WorldWideScience

Sample records for hydrostatic slipper bearings

  1. FEASIBILITY STUDY OF AIR BEARING ROCKET SLED SLIPPERS

    Science.gov (United States)

    a simple self-acting type of bearing can support a typical monorail rocket sled, without contact between the slipper and the rail, at speeds between...slipper bearing is capable of preventing slipper-rail contact over the entire speed range of typical monorail and dual rail sleds. However, the weight and

  2. 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

  3. Accuracy of Spindle Units with Hydrostatic Bearings

    Directory of Open Access Journals (Sweden)

    Fedorynenko Dmytro

    2016-06-01

    Full Text Available The work is devoted to the research of precision regularities in a spindle unit by the trajectory of the spindle installed on hydrostatic bearings. The mathematical model of trajectories spindle with lumped parameters that allows to define the position of the spindle with regard the simultaneous influence of design parameters, geometrical deviations ofform, temperature deformation bearing surfaces, the random nature of operational parameters and technical loads of hydrostatic bearings has been developed. Based on the results of numerical modeling the influence of shape errors of bearing surface of hydrostatic bearing on the statistical characteristics of the radius vector trajectories of the spindle by varying the values rotational speed of the spindle and oil pressure in front hydrostatic bearing has been developed. The obtained statistical regularities of precision spindle unit have been confirmed experimentally. It has been shown that an effective way to increase the precision of spindle units is to regulate the size of the gap in hydrostatic spindle bearings. The new design of an adjustable hydrostatic bearing, which can improve the accuracy of regulation size gap has been proposed.

  4. Hydrostatic radial bearing of centrifugal pump

    International Nuclear Information System (INIS)

    Skalicky, A.

    1976-01-01

    A hydrostatic radial pump is described characterized by the fact that part of the medium off-taken from delivery is used as a lubricating medium. Two additional bodies are placed alongside a hydrostatic bearing with coils in between them and the pump shaft; the coils have an opposite pitch. The feed channel for the hydrostatic bearing pocket is linked to delivery. The coil outlets are connected to the pump suction unit. Two rotating coils placed alongside the hydrostatic bearing will considerably simplify the communication channel design and reduce the dependence on the pump shaft deflections. The addition of another rotating coil in the close vicinity of the pump shaft or directly on the shaft further increases the efficiency. The bearing can be used in designing vertical circulating pumps for the cooling circuits of nuclear reactors. (J.B.)

  5. Hydrostatic bearing with a stepped duct

    International Nuclear Information System (INIS)

    Krevsun, Eh.P.; Ivanov, A.A.

    1975-01-01

    A method for calculating and experimental data from tests on a hydrostatic bearing whose operating hydraulic channel is formed by two cylincrical surfaces, are presented. Unlike currently used hydrostatic bearings, the bearing described has no capillary choke or diaphragm choke at the entrance. This simplifies the construction and increases the reliability, especially when it is operated with corrosive liquids or liquids containing solid suspensoids and causing erosion and blockage of the choke structures. In order to obtain the calculated relations, the flow of a liquid from the bearing in the axial direction to one side through a part of an aperture of unit width was examined. The effect of rotating the axle, of flow in the circumferential direction, and curvature of the aperture was not considered. Isothermal and laminar flows were considered. Because of the simplicity of the hydraulic circuit and the satisfactory properties (bearing capability and flow rate), the bearing described may be used in pumps operating with corrosive liquids, with those containing solid suspensoids and in nuclear energy establishments. (author)

  6. External Coulomb-Friction Damping For Hydrostatic Bearings

    Science.gov (United States)

    Buckmann, Paul S.

    1992-01-01

    External friction device damps vibrations of shaft and hydrostatic ring bearing in which it turns. Does not rely on wear-prone facing surfaces. Hydrostatic bearing ring clamped in radially flexing support by side plates clamped against radial surfaces by spring-loaded bolts. Plates provide friction against radial motions of shaft.

  7. SLIPPER PERFORMANCE INVESTIGATION IN AXIAL PISTON PUMPS AND MOTORS-FLOW AND VISCOUS POWER LOSSES

    Directory of Open Access Journals (Sweden)

    A. Osman KURBAN

    1997-01-01

    Full Text Available In this study, the slippers being the most effective on the performance of swash plate type axial piston pumps and motors, which is a good example of hydrodynamic-hydrostatic bearing applications, have been investigated. With respect to this, having derived the viscous moment loss, viscous flow leakage loss and power loss equations, the variations of these parameters under different operating conditions have been examined experimentally.

  8. The design, manufacture and testing of the hydrostatic bearing for the NSF 900 analysing magnet

    International Nuclear Information System (INIS)

    Acton, W.J.; Myers, D.B.

    1978-10-01

    This report describes the design, manufacture and testing of the hydrostatic bearing which will be used to support the 90 0 analysing magnet of the 30 MV tandem electrostatic accelerator now being constructed at Daresbury Lboratory. (author)

  9. 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

    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...... of these analytical approximations are explored in order to clarify the limits of application. In conclusion, it is found that the spatial gradient of the thermal field on the bearing surface is the significant factor in the thermo-viscous effect on the hydrostatic pressure profile, which leads to the conclusion...... that design engineers need to understand the thermodynamics of hydrostatic bearings, when using the conventional simple analytical approach, neglecting thermo-piezo-viscosity, in hydrostatic pressure force calculations....

  10. The Research Status and Progress of Heavy/Large Hydrostatic Thrust Bearing

    Directory of Open Access Journals (Sweden)

    Xibing Li

    2014-03-01

    Full Text Available How to improve the rotation speed of heavy/large CNC vertical lathe, the machining efficiency, and machining precision is one of the key issues which need to be solved urgently. Hydrostatic thrust bearing is the key part to the heavy/large CNC vertical lathe; its performance directly affects the machining quality and operation efficiency. This paper analyses the latest research results from the perspective of the mechanical properties of hydrostatic thrust bearing, oil film lubrication, static pressure bearing thermal deformation, and the high efficiency refrigeration and evaluates the future scientific research direction in this area. Analysis shows that with the development of hydrostatic thrust bearing to the high speed, high precision, high efficiency, high stability, high multifunction, and high power, the study of hydrostatic thrust bearing will focus on the optimal design of the oil chamber to produce the least amount of heat, how to control the thermal deformation of hydrostatic thrust bearing, and the high efficiency refrigeration to ensure the machining accuracy of CNC equipment.

  11. A study of the transient performance of hydrostatic journal bearings. I - Test apparatus and facility

    Science.gov (United States)

    Scharrer, J. K.; Tellier, J.; Hibbs, R.

    1992-10-01

    A test apparatus was developed for studies of the transient performance of hydrostatic journal bearings operating in liquid nitrogen. The data obtained give the number of revolutions of the shaft contact before the liftoff and after touchdown as a function of bearing/shaft material combinations and operating conditions.

  12. Several particular aspects of hydrostatic shaft guide bearings in mechanical liquid sodium pumps

    International Nuclear Information System (INIS)

    Elie, X.

    A number of problems arise with immersed hydrostatic shaft guide bearings in sodium pumps, mainly at high-temperature operation. Experience has shown that a substantial bearing clearance is required which, in present designs, takes a considerable amount of fluid from the pumps. A new design is suggested, resulting in a very appreciable reduction in the additional flow requirement, while maintaining a comparable load capacity by a hydrodynamic effect

  13. 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.

  14. A study of the transient performance of annular hydrostatic journal bearings in liquid oxygen

    Science.gov (United States)

    Scharrer, J. K.; Tellier, J. G.; Hibbs, R. I.

    1992-07-01

    A test apparatus was used to simulate a cryogenic turbopump start transient in order to determine the liftoff and touchdown speed and amount of wear of an annular hydrostatic bearing in liquid oxygen. The bearing was made of sterling silver and the journal made of Inconel 718. The target application of this configuration is the pump end bearing of the Space Shuttle Main Engine High Pressure Liquid Oxygen Turbopump. Sixty-one transient cycles were performed in liquid oxygen with an additional three tests in liquid nitrogen to certify the test facility and configuration. The bearing showed no appreciable wear during the testing, and the results indicate that the performance of the bearing was not significantly degraded during the testing.

  15. Calculation of hydrostatic radial bearing for main circulating pump of 500 BIKS type

    International Nuclear Information System (INIS)

    Hnatek, T.; Sojka, P.

    1978-01-01

    Computer calculations of the radial hydrostatic bearing were performed for the main circulating pump of the 500 BIKS type designed for WWER reactors. The calculations were based on the Reynolds equation of thin layer hydrodynamic pressure in turbulent flow. Relations were derived for orifice reducer flow. In contrast to previous calculations conducted for laminar flow, the results are more accurate because the nature of bearing lubrication evidently is turbulent. The required loading of 21,700 N in normal pump operation is fully compensated at a full eccentricity of 0.77. Operating tests of the pump also confirmed that the actual radial forces on the rotor did not attain the desired loading. On the other hand, thanks to the bearing brass design, the bearing is capable of short-time operation with limit eccentricity, ie., at start, in deceleration and in emergency conditions. (Z.M.)

  16. Performance optimization of grooved slippers for aero hydraulic pumps

    Directory of Open Access Journals (Sweden)

    Juan Chen

    2016-06-01

    Full Text Available A computational fluid dynamics (CFD simulation method based on 3-D Navier–Stokes equation and Arbitrary Lagrangian–Eulerian (ALE method is presented to analyze the grooved slipper performance of piston pump. The moving domain of grooved slipper is transformed into a fixed reference domain by the ALE method, which makes it convenient to take the effects of rotate speed, body force, temperature, and oil viscosity into account. A geometric model to express the complex structure, which covers the orifice of piston and slipper, vented groove and the oil film, is constructed. Corresponding to different oil film thicknesses calculated in light of hydrostatic equilibrium theory and boundary conditions, a set of simulations is conducted in COMSOL to analyze the pump characteristics and effects of geometry (groove width and radius, orifice size on these characteristics. Furthermore, the mechanics and hydraulics analyses are employed to validate the CFD model, and there is an excellent agreement between simulation and analytical results. The simulation results show that the sealing land radius, orifice size and groove width all dramatically affect the slipper behavior, and an optimum tradeoff among these factors is conducive to optimizing the pump design.

  17. Dynamic response characteristics evaluation of hydrostatic bearing in hydraulic piston pump/motor

    International Nuclear Information System (INIS)

    Ham, Young Bog; Yun, So Nam; Kim, Dong Soo; Choi, Byoung Oh; Kim, Sung Dong

    2001-01-01

    In swash plate type axial piston hydraulic pump and motor, the piston shoe is periodically pressurized with square function shape by supply pressure load as rotation of cylinder barrel. Therefore the recess pressure ono bottom part of piston shoe is suddenly increase through orifice in the piston shoe. In this study, we simulated that the frequency response of the recess pressure against with change of supply pressure with analysis tool. Also, we evaluate the dynamic response characteristics of overbalanced hydrostatic bearing with change of the orifice diameter

  18. Measurements versus Predictions for a Hybrid (Hydrostatic Plus Hydrodynamic) Thrust Bearing for a Range of Orifice Diameters

    Science.gov (United States)

    2010-05-01

    Type of Lubrication for a Tilting Pad Thrust Bearing ,” ASME Journal of Lubrication Technology, 96 Ser F (1), pp. 22-27. [9] Gregory, R.S., 1974...1986, “Measurements of Maximum Temperature in Tilting - Pad Thrust Bearings ,” Technical Preprints - Presented at the ASLE 41st Annual Meeting. (ASLE...Safar [7] provides a modified Reynolds number analysis on hydrostatic thrust bearing performance parameters including the effects of tilt . Finally, San

  19. 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.

  20. 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.

  1. Numerical Modelling and Analysis of Hydrostatic Thrust Air Bearings for High Loading Capacities and Low Air Consumption

    Science.gov (United States)

    Yu, Yunluo; Pu, Guang; Jiang, Kyle

    2017-12-01

    The paper presents a numerical simulation study on hydrostatic thrust air bearings to assess the load capacity, compressed air consumptions, and the dynamic response. Finite Difference Method (FDM) and Finite Volume Method (FVM) are combined to solve the non-linear Reynolds equation to find the pressure distribution of the air bearing gas film and the total loading capacity of the bearing. The influence of design parameters on air film gap characteristics, including the air film thickness, supplied pressure, depth of the groove and external load, are investigated based on the proposed FDM model. The simulation results show that the thrust air bearings with a groove have a higher load capacity and air consumption than without a groove, and the load capacity and air consumption both increase with the depth of the groove. Bearings without the groove are better damped than those with the grooves, and the stability of thrust bearing decreases when the groove depth increases. The stability of the thrust bearings is also affected by their loading.

  2. Calculation methods for externally pressurised (hydrostatic) journal bearings with capillary restrictor control

    Science.gov (United States)

    1992-09-01

    ESDU 92026 provides a procedure for the design and performance analysis of the bearings with five or more identical equally-spaced rectangular recesses (or pockets) fed by identical capillary restrictors from a constant pressure supply. The method takes account of stiffness and overload capacity requirements and determines the bearing overall size and proportions from the required load, speed and shaft diameter, recommends the clearance and supply pressure, and defines the recess dimensions and capillary restrictor size from the properties of the chosen lubricant. Equations and charts allow prediction of the journal displacement under load, the power loss, the lubricant flow rate, and the bearing and lubricant temperatures. The method applies to laminar flow and guidance is given for assessing the onset of non-laminar flow in the bearing and restrictors. Guidance is also given on the likelihood of bearing-induced instability. The user is assisted by flowcharts in applying the method, and two practical worked examples illustrate the procedure. ESDU 92037 introduces a FORTRAN program that implements the method, and magnetic media are available in ESDUpac A9237.

  3. Impact of the thermal effect on the load-carrying capacity of a slipper pair for an aviation axial-piston pump

    Directory of Open Access Journals (Sweden)

    Hesheng TANG

    2018-02-01

    Full Text Available A thermal hydraulic model based on the lumped parameter method is presented to analyze the load-carrying capacity of a slipper pair in an aviation axial-piston pump under specified operating conditions. Both theoretical and experimental results are presented to demonstrate the validity of the thermal hydraulic model. The results illustrate that the squeezing force and thermal wedge bearing force are the main factors that affect the film thickness and load-carrying capacity. At high oil temperature and high load pressure, the film thickness decreases with increasing clamping force due to a combined action of the squeezing bearing force and the thermal wedge bearing force, but the load-carrying capacity will increase. An increase of the film thickness is proven to be beneficial under high shaft rotational speed but especially dangerous as it strongly increases the ripple amplitude of the film thickness, which leads to decreasing the load-carrying capacity. The structural parameters of the slipper can be optimized to achieve desired performance, such as the slipper radius ratio and orifice length diameter ratio. To satisfy the requirement of the load-carrying capacity, the slipper radius ratio should be selected from 1.4 to 1.8, and the orifice length diameter ratio should be selected from 4 to 5. Keywords: Aviation axial piston pump, Fluid lubrication, Load-carrying capacity, Slipper pair, Thermal effect

  4. Variable load failure mechanism for high-speed load sensing electro-hydrostatic actuator pump of aircraft

    Directory of Open Access Journals (Sweden)

    Cun SHI

    2018-05-01

    Full Text Available This paper presents a novel transient lubrication model for the analysis of the variable load failure mechanism of high-speed pump used in Load Sensing Electro-Hydrostatic Actuator (LS-EHA. Focusing on the slipper/swashplate pair partial abrasion, which is considered as the dominant failure mode in the high-speed condition, slipper dynamic models are established. A forth sliding motion of the slipper on the swashplate surface is presented under the fact that the slipper center of mass will rotate around the center of piston ball when the swashplate angle is dynamically adjusted. Besides, extra inertial tilting moments will be produced for the slipper based on the theorem on translation of force, which will increase rapidly when LS-EHA pump operates under high-speed condition. Then, a dynamic lubricating model coupling with fluid film thickness field, temperature field and pressure field is proposed. The deformation effects caused by thermal deflection and hydrostatic pressure are considered. A numerical simulation model is established to validate the effectiveness and accuracy of the proposed model. Finally, based on the load spectrum of aircraft flight profile, the variable load conditions and the oil film characteristics are analyzed, and series of variable load rules of oil film thickness with variable speed/variable pressure/variable displacement are concluded. Keywords: Coupling lubrication model, Electro-Hydrostatic Actuator (EHA, High-speed pump, Partial abrasion, Slipper pair, Variable load

  5. Comparative Performance of a Non-recessed Hole-entry Hybrid/Hydrostatic Conical Journal Bearing Compensated with Capillary and Orifice Restrictors

    Directory of Open Access Journals (Sweden)

    P.G. Khakse

    2016-06-01

    Full Text Available This research paper deals with the theoretical study of comparison of capillary and orifice compensated non-recess hole-entry hydrostatic/ hybrid conical journal bearing. Modified Reynolds equation governing the flow of lubricant in the clearance space of conical journal and bearing has been solved using FEM, Newton-Raphson method and Gauss elimination method. Spherical coordinate system has been employed to obtain the results. The results have been computed for uniform distribution of holes in the circumferential direction with the range of restrictor design parameter C ̅_s2 = 0.02 - 0.1. The numerically simulated result shows, the use of orifice restrictor is to increase bearing stiffness, threshold speed and maximum pressure compared to capillary restrictor for applied radial load.

  6. Gap flows and pressure fields in sealing and bearing gaps of hydrostatic machines. Final report; Spaltstroemungen und Druckfelder in Dicht- und Lagerfugen hydrostatischer Maschinen. Abschlussbericht

    Energy Technology Data Exchange (ETDEWEB)

    Kleist, A.

    1997-07-01

    The `hydrostatic machines` project was concerned with the examination of sealing and bearing gaps in hydraulic machines with the aim of creating a useful simulation tool for designing these gaps. In order to achieve this difficult target, extensive experimental investigations were carried out. A simulation program for the static calculation of sealing and bearing gaps was developed for the key gap bearing and the valve gap. The third main point of the experimental investigations was the examination of the piston/cylinder gap of a radial piston pump. The simulation was able to be verified from experimental results. (orig./AKF) [Deutsch] Das Projekt `Hydrostatische Maschinen` befasste sich mit der Untersuchung hydrostatischen Dicht- und Lagerfugen in hydraulischen Maschinen mit Ziel, fuer die Auslegung dieser Spalte ein handhabbares Simulationswerkzeug zu schaffen. Um dieses hochgesteckte Ziel zu erreichen, wurden umfangreiche experimentelle Untersuchungen durchgefuehrt. Fuer die Keilspaltlagerung und den Ventilsplat wurde ein Simulationsprogramm fuer die stationaere Berechnung von Dicht- und Lagerfugen entwickelt. Der dritte Schwerpunkt der experimentellen Untersuchungen war die Untersuchung des Kolben-Zylinder-Spaltes einer Radialkolbenpumpe. Die Simulation konnte anhand der experimentellen Ergebnisse verifiziert werden. (orig./AKF)

  7. Comparison Between Predictions and Measurements of Performance Characteristics for an Eight Pocket Hybrid (Combination Hydrostatic and Hydrodynamic) Thrust Bearing

    Science.gov (United States)

    2008-12-03

    STB stainless steel housing. Drive End Thrust Collar Free End Splash Guard Slave Thrust Bearing Face STB Flange Figure 12: Exploded view of slave...Bulk Flow Analysis of Hybrid Thrust Bearing for Process Fluid Applications.” ASME Trans., Journal of Tribology , January, Vol. 122 (1), pp. 170-180...ASME Journal of Tribology , Vol. 123, pp. 768-776 [5] San Andrés, L., (2006), “MEEN 626 Notes 2 Derivation of the Classical Reynolds Equation for

  8. Load of the slipper-swash plate kinematic pair of an axial piston pump

    Directory of Open Access Journals (Sweden)

    Złoto Tadeusz

    2018-01-01

    Full Text Available The paper presents problems related to the twisting moment of the slipper. The load of the slipper and the piston has been presented and the complex formula of twisting moment of the slipper has been established. Achieved results has been presented graphically. The conducted research has indicated that the value of the twisting moment relays on both the exploitation and geometrical parameters.

  9. Research progress of the static and dynamic characteristics and motion errors of hydrostatic supports

    Directory of Open Access Journals (Sweden)

    Zhiwei WANG

    2016-06-01

    Full Text Available At present, the research on static and dynamic characteristics of hydrostatic supports depend on the form and structure of the restrictor, which are mainly focused on the influences of recess shape, bearing structure, bearing surface roughness, lubricant and elastic deformations of the bearing. There are few studies on the thermal effect of hydrostatic supports and static and dynamic characteristics of hydrostatic guideways. The research on motion errors of hydrostatic supports is primarily based on the static equilibrium of the moving part. The effects of the motion speed of the moving part and structural deformation on the motion errors are not considered. Finally, the research prospects from the standardization, modularization and industrialization of hydrostatic supports, thermal effect of hydrostatic bearing, the static and dynamic characteristics of hydrostatic guideways and motion errors of hydrostatic supports under operating conditions are concluded.

  10. Restoring the rare Kentucky lady's slipper orchid to the Kisatchie National Forest

    Science.gov (United States)

    James P. Barnett; Kevin Allen; David Moore

    2012-01-01

    The Kentucky lady’s slipper (Cypripedium kentuckiense C.F. Reed [Orchidaceae]) is a spectacular orchid native to the southeastern US. Although its range includes much of the Southeast, it is rare due to loss of appropriate edaphic and climatic habitats. Efforts to restore this species to the Kisatchie National Forest in Louisiana were initiated by a high school student...

  11. Bearing structures

    International Nuclear Information System (INIS)

    Lee, A.S.; Preece, G.E.

    1988-01-01

    A hydrostatic bearing for the lower end of the vertical shaft of a sodium pump comprises a support shell encircling the shaft and a bush located between the shell and shaft. Liquid sodium is fed from the pump outlet to the bush/shaft and bush/shell interfaces to provide hydrostatic support. The bush outer surface and the shell inner surface are of complementary part-spherical shape and the bush floats relative to the shaft so that the bush can align itself with the shaft axis. Monitoring of the relative rotational speed of the bush with respect to the shaft (such rotation being induced by the viscous drag forces present) is also performed for the purposes of detecting abnormal operation of the bearing or partial seizure, at least one magnet is rotatable with the bush, and a magnetic sensor provides an output having a frequency related to the speed of the bush. (author)

  12. Comparison of Designed Slippers Splints with the Splints Available on the Market in the Treatment of Hallux Valgus

    Directory of Open Access Journals (Sweden)

    Yadollah Pournia

    2012-02-01

    Full Text Available Hallux valgus or the lateral deviation of the great toe is a complex disease. If it is not treated, it will cause the deviation of other toes. Hallux valgus is three times more common in females and may cause uncomfortable deformity of the foot, problems in putting on unsuitable and narrow toe box shoes, and pain on the medial side of the first metatarsophalangeal joint; therefore, patients seek medical services. Untreated hallux valgus may cause the hammer toe deformity of the second toe. In this cohort study, 30 patients referring to the Orthopedic Clinic of Shohada Ashayer Hospital of Khorramabad, Iran, with a complaint of hallux valgus were randomly divided into two groups. The splints designed by the researches (slippers splints were given to the case group, and the splints on the market including night splints and interdigital pads were given to the control group. The patients were followed every three months for a year and every time the weight bearing anteroposterior radiography of both feet were taken and hallux valgus and inter-metatarsal angles were measured. The data was analyzed by the SPSS software using repeated measure tests. In the case group that used the designed splints regularly, hallux valgus angles decreased more dramatically than in the control group (P<0.001. This study showed that, despite controversies over the nonoperative treatment of hallux valgus, if hallux valgus angle in patient is mild to moderate, the splint can be used as a nonoperative treatment.

  13. Boots of Leather, Slippers of Gold: The History of a Lesbian Community

    Directory of Open Access Journals (Sweden)

    Maria Chiara Ferro

    2016-03-01

    Full Text Available Elizabeth Lapovsky Kennedy, Madeline D. Davis, Boots of Leather, Slippers of Gold: The History of a Lesbian Community (1993. New York: Routledge, 2014.   La recensione sottolinea la rilevanza del volume Boots of Leather, Slippers of Gold a vent’anni dalla pubblicazione, sia perché raccoglie e preserva testimonianze di butches e femmes degli anni ’40 e ’50, sia perché chiarisce il ruolo sociale della comunità butch-femme in quanto sede di resistenza pre-politica. Inoltre, si evidenzia l’utilità di modelli interpretativi informati dagli studi queer e transgender nell’ambito della ricerca storica su identità non normative come quelle butch e femme.

  14. Phylogenetic relationships, character evolution, and taxonomic implications within the slipper lobsters (Crustacea: Decapoda: Scyllaridae).

    Science.gov (United States)

    Yang, Chien-Hui; Bracken-Grissom, Heather; Kim, Dohyup; Crandall, Keith A; Chan, Tin-Yam

    2012-01-01

    The slipper lobsters belong to the family Scyllaridae which contains a total of 20 genera and 89 species distributed across four subfamilies (Arctidinae, Ibacinae, Scyllarinae, and Theninae). We have collected nucleotide sequence data from regions of five different genes (16S, 18S, COI, 28S, H3) to estimate phylogenetic relationships among 54 species from the Scyllaridae with a focus on the species rich subfamily Scyllarinae. We have included in our analyses at least one representative from all 20 genera in the Scyllaridae and 35 of the 52 species within the Scyllarinae. Our resulting phylogenetic estimate shows the subfamilies are monophyletic, except for Ibacinae, which has paraphyletic relationships among genera. Many of the genera within the Scyllarinae form non-monophyletic groups, while the genera from all other subfamilies form well supported clades. We discuss the implications of this history on the evolution of morphological characters and ecological transitions (nearshore vs. offshore) within the slipper lobsters. Finally, we identify, through ancestral state character reconstructions, key morphological features diagnostic of the major clades of diversity within the Scyllaridae and relate this character evolution to current taxonomy and classification. Copyright © 2011 Elsevier Inc. All rights reserved.

  15. Increasing populations of Kentucky lady’s slipper orchid on the Kisatchie National Forest: seedling production and outplanting trials

    Science.gov (United States)

    James Barnett; Shannan Sharp; Kevin Allen; Andy Scott

    2013-01-01

    The Kentucky lady’s slipper orchid (Cypripedium kentuckiense C.F. Reed) is a tall, stately perennial plant with the largest flowers of any Cypripedium known. Its range includes much of the Southeastern United States, though it is rare throughout its range due to specific edaphic and climatic habitat requirements. In Louisiana, a...

  16. The Hydrostatic Paradox.

    Science.gov (United States)

    Wilson, Alpha E.

    1995-01-01

    Presents an example demonstrating the quantitative resolution of the hydrostatic paradox which is the realization that the force due to fluid pressure on the bottom of a vessel can be considerably greater or considerably less than the weight of the fluid in the vessel. (JRH)

  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. Hybrid bearings for LH2 and LO2 turbopumps

    Science.gov (United States)

    Butner, M. F.; Lee, F. C.

    1985-01-01

    Hybrid combinations of hydrostatic and ball bearings can improve bearing performance for liquid hydrogen and liquid oxygen turbopumps. Analytic studies were conducted to optimize hybrid bearing designs for the SSME-type turbopump conditions. A method to empirically determine damping coefficients was devised. Four hybrid bearing configurations were designed, and three were fabricated. Six hybrid and hydrostatic-only bearing configurations will be tested for steady-state and transient performance, and quantification of damping coefficients. The initial tests were conducted with the liquid hydrogen bearing.

  19. Performance of gas-lubricated cruciform-mounted tilting-pad journal bearings and a damped flexibly mounted spiral-groove thrust bearing

    Science.gov (United States)

    Ream, L. W.

    1974-01-01

    A test program was conducted to determine the performance characteristics of gas-lubricated cruciform-mounted tilting-pad journal bearings and a damped spiral-groove thrust bearing designed for the Brayton cycle rotating unit (BRU). Hydrostatic, hybrid (simultaneously hydrostatic and hydrodynamic), and hydrodynamic tests were conducted in argon gas at ambient pressure and temperature ranges representative of operation to the 10.5 kWe BRU power-generating level. Performance of the gas lubricated bearings is presented including hydrostatic gas flow rates, bearing clearances, bearing temperatures, and transient performance.

  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. 46 CFR 64.83 - Hydrostatic test.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 2 2010-10-01 2010-10-01 false Hydrostatic test. 64.83 Section 64.83 Shipping COAST... HANDLING SYSTEMS Periodic Inspections and Tests of MPTs § 64.83 Hydrostatic test. (a) The hydrostatic test..., the heating coil passing a hydrostatic test at a pressure of 200 psig or more or 50 percent or more...

  2. Dynamic distribution patterns of ribosomal DNA and chromosomal evolution in Paphiopedilum, a lady's slipper orchid

    Directory of Open Access Journals (Sweden)

    Albert Victor A

    2011-09-01

    Full Text Available Abstract Background Paphiopedilum is a horticulturally and ecologically important genus of ca. 80 species of lady's slipper orchids native to Southeast Asia. These plants have long been of interest regarding their chromosomal evolution, which involves a progressive aneuploid series based on either fission or fusion of centromeres. Chromosome number is positively correlated with genome size, so rearrangement processes must include either insertion or deletion of DNA segments. We have conducted Fluorescence In Situ Hybridization (FISH studies using 5S and 25S ribosomal DNA (rDNA probes to survey for rearrangements, duplications, and phylogenetically-correlated variation within Paphiopedilum. We further studied sequence variation of the non-transcribed spacers of 5S rDNA (5S-NTS to examine their complex duplication history, including the possibility that concerted evolutionary forces may homogenize diversity. Results 5S and 25S rDNA loci among Paphiopedilum species, representing all key phylogenetic lineages, exhibit a considerable diversity that correlates well with recognized evolutionary groups. 25S rDNA signals range from 2 (representing 1 locus to 9, the latter representing hemizygosity. 5S loci display extensive structural variation, and show from 2 specific signals to many, both major and minor and highly dispersed. The dispersed signals mainly occur at centromeric and subtelomeric positions, which are hotspots for chromosomal breakpoints. Phylogenetic analysis of cloned 5S rDNA non-transcribed spacer (5S-NTS sequences showed evidence for both ancient and recent post-speciation duplication events, as well as interlocus and intralocus diversity. Conclusions Paphiopedilum species display many chromosomal rearrangements - for example, duplications, translocations, and inversions - but only weak concerted evolutionary forces among highly duplicated 5S arrays, which suggests that double-strand break repair processes are dynamic and ongoing. These

  3. Accurate tool height control by bearing gap adjustment

    NARCIS (Netherlands)

    Wielen, van der A.M.; Schellekens, P.H.J.; Jaartsveld, F.T.M.

    2002-01-01

    Face turning of optical surfaces on precision lathes needs high precision tool height adjustment, which may be a difficult and time-consuming task. In this paper we present a new tool adjustment mechanism based on varying the bearing gap height of the hydrostatic bearings present in precision lathe

  4. Metal extrusion using hydrostatic pressures

    International Nuclear Information System (INIS)

    Sauve, Ch.

    1965-01-01

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

  5. Bearing system

    Science.gov (United States)

    Kapich, Davorin D.

    1987-01-01

    A bearing system includes backup bearings for supporting a rotating shaft upon failure of primary bearings. In the preferred embodiment, the backup bearings are rolling element bearings having their rolling elements disposed out of contact with their associated respective inner races during normal functioning of the primary bearings. Displacement detection sensors are provided for detecting displacement of the shaft upon failure of the primary bearings. Upon detection of the failure of the primary bearings, the rolling elements and inner races of the backup bearings are brought into mutual contact by axial displacement of the shaft.

  6. Thermohydrodynamic analysis of cryogenic liquid turbulent flow fluid film bearings

    Science.gov (United States)

    Andres, Luis San

    1993-01-01

    A thermohydrodynamic analysis is presented and a computer code developed for prediction of the static and dynamic force response of hydrostatic journal bearings (HJB's), annular seals or damper bearing seals, and fixed arc pad bearings for cryogenic liquid applications. The study includes the most important flow characteristics found in cryogenic fluid film bearings such as flow turbulence, fluid inertia, liquid compressibility and thermal effects. The analysis and computational model devised allow the determination of the flow field in cryogenic fluid film bearings along with the dynamic force coefficients for rotor-bearing stability analysis.

  7. ANSYS Modeling of Hydrostatic Stress Effects

    Science.gov (United States)

    Allen, Phillip A.

    1999-01-01

    Classical metal plasticity theory assumes that hydrostatic pressure has no effect on the yield and postyield behavior of metals. Plasticity textbooks, from the earliest to the most modem, infer that there is no hydrostatic effect on the yielding of metals, and even modem finite element programs direct the user to assume the same. The object of this study is to use the von Mises and Drucker-Prager failure theory constitutive models in the finite element program ANSYS to see how well they model conditions of varying hydrostatic pressure. Data is presented for notched round bar (NRB) and "L" shaped tensile specimens. Similar results from finite element models in ABAQUS are shown for comparison. It is shown that when dealing with geometries having a high hydrostatic stress influence, constitutive models that have a functional dependence on hydrostatic stress are more accurate in predicting material behavior than those that are independent of hydrostatic stress.

  8. Mechanical response of collagen molecule under hydrostatic compression

    International Nuclear Information System (INIS)

    Saini, Karanvir; Kumar, Navin

    2015-01-01

    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.

  9. Mechanical response of collagen molecule under hydrostatic compression.

    Science.gov (United States)

    Saini, Karanvir; 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. Copyright © 2015 Elsevier B.V. All rights

  10. 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.

  11. Real-time controller for hydrostatic transmission

    OpenAIRE

    2014-01-01

    M. Ing. (Electrical and Electronic Engineering) This dissertation describes the development of a modular real-time controller implemented on a personal computer for a hydrostatically driven vehicle. In such a vehicle the conventional mechanical transmission is replaced with a hydrostatic pump and two hydrostatic motors, making use of the secondary control principle. The infinitely variable transmission and wheel pair controller gives the vehicle superior traction and mobility over conventi...

  12. A hybrid hydrostatic and non-hydrostatic numerical model for shallow flow simulations

    Science.gov (United States)

    Zhang, Jingxin; Liang, Dongfang; Liu, Hua

    2018-05-01

    Hydrodynamics of geophysical flows in oceanic shelves, estuaries, and rivers, are often studied by solving shallow water model equations. Although hydrostatic models are accurate and cost efficient for many natural flows, there are situations where the hydrostatic assumption is invalid, whereby a fully hydrodynamic model is necessary to increase simulation accuracy. There is a growing concern about the decrease of the computational cost of non-hydrostatic pressure models to improve the range of their applications in large-scale flows with complex geometries. This study describes a hybrid hydrostatic and non-hydrostatic model to increase the efficiency of simulating shallow water flows. The basic numerical model is a three-dimensional hydrostatic model solved by the finite volume method (FVM) applied to unstructured grids. Herein, a second-order total variation diminishing (TVD) scheme is adopted. Using a predictor-corrector method to calculate the non-hydrostatic pressure, we extended the hydrostatic model to a fully hydrodynamic model. By localising the computational domain in the corrector step for non-hydrostatic pressure calculations, a hybrid model was developed. There was no prior special treatment on mode switching, and the developed numerical codes were highly efficient and robust. The hybrid model is applicable to the simulation of shallow flows when non-hydrostatic pressure is predominant only in the local domain. Beyond the non-hydrostatic domain, the hydrostatic model is still accurate. The applicability of the hybrid method was validated using several study cases.

  13. Towards a Supertree of Arthropoda: A Species-Level Supertree of the Spiny, Slipper and Coral Lobsters (Decapoda: Achelata).

    Science.gov (United States)

    Davis, Katie E; Hesketh, Thomas W; Delmer, Cyrille; Wills, Matthew A

    2015-01-01

    While supertrees have been built for many vertebrate groups (notably birds, mammals and dinosaurs), invertebrates have attracted relatively little attention. The paucity of supertrees of arthropods is particularly surprising given their economic and ecological importance, as well as their overwhelming contribution to biodiversity. The absence of comprehensive archives of machine-readable source trees, coupled with the need for software implementing repeatable protocols for managing them, has undoubtedly impeded progress. Here we present a supertree of Achelata (spiny, slipper and coral lobsters) as a proof of concept, constructed using new supertree specific software (the Supertree Toolkit; STK) and following a published protocol. We also introduce a new resource for archiving and managing published source trees. Our supertree of Achelata is synthesised from morphological and molecular source trees, and represents the most complete species-level tree of the group to date. Our findings are consistent with recent taxonomic treatments, confirming the validity of just two families: Palinuridae and Scyllaridae; Synaxidae were resolved within Palinuridae. Monophyletic Silentes and Stridentes lineages are recovered within Palinuridae, and all sub-families within Scyllaridae are found to be monophyletic with the exception of Ibacinae. We demonstrate the feasibility of building larger supertrees of arthropods, with the ultimate objective of building a complete species-level phylogeny for the entire phylum using a divide and conquer strategy.

  14. Towards a Supertree of Arthropoda: A Species-Level Supertree of the Spiny, Slipper and Coral Lobsters (Decapoda: Achelata.

    Directory of Open Access Journals (Sweden)

    Katie E Davis

    Full Text Available While supertrees have been built for many vertebrate groups (notably birds, mammals and dinosaurs, invertebrates have attracted relatively little attention. The paucity of supertrees of arthropods is particularly surprising given their economic and ecological importance, as well as their overwhelming contribution to biodiversity. The absence of comprehensive archives of machine-readable source trees, coupled with the need for software implementing repeatable protocols for managing them, has undoubtedly impeded progress. Here we present a supertree of Achelata (spiny, slipper and coral lobsters as a proof of concept, constructed using new supertree specific software (the Supertree Toolkit; STK and following a published protocol. We also introduce a new resource for archiving and managing published source trees. Our supertree of Achelata is synthesised from morphological and molecular source trees, and represents the most complete species-level tree of the group to date. Our findings are consistent with recent taxonomic treatments, confirming the validity of just two families: Palinuridae and Scyllaridae; Synaxidae were resolved within Palinuridae. Monophyletic Silentes and Stridentes lineages are recovered within Palinuridae, and all sub-families within Scyllaridae are found to be monophyletic with the exception of Ibacinae. We demonstrate the feasibility of building larger supertrees of arthropods, with the ultimate objective of building a complete species-level phylogeny for the entire phylum using a divide and conquer strategy.

  15. 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

  16. 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

  17. 49 CFR 230.36 - Hydrostatic testing of boilers.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Hydrostatic testing of boilers. 230.36 Section 230... Appurtenances Pressure Testing of Boilers § 230.36 Hydrostatic testing of boilers. (a) Time of test. The... to any hydrostatic pressure. Hydrostatic testing required by these rules shall be conducted at 25...

  18. 49 CFR 178.814 - Hydrostatic pressure test.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 2 2010-10-01 2010-10-01 false Hydrostatic pressure test. 178.814 Section 178.814... Testing of IBCs § 178.814 Hydrostatic pressure test. (a) General. The hydrostatic pressure test must be... preparation for the hydrostatic pressure test. For metal IBCs, the test must be carried out before the fitting...

  19. Control of superplastic cavitation by hydrostatic pressure

    International Nuclear Information System (INIS)

    Bampton, C.C.; Ghosh, A.K.; Hamilton, C.H.; Mahoney, M.W.; Raj, R.

    1983-01-01

    It has been shown that the application of hydrostatic gas pressures during superplastic deformation of fine grained 7475 Al can prevent the intergranular cavitation normally encountered at atmospheric pressure. A critical ratio of hydrostatic pressure to flow stress may be defined for each superplastic forming condition above which virtually no cavitation occurs. In deformation conditions where intergranular cavitation plays a significant part in final tensile rupture, superplastic ductility may be improved by the application of hydrostatic pressures. Similarly, detrimental effects of large superplastic strains on service properties may be reduced or eliminated by the application of suitable hydrostatic pressures during superplastic forming. In this case, superplastically formed material may have the same design allowables as conventional 7475 Al sheet

  20. Helium behaviour in aluminium under hydrostatic pressure

    International Nuclear Information System (INIS)

    Sokurskij, Yu.N.; Tebus, V.N.; Zudilin, V.A.; Tumanova, G.M.

    1989-01-01

    Effect of hydrostatic compression on equilibrium helium bubbles in low aluminium-lithium alloy irradiated in reactor at 570 K is investigated. Measurements of hydrostatic density and electron-microscopic investigations have shown, that application of up to 2 GPa pressure reduces equilibrium size of helium bubbles and reduces helium swelling. Kinetics and thermodynamics of the process are considered with application of 'rigid sphere' equation which describes helium state in bubbles

  1. Journal bearing

    Science.gov (United States)

    Menke, John R.; Boeker, Gilbert F.

    1976-05-11

    1. An improved journal bearing comprising in combination a non-rotatable cylindrical bearing member having a first bearing surface, a rotatable cylindrical bearing member having a confronting second bearing surface having a plurality of bearing elements, a source of lubricant adjacent said bearing elements for supplying lubricant thereto, each bearing element consisting of a pair of elongated relatively shallowly depressed surfaces lying in a cylindrical surface co-axial with the non-depressed surface and diverging from one another in the direction of rotation and obliquely arranged with respect to the axis of rotation of said rotatable member to cause a flow of lubricant longitudinally along said depressed surfaces from their distal ends toward their proximal ends as said bearing members are rotated relative to one another, each depressed surface subtending a radial angle of less than 360.degree., and means for rotating said rotatable bearing member to cause the lubricant to flow across and along said depressed surfaces, the flow of lubricant being impeded by the non-depressed portions of said second bearing surface to cause an increase in the lubricant pressure.

  2. Hydrostatic Stress Effects in Metal Plasticity

    Science.gov (United States)

    Wilson, Christopher D.

    1999-01-01

    Since the 1940s, the theory of plasticity has assumed that hydrostatic stress does not affect the yield or postyield behavior of metals. This assumption is based on the early work of Bridgman. Bridgman found that hydrostatic pressure (compressive stress) does not affect yield behavior until a substantial amount of pressure (greater than 100 ksi) is present. The objective of this study was to determine the effect of hydrostatic tension on yield behavior. Two different specimen geometries were examined: an equal-arm bend specimen and a double edge notch specimen. The presence of a notch is sufficient to develop high enough hydrostatic tensile stresses to affect yield. The von Mises yield function, which does not have a hydrostatic component, and the Drucker-Prager yield function, which includes a hydrostatic component, were used in finite element analyses of the two specimen geometries. The analyses were compared to test data from IN 100 specimens. For both geometries, the analyses using the Drucker-Prager yield function more closely simulated the test data. The von Mises yield function lead to 5-10% overprediction of the force-displacement or force-strain response of the test specimens.

  3. Intraoperative hydrostatic reduction of intussusception

    Directory of Open Access Journals (Sweden)

    Chatterjee Uday

    2008-01-01

    Full Text Available Aims: To find out an easier way of reduction of intussusception during open surgery to avoid unnecessary bowel injury. Materials and Methods: Under general anesthesia, before laparotomy, warm normal saline was infused into the rectum with a Foley catheter and an intravenous drip set maintaining the level of the bottle at 80 cm above the operating table. After opening the abdomen, pressure was applied on the colon filled with normal saline distal to the intussusceptum. The pressure was transmitted to the intussusceptum and the walls of the intussuscipient and caused reduction of intussusception without any injury to the intussuscipient and intussusceptum. This procedure was performed on those patients on whom laparotomy was performed as a primary procedure due to nonavailability of fluoroscopy or ultrasonography. Results: Between August 1998 and July 2005, we had six patients of mean (range age 11 months (7-17 months. In two cases, at laparotomy, the intussusceptions were found to have already reduced. Conclusions: Gentle finger pressure is necessary for reduction of intussusception. This subjective "gentleness" is dependant on experience of the surgeon and varies from person to person. Focal pressure on the intussuscipient and apex of the intussusceptum by the finger during reduction may be more damaging than the diffusely transmitted hydrostatic pressure even by a less-experienced surgeon. This will avoid the needless resection and anastomosis of the intestine on many occasions.

  4. On the Design of Tilting-Pad Thrust Bearings

    OpenAIRE

    Heinrichson, Niels; Santos, Ilmar

    2007-01-01

    Pockets are often machined in the surfaces of tilting-pad thrust bearings to allow for hydrostatic jacking in the start-up phase. Pockets and other recesses in the surfaces of bearing pads influence the pressure distribution and thereby the position of the pivot resulting in the most advantageous pad convergence ratio. In this thesis, a theoretical approach is applied in the attempt to quantify the influence of recesses in the pad surfaces. The recesses may be relatively deep and enclosed as ...

  5. Survey of Damage Investigation of Babbitted Industrial Bearings

    Directory of Open Access Journals (Sweden)

    Lyle A. Branagan

    2015-04-01

    Full Text Available This survey collects the efforts to understand the sources and consequences of damage to babbitted industrial bearings, which operate by means of a hydrodynamic, or hydrostatic, film. Major individual damage types are discussed in the context of major damage categories.

  6. GAS BEARING

    Science.gov (United States)

    Skarstrom, C.W.

    1960-09-01

    A gas lubricated bearing for a rotating shaft is described. The assembly comprises a stationary collar having an annular member resiliently supported thereon. The collar and annular member are provided with cooperating gas passages arranged for admission of pressurized gas which supports and lubricates a bearing block fixed to the rotatable shaft. The resilient means for the annular member support the latter against movement away from the bearing block when the assembly is in operation.

  7. Grizzly bear

    Science.gov (United States)

    Schwartz, C.C.; Miller, S.D.; Haroldson, M.A.; Feldhamer, G.; Thompson, B.; Chapman, J.

    2003-01-01

    The grizzly bear inspires fear, awe, and respect in humans to a degree unmatched by any other North American wild mammal. Like other bear species, it can inflict serious injury and death on humans and sometimes does. Unlike the polar bear (Ursus maritimus) of the sparsely inhabited northern arctic, however, grizzly bears still live in areas visited by crowds of people, where presence of the grizzly remains physically real and emotionally dominant. A hike in the wilderness that includes grizzly bears is different from a stroll in a forest from which grizzly bears have been purged; nighttime conversations around the campfire and dreams in the tent reflect the presence of the great bear. Contributing to the aura of the grizzly bear is the mixture of myth and reality about its ferocity. unpredictable disposition, large size, strength, huge canines, long claws, keen senses, swiftness, and playfulness. They share characteristics with humans such as generalist life history strategies. extended periods of maternal care, and omnivorous diets. These factors capture the human imagination in ways distinct from other North American mammals. Precontact Native American legends reflected the same fascination with the grizzly bear as modern stories and legends (Rockwell 1991).

  8. Effects of hydrostatic pressure on mouse sperm.

    Science.gov (United States)

    Karimi, N; Kamangar, P Bahrami; Azadbakht, M; Amini, A; Amiri, I

    2014-01-01

    The objective of this study was to investigate the abnormalities in sperm after exposure to hydrostatic pressure. Hydrostatic pressure acting on the cells is one of the fundamental environmental mechanical forces. Disorders of relationship between the cells and this mechanical force, such as when pressure varies beyond physiological limits, can lead to disease or pathological states. Sperm exposed to different range of hydrostatic pressure within male reproductive system and after entering the female reproductive system. Sexually mature male NMRI mice, 8-12 weeks-old were sperm donors. Sperms were separated from the caudal epididymis and maintained in Ham's F-10 culture medium supplemented with 10 % FBS and divided into control and treatments. Sperm suspensions in the treatments were placed within pressure chamber and were subjected to increased hydrostatic pressure of 25, 50 and 100 mmHg (treatment I, II and III) above atmospheric pressure for 2 and 4 h. Sperm viability, motility, morphology, DNA integrity and fertilizing ability were assessed and compared with control. Results showed that hydrostatic pressure dependent on ranges and time manner reduced sperm quality due to adverse effect on viability, motility , morphology, DNA integrity and fertilizing ability in all of treatments, especially after 4h (phydrostatic pressure reduces sperm quality as a consequence of adverse effects on sperm parameters and may cause male infertility or subfertility (Tab. 5, Ref. 5).

  9. On the Design of Tilting-Pad Thrust Bearings

    DEFF Research Database (Denmark)

    Heinrichson, Niels

    2007-01-01

    Pockets are often machined in the surfaces of tilting-pad thrust bearings to allow for hydrostatic jacking in the start-up phase. Pockets and other recesses in the surfaces of bearing pads influence the pressure distribution and thereby the position of the pivot resulting in the most advantageous...... based on the Reynolds equation are used. They include the effects of variations of viscosity with temperature and the deformation of the bearing pads due to pressure and thermal gradients. The models are validated using measurements. Tilting-pad bearings of standard design are studied and the influences...... of the friction loss. Both this bearing and the bearing design with enclosed recesses in the high-pressure regions of the pads suffer from a higher sensitivity to the position of the pivot. The design of such bearing is therefore no trivial task....

  10. Numerical analysis of capillary compensated micropolar fluid lubricated hole-entry journal bearings

    Directory of Open Access Journals (Sweden)

    Nathi Ram

    2016-06-01

    Full Text Available The micropolar lubricated symmetric/asymmetric hole-entry bearings using capillary restrictor have been analyzed in the present work. Reynolds equation for micropolar lubricant has been derived and solved by FEM. The results have been computed using selected parameters of micropolar lubricant for hole-entry hydrostatic/hybrid journal bearings. A significant increase in damping and stiffness coefficients is observed for bearings having micropolar parameter N2=0.9, lm=10 than similar bearings under Newtonian lubricant. The threshold speed gets increased when symmetric bearing lubricated under micropolar fluid than Newtonian lubricant. The threshold speed gets increased when symmetric bearing lubricated under micropolar fluid than Newtonian lubricant.

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

    International Nuclear Information System (INIS)

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

    2014-01-01

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

  12. Analysis of the cylinder block tilting inertia moment and its effect on the performance of high-speed electro-hydrostatic actuator pumps of aircraft

    Directory of Open Access Journals (Sweden)

    Junhui ZHANG

    2018-01-01

    Full Text Available Electro-hydrostatic actuator (EHA pumps are usually characterized as high speed and small displacement. The tilting inertia moment on the cylinder block produced by the inertia forces of piston/slipper assemblies cannot be ignored when analyzing the cylinder block balance. A large tilting inertia moment will make the cylinder block tilt away from the valve plate, resulting in severe wear and significantly increased leakage. This paper presents an analytical expression for the tilting inertia moment on the cylinder block by means of vector analysis. In addition, a high-speed test rig was built up, and experiments on an EHA pump prototype were carried out at high speeds of up to 10,000 r/min. The predicted nature of the cylinder block tilt at high speeds corresponds closely to the witness marks on the dismantled EHA pump prototype. It is suggested that more attention should be given to the tilting inertia moment acting on the cylinder block of an EHA pump since both wear and leakage flow between the cylinder block and the valve plate are very much dependent on this tilting moment.

  13. 46 CFR 154.562 - Cargo hose: Hydrostatic test.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 5 2010-10-01 2010-10-01 false Cargo hose: Hydrostatic test. 154.562 Section 154.562 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) CERTAIN BULK DANGEROUS CARGOES SAFETY... Hose § 154.562 Cargo hose: Hydrostatic test. Each cargo hose must pass a hydrostatic pressure test at...

  14. 46 CFR 61.30-10 - Hydrostatic test.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 2 2010-10-01 2010-10-01 false Hydrostatic test. 61.30-10 Section 61.30-10 Shipping... 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...

  15. 49 CFR 178.605 - Hydrostatic pressure test.

    Science.gov (United States)

    2010-10-01

    ... 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. The hydrostatic pressure test must be conducted for the qualification of all metal, plastic, and composite...

  16. Railcar waste transfer system hydrostatic test

    International Nuclear Information System (INIS)

    Ellingson, S.D.

    1997-01-01

    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

  17. Railcar waste transfer system hydrostatic test report

    International Nuclear Information System (INIS)

    Ellingson, S.D.

    1997-01-01

    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

  18. Hydrodynamic modelling of hydrostatic magnesium extrusion

    NARCIS (Netherlands)

    Moodij, Ellen; de Rooij, Matthias B.; Schipper, Dirk 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

  19. Hydrostatic Paradox: Experimental Verification of Pressure Equilibrium

    Science.gov (United States)

    Kodejška, C.; Ganci, S.; Ríha, J.; Sedlácková, H.

    2017-01-01

    This work is focused on the experimental verification of the balance between the atmospheric pressure acting on the sheet of paper, which encloses the cylinder completely or partially filled with water from below, where the hydrostatic pressure of the water column acts against the atmospheric pressure. First of all this paper solves a theoretical…

  20. Mechanical design problems associated with turbopump fluid film bearings

    Science.gov (United States)

    Evces, Charles R.

    1990-01-01

    Most high speed cryogenic turbopumps for liquid propulsion rocket engines currently use ball or roller contact bearings for rotor support. The operating speeds, loads, clearances, and environments of these pumps combine to make bearing wear a limiting factor on turbopump life. An example is the high pressure oxygen turbopump (HPOTP) used in the Space Shuttle Main Engine (SSME). Although the HPOTP design life is 27,000 seconds at 30,000 rpms, or approximately 50 missions, bearings must currently be replaced after 2 missions. One solution to the bearing wear problem in the HPOTP, as well as in future turbopump designs, is the utilization of fluid film bearings in lieu of continuous contact bearings. Hydrostatic, hydrodynamic, and damping seal bearings are all replacement candidates for contact bearings in rocket engine high speed turbomachinery. These three types of fluid film bearings have different operating characteristics, but they share a common set of mechanical design opportunities and difficulties. Results of research to define some of the mechanical design issues are given. Problems considered include transient strat/stop rub, non-operational rotor support, bearing wear inspection and measurement, and bearing fluid supply route. Emphasis is given to the HPOTP preburner pump (PBP) bearing, but the results are pertinent to high-speed cryogenic turbomachinery in general.

  1. Dynamic behavior of hybrid sodium bearings. Theoretical and experimental studies

    International Nuclear Information System (INIS)

    Guidez, J.; Juignet, N.; Queval, M.

    1981-08-01

    The primary sodium pump shaft lower section of a fast breeder reactor is guided by a hydrostatic sodium bearing. This recess type bearing is supplied via orifices restrictors. Sodium is sampled at hight pressure at the diffuser outlet and is then centrifuged towards the orifices restrictors. Bearing stiffness and damping data is essential for the study of rotor dynamic behavior. Two points in particular may then be studied: - calculation of rotor instability ranges and critical speeds, - dynamic behavior of the rotor in the event of an earthquake. As regards the bearing design, the problem is to obtain the pressure fields in the liquid film. The integration of these pressure fields will then give the stiffness coefficients. The damping coefficients can then be obtained by the same calculation after slight displacement. The Reynolds equation can be used to study the liquid film (under any conditions for the turbulent and inertia effects). Then the computer code DELPAL is explained that solves the modified Reynolds equation using a finite element method. The presentation of tests conducted in 1981 on the Super-Phenix 1 full scall bearing (diameter 850 mm) in water is made. In conclusion this paper describes a method for calculating the stiffness and damping matrices of a hydrostatic bearing using the DELPAL calculation code and shows the loop of behavior tests on a bearing with sinusoidal excitation. The results, obtained by calculation and by testing, are indispensable when calculating the dynamic behavior of the shaft line

  2. Seismic evaluation of a large nuclear pump bearing using non-linear dynamic analysis

    International Nuclear Information System (INIS)

    Huber, K.A.; Hugins, M.S.

    1983-01-01

    Hydrostatic bearings of a large vertical pump using sodium as the lubricant were critically examined to determine their ability to withstand seismic loads. Initial linear dynamics analyses predicted journal displacements to exceed bearing clearance by a ratio of 3:1. Equivalent time-history excitations were then developed from the response spectra to determine the number, magnitude, and duration of the bearing impact loads. Predicted loads were further reduced by 50% by modeling non-linear bearing characteristics normally present but not generally included in conventional linear analyses. Results are presented of the comprehensive design evaluation performed, based on these non-linear predictions, that assess stress, wear, and fatigue to demonstrate hydrostatic bearing integrity

  3. Hydrodynamic bearings

    CERN Document Server

    Bonneau, Dominique; Souchet, Dominique

    2014-01-01

    This Series provides the necessary elements to the development and validation of numerical prediction models for hydrodynamic bearings. This book describes the rheological models and the equations of lubrication. It also presents the numerical approaches used to solve the above equations by finite differences, finite volumes and finite elements methods.

  4. High hydrostatic pressure processing of tropical fruits.

    Science.gov (United States)

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

    2010-02-01

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

  5. Arsenolite: a quasi-hydrostatic solid pressure-transmitting medium

    International Nuclear Information System (INIS)

    Sans, J A; Manjón, F J; Popescu, C; Muñoz, A; Rodríguez-Hernández, P; Jordá, J L; Rey, F

    2016-01-01

    This study reports the experimental characterization of the hydrostatic properties of arsenolite (As 4 O 6 ), a molecular solid which is one of the softest minerals in the absence of hydrogen bonding. The high compressibility of arsenolite and its stability up to 15 GPa have been proved by x-ray diffraction measurements, and the progressive loss of hydrostaticity with increasing pressure up to 20 GPa has been monitored by ruby photoluminescence. Arsenolite has been found to exhibit hydrostatic behavior up to 2.5 GPa and a quasi-hydrostatic behavior up to 10 GPa at room temperature. This result opens the way to explore other molecular solids as possible quasi-hydrostatic pressure-transmitting media. The validity of arsenolite as an insulating, stable, non-penetrating and quasi-hydrostatic medium is explored by the study of the x-ray diffraction of zeolite ITQ-29 at high pressure. (paper)

  6. Are Hydrostatic Models Still Capable of Simulating Oceanic Fronts

    Science.gov (United States)

    2016-11-10

    Hydrostatic Models Still Capable of Simulating Oceanic Fronts Yalin Fan Zhitao Yu Ocean Dynamics and Prediction Branch Oceanography Division FengYan Shi...OF PAGES 17. LIMITATION OF ABSTRACT Are Hydrostatic Models Still Capable of Simulating Oceanic Fronts? Yalin Fan, Zhitao Yu, and, Fengyan Shi1 Naval...mixed layer and thermocline simulations as well as large scale circulations. Numerical experiments are conducted using hydrostatic (HY) and

  7. Journal Bearings

    Directory of Open Access Journals (Sweden)

    Renato Brancati

    1999-01-01

    determined after acquiring and analysing the orbits described by the journal axis for assigned unbalance values in different operating conditions. Analysis of the results shows some particular operating features that were not entirely predicted by the theoretical model and which may give rise to malfunctions in the rotor-tilting pad bearings system. The tests were carried out in the rotor dynamics laboratory of the Dipartimento di Ingegneria Meccanica per l'Energetica at the University of Naples.

  8. Determination of the full characteristics of a journal bearing for a fast reactor sodium pump using a full scale model bearing operating in water

    International Nuclear Information System (INIS)

    Gilroy, J.E.; Dostal, M.; Jones, R.P.

    1988-01-01

    This paper describes the analytical and experimental work carried out in support of a sodium-lubricated hydrostatic bearing for the CDFR primary sodium pump. The principle objective of the work was to establish bearing characteristics under steady-state and transient running conditions. A knowledge of these characteristics is necessary for the determination of the dynamic performance of the pump under normal and transient operating conditions and also under earthquake loading conditions

  9. Camshaft bearing arrangement

    Energy Technology Data Exchange (ETDEWEB)

    Aoi, K.; Ozawa, T.

    1986-06-10

    A bearing arrangement is described for the camshaft of an internal combustion engine or the like which camshaft is formed along its length in axial order with a first bearing surface, a first cam lobe, a second bearing surface, a second cam lobe, a third bearing surface, a third cam lobe and a fourth bearing surface, the improvement comprising first bearing means extending around substantially the full circumference of the first bearing surface and journaling the first bearing surface, second bearing means extending around substantially less than the circumference of the second bearing surface and journaling the second bearing surface, third bearing means extending around substantially less than the circumference of the third bearing surface and journaling the third bearing surface, and fourth bearing means extending around substantially the full circumference of the fourth bearing surface and journaling the first bearing surface.

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

    OpenAIRE

    V. Samorodov; A. Bondarenko

    2012-01-01

    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.

  11. Code of practice for the release of hydrostatic test water from hydrostatic testing of petroleum liquid and gas pipelines

    International Nuclear Information System (INIS)

    1999-01-01

    This booklet describes a series of administrative procedures regarding the code of practice in Alberta for the release of hydrostatic test water from hydrostatic testing of petroleum liquid and gas pipelines. The topics covered include the registration process, the type and quality of water to use during the test, and the analytical methods to be used. Reporting schedule and record keeping information are also covered. Schedule 1 discusses the requirements for the release of hydrostatic test water to land, while Schedule 2 describes the requirements for the release of hydrostatic test water to receiving water. 3 tabs

  12. Design and Analysis of Hydrostatic Transmission System

    Science.gov (United States)

    Mistry, Kayzad A.; Patel, Bhaumikkumar A.; Patel, Dhruvin J.; Parsana, Parth M.; Patel, Jitendra P.

    2018-02-01

    This study develops a hydraulic circuit to drive a conveying system dealing with heavy and delicate loads. Various safety circuits have been added in order to ensure stable working at high pressure and precise controlling. Here we have shown the calculation procedure based on an arbitrarily selected load. Also the circuit design and calculations of various components used is depicted along with the system simulation. The results show that the system is stable and efficient enough to transmit heavy loads by functioning of the circuit. By this information, one can be able to design their own hydrostatic circuits for various heavy loading conditions.

  13. Effect of elastic boundaries in hydrostatic problems

    Science.gov (United States)

    Volobuev, A. N.; Tolstonogov, A. P.

    2010-03-01

    The possibility and conditions of use of the Bernoulli equation for description of an elastic pipeline were considered. It is shown that this equation is identical in form to the Bernoulli equation used for description of a rigid pipeline. It has been established that the static pressure entering into the Bernoulli equation is not identical to the pressure entering into the impulse-momentum equation. The hydrostatic problem on the pressure distribution over the height of a beaker with a rigid bottom and elastic walls, filled with a liquid, was solved.

  14. 75 FR 48728 - The Hydrostatic Testing Provision of the Portable Fire Extinguishers Standard; Extension of the...

    Science.gov (United States)

    2010-08-11

    ... Hydrostatic Testing Provision of the Portable Fire Extinguishers Standard; Extension of the Office of... the information collection requirements contained in the Hydrostatic Testing provision of the Portable... 48729

  15. Imperfection effects on the buckling of hydrostatically loaded cylinders

    DEFF Research Database (Denmark)

    Pinna, Rodney; Madsen, Søren

    2015-01-01

    imperfection sensitivity. Work on cylinders with other loading conditions, such as hydrostatic loading, is more limited. Similarly, there is limited work on cylinders with boundary conditions other than simply-supported ends. This paper looks at the case of cylinders under hydrostatic load, which is often...

  16. 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…

  17. Sterically controlled mechanochemistry under hydrostatic pressure

    Science.gov (United States)

    Yan, Hao; Yang, Fan; Pan, Ding; Lin, Yu; Hohman, J. Nathan; Solis-Ibarra, Diego; Li, Fei Hua; Dahl, Jeremy E. P.; Carlson, Robert M. K.; Tkachenko, Boryslav A.; Fokin, Andrey A.; Schreiner, Peter R.; Galli, Giulia; Mao, Wendy L.; Shen, Zhi-Xun; Melosh, Nicholas A.

    2018-02-01

    Mechanical stimuli can modify the energy landscape of chemical reactions and enable reaction pathways, offering a synthetic strategy that complements conventional chemistry. These mechanochemical mechanisms have been studied extensively in one-dimensional polymers under tensile stress using ring-opening and reorganization, polymer unzipping and disulfide reduction as model reactions. In these systems, the pulling force stretches chemical bonds, initiating the reaction. Additionally, it has been shown that forces orthogonal to the chemical bonds can alter the rate of bond dissociation. However, these bond activation mechanisms have not been possible under isotropic, compressive stress (that is, hydrostatic pressure). Here we show that mechanochemistry through isotropic compression is possible by molecularly engineering structures that can translate macroscopic isotropic stress into molecular-level anisotropic strain. We engineer molecules with mechanically heterogeneous components—a compressible (‘soft’) mechanophore and incompressible (‘hard’) ligands. In these ‘molecular anvils’, isotropic stress leads to relative motions of the rigid ligands, anisotropically deforming the compressible mechanophore and activating bonds. Conversely, rigid ligands in steric contact impede relative motion, blocking reactivity. We combine experiments and computations to demonstrate hydrostatic-pressure-driven redox reactions in metal-organic chalcogenides that incorporate molecular elements that have heterogeneous compressibility, in which bending of bond angles or shearing of adjacent chains activates the metal-chalcogen bonds, leading to the formation of the elemental metal. These results reveal an unexplored reaction mechanism and suggest possible strategies for high-specificity mechanosynthesis.

  18. Modelling non-hydrostatic processes in sill regions

    Science.gov (United States)

    Souza, A.; Xing, J.; Davies, A.; Berntsen, J.

    2007-12-01

    We use a non-hydrostatic model to compute tidally induced flow and mixing in the region of bottom topography representing the sill at the entrance to Loch Etive (Scotland). This site is chosen since detailed measurements were recently made there. With non-hydrostatic dynamics in the model our results showed that the model could reproduce the observed flow characteristics, e.g., hydraulic transition, flow separation and internal waves. However, when calculations were performed using the model in the hydrostatic form, significant artificial convective mixing occurred. This influenced the computed temperature and flow field. We will discuss in detail the effects of non-hydrostatic dynamics on flow over the sill, especially investigate non-linear and non-hydrostatic contributions to modelled internal waves and internal wave energy fluxes.

  19. Non-hydrostatic layered flows over a sill

    International Nuclear Information System (INIS)

    Jamali, Mirmosadegh

    2013-01-01

    This work takes a new approach to solving non-hydrostatic equations of layered flows over bottom topography. A perturbation technique is used to find explicit expressions for a flow for different regimes of single- and two-layer flows over a sill. Excellent agreement with previous solutions and experimental data is obtained, and more details of the non-hydrostatic flow over a sill are revealed. The proposed method is simple and compact and removes the need for complex numerical techniques to solve the non-hydrostatic equations. It is shown that in the approach-controlled regime of two-layer flow over a sill, the flow upstream and farther downstream the sill crest can be described by the hydrostatic theory, and the flow is non-hydrostatic over only a short distance on the downstream side of the crest. (paper)

  20. Increased hydrostatic pressure enhances motility of lung cancer cells.

    Science.gov (United States)

    Kao, Yu-Chiu; Lee, Chau-Hwang; Kuo, Po-Ling

    2014-01-01

    Interstitial fluid pressures within most solid tumors are significantly higher than that in the surrounding normal tissues. Therefore, cancer cells must proliferate and migrate under the influence of elevated hydrostatic pressure while a tumor grows. In this study, we developed a pressurized cell culture device and investigated the influence of hydrostatic pressure on the migration speeds of lung cancer cells (CL1-5 and A549). The migration speeds of lung cancer cells were increased by 50-60% under a 20 mmHg hydrostatic pressure. We also observed that the expressions of aquaporin in CL1-5 and A549 cells were increased under the hydrostatic pressure. Our preliminary results indicate that increased hydrostatic pressure plays an important role in tumor metastasis.

  1. Breakdown of Hydrostatic Assumption in Tidal Channel with Scour Holes

    Directory of Open Access Journals (Sweden)

    Chunyan Li

    2016-10-01

    Full Text Available Hydrostatic condition is a common assumption in tidal and subtidal motions in oceans and estuaries.. Theories with this assumption have been largely successful. However, there is no definite criteria separating the hydrostatic from the non-hydrostatic regimes in real applications because real problems often times have multiple scales. With increased refinement of high resolution numerical models encompassing smaller and smaller spatial scales, the need for non-hydrostatic models is increasing. To evaluate the vertical motion over bathymetric changes in tidal channels and assess the validity of the hydrostatic approximation, we conducted observations using a vessel-based acoustic Doppler current profiler (ADCP. Observations were made along a straight channel 18 times over two scour holes of 25 m deep, separated by 330 m, in and out of an otherwise flat 8 m deep tidal pass leading to the Lake Pontchartrain over a time period of 8 hours covering part of the diurnal tidal cycle. Out of the 18 passages over the scour holes, 11 of them showed strong upwelling and downwelling which resulted in the breakdown of hydrostatic condition. The maximum observed vertical velocity was ~ 0.35 m/s, a high value in a tidal channel, and the estimated vertical acceleration reached a high value of 1.76×10-2 m/s2. Analysis demonstrated that the barotropic non-hydrostatic acceleration was dominant. The cause of the non-hydrostatic flow was the that over steep slopes. This demonstrates that in such a system, the bathymetric variation can lead to the breakdown of hydrostatic conditions. Models with hydrostatic restrictions will not be able to correctly capture the dynamics in such a system with significant bathymetric variations particularly during strong tidal currents.

  2. Magnetic bearings for free-piston Stirling engines

    Science.gov (United States)

    Curwen, P. W.; Fleming, D. P.; Rao, D. K.; Wilson, D. S.

    1992-01-01

    The feasibility and efficacy of applying magnetic bearings to free-piston Stirling-cycle power conversion machinery currently being developed for long-term space missions are assessed. The study was performed for a 50-kWe Reference Stirling Space Power Converter (RSSPC) which currently uses hydrostatic gas bearings to support the reciprocating displacer and power piston assemblies. Active magnetic bearings of the attractive electromagnetic type are feasible for the RSSPC power piston. Magnetic support of the displacer assembly would require unacceptable changes to the design of the current RSSPC. However, magnetic suspension of both displacer and power piston is feasible for a relative-displacer version of the RSSPC. Magnetic suspension of the RSSPC power piston can potentially increase overall efficiency by 0.5 to 1 percent (0.1 to 0.3 efficiency points). Magnetic bearings will also overcome several operational concerns associated with hydrostatic gas bearing systems. These advantages, however, are accompanied by a 5 percent increase in specific mass of the RSSPC.

  3. Effects of Hydrostatic Pressure on Carcinogenic Properties of Epithelia.

    Science.gov (United States)

    Tokuda, Shinsaku; Kim, Young Hak; Matsumoto, Hisako; Muro, Shigeo; Hirai, Toyohiro; Mishima, Michiaki; Furuse, Mikio

    2015-01-01

    The relationship between chronic inflammation and cancer is well known. The inflammation increases the permeability of blood vessels and consequently elevates pressure in the interstitial tissues. However, there have been only a few reports on the effects of hydrostatic pressure on cultured cells, and the relationship between elevated hydrostatic pressure and cell properties related to malignant tumors is less well understood. Therefore, we investigated the effects of hydrostatic pressure on the cultured epithelial cells seeded on permeable filters. Surprisingly, hydrostatic pressure from basal to apical side induced epithelial stratification in Madin-Darby canine kidney (MDCK) I and Caco-2 cells, and cavities with microvilli and tight junctions around their surfaces were formed within the multi-layered epithelia. The hydrostatic pressure gradient also promoted cell proliferation, suppressed cell apoptosis, and increased transepithelial ion permeability. The inhibition of protein kinase A (PKA) promoted epithelial stratification by the hydrostatic pressure whereas the activation of PKA led to suppressed epithelial stratification. These results indicate the role of the hydrostatic pressure gradient in the regulation of various epithelial cell functions. The findings in this study may provide clues for the development of a novel strategy for the treatment of the carcinoma.

  4. 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.

  5. 46 CFR 185.740 - Periodic servicing of hydrostatic release units.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 7 2010-10-01 2010-10-01 false Periodic servicing of hydrostatic release units. 185.740... Equipment § 185.740 Periodic servicing of hydrostatic release units. (a) Each hydrostatic release unit... specified by the Commandant. (b) Each disposable hydrostatic release unit must be marked with an expiration...

  6. 46 CFR 131.585 - Periodic servicing of hydrostatic-release units.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 4 2010-10-01 2010-10-01 false Periodic servicing of hydrostatic-release units. 131.585... OPERATIONS Tests, Drills, and Inspections § 131.585 Periodic servicing of hydrostatic-release units. (a) Except a disposable hydrostatic-release unit with an expiration date, each hydrostatic-release unit must...

  7. 46 CFR 122.740 - Periodic servicing of hydrostatic release units.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 4 2010-10-01 2010-10-01 false Periodic servicing of hydrostatic release units. 122.740... hydrostatic release units. (a) Each hydrostatic release unit, other than a disposable unit, must be serviced... hydrostatic release unit must be marked in clearly legible letters with an expiration date of two years after...

  8. Characterization and measurement of hybrid gas journal bearings

    Science.gov (United States)

    Lawrence, Tom Marquis

    developed to study in unprecedented detail the aerostatic component of the hybrid bearings. It is used to definitively compare the feedhole bearings to the porous liner bearings. The hydrostatic bearing efficiency (HBE) is defined and it is determined that the maximum achievable hydrostatic bearing efficiency (MAHBE) is determined solely by the bearing's mass addition configuration. The MAHBE of the porous liner bearings is determined to be over 5 times that of the feedhole bearings. The method also presents a means to tune the Kmeas to the clearance to achieve the MAHBE as well as giving a complete mapping of the hitherto misunderstood complex shapes of aerostatic load versus radial deflection curves. This method also rediscovers the obscure phenomenon of static instability which is called in this thesis the "near surface effect" and appears to be the first work to present a practical method to predict the range of static instability and quantify its resultant stiffness fall-off. It determines that porous liner type bearings are not subject to the phenomenon which appears for feedhole type bearings when the clearance exceeds a critical value relative to its mass-addition compensation. The standing pressure waves of hydrostatic and hybrid bearings with the 2 configurations of external pressurization as well as a geometrically identical hydrodynamic bearing are studied in detail under the methodology of the "CFD microscope". This method is used to characterize and identify the development, growth, and movement of the pressure wave extrema with increased hydrodynamic action (either increasing speed or increasing eccentricity). This method is also used to determine the "cause" of the "near surface effect". A gedanken experiment is performed based on these results which indicates that a bearing with a "stronger aerostatic strength" component should be more stable than one with a low aerostatic strength component. Numerical instability "speed limits" are found that are also

  9. Research on Parameter Design of Multi - axis Hydrostatic Transmission Vehicle

    Directory of Open Access Journals (Sweden)

    Zhao Liang

    2017-01-01

    Full Text Available In order to obtain reasonable parameters in the design of driving system of multi-axis hydrostatic transmission vehicle, the working principle of single-side drive of hydrostatic transmission vehicle is introduced. The matching and control of engine and hydraulic pump are analyzed. According to the driving equation of vehicle, The driving force required for driving system is determined, and the parameters of hydraulic motor, hydraulic pump, system working pressure and braking system are designed and calculated, which provides the parameter design for driving system of multi-axis hydrostatic transmission Reliable theoretical basis.

  10. Research on Travel Control System of Hydrostatic Transmission Chassis

    Directory of Open Access Journals (Sweden)

    Zhao Liang

    2017-01-01

    Full Text Available Aiming at the control problem of driving system of hydrostatic transmission chassis, the composition of the control system of hydrostatic transmission chassis is introduced and the control method of dual engine is solved. According to the number of driving axles in driving process, The external characteristic curve of the engine controls the variable hydraulic pump by one parameter, controls the rotational speed of the variable hydraulic motor according to the change of the vehicle speed, and introduces the control flow of the brake system. It provides a reference for the design of driving control system of multi-axis hydrostatic transmission chassis.

  11. Active control of multi-input hydraulic journal bearing system

    Science.gov (United States)

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

    2016-09-01

    Because of the advantages of high accuracy, high capacity, and low friction, the development of hydrostatic bearing for machine tool receives significant attention in the last decades. The mechanics and mechanical design of hydrostatic journal bearing with capillary restrictors has been discussed in literature. However, pragmatically, the undesired loading effects of cutting force tend to result in resonance and instability of the rotor and damage the shaft during operation. Therefore, multi-input, active flow control using state feedback design is proposed in this paper. To this purpose, the proportional pressure valves are added to the hydraulic system as active control devices, and the linearised models of the bearing and valve are discussed and identified. Simulation and experimental work is conducted to verify the proposed active control and parameter identification techniques. The results show that the unbalance responses of the rotor are reduced by the proposed state feedback controller, which is able to regulate the flow pressure effectively, thus enhancing the stability and accuracy of the hydraulic journal bearing.

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

    African Journals Online (AJOL)

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

  13. Hydrostatic Pressure Influences HIF-2 Alpha Expression in Chondrocytes

    Directory of Open Access Journals (Sweden)

    Hiroaki Inoue

    2015-01-01

    Full Text Available Hypoxia-inducible factor (HIF-2α is considered to play a major role in the progression of osteoarthritis. Recently, it was reported that pressure amplitude influences HIF-2α expression in murine endothelial cells. We examined whether hydrostatic pressure is involved in expression of HIF-2α in articular chondrocytes. Chondrocytes were cultured and stimulated by inflammation or hydrostatic pressure of 0, 5, 10, or 50 MPa. After stimulation, heat shock protein (HSP 70, HIF-2α, nuclear factor kappa B (NF-κB, matrix metalloproteinase (MMP-13, MMP-3, and vascular endothelial growth factor (VEGF gene expression were evaluated. The levels of all gene expression were increased by inflammatory stress. When chondrocytes were exposed to a hydrostatic pressure of 5 MPa, HIF-2α, MMP-13, and MMP-3 gene expression increased significantly although those of HSP70 and NF-κB were not significantly different from the control group. In contrast, HIF-2α gene expression did not increase under a hydrostatic pressure of 50 MPa although HSP70 and NF-κB expression increased significantly compared to control. We considered that hydrostatic pressure of 5 MPa could regulate HIF-2α independent of NF-κB, because the level of HIF-2α gene expression increased significantly without upregulation of NF-κB expression at 5 MPa. Hydrostatic pressure may influence cartilage degeneration, inducing MMP-13 and MMP-3 expression through HIF-2α.

  14. Hydrostatic pressure influences HIF-2 alpha expression in chondrocytes.

    Science.gov (United States)

    Inoue, Hiroaki; Arai, Yuji; Kishida, Tsunao; Terauchi, Ryu; Honjo, Kuniaki; Nakagawa, Shuji; Tsuchida, Shinji; Matsuki, Tomohiro; Ueshima, Keiichirou; Fujiwara, Hiroyoshi; Mazda, Osam; Kubo, Toshikazu

    2015-01-05

    Hypoxia-inducible factor (HIF)-2α is considered to play a major role in the progression of osteoarthritis. Recently, it was reported that pressure amplitude influences HIF-2α expression in murine endothelial cells. We examined whether hydrostatic pressure is involved in expression of HIF-2α in articular chondrocytes. Chondrocytes were cultured and stimulated by inflammation or hydrostatic pressure of 0, 5, 10, or 50 MPa. After stimulation, heat shock protein (HSP) 70, HIF-2α, nuclear factor kappa B (NF-κB), matrix metalloproteinase (MMP)-13, MMP-3, and vascular endothelial growth factor (VEGF) gene expression were evaluated. The levels of all gene expression were increased by inflammatory stress. When chondrocytes were exposed to a hydrostatic pressure of 5 MPa, HIF-2α, MMP-13, and MMP-3 gene expression increased significantly although those of HSP70 and NF-κB were not significantly different from the control group. In contrast, HIF-2α gene expression did not increase under a hydrostatic pressure of 50 MPa although HSP70 and NF-κB expression increased significantly compared to control. We considered that hydrostatic pressure of 5 MPa could regulate HIF-2α independent of NF-κB, because the level of HIF-2α gene expression increased significantly without upregulation of NF-κB expression at 5 MPa. Hydrostatic pressure may influence cartilage degeneration, inducing MMP-13 and MMP-3 expression through HIF-2α.

  15. Simultaneous influence of hydrostatic pressure and temperature on diamagnetic susceptibility of impurity doped quantum dots under the aegis of noise

    International Nuclear Information System (INIS)

    Saha, Surajit; Ganguly, Jayanta; Bera, Aindrila; Ghosh, Manas

    2016-01-01

    Highlights: • Diamagnetic susceptibility (DMS) of doped quantum dot is studied. • Hydrostatic pressure (HP) and temperature (T) affect DMS. • The dot is subjected to Gaussian white noise. • DMS also depends on mode of application of noise. - Abstract: 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.

  16. Simultaneous influence of hydrostatic pressure and temperature on diamagnetic susceptibility of impurity doped quantum dots under the aegis of noise

    Energy Technology Data Exchange (ETDEWEB)

    Saha, Surajit [Department of Chemistry, Physical Chemistry Section, Visva Bharati University, Santiniketan, Birbhum 731 235, West Bengal (India); Ganguly, Jayanta [Department of Chemistry, Brahmankhanda Basapara High School, Basapara, Birbhum 731215, West Bengal (India); Bera, Aindrila [Department of Chemistry, Physical Chemistry Section, Visva Bharati University, Santiniketan, Birbhum 731 235, West Bengal (India); Ghosh, Manas, E-mail: pcmg77@rediffmail.com [Department of Chemistry, Physical Chemistry Section, Visva Bharati University, Santiniketan, Birbhum 731 235, West Bengal (India)

    2016-11-30

    Highlights: • Diamagnetic susceptibility (DMS) of doped quantum dot is studied. • Hydrostatic pressure (HP) and temperature (T) affect DMS. • The dot is subjected to Gaussian white noise. • DMS also depends on mode of application of noise. - Abstract: 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.

  17. Design and fabrication of gas bearings for Brayton cycle rotating unit

    Science.gov (United States)

    Frost, A.; Tessarzik, J. M.; Arwas, E. B.; Waldron, W. D. (Editor)

    1973-01-01

    Analysis, design, and testing of two types of pivoted pad journal bearings and a spiral-grooved thrust bearing suitable for direct installation into the NASA 2 to 15 KW Brayton Cycle Rotating Unit (BRU) have been accomplished. Both types of tilting pad bearing assemblies are of the preloaded type, consisting of three pads with one pad flexibly mounted. One type utilizes a non-conforming pivot, while the other replaces the conventional spherical pivot with a cruciform flexible member. The thrust bearing is flexure mounted to accommodate static machine mislinement. Test results indicate that both types of journal bearings should satisfy the requirements imposed by the BRU. Hydrostatic tests of the spiral-grooved thrust bearing showed it to be free of pneumatic hammer with as many as 24 orifices over the BRU pressure and load range.

  18. Passive magnetic bearing configurations

    Science.gov (United States)

    Post, Richard F [Walnut Creek, CA

    2011-01-25

    A journal bearing provides vertical and radial stability to a rotor of a passive magnetic bearing system when the rotor is not rotating and when it is rotating. In the passive magnetic bearing system, the rotor has a vertical axis of rotation. Without the journal bearing, the rotor is vertically and radially unstable when stationary, and is vertically stable and radially unstable when rotating.

  19. Hydrostatic paradox: experimental verification of pressure equilibrium

    Science.gov (United States)

    Kodejška, Č.; Ganci, S.; Říha, J.; Sedláčková, H.

    2017-11-01

    This work is focused on the experimental verification of the balance between the atmospheric pressure acting on the sheet of paper, which encloses the cylinder completely or partially filled with water from below, where the hydrostatic pressure of the water column acts against the atmospheric pressure. First of all this paper solves a theoretical analysis of the problem, which is based, firstly, on the equation for isothermal process and, secondly, on the equality of pressures inside and outside the cylinder. From the measured values the confirmation of the theoretical quadratic dependence of the air pressure inside the cylinder on the level of the liquid in the cylinder is obtained, the maximum change in the volume of air within the cylinder occurs for the height of the water column L of one half of the total height of the vessel H. The measurements were made for different diameters of the cylinder and with plates made of different materials located at the bottom of the cylinder to prevent liquid from flowing out of the cylinder. The measured values were subjected to statistical analysis, which demonstrated the validity of the zero hypothesis, i.e. that the measured values are not statistically significantly different from the theoretically calculated ones at the statistical significance level α  =  0.05.

  20. 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.

  1. Hydrostatic equilibrium of stars without electroneutrality constraint

    Science.gov (United States)

    Krivoruchenko, M. I.; Nadyozhin, D. K.; Yudin, A. V.

    2018-04-01

    The general solution of hydrostatic equilibrium equations for a two-component fluid of ions and electrons without a local electroneutrality constraint is found in the framework of Newtonian gravity theory. In agreement with the Poincaré theorem on analyticity and in the context of Dyson's argument, the general solution is demonstrated to possess a fixed (essential) singularity in the gravitational constant G at G =0 . The regular component of the general solution can be determined by perturbation theory in G starting from a locally neutral solution. The nonperturbative component obtained using the method of Wentzel, Kramers and Brillouin is exponentially small in the inner layers of the star and grows rapidly in the outward direction. Near the surface of the star, both components are comparable in magnitude, and their nonlinear interplay determines the properties of an electro- or ionosphere. The stellar charge varies within the limits of -0.1 to 150 C per solar mass. The properties of electro- and ionospheres are exponentially sensitive to variations of the fluid densities in the central regions of the star. The general solutions of two exactly solvable stellar models without a local electroneutrality constraint are also presented.

  2. Compensation of Cross-Coupling Stiffness and Increase of Direct Damping in Multirecess Journal Bearings using Active Hybrid Lubrication

    DEFF Research Database (Denmark)

    Santos, Ilmar; Watanabe, F.Y.

    2004-01-01

    journal bearings (HJB). When part of hydrostatic pressure is also dynamically modified by means of hydraulic control systems, one refers to the active lubrication. The main contribution of the present theoretical work is to show that it is possible to reduce cross-coupling stiffness and increase...

  3. Well balanced finite volume methods for nearly hydrostatic flows

    International Nuclear Information System (INIS)

    Botta, N.; Klein, R.; Langenberg, S.; Luetzenkirchen, S.

    2004-01-01

    In numerical approximations of nearly hydrostatic flows, a proper representation of the dominant hydrostatic balance is of crucial importance: unbalanced truncation errors can induce unacceptable spurious motions, e.g., in dynamical cores of models for numerical weather prediction (NWP) in particular near steep topography. In this paper we develop a new strategy for the construction of discretizations that are 'well-balanced' with respect to dominant hydrostatics. The classical idea of formulating the momentum balance in terms of deviations of pressure from a balanced background distribution is realized here through local, time dependent hydrostatic reconstructions. Balanced discretizations of the pressure gradient and of the gravitation source term are achieved through a 'discrete Archimedes' buoyancy principle'. This strategy is applied to extend an explicit standard finite volume Godunov-type scheme for compressible flows with minimal modifications. The resulting method has the following features: (i) It inherits its conservation properties from the underlying base scheme. (ii) It is exactly balanced, even on curvilinear grids, for a large class of near-hydrostatic flows. (iii) It solves the full compressible flow equations without reference to a background state that is defined for an entire vertical column of air. (iv) It is robust with respect to details of the implementation, such as the choice of slope limiting functions, or the particularities of boundary condition discretizations

  4. 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...

  5. Hydrostatic pressure mimics gravitational pressure in characean cells

    Science.gov (United States)

    Staves, M. P.; Wayne, R.; Leopold, A. C.

    1992-01-01

    Hydrostatic pressure applied to one end of a horizontal Chara cell induces a polarity of cytoplasmic streaming, thus mimicking the effect of gravity. A positive hydrostatic pressure induces a more rapid streaming away from the applied pressure and a slower streaming toward the applied pressure. In contrast, a negative pressure induces a more rapid streaming toward and a slower streaming away from the applied pressure. Both the hydrostatic pressure-induced and gravity-induced polarity of cytoplasmic streaming respond identically to cell ligation, UV microbeam irradiation, external Ca2+ concentrations, osmotic pressure, neutral red, TEA Cl-, and the Ca2+ channel blockers nifedipine and LaCl3. In addition, hydrostatic pressure applied to the bottom of a vertically-oriented cell can abolish and even reverse the gravity-induced polarity of cytoplasmic streaming. These data indicate that both gravity and hydrostatic pressure act at the same point of the signal transduction chain leading to the induction of a polarity of cytoplasmic streaming and support the hypothesis that characean cells respond to gravity by sensing a gravity-induced pressure differential between the cell ends.

  6. Oil-free bearing development for high-speed turbomachinery in distributed energy systems – dynamic and environmental evaluation

    Directory of Open Access Journals (Sweden)

    Tkacz Eliza

    2015-09-01

    Full Text Available Modern distributed energy systems, which are used to provide an alternative to or an enhancement of traditional electric power systems, require small size highspeed rotor turbomachinery to be developed. The existing conventional oil-lubricated bearings reveal performance limits at high revolutions as far as stability and power loss of the bearing are concerned. Non-conventional, oil-free bearings lubricated with the machine working medium could be a remedy to this issue. This approach includes a correct design of the machine flow structure and an accurate selection of the bearing type. Chosen aspects of the theoretical and experimental investigations of oil-free bearings and supports; including magnetic, tilting pad, pressurized aerostatic and hydrostatic bearings as well as some applications of oil-free bearing technology for highspeed turbomachinery; are described in the paper.

  7. Liquid crystalline fiber optic colorimeter for hydrostatic pressure measurement

    Science.gov (United States)

    Wolinski, Tomasz R.; Bajdecki, Waldemar K.; Domanski, Andrzej W.; Karpierz, Miroslaw A.; Konopka, Witold; Nasilowski, T.; Sierakowski, Marek W.; Swillo, Marcin; Dabrowski, Roman S.; Nowinowski-Kruszelnicki, Edward; Wasowski, Janusz

    2001-08-01

    This paper presents results of tests performed on a fiber optic system of liquid crystalline transducer for hydrostatic pressure monitoring based on properties of colorimetry. The system employs pressure-induced deformations occurring in liquid crystalline (LC) cells configured in a homogeneous Frederiks geometry. The sensor is compared of a round LC cell placed inside a specially designed pressure chamber. As a light source we used a typical diode operating at red wavelength and modulated using standard techniques. The pressure transducer was connected to a computer with a specially designed interface built on the bas of advanced ADAM modules. Results indicate that the system offers high response to pressure with reduced temperature sensitivity and, depending on the LC cell used, can be adjusted for monitoring of low hydrostatic pressures up to 6 MPa. These studies have demonstrated the feasibility of fiber optic liquid crystal colorimeter for hydrostatic pressure sensing specially dedicated to pipe- lines, mining instrumentation, and process-control technologies.

  8. Characteristics of hydrostatically extruded Zr-2.5Nb alloy

    International Nuclear Information System (INIS)

    Jie, Z.; Jiaqi, D.; Tieqi, Y.; Wenxian, H.; Yan, L.; Yunxia, Z.; Zhenhe, L.

    1984-01-01

    Hydrostatic extrusion is a new production technology. Zr-2.5Nb alloy tubes cold hydrostatically extruded possess excellent mechanical properties similar to heat-treated tubes and better than cold-worked tubes. Examination by transmission electron microscope shows that the alloy is of a uniform cell substructure containing the (α + β) phases, which is one of important factors improving properties of the alloy. The study of texture, stress, and reorientation of the hydride shows that hydrostatically extruded tubes with basal plane normals in the radial direction have obviously higher hydride reorientation threshold stress than tubes with basal plane normals in the circumferential direction. Moreover, investigation of fracture toughness reveals that hydride distributed perpendicular to the crack propagation direction restrains further propagation of the crack. It is favorable for preserving the fracture resistance of the material

  9. Hydrostaticity of Pressure Media in Diamond Anvil Cells

    International Nuclear Information System (INIS)

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

    2009-01-01

    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 R 1 – R 2 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 R 1 – R 2 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

  10. Hydrostatic and Flow Measurements on Wrinkled Membrane Walls

    Science.gov (United States)

    Ozsun, Ozgur; Ekinci, Kamil

    2013-03-01

    In this study, we investigate structural properties of wrinkled silicon nitride (SiN) membranes, under both hydrostatic perturbations and flow conditions, through surface profile measurements. Rectangular SiN membranes with linear dimensions of 15 mm × 1 . 5 mm × 1 μ m are fabricated on a 500 - μ m-thick silicon substrate using standard lithography techniques. These thin, initially flat, tension-dominated membranes are wrinkled by bending the silicon substrate. The wrinkled membranes are subsequently incorporated as walls into rectangular micro-channels, which allow both hydrostatic and flow measurements. The structural response of the wrinkles to hydrostatic pressure provides a measure of the various energy scales in the problem. Flow experiments show that the elastic properties and the structural undulations on a compliant membrane completely dominate the flow, possibly providing drag reduction. These measurements pave the way for building and using compliant walls for drag reduction in micro-channels.

  11. Dislocations and point defects in hydrostatically compressed crystal

    International Nuclear Information System (INIS)

    Kosevich, A.M.; Tokij, V.V.; Strel'tsov, V.A.

    1978-01-01

    Within the framework of the theory of finite deformations, the elastic fields are considered, which are induced by the sources of internal stresses in a crystal compressed under a high pressure. In the case of a hydrostatically compressed crystal with defects, the use of a variation principle is discussed. Using the smallness of distorsions, the linear theory of elastic fields of defects in the crystal compressed under a high pressure, is developed. An analysis of the main relationships of the theory results in the following conclusion: in a course of the linear approximation the taking into account of the hydrostatic pressure brings to the renorming of the elasticity moduli and to the replacing of the hydrostatic parameters of defects by their values in the compressed crystal. That conclusion allows the results of the elasticity linear theory of the crystal with defects to be used to the full extent

  12. Hydrostatic high pressures for material deformations. Application to Chevrel phase superconductors

    International Nuclear Information System (INIS)

    Massat, H.

    1984-01-01

    The effect of hydrostatic high pressures on the ductility of materials is reviewed and applications are made to powder metallurgy under isostatic pressure and hydrostatic extrusion of superconductors [fr

  13. Hydrostatic Water Level Systems At Homestake DUSEL

    Science.gov (United States)

    Stetler, L. D.; Volk, J. T.

    2009-12-01

    Two arrays of Fermilab-style hydrostatic water level sensors have been installed in the former Homestake gold mine in Lead, SD, the site of the new Deep Underground Science and Engineering Laboratory (DUSEL). Sensors were constructed at Fermilab from 8.5 cm diameter PVC pipe (housing) that was sealed on the ends and fit with a proximity sensor. The instrument have a height of 10 cm. Two ports in each sensor housing provide for connectivity, the upper port for air and the bottom port for water. Multiple instruments connected in series provide a precise water level and differences in readings between successive sensors provide for ground tilt to be resolved. Sensor resolution is 5 μm per count and has a range of approximately 1.25 cm. Data output from each sensor is relayed to a Fermilab-constructed readout card that also has temperature/relative humidity and barometric pressure sensors connected. All data are relayed out of the mine by fiber optic cable and can be recorded by Ethernet at remote locations. The current arrays have been installed on the 2000-ft level (610 m) and consist of six instruments in each array. Three sensors were placed in a N-S oriented drift and three in an E-W oriented drift. Using this orientation, it is anticipated that tilt direction may be resolved in addition to overall tilt magnitude. To date the data show passage of earth tides and frequency analysis has revealed five components to this signal, three associated with the semi-diurnal (~12.4 hr) and two with the diurnal (~24.9 hr) tides. Currently, installation methods are being analyzed between concrete pillar and rib-mounting using the existing setup on the 2000-ft level. Using these results, two additional arrays of Fermilab instruments will be installed on the 4550-ft and 4850-ft levels (1387 and 1478 m, respectively). In addition to Fermilab instruments, several high resolution Budker tiltmeters (1 μm resolution) will be installed in the mine workings in the near future, some

  14. Teddy Bear Stories

    DEFF Research Database (Denmark)

    van Leeuwen, Theo; Caldas-Coulthardt, Carmen

    2014-01-01

    This paper presents a semiotic analysis of a key cultural artefact, the teddy bear. After introducing the iconography of the teddy bear, it analyses different kinds of stories to show how teddy bears are endowed with meaning in everyday life: stories from children's books, reminiscenses by adults...... bears have traditionally centred on interpersonal relations within the nuclear family, but have recently been institutionalized and commercialized....

  15. Radial oil injection applied to main engine bearings: evaluation of injection control rules

    DEFF Research Database (Denmark)

    Estupiñan, EA; Santos, Ilmar

    2012-01-01

    , the dynamic behaviour of the main bearing of a medium-size engine is theoretically analysed when the engine operates with controllable radial oil injection and four different injection control rules. The theoretical investigation is based on a single-cylinder combustion engine model. The performance......The performance of main bearings in a combustion engine affects key functions such as durability, noise and vibration. Thus, with the aim of reducing friction losses and vibrations between the crankshaft and the bearings, the work reported here evaluates different strategies for applying...... controllable radial oil injection to main crankshaft journal bearings. In an actively lubricated bearing, conventional hydrodynamic lubrication is combined with controllable hydrostatic lubrication, where the oil injection pressures can be modified depending on the operational conditions. In this study...

  16. High-purity aluminium creep under high hydrostatic pressure

    International Nuclear Information System (INIS)

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

    1977-01-01

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

  17. 46 CFR 54.10-10 - Standard hydrostatic test (modifies UG-99).

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 2 2010-10-01 2010-10-01 false Standard hydrostatic test (modifies UG-99). 54.10-10... PRESSURE VESSELS Inspection, Reports, and Stamping § 54.10-10 Standard hydrostatic test (modifies UG-99). (a) All pressure vessels shall satisfactorily pass the hydrostatic test prescribed by this section...

  18. 46 CFR 56.97-30 - Hydrostatic tests (modifies 137.4).

    Science.gov (United States)

    2010-10-01

    ... 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 of... system is filling. (b) Test medium and test temperature. (1) Water will be used for a hydrostatic leak...

  19. 78 FR 70324 - Thy Hydrostatic Testing Provision of the Portable Fire Extinguishers Standard; Extension of the...

    Science.gov (United States)

    2013-11-25

    ... Hydrostatic Testing Provision of the Portable Fire Extinguishers Standard; Extension of the Office of...) approval of the information collection requirements contained in the Hydrostatic Testing provision of the... Hydrostatic Testing Provision of the Portable Fire Extinguishers Standard are necessary to reduce workers...

  20. Measurement of small values of hydrostatic pressure difference / Pomiar małych wartości różnicy ciśnień hydrostatycznych

    Science.gov (United States)

    Broda, Krzysztof; Filipek, Wiktor

    2012-10-01

    In order to describe the fluid flow through the porous centre, made of identical spheres, it is necessary to know the pressure, but in fact - the pressure distribution. For the flows in the range that was traditionally called laminar flow (i. e. for Reynolds numbers (Bear, 1988; Duckworth, 1983; Troskolański, 1957) from the range 0,01 to 3) it is virtually impossible with the use of the tools directly available on the market. Therefore, many scientists who explore this problem have concentrated only on the research of the velocity distribution of the medium that penetrates the intended centre (Bear, 1988) or pressure distribution at high hydraulic gradients (Trzaska & Broda, 1991, 2000; Trzaska et al., 2005). It may result from the inaccessibility to the measurement methods that provide measurement of very low hydrostatic pressures, such as pressure resulting from the weight of liquid located in the gravitational field (Duckworth, 1983; Troskolański, 1957). The pressure value c. 10 Pa (Troskolański, 1957) can be generated even by 1 mm height difference between the two levels of the free water surface, which in fact constitutes the definition of gauging tools of today measuring the level of the hydrostatic pressure. Authors proposed a method of hydrostatic pressure measurement and devised a gauging tool. Then a series of tests was conducted aiming at establishing what is the influence of various factors, such as temperature, atmospheric pressure, velocity of measurement completion, etc. on the accuracy and method of measurements. A method for considerable reduction of hysteresis that occurs during measurement was also devised. The method of measurement of small hydrostatic difference measurements allows for the accuracy of measurement of up to 0.5 Pa. Measurement results can be improved successfully by one order of magnitude, which for sure would entail necessary temperature stabilization of the tool. It will be more difficult though to compensate the influence

  1. A Rotary Microactuator Supported on Encapsulated Microball Bearings using an Electro-Pneumatic Thrust Balance

    Science.gov (United States)

    2009-01-01

    Additionally, high-speed air bearings have been demonstrated in micromotors (55 000 rpm) and micro-turbomachinery (2 million rpm) [7, 8]. While...without thrust balances [11]. For applications requiring continuous rotation ( micromotors and micropumps) this hydrostatic balancing force can be...conditions for stable actuation of the micromotor leading to maximum speeds. In addition to increased speed, this device demonstrates a substantial

  2. Magnetic phase transitions and hydrostatic pressure or uniaxial stress experiments

    International Nuclear Information System (INIS)

    Bloch, D.

    1980-01-01

    Crystals submitted to high hydrostatic pressure or uniaxial stress have been investigated by means of neutron scattering. The techniques used are described and applications to pressure or stress induced T = 0 magnetic to nonmagnetic transitions (Pr,PrSb) and continuous to discontinuous order-disorder transitions (MnO) are given. (orig.)

  3. A single-institution experience with hydrostatic reduction for ...

    African Journals Online (AJOL)

    Background/purpose Hydrostatic reduction for intussusception has the benefit ... The v2-test was used to compare categorical variables, and a P value of 0.05 was ... Conclusion Although less than half of the patients presenting with childhood ...

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

    African Journals Online (AJOL)

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

  5. Hydrostatic reduction of intussusception with normal saline using the ...

    African Journals Online (AJOL)

    Hydrostatic reduction of intussusception with normal saline using the gravity aided method in a Nigerian teaching hospital. M.A. Abdulsalam, B.O. Balogun, R.I. Osuoji, O.O. Olofinlade, O.M. Faboya, M.A. Bankole ...

  6. N2 vs H20 as purge/hydrostatic head

    International Nuclear Information System (INIS)

    Mast, J.C.

    1996-01-01

    This document provides the information to explain to the customer the ETP for the N2 vs H20 as Purge/Hydrostatic Head. This ETP follows the format described in Issurance of New Characterization Equipment Engineering Desk Instructions, 75200-95-013

  7. static analysis of circular cylindrical shell under hydrostatic and ring

    African Journals Online (AJOL)

    DEPT OF AGRICULTURAL ENGINEERING

    (Golzan et al, 2008). Circular cylindrical shells are used in a large variety of civil engineering structures, e.g. off-shore platforms, chimneys, silos, pipelines, bridge arches or wind turbine towers (Winterstetter et al, 2002). This work is concerned with the analysis of circular cylindri- cal shell subjected to hydrostatic pressure in.

  8. Intussusception in children: Hydrostatic reduction under US guidance - own experience

    International Nuclear Information System (INIS)

    Roik, D.; Brzewski, M.; Biejat, A.; Marcinski, M.

    2008-01-01

    Intussusception in children is a common abdominal emergency. Recent years have brought a New promising method of nonsurgical invagination treatment, hydrostatic reduction under sonographic (US) guidance. The major advantage of this method is lack of the ionized radiation. The aim of our study is to asses the safety and effectiveness of hydrostatic reduction under US guidance used as a first choice method of invagination treatment in our department. >From July 2006 to December 2007, 33 procedures of hydrostatic reduction under US guidance were performed in 27 children, aged from 7 months to 6 years and 10 months. The procedure was performed in US room by radiologist and surgeon with the use of self-constructed set for saline enema. The sedation of patient was routinely performed. The initial procedure was effective in 23 patients (pts) (85%). In 5 pts the recurrence of intussusception occurred and in 3 of them next attempt of the reduction was successful. In 4 cases the initial procedures failed, and those children were operated. Total amount of 6 pts underwent an operation. We do not observe any complications connected with the procedure. Hydrostatic reduction of children intusussception under US-guidance is safe and effective method. Our initial results meet the recommended limits of successful reduction rates. It encouraged us to evaluation and further implementation of this method. Water enema is a first choice method of invagination treatment in our hospital. (authors)

  9. Anomalies of ultrasound attenuation in metals under hydrostatic pressure

    International Nuclear Information System (INIS)

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

    1978-01-01

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

  10. Effect of hydrostatic pressure on magnetic phase transitions and magnetization in gadolinium monocrystal

    International Nuclear Information System (INIS)

    Nikitin, S.A.; Bezdushnyj, R.V.

    1989-01-01

    Effect of hydrostatic pressure on magnetization in gadolinium monocrystal (Δσ-effect) was investigated. Dependences of spesific magnetization, Δσ-effect and bulk magnetostriction of gadolinium monocrystal on temperatures were studied. Results of conducted investigation have shown that in gadolinium the change of specific magnetization under the hydrostatic pressure effect is caused in general case by three effects: a)change of spontaneous magnetization under the effect of hydrostatic pressure; b)change of magnetization within technical magnetization range due to the effect of hydrostatic pressure on magnetic anisotropy constants; c)change of magnetization due to the effect of hydrostatic pressure on temperature of spin-reoriented transition

  11. The Influence of Injection Pockets on the Performance of Tilting-Pad Thrust Bearings - Part I: Theory

    DEFF Research Database (Denmark)

    Heinrichson, Niels; Santos, Ilmar; Fuerst, Axel

    2007-01-01

    This is Part I of a two-part series of papers describing the effects of high-pressure injection pockets on the operating conditions of tilting-pad thrust bearings. In Part I a numerical model based on the Reynolds equation is developed extending the threedimensional thermoelastohydrodynamic (TEHD......) analysis of tilting-pad thrust bearings to include the effects of high-pressure injection and recesses in the bearing pads. The model is applied to the analysis of an existing bearing of large dimensions and the influence of the pocket is analyzed. In the analysis, the high-pressure oil injection used...... for hydrostatic jacking is turned off (i.e., only the effect of the pocket is studied). It is shown that a shallow pocket positively influences the performance of the bearing because it has characteristics similar to those of a Rayleigh-step bearing. In Part II of the paper (Heinrichson, N., Fuerst, A...

  12. A feasibility assessment of magnetic bearings for free-piston Stirling space power converters

    Science.gov (United States)

    Curwen, Peter W.; Rao, Dantam K.; Wilson, Donald R.

    1992-01-01

    This report describes a design and analysis study performed by Mechanical Technology Incorporated (MTI) under NASA Contract NAS3-26061. The objective of the study was to assess the feasibility and efficacy of applying magnetic bearings to free-piston Stirling-cycle power conversion machinery of the type currently being evaluated for possible use in long-term space missions. The study was performed for a 50-kWe Reference Stirling Space Power Converter (RSSPC) system consisting of two 25-kWe free-piston Stirling engine modules. Two different versions of the RSSPC engine modules have been defined under NASA Contract NAS3-25463. These modules currently use hydrostatic gas bearings to support the reciprocating displacer and power piston assemblies. Results of this study show that active magnetic bearings of the attractive electromagnetic type are technically feasible for RSSPC application provided that wire insulation with 60,000-hr life capability at 300 C can be developed for the bearing coils. From a design integration standpoint, both versions of the RSSPC were found to be conceptually amenable to magnetic support of the power piston assembly. However, only one version of the RSSPC was found to be amendable to magnetic support of the displacer assembly. Unacceptable changes to the basic engine design would be required to incorporate magnetic displacer bearings into the second version. Complete magnetic suspension of the RSSPC can potentially increase overall efficiency of the Stirling cycle power converter by 0.53 to 1.4 percent (0.15 to 0.4 efficiency points). Magnetic bearings will also overcome several operational concerns associated with hydrostatic gas bearing systems. However, these advantages are accompanied by a 5 to 8 percent increase in specific mass of the RSSPC, depending on the RSSPC version employed. Additionally, magnetic bearings are much more complex, both mechanically and particularly electronically, than hydrostatic bearings. Accordingly, long

  13. Polar bears, Ursus maritimus

    Science.gov (United States)

    Rode, Karyn D.; Stirling, Ian

    2017-01-01

    Polar bears are the largest of the eight species of bears found worldwide and are covered in a pigment-free fur giving them the appearance of being white. They are the most carnivorous of bear species consuming a high-fat diet, primarily of ice-associated seals and other marine mammals. They range throughout the circumpolar Arctic to the southernmost extent of seasonal pack ice.

  14. EcoBears

    DEFF Research Database (Denmark)

    Nielsen, Nick; Pedersen, Sandra Bleuenn; Sørensen, Jens Ager

    2015-01-01

    In this paper, we introduce the EcoBears concept that aims to augment household appliances with functional and aesthetic features to promote their "use'' and "longevity of use'' to prevent their disposal. The EcoBears also aim to support the communication of environmental issues in the home setting....... We present our initial design and implementation of the EcoBears that consist of two bear modules (a mother and her cub). We also present our preliminary concept validations and lessons learned to be considered for future directions....

  15. Bearing restoration by grinding

    Science.gov (United States)

    Hanau, H.; Parker, R. J.; Zaretsky, E. V.; Chen, S. M.; Bull, H. L.

    1976-01-01

    A joint program was undertaken by the NASA Lewis Research Center and the Army Aviation Systems Command to restore by grinding those rolling-element bearings which are currently being discarded at aircraft engine and transmission overhaul. Three bearing types were selected from the UH-1 helicopter engine (T-53) and transmission for the pilot program. No bearing failures occurred related to the restoration by grinding process. The risk and cost of a bearing restoration by grinding programs was analyzed. A microeconomic impact analysis was performed.

  16. Polar bears at risk

    Energy Technology Data Exchange (ETDEWEB)

    Norris, S.; Rosentrater, L.; Eid, P.M. [WWF International Arctic Programme, Oslo (Norway)

    2002-05-01

    Polar bears, the world's largest terrestrial carnivore, spend much of their lives on the arctic sea ice. This is where they hunt and move between feeding, denning, and resting areas. The world population, estimated at 22,000 bears, is made up of 20 relatively distinct populations varying in size from a few hundred to a few thousand animals. About 60 per cent of all polar bears are found in Canada. In general, the status of this species is stable, although there are pronounced differences between populations. Reductions in the extent and thickness of sea ice has lead the IUCN Polar Bear Specialist Group to describe climate change as one of the major threats facing polar bears today. Though the long-term effects of climate change will vary in different areas of the Arctic, impacts on the condition and reproductive success of polar bears and their prey are likely to be negative. Longer ice-free periods resulting from earlier break-up of sea ice in the spring and later formation in the fall is already impacting polar bears in the southern portions of their range. In Canada's Hudson Bay, for example, bears hunt on the ice through the winter and into early summer, after which the ice melts completely, forcing bears ashore to fast on stored fat until freeze-up in the fall. The time bears have on the ice to hunt and build up their body condition is cut short when the ice melts early. Studies from Hudson Bay show that for every week earlier that ice break-up occurs, bears will come ashore 10 kg lighter and in poorer condition. It is likely that populations of polar bears dividing their time between land and sea will be severely reduced and local extinctions may occur as greenhouse gas emissions continue to rise and sea ice melts. Expected changes in regional weather patterns will also impact polar bears. Rain in the late winter can cause maternity dens to collapse before females and cubs have departed, thus exposing occupants to the elements and to predators. Such

  17. Mechanical Stimulation of Adipose-Derived Stem Cells for Functional Tissue Engineering of the Musculoskeletal System via Cyclic Hydrostatic Pressure, Simulated Microgravity, and Cyclic Tensile Strain.

    Science.gov (United States)

    Nordberg, Rachel C; Bodle, Josie C; Loboa, Elizabeth G

    2018-01-01

    It is critical that human adipose stem cell (hASC) tissue-engineering therapies possess appropriate mechanical properties in order to restore function of the load bearing tissues of the musculoskeletal system. In an effort to elucidate the hASC response to mechanical stimulation and develop mechanically robust tissue engineered constructs, recent research has utilized a variety of mechanical loading paradigms including cyclic tensile strain, cyclic hydrostatic pressure, and mechanical unloading in simulated microgravity. This chapter describes methods for applying these mechanical stimuli to hASC to direct differentiation for functional tissue engineering of the musculoskeletal system.

  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. Hydrostatic Equilibria of Rotating Stars with Realistic Equation of State

    Science.gov (United States)

    Yasutake, Nobutoshi; Fujisawa, Kotaro; Okawa, Hirotada; Yamada, Shoichi

    Stars rotate generally, but it is a non-trivial issue to obtain hydrostatic equilibria for rapidly rotating stars theoretically, especially for baroclinic cases, in which the pressure depends not only on the density, but also on the temperature and compositions. It is clear that the stellar structures with realistic equation of state are the baroclinic cases, but there are not so many studies for such equilibria. In this study, we propose two methods to obtain hydrostatic equilibria considering rotation and baroclinicity, namely the weak-solution method and the strong-solution method. The former method is based on the variational principle, which is also applied to the calculation of the inhomogeneous phases, known as the pasta structures, in crust of neutron stars. We found this method might break the balance equation locally, then introduce the strong-solution method. Note that our method is formulated in the mass coordinate, and it is hence appropriated for the stellar evolution calculations.

  20. 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.

  1. Achieving Textbook Multigrid Efficiency for Hydrostatic Ice Sheet Flow

    KAUST Repository

    Brown, Jed; Smith, Barry; Ahmadia, Aron

    2013-01-01

    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.

  2. Hydrostatic compression of Fe(1-x)O wuestite

    Science.gov (United States)

    Jeanloz, R.; Sato-Sorensen, Y.

    1986-01-01

    Hydrostatic compression measurements on Fe(0.95)O wuestite up to 12 GPa yield a room temperature value for the isothermal bulk modulus of K(ot) = 157 (+ or - 10) GPa at zero pressure. This result is in accord with previous hydrostatic and nonhydrostatic measurements of K(ot) for wuestites of composition: 0.89 = Fe/O 0.95. Dynamic measurements of the bulk modulus by ultrasonic, shock-wave and neutron-scattering experiments tend to yield a larger value: K(ot) approximately 180 GPa. The discrepancy between static and dynamic values cannot be explained by the variation of K(ot) with composition, as has been proposed. This conclusion is based on high-precision compression data and on theoretical models of the effects of defects on elastic constants. Barring serious errors in the published measurements, the available data suggest that wuestite exhibits a volume relaxation under pressure.

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

    International Nuclear Information System (INIS)

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

    1979-01-01

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

  4. Hydrostatic Pressure Sensing with High Birefringence Photonic Crystal Fibers

    Science.gov (United States)

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

    2010-01-01

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

  5. Thermohydrodynamic analysis of cryogenic liquid turbulent flow fluid film bearings, phase 2

    Science.gov (United States)

    Sanandres, Luis

    1994-01-01

    The Phase 2 (1994) Annual Progress Report presents two major report sections describing the thermal analysis of tilting- and flexure-pad hybrid bearings, and the unsteady flow and transient response of a point mass rotor supported on fluid film bearings. A literature review on the subject of two-phase flow in fluid film bearings and part of the proposed work for 1995 are also included. The programs delivered at the end of 1994 are named hydroflext and hydrotran. Both codes are fully compatible with the hydrosealt (1993) program. The new programs retain the same calculating options of hydrosealt plus the added bearing geometries, and unsteady flow and transient forced response. Refer to the hydroflext & hydrotran User's Manual and Tutorial for basic information on the analysis and instructions to run the programs. The Examples Handbook contains the test bearing cases along with comparisons with experimental data or published analytical values. The following major tasks were completed in 1994 (Phase 2): (1) extension of the thermohydrodynamic analysis and development of computer program hydroflext to model various bearing geometries, namely, tilting-pad hydrodynamic journal bearings, flexure-pad cylindrical bearings (hydrostatic and hydrodynamic), and cylindrical pad bearings with a simple elastic matrix (ideal foil bearings); (2) improved thermal model including radial heat transfer through the bearing stator; (3) calculation of the unsteady bulk-flow field in fluid film bearings and the transient response of a point mass rotor supported on bearings; and (4) a literature review on the subject of two-phase flows and homogeneous-mixture flows in thin-film geometries.

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

    OpenAIRE

    Németh Cs.; Castillo L. A.; Horváth F.; Zeke I.; Friedrich L.; Balla Cs.; Németh Z.; Póti P.

    2015-01-01

    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 indu...

  7. HIGH HYDROSTATIC PRESSURE SYSTEMS USE IN FOOD INDUSTRY

    OpenAIRE

    Yahya TÜLEK; Gökçe FİLİZAY

    2006-01-01

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

  8. Enhanced performance of ferroelectric materials under hydrostatic pressure

    Science.gov (United States)

    Chauhan, Aditya; Patel, Satyanarayan; Wang, Shuai; Novak, Nikola; Xu, Bai-Xiang; Lv, Peng; Vaish, Rahul; Lynch, Christopher S.

    2017-12-01

    Mechanical confinement or restricted degrees of freedom have been explored for its potential to enhance the performance of ferroelectric devices. It presents an easy and reversible method to tune the response for specific applications. However, such studies have been mainly limited to uni- or bi-axial stress. This study investigates the effect of hydrostatic pressure on the ferroelectric behavior of bulk polycrystalline Pb0.99Nb0.02(Zr0.95Ti0.05)0.98O3. Polarization versus electric field hysteresis plots were generated as a function of hydrostatic pressure for a range of operating temperatures (298-398 K). The application of hydrostatic pressure was observed to induce anti-ferroelectric like double hysteresis loops. This in turn enhances the piezoelectric, energy storage, energy harvesting, and electrocaloric effects. The hydrostatic piezoelectric coefficient (dh) was increased from 50 pCN-1 (0 MPa) to ˜900 pC N-1 (265 MPa) and ˜3200 pCN-1 (330 MPa) at 298 K. Energy storage density was observed to improve by more than 4 times under pressure, in the whole temperature range. The relative change in entropy was also observed to shift from ˜0 to 4.8 J kg-1 K-1 under an applied pressure of 325 MPa. This behavior can be attributed to the evolution of pinched hysteresis loops that have been explained using a phenomenological model. All values represent an improvement of several hundred percent compared to unbiased performance, indicating the potential benefits of the proposed methodology.

  9. Rectangular Shell Plating Under Uniformly Distributed Hydrostatic Pressure

    Science.gov (United States)

    Neubert, M; Sommer, A

    1940-01-01

    A check of the calculation methods used by Foppl and Henky for investigating the reliability of shell plating under hydrostatic pressure has proved that the formulas yield practical results within the elastic range of the material. Foppl's approximate calculation leaves one on the safe side. It further was found on the basis of the marked ductility of the shell plating under tensile stress that the strength is from 50 to 100 percent higher in the elastic range than expected by either method.

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

    Science.gov (United States)

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

    2011-11-16

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

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

    International Nuclear Information System (INIS)

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

    2011-01-01

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

  12. 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.

  13. The difference in endolymphatic hydrostatic pressure elevation induced by isoproterenol between the ampulla and the cochlea.

    Science.gov (United States)

    Inamoto, Ryuhei; Miyashita, Takenori; Matsubara, Ai; Hoshikawa, Hiroshi; Mori, Nozomu

    2017-06-01

    The purpose of the study was to investigate the difference in the responses of endolymphatic hydrostatic pressure to isoproterenol, β-adrenergic receptor agonist, between pars superior and pars inferior. The hydrostatic pressure of endolymph and perilymph and endolymphatic potential in the ampulla and the cochlea during the intravenous administration of isoproterenol were recorded using a servo-null system in guinea pigs. The hydrostatic pressure of endolymph and perilymph in the ampulla and cochlea was similar in magnitude. Isoproterenol significantly increased hydrostatic pressure of ampullar and cochlear endolymph and perilymph with no change in the ampullar endolymphatic potential and endocochlear potential, respectively. The isoproterenol-induced maximum change of endolymphatic hydrostatic pressure in ampulla was significantly (phydrostatic pressure in the ampulla disappeared like that in the cochlea. Isoproterenol elevates endolymphatic hydrostatic pressure in different manner between the vestibule and the cochlea. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  14. Ultra-precision bearings

    CERN Document Server

    Wardle, F

    2015-01-01

    Ultra-precision bearings can achieve extreme accuracy of rotation, making them ideal for use in numerous applications across a variety of fields, including hard disk drives, roundness measuring machines and optical scanners. Ultraprecision Bearings provides a detailed review of the different types of bearing and their properties, as well as an analysis of the factors that influence motion error, stiffness and damping. Following an introduction to basic principles of motion error, each chapter of the book is then devoted to the basic principles and properties of a specific type of bearin

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

    Science.gov (United States)

    2016-12-01

    ARL-TR-7901 ● DEC 2016 US Army Research Laboratory Hydrostatic Compression of 2,4,6,8,10,12- hexanitrohexaaza-isowurtzitane (CL20... Hydrostatic Compression of 2,4,6,8,10,12- hexanitrohexaaza-isowurtzitane (CL20) Co-Crystals by DeCarlos Taylor Weapons and Materials...Technical Report 3. DATES COVERED (From - To) October 2015–September 2016 4. TITLE AND SUBTITLE Hydrostatic Compression of 2,4,6,8,10,12

  16. Hydrostatic control system for the height position of the JINR synchrotron

    International Nuclear Information System (INIS)

    Vasyutinskij, I.Yu.; Zinov'ev, L.P.; Karpov, I.I.

    1978-01-01

    Hydrostatic system with remote read-out is created for a more operative control of height position of synchrocyclotrone electromagnet. 3 hydrostatic heads with electrocontact registration of liquid level position were mounted on every electromagnet quadrant. The heads are placed under the magnet in centers of survey channel of the foundation and are switched on in series. Teh schemes of the main system units are given. The order of assembling and adjustment of hydrostatic system elements of the accelerator is described

  17. Induction of Shiga Toxin-Converting Prophage in Escherichia coli by High Hydrostatic Pressure

    OpenAIRE

    Aertsen, Abram; Faster, David; Michiels, Chris W.

    2005-01-01

    Since high hydrostatic pressure is becoming increasingly important in modern food preservation, its potential effects on microorganisms need to be thoroughly investigated. In this context, mild pressures (

  18. Roller bearing geometry design

    Science.gov (United States)

    Savage, M.; Pinkston, B. H. W.

    1976-01-01

    A theory of kinematic stabilization of rolling cylinders is extended and applied to the design of cylindrical roller bearings. The kinematic stabilization mechanism puts a reverse skew into the rolling elements by changing the roller taper. Twelve basic bearing modification designs are identified amd modeled. Four have single transverse convex curvature in their rollers while eight have rollers which have compound transverse curvature made up of a central cylindrical band surrounded by symmetric bands with slope and transverse curvature. The bearing designs are modeled for restoring torque per unit axial displacement, contact stress capacity, and contact area including dynamic loading, misalignment sensitivity and roller proportion. Design programs are available which size the single transverse curvature roller designs for a series of roller slopes and load separations and which design the compound roller bearings for a series of slopes and transverse radii of curvature. The compound rollers are proportioned to have equal contact stresses and minimum size. Design examples are also given.

  19. DW_BEAR

    Data.gov (United States)

    Department of Homeland Security — Subset of BEAR (Bi-Weekly Examination Analysis and Reporting) data used for financial audit remediation reporting within the Coast Guard Business Intelligence (CGBI)...

  20. Rolling bearing analysis

    CERN Document Server

    Harris, Tedric A

    2001-01-01

    One of the most well-known experts in the field brings cutting-edge research to practitioners in the new edition of this important reference. Covers the improved mathematical calculations for rolling bearing endurance developed by the American Society of Mechanical Engineers and the Society of Lubrication and Tribology Engineers. Updated with new material on Condition-Based Maintenance, new testing methods, and new bearing materials.

  1. Gear bearing drive

    Science.gov (United States)

    Mavroidis, Constantinos (Inventor); Vranish, John M. (Inventor); Weinberg, Brian (Inventor)

    2011-01-01

    A gear bearing drive provides a compact mechanism that operates as an actuator providing torque and as a joint providing support. The drive includes a gear arrangement integrating an external rotor DC motor within a sun gear. Locking surfaces maintain the components of the drive in alignment and provide support for axial loads and moments. The gear bearing drive has a variety of applications, including as a joint in robotic arms and prosthetic limbs.

  2. Load responsive hydrodynamic bearing

    Science.gov (United States)

    Kalsi, Manmohan S.; Somogyi, Dezso; Dietle, Lannie L.

    2002-01-01

    A load responsive hydrodynamic bearing is provided in the form of a thrust bearing or journal bearing for supporting, guiding and lubricating a relatively rotatable member to minimize wear thereof responsive to relative rotation under severe load. In the space between spaced relatively rotatable members and in the presence of a liquid or grease lubricant, one or more continuous ring shaped integral generally circular bearing bodies each define at least one dynamic surface and a plurality of support regions. Each of the support regions defines a static surface which is oriented in generally opposed relation with the dynamic surface for contact with one of the relatively rotatable members. A plurality of flexing regions are defined by the generally circular body of the bearing and are integral with and located between adjacent support regions. Each of the flexing regions has a first beam-like element being connected by an integral flexible hinge with one of the support regions and a second beam-like element having an integral flexible hinge connection with an adjacent support region. A least one local weakening geometry of the flexing region is located intermediate the first and second beam-like elements. In response to application of load from one of the relatively rotatable elements to the bearing, the beam-like elements and the local weakening geometry become flexed, causing the dynamic surface to deform and establish a hydrodynamic geometry for wedging lubricant into the dynamic interface.

  3. HIGH HYDROSTATIC PRESSURE SYSTEMS USE IN FOOD INDUSTRY

    Directory of Open Access Journals (Sweden)

    Yahya TÜLEK

    2006-02-01

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

  4. Hydrostatic pressure dependence of elastic constants for lead fluoride crystal

    International Nuclear Information System (INIS)

    Singh, R.K.; Rao, C.N.

    1988-10-01

    The variations of the second order elastic constants (SOEC) and longitudinal and shear moduli with hydrostatic pressure for the lead fluoride have been investigated theoretically, for the first time, by means of a three-body force potential (TBP) model. The significance of three-body interactions (TBI) has been clearly demonstrated in these investigations. The present TBP model has reproduced the pressure derivatives of the SOEC of PbF more satisfactorily than the shell model and other model calculations. (author). 24 refs, 3 figs, 2 tabs

  5. High hydrostatic pressure in cancer immunotherapy and biomedicine.

    Science.gov (United States)

    Adkins, Irena; Hradilova, Nada; Palata, Ondrej; Sadilkova, Lenka; Palova-Jelinkova, Lenka; Spisek, Radek

    High hydrostatic pressure (HHP) has been known to affect biological systems for >100 years. In this review, we describe the technology of HHP and its effect macromolecules and physiology of eukaryotic cells. We discuss the use of HHP in cancer immunotherapy to kill tumor cells for generation of whole cell and dendritic cell-based vaccines. We further summarize the current use and perspectives of HHP application in biomedicine, specifically in orthopedic surgery and for the viral, microbial and protozoan inactivation to develop vaccines against infectious diseases. Copyright © 2018. Published by Elsevier Inc.

  6. Hydrostatic extrusion of Cu-Ag melt spun ribbon

    Science.gov (United States)

    Hill, Mary Ann; Bingert, John F.; Bingert, Sherri A.; Thoma, Dan J.

    1998-01-01

    The present invention provides a method of producing high-strength and high-conductance copper and silver materials comprising the steps of combining a predetermined ratio of the copper with the silver to produce a composite material, and melt spinning the composite material to produce a ribbon of copper and silver. The ribbon of copper and silver is heated in a hydrogen atmosphere, and thereafter die pressed into a slug. The slug then is placed into a high-purity copper vessel and the vessel is sealed with an electron beam. The vessel and slug then are extruded into wire form using a cold hydrostatic extrusion process.

  7. 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...... by HHP treatment was investigated in different holding media with or without Ca(2+). The efficiency of activation was tested at different pressure levels and media including T2 (HEPES-buffered TCM-199 containing 2% cattle serum), and mannitol-PVA fusion medium with (MPVA + Ca(2+)) or without Ca(2...

  8. Climate Drives Polar Bear Origins

    Science.gov (United States)

    In their provocative analysis of northern bears (“Nuclear genomic sequences reveal that polar bears are an old and distinct bear lineage,” Reports, 20 April, p. 344), F. Hailer et al. use independent nuclear loci to show that polar bears originated during the middle Pleistocene, rather than during t...

  9. Watchable Wildlife: The Black Bear

    Science.gov (United States)

    Lynn L. Rogers

    1992-01-01

    Black bears are the bears people most often encounter. Black bears live in forests over much of North America, unlike grizzlies that live only in Alaska, northern and western Canada, and the northern Rocky Mountains. This brochure presents the latest information on black bear life and how this species responds to an ever-increasing number of campers, hikers, and...

  10. Tribology of alternative bearings.

    Science.gov (United States)

    Fisher, John; Jin, Zhongmin; Tipper, Joanne; Stone, Martin; Ingham, Eileen

    2006-12-01

    The tribological performance and biological activity of the wear debris produced has been compared for highly cross-linked polyethylene, ceramic-on-ceramic, metal-on-metal, and modified metal bearings in a series of in vitro studies from a single laboratory. The functional lifetime demand of young and active patients is 10-fold greater than the estimated functional lifetime of traditional polyethylene. There is considerable interest in using larger diameter heads in these high demand patients. Highly cross-linked polyethylene show a four-fold reduction in functional biological activity. Ceramic-on-ceramic bearings have the lowest wear rates and least reactive wear debris. The functional biological activity is 20-fold lower than with highly cross-linked polyethylene. Hence, ceramic-on-ceramic bearings address the tribological lifetime demand of highly active patients. Metal-on-metal bearings have substantially lower wear rates than highly cross-linked polyethylene and wear decreases with head diameter. Bedding in wear is also lower with reduced radial clearance. Differential hardness ceramic-on-metal bearings and the application of ceramic-like coatings reduce metal wear and ion levels.

  11. Actively lubricated bearings applied as calibrated shakers to aid parameter identification in rotordynamics

    DEFF Research Database (Denmark)

    Santos, Ilmar; Cerda Varela, Alejandro Javier

    2013-01-01

    The servo valve input signal and the radial injection pressure are the two main parameters responsible for dynamically modifying the journal oil film pressure and generating active fluid film forces in controllable fluid film bearings. Such fluid film forces, resulting from a strong coupling...... domain and the application of such a controllable bearing as a calibrated shaker aiming at determining the frequency response function (FRF) of rotordynamic systems; b) experimental quantification of the influence of the supply pressure and servo valve input signal on the FRF of rotor-journal bearing...... between hydrodynamic, hydrostatic and controllable lubrication regimes, can be used either to control or to excite rotor lateral vibrations. An accurate characterization of the active oil film forces is of fundamental importance to elucidate the feasibility of applying the active lubrication as non...

  12. Hydrostatic limits of Fluorinert liquids used for neutron and transport studies at high pressure

    International Nuclear Information System (INIS)

    Sidorov, V A; Sadykov, R A

    2005-01-01

    We determined the hydrostatic limits at room temperature for a number of Fluorinert liquids: FC70, FC75, FC77, FC84, FC87 and their mixtures. Pressure exceeding this limit produces pressure gradients in the sample, which are retained at low temperature. The maximum hydrostatic limit (2.3 GPa) was found for a (1:1) mixture of FC84/87

  13. ERK activation is required for hydrostatic pressure induced-tensile changes in engineered articular cartilage

    Science.gov (United States)

    DuRaine, G D; Athanasiou, K A

    2015-01-01

    The objective of this study was to identify the ERK 1/2 involvement in the changes in compressive and tensile mechanical properties associated with hydrostatic pressure treatment of self-assembled cartilage constructs. In study 1, ERK 1/2 phosphorylation was detected by immunoblot following application of hydrostatic pressure (1 hour of static 10MPa) applied at day 10-14 of self-assembly culture. In study 2, ERK 1/2 activation was blocked during hydrostatic pressure application on days 10-14. With pharmacological inhibition of the ERK pathway by the MEK1/ERK inhibitor U0126 during hydrostatic pressure application on days 10-14, the increase in Young’s modulus induced by hydrostatic pressure was blocked. Furthermore, this reduction in Young’s modulus with U0126 treatment during hydrostatic pressure application corresponded with a decrease in total collagen expression. However, U0126 did not inhibit the increase in aggregate modulus or GAG induced by hydrostatic pressure. These findings demonstrate a link between hydrostatic pressure application, ERK signaling, and changes in biomechanical properties of a tissue engineered construct. PMID:23255524

  14. 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

    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

  15. 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 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.

  16. 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...

  17. EVOLUTION OF THE MERGER-INDUCED HYDROSTATIC MASS BIAS IN GALAXY CLUSTERS

    International Nuclear Information System (INIS)

    Nelson, Kaylea; Nagai, Daisuke; Rudd, Douglas H.; Shaw, Laurie

    2012-01-01

    In this work, we examine the effects of mergers on the hydrostatic mass estimate of galaxy clusters using high-resolution Eulerian cosmological simulations. We utilize merger trees to isolate the last merger for each cluster in our sample and follow the time evolution of the hydrostatic mass bias as the systems relax. We find that during a merger, a shock propagates outward from the parent cluster, resulting in an overestimate in the hydrostatic mass bias. After the merger, as a cluster relaxes, the bias in hydrostatic mass estimate decreases but remains at a level of –5%-10% with 15%-20% scatter within r 500 . We also investigate the post-merger evolution of the pressure support from bulk motions, a dominant cause of this residual mass bias. At r 500 , the contribution from random motions peaks at 30% of the total pressure during the merger and quickly decays to ∼10%-15% as a cluster relaxes. Additionally, we use a measure of the random motion pressure to correct the hydrostatic mass estimate. We discover that 4 Gyr after mergers, the direct effects of the merger event on the hydrostatic mass bias have become negligible. Thereafter, the mass bias is primarily due to residual bulk motions in the gas which are not accounted for in the hydrostatic equilibrium equation. We present a hydrostatic mass bias correction method that can recover the unbiased cluster mass for relaxed clusters with 9% scatter at r 500 and 11% scatter in the outskirts, within r 200 .

  18. The tensile deformation behavior of nuclear-grade isotropic graphite posterior to hydrostatic loading

    International Nuclear Information System (INIS)

    Yoda, S.; Eto, M.

    1983-01-01

    The effects of prehydrostatic loading on microstructural changes and tensile deformation behavior of nuclear-grade isotropic graphite have been examined. Scanning electron micrographs show that formation of microcracks associated with delamination between basal planes occurs under hydrostatic loading. Hydrostatic loading on specimens results in the decrease in tensile strength and increase in residual strain generated by the applied tensile stress at various levels, indicating that the graphite material is weakened by hydrostatic loading. A relationship between residual strain and applied tensile stress for graphite hydrostatically-loaded at several pressure levels can be approximately expressed as element of= (AP + B) sigmasup(n) over a wide range hydrostatic pressure, where element of, P and sigma denote residual strain, hydrostatic pressure and applied tensile stress, respectively; A, B and n are constant. The effects of prehydrostatic loading on the tensile stress-strain behavior of the graphite were examined in more detail. The ratio of stress after hydrostatic loading to that before hydrostatic loading on the stress-strain relationship remains almost unchanged irrespective of strain. (orig.)

  19. ERK activation is required for hydrostatic pressure-induced tensile changes in engineered articular cartilage.

    Science.gov (United States)

    DuRaine, G D; Athanasiou, K A

    2015-04-01

    The objective of this study was to identify ERK 1/2 involvement in the changes in compressive and tensile mechanical properties associated with hydrostatic pressure treatment of self-assembled cartilage constructs. In study 1, ERK 1/2 phosphorylation was detected by immunoblot, following application of hydrostatic pressure (1 h of static 10 MPa) applied at days 10-14 of self-assembly culture. In study 2, ERK 1/2 activation was blocked during hydrostatic pressure application on days 10-14. With pharmacological inhibition of the ERK pathway by the MEK1/ERK inhibitor U0126 during hydrostatic pressure application on days 10-14, the increase in Young's modulus induced by hydrostatic pressure was blocked. Furthermore, this reduction in Young's modulus with U0126 treatment during hydrostatic pressure application corresponded to a decrease in total collagen expression. However, U0126 did not inhibit the increase in aggregate modulus or GAG induced by hydrostatic pressure. These findings demonstrate a link between hydrostatic pressure application, ERK signalling and changes in the biomechanical properties of a tissue-engineered construct. Copyright © 2012 John Wiley & Sons, Ltd.

  20. Partial tooth gear bearings

    Science.gov (United States)

    Vranish, John M. (Inventor)

    2010-01-01

    A partial gear bearing including an upper half, comprising peak partial teeth, and a lower, or bottom, half, comprising valley partial teeth. The upper half also has an integrated roller section between each of the peak partial teeth with a radius equal to the gear pitch radius of the radially outwardly extending peak partial teeth. Conversely, the lower half has an integrated roller section between each of the valley half teeth with a radius also equal to the gear pitch radius of the peak partial teeth. The valley partial teeth extend radially inwardly from its roller section. The peak and valley partial teeth are exactly out of phase with each other, as are the roller sections of the upper and lower halves. Essentially, the end roller bearing of the typical gear bearing has been integrated into the normal gear tooth pattern.

  1. Numerical simulation of alpha-quartz under non-hydrostatic compression. Memory glass and five-coordinated crystalline phases

    OpenAIRE

    Badro, James; Barrat, Jean-Louis; Gillet, Philippe

    1996-01-01

    The behavior of $\\alpha$-quartz under hydrostatic and non-hydrostatic high-pressure conditions has been investigated in Molecular Dynamics simulations of silica in order to clarify the role of non-hydrostatic stresses in the amorphization process. It is shown that the amorphization threshold is not modified if the stress along the {\\bf c} direction is lowered, so that the mean amorphization pressure can effectively be lowered under non-hydrostatic conditions. On the other hand, the applicatio...

  2. Influence of hydrostatic pressure on nuclear radiation detector's properties based on semiconductor alloy CdZnTe

    International Nuclear Information System (INIS)

    Kutnij, V.E.; Kutnij, D.V.; Rybka, A.V.; Nakonechnyj, D.V.; Babun, A.V.

    2003-01-01

    The influence of hydrostatic pressure on properties of CdZnTe semiconductor detectors (Cd-50,Zn-2,Te-48 mas.%, 5 centre dot 5 centre dot 2 mm) was investigated. Were considered different types of hydrostatic treatment at 100 MPa, second hydrostatic treatment at 100 MPa and 200 MPa. Hydrostatic pressure influence on detectors electric resistance, J-V characteristics and spectrometric parameters was determined

  3. 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.

  4. DX centers in III-V semiconductors under hydrostatic pressure

    International Nuclear Information System (INIS)

    Wolk, J.A.

    1992-11-01

    DX centers are deep level defects found in some III-V semiconductors. They have persistent photoconductivity and large difference between thermal and optical ionization energies. Hydrostatic pressure was used to study microstructure of these defects. A new local vibrational mode (LVM) was observed in hydrostatically stressed, Si-doped GaAs. Corresponding infrared absorption peak is distinct from the Si Ga shallow donor LVM peak, which is the only other LVM peak observed in our samples, and is assigned to the Si DX center. Analysis of the relative intensities of the Si DX LVM and the Si shallow donor LVM peaks, combined with Hall effect and resistivity indicate that the Si DX center is negatively charged. Frequency of this new mode provides clues to the structure of this defect. A pressure induced deep donor level in S-doped InP was also discovered which has the properties of a DX center. Pressure at which the new defect becomes more stable than the shallow donor is 82 kbar. Optical ionization energy and energy dependence of the optical absorption cross section was measured for this new effect. Capture barrier from the conduction band into the DX state were also determined. That DX centers can be formed in InP by pressure suggests that DX states should be common in n-type III-V semiconductors. A method is suggested for predicting under what conditions these defects will be the most stable form of the donor impurity

  5. Glycine Insertion Makes Yellow Fluorescent Protein Sensitive to Hydrostatic Pressure

    Science.gov (United States)

    Watanabe, Tomonobu M.; Imada, Katsumi; Yoshizawa, Keiko; Nishiyama, Masayoshi; Kato, Chiaki; Abe, Fumiyoshi; Morikawa, Takamitsu J.; Kinoshita, Miki; Fujita, Hideaki; Yanagida, Toshio

    2013-01-01

    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. PMID:24014139

  6. Investigation of plastic zones near SCC tips in a pipeline after hydrostatic testing

    International Nuclear Information System (INIS)

    Li Jian; Elboujdaini, M.; Gao, M.; Revie, R.W.

    2008-01-01

    Stress corrosion cracking (SCC) is an important failure mechanism for oil and gas pipelines. In the past, hydrostatic testing has been frequently used to assess and mitigate stress corrosion cracking. It is commonly agreed that an effective hydrostatic test not only eliminates critical crack-like flaws, but also blunts the sub-critical crack tip thereby suppressing further SCC propagation. However, little study has been done on the plastic deformation that results from the high stress intensity at the crack tip due to hydrostatic testing pressure and its possible role in subsequent SCC propagation. In this study, microstructural details were examined of an API 5L X52 SCC-containing pipe removed from field service. Plastic deformation generated by the hydrostatic testing pressure was revealed by using high-resolution imaging of a focused ion beam (FIB) microscope. The existence of the microscopic plastic zones around some crack tips suggests that caution should be taken when setting up pipeline hydrostatic tests

  7. Investigation of plastic zones near SCC tips in a pipeline after hydrostatic testing

    Energy Technology Data Exchange (ETDEWEB)

    Li Jian [Materials Technology Laboratory, Natural Resources Canada, 568 Booth Street, Ottawa, Ont., K1A 0G1 (Canada)], E-mail: jili@nrcan.gc.ca; Elboujdaini, M [Materials Technology Laboratory, Natural Resources Canada, 568 Booth Street, Ottawa, Ont., K1A 0G1 (Canada); Gao, M [Blade Energy Partners, 16225 Park Ten Place, Suite 450, Houston, TX 77084 (United States); Revie, R W [Materials Technology Laboratory, Natural Resources Canada, 568 Booth Street, Ottawa, Ont., K1A 0G1 (Canada)

    2008-07-15

    Stress corrosion cracking (SCC) is an important failure mechanism for oil and gas pipelines. In the past, hydrostatic testing has been frequently used to assess and mitigate stress corrosion cracking. It is commonly agreed that an effective hydrostatic test not only eliminates critical crack-like flaws, but also blunts the sub-critical crack tip thereby suppressing further SCC propagation. However, little study has been done on the plastic deformation that results from the high stress intensity at the crack tip due to hydrostatic testing pressure and its possible role in subsequent SCC propagation. In this study, microstructural details were examined of an API 5L X52 SCC-containing pipe removed from field service. Plastic deformation generated by the hydrostatic testing pressure was revealed by using high-resolution imaging of a focused ion beam (FIB) microscope. The existence of the microscopic plastic zones around some crack tips suggests that caution should be taken when setting up pipeline hydrostatic tests.

  8. NON-COHESIVE SOIL DIRECT SHEAR STRENGTH AFFECTED WITH HYDROSTATIC PRESSURE

    Directory of Open Access Journals (Sweden)

    Tadas Tamošiūnas

    2017-12-01

    Full Text Available This paper presents first results of non­cohesive soil direct shear tests with hydrostatic pressure. To reach this aim, it was chosen the Baltic Sea Klaipėda sand, due to granulometry composition and particles shape. According to this, investigated Baltic Sea sand can be called Lithuanian standard sand for scientific testing. Analysis of results revealed, that when it is increased hydrostatic pressure, the shearing strength is also increasing. Comparing air­ dry sand results with fully saturated sand and affected with 100 kPa of hydrostatic pressure, the angle of internal friction increased for 21,24%. Meanwhile, the cohesion was not changing so dramatically according to hydrostatic pressure change. Obtained results allows to proceed this research work more detailed with different loading types, testing procedures and hydrostatic pressures.

  9. Metabolic costs imposed by hydrostatic pressure constrain bathymetric range in the lithodid crab Lithodes maja.

    Science.gov (United States)

    Brown, Alastair; Thatje, Sven; Morris, James P; Oliphant, Andrew; Morgan, Elizabeth A; Hauton, Chris; Jones, Daniel O B; Pond, David W

    2017-11-01

    The changing climate is shifting the distributions of marine species, yet the potential for shifts in depth distributions is virtually unexplored. Hydrostatic pressure is proposed to contribute to a physiological bottleneck constraining depth range extension in shallow-water taxa. However, bathymetric limitation by hydrostatic pressure remains undemonstrated, and the mechanism limiting hyperbaric tolerance remains hypothetical. Here, we assess the effects of hydrostatic pressure in the lithodid crab Lithodes maja (bathymetric range 4-790 m depth, approximately equivalent to 0.1 to 7.9 MPa hydrostatic pressure). Heart rate decreased with increasing hydrostatic pressure, and was significantly lower at ≥10.0 MPa than at 0.1 MPa. Oxygen consumption increased with increasing hydrostatic pressure to 12.5 MPa, before decreasing as hydrostatic pressure increased to 20.0 MPa; oxygen consumption was significantly higher at 7.5-17.5 MPa than at 0.1 MPa. Increases in expression of genes associated with neurotransmission, metabolism and stress were observed between 7.5 and 12.5 MPa. We suggest that hyperbaric tolerance in L maja may be oxygen-limited by hyperbaric effects on heart rate and metabolic rate, but that L maja 's bathymetric range is limited by metabolic costs imposed by the effects of high hydrostatic pressure. These results advocate including hydrostatic pressure in a complex model of environmental tolerance, where energy limitation constrains biogeographic range, and facilitate the incorporation of hydrostatic pressure into the broader metabolic framework for ecology and evolution. Such an approach is crucial for accurately projecting biogeographic responses to changing climate, and for understanding the ecology and evolution of life at depth. © 2017. Published by The Company of Biologists Ltd.

  10. Magnetically leviated superconducting bearing

    Science.gov (United States)

    Weinberger, Bernard R.; Lynds, Jr., Lahmer

    1993-01-01

    A magnetically levitated superconducting bearing includes a magnet (2) mounted on a shaft (12) that is rotatable around an axis of rotation and a Type II superconductor (6) supported on a stator (14) in proximity to the magnet (2). The superconductor (6) is positioned so that when it is cooled to its superconducting state in the presence of a magnetic field, it interacts with the magnet (2) to produce an attractive force that levitates the magnet (2) and supports a load on the shaft (12). The interaction between the superconductor (6) and magnet(2) also produces surface screening currents (8) that generate a repulsive force perpendicular to the load. The bearing also has means for maintaining the superconductor at a temperature below its critical temperature (16, 18). The bearing could also be constructed so the magnet (2) is supported on the stator (14) and the superconductor (6) is mounted on the shaft (12). The bearing can be operated by cooling the superconductor (6) to its superconducting state in the presence of a magnetic field.

  11. Dynamic Culturing of Cartilage Tissue: The Significance of Hydrostatic Pressure

    Science.gov (United States)

    Pereira, Ana L.; Duarte, Ana R.C.; Frias, Ana M.; Pedro, Adriano J.; Oliveira, João T.; Sousa, Rui A.; Reis, Rui L.

    2012-01-01

    Human articular cartilage functions under a wide range of mechanical loads in synovial joints, where hydrostatic pressure (HP) is the prevalent actuating force. We hypothesized that the formation of engineered cartilage can be augmented by applying such physiologic stimuli to chondrogenic cells or stem cells, cultured in hydrogels, using custom-designed HP bioreactors. To test this hypothesis, we investigated the effects of distinct HP regimens on cartilage formation in vitro by either human nasal chondrocytes (HNCs) or human adipose stem cells (hASCs) encapsulated in gellan gum (GG) hydrogels. To this end, we varied the frequency of low HP, by applying pulsatile hydrostatic pressure or a steady hydrostatic pressure load to HNC-GG constructs over a period of 3 weeks, and evaluated their effects on cartilage tissue-engineering outcomes. HNCs (10×106 cells/mL) were encapsulated in GG hydrogels (1.5%) and cultured in a chondrogenic medium under three regimens for 3 weeks: (1) 0.4 MPa Pulsatile HP; (2) 0.4 MPa Steady HP; and (3) Static. Subsequently, we applied the pulsatile regimen to hASC-GG constructs and varied the amplitude of loading, by generating both low (0.4 MPa) and physiologic (5 MPa) HP levels. hASCs (10×106 cells/mL) were encapsulated in GG hydrogels (1.5%) and cultured in a chondrogenic medium under three regimens for 4 weeks: (1) 0.4 MPa Pulsatile HP; (2) 5 MPa Pulsatile HP; and (3) Static. In the HNC study, the best tissue development was achieved by the pulsatile HP regimen, whereas in the hASC study, greater chondrogenic differentiation and matrix deposition were obtained for physiologic loading, as evidenced by gene expression of aggrecan, collagen type II, and sox-9; metachromatic staining of cartilage extracellular matrix; and immunolocalization of collagens. We thus propose that both HNCs and hASCs detect and respond to physical forces, thus resembling joint loading, by enhancing cartilage tissue development in a frequency- and

  12. Biomechanical and immunohistochemical analysis of high hydrostatic pressure-treated Achilles tendons

    International Nuclear Information System (INIS)

    Diehl, P.; Steinhauser, E.; Gollwitzer, H.; Heister, C.; Schauwecker, J.; Schmitt, M.; Milz, S.; Mittelmeier, W.

    2006-01-01

    Reconstruction of bone defects caused by malignant tumors is carried out in different ways. At present, tumor-bearing bone segments are devitalized mainly by extracorporeal irradiation or autoclaving, but both methods have substantial disadvantages. In this regard, high hydrostatic pressure (HHP) treatment of the bone is a new, advancing technology that has been used in preclinical testing to inactivate normal cells and tumor cells without altering the biomechanical properties of the bone. The aim of this study was to examine the biomechanical and immunohistochemical properties of tendons after exposure to HHP and to evaluate whether preservation of the bony attachment of tendons and ligaments is possible. For this, 19 paired Achilles tendons were harvested from both hindlimbs of 4-month-old pigs. After preparation, the cross-sectional area of each tendon was determined by magnetic resonance imaging (MRI). For each animal, one of the two tendons was taken at random and exposed to a pressure of 300 MPa (n=9) or 600 MPa (n=10). The contralateral tendon served as an untreated control. The biomechanical properties of the tendons remained unchanged with respect to the tested parameters: Young's modulus (MPa) and tensile strength (MPa). This finding is in line with immunohistochemical labeling results, as no difference in the labeling pattern of collagen I and versican was observed when comparing the HHP group (at 600 MPa) to the untreated control group. We anticipate that during orthopedic surgery HHP can serve as a novel, promising methodical approach to inactivate Achilles tendon and bone cells without altering the biomechanical properties of the tendons. This should allow one to preserve the attachment of tendon and ligaments to the devitalized bone and to facilitate functional reconstruction. (author)

  13. Colorectal perforation by self-induced hydrostatic pressure: a report of two cases.

    Science.gov (United States)

    Choi, Pyong Wha

    2013-02-01

    Most iatrogenic colorectal perforations occur as a result of endoscopic or fluoroscopic studies. Accidents associated with hydrostatic pressure-induced perforation are rarely reported, and self-induced hydrostatic pressure is an extremely rare cause of perforation because the anal sphincter complex may provide a protective barrier against perianal hydrostatic pressure. We present two cases of rectosigmoid colon perforation secondary to self-induced hydrostatic pressure. A 61-year-old man and a 45-year-old man presented with abdominal pain after forceful entry of tap water into the rectum, during rinsing of the anus after defecation in the first case, and during self-administered enema in the second case. Emergency operations were performed with the suspicion of hydrostatic pressure-induced rectal injury, and showed rectosigmoid mesenteric perforation in both cases. Resection of the diseased segment and end colostomy (Hartmann's procedure) was performed in the first case, and primary resection and anastomosis in the second case. The pathologic results showed abrupt loss of the colonic wall in the mesenteric border, without evidence of other inflammatory disease; these findings were consistent with acute mechanical colon injury. The postoperative course in both cases was uneventful. These cases put forth an unusual type of colorectal injury, caused specifically by hydrostatic pressure, thus adding to the available literature on hydrostatic pressure-induced injury. Copyright © 2013 Elsevier Inc. All rights reserved.

  14. Hydrostatic pressure enhances mitomycin C induced apoptosis in urothelial carcinoma cells.

    Science.gov (United States)

    Chen, Shao-Kuan; Chung, Chih-Ang; Cheng, Yu-Che; Huang, Chi-Jung; Ruaan, Ruoh-Chyu; Chen, Wen-Yih; Li, Chuan; Tsao, Chia-Wen; Hu, Wei-Wen; Chien, Chih-Cheng

    2014-01-01

    Urothelial carcinoma (UC) of the bladder is the second most common cancer of the genitourinary system. Clinical UC treatment usually involves transurethral resection of the bladder tumor followed by adjuvant intravesical immunotherapy or chemotherapy to prevent recurrence. Intravesical chemotherapy induces fewer side effects than immunotherapy but is less effective at preventing tumor recurrence. Improvement to intravesical chemotherapy is, therefore, needed. Cellular effects of mitomycin C (MMC) and hydrostatic pressure on UC BFTC905 cells were assessed. The viability of the UC cells was determined using cellular proliferation assay. Changes in apoptotic function were evaluated by caspase 3/7 activities, expression of FasL, and loss of mitochondrial membrane potential. Reduced cell viability was associated with increasing hydrostatic pressure. Caspase 3/7 activities were increased following treatment of the UC cells with MMC or hydrostatic pressure. In combination with 10 kPa hydrostatic pressure, MMC treatment induced increasing FasL expression. The mitochondria of UC cells displayed increasingly impaired membrane potentials following a combined treatment with 10 μg/ml MMC and 10 kPa hydrostatic pressure. Both MMC and hydrostatic pressure can induce apoptosis in UC cells through an extrinsic pathway. Hydrostatic pressure specifically increases MMC-induced apoptosis and might minimize the side effects of the chemotherapy by reducing the concentration of the chemical agent. This study provides a new and alternative approach for treatment of patients with UC following transurethral resection of the bladder tumor. Copyright © 2014 Elsevier Inc. All rights reserved.

  15. 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 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....... 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...

  16. 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.

  17. Transport properties in GaTe under hydrostatic pressure

    International Nuclear Information System (INIS)

    Gouskov, L.; Carvalho, M.

    1980-01-01

    First results of the resistivity rho(perpendicular) and rho(parallel)(perpendicular and parallel to the normal to the cleavage plane) under hydrostatic pressure (1 bar <= P <= 3 kbar) on GaTe grown by the Bridgman method, are given and discussed. The analysis of electrical transport properties of GaTe under pressure, indicates a complex nature of the acceptor level in this material. The activation energy Esub(a) has a negative pressure coefficient which is sample dependent. The comparison of the variations of rho(parallel) and rho(perpendicular) versus pressure shows that the activation energy E of the rho(parallel)/rho(perpendicular) ratio has also a negative pressure coefficient which can be justified in the frame of a one-dimensional disorder model proposed by Maschke and Schmid, in order to explain the transport properties in the direction of the normal to the cleavage plane. (author)

  18. 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.

  19. Hydrometer calibration by hydrostatic weighing with automated liquid surface positioning

    International Nuclear Information System (INIS)

    Aguilera, Jesus; Wright, John D; Bean, Vern E

    2008-01-01

    We describe an automated apparatus for calibrating hydrometers by hydrostatic weighing (Cuckow's method) in tridecane, a liquid of known, stable density, and with a relatively low surface tension and contact angle against glass. The apparatus uses a laser light sheet and a laser power meter to position the tridecane surface at the hydrometer scale mark to be calibrated with an uncertainty of 0.08 mm. The calibration results have an expanded uncertainty (with a coverage factor of 2) of 100 parts in 10 6 or less of the liquid density. We validated the apparatus by comparisons using water, toluene, tridecane and trichloroethylene, and found agreement within 40 parts in 10 6 or less. The new calibration method is consistent with earlier, manual calibrations performed by NIST. When customers use calibrated hydrometers, they may encounter uncertainties of 370 parts in 10 6 or larger due to surface tension, contact angle and temperature effects

  20. Hydrometer calibration by hydrostatic weighing with automated liquid surface positioning

    Science.gov (United States)

    Aguilera, Jesus; Wright, John D.; Bean, Vern E.

    2008-01-01

    We describe an automated apparatus for calibrating hydrometers by hydrostatic weighing (Cuckow's method) in tridecane, a liquid of known, stable density, and with a relatively low surface tension and contact angle against glass. The apparatus uses a laser light sheet and a laser power meter to position the tridecane surface at the hydrometer scale mark to be calibrated with an uncertainty of 0.08 mm. The calibration results have an expanded uncertainty (with a coverage factor of 2) of 100 parts in 106 or less of the liquid density. We validated the apparatus by comparisons using water, toluene, tridecane and trichloroethylene, and found agreement within 40 parts in 106 or less. The new calibration method is consistent with earlier, manual calibrations performed by NIST. When customers use calibrated hydrometers, they may encounter uncertainties of 370 parts in 106 or larger due to surface tension, contact angle and temperature effects.

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

    International Nuclear Information System (INIS)

    Zhang Ying; Cao Juexian; 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 sp 2 -to-sp 3 bonding transition, which is confirmed by recent experiments on deformed carbon nanotubes

  2. Variable Ratio Hydrostatic Transmission Simulator for Optimal Wind Power Drivetrains

    Directory of Open Access Journals (Sweden)

    Jose M. Garcia-Bravo

    2017-01-01

    Full Text Available This work presents a hydromechanical transmission coupled to an electric AC motor and DC generator to simulate a wind power turbine drive train. The goal of this project was to demonstrate and simulate the ability of a hydrostatic variable ratio system to produce constant electric power at varying wind speeds. The experimental results show that the system can maintain a constant voltage when a 40% variation in input speed is produced. An accompanying computer simulation of the system was built and experimentally validated showing a discrete error no larger than 12%. Both the simulation and the experimental results show that the electrical power output can be regulated further if an energy storage device is used to absorb voltage spikes produced by abrupt changes in wind speed or wind direction.

  3. Investigating the nucleation of protein crystals with hydrostatic pressure

    International Nuclear Information System (INIS)

    Kadri, A; Damak, M; Jenner, G; Lorber, B; Giege, R

    2003-01-01

    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 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 3 mol -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

  4. 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.

  5. Characterization of high hydrostatic pressure-injured Bacillus subtilis cells.

    Science.gov (United States)

    Inaoka, Takashi; Kimura, Keitarou; Morimatsu, Kazuya; Yamamoto, Kazutaka

    2017-06-01

    High hydrostatic pressure (HHP) affects various cellular processes. Using a sporulation-deficient Bacillus subtilis strain, we characterized the properties of vegetative cells subjected to HHP. When stationary-phase cells were exposed to 250 MPa of HHP for 10 min at 25 °C, approximately 50% of cells were viable, although they exhibited a prolonged growth lag. The HHP-injured cells autolyzed in the presence of NaCl or KCl (at concentrations ≥100 mM). Superoxide dismutase slightly protected the viability of HHP-treated cells, whereas vegetative catalases had no effect. Thus, unlike HHP-injured Escherichia coli, oxidative stress only slightly affected vegetative B. subtilis subjected to HHP.

  6. Impact of high hydrostatic pressure on bacterial proteostasis.

    Science.gov (United States)

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

    2017-12-01

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

  7. Actuators for Active Magnetic Bearings

    Directory of Open Access Journals (Sweden)

    Eric H. Maslen

    2017-10-01

    Full Text Available The literature of active magnetic bearing (AMB technology dates back to at least 1937 when the earliest work that clearly describes an active magnetic bearing system was published by Jesse Beams [...

  8. A general relativistic hydrostatic model for a galaxy

    International Nuclear Information System (INIS)

    Hojman, R.; Pena, L.; Zamorano, N.

    1991-08-01

    The existence of huge amounts of mass laying at the center of some galaxies has been inferred by data gathered at different wavelengths. It seems reasonable then, to incorporate general relativity in the study of these objects. A general relativistic hydrostatic model for a galaxy is studied. We assume that the galaxy is dominated by the dark mass except at the nucleus, where the luminous matter prevails. It considers four different concentric spherically symmetric regions, properly matched and with a specific equation of state for each of them. It yields a slowly raising orbital velocity for a test particle moving in the background gravitational field of the dark matter region. In this sense we think of this model as representing a spiral galaxy. The dependence of the mass on the radius in cluster and field spiral galaxies published recently, can be used to fix the size of the inner luminous core. A vanishing pressure at the edge of the galaxy and the assumption of hydrostatic equilibrium everywhere generates a jump in the density and the orbital velocity at the shell enclosing the galaxy. This is a prediction of this model. The ratio between the size core and the shells introduced here are proportional to their densities. In this sense the model is scale invariant. It can be used to reproduce a galaxy or the central region of a galaxy. We have also compared our results with those obtained with the Newtonian isothermal sphere. The luminosity is not included in our model as an extra variable in the determination of the orbital velocity. (author). 29 refs, 10 figs

  9. Delayed child-bearing.

    Science.gov (United States)

    Johnson, Jo-Ann; Tough, Suzanne

    2012-01-01

    To provide an overview of delayed child-bearing and to describe the implications for women and health care providers. Delayed child-bearing, which has increased greatly in recent decades, is associated with an increased risk of infertility, pregnancy complications, and adverse pregnancy outcome. This guideline provides information that will optimize the counselling and care of Canadian women with respect to their reproductive choices. Maternal age is the most important determinant of fertility, and obstetric and perinatal risks increase with maternal age. Many women are unaware of the success rates or limitations of assisted reproductive technology and of the increased medical risks of delayed child-bearing, including multiple births, preterm delivery, stillbirth, and Caesarean section. This guideline provides a framework to address these issues. Studies published between 2000 and August 2010 were retrieved through searches of PubMed and the Cochrane Library using appropriate key words (delayed child-bearing, deferred pregnancy, maternal age, assisted reproductive technology, infertility, and multiple births) and MeSH terms (maternal age, reproductive behaviour, fertility). The Internet was also searched using similar key words, and national and international medical specialty societies were searched for clinical practice guidelines and position statements. Data were extracted based on the aims, sample, authors, year, and results. The quality of evidence was rated using the criteria described in the Report of the Canadian Task Force on Preventive Health Care (Table 1). The Society of Obstetricians and Gynaecologists of Canada. RECOMMENDATIONS 1. Women who delay child-bearing are at increased risk of infertility. Prospective parents, especially women, should know that their fecundity and fertility begin to decline significantly after 32 years of age. Prospective parents should know that assisted reproductive technologies cannot guarantee a live birth or completely

  10. Government Risk-Bearing

    CERN Document Server

    1993-01-01

    The u.s. government bulks large in the nation's financial markets. The huge volume of government-issued and -sponsored debt affects the pricing and volume ofprivate debt and, consequently, resource allocation between competing alternatives. What is often not fully appreciated is the substantial influence the federal government wields overresource allocation through its provisionofcreditandrisk-bearing services to the private economy. Because peopleand firms generally seekto avoid risk, atsomeprice they are willing to pay another party to assume the risk they would otherwise face. Insurance companies are a class of private-sector firms one commonly thinks of as providing these services. As the federal government has expanded its presence in the U.S. economy during this century, it has increasingly developed programs aimed at bearing risks that the private sector either would not take on at any price, or would take on but atapricethoughtto besogreatthatmostpotentialbeneficiarieswouldnotpurchase the coverage. To...

  11. Passive magnetic bearing system

    Science.gov (United States)

    Post, Richard F.

    2014-09-02

    An axial stabilizer for the rotor of a magnetic bearing provides external control of stiffness through switching in external inductances. External control also allows the stabilizer to become a part of a passive/active magnetic bearing system that requires no external source of power and no position sensor. Stabilizers for displacements transverse to the axis of rotation are provided that require only a single cylindrical Halbach array in its operation, and thus are especially suited for use in high rotation speed applications, such as flywheel energy storage systems. The elimination of the need of an inner cylindrical array solves the difficult mechanical problem of supplying support against centrifugal forces for the magnets of that array. Compensation is provided for the temperature variation of the strength of the magnetic fields of the permanent magnets in the levitating magnet arrays.

  12. Hydrostatic pressure effects on impurity states in InAs/GaAs quantum dot

    International Nuclear Information System (INIS)

    Xia Congxin; Liu Yaming; Wei Shuyi

    2008-01-01

    Within the framework of effective-mass approximation, the hydrostatic pressure effects on the donor binding energy of a hydrogenic impurity in InAs/GaAs self-assembled quantum dot(QD) are investigated by means of a variational method. Numerical results show that the donor binding energy increases when the hydrostatic pressure increases for any impurity position and QD size. Moreover, the hydrostatic pressure has a remarkable influence on the donor binding energy for small QD. Realistic cases, including the impurity in the QD and the surrounding barrier, are considered

  13. X-ray reflectivity measurements of liquid/solid interfaces under high hydrostatic pressure conditions.

    Science.gov (United States)

    Wirkert, Florian J; Paulus, Michael; Nase, Julia; Möller, Johannes; Kujawski, Simon; Sternemann, Christian; Tolan, Metin

    2014-01-01

    A high-pressure cell for in situ X-ray reflectivity measurements of liquid/solid interfaces at hydrostatic pressures up to 500 MPa (5 kbar), a pressure regime that is particularly important for the study of protein unfolding, is presented. The original set-up of this hydrostatic high-pressure cell is discussed and its unique properties are demonstrated by the investigation of pressure-induced adsorption of the protein lysozyme onto hydrophobic silicon wafers. The presented results emphasize the enormous potential of X-ray reflectivity studies under high hydrostatic pressure conditions for the in situ investigation of adsorption phenomena in biological systems.

  14. The temperature control and water quality regulation for steam generator secondary side hydrostatic test

    International Nuclear Information System (INIS)

    Xiao Bo; Liu Dongyong

    2014-01-01

    The secondary side hydrostatic test for the steam generator of M310 unit is to verify the pressure tightness of steam generator secondary side tube sheet and related systems. As for the importance of the steam generator, the water temperature and water quality of hydrostatic test has strict requirements. The discussion on the water temperature control and water quality regulation for the secondary loop hydrostatic test of Fuqing Unit 1 contribute greatly to the guiding work for the preparation of the steam generator pressure test for M310 unit. (authors)

  15. Stacked magnet superconducting bearing

    International Nuclear Information System (INIS)

    Rigney, T.K. II; Saville, M.P.

    1993-01-01

    A superconducting bearing is described, comprising: a plurality of permanent magnets magnetized end-to-end and stacked side-by-side in alternating polarity, such that flux lines flow between ends of adjacent magnets; isolating means, disposed between said adjacent magnets, for reducing flux leakage between opposing sides of said adjacent magnets; and a member made of superconducting material having at least one surface in communication with said flux lines

  16. Radium bearing waste disposal

    International Nuclear Information System (INIS)

    Tope, W.G.; Nixon, D.A.; Smith, M.L.; Stone, T.J.; Vogel, R.A.; Schofield, W.D.

    1995-01-01

    Fernald radium bearing ore residue waste, stored within Silos 1 and 2 (K-65) and Silo 3, will be vitrified for disposal at the Nevada Test Site (NTS). A comprehensive, parametric evaluation of waste form, packaging, and transportation alternatives was completed to identify the most cost-effective approach. The impacts of waste loading, waste form, regulatory requirements, NTS waste acceptance criteria, as-low-as-reasonably-achievable principles, and material handling costs were factored into the recommended approach

  17. Magnetic translator bearings

    Science.gov (United States)

    Hockney, Richard L. (Inventor); Downer, James R. (Inventor); Eisenhaure, David B. (Inventor); Hawkey, Timothy J. (Inventor); Johnson, Bruce G. (Inventor)

    1990-01-01

    A magnetic bearing system for enabling translational motion includes a carriage and a shaft for movably supporting the carriage; a first magnetic bearing fixed to one of the carriage and shaft and slidably received in a first channel of the other of the carriage and shaft. The first channel is generally U shaped with two side walls and a back wall. The magnetic bearing includes a pair of spaced magnetic pole pieces, each pole piece having a pair of electromagnetic coils mounted on poles on opposite ends of the pole piece proximate the side walls, and a third electromagnetic coil mounted on a pole of the pole piece proximate the backwall; a motion sensor for sensing translational motion along two axes and rotationally about three axes of the carriage and shaft relative to each other; and a correction circuit responsive to the sensor for generating a correction signal to drive the coils to compensate for any misalignment sensed between the carriage and the shaft.

  18. Bearing for liquid metal pump

    International Nuclear Information System (INIS)

    Dickinson, R.J.; Pennell, W.E.; Wasko, J.

    1984-01-01

    A liquid metal pump bearing support comprises a series of tangentially oriented spokes that connect the bearing cylinder to the pump internals structure. The spokes may be arranged in a plurality of planes extending from the bearing cylinder to the pump internals with the spokes in one plane being arranged alternately with those in the next plane. The bearing support structure provides the pump with sufficient lateral support for the bearing structure together with the capability of accommodating differential thermal expansion without adversely affecting pump performance

  19. Bearing construction for refrigeration compresssor

    Science.gov (United States)

    Middleton, Marc G.; Nelson, Richard T.

    1988-01-01

    A hermetic refrigeration compressor has a cylinder block and a crankshaft rotatable about a vertical axis to reciprocate a piston in a cylinder on the cylinder block. A separate bearing housing is secured to the central portion of the cylinder block and extends vertically along the crankshaft, where it carries a pair of roller bearings to journal the crankshaft. The crankshaft has a radially extending flange which is journaled by a thrust-type roller bearing above the bearing housing to absorb the vertical forces on the crankshaft so that all three of the roller bearings are between the crankshaft and the bearing housing to maintain and control the close tolerances required by such bearings.

  20. 77 FR 70423 - Black Bear Hydro Partners, LLC and Black Bear Development Holdings, LLC and Black Bear SO, LLC...

    Science.gov (United States)

    2012-11-26

    ... Bear Hydro Partners, LLC and Black Bear Development Holdings, LLC and Black Bear SO, LLC; Notice of..., 2012, Black Bear Hydro Partners, LLC, sole licensee (transferor) and Black Bear Development Holdings, LLC and Black Bear SO, LLC (transferees) filed an application for the partial the transfer of licenses...

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

    International Nuclear Information System (INIS)

    Bonaventura, L.; Cesari, D.

    2005-01-01

    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

  2. Retrogradation of Maize Starch after High Hydrostatic Pressure Gelation: Effect of Amylose Content and Depressurization Rate

    KAUST Repository

    Yang, Zhi; Swedlund, Peter; Gu, Qinfen; Hemar, Yacine; Chaieb, Saharoui

    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

  3. Study of the Energy Conversion Process in the Electro-Hydrostatic Drive of a Vehicle

    Directory of Open Access Journals (Sweden)

    Wiesław Grzesikiewicz

    2018-02-01

    Full Text Available In the paper, we describe a study of an electro-hydrostatic hybrid drive of a utility van intended for city traffic. In this hybrid drive, the electric drive is periodically accompanied by hydrostatic drive, especially during acceleration and regenerative braking of the vehicle. We present a mathematical model of the hybrid drive as a set of dynamics and regulation equations of the van traveling at a given speed. On this basis, we construct a computer program which we use to simulate the processes of energy conversion in the electro-hydrostatic drive. The main goal of the numerical simulation is to assess the possibility of reducing energy intensity of the electric drive through such a support of the hydrostatic drive. The obtained results indicate that it is possible to reduce the load on elements of the electric system and, therefore, improve energy conversion.

  4. Intermittent hydrostatic compressive force stimulates exclusively the proteoglycan synthesis of osteoarthritic human cartilage

    NARCIS (Netherlands)

    Lafeber, F.; Veldhuijzen, J. P.; Vanroy, J. L.; Huber-Bruning, O.; Bijlsma, J. W.

    1992-01-01

    In paired observations the in vitro proteoglycan turnover was studied of human normal and osteoarthritic cartilage in the absence and presence of intermittent hydrostatic compressive force. Shortly after collection, osteoarthritic cartilage showed a higher proteoglycan synthesis rate than normal

  5. High-pressure resistivity technique for quasi-hydrostatic compression experiments.

    Science.gov (United States)

    Rotundu, C R; Ćuk, T; Greene, R L; Shen, Z-X; Hemley, Russell J; Struzhkin, V V

    2013-06-01

    Diamond anvil cell techniques are now well established and powerful methods for measuring materials properties to very high pressure. However, high pressure resistivity measurements are challenging because the electrical contacts attached to the sample have to survive to extreme stress conditions. Until recently, experiments in a diamond anvil cell were mostly limited to non-hydrostatic or quasi-hydrostatic pressure media other than inert gases. We present here a solution to the problem by using focused ion beam ultrathin lithography for a diamond anvil cell loaded with inert gas (Ne) and show typical resistivity data. These ultrathin leads are deposited on the culet of the diamond and are attaching the sample to the anvil mechanically, therefore allowing for measurements in hydrostatic or nearly hydrostatic conditions of pressure using noble gases like Ne or He as pressure transmitting media.

  6. Electric Field Induced Strain in Electrostrictive Polymers Under High Hydrostatic Pressure - System Development and Material Characterization

    National Research Council Canada - National Science Library

    Zhang, Q

    2000-01-01

    ... of (i) developing a high performance piezo-bimorph based dilatometer which can be used to characterize the electric field induced strain response in polymer films under high hydrostatic pressure, (ii...

  7. Development and validation of constitutive equation of HBS irradiation swelling considering hydrostatic pressure

    International Nuclear Information System (INIS)

    Gao Lijun; Jiang Shengyao; Yu Jiyang; Chen Bingde; Xiao Zhong

    2014-01-01

    The mechanism of hydrostatic pressure affecting the irradiation swelling of UO_2 high burnup structure was analyzed. Three basic assumptions used to develop the constitutive equation of irradiation swelling were made accordingly. It is concluded that hydrostatic pressure imposes an important impact on irradiation swelling mainly through compressing the UO_2 high burnup structure pores. Based on the already developed correlation of the irradiation swelling of UO_2 high burnup structure, pore shrinkage due to the application of hydrostatic pressure and thus the reduction of irradiation swelling of UO_2 high burnup structure were determined quantitatively, and the constitutive equation of irradiation swelling of UO_2 high burnup structure considering the hydrostatic pressure was constructed successfully. The constitutive equation is validated using available irradiation swelling data of UO_2 high burnup structure, which demonstrates its reasonability. (authors)

  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. Introgressive hybridization: brown bears as vectors for polar bear alleles.

    Science.gov (United States)

    Hailer, Frank

    2015-03-01

    The dynamics and consequences of introgression can inform about numerous evolutionary processes. Biologists have therefore long been interested in hybridization. One challenge, however, lies in the identification of nonadmixed genotypes that can serve as a baseline for accurate quantification of admixture. In this issue of Molecular Ecology, Cahill et al. (2015) analyse a genomic data set of 28 polar bears, eight brown bears and one American black bear. Polar bear alleles are found to be introgressed into brown bears not only near a previously identified admixture zone on the Alaskan Admiralty, Baranof and Chichagof (ABC) Islands, but also far into the North American mainland. Elegantly contrasting admixture levels at autosomal and X chromosomal markers, Cahill and colleagues infer that male-biased dispersal has spread these introgressed alleles away from the Late Pleistocene contact zone. Compared to a previous study on the ABC Island population in which an Alaskan brown bear served as a putatively admixture-free reference, Cahill et al. (2015) utilize a newly sequenced Swedish brown bear as admixture baseline. This approach reveals that brown bears have been impacted by introgression from polar bears to a larger extent (up to 8.8% of their genome), than previously known, including the bear that had previously served as admixture baseline. No evidence for introgression of brown bear into polar bear is found, which the authors argue could be a consequence of selection. Besides adding new exciting pieces to the puzzle of polar/brown bear evolutionary history, the study by Cahill and colleagues highlights that wildlife genomics is moving from analysing single genomes towards a landscape genomics approach. © 2015 John Wiley & Sons Ltd.

  10. Bulk-Flow Analysis of Hybrid Thrust Bearings for Advanced Cryogenic Turbopumps

    Science.gov (United States)

    SanAndres, Luis

    1998-01-01

    A bulk-flow analysis and computer program for prediction of the static load performance and dynamic force coefficients of angled injection, orifice-compensated hydrostatic/hydrodynamic thrust bearings have been completed. The product of the research is an efficient computational tool for the design of high-speed thrust bearings for cryogenic fluid turbopumps. The study addresses the needs of a growing technology that requires of reliable fluid film bearings to provide the maximum operating life with optimum controllable rotordynamic characteristics at the lowest cost. The motion of a cryogenic fluid on the thin film lands of a thrust bearing is governed by a set of bulk-flow mass and momentum conservation and energy transport equations. Mass flow conservation and a simple model for momentum transport within the hydrostatic bearing recesses are also accounted for. The bulk-flow model includes flow turbulence with fluid inertia advection, Coriolis and centrifugal acceleration effects on the bearing recesses and film lands. The cryogenic fluid properties are obtained from realistic thermophysical equations of state. Turbulent bulk-flow shear parameters are based on Hirs' model with Moody's friction factor equations allowing a simple simulation for machined bearing surface roughness. A perturbation analysis leads to zeroth-order nonlinear equations governing the fluid flow for the thrust bearing operating at a static equilibrium position, and first-order linear equations describing the perturbed fluid flow for small amplitude shaft motions in the axial direction. Numerical solution to the zeroth-order flow field equations renders the bearing flow rate, thrust load, drag torque and power dissipation. Solution to the first-order equations determines the axial stiffness, damping and inertia force coefficients. The computational method uses well established algorithms and generic subprograms available from prior developments. The Fortran9O computer program hydrothrust runs

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

    OpenAIRE

    M. Arici

    2006-01-01

    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 ...

  12. Stability analysis and finite element simulations of superplastic forming in the presence of hydrostatic pressure

    Science.gov (United States)

    Nazzal, M. A.

    2018-04-01

    It is established that some superplastic materials undergo significant cavitation during deformation. In this work, stability analysis for the superplastic copper based alloy Coronze-638 at 550 °C based on Hart's definition of stable plastic deformation and finite element simulations for the balanced biaxial loading case are carried out to study the effects of hydrostatic pressure on cavitation evolution during superplastic forming. The finite element results show that imposing hydrostatic pressure yields to a reduction in cavitation growth.

  13. Preliminary study on the influence of the tides of planet earth on hydrostatic leveling system

    International Nuclear Information System (INIS)

    He Xiaoye; Xu Shaofeng; Wang Peng

    2012-01-01

    Hydrostatic leveling system, used mainly in survey and alignment technology in particle accelerator and monitoring the tides is introduced in this paper. Based on the theory about the ocean tide and earth tide, we analyze effects of the earth tides on a hydrostatic leveling system. From the data obtained from an HLS, and their F are, and finally we verify the influence of the tides of planet earth. (authors)

  14. 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...... strongly on the strain conditions and SL geometry, but weakly on the applied external hydrostatic pressure....

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

    International Nuclear Information System (INIS)

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

    1984-01-01

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

  16. Hydrostatic-pressure induced phase transition of phonons in single-walled nanotubes

    International Nuclear Information System (INIS)

    Feng Peng; Meng Qingchao

    2009-01-01

    We study the effect of the hydrostatic pressure on the phonons in single-walled carbon nanotubes (SWNTs) in a magnetic field. We calculate the magnetic moments of the phonons using a functional integral technique, and find that the phonons in SWNTs undergo a pressure-induced phase transition from the paramagnetic phase to the diamagnetic phase under hydrostatic pressure 2 GPa. We explain the mechanism of generating this phase transition.

  17. Self lubricating fluid bearings

    International Nuclear Information System (INIS)

    Kapich, D.D.

    1980-01-01

    The invention concerns self lubricating fluid bearings, which are used in a shaft sealed system extending two regions. These regions contain fluids, which have to be isolated. A first seal is fluid tight for the first region between the carter shaft and the shaft. The second seal is fluid tight between the carter and the shaft, it communicates with the second region. The first fluid region is the environment surrounding the shaft carter. The second fluid region is a part of a nuclear reactor which contains the cooling fluid. The shaft is conceived to drive a reactor circulating and cooling fluid [fr

  18. Combined use of infrared and Raman spectra in the characterization of orthoclase under various hydrostatic pressures.

    Science.gov (United States)

    Liu, Rui; Wang, Zhi-Hua; Xu, Qiang; Yu, Na; Cao, Miao-Cong

    2014-02-01

    Colorless and pink orthoclase from Balikun granite body, East Zhunger in Xinjiang, served as the samples for the research on hydrostatic pressure experiment. The in-situ hydrostatic pressure test for orthoclases was conducted at the room temperature and pressures from 100 to 600 MPa using cubic zirconia anvil cell, with quartz as pressure gauge. The water located in the orthoclases for the conditions of different hydrostatic pressures was characterized through the methods of Fourier transform infrared (FTIR) and Raman spectra. The results showed that there was a linear correlation between the shifting of Raman bands and hydrostatic pressure applied to the feldspar. All of vibration peaks of M-O structural groups in orthoclases, the bending vibration peaks of Si(Al(IV))-O-Si bond and tetrahedron groups of [SiO4] in Raman spectra shifted toward the higher frequency regularly, the drift distance is 2, 2.19 and less than 2 cm(-1) respectively. The spectra of FTIR suggested that there was more water in colorless orthoclases than the pink one under certain conditions of hydrostatic pressure. The intensity and integral area centered at 3420 cm(-1) in FTIR spectra increased with the rising of hydrostatic pressure. The integral area for colorless and pink feldspar in FTIR spectra rose from 120, 1383 cm(-1) under normal pressure to 1570, 2001 cm(-1) at 600 MPa respectively. The experimental results might indicate that the water in the earth crust could enter the orthoclases in certain condition of the aqueous confining pressure.

  19. Experimental research on dynamic mechanical properties of PZT ceramic under hydrostatic pressure

    International Nuclear Information System (INIS)

    Wang, S.; Liu, K.X.

    2011-01-01

    Highlights: → We developed an experimental device to examine dynamic mechanical properties of PZT. → Ductile behavior of PZT was seen when hydrostatic pressure was involved. → Compressive strength was shown sensitive to hydrostatic pressure and strain-rate. → A failure criterion was suggested to explain the failure behavior of PZT. - Abstract: An experimental technique for initially applied hydrostatic pressure in specimens subjected to axial impact has been developed to study the dynamic mechanical properties of materials. The technique was employed for the purpose of examining the dynamic mechanical properties of lead zirconate titanate (PZT) at zero to 15 MPa hydrostatic pressures. Experimental results unambiguously exhibit the ductile behavior of PZT when hydrostatic pressure is involved. The compressive strength is demonstrated sensitive to the initial hydrostatic pressure and the strain-rate. The fracture modes are analyzed by means of scanning electron microscopy (SEM). Moreover, a failure criterion based on Mohr-Coulomb failure theory is suggested to explain the brittle and ductile failure of PZT.

  20. Involvement of Smad3 pathway in atrial fibrosis induced by elevated hydrostatic pressure.

    Science.gov (United States)

    Wei, Wei; Rao, Fang; Liu, Fangzhou; Xue, Yumei; Deng, Chunyu; Wang, Zhaoyu; Zhu, Jiening; Yang, Hui; Li, Xin; Zhang, Mengzhen; Fu, Yongheng; Zhu, Wensi; Shan, Zhixin; Wu, Shulin

    2018-06-01

    Hypertension is a main risk factor for atrial fibrillation, but the direct effects of hydrostatic pressure on the atrial fibrosis are still unknown. The present study investigated whether hydrostatic pressure is responsible for atrial fibrosis, and addressed a potential role of the Smad pathway in this pathology. Biochemical assays were used to study regulation and expression of fibrotic factors in spontaneously hypertensive rats (SHRs) and Wistar rats, and in cardiac fibroblasts (CFs) cultured under standard (0 mmHg) and elevated (20, 40 mmHg) hydrostatic pressure. Levels of atrial fibrosis and protein expression of fibrotic factors Col-1A1/-3A1, TGF-β1, and MMP-2 in SHRs' left atrial tissues were higher than those in Wistar rats. Exposure to elevated pressure was associated with the proliferation of CFs. The protein expression of Col-1A1/-3A1, TGF-β1, and MMP-2 in CFs was also up-regulated in a pressure-dependent manner. The proliferation of CFs and increased expressions of fibrotic markers induced by elevated hydrostatic pressure could be reversed by the Smad3 inhibitor naringenin. The activation of Smad3 pathway was also stimulated by elevated hydrostatic pressure. These results demonstrate that CF secretory function and proliferation can be up-regulated by exposure to elevated pressure, and that Smad3 may modulate CF activation induced by high hydrostatic pressure. © 2017 Wiley Periodicals, Inc.

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

    Science.gov (United States)

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

    2012-07-01

    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 about absolute hydrostatic pressure values in the labyrinth. Hydrostatic pressure of the endolymphatic system was recorded in all three semicircular canals. Mean pressure values were 4.06 cmH(2)O ± 0.61 in the posterior, 3.36 cmH(2)O ± 0.94 in the anterior and 3.85 cmH(2)O ± 1.38 in the lateral semicircular canal. Overall hydrostatic pressure in the vestibular organ was 3.76 cmH(2)O ± 0.36. Endolymphatic hydrostatic pressure in all three semicircular canals is the same (p = 0.310). With regard to known endolymphatic pressure values in the cochlea from past studies vestibular pressure values are comparable to cochlear values. Until now it is not known whether the reuniens duct and the Bast's valve which are the narrowest passages in the endolymphatic system are open or closed. Present data show that most likely the endolymphatic system is a functionally open entity.

  2. Experimental research and development of main circulation pump bearings in reactor plants using heavy liquid-metal coolants

    International Nuclear Information System (INIS)

    Zudin, A.; Beznosov, A.; Chernysh, A.; Prikazchikov, G.

    2015-01-01

    At the present time, specialists in Russia are engaged in designing the BREST-OD-300 fast neutron lead-coolant reactor plant. There is currently no experience in designing and operating axial pumps of lead-coolant reactor plants, including one of their major units – bearing unit. Selection and substantiation of operating and structural parameters of plain friction bearings used in main circulation pumps of reactor plants running on heavy liquid-metal coolants are important tasks that are solved at the NNSTU. Development of a feasible procedure for designing bearings and its components operating within the structure of the main circulation pump of a reactor plant running on a heavy liquid-metal coolant as well as guidelines for an optimized structural scheme of such bearings set a goal of performing a range of theoretically-calculated and experimental works. The report contains testing data of a hydrostatic bearing with reciprocal fricative choking tested on the NNSTU FT-4 bench running on a lead coolant within the range of 420-500degC. There have been presented a scheme of a bench for testing a contact friction bearing on a high-temperature coolant and the results of investigation tests of bearings of such type at T = 450 ÷ 500degC. Material of the bearing sleeve is steel 08X18H10T, and a possibility is provided with regard to installation of the bearing sleeves and shaft made of non-metal materials (ceramic materials, silicified graphite, etc.). The presented testing data of plain friction bearings operating in a high-temperature heavy liquid-metal coolant will serve as a ground for making an alternative choice of a plain friction bearing for the main circulation pump of a reactor plant running on a heavy liquid-metal coolant. (author)

  3. Nanoprecipitation in bearing steels

    International Nuclear Information System (INIS)

    Barrow, A.T.W.; Rivera-Diaz-del-Castillo, P.E.J.

    2011-01-01

    θ-phase is the main hardening species in bearing steels and appears in both martensitically and bainitically hardened microstructures. This work presents a survey of the microstrucural features accompanying nanoprecipitation in bearing steels. Nanoprecipitate structures formed in 1C-1.5Cr wt.% with additions of Cr, Mn, Mo, Si and Ni are studied. The work is combined with thermodynamic calculations and neural networks to predict the expected matrix composition, and whether this will transform martensitically or bainitically. Martensite tetragonality, composition and the amount of retained austenite are related to hardness and the type of nanoprecipitate structures in martensitic grades. The θ-phase volume fraction, the duration of the bainite to austenite transformation and the amount of retained austenite are related to hardness and a detailed quantitative description of the precipitate nanostructures. Such description includes compositional studies using energy-dispersive spectroscopy, which shows that nanoprecipitate formation takes place under paraequilibrium. Special attention is devoted to a novel two-step bainite tempering process which shows maximum hardness; we prove that this is the most effective process for incorporating solute into the precipitates, which are finer than those resulting from one-step banitic transformation processes.

  4. Superconducting bearings in flywheels

    Energy Technology Data Exchange (ETDEWEB)

    Coombs, T.A.; Campbell, A.M.; Ganney, I.; Lo, W. [Cambridge Univ. (United Kingdom). Interdisciplinary Research Centre in Superconductivity (IRC); Twardowski, T. [International Energy Systems, Chester High Road, Neston, South Wirral (United Kingdom); Dawson, B. [British Nuclear Fuels, Capenhurst, South Wirral (United Kingdom)

    1998-05-01

    Investigations are being carried out into the use of superconducting magnetic bearings to levitate energy storage flywheels. In a planned program of work, Cambridge University are aiming to produce a practical bearing system for Pirouette(TM). The Pirouette(TM) system is designed to provide 5 kWh of recoverable energy which is currently recoverable at a rate of 5 kW (future revisions will provide up to 50 kW). IES (a British Nuclear Fuels subsidiary) the owners of the Pirouette(TM) machine have supplied Cambridge with a flywheel. This flywheel weighs >40 kg and is being levitated using an Evershed-type arrangement in which the superconductor is being used to stabilize the interaction between two magnets. To date we have demonstrated stable levitation in static and low speed tests in a rig designed for low speeds of rotation in air. A second rig which is currently under construction at BNFL will run in vacuum at speeds of up to 50 (orig.) 5 refs.

  5. Low hydrostatic head electrolyte addition to fuel cell stacks

    International Nuclear Information System (INIS)

    Kothmann, R.E.

    1983-01-01

    A fuel cell and system for supply electrolyte, as well as fuel and an oxidant to a fuel cell stack having at least two fuel cells, each of the cells having a pair of spaced electrodes and a matrix sandwiched therebetween, fuel and oxidant paths associated with a bipolar plate separating each pair of adjacent fuel cells and an electrolyte fill path for adding electrolyte to the cells and wetting said matrices. Electrolyte is flowed through the fuel cell stack in a back and forth fashion in a path in each cell substantially parallel to one face of opposite faces of the bipolar plate exposed to one of the electrodes and the matrices to produce an overall head uniformly between cells due to frictional pressure drop in the path for each cell free of a large hydrostatic head to thereby avoid flooding of the electrodes. The bipolar plate is provided with channels forming paths for the flow of the fuel and oxidant on opposite faces thereof, and the fuel and the oxidant are flowed along a first side of the bipolar plate and a second side of the bipolar plate through channels formed into the opposite faces of the bipolar plate, the fuel flowing through channels formed into one of the opposite faces and the oxidant flowing through channels formed into the other of the opposite faces

  6. High hydrostatic pressure and biology: a brief history.

    Science.gov (United States)

    Demazeau, Gérard; Rivalain, Nolwennig

    2011-03-01

    Pressure as a thermodynamical parameter was successively introduced in physics, hydrometallurgy, geochemistry, and biology. In all cases, the main objective was to recreate a natural phenomenon (gas or liquid compressibility, synthesis or crystal growth of minerals, survival of deep sea microorganisms…). The introduction of high hydrostatic pressure (HHP) in Biology was an important scientific feature over the last hundred years. This paper describes the different steps that have led to the spreading of pressure in biology and the opening of new frontiers either in basic and applied researches due to the specific characteristics of the pressure parameter. Because of the low energy conveyed by this parameter, leading to the preservation of most organoleptic properties of foods, and its ability to inactivate many pathogens, the use of HHP began to spread at the end of the twentieth century into the food industry, in particular for the development of pathogen inactivation processes. Today, even if this field is still the first application domain for HHP, more and more research works have shown that this parameter could be of great interest in health and medicine sciences.

  7. 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.

  8. 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.

  9. MHD Kelvin-Helmholtz instability in non-hydrostatic equilibrium

    International Nuclear Information System (INIS)

    Laghouati, Y; Bouabdallah, A; Zizi, M; Alemany, A

    2007-01-01

    The present work deals with the linear stability of a magnetohydrodynamic shear flow so that a stratified inviscid fluid rotating about a vertical axis when a uniform magnetic field is applied in the direction of the streaming or zonal flow. In geophysical flow, the stability of the flow is determined by taking into account the nonhydrostatic condition depending on Richardson number R i and the deviation δ from hydrostatic equilibrium. According to Stone (Stone P H 1971 J. Fluid. Mech. 45 659), it is shown that such deviation δ decreases the growth rates of three kinds of instability which can appear as geostrophic (G), symmetric (S) and Kelvin-Helmholtz (K-H) instabilities. To be specific, the evolution of the flow is therefore considered in the light of the influence of magnetic field, particularly, on K-H instability. The results of this study are presented by the linear stability of a magnetohydrodynamic, with horizontal free-shear flow of stratified fluid, subject to rotation about the vertical axis and uniform magnetic field in the zonal direction. Results are discussed and compared to previous works as Chandrasekhar (Chandrasekhar S 1961 Hydrodynamic and hydromagnetic stability (Oxford: Clarendon Press) chapter 11 pp 481-513) and Stone

  10. Effect of hydrostatic pressure on gas solubilization in micelles.

    Science.gov (United States)

    Meng, Bin; Ashbaugh, Henry S

    2015-03-24

    Molecular dynamics simulations of anionic sodium decylsulfate and nonionic pentaethylene glycol monodecyl ether micelles in water have been performed to examine the impact of hydrostatic pressure on argon solubilization as a function of pressure. The potential-of-mean force between the micelles and argon demonstrates that nonpolar gases are attracted to the interiors of both micelles. The affinity of argon for micelle interiors, however, decreases with increasing pressure as a result of the comparatively higher molar volume of argon inside assemblies. We evaluate solubility enhancement coefficients, which describe the drop in the solute chemical potential as a function of the micellized surfactant concentration, to quantify the impact of micellization on gas solubilization. While argon is similarly attracted to the hydrophobic cores of both micelles, the gas is more effectively sequestered within nonionic micelles compared with anionic micelles as a result of salting out by charged head groups and accompanying counterions. The solubility enhancement coefficients of both micelles decrease with increasing pressure, reflecting the changing forces observed in the potentials-of-mean force. An analytical liquid drop model is proposed to describe the pressure dependence of argon solubilization within micelles that captures the simulation solubility enhancement coefficients after fitting an effective micelle radius for each surfactant.

  11. Raman study of radiation-damaged zircon under hydrostatic compression

    Science.gov (United States)

    Nasdala, Lutz; Miletich, Ronald; Ruschel, Katja; Váczi, Tamás

    2008-12-01

    Pressure-induced changes of Raman band parameters of four natural, gem-quality zircon samples with different degrees of self-irradiation damage, and synthetic ZrSiO4 without radiation damage, have been studied under hydrostatic compression in a diamond anvil cell up to ~10 GPa. Radiation-damaged zircon shows similar up-shifts of internal SiO4 stretching modes at elevated pressures as non-damaged ZrSiO4. Only minor changes of band-widths were observed in all cases. This makes it possible to estimate the degree of radiation damage from the width of the ν3(SiO4) band of zircon inclusions in situ, almost independent from potential “fossilized pressures” or compressive strain acting on the inclusions. An application is the non-destructive analysis of gemstones such as corundum or spinel: broadened Raman bands are a reliable indicator of self-irradiation damage in zircon inclusions, whose presence allows one to exclude artificial color enhancement by high-temperature treatment of the specimen.

  12. Magnetoresistance in CePtSn under high hydrostatic pressures

    International Nuclear Information System (INIS)

    Misek, M.; Prokleska, J.; Javorsky, P.; Sechovsky, V.

    2009-01-01

    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 c LF of the low field (LF) transition up to ∼1.2 GPa where only one transition is observed at ∼11.5 T. For pressures above 1.2 GPa we observe two transitions again and B c LF decreases with further increasing pressure to reach B c LF ∼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.

  13. Induction of rice mutations by high hydrostatic pressure.

    Science.gov (United States)

    Zhang, Wei; Liu, Xuncheng; Zheng, Feng; Zeng, Songjun; Wu, Kunlin; da Silva, Jaime A Teixeira; Duan, Jun

    2013-09-01

    High hydrostatic pressure (HHP) is an extreme thermo-physical factor that affects the synthesis of DNA, RNA and proteins and induces mutagenesis in microorganisms. Our previous studies showed that exposure to 25-100 MPa HHP for 12 h retarded the germination and affected the viability of rice (Oryza sativa L.) seeds, increased the tolerance of rice plants to cold stress and altered gene expression patterns in germinating rice seeds. However, the mutagenic effect of HHP on rice remains unknown. In this study, exposure to 25, 50, 75 or 100 MPa for 12 h HHP could efficiently induce variation in rice plants. Furthermore, presoaking time and HHP strength during HHP treatment affected the efficiency of mutation. In addition, the Comet assay revealed that exposure to 25-100 MPa HHP for 12 h induced DNA strand breakage in germinating seeds and may have been the source of mutations. Our results suggest that HHP is a promising physical mutagen in rice breeding. Copyright © 2013 Elsevier Masson SAS. All rights reserved.

  14. Exocytosis from chromaffin cells: hydrostatic pressure slows vesicle fusion

    Science.gov (United States)

    Stühmer, Walter

    2015-01-01

    Pressure affects reaction kinetics because chemical transitions involve changes in volume, and therefore pressure is a standard thermodynamic parameter to measure these volume changes. Many organisms live in environments at external pressures other than one atmosphere (0.1 MPa). Marine animals have adapted to live at depths of over 7000 m (at pressures over 70 MPa), and microorganisms living in trenches at over 110 MPa have been retrieved. Here, kinetic changes in secretion from chromaffin cells, measured as capacitance changes using the patch-clamp technique at pressures of up to 20 MPa are presented. It is known that these high pressures drastically slow down physiological functions. High hydrostatic pressure also affects the kinetics of ion channel gating and the amount of current carried by them, and it drastically slows down synaptic transmission. The results presented here indicate a similar change in volume (activation volume) of 390 ± 57 Å3 for large dense-core vesicles undergoing fusion in chromaffin cells and for degranulation of mast cells. It is significantly larger than activation volumes of voltage-gated ion channels in chromaffin cells. This information will be useful in finding possible protein conformational changes during the reactions involved in vesicle fusion and in testing possible molecular dynamic models of secretory processes. PMID:26009771

  15. Hydrostatic pressure effects on the dielectric response of potassium cyanide

    International Nuclear Information System (INIS)

    Ortiz Lopez, J.

    1992-01-01

    The complex dielectric constant of crystalline KCN was measured under hydrostatic pressures up to 6.1 kbar in the temperature and frequency ranges of 50-300 K and 10-10 5 Hz, respectively. It is found that the pressure derivative of the real part of the dielectric constant at all measured temperatures is negative. From these results we obtain estimates for the pressure and volume derivatives of polarizabilities. The anomaly in the real part of the dielectric constant at the elastic order-disorder transition shifts to higher temperatures with increasing pressure at a rate of 2.05 K/kbar. By carefully avoiding thermal cycling through this transition we find no evidence of the monoclinic phase reported to exist in the P-T phase diagram of KCN at relatively low pressures. Dielectric loss measurements show thermally-activated CN - reorientation rates in the elastically ordered phase with pressure-independent reorientational barriers and decreasing attempt frequencies for increasing pressures. Additional pressure effects on dielectric loss allow to obtain the pressure derivative of the antiferroelectric transition temperature as 1.97 K/kbar. (Author)

  16. Computational design of rolling bearings

    CERN Document Server

    Nguyen-Schäfer, Hung

    2016-01-01

    This book comprehensively presents the computational design of rolling bearings dealing with many interdisciplinary difficult working fields. They encompass elastohydrodynamics (EHD), Hertzian contact theory, oil-film thickness in elastohydrodynamic lubrication (EHL), bearing dynamics, tribology of surface textures, fatigue failure mechanisms, fatigue lifetimes of rolling bearings and lubricating greases, Weibull distribution, rotor balancing, and airborne noises (NVH) in the rolling bearings. Furthermore, the readers are provided with hands-on essential formulas based on the up-to-date DIN ISO norms and helpful examples for computational design of rolling bearings. The topics are intended for undergraduate and graduate students in mechanical and material engineering, research scientists, and practicing engineers who want to understand the interactions between these working fields and to know how to design the rolling bearings for automotive industry and many other industries.

  17. New understanding of the effect of hydrostatic pressure on the corrosion of Ni–Cr–Mo–V high strength steel

    International Nuclear Information System (INIS)

    Yang, Yange; Zhang, Tao; Shao, Yawei; Meng, Guozhe; Wang, Fuhui

    2013-01-01

    Highlights: •Stress distributions of pits under different hydrostatic pressures are simulated. •Corrosion model of Ni–Cr–Mo–V steel under hydrostatic pressure is established. •A novel understanding of the effect of hydrostatic pressure is proposed. -- Abstract: Corrosion of Ni–Cr–Mo–V high strength steel at different hydrostatic pressures is investigated by scanning electron microscopy (SEM) and finite element analysis (FEA). The results indicate that corrosion pits of Ni–Cr–Mo–V high strength steel originate from inclusions in the steel and high hydrostatic pressures accelerate pit growth rate parallel to steel and the coalescence rate of neighbouring pits, which lead to the fast formation of uniform corrosion. Corrosion of Ni–Cr–Mo–V high strength steel under high hydrostatic pressure is the interaction result between electrochemical corrosion and elastic stress

  18. Controlled hydrostatic pressure stress downregulates the expression of ribosomal genes in preimplantation embryos: a possible protection mechanism?

    Science.gov (United States)

    Bock, I; Raveh-Amit, H; Losonczi, E; Carstea, A C; Feher, A; Mashayekhi, K; Matyas, S; Dinnyes, A; Pribenszky, C

    2016-04-01

    The efficiency of various assisted reproductive techniques can be improved by preconditioning the gametes and embryos with sublethal hydrostatic pressure treatment. However, the underlying molecular mechanism responsible for this protective effect remains unknown and requires further investigation. Here, we studied the effect of optimised hydrostatic pressure treatment on the global gene expression of mouse oocytes after embryonic genome activation. Based on a gene expression microarray analysis, a significant effect of treatment was observed in 4-cell embryos derived from treated oocytes, revealing a transcriptional footprint of hydrostatic pressure-affected genes. Functional analysis identified numerous genes involved in protein synthesis that were downregulated in 4-cell embryos in response to hydrostatic pressure treatment, suggesting that regulation of translation has a major role in optimised hydrostatic pressure-induced stress tolerance. We present a comprehensive microarray analysis and further delineate a potential mechanism responsible for the protective effect of hydrostatic pressure treatment.

  19. Grease lubrication in rolling bearings

    CERN Document Server

    Lugt, Piet M

    2012-01-01

    The definitive book on the science of grease lubrication for roller and needle bearings in industrial and vehicle engineering. Grease Lubrication in Rolling Bearings provides an overview of the existing knowledge on the various aspects of grease lubrication (including lubrication systems) and the state of the art models that exist today. The book reviews the physical and chemical aspects of grease lubrication, primarily directed towards lubrication of rolling bearings. The first part of the book covers grease composition, properties and rheology, including thermal

  20. Non-hydrostatic semi-elastic hybrid-coordinate SISL extension of HIRLAM. Part II: numerical testing

    OpenAIRE

    Rõõm, Rein; Männik, Aarne; Luhamaa, Andres; Zirk, Marko

    2007-01-01

    The semi-implicit semi-Lagrangian (SISL), two-time-level, non-hydrostatic numerical scheme, based on the non-hydrostatic, semi-elastic pressure-coordinate equations, is tested in model experiments with flow over given orography (elliptical hill, mountain ridge, system of successive ridges) in a rectangular domain with emphasis on the numerical accuracy and non-hydrostatic effect presentation capability. Comparison demonstrates good (in strong primary wave generation) to satisfactory (in weak ...

  1. Use of an Ethanol-Driven Pressure Cell to Measure Hydrostatic Pressure Response of Protein-Stabilized Gold Nanoclusters

    Science.gov (United States)

    2016-01-01

    ARL-TR-7577 ● JAN 2016 US Army Research Laboratory Use of an Ethanol-Driven Pressure Cell to Measure Hydrostatic Pressure ...ARL-TR-7577 ● JAN 2016 US Army Research Laboratory Use of an Ethanol-Driven Pressure Cell to Measure Hydrostatic Pressure Response of...DATES COVERED (From - To) May 2014–September 2014 4. TITLE AND SUBTITLE Use of an Ethanol-Driven Pressure Cell to Measure Hydrostatic Pressure

  2. 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.

  3. Cyclic hydrostatic pressure stimulates enhanced bone development in the foetal chick femur in vitro.

    Science.gov (United States)

    Henstock, J R; Rotherham, M; Rose, J B; El Haj, A J

    2013-04-01

    Mechanical loading of bone and cartilage in vivo results in the generation of cyclic hydrostatic forces as bone compression is transduced to fluid pressure in the canalicular network and the joint synovium. It has therefore been suggested that hydrostatic pressure is an important stimulus by which osteochondral cells and their progenitors sense and respond to mechanical loading in vivo. In this study, hydrostatic pressure regimes of 0-279kPa at 0.005-2Hz were applied to organotypically cultured ex vivo chick foetal femurs (e11) for 1hour per day in a custom designed bioreactor for 14days and bone formation assessed by X-ray microtomography and qualified by histology. We found that the mineralised portion of the developing femur cultured under any cyclic hydrostatic pressure regime was significantly larger and/or denser than unstimulated controls but that constant (non-cycling) hydrostatic pressure had no effect on bone growth. Further experiments showed that the increase in bone formation was directly proportional to stimulation frequency (R(2)=0.917), but independent of the magnitude of the pressure applied, whilst even very low frequencies of stimulation (0.005Hz) had significant effects on bone growth. Expression of Type-II collagen in both epiphyses and diaphysis was significantly upregulated (1.48-fold and 1.95-fold respectively), together with osteogenic genes (osteonectin and osteopontin) and the osteocyte maturation marker CD44. This work demonstrates that cyclic hydrostatic pressure promotes bone growth and mineralisation in a developmental model and supports the hypothesis that hydrostatic forces play an important role in regulating bone growth and remodelling in vivo. Copyright © 2013 Elsevier Inc. All rights reserved.

  4. 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.)

  5. Superconducting bearings for flywheel applications

    Energy Technology Data Exchange (ETDEWEB)

    Abrahamsen, Asger Bech

    2001-05-01

    A literature study on the application of superconducting bearings in energy storage flywheel systems. The physics of magnetic levitation and superconductors are presented in the first part of the report, followed by a discussion of the literature found on the applications of superconducting bearings in flywheels. (au)

  6. Superconducting bearings for flywheel applications

    DEFF Research Database (Denmark)

    Abrahamsen, A.B.

    2001-01-01

    A literature study on the application of superconducting bearings in energy storage flywheel systems. The physics of magnetic levitation and superconductors are presented in the first part of the report, followed by a discussion of the literature found onthe applications of superconducting bearings...

  7. Space Station alpha joint bearing

    Science.gov (United States)

    Everman, Michael R.; Jones, P. Alan; Spencer, Porter A.

    1987-01-01

    Perhaps the most critical structural system aboard the Space Station is the Solar Alpha Rotary Joint which helps align the power generation system with the sun. The joint must provide structural support and controlled rotation to the outboard transverse booms as well as power and data transfer across the joint. The Solar Alpha Rotary Joint is composed of two transition sections and an integral, large diameter bearing. Alpha joint bearing design presents a particularly interesting problem because of its large size and need for high reliability, stiffness, and on orbit maintability. The discrete roller bearing developed is a novel refinement to cam follower technology. It offers thermal compensation and ease of on-orbit maintenance that are not found in conventional rolling element bearings. How the bearing design evolved is summarized. Driving requirements are reviewed, alternative concepts assessed, and the selected design is described.

  8. Flywheel Challenge: HTS Magnetic Bearing

    International Nuclear Information System (INIS)

    Werfel, F N; Floegel-Delor, U; Riedel, T; Rothfeld, R; Wippich, D; Goebel, B

    2006-01-01

    A 200 mm cylindrical engineering prototype high temperature superconducting (HTS) was designed and fabricated. Measurements show that the 17 kg PM rotor can suspend safely 1000 kg in axial direction and 470 kg radially. The rationale for the bearing performance is to stabilize a 400 kg rotor of a new compact 5 kWh/280 kW flywheel energy storage system (COM - FESS). Measurements of the magnetic bearing force, stiffness and drag-torque are presented indicated the successful targeting a milestone in the HTS bearing technology. The influence of the PM configuration and the YBCO temperature on the bearing performance was experimentally studied, providing high-force or high-stiffness behaviour. The axial stiffness 5 kN/mm at 0.5 mm displacement is the highest value of a HTS bearing we know

  9. Simulation of non-hydrostatic gravity wave propagation in the upper atmosphere

    Directory of Open Access Journals (Sweden)

    Y. Deng

    2014-04-01

    Full Text Available The high-frequency and small horizontal scale gravity waves may be reflected and ducted in non-hydrostatic simulations, but usually propagate vertically in hydrostatic models. To examine gravity wave propagation, a preliminary study has been conducted with a global ionosphere–thermosphere model (GITM, which is a non-hydrostatic general circulation model for the upper atmosphere. GITM has been run regionally with a horizontal resolution of 0.2° long × 0.2° lat to resolve the gravity wave with wavelength of 250 km. A cosine wave oscillation with amplitude of 30 m s−1 has been applied to the zonal wind at the low boundary, and both high-frequency and low-frequency waves have been tested. In the high-frequency case, the gravity wave stays below 200 km, which indicates that the wave is reflected or ducted in propagation. The results are consistent with the theoretical analysis from the dispersion relationship when the wavelength is larger than the cutoff wavelength for the non-hydrostatic situation. However, the low-frequency wave propagates to the high altitudes during the whole simulation period, and the amplitude increases with height. This study shows that the non-hydrostatic model successfully reproduces the high-frequency gravity wave dissipation.

  10. 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.

  11. Fluoroscopy-guided hydrostatic reduction of intussusception in infancy: role of pharmacological premedication.

    Science.gov (United States)

    Esposito, Francesco; Ambrosio, Concetta; De Fronzo, Simona; Panico, Maria Rita; D'Aprano, Marilena; Giugliano, Anna Marcella; Noviello, Domenico; Oresta, Patrizia

    2015-06-01

    Intussusception is one of the most common causes of paediatric emergency. Fluoroscopy-guided hydrostatic reduction is a common nonoperative management strategy for the treatment of intussusception. The role of pharmacological premedication in increasing the success rate of hydrostatic reduction is still controversial. The purpose of this study was to verify the presence of a possible correlation between pharmacological premedication and the percentage of hydrostatic reduction of intussusception in paediatric patients. This study considered children with a diagnosis of idiopathic intussusception treated at our hospital between January 2007 and June 2013. One group of patients underwent hydrostatic reduction by barium enema without any preliminary therapy. A second group of patients received pharmacological premedication with both a sedative and an anti-oedematous agent before the procedure. A total of 398 patients were treated with barium enema for therapeutic purposes. In the group of patients who received no premedication (n = 254), 165 (65 %) children achieved hydrostatic reduction of the intussusception. Among the patients who received pharmacological premedication prior to barium enema (n = 144), 122 (85 %) children achieved resolution of the intussusception. Our study shows that the use of pharmacological premedication is effective for the reduction of the intussusception, as its limit patient stress, fluoroscopic time and radiation dose.

  12. [An easy, safe and affective method for the treatment of intussusception: ultrasound-guided hydrostatic reduction].

    Science.gov (United States)

    Ülger, Fatma Esra Bahadır; Ülger, Aykut; Karakaya, Ali Erdal; Tüten, Fatih; Katı, Ömer; Çolak, Mustafa

    2014-03-01

    Intussusception is one of the important causes of intestinal obstruction in children. Hydrostatic reduction under ultrasound guidance is a popular treatment method for intussusception. In the present study, we aimed to explain the demographic characteristics of and treatment approaches in patients diagnosed with intussusception by ultrasound. Forty-one patients diagnosed with intussusception by ultrasound between August 2011 and May 2013 were retrospectively analyzed. Twenty-four of these patients who had no contraindications had been treated with ultrasound-guided hydrostatic reduction. Twenty-four of the patients were male and 17 were female, a 1.4/1 male-to-female ratio. The majority of the patients were between the ages of 6-24 months and 2-5 years. The mean age was 31.12±26.32 months (range 3-125). Patients were more frequently diagnosed in April and May. Seventeen patients who had clinical contraindications enrolled directly for surgery. In 20 of the 24 patients who underwent ultrasound-guided hydrostatic reduction, reduction was achieved. Three experienced recurrence. In two of these patients, successful reduction was achieved with the second attempt. The remaining patient was enrolled for surgery. Hydrostatic reduction was performed 26 times on these 24 patients, and in 22, success was achieved (84.6%). No procedure-related complications occurred in the patients. Ultrasound-guided hydrostatic reduction, with its high success rates and lack of radiation risk, should be the first choice therapeutic approach for children diagnosed with intussusception.

  13. Performance of an Electro-Hydrostatic Actuator on the F-18 Systems Research Aircraft

    Science.gov (United States)

    Navarro, Robert

    1997-01-01

    An electro-hydrostatic actuator was evaluated at NASA Dryden Flight Research Center, Edwards, California. The primary goal of testing this actuator system was the flight demonstration of power-by-wire technology on a primary flight control surface. The electro-hydrostatic actuator uses an electric motor to drive a hydraulic pump and relies on local hydraulics for force transmission. This actuator replaced the F-18 standard left aileron actuator on the F-18 Systems Research Aircraft and was evaluated throughout the Systems Research Aircraft flight envelope. As of July 24, 1997 the electro-hydrostatic actuator had accumulated 23.5 hours of flight time. This paper presents the electro-hydrostatic actuator system configuration and component description, ground and flight test plans, ground and flight test results, and lessons learned. This actuator performs as well as the standard actuator and has more load capability than required by aileron actuator specifications of McDonnell- Douglas Aircraft, St. Louis, Missouri. The electro-hydrostatic actuator system passed all of its ground tests with the exception of one power-off test during unloaded dynamic cycling.

  14. 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.

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

    Science.gov (United States)

    Rao, Fang; Yang, Ren-Qiang; Chen, Xiao-Shu; Xu, Jin-Song; Fu, Hui-Min; Su, Hai; Wang, Ling

    2014-01-01

    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.

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

    International Nuclear Information System (INIS)

    Galindez-Ramirez, G; Perez-Merchancano, S T; Paredes Gutierrez, H; Gonzalez, J D

    2010-01-01

    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. The effect of the rate of hydrostatic pressure depressurization on cells in culture.

    Science.gov (United States)

    Tworkoski, Ellen; Glucksberg, Matthew R; Johnson, Mark

    2018-01-01

    Changes in hydrostatic pressure, at levels as low as 10 mm Hg, have been reported in some studies to alter cell function in vitro; however, other studies have found no detectable changes using similar methodologies. We here investigate the hypothesis that the rate of depressurization, rather than elevated hydrostatic pressure itself, may be responsible for these reported changes. Hydrostatic pressure (100 mm Hg above atmospheric pressure) was applied to bovine aortic endothelial cells (BAECs) and PC12 neuronal cells using pressurized gas for periods ranging from 3 hours to 9 days, and then the system was either slowly (~30 minutes) or rapidly (~5 seconds) depressurized. Cell viability, apoptosis, proliferation, and F-actin distribution were then assayed. Our results did not show significant differences between rapidly and slowly depressurized cells that would explain differences previously reported in the literature. Moreover, we found no detectable effect of elevated hydrostatic pressure (with slow depressurization) on any measured variables. Our results do not confirm the findings of other groups that modest increases in hydrostatic pressure affect cell function, but we are not able to explain their findings.

  18. Use of pressurized eccentric tubes to study the effect of hydrostatic stress on swelling

    International Nuclear Information System (INIS)

    Wolfer, W.G.; Reiley, T.C.

    1977-05-01

    A technique for measuring the effect of hydrostatic stress on radiation-induced swelling is presented. This technique is based on the nonuniform hydrostatic stress that arises when an eccentric tube (a tube with inner and outer surfaces having dissimilar centers of revolution) is internally pressurized. The elastic analyses of the thin- and thick-walled eccentric tube are given. The elastic stress state is allowed to relax plastically, based on a constitutive law for deformation during neutron irradiation. In this case, the constitutive law contains a linearly stress-dependent deviatoric strain rate and a dilatation rate that is linearly dependent on hydrostatic stress. Emphasis is placed on the specimen design and experimental procedure for in-reactor experiments in which the coefficient relating hydrostatic stress and swelling is sought. It is shown that, for the 316L stainless steel specimens placed in EBR-II, we may expect that any appreciable effect of hydrostatic stress on swelling will be observable through changes in specimen curvature

  19. Journal bearing impedance descriptions for rotordynamic applications

    NARCIS (Netherlands)

    Childs, D.W.; Moes, H.; Leeuwen, van H.J.

    1977-01-01

    Bearing impedance vectors are introduced for plain journal bearings which define the bearing reaction force components as a function of the bearing motion. Impedance descriptions are developed directly for the approximate Ocvirk (short) and Sommerfeld (long) bearing solutions. The impedance vector

  20. A free-surface hydrodynamic model for density-stratified flow in the weakly to strongly non-hydrostatic regime

    International Nuclear Information System (INIS)

    Shen, Colin Y.; Evans, Thomas E.

    2004-01-01

    A non-hydrostatic density-stratified hydrodynamic model with a free surface has been developed from the vorticity equations rather than the usual momentum equations. This approach has enabled the model to be obtained in two different forms, weakly non-hydrostatic and fully non-hydrostatic, with the computationally efficient weakly non-hydrostatic form applicable to motions having horizontal scales greater than the local water depth. The hydrodynamic model in both its weakly and fully non-hydrostatic forms is validated numerically using exact nonlinear non-hydrostatic solutions given by the Dubriel-Jacotin-Long equation for periodic internal gravity waves, internal solitary waves, and flow over a ridge. The numerical code is developed based on a semi-Lagrangian scheme and higher order finite-difference spatial differentiation and interpolation. To demonstrate the applicability of the model to coastal ocean situations, the problem of tidal generation of internal solitary waves at a shelf-break is considered. Simulations carried out with the model obtain the evolution of solitary wave generation and propagation consistent with past results. Moreover, the weakly non-hydrostatic simulation is shown to compare favorably with the fully non-hydrostatic simulation. The capability of the present model to simulate efficiently relatively large scale non-hydrostatic motions suggests that the weakly non-hydrostatic form of the model may be suitable for application in a large-area domain while the computationally intensive fully non-hydrostatic form of the model may be used in an embedded sub-domain where higher resolution is needed

  1. Primary cilia modulate Ihh signal transduction in response to hydrostatic loading of growth plate chondrocytes.

    Science.gov (United States)

    Shao, Yvonne Y; Wang, Lai; Welter, Jean F; Ballock, R Tracy

    2012-01-01

    Indian hedgehog (Ihh) is a key component of the regulatory apparatus governing chondrocyte proliferation and differentiation in the growth plate. Recent studies have demonstrated that the primary cilium is the site of Ihh signaling within the cell, and that primary cilia are essential for bone and cartilage formation. Primary cilia are also postulated to act as mechanosensory organelles that transduce mechanical forces acting on the cell into biological signals. In this study, we used a hydrostatic compression system to examine Ihh signal transduction under the influence of mechanical load. Our results demonstrate that hydrostatic compression increased both Ihh gene expression and Ihh-responsive Gli-luciferase activity. These increases were aborted by disrupting the primary cilia structure with chloral hydrate. These results suggest that growth plate chondrocytes respond to hydrostatic loading by increasing Ihh signaling, and that the primary cilium is required for this mechano-biological signal transduction to occur. Copyright © 2011 Elsevier Inc. All rights reserved.

  2. Diagnosis of hydrostatic versus increased permeability pulmonary edema with chest radiographic criteria in critically ILL patients

    International Nuclear Information System (INIS)

    Aberle, D.R.; Wiener-Kronish, J.P.; Webb, W.R.; Matthay, M.A.

    1987-01-01

    To evaluate chest radiographic criteria in distinguishing mechanisms of pulmonary edema, the authors studied 45 intubated patients with extensive edema. Edema type was clinically classified by the ratio of alveolar edema-to-plasma protein concentration in association with compatible clinical/hemodynamic parameters. Chest films were scored as hydrostatic, permeability, or mixed by three readers in blinded fashion based on cardiac size, vascular pedicle width, distribution of edema, effusions, peribronchial cuffs, septal lines, or air bronchograms. Overall radiographic score accurately identified 87% of patients with hydrostatic edema but only 60% of those with permeability edema. Edema distribution was most discriminating, with a patchy peripheral pattern relatively specific for clinical permeability edema. Hydrostatic features on chest radiograph were common with permeability edema, including effusions (36%), widened pedicle (56%), cuffs (72%), or septa (40%). The authors conclude that the chest radiograph is limited in distinguishing edema mechanism in the face of extensive pulmonary edema

  3. Use of hydrostatic pressure for modulation of protein chemical modification and enzymatic selectivity.

    Science.gov (United States)

    Makarov, Alexey A; Helmy, Roy; Joyce, Leo; Reibarkh, Mikhail; Maust, Mathew; Ren, Sumei; Mergelsberg, Ingrid; Welch, Christopher J

    2016-05-11

    Using hydrostatic pressure to induce protein conformational changes can be a powerful tool for altering the availability of protein reactive sites and for changing the selectivity of enzymatic reactions. Using a pressure apparatus, it has been demonstrated that hydrostatic pressure can be used to modulate the reactivity of lysine residues of the protein ubiquitin with a water-soluble amine-specific homobifunctional coupling agent. Fewer reactive lysine residues were observed when the reaction was carried out under elevated pressure of 3 kbar, consistent with a pressure-induced conformational change of ubiquitin that results in fewer exposed lysine residues. Additionally, modulation of the stereoselectivity of an enzymatic transamination reaction was observed at elevated hydrostatic pressure. In one case, the minor diasteromeric product formed at atmospheric pressure became the major product at elevated pressure. Such pressure-induced alterations of protein reactivity may provide an important new tool for enzymatic reactions and the chemical modification of proteins.

  4. Microstructure and properties of ultrafine grain nickel 200 after hydrostatic extrusion processes

    Science.gov (United States)

    Sitek, R.; Krajewski, C.; Kamiński, J.; Spychalski, M.; Garbacz, H.; Pachla, W.; Kurzydłowski, K. J.

    2012-09-01

    This paper presents the results of the studies of the structure and properties of ultrafine grained nickel 200 obtained by hydrostatic extrusion processes. Microstructure was characterized by means of optical microscopy and electron transmission microscopy. Corrosion resistance was studied by impedance and potentiodynamic methods using an AutoLab PGSTAT 100 potentiostat in 0.1 M Na2SO4 solution and in acidified (by addition of H2SO4) 0.1 M NaCl solution at pH = 4.2 at room temperature. Microhardness tests were also performed. The results showed that hydrostatic extrusion produces a heterogeneous, ultrafine-grained microstructure in nickel 200. The corrosive resistance tests showed that the grain refinement by hydrostatic extrusion is accompanied by a decreased corrosive resistance of nickel 200.

  5. The electrical signature of rock samples exposed to hydrostatic and triaxial pressures

    Energy Technology Data Exchange (ETDEWEB)

    Heikamp, S.; Nover, G. [Bonn Univ., Bonn (Germany). Mineralogical Institute

    2001-04-01

    The electrical signature of sedimentary (carbonate) and crystalline rock samples was studied in hydrostatic and triaxial pressure experiments up to 300 MPa. The aim was to establish a relation between an electrical signal stimulated by an external pressure acting on the sample and the mechanical stability of the rock. Natural open fractures tend to be closed under hydrostatic pressure conditions, whereas in triaxial pressure experiments new fractures are generated. These contrary processes of either decrease or increase in crack density and geometry, cause a decrease or increase in the inner surface of the sample. Such pressure induced variations in pore geometry were investigated by an interpretation and modelling of the frequency dependence of the complex electrical conductivity. In a series of hydrostatic pressure experiments crack-closure was found in the electrical signature by decrease of the model capacitor C being related to crack geometry. This capacitor increases in the triaxial experiments where new fractures were formed.

  6. Primary Cilia Modulate IHH Signal Transduction in Response to Hydrostatic Loading of Growth Plate Chondrocytes

    Science.gov (United States)

    Shao, Y, Yvonne Y.; Wang, Lai; Welter, J, Jean F.; Ballock, R. Tracy

    2011-01-01

    Indian Hedgehog (Ihh) is a key component of the regulatory apparatus governing chondrocyte proliferation and differentiation in the growth plate. Recent studies have demonstrated that the primary cilium is the site of Ihh signaling within the cell, and that primary cilia are essential for bone and cartilage formation. Primary cilia are also postulated to act as mechanosensory organelles that transduce mechanical forces acting on the cell into biological signals. In this study, we used a hydrostatic compression system to examine Ihh signal transduction under the influence of mechanical load. Our results demonstrate that hydrostatic compression increased both Ihh gene expression and Ihh-responsive Gli-luciferase activity. These increases were aborted by disrupting the primary cilia structure with chloral hydrate. These results suggest that growth plate chondrocytes respond to hydrostatic loading by increasing Ihh signaling, and that the primary cilium is required for this mechano-biological signal transduction to occur. PMID:21930256

  7. Hydrogenic donor impurity in parallel-triangular quantum wires: Hydrostatic pressure and applied electric field effects

    International Nuclear Information System (INIS)

    Restrepo, R.L.; Giraldo, E.; Miranda, G.L.; Ospina, W.; Duque, C.A.

    2009-01-01

    The combined effects of the hydrostatic pressure and in-growth direction applied electric field on the binding energy of hydrogenic shallow-donor impurity states in parallel-coupled-GaAs-Ga 1-x Al x As-quantum-well wires are calculated using a variational procedure within the effective-mass and parabolic-band approximations. Results are obtained for several dimensions of the structure, shallow-donor impurity positions, hydrostatic pressure, and applied electric field. Our results suggest that external inputs such us hydrostatic pressure and in-growth direction electric field are two useful tools in order to modify the binding energy of a donor impurity in parallel-coupled-quantum-well wires.

  8. Efficacy of US-guided Hydrostatic Reduction in Children with Intussusception

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Young Min; Chung, Tae Woong; Yoon, Woong; Chang, Nam Kyu; Heo, Suk Hee; Shin, Sang Soo; Lim, Hyo Sun; Jeong, Yong Yeon; Kang, Heoung Keun [Chonnam National University Hospital, Gwangju (Korea, Republic of)

    2007-09-15

    To assess the success rate and efficacy of US-guided hydrostatic reduction in children with intussusception. We retrospectively evaluated the ultrasonographic findings and clinical features of 121 children (M:F=80:41, mean age= 18 months) who underwent US-guided hydrostatic reduction between November, 2002 and February, 2007 for the diagnosis and treatment of intussusception. The 121 patients underwent 147 procedures, including recurred cases. Successful reduction was achieved in 132 cases (89.8% success rate), as confirmed by post-procedure ultrasonography and clinical findings. Emergency operations were performed in the 10 (6.8%) cases of irreducible intussusceptions, 8 of ileocolic type and 2 of ileoileal type. Perforation occurred in 4 cases (2.7%), and seizure in 1 case during the procedure (0.7%). US-guided hydrostatic reduction is a safe and effective tool for the diagnosis and treatment of pediatric intussusception

  9. 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. © 2013 Elsevier Ltd. All rights reserved.

  10. Reactor coolant system hydrostatic test and risk analysis for the first AP1000 unit

    International Nuclear Information System (INIS)

    Cao Hongjun; Yan Xiuping

    2013-01-01

    The cold hydrostatic test scheme of the primary coolant circuit, of the first AP1000 unit was described. Based on the up-stream design documents, standard specifications and design technical requirements, the select principle of test boundary was identified. The design requirements for water quality, pressure, temperature and temporary hydro-test pump were proposed. A reasonable argument for heating and pressurization rate, and cooling and depressurization rate was proposed. The possible problems and risks during the hydrostatic test were analyzed. This test scheme can provide guidance for the revisions and implementations of the follow-up test procedures. It is a good reference for hydrostatic tests of AP1000 units in the future in China. (authors)

  11. On the effect of hydrostatic pressure on the conformational stability of globular proteins.

    Science.gov (United States)

    Graziano, Giuseppe

    2015-12-01

    The model developed for cold denaturation (Graziano, PCCP 2010, 12, 14245-14252) is extended to rationalize the dependence of protein conformational stability upon hydrostatic pressure, at room temperature. A pressure- volume work is associated with the process of cavity creation for the need to enlarge the liquid volume against hydrostatic pressure. This contribution destabilizes the native state that has a molecular volume slightly larger than the denatured state due to voids existing in the protein core. Therefore, there is a hydrostatic pressure value at which the pressure-volume contribution plus the conformational entropy loss of the polypeptide chain are able to overwhelm the stabilizing gain in translational entropy of water molecules, due to the decrease in water accessible surface area upon folding, causing denaturation. © 2015 Wiley Periodicals, Inc.

  12. Hydrostatic pressure and temperature effects of an exciton-donor complex in quantum dots

    International Nuclear Information System (INIS)

    Xie Wenfang

    2012-01-01

    Using the matrix diagonalization method and the compact density-matrix approach, we studied the combined effects of hydrostatic pressure and temperature on the electronic and optical properties of an exciton-donor complex in a disc-shaped quantum dot. We have calculated the binding energy and the oscillator strength of the intersubband transition from the ground state into the first excited state as a function of the dot radius. Based on the computed energies and wave functions, the linear, third-order nonlinear and total optical absorption coefficients as well as the refractive index have been examined. We find that the ground state binding energy and the oscillator strength are strongly affected by the quantum dot radius, hydrostatic pressure and temperature. The results also show that the linear, third-order nonlinear and total absorption coefficients and refractive index changes strongly depend on temperature and hydrostatic pressure.

  13. Eastern slopes grizzly bear project

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2001-01-01

    The cumulative effects of human activities on the grizzly bears in the central Canadian Rockies are not well known. As a result, a project was initiated in 1994 to address the urgent requirement for accurate scientific information on the habitat and populations of grizzly bears in the area of the Banff National Park and Kananaskis Country. This area is probably the most heavily used and developed area where the grizzly still survives. The information gathered throughout the course of this study will be used to better protect and manage the bears and other sensitive carnivores in the region. Using telemetry, researchers are monitoring 25 grizzly bears which were radio-collared in a 22,000 square-kilometer area in the upper Bow Valley drainage of the eastern Alberta slopes. The researchers involved in the project are working with representatives from Husky Oil and Talisman Energy on the sound development of the Moose Mountain oil and gas field without adversely affecting the grizzly bear population. Information collected over seven years indicated that the grizzly bears have few and infrequent offspring. Using the information gathered so far, the location of the Moose Mountain to Jumping Pound pipeline was carefully selected, since the bears recover very slowly from high mortality, and also considering that the food and cover had already been compromised by the high number of roads, trails and other human activities in the area. The status of the population and habitat of the grizzly bear will be assessed upon the conclusion of the field research phase in 2001. Models will be updated using the data obtained during eight years and will assist in the understanding of complex variables that affect grizzly bears.

  14. EFFECT OF BEARING MACROGEOMETRY ON BEARING PERFORMANCE IN ELASTOHYDRODYNAMIC LUBRICATION

    Directory of Open Access Journals (Sweden)

    Emin GÜLLÜ

    2000-01-01

    Full Text Available During manufacturing, ideal dimension and mutual positioning of machine elements proposed in project desing can be achieved only within certain range of tolerances. These tolerances, being classified in two groups, related to micro and macro geometry of machine elements, don't have to effect the functioning of these elements. So, as for all machine elements, investigation of the effects of macro and micro tolerances for journal bearings is important. In this study, we have investigated the effect of macro geometric irregularities of journal bearings on performance characteristics. In this regard, we have studied the change of bearing performance in respect to deviation from ideal circle for an elliptic shaft with small ovality rolling in circular journal bearing.

  15. 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.

  16. Effect of hydrostatic pressure on regional bond strengths of compomers to dentine.

    Science.gov (United States)

    Zheng, L; Pereira, P N; Somphone, P; Nikaido, T; Tagami, J

    2000-09-01

    The aim of this study was to evaluate the effect of hydrostatic pressure on the regional bond strengths of compomers to dentine. Thirty freshly extracted molars were ground flat to expose the dentine and randomly divided into two groups for bonding: no hydrostatic pressure and hydrostatic pressure of 15cm H(2)O. Xeno CF, Dyract AP and F 2000 were applied to dentine surfaces pretreated by the respective bonding systems following the manufactures' instructions, and then restored with Clearfil AP-X. After 24h storage in water, the teeth were sectioned into 0.7-mm thick slabs and visually divided into three regional subgroups: the region communicating with the pulp through dentinal tubules (pulp horn); the region between the pulp horns (center); and the region between the pulp horn and DEJ (periphery). The specimens were trimmed to a cross-sectional area of 1mm(2) and subjected to the micro-tensile bond test. The data were analyzed by one- and three-way ANOVA, and Fisher's PLSD (p0.05). However, hydrostatic pressure significantly decreased the bond strength of F 2000 to all regions (phydrostatic pressure (p>0.05). For Dyract AP and F 2000, the fracture modes were affected by hydrostatic pressure, while, for Xeno CF, there were no significant differences between the fracture modes with non- or positive hydrostatic pressure. Simulated pulpal pressure of 15cm H(2)O had a greater influence on the bond strengths of compomers to dentine than did dentine regions. Therefore, when measuring the bond strengths of compomers to dentine under the simulated in vivo conditions, the wetness of the dentine surface, as well as the intrinsic properties of each material should be seriously considered.

  17. Numerical Simulation of Damage during Forging with Superimposed Hydrostatic Pressure by Active Media

    International Nuclear Information System (INIS)

    Behrens, B.-A.; Hagen, T.; Roehr, S.; Sidhu, K. B.

    2007-01-01

    The effective reduction of energy consumption and a reasonable treatment of resources can be achieved by minimizing a component's weight using lightweight metals. In this context, aluminum alloys play a major role. Due to their material-sided restricted formability, the mentioned aluminum materials are difficult to form. The plasticity of a material is ascertained by its maximum forming limit. It is attained, when the deformation causes mechanical damage within the material. Damage of that sort is reached more rapidly, the greater the tensile strength rate in relation to total tension rate. A promising approach of handling these low ductile, high-strength aluminum alloys within a forming process, is forming with a synchronized superposition of comprehensive stress by active media such as by controlling oil pressure. The influence of superimposed hydrostatic pressure on the flow stress was analyzed as well as the formability for different procedures at different hydrostatic pressures and temperature levels. It was observed that flow stress is independent of superimposed hydrostatic pressure. Neither the superimposed pressure has an influence on the plastic deformation, nor does a pressure dependent material hardening due to increasing hydrostatic pressure take place. The formability increases with rising hydrostatic pressure. The relative gain at room temperature and increase of the superimposed pressure from 0 to 600 bar for tested materials was at least 140 % and max. 220 %. Therefore in this paper, based on these experimental observations, it is the intended to develop a numerical simulation in order to predict ductile damage that occurs in the bulk forging process with superimposed hydrostatic pressure based Lemaitre's damage model

  18. Non-contacting "snubber bearing" for passive magnetic bearing systems

    Science.gov (United States)

    Post, Richard F

    2017-08-22

    A new non-contacting magnetic "snubber" bearing is provided for application to rotating systems such as vehicular electromechanical battery systems subject to frequent accelerations. The design is such that in the equilibrium position the drag force of the snubber is very small (milliwatts). However in a typical case, if the rotor is displaced by as little as 2 millimeters a large restoring force is generated without any physical contact between the stationary and rotating parts of the snubber bearing.

  19. Evolution of the Fermi surface of the strongly correlated f electron system under hydrostatic and uniaxial pressures

    CERN Document Server

    Aoki, H; Endo, M; Nakayama, M; Takei, H; Kimura, N; Kunii, S; Terashima, T; Uji, S; Matsumoto, T

    2002-01-01

    We report our recent developments of experimental systems for measuring the de Haas-van Alphen (dHvA) effect under hydrostatic and uniaxial pressures. The dHvA effect of CeB sub 6 has been studied under both hydrostatic and uniaxial pressures and the effects of the pressures on the electronic structure are discussed.

  20. Bears, Big and Little. Young Discovery Library Series.

    Science.gov (United States)

    Pfeffer, Pierre

    This book is written for children 5 through 10. Part of a series designed to develop their curiosity, fascinate them and educate them, this volume describes: (1) the eight species of bears, including black bear, brown bear, grizzly bear, spectacled bear, sun bear, sloth bear, polar bear, and giant panda; (2) geographical habitats of bears; (3)…

  1. Use of a high temperature hydrostatic extrusion technique for powders strengthening

    International Nuclear Information System (INIS)

    Decours, J.; Gavinet, J.; Weisz, M.

    1975-01-01

    A conventional 575 tonnes extrusion press has been modified by a device permitting the extrusion process by hydrostatic pression through a leakless mechanical set (13,000 bars maximum), from room temperature to 1,200 deg C. This new device allows: the high temperature hydrostatic extrusion for strengthening of powders, the isostatic compression of powders. Examples of realisations obtained by this process are described, including the influence of different parameters: pressure, temperature, extrusion ratio and for different materials: pure metals (iron, nickel, niobium, etc...) and alloys (stainless steel, molybdenum, niobium nickel alloys, etc...). Then, the advantages of the process are emphasized [fr

  2. Ventricular differences between hydrostatic hydrocephalus and hydrocephalus Ex Vacuo by computed tomography

    Energy Technology Data Exchange (ETDEWEB)

    LeMay, M; Hochberg, F H [Massachusetts General Hospital, Boston (USA). Radiology Dept.; Massachusetts General Hospital, Boston (USA). Dept. of Neurology; Harvard Medical School, Boston, MA (USA))

    1979-01-01

    Transaxial CT scans of 100 patients with hydrostatic hydrocephalus and 50 patients with hydrocephalus ex vacuo have been reviewed with respect to measurements of: frontal horn ratio, width of the temporal horns, width of the third ventricle, width of cerebral fissures and sulci. The diagnosis of hydrostatic hydrocephalus is probable when (a) both temporal tips are visualized and measure 3 mm or greater in width and the sylvian and interhemispheric fissures and cerebral sulci are not visible, or (b) there is visualization of temporal horn tips measuring 2 mm or greater in width and the lateral ventricles are symmetrically enlarged with the frontal horn ratio 0.50 or more.

  3. Failure behavior of nano-SiO2 fillers epoxy coating under hydrostatic pressure

    International Nuclear Information System (INIS)

    Liu Li; Cui Yu; Li Ying; Zhang Tao; Wang Fuhui

    2012-01-01

    The failure of organic coating (epoxy resin filled with 5 mass% nano-SiO 2 particles) on mild steel under high hydrostatic pressure (35 atm) has been studied compared with that under atmospheric pressure (1 atm), using impedance measurements, gravimetric testing, adhesion testing and scanning electron microscopy (SEM). The results show that high hydrostatic pressure accelerated the failure of the organic coating by promoting diffusion of water in the coating, which speeds up water spread and electrochemical reactions at the interface. The roughness of the coating and steel has been discussed from point of view of their respective fractal dimensions D fc and D fdl , as deduced from impedance measurements

  4. Simulation study of a hydrostat design for detecting underground leakage of water supply using neutron backscattering

    International Nuclear Information System (INIS)

    Kurosawa, Tadahiro; Nakamura, Takashi; Suzuki, Takashi; Okano, Yasuhiro; Chisaka, Haruo

    1998-01-01

    We have embarked upon the development of a new detection method for underground water leakage using a neutron backscattering system. We have estimated the performance capabilities of such a system using Monte Carlo simulation. It is indicated that a leak which results in 40% water content in the surrounding soils could be detected at depths of up to 40 cm from the surface to the center of the source of leakage. This new detection system could be useful as a hydrostat of underground water supply in noisy areas such as Tokyo, in place of presently-used hydrostats which are based on detection of changes in sound

  5. Ultrasound-guided hydrostatic reduction of intestinal intussusception: description of three cases

    Directory of Open Access Journals (Sweden)

    Martha Hanemann Kim

    2008-09-01

    Full Text Available With the objective of reporting the technique of ultrasound-guided hydrostatic reduction of intestinal intussusception, three cases with confirmed diagnosis of the disease submitted to reduction with this technique are described. All cases had successful reductions with no complications. One patient experienced a recurrence of the invagination eight days after treatment, which was surgically corrected. The technique of hydrostatic reversal of intestinal intussusception guided by ultrasound may be used in place of the conventional barium enema, since it is a minimally invasive and safe method, with high rates of success and few complications.

  6. Evolution of transverse piezoelectric response of lead zirconate titanate ceramics under hydrostatic pressure

    International Nuclear Information System (INIS)

    Li Fei; Xu Zhuo; Wei Xiaoyong; Gao Junjie; Zhang, Chonghui; Yao Xi; Jin Li

    2009-01-01

    The piezoelectric properties of 31-mode resonators of lead zirconate titanate ceramics under hydrostatic pressure from 0.1 to 325 MPa were evaluated by a fitting method, in which mechanical loss was taken into account. Our results based on the fitting method showed a hydrostatic pressure independent tendency of the piezoelectric coefficient and the electromechanical coupling factor because the adopted PZT ceramic can be considered as a linear system in our experiment, while two misleading tendencies of piezoelectric coefficient were obtained based on the resonance method when ignoring the contribution of the mechanical loss. (fast track communication)

  7. Moessbauer investigation of SnO under hydrostatic pressure up to 41 kbar

    International Nuclear Information System (INIS)

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

    1979-01-01

    Influence of hydrostatic pressure, P, on the probability of recoilless absorption, f, relative absorption line position, ΔE, and quadrupole splitting, ΔEsub(Q), of Moessbauer spectrum are experimentally determined. Results of a Moessbauer study of SnO point to a linear increase of f, decreases of the electron density at the tin nucleus and increases Esub(Q) with increasing P. The phase transition in SnO discovered earlier in non hydrostatic conditions is not detected. This fact is used to make conclusion that it is necessary to take into account shearing stresses for this phase transition. (author)

  8. Influence of deformation conditions on texture formation and ductility in titanium alloys under hydrostatic pressure

    International Nuclear Information System (INIS)

    Dekun, A.M.; Kushakevich, S.A.; Adamesku, R.A.; Khmelinin, Yu.F.; Beresnev, B.I.; Shishmintsev, V.F.

    1982-01-01

    The influence of hot pressing parameters on microstructure, texture and mechanical properties of bars from titanium alloys VT1-0, VT5-1, (α-alloys) and VT3-1 (α+ν-alloy) has been investigated. Mechanical testing of samples has been performed under hydrostatic pressure from 200 to 800 MPa. It is shown that the temperature, deformation degree and type of the structure obtained exert a slight effect on mechanical properties of bars. The texture heterogeneity is more pronounced in α-alloys. It has been found that hydrostatic pressure during sample tensile testing improves their ductility characteristics

  9. Strain measurement and analysis for the RPV of Qinshan NPP (unit I) at primary system hydrostatic test

    International Nuclear Information System (INIS)

    Qu Jiadi; Wang Peizhu; Xie Shiqiu; Chen Renchang; Sheng Xianke; Dou Yikang; Zhao Weiliang

    1994-01-01

    Hydrostatic test for RPV (Reactor Pressure Vessel) is not only a means to inspect the vessels and the associated systems but also an important way to verify the results of mechanical analysis. The loading obtained by measurement is useful for the establishment of loading spectrum. Some discussions on the shop hydrostatic test planning for the RPV of Qinshan NPP (Nuclear Power Plant) performed in Japan are presented. Comparisons between the results of hydrostatic test provided by vendor and those of primary system hydrostatic test conducted at Qinshan Site are also given. Some data obtained at Qinshan Site such as actual loading and technical data of the stud-bolt, are listed. The results of measurement for the flange rotation, important for the sealing characteristics of RPV, are specifically discussed. The authors point out some of the mistakes in the results of the shop hydrostatic test

  10. A Statistical Study on the Effect of Hydrostatic Pressure on Metastable Pitting Corrosion of X70 Pipeline Steel.

    Science.gov (United States)

    Yang, Zixuan; Kan, Bo; Li, Jinxu; Qiao, Lijie; Volinsky, Alex A; Su, Yanjing

    2017-11-14

    Hydrostatic pressure effects on pitting initiation and propagation in X70 steel are investigated by evaluating metastable pitting probability using electrochemical methods and immersion corrosion tests in containing chlorine ion solution. Potentiodynamic tests indicated that hydrostatic pressure can decrease the breakdown potential and lead to a reduced transpassivity region. Metastable test results revealed that hydrostatic pressure can increase metastable pitting formation frequency and promote stabilization of metastable pitting growth. Electrochemical impedance spectroscopy (EIS) results indicate that Hydrostatic pressure decreases the charge transfer resistance and increases the dissolution rate within the cavities. Corrosion test results also indicated that pitting initiation and propagation are accelerated by hydrostatic pressure. Result validity was verified by evaluating metastable pitting to predict pitting corrosion resistance.

  11. 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 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.

  12. The effect of hydrostatic pressure on the creep life of a 2.25% Cr1% Mo Steel

    International Nuclear Information System (INIS)

    Lonsdale, D.; Flewitt, P.E.J.

    1979-01-01

    The effect of superimposed hydrostatic pressures on the creep life of a 2.25% Cr 1% Mo steel, with a bainitic microstructure, is examined. Creep tests have been carried out at 923K with uniaxial stresses in the range 55 to 80 MPa and superimposed hydrostatic pressures up to 35 MPa. Optical and scanning electron microscopy have been used to evaluate the contribution of the hydrostatic stress to grain boundary cavitation. Increasing the hydrostatic pressure for a given uniaxial stress suppresses cavitation, but little changes the secondary creep rate, thereby excending the creep life. Furthermore, the time to failure depends on both the applied uniaxial stress and the hydrostatic pressure and not simply the principal stress. (orig.) [de

  13. Water-bearing explosive compositions

    Energy Technology Data Exchange (ETDEWEB)

    Gay, G M

    1970-12-21

    An explosive water-bearing composition, with high detonation velocity, comprises a mixture of (1) an inorganic oxidizer salt; (2) nitroglycerine; (3) nitrocellulose; (4) water; and (5) a water thickening agent. (11 claims)

  14. Failure analysis of superconducting bearings

    Energy Technology Data Exchange (ETDEWEB)

    Rastogi, Amit; Campbell, A M; Coombs, T A [Department of Engineering, University of Cambridge, Cambridge CB2 1PZ (United Kingdom)

    2006-06-01

    The dynamics of superconductor bearings in a cryogenic failure scenario have been analyzed. As the superconductor warms up, the rotor goes through multiple resonance frequencies, begins to slow down and finally touches down when the superconductor goes through its transition temperature. The bearing can be modelled as a system of springs with axial, radial and cross stiffness. These springs go through various resonant modes as the temperature of the superconductor begins to rise. We have presented possible explanations for such behavio0008.

  15. Superconducting composite for magnetic bearings

    International Nuclear Information System (INIS)

    Rigney, T.K. II.

    1995-01-01

    A composite includes granules of Type II superconducting material and granules of rare-earth permanent magnets that are distributed in a binder. The composite is a two-phase structure that combines the properties of the superconductor and magnets with the flexibility and toughness of a polymeric material. A bearing made from this composite has the load capacity and stiffness of a permanent magnet bearing with added stability from a Type II superconducting material. 7 figs

  16. Effect of high hydrostatic pressure on the physiology of Manila mango.

    Science.gov (United States)

    Vargas-Ortiz, M A; De la Cruz-Medina, J; de Los Monteros, J J Espinosa; Oliart-Ros, R M; Rebolledo-Martinez, A; Ramírez, J A; García, H S

    2013-06-01

    Manila mangoes (Mangifera indica L.) have sensory characteristics that make them attractive for consumption as a fresh fruit. A large portion of the annual yield of this fruit is infested by the Mexican fruit fly (Anastrepha ludens), adversely impacting the quality of the crop. Hence, it is necessary to develop economically viable postharvest treatments to reduce the damage caused by this insect. Currently, high hydrostatic pressures are used to guarantee the safety of many processed foods. The objective of this work was to assess the effects of high hydrostatic pressure on mangoes at their physiological maturity. High hydrostatic pressures were applied to mangoes at three levels: 50, 100 and 200 megapascals applied for four different time periods (0, 5, 10 and 20 min). Physiologically mature mangoes were more resistant to changes in response to the pressure of 50 MPa. Reduction of physiological activity by application of high hydrostatic pressure opens a new avenue for the research on treatments intended to enhance preservation of whole fresh fruit.

  17. Corrections for hydrostatic atmospheric models: radii and effective temperatures of Wolf Rayet stars

    International Nuclear Information System (INIS)

    Loore, C. de; Hellings, P.; Lamers, H.J.G.L.M.

    1982-01-01

    With the assumption of plane-parallel hydrostatic atmospheres, used generally for the computation of evolutionary models, the radii of WR stars are seriously underestimated. The true atmospheres may be very extended, due to the effect of the stellar wind. Instead of these hydrostatic atmospheres the authors consider dynamical atmospheres adopting a velocity law. The equation of the optical depth is integrated outwards using the equation of continuity. The ''hydrostatic'' radii are to be multiplied with a factor 2 to 8, and the effective temperatures with a factor 0.8 to 0.35 when Wolf Rayet characteristics for the wind are considered, and WR mass loss rates are used. With these corrections the effective temperatures of the theoretical models, which are helium burning Roche lobe overflow remnants, range between 30,000 K and 50,000 K. Effective temperatures calculated in the hydrostatic hypothesis can be as high as 150,000 K for helium burning RLOF-remnants with WR mass loss rates. (Auth.)

  18. 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.

  19. In situ study starch gelatinization under ultra-high hydrostatic pressure using synchrotron SAXS

    KAUST Repository

    Yang, Zhi; Gu, Qinfen; Lam, Elisa; Tian, Feng; Chaieb, Saharoui; Hemar, Yacine

    2015-01-01

    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

  20. Supercooled dynamics of glass-forming liquids and polymers under hydrostatic pressure

    Energy Technology Data Exchange (ETDEWEB)

    Roland, C M [Naval Research Laboratory, Chemistry Division, Code 6120, Washington, DC 20375-5342 (United States); Hensel-Bielowka, S [Institute of Physics, Silesian University, ul. Uniwersytecka 4, 40-007 Katowice (Poland); Paluch, M [Institute of Physics, Silesian University, ul. Uniwersytecka 4, 40-007 Katowice (Poland); Casalini, R [Naval Research Laboratory, Chemistry Division, Code 6120, Washington, DC 20375-5342 (United States); Chemistry Department, George Mason University, Fairfax, VA 22030 (United States)

    2005-06-01

    An intriguing problem in condensed matter physics is understanding the glass transition, in particular the dynamics in the equilibrium liquid close to vitrification. Recent advances have been made by using hydrostatic pressure as an experimental variable. These results are reviewed, with an emphasis in the insight provided into the mechanisms underlying the relaxation properties of glass-forming liquids and polymers.

  1. LONG TERM STABILITY STUDY AT FNAL AND SLAC USING BINP DEVELOPED HYDROSTATIC LEVEL SYSTEM

    Energy Technology Data Exchange (ETDEWEB)

    Seryi, Andrei

    2003-05-28

    Long term ground stability is essential for achieving the performance goals of the Next Linear Collider. To characterize ground motion on relevant time scales, measurements have been performed at three geologically different locations using a hydrostatic level system developed specifically for these studies. Comparative results from the different sites are presented in this paper.

  2. Demonstration of Hydrostatic Paradox with Plastic Bottles and LabQuest Vernier

    Science.gov (United States)

    Kodejška, Cenek

    2018-01-01

    This work focuses on the experimental demonstration of the hydrostatic paradox using simple tools in the form of plastic bottles and plastic syringes with a thread. For the evaluation of the results obtained the data logger Lab Quest Vernier was used. The construction of the device is presented in the first part of this paper. The second part…

  3. Depth-Averaged Non-Hydrostatic Hydrodynamic Model Using a New Multithreading Parallel Computing Method

    Directory of Open Access Journals (Sweden)

    Ling Kang

    2017-03-01

    Full Text Available Compared to the hydrostatic hydrodynamic model, the non-hydrostatic hydrodynamic model can accurately simulate flows that feature vertical accelerations. The model’s low computational efficiency severely restricts its wider application. This paper proposes a non-hydrostatic hydrodynamic model based on a multithreading parallel computing method. The horizontal momentum equation is obtained by integrating the Navier–Stokes equations from the bottom to the free surface. The vertical momentum equation is approximated by the Keller-box scheme. A two-step method is used to solve the model equations. A parallel strategy based on block decomposition computation is utilized. The original computational domain is subdivided into two subdomains that are physically connected via a virtual boundary technique. Two sub-threads are created and tasked with the computation of the two subdomains. The producer–consumer model and the thread lock technique are used to achieve synchronous communication between sub-threads. The validity of the model was verified by solitary wave propagation experiments over a flat bottom and slope, followed by two sinusoidal wave propagation experiments over submerged breakwater. The parallel computing method proposed here was found to effectively enhance computational efficiency and save 20%–40% computation time compared to serial computing. The parallel acceleration rate and acceleration efficiency are approximately 1.45% and 72%, respectively. The parallel computing method makes a contribution to the popularization of non-hydrostatic models.

  4. Effect of hydrostatic and uniaxial pressure on structural and magnetic transitions in TbNiAl

    Czech Academy of Sciences Publication Activity Database

    Kaštil, Jiří; Klicpera, M.; Prchal, J.; Míšek, Martin; Prokleška, J.; Javorský, P.

    2014-01-01

    Roč. 585, Feb (2014), s. 98-102 ISSN 0925-8388 Institutional support: RVO:68378271 Keywords : magnetic ordering * electrical resistivity * hydrostatic pressure * structural transition Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 2.999, year: 2014

  5. Mechanical stability of Ni and Ir under hydrostatic and uniaxial loading

    Czech Academy of Sciences Publication Activity Database

    Řehák, Petr; Černý, Miroslav; Šob, Mojmír

    2015-01-01

    Roč. 23, č. 5 (2015), art. n. 055010 ISSN 0965-0393 R&D Projects: GA ČR(CZ) GAP108/12/0311 Institutional support: RVO:68081723 Keywords : ab initio calculations * elastic stability * phonon instability * theoretical strength * hydrostatic loading * uniaxial loading Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 1.859, year: 2015

  6. Nuclear Technology. Course 26: Nondestructive Examination (NDE) Techniques I. Module 26-3, Hydrostatic Tests.

    Science.gov (United States)

    Pelton, Rick; Espy, John

    This third in a series of seven modules for a course titled Nondestructive Examination (NDE) Techniques I describes the principles and practices associated with hydrostatic testing. The module follows a typical format that includes the following sections: (1) introduction, (2) module prerequisites, (3) objectives, (4) notes to instructor/student,…

  7. Thermal fluid-solid interaction model and experimental validation for hydrostatic mechanical face seals

    Science.gov (United States)

    Huang, Weifeng; Liao, Chuanjun; Liu, Xiangfeng; Suo, Shuangfu; Liu, Ying; Wang, Yuming

    2014-09-01

    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.

  8. Inactivation of human norovirus in contaminated oysters and clams by high-hydrostatic pressure

    Science.gov (United States)

    Human norovirus (NoV) is the most frequent causative agent of foodborne disease associated with shellfish consumption. In this study, the effect of high-hydrostatic pressure (HHP) on inactivation of NoV was determined. Genogroup I.1 (GI.1) or Genogroup II.4 (GII.4) NoV were inoculated into oyster ho...

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

    NARCIS (Netherlands)

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

    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

  10. 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...

  11. Human norovirus inactivation in oysters by high hydrostatic pressure processing: A randomized double-blinded study

    Science.gov (United States)

    This randomized, double-blinded, clinical trial assessed the effect of high hydrostatic pressure processing (HPP) on genogroup I.1 human norovirus (HuNoV) inactivation in virus-seeded oysters when ingested by subjects. The safety and efficacy of HPP treatments were assessed in three study phases wi...

  12. 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…

  13. Effect of Pulsed Ultraviolet Light and High Hydrostatic Pressure on the Antigenicity of Almond Protein Extracts.

    Science.gov (United States)

    The efficacy of pulsed ultraviolet light (PUV) and high hydrostatic pressure (HHP) on reducing the IgE binding to the almond extracts, was studied using SDS-PAGE, Western Blot, and ELISA probed with human plasma containing IgE antibodies to almond allergens, and a polyclonal antibody against almond ...

  14. 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.

  15. Effect of high hydrostatic pressure processing on the background microbial loads and quality of cantaloupe puree

    Science.gov (United States)

    The objective of this study was to investigate and evaluate the effects of high hydrostatic pressure (HHP) applied to cantaloupe puree (CP) on microbial loads and product quality during storage for 10 days at 4 degrees C. Freshly prepared, double sealed and double bagged CP (ca. 5 g) was pressure tr...

  16. Transcriptomics Reveal Several Gene Expression Patterns in the Piezophile Desulfovibrio hydrothermalis in Response to Hydrostatic Pressure

    Science.gov (United States)

    Amrani, Amira; Bergon, Aurélie; Holota, Hélène; Tamburini, Christian; Garel, Marc; Ollivier, Bernard; Imbert, Jean; Dolla, Alain; Pradel, Nathalie

    2014-01-01

    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. PMID:25215865

  17. 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

  18. MRI measurements of intracranial pressure in the upright posture: The effect of the hydrostatic pressure gradient.

    Science.gov (United States)

    Alperin, Noam; Lee, Sang H; Bagci, Ahmet M

    2015-10-01

    To add the hydrostatic component of the cerebrospinal fluid (CSF) pressure to magnetic resonance imaging (MRI)-derived intracranial pressure (ICP) measurements in the upright posture for derivation of pressure value in a central cranial location often used in invasive ICP measurements. Additional analyses were performed using data previously collected from 10 healthy subjects scanned in supine and sitting positions with a 0.5T vertical gap MRI scanner (GE Medical). Pulsatile blood and CSF flows to and from the brain were quantified using cine phase-contrast. Intracranial compliance and pressure were calculated using a previously described method. The vertical distance between the location of the CSF flow measurement and a central cranial location was measured manually in the mid-sagittal T1 -weighted image obtained in the upright posture. The hydrostatic pressure gradient of a CSF column with similar height was then added to the MR-ICP value. After adjustment for the hydrostatic component, the mean ICP value was reduced by 7.6 mmHg. Mean ICP referenced to the central cranial level was -3.4 ± 1.7 mmHg compared to the unadjusted value of +4.3 ± 1.8 mmHg. In the upright posture, the hydrostatic pressure component needs to be added to the MRI-derived ICP values for compatibility with invasive ICP at a central cranial location. © 2015 Wiley Periodicals, Inc.

  19. A class-A GPCR solubilized under high hydrostatic pressure retains its ligand binding ability

    Science.gov (United States)

    The effect of high hydrostatic pressure (HHP) on the solubilization of a class-A G protein-coupled receptor, the silkmoth pheromone biosynthesis-activating neuropeptide receptor (PBANR), was investigated. PBANR was expressed in expresSF+ insect cells as a C-terminal fusion protein with EGFP. The mem...

  20. Self-stabilization of untransformed austenite by hydrostatic pressure via martensitic transformation

    International Nuclear Information System (INIS)

    Nakada, Nobuo; Ishibashi, Yuji; Tsuchiyama, Toshihiro; Takaki, Setsuo

    2016-01-01

    For improving the understanding of austenite stability in steel, hydrostatic pressure in untransformed austenite that is generated via martensitic transformation was evaluated from macro- and micro-viewpoints, and its effect on austenite stability was investigated in a Fe-27%Ni austenitic alloy. X-ray diffractometry revealed that the lattice parameter of untransformed austenite is continuously decreased via martensitic transformation only when martensite becomes the dominant phase in the microstructure. This suggests that the untransformed austenite is isotropically compressed by the surrounding martensite grains, i.e., hydrostatic pressure is generated in untransformed austenite dynamically at a later stage of martensitic transformation. On the other hand, microscopic strain mapping using the electron backscatter diffraction technique indicated that a finer untransformed austenite grain has a higher hydrostatic pressure, while a high density of dislocations is also introduced in untransformed austenite near the austenite/martensite interface because of lattice-invariant shear characterized by non-thermoelastic martensitic transformation. Furthermore, it was experimentally demonstrated that the hydrostatic pressure stabilizes the untransformed austenite; however, the austenite stabilization effect alone is not large enough to fully explain a large gap between martensite start and finish temperatures in steel.

  1. Hydrostatic-pressure and uniaxial-strain experiments for controlling the spin-Peierls transition

    International Nuclear Information System (INIS)

    Mito, Masaki; Deguchi, Hiroyuki; Fujita, Wataru; Kondo, Ryusuke; Kagoshima, Seiichi

    2010-01-01

    The spin-Peierls (SP) system is considered to be a quantum spin system strongly coupled with the lattice. We have succeeded in controlling SP transition by applying hydrostatic pressure and/or uniaxial strain. The observed phenomenon could be a typical example for understanding the SP transition based on the Hamiltonian. (author)

  2. 49 CFR 229.69 - Side bearings.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Side bearings. 229.69 Section 229.69....69 Side bearings. (a) Friction side bearings with springs designed to carry weight may not have more than 25 percent of the springs in any one nest broken. (b) Friction side bearings may not be run in...

  3. Piezoelectric Performance and Hydrostatic Parameters of Novel 2-2-Type Composites.

    Science.gov (United States)

    Topolov, Vitaly Yu; Bowen, Christopher R; Krivoruchko, Andrey V

    2017-10-01

    This paper provides a detailed study of the structure-piezoelectric property relationships and the hydrostatic response of 2-2-Type composites based on relaxor-ferroelectric 0.72 Pb (Mg 1/3 Nb 2/3 )O 3 -0.28PbTiO 3 single crystal (SC) material. Type I layers in the composite system are represented by a single-domain [111]-poled SC. Changes in the orientation of the crystallographic axes in the Type I layer are undertaken to determine the maximum values of the hydrostatic piezoelectric coefficients d h ∗ , g h ∗ , and e h ∗ , and squared figure of merit d h ∗ g h ∗ of the composite. The Type II layers are a 0-3 composite whereby inclusions of modified PbTiO 3 ceramic are distributed in a polymer matrix. A new effect is described for the first time due to the impact of anisotropic elastic properties of the Type II layers on the hydrostatic piezoelectric response that is coupled with the polarization orientation effect in the Type I layers. Large hydrostatic parameters g h ∗ ≈ 300 -400 mV · m/N, e h ∗ ≈ 40 -45 C/ [Formula: see text], and d h ∗ g h ∗  ∼ 10 -11 Pa -1 are achieved in the composite based on the 0.72 Pb(Mg 1/3 Nb 2/3 )O 3 -0.28PbTiO 3 SC. Examples of the large piezoelectric anisotropy ( |d 33 ∗ /d 3f ∗ | ≥ 5 or | g 33 ∗ /g 3f ∗ | ≥ 5 ) are discussed. The hydrostatic parameters of this novel compositesystem are compared to those of conventional 2-2 piezocomposites.

  4. Influence of hydrostatic pressure on intracoronary indices of stenosis severity in vivo.

    Science.gov (United States)

    Härle, Tobias; Luz, Mareike; Meyer, Sven; Vahldiek, Felix; van der Harst, Pim; van Dijk, Randy; Ties, Daan; Escaned, Javier; Davies, Justin; Elsässer, Albrecht

    2018-03-01

    An influence of hydrostatic pressure on intracoronary indices of stenosis severity in vitro was recently reported. We sought to analyze the influence of hydrostatic pressure, caused by the height difference between the distal and proximal pressure sensor after guidewire positioning in the interrogated vessel, on intracoronary pressure measurements in vivo. In 30 coronary stenoses, intracoronary pressure measurements were performed in supine, left, and right lateral patient position. Height differences between the distal and proximal pressure sensor were measured by blinded observers. Measurement results of the position with the highest ("high") and lowest height difference ("low") were compared. In group "high", all measured indices were higher: mean difference of fractional flow reserve (FFR) 0.045 (SD 0.033, 95% CI 0.033-0.057, p hydrostatic pressure to the distal coronary pressures of the control group abolished the differences: corrected ∆FFR - 0.006 (SD 0.027, 95% CI - 0.015 to 0.004, p = 0.26), corrected ∆Pd/Pa - 0.008 (SD 0.03, 95% CI - 0.019 to 0.003, p = 0.18). Adjustment for hydrostatic pressure of FFR values in a standard supine position increased all values in anterior vessels and decreased all values in posterior vessels. The mean changes of FFR due to adjustment were: LAD - 0.048 (SD 0.016), CX 0.02 (SD 0.009), RCA 0.02 (SD 0.021). Dichotomous severity classification changed in 12.9% of stenoses. The study demonstrates a relevant influence of hydrostatic pressure on intracoronary indices of stenosis severity in vivo, caused by the height differences between distal and proximal pressure sensor.

  5. Effect of high-hydrostatic pressure and moderate-intensity pulsed electric field on plum.

    Science.gov (United States)

    García-Parra, J; González-Cebrino, F; Delgado-Adámez, J; Cava, R; Martín-Belloso, O; Élez-Martínez, P; Ramírez, R

    2018-03-01

    Moderate intensity pulse electric fields were applied in plum with the aim to increase bioactive compounds content of the fruit, while high-hydrostatic pressure was applied to preserve the purées. High-hydrostatic pressure treatment was compared with an equivalent thermal treatment. The addition of ascorbic acid during purée manufacture was also evaluated. The main objective of this study was to assess the effects on microorganisms, polyphenoloxidase, color and bioactive compounds of high-hydrostatic pressure, or thermal-processed plum purées made of moderate intensity pulse electric field-treated or no-moderate intensity pulse electric field-treated plums, after processing during storage. The application of moderate intensity pulse electric field to plums slightly increased the levels of anthocyanins and the antioxidant activity of purées. The application of Hydrostatic-high pressure (HHP) increased the levels of bioactive compounds in purées, while the thermal treatment preserved better the color during storage. The addition of ascorbic acid during the manufacture of plum purée was an important factor for the final quality of purées. The color and the bioactive compounds content were better preserved in purées with ascorbic acid. The no inactivation of polyphenoloxidase enzyme with treatments applied in this study affected the stability purées. Probably more intense treatments conditions (high-hydrostatic pressure and thermal treatment) would be necessary to reach better quality and shelf life during storage.

  6. 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.

  7. An efficient semi-implicit method for three-dimensional non-hydrostatic flows in compliant arterial vessels.

    Science.gov (United States)

    Fambri, Francesco; Dumbser, Michael; Casulli, Vincenzo

    2014-11-01

    Blood flow in arterial systems can be described by the three-dimensional Navier-Stokes equations within a time-dependent spatial domain that accounts for the elasticity of the arterial walls. In this article, blood is treated as an incompressible Newtonian fluid that flows through compliant vessels of general cross section. A three-dimensional semi-implicit finite difference and finite volume model is derived so that numerical stability is obtained at a low computational cost on a staggered grid. The key idea of the method consists in a splitting of the pressure into a hydrostatic and a non-hydrostatic part, where first a small quasi-one-dimensional nonlinear system is solved for the hydrostatic pressure and only in a second step the fully three-dimensional non-hydrostatic pressure is computed from a three-dimensional nonlinear system as a correction to the hydrostatic one. The resulting algorithm is robust, efficient, locally and globally mass conservative, and applies to hydrostatic and non-hydrostatic flows in one, two and three space dimensions. These features are illustrated on nontrivial test cases for flows in tubes with circular or elliptical cross section where the exact analytical solution is known. Test cases of steady and pulsatile flows in uniformly curved rigid and elastic tubes are presented. Wherever possible, axial velocity development and secondary flows are shown and compared with previously published results. Copyright © 2014 John Wiley & Sons, Ltd.

  8. A stochastic analysis of the effect of hydrostatic pressure on the pit corrosion of Fe-20Cr alloy

    International Nuclear Information System (INIS)

    Zhang Tao; Yang Yange; Shao Yawei; Meng, Guozhe; Wang, Fuhui

    2009-01-01

    The effect of hydrostatic pressure on the pit corrosion behavior of Fe-20Cr alloy was investigated in 3.5% NaCl solution by means of potentiodynamic polarization and potentiostatic technology, and the experiment data was analyzed based on stochastic theory. With the increase of hydrostatic pressure, the pit corrosion resistance of Fe-20Cr alloy was deteriorated, which was distinguished by the decrease of critical pit potential (E cirt ) and the increase of passive current density. The results also demonstrated that there exist two effects of hydrostatic pressure on the corrosion behavior of Fe-20Cr alloy: (1) the pit generation rate was evidently increased compared to that under lower hydrostatic pressure, and the metastable pits become faster and larger. However, it seemed that pit generation mechanism shows no hydrostatic pressure dependence; (2) the probability of pit growth increased with the increase of hydrostatic pressure, which implied that the metastable pit on Fe-20Cr alloy exhibited higher probability to become larger pit cavity during shorter time interval than that under lower hydrostatic pressure.

  9. Superconductor bearings, flywheels and transportation

    International Nuclear Information System (INIS)

    Werfel, F N; Floegel-Delor, U; Rothfeld, R; Riedel, T; Goebel, B; Wippich, D; Schirrmeister, P

    2012-01-01

    This paper describes the present status of high temperature superconductors (HTS) and of bulk superconducting magnet devices, their use in bearings, in flywheel energy storage systems (FESS) and linear transport magnetic levitation (Maglev) systems. We report and review the concepts of multi-seeded REBCO bulk superconductor fabrication. The multi-grain bulks increase the averaged trapped magnetic flux density up to 40% compared to single-grain assembly in large-scale applications. HTS magnetic bearings with permanent magnet (PM) excitation were studied and scaled up to maximum forces of 10 kN axially and 4.5 kN radially. We examine the technology of the high-gradient magnetic bearing concept and verify it experimentally. A large HTS bearing is tested for stabilizing a 600 kg rotor of a 5 kWh/250 kW flywheel system. The flywheel rotor tests show the requirement for additional damping. Our compact flywheel system is compared with similar HTS–FESS projects. A small-scale compact YBCO bearing with in situ Stirling cryocooler is constructed and investigated for mobile applications. Next we show a successfully developed modular linear Maglev system for magnetic train operation. Each module levitates 0.25t at 10 mm distance during one-day operation without refilling LN 2 . More than 30 vacuum cryostats containing multi-seeded YBCO blocks are fabricated and are tested now in Germany, China and Brazil.

  10. Noise estimation of oil lubricated journal bearings

    International Nuclear Information System (INIS)

    Rho, Byoung Hoo; Kim, Kyung Woong

    2003-01-01

    Noise estimating procedures of oil lubricated journal bearings are presented. Nonlinear analysis of rotor-bearing system including unbalance mass of the rotor is performed in order to obtain acoustical properties of the bearing. Acoustical properties of the bearing are investigated through frequency analysis of the pressure fluctuation of the fluid film calculated from the nonlinear analysis. Noise estimating procedures presented in this paper could aid in the evaluation and understanding of acoustical properties of oil lubricated journal bearings

  11. Changes in plain bearing technology

    CERN Document Server

    Koring, Rolf

    2012-01-01

    A unique fusion of theoretical and practical knowledge, Changes in Plain Bearing Technology, by Rolf Koring, covers a meaningful range of expertise in this field.Drawing from years of experience in design development, materials selection, and their correlation to real-life part failure, this title, co-published by SAE International and expert Verlag (Germany), concentrates on hydrodynamic bearings lined with white metals, also known as Babbits.Written under the assumption that even the most mature body of knowledge can be revisited and improved, Changes in Plain Bearing Technology is a courageous and focused approach to questioning accepted test results and looking at alternative material compounds, and their application suitability.The process, which leads to innovative answers on how the technology is transforming itself to respond to new market requirements, shows how interdisciplinary thinking can recognize new potential in long-established industrial modus operandi.Tackling the highly complex issue of co...

  12. 'Dodo' and 'Baby Bear' Trenches

    Science.gov (United States)

    2008-01-01

    NASA's Phoenix Mars Lander's Surface Stereo Imager took this image on Sol 11 (June 5, 2008), the eleventh day after landing. It shows the trenches dug by Phoenix's Robotic Arm. The trench on the left is informally called 'Dodo' and was dug as a test. The trench on the right is informally called 'Baby Bear.' The sample dug from Baby Bear will be delivered to the Phoenix's Thermal and Evolved-Gas Analyzer, or TEGA. The Baby Bear trench is 9 centimeters (3.1 inches) wide and 4 centimeters (1.6 inches) deep. The Phoenix Mission is led by the University of Arizona, Tucson, on behalf of NASA. Project management of the mission is by NASA's Jet Propulsion Laboratory, Pasadena, Calif. Spacecraft development is by Lockheed Martin Space Systems, Denver.

  13. The effect of ascitic fluid hydrostatic pressure on albumin extravasation rate in patients with cirrhosis of the liver

    DEFF Research Database (Denmark)

    Henriksen, Jens Henrik Sahl; Parving, H H; Lassen, N A

    1981-01-01

    and pigs with posthepatic portal hypertension and intraperitoneally instilled fluid were studied before and after abdominal paracentesis in order to evaluate the effect of ascitic fluid hydrostatic pressure on the transvascular escape rate of albumin. TERalb of the ascitic patients (n = 6) were on average......, TERalb rose significantly to an average of 24.3% IVMalb.h-1. The increased albumin extravasation rate after removal of ascites is best explained by an increased sinusoidal-tissue pressure difference caused by a decreased hydrostatic fluid pressure in the liver interstitium (portal and subcapsular spaces......) due to the hydrostatic effect of the removed ascitic fluid....

  14. Investigation of Bragg reflections in α NbDsub(x) under hydrostatic pressure by γ ray diffraction

    International Nuclear Information System (INIS)

    Blaschko, O.; Klemencic, R.; Weinzierl, P.; Eder, O.J.

    1978-01-01

    Bragg reflections of NbDsub(x) single crystals in the α phase were studied under hydrostatic pressure using γ ray diffraction. The integrated intensity of the (211) reflection decreases by - 1.5 +- 0.2%/kbar and - 0.7 +- 0.1%/kbar in NbDsub(0.04) and NbDsub(0.02) respectively. The (200), (110) and (222) reflections show no change of intensity under hydrostatic pressure. In a pure Nb crystal no decrease of the intensity of the (211) reflection was found under hydrostatic pressure. (author)

  15. Experience with Sonogram-guided hydrostatic reduction of Intussusception in Children in South-West Nigeria.

    Science.gov (United States)

    Ogundoyin, Oo; Lawal, Ta; Olulana, DI; Atalabi, Om

    2013-04-01

    Intussusception is a common cause of intestinal obstruction in young children. The diagnosis and treatment of intussusception has evolved over the years with ultrasound being the first choice imaging technique and a major player in the non-operative reduction of intussusception owing to its advantage of reduced morbidity and non-exposure to ionizing radiation when compared to other modalities of treatment. Aim & Objectives: The aim of this study was to evaluate the efficiency of ultrasound guided hydrostatic reduction in the management of intussusception in children and assess the predictors of reducibility. A prospective study of all infants and children who presented with uncomplicated intussusception was conducted between January, 2005 and September, 2013. The diagnosis of intussusception was made clinically and this was confirmed by an abdominal ultrasonography. Ultrasound guided hydrostatic reduction of intussusception was performed on the selected patients after they were adequately resuscitated. Failed reduction was abandoned in favour of operative reduction in some patients. Data collected included the age of the patients, duration of symptoms and the outcomes of the procedure and these were analyzed. Eighty-four patients with intussusception were treated over this period, 36(42.9%) patients were found suitable for hydrostatic reduction of intussusception. Twenty-four(66.7%) patients presented within 48 hours of onset of symptoms. Twenty-one(58.3%) patients had successful hydrostatic reduction of intussusception while 15(41.7%) patients had failed reduction. The procedure was successful in majority (58%) of the patients under the age of 1 year and one of the three (33%) patients older than one year. Hydrostatic reduction of intussusception was successful in 14 out of 24 patients (58.3%) who presented within 48 hours of onset of symptoms. Hydrostatic reduction of intussusception under ultrasound guidance is an effective and useful conservative method of

  16. The correct "ball bearings" data.

    Science.gov (United States)

    Caroni, C

    2002-12-01

    The famous data on fatigue failure times of ball bearings have been quoted incorrectly from Lieblein and Zelen's original paper. The correct data include censored values, as well as non-fatigue failures that must be handled appropriately. They could be described by a mixture of Weibull distributions, corresponding to different modes of failure.

  17. Little Bear Fire Summary Report

    Science.gov (United States)

    Sarah McCaffrey; Melanie Stidham; Hannah. Brenkert-Smith

    2013-01-01

    In June 2012, immediately after the Little Bear Fire burned outside Ruidoso, New Mexico, a team of researchers interviewed fire managers, local personnel, and residents to understand perceptions of the event itself, communication, evacuation, and pre-fire preparedness. The intensity of fire behavior and resulting loss of 242 homes made this a complex fire with a...

  18. Satellite monitoring of black bear.

    Science.gov (United States)

    Craighead, J. J.; Craighead, F. C., Jr.; Varney, J. R.; Cote, C. E.

    1971-01-01

    Description of a feasibility experiment recently performed to test the use of a satellite system for telemetering environmental and physiological data from the winter den of a 'hibernating' black bear, Ursus americanus. The instrumentation procedure and evaluations of the equipment performance and sensory data obtained are discussed in detail.

  19. Genomic evidence of geographically widespread effect of gene flow from polar bears into brown bears

    OpenAIRE

    Cahill, James A; Stirling, Ian; Kistler, Logan; Salamzade, Rauf; Ersmark, Erik; Fulton, Tara L; Stiller, Mathias; Green, Richard E; Shapiro, Beth

    2015-01-01

    © 2014 The Authors. Molecular Ecology Published by John Wiley & Sons Ltd. Polar bears are an arctic, marine adapted species that is closely related to brown bears. Genome analyses have shown that polar bears are distinct and genetically homogeneous in comparison to brown bears. However, these analyses have also revealed a remarkable episode of polar bear gene flow into the population of brown bears that colonized the Admiralty, Baranof and Chichagof islands (ABC islands) of Alaska. Here, we...

  20. 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.

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

    International Nuclear Information System (INIS)

    Carlos-Pinedo, C.; Rodríguez-Vargas, I.; Martínez-Orozco, J. C.

    2014-01-01

    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 −2 is affected

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

    International Nuclear Information System (INIS)

    Karimi, M.J.; Rezaei, G.; Nazari, M.

    2014-01-01

    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

  3. The effect of hydrostatic pressure on staurosporine-induced neural differentiation in mouse bone marrow‑derived mesenchymal stem cells.

    Science.gov (United States)

    Javanmard, F; Azadbakht, M; Pourmoradi, M

    2016-01-01

    In this study, the role of hydrostatic pressure on staurosporine-induced neural differentiation in mouse bone marrow mesenchymal stem cells were investigated. The cells were cultured in treatment medium containing 100 nM of staurosporine for 4 hours; then the cells were affected by hydrostatic pressure (0, 25,50, 100 mmHg). The percentage of cell viability by trypan blue staining and the percentage of cell death by Hoechst/PI differential staining were assessed. We obtained the total neurite length. Expression of β-tubulin III and GFAP (Glial fibrillary acidic protein) proteins were also analyzed by immunocytochemistry. The percentage of cell viability in treatments decreased relative to the increase in hydrostatic pressure and time (p Keywords: bone marrow mesenchymal stem cell, hydrostatic pressure, immunocytochemistry, neural differentiation, neurite length, cell differentiation.

  4. TOOL ASSEMBLY WITH BI-DIRECTIONAL BEARING

    Science.gov (United States)

    Longhurst, G.E.

    1961-07-11

    A two-direction motion bearing which is incorporated in a refueling nuclear fuel element trsnsfer tool assembly is described. A plurality of bi- directional bearing assembliesare fixed equi-distantly about the circumference of the transfer tool assembly to provide the tool assembly with a bearing surface- for both axial and rotational motion. Each bi-directional bearing assembly contains a plurality of circumferentially bulged rollers mounted in a unique arrangement which will provide a bearing surface for rotational movement of the tool assembly within a bore. The bi-direc tional bearing assembly itself is capable of rational motion and thus provides for longitudinal movement of the tool assembly.

  5. Estimating Wear Of Installed Ball Bearings

    Science.gov (United States)

    Keba, John E.; Mcvey, Scott E.

    1993-01-01

    Simple inspection and measurement technique makes possible to estimate wear of balls in ball bearing, without removing bearing from shaft on which installed. To perform measurement, one observes bearing cage while turning shaft by hand to obtain integral number of cage rotations and to measure, to nearest 2 degrees, number of shaft rotations producing cage rotations. Ratio between numbers of cages and shaft rotations depends only on internal geometry of bearing and applied load. Changes in turns ratio reflect changes in internal geometry of bearing provided measurements made with similar bearing loads. By assuming all wear occurs on balls, one computes effective value for this wear from change in turns ratio.

  6. EFFECT OF CLEARANCE THE BALL BEARINGS ON INCORRECT WORK OF THREE-SUPORT BEARING SHAFT

    Directory of Open Access Journals (Sweden)

    Jarosław KACZOR

    2014-06-01

    Full Text Available Durability deep groove ball bearings depends on factors (called attributes design, technological and operational. Among the design features one of the most important is play in the bearings. Polish Norm shows five groups of looseness in the bearings, in which the play range from 0 to 105 microns. Manufacturers of rolling bearings they only play group, which has a bearing data, without giving the exact value of the slack. Aim of this study is to determine how it affects the play in the bearings to work three-bearing shafts, including elasticity and resilience three-bearing shafts.

  7. The effect of hydrostatic pressure on conductivity behaviour of needle crystals of iodine and oxygen doped niobium-sulphur compounds

    International Nuclear Information System (INIS)

    Balla, D.D.; Bondarenko, A.V.; Obolenskij, M.A.; Beletskij, V.I.; Chashka, Kh.B.

    1985-01-01

    The effect of the hydrostatic pressures up to 11 kbar on conductivity behaviour of the needle crystal of iodine and oxygen doped niobium-sulphur compounds were studied in the temperature range 4.2-300 K. It is shown that in the temperature range 110-300 K conductivity is thermal activated (P=1 bar). Below 110 K the Mott characteristic is observed. Under hydrostatic pressure the deviations from Mott characteristic occurs. The analysis of data suggested that crystals are doped semiconductors

  8. Two-dimensional properties of n-inversion layers in InSb grain boundaries under high hydrostatic pressure

    International Nuclear Information System (INIS)

    Kraak, W.; Herrmann, R.; Nachtwei, G.

    1985-01-01

    Magnetotransport properties of n-inversion layers in grain boundaries of p-InSb bicrystals are investigated under high hydrostatic pressure up to 10 3 MPa. A rapid decrease of the carrier concentration in the inversion layer is observed when hydrostatic pressure is applied. A simple model taking into account the pressure dependence of the energy band structure of pure InSb is proposed to describe this behaviour. (author)

  9. Hydrostatic pressing effect on some properties of Al2O3 and Sc2O3 base ceramics

    International Nuclear Information System (INIS)

    Artemova, K.K.; Rudenko, L.A.; Maslova, G.Ya.; Levkovich, N.A.; Orlova, L.A.

    1981-01-01

    Found is the effect of hydrostatic pressing pressure on some physico-mechanical properties of the ceramic on the Al 2 O 3 and Se 2 O 3 base. Mathematical models, describing dependences of the strength of materials made of Al 2 O 3 and Sc 2 O 3 on sintering conditions and on hydrostatic pressing pressure, are plotted. Production regimes on the Al 2 O 3 and Sc 2 O 3 base ceramics with improved properties are optimized [ru

  10. Journal and Wave Bearing Impedance Calculation Software

    Science.gov (United States)

    Hanford, Amanda; Campbell, Robert

    2012-01-01

    The wave bearing software suite is a MALTA application that computes bearing properties for user-specified wave bearing conditions, as well as plain journal bearings. Wave bearings are fluid film journal bearings with multi-lobed wave patterns around the circumference of the bearing surface. In this software suite, the dynamic coefficients are outputted in a way for easy implementation in a finite element model used in rotor dynamics analysis. The software has a graphical user interface (GUI) for inputting bearing geometry parameters, and uses MATLAB s structure interface for ease of interpreting data. This innovation was developed to provide the stiffness and damping components of wave bearing impedances. The computational method for computing bearing coefficients was originally designed for plain journal bearings and tilting pad bearings. Modifications to include a wave bearing profile consisted of changing the film thickness profile given by an equation, and writing an algorithm to locate the integration limits for each fluid region. Careful consideration was needed to implement the correct integration limits while computing the dynamic coefficients, depending on the form of the input/output variables specified in the algorithm.

  11. 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.

  12. Inactivation of B. Pumilus spores by combination hydrostatic pressure-radiation treatment of parenteral solutions

    International Nuclear Information System (INIS)

    Wills, P.A.

    1975-01-01

    Bacterial spores are inactivated by moderate hydrostatic pressures. The radiation dose required to sterilize radiation sensitive pharmaceuticals can be considerably reduced using a combination hydrostatic pressure-radiation treatment. This paper describes a combination pressure-radiation sterilization process using Bacillus pumilus spores suspended in water, 0.9% saline, and 5% dextrose solutions. The optimum temperatures for spore inactivation at 35 MPa and the degree of inactivation at 35, 70 and 105 MPa applied for times up to 100 min have been determined. Inactivation was greatest in saline and least in dextrose. Spores in dextrose were only slightly less radiation resistant than in saline or water. It was calculated that the radiation dose required for sterilization could be halved with appropriate compression treatment. Examples of combinations of pressure-radiation suitable for sterilization are given. One combination is compression at 105 MPa for 18 min for a dose of 1.25 Mrad. (author)

  13. 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.

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

    KAUST Repository

    Michoud, Gregoire; Jebbar, Mohamed

    2016-01-01

    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.

  15. 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.

  16. An FBG Optical Approach to Thermal Expansion Measurements under Hydrostatic Pressure.

    Science.gov (United States)

    Rosa, Priscila F S; Thomas, Sean M; Balakirev, Fedor F; Betts, Jon; Seo, Soonbeom; Bauer, Eric D; Thompson, Joe D; Jaime, Marcelo

    2017-11-04

    We report on an optical technique for measuring thermal expansion and magnetostriction at cryogenic temperatures and under applied hydrostatic pressures of 2.0 GPa. Optical fiber Bragg gratings inside a clamp-type pressure chamber are used to measure the strain in a millimeter-sized sample of CeRhIn₅. We describe the simultaneous measurement of two Bragg gratings in a single optical fiber using an optical sensing instrument capable of resolving changes in length [dL/L = (L- L₀)/L₀] on the order of 10 -7 . Our results demonstrate the possibility of performing high-resolution thermal expansion measurements under hydrostatic pressure, a capability previously hindered by the small working volumes typical of pressure cells.

  17. Linear Hyperfine Tuning of Donor Spins in Silicon Using Hydrostatic Strain

    Science.gov (United States)

    Mansir, J.; Conti, P.; Zeng, Z.; Pla, J. J.; Bertet, P.; Swift, M. W.; Van de Walle, C. G.; Thewalt, M. L. W.; Sklenard, B.; Niquet, Y. M.; Morton, J. J. L.

    2018-04-01

    We experimentally study the coupling of group V donor spins in silicon to mechanical strain, and measure strain-induced frequency shifts that are linear in strain, in contrast to the quadratic dependence predicted by the valley repopulation model (VRM), and therefore orders of magnitude greater than that predicted by the VRM for small strains |ɛ |hydrostatic component of strain and achieve semiquantitative agreement with the experimental values. Our results provide a framework for making quantitative predictions of donor spins in silicon nanostructures, such as those being used to develop silicon-based quantum processors and memories. The strong spin-strain coupling we measure (up to 150 GHz per strain, for Bi donors in Si) offers a method for donor spin tuning—shifting Bi donor electron spins by over a linewidth with a hydrostatic strain of order 10-6—as well as opportunities for coupling to mechanical resonators.

  18. Diamond to β-Sn phase transition of silicon under hydrostatic and nonhydrostatic compressions

    International Nuclear Information System (INIS)

    Durandurdu, Murat

    2008-01-01

    We have carried out constant pressure ab initio simulations to study the pressure-induced phase transition of silicon. The diamond to β-Sn phase change under hydrostatic pressure is successfully observed in the simulation. The transformation is based on a fourfold coordinated tetragonal intermediate state having the space group I4 1 /amd. The energy barrier for the transformation is calculated to be about 0.35 eV/atom. Additionally, we investigate the influence of nonhydrostatic compressions on the phase transition of silicon and find that up to 20% stress deviations, silicon converts to a β-Sn structure with a reduced transition pressure. The triaxial compressions cause more reduction in the transition pressure than the uniaxial compressions. The transformation mechanism is practically identical under both hydrostatic and nonhydrostatic conditions

  19. Hydrostatic models of gas in clusters in an unsteady state in the irregular field

    International Nuclear Information System (INIS)

    Sidorov, K.A.

    1985-01-01

    A study is made of the hydrostatic distribution of gas in a system in a steady state in the regular field but an unsteady one in the irregular field. Such a system has a velocity distribution with mean square of the radial velocity greater than the mean square of the transversal. Clusters of galaxies probably have such a structure. It is found that the connection between the densities of the gas and the galaxies established by Cavaliere and Fusco-Femiano also holds for isothermal gas in the considered system. Hydrostatic equilibrium of the gas does not hold for clusters with very large asymmetry of the velocity distribution function of the galaxies. The surface brightness of the x-ray emission of the gas is calculated

  20. 'Second' Ehrenfest equation for second order phase transition under hydrostatic pressure

    Science.gov (United States)

    Moin, Ph. B.

    2018-02-01

    It is shown that the fundamental conditions for the second-order phase transitions ? and ?, from which the two Ehrenfest equations follow (the 'usual' and the 'second' ones), are realised only at zero hydrostatic pressure (?). At ? the volume jump ΔV at the transition is proportional to the pressure and to the jump of the compressibility ΔζV, whereas the entropy jump ΔS is proportional to the pressure and to the jump of the thermal expansion coefficient ΔαV. This means that at non-zero hydrostatic pressure the phase transition is of the first order and is described by the Clausius-Clapeyron equation. At small pressure this equation coincides with the 'second' Ehrenfest equation ?. At high P, the Clausius-Clapeyron equation describes qualitatively the caused by the crystal compression positive curvature of the ? dependence.

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

    Science.gov (United States)

    Michoud, Grégoire; Jebbar, Mohamed

    2016-01-01

    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. PMID:27250364

  2. Chamber with punches made from polycrystal cubic boron nitrides for Moessbauer study at high hydrostatic pressure

    International Nuclear Information System (INIS)

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

    1978-01-01

    The design of a high hydrostatic pressure chamber with polycrystallic boron nitride dies weakly absorbing gamma radiation with energies of more than 14 keV is described. The use of this material permits to investigate single- and polycrystal bodies using the Moessbauer effect when the geometry of the experiment remains unchanged and the hydrostatic pressure is up to 70 kbar. The basic units of the chamber are a teflon capsule placed in a container made of a pressed boron and epoxide resin mixture, electric inputs and a die of polycrystal cubic boron nitride. The pressure is transferred to the sample tested through a liquid (petrol or the 4 to 1 mixture of methanole and ethanole) which does not become solid at a pressure below 37 kbar. Basic dimensions of the chamber are given and the dependence of the pressure in the capsule on the force applied to the chamber is also presented

  3. Effects of hydrostatic pressure and supercritical carbon dioxide on the viability of Botryococcus braunii algae cells.

    Science.gov (United States)

    Yildiz-Ozturk, Ece; Ilhan-Ayisigi, Esra; Togtema, Arnoud; Gouveia, Joao; Yesil-Celiktas, Ozlem

    2018-05-01

    In bio-based industries, Botryococcus braunii is identified as a potential resource for production of hydrocarbons having a wide range of applications in chemical and biopolymer industries. For a sustainable production platform, the algae cultivation should be integrated with downstream processes. Ideally the algae are not harvested, but the product is isolated while cultivation and growth is continued especially if the doubling time is slow. Consequently, hydrocarbons can be extracted while keeping the algae viable. In this study, the effects of pressure on the viability of B. braunii cells were tested hydrostatically and under supercritical CO 2 conditions. Viability was determined by light microscopy, methylene blue uptake and by re-cultivation of the algae after treatments to follow the growth. It was concluded that supercritical CO 2 was lethal to the algae, whereas hydrostatic pressure treatments up to 150 bar have not affected cell viability and recultivation was successful. Copyright © 2018 Elsevier Ltd. All rights reserved.

  4. Quantifying Hydrostatic Pressure in Plant Cells by Using Indentation with an Atomic Force Microscope

    Science.gov (United States)

    Beauzamy, Léna; Derr, Julien; Boudaoud, Arezki

    2015-01-01

    Plant cell growth depends on a delicate balance between an inner drive—the hydrostatic pressure known as turgor—and an outer restraint—the polymeric wall that surrounds a cell. The classical technique to measure turgor in a single cell, the pressure probe, is intrusive and cannot be applied to small cells. In order to overcome these limitations, we developed a method that combines quantification of topography, nanoindentation force measurements, and an interpretation using a published mechanical model for the pointlike loading of thin elastic shells. We used atomic force microscopy to estimate the elastic properties of the cell wall and turgor pressure from a single force-depth curve. We applied this method to onion epidermal peels and quantified the response to changes in osmolality of the bathing solution. Overall our approach is accessible and enables a straightforward estimation of the hydrostatic pressure inside a walled cell. PMID:25992723

  5. Stable hydrostatic equilibrium configurations of the galaxy and implications for its halo

    International Nuclear Information System (INIS)

    Bloemen, J.B.G.M.

    1987-01-01

    Using a variety of observations, it is shown that the gaseous, magnetic field, and cosmic-ray components in the local region of the Galaxy may be in a large-scale hydrostatic equilibrium that is stable against Parker-type instabilities. Lower limits for the density of the halo are derived as a function of its scale height. The temperature of the hot medium in the disk and at large distances from the plane is found to be typically about a million K in a stable equilibrium, whereas around z roughly 1-3 kpc the temperature could be only 200,000-300,000 K. The scale height of the sum of cosmic-ray and magnetic field pressures in a stable hydrostatic equilibrium state is found to be only weakly dependent on the scale height of the gaseous halo. 109 references

  6. 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.

  7. Continuous hydrostatic pressure induces differentiation phenomena in chondrocytes mediated by changes in polycystins, SOX9, and RUNX2.

    Science.gov (United States)

    Karamesinis, Konstantinos; Spyropoulou, Anastasia; Dalagiorgou, Georgia; Katsianou, Maria A; Nokhbehsaim, Marjan; Memmert, Svenja; Deschner, James; Vastardis, Heleni; Piperi, Christina

    2017-01-01

    The present study aimed to investigate the long-term effects of hydrostatic pressure on chondrocyte differentiation, as indicated by protein levels of transcription factors SOX9 and RUNX2, on transcriptional activity of SOX9, as determined by pSOX9 levels, and on the expression of polycystin-encoding genes Pkd1 and Pkd2. ATDC5 cells were cultured in insulin-supplemented differentiation medium (ITS) and/or exposed to 14.7 kPa of hydrostatic pressure for 12, 24, 48, and 96 h. Cell extracts were assessed for SOX9, pSOX9, and RUNX2 using western immunoblotting. The Pkd1 and Pkd2 mRNA levels were detected by real-time PCR. Hydrostatic pressure resulted in an early drop in SOX9 and pSOX9 protein levels at 12 h followed by an increase from 24 h onwards. A reverse pattern was followed by RUNX2, which reached peak levels at 24 h of hydrostatic pressure-treated chondrocytes in ITS culture. Pkd1 and Pkd2 mRNA levels increased at 24 h of combined hydrostatic pressure and ITS treatment, with the latter remaining elevated up to 96 h. Our data indicate that long periods of continuous hydrostatic pressure stimulate chondrocyte differentiation through a series of molecular events involving SOX9, RUNX2, and polycystins-1, 2, providing a theoretical background for functional orthopedic mechanotherapies.

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

    OpenAIRE

    Irena Jeličić; Katarina Lisak; Rajka Božanić

    2012-01-01

    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. ...

  9. Study of the influence of high hydrostatic pressure on wine chemical and sensorial characteristics

    OpenAIRE

    Santos, Mickael da Costa

    2015-01-01

    During the last years, the use of high hydrostatic pressure (HHP) as a non-thermal technology for preservation or aging of wine has increased substantially in the academic community. However, HHP treated wine has been only analysed after the pressure treatment, with no knowledge available on the effects of HHP during subsequent storage. The results presented in this thesis showed that HHP treatments influence the chemical and sensorial properties of wine during storage. The application of ...

  10. 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.

  11. A FEM simulation study of the solid state hydrostatic extrusion of PMMA

    Science.gov (United States)

    Costa, André L. M.; Riffel, Douglas B.; Misiolek, Wojciech Z.; Valberg, Henry S.

    2018-05-01

    Solid state hydrostatic extrusion (SSHE) of polymers below glass transition temperature is used to obtain highly oriented structures. Experimental studies on the SSHE of polymethyl-methacrylate (PMMA) have been made since early eighties but there is no information on internal temperature, stress and strain distribution. In this work we have made 3D FEM simulations of SSHE of PMMA by using the commercial DEFORM package with experimental flow curves and thermal properties from literature. The initial temperature of tooling and workpiece was 90°C, ram speeds were 1.0 and 10.0 mm/min with extrusion ratio R = 3.0. For a comparative analysis, SSHE simulation of the AA7108 aluminum alloy at 400°C was also performed. These ranges of parameters were chosen in order to encompass the parameters found in previously mentioned experiments. The best correlation with experimental hydrostatic pressure was verified for a shear friction coefficient at the material-conical die interface m = 0.50. Force-displacement curve for PMMA presented a constitutive and thermal softening in contrast to a constant force curve for aluminum. The internal temperature in the deformation zone increased in a characteristic "owl's face" profile in contrast to quasi-constant profile of aluminum alloy. In both PMMA and aluminum the stress is hydrostatic inside the container, but the stress profiles are significantly different inside the deformation zone. As expected, the strain and strain-rate profiles are practically the same for the two materials, but the temperature profile has promoted slightly differences in material flow. The velocity gradient from center to surface is higher in PMMA than aluminum. It's supposed that during hydrostatic extrusion solid PMMA has a characteristic thermally-inducted mechanical behavior.

  12. Chemical Abundances of Hydrostatic and Explosive Alpha-elements in Sagittarius Stream Stars

    Science.gov (United States)

    Carlin, Jeffrey L.; Sheffield, Allyson A.; Cunha, Katia; Smith, Verne V.

    2018-05-01

    We analyze chemical abundances of stars in the Sagittarius (Sgr) tidal stream using high-resolution Gemini+GRACES spectra of 42 members of the highest surface-brightness portions of both the trailing and leading arms. Targets were chosen using a 2MASS+WISE color–color selection, combined with the Large Sky Area Multi-Object Fibre Spectroscopic Telescope (LAMOST) radial velocities. In this Letter, we analyze [Fe/H] and α-elements produced by both hydrostatic (O, Mg) and explosive (Si, Ca, Ti) nucleosynthetic processes. The average [Fe/H] for our Sgr stream stars is lower than that for stars in the Sgr core, and stars in the trailing and leading arms show systematic differences in [Fe/H]. Both hydrostatic and explosive elements are depleted relative to Milky Way (MW) disk and halo stars, with a larger gap between the MW trend and Sgr stars for the hydrostatic elements. Chemical abundances of Sgr stream stars show similar patterns to those measured in the core of the Sgr dSph. We explore the ratio of hydrostatic to explosive α-elements [α h/ex] (which we refer to as the “HEx ratio”). Our observed HEx ratio trends for Sgr debris are deficient relative to MW stars. Via simple chemical evolution modeling, we show that these HEx ratio patterns are consistent with a Sgr IMF that lacks the most massive stars. This study provides a link between the chemical properties in the intact Sgr core and the significant portion of the Sgr system’s luminosity that is estimated to currently reside in the streams.

  13. DETECTION OF A BIPOLAR MOLECULAR OUTFLOW DRIVEN BY A CANDIDATE FIRST HYDROSTATIC CORE

    International Nuclear Information System (INIS)

    Dunham, Michael M.; Chen Xuepeng; Arce, Héctor G.; Bourke, Tyler L.; Schnee, Scott; Enoch, Melissa L.

    2011-01-01

    We present new 230 GHz Submillimeter Array observations of the candidate first hydrostatic core Per-Bolo 58. We report the detection of a 1.3 mm continuum source and a bipolar molecular outflow, both centered on the position of the candidate first hydrostatic core. The continuum detection has a total flux density of 26.6 ± 4.0 mJy, from which we calculate a total (gas and dust) mass of 0.11 ± 0.05 M ☉ and a mean number density of 2.0 ± 1.6 × 10 7 cm –3 . There is some evidence for the existence of an unresolved component in the continuum detection, but longer-baseline observations are required in order to confirm the presence of this component and determine whether its origin lies in a circumstellar disk or in the dense inner envelope. The bipolar molecular outflow is observed along a nearly due east-west axis. The outflow is slow (characteristic velocity of 2.9 km s –1 ), shows a jet-like morphology (opening semi-angles ∼8° for both lobes), and extends to the edges of the primary beam. We calculate the kinematic and dynamic properties of the outflow in the standard manner and compare them to several other protostars and candidate first hydrostatic cores with similarly low luminosities. We discuss the evidence both in support of and against the possibility that Per-Bolo 58 is a first hydrostatic core, and we outline future work needed to further evaluate the evolutionary status of this object.

  14. Effect of hydrostatic pressure on the tensile properties of alpha uranium

    International Nuclear Information System (INIS)

    Chandler, E.F.

    1984-09-01

    This report examines the effect of a superimposed hydrostatic pressure on the tensile properties of four grades of rolled unalloyed alpha uranium. The materials varied in carbon content and heat treatment. The principal effect of increasing pressure is an increase in the ductility of the materials. By not heat treating the uranium after the rolling process, the interaction of carbon content on mechanical properties is almost nullified. (author)

  15. The effect of hydrostatic pressure on the anomalous sign reversal of the Hall coefficient in tellurium

    International Nuclear Information System (INIS)

    Balynas, V.; Dobrovolskis, Z.; Krotkus, A.; Hoerstel, W.

    1981-01-01

    In order to obtain information about the pressure behaviour of the higher lying second conduction band the dependences of the Hall coefficient of single crystalline tellurium on temperature (300 to 500 K) have been measured at atmospheric pressure and hydrostatic pressures of 500 and 800 MPa. The separation between the two conduction bands in Te decreases with increasing pressure. The anomalous sign reversal of the Hall coefficient can be well explained by a double-conduction band model

  16. Effect of Coronary Anatomy and Hydrostatic Pressure on Intracoronary Indices of Stenosis Severity.

    Science.gov (United States)

    Härle, Tobias; Luz, Mareike; Meyer, Sven; Kronberg, Kay; Nickau, Britta; Escaned, Javier; Davies, Justin; Elsässer, Albrecht

    2017-04-24

    The authors sought to analyze height differences within the coronary artery tree in patients in a supine position and to quantify the impact of hydrostatic pressure on intracoronary pressure measurements in vitro. Although pressure equalization of the pressure sensor and the systemic pressure at the catheter tip is mandatory in intracoronary pressure measurements, subsequent measurements may be influenced by hydrostatic pressure related to the coronary anatomy in the supine position. Outlining and quantifying this phenomenon is important to interpret routine and pullback pressure measurements within the coronary tree. Coronary anatomy was analyzed in computed tomography angiographies of 70 patients to calculate height differences between the catheter tip and different coronary segments in the supine position. Using a dynamic pressure simulator, the effect of the expected hydrostatic pressure resulting from such height differences on indices stenosis severity was assessed. In all patients, the left anterior and right posterior descending arteries are the highest points of the coronary tree with a mean height difference of -4.9 ± 1.6 cm and -3.8 ± 1.0 cm; whereas the circumflex artery and right posterolateral branches are the lowest points, with mean height differences of 3.9 ± 0.9 cm and 2.6 ± 1.6 cm compared with the according ostium. In vitro measurements demonstrated a correlation of the absolute pressure differences with height differences (r = 0.993; p pressure level. Hydrostatic pressure variations resulting from normal coronary anatomy in a supine position influence intracoronary pressure measurements and may affect their interpretation during stenosis severity assessment. Copyright © 2017 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.

  17. The Effect of Size and Species on Lens Intracellular Hydrostatic Pressure

    Science.gov (United States)

    Gao, Junyuan; Sun, Xiurong; Moore, Leon C.; Brink, Peter R.; White, Thomas W.; Mathias, Richard T.

    2013-01-01

    Purpose. Previous experiments showed that mouse lenses have an intracellular hydrostatic pressure that varied from 335 mm Hg in central fibers to 0 mm Hg in surface cells. Model calculations predicted that in larger lenses, all else equal, pressure should increase as the lens radius squared. To test this prediction, lenses of different radii from different species were studied. Methods. All studies were done in intact lenses. Intracellular hydrostatic pressures were measured with a microelectrode-manometer–based system. Membrane conductances were measured by frequency domain impedance analysis. Intracellular Na+ concentrations were measured by injecting the Na+-sensitive dye sodium-binding benzofuran isophthalate. Results. Intracellular hydrostatic pressures were measured in lenses from mice, rats, rabbits, and dogs with radii (cm) 0.11, 0.22, 0.49, and 0.57, respectively. In each species, pressure varied from 335 ± 6 mm Hg in central fiber cells to 0 mm Hg in surface cells. Further characterization of transport in lenses from mice and rats showed that the density of fiber cell gap junction channels was approximately the same, intracellular Na+ concentrations varied from 17 mM in central fiber cells to 7 mM in surface cells, and intracellular voltages varied from −45 mV in central fiber cells to −60 mV in surface cells. Fiber cell membrane conductance was a factor of 2.7 times larger in mouse than in rat lenses. Conclusions. Intracellular hydrostatic pressure is an important physiological parameter that is regulated in lenses from these different species. The most likely mechanism of regulation is to reduce the density of open Na+-leak channels in fiber cells of larger lenses. PMID:23211824

  18. In situ observation of syntactic foams under hydrostatic pressure using X-ray tomography

    International Nuclear Information System (INIS)

    Lachambre, J.; Maire, E.; Adrien, J.; Choqueuse, D.

    2013-01-01

    Syntactic foams (hollow glass microspheres embedded in a polymeric matrix) are being used increasingly for the purpose of thermal insulation in ultradeep water. A better understanding of the damage mechanisms of these materials at the microsphere scale under such a hydrostatic loading condition is of prior importance in determining actual material limits, improving phenomenological modelling and developing novel formulations in the future. To achieve this goal, a study based on X-ray microtomography was performed on two syntactic foam materials (polypropylene and polyurethane matrix) and a standard foamed PP. A special set up has been designed in order to allow the X-ray microtomographic observation of the material during hydrostatic pressure loading using ethanol as the pressure fluid. Spatial resolution of (3.5 μm) 3 and in situ non-destructive scanning allowed a unique qualitative and quantitative analysis of the composite microstructure during stepwise isotropic compression by hydrostatic pressure up to 50 MPa. The collapse of weaker microspheres were observed during pressure increase and the damage parameters could be estimated. It is shown that the microspheres which are broken or the porosities which are close to the surface in the foamed PP are filled by a fluid (either the ethanol or the polymeric matrix itself). The hydrostatic pressure decreases the volume of the foam only slightly. In the PU matrix, ethanol diffusion is seen to induce swelling of the matrix, which is an unexpected phenomenon but reveals the high potential of X-ray microtomographic observation to improve diffusion analysis in complex media

  19. Hydrostatic and shear consolidation tests with permeability measurements on Waste Isolation Pilot Plant crushed salt

    International Nuclear Information System (INIS)

    Brodsky, N.S.

    1994-03-01

    Crushed natural rock salt is a primary candidate for use as backfill and barrier material at the Waste Isolation Pilot Plant (WIPP) and therefore Sandia National Laboratories (SNL) has been pursuing a laboratory program designed to quantify its consolidation properties and permeability. Variables that influence consolidation rate that have been examined include stress state and moisture content. The experimental results presented in this report complement existing studies and work in progress conducted by SNL. The experiments described in this report were designed to (1) measure permeabilities of consolidated specimens of crushed salt, (2) determine the influence of brine saturation on consolidation under hydrostatic loads, and 3) measure the effects of small applied shear stresses on consolidation properties. The laboratory effort consisted of 18 individual tests: three permeability tests conducted on specimens that had been consolidated at Sandia, six hydrostatic consolidation and permeability tests conducted on specimens of brine-saturated crushed WIPP salt, and nine shear consolidation and permeability tests performed on crushed WIPP salt specimens containing 3 percent brine by weight. For hydrostatic consolidation tests, pressures ranged from 1.72 MPa to 6.90 MPa. For the shear consolidation tests, confining pressures were between 3.45 MPa and 6.90 MPa and applied axial stress differences were between 0.69 and 4.14 MPa. All tests were run under drained conditions at 25 degrees C

  20. Performance of a hydrostatic sampler for collecting samples at the water-sediment interface in lakes

    Directory of Open Access Journals (Sweden)

    Fernando PEDROZO

    2008-02-01

    Full Text Available The water-sediment interface plays a significant role in the determination of the trophic degree of a waterbody. Numerous redox reactions take place there, resulting in the release of contaminants from the sediments to the water column. The aim of the present work was to develop an equipment for collecting samples from the water-sediment interface. Such equipment was to have a simple design, low construction cost, no depth limitations, and high levels of personal safety and to be reliable in the collection of samples. The performance of the hydrostatic sampler thus developed was tested against samples collected either remotely with a corer or directly with syringes by autonomous divers. The hydrostatic sampler permits access to depths where the costs of the traditional diving methodology are expensive, and where working conditions are dangerous for the diver. The hydrostatic sampler provides an additional means of collecting samples from the water-sediment interface, which together with pore-water samples, facilitates the investigation and understanding of chemical mechanisms in lakes, for instance, those that control the P release from sediment to the water column.

  1. Hydrostatic pressure of the O(N) φ4 theory in the large N limit

    International Nuclear Information System (INIS)

    Jizba, Petr

    2004-01-01

    With nonequilibrium applications in mind we present in this paper (the first in a series of three) a self-contained calculation of the hydrostatic pressure of the O(N) λφ 4 theory at finite temperature. By combining the Keldysh-Schwinger closed-time path formalism with thermal Dyson-Schwinger equations we compute in the large N limit the hydrostatic pressure in a fully resumed form. We also calculate the high-temperature expansion for the pressure (in D=4) using the Mellin transform technique. The result obtained extends the results found by Drummond et al. [Nucl. Phys. B524, 579 (1998)] and Amelino-Camelia and Pi [Phys. Rev. D 47, 2356 (1993)]. The latter are reproduced in the limits m r (0)→0, T→∞, and T→∞, respectively. Important issues of renormalizibility of composite operators at finite temperature are addressed and the improved energy-momentum tensor is constructed. The utility of the hydrostatic pressure in the nonequilibrium quantum systems is discussed

  2. Elasto-optics in double-coated optical fibers induced by axial strain and hydrostatic pressure.

    Science.gov (United States)

    Yang, Yu-Ching; Lee, Haw-Long; Chou, Huann-Ming

    2002-04-01

    Stresses, microbending loss, and refractive-index changes induced simultaneously by axial strain and hydrostatic pressure in double-coated optical fibers are analyzed. The lateral pressure and normal stresses in the optical fiber, primary coating, and secondary coating are derived. Also presented are the microbending loss and refractive-index changes in the glass fiber. The normal stresses are affected by axial strain, hydrostatic pressure, material properties, and thickness of the primary and secondary coatings. It is found that microbending loss decreases with increasing thickness, the Young's modulus, and the Poisson's ratio of the secondary coating but increases with the increasing Young's modulus and Poisson's ratio of the primary coating. Similarly, changes in refractive index in the glass fiber decrease with the increasing Young's modulus and Poisson's ratio of the secondary coating but increase with the increasing Young's modulus and Poisson's ratio of the primary coating. Therefore, to minimize microbending loss induced simultaneously by axial strain and hydrostatic pressure in the glass fiber, the polymeric coatings should be suitably selected. An optimal design procedure is also indicated.

  3. 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)

  4. Ultrasound-guided hydrostatic reduction of intussusception with saline: Safe and effective.

    Science.gov (United States)

    Karadağ, Çetin Ali; Abbasoğlu, Latif; Sever, Nihat; Kalyoncu, Meltem Kaba; Yıldız, Abdullah; Akın, Melih; Candan, Mustafa; Dokucu, Ali İhsan

    2015-09-01

    The study was undertaken to assess the efficacy of ultrasound-guided saline enema in reducing intussusception and to determine the role of age and duration of symptoms on this event. The case records of patients who were treated for intussusception at our institutions over the past 10 years were retrospectively analyzed. A total of 419 patients were treated for intussusception and 375 of them were included into the study. Patients were excluded if they had symptoms and signs of acute abdominal disease and required surgery as an initial treatment. Hydrostatic reduction was successful in 313 of the 375 patients (83.46%). The procedure-related complication rate was nil. There were 29 episodes of recurrences in 23 patients, and recurrence rates did not differ between patients who responded to hydrostatic reduction and those who required surgery. Younger age [median (range); 11 months (3-108 months) vs. 20 months (1-180 months); phydrostatic reduction. Ultrasound-guided hydrostatic reduction is an easy, safe and effective method for the treatment of intussusception in the absence of acute abdominal findings. Copyright © 2015 Elsevier Inc. All rights reserved.

  5. Hydrostatic pressure affects in vitro maturation of oocytes and follicles and increases granulosa cell death.

    Science.gov (United States)

    Rashidi, Zahra; Azadbakht, Mehri; Amini, Ali; Karimi, Isac

    2014-01-01

    This study examines the effects of hydrostatic pressure on in vitro maturation (IVM) of oocytes derived from in vitro grown follicles. 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. The percentage of metaphase II oocytes (MII) increased in hydrostatic pressuretreated follicles compared to controls (phydrostatic pressure-treated follicles compared to controls (pHydrostatic pressure, by inducing apoptosis in cumulus cells, participates in the cumulus oocyte coupled relationship with oocyte maturation.

  6. 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.

  7. Calpain: a molecule to induce AIF-mediated necroptosis in RGC-5 following elevated hydrostatic pressure

    Science.gov (United States)

    2014-01-01

    Background RIP3 (Receptor-interacting protein 3) pathway was mainly described as the molecular mechanism of necroptosis (programmed necrosis). But recently, non-RIP3 pathways were found to mediate necroptosis. We deliberate to investigate the effect of calpain, a molecule to induce necroptosis as reported (Cell Death Differ 19:245–256, 2012), in RGC-5 following elevated hydrostatic pressure. Results First, we identified the existence of necroptosis of RGC-5 after insult by using necrostatin-1 (Nec-1, necroptosis inhibitor) detected by flow cytometry. Immunofluorescence staining and western blot were used to detect the expression of calpain. Western blot analysis was carried out to describe the truncated AIF (tAIF) expression with or without pretreatment of ALLN (calpain activity inhibitor). Following elevated hydrostatic pressure, necroptotic cells pretreated with or without ALLN was stained by Annexin V/PI, The activity of calpain was also examined to confirm the inhibition effect of ALLN. The results showed that after cell injury there was an upregulation of calpain expression. Upon adding ALLN, the calpain activity was inhibited, and tAIF production was reduced upon injury along with the decreased number of necroptosis cells. Conclusion Our study found that calpain may induce necroptosis via tAIF-modulation in RGC-5 following elevated hydrostatic pressure. PMID:24884644

  8. Resonant frequency analysis on an electrostatically actuated microplate under uniform hydrostatic pressure

    International Nuclear Information System (INIS)

    Li Zhikang; Zhao Libo; Ye Zhiying; Zhao Yulong; Jiang Zhuangde; Wang Hongyan

    2013-01-01

    The resonant frequency of a microplate is influenced by various physical parameters such as mass, surface stress, hydrostatic pressure and electrostatic force. In this paper, the effects of both electrostatic force and uniform hydrostatic pressure on the resonant frequency of a clamped circular microplate are investigated. An approximate solution is derived for the fundamental resonance frequency of the mciroplate under both types of loads using an energy equivalent method. It is found that both electrostatic force and uniform hydrostatic pressure decrease the resonant frequency of the microplate under small deflections. Additionally, the linearized expression of this solution shows that the resonant frequency varies linearly with pressure in the low and ultra-low range, and the corresponding pressure sensitivity depends on the voltage applied to the microplate. The analytical results are well validated by the finite element method. This study may be helpful for the design and optimization of electrostatically actuated resonance devices based on microplates, especially electrostatically actuated low- or ultra-low-pressure sensors. (paper)

  9. TESTING STRICT HYDROSTATIC EQUILIBRIUM IN SIMULATED CLUSTERS OF GALAXIES: IMPLICATIONS FOR A1689

    International Nuclear Information System (INIS)

    Molnar, S. M.; Umetsu, K.; Chiu, I.-N.; Chen, P.; Hearn, N.; Broadhurst, T.; Bryan, G.; Shang, C.

    2010-01-01

    Accurate mass determination of clusters of galaxies is crucial if they are to be used as cosmological probes. However, there are some discrepancies between cluster masses determined based on gravitational lensing and X-ray observations assuming strict hydrostatic equilibrium (i.e., the equilibrium gas pressure is provided entirely by thermal pressure). Cosmological simulations suggest that turbulent gas motions remaining from hierarchical structure formation may provide a significant contribution to the equilibrium pressure in clusters. We analyze a sample of massive clusters of galaxies drawn from high-resolution cosmological simulations and find a significant contribution (20%-45%) from non-thermal pressure near the center of relaxed clusters, and, in accord with previous studies, a minimum contribution at about 0.1 R vir , growing to about 30%-45% at the virial radius, R vir . Our results strongly suggest that relaxed clusters should have significant non-thermal support in their core region. As an example, we test the validity of strict hydrostatic equilibrium in the well-studied massive galaxy cluster A1689 using the latest high-resolution gravitational lensing and X-ray observations. We find a contribution of about 40% from non-thermal pressure within the core region of A1689, suggesting an alternate explanation for the mass discrepancy: the strict hydrostatic equilibrium is not valid in this region.

  10. Effects of High Hydrostatic Pressure on Coastal Bacterial Community Abundance and Diversity

    Science.gov (United States)

    Marietou, Angeliki

    2014-01-01

    Hydrostatic pressure is an important parameter influencing the distribution of microbial life in the ocean. In this study, the response of marine bacterial populations from surface waters to pressures representative of those under deep-sea conditions was examined. Southern California coastal seawater collected 5 m below the sea surface was incubated in microcosms, using a range of temperatures (16 to 3°C) and hydrostatic pressure conditions (0.1 to 80 MPa). Cell abundance decreased in response to pressure, while diversity increased. The morphology of the community also changed with pressurization to a predominant morphotype of small cocci. The pressure-induced community changes included an increase in the relative abundance of Alphaproteobacteria, Gammaproteobacteria, Actinobacteria, and Flavobacteria largely at the expense of Epsilonproteobacteria. Culturable high-pressure-surviving bacteria were obtained and found to be phylogenetically similar to isolates from cold and/or deep-sea environments. These results provide novel insights into the response of surface water bacteria to changes in hydrostatic pressure. PMID:25063663

  11. Comparing effects of perfusion and hydrostatic pressure on gene profiles of human chondrocyte.

    Science.gov (United States)

    Zhu, Ge; Mayer-Wagner, Susanne; Schröder, Christian; Woiczinski, Matthias; Blum, Helmut; Lavagi, Ilaria; Krebs, Stefan; Redeker, Julia I; Hölzer, Andreas; Jansson, Volkmar; Betz, Oliver; Müller, Peter E

    2015-09-20

    Hydrostatic pressure and perfusion have been shown to regulate the chondrogenic potential of articular chondrocytes. In order to compare the effects of hydrostatic pressure plus perfusion (HPP) and perfusion (P) we investigated the complete gene expression profiles of human chondrocytes under HPP and P. A simplified bioreactor was constructed to apply loading (0.1 MPa for 2 h) and perfusion (2 ml) through the same piping by pressurizing the medium directly. High-density monolayer cultures of human chondrocytes were exposed to HPP or P for 4 days. Controls (C) were maintained in static cultures. Gene expression was evaluated by sequencing (RNAseq) and quantitative real-time PCR analysis. Both treatments changed gene expression levels of human chondrocytes significantly. Specifically, HPP and P increased COL2A1 expression and decreased COL1A1 and MMP-13 expression. Despite of these similarities, RNAseq revealed a list of cartilage genes including ACAN, ITGA10 and TNC, which were differentially expressed by HPP and P. Of these candidates, adhesion related molecules were found to be upregulated in HPP. Both HPP and P treatment had beneficial effects on chondrocyte differentiation and decreased catabolic enzyme expression. The study provides new insight into how hydrostatic pressure and perfusion enhance cartilage differentiation and inhibit catabolic effects. Copyright © 2015 Elsevier B.V. All rights reserved.

  12. High hydrostatic pressure induces pro-osteoarthritic changes in cartilage precursor cells: A transcriptome analysis.

    Science.gov (United States)

    Montagne, Kevin; Onuma, Yasuko; Ito, Yuzuru; Aiki, Yasuhiko; Furukawa, Katsuko S; Ushida, Takashi

    2017-01-01

    Due to the high water content of cartilage, hydrostatic pressure is likely one of the main physical stimuli sensed by chondrocytes. Whereas, in the physiological range (0 to around 10 MPa), hydrostatic pressure exerts mostly pro-chondrogenic effects in chondrocyte models, excessive pressures have been reported to induce detrimental effects on cartilage, such as increased apoptosis and inflammation, and decreased cartilage marker expression. Though some genes modulated by high pressure have been identified, the effects of high pressure on the global gene expression pattern have still not been investigated. In this study, using microarray technology and real-time PCR validation, we analyzed the transcriptome of ATDC5 chondrocyte progenitors submitted to a continuous pressure of 25 MPa for up to 24 h. Several hundreds of genes were found to be modulated by pressure, including some not previously known to be mechano-sensitive. High pressure markedly increased the expression of stress-related genes, apoptosis-related genes and decreased that of cartilage matrix genes. Furthermore, a large set of genes involved in the progression of osteoarthritis were also induced by high pressure, suggesting that hydrostatic pressure could partly mimic in vitro some of the genetic alterations occurring in osteoarthritis.

  13. Electrical resistivity of CeNiSn under uniaxial and hydrostatic pressures

    Science.gov (United States)

    Echizen, Y.; Umeo, K.; Igaue, T.; Takabatake, T.

    2002-05-01

    We present measurements of the electrical resistivity ρ(T) on high-quality single-crystalline CeNiSn under both hydrostatic pressure up to 1 GPa and uniaxial pressure up to 0.25 GPa. At ambient pressure, ρ(T) along the orthorhombic a-axis (b-axis) shows two maxima at TL = 12 K (14 K) and TH = 74 K (40 K), respectively, which arise from the Kondo scattering of conduction electrons by the crystal-field ground state and excited states. With increasing hydrostatic pressure, both TL and TH increase linearly, and for P≥0.8 GPa, the anisotropy in ρ(T) for I∥a and I∥b almost vanishes as a result of increased hybridization between the 4f electrons and the conduction electrons. Under P∥a, both TL and TH in ρ(I∥b) increase similarly to under hydrostatic pressure. Under P∥c, however, the depression of TL in ρ(I∥a) and ρ(I∥b) suggests that the c-f hybridization in the crystal-field ground state is weakened in the a-b plane of CeNiSn.

  14. Modelling and Simulation of a Hydrostatic Steering System for Agricultural Tractors

    Directory of Open Access Journals (Sweden)

    Barbara Zardin

    2018-01-01

    Full Text Available The steering system of a vehicle impacts on the vehicle performance, safety and on the driver’s comfort. Moreover, in off-road vehicles using hydrostatic steering systems, the energy dissipation also becomes a critical issue. These aspects push and motivate innovation, research and analysis in the field of agricultural tractors. This paper proposes the modelling and analysis of a hydrostatic steering system for an agricultural tractor to calculate the performance of the system and determine the influence of its main design parameters. The focus here is on the driver’s steering feel, which can improve the driver’s behavior reducing unnecessary steering corrections during the working conditions. The hydrostatic steering system is quite complex and involves a hydraulic circuit and a mechanical mechanism to transmit the steering to the vehicle tires. The detailed lumped parameters model here proposed allows to simulate the dynamic behavior of the steering system and to both enhance the understanding of the system and to improve the design through parameters sensitivity analysis.

  15. Stable isotopes to detect food-conditioned bears and to evaluate human-bear management

    Science.gov (United States)

    Hopkins, John B.; Koch, Paul L.; Schwartz, Charles C.; Ferguson, Jake M.; Greenleaf, Schuyler S.; Kalinowski, Steven T.

    2012-01-01

    We used genetic and stable isotope analysis of hair from free-ranging black bears (Ursus americanus) in Yosemite National Park, California, USA to: 1) identify bears that consume human food, 2) estimate the diets of these bears, and 3) evaluate the Yosemite human–bear management program. Specifically, we analyzed the isotopic composition of hair from bears known a priori to be food-conditioned or non-food-conditioned and used these data to predict whether bears with an unknown management status were food-conditioned (FC) or non-food-conditioned (NFC). We used a stable isotope mixing model to estimate the proportional contribution of natural foods (plants and animals) versus human food in the diets of FC bears. We then used results from both analyses to evaluate proactive (population-level) and reactive (individual-level) human–bear management, and discussed new metrics to evaluate the overall human–bear management program in Yosemite. Our results indicated that 19 out of 145 (13%) unknown bears sampled from 2005 to 2007 were food-conditioned. The proportion of human food in the diets of known FC bears likely declined from 2001–2003 to 2005–2007, suggesting proactive management was successful in reducing the amount of human food available to bears. In contrast, reactive management was not successful in changing the management status of known FC bears to NFC bears, or in reducing the contribution of human food to the diets of FC bears. Nine known FC bears were recaptured on 14 occasions from 2001 to 2007; all bears were classified as FC during subsequent recaptures, and human–bear management did not reduce the amount of human food in the diets of FC bears. Based on our results, we suggest Yosemite continue implementing proactive human–bear management, reevaluate reactive management, and consider removing problem bears (those involved in repeated bear incidents) from the population.

  16. Technology development for indigenous water lubricated bearings

    International Nuclear Information System (INIS)

    Limaye, P.K.; Soni, N.L.; Agrawal, R.G.

    2010-01-01

    Water Lubricated Bearings (WLB) are used in various mechanisms of fuel handling systems of PHWRs and AHWR. Availability and random failures of these bearings was a major factor in refuelling operations. Indigenous development of these bearings was taken up and 7 types of antifriction bearings in various sizes (totaling 37 variants) for PHWR, AHWR and Dhruva applications were successfully developed. This paper deals with various aspects of WLB development. (author)

  17. Research In Diagnosing Bearing Defects From Vibrations

    Science.gov (United States)

    Zoladz, T.; Earhart, E.; Fiorucci, T.

    1995-01-01

    Report describes research in bearing-defect signature analysis - use of vibration-signal analysis to diagnose defects in roller and ball bearings. Experiments performed on bearings in good condition and other bearings in which various parts scratched to provide known defects correlated with vibration signals. Experiments performed on highly instrumented motor-driven rotor assembly at speeds up to 10,050 r/min, using accelerometers, velocity probes, and proximity sensors mounted at various locations on assembly to measure vibrations.

  18. Cool Polar Bears: Dabbing on the Texture

    Science.gov (United States)

    O'Connell, Jean

    2011-01-01

    In this article, the author describes how her second-graders created their cool polar bears. The students used the elements of shape and texture to create the bears. They used Monet's technique of dabbing paint so as to give the bear some texture on his fur.

  19. 49 CFR 229.64 - Plain bearings.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Plain bearings. 229.64 Section 229.64 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION....64 Plain bearings. A plain bearing box shall contain visible free oil and may not be cracked to the...

  20. Bearing-Mounting Concept Accommodates Thermal Expansion

    Science.gov (United States)

    Nespodzany, Robert; Davis, Toren S.

    1995-01-01

    Pins or splines allow radial expansion without slippage. Design concept for mounting rotary bearing accommodates differential thermal expansion between bearing and any structure(s) to which bearing connected. Prevents buildup of thermal stresses by allowing thermal expansion to occur freely but accommodating expansion in such way not to introduce looseness. Pin-in-slot configuration also maintains concentricity.

  1. Bears and pipeline construction in Alaska

    Energy Technology Data Exchange (ETDEWEB)

    Follmann, E.H.; Hechtel, J.L. (Univ. of Alaska Fairbanks, AK (USA))

    1990-06-01

    Serious problems were encountered with bears during construction of the 1274-km trans-Alaska oil pipeline between Prudhoe Bay and Valdez. This multi-billion-dollar project traversed both black bear (Ursus americanus Pallas) and grizzly bear (U. arctos L.) habitat throughtout its entire length. Plans for dealing with anticipated problems with bears were often inadequate. Most (71%) problems occurred north of the Yukon River in a previously roadless wilderness where inadequate refuse disposal and widespread animal feeding created dangerous situations. Of the 192 officially reported bear problems associated with the Trans-Alaska Pipeline System (TAPS) (1971-1979), about 65% involved the presence of bears in camps or dumps, 13% the feeding of bears on garbage or handouts, 10% property damage or economic loss, 7% bears under and in buildings, and only 5% charges by bears. Remarkably, no bear-related injuries were reported, suggesting that bears became accustomed to people and did not regard them as a threat. Following construction of the TAPS there have been proposals for pipelines to transport natural gas from Prudhoe Bay to southern and Pacific-rim markets. Based on past experience, some animal control measures were developed during the planning phase for the authorized gas pipeline route in Alaska. Fences installed around 100-person survey camps were found to be effective in deterring bears in two traditionally troublesome areas. 16 refs., 7 figs., 1 tab.

  2. Fractal analysis of polar bear hairs

    Directory of Open Access Journals (Sweden)

    Wang Qing-Li

    2015-01-01

    Full Text Available Hairs of a polar bear (Ursus maritimus are of superior properties such as the excellent thermal protection. Why do polar bears can resist such cold environment? The paper concludes that its fractal porosity plays an important role, and its fractal dimensions are very close to the golden mean, 1.618, revealing the possible optimal structure of polar bear hair.

  3. 36 CFR 13.1236 - Bear orientation.

    Science.gov (United States)

    2010-07-01

    ... 36 Parks, Forests, and Public Property 1 2010-07-01 2010-07-01 false Bear orientation. 13.1236 Section 13.1236 Parks, Forests, and Public Property NATIONAL PARK SERVICE, DEPARTMENT OF THE INTERIOR... Developed Area § 13.1236 Bear orientation. All persons visiting the BCDA must receive an NPS-approved Bear...

  4. 14 CFR 29.623 - Bearing factors.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Bearing factors. 29.623 Section 29.623... STANDARDS: TRANSPORT CATEGORY ROTORCRAFT Design and Construction General § 29.623 Bearing factors. (a... subject to pounding or vibration, must have a bearing factor large enough to provide for the effects of...

  5. 14 CFR 27.623 - Bearing factors.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Bearing factors. 27.623 Section 27.623... STANDARDS: NORMAL CATEGORY ROTORCRAFT Design and Construction General § 27.623 Bearing factors. (a) Except... subject to pounding or vibration, must have a bearing factor large enough to provide for the effects of...

  6. 14 CFR 25.623 - Bearing factors.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Bearing factors. 25.623 Section 25.623... STANDARDS: TRANSPORT CATEGORY AIRPLANES Design and Construction General § 25.623 Bearing factors. (a) Except... subject to pounding or vibration, must have a bearing factor large enough to provide for the effects of...

  7. 14 CFR 23.623 - Bearing factors.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Bearing factors. 23.623 Section 23.623... Bearing factors. (a) Each part that has clearance (free fit), and that is subject to pounding or vibration, must have a bearing factor large enough to provide for the effects of normal relative motion. (b) For...

  8. The BEAR Beamline at Elettra

    International Nuclear Information System (INIS)

    Nannarone, S.; Pasquali, L.; Selvaggi, G.; Borgatti, F.; DeLuisa, A.; Doyle, B.P.; Gazzadi, G.C.; Giglia, A.; Finetti, P.; Pedio, M.; Mahne, N.; Naletto, G.; Pelizzo, M.G.; Tondello, G.

    2004-01-01

    The BEAR (Bending Magnet for Emission Absorption and Reflectivity) beamline is installed at the right exit of the 8.1 bending magnet at ELETTRA. The beamline - in operation since January 2003 - delivers linear and circularly polarized radiation in the 5 - 1600 eV energy range. The experimental station is composed of a UHV chamber for reflectivity, absorption, fluorescence and angle resolved photoemission measurements and a UHV chamber for in-situ sample preparation

  9. Combined effects of hydrostatic pressure and electric field on the donor binding energy and polarizability in laterally coupled double InAs/GaAs quantum-well wires

    International Nuclear Information System (INIS)

    Tangarife, E.; Duque, C.A.

    2010-01-01

    This work is concerned with the theoretical study of the combined effects of applied electric field and hydrostatic pressure on the binding energy and impurity polarizability of a donor impurity in laterally coupled double InAs/GaAs quantum-well wires. calculations have been made in the effective mass and parabolic band approximations and using a variational method. The results are reported for different configurations of wire and barriers widths, impurity position, and electric field and hydrostatic pressure strengths. Our results show that for symmetrical structures the binding energy is an even function of the impurity position along the growth direction of the structure. Also, we found that for hydrostatic pressure strength up to 38 kbar, the binding energy increases linearly with hydrostatic pressure, while for larger values of hydrostatic pressure the binding energy has a nonlinear behavior. Finally, we found that the hydrostatic pressure can increase the coupling between the two parallel quantum well wires.

  10. BEAR

    DEFF Research Database (Denmark)

    Houmøller, Sabina Storbjerg; Wolff, Anne; Hougaard, Dan Dupont

    2017-01-01

    profiling and fitting strategies. Data from 2000 patients are collected from the departments of Audiology in Odense and Aalborg University Hospital. Some of the registered variables include gender, age, and health related questions, noise exposure and whether they are suffering from tinnitus. The database...... subgroups of HA users, including experienced versus new HA users will be made. Previous noise exposure and the relation to the occurrence of tinnitus will be investigated as well....

  11. Scaling laws for radial foil bearings

    Science.gov (United States)

    Honavara Prasad, Srikanth

    The effects of fluid pressurization, structural deformation of the compliant members and heat generation in foil bearings make the design and analysis of foil bearings very complicated. The complex fluid-structural-thermal interactions in foil bearings also make modeling efforts challenging because these phenomena are governed by highly non-linear partial differential equations. Consequently, comparison of various bearing designs require detailed calculation of the flow fields (velocities, pressures), bump deflections (structural compliance) and heat transfer phenomena (viscous dissipation in the fluid, frictional heating, temperature profile etc.,) resulting in extensive computational effort (time/hardware). To obviate rigorous computations and aid in feasibility assessments of foil bearings of various sizes, NASA developed the "rule of thumb" design guidelines for estimation of journal bearing load capacity. The guidelines are based on extensive experimental data. The goal of the current work is the development of scaling laws for radial foil bearings to establish an analytical "rule of thumb" for bearing clearance and bump stiffness. The use of scale invariant Reynolds equation and experimentally observed NASA "rule of thumb" yield scale factors which can be deduced from first principles. Power-law relationships between: a. Bearing clearance and bearing radius, and b. bump stiffness and bearing radius, are obtained. The clearance and bump stiffness values obtained from scaling laws are used as inputs for Orbit simulation to study various cases. As the clearance of the bearing reaches the dimensions of the material surface roughness, asperity contact breaks the fluid film which results in wear. Similarly, as the rotor diameter increases (requiring larger bearing diameters), the load capacity of the fluid film should increase to prevent dry rubbing. This imposes limits on the size of the rotor diameter and consequently bearing diameter. Therefore, this thesis aims

  12. Improvement of journal bearing operation at heavy misalignment using bearing flexibility and compliant liners

    DEFF Research Database (Denmark)

    Thomsen, Kim; Klit, Peder

    2012-01-01

    A flexure journal bearing design is proposed that will improve operational behaviour of a journal bearing at pronounced misalignment. Using a thermoelastohydrodynamic model, it is shown that the proposed flexure journal bearing has vastly increased the hydrodynamic performance compared to the stiff...... bearing when misaligned. The hydrodynamic performance is evaluated on lubricant film thickness, pressure and temperature. Furthermore, the influence of a compliant bearing liner is investigated and it is found that it increases the hydrodynamic performance when applied to a stiff bearing, whereas...... the liner has practically no influence on the flexure journal bearing's performance....

  13. A motor with superconducting magnetic bearings

    International Nuclear Information System (INIS)

    Gladun, A.; Stoye, P.; Verges, P.; Gawalek, W.; Habisreuther, T.; Goernert, P.

    1993-01-01

    Superconducting bearings may be one of the most promising near term applications of HTSC. For use at liquid nitrogen temperature and below, they offer the advantage of lower energy consumption and higher reliability. Different bearing configurations have been proposed. But in order to substitute for conventional bearings a further increase in the critical current density of the superconductor and improved bearing concepts are necessary. For this it is necessary to take into account the peculiarities of the interaction between permanent magnets and bulk superconductors. As a contribution to this programme we present the model of a motor with superconducting magnetic bearings. (orig.)

  14. [Advances in studies on bear bile powder].

    Science.gov (United States)

    Zhou, Chao-fan; Gao, Guo-jian; Liu, Ying

    2015-04-01

    In this paper, a detailed analysis was made on relevant literatures about bear bile powder in terms of chemical component, pharmacological effect and clinical efficacy, indicating bear bile powder's significant pharmacological effects and clinical application in treating various diseases. Due to the complex composition, bear bile powder is relatively toxic. Therefore, efforts shall be made to study bear bile powder's pharmacological effects, clinical application, chemical composition and toxic side-effects, with the aim to provide a scientific basis for widespread reasonable clinical application of bear bile powder.

  15. Valve assembly having remotely replaceable bearings

    International Nuclear Information System (INIS)

    Johnson, E.R.; Tanner, D.E.

    1980-01-01

    A valve assembly having remotely replaceable bearings is disclosed wherein a valve disc is supported within a flow duct for rotation about a pair of axially aligned bearings, one of which is carried by a spindle received within a diametral bore in the valve disc, and the other of which is carried by a bearing support block releasably mounted on the duct circumferentially of an annular collar on the valve disc coaxial with its diametrical bore. The spindle and bearing support block are adapted for remote removal to facilitate servicing or replacement of the valve disc support bearings

  16. Ball Bearing Analysis with the ORBIS Tool

    Science.gov (United States)

    Halpin, Jacob D.

    2016-01-01

    Ball bearing design is critical to the success of aerospace mechanisms. Key bearing performance parameters, such as load capability, stiffness, torque, and life all depend on accurate determination of the internal load distribution. Hence, a good analytical bearing tool that provides both comprehensive capabilities and reliable results becomes a significant asset to the engineer. This paper introduces the ORBIS bearing tool. A discussion of key modeling assumptions and a technical overview is provided. Numerous validation studies and case studies using the ORBIS tool are presented. All results suggest the ORBIS code closely correlates to predictions on bearing internal load distributions, stiffness, deflection and stresses.

  17. Servo Reduces Friction In Flexure Bearing

    Science.gov (United States)

    Clingman, W. Dean

    1991-01-01

    Proposed servocontrol device reduces such resistive torques as stiction, friction, ripple, and cogging in flexure bearing described in LAR-14348, "Flexure Bearing Reduces Startup Friction". Reduces frictional "bump" torque encountered when bearing ball runs into buildup of grease on bearing race. Also used as cable follower to reduce torque caused by cable and hoses when they bend because of motion of bearing. New device includes torquer across ball race. Torquer controlled by servo striving to keep flexure at null, removing torque to outer ring. In effect, device is inner control loop reducing friction, but does not control platforms or any outer-control-loop functions.

  18. Cathodic over-potential and hydrogen partial pressure coupling in hydrogen evolution reaction of marine steel under hydrostatic pressure

    International Nuclear Information System (INIS)

    Xiong, X.L.; Zhou, Q.J.; Li, J.X.; Volinsky, Alex A.; Su, Y.J.

    2017-01-01

    Highlights: •Hydrostatic pressure increases the Volmer and the Heyrovsky reactions rates. •Hydrostatic pressure decreases the Tafel reaction rate. •Hydrogen adsorption conditions change with pressure under −1.2 and −1.3 V SSE . •Under −1.2 and −1.3 V SSE , the Heyrovsky reaction dominates the hydrogen recombination. •Under −1.0 and −1.1 V SSE , the Tafel reaction dominates the hydrogen recombination. -- Abstract: A new electrochemical impedance spectroscopy (EIS) model, which considers both the Tafel recombination and the Heyrovsky reaction under permeable boundary conditions, was developed to characterize the kinetic parameters of the hydrogen evolution reaction (HER) under hydrostatic pressure. The effect of the hydrostatic pressure on the kinetic parameters of the HER and the permeation of A514 steel in alkaline solution were measured using potentiodynamic polarization, the Devanathan cell hydrogen permeation, and EIS. The hydrostatic pressure accelerates the Volmer reaction and inhibits the Tafel recombination, which increases the number of adsorbed hydrogen atoms. On the other hand, the pressure accelerates the Heyrovsky reaction, which decreases the amount of adsorbed hydrogen atoms. At 10 to 40 MPa hydrostatic pressure within the −1.0 to −1.1 V SSE cathodic potential region, the HER is controlled by hydrogen partial pressure, and hydrogen adsorption is the Langmuir type. Within the −1.2 to −1.3 V SSE cathodic potential region, the HER is controlled by the potential, and hydrogen adsorption gradually transfers from the Langmuir type to the Temkin type with increasing hydrostatic pressure.

  19. 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.

  20. Influence of Hydrostatic Pressure on the Corrosion Behavior of Superhydrophobic Surfaces on Bare and Oxidized Aluminum Substrates.

    Science.gov (United States)

    Ou, J F; Fang, X Z; Zhao, W J; Lei, S; Xue, M S; Wang, F J; Li, C Q; Lu, Y L; Li, W

    2018-05-22

    It is generally recognized that superhydrophobic surfaces in water may be used for corrosion resistance due to the entrapped air in the solid/liquid interface and could find potential applications in the protection of ship hull. For a superhydrophobic surface, as its immersion depth into water increases, the resultant hydrostatic pressure is also increased, and the entrapped air can be squeezed out much more easily. It is therefore predicted that high hydrostatic pressure would cause an unexpected decrease in corrosion resistance for the vessels in deep water (e.g., submarines) because of the unstable entrapped air. In this work, in order to clarify the role of hydrostatic pressure in the corrosion behavior of superhydrophobic surfaces, two typical superhydrophobic surfaces (SHSs) were prepared on bare and oxidized aluminum substrates, respectively, and then were immersed into the NaCl aqueous solutions with different depths of ∼0 cm (hydrostatic pressure ∼0 kPa), 10 cm (1 kPa), and 150 cm (15 kPa). It was found out for the SHSs on the oxidized Al, as the hydrostatic pressure increased, the corrosion behavior became severe. However, for the SHSs on the bare Al, their corrosion behavior was complex due to hydrostatic pressure. It was found that the corrosion resistance under 1 kPa was the highest. Further mechanism analysis revealed that this alleviated corrosion behavior under 1 kPa resulted from suppressing the oxygen diffusion through the liquid and reducing the subsequent corrosion rate as compared with 0 kPa, whereas the relatively low hydrostatic pressure (HP) could stabilize the entrapped air and hence enhance the corrosion resistance, compared with 15 kPa. The present study therefore provided a fundamental understanding for the applications of SHSs to prevent the corrosion, especially for various vessels in deep water.

  1. Identification of Bearing Failure Using Signal Vibrations

    Science.gov (United States)

    Yani, Irsyadi; Resti, Yulia; Burlian, Firmansyah

    2018-04-01

    Vibration analysis can be used to identify damage to mechanical systems such as journal bearings. Identification of failure can be done by observing the resulting vibration spectrum by measuring the vibration signal occurring in a mechanical system Bearing is one of the engine elements commonly used in mechanical systems. The main purpose of this research is to monitor the bearing condition and to identify bearing failure on a mechanical system by observing the resulting vibration. Data collection techniques based on recordings of sound caused by the vibration of the mechanical system were used in this study, then created a database system based bearing failure due to vibration signal recording sounds on a mechanical system The next step is to group the bearing damage by type based on the databases obtained. The results show the percentage of success in identifying bearing damage is 98 %.

  2. A prototype construction of bearing heater system

    International Nuclear Information System (INIS)

    Firman Silitonga

    2007-01-01

    A bearing heater system has been successfully constructed using transformer-like method of 1000 VA power, 220 V primary voltage, and 50 Hz electrical frequency. The bearing heater consists of primary coil 230 turns, U type and bar-type iron core with 36 cm 2 , 9 cm 2 ,and 3 cm 2 cross-section, and electrical isolation. The bearing heater is used to enlarge the diameter of the bearing so that it can be easily fixed on an electric motor shaft during replacement because the heating is conducted by treated the bearing as a secondary coil of a transformer. This bearing heater can be used for bearing with 3 and 6 cm of inner diameter and 12 cm of maximum outside diameter. (author)

  3. Noise of oil lubricated journal bearings

    International Nuclear Information System (INIS)

    Rho, Byoung Hoo; Kim, Kyung Woong

    2002-01-01

    The purpose of the paper is to provide a procedure to calculate the noise of oil lubricated journal bearings. To do this, the nonlinear transient analysis of rotor-bearing system including rotor imbalance is performed. Acoustical properties of the bearing are investigated through frequency analysis of the pressure fluctuation of the fluid film calculated from the nonlinear analysis. Furthermore, a transmission theory of plane waves on a boundary of the outer surface of the bearing is used to obtain the sound pressure level of the bearing. Results show that the sound pressure level of the bearing can be increased with the rotational speed of the rotor although the whirl amplitude of the rotor is decreased at high speed. Noise estimating procedures presented in this paper could be an aid in the evaluation and understanding of acoustical properties of oil lubricated journal bearings

  4. Genomic evidence of geographically widespread effect of gene flow from polar bears into brown bears.

    Science.gov (United States)

    Cahill, James A; Stirling, Ian; Kistler, Logan; Salamzade, Rauf; Ersmark, Erik; Fulton, Tara L; Stiller, Mathias; Green, Richard E; Shapiro, Beth

    2015-03-01

    Polar bears are an arctic, marine adapted species that is closely related to brown bears. Genome analyses have shown that polar bears are distinct and genetically homogeneous in comparison to brown bears. However, these analyses have also revealed a remarkable episode of polar bear gene flow into the population of brown bears that colonized the Admiralty, Baranof and Chichagof islands (ABC islands) of Alaska. Here, we present an analysis of data from a large panel of polar bear and brown bear genomes that includes brown bears from the ABC islands, the Alaskan mainland and Europe. Our results provide clear evidence that gene flow between the two species had a geographically wide impact, with polar bear DNA found within the genomes of brown bears living both on the ABC islands and in the Alaskan mainland. Intriguingly, while brown bear genomes contain up to 8.8% polar bear ancestry, polar bear genomes appear to be devoid of brown bear ancestry, suggesting the presence of a barrier to gene flow in that direction. © 2014 The Authors. Molecular Ecology Published by John Wiley & Sons Ltd.

  5. Development and Evaluation of Titanium Spacesuit Bearings

    Science.gov (United States)

    Rhodes, Richard; Battisti, Brian; Ytuarte, Raymond, Jr.; Schultz, Bradley

    2016-01-01

    The Z-2 Prototype Planetary Extravehicular Space Suit Assembly is a continuation of NASA's Z-series of spacesuits, designed with the intent of meeting a wide variety of exploration mission objectives, including human exploration of the Martian surface. Incorporating titanium bearings into the Z-series space suit architecture allows us to reduce mass by an estimated 23 lbs per suit system compared to the previously used stainless steel bearing race designs, without compromising suit functionality. There are two obstacles to overcome when using titanium for a bearing race- 1) titanium is flammable when exposed to the oxygen wetted environment inside the space suit and 2) titanium's poor wear properties are often challenging to overcome in tribology applications. In order to evaluate the ignitability of a titanium space suit bearing, a series of tests were conducted at White Sands Test Facility (WSTF) that introduced the bearings to an extreme test profile, with multiple failures imbedded into the test bearings. The testing showed no signs of ignition in the most extreme test cases; however, substantial wear of the bearing races was observed. In order to design a bearing that can last an entire exploration mission (approx. 3 years), design parameters for maximum contact stress need to be identified. To identify these design parameters, bearing test rigs were developed that allow for the quick evaluation of various bearing ball loads, ball diameters, lubricants, and surface treatments. This test data will allow designers to minimize the titanium bearing mass for a specific material and lubricant combination and design around a cycle life requirement for an exploration mission. This paper reviews the current research and testing that has been performed on titanium bearing races to evaluate the use of such materials in an enriched oxygen environment and to optimize the bearing assembly mass and tribological properties to accommodate for the high bearing cycle life for an

  6. Conditioning of alpha bearing wastes

    International Nuclear Information System (INIS)

    1991-01-01

    Alpha bearing wastes are generated during the reprocessing of spent fuel, mixed oxide fuel fabrication, decommissioning and other activities. The safe and effective management of these wastes is of particular importance owing to the radiotoxicity and long lived characteristics of certain transuranic (TRU) elements. The management of alpha bearing wastes involves a number of stages which include collection, characterization, segregation, treatment, conditioning, transport, storage and disposal. This report describes the currently available matrices and technologies for the conditioning of alpha wastes and relates them to their compatibility with the other stages of the waste management process. The selection of a specific immobilization process is dependent on the waste treatment state and the subsequent handling, transport, storage and disposal requirements. The overall objectives of immobilization are similar for all waste producers and processors, which are to produce: (a) Waste forms with sufficient mechanical, physical and chemical stability to satisfy all stages of handling, transport and storage (referred to as the short term requirements), and (b) Waste forms which will satisfy disposal requirements and inhibit the release of radionuclides to the biosphere (referred to as the long term requirements). Cement and bitumen processes have already been successfully applied to alpha waste conditioning on the industrial scale in many of the IAEA Member States. Cement systems based on BFS and pozzolanic cements have emerged as the principal encapsulation matrices for the full range of alpha bearing wastes. Alternative technologies, such as polymers and ceramics, are being developed for specific waste streams but are unlikely to meet widespread application owing to cost and process complexity. The merits of alpha waste conditioning are improved performance in transport, storage and disposal combined with enhanced public perception of waste management operations. These

  7. RESIDUAL GAS MOTIONS IN THE INTRACLUSTER MEDIUM AND BIAS IN HYDROSTATIC MEASUREMENTS OF MASS PROFILES OF CLUSTERS

    International Nuclear Information System (INIS)

    Lau, Erwin T.; Kravtsov, Andrey V.; Nagai, Daisuke

    2009-01-01

    We present analysis of bulk and random gas motions in the intracluster medium using high-resolution Eulerian cosmological simulations of 16 simulated clusters, including both very relaxed and unrelaxed systems and spanning a virial mass range of 5 x 10 13 - 2 x 10 15 h -1 M-odot. We investigate effects of the residual subsonic gas motions on the hydrostatic estimates of mass profiles and concentrations of galaxy clusters. In agreement with previous studies, we find that the gas motions contribute up to ∼5%-15% of the total pressure support in relaxed clusters with contribution increasing with the cluster-centric radius. The fractional pressure support is higher in unrelaxed systems. This contribution would not be accounted for in hydrostatic estimates of the total mass profile and would lead to systematic underestimate of mass. We demonstrate that total mass can be recovered accurately if pressure due to gas motions measured in simulations is explicitly taken into account in the equation of hydrostatic equilibrium. Given that the underestimate of mass is increasing at larger radii, where gas is less relaxed and contribution of gas motions to pressure is larger, the total density profile derived from hydrostatic analysis is more concentrated than the true profile. This may at least partially explain some high values of concentrations of clusters estimated from hydrostatic analysis of X-ray data.

  8. Theoretical studies of optical gain tuning by hydrostatic pressure in GaInNAs/GaAs quantum wells

    International Nuclear Information System (INIS)

    Gladysiewicz, M.; Wartak, M. S.; Kudrawiec, R.

    2014-01-01

    In order to describe theoretically the tuning of the optical gain by hydrostatic pressure in GaInNAs/GaAs quantum wells (QWs), the optical gain calculations within kp approach were developed and applied for N-containing and N-free QWs. The electronic band structure and the optical gain for GaInNAs/GaAs QW were calculated within the 10-band kp model which takes into account the interaction of electron levels in the QW with the nitrogen resonant level in GaInNAs. It has been shown that this interaction increases with the hydrostatic pressure and as a result the optical gain for GaInNAs/GaAs QW decreases by about 40% and 80% for transverse electric and transverse magnetic modes, respectively, for the hydrostatic pressure change from 0 to 40 kilobars. Such an effect is not observed for N-free QWs where the dispersion of electron and hole energies remains unchanged with the hydrostatic pressure. This is due to the fact that the conduction and valence band potentials in GaInAs/GaAs QW scale linearly with the hydrostatic pressure

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

    International Nuclear Information System (INIS)

    Bouzaïene, L.; Ben Mahrsia, R.; Baira, M.; Sfaxi, L.; Maaref, H.

    2013-01-01

    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: ► Theoretical calculation of the nonlinear optical rectification in a lens shape InAs/GaAs quantum dot was performed. ► Optical rectification susceptibility is quite sensitive to the applied hydrostatic pressure and temperature. ► The oscillator strength is strongly affected by the applied hydrostatic pressure and temperature.

  10. Comparison of Alignment Correction Angles Between Fixed-Bearing and Mobile-Bearing UKA.

    Science.gov (United States)

    Inoue, Atsuo; Arai, Yuji; Nakagawa, Shuji; Inoue, Hiroaki; Yamazoe, Shoichi; Kubo, Toshikazu

    2016-01-01

    Good outcomes have been reported with both fixed-bearing and mobile-bearing unicompartmental knee arthroplasty (UKA). However, overcorrected alignment could induce the progression of arthritis on the non-arthroplasty side. Changes of limb alignment after UKA with both types of bearings (fixed bearing: 24 knees, mobile bearing: 28 knees) were investigated. The mean difference between the preoperative standing femoral-tibial angle (FTA) and postoperative standing FTA was significantly larger in mobile bearing UKA group. In fixed-bearing UKA, there must be some laxity in MCL tension so that a 2-mm tension gauge can be inserted. In mobile-bearing UKA, appropriate MCL tension is needed to prevent bearing dislocation. This difference in MCL tension may have caused the difference in the correction angle between the groups. Copyright © 2016 Elsevier Inc. All rights reserved.

  11. Seismic isolation rubber bearings for nuclear facilities

    International Nuclear Information System (INIS)

    Fujita, Takafumi

    1991-01-01

    This paper describes results of biaxial breaking tests by compression and shear and by tension and shear for seismic isolation rubber bearings with bolted-type connections. The bearings used in the tests were low-damping rubber bearings, high-damping rubber bearings, and lead-rubber bearings. Three modes of failure of the bolted-type bearings were observed in the tests. They are the breaking failure by tension and shear; the breaking failure by compression and shear; and the buckling failure by compression and shear. The first and the second modes of failures are almost independent of the types and the sizes of the bearings. The breaking conditions of those failure modes are described in the axial-stress-shear-strain plane. This expression is useful for the evaluation of safety margins of the bearings. The paper outlines the basic design of the nuclear-grade bearings which were used for large-scale rubber bearing tests in a research project for seismic isolation of FBR plants. It also discusses the protection method against aging and the quality control which are important for implementation. (orig./HP)

  12. Seismic isolation rubber bearings for nuclear facilities

    International Nuclear Information System (INIS)

    Fujita, Takafumi

    1989-01-01

    This paper describes results of biaxial breaking tests by compression and shear and by tension and shear for seismic isolation rubber bearings with bolted-type connections. The bearings used in the tests were low-damping rubber bearings, high-damping rubber bearings, and lead-rubber bearings. Three modes of failure of the bolted-type bearings were observed in the tests. They are the breaking failure by tension and shear; the breaking failure by compression and shear; and the buckling failure by compression and shear. The first and the second modes of failures are almost independent of the types and the sizes of the bearings. The breaking conditions of those failure modes are described in the axial stress-shear strain plane. This expression is useful for the evaluation of safety margins of the bearings. The paper outlines the basic design of the nuclear-grade bearings which were used for large-scale rubber bearing tests in a research project for seismic isolation of fast breeder reactor (FBR) plants. The paper also discusses the protection method against aging and the quality control which are important for implementation

  13. A review of bear farming and bear trade in Lao People's Democratic Republic

    Directory of Open Access Journals (Sweden)

    E. Livingstone

    2018-01-01

    Full Text Available This study reviews the bear farming industry in Lao PDR with the objective of documenting the current number of commercial bear facilities (i.e. captive bear facilities judged to be trading in bear bile and/or bears and bear parts and the number of bears contained within these facilities, noting changes since it was last examined between 2000 and 2012 by Livingstone and Shepherd (2014. We surveyed all known commercial bear facilities and searched for previously unrecorded facilities. We compared our records with Livingstone and Shepherd (2014 and corrected some duplicate records from their study. In 2017, we recorded seven commercial facilities; four dedicated bear farms, and three tiger farms that were reportedly also keeping bears. We found that between 2012 and 2017 the recorded number of dedicated bear farms reduced by two, and the recorded number of tiger farms also keeping bears increased by one. Within the same period, the total number of captive bears among all facilities in Lao PDR hardly changed (+one, but the number of bears within each facility did. The northern facilities, owned by ethnic Chinese, have expanded since 2012, and central and southern facilities have downsized or closed. While bear farming appears to be downsizing in Lao PDR overall, efforts to phase it out are undermined by the expansion of foreign owned facilities in the north, within Special and Specific Economic Zones that largely cater to a Chinese market, and where the Lao government's efforts to enforce laws and protect wildlife appear to be lacking. Closing the facilities in the north will require political will and decisive law enforcement. Keywords: Bear farms, Bear bile, Gall bladder, Urso-deoxycholic acid, Bear bile extraction facilities, Lao PDR, Ursus thibetanus

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

    International Nuclear Information System (INIS)

    Passamai Junior, Jose Luis; Pinheiro, Christiano J.G.; Orlando, Marcos Tadeu D.; Passos, Carlos A.C.; Rossi, Jesualdo L.; Mazzocchi, Vera L.; Parente, Carlos B.R.; Mestnik Filho, Jose; Martinez, Luis G.; Melo, Francisco C.L. de

    2011-01-01

    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 4 C anvils in order to allow the low absorption of the radiation. The B 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 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 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)

  15. Volumetric Growth of the Liver in the Human Fetus: An Anatomical, Hydrostatic, and Statistical Study

    Directory of Open Access Journals (Sweden)

    Michał Szpinda

    2015-01-01

    Full Text Available Using anatomical, hydrostatic, and statistical methods, liver volumes were assessed in 69 human fetuses of both sexes aged 18–30 weeks. No sex differences were found. The median of liver volume achieved by hydrostatic measurements increased from 6.57 cm3 at 18–21 weeks through 14.36 cm3 at 22–25 weeks to 20.77 cm3 at 26–30 weeks, according to the following regression: y = −26.95 + 1.74 × age ± Z  × (−3.15 + 0.27 × age. The median of liver volume calculated indirectly according to the formula liver volume = 0.55 × liver length × liver transverse diameter × liver sagittal diameter increased from 12.41 cm3 at 18–21 weeks through 28.21 cm3 at 22–25 weeks to 49.69 cm3 at 26–30 weeks. There was a strong relationship (r=0.91, p<0.001 between the liver volumes achieved by hydrostatic (x and indirect (y methods, expressed by y = −0.05 + 2.16x  ± 7.26. The liver volume should be calculated as follows liver volume = 0.26 × liver length × liver transverse diameter × liver sagittal diameter. The age-specific liver volumes are of great relevance in the evaluation of the normal hepatic growth and the early diagnosis of fetal micro- and macrosomias.

  16. Volumetric Growth of the Liver in the Human Fetus: An Anatomical, Hydrostatic, and Statistical Study

    Science.gov (United States)

    Szpinda, Michał; Paruszewska-Achtel, Monika; Mila-Kierzenkowska, Celestyna; Elminowska-Wenda, Gabriela; Dombek, Małgorzata; Szpinda, Anna; Badura, Mateusz

    2015-01-01

    Using anatomical, hydrostatic, and statistical methods, liver volumes were assessed in 69 human fetuses of both sexes aged 18–30 weeks. No sex differences were found. The median of liver volume achieved by hydrostatic measurements increased from 6.57 cm3 at 18–21 weeks through 14.36 cm3 at 22–25 weeks to 20.77 cm3 at 26–30 weeks, according to the following regression: y = −26.95 + 1.74 × age ± Z  × (−3.15 + 0.27 × age). The median of liver volume calculated indirectly according to the formula liver volume = 0.55 × liver length × liver transverse diameter × liver sagittal diameter increased from 12.41 cm3 at 18–21 weeks through 28.21 cm3 at 22–25 weeks to 49.69 cm3 at 26–30 weeks. There was a strong relationship (r = 0.91, p hydrostatic (x) and indirect (y) methods, expressed by y = −0.05 + 2.16x  ± 7.26. The liver volume should be calculated as follows liver volume = 0.26 × liver length × liver transverse diameter × liver sagittal diameter. The age-specific liver volumes are of great relevance in the evaluation of the normal hepatic growth and the early diagnosis of fetal micro- and macrosomias. PMID:26413551

  17. Reversible Morphological Control of Tubulin-Encapsulating Giant Liposomes by Hydrostatic Pressure.

    Science.gov (United States)

    Hayashi, Masahito; Nishiyama, Masayoshi; Kazayama, Yuki; Toyota, Taro; Harada, Yoshie; Takiguchi, Kingo

    2016-04-19

    Liposomes encapsulating cytoskeletons have drawn much recent attention to develop an artificial cell-like chemical-machinery; however, as far as we know, there has been no report showing isothermally reversible morphological changes of liposomes containing cytoskeletons because the sets of various regulatory factors, that is, their interacting proteins, are required to control the state of every reaction system of cytoskeletons. Here we focused on hydrostatic pressure to control the polymerization state of microtubules (MTs) within cell-sized giant liposomes (diameters ∼10 μm). MT is the cytoskeleton formed by the polymerization of tubulin, and cytoskeletal systems consisting of MTs are very dynamic and play many important roles in living cells, such as the morphogenesis of nerve cells and formation of the spindle apparatus during mitosis. Using real-time imaging with a high-pressure microscope, we examined the effects of hydrostatic pressure on the morphology of tubulin-encapsulating giant liposomes. At ambient pressure (0.1 MPa), many liposomes formed protrusions due to tubulin polymerization within them. When high pressure (60 MPa) was applied, the protrusions shrank within several tens of seconds. This process was repeatedly inducible (around three times), and after the pressure was released, the protrusions regenerated within several minutes. These deformation rates of the liposomes are close to the velocities of migrating or shape-changing living cells rather than the shortening and elongation rates of the single MTs, which have been previously measured. These results demonstrate that the elongation and shortening of protrusions of giant liposomes is repeatedly controllable by regulating the polymerization state of MTs within them by applying and releasing hydrostatic pressure.

  18. Effect of upper body position on arterial stiffness: influence of hydrostatic pressure and autonomic function.

    Science.gov (United States)

    Schroeder, Elizabeth C; Rosenberg, Alexander J; Hilgenkamp, Thessa I M; White, Daniel W; Baynard, Tracy; Fernhall, Bo

    2017-12-01

    To evaluate changes in arterial stiffness with positional change and whether the stiffness changes are due to hydrostatic pressure alone or if physiological changes in vasoconstriction of the conduit arteries play a role in the modulation of arterial stiffness. Thirty participants' (male = 15, 24 ± 4 years) upper bodies were positioned at 0, 45, and 72° angles. Pulse wave velocity (PWV), cardio-ankle vascular index, carotid beta-stiffness index, carotid blood pressure (cBP), and carotid diameters were measured at each position. A gravitational height correction was determined using the vertical fluid column distance (mmHg) between the heart and carotid artery. Carotid beta-stiffness was calibrated using three methods: nonheight corrected cBP of each position, height corrected cBP of each position, and height corrected cBP of the supine position (theoretical model). Low frequency systolic blood pressure variability (LFSAP) was analyzed as a marker of sympathetic activity. PWV and cardio-ankle vascular index increased with position (P hydrostatic pressure. Arterial stiffness indices based on Method 2 were not different from Method 3 (P = 0.65). LFSAP increased in more upright positions (P pressure did not (P > 0.05). Arterial stiffness increases with a more upright body position. Carotid beta-stiffness needs to be calibrated accounting for hydrostatic effects of gravity if measured in a seated position. It is unclear why PWV increased as this increase was independent of blood pressure. No difference between Methods 2 and 3 presumably indicates that the beta-stiffness increases are only pressure dependent, despite the increase in vascular sympathetic modulation.

  19. Hydrostatic and uniaxial pressure effect on Tc of YBa2Cu3Ox

    International Nuclear Information System (INIS)

    Ludwig, H.A.; Quenzel, R.; Schlachter, S.I.

    1996-01-01

    The variation of the transition temperature T c of YBa 2 Cu 3 O x with hydrostatic He-gas pressure depends on the oxygen content x. The pressure effect dT c /dp increases from small negative values at x=7 to dT c /dp=7.4 K/GPa at x=6.7. For oxygen contents below x=6.7 dT c /dp drops to 3 K/GPa and remains nearly constant. The charge transfer model cannot explain the drop at x=6.7. Thermal expansion measurements on YBa 2 Cu 3 O x indicated that the uniaxial pressure effects along the three crystal axes are different. To investigate the uniaxial pressure effects inductively an experimental setup was constructed. The T c -change of several YBa 2 Cu 3 O x single crystals with different oxygen contents has been investigated under pressure along the c-axis. To avoid oxygen ordering processes the samples were held below 105 K during the measurements. The results of uniaxial pressure measurements in c-axis direction fit to former uniaxial pressure data and are explained within the charge transfer model. Hydrostatic pressure data of overdoped samples fit to the same curve. However, this is not the case for under doped samples. From this the authors conclude that only a part of the hydrostatic pressure effect can be explained by charge transfer in the underdoped region. The remaining part can be ascribed to uniaxial pressure effects along the a- and b-axis

  20. Recovery of tobacco BY-2 cells after high hydrostatic pressure treatment.

    Science.gov (United States)

    Kusube, Masataka; Nishino, Takumi; Nishikawa, Yuki; Goto, Masaki; Matsuki, Hitoshi; Iwahashi, Hitoshi

    2010-02-01

    The recovery of Nicotiana tabacum L. cv. Bright Yellow 2 (BY-2) cells in Linsmaire and Skoog medium after treatment at high hydrostatic pressure was investigated using an Evans Blue staining method to discriminate live from dead cells. The survival of BY-2 cells just after the high-pressure treatment at 5 degrees C and 25 degrees C decreased abruptly at pressures higher than 50 MPa and 100 MPa, respectively. Furthermore, almost all of the BY-2 cells treated at 5 degrees C and 25 degrees C recovered pressures below 25 MPa and 75 MPa, respectively. However, no BY-2 cells recovered at pressures above 100 MPa at either temperature.

  1. From Archimedean Hydrostatics to Post-Aristotelian Mechanics: Galileo's Early Manuscripts De motu antiquiora (ca. 1590)

    Science.gov (United States)

    Salvia, Stefano

    2017-06-01

    Galileo's early inquiries on motion and free fall in Pisa (1588-1592) can be regarded as a case study of multiple knowledge transfer at the very basic roots of modern mechanics. The treatise De motu, unpublished until 1890, is an original but unsuccessful attempt to go beyond Aristotelian physics by extending Archimedean hydrostatics to the dynamics of natural motion and reappraising the late-medieval impetus theory to account for violent motion and acceleration. I will discuss in particular why Galileo was forced to abandon his project before moving to Padua and how the manuscripts De motu provided him with a "research agenda" for further theoretical and experimental investigation.

  2. 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

  3. Reduced fuel consumption for fork-lift trucks with hydrostatic transmission

    Energy Technology Data Exchange (ETDEWEB)

    Abels, T

    1983-05-01

    Cost calculations for a 3,5-t diesel fork lifter done on the basis of VDI 2695 shows, that fuel costs account only for a small part of the operating costs despite the price increase for diesel fuel. Fork lifters with disk-cam controlled primary/secondary adjusted hydrostatic transmission used less fuel than was indicated in the VDI-guideline. Fuel consumption could further be reduced by an optimized hydraulic adjustment together with a precisely harmonized engine speed adjustment. Annual cost savings are considerable.

  4. A hydrostatic leak test for water pipeline by using distributed optical fiber vibration sensing system

    Science.gov (United States)

    Wu, Huijuan; Sun, Zhenshi; Qian, Ya; Zhang, Tao; Rao, Yunjiang

    2015-07-01

    A hydrostatic leak test for water pipeline with a distributed optical fiber vibration sensing (DOVS) system based on the phase-sensitive OTDR technology is studied in this paper. By monitoring one end of a common communication optical fiber cable, which is laid in the inner wall of the pipe, we can detect and locate the water leakages easily. Different apertures under different pressures are tested and it shows that the DOVS has good responses when the aperture is equal or larger than 4 mm and the inner pressure reaches 0.2 Mpa for a steel pipe with DN 91cm×EN 2cm.

  5. Effect of hydrostatic pressure on phase transformations in Kh17N8 steel during deformation

    International Nuclear Information System (INIS)

    Eshchenko, R.N.; Teplov, V.A.

    1984-01-01

    The phase composition and structure of Kh17N8 steel strained to different degrees under atmospheric pressure and 1700 MPa are investigated. It has been found that deformation at 1700 MPa causes α and epsilon-martensite formation, the same deformation under atmospheric pressure - only α-martensite formation. The amount of the formed α-martensite is not changed with application of hydrostatic pressure. Electron-microscopic observations have shown that the dispersion of α-martensite formed under pressure is higher than in the absence of pressure; no interconnection in formation of α and epsilon-martensite in samples strained under pressure has been observed

  6. Dynamic tuning by hydrostatic pressure of magnetocaloric properties to Ericsson like cycles

    Science.gov (United States)

    Gaztañaga, P.; Sacanell, J.; Leyva, A. G.; Quintero, M.

    2018-03-01

    A method to increase the relative cooling power to be used in Ericsson like refrigeration cycles is presented. The technique is based in the modification of the magnetic properties by the application of hydrostatic pressure on magnetic samples. The main advantage is to reach larger values of the magnetic entropy change in a wider temperature region (the so-called "table like" behavior). The study was carried out in a manganite belonging to the family of La0.625-yNdyCa0.375MnO3, and some conclusions were compared with the expected behavior in other materials extracted from literature.

  7. The decrease in yield strength in NiAl due to hydrostatic pressure

    Science.gov (United States)

    Margevicius, R. W.; Lewandowski, J. J.; Locci, I.

    1992-01-01

    The decrease in yield strength in NiAl due to hydrostatic pressure is examined via a comparison of the tensile flow behavior in the low strain regime at 0.1 MPa for NiAl which was cast, extruded, and annealed for 2 hr at 827 C in argon and very slowly cooled to room temperature. Pressurization to 1.4 GPa produces a subsequent reduction at 0.1 MP in proportional limit by 40 percent as well as a 25-percent reduction in the 0.2-percent offset yield strength, while pressurization with lower pressures produces a similar reduction, although smaller in magnitude.

  8. Three-Dimensional Digital Image Correlation of a Composite Overwrapped Pressure Vessel During Hydrostatic Pressure Tests

    Science.gov (United States)

    Revilock, Duane M., Jr.; Thesken, John C.; Schmidt, Timothy E.

    2007-01-01

    Ambient temperature hydrostatic pressurization tests were conducted on a composite overwrapped pressure vessel (COPV) to understand the fiber stresses in COPV components. Two three-dimensional digital image correlation systems with high speed cameras were used in the evaluation to provide full field displacement and strain data for each pressurization test. A few of the key findings will be discussed including how the principal strains provided better insight into system behavior than traditional gauges, a high localized strain that was measured where gages were not present and the challenges of measuring curved surfaces with the use of a 1.25 in. thick layered polycarbonate panel that protected the cameras.

  9. The calculation of hydrostatic pressures in SIMMER-II and the problem of connected tubes

    International Nuclear Information System (INIS)

    Schmuck, P.; Kleinheins, S.

    1986-03-01

    Some SIMMER-II calculations had shown that the hydrostatic equilibrium in connected tubes had not been simulated correctly under certain conditions. The present report documents the results of the investigations, which had been performed to understand these inconsistencies. The reasons are presented in analytical form and possibilities to avoid the mistakes or to keep their consequences as small as possible are given. For the verification of the analytical results some SIMMER-II, version 9 have been performed and their results are presented

  10. Electron beam melting of bearing materials

    Energy Technology Data Exchange (ETDEWEB)

    Goldschmied, G.; Schuler, A. (Technische Univ., Vienna (Austria). Inst. fuer Allgemeine Elektrotechnik); Elsinger, G.; Koroschetz, F. (MIBA Gleitlager AG, Laakirchen (Austria)); Tschegg, E.K. (Technische Univ., Vienna (Austria). Inst. fuer Angewandte und Technische Physik)

    1990-06-01

    This paper reports on a surface treatment method for the bearing materials AlSn6 which permits the use of this material without the overlay usually required. Microstructural refinement is achieved by means of a surface melting technique using an electron beam with successive rapid solidification. Extremely fine tin precipitates are formed in the melted surface layer which lead to significantly better tribological properties of the bearing material. Tests compared the tribological properties for AlSn6 bearings treated by the surface melting technique with those of untreated bearings. Whereas all untreated bearings failed by seizure after only 2 h of testing, 30% of the tested bearings which had been surface melted survived the entire testing program without damage.

  11. Bearing Health Assessment Based on Chaotic Characteristics

    Directory of Open Access Journals (Sweden)

    Chen Lu

    2013-01-01

    Full Text Available Vibration signals extracted from rotating parts of machinery carry a lot of useful information about the condition of operating machine. Due to the strong non-linear, complex and non-stationary characteristics of vibration signals from working bearings, an accurate and reliable health assessment method for bearing is necessary. This paper proposes to utilize the selected chaotic characteristics of vibration signal for health assessment of a bearing by using self-organizing map (SOM. Both Grassberger-Procaccia algorithm and Takens' theory are employed to calculate the characteristic vector which includes three chaotic characteristics, such as correlation dimension, largest Lyapunov exponent and Kolmogorov entropy. After that, SOM is used to map the three corresponding characteristics into a confidence value (CV which represents the health state of the bearing. Finally, a case study based on vibration datasets of a group of testing bearings was conducted to demonstrate that the proposed method can reliably assess the health state of bearing.

  12. Effect of chemical pressure, misfit strain and hydrostatic pressure on structural and magnetic behaviors of rare-earth orthochromates

    International Nuclear Information System (INIS)

    Zhao, Hong Jian; Chen, Xiang Ming; Ren, Wei; Bellaiche, L

    2013-01-01

    First-principles calculations are performed to investigate structural and magnetic behaviors of rare-earth orthochromates as a function of ‘chemical’ pressure (that is, the rare-earth ionic radius), epitaxial misfit strain and hydrostatic pressure. From a structural point of view, (i) ‘chemical’ pressure significantly modifies antipolar displacements, Cr–O–Cr bond angles and the resulting oxygen octahedral tiltings; (ii) hydrostatic pressure mostly changes Cr–O bond lengths; and (iii) misfit strain affects all these quantities. The correlations between magnetic properties (Néel temperature and weak ferromagnetic moments) and unit cell volume are similar when varying the misfit strain or hydrostatic pressure, but differ from those associated with the ‘chemical’ pressure. Origins of such effects are also discussed. (paper)

  13. Effect of hydrostatic pressure on photoluminescence spectra from structures with Si nanocrystals fabricated in SiO2 matrix

    International Nuclear Information System (INIS)

    Zhuravlev, K.S.; Tyschenko, I.E.; Vandyshev, E.N.; Bulytova, N.V.; Misiuk, A.; Rebohle, L.; Skorupa, W.

    2002-01-01

    The effect of hydrostatic pressure applied at high temperature on photoluminescence of Si-implanted SiO 2 films was studied. A 'blue'-shift of PL spectrum from the SiO 2 films implanted with Si + ions to total dose of 1.2x10 17 cm -2 with increase in hydrostatic pressure was observed. For the films implanted with Si + ions to a total dose of 4.8x10 16 cm -2 high temperature annealing under high hydrostatic pressure (12 kbar) causes a 'red'-shift of photoluminescence spectrum. The 'red' photoluminescence bands are attributed to Si nanocrystals while the 'blue' ones are related to Si nanocrystals of reduced size or chains of silicon atoms or Si-Si defects. A decrease in size of Si nanocluster occurs in result of the pressure-induced decrease in the diffusion of silicon atoms. (author)

  14. Effect of hydrostatic pressure application at cryogenic temperatures on the properties of VT1-0 alloy

    International Nuclear Information System (INIS)

    Khajmovich, P.A; Shulgin, N.A.; Chernyaeva, E.V.

    2015-01-01

    Attempt was made to determine the influence of hydrostatic pressure on the properties of the alloy VT1-0 at cryogenic temperatures both under straining of the alloy and without it. Hardening of the material is observed only in that part of the specimen, which experienced a deformation, while the very exposure of the alloy under hydrostatic pressure does not lead to strengthening of the material. At the same time, measurements of acoustic emission (AE) show that in the near-surface layers the forces of hydrostatic compression alone, i.e. without a deformation, cause some changes in the structure, which stipulate an increase of the energy and (to a lesser extent) of the median frequency of AE signals. An explanation of this phenomenon is suggested

  15. The influence of hydrostatic pressure on the electronic structure and optical properties of tin dioxide: A first-principle study

    International Nuclear Information System (INIS)

    Cai Lugang; Liu Famin; Zhang Dian; Zhong Wenwu

    2013-01-01

    The evolutions of electronic structure and optical properties of SnO 2 under hydrostatic pressure are studied theoretically using first-principle calculations. The calculation results show that the energy band gap of SnO 2 expands with increasing pressure, and the relationship between them can be fitted well by a second order polynomial expression. The complex dielectric functions are calculated and it is found that its imaginary part moves to higher photon energy levels with increasing pressure; meanwhile the static dielectric function constant decreases correspondingly. The dependences of other optical properties, such as the reflectivity spectra and loss function, on the hydrostatic pressure are also calculated and obtained, and the relationships between the optical properties and hydrostatic pressure are discussed and analyzed.

  16. Trends in Controllable Oil Film Bearings

    DEFF Research Database (Denmark)

    Santos, Ilmar

    2011-01-01

    This work gives an overview about the theoretical and experimental achievements of mechatronics applied to oil film bearings, with the aim of: controlling the lateral vibration of flexible rotating shafts; modifying bearing dynamic characteristics, as stiffness and damping properties; increasing......" components and be applied to rotating machines with the goal of avoiding unexpected stops of plants, performing rotordynamic tests and identifying model parameters "on site". Emphasis is given to the controllable lubrication (active lubrication) applied to different types of oil film bearings, i...

  17. Analysis and investigation of temperature and hydrostatic pressure effects on optical characteristics of multiple quantum well slow light devices.

    Science.gov (United States)

    Abdolhosseini, Saeed; Kohandani, Reza; Kaatuzian, Hassan

    2017-09-10

    This paper represents the influences of temperature and hydrostatic pressure variations on GaAs/AlGaAs multiple quantum well slow light systems based on coherence population oscillations. An analytical model in non-integer dimension space is used to study the considerable effects of these parameters on optical properties of the slow light apparatus. Exciton oscillator strength and fractional dimension constants have special roles on the analytical model in fractional dimension. Hence, the impacts of hydrostatic pressure and temperature on exciton oscillator strength and fractional dimension quantity are investigated theoretically in this paper. Based on the achieved results, temperature and hydrostatic pressure play key roles on optical parameters of the slow light systems, such as the slow down factor and central energy of the device. It is found that the slope and value of the refractive index real part change with alterations of temperature and hydrostatic pressure in the range of 5-40 deg of Kelvin and 1 bar to 2 kbar, respectively. Thus, the peak value of the slow down factor can be adjusted by altering these parameters. Moreover, the central energy of the device shifts when the hydrostatic pressure is applied to the slow light device or temperature is varied. In comparison with previous reported experimental results, our simulations follow them successfully. It is shown that the maximum value of the slow down factor is estimated close to 5.5×10 4 with a fine adjustment of temperature and hydrostatic pressure. Meanwhile, the central energy shift of the slow light device rises up to 27 meV, which provides an appropriate basis for different optical devices in which multiple quantum well slow light is one of their essential subsections. This multiple quantum well slow light device has potential applications for use as a tunable optical buffer and pressure/temperature sensors.

  18. Lens intracellular hydrostatic pressure is generated by the circulation of sodium and modulated by gap junction coupling

    Science.gov (United States)

    Gao, Junyuan; Sun, Xiurong; Moore, Leon C.; White, Thomas W.; Brink, Peter R.

    2011-01-01

    We recently modeled fluid flow through gap junction channels coupling the pigmented and nonpigmented layers of the ciliary body. The model suggested the channels could transport the secretion of aqueous humor, but flow would be driven by hydrostatic pressure rather than osmosis. The pressure required to drive fluid through a single layer of gap junctions might be just a few mmHg and difficult to measure. In the lens, however, there is a circulation of Na+ that may be coupled to intracellular fluid flow. Based on this hypothesis, the fluid would cross hundreds of layers of gap junctions, and this might require a large hydrostatic gradient. Therefore, we measured hydrostatic pressure as a function of distance from the center of the lens using an intracellular microelectrode-based pressure-sensing system. In wild-type mouse lenses, intracellular pressure varied from ∼330 mmHg at the center to zero at the surface. We have several knockout/knock-in mouse models with differing levels of expression of gap junction channels coupling lens fiber cells. Intracellular hydrostatic pressure in lenses from these mouse models varied inversely with the number of channels. When the lens’ circulation of Na+ was either blocked or reduced, intracellular hydrostatic pressure in central fiber cells was either eliminated or reduced proportionally. These data are consistent with our hypotheses: fluid circulates through the lens; the intracellular leg of fluid circulation is through gap junction channels and is driven by hydrostatic pressure; and the fluid flow is generated by membrane transport of sodium. PMID:21624945

  19. Technical Development Path for Gas Foil Bearings

    Science.gov (United States)

    Dellacorte, Christopher

    2016-01-01

    Foil gas bearings are in widespread commercial use in air cycle machines, turbocompressors and microturbine generators and are emerging in more challenging applications such as turbochargers, auxiliary power units and propulsion gas turbines. Though not well known, foil bearing technology is well over fifty years old. Recent technological developments indicate that their full potential has yet to be realized. This paper investigates the key technological developments that have characterized foil bearing advances. It is expected that a better understanding of foil gas bearing development path will aid in future development and progress towards more advanced applications.

  20. Non-Invasive Parameter Identification in Rotordynamics via Fluid Film Bearings: Linking Active Lubrication and Operational Modal Analysis

    DEFF Research Database (Denmark)

    Santos, Ilmar; Svendsen, Peter Kjær

    2017-01-01

    the rotor as a function of a suitable control signal. The servovalve input signal and the radial injection pressure are the two main parameters responsible for dynamically modifying the journal oil film pressure and generating active fluid film forces in controllable fluid film bearings. Such fluid film...... forces, resulting from a strong coupling between hydrodynamic, hydrostatic and controllable lubrication regimes, can be used either to control or to excite rotor lateral vibrations. If non-invasive forces are generated via lubricant fluid film, in situ parameter identification can be carried out......, enabling evaluation of the mechanical condition of the rotating machine. Using the lubricant fluid film as a non-invasive calibrated shaker is troublesome, once several transfer functions among mechanical, hydraulic and electronic components become necessary. In this framework the main original...