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Sample records for hydrostatic depoling characteristics

  1. WORK PRINCIPLE AND CHARACTERISTIC ANALYSES OF HYDROSTATIC BEARING

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Aiming at the new characteristic of water hydraulic system, a kind of hydrostatic bearing with a concentric gap damper is introduced. The lubricative film thickness of the hydrostatic bearing possesses inflexibility and the loading capacity is just determined by the geometrical dimension of the piston-slipper subassembly and has no relation with system pressure, viscosity and temperature of water and speed of rotor. Theoretical analyses and the verification of scheme done at the test rig show that the hydrostatic bearing with a concentric gap damper is especially fit for water hydraulic components.

  2. Influence of Floating Monitoring Platform Structure on the Hydrostatic Characteristics

    Directory of Open Access Journals (Sweden)

    Su Feng

    2015-01-01

    Full Text Available According to the environment and work styles, the underwater monitoring devices can be divided into three type, fixed monitoring device, the floating monitoring device and mobile monitoring device. Floating monitoring platform is a new type of monitoring device of the floating monitoring device, which is mainly used for underwater video monitoring of pool. as the floating platform monitoring in water motion and hydrostatic characteristics are closely related, the influent of counterweight, weight distance and floating body diameter of the structure parameters on its hydrostatic characteristics and the natural periods for roll, pitch and heave should be considered, In this work, the floating body diameter influent most, the counterweight followed, and the structure parameters have different influence on the natural periods for roll, pitch and heave , it need to be analyzed according to the concrete structure parameters.

  3. Simulation and experimental analysis of supporting characteristics of multiple oil pad hydrostatic bearing disk

    Institute of Scientific and Technical Information of China (English)

    ZHANG Yan-qin; FAN Li-guo; LI Rui; DAI Chun-xi; YU Xiao-dong

    2013-01-01

    To study the heavy hydrostatic bearing with multiple oil pads,a reasonably simplified model of the pad is put forward,and the mathematical model of the bearing characteristics of the multiple oil pad hydrostatic bearing is built with consideration of variable viscosity.The pressure field in the clearance oil film of the hydrostatic bearing at various velocities is simulated based on the Finite Volume Method (FVM) by using the software of Computational Fluid Dynamics (CFD).Some pressure experiments on the hydrostatic bearing were carried out and the results verified the rationality of the simplified model of the pad and the validity of the numerical simulation.It is concluded that the viscosity has a great influence on the pressure in the heavy hydrostatic beating and cannot be neglected,especially,in cases of high rotating speed.The results of numerical calculations provide the internal flow states inside the bearing,which would help the design of the oil cavity structure of the bearing in engineering practice.

  4. Thermal and tilt effects on bearing characteristics of hydrostatic oil pad in rotary table

    Institute of Scientific and Technical Information of China (English)

    刘志峰; 湛承鹏; 程强; 赵永胜; 李小燕; 王义达

    2016-01-01

    Hydrostatic pads are key components of a constant flow compensation hydrostatic rotary table. The tilt and thermal effects due to the partial load, the manufacturing errors and the friction must be considered. However, designers are more likely inclined to ignore these effects. In this work, the coupled characteristics of the tilt and thermal effects are studied. A coupled mathematical model to calculate the bearing properties of the pads is built. This model takes into consideration of tilt and thermal effects and is used to solve the flow problem by the finite difference method. The characteristics of the oil pad, including, the recess pressures, the load carrying capacity and the damping coefficients, are obtained and the tilt and thermal effects are analyzed. It is observed that the tilt has a tremendous impact on the bearing characteristics of the hydrostatic pad. The recess pressure, the load carrying capacity and the stiffness are reduced by 50% and the pressure distribution and the temperature distribution of the oil film also change significantly. When the pads work under a tilt operation, a larger land width is better for its bearing properties. It is also observed that the thermal effect is significant and cannot be ignored.

  5. Static characteristics design of hydrostatic guide-ways based on fluid-structure interactions

    Science.gov (United States)

    Lin, Shuo; Yin, YueHong

    2016-10-01

    With the raising requirements in micro optical systems, the available machines become hard to achieve the process dynamic and accuracy in all aspects. This makes compact design based on fluid/structure interactions (FSI) important. However, there is a difficulty in studying FSI with oil film as fluid domain. This paper aims at static characteristic design of a hydrostatic guide-way with capillary restrictors based on FSI. The pressure distribution of the oil film land is calculated by solving the Reynolds-equation with Galerkin technique. The deformation of structure is calculated by commercial FEM software, MSC. Nastran. A matlab program is designed to realize the coupling progress by modifying the load boundary in the submitting file and reading the deformation result. It's obvious that the stiffness of the hydrostatic bearing decreases with the weakening of the bearing structure. This program is proposed to make more precise prediction of bearing stiffness.

  6. Recrystallization characteristics of high hydrostatic pressure gelatinized normal and waxy corn starch.

    Science.gov (United States)

    Li, Wenhao; Tian, Xiaoling; Wang, Peng; Saleh, Ahmed S M; Luo, Qingui; Zheng, Jianmei; Ouyang, Shaohui; Zhang, Guoquan

    2016-02-01

    High hydrostatic pressure (HHP) can lead to starch gelatinization at room temperature, while the retrogradation mechanism of HHP gelatinized starch is not well known. HHP gelatinized normal and waxy corn starches were stored at room temperature for 192 h in order to investigate the retrogradation characteristics. The scanning electron microscopy (SEM), polarised light microscopy and differential scanning calorimetric (DSC) analysis showed that the pressurization of normal and waxy corn starch suspensions with concentration of 30% (w/v) at 600 MPa for 15 min resulted in a complete gelatinization. In addition, the pressure-gelatinized normal and waxy corn starch gels were stored and subjected to X-ray diffraction (XRD) analysis, resistant starch content determination, swelling power and pasting behavior. The retrograded normal maize and waxy maize starch showed a substantial loss of A-type crystallinity. Both pressure-gelatinized normal and waxy corn starches showed an increase in resistant starch content and relative crystallinity degree with the increase of storage time. In addition, restricted starch swelling power and lower pasting viscosities were observed for these two retrograded starches. The amylose molecule within starch granules has been regarded as the main factor to affect the structural and physicochemical properties during the retrogradation process of HHP-gelatinized starch granules.

  7. Effect of high hydrostatic pressure, ultrasound and pulsed electric fields on milk composition and characteristics

    Directory of Open Access Journals (Sweden)

    Irena Jeličić

    2012-03-01

    Full Text Available High hydrostatic pressure, ultrasonication and pulsed eletrcic fields (PEF belong to novel food processing methods which are mostly implemented in combination with moderate temperatures and/ or in combination with each other in order to provide adequate microbiological quality with minimal losses of nutritional value. All of three mentioned methods have been intensively investigated for the purpose of inactivation and reduction of foodborne microorganisms present in milk and dairy products. However, a large number of scientific researches have been dedicated to investigation of impact of these methods on changes in constituents like milk fat, milk proteins and lactose as well as changes in mechanisms like renneting properties and coagulation of milk. The aim of this research was to give an overview of changes in milk constituents induced by high hydrostatic pressure, ultrasonification and pulsed electric field treatments as well as to suggest how these changes could improve conventional processes in the dairy industry.

  8. Effects of Dopant on Depoling Temperature in Modified BiScO3 - PbTiO3

    Science.gov (United States)

    Kowalski, Benjamin; Sehirlioglu, Alp

    2014-01-01

    In recent years there has been a renewed interest for high temperature piezoelectrics for both terrestrial and aerospace applications. These applications are limited in part by the operating temperature, which is usually taken as one half of the Curie temperature (Tc), and is 200C for one of the most widely used commercial piezoelectrics, Pb(Zr,Ti)O3 (PZT). In an effort to increase Tc, subsequent research into high temperature Bi(BB)O3 PbTiO3 piezoelectrics led to the discovery of the morphotropic phase boundary (MPB) in the high-Tc BiScO3 PbTiO3 (BS-PT) system with a Tc of 460C and a d33 of 460 pmV. The Tc marks the ferroelectric to paraelectric phase transformation and while, in general, a phase transformation leads to thermal depoling in piezoelectrics with low or moderate Tcs, for high Tc piezoelectrics thermally assisted dipole rotation can lead to randomization of domains at temperatures below Tc. It becomes necessary to determine the depoling temperature (Td) which dictates the actual working temperature range. By doping for Sc and Ti the Td can be shifted while maintaining similar electromechanical properties as a function of temperature. The effect of this B-site doping on depoling temperature has been explored through the characterization of microstructure and weakhigh field measurements.

  9. Physicochemical characteristics and quality parameters of a beef product subjected to chemical preservatives and high hydrostatic pressure.

    Science.gov (United States)

    Giménez, Belén; Graiver, Natalia; Califano, Alicia; Zaritzky, Noemí

    2015-02-01

    The use of high hydrostatic pressure (HHP) on fresh beef causes a deleterious effect on red colour. A beef product subjected to HHP exhibiting acceptable colour and microbiological stability was developed; the process requires as a first step the immersion in a preservative solution containing ascorbic acid, sodium nitrite, and sodium chloride. Desirability functions were used to optimise the composition of this solution in order to maintain the colour attributes minimising the concentration of sodium nitrite. The product was packed in low gas permeability film before HHP treatment. The effect of the applied pressure (300, 600 MPa) on quality parameters (colour,texture) was analysed. The stability of the product during storage at 4 °C was determined by microbial counts, colour, texture, and exudate. The combination of treatments provided acceptable colour and microbiological stability during four and six weeks of refrigerated storage after the product has been subjected to 300 and 600 MPa, respectively.

  10. The Effect of Shock Stress and Field Strength on Shock-Induced Depoling of Normally Poled PZT 95/5

    Energy Technology Data Exchange (ETDEWEB)

    CHHABILDAS,LALIT C.; FURNISH,MICHAEL D.; MONTGOMERY,STEPHEN T.; SETCHELL,ROBERT E.

    1999-09-01

    Shock-induced depoling of the ferroelectric ceramic PZT 95/5 is utilized in a number of pulsed power devices. Several experimental and theoretical efforts are in progress in order to improve numerical simulations of these devices. In this study we have examined the shock response of normally poled PZT 95/5 under uniaxial strain conditions. On each experiment the current produced in an external circuit and the transmitted waveform at a window interface were recorded. The peak electrical field generated within the PZT sample was varied through the choice of external circuit resistance. Shock pressures were varied from 0.6 to 4.6 GPa, and peak electrical fields were varied from 0.2 to 37 kV/cm. For a 2.4 GPa shock and the lowest peak field, a nearly constant current governed simply by the remanent polarization and the shock velocity was recorded. Both decreasing the shock pressure and increasing the electrical field resulted in reduced current generation, indicating a retardation of the depoling kinetics.

  11. Effect of high hydrostatic pressure on seed germination, microbial quality, anatomy-morphology and physiological characteristics of garden cress (Lepidium sativum) seedlings

    Science.gov (United States)

    İşlek, Cemil; Murat Altuner, Ergin; Çeter, Talip; Alpas, Hami

    2013-06-01

    High hydrostatic pressure is a non-thermal food processing technology that is found to increase the percentage of germination, decrease the germination time and improve the microbial quality of seeds. In this study, pressures of 100-400 MPa for 10 min at 30°C are used to compare the percentage of germination, the microbial quality of seeds, chlorophyll a and b, and total phenolic compounds concentrations in seedlings, and the anatomy-morphology characteristics of garden cress. Enhanced reductions of total aerobic mesophilic bacteria, total and fecal coliforms, and yeast and mould populations in seeds were observed, especially at 300 MPa. In addition, the percentage of germination, chlorophyll content and phenolic compounds concentrations, fresh and dry weights, and hypocotyl lengths of the seedlings are higher than those of all samples, where the percentage of germination is equal to controls but higher than other samples, and radicula length is lower than controls but higher than others.

  12. Oenological characteristics, amino acids and volatile profiles of Hongqu rice wines during pottery storage: Effects of high hydrostatic pressure processing.

    Science.gov (United States)

    Tian, Yuting; Huang, Jiamei; Xie, Tingting; Huang, Luqiang; Zhuang, Weijin; Zheng, Yafeng; Zheng, Baodong

    2016-07-15

    Hongqu rice wines were subjected to high hydrostatic pressure (HHP) treatments of 200 MPa and 550 MPa at 25 °C for 30 min and effects on wine quality during pottery storage were examined. HHP treatment can significantly (pwines. After 18 months of storage, the HHP-treated wines exhibited a more rapid decrease in total sugars (9.3-15.3%), lower free amino acid content (e.g. lysine content decreased by 45.0-84.5%), and higher ketone content (e.g. 6- and 14-fold increase for 2-nonanone). These changes could be attributed to the occurrence of Maillard and oxidation reactions. The wines treated at 550 MPa for 30 min developed about twice as rapidly during pottery storage than untreated wines based on principal component analysis. After only 6 months, treated wines had a volatile composition and an organoleptic quality similar to that of untreated wines stored in pottery for 18 months. Copyright © 2016 Elsevier Ltd. All rights reserved.

  13. Inactivation of Vibrio parahaemolyticus in hard clams (Mercanaria mercanaria) by high hydrostatic pressure (HHP) and the effect of HHP on the physical characteristics of hard clam meat.

    Science.gov (United States)

    Mootian, Gabriel K; Flimlin, George E; Karwe, Mukund V; Schaffner, Donald W

    2013-02-01

    Shellfish may internalize dangerous pathogens during filter feeding. Traditional methods of depuration have been found ineffective against certain pathogens. The objective was to explore high hydrostatic pressure (HHP) as an alternative to the traditional depuration process. The effect of HHP on the survival of Vibrio parahaemolyticus in live clams (Mercanaria mercanaria) and the impact of HHP on physical characteristics of clam meat were investigated. Clams were inoculated with up to 7 log CFU/g of a cocktail of V. parahaemolyticus strains via filter feeding. Clams were processed at pressures ranging from 250 to 552 MPa for hold times ranging between 2 and 6 min. Processing conditions of 450 MPa for 4 min and 350 MPa for 6 min reduced the initial concentration of V. parahaemolyticus to a nondetectable level (5 log reductions. The volume of clam meat (processed in shell) increased with negligible change in mass after exposure to pressure at 552 MPa for 3 min, while the drip loss was reduced. Clams processed at 552 MPa were softer compared to those processed at 276 MPa. However, all HHP processed clams were found to be harder compared to unprocessed. The lightness (L*) of the meat increased although the redness (a*) decreased with increasing pressure. Although high pressure-processed clams may pose a significantly lower risk from V. parahaemolyticus, the effect of the accompanied physical changes on the consumer's decision to purchase HHP clams remains to be determined. Shellfish may contain dangerous foodborne pathogens. Traditional methods of removing those pathogen have been found ineffective against certain pathogens. The objective of this research was to determine the effect of high hydrostatic pressure on V. parahaemolyticus in clams. Processing conditions of 450 MPa for 4 min and 350 MPa for 6 min reduced the initial concentration of V. parahaemolyticus to a nondetectable level, achieving >5 log reductions. © 2013 Institute of Food Technologists®

  14. Effects of hydrostatic pressure/heat combinations on water uptake and gelatinization characteristics of japonica rice grains: a kinetic study.

    Science.gov (United States)

    Huang, Shih-Li; Jao, Chia-Ling; Hsu, Kuo-Chiang

    2009-10-01

    The combination effects of pressure (200 to 500 MPa) and temperature (20, 40, and 50 degrees C) on the water uptake and gelatinization characteristics of japonica rice (Tainung 71) grains were investigated. Pressure greater than 200 MPa at all temperatures increased the moisture content and volume of rice grains; meanwhile, the increase content of rice grain volume showed a high correlation with that of moisture content (r(2)= 0.96). The highest degree of gelatinization of 73% was observed at 500 MPa and 50 degrees C for 120 min, while gelatinization did not occur at pressures below 300 MPa and temperatures of 20 and 40 degrees C. The rate of gelatinization followed the 1st-order kinetics at each temperature and pressure. The higher pressures and temperatures would result in higher values of rate constant k which could be correlated with both pressure and temperature by combining Arrhenius and Eyring models.

  15. Annular Pressure Seals and Hydrostatic Bearings

    Science.gov (United States)

    2006-11-01

    affecting the rotordynamics of liquid turbopumps, in particular those handling large density fluids. Highlights on the bulk-flow analysis of annular seals... rotordynamic stability. Hydrostatic bearings rely on external fluid pressurization to generate load support and large centering stiffnesses, even in...SEALS IN PUMP APPLICATIONS Seal rotordynamic characteristic have a primary influence on the stability response of high-performance turbomachinery [1

  16. A Hydrostatic Paradox Revisited

    Science.gov (United States)

    Ganci, Salvatore

    2012-01-01

    This paper revisits a well-known hydrostatic paradox, observed when turning upside down a glass partially filled with water and covered with a sheet of light material. The phenomenon is studied in its most general form by including the mass of the cover. A historical survey of this experiment shows that a common misunderstanding of the phenomenon…

  17. A Hydrostatic Paradox Revisited

    Science.gov (United States)

    Ganci, Salvatore

    2012-01-01

    This paper revisits a well-known hydrostatic paradox, observed when turning upside down a glass partially filled with water and covered with a sheet of light material. The phenomenon is studied in its most general form by including the mass of the cover. A historical survey of this experiment shows that a common misunderstanding of the phenomenon…

  18. Role of twins in variations in the conductivity characteristics of single-crystal HoBa2Cu3O7-δ during reversible changes in hydrostatic pressure

    Science.gov (United States)

    Khadzhai, G. Ya.; Nazyrov, Z. F.; Vovk, R. V.

    2016-09-01

    The in-plane electrical resistivity of single-crystal HoBa2Cu3O7-δ (Tc = 62-66 K) is studied at temperatures Tc-300 K under conditions such that the measurement current flows parallel to twins or at an angle of 45° to them during reversible changes in hydrostatic pressure. The variations in Tc, in the parameters of the Bloch-Grueneisen equations, and in the parameters of the Aslamasov-Larkin model for fluctuation conductivity are analyzed. Application of a pressure facilitates the formation of a second phase with lower Tc that shows up more clearly when the measurement current flows across the twinning plane. In this case, the transverse coherence length and the interval within which the fluctuation conductivity exists are smaller than in the first configuration. The relaxation of the parameters characterizing the scatting of charge carriers on phonons and defects is related to the redistribution of oxygen between the two phases.

  19. 超高压技术结合气调包装保持冷藏带鱼品质%High hydrostatic pressure treatment combined with modified atmosphere package keeping quality characteristic ofTrichiurus lepturus during cold storage

    Institute of Scientific and Technical Information of China (English)

    谢晶; 杨茜; 张新林; 刘爱芳; 董韩博

    2015-01-01

    为探讨超高压结合气调包装对4℃冷藏带鱼品质的影响,该试验以超高压(290 MPa,6 min)前处理后4℃真空冷藏为对照,超高压(290 MPa,6 min)分别结合不同比例的气调包装体积分数为(60%CO2+40%N2、60%CO2+7%O2+33%N2、60%CO2+15%O2+25%N2、50%CO2+15%O2+35%N2)处理鲜带鱼并放置4℃冷藏。贮藏期间,以冷藏带鱼的感官评定(sensory evaluation,SE)、菌落总数(total plant count,TPC)、挥发性盐基氮(total volatile basic nitrogen, TVB-N)、硫代巴比妥酸(thiobarbituric acid,TBA)、肌动球蛋白溶出量(actomyosin content,AM)、肌动球蛋白的总巯基含量(total sulfhydryls content,TSH)为测定指标,研究不同气调包装对冷藏带鱼的保鲜效果。结果表明:通过菌落总数与TVB-N综合判定货架期可知,超高压处理鲜带鱼后真空贮藏仅延长冷藏带鱼货架期至11 d,超高压处理后气调贮藏各组:60%CO2+40%N2气调包装组可延长货架期至16d,60%CO2+7%O2+33%N2气调包装组可延长货架期至19d,60%CO2+15%O2+25%N2与50%CO2+15%O2+35%N2气调包装组可延长货架期至21d,是对照组货架期近2倍,说明超高压结合气调包装能有效抑制细菌总数增长和TVB-N产生。气调包装会加速超高压后带鱼肌动球蛋白和肌动球蛋白中总巯基含量的降低,且气调贮藏中高比例的O2对超高压处理后冷藏带鱼的脂肪氧化也有明显促进作用。因此综合考虑,超高压处理后结合60%CO2+7%O2+33%N2的气调包装在显著延长货架期的同时,仍可较好地保持冷藏带鱼原有鲜度。研究结果为冷藏带鱼的保鲜研究提供一定的理论参考。%s:The purpose of this paper was to study the effects of combined application of high hydrostatic pressure treatment and modified atmosphere packaging on the quality characteristics ofTrichiurus lepturus during cold storage at 4℃. The

  20. Hydrostatic extrusion of magnesium alloys

    NARCIS (Netherlands)

    Sillekens, W.H.; Bohlen, J.

    2012-01-01

    This chapter deals with the capabilities and limitations of the hydrostatic extrusion process for the manufacturing of magnesium alloy sections. Firstly, the process basics for the hydrostatic extrusion of materials in general and of magnesium in particular are introduced. Next, some recent research

  1. Static and dynamic characteristics of a hydrostatic guideway system based on electrorheological fluid%电流变液静压导轨系统静动态特性研究

    Institute of Scientific and Technical Information of China (English)

    胡均平; 刘成沛; 郭勇; 梁向京

    2016-01-01

    研究了一种以电流变液为润滑介质的静压导轨系统静动态特性。利用液阻网络理论,在分析电场强度与电流变液黏性关系,综合考虑关联参数的基础上,建立了电流变液静压导轨系统的 CFD 计算数值模型。根据摄动理论,利用 Fluent 动网格技术,研究了在不同工作变量下电流变液静压导轨的静动态特性。研究结果表明:电场强度、负载因素与初始压力比等工作变量均会对电流变液静压导轨系统性能带来影响;电场强度增强会使系统流量减小,阻尼系数增大,但不会对系统静刚度带来影响;改变切削力载荷频率,导轨系统会出现共振现象,增强电场强度可显著提高系统动刚度,抑制共振时的最大振幅。实验结果与仿真数值一致,为电流变液静压导轨的设计应用提供了理论参考依据。%The static and dynamic characteristics of a hydrostatic guideway system based on the lubricating medium of electrorheological fluid were studied.A numerical model for fluid dynamics computation was established according to the hydraulic resistance network theory and in comprehensive consideration of correlated parameters and the influence of electric field intensity on the characteristics of electrorheological fluid.The static and dynamic characteristics of the hydrostatic guideway based on the electrorheological fluid with different working variables were studied by using the fluent dynamic mesh technology and the perturbation theory.The results show that the static and dynamic characteristics of the hydrostatic guideway system can be influenced by the electric filed intensity,load factor and initial pressure ratio.The system flow rate will decrease and the damping coefficient will increase with the system stiffness remaining unchanged, when the electric filed intensity is enhanced under the condition of unchanged initially designed parameters and load factors.The resonance

  2. Non-hydrostatic versus hydrostatic modelings of free surface flows

    Institute of Scientific and Technical Information of China (English)

    ZHANG Jing-xin; SUKHODOLOV Alexander N.; LIU Hua

    2014-01-01

    The hydrodynamics of geophysical flows in oceanic shelves, estuaries, and rivers are often studied by solving shallow water equations under either hydrostatic or non-hydrostatic assumptions. Although the hydrostatic models are quite accurate and cost-efficient for many practical applications, there are situations when the fully hydrodynamic models are preferred despite a larger cost for computations. The present numerical model is implemented by the finite volume method (FVM) based on unstructured grids. The model can be efficiently switched between hydrostatic and non-hydrostatic modules. The case study shows that for waves pro- pagating along the bar a criterion with respect to the shallowness alone, the ratio between the depth and the wave length, is insu- fficient to warrant the performance of shallow flow equations with a hydrostatic approach and the nonlinearity in wave dynamics can be better accounted with a hydrodynamic approach. Besides the prediction of the flows over complex bathymetries, for instance, over asymmetrical dunes, by a hydrodynamic approach is shown to be superior in accuracy to the hydrostatic simulation.

  3. Slurry pipeline hydrostatic testing

    Energy Technology Data Exchange (ETDEWEB)

    Betinol, Roy G.; Navarro Rojas, Luis Alejandro [BRASS Chile S.A., Santiago (Chile)

    2009-07-01

    The transportation of concentrates and tailings through long distance pipeline has been proven in recent years to be the most economic, environmentally friendly and secure means of transporting of mine products. This success has led to an increase in the demand for long distance pipeline throughout the mining industry. In year 2007 alone, a total of over 500 km of pipeline has been installed in South America alone and over 800 km are in the planning stages. As more pipelines are being installed, the need to ensure its operating integrity is ever increasing. Hydrostatic testing of long distance pipeline is one of the most economical and expeditious way to proving the operational integrity of the pipe. The intent of this paper is to show the sound reasoning behind construction hydro testing and the economic benefit it presents. It will show how hydro test pressures are determined based on ASME B31.11 criteria. (author)

  4. Hydraulic energy storage for hydrostatic travel drives; Hydraulischer Energiespeicher fuer hydrostatische Fahrantriebe

    Energy Technology Data Exchange (ETDEWEB)

    Renz, Klaus [Bosch Rexroth AG, Elchingen (Germany). Anwendungstechnik Strassenbaumaschinen und Raupenfahrzeuge; Vogl, Karl-Heinz [Bosch Rexroth AG, Elchingen (Germany). Anwendungstechnik, Technischer Vertrieb; Brand, Michael [Bosch Rexroth AG, Elchingen (Germany). Anwendungsentwicklung Arbeitsmaschinen

    2010-09-15

    with their Hydraulic Fly Wheel (HFW) Bosch Rexroth has developed a new concept for hydrostatic travel drives which addresses the changed characteristics of the newest engine generation. As a consequence of the Tier 4 final regulations engines will soon exhibit more sluggish load assumption behaviour - the hydraulic fly wheel compensates for this and assists the hydrostatic travel drive or implement hydraulics. (orig.)

  5. Hydrostatic and hybrid bearing design

    CERN Document Server

    Rowe, W B

    1983-01-01

    Hydrostatic and Hybrid Bearing Design is a 15-chapter book that focuses on the bearing design and testing. This book first describes the application of hydrostatic bearings, as well as the device pressure, flow, force, power, and temperature. Subsequent chapters discuss the load and flow rate of thrust pads; circuit design, flow control, load, and stiffness; and the basis of the design procedures and selection of tolerances. The specific types of bearings, their design, dynamics, and experimental methods and testing are also shown. This book will be very valuable to students of engineering des

  6. Scientific Evidence for Hydrostatic Shock

    CERN Document Server

    Courtney, Michael

    2008-01-01

    This paper reviews the scientific support for a ballistic pressure wave radiating outward from a penetrating projectile and causing injury and incapacitation. This phenomenon is known colloquially as "hydrostatic shock." The idea apparently originates with Col. Frank Chamberlin, a World War II trauma surgeon and wound ballistics researcher. The paper reviews claims that hydrostatic shock is a myth and considers supporting evidence through parallels with blast, describing the physics of the pressure wave, evidence for remote cerebral effects, and remote effects in the spine and other internal organs. Finally, the review considers the levels of energy transfer required for the phenomenon to be readily observed.

  7. Pellissier H5 hydrostatic level

    CERN Document Server

    Imfeld, H L

    2003-01-01

    Conventional spirit leveling using double scale invar rods has been in use at SLAC for some time as the standard method of obtaining very precise height difference information. Typical accuracy of +- 100 (micro)m and better can routinely be achieved. Procedures and software have evolved to the point where the method is relatively fast and reliable. However, recent projects such as the Final Focus Test Beam have pushed the requested vertical positioning tolerances for alignment of quadrupoles to the 30 mu m level. It is apparent that conventional spirit leveling cannot achieve this level of accuracy. To meet the challenge, the alignment group contracted with Pellissier, Inc. to develop a portable hydrostatic leveling system. The H5 grew out of this development effort and is expected to provide the needed accuracy and ease of use required for such vertical positioning projects. The H5 hydrostatic level is a portable instrument that under ideal operating conditions will provide elevation differences with an accu...

  8. Food processing by high hydrostatic pressure.

    Science.gov (United States)

    Yamamoto, Kazutaka

    2017-04-01

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

  9. Fluid Compressibility Effects on the Dynamic Response of Hydrostatic Journal Bearings

    Science.gov (United States)

    Sanandres, Luis A.

    1991-01-01

    A theoretical analysis for the dynamic performance characteristics of laminar flow, capillar/orifice compensated hydrostatic journal bearings is presented. The analysis considers in detail the effect of fluid compressibility in the bearing recesses. At high frequency excitations beyond a break frequency, the bearing hydrostatic stiffness increases sharply and it is accompanied by a rapid decrease in direct damping. Also, the potential of pneumatic hammer instability (negative damping) at low frequencies is likely to occur in hydrostatic bearing applications handling highly compressible fluids. Useful design criteria to avoid undesirable dynamic operating conditions at low and high frequencies are determined. The effect of fluid recess compressibility is brought into perspective, and found to be of utmost importance on the entire frequency spectrum response and stability characteristics of hydrostatic/hybrid journal bearings.

  10. Effect of High Hydrostatic Pressure Treatment on Enzymolysis Characteristics of Thermo-Denatured Rice Protein%高压处理对热变性米蛋白酶解特性的影响

    Institute of Scientific and Technical Information of China (English)

    王章存; 田卫环; 赵学伟; 郑坚强; 李昌文; 崔胜文

    2012-01-01

    Some enzymolysis properties such as solubility, hydrolysis degree, — SH content, molecular characteristics and microcosmic morphology of high hydrostatic pressure (HHP) treated thermal denatured rice protein during hydrolysis with alcalase were investigated. The results showed that the contents of soluble rice protein and free —SH in samples pretreated at high pressure 100-700 MPa were both increased (especially at 500 MPa), compared with that of untreated samples. The ratio of soluble rice protein in the hydrolysate obtained after HHP treatment at 500 MPa followed by 120 min of hydrolysis was 73. 0% compared with only 53.6% for that obtained for non-HHP treated rice protein. However, no obvious difference in the degree of hydrolysis was found. The gel filtration chromatographic analysis indicated that soluble hydrolysates with lower relative molecular mass were obtained using HHP treatment and subsequent enzymatic hydrolysis compared to direct enzymatic hydrolysis. The SDS-PAGE analysis indicated that the content of high-molecular-mass components in insoluble hydrolysates of HHP treated rice protein decreased notably, while that of low-molecular-mass components increased distinctly. As observed under a scanning electron microscope (SEM), the morphology of HHP treated rice protein was relatively loose. Therefore, the appropriate HHP treatment was beneficial to the hydrolysis of rice protein and enzymatic hydrolysis characteristics were directly associated with structural changes in rice protein caused by HHP treatment.%研究高压处理热变性米蛋白俚碱性蛋白酶酶解时其溶解性、水解度、—SH含量、分子特征和微观形态的变化特征。结果显示:米蛋白经100-700MPa处理后酶解所得可溶性蛋白的含量均高于未高压处理者,其中500MPa时增加幅度最大,一SH含量也最高。当酶解120min时,高压处理米蛋白可溶性米蛋白的比例达73.0%,而未高压处理米蛋

  11. Friction phenomena in hydrostatic extrusion of magnesium

    NARCIS (Netherlands)

    Moodij, Ellen

    2014-01-01

    When magnesium is hydrostatically extruded an inconsistent and sometimes bad surface quality is encountered. In hydrostatic extrusion the billet is surrounded by a lubricant, usually castor oil. The required pressure to deform the material is applied onto this lubricant and not directly to the bill

  12. On hydrostatic flows in isentropic coordinates

    NARCIS (Netherlands)

    Bokhove, Onno

    2000-01-01

    The hydrostatic primitive equations of motion which have been used in large-scale weather prediction and climate modelling over the last few decades are analysed with variational methods in an isentropic Eulerian framework. The use of material isentropic coordinates for the Eulerian hydrostatic equa

  13. Physiological hydrostatic pressure protects endothelial monolayer integrity.

    Science.gov (United States)

    Müller-Marschhausen, K; Waschke, J; Drenckhahn, D

    2008-01-01

    Endothelial monolayer integrity is required to maintain endothelial barrier functions and has found to be impaired in several disorders like inflammatory edema, allergic shock, or artherosclerosis. Under physiologic conditions in vivo, endothelial cells are exposed to mechanical forces such as hydrostatic pressure, shear stress, and cyclic stretch. However, insight into the effects of hydrostatic pressure on endothelial cell biology is very limited at present. Therefore, in this study, we tested the hypothesis that physiological hydrostatic pressure protects endothelial monolayer integrity in vitro. We investigated the protective efficacy of hydrostatic pressure in microvascular myocardial endothelial (MyEnd) cells and macrovascular pulmonary artery endothelial cells (PAECs) by the application of selected pharmacological agents known to alter monolayer integrity in the absence or presence of hydrostatic pressure. In both endothelial cell lines, extracellular Ca(2+) depletion by EGTA was followed by a loss of vascular-endothelial cadherin (VE-caherin) immunostaining at cell junctions. However, hydrostatic pressure (15 cmH(2)O) blocked this effect of EGTA. Similarly, cytochalasin D-induced actin depolymerization and intercellular gap formation and cell detachment in response to the Ca(2+)/calmodulin antagonist trifluperazine (TFP) as well as thrombin-induced cell dissociation were also reduced by hydrostatic pressure. Moreover, hydrostatic pressure significantly reduced the loss of VE-cadherin-mediated adhesion in response to EGTA, cytochalasin D, and TFP in MyEnd cells as determined by laser tweezer trapping using VE-cadherin-coated microbeads. In caveolin-1-deficient MyEnd cells, which lack caveolae, hydrostatic pressure did not protect monolayer integrity compromised by EGTA, indicating that caveolae-dependent mechanisms are involved in hydrostatic pressure sensing and signaling.

  14. Archimedes and the Hydrostatic Balance

    Directory of Open Access Journals (Sweden)

    Nasser Meneghetti Lanza

    2016-02-01

    Full Text Available The objective of this report is to discuss how Archimedes would have solved the problem of Hieron king's crown, addressing the solution mentioned by Galileo, proposing a discussion on the subject and seeking a resolution not only watertight . It is also proposed to show an educational alternative, which is a practical activity carried out with students of the Polytechnic School and regular, looking for a conceptual and historical linkage of science. Describes the critical line of Galileo, translated quotes of authors, lists a series of opposition elements to the story told in textbooks and present a proposal for qualitative analysis with concept maps, in search subsumers and evaluation of results after application of an activity using the hydrostatic balance. .

  15. Hydrostatic Hyperbaric Chamber Ventilation System

    Science.gov (United States)

    Sarguisingh, Miriam J.

    2012-01-01

    The hydrostatic hyperbaric chamber (HHC) represents the merger of several technologies in development for NASA aerospace applications, harnessed to directly benefit global health. NASA has significant experience developing composite hyperbaric chambers for a variety of applications. NASA also has researched the application of water-filled vessels to increase tolerance of acceleration forces. The combination of these two applications has resulted in the hydrostatic chamber, which has been conceived as a safe, affordable means of making hyperbaric oxygen therapy (HBOT) available in the developing world for the treatment of a variety of medical conditions. Specifically, HBOT is highly-desired as a possibly curative treatment for Buruli Ulcer, an infectious condition that afflicts children in sub-Saharan Africa. HBOT is simply too expensive and too dangerous to implement in the developing world using standard equipment. The HHC technology changes the paradigm. The HHC differs from standard hyperbaric chambers in that the majority of its volume is filled with water which is pressurized by oxygen being supplied in the portion of the chamber containing the patient s head. This greatly reduces the amount of oxygen required to sustain a hyperbaric atmosphere, thereby making the system more safe and economical to operate. An effort was taken to develop an HHC system to apply HBOT to children that is simple and robust enough to support transport, assembly, maintenance and operation in developing countries. This paper details the concept for an HHC ventilation and pressurization system to provide controlled pressurization and adequate washout of carbon dioxide while the subject is enclosed in the confined space during the administration of the medical treatment. The concept took into consideration operational complexity, safety to the patient and operating personnel, and physiological considerations. The simple schematic, comprised of easily acquired commercial hardware

  16. Depoling and fatigue behavior of Pb(Mg1/3Nb2/3)O3-PbTiO3 single crystal at megahertz frequencies under bipolar electric field

    Science.gov (United States)

    Chen, Zhaojiang; Li, Shiyang; Zhang, Yang; Cao, Wenwu

    2017-05-01

    Bipolar electric field induced degradation in [001]c poled Pb(Mg1/3Nb2/3)O3-0.29PbTiO3 (PMN-0.29PT) single crystals was investigated at megahertz frequencies. The electromechanical coupling factor kt, dielectric constant ɛr, dielectric loss D, and piezoelectric constant d33 were measured as a function of amplitude, frequency, and number of cycles of the applied electric field. Our results showed that samples degrade rapidly when the field amplitude is larger than a critical value due to the onset of domain switching. We define this critical value as the effective coercive field Ec at high frequencies, which increases drastically with frequency. We also demonstrate an effective counter-depoling method by using a dc bias, which could help the design of high field driven devices based on PMN-PT single crystals and operated at megahertz frequencies.

  17. 基于PM流量控制器的开式液体静压导轨动态特性分析%Dynamic Characteristic Analysis of Open-type Hydrostatic Guide Based on PM Flow Controller

    Institute of Scientific and Technical Information of China (English)

    高殿荣; 张作超; 赵建华

    2012-01-01

    Hydrostatic guide system,which is actually nonlinear system,usually is considered as the linear system when the dynamic performance is concerned,however,the error via linearization transform has not been analyzed.Take the open-type hydrostatic guide adjusted by PM flow Controller as an example,the nonlinear differential equations of the pressure and flow are derived.One method to linearize the nonlinear differential equations by Laplace transform and the corresponding transfer functions are obtained,and the step response curves and the pulse response curves are presented in this paper.The other method for hydrostatic guide system is to use Simulink tool box to build the nonlinear system block diagram of the guide system.The corresponding step response curves and the pulse response curves are presented as well.Comparing the response curves from these two different methods,the difference between the results are very small,and the precision of these two methods can meet the demand of the practical engineering application,and the linear treatment is valid for the open-type hydrostatic slide adjusted by the PM controller.Based on these methods,the dynamic performance on the slide is analyzed,and the amplitude-frequency curves,the phase-frequency curves,and the dynamic stiffness-frequency curves are presented.The present study provides a theoretical basis for the open-type hydrostatic slide based on PM flow Controller,and shows feasibility for the practical engineering applications.%液体静压导轨系统实质是非线性系统,在分析其动态特性时通常被简化为线性系统,然而目前还未见关于对线性化导致的误差进行研究的文献.以PM控制器调节下的开式静压导轨为对象,推导了导轨关于压力、流量的非线性微分方程组.一方面,对导轨支承系统进行线性化处理,利用Laplace变换的方法获得了系统的传递函数,并绘制了系统的阶跃响应和脉冲响

  18. Muscular hydrostat mechanism for lip protrusion in speech

    Science.gov (United States)

    Murano, Emi Z.; Stone, Maureen; Honda, Kiyoshi

    2005-09-01

    The lip is an organ consisting mostly of muscle similar to the tongue. While the tongue is known as a muscular hydrostat, it is unclear whether the lip is also. In this paper the muscular hydrostat issue was explored from the anatomical and functional point of view using high-resolution static MRI (hr-MRI 0.125 mm/pixel) and tagged-cineMRI (t-MRI). A 3-D reconstruction of the lips and its muscles was obtained from hr-MRI during sustained vowels /i/ and /u/. The muscular geometry of the orbicularis oris, mentalis, and depressor labii inferior muscles were superimposed onto the principal strains that depicts compression and expansion of the internal tissue obtained from t-MRI. It is shown that (1) orbicularis oris muscle shape can predict both the borderline of glabrous and hairy skin and the manner in which the lips are protruded; (2) the lips volume is almost identical for both speech tasks; and (3) direction and intensity of compression of orbicularis oris and mentalis muscle bundles imply the role of these muscles in the protrusion appearance. These results indicate that the muscular architecture and volume preserving characteristics of the lips are consistent with a muscular hydrostat. [This work was supported by NIH (USA) and NiCT (Japan).

  19. Mechanical response of collagen molecule under hydrostatic compression

    Energy Technology Data Exchange (ETDEWEB)

    Saini, Karanvir, E-mail: karans@iitrpr.ac.in; Kumar, Navin

    2015-04-01

    Proteins like collagen are the basic building blocks of various body tissues (soft and hard). Collagen molecules find their presence in the skeletal system of the body where they bear mechanical loads from different directions, either individually or along with hydroxy-apatite crystals. Therefore, it is very important to understand the mechanical behavior of the collagen molecule which is subjected to multi-axial state of loading. The estimation of strains of collagen molecule along different directions resulting from the changes in hydrostatic pressure magnitude, can provide us new insights into its mechanical behavior. In the present work, full atomistic simulations have been used to study global (volumetric) as well as local (along different directions) mechanical properties of the hydrated collagen molecule which is subjected to different hydrostatic pressure magnitudes. To estimate the local mechanical properties, the strains of collagen molecule along its longitudinal and transverse directions have been acquired at different hydrostatic pressure magnitudes. In spite of non-homogeneous distribution of atoms within the collagen molecule, the calculated values of local mechanical properties have been found to carry the same order of magnitude along the longitudinal and transverse directions. It has been demonstrated that the values of global mechanical properties like compressibility, bulk modulus, etc. as well as local mechanical properties like linear compressibility, linear elastic modulus, etc. are functions of magnitudes of applied hydrostatic pressures. The mechanical characteristics of collagen molecule based on the atomistic model have also been compared with that of the continuum model in the present work. The comparison showed up orthotropic material behavior for the collagen molecule. The information on collagen molecule provided in the present study can be very helpful in designing the future bio-materials.

  20. Smart adaptronic hydrostatic guiding system for machine tool slides

    Science.gov (United States)

    Munzinger, C.; Weis, M.; Herder, S.

    2009-03-01

    Guiding systems figure amongst the central components in the flux of a machine tool. Their characteristics have a direct impact on machining accuracy. Hydrostatic guiding systems are preferably used when specific requirements are to be met with regards to accuracy, stiffness and damping. However, an active intervention in the guiding system of such conventional systems, i.e. to absorb geometrical guiding rail errors, has so far not been possible. Compared to modular, conventional systems, adaptronic systems offer considerable cost savings potentials thanks to their increased functional degree of integration [1].

  1. Sensor of hydrostatic pressure based on gallium antimonide microcrystals

    Directory of Open Access Journals (Sweden)

    Druzhinin A. A.

    2015-08-01

    Full Text Available Currently, silicon and germanium, the most common materials in the production of discrete semiconductor devices and integrated circuits, do not always meet all the requirements to the sensing elements of mechanical quantities sensors. Therefore, it is logical to research the properties of other semiconductor materials that could be used as sensing elements in such sensors. A3B5 semiconductor compounds seem promising for such purpose. Effect of hydrostatic pressure up to 5000 bar on the resistance of n-type antimonide gallium whiskers doped by Se or Te was studied. Coefficient of hydrostatic pressure for this crystals was determined, it equals Kh = (16,5—20,0•10–5 bar–1 at 20°N. Temperature dependence of resistance and coefficient Kh for this crystals in the temperature range ±60°N was studied. Design of the developed hydrostatic pressure sensor based on GaSb whiskers and its characteristics are presented. The possibility to decrease the temperature dependence of sensitive element resistance by mounting GaSb whiskers on the substrates fabricated from materials with different temperature coefficient of expansion was examined. It was shown that mounting of GaSb crystals on Cu substrate gives the optimal result, in this case the temperature coefficient decrease to 0,05%•°N–1, that leads to decrease of output temperature dependence. The main advantages of developed pressure sensor are: the simplified design in comparison with pressure sensors with strain gauges mounted on spring elements; the high sensitivity to pressure that is constant in the wide pressure range; the improvement of sensors metrological characteristics owing to hysteresis absence. The possible application fields of developed sensors are measuring of high and extremely high pressure, chemical and oil industries, measuring of pressure in oil bore-holes, investigation of explosive processes.

  2. Effect of hydrostatic stress on yield function and plastic constitutive relations

    Institute of Scientific and Technical Information of China (English)

    盖秉政

    2001-01-01

    A new yield function taking effect of hydrostatic stress into account is presented through establishing and solving the functional equation satisfied by the yield function, and its characteristic is simple in form and strong in generality. In order to reveal its availability, a comparison is made between the results obtained with it and the experimental results of grey cast iron has be done, both seem to be in good agreement. At the same time, taking the yield function obtained here as a potential function, a new associative plastic constitutive equation taking effect of hydrostatic stress into account is built, and the plastic volume change ratio of plastic deformation is given.

  3. Analysis and Application on the Optimum Restrictive Parameters of Open Hydrostatic Slideway

    Institute of Scientific and Technical Information of China (English)

    YangJianxi; MengXinzhai; QianJinwu

    2004-01-01

    Open hydrostatic slideway has many advantages, that is, high moving precision, low power in friction, non-crawling and long working life. Near constant clearances of hydrostatic slideway may be obtained in a wide load range by applying new type variable restrictors, new static characteristic formulas and optimum restrictive parameters. Hydrostatic slideway has two characters. One is that the scope of external load is very large. Generally, the largest load is 2 to 6 times the smallest, the other is that the algebraic equation is a horizontal S shape curve, showing that the relation between slideway clearance and external load is a three exponents formula. The curve of the numerical values of this kind of three exponents formula just is the working curve when the hydrostatic slideway is moving, if one section is selected as the slideway work curve randomly without any analysis, the slideway clearance will be changed acutely along with the variation of external load. Selecting the optimum restrictive parameters and the beeline through two inflexions of the curve or tangent of the curve as the range of workload can ensure the minimal change of sliding clearance. Simultaneously, the hydrostatic sliding way has high beeline moving precision.

  4. A Numerical Study of Non-hydrostatic Shallow Flows in Open Channels

    Science.gov (United States)

    Zerihun, Yebegaeshet T.

    2017-06-01

    The flow field of many practical open channel flow problems, e.g. flow over natural bed forms or hydraulic structures, is characterised by curved streamlines that result in a non-hydrostatic pressure distribution. The essential vertical details of such a flow field need to be accounted for, so as to be able to treat the complex transition between hydrostatic and non-hydrostatic flow regimes. Apparently, the shallow-water equations, which assume a mild longitudinal slope and negligible vertical acceleration, are inappropriate to analyse these types of problems. Besides, most of the current Boussinesq-type models do not consider the effects of turbulence. A novel approach, stemming from the vertical integration of the Reynolds-averaged Navier-Stokes equations, is applied herein to develop a non-hydrostatic model which includes terms accounting for the effective stresses arising from the turbulent characteristics of the flow. The feasibility of the proposed model is examined by simulating flow situations that involve non-hydrostatic pressure and/or nonuniform velocity distributions. The computational results for free-surface and bed pressure profiles exhibit good correlations with experimental data, demonstrating that the present model is capable of simulating the salient features of free-surface flows over sharply-curved overflow structures and rigid-bed dunes.

  5. 46 CFR 61.30-10 - Hydrostatic test.

    Science.gov (United States)

    2010-10-01

    ... INSPECTIONS Tests and Inspections of Fired Thermal Fluid Heaters § 61.30-10 Hydrostatic test. All new installations of thermal fluid heaters must be given a hydrostatic test of 11/2 times the maximum allowable... condition of the heater warrants such a test. Where hydrostatic tests are required, an inspection is made...

  6. Hydrodynamic modelling of hydrostatic magnesium extrusion

    NARCIS (Netherlands)

    Moodij, E.; Rooij, de M.B.; Schipper, D.J.

    2006-01-01

    Wilson’s hydrodynamic model of the hydrostatic extrusion process is extended to meet the geometry found on residual billets. The transition from inlet to work zone of the process is not considered sharp as in the model of Wilson but as a rounded edge, modelled by a parabolic function. It is shown th

  7. Railcar waste transfer system hydrostatic test report

    Energy Technology Data Exchange (ETDEWEB)

    Ellingson, S.D.

    1997-04-03

    This Acceptance Test Report (ATR) documents for record purposes the field results, acceptance, and approvals of the completed acceptance test per HNF-SD-W417-ATP-001, ''Rail car Waste Transfer System Hydrostatic Test''. The test was completed and approved without any problems or exceptions.

  8. Railcar waste transfer system hydrostatic test

    Energy Technology Data Exchange (ETDEWEB)

    Ellingson, S.D.

    1997-03-31

    Recent modifications have been performed on the T-Plant Railcar Waste Transfer System, This Acceptance Test Procedure (ATP) has been prepared to demonstrate that identified piping welds and mechanical connections incorporated during the modification are of high integrity and are acceptable for service. This will be achieved by implementation of a hydrostatic leak test.

  9. A Multipurpose Device for Some Hydrostatics Questions

    Science.gov (United States)

    Ganci, Salvatore

    2008-01-01

    A number of well-known hydrostatics problems dealing with Archimedes' principle concern a loaded boat floating in a pool. Examples of this sort of problem include: 1. (a) If a stone is thrown overboard from a boat floating in a pool, does the water level in the pool rise, fall, or remain unchanged? (b) If a hole is made in the bottom of the boat…

  10. A Multipurpose Device for Some Hydrostatics Questions

    Science.gov (United States)

    Ganci, Salvatore

    2008-01-01

    A number of well-known hydrostatics problems dealing with Archimedes' principle concern a loaded boat floating in a pool. Examples of this sort of problem include: 1. (a) If a stone is thrown overboard from a boat floating in a pool, does the water level in the pool rise, fall, or remain unchanged? (b) If a hole is made in the bottom of the boat…

  11. 浅谈静液压技术在农业机械中的应用现状与发展趋势%Application status and development trend of hydrostatic technology in agricultural machinery

    Institute of Scientific and Technical Information of China (English)

    陈恒峰; 郭辉; 张学军; 盛会

    2016-01-01

    文中介绍了静液压技术的主要特点,在农业机械中使用静液压技术的优势以及国内外静液压技术在农业机械中应用现状及发展趋势。%This text introduces the main characteristics of hydrostatic technology, explains the advantages of application of hydrostatic technology on agricultural mechinery, reviews the application satus of hydrostatic technology on agricultural mechinery at home and aboard and forcasts the development trend of hydrostatic technology.

  12. Hydrostatic, aerostatic and hybrid bearing design

    CERN Document Server

    Rowe, W Brian

    2012-01-01

    Solve your bearing design problems with step-by-step procedures and hard-won performance data from a leading expert and consultant Compiled for ease of use in practical design scenarios, Hydrostatic, Aerostatic and Hybrid Bearing Design provides the basic principles, design procedures and data you need to create the right bearing solution for your requirements. In this valuable reference and design companion, author and expert W. Brian Rowe shares the hard-won lessons and figures from a lifetime's research and consultancy experience. Coverage includes: Clear e

  13. Mapping Initial Hydrostatic Models in Godunov Codes

    CERN Document Server

    Zingale, M A; Zu Hone, J; Calder, A C; Fryxell, B; Plewa, T; Truran, J W; Caceres, A; Olson, K; Ricker, P M; Riley, K; Rosner, R; Siegel, A; Timmes, F X; Vladimirova, N

    2002-01-01

    We look in detail at the process of mapping an astrophysical initial model from a stellar evolution code onto the computational grid of an explicit, Godunov type code while maintaining hydrostatic equilibrium. This mapping process is common in astrophysical simulations, when it is necessary to follow short-timescale dynamics after a period of long timescale buildup. We look at the effects of spatial resolution, boundary conditions, the treatment of the gravitational source terms in the hydrodynamics solver, and the initialization process itself. We conclude with a summary detailing the mapping process that yields the lowest ambient velocities in the mapped model.

  14. TENDENCIES AND PROSPECTS OF APPLICATION OF HYDROSTATIC-MECHANICAL TRANSMISSION IN CAR- AND TRACTORBUILDING

    Directory of Open Access Journals (Sweden)

    V. Samorodov

    2012-01-01

    Full Text Available Research of advantages and lacks of hydrostatic-mechanical transmission, application of hydrostatic-mechanical transmission, expedience of the use of hydrostatic-mechanical transmission on motor transport and agricultural machines have been done.

  15. The effects of defects on copper melting under hydrostatic and shock loading

    Energy Technology Data Exchange (ETDEWEB)

    Luo, Shengnian [Los Alamos National Laboratory; An, Qi [Los Alamos National Laboratory; Germann, Timothy C [Los Alamos National Laboratory; Han, Li - Bo [USTC

    2009-07-24

    With molecular dynamics (MD) simulations, we investigate the effects of defects on Cu melting under hydrostatic and shock wave loading. We explore preexistent defects including vacancies, stacking faults and grain boundaries, as well as shock-induced defects. Depending on defect characteristics (energy and concentration), defects may have negligible or considerable effects on melting at MD scales However, it is expected that defects have more pronounced effects at heating rates lower than the MD rates.

  16. Radial deformation and stability of single-wall carbon nanotubes under hydrostatic pressure

    OpenAIRE

    HASEGAWA, Masayuki; Nishidate, Kazume

    2006-01-01

    In this paper we have developed a theory of energetics for isolated single-wall carbon nanotubes SWNTsdeformed in the radial direction, and applied this theory to investigate their deformation characteristics andstability under hydrostatic pressure. The starting point of the theory is the strain energy of SWNTs predicted byab initio calculations based on the density functional theory DFT, which shows the same behavior as thatobtained for the continuum elastic shell model. We extend this resul...

  17. 49 CFR 230.36 - Hydrostatic testing of boilers.

    Science.gov (United States)

    2010-10-01

    ... ADMINISTRATION, DEPARTMENT OF TRANSPORTATION STEAM LOCOMOTIVE INSPECTION AND MAINTENANCE STANDARDS Boilers and Appurtenances Pressure Testing of Boilers § 230.36 Hydrostatic testing of boilers. (a) Time of test. The... 49 Transportation 4 2010-10-01 2010-10-01 false Hydrostatic testing of boilers. 230.36 Section...

  18. 49 CFR 178.605 - Hydrostatic pressure test.

    Science.gov (United States)

    2010-10-01

    ... hazardous materials of Packing Group I must be tested to a minimum test pressure of 250 kPa (36 psig). The... 49 Transportation 2 2010-10-01 2010-10-01 false Hydrostatic pressure test. 178.605 Section 178.605... Testing of Non-bulk Packagings and Packages § 178.605 Hydrostatic pressure test. (a) General....

  19. A Simple Explanation of the Classic Hydrostatic Paradox

    Science.gov (United States)

    Kontomaris, Stylianos-Vasileios; Malamou, Anna

    2016-01-01

    An interesting problem in fluid mechanics, with significant educational importance, is the classic hydrostatic paradox. The hydrostatic paradox states the fact that in different shaped containers, with the same base area, which are filled with a liquid of the same height, the applied force by the liquid on the base of each container is exactly the…

  20. Hydrostatic Hamiltonian particle-mesh (HPM) methods for atmospheric modelling

    NARCIS (Netherlands)

    Shin, S.; Reich, S.; Frank, J.E.

    2011-01-01

    We develop a hydrostatic Hamiltonian particle-mesh (HPM) method for efficient long-term numerical integration of the atmosphere. In the HPM method, the hydrostatic approximation is interpreted as a holonomic constraint for the vertical position of particles. This can be viewed as defining a set of v

  1. A Simple Explanation of the Classic Hydrostatic Paradox

    Science.gov (United States)

    Kontomaris, Stylianos-Vasileios; Malamou, Anna

    2016-01-01

    An interesting problem in fluid mechanics, with significant educational importance, is the classic hydrostatic paradox. The hydrostatic paradox states the fact that in different shaped containers, with the same base area, which are filled with a liquid of the same height, the applied force by the liquid on the base of each container is exactly the…

  2. Design for Hydrostatic Bearing of Vertical Type Pump

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Kang Soo; Kim, Sung Kyun; Koo, Gyeong Hoi; Park, Keun Bae [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2015-10-15

    The primary pump of PGSFR(Prototype Gen IV Sodium Fast Reactor) performs an important safety function of circulating the coolant across the core to remove the nuclear heat under all operating conditions of the reactor. Design and selection of materials and manufacturing technology for sodium pumps differ to a large extent from conventional pumps because these pumps operate relatively at high temperatures and have high reliability. In order to provide guide to the shaft at the bottom part, there is a hydrostatic bearing above the impeller level. In this paper, the FEM(Finite Element Method) analysis was performed to evaluate the unbalance force for the rotary shaft for the design of the hydrostatic bearing and the design methodology and procedures for the hydrostatic bearing are established. The hydrostatic bearing of the primary pump of PGSFR is designed. Thus, the design methodology and procedure for the hydrostatic bearing of the vertical type pump are established.

  3. Computer simulations of 3C-SiC under hydrostatic and non-hydrostatic stresses.

    Science.gov (United States)

    Guedda, H Z; Ouahrani, T; Morales-García, A; Franco, R; Salvadó, M A; Pertierra, P; Recio, J M

    2016-03-21

    The response of 3C-SiC to hydrostatic pressure and to several uni- and bi-axial stress conditions is thoroughly investigated using first principles calculations. A topological interpretation of the chemical bonding reveals that the so-called non-covalent interactions enhance only at high pressure while the nature of the covalent Si-C bonding network keeps essentially with the same pattern. The calculated low compressibility agrees well with experimental values and is in concordance with the high structural stability of this polymorph under hydrostatic pressure. Under uniaxial [001] stress, the c/a ratio shows a noticeable drop inducing a closure of the band gap and the emergence of a metallic state around 40 GPa. This behavior correlates with a plateau of the electron localization function exhibiting a roughly constant and non-negligible value surrounding CSi4 and SiC4 covalent bonded units.

  4. The Experimental Analyses of the Effects of the Geometric and Working Parameters on the Circular Hydrostatic Thrust Bearings

    Science.gov (United States)

    Canbulut, Fazıl

    In this paper, the characteristics of disk-type hydrostatic thrust bearings supporting concentric loads; simulating the major bearing/seal parts of axial piston pumps and motors were investigated. An experimental setup was designed to determine the performance of slippers, which are capable of increasing the efficiency of axial piston pumps and motors, for different conditions. The working parameters and the slipper geometry causing the minimum frictional power loss and leakage oil loss were determined. Since slippers affect the performance of the system considerably, the effects of surface roughnesses on lubrication were studied in slippers with varying hydrostatic bearing areas and surface roughness. The results of the study suggest that the frictional power loss and leakage oil loss were caused by the surface roughness, the relative velocity, the size of the hydrostatic bearing area, supply pressure and capillary tube diameter.

  5. History and evidence regarding hydrostatic shock

    CERN Document Server

    Courtney, Michael; 10.1227/NEU.0b013e3182041992

    2011-01-01

    This paper reviews the history and evidence related to remote wounding effects of ballistic pressure waves imparted to tissue by the impact of a bullet. Such remote effects are often referred to as hydraulic or hydrostatic shock. In spite of considerable published evidence and a long history, some medical professionals continue to regard the ability of a bullet to injure tissue that is not directly crushed or stretched as mythical (Jandial R, Reichwage B, Levy M, Duenas V, Sturdivan L. Ballistics for the neurosurgeon. Neurosurgery. 2008:62:472-480.) Early references to these effects date to the 19th century; however, compelling experimental support and medical findings in human case studies did not become available until the late 20th and early 21st century.

  6. Investigation of a hydrostatic azimuth thrust bearing for a large steerable antenna

    Science.gov (United States)

    Rumbarger, J.; Castelli, V.; Rippel, H.

    1972-01-01

    The problems inherent in the design and construction of a hydrostatic azimuth thrust bearing for a tracking antenna of very large size were studied. For a load of 48,000,000 lbs., it is concluded that the hydrostatic bearing concept is feasible, provided that a particular multiple pad arrangement, high oil viscosity, and a particular load spreading arrangement are used. Presently available computer programs and techniques are deemed to be adequate for a good portion of the design job but new integrated programs will have to be developed in the area of the computation of the deflections of the supporting bearing structure. Experimental studies might also be indicated to ascertain the life characteristics of grouting under cyclic loading, and the optimization of hydraulic circuits and pipe sizes to insure the long life operation of pumps with high viscosity oil while avoiding cavitation.

  7. Function and hydrostatics in the telson of the Burgess Shale arthropod Burgessia.

    Science.gov (United States)

    Lin, Jih-Pai

    2009-06-23

    Burgessia bella is a characteristic Burgess Shale arthropod (508 Ma), but the unusual preservation of its telson in both straight and bent modes leads to contradictory interpretations of its function. A reinvestigation of the fossil material, including burial attitudes, combined with a comparison with the decay sequence and mechanics of the telson in living Limulus, demonstrates that the telson of Burgessia was flexible in its relaxed state but could be stiffened in life. Evidence of fluid within the telson indicates that this manoeuvrability was achieved by changes in hydrostatic pressure and muscular control. The dual mode in the Burgessia telson is, to my knowledge, the first documented among fossil arthropods. It indicates that the requirement for a rigid telson, which is resolved by a thick sclerotized cuticle in most arthropods, may first have been achieved by hydrostatic means.

  8. Regulation of paracellular Na+ and Cl(-) conductances by hydrostatic pressure.

    Science.gov (United States)

    Tokuda, Shinsaku; Niisato, Naomi; Nagai, Toshiki; Taruno, Akiyuki; Nakajima, Ken-Ichi; Miyazaki, Hiroaki; Yamada, Toshiki; Hosogi, Shigekuni; Ohta, Mariko; Nishio, Kyosuke; Iwasaki, Yoshinobu; Marunaka, Yoshinori

    2009-09-01

    The effect of hydrostatic pressure on the paracellular ion conductance (Gp) composed of the Na(+) conductance (G(Na)) and the Cl(-) conductance (G(Cl)) has been Investigated. Gp, G(Na) and G(Cl) were time-dependently increased after applying an osmotic gradient generated by NaCl with basolateral hypotonicity. Hydrostatic pressure (1-4cm H2O) applied from the basolateral side enhanced the osmotic gradient-induced increase in Gp, G(Na) and G(Cl) in a magnitude-dependent manner, while the hydrostatic pressure applied from the apical side diminished the osmotic gradient-induced increase in Gp, G(Na) and G(Cl). How the hydrostatic pressure influences Gp, G(Na) and G(Cl) under an isosmotic condition was also investigated. Gp, G(Na) and G(Cl) were stably constant under a condition with basolateral application of sucrose canceling the NaCl-generated osmotic gradient (an isotonic condition). Even under this stable condition, the basolaterally applied hydrostatic pressure drastically elevated Gp, G(Na) and G(Cl), while apically applied hydrostatic pressure had little effect on Gp, G(Na) or G(Cl). Taken together, these observations suggest that certain factors controlled by the basolateral osmolality and the basolaterally applied hydrostatic pressure mainly regulate the Gp, G(Na) and G(Cl).

  9. Quasi-hydrostatic Primitive Equations for Ocean Global Circulation Models

    Institute of Scientific and Technical Information of China (English)

    Carine LUCAS; Madalina PETCU; Antoine ROUSSEAU

    2010-01-01

    Global existence of weak and strong solutions to the quasi-hydrostatic primitive equations is studied in this paper.This model,that derives from the full non-hydrostatic model for geophysical fluid dynamics in the zero-limit of the aspect ratio,is more realistic than the classical hydrostatic model,since the traditional approximation that consists in neglecting a part of the Coriolis force is relaxed.After justifying the derivation of the model,the authors provide a rigorous proof of global existence of weak solutions,and well-posedness for strong solutions in dimension three.

  10. A simple explanation of the classic hydrostatic paradox

    Science.gov (United States)

    Kontomaris, Stylianos-Vasileios; Malamou, Anna

    2016-07-01

    An interesting problem in fluid mechanics, with significant educational importance, is the classic hydrostatic paradox. The hydrostatic paradox states the fact that in different shaped containers, with the same base area, which are filled with a liquid of the same height, the applied force by the liquid on the base of each container is exactly the same. However, if the shape of the container is different, the amount of the liquid (and as a consequence the weight) can greatly vary. In this paper, a simple explanation of the hydrostatic paradox, specifically designed and implemented for educational purposes regarding secondary education, is provided.

  11. Nonlinear Analyses of the Dynamic Properties of Hydrostatic Bearing Systems

    Institute of Scientific and Technical Information of China (English)

    LIU Wei(刘伟); WU Xiujiang(吴秀江); V.A. Prokopenko

    2003-01-01

    Nonlinear analyses of hydrostatic bearing systems are necessary to adequately model the fluid-solid interaction. The dynamic properties of linear and nonlinear analytical models of hydrostatic bearings are compared in this paper. The analyses were based on the determination of the aperiodic border of transient processes with external step loads. The results show that the dynamic properties can be most effectively improved by increasing the hydrostatic bearing crosspiece width and additional pocket volume in a bearing can extend the load range for which the transient process is aperiodic, but an additional restrictor and capacitor (RC) chain must be introduced for increasing damping. The nonlinear analyses can also be used to predict typical design parameters for a hydrostatic bearing.

  12. Hydrodynamic Analysis to Process of Hydrostatic Extrusion for Tungsten Alloy

    Institute of Scientific and Technical Information of China (English)

    Fuchi WANG; Zhaohui ZHANG; Shukui LI

    2001-01-01

    The hydrodynamic analysis to the process of the hydrostatic extrusion for tungsten alloy is carried through the hydrodynamic lubrication theory and Reynolds equation in this paper. The critical velocity equation when the hydrodynamic lubrication conditions appear between the surfaces of the work- piece and the die is obtained, and the relationship between the critical velocity and the extrusion parameters is discussed, which build the theoretical bases to the application of the hydrostatic extrusion for tungsten alloy.

  13. Effect of Superimposed Hydrostatic Pressure on Bendability of Sheet Metals

    Science.gov (United States)

    Chen, X. X.; Wu, P. D.; Lloyd, D. J.

    2010-06-01

    The effect of superimposed hydrostatic pressure on fracture under three-point bending is studied numerically using the finite element method based on the Gurson damage model. It is demonstrated that superimposed hydrostatic pressure significantly increases the bendability and bending fracture strain due to the fact that a superimposed pressure delays or completely eliminates the nucleation, growth and coalescence of microvoids or microcracks. Numerical results are found to be in good agreement with experimental observations.

  14. Hydrostatic pressure effect on micro air bubbles deposited on surfaces with a retreating tip.

    Science.gov (United States)

    Huynh, So Hung; Wang, Jingming; Yu, Yang; Ng, Tuck Wah

    2014-06-01

    The effect of hydrostatic pressure on 6 μL air bubbles formed on micropillar structured PDMS and silicone surfaces using a 2 mm diameter stainless steel tip retreated at 1 mm/s was investigated. Dimensional analysis of the tip retraction process showed the experiments to be conducted in the condition where fluid inertial forces are comparable in magnitude with surface tension forces, while viscous forces were lower. Larger bubbles could be left behind on the structured PDMS surface. For hydrostatic pressures in excess of 20 mm H2O (196 Pa), the volume of bubble deposited was found to decrease progressively with pressure increase. The differences in width of the deposited bubbles (in contact with the substrate) were significant at any particular pressure but marginal in height. The attainable height before rupture reduced with pressure increase, thereby accounting for the reducing dispensed volume characteristic. On structured PDMS, the gaseous bridge width (in contact with the substrate) was invariant with tip retraction, while on silicone it was initially reducing before becoming invariant in the lead up to rupture. With silicone, hence, reductions in the contact width and height were both responsible for reduced volumes with pressure increase. Increased hydrostatic pressure was also found to restrict the growth in contact width on silicone during the stage when air was injected in through the tip. The ability to effect bubble size in such a simple manner may already be harnessed in nature and suggests possibilities in technological applications.

  15. Cosmology and astrophysics from relaxed galaxy clusters - IV: Robustly calibrating hydrostatic masses with weak lensing

    CERN Document Server

    Applegate, D E; Allen, S W; von der Linden, A; Morris, R G; Hilbert, S; Kelly, P L; Burke, D L; Ebeling, H; Rapetti, D A; Schmidt, R W

    2015-01-01

    This is the fourth in a series of papers studying the astrophysics and cosmology of massive, dynamically relaxed galaxy clusters. Here, we use measurements of weak gravitational lensing from the Weighing the Giants project to calibrate Chandra X-ray measurements of total mass that rely on the assumption of hydrostatic equilibrium. This comparison of X-ray and lensing masses provides a measurement of the combined bias of X-ray hydrostatic masses due to both astrophysical and instrumental sources. Assuming a fixed cosmology, and within a characteristic radius (r_2500) determined from the X-ray data, we measure a lensing to X-ray mass ratio of 0.96 +/- 9% (stat) +/- 9% (sys). We find no significant trends of this ratio with mass, redshift or the morphological indicators used to select the sample. In accordance with predictions from hydro simulations for the most massive, relaxed clusters, our results disfavor strong, tens-of-percent departures from hydrostatic equilibrium at these radii. In addition, we find a m...

  16. Toxicity minimization of pipelines hydrostatic tests fluids, stage I: laboratory essays

    Energy Technology Data Exchange (ETDEWEB)

    Lacerda, Jorge A.S.; Penna, Monica de O.; Portela, Daniele B.; Christino, Fernando P.; Silva, Joao L.B. da; Geraldo, Lucia M.L. [Petroleo do Brasileiro S.A. (PETROBRAS), Rio de Janeiro, RJ (Brazil); Mota, Vanessa V.C. [Fundacao Gorceix, Ouro Preto, MG (Brazil); Cravo Junior, Walter [Pontificia Univ. Catolica do Rio de Janeiro (PUC-Rio), RJ (Brazil)

    2009-07-01

    This paper presents the results of the laboratory essays stage of the project for toxicity minimization of pipelines hydrostatic tests fluids. The hydrostatic-hibernation fluid composition most used by PETROBRAS in offshore operations is seawater added with sodium bis sulfite, fluorescein, alquildimetilbenzilamonium chloride, and tetrakis-hydroxymethyl-phosphonium sulfate (THPS). In order to reduce the toxicity of the fluid used in hydrostatic tests, the use of lesser concentrations of THPS was attempted with UV radiation application as a disinfection technique prior to the adding of the fluid's components. The compositions were evaluated in different conditions of temperature use of UV radiation or not and oxygen scavenger adding (presence and absence). The fluids were kept hibernating for 120 days. All the parameters tested after hibernation were compared to fresh from preparation samples (zero time samples). The fluid's characteristics were evaluated by microbiological control and toxicity as well as the THPS residual. Results showed that the UV treatment was more effective in the absence of oxygen scavenger. The temperature acts as a microbial growth control agent, as expected. To large scale operations, a water quality monitoring must be performed previously to any field operations, in order to determinate the best treatment to be used in each case. (author)

  17. Recent Advances in Food Processing Using High Hydrostatic Pressure Technology.

    Science.gov (United States)

    Wang, Chung-Yi; Huang, Hsiao-Wen; Hsu, Chiao-Ping; Yang, Binghuei Barry

    2016-01-01

    High hydrostatic pressure is an emerging non-thermal technology that can achieve the same standards of food safety as those of heat pasteurization and meet consumer requirements for fresher tasting, minimally processed foods. Applying high-pressure processing can inactivate pathogenic and spoilage microorganisms and enzymes, as well as modify structures with little or no effects on the nutritional and sensory quality of foods. The U.S. Food and Drug Administration (FDA) and the U.S. Department of Agriculture (USDA) have approved the use of high-pressure processing (HPP), which is a reliable technological alternative to conventional heat pasteurization in food-processing procedures. This paper presents the current applications of HPP in processing fruits, vegetables, meats, seafood, dairy, and egg products; such applications include the combination of pressure and biopreservation to generate specific characteristics in certain products. In addition, this paper describes recent findings on the microbiological, chemical, and molecular aspects of HPP technology used in commercial and research applications.

  18. SPR Hydrostatic Column Model Verification and Validation.

    Energy Technology Data Exchange (ETDEWEB)

    Bettin, Giorgia [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Lord, David [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Rudeen, David Keith [Gram, Inc. Albuquerque, NM (United States)

    2015-10-01

    A Hydrostatic Column Model (HCM) was developed to help differentiate between normal "tight" well behavior and small-leak behavior under nitrogen for testing the pressure integrity of crude oil storage wells at the U.S. Strategic Petroleum Reserve. This effort was motivated by steady, yet distinct, pressure behavior of a series of Big Hill caverns that have been placed under nitrogen for extended period of time. This report describes the HCM model, its functional requirements, the model structure and the verification and validation process. Different modes of operation are also described, which illustrate how the software can be used to model extended nitrogen monitoring and Mechanical Integrity Tests by predicting wellhead pressures along with nitrogen interface movements. Model verification has shown that the program runs correctly and it is implemented as intended. The cavern BH101 long term nitrogen test was used to validate the model which showed very good agreement with measured data. This supports the claim that the model is, in fact, capturing the relevant physical phenomena and can be used to make accurate predictions of both wellhead pressure and interface movements.

  19. Mechanical stability of iron under hydrostatic stresses

    Science.gov (United States)

    Mishra, K. L.; Thakur, O. P.; Thakur, K. P.

    1991-09-01

    A comprehensive investigation of the mechanics of iron subjected to arbitrary fluid pressure has been carried out. Apart from the classical elastic moduli ( k, μ, and μ') and conventional elastic moduli (Green and stretch moduli) computations are carried out for a family of generalised moduli of which the conventional moduli are just specific members. With the generalised moduli the mechanical stability of iron is investigated through Born criteria. It is found that classical stability, Green stability and stretch stability are all represented uniquely by the present generalised scheme. The definition of effective classical moduli under stresses enabled the amalgamation of the Born criteria of lattice stability into the single classical criteria of lattice stability of cubic crystal under hydrostatic loading environment. Computations are also carried out to investigate the coordinate and stress dependence of Young's modulus of elasticity, Poisson's ratio, mean velocity of elastic wave, and Debye temperature. Surprisingly, it is found that all these properties of solids play an important role in representing the mechanical stability of the solid. The path of uniaxial loading of iron is also investigated along with its internal energy variation on this path. This indicated the existance of stress-free fcc phase of iron on the path of uniaxial deformation at cell length a=3.6444 Å giving enthalpy of transformation (bcc→fcc) of 1.1 kJ/mol in good agreement with experimental results.

  20. Chem-prep PZT95/5 for neutron generator applications : the effect of pore former type and density on the depoling behavior of chemically prepared PZT 95/5 ceramics.

    Energy Technology Data Exchange (ETDEWEB)

    Lockwood, Steven John; Scofield, Timothy W.; Yang, Pin; Voigt, James A.; Tuttle, Bruce Andrew; Moore, Roger Howard

    2003-10-01

    The hydrostatically induced ferroelectric(FE)-to-antiferroelectric(AFE) phase transformation for chemically prepared niobium modified PZT 95/5 ceramics was studied as a function of density and pore former type (Lucite or Avicel). Special attention was placed on the effect of different pore formers on the charge release behavior associated with the FE-to-AFE phase transformation. Within the same density range (7.26 g/cm3 to 7.44 g/cm3), results showed that ceramics prepared with Lucite pore former exhibit a higher bulk modulus and a sharper polarization release behavior than those prepared with Avicel. In addition, the average transformation pressure was 10.7% greater and the amount of polarization released was 2.1% higher for ceramics with Lucite pore former. The increased transformation pressure was attributed to the increase of bulk modulus associated with Lucite pore former. Data indicated that a minimum volumetric transformational strain of -0.42% was required to trigger the hydrostatically induced FE-to-AFE phase transformation. This work has important implications for increasing the high temperature charge output for neutron generator power supply units.

  1. One hundred years of pressure hydrostatics from Stevin to Newton

    CERN Document Server

    Chalmers, Alan F

    2017-01-01

    This monograph investigates the development of hydrostatics as a science. In the process, it sheds new light on the nature of science and its origins in the Scientific Revolution. Readers will come to see that the history of hydrostatics reveals subtle ways in which the science of the seventeenth century differed from previous periods. The key, the author argues, is the new insights into the concept of pressure that emerged during the Scientific Revolution. This came about due to contributions from such figures as Simon Stevin, Pascal, Boyle and Newton. The author compares their work with Galileo and Descartes, neither of whom grasped the need for a new conception of pressure. As a result, their contributions to hydrostatics were unproductive. The story ends with Newton insofar as his version of hydrostatics set the subject on its modern course. He articulated a technical notion of pressure that was up to the task. Newton compared the mathematical way in hydrostatics and the experimental way, and sided with t...

  2. Nonlinear dynamics of hydrostatic internal gravity waves

    Energy Technology Data Exchange (ETDEWEB)

    Stechmann, Samuel N.; Majda, Andrew J. [New York University, Courant Institute of Mathematical Sciences, NY (United States); Khouider, Boualem [University of Victoria, Department of Mathematics and Statistics, Victoria, BC (Canada)

    2008-11-15

    Stratified hydrostatic fluids have linear internal gravity waves with different phase speeds and vertical profiles. Here a simplified set of partial differential equations (PDE) is derived to represent the nonlinear dynamics of waves with different vertical profiles. The equations are derived by projecting the full nonlinear equations onto the vertical modes of two gravity waves, and the resulting equations are thus referred to here as the two-mode shallow water equations (2MSWE). A key aspect of the nonlinearities of the 2MSWE is that they allow for interactions between a background wind shear and propagating waves. This is important in the tropical atmosphere where horizontally propagating gravity waves interact together with wind shear and have source terms due to convection. It is shown here that the 2MSWE have nonlinear internal bore solutions, and the behavior of the nonlinear waves is investigated for different background wind shears. When a background shear is included, there is an asymmetry between the east- and westward propagating waves. This could be an important effect for the large-scale organization of tropical convection, since the convection is often not isotropic but organized on large scales by waves. An idealized illustration of this asymmetry is given for a background shear from the westerly wind burst phase of the Madden-Julian oscillation; the potential for organized convection is increased to the west of the existing convection by the propagating nonlinear gravity waves, which agrees qualitatively with actual observations. The ideas here should be useful for other physical applications as well. Moreover, the 2MSWE have several interesting mathematical properties: they are a system of nonconservative PDE with a conserved energy, they are conditionally hyperbolic, and they are neither genuinely nonlinear nor linearly degenerate over all of state space. Theory and numerics are developed to illustrate these features, and these features are

  3. Hydrostatic Microextrusion of Steel and Copper

    Science.gov (United States)

    Berti, Guido; Monti, Manuel; D'Angelo, Luciano

    2011-05-01

    The paper presents an experimental investigation based on hydrostatic micro extrusion of billets in low carbon steel and commercially pure copper, and the relevant results. The starting billets have a diameter of 0.3 mm and are 5 mm long; a high pressure generator consisting of a manually operated piston screw pump is used to pressurize the fluid up to 4200 bar, the screw pump is connected through a 3-way distribution block to the extrusion die and to a strain gauge high pressure sensor. The sensor has a full scale of 5000 bar and the extrusion pressure is acquired at a sampling rate of 2 kHz by means of an acquisition program written in the LabVIEW environment. Tests have been conducted at room temperature and a lubricant for wire drawing (Chemetall Gardolube DO 338) acts both as the pressurizing fluid and lubricant too. In addition, billets were graphite coated. Different fluid pressures and process durations have been adopted, resulting in different extrusion lengths. The required extrusion pressure is much higher than in non-micro forming operations (this effect is more evident for steel). On the cross section of the extruded parts, hardness and grain size distribution have been measured, the former through Vickers micro hardness (10 g load) tests. In the case of the extrusion of copper, the material behaves as in microdrawing process. In the case of the extrusion of steel, the hardness increases from the core to the surface as in the drawing process, but with lower values. The analysis evidenced the presence of the external layer, but its thickness is about 1/3 of the external layer in the drawn wire and the grains appear smaller than in the layer of the drawn wire. The extruding force required along the extruding direction is higher (22-24 N) than the drawing force along the same direction (12 N): being the material, the reduction ratio, the die sliding length the same in both cases, the higher extrusion force should be caused by a higher tangential friction

  4. Hydrostatic Pressure Promotes Domain Formation in Model Lipid Raft Membranes.

    Science.gov (United States)

    Worcester, David L; Weinrich, Michael

    2015-11-01

    Neutron diffraction measurements demonstrate that hydrostatic pressure promotes liquid-ordered (Lo) domain formation in lipid membranes prepared as both oriented multilayers and unilamellar vesicles made of a canonical ternary lipid mixture for which demixing transitions have been extensively studied. The results demonstrate an unusually large dependence of the mixing transition on hydrostatic pressure. Additionally, data at 28 °C show that the magnitude of increase in Lo caused by 10 MPa pressure is much the same as the decrease in Lo produced by twice minimum alveolar concentrations (MAC) of general anesthetics such as halothane, nitrous oxide, and xenon. Therefore, the results may provide a plausible explanation for the reversal of general anesthesia by hydrostatic pressure.

  5. Hydrostaticity of Pressure Media in Diamond Anvil Cells

    Science.gov (United States)

    You, Shu-Jie; Chen, Liang-Chen; Jin, Chang-Qing

    2009-09-01

    Hydrostaticity under high pressure of several materials from solid, fluid to gas, which are widely used as pressure media in modern high-pressure experiments, is investigated in diamond anvil cells. Judging from the R-line widths and R1 - R2 peak separation of Ruby fluorescence, the inert argon gas is hydrostatic up to about 30 GPa. The behavior of silicon oil is found to be similar to argon at pressures less than 10 GPa, while the widening of R-lines and increase of R1 - R2 peak separation at higher pressure loads indicate a significant degradation of hydrostaticity. Therefore silicon oil is considered as a good pressure medium at pressures less than 10 GPa but poor at higher pressures.

  6. PERSPECTIVE HYDROSTATIC-MECHANICAL TRANSMISSIONS FOR WHEELED TRACTORS OF AGRICULTURAL SETTING

    OpenAIRE

    Samorodov, V.; Bondarenko, A.

    2013-01-01

    The kinematics charts of perspective hydrostatic-mechanical transmission are presented, their basic structural parameters, the size of hydraulic machines of hydrostatic transmission are identified, the kinematic and power parameters of transmissions are determined.

  7. 46 CFR 56.97-30 - Hydrostatic tests (modifies 137.4).

    Science.gov (United States)

    2010-10-01

    ...) Examination for leakage after application of pressure. Following the application of the hydrostatic test... 46 Shipping 2 2010-10-01 2010-10-01 false Hydrostatic tests (modifies 137.4). 56.97-30 Section 56... SYSTEMS AND APPURTENANCES Pressure Tests § 56.97-30 Hydrostatic tests (modifies 137.4). (a) Provision...

  8. Numerical and experimental study of hydrostatic displacement machine

    DEFF Research Database (Denmark)

    Sørensen, Rasmus Mørk; Hansen, Michael; Mouritsen, Ole Ø.

    2012-01-01

    This paper presents a simulation tool to determine the structural deflections and corresponding leakage flow in a hydrostatic displacement motor. The simulation tool is applied to a new motor principle that is categorized as an extreme low-speed high-torque motor with dimensions that calls for at...

  9. High hydrostatic pressure treatment of porcine oocytes induces parthenogenetic activation

    DEFF Research Database (Denmark)

    Lin, Lin; Pribenszky, Csaba; Molnár, Miklós

    2010-01-01

    An innovative technique called high hydrostatic pressure (HHP) treatment has recently been reported to improve the cryosurvival of gametes and embryos in certain mammalian species, including the mouse, pig, and cattle. In the present study the parthenogenetic activation (PA) of pig oocytes caused...

  10. Hydrostatic self-aligning axial/torsional mechanism

    Science.gov (United States)

    O'Connor, Daniel G.; Gerth, Howard L.

    1990-01-01

    The present invention is directed to a self-aligning axial/torsional loading mechanism for testing the strength of brittle materials which are sensitive to bending moments. Disposed inside said self-aligning loading mechanism is a frictionless hydrostatic ball joint with a flexure ring to accommodate torsional loads through said ball joint.

  11. Thermal Conduction in Systems out of Hydrostatic Equilibrium

    CERN Document Server

    Herrera, L; Hernández-Pastora, J L; Martín, J; Martínez, J

    1997-01-01

    We analyse the effects of thermal conduction in a relativistic fluid, just after its departure from hydrostatic equilibrium, on a time scale of the order of thermal relaxation time. It is obtained that the resulting evolution will critically depend on a parameter defined in terms of thermodynamic variables, which is constrained by causality requirements.

  12. Thermal influence of the Couette flow in a hydrostatic spindle on the machining precision

    Science.gov (United States)

    Chen, Dongju; Fan, Jinwei; Li, Haiyong; Wang, Xiaofeng; Zhang, Feihu

    2013-05-01

    Hydrostatic spindles are increasingly used in precision machine tools. Thermal error is the key factor affecting the machining accuracy of the spindle, and research has focused on spindle thermal errors through examination of the influence of the temperature distribution, thermal deformation and spindle mode. However, seldom has any research investigated the thermal effects of the associated Couette flow. To study the heat transfer mechanism in spindle systems, the criterion of the heat transfer direction according to the temperature distribution of the Couette flow at different temperatures is deduced. The method is able to deal accurately with the significant phenomena occurring at every place where thermal energy flowed in such a spindle system. The variation of the motion error induced by thermal effects on a machine work-table during machining is predicated by establishing the thermo-mechanical error model of the hydrostatic spindle for a high precision machine tool. The flow state and thermal behavior of a hydrostatic spindle is analyzed with the evaluated heat power and the coefficients of the convective heat transfer over outer surface of the spindle are calculated, and the thermal influence on the oil film stiffness is evaluated. Thermal drift of the spindle nose is measured with an inductance micrometer, the thermal deformation data 1.35 μm after running for 4 h is consistent with the value predicted by the finite element analysis's simulated result 1.28 μm, and this demonstrates that the simulation method is feasible. The thermal effects on the processing accuracy from the flow characteristics of the fluid inside the spindle are analyzed for the first time.

  13. On the Optimally Controlled Hydrostatic Mechanical Drive in Case of Flywheel Acceleration

    Directory of Open Access Journals (Sweden)

    V. A. Korsunskii

    2016-01-01

    Full Text Available An improving dynamic quality of vehicles and enhanced fuel efficiency are gained thanks to the combined power system (CPS, comprising a main energy source - internal combustion engine (ICE with an attained level of the power source - and an auxiliary energy source, i.e. an energy storage device (a flywheel.To solve this problem was developed a mathematical model of CPS comprising internal combustion engine and flywheel energy storage (FES with stepless drive.The stepless drive of the flywheel is made to be hydrostatic mechanical to raise the system efficiency. To reduce the drive weight and simplify the control system in the hydraulic part of the flywheel drive is used only one hydraulic unit being controlled.The paper presents a kinematic diagram of the track-type vehicle equipped with the CPS that has a hydrostatic mechanical drive of the flywheel and a mechanical transmission.A mathematical model of the system comprising an ICE, hydrostatic mechanical drive, and FES with stepless drive has been developed. This mathematical model was used to study the influence of ICE and flywheel drive parameters on the dynamic characteristics of the system.The paper estimates the impact of flywheel energy consumption, pressure in the hydraulic system, and control parameter of hydrostatic mechanical drive on the charging time of FES.The obtained piecewise linear law to control the regulation parameter of the hydraulic unit allows us to minimize the charging time of the flywheel at the short-term stops and in the parking area of a tracked vehicle equipped with a CPS.The causes affecting the performance of ‘ICE – drive – flywheel’ system in the course of the flywheel acceleration are a restricted maximum power of the engine, as well as a limited generating capacity, and a maximum flywheel drive hydro-system pressure.The obtained results allow us to determine rational parameters of the flywheel and the laws of drive control to provide their further

  14. Dynamic force response of spherical hydrostatic journal bearing for cryogenic applications

    Science.gov (United States)

    Sanandres, Luis

    1994-01-01

    Hydrostatic Journal Bearings (HJB's) are reliable and resilient fluid film rotor support elements ideal to replace roller bearings in cryogenic turbomachinery. HJB' will be used for primary space-power applications due to their long lifetime, low friction and wear, large load capacity, large direct stiffness, and damping force coefficients. An analysis for the performance characteristics of turbulent flow, orifice compensated, spherical hydrostatic journal bearings (HJB's) is presented. Spherical bearings allow tolerance for shaft misalignment without force performance degradation and have also the ability to support axial loads. The spherical HJB combines these advantages to provide a bearing design which could be used efficiently on high performance turbomachinery. The motion of a barotropic liquid on the thin film bearing lands is described by bulk-flow mass and momentum equations. These equations are solved numerically using an efficient CFD method. Numerical predictions of load capacity and force coefficients for a 6 recess, spherical HJB in a LO2 environment are presented. Fluid film axial forces and force coefficients of a magnitude about 20% of the radial load capacity are predicted for the case analyzed. Fluid inertia effects, advective and centrifugal, are found to affect greatly the static and dynamic force performance of the bearing studied.

  15. Changes in Chlorophyll Fluorescence of Rice Mutants Induced by High Hydrostatic Pressure

    Institute of Scientific and Technical Information of China (English)

    BAI Cheng-ke; LI Gui-shuang; PENG Chang-lian; DUAN Jun

    2003-01-01

    Three mutants of rice (Oryza sativa L. ), Mutant 1, Mutant 2and Mutant 3, which were selected by high hydrostatic pressure (75 MPa), and their parent Yuexiangzhan were used to study the changes in chlorophyll fluorescence during different growth stages. In all the three mutants, the function of PSⅡ was improved, Fy/Fm ratio of mutants increased compared to their parent at tillering and heading stage, and φPS Ⅱ also improved except for Mutant 2 at heading stage. Similar to their parent, the mutants exhibited slight photoinhibition at noon and almost complete recovery to initial levels of 6:00 after 18:00 at heading stage. At milking stage, the photoinhibition in the mutants was obvious, and recovered rapidly compared to the parent. Yields of individual plant and grain/straw ratio were also higher in three mutants than the parent. Results indicated that characteristics of chlorophyll fluorescence in leaves of mutants and their photoinhibition in the field had changed. It is suggested that high hydrostatic pressure induction could be applied as a new effective approach in high-yield rice breeding in the future.

  16. Magnetotransport investigations of (Ga,Mn)As/GaAs Esaki diodes under hydrostatic pressure

    Science.gov (United States)

    Gryglas-Borysiewicz, M.; Kwiatkowski, A.; Lemaître, A.; Przybytek, J.; Budzik, K.; Balcerzak, Ł.; Sawicki, M.; Wasik, D.

    2017-02-01

    First investigations of ferromagnetic (Ga,Mn)As/GaAs Esaki diodes under hydrostatic pressure were performed. The I(V) characteristics had bi-exponential character with two excess current regions related to impurity-assisted tunneling, which concealed band-to-band tunneling, resolved only in the logarithmic derivative of current upon bias. A decrease of tunneling current was observed under pressure. This is understood as a combined effect of the increase of the energy gap with pressure and a possible decrease of density of states in the forbidden gap. Tunneling anisotropic magnetocurrent (TAMI) showed nonmonotonic bias dependence, which stays in a reasonable agreement with the theory by Sankowski (2007). The overall character of the TAMI did not change with pressure, however, at negative bias an increase of TAMI was observed and at positive bias the minimum became shallower. The magnetic anisotropy of (Ga,Mn)As valence band subbands seems unaltered by hydrostatic pressure, but more in-depth description of TAMI is necessary to explain the observed pressure variation.

  17. Achieving Textbook Multigrid Efficiency for Hydrostatic Ice Sheet Flow

    KAUST Repository

    Brown, Jed

    2013-03-12

    The hydrostatic equations for ice sheet flow offer improved fidelity compared with the shallow ice approximation and shallow stream approximation popular in today\\'s ice sheet models. Nevertheless, they present a serious bottleneck because they require the solution of a three-dimensional (3D) nonlinear system, as opposed to the two-dimensional system present in the shallow stream approximation. This 3D system is posed on high-aspect domains with strong anisotropy and variation in coefficients, making it expensive to solve with current methods. This paper presents a Newton--Krylov multigrid solver for the hydrostatic equations that demonstrates textbook multigrid efficiency (an order of magnitude reduction in residual per iteration and solution of the fine-level system at a small multiple of the cost of a residual evaluation). Scalability on Blue Gene/P is demonstrated, and the method is compared to various algebraic methods that are in use or have been proposed as viable approaches.

  18. DC Electrical Ageing of XLPE under Hydrostatic Pressure

    Directory of Open Access Journals (Sweden)

    Fadila Benlizidia Lalam

    2017-01-01

    Full Text Available The experimental electrical ageing, of cross-linked polyethylene films 100 μm thick, was investigated under high hydrostatic pressure of 300 bar and at atmospheric pressure. The tests are conducted on direct current (dc for up to 1000 h ageing and at temperature of 70°C. The use of the Weibull statistic, with the estimation of confidence bounds at 90%, has shown that the hydrostatic pressure has a real effect on the lifetime. These lifetime data are qualitatively analyzed with the inverse power model. It was found that thermally activated process is able to describe the pressure effect on the electrical ageing of XLPE.

  19. Electric Hydrostatic Actuation - modular building blocks for industrial applications

    OpenAIRE

    Helbig, Achim; Boes, Christoph

    2016-01-01

    Electro Hydrostatic Actuators (EHA) are emerging as a viable option for industrial machine builders as the design combines the best of both electro-mechanical and electro-hydraulic technologies. The EHA is a highly integrated, compact alternative to traditional hydraulic solutions. Automation engineers moving toward electro-mechanical actuation in pursuit of energy efficiency and environmental cleanliness, will find an EHA an attractive option for high force density actuators. This paper will...

  20. Magnetotransport studies of FeSe under hydrostatic pressure

    Science.gov (United States)

    Tiwari, Brajesh; Jha, Rajveer; Awana, V. P. S.

    2014-06-01

    The discoveries of iron-based superconductors with relatively high transition temperature are under intense experimental and theoretical investigation. Here we present magnetotransport measurements on FeSe superconductor under hydrostatic pressure. We show that in Fe-deficient tetragonal FeSe binary compound, the onset of superconducting transition is almost doubled under 1.98 GPa pressure and the estimated upper critical field of 26.7 Tesla is increased to 47.5 Tesla.

  1. Modeling Microgravity Induced Fluid Redistribution Autoregulatory and Hydrostatic Enhancements

    Science.gov (United States)

    Myers, J. G.; Werner, C.; Nelson, E. S.; Feola, A.; Raykin, J.; Samuels, B.; Ethier, C. R.

    2017-01-01

    Space flight induces a marked cephalad (headward) redistribution of blood and interstitial fluid potentially resulting in a loss of venous tone and reduction in heart muscle efficiency upon introduction into the microgravity environment. Using various types of computational models, we are investigating how this fluid redistribution may induce intracranial pressure changes, relevant to reported reductions in astronaut visual acuity, part of the Visual Impairment and Intracranial Pressure (VIIP) syndrome. Methods: We utilize a lumped parameter cardiovascular system (CVS) model, augmented by compartments comprising the cerebral spinal fluid (CSF) space, as the primary tool to describe how microgravity, and the associated lack of hydrostatic gradient, impacts fluid redistribution. Models of ocular fluid pressures and biomechanics then accept the output of the above model as boundary condition input to allow more detailed, local analysis (see IWS Abstract by Ethier et al.). Recently, we enhanced the capabilities our previously reported CVS model through the implementation of robust autoregulatory mechanisms and a more fundamental approach to the implementation of hydrostatic mechanisms. Modifying the approach of Blanco et al., we implemented auto-regulation in a quasi-static manner, as an averaged effect across the span of one heartbeat. This approach reduced the higher frequency perturbations from the regulatory mechanism and was intended to allow longer simulation times (days) than models that implement within-beat regulatory mechanisms (minutes). A more fundamental approach to hydrostatics was implemented by a quasi-1D approach, in which compartment descriptions include compartment length, orientation and relative position, allowed for modeling of body orientation, relative body positioning and, in the future, alternative gravity environments. At this time the inclusion of hydrostatic mechanisms supplies additional capabilities to train and validate the CVS model

  2. Compression of α-cristobalite under different hydrostatic conditions

    Science.gov (United States)

    Cernok, Ana; Marquardt, Katharina; Bykova, Elena; Liermann, Hanns-Peter; Dubrovinsky, Leonid

    2015-04-01

    The response of α-cristobalite to high-pressure has been a subject of numerous experimental and theoretical studies for more than two decades. The results indicated prolific polymorphism under high pressures, yet no consensus has emerged on what is the sequence of these pressure-induced transformations. In particular, the structure of the high-pressure polymorph that appears above ~10 GPa (hereafter cristobalite X-I), which is believed to be a direct link between the low-pressure (silicon in SiO4 tetrahedra) and the high-pressure (SiO6 octahedra) forms of silica remained elusive. This study examined the response of α-cristobalite when compressed at different levels of hydrostaticity, with the special focus on formation and stability of cristobalite X-I. The structural behavior of cristobalite under pressure was investigated up to ~80 GPa and at ambient temperature. We investigated behavior of single crystals and powders, in either (quasy)-hydrostatic or non-hydrostatic environment. In situ high pressure transformation path and structural behavior was studied by means of Raman spectroscopy and synchrotron X-ray diffraction (XRD). The samples recovered after pressure release were additionally investigated by transmission electron microscopy (TEM). Low- or α-cristobalite responds differently to high pressure depending on the degree of the hydrostaticity. The highest attainable hydrostaticity preserves the initial structure of cristobalite at least up to ~15 GPa. When the crystal experiences even slight stresses during an experiment, transformation sequence leads to cristobalite X-I - a monoclinic polymorph with silicon in octahedral coordination. This polymorph belongs to the family of the high-pressure silica phases that are comprised of distorted close-packed array of oxygen ions in which silicon atoms fully or partially occupy octahedral sites. The reflections collected on a single crystal at ~11 GPa can be indexed by a monoclinic unit cell a=6.658(9) Å, b=4

  3. Mixed Lubrication Simulation of Hydrostatic Spherical Bearings for Hydraulic Piston Pumps and Motors

    Science.gov (United States)

    Kazama, Toshiharu

    Mixed and fluid film lubrication characteristics of hydrostatic spherical bearings for swash-plate-type axial piston pumps and motors are studied theoretically under non-steady-state conditions. The basic equations incorporating interference and contact of surface roughness are derived fundamentally through combination of the GW and PC models. Furthermore, a programming code that is applicable to the caulked-socket-type and open-socket-type bearings is developed. Effects of caulking, operating conditions, and the bearing dimension on the motion of the sphere and tribological performance of the bearings are examined. Salient conclusions are the following: The sphere's eccentricity increases in the low supply pressure period. The time-lag of the load change engenders greater motion of the sphere. Caulking of the bearing socket suppresses the sphere's motion. The bearing stiffness increases and power loss decreases for smaller recess angles. Minimum power loss is given under the condition that the bearing socket radius nearly equals the equivalent load radius.

  4. Innovation in the development and improvement of meat products: High hydrostatic pressures

    Directory of Open Access Journals (Sweden)

    Gallardo, Claudia

    2015-08-01

    Full Text Available One focus of interest in the development of products and processes of the food industry is related to the reduction in the use of additives that could have negative effects on consumer health. This view called cleaning nutritional label is aimed at the partial or total substitution of additives by other factors that do not have these negative effects and maintain the safety and quality of the products processed. The high hydrostatic pressure (HHP is one of the new conservation factors used to reduce the content of sodium chloride and nitrites in meat products. HHP technology is increasingly being applied to produce safe with high quality and minimal effects on food sensory and nutritional characteristics. In this context the present review describes the current status in the development of processed meat products, specifically ham, as well as alternative use of high pressure in the product and its future development prospects.

  5. A three-dimensional spectral element model for the solution of the hydrostatic primitive equations

    CERN Document Server

    Iskandarani, M; Levin, J C

    2003-01-01

    We present a spectral element model to solve the hydrostatic primitive equations governing large-scale geophysical flows. The highlights of this new model include unstructured grids, dual h-p paths to convergence, and good scalability characteristics on present day parallel computers including Beowulf-class systems. The behavior of the model is assessed on three process-oriented test problems involving wave propagation, gravitational adjustment, and nonlinear flow rectification, respectively. The first of these test problems is a study of the convergence properties of the model when simulating the linear propagation of baroclinic Kelvin waves. The second is an intercomparison of spectral element and finite-difference model solutions to the adjustment of a density front in a straight channel. Finally, the third problem considers the comparison of model results to measurements obtained from a laboratory simulation of flow around a submarine canyon. The aforementioned tests demonstrate the good performance of th...

  6. THE EFFECT OF OIL CAVITY DEPTH ON TEMPERATURE FIELD IN HEAVY HYDROSTATIC THRUST BEARING

    Institute of Scientific and Technical Information of China (English)

    SHAO Jun-peng; DAI Chun-xi; ZHANG Yan-qin; YU Xiao-dong; XU Xiao-qiu; WANG Yun-fei

    2011-01-01

    For a heavy hydrostatic bearing with a high linear velocity,the results of numerical calculations often differ from practical conditions if the viscosity is considered as constant.In this article,the influence of the oil cavity depth on the temperature field in the heavy hydrostatic bearing is discussed in the context of variable viscosity.The viscosity-temperature relations for the gap oil film are first established by fitting B-Spline curves,then,numerical calculations for the temperature field in the heavy hydrostatic bearing of different oil cavity depths are carried out based on Finite Volume Method (FVM) under the same rotating speed,and the influence of the oil cavity depth on the temperature distribution in the gap oil film of the hydrostatic bearing is discussed.The results of numerical calculations provide the temperature distribution state inside the hydrostatic bearing,which would help the selection and the design of hydrostatic bearings in engineering practice.

  7. The importance of pre-planning for large hydrostatic test programs

    Energy Technology Data Exchange (ETDEWEB)

    Bennett, Andrew Keith [WorleyParsons Calgary, Calgary, AB (Canada); Wong, Everett Clementi [Enbridge Pipelines Inc., Edmonton, AB (Canada)

    2010-07-01

    During the design phase of a pipeline project, large hydrostatic test programs are required to locate and secure water sources. Many companies complete hydrostatic test planning through high level desktop analysis, however this technique can result in important unplanned costs and schedule delays. The aim of this paper is to assess the cost benefits of pre-planning large hydrostatic test programs versus the costs of unplanned delays in the execution of hydrostatic testing. This comparison was based on the successful application of pre-planning of 57 mainline hydrostatic tests in the construction of the Line 4 Extension and Alberta Clipper Expansion oil pipelines by Enbridge Pipelines Inc. Results showed that costs of delays and uncertainty during construction far outweigh the costs of pre-planning. This study highlighted that pre-planning for large hydrostatic test programs should be carried out in the execution of large pipeline projects to ensure success.

  8. ZF cPower – Hydrostatic-Mechanical Powersplit Transmission for Construction and Forest Machinery

    OpenAIRE

    Legner, Jürgen; Rebholz, Wolfgang; Morrison, Robert

    2016-01-01

    Until recently, hydrostatic-mechanical power split CVT drivelines have not found a place in construction machinery. The majority of these vehicles still use hydrodynamic powershift transmissions, full-hydrostatic transmissions or mechanical direct-shift transmissions. Hydrostatic drive lines are widely used in construction machinery possessing lower engine power. The upper power range is dominated by hydrodynamic powershift transmissions. Decisions made by vehicle manufacturers about which dr...

  9. THREE-DIMENSIONAL NON-HYDROSTATIC MODEL FOR FREE-SURFACE FLOWS WITH UNSTRUCTURED GRID

    Institute of Scientific and Technical Information of China (English)

    AI Cong-fang; JIN Sheng

    2008-01-01

    The three-dimensional Navier-Stokes equations were solved with the fractional step method where the hydrostatic pressure component was determined first, while the non-hydrostatic component of the pressure was computed from the pressure Poisson equation in which the coefficient matrix is positive definite and symmetric. The eddy viscosity was calculated from the efficient k-ε turbulence model. The resulting model is computationally efficient and unrestricted to the CFL condition. Computations with and without hydrostatic approximation were compared for the same cases to test the validity of the conventional hydrostatic pressure assumption. The model was verified against analytical solutions and experimental data, with excellent agreement.

  10. Evaluation of a hybrid hydrostatic bearing for cryogenic turbopump application

    Science.gov (United States)

    Spica, P. W.; Hannum, N. P.; Meyer, S. D.

    1986-01-01

    A hybrid hydrostatic bearing was designed to operate in liquid hydrogen at speeds to 80,000 rpm and radial loads to 440 n (100 lbf). The bearing assembly consisted of a pair of 20-mm angular-contact ball bearings encased in a journal, which was in turn supported by a fluid film of liquid hydrogen. The size and operating conditions of the bearing were selected to be compatible with the operating requirements of an advanced technology turbopump. Several test parameters were varied to characterize the bearing's steady-state operation. The rotation of the tester shaft was varied between 0 and 80,000 rpm. Bearing inlet fluid pressure was varied between 2.07 and 4.48 MPa (300 and 650 psia), while the fluid sump pressure was independently varied between 0.34 and 2.07 MPa (50 and 300 psia). The maximum radial load applied to the bearing was 440 N (110 lbf). Measured hybrid-hydrostatic-bearing stiffness was 1.5 times greater than predicted, while the fluid flow rate through the bearing was 35 to 65 percent less than predicted. Under two-phase fluid conditions, the stiffness was even greater and the flow rate was less. The optimal pressure ratio for the bearing should be between 0.2 and 0.55 depending on the balance desired between bearing efficiency and stiffness. Startup and shutdown cyclic tests were conducted to demonstrate the ability of the hybrid-hydrostatic-bearing assembly to survive at least a 300-firing-duty cycle. For a typical cycle, the shaft was accelerated to 50,000 rpm in 1.8 sec. The bearing operated for 337 start-stop cycles without failure.

  11. Pasteurization of food by hydrostatic high pressure: chemical aspects.

    Science.gov (United States)

    Tauscher, B

    1995-01-01

    Food pasteurized by hydrostatic high pressure have already been marketed in Japan. There is great interest in this method also in Europe and USA. Temperature and pressure are the essential parameters influencing the state of substances including foods. While the influence of temperature on food has been extensively investigated, effects of pressure, also in combination with temperature, are attracting increasing scientific attention now. Processes and reactions in food governed by Le Chatelier's principle are of special interest; they include chemical reactions of both low- and macromolecular compounds. Theoretical fundamentals and examples of pressure affected reactions are presented.

  12. Multi-Pulsed High Hydrostatic Pressure Treatment of Foods

    OpenAIRE

    Sencer Buzrul

    2015-01-01

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

  13. Radial deformation and stability of single-wall carbon nanotubes under hydrostatic pressure

    Science.gov (United States)

    Hasegawa, Masayuki; Nishidate, Kazume

    2006-09-01

    In this paper we have developed a theory of energetics for isolated single-wall carbon nanotubes (SWNTs) deformed in the radial direction, and applied this theory to investigate their deformation characteristics and stability under hydrostatic pressure. The starting point of the theory is the strain energy of SWNTs predicted by ab initio calculations based on the density functional theory (DFT), which shows the same behavior as that obtained for the continuum elastic shell model. We extend this result for inflated SWNTs with circular cross section to calculate the deformation energy of a deformed SWNT without performing further DFT calculations. This extension is then complemented by a van der Waals interaction, which is not fully taken into account in the DFT approximations currently in use but becomes important in highly deformed tubes. We find that the minimum pressure, P1 , for the radial deformation to occur is proportional to the inverse cube of tube diameter, D , in agreement with the recent theoretical predictions as well as the classical theory of buckling. The radial deformation of SWNTs with Dpressure and they hardly collapse. On the other hand, SWNTs with D>2.5nm show a plastic deformation and collapse if the applied hydrostatic pressure exceeds a critical value, which is about 30 40% higher than P1 and also varies as D-3 though approximately. These SWNTs with large D collapse when the cross-sectional area is about 60% reduced with respect to the circular one. It is also found that for SWNTs with D>7.0nm , the plastically deformed (collapsed) state is more stable than the inflated one. This critical value of D is somewhat larger than previously predicted.

  14. Glycine insertion makes yellow fluorescent protein sensitive to hydrostatic pressure.

    Directory of Open Access Journals (Sweden)

    Tomonobu M Watanabe

    Full Text Available Fluorescent protein-based indicators for intracellular environment conditions such as pH and ion concentrations are commonly used to study the status and dynamics of living cells. Despite being an important factor in many biological processes, the development of an indicator for the physicochemical state of water, such as pressure, viscosity and temperature, however, has been neglected. We here found a novel mutation that dramatically enhances the pressure dependency of the yellow fluorescent protein (YFP by inserting several glycines into it. The crystal structure of the mutant showed that the tyrosine near the chromophore flipped toward the outside of the β-can structure, resulting in the entry of a few water molecules near the chromophore. In response to changes in hydrostatic pressure, a spectrum shift and an intensity change of the fluorescence were observed. By measuring the fluorescence of the YFP mutant, we succeeded in measuring the intracellular pressure change in living cell. This study shows a new strategy of design to engineer fluorescent protein indicators to sense hydrostatic pressure.

  15. Study of glass hydrometer calibration by hydrostatic weighting

    Science.gov (United States)

    Chen, Chaoyun; Wang, Jintao; Li, Zhihao; Zhang, Peiman

    2016-01-01

    Glass hydrometers are simple but effective instruments for measuring the density of liquids. Glass hydrometers calibration based on the Archimedes law, using silicon ring as a reference standard solid density, n-tridecane with density stability and low surface tension as the standard working liquid, based on hydrostatic weighing method designs a glass hydrometer calibration system. Glass hydrometer calibration system uses CCD image measurement system to align the scale of hydrometer and liquid surface, with positioning accuracy of 0.01 mm. Surface tension of the working liquid is measured by Whihemy plate. According to twice glass hydrometer weighing in the air and liquid can calculate the correction value of the current scale. In order to verify the validity of the principle of the hydrostatic weighing method of glass hydrometer calibration system, for measuring the density range of (770-790) kg/m3, with a resolution of 0.2 kg/m3 of hydrometer. The results of measurement compare with the Physikalisch-Technische Bundesanstalt(PTB) ,verifying the validity of the calibration system.

  16. Opportunities of hydrostatically coupled dielectric elastomer actuators for haptic interfaces

    Science.gov (United States)

    Carpi, Federico; Frediani, Gabriele; De Rossi, Danilo

    2011-04-01

    As a means to improve versatility and safety of dielectric elastomer actuators (DEAs) for several fields of application, so-called 'hydrostatically coupled' DEAs (HC-DEAs) have recently been described. HC-DEAs are based on an incompressible fluid that mechanically couples a DE-based active part to a passive part interfaced to the load, so as to enable hydrostatic transmission. This paper presents ongoing developments of HC-DEAs and potential applications in the field of haptics. Three specific examples are considered. The first deals with a wearable tactile display used to provide users with tactile feedback during electronic navigation in virtual environments. The display consists of HCDEAs arranged in contact with finger tips. As a second example, an up-scaled prototype version of an 8-dots refreshable cell for dynamic Braille displays is shown. Each Braille dot consists of a miniature HC-DEA, with a diameter lower than 2 mm. The third example refers to a device for finger rehabilitation, conceived to work as a sort of active version of a rehabilitation squeezing ball. The device is designed to dynamically change its compliance according to an electric control. The three examples of applications intend to show the potential of the new technology and the prospective opportunities for haptic interfaces.

  17. Collapse of composite tubes under uniform external hydrostatic pressure

    Science.gov (United States)

    Smith, P. T.; Ross, C. T. F.; Little, A. P. F.

    2009-08-01

    This paper describes an experimental and a theoretical investigation into the collapse of 22 circular cylindrical composite tubes under external hydrostatic pressure. The investigations were on the collapse of fibre reinforced plastic tube specimens made from a mixture of three carbon and two E-glass fibre layers. The theoretical investigations were carried out using an in-house finite element computer program called BCLAM, together with the commercial computer package, namely ANSYS. It must be emphasised here that BS 5500 does not appear to exclusively cater for the buckling of composite shells under external hydrostatic pressure, so the work presented here is novel and should be useful to industry. The experimental investigations showed that the composite specimens behaved similarly to isotropic materials previously tested, in that the short vessels collapsed through axisymmetric deformation while the longer tubes collapsed through non-symmetric bifurcation buckling. Furthermore it was discovered that the models failed at changes of the composite lay-up due to the manufacturing process of these models. These changes seemed to be the weak points of the specimens.

  18. Collapse of composite tubes under uniform external hydrostatic pressure

    Energy Technology Data Exchange (ETDEWEB)

    Smith, P T; Ross, C T F; Little, A P F, E-mail: Carl.ross@ntlworld.co [University of Portsmouth, Portsmouth, PO1 3DJ (United Kingdom)

    2009-08-01

    This paper describes an experimental and a theoretical investigation into the collapse of 22 circular cylindrical composite tubes under external hydrostatic pressure. The investigations were on the collapse of fibre reinforced plastic tube specimens made from a mixture of three carbon and two E-glass fibre layers. The theoretical investigations were carried out using an in-house finite element computer program called BCLAM, together with the commercial computer package, namely ANSYS. It must be emphasised here that BS 5500 does not appear to exclusively cater for the buckling of composite shells under external hydrostatic pressure, so the work presented here is novel and should be useful to industry. The experimental investigations showed that the composite specimens behaved similarly to isotropic materials previously tested, in that the short vessels collapsed through axisymmetric deformation while the longer tubes collapsed through non-symmetric bifurcation buckling. Furthermore it was discovered that the models failed at changes of the composite lay-up due to the manufacturing process of these models. These changes seemed to be the weak points of the specimens.

  19. Inelastic compaction, dilation and hysteresis of sandstones under hydrostatic conditions

    Science.gov (United States)

    Shalev, Eyal; Lyakhovsky, Vladimir; Ougier-Simonin, Audrey; Hamiel, Yariv; Zhu, Wenlu

    2014-05-01

    Sandstones display non-linear and inelastic behaviour such as hysteresis when subjected to cyclic loading. We present three hydrostatic compaction experiments with multiple loading-unloading cycles on Berea and Darley Dale sandstones and explain their hysteretic behaviour using non-linear inelastic compaction and dilation. Each experiment included eight to nine loading-unloading cycles with increasing maximum pressure in each subsequent cycle. Different pressure-volumetric strain relations during loading and unloading were observed. During the first cycles, under relatively low pressures, not all of the volumetric strain is recovered at the end of each cycle whereas at the last cycles, under relatively high pressures, the strain is recovered and the pressure-volumetric strain hysteresis loops are closed. The observed pressure-volumetric strain relations are non-linear and the effective bulk modulus of the sandstones changes between cycles. Observations are modelled with two inelastic deformation processes: irreversible compaction caused by changes in grain packing and recoverable compaction associated with grain contact adhesion, frictional sliding on grains or frictional sliding on cracks. The irreversible compaction is suggested to reflect rearrangement of grains into a more compact mode as the maximum pressure increases. Our model describes the `inelastic compaction envelope' in which sandstone sample will follow during hydrostatic loading. Irreversible compaction occurs when pressure is greater than a threshold value defined by the `inelastic compaction envelope'.

  20. Effect of high hydrostatic pressure on overall quality parameters of watermelon juice.

    Science.gov (United States)

    Liu, Y; Zhao, X Y; Zou, L; Hu, X S

    2013-06-01

    High hydrostatic pressure as a kind of non-thermal processing might maintain the quality of thermo-sensitive watermelon juice. So, the effect of high hydrostatic pressure treatment on enzymes and quality of watermelon juice was investigated. After high hydrostatic pressure treatment, the activities of polyphenol oxidase, peroxidase, and pectin methylesterase of juice decreased significantly with the pressure (P  0.05). No significant difference was observed in lycopene and total phenolics after high hydrostatic pressure treatment when compared to the control (P > 0.05). Cloudiness and viscosity increased with pressure (P  0.05). a*- and b*-value both unchanged after high hydrostatic pressure treatment (P > 0.05) while L*-value increased but the values had no significant difference among treated juices. Browning degree after high hydrostatic pressure treatment decreased with increase in pressure and treatment time (P high hydrostatic pressure had little effect on color of juice. The results of this study demonstrated the efficacy of high hydrostatic pressure in inactivating enzymes and maintaining the quality of watermelon juice.

  1. Influence of the hydrostatic stress component on critical surface expansion in forging compound products

    DEFF Research Database (Denmark)

    Vorm, T; Bay, Niels; Wanheim, Tarras

    1974-01-01

    of a superimposed hydrostatic pressure on the critical surface expansion during a forging process. The critical surface expansion appears to decrease with increasing hydrostatic pressure. This may be due to the fact that the close contact between the materials necessary to obtain bonding is created by a micro...

  2. Hydrostatic fluid pressure in the vestibular organ of the guinea pig

    NARCIS (Netherlands)

    Park, Jonas J. -H.; Boeven, Jahn J.; Vogel, Stefan; Leonhardt, Steffen; Wit, Hero P.; Westhofen, Martin

    2012-01-01

    Since inner ear hair cells are mechano-electric transducers the control of hydrostatic pressure in the inner ear is crucial. Most studies analyzing dynamics and regulation of inner ear hydrostatic pressure performed pressure measurements in the cochlea. The present study is the first one reporting a

  3. Physiological damages of Listeria monocytogenes treated by high hydrostatic pressure.

    Science.gov (United States)

    Ritz, M; Tholozan, J L; Federighi, M; Pilet, M F

    2002-11-15

    High hydrostatic pressure is a new food preservation technology known for its capacity to inactivate spoilage and pathogenic microorganisms. This study investigated the damages inflicted on Listeria monocytogenes cells treated by high pressure for 10 min at 400 MPa in pH 5.6 citrate buffer. Under these conditions, no cell growth occurred after 48 h on plate count agar. Scanning electron microscopy (SEM) revealed that cellular morphology was not really affected. Measuring propidium iodide (PI) staining followed by flow cytometry demonstrated that membrane integrity was damaged in a small part of the population, although the membrane potential evaluated by oxonol fluorescence or measured by analytical methods was reduced from - 86 to - 5 mV. These results for the first time showed that such combined methods as fluorescent dyes monitored by flow cytometry and physiological activity measurements provide valuable indications on cellular viability.

  4. High hydrostatic pressure tolerance of four different anhydrobiotic animal species.

    Science.gov (United States)

    Horikawa, Daiki D; Iwata, Ken-Ichi; Kawai, Kiyoshi; Koseki, Shigenobu; Okuda, Takashi; Yamamoto, Kazutaka

    2009-03-01

    High hydrostatic pressure (HHP) can induce physical changes in DNA, proteins, and lipids, causing lethal or sublethal damage to organisms. However, HHP tolerance of animals has not been studied sufficiently. In this study, HHP tolerance of four species of invertebrate anhydrobiotes (the tardigrade Milnesium tardigradum, a nematode species in the family Plectidae, larvae of Polypedilum vanderplanki, and cysts of Artemia franciscana), which have the potential to enter anhydrobiosis upon desiccation, were investigated by exposing them to 1.2 GPa for 20 minutes. This exposure killed the anhydrobiotes in their ordinary hydrated state, but did not affect their survival in the anhydrobiotic state. The results indicated that the hydrated anhydrobiotes were vulnerable to HHP, but that HHP of 1.2 GPa was not sufficient to kill them in anhyrdobiosis.

  5. Hydrostatic equilibrium and stellar structure in f(R)-gravity

    CERN Document Server

    Capozziello, S; Odintsov, S D; Stabile, A

    2011-01-01

    We investigate the hydrostatic equilibrium of stellar structure by taking into account the modi- fied La\\'e-Emden equation coming out from f(R)-gravity. Such an equation is obtained in metric approach by considering the Newtonian limit of f(R)-gravity, which gives rise to a modified Poisson equation, and then introducing a relation between pressure and density with polytropic index n. The modified equation results an integro-differential equation, which, in the limit f(R) \\rightarrow R, becomes the standard La\\'e-Emden equation. We find the radial profiles of gravitational potential by solving for some values of n. The comparison of solutions with those coming from General Relativity shows that they are compatible and physically relevant.

  6. Numerical and Experimental Study of Friction Loss in Hydrostatic Motor

    DEFF Research Database (Denmark)

    Sørensen, Rasmus Mørk; Hansen, Michael R.; Mouritsen, Ole Ø.

    2012-01-01

    . This is done by means of additional pressure volumes that in uence the stator de ection. These pressures are referred to as compensation pressures and the main emphasis is on friction or torque loss modeling of the motor as a function of the compensation pressures and the high and low pressures related...... to the load torque. The torque loss modeling is identied as a Stribeck curve which depends on gap height. The asperity friction is decreasing exponentially with an increase in gap height. The parameters of the torque loss model are based on prototype measurements that include the structural de ections......This paper presents a numerical and experimental study of the losses in a hydrostatic motor principle. The motor is designed so that the structural de ections and lubricating regimes between moving surfaces and, subsequently, the leakage and friction losses, can be controlled during operation...

  7. APPLICATIONS OF HIGH HYDROSTATIC PRESSURE IN THE FOOD INDUSTRY

    Directory of Open Access Journals (Sweden)

    Yahya TÜLEK

    2006-03-01

    Full Text Available Nowadays, thermal processes are used in order to preserve food from microbiologic and enzymatic changes and extend the shelf life. Thermal treatments are particularly safe, assures a total inactivation of vegetative microorganism cells and spore. On the other hand it present some disadvantages related to the high temperature employed, such as denaturation of proteins, vitamins, productions of toxic compound, undesirable organoleptic features. 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. Present article represents studies on application aspects and effects of high hydrostatic pressure in foods.

  8. Ultrahigh hydrostatic pressure extraction of flavonoids from Epimedium koreanum Nakai

    Science.gov (United States)

    Hou, Lili; Zhang, Shouqin; Dou, Jianpeng; Zhu, Junjie; Liang, Qing

    2011-02-01

    Herba Epimedii is one of the most famous Chinese herbal medicines listed in the Pharmacopoeia of the People's Republic of China, as one of the representatives of traditional Chinese herb, it has been widely applied in the field of invigorate the kidney and strengthen 'Yang'. The attention to Epimedium extract has more and more increased in recent years. In this work, a novel extraction technique, ultra-high hydrostatic pressure extraction (UPE) technology was applied to extract the total flavonoids of E. koreanum. Three factors (pressure, ethanol concentration and extraction time) were chosen as the variables of extraction experiments, and the optimum UPE conditions were pressure 350 MPa; ethanol concentration 50% (v/v); extraction time 5 min. Compared with Supercritical CO2 extraction, Reflux extraction and Ultrasonic-assisted extraction, UPE has excellent advantages (shorter extraction time, higher yield, better antioxidant activity, lower energy consumption and eco-friendly).

  9. Effect of hydrostatic pressure on elastic properties of ZDTP tribofilms

    CERN Document Server

    Demmou, Karim; Loubet, Jean-Luc

    2007-01-01

    Previous studies have shown that the elastic properties of Zinc Dialkyl-dithiophosphate (ZDTP) tribofilms measured by nanoindentation increase versus applied pressure (Anvil effect) [1, 2]. The aim of this paper is to demonstrate that, up to 8 GPa, this increase is a reversible phenomenon. A ZDTP tribofilm has been produced on "AISI 52100" steel substrate using a Cameron-Plint tribometer. After its formation, a hydrostatic pressure of about 8 GPa was applied during one minute on the tribofilm using a large radius steel ball ("Brinell-like" test). Nanoindentation tests were performed with a Berkovich tip on pads in order to measure and compare the mechanical properties of the tribofilm inside and outside the macroscopic plastically deformed area. Careful AFM observations have been carried out on each indent in order to take into account actual contact area. No difference in elastic properties was observed between the two areas: tribofilm modulus and pressure sensitivity are the same inside and outside the resi...

  10. Multi-Pulsed High Hydrostatic Pressure Treatment of Foods

    Directory of Open Access Journals (Sweden)

    Sencer Buzrul

    2015-05-01

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

  11. Investigating the nucleation of protein crystals with hydrostatic pressure

    Energy Technology Data Exchange (ETDEWEB)

    Kadri, A [Departement ' Mecanismes et Macromolecules de la Synthese Proteique et Cristallogenese' UPR 9002, Institut de Biologie Moleculaire et Cellulaire du CNRS, 15 rue Rene Descartes, F-67084 Strasbourg Cedex (France); Damak, M [Laboratoire de Chimie des Substances Naturelles, Faculte des Sciences de Sfax, BP 802, 3018 Sfax (Tunisia); Jenner, G [Laboratoire de Piezochimie Organique, UMR 7123, Faculte de Chimie, Universite Louis Pasteur, 1 rue Blaise Pascal, F-67008 Strasbourg Cedex (France); Lorber, B [Departement ' Mecanismes et Macromolecules de la Synthese Proteique et Cristallogenese' UPR 9002, Institut de Biologie Moleculaire et Cellulaire du CNRS, 15 rue Rene Descartes, F-67084 Strasbourg Cedex (France); Giege, R [Departement ' Mecanismes et Macromolecules de la Synthese Proteique et Cristallogenese' UPR 9002, Institut de Biologie Moleculaire et Cellulaire du CNRS, 15 rue Rene Descartes, F-67084 Strasbourg Cedex (France)

    2003-12-17

    Hydrostatic pressure in the 0.1-75 MPa range has been used as a non-invasive tool to study the crystallization process of the tetragonal crystal form of the protein thaumatin (M{sub r} 22 200). Crystals were prepared within agarose gel and at temperatures in the range from 283 to 303 K. The solubility, i.e. the concentration of soluble macromolecules remaining in equilibrium with the crystals, decreases when the pressure increases and when the temperature decreases. High pressure was used to probe the nucleation behaviour of thaumatin. The pressure dependence of the nucleation rate leads to an activation volume of -46.5cm{sup 3} mol{sup -1}. It is shown that an increase in pressure decreases the enthalpy, the entropy and the free energy of crystallization of thaumatin. The data are discussed in the light of the results of crystallographic analyses and of the structure of the protein.

  12. Energy control strategy for parallel hydrostatic transmission hybrid vehicles

    Institute of Scientific and Technical Information of China (English)

    SUN Hui; JIANG Ji-hai; WANG Xin

    2009-01-01

    Aimed at the relatively lower energy density and complicated coordinating operation between two power sources, a special energy control strategy is required to maximize the fuel saving potential. Then a new type of configuration for hydrostatic transmission hybrid vehicles (PHHV) and the selection criterion for impor-tant components are proposed. Based on the optimization of planet gear transmission ratio and the analysis of op-timal energy distribution for the proposed PHHV on a representative urban driving cycle, a fuzzy torque control strategy and a braking energy regeneration strategy are designed and developed to realize the real-time control of energy for the proposed PHHV. Simulation results demonstrate that the energy control strategy effectively im-proves the fuel economy of PHHV.

  13. Role of osmotic and hydrostatic pressures in bacteriophage genome ejection

    CERN Document Server

    Lemay, Serge G; Molineux, Ian J

    2012-01-01

    A critical step in the bacteriophage life cycle is genome ejection into host bacteria. The ejection process for double-stranded DNA phages has been studied thoroughly \\textit{in vitro}, where after triggering with the cellular receptor the genome ejects into a buffer. The experimental data have been interpreted in terms of the decrease in free energy of the densely packed DNA associated with genome ejection. Here we detail a simple model of genome ejection in terms of the hydrostatic and osmotic pressures inside the phage, a bacterium, and a buffer solution/culture medium. We argue that the hydrodynamic flow associated with the water movement from the buffer solution into the phage capsid and further drainage into the bacterial cytoplasm, driven by the osmotic gradient between the bacterial cytoplasm and culture medium, provides an alternative mechanism for phage genome ejection \\textit{in vivo}; the mechanism is perfectly consistent with phage genome ejection \\textit{in vitro}.

  14. High hydrostatic pressure: Can we trust published data?

    Directory of Open Access Journals (Sweden)

    Németh Cs.

    2015-01-01

    Full Text Available There are numerous new technologies whose implementation in food industry is hampered by the fact that people hesitate to invest in expensive systems which they cannot be sure will work or at least are questionable in terms of a given product. Until recently, preservation by HHP, high hydrostatic pressure, was such a technology, and still is today in some branches of the food industry. Investigations were conducted to answer the question of whether the literature, the laboratory, and the industrial (or at least pilot plant measurements and results agree with one another. We compared the literature data with two HHP systems which were significantly different in terms of treatment capacity, but their efficiency in killing microbes was studied under the same treatment parameters. Our results show that in nearly all cases only minimal differences exist between the data in the literature and the measurements taken on the two appliances.

  15. Structural and electronic properties of carbon nanotubes under hydrostatic pressures

    Institute of Scientific and Technical Information of China (English)

    Zhang Ying; Cao Jue-Xian; Yang Wei

    2008-01-01

    We studied the structural and electronic properties of carbon nanotubes under hydrostatic pressures based on molecular dynamics simulations and first principles band structure calculations.It is found that carbon nanotubes experience a hard-to-soft transition as external pressure increases.The bulk modulus of soft phase is two orders of magnitude smaller than that of hard phase.The band structure calculations show that band gap of (10,0) nanotube increases with the increase of pressure at low pressures. Above a critical pressure (5.70GPa),band gap of (10,0) nanotube drops rapidly and becomes zero at 6.62GPa. Moreover,the calculated charge density shows that a large pressure can induce an sp2-to-sp3 bonding transition,which is confirmed by recent experiments on deformed carbon nanotubes.

  16. Porcine radial artery decellularization by high hydrostatic pressure.

    Science.gov (United States)

    Negishi, Jun; Funamoto, Seiichi; Kimura, Tsuyoshi; Nam, Kwangoo; Higami, Tetsuya; Kishida, Akio

    2015-11-01

    Many types of decellularized tissues have been studied and some have been commercially used in clinics. In this study, small-diameter vascular grafts were made using HHP to decellularize porcine radial arteries. One decellularization method, high hydrostatic pressure (HHP), has been used to prepare the decellularized porcine tissues. Low-temperature treatment was effective in preserving collagen and collagen structures in decellularized porcine carotid arteries. The collagen and elastin structures and mechanical properties of HHP-decellularized radial arteries were similar to those of untreated radial arteries. Xenogeneic transplantation (into rats) was performed using HHP-decellularized radial arteries and an untreated porcine radial artery. Two weeks after transplantation into rat carotid arteries, the HHP-decellularized radial arteries were patent and without thrombosis. In addition, the luminal surface of each decellularized artery was covered by recipient endothelial cells and the arterial medium was fully infiltrated with recipient cells.

  17. On the Nature of Hydrostatic Equilibrium in Galaxy Clusters

    Science.gov (United States)

    Biffi, V.; Borgani, S.; Murante, G.; Rasia, E.; Planelles, S.; Granato, G. L.; Ragone-Figueroa, C.; Beck, A. M.; Gaspari, M.; Dolag, K.

    2016-08-01

    In this paper, we investigate the level of hydrostatic equilibrium (HE) in the intracluster medium of simulated galaxy clusters, extracted from state-of-the-art cosmological hydrodynamical simulations performed with the Smoothed-Particle-Hydrodynamic code GADGET-3. These simulations include several physical processes, among which are stellar and active galactic nucleus feedback, and have been performed with an improved version of the code that allows for a better description of hydrodynamical instabilities and gas mixing processes. Evaluating the radial balance between the gravitational and hydrodynamical forces via the gas accelerations generated, we effectively examine the level of HE in every object of the sample and its dependence on the radial distance from the center and on the classification of the cluster in terms of either cool-coreness or dynamical state. We find an average deviation of 10%-20% out to the virial radius, with no evident distinction between cool-core and non-cool-core clusters. Instead, we observe a clear separation between regular and disturbed systems, with a more significant deviation from HE for the disturbed objects. The investigation of the bias between the hydrostatic estimate and the total gravitating mass indicates that, on average, this traces the deviation from HE very well, even though individual cases show a more complex picture. Typically, in the radial ranges where mass bias and deviation from HE are substantially different, the gas is characterized by a significant amount of random motions (≳ 30 % ), relative to thermal ones. As a general result, the HE-deviation and mass bias, at a given distance from the cluster center, are not very sensitive to the temperature inhomogeneities in the gas.

  18. Thermal conductivity and compressive strain of foam neoprene insulation under hydrostatic pressure

    Science.gov (United States)

    Bardy, Erik; Mollendorf, Joseph; Pendergast, David

    2005-10-01

    The purpose of this study was to show that the thermal properties of foam neoprene under hydrostatic pressure cannot be predicted by theoretical means, and that uni-axial pressure cannot simulate hydrostatic compression. The thermal conductivity and compressive strain of foam neoprene were measured under hydrostatic pressure. In parallel, uni-axial compressive strain data were collected. The experimental set-up and data were put into perspective with past published studies. It was shown that uni-axial compression yielded strains 20-25% greater than did hydrostatic compression. This suggests the need for direct hydrostatic pressure measurement. For comparison to hydrostatic experimental data, a series of thermal conductivity theories of two phase composites based on particulate phase geometry were utilized. Due to their dependence on the porosity and constituent thermal conductivities, a model to predict porosity under hydrostatic pressure was used and an empirical correlation was derived to calculate the thermal conductivity of pure neoprene rubber from experimental data. It was shown that, although some agreement between experimental data and thermal conductivity theories was present, no particular theory can be used because they all fail to model the complex structure of the pores. It was therefore concluded that an experimental programme, such as reported here, is necessary for direct measurement.

  19. The effect of structural coefficient on stiffness and deformation of hydrostatic guideway

    Science.gov (United States)

    Lai, Zhifeng; Qiao, Zheng; Zhang, Peng; Wang, Bo; Wu, Yangong

    2016-10-01

    Hydrostatic guideway has been widely used for ultra-precision machine tools due to its high stiffness and motion accuracy. In order to optimize the stiffness and motion accuracy of hydrostatic guideway, the effect of different diameters orifice restrictors on the stiffness and deformation of hydrostatic guideway is investigated in detail in this paper. The theoretically optimal structural coefficient is verified through the experiments. Hydrostatic guideway can obtain the maximum stiffness when the value of optimal structural coefficient is 0.707. And changing the diameter of orifice restrictors is an effective method to adjusting the structural coefficient. Due to the error caused by manufacture and assembly of hydrostatic guideway, the optimal structural coefficient is hard to be obtained accurately. Based on this condition, a larger structural coefficient is adopted to reduce the oil pressure in the pocket of hydrostatic guideway effectively, so that the deformation of guideway can be reduced. And finally, the stiffness loss caused by the deformation decreased. In addition, the experimental results show that the maximum deformation of hydrostatic guideway can be reduced from 2.06μm to 1.82μm and the stiffness arise from 1453N/μm to 1855N/μm when orifice restrictors with 0.15mm diameter are used rather than 0.2mm diameter.

  20. Application of the MATLAB - Simulink package in the simulation tests on hydrostatic systems

    Directory of Open Access Journals (Sweden)

    Stojek Jerzy

    1998-03-01

    Full Text Available The article shows some selected problems related to both modelling and the simula-tion of hydrostatic systems, by making use of MATLAB-Simulink package. In this purpose there have been considered the basic mathematical models of certain selected elements and pheno-mena occurring in hydrostatic systems. The models are shown as block diagrams adapted to the package requirements. Afterwards, taking as example a complex hydraulic system - that is a hydrostatic transmission - there has been illustrated the use of the models and elementary dia-grams in simulation tests.

  1. Microbiological, physicochemical and sensory parameters of dry fermented sausages manufactured with high hydrostatic pressure processed raw meat.

    Science.gov (United States)

    Omer, M K; Prieto, B; Rendueles, E; Alvarez-Ordoñez, A; Lunde, K; Alvseike, O; Prieto, M

    2015-10-01

    The aim of this trial was to describe physicochemical, microbiological and organoleptic characteristics of dry fermented sausages produced from high hydrostatic pressure (HHP) pre-processed trimmings. During ripening of the meat products pH, weight, water activity (aw), and several microbiological parameters were measured at zero, eight, fifteen days and after 6weeks. Sensory characteristics were estimated at day 15 and after six weeks by a test panel by using several sensory tests. Enterobacteriaceae were not detected in sausages from HHP-processed trimmings. Fermentation was little affected, but weight and aw of the HHP-processed sausages decreased faster during ripening. HHP-treated sausages were consistently less favoured than non HHP-treated sausages, but the strategy may be an alternative approach if the process is optimized.

  2. Mathematical Model and Analysis of the Water-Lubricated Hydrostatic Journal Bearings considering the Translational and Tilting Motions

    Directory of Open Access Journals (Sweden)

    Hui-Hui Feng

    2014-01-01

    Full Text Available The water-lubricated bearings have been paid attention for their advantages to reduce the power loss and temperature rise and increase load capacity at high speed. To fully study the complete dynamic coefficients of two water-lubricated, hydrostatic journal bearings used to support a rigid rotor, a four-degree-of-freedom model considering the translational and tilting motion is presented. The effects of tilting ratio, rotary speed, and eccentricity ratio on the static and dynamic performances of the bearings are investigated. The bulk turbulent Reynolds equation is adopted. The finite difference method and a linear perturbation method are used to calculate the zeroth- and first-order pressure fields to obtain the static and dynamic coefficients. The results suggest that when the tilting ratio is smaller than 0.4 or the eccentricity ratio is smaller than 0.1, the static and dynamic characteristics are relatively insensitive to the tilting and eccentricity ratios; however, for larger tilting or eccentricity ratios, the tilting and eccentric effects should be fully considered. Meanwhile, the rotary speed significantly affects the performance of the hydrostatic, water-lubricated bearings.

  3. Intraband optical absorption in a single quantum ring: Hydrostatic pressure and intense laser field effects

    Science.gov (United States)

    Barseghyan, M. G.

    2016-11-01

    The intraband optical absorption in GaAs/Ga0.7Al0.3As two-dimensional single quantum ring is investigated. Considering the combined effects of hydrostatic pressure and intense laser field the energy of the ground and few excited states has been found using the effective mass approximation and exact diagonalization technique. The energies of these states and the corresponding threshold energy of the intraband optical transitions are examined as a function of hydrostatic pressure for the different values of the laser field parameter. We also investigated the dependencies of the intraband optical absorption coefficient as a function of incident photon energy for different values of hydrostatic pressure and laser field parameter. It is found that the effects of hydrostatic pressure and intense laser field lead to redshift and blueshift of the intraband optical spectrum respectively.

  4. Influence of the Lubricant Thermo-Piezo-Viscous Property on Hydrostatic Bearings in Oil Hydraulics

    DEFF Research Database (Denmark)

    Johansen, Per; Roemer, Daniel Beck; Andersen, Torben O.

    2016-01-01

    In fluid power machinery hydrostatic bearings are frequently used, and a first approximation approach to design is determination of a balance ratio by analytical calculations of the hydrostatic presure force. Usually this is performed assuming that the thermo-piezo-viscous property can be neglected....... However, in applications as piston machines, where pressure in many cases exceeds 200 Bar, such assumption leads to considerable error in the valance ratio prediction, due to the piezo-viscous property of the lubricant. Furthermore, the thermo-viscosity relation also has a significant influence, which...... adds to the discrepancy of such simple design approach. In this paper the hydrostatic pressure force calculation is reviewed in terms of thermohydrodynamic (THD) lubrication theory, and simple analytical approximations of the hydrostatic pressure force, incorporating the piezo-viscous and thermo...

  5. Mass modeling of galaxy clusters: quantifying hydrostatic bias and contribution from non-thermal pressure

    CERN Document Server

    Martizzi, Davide

    2016-01-01

    Galaxy cluster mass determinations achieved using X-ray and Sunyaev-Zeldovich data combined with the assumption of hydrostatic equilibrium are generally biased. The bias exists for two main reasons: non-thermal pressure forces are expected to contribute to the overall pressure balance and deviations from spherical symmetry and hydrostatic equilibrium can be present. In this paper, we use a sample of zoom-in hydrodynamical simulations of galaxy clusters to measure the magnitude of hydrostatic bias and the contribution from turbulence to the total pressure. We propose a new empirical model for turbulent pressure based on our simulations that can be applied to observations. We show that our model can be successfully applied to remove most of the bias related to neglection of turbulent pressure, which is usually not included in hydrostatic cluster mass profile reconstructions. The use of this model may significantly improve the calibration of cluster scaling relations that are a key tool for cluster cosmology.

  6. An efficient non hydrostatic dynamical care far high-resolution simulations down to the urban scale

    Energy Technology Data Exchange (ETDEWEB)

    Bonaventura, L. [MOX-Politecnico, Milano (Italy); Cesari, D. [ARPA, Bologna (Italy). Servizio Idro Meteo

    2005-03-15

    Numerical simulations of idealized stratified flows aver obstacles at different spatial scales demonstrate the very general applicability and the parallel efficiency of a new non hydrostatic dynamical care far simulation of mesoscale flows aver complex terrain.

  7. Sex Conversion Induced by Hydrostatic Pressure in the Marine Copepod Tigriopus californicus.

    Science.gov (United States)

    Vacquier, V D; Belser, W L

    1965-12-17

    High hydrostatic pressure applied to the naupliar larval stages of the marine copepod Tigriopus californicus converts some individuals that would have become males into females. The copepodid stages are not sensitive to pressureinduced conversion.

  8. FO hydrophone with hydrostatic pressure compensation: comparative experiment with a conventional piezo hydrophone

    NARCIS (Netherlands)

    Cheng, L.K.; Bruijn, D. de

    1998-01-01

    This paper presents the performance of a TPD FO hydrophone with hydrostatic pressure compensation. In particularly a comparison with a conventional piezo hydrophone system is discussed. ©2003 Copyright SPIE

  9. The Effect of High Hydrostatic Pressure on Microorganisms in Food Preservation

    Directory of Open Access Journals (Sweden)

    M. Arici

    2006-01-01

    Full Text Available High hydrostatic pressure is a new food preservation technology known for its capacity to inactivate spoilage and pathogenic microorganisms. High-pressure treatments are receiving a great deal of attention for the inactivation of microorganisms in food processing, pressure instead of temperature is used as stabilizing factor. High hydrostatic pressure treatment is the most studied alternative process, many works reported successful results in inactivating a wide range of microorganisms under different operative conditions such as temperature, pressure, exposure time.

  10. Hydrostatic pressure and strain effects in short period InN/GaN superlattices

    DEFF Research Database (Denmark)

    Gorczyca, I.; Suski, T.; Christensen, Niels Egede;

    2012-01-01

    The electronic structures of short-period pseudomorphically grown superlattices (SLs) of the form mInN/nGaN are calculated and the band gap variation with the well and the barrier thicknesses is discussed including hydrostatic pressure effects. The calculated band gap shows a strong dependence on...... strongly on the strain conditions and SL geometry, but weakly on the applied external hydrostatic pressure....

  11. Effects of high hydrostatic pressure on structure and colour of red ginseng (Panax ginseng).

    Science.gov (United States)

    Ghafoor, Kashif; Kim, Sun-Ok; Lee, Dong-Un; Seong, Kijun; Park, Jiyong

    2012-12-01

    The conventional method of processing ginseng (Panax ginseng) roots into red ginseng involves mainly heating and drying processes. In the present study, this method was modified by using high hydrostatic pressure (HHP) to improve the physicochemical characteristics of red ginseng. The HHP process (600 MPa for 1 min) significantly improved the histological properties of red ginseng by increasing cellular disruption and release of cell contents. The total reducing sugar content was significantly (P red ginseng processed at 600 MPa for 1 min. Similarly, the total free amino acid content also increased significantly (from 2.81 to 7.77 mg g(-1)). The HHP process resulted in superior and more even colouration and gave an attractive visual appearance to red ginseng. The optical density at 420 nm and Hunter's colour a value (redness) of extracts prepared from red ginseng increased significantly (P red ginseng has significantly higher reducing sugar and free amino acid contents together with a more compact cell structure and superior visual quality (brighter red colour). Hence the application of HHP in red ginseng processing can result in ginseng products of improved quality compared with those obtained by the conventional method. Copyright © 2012 Society of Chemical Industry.

  12. High hydrostatic pressure specifically affects molecular dynamics and shape of low-density lipoprotein particles

    Science.gov (United States)

    Golub, M.; Lehofer, B.; Martinez, N.; Ollivier, J.; Kohlbrecher, J.; Prassl, R.; Peters, J.

    2017-04-01

    Lipid composition of human low-density lipoprotein (LDL) and its physicochemical characteristics are relevant for proper functioning of lipid transport in the blood circulation. To explore dynamical and structural features of LDL particles with either a normal or a triglyceride-rich lipid composition we combined coherent and incoherent neutron scattering methods. The investigations were carried out under high hydrostatic pressure (HHP), which is a versatile tool to study the physicochemical behavior of biomolecules in solution at a molecular level. Within both neutron techniques we applied HHP to probe the shape and degree of freedom of the possible motions (within the time windows of 15 and 100 ps) and consequently the flexibility of LDL particles. We found that HHP does not change the types of motion in LDL, but influences the portion of motions participating. Contrary to our assumption that lipoprotein particles, like membranes, are highly sensitive to pressure we determined that LDL copes surprisingly well with high pressure conditions, although the lipid composition, particularly the triglyceride content of the particles, impacts the molecular dynamics and shape arrangement of LDL under pressure.

  13. Nonthermal Pasteurization of Fermented Green Table Olives by means of High Hydrostatic Pressure Processing

    Directory of Open Access Journals (Sweden)

    Anthoula A. Argyri

    2014-01-01

    Full Text Available Green fermented olives cv. Halkidiki were subjected to different treatments of high hydrostatic pressure (HHP processing (400, 450, and 500 MPa for 15 or 30 min. Total viable counts, lactic acid bacteria and yeasts/moulds, and the physicochemical characteristics of the product (pH, colour, and firmness were monitored right after the treatment and after 7 days of storage at 20°C to allow for recovery of injured cells. The treatments at 400 MPa for 15 and 30 min, 450 MPa for 15 and 30 min, and 500 MPa for 15 min were found insufficient as a recovery of the microbiota was observed. The treatment at 500 MPa for 30 min was effective in reducing the olive microbiota below the detection limit of the enumeration method after the treatment and after 1 week of storage and was chosen as being more appropriate for storing olives for an extended time period (5 months. After 5 months of storage at 20°C, no microbiota was detected in treated samples, while significant changes for both HHP treated and untreated olives were observed for colour parameters only (minor degradation. In conclusion, HHP treatment may introduce a reliable nonthermal pasteurization method to extend the microbiological shelf-life of fermented table olives.

  14. Using changes in hydrostatic and osmotic pressure to manipulate metabolic function in chondrocytes.

    Science.gov (United States)

    Mizuno, Shuichi; Ogawa, Rei

    2011-06-01

    Articular cartilage has distinct histological depth zones. In each zone, chondrocytes are subject to different hydrostatic (HP) and osmotic pressure (OP) due to weight-bearing and joint-loading. Previous in vitro studies of regeneration and pathophysiology in cartilage have failed to consider the characteristics of histological heterogeneity and the effects of combinations of changes in HP and OP. Thus, we have constructed molecular, biochemical, and histological profiles of anabolic and catabolic molecules produced by chondrocytes from each depth zone isolated from bovine articular cartilage in response to changes in HP and OP. We cultured the chondrocytes with combinations of loading or off-loading of HP at 0-0.5 MPa, 0.5 Hz, and changes in OP of 300-450 mosM over 1 wk, and evaluated mRNA expression and immunohistology of both anabolic and catabolic molecules and amounts of accumulated sulfated glycosaminoglycan. Any changes in HP and OP upregulated mRNA of anabolic and catabolic molecules in surface-, middle-, and deep-zone cells, in descending order of magnitude. Off-loading HP maintained the anabolic and reduced the catabolic mRNA; high OP retained upregulation of catabolic mRNA. These molecular profiles were consistent with immunohistological and biochemical findings. Changes in HP and OP are essential for simulating chondrocyte physiology and useful for manipulating phenotypes.

  15. ELEMENT DESIGN FOR AN INKJET SYSTEM OF HYDROSTATIC GAS BEARING CONTROL

    Directory of Open Access Journals (Sweden)

    T. E. Il'ina

    2015-09-01

    Full Text Available Subject of Study. The paper discusses the concept of inkjet systems application, also known as pneumonics, for automatic hydrostatic gas bearing control. Inkjet systems have the advantages over traditional control systems in those problems where the speed of traditional mechanical, electrical or hydraulic servomotors is not enough. Control of the shaft position in gas bearing with forced gas supply into the gap between the shaft and the bearing is typical for this class of problems. In this case, control means the pressure changing or flow rate of gas supplied to the gap by at least one of three axes at a frequency higher than the nominal speed of the shaft. Thus, high speed of response is required from the system. The objective of this work is to design a discrete jet element, testing of its geometry and switching characteristics. Main Results. The discrete inkjet element for oil-free non-contact transmission working on the refrigerant was designed. Relay transition process was modeled in the inkjet element with the use of numerical methods. The switching time has reached 0.2-0.3 ms; this is one order less than the requirements of aircraft control systems, which typically operate at a frequency of about 200 Hz. It is shown that periodic oscillations with high frequency occur when the control signal is injected with insufficient level of pressure. Therefore, a separate design task is to determine the minimum pressure allowable in the control channel.

  16. 大型数控落地镗铣床滑枕静压导轨的分析与研究%Analysis and Research of Ram Hydrostatic Guideway for Large NC Floor Type Boring and Milling Machine

    Institute of Scientific and Technical Information of China (English)

    华小龙; 郭旭红; 潘贤兵

    2014-01-01

    分析了大型落地镗铣床使用静压导轨的原因,介绍了静压导轨的分类和特点,并对滑枕静压导轨的参数进行了计算。通过在大型落地镗铣床上应用静压导轨技术,使得大型落地镗铣床的动态特性好、抗振性强、运动精度高,大大提高了工件的加工精度。%The cause of using hydrostatic guideway in large floor type boring and milling machine was analyzed.The classifica-tion and characteristics of hydrostatic guideway were introduced,and also the parameters of ram hydrostatic guideway were calculated. Through the application of technology of hydrostatic guideway in large floor type boring and milling machine,the dynamic characteris-tics of the machine was good,and it also had the strong vibration resistance and high motion precision.The processing precision of the workpiece is improved greatly.

  17. Challenging Oil Bioremediation at Deep-Sea Hydrostatic Pressure

    Science.gov (United States)

    Scoma, Alberto; Yakimov, Michail M.; Boon, Nico

    2016-01-01

    The Deepwater Horizon accident has brought oil contamination of deep-sea environments to worldwide attention. The risk for new deep-sea spills is not expected to decrease in the future, as political pressure mounts to access deep-water fossil reserves, and poorly tested technologies are used to access oil. This also applies to the response to oil-contamination events, with bioremediation the only (bio)technology presently available to combat deep-sea spills. Many questions about the fate of petroleum-hydrocarbons within deep-sea environments remain unanswered, as well as the main constraints limiting bioremediation under increased hydrostatic pressures and low temperatures. The microbial pathways fueling oil bioassimilation are unclear, and the mild upregulation observed for beta-oxidation-related genes in both water and sediments contrasts with the high amount of alkanes present in the spilled oil. The fate of solid alkanes (tar), hydrocarbon degradation rates and the reason why the most predominant hydrocarbonoclastic genera were not enriched at deep-sea despite being present at hydrocarbon seeps at the Gulf of Mexico have been largely overlooked. This mini-review aims at highlighting the missing information in the field, proposing a holistic approach where in situ and ex situ studies are integrated to reveal the principal mechanisms accounting for deep-sea oil bioremediation. PMID:27536290

  18. Quantitative assessment of meteorological and tropospheric Zenith Hydrostatic Delay models

    Science.gov (United States)

    Zhang, Di; Guo, Jiming; Chen, Ming; Shi, Junbo; Zhou, Lv

    2016-09-01

    Tropospheric delay has always been an important issue in GNSS/DORIS/VLBI/InSAR processing. Most commonly used empirical models for the determination of tropospheric Zenith Hydrostatic Delay (ZHD), including three meteorological models and two empirical ZHD models, are carefully analyzed in this paper. Meteorological models refer to UNB3m, GPT2 and GPT2w, while ZHD models include Hopfield and Saastamoinen. By reference to in-situ meteorological measurements and ray-traced ZHD values of 91 globally distributed radiosonde sites, over a four-years period from 2010 to 2013, it is found that there is strong correlation between errors of model-derived values and latitudes. Specifically, the Saastamoinen model shows a systematic error of about -3 mm. Therefore a modified Saastamoinen model is developed based on the "best average" refractivity constant, and is validated by radiosonde data. Among different models, the GPT2w and the modified Saastamoinen model perform the best. ZHD values derived from their combination have a mean bias of -0.1 mm and a mean RMS of 13.9 mm. Limitations of the present models are discussed and suggestions for further improvements are given.

  19. Challenging oil bioremediation at deep-sea hydrostatic pressure

    Directory of Open Access Journals (Sweden)

    Alberto Scoma

    2016-08-01

    Full Text Available The Deepwater Horizon (DWH accident has brought oil contamination of deep-sea environments to worldwide attention. The risk for new deep-sea spills is not expected to decrease in the future, as political pressure mounts to access deep-water fossil reserves, and poorly tested technologies are used to access oil. This also applies to the response to oil-contamination events, with bioremediation the only (biotechnology presently available to combat deep-sea spills. Many questions about the fate of petroleum-hydrocarbons at deep-sea remain unanswered, as much as the main constraints limiting bioremediation under increased hydrostatic pressures and low temperatures. The microbial pathways fueling oil take up are unclear, and the mild upregulation observed for beta-oxidation-related genes in both water and sediments contrasts with the high amount of alkanes present in the spilled-oil. The fate of solid alkanes (tar and that of hydrocarbons degradation rates was largely overlooked, as the reason why the most predominant hydrocarbonoclastic genera were not enriched at deep-sea, despite being present at hydrocarbon seeps at the Gulf of Mexico. This mini-review aims at highlighting the missing information in the field, proposing a holistic approach where in situ and ex situ studies are integrated to reveal the principal mechanisms accounting for deep-sea oil bioremediation.

  20. II-VI wide band gap semiconductors under hydrostatic pressure

    Science.gov (United States)

    Baquero, R.; Decoss, R.; Olguin, D.

    1993-08-01

    We set an analytical expression for the gap as a function of hydrostatic deformation, E(sub g)(epsilon), by diagonalizing in Gamma the corresponding empirical tight-binding Hamiltonian (ETBH). In the ETBH we use the well known d(exp -2) Harrison scaling law (HSL) to adjust the TB parameter (TBP) to the changes in interatomic distances. We do not consider cation-anion charge transfer. We calculate E(sub g)(epsilon) for wide band gap II-VI semiconductors with zincblende crystal structure for deformations under pressure up to -5 percent. Results are in good agreement with experiment for the compounds of lower ionicity but deviate as the ionicity of the compound increases. This is due to the neglect of charge transfer which should be included self-consistently. Within the approximation we always find a positive second derivative of E(sub g)(epsilon) with respect to epsilon, independent of the material. Furthermore, the inclusion of deviations from HSL appear to be unimportant to this problem.

  1. Magnetoresistance in CePtSn under high hydrostatic pressures

    Energy Technology Data Exchange (ETDEWEB)

    Misek, M. [Charles University, Faculty of Mathematics and Physics, Department of Condensed Matter Physics, Ke Karlovu 5, 121 16 Prague (Czech Republic)], E-mail: martinmisek@hotmail.com; Prokleska, J.; Javorsky, P.; Sechovsky, V. [Charles University, Faculty of Mathematics and Physics, Department of Condensed Matter Physics, Ke Karlovu 5, 121 16 Prague (Czech Republic)

    2009-07-01

    We report the evolution of magnetic-history dependent antiferromagnetic phases in CePtSn. We concentrate on the magnetoresistance in magnetic fields up to 14 T applied along the crystallographic b-axis, measured on a CePtSn single crystal subjected to hydrostatic pressure (p {<=} 2.2 GPa) generated in a double-layered CuBe/NiCrAl piston cylinder cell. We observe a gradual increase of the critical field B{sub c}{sup LF} of the low field (LF) transition up to {approx}1.2 GPa where only one transition is observed at {approx}11.5 T. For pressures above 1.2 GPa we observe two transitions again and B{sub c}{sup LF} decreases with further increasing pressure to reach B{sub c}{sup LF}{approx}7.5T at 2.5 GPa. The position of the high field (HF) transition remains almost unaffected by applied pressure. A scenario considering the spin-slip AF structure in CePtSn is briefly discussed.

  2. Challenging Oil Bioremediation at Deep-Sea Hydrostatic Pressure.

    Science.gov (United States)

    Scoma, Alberto; Yakimov, Michail M; Boon, Nico

    2016-01-01

    The Deepwater Horizon accident has brought oil contamination of deep-sea environments to worldwide attention. The risk for new deep-sea spills is not expected to decrease in the future, as political pressure mounts to access deep-water fossil reserves, and poorly tested technologies are used to access oil. This also applies to the response to oil-contamination events, with bioremediation the only (bio)technology presently available to combat deep-sea spills. Many questions about the fate of petroleum-hydrocarbons within deep-sea environments remain unanswered, as well as the main constraints limiting bioremediation under increased hydrostatic pressures and low temperatures. The microbial pathways fueling oil bioassimilation are unclear, and the mild upregulation observed for beta-oxidation-related genes in both water and sediments contrasts with the high amount of alkanes present in the spilled oil. The fate of solid alkanes (tar), hydrocarbon degradation rates and the reason why the most predominant hydrocarbonoclastic genera were not enriched at deep-sea despite being present at hydrocarbon seeps at the Gulf of Mexico have been largely overlooked. This mini-review aims at highlighting the missing information in the field, proposing a holistic approach where in situ and ex situ studies are integrated to reveal the principal mechanisms accounting for deep-sea oil bioremediation.

  3. Non-hydrostatic general circulation model of the Venus atmosphere

    Science.gov (United States)

    Rodin, Alexander V.; Mingalev, Igor; Orlov, Konstantin; Ignatiev, Nikolay

    We present the first non-hydrostatic global circulation model of the Venus atmosphere based on the complete set of gas dynamics equations. The model employs a spatially uniform triangular mesh that allows to avoid artificial damping of the dynamical processes in the polar regions, with altitude as a vertical coordinate. Energy conversion from the solar flux into atmospheric motion is described via explicitly specified heating and cooling rates or, alternatively, with help of the radiation block based on comprehensive treatment of the Venus atmosphere spectroscopy, including line mixing effects in CO2 far wing absorption. Momentum equations are integrated using the semi-Lagrangian explicit scheme that provides high accuracy of mass and energy conservation. Due to high vertical grid resolution required by gas dynamics calculations, the model is integrated on the short time step less than one second. The model reliably repro-duces zonal superrotation, smoothly extending far below the cloud layer, tidal patterns at the cloud level and above, and non-rotating, sun-synchronous global convective cell in the upper atmosphere. One of the most interesting features of the model is the development of the polar vortices resembling those observed by Venus Express' VIRTIS instrument. Initial analysis of the simulation results confirms the hypothesis that it is thermal tides that provides main driver for the superrotation.

  4. On the nature of hydrostatic equilibrium in galaxy clusters

    CERN Document Server

    Biffi, V; Murante, G; Rasia, E; Planelles, S; Granato, G L; Ragone-Figueroa, C; Beck, A M; Gaspari, M; Dolag, K

    2016-01-01

    In this paper we investigate the level of hydrostatic equilibrium (HE) in the intra-cluster medium of simulated galaxy clusters, extracted from state-of-the-art cosmological hydrodynamical simulations performed with the Smoothed-Particle-Hydrodynamic code GADGET-3. These simulations include several physical processes, among which stellar and AGN feedback, and have been performed with an improved version of the code that allows for a better description of hydrodynamical instabilities and gas mixing processes. Evaluating the radial balance between the gravitational and hydrodynamical forces, via the gas accelerations generated, we effectively examine the level of HE in every object of the sample, its dependence on the radial distance from the center and on the classification of the cluster in terms of either cool-coreness or dynamical state. We find an average deviation of 10-20% out to the virial radius, with no evident distinction between cool-core and non-cool-core clusters. Instead, we observe a clear separ...

  5. Day-night variations in malate concentration, osmotic pressure, and hydrostatic pressure in Cereus validus

    Energy Technology Data Exchange (ETDEWEB)

    Luettge, U.; Nobel, P.S.

    1984-07-01

    Malate concentration and stem osmotic pressure concomitantly increase during nighttime CO/sub 2/ fixation and then decrease during the daytime in the obligate Crassulacean acid metabolism (CAM) plant, Cereus validus (Cactaceae). Changes in malate osmotic pressure calculated using the Van't Hoff relation match the changes in stem osmotic pressure, indicating that changes in malate level affected the water relations of the succulent stems. In contrast to stem osmotic pressure, stem water potential showed little day-night changes, suggesting that changes in cellular hydrostatic pressure occurred. This was corroborated by direct measurements of hydrostatic pressure using the Juelich pressure probe where a small oil-filled micropipette is inserted directly into chlorenchyma cells, which indicated a 4-fold increase in hydrostatic pressure from dusk to dawn. A transient increase of hydrostatic pressure at the beginning of the dark period was correlated with a short period of stomatal closing between afternoon and nighttime CO/sub 2/ fixation, suggesting that the rather complex hydrostatic pressure patterns could be explained by an interplay between the effects of transpiration and malate levels. A second CAM plant, Agave deserti, showed similar day-night changes in hydrostatic pressure in its succulent leaves. It is concluded that, in addition to the inverted stomatal rhythm, the oscillations of malate markedly affect osmotic pressures and hence water relations of CAM plants. 13 references, 4 figures.

  6. A Semi-Hydrostatic Theory of Gravity-Dominated Compressible Flow

    Science.gov (United States)

    Dubos, T.; Voitus, F.

    2014-12-01

    Compressible Euler equations support the propagation of acoustic waves. Although much progress has been achieved towards efficient and accurate solutions to the resulting numerical difficulties, it can still be desirable to identify "unified" equations of motion that would not support acoustic waves while retaining accuracy at large and small scales. Even if such equations are eventually not chosen as the basis of a numerical model, they may help identifying the independent degrees of freedom of the atmospheric flow to be modeled and how the dependent fields are related to the independent fields. From Hamilton's least action principle (HP), "semi-hydrostatic" compressible equations of motion with density diagnosed from potential temperature through hydrostatic balance are derived. Energy, potential vorticity and momentum are conserved. Slaving density to potential temperature suppresses the degrees of freedom supporting the propagation of acoustic waves and results in a sound-proof system. Scale analysis and linear normal modes analysis for an isothermal state of rest suggest that the semy-hydrostatic system is accurate from hydrostatic to non-hydrostatic scales, except for deep internal gravity waves (Figure : decimal logarithm of relative error of the frequency of internal normal modes of a non-rotating isothermal atmosphere as a function of horizontal and vertical wavenumbers k,m normalized by the scale height H). Especially the Lamb wave and long Rossby waves are not distorted, unlike with anelastic or pseudo-incompressible systems. Compared to similar equations derived by Arakawa and Konor (2009), the semi-hydrostatic system possesses an additional term in the horizontal momentum budget. This term is an apparent force resulting from the vertical coordinate not being the actual height of an air parcel, but its hydrostatic height, i.e. the hypothetical height it would have after the atmospheric column it belongs to has reached hydrostatic balance through

  7. Effects of high hydrostatic pressures on living cells: a consequence of the properties of macromolecules and macromolecule-associated water.

    Science.gov (United States)

    Mentré, P; Hui Bon Hoa, G

    2001-01-01

    Sixty percent of the Earth's biomass is found in the sea, at depths greater than 1000 m, i.e., at hydrostatic pressures higher than 100 atm. Still more surprising is the fact that living cells can reversibly withstand pressure shifts of 1000 atm. One explanation lies in the properties of cellular water. Water forms a very thin film around macromolecules, with a heterogeneous structure that is an image of the heterogeneity of the macromolecular surface. The density of water in contact with macromolecules reflects the physical properties of their different domains. Therefore, any macromolecular shape variations involving the reorganization of water and concomitant density changes are sensitive to pressure (Le Chatelier's principle). Most of the pressure-induced changes to macromolecules are reversible up to 2000 atm. Both the effects of pressure shifts on living cells and the characteristics of pressure-adapted species are opening new perspectives on fundamental problems such as regulation and adaptation.

  8. Hydrostatic self-locking bevel differential gear; Hydrostatisch selbstsperrendes Kegelraddifferentialgetriebe

    Energy Technology Data Exchange (ETDEWEB)

    Kalmbach, K.

    2001-07-01

    The product range of the rail vehicle industry comprises the construction of railroad material for long-distance and short-distance transport. This includes, for example, locomotives and cars, subway, light railway and tramway cars as well as rail vehicle equipment. The development of the industry is determined by the demand for transport services and government actions for the extension of railways and procurement of suitable vehicle types. In contrast to road vehicles, differential gears are only used in a negligible percentage of rail vehicles. Primarily in the short-distance rail transport sector, the demand for differential gears is growing due to increased drive power, smaller wheel diameters, lower vehicle mass with higher load capacity, the introduction of low-floor technology as well as the requirement of employing ever more quiet vehicles. In hydrostatic self-locking differential gears, oil is supplied to the gears within the differential gearbox. They only rotate relative to each other when the differential gear performs a compensation movement. In this case, oil is transported in the tooth space to the meshing of the gears, where it is displaced due to the meshing and must drain through tight gaps. The pressure generated by this process acts against the compensation movement of the gear, and the drive torque is transmitted to the wheel that has the higher friction. The achievable locking torque is linearly dependent on the differential speed of the drive wheel. This locking effect is achieved without wear-prone components and works automatically without active external intervention. The design space required corresponds to that of conventional differential gears, as the locking effect is integrated in the existing design. (orig.)

  9. Hydrostatic self-locking bevel differential gear; Hydrostatisch selbstsperrendes Kegelraddifferentialgetriebe

    Energy Technology Data Exchange (ETDEWEB)

    Kalmbach, K.

    2001-07-01

    The product range of the rail vehicle industry comprises the construction of railroad material for long-distance and short-distance transport. This includes, for example, locomotives and cars, subway, light railway and tramway cars as well as rail vehicle equipment. The development of the industry is determined by the demand for transport services and government actions for the extension of railways and procurement of suitable vehicle types. In contrast to road vehicles, differential gears are only used in a negligible percentage of rail vehicles. Primarily in the short-distance rail transport sector, the demand for differential gears is growing due to increased drive power, smaller wheel diameters, lower vehicle mass with higher load capacity, the introduction of low-floor technology as well as the requirement of employing ever more quiet vehicles. In hydrostatic self-locking differential gears, oil is supplied to the gears within the differential gearbox. They only rotate relative to each other when the differential gear performs a compensation movement. In this case, oil is transported in the tooth space to the meshing of the gears, where it is displaced due to the meshing and must drain through tight gaps. The pressure generated by this process acts against the compensation movement of the gear, and the drive torque is transmitted to the wheel that has the higher friction. The achievable locking torque is linearly dependent on the differential speed of the drive wheel. This locking effect is achieved without wear-prone components and works automatically without active external intervention. The design space required corresponds to that of conventional differential gears, as the locking effect is integrated in the existing design. (orig.)

  10. Lamb's Hydrostatic Adjustment for Heating of Finite Duration.

    Science.gov (United States)

    Sotack, Timothy; Bannon, Peter R.

    1999-01-01

    Lamb's hydrostatic adjustment problem for the linear response of an infinite, isothermal atmosphere to an instantaneous heating of infinite horizontal extent is generalized to include the effects of heating of finite duration. Three different time sequences of the heating are considered: a top hat, a sine, and a sine-squared heating. The transient solution indicates that heating of finite duration generates broader but weaker acoustic wave fronts. However, it is shown that the final equilibrium is the same regardless of the heating sequence provided the net heating is the same.A Lagrangian formulation provides a simple interpretation of the adjustment. The heating generates an entropy anomaly that is initially realized completely as a pressure excess with no density perturbation. In the final state the entropy anomaly is realized as a density deficit with no pressure perturbation. Energetically the heating generates both available potential energy and available elastic energy. The former remains in the heated layer while the latter is carried off by the acoustic waves.The wave energy generation is compared for the various heating sequences. In the instantaneous case, 28.6% of the total energy generation is carried off by waves. This fraction is the ratio of the ideal gas constant R to the specific heat at constant pressure cp. For the heatings of finite duration considered, the amount of wave energy decreases monotonically as the heating duration increases and as the heating thickness decreases. The wave energy generation approaches zero when (i) the duration of the heating is comparable to or larger than the acoustic cutoff period, 2/NA 300 s, and (ii) the thickness of the heated layer approaches zero. The maximum wave energy occurs for a thick layer of heating of small duration and is the same as that for the instantaneous case.The effect of a lower boundary is also considered.

  11. Hydrostatic strain enhancement in laterally confined SiGe nanostripes

    Science.gov (United States)

    Vanacore, G. M.; Chaigneau, M.; Barrett, N.; Bollani, M.; Boioli, F.; Salvalaglio, M.; Montalenti, F.; Manini, N.; Caramella, L.; Biagioni, P.; Chrastina, D.; Isella, G.; Renault, O.; Zani, M.; Sordan, R.; Onida, G.; Ossikovski, R.; Drouhin, H.-J.; Tagliaferri, A.

    2013-09-01

    Strain engineering in SiGe nanostructures is fundamental for the design of optoelectronic devices at the nanoscale. Here we explore a new strategy, where SiGe structures are laterally confined by the Si substrate, to obtain high tensile strain yet avoid the use of external stressors, thus improving the scalability. Spectromicroscopy techniques, finite element method simulations, and ab initio calculations are used to investigate the strain state of laterally confined Ge-rich SiGe nanostripes. Strain information is obtained by tip-enhanced Raman spectroscopy with an unprecedented lateral resolution of ˜30 nm. The nanostripes exhibit a large tensile hydrostatic strain component, which is maximal at the center of the top free surface and becomes very small at the edges. The maximum lattice deformation is larger than the typical values of thermally relaxed Ge/Si(001) layers. This strain enhancement originates from a frustrated relaxation in the out-of-plane direction, resulting from the combination of the lateral confinement induced by the substrate side walls and the plastic relaxation of the misfit strain in the (001) plane at the SiGe/Si interface. The effect of this tensile lattice deformation at the stripe surface is probed by work function mapping, which is performed with a spatial resolution better than 100 nm using x-ray photoelectron emission microscopy. The nanostripes exhibit a positive work function shift with respect to a bulk SiGe alloy, quantitatively confirmed by electronic structure calculations of tensile-strained configurations. The present results have a potential impact on the design of optoelectronic devices at a nanometer-length scale.

  12. A non-hydrostatic pressure distribution solver for the nonlinear shallow water equations over irregular topography

    Science.gov (United States)

    Aricò, Costanza; Lo Re, Carlo

    2016-12-01

    We extend a recently proposed 2D depth-integrated Finite Volume solver for the nonlinear shallow water equations with non-hydrostatic pressure distribution. The proposed model is aimed at simulating both nonlinear and dispersive shallow water processes. We split the total pressure into its hydrostatic and dynamic components and solve a hydrostatic problem and a non-hydrostatic problem sequentially, in the framework of a fractional time step procedure. The dispersive properties are achieved by incorporating the non-hydrostatic pressure component in the governing equations. The governing equations are the depth-integrated continuity equation and the depth-integrated momentum equations along the x, y and z directions. Unlike the previous non-hydrostatic shallow water solver, in the z momentum equation, we retain both the vertical local and convective acceleration terms. In the former solver, we keep only the local vertical acceleration term. In this paper, we investigate the effects of these convective terms and the possible improvements of the computed solution when these terms are not neglected in the governing equations, especially in strongly nonlinear processes. The presence of the convective terms in the vertical momentum equation leads to a numerical solution procedure, which is quite different from the one of the previous solver, in both the hydrostatic and dynamic steps. We discretize the spatial domain using unstructured triangular meshes satisfying the Generalized Delaunay property. The numerical solver is shock capturing and easily addresses wetting/drying problems, without any additional equation to solve at wet/dry interfaces. We present several numerical applications for challenging flooding processes encountered in practical aspects over irregular topography, including a new set of experiments carried out at the Hydraulics Laboratory of the University of Palermo.

  13. A randomized trial of pneumatic reduction versus hydrostatic reduction for intussusception in pediatric patients.

    Science.gov (United States)

    Xie, Xiaolong; Wu, Yang; Wang, Qi; Zhao, Yiyang; Chen, Guobin; Xiang, Bo

    2017-08-08

    Data of randomly controlled trials comparing the hydrostatic and pneumatic reduction for intussusception in pediatric patients as initial therapy are lacking. The aim of this study was to conduct a randomly controlled trial to compare the effectiveness and safety of the hydrostatic and pneumatic reduction techniques. All intussusception patients who visited West China Hospital of Sichuan University from January 2014 to December 2015 were enrolled in this study in which they underwent pneumatic reduction or hydrostatic reduction. Patients were randomized into ultrasound-guided hydrostatic or X-ray-guided pneumatic reduction group. The data collected includes demographic data, symptoms, signs, and investigations. The primary outcome of the study was the success rate of reduction. And the secondary outcomes of the study were the rates of intestinal perforations and recurrence. A total of 124 children with intussusception who had met the inclusion criteria were enrolled. The overall success rate of this study was 90.32%. Univariable analysis showed that the success rate of hydrostatic reduction with normal saline (96.77%) was significantly higher than that of pneumatic reduction with air (83.87%) (p=0.015). Perforation after reduction was found in only one of the pneumatic reduction group. The recurrence rate of intussusception in the hydrostatic reduction group was 4.84% compared with 3.23% of pneumatic reduction group. Our study found that ultrasound-guided hydrostatic reduction is a simple, safe and effective nonoperative treatment for pediatric patients suffering from intussusceptions, and should be firstly adopted in the treatment of qualified patients. Therapeutic study TYPE OF STUDY: Prospective study. Copyright © 2017 Elsevier Inc. All rights reserved.

  14. Characteristics of saccharide-protein linkage in the enzymatic hydrolysis of rice protein pretreated with high hydrostatic pressure%高压处理大米蛋白酶解过程中糖-蛋白结合特性的变化

    Institute of Scientific and Technical Information of China (English)

    王章存; 崔胜文; 袁道强; 郑坚强; 安广杰; 赵学伟; 原媛

    2013-01-01

    研究了热变性大米蛋白经100MPa高压处理的酶解过程中蛋白质与糖结合特性的变化,并与未高压处理的酶解物进行了比较.凝胶色谱分析显示,经高压处理的大米蛋白可溶性酶解物中蛋白/糖含量比值低于常压处理者.β-消去反应证明了蛋白和糖的连接方式为N-糖肽键结合.FT-IR分析表明,高压和常压处理后大米蛋白的酶解残余物中均含有糖组分,且高压处理者的糖相对含量较低.SDS-PAGE和PAS-Schiff试剂染色显示,高压和未高压处理者的酶解残余物中14ku均是糖蛋白.上述结果表明,高压处理有利于糖蛋白的酶解,但部分糖蛋白仍呈不溶解状态.%The binding characteristics between protein and saccharide of enzymatic hydrolysates of rice protein pretreated by 100MPa were researched.The results showed that the ratio of protein/saccharide in the soluble hydrolysates pretreated by 100MPa was lower than that of unpretreated.β-elimination reaction showed that protein and saccharide was linked together by N-glycoside peptide bond.FT-IR spectrum proved the insoluble hydrolyzed rice protein was yet glycoprotein.The staining with Coomassie brilliant blue and periodic acid-Schiff (PAS) reaction in SDS-PAGE showed the 14ku subunit of insoluble hydrolyzed rice protein was yet glycoprotein.The results above indicated that high pressure treatment was helpful for the hydrolysis of rice glycoprotein,some of them was yet insoluble in water.

  15. An Experimental Study of Dynamic Tensile Failure of Rocks Subjected to Hydrostatic Confinement

    Science.gov (United States)

    Wu, Bangbiao; Yao, Wei; Xia, Kaiwen

    2016-10-01

    It is critical to understand the dynamic tensile failure of confined rocks in many rock engineering applications, such as underground blasting in mining projects. To simulate the in situ stress state of underground rocks, a modified split Hopkinson pressure bar system is utilized to load Brazilian disc (BD) samples hydrostatically, and then exert dynamic load to the sample by impacting the striker on the incident bar. The pulse shaper technique is used to generate a slowly rising stress wave to facilitate the dynamic force balance in the tests. Five groups of Laurentian granite BD samples (with static BD tensile strength of 12.8 MPa) under the hydrostatic confinement of 0, 5, 10, 15, and 20 MPa were tested with different loading rates. The result shows that the dynamic tensile strength increases with the hydrostatic confining pressure. It is also observed that under the same hydrostatic pressure, the dynamic tensile strength increases with the loading rate, revealing the so-called rate dependency for engineering materials. Furthermore, the increment of the tensile strength decreases with the hydrostatic confinement, which resembles the static tensile behavior of rock under confining pressure, as reported in the literature. The recovered samples are examined using X-ray micro-computed tomography method and the observed crack pattern is consistent with the experimental result.

  16. Hydrostatic pressure effects on the state density and optical transitions in quantum dots

    Energy Technology Data Exchange (ETDEWEB)

    Galindez-Ramirez, G; Perez-Merchancano, S T [Departamento de Fisica, Universidad del Cauca, calle 5 4-70, Popayan (Colombia); Paredes Gutierrez, H [Escuela de Fisica, Universidad Industrial de Santander, A. A. 678, Bucaramanga (Colombia); Gonzalez, J D, E-mail: jdavid0831@gmail.co [Grupo de Investigacion en teorIa de la Materia Condensada, Universidad del Magdalena, A.A. 731, Santa Marta (Colombia)

    2010-09-01

    Using the effective mass approximation and variational method we have computed the effects of hydrostatic pressure on the absorption and photoluminescence spectra in spherical quantum dot GaAs-(Ga, Al) As, considering a finite confinement potential of this particular work we show the optical transitions in quantum of various sizes in the presence of hydrogenic impurities and hydrostatic pressure effects. Our first result describes the spectrum of optical absorption of 500 A QD for different values of hydrostatic pressure P = 0, 20 and 40 Kbar. The absorption peaks are sensitive to the displacement of the impurity center to the edge of the quantum dot and even more when the hydrostatic pressure changes in both cases showing that to the extent that these two effects are stronger quantum dots respond more efficiently. Also this result can be seen in the study of the photoluminescence spectrum as in the case of acceptor impurities consider them more efficiently capture carriers or electrons that pass from the conduction band to the valence band. Density states with randomly distributed impurity show that the additional peaks in the curves of the density of impurity states appear due to the presence of the additional hydrostatic pressure effects.

  17. PPARγ ligands decrease hydrostatic pressure-induced platelet aggregation and proinflammatory activity.

    Directory of Open Access Journals (Sweden)

    Fang Rao

    Full Text Available Hypertension is known to be associated with platelet overactivity, but the direct effects of hydrostatic pressure on platelet function remain unclear. The present study sought to investigate whether elevated hydrostatic pressure is responsible for platelet activation and to address the potential role of peroxisome proliferator-activated receptor-γ (PPARγ. We observed that hypertensive patients had significantly higher platelet volume and rate of ADP-induced platelets aggregation compared to the controls. In vitro, Primary human platelets were cultured under standard (0 mmHg or increased (120, 180, 240 mmHg hydrostatic pressure for 18 h. Exposure to elevated pressure was associated with morphological changes in platelets. Platelet aggregation and PAC-1 (the active confirmation of GPIIb/IIIa binding were increased, CD40L was translocated from cytoplasm to the surface of platelet and soluble CD40L (sCD40L was released into the medium in response to elevated hydrostatic pressure (180 and 240 mmHg. The PPARγ activity was up-regulated as the pressure was increased from 120 mmHg to 180 mmHg. Pressure-induced platelet aggregation, PAC-1 binding, and translocation and release of CD40L were all attenuated by the PPARγ agonist Thiazolidinediones (TZDs. These results demonstrate that platelet activation and aggregation are increased by exposure to elevated pressure and that PPARγ may modulate platelet activation induced by high hydrostatic pressure.

  18. Hydrostatic pressure decreases membrane fluidity and lipid desaturase expression in chondrocyte progenitor cells.

    Science.gov (United States)

    Montagne, Kevin; Uchiyama, Hiroki; Furukawa, Katsuko S; Ushida, Takashi

    2014-01-22

    Membrane biomechanical properties are critical in modulating nutrient and metabolite exchange as well as signal transduction. Biological membranes are predominantly composed of lipids, cholesterol and proteins, and their fluidity is tightly regulated by cholesterol and lipid desaturases. To determine whether such membrane fluidity regulation occurred in mammalian cells under pressure, we investigated the effects of pressure on membrane lipid order of mouse chondrogenic ATDC5 cells and desaturase gene expression. Hydrostatic pressure linearly increased membrane lipid packing and simultaneously repressed lipid desaturase gene expression. We also showed that cholesterol mimicked and cholesterol depletion reversed those effects, suggesting that desaturase gene expression was controlled by the membrane physical state itself. This study demonstrates a new effect of hydrostatic pressure on mammalian cells and may help to identify the molecular mechanisms involved in hydrostatic pressure sensing in chondrocytes.

  19. On variable hydrostatic transmission for road vehicles, powered by supply of fluid at constant pressure

    Science.gov (United States)

    Magi, M.; Freivald, A.; Andersson, I.; Ericsson, U.

    1981-05-01

    Various hydrostatic power transmission systems for automotive applications with power supply at constant pressure and unrestricted flow and with a Volvo Flygmotor variable displacement motor as the principal unit were investigated. Two most promising concepts were analyzed in detail and their main components optimized for minimum power loss at the EPA Urban Driving Cycle. The best fuel consumption is less than 10 lit. per 100 kM for a 1542 kG vehicle with a hydrostatic motor and a two speed gear box in series (braking power not recovered). Realistic system pressure affects the fuel consumption just slightly, but the package volume/weight drastically. Back pressure increases losses significantly. Special attention was paid to description of the behavior and modeling of the losses of variable displacement hydrostatic machines.

  20. Polyploidy induction by hydrostatic pressure shock and embryo development of sea cucumber Apostichopus japonicus

    Institute of Scientific and Technical Information of China (English)

    DING Jun; CHANG Yaqing; WANG Zichen; SONG Jian

    2007-01-01

    The manipulation of the chromosome set for commercially valuable marine animals is important for enhancing aquacultural production. In this study, triploid and tetraploid sea cucumber Apostichopus japonicus were induced by hydrostatic pressure shock, and the conditions of appropriate induction were tested with different starting times, and hydrostatic pressure intensities and durations. The highest rate of triploid induction reached 20% and that of tetraploid was 60%. In consideration of the survival rate and hatch rate, the appropriate treatment for triploid was 55 Mpa of hydrostatic pressure for 5 min at 55 min after fertilization (a.f.), while for tetraploid it was 60 Mpa for 5 min at 61 min a.f. The triploid of the sea cucumber could survive through the pelagic larval stage and attachment stage, and develop like the control group of the experiment. The tetraploid, however, could not survive the attachment stage.

  1. Load-induced error identification of hydrostatic turntable and its influence on machining accuracy

    Institute of Scientific and Technical Information of China (English)

    程强; 任伟达; 刘志峰; 陈东菊; 顾佩华

    2016-01-01

    In heavy duty machine tools, hydrostatic turntable is often used as a means for providing rotational motion and supporting workpiece, so the accuracy of turntable is crucial for part machining. In order to analyze the influence of load-indcued errors on machining accuracy, an identification model of load-induced errors based on the deformation caused by applied load of hydrostatic turntable of computerized numerical control (CNC) gantry milling heavy machine is proposed. Based on multi-body system theory and screw theory, the space machining accuracy model of heavy duty machine tool is established with consideration of identified load-induced errors. And then, the influence of load-induced errors on space machining accuracy and the roundness error of a milled hole is analyzed. The analysis results show that load-induced errors have a big influence on the roundness error of machined hole, especially when the center of the milled hole is far from that of hydrostatic turntable.

  2. Implementation of an approach to replacing the construction hydrostatic test with an alternative integrity validation

    Energy Technology Data Exchange (ETDEWEB)

    Glover, Alan; Purcell, Jennifer; Rudge, Paul; Hudson, Bob [TransCanada PipeLines Ltd., Toronto (Canada)

    2005-07-01

    Hydrostatic testing has been an accepted method of verifying the integrity of newly constructed pipelines prior to putting them in-service since the mid 1950s. Since that time many things have changed that have reduced the incidence of hydrostatic test failures both during the strength and leak testing portion. Critical to these changes have been improvements in pipeline design, materials and construction technology. Using these advancements TransCanada developed an Alternative Integrity Validation (AIV) approach that could be used to replace the field hydrostatic test on natural gas pipelines. This process was validated with key stake holders and the regulatory body (Alberta Energy Utilities Board) and experimental approval was given to apply the approach on a recent pipeline project. The paper will describe the background to the approach, the AIV process and its successful application on an onshore pipeline project completed in March 2005. The paper will also describe the current limitations in applying the approach and path forward. (author)

  3. DEVELOPMENT OF A HYDROSTATIC JOURNAL BEARING WITH SLIT-STEP COMPENSATION

    Energy Technology Data Exchange (ETDEWEB)

    Hale, L C; Donaldson, R R; Castro, C; Chung, C A; Hopkins, D J

    2006-07-28

    This paper describes the mathematical modeling and initial testing of an oil-hydrostatic bearing that derives compensation from both a central radial slit where fluid enters and stepped clearances near each end. Bearings using either a radial slit or stepped clearances for compensation were well studied over forty years ago by Donaldson. These bearings have smooth bores uninterrupted with multiple recesses around the circumference. The present slit-step bearing achieves the best of both types with somewhat higher hydrostatic stiffness than the slit bearing and fluid shear drag lower than the step bearing. This is apparent in TABLE 1, which compares calculated values of initial (i.e., centered) hydrostatic stiffness for each type. The slit-step bearing is one of several types being studied at Lawrence Livermore National Laboratory for possible use on the Precision Optical Grinder and Lathe (POGAL).

  4. Enema reduction of intussusception: the success rate of hydrostatic and pneumatic reduction.

    Science.gov (United States)

    Khorana, Jiraporn; Singhavejsakul, Jesda; Ukarapol, Nuthapong; Laohapensang, Mongkol; Wakhanrittee, Junsujee; Patumanond, Jayanton

    2015-01-01

    Intussusception is a common surgical emergency in infants and children. The incidence of intussusception is from one to four per 2,000 infants and children. If there is no peritonitis, perforation sign on abdominal radiographic studies, and nonresponsive shock, nonoperative reduction by pneumatic or hydrostatic enema can be performed. The purpose of this study was to compare the success rates of both the methods. Two institutional retrospective cohort studies were performed. All intussusception patients (ICD-10 code K56.1) who had visited Chiang Mai University Hospital and Siriraj Hospital from January 2006 to December 2012 were included in the study. The data were obtained by chart reviews and electronic databases, which included demographic data, symptoms, signs, and investigations. The patients were grouped according to the method of reduction followed into pneumatic reduction and hydrostatic reduction groups with the outcome being the success of the reduction technique. One hundred and seventy episodes of intussusception occurring in the patients of Chiang Mai University Hospital and Siriraj Hospital were included in this study. The success rate of pneumatic reduction was 61% and that of hydrostatic reduction was 44% (P=0.036). Multivariable analysis and adjusting of the factors by propensity scores were performed; the success rate of pneumatic reduction was 1.48 times more than that of hydrostatic reduction (P=0.036, 95% confidence interval [CI] =1.03-2.13). Both pneumatic and hydrostatic reduction can be performed safely according to the experience of the radiologist or pediatric surgeon and hospital setting. This study showed that pneumatic reduction had a higher success rate than hydrostatic reduction.

  5. Equilibrium hydrostatic equation and Newtonian limit of the singular f(R) gravity

    CERN Document Server

    Bustelo, A J

    2006-01-01

    We derive the equilibrium hydrostatic equation of a spherical star for any gravitational Lagrangian density of the form $L=\\sqrt{-g}f(R)$. The Palatini variational principle for the Helmholtz Lagrangian in the Einstein gauge is used to obtain the field equations in this gauge. The equilibrium hydrostatic equation is obtained and is used to study the Newtonian limit for $f(R)=R-\\frac{a^{2}}{3R}$. The same procedure is carried out for the more generally case $f(R)=R-\\frac{1}{n+2}\\frac{a^{n+1}}{R^{n}}$ giving a good Newtonian limit.

  6. A Hydrostatic Bearing Test System for Measuring Bearing Load Using Magnetic-Fluid Lubricants.

    Science.gov (United States)

    Weng, Huei Chu; Chen, Lu-Yu

    2016-05-01

    This paper conducts a study on the design of a hydrostatic bearing test system. It involves the determination of viscous properties of magnetic-fluid lubricants. The load of a hydrostatic thrust bearing using a water-based magnetite nanofluid of varying volume flow rate is measured under an applied external induction field via the test system. Results reveal that the presence of nanoparticles in a carrier liquid would cause an enhanced bearing load. Such an effect could be further magnified by increasing the lubricant volume flow rate or the external induction field strength.

  7. [X-ray diffraction study of high hydrostatic pressure on crystalline structure of different type starches].

    Science.gov (United States)

    Liu, Pei-Ling; Shen, Qun; Hu, Xiao-Song; Wu, Ji-Hong

    2012-09-01

    Crystalline changes of different type starches after high hydrostatic pressure treated under 300, 450, 600 MPa were studied by X-ray diffraction. Waxy maize (A type, 100% amylopectin), hylon VII (B type, 30% amylopectin) and tapioca starch (C type, 83% amylopectin) were chosen. The results indicated that for waxy maize starch, annealing effect was observed at 300 MPa, disappearance of crystalline structure happened at 450 MPa and retrogradation at 600 MPa. The results proved that the granule under high hydrostatic pressure processing experiences "three development stages" including annealling effect, disappearance of crystalline structure and recrystalline after granule disintegration.

  8. Influence of load capacity on hydrostatic journal support deformation in finite element calculation

    Institute of Scientific and Technical Information of China (English)

    邵俊鹏; 张艳芹; 李永海; 于晓东; 姜辉

    2008-01-01

    Based on the application of the four-oil-pad radial hydrostatic bearing in heavy equipments, the deformation of the four-oil-pad radial hydrostatic bearing was calculated by using the finite element method. The formula of film stiffness, film thickness and carrying capacity were established; the influence of the main parameters, such as load, load area and deformation on the supportability was analyzed; and the capacity of the two kinds of bearings was compared. The result shows that the carrying capacity of typeⅠ is prior to that of type Ⅱ . Calculations provide a theoretical basis for the bearing choosing and structure designing in the actual project.

  9. Effects of high hydrostatic pressure and thermal processing on bioactive compounds, antioxidant activity, and volatile profile of mulberry juice.

    Science.gov (United States)

    Wang, Fan; Du, Bao-Lei; Cui, Zheng-Wei; Xu, Li-Ping; Li, Chun-Yang

    2017-03-01

    The aim of this study was to investigate the effects of high hydrostatic pressure and thermal processing on microbiological quality, bioactive compounds, antioxidant activity, and volatile profile of mulberry juice. High hydrostatic pressure processing at 500 MPa for 10 min reduced the total viable count from 4.38 log cfu/ml to nondetectable level and completely inactivated yeasts and molds in raw mulberry juice, ensuring the microbiological safety as thermal processing at 85 ℃ for 15 min. High hydrostatic pressure processing maintained significantly (p juice than thermal processing. The main volatile compounds of mulberry juice were aldehydes, alcohols, and ketones. High hydrostatic pressure processing enhanced the volatile compound concentrations of mulberry juice while thermal processing reduced them in comparison with the control. These results suggested that high hydrostatic pressure processing could be an alternative to conventional thermal processing for production of high-quality mulberry juice.

  10. Transcriptomics reveal several gene expression patterns in the piezophile Desulfovibrio hydrothermalis in response to hydrostatic pressure.

    Directory of Open Access Journals (Sweden)

    Amira Amrani

    Full Text Available RNA-seq was used to study the response of Desulfovibrio hydrothermalis, isolated from a deep-sea hydrothermal chimney on the East-Pacific Rise at a depth of 2,600 m, to various hydrostatic pressure growth conditions. The transcriptomic datasets obtained after growth at 26, 10 and 0.1 MPa identified only 65 differentially expressed genes that were distributed among four main categories: aromatic amino acid and glutamate metabolisms, energy metabolism, signal transduction, and unknown function. The gene expression patterns suggest that D. hydrothermalis uses at least three different adaptation mechanisms, according to a hydrostatic pressure threshold (HPt that was estimated to be above 10 MPa. Both glutamate and energy metabolism were found to play crucial roles in these mechanisms. Quantitation of the glutamate levels in cells revealed its accumulation at high hydrostatic pressure, suggesting its role as a piezolyte. ATP measurements showed that the energy metabolism of this bacterium is optimized for deep-sea life conditions. This study provides new insights into the molecular mechanisms linked to hydrostatic pressure adaptation in sulfate-reducing bacteria.

  11. Investigation of Apoptosis Induction in Differentiated PC-12 Cells after Exposure to Hydrostatic Pressure

    Directory of Open Access Journals (Sweden)

    S. Sadri

    2008-01-01

    Full Text Available Objective: Hydrostatic pressure is crucial component of cell environment andfundamental physical quantity, also it is the main factor of both cell integrity andfunction. Pressure variation disorder, beyond physiological limits, may lead topathological states. In this study, we examined the effect of hydrostatic pressureon apoptosis induction, viability, morphology, adhesion potency to substrate andmigration of differentiated PC-12 cells.Materials and Methods: PC-12 as a neuronal cell line maintained in RPMI1640 culture medium supplemented with 10% fetal bovine serum. Staurosporinewas used for differentiating of mitotic PC-12 cells to post mitotic anddifferentiated neuronal cells. Exclusion Dye was used for viability assay, totalneurite length of each cell as well as morphometry. TUNEL staining was alsoperformed for apoptosis detection, adhesion potency of cells to substrate andevaluation of cell migration.Results: Hydrostatic pressure, over physiological limits, induced apoptosis indifferentiated PC-12 cells. It changed cell viability gradually and reduction happenedsignificantly after 24 hours (p<0.05. In compare to the control group, hydrostaticpressure reduced total neurite length, adhesion potency to substrate and migrationof cells in the examined group (p<0.05.Conclusion: Hydrostatic pressure induced apoptosis in differentiated PC-12 cellsas a result of inappropriate interaction between cells and substrate. We proposethat apoptosis in differentiated PC-12 cells may be an anoikis causing to lose theattachment to the substrate.

  12. Neuro-fuzzy control synthesis for hydrostatic type servoactuators. Experimental results

    Directory of Open Access Journals (Sweden)

    Felicia URSU

    2009-12-01

    Full Text Available Continuing recent works of the authors, the paper shows the developing and the application of aneuro-fuzzy control law to the positioning outer loop of a hydrostatic type servoactuator.Experimental results are presented concerning dynamical behavior of the system by using this“intelligent” controller. Finally, arguments about the advantages of the new designed controller aresummarized.

  13. Optical spectroscopic study of Al2O3:Ti3+ under hydrostatic pressure

    NARCIS (Netherlands)

    García-Revilla, S.; Rodríguez, F.; Hernández, I.; Valiente, R.; Pollnau, M.

    2002-01-01

    This work investigates the effect of hydrostatic pressure on the excitation, emission and lifetime of Ti3+-doped Al2O3 in the 0–110 kbar range. The application of pressure induces band shifts that are correlated with the corresponding local structural changes undergone by the TiO6 complex. The incre

  14. Hydrostatic compression of galenobismutite (PbBi2S4)

    DEFF Research Database (Denmark)

    Olsen, Lars Arnskov; Balic Zunic, Tonci; Makovicky, Emil;

    2007-01-01

    A single-crystal sample of galenobismutite was subjected to hydrostatic pressures in the range of 0.0001 and 9 GPa at room temperature using the diamond-anvil cell technique. A series of X-ray diVraction intensities were collected at ten distinct pressures using a CCD equipped 4-circle diVractome...

  15. Effects of high hydrostatic pressure on genomic expression profiling of porcine parthenogenetic activated and cloned embryos

    DEFF Research Database (Denmark)

    Lin, Lin; Luo, Yonglun; Sørensen, Peter

    2014-01-01

    Handmade cloning (HMC) has been used to generate transgenic pigs for biomedical research. Recently, we found that parthenogenetic activation (PA) of porcine oocytes and improved HMC efficiency could be achieved by treatment with sublethal high hydrostatic pressure (HHP). However, the molecular...

  16. The behavior of high-strength unidirectional composites under tension with superposed hydrostatic pressure

    NARCIS (Netherlands)

    Zinoviev, P.A.; Tsvetkov, S.V.; Kulish, G.G.; Berg, van den R.W.; Schepdael, van L.J.M.M.

    2001-01-01

    Three types of high-strength unidirectional composite materials were studied under longitudinal tension with superposed high hydrostatic pressure. Reinforcing fibers were T1000G carbon, S2 glass and Zylon PBO fibers; the Ciba 5052 epoxy resin was used as matrix. The composites were tested under exte

  17. Initial and Boundary Value Problems for Two-Dimensional Non-hydrostatic Boussinesq Equations

    Institute of Scientific and Technical Information of China (English)

    沈春; 孙梅娜

    2005-01-01

    Based on the theory of stratification, the weU-posedness of the initial and boundary value problems for the system of twodimensional non-hydrostatic Boussinesq equations was discussed. The sufficient and necessary conditions of the existence and uniqueness for the solution of the equations were given for some representative initial and boundary value problems. Several special cases were discussed.

  18. Hydrostatic Pressure Project: Linked-Class Problem-Based Learning in Engineering

    Science.gov (United States)

    Davis, Freddie J.; Lockwood-Cooke, Pamela; Hunt, Emily M.

    2011-01-01

    Over the last few years, WTAMU Mathematics, Engineering and Science faculty has used interdisciplinary projects as the basis for implementation of a linked-class approach to Problem-Based Learning (PBL). A project that has significant relevance to engineering statics, fluid mechanics, and calculus is the Hydrostatic Pressure Project. This project…

  19. Ductile tearing of crack-like defects during hydrostatic testing of pipes

    Energy Technology Data Exchange (ETDEWEB)

    Hippert, E.; Donato, G.V.P.; Teixeira, J.C.G.; Lima de, R.S. [Petrobras, Rio de Janeiro (Brazil)

    2004-07-01

    Although hydrostatic testing is widely used to monitor pipeline integrity, experimental studies have shown that flaw growth can occur during hydrostatic testing procedures. This study investigated the effect of pipeline hydrostatic testing on ductile crack growth of prior crack-like defects. Six segments of 3 m length API X60 steel pipes were tested. Each segment contained an electro-sparking erosion part-wall defects positioned both externally and internally on the base metal. Crack extension for external part-wall defects was monitored using an ultrasonic technique. Pipe resistance curves of applied load versus crack depth were obtained for each crack configuration. Laboratory curves were obtained from fracture mechanics tests pieces and then used to determine the initiation of stable extension of the applied load defects. It was observed that the level of crack tip constraint and triaxiality were similar to those experienced in real structures. It was suggested that single edge notch tensile (SET) specimens may be the most suitable specimens for predicting pipeline toughness behavior. A suitable parameter for estimating hydrostatic testing pressure was derived from values obtained during Charpy V-notch impact testing. It was concluded that future research will focus on the development of SET specimens and testing methods. 12 refs., 4 tabs., 11 figs.

  20. High hydrostatic pressure as a method to preserve fresh-cut Hachiya persimmons: A structural approach.

    Science.gov (United States)

    Vázquez-Gutiérrez, José Luis; Quiles, Amparo; Vonasek, Erica; Jernstedt, Judith A; Hernando, Isabel; Nitin, Nitin; Barrett, Diane M

    2016-12-01

    The "Hachiya" persimmon is the most common astringent cultivar grown in California and it is rich in tannins and carotenoids. Changes in the microstructure and some physicochemical properties during high hydrostatic pressure processing (200-400 MPa, 3 min, 25 ℃) and subsequent refrigerated storage were analyzed in this study in order to evaluate the suitability of this non-thermal technology for preservation of fresh-cut Hachiya persimmons. The effects of high-hydrostatic pressure treatment on the integrity and location of carotenoids and tannins during storage were also analyzed. Significant changes, in particular diffusion of soluble compounds which were released as a result of cell wall and membrane damage, were followed using confocal microscopy. The high-hydrostatic pressure process also induced changes in physicochemical properties, e.g. electrolyte leakage, texture, total soluble solids, pH and color, which were a function of the amount of applied hydrostatic pressure and may affect the consumer acceptance of the product. Nevertheless, the results indicate that the application of 200 MPa could be a suitable preservation treatment for Hachiya persimmon. This treatment seems to improve carotenoid extractability and tannin polymerization, which could improve functionality and remove astringency of the fruit, respectively. © The Author(s) 2016.

  1. High hydrostatic pressure treatment of porcine oocytes before handmade cloning improves developmental competence and cryosurvival

    DEFF Research Database (Denmark)

    Dupont, Yoko; Lin, Lin; Schmidt, Mette

    2008-01-01

    and cryotolerance of embryos produced by handmade cloning (HMC) after pressure treatment of recipient oocytes. In vitro-matured porcine oocytes were treated with a sublethal hydrostatic pressure of 20 MPa (200 times greater than atmospheric pressure) and recovered for either 1 or 2 h (HHP1 and HHP2 groups...

  2. Ill-Posedness of the Hydrostatic Euler and Singular Vlasov Equations

    Science.gov (United States)

    Han-Kwan, Daniel; Nguyen, Toan T.

    2016-09-01

    In this paper, we develop an abstract framework to establish ill-posedness, in the sense of Hadamard, for some nonlocal PDEs displaying unbounded unstable spectra. We apply this to prove the ill-posedness for the hydrostatic Euler equations as well as for the kinetic incompressible Euler equations and the Vlasov-Dirac-Benney system.

  3. Effect of high hydrostatic pressure processing on in vitro digestion of milk proteins and fats

    Science.gov (United States)

    The use of high hydrostatic pressure processing (HPP) is increasing in popularity in the food industry. Its ability to modify milk proteins and fats suggests that it may be useful in creating foods that suppress appetite; however, its effect on the digestibility of proteins and fats is unclear. The...

  4. The hydrostatic pressure indifference point underestimates orthostatic redistribution of blood in humans

    DEFF Research Database (Denmark)

    Petersen, L G; Carlsen, Jonathan F.; Nielsen, Michael Bachmann

    2014-01-01

    The hydrostatic indifference point (HIP; where venous pressure is unaffected by posture) is located at the level of the diaphragm and is believed to indicate the orthostatic redistribution of blood, but it remains unknown whether HIP coincides with the indifference point for blood volume (VIP). D...

  5. Behavior of plant plasma membranes under hydrostatic pressure as monitored by fluorescent environment-sensitive probes.

    Science.gov (United States)

    Roche, Yann; Klymchenko, Andrey S; Gerbeau-Pissot, Patricia; Gervais, Patrick; Mély, Yves; Simon-Plas, Françoise; Perrier-Cornet, Jean-Marie

    2010-08-01

    We monitored the behavior of plasma membrane (PM) isolated from tobacco cells (BY-2) under hydrostatic pressures up to 3.5kbar at 30 degrees C, by steady-state fluorescence spectroscopy using the newly introduced environment-sensitive probe F2N12S and also Laurdan and di-4-ANEPPDHQ. The consequences of sterol depletion by methyl-beta-cyclodextrin were also studied. We found that application of hydrostatic pressure led to a marked decrease of hydration as probed by F2N12S and to an increase of the generalized polarization excitation (GPex) of Laurdan. We observed that the hydration effect of sterol depletion was maximal between 1 and 1.5 kbar but was much less important at higher pressures (above 2 kbar) where both parameters reached a plateau value. The presence of a highly dehydrated gel state, insensitive to the sterol content, was thus proposed above 2.5 kbar. However, the F2N12S polarity parameter and the di-4-ANEPPDHQ intensity ratio showed strong effect on sterol depletion, even at very high pressures (2.5-3.5 kbar), and supported the ability of sterols to modify the electrostatic properties of membrane, notably its dipole potential, in a highly dehydrated gel phase. We thus suggested that BY-2 PM undergoes a complex phase behavior in response to the hydrostatic pressure and we also emphasized the role of phytosterols to regulate the effects of high hydrostatic pressure on plant PM.

  6. Hydrostatic Pressure Affects In Vitro Maturation of Oocytes and Follicles and Increases Granulosa Cell Death

    Directory of Open Access Journals (Sweden)

    Isac Karimi

    2013-01-01

    Full Text Available Objective: This study examines the effects of hydrostatic pressure on in vitro maturation (IVM of oocytes derived from in vitro grown follicles.Materials and Methods: In this experimental study, preantral follicles were isolated from 12-day-old female NMRI mice. Each follicle was cultured individually in Alpha Minimal Essential Medium (α-MEM under mineral oil for 12 days. Then, follicles were induced for IVM and divided into two groups, control and experiment. In the experiment group follicles were subjected to 20 mmHg pressure for 30 minutes and cultured for 24-48 hours. We assessed for viability and IVM of the oocytes. The percentage of apoptosis in cumulus cells was determined by the TUNEL assay. A comparison between groups was made using the student’s t test.Results: The percentage of metaphase II oocytes (MII increased in hydrostatic pressure-treated follicles compared to controls (p<0.05. Cumulus cell viability reduced in hydrostatic pressure-treated follicles compared to controls (p<0.05. Exposure of follicles to pressure increased apoptosis in cumulus cells compared to controls (p<0.05.Conclusion: Hydrostatic pressure, by inducing apoptosis in cumulus cells, participates in the cumulus oocyte coupled relationship with oocyte maturation.

  7. Beta-adrenergic agonist therapy accelerates the resolution of hydrostatic pulmonary edema in sheep and rats.

    Science.gov (United States)

    Frank, J A; Wang, Y; Osorio, O; Matthay, M A

    2000-10-01

    To determine whether beta-adrenergic agonist therapy increases alveolar liquid clearance during the resolution phase of hydrostatic pulmonary edema, we studied alveolar and lung liquid clearance in two animal models of hydrostatic pulmonary edema. Hydrostatic pulmonary edema was induced in sheep by acutely elevating left atrial pressure to 25 cmH(2)O and instilling 6 ml/kg body wt isotonic 5% albumin (prepared from bovine albumin) in normal saline into the distal air spaces of each lung. After 1 h, sheep were treated with a nebulized beta-agonist (salmeterol) or nebulized saline (controls), and left atrial pressure was then returned to normal. beta-Agonist therapy resulted in a 60% increase in alveolar liquid clearance over 3 h (P Ringer lactate). beta-Agonist therapy resulted in a significant decrease in excess lung water (P < 0.01) and significant improvement in arterial blood gases by 2 h (P < 0.03). These preclinical experimental studies support the need for controlled clinical trials to determine whether beta-adrenergic agonist therapy would be of value in accelerating the resolution of hydrostatic pulmonary edema in patients.

  8. Critical current density in wire drawn and hydrostatically extruded Nb-Ti superconductors

    Science.gov (United States)

    Alterovitz, S. A.; Woollam, J. A.; Collings, E. W.

    1979-01-01

    Critical current studies have been made on copper-clad Nb-Ti composite wire prepared under area reductions of 100:1 and 10,000:1 by hydrostatic extrusion (HE), wire drawing and HE plus drawing. Comparative evaluation of the thermomechanical processing equivalent of HE was performed.

  9. First-principles simulations on bonding pathways of chemical transformations under hydrostatic compression

    Science.gov (United States)

    Hu, Anguang; Zhang, Fan

    2012-02-01

    High pressure as a thermodynamic parameter provides a strong structural constraint to lead chemical transformations with selective ways. Thus, chemical transformations under pressure can create novel materials which may not be accessible by covalent synthesis. However, bonding evolution toward high pressure chemical transformations can be a complex process and may happen over widely different pressures. To understand bonding evolution pathways of high pressure chemical transformations, first-principles simulations were performed following hydrostatic compression enthalpy minimization paths to obtain experimentally and theoretically established phase transitions of carbon. The results showed that the chemical transformations from hydrostatic compression carbon to single-bonded phases were characterized by a sudden decrease in principal stress components, indicating the onset of chemical transformation. On this basis, a number of hydrostatic compression chemical transformations from molecular precursors to novel materials were predicted, such as hydrocarbon graphane, a hydrogenated carbon nitride sheet, and carbon nitrides. All predicted hydrostatic compression transformations are featured as a sudden change in principal stress components, representing chemical bonding destruction and formation reactions with a cell volume collapse.

  10. Solidification and loss of hydrostaticity in liquid media used for pressure measurements

    Science.gov (United States)

    Torikachvili, M. S.; Kim, S. K.; Colombier, E.; Bud'ko, S. L.; Canfield, P. C.

    2015-12-01

    We carried out a study of the pressure dependence of the solidification temperature in nine pressure transmitting media that are liquid at ambient temperature, under pressures up to 2.3 GPa. These fluids are 1:1 isopentane/n-pentane, 4:6 light mineral oil/n-pentane, 1:1 isoamyl alcohol/n-pentane, 4:1 methanol/ethanol, 1:1 FC72/FC84 (Fluorinert), Daphne 7373, isopentane, and Dow Corning PMX silicone oils 200 and 60 000 cS. We relied on the high sensitivity of the electrical resistivity of Ba(Fe1-xRux)2As2 single crystals to the freezing of the pressure media and cross-checked with corresponding anomalies observed in the resistance of the manganin coil that served as the ambient temperature resistive manometer. In addition to establishing the temperature-pressure line separating the liquid (hydrostatic) and frozen (non-hydrostatic) phases, these data permit rough estimates of the freezing pressure of these media at ambient temperature. This pressure establishes the extreme limit for the medium to be considered hydrostatic. For higher applied pressures, the medium has to be treated as non-hydrostatic.

  11. The significance of the activity of dissolved oxygen, and other gases, enhanced by high hydrostatic pressure.

    Science.gov (United States)

    Ludwig, Horst; Macdonald, Alister G

    2005-04-01

    The partial pressure of oxygen and other gases dissolved in water and subjected to high hydrostatic pressure is increased. Although this was established many years ago it remains a problematical phenomenon. The review deals with some of the underlying theoretical difficulties and discusses the kinetic and environmental implications of the pressure-enhanced partial pressures.

  12. Thermal Fluid-Solid Interaction Model and Experimental Validation for Hydrostatic Mechanical Face Seals

    Institute of Scientific and Technical Information of China (English)

    HUANG Weifeng; LIAO Chuanjun; LIU Xiangfeng; SUO Shuangfu; LIU Ying; WANG Yuming

    2014-01-01

    Hydrostatic mechanical face seals for reactor coolant pumps are very important for the safety and reliability of pressurized-water reactor power plants. More accurate models on the operating mechanism of the seals are needed to help improve their performance. The thermal fluid-solid interaction (TFSI) mechanism of the hydrostatic seal is investigated in this study. Numerical models of the flow field and seal assembly are developed. Based on the mechanism for the continuity condition of the physical quantities at the fluid-solid interface, an on-line numerical TFSI model for the hydrostatic mechanical seal is proposed using an iterative coupling method. Dynamic mesh technology is adopted to adapt to the changing boundary shape. Experiments were performed on a test rig using a full-size test seal to obtain the leakage rate as a function of the differential pressure. The effectiveness and accuracy of the TFSI model were verified by comparing the simulation results and experimental data. Using the TFSI model, the behavior of the seal is presented, including mechanical and thermal deformation, and the temperature field. The influences of the rotating speed and differential pressure of the sealing device on the temperature field, which occur widely in the actual use of the seal, are studied. This research proposes an on-line and assembly-based TFSI model for hydrostatic mechanical face seals, and the model is validated by full-sized experiments.

  13. Experimental equipment for measuring physical properties of the annular hydrostatic thrust bearing

    Directory of Open Access Journals (Sweden)

    Kozdera Michal

    2014-03-01

    Full Text Available The hydraulic circuit, through which the mineral oil is brought, is an important part of hydrostatic bearings. The annular hydrostatic thrust bearing consists of two sliding plates divided by a layer of mineral oil. In the lower plate, there are oil grooves which distribute the liquid between the sliding areas. The hydraulic circuit is made of two basic parts: the energy source and the controlling part. The hydraulic pump, which brings the liquid into the sliding bearing, is the source of the pressure energy. The sliding bearing is weighted down by axial force, which can be changed during the process. That´s why in front of the particular oil grooves control components adjusting pressure and flow size are located. This paper deals with a project of a hydraulic circuit for regulation of fluid layer in the annular hydrostatic thrust bearing and the testing equipment for measuring its physical properties. It will include the issue of measuring loading capacity and height of the fluid layer in the annular hydrostatic thrust bearing.

  14. Strength Differential Measured in Inconel 718: Effects of Hydrostatic Pressure Studied

    Science.gov (United States)

    Lewandowski, John J.; Wesseling, Paul; Prabhu, Nishad S.; Larose, Joel; Lissenden, Cliff J.; Lerch, Bradley A.

    2003-01-01

    Aeropropulsion components, such as disks, blades, and shafts, are commonly subjected to multiaxial stress states at elevated temperatures. Experimental results from loadings as complex as those experienced in service are needed to help guide the development of accurate viscoplastic, multiaxial deformation models that can be used to improve the design of these components. During a recent study on multiaxial deformation (ref. 1) on a common aerospace material, Inconel 718, it was shown that the material in the aged state exhibits a strength differential effect (SDE), whereby the uniaxial compressive yield and subsequent flow behavior are significantly higher than those in uniaxial tension. Thus, this material cannot be described by a standard von Mises yield formulation. There have been other formulations postulated (ref. 2) that involve other combinations of the stress invariants, including the effect of hydrostatic stress. The question remained as to which invariants are necessary in the flow model. To capture the physical mechanisms occurring during deformation and reflect them in the plasticity formulation, researchers examined the flow of Inconel 718 under various amounts of hydrostatic stress to determine whether or not hydrostatic stress is needed in the formulation. Under NASA Grant NCC3-464, monitored by the NASA Glenn Research Center, a series of tensile tests were conducted at Case Western Reserve University on aged (precipitation hardened) Inconel 718 at 650 C and with superimposed hydrostatic pressure. Dogbone shaped tensile specimens (3-mm-diameter gauge by 16-mm gauge length) and cylindrical compression specimens (3-mm-diameter gauge by 6-mm gauge length) were strain gauged and loaded in a high-pressure testing apparatus. Hydrostatic pressures were obtained with argon and ranged from 210 to 630 MPa. The aged Inconel 718 showed a pronounced difference in the tension and compression yield strength (i.e., an SDE), as previously observed. Also, there were

  15. Enema reduction of intussusception: the success rate of hydrostatic and pneumatic reduction

    Directory of Open Access Journals (Sweden)

    Khorana J

    2015-12-01

    Full Text Available Jiraporn Khorana,1 Jesda Singhavejsakul,1 Nuthapong Ukarapol,2 Mongkol Laohapensang,3 Junsujee Wakhanrittee,4 Jayanton Patumanond5 1Division of Pediatric Surgery, Department of Surgery, 2Division of Gastroenterology, Department of Pediatrics, Chiang Mai University Hospital, Chiang Mai, 3Division of Pediatric Surgery, Department of Surgery, Siriraj Hospital, Mahidol University, Bangkok, 4Division of Pediatric Surgery, Department of Surgery, Thammasat University Hospital, 5Center of Excellence in Applied Epidemiology, Thammasat University Hospital, Pathumthani, Thailand Purpose: Intussusception is a common surgical emergency in infants and children. The incidence of intussusception is from one to four per 2,000 infants and children. If there is no peritonitis, perforation sign on abdominal radiographic studies, and nonresponsive shock, nonoperative reduction by pneumatic or hydrostatic enema can be performed. The purpose of this study was to compare the success rates of both the methods.Methods: Two institutional retrospective cohort studies were performed. All intussusception patients (ICD-10 code K56.1 who had visited Chiang Mai University Hospital and Siriraj Hospital from January 2006 to December 2012 were included in the study. The data were obtained by chart reviews and electronic databases, which included demographic data, symptoms, signs, and investigations. The patients were grouped according to the method of reduction followed into pneumatic reduction and hydrostatic reduction groups with the outcome being the success of the reduction technique.Results: One hundred and seventy episodes of intussusception occurring in the patients of Chiang Mai University Hospital and Siriraj Hospital were included in this study. The success rate of pneumatic reduction was 61% and that of hydrostatic reduction was 44% (P=0.036. Multivariable analysis and adjusting of the factors by propensity scores were performed; the success rate of pneumatic reduction

  16. Comparison of Simulated Microgravity and Hydrostatic Pressure for Chondrogenesis of hASC.

    Science.gov (United States)

    Mellor, Liliana F; Steward, Andrew J; Nordberg, Rachel C; Taylor, Michael A; Loboa, Elizabeth G

    2017-04-01

    Cartilage tissue engineering is a growing field due to the lack of regenerative capacity of native tissue. The use of bioreactors for cartilage tissue engineering is common, but the results are controversial. Some studies suggest that microgravity bioreactors are ideal for chondrogenesis, while others show that mimicking hydrostatic pressure is crucial for cartilage formation. A parallel study comparing the effects of loading and unloading on chondrogenesis has not been performed. The goal of this study was to evaluate chondrogenesis of human adipose-derived stem cells (hASC) under two different mechanical stimuli relative to static culture: microgravity and cyclic hydrostatic pressure (CHP). Pellets of hASC were cultured for 14 d under simulated microgravity using a rotating wall vessel bioreactor or under CHP (7.5 MPa, 1 Hz, 4 h · d-1) using a hydrostatic pressure vessel. We found that CHP increased mRNA expression of Aggrecan, Sox9, and Collagen II, caused a threefold increase in sulfated glycosaminoglycan production, and resulted in stronger vimentin staining intensity and organization relative to microgravity. In addition, Wnt-signaling patterns were altered in a manner that suggests that simulated microgravity decreases chondrogenic differentiation when compared to CHP. Our goal was to compare chondrogenic differentiation of hASC using a microgravity bioreactor and a hydrostatic pressure vessel, two commonly used bioreactors in cartilage tissue engineering. Our results indicate that CHP promotes hASC chondrogenesis and that microgravity may inhibit hASC chondrogenesis. Our findings further suggest that cartilage formation and regeneration might be compromised in space due to the lack of mechanical loading.Mellor LF, Steward AJ, Nordberg RC, Taylor MA, Loboa EG. Comparison of simulated microgravity and hydrostatic pressure for chondrogenesis of hASC. Aerosp Med Hum Perform. 2017; 88(4):377-384.

  17. MATHEMATICAL AND COMPUTER MODELING OF AUTOMATIC CONTROL SYSTEM FOR HYDROSTATIC BEARING

    Directory of Open Access Journals (Sweden)

    N. A. Pelevin

    2016-09-01

    Full Text Available The paper presents simulation results of hydrostatic bearing dynamics in spindle assembly of standard flexible production module with throttled circuit. The necessity of dynamic quality increase for automatic control system of the hydrostatic bearing with the use of correcting means in the form of RC-chains is shown. The features of correction parameters choice coming from the existence of the crossing connections in automatic control system structure are noted. We propose the block diagram of automatic control system of the hydrostatic bearing in Simulink working field and cyclic algorithm for determination program of RC-chain parameters implemented in MATLAB taking into account typical thermal processes for the finishing treatment. Graphic-analytical method for the correction parameters choice is presented based on the stability stock phase gradient for dynamic quality determination of automatic control system. Researches of the method estimability in case of using the standard metal bellow valve as the hydrocapacity for RC-chain are also carried out. Recommendations for the bellow valve choice are formulated. The check of dynamic quality indicators concerning transition processes calculated by means of the appropriate programs developed for MATLAB is performed. Examples are given for phase stability factor gradient schedules with partition of various areas of hydrostatic bearing dynamic quality for different frequencies of spindle rotation and procedure description of data cursor function application on MATLAB toolbar. Improvement of hydrostatic bearing dynamics under typical low loadings for finishing treatment is noted. Also, decrease of dynamic indicators for high loadings treatment in case of roughing treatment is marked.

  18. Effect of working position on vertical motion straightness of open hydrostatic guideways in grinding machine

    Science.gov (United States)

    Zha, Jun; Wang, Zhiwei; Xue, Fei; Chen, Yaolong

    2016-08-01

    Hydrostatic guideways have various applications in precision machine tools due to their high motion accuracy. The analysis of motion straightness in hydrostatic guideways is generally ignoring the external load on the slider. A variation force also exists, caused by the different working positions, together with the dead load of the slider and that of other auxiliary devices. The effect of working position on vertical motion straightness is investigated based on the equivalent static model, considering the error averaging effort of pressured oil film in open hydrostatic guideways. Open hydrostatic guideways in LGF1000 are analyzed with this approach. The theoretical results show that the slider has maximum vertical motion straightness when the working position is closer the guiderail of Y axis. The vertical motion straightness reaches a minimum value as the working position is located at the center of the two guiderails on the Y axis. The difference between the maximum and minimum vertical motion straightness is 34.7%. The smaller vertical motion straightness is attributed to the smaller spacing of the two pads centers, along the Y direction. The experimental results show that the vertical motion straightness is 4.15 μm/1200 mm, when the working position is located in the middle of the X beam, and 5.08 μm/1200 mm, when the working position is approaching the Y guiderails, denoting an increase of 18.3%. The changing trends of the measured results validate the correctness of the theoretical model. The research work can be used to reveal the variation law of accuracy of the open hydrostatic guideways, under different working positions, to predict the machining precision, and provides the basis for an error compensation strategy for gantry type grinding machines.

  19. Efficiency of the Ultrasound Guided Hydrostatic Reduction of Intussusception with Normal Saline

    Directory of Open Access Journals (Sweden)

    Azim Motamed Far

    2010-05-01

    Full Text Available Background/Objective: Conventional hydrostatic barium reduction or pneumatic reduction of intussusception is associated with considerable ionizing radiation. The aim of this study was to evaluate ultrasound guided hydrostatic reduction of childhood intussusceptions using water enema."nPatients and Methods: The reduction was attempted using a warm water reservoir at a height of 80-120 cm above the table. The vital signs and the abrupt accumulation of liquid in the abdomen were controlled during the procedure. Reduction of intussuscepted loops was controlled by sonography, the observed fluid surrounding the intussusception was gradually reduced through the ileocecal valve. The procedure was continued until the intussusceptum disappeared completely and the distal ileum was filled with water. The reduction was stopped for 10-15 minutes in those patients in whom the procedure failed after a 10-minute effort. Then the procedure was applied for maximum three times and manual abdominal palpation was applied in some patients to ease the reduction. After successful reduction, the abdomen was re-examined to detect any lead point or recurrence of intussusception. The patients were then transferred to the surgery ward and after 24 hours, the regular oral diet was started and the patients were discharged. Partially reduced cases of intussusception underwent surgical treatment. Fisher exact test was used for the assessment of the relation between intussusception sites and the hydrostatic reduction outcome and/or presence of gangrenous bowel."nResults: Complete reduction was achieved in 21 of 24 patients (87.5%. Hydrostatic reduction was impossible in three patients, bowel resection was performed in 2 patients and the intussusceptions were surgically reduced in one patient."nConclusion: Intussusception is the most common abdominal emergency of early childhood for which non-operative reduction is currently the treatment of choice."nKeywords: Intussusception

  20. Effect of working position on vertical motion straightness of open hydrostatic guideways in grinding machine

    Science.gov (United States)

    Zha, Jun; Wang, Zhiwei; Xue, Fei; Chen, Yaolong

    2017-01-01

    Hydrostatic guideways have various applications in precision machine tools due to their high motion accuracy. The analysis of motion straightness in hydrostatic guideways is generally ignoring the external load on the slider. A variation force also exists, caused by the different working positions, together with the dead load of the slider and that of other auxiliary devices. The effect of working position on vertical motion straightness is investigated based on the equivalent static model, considering the error averaging effort of pressured oil film in open hydrostatic guideways. Open hydrostatic guideways in LGF1000 are analyzed with this approach. The theoretical results show that the slider has maximum vertical motion straightness when the working position is closer the guiderail of Y axis. The vertical motion straightness reaches a minimum value as the working position is located at the center of the two guiderails on the Y axis. The difference between the maximum and minimum vertical motion straightness is 34.7%. The smaller vertical motion straightness is attributed to the smaller spacing of the two pads centers, along the Y direction. The experimental results show that the vertical motion straightness is 4.15 μm/1200 mm, when the working position is located in the middle of the X beam, and 5.08 μm/1200 mm, when the working position is approaching the Y guiderails, denoting an increase of 18.3%. The changing trends of the measured results validate the correctness of the theoretical model. The research work can be used to reveal the variation law of accuracy of the open hydrostatic guideways, under different working positions, to predict the machining precision, and provides the basis for an error compensation strategy for gantry type grinding machines.

  1. 二次调节静液传动系统在试验技术中的应用%The Application of the Hydrostatic Transmission System with Secondary Regulation in the Test Technique

    Institute of Scientific and Technical Information of China (English)

    姜继海; 赵春涛

    2001-01-01

    The paper presents the investigation and development situation of hydrostatic transmission system with secondary regulation abroad and at home.On the basis of describing and discussing the working principle and characteristics of the hydrostatic transmission system with secondary regulation in detail, the construction, working principles and characteristics of the test system applying the hydrostatic transmission system with secondary regulation are also introduced in detail in the paper. The future application of this technology in test system is evaluated at last.%介绍了二次调节静液传动技术在国内外的研究、发展概况,对二次调节静液传动技术的工作原理及其特点进行了较详细的论述,在此基础上对采用二次调节静液传动技术试验系统的结构、工作原理及特点进行了详细的介绍,并对该技术在试验技术中的应用前景进行了展望。

  2. Development and Application of Hydrostatic Functional Components%液体静压功能部件发展及应用

    Institute of Scientific and Technical Information of China (English)

    潘高星

    2013-01-01

    The development status and application in high level CNC machine tool of hydrostatic functional components including hydrostatic guideway,hydrostatic screw,hydrostatic spindle and hydrostatic rotary worktable,were introduced.%主要阐述了液体静压功能部件包括静压导轨、静压丝杠、静压主轴、静压转台的发展现状以及在高端数控金属切削机床上的应用。

  3. Performance Study of Dynamic-hydrostatic Hybrid Gas Seal%动静压混合式气体密封的特性分析

    Institute of Scientific and Technical Information of China (English)

    李双喜; 张树强; 蔡纪宁; 张秋翔

    2011-01-01

    Based on the principles of dynamic gas seal and hydrostatic gas seal,a new kind of gas seal,namely dynamic-hydrostatic hybrid gas seal(DHHGS),was proposed.Gas film pressure distribution between the two faces of dynamic seal,hydrostatic seal and DHHGS were obtained by solving the Reynolds equation of the gas film numerically.The sealing performance parameters,i.e.opening force,steady-state stiffness,leakage rate and frictional power were evaluated.Operating characteristics of DHHGS were investigated by comparing the sealing performances of different structure of seal end faces of DHHGS,hydrostatic seal and dynamic seal.Specifically sealing performances of DHHGS and hydrostatic seal without initial gas pressure were analyzed.Results showed that the opening force of DHHGS was larger in the same gas film thickness and the stiffness of DHHGS was still greater when the gas film thickness increased,compared with dynamic seal.Static opening and dynamic running could be well achieved with DHHGS.As it has both the hydrodynamic effect and hydrostatic effect simultaneously,DHHGS could find more applications in engineering.In addition the sealing performance,parameters of DHHGS could be changed through gas source pressure adjustment online.%基于气体动压式和静压式密封原理,提出了新型的动静压混合式气体密封(简称混合式密封),介绍了该密封的工作原理.采用有限元法,利用Matlab数值软件,求解了混合式密封及动压式密封和静压式密封端面间气膜的Reynolds方程,得到气膜的压力分布,进而求得了密封的性能参数,如开启力、稳态刚度、泄漏率、摩擦功耗等.比较了不同端面结构的混合式密封与静压式和动压式密封的密封性能,并分析了混合式密封及静压式密封在失去气源情况下的密封性能.结果表明:与动压式密封相比,在同一气膜厚度下混合式密封获得的开启力更大,气膜厚度增加时仍具有

  4. 静压支承摩擦副温度场模拟与实验%Numerical and Experimental Study on Temperature Field of Hydrostatic Bearing Friction Pairs

    Institute of Scientific and Technical Information of China (English)

    于晓东; 吴晓刚; 隋甲龙; 孙丹丹; 张艳芹

    2016-01-01

    为了研究静压支承摩擦副温度场,基于摩擦学和传热学理论,采用流固耦合方法对圆形腔静压支承摩擦副的温度分布规律及其速度特性进行研究,并进行实验验证。结果表明:间隙油膜在挤压和剪切以及泵功耗联合作用下产生的热,通过流固耦合方式传递给静压导轨和油垫,进而扩散到整个旋转工作台和底座。间隙油膜接触处摩擦副温度最高,向四周扩散温度逐渐降低。随着旋转工作台转速增加,油膜温度上升,工作台上表面和侧面温度下降,并趋于平缓,底座侧面温度从下到上先升高后降低。旋转速度由10 r/min增加至80 r/min时旋转工作台最高温升为6.8℃,底座最高温升为3.5℃,因而旋转速度对支承摩擦副温度场影响不能忽略。并将实验结果与模拟值进行比较,温度相对误差均在4%以下,满足工程实践要求。%In order to study temperature field of hydrostatic bearing friction pairs,temperature distribution and its speed characteristics of hydrostatic bearing friction pairs with circular recess are analyzed by adopting the method of fluid-structure interaction based on tribology theory and heat transfer,and a verification experiment is carried on. Due to the joint action of oil film extrusion, oil shear and pump power consumption, and a large amount of heat is generated in the oil film clearance during the operation of hydrostatic thrust bearing , and heat is passed to the hydrostatic slideway and pad by way of fluid-solid interaction,and then heat spreads to the en⁃tire rotational workbench and base. The temperature of friction pairs is the highest in the place that is contacting with oil film clearance, and temperature decreases gradually to all around. The results have been found that by increasing the rotational speed oil film temperature increased,and temperature of upper surface and side surface is decreased,and then tends to be steady

  5. Biochemical changes during the storage of high hydrostatic pressure processed avocado paste.

    Science.gov (United States)

    Jacobo-Velázquez, D A; Hernández-Brenes, C

    2010-08-01

    High hydrostatic pressure (HHP) processing improves the shelf life of avocado paste without a significant impact on flavor; however, scarce information is available on biochemical modifications during its extended storage period. The present study focused on the changes in oxidative enzyme activities of pressurized avocado paste (600 MPa for 3 min) during refrigerated storage (45 d at 4 degrees C). Aerobic plate counts (APC), lactic acid bacteria counts (LAB), pH, and instrumental color were also evaluated during storage. Processing with HHP caused a decrease in polyphenol oxidase (PPO) and lipoxygenase (LOX) activities, resulting in residual enzyme levels of 50.72% and 55.16%, respectively. Although instrumental color values didn't change significantly during the evaluated storage period, both enzymes (PPO and LOX) recuperated their activities at 10 to 15 d of storage, reached the original values observed in the fresh paste, and then started a declining phase until the end of the storage period. Pulp pH presented a consistent decline during the first 20 d of storage. LAB counts were very low during storage, discarding lactic acid production as responsible for the observed pH decline. Enzyme reactivation, cell disruption, and a gradual migration of intracellular components such as organic acids are herein proposed as the main mechanisms for the deterioration of HHP treated avocado paste during its refrigerated storage. Practical Application: At the present, HHP is the most effective commercial nonthermal technology to process avocado paste when compared to thermal and chemical alternatives. Although it has proven to be an excellent product-technology match, little information is known on the biochemical changes that take place in the product during its refrigerated shelf life. Biochemical reactions during storage are important, since they can influence avocado paste nutritional and flavor qualities at the time of product consumption. The present study reports for

  6. 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.

  7. Upregulation of aggrecan and type II collagen mRNA expression in bovine chondrocytes by the application of hydrostatic pressure.

    Science.gov (United States)

    Toyoda, Takashi; Seedhom, Bahaa B; Kirkham, Jennifer; Bonass, William A

    2003-01-01

    The aim of this study was to investigate the effect of hydrostatic pressure on the expression of messenger ribonucleic acid (mRNA) for specific extracellular matrix proteins in chondrocytes. Chondrocytes obtained from bovine metatarsophalangeal joints were embedded in cylindrical 2% agarose gels. A novel experimental system was used to apply 5 MPa of static hydrostatic pressure to these chondrocytes for 4 hours. The application of hydrostatic pressure caused a significant increase in the level of aggrecan mRNA by almost four fold (papplication of hydrostatic pressure, in the absence of cell deformation, can bring about changes in the matrix components which may play an important role in the homeostasis and mechanical properties of articular cartilage.

  8. Linear and nonlinear optical properties of multilayered spherical quantum dots: Effects of geometrical size, hydrogenic impurity, hydrostatic pressure and temperature

    Energy Technology Data Exchange (ETDEWEB)

    Karimi, M.J. [Department of Physics, College of Sciences, Shiraz University of Technology, Shiraz 71555-313 (Iran, Islamic Republic of); Rezaei, G., E-mail: grezaei2001@gmail.com [Department of Physics, College of Sciences, Yasouj University, Yasouj 75914-353 (Iran, Islamic Republic of); Nazari, M. [Department of Physics, College of Sciences, Shiraz University of Technology, Shiraz 71555-313 (Iran, Islamic Republic of); Department of Physics, College of Sciences, Yasouj University, Yasouj 75914-353 (Iran, Islamic Republic of)

    2014-01-15

    Based on the effective mass and parabolic one band approximations, simultaneous effects of the geometrical size, hydrogenic impurity, hydrostatic pressure, and temperature on the intersubband optical absorption coefficients and refractive index changes in multilayered spherical quantum dots are studied. Energy eigenvalues and eigenvectors are calculated using the fourth-order Runge–Kutta method and optical properties are obtained using the compact density matrix approach. The results indicate that the hydrogenic impurity, hydrostatic pressure, temperature and geometrical parameters such as the well and barrier widths have a great influence on the linear, the third-order nonlinear and the total optical absorption coefficients and refractive index changes. -- Highlights: • Hydrogenic impurity effects on the optical properties of a MSQD are investigated. • Hydrostatic pressure and temperature effects are also studied. • Hydrogenic impurity has a great influence on the linear and nonlinear ACs and RICs. • Hydrostatic pressure and temperature change the linear and nonlinear ACs and RICs.

  9. Electronic structure computation and differential capacitance profile in δ-doped FET as a function of hydrostatic pressure

    Energy Technology Data Exchange (ETDEWEB)

    Carlos-Pinedo, C.; Rodríguez-Vargas, I.; Martínez-Orozco, J. C. [Unidad Académica de Física. Universidad Autónoma de Zacatecas. Calzada Solidaridad Esquina con Paseo la Bufa S/N. C.P. 98060, Zacatecas, Zac. (Mexico)

    2014-05-15

    In this work we present the results obtained from the calculation of the level structure of a n-type delta-doped well Field Effect Transistor when is subjected to hydrostatic pressure. We study the energy level structure as a function of hydrostatic pressure within the range of 0 to 6 kbar for different Schottky barrier height (SBH). We use an analytical expression for the effect of hydrostatic pressure on the SBH and the pressure dependence of the basic parameters of the system as the effective mass m(P) and the dielectric constant ε(P) of GaAs. We found that due to the effects of hydrostatic pressure, in addition to electronic level structure alteration, the profile of the differential capacitance per unit area C{sup −2} is affected.

  10. An implicit wetting and drying approach for non-hydrostatic flows in high aspect ratio domains

    CERN Document Server

    Candy, Adam S

    2013-01-01

    A wetting and drying approach for free surface flows governed by the three-dimensional, non-hydrostatic Navier-Stokes equations in high aspect ratio domains is developed. This has application in the modelling of inundation processes in geophysical domains, where dynamics takes place over a large horizontal extent relative to vertical resolution, such as in the evolution of a tsunami, or an urban fluvial flooding scenario. The approach is novel in that it solves for three dimensional dynamics in these very high aspect ratio domains, to include non-hydrostatic effects and accurately model dispersive processes. These become important in shallow regions with steep gradients, a particularly acute problem where man-made structures exist such as buildings or flood defences in an urban environment. It is implicit in time to allow efficient time integration over a range of mesh element sizes. Specific regularisation methods are introduced to improve conditioning of the full three-dimensional pressure Poisson problem i...

  11. NASTRAN structural model for the large ground antenna pedestal with applications to hydrostatic bearing of film

    Science.gov (United States)

    Chian, C. T.

    1986-01-01

    Investigations were conducted on the 64-meter antenna hydrostatic bearing oil film thickness under a variety of loads and elastic moduli. These parametric studies used a NASTRAN pedestal structural model to determine the deflections under the hydrostatic bearing pad. The deflections formed the input for a computer program to determine the hydrostratic bearing oil film thickness. For the future 64-meter to 70-meter antenna extension and for the 2.2-meter (86-in.) haunch concrete replacement cases, the program predicted safe oil film thickness (greater than 0.13 mm (0.005 in.) at the corners of the pad). The effects of varying moduli of elasticity for different sections of the pedestal and the film height under stressed runner conditions were also studied.

  12. High Hydrostatic Pressure Treatment of Porcine Oocytes before Handmade Cloning Improves Developmental Competence and Cryosurvival

    DEFF Research Database (Denmark)

    Du, Yutao; Lin, Lin; Schmidt, Mette

    2008-01-01

    An innovative technique, called the high hydrostatic pressure (HHP) treatment, has been recently reported to improve the cryosurvival of gametes or embryos in certain mammalian species. The aim of the present study was to investigate the in vitro and in vivo developmental competence and cryotoler......An innovative technique, called the high hydrostatic pressure (HHP) treatment, has been recently reported to improve the cryosurvival of gametes or embryos in certain mammalian species. The aim of the present study was to investigate the in vitro and in vivo developmental competence...... on day 5 of the estrous cycle. One recipient was diagnosed pregnant and gave birth to two healthy piglets by naturally delivery on day 122 of gestation. This pilot study proved that the sublethal HHP treatment of porcine oocytes before HMC results in improved in vitro developmental competence...

  13. The Effect of Hydrostatic Pressure and Seismic Load on ITER Lower Cryopump Ports

    Institute of Scientific and Technical Information of China (English)

    CAI Yingxiang; YU Jie; WU Songtao

    2007-01-01

    The lower cryopump ports in International Thermonuclear Experimental Reactor (ITER) as a part of the vacuum vessel play many important roles.As the boundary of vacuum it must be ensured against structural damage.In this study a finite element model of the lower cryopump ports was developed by ANSYS code with a purpose to evaluate the stress and displacement level on it. Two kinds of loads were taken into account.One was the hydrostatic pressure including the normal operation pressure and test pressure.The other was the seismic load.The analysis results show that the peak stress does not exceed the allowable stress for either the hydrostatic pressure or the seismic load according to the ITER structural design criterion,which indicates that the structure has a good safety margin.

  14. Pressure distribution in a quasi-hydrostatic pressure medium: A finite element analysis

    Science.gov (United States)

    Tempere, Jacques; Silvera, Isaac F.

    2011-12-01

    The highest quality pressures on samples in a diamond anvil cell (DAC) at high pressures are produced using quasi-hydrostatic pressurization media such as helium or hydrogen. In this paper we carry out a finite element analysis of pressure distributions in a DAC using helium and non-hydrostatic argon pressurization media. We find that samples and ruby chips are at substantially higher pressures than the pressurization media, although this is sharply reduced by using helium, which has a low yield strength for the shear modulus. The deviations in pressure of the different samples (and ruby) from the pressurization media differ and depend on their elastic constants. Our observations may account for the distribution of pressures in metallic markers found in a recent calibration of the ruby scale to high pressures.

  15. High hydrostatic pressure adaptive strategies in an obligate piezophile Pyrococcus yayanosii

    Science.gov (United States)

    Michoud, Grégoire; Jebbar, Mohamed

    2016-06-01

    Pyrococcus yayanosii CH1, as the first and only obligate piezophilic hyperthermophilic microorganism discovered to date, extends the physical and chemical limits of life on Earth. It was isolated from the Ashadze hydrothermal vent at 4,100 m depth. Multi-omics analyses were performed to study the mechanisms used by the cell to cope with high hydrostatic pressure variations. In silico analyses showed that the P. yayanosii genome is highly adapted to its harsh environment, with a loss of aromatic amino acid biosynthesis pathways and the high constitutive expression of the energy metabolism compared with other non-obligate piezophilic Pyrococcus species. Differential proteomics and transcriptomics analyses identified key hydrostatic pressure-responsive genes involved in translation, chemotaxis, energy metabolism (hydrogenases and formate metabolism) and Clustered Regularly Interspaced Short Palindromic Repeats sequences associated with Cellular apoptosis susceptibility proteins.

  16. Electrical Conductivity of Fine Crystalline Graphite under the Influence of the Hydrostatic Pressure

    Directory of Open Access Journals (Sweden)

    I.V. Ovsiienko

    2016-06-01

    Full Text Available It was investigated the influence of hydrostatic pressure on the electrical conductivity of crystalline graphite in temperature range (77-293 K. It was revealed that the reducing of electrical resistivity in specimens of fine crystalline graphite under the action of hydrostatic pressure is due to increasing of overlap between valence and conduction bands that leads to increase of the concentration of free charge carriers. The change of the overlap of valence and conduction bands was estimated. It is shown the decrease of the distance between the graphite layers under pressure is irreversible process, when load is remove the electric resistance increases slightly, but does not acquire the initial value.

  17. The Effect of Additives on The Performance of HydrostaticThrust Bearings

    Directory of Open Access Journals (Sweden)

    Muhammed Abdul Sattar

    2008-01-01

    Full Text Available The paper is concerned with, the behavior of the hydrostatic thrust bearings lubricated with liquid-solid lubricants using Einstein viscosity formula, and taking into account the centrifugal force resulting from high speed. Also studied is the effect of the bearing dimensions on the pressure, flow rate, load capacity, shear stress, power consumption and stiffness. The theoretical results show an increase in load capacity by (8.3% in the presence of solid graphite particles with concentration of (16% by weight as compared with pure oil, with increasing shear stress. . In general the performance of hydrostatic thrust bearings improve for load carrying capacity, volume flow rate, pumping power subjected to centrifugal parameter (S, recess position (r1, film thickness ratio (, particle concentration (.

  18. High hydrostatic pressure adaptive strategies in an obligate piezophile Pyrococcus yayanosii

    KAUST Repository

    Michoud, Gregoire

    2016-06-02

    Pyrococcus yayanosii CH1, as the first and only obligate piezophilic hyperthermophilic microorganism discovered to date, extends the physical and chemical limits of life on Earth. It was isolated from the Ashadze hydrothermal vent at 4,100 m depth. Multi-omics analyses were performed to study the mechanisms used by the cell to cope with high hydrostatic pressure variations. In silico analyses showed that the P. yayanosii genome is highly adapted to its harsh environment, with a loss of aromatic amino acid biosynthesis pathways and the high constitutive expression of the energy metabolism compared with other non-obligate piezophilic Pyrococcus species. Differential proteomics and transcriptomics analyses identified key hydrostatic pressure-responsive genes involved in translation, chemotaxis, energy metabolism (hydrogenases and formate metabolism) and Clustered Regularly Interspaced Short Palindromic Repeats sequences associated with Cellular apoptosis susceptibility proteins.

  19. The effects of vacancy on melting of Cu under hydrostatic and shock wave loading

    Science.gov (United States)

    Li, H.; Ni, S.

    2009-12-01

    Defects, ubiquitous in real solids, are relevant to high pressure melting under static and shock loading conditions as in the Earth’s interior and during planetary impact. A simplest type of defects is vacancy, and we investigate melt- ing of a representative metal (Cu) with pre-existing vacan- cies under hydrostatic and shock wave loading using molec- ular dynamics simulations. The equilibrium melting curve is established with the superheating-supercooling hysteresis method. During hydrostatic compression, the vacancy con- centration is reduced from its initial value and the vacancy effect on melting is minimized at high pressures. Shock wave loading is conducted along h100i at different initial vacancy concentrations. Considerable superheating occurs for initial vacancy concentration5%. Dur- ing shock loading, preexistent vacancies facilitate plasticity and other defect formation, and thus reduce melting temper- ature. Our results indicate that vacancy effect on melting should be considered for shock loading and for low hydro- static pressures. 1

  20. Partial alignment and measurement of residual dipolar couplings of proteins under high hydrostatic pressure.

    Science.gov (United States)

    Fu, Yinan; Wand, A Joshua

    2013-08-01

    High-pressure NMR spectroscopy has emerged as a complementary approach for investigating various structural and thermodynamic properties of macromolecules. Noticeably absent from the array of experimental restraints that have been employed to characterize protein structures at high hydrostatic pressure is the residual dipolar coupling, which requires the partial alignment of the macromolecule of interest. Here we examine five alignment media that are commonly used at ambient pressure for this purpose. We find that the spontaneous alignment of Pf1 phage, d(GpG) and a C12E5/n-hexnanol mixture in a magnetic field is preserved under high hydrostatic pressure. However, DMPC/DHPC bicelles and collagen gel are found to be unsuitable. Evidence is presented to demonstrate that pressure-induced structural changes can be identified using the residual dipolar coupling.

  1. Hydrostatic pressure effect on magnetic phase transition and magnetocaloric effect of metamagnetic TmZn compound

    Science.gov (United States)

    Li, Lingwei; Hu, Guanghui; Qi, Yang; Umehara, Izuru

    2017-02-01

    The magnetocaloric effect (MCE) is an intrinsic thermal response of all magnetic solids which has a direct and strong correlation with the corresponding magnetic phase transition. It has been well recognized that the magnetic phase transition can be tuned by adjusting applied pressure. Therefore, we perform the high hydrostatic pressure magnetization measurements (up to 1.4 GPa) on a recently reported giant MCE material of TmZn. The results indicate that the Curie temperature of TC increases from 8.4 K at the ambient pressure to 11.5 K under the pressure of 1.4 GPa. The field-induced first order metamagnetic transition is getting weak with increasing pressure, which results in a reduction of MCE. The hydrostatic pressure effect on the magnetic phase transition and MCE in the metamagnetic TmZn is discussed.

  2. The effect of hydrostatic vs. shock pressure treatment on plant seeds

    Science.gov (United States)

    Mustey, Adrian; Leighs, James; Appleby-Thomas, Gareth; Wood, David; Hazael, Rachael; McMillan, Paul; Hazell, Paul

    2013-06-01

    The hydrostatic pressure and shock response of plant seeds have both been previously investigated (primarily driven by an interest in reducing bacterial contamination of crops and the theory of panspermia respectively). However, comparisons have not previously been made between these two methods of applying pressure to plant seeds. Here such a comparison has been undertaken based on the premise that any correlations in such data may provide a route to inform understanding of damage mechanisms in the seeds under test. In this work two varieties of plant seeds were subjected to hydrostatic pressure via a non-end-loaded piston cylinder set-up and shock compression via employment of a 50-mm bore, single stage gas gun using the flyer-plate technique. Results from germination tests of recovered seed samples have been compared and contrasted, and initial conclusions made regarding causes of trends in the resultant data-set.

  3. Three-Dimensional Mathematical Investigation of Dynamic and Hydrostatic Pressure Distributions on Planing Hulls

    Directory of Open Access Journals (Sweden)

    Parviz Ghadimi

    2013-01-01

    Full Text Available A mathematical model is utilized in order to calculate three-dimensional pressure distributions on planing hulls. This type of modeling is able to determine the hydrodynamic and hydrostatic pressures acting on the bottom of these hulls. As a result, the total 3-dimensional pressure exerted on the planing hull as a sum of hydrostatic and hydrodynamic pressures can be evaluated. Empirical equations introduced in previous works have been used as the fundamentals for the present mathematical modeling method. The obtained results are compared against available experimental results and results of empirical equations in order to validate the proposed method. The outcome of the -squared tests conducted on these comparisons shows favorable accuracy of the results. After evaluation of hydrodynamic pressure, the effects of trim and deadrise angles and wetted length on the 3-dimensional pressure distribution are analyzed. Finally, the total pressure on planing hull and the effect of velocity coefficients are studied.

  4. Parametric analysis of thermal effect on hydrostatic slipper bearing capacity of axial piston pump

    Institute of Scientific and Technical Information of China (English)

    汤何胜; 訚耀保; 张阳; 李晶

    2016-01-01

    Hydrostatic slipper was often used in friction bearing design, allowing improvement of the latter’s dynamic behavior. The influence of thermal effect on hydrostatic slipper bearing capacity of axial piston pump was investigated. A set of lumped parameter mathematical models were developed based on energy conservation law of slipper/ swash plate pair. The results show that thermal equilibrium clearance due to solid thermal deformation periodically changes with shaft rotational angle. The slipper bearing capacity increases dramatically with decreasing thermal equilibrium clearance. In order to improve the slipper bearing capacity, length-to-diameter ratio of fixed damper varies from 3.5 to 8.75 and radius ratio of slipper varies from 1.5 to 2.0. In addition, the higher slipper thermal conductivity is useful to improve slipper bearing capability, but the thermal equilibrium clearance is not compromised.

  5. Partial alignment and measurement of residual dipolar couplings of proteins under high hydrostatic pressure

    Energy Technology Data Exchange (ETDEWEB)

    Fu, Yinan; Wand, A. Joshua, E-mail: wand@mail.med.upenn.edu [University of Pennsylvania, Department of Biochemistry and Biophysics, Johnson Research Foundation (United States)

    2013-08-15

    High-pressure NMR spectroscopy has emerged as a complementary approach for investigating various structural and thermodynamic properties of macromolecules. Noticeably absent from the array of experimental restraints that have been employed to characterize protein structures at high hydrostatic pressure is the residual dipolar coupling, which requires the partial alignment of the macromolecule of interest. Here we examine five alignment media that are commonly used at ambient pressure for this purpose. We find that the spontaneous alignment of Pf1 phage, d(GpG) and a C12E5/n-hexnanol mixture in a magnetic field is preserved under high hydrostatic pressure. However, DMPC/DHPC bicelles and collagen gel are found to be unsuitable. Evidence is presented to demonstrate that pressure-induced structural changes can be identified using the residual dipolar coupling.

  6. STABILITY OF SYSTEM OF TWO-DIMENSIONAL NON-HYDROSTATIC REVOLVING FLUIDS

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    Applying the theory of stratification, it is proved that the system of the two-dimensional non-hydrostatic revolving fluids is unstable in the two-order continuous function class. The construction of solution space is given and the solution approach is offered. The sufficient and necessary conditions of the existence of formal solutions are expressed for some typical initial and boundary value problems and the calculating formulae to formal solutions are presented in detail.

  7. Hydrostatic Compression of 2,4,6,8,10,12 hexanitrohexaaza isowurtzitane (CL20) Co Crystals

    Science.gov (United States)

    2016-12-01

    improved properties.1,2 Co-crystals are solid state materials comprising 2 (or more) molecular components that interact via noncovalent interactions...of the co-crystal’s stability to that of the individual components .6,7 However, other critical material properties such as the response of EM co...Hydrostatic Compression of 2,4,6,8,10,12- hexanitrohexaaza-isowurtzitane (CL20) Co-Crystals by DeCarlos Taylor Weapons and Materials

  8. Filtration coefficient of the axon membrane as measured with hydrostatic and osmotic methods.

    Science.gov (United States)

    Vargas, F F

    1968-01-01

    The hydraulic conductivity of the membranes surrounding the giant axon of the squid, Dosidicus gigas, was measured. In some axons the axoplasm was partially removed by suction. Perfusion was then established by insertion of a second pipette. In other axons the axoplasm was left intact and only one pipette was inserted. In both groups hydrostatic pressure was applied by means of a water column in a capillary manometer. Displacement of the meniscus in time gave the rate of fluid flowing across the axon sheath. In both groups osmotic differences across the membrane were established by the addition of a test molecule to the external medium which was seawater. The hydraulic conductivity determined by application of hydrostatic pressure was 10.6 +/- 0.8.10(-8) cm/sec cm H(2)O in perfused axons and 3.2 +/- 0.6.10(-8) cm/sec cm H(2)O in intact axons. When the driving force was an osmotic pressure gradient the conductivity was 4.5 +/- 0.6 x 10(-10) cm/sec cm H(2)O and 4.8 +/- 0.9 x 10(-10) cm/sec cm H(2)O in perfused and intact axons, respectively. A comparable result was found when the internal solution was made hyperosmotic. The fluid flow was a linear function of the hydrostatic pressure up to 70 cm of water. Glycerol outflux and membrane conductance were increased 1.6 and 1.1 times by the application of hydrostatic pressure. These increments do not give an explanation of the difference between the filtration coefficients. Other possible explanations are suggested and discussed.

  9. Research on the properties of a hydrostatic transmission for different efficiency models of its elements

    Directory of Open Access Journals (Sweden)

    Stojek Jerzy

    1997-12-01

    Full Text Available The article presents some considerations on the effect of the assumed mathematical models of the pump efficiency and the hydraulic engine, exerted upon the static and dynamic properties of a hydrostatic transmission. For this purpose some simulation tests of the transmission described have been carried out with two models: one - simplified, containing efficiency constants, and the other - an extended one with various efficiency values.

  10. Synthetic observations of first hydrostatic cores in collapsing low-mass dense cores. I. Spectral energy distributions and evolutionary sequence

    OpenAIRE

    Commercon, Benoit; Launhardt, Ralf; Dullemond, Cornelis P.; Henning, Thomas

    2012-01-01

    The low-mass star formation evolutionary sequence is relatively well-defined both from observations and theoretical considerations. The first hydrostatic core is the first protostellar equilibrium object that is formed during the star formation process. Using state-of-the-art radiation-magneto-hydrodynamic 3D adaptive mesh refinement calculations, we aim to provide predictions for the dust continuum emission from first hydrostatic cores. We investigate the collapse and the fragmentation of ma...

  11. 超精密静压支承部件及其在超精密加工机床的应用%Ultra Precision Hydrostatic Bearing Components and Its Application in Ultra Precision Machine Tools

    Institute of Scientific and Technical Information of China (English)

    胡秋; 夏仰球; 米良; 李梦阳

    2015-01-01

    Ultra precision machining technique and equipment have developed greatly in recent years. Ultra precision hydrostatic bearing component is a key common component of ultra-precision processing equipment. The structure characteristics, technical proper-ties and application situation of hydrostatic/aerostatic bearing spindle, guide-way and rotary table were introduced roundly. A typical ul-tra-precision machine tool was taken as an example to present the application of the ultra precision hydrostatic/aerostatic bearing spin-dle, guide-way and rotary table.%超精密加工技术与装备在近年得到极大发展. 超精密静压部件是超精密加工装备关键共性部件. 以平面气体静压支承为例, 介绍了静压支承基本工作原理. 对超精密液体/气体静压主轴、 导轨和转台的结构特点、 技术特性、 应用场合作了较全面的介绍; 以典型超精密加工机床为例, 介绍静精密静压主轴、 导轨和转台在超精密加工机床中的应用.

  12. The Design of Hydrostatic Guide-way Used for High-speed Rotary Table%高速回转工作台静压导轨的设计

    Institute of Scientific and Technical Information of China (English)

    贾文明

    2014-01-01

    静压导轨具有工作寿命长、摩擦系数低、速度和载荷变化对油膜刚度影响小,工作性能稳定等优点。但在实际应用中高速静压导轨受到了很大限制,由于转速的提高造成系统发热量和油温升高,导致导轨及工作台热变形严重,机床工作稳定性不好等问题。针对以上问题,对一种高速回转工作台所用静压导轨进行了结构设计与相应计算。%Hydrostatic guide-way has the characteristics of low coefficient of friction, speed and loading variety to the oil film rigidity influence small, the working ability stabilized. But at application in high-speed hydrostatic guide-way is very greatly limited and result in the system has fever quantity and oil temperature to heat up and lead the guide-way and table thermal deformation because of the rotary speed up, and the machine tool works stability not very well. Therefore, the calculation and structure design of hydrostatic floating guideway are carried out in this paper.

  13. 新型动静压混合润滑机械密封流场数值研究%Numerical Study on Flow Field of New-type Hydrostatic-dynamic Hybrid Lubrication Seal

    Institute of Scientific and Technical Information of China (English)

    王彬; 郝木明

    2009-01-01

    A three-dimensional model of the new-type hydrostatic-dynamic hybrid lubrication seals was developed based on fluid film. The pressure and velocity distribution of fluid film was simulated by using the software of computational fluid dynamics. The law of influence of operating parameters (sealant pressure, rotating speed) on sealing performance was ana-lyzed by comparing with hydrostatic seals and dynamic seals. The results show that this type of seal has the characteristics of hydrostatic seals and dynamic seals, it has low leakage and high film stiffness, and is suitable for low speed non-contac-ting seals.%以流体膜为研究对象,建立了新型动静压混合润滑密封端面的三维模型,并利用流体力学软件FLUENT对端面流场进行数值模拟,得出端面液膜的压力分布及速度分布.通过与静压和动压式密封对比,分析了操作参数(如封液压力、转速)对密封性能的影响规律.结果表明,该密封兼有动压与静压两种密封形式的特点,泄漏量小,液膜刚度大,适合于低速非接触密封.

  14. Velocity control of a secondary controlled closed-loop hydrostatic transmission system using an adaptive fuzzy sliding mode controller

    Energy Technology Data Exchange (ETDEWEB)

    Do, Hoang Thinh; Ahn, Kyoung Kwan [University of Ulsan, Ulsan (Korea, Republic of)

    2013-03-15

    A secondary-controlled hydrostatic transmission system (SC-HST), which considered being an energy-saving system, can recuperate most of the lost vehicle kinetic energy in decelerating and braking time and it shows advantage in fuel economy improvement of vehicle. Almost secondary control units (SCU) in SC-HST inherently contain nonlinear characteristics such as dead-zone input. Therefore, it is difficult to obtain precise position or velocity control by conventional linear controllers. This problem limits the application of SC-HST in industry and mobile vehicle. This paper gives a description of SC-HST and proposes an adaptive fuzzy sliding mode controller (AFSMC) for velocity control of SCU. Experiments were carried out in the condition of disturbance load by using both the proposed controller and PID controller for the comparison and evaluation of the effectiveness of the proposed controller. The experimental results showed that the proposed controller was excellent from the standpoints of performance and stability for the velocity control of SC-HST.

  15. Linear and nonlinear properties of reduced two-layer models for non-hydrostatic free-surface flow

    Science.gov (United States)

    Bai, Yefei; Cheung, Kwok Fai

    2016-11-01

    A two-layer model with uniform non-hydrostatic pressure in the bottom produces favorable dispersion properties for coastal wave transformation at the computational requirements of a one-layer model. We derive the nonlinear governing equations and the corresponding dispersion relation, shoaling gradient, and super- and sub-harmonics to understand the theoretical performance of this reduced model. With the layer interface near the bottom, the dispersion relation shows an extended applicable range into deeper water at the expense of a slight overestimation of the celerity in intermediate water depth. The shoaling gradient rapidly converges to the exact solution in the shallow and intermediate depth range. These complementary characteristics allow identification of an optimal interface position for both linear wave properties. The resulting model exhibits good nonlinear performance in shallow and intermediate water depth and produces super- and sub-harmonics comparable to a two-layer model. Numerical tests involving standing waves show the reduced model has smaller discretization errors in the dispersion relation comparing to a one-layer model. Case studies of regular wave transformation over a submerged bar and a uniform slope provide comparison with laboratory data and demonstrate the linear and nonlinear properties derived from the governing equations. The good shoaling and nonlinear properties give rise to accurate waveforms in both cases, while dispersion errors from the governing equations and numerical schemes accumulate over time leading to phase shifts of the modeled waves.

  16. Modelling free surface flow with curvilinear streamlines by a non-hydrostatic model

    Directory of Open Access Journals (Sweden)

    Zerihun Yebegaeshet T.

    2016-09-01

    Full Text Available This study addresses a particular phenomenon in open channel flows for which the basic assumption of hydrostatic pressure distribution is essentially invalid, and expands previous suggestions to flows where streamline curvature is significant. The proposed model incorporates the effects of the vertical curvature of the streamline and steep slope, in making the pressure distribution non-hydrostatic, and overcomes the accuracy problem of the Saint-Venant equations when simulating curvilinear free surface flow problems. Furthermore, the model is demonstrated to be a higher-order one-dimensional model that includes terms accounting for wave-like variations of the free surface on a constant slope channel. Test results of predicted flow surface and pressure profiles for flow in a channel transition from mild to steep slopes, transcritical flow over a short-crested weir and flow with dual free surfaces are compared with experimental data and previous numerical results. A good agreement is attained between the experimental and computed results. The overall simulation results reveal the satisfactory performance of the proposed model in simulating rapidly varied gravity-driven flows with predominant non-hydrostatic pressure distribution effects. This study suggests that a higher-order pressure equation should be used for modelling the pressure distribution of a curvilinear flow in a steeply sloping channel.

  17. A 3D unstructured non-hydrostatic ocean model for internal waves

    Science.gov (United States)

    Ai, Congfang; Ding, Weiye

    2016-10-01

    A 3D non-hydrostatic model is developed to compute internal waves. A novel grid arrangement is incorporated in the model. This not only ensures the homogenous Dirichlet boundary condition for the non-hydrostatic pressure can be precisely and easily imposed but also renders the model relatively simple in its discretized form. The Perot scheme is employed to discretize horizontal advection terms in the horizontal momentum equations, which is based on staggered grids and has the conservative property. Based on previous water wave models, the main works of the present paper are to (1) utilize a semi-implicit, fractional step algorithm to solve the Navier-Stokes equations (NSE); (2) develop a second-order flux-limiter method satisfying the max-min property; (3) incorporate a density equation, which is solved by a high-resolution finite volume method ensuring mass conservation and max-min property based on a vertical boundary-fitted coordinate system; and (4) validate the developed model by using four tests including two internal seiche waves, lock-exchange flow, and internal solitary wave breaking. Comparisons of numerical results with analytical solutions or experimental data or other model results show reasonably good agreement, demonstrating the model's capability to resolve internal waves relating to complex non-hydrostatic phenomena.

  18. Compressive Strength of Hydrostatic-Stress-Sensitive Materials at High Strain-Rates

    Institute of Scientific and Technical Information of China (English)

    LI Q M; LU Y B

    2008-01-01

    Many engineering materials demonstrate dynamic enhancement of their compressive strength with the increase of strain-rate.which have been included in material models to improve the reliability of numerical Simulations of the material and structural responses Under impact and biasl tcads,The strain-rate effects on the dynamic Compressive strength of a range of engineering materials which behave in hydrostatic-stress-sensitive manner were investigated.It is concluded that the dynamic enhancement of the compressive strength of a hydrostatic-stress-sensitive material may include inertia-induced lateral confinement effects,which,as a non-strain-rate factor,may greatly enhance the compressive strength of these materials.Some empirical formulae based on the dynamic stress-strain measurements over-predict the strain-rate effects on the compressive strength of these hydrostatic-stress-sensitive materials,and thus may over-estimate the structural resistance to impact and blast lgads.leading fo non-conservative design of protective structures.

  19. Hydrodynamic and hydrostatic modelling of hydraulic journal bearings considering small displacement condition

    Science.gov (United States)

    Chen, Chi-Yin; Chuang, Jen-Chen; Tu, Jia-Ying

    2016-09-01

    This paper proposes modified coefficients for the dynamic model of hydraulic journal bearing system that integrates the hydrodynamic and hydrostatic properties. In recent years, design of hydraulic bearing for machine tool attracts worldwide attention, because hydraulic bearings are able to provide higher capacity and accuracy with lower friction, compared to conventional bearing systems. In order to achieve active control of the flow pressure and enhance the operation accuracy, the dynamic model of hydraulic bearings need to be developed. Modified coefficients of hydrostatic stiffness, hydrodynamic stiffness, and squeeze damping of the dynamic model are presented in this work, which are derived referring to small displacement analysis from literature. The proposed modified coefficients and model, which consider the pressure variations, relevant geometry size, and fluid properties of the journal bearings, are able to characterise the hydrodynamic and hydrostatic properties with better precision, thus offering the following pragmatic contribution: (1) on-line prediction of the eccentricity and the position of the shaft in the face of external force that results in vibration; (2) development of active control system to regulate the supply flow pressure and to minimize the eccentricity of the shaft. Theoretical derivation and simulation results with different vibration cases are discussed to verify the proposed techniques.

  20. Numerical estimation of various influence factors on a multipoint hydrostatic leveling system

    Science.gov (United States)

    Tsvetkov, R. V.; Yepin, V. V.; Shestakov, A. P.

    2017-06-01

    Among various methods that allow controlling quasi-static vertical displacements of structures, the hydrostatic leveling method remains relevant. A multi-point hydrostatic leveling systems allows controlling the vertical displacement field with the required spatial resolution. It is assumed that the liquid level in the each measuring vessel has the same absolute elevation. However, it is influenced by various external factors, which are difficult to eliminate when implementing the method in real constructions. Consequently, it is necessary to assess the influence of these factors and develop methods aimed at their reduction or compensation. A mathematical model, describing the viscous incompressible fluid motion located in a multipoint level with absolutely rigid walls, is presented in the paper. The experiments performed with two point levels of different lengths, as well as analytical estimates of other authors, made it possible to estimate the degree of confidence of the model and the boundaries of applicability. The influence of non-uniform density of a liquid on the liquid level in a 4-point hydrostatic level of different topologies is numerically estimated using the model. An estimation of transient processes in the level, caused by an air pressure surge over one of the measuring vessels is carried out.

  1. Pressure Decimation and Interpolation (PDI) method for a baroclinic non-hydrostatic model

    Science.gov (United States)

    Shi, Jian; Shi, Fengyan; Kirby, James T.; Ma, Gangfeng; Wu, Guoxiang; Tong, Chaofeng; Zheng, Jinhai

    2015-12-01

    Non-hydrostatic models are computationally expensive in simulating density flows and mass transport problems due to the requirement of sufficient grid resolution to resolve density and flow structures. Numerical tests based on the Non-Hydrostatic Wave Model, NHWAVE (Ma et al., 2012), indicated that up to 70% of the total computational cost may be born by the pressure Poisson solver in cases with high grid resolution in both vertical and horizontal directions. However, recent studies using Poisson solver-based non-hydrostatic models have shown that an accurate prediction of wave dispersion does not require a large number of vertical layers if the dynamic pressure is properly discretized. In this study, we explore the possibility that the solution for the dynamic pressure field may, in general, be decimated to a resolution far coarser than that used in representing velocities and other transported quantities, without sacrificing accuracy of solutions. Following van Reeuwijk (2002), we determine the dynamic pressure field by solving the Poisson equation on a coarser grid and then interpolate the pressure field onto a finer grid used for solving for the remaining dynamic variables. With the Pressure Decimation and Interpolation (PDI) method, computational efficiency is greatly improved. We use three test cases to demonstrate the model's accuracy and efficiency in modeling density flows.

  2. A novel technique towards deployment of hydrostatic pressure based level sensor in nuclear fuel reprocessing facility.

    Science.gov (United States)

    Praveen, K; Rajiniganth, M P; Arun, A D; Sahoo, P; Murty, S A V Satya

    2016-02-01

    A novel approach towards deployment of a hydrostatic pressure based level monitoring device is presented for continuous monitoring of liquid level in a reservoir with high resolution and precision. Some of the major drawbacks such as spurious information of measured level due to change in ambient temperature, requirement of high resolution pressure sensor, and bubbling effect by passing air or any gaseous fluid into the liquid are overcome by using such a newly designed hydrostatic pressure based level monitoring device. The technique involves precise measurement of hydrostatic pressure exerted by the process liquid using a high sensitive pulsating-type differential pressure sensor (capacitive type differential pressure sensor using a specially designed oil manometer) and correlating it to the liquid level. In order to avoid strong influence of temperature on liquid level, a temperature compensation methodology is derived and used in the system. A wireless data acquisition feature has also been provided in the level monitoring device in order to work in a remote area such as a radioactive environment. At the outset, a prototype level measurement system for a 1 m tank is constructed and its test performance has been well studied. The precision, accuracy, resolution, uncertainty, sensitivity, and response time of the prototype level measurement system are found to be less than 1.1 mm in the entire range, 1%, 3 mm, <1%, 10 Hz/mm, and ∼4 s, respectively.

  3. Artificial induction of mito-gynogenetic diploids in large yellow croaker ( Pseudosciaena crocea) by hydrostatic pressure

    Science.gov (United States)

    Cai, Mingyi; Wu, Qingming; Liu, Xiande; Yao, Cuiluan; Chen, Qingkai; Wang, Zhiyong

    2010-07-01

    The present study investigated conditions for inducing mito-gynogenetic (endomitosis) diploids by hydrostatic pressure in the large yellow croaker Pseudosciaena crocea. In haploid control groups, the development of eggs was activated with ultraviolet radiated semen. All fry presented typical haploid syndrome in the haploid control groups, and were verified as haploids using cytometry. After hydrostatic pressure treatment, morphologically normal fry reappeared at different frequencies according to the intensity and time of pressure shock. Fry with normal appearance in the pressure treated groups were verified as gynogenetic double haploids (GDHs), containing only one allele from the female parent at all four diagnostic microsatellite loci. For a fixed duration of 3 min, the optimal intensity of blocking the first mitosis was determined to be 40 Mpa, which was similar to that of blocking the second meiosis. There was a “window” of starting time, from 36.1 min to 38.1 min post-insemination at 25.0±1.0°C, within which the production of GDHs was not significantly different. Maximum production of morphologically normal fries, 9.36%±2.97% of developed eggs, was found when the eggs were shocked with hydrostatic pressure at 40 Mpa for 3 min, starting from 38.1 min post insemination at 25.0±1.0°C.

  4. Pollution Analysis of New Synthetic Biodegradable Fluid During Durab Ility Test of Hydrostatic Pump

    Directory of Open Access Journals (Sweden)

    Tulík Juraj

    2014-03-01

    Full Text Available This paper deals with the pollution evaluation of a biodegradable fluid, which was used as a working medium during the laboratory durability test of a hydrostatic pump. There was used a new synthetic biodegradable fluid MOL Farm UTTO Synt., developed and produced by MOL Group, Hungary. The fluid should have been practically used as a universal, common gear-hydraulic filling in agricultural machines. During the test, the pollution of used fluid was evaluated on the basis of cleanliness code, filtration of solid particles and ferrography. Based on results of cleanliness code, we could monitor the course of hydrostatic pump wear. After test completion, the fluid was subjected to filtration of solid particles and ferrography, where clusters of small particles and larger particles were detected. On the basis of their surface and shape, they were included in particles of adhesive wear. By the comparison method it was found that they are bronze particles located in the bearings of the hydrostatic pump used.

  5. Research on the properties of a hydrostatic transmission with different controllers

    Directory of Open Access Journals (Sweden)

    Piotrowska Agata

    2003-12-01

    Full Text Available In this paper the possibility of a uses control system with a signal processor DSP to control hydrostatic transmission was described. A hydrostatic transmission with pump variable efficiency and engine radial with constant working absorptivity was chosen. The control of the efficiency of pump was realized by using the electrohydraulic control system. This hydraulic system consists of a servo-cylinder and electrohydraulic servovalve. Such an object is one of the most important parts of working machines. Because the object is nonlinear and not time invariant its control is very difficult. In the last few years using the signal processor DSP for control has become very popular. In this paper the use of cascade controllers in DSP was described. The cascade controllers realize control of the position of the servo-cylinder and the control of the rotational speed of the hydraulic engine To chose the controller’s parameters the simulation model adopted in Matlab/Simulink was used. The object used parameters from simulation tests. Many different tests were conducted on a laboratory hydrostatic transmission.

  6. ACTIVE CONTROL OF THE PIEZOELASTIC LAMINATED CYLINDRICAL SHELL'S VIBRATION UNDER HYDROSTATIC PRESSURE

    Institute of Scientific and Technical Information of China (English)

    李红云; 林启荣; 刘正兴; 王超

    2003-01-01

    The control of the piezoelastic laminated cylindrical shell's vibration under hydrostatic pressure was discussed. From Hamilton's principle nonlinear dynamic equations of the piezoelastic laminated cylindrical shell were derived. Based on which, the dynamic equations of a closed piezoelastic cylindrical shell under hydrostatic pressure are obtained. An analytical solution was presented for the case of vibration of a simply supported piezoelastic laminated cylindrical shell under hydrostatic pressure. Using veloctity feedback control, a model for active vibration control of the laminated cylindrical shell with piezoelastic sensor/ actuator is established. Numerical results show that, the static deflection of the cylindrical shell can be changed when voltages with suitable value and direction are applied on the piezoelectric layers. For the dynamic response problem of the system, the larger the gain is, the more the vibration of the system is suppressed in the vicinity of the resonant zone. This presents a potential way to actively reduce the harmful effect of the resonance on the system and verify the feasibility of the active vibration control model.

  7. Hydrostatic Parameters and Domain Effects in Novel 2-2 Composites Based on PZN-0.12PT Single Crystals

    Directory of Open Access Journals (Sweden)

    Vitaly Yu. Topolov

    2011-01-01

    Full Text Available A novel 0.88Pb(Zn1/3Nb2/3O3-0.12PbTiO3 crystal/polymer composite with 2-2 connectivity is studied at variable orientations of spontaneous polarisation vector of the crystal component. Orientation and volume-fraction dependences of the hydrostatic piezoelectric coefficients dh*, eh*, and gh* and hydrostatic electromechanical coupling factor kh* are related to the important role of the piezoelectric and elastic anisotropy of single-domain layers of the 2-2 composite. The record value of |eh∗|≈77 C/m2 near the absolute-minimum point and the correlation between the hydrostatic (eh* and piezoelectric (e3j* coefficients and between the hydrostatic (gh* and piezoelectric (g3j* coefficients are first established. This discovery is of value for hydrostatic and piezotechnical applications. The hydrostatic performance of the composite based on the single-domain 0.88Pb(Zn1/3Nb2/3O3-0.12PbTiO3 crystal is compared to the performance of the 2–2 composites based on either the same polydomain crystal or the related single-domain crystal.

  8. Numerical modelling of the flow in the annular multi-recess hydrostatic thrust bearing using CFD methods

    Directory of Open Access Journals (Sweden)

    Drbáková S.

    2013-04-01

    Full Text Available The current research of hydrostatic bearings and hydrostatic slide-ways is far from being over. The topic is constantly evolving, creating new geometries of the sliding bearings, developing new types of friction materials and lubricants. The control elements of hydraulic mechanisms that serve to regulation of the hydrostatic bearings tipping are still in progress. Almost every application has different requirements for the bearings, whether in terms of loading capacity, speed rotation, and also the price. All these aspects should be included in the design of hydrostatic thrust bearings. Thanks to great advances in the development of computer technology and software for numerical modelling, we can simulate real movement of viscous fluids. To create a numerical model of hydrostatic thrust bearing, Ansys Fluent 14.0 software package has been applied. The article describes the basic methods of numerical modelling of the given problem and evaluates the pressure field and the loading capacity of annular multi-recess hydrostatic thrust bearing and its dependence on the change in static pressure.

  9. Two-row inner-restrictor hydrostatic bearing without oil-back curve%无回油槽双列内节流液体静压轴承的研究

    Institute of Scientific and Technical Information of China (English)

    王瑜; 王涛; 马玉林

    2000-01-01

    The structure of inner-restrictor hydrostatic bearing is easy to guarantee precision of restrictor. Two-row inner-restrictor hydrostatic bearing features simple and compact structure, little leakage of lubricating oil, low power consumption and small deflection of bearing axle. And, it is therefore necessary to study all the characteristics of this kind of bearings. Following to hydrostatic bearing theory and using flow quantity balance equations, the basic charactersistics of two-row inner-restrictor hydrostatic bearing without oil-back curve, including radial load bearing ability and bending load bearing ability are analysed to provide theoretical basis for its future application%内节流液体静压轴承结构简单、紧凑、容易保证节流精度,而且双列内节流静压轴承润滑油泄漏少,功耗小,轴的挠曲刚度高,因此有必要对这种轴承的性能进行全面的研究,根据液体静压支承理论,利用流量平衡方程,分析了无回油槽双列内节流液体静压轴承的基本性能,即承受径向载荷和承受弯矩的能力,得出了一些重要结论,从而为该轴承在实际中应用提供了理论依据

  10. Structural Phase Transition in CdSb + 3 % MnSb Composite at a High Hydrostatic Pressure

    Directory of Open Access Journals (Sweden)

    R.G. Dzhamamedov

    2015-12-01

    Full Text Available In CdSb + 3 % MnSb composite, structural properties have been studied, specific resistance ρ and Hall coefficient RH are measured at a high hydrostatic pressure of up to P ≤ 9 GPa. An irreversible structural phase transition is found at barometric dependencies p(P and RH(P. From our experimental data, barometric dependencies of carrier concentration and their mobility are calculated. On the basis of the heterophase structure – effective medium model, characteristic points and parameters of the phase transition, and also dynamics of variation of the initial phase volume C1 as a function of pressure are computed. The latter dependence is in agreement with the investigation results of Raman scattering before and after application of pressure.

  11. The effect of hydrostatic pressure and uniaxial strain on the electronic structure of Pb$_{\\text{1-x}}$Sn$_{\\text{x}}$Te

    CERN Document Server

    Geilhufe, Matthias; Thomas, Stefan; Däne, Markus; Tripathi, Gouri S; Entel, Peter; Hergert, Wolfram; Ernst, Arthur

    2015-01-01

    The electronic structure of Pb$_{1-x}$Sn$_{x}$Te is studied by using the relativistic Korringa-Kohn-Rostoker Green function method in the framework of density functional theory. For all concentrations $x$, Pb$_{1-x}$Sn$_{x}$Te is a direct semiconductor with a narrow band gap. In contrast to pure lead telluride, tin telluride shows an inverted band characteristic close to the Fermi energy. It will be shown that this particular property can be tuned, first, by alloying PbTe and SnTe and, second, by applying hydrostatic pressure or uniaxial strain. Furthermore, the magnitude of strain needed to switch between the regular and inverted band gap can be tuned by the alloy composition. Thus, there is range of potential usage of Pb$_{1-x}$Sn$_{x}$Te for spintronic applications.

  12. A preliminary study about the influence of high hydrostatic pressure processing in parallel with oak chip maceration on the physicochemical and sensory properties of a young red wine.

    Science.gov (United States)

    Tao, Yang; Sun, Da-Wen; Górecki, Adrian; Błaszczak, Wioletta; Lamparski, Grzegorz; Amarowicz, Ryszard; Fornal, Józef; Jeliński, Tomasz

    2016-03-01

    The influence of high hydrostatic pressure (HHP) processing in parallel with oak chip maceration on the physicochemical and sensory properties of a young red wine was investigated preliminarily. Wines were treated by HHP at 250, 450 and 650MPa for up to 45min and French oak chips (5g/L) were added. HHP enhanced the extraction of phenolics from oak chips. The phenolic contents and antioxidant activity of the wine increased after HHP processing in the presence of oak chips. Meanwhile, the anthocyanin content and wine color intensity decreased in the first 5min of pressure treatment and then increased gradually. The multivariate analysis revealed that "pressure holding time" was the key factor affecting wine physicochemical characteristics during HHP processing in the presence of oak chips. Furthermore, oak chip maceration with and without HHP processing weakened the intensities of several sensory attributes and provided the wine with an artificial taste.

  13. The role of ontogeny in physiological tolerance: decreasing hydrostatic pressure tolerance with development in the northern stone crab Lithodes maja.

    Science.gov (United States)

    Munro, Catriona; Morris, James P; Brown, Alastair; Hauton, Chris; Thatje, Sven

    2015-06-22

    Extant deep-sea invertebrate fauna represent both ancient and recent invasions from shallow-water habitats. Hydrostatic pressure may present a significant physiological challenge to organisms seeking to colonize deeper waters or migrate ontogenetically. Pressure may be a key factor contributing to bottlenecks in the radiation of taxa and potentially drive speciation. Here, we assess shifts in the tolerance of hydrostatic pressure through early ontogeny of the northern stone crab Lithodes maja, which occupies a depth range of 4-790 m in the North Atlantic. The zoea I, megalopa and crab I stages were exposed to hydrostatic pressures up to 30.0 MPa (equivalent of 3000 m depth), and the relative fold change of genes putatively coding for the N-methyl-D-aspartate receptor-regulated protein 1 (narg gene), two heat-shock protein 70 kDa (HSP70) isoforms and mitochondrial Citrate Synthase (CS gene) were measured. This study finds a significant increase in the relative expression of the CS and hsp70a genes with increased hydrostatic pressure in the zoea I stage, and an increase in the relative expression of all genes with increased hydrostatic pressure in the megalopa and crab I stages. Transcriptional responses are corroborated by patterns in respiratory rates in response to hydrostatic pressure in all stages. These results suggest a decrease in the acute high-pressure tolerance limit as ontogeny advances, as reflected by a shift in the hydrostatic pressure at which significant differences are observed. © 2015 The Author(s) Published by the Royal Society. All rights reserved.

  14. Synthetic observations of first hydrostatic cores in collapsing low-mass dense cores. I. Spectral energy distributions and evolutionary sequence

    Science.gov (United States)

    Commerçon, B.; Launhardt, R.; Dullemond, C.; Henning, Th.

    2012-09-01

    Context. The low-mass star formation evolutionary sequence is relatively well-defined both from observations and theoretical considerations. The first hydrostatic core is the first protostellar equilibrium object that is formed during the star formation process. Aims: Using state-of-the-art radiation-magneto-hydrodynamic 3D adaptive mesh refinement calculations, we aim to provide predictions for the dust continuum emission from first hydrostatic cores. Methods: We investigated the collapse and the fragmentation of magnetized 1 M⊙ prestellar dense cores and the formation and evolution of first hydrostatic cores using the RAMSES code. We used three different magnetization levels for the initial conditions, which cover a wide variety of early evolutionary morphology, e.g., the formation of a disk or a pseudo-disk, outflow launching, and fragmentation. We post-processed the dynamical calculations using the 3D radiative transfer code RADMC-3D. We computed spectral energy distributions and usual evolutionary stage indicators such as bolometric luminosity and temperature. Results: We find that the first hydrostatic core lifetimes depend strongly on the initial magnetization level of the parent dense core. We derive, for the first time, spectral energy distribution evolutionary sequences from high-resolution radiation-magneto-hydrodynamic calculations. We show that under certain conditions, first hydrostatic cores can be identified from dust continuum emission at 24 μm and 70 μm. We also show that single spectral energy distributions cannot help in distinguishing between the formation scenarios of the first hydrostatic core, i.e., between the magnetized and non-magnetized models. Conclusions: Spectral energy distributions are a first useful and direct way to target first hydrostatic core candidates but high-resolution interferometry is definitively needed to determine the evolutionary stage of the observed sources.

  15. Effect of the working liquid compressibility on the picture of volumetric and mechanical losses in a high pressure displacement pump used in a hydrostatic drive

    National Research Council Canada - National Science Library

    Paszota, Zygmunt

    2012-01-01

    Working liquid compressibility may considerably change the values and proportions of coefficients of volumetric and mechanical energy losses in the displacement pump used in a hydrostatic drive system...

  16. Efficient non-hydrostatic modelling of 3D wave-induced currents using a subgrid approach

    Science.gov (United States)

    Rijnsdorp, Dirk P.; Smit, Pieter B.; Zijlema, Marcel; Reniers, Ad J. H. M.

    2017-08-01

    Wave-induced currents are an ubiquitous feature in coastal waters that can spread material over the surf zone and the inner shelf. These currents are typically under resolved in non-hydrostatic wave-flow models due to computational constraints. Specifically, the low vertical resolutions adequate to describe the wave dynamics - and required to feasibly compute at the scales of a field site - are too coarse to account for the relevant details of the three-dimensional (3D) flow field. To describe the relevant dynamics of both wave and currents, while retaining a model framework that can be applied at field scales, we propose a two grid approach to solve the governing equations. With this approach, the vertical accelerations and non-hydrostatic pressures are resolved on a relatively coarse vertical grid (which is sufficient to accurately resolve the wave dynamics), whereas the horizontal velocities and turbulent stresses are resolved on a much finer subgrid (of which the resolution is dictated by the vertical scale of the mean flows). This approach ensures that the discrete pressure Poisson equation - the solution of which dominates the computational effort - is evaluated on the coarse grid scale, thereby greatly improving efficiency, while providing a fine vertical resolution to resolve the vertical variation of the mean flow. This work presents the general methodology, and discusses the numerical implementation in the SWASH wave-flow model. Model predictions are compared with observations of three flume experiments to demonstrate that the subgrid approach captures both the nearshore evolution of the waves, and the wave-induced flows like the undertow profile and longshore current. The accuracy of the subgrid predictions is comparable to fully resolved 3D simulations - but at much reduced computational costs. The findings of this work thereby demonstrate that the subgrid approach has the potential to make 3D non-hydrostatic simulations feasible at the scale of a

  17. Hydrostatic pressure cells development for X-ray and neutrons experiments

    Energy Technology Data Exchange (ETDEWEB)

    Passamai Junior, Jose Luis; Pinheiro, Christiano J.G.; Orlando, Marcos Tadeu D.; Passos, Carlos A.C. [Universidade Federal do Espirito Santo (UFES), Vitoria, ES (Brazil). Dept. de Fisica; Correa, Hamilton P.S. [Universidade Federal do Mato Grosso do Sul (UFMS), Campo Grande, MS (Brazil); Rossi, Jesualdo L.; Mazzocchi, Vera L.; Parente, Carlos B.R.; Mestnik Filho, Jose; Martinez, Luis G., E-mail: jelrossi@ipen.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil); Melo, Francisco C.L. de, E-mail: frapi@iae.cta.br [Centro Tecnologico da Aeronautica (CTA), Sao Jose dos Campos, SP (Brazil). Dept. de Ciencia e Tecnologia Aeroespacial

    2011-07-01

    A set of hydrostatic pressure cells was specially developed in order to be applied in X-ray diffraction, X-ray absorption and neutron diffraction experiments. For the experiments where X-rays are used, the pressure cells are built in a CuBe alloy body with two B{sub 4}C anvils in order to allow the low absorption of the radiation. The B{sub 4}C anvils were specially prepared in CTA - Centro Tecnico Aeroespacial - Sao Jose dos Campos - Brazil, in order to present enhanced X-ray transparency and high hardness. One of the advantage of the CuBe-body cell with B{sub 4}C anvil is that it can be also used under magnetic fields, for instance for measurements of AC magnetic susceptibility under high hydrostatic pressures. The X-ray cells work in transmission mode and present a 2 mm diameter hole for the beam path. The X-ray beam pass through the hole and outgoing to the detector positioned in front of the pressure cell. A second type of pressure cell was developed in order to be used in neutron elastic scattering experiments, especially in neutron diffraction experiments. The neutron cell pressure cell was constructed in Zirconium alloy reinforced with carbon fibers composite in order to improve the mechanical resistance of his cylindrical geometry. The B{sub 4}C pressure cells are available to users of the techniques of X-ray diffraction and absorption in the Brazilian National Synchrotron Laboratory - LNLS, at Campinas City. The neutron pressure cell is available to users at the neutron powder diffraction facility installed at the Nuclear and Energy Research Institute - IPEN, Sao Paulo. In this work will be shown details and drawings of the two types of hydrostatic pressure cells. (author)

  18. Hydrostatic pressure and temperature effects on nonlinear optical rectification in a lens shape InAs/GaAs quantum dot

    Energy Technology Data Exchange (ETDEWEB)

    Bouzaieene, L., E-mail: lotfi.bouzaiene@fsm.rnu.tn [Laboratoire de Micro-optoelectronique et Nanostructures, Departement de Physique, Faculte des Sciences de Monastir, Universite de Monastir (Tunisia); Ben Mahrsia, R.; Baira, M.; Sfaxi, L.; Maaref, H. [Laboratoire de Micro-optoelectronique et Nanostructures, Departement de Physique, Faculte des Sciences de Monastir, Universite de Monastir (Tunisia)

    2013-03-15

    We have performed theoretical calculation of the nonlinear optical rectification in a lens shape InAs/GaAs quantum dot (0D). The combined effects of hydrostatic pressure and temperature on the nonlinear optical rectification in lens-shaped InAs QDs are studied under the compact density matrix formalism and the effective mass approximation. From our calculation, it is found that the subband energies and optical rectification susceptibility are quite sensitive to the applied hydrostatic pressure and temperature. The results show that the resonant peak of the optical rectification can be red-shifted or blue-shifted and their intensity also varied by external probes such as hydrostatic pressure and temperature. In addition, the oscillator strength is strongly affected by these parameters. - Highlights: Black-Right-Pointing-Pointer Theoretical calculation of the nonlinear optical rectification in a lens shape InAs/GaAs quantum dot was performed. Black-Right-Pointing-Pointer Optical rectification susceptibility is quite sensitive to the applied hydrostatic pressure and temperature. Black-Right-Pointing-Pointer The oscillator strength is strongly affected by the applied hydrostatic pressure and temperature.

  19. Monitoring of pipeline hydrostatic testing with artificial flaws applying acoustic emission and ultra-sonic techniques; Monitoracao de teste hidrostatico de tubos com descontinuidades artificiais empregando as tecnicas de emissao acustica e ultra-som

    Energy Technology Data Exchange (ETDEWEB)

    Soares, Sergio Damasceno [PETROBRAS, Rio de Janeiro, RJ (Brazil). Centro de Pesquisas (CENPES)

    2003-07-01

    Charts and parameters used to perform and analyzing the acoustic emission data collected during the hydrostatic test in pipe samples build in API XL 60 with 20 inches of diameter and 14 millimeters of thickness are shown. These pipes had internal and external artificial flaws done by electro-erosion process with aspect ratio 1 x 20. A relationship between acoustic emission results, ultrasound and J-Integral were established using the applied pressurization sequence. Characteristics values of acoustic emission signals were shown as a criteria of field tests. (author)

  20. The hydrostatic equilibrium and its implications on the mechanical properties of planets

    Directory of Open Access Journals (Sweden)

    M. CAPUTO

    1974-06-01

    Full Text Available Under the hypothesis of hydrostatic equilibrium the planets of the solar system are represented on the plane (J"2, w2 a?/MG (J2 = second term of the gravitational potential, w = rotation rate of the planet, a — equatorial radius, M — mass of the planet, G = gravitational constant. Since the points representing the planets lie on a straight line it is possible to obtain informations on the giration moment and the moment of inertia of Uranus and Pluto.

  1. Effects of high hydrostatic pressure on microflora and some quality attributes of grape juice

    Science.gov (United States)

    Mert, Mecnun; Buzrul, Sencer; Alpas, Hami

    2013-03-01

    Red and white grape juices were treated with high hydrostatic pressure (HHP) at three different pressures, temperature and time values to investigate the effects of HHP on natural microflora and some quality attributes of the juices. Increased pressure, temperature and time showed significant effect on the microbial reduction and no microbial growth were observed in HHP-treated grape juices up to 90 days. HHP had little or no effect on pH and color of the juices. Although 5-hydroxymethylfurfural (HMF) formation was observed in heat pasteurized samples, no HMF was detected in HHP-treated juices. This study demonstrated that HHP could be used as an alternative to heat treatment.

  2. A new experimental system for the extended application of cyclic hydrostatic pressure to cell culture.

    Science.gov (United States)

    Maul, Timothy M; Hamilton, Douglas W; Nieponice, Alejandro; Soletti, Lorenzo; Vorp, David A

    2007-02-01

    Mechanical forces have been shown to be important stimuli for the determination and maintenance of cellular phenotype and function. Many cells are constantly exposed in vivo to cyclic pressure, shear stress, and/or strain. Therefore, the ability to study the effects of these stimuli in vitro is important for understanding how they contribute to both normal and pathologic states. While there exist commercial as well as custom-built devices for the extended application of cyclic strain and shear stress, very few cyclic pressure systems have been reported to apply stimulation longer than 48 h. However, pertinent responses of cells to mechanical stimulation may occur later than this. To address this limitation, we have designed a new cyclic hydrostatic pressure system based upon the following design variables: minimal size, stability of pressure and humidity, maximal accessibility, and versatility. Computational fluid dynamics (CFD) was utilized to predict the pressure and potential shear stress within the chamber during the first half of a 1.0 Hz duty cycle. To biologically validate our system, we tested the response of bone marrow progenitor cells (BMPCs) from Sprague Dawley rats to a cyclic pressure stimulation of 120/80 mm Hg, 1.0 Hz for 7 days. Cellular morphology was measured using Scion Image, and cellular proliferation was measured by counting nuclei in ten fields of view. CFD results showed a constant pressure across the length of the chamber and no shear stress developed at the base of the chamber where the cells are cultured. BMPCs from Sprague Dawley rats demonstrated a significant change in morphology versus controls by reducing their size and adopting a more rounded morphology. Furthermore, these cells increased their proliferation under cyclic hydrostatic pressure. We have demonstrated that our system imparts a single mechanical stimulus of cyclic hydrostatic pressure and is capable of at least 7 days of continuous operation without affecting cellular

  3. Structural Tests of a Stainless Steel Wing Panel by Hydrostatic Loading

    Science.gov (United States)

    1940-11-01

    local puckers were visible aloa~ se~n lines, particularly at rib 2 near the wing bean and the trailing-ed~e spar. The soans in general were.sonewhat...dicatedfor future use of hydrostatic vi~g testing: .. 1. In orded to avoid,local seam ,.irregularities, lit- tle if any caulking paste should be p-dtwithin the... seam lap. Zinal watertightnes~ should he b — -.. — . —. .,-. — — . . — .-. . .s . .= -. * — NACA Technical Note No. 786 13 ., obtainei; in preference

  4. Effect of bulk modulus on performance of a hydrostatic transmission control system

    Indian Academy of Sciences (India)

    Ali Volkan Akkaya

    2006-10-01

    In this paper, we examine the performance of PID (proportional integral derivative) and fuzzy controllers on the angular velocity of a hydrostatic transmission system by means of Matlab-Simulink. A very novel aspect is that it includes the analysis of the effect of bulk modulus on system control. Simulation results demonstrates that bulk modulus should be considered as a variable parameter to obtain a more realistic model. Additionally, a PID controller is insufficient in presence of variable bulk modulus, whereas a fuzzy controller provides robust angular velocity control.

  5. Donor impurity-related intraband optical absorption in a single quantum ring: Hydrostatic pressure and intense laser field effects

    Science.gov (United States)

    Barseghyan, M. G.

    2016-10-01

    The simultaneous influence of hydrostatic pressure and intense laser field on hydrogenic donor impurity states and intraband optical absorption has been investigated in GaAs/Ga_{1-tilde{x}}Al_{tilde{x}}As quantum ring. The one-electron energy spectrum and wave functions have been found using the effective mass approximation and exact diagonalization technique. The intraband absorption coefficient is calculated for different values of the hydrostatic pressure, intense laser field parameter and different locations of hydrogenic donor impurity. The simultaneous influence of hydrostatic pressure and intense laser field shows that while the increment of the first one leads only to the blueshift of the absorption spectrum, the augmentation of the second one makes the redshift. In addition, both blueshift and redshift of the spectrum have been obtained with the changes of impurity location. The obtained theoretical results indicate good controlling means of the optical spectrum of ring-like structures by the combined influence of the considered factors.

  6. NASTRAN Structural Model for the Large 64-meter Antenna Pedestal. Part 3: Applications to Hydrostatic Bearing Oil Film

    Science.gov (United States)

    Chian, C. T.; Schonfeld, D.

    1984-01-01

    Investigations are conducted on the 64-meter antenna hydrostatic bearing oil film thickness under a variety of loads and elastic moduli. These parametric studies use a NASTRAN pedestal structural model to determine the deflections under the hydrostatic bearing pad. The deflections form the input for a computer program to determine the hydrostatic bearing oil film thickness. For the future 64-meter to 70-meter antenna extension and for the 2.2-meter (86-in.) haunch concrete replacement cases, safe oil film thickness (greater than 0.13 mm (0.005 in.) at the corners of the pad) are predicted. The effects of varying moduli of elasticity for different sections of the pedestal and the film height under distressed runner conditions are also studied.

  7. Synthetic observations of first hydrostatic cores in collapsing low-mass dense cores. I. Spectral energy distributions and evolutionary sequence

    CERN Document Server

    Commercon, Benoit; Dullemond, Cornelis P; Henning, Thomas

    2012-01-01

    The low-mass star formation evolutionary sequence is relatively well-defined both from observations and theoretical considerations. The first hydrostatic core is the first protostellar equilibrium object that is formed during the star formation process. Using state-of-the-art radiation-magneto-hydrodynamic 3D adaptive mesh refinement calculations, we aim to provide predictions for the dust continuum emission from first hydrostatic cores. We investigate the collapse and the fragmentation of magnetized one solar mass prestellar dense cores and the formation and evolution of first hydrostatic cores using the RAMSES code. We use three different magnetization levels for the initial conditions, which cover a large variety of early evolutionary morphology, e.g., the formation of a disk or a pseudo-disk, outflow launching, and fragmentation. We post-process the dynamical calculations using the 3D radiative transfer code RADMC-3D. We compute spectral energy distributions and usual evolutionary stage indicators such as...

  8. Survival analysis applied to the sensory shelf-life dating of high hydrostatic pressure processed avocado and mango pulps.

    Science.gov (United States)

    Jacobo-Velázquez, D A; Ramos-Parra, P A; Hernández-Brenes, C

    2010-08-01

    High hydrostatic pressure (HHP) pasteurized and refrigerated avocado and mango pulps contain lower microbial counts and thus are safer and acceptable for human consumption for a longer period of time, when compared to fresh unprocessed pulps. However, during their commercial shelf life, changes in their sensory characteristics take place and eventually produce the rejection of these products by consumers. Therefore, in the present study, the use of sensory evaluation was proposed for the shelf-life determinations of HHP-processed avocado and mango pulps. The study focused on evaluating the feasibility of applying survival analysis methodology to the data generated by consumers in order to determine the sensory shelf lives of both HHP-treated pulps of avocado and mango. Survival analysis proved to be an effective methodology for the estimation of the sensory shelf life of avocado and mango pulps processed with HHP, with potential application for other pressurized products. Practical Application: At present, HHP processing is one of the most effective alternatives for the commercial nonthermal pasteurization of fresh tropical fruits. HHP processing improves the microbial stability of the fruit pulps significantly; however, the products continue to deteriorate during their refrigerated storage mainly due to the action of residual detrimental enzymes. This article proposes the application of survival analysis methodology for the determination of the sensory shelf life of HHP-treated avocado and mango pulps. Results demonstrated that the procedure appears to be simple and practical for the sensory shelf-life determination of HHP-treated foods when their main mode of failure is not caused by increases in microbiological counts that can affect human health.

  9. B-splines as a Tool to Solve Constraints in Non-Hydrostatic Forecast Model

    CERN Document Server

    Subias, Alvaro

    2016-01-01

    Finite elements has been proven to be an useful tool to discretize the vertical coordinate in the hydrostatic forecast models allowing to define model variables in full levels so that no staggering is needed. In the non-hydrostatic case a constraint in the vertical operators appears (called C1) that does not allow to reduce the set of semi-implicit linear equations to a single equation in one variable as in the analytic case. Recently vertical finite elements based in B-splines have been used with an iterative method to relax the C1 constraint. In this paper we want to develop properly some representations of vertical operators in terms of B-splines in order to keep the C1-constraint. An invertibility relation between integral and derivative operators between vertical velocity and vertical divergence is also presented. The final scope of this paper is to provide a theoretical framework of development of finite element vertical operators to be implemented in the nh-Harmonie model

  10. Non-linear lattice response of Sm oxypnictides to hydrostatic pressure

    Science.gov (United States)

    Liarokapis, E.; Calamiotou, M.; Zhigadlo, N. D.; Katrych, S.; Karpinski, J.

    2013-10-01

    Hydrostatic pressure Raman measurements at room temperature have been carried out on the SmFeAsO (Sm1111) series of oxypnictides with various substitutions (F for O and Co for Fe) and transition temperature in order to investigate lattice modifications and their connection to doping and superconductivity. Synchrotron XRD data on some of these compounds indicated that at low doping the lattice constants vary smoothly with pressure, but with further increasing of the carrier concentration there is a deviation from the normal equation of state and these effects are related with modifications in the superconducting FeAs4 tetrahedra. The hydrostatic pressure Raman measurements indicate that the A1g mode of the rare earth atom for the superconducting compounds deviates from the linear pressure dependence at the same pressures where the XRD results show pressure-induced lattice anomalies. A similar anomaly is found for the As phonon of the same symmetry. As in cuprates, the effect is diminished in the non-superconducting compounds and it is not related with the F substitution being present in the Sm(Fe1-xCox)AsO as well. The calculated Grüneisen parameters indicate a more anharmonic phonon for the Fe atom compared with the Sm and As atoms.

  11. Qualitative novelty in seventeenth-century science: Hydrostatics from Stevin to Pascal.

    Science.gov (United States)

    Chalmers, Alan F

    2015-06-01

    Two works on hydrostatics, by Simon Stevin in 1586 and by Blaise Pascal in 1654, are analysed and compared. The contrast between the two serves to highlight aspects of the qualitative novelty involved in changes within science in the first half of the seventeenth century. Stevin attempted to derive his theory from unproblematic postulates drawn from common sense but failed to achieve his goal insofar as he needed to incorporate assumptions involved in his engineering practice but not sanctioned by his postulates. Pascal's theory went beyond common sense by introducing a novel concept, pressure. Theoretical reflection on novel experiments was involved in the construction of the new concept and experiment also provided important evidence for the theory that deployed it. The new experimental reasoning was qualitatively different from the Euclidean style of reasoning adopted by Stevin. The fact that a conceptualization of a technical sense of pressure adequate for hydrostatics was far from obvious is evident from the work of those, such as Galileo and Descartes, who did not make significant moves in that direction. Copyright © 2015 Elsevier Ltd. All rights reserved.

  12. Linear and Nonlinear Behavior Analysis of a Flexible Shaft Supported By Hydrostatic Squeeze Film Dampers

    Directory of Open Access Journals (Sweden)

    A. Bouzidane

    2014-01-01

    Full Text Available Linear and non linear models of a hydrostatic squeeze film damper are presented and numerically simulated by a step by step method on a modal basis, in order to study the non-linear dynamic behaviour of a flexible shaft. The Reynolds equation is solved at each step in order to evaluate the film forces. The equations of motion are then integrated by using the Newmark method with a variable step in order to obtain speeds and the position for the next step. The non-linear hydrostatic forces are determined by the application of the boundary conditions, and the integration of the pressure field is determined by resolution of Reynolds equation, by applying the central finite difference method. The aim of this research is to study the effect of pressure ratio, viscosity, and rotational speeds on the vibratory responses and the transmitted bearing forces. The results are discussed, analysed and compared to a linear approach which is restricted to only small vibrations around the equilibrium position. The results show good agreements between linear and non-linear methods when the unbalance force is small, and then the linear model may be used for small vibrations in order to reduce compilation time during the iterative process.

  13. The principal moments of inertia calculated with the hydrostatic equilibrium figure of the Earth

    Directory of Open Access Journals (Sweden)

    Chengjun Liu

    2017-05-01

    Full Text Available As an indication of the Earth's mass distribution, the principal moments of inertia (PMOI, i.e., A, B, C of the Earth are the basic parameters in studies of the global dynamics of the earth, like earth nutation, and the geophysics. From the aspect of observation, the PMOI can be calculated from the spherical coefficients of observed gravity field. In this paper, the PMOI are calculated directly according to its definition with the figures of the Earth's interior derived by a generalized theory of the hydrostatic equilibrium figure of the Earth. We obtain that the angle between the principal axis of the maximum moment of PMOI and the rotational axis is 0.184°, which means that the other two principal axes are very closely in the equatorial plane. Meanwhile, B-A is 1.60 × 10−5 MR2, and the global dynamical flattening (H is calculated to be 3.29587 × 10−3, which is 0.67% different from the latest observation derived value Hobs(3.273795 × 10−3 (Petit and Luzum, 2010, and this is a significant improvement from the 1.1% difference between the value of H derived from traditional theories of the figure of the Earth and the value of Hobs. It shows that we can calculate the PMOI and H with an appropriate accuracy by a generalized theory of the hydrostatic equilibrium figure of the Earth.

  14. Hydrostatic Simulation of Earth's Atmospheric Gas Using Multi-particle Collision Dynamics

    Science.gov (United States)

    Pattisahusiwa, Asis; Purqon, Acep; Viridi, Sparisoma

    2016-01-01

    Multi-particle collision dynamics (MPCD) is a mesoscopic simulation method to simulate fluid particle-like flows. MPCD has been widely used to simulate various problems in condensed matter. In this study, hydrostatic behavior of gas in the Earth's atmospheric layer is simulated by using MPCD method. The simulation is carried out by assuming the system under ideal state and is affected only by gravitational force. Gas particles are homogeneous and placed in 2D box. Interaction of the particles with the box is applied through implementation of boundary conditions (BC). Periodic BC is applied on the left and the right side, specular reflection on the top side, while bounce-back on the bottom side. Simulation program is executed in Arch Linux and running in notebook with processor Intel i5 @2700 MHz with 10 GB DDR3 RAM. The results show behaviors of the particles obey kinetic theory for ideal gas when gravitational acceleration value is proportional to the particle mass. Density distribution as a function of altitude also meets atmosphere's hydrostatic theory.

  15. Response of superconductivity and crystal structure of LiFeAs to hydrostatic pressure.

    Science.gov (United States)

    Mito, Masaki; Pitcher, Michael J; Crichton, Wilson; Garbarino, Gaston; Baker, Peter J; Blundell, Stephen J; Adamson, Paul; Parker, Dinah R; Clarke, Simon J

    2009-03-04

    On the application of hydrostatic pressures of up to 1.3 GPa, the superconducting transition temperatures (T(c)) of samples of LiFeAs are lowered approximately monotonically at approximately -2 K GPa(-1). Measurements of the X-ray powder diffraction pattern at hydrostatic pressures of up to 17 GPa applied by a He gas pressure medium in a diamond anvil cell reveal a bulk modulus for LiFeAs of 57.3(6) GPa which is much smaller than that of other layered arsenide and oxyarsenide superconductors. LiFeAs also exhibits much more isotropic compression than other layered iron arsenide superconductors. The higher and more isotropic compressibility is presumably a consequence of the small size of the lithium ion. At ambient pressure the FeAs(4) tetrahedra are the most compressed in the basal plane of those in any of the superconducting iron arsenides. On increasing the pressure the Fe-Fe distance contracts more rapidly than the Fe-As distance so that the FeAs(4) tetrahedra become even more distorted from the ideal tetrahedral shape. The decrease in T(c) with applied pressure is therefore consistent with the observations that in the iron arsenides and related materials investigated thus far, T(c) is maximized for a particular electron count when the FeAs(4) tetrahedra are close to regular.

  16. Failure assessment of aluminum liner based filament-wound hybrid riser subjected to internal hydrostatic pressure

    Science.gov (United States)

    Dikshit, Vishwesh; Seng, Ong Lin; Maheshwari, Muneesh; Asundi, A.

    2015-03-01

    The present study describes the burst behavior of aluminum liner based prototype filament-wound hybrid riser under internal hydrostatic pressure. The main objective of present study is to developed an internal pressure test rig set-up for filament-wound hybrid riser and investigate the failure modes of filament-wound hybrid riser under internal hydrostatic burst pressure loading. The prototype filament-wound hybrid riser used for burst test consists of an internal aluminum liner and outer composite layer. The carbon-epoxy composites as part of the filament-wound hybrid risers were manufactured with [±55o] lay-up pattern with total composite layer thickness of 1.6 mm using a CNC filament-winding machine. The burst test was monitored by video camera which helps to analyze the failure mechanism of the fractured filament-wound hybrid riser. The Fiber Bragg Grating (FBG) sensor was used to monitor and record the strain changes during burst test of prototype filament-wound hybrid riser. This study shows good improvements in burst strength of filament-wound hybrid riser compared to the monolithic metallic riser. Since, strain measurement using FBG sensors has been testified as a reliable method, we aim to further understand in detail using this technique.

  17. Hydrostatically coupled dielectric elastomer actuators for tactile displays and cutaneous stimulators

    Science.gov (United States)

    Carpi, Federico; Frediani, Gabriele; De Rossi, Danilo

    2010-04-01

    Hydrostatic coupling has been recently reported as a means to improve versatility and safety of dielectric elastomer (DE) actuators. Hydrostatically coupled DE actuators rely on an incompressible fluid that mechanically couples a DE-based active part to a passive part interfaced to the load. In this paper, we present ongoing development of bubble-like versions of such transducers, made of silicone and oil. In particular, the paper describes millimeter-scale actuators, currently being developed as soft, light, acoustically silent and cheap devices for two types of applications: tactile displays and cutaneous stimulators. In both cases, the most significant advantages of the proposed technology are represented by high versatility for design (due to the fluid based transmission mechanism), tailorable stiffness perceived by the user (obtained by adjusting the internal fluid pressure), and suitable electrical safety (enabled by both a passive interface with the user and the insulating internal fluid). Millimeter-scale prototypes showed a resonance frequency of about 250 Hz, which represents the value at which Pacinian cutaneous mechanoreceptors exhibit maximum sensitivity; this provides an optimum condition to eventually code tactile information dynamically, either in combination or as an alternative to static driving.

  18. Effect of the hydrostatic pressure on the electron mobility in delta-doped systems

    Energy Technology Data Exchange (ETDEWEB)

    Oubram, O; Mora-Ramos, M E; Gaggero-Sager, L M, E-mail: 1gaggero@uaem.m [Facultad de Ciencias, Universidad Autonoma del Estado de Morelos, Av. Universidad 1001, CP 62209, Cuernavaca, Morelos (Mexico)

    2009-05-01

    The influence of hydrostatic pressure on the electron states and low-temperature mobility in n-type GaAs delta-doped single quantum wells is studied. Values of hydrostatic pressure consider are below the so-called GAMMA-X crossover, keeping all attention in the electronic properties at the Brillouin zone center. The effect of the pressure on the electron mobility is described via a relative quantity that is proportional to the ratio between P not = 0 and zero pressure results. Calculation is performed using an analytical description of the potential energy function profile, based on the Thomas-Fermi approach, taking explicitly into account the dependence upon P of the main input parameters: effective masses and dielectric constant. The relative mobility increases for higher values of P. The cases of zero and finite -although small- temperature are studied, showing that the influence of T is mainly to lower the values of the relative mobility in the entire range of P considered. Numerical results are reported for a two-dimensional density of ionized impurities equals to 7.5 x 10{sup 12} cm{sup -2}.

  19. Chondroitin sulphate extracted from antler cartilage using high hydrostatic pressure and enzymatic hydrolysis

    Directory of Open Access Journals (Sweden)

    Chong-Tai Kim

    2014-12-01

    Full Text Available Chondroitin sulphate (CS, a major glycosaminoglycan, is an essential component of the extracellular matrix in cartilaginous tissues. Wapiti velvet antlers are a rich source of these molecules. The purpose of the present study was to develop an effective isolation procedure of CS from fresh velvet antlers using a combination of high hydrostatic pressure (100 MPa and enzymatic hydrolysis (papain. High CS extractability (95.1 ± 2.5% of total uronic acid was obtained following incubation (4 h at 50 °C with papain at pH 6.0 in 100 MPa compared to low extractability (19 ± 1.1% in ambient pressure (0.1 MPa. Antler CS fractions were isolated by Sephacryl S-300 chromatography and identified by western blot using an anti-CS monoclonal antibody. The antler CS fraction did not aggregate with hyaluronic acid in CL-2B chromatography and possessed DPPH radical scavenging activity at 78.3 ± 1.5%. The results indicated that high hydrostatic pressure and enzymatic hydrolysis procedure may be a useful tool for the isolation of CS from antler cartilaginous tissues.

  20. The effect of hydrostatic vs. shock pressure treatment of plant seeds

    Science.gov (United States)

    Mustey, A.; Leighs, J. A.; Appleby-Thomas, G. J.; Wood, D. C.; Hazael, R.; McMillan, P. F.; Hazell, P. J.

    2014-05-01

    The hydrostatic pressure and shock response of plant seeds has been investigated antecedently, primarily driven by interest in reducing bacterial contamination of crops and the theory of panspermia, respectively. However, comparisons have not previously been made between these two methods ofapplying pressure to plant seeds. Here such a comparison has been undertaken based on the premise that any correlations in collected data may provide a route to inform understanding of damage mechanisms in the seeds under test. In this work two varieties of plant seeds were subjected to hydrostatic pressure via a non-end-loaded piston cylinder setup and shock compression via employment of a 50 mm bore, single stage gas gun using the flyer plate technique. Results from germination tests of recovered seed samples have been compared and contrasted, and initial conclusions made regarding causes of trends in the resultant data-set. Data collected has shown that cress seeds are extremely resilient to static loading, whereas the difference in the two forms of loading is negligible for lettuce seeds. Germination time has been seen to extend dramatically following static loading of cress seeds to greater than 0.4 GPa. In addition, the cut-off pressure previously seen to cause 0% germination in dynamic experiments performed on cress seeds has now also been seen in lettuce seeds.

  1. Microstructure and mechanical properties of duplex stainless steel subjected to hydrostatic extrusion

    Energy Technology Data Exchange (ETDEWEB)

    Maj, P., E-mail: Piotr.maj@inmat.pw.edu.pl [Faculty of Materials Science and Engineering, Warsaw University of Technology, Wołoska 141, 02-507 Warsaw (Poland); Adamczyk-Cieślak, B.; Mizera, J. [Faculty of Materials Science and Engineering, Warsaw University of Technology, Wołoska 141, 02-507 Warsaw (Poland); Pachla, W. [High Pressure Research Center, Polish Academy of Sciences, Sokołowska 29, 01-142 Warsaw (Poland); Kurzydłowski, K.J. [Faculty of Materials Science and Engineering, Warsaw University of Technology, Wołoska 141, 02-507 Warsaw (Poland)

    2014-07-01

    The nanostructure and mechanical properties of ferritic-austenitic duplex stainless steel subjected to hydrostatic extrusion were examined. The refinement of the structure in the initial state and in the two deformation states (ε = 1.4 and ε = 3.8) was observed in an optical microscope (OM) and a transmission electron microscope (TEM). The results indicate that the structure evolved from microcrystalline with a grain size of about 4 μm to nanocrystalline with a grain size of about 150 nm in ferrite and 70 nm in austenite. The material was characterized mechanically by tensile tests performed in the two deformation states. The ultimate strength appeared to increase significantly compared to that in the initial deformation stages, which can be attributed to the grain refinement and plastic deformation. The heterogeneity observed in microregions results from the dual-phase structure of the steel. The results indicate that hydrostatic extrusion is a highly potential technology suitable for improving the properties of duplex steels. - Highlights: • Duplex stainless steel was hydro extruded to a total strain of 3.8 • After the last stage of deformation heterogeneous structure was obtained in the material • As a result of stresses non-diffusive transformation γ→α’ occurred in the material • Nanometric (sub)grains were obtained in the austenite regions.

  2. First principles investigation of magnesium antimonite semiconductor compound in two different phases under hydrostatic pressure

    Science.gov (United States)

    Sedighi, Matin; Nia, Borhan Arghavani; Zarringhalam, Hanif; Moradian, Rostam

    2011-09-01

    We investigate the electronic and the structural properties of Mg 3Sb 2 in cubic and hexagonal phases using the full potential-linearized augmented plane wave (FP-LAPW) method within the framework of density functional theory. The effects of hydrostatic pressure on band gap, bandwidths of bands under Fermi energy labeled by B1 and B2 from the top, the energy gap between B1 and B2 (anti-symmetry gap) and also effective masses of electrons and holes are studied using optimized lattice parameters. We observe that the hydrostatic pressure decreases the band gap and the anti-symmetry gap while it increases the bandwidths of all bands below the Fermi energy. The effective masses of electrons and holes for the hexagonal phase depend on pressure in the Γ→ Λ direction. In the cubic phase the effective mass of electrons is independent of pressure and the effective mass of holes depend on the pressure in the Γ→ N direction.

  3. Phonon and Elastic Instabilities in Zincblende TlN under Hydrostatic Pressure from First Principles Calculations

    Institute of Scientific and Technical Information of China (English)

    SHI Li-Wei; DUAN Yi-Feng; YANG Xian-Qing; TANG Gang

    2011-01-01

    The lattice dynamic and elastic instabilities of zincblende (ZB) thallium nitride (TIN) under hydrostatic pressure are extensively studied to reveal the physically driven mechanism of phase transition from the ZB to a rocksalt structure using pseudopotential plane-wave density functional calculations within the local density approximation. Our calculated results shows that both transverse acoustic phonon mode softening behavior and elastic instability are responsible for the pressure-induced structural phase transition in ZB TIN.%The lattice dynamic and elastic instabilities of zincblende (ZB) thallium nitride (TlN) under hydrostatic pressure are extensively studied to reveal the physically driven mechanism of phase transition from the ZB to a rocksalt structure using pseudopotential plane-wave density functional calculations within the local density approximation.Our calculated results shows that both transverse acoustic phonon mode softening behavior and elastic instability are responsible for the pressure-induced structural phase transition in ZB TlN.Recently,thallium nitride (TlN) was predicted to have a small or even negative energy gap,indicating a semi-metallic character.Thus the combination of thallium with other wide-gap ⅢA-nitrides yields interesting novel ternary semiconducting alloys such as Al1-xTlxN,[1] and Ga1-xTlxN,[2] whose phonon energies can encompass the near-infrared region extending well into the ultraviolet spectral range,with great potential in optical communication systems.

  4. Effect of high hydrostatic pressure on the barrier properties of polyamide-6 films

    Directory of Open Access Journals (Sweden)

    Schmerder A.

    2005-01-01

    Full Text Available Little is known about the barrier properties of polymer films during high pressure processing of prepackaged foods. In order to learn more about this, we examined the influence of high hydrostatic pressure on the permeation of raspberry ketone (dissolved in ethanol/water through polyamide-6 films at temperatures between 20 and 60ºC. Permeation was lowered by increasing pressure at all temperatures. At 23°C, the increasing pressure sequence 0.1, 50, 100, 150, and 200 MPa correlated with the decreasing permeation coefficients P/(10(9 cm² s-1 of 6.2, 3.8, 3.0, 2.2, and 1.6. Analysis of the permeation kinetics indicated that this effect was due to a reduced diffusion coefficient. Pressure and temperature acted antagonistically to each other. The decrease in permeation at 200 MPa was compensated for by a temperature increase of 20ºC. After release of pressure, the former permeation coefficients were recovered, which suggests that this `pressure effect' is reversible. Taken together, our data revealed no detrimental effects of high hydrostatic pressure on the barrier properties of polymer films.

  5. 管道的冲洗和水压试验%Flushing and Hydrostatic Testing of the Pipeline

    Institute of Scientific and Technical Information of China (English)

    杜静

    2012-01-01

      Pipeline flushing and hydrostatic testing is very important in pipeline instal ation work . we should be ful y aware of its importance.This paper describes the flushing and hydrostatic testing of the pipeline and some considerations.%  管道冲洗、水压试验在管道的安装工作中非常重要,要充分认识到它的重要性。本文阐述一下常用的管道冲洗和水压试验的方法及一些注意事项。

  6. Towards an energy-conserving quasi-hydrostatic deep-atmosphere dynamical core

    Science.gov (United States)

    Tort, Marine; Dubos, Thomas

    2014-05-01

    Towards an energy-conserving quasi-hydrostatic deep-atmosphere dynamical core Marine Tort1 & Thomas Dubos1 1 Laboratoire Météorologique Dynamique, Ecole Polytechnique, Palaiseau, FRANCE Atmosphere dynamics of our planet is quite well described by traditional primitive equations based on the so-called shallow-atmosphere approximation. Thus, the model is dynamically consistent (in the sense that it possesses conservation principles for mass, energy, potential vorticity and angular momentum) when certain metric terms and the cosφ Coriolis terms are neglected (Phillips, 1966). Nevertheless, to simulate planetary atmospheres, the shallow-atmosphere approximation should be relaxed because of the low planet radius (such as Titan) or the depth of their atmospheres (such as Jupiter or Saturne). Non-traditional terms have some dynamical effects (Gerkema and al., 2008) but they are little-known and rarely integrated into general circulation dynamical cores (Wood and Staniforth, 2002). As an example, the french GCM of the Laboratoire Météorologique Dynamique (LMD-Z) integrates the traditional primitive equations discretized from their curl (vector-invariant) form based on a finite different scheme whose conserves exactly potential vorticity (Sadourny, 1975a,b). We considered an orthogonal curvilinear system and we first derived a curl form of global, deep-atmosphere quasi-hydrostatic model in which prognostic variable is absolute axial momentum instead of relative velocity vector. Given the close relationship between the curl form and Hamiltonian formulation of the previous equations, we generalized Sadourny's energy-conserving formulation by discretizing the Poisson bracket and the energy themselves (Salmon, 1983; Gassmann, 2013). The substantial computing infrastructure of the dynamical core is the same but the modification of the hydrostatic balance requires a mass-based vertical coordinate (Wood and Staniforth, 2003). The new discretization has been implemented into

  7. H2O in stellar atmospheres. II. ISO spectra of cool red giants and hydrostatic models

    Science.gov (United States)

    Aringer, B.; Kerschbaum, F.; Jörgensen, U. G.

    2002-12-01

    We present 26 ISO-SWS spectra taken from a sample of 13 M-type Semiregular, Lb and Mira variables and covering the wavelength range between 2.36 and 5 mu m at a medium resolution. All of the studied objects show intense water bands producing a deep absorption dip around 2.5 mu m. Features of CO, OH, SiO and CO2 are also visible. Using the new H2O linelist published in the first paper of this series and available opacity data for the other important molecules, we calculated a grid of hydrostatic MARCS atmospheres and the corresponding synthetic ISO-SWS spectra. Based on the comparison with these theoretical results the ISO observations can be divided into four classes. The first two groups include the spectra of the Semiregular (SRb) and Lb variables in our sample. For all of them the region between 2.36 and 4.2 mu m can be quite well reproduced by our hydrostatic models. Only the predicted SiO bands above 4 mu m are in some cases too strong which is due to known dynamical effects. Depending on the temperature (above or below 3000 K) of the atmosphere, which mainly determines the intensity of the water depression at 2.5 mu m, the spectra of the Semiregular and Lb variables fall into the first or second class. The third group consists of observations of Mira stars obtained around maximum light where the range between 2.36 and 4.2 mu m can be fitted with our MARCS models except for a strong emission bump appearing in the ISO-SWS data in the region of the SiO features and the slope very close to the short wavelength border. Finally, the last type of spectra corresponds to Mira variables during the phases around the minimum of their visual light curve. For this class the observed water absorption at 2.5 mu m is much more intense than in any hydrostatic atmosphere with a realistic choice of effective temperature and surface gravity. Thus, we conclude that dynamical models are needed to explain the ISO-SWS data of Mira stars. For all of the cooler objects from our sample

  8. Inactivation of Salmonella enterica and Listeria monocytogenes in cantaloupe puree by high hydrostatic pressure with/without added ascorbic acid

    Science.gov (United States)

    The objective of this research was to evaluate and develop a method for inactivation of Salmonella enterica and Listeria monocytogenes in cantaloupe puree (CP) by high hydrostatic pressure (HHP). Cantaloupe being the most netted varieties of melons presents a greater risk of pathogen transmission. ...

  9. Non-hydrostatic behavior of KBr as a pressure medium in diamond anvil cells up to 5.63 GPa.

    Science.gov (United States)

    Zhao, Jing; Ross, Nancy L

    2015-05-13

    Non-hydrostatic stresses of KBr acting as a pressure-transmitting medium have been investigated by examining their effect on a single crystal of quartz in a diamond anvil cell (DAC). The lattice strains or distortions were measured by single-crystal x-ray diffraction methods, and the non-hydrostatic deviatoric stresses for KBr were determined up to 5.63(2) GPa. The experimental results show that differences between axial stress components in the direction normal to the DAC culet face and the radial stress components in directions parallel to the DAC culet face are about 0.063(24) GPa at pressures below 2.14 GPa, and the pressure-transmitting medium can therefore be considered as quasi-hydrostatic up to this pressure. However above 2.14 GPa, after the phase transition pressure of KBr during which it converts from the B1 phase to the B2 phase, the deviatoric stresses constantly increase with increasing pressure. At the maximum pressure of this study, 5.63(2) GPa, the difference between axial stress and radial stress components reaches 0.93(9) GPa. Different variations in the non-hydrostatic deviatoric stresses were observed during both compression and decompression of the DAC, and are mainly ascribed to the phase-transition-induced volume change of KBr.

  10. Coexistence of Dirac and massive carriers in α-(BEDT-TTF){sub 2}I{sub 3} under hydrostatic pressure

    Energy Technology Data Exchange (ETDEWEB)

    Navarin, Fabien; Tisserond, Emilie [Laboratoire de Physique des Solides, UMR 8502, CNRS-Université Paris-Sud, Orsay F-91405 (France); Auban-Senzier, Pascale, E-mail: pascale.senzier@u-psud.fr [Laboratoire de Physique des Solides, UMR 8502, CNRS-Université Paris-Sud, Orsay F-91405 (France); Mézière, Cécile; Batail, Patrick [MOLTECH-Anjou, UMR 6200, CNRS-Université d' Angers, Bat. K, Angers F-49045 (France); Pasquier, Claude; Monteverde, Miguel [Laboratoire de Physique des Solides, UMR 8502, CNRS-Université Paris-Sud, Orsay F-91405 (France)

    2015-03-01

    We present magnetotransport measurements of α-(BEDT-TTF){sub 2}I{sub 3} crystals under hydrostatic pressure larger than 1.5 GPa where Dirac carriers are present. We show not only the existence of high-mobility Dirac carriers but we also prove experimentally the presence of low-mobility massive carriers, in agreement with band-structure calculations.

  11. Data analysis of the inactivation of foodborne microorganisms under high hydrostatic pressure to establish global kinetic parameters and influencing factors

    NARCIS (Netherlands)

    Santillana Farakos, S.M.; Zwietering, M.H.

    2011-01-01

    The inactivation rate of foodborne microorganisms under high hydrostatic pressure (HHP) is influenced by factors such as substrate, species, strain, temperature, pH, and stage of growth of the cell. In this study, 445 DP-values from previously published data were analyzed, including those from bacte

  12. Evaluation of the Growth Environment of a Hydrostatic Force Bioreactor for Preconditioning of Tissue-Engineered Constructs

    Science.gov (United States)

    Reinwald, Yvonne; Leonard, Katherine H.L.; Henstock, James R.; Whiteley, Jonathan P.; Osborne, James M.; Waters, Sarah L.; Levesque, Philippe

    2015-01-01

    Bioreactors have been widely acknowledged as valuable tools to provide a growth environment for engineering tissues and to investigate the effect of physical forces on cells and cell-scaffold constructs. However, evaluation of the bioreactor environment during culture is critical to defining outcomes. In this study, the performance of a hydrostatic force bioreactor was examined by experimental measurements of changes in dissolved oxygen (O2), carbon dioxide (CO2), and pH after mechanical stimulation and the determination of physical forces (pressure and stress) in the bioreactor through mathematical modeling and numerical simulation. To determine the effect of hydrostatic pressure on bone formation, chick femur skeletal cell-seeded hydrogels were subjected to cyclic hydrostatic pressure at 0–270 kPa and 1 Hz for 1 h daily (5 days per week) over a period of 14 days. At the start of mechanical stimulation, dissolved O2 and CO2 in the medium increased and the pH of the medium decreased, but remained within human physiological ranges. Changes in physiological parameters (O2, CO2, and pH) were reversible when medium samples were placed in a standard cell culture incubator. In addition, computational modeling showed that the distribution and magnitude of physical forces depends on the shape and position of the cell-hydrogel constructs in the tissue culture format. Finally, hydrostatic pressure was seen to enhance mineralization of chick femur skeletal cell-seeded hydrogels. PMID:24967717

  13. A Variational Formalism for the Radiative Transfer Equation and a Geostrophic, Hydrostatic Atmosphere: Prelude to Model 3

    Science.gov (United States)

    Achtemeier, Gary L.

    1991-01-01

    The second step in development of MODEL III is summarized. It combines the four radiative transfer equations of the first step with the equations for a geostrophic and hydrostatic atmosphere. This step is intended to bring radiance into a three dimensional balance with wind, height, and temperature. The use of the geostrophic approximation in place of the full set of primitive equations allows for an easier evaluation of how the inclusion of the radiative transfer equation increases the complexity of the variational equations. Seven different variational formulations were developed for geostrophic, hydrostatic, and radiative transfer equations. The first derivation was too complex to yield solutions that were physically meaningful. For the remaining six derivations, the variational method gave the same physical interpretation (the observed brightness temperatures could provide no meaningful input to a geostrophic, hydrostatic balance) at least through the problem solving methodology used in these studies. The variational method is presented and the Euler-Lagrange equations rederived for the geostrophic, hydrostatic, and radiative transfer equations.

  14. Prediction of ship-ship interactions in ports by a non-hydrostatic model

    Institute of Scientific and Technical Information of China (English)

    周明贵; 邹早建

    2015-01-01

    Complicated channel geometry and currents may aggravate the interactions between passing ships and berthed ships, which should be evaluated and taken into account in a port design. A method for predicting the ship-ship interactions, based on a non-hydrostatic shallow water flow model, is presented in this paper and is validated by comparing the numerical results with experimental data. The method is subsequently applied to predict the interaction forces acting on a berthed ship due to a passing ship in ports. The influences of the difference of the water depths between the dock and the main channel, the dock geometry, the current and another berthed ship in the dock on the ship-ship interactions are studied. Analysis based on the numerical results is carried out, which is useful for the port design.

  15. Sorbitol counteracts high hydrostatic pressure-induced denaturation of inulin fructotransferase.

    Science.gov (United States)

    Li, Yungao; Miao, Ming; Liu, Miao; Jiang, Bo; Zhang, Tao; Chen, Xiangyin

    2014-09-01

    Inulin fructotransferase (IFTase), a novel hydrolase for inulin, was exposed to high hydrostatic pressure (HHP) at 400 and 600 MPa for 15 min in the presence or absence of sorbitol. Sorbitol protected the enzyme against HHP-induced activity loss. The relative residual activity increased nearly 3.1- and 3.8-fold in the presence of 3 mol/L sorbitol under 400 MPa and 600 MPa for 15 min, respectively. Circular dichroism results indicated that the original chaotic unfolding conformation of the enzyme under HHP shifted toward more ordered and impact with 3 mol/L sorbitol. Fluorescence and UV spectra results suggested that sorbitol prevented partially the unfolding of the enzyme and stabilized the conformation under high pressure. These results might be attributed to the binding of sorbitol on the surface of IFTase to rearrange and strengthen intra- and intermolecular hydrogen bonds.

  16. Processing of Copper by Hydrostatic Extrusion – Studies of Microstructure and Properties

    Directory of Open Access Journals (Sweden)

    Leszczyńska-Madej B.

    2016-09-01

    Full Text Available The present study attempts to apply HE to 99.99% pure copper. The microstructure of the samples was investigated by both light microscopy and scanning transmission electron microscopy (STEM. Additionally, the microhardness was measured, the tensile test was made, and statistical analysis of the grains and subgrains was performed. Based on Kikuchi diffraction patterns, misorientation was determined. The obtained results show that microstructure of copper deformed by hydrostatic extrusion (HE is rather inhomogeneous. The regions strongly deformed with high dislocation density exist near cells and grains/subgrains free of dislocations. The measurements of the grain size have revealed that the sample with an initial in annealed-state grain size of about 250 μm had this grain size reduced to below 0.35μm when it was deformed by HE to the strain ε=2.91. The microhardness and UTS are stable within the whole investigated range of deformation.

  17. The fusogenic state of Mayaro virus induced by low pH and by hydrostatic pressure.

    Science.gov (United States)

    Freitas, Monica; Da Poian, Andrea T; Barth, Ortrud M; Rebello, Moacyr A; Silva, Jerson L; Gaspar, Luciane P

    2006-01-01

    Mayaro virus is an enveloped virus that belongs to the Alphavirus genus. To gain insight into the mechanism involved in Mayaro virus membrane fusion, we used hydrostatic pressure and low pH to isolate a fusion-active state of Mayaro glycoproteins. In response to pressure, E1 glycoprotein undergoes structural changes resulting in the formation of a stable conformation. This state was characterized and correlated to that induced by low pH as measured by intrinsic fluorescence, 4,4'-dianilino-1,1'-binaphthyl-5,5'-disulfonic acid, dipotassium salt fluorescence, fluorescence resonance energy transfer, electron microscopy, and sodium dodecyl sulfate-polyacrylamide gel electrophoresis. In parallel, we used a neutralization assay to show that Mayaro virus in the fusogenic state retained most of the original immunogenic properties and could elicit high titers of neutralizing antibodies.

  18. Simple Hydrostatic Model of Contact Angle Hysteresis of a Sessile Drop on Rough Surface

    Institute of Scientific and Technical Information of China (English)

    毛在砂; 杨超; 陈家镛

    2005-01-01

    The phenomenon of hysteresis of contact angle is an important topic subject to a long time of argument.A simple hydrostatic model of sessile drops under the gravity in combination with an ideal surface roughness model is used to interpret the process of drop volume increase or decrease of a planar sessile drop and to shed light on the contact angle hysteresis and its relationship with the solid surface roughness. With this model, the advancing and receding contact angles are conceptually explained in terms of equilibrium contact angle and surface roughness only,without invoking the thermodynamic multiplicity. The model is found to be qualitatively consistent to experimental observations on contact angle hysteresis and it suggests a possible way to approach the hysteresis of three-dimensional sessile drops.

  19. Suppression of first cleavage in the Mexican axolotl (Ambystoma mexicanum) by heat shock or hydrostatic pressure

    Energy Technology Data Exchange (ETDEWEB)

    Gillespie, L.L.; Armstrong, J.B.

    1981-12-01

    Androgenetic diploid axolotls were produced by ultraviolet inactivation of the egg pronucleus shortly after fertilization, followed by suppression of the first cleavage division by hydrostatic pressure or heat shock. After treatment at 14,000 psi for 8 minutes, diploidy was restored in 74% of the embryos, but only 0.8% survived to hatching. A 36-37 degrees C heat shock of 10-minutes duration, applied 5.5 hours after the eggs were collected, yielded a slightly lower percentage of diploids. However, the proportion surviving to hatching was significantly greater (up to 4.6%). A second generation of androgenetic diploids was produced from one of the oldest of the first generation males with a similar degree of success. The lack of significant improvement suggests that the low survival is due to the heat shock per se and not to the uncovering of recessive lethal genes carried by the parent.

  20. Density Measurement System for Weights of 1 kg to 20 kg Using Hydrostatic Weighing

    Science.gov (United States)

    Lee, Yong Jae; Lee, Woo Gab; Abdurahman, Mohammed; Kim, Kwang Pyo

    This paper presents a density measurement system to determine density of weights from 1 kg to 20 kg using hydrostatic weighing. The system works based on Archimedes principle. The density of reference liquid is determined using this setup while determining the density of the test weight. Density sphere is used as standard density ball to determine density of the reference liquid. A new immersion pan is designed for dual purpose to carry the density sphere and the cylindrical test weight for weighing in liquid. Main parts of the setup are an electronic balance, a thermostat controlled liquid bath, reference weights designed for bottom weighing, dual purpose immersion pans and stepping motors to load and unload in weighing process. The results of density measurement will be evaluated as uncertainties for weights of 1 kg to 20 kg.

  1. Lifetime prediction for organic coating under alternating hydrostatic pressure by artificial neural network

    Science.gov (United States)

    Tian, Wenliang; Meng, Fandi; Liu, Li; Li, Ying; Wang, Fuhui

    2017-01-01

    A concept for prediction of organic coatings, based on the alternating hydrostatic pressure (AHP) accelerated tests, has been presented. An AHP accelerated test with different pressure values has been employed to evaluate coating degradation. And a back-propagation artificial neural network (BP-ANN) has been established to predict the service property and the service lifetime of coatings. The pressure value (P), immersion time (t) and service property (impedance modulus |Z|) are utilized as the parameters of the network. The average accuracies of the predicted service property and immersion time by the established network are 98.6% and 84.8%, respectively. The combination of accelerated test and prediction method by BP-ANN is promising to evaluate and predict coating property used in deep sea.

  2. Optimization of Inactivation Conditions of High Hydrostatic Pressure Using Response Surface Methodology

    Institute of Scientific and Technical Information of China (English)

    GAO Yu-long; WANG Yun-xiang; JIANG Han-hu

    2004-01-01

    Response surface methodology(RSM)was employed in the present work and a second order quadratic equation for high hydrostatic pressure(HHP)inactivation was built.The adequacy of the model equation for predicting the optimum response values was verified effectively by the validation data.Effects of temperature,pressure,and pressure holding time on HHP inactivation of Escherichia coli ATCC 8739 were explored.By analyzing the response surface plots and their corresponding contour plots as well as solving the quadratic equation,the optimum process parameters for inactivation E.coli of six log cycles were obtained as:temperature 32.2℃,pressure 346.4 MPa,and pressure holding time 12.6 min.

  3. Effect of hydrostatic pressure on the structural, elastic and electronic properties of (B3) boron phosphide

    Indian Academy of Sciences (India)

    Salah Daoud; Kamel Loucif; Nadhira Bloud; Noudjoud Lebgaa; Laarbi Belagraa

    2012-07-01

    In this paper we present the results obtained from first-principles calculations of the effect of hydrostatic pressure on the strucural, elastic and electronic properties of (B3) boron phosphide, using the pseudopotential plane-wave method (PP-PW) based on density functional theory within the Teter and Pade exchange-correlation functional form of the local density approximation (LDA). The lattice parameter, molecular and crystal densities, near-neighbour distances, independent elastic constant, bulk modulus, shear modulus, anisotropy factor and energy bandgaps of (B3) BP under high pressure are presented. The results showed a phase transition pressure from the zinc blende to rock-salt phase at around 1.56 Mbar, which is in good agreement with the theoretical data reported in the literature.

  4. Exact Solutions of Atmospheric (2+1)-Dimensional Nonlinear Incompressible Non-hydrostatic Boussinesq Equations

    Science.gov (United States)

    Liu, Ping; Wang, Ya-Xiong; Ren, Bo; Li, Jin-Hua

    2016-12-01

    Exact solutions of the atmospheric (2+1)-dimensional nonlinear incompressible non-hydrostatic Boussinesq (INHB) equations are researched by Combining function expansion and symmetry method. By function expansion, several expansion coefficient equations are derived. Symmetries and similarity solutions are researched in order to obtain exact solutions of the INHB equations. Three types of symmetry reduction equations and similarity solutions for the expansion coefficient equations are proposed. Non-traveling wave solutions for the INHB equations are obtained by symmetries of the expansion coefficient equations. Making traveling wave transformations on expansion coefficient equations, we demonstrate some traveling wave solutions of the INHB equations. The evolutions on the wind velocities, temperature perturbation and pressure perturbation are demonstrated by figures, which demonstrate the periodic evolutions with time and space. Supported by the National Natural Science Foundation of China under Grant Nos. 11305031 and 11305106, and Training Programme Foundation for Outstanding Young Teachers in Higher Education Institutions of Guangdong Province under Grant No. Yq2013205

  5. Control of electronic properties of organic conductors by hydrostatic and uniaxial compression

    Energy Technology Data Exchange (ETDEWEB)

    Kagoshima, S.; Kondo, R.; Hirai, H.; Shibata, T.; Kaga, Y. [Tokyo Univ. (Japan). Dept. of Basic Science; Maesato, M. [Kyoto Univ. (Japan). Dept. of Chemistry

    2001-01-01

    We developed the uniaxial strain method to artificially control the electronic properties of organic conductors by reducing the intermolecular distance along a desired direction without changing those along others. Using this method, we were able to cause and enhance superconductivity in two-dimensional organic conductors, {alpha}-(BEDT-TTF){sub 2}KHg(SCN){sub 4} and its isostructural compound having NH{sub 4} instead of K. We found that these two compounds show essentially the same properties if their lattice parameters are appropriately reduced by the uniaxial strain method, although they show quite different properties under ambient and hydrostatic pressures. In the one-dimensional organic superconductor (TMTSF){sub 2}PF{sub 6}, we found a novel result that is contradictory to the current interpretation for the suppression of spin density waves under pressures. (orig.)

  6. Enhancing the thermal stability of inulin fructotransferase with high hydrostatic pressure.

    Science.gov (United States)

    Li, Yungao; Miao, Ming; Liu, Miao; Chen, Xiangyin; Jiang, Bo; Feng, Biao

    2015-03-01

    The thermal stability of inulin fructotransferase (IFTase) subjected to high hydrostatic pressure (HHP) was studied. The value of inactivation rate of IFTase in the range of 70-80°C decreased under the pressure of 100 or 200 MPa, indicating that the thermostability of IFTase under high temperature was enhanced by HHP. Far-UV CD and fluorescence spectra showed that HHP impeded the unfolding of the conformation of IFTase under high temperature, reflecting the antagonistic effect between temperature and pressure on IFTase. The new intramolecular disulfide bonds in IFTase were formed under a combination of HHP and high temperature. These bonds might be related to the stabilization of IFTase at high temperature. All the above results suggested that HHP had the protective effect on IFTase against high temperature.

  7. Adaptive Laboratory Evolution of Escherichia coli K-12 MG1655 for Growth at High Hydrostatic Pressure

    Directory of Open Access Journals (Sweden)

    Angeliki eMarietou

    2015-01-01

    Full Text Available Much of microbial life on Earth grows and reproduces under the elevated hydrostatic pressure conditions that exist in deep-ocean and deep-subsurface environments. In this study adaptive laboratory evolution (ALE experiments were conducted to investigate the possible modification of the piezosensitive Escherichia coli for improved growth at high pressure. After approximately 500 generations of selection, a strain was isolated that acquired the ability to grow at pressure non-permissive for the parental strain. Remarkably, this strain displayed growth properties and changes in the proportion and regulation of unsaturated fatty acids that indicated the acquisition of multiple piezotolerant properties. These changes developed concomitantly with a change in the gene encoding the acyl carrier protein, which is required for fatty acid synthesis.

  8. Fiber optic sensor for hydrostatic pressure and temperature measurement in riverbanks monitoring

    Science.gov (United States)

    Schenato, Luca; Aneesh, Rajendran; Palmieri, Luca; Galtarossa, Andrea; Pasuto, Alessandro

    2016-08-01

    An optical fiber sensor for the simultaneous measurement of hydrostatic pressure and temperature in soil embankments is presented. It exploits the differential strain induced on a fiber in a dual-chamber case, constituting the sensor body. The strain, either induced by the pressure or by the temperature, is optically measured by means of coherent frequency domain reflectometry and variations induced by the two physical phenomena are discriminated because of the different behavior of the two chambers. Characterization of the sensor is presented and discussed. The prototype shows promising performance: temperature and pressure sensitivities are approximately -7 GHz/°C and -3.2 GHz/kPa, respectively, with accuracies of 0.5 °C and 0.3 kPa.

  9. Determination of stellar parameters of C-rich hydrostatic stars from spectro-interferometric observations

    CERN Document Server

    Paladini, C; Aringer, B; Hron, J; Reegen, P; Davis, C J; Lebzelter, T

    2011-01-01

    Giant stars, and especially C-rich giants, contribute significantly to the chemical enrichment of galaxies. The determination of precise parameters for these stars is a necessary prerequisite for a proper implementation of this evolutionary phase in the models of galaxies. Infrared interferometry opened new horizons in the study of the stellar parameters of giant stars, and provided new important constraints for the atmospheric and evolutionary models.We aim to determine which stellar parameters can be constrained by using infrared interferometry and spectroscopy, in the case of C-stars what is the precision which can be achieved and what are the limitations. For this purpose we obtained new infrared spectra and combined them with unpublished interferometric measurements for five mildly variable carbon-rich asymptotic giant branch stars. The observations were compared with a large grid of hydrostatic model atmospheres and with new isochrones which include the predictions of the thermally pulsing phase. For th...

  10. Effect of the hydrostatic pressure on otolith growth of early juveniles of Nile tilapia Oreochromis niloticus.

    Science.gov (United States)

    Correia, A T; Coimbra, A M; Damasceno-Oliveira, A

    2012-07-01

    Nile tilapia Oreochromis niloticus early juveniles were maintained for 2 weeks in a pressurized system under a controlled photoperiod, at constant salinity and temperature. Groups of fish were exposed to one of three absolute hydrostatic pressure (HP) regimes: (1) a constant normal atmospheric pressure (100 kPa), (2) a constant 40 m pressure (500 kPa) or (3) a semi-diurnal cyclic vertical migration (100-500 kPa). No significant differences were detected in otolith size and incremental periodicity among the three HP treatments, suggesting that HP does not affect otolith growth of early juveniles O. niloticus. © 2012 The Authors. Journal of Fish Biology © 2012 The Fisheries Society of the British Isles.

  11. Numerical and Experimental Investigation of the Hydrostatic Performance of Fibre Reinforced Tubes

    Science.gov (United States)

    Pavlopoulou, S.; Roy, S. S.; Gautam, M.; Bradshaw, L.; Potluri, P.

    2017-04-01

    The increasing demands in subsea industry such as oil and gas, led to a rapidly growing need for the use of advanced, high performance, lightweight materials such as composite materials. E-glass fibre laminated pre-preg, filament wound and braided tubes were tested to destruction under hydrostatic external pressure in order to study their buckling and crushing behaviour. Different fibre architectures and wind angles were tested at a range of wall thicknesses highlighting the advantage that hoop reinforcement offers. The experimental results were compared with theoretical predictions obtained from classic laminate theory and finite element analysis (ABAQUS) based on the principal that the predominant failure mode was buckling. SEM analysis was further performed to investigate the resulting failure mechanisms, indicating that the failure mechanisms can be more complex with a variety of observed modes taking place such as fibre fracture, delamination and fibre-matrix interface failure.

  12. Influence of hydrostatic pressure on superconducting properties of niobium thin film

    Energy Technology Data Exchange (ETDEWEB)

    Pristáš, Gabriel; Gabáni, Slavomír; Gažo, Emil [Centre of Low Temperature Physics, Institute of Experimental Physics, Slovak Academy of Sciences, Watsonova 47, 040 01 Košice (Slovakia); Komanický, Vladimír; Orendáč, Matúš [Centre of Low Temperature Physics, Faculty of Science, P. J. Šafárik University, Park Angelinum 9, SK-04154 Košice (Slovakia); You, Hoydoo [Materials Science Division, Argonne National Laboratory, Argonne, IL 60439 (United States)

    2014-04-01

    We have studied superconducting properties of niobium thin films under hydrostatic pressures up to 3 GPa. The films with thickness of 100 nm were prepared in the high vacuum DC magnetron sputtering system (with critical temperature TC = 8.95 K at ambient pressure). The produced high quality films have been characterized using electrical resistivity and magnetization measurements, X-ray diffraction, and atomic force microscope imaging. We have observed increase of TC with increasing value of applied pressure (dTC/dp = 73 mK/GPa) up to 3 GPa. This observation is different to pressure effect observed on bulk sample of Nb. In this paper we are discussing the origin of this discrepancy. - Highlights: • We have studied superconducting properties of niobium thin films under pressure. • The 100 nm thick films were prepared in DC magnetron sputtering system. • We have observed different behavior of T{sub C} for thin film and for bulk sample.

  13. Effects of Abscisic Acid and of Hydrostatic Pressure Gradient on Water Movement through Excised Sunflower Roots.

    Science.gov (United States)

    Glinka, Z

    1977-05-01

    The effect of abscisic acid on the exudation rate from decapitated roots of sunflower plants (Helianthus annuus L.) was investigated in the presence and absence of an imposed hydrostatic pressure gradient. The magnitude of the abscisic acid effect was constant even when suctions up to 60 cm Hg were applied to the cut stumps.When roots were bathed in a THO-labeled nutrient solution, the course of the appearance of radioactivity in the exudate, expressed as a function of exudate volume, was not affected by abscisic acid treatment but was strongly speeded up by applying suction.The implications of those findings with regard to the water pathway through the root and the location of the abscisic acid effect are discussed.

  14. Dynamic behavior of nano-voids in magnesium under hydrostatic tensile stress

    Science.gov (United States)

    Ponga, Mauricio; Ramabathiran, Amuthan A.; Bhattacharya, Kaushik; Ortiz, Michael

    2016-08-01

    We investigate the mechanisms responsible for nano-void growth in single crystal magnesium under dynamic hydrostatic tensile stress. A key conclusion derived from our study is that there is no secondary strain hardening near the nano-void. This behavior, which is in remarkable contrast to face-centered cubic and body-centered cubic materials, greatly limits the peak stress and explains the relatively lower spall strength of magnesium. The lack of secondary strain hardening is due to the fact that pyramidal dislocations do not interact with basal or prismatic dislocations. Our analysis also shows that for loads applied at moderate strain rates (\\overset{\\centerdot}{ɛ} ≤slant {{10}6} s-1) the peak stress, dislocation velocity and temperature distribution converge asymptotically. However at very high strain rates (\\overset{\\centerdot}{ɛ} ≥slant {{10}8} s-1), there is a sharp transition in these quantities.

  15. Sensitivity analysis of size effect on the performance of hydrostatic bearing

    Directory of Open Access Journals (Sweden)

    Dongju Chen

    2016-01-01

    Full Text Available For size effect on solid-liquid interface of hydrostatic bearing oil film gap flow in two-dimension, fluid dynamic method is applied to investigate the influence of size effect on bearing capacity, dynamic stiffness and other performances. With the consideration of size effect, Reynolds equation is modified by adopting velocity slip boundary condition into Reynolds equation. The sensitivity factors are used to make a quantitative and qualitative analysis. Numerical simulation results show that size effect will affect bearing performances to a certain degree and the effect curve of size effect on bearing performances are given. The four maximum oil film pressures reduce with the increase of slip length. The maximum sensitivity of bearing capacity is 81.94%.

  16. Modification of the SOI-like structures by annealing under high hydrostatic pressure

    Energy Technology Data Exchange (ETDEWEB)

    Surma, B.; Misiuk, A.; Haertwig, J.; Wnuk, A.; Bukowski, A.; Antonova, I.V

    2004-01-14

    The effect of enhanced hydrostatic pressure during annealing (HP-HT treatment) on creation/transformation of SiO{sub 2} in silicon implanted with oxygen (Si:O, oxygen doses 1x10{sup 14}-1x10{sup 16} cm{sup -2}) was studied by infrared absorption, photoluminescence and X-ray (synchrotron) methods. The redistribution of oxygen atoms at HP-HT in the Si:O structures, prepared by implantation with low doses (down to 1x10{sup 14} cm{sup -2}) of oxygen ions, leads to generation of separated clusters having the structure of a SiO{sub 2-x} network. Enhanced HP stimulates the creation of these clusters. A qualitative explanation of presented results, stressing the role of vacancies in the process of oxygen atoms agglomeration and the influence of compressive stress on the concentration of vacancies, is proposed.

  17. A HIGHER-ORDER NON-HYDROSTATIC MODEL FOR SIMULATING WAVE PROPAGATION OVER IRREGULAR BOTTOMS

    Institute of Scientific and Technical Information of China (English)

    AI Cong-fang; XING Yah; JIN Sheng

    2011-01-01

    A higher-order non-hydrostatic model is developed to simulate the wave propagation over irregular bottoms based on a vertical boundary-fitted coordinate system.In the model,an explicit projection method is adopted to solve the unsteady Euler equations.Advection terms are integrated explicitly with the MacCormack's scheme,with a second-order accuracy in both space and time.Two classical examples of surface wave propagation are used to demonstrate the capability of the model.It is found that the model with only two vertical layers could accurately simulate the motion of waves,including wave shoaling,nonlinearity,dispersion,refraction,and diffraction phenomena.

  18. Numerical and Experimental Investigation of the Hydrostatic Performance of Fibre Reinforced Tubes

    Science.gov (United States)

    Pavlopoulou, S.; Roy, S. S.; Gautam, M.; Bradshaw, L.; Potluri, P.

    2016-12-01

    The increasing demands in subsea industry such as oil and gas, led to a rapidly growing need for the use of advanced, high performance, lightweight materials such as composite materials. E-glass fibre laminated pre-preg, filament wound and braided tubes were tested to destruction under hydrostatic external pressure in order to study their buckling and crushing behaviour. Different fibre architectures and wind angles were tested at a range of wall thicknesses highlighting the advantage that hoop reinforcement offers. The experimental results were compared with theoretical predictions obtained from classic laminate theory and finite element analysis (ABAQUS) based on the principal that the predominant failure mode was buckling. SEM analysis was further performed to investigate the resulting failure mechanisms, indicating that the failure mechanisms can be more complex with a variety of observed modes taking place such as fibre fracture, delamination and fibre-matrix interface failure.

  19. A Petascale Non-Hydrostatic Atmospheric Dynamical Core in the HOMME Framework

    Energy Technology Data Exchange (ETDEWEB)

    Tufo, Henry [Univ. of Colorado, Boulder, CO (United States)

    2015-09-15

    The High-Order Method Modeling Environment (HOMME) is a framework for building scalable, conserva- tive atmospheric models for climate simulation and general atmospheric-modeling applications. Its spatial discretizations are based on Spectral-Element (SE) and Discontinuous Galerkin (DG) methods. These are local methods employing high-order accurate spectral basis-functions that have been shown to perform well on massively parallel supercomputers at any resolution and scale particularly well at high resolutions. HOMME provides the framework upon which the CAM-SE community atmosphere model dynamical-core is constructed. In its current incarnation, CAM-SE employs the hydrostatic primitive-equations (PE) of motion, which limits its resolution to simulations coarser than 0.1 per grid cell. The primary objective of this project is to remove this resolution limitation by providing HOMME with the capabilities needed to build nonhydrostatic models that solve the compressible Euler/Navier-Stokes equations.

  20. A Method of Upgrading a Hydrostatic Model to a Nonhydrostatic Model

    Directory of Open Access Journals (Sweden)

    Chi-Sann Liou

    2009-01-01

    Full Text Available As the sigma-p coordinate under hydrostatic approximation can be interpreted as the mass coordinate with out the hydro static approximation, we propose a method that up grades a hydro static model to a nonhydrostatic model with relatively less effort. The method adds to the primitive equations the extra terms omitted by the hydro static approximation and two prognostic equations for vertical speed w and nonhydrostatic part pres sure p'. With properly formulated governing equations, at each time step, the dynamic part of the model is first integrated as that for the original hydro static model and then nonhydrostatic contributions are added as corrections to the hydro static solutions. In applying physical parameterizations after the dynamic part integration, all physics pack ages of the original hydro static model can be directly used in the nonhydrostatic model, since the up graded nonhydrostatic model shares the same vertical coordinates with the original hydro static model. In this way, the majority codes of the nonhydrostatic model come from the original hydro static model. The extra codes are only needed for the calculation additional to the primitive equations. In order to handle sound waves, we use smaller time steps in the nonhydrostatic part dynamic time integration with a split-explicit scheme for horizontal momentum and temperature and a semi-implicit scheme for w and p'. Simulations of 2-dimensional mountain waves and density flows associated with a cold bubble have been used to test the method. The idealized case tests demonstrate that the pro posed method realistically simulates the nonhydrostatic effects on different atmospheric circulations that are revealed in the oretical solutions and simulations from other nonhydrostatic models. This method can be used in upgrading any global or mesoscale models from a hydrostatic to nonhydrostatic model.

  1. Feedback Regulation of Intracellular Hydrostatic Pressure in Surface Cells of the Lens.

    Science.gov (United States)

    Gao, Junyuan; Sun, Xiurong; White, Thomas W; Delamere, Nicholas A; Mathias, Richard T

    2015-11-03

    In wild-type lenses from various species, an intracellular hydrostatic pressure gradient goes from ∼340 mmHg in central fiber cells to 0 mmHg in surface cells. This gradient drives a center-to-surface flow of intracellular fluid. In lenses in which gap-junction coupling is increased, the central pressure is lower, whereas if gap-junction coupling is reduced, the central pressure is higher but surface pressure is always zero. Recently, we found that surface cell pressure was elevated in PTEN null lenses. This suggested disruption of a feedback control system that normally maintained zero surface cell pressure. Our purpose in this study was to investigate and characterize this feedback control system. We measured intracellular hydrostatic pressures in mouse lenses using a microelectrode/manometer-based system. We found that all feedback went through transport by the Na/K ATPase, which adjusted surface cell osmolarity such that pressure was maintained at zero. We traced the regulation of Na/K ATPase activity back to either TRPV4, which sensed positive pressure and stimulated activity, or TRPV1, which sensed negative pressure and inhibited activity. The inhibitory effect of TRPV1 on Na/K pumps was shown to signal through activation of the PI3K/AKT axis. The stimulatory effect of TRPV4 was shown in previous studies to go through a different signal transduction path. Thus, there is a local two-legged feedback control system for pressure in lens surface cells. The surface pressure provides a pedestal on which the pressure gradient sits, so surface pressure determines the absolute value of pressure at each radial location. We speculate that the absolute value of intracellular pressure may set the radial gradient in the refractive index, which is essential for visual acuity.

  2. Effects of high hydrostatic pressure on bacterial growth on human ossicles explanted from cholesteatoma patients.

    Science.gov (United States)

    Dommerich, Steffen; Frickmann, Hagen; Ostwald, Jürgen; Lindner, Tobias; Zautner, Andreas Erich; Arndt, Kathleen; Pau, Hans Wilhelm; Podbielski, Andreas

    2012-01-01

    High hydrostatic pressure (HHP) treatment can eliminate cholesteatoma cells from explanted human ossicles prior to re-insertion. We analyzed the effects of HHP treatment on the microbial flora on ossicles and on the planktonic and biofilm states of selected isolates. Twenty-six ossicles were explanted from cholesteatoma patients. Five ossicles were directly analyzed for microbial growth without further treatment. Fifteen ossicles were cut into two pieces. One piece was exposed to HHP of 350 MPa for 10 minutes. Both the treated and untreated (control) pieces were then assessed semi-quantitatively. Three ossicles were cut into two pieces and exposed to identical pressure conditions with or without the addition of one of two different combinations of antibiotics to the medium. Differential effects of 10-minute in vitro exposure of planktonic and biofilm bacteria to pressures of 100 MPa, 250 MPa, 400 MPa and 540 MPa in isotonic and hypotonic media were analyzed using two patient isolates of Staphylococcus epidermidis and Neisseria subflava. Bacterial cell inactivation and biofilm destruction were assessed by colony counting and electron microscopy. A variety of microorganisms were isolated from the ossicles. Irrespective of the medium, HHP treatment at 350 MPa for 10 minutes led to satisfying but incomplete inactivation especially of gram-negative bacteria. The addition of antibiotics increased the efficacy of elimination. A comparison of HHP treatment of planktonic and biofilm cells showed that the effects of HPP were reduced by about one decadic logarithmic unit when HPP was applied to biofilms. High hydrostatic pressure conditions that are suitable to inactivate cholesteatoma cells fail to completely sterilize ossicles even if antibiotics are added. As a result of the reduced microbial load and the viability loss of surviving bacteria, however, there is a lower risk of re-infection after re-insertion.

  3. DYNAMICO, an icosahedral hydrostatic dynamical core designed for consistency and versatility

    Directory of Open Access Journals (Sweden)

    T. Dubos

    2015-02-01

    Full Text Available The design of the icosahedral dynamical core DYNAMICO is presented. DYNAMICO solves the multi-layer rotating shallow-water equations, a compressible variant of the same equivalent to a discretization of the hydrostatic primitive equations in a Lagrangian vertical coordinate, and the primitive equations in a hybrid mass-based vertical coordinate. The common Hamiltonian structure of these sets of equations is exploited to formulate energy-conserving spatial discretizations in a unified way. The horizontal mesh is a quasi-uniform icosahedral C-grid obtained by subdivision of a regular icosahedron. Control volumes for mass, tracers and entropy/potential temperature are the hexagonal cells of the Voronoi mesh to avoid the fast numerical modes of the triangular C-grid. The horizontal discretization is that of Ringler et al. (2010, whose discrete quasi-Hamiltonian structure is identified. The prognostic variables are arranged vertically on a Lorenz grid with all thermodynamical variables collocated with mass. The vertical discretization is obtained from the three-dimensional Hamiltonian formulation. Tracers are transported using a second-order finite volume scheme with slope limiting for positivity. Explicit Runge–Kutta time integration is used for dynamics and forward-in-time integration with horizontal/vertical splitting is used for tracers. Most of the model code is common to the three sets of equations solved, making it easier to develop and validate each piece of the model separately. Representative three-dimensional test cases are run and analyzed, showing correctness of the model. The design permits to consider several extensions in the near future, from higher-order transport to more general dynamics, especially deep-atmosphere and non-hydrostatic equations.

  4. The NCEP Eulerian Non-hydrostatic Multi-scale Model (NMMB)

    Science.gov (United States)

    Janjic, Z.; Vasic, R.; Djurdjevic, V.; Black, T.; Jovic, D.

    2014-12-01

    The unified Non-hydrostatic Multi-scale Model (NMMB) is being developed at the National Centers for Environmental Predictions. The model dynamics preserve a number of important properties of differential operators and conserve a variety of first order and quadratic quantities. The nonlinear dynamics is controlled by conserving energy and enstrophy in case of non-divergent flow. Over-specification of non-hydrostatic vertical velocity is avoided. The physical package was developed from the WRF NMM's physics, but other physics options are also available. The regional version of the NMMB is run operationally as the main deterministic North American short-range forecasting model (NAM) and in a number of other applications. The global NMMB also has been run over the last few years experimentally in order to assess its capabilities and develop it further. In terms of large scale metrics, the performance of the global NMMB in medium range weather forecasting has been generally comparable to that of other major medium range forecasting systems. Its computational efficiency satisfies and exceeds the current and projected operational requirements. Recently, the transition has started of the operational hurricane forecasting system HWRF from the WRF NMM dynamics to those of the NMMB. This system involves the use of a hierarchy of 2-way interactive telescoping moving nests. The work on developing a unified multi-scale physics package has continued. Extended range forecasts showed large sensitivity to the method for representing clouds. With the clouds represented by optical properties of their microphysics species, the results depend on the microphysics scheme used. Also, taking into account the impact of convective clouds remains a challenge with this approach. Numerous sensitivity studies of physical parameterizations and the dynamical core features have been carried out as well. Relevant results will be presented and discussed, including some results of recent idealized

  5. Low-Shapiro hydrostatic reconstruction technique for blood flow simulation in large arteries with varying geometrical and mechanical properties

    Science.gov (United States)

    Ghigo, A. R.; Delestre, O.; Fullana, J.-M.; Lagrée, P.-Y.

    2017-02-01

    The purpose of this work is to construct a simple, efficient and accurate well-balanced numerical scheme for one-dimensional (1D) blood flow in large arteries with varying geometrical and mechanical properties. As the steady states at rest are not relevant for blood flow, we construct two well-balanced hydrostatic reconstruction techniques designed to preserve low-Shapiro number steady states that may occur in large network simulations. The Shapiro number Sh = u / c is the equivalent of the Froude number for shallow water equations and the Mach number for compressible Euler equations. The first is the low-Shapiro hydrostatic reconstruction (HR-LS), which is a simple and efficient method, inspired from the hydrostatic reconstruction technique (HR). The second is the subsonic hydrostatic reconstruction (HR-S), adapted here to blood flow and designed to exactly preserve all subcritical steady states. We systematically compare HR, HR-LS and HR-S in a series of single artery and arterial network numerical tests designed to evaluate their well-balanced and wave-capturing properties. The results indicate that HR is not adapted to compute blood flow in large arteries as it is unable to capture wave reflections and transmissions when large variations of the arteries' geometrical and mechanical properties are considered. On the contrary, HR-S is exactly well-balanced and is the most accurate hydrostatic reconstruction technique. However, HR-LS is able to compute low-Shapiro number steady states as well as wave reflections and transmissions with satisfying accuracy and is simpler and computationally less expensive than HR-S. We therefore recommend using HR-LS for 1D blood flow simulations in large arterial network simulations.

  6. High hydrostatic pressure and biopreservation of dry-cured ham to meet the Food Safety Objectives for Listeria monocytogenes.

    Science.gov (United States)

    Hereu, Anna; Bover-Cid, Sara; Garriga, Margarita; Aymerich, Teresa

    2012-03-15

    This work aimed to evaluate the effect of nisin application (biopreservation) combined with high hydrostatic pressure processing (HHP) on the behavior of Listeria monocytogenes CTC1034 intentionally inoculated (at ca. 10(7)cells/g) onto the surface of ready-to-eat (RTE) sliced dry-cured ham. Two types of dry-cured ham, which had different water activities and fat contents were studied (a(w) of 0.92 and 14.25% fat and a(w) of 0.88 and 33.26% fat). Three batches were prepared for each type of product: (C) control, without nisin; (N) nisin directly applied (200 AU/cm(2)) and (F) nisin applied through active packaging, polyvinyl alcohol films with 200 AU/cm(2). Half of the samples were pressurized at 600 MPa for 5min. Counts of L. monocytogenes were periodically monitored throughout 60 days of storage at 8°C. The physico-chemical characteristics of the products enabled the survival of L. monocytogenes, but it was significantly reduced by the presence of nisin. The effect of biopreservation was greater when applied directly to the surface and in the product with lower water activity in comparison with the active packaging and the high water activity products, respectively. The immediate inactivation of L. monocytogenes by HHP ranged from 1.82 to 3.85 Log units, depending on the type of dry-cured ham. The lower the water activity, the less was the inactivation induced by HHP, both immediately and during storage. The reduction of L. monocytogenes immediately after HHP and during storage was more evident in batches with nisin applied directly to the surface of the product. The pathogen was not detected in some samples from day 5 of storage in the product with higher water activity. The effect of nisin applied through active packaging was lower than the direct application. The results of the present study indicated that HHP, as post-processing listericidal treatment, is more effective (both immediately and long term) than the use of nisin as an antimicrobial measure

  7. Application of high hydrostatic pressure to decontaminate green onions from Salmonella and Escherichia coli O157:H7.

    Science.gov (United States)

    Neetoo, Hudaa; Nekoozadeh, Sanaz; Jiang, Zheng; Chen, Haiqiang

    2011-10-01

    Consumption of fecally contaminated green onions has been implicated in several major outbreaks of foodborne illness. The objectives of this study were to investigate the survival and growth of Salmonella and Escherichia coli O157:H7 in green onions during storage and to assess the application of high hydrostatic pressure (HHP) to decontaminate green onions from both pathogens. Bacterial strains resistant to nalidixic acid and streptomycin were used to inoculate green onions at low (∼1logcfu/g) and high (∼2logcfu/g) inoculum levels which were then kept at 4 or 22°C for up to 14 days. Both pathogens grew to an average of 5-6logcfu/g during storage at 22°C and the bacterial populations were fairly stable during storage at 4°C. High-pressure processing of inoculated green onions in the un-wetted, wetted (briefly dipped in water) or soaked (immersed in water for 30min) conditions at 250-500MPa for 2min at 20°C reduced the population of Salmonella and E. coli O157:H7 by 0.6 to >5logcfu/g, depending on the pressure level and sample wetness state. The extent of pressure inactivation increased in the order of soaked>wetted>un-wetted state. The pressure sensitivity of the pathogens was also higher at elevated treatment temperatures. Overall, after pressure treatment at 400-450MPa (soaked) or 450-500MPa (wetted) for a retention time of 2min at 20-40°C, wild-type and antibiotic-resistant mutant strains of Salmonella and E. coli O157:H7 inoculated on green onions were undetectable immediately after treatment and throughout the 15-day storage at 4°C. The pressure treatments also had minimal adverse impact on most sensorial characteristics as well as on the instrumental color of chopped green onions. This study highlights the promising applications of HHP to minimally process green onions in order to alleviate the risks of Salmonella and E. coli O157:H7 infections associated with the consumption of this commodity.

  8. Application of Hydrostatic Leveling System in Metro Monitoring Measureme nt%浅谈静力水准系统在地铁监护测量中的应用

    Institute of Scientific and Technical Information of China (English)

    刘振宇; 孟庆来; 董爵兰

    2015-01-01

    This paper introduces the working principle and characteristics of hydrostatic leveling system , Combined with the successful experience of Shanghai Metro monitoring measurement , Introduces the application of interval of settlement monitoring of hydrostatic leveling system in Shanghai Rail Transit Line No .2 Xujingdong-Hongqiao train station , A combination of case analysis , Deformation monitoring for later similar projects provide a good reference .%介绍了静力水准测量系统的工作原理及其特点,结合上海地铁监护测量的成功经验,介绍了静力水准测量系统在上海市轨道交通2号线徐泾东-虹桥火车站区间沉降监测的应用,结合实例进行分析,为类似的变形监测项目提供了很好的借鉴作用。

  9. Application of RBF Neural Network in Prediction of Static Stiffness for Constant-Current Hydrostatic Bearings%RB F神经网络在恒流静压轴承静刚度预测中的应用

    Institute of Scientific and Technical Information of China (English)

    连黎明; 唐军

    2014-01-01

    通过对数控转台SKZT3500用恒流静压轴承进行特性分析,借助软件MATLAB7.1中神经网络工具箱,将RBF神经网络的理论和算法应用到恒流静压轴承静刚度预测中。经过对物理样机进行相关试验,把测量获得的样本数据用于对RBF神经网络进行训练和测试。结果表明,RBF神经网络能够较准确地预测恒流静压轴承的静刚度。%Through analysis of the characteristics of constant -current hydrostatic bearings for NC rotary table SKZT3500,the theory and arithmetic for the RBF neural network are applied to predict the static stiffness for the bear-ings by using neural network toolbox in MATLAB 7.1.The measured sample data is used to train and test the RBF neural network through experiment of physical prototype.The results show that the RBF neural network can accurately forecast the static stiffness of constant-current hydrostatic bearings.

  10. Synergistic and additive effects of hydrostatic pressure and growth factors on tissue formation.

    Directory of Open Access Journals (Sweden)

    Benjamin D Elder

    Full Text Available BACKGROUND: Hydrostatic pressure (HP is a significant factor in the function of many tissues, including cartilage, knee meniscus, temporomandibular joint disc, intervertebral disc, bone, bladder, and vasculature. Though studies have been performed in assessing the role of HP in tissue biochemistry, to the best of our knowledge, no studies have demonstrated enhanced mechanical properties from HP application in any tissue. METHODOLOGY/PRINCIPAL FINDINGS: The objective of this study was to determine the effects of hydrostatic pressure (HP, with and without growth factors, on the biomechanical and biochemical properties of engineered articular cartilage constructs, using a two-phased approach. In phase I, a 3x3 full-factorial design of HP magnitude (1, 5, 10 MPa and frequency (0, 0.1, 1 Hz was used, and the best two treatments were selected for use in phase II. Static HP at 5 MPa and 10 MPa resulted in significant 95% and 96% increases, respectively, in aggregate modulus (H(A, with corresponding increases in GAG content. These regimens also resulted in significant 101% and 92% increases in Young's modulus (E(Y, with corresponding increases in collagen content. Phase II employed a 3x3 full-factorial design of HP (no HP, 5 MPa static, 10 MPa static and growth factor application (no GF, BMP-2+IGF-I, TGF-beta1. The combination of 10 MPa static HP and TGF-beta1 treatment had an additive effect on both H(A and E(Y, as well as a synergistic effect on collagen content. This group demonstrated a 164% increase in H(A, a 231% increase in E(Y, an 85% increase in GAG/wet weight (WW, and a 173% increase in collagen/WW, relative to control. CONCLUSIONS/SIGNIFICANCE: To our knowledge, this is the first study to demonstrate increases in the biomechanical properties of tissue from pure HP application, using a cartilage model. Furthermore, it is the only study to demonstrate additive or synergistic effects between HP and growth factors on tissue functional properties

  11. Improvement of In Vitro Three-Dimensional Cartilage Regeneration by a Novel Hydrostatic Pressure Bioreactor.

    Science.gov (United States)

    Chen, Jie; Yuan, Zhaoyuan; Liu, Yu; Zheng, Rui; Dai, Yao; Tao, Ran; Xia, Huitang; Liu, Hairong; Zhang, Zhiyong; Zhang, Wenjie; Liu, Wei; Cao, Yilin; Zhou, Guangdong

    2016-11-07

    : In vitro three-dimensional (3D) cartilage regeneration is a promising strategy for repair of cartilage defects. However, inferior mechanical strength and tissue homogeneity greatly restricted its clinical translation. Simulation of mechanical stress through a bioreactor is an important approach for improving in vitro cartilage regeneration. The current study developed a hydrostatic pressure (HP) bioreactor based on a novel pressure-transmitting mode achieved by slight deformation of a flexible membrane in a completely sealed stainless steel device. The newly developed bioreactor efficiently avoided the potential risks of previously reported pressure-transmitting modes and simultaneously addressed a series of important issues, such as pressure scopes, culture chamber sizes, sealability, contamination control, and CO2 balance. The whole bioreactor system realized stable long-term (8 weeks) culture under high HP (5-10 MPa) without the problems of medium leakage and contamination. Furthermore, the results of in vitro 3D tissue culture based on a cartilage regeneration model revealed that HP provided by the newly developed bioreactor efficiently promoted in vitro 3D cartilage formation by improving its mechanical strength, thickness, and homogeneity. Detailed analysis in cell proliferation, cartilage matrix production, and cross-linking level of collagen macromolecules, as well as density and alignment of collagen fibers, further revealed the possible mechanisms that HP regulated in vitro cartilage regeneration. The current study provided a highly efficient and stable bioreactor system for improving in vitro 3D cartilage regeneration and thus will help to accelerate its clinical translation. Inferior mechanical strength and tissue homogeneity of in vitro engineered three-dimensional (3D) cartilage greatly restricted its clinical translation. The current study developed a hydrostatic pressure (HP) bioreactor based on a novel pressure-transmitting mode, which

  12. Amended Calculation and Application of Hydrostatic System of Constant Current Closed Hydrostatic Guideway%恒流闭式静压导轨静压系统修正计算法及应用

    Institute of Scientific and Technical Information of China (English)

    张晓毅

    2011-01-01

    Mechanical calculation combined with finite element analysis is used in amended calculation for the constant current closed hydrostatic guideway. Through this calculation, the deformation in the oil reservoir of hydrostatic guideway was gotten. Based on the equilibrium equation of correction system, technics parameters were modified so as to minimize the impact of rigid deformation that caused by the guideway's basic element in reduced load condition on the hydrostatic parameters. Practice proves that the accuracy of design can be improved by amended calculation.%恒流闭式静压导轨修正计算法是采用力学计算和有限元分析相结合的方式,得到静压导轨油腔处的变形,在修正系统平衡方程的基础上,修改工艺参数,减小导轨基础件在负载条件下的刚性变形对静压导轨参数的影响.实践证明,修正计算法能提高设计的精度.

  13. Temperature-compensated distributed hydrostatic pressure sensor with a thin-diameter polarization-maintaining photonic crystal fiber based on Brillouin dynamic gratings.

    Science.gov (United States)

    Teng, Lei; Zhang, Hongying; Dong, Yongkang; Zhou, Dengwang; Jiang, Taofei; Gao, Wei; Lu, Zhiwei; Chen, Liang; Bao, Xiaoyi

    2016-09-15

    A temperature-compensated distributed hydrostatic pressure sensor based on Brillouin dynamic gratings (BDGs) is proposed and demonstrated experimentally for the first time, to the best of our knowledge. The principle is to measure the hydrostatic pressure induced birefringence changes through exciting and probing the BDGs in a thin-diameter pure silica polarization-maintaining photonic crystal fiber. The temperature cross-talk to the hydrostatic pressure sensing can be compensated through measuring the temperature-induced Brillouin frequency shift (BFS) changes using Brillouin optical time-domain analysis. A distributed measurement of hydrostatic pressure is demonstrated experimentally using a 4-m sensing fiber, which has a high sensitivity, with a maximum measurement error less than 0.03 MPa at a 20-cm spatial resolution.

  14. Comparing hydrostatic-pressure- and epitaxial-strain-induced phase transitions in multiferroic PbNiO3 from first principles

    Science.gov (United States)

    Tian, Hao; Kuang, Xiao-Yu; Mao, Ai-Jie; Zhao, Hong-Jian; Li, Hui; Kuang, Fang-Guang

    2015-02-01

    First-principles calculations are performed to simulate hydrostatic pressure and misfit strain effect on PbNiO3 (PNO) material. Significant difference between hydrostatic pressure and misfit strain effect is discovered. That is (1) a hydrostatic-pressure-induced phase transition from a rhombohedral R3c phase to an orthorhombic Pnma phase emerges around 6 GPa; and (2) an epitaxial-strain-induced phase transition from a monoclinic Cc phase (the sequel to a monoclinic distortion from R3c) to an orthorhombic Pbnm phase occurs about -3.3% misfit strain. Besides, the behaviors of oxygen octahedra tilting, polarization and the magnetic ordering temperature TN have been found to be strikingly affected by the variation of hydrostatic pressure and misfit strain, respectively. Finally, origins of the induced phase transitions are revealed.

  15. Effect of hydrostatic pressure and magnetic field on electromagnetically induced transparency based nonlinear frequency conversion in quantum ring

    Science.gov (United States)

    Gumber, Sukirti; Gambhir, Monica; Jha, Pradip Kumar; Mohan, Man

    2016-10-01

    We study the combined effect of hydrostatic pressure and magnetic field on electromagnetically induced transparency in quantum ring. The high flexibility in size and shape of ring makes it possible to fabricate a nearly perfect two-dimensional quantum structure. We also explore the dependence of frequency conversion, measured in terms of third order nonlinear susceptibility χ(3) , on coupling field, hydrostatic pressure and magnetic field. Although, a dip in χ(3) is observed with the introduction of strong coupling field, it renders the ring structure transparent to generated wave thus effectively enhancing the output of nonlinear frequency conversion process. At a fixed coupling strength, the output can be further enhanced by increasing the magnetic field while it shows an inverse relationship with pressure. These parameters, being externally controlled, provide an easy handle to control the output of quantum ring which can be used as frequency converter in communication networks.

  16. Energy balance in the solar transition region. III - Helium emission in hydrostatic, constant-abundance models with diffusion

    Science.gov (United States)

    Fontenla, J. M.; Avrett, E. H.; Loeser, R.

    1993-01-01

    In our previous papers we described the mathematical formalism and the computed results for energy-balance hydrostatic models of the solar transition region. In this paper we discuss in some detail the limitations of the hydrostatic and one-dimensional assumptions used. Then we analyze the determination of helium emission when diffusion is included. We use transport coefficients estimated from kinetic theory to determine the helium departures from local ionization balance. We calculate the helium spectra for each of our models and evaluate the role of helium in the energy transport. Also, we investigate the effects of coronal illumination on the structure of the transition region and upper chromosphere, and show how coronal illumination affects various EUV lines and the He I 10830 A line. Comparing with both absolute intensities and detailed line profiles, we show that our models are consistent not only with the observed hydrogen spectra but also with the available helium spectra.

  17. Structural changes in single-walled carbon nanotubes under non-hydrostatic pressures: x-ray and Raman studies

    Energy Technology Data Exchange (ETDEWEB)

    Karmakar, Sukanta [Synchrotron Radiation Section, Bhabha Atomic Research Centre, Mumbai 400 085 (India); Sharma, Surinder M [Synchrotron Radiation Section, Bhabha Atomic Research Centre, Mumbai 400 085 (India); Teredesai, P V [Department of Physics, Indian Institute of Science, Bangalore 560 012 (India); Muthu, D V S [Department of Physics, Indian Institute of Science, Bangalore 560 012 (India); Govindaraj, A [Chemistry and Physics of Materials Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur Campus, Jakkur, Bangalore 560 064 (India); Sikka, S K [Synchrotron Radiation Section, Bhabha Atomic Research Centre, Mumbai 400 085 (India); Sood, A K [Department of Physics, Indian Institute of Science, Bangalore 560 012 (India)

    2003-10-01

    Using in situ x-ray diffraction and Raman scattering techniques, we have investigated the behaviour of single-walled carbon nanotubes bundles under non-hydrostatic pressures. It is seen that the diffraction line corresponding to the two-dimensional triangular lattice in the bundles is not reversible for pressures beyond 5-GPa, in sharp contrast to earlier results under hydrostatic pressure conditions. Most interestingly, radial breathing and tangential Raman modes of the pressure-cycled samples from 21 and 30-GPa match very well with those of the starting sample. Raman and x-ray results put together clearly suggest that the ordering of tubes in the bundles is only marginally regained with a very short coherence length on decompression.

  18. Simultaneous influence of hydrostatic pressure and temperature on diamagnetic susceptibility of impurity doped quantum dots under the aegis of noise

    Science.gov (United States)

    Saha, Surajit; Ganguly, Jayanta; Bera, Aindrila; Ghosh, Manas

    2016-11-01

    We explore the diamagnetic susceptibility (DMS) of impurity doped quantum dot (QD) in presence of Gaussian white noise and under the combined influence of hydrostatic pressure (HP) and temperature (T). Presence of noise and also its mode of application discernibly affect the DMS profile. Application of HP and T invites greater delicacies in the observed DMS profiles. However, whereas the interplay between T and noise comes out to be extremely sensitive in fabricating the DMS profile, the pressure-noise interplay appears to be not that much noticeable. Under all conditions of temperature and pressure, the presence of multiplicative noise diminishes the value of DMS in comparison with that in presence of its additive analogue. The present study renders a deep insight into the remarkable role played by the interplay between noise, hydrostatic pressure and temperature in controlling the effective confinement imposed on the system which bears unquestionable relevance.

  19. Effect of high hydrostatic pressure and retrogradation treatments on structural and physicochemical properties of waxy wheat starch.

    Science.gov (United States)

    Hu, Xiao-Pei; Zhang, Bao; Jin, Zheng-Yu; Xu, Xue-Ming; Chen, Han-Qing

    2017-10-01

    In this study, the effects of high hydrostatic pressure and retrogradation (HHPR) treatments on in vitro digestibility, structural and physicochemical properties of waxy wheat starch were investigated. The waxy wheat starch slurries (10%, w/v) were treated with high hydrostatic pressures of 300, 400, 500, 600MPa at 20°C for 30min, respectively, and then retrograded at 4°C for 4d. The results indicated that the content of slowly digestible starch (SDS) in HHPR-treated starch samples increased with increasing pressure level, and it reached the maximum (31.12%) at 600MPa. HHPR treatment decreased the gelatinization temperatures, the gelatinization enthalpy, the relative crystallinity and the peak viscosity of the starch samples. Moreover, HHPR treatment destroyed the surface and interior structures of starch granules. These results suggest that the in vitro digestibility, physicochemical, and structural properties of waxy wheat starch are effectively modified by HHPR. Copyright © 2017 Elsevier Ltd. All rights reserved.

  20. Thermal effect on gravity waves in a compressible liquid layer over a solid half-space under initial hydrostatic stress

    Indian Academy of Sciences (India)

    Sushil Kumar Addy; Nil Ratan Chakraborty

    2005-02-01

    This paper deals with the effect of temperature on gravity waves in a compressible liquid layer over a solid half-space. It has been assumed that the liquid layer is under the action of gravity, while the solid half-space is under the influence of initial compressive hydrostatic stress. When the temperature of the half-space is altered, gravity waves propagate through the liquid layer along with sub-oceanic Rayleigh waves in the system. A new frequency equation has been derived here for gravity waves and sub-oceanic Rayleigh waves. It has been shown graphically that the phase velocity of gravity waves is influenced significantly by the initial compressive hydrostatic stress present in the solid half-space, for a particular value of the phase velocity of sub-oceanic Rayleigh waves and different coupling co-efficients of the temperature.

  1. Analysis of the Influence of Hydrostatic Stress on the Behaviour of an Adhesive in a Bonded Assembly

    OpenAIRE

    Cognard, J. Y.; Creac' Hcadec, R; Maurice, J.; Davies, Peter; Peleau, Michel; da Silva, L. F. M.

    2010-01-01

    Generally, adhesives are viscoelastic-plastic materials, for which the development of viscosity and plasticity varies depending on the type of adhesive and the stress state. Various models exist to represent the yield surface, or the so-called elastic limit, taking into account the two stress invariants, hydrostatic stress and von Mises equivalent stress. Moreover, to develop precise pressure-dependent constitutive models, it is necessary to have a large experimental database in order to accu...

  2. Experimental Analysis of the Influence of Hydrostatic Stress on the Behaviour of an Adhesive Using a Pressure Vessel

    OpenAIRE

    Cognard, J. Y.; Creac' Hcadec, R; da Silva, L. F. M.; Teixeira, F. G.; Davies, Peter; Peleau, Michel

    2011-01-01

    The modelling of the non-linear behaviour of ductile adhesives requires a large experimental database in order to represent accurately the strains which are strongly dependent on the tensile-shear loading combination. Various pressure-dependent constitutive models can be found in the literature, but only a few experimental results are available, for instance, to represent accurately the initial yield surface taking into account the two stress invariants, hydrostatic stress, and von Mises equi...

  3. Numerical Simulation on Process of Hydrostatic Extrusion for Tungsten Alloy through Concave Dies with Equal-strain Contour Lines

    Institute of Scientific and Technical Information of China (English)

    Zhaohui ZHANG; Fuchi WANG

    2001-01-01

    The numerical simulation to the process of hydrostatic extrusion for tungsten alloy through the concave dies with the equal-strain contour lines was carried out in this paper by the large deformation and elasto-plastic finite theory and ANSYS software. Both the pressure in the process of extrusion and the stress-strain distribution in the sample were analyzed, which founds a basis to the engineering application.

  4. Radiation-induced effects on the sensors of the Hydrostatic Leveling System for the LHC low-beta quadrupoles

    CERN Document Server

    Dimovasili, E; Mainaud-Durand, H; Marin, A; Ossart, F; Wijnands, Thijs

    2005-01-01

    The dose rate dependence of the Hydrostatic Leveling System (HLS) for the final focusing quadrupole magnets in the Large Hadron collider is discussed. At high dose rates, ionization of the air inside the sensors causes charge deposition and this perturbs the position measurement. A model is presented that corrects the HLS signal offset as a function of the dose rate. The model compares the HLS with condenser ionization chambers and in this note the results of the comparison are presented.

  5. Electronic phase transitions under hydrostatic pressure in LaMnO3 (111) bilayers sandwiched between LaAlO3

    KAUST Repository

    Tahini, Hassan Ali

    2016-01-13

    Using ab initio calculations, we investigate the effect of hydrostatic pressure on the electronic structure of LaMnO3 (111) bilayers sandwiched between LaAlO3. In the ideal heterostructure we observe Dirac cones at the Fermi energy. However, octahedral tiltings open a band gap and thus destroy the Dirac nature. We show that the effect of the tiltings can be suppressed by hydrostatic pressure from 40 GPa to 60 GPa. At higher pressure further phase transitions are encountered.

  6. Multi-layer hydrostatic equilibrium of planets and synchronous moons: theory and application to Ceres and to solar system moons

    Energy Technology Data Exchange (ETDEWEB)

    Tricarico, Pasquale [Planetary Science Institute, Tucson, AZ 85719 (United States)

    2014-02-20

    The hydrostatic equilibrium of multi-layer bodies lacks a satisfactory theoretical treatment despite its wide range of applicability. Here we show that by using the exact analytical potential of homogeneous ellipsoids we can obtain recursive analytical solutions and an exact numerical method for the hydrostatic equilibrium shape problem of multi-layer planets and synchronous moons. The recursive solutions rely on the series expansion of the potential in terms of the polar and equatorial shape eccentricities, while the numerical method uses the exact potential expression. These solutions can be used to infer the interior structure of planets and synchronous moons from their observed shape, rotation, and gravity. When applied to the dwarf planet Ceres, we show that it is most likely a differentiated body with an icy crust of equatorial thickness 30-90 km and a rocky core of density 2.4-3.1 g cm{sup –3}. For synchronous moons, we show that the J {sub 2}/C {sub 22} ≅ 10/3 and the (b – c)/(a – c) ≅ 1/4 ratios have significant corrections of order Ω{sup 2}/(πGρ), with important implications for how their gravitational coefficients are determined from fly-by radio science data and for how we assess their hydrostatic equilibrium state.

  7. Chemical and physical properties of aloe vera (Aloe barbadensis Miller gel stored after high hydrostatic pressure processing

    Directory of Open Access Journals (Sweden)

    Karina Di Scala

    2013-03-01

    Full Text Available The aim of this study was to evaluate the influence of high hydrostatic pressure (150, 250, 350, 450, and 550 MPa, applied for 5 minutes, on antioxidant capacity, total phenolic content, color, firmness, rehydration ratio, and water holding capacity of aloe vera gel stored for 60 days at 4 °C. The analyzed properties of the pressurized gel showed significant changes after the storage period. The highest value of total phenolic content was found at 550 MPa. However, a decrease in the antioxidant capacity was observed for all pressurized gel samples when compared to the control sample (p < 0.05. The smallest changes in product color were observed at pressure levels between 150 and 250 MP. The application of high hydrostatic pressure resulted in lower gel firmness, and the lowest value was found at 150 MPa (p < 0.05. On the other hand, the untreated sample showed a greater decrease in firmness, indicating that high pressure processing preserves this property. The application of high hydrostatic pressure exhibited modifications in the food matrix, which were evaluated in terms of rehydration ratio and water holding capacity.

  8. Limit of hydrostaticity in He and Ne determined by means of in situ single crystal x-ray diffraction

    Science.gov (United States)

    Kurnosov, Alexander; Trots, Dmitro; Boffa Balaran, Tiziana; Frost, Daniel

    2010-05-01

    An ultrahigh-intensity rotating anode FR-E+ SuperBright from Rigaku coupled with a Huber four circle diffractometer and VariMaxTM focusing optics has been used to determine accurate and precise lattice parameters of very small single-crystals in diamond anvil cells at pressures above 40 GPa in a conventional laboratory. The optics are focusing the X-ray beam at the sample position (800 mm from the aperture of the optics) to the spot of about 200 μm size with high resolution (as measured by the sharp reflections line widths). The intensities of reflections from any crystal are at least 30 times larger than those obtained for the same sample with a similar x-ray diffractometer equipped with a conventional x-ray tube. However, accurate and precise lattice parameters at high pressure can be obtained only under hydrostatic or at least very close to hydrostatic conditions in order to avoid broadening of the reflections. To test the quasi-hydrostatic limits of He and Ne we have therefore performed a study of single crystals of quartz up to amorphisation of the sample and MgO single crystals. The study of these materials has also the advantage of being able to obtain compare the pressure scale of these two very well known materials with that of the ruby scale which appears to be dependent on the pressure medium used.

  9. Molecular Mechanisms for High Hydrostatic Pressure-Induced Wing Mutagenesis in Drosophila melanogaster.

    Science.gov (United States)

    Wang, Hua; Wang, Kai; Xiao, Guanjun; Ma, Junfeng; Wang, Bingying; Shen, Sile; Fu, Xueqi; Zou, Guangtian; Zou, Bo

    2015-10-08

    Although High hydrostatic pressure (HHP) as an important physical and chemical tool has been increasingly applied to research of organism, the response mechanisms of organism to HHP have not been elucidated clearly thus far. To identify mutagenic mechanisms of HHP on organisms, here, we treated Drosophila melanogaster (D. melanogaster) eggs with HHP. Approximately 75% of the surviving flies showed significant morphological abnormalities from the egg to the adult stages compared with control flies (p melanogaster induced by HHP were used to investigate the mutagenic mechanisms of HHP on organism. Thus 285 differentially expressed genes associated with wing mutations were identified using Affymetrix Drosophila Genome Array 2.0 and verified with RT-PCR. We also compared wing development-related central genes in the mutant flies with control flies using DNA sequencing to show two point mutations in the vestigial (vg) gene. This study revealed the mutagenic mechanisms of HHP-induced mutagenesis in D. melanogaster and provided a new model for the study of evolution on organisms.

  10. Hydrostatic pressure induced three-dimensional Dirac semimetal in black phosphorus

    Science.gov (United States)

    Gong, Peng-Lai; Liu, Da-Yong; Yang, Kai-Shuai; Xiang, Zi-Ji; Chen, Xian-Hui; Zeng, Zhi; Shen, Shun-Qing; Zou, Liang-Jian

    2016-05-01

    We present the first-principles studies on the hydrostatic pressure effect of the electronic properties of black phosphorus. We show that the energy bands crossover around the critical pressure Pc=1.23 GPa; with increasing pressure, the band reversal occurs at the Z point and evolves into 4 twofold-degenerate Dirac cones around the Z point, suggesting that pressured black phosphorus is a 3D Dirac semimetal. With further increasing pressure the Dirac cones in the Γ -Z line move toward the Γ point and evolve into two hole-type Fermi pockets, and those in the Z -M lines move toward the M point and evolve into two tiny electron-type Fermi pockets, and a band above the Z -M line sinks below EF and contributes four electron-type pockets. A clear Lifshitz transition occurs at Pc from semiconductor to 3D Dirac semimetal. Such a 3D Dirac semimetal is protected by the nonsymmorphic space symmetry of bulk black phosphorus. These suggest the bright perspective of black phosphorus for optoelectronic and electronic devices due to its easy modulation by pressure.

  11. Morphological and physiological characterization of Listeria monocytogenes subjected to high hydrostatic pressure.

    Science.gov (United States)

    Ritz, M; Tholozan, J L; Federighi, M; Pilet, M F

    2001-05-01

    High hydrostatic pressure is a new food preservation technology known for its capacity to inactivate spoilage and pathogenic microorganisms. That inactivation is usually assessed by the number of colonies growing on solid media after treatment. Under normal conditions the method does not permit recovery of damaged cells and may underestimate the number of cells that will remain viable and grow after a few days in high-pressure-processed foodstuffs. This study investigated the damage inflicted on Listeria monocytogenes cells treated by high pressure for 10 min at 400 MPa in pH 5.6 citrate buffer. Under these conditions, no cell growth occurred after 48 h on plate count agar. Scanning electron microscopy, light scattering by flow cytometry, and cell volume measurements were compared to evaluate the morphological changes in cells after pressurization. All these methods revealed that cellular morphology was not really affected. Esterase activity, as assessed either by enzymatic activity assays or by carboxy fluorescein diacetate fluorescence monitored by flow cytometry, was dramatically lowered, but not totally obliterated, under the effects of treatment. The measurement of propidium iodide uptake followed by flow cytometry demonstrated that membrane integrity was preserved in a small part of the population, although the membrane potential measured by analytical methods or evaluated by oxonol uptake was reduced from -86 to -5 mV. These results showed that such combined methods as fluorescent dyes monitored by flow cytometry and physiological activity measurements provide valuable indications of cellular viability.

  12. The effect of high hydrostatic pressure on black truffle (tuber melanosporum) flavour compounds

    Energy Technology Data Exchange (ETDEWEB)

    Verret, C; Ballestra, P; Cruz, C; Moueffak, A H E [Equipe de Recherche Agroalimentaire Perigourdine (ERAP) IUT de Perigueux Universite Bordeaux IV site universitaire F24019 Perigueux Cedex France (France); Pardon, P [Laboratoire d' analyses de l' Institut du pin Universite Bordeaux I France (France); Largeteau, A, E-mail: moueffak@u-bordeaux4.fr

    2008-07-15

    The effects of high hydrostatic pressure (HHP), at 4{sup 0}C or -18{sup 0}C, on black truffle flavour compounds, alteration enzymes (lipoxigenase (LOX), peroxidase (POD) and polyphenoloxidase (PPO)) and microbiological qualities were evaluated. The choosen analytes for this study are six alcohols, three aldehydes, one ketone and on sulfur component. The highest flavour stability was observed when samples were pressurized at 300 MPa / 4{sup 0}C / 10 min. All the treatments induced a drastic decrease of LOX activity and a slight decrease of POD activity. On the other hand, the PPO was not inactivated by pressurization at sub-zero (200 MPa / -18{sup 0}C / 10 min) and was strongly increased after the 300 MPa / 4{sup 0}C / 10 min treatment. Pressurization at 300 and 550 MPa lead to an almost complete Pseudomonas fluorescens reduction (6 and 6.5 log destruction, respectively) whereas pressurization at -18{sup 0}C (200MPa) allowed to obtain only 3 log reduction.

  13. A comparison of manual versus hydrostatic reduction in children with intussusception: Single-center experience

    Directory of Open Access Journals (Sweden)

    Servet Ocal

    2014-01-01

    Full Text Available Objective: In recent years several techniques have been recommended for intussusception treatment. In this study, an evaluation was made of intussusception cases that presented at our clinic and had reduction applied together with saline under ultrasonography (USG and cases, which were surgically treated. Patients and Methods: A retrospective evaluation was made of the records of 72 cases treated for a diagnosis of intussusception between January 2010 and July 2012. Patients were evaluated demographics, clinical presentation, management strategy, during the hospitalisation and outcome. Results: A total of 72 cases which consists of 44 male and 28 female with age range between 5 and 132 months were treated with a diagnosis of intussusception. USG was applied to all cases on initial presentation. As treatment, hydrostatic reduction (HR together with USG was applied to 47 cases. Of these, the HR was unsuccessful in 13 cases. Surgical treatment was applied to 38 cases. Of these cases, ileocolic intussusception was observed in 30 cases, ileoileal in seven cases and colocolic in one case. Meckel diverticulum was determined in five of these cases, polyps in two cases, lymphoma in two cases, lymph nodule in one case and 28 cases were observed to be idiopathic. There was no mortality in any case. Conclusion: HR together with USG is a safe technique in the treatment of intussusception, which also shortens the duration of hospitalisation and significantly reduces the treatment costs.

  14. Microbial diversity and adaptation to high hydrostatic pressure in deep-sea hydrothermal vents prokaryotes.

    Science.gov (United States)

    Jebbar, Mohamed; Franzetti, Bruno; Girard, Eric; Oger, Philippe

    2015-07-01

    Prokaryotes inhabiting in the deep sea vent ecosystem will thus experience harsh conditions of temperature, pH, salinity or high hydrostatic pressure (HHP) stress. Among the fifty-two piezophilic and piezotolerant prokaryotes isolated so far from different deep-sea environments, only fifteen (four Bacteria and eleven Archaea) that are true hyper/thermophiles and piezophiles have been isolated from deep-sea hydrothermal vents; these belong mainly to the Thermococcales order. Different strategies are used by microorganisms to thrive in deep-sea hydrothermal vents in which "extreme" physico-chemical conditions prevail and where non-adapted organisms cannot live, or even survive. HHP is known to impact the structure of several cellular components and functions, such as membrane fluidity, protein activity and structure. Physically the impact of pressure resembles a lowering of temperature, since it reinforces the structure of certain molecules, such as membrane lipids, and an increase in temperature, since it will also destabilize other structures, such as proteins. However, universal molecular signatures of HHP adaptation are not yet known and are still to be deciphered.

  15. Laparoscopy-assisted hydrostatic in situ reduction of intussusception: A reasonable alternative?

    Directory of Open Access Journals (Sweden)

    V. V. S. S. Chandrasekharam

    2011-01-01

    Full Text Available Aim: To evaluate an alternative way of reducing intussusceptions under laparoscopic guidance. Materials and Methods: This is a retrospective observational study of children who underwent laparoscopy-assisted hydrostatic in situ reduction of intussusceptions (LAHIRI. Under general anesthesia with laparoscopic vision, warm saline was infused into the rectum with a 16-18 F Foley catheter and a drip set till the intussusception was reduced. Results: Eleven patients [age 7.8 (±2.8 months] were operated over a period of 1 year. Ten (90.9% patients had ileocolic intussusception, which got completely reduced, but one (9% had ileo-ileocolic intusussception, in whom manual reduction by extending the subumbilical incision was required to reduce the ileoileal part. The mean duration of surgery was 38.5 (±6.6 min. No patient had bowel ischemia and there were no intra- or postoperative complications. Conclusions: LAHIRI appears to be an effective and safe technique in children. Specific advantages are that it is performed in a controlled environment in the operating room, avoids patient apprehension and discomfort, avoids bowel handling, provides a safe opportunity to create higher intraluminal pressure, ensures visual assessment of bowel vascularity and completeness of reduction.

  16. Pneumatic pressure bioreactor for cyclic hydrostatic stress application: mechanobiology effects on periodontal ligament cells.

    Science.gov (United States)

    Wenger, Karl H; El-Awady, Ahmed R; Messer, Regina L W; Sharawy, Mohamed M; White, Greg; Lapp, Carol A

    2011-10-01

    A bioreactor system was developed to provide high-amplitude cyclic hydrostatic compressive stress (cHSC) using compressed air mixed commercially as needed to create partial pressures of oxygen and carbon dioxide appropriate for the cells under investigation. Operating pressures as high as 300 psi are achievable in this system at cyclic speeds of up to 0.2 Hz. In this study, ligamentous fibroblasts from human periodontal ligaments (n = 6) were compressed on two consecutive days at 150 psi for 3 h each day, and the mRNA for families of extracellular matrix protein and protease isoforms was evaluated by real-time PCR array. Several integrins were significantly upregulated, most notably alpha-3 (6.4-fold), as was SPG7 (12.1-fold). Among the collagens, Col8a1 was highly upregulated at 53.5-fold, with Col6a1, Col6a2, and Col7a1 also significantly upregulated 4.4- to 8.5-fold. MMP-1 was the most affected at 122.9-fold upregulation. MMP-14 likewise increased 17.8-fold with slight reductions for the gelatinases and a significant increase of TIMP-2 at 5.8-fold. The development of this bioreactor system and its utility in characterizing periodontal ligament fibroblast mechanobiology in intermediate-term testing hold promise for better simulating the conditions of the musculoskeletal system and the large cyclic compressive stresses joints may experience in gait, exertion, and mastication.

  17. Validity of Hydrostatic Equilibrium in Galaxy Clusters from Cosmological Hydrodynamical Simulations

    CERN Document Server

    Suto, Daichi; Kitayama, Tetsu; Sasaki, Shin; Suto, Yasushi; Cen, Renyue

    2013-01-01

    We examine the validity of the hydrostatic equilibrium (HSE) assumption for galaxy clusters using one of the highest-resolution cosmological hydrodynamical simulations. We define and evaluate several effective mass terms corresponding to the Euler equations of the gas dynamics, and quantify the degree of the validity of HSE in terms of the mass estimate. We find that the mass estimated under the HSE assumption (the HSE mass) deviates from the true mass by up to ~ 30 %. This level of departure from HSE is consistent with the previous claims, but our physical interpretation is rather different. We demonstrate that the inertial term in the Euler equations makes a negligible contribution to the total mass, and the overall gravity of the cluster is balanced by the thermal gas pressure gradient and the gas acceleration term. Indeed the deviation from the HSE mass is well explained by the acceleration term at almost all radii. We also clarify the confusion of previous work due to the inappropriate application of the...

  18. The role of calcium signalling in the chondrogenic response of mesenchymal stem cells to hydrostatic pressure

    Directory of Open Access Journals (Sweden)

    AJ Steward

    2014-10-01

    Full Text Available The object of this study was to elucidate the role of Ca++ signalling in the chondrogenic response of mesenchymal stem cells (MSCs to hydrostatic pressure (HP. MSCs were seeded into agarose hydrogels, subjected to HP or kept in free swelling conditions, and were cultured either with or without pharmacological inhibitors of Ca++ mobility and downstream targets. Chelating free Ca++, inhibiting voltage-gated calcium channels, and depleting intracellular calcium storessuppressed the beneficial effect of HP on chondrogenesis, indicating that Ca++ mobility may play an important role in the mechanotransduction of HP. However, inhibition of stretch-activated calcium channels in the current experiment yielded similar results to the control group, suggesting that mechanotransduction of HP is distinct from loads that generate cell deformations. Inhibition of the downstream targets calmodulin, calmodulin kinase II, and calcineurin all knocked down the effect of HP on chondrogenesis, implicating these targets in MSCs response to HP. All of the pharmacological inhibitors that abolished the chondrogenic response to HP also maintained a punctate vimentin organisation in the presence of HP, as opposed to the mechanoresponsive groups where the vimentin structure became more diffuse. These results suggest that Ca++ signalling may transduce HP via vimentin adaptation to loading.

  19. The metastable state of nucleocapsids of enveloped viruses as probed by high hydrostatic pressure.

    Science.gov (United States)

    Gaspar, L P; Terezan, A F; Pinheiro, A S; Foguel, D; Rebello, M A; Silva, J L

    2001-03-09

    Enveloped viruses fuse their membranes with cellular membranes to transfer their genomes into cells at the beginning of infection. What is not clear, however, is the role of the envelope (lipid bilayer and glycoproteins) in the stability of the viral particle. To address this question, we compared the stability between enveloped and nucleocapsid particles of the alphavirus Mayaro using hydrostatic pressure and urea. The effects were monitored by intrinsic fluorescence, light scattering, and binding of fluorescent dyes, including bis(8-anilinonaphthalene-1-sulfonate) and ethidium bromide. Pressure caused a drastic dissociation of the nucleocapsids as determined by tryptophan fluorescence, light scattering, and gel filtration chromatography. Pressure-induced dissociation of the nucleocapsids was poorly reversible. In contrast, when the envelope was present, pressure effects were much less marked and were highly reversible. Binding of ethidium bromide occurred when nucleocapsids were dissociated under pressure, indicating exposure of the nucleic acid, whereas enveloped particles underwent no changes. Overall, our results demonstrate that removal of the envelope with the glycoproteins leads the particle to a metastable state and, during infection, may serve as the trigger for disassembly and delivery of the genome. The envelope acts as a "Trojan horse," gaining entry into the host cell to allow release of a metastable nucleocapsid prone to disassembly.

  20. High Hydrostatic Pressure Pretreatment of Whey Protein Isolates Improves Their Digestibility and Antioxidant Capacity

    Directory of Open Access Journals (Sweden)

    Michèle M. Iskandar

    2015-05-01

    Full Text Available Whey proteins have well-established antioxidant and anti-inflammatory bioactivities. High hydrostatic pressure processing of whey protein isolates increases their in vitro digestibility resulting in enhanced antioxidant and anti-inflammatory effects. This study compared the effects of different digestion protocols on the digestibility of pressurized (pWPI and native (nWPI whey protein isolates and the antioxidant and anti-inflammatory properties of the hydrolysates. The pepsin-pancreatin digestion protocol was modified to better simulate human digestion by adjusting temperature and pH conditions, incubation times, enzymes utilized, enzyme-to-substrate ratio and ultrafiltration membrane molecular weight cut-off. pWPI showed a significantly greater proteolysis rate and rate of peptide appearance regardless of digestion protocol. Both digestion methods generated a greater relative abundance of eluting peptides and the appearance of new peptide peaks in association with pWPI digestion in comparison to nWPI hydrolysates. Hydrolysates of pWPI from both digestion conditions showed enhanced ferric-reducing antioxidant power relative to nWPI hydrolysates. Likewise, pWPI hydrolysates from both digestion protocols showed similar enhanced antioxidant and anti-inflammatory effects in a respiratory epithelial cell line as compared to nWPI hydrolysates. These findings indicate that regardless of considerable variations of in vitro digestion protocols, pressurization of WPI leads to more efficient digestion that improves its antioxidant and anti-inflammatory properties.

  1. Retrogradation of Maize Starch after High Hydrostatic Pressure Gelation: Effect of Amylose Content and Depressurization Rate

    KAUST Repository

    Yang, Zhi

    2016-05-24

    High hydrostatic pressure (HHP) has been employed to gelatinize or physically modify starch dispersions. In this study, waxy maize starch, normal maize starch, and two high amylose content starch were processed by a HHP of the order of 600 MPa, at 25°C for 15min. The effect of HHP processing on the crystallization of maize starches with various amylose content during storage at 4°C was investigated. Crystallization kinetics of HHP treated starch gels were investigated using rheology and FTIR. The effect of crystallization on the mechanical properties of starch gel network were evaluated in terms of dynamic complex modulus (G*). The crystallization induced increase of short-range helices structures were investigated using FTIR. The pressure releasing rate does not affect the starch retrogradation behaviour. The rate and extent of retrogradation depends on the amylose content of amylose starch. The least retrogradation was observed in HHP treated waxy maize starch. The rate of retrogradation is higher for HHP treated high amylose maize starch than that of normal maize starch. A linear relationship between the extent of retrogradation (phase distribution) measured by FTIR and G* is proposed.

  2. The Enigmatic Dense Core L1451-mm: A First Hydrostatic Core Candidate

    Science.gov (United States)

    Pineda, Jaime E.; Goodman, A. A.; Arce, H. G.; Schnee, S.; Bourke, T.; Foster, J.; Robitaille, T.; Tanner, J.; Kauffmann, J.; Tafalla, M.; Caselli, P.; Anglada, G.

    2011-05-01

    We present the detection of a dust continuum source at 93GHz (CARMA) and 230GHz (SMA), and 12CO(2-1) emission (SMA) towards the L1451-mm dense core located in the Perseus Cloud. These detections suggest a compact object and an outflow where no point source is detected using Spitzer. An upper limit for the dense core bolometric luminosity of 0.07Lsun is obtained. We simultaneously model the broadband SED and the continuum visibilities, and the modeling confirms that a central source of heating is needed to explain the observations. It also shows that the data can be well fitted by a dense core with a YSO and disk, or by a dense core with a central First Hydrostatic Core (FHSC). Unfortunately, we are not able to rule out any of these two models, which produce similar fits. We also detect 12CO(2-1) emission with red- and blue-shifted emission suggesting the presence of a slow and poorly collimated outflow, in opposition to what is usually found towards young objects but in agreement with prediction from simulations of a FHSC. This presents the best candidate, so far, for a FHSC, an object that has been identified in simulations of collapsing dense cores. Whatever the true nature of the central object in L1451-mm, this core presents an excellent laboratory to study the earliest phases of star formation.

  3. Changes in microbial diversity of brined green asparagus upon treatment with high hydrostatic pressure.

    Science.gov (United States)

    Toledo Del Árbol, Julia; Pérez Pulido, Rubén; La Storia, Antonietta; Grande Burgos, Maria José; Lucas, Rosario; Ercolini, Danilo; Gálvez, Antonio

    2016-01-01

    The application of high hydrostatic pressure (HHP, 600MPa, 8 min) on brined green asparagus and the changes in bacterial diversity after treatments and during storage at 4 °C (30 days) or 22 °C (10 days) were studied. HHP treatments reduced viable cell counts by 3.6 log cycles. The residual surviving population did not increase during storage at 4 °C. However, bacterial counts significantly increased at 22 °C by day 3, leading to rapid spoilage. The microbiota of green asparagus was composed mainly by Proteobacteria (mainly Pantoea and Pseudomonas), followed by Firmicutes (mainly Lactococcus and Enterococcus) and to a less extent Bacteroidetes and Actinobacteria. During chill storage of untreated asparagus, the relative abundance of Proteobacteria as well as Enterococcus and Lactococcus decreased while Lactobacillus increased. During storage of untreated asparagus at 22 °C, the abundance of Bacteroidetes decreased while Proteobacteria increased during late storage. The HHP treatment determined a reduction of the Proteobacteria both early after treatment and during chill storage. In the HHP treated samples stored at 22 °C, the relative abundance of Pseudomonas rapidly decreased at day 1, with an increase of Bacteroidetes. This was followed by a marked increase in Enterobacteriaceae (Escherichia) simultaneously with increase in viable counts and spoilage. Results from the study indicate that the effect of HHP treatments on the viability ofmicrobial populations in foods also has an impact on the dynamics of microbial populations during the storage of the treated foods.

  4. Hydrostatic Simulation of Earth's Atmospheric Gas Using Multi-particle Collision Dynamics

    CERN Document Server

    Pattisahusiwa, Asis; Virid, Sparisoma

    2015-01-01

    Multi-particle collision dynamics (MPCD) is a mesoscopic simulation method to simulate fluid particle-like flows. MPCD has been widely used to simulate various problems in condensed matter. In this study, hydrostatic behavior of gas in the Earth's atmospheric layer is simulated by using MPCD method. The simulation is carried out by assuming the system under ideal state and is affected only by gravitational force. Gas particles are homogeneous and placed in 2D box. Interaction of the particles with the box is applied through implementation of boundary conditions (BC). Periodic BC is applied on the left and the right side, specular reflection on the top side, while bounce-back on the bottom side. Simulation program is executed in Arch Linux and running in notebook with processor Intel i5 @2700 MHz with 10 GB DDR3 RAM. The results show behaviors of the particles obey kinetic theory for ideal gas when gravitational acceleration value is proportional to the particle mass. Density distribution as a function of alti...

  5. Effects of High Hydrostatic Pressure on Water Absorption of Adzuki Beans

    Directory of Open Access Journals (Sweden)

    Shigeaki Ueno

    2015-05-01

    Full Text Available The effect of high hydrostatic pressure (HHP treatment on dried soybean, adzuki bean, and kintoki kidney bean, which are low-moisture-content cellular biological materials, was investigated from the viewpoint of water absorption. The samples were vacuum-packed with distilled water and pressurized at 200 MPa and 25 °C for 10 min. After the HHP treatment, time courses of the moisture contents of the samples were measured, and the dimensionless moisture contents were estimated. Water absorption in the case of soybean could be fitted well by a simple water diffusion model. High pressures were found to have negligible effects on water absorption into the cotyledon of soybean and kintoki kidney bean. A non-linear least square method based on the Weibull equation was applied for the adzuki beans, and the effective water diffusion coefficient was found to increase significantly from 8.6 × 10−13 to 6.7 × 10−10 m2/s after HHP treatment. Approximately 30% of the testa of the adzuki bean was damaged upon HHP treatment, which was comparable to the surface area of the testa in the partially peeled adzuki bean sample. Thus, HHP was confirmed to promote mass transfer to the cotyledon of legumes with a tight testa.

  6. Prediction of magnetic moment collapse in ZrFe{sub 2} under hydrostatic pressure

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Wenxu; Zhang, Wanli [State Key Laboratory of Electronic Thin Films and Integrated Devices, University of Electronic Science and Technology of China, Chengdu 610054 (China)

    2015-04-28

    Electronic structure and magnetic properties of ZrFe{sub 2} in the cubic Laves phase are investigated by calculations based on density functional theory. The magnetic moment decreases with the increase of the hydrostatic pressure in an unusual way: Two-step magnetic collapse is predicted. The first one is a continuous change from 1.53 μ{sub B}/Fe to 0.63 μ{sub B}/Fe at about 3.6 GPa, and the other is from 0.25 μ{sub B}/Fe to the nonmagnetic state at about 15 GPa in a first order manner under the local spin density approximation of the exchange correlation potential. A metastable state with intermediate spin moment about 0.15 μ{sub B}/Fe may exist before that. We understand this process by the changes of density of states during it. The magnetic moment decreases under the pressure in the vicinity of the experimental lattice constant with dlnm/dp=−0.038 GPa{sup −1}. The spontaneous volume magnetostriction is 3.6%, which is huge enough to find potential applications in magnetostriction actuators and sensors. We suggest that the Invar effect of this compound may be understood when considering the magnetic moment variation according to the magnetostrictive model of Invar.

  7. Energy balance in the solar transition region. I - Hydrostatic thermal models with ambipolar diffusion

    Science.gov (United States)

    Fontenla, J. M.; Avrett, E. H.; Loeser, R.

    1990-01-01

    The energy balance in the lower transition region is analyzed by constructing theoretical models which satisfy the energy balance constraint. The energy balance is achieved by balancing the radiative losses and the energy flowing downward from the corona. This energy flow is mainly in two forms: conductive heat flow and hydrogen ionization energy flow due to ambipolar diffusion. Hydrostatic equilibrium is assumed, and, in a first calculation, local mechanical heating and Joule heating are ignored. In a second model, some mechanical heating compatible with chromospheric energy-balance calculations is introduced. The models are computed for a partial non-LTE approach in which radiation departs strongly from LTE but particles depart from Maxwellian distributions only to first order. The results, which apply to cases where the magnetic field is either absent, or uniform and vertical, are compared with the observed Lyman lines and continuum from the average quiet sun. The approximate agreement suggests that this type of model can roughly explain the observed intensities in a physically meaningful way, assuming only a few free parameters specified as chromospheric boundary conditions.

  8. Structure-based modelling of hemocyanin allergenicity in squid and its response to high hydrostatic pressure

    Science.gov (United States)

    Zhang, Yifeng; Deng, Yun; Zhao, Yanyun

    2017-01-01

    The secondary, tertiary, and quaternary structures of squid hemocyanin (Hc) were characterised, and the relationship between Hc structure and allergenicity responses to high hydrostatic pressure (HHP) was modelled. The Hc allergenicity varied with its protein structure. Electrophoresis analysis revealed that HHP treatment significantly decreased the band intensity of Hc when increasing pressure from 200 and 400 MPa to 600 MPa. The protein structure analysis of squid Hc showed that while HHP treatment decreased the α-helix content, free sulfhydryl content, and Rg, it increased the random coil content, surface hydrophobicity index (Ho), Guinier aggregation number (〈Nagg〉G) and average aggregation number (〈Nagg〉Q). The α-helix and random coil contents of the 600 MPa treated samples were 23.67% and 37.54%, respectively, compared to 32.37% and 32.02% in the control, respectively. HHP treatment decreased the IgE and IgG-binding capacities, indicating a significant decrease in the allergenicity (Pallergenicity, and explained the responses of Hc protein structure to HHP for lowering the allergenicity of squid. PMID:28112159

  9. Suzaku Observations of the Outskirts of A1835: Deviation from Hydrostatic Equilibrium

    Science.gov (United States)

    Ichikawa, Kazuya; Matsushita, Kyoko; Okabe, Nobuhiro; Sato, Kosuke; Zhang, Y.-Y.; Finoguenov, A.; Fujita, Yutaka; Fukazawa, Yasushi; Kawaharada, Madoka; Nakazawa, Kazuhiro; Ohashi, Takaya; Ota, Naomi; Takizawa, Motokazu; Tamura, Takayuki; Umetsu, Keiichi

    2013-04-01

    We present results of four-pointing Suzaku X-ray observations (total ~200 ks) of the intracluster medium (ICM) in the A1835 galaxy cluster (kT ~ 8 keV, z = 0.253) out to the virial radius (r vir ~ 2.9 Mpc) and beyond. Faint X-ray emission from the ICM out to r vir is detected. The temperature gradually decreases with radius from ~8 keV in the inner region to ~2 keV at r vir. The entropy profile is shown to flatten beyond r 500, in disagreement with the r 1.1 dependence predicted from the accretion shock heating model. The thermal pressure profile in the range 0.3r 500 Microwave Anisotropy Probe seven-year data. All these results indicate, rather than the gas-clumping effect, that the bulk of the ICM in the cluster outskirts is far from hydrostatic equilibrium and infalling matter retained some of its kinetic energy. Finally, combining with our recent Suzaku and lensing analysis of A1689, a cluster of similar mass, temperature, and redshift, we show that the cluster temperature distribution in the outskirts is significantly correlated with the galaxy density field in the surrounding large-scale environment at (1-2)r vir.

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

    KAUST Repository

    Yang, Zhi

    2015-12-13

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

  11. Insights into alternative prion protein topologies induced under high hydrostatic pressure

    Energy Technology Data Exchange (ETDEWEB)

    Torrent, Joan [INSERM U128, IFR 122, 1919 Route de Mende, F-34293 Montpellier cedex 5 (France); Alvarez-Martinez, Maria Teresa [INSERM U431, IFR 122, Place Eugene Bataillon, F-34095 Montpellier cedex 5 (France); Heitz, Frederic [CRBM, CNRS-UPR 1086, IFR 122, 1919 Route de Mende, F-34293 Montpellier cedex 5 (France); Liautard, Jean-Pierre [INSERM U431, IFR 122, Place Eugene Bataillon, F-34095 Montpellier cedex 5 (France); Balny, Claude [INSERM U128, IFR 122, 1919 Route de Mende, F-34293 Montpellier cedex 5 (France); Lange, Reinhard [INSERM U128, IFR 122, 1919 Route de Mende, F-34293 Montpellier cedex 5 (France)

    2004-04-14

    The critical step in the pathogenesis of transmissible spongiform encephalopathies (TSEs) appears to be a conformational transition of a normal prion protein (PrP{sup C}) into a misfolded isoform (PrP{sup Sc}). To gain insight into the structural conversion of the prion protein we have exploited the use of high hydrostatic pressure combined with various spectroscopic techniques. In vitro transitions of the recombinant PrP to a scrapie-like form have never resulted in an infectious structure. It is our hypothesis that the acquisition of the disease-causing conformation depends on folding pathways which are difficult to attain. We attempt to favour, via specific reaction conditions at high pressure, alternative routes of misfolding leading to a stable infectious amyloidogenic conformer. Our results have demonstrated the potential of high pressure to reveal various prion structural changes, which are inaccessible by conventional methods. Especially, we have characterized a pressure-induced conformer in which the normal {alpha}-helical structure is changed into a highly aggregated {beta}-sheet conformation showing markedly increased resistance to proteolysis (key markers of potential infectious agents). Our work may have important implications, not only for ultimately proving the protein-only hypothesis and for understanding the basic mechanism of the disease, but also for developing preventative and therapeutic measures.

  12. Effect of treatment temperature on collagen structures of the decellularized carotid artery using high hydrostatic pressure.

    Science.gov (United States)

    Negishi, Jun; Funamoto, Seiichi; Kimura, Tsuyoshi; Nam, Kwangoo; Higami, Tetsuya; Kishida, Akio

    2011-09-01

    Decellularized tissues have attracted a great deal of attention as regenerating transplantation materials. A decellularizing method based on high hydrostatic pressure (HHP) has been developed, and the preparation of many types of decellularized tissues has been investigated, including aorta, cornea, and dermis. The preparation of a small-diameter vascular graft was studied using a carotid artery from the viewpoint of collagen denaturation and leakage. After HHP, the carotid artery was washed at two washing temperatures (37 and 4°C). Histological evaluation, collagen content measurement and circular dichroism (CD) measurement indicated that the washing temperatures clearly affected the collagen structure of the decellularized carotid artery. The amount of collagen decreased in the carotid artery decellularized by HHP washed at 37°C (HHP/37°C). On the other hand, the amount and structure of collagen were preserved in the carotid artery washed at 4°C after HHP (HHP/4°C). In rat carotid artery syngeneic transplantation, the HHP/37°C decellularized carotid artery occluded after 2 weeks, but the HHP/4°C decellularized one did not. These results indicate that collagen denaturation and leakage of the decellularized carotid artery affect the in vivo performance of the carotid artery.

  13. Retrogradation of Maize Starch after High Hydrostatic Pressure Gelation: Effect of Amylose Content and Depressurization Rate.

    Science.gov (United States)

    Yang, Zhi; Swedlund, Peter; Gu, Qinfen; Hemar, Yacine; Chaieb, Sahraoui

    2016-01-01

    High hydrostatic pressure (HHP) has been employed to gelatinize or physically modify starch dispersions. In this study, waxy maize starch, normal maize starch, and two high amylose content starch were processed by a HHP of the order of 600 MPa, at 25°C for 15min. The effect of HHP processing on the crystallization of maize starches with various amylose content during storage at 4°C was investigated. Crystallization kinetics of HHP treated starch gels were investigated using rheology and FTIR. The effect of crystallization on the mechanical properties of starch gel network were evaluated in terms of dynamic complex modulus (G*). The crystallization induced increase of short-range helices structures were investigated using FTIR. The pressure releasing rate does not affect the starch retrogradation behaviour. The rate and extent of retrogradation depends on the amylose content of amylose starch. The least retrogradation was observed in HHP treated waxy maize starch. The rate of retrogradation is higher for HHP treated high amylose maize starch than that of normal maize starch. A linear relationship between the extent of retrogradation (phase distribution) measured by FTIR and G* is proposed.

  14. Effect of high hydrostatic pressure (HHP) on slowly digestible properties of rice starches.

    Science.gov (United States)

    Tian, Yaoqi; Li, Dandan; Zhao, Jianwei; Xu, Xueming; Jin, Zhengyu

    2014-01-01

    The slowly digestible properties of high hydrostatic pressure (HHP)-gelatinized non-waxy and waxy rice starches during the retrogradation were evaluated in this study. The results show that slowly digestible starch (SDS) was observed at a higher percentage in HHP-gelatinized, non-waxy and waxy rice starches than in heat-gelatinized starches, after retrogradation for 7 days. The HHP treatment significantly reduced the enthalpy change of starch retrogradation and retarded the freezable water transformation into unfreezable water during retrogradation. This indicated that the SDS percentage was not positively correlated to the retrogradation degree of starch. Furthermore, X-ray diffraction (XRD) data revealed that the HHP treatment decreased the perfect crystallites of the 7 day-retrograded. Non-waxy and waxy starches from 19.5% to 12.1% and 15.7% to 11.4%, while increased imperfect crystallites from 26.4% to 30.7% and 28.6% to 31.3%, respectively. These findings suggest that the higher SDS percentage can be attributed to the formation of less perfect crystallites and more imperfect crystallites during the HHP and retrogradation treatments.

  15. Hardware-in-loop simulation on hydrostatic thrust bearing worktable pose

    Institute of Scientific and Technical Information of China (English)

    韩桂华; 邵俊鹏; 秦柏; 董玉红

    2008-01-01

    A controllable hydrostatic thrust bearing was presented to improve rigidity. The bearing worktable poses were controlled by coupling oilfilm thickness of four controllable chambers. The chamber flow can be regulated by electro hydraulic servo valve-control variable pump according to the surface roughness, load, cutting force, and thermal effects of worktable. The mathematical models of the controllable chamber flow, servo variable mechanism and controller were built. The pose control model was established, which contained the kinematics positive and negative solution and control strategy of feedforward and hydraulic cylinder position feedback. Hardware-in-loop simulation experiment was carried out on the electro hydraulic servo test bench by means of the non-linear relation of film thickness and hydraulic cylinder displacement. Hardware-in-loop simulation experiment results show that the controllable bearings exhibit high oilfilm rigidity, the rising time is 0.24 s and the maximum overshoot is 2.23%, and can be applied in high precision heavy machine tool.

  16. Microenvironment is involved in cellular response to hydrostatic pressures during chondrogenesis of mesenchymal stem cells.

    Science.gov (United States)

    Ye, Rui; Hao, Jin; Song, Jinlin; Zhao, Zhihe; Fang, Shanbao; Wang, Yating; Li, Juan

    2014-06-01

    Chondrocytes integrate numerous microenvironmental cues to mount physiologically relevant differentiation responses, and the regulation of mechanical signaling in chondrogenic differentiation is now coming into intensive focus. To facilitate tissue-engineered chondrogenesis by mechanical strategy, a thorough understanding about the interactional roles of chemical factors under mechanical stimuli in regulating chondrogenesis is in great need. Therefore, this study attempts to investigate the interaction of rat MSCs with their microenvironment by imposing dynamic and static hydrostatic pressure through modulating gaseous tension above the culture medium. Under dynamic pressure, chemical parameters (pH, pO2, and pCO2) were kept in homeostasis. In contrast, pH was remarkably reduced due to increased pCO2 under static pressure. MSCs under the dynamically pressured microenvironment exhibited a strong accumulation of GAG within and outside the alginate beads, while cells under the statically pressured environment lost newly synthesized GAG into the medium with a speed higher than its production. In addition, the synergic influence on expression of chondrogenic genes was more persistent under dynamic pressure than that under static pressure. This temporal contrast was similar to that of activation of endogenous TGF-β1. Taken altogether, it indicates that a loading strategy which can keep a homeostatic chemical microenvironment is preferred, since it might sustain the stimulatory effects of mechanical stimuli on chondrogenesis via activation of endogenous TGF-β1.

  17. Residual urinary extracellular vesicles in ultracentrifugation supernatants after hydrostatic filtration dialysis enrichment

    Science.gov (United States)

    Musante, Luca; Tataruch-Weinert, Dorota; Kerjaschki, Dontscho; Henry, Michael; Meleady, Paula; Holthofer, Harry

    2017-01-01

    ABSTRACT Urinary extracellular vesicles (UEVs) appear an ideal source of biomarkers for kidney and urogenital diseases. The majority of protocols designed for their isolation are based on differential centrifugation steps. However, little is still known of the type and amount of vesicles left in the supernatant. Here we used an isolation protocol for UEVs which uses hydrostatic filtration dialysis as first pre-enrichment step, followed by differential centrifugation. Transmission electron microscopy (TEM), mass spectrometry (MS), western blot, ELISA assays and tuneable resistive pulse sensing (TRPS) were used to characterise and quantify UEVs in the ultracentrifugation supernatant. TEM showed the presence of a variety of small size vesicles in the supernatant while protein identification by MS matched accurately with the protein list available in Vesiclepedia. Screening and relative quantification for specific vesicle markers showed that the supernatant was preferentially positive for CD9 and TSG101. ELISA tests for quantification of exosome revealed that 14%, was left in the supernatant with a particle diameter of 110 nm and concentration of 1.54 × 1010/ml. Here we show a comprehensive characterisation of exosomes and other small size urinary vesicles which the conventional differential centrifugation protocol may lose.

  18. Results after one year from a Hydrostatic Levelling System installed at Diamond Light Source

    Science.gov (United States)

    Kay, James; Baker, Keith A.; Hoffman, William J.

    2010-06-01

    A Hydrostatic Levelling System (HLS) has been installed at Diamond Light Source. 8 sensors have been positioned along a 60 metre portion of the floor of the Storage Ring and the Experimental Hall, stretching out along a typical beamline route from Insertion Device to sample. 7 of the sensors are installed on the thick, reinforced concrete floor of the Experimental Hall which is supported on piles and the last sensor is mounted on the much thinner concrete floor of the peripheral walkway which has no piles. The foundations and floor were designed to achieve settlements measuring 1 micron per 10 metres per hour and 10 microns per 10 metres per day. A larger range was specified of 250 microns per 10 metres per year on the Experimental Hall floor and 100 microns per 10 metres per year in the Storage Ring to account for longer term settlement effects and seasonal variation and the HLS has been installed to try and measure these very small movements. Results after one year of operation are presented.

  19. ScVO4 under non-hydrostatic compression: a new metastable polymorph

    Science.gov (United States)

    Garg, Alka B.; Errandonea, D.; Rodríguez-Hernández, P.; Muñoz, A.

    2017-02-01

    The high-pressure (HP) behaviour of scandium vanadate (ScVO4) is investigated under non-hydrostatic compression. The compound is studied by means of synchrotron-based powder x-ray diffraction (XRD) and optical-absorption techniques. The occurrence of a non-reversible phase transition is detected. The transition is from the zircon structure to the fergusonite-type structure and takes place around 6 GPa with nearly 10% volume discontinuity. XRD measurements on the pressure cycled sample confirm for the first time that the fergusonite-type ScVO4 can be recovered as the metastable phase at ambient conditions. Raman spectroscopic measurements verify the metastable phase to be of a fergusonite-type phase. Theoretical calculations also corroborate the experimental findings. The fergusonite phase is found to be stiffer than the ambient-pressure zircon phase, as indicated by the observed experimental and theoretical bulk moduli. The optical properties and lattice-dynamics calculation of the fergusonite ScVO4 are discussed. At ambient pressure the band gap of the zircon (fergusonite)-type ScVO4 is 2.75 eV (2.3 eV). This fact suggests that the novel metastable polymorph of ScVO4 can have applications in green technologies; for instance, it can be used as photocatalytic material for hydrogen production by water splitting.

  20. Predictive Model for Inactivation of Feline Calicivirus, a Norovirus Surrogate, by Heat and High Hydrostatic Pressure▿

    Science.gov (United States)

    Buckow, Roman; Isbarn, Sonja; Knorr, Dietrich; Heinz, Volker; Lehmacher, Anselm

    2008-01-01

    Noroviruses, which are members of the Caliciviridae family, represent the leading cause of nonbacterial gastroenteritis in developed countries; such norovirus infections result in high economic costs for health protection. Person-to-person contact, contaminated water, and foods, especially raw shellfish, vegetables, and fruits, can transmit noroviruses. We inactivated feline calicivirus, a surrogate for the nonculturable norovirus, in cell culture medium and mineral water by heat and high hydrostatic pressure. Incubation at ambient pressure and 75°C for 2 min as well as treatment at 450 MPa and 15°C for 1 min inactivated more than 7 log10 PFU of calicivirus per ml in cell culture medium or mineral water. The heat and pressure time-inactivation curves obtained with the calicivirus showed tailing in the logarithmic scale. Modeling by nth-order kinetics of the virus inactivation was successful in predicting the inactivation of the infective virus particles. The developed model enables the prediction of the calicivirus reduction in response to pressures up to 500 MPa, temperatures ranging from 5 to 75°C, and various treatment times. We suggest high pressure for processing of foods to reduce the health threat posed by noroviruses. PMID:18156330

  1. A deep non-hydrostatic compressible atmospheric model on a Yin-Yang grid

    Science.gov (United States)

    Allen, T.; Zerroukat, M.

    2016-08-01

    The singularity in the traditional spherical polar coordinate system at the poles is a major factor in the lack of scalability of atmospheric models on massively parallel machines. Overset grids such as the Yin-Yang grid introduced by Kageyama and Sato [1] offer a potential solution to this problem. In this paper a three-dimensional, compressible, non-hydrostatic atmospheric model is developed and tested on the Yin-Yang grid building on ideas previously developed by the authors on the solution of Elliptic boundary value problems and conservation on overset grids. Using several tests from the literature, it is shown that this model is highly stable (even with little off-centering), accurate, and highly efficient in terms of computational cost. The model also incorporates highly efficient and accurate approaches to achieve positivity, monotonicity and conservative transport, which are paramount requirements for any atmospheric model. The parallel scalability of this model, using in excess of 212 million unknowns and more than 6000 processors, is also discussed and shown to compare favourably with a highly optimised latitude-longitude model in terms of scalability and actual run times.

  2. HIGH HYDROSTATIC PRESSURE EXTRACTION OF ANTIOXIDANTS FROM MORINDA CITRIFOLIA FRUIT – PROCESS PARAMETERS OPTIMIZATION

    Directory of Open Access Journals (Sweden)

    PRAVEEN KUMAR

    2006-06-01

    Full Text Available A modified version of high hydrostatic pressure extraction has been performed for extraction of antioxidants from M. citrifolia fruit at 5, 15, 25 bar and temperature 30° to 70°C for time duration 1, 2, 4 and 6 hours. The antioxidant activity of the extracts was determined by di-phenylpicrylhydrazyl radical scavenging method. The process parameters were optimized for antioxidant activity by central composite design method of response surface methodology using the statistical package, design expert. The results are expressed as 3D surface graphs. The optimum antioxidant activity was achieved at 58°C and 5 hours for 25bar. The optimal result achieved was within the region of response surface methodology. The statistical results were compared with the experimental result at 25bar, 2hour and 30° to 70°C and were found to be in proximate. The antioxidant activities of the extracts were found to increase with increase in pressure. It was also found that the response surface methodology works effectively for shorter range of parameters considered.

  3. Retrogradation of Maize Starch after High Hydrostatic Pressure Gelation: Effect of Amylose Content and Depressurization Rate.

    Directory of Open Access Journals (Sweden)

    Zhi Yang

    Full Text Available High hydrostatic pressure (HHP has been employed to gelatinize or physically modify starch dispersions. In this study, waxy maize starch, normal maize starch, and two high amylose content starch were processed by a HHP of the order of 600 MPa, at 25°C for 15min. The effect of HHP processing on the crystallization of maize starches with various amylose content during storage at 4°C was investigated. Crystallization kinetics of HHP treated starch gels were investigated using rheology and FTIR. The effect of crystallization on the mechanical properties of starch gel network were evaluated in terms of dynamic complex modulus (G*. The crystallization induced increase of short-range helices structures were investigated using FTIR. The pressure releasing rate does not affect the starch retrogradation behaviour. The rate and extent of retrogradation depends on the amylose content of amylose starch. The least retrogradation was observed in HHP treated waxy maize starch. The rate of retrogradation is higher for HHP treated high amylose maize starch than that of normal maize starch. A linear relationship between the extent of retrogradation (phase distribution measured by FTIR and G* is proposed.

  4. High hydrostatic pressure processing: a method having high success potential in pollen protein extraction

    Science.gov (United States)

    Murat Altuner, Ergin; Çeter, Talip; Alpas, Hami

    2012-06-01

    Even a single peptide that is present in the pollen wall and cytoplasm could cause pollen allergy. To produce skin-prick test kits, the first step is the extraction of these molecules. In this study, Cedrus atlantica pollens were subjected to 220 and 330 MPa for 10 and 30 min in order to extract these molecules. After high hydrostatic pressure processing (HHPP), the total amounts of proteins (TAPs) are measured and compared with the results of the conventional extraction method (CEM). As a result, the TAPs extracted by HHPP is 18.0210 μ g/mL at 220 MPa for 10 min, 22.5770 μ g/mL at 220 MPa for 30 min, 23.3810 μ g/mL at 330 MPa for 10 min and 25.9270 μ g/mL at 330 MPa for 30 min, while this is 1.9460 μ g/mL in 24 h by the CEM. In addition to these results, visual pollen deformation and eruption, pollen wall and surface damage have also been observed.

  5. Sustainable production of pectin from lime peel by high hydrostatic pressure treatment.

    Science.gov (United States)

    Naghshineh, Mahsa; Olsen, Karsten; Georgiou, Constantinos A

    2013-01-15

    The application of high hydrostatic pressure technology for enzymatic extraction of pectin was evaluated. Cellulase and xylanase under five different combinations (cellulase/xylanase: 50/0, 50/25, 50/50, 25/50, and 0/50 U/g lime peel) at ambient pressure, 100 and 200 MPa were used to extract pectin from dried lime peel. Extraction yield, galacturonic acid (GalA) content, average molecular weight (M(w,ave)), intrinsic viscosity [η](w), and degree of esterification (DE) were compared to those parameters obtained for pectins extracted using acid and aqueous processes. Pressure level, type and concentration of enzyme significantly (ppectin. Enzyme and high pressure extraction resulted in yields which were significantly (pextraction. Although pressure-induced enzymatic treatment improves pectin yield, it does not have any significant effect on M(w,ave) and [η](w) of pectin extracts indicating the potential of high pressure treatment for enzymatic pectin production as a novel and sustainable process.

  6. Effects of high hydrostatic pressure on secondary structure and emulsifying behavior of sweet potato protein

    Science.gov (United States)

    Mehmood Khan, Nasir; Mu, Tai-Hua; Sun, Hong-Nan; Zhang, Miao; Chen, Jing-Wang

    2015-04-01

    In this study, secondary structures of sweet potato protein (SPP) after high hydrostatic pressure (HHP) treatment (200-600 MPa) were evaluated and emulsifying properties of emulsions with HHP-treated SPP solutions in different pH values (3, 6, and 9) were investigated. Circular dichroism analysis confirmed the modification of the SPP secondary structure. Surface hydrophobicity increased at pH 3 and decreased at 6 and 9. Emulsifying activity index at pH 6 increased with an increase in pressure, whereas emulsifying stability index increased at pH 6 and 9. Oil droplet sizes decreased, while volume frequency distribution of the smaller droplets increased at pH 3 and 6 with the HHP treatment. Emulsion viscosity increased at pH 6 and 9 and pseudo-plastic flow behaviors were not altered for all emulsions produced with HHP-treated SPP. These results suggested that HHP could modify the SPP structure for better emulsifying properties, which could increase the use of SPP emulsion in the food industry.

  7. Phase transformation kinetics and microstructure of NiTi shape memory alloy: effect of hydrostatic pressure

    Indian Academy of Sciences (India)

    CENGIZ TATAR; ZÜLKÜF YILDIRIM

    2017-08-01

    The effect of hydrostatic pressure on the behaviour of reverse and forward transformation temperatures andphysical properties of NiTi shape memory alloy has been investigated. The transformation temperatures and physical properties of the alloy change with applied pressure. It has been clearly seen from differential scanning calorimetry that with theincrease of applied pressure, while $A_{\\rm s}$, $A_{\\rm f}$ and $M_{\\rm f}$ transformation temperatures decrease, Ms value increases. Moreover, it is obvious that with the increase of applied pressure, Gibbs free energy increases by 5.2883 J, while elastic energy increases by 1.4687 J. In addition, entropy of the alloys decreases by 0.2335 J (g $^{\\circ}$C)$^{−1}$ with applied pressure. Additionally, it is evident from the scanning electron microscopy images of the samples that there is an obvious difference in the grain sizes of the unpressured sample and the samples on which pressure is applied, the sizes being 10–100 and 30–150 $\\mu$m, respectively.

  8. Hydrostatic equilibrium of a porous intracluster medium: implications for mass fraction and X-ray luminosity

    CERN Document Server

    Nusser, Adi

    2007-01-01

    The presence of dilute hot cavities in the intracluster medium (ICM) at the cores of clusters of galaxies changes the relation between gas temperature and its X-ray emission properties. Using the hydrostatic equations of a porous medium we solve for the ICM density for a given temperature as a function of the filling factor of dilute bubbles. We find that at a given temperature, the core X-ray luminosity increases with the filling factor. If the frequency of AGNs in clusters were higher in the past, then the filling factor is correspondingly affected, with implications for the cluster scaling relations. This is especially important for the core properties, including the temperature-luminosity ($L_X-T$) relation and estimates of the core gas mass. The results imply an epoch-dependent sensitivity of the $L_X-T$ relation in the core to the porosity of the ICM. Detection of such an effect would give new insights into AGN feedback.

  9. A multi-purpose modular system for high-resolution microscopy at high hydrostatic pressure

    CERN Document Server

    Vass, Hugh; Herzig, Eva M; Ward, F Bruce; Clegg, Paul S; Allen, Rosalind J

    2009-01-01

    We have developed a modular system for high-resolution microscopy at high hydrostatic pressure. The system consists of a pressurised cell of volume ~100 microlitres, a temperature controlled holder, a ram and a piston. We have made each of these components in several versions which can be interchanged to allow a wide range of applications. Here, we report two pressure cells with pressure ranges 0.1-700MPa and 0.1-100MPa, which can be combined with hollow or solid rams and pistons. Our system is designed to work with fluorescent samples (using a confocal or epifluorescence microscope), but also allows for transmitted light microscopy via the hollow ram and piston. The system allows precise control of pressure and temperature [-20-70C], as well as rapid pressure quenching. We demonstrate its performance and versatility with two applications: time-resolved imaging of colloidal phase transitions caused by pressure changes between 0.1MPa and 101MPa, and imaging the growth of Escherichia coli bacteria at 50MPa. We ...

  10. Conduction mechanisms in some graphite-polymer composites: Effects of temperature and hydrostatic pressure

    Science.gov (United States)

    Celzard, A.; McRae, E.; Marêché, J. F.; Furdin, G.; Sundqvist, B.

    1998-02-01

    This article is devoted to the conduction mechanisms involved in some highly electrically anisotropic resin-graphite particle composites. These materials are known to show a percolation phenomenon as the filler content is varied; they are epoxy or polyurethane based, the conducting particles are oriented single-crystal platelets, and samples are in the form of thick films. Because of their strong anisotropy, two types of measurements were made, i.e., parallel to and perpendicular to the plane of the films. Study of the resistivity variations of samples containing various concentrations in conducting particles was carried out first as a function of temperature from 4.2 to 300 K at ambient pressure, and second as a function of hydrostatic pressure up to 1.2 GPa, at room temperature. As the temperature is varied, the changes in resistivity of all the samples studied (i.e., above percolation threshold) are weak; analysis leads to the conclusion that thermally activated tunneling plays a dominant role above but close to the percolation threshold φc. As a function of pressure, more samples were studied: when the filler content is above φc, resistivity changes are quantitatively in agreement with what is expected from both percolation theory and tunneling; below threshold, the observed behavior is partially attributable to an ionic conduction mechanism throughout the polymer.

  11. Synthetic photometry for carbon rich giants, I. Hydrostatic dust-free models

    CERN Document Server

    Aringer, B; Nowotny, W; Marigo, P; Lederer, M T

    2009-01-01

    We study the spectroscopic and photometric properties of carbon stars. In the first paper of this series we focus on objects that can be described by hydrostatic models neglecting dynamical phenomena like pulsation and mass loss. As a consequence, the reddening due to circumstellar dust is not included. Our results are collected in a database, which can be used in conjunction with stellar evolution and population synthesis calculations involving the AGB. We have computed a grid of 746 spherically symmetric COMARCS atmospheres covering effective temperatures between 2400 and 4000K, surface gravities from log(g) = 0.0 to -1.0, metallicities ranging from the solar value down to one tenth of it and C/O ratios in the interval between 1.05 and 5.0. Subsequently, we used these models to create synthetic low resolution spectra and photometric data for a large number of filter systems. The tables including the results are electronically available. We have selected some of the most commonly used colours in order to dis...

  12. The effect of neutron irradiation on oxygen aggregation processes in Si material treated under hydrostatic pressure

    Energy Technology Data Exchange (ETDEWEB)

    Londos, Charalampos A.; Andrianakis, Andreas [Solid State Section, Physics Department, University of Athens, Panepistimiopolis, Zografos, 157 84 Athens (Greece); Misiuk, Andrzej [Institute of Electron Technology, Al. Lotnikow 46, 02-668 Warsaw (Poland)

    2011-03-15

    Silicon is the dominant material in electronic industry. Its use for various applications requires processing stages, important among them those involving thermal treatments. Such treatments in Si trigger the mechanisms of oxygen aggregation resulting in the formation of oxygen precipitates which have important influence on the quality of the material. In the present work, we have investigated the effect of thermal treatments, with or without the application of high hydrostatic pressure, on the development of oxygen precipitates. We have particularly studied the effect of neutron irradiation on the formation of the various oxygen agglomerates in the course of the above treatments. To this end, Si samples initially irradiated by neutrons were subjected to high temperature or/and high temperature-high pressure treatments at 1000 and 1130 C. Afterwards, infrared (IR) measurements were undertaken to study various precipitate morphologies, in particular those giving rise to an IR band around 1080 cm{sup -1} related to octahedral-shaped precipitates and an IR band at 1225 cm{sup -1} attributed to platelet-shaped precipitates. The obtained results were found to be consistent with reports cited in the literature. It was confirmed that the application of pressure during treatments as well as the irradiation with neutrons before these treatments enhance substantially the oxygen aggregation process. Comparisons of the results between treatments at 1000 and 1130 C are presented and discussed. (Copyright copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  13. The Rapid Inactivation of Porcine Skin by Applying High Hydrostatic Pressure without Damaging the Extracellular Matrix

    Directory of Open Access Journals (Sweden)

    Naoki Morimoto

    2015-01-01

    Full Text Available We previously reported that high hydrostatic pressure (HHP of 200 MPa for 10 minutes could induce cell killing. In this study, we explored whether HHP at 200 MPa or HHP at lower pressure, in combination with hyposmotic distilled water (DW, could inactivate the skin, as well as cultured cells. We investigated the inactivation of porcine skin samples 4 mm in diameter. They were immersed in either a normal saline solution (NSS or DW, and then were pressurized at 100 and 200 MPa for 5, 10, 30, or 60 min. Next, we explored the inactivation of specimens punched out from the pressurized skin 10 × 2 cm in size. The viability was evaluated using a WST-8 assay and an outgrowth culture. The histology of specimens was analyzed histologically. The mitochondrial activity was inactivated after the pressurization at 200 MPa in both experiments, and no outgrowth was observed after the pressurization at 200 MPa. The arrangement and proportion of the dermal collagen fibers or the elastin fibers were not adversely affected after the pressurization at 200 MPa for up to 60 minutes. This study showed that a HHP at 200 MPa for 10 min could inactivate the skin without damaging the dermal matrix.

  14. Optical Probes of MEH-PPV films at High Hydrostatic Pressure

    Science.gov (United States)

    Olejnik, E.; Singh, S.; Pandit, B.; Morandi, V.; Holt, J.; Sheng, C.-X.; Vardeny, Z. V.

    2010-03-01

    We investigate the primary and long-lived photoexcitations in π-conjugated polymer films with increased interchain coupling by studying the photophysics of substituted PPV derivative thin films, namely 2-methoxy-5-(2'-ethylhexyloxy) [MEH-PPV] at high hydrostatic pressure, P up to 120 kbar in a diamond anvil cell, using both ultrafast transient mid- and near-IR spectroscopies with 0.1 ps resolution, and cw optical techniques (photo induced absorption (PA) and photoluminescence (PL) in a broad spectral range from 0.2 to 2.2 eV). With increasing P the cw PL band weakens, broadens, and red-shifts by ˜ 2 meV/kbar; whereas the triplet PA red shifts to a lesser extent. The ultrafast PA band of the singlet exciton at ˜ 0.95 eV at ambient splits, blue shifts and acquires a much longer decay component. A second, weak PA band at ˜ 0.33 eV at ambient, dramatically blue-shifts (˜ 3 meV/kbar) and substantially intensifies with P. These pressure-induced effects are discussed considering the interplay of two phases in the MEH-PPV film: a disordered phase with large PL efficiency, and PA that does not change much with P; and a less emissive ordered phase that increases with P, where the interchain coupling substantially increases with P.

  15. Microstructure and Texture Evolutions of Biomedical Ti-13Nb-13Zr Alloy Processed by Hydrostatic Extrusion

    Science.gov (United States)

    Ozaltin, K.; Panigrahi, A.; Chrominski, W.; Bulutsuz, A. G.; Kulczyk, M.; Zehetbauer, M. J.; Lewandowska, M.

    2017-08-01

    A biomedical β-type Ti-13Nb-13Zr (TNZ) (wt pct) ternary alloy was subjected to severe plastic deformation by means of hydrostatic extrusion (HE) at room temperature without intermediate annealing. Its effect on microstructure, mechanical properties, phase transformations, and texture was investigated by light and electron microscopy, mechanical tests (Vickers microhardness and tensile tests), and XRD analysis. Microstructural investigations by light microscope and transmission electron microscope showed that, after HE, significant grain refinement took place, also reaching high dislocation densities. Increases in strength up to 50 pct occurred, although the elongation to fracture left after HE was almost 9 pct. Furthermore, Young's modulus of HE-processed samples showed slightly lower values than the initial state due to texture. Such mechanical properties combined with lower Young's modulus are favorable for medical applications. Phase transformation analyses demonstrated that both initial and extruded samples consist of α' and β phases but that the phase fraction of α' was slightly higher after two stages of HE.

  16. Radiation thermo-chemical models of protoplanetary disks I. Hydrostatic disk structure and inner rim

    CERN Document Server

    Woitke, Peter; Thi, Wing-Fai

    2009-01-01

    This paper introduces a new disk code, called ProDiMo, to calculate the thermo-chemical structure of protoplanetary disks and to interpret gas emission lines from UV to sub-mm. We combine frequency-dependent 2D dust continuum radiative transfer, kinetic gas-phase and UV photo-chemistry, ice formation, and detailed non-LTE heating & cooling balance with the consistent calculation of the hydrostatic disk structure. We include FeII and CO ro-vibrational line heating/cooling relevant for the high-density gas close to the star, and apply a modified escape probability treatment. The models are characterized by a high degree of consistency between the various physical, chemical and radiative processes, where the mutual feedbacks are solved iteratively. In application to a T Tauri disk extending from 0.5AU to 500AU, the models are featured by a puffed-up inner rim and show that the dense, shielded and cold midplane (z/r<0.1, Tg~Td) is surrounded by a layer of hot (5000K) and thin (10^7 to 10^8 cm^-3) atomic ga...

  17. X-ray irradiated protoplanetary disk atmospheres II: Predictions from models in hydrostatic equilibrium

    CERN Document Server

    Ercolano, Barbara; Drake, Jeremy J

    2009-01-01

    We present new models for the X-ray photoevaporation of circumstellar discs which suggest that the resulting mass loss (occurring mainly over the radial range 10-40 AU) may be the dominant dispersal mechanism for gas around low mass pre-main sequence stars, contrary to the conclusions of previous workers. Our models combine use of the MOCASSIN Monte Carlo radiative transfer code and a self-consistent solution of the hydrostatic structure of the irradiated disc. We estimate the resulting photoevaporation rates assuming sonic outflow at the surface where the gas temperature equals the local escape temperature and derive mass loss rates of ~10^{-9} M_sun/yr, typically a factor 2-10 times lower than the corresponding rates in our previous work (Ercolano et al., 2008) where we did not adjust the density structure of the irradiated disc. The somewhat lower rates, and the fact that mass loss is concentrated towards slightly smaller radii, result from the puffing up of the heated disc at a few AU which partially scre...

  18. Dynamics of phenotypic reversibility of bacterial cells with oscillating hydrostatic pressure

    Science.gov (United States)

    Nepal, Sudip; Kumar, Pradeep

    Bacterial cells encounter and respond to physiochemical fluctuations. The response depends on the extent and type of the stresses applied. The response of bacterial cells to the fluctuating stress is relatively unknown. Here, we have studied the response of wild type Escherichia coli (E. coli) under fluctuating hydrostatic pressures ranging from 1 atm to 500 atm. High pressure acts as a stress to E. coli since these bacteria are adapted to grow optimally at atmospheric pressure. Cell division of E. coli is inhibited at high pressures resulting in increase in the length of the cells. Cell-length is reversible in nature and bacterial cells revert back to normal size on a time scale that is proportional to the strength and time of continuous pressure applied upon relaxing the high pressure condition. We have studied the dynamics of cellular reversibility of E. coli under the conditions in which continuous pressure is applied and subsequently relaxed over different time scales. We have quantified the dynamics of cellular reversibility with different relaxation times. Furthermore, we propose a model to describe the reversibility of the bacterial cell with the relaxation time. Our theoretical model fits well to the experimental data. We further

  19. Balón hidrostático de gran diámetro en coledocolitiasis Large hydrostatic ballon for choledocolithiasis

    Directory of Open Access Journals (Sweden)

    J. Espinel

    2007-01-01

    Full Text Available Objetivo: valorar la eficacia y seguridad de la dilatación hidrostática con balones de gran diámetro en el tratamiento de la coledocolitiasis en pacientes con factores que dificultan o hacen peligrosa la extracción, por las características de los cálculos o de la anatomía peripapilar. Diseño: prospectivo. Pacientes: estudio que incluye 22 pacientes a los que se realizó dilatación hidrostática de la papila con balones de gran diámetro entre junio de 2005 y abril de 2006 por presentar cálculos de gran tamaño, múltiples, colédoco distal afilado, papila peri-/intradiverticular, esfinterotomía previa o Billroth-II. Se emplearon dilatadores CRE de esófago, píloro y colon (Boston Scientific Corporation de diámetros entre 12 y 20 mm. Resultados: se consiguió la extracción de los cálculos en una sesión en todos los pacientes (100%. La mayor parte de las exploraciones (73% no requirieron tiempos prolongados para la extracción. No hubo complicaciones. Se detectó hiperamilasemia en el 18% de los pacientes. Conclusiones: la dilatación hidrostática de la papila con balones de gran diámetro es una técnica sencilla, eficaz y segura en la extracción de cálculos difíciles de la vía biliar, sin incrementar el tiempo de la exploración, ni las complicaciones, reduciendo la necesidad de litotricia. Son necesarios estudios adicionales para definir la utilidad de esta técnica.Aim: to assess the efficacy and safety of hydrostatic dilatation with large balloons for the treatment of choledocolithiasis in patients with difficult or risky extraction due to stone characteristics or peripapillary anatomy. Design: prospective. Patients: this study included 22 patients in whom a hydrostatic dilatation of the papilla with large balloons was performed between June 2005 and April 2006. Patients had multiple large stones, tapered distal common bile duct, peri-/intradiverticular papilla, previous sphincterotomy, or Billroth-II surgery. Esophageal

  20. A SEMI-IMPLICIT 3-D NUMERICAL MODEL USING SIGAM-COOR- DINATE FOR NON-HYDROSTATIC PRESSURE FREE-SURFACE FLOWS

    Institute of Scientific and Technical Information of China (English)

    HU De-chao; FAN Bei-lin; WANG Guang-qian; ZHANG Hong-wu

    2011-01-01

    A 3-D numerical formulation is proposed on the horizontal Cartesian, vertical sigma-coordinate grid for modeling non-hydrostatic pressure free-surface flows.The pressure decomposition technique and θ semi-implicit method are used, with the solution procedure being split into two steps.First, with the implicit parts of non-hydrostatic pressures excluded, the provisional velocity field and free surface are obtained by solving a 2-D Poisson equation.Second, the theory of the differential operator is employed to derive the 3-D Poisson equation for non-hydrostatic pressures, which is solved to obtain the non-hydrostatic pressures and to update the provisional velocity field.When the non-orthogonal sigma-coordinate transformation is introduced, additional terms come into being, resulting in a 15-diagonal, diagonally dominant but unsymmetric linear system in the 3-D Poisson equation for non-hydrostatic pressures.The Biconjugate Gradient Stabilized (BiCGstab) method is used to solve the resulting 3-D unsymmetric linear system instead of the conjugate gradient method, which can only be used for symmetric, positive-definite linear systems.Three test cases are used for validations.The successful simulations of the small-amplitude wave, a supercritical flow over a ramp and a turbulent flow in the open channel indicate that the new model can simulate well non-hydrostatic flows, supercritical flows and turbulent flows.

  1. Drag generation by interfacial waves at an inversion/thermocline in non-hydrostatic flow past an axisymmetric obstacle

    Science.gov (United States)

    Teixeira, Miguel A. C.; Paci, Alexandre; Belleudy, Anne

    2017-04-01

    The drag associated with 3D trapped lee waves generated at a density interface by an axisymmetric obstacle is evaluated using a linear non-hydrostatic model. These waves propagate at temperature inversions capping the boundary layer in the atmosphere, or at the oceanic thermocline, generated by, for example, drifting ice keels. They are responsible for near-surface drag that may be misrepresented as turbulent form drag in numerical models. This drag receives contributions from a continuous wavenumber range forced by the obstacle, in contrast with 2D flow (where only discrete wave modes exist), as the waves are able to vary their angle of incidence with respect to the incoming flow to satisfy their dispersion relationship. Hence (and again in contrast with 2D linear flow), the drag is non-zero both for subcritical and supercritical flow, and attains a maximum for a value of the Froude number slightly smaller than 1. This drag maximum has lower magnitude than in the hydrostatic limit, due to the effect of wave dispersion. The drag calculated from the model is in good agreement with that obtained from experiments carried out in a laboratory water flume that use axisymmetric obstacles of different heights, especially for the lowest obstacle (as would be expected). The best agreement is achieved when the effects of both a rigid lid bounding the fluid layer further away from the obstacle, and friction (represented as a Rayleigh damping), are taken into account. The model is not as quantitatively accurate when the highest obstacle used in the experiments is considered, as this corresponds to stronger flow nonlinearity. But, even in that case, the model has a qualitatively correct behaviour, which is much more accurate than the 3D hydrostatic or 2D non-hydrostatic limits. This suggests that 3D and non-hydrostatic effects to a large extent determine the drag behaviour observed in the experiments. The wave signatures associated with this behaviour are dominated by transverse

  2. 超高压辅助酶法制备低酯果胶%Preparation of low-methoxyl pectin by high hydrostatic pressure-assisted with enzyme methods

    Institute of Scientific and Technical Information of China (English)

    赵文婷; 郭兴峰; 高林; 胡小松; 吴继红

    2015-01-01

    Low methoxyl pectin is widely applied as thickener, stabilizer and emulsifier in low calorie or dietetic foods. The main methods reported for the preparation of low methoxyl pectin from high methoxyl pectin have used four types of agents:acids, ammonia in alcohol or concentrated aqueous ammonia, alkali and pectin methyl esterase. The main disadvantage of the first two methods is the slowness of reaction. Alkaline de-esterification is rapid but the removal of methyl ester groups is accompanied by depolymerization of pectin chains. Enzymatic de-esterification represents an attractive alternative to chemical de-esterification, for it is without pollution, but it is time-consuming. Therefore, there is a need to explore new methods to produce pectin with high quality and efficiency. In this study, a novel method of high hydrostatic pressure combined with enzymatic treatment (pectin methyl esterase) was applied in pectin de-esterification. In order to find out the effect of enzymatic treatment assisted with high hydrostatic pressure on the properties of pectin and promote the industrial development of this technology, the physicochemical properties, molecular weight distribution and rheological characteristics of pectins de-esterified by this treatment were investigated and compared with conventional alkaline method. During the de-esterification process of enzymatic treatment assisted with high hydrostatic pressure of 200 and 300 MPa, the degree of de-esterification was reduced from 61.83%to 34.09%and 32.62%in 10 min, respectively. With further de-esterification, the reaction slowed down, while the de-esterification degree of pectin by alkaline method was reduced to 35.54%and decreased continuously when the period was prolonged to 20 min. Based on this experiment, two pairs of pectins with similar degree of de-esterification were prepared by the enzymatic treatment assisted with high hydrostatic pressure and conventional alkaline method, i.e. HHP-1 (200 MPa, 10 min; 34

  3. Radiation thermo-chemical models of protoplanetary disks. I. Hydrostatic disk structure and inner rim

    Science.gov (United States)

    Woitke, P.; Kamp, I.; Thi, W.-F.

    2009-07-01

    Context: Emission lines from protoplanetary disks originate mainly in the irradiated surface layers, where the gas is generally warmer than the dust. Therefore, interpreting emission lines requires detailed thermo-chemical models, which are essential to converting line observations into understanding disk physics. Aims: We aim at hydrostatic disk models that are valid from 0.1 AU to 1000 AU to interpret gas emission lines from UV to sub-mm. In particular, our interest lies in interpreting far IR gas emission lines, such as will be observed by the Herschel observatory, related to the Gasps open time key program. This paper introduces a new disk code called ProDiMo. Methods: We combine frequency-dependent 2D dust continuum radiative transfer, kinetic gas-phase and UV photo-chemistry, ice formation, and detailed non-LTE heating & cooling with the consistent calculation of the hydrostatic disk structure. We include Fe ii and CO ro-vibrational line heating/cooling relevant to the high-density gas close to the star, and apply a modified escape-probability treatment. The models are characterised by a high degree of consistency between the various physical, chemical, and radiative processes, where the mutual feedbacks are solved iteratively. Results: In application to a T Tauri disk extending from 0.5 AU to 500 AU, the models show that the dense, shielded and cold midplane (z/r ⪉ 0.1, T g≈ T d) is surrounded by a layer of hot (T g≈ 5000 K) and thin (n ≈10 7 to 10 8 cm-3) atomic gas that extends radially to about 10 AU and vertically up to z/r≈0.5. This layer is predominantly heated by the stellar UV (e.g. PAH-heating) and cools via Fe ii semi-forbidden and Oi 630 nm optical line emission. The dust grains in this “halo” scatter the starlight back onto the disk, which affects the photochemistry. The more distant regions are characterised by a cooler flaring structure. Beyond r ⪆ 100 AU, T g decouples from T d even in the midplane and reaches values of about T

  4. High hydrostatic pressure treatment for the inactivation of Staphylococcus aureus in human blood plasma.

    Science.gov (United States)

    Rivalain, Nolwennig; Roquain, Jean; Boiron, Jean-Michel; Maurel, Jean-Paul; Largeteau, Alain; Ivanovic, Zoran; Demazeau, Gérard

    2012-02-15

    For the past 30years, pressure inactivation of microorganisms has been developed in biosciences, in particular for foods and more recently for biological products, including pharmaceutical ones. In many past studies, the effect of high hydrostatic pressure (HHP) processes on pathogens focused mainly on the effect of an increase of the pressure value. To assure the safety of pharmaceutical products containing fragile therapeutic components, development of new decontamination processes at the lowest pressure value is needed to maintain their therapeutic properties. The aim of this study was therefore to evaluate the impact of the process parameters characterizing high-pressure treatments [such as the pressurization rate (PR) and the application mode (AM)] on the inactivation of pathogens, in particular to determine how these parameters values could help decrease the pressure value necessary to reach the same inactivation level. The effect of these physical parameters was evaluated on the inactivation of Staphylococcus aureus ATCC 6538 which is an opportunistic pathogen of important relevance in the medical, pharmaceutical and food domains. Human blood plasma was chosen as the suspension medium because of its physiological importance in the transfusion field. It was shown that the optimization of all the selected parameters could lead to a high inactivation level (≈5log(10) decrease of the initial bacterial load) at a pressure level as low as 200MPa, underlining some synergistic effects among these parameters. Complete inactivation of the initial bacterial population was achieved for the following conditions: PR=50MPas(-1), AM=5×2min, T≈-5°C and P=300MPa.

  5. Turning performance in squid and cuttlefish: unique dual-mode, muscular hydrostatic systems.

    Science.gov (United States)

    Jastrebsky, Rachel A; Bartol, Ian K; Krueger, Paul S

    2016-05-01

    Although steady swimming has received considerable attention in prior studies, unsteady swimming movements represent a larger portion of many aquatic animals' locomotive repertoire and have not been examined extensively. Squids and cuttlefishes are cephalopods with unique muscular hydrostat-driven, dual-mode propulsive systems involving paired fins and a pulsed jet. These animals exhibit a wide range of swimming behavior, but turning performance has not been examined quantitatively. Brief squid, Lolliguncula brevis, and dwarf cuttlefish, Sepia bandensis, were filmed during turns using high-speed cameras. Kinematic features were tracked, including the length-specific radius of the turn (R/L), a measure of maneuverability, and angular velocity (ω), a measure of agility. Both L. brevis and S. bandensis demonstrated high maneuverability, with (R/L)min values of 3.4×10(-3)±5.9×10(-4) and 1.2×10(-3)±4.7×10(-4) (mean±s.e.m.), respectively, which are the lowest measures of R/L reported for any aquatic taxa. Lolliguncula brevis exhibited higher agility than S. bandensis (ωa,max=725.8 versus 485.0 deg s(-1)), and both cephalopods have intermediate agility when compared with flexible-bodied and rigid-bodied nekton of similar size, reflecting their hybrid body architecture. In L. brevis, jet flows were the principal driver of angular velocity. Asymmetric fin motions played a reduced role, and arm wrapping increased turning performance to varying degrees depending on the species. This study indicates that coordination between the jet and fins is important for turning performance, with L. brevis achieving faster turns than S. bandensis and S. bandensis achieving tighter, more controlled turns than L. brevis.

  6. Cuttlefish skin papilla morphology suggests a muscular hydrostatic function for rapid changeability.

    Science.gov (United States)

    Allen, Justine J; Bell, George R R; Kuzirian, Alan M; Hanlon, Roger T

    2013-06-01

    Coleoid cephalopods adaptively change their body patterns (color, contrast, locomotion, posture, and texture) for camouflage and signaling. Benthic octopuses and cuttlefish possess the capability, unique in the animal kingdom, to dramatically and quickly change their skin from smooth and flat to rugose and three-dimensional. The organs responsible for this physical change are the skin papillae, whose biomechanics have not been investigated. In this study, small dorsal papillae from cuttlefish (Sepia officinalis) were preserved in their retracted or extended state, and examined with a variety of histological techniques including brightfield, confocal, and scanning electron microscopy. Analyses revealed that papillae are composed of an extensive network of dermal erector muscles, some of which are arranged in concentric rings while others extend across each papilla's diameter. Like cephalopod arms, tentacles, and suckers, skin papillae appear to function as muscular hydrostats. The collective action of dermal erector muscles provides both movement and structural support in the absence of rigid supporting elements. Specifically, concentric circular dermal erector muscles near the papilla's base contract and push the overlying tissue upward and away from the mantle surface, while horizontally arranged dermal erector muscles pull the papilla's perimeter toward its center and determine its shape. Each papilla has a white tip, which is produced by structural light reflectors (leucophores and iridophores) that lie between the papilla's muscular core and the skin layer that contains the pigmented chromatophores. In extended papillae, the connective tissue layer appeared thinner above the papilla's apex than in surrounding areas. This result suggests that papilla extension might create tension in the overlying connective tissue and chromatophore layers, storing energy for elastic retraction. Numerous, thin subepidermal muscles form a meshwork between the chromatophore layer

  7. High hydrostatic pressure processing reduces the glycemic index of fresh mango puree in healthy subjects.

    Science.gov (United States)

    Elizondo-Montemayor, Leticia; Hernández-Brenes, Carmen; Ramos-Parra, Perla A; Moreno-Sánchez, Diana; Nieblas, Bianca; Rosas-Pérez, Aratza M; Lamadrid-Zertuche, Ana C

    2015-04-01

    Dietary guidelines recommend the daily consumption of fruits; however, healthy and type 2 diabetes mellitus (T2DM) subjects receive conflicting messages regarding ingestion of fruits, such as mango, because of its sugar content. We investigated the effects of high hydrostatic pressure (HHP) processing of fresh mango puree (MP) on the glycemic indexes (GIs) and postprandial glycemic responses of 38 healthy Mexican subjects in a randomized cross-over clinical trial. Physicochemical characterization of MP included sugar profiles by HPLC-ELSD, starch, fibers, moisture, viscosity, swelling capacity and solubility properties of alcohol insoluble residue (AIR). The mean GI for HHP-MP was significantly lower (32.7 ± 13.4) than that of unprocessed-MP (42.7 ± 19.5). A significantly higher proportion of subjects showed a low GI following the consumption of HHP-MP compared to unprocessed-MP and none of them showed a high GI for the HHP-MP, compared to a significantly higher proportion for the unprocessed-MP. The viscosity and AIR solubility values of HHP-MP samples were significantly higher, which influenced glucose peaking later (Tmax) at 45 minutes and induced 20% lower AUC values than unprocessed-MP, corresponding to greater retardation indexes. The study findings support data stating that low GI fruits are appropriate for glycemic control and that mango may be included as part of healthy subjects' diets and potentially T2DM subjects' diets. Furthermore, HHP processing of mango may offer additional benefits for glycemic control, as its performance regarding GI, AUC and Tmax was significantly better than that of the unprocessed-MP. To our knowledge, this is the first report on the impact of this commercial non-thermal pasteurization technology on glucose metabolism.

  8. Effect of hydrostatic pressure of various magnitudes on osteoarthritic chondrocytes exposed to IL-1beta.

    Science.gov (United States)

    Fioravanti, Antonella; Collodel, Giulia; Petraglia, Angela; Nerucci, Fabiola; Moretti, Elena; Galeazzi, Mauro

    2010-08-01

    Several in vitro studies have shown the importance of mechanical compression or hydrostatic pressure (HP) as a modulator of cartilage metabolism. The present study was undertaken to evaluate the in vitro effects of cyclical low HP (1-5 MPa) and continuous high HP (24 MPa) applied in the presence or absence of interleukin (IL)-1beta on human osteoarthritis (OA) chondrocytes. Chondrocytes obtained from OA cartilage were cultivated for 48 h and then exposed to pressurization in the presence or absence of IL-1beta. After pressurization, the culture medium was collected to detect the amount of proteoglycans (PG) and nitric oxide (NO) and the chondrocytes were immediately fixed for transmission electron microscopy (TEM) and processed for immunocytochemistry to localize the inducible nitric oxide synthase (iNOS). A significant increase in the level of PG and a small, non-significant, decrease in NO production were observed upon exposure to cyclical low HP. On the other hand, exposure to continuous high HP resulted in a significant decrease in the PG levels and a significant increase in NO production. The presence of IL-1beta led to a significant decrease in PG levels as well as a significant increase in NO production. The cyclical low HP did not increase the PG levels significantly but caused a statistically significant decrease in NO production in cultures damaged with IL-1beta. The continuous high HP in chondrocyte cultures stimulated with IL-1beta did not significantly decrease PG production, but significantly increased NO production. The results concerning metabolic production were further confirmed by morphological findings obtained by TEM and immunocytochemical studies. The findings of this study confirmed that the response of chondrocytes varies with magnitude and frequency of HP. These findings are important to understand aetiopathogenetic mechanisms of OA and to find out which type of physical activity may be best suited for the prevention and therapy of OA.

  9. Pressure-induced stiffness of Au nanoparticles to 71 GPa under quasi-hydrostatic loading.

    Science.gov (United States)

    Hong, Xinguo; Duffy, Thomas S; Ehm, Lars; Weidner, Donald J

    2015-12-09

    The compressibility of nanocrystalline gold (n-Au, 20 nm) has been studied by x-ray total scattering using high-energy monochromatic x-rays in the diamond anvil cell under quasi-hydrostatic conditions up to 71 GPa. The bulk modulus, K0, of the n-Au obtained from fitting to a Vinet equation of state is ~196(3) GPa, which is about 17% higher than for the corresponding bulk materials (K0: 167 GPa). At low pressures (GPa), the compression behavior of n-Au shows little difference from that of bulk Au. With increasing pressure, the compressive behavior of n-Au gradually deviates from the equation of state (EOS) of bulk gold. Analysis of the pair distribution function, peak broadening and Rietveld refinement reveals that the microstructure of n-Au is nearly a single-grain/domain at ambient conditions, but undergoes substantial pressure-induced reduction in grain size until 10 GPa. The results indicate that the nature of the internal microstructure in n-Au is associated with the observed EOS difference from bulk Au at high pressure. Full-pattern analysis confirms that significant changes in grain size, stacking faults, grain orientation and texture occur in n-Au at high pressure. We have observed direct experimental evidence of a transition in compressional mechanism for n-Au at ~20 GPa, i.e. from a deformation dominated by nucleation and motion of lattice dislocations (dislocation-mediated) to a prominent grain boundary mediated response to external pressure. The internal microstructure inside the nanoparticle (nanocrystallinity) plays a critical role for the macro-mechanical properties of nano-Au.

  10. Hydrostatic pressure acts to stabilise a chondrogenic phenotype in porcine joint tissue derived stem cells

    Directory of Open Access Journals (Sweden)

    T Vinardell

    2012-02-01

    Full Text Available Hydrostatic pressure (HP is a key component of the in vivo joint environment and has been shown to enhance chondrogenesis of stem cells. The objective of this study was to investigate the interaction between HP and TGF-β3 on both the initiation and maintenance of a chondrogenic phenotype for joint tissue derived stem cells. Pellets generated from porcine chondrocytes (CCs, synovial membrane derived stem cells (SDSCs and infrapatellar fat pad derived stem cells (FPSCs were subjected to 10 MPa of cyclic HP (4 h/day and different concentrations of TGF-β3 (0, 1 and 10 ng/mL for 14 days. CCs and stem cells were observed to respond differentially to both HP and TGF-β3 stimulation. HP in the absence of TGF-β3 did not induce robust chondrogenic differentiation of stem cells. At low concentrations of TGF-β3 (1 ng/mL, HP acted to enhance chondrogenesis of both SDSCs and FPSCs, as evident by a 3-fold increase in Sox9 expression and a significant increase in glycosaminoglycan accumulation. In contrast, HP had no effect on cartilage-specific matrix synthesis at higher concentrations of TGF-β3 (10 ng/mL. Critically, HP appears to play a key role in the maintenance of a chondrogenic phenotype, as evident by a down-regulation of the hypertrophic markers type X collagen and Indian hedgehog in SDSCs irrespective of the cytokine concentration. In the context of stem cell based therapies for cartilage repair, this study demonstrates the importance of considering how joint specific environmental factors interact to regulate not only the initiation of chondrogenesis, but also the development of a stable hyaline-like repair tissue.

  11. High hydrostatic pressure modification of whey protein concentrate for improved functional properties.

    Science.gov (United States)

    Lim, S-Y; Swanson, B G; Clark, S

    2008-04-01

    Whey protein concentrate (WPC) has many applications in the food industry. Previous research demonstrated that treatment of whey proteins with high hydrostatic pressure (HHP) can enhance solubility and foaming properties of whey proteins. The objective of this study was to use HHP to improve functional properties of fresh WPC, compared with functional properties of reconstituted commercial whey protein concentrate 35 (WPC 35) powder. Fluid whey was ultrafiltered to concentrate proteins and reconstituted to equivalent total solids (8.23%) as reconstituted commercial WPC 35 powder. Solutions of WPC were treated with 300 and 400 MPa (0- and 15-min holding time) and 600 MPa (0-min holding time) pressure. After HHP, the solubility of the WPC was determined at both pH 4.6 and 7.0 using UDY and BioRad protein assay methods. Overrun and foam stability were determined after protein dispersions were whipped for 15 min. The protein solubility was greater at pH 7.0 than at pH 4.6, but there were no significant differences at different HHP treatment conditions. The maintenance of protein solubility after HHP indicates that HHP-treated WPC might be appropriate for applications to food systems. Untreated WPC exhibited the smallest overrun percentage, whereas the largest percentage for overrun and foam stability was obtained for WPC treated at 300 MPa for 15 min. Additionally, HHP-WPC treated at 300 MPa for 15 min acquired larger overrun than commercial WPC 35. The HHP treatment of 300 MPa for 0 min did not improve foam stability of WPC. However, WPC treated at 300 or 400 MPa for 15 min and 600 MPa for 0 min exhibited significantly greater foam stability than commercial WPC 35. The HHP treatment was beneficial to enhance overrun and foam stability of WPC, showing promise for ice cream and whipping cream applications.

  12. Effect of high hydrostatic pressure on mycelial development, spore viability and enzyme activity of Penicillium Roqueforti.

    Science.gov (United States)

    Martínez-Rodríguez, Yamile; Acosta-Muñiz, Carlos; Olivas, Guadalupe I; Guerrero-Beltrán, José; Rodrigo-Aliaga, Dolores; Mujica-Paz, Hugo; Welti-Chanes, Jorge; Sepulveda, David R

    2014-01-03

    This study investigated the effect of high hydrostatic pressure treatments on mycelial development, spore viability, and total proteolytic and lipolytic activity of Penicillium roqueforti PV-LYO 10 D. Fungus growing in liquid medium was pressure-treated at 300, 400, and 500 MPa for 10 min at 20°C following seven days of incubation at 25°C and analyzed periodically up to day 9 after treatments to evaluate the effect on fungal growth. Mycelial mass of P. roqueforti was significantly affected at all pressure treatments evaluated, being 15.48%, 22.28%, 30.03%, and 12.53% lower than controls on day 1, 3, 6, and 9 after 300 MPa treatment, respectively. In a similar way, at 400 and 500 MPa, mycelial mass was 31.08% and 60.34% lower than controls one day after treatments and 49.74% and 80.85% lower on day 9, respectively. The viability of P. roqueforti spores decreased by 36.53% at 300 MPa, and complete inactivation took place at ≥400 MPa from an initial count of 7 log cfu/mL. Total proteolytic activity was not significantly affected at 300 MPa but was reduced by 18.22% at 400 MPa and by 43.18% at 500 MPa. Total lipolytic activity also decreased as the intensity of the pressure treatments increased. 21.69%, 39.12%, and 56.26% activity reductions were observed when treatments of 300, 400 and 500 MPa were applied, respectively. The results from this study show that pressure treatments are able to control growth, inactivate spores, and alter enzyme activity of P. roqueforti, which could be of interest in extending the shelf-life of blue-veined cheeses and other food products. © 2013.

  13. Acceleration of a Semi Implicit Non-hydrostatic Atmospheric Model on Many Core Architecture

    Science.gov (United States)

    Abdi, D. S.; Giraldo, F.; Wilcox, L.; Warburton, T.

    2016-12-01

    The Non-hydrostatic Unified Model of the Atmosphere (NUMA) uses high-order continuous and discontinuous Galerkin spatial discretization that result in high arithmetic intensity per-degree of freedom. Therefore, these methods are suitable for the future many-core and multi-core supercomputers with heterogeneous computing units. In our previous work, we have presented scalability of NUMA using explicit time integration that performed well on a GPU cluster. We achieved two orders of magnitude speedup over the CPU version of NUMA, while maintaining a 90% weak scaling efficiency using up to 16384 GPUs of the titan supercomputer. However, in operational numerical weather prediction, it is often necessary to use semi-implicit time integrators that allow for a much larger time step than explicit time integrators. A lot of machinery is required to enable semi-implcit time integration on the GPU and other accelerators. In this work, we will present the work on porting of the semi-implicit time integrators 1D and 3D IMEX, that require solving a system of linear equations at each time step. The scalability of the semi-implicit NUMA will be tested on supercomputers consisting of different accelerators such as CPUs, GPUs, KNL. The porting of NUMA to many-core architecture is done using a unified language called OCCA - that takes a `write once run everywhere' approach for different accelerators. To be able to scale well on future exa-scale supercomputers with heterogeneous accelerators, NUMA should be portable in-terms of both code and performance across different devices. The OCCA language's design is such that a node-per-thread approach is used on the GPU while an element-per-thread approach is used on the CPU. This makes OCCA highly performance portable and achieve results equalling that obtained with a native language (e.g. OpenMP or CUDA).

  14. Decontamination of seeds for seed sprout production by high hydrostatic pressure.

    Science.gov (United States)

    Wuytack, Elke Y; Diels, Ann M J; Meersseman, Katelijne; Michiels, Chris W

    2003-06-01

    Garden cress, sesame, radish, and mustard seeds immersed in water were treated with high pressure (250, 300, 350, and 400 MPa) for 15 min at 20 degrees C. After treatment, percentages of seeds germinating on water agar were recorded for up to 11 days. Of the seeds tested, radish seeds were found to be the most pressure sensitive, with seeds treated at 250 MPa reaching 100% germination 9 days later than untreated control seeds did. Garden cress seeds, on the other hand, were the most pressure resistant, with seeds treated at 250 MPa reaching 100% germination 1 day later than untreated control seeds did. Garden cress sprouts from seeds treated at 250 and 300 MPa also took about 1 day longer to reach average sprout length than sprouts from untreated control seeds did, indicating that sprout growth was not retarded once germination had occurred. Garden cress seeds were inoculated with suspensions of seven different bacteria (10(7) CFU/ml) and processed with high pressure. Treatment at 300 MPa (15 min, 20 degrees C) resulted in 6-log reductions of Salmonella Typhimurium, Escherichia coli MG1655, and Listeria innocua, > 4-log reductions of Shigella flexneri and pressure-resistant E. coli LMM1010, and a 2-log reduction of Staphylococcus aureus. Enterococcus faecalis was virtually not inactivated. For suspensions of the gram-positive bacteria, similar levels of inactivation in water in the absence of garden cress seeds were found, but the inactivation of E. coil LMM1010 and S. flexneri in water in the absence of garden cress seeds was significantly less extensive. These data suggest that garden cress seeds contain a component that acts synergistically with high hydrostatic pressure against gram-negative bacteria.

  15. Effect of high hydrostatic pressure on Salmonella inoculated into creamy peanut butter with modified composition.

    Science.gov (United States)

    D'Souza, Tanya; Karwe, Mukund; Schaffner, Donald W

    2014-10-01

    Peanut butter has been associated with several large foodborne salmonellosis outbreaks. This research investigates the potential of high hydrostatic pressure processing (HPP) for inactivation of Salmonella in peanut butter of modified composition, both by modifying its water activity as well by the addition of various amounts of nisin. A cocktail of six Salmonella strains associated with peanut butter and nut-related outbreaks was used for all experiments. Different volumes of sterile distilled water were added to peanut butter to increase water activity, and different volumes of peanut oil were added to decrease water activity. Inactivation in 12% fat, light roast, partially defatted peanut flour, and peanut oil was also quantified. Nisaplin was incorporated into peanut butter at four concentrations corresponding to 2.5, 5.0, 12.5, and 25.0 ppm of pure nisin. All samples were subjected to 600 MPa for 18 min. A steady and statistically significant increase in log reduction was seen as added moisture was increased from 50 to 90%. The color of all peanut butter samples containing added moisture contents darkened after high pressure processing. The addition of peanut oil to further lower the water activity of peanut butter further reduced the effectiveness of HPP. Just over a 1-log reduction was obtained in peanut flour, while inactivation to below detection limits (2 log CFU/g) was observed in peanut oil. Nisin alone without HPP had no effect. Recovery of Salmonella after a combined nisin and HPP treatment did show increased log reduction with longer storage times. The maximum log reduction of Salmonella achieved was 1.7 log CFU/g, which was comparable to that achieved by noncycling pressure treatment alone. High pressure processing alone or with other formulation modification, including added nisin, is not a suitable technology to manage the microbiological safety of Salmonella-contaminated peanut butter.

  16. Preparation of Inactivated Human Skin Using High Hydrostatic Pressurization for Full-Thickness Skin Reconstruction.

    Directory of Open Access Journals (Sweden)

    Pham Hieu Liem

    Full Text Available We have reported that high-hydrostatic-pressure (HHP technology is safe and useful for producing various kinds of decellularized tissue. However, the preparation of decellularized or inactivated skin using HHP has not been reported. The objective of this study was thus to prepare inactivated skin from human skin using HHP, and to explore the appropriate conditions of pressurization to inactivate skin that can be used for skin reconstruction. Human skin samples of 8 mm in diameter were packed in bags filled with normal saline solution (NSS or distilled water (DW, and then pressurized at 0, 100, 150, 200 and 1000 MPa for 10 minutes. The viability of skin after HHP was evaluated using WST-8 assay. Outgrowth cells from pressurized skin and the viability of pressurized skin after cultivation for 14 days were also evaluated. The pressurized skin was subjected to histological evaluation using hematoxylin and eosin staining, scanning electron microscopy (SEM, immunohistochemical staining of type IV collagen for the basement membrane of epidermis and capillaries, and immunohistochemical staining of von Willebrand factor (vWF for capillaries. Then, human cultured epidermis (CE was applied on the pressurized skin and implanted into the subcutis of nude mice; specimens were subsequently obtained 14 days after implantation. Skin samples pressurized at more than 200 MPa were inactivated in both NSS and DW. The basement membrane and capillaries remained intact in all groups according to histological and immunohistological evaluations, and collagen fibers showed no apparent damage by SEM. CE took on skin pressurized at 150 and 200 MPa after implantation, whereas it did not take on skin pressurized at 1000 MPa. These results indicate that human skin could be inactivated after pressurization at more than 200 MPa, but skin pressurized at 1000 MPa had some damage to the dermis that prevented the taking of CE. Therefore, pressurization at 200 MPa is optimal for

  17. Effect of quasi-hydrostatical radial pressure on Ic of Nb3Sn wires

    Science.gov (United States)

    Mondonico, G.; Seeber, B.; Ferreira, A.; Bordini, B.; Oberli, L.; Bottura, L.; Ballarino, A.; Flükiger, R.; Senatore, C.

    2012-11-01

    High-performance Nb3Sn conductors are intended to be used in large-scale magnets like the International Thermonuclear Experimental Reactor (ITER) and in the upgrade of the Large Hadron Collider (LHC). Due to the occurrence of high electromagnetic forces, a detailed knowledge of the response of the critical current to the three-dimensional mechanical loads acting on the wires inside the cables is required. A detailed analysis of transverse stress effects on the critical current for powder-in-tube and bronze route Nb3Sn wires is presented. In an earlier publication, we have described the effect of transverse stress exerted on a Nb3Sn wire by means of two parallel plates. In the present paper, we analyse the effect of transverse stress exerted simultaneously by four walls on a wire being confined in a U-shaped groove. In order to get a more realistic picture of the situation of wires embedded in a Rutherford cable, the compression by four walls was also performed after impregnating the wire with epoxy in the same U-shaped groove. The result is very different from the case of pressing by means of two walls: the effect of pressure on Ic is now strongly reduced, which is attributed to the almost hydrostatic pressure in the U-shaped groove. This is further confirmed by the comparison between the effects of axial and transverse loads on the upper critical field and the pinning force. The present data are also compared against the effects of mechanical load on the critical current of cables in large-scale magnets.

  18. A 3-D Finite-Volume Non-hydrostatic Icosahedral Model (NIM)

    Science.gov (United States)

    Lee, Jin

    2014-05-01

    The Nonhydrostatic Icosahedral Model (NIM) formulates the latest numerical innovation of the three-dimensional finite-volume control volume on the quasi-uniform icosahedral grid suitable for ultra-high resolution simulations. NIM's modeling goal is to improve numerical accuracy for weather and climate simulations as well as to utilize the state-of-art computing architecture such as massive parallel CPUs and GPUs to deliver routine high-resolution forecasts in timely manner. NIM dynamic corel innovations include: * A local coordinate system remapped spherical surface to plane for numerical accuracy (Lee and MacDonald, 2009), * Grid points in a table-driven horizontal loop that allow any horizontal point sequence (A.E. MacDonald, et al., 2010), * Flux-Corrected Transport formulated on finite-volume operators to maintain conservative positive definite transport (J.-L, Lee, ET. Al., 2010), *Icosahedral grid optimization (Wang and Lee, 2011), * All differentials evaluated as three-dimensional finite-volume integrals around the control volume. The three-dimensional finite-volume solver in NIM is designed to improve pressure gradient calculation and orographic precipitation over complex terrain. NIM dynamical core has been successfully verified with various non-hydrostatic benchmark test cases such as internal gravity wave, and mountain waves in Dynamical Cores Model Inter-comparisons Projects (DCMIP). Physical parameterizations suitable for NWP are incorporated into NIM dynamical core and successfully tested with multimonth aqua-planet simulations. Recently, NIM has started real data simulations using GFS initial conditions. Results from the idealized tests as well as real-data simulations will be shown in the conference.

  19. Design on high-temperature and high-pressure integral forging hydrostatic testing valve%高温高压整体锻制水压试验阀的设计

    Institute of Scientific and Technical Information of China (English)

    罗小龙; 石梦

    2011-01-01

    介绍了水压试验阀的应用,分析了整体锻造水压试验阀结构特点、工作原理及性能,给出了水压试验阀的设计计算方法及使用注意事项。%Introduces the application of hydrostatic testing valve,analyse the structure,principle and performance of forging hydrostatic testing valve,propose the calculation methods of hydrostatic testing valve and attentions,emphasize the importance of forging hydrostatic testing valve used in power plant.

  20. Exact solutions of atmospheric (3+1-dimensional nonlinear incompressible non-hydrostatic Boussinesq equations with viscosity

    Directory of Open Access Journals (Sweden)

    Ping Liu

    2015-08-01

    Full Text Available The symmetry reduction equations, similarity solutions, sub-groups and exact solutions of the (3+1-dimensional nonlinear incompressible non-hydrostatic Boussinesq equations with viscosity (INHBV equations, which describe the atmospheric gravity waves, are researched in this paper. Calculation on symmetry shows that the equations are invariant under the Galilean transformations, scaling transformations, rotational transformations and space-time translations. Three types of symmetry reduction equations and similar solutions for the (3+1-dimensional INHBV equations are proposed. Traveling wave solutions of the INHBV equations are demonstrated by means of symmetry method. The evolutions on the wind velocities and temperature perturbation are demonstrated by figures.

  1. Exact solutions of atmospheric (3+1)-dimensional nonlinear incompressible non-hydrostatic Boussinesq equations with viscosity

    Science.gov (United States)

    Liu, Ping; Zeng, Bao-Qing; Deng, Bo-Bo; Yang, Jian-Rong

    2015-08-01

    The symmetry reduction equations, similarity solutions, sub-groups and exact solutions of the (3+1)-dimensional nonlinear incompressible non-hydrostatic Boussinesq equations with viscosity (INHBV equations), which describe the atmospheric gravity waves, are researched in this paper. Calculation on symmetry shows that the equations are invariant under the Galilean transformations, scaling transformations, rotational transformations and space-time translations. Three types of symmetry reduction equations and similar solutions for the (3+1)-dimensional INHBV equations are proposed. Traveling wave solutions of the INHBV equations are demonstrated by means of symmetry method. The evolutions on the wind velocities and temperature perturbation are demonstrated by figures.

  2. Extraction of ginsenosides from fresh ginseng roots (Panax ginseng C.A. Meyer) using commercial enzymes and high hydrostatic pressure.

    Science.gov (United States)

    Sunwoo, Hoon H; Kim, Chong-Tai; Kim, Do-Yeon; Maeng, Jin-Soo; Cho, Chang-Won; Lee, Soo-Jeong

    2013-07-01

    A combination of high hydrostatic pressure (HHP) and enzymatic hydrolysis (HHP-EH) was applied for the extraction of ginsenosides from fresh ginseng roots (Panax ginseng C.A. Myer). The highest yield of ginsenosides was obtained by using a mixture of three enzymes (Celluclast + Termamyl + Viscozyme) along with HHP (100 MPa, at 50 °C for 12 h) in comparison to control samples (no enzymes, atmosphere pressure, P enzyme activity. Thus HHP-EH significantly improves the extraction of ginsenosides from fresh ginseng roots.

  3. Energy balance in the solar transition region. II - Effects of pressure and energy input on hydrostatic models

    Science.gov (United States)

    Fontenla, J. M.; Avrett, E. H.; Loeser, R.

    1991-01-01

    The radiation of energy by hydrogen lines and continua in hydrostatic energy-balance models of the transition region between the solar chromosphere and corona is studied using models which assume that mechanical or magnetic energy is dissipated in the hot corona and is then transported toward the chromosphere down the steep temperature gradient of the transition region. These models explain the average quiet sun and also the entire range of variability of the Ly-alpha lines. The relations between the downward energy flux, the pressure of the transition region, and the different hydrogen emission are described.

  4. Effects of high hydrostatic pressure on emulsifying properties of sweet potato protein in model protein-hydrocolloids system.

    Science.gov (United States)

    Khan, Nasir Mehmood; Mu, Tai-Hua; Ali, Farman; Arogundade, Lawrence A; Khan, Zia Ullah; Zhang, Maio; Ahmad, Shujaat; Sun, Hong-Nan

    2015-02-15

    The effects of high hydrostatic pressure (HHP) on emulsifying properties of sweet potato protein (SPP) in presence of 0.1%, 0.3% and 0.5% (w/v) of guar gum (GG) and glycerol monostearate (GMS) were investigated. Emulsifying stability index (ESI) of the SPP with GG revealed significant increase (Pmodel while such case was not observed for SPP-GMS model. The flow index for SPP-GG emulsion model was found to decrease with increase in HHP treatment and had non-Newtonian behaviour. The SPP-GMS emulsion models with HHP treatments showed comparatively lower viscosities but had more Newtonian flow character.

  5. Hydrostatic Pressure Effects on Structural and Electronic Properties of ETN and PETN from First-Principles Calculations.

    Science.gov (United States)

    Fedorov, Igor A; Fedorova, Tatyana P; Zhuravlev, Yuriy N

    2016-05-26

    We studied the structural and electronic properties of pentaerythritol tetranitrate (PETN) and erythritol tetranitrate (ETN) crystals within the framework of density functional theory with van der Waals interactions. The computed lattice parameters have good agreement with experimental data. Electronic and structural properties of the crystals under 0-20 GPa hydrostatic pressure were studied. The parameters of equations of state calculated from the theoretical data show good agreement with experiment within the studied pressure intervals. We have also calculated the detonation velocity and pressure.

  6. Effect of α-Amylase Degradation on Physicochemical Properties of Pre-High Hydrostatic Pressure-Treated Potato Starch

    Science.gov (United States)

    Mu, Tai-Hua; Zhang, Miao; Raad, Leyla; Sun, Hong-Nan; Wang, Cheng

    2015-01-01

    The effect of high hydrostatic pressure (HHP) on the susceptibility of potato starch (25%, w/v) suspended in water to degradation by exposure to bacterial α-amylase (0.02%, 0.04% and 0.06%, w/v) for 40 min at 25°C was investigated. Significant differences (p gelatinization). These results indicate the pre-HHP treatment of NPS leads to increased susceptibility of the granules to enzymatic degradation and eventually changes of both the amorphous and the crystalline structures. PMID:26642044

  7. Modulation of the Cardiomyocyte Contraction inside a Hydrostatic Pressure Bioreactor: In Vitro Verification of the Frank-Starling Law

    Directory of Open Access Journals (Sweden)

    Lorenzo Fassina

    2015-01-01

    Full Text Available We have studied beating mouse cardiac syncytia in vitro in order to assess the inotropic, ergotropic, and chronotropic effects of both increasing and decreasing hydrostatic pressures. In particular, we have performed an image processing analysis to evaluate the kinematics and the dynamics of those pressure-loaded beating syncytia starting from the video registration of their contraction movement. By this analysis, we have verified the Frank-Starling law of the heart in in vitro beating cardiac syncytia and we have obtained their geometrical-functional classification.

  8. Modulation of the cardiomyocyte contraction inside a hydrostatic pressure bioreactor: in vitro verification of the Frank-Starling law.

    Science.gov (United States)

    Fassina, Lorenzo; Magenes, Giovanni; Gimmelli, Roberto; Naro, Fabio

    2015-01-01

    We have studied beating mouse cardiac syncytia in vitro in order to assess the inotropic, ergotropic, and chronotropic effects of both increasing and decreasing hydrostatic pressures. In particular, we have performed an image processing analysis to evaluate the kinematics and the dynamics of those pressure-loaded beating syncytia starting from the video registration of their contraction movement. By this analysis, we have verified the Frank-Starling law of the heart in in vitro beating cardiac syncytia and we have obtained their geometrical-functional classification.

  9. Effect of Hydrostatic Pressure on Acoustic Performance of Sound Absorption Coating%静水压力下吸声覆盖层的声学性能分析

    Institute of Scientific and Technical Information of China (English)

    陶猛; 卓琳凯

    2011-01-01

    Based on the two-dimensional analytic model of sound absorption coating which contains cylindrical cavities,the effective impedance of the viscoelastic cylindrical tube was derived by considering the propagating characteristics of the lowest-order axisymmetric wave.The unit cell of sound absorption coating which contains a deformed cylindrical cavity could be approximated as the combination of several uniform cylindrical cavities,and the transmission line theory was applied to describe the unit cell so that the simplified calculation method of the acoustic performance of sound absorption coating was obtained.The finite element software was used to calculate the deformation of the unit cell under the hydrostatic pressure,and the effect of the hydrostatic pressure on the acoustic performance of sound absorption coating was evalu-ated by using the simplified calculation method.The results show that the hydrostatic pressure causes the decrease of the unit cell thickness and the cavity size,both alternations lead to the bad low-frequency sound absorption performance,and the frequency of the peak absorption coefficient being shifted to the high frequency.%基于圆柱型空腔吸声覆盖层的二维解析理论,在只考虑黏弹性圆柱管中最低阶轴对称波的条件下,推导出圆柱管的平均阻抗,将变截面圆柱型空腔腔体单元近似为截面呈阶梯变化的多个圆柱管组合,用传输线组合描述整个腔体单元,以简化吸声覆盖层声学性能参数的计算方法;利用有限元软件分析了静压条件下吸声覆盖层的腔体单元变形,结合简化计算方法分析了静压对吸声覆盖层声学性能的影响.结果表明,静压作用于吸声覆盖层引起了腔体单元厚度减小和空腔半径缩小,使得吸声覆盖层的低频吸声性能变差,且吸声峰值向高频方向偏移.

  10. Hydrostatic pressure does not cause detectable changes in survival of human retinal ganglion cells.

    Directory of Open Access Journals (Sweden)

    Andrew Osborne

    Full Text Available PURPOSE: Elevated intraocular pressure (IOP is a major risk factor for glaucoma. One consequence of raised IOP is that ocular tissues are subjected to increased hydrostatic pressure (HP. The effect of raised HP on stress pathway signaling and retinal ganglion cell (RGC survival in the human retina was investigated. METHODS: A chamber was designed to expose cells to increased HP (constant and fluctuating. Accurate pressure control (10-100 mmHg was achieved using mass flow controllers. Human organotypic retinal cultures (HORCs from donor eyes (<24 h post mortem were cultured in serum-free DMEM/HamF12. Increased HP was compared to simulated ischemia (oxygen glucose deprivation, OGD. Cell death and apoptosis were measured by LDH and TUNEL assays, RGC marker expression by qRT-PCR (THY-1 and RGC number by immunohistochemistry (NeuN. Activated p38 and JNK were detected by Western blot. RESULTS: Exposure of HORCs to constant (60 mmHg or fluctuating (10-100 mmHg; 1 cycle/min pressure for 24 or 48 h caused no loss of structural integrity, LDH release, decrease in RGC marker expression (THY-1 or loss of RGCs compared with controls. In addition, there was no increase in TUNEL-positive NeuN-labelled cells at either time-point indicating no increase in apoptosis of RGCs. OGD increased apoptosis, reduced RGC marker expression and RGC number and caused elevated LDH release at 24 h. p38 and JNK phosphorylation remained unchanged in HORCs exposed to fluctuating pressure (10-100 mmHg; 1 cycle/min for 15, 30, 60 and 90 min durations, whereas OGD (3 h increased activation of p38 and JNK, remaining elevated for 90 min post-OGD. CONCLUSIONS: Directly applied HP had no detectable impact on RGC survival and stress-signalling in HORCs. Simulated ischemia, however, activated stress pathways and caused RGC death. These results show that direct HP does not cause degeneration of RGCs in the ex vivo human retina.

  11. X-Ray Irradiated Protoplanetary Disk Atmospheres. II. Predictions from Models in Hydrostatic Equilibrium

    Science.gov (United States)

    Ercolano, Barbara; Clarke, Cathie J.; Drake, Jeremy J.

    2009-07-01

    We present new models for the X-ray photoevaporation of circumstellar disks which suggest that the resulting mass loss (occurring mainly over the radial range 10-40 AU) may be the dominant dispersal mechanism for gas around low-mass pre-main-sequence stars, contrary to the conclusions of previous workers. Our models combine use of the MOCASSIN Monte Carlo radiative transfer code and a self-consistent solution of the hydrostatic structure of the irradiated disk. We estimate the resulting photoevaporation rates assuming sonic outflow at the surface where the gas temperature equals the local escape temperature and derive mass-loss rates of ~10-9 M sun yr-1, typically a factor of 2-10 times lower than the corresponding rates in our previous work where we did not adjust the density structure of the irradiated disk. The somewhat lower rates, and the fact that mass loss is concentrated toward slightly smaller radii, result from the puffing up of the heated disk at a few AU which partially screens the disk at tens of AU. Our mass-loss fluxes agree with those of Alexander et al. but we differ from Alexander et al. in our assessment of the overall significance of X-ray photoevaporation, given the large disk radii (and hence emitting area) associated with X-ray-driven winds. Gorti & Hollenbach, on the other hand, predict considerably lower mass-loss fluxes than either Alexander et al. or ourselves and we discuss possible reasons for this difference. We highlight the fact that X-ray photoevaporation has two generic advantages for disk dispersal compared with photoevaporation by extreme ultraviolet (EUV) photons that are only modestly beyond the Lyman limit: the demonstrably large X-ray fluxes of young stars even after they have lost their disks and the fact that X-rays are effective at penetrating much larger columns of material close to the star. We however stress that our X-ray-driven mass-loss rates are considerably more uncertain than the corresponding rates for EUV

  12. The Three-Dimensional Finite-Volume Non-Hydrostatic Icosahedral Model (NIM)

    Science.gov (United States)

    Lee, J. L.; MacDonald, A. E.

    2014-12-01

    A multi-scales Non-hydrostatic Icosahedral Model (NIM) has been developed at Earth System Research Laboratory (ESRL) to meet NOAA's future prediction mission ranging from mesoscale short-range, high-impact weather forecasts to longer-term intra-seasonal climate prediction. NIM formulates the latest numerical innovation of the three-dimensional finite-volume control volume on the quasi-uniform icosahedral grid suitable for ultra-high resolution simulations. NIM is designed to utilize the state-of-art computing architecture such as Graphic Processing Units (GPU) processors to run globally at kilometer scale resolution to explicitly resolve convective storms and complex terrains. The novel features of NIM numerical design include: 1.1. A local coordinate system upon which finite-volume integrations are undertaken. The use of a local Cartesian coordinate greatly simplifies the mathematic formulation of the finite-volume operators and leads to the finite-volume integration along straight lines on the plane, rather than along curved lines on the spherical surface. 1.2. A general indirect addressing scheme developed for modeling on irregular grid. It arranges the icosahedral grid with a one-dimensional vector loop structure, table specified memory order, and an indirect addressing scheme that yields very compact code despite the complexities of this grid. 1.3. Use of three-dimensional finite-volume integration over control volumes constructed on the height coordinates. Three-dimensional finite-volume integration accurately represents the Newton Third Law over terrain and improves pressure gradient force over complex terrain. 1.4. Use of the Runge-Kutta 4th order conservative and positive-definite transport scheme 1.5. NIM dynamical solver has been implemented on CPU as well as GPU. As one of the potential candidates for NWS next generation models, NIM dynamical core has been successfully verified with various benchmark test cases including those proposed by DCMIP

  13. Fate of Staphylococcus aureus in cheese treated by ultrahigh pressure homogenization and high hydrostatic pressure.

    Science.gov (United States)

    López-Pedemonte, T; Brinez, W J; Roig-Sagués, A X; Guamis, B

    2006-12-01

    We evaluated the influence of ultrahigh pressure homogenization (UHPH) treatment applied to milk containing Staphylococcus aureus CECT 976 before cheese making, and the benefit of applying a further high hydrostatic pressure (HHP) treatment to cheese. The evolution of Staph. aureus counts during 30 d of storage at 8 degrees C and the formation of staphylococcal enterotoxins were also assessed. Milk containing approximately 7.3 log(10) cfu/mL of Staph. aureus was pressurized using a 2-valve UHPH machine, applying 330 and 30 MPa at the primary and the secondary homogenizing valves, respectively. Milk inlet temperatures (T(in)) of 6 and 20 degrees C were assayed. Milk was used to elaborate soft-curd cheeses (UHPH cheese), some of which were additionally submitted to 10-min HHP treatments of 400 MPa at 20 degrees C (UHPH+HHP cheese). Counts of Staph. aureus were measured on d 1 (24 h after manufacture or immediately after HHP treatment) and after 2, 15, and 30 d of ripening at 8 degrees C. Counts of control cheeses not pressure-treated were approximately 8.5 log(10) cfu/g showing no significant decreases during storage. In cheeses made from UHPH treated milk at T(in) of 6 degrees C, counts of Staph. aureus were 5.0 +/- 0.3 log(10) cfu/g at d 1; they decreased significantly to 2.8 +/- 0.2 log(10) cfu/g on d 15, and were below the detection limit (1 log(10) cfu/g) after 30 d of storage. The use of an additional HHP treatment had a synergistic effect, increasing reductions up to 7.0 +/- 0.3 log(10) cfu/g from d 1. However, for both UHPH and UHPH+HHP cheeses in the 6 degrees C T(in) samples, viable Staph. aureus cells were still recovered. For samples of the 20 degrees C T(in) group, complete inactivation of Staph. aureus was reached after 15 d of storage for both UHPH and UHPH+HHP cheese. Staphylococcal enterotoxins were found in controls but not in UHPH or UHPH+HHP treated samples. This study shows a new approach for significantly improving cheese safety by means of

  14. The nonlinear optical rectification and second harmonic generation in asymmetrical Gaussian potential quantum well: Effects of hydrostatic pressure, temperature and magnetic field

    Science.gov (United States)

    Liu, Xin; Zou, LiLi; Liu, Chenglin; Zhang, Zhi-Hai; Yuan, Jian-Hui

    2016-03-01

    In the present work, the effects of hydrostatic pressure, temperature, and magnetic field on the nonlinear optical rectification (OR) and second-harmonic generation (SHG) in asymmetrical Gaussian potential quantum well (QW) have been investigated theoretically. Here, the expressions for the optical properties are calculated by the compact-density-matrix approach and iterative method. Simultaneously, the energy eigenvalues and their corresponding eigenfunctions have been obtained by using the finite difference method. The energy eigenvalues and the shape of the confined potential are modulated by the hydrostatic pressure, temperature, and magnetic field. So the results of a number of numerical experiments indicate that the nonlinear OR and SHG strongly depends on the hydrostatic pressure, temperature, and magnetic field. This gives a new degree of freedom in various device applications based on the intersubband transitions of electrons.

  15. Photoluminescence energy transitions in GaAs-Ga{sub 1-x}Al{sub x}As double quantum wells: Electric and magnetic fields and hydrostatic pressure effects

    Energy Technology Data Exchange (ETDEWEB)

    Lopez, S.Y. [Grupo de Educacion en Ciencias Experimentales y Matematicas-GECEM, Facultad de Educacion, Universidad de Antioquia, AA 1226 Medellin (Colombia); Mora-Ramos, M.E. [Facultad de Ciencias, Universidad Autonoma del Estado de Morelos, Av. Universidad 1001, CP 62209, Cuernavaca, Morelos (Mexico); Duque, C.A., E-mail: cduque@fisica.udea.edu.c [Instituto de Fisica, Universidad de Antioquia, AA 1226 Medellin (Colombia)

    2009-12-15

    The photoluminescence energy transitions in GaAs-Ga{sub 1-x}Al{sub x}As coupled double quantum wells are presented by considering the simultaneous effects of applied electric and magnetic fields and hydrostatic pressure. Calculations have been made in the framework of the effective mass and parabolic band approximations and using a variational procedure. The electric field is taken to be oriented along the growth direction of the heterostructure whereas for the magnetic field both in-plane and in-growth directions have been considered. The results show that the hydrostatic pressure and the applied electric field are two useful tools to tune the direct and indirect exciton transitions in such heterostructures. Our results are in good agreement with previous experimental findings in double quantum wells under applied electric field and hydrostatic pressure.

  16. Magnetic characterization of non-ideal single-domain monoclinic pyrrhotite and its demagnetization under hydrostatic pressure up to 2 GPa with implications for impact demagnetization

    Science.gov (United States)

    Bezaeva, Natalia S.; Chareev, Dmitriy A.; Rochette, Pierre; Kars, Myriam; Gattacceca, Jérôme; Feinberg, Joshua M.; Sadykov, Ravil A.; Kuzina, Dilyara M.; Axenov, Sergey N.

    2016-08-01

    Here we present a comprehensive magnetic characterization of synthesized non-ideal single-domain (SD) monoclinic pyrrhotite (Fe7S8). The samples were in the form of a powder and a powder dispersed in epoxy. "Non-ideal" refers to a powder fraction of predominantly SD size with a minor contribution of small pseudo-single-domain grains; such non-ideal SD pyrrhotite was found to be a remanence carrier in several types of meteorites (carbonaceous chondrites, SNC…), which justifies the usage of synthetic compositions as analogous to natural samples. Data were collected from 5 to 633 K and include low-field magnetic susceptibility (χ0), thermomagnetic curves, major hysteresis loops, back-field remanence demagnetization curves, first-order reversal curves (FORCs), alternating field and pressure demagnetization of saturation isothermal remanent magnetization (SIRM), low temperature data (such as zero-field-cooled and field-cooled remanence datasets together with room temperature SIRM cooling-warming cycles) as well as XRD and Mössbauer spectra. The characteristic Besnus transition is observed at ∼33 K. FORC diagrams indicate interacting SD grains. The application of hydrostatic pressure up to 2 GPa using nonmagnetic high-pressure cells resulted in the demagnetization of the sample by 32-38%. Repeated cycling from 1.8 GPa to atmospheric pressure and back resulted in a total remanence decrease of 44% (after 3 cycles). Pressure demagnetization experiments have important implications for meteorite paleomagnetism and suggest that some published paleointensities of meteorites with non-ideal SD monoclinic pyrrhotite as remanence carrier may be lower limits because shock demagnetization was not accounted for.

  17. A diagnostic interface for the ICOsahedral Non-hydrostatic (ICON) modelling framework based on the Modular Earth Submodel System (MESSy v2.50)

    Science.gov (United States)

    Kern, Bastian; Jöckel, Patrick

    2016-10-01

    Numerical climate and weather models have advanced to finer scales, accompanied by large amounts of output data. The model systems hit the input and output (I/O) bottleneck of modern high-performance computing (HPC) systems. We aim to apply diagnostic methods online during the model simulation instead of applying them as a post-processing step to written output data, to reduce the amount of I/O. To include diagnostic tools into the model system, we implemented a standardised, easy-to-use interface based on the Modular Earth Submodel System (MESSy) into the ICOsahedral Non-hydrostatic (ICON) modelling framework. The integration of the diagnostic interface into the model system is briefly described. Furthermore, we present a prototype implementation of an advanced online diagnostic tool for the aggregation of model data onto a user-defined regular coarse grid. This diagnostic tool will be used to reduce the amount of model output in future simulations. Performance tests of the interface and of two different diagnostic tools show, that the interface itself introduces no overhead in form of additional runtime to the model system. The diagnostic tools, however, have significant impact on the model system's runtime. This overhead strongly depends on the characteristics and implementation of the diagnostic tool. A diagnostic tool with high inter-process communication introduces large overhead, whereas the additional runtime of a diagnostic tool without inter-process communication is low. We briefly describe our efforts to reduce the additional runtime from the diagnostic tools, and present a brief analysis of memory consumption. Future work will focus on optimisation of the memory footprint and the I/O operations of the diagnostic interface.

  18. 沿海地区大型储罐工程海水充水试验防腐蚀技术%Anti-corrosion Technology in Hydrostatic Testing Using Sea Water for Large Oil Terminals in Coastal Areas

    Institute of Scientific and Technical Information of China (English)

    张国军; 李宁

    2011-01-01

    In the last several years, large oil terminals began to be built in the coastal areas in China. In the project implementation, the successful application of anti-corrosion technology, which is an important part of the project, has a direct impact on the service life of the project and total project costs. On the basis of the north area project of Dalian International Oil Reserve Terminal of Petrochina, the project and is briefly described and specific application of anti-corrosion technology is detailed. In the project, sea water is used for the hydrostatic testing of tanks, Alsacrficing anode is installed together with A1 alloy anodes to prevent corrosion. The characteristics of the technology are summarized. The practice shows that the application of this technology has not only ensured the good results of hydrostatic tests but also reduced the project costs.%近年来,国内开始在沿海地区兴建大型石油储罐工程,在整个工程中,防腐技术应用是否得当关系着工程的使用寿命以及总体成本,是整个工程非常重要的一个环节。以大连中石油国际储备库北区工程为例,对该项防腐技术的具体应用流程进行了详细的论述,介绍了在储罐充水试验中应用海水介质,采用了铝制一次性牺牲阳极,配合铝合金阳极块的防腐技术,不仅能保证充水试验效果,同时也有效地降低了工程成本。

  19. Study of flux pinning mechanism under hydrostatic pressure in optimally doped (Ba,K)Fe2As2 single crystals.

    Science.gov (United States)

    Shabbir, Babar; Wang, Xiaolin; Ma, Y; Dou, S X; Yan, S S; Mei, L M

    2016-03-17

    Strong pinning depends on the pinning force strength and number density of effective defects. Using the hydrostatic pressure method, we demonstrate here that hydrostatic pressure of 1.2 GPa can significantly enhance flux pinning or the critical current density (Jc) of optimally doped Ba0.6K0.4Fe2As2 crystals by a factor of up to 5 in both low and high fields, which is generally rare with other Jc enhancement techniques. At 4.1 K, high pressure can significantly enhance Jc from 5 × 10(5 )A/cm(2) to nearly 10(6 )A/cm(2) at 2 T, and from 2 × 10(5 )A/cm(2) to nearly 5.5 × 10(5 )A/cm(2) at 12 T. Our systematic analysis of the flux pinning mechanism indicates that both the pinning centre number density and the pinning force are greatly increased by the pressure and enhance the pinning. This study also shows that superconducting performance in terms of flux pinning or Jc for optimally doped superconducting materials can be further improved by using pressure.

  20. Modulating optical rectification, second and third harmonic generation of doped quantum dots: Interplay between hydrostatic pressure, temperature and noise

    Science.gov (United States)

    Ganguly, Jayanta; Saha, Surajit; Bera, Aindrila; Ghosh, Manas

    2016-10-01

    We examine the profiles of optical rectification (OR), second harmonic generation (SHG) and third harmonic generation (THG) of impurity doped QDs under the combined influence of hydrostatic pressure (HP) and temperature (T) in presence and absence of Gaussian white noise. Noise has been incorporated to the system additively and multiplicatively. In order to study the above nonlinear optical (NLO) properties the doped dot has been subjected to a polarized monochromatic electromagnetic field. Effect of application of noise is nicely reflected through alteration of peak shift (blue/red) and variation of peak height (increase/decrease) of above NLO properties as temperature and pressure are varied. All such changes again sensitively depends on mode of application (additive/multiplicative) of noise. The remarkable influence of interplay between noise strength and its mode of application on the said profiles has also been addressed. The findings illuminate fascinating role played by noise in tuning above NLO properties of doped QD system under the active presence of both hydrostatic pressure and temperature.

  1. Multi-Layer Hydrostatic Equilibrium of Planets and Synchronous Moons: Theory and Application to Ceres and to Solar System Moons

    CERN Document Server

    Tricarico, Pasquale

    2013-01-01

    The hydrostatic equilibrium of multi-layer bodies lacks a satisfactory theoretical treatment despite its wide range of applicability. Here we show that by using the exact analytical potential of homogeneous ellipsoids we can obtain recursive analytical solutions and an exact numerical method for the hydrostatic equilibrium shape problem of multi-layer planets and synchronous moons. The recursive solutions rely on the series expansion of the potential in terms of the polar and equatorial shape eccentricities, while the numerical method uses the exact potential expression. These solutions can be used to infer the interior structure of planets and synchronous moons from the observed shape, rotation, and gravity. When applied to dwarf planet Ceres, we show that it is most likely a differentiated body with an icy crust of equatorial thickness 30-90 km and a rocky core of density 2.4-3.1 g/cm$^3$. For synchronous moons, we show that the $J_2/C_{22} \\simeq 10/3$ and the $(b-c)/(a-c) \\simeq 1/4$ ratios have significa...

  2. Combined influence of hydrostatic pressure and temperature on interband emission energy of impurity doped quantum dots in presence of noise

    Science.gov (United States)

    Bera, Aindrila; Ghosh, Manas

    2016-11-01

    We explore the profiles of interband emission energy (IEE) of impurity doped quantum dots (QDs) under the simultaneous influence of hydrostatic pressure (HP) and temperature (T) and in presence and absence of Gaussian white noise. Noise has been incorporated to the system additively and multiplicatively. In this regard, modulation of IEE by the variation of several other relevant quantities such as electric field, magnetic field, confinement potential, dopant location, dopant potential and aluminium concentration has also been investigated. Gradual alteration of HP and T affects IEE discernibly. Inclusion of noise has been found to enhance or deplete the IEE depending upon its mode of application. Moreover, under given conditions of temperature and pressure, the difference between the impurity-free ground state energy and the binding energy appears to be crucial in determining whether or not the profiles of IEE would resemble that of binding energy. The findings reveal fascinating role played by noise in tailoring the IEE of doped QD system under conspicuous presence of hydrostatic pressure and temperature.

  3. The pericellular environment regulates cytoskeletal development and the differentiation of mesenchymal stem cells and determines their response to hydrostatic pressure

    Directory of Open Access Journals (Sweden)

    AJ Steward

    2013-02-01

    Full Text Available The objective of this study was to examine the interplay between matrix stiffness and hydrostatic pressure (HP in regulating chondrogenesis of mesenchymal stem cells (MSCs and to further elucidate the mechanotransductive roles of integrins and the cytoskeleton. MSCs were seeded into 1 %, 2 % or 4 % agarose hydrogels and exposed to cyclic hydrostatic pressure. In a permissive media, the stiffer hydrogels supported an osteogenic phenotype, with little evidence of chondrogenesis observed regardless of the matrix stiffness. In a chondrogenic media, the stiffer gels suppressed cartilage matrix production and gene expression, with the addition of RGDS (an integrin blocker found to return matrix synthesis to similar levels as in the softer gels. Vinculin, actin and vimentin organisation all adapted within stiffer hydrogels, with the addition of RGDS again preventing these changes. While the stiffer gels inhibited chondrogenesis, they enhanced mechanotransduction of HP. RGDS suppressed the mechanotransduction of HP, suggesting a role for integrin binding as a regulator of both matrix stiffness and HP. Intermediate filaments also appear to play a role in the mechanotransduction of HP, as only vimentin organisation adapted in response to this mechanical stimulus. To conclude, the results of this study demonstrate that matrix density and/or stiffness modulates the development of the pericellular matrix and consequently integrin binding and cytoskeletal structure. The study further suggests that physiological cues such as HP enhance chondrogenesis of MSCs as the pericellular environment matures and the cytoskeleton adapts, and points to a novel role for vimentin in the transduction of HP.

  4. Hydrostatic pressure effect on the electron mobility in a ZnSe/Zn1-xCdxSe strained heterojunction

    Institute of Scientific and Technical Information of China (English)

    Bai Xian-Ping; Ban Shi-Liang

    2008-01-01

    With a memory function approach, this paper investigates the electronic mobility parallel to the interface in a ZnSe/Zn1-xCdxSe strained heterojunction under hydrostatic pressure by considering the intersubband and intrasubband scattering from the optical phonon modes. A triangular potential approximation is adopted to simplify the potential of the conduction band bending in the channel side and the electronic penetrating into the barrier is considered by a finite interface potential in the adopted model. The numerical results with and without strain effect are compared and analysed. Meanwhile, the properties of electronic mobility under pressure versus temperature, Cd concentration and electronic density are also given and discussed, respectively. It shows that the strain effect lowers the mobility of electrons while the hydrostatic pressure effect is more obvious to decrease the mobility. The contribution induced by the longitudinal optical phonons in the channel side is dominant to decide the mobility. Compared with the intrasubband scattering it finds that the effect of intersubband scattering is also important for the studied material.

  5. The strength of ruby from X-ray diffraction under non-hydrostatic compression to 68 GPa

    Science.gov (United States)

    Dong, Haini; Dorfman, Susannah M.; Wang, Jianghua; He, Duanwei; Duffy, Thomas S.

    2014-07-01

    Polycrystalline ruby (α-Al2O3:Cr3+), a widely used pressure calibrant in high-pressure experiments, was compressed to 68.1 GPa at room temperature under non-hydrostatic conditions in a diamond anvil cell. Angle-dispersive X-ray diffraction experiments in a radial geometry were conducted at beamline X17C of the National Synchrotron Light Source. The stress state of ruby at high pressure and room temperature was analyzed based on the measured lattice strain. The differential stress of ruby increases with pressure from ~3.4 % of the shear modulus at 18.5 GPa to ~6.5 % at 68.1 GPa. The polycrystalline ruby sample can support a maximum differential stress of ~16 GPa at 68.1 GPa under non-hydrostatic compression. The results of this study provide a better understanding of the mechanical properties of this important material for high-pressure science. From a synthesis of existing data for strong ceramic materials, we find that the high-pressure yield strength correlates well with the ambient pressure Vickers hardness.

  6. Hydrostatic pressure effect on the superconducting properties of BaBi3 and SrBi3 single crystals

    Science.gov (United States)

    Jha, Rajveer; Avila, Marcos A.; Ribeiro, Raquel A.

    2017-02-01

    We demonstrate the superconducting properties of, and hydrostatic pressure effect on, BaBi3 and SrBi3 superconductors. We measure the dc magnetic susceptibility under hydrostatic pressure for both compounds, which shows a positive pressure coefficient of dT c/dP = 1.22 K GPa-1 for BaBi3 and a negative pressure coefficient of dT c/dP = -0.43 K GPa-1 for SrBi3. The normal state electrical resistivity shows that both compounds are highly metallic in nature. The upper critical fields H c2 evaluated by resistivity under magnetic fields ρ(T,H) are 22 kOe for BaBi3 and 2.9 kOe for SrBi3. A specific heat jump of ΔC e/γT c = 1.05 suggests weak coupling superconductivity in BaBi3, whereas ΔC e/γT c = 2.08 for SrBi3 is higher than the Bardeen-Cooper-Schrieffer theory value of 1.43, indicating a strong coupling superconductor.

  7. Effect of High Hydrostatic Pressure Processing Strategies on Retention of Antioxidant Phenolic Bioactives in Foods and Beverages – a Review

    Directory of Open Access Journals (Sweden)

    Tokuşoğlu Özlem

    2016-12-01

    Full Text Available Phenolic compounds, especially flavonoids have health-promoting benefits that play some important roles in foods as visual appearance, taste, aroma and represent an abundant antioxidant component of the human and animal diet. High hydrostatic pressure processing (HHPP conditions (300–700 MPa at moderate initial temperatures (around ambient are generally sufficient to inactivate vegetative pathogens for pasteurization processes, some enzymes, or spoilage organisms to extend the shelf-life. The aim of the review is to reveal the effect of high hydrostatic pressure processing strategies on the retention of antioxidant phenolic bioactives in foods and beverages. HHPP can increase extraction capacity of phenolic constituents, and ensure higher levels of preserved bioactive constituents. High pressure extraction (HPE can shorten processing times, provide higher extraction yields while having less negative effects on the structure and antioxidant activity of bioactive constituents. HPE enhances mass transfer rates, increases cell permeability, increases diffusion of phenolics and retains higher levels of bioactive compounds. Total phenolics in HHPP-treated foods were either unaffected or actually increased in concentration and/or extractability following treatment with high pressure.

  8. Cells under pressure - treatment of eukaryotic cells with high hydrostatic pressure, from physiologic aspects to pressure induced cell death.

    Science.gov (United States)

    Frey, Benjamin; Janko, Christina; Ebel, Nina; Meister, Silke; Schlücker, Eberhard; Meyer-Pittroff, Roland; Fietkau, Rainer; Herrmann, Martin; Gaipl, Udo S

    2008-01-01

    The research on high hydrostatic pressure in medicine and life sciences is multifaceted. According to the used pressure head the research has to be divided into two different parts. To study physiological aspects of pressure on eukaryotic cells physiological pressure (pHHP; highly reversible alterations and normally does not affect cellular viability. The treatment of eukaryotic cells with non-physiological pressure (HHP; > or = 100 MPa) reveals different outcomes. Treatment with HHP or = 200 MPa. Moreover, HHP treatment with > 300 MPa leads to necrosis. Therefore, HHP plays a role for the sterilisation of human transplants, of food stuff, and pharmaceuticals. Human tumour cells subjected to HHP > 300 MPa display a necrotic phenotype along with a gelificated cytoplasm, preserve their shape, and retain their immunogenicity. These observations favour the use of HHP to produce whole cell based tumour vaccines. Further experiments revealed that the increment of pressure as well as the pressure holding time influences the cell death of tumour cells. We conclude that high hydrostatic pressure offers both, an economic, easy to apply, clean, and fast technique for the generation of vaccines, and a promising tool to study physiological aspects.

  9. An implicit wetting and drying approach for non-hydrostatic baroclinic flows in high aspect ratio domains

    Science.gov (United States)

    Candy, A. S.

    2017-04-01

    A new approach to modelling free surface flows is developed that enables, for the first time, 3D consistent non-hydrostatic baroclinic physics that wets and drys in the large aspect ratio spatial domains that characterise geophysical systems. This is key in the integration of physical models to permit seamless simulation in a single consistent arbitrarily unstructured multiscale and multi-physics dynamical model. A high order continuum representation is achieved through a general Galerkin finite element formulation that guarantees local and global mass conservation, and consistent tracer advection. A flexible spatial discretisation permits conforming domain bounds and a variable spatial resolution, whilst atypical use of fully implicit time integration ensures computational efficiency. Notably this brings the natural inclusion of non-hydrostatic baroclinic physics and a consideration of vertical inertia to flood modelling in the full 3D domain. This has application in improving modelling of inundation processes in geophysical domains, where dynamics proceeds over a large range of horizontal extents relative to vertical resolution, such as in the evolution of a tsunami, or in urban environments containing complex geometric structures at a range of scales.

  10. Effects of high hydrostatic pressure and temperature increase on Escherichia coli spp. and pectin methyl esterase inactivation in orange juice.

    Science.gov (United States)

    Torres, E F; González-M, G; Klotz, B; Rodrigo, D

    2016-03-01

    The aim of this study was to evaluate the effect of high hydrostatic pressure treatment combined with moderate processing temperatures (25 ℃-50 ℃) on the inactivation of Escherichia coli O157: H7 (ATCC 700728), E. coli K12 (ATCC 23716), and pectin methyl esterase in orange juice, using pressures of 250 to 500 MPa with times ranging between 1 and 30 min. Loss of viability of E. coli O157:H7 increased significantly as pressure and treatment time increased, achieving a 6.5 log cycle reduction at 400 MPa for 3 min at 25 ℃ of treatment. With regard to the inactivation of pectin methyl esterase, the greatest reduction obtained was 90.05 ± 0.01% at 50 ℃ and 500 MPa of pressure for 15 min; therefore, the pectin methyl esterase enzyme was highly resistant to the treatments by high hydrostatic pressure. The results obtained in this study showed a synergistic effect between the high pressure and moderate temperatures in inactivating E. coli cells.

  11. An Impact Study of the Vertical Coordinate on a Non-hydrostatic Mesoscale High-Resolution Model

    Institute of Scientific and Technical Information of China (English)

    LI Xingliang; CHEN Dehui

    2006-01-01

    With the high-speed development of high-powered computer techniques, it is possible that a highresolution and multi-scale unified numerical model is applied to the operational weather prediction. Some techniques about mesoscale non-hydrostatic numerical weather prediction are addressed, and the impact of the vertical coordinate system is one of them. Based on WRF (Weather Research and Forecasting) model,the influence of vertical coordinates on the non-hydrostatic mesoscale high-resolution model is compared.The results show that the error of various coordinates in lower levels is almost same when we use the geometry height (z) and the pressure (p) to set up a terrain-following coordinate; but the error of the height terrain-following coordinate in higher levels is smaller than that of the pressure terrain-following coordinate.The higher the resolution is, the bigger the error will be. The results of the high-resolution simulation exhibited that the trend of the difference in the two coordinates existed. In addition, the correlative coefficient and standard error are also analysed by the comparison between the forecast fields and the corresponding analysis fields.

  12. Synthetic photometry for M and K giants and stellar evolution: hydrostatic dust-free model atmospheres and chemical abundances

    Science.gov (United States)

    Aringer, B.; Girardi, L.; Nowotny, W.; Marigo, P.; Bressan, A.

    2016-04-01

    Based on a grid of hydrostatic spherical COMARCS models for cool stars, we have calculated observable properties of these objects, which will be mainly used in combination with stellar evolution tracks and population synthesis tools. The high-resolution opacity sampling and low-resolution convolved spectra as well as bolometric corrections for a large number of filter systems are made electronically available. We exploit those data to study the effect of mass, C/O ratio and nitrogen abundance on the photometry of K and M giants. Depending on effective temperature, surface gravity and the chosen wavelength ranges, variations of the investigated parameters cause very weak to moderate and, in the case of C/O values close to 1, even strong shifts of the colours. For the usage with stellar evolution calculations, they will be treated as correction factors applied to the results of an interpolation in the main quantities. When we compare the synthetic photometry to observed relations and to data from the Galactic bulge, we find in general a good agreement. Deviations appear for the coolest giants showing pulsations, mass-loss and dust shells, which cannot be described by hydrostatic models.

  13. Genes required for growth at high hydrostatic pressure in Escherichia coli K-12 identified by genome-wide screening.

    Science.gov (United States)

    Black, S Lucas; Dawson, Angela; Ward, F Bruce; Allen, Rosalind J

    2013-01-01

    Despite the fact that much of the global microbial biosphere is believed to exist in high pressure environments, the effects of hydrostatic pressure on microbial physiology remain poorly understood. We use a genome-wide screening approach, combined with a novel high-throughput high-pressure cell culture method, to investigate the effects of hydrostatic pressure on microbial physiology in vivo. The Keio collection of single-gene deletion mutants in Escherichia coli K-12 was screened for growth at a range of pressures from 0.1 MPa to 60 MPa. This led to the identification of 6 genes, rodZ, holC, priA, dnaT, dedD and tatC, whose products were required for growth at 30 MPa and a further 3 genes, tolB, rffT and iscS, whose products were required for growth at 40 MPa. Our results support the view that the effects of pressure on cell physiology are pleiotropic, with DNA replication, cell division, the cytoskeleton and cell envelope physiology all being potential failure points for cell physiology during growth at elevated pressure.

  14. The influence of hydrostatic pressure on the magnetic and magnetocaloric properties of DyRu2Si2

    Science.gov (United States)

    Saleheen, Ahmad Us; Samanta, Tapas; Khan, Mojammel; Adams, Philip W.; Young, David P.; Dubenko, Igor; Ali, Naushad; Stadler, Shane

    2017-01-01

    We report the magnetic and magnetocaloric properties of the tetragonal rare-earth compound DyRu2Si2 under applied hydrostatic pressure. The isothermal entropy change ( ΔS ) and the adiabatic temperature change ( ΔTad ) were calculated from magnetization data collected at different applied pressures and from heat capacity measurements conducted at atmospheric pressure, respectively. The application of hydrostatic pressure significantly modified the multi-step magnetization curve and the saturation magnetization. A suppression of the magnetization was observed for P = 0.588 GPa and P = 0.654 GPa whereas, at about P ≈1 GPa, the saturation magnetization increased and the magnetization isotherms again resembled the curves measured at atmospheric pressure. A small thermal hysteresis was observed between the heating and cooling M(T) curves at Tt=3.4 K , with an applied magnetic field of H = 0.1 T. This thermal hysteresis indicates a first-order like transition which was also supported by the Arrott plot analysis. The volume magnetostriction was estimated from the pressure-dependent magnetization measurements using a Maxwell relation.

  15. Study of Hydrostatic Oil Chamber of Turning Carriage%旋转刀架静压油室的研制

    Institute of Scientific and Technical Information of China (English)

    王华程; 王虹

    2014-01-01

    Whirlwind carriage is the key part of big crank shaft machining. In order to guarantee the turning precision of tool plate, there is a support of both way inner cycle 72 points constant flow hydrostatic bearing shoe between tool plate and carriage. And it forms oil film, when crank machining, tool plate floats by oil film to achieve no fric-tion turning. The weak link of hydrostatic film rigidity is analyzing, calculating, comparing, and improving through finite element modeling to ensure machining precision of crank shaft.%旋转刀架是加工大型曲轴拐颈关键部件,为保证旋转刀盘回转精度,刀盘与刀架中间内设双向内循环72点恒流式静压轴瓦支承,静压轴瓦之间形成油膜,在车削曲轴时,靠静压油膜将刀盘浮升,以达到无摩擦转动的目的。通过有限元建模计算,对静压油腔油膜刚度进行分析、计算、比较,改进薄弱环节,最终保证了曲轴的加工精度。

  16. Nonlinear stability of pulsational mode of gravitational collapse in self-gravitating hydrostatically bounded dust molecular cloud

    Indian Academy of Sciences (India)

    P K Karmakar

    2011-06-01

    The pulsational mode of gravitational collapse (PMGC) in a hydrostatically bounded dust molecular cloud is responsible for the evolution of tremendous amount of energy during star formation. The source of free energy for this gravito-electrostatic instability lies in the associated self-gravity of the dispersed phase of relatively huge dust grains of solid matter over the gaseous phase of background plasma. The nonlinear stability of the same PMGC in an infinite dusty plasma model (plane geometry approximation for large wavelength fluctuation in the absence of curvature effects) is studied in a hydrostatic kind of homogeneous equilibrium configuration. By the standard reductive perturbation technique, a Korteweg–de Vries (KdV) equation for investigating the nonlinear evolution of the lowest order perturbed self-gravitational potential is developed in a time-stationary (steady-state) form, which is studied analytically as well as numerically. Different nonlinear structures (soliton-like and soliton chain-like) are found to exist in different situations. Astrophysical situations, relevant to it, are briefly discussed.

  17. First-principles calculations of optical properties of GeC, SnC and GeSn under hydrostatic pressure

    Energy Technology Data Exchange (ETDEWEB)

    Sahnoun, M. [Applied Materials Laboratory (AML), Electronics Department, University of Sidi-Bel-Abbes, 22000 (Algeria); Khenata, R. [Applied Materials Laboratory (AML), Electronics Department, University of Sidi-Bel-Abbes, 22000 (Algeria)]. E-mail: khenata_rabah@yahoo.fr; Baltache, H. [Applied Materials Laboratory (AML), Electronics Department, University of Sidi-Bel-Abbes, 22000 (Algeria); Rerat, M. [Laboratoire de Chimie Theorique et Physico-Chimie Moleculaire, UMR 5624, Universite de Pau, 64000 Pau (France)]. E-mail: michel.rerat@univ-pau.fr; Driz, M. [Laboratoire de Physique Quantique et de Modelisation Mathematique (LPQ3M), Departement de Technologie, Universite de Mascara, 29000 (Algeria); Bouhafs, B. [Computational Materials Science Laboratory, Physics Department, University of Sidi-Bel-Abbes, 22000 (Algeria); Abbar, B. [Computational Materials Science Laboratory, Physics Department, University of Sidi-Bel-Abbes, 22000 (Algeria)

    2005-01-31

    We present first-principles of the full-potential linearized augmented plane wave calculations of the effect of hydrostatic pressure on the optical properties of zinc-blende GeC, SnC and GeSn compounds. The refractive index and its variation with hydrostatic pressure are well described. An accurate calculation of linear optical functions (refraction index and its pressure derivative, and both imaginary and real parts of the dielectric function) is performed in the photon energy range up to 15 eV. The predicted optical constants agree well with the available experimental and theoretical ones.

  18. High-pressure behavior of cristobalite under quasi-hydrostatic conditions

    Science.gov (United States)

    Cernok, Ana; Bykova, Elena; Liermann, Hanns-Peter; Dubrovinsky, Leonid

    2014-05-01

    Cristobalite is a high-temperature, low-pressure polymorph of SiO2. It is comprised of a framework of SiO4 tetrahedra, like many other low-pressure silica polymorphs, e.g. quartz tridymite, or coesite. Its cubic form known as β-cristobalite crystallizes above 1470 ° C and at atmospheric pressure. The tetragonal α-phase is a metastable polymorph which appears upon cooling of the cubic β-cristobalite to ambient temperature and it can be found in natural acidic volcanic rocks. High-pressure behavior of α-cristobalite is of interest form the geological standpoint because it was experimentally observed that under elevated pressures and at ambient temperature this polymorph with 4-fold coordinated silicon can transform to seifertite - a lower mantle phase with octahedrally coordinated Si. The transformational sequence is as follows. The tetragonal α-cristobalite transforms to a monoclinic cristobalite II near ~1.5 GPa upon hydrostatic compression. The structure of this higher-pressure polymorph was recently solved. Above ~10 GPa cristobalite II is found to transforms to cristobalite X-I. Apart from the recent determination of the unit cell parameters, the structure of the cristobalite X-I still remains unknown. Further compression of cristobalite X-I above pressures exceeding ~35 GPa leads to formation of cristobalite X-II, which is the polymorph reported to have the structure of seifertite. However, there is a large discrepancy among various experimental observations regarding the pressure at which this transition takes place. Motivated by the recent studies, we aim at understanding how the structure of this "bridging phase", cristobalite X-I, is evolving under pressure and how it transforms to the seifertite phase. We performed in-situ single crystal Raman spectroscopy and X-ray diffraction up to 82 GPa in steps of 3-5 GPa. We used diamond-anvil cells with 250 μm diamond culet size and neon as the pressure-transmitting medium. In-situ Raman spectra indicated the

  19. High hydrostatic pressure influences the in vitro response to xenobiotics in Dicentrarchus labrax liver

    Energy Technology Data Exchange (ETDEWEB)

    Lemaire, Benjamin; Mignolet, Eric; Debier, Cathy [Institut des Sciences de la Vie, Université Catholique de Louvain, Croix du Sud 2, B-1348 Louvain-la-Neuve (Belgium); Calderon, Pedro Buc [Louvain Drug Research Institute, Université Catholique de Louvain, Avenue Mounier 73, B-1200 Woluwé-Saint-Lambert (Belgium); Thomé, Jean Pierre [Laboratoire d’Ecologie Animale et Ecotoxicologie, Université de Liège, Allée du 6 août 15, B-4000 Liège (Belgium); Rees, Jean François, E-mail: jf.rees@uclouvain.be [Institut des Sciences de la Vie, Université Catholique de Louvain, Croix du Sud 2, B-1348 Louvain-la-Neuve (Belgium)

    2016-04-15

    Highlights: • The methodology of precision-cut liver slices was applied to the European seabass. • Liver slices remained viable and functional in short-term co-exposure studies. • CYP1A induction was blocked in slices exposed to an AhR agonist at high pressure. • HSP70 induction was lower in slices exposed to an AhR agonist at high pressure. • Oxidative stress responses to tBHP were less pronounced at high pressure. - Abstract: Hydrostatic pressure (HP) increases by about 1 atmosphere (0.1 MPa) for each ten-meter depth increase in the water column. This thermodynamical parameter could well influence the response to and effects of xenobiotics in the deep-sea biota, but this possibility remains largely overlooked. To grasp the extent of HP adaptation in deep-sea fish, comparative studies with living cells of surface species exposed to chemicals at high HP are required. We initially conducted experiments with precision-cut liver slices of a deep-sea fish (Coryphaenoides rupestris), co-exposed for 15 h to the aryl hydrocarbon receptor (AhR) agonist 3-methylcholanthrene at HP levels representative of the surface (0.1 MPa) and deep-sea (5–15 MPa; i.e., 500–1500 m depth) environments. The transcript levels of a suite of stress-responsive genes, such as the AhR battery CYP1A, were subsequently measured (Lemaire et al., 2012; Environ. Sci. Technol. 46, 10310–10316). Strikingly, the AhR agonist-mediated increase of CYP1A mRNA content was pressure-dependently reduced in C. rupestris. Here, the same co-exposure scenario was applied for 6 or 15 h to liver slices of a surface fish, Dicentrarchus labrax, a coastal species presumably not adapted to high HP. Precision-cut liver slices of D. labrax were also used in 1 h co-exposure studies with the pro-oxidant tert-butylhydroperoxide (tBHP) as to investigate the pressure-dependence of the oxidative stress response (i.e., reactive oxygen production, glutathione and lipid peroxidation status). Liver cells remained

  20. PCR结合表型鉴定对超高压处理后的冷藏带鱼细菌菌相分析%Microbial ecology ofTrichiurus lepturus of haitail pretreated by high hydrostatic pressure during cold storage based on phenotypic and 16S rRNA gene analysis

    Institute of Scientific and Technical Information of China (English)

    谢晶; 刘骁; 杨茜; 钱韵芳; 张新林

    2016-01-01

    The effect of high hydrostatic pressure (290 MPa, 6 min) on microbial ecology changes ofTrichiurus lepturus during vacuum-packaged storage (12 d) was studied via 16S rRNA gene sequencing analysis and phenotypic methods. The microbial colonies of aerobic culture and anaerobic culture, which were obtained from 5 microflora’s growth stages (including freshTrichiurus lepturus, freshTrichiurus lepturus which were stored under 4℃ for 4, 8 and 12 d after high hydrostatic pressure treatment), were isolated and purified by the tryptic soy agar medium and tryptic soy broth medium, repeatedly classified by the traditional phenotypic methods (morphological, physiological and biochemical characteristics of bacteria strains), and then the bacteria DNA of pure culture was extracted and amplified by the polymerase chain reaction (PCR). Finally, 24 bacteria strains of aerobic culture and anaerobic culture in the vacuum-packaged Trichiurus lepturus under the 4℃cold storage were obtained. The result showed thatPseudomonas brenneri,Pseudomonas fulva andPsychrobacter faecalis which appeared in the initial microflora of freshTrichiurus lepturus were inactivated and non-existent after the high hydrostatic pressure treatment; 5 bacteria strains (includingShewanella baltica,Pseudomonas lundensis,Stenotrophomonas rhizophila,Staphylococcus epidermidis andMicrobacterium oxydans) gradually reduced and disappeared after the high hydrostatic pressure treatment. Three bacteria strains gradually grew with the extension of storage time, which were Microbacterium halimionae,Macrococcus caseolyticus andRhizobium larrymoorei. In the whole process of storage after the high hydrostatic pressure treatment, 4 bacteria strains (Moraxella osloensis,Kocuria rhizophila,Carnobacterium maltaromaticum andDermacoccus nishinomiyaensis) always existed, and they were not sensitive to the high hydrostatic pressure treatment. EspeciallyCarnobacterium maltaromaticum, which had a high proportion of total bacteria

  1. Hydrostatic Mooring System. Final Technical Report: Main Report plus Appendices A, B, and C - Volume 1 and 2

    Energy Technology Data Exchange (ETDEWEB)

    Jens Korsgaard

    2000-08-08

    The main conclusions from the work carried out under this contract are: An ordinary seafarer can learn by training on a simulator, to moor large tanker vessels to the Hydrostatic Mooring, safely and quickly, in all weather conditions up to storms generating waves with a significant wave height of 8 m. Complete conceptual design of the Hydrostatic Mooring buoy was carried out which proved that the buoy could be constructed entirely from commercially available standard components and materials. The design is robust, and damage resistant. The mooring tests had a 100% success rate from the point of view of the buoy being securely attached and moored to the vessel following every mooring attempt. The tests had an 80% success rate from the point of view of the buoy being adequately centered such that petroleum transfer equipment on the vessel could be attached to the corresponding equipment on the buoy. The results given in Table 3-2 of the mooring tests show a consistently improving performance from test to test by the Captain that performed the mooring operations. This is not surprising, in view of the fact that the Captain had only three days of training on the simulator prior to conducting the tests, that the maneuvering required is non-standard, and the test program itself lasted four days. One conclusion of the test performance is that the Captain was not fully trained at the initiation of the test. It may therefore be concluded that a thoroughly trained navigator would probably be able to make the mooring such that the fluid transfer equipment can be connected with reliability in excess of 90%. Considering that the typical standard buoy has enough power aboard to make eight mooring attempts, this implies that the probability that the mooring attempt should fail because of the inability to connect the fluid transfer equipment is of the order of 10{sup {minus}8}. It may therefore be concluded that the mooring operation between a Hydrostatic Mooring and a large

  2. Development of the Non-Hydrostatic Jupiter Global Ionosphere Thermosphere Model (J-GITM): Status and Current Simulations

    Science.gov (United States)

    Bougher, Stephen; Ridley, Aaron; Majeed, Tariq; Waite, J. Hunter; Gladstone, Randy; Bell, Jared

    2016-07-01

    The primary objectives for development and validation of a new 3-D non-hydrostatic model of Jupiter's upper atmosphere is to improve our understanding of Jupiter's thermosphere-ionosphere-magnetosphere system and to provide a global context within which to analyze the data retrieved from the new JUNO mission. The new J-GITM model presently incorporates the progress made on the previous Jupiter-TGCM code (i.e. key parameterizations, ion-neutral chemistry, IR cooling) while also employing the non-hydrostatic numerical core of the Earth Global Ionosphere-Thermosphere Model (GITM). The GITM numerical framework has been successfully applied to Earth, Mars, and Titan (see Ridley et al. [2006], Bougher et al. [2015], Bell [2008, 2010]). Moreover, it has been shown to simulate the effects of strong, localized heat sources (such as joule heating and auroral heating) more accurately than strictly hydrostatic GCMs (Deng et al. [2007, 2008]). Thus far, in the J-GITM model development and testing, model capability has been progressively augmented to capture the neutral composition (e.g. H, H2, He major species), 3-component neutral winds, and thermal structure, as well as the ion composition (H3+, H2+, and H+ among others) above 250 km. Presently, J-GITM: (a) provides an interactive calculation for auroral particle precipitation (i.e. heating, ionization), an improvement over the static formulation used previously in the J-TGCM (Bougher et al., 2005; Majeed et al., 2005, 2009, 2015); (b) self-consistently calculates an ionosphere using updated ion-neutral chemistry, ion dynamics, and electron transport; (c) simulates the chemistry that forms key hydrocarbons at the base of the thermosphere, focusing on CH4, C2H2, and C2H6; (d) allows the production of H3+, CH4, C2H2, and C2H6 to modify the global thermal balance of Jupiter through their non-LTE radiative cooling; (e) provides a calculation of H2 vibrational chemistry to regulate H+ densities; and (f) uses the improved

  3. High hydrostatic pressure: a new way to improve in vitro developmental competence of porcine matured oocytes after vitrification

    DEFF Research Database (Denmark)

    Du, Y; Pribenszky, C S; Molnár, M

    2008-01-01

    The purpose of the present study was to improve cryotolerance using high hydrostatic pressure (HHP) pretreatment of porcine in vitro matured (IVM) oocytes, to facilitate their further developmental competence after parthenogenetic activation. A total of 1668 porcine IVM oocytes were used in our...

  4. 机床静压导轨毛细管节流器的设计%Design of Capillary Restrictor in Machine Tool Hydrostatic Guideway

    Institute of Scientific and Technical Information of China (English)

    杨卓

    2016-01-01

    随着机械制造业的发展,高精度机床的需求不断加大。介绍静压导轨在机床上的应用与分类,以及静压导轨毛细管节流器的参数计算。通过合理设计静压导轨节流器,保证导轨间隙在一定载荷范围内变化最小和液压静压导轨具有良好的直线运动精度。%With the development of machinery manufacturing industry, demand for high⁃precision machine tools is increased. The application and classification of the hydrostatic guideway in machine, parameter calculation of hydrostatic guideway capillary restrictor were presented. Through rational design of hydrostatic guideway restrictor, the gap between the guide rails is ensured minimum in a cer⁃tain load range and the hydraulic hydrostatic guideway has a good linear precision.

  5. Effects of an Intense Laser Field and Hydrostatic Pressure on the Intersubband Transitions and Binding Energy of Shallow Donor Impurities in a Quantum Well

    Institute of Scientific and Technical Information of China (English)

    U. Yesilgul; F. Ungan; E. Kasapoglu; H. Sari; I. S(o)kmen

    2011-01-01

    We have calculated the intersubband transitions and the ground-state binding energies of a hydrogenic donor impurity in a quantum well in the presence of a high-frequency laser field and hydrostatic pressure.The calculations are performed within the effective mass approximation,using a variational method. We conclude that the laser field amplitude and the hydrostatic pressure provide an important effect on the electronic and optical properties of the quantum wells.According to the results obtained from the present work,it is deduced that (i) the binding energies of donor impurity decrease as the laser field increase,(ii) the binding energies of donor impurity increase as the hydrostatic pressure increase,(iii) the intersubband absorption coefficients shift toward lower energies as the hydrostatic pressure increases,(iv) the magnitude of absorption coefficients decrease and also shift toward higher energies as the laser field increase.It is hopeful that the obtained results will provide important improvements in device applications.

  6. Vibrational spectroscopy at very high pressures. Part 28. Raman and far-infrared spectra of some complex chlorides A2MCl6 under hydrostatic pressure

    DEFF Research Database (Denmark)

    Adams, David M.; Berg, Rolf W.; Williams, Alan D.

    1981-01-01

    Raman and far-IR mode frequency shifts with pressure have been observed under hydrostatic conditions in a gasketed diamond anvil cell (d.a.c.). Using compressibilities calculated from unit cell constants and lattice energies, Grüneisen parameters gammai have been obtained for all observed modes...

  7. Piezochromic luminescence behaviors of two new benzothiazole-enamido boron difluoride complexes: intra- and inter-molecular effects induced by hydrostatic compression.

    Science.gov (United States)

    Wang, Xiaoqing; Liu, Qingsong; Yan, Hui; Liu, Zhipeng; Yao, Mingguang; Zhang, Qingfu; Gong, Shuwen; He, Weijiang

    2015-05-01

    Two new propeller-shaped benzothiazole-enamide boron difluoride complexes exhibiting piezochromic luminescence upon mechanical grinding or hydrostatic compression were prepared. The two analogues displayed the red shift in luminescence under high pressure, while compound 2 with ICT effects showed a more sensitive piezochromic response at low pressure (<1.5 GPa). The different piezochromic luminescence behaviors of these compounds were investigated.

  8. Membrane damage and viability loss of thermally treated and high hydrostatic pressurized E. coli 0157:H7 and Salmonella spp. in apple juice

    Science.gov (United States)

    Differences in membrane damage including leakage of intracellular UV-materials and loss of viability of Salmonella spp. and Escherichia coli O157:H7 bacteria in apple juice following thermal death time disk (TDT) and high hydrostatic pressure treatments were investigated. Salmonella and E. coli O157...

  9. Hydrostatic pressure promotes the proliferation and osteogenic/chondrogenic differentiation of mesenchymal stem cells: The roles of RhoA and Rac1

    Directory of Open Access Journals (Sweden)

    Yin-Hua Zhao

    2015-05-01

    Full Text Available Our previous studies have shown that hydrostatic pressure can serve as an active regulator for bone marrow mesenchymal stem cells (BMSCs. The current work further investigates the roles of cytoskeletal regulatory proteins Ras homolog gene family member A (RhoA and Ras-related C3 botulinum toxin substrate 1 (Rac1 in hydrostatic pressure-related effects on BMSCs. Flow cytometry assays showed that the hydrostatic pressure promoted cell cycle initiation in a RhoA- and Rac1-dependent manner. Furthermore, fluorescence assays confirmed that RhoA played a positive and Rac1 displayed a negative role in the hydrostatic pressure-induced F-actin stress fiber assembly. Western blots suggested that RhoA and Rac1 play central roles in the pressure-inhibited ERK phosphorylation, and Rac1 but not RhoA was involved in the pressure-promoted JNK phosphorylation. Finally, real-time polymerase chain reaction (PCR experiments showed that pressure promoted the expression of osteogenic marker genes in BMSCs at an early stage of osteogenic differentiation through the up-regulation of RhoA activity. Additionally, the PCR results showed that pressure enhanced the expression of chondrogenic marker genes in BMSCs during chondrogenic differentiation via the up-regulation of Rac1 activity. Collectively, our results suggested that RhoA and Rac1 are critical to the pressure-induced proliferation and differentiation, the stress fiber assembly, and MAPK activation in BMSCs.

  10. Optical spectroscopy of Al2O3:Ti3+ single crystal under hydrostatic pressure. The influence on the Jahn-Teller coupling

    NARCIS (Netherlands)

    García-Revilla, S.; Rodríguez, F.; Valiente, R.; Pollnau, M.

    2002-01-01

    This work investigates the effect of hydrostatic pressure on the excitation and emission spectra, as well as on the lifetime, of Al2O3:Ti3+ at room temperature. The aim is to establish correlations between the pressure-induced band shifts and the corresponding local structural changes undergone by t

  11. Draft genome sequence of Staphylococcus saprophyticus subsp. saprophyticus M1-1, isolated from the gills of a Korean rockfish, Sebastes schlegeli Hilgendorf, after high hydrostatic pressure processing.

    Science.gov (United States)

    Kim, Bong-Soo; Kim, Chong-Tai; Park, Bang Heon; Kwon, Sujin; Cho, Yong-Jin; Kim, Namsoo; Kim, Chul-Jin; Chun, Jongsik; Kwak, Jangyul; Maeng, Jin-Soo

    2012-08-01

    A bacterium designated M1-1 was isolated from the gills of a Korean rockfish, Sebastes schlegeli Hilgendorf, after high hydrostatic pressure processing. Studies of 16S rRNA phylogeny and comparative genomics demonstrated that the isolate belongs to Staphylococcus saprophyticus subsp. saprophyticus. Here, we report the draft genome sequence of S. saprophyticus subsp. saprophyticus M1-1 (KACC 16562).

  12. Draft Genome Sequence of Staphylococcus saprophyticus subsp. saprophyticus M1-1, Isolated from the Gills of a Korean Rockfish, Sebastes schlegeli Hilgendorf, after High Hydrostatic Pressure Processing

    OpenAIRE

    Kim, Bong-Soo; Kim, Chong-Tai; Park, Bang Heon; Kwon, Sujin; Cho, Yong-Jin; Kim, Namsoo; Kim, Chul-Jin; Chun, Jongsik; Kwak, Jangyul; Maeng, Jin-Soo

    2012-01-01

    A bacterium designated M1-1 was isolated from the gills of a Korean rockfish, Sebastes schlegeli Hilgendorf, after high hydrostatic pressure processing. Studies of 16S rRNA phylogeny and comparative genomics demonstrated that the isolate belongs to Staphylococcus saprophyticus subsp. saprophyticus. Here, we report the draft genome sequence of S. saprophyticus subsp. saprophyticus M1-1 (KACC 16562).

  13. 自加压式动静压混合式气体润滑密封的性能分析%Study on Self-pressurized Hydrostatic-dynamic Hybrid Lubrication Gas Seal

    Institute of Scientific and Technical Information of China (English)

    扈中平; 李双喜; 蔡纪宁; 张秋翔

    2011-01-01

    介绍自加压动静压混合润滑气体密封的工作原理,分析其密封特性.采用流体计算软件FLUENT建立不同自加压动静压混合气体润滑密封端面间气膜的数值计算流场,求得气膜的压力和速度分布,得到密封的性能参数,如开启力、刚度、泄漏量.分析该密封在稳定运转状态和启停工作状态的运行特点,与流体动压型气体密封的工作特性进行对比.结果表明:自加压动静压混合密封在运转时具有更大的开启力和泄漏量以及较高的刚度,表现出更好的启停性能;静压引入孔的位置以及均压槽结构对密封开启力及泄漏量有较大影响,静压引人孔在坝区使气膜刚度增大,在动压槽区则使气膜刚度减小.%The operating principle of the self-pressurized hydrostatic-dynamic hybrid lubrication gas seal (SHDHLGS)was introduced and its seal characteristic was analyzed. Different numerical calculated flow field of the gas film between the seal faces of self-pressurized hydrostatic-dynamic hybrid lubrication gas seal and dynamic pressure gas seal was established by software FLUENT. The distributions of pressure and velocity and the performance parameters of the seal such as the opening force, stiffness, and leakage distribution were obtained. The operating characteristics of this seal under stable condition and working status of the start and stop running were analyzed and compared with the operating characteristics of fluid dynamic pressure gas seal. The results show that better start and stop performance is ensured and there is a higher opening force and leakage in SHDHLGS when operating;the location of pressure introduction hole and pressure groove structure influences the opening force and leakage obviously. The gas film stiffness will increases when the pressure introduction hole locates in the dam area, and it will reduces when the pressure introduction hole locates in the pressure groove area.

  14. The ICON-1.2 hydrostatic atmospheric dynamical core on triangular grids – Part 1: Formulation and performance of the baseline version

    Directory of Open Access Journals (Sweden)

    H. Wan

    2013-06-01

    Full Text Available As part of a broader effort to develop next-generation models for numerical weather prediction and climate applications, a hydrostatic atmospheric dynamical core is developed as an intermediate step to evaluate a finite-difference discretization of the primitive equations on spherical icosahedral grids. Based on the need for mass-conserving discretizations for multi-resolution modelling as well as scalability and efficiency on massively parallel computing architectures, the dynamical core is built on triangular C-grids using relatively small discretization stencils. This paper presents the formulation and performance of the baseline version of the new dynamical core, focusing on properties of the numerical solutions in the setting of globally uniform resolution. Theoretical analysis reveals that the discrete divergence operator defined on a single triangular cell using the Gauss theorem is only first-order accurate, and introduces grid-scale noise to the discrete model. The noise can be suppressed by fourth-order hyper-diffusion of the horizontal wind field using a time-step and grid-size-dependent diffusion coefficient, at the expense of stronger damping than in the reference spectral model. A series of idealized tests of different complexity are performed. In the deterministic baroclinic wave test, solutions from the new dynamical core show the expected sensitivity to horizontal resolution, and converge to the reference solution at R2B6 (35 km grid spacing. In a dry climate test, the dynamical core correctly reproduces key features of the meridional heat and momentum transport by baroclinic eddies. In the aqua-planet simulations at 140 km resolution, the new model is able to reproduce the same equatorial wave propagation characteristics as in the reference spectral model, including the sensitivity of such characteristics to the meridional sea surface temperature profile. These results suggest that the triangular-C discretization provides a

  15. Hydrostatic pressure dependence on the collapsing of heptamer clusters in the charge ordered spinel AlV2O4

    Science.gov (United States)

    Kalavathi, S.; Vennila Raju, Selva; Chandra, Sharat; Williams, Quentin; Sahu, P. Ch.

    2017-01-01

    Charge frustrated spinels have engaged the interest of condensed matter studies due to the novel formation of multimer molecular sub units that lifts the degeneracy in the ground state. An exhaustive study on the stability of these molecular sub units is not available in the literature. In the present study, evidence has been obtained for the first time that hydrostatic pressure beyond 21 GPa, destabilizes the vanadium heptamer molecular sub units reversibly in the unique ambient temperature charge ordered spinel AlV2O4. The bulk modulus and its pressure derivative of the charge ordered phase are constrained. In addition a systematic structural analysis as a function of temperature shows destabilization of vanadium trimers those stack up to make the heptamer units. The crystal structure and total energy have been calculated using first principles density functional formalism (GGA approximation) as a function of pressure. The results obtained corroborate the stability of the frustrated phase beyond 20 GPa.

  16. Hydrostatic pressure activates ATP-sensitive K+ channels in lung epithelium by ATP release through pannexin and connexin hemichannels.

    Science.gov (United States)

    Richter, Katrin; Kiefer, Kevin P; Grzesik, Benno A; Clauss, Wolfgang G; Fronius, Martin

    2014-01-01

    Lungs of air-breathing vertebrates are constantly exposed to mechanical forces and therefore are suitable for investigation of mechanotransduction processes in nonexcitable cells and tissues. Freshly dissected Xenopus laevis lungs were used for transepithelial short-circuit current (ISC) recordings and were exposed to increased hydrostatic pressure (HP; 5 cm fluid column, modified Ussing chamber). I(SC) values obtained under HP (I(5cm)) were normalized to values before HP (I(0cm)) application (I(5cm)/I(0cm)). Under control conditions, HP decreased I(SC) (I(5cm)/I(0cm)=0.84; n=68; Plung. These data show an activation of KATP in pulmonary epithelial cells in response to HP that is induced by ATP release through mechanosensitive pannexin and connexin hemichannels. These findings represent a novel mechanism of mechanotransduction in nonexcitable cells.

  17. Partially implicit finite difference scheme for calculating dynamic pressure in a terrain-following coordinate non-hydrostatic ocean model

    Science.gov (United States)

    Liu, Zhe; Lin, Lei; Xie, Lian; Gao, Huiwang

    2016-10-01

    To improve the efficiency of the terrain-following σ-coordinate non-hydrostatic ocean model, a partially implicit finite difference (PIFD) scheme is proposed. By using explicit terms instead of implicit terms to discretize the parts of the vertical dynamic pressure gradient derived from the σ-coordinate transformation, the coefficient matrix of the discrete Poisson equation that the dynamic pressure satisfies can be simplified from 15 diagonals to 7 diagonals. The PIFD scheme is shown to run stably when it is applied to simulate five benchmark cases, namely, a standing wave in a basin, a surface solitary wave, a lock-exchange problem, a periodic wave over a bar and a tidally induced internal wave. Compared with the conventional fully implicit finite difference (FIFD) scheme, the PIFD scheme produces simulation results of equivalent accuracy at only 40-60% of the computational cost. The PIFD scheme demonstrates strong applicability and can be easily implemented in σ-coordinate ocean models.

  18. Simultaneous application of microbial transglutaminase and high hydrostatic pressure to improve heat induced gelation of pork plasma.

    Science.gov (United States)

    Fort, N; Lanier, T C; Amato, P M; Carretero, C; Saguer, E

    2008-11-01

    The effects of treating porcine plasma with microbial tranglutaminase (MTGase) under high hydrostatic pressure (HHP) were studied as a means of improving its gel-forming properties when subsequently heated at pH 5.5, near the pH of meats. Plasma containing varying levels of commercial MTGase was pressurized (400MPa, room temperature, pH 7) for different times, and adjusted to pH 5.5 prior to heating to induce gelation. MTGase-treatment under HHP led to greater enhancement of heat-induced plasma gel properties as compared to control samples. The greatest improvements were achieved by pressurising plasma with 43.3U MTGase/g protein for 30min, thereby achieving recoveries of 49% and 63% in fracture force (gel strength) and fracture distance (gel deformability) of the subsequently heat-induced gels, respectively, relative to gel properties obtained by heating untreated plasma at physiological conditions (pH 7.5).

  19. Ab initio study of the modification of elastic properties of {alpha}-iron by hydrostatic strain and by hydrogen interstitials

    Energy Technology Data Exchange (ETDEWEB)

    Psiachos, D., E-mail: dpsiachos@gmail.com [ICAMS, Ruhr-Universitaet Bochum, Bochum (Germany); Hammerschmidt, T., E-mail: thomas.hammerschmidt@icams.rub.de [ICAMS, Ruhr-Universitaet Bochum, Bochum (Germany); Drautz, R., E-mail: ralf.drautz@icams.rub.de [ICAMS, Ruhr-Universitaet Bochum, Bochum (Germany)

    2011-06-15

    The effect of hydrostatic strain and of interstitial hydrogen on the elastic properties of {alpha}-iron is investigated using ab initio density-functional theory calculations. We find that the cubic elastic constants and the polycrystalline elastic moduli to a good approximation decrease linearly with increasing hydrogen concentration. This net strength reduction can be partitioned into a strengthening electronic effect which is overcome by a softening volumetric effect. The calculated hydrogen-dependent elastic constants are used to determine the polycrystalline elastic moduli and anisotropic shear moduli. For the key slip planes in {alpha}-iron, [11-bar0] and [112-bar], we find a shear modulus reduction of approximately 1.6% per at.% H.

  20. The use of Tecnomatix software to simulate the manufacturing flows in an industrial enterprise producing hydrostatic components

    Science.gov (United States)

    Petrila, S.; Brabie, G.; Chirita, B.

    2016-08-01

    The analysis performed on manufacturing flows within industrial enterprises producing hydrostatic components twos made on a number of factors that influence smooth running of production such: distance between pieces, waiting time from one surgery to another; time achievement of setups on CNC machines; tool changing in case of a large number of operators and manufacturing complexity of large files [2]. To optimize the manufacturing flow it was used the software Tecnomatix. This software represents a complete portfolio of manufacturing solutions digital manufactured by Siemens. It provides innovation by linking all production methods of a product from process design, process simulation, validation and ending the manufacturing process. Among its many capabilities to create a wide range of simulations, the program offers various demonstrations regarding the behavior manufacturing cycles. This program allows the simulation and optimization of production systems and processes in several areas such as: car suppliers, production of industrial equipment; electronics manufacturing, design and production of aerospace and defense parts.