yu.; Rutkovskaya, Ch.; Sadovich, S.; Kasuk, D.; Gohar, Y.; Bolshinsky, I.

    2013-01-01

    Conclusion: • New assembly can be used to: • develop the experimental techniques and adapt the existing ones for monitoring the sub-criticality level, neutron spectra measurements, etc; • study the spatial kinetics of sub-critical and critical systems with fast neutron spectra; • measure the transmutation reaction rates of minor-actinides etc

  15. Choosing the optimal parameters of subcritical reactors driven by accelerators

    International Nuclear Information System (INIS)

    Khudaverdyan, A.G.; Zhamkochyan, V.M.

    1998-03-01

    Physical aspects of a subcritical Nuclear Power Plants (NPP) driven by proton accelerators are considered. Estimated theoretical calculations are made for subcritical regimes of various types of reactors. It was shown that the creation of the quite effective explosion-safe NPP is real at an existing level of the accelerator technique by using available reactor units (including the serial ones). (author)

  16. High-pressure behavior of CaMo O4

    Science.gov (United States)

    Panchal, V.; Garg, N.; Poswal, H. K.; Errandonea, D.; Rodríguez-Hernández, P.; Muñoz, A.; Cavalli, E.

    2017-09-01

    We report a high-pressure study of tetragonal scheelite-type CaMo O4 up to 29 GPa. In order to characterize its high-pressure behavior, we have combined Raman and optical-absorption measurements with density functional theory calculations. We have found evidence of a pressure-induced phase transition near 15 GPa. Experiments and calculations agree in assigning the high-pressure phase to a monoclinic fergusonite-type structure. The reported results are consistent with previous powder x-ray-diffraction experiments, but are in contradiction with the conclusions obtained from earlier Raman measurements, which support the existence of more than one phase transition in the pressure range covered by our studies. The observed scheelite-fergusonite transition induces significant changes in the electronic band gap and phonon spectrum of CaMo O4 . We have determined the pressure evolution of the band gap for the low- and high-pressure phases as well as the frequencies and pressure dependencies of the Raman-active and infrared-active modes. In addition, based on calculations of the phonon dispersion of the scheelite phase, carried out at a pressure higher than the transition pressure, we propose a possible mechanism for the reported phase transition. Furthermore, from the calculations we determined the pressure dependence of the unit-cell parameters and atomic positions of the different phases and their room-temperature equations of state. These results are compared with previous experiments showing a very good agreement. Finally, information on bond compressibility is reported and correlated with the macroscopic compressibility of CaMo O4 . The reported results are of interest for the many technological applications of this oxide.

  17. 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.

  18. Promotion or suppression of glucose isomerization in subcritical aqueous straight- and branched-chain alcohols.

    Science.gov (United States)

    Gao, Da-Ming; Kobayashi, Takashi; Adachi, Shuji

    2015-01-01

    The influence of water-miscible alcohols (methanol, 1-propanol, 2-propanol, and t-butyl alcohol) on the isomerization of glucose to fructose and mannose was investigated under subcritical aqueous conditions (180-200 °C). Primary and secondary alcohols promoted the conversion and isomerization of glucose to afford fructose and mannose with high and low selectivity, respectively. On the other hand, the decomposition (side-reaction) of glucose was suppressed in the presence of the primary and secondary alcohols compared with that in subcritical water. The yield of fructose increased with increasing concentration of the primary and secondary alcohols, and the species of the primary and secondary alcohols tested had little effect on the isomerization behavior of glucose. In contrast, the isomerization of glucose was suppressed in subcritical aqueous t-butyl alcohol. Both the conversion of glucose and the yield of fructose decreased with increasing concentration of t-butyl alcohol. In addition, mannose was not detected in reactions using subcritical aqueous t-butyl alcohol.

  19. Experimental study of elliptical jet from supercritical to subcritical conditions using planar laser induced fluorescence

    Energy Technology Data Exchange (ETDEWEB)

    Muthukumaran, C. K.; Vaidyanathan, Aravind, E-mail: aravind7@iist.ac.in [Department of Aerospace Engineering, Indian Institute of Space Science and Technology, Trivandrum, Kerala 695547 (India)

    2015-03-15

    The study of fluid jet dynamics at supercritical conditions involves strong coupling between fluid dynamic and thermodynamic phenomena. Beyond the critical point, the liquid-vapor coexistence ceases to exist, and the fluid exists as a single phase known as supercritical fluid with its properties that are entirely different from liquids and gases. At the critical point, the liquids do not possess surface tension and latent heat of evaporation. Around the critical point, the fluid undergoes large changes in density and possesses thermodynamic anomaly like enhancement in thermal conductivity and specific heat. In the present work, the transition of the supercritical and near-critical elliptical jet into subcritical as well as supercritical environment is investigated experimentally with nitrogen and helium as the surrounding environment. Under atmospheric condition, a liquid jet injected from the elliptical orifice exhibits axis switching phenomena. As the injection temperature increases, the axis switching length also increases. Beyond the critical temperature, the axis switching is not observed. The investigation also revealed that pressure plays a major role in determining the thermodynamic transition of the elliptical jet only for the case of supercritical jet injected into subcritical chamber conditions. At larger pressures, the supercritical jet undergoes disintegration and formation of droplets in the subcritical environment is observed. However, for supercritical jet injection into supercritical environment, the gas-gas like mixing behavior is observed.

  20. Experimental study of elliptical jet from supercritical to subcritical conditions using planar laser induced fluorescence

    International Nuclear Information System (INIS)

    Muthukumaran, C. K.; Vaidyanathan, Aravind

    2015-01-01

    The study of fluid jet dynamics at supercritical conditions involves strong coupling between fluid dynamic and thermodynamic phenomena. Beyond the critical point, the liquid-vapor coexistence ceases to exist, and the fluid exists as a single phase known as supercritical fluid with its properties that are entirely different from liquids and gases. At the critical point, the liquids do not possess surface tension and latent heat of evaporation. Around the critical point, the fluid undergoes large changes in density and possesses thermodynamic anomaly like enhancement in thermal conductivity and specific heat. In the present work, the transition of the supercritical and near-critical elliptical jet into subcritical as well as supercritical environment is investigated experimentally with nitrogen and helium as the surrounding environment. Under atmospheric condition, a liquid jet injected from the elliptical orifice exhibits axis switching phenomena. As the injection temperature increases, the axis switching length also increases. Beyond the critical temperature, the axis switching is not observed. The investigation also revealed that pressure plays a major role in determining the thermodynamic transition of the elliptical jet only for the case of supercritical jet injected into subcritical chamber conditions. At larger pressures, the supercritical jet undergoes disintegration and formation of droplets in the subcritical environment is observed. However, for supercritical jet injection into supercritical environment, the gas-gas like mixing behavior is observed

  1. Steady squares and hexagons on a subcritical ramp

    International Nuclear Information System (INIS)

    Hoyle, R.B.

    1995-01-01

    Steady squares and hexagons on a subcritical ramp are studied, both analytically and numerically, within the framework of the lowest-order amplitude equations. On the subcritical ramp, the external stress or control parameter varies continuously in space from subcritical to supercritical values. At the subcritical end of the ramp, pattern formation is suppressed, and patterns fade away into the conduction solution. It is shown that three-dimensional patterns may change shape on a subcritical ramp. A square pattern becomes a pattern of rolls as it fades, with the roll axes aligned in the direction orthogonal to that in which the control parameter varies. Hexagons in systems with horizontal midplane symmetry become a pattern of rectangles before reaching the conduction solution. There is a suggestion that hexagons in systems which lack this symmetry might fade away through a roll pattern. Numerical simulations are used to illustrate these phenomena

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

    Energy Technology Data Exchange (ETDEWEB)

    Corno, Ada del, E-mail: delcorno@rse-web.it [RSE, Power Generation Technologies and Materials Dept, via Rubattino 54, I-20134 Milano (Italy); Morandi, Sonia, E-mail: morandi@rse-web.it [RSE, Power Generation Technologies and Materials Dept, via Rubattino 54, I-20134 Milano (Italy); Parozzi, Flavio, E-mail: parozzi@rse-web.it [RSE, Power Generation Technologies and Materials Dept, via Rubattino 54, I-20134 Milano (Italy); Araneo, Lucio, E-mail: lucio.araneo@polimi.it [Politecnico di Milano, Department of Energy, via Lambruschini 4A, I-20156 Milano (Italy); CNR-IENI, via Cozzi 53, I-20125 Milano (Italy); Casella, Francesco, E-mail: francesco2.casella@mail.polimi.it [Politecnico di Milano, Department of Energy, via Lambruschini 4A, I-20156 Milano (Italy)

    2017-01-15

    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{sub 2} particles with sizes 0.5 or 1.0 μm and initial concentration in the range 2–90 mg/m{sup 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{sub 2} particles with sizes 0.5 or 1.0 μm and initial concentration ranging between 2 and 99 mg/m{sup 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

  3. 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

  4. 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.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2011-05-15

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

  6. Subcritical limits for special fissile actinides

    International Nuclear Information System (INIS)

    Clark, H.K.

    1980-01-01

    Critical masses and subcritical mass limits in oxide-water mixtures were calculated for actinide nuclides other than 233 U, 235 U, and 239 Pu that have an odd number of neutrons in the nucleus: S/sub n/ transport theory was used together with cross sections, drawn from the GLASS multigroup library, developed to provide accurate forecasts of actinide production at Savannah River. The subcritical limits are 201 g for 241 Pu, 13 g for 242 /sup m/Am, 90 g for 243 Cm, 30 g for 245 Cm, 900 g for 247 Cm, 10 g for 249 Cf, and 5 g for 251 Cf. Association of 241 Pu with an equal mass of 240 Pu increases the 241 Pu limit to a value greater than that for pure 239 Pu. Association of 242 /sup m/Am with 241 Am increases the limit for the mixture to that for dry, theoretical density AmO 2 at isotopic concentrations of 242 /sup m/Am less than approx. 6%. Association of 245 Cm with 244 Cm increases the limit according to the formula 30 + 0.3 244 Cm/ 245 Cm up to the limit for dry CmO 2 . A limiting mass of 8.15 kg for plutonium containing at least 67% 238 Pu as oxide was calculated that applies (provided 240 Pu exceeds 241 Pu) with no limit on moderation. 1 figure, 5 tables

  7. Criticality Analysis of SAMOP Subcritical Assembly

    International Nuclear Information System (INIS)

    Tegas-Sutondo; Syarip; Triwulan-Tjiptono

    2005-01-01

    A critically analysis has been performed for homogenous system of uranyl nitrate solution, as part of a preliminary design assessment on neutronic aspect of SAMOP sub-critical assembly. The analysis is intended to determine some critical parameters such as the minimum of critical dimension and critical mass for the desired concentration. As the basis of this analysis, it has been defined a fuel system with an enrichment of 20% for cylindrical geometry of both bare and graphite reflected of 30 cm thickness. The MCNP code has been utilized for this purpose, for variation of concentrations ranging from 150 g/l to 500 g/l. It is found that the best concentration giving the minimum geometrical dimension is around 400 g/l, for both the bare and reflected systems. Whilst the best one, of minimum critical mass is corresponding to the concentration of around 200 g/l with critical mass around 14.1 kg and 4.2 kg for the bare and reflected systems respectively. Based on the result of calculations, it is concluded that by taking into consideration of the critical limit, the SAMOP subcritical assembly is neutronically can be made. (author)

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

    Science.gov (United States)

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

    2014-08-07

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

  9. Baking and coking properties of hard coal under high pressure

    Energy Technology Data Exchange (ETDEWEB)

    Beyer, H.D.

    1981-09-01

    For a better assessment of the baking and coking properties of hard coal under high pressure as in modern coal beneficiation processes, the determination of the swelling index and the dilatation curve are investigated.

  10. 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,

  11. 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 ...

  12. 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...

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

    African Journals Online (AJOL)

    bmshsj

    2011-11-02

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

  14. 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.

  15. Electronic structure and optical properties of AIN under high pressure

    International Nuclear Information System (INIS)

    Li Zetao; Dang Suihu; Li Chunxia

    2011-01-01

    We have calculated the electronic structure and optical properties of Wurtzite structure AIN under different high pressure with generalized gradient approximation (GGA) in this paper. The total energy, density of state, energy band structure and optical absorption and reflection properties under high pressure are calculated. By comparing the changes of the energy band structure, we obtained AIN phase transition pressure for 16.7 GPa, which is a direct band structure transforming to an indirect band structure. Meanwhile, according to the density of states distribution and energy band structure, we analyzed the optical properties of AIN under high-pressure, the results showed that the absorption spectra moved from low-energy to high-energy. (authors)

  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. 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

  18. 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)

  19. 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

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

    Science.gov (United States)

    Buckow, Roman; Sikes, Anita; Tume, Ron

    2013-01-01

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

  1. 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

  2. Very high pressure Moessbauer spectroscopy using diamond anvil cells

    International Nuclear Information System (INIS)

    Pasternak, M.P.; Taylor, R.D.

    1988-01-01

    The technique of generating very high pressure by means of Diamond Anvil Cells (DAC) for Mossbauer Effect applications is outlined. A comprehensive description is presented of the principles of DAC, modification for the use in M/umlt o/ssbauer Spectroscopy (MS), the Merrill--Bassett and Bassett cells, of pressure measurements, of gasketing and collimation, and of hydrostatic media. Examples of 151 Eu, 119 Sn and 129 I are given showing the feasibility of DAC applications in MS. Other isotopes with potential use for high pressure MS using DAC are suggested. 27 refs., 9 figs

  3. High pressure processing's potential to inactivate norovirus and other fooodborne viruses

    Science.gov (United States)

    High pressure processing (HPP) can inactivate human norovirus. However, all viruses are not equally susceptible to HPP. Pressure treatment parameters such as required pressure levels, initial pressurization temperatures, and pressurization times substantially affect inactivation. How food matrix ...

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

    Science.gov (United States)

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

    2018-06-01

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

  5. International conference on sub-critical accelerator driven systems. Proceedings

    International Nuclear Information System (INIS)

    Litovkina, L.P.; Titarenko, Yu.E.

    1999-01-01

    The International Meeting on Sub-Critical Accelerator Driven Systems was organized by the State Scientific Center - Institute for Theoretical and Experimental Physics with participation of Atomic Ministry of RF. The Meeting objective was to analyze the recent achievements and tendencies of the accelerator-driven systems development. The Meeting program covers a broad range of problems including the accelerator-driven systems (ADS) conceptual design; analyzing the ADS role in nuclear fuel cycle; accuracy of modeling the main parameters of ADS; conceptual design of high-current accelerators. Moreover, the results of recent experimental and theoretical studies on nuclear data accumulation to support the ADS technologies are presented. About 70 scientists from the main scientific centers of Russia, as well as scientists from USA, France, Belgium, India, and Yugoslavia, attended the meeting and presented 44 works [ru

  6. 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.

  7. 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.

  8. High pressure synthesis of amorphous TiO2 nanotubes

    Directory of Open Access Journals (Sweden)

    Quanjun Li

    2015-09-01

    Full Text Available Amorphous TiO2 nanotubes with diameters of 8-10 nm and length of several nanometers were synthesized by high pressure treatment of anatase TiO2 nanotubes. The structural phase transitions of anatase TiO2 nanotubes were investigated by using in-situ high-pressure synchrotron X-ray diffraction (XRD method. The starting anatase structure is stable up to ∼20GPa, and transforms into a high-density amorphous (HDA form at higher pressure. Pressure-modified high- to low-density transition was observed in the amorphous form upon decompression. The pressure-induced amorphization and polyamorphism are in good agreement with the previous results in ultrafine TiO2 nanoparticles and nanoribbons. The relationship between the LDA form and α-PbO2 phase was revealed by high-resolution transmission electron microscopy (HRTEM study. In addition, the bulk modulus (B0 = 158 GPa of the anatase TiO2 nanotubes is smaller than those of the corresponding bulks and nanoparticles (180-240 GPa. We suggest that the unique open-ended nanotube morphology and nanosize play important roles in the high pressure phase transition of TiO2 nanotubes.

  9. 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.

  10. 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.

  11. Experimental aspects of buoyancy correction in measuring reliable high-pressure excess adsorption isotherms using the gravimetric method

    Science.gov (United States)

    Nguyen, Huong Giang T.; Horn, Jarod C.; Thommes, Matthias; van Zee, Roger D.; Espinal, Laura

    2017-12-01

    Addressing reproducibility issues in adsorption measurements is critical to accelerating the path to discovery of new industrial adsorbents and to understanding adsorption processes. A National Institute of Standards and Technology Reference Material, RM 8852 (ammonium ZSM-5 zeolite), and two gravimetric instruments with asymmetric two-beam balances were used to measure high-pressure adsorption isotherms. This work demonstrates how common approaches to buoyancy correction, a key factor in obtaining the mass change due to surface excess gas uptake from the apparent mass change, can impact the adsorption isotherm data. Three different approaches to buoyancy correction were investigated and applied to the subcritical CO2 and supercritical N2 adsorption isotherms at 293 K. It was observed that measuring a collective volume for all balance components for the buoyancy correction (helium method) introduces an inherent bias in temperature partition when there is a temperature gradient (i.e. analysis temperature is not equal to instrument air bath temperature). We demonstrate that a blank subtraction is effective in mitigating the biases associated with temperature partitioning, instrument calibration, and the determined volumes of the balance components. In general, the manual and subtraction methods allow for better treatment of the temperature gradient during buoyancy correction. From the study, best practices specific to asymmetric two-beam balances and more general recommendations for measuring isotherms far from critical temperatures using gravimetric instruments are offered.

  12. Diamonds: powerful tools for high-pressure physics

    International Nuclear Information System (INIS)

    Anon.

    1983-01-01

    Diamond-anvil high-pressure studies have progressed to the point where they complement shock-wave studies. Because they operate at static high pressure, they permit time-consuming procedures, such as x-ray diffraction measurements for determining crystal structure. The sample material is completely recoverable and the method is adaptable to minute advantage when dealing with rare or hazardous materials. One of our goals in investigating the high-pressure behavior of iridium was to test the theoretical prediction that iridium would exhibit a phase transformation from the face-centered cubic crystal structure at about 9 GPa. Our finding that no such transformation takes place even at pressures up to 30 GPa will need to be taken into account by physicsts working to improve solid-state theory

  13. 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.

  14. Modification of enzymes by use of high-pressure homogenization.

    Science.gov (United States)

    Dos Santos Aguilar, Jessika Gonçalves; Cristianini, Marcelo; Sato, Helia Harumi

    2018-07-01

    High-pressure is an emerging and relatively new technology that can modify various molecules. High-pressure homogenization (HPH) has been used in several studies on protein modification, especially in enzymes used or found in food, from animal, plant or microbial resources. According to the literature, the enzymatic activity can be modulated under pressure causing inactivation, stabilization or activation of the enzymes, which, depending on the point of view could be very useful. Homogenization can generate changes in the structure of the enzyme modifying various chemical bonds (mainly weak bonds) causing different denaturation levels and, consequently, affecting the catalytic activity. This review aims to describe the various alterations due to HPH treatment in enzymes, to show the influence of high-pressure on proteins and to report the HPH effects on the enzymatic activity of different enzymes employed in the food industry and research. Copyright © 2018 Elsevier Ltd. All rights reserved.

  15. 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.

  16. 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.

  17. Performance characterization of solid oxide cells under high pressure

    DEFF Research Database (Denmark)

    Sun, Xiufu; Bonaccorso, Alfredo Damiano; Graves, Christopher R.

    2014-01-01

    in both fuel cell mode and electrolysis mode. In electrolysis mode at low current density, the performance improvement was counteracted by the increase in open circuit voltage, but it has to be born in mind that the pressurised gas contains higher molar free energy. Operating at high current density...... hydrocarbon fuels, which is normally performed at high pressure to achieve a high yield. Operation of SOECs at elevated pressure will therefore facilitate integration with the downstream fuel synthesis and is furthermore advantageous as it increases the cell performance. In this work, recent pressurised test...... results of a planar Ni-YSZ (YSZ: Yttria stabilized Zirconia) supported solid oxide cell are presented. The test was performed at 800 °C at pressures up to 15 bar. A comparison of the electrochemical performance of the cell at 1 and 3 bar shows a significant and equal performance gain at higher pressure...

  18. 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

  19. 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...

  20. Effect of high pressure hydrogen on low-cycle fatigue

    International Nuclear Information System (INIS)

    Rie, K.T.; Kohler, W.

    1979-01-01

    It has been shown that the fatigue life can be influenced in low-cycle range by high pressure hydrogen while the effect of high pressure hydrogen on high-cycle fatigue will not be as significant. The paper reports the details and the results of the investigations of the effect of high pressure hydrogen on the low-cycle endurance of commercially pure titanium. The results of this study indicate that: 1. The degradation of the fatigue life in low-cycle region for commercially pure titanium under high pressure hydrogen can be described by Nsub(cr)sup(α x Δepsilon)sub(pl)sup(=c) 2. The fatigue life decreases with decreasing strain rate. 3. The fatigue life decreases with increasing hydrogen pressure. It was found that the semilogarithmic plot of the fatigue life versus the hydrogen pressure gives a linear relationship. The Sievert's law does not hold in low-cycle fatigue region. 4. HAC in titanium in low-cycle fatigue region is the result of the disolution of hydrogen at the crack tip and of the strain-induced hybride formation. (orig.) 891 RW/orig. 892 RKD [de

  1. 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)

  2. High-pressure tolerance of earthworm fibrinolytic and digestive enzymes.

    Science.gov (United States)

    Akazawa, Shin-Ichi; Tokuyama, Haruka; Sato, Shunsuke; Watanabe, Toshinori; Shida, Yosuke; Ogasawara, Wataru

    2018-02-01

    Earthworms contain several digestive and therapeutic enzymes that are beneficial to our health and useful for biomass utilization. Specifically, earthworms contain potent fibrinolytic enzymes called lumbrokinases, which are highly stable even at room temperature and remain active in dried earthworm powder. However, the high-temperature sterilization method leads to the inactivation of enzymes. Therefore, we investigated the effect of high-pressure treatment (HPT) (from 0.1 MPa to 500 MPa at 25°C and 50°C) on the enzymatic activity of lumbrokinase (LK), α-amylase (AMY), endoglucanase (EG), β-glucosidase (BGL), and lipase (LP) of the earthworm Eisenia fetida, Waki strain, and its sterilization ability in producing dietary supplement. LK showed thermo- and high-pressure tolerance. In addition, HPT may have resulted in pressure-induced stabilization and activation of LK. Although AMY activity was maintained up to 400 MPa at 25°C, the apparent activity decreased slightly at 50°C with HPT. EG showed almost the same pattern as AMY. However, it is possible that the effects of temperature and pressure compensated each other under 100 MPa at 50°C. BGL was shown to be a pressure- and temperature-sensitive enzyme, and LP showed a thermo- and high-pressure tolerance. The slight decrease in apparent activity occurred under 200 MPa at both temperatures. Furthermore, the low-temperature and pressure treatment completely sterilized the samples. These results provide a basis for the development of a novel earthworm dietary supplement with fibrinolytic and digestive activity and of high-pressure-tolerant enzymes to be used for biomass pretreatment. Copyright © 2017 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

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

    Science.gov (United States)

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

    2012-08-01

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

  4. 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)

  5. 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)

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

    DEFF Research Database (Denmark)

    Varzandeh, Farhad

    properties like saturation pressures, densities at reservoir temperature and Stock TankviOil (STO) densities, while keeping the n-alkane limit of the correlations unchanged. Apart from applying this general approach to PC-SAFT, we have also shown that the approach can be applied to classical cubic models...... approach to characterizing reservoir fluids for any EoS. The approach consists in developing correlations of model parameters first with a database for well-defined components and then adjusting the correlations with a large PVT database. The adjustment is made to minimize the deviation in key PVT...... method to SRK and PR improved the saturation pressure calculation in comparisonto the original characterization method for SRK and PR. Using volume translationtogether with the new characterization approach for SRK and PR gives comparable results for density and STO density to that of original...

  7. 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.

  8. 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.

  9. Subcritical water extraction of phenolic and antioxidant constituents from pistachio (Pistacia vera L.) hulls.

    Science.gov (United States)

    Erşan, Sevcan; Güçlü Üstündağ, Özlem; Carle, Reinhold; Schweiggert, Ralf M

    2018-07-01

    Pistachio hulls, important by-products of pistachio processing, were extracted using an environmentally friendly process with subcritical water (SCW) at a pressure of 6.9 MPa in the range of 110 and 190 °C, and a flow rate of 4 ml/min. Detailed HPLC-DAD-ESI/MS n analyses allowed the identification of 49 phenolic compounds in the SCW extracts. Total gallotannin yields up to 33 g/kg were reached at 150-170 °C, where gallic acid (22.2 g/kg) and penta-O-galloyl-β-d-glucose (9.77 g/kg) levels were 13.2- and 10.6-fold higher than those in the aqueous methanol extracts. Flavonols were also effectively extracted at 110-150 °C (4.37-5.65 g/kg), while anacardic acid recovery was poor (1.13-2.77 g/kg). Accordingly, high amounts of anacardic acids (up to 50.7 g/kg) were retained in the extraction residue, revealing that SCW extraction allowed selective extraction of gallotannins and flavonols. Antioxidant capacities ranged from 0.68 to 1.20 mmol Trolox equivalents (TE)/g for SCW extracts increasing with temperature up 190 °C. Copyright © 2018 Elsevier Ltd. All rights reserved.

  10. Fusion-driven sub-critical dual-cooled waste transmutation blanket: design and analysis

    International Nuclear Information System (INIS)

    Wang Weihua; Wu Yican; Ke Yan; Kang Zhicheng; Wang Hongyan; Huang Qunying

    2003-01-01

    The Fusion-Driven Sub-critical System (FDS) is one of the Chinese programs to be further developed for fusion application. Its Dual-cooled Waste Transmutation Blanket (DWTB), as one the most important part of the FDS is cooled by helium and liquid metal, and have the features of safety, tritium self-sustaining, high efficiency and feasibility. Its conceptual design has been finished. This paper is mainly involved with the basic structure design and thermal-hydraulics analysis of DWTB. On the basis of a three-dimensional (3-D) model of radial-toroidal sections of the segment box, thermal temperature gradients and structure analysis made with a comprehensive finite element method (FEM) have been performed with the computer code ANSYS5.7 and computational fluid dynamic finite element codes. The analysis refers to the steady-state operating condition of an outboard blanket segment. Furthermore, the mechanical loads due to coolant pressure in normal operating conditions have been also taken into account. All the above loads have been combined as an input for a FEM stress analysis and the resulting stress distribution has been evaluated. Finally, the structure design and Pb-17Li flow velocity has been optimized according to the calculations and analysis

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2017-01-15

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

  12. 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...

  13. 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...

  14. Strength-toughness requirements for thick walled high pressure vessels

    International Nuclear Information System (INIS)

    Kapp, J.A.

    1990-01-01

    The strength and toughness requirements of materials for use in high pressure vessels has been the subject of some discussion in the meetings of the Materials Task Group of the Special Working Group High Pressure Vessels. A fracture mechanics analysis has been performed to theoretically establish the required toughness for a high pressure vessel. This paper reports that the analysis performed is based on the validity requirement for plane strain fracture of fracture toughness test specimens. This is that at the fracture event, the crack length, uncracked ligament, and vessel length must each be greater than fifty times the crack tip plastic zone size for brittle fracture to occur. For high pressure piping applications, the limiting physical dimension is the uncracked ligament, as it can be assumed that the other dimensions are always greater than fifty times the crack tip plastic zone. To perform the fracture mechanics analysis several parameters must be known: these include vessel dimensions, material strength, degree of autofrettage, and design pressure. Results of the analysis show, remarkably, that the effects of radius ratio, pressure and degree of autofrettage can be ignored when establishing strength and toughness requirements for code purposes. The only parameters that enter into the calculation are yield strength, toughness and vessel thickness. The final results can easily be represented as a graph of yield strength against toughness on which several curves, one for each vessel thickness, are plotted

  15. Characterization of high-pressure, underexpanded hydrogen-jet flames

    Energy Technology Data Exchange (ETDEWEB)

    Schefer, R.W.; Houf, W.G.; Williams, T.C. [Combustion Research Facility, Sandia National Laboratories, Livermore, CA 94551 (United States); Bourne, B.; Colton, J. [SRI International, 333 Ravenwood Ave., Menlo Park, CA 94025 (United States)

    2007-08-15

    Measurements were performed to characterize the dimensional and radiative properties of large-scale, vertical hydrogen-jet flames. This data is relevant to the safety scenario of a sudden leak in a high-pressure hydrogen containment vessel and will provide a technological basis for determining hazardous length scales associated with unintended hydrogen releases at storage and distribution centers. Jet flames originating from high-pressure sources up to 413 bar (6000 psi) were studied to verify the application of correlations and scaling laws based on lower-pressure subsonic and choked-flow jet flames. These higher pressures are expected to be typical of the pressure ranges in future hydrogen storage vessels. At these pressures the flows exiting the jet nozzle are categorized as underexpanded jets in which the flow is choked at the jet exit. Additionally, the gas behavior departs from that of an ideal-gas and alternate formulations for non-ideal gas must be introduced. Visible flame emission was recorded on video to evaluate flame length and structure. Radiometer measurements allowed determination of the radiant heat flux characteristics. The flame length results show that lower-pressure engineering correlations, based on the Froude number and a non-dimensional flame length, also apply to releases up to 413 bar (6000 psi). Similarly, radiative heat flux characteristics of these high-pressure jet flames obey scaling laws developed for low-pressure, smaller-scale flames and a wide variety of fuels. The results verify that such correlations can be used to a priori predict dimensional characteristics and radiative heat flux from a wide variety of hydrogen-jet flames resulting from accidental releases. (author)

  16. 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

  17. Photoconductivity studies of the ferrocyanide ion under high pressure

    Energy Technology Data Exchange (ETDEWEB)

    Finston, M. I.

    1979-01-01

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

  18. 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.

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

    Science.gov (United States)

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

    2010-02-01

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

  20. Microscopic Analysis of Bacterial Motility at High Pressure

    Science.gov (United States)

    Nishiyama, Masayoshi; Sowa, Yoshiyuki

    2012-01-01

    The bacterial flagellar motor is a molecular machine that converts an ion flux to the rotation of a helical flagellar filament. Counterclockwise rotation of the filaments allows them to join in a bundle and propel the cell forward. Loss of motility can be caused by environmental factors such as temperature, pH, and solvation. Hydrostatic pressure is also a physical inhibitor of bacterial motility, but the detailed mechanism of this inhibition is still unknown. Here, we developed a high-pressure microscope that enables us to acquire high-resolution microscopic images, regardless of applied pressures. We also characterized the pressure dependence of the motility of swimming Escherichia coli cells and the rotation of single flagellar motors. The fraction and speed of swimming cells decreased with increased pressure. At 80 MPa, all cells stopped swimming and simply diffused in solution. After the release of pressure, most cells immediately recovered their initial motility. Direct observation of the motility of single flagellar motors revealed that at 80 MPa, the motors generate torque that should be sufficient to join rotating filaments in a bundle. The discrepancy in the behavior of free swimming cells and individual motors could be due to the applied pressure inhibiting the formation of rotating filament bundles that can propel the cell body in an aqueous environment. PMID:22768943

  1. How to Prevent High Blood Pressure: MedlinePlus Health Topic

    Science.gov (United States)

    ... Spanish Understanding Blood Pressure Readings (American Heart Association) Weightlifting: Bad for Your Blood Pressure? (Mayo Foundation for ... High Blood Pressure High Blood Pressure in Pregnancy Nutrition Quitting Smoking Stress National Institutes of Health The ...

  2. High pressure fracturing in Colombia: a quantum leap

    Energy Technology Data Exchange (ETDEWEB)

    Velasquez, Juan C. [BP Exploration (United Kingdom); Gutierrez, Jim; Ham, Ernesto; Castro, Alberto [BJ Services Company (United States)

    2004-07-01

    Fracturing has become one of the most common stimulation and well completion techniques in petroleum production. Due to the deeper depths and high frac gradients encountered in some areas, various treatments have resulted in early screen outs or aborted operations due to insufficient rate limited by the available treating pressures. A state of the art technology and high pressure equipment including the largest frac pumps (rated at 2,700 hhp) in the world, were used in Colombian fields to overcome these limitations. The reliability of this equipment has allowed the treatment of these wells to operating pressures of up to 18,000 psi and rates in excess of 40 bpm, placing up to 400,000 lbs of bauxite. Bottom hole treating pressures of 25,000 psi also were reached. This paper describes the development of the fracture campaign and relates the jobs performed to date, including the results and lessons learned (author)

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

    International Nuclear Information System (INIS)

    Hu Anguang; Zhang Fan

    2011-01-01

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

  4. High-pressure needle interface for thermoplastic microfluidics.

    Science.gov (United States)

    Chen, C F; Liu, J; Hromada, L P; Tsao, C W; Chang, C C; DeVoe, D L

    2009-01-07

    A robust and low dead volume world-to-chip interface for thermoplastic microfluidics has been developed. The high pressure fluidic port employs a stainless steel needle inserted into a mating hole aligned to an embedded microchannel, with an interference fit used to increase pressure resistance. Alternately, a self-tapping threaded needle screwed into a mating hole is also demonstrated. In both cases, the flat bottom needle ports seat directly against the microchannel substrate, ensuring low interfacial dead volumes. Low dispersion is observed for dye bands passing the interfaces. The needle ports offer sufficient pull-out forces for applications such as liquid chromatography that require high internal fluid pressures, with the epoxy-free interfaces compatible with internal microchannel pressures above 40 MPa.

  5. Pressure Amplification Off High Impedance Barriers in DDT

    Energy Technology Data Exchange (ETDEWEB)

    Heatwole, Eric Mann [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Broilo, Robert M. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Kistle, Trevin Joseph [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Parker, Gary Robert Jr. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2018-04-23

    The Deflagration-to-Detonation Transition (DDT) in one-dimensional porous explosive, where combustion in an explosive transitions to detonation, can be described by the following model. This simplified model proceeds in five steps, as follows: 1) Ignition of the explosive, surface burning. 2) Convective burning, with the flame front penetrating through the porous network of the explosive. This proceeds until the pressure grows high enough to result in choked flow in the pores restricting the convective burn. 3) The choked flow results in the formation of a high-density compact of explosive. This compact is driven into undisturbed material by the pressure of the burning explosive. See Figure1. 4) The compression of the undisturbed porous explosive by the compact leads to the ignition of a compressive burn. This builds in pressure until a supported shock forms. 5) The shock builds in pressure until detonation occurs. See Figure 2 for an overview streak of the proceeding steps.

  6. High pressure transport properties of Yb2Cu9

    International Nuclear Information System (INIS)

    Spendeler, L.; Jaccard, D.; Sierro, J.; Flouquet, J.

    1992-01-01

    The electrical resistivity (ρ) and the absolute thermopower (S) of high-purity Yb 2 Cu 9 have been measured between 1.2 and 300 K at pressures up to 17 kbar and in magnetic fields up to 6 T. At zero pressure the three measured samples show a Kondo peak in the resistivity at 17 K. Furthermore for one of them the resistivity rises below 5 K. Under pressure, the Kondo peak in ρ slowly moves towards lower temperatures indicating a decrease of the Kondo temperature T K , in good agreement with specific heat results. The increase of ρ below 5 K disappears completely for pressure lower than 1 kbar and the residual resistivity remains high. The thermopower S exhibits similar trends. Magnetic field dependences of both ρ and S are weak. No evidence of magnetic ordering has been detected up to 17.6 kbar

  7. Foam glass obtained through high-pressure sintering

    DEFF Research Database (Denmark)

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

    2018-01-01

    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...... 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...

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

    Science.gov (United States)

    Celebonovic, Vladan

    1992-09-01

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

  9. 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.

  10. Advances in high pressure research in condensed matter: proceedings of the international conference on condensed matter under high pressures

    International Nuclear Information System (INIS)

    Sikka, S.K.; Gupta, Satish C.; Godwal, B.K.

    1997-01-01

    The use of pressure as a thermodynamic variable for studying condensed matter has become very important in recent years. Its main effect is to reduce the volume of a substance. Thus, in some sense, it mimics the phenomena taking place during the cohesion of solids like pressure ionization, modifications in electronic properties and phase changes etc. Some of the phase changes under pressure lead to synthesis of new materials. The recent discovery of high T c superconductivity in YBa 2 Cu 3 O 7 may be indirectly attributed to the pressure effect. In applied fields like simulation of reactor accident, design of inertial confinement fusion schemes and for understanding the rock mechanical effects of shock propagation in earth due to underground nuclear explosions, the pressure versus volume relations of condensed matter are a vital input. This volume containing the proceedings of the International Conference on Condensed Matter Under High Pressure covers various aspects of high pressure pertaining to equations of state, phase transitions, electronic, optical and transport properties of solids, atomic and molecular studies, shock induced reactions, energetic materials, materials synthesis, mineral physics, geophysical and planetary sciences, biological applications and food processing and advances in experimental techniques and numerical simulations. Papers relevant to INIS are indexed separately

  11. Bias in calculated keff from subcritical measurements by the 252Cf-source-driven noise analysis method

    International Nuclear Information System (INIS)

    Mihalczo, J.T.; Valentine, T.E.

    1995-01-01

    The development of MCNP-DSP, which allows direct calculation of the measured time and frequency analysis parameters from subcritical measurements using the 252 Cf-source-driven noise analysis method, permits the validation of calculational methods for criticality safety with in-plant subcritical measurements. In addition, a method of obtaining the bias in the calculations, which is essential to the criticality safety specialist, is illustrated using the results of measurements with 17.771-cm-diam, enriched (93.15), unreflected, and unmoderated uranium metal cylinders. For these uranium metal cylinders the bias obtained using MCNP-DSP and ENDF/B-V cross-section data increased with subcriticality. For a critical experiment [height (h) = 12.629 cm], it was -0.0061 ± 0.0003. For a 10.16-cm-high cylinder (k ∼ 0.93), it was 0.0060 ± 0.0016, and for a subcritical cylinder (h = 8.13 cm, k ∼ 0.85), the bias was -0.0137 ± 0.0037, more than a factor of 2 larger in magnitude. This method allows the nuclear criticality safety specialist to establish the bias in calculational methods for criticality safety from in-plant subcritical measurements by the 252 Cf-source-driven noise analysis method

  12. High pressure phase transition in Pr-monopnictides

    Energy Technology Data Exchange (ETDEWEB)

    Raypuria, Gajendra Singh, E-mail: sosfizix@gmail.com, E-mail: gsraypuria@gmail.com; Gupta, Dinesh Chandra [Condensed Matter Theory Group, School of Studies in Physics, Jiwaji University, Gwalior - 474011 (India); Department of Physics, Govt. K.R.G. P.G. Autonomous College, Gwalior - 474001 (India)

    2015-06-24

    The Praseodymium-monopnictides compounds have been found to undergo transition from their initial NaCl-type structure to high pressure body centered tetragonal (BCT) structure (distorted CsCl-type P4/mmm) using CTIP model. The calculated values of cohesive energy, lattice constant, phase transition pressure, relative volume collapse agree well with the available measured data and better than those computed by earlier workers.

  13. Phase transition of La- chalcogenides under high pressure

    Energy Technology Data Exchange (ETDEWEB)

    Gupta, Dinesh Chandra [Condensed Matter Theory Group, School of Studies in Physics, Jiwaji University, Gwalior - 474 011 (India); Raypuria, Gajendra Singh, E-mail: gsraypuria@gmail.com [Department of Physics, Govt. K.R.G. P.G. Autonomous College, Gwalior - 474 001 (India)

    2014-04-24

    The lanthanum compounds have been found to undergo transition from their initial NaCl-type structure to high pressure body centered tetragonal (BCT) structure (distorted CsCl-type P4/mmm) using CTIP model. The calculated values of cohesive energy, lattice constant, phase transition pressure, relative volume collapse agree well with the available measured data and better than those computed by earlier workers.

  14. 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

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

    International Nuclear Information System (INIS)

    Park, Kwangheon; Yang, Sungwoo; Kim, Kyutae

    2005-01-01

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

  16. Massive subcritical compact arrays of plutonium metal

    Energy Technology Data Exchange (ETDEWEB)

    Rothe, R.E.

    1998-04-01

    Two experimental critical-approach programs are reported. Both were performed at the Rocky Flats Plant near Denver, Colorado; and both date back to the late 1960s. Both involve very large arrays of massive plutonium ingots. These ingots had been cast in the foundry at the Rocky Flats Plant as part of their routine production operations; they were not specially prepared for either study. Consequently, considerable variation in ingot mass is encountered. This mass varied between approximately 7 kg and a little more than 10 kg. One program, performed in the spring of 1969, involved stacked arrays of ingots contained within cylindrical, disk-shaped, thin, steel cans. This program studied four arrays defined by the pattern of steel cans in a single layer. The four were: 1 x N, 3 x N, 2 x 2 x N, and 3 x 3 x N. The second was a tightly-packed, triangular-pitched patterns; the last two were square-pitched patterns. The other program, performed about a year earlier, involved similar ingots also contained in similar steel cans, but these canned plutonium ingots were placed in commercial steel drums. This study pertained to one-, two-, and three-layered horizontal arrays of drums. All cases proved to be well subcritical. Most would have remained subcritical had the parameters of the array under study been continued infinitely beyond the reciprocal multiplication safety limit. In one case for the drum arrays, an uncertain extrapolation of the data of the earlier program suggests that criticality might have eventually been attained had several thousand additional kilograms of plutonium been available for use.

  17. Nonlinear dead water resistance at subcritical speed

    Science.gov (United States)

    Grue, John

    2015-08-01

    The dead water resistance F 1 = /1 2 C d w ρ S U 2 (ρ fluid density, U ship speed, S wetted body surface, Cdw resistance coefficient) on a ship moving at subcritical speed along the upper layer of a two-layer fluid is calculated by a strongly nonlinear method assuming potential flow in each layer. The ship dimensions correspond to those of the Polar ship Fram. The ship draught, b0, is varied in the range 0.25h0-0.9h0 (h0 the upper layer depth). The calculations show that Cdw/(b0/h0)2 depends on the Froude number only, in the range close to critical speed, Fr = U/c0 ˜ 0.875-1.125 (c0 the linear internal long wave speed), irrespective of the ship draught. The function Cdw/(b0/h0)2 attains a maximum at subcritical Froude number depending on the draught. Maximum Cdw/(b0/h0)2 becomes 0.15 for Fr = 0.76, b0/h0 = 0.9, and 0.16 for Fr = 0.74, b0/h0 = 1, where the latter extrapolated value of the dead water resistance coefficient is about 60 times higher than the frictional drag coefficient and relevant for the historical dead water observations. The nonlinear Cdw significantly exceeds linear theory (Fr < 0.85). The ship generated waves have a wave height comparable to the upper layer depth. Calculations of three-dimensional wave patterns at critical speed compare well to available laboratory experiments. Upstream solitary waves are generated in a wave tank of finite width, when the layer depths differ, causing an oscillation of the force. In a wide ocean, a very wide wave system develops at critical speed. The force approaches a constant value for increasing time.

  18. Massive subcritical compact arrays of plutonium metal

    International Nuclear Information System (INIS)

    Rothe, R.E.

    1998-01-01

    Two experimental critical-approach programs are reported. Both were performed at the Rocky Flats Plant near Denver, Colorado; and both date back to the late 1960s. Both involve very large arrays of massive plutonium ingots. These ingots had been cast in the foundry at the Rocky Flats Plant as part of their routine production operations; they were not specially prepared for either study. Consequently, considerable variation in ingot mass is encountered. This mass varied between approximately 7 kg and a little more than 10 kg. One program, performed in the spring of 1969, involved stacked arrays of ingots contained within cylindrical, disk-shaped, thin, steel cans. This program studied four arrays defined by the pattern of steel cans in a single layer. The four were: 1 x N, 3 x N, 2 x 2 x N, and 3 x 3 x N. The second was a tightly-packed, triangular-pitched patterns; the last two were square-pitched patterns. The other program, performed about a year earlier, involved similar ingots also contained in similar steel cans, but these canned plutonium ingots were placed in commercial steel drums. This study pertained to one-, two-, and three-layered horizontal arrays of drums. All cases proved to be well subcritical. Most would have remained subcritical had the parameters of the array under study been continued infinitely beyond the reciprocal multiplication safety limit. In one case for the drum arrays, an uncertain extrapolation of the data of the earlier program suggests that criticality might have eventually been attained had several thousand additional kilograms of plutonium been available for use

  19. Modeling of the CTEx subcritical unit using MCNPX code

    International Nuclear Information System (INIS)

    Santos, Avelino; Silva, Ademir X. da; Rebello, Wilson F.; Cunha, Victor L. Lassance

    2011-01-01

    The present work aims at simulating the subcritical unit of Army Technology Center (CTEx) namely ARGUS pile (subcritical uranium-graphite arrangement) by using the computational code MCNPX. Once such modeling is finished, it could be used in k-effective calculations for systems using natural uranium as fuel, for instance. ARGUS is a subcritical assembly which uses reactor-grade graphite as moderator of fission neutrons and metallic uranium fuel rods with aluminum cladding. The pile is driven by an Am-Be spontaneous neutron source. In order to achieve a higher value for k eff , a higher concentration of U235 can be proposed, provided it safely remains below one. (author)

  20. 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.

  1. 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.

  2. 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

  3. Transient heating effects in high pressure Diesel injector nozzles

    International Nuclear Information System (INIS)

    Strotos, George; Koukouvinis, Phoevos; Theodorakakos, Andreas; Gavaises, Manolis; Bergeles, George

    2015-01-01

    Highlights: • Simulation of friction-induced heating in high pressure Diesel fuel injectors. • Injection pressures up to 3000 bar. • Simulations with variable fuel properties significantly affect predictions. • Needle motion affects flow and temperature fields. • Possible heterogeneous boiling as injection pressures increase above 2000 bar. - Abstract: The tendency of today’s fuel injection systems to reach injection pressures up to 3000 bar in order to meet forthcoming emission regulations may significantly increase liquid temperatures due to friction heating; this paper identifies numerically the importance of fuel pressurization, phase-change due to cavitation, wall heat transfer and needle valve motion on the fluid heating induced in high pressure Diesel fuel injectors. These parameters affect the nozzle discharge coefficient (C d ), fuel exit temperature, cavitation volume fraction and temperature distribution within the nozzle. Variable fuel properties, being a function of the local pressure and temperature are found necessary in order to simulate accurately the effects of depressurization and heating induced by friction forces. Comparison of CFD predictions against a 0-D thermodynamic model, indicates that although the mean exit temperature increase relative to the initial fuel temperature is proportional to (1 − C d 2 ) at fixed needle positions, it can significantly deviate from this value when the motion of the needle valve, controlling the opening and closing of the injection process, is taken into consideration. Increasing the inlet pressure from 2000 bar, which is the pressure utilized in today’s fuel systems to 3000 bar, results to significantly increased fluid temperatures above the boiling point of the Diesel fuel components and therefore regions of potential heterogeneous fuel boiling are identified

  4. HIGH HYDROSTATIC PRESSURE SYSTEMS USE IN FOOD INDUSTRY

    Directory of Open Access Journals (Sweden)

    Yahya TÜLEK

    2006-02-01

    Full Text Available Food preservation is a continuous fight against microorganisms spoiling the food or making it unsafe. The last decade, non-thermal inactivation techniques have been a major research issue, driven by an increased consumer demand for nutritious, fresh like food products with a high organoleptical quality and an acceptable shelf life. Investigated inactivation technologies are ionisation radiation, high hydrostatic pressure (HHP, pulsed electrical fields, high pressure homogenisation, UV decontamination, etc. Most research has focussed on HHP and is therefore discussed in detail here.

  5. 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

  6. 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.)

  7. Experimental studies on radiation effects under high pressure oxygen

    Energy Technology Data Exchange (ETDEWEB)

    Fujimura, E [Osaka Univ. (Japan). School of Dentistry

    1974-06-01

    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 /sup 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.

  8. 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.

  9. 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

  10. 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

  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. 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.

  13. 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)

  14. 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)

  15. 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

  16. Investigation of a high pressure oxy-coal process

    Energy Technology Data Exchange (ETDEWEB)

    Renz, U. [RWTH Aachen Univ. (Germany). Inst. of Heat and Mass Transfer

    2013-07-01

    A study was conducted to investigate the feasibility of an oxy-coal process, which is pressurized to a combustion pressure of 80 bar. At that pressure the water-vapor can be separated economically from the CO{sub 2}/H{sub 2}O flue gases, either by nucleate condensation or by condensation on cooled surfaces in condenser heat exchangers at a temperature of about 300 C. The heat of condensation can be recaptured to preheat the boiler feed water. So the number of economizers is drastically reduced compared to a conventional steam cycle. Another interesting feature of the high pressure oxy-coal process is the fact, that low rank coal with high moisture content can be fired. Such a process at a pressure of about 80 bar is currently investigated by Babcock, USA, as the ThermoEnergy Integrated Power System (TIPS) and will be analyzed in the present paper. A known disadvantage of the oxy-coal processes is the large recirculating flue gas stream to control the combustion temperature, and which need large pipes and heavy recirculation fans. This disadvantage could be avoided if instead of flue gas a part of the condensed water from the condenser heat exchangers is recirculated. Within the present study both types of processes have been simulated and for an electric power output of about 220 MW. Furthermore, results of CFD simulations of a pressurized 250 MW combustor with a single swirl burner and flue gas recirculation will be presented.

  17. Evaluation of high pressure Freon decontamination. I. Preliminary tests

    International Nuclear Information System (INIS)

    Rankin, W.N.

    1983-01-01

    High-pressure Freon blasting techniques are being evaluated for applications involving the removal of non-adherent radioactive particulate contamination at SRP. Very little waste is generated by this technique because the used Freon can be easily distilled and reused. One of the principle advantages of this technique is that decontaminated electrical equipment can be returned to service immediately without drying, unlike high-pressure water blasting techniques. Preliminary scoutin tests evaluating high-pressure Freon blasting for decontamination at SRP were carried out at Quadrex Co., Oak Ridge, TN, October 12 and 13. DWPF-type contamination (raw sludge plus volatiles) and separations area-type contamination (diluted boiling point (47.6 0 C) allow it to rapidly separate from higher boiling contaminants via distillation with filtration to remove particulate material, and distillation with condensation, the solvent may be recovered for indefinite reuse while reducing the radioactive waste to a minimum. 3 references, 5 figures, 6 tables

  18. Bonding pathways of high-pressure chemical transformations

    International Nuclear Information System (INIS)

    Hu Anguang; Zhang Fan

    2013-01-01

    A three-stage bonding pathway towards high-pressure chemical transformations from molecular precursors or intermediate states has been identified by first-principles simulations. With the evolution of principal stress tensor components in the response of chemical bonding to compressive loading, the three stages can be defined as the van der Waals bonding destruction, a bond breaking and forming reaction, and equilibrium of new bonds. The three-stage bonding pathway leads to the establishment of a fundamental principle of chemical bonding under compression. It reveals that during high-pressure chemical transformation, electrons moving away from functional groups follow anti-addition, collision-free paths to form new bonds in counteracting the local stress confinement. In applying this principle, a large number of molecular precursors were identified for high-pressure chemical transformations, resulting in new materials. (fast track communication)

  19. 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)

  20. 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

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

    International Nuclear Information System (INIS)

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

    1979-01-01

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

  2. 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.

  3. Thermopower measurement under high pressure using 'seesaw heating method'

    International Nuclear Information System (INIS)

    Hedo, M; Nakamura, D; Takaesu, Y; Yagasaki, K; Nakama, T; Fujiwara, T; Uchima, K

    2010-01-01

    We have developed a set-up with modified 'seesaw heating method' for the thermopower measurement under pressures P up to 3 GPa at the temperature range between 2 K and 300 K. By using this set-up, the thermopower and electrical resistivity of the single crystalline YbMn 2 Ge 2 under high pressure were measured with enough accuracy. S(T) curve shows the characteristic feature at the magnetic transition in all pressure range, while no evidence of the magnetic phase transition is observed in ρ(T) at P > 1.25 GPa. The measurement results indicate that the simultaneous measurement of the thermopower and electrical resistivity is a useful tool to study the pressure-induced phase transitions.

  4. 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.

  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. Hydrostatic Pressure Sensing with High Birefringence Photonic Crystal Fibers

    Science.gov (United States)

    Fávero, Fernando C.; Quintero, Sully M. M.; Martelli, Cicero; Braga, Arthur M.B.; Silva, Vinícius V.; Carvalho, Isabel C. S.; Llerena, Roberth W. A.; Valente, Luiz C. G.

    2010-01-01

    The effect of hydrostatic pressure on the waveguiding properties of high birefringence photonic crystal fibers (HiBi PCF) is evaluated both numerically and experimentally. A fiber design presenting form birefringence induced by two enlarged holes in the innermost ring defining the fiber core is investigated. Numerical results show that modal sensitivity to the applied pressure depends on the diameters of the holes, and can be tailored by independently varying the sizes of the large or small holes. Numerical and experimental results are compared showing excellent agreement. A hydrostatic pressure sensor is proposed and demonstrated using an in-fiber modal interferometer where the two orthogonally polarized modes of a HiBi PCF generate fringes over the optical spectrum of a broad band source. From the analysis of experimental results, it is concluded that, in principle, an operating limit of 92 MPa in pressure could be achieved with 0.0003% of full scale resolution. PMID:22163435

  7. High pressure structural studies on nanophase praseodymium oxide

    Energy Technology Data Exchange (ETDEWEB)

    Saranya, L. [Jamal Mohamed College, Tiruchirapalli 620020, Tamil Nadu (India); Chandra Shekar, N.V., E-mail: chandru@igcar.gov.in [Condensed Matter Physics Division, Materials Science Group, Indira Gandhi Centre for Atomic Research, Kalpakkam 603102, Tamil Nadu (India); Amirthapandian, S. [Materials Physics Division, Materials Science Group, Indira Gandhi Centre for Atomic Research, Kalpakkam 603102, Tamil Nadu (India); Hussain, Shamima [UGC-DAE-CSR node, Kokilamedu 603103, Tamil Nadu (India); Arulraj, A.; Sahu, P. Ch. [Condensed Matter Physics Division, Materials Science Group, Indira Gandhi Centre for Atomic Research, Kalpakkam 603102, Tamil Nadu (India)

    2014-09-15

    The phase stability of nanocrystalline Pr{sub 2}O{sub 3} has been investigated under pressure by in-situ high pressure X-ray diffraction using Mao-Bell type diamond anvil cell. The ambient structure and phase of the praseodymium oxide have been resolved unambiguously using x-ray diffraction, SEM and TEM techniques. Under the action of pressure the cubic phase of the system is retained up to 15 GPa. This is unusual as other isostructural rare earth oxides show structural transformations even at lower pressures. From the best fit to the P–V data with the Murnaghan equation of state yields a bulk modulus of 171 GPa.

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

    International Nuclear Information System (INIS)

    Kumar, Munish

    1998-01-01

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

  9. Bench-Scale Development of a Hot Carbonate Absorption Process with Crystallization-Enabled High Pressure Stripping for Post-Combustion CO{sub 2} Capture

    Energy Technology Data Exchange (ETDEWEB)

    Lu, Yongqi

    2014-02-01

    This report summarizes the methodology and preliminary results of a techno-economic analysis on a hot carbonate absorption process (Hot-CAP) with crystallization-enabled high pressure stripping for post-combustion CO{sub 2} capture (PCC). This analysis was based on the Hot-CAP that is fully integrated with a sub-critical steam cycle, pulverized coal-fired power plant adopted in Case 10 of the DOE/NETL’s Cost and Performance Baseline for Fossil Energy Plants. The techno-economic analysis addressed several important aspects of the Hot-CAP for PCC application, including process design and simulation, equipment sizing, technical risk and mitigation strategy, performance evaluation, and cost analysis. Results show that the net power produced in the subcritical power plant equipped with Hot-CAP is 611 MWe, greater than that with Econoamine (550 MWe). The total capital cost for the Hot-CAP, including CO{sub 2} compression, is $399 million, less than that for the Econoamine PCC ($493 million). O&M costs for the power plant with Hot-CAP is $175 million annually, less than that with Econoamine ($178 million). The 20-year levelized cost of electricity (LCOE) for the power plant with Hot-CAP, including CO2 transportation and storage, is 119.4 mills/kWh, a 59% increase over that for the plant without CO2 capture. The LCOE increase caused by CO{sub 2} capture for the Hot-CAP is 31% lower than that for its Econoamine counterpart.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2013-01-28

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

  11. 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.

  12. Thermally induced coloration of KBr at high pressures

    Science.gov (United States)

    Arveson, Sarah M.; Kiefer, Boris; Deng, Jie; Liu, Zhenxian; Lee, Kanani K. M.

    2018-03-01

    Laser-heated diamond-anvil cell (LHDAC) experiments reveal electronic changes in KBr at pressures between ˜13 -81 GPa when heated to high temperatures that cause runaway heating to temperatures in excess of ˜5000 K . The drastic changes in absorption behavior of KBr are interpreted as rapid formation of high-pressure F-center defects. The defects are localized to the heated region and thus do not change the long-range crystalline order of KBr. The results have significant consequences for temperature measurements in LHDAC experiments and extend the persistence of F centers in alkali halides to at least 81 GPa.

  13. 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.)

  14. Infrared spectra of hexamethylbenzene—tetracyanoethylene complexes at high pressures

    Science.gov (United States)

    Yamada, Haruka; Saheki, Masao

    Infrared spectra of hexamethylbenzene(HMB)—tetracyanoethylene(TCNE), 1:1 and 2:1, complexes were measured under high pressures, 11˜4,000 bar. It was found that the CC stretching (A g) band of TCNE became much stronger at high pressures than at 1 bar and that the intensity increase of this band was especially large for both of the complexes. Based on these facts the strong appearance of the CC band at 1 bar, which is inconsistent with the symmetry consideration derived from X-ray analysis, can be discussed.

  15. High-pressure cell for simultaneous dielectric and neutron spectroscopy

    DEFF Research Database (Denmark)

    Sanz, Alejandro; Hansen, Henriette Wase; Jakobsen, Bo

    2018-01-01

    In this article, we report on the design, manufacture, and testing of a high-pressure cell for simultaneous dielectric and neutron spectroscopy. This cell is a unique tool for studying dynamics on different time scales, from kilo- to picoseconds, covering universal features such as the α relaxation......, a cylindrical capacitor is positioned within the bore of the high-pressure container. The capacitor consists of two concentric electrodes separated by insulating spacers. The performance of this setup has been successfully verified by collecting simultaneous dielectric and neutron spectroscopy data...

  16. 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

  17. Desirability of oysters treated by high pressure processing at different temperatures and elevated pressures

    Science.gov (United States)

    Organoleptic changes in sterile triploid oysters (Crassostrea virginica) induced by high pressure processing (HPP) were investigated using a volunteer panel. Using a 1-7 hedonic scale, where seven is “like very much”, and one is “dislike very much”, oysters were evaluated organoleptically for flavo...

  18. Nuclear data requirements for accelerator driven sub-critical systems

    Indian Academy of Sciences (India)

    The development of accelerator driven sub-critical systems (ADSS) require significant amount of new nuclear data in extended energy regions as well as for a variety of new materials. This paper reviews these perspectives in the Indian context.

  19. 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.

  20. High Pressure Angle Gears: Comparison to Typical Gear Designs

    Science.gov (United States)

    Handschuh, Robert F.; Zabrajsek, Andrew J.

    2010-01-01

    A preliminary study has been completed to determine the feasibility of using high-pressure angle gears in aeronautic and space applications. Tests were conducted in the NASA Glenn Research Center (GRC) Spur Gear Test Facility at speeds up to 10,000 rpm and 73 N*m (648 in.*lb) for 3.18, 2.12, and 1.59 module gears (8, 12, and 16 diametral pitch gears), all designed to operate in the same test facility. The 3.18 module (8-diametral pitch), 28 tooth, 20deg pressure angle gears are the GRC baseline test specimen. Also, 2.12 module (12-diametral pitch), 42 tooth, 25deg pressure angle gears were tested. Finally 1.59 module (16-diametral pitch), 56 tooth, 35deg pressure angle gears were tested. The high-pressure angle gears were the most efficient when operated in the high-speed aerospace mode (10,000 rpm, lubricated with a synthetic turbine engine oil), and produced the lowest wear rates when tested with a perfluoroether-based grease. The grease tests were conducted at 150 rpm and 71 N*m (630 in.*lb).