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1

Hydrostatic bearings for a turbine fluid flow metering device  

DOEpatents

A rotor assembly fluid metering device has been improved by development of a hydrostatic bearing fluid system which provides bearing fluid at a common pressure to rotor assembly bearing surfaces. The bearing fluid distribution system produces a uniform film of fluid between bearing surfaces and allows rapid replacement of bearing fluid between bearing surfaces, thereby minimizing bearing wear and corrosion.

Fincke, James R. (Rigby, ID)

1982-01-01

2

Hydrostatic bearings for a turbine fluid flow metering device  

DOEpatents

A rotor assembly fluid metering device has been improved by development of a hydrostatic bearing fluid system which provides bearing fluid at a common pressure to rotor assembly bearing surfaces. The bearing fluid distribution system produces a uniform film of fluid distribution system produces a uniform film of fluid between bearing surfaces and allows rapid replacement of bearing fluid between bearing surfaces, thereby minimizing bearing wear and corrosion.

Fincke, J.R.

1980-05-02

3

A Porous Hydrostatic Gas Bearing for Use in Miniature Turbomachinery  

Microsoft Academic Search

An analytical program was conducted to establish recommended types of gas-lubricated journal bearings for use in miniature cryogenic turbomachinery. Very high rotative speeds, and the limiting damping properties of gas, indicated that fractional frequency whirl is prevalent, and the most difficult problem to overcome. Of the many journal bearing types investigated, the tilting pad hydro-dynamic and porous hydrostatic journal bearings

S. Heller; W. Shapiro; O. Decker

1971-01-01

4

Error correction in hydrostatic spindles by optimal bearing tuning  

Microsoft Academic Search

In this paper a high precision grinding wheel is considered as a rigid rotor mounted on two hydrostatic bearings. The equations for small perturbations of the wheel on the bearings are derived in the form of a multi-input, multi-output transfer function matrix, enabling the frequency response function of the wheel to be determined. Thereafter an optimisation algorithm is proposed which

M. Aleyaasin; R. Whalley; M. Ebrahimi

2000-01-01

5

Analysis of hydrostatic journal bearings with end seals  

NASA Astrophysics Data System (ADS)

An approximate analysis for the pressure field and dynamic force coefficients in turbulent flow, centered hydrostatic journal bearings (HJBs) with fluid inertia and liquid compressibility effects is presented. Results from the analysis show that HJBs with end seals have increased damping, better dynamic stability characteristics, as well as lower flow rates, than conventional HJBs. However, hydrostatic (direct) stiffness may be lost if excessively tight end seals are used. End seals are shown to compensate for the effect of liquid compressibility within the recess volume, and prescribe a net reduction in the whirl frequency ratio for hybrid operation. Hydrostatic squeeze film dampers (HSFD) with end seals are shown to be a viable alternative in applications where a tight control of the bearing leakage is important such as in jet-engines. Furthermore, HSFDs with end seals could be used as an active device to control the available damping in a typical application.

San Andres, L. A.

1992-10-01

6

Long-Term Bearing Wear Tests of Conventional Journal Bearings and Development of Hydrostatic Bearings for the LOFT Drag-Disc Turbine Transducer.  

National Technical Information Service (NTIS)

The details of a two-year development program concerning materials for use as turbine bearings in a pressurized water reactor environment are reported. Two types of bearings have been examined, both conventional journal bearings and hydrostatic bearings. ...

J. R. Fincke

1979-01-01

7

DEVELOPMENT OF A HYDROSTATIC JOURNAL BEARING WITH SLIT-STEP COMPENSATION  

SciTech Connect

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

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

2006-07-28

8

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

Microsoft Academic Search

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

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

1992-01-01

9

A parameter identification method for the rotordynamic coefficients of a high Reynolds number hydrostatic bearing  

NASA Astrophysics Data System (ADS)

In identifying the rotordynamic coefficients of a high-Reynolds-number hydrostatic bearing, fluid-flow induced forces present a unique problem, in that they provide an unmeasureable and uncontrollable excitation to the bearing. An analysis method is developed that effectively eliminates the effects of fluid-flow induced excitation on the estimation of the bearing rotordynamic coefficients, by using power spectral densities. In addition to the theoretical development, the method is verified experimentally by single-frequency testing, and repeatability tests. Results obtained for a bearing are the twelve rotordynamic coefficients (stiffness, damping, and inertia coefficients) as functions of eccentricity ratio, speed, and supply pressure.

Rouvas, C.; Childs, D. W.

1993-07-01

10

Comparative study of the performance on a constant flow annular hydrostatic thrust bearing having multi-circular recess and sector recess  

Microsoft Academic Search

A theoretical comparative study concerning performance of a constant flow hydrostatic thrust bearing having multi-circular recess and sector recess is described. The Computational Fluid Dynamics and the Finite Volume Method have been used to compute the characteristics of a constant fluid hydrostatic thrust bearing with circular and sector recesses. The performance has been compared, namely, recess pressure, pressure distribution and

Xiaodong Yu; Xiuli Meng; Junpeng Shao; Yanqin Zhang; Bo Wu; Zhimin Shi

2009-01-01

11

Parameter identification of the rotordynamic coefficients of high-Reynolds-number hydrostatic bearings  

NASA Astrophysics Data System (ADS)

The research presented here concentrates on experimental and analytical methods to identify the twelve rotordynamic coefficients of high-Reynolds-number hydrostatic bearings. Fluid-flow-induced noise (turbulence, cavitation) presents a significant problem in testing these bearings, since this noise exists in the same frequency range as the test signals. This common frequency range eliminates the possibility of rejecting the noise through filtering. A frequency-domain analysis method has been developed to extract the rotordynamic coefficients from data obtained by multi-frequency sequential excitation testing. Power-spectral-density estimates are used to reject noise that is independent of the applied excitation. The method is verified experimentally by single-frequency excitation, and repeatability tests. A second power-spectral-density based identification method has been developed and applied to simultaneous excitation test data. Here, two independent random excitations are applied simultaneously to the bearing, and their effects are separated by computing appropriate power-spectral-density estimates, while, at the same time, maintaining excellent noise rejection properties. This method yields results identical to the sequential excitation procedure, and reduces the actual test and analysis times by one half. Last, an analysis method in the time domain has been developed and implemented. In essence it is a direct application of least squares to the bearing housing equations of motion. For this method, it is shown that for the low-frequency noise present in the measurements, differentiation of the signals is acceptable, and preferable over integration. The twelve rotordynamic coefficients are obtained from a recursive formulation of least squares, and the results are shown to have acceptable convergence. Also, the coefficients extracted from this method are found to reconstruct the bearing response more accurately than the coefficients extracted from the power-spectral-density methods.

Rouvas, Constantinos

12

A new type of hydrostatic\\/hydrodynamic gas journal bearing and its optimization for maximum stability  

Microsoft Academic Search

The orifice annular and shallow pocket restricted hybrid has journal bearing is a new type of gas bearing which has good high-speed stability performance. In this paper, the stability of this bearing with three shallow pockets is studied theoretically, and the optimization for its maximum stability is carried out by use of the Complex Method. Some useful conclusions are obtained.

Rui-Qian Zhang; H. S. Chang

1995-01-01

13

A new type of hydrostatic/hydrodynamic gas journal bearing and its optimization for maximum stability  

SciTech Connect

The orifice annular and shallow pocket restricted hybrid has journal bearing is a new type of gas bearing which has good high-speed stability performance. In this paper, the stability of this bearing with three shallow pockets is studied theoretically, and the optimization for its maximum stability is carried out by use of the Complex Method. Some useful conclusions are obtained.

Zhang, R.; Chang, H.S. [Beijing Univ. of Aeronautics and Astronautics, Beijing (China)

1995-07-01

14

Stability of a New Type of Hydrostatic\\/Hydrodynamic Floating Ring Gas Bearing  

Microsoft Academic Search

In this paper, a new type of floating ring gas bearing in which a “floating ring” is combined with an “orifice-annular and shallow-pocket” gas bearing is introduced. The stability of this new type of floating ring gas journal bearing is theoretically analyzed by use of the modified 8-stiffness and damping coefficients method. The variation of the dimensionless critical mass of

Rui-Qian Zhang; H. S. Chang

1999-01-01

15

Hotfire testing of a SSME HPOTP with an annular hydrostatic bearing  

NASA Astrophysics Data System (ADS)

A new fluid film bearing package has been tested in the Space Shuttle Main Engine (SSME) High Pressure Oxygen Turbopump (HPOTP). This fluid film element functions as both the pump end bearing and the preburner pump rear wear ring seal. Most importantly, it replaces a duplex ball bearing package which has been the primary life limiting component in the turbopump. The design and predicted performance of the turbopump are reviewed. Results are presented for measured pump and bearing performance during testing on the NASA Technology Test Bed (TTB) Engine located at MSFC. The most significant results were obtained from proximity probes located in the bearing bore which revealed large subsynchronous precession at ten percent of shaft speed during engine start which subsided prior to mainstage power levels and reappeared during engine shutdown at equivalent power levels below 65% of nominal. This phenomenon has been attributed to rotating stall in the diffuser. The proximity probes also revealed the location of the bearing in the bore for different operating speeds. Pump vibration characteristics were improved as compared to pumps tested with ball bearings. After seven starts and more than 700 seconds of testing, the pump showed no signs of performance degradation.

Nolan, Steven A.; Hibbs, Robert I.; Genge, Gary G.

1994-01-01

16

Hotfire testing of a SSME HPOTP with an annular hydrostatic bearing  

NASA Astrophysics Data System (ADS)

A new fluid film bearing package has been tested in the SSME High Pressure Oxygen Turbopump (HPOTP). This fluid film element functions as both the pump end bearing and the preburner pump rear wear ring seal. Most important, it replaces a duplex ball bearing package which has been the primary life limiting component in the turbopump. The design and predicted performance of the turbopump are reviewed. Results are presented for measured pump and bearing performance. The most significant results were obtained from proximity probes located in the bearing bore which revealed large subsynchronous precession at 10 percent of shaft speed during engine start which subsided prior to mainstage power levels and reappeared during engine shutdown at equivalent power levels below 65 percent of nominal. This phenomenon has been attributed to rotating stall in the diffuser. The proximity probes also revealed the location of the bearing in the bore for different operating speeds. Pump vibration characteristics were improved as compared to pumps tested with ball bearings. After seven starts and more than 700 seconds of testing, the pump showed no signs of performance degradation.

Nolan, Steven A.; Hibbs, Robert I.; Genge, Gary G.

1993-06-01

17

The 3,6 m Indo-Belgian Devasthal Optical Telescope: the hydrostatic azimuth bearing  

NASA Astrophysics Data System (ADS)

AMOS SA has been awarded of the contract for the design, manufacturing, assembly, tests and on site installation (Devasthal, Nainital in central Himalayan region) of the 3.6 m Indo-Belgian Devasthal Optical Telescope (IDOT). The telescope has a Ritchey-Chrétien optical configuration with a Cassegrain focus equipped with one axial port and two side ports. The primary mirror is a meniscus active mirror. The mount is an Alt-Az type with for the azimuth axis a 5 m diameter hydrostatic track. This paper presents the solution adopted by AMOS to meet the specific requirements for the azimuth axis. The track is designed to be able to control the positioning of the telescope around the azimuth axis with an accuracy of 0.05 arc second for all tracking configurations. The challenge came from this tight accuracy with a mass in rotation weighting 125 tons. The azimuth track was mounted and tested in AMOS workshop; the tests and performances are also discussed.

de Ville, Jonathan; Piérard, Maxime; Bastin, Christian

2012-09-01

18

Bearings.  

National Technical Information Service (NTIS)

The bibliography is a collection of references on bearings. The references are sequenced numerically within the following topics: 1. Airframe Bearings, 2. Ball Bearings, 3. Roller Bearings, 4. Antifriction Bearings, 5. Gas Bearings, 6. Journal Bearings. 7...

1973-01-01

19

Bears  

NSDL National Science Digital Library

What are the characteristics of grizzly/brown bears and black bears? As you view the websites, please use this chart to record what you are learning about grizzly bears and black bears. For each bear, you should list 5 characteristics. Grizzly Bear and Black Bear Chart We will first begin by learning about black bears. Please go to these websites to learn some important facts about black bears. Black Bears Facts and Image Black Bear Facts for Kids Now that you have learned ...

Bledsoe, Miss

2011-04-07

20

Bears, Bears, Bears!  

NSDL National Science Digital Library

What are some things you learned about bears? Use these websites to find out about bears: Parts of a Bear Polar Bears Real Story of the Three Bears The truth about bears Brown Bears Now fill in your chart! Bear Fact Sheet Listen to your teacher for further instruction on completing a book about bears! ...

Ms.beason

2011-04-16

21

The Giant Magellan Telescope (GMT): hydrostatic constraints  

NASA Astrophysics Data System (ADS)

The Giant Magellan Telescope (GMT) is an optical-infrared 25 Meter ELT to be located in Chile. It is being designed and constructed by a group of U.S. and international universities and research institutions1. Structural performance of large telescopes can be enhanced significantly with the added stiffness that results from distributing loads to many points in the structure. In defining the two rotating assemblies in an altitude-over-azimuth mount more than a kinematic set of constraints can lead to hydrostatic bearing oil film failure due to unintended forces that result from runner bearing irregularities. High Frequency Over Constraint (HFOC) increases stiffness without risk of oil film failure. It was used successfully on the Magellan 6.5 Meter Telescopes. GMT will employ this and two additional methods to enhance stiffness at frequencies from DC wind up through the telescope primary mode frequencies of ~11 Hz. This will be achieved without excessive hydrostatic bearing pad forces. Detailed discussion of GMT's hydrostatic constraints, azimuth track and optics support structure (OSS) runner bearing illustrations, and performance criteria are provided for the design.

Gunnels, Steve

2010-07-01

22

A Hydrostatic Paradox Revisited  

ERIC Educational Resources Information Center

|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…

Ganci, Salvatore

2012-01-01

23

A Hydrostatic Paradox Revisited  

ERIC Educational Resources Information Center

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…

Ganci, Salvatore

2012-01-01

24

Maintenance of hydrostatic transmissions  

NASA Astrophysics Data System (ADS)

Problems in hydrostatic transmission maintenance are identified and ways of overcoming them are suggested. It is found that problems arise from lack of lubrication, impurities in the oil, and cavitation at the pump and at the motor. It is under suggested that under nonsevere operating conditions, oil and filter should be changed every year, or every 1500 to 2000 hr running time. Under severe operating conditions or in dusty environments, the interval should be every 6 months or 1000 hr.

Esposito, A.

1981-10-01

25

NASA Antenna Gets its Bearings  

NASA Video Gallery

The historic "Mars antenna" at NASA's Deep Space Network site in Goldstone, Calif. has finished a major, delicate surgery that lasted seven months. The operation on the giant, 70-meter-wide (230-foot) antenna replaced the hydrostatic bearing assembly, which enables the antenna to rotate horizontally, and the elevation bearings, which enable the antenna to track up and down from the horizon.

Luis Espinoza

2010-11-01

26

Rhea's Evolution: Undifferentiated? Hydrostatic?  

NASA Astrophysics Data System (ADS)

Measurements by the Cassini spacecraft have yielded Rhea's degree-two, gravity coefficients (Anderson and Schubert, GRL 34, 2007). Assuming that Rhea is in hydrostatic equilibrium, these authors have inferred that Rhea is undifferentiated. On the contrary, we find that Rhea is probably at least partially differentiated and should not be in hydrostatic equilibrium. We have run coupled thermophysical-dynamical evolution models of Rhea using the approach of Castillo-Rogez et al. (Icarus 190, 2007). We find that even in the "coldest” possible model for Rhea, some differentiation occurs early in the satellite's history. This is accompanied by eccentricity damping that prevents significant, long-term tidal heating. Warmer models provide an environment conducive to geological activity, consistent with recent high-resolution mapping of the satellite (Schenk and Moore, LPS 38, 2007). Our models also yield the current orbital properties for Rhea and provide a rationale for non-hydrostatic anomalies. These could affect the gravity measurements due to Rhea's shape being frozen early in its history. Its dynamical properties subsequently evolved. Thus a fossil bulge is expected. A major uncertainty in interpreting the gravity data comes from potential large-scale topographic anomalies. The current uncertainty in the shape measurements is about 1.7 km. If Rhea has a large-scale topographic anomaly of that amplitude, that anomaly would swamp part of the gravity signal, and prevent meaningful interpretation. More measurements of Rhea's gravity field as well as refined shape data are needed to improve our understanding of Rhea's interior and thus to further constrain the orbital and thermal history of this satellite. This work was carried out at the Jet Propulsion Laboratory-California Institute of Technology, under contract to NASA.

Matson, Dennis L.; Castillo-Rogez, J.; Johnson, T. V.

2007-10-01

27

Hydrostatic Adjustment: Lamb's Problem.  

NASA Astrophysics Data System (ADS)

The prototype problem of hydrostatic adjustment for large-scale atmospheric motions is Presented. When a horizontally infinite layer of compressible fluid, initially at rest, is instantaneously heated, the fluid is no longer in hydrostatic balance since its temperature and pressure in the layer have increased while its density remains unchanged. The subsequent adjustment of the fluid is described in detail for an isothermal base-state atmosphere.The initial imbalance generates acoustic wave fronts with trailing wakes of dispersive acoustic gravity waves. There are two characteristic timescales of the adjustment. The first is the transit time it takes an acoustic front to travel from the source region to a particular location. The second timescale, the acoustic cutoff frequency, is associated with the trailing wake. The characteristic depth scale of the adjustment is the density scale height. If the depth of the heating is small compared with the scale height, the final pressure perturbation tends to zero and the pressure field adjusts to the initial density hold. For larger depths, there is a mutual adjustment of the pressure and density fields.Use of the one-dimensional analogue of the conservation of Ertel's potential vorticity removes hydrostatic degeneracy and determines the final equilibrium state directly. As a result of the adjustment process, the heated layer has expanded vertically. Since the region below the layer is unaltered, the region aloft is displaced upward uniformly. As a consequence of the expansion, the pressure and temperature anomalies in the layer are reduced from their initial values immediately after the heating. Aloft both the pressure and density fields are increased but there is no change in temperature. Since the base-state atmosphere is isothermal, warm advection is absent; since the vertical displacements of air parcels is uniform aloft, compressional warming is also absent.The energetics of the adjustment are documented. Initially all the perturbation energy resides in the heated layer with a fraction [ggr]1 = 71.4% stored as available potential energy, while the remainder is available elastic energy, A fraction = R/Cp = ([ggr] 1)/ = 28.6% of the initial energy is lost to propagating acoustic modes. Here [ggr] = Cp/Cv is the ratio of the specific heats and R is the ideal gas constant. The remainder of the energy is partitioned between the heated layer and the region aloft. The energy aloft appears mostly as elastic energy, and the energy in the layer appears mostly as available potential energy.

Bannon, Peter R.

1995-05-01

28

Influence of rheological properties of a lubricant on power consumption and heat transfer in a hydrostatic lubricating layer  

SciTech Connect

The influence of rheological properties of lubricants on power consumption for pumping the lubricant in a hydrostatic lubricating layer and heat transfer of the lubricant with the supporting surfaces of a bearing is studied.

Yablonskii, V.O.; Tyabin, N.V.; Yashchuk, V.M.

1995-06-01

29

Hydroinertia gas bearings for micro spinners  

NASA Astrophysics Data System (ADS)

Externally pressurized gas bearings with large bearing clearance are successfully used in ultra-high-speed micro spinners. For example, a micro spinner 4 mm in diameter is stably operated at more than 20 krps and its whirl ratio exceeds 20. In such bearings, the inertia effect of the gas flow in bearing clearance becomes predominant and its Mach number exceeds 1. As a result, gas pressure in the bearing clearance becomes negative. These bearings are called hydroinertia gas bearings, in contrast to the conventional hydrostatic gas bearings. Static characteristics of hydroinertia gas bearings are analyzed by considering the viscous effect of gas as wall friction, and the optimum design of hydroinertia gas bearings is shown. Experimental results on micro spinners and trial design of hydroinertia gas bearings for micro gas turbines are also discussed.

Hikichi, Kousuke; Goto, Satoshi; Togo, Shinichi; Tanaka, Shuji; Isomura, Kousuke

2005-09-01

30

Deep water hydrostatic head control  

SciTech Connect

Hydrostatic head control in the marine riser or sub-sea BOP stack of a deep water drilling unit is maintained through use of an eductor, or similar means, connected to the sub-sea BOP stack choke line for drawing salt water from the sea or mud from the sub-sea BOP stack kill line.

Sykora, J.H.

1984-01-24

31

Deep water hydrostatic head control  

SciTech Connect

Hydrostatic head control in the marine riser or sub-sea BOP stack of a deep water drilling unit is maintained through use of an eductor, or similar means, connected to the sub-sea BOP stack kill line for drawing salt water from the sea or mud from the sub-sea BOP stack choke line.

Sykora, J. H.

1985-01-29

32

The Hydrostatic Gas Noncontact Seal  

Microsoft Academic Search

Hydrostatic gas noncontact seals are becoming more widely used as high-speed shaft seals for gas turbomachinery. Previous work for incompressible flow has been adapted to cover the gas flow dynamics of a hybrid taper\\/flat face seal, and the equivalent annular arrangement.The seal gap stability is discussed, along with various tests to confirm performance. The gas flow characteristics based on analysis

Tadashi Koga; Takuya Fujita

1986-01-01

33

Hydrostatic compaction of Microtherm HT.  

SciTech Connect

Two samples of jacketed Microtherm{reg_sign}HT were hydrostatically pressurized to maximum pressures of 29,000 psi to evaluate both pressure-volume response and change in bulk modulus as a function of density. During testing, each of the two samples exhibited large irreversible compactive volumetric strains with only small increases in pressure; however at volumetric strains of approximately 50%, the Microtherm{reg_sign}HT stiffened noticeably at ever increasing rates. At the maximum pressure of 29,000 psi, the volumetric strains for both samples were approximately 70%. Bulk modulus, as determined from hydrostatic unload/reload loops, increased by more than two-orders of magnitude (from about 4500 psi to over 500,000 psi) from an initial material density of {approx}0.3 g/cc to a final density of {approx}1.1 g/cc. An empirical fit to the density vs. bulk modulus data is K = 492769{rho}{sup 4.6548}, where K is the bulk modulus in psi, and {rho} is the material density in g/cm{sup 3}. The porosity decreased from 88% to {approx}20% indicating that much higher pressures would be required to compact the material fully.

Broome, Scott Thomas; Bauer, Stephen J.

2010-09-01

34

Control of superplastic cavitation by hydrostatic pressure  

SciTech Connect

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.

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

1983-08-01

35

Comparisons of Experimental and Theoretical Dynamic Rotor-Bearing Behavior Using Gas Lubrication.  

National Technical Information Service (NTIS)

The report presents the results of an investigation into the adequacy of presently available theory in predicting the dynamic behavior of a rotor supported in hydrostatic and hydrodynamic gas lubricated journal bearings. Measurements of critical speeds, t...

R. D. Dayton

1971-01-01

36

Polar Bear  

NSDL National Science Digital Library

This site from the World Wildlife Fund (WWF) International provides general information about polar bears as well as data on the movements of two radio-collared bears, along with the ice status, through a series of online maps.

2007-01-01

37

THRUST BEARING  

DOEpatents

A thrust bearing suitable for use with a rotor or blower that is to rotate about a vertical axis is descrihed. A centrifagal jack is provided so thnt the device may opernte on one hearing at starting and lower speeds, and transfer the load to another bearing at higher speeds. A low viscosity fluid is used to lubricate the higher speed operation bearing, in connection with broad hearing -surfaces, the ability to withstand great loads, and a relatively high friction loss, as contraated to the lower speed operatio;n bearing which will withstand only light thrust loads but is sufficiently frictionfree to avoid bearing seizure during slow speed or startup operation. An axially aligned shaft pin provides the bearing surface for low rotational speeds, but at higher speed, weights operating against spring tension withdraw nthe shaft pin into the bearing proper and the rotor shaft comes in contact with the large bearing surfaces.

Heller, P.R.

1958-09-16

38

Elastic Bearing.  

National Technical Information Service (NTIS)

The common ball bearings and sliding bearings are well known to people since they are widely employed in modern industries such as trains, automobiles, ships, aircraft, machine tools, instruments, etc. They have also been used in many household appliances...

1985-01-01

39

A computationally efficient finite volume hydrostatic/non-hydrostatic hybrid model with a vertical Lagrangian coordinate  

NASA Astrophysics Data System (ADS)

Resolving interactions between clouds and aerosols in the atmosphere, which have both direct and indirect effects on climate change, requires accurate and stable numerical discretization of the equations for the non-hydrostatic atmosphere. On the other hand, the use of the hydrostatic approximation allows one to achieve high computational efficiency in simulations of large scale atmospheric motions. Here we demonstrate a computational approach for the representation of small scale motions within a GCM by utilizing adaptive grid techniques that work to couple hydrostatic and non-hydrostatic flows for future climate model predictions. We have developed consistent equations for treating the change in physics associated with smooth solutions across the interface between hydrostatic and non-hydrostatic regions. We demonstrate the use of our grid adaptation technique (the ABLCarT library) over a portion of the global grid to test its capability to treat efficiently and accurately horizontal and vertical advection. We use a test suite to examine the behavior of the adaptive coupled hydrostatic-nonhydrostatic model using 2D and 3D configurations.

Chen, X.; Andronova, N. G.; Penner, J. E.; Stout, Q. F.; Vandenberg, D.

2011-12-01

40

Develop a Fan Drive Hydro-Static Transmission.  

National Technical Information Service (NTIS)

This report details the development and endurance testing of a hydrostatic transmission consisting of a temperature controlled pressure compensated pump and a fixed-stroke inline piston hydraulic motor. The hydrostatic transmission was developed for appli...

W. F. Wesmann

1974-01-01

41

Computation and measurement of flow rate and load capacities for graphite-fed externally pressurized gas bearings. Interim report  

Microsoft Academic Search

High-precision, gas-lubricated bearings for machine tools have been developed. In a few instances, undesirable instabilities develop in the bearings. To study these instabilities, a model for the transient behavior of the lubricating gas in a hydrostatic gas bearing with porous distribution matrix has been described and solved. The model is based on Darcy's law in the matrix and Reynolds' lubrication

J. E. Park; G. E. Jr. Giles; W. H. Rasnick; P. J. Steger

1978-01-01

42

Journal bearing  

DOEpatents

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.

Menke, John R. (New York, NY); Boeker, Gilbert F. (New York, NY)

1976-05-11

43

Hydrostatic Water Level Systems At Homestake DUSEL  

Microsoft Academic Search

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

L. D. Stetler; J. T. Volk

2009-01-01

44

Railcar waste transfer system hydrostatic test report.  

National Technical Information Service (NTIS)

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, 'Railcar Waste Transfer System Hydrostatic Test'. The test was completed and approved wi...

S. D. Ellingson

1997-01-01

45

Railcar waste transfer system hydrostatic test  

SciTech Connect

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.

Ellingson, S.D.

1997-03-31

46

Railcar waste transfer system hydrostatic test report  

SciTech Connect

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.

Ellingson, S.D.

1997-04-03

47

Biomolecular electron transfer under high hydrostatic pressure  

Microsoft Academic Search

The dependence of the photoinduced electron transfer rate on hydrostatic pressure up to 8 kbar was studied at 295 K in a bridged Zn-porphyrin donor and pyromellitimide acceptor supermolecule dissolved in toluene. A picosecond fluorescence emission kinetics of the donor, limited by the electron transfer rate, was detected by using synchroscan streak camera. The experiment was complemented with model calculations

Märt Tars; Aleksandr Ellervee; Michael R. Wasielewski; Arvi Freiberg

1998-01-01

48

Maslov's method for stationary hydrostatic mountain waves  

Microsoft Academic Search

SUMMARY The ray solution for stationary hydrostatic mountain waves has a singularity along the vertical axis directly over the mountain. We use Maslov' s method to improve the ray prediction. The ray solution is determined in the wave-number domain and is then mapped by inverse Fourier transform to give a spatial description of the wave é eld that approximates the

Dave Broutman; James W. Rottman; Stephen D. Eckermann

2002-01-01

49

A Load Cell for Hydrostatic Weighing  

ERIC Educational Resources Information Center

|Although a load cell is more expensive than the autopsy scale for hydrostatic weighing, it is more accurate, easier to read, has no moving parts, is less susceptible to rust, and is less likely to be damaged by large subjects exceeding its capacity. (Author)|

Fahey, Thomas D.; Schroeder, Richard

1978-01-01

50

GAS BEARING  

DOEpatents

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.

Skarstrom, C.W.

1960-09-01

51

Is the pharynx a muscular hydrostat?  

PubMed

Failure to maintain the patency of the pharyngeal airway during sleep is central to the pathogenesis of obstructive sleep apnoea (OSA). This failure is hypothesised to be due to the combination of a small pharyngeal airway and inadequate state-dependent neuro-mechanical control. Little is known of how the pharyngeal muscles function in an integrated function to alter the size and shape of the pharyngeal airway. We hypothesise that the muscles of the pharynx function as a muscular hydrostat. Muscular hydrostats are organs that are composed almost entirely of muscle, with a complex muscular arrangement within the organ. Examples of muscular hydrostats include the mammalian tongue, octopus tentacles, elephant trunks and the medicinal leech. During muscle contraction the organ will maintain a constant volume as muscle tissue is mostly water and hence incompressible. The mechanical effect of contraction of individual muscles within the muscular hydrostat is dependent on the integrated activity of all other muscles, as muscle orientation is dependent on the organ shape. Functionally the significance of the muscular hydrostat model lies in the concept that alterations in organ shape are achieved via muscle contraction driven redistribution of hydrostatic tissue pressure. The tissues which comprise the pharynx are predominantly muscle, and thus incompressible. The pharynx is composed of 20 muscles that are arranged in a complex fashion. Within the peri-pharyngeal tissues the only bony structure is the hyoid bone and in adult humans this is a free-floating bone. Evidence already exists that the functional outcome of contraction of some of the pharyngeal muscles is dependent on stage of respiration, the intra-luminal pressure, or the position of the hyoid bone when the muscle is activated. There is also evidence that muscle contraction can alter the pressure in the tissues surrounding the pharynx in a non-uniform fashion. However, it has not been demonstrated for the pharynx that pharyngeal luminal shape is determined by muscle contraction determined transmural pressure distribution. The consequences of this hypothesis are that reported pharyngeal anatomical abnormalities in subjects with OSA, such as increased peri-pharyngeal fat deposition or thickening of the lateral pharyngeal walls, could result in alteration in integrated muscular function and thus a failure to maintain upper airway patency. In addition, nocturnal pharyngeal airway obstruction may result from a failure of cross muscle activation. This novel paradigm may lead to greater insights into the pathogenesis of OSA as well as opening new avenues for exploration of novel therapeutic strategies. PMID:20056338

Kairaitis, Kristina

2010-01-06

52

Seismic bearing  

Microsoft Academic Search

Textron Systems (Textron) has been using geophones for target detection for many years. This sensing capability was utilized for detection and classification purposes only. Recently Textron has been evaluating multiaxis geophones to calculate bearings and track targets more specifically personnel. This capability will not only aid the system in locating personnel in bearing space or cartesian space but also enhance

Dennis Power

2009-01-01

53

Polar Bear  

USGS Publications Warehouse

Polar bears are long-lived, late-maturing carnivores that have relatively low rates of reproduction and natural mortality. Their populations are susceptible to disturbance from human activities, such as the exploration and development of mineral resources or hunting. Polar bear populations have been an important renewable resource available to coastal communities throughout the Arctic for thousands of years.

Amstrup, S. D.; DeMaster

1988-01-01

54

A Multipurpose Device for Some Hydrostatics Questions  

ERIC Educational Resources Information Center

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

Ganci, Salvatore

2008-01-01

55

Dynamic Whirl in Well-Aligned, Liquid-Lubricated End-Face Seals with Hydrostatic Tilt Instability  

Microsoft Academic Search

Dynamic whirl in well-aligned, fully liquid-lubricated end-face seals is analyzed and tested. As with whirl of journal bearings, seal whirl occurs under lightly loaded conditions, in this case controlled by balance ratio.The two common seal arrangements are analyzed, including effects of the elastomer secondary sealing elements. Whirling is found to be induced by hydrostatic tilt instability and controlled hydrodynamically. Elastomer

R. Metcalfe

1982-01-01

56

Dynamic whirl in well-aligned, liquid-lubricated end-face seals with hydrostatic tilt instability  

Microsoft Academic Search

Dynamic whirl in well-aligned, fully liquid-lubricated end-face seals is analyzed and tested. As with whirl of journal bearings, seal whirl occurs under lightly loaded conditions, in this case controlled by balance ratio. The two common seal arrangements are analyzed, including effects of the elastomer secondary sealing elements. Whirling is found to be induced by hydrostatic tilt instability and controlled hydrodynamically.

Metcalfe

1980-01-01

57

Effect of hydrostatic extrusion on mechanical properties of trip steels  

Microsoft Academic Search

1.Hydrostatic extrusion increases the deformability of TRIP steels, which simplifies the treatment but retains the good combination of mechanical properties.2.Good mechanical properties of TRIP steels are obtained by warm hydrostatic extrusion (250°), ensuring large reductions (75%): s0.2=180 kg\\/mm2, sb=200 kg\\/mm2, d=10%. Hydrostatic extrusion at room temperature permits reductions of only 44%, which leads to lower strength characteristics —s0.2=150 kg\\/mm2, sb=174

B. I. Beresnev; I. Ya. Georgieva; V. G. Kozlov; G. A. Pigushina; V. P. Chernyshov

1976-01-01

58

Hydrostatic piezoelectric effect in lead titanate ceramics  

SciTech Connect

The hydrostatic piezoelectric characteristics of Pb{sub 0.955-x}Sm{sub 2x/3}Bi{sub 0.03}Ti{sub 0.98}Mn{sub 0.02}O{sub 3} ceramics were studied. Within the range of at least 25 to 70 degrees C and at high hydrostaic and uniaxial pressures of 0.1-60 MPa, a high stability of the no-load piezoelectric voltage coefficient for the material with x=0.09-0.15 was found.

Lopatin, S.S.; Lupeiko, T.G.; Zvyagintsev, B.I. [Rostov State Univ. (Russian Federation)] [and others

1994-10-01

59

Hydrostatic compression in glycerinated rabbit muscle fibers.  

PubMed Central

Glycerinated muscle fibers isolated from rabbit psoas muscle, and a number of other nonmuscle elastic fibers including glass, rubber, and collagen, were exposed to hydrostatic pressures of up to 10 MPa (100 Atm) to determine the pressure sensitivity of their isometric tension. The isometric tension of muscle fibers in the relaxed state (passive tension) was insensitive to increased pressure, whereas the muscle fiber tension in rigor state increased linearly with pressure. The tension of all other fiber types (except rubber) also increased with pressure; the rubber tension was pressure insensitive. The pressure sensitivity of rigor tension was 2.3 kN/m2/MPa and, in comparison with force/extension relation determined at atmospheric pressure, the hydrostatic compression in rigor muscle fibers was estimated to be 0.03% Lo/MPa. As reported previously, the active muscle fiber tension is depressed by increased pressure. The possible underlying basis of the different pressure-dependent tension behavior in relaxed, rigor, and active muscle is discussed.

Ranatunga, K W; Fortune, N S; Geeves, M A

1990-01-01

60

Acoustic cymbal performance under hydrostatic pressure  

NASA Astrophysics Data System (ADS)

Continual awareness about the need to develop light-weight, low-volume, broadband, underwater acoustic projector and receive arrays that perform consistently in diverse environments is evident in recent Navy acoustic system initiatives. Acoustic cymbals, so named for resemblance to the percussive musical instruments, are miniature flextensional transducers that may perhaps meet the performance criteria for consistent performance under hydrostatic pressure after modifications in the design. These acoustic cymbals consist of a piezoceramic disk (or ring) bonded to two opposing cymbal-shaped metal shells. Operating as mechanical transformers, the two metal shells convert the large generative force inherently within the disk's radial mode into increased volume displacement at the metal shell surface to obtain volume displacement that translates into usable source levels and/or sensitivities at sonar frequencies in a relatively broad band. The air-backed design for standard acoustic cymbal transducers presents a barrier to deepwater applications. A new acoustic cymbal design for high-pressure applications will be presented for the first time. This practical pressure compensation is designed to diminish the effects of hydrostatic pressure to maintain consistent acoustic cymbal performance. Transmit and receive performance data, determined at the Naval Undersea Warfare Center's (NUWC) Acoustic Pressure Tank Facility (APTF), is presented.

Jenne, Kirk E.; Huang, Dehua; Howarth, Thomas R.

2001-05-01

61

Hydrostatic pressure mimics gravitational pressure in characean cells  

Microsoft Academic Search

Summary Hydrostatic pressure applied to one end of a horizontalChara 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

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

1992-01-01

62

An innovative reverse osmosis desalination system using hydrostatic pressure  

Microsoft Academic Search

A description and energy efficiency analysis is presented for an innovative reverse osmosis (RO) desalination system utilizing hydrostatic pressure. Hydrostatic pressure of a water column of sufficient height to create the required pressure to drive the RO desalination system is used. The system consists of a storage tank, connecting pipes, RO module with a moving hollow piston, filter boxes, seawater

S. Al-Kharabsheh

2006-01-01

63

Factors influencing the system efficiency of hydrostatic transmission hybrid vehicles  

Microsoft Academic Search

Series hydrostatic transmission hybrid vehicle (SHHV) is an application of hydrostatic transmission technology to improve vehicle fuel economy and emissions. To make good use of the on-board energy sources in the SHHV design and application, several influencing factors on the SnHHV system efficiency are studied and evaluated. Then, the improved measures are proposed to enhance the efficiency of SHHV. Simulation

Sun Hui; Jiang Ji-hai; Wang Xin

2008-01-01

64

Secular love numbers and hydrostatic equilibrium of planets  

Microsoft Academic Search

The secular Love numbers of planets and of the Moon have been computed by use of the recent satellite data. It has been demonstrated that Venus, Mercury, and the Moon are far from the ideal hydrostatic equilibrium; the angular velocities (rotation periods) which correspond to the hydrostatic equilibrium have been computed.

M. Bursa

1984-01-01

65

Bear Bones  

NSDL National Science Digital Library

An estimated ten million Americans have osteoporosis, an age-related disease in which the bones gradually become brittle and weak. Now, scientists are looking to animals for clues on how to combat this condition. This resource describes the study of sustaining bone strength of hibernating bears.

Science Update;

2004-03-08

66

Journal Bearings.  

National Technical Information Service (NTIS)

The instability of zero or lightly loaded shafts when they rotate at high speeds in bearings in low viscosity lubricants is considered . This instability refers to a selfexcited fractional frequency whirl or tendency of the shaft center to orbit the beari...

F. T. Schuller W. A. Moore

1973-01-01

67

Gravity, the hydrostatic indifference concept and the cardiovascular system.  

PubMed

Gravity, like any acceleration, causes a hydrostatic pressure gradient in fluid-filled bodily compartments. At a force of 1G, this pressure gradient amounts to 10 kPa/m. Postural changes alter the distribution of hydrostatic pressure patterns according to the body's alignment to the acceleration field. At a certain location--referred to as hydrostatically indifferent--within any given fluid compartment, pressure remains constant during a given change of position relative to the acceleration force acting upon the body. At this specific location, there is probably little change in vessel volume, wall tension, and the balance of Starling forces after a positional manoeuvre. In terms of cardiac function, this is important because arterial and venous hydrostatic indifference locations determine postural cardiac preload and afterload changes. Baroreceptors pick up pressure signals that depend on their respective distance to hydrostatic indifference locations with any change of body position. Vascular shape, filling volume, and compliance, as well as temperature, nervous and endocrine factors, drugs, and time all influence hydrostatic indifference locations. This paper reviews the physiology of pressure gradients in the cardiovascular system that are operational in a gravitational/acceleration field, offers a broadened hydrostatic indifference concept, and discusses implications that are relevant in physiological and clinical terms. PMID:20857139

Hinghofer-Szalkay, Helmut

2010-09-21

68

Gravity, the hydrostatic indifference concept and the cardiovascular system  

Microsoft Academic Search

Gravity, like any acceleration, causes a hydrostatic pressure gradient in fluid-filled bodily compartments. At a force of\\u000a 1G, this pressure gradient amounts to 10 kPa\\/m. Postural changes alter the distribution of hydrostatic pressure patterns according\\u000a to the body’s alignment to the acceleration field. At a certain location—referred to as hydrostatically indifferent—within\\u000a any given fluid compartment, pressure remains constant during a given

Helmut Hinghofer-Szalkay

2011-01-01

69

Fluid Lubricated Bearing Construction.  

National Technical Information Service (NTIS)

A fluid lubricated thrust bearing assembly is described. A first bearing member has a plain bearing surface; a second bearing member has a bearing surface confronting the surface of the first bearing and is provided with at least one spiral groove extendi...

J. R. Dunning H. A. Boorse G. F. Boeker

1976-01-01

70

Obliquity and non-hydrostaticity: Constraining the interior of Titan  

NASA Astrophysics Data System (ADS)

The orientation of the rotation axis of Titan has been measured on the basis of Cassini radar images [5, 6]. It has been shown that this orientation is more consistent with the presence of an internal global liquid ocean beneath an ice shell than with an entirely solid Titan [1]. The global topography data seem to indicate some departure from the hydrostatic shape expected for a synchronous satellite under the influence of its rotation and the static tides raised by the central planet, although the possibility of Titan being in hydrostatic equilibrium cannot be ruled out [7]. We investigate how the non-hydrostaticity may influence the obliquity solution. Then, we derive interior models which are compatible with the observed orientation as well as gravity and a non-hydrostatic shape deduced from the solution of [7].

Baland, R.-M.; Tobie, G.; Lefèvre, A.

2012-09-01

71

Computational Model of Hydrostatically Coupled Dielectric Elastomer Actuators (Preprint).  

National Technical Information Service (NTIS)

A hydrostatically coupled dielectric elastomer (HCDE) actuator consists of two membranes of a dielectric elastomer, clamped with rigid circular rings. Confined between the membranes is a fixed volume of a fluid, which couples the movements of the two memb...

F. Carpi H. Wang S. Cai Z. Suo

2011-01-01

72

Elastic Properties and Internal Friction of Hydrostatically Extruded Molybdenum.  

National Technical Information Service (NTIS)

The work examines the effect of cold plastic deformation on the Young's modulus, shear modulus, Poisson ratio, and internal friction of the polycrystalline molybdenum of various composition during the hydrostatic extrusion. (Author)

A. I. Evstyukhin G. A. Mochalov O. N. Sidorenko V. V. Sevryugin

1972-01-01

73

Characterization and measurement of hybrid gas journal bearings  

NASA Astrophysics Data System (ADS)

This thesis concentrates on the study of hybrid gas journal bearings (bearings with externally pressurized mass addition). It differs from most work in that it goes back to "basics" to explore the hydrodynamic phenomena in the bearing gap. The thesis compares geometrically identical bearings with 2 configurations of external pressurization, porous liners where mass-addition compensation is varied by varying the liner's permeability, and bushings with 2 rows of 6 feedholes where the mass-addition compensation is varied by the feedhole diameter. Experimentally, prototype bearings with mass-addition compensation that spans 2 orders of magnitude with differing clearances are built and their aerostatic properties and mass addition characteristics are thoroughly tested. The fundamental equations for compressible, laminar, Poiseuille flow are used to suggest how the mass flow "compensation" should be mathematically modeled. This is back-checked against the experimental mass flow measurements and is used to determine a mass-addition compensation parameter (called Kmeas) for each prototype bushing. In so doing, the methodology of modeling and measuring the mass addition in a hybrid gas bearing is re-examined and an innovative, practical, and simple method is found that makes it possible to make an "apples-to-apples" comparison between different configurations of external pressurization. This mass addition model is used in conjunction with the Reynolds equation to perform theory-based numerical analysis of virtual hybrid gas journal bearings (CFD experiments). The first CFD experiments performed use virtual bearings modeled to be identical to the experimental prototypes and replicate the experimental work. The results are compared and the CFD model is validated. The ontological significance of appropriate dimensionless similitude parameters is re-examined and a, previously lacking, complete set of similitude factors is found for hybrid bearings. A new practical method is 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 relate

Lawrence, Tom Marquis

74

Mechanical stability of iron under hydrostatic stresses  

NASA Astrophysics Data System (ADS)

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

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

1991-09-01

75

Experimental determination of the rotor dynamic coefficients of a gas-lubricated foil journal bearing  

Microsoft Academic Search

This thesis describes an experimental investigation of the dynamic stiffness and damping characteristics of an air lubricated leaf-type foil journal bearing. A test bed with dynamic force and response measurement capabilities has been designed and fabricated as a part of the research effort. The test bed consists of a two inch diameter rotor which is supported on two hydrostatic air

Keith Alan Hurley

1998-01-01

76

Fluid lubricated bearing construction  

DOEpatents

1. A fluid lubricated thrust bearing assembly comprising, in combination, a first bearing member having a plain bearing surface, a second bearing member having a bearing surface confronting the bearing surface of said first bearing member and provided with at least one spiral groove extending inwardly from the periphery of said second bearing member, one of said bearing members having an axial fluid-tight well, a source of fluid lubricant adjacent to the periphery of said second bearing member, and means for relatively rotating said bearing members to cause said lubricant to be drawn through said groove and to flow between said bearing surfaces, whereby a sufficient pressure is built up between said bearing surfaces and in said well to tend to separate said bearing surfaces.

Dunning, John R. (Riverdale, NY); Boorse, Henry A. (Leonia, NJ); Boeker, Gilbert F. (New York, NY)

1976-01-01

77

Gas Lubrication Research for 1900 F Non-Isothermal Operation. Part I. Bearing Distortion Effects on Performance, and High Temperature Material Investigations.  

National Technical Information Service (NTIS)

The objective of this program is to develop hydrodynamic and hydrostatic gas lubricated journal and thrust bearings that offer the most promise for non-isothermal operation in air over the ranges: 0 to 90,000 RPM at 80 F to 1400 F Bearing Temperature and ...

D. Wilson F. Murray

1967-01-01

78

An In-Vitro Traumatic Model To Evaluate the Response of Myelinated Cultures to Sustained Hydrostatic Compression Injury  

PubMed Central

Abstract While a variety of in-vitro models have been employed to investigate the response of load-bearing tissues to hydrostatic pressure, long-term studies are limited by the need to provide for adequate gas exchange during pressurization. Applying compression in vitro may alter the equilibrium of the system and thereby disrupt the gas exchange kinetics. To address this, several sophisticated compression chamber designs have been developed. However, these systems are limited in the magnitude of pressure that can be applied and may require frequent media changes, thereby eliminating critical autocrine and paracrine signaling factors. To better isolate the cellular response to long-term compression, we created a model that features continuous gas flow through the chamber during pressurization, and a negative feedback control system to rigorously control dissolved oxygen levels. Monitoring dissolved oxygen continuously during pressurization, we find that the ensuing response exhibits characteristics of a second- or higher-order system which can be mathematically modeled using a second-order differential equation. Finally, we use the system to model chronic nerve compression injuries, such as carpal tunnel syndrome and spinal nerve root stenosis, with myelinated neuron-Schwann cell co-cultures. Cell membrane integrity assay results show that co-cultures respond differently to hydrostatic pressure, depending on the magnitude and duration of stimulation. In addition, we find that myelinated Schwann cells proliferate in response to applied hydrostatic compression.

Frieboes, Laura R.

2009-01-01

79

Be Star Disk Models in Consistent Vertical Hydrostatic Equilibrium  

NASA Astrophysics Data System (ADS)

A popular model for the circumstellar disks of Be stars is that of a geometrically thin disk with a density in the equatorial plane that drops as a power law of distance from the star. It is usually assumed that the vertical structure of such a disk (in the direction parallel to the stellar rotation axis) is governed by the hydrostatic equilibrium set by the vertical component of the star's gravitational acceleration. Previous radiative equilibrium models for such disks have usually been computed assuming a fixed density structure. This introduces an inconsistency as the gas density is not allowed to respond to temperature changes and the resultant disk model is not in vertical, hydrostatic equilibrium. In this work, we modify the BEDISK code of Sigut & Jones so that it enforces a hydrostatic equilibrium consistent with the temperature solution. We compare the disk densities, temperatures, H? line profiles, and near-IR excesses predicted by such models with those computed from models with a fixed density structure. We find that the fixed models can differ substantially from the consistent hydrostatic models when the disk density is high enough that the circumstellar disk develops a cool (T lsim 10, 000 K) equatorial region close to the parent star. Based on these new hydrostatic disks, we also predict an approximate relation between the (global) density-averaged disk temperature and the T eff of the central star, covering the full range of central Be star spectral types.

Sigut, T. A. A.; McGill, M. A.; Jones, C. E.

2009-07-01

80

Hydrostatic Microextrusion of Steel and Copper  

SciTech Connect

The paper presents an experimental investigation based on hydrostatic micro extrusion of billets in low carbon steel and commercially pure copper, and the relevant results. The starting billets have a diameter of 0.3 mm and are 5 mm long; a high pressure generator consisting of a manually operated piston screw pump is used to pressurize the fluid up to 4200 bar, the screw pump is connected through a 3-way distribution block to the extrusion die and to a strain gauge high pressure sensor. The sensor has a full scale of 5000 bar and the extrusion pressure is acquired at a sampling rate of 2 kHz by means of an acquisition program written in the LabVIEW environment. Tests have been conducted at room temperature and a lubricant for wire drawing (Chemetall Gardolube DO 338) acts both as the pressurizing fluid and lubricant too. In addition, billets were graphite coated. Different fluid pressures and process durations have been adopted, resulting in different extrusion lengths. The required extrusion pressure is much higher than in non-micro forming operations (this effect is more evident for steel). On the cross section of the extruded parts, hardness and grain size distribution have been measured, the former through Vickers micro hardness (10 g load) tests. In the case of the extrusion of copper, the material behaves as in microdrawing process. In the case of the extrusion of steel, the hardness increases from the core to the surface as in the drawing process, but with lower values. The analysis evidenced the presence of the external layer, but its thickness is about 1/3 of the external layer in the drawn wire and the grains appear smaller than in the layer of the drawn wire. The extruding force required along the extruding direction is higher (22-24 N) than the drawing force along the same direction (12 N): being the material, the reduction ratio, the die sliding length the same in both cases, the higher extrusion force should be caused by a higher tangential friction force and/or a higher redundant work of deformation and/or a different material behaviour. Which is the real mechanism is not clear at present, but surface layer grains in extrusion are more deformed than in wire drawing. For this reason the deformation inhomogeneity increases in extrusion and the material under the highly deformed surface layer should be subjected to lower strains, strain hardening and finally resulting in lower hardness.

Berti, Guido; Monti, Manuel [University of Padua, DTG, Stradella San Nicola 3, I-36100 Vicenza (Italy); D'Angelo, Luciano [University of Ferrara, Dept. of Engineering, via Saragat 3, 44100 Ferrara (Italy)

2011-05-04

81

Investigating Science through Bears (and Teddy Bears).  

ERIC Educational Resources Information Center

Presents cooperative classroom projects using science as the initial basis for the study of bears. These projects may also involve other areas of the curriculum such as mathematics, art, and music. "Black Bear" activities include following a park ranger to study our National Parks and researching and building a full-sized brown bear habitat. (AIM)

Smith, Karlene Ray

1997-01-01

82

Investigating Science through Bears (and Teddy Bears).  

ERIC Educational Resources Information Center

|Presents cooperative classroom projects using science as the initial basis for the study of bears. These projects may also involve other areas of the curriculum such as mathematics, art, and music. "Black Bear" activities include following a park ranger to study our National Parks and researching and building a full-sized brown bear habitat.…

Smith, Karlene Ray

1997-01-01

83

Hydrostatic levelling systems: Measuring at the system limits  

NASA Astrophysics Data System (ADS)

Three hydrostatic displacement monitoring system applications in Switzerland are discussed; the first concerns experience gained monitoring the foundation of the Albigna dam, the second relating to the underground stability of the Swiss Light Source synchrotron and the third concerning the deformation of a bridge near the city of Lucerne. Two different principles were applied, the Hydrostatic Levelling System (HLS) using the “half-filled pipe principle” developed by the Paul Scherrer Institute and the Large Area Settlement System (LAS) using the “differential pressure principle”. With both systems ground deformations induced by tidal forces can be seen. However, high accuracy of single sensors is not sufficient. A well-designed configuration of the complete system is equally important. On the other hand there are also limits imposed by installation logistics and by the environmental conditions. An example is the bridge monitoring application, where the acceleration along the bridge due to the passage of heavy trucks limits the feasibility of using hydrostatic levelling measurements.

Meier, Edi; Geiger, Alain; Ingensand, Hilmar; Licht, Hans; Limpach, Philippe; Steiger, Andreas; Zwyssig, Roger

2010-09-01

84

Implications of the Hydrostatic Assumption on Atmospheric Gravity Waves.  

NASA Astrophysics Data System (ADS)

The validity of the hydrostatic approximation is examined for use in predicting the dynamics of topographically generated atmospheric gravity waves (lee waves) propagating in an atmosphere with realistic wind shear. To isolate nonhydrostatic effects, linear, analytic solutions derived both with and without the hydrostatic assumption are compared. The atmospheric profiles of wind and stability are chosen both to render the governing equations analytically tractable and be representative of typical atmospheric conditions. Two atmospheric models are considered: 1) a troposphere-only model in which the wind increases linearly with height and the stability is constant and 2) a troposphere-stratosphere model, which retains the important effect of the vertical wind shear in the troposphere and adds the essential feature of a stability jump at the tropopause. The nonhydrostatic trapping effect of wind shear on gravity wave modes is clearly illustrated in the troposphere-only atmospheric model. In the troposphere-stratosphere model the vertical wind shear partially traps nonhydrostatic waves in the troposphere, which leak energy into the stratosphere; this effect is completely eliminated in the hydrostatic solution. Solutions for both hydrostatic and nonhydrostatic cases are examined for a range of tropospheric Richardson numbers and tropopause depths. Results show that the hydrostatic approximation radically alters the character of the gravity wave reflection and transmission through the tropopause, as well as both the magnitude and distribution of the momentum flux in the troposphere and stratosphere. Of particular importance is the downstream shift of momentum flux by the nonhydrostatic component, which can lead to misinterpretation of momentum flux measurements in both aircraft data and numerical models. It is found that the nonhydrostatic component is significant in this strongly sheared environment, even when the mountain is broad. Thus, even for relatively large-scale topographic forcing, the hydrostatic assumption may not be justified for gravity wave calculations.

Keller, Teddie L.

1994-07-01

85

A hydrostatic pressure approach to cuffless blood pressure monitoring.  

PubMed

This paper presents the underlying principle and accompanying initial validation results towards the development of an optically-based, cuffless blood pressure monitoring method. As opposed to traditional oscillometric techniques, the optical sensor is calibrated with a known patient-controlled hydrostatic perturbation. In particular, the hydrostatic pressure challenge is utilized to parameterize the characteristic sigmoidal vascular compliance curve that links transmural pressure to the measured PPG output. Formulation of the compliance model will be accompanied by experimental results demonstrating the utility of the method. PMID:17272155

Shaltis, P; Reisner, A; Asada, H

2004-01-01

86

Regulations Associated with the Hydrostatic Testing of Natural Gas Pipelines. Volume 2. Topical Report, May 1992.  

National Technical Information Service (NTIS)

The report examines environmental regulatory issues related to the discharge of hydrostatic test waters generated from the integrity testing of natural gas pipelines. Hydrostatic testing, and proper environmental management of discharged waters is require...

L. M. Bruderly T. A. Halapin J. P. Fillo

1992-01-01

87

Bearings for Your Whirligig  

NSDL National Science Digital Library

Experiment with friction and make bearings for a whirligig! This activity is a nice introduction to friction and bearings and demonstrates why bearings are useful for spinning. A related video show Vollis Simpson, an artist who creates kinetic sculptures and whirligigs, explain how he uses bearings in all of his spinning pieces so that they move smoothly.

Minnesota, Science M.

1995-01-01

88

Thrust bearing for turbocharger  

Microsoft Academic Search

A thrust bearing is described for sustaining the thrust load of the rotor shaft of a turbocharger, the thrust bearing having a first and second opposed side surface, comprising: A first groove formed in the first side surface of the thrust bearing for holding lubricating oil supplied to the bearing; at least one first oil passage extending from the groove

T. Tamura; N. Shibata; T. Kawakami

1987-01-01

89

The Hydrostatic Noncontact Seal Including Fluid Inertia Effect  

Microsoft Academic Search

Hydrostatic noncontact seals are becoming more widely used as shaft seals for high-pressure water pumps. This work shows that the hydrodynamic pressure head (? · u\\/2), where ? is fluid density) should not be ignored in such seals where leakage velocity, u, is high. This “inertia” effect causes a change of pressure profile on the seal surface and affects force

Tadashi Koga; Takuya Fujita

1986-01-01

90

The influence of increased tubular hydrostatic pressure on renal function.  

PubMed

The effect of tubular obstruction on renal function has been understood poorly at the tubular level and from the clinical standpoint. In our review the evidence for a direct influence of hydrostatic pressure on tubular transport and glomerular filtration is examined. The data generated to date indicate a direct influence of hydrostatic pressure on tubular transport only at the level of the distal convoluted tubule and collecting duct. With respect to glomerular filtration increased tubular pressure reduces the net driving force for filtration and reduces glomerular filtration rate in the absence of a compensatory increase in glomerular hydrostatic pressure. We next review physiological data concerning the mechanism of post-obstructive diuresis. Available information suggests 4 factors that play a significant role in the clinical syndrome of post-obstructive diuresis: 1) medullo-papillary washout, 2) decreased fractional and absolute salt and water reabsorption in the collecting duct, presumably secondary to direct influence of hydrostatic pressure on transport mechanisms, 3) osmotic diuresis secondary to retention of urea and other osmotic solutes during the period of obstruction and 4) prior salt and water administration in the absence of excretion, resulting in extracellular fluid volume expansion. PMID:772239

Gross, J B; Kokko, J P

1976-04-01

91

Deformation of a carbon-epoxy composite under hydrostatic pressure  

Microsoft Academic Search

This paper describes the behaviour of a carbon-fibre reinforced epoxy composite when deformed in compression under high hydrostatic confining pressures. The composite consisted of 36% by volume of continuous fibres of Modmur Type II embedded in Epikote 828 epoxy resin. When deformed under pressures of less than 100 MPa the composite failed by longitudinal splitting, but splitting was suppressed at

C. W. Weaver; J. G. Williams

1975-01-01

92

INACTIVATION OF SELECTED PICORNAVIRUS BY HIGH HYDROSTATIC PRESSURE  

Technology Transfer Automated Retrieval System (TEKTRAN)

The potential of high hydrostatic pressure processing (HPP) to inactivate Aichivirus, human parechovirus-1, and Coxsackievirus strains A9 and B5 was investigated. For Coxsackievirus A9, a 5-min HPP treatment in minimum essential growth medium (MEM) supplemented with 10% fetal bovine sera (FBS) resu...

93

Modeling and tracking control of a hydrostatic dynamometer  

Microsoft Academic Search

Traditionally automotive powertrain research and development have been conducted with electromagnetic dynamometers. The ever increasing demand for reducing fuel consumption and emissions has driven the innovation of new technologies in engines, transmissions, and hybrid systems, which in turn requires significant flexibilities and transient capabilities of the dynamometer. Given its superior power density, hydrostatic dynamometer is an ideal candidate for the

Yu Wang; Zongxuan Sun; Kim Stelson

2009-01-01

94

High Hydrostatic Pressure Processing of Fruit and Vegetable Products  

Microsoft Academic Search

High hydrostatic pressure (HHP) as a minimal thermal technology is a valuable tool for microbiologically safe and shelf-stable fruit and vegetable production. Microorganisms and deteriorative enzymes can be inhibited or inactivated depending on the amount of pressure and time applied to the product. The resistance of microorganisms and enzymes to pressure in fruit and vegetable products also is dependent on

José A. Guerrero-Beltrán; Gustavo V. Barbosa-Cánovas; Barry G. Swanson

2005-01-01

95

Long-Term Hydrostatic Tests of Syntactic Foam.  

National Technical Information Service (NTIS)

Syntactic foam samples were tested in fresh water under pressures of 3000, 5000, and 10,000 psi at 2C and at room temperature (about 25C). The samples were 1-3/4-in.-diam, 6-in.-long solid cylinders. The long-term hydrostatic test results, presented here,...

J. J. Gennari H. E. Barnes

1967-01-01

96

Comparison of hydrostatic and hydrodynamic pressure to inactivate foodborne viruses  

Technology Transfer Automated Retrieval System (TEKTRAN)

The effect of high hydrostatic pressure (HPP) and hydrodynamic pressure (HDP), in combination with chemical treatments, was evaluated for inactivation of foodborne viruses and non-pathogenic surrogates in a pork sausage product. Sausages were immersed in water, 100 ppm EDTA, or 2 percent lactoferrin...

97

Bioelectric Impedance and Hydrostatic Weighing With and Without Head Submersion in Persons Who are Morbidly Obese  

Microsoft Academic Search

Objective To compare hydrostatic weighing with and without head submersion and bioelectric impedance analysis (BIA) for measurement of body composition of persons who are morbidly obese.Design Body composition was determined using 3 methods: hydrostatic weighing with and without head submersion and BIA. Residual volume for the hydrostatic weighing calculation was determined by body plethysmography.Subjects Subjects were 16 morbidly obese men

EDWARD M HEATH; TED D ADAMS; MARIA MATTHEWS DAINES; STEVEN C HUNT

1998-01-01

98

Fatigue of specimens subjected to combined loading. Role of hydrostatic pressure  

Microsoft Academic Search

Tests have been carried out on smooth and notched specimens submitted to cyclic combined loading. The role of the hydrostatic pressure has been clarified using a volumetric approach. The average hydrostatic pressure and the shear stress have been computed in the fatigue process volume. An elliptical dependence between the effective shear stress and the hydrostatic pressure has been shown.

G Qilafku; N Kadi; J Dobranski; Z Azari; M Gjonaj; G Pluvinage

2001-01-01

99

Improved Hybrid Bearings.  

National Technical Information Service (NTIS)

Nitriding technology was determined to significantly enhance the performance of steel bearing rings coupled with silicon nitride balls. NBD-200 silicon nitride was tested in two different sized full scale bearing tests with two nitrided steel ring materia...

M. M. Dezzani P. K. Pearson

1994-01-01

100

High Efficiency Magnetic Bearings.  

National Technical Information Service (NTIS)

Research activities concerning high efficiency permanent magnet plus electromagnet (PM/EM) pancake magnetic bearings at the University of Maryland are reported. A description of the construction and working of the magnetic bearing is provided. Next, param...

P. A. Studer C. P. Jayaraman D. K. Anand J. A. Kirk

1993-01-01

101

Magnetic bearing update.  

National Technical Information Service (NTIS)

Stabilization of whirl instability by floppy, viscous bearing mounts is discussed and required material properties are estimated for the new tilt-whirl mode in eddy-current stabilized magnetic bearings. A relatively low Young's modules Y (approximately) 1...

T. K. Fowler

1995-01-01

102

Ab initio calculation of hydrostatic absolute deformation potential of semiconductors  

NASA Astrophysics Data System (ADS)

The hydrostatic absolute deformation potential (ADP) of the valence-band maximum state is one of the most important properties of semiconductors. Yet, it has been calculated in the past only using assumptions that have not been rigorously approved. In this letter, we present an approach to calculate the hydrostatic ADP of Si, GaAs, and ZnSe using an ab initio all-electron method and lattice harmonic expansions. We show that the calculated ADP is independent of the selection of the reference energy levels. The calculated ADPs are all positive for the three systems. However, as the p-d coupling increases in the II-VI compounds, the ADP decreases.

Li, Yong-Hua; Gong, X. G.; Wei, Su-Huai

2006-01-01

103

Hydrostatic Pressure Sensing with High Birefringence Photonic Crystal Fibers  

PubMed Central

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.

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

2010-01-01

104

Hydrostatic compression of Fe(1-x)O wuestite  

NASA Astrophysics Data System (ADS)

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.

Jeanloz, R.; Sato-Sorensen, Y.

1986-04-01

105

Magring sealed ball bearing  

NASA Astrophysics Data System (ADS)

A one piece, magnetic liquid shaft seal installed between the ball bearing races provides a hermetic dynamic seal. This paper discusses the advantages of such a sealed ball bearing and includes experimental data dealing with differential pressure capability, effect of mixing of magnetic liquid with grease on bearing noise, etc.

Hirao, A.; Ezekiel, F. D.

1987-03-01

106

High Strength Ceramics Bearings.  

National Technical Information Service (NTIS)

Rotordynamics-Seal Research is currently performing on a 6 month contract to develop high strength ceramic bearings using a new low cost process. This effort consists of development of a ceramic bearing design, fabrication, and testing of the bearing in a...

J. K. Scharrer

1997-01-01

107

Effect of Hydrostatic Pressure on Ferroelectricity of KNO3  

Microsoft Academic Search

The pressure dependences of spontaneous polarization and dielectric constant of KNO3 single crystals were measured under hydrostatic pressure up to 3,000 kg\\/cm2. At 130°C, the spontaneous polarization is almost independent of pressure, keeping up the magnitude of 10.4 muC\\/cm2. The dielectric constant in paraelectric phase, phase I, obeys the Curie-Weiss law. The Curie constant C is, however, dependent on pressure.

Michio Midorikawa; Yoshihiro Ishibashi; Yutaka Takagi

1971-01-01

108

High hydrostatic pressure technology in dairy processing: a review  

Microsoft Academic Search

Consumers demand high quality foods, which are fresh, tasty and nutritious; this has created considerable interest in the\\u000a development of new food processing techniques. Presently, non-thermal techniques, including high hydrostatic pressure (HHP),\\u000a are regarded with special interest by the food industry. Pressure ranges between 100 and 1200 MPa have been considered as\\u000a effective to inactivate microorganisms including food-borne pathogens. HHP also

Rekha Chawla; Girdhari Ramdass Patil; Ashish Kumar Singh

2011-01-01

109

High hydrostatic pressure and biology: a brief history  

Microsoft Academic Search

Pressure as a thermodynamical parameter was successively introduced in physics, hydrometallurgy, geochemistry, and biology.\\u000a In all cases, the main objective was to recreate a natural phenomenon (gas or liquid compressibility, synthesis or crystal\\u000a growth of minerals, survival of deep sea microorganisms…). The introduction of high hydrostatic pressure (HHP) in Biology\\u000a was an important scientific feature over the last hundred years.

Gérard Demazeau; Nolwennig Rivalain

2011-01-01

110

Non-hydrostatic effects in layered shallow water flows  

Microsoft Academic Search

This paper develops a one-dimensional extension to classical layered hydraulics that incorporates non-hydrostatic effects. General results for a homogeneous layer in a multi-layer steady flow are applied to single- and two-layer flow over a two-dimensional sill. The equation obtained for single-layer flows is the same as that obtained by Naghdi & Vongsarnpigoon (1986) using the direct theory of constrained fluid

David Z. Zhu; Gregory A. Lawrence

1998-01-01

111

Hydrostatic rectosigmoid perforation: a rare personal watercraft injury.  

PubMed

Personal watercrafts (PWC), also known as jet skis, seadoos, and wave-runners have risen in popularity since their introduction in the 1970s. Hydrostatic rectal injury is a rare presentation of passengers thrown off a PWC. The perforation of the rectum is owing to the excessive hydrostatic force of water exerted through the anal canal. We present the first case of rectosigmoid perforation secondary to PWC hydrostatic injury in Canada. A 14-year-old female passenger presented to the pediatric trauma center with severe abdominal pain and blood per rectum following a fall off the back of a PWC at a local lake. Computed tomography of the abdomen and pelvis demonstrated a laceration in the anterolateral rectal wall at the rectosigmoid junction with associated free intra-peritoneal air and profuse free fluid. At exploratory laparotomy, a full thickness perforation was identified at the rectosigmoid junction. The rectum was oversewn as a Hartman pouch, and a proximal end colostomy was performed to divert the fecal stream. Management of traumatic pediatric rectal injuries involves detailed perineal examination with proctoscopy, and if warranted, exploratory laparotomy. Despite the rare occurrence of hydrostatic rectal perforations in Canada, it is a serious and potentially devastating injury. In the United States, the National Transportation Safety Board recommends wet suit bottoms for all pediatric PWC operators and passengers. In Canada, similar recommendations have not been made. The use of PWC in Canada is less common than in the US. However, it is steadily increasing, especially on local lakes. Education regarding potential injuries and prevention is recommended. PMID:21292097

Gill, Richdeep S; Mangat, Harshdeep; Al-Adra, David P; Evans, Mark

2011-02-01

112

Cuffless blood pressure monitoring using hydrostatic pressure changes.  

PubMed

This paper presents a new principle for noninvasive blood pressure measurements through a modified volume-oscillometric technique that eliminates an inflatable pressure cuff, and instead takes advantage of natural hydrostatic pressure changes caused by raising and lowering the subject's arm. This new methodology provides the distinct advantage of using an absolute gauge pressure reference for measurements, and does not necessarily require additional actuation. PMID:18714843

Shaltis, Phillip A; Reisner, Andrew T; Asada, H Harry

2008-06-01

113

Hydrostatic stress dependent yield of 7075-T6 aluminum  

SciTech Connect

Tension and compression tests on notched cylindrical bars made of 7075-T6 aluminum have been conducted as a part of an investigation of the mechanics of ductile fracture. The compression tests showed significantly stiffer behavior in the nonlinear portion of the experiment than those found from the tension tests. This difference was accounted for by incorporating a hydrostatic stress dependent yield model in the analysis of the experiment. The model was verified by comparing finite element calculations with the actual experimental results.

Benzley, S.E.; Priddy, T.G.; Soo Hoo, M.S.

1980-03-01

114

Properties of enhanced hydrostatic pressure-annealed silicon oxynitride films  

Microsoft Academic Search

The silicon oxynitride films were deposited by the plasma enhanced chemical vapor deposition (PECVD) technique at low temperature using ammonia, nitrous oxide and silane as precursor gases. The films were subjected to pre-annealing in oxygen at 1100-1200degC for 5 hr. The samples were then annealed\\/treated at 1100degC under enhanced hydrostatic pressure (HP) up to 1.17 GPa in argon. Effect of

C. K. Wong; C. W. Kok; A. Misiuk; A. Panas

2008-01-01

115

Enhancing hydrostatic gear efficiency through nonlinear optimal control strategies  

Microsoft Academic Search

Energy efficiency is a common control goal for many applications, especially in vehicles or ships. This goal stands usually in contradiction with another common goal, fast response. In the case of hydrostatic gears, two basic system configurations are used, which allow better efficiency-the primary control setup-or faster responses-the secondary control. In this paper, (1) a different control setup is proposed,

L. del Re; A. Goransson; A. Astolfi

1994-01-01

116

Full-bore well tester with hydrostatic bias  

SciTech Connect

In accordance with an illustrative embodiment of the present invention, a pressure controlled well tester apparatus having a full-bore ball valve closure element includes valve actuator means responsive to changes in the pressure of fluids in the well annulus for moving the ball valve between its open and closed positions, and bias means responsive to the hydrostatic pressure of fluids in the well bore for assisting in moving the ball valve to its fully closed position.

McGill, H.L.

1984-04-03

117

Dynamic Performance of the Stepped Hydrostatic Circumferential Gas Seal  

Microsoft Academic Search

Theoretical analysis of dynamic tracking and leakage characteristics of a self-centering, hydrostatic, stepped gas seal is presented.The equations of motion are solved numerically, taking into account shaft speed and whirl, pressure ratio across the seal, fluid film properties and face friction effects.The analysis is limtied to low axial Reynolds numbers and negligible tangential hydrodynamic pressure buildup. Became the model neglects

A. Lipschitz

1989-01-01

118

Hydrostatic pressure sensing using a polymer optical fibre Bragg gratings  

NASA Astrophysics Data System (ADS)

The sensitivity of a fibre Bragg grating (FBG) sensor fabricated in polymer optical fibre (POF) to hydrostatic pressure was investigated for the first time. In this initial investigative work a reflected Bragg response of a FBG fabricated in multimode microstructured POF (MMmPOF) was monitored, whilst the hydrostatic pressure was increased up to 10MPa. Positive sensitivities were observed, meaning a positive wavelength shift to increasing pressure, as opposed to negative sensitivities monitored when using a FBG sensor fabricated in silica optical fibre. The FBG sensors fabricated in the MMmPOF gave fractional changes in wavelength and hence sensitivities of at least 64.05×10-6/MPa, which is some 25 times larger than the -2.50×10-6/MPa sensitivity of a FBG sensor fabricated in silica optical fibre that was measured in this work. Furthermore this work highlighted a decrease in sensitivity of the FBG sensor fabricated in the MMmPOF by some 50% by sealing the holes of the mPOF at the tip of the fibre with an adhesive. This offers the potential to tailor the response of the sensor to hydrostatic pressure.

Johnson, Ian P.; Webb, David J.; Kalli, Kyriacos

2012-01-01

119

Non-hydrostatic equilibrium of the Sun and alternative physics  

NASA Astrophysics Data System (ADS)

The proved fact that the Earth and the Moon don't stay in hydrostatic equilibrium and many other evidences bring us to conclusion that dynamics and physics of all other Solar System bodies including the Sun itself ought to be studied on non-hydrostatic basis. The only reasonable and logical alternative to that is the dynamical approach. We accepted this option and found it as a promising direction. It was found that in order to change hydrostatics by dynamical physics the outer force field of the body must be replaced by its inner volumetric force pressure. This is because the gravitational and electromagnetic forces, being inner mass forces, are volumetric in their nature. The analytical approach of that is shown in our abstract presented to GD10 of GA2009. A novel equation of state for the Sun and other stars following from the dynamical approach was obtained. The common nature of gravitational and electromagnetic energy, generated by interacted (collide and scattered) elementary particles, follows from the dynamics. New ideas related to mechanism of the Solar System creation are aroused from the approach. See more information in our works: Ferronsky V.I. and S.V. Ferronsky (2007). Dynamics of the Earth, Scientific World, Moscow; Ferronsky V.I. (2008). Non-averaged virial theorem for natural systems: http://zhurnal.ape.relarn.ru/articles/2008/066e.pdf; Ferronsky V.I., S.A. Denisik and S.V. Ferronsky (1987). Jacobi Dynamics, Riedel, Dordrecht.

Ferronsky, V.

2009-04-01

120

Hydrostatic theory and G protection using tilting aircrew seats.  

PubMed

A hydrostatic theory of blackout is generally supported in the acceleration literature, but there is disagreement as to the correct origin in the thorax for h, the hydrostatic distance to the eye. Our goal was to determine whether representative published data would preferentially support some particular origin for h. Based upon a reanalysis of published data (1) relating acceleration tolerance (T) to seat-back angle (theta), it was found that a simple hydrostatic model, with h measured from the aortic valve to the eye, yields an excellent fit. The nonlinear equation fitted was Ti = Tmin 1/cos(theta i-phi), where phi = correction to back angle. The value of phi derived from the 1975 data (1) (13.74 degrees) was the same as the independent estimate of phi for this same seat (13.06 degrees) derived from published values of h, which were measured by X-ray with h referenced to the aortic-valve and eye (2). The acceleration tolerance data for the other two seats of the 1984 study also strongly supported the model. Future studies should measure h (aortic valve-to-eye), use seat-back angles giving even spacing on a 1/h scale, and analyze data using the required nonlinear methods. PMID:3827794

Nelson, J G

1987-02-01

121

Nonlinear study of a misaligned hydrodynamic journal bearing  

SciTech Connect

Hydrodynamic/hydrostatic journal bearings have been widely used in various types of high speed rotating machinery. For space applications, the issue of using cryogenic fluids as working lubricants has steadily gained in significance. The main objective of this paper is to study the nonlinear effects in a hydrodynamic journal bearing with special attention to the effects of journal axial misalignment. The numerical model that couples the Reynolds equation with the dynamics of the rotor is solved by means of a finite difference solution technique. Fluid film pressures that resulted from an iterative scheme are integrated to generate bearing supporting forces. A two-dimensional Newton-Raphson iteration method is used to locate the journal equilibrium position from which both linear and nonlinear bearing stiffness are evaluated by means of the small perturbation technique. The effects of axial misalignment on bearing equilibrium position, lubricant fluid film thickness, pressure distribution, and stiffness characteristics are examined. General conclusions are drawn from the parametric studies in load, speed, inlet temperature, and axial misalignment. 24 refs.

Choy, F.K.; Braun, M.J.; Hu, Y. (Akron Univ., OH (United States))

1993-07-01

122

Regulations associated with the hydrostatic testing of natural gas pipelines. Volume 2. Topical report, May 1992  

Microsoft Academic Search

The report examines environmental regulatory issues related to the discharge of hydrostatic test waters generated from the integrity testing of natural gas pipelines. Hydrostatic testing, and proper environmental management of discharged waters is required by DOT regulations. However, disposal of water used to conduct a hydrostatic pipeline test is regulated on a state-by-state basis. State-specific requirements vary widely, ranging from

L. M. Bruderly; T. A. Halapin; J. P. Fillo

1992-01-01

123

Mechanical properties of hub\\/shaft joints adhesively bonded and cured under hydrostatic pressure  

Microsoft Academic Search

Adhesively bonded hub\\/shaft joints show better mechanical properties when hydrostatic pressure by using press fits is applied on the adhesive layer. This paper presents a newly developed adhesively bonded hub\\/shaft joint that allows to cure the adhesive at defined high hydrostatic pressure. After injection into a cavity of defined width between hub and shaft hydrostatic pressure of up to 120MPa

R. Mengel; J. Häberle; M. Schlimmer

2007-01-01

124

The Incredible Water Bear  

NSDL National Science Digital Library

This image-rich Micscape Magazine article explores how water bears can be found almost everywhere yet are still unknown to almost everybody, why there are relatively few light microscope photographs of water bears in the literature and on the Web, and how light microscopy can outperform scanning electron microscopy when viewing these animals. It includes a list of historical references, early sketches, and colorful images of water bears, also known as tardigrades.

Mach, Martin

2009-06-17

125

Novel bidirectional air bearing  

NASA Astrophysics Data System (ADS)

Fluid lubricated bearings (ball or journal) exhibit problems of life and contamination in high speed polygonal scanners, particularly at speeds above 15,000 rpm. Grooved air bearings are limited to relatively high manufacturing cost, vertical only attitude, unidirectional rotation, and they tend to ingest debris. A plain journal air bearing is described which is bidirectional, any attitude operation, is free of whirl instability and has low manufacturing cost.

Sherman, Randy J.

1993-12-01

126

Thrust bearing for turbocharger  

SciTech Connect

A thrust bearing is described for sustaining the thrust load of the rotor shaft of a turbocharger, the thrust bearing having a first and second opposed side surface, comprising: A first groove formed in the first side surface of the thrust bearing for holding lubricating oil supplied to the bearing; at least one first oil passage extending from the groove toward the axis of the rotor shaft; at least one second oil passage communicating with the first oil passage and having a plurality of oil holes connected thereto that extend respectively to a plurality of tapering land portions formed on the first and second side surfaces of the thrust bearing so that the axial thrust bearing clearance decreases in a direction of rotation of the shaft; a first and second leg portion defining a cut out portion formed exclusively in the lower end portion of the thrust bearing; a planar portion formed in the end surface of the thrust bearing along the first and second cut out portion and forming a portion of a closed loop; and a second groove formed between the planar portion and the surfaces on which the shaft bears wherein the oil holes are formed in proximity to a point of maximum thrust clearance of the tapering land portions.

Tamura, T.; Shibata, N.; Kawakami, T.

1987-01-27

127

Pasteurization of food by hydrostatic high pressure: chemical aspects.  

PubMed

Food pasteurized by hydrostatic high pressure have already been marketed in Japan. There is great interest in this method also in Europe and USA. Temperature and pressure are the essential parameters influencing the state of substances including foods. While the influence of temperature on food has been extensively investigated, effects of pressure, also in combination with temperature, are attracting increasing scientific attention now. Processes and reactions in food governed by Le Chatelier's principle are of special interest; they include chemical reactions of both low- and macromolecular compounds. Theoretical fundamentals and examples of pressure affected reactions are presented. PMID:7732731

Tauscher, B

1995-01-01

128

Hydrostatic and osmotic pressure study of the RNA hydration.  

PubMed

The tertiary structure of nucleic acids results from an equilibrium between electrostatic interactions of phosphates, stacking interactions of bases, hydrogen bonds between polar atoms and water molecules. Water interactions with ribonucleic acid play a key role in its structure formation, stabilization and dynamics. We used high hydrostatic pressure and osmotic pressure to analyze changes in RNA hydration. We analyzed the lead catalyzed hydrolysis of tRNAPhe from S. cerevisiae as well as hydrolytic activity of leadzyme. Pb(II) induced hydrolysis of the single phosphodiester bond in tRNAPhe is accompanied by release of 98 water molecules, while other molecule, leadzyme releases 86. PMID:22314910

Giel-Pietraszuk, Ma?gorzata; Barciszewski, Jan

2012-05-01

129

Single-molecule imaging at high hydrostatic pressure  

NASA Astrophysics Data System (ADS)

Direct microscopic fluorescence imaging of single molecules can provide a wealth of mechanistic information, but up to now, it has not been possible under high pressure conditions, due to limitations in microscope pressure cell design. We describe a pressure cell window design that makes it possible to image directly single molecules at high hydrostatic pressure. We demonstrate our design by imaging single molecules of Alexa Fluor 647 dye bound to DNA, at 120 and 210 bar, and following their fluorescence photodynamics. We further show that the failure pressure of this type of pressure cell window can be in excess of 1 kbar.

Vass, Hugh; Lucas Black, S.; Flors, Cristina; Lloyd, Diarmuid; Bruce Ward, F.; Allen, Rosalind J.

2013-04-01

130

Bearing Lubrication Apparatus.  

National Technical Information Service (NTIS)

The patent described apparatus for lubrication of anti-friction bearings which uses the oil bleeding characteristics of grease. The apparatus consists of a housing for attachment to a bearing and a grease reservoir wherein the grease is retained in a slop...

K. H. Warren

1970-01-01

131

Superconducting bearings in flywheels  

Microsoft Academic Search

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™. The Pirouette™ system is designed to provide 5 kWh of recoverable energy which is currently recoverable at a rate of 5 kW (future revisions will

T. A. Coombs; A. M. Campbell; I. Ganney; W. Lo; T. Twardowski; B. Dawson

1998-01-01

132

Grizzly Bear Recovery Plan.  

National Technical Information Service (NTIS)

The grizzly bear(Ursusarcios horribilis) was listed as threatened on July 28, 1975. The original recovery plan was approved on January 29, 1982. This is the first revision of that plan. The grizzly bear was originally distributed in various habitats throu...

1993-01-01

133

Fluid lubricated bearing assembly  

Microsoft Academic Search

1. A support for a loaded rotatable shaft comprising in combination on a housing having a fluid-tight cavity encasing an end portion of said shaft, a thrust bearing near the open end of said cavity for supporting the axial thrust of said shaft, said thrust bearing comprising a thrust plate mounted in said housing and a thrust collar mounted on

Henry A. Boorse; Gilbert F. Boeker; John R. Menke

1976-01-01

134

Fluid lubricated bearing assembly  

Microsoft Academic Search

A support for a loaded rotatable shaft is described. The device consists of: a housing having a fluid-tight cavity encasing an end portion of the shaft; a thrust bearing near the open end of the cavity for supporting the axial thrust of the shaft, the thrust bearing comprising a thrust plate mounted in the housing and a thrust collar mounted

H. A. Boorse; G. F. Boeker; J. R. Menke

1976-01-01

135

Collapse of composite tubes under uniform external hydrostatic pressure  

NASA Astrophysics Data System (ADS)

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

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

2009-08-01

136

L1448 IRS2E: A CANDIDATE FIRST HYDROSTATIC CORE  

SciTech Connect

Intermediate between the prestellar and Class 0 protostellar phases, the first core is a quasi-equilibrium hydrostatic object with a short lifetime and an extremely low luminosity. Recent magnetohydrodynamic (MHD) simulations suggest that the first core can even drive a molecular outflow before the formation of the second core (i.e., protostar). Using the Submillimeter Array and the Spitzer Space Telescope, we present high angular resolution observations toward the embedded dense core IRS2E in L1448. We find that source L1448 IRS2E is not visible in the sensitive Spitzer infrared images (at wavelengths from 3.6 to 70 {mu}m) and has weak (sub-) millimeter dust continuum emission. Consequently, this source has an extremely low bolometric luminosity (<0.1 L {sub sun}). Infrared and (sub-) millimeter observations clearly show an outflow emanating from this source; L1448 IRS2E represents thus far the lowest luminosity source known to be driving a molecular outflow. Comparisons with prestellar cores and Class 0 protostars suggest that L1448 IRS2E is more evolved than prestellar cores but less evolved than Class 0 protostars, i.e., at a stage intermediate between prestellar cores and Class 0 protostars. All these results are consistent with the theoretical predictions of the radiative/MHD simulations, making L1448 IRS2E the most promising candidate of the first hydrostatic core revealed so far.

Chen Xuepeng; Arce, Hector G. [Department of Astronomy, Yale University, Box 208101, New Haven, CT 06520-8101 (United States); Zhang Qizhou; Bourke, Tyler L. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Launhardt, Ralf; Schmalzl, Markus; Henning, Thomas [Max Planck Institute for Astronomy, Koenigstuhl 17, D-69117 Heidelberg (Germany)

2010-06-01

137

Opportunities of hydrostatically coupled dielectric elastomer actuators for haptic interfaces  

NASA Astrophysics Data System (ADS)

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

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

2011-03-01

138

DX centers in III-V semiconductors under hydrostatic pressure  

SciTech Connect

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{sub 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.

Wolk, J.A.

1992-11-01

139

OTV bearing deflection investigation  

NASA Astrophysics Data System (ADS)

The primary goal of the Bearing Deflectometer Investigation was to gain experience in the use of fiber optic displacement probe technology for bearing health monitoring in a liquid hydrogen turbo pump. The work specified in this Task Order was conducted in conjunction with Air Force Rocket Propulsion Laboratory Contract F04611-86-C-0010. APD conducted the analysis and design coordination to provide a displacement probe design compatible with the XLR-134 liquid hydrogen turbo pump assembly (TPA). Specifications and requirements of the bearing deflectometer were established working with Mechanical Technology Instruments, Inc. (MTI). The TPA design accommodated positioning of the probe to measure outer race cyclic deflections of the pump inlet bearing. The fiber optic sensor was installed as required in the TPA and sensor output was recorded during the TPA testing. Data review indicated that no bearing deflection signature could be differentiated from the inherent system noise. Alternate sensor installations were not investigated, but might yield different results.

Reimer, B. L.; Diepenbrock, R. T.; Millis, M. G.

1993-04-01

140

Experimental determination of the rotor dynamic coefficients of a gas-lubricated foil journal bearing  

NASA Astrophysics Data System (ADS)

This thesis describes an experimental investigation of the dynamic stiffness and damping characteristics of an air lubricated leaf-type foil journal bearing. A test bed with dynamic force and response measurement capabilities has been designed and fabricated as a part of the research effort. The test bed consists of a two inch diameter rotor which is supported on two hydrostatic air bearings. The test bearing is centered on the test rotor. The test bed has rotor speed capability of up to 30,000 rpm. Transverse static and dynamic loads of up to 100 lbs can be applied to the test bearing. Direct and cross-coupled transverse stiffness and damping coefficients for a two inch diameter by two inch long eight-leaf foil bearing are obtained using a frequency domain estimation algorithm. Foil bearing dynamic coefficient data is presented for a range of average bearing loads, rotor speeds, and whirl frequency ratios. Experimental predictions of dynamic coefficients for a plain rigid test bearing have been obtained for test bed validation purposes. These experimental results are shown to be in good agreement with corresponding theoretical predictions of rigid bearing dynamic coefficients obtained using a linearized perturbation analysis method. Simulated data has been used to investigate the effects of sensor calibration error and quantization error on the prediction of dynamic coefficients. The results of these investigations are also presented. A rotordynamic analysis is also presented and demonstrates how the dynamic coefficient data can be used to obtain a quantitative assessment of rotor/bearing system stability and frequency response characteristics. Dynamic response characteristics for rigid and compliant surface bearings are compared. The results substantiate the notion that foil bearings have enhanced dynamic performance characteristics in comparison to their rigid bearing counterparts.

Hurley, Keith Alan

141

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

NASA Astrophysics Data System (ADS)

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.

Sanandres, Luis

1994-12-01

142

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

Microsoft Academic Search

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 (2.3GPa) was found for a (1:1) mixture of FC84\\/87.

V A Sidorov; R A Sadykov

2005-01-01

143

Birefringence and dispersion properties of elliptical hollow core optical fiber under hydrostatic pressure  

Microsoft Academic Search

Highly birefringent elliptical hollow core optical fiber under hydrostatic pressure is analyzed in this work using finite element method. The combined effects of thermal stress generated during fabrication and external applied stress have been considered. Birefringence increases while group velocity dispersion decreases when the fiber is under hydrostatic pressure. Higher birefringence, lower material dispersion and moderate effective area can make

Ahmad Zubair; Saima Afroz Siddiqui; M. Shah Alam

2009-01-01

144

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

PubMed

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. PMID:23493787

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

2013-03-14

145

Performance Investigation of Hydrostatic Transmission System as a Function of Pump Speed and Load Torque  

NASA Astrophysics Data System (ADS)

Every hydrostatic system requires a pump and a motor as its major components. Therefore, the operating parameters of the pump and the motor in a hydrostatic system are critical to the overall performance of the system. This paper evaluates the overall efficiency of the hydrostatic system based on the operating parameters of the pump and the motor, in this particular investigation they are the pump speed and the load torque, using the expressions obtained from the simple theory of Wilson (Hydraul Pneum Power 1:136-147, 1967). Many times in actual practice, various losses occurring in the hydrostatic system are not given proper consideration while the selection and design of the pump and the motor are made. The present article investigates the effects of the different loss coefficients of the pump and the motor on the overall performance of the system that may be useful for the selection of hydrostatic system and its components.

Mandal, S. K.; Singh, A. K.; Verma, Y.; Dasgupta, K.

2012-06-01

146

Precision Bearing Grease Selection Guide.  

National Technical Information Service (NTIS)

The study was initiated to develop a precision bearing grease selection guide. As a pan of this study, forty lubricating greases used in precision bearings, including instrument bearings was evaluated in a comprehensive series of laboratory tests in order...

I. Rhee

2006-01-01

147

Magnetic bearing update  

SciTech Connect

Stabilization of whirl instability by floppy, viscous bearing mounts is discussed and required material properties are estimated for the new tilt-whirl mode in eddy-current stabilized magnetic bearings. A relatively low Young`s modules Y {approximately} 10{sup 5} and high viscosity {zeta} {approximately} 10{sup 7} are required (both in MKS units), suggesting the need for careful mounting design. New information on periodic bearings shows that, thus far, Earshaw`s Theorem cannot be defeated by periodicity, despite the author`s earlier claims.

Fowler, T.K.

1995-05-25

148

Dynamic Culturing of Cartilage Tissue: The Significance of Hydrostatic Pressure  

PubMed Central

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 amplitude-dependant manner.

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

2012-01-01

149

Dynamic culturing of cartilage tissue: the significance of hydrostatic pressure.  

PubMed

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 (10×10(6) 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 (10×10(6) 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 amplitude-dependant manner. PMID:22559784

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

2012-06-25

150

Bearings. Volume I.  

National Technical Information Service (NTIS)

This bibliography contains a selection of references to reports on bearings, cataloged by the Defense Documentation Center since 1953. The present volume, Volume I, is a compilation of 232 unclassified references with unlimited distribution. These same re...

1969-01-01

151

Optimal synchronizability of bearings.  

PubMed

Bearings are mechanical dissipative systems that, when perturbed, relax toward a synchronized (bearing) state. Here we find that bearings can be perceived as physical realizations of complex networks of oscillators with asymmetrically weighted couplings. Accordingly, these networks can exhibit optimal synchronization properties through fine-tuning of the local interaction strength as a function of node degree [Motter, Zhou, and Kurths, Phys. Rev. E 71, 016116 (2005)]. We show that, in analogy, the synchronizability of bearings can be maximized by counterbalancing the number of contacts and the inertia of their constituting rotor disks through the mass-radius relation, m~r(?), with an optimal exponent ?=?(×) which converges to unity for a large number of rotors. Under this condition, and regardless of the presence of a long-tailed distribution of disk radii composing the mechanical system, the average participation per disk is maximized and the energy dissipation rate is homogeneously distributed among elementary rotors. PMID:23432250

Araújo, N A M; Seybold, H; Baram, R M; Herrmann, H J; Andrade, J S

2013-02-07

152

Effect of Bearing Defects.  

National Technical Information Service (NTIS)

This program determined the relationship between selected raceway surface defects and performance and life of miniature ball bearing. The first phase of this two phase program developed the test plan for utilization in the second phase test and evaluation...

C. G. Beecher

1974-01-01

153

Bearing Capacity of Soils.  

National Technical Information Service (NTIS)

This manual presents guidelines for calculation of the bearing capacity of soil under shallow and deep foundations supporting various types of structures and embankments. This information is generally applicable to foundation investigation and design cond...

1992-01-01

154

Damage Characterization in Copper Deformed under Hydrostatic Stress - Experimental Analysis  

SciTech Connect

The results of an experimental investigation designed to determine the effect of damage created by hydrostatic tensile loading on the properties of copper are reported. Three metallurgical conditions of half-hard OFHC copper were investigated; as worked; annealed 2hr at 400 deg. C ({approx}40 micron grain diameter); and annealed 2hr at 800 deg. C ({approx}80 micron grain diameter). Mechanical property characterization included uniaxial compression tests. High rate plasticity and damage was introduced by Taylor and rod-on-rod impact tests. The damage from the high rate experiments was characterized using optical and scanning electron microscopy. Quasi-static compression specimens machined from recovered high rate samples were tested to determine the influence of damage on the mechanical response of the material. The compression test results will be discussed in relationship to the starting microstructure and the extent of damaged introduced into the material.

Flater, P. J.; House, J. W.; Nixon, M. E. [Air Force Research Laboratory/Munitions Directorate, 101 W. Eglin Blvd, Eglin AFB, FL 32542 (United States); De Angelis, R. J. [REEF, University of Florida, 1350 N. Poquito Road, Shalimar, FL 32579 (United States)

2006-07-28

155

Hydrostatic equilibrium and stellar structure in f(R) gravity  

SciTech Connect

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

Capozziello, S.; De Laurentis, M. [Dipartimento di Scienze Fisiche, Universita' di Napoli 'Federico II', INFN Sez. di Napoli, Compl. Univ. di Monte S. Angelo, Edificio G, Via Cinthia, I-80126, Napoli (Italy); Odintsov, S. D. [Institucio Catalana de Recerca i Estudis Avancats (ICREA) and Institut de Ciencies de l Espai (IEEC-CSIC), Campus UAB, Facultat de Ciencies, Torre C5-Par-2a pl, E-08193 Bellaterra, Barcelona (Spain); Stabile, A. [Dipartimento di Ingegneria, Universita del Sannio, Palazzo Dell'Aquila Bosco Lucarelli, Corso Garibaldi, 107-82100, Benevento (Italy)

2011-03-15

156

Investigating the nucleation of protein crystals with hydrostatic pressure  

NASA Astrophysics Data System (ADS)

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 (Mr 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 -46.5 cm3 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.

Kadri, A.; Damak, M.; Jenner, G.; Lorber, B.; Giegé, R.

2003-12-01

157

Cell Membranes Under Hydrostatic Pressure Subjected to Micro-Injection  

NASA Astrophysics Data System (ADS)

The work is concerned with the determination of the mechanical behaviour of cell membranes under uniform hydrostatic pressure subject to micro-injections. For that purpose, assuming that the shape of the deformed cell membrane is axisymmetric a variational statement of the problem is developed on the ground of the so-called spontaneous curvature model. In this setting, the cell membrane is regarded as an axisymmetric surface in the three-dimensional Euclidean space providing a stationary value of the shape energy functional under the constraint of fixed total area and fixed enclosed volume. The corresponding Euler-Lagrange equations and natural boundary conditions are derived, analyzed and used to express the forces and moments in the membrane. Several examples of such surfaces representing possible shapes of cell membranes under pressure subjected to micro injection are determined numerically.

Vassilev, Vassil M.; Kostadinov, Kostadin G.; Mladenov, Ivaïlo M.; Shulev, Assen A.; Stoilov, Georgi I.; Djondjorov, Peter A.

2011-04-01

158

A finite element simulation scheme for biological muscular hydrostats.  

PubMed

An explicit finite element scheme is developed for biological muscular hydrostats such as squid tentacles, octopus arms and elephant trunks. The scheme is implemented by embedding muscle fibers in finite elements. In any given element, the fiber orientation can be assigned arbitrarily and multiple muscle directions can be simulated. The mechanical stress in each muscle fiber is the sum of active and passive parts. The active stress is taken to be a function of activation state, muscle fiber shortening velocity and fiber strain; while the passive stress depends only on the strain. This scheme is tested by simulating extension of a squid tentacle during prey capture; our numerical predictions are in close correspondence with existing experimental results. It is shown that the present finite element scheme can successfully simulate more complex behaviors such as torsion of a squid tentacle and the bending behavior of octopus arms or elephant trunks. PMID:16580021

Liang, Y; McMeeking, R M; Evans, A G

2006-03-31

159

Role of osmotic and hydrostatic pressures in bacteriophage genome ejection.  

PubMed

A critical step in the bacteriophage life cycle is genome ejection into host bacteria. The ejection process for double-stranded DNA phages has been studied thoroughly in vitro, where after triggering with the cellular receptor the genome ejects into a buffer. The experimental data have been interpreted in terms of the decrease in free energy of the densely packed DNA associated with genome ejection. Here we detail a simple model of genome ejection in terms of the hydrostatic and osmotic pressures inside the phage, a bacterium, and a buffer solution or culture medium. We argue that the hydrodynamic flow associated with the water movement from the buffer solution into the phage capsid and further drainage into the bacterial cytoplasm, driven by the osmotic gradient between the bacterial cytoplasm and culture medium, provides an alternative mechanism for phage genome ejection in vivo; the mechanism is perfectly consistent with phage genome ejection in vitro. PMID:23496555

Lemay, Serge G; Panja, Debabrata; Molineux, Ian J

2013-02-20

160

Enhancements to the Pellissier H5 Hydrostatic Level  

NASA Astrophysics Data System (ADS)

The Pellissier H5 Hydrostatic Level is used for applications requiring an order of magnitude improvement in accuracy over conventional optical leveling. The H5 has been used on such applications as the 32-meter radius track for the National Radio Astronomy Observatory (NRAO) Green Bank Telescope (GBT) alidade, the Final Focus Test Beam (FFTB) project at Stanford Linear Accelerator Center (SLAC), the Superconducting Super Collider (SSC), measurements of the Golden Gate Bridge, etc. For the GBT alidade track, 16 benchmarks on a 32-meter radius were measured 3 times over a 2-week period. In each case, the levels closed to better than 0.050 mm over the 200-meter run. The H5 has been well described in the literature by Imfeld, Pellissier, Plouffe, and Ruland [1], so a description will not be repeated in this article. The GBT metrology system [2,3] will employ 12 ground-based laser ranging instruments on a 120-meter radius, i.e., 12 monuments on 62-meter spacing (0.75 km loop). The metrology system will use measured distances only, so the 3-D coordinates of the instrument locations are required in order to do trilateration calculations. The goal is to establish the (x,y,z) coordinates to an accuracy of less than 0.1 mm. The x and y coordinates can be measured by the instruments, but due to the insensitivity of the monument geometry in the z direction, and the need to orient the ground instruments with respect to the gravity vector (to point the telescope), hydrostatic leveling is required.

Parker, David; Shelton, John W.; Radcliff, Bill

161

Optimal induction motor bearing selection  

Microsoft Academic Search

There is no choice in bearing selection on small motors (less than 200 HP), where only anti-friction bearings are available. Likewise, a choice does not exist on larger motors (motors in excess of 2000 HP), where various design requirements leave only the sleeve bearing (or tilting pad bearing) as a viable option. On the intermediate size motors a choice exists.

W. R. Finley; M. M. Hodowanec

2003-01-01

162

Fluid lubricated bearing assembly  

DOEpatents

1. A support for a loaded rotatable shaft comprising in combination on a housing having a fluid-tight cavity encasing an end portion of said shaft, a thrust bearing near the open end of said cavity for supporting the axial thrust of said shaft, said thrust bearing comprising a thrust plate mounted in said housing and a thrust collar mounted on said shaft, said thrust plate having a central opening the peripheral portion of which is hermetically sealed to said housing at the open end of said cavity, and means for supplying a fluid lubricant to said thrust bearing, said thrust bearing having a lubricant-conducting path connecting said lubricant supplying means with the space between said thrust plate and collar intermediate the peripheries thereof, the surfaces of said plate and collar being constructed and arranged to inhibit radial flow of lubricant and, on rotation of said thrust collar, to draw lubricant through said path between the bearing surfaces and to increase the pressure therebetween and in said cavity and thereby exert a supporting force on said end portion of said shaft.

Boorse, Henry A. (Leonia, NJ); Boeker, Gilbert F. (New York, NY); Menke, John R. (New York, NY)

1976-01-01

163

Inelastic Buckling Tests of Ring-Stiffened Cylinders under Hydrostatic Pressure.  

National Technical Information Service (NTIS)

A series of small machined aluminum models were collapsed under external hydrostatic pressure to study the inelastic buckling of near-perfect ring-stiffened cylinders made of strain-hardening materials. The predominant modes of failure were general instab...

L. Boichot T. E. Reynolds

1965-01-01

164

Tests of Machined Multilayer Spherical Shells with Clamped Boundaries under External Hydrostatic Pressure.  

National Technical Information Service (NTIS)

Six spherical shell models with clamped boundaries onsisting of two and four layers were tested under external hydrostatic pressure to explore the feasibility of multilayer construction for application to hydrospace vehicles. In addition, four monolithic ...

K. Nishida

1965-01-01

165

Effect of Hydrostatic Pressure on the Phase Transition Temperatures of a Nematic Liquid Crystal.  

National Technical Information Service (NTIS)

The note reports the effect of hydrostatic pressure on the mesomorphic phase transition temperatures of p-(p-ethoxyphenylazo)-phenyl undecylenate (PPU), which exhibits a nematic range between 65 and 110C at one atmospheric pressure. Pressure up to approxi...

J. D. Boyd C. H. Wang

1973-01-01

166

Effects of Albumin and Urea on Hydrostatic Edema in the Perfused Lung.  

National Technical Information Service (NTIS)

Hydrostatic interstitial pulmonary edema was induced in isolated perfused canine lungs to evaluate the effects of treatment with osmotic agents. In 14 preparations after induced venous hypertension adding fluid weights of 20 gms, 30 gms, 40 gms, or 60 gms...

P. P. Brown J. R. McCurdy R. C. Elkins L. J. Greenfield

1973-01-01

167

HIGH HYDROSTATIC PRESSURE PROCESSING: A POTENTIAL SOLUTION FOR SHELLFISH-BORNE VIRUSES  

Technology Transfer Automated Retrieval System (TEKTRAN)

Molluscan shellfish bioconcentrate enteric viruses from human wastes that are present in the growing waters. Consequently, the consumption of raw shellfish poses considerable risk for contracting illnesses associated with these viruses. High hydrostatic pressure is a new nonthermal sanitizing proc...

168

Influence of High Hydrostatic Pressure Extrusion on Mechanical Behavior of Materials.  

National Technical Information Service (NTIS)

Hydrostatic extrusion is a promising new metal working process. It may provide a practical technique to form useful wrought products from materials difficult or impossible to work by other processes, and it offers the means to develope superior useful pro...

O. D. Sherby J. C. Shyne E. H. Lee

1975-01-01

169

High-pressure resistivity technique for quasi-hydrostatic compression experiments  

NASA Astrophysics Data System (ADS)

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.

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

2013-06-01

170

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

PubMed

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. PMID:23822353

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

2013-06-01

171

String and Sticky Tape Experiments: Light Pipes, Hydrostatics, Surface Tension and a Milk Carton.  

ERIC Educational Resources Information Center

Describes a demonstration of light pipes using low-cost materials, relating it to fiber optics communication. Also provides several experiments in hydrostatics and hydrodynamics using the materials for light pipe. (JM)

Edge, R. D., Ed.

1984-01-01

172

Sensitivity of Spores to Hydrostatic Pressure Mechanisms of Inactivation, Injury and Repair Phase II.  

National Technical Information Service (NTIS)

Over the past fifteen years, it has been established that high- hydrostatic pressure processing (HPP) has significant potential to function as an effective nonthermal method in the destruction of microorganisms in foods with little effect on the sensory q...

D. G. Hoover A. E. Shearer A. Sikes C. P. Dunne

2003-01-01

173

On Variable Hydrostatic Transmission for Road Vehicles, Powered by Supply of Fluid at Constant Pressure.  

National Technical Information Service (NTIS)

Various hydrostatic power transmission systems for automotive applications with power supply at constant pressure and unrestricted flow and with a Volvo Flygmotor variable displacement motor as the principal unit were investigated. Two most promising conc...

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

1981-01-01

174

Metabolic selectivity and growth of Clostridium thermocellum in continuous culture under elevated hydrostatic pressure  

Microsoft Academic Search

The continuous culture of Clostridium thermocellum, a thermophilic bacterium capable of producing ethanol from cellulosic material, is demonstrated at elevated hydrostatic pressure (7.0 MPa, 17.3 MPa) and compared with cultures at atmospheric pressure. A commercial limitation of ethanol production by C. thermocellum is low ethanol yield due to the formation of organic acids (acetate, lactate). At elevated hydrostatic pressure, ethanol:acetate (E\\/A) ratios

G. D. Bothun; B. L. Knutson; J. A. Berberich; H. J. Strobel; S. E. Nokes

2004-01-01

175

The effects of hydrostatic pressure on matrix synthesis in articular cartilage  

Microsoft Academic Search

The direct effects of hydrostatic pressure on matrix synthesis in articular cartilage can be studied independently of the other factors that change during loading. We have found that the influence of hydrostatic pressure on incorporation rates of ³⁵SOâ and (³H)proline into adult bovine articular cartilage slices in vitro depends on the pressure level and on the time at pressure. Pressures

A. C. Hall; J. P. G. Urban; K. A. Gehl

1991-01-01

176

Adaptation of Saccharomyces cerevisiae to high hydrostatic pressure causing growth inhibition  

Microsoft Academic Search

Genome-wide mRNA expression profiles of Saccharomyces cerevisiae growing under hydrostatic pressure were characterized. We selected a hydrostatic pressure of 30MPa at 25°C because yeast cells were able to grow under these conditions, while cell size and complexity were increased after decompression. Functional characterization of pressure-induced genes suggests that genes involved in protein metabolism and membrane metabolism were induced. The response

Hitoshi Iwahashi; Mine Odani; Emi Ishidou; Emiko Kitagawa

2005-01-01

177

Asymmetry of the magnetic field-induced superconducting state BT phase diagram induced by hydrostatic pressure  

Microsoft Academic Search

We investigated, by electrical transport techniques, the effect of hydrostatic pressure on the recently discovered [1,2] magnetic field-induced superconducting state (FISC) of the lambda-(BETS)_2FeCl4 compound. At zero field a small amount of hydrostatic pressure induced, for instance, by the solidification of the pressure medium, considerably ncreases the conductivity of the metallic state at low temperatures. Furthermore, it stabilizes superconductivity at

L. Balicas; J. S. Brooks; K. Storr; S. Uji; H. Kobayashi; A. Kobayashi; M. Tokumoto

2002-01-01

178

Effect of hydrostatic pressure and salinity on the stability of gas hydrates  

Microsoft Academic Search

The distribution of gas in the hydrate and the liquid phases for the two-phase systems methane hydrate-water and methane hydrate-seawater has been calculated as a function of hydrostatic pressure. It is found that at hydrostatic pressures higher than the three-phase hydrate-liquid-gas equilibrium pressure, a two-phase hydrate-liquid equilibrium exists in which the hydrate phase is increasingly enriched in and the liquid

Y. Paul. Handa

1990-01-01

179

Hydrostatic Pressure Study of GaN-Based FETs  

NASA Astrophysics Data System (ADS)

Because of their large breakdown voltage and high saturation velocity, GaN-based field effect transistors (FETs) are best suited for applications that require high power and high frequency, but they face serious reliability problems. In these FETs the charge in the channel results from spontaneous and piezoelectric polarization, so any stress produced during device operation can change the charge in the channel and affect the device's electrical performance. With the aim of better understanding the role of stress, we have studied the current-voltage characteristics of GaN FETs under hydrostatic pressure up to 10 kbar. N-channel FETs were fabricated from GaN-Al0.28Ga0.72N structures grown on SiC substrates. The source-drain current was measured for voltage up to 15V, at various gate voltages, from turn-on (typically -3V) up to 1V. We have observed that for a given source-drain voltage the current increased monotonically with pressure. At 10 kbar, the increase in the saturation current relative to 1 atm was found to be device-dependent, but typically between 5% and 15%. These results, along with the pressure effects on the devices' intrinsic short term degradation and on strongly degraded GaN FETs devices, allow us to speculate about the possible origin of device degradation.

Zhang, Y.; Nielsen, B.; Mendez, E. E.; Jimenez, J.

2007-03-01

180

SIMPLIFIED HYDROSTATIC CARBON BURNING IN WHITE DWARF INTERIORS  

SciTech Connect

We introduce two simplified nuclear networks that can be used in hydrostatic carbon burning reactions occurring in white dwarf interiors. They model the relevant nuclear reactions in carbon-oxygen white dwarfs approaching ignition in Type Ia supernova progenitors, including the effects of the main e {sup -}-captures and {beta}-decays that drive the convective Urca process. They are based on studies of a detailed nuclear network compiled by the authors and are defined by approximate sets of differential equations whose derivations are included in the text. The first network, N1, provides a good first-order estimation of the distribution of ashes and it also provides a simple picture of the main reactions occurring during this phase of evolution. The second network, N2, is a more refined version of N1 and can reproduce the evolution of the main physical properties of the full network to the 5% level. We compare the evolution of the mole fraction of the relevant nuclei, the neutron excess, the photon energy generation, and the neutrino losses between both simplified networks and the detailed reaction network in a fixed temperature and density parcel of gas.

Foerster, Francisco [Departamento de AstronomIa, Universidad de Chile, Casilla 36-D, Santiago (Chile); Lesaffre, Pierre [Laboratoire de Radioastronomie, 24 rue Lhomond, 75231 Paris Cedex 05 (France); Podsiadlowski, Philipp [Department of Physics, University of Oxford, Oxford OX1 3RH (United Kingdom)

2010-10-15

181

Low hydrostatic head electrolyte addition to fuel cell stacks  

DOEpatents

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.

Kothmann, Richard E. (Churchill Boro, PA)

1983-01-01

182

Simplified Hydrostatic Carbon Burning in White Dwarf Interiors  

NASA Astrophysics Data System (ADS)

We introduce two simplified nuclear networks that can be used in hydrostatic carbon burning reactions occurring in white dwarf interiors. They model the relevant nuclear reactions in carbon-oxygen white dwarfs approaching ignition in Type Ia supernova progenitors, including the effects of the main e --captures and ?-decays that drive the convective Urca process. They are based on studies of a detailed nuclear network compiled by the authors and are defined by approximate sets of differential equations whose derivations are included in the text. The first network, N1, provides a good first-order estimation of the distribution of ashes and it also provides a simple picture of the main reactions occurring during this phase of evolution. The second network, N2, is a more refined version of N1 and can reproduce the evolution of the main physical properties of the full network to the 5% level. We compare the evolution of the mole fraction of the relevant nuclei, the neutron excess, the photon energy generation, and the neutrino losses between both simplified networks and the detailed reaction network in a fixed temperature and density parcel of gas.

Förster, Francisco; Lesaffre, Pierre; Podsiadlowski, Philipp

2010-10-01

183

A CANDIDATE DETECTION OF THE FIRST HYDROSTATIC CORE  

SciTech Connect

The first hydrostatic core (FHSC) represents a very early phase in the low-mass star formation process, after collapse of the parent core has begun but before a true protostar has formed. This large (few AU), cool (100 K), pressure-supported core of molecular hydrogen is expected from theory, but has yet to be observationally verified. Here, we present observations of an excellent candidate for the FHSC phase: Per-Bolo 58, a dense core in Perseus that was previously believed to be starless. The 70 {mu}m flux of 65 mJy, from new deep Spitzer MIPS observations, is consistent with that expected for the FHSC. A low signal-to-noise detection at 24 {mu}m leaves open the possibility that Per-Bolo 58 could be a very low luminosity protostar, however. We utilize radiative transfer models to determine the best-fitting FHSC and protostar models to the spectral energy distribution and 2.9 mm visibilities of Per-Bolo 58. The source is consistent with an FHSC with some source of lower opacity through the envelope allowing 24 {mu}m emission to escape; a small outflow cavity and a cavity in the envelope are both possible. While we are unable to rule out the presence of a protostar, if present it would be one of the lowest luminosity protostellar objects yet observed, with an internal luminosity of {approx}0.01 L {sub sun}.

Enoch, Melissa L. [Department of Astronomy, University of California at Berkeley, 601 Campbell Hall, Berkeley, CA 94720 (United States); Lee, Jeong-Eun [Department of Astronomy and Space Science, Astrophysical Research Center for the Structure and Evolution of the Cosmos, Sejong University, Seoul 143-747 (Korea, Republic of); Harvey, Paul; Dunham, Michael M. [Department of Astronomy, University of Texas at Austin, 1 University Station, C1400, Austin, TX 78712 (United States); Schnee, Scott, E-mail: menoch@berkeley.ed [National Research Council Canada, Herzberg Institute of Astrophysics, 5071 West Saanich Road, Victoria BC V9E 2E7 (Canada)

2010-10-10

184

Carbon Nanotubes under Hydrostatic Pressure: The Deformation Transition  

NASA Astrophysics Data System (ADS)

Isolated single-wall carbon nanotubes (SWNTs) deform from their usual cylindrical shape to a collapsed or oval cross-section upon increase of hydrostatic pressure. We use classical molecular-dynamics simulations to study the structural properties of isolated SWNTs under pressure near this deformation transition. Within our model, we find two distinct behaviors depending on the nanotube diameter d. For d > dc 12 ,WNTs collapse from a circle to a peanut or racetrack cross-section at a critical pressure Pc with a discontinuous change in volume. The van der Waals interactions between the opposite walls of the tube play a crucial role in driving this discontinuous transition. For a range of pressures, both circle and collapsed cross-sections are locally stable and the system shows hysteresis. For d < dc, the transition is continuous, from a circle to an oval cross-section. RBC acknowledges financial support from the John Simon Guggenheim Memorial Foundation and Brazilian funding agencies CNPq, CAPES, FAPERJ, Instituto de Nanociências, FUJB-UFRJ and PRONEX-MCT. This work was supported by NSF Grant No. DMR04-39768 and by the Director, Office of Science, Office of Basic Energy Sciences, Division of Materials Sciences and Engineering, U.S. DOE under Contract No. DE-AC03-76SF00098. Computational resources have been provided by NERSC and NPACI.

Cohen, Marvin L.; Capaz, Rodrigo B.; Tangney, Paul

2005-03-01

185

Effects of hydrostatic pressure on TMJ disc cells.  

PubMed

The effects of mechanical stimuli on TMJ disc cells have yet to be investigated. This study examined for the first time the effect of constant and intermittent hydrostatic pressure (HP) on TMJ disc cells. Guided by studies on articular chondrocytes, the chosen amplitude was 10 MPa, the frequency was 1 Hz for intermittent HP, and the duration was 4 h. A one-time application of the HP stimulus was applied in 2-D and 3-D for gene expression studies. A duty cycle of 2 days on, 1 day off for 1 week of HP stimulus was used for biochemical content studies. In monolayer, the intermittent HP regimen increased collagen II expression, while constant HP increased collagen I expression when compared to the non-loaded control. However, the overall expression of collagen I was much higher than collagen II in both constant and intermittent HP. The expression results correlated well with gross morphology, histology, and biochemical content. At Week 1, the intermittent HP group had a lower content of collagen, 7.5 +/- 0.2 microg/construct, than the non-loaded control group, 18.2 +/- 4.0 microg/construct. The constant HP group showed the highest amount of collagen, 24.5 +/- 1.6 microg/construct. These data show that constant HP at 10 MPa for 4 h produces more collagen I than do the non-loaded control or intermittent HP at 10 MPa and 1 Hz. PMID:16771641

Almarza, Alejandro J; Athanasiou, Kyriacos A

2006-05-01

186

Wavelength tuning of laser diodes using hydrostatic pressure  

NASA Astrophysics Data System (ADS)

Direct bandgap of most III-V semiconductors (AlGaAs, InGaAs, InGaP, InAs) increases with hydrostatic pressure at the rate of about 10 meV per kbar. Thus the emission wavelength of semiconductor lasers shifts to the blue under the application of high pressure. We demonstrate that this effect can be used for wavelength tuning of laser diodes in a very wide spectral range. Using the specially designed liquid pressure cell working up to 20 kbar the 1550 nm laser was tuned down to 1270 nm, the 1300 nm laser was tuned down to 1100 nm, and the 980 nm laser was tuned down to 840 nm. The emitted light passes through the sapphire window or through the fiber directly coupled to the laser. The threshold current and the quantum efficiency for the 980 nm laser remained constant with pressure, for the two other lasers the thresholds decreased with pressure. Thus we obtained the constant emission power in the full tuning range. We hope that this compact device will find applications as a tool for characterization of some optical network devices or parts of optical transmission lines.

Dybala, Filip; Adamiec, Pawel; Bercha, Artem; Bohdan, Roland; Trzeciakowski, Witold

2003-06-01

187

Amos Bear Gets Hurt.  

ERIC Educational Resources Information Center

A three-day experiment set up by an early childhood teacher explored Piaget's view that children younger than age eight lack ability to take another's point of view. The experiment focused on a bear, the class mascot, and observations of children's empathetic behavior toward its "injury." Age-related differences in the children's responses were…

Read, Laurie

1995-01-01

188

High Performance Bearing Study.  

National Technical Information Service (NTIS)

A feasibility investigation was performed to identify the probable advantages, problem areas, and the degree of feasibility of applying air lubricated bearings to an advanced class of U.S. Air Force complex-cycle aircraft engines. Three P+WA engines incor...

W. D. Waldron W. E. Young

1972-01-01

189

Engine Hybrid Ceramic Bearings.  

National Technical Information Service (NTIS)

The objective of this program was the development of additional performance data and condition-monitoring techniques for silicon nitride (Si3N4) bearings. Induced-defect testing was performed to assess the ability of silicon nitride balls to withstand the...

M. Rhoads M. Bashyam

1994-01-01

190

Fluid Lubricated Bearing Assembly.  

National Technical Information Service (NTIS)

A support for a loaded rotatable shaft is described. The device consists of: a housing having a fluid-tight cavity encasing an end portion of the shaft; a thrust bearing near the open end of the cavity for supporting the axial thrust of the shaft, the thr...

H. A. Boorse G. F. Boeker J. R. Menke

1976-01-01

191

Axial Thrust Bearing.  

National Technical Information Service (NTIS)

The axial thrust bearing intended, for example, for a turbo-compressor used to supercharge an internal combustion engine, contains fixed and moving thrust elements in contact with the working shaft; it is distinguished by the fact that in order to increas...

L. A. Samarin S. T. Sharov V. A. Rakhmanov V. E. Vinyar Y. A. Trofimov

1971-01-01

192

Hybrid superconductor magnet bearings  

NASA Astrophysics Data System (ADS)

Hybrid superconductor magnet bearings (HSMB's) utilize high temperature superconductors (HTS's) together with permanent magnets to form a frictionless interface between relatively rotating parts. They are low mass, stable, and do not incur expenditure of energy during normal operation. There is no direct physical contact between rotor and stator, and hence there is no wear and tear. However, just as any other applications of HTS's, it requires a very cold temperature to function. Whereas this might be perceived as a disadvantage on earth, it is of no great concern in space or on the moon. To astronomers, the moon is an excellent site for an observatory, but the cold and dusty vacuum environment on the moon precludes the use of mechanical bearings on the telescope mounts. Furthermore, drive mechanisms with very fine steps, and hence bearings with extremely low friction are needed to track a star from the moon, because the moon rotates very slowly. All aspects considered, the HSMB is about the only candidate that fits in naturally. Here, we present a design for one such bearing, capable of supporting a telescope that weighs about 3 lbs on Earth.

Chu, Wei-Kan

1995-04-01

193

Bear vs Bee  

NSDL National Science Digital Library

This interactive Java applet is a game that challenges a student to solve problems by using logic and rudimentary engineering skills. The goal in each case is to create a conveyance that gets the bear to the pot of honey, avoiding the bees. The game has 32 stages of increasing complexity.

2012-01-01

194

Solving bearing overheating problems  

Microsoft Academic Search

Overheating is a major indicator, along with vibration and noise, of an underlying problem affecting a bearing or related components. Because normal operating temperatures vary widely from one application to another, no single temperature is a reliable sign of overheating in every situation. By observing an application when it is running smoothly, a technician can establish a benchmark temperature for

Jendzurski

1995-01-01

195

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

SciTech Connect

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

Luettge, U.; Nobel, P.S.

1984-07-01

196

10. DETAIL VIEW OF END BEARING CONDITION SHOWING MOVEABLE BEARING ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

10. DETAIL VIEW OF END BEARING CONDITION SHOWING MOVEABLE BEARING AT SOUTHEAST END OF LOWER ROAD LEVEL - Mahoning Avenue Pratt Double-Deck Bridge, Spanning Mill Creek at Mahoning Avenue (C.R. 319), Youngstown, Mahoning County, OH

197

Magnetic bearings grow more attractive  

SciTech Connect

Advances in materials and electronics have enabled designers to devise simpler, smaller magnetic bearings. As a result, costs have dropped, widening the applications for these very-low-friction devices. Avcon (Advanced Controls Technology) has patented a permanent-magnet bias actively controlled bearing. Here high-energy rare earth permanent-magnet materials supply the basic bearing load levitation, while servo-driven electromagnets generate stabilization and centering forces for motion contol. Previous heavy-duty magnetic bearings used electromagnets entirely for suspension and control, which led to large bearings and control systems with higher power requirements. Avcon has developed several types of permanent-magnet bias bearings. The simplest is the radial repulsion bearing. Avcon's homopolar permanent-magnet bias active bearing is the most versatile of the company's designs.

Not Available

1993-10-01

198

Vygotsky and the Three Bears  

ERIC Educational Resources Information Center

Peggy Kulczewski, a kindergarten classroom teacher, remembers the day when students enjoyed a story she told them from the book "The Three Bears". The students' discussion about comparison of the bears was very helpful to the whole group.

Kulczewski, Peggy

2004-01-01

199

Hydrostatic strain enhancement in laterally confined SiGe nanostripes  

NASA Astrophysics Data System (ADS)

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

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

2013-09-01

200

Retinal ganglion cell line apoptosis induced by hydrostatic pressure.  

PubMed

Cellular responses to changes in pressure are implicated in numerous disease processes. In glaucoma apoptosis of retinal ganglion cells (RGCs) is associated with elevated intra-ocular pressure, however, the exact cellular mechanisms remain unclear. We have previously shown that pressure can induce apoptosis in B35 and PC12 neuronal cell lines, using an in vitro model for pressure elevation. A novel RGC line allows us to study the effects of pressure on retinal neurons. 'RGC-5' cultures were subjected to elevated ambient hydrostatic pressure conditions in our model. Experimental pressure conditions were 100 mm Hg and 30 mm Hg, representing acute (high) and chronic (lower-pressure) glaucoma, and 15 mm Hg for normal intra-ocular pressure, set above atmospheric pressure for 2 h. Negative controls were treated identically except for the application of pressure, while positive controls were generated by treatment with a known apoptotic stimulus. Apoptosis was determined by a combination of cell morphology and specific TUNEL and Annexin V fluorescent markers. These were assessed simultaneously by laser scanning cytometry (LSC), which also enabled quantitative marker analysis. RGC-5 neurons showed a significantly increased proportion of apoptotic cells compared with controls; maximal at 100 mm Hg, moderate at 30 mm Hg and not statistically significant at 15 mm Hg. This graded response, proportionate to the level of pressure elevation, is representative of the severity of analogous clinical settings (acute, chronic glaucoma and normal). These results complement earlier findings of pressure-induced apoptosis in other neuronal cultures. They suggest the possibility of novel mechanisms of pressure-related mechanotransduction and cell death, relevant to the pathogenesis of diseases such as glaucoma. PMID:16638612

Agar, Ashish; Li, Shaojuan; Agarwal, Neeraj; Coroneo, Minas T; Hill, Mark A

2006-04-25

201

A conservative method for hydrostatic flow in isentropic coordinates  

NASA Astrophysics Data System (ADS)

Although our climate is ultimately driven by (nonuniform) solar heating, many aspects of the flow can be understood qualitatively from forcing-free and frictionless dynamics. In the limit of zero forcing and dissipation, our weather system falls under the realm of Hamiltonian fluid dynamics and the flow conserves potential vorticity (PV), energy and phase-space structure. We have found a conservative numerical scheme for a hydrostatic atmosphere based on a mixed Eulerian-Lagrangian approach, the so-called parcel formulation [1]. For adiabatic flow, the entropy is materially conserved. Under stable stratifications, we introduce isentropic coordinates to simplify the governing equations. The entropic direction is discretized using finite elements. The discretization of horizontal Lagrangian label space (from infinitesimal fluid parcels to discrete fluid particles) yields a discrete Poisson bracket. New is that we apply the Hamiltonian Particle-Mesh method [2], and view the potential as an Eulerian function, reconstructed from the particle data. The use of an Eulerian grid makes the method more efficient and stable. The Hamiltonian consists of a Lagrangian kinetic energy and an Eulerian potential energy. The discrete system of ODE's is thus a Hamiltonian system conserving mass, PV, energy and phase-space structure. If we incorporate a symplectic time integrator, the resulting fully discrete system conserves energy approximately without any drift in energy. Several challenging (nonlinear) solutions will be tested, such a flow over a rising bump. Also, preliminary results for bottom-intersecting isentropes will be demonstrated. REFERENCES [1] O. Bokhove and M. Oliver, Parcel Eulerian-Lagrangian fluid dynamics for rotating geophysical flows, Proc. Roy. Soc. A. 462, pp. 2563-2573 (2006) [2] J. Frank, G. Gottwald, S. Reich, A Hamiltonian particle-mesh method for the rotating shallow-water equations, Lecture Notes in Computational Science and Engineering, Vol. 26, Springer, Heidelberg, pp. 131-142 (2002)

Peeters, B.; Bokhove, O.; Frank, J.

2010-05-01

202

Hydrostatic and osmotic pressure activated channel in plant vacuole  

PubMed Central

The vacuolar membrane of red beet vacuoles contains a channel which was not gated by voltage or Ca2+ ions. Its unit conductance was 20 pS in 200 mM symmetrical KCl solutions. It was stretch activated: the conductance remained constant but the probability of opening was increased by suction or pressure applied to a membrane patch. A 1.5-kNm-2 suction applied to isolated patches or a 0.08-kNm-2 pressure applied to a 45-?m diameter vacuole induced an e-fold change in the mean current. A 75% inhibition of the channel current was obtained with 10 ?M Gd3+ on the cytoplasmic side. The channel was more permeable for K+ than for Cl- (PK/PCl ? 3). A possible clustering for this channel was suggested by the recordings of the patch current. The channel properties were not significantly affected by a change in sorbitol osmolality in the solutions under isoosmotic conditions, between 0.6 and 1 mol/kg sorbitol. However, the channel was very sensitive to an osmotic gradient. A 0.2-mol/kg sorbitol gradient induced a two-fold increase in unit conductance and a thirty-fold increase in the mean patch current of the channel. A current was measured, when the osmotic gradient was the only driving force applied to the vacuolar membrane. The hydrostatic and osmotic pressure (HOP) activated channel described in this paper could be gated in vivo condition by a change in osmolality, without the need of a change in the turgor pressure in the cell. The HOP channel represents a possible example of an osmoreceptor for plant cells.

Alexandre, Joel; Lassalles, Jean-Paul

1991-01-01

203

Magnetocaloric effect of Er5Si4 under hydrostatic pressure  

NASA Astrophysics Data System (ADS)

The magnetocaloric effect (MCE) of the compound Er5Si4 has been investigated as a function of the applied magnetic field (up to 50 kOe) and the hydrostatic pressure (from ambient pressure up to 9 kbar). At constant magnetic field change, increasing the pressure up to 1.4 kbar induces a global rise of the magnetic entropy change, |?Smag| , with the peak at TC?30K growing from 14.9 to 20.1J/kgK . Between 1.4 and 9 kbar, the size and shape of the |?Smag| vs T curve remain nearly constant but the peak moves to higher temperatures and stabilizes above 3.5 kbar at Ttilde 36K . Contrary to many other R5(SixGe1-x)4 compounds, the magnetocaloric effect in Er5Si4 does not originate from the simultaneous field-induced magnetic and structural transformations since previous studies of the compound have demonstrated that moderate steady magnetic fields are not strong enough to induce the M?O(I) transformation at the atmospheric pressure. However, the pressure dependence of the MCE is associated with pressure-induced M?O(I) structural transformation that takes place in Er5Si4 . The increase in the magnetic entropy change occurs because of a modification of the magnetic coupling derived from the differences in the interlayer bonding in the M and O(I) states. This gives rise to an enhancement of the ferromagnetic interactions in the O(I) phase with respect to the ambient pressure M state, resulting in a stronger saturation magnetization and a higher Curie temperature, i.e., TCM=30K and TCO(I)=36K .

Arnold, Z.; Magen, C.; Morellon, L.; Algarabel, P. A.; Kamarad, J.; Ibarra, M. R.; Pecharsky, V. K.; Gschneidner, K. A., Jr.

2009-04-01

204

Regulation of gene expression in intervertebral disc cells by low and high hydrostatic pressure.  

PubMed

Intervertebral disc structures are exposed to wide ranges of intradiscal hydrostatic pressure during different loading exercises and are at their minimum during lying or relaxed sitting and at maximum during lifting weights with a round back. We hypothesize that these different loading magnitudes influence the intervertebral disc (IVD) by alteration of disc matrix turnover depending on their magnitudes. Therefore the aim of this study was to assess changes in gene expression of human nucleus cells after the application of low hydrostatic pressure (0.25 MPa) and high hydrostatic pressure (2.5 MPa). IVD cells isolated from the nucleus of human (n = 18) and bovine (n = 24 from four animals) disc biopsies were seeded into three-dimensional collagen type-I matrices and exposed to the different loading magnitudes by specially developed pressure chambers. The lower pressure range (0.25 MPa, 30 min, 0.1 Hz) was applied with a recently published device by using an external compression cylinder. For the application of higher loads (2.5 MPa, 30 min, 0.1 Hz) the cell-loaded collagen gels were sealed into sterile bags with culture medium and stimulated in a newly developed water-filled compression cylinder by using a loading frame. These methods allowed the comparison of loading regimes in a wide physiological range under an equal three-dimensional culture conditions. Cells were harvested 24 h after the end of stimulation and changes in the expression of genes known to influence IVD matrix turnover (collagen-I, collagen-II, aggrecan, MMP1, MMP2, MMP3, MMP13) were analyzed by real-time RT-PCR. A Wilcoxon signed-rank test(1) and a Wilcoxon 2-sample test(2) were performed to detect differences between the stimulated and control samples(1) and differences between low and high hydrostatic pressure(2). Multiple testing was considered by adjusting the p value appropriately. Both regimes of hydrostatic pressure influenced gene expression in nucleus cells with opposite tendencies for the matrix forming proteins aggrecan and collagen type-I in response to the two different pressure magnitudes: Low hydrostatic-pressure (0.25 MPa) tended to increase collagen-I and aggrecan expression of human nucleus cells (P < 0.05) but only to a small degree. High hydrostatic pressure (2.5 MPa) tended to decrease gene expression of all anabolic proteins with significant effects on aggrecan expression of nucleus cells (P = 0.004). Low hydrostatic pressure had no influence on the expression of matrix metalloproteinases (MMP1, MMP2, MMP3 and MMP13). In contrast, high hydrostatic pressure tended to increase the expression of MMP1, MMP3 and MMP13 of human nucleus cells with high individual-individual variations. The decreased expression of aggrecan (P = 0.008) and collagen type II (P = 0.023) and the increased MMP3 expression (P = 0.008) in response to high hydrostatic pressure could be confirmed in additional experiments with bovine nucleus cells. These results suggest that hydrostatic pressure as one of the physiological stimuli of the IVD may influence matrix turnover in a magnitude dependent way. Low hydrostatic pressure (0.25 MPa) has quite small influences with a tendency to anabolic effects, whereas high hydrostatic pressure (2.5 MPa) tends to decrease the matrix protein expression with a tendency to increase some matrix-turnover enzymes. Therefore, hydrostatic pressure may regulate disc matrix turnover in a dose-dependent way. PMID:16680448

Neidlinger-Wilke, Cornelia; Würtz, Karin; Urban, Jill P G; Börm, Wolfgang; Arand, Markus; Ignatius, Anita; Wilke, Hans-Joachim; Claes, Lutz E

2006-05-06

205

Rotating plug bearing and seal  

DOEpatents

A bearing and seal structure for nuclear reactors utilizing rotating plugs above the nuclear reactor vessel. The structure permits lubrication of bearings and seals of the rotating plugs without risk of the lubricant draining into the reactor vessel below. The structure permits lubrication by utilizing a rotating outer race bearing.

Wade, Elman E. (Ruffs Dale, PA)

1977-01-01

206

Bearing Race Support without Distortion.  

National Technical Information Service (NTIS)

A race for a bearing, which is mountable to a mount, has an annular bearing surface with a center axis defining an axis of rotation for the bearing and mutually perpendicular radial and transverse directions relative thereto. The race also has a radial wa...

D. A. Nyhus J. V. Alexander R. Soloski

2002-01-01

207

On Sandwiched Magnetic Bearing Design  

Microsoft Academic Search

This paper presents an innovative design for magnetic poles used in active magnetic bearings (AMBs). The proposed hybrid sandwiched magnetic pole design not only practically reduces the bearing size, but also dramatically diminishes its cost. The magnetic force to counterbalance the gravity of the rotor is provided by the embedded permanent magnets (PMs), while the electromagnetic bearing is merely used

Nan-Chyuan Tsai; Sheng-Liang Hsu

2007-01-01

208

The Polar Bear Game  

NSDL National Science Digital Library

In this game, which is similar to Petals Around the Rose (cataloged separately), a player rolls 5 dice and asks the participants, âHow many polar bears are around the ice holes?â The participants try to figure out the riddle (rules of the game) by studying the dice arrangements and the answers that correspond. This webpage extends the game to have players also determine the number of fish and plankton.

2010-10-24

209

Grizzly bears and forestry  

Microsoft Academic Search

We examined if clearcuts were selected as habitats by grizzly bears (Ursus arctos L.) in west-central Alberta during three seasons: hypophagia, early hyperphagia, and late hyperphagia. Our objectives were to describe seasonal habitat selection of clearcuts using resource selection functions at two scales. At the first scale, we assessed patch or third-order selection by comparing use (radiotelemetry) with study area-wide

Scott E. Nielsen; Mark S. Boyce; Gordon B. Stenhouse

2004-01-01

210

Determination of the cohesive strength of low-carbon steel (0.03% C) by means of high hydrostatic pressures  

Microsoft Academic Search

Using an extrapolation of tensile data obtained under varying amounts of hydrostatic compression to positive hydrostatic pressure (hydrostatic tension), the cohesive strength of a low-carbon steel (0.03% C) has been determined. These preliminary results indicate a value of 54.6 kg\\/mm2, somewhat lower than obtained by other investigators. Increased strength with decreasing temperature occurs and is consistent with other observations.

Marek Brandes

1966-01-01

211

Bearing for liquid metal pump  

DOEpatents

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.

Dickinson, Robert J. (Shaler Township, Allegheny County, PA); Wasko, John (Plum Borough, PA); Pennell, William E. (Unity Township, Allegheny County, PA)

1984-01-01

212

The effects of hydrostatic pressure on the compressive mechanical behavior of L12 Al3Ti-based intermetallic  

NASA Astrophysics Data System (ADS)

A Mn-modified Ll2 Al3Ti-base intermetallic was subjected to compressive deformation at room temperature under superimposed hydrostatic pressures up to 1000 MPa. It is found that its yield strength is essentially unaffected by hydrostatic pressure. The apparent work-hardening rate of true stress-strain curves increases substantially with increasing hydrostatic pressure. Vickers microhardness of pressurized samples always increases with increasing compressive strain, indicating the work-hardening behavior, but it is independent of the superimposed hydrostatic pressure up to 1000 MPa. The density of microcracks (cm/cm2) observed in specimens compressed under hydrostatic pressure increases with increasing compressive strain for each level of pressure. At each constant compressive strain, the corresponding density of microcracks is higher for specimens tested under 170 MPa hydrostatic pressure than that for specimens tested in the 400 to 1000 MPa hydrostatic pressure range. This may imply that besides propagation, the nucleation stage may also be suppressed by a superimposed hydrostatic pressure. It is proposed that both the cataclastic (characteristic for deformation of some rocks) and plastic deformation occur simultaneously during compressive deformation of Ti trialuminides under hydrostatic pressure.

Winnicka, M. B.; Witczak, Z.; Varin, R. A.

1994-08-01

213

Stability of finite journal bearings from bearings--linear and nonlinear bearing forces  

Microsoft Academic Search

The paper investigates the relationship between the stability contour determined from the nonlinear simulation and that from the linear theory. The nonlinear bearing forces are directly obtained from the bearing pressure distribution which is solved from the Reynolds equation at each journal position. It is found that the critical speeds in the case of nonlinear bearing forces are the same

A. K. Tieu; Z. L. Qiu

1995-01-01

214

VIBRATIONS OF HYBRID CERAMIC BALL BEARINGS  

Microsoft Academic Search

Hybrid ceramic ball bearings with silicone nitride balls and steel rings were tested, and the vibration characteristics were compared with those of conventional steel ball bearings. In this study, two types of hybrid ceramic ball bearings and two types of conventional steel ball bearings were used as test bearings. The test bearings were operated under several rotational speeds and axial

H. Ohta; K. Kobayashi

1996-01-01

215

Dialogue for Kids Wild About Bears Sleepy Bear Lesson Plan  

NSDL National Science Digital Library

Each winter, bears hunker down, slow their metabolisms, and pretty much wait out the winter in the safety of some sort of den. This lesson plan, from Idaho Public Television, is a fun way to illustrate to children (probably elementary grades primarily) the process of hibernation. At this site, educators are given the complete lesson plan instructions as well as several links to all sorts of great resources, including links to information on: Bear Diet, Home Range, Reproduction, Bear Research, People and Bears, more Classroom Activities, and more. And, the great addition to the site is a link to a 30-minute video about bears. While the site is somewhat focused on Idaho-specific bear information, teachers should be able to easily integrate the lesson no matter where you are.

216

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

PubMed

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

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

2011-09-10

217

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

PubMed Central

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.

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

2011-01-01

218

Regulations associated with the hydrostatic testing of natural gas pipelines. Volume 2. Topical report, May 1992  

SciTech Connect

The report examines environmental regulatory issues related to the discharge of hydrostatic test waters generated from the integrity testing of natural gas pipelines. Hydrostatic testing, and proper environmental management of discharged waters is required by DOT regulations. However, disposal of water used to conduct a hydrostatic pipeline test is regulated on a state-by-state basis. State-specific requirements vary widely, ranging from an authorization letter to a complete NPDES permit. In some cases, both federal and state permits must be obtained. Monitoring may be required before and during discharge. While some states have established state-wide discharge limits, the majority of the monitoring requirements are determined on a site-specific basis and can include a variety of parameters. The report is Volume 2 of a 5-volume report series.

Bruderly, L.M.; Halapin, T.A.; Fillo, J.P.

1992-05-01

219

Remanent magnetization and coercivity of rocks under hydrostatic pressure up to 1.4 GPa  

NASA Astrophysics Data System (ADS)

We designed an Isothermal Remanent Magnetization (IRM) acquisition system based on permanent magnets and sized to accommodate an amagnetic hydrostatic pressure cell. This pressure cell fits in a superconducting rock magnetometer, allowing for the measurement of remanent magnetization of pressurized samples. With this system, we determined the coercivity of remanence (Bcr) at different hydrostatic pressures up to 1.4 GPa for rock and dispersed mineral samples with various magnetic mineralogy and domain state. IRM and Bcr are nearly identical before compression and after decompression, indicating no permanent changes in the magnetic properties during pressure cycling. Hydrostatic pressure up to 1.4 GPa does not significantly increases IRM under pressure except for multidomain pyrrhotite and magnetite which show an increase of about 40%. Relative increase of Bcr under pressure is mild, except for a near single domain titanomagnetite where Bcr doubles.

Demory, F.; Rochette, P.; Gattacceca, J.; Gabriel, T.; Bezaeva, N. S.

2013-08-01

220

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

SciTech Connect

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

Magi, M.; Freivald, A. (AB, Goteborg); Anderson, I.

1981-05-01

221

Bearing Dynamic Coefficients of Flexible-Pad Journal Bearings  

Microsoft Academic Search

The application of flexible-pad journal bearings for high-speed rotating machinery has recently gained attention from equipment manufacturers for its simplicity of one-piece design which can eliminate the manufacturing tolerance stack-up and possible lower functional power loss. This paper presents a general method for the calculation of bearing dynamic coefficients of flexible-pad journal bearings. These coefficients are critical to the rotor

Wen Jeng Chen

1995-01-01

222

Bears on Ice  

NSDL National Science Digital Library

Bears on Ice allows students to experience Antarctica through the eyes of two Geobears, Berkley and OzGold, who sailed on the Aurora Australis with their Australian friend and helper, Gordon Bain. These Bears have traveled to Antarctica and back and have had many adventures. They have brought back information and photographs that will help students share in their adventures. Links to more information and thinking questions are an integral part of this section. The Data pages contain numerical data about the voyage, such as the position of the ship (latitude and longitude) as well as many environmental conditions, like sea temperature, air temperature, or any ice that was encountered. The data lend themselves well to graphing and other math activities. The Information pages contain first-person accounts that go into more detail about some of their more exciting adventures, or ship procedures that need a bit more explanation than is offered in the daily reports. These, along with the linked Special Reports, can serve as reliable sources for research reports.

223

Magnetic field and hydrostatic pressure effects on electron Raman scattering in anisotropic quantum dots  

NASA Astrophysics Data System (ADS)

We have investigated the electron Raman scattering process of a two-dimensional anisotropic quantum dot. With typical semiconducting GaAs based materials, the differential cross-section has been examined on the basis of the computed energies and wave functions. We also studied the effects of external magnetic field and hydrostatic pressure on the Raman scattering in anisotropic quantum dots. The results show that electron Raman scattering in anisotropic QDs is strongly affected by the degree of anisotropy, dot size, applied magnetic field and hydrostatic pressure. It is possible to control the frequency shift and the peak intensity of the Raman spectrum in anisotropic QDs by varying these factors.

Xie, Wenfang

2013-09-01

224

Development of composite spherical bearing  

Microsoft Academic Search

Carbon–phenolic woven composite materials are employed in heavy-duty bearings due to their inherent self-lubricating properties and thermal stability. In this work, a composite spherical bearing (CSB) composed of carbon–phenolic composite race and steel ball is developed to solve the seizure of conventional metal–metal spherical bearings for the elevation driving mechanism (EDM) of a future battle tank. In order to eliminate

Byung Chul Kim; Dong Chang Park; Hak Sung Kim; Dai Gil Lee

2006-01-01

225

General demographics survey for hydrostatic test water discharges from natural gas pipelines. Topical report, March-October 1995  

Microsoft Academic Search

The report summarizes information regarding the quantity and frequency of water discharged from mainline transmission hydrostatic testing of new and existing natural gas pipelines. The research was used to determine the range and distribution of discharge frequency and water volumes associated with hydrostatic testing. The information presented in this report was obtained from a survey conducted during the period March

J. T. Tallon; J. M. Fankulewski; J. P. Fillo

1995-01-01

226

Research Trends on Magnetic Bearings  

NASA Astrophysics Data System (ADS)

Use of magnetic bearings for high-speed rotor and application in clean environment or in special circumstance have been gradually increasing. This article overviews research trends and application presented before the Eighth International Symposium on Magnetic Bearings (ISMB-8). Interesting research topics are the combined realization of motor and magnetic bearing, low loss magnetic bearings and self-sensing techniques. New application fields include small spindles for data storage devices, energy storage flywheels, and artificial heart pumps. Various new technologies are reported related to these new application fields.

Okada, Yohji; Nonami, Kenzo

227

Equation of hydrostatic equilibrium in the theory of a planetary figure  

SciTech Connect

A numerical method is developed for solving the equation of hydrostatic equilibrium with allowance for corrections for the asphericity of the planet. Radial density distributions are found for a set of polytropes with indices of from 1 to 2 in planets with the parameters of Jupiter, Saturn, Uranus, and Neptune.

Bobrov, A.M.; Vasil'ev, P.P.; Zharkov, V.N.; Trubitsyn, V.P.

1978-07-01

228

Role of a Hydrostatic Pressure Gradient in the Formation of Early Ischemic Brain Edema  

Microsoft Academic Search

Summary: We studied whether a hydrostatic pressure gradient between arterial blood and brain tissue plays a role in the formation of early ischemic cerebral edema after middle cerebral artery (MCA) occlusion in cats. Tissue pressure, regional CBF, and water content were measured from the cortex in the core and the peripheral zone of brain normally perfused by the MCA. Intraluminal

Shizuo Hatashita; Julian T. Hoff

1986-01-01

229

Increased renal interstitial hydrostatic pressure causes c- fos expression in the rat's spinal cord dorsal horn  

Microsoft Academic Search

To describe a sympathetic afferent circuit, interstitial hydrostatic pressure in the left kidney was increased in anesthetized rats for 1.5 h to activate renal mechanoreceptor afferents. Following renal afferent stimulation, the number of immunocytochemically stained cells for the immediate early gene c-fos was increased within the dorsal horn of the spinal cord. Relative to the surgical control procedure, increasing renal

Greg K Fitch; Kaushik P Patel; Mark L Weiss

1997-01-01

230

Evaluation of high hydrostatic pressure effects on bovine red blood cells and platelets  

Microsoft Academic Search

The objective of this study was to investigate the effects of high hydrostatic pressure (HHP) on the stability of red blood cells (RBCs) and platelets. Bovine blood cells (n=5) were treated with the pressure of 55, 110, 154 and 220 MPa at 25 °C for 5 min. Light microscopy, atomic force microscopy and flow cytometry studies revealed that RBCs were morphologically stable up

Cagatay Ceylan; Mete Severcan; Faruk Bozoglu; Feride Severcan

2009-01-01

231

Potential for High Hydrostatic Pressure Processing to Control Quarantine Insects in Fruit  

Technology Transfer Automated Retrieval System (TEKTRAN)

Tests were conducted to determine the potential for high hydrostatic pressure (HPP) to control codling moth, Cydia pomonella (L.) and Western cherry fruit fly, Rhagoletis indifferens Curran. Apples with larvae or eggs of codling moth were treated 24 h and 72 h, respectively, after infestation at a s...

232

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

Code of Federal Regulations, 2011 CFR

...pressure vessel, multiplied by the ratio of the stress value âSâ at the test temperature to the stress value âSâ at the design temperature for...No ratio less than one shall be used. The stress resulting from the hydrostatic test...

2011-10-01

233

Research on the deformation strengthening mechanism of a tungsten heavy alloy by hydrostatic extrusion  

Microsoft Academic Search

The microstructure mechanical properties of the 93 tungsten alloy and the deformation strengthening mechanism of the tungsten alloy by hydrostatic extrusion are studied by static and dynamic tensile experiments, quantitative metallography experiments and the transmission electron microscopy (TEM) analysis in this paper. Varied laws on tungsten grain's effective contiguity on different deformation directions and dislocation densities in tungsten grain and

Zhang Zhaohui; Wang Fuchi

2001-01-01

234

Temperature effects on behavior and survival of marine invertebrates exposed to variations in hydrostatic pressure  

Microsoft Academic Search

Investigation into the pressure resistance of 8 intertidal species belonging to the genera, Uca, Sesurma, Talorchestia and Littorina from the Northern Gulf of Mexico and Panama sheds light on the relationships between temperature and hydrostatic-pressure resistance. Generally, increasing temperature increases the pressure required to elicit reversible reactions such as “increased activity” and tetany, or paralysis, wheroas increasing temperature generally evokes

R. J. Menzies; R. Y. George

1972-01-01

235

Anaerobic Bacterial Corrosion of Metals in Sea Water at Elevated Hydrostatic Pressures.  

National Technical Information Service (NTIS)

The effects of hydrostatic pressures on the anaerobic corrosion of ingot iron, E.C. Grade aluminum, and 316-type stainless steel by three marine sulfate-reducing bacterial cultures were examined. Depending upon the period of exposure, all three cultures w...

C. A. Willingham

1971-01-01

236

Electrochemical Aspects of Hydrogen Permeation in Iron at High Hydrostatic Pressure.  

National Technical Information Service (NTIS)

A high pressure system containing an electrochemical method for continuous hydrogen permeation determination through metal foil is described for use at hydrostatic pressures up to 20,000 psi. The diffusion coefficient of hydrogen in Armco iron at 21C is 0...

J. J. DeLuccia K. Yamakawa L. Nanis

1969-01-01

237

Influence of hydrostatic pressure on the thermal properties of polymers at low temperatures  

Microsoft Academic Search

The thermal conductivity ? of polycarbonate (PC) has been measured in the temperature range 3–150K under hydrostatic pressure up to 1.3GPa [Geilenkeuser, R., Weise, F. and Jäckel, M., Czech. J. Physics, 1996, 46, 2251 (Proc. LT 21, Prag, August 1996)]. A strong influence of pressure on ? has been observed over the entire temperature range. Additional measurements of the pressure

Manfred Jäckel; Frank Weise; Jörg Opitz; Rolf Geilenkeuser

1998-01-01

238

Failure of Thick-Walled Concrete Spheres Subjected to Hydrostatic Loading.  

National Technical Information Service (NTIS)

Two modes of failure for hollow concrete spheres subjected to hydrostatic pressure loadings are discussed, and the experimental results are presented. The first mode of failure was crack development in the plane of the concrete wall, and the second mode w...

H. H. Haynes R. A. Hoofnagle

1970-01-01

239

Synergistic effect of high hydrostatic pressure pretreatment and osmotic stress on mass transfer during osmotic dehydration  

Microsoft Academic Search

During osmotic removal of water from foods, the osmotic dehydration front moves from the surface of the food in contact with the surrounding osmotic solution to the centre, which results in disintegration of cells due to osmotic stress. When the food is pretreated with high hydrostatic pressure (HHP), it also results in cell permeabilisation. The cell permeabilisation index (Zp, as

N. K. Rastogi; A. Angersbach; D. Knorr

2000-01-01

240

Collapse of double-walled carbon nanotube bundles under hydrostatic pressure  

Microsoft Academic Search

We use classical molecular dynamics simulations to study the collapse of single (SWNT) and double-walled (DWNT) carbon nanotube bundles under hydrostatic pressure. The collapse pressure (pc) varies as 1\\/R3 , where R is the SWNT radius or the DWNT effective radius. The bundles show ˜30% hysteresis and the hexagonally close packed lattice is completely restored on decompression. The pc of

Vikram Gadagkar; Prabal K. Maiti; Yves Lansac; A. Jagota; A. K. Sood

2006-01-01

241

Filtration Coefficient of the Axon Membrane As Measured with Hydrostatic and Osmotic Methods  

Microsoft Academic Search

The hydraulic conductivity of the membranes surrounding the giant axon of the squid, Dosidicus gigas, was measured. In some axons the axoplasm was partially removed by suction. Perfusion was then established by insertion of a second pipette. In other axons the axoplasm was left intact and only one pipette was inserted. In both groups hydrostatic pressure was applied by means

FERNANDO F. VARGAS

1968-01-01

242

High Hydrostatic Pressure as a Method to Reduce Microbial Contamination of Porcine Blood Plasma  

Microsoft Academic Search

The suitability of high hydrostatic pressure as an alternative method to produce porcine blood plasma with a sufficient microbial stability without affecting its functional properties was evaluated. The effects of high pressure on plasma microorganisms were highly dependent on processing temperature. Treatments of 15 min at 450 MPa carried out at 5 'C led to reductions of about 90% in

D. Pares; E. Saguer; M. Toldra; C. Carretero

2001-01-01

243

Effects of High Hydrostatic Pressurised Treatment on Porcine Blood Red Cells Fraction  

Microsoft Academic Search

The aim of this study was to determine the optimum conditions for the application of high hydrostatic pressure treatment (HHP) on the red blood cells (RBC) fraction from porcine blood. HHP was applied under varying conditions of pressure (400, 450 and 500 MPa), temperature (5, 20 and 40°C) and time (5, 15 and 30 min), and the effects on the

M. Toldrà; A. Busquets; E. Saguer; D. Parés; C. Carretero

2002-01-01

244

The Effects of Hydrostatic Pressure on Synthetic-Rope Buoyancy in Fresh and Salt Water.  

National Technical Information Service (NTIS)

Tests were conducted to determine the effect of hydrostatic pressure on the buoyancy of a large diameter synthetic rope. This report presents the results of those tests and discusses their meaning in terms of the compressibility effects of the rope materi...

G. T. Griffin W. A. Watkins

1979-01-01

245

Perception of constant hydrostatic pressure. A physiological basis for the vertical stratification of marine habitats  

Microsoft Academic Search

Summary This paper reports an experimental demonstration of the ability of sessile marine animals (Balanus balanus L., Crustacea, Cirripedia) to perceive constant hydrostatic pressure. The results suggest the presence inBalanus of a previously unknown sensory system with a tonic response. Such a system may also be present in freely moving animals, but be masked by their locomotor activity.

H.-H. Sommer; D. Barnett; N. Fleming; M. Teitelman; J. Morph

1981-01-01

246

Thermal effects in high density polyethylene and low density polyethylene at high hydrostatic pressures  

Microsoft Academic Search

The temperature changes as a result of rapid hydrostatic pressure applications are reported for high density polyethylene (HDPE) and low density polyethylene (LDPE) in the reference temperature range from 298 to 423 K and in the pressure range from 13.8 to 200 MN m-2. The adiabatic temperature changes were found to be a function of pressure and temperature. A curve

E. L. Rodriguez; F. E. Filisko

1987-01-01

247

Functional Improvement of Milk Whey Proteins Induced by High Hydrostatic Pressure  

Microsoft Academic Search

High pressure is emerging as a new processing technology that produces particular changes in the molecular structure of proteins and thus gives rise to new properties inaccessible via conventional methods of protein modification. This review deals with the main effects of high hydrostatic pressure on the physicochemical characteristics of milk whey proteins and how modifications in their structural properties contribute

Rosina López-Fandiño

2006-01-01

248

Reliability-based load and resistance factor design of composite pressure vessel under external hydrostatic pressure  

Microsoft Academic Search

A reliability-based load and resistance factor design procedure for subsea composite pressure vessel subjected to external hydrostatic pressure is presented. The failure criterion for defining the performance function is considered as buckling. A sensitivity analysis is conducted to research influences of statistical characteristics of variables on the partial safety factors and the thickness of pressure vessel. The results shows the

Baoping Cai; Yonghong Liu; Zengkai Liu; Xiaojie Tian; Renjie Ji; Hang Li

249

An innovative approach for sorptive separation of amphiphilic biomolecules applying high hydrostatic pressure  

Microsoft Academic Search

An innovative approach to separate amphiphilic biomolecules in a fixed bed adsorption experimental set-up is discussed and experimental results are presented. High hydrostatic pressure of up to 360MPa is utilized to control the sorption equilibrium. Major advantages of this approach are that no auxiliary substances are required for the separation that have to be removed afterwards. Furthermore, of the two

Bernd Niemeyer; Jan Jansen

2007-01-01

250

Fundamental evaluation of the impact of high Hydrostatic Pressure on oat batters  

Microsoft Academic Search

The use of grains alternative to wheat or rye is a challenging task for cereal technologists, and currently new technologies are under investigation as tools to improve the performances of these alternative grains. In this work the effects of high Hydrostatic Pressure (HP) on oat batters were investigated. Oat batters were treated for 10 min at 200, 300, 350, 400 or

Edith K. Hüttner; Fabio Dal Bello; Kaisa Poutanen; Elke K. Arendt

2009-01-01

251

Influence of Hydrostatic Pressure and Temperature on the Deep Donor Levels of Sulfur in Silicon  

Microsoft Academic Search

The Hall effect and resistivity of silicon doped with sulfur have been measured as a function of temperature in the range between 300 K and temperatures as low as 50 K (the latter depending on the sample in question) and as a function of hydrostatic pressure up to 8 kbar at various temperatures in this range. From the Hall-effect data,

D. L. Camphausen; H. M. James; R. J. Sladek

1970-01-01

252

MICROFILAMENTS ARE INVOLVED IN RENAL CELL RESPONSES TO SUSTAINED HYDROSTATIC PRESSURE  

Microsoft Academic Search

Purpose:Increased pressures within renal interstitial fluid, as associated with a number of renal pathologies, could affect cell function and gene expression. The long-term objective of this research is to elucidate kidney cell responses to pathological hydrostatic pressures.

JULIE S. MARTIN; LAUREN S. BROWN; KAREN M. HABERSTROH

2005-01-01

253

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

ERIC Educational Resources Information Center

|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,…

Pelton, Rick; Espy, John

254

A hydrostatic mesoscale model using finite element and finite difference techniques  

Microsoft Academic Search

A mesoscale model capable of treating variable terrain is described herein. The model, based on the hydrostatic and anelastic approximations, has been developed with a primary goal of providing, in real time, physically realistic and accurate wind fields and atmospheric stability information to drive a pollutant transport model in emergency response situations. A hybrid method which employs both finite element

S. T. Chan; Leone J. M. Jr; R. L. Lee

1988-01-01

255

EFFECT OF SEEPAGE-INDUCED NON-HYDROSTATIC PRESSURE DISTRIBUTION ON BEDLOAD TRANSPORT AND BED MORPHODYNAMICS  

Microsoft Academic Search

The Shields number, or Shields stress, provides a classical non- dimensionalization expressing the relative mobility of a sediment particle on the bed of a river. It is not commonly recognized, however, that the Shields number implicitly contains the assumption of a hydrostatic pressure distribution in the water immersing the particles. While such an assumption is accurate for a wide range

Simona Francalanci; Gary Parker; Luca Solari

2006-01-01

256

The hydrostatic corer Selcore—a tool for sediment sampling and geophysical site characterization  

Microsoft Academic Search

Hydrostatic energy is used to power an active device for sediment sampling and geophysical site characterization. In the Selcore design, a steel tank with built-in drive unit constitutes the core head. The difference between ambient water pressure and atmospheric pressure in the tank provides the energy. The Selcore prototype enters the seabed as a gravity corer and automatically shifts into

Yngve Kristoffersen; Eldar Lien; Kjetil Festervoll; Sigurd Ree; Kåre Åardahl; Øyvind Hosøy

2006-01-01

257

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

PubMed

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. PMID:23504511

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

258

Hydrostatic pressure effect on the electrical resistivity of Ni80P20 amorphous alloys  

NASA Astrophysics Data System (ADS)

An influence of hydrostatic pressure on electronic transport in amorphous alloys Ni80P20 has been studied. The nonmonotonic behaviour of the pressure resistance coefficient is explained in terms of the Ziman-Faber theory by differences in resistance change velocities at the expansion of the Fermi surface and a topological short-range order.

Krysov, V. I.; Krysova, S. K.; Maksimov, I. S.; Medvedev, Yu. V.

1999-04-01

259

MODERN HYDROSTATIC DRIVE SYSTEMS IN THE LIGHT OF DYNAMICAL SYSTEMS THEORY  

Microsoft Academic Search

Dynamic effects in hydrostatic drives are strongly related to the compressibility of the hydraulic fluid. In a proper nondimensional scaling of the state equations the small compressibility parameter leads to singularly perturbed differential equations. For the hydraulic servo-drive this singular perturbed system is investigated by means of a center manifold approach. The reduced problem exhibits discontinuities when the servo-valve passes

R. Scheidl; B. Manhartsgruber; G. Riha

260

The Migration of Polar Bears.  

National Technical Information Service (NTIS)

As the polar bear roams widely over its Arctic habitat in quest of its principal food--seal meat, little is known about him. Now a technique is at hand that promises to fill some of the gaps in our knowledge of the polar bear's life. The technique involve...

V. Flyger M. R. Townsend

1968-01-01

261

Polar Bears and Climate Change  

NSDL National Science Digital Library

The issue-focused, peer reviewed article discusses how a warming climate is altering sea ice conditions, which affects polar bears in many ways, including more difficulty in getting to and hunting prey, fewer den areas and lower cub survival, increased interactions between bears and humans, and lower survival rate of the species in general.

Andrew E. Derocher (University of Alberta, Canada;)

2008-05-01

262

GEOPHAGY BY YELLOWSTONE GRIZZLY BEARS  

Microsoft Academic Search

We documented 12 sites in the Yellowstone ecosystem where grizzly bears (Ursus arctos horribilis) had purposefully consumed soil (an activity known as geophagy). We also documented soil in numerous grizzly bear feces. Geophagy primarily occurred at sites barren of vegetation where surficial geology had been modified by geothermal activity. There was no evidence of ungulate use at most sites. Purposeful

GERALD I. GREEN; ROGER SWALLEY

263

Teflon-Lined Bearing Improvement.  

National Technical Information Service (NTIS)

The patent application describes a method of repairing or retrofitting the teflon fabric liner of a spherical and/or self-aligning bearing, that has separated due to poor bonding with the bearing surface, with a metal-backed, teflon liner that includes a ...

P. R. Eklund

1972-01-01

264

Geophagy by yellowstone grizzly bears  

USGS Publications Warehouse

We documented 12 sites in the Yellowstone ecosystem where grizzly bears (Ursus arctos horribilis) had purposefully consumed soil (an activity known as geophagy). We also documented soil in numerous grizzly bear feces. Geophagy primarily occurred at sites barren of vegetation where surficial geology had been modified by geothermal activity. There was no evidence of ungulate use at most sites. Purposeful consumption of soil by bears peaked first from March to May and again from August to October, synchronous with peaks in consumption of ungulate meat and mushrooms. Geophageous soils were distinguished from ungulate mineral licks and soils in general by exceptionally high concentrations of potassium (K) and high concentrations of magnesium (Mg) and sulphur (S). Our results do not support the hypotheses that bears were consuming soil to detoxify secondary compounds in grazed foliage, as postulated for primates, or to supplement dietary sodium, as known for ungulates. Our results suggest that grizzly bears could have been consuming soil as an anti-diarrheal.

Mattson, D. J.; Green, G. I.; Swalley, R.

1999-01-01

265

Thermally Activated Seizure of Angular Contact Bearings  

Microsoft Academic Search

Equations have been developed relating friction-power to bearing element temperatures for the particular case of prelubricated or lightly lubricated ball bearings. An expression is derived for the change in relative dimensions of an angular contact bearing, as determined by the temperature gradient across the bearing. A second expression is found for the accommodation of the bearing to expansion, this accommodation

R. A. Burton; H. E. Staph

1967-01-01

266

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

Federal Register 2010, 2011, 2012, 2013

...Federal Energy Regulatory Commission [Project Nos. 2710-061; 2712-078] Black Bear Hydro Partners, LLC and Black Bear Development Holdings, LLC and Black Bear SO, LLC; Notice of Application for Partial Transfer of Licenses, and...

2012-11-26

267

Effects of bearing cleaning and lube environment on bearing performance  

NASA Astrophysics Data System (ADS)

Running torque data of SR6 ball bearings are presented for different temperatures and speeds. The data are discussed in contrast to generally used torque prediction models and point out the need to obtain empirical data in critical applications. Also, the effects of changing bearing washing techniques from old, universally used CFC-based systems to CFC-free aqueous/alkaline solutions are discussed. Data on wettability, torque and lubricant life using SR3 ball bearings are presented. In general, performance is improved using the new aqueous washing techniques.

Ward, Peter C.

1995-05-01

268

Thermal Interactions in Rolling Bearing Dynamics.  

National Technical Information Service (NTIS)

Numerical enhancements to the established bearing dynamics computer code, Advanced Dynamics of Rolling Elements (ADORE), have been accomplished for improved computation of bearing heat generation and geometrical variation in bearing element dimensions. Th...

P. K. Gupta

2002-01-01

269

HYDROSTATIC GAS CONSTRAINTS ON SUPERMASSIVE BLACK HOLE MASSES: IMPLICATIONS FOR HYDROSTATIC EQUILIBRIUM AND DYNAMICAL MODELING IN A SAMPLE OF EARLY-TYPE GALAXIES  

SciTech Connect

We present new mass measurements for the supermassive black holes (SMBHs) in the centers of three early-type galaxies. The gas pressure in the surrounding, hot interstellar medium (ISM) is measured through spatially resolved spectroscopy with the Chandra X-ray Observatory, allowing the SMBH mass (M {sub BH}) to be inferred directly under the hydrostatic approximation. This technique does not require calibration against other SMBH measurement methods and its accuracy depends only on the ISM being close to hydrostatic, which is supported by the smooth X-ray isophotes of the galaxies. Combined with results from our recent study of the elliptical galaxy NGC 4649, this brings the number of galaxies with SMBHs measured in this way to four. Of these, three already have mass determinations from the kinematics of either the stars or a central gas disk, and hence join only a handful of galaxies with M {sub BH} measured by more than one technique. We find good agreement between the different methods, providing support for the assumptions implicit in both the hydrostatic and the dynamical models. The stellar mass-to-light ratios for each galaxy inferred by our technique are in agreement with the predictions of stellar population synthesis models assuming a Kroupa initial mass function (IMF). This concurrence implies that no more than {approx}10%-20% of the ISM pressure is nonthermal, unless there is a conspiracy between the shape of the IMF and nonthermal pressure. Finally, we compute Bondi accretion rates (M-dot{sub bondi}), finding that the two galaxies with the highest M-dot{sub bondi} exhibit little evidence of X-ray cavities, suggesting that the correlation with the active galactic nuclei jet power takes time to be established.

Humphrey, Philip J.; Buote, David A. [Department of Physics and Astronomy, University of California at Irvine, 4129 Frederick Reines Hall, Irvine, CA 92697-4575 (United States); Brighenti, Fabrizio [Dipartimento di Astronomia, Universita di Bologna, Via Ranzani 1, Bologna 40127 (Italy); Gebhardt, Karl [Astronomy Department, University of Texas, Austin, TX 78712 (United States); Mathews, William G. [University of California Observatories, Lick Observatory, University of California, Santa Cruz, CA 95064 (United States)

2009-10-01

270

Comparison of hydrostatic extrusion versus wire drawing as a method of producing Nbsub3Sn superconducting wire  

NASA Astrophysics Data System (ADS)

The conventional manufacturing process for Nb3Sn multifilamentary superconducting wire is a combination of hot extrusion and wire drawing. An alternative process, cold hydrostatic extrusion, was developed. All experimental data pertaining to the hydrostatic extrusion process are presented, and a comparison is made between the two manufacturing methods. The results show that monofilamentary Nb3Sn wire produced by hydrostatic extrusion not only has good superconducting properties, but also that larger reductions are achieved per pass, and fewer and shorter intermediate anneals are required in its manufacture.

Thadani, V.; Avitzur, B.; Chou, Y. T.; Luhman, T. S.

1981-01-01

271

Bears, Big and Little. Young Discovery Library Series.  

ERIC Educational Resources Information Center

|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)…

Pfeffer, Pierre

272

Yellowstone Grizzly Bear Investigations 1997.  

National Technical Information Service (NTIS)

The Interagency Grizzly Bear Study Team (IGBST) was initiated in 1973 and is a cooperative effort of the National Park Service, Forest Service, and since 1974 the States of Idaho, Montana, and Wyoming. The IGBST conducts research that provides information...

C. C. Schwartz M. A. Haroldson

1998-01-01

273

Yellowstone Grizzly Bear Investigations 1992.  

National Technical Information Service (NTIS)

The Interagency Grizzly Bear Study Team (IGBST) was initiated in 1973 and is a cooperative effort of the National Park Service, Forest Service, and since 1974 the States of Idaho, Montana, and Wyoming. The IGBST conducts research that provides information...

R. R. Knight B. M. Blanchard D. J. Mattson

1993-01-01

274

Yellowstone Grizzly Bear Investigations 1993.  

National Technical Information Service (NTIS)

The Interagency Grizzly Bear Study Team (IGBST) was initiated in 1973 and is a cooperative effort of the National Park Service, Forest Service, and since 1974 the States of Idaho, Montana, and Wyoming. The IGBST conducts research that provides information...

R. R. Knight B. M. Blanchard

1994-01-01

275

Yellowstone Grizzly Bear Investigations 1998.  

National Technical Information Service (NTIS)

The Interagency Grizzly Bear Study Team (IGBST) was initiated in 1973 and is a cooperative effort of the National Park Service, Forest Service, and since 1974 the States of Idaho, Montana, and Wyoming. The IGBST conducts research that provides information...

C. C. Schwartz M. A. Haroldson

1999-01-01

276

Yellowstone Grizzly Bear Investigations 1994.  

National Technical Information Service (NTIS)

The Interagency Grizzly Bear Study Team (IGBST) was initiated in 1973 and is a cooperative effort of the National Park Service, Forest Service, and since 1974 the States of Idaho, Montana, and Wyoming. The IGBST conducts research that provides information...

R. R. Knight B. M. Blanchard

1995-01-01

277

Yellowstone Grizzly Bear Investigations 1990.  

National Technical Information Service (NTIS)

The Interagency Grizzly Bear Study Team (IGBST) was initiated in 1973 and is a cooperative effort of the National Park Service, Forest Service, and since 1974 the States of Idaho, Montana, and Wyoming. The IGBST conducts research that provides information...

R. R. Knight B. M. Blanchard D. J. Mattson

1991-01-01

278

Yellowstone Grizzly Bear Investigations 1991.  

National Technical Information Service (NTIS)

The Interagency Grizzly Bear Study Team (IGBST) was initiated in 1973 and is a cooperative effort of the National Park Service, Forest Service, and since 1974 the States of Idaho, Montana, and Wyoming. The IGBST conducts research that provides information...

R. R. Knight B. M. Blanchard D. J. Mattson

1992-01-01

279

Mixed-mu superconducting bearings  

DOEpatents

A mixed-mu superconducting bearing is disclosed including a ferrite structure disposed for rotation adjacent a stationary superconductor material structure and a stationary permanent magnet structure. The ferrite structure is levitated by said stationary permanent magnet structure. 9 figs.

Hull, J.R.; Mulcahy, T.M.

1998-03-03

280

Ceramic Gas Bearing Material Evaluation.  

National Technical Information Service (NTIS)

Flat washer specimens were experimentally tested under conditions simulating start-stop and continuous rubbing contact of a gas-lubricated thrust bearing. Minimum surface damage with a constant and low value of the friction coefficient were criteria for j...

J. T. McCabe P. R. Albrecht E. F. Finkin

1972-01-01

281

Yellowstone Grizzly Bear Investigations 2000.  

National Technical Information Service (NTIS)

It was recognized as early as 1973, that in order to understand the dynamics of grizzly bears (Ursus arctos horribilis) throughout the Greater Yellowstone Ecosystem (GYE), there was a need for a centralized research group responsible for collecting, manag...

C. C. Schwartz M. A. Haroldson

2001-01-01

282

Yellowstone Grizzly Bear Investigations 1999.  

National Technical Information Service (NTIS)

It was recognized as early as 1973, that in order to understand the dynamics of grizzly bears (Ursus arctos horribilis) throughout the Greater Yellowstone Area, there was a need for a centralized research group responsible for collecting, managing, analyz...

C. C. Schwartz M. A. Haroldson

2000-01-01

283

Myrmecophagy by Yellowstone grizzly bears  

USGS Publications Warehouse

I used data collected during a study of radio-marked grizzly bears (Ursus arctos horribilis) in the Yellowstone region from 1977 to 1992 to investigate myrmecophagy by this population. Although generally not an important source of energy for the bears (averaging 8 mm long) nested in logs over small ants (6 mm long) nested under stones. Optimal conditions for consumption of ants occurred on the warmest sites with ample substrate suitable for ant nests. For ants in mounds, this occurred at low elevations at non-forested sites. For ants in logs, this occurred at low elevations or on southerly aspects where there was abundant, large-diameter, well-decomposed woody debris under an open forest canopy. Grizzly bears selected moderately decomposed logs 4a??5 dm in diameter at midpoint. Ants will likely become a more important food for Yellowstone's grizzly bears as currently important foods decline, owing to disease and warming of the regional climate.

Mattson, D. J.

2001-01-01

284

Lateral Dampers for Thrust Bearings.  

National Technical Information Service (NTIS)

The development of lateral damping schemes for thrust bearings was examined, ranking their applicability to various engine classes, selecting the best concept for each engine class and performing an in-depth evaluation. Five major engine classes were cons...

D. H. Hibner D. R. Szafir

1985-01-01

285

Bearing capacity of desiccated tailings  

SciTech Connect

The development of matric suctions in soils contributes to their shear strength, resulting in an enhanced factor of safety against bearing-capacity failure. In this paper, matric suction profiles of desiccated mine tailings are predicted from a steady-state solution for evaporative conditions, and from an isothermal mathematical model that simulates liquid and vapor water flow through soils. The shear-strength envelope with respect to matric suction is established by testing reconstituted tailings samples in a modified triaxial cell, in which matric suction can be controlled. The contribution of matric suction to the shear strength is interpreted as an additional apparent cohesion for use in bearing-capacity calculations. Because of the nonlinearity of the shear-strength profile, a numerical method of analysis is adopted to predict the ultimate bearing capacity of the desiccated tailings. A subsequent decrease in bearing capacity following 2D water infiltration into a partially capped tailings deposit and accompanying suction loss is investigated.

Rassam, D.W.; Williams, D.J. [Univ. of Queensland, Brisbane, Queensland (Australia). Dept. of Civil Engineering

1999-07-01

286

Evaluation of Shuttle Turbopump Bearings.  

National Technical Information Service (NTIS)

Because the high pressure turbopumps used on the space shuttle main engine (SSME) are high speed machines and rotor dynamics analysis of these units is very complicated, it was considered necessary to verify calculated turbomachinery shaft bearing loads b...

K. D. Dufrane J. W. Kannel

1978-01-01

287

Superconducting composite for magnetic bearings  

SciTech Connect

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.

Rigney, T.K. II

1995-10-10

288

Teddy Bear Line-Up  

NSDL National Science Digital Library

This problem requires children to develop logical reasoning and promotes using visualization to plan ahead. Students are presented with a line of four blue, then four red followed by four yellow and finally four green bears and are asked to rearrange them using the least number of moves so that no two bears of the same color are next to each other. The Teachers' Notes page offers rationale, suggestions for implementation, discussion questions, and an idea for support and extension.

2009-04-01

289

Testing and Lubrication for Single Race Bearings  

SciTech Connect

Three ES and H-compatible lubricants (Environment, Safety and Health) for single race bearing applications and one hybrid-material single race bearings were evaluated and compared against single race bearings with trichlorotrifluoroethane (Freon) deposition of low molecular weight polytetrafluoroethylene (PTFE) bearing lubricant extracted from Vydax{trademark}. Vydax is a product manufactured by DuPont consisting of various molecular weights of PTFE suspended in trichlorotrifluoroethane (Freon), which is an ozone-depleting solvent. Vydax has been used as a bearing lubricant in stronglink mechanisms since 1974. Hybrid bearings with silicon nitride balls and molded glass-nylon-Teflon retainers, bearings lubricated with titanium carbide (TiC) on the balls, bearings lubricated with sputtered MoS{sub 2} on races and retainers, and bearings lubricated with electrophoretically deposited MoS{sub 2} were evaluated. The bearings were maintained in a preloaded state in bearing cartridges during cycling and vibration tests. Bearings with electrophoretically deposited MoS{sub 2} performed as well as bearings lubricated with Vydax and were the best performing candidate. All candidates were suitable for low preload applications. Bearings with TiC coated balls and bearings lubricated with sputtered MoS{sub 2} on the races and retainers performed well at high preloads, though not as well as bearings lubricated with electrophoretic deposition of MoS{sub 2}. Bearings with silicon nitride balls were not suitable for high preload applications.

Steinhoff, R.G.

1998-03-04

290

Controlled hydrostatic sinus elevation: a novel method of elevating the sinus membrane.  

PubMed

Maxillary sinus elevation surgery has been practiced successfully over the past several decades with good outcomes, but tears and perforations still occur in significant numbers. The presumed cause of these problems is the fact that all methods currently used place "point sources" of lifting pressure on the Schneiderian membrane. A new procedure, controlled hydrostatic sinus lift, is presented herein as a safer, more controlled "lifting pressure" which simultaneously places equal force per square millimeter of bone-membrane interface. Hydraulic pressure in a closed system places equal pressure on all surfaces within the system, thereby eliminating "point sources" of pressure and gently elevating the Schneiderian membrane equally at all points of attachment. This controlled hydrostatic sinus lift procedure is accomplished by using a calibrated, hand-controlled pump and in-line pressure sensor meter. PMID:22067599

Kao, Daniel W K; DeHaven, Harold A

2011-12-01

291

Genomic expression pattern in Saccharomyces cerevisiae cells in response to high hydrostatic pressure.  

PubMed

Gene expression patterns in response to hydrostatic pressure were determined by whole genome microarray hybridization. Functional classification of the 274 genes affected by pressure treatment of 200 MPa for 30 min revealed a stress response expression profile. The majority of the >2-fold upregulated genes were involved in stress defense and carbohydrate metabolism while most of the repressed ones were in cell cycle progression and protein synthesis categories. Furthermore, uncharacterized genes were among the 10 highest expressed sequences and represented 45% of the total upregulated genes. The results of this study revealed a hydrostatic pressure-specific stress response pattern and suggested interesting information about the mechanisms involved in adaptation of cells to a high-pressure environment. PMID:14706843

Fernandes, Patricia M B; Domitrovic, Tatiana; Kao, Camilla M; Kurtenbach, Eleonora

2004-01-01

292

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

PubMed Central

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

Lin, Jih-Pai

2009-01-01

293

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

PubMed

Burgessia bella is a characteristic Burgess Shale arthropod (508 Ma), but the unusual preservation of its telson in both straight and bent modes leads to contradictory interpretations of its function. A reinvestigation of the fossil material, including burial attitudes, combined with a comparison with the decay sequence and mechanics of the telson in living Limulus, demonstrates that the telson of Burgessia was flexible in its relaxed state but could be stiffened in life. Evidence of fluid within the telson indicates that this manoeuvrability was achieved by changes in hydrostatic pressure and muscular control. The dual mode in the Burgessia telson is, to my knowledge, the first documented among fossil arthropods. It indicates that the requirement for a rigid telson, which is resolved by a thick sclerotized cuticle in most arthropods, may first have been achieved by hydrostatic means. PMID:19324649

Lin, Jih-Pai

2009-03-04

294

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

NASA Astrophysics Data System (ADS)

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

Cai, Yingxiang; Yu, Jie; Wu, Songtao

2007-04-01

295

Soda-lime silicate glass under hydrostatic pressure and indentation: a micro-Raman study  

NASA Astrophysics Data System (ADS)

Raman micro-spectroscopy is used to analyse the plastic behaviour of window glass (a soda-lime silicate glass) under high hydrostatic pressure and Vickers indentation. We show pressure-induced irreversible structural changes, notably an increase of Q2 species at the expense of Q3. For the first time, a very accurate {Raman} \\leftrightarrow {pressure} calibration curve has been established. Local density variations of a Vickers indented window glass have been characterized by micro-Raman mapping using a high spatial resolution device. The effects of glass depolymerization on indentation and hydrostatic compression are discussed. Differences between window glass and pure SiO2 glass behaviour under high stresses are also highlighted and analysed at a local scale.

Deschamps, T.; Martinet, C.; Bruneel, J. L.; Champagnon, B.

2011-01-01

296

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

PubMed

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. PMID:23807390

Fu, Yinan; Wand, A Joshua

2013-06-27

297

Elongation and Random Orientation of Bovine Endothelial Cells in Response to Hydrostatic Pressure: Comparison with Response to Shear Stress  

NASA Astrophysics Data System (ADS)

Morphological responses of cultured bovine endothelial cells (ECs) exposed to hydrostatic pressure were investigated. ECs were exposed to physiological blood pressure under a hydrostatic head of culture medium for 24 hours. Pressured ECs exhibited marked elongation and orientation with the random direction, together with development of centrally located, thick stress fibers. Pressured ECs also exhibited multilayered structure unlike under control conditions. The area and the shape index value significantly decreased after exposure to hydrostatic pressure, which were in good agreement with the results from conventional flow-imposed experiments. In contrast, a tortuosity index, which was newly introduced to represent cell shape tortuosity, significantly increased for pressured ECs, while sheared ECs had no difference in turtuosity index from control. In addition, pressured ECs aligned with no predominant direction, while sheared ECs aligned in the flow direction. These results indicate that ECs can respond very specifically to the type of imposed mechanical stimuli such as hydrostatic pressure and fluid shear stress.

Sugaya, Yoshiaki; Sakamoto, Naoya; Ohashi, Toshiro; Sato, Masaaki

298

Specifics of Excitation and Action of Explosion at High Hydrostatic Pressures (Osobennosti Vozbuzhdeniya i Deistviya Vzryva pri Bolshikh Gidrostaticheskikh Davleniyakh).  

National Technical Information Service (NTIS)

A report is presented on experimental studies of the propagation conditions of an explosive wave through explosive media at high hydrostatic pressures, and on the conditions of detonation of the media.

E. A. Levin S. A. Lovlya Y. P. Nelasov

1971-01-01

299

Destruction of Spoilage and Pathogenic Bacteria by Hydrostatic Pressure and Electroporation in Combination with Biopreservatives. Phase 2.  

National Technical Information Service (NTIS)

Escherichia coli O157:H7, Salmonella typhimurium ATCC 14028, Listeria monocytogenes Scott A, Leuconostoc mesenteroides Ly and Lactobacillus sake FMl were evaluated for their sensitivity to either hydrostatic pressure (HP) or electroporation (EP) in combin...

N. Kalchayanand B. Ray A. Sikes C. P. Dunne

1997-01-01

300

Changes in structure and functional properties of whey proteins induced by high hydrostatic pressure: A review  

Microsoft Academic Search

High hydrostatic pressure (HHP) is an alternative technology to heat processing for food product modifications. It does not\\u000a cause environmental pollution and eliminates the use of chemical additives in food products. This review covers the research\\u000a conducted to understand the effect of HHP on structure and functional properties of whey proteins. In this paper, the mechanism\\u000a underlying pressure-induced changes in

Xiaoming Liu; Jia Ning; Stephanie Clark

2009-01-01

301

V-waves, bow shocks, and wakes in supercritical hydrostatic flow  

Microsoft Academic Search

The structure of the bow shock, V-wave, and the related wave drag and wake in supercritical ambient flow are investigated for homogeneous hydrostatic single-layer flow with a free surface over an isolated two-dimensional (i.e. h(x;y)) obstacle. The two control parameters for this physical system are the ratio of obstacle height to fluid depth and the Froude number F = U=

Q INGFANG J IANG; RONALD B. S MITH

302

Hydrostatic Modelling of Active Region EUV and X-ray Emission  

Microsoft Academic Search

The hydrostatic modeling of active region NOAA 10963 coronal EUV and X-ray emission is presented. The model considers three-dimensional magnetic field structure obtained by the extraplation of the longitudinal magnetogram in potential or linear force-free approximation. We derived new scaling laws for loop apex temperature and footpoint pressure as functions of loop length, volumetric heating rate and heating scale height.

J. Dudik; E. Dzifcakova; A. Kulinova; M. Karlicky

2008-01-01

303

High hydrostatic pressure inactivation of total aerobic bacteria, lactic acid bacteria, yeasts in sour Chinese cabbage  

Microsoft Academic Search

This study investigated the inactivation of total aerobic bacteria (TAB), lactic acid bacteria (LAB), yeasts in sour Chinese cabbage (SCC) treated by high hydrostatic pressure (HHP). The pressure level ranged from 200 to 600MPa and the treatment time were 10–30min. All samples were stored at 4, 27 and 37°C for 90days. The pressure level of 200MPa had no significant impact

Lin Li; Lun Feng; Junjie Yi; Cheng Hua; Fang Chen; Xiaojun Liao; Zhengfu Wang; Xiaosong Hu

2010-01-01

304

Environmental Constraints on the Mechanics of Crawling and Burrowing Using Hydrostatic Skeletons  

Microsoft Academic Search

Mechanics, kinematics, and energetics of crawling and burrowing by limbless organisms using hydrostatic skeletons depend on\\u000a the medium and mode in which the organism is moving. Whether the animal is moving over or through a solid has long been considered\\u000a important enough to distinguish crawling and burrowing as different terms, and in fact the mechanics are very different. Crawlers\\u000a use

K. M. Dorgan

2010-01-01

305

Effect of hydrostatic pressure on defect structure and durability of ultrafine-grained aluminum  

NASA Astrophysics Data System (ADS)

The influence of hydrostatic pressure on the structure and durability of ultrafine-grained aluminum obtained equal-channel angular pressing (ECAP) has been studied. It is established that the experimentally observed initial growth in the durability of ECAP-processed metal is due to the healing of nanopores, whereas a decrease in this growth with increasing number of passes is caused by the related increase in the fraction of large-angle grain boundaries.

Betekhtin, V. I.; Kadomtsev, A. G.; Skleni?ka, V.; Narykova, M. V.

2011-10-01

306

DAMAGE AND MAGNETIC PARAMETERS OF STEEL AFTER PLASTIC DEFORMATION UNDER HYDROSTATIC PRESSURE  

Microsoft Academic Search

The effect of plastic tensile deformation on changes in density and on magnetic properties was investigated for samples of low-carbon steel under hydrostatic pressure of 0.1 to 500 MPa in a test chamber. It was shown that the parameters of minor magnetic hysteresis loops could be used to indicate the degree of plastic deformation and the deformation-related structural damage of

E. S. Gorkunov; S. V. Smirnov

307

Density Measurement of Tridecane by using Hydrostatic Weighing System at Density Laboratory, NML-SIRIM  

NASA Astrophysics Data System (ADS)

This paper presents the density measurement of tridecane by using hydrostatic weighing system, which is currently practised in Density Laboratory of National Metrology Laboratory (NML), SIRIM Berhad. This system weighed the crystal sphere while the crystal sphere was immersed in the tridecane. The volume and mass in air of the crystal sphere were calibrated at KRISS, Korea. The uncertainties of volume and mass in air of the crystal sphere were 4 ppm and 0.3 ppm respectively.

Nor, Mohd. Fazrul Hisyam Mohd.; Othman, Hafidzah; Abidin, Abd. Rashid Zainal

2009-07-01

308

Salinity effects on the maximum hydrostatic pressure for growth of the marine psychrophilic bacterium, Vibrio marinus  

Microsoft Academic Search

In nondefined basal medium containing 35% synthetic seawater salts Vibrio mchws MP-1 reproduces at hydrostatic pressures of 422 2 13.5 and 280 k 13.5 atm at 8 and 4C; in defined basal medium containing 35% NaCl, these maximums are 422 2 6.8 and 327 k 6.8 atm at 9 and 4C. Decreasing the NaC'l concentration results in a corresponding decrease

DOUGLAS S. PALMER; LAWRENCE J. ALBRIGHT

1970-01-01

309

Plastic buckling of ring-stiffened conical shells under external hydrostatic pressure  

Microsoft Academic Search

The paper describes experimental tests carried out on three ring-stiffened cones that were tested to destruction under external hydrostatic pressure. The cones were carefully machined from EN1A Steel. All three cones failed by plastic non-symmetric bifurcation buckling in a mode commonly known as general instability. In this mode the entire ring-shell combination buckles bodily.The paper also provides a design chart

Carl T. F. Ross; Andrew P. F. Little; Kehinde A. Adeniyi

2005-01-01

310

Hydrostatic constraints on morphological exploitation of light in tall Sequoia sempervirens trees  

Microsoft Academic Search

We studied changes in morphological and physiological characteristics of leaves and shoots along a height gradient in Sequoia\\u000a  sempervirens, the tallest tree species on Earth, to investigate whether morphological and physiological acclimation to the vertical light\\u000a gradient was constrained by hydrostatic limitation in the upper crown. Bulk leaf water potential (?) decreased linearly and\\u000a light availability increased exponentially with increasing

Hiroaki T. Ishii; Gregory M. Jennings; Stephen C. Sillett; George W. Koch

2008-01-01

311

Effect of High Hydrostatic Pressure on Physicochemical and Structural Properties of Rice Starch  

Microsoft Academic Search

Rice starch–water suspension (20%) were subjected to high hydrostatic pressure (HHP) treatment at 120, 240, 360, 480, and\\u000a 600 MPa for 30 min. Polarizing light microscope, scanning electron microscopy (SEM), rapid visco analyzer (RVA), differential\\u000a scanning calorimeter (DSC), and X-ray diffraction were used to investigate the physicochemical and structural changes of starch.\\u000a Microscopy studies showed that the treatment of starch with HHP

Wenhao Li; Yunfei Bai; Saleh A. S. Mousaa; Qing Zhang; Qun Shen

312

Isolation of a gene regulated by hydrostatic pressure in a deep-sea bacterium  

Microsoft Academic Search

BAROPHILIC bacteria inhabit the deep oceans, and the specific functional modifications and regulatory mechanisms which govern adaptation to hydrostatic pressure are beginning to be understood. For example, the rate of production of several proteins by some hydrothermal vent archaebacteria1 and the degree of saturation of membrane lipids in other deep-sea bacteria2-4 have been found to change as a result of

Douglas Bartlett; Miriam Wright; A. Aristides Yayanos; Michael Silverman

1989-01-01

313

Improved efficiency of a non-hydrostatic, unstructured grid, finite volume model  

NASA Astrophysics Data System (ADS)

An efficient depth-integrated non-hydrostatic unstructured grid finite volume model is presented and applied to several test cases, which involve the computation of free surface flows. The model solves the non-linear shallow water equations, with extra non-hydrostatic pressure terms to describe dispersion effects. The efficiency of the model is a major issue when it involves large spatial domains with high resolution meshes. Lumping of the pressure gradient of the horizontal velocities is employed, which reduces the number of non-zero elements in the sparse matrix of the Poisson equation by half. This greatly reduces both the memory requirements and the number of floating point operations required to solve the Poisson equations. In addition, for a model using a collocated grid, both the water surface and the non-hydrostatic pressure need to be defined at the incoming wave boundary. A non-hydrostatic pressure boundary, has been derived based on linear wave theory, that is accompanied with the regular incoming short wave for depth-integrated models. It can serve as a simple way to introduce short incoming waves in models with collocated grids. The model has been validated through several test problems including an oscillating basin, propagation of a solitary wave, wave propagation over a submerged bar, wave refraction and diffraction over an elliptical shoal, as well as solitary wave run-up on a conical island. The model gives good results for all test cases. We show that the lumping of the pressure gradient generates identical results to simulations without lumping, while the execution CPU time is reduced by around 30%, demonstrating a good computational efficiency of the model.

Cui, Haiyang; Pietrzak, J. D.; Stelling, G. S.

2012-09-01

314

Effect of High Hydrostatic Pressure (HHP) Treatment on Physicochemical Properties of Horse Mackerel ( Trachurus trachurus )  

Microsoft Academic Search

The basic objective of this study was to determine the effect of high hydrostatic pressure (HHP; 220, 250 and 330 MPa), holding\\u000a time (5 and 10 min) and temperature (7, 15 and 25 °C) on some quality parameters of horse mackerel such as colour changes,\\u000a thiobarbituric acid (TBA-i) and trimethylamine nitrogen (TMA-N), free amino acid content. HHP increased L\\u000a * values of horse

Nuray Erkan; Gonca Üretener; Hami Alpas; Arif Selçuk; Özkan Özden; Sencer Buzrul

315

Low temperature mechanical properties of 316L type stainless steel after hydrostatic extrusion  

Microsoft Academic Search

316L-type stainless steel is commonly used in fusion devices. Its mechanical properties at cryogenic temperatures, for rolled or forged products possessing a grain size of tens of micrometers have been widely reported. In this paper we present the properties of this steel after multi-pass hydrostatic extrusion (HE), which brought about significant grain refinement to the nanometer scale. Such grain refinement

P. Czarkowski; A. T. Krawczynska; R. Slesinski; T. Brynk; J. Budniak; M. Lewandowska; K. J. Kurzydlowski

2011-01-01

316

Analysis of functionally graded thick truncated cone with finite length under hydrostatic internal pressure  

Microsoft Academic Search

Finite Element Method based on Rayleigh–Ritz energy formulation is applied to obtain the elastic behavior of functionally\\u000a graded thick truncated cone. The cone has finite length, and it is subjected to axisymmetric hydrostatic internal pressure.\\u000a The inner surface of the cone is pure ceramic and the outer surface is pure metal, and the material composition varying continuously\\u000a along its thickness.

Kamran Asemi; Mehdi Akhlaghi; Manouchehr Salehi; Seyed Kasra Hosseini Zad

2011-01-01

317

The influence of hydrostatic pressure on the tensile deformation and fracture of copper  

Microsoft Academic Search

An investigation has been made into the effects of hydrostatic pressures up to 600 MPa on the tensile deformation and fracture\\u000a mechanisms of commercial copper. Fracture occurred by the normal tensile fracture mechanism involving void coalescence followed\\u000a by shear tearing at pressures up to 300 MPa. At pressures in excess of 300 MPa fracture occurred entirely by a mechanism involving

Ian E. French; Paul F. Weinrich

1975-01-01

318

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

SciTech Connect

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{sub Sun} and a mean number density of 2.0 {+-} 1.6 Multiplication-Sign 10{sup 7} cm{sup -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{sup -1}), shows a jet-like morphology (opening semi-angles {approx}8 Degree-Sign 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.

Dunham, Michael M.; Chen Xuepeng; Arce, Hector G. [Department of Astronomy, Yale University, P.O. Box 208101, New Haven, CT 06520 (United States); Bourke, Tyler L. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Schnee, Scott [National Radio Astronomy Observatory, 520 Edgemont Road, Charlottesville, VA 22903 (United States); Enoch, Melissa L., E-mail: michael.dunham@yale.edu [Department of Astronomy, University of California at Berkeley, 601 Campbell Hall, Berkeley, CA 94720 (United States)

2011-11-20

319

Effect of hydrostatic extrusion on passivity breakdown on 303 austenitic stainless steel in chloride solution  

Microsoft Academic Search

The stability of the passive film formed on austenitic 303 stainless steel in the as-received state and after severe plastic\\u000a deformation by hydrostatic extrusion (HE) leading to nanostructurization was investigated in an aggressive environment containing\\u000a Cl? ions by anodic polarization. Transmission electron microscopy (TEM) and stereological image analysis were used to examine\\u000a structural changes introduced by HE. Surface analytical techniques

M. Pisarek; P. K?dzierzawski; M. Janik-Czachor; K. J. Kurzyd?owski

2009-01-01

320

Regulation of gene expression in intervertebral disc cells by low and high hydrostatic pressure  

Microsoft Academic Search

Intervertebral disc structures are exposed to wide ranges of intradiscal hydrostatic pressure during different loading excercises\\u000a and are at their minimum during lying or relaxed sitting and at maximum during lifting weights with a round back. We hypothesize\\u000a that these different loading magnitudes influence the intervertebral disc (IVD) by alteration of disc matrix turnover depending\\u000a on their magnitudes. Therefore the

Cornelia Neidlinger-Wilke; Karin Würtz; Jill P. G. Urban; Wolfgang Börm; Markus Arand; Anita Ignatius; Hans-Joachim Wilke; Lutz E. Claes

2006-01-01

321

Density Measurement of Tridecane by using Hydrostatic Weighing System at Density Laboratory, NML-SIRIM  

SciTech Connect

This paper presents the density measurement of tridecane by using hydrostatic weighing system, which is currently practised in Density Laboratory of National Metrology Laboratory (NML), SIRIM Berhad. This system weighed the crystal sphere while the crystal sphere was immersed in the tridecane. The volume and mass in air of the crystal sphere were calibrated at KRISS, Korea. The uncertainties of volume and mass in air of the crystal sphere were 4 ppm and 0.3 ppm respectively.

Nor, Mohd. Fazrul Hisyam Mohd.; Othman, Hafidzah; Abidin, Abd. Rashid Zainal [National Metrology Laboratory, SIRIM Berhad (Malaysia)

2009-07-07

322

The Effect of Hydrostatic Weighting on the Vertical Temperature Structure of the Solar Corona.  

PubMed

We investigate the effect of hydrostatic scale heights lambda(T) in coronal loops on the determination of the vertical temperature structure T&parl0;h&parr0; of the solar corona. Every method that determines an average temperature at a particular line of sight from optically thin emission (e.g., in EUV or soft X-ray wavelengths) of a mutlitemperature plasma is subject to the emission measure-weighted contributions dEM&parl0;T&parr0;&solm0;dT from different temperatures. Because most of the coronal structures (along open or closed field lines) are close to hydrostatic equilibrium, the hydrostatic temperature scale height introduces a height-dependent weighting function that causes a systematic bias in the determination of the temperature structure T&parl0;h&parr0; as function of altitude h. The net effect is that the averaged temperature seems to increase with altitude, dT&parl0;h&parr0;&solm0;dh>0, even if every coronal loop (of a multitemperature ensemble) is isothermal in itself. We simulate this effect with differential emission measure distributions observed by SERTS for an instrument with a broadband temperature filter such as Yohkoh/Soft X-Ray Telescope and find that the apparent temperature increase due to hydrostatic weighting is of order DeltaT approximately T0h&solm0;r middle dot in circle. We suggest that this effect largely explains the systematic temperature increase in the upper corona reported in recent studies (e.g., by Sturrock et al., Wheatland et al., or Priest et al.), rather than being an intrinsic signature of a coronal heating mechanism. PMID:10829008

Aschwanden; Nitta

2000-05-20

323

Weighing Galaxy Clusters with Gas. I. On the Methods of Computing Hydrostatic Mass Bias  

NASA Astrophysics Data System (ADS)

Mass estimates of galaxy clusters from X-ray and Sunyeav-Zel'dovich observations assume the intracluster gas is in hydrostatic equilibrium with their gravitational potential. However, since galaxy clusters are dynamically active objects whose dynamical states can deviate significantly from the equilibrium configuration, the departure from the hydrostatic equilibrium assumption is one of the largest sources of systematic uncertainties in cluster cosmology. In the literature there have been two methods for computing the hydrostatic mass bias based on the Euler and the modified Jeans equations, respectively, and there has been some confusion about the validity of these two methods. The word "Jeans" was a misnomer, which incorrectly implies that the gas is collisionless. To avoid further confusion, we instead refer these methods as "summation" and "averaging" methods respectively. In this work, we show that these two methods for computing the hydrostatic mass bias are equivalent by demonstrating that the equation used in the second method can be derived from taking spatial averages of the Euler equation. Specifically, we identify the correspondences of individual terms in these two methods mathematically and show that these correspondences are valid to within a few percent level using hydrodynamical simulations of galaxy cluster formation. In addition, we compute the mass bias associated with the acceleration of gas and show that its contribution is small in the virialized regions in the interior of galaxy clusters, but becomes non-negligible in the outskirts of massive galaxy clusters. We discuss future prospects of understanding and characterizing biases in the mass estimate of galaxy clusters using both hydrodynamical simulations and observations and their implications for cluster cosmology.

Lau, Erwin T.; Nagai, Daisuke; Nelson, Kaylea

2013-11-01

324

Response of Bacillus cereus spores to high hydrostatic pressure and moderate heat  

Microsoft Academic Search

The effects of high pressure (400–600MPa) and moderate heat (60–80°C) treatments at various process times (10–20min) on the reduction of Bacillus cereus As 1.1846 spores, suspended in milk buffer were investigated. In the present work, response surface methodology (RSM) was employed, and a quadratic equation of high hydrostatic pressure inactivation was built with RSM. By analyzing response surface plots and

Xing-Rong Ju; Yu-Long Gao; Ming-Lan Yao; Yi Qian

2008-01-01

325

Determination of the long-term hydrostatic strength of multilayer pipes  

Microsoft Academic Search

In this paper, a new methodology for prediction of the long-term (creep rupture) behavior of multilayer pipes under internal hydrostatic pressure is presented. For this purpose, a procedure using the three dimensional theory of thick-walled multilayer pipes together with a combined quadratic\\/linear regression analysis is used. The theory of thick walled tubes is used to assess the role of each

M. Farshad

2005-01-01

326

Application of high hydrostatic pressure processing of food to extracting lycopene from tomato paste waste  

Microsoft Academic Search

The application of high hydrostatic pressure (HHP) processing of food to extracting lycopene from tomato paste waste was studied. Various experimental conditions of HHP processing process, such as solvents (chloroform, 95% ethanol and distilled water), ethanol concentration (45–95%, v\\/v), pressure (100–600 MPa), duration (1–10 min) and solid\\/liquid ratio (1:1 to 1:8 g\\/ml), were investigated to optimize the extraction process. The experimental results of

X. Jun

2006-01-01

327

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

SciTech Connect

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.

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

2009-01-01

328

Hydrostatic-pressure studies of magnetic modes in the far infrared  

Microsoft Academic Search

Measurement of the frequency shifts of far-infrared-active magnetic modes as a function of applied hydrostatic pressure has permitted determination of the variation of the superexchange interaction with interionic spacing in MnO, MnF2, and MnF2:Fe2+. In the pure crystals the antiferromagnetic resonance was used as the probe of the exchange interaction, while in MnF2:Fe2+ observation of a localized magnetic-impurity mode above

K. C. Johnson; A. J. Sievers

1974-01-01

329

Effect of Hydrostatic Pressure on the Dielectric Behavior of Polymer Relaxors  

Microsoft Academic Search

Dielectric response of P(VDF\\/TrFE)(50\\/50) copolymer irradiated with 1 MeV electrons was studied under hydrostatic pressure. Pressure results in a nonlinear shift of the dielectric anomaly towards higher temperatures with the initial slope of the temperature of maximum losses dTm\\/dp = 142 K\\/GPa. The contribution of polar clusters to the pressure behavior of the dielectric response is discussed.

B. HILCZER; E. MARKIEWICZ; C Z. PAWLACZYK; M. SZAFRA?SKI; A. HILCZER

2004-01-01

330

Hydrostatic Pressure and Ionic Strength Effects on the Kinetics of Lysozyme  

Microsoft Academic Search

The kinetics of the reaction catalyzed by egg-white lysozyme from hen eggs (EC 3.2.1.17) was investigated by measurement of the decrease in turbidity of suspensions of dried Micrococcus luteus cells. The substrate and NaCl concentration were varied, as well as the hydrostatic pressure (1-476 atm). A plot of the initial velocity against the reciprocal of the substrate concentration gave straight

Walter M. Neville; Henry Eyring

1972-01-01

331

Stability of finite journal bearings from bearings--linear and nonlinear bearing forces  

NASA Astrophysics Data System (ADS)

The paper investigates the relationship between the stability contour determined from the nonlinear simulation and that from the linear theory. The nonlinear bearing forces are directly obtained from the bearing pressure distribution which is solved from the Reynolds equation at each journal position. It is found that the critical speeds in the case of nonlinear bearing forces are the same as those predicted by the linear theory, although the whirl loci under large dynamic excitations are significantly different from those arising from the linear bearing forces. Typical whirling trajectories under impact excitation, positionperturbation and synchronous unbalance excitations are simulated and presented to explain the stable, critical and unstable phenomena. The whirl displacement signals are also transformed to the frequency domain, and their whirling frequencies are analyzed according to their frequency characteristics.

Tieu, A. K.; Qiu, Z. L.

1995-07-01

332

VALIDITY OF BIOELECTRICAL IMPEDANCE ANALYSIS COMPARED TO HYDROSTATIC WEIGHING IN MEASURING BODY COMPOSITION OF MIDDLE AGED WOMEN  

Microsoft Academic Search

Bennis EA, Fatheree BJ, Mesang JN, Palmer DJ, Tauscheck EL. Validity of Bioelectrical Impedance Analysis compared to Hydrostatic Weighing in Measuring Body Composistion of Middle- Aged Women. Journal of Undergraduate Kinesiology Research 2006;2(1):41-48. Purpose: Two current methods for assessing total percent body fat among individuals are the Tanita Bioelectrical Impedance Analysis (BIA) device and hydrostatic underwater weighing. The purpose of

Elizabeth Bennis; Bobbie Jo Fatheree; Jamie Mesang; David Palmer; Erika Tauscheck

333

The effect of annealing under hydrostatic pressure on the visible photoluminescence from si +-ion implanted SiO 2 films  

Microsoft Academic Search

We have studied the influence of the hydrostatic pressure during annealing on the intensity of the visible photoluminescence (PL) from thermally grown SiO2 films irradiated with Si+ ions. Post-implantation anneals have been carried out in an Ar ambient at temperatures Ta of 400°C and 450°C for 10h and 1130°C for 5h at hydrostatic pressures of 1bar–15kbar. It has been found

I. E Tyschenko; L Rebohle; R. A Yankov; W Skorupa; A Misiuk; G. A Kachurin

1998-01-01

334

Hydrostatic piezoelectric property of composite PbTiO3-P(VDF\\/TeFE) for hydrophone applications  

Microsoft Academic Search

In order to improve hydrostatic piezoelectric sensitivity of flexible piezoelectric composites, Lead Titanate (PbTiO3) piezoelectric ceramics is incorporated because of its greater piezoelectric anisotropy. The composites are prepared by embedding ceramic PbTiO3 particles in a copolymer matrix poly(vinylidene fluoride\\/tetrafluoroethylene) (P(VDF\\/TeFE)). The preparation of these composites and their dielectric and hydrostatic piezoelectric properties are reported in this paper. Their hydrophone applications

Xiaoping Zou; Liangying Zhang; Xi Yao; Likun Wang; Fuxue Zhang

1996-01-01

335

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

SciTech Connect

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.

Brodsky, N.S. [RE/SPEC, Inc., Rapid City, SD (United States)

1994-03-01

336

The effects of hydrostatic pressure on matrix synthesis in articular cartilage  

SciTech Connect

The direct effects of hydrostatic pressure on matrix synthesis in articular cartilage can be studied independently of the other factors that change during loading. We have found that the influence of hydrostatic pressure on incorporation rates of {sup 35}SO{sub 4} and ({sup 3}H)proline into adult bovine articular cartilage slices in vitro depends on the pressure level and on the time at pressure. Pressures in the physiological range (5-15 MPa) applied for 20 s or for 5 min could stimulate tracer incorporation (30-130%) during the following 2 h, but higher pressures (20-50 MPa) had no effect on incorporation rates. The degree of stimulation in cartilage obtained from different animals was found to vary; in some animals none was seen. Stimulation also varied with position along the joint. Physiological pressures (5-10 MPa) applied continuously for the 2-h incubation period also stimulated incorporation rates, but pressures greater than 20 MPa always produced a decrease that was related to the applied pressure and that was reversible. These results suggests that the hydrostatic pressure that occurs during loading is a signal that can stimulate matrix synthesis rates in articular cartilage.

Hall, A.C.; Urban, J.P.; Gehl, K.A. (University Laboratory of Physiology, Oxford (England))

1991-01-01

337

A hydrostatic weighing method using total lung capacity and a small tank.  

PubMed Central

The purpose of this study was to establish the validity and reliability of a hydrostatic weighing method using total lung capacity (measuring vital capacity with a respirometer at the time of weighing) the prone position, and a small oblong tank. The validity of the method was established by comparing the TLC prone (tank) method against three hydrostatic weighing methods administered in a pool. The three methods included residual volume seated, TLC seated and TLC prone. Eighty male and female subjects were underwater weighed using each of the four methods. Validity coefficients for per cent body fat between the TLC prone (tank) method and the RV seated (pool), TLC seated (pool) and TLC prone (pool) methods were .98, .99 and .99, respectively. A randomised complete block ANOVA found significant differences between the RV seated (pool) method and each of the three TLC methods with respect to both body density and per cent body fat. The differences were negligible with respect to HW error. Reliability of the TLC prone (tank) method was established by weighing twenty subjects three different times with ten-minute time intervals between testing. Multiple correlations yielded reliability coefficients for body density and per cent body fat values of .99 and .99, respectively. It was concluded that the TLC prone (tank) method is valid, reliable and a favourable method of hydrostatic weighing.

Warner, J G; Yeater, R; Sherwood, L; Weber, K

1986-01-01

338

Hyporheic flow path response to hydraulic jumps at river steps: Hydrostatic model simulations  

NASA Astrophysics Data System (ADS)

This research examined hydrostatic groundwater model (MODFLOW) predictive adequacy and sensitivity in simulating hyporheic flow paths across a river step with a hydraulic jump. In a companion paper, we used flume and hydrodynamic model analysis to develop a refined conceptual model depicting these flow paths with zones of downwelling and upstream-directed flux below the step. The previous coarse conceptual model predicted uniform downstream-directed upwelling below the step. The hydrostatic model accurately predicted the downwelling and upstream-directed fluxes beneath the wave and jump but failed to predict the plunge pool downwelling, which is driven by dynamic pressures. Sensitivity tests varied riverbed topography and water surface profile geometry for a river with 1% slopes, 10 cm flow depths, and 50-150 cm long jets and jumps. The flow paths below the jet-jump region were driven by hydrostatic pressures and were highly sensitive to water surface profile and riverbed topography parameters. Failure to simulate the hydraulic jump caused errors in hyporheic flow path predictions beneath the jump region (˜1 m long by ˜0.5 m deep). If the jump was poorly parameterized, several meters of riverbed flow paths could be erroneously modeled as pointing upstream. The hyporheic zone may contain a spatial mosaic of aerobic and anaerobic waters regulating nutrient transformations and biologic productivity. Accurate parameterization of hydraulic jumps in hyporheic simulation has the potential to improve predictions and explain heterogeneous subsurface flow paths and associated nutrient patterns and ecosystem functions.

Endreny, T.; Lautz, L.; Siegel, D.

2011-02-01

339

A new numerical calculation method for the characteristics of hydrostatic slide  

NASA Astrophysics Data System (ADS)

In the design and manufacture of the ultra-precision machine tools, hydrostatic slides have been applied frequently, in the state-of-the-art technology. They can provide extremely smooth and accurate motion and positioning. At design stage, the carrying capacity and the stiffness of hydrostatic slide is an important value. But, the traditional calculation method of slide stiffness used in engineering is an approximate solution, the accuracy is low. In this paper, finding an accurate calculation method of slide stiffness is present, to improve modeling accuracy. Reynolds equation is the basic equation of calculating performance of hydrostatic slide, oil film pressure distribution can be obtained by solving the Reynolds equation. But Reynolds equation is a second-order partial differential equations, it is difficult to directly solve the equation using analytic methods. Therefore, a discrete model is developed to solve the problem. A method that has been widely used is finite element analysis (FEA). Matlab PDE Toolbox provides a convenient way to solving the partial differential equations based the FEA. But it can only directly solve the partial differential equations with standard form. It is discussed how to transform the Reynolds equation into elliptic partial differential equation with standard form. Then combined with the specific boundary conditions, obtain the oil film pressure distribution through Matlab PDE toolbox, and then write program to achieve high-precision calculation of carrying capacity and stiffness of the slide.

Hou, Guoan; Sun, Tao; Zhou, Jingbo; Qi, Enbing

2012-10-01

340

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

NASA Astrophysics Data System (ADS)

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.

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

2013-05-01

341

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

SciTech Connect

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 {sub vir}, growing to about 30%-45% at the virial radius, R {sub 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.

Molnar, S. M.; Umetsu, K. [Institute of Astronomy and Astrophysics, Academia Sinica, P.O. Box 23-141, Taipei 106, Taiwan (China); Chiu, I.-N.; Chen, P. [Department of Physics, Institute of Astrophysics, and Center for Theoretical Sciences, National Taiwan University, Taipei 10617, Taiwan (China); Hearn, N. [Computational and Information Systems Laboratory, National Center for Atmospheric Research, P.O. Box 3000, Boulder, CO 80305 (United States); Broadhurst, T. [School of Physics and Astronomy, Tel Aviv University (Israel); Bryan, G.; Shang, C., E-mail: sandor@asiaa.sinica.edu.t [Department of Astronomy, Columbia University, 550 West 120th Street, New York, NY 10027 (United States)

2010-11-20

342

EXPERIMENTAL MEASUREMENT OF PRECISION BEARING DYNAMIC STIFFNESS  

Microsoft Academic Search

Static stiffness measurement of precision bearing components by influence coefficients is complicated by the task of loading and measuring the baseline test fixture stiffness before including the bearing components. Furthermore, as the displacement of the bearing system is measured for various load conditions, the stiffness of high quality bearings may be difficult to distinguish from the test fixture stiffness. The

E. R. Marsh; D. S. Yantek

1997-01-01

343

Magnetic Bearing Sets for a Flywheel System  

Microsoft Academic Search

This paper presents a magnetic bearing set developed to work in a flywheel energy storage system. The bearing set is composed of a permanent magnetic bearing (PMB) and a superconducting magnetic bearing (SMB). A new configuration of a PMB having Nd-Fe-B magnet rings and a back yoke is proposed and compared with an existing one. Finite element method (FEM) simulations

Guilherme Goncalves Sotelo; R. de Andrade; A. C. Ferreira

2007-01-01

344

Hydroinertia gas bearings for micro spinners  

Microsoft Academic Search

Externally pressurized gas bearings with large bearing clearance are successfully used in ultra-high-speed micro spinners. For example, a micro spinner 4 mm in diameter is stably operated at more than 20 krps and its whirl ratio exceeds 20. In such bearings, the inertia effect of the gas flow in bearing clearance becomes predominant and its Mach number exceeds 1. As

Kousuke Hikichi; Satoshi Goto; Shinichi Togo; Shuji Tanaka; Kousuke Isomura

2005-01-01

345

Contact Sensors on Ceramic Ball Bearings  

Microsoft Academic Search

Integration of micro contact sensors onto a ball bearing is a critical technology necessary for on-line bearing health monitoring in an industrial harsh environment and evaluation of the bearing performance and design. The current planner fabrication methods offered by the MEMS technology restrict the possibility of integrating micro sensor onto a double contoured bearing surface in a more traditional manufacturing

Jia Yi; Frederick Just-Agosto; Edwar Romero

2002-01-01

346

Current Status of Hybrid Bearing Damage Detection  

Microsoft Academic Search

Advances in material development and processing have led to the introduction of ceramic hybrid bearings for many applications. The introduction of silicon nitride hybrid bearings into the high-pressure oxidizer turbopump on the space shuttle main engine led NASA to solve a highly persistent and troublesome bearing problem. Hybrid bearings consist of ceramic balls and steel races. The majority of hybrid

PAULA J. DEMPSEY; JOSEPH M. CERTO; WILFREDO MORALES

2005-01-01

347

Reaction Rates in Deformation and Hydrostatic Experiments in the Anhydrous System Anorthite - Forsterite  

NASA Astrophysics Data System (ADS)

The reaction anorthite + forsterite --> cpx + opx + spinel ± gnt proceeds at high temperatures and elevated pressures in the lower crust and upper mantle. This solid-solid reaction was studied experimentally at 900° C in the pressure range of 1000 to 1600 MPa in both shearing deformation and hydrostatic experiments. Powder mixtures (1:1 by vol) of anorthite (An92) and forsterite (Fo93) are hot pressed at 970° C, 750 MPa for 48 hrs in a Griggs apparatus and deformed (? ? = 5 × 105 sec-1) after adjustment of P and T to run conditions. H2O content of the samples has been measured by FTIR and is < 30 ppm. At small pressure overstepping (ca. 200 to 300 MPa) undeformed samples show only 10 % reaction progress after 168 hrs, whereas reaction progress in deformed samples after 72 hrs is 60 %. At greater pressure overstepping (700 to 800 MPa) the difference between deformed and undeformed samples is less pronounced (95 % after 60 hrs deformed, 75 % after 168 hrs undeformed) but still present. At greater pressure overstepping, undeformed samples show an exponential reaction rate, whereas that of deformed samples is always linear. Samples initially deformed and then kept hydrostatically show a fast initial reaction rate (85 % of total reaction progress after 0.25 of total run time), followed by a slower reaction progress (15 % reaction after 0.75 of total time) under hydrostatic conditions. The difference in reaction progress is mainly attributed to different nucleation rates. In all experiments, enstatite rims form around olivine grains separating those from other reaction products. Such coronas are indicative of diffusion-controlled reactions. Plots of rim thickness vs time indicate a relative increase of the bulk diffusion coefficient by a factor 5 in the deformed samples compared to undeformed. However, as the grain size of reaction products of deformed samples is 10 times smaller than in undeformed ones, the nucleation rate in deformed samples is ˜ 5000 times higher. The increased nucleation rate is interpreted to result from higher defect densities and greater driving potential for the reaction in deformed samples. The increased nucleation rate enhances reaction rate and thus rim growth rate, so that a straightforward interpretation of rim growth in terms of diffusion parameters is impossible. Thus, nucleation and length scales of reaction processes in deforming rocks may be very different from those in hydrostatic cases, and for the purpose of extrapolation to nature rates of reaction from hydrostatic experiments provide only minimum values.

Stunitz, H.; de Ronde, A.; Tullis, J.

2004-12-01

348

Modeling of Coronal EUV Loops Observed with TRACE. I. Hydrostatic Solutions with Nonuniform Heating  

NASA Astrophysics Data System (ADS)

Recent observations of coronal loops in EUV wavelengths with the Transition Region and Coronal Explorer (TRACE) and the Extreme-Ultraviolet Imaging Telescope (EIT) on the Solar and Heliospheric Observatory (SOHO) demonstrated three new results that cannot be explained by most of the existing loop models: (1) EUV loops are near-isothermal along their coronal segments, (2) they show an overpressure or overdensity compared with the requirements of steady state loops with uniform heating, and (3) the brightest EUV loops exhibit extended scale heights up to 4 times the hydrostatic scale height. These observations cannot be reconciled with the classical RTV (Rosner, Tucker, & Vaiana) model, they do not support models with uniform heating, and they even partially violate the requirements of hydrostatic equilibrium. In this study we are fitting for the first time steady state solutions of the hydrodynamic equations to observed intensity profiles, permitting a detailed consistency test of the observed temperature T(s) and density profiles ne(s) with steady state models, which was not possible in previous studies based on scaling laws. We calculate some 500 hydrostatic solutions, which cover a large parameter space of loop lengths (L~4-300 Mm), of nonuniform heating functions (with heating scale heights in the range of ?H~1-300 Mm), approaching also the limit of uniform heating (?H>>L). The parameter space can be subdivided into three regimes, which contain (1) solutions of stably stratified loops, (2) solutions of unstably stratified loops (in the case of short heating scale heights, ?H,Mm~LMm), and (3) a regime in which we find no numerical solutions (when ?H,Mm<~LMm). Fitting the hydrostatic solutions to 41 EUV loops observed with TRACE (selected by the criterion of detectability over their entire length), we find that only 30% of the loops are consistent with hydrostatic steady state solutions. None of the observed EUV loops is consistent with a uniform heating function while in quasi-steady state. Those loops compatible with a steady state are found to be heated near the footpoints, with a heating scale height of ?H=12+/-5 Mm, covering a fraction ?H/L=0.2+/-0.1 of the loop length. These results support coronal heating mechanisms operating in or near the chromosphere and transition region.

Aschwanden, Markus J.; Schrijver, Carolus J.; Alexander, David

2001-04-01

349

IDENTIFICATION OF SPEED-DEPENDENT BEARING PARAMETERS  

Microsoft Academic Search

Bearing dynamic characteristics have been a major unknown in the modelling and analysis of large turbo-generators. An identification algorithm for bearing dynamic characterization by using unbalance response measurements is developed for multi-degree-of-freedom (m.d.o.f.) flexible rotor-bearing systems. The algorithm identifies the bearing dynamic parameters, consisting of four effective stiffness and four damping coefficients for each bearing, utilizing frequency domain synchronous unbalance

R. TIWARI; A. W. LEES; M. I. FRISWELL

2002-01-01

350

Influence of the bearing number on micro gas bearing system  

Microsoft Academic Search

This paper employs a numerical method combining the differential transformation method and the finite difference method to study the bifurcation behavior of a rigid rotor supported by a micro gas bearing system. The numerical results reveal a complex dynamic behavior comprising periodic, sub-harmonic, and quasi-periodic responses of the rotor center. Furthermore, the results reveal the changes which take place in

Cheng-Chi Wang; Her-Terng Yau; Yen-Liang Yeh; Ming-Jyi Jang; Jing-Fung Lin

2009-01-01

351

Effects of Bearing Cleaning and Lube Environment on Bearing Performance.  

National Technical Information Service (NTIS)

Running torque data of SR6 ball bearings are presented for different temperatures and speeds. The data are discussed in contrast to generally used torque prediction models and point out the need to obtain empirical data in critical applications. Also, the...

P. C. Ward

1995-01-01

352

Redifferentiation of dedifferentiated bovine articular chondrocytes enhanced by cyclic hydrostatic pressure under a gas-controlled system.  

PubMed

Hydrostatic pressure is one of the most frequently used mechanical stimuli in chondrocyte experiments. A variety of hydrostatic pressure loading devices have been used in cartilage cell experiments. However, no gas-controlled system with other than a low pressure load was used up to this time. Hence we used a polyolefin bag from which gas penetration was confirmed. Chondrocytes were extracted from bovine normal knee joint cartilage. After 3 passages, dedifferentiated chondrocytes were applied to form a pellet. These pellets were cultured in chemically defined serum-free medium with ITS+Premix for 3 days. Then 5 MPa of cyclic hydrostatic pressure was applied at 0.5 Hz for 4 h per day for 4 days. Semiquantitative reverse transcriptase-polymerase chain reaction showed a 5-fold increase in the levels of aggrecan mRNA due to cyclic hydrostatic pressure load (p<0.01). Type II collagen mRNA levels were also upregulated 4-fold by a cyclic hydrostatic pressure load (p<0.01). Type I collagen mRNA levels were similarly reduced in the cyclic hydrostatic pressure load group and in the control group. The partial oxygen pressure (PO2) and partial carbon dioxide pressure (PCO2) of the medium in the bag reached equilibrium in 24 h, and no significant change was observed for 3 days afterwards. PO2 and PCO2 were very well controlled. The loaded pellet showed better safranin O/fast green staining than did the control pellet. Metachromatic staining by Alcian blue staining was found to be stronger in the loaded than in the control pellets. The extracellular matrices excretion of loaded pellets was higher than that of control pellets. These results suggest that gas-controlled cyclic hydrostatic pressure enhanced the cartilaginous matrix formation of dedifferentiated cells differentiated in vitro. PMID:17348796

Kawanishi, Makoto; Oura, Atsuhiro; Furukawa, Katsuko; Fukubayashi, Toru; Nakamura, Kozo; Tateishi, Tetsuya; Ushida, Takashi

2007-05-01

353

Bradycardia of the Polar Bear.  

National Technical Information Service (NTIS)

For several years two male polar bears have been studied by long-life implanted physiological radio capsules at the Naval Arctic Research Laboratory, at Point Barrow. A regular measurement has been the resting heart rate; for this we used the lowest heart...

G. E. Folk J. J. Berberich D. K. Sanders

1973-01-01

354

Toxicity of Polar Bear Liver  

Microsoft Academic Search

ACCORDING to information from the Eskimos, and records from Arctic travellers, bad effects may follow the consumption, by men and dogs, of the livers of polar bear, bearded seal, Greenland fox and Eskimo huskies, whereas livers of other Arctic mammals can usually be eaten without injury.

Kaare Rodahl

1949-01-01

355

THE STABILITY OF GAS BEARINGS  

Microsoft Academic Search

In gas bearings involving divergent flow, a rise in pressure along the ; channel due to the Bernouilli effect is superimposed on the pressure drop due to ; viscosity. Under certain conditions this leads to an unstable gas film. A ; preliminary investigation into this effect was made and is presented. (W.L.H.);

1950-01-01

356

Losses of Superconductor Journal Bearing  

NASA Astrophysics Data System (ADS)

A high-temperature superconductor (HTS) journal bearing was studied for rotational loss. Two HTS bearings support the rotor at top and bottom. The rotor weight is 4 kg and the length is about 300 mm. Both the top and bottom bearings have two permanent magnet (PM) rings with an iron pole piece separating them. Each HTS journal bearing is composed of six pieces of superconductor blocks of size 35×25×10 mm. The HTS blocks are encased in a cryochamber through which liquid nitrogen flows. The inner spool of the cryochamber is made from G-10 to reduce eddy current loss, and the rest of the cryochamber is stainless steel. The magnetic field from the PM rings is < 10 mT on the stainless part. The rotational drag was measured over the same speed range at several chamber pressures. Results indicate that a chamber pressure of 0.4 mtorr is sufficiently low to minimize windage loss, and the 10 mT design criterion for the magnetic field on the stainless part of the cryochamber is too high.

Han, Y. H.; Hull, J. R.; Han, S. C.; Jeong, N. H.; Oh, J. M.; Sung, T. H.

2004-06-01

357

Plain Facts About Plain Bearings.  

National Technical Information Service (NTIS)

This citation summarizes a one-page announcement of technology available for utilization. A special report has been prepared as a concise, practical, easy-to-read guide for anyone with an interest in or need for plain bearings. It begins with a brief hist...

1982-01-01

358

Fuzzy Control of Magnetic Bearings.  

National Technical Information Service (NTIS)

The use of an adaptive fuzzy control algorithm implemented on a VLSI chip for the control of a magnetic bearing was considered. The architecture of the adaptive fuzzy controller is similar to that of a neural network. The performance of the fuzzy controll...

J. J. Feeley G. M. Niederauer D. J. Ahlstrom

1991-01-01

359

Superconductor bearings, flywheels and transportation  

Microsoft Academic Search

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

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

2012-01-01

360

Beth Starts Like Brown Bear!  

ERIC Educational Resources Information Center

|Recounts a reading teacher's illuminating experience with a first grader who enjoyed reading Bill Martin's "Brown Bear" books, despite being labeled as dyslexic. Dyslexia is an elusive condition that is biological in origin and distinct from other reading problems. New research shows that reading difficulties, including dyslexia, occur as part of…

Fawcett, Gay

1994-01-01

361

Robust and intelligent bearing estimation  

SciTech Connect

As the monitoring thresholds of global and regional networks are lowered, bearing estimates become more important to the processes which associate (sparse) detections and which locate events. Current methods of estimating bearings from observations by 3-component stations and arrays lack both accuracy and precision. Methods are required which will develop all the precision inherently available in the arrival, determine the measurability of the arrival, provide better estimates of the bias induced by the medium, permit estimates at lower SNRs, and provide physical insight into the effects of the medium on the estimates. Initial efforts have focused on 3-component stations since the precision is poorest there. An intelligent estimation process for 3-component stations has been developed and explored. The method, called SEE for Search, Estimate, and Evaluation, adaptively exploits all the inherent information in the arrival at every step of the process to achieve optimal results. In particular, the approach uses a consistent and robust mathematical framework to define the optimal time-frequency windows on which to make estimates, to make the bearing estimates themselves, and to withdraw metrics helpful in choosing the best estimate(s) or admitting that the bearing is immeasurable. The approach is conceptually superior to current methods, particular those which rely on real values signals. The method has been evaluated to a considerable extent in a seismically active region and has demonstrated remarkable utility by providing not only the best estimates possible but also insight into the physical processes affecting the estimates. It has been shown, for example, that the best frequency at which to make an estimate seldom corresponds to the frequency having the best detection SNR and sometimes the best time interval is not at the onset of the signal. The method is capable of measuring bearing dispersion, thereby withdrawing the bearing bias as a function of frequency. The lowest measurable frequency in the dispersion pattern is often a near error free bearing. These latter features should be helpful in calibrating the stations for frequency dependent biases induced by the earth. Future efforts will enhance the SEE algorithm and will also evaluate it using larger station data sets.

Claassen, J.P.

1998-07-01

362

TOOL ASSEMBLY WITH BI-DIRECTIONAL BEARING  

DOEpatents

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.

Longhurst, G.E.

1961-07-11

363

Observation of a polar bear with rabies.  

PubMed

On 1 November 1989 the first confirmed case of rabies in a polar bear (Ursus maritimus) was encountered by Inuit hunters in the vicinity of Cape Kendall, Southampton Island, Northwest Territories (Canada). The adult male polar bear had posterior paralysis. Rabies was detected by mouse inoculation and a positive immunoperoxidase reaction on spinal cord and Gasserian ganglion from the bear. Histologic lesions in the lumbar region of the spinal cord were consistent with the posterior paralysis. The impact of rabies on the population dynamics of polar bears probably is minimal. Rabies in polar bears constitutes a potential health hazard for polar bear hunters. PMID:2067058

Taylor, M; Elkin, B; Maier, N; Bradley, M

1991-04-01

364

Therapeutic Vaccination against Adjuvant Arthritis Using Autoimmune T Cells Treated with Hydrostatic Pressure  

NASA Astrophysics Data System (ADS)

An ideal treatment for autoimmune diseases would be a nontoxic means of specifically neutralizing the autoreactive lymphocytes responsible for the disease. This goal has been realized in experimental autoimmunity models by immunizing rats or mice against their own autoimmune cells such that the animals generate an immune response specifically repressive to the disease-producing lymphocytes. This maneuver, termed lymphocyte vaccination, was demonstrated to be effective using some, but not all, autoimmune helper T-lymphocyte lines. We now report that T lymphocytes, otherwise incapable of triggering an immune response, can be transformed into effective immunogens by treating the cells in vitro with hydrostatic pressure. Clone A2b, as effector clone that recognized cartilage proteoglycan and caused adjuvant arthritis in Lewis rats, is such a cell. Untreated A2b could not trigger an immune response, but inoculating rats with pressure-treated A2b induced early remission of established adjuvant arthritis as well as resistance to subsequent disease. Specific resistance to arthritis was associated with anti-idiotypic T-cell reactivity to clone A2b and could be transferred from vaccinated rats to naive recipients using donor lymphoid cells. Aggregation of T-lymphocyte membrane components appeared to be important for an immune response because the effects of hydrostatic pressure could be reproduced by treatment of A2b with chemical cross-linkers or with agents disrupting the cytoskeleton. Populations of lymph node cells from antigen-primed rats, when treated with hydrostatic pressure, could also induce suppression of disease. Thus, effective vaccines can be developed without having to isolate the autoimmune T lymphocytes as lines or clones. These results demonstrate that effector T lymphocytes suitably treated may serve as agents for specifically controlling the immune system.

Lider, Ofer; Karin, Nathan; Shinitzky, Meir; Cohen, Irun R.

1987-07-01

365

Synthetic observations of first hydrostatic cores in collapsing low-mass dense cores. II. Simulated ALMA dust emission maps  

NASA Astrophysics Data System (ADS)

Context. First hydrostatic cores are predicted by theories of star formation, but their existence has never been demonstrated convincingly by (sub)millimeter observations. Furthermore, the multiplicity in the early phases of the star formation process is poorly constrained. Aims: The purpose of this paper is twofold. First, we seek to provide predictions for ALMA dust continuum emission maps from early Class 0 objects. Second, we show to what extent ALMA will be able to probe the fragmentation scale in these objects. Methods: Following our companion paper, we post-processed three state-of-the-art radiation-magneto-hydrodynamic 3D adaptive mesh refinement calculations to compute the emanating dust emission maps. We then produced synthetic ALMA observations of the dust thermal continuum from first hydrostatic cores. Results: We present the first synthetic ALMA observations of dust continuum emission from the first hydrostatic cores. We analyze the results given by the different bands and configurations and we discuss for which combinations of the two the first hydrostatic cores would most likely be observed. We also show that observing dust continuum emission with ALMA will help in identifying the physical processes occurring within collapsing dense cores. If the magnetic field is playing a role, the emission pattern will show evidence of a pseudo-disk and even of a magnetically driven outflow, which pure hydrodynamical calculations cannot reproduce. Conclusions: The capabilities of ALMA will enable us to make significant progress towards understanding the fragmentation at the early Class 0 stage and discovering first hydrostatic cores.

Commerçon, B.; Levrier, F.; Maury, A. J.; Henning, Th.; Launhardt, R.

2012-12-01

366

Refractive index changes of a donor impurity in spherical nanostructures: Effects of hydrostatic pressure and temperature  

NASA Astrophysics Data System (ADS)

The effects of hydrostatic pressure and temperature on the linear, nonlinear and total refractive index (RI) changes of a hydrogenic impurity in the center of spherical quantum dot (QD) and quantum anti-dot (QAD) have been investigated. The comparative approach is used for presenting the results of both models. Our numerical results indicate that the RI changes are considerably sensitive to the value of pressure and temperature. It is found that by increasing the pressure and temperature, the RI curves corresponding to QD and QAD are considerably different in shapes and behaviors. Also, our results show that the temperature increasing imposes the opposite effects than the pressure increasing to the both models.

Naimi, Y.

2013-11-01

367

Shape evolution of a core-shell spherical particle under hydrostatic pressure.  

PubMed

The morphological evolution by surface diffusion of a core-shell spherical particle has been investigated theoretically under hydrostatic pressure when the shear modulii of the core and shell are different. A linear stability analysis has demonstrated that depending on the pressure, shear modulii, and radii of both phases, the free surface of the composite particle may be unstable with respect to a shape perturbation. A stability diagram finally emphasizes that the roughness development is favored in the case of a hard shell with a soft core. PMID:22587137

Colin, Jérôme

2012-03-30

368

Hydrostatic Level Sensors as High Precision Ground Motion Instrumentation for Tevatron and Other Energy Frontier Accelerators  

SciTech Connect

Particle accelerators require very tight tolerances on the alignment and stability of their elements: magnets, accelerating cavities, vacuum chambers, etc. In this article we describe the Hydrostatic Level Sensors (HLS) for very low frequency measurements used in a variety of facilities at Fermilab. We present design features of the sensors, outline their technical parameters, describe their test and calibration procedures, discuss different regimes of operation and give few illustrative examples of the experimental data. Detail experimental results of the ground motion measurements with these detectors will be presented in subsequent papers.

Volk, James; Hansen, Sten; Johnson, Todd; Jostlein, Hans; Kiper, Terry; Shiltsev, Vladimir; Chupyra, Andrei; Kondaurov, Mikhail; Medvedko, Anatoly; Parkhomchuk, Vasily; Singatulin, Shavkat

2012-01-01

369

THE EFFECTS OF HIGH HYDROSTATIC PRESSURE ON THE MICROTUBULES OF TETRAHYMENA PYRIFORMIS  

PubMed Central

Exposure of Tetrahymena pyriformis to 7,500 or 10,000 psi of hydrostatic pressure for 2, 5, or 10 min intervals results in a change in cell shape and ciliary activity. Shape changes occur concurrently with a degradation of longitudinal microtubules in a posterior to anterior direction. High pressure also causes a disruption of ciliary activity. Fine structural analysis reveals a breakdown (presumably microtubule depolymerization) of the central ciliary microtubules. The depolymerization begins at the junction of the central ciliary microtubules with the axosome and progresses distally along the ciliary shaft for a distance of about 0.5 µ.

Kennedy, John R.; Zimmerman, Arthur M.

1970-01-01

370

High hydrostatic pressure and the cell membrane: stress response of Saccharomyces cerevisiae.  

PubMed

The brewing and baking yeast Saccharomyces cerevisiae is a useful eukaryotic model of stress response systems whose study could lead to the understanding of stress response mechanisms in other organisms. High hydrostatic pressure (HHP) exerts broad effects upon yeast cells, interfering with cell membranes, cellular architecture, and the processes of polymerization and denaturation of proteins. In this review, we focus on the effect of HHP on the S. cerevisiae cell membrane and describe the main signaling pathways involved in the pressure response. PMID:20233378

Bravim, Fernanda; de Freitas, Jéssica M; Fernandes, A Alberto R; Fernandes, Patricia M B

2010-02-01

371

Effect of hydrostatic pressure on the space charge distribution in power cable materials  

NASA Astrophysics Data System (ADS)

The performance of high-voltage cables with synthetic insulation is highly dependent on the appearance of a space charge under AC or DC stress. The presence of this charge plays a very important role in aging and polymer breakdown phenomena. For submarine power cables, the pressure P for the immersion depth of the cables is now considered. We then study the effect this has on the space charge distribution, as a function of the amplitude of the stressed applied, DC voltage, temperature and hydrostatic pressure. Preliminary results obtained with cross-linked polyethylene are given.

Garros, B.; Santana, J.

1993-06-01

372

Development of a Smart Bicycle Based on a Hydrostatic Automatic Transmission  

NASA Astrophysics Data System (ADS)

This paper develops a newly bicycle concept named smart bicycle (SBIC) with automatic transmission and energy recuperating ability. The SBIC operation is based on a hydrostatic transmission (HST). Several HST designs have been proposed. Moreover, a use of energy converting and storing devices is an optional design for the SBIC to recovery energy during the deceleration or going downhill process, and to support this energy to the hydraulic system during the acceleration or going uphill process. The working efficiency of the bicycle is then increased and could become competitive with the roller-chain technology. Simulations have been carried out to evaluate the working performances of the proposed SBIC concepts.

Truong, Dinh Quang; Ahn, Kyoung Kwan; Khoa, Le Duy; Thinh, Do Hoang

373

Lubrication for high load duplex bearings.  

National Technical Information Service (NTIS)

Three ES and H-compatible lubricants (Environment, Safety and Health) for high load duplex bearing applications were evaluated and compared against trichlorotrifluoroethane (Freon) deposition of low molecular weight polytetrafluoroethylene (PTFE) bearing ...

R. G. Steinhoff

1997-01-01

374

Railcar Roller Bearing Failure Progression Tests.  

National Technical Information Service (NTIS)

This report describes the laboratory endurance test of six railcar roller bearings that had previously suffered physical damage or were otherwise degraded as a result of actual railroad service. Two different onboard impending bearing failure sensors were...

W. D. Waldron

1982-01-01

375

Development of ASTM Precision Bearing Grease Guide.  

National Technical Information Service (NTIS)

Lubricating grease is one of important operational parameter in the rolling bearing applications. Specially, the selection of the lubricating grease for the precision bearing applications is very risky due to many other factors unique to any specific prec...

I. Rhee

2007-01-01

376

Physiological Determinants of Load Bearing Capacity.  

National Technical Information Service (NTIS)

This study identifies some of the physiological determinants of load bearing capacity. Although it is reasonable to assume that maximal aerobic capacity (VO2) is an important determinant of load bearing ability, research implicating the importance of musc...

J. E. Dziados A. I. Damokosh R. P. Mello J. A. Vogel K. L. Farmer

1987-01-01

377

Predation of Svalbard reindeer by polar bears  

Microsoft Academic Search

Polar bears (Ursus maritimus) are believed to be obligate predators on marine mammals, and particularly, on two species of seals. This paper reports on\\u000a observations of polar bears preying (n=7) and scavenging (n=6) on Svalbard reindeer (Rangifer tarandus platyrhyncus). Similar to their closest evolutionary ancestor, the brown bear (U. arctos), polar bears are opportunistic and will prey on ungulates. Reindeer

Andrew E. Derocher; Øystein Wiig; Georg Bangjord

2000-01-01

378

Mercury in polar bears from Alaska  

SciTech Connect

Alaskan polar bear (Ursus maritimus) muscle and liver samples collected in 1972 were analyzed for total mercury. Bears north of Alaska had more mercury than bears west of Alaska. The only difference between young and adult animals was in the northern area where adults had more mercury in liver tissue than young animals. Levels were probably not high enough to be a serious threat to bears.

Lentfer, J.W.; Galster, W.A.

1987-04-01

379

Bears and Pipeline Construction in Alaska  

Microsoft Academic Search

Serious problems were encountered with bears during construction of the 1274-km-long trans-Alaska oil pipelinebetween Prudhoe Bay and Valdez. This multi-billion-dollar project traversed both black bear (Ursus americanus Pallas) and grizzly bear (U. arctos L.) habitat throughout its entire length. Plans for dealing with anticipated problems with bears were often inadequate. Most (71 %) problems occurred north of the Yukon River

ERICH H. FOLLMANN; JOHN L. HECHTEL

380

Performance of a hybrid cylindrical roller bearing  

Microsoft Academic Search

A 206-size hybrid (ceramic\\/steel) cylindrical roller bearing was tested in MIL-L-23699 C oil at several speeds and loads. Heat-generation data was collected and subsequently correlated with bearing-analysis software. Bearing-cage slip data was also collected at various oil-flow rates, oil temperatures, and with both MIL-L-7808 J and MIL-L-23699 C oils. The hybrid bearing was tested in MIL-L-23699 C oil for for

Stephen M. Schrader

1992-01-01

381

Spectral-domain measurement of polarimetric sensitivity of a side-hole fiber to temperature and hydrostatic pressure  

NASA Astrophysics Data System (ADS)

The spectral dependence of the polarimetric sensitivity of a birefringent side-hole fiber to temperature and hydrostatic pressure was measured using a simple experimental setup comprising a broadband source, a polarizer, a birefringent fiber under test, a birefringent delay line, an analyzer and a compact spectrometer. The spectral interferograms, characterized by the equalization wavelength at which spectral interference fringes have the highest visibility (the largest period) due to the zero overall group birefringence, were processed to retrieve the phase as a function of wavelength. First, from the retrieved phase functions corresponding to different temperatures of the fiber under test, the spectral polarimetric sensitivity to temperature was obtained. Second, from the retrieved phase functions corresponding to different hydrostatic pressures in a chamber with the fiber under test, the spectral polarimetric sensitivity to hydrostatic pressure was obtained.

Hlubina, P.; Olszewski, J.; Martynkien, T.; Mergo, P.; Urba?czyk, W.

2013-05-01

382

Effect of chemical pressure, misfit strain and hydrostatic pressure on structural and magnetic behaviors of rare-earth orthochromates.  

PubMed

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. PMID:23995139

Zhao, Hong Jian; Ren, Wei; Chen, Xiang Ming; Bellaiche, L

2013-08-30

383

The hydrostatic pressure and temperature effects on the binding energy of magnetoexcitons in cylindrical quantum well wires  

NASA Astrophysics Data System (ADS)

We have calculated the binding energy for the ground state of a heavy-hole exciton in GaAs/Ga0.7Al0.3As cylindrical quantum well wires (CQWWs) under the action of a hydrostatic pressure, temperature and magnetic field. The calculations are made using variational methods and the effective mass approximation for a finite confinement potential. The hydrostatic pressure, temperature and magnetic field effects can be summarized as follows; excitonic binding energy is a decreasing function of temperature for fixed pressure and magnetic field also is an increasing function of pressure for fixed temperature and magnetic field values depending on the applied pressure range. For larger magnetic field strengths, the binding energies get larger for any hydrostatic pressure and temperature values as expected.

Baser, P.; Karki, H. D.; Demir, I.; Elagoz, S.

2013-11-01

384

Iron reduction and mineralization of deep-sea iron reducing bacterium Shewanella piezotolerans WP3 at elevated hydrostatic pressures.  

PubMed

In this study, iron reduction and concomitant biomineralization of a deep-sea iron reducing bacterium (IRB), Shewanella piezotolerans WP3, were systematically examined at different hydrostatic pressures (0.1, 5, 20, and 50 MPa). Our results indicate that bacterial iron reduction and induced biomineralization are influenced by hydrostatic pressure. Specifically, the iron reduction rate and extent consistently decreases with the increase in hydrostatic pressure. By extrapolation, the iron reduction rate should drop to zero by ~68 MPa, which suggests a possible shut-off of enzymatic iron reduction of WP3 at this pressure. Nano-sized superparamagnetic magnetite minerals are formed under all the experimental pressures; nevertheless, even as magnetite production decreases, the crystallinity and grain size of magnetite minerals increase at higher pressure. These results imply that IRB may play an important role in iron reduction, biomineralization, and biogeochemical cycling in deep-sea environments. PMID:24102974

Wu, W F; Wang, F P; Li, J H; Yang, X W; Xiao, X; Pan, Y X

2013-09-17

385

Design Handbook on Gas Bearings for Gyroscopes.  

National Technical Information Service (NTIS)

This report presents the work accomplished thus far in the preparation of a design handbook on gas bearings for the spin-axis of gyroscopes. The ultimate handbook will contain design data on four different bearings: (1) the spiral-grooved thrust bearing; ...

J. H. Vohr C. Y. Chow

1966-01-01

386

14 CFR 27.623 - Bearing factors.  

Code of Federal Regulations, 2013 CFR

...2013-01-01 2013-01-01 false Bearing factors. 27.623 Section 27.623...Construction General § 27.623 Bearing factors. (a) Except as provided...to pounding or vibration, must have a bearing factor large enough to provide for...

2013-01-01

387

14 CFR 23.623 - Bearing factors.  

Code of Federal Regulations, 2013 CFR

...2013-01-01 2013-01-01 false Bearing factors. 23.623 Section 23.623...Design and Construction § 23.623 Bearing factors. (a) Each part that has...to pounding or vibration, must have a bearing factor large enough to provide for...

2013-01-01

388

14 CFR 29.623 - Bearing factors.  

Code of Federal Regulations, 2013 CFR

...2013-01-01 2013-01-01 false Bearing factors. 29.623 Section 29.623...Construction General § 29.623 Bearing factors. (a) Except as provided...to pounding or vibration, must have a bearing factor large enough to provide for...

2013-01-01

389

14 CFR 25.623 - Bearing factors.  

Code of Federal Regulations, 2013 CFR

...2013-01-01 2013-01-01 false Bearing factors. 25.623 Section 25.623...Construction General § 25.623 Bearing factors. (a) Except as provided...to pounding or vibration, must have a bearing factor large enough to provide for...

2013-01-01

390

49 CFR 229.64 - Plain bearings.  

Code of Federal Regulations, 2012 CFR

... 2012-10-01 2012-10-01 false Plain bearings. 229.64 Section 229.64 Transportation...Requirements Suspension System § 229.64 Plain bearings. A plain bearing box shall contain visible free oil and may not...

2012-10-01

391

49 CFR 229.64 - Plain bearings.  

Code of Federal Regulations, 2011 CFR

... 2011-10-01 2011-10-01 false Plain bearings. 229.64 Section 229.64 Transportation...Requirements Suspension System § 229.64 Plain bearings. A plain bearing box shall contain visible free oil and may not...

2011-10-01

392

49 CFR 229.69 - Side bearings.  

Code of Federal Regulations, 2011 CFR

... Suspension System § 229.69 Side bearings. (a) Friction side bearings with springs designed to carry weight may not...than 25 percent of the springs in any one nest broken. (b) Friction side bearings may not be run in contact unless designed to...

2011-10-01

393

49 CFR 229.69 - Side bearings.  

Code of Federal Regulations, 2012 CFR

... Suspension System § 229.69 Side bearings. (a) Friction side bearings with springs designed to carry weight may not...than 25 percent of the springs in any one nest broken. (b) Friction side bearings may not be run in contact unless designed to...

2012-10-01

394

Teaching American History with Teddy's Bear.  

ERIC Educational Resources Information Center

Discusses the origins of "Teddy's bear," tracing back to a cartoon published in 1902. States that Teddy's bear can shed light on U.S. culture and society. Focuses on the role of Teddy's bear as a symbol of conservationism, an embodiment of male dominance and female nurturance, and a manifestation of white racial supremacy. (CMK)

Forman-Brunell, Miriam

2001-01-01

395

A Spherical Gas Bearing for Airborne Application  

Microsoft Academic Search

A spherical gas bearing is analyzed and tested for an airborne application. The externally pressurized bearing supports an inertially stabilized 36-in aperture, infrared telescope. The bearing provides the isolation of rotary motion from the aircraft and also serves as a seal between the aircraft cabin and cavity condition at 50, 000 ft altitude. The accompanying temperature gradient of 135 F

Anton Bouvier; John C. Schmertz

1975-01-01

396

Stability of high stiffness gas journal bearings  

Microsoft Academic Search

One of the most important problems in the design of gas bearings is their stability. In this paper, results of investigations of the stability of a new type of gas journal bearing, the so-called 'high stiffness bearing' (HSB), are presented. As linear models of HSB do not allow us to estimate the stability threshold with satisfactory precision, all the numerical

Krzysztof Czolczynski

1994-01-01

397

Vibration in Grease Lubricated Bearing Systems  

Microsoft Academic Search

In this study a dynamic bearing apparatus is designed, developed and used to evaluate noise and vibration of bearings lubricated with various greases under different operating conditions. Eight different greases are evaluated for their vibration and noise characteristics. The threshold, kurtosis and mean square methods are used to quantify grease vibration and rank the greases based on their bearing vibration.

Sundar Ramamurthy; Charles M. Krousgrill; Farshid Sadeghi

2000-01-01

398

Superconducting magnetic bearings for energy storage flywheels  

Microsoft Academic Search

We are investigating the use of flywheels for energy storage. Flywheel devices need to be of high efficiency and an important source of losses is the bearings. In addition, the requirement is for the devices to have long lifetimes with minimal or no maintenance. Conventional rolling element bearings can and have been used, but a noncontact bearing, such as a

T. Coombs; A. M. Campbell; R. Storey; R. Weller

1999-01-01

399

Cool Polar Bears: Dabbing on the Texture  

ERIC Educational Resources Information Center

|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.|

O'Connell, Jean

2011-01-01

400

Teaching American History with Teddy's Bear.  

ERIC Educational Resources Information Center

|Discusses the origins of "Teddy's bear," tracing back to a cartoon published in 1902. States that Teddy's bear can shed light on U.S. culture and society. Focuses on the role of Teddy's bear as a symbol of conservationism, an embodiment of male dominance and female nurturance, and a manifestation of white racial supremacy. (CMK)|

Forman-Brunell, Miriam

2001-01-01

401

Cryptosporidiosis in a black bear in Virginia.  

PubMed

Cryptosporidiosis has not been previously reported in black bears in North America, either free-roaming or captive. However, oocysts have been documented in two captive Malayan sun bears (Helarctos malayanus) located in zoological parks in Taiwan. Developmental stages of Cryptosporidium parvum were observed in tissue sections from the small intestine of a black bear cub found dead in Virginia (USA). PMID:10231767

Duncan, R B; Caudell, D; Lindsay, D S; Moll, H D

1999-04-01

402

Gas Bearing Implementation of Small Cryocooler Compressor  

Microsoft Academic Search

In order to reduce the life-cycle cost of systems that use cryocoolers, it is necessary to extend the operating life of the cooler beyond what is currently available for tactical military applications. Several approaches have been used to increase life such as flexure bearing and gas bearing support. It was determined that a gas bearing system offered a novel and

D. T. Kuo; A. S. Loc; M. Hanes

2006-01-01

403

Grease Life Prediction for Sealed Ball Bearings  

Microsoft Academic Search

Sealed ball bearings are used widely for electric motors and automotive components. Appropriate grease is selected for the each application, considering grease life, bearing torque, sound characteristics, etc. Recently, as these components have become progressively more compact, the sealed ball bearings are required to operate at higher temperatures and rotational speeds. In such cases, grease life has become more critical

T. Kawamura; M. Minami; M. Hirata

2001-01-01

404

36 CFR 13.1236 - Bear orientation.  

Code of Federal Regulations, 2010 CFR

...2009-07-01 2009-07-01 false Bear orientation. 13.1236 Section 13...Brooks Camp Developed Area § 13.1236 Bear orientation. All persons visiting the BCDA must receive an NPS-approved Bear Orientation. Failure to receive an...

2009-07-01

405

36 CFR 13.1236 - Bear orientation.  

Code of Federal Regulations, 2010 CFR

...2010-07-01 2010-07-01 false Bear orientation. 13.1236 Section 13...Brooks Camp Developed Area § 13.1236 Bear orientation. All persons visiting the BCDA must receive an NPS-approved Bear Orientation. Failure to receive an...

2010-07-01

406

36 CFR 13.1236 - Bear orientation.  

Code of Federal Regulations, 2013 CFR

...2013-07-01 2013-07-01 false Bear orientation. 13.1236 Section 13...Brooks Camp Developed Area § 13.1236 Bear orientation. All persons visiting the BCDA must receive an NPS-approved Bear Orientation. Failure to receive an...

2013-07-01

407

FIELD TESTS OF POTENTIAL POLAR BEAR REPELLENTS  

Microsoft Academic Search

Field tests of potential repellents were made on free-ranging polar bears (Ursus maritimus) near Churchill, Manitoba, from 11 October through 12 November 1978. Polar bears were attracted to an observation\\/testing area with sardine baits at 11 sites. Commercial dog repellents and household chemicals were tested for their ability to keep bears from visiting baited sites, recorded sounds were tested for

GARY D. MILLER

408

Minimizing electric bearing currents in ASD systems  

Microsoft Academic Search

During recent years, an increase in bearing failures has been seen in ASD-fed electric motors, as well as in gearboxes, and other connected machinery, caused by electric current flow through such bearings. The theories presented in this paper focus on bearing currents in ASDs of the voltage source pulse width modulated (PWM) type, for use with AC induction motors, although

P. J. Link

1999-01-01

409

Non-linear lattice response of Sm oxypnictides to hydrostatic pressure  

NASA Astrophysics Data System (ADS)

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

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

2013-10-01

410

Isolation of a gene regulated by hydrostatic pressure in a deep-sea bacterium.  

PubMed

Barophilic bacteria inhabit the deep oceans, and the specific functional modifications and regulatory mechanisms which govern adaptation to hydrostatic pressure are beginning to be understood. For example, the rate of production of several proteins by some hydrothermal vent archaebacteria and the degree of saturation of membrane lipids in other deep-sea bacteria have been found to change as a result of cultivation at high pressure. We report here the cloning of gene, ompH, which encodes a major pressure-inducible protein of strain SS9, a gram-negative eubacterium isolated from a depth of 2.5 kilometres in the Sulu Sea. Messenger RNA encoded by ompH is expressed when cells are grown at 280 atm but not at 1 atm, indicating that transcription of the ompH gene is controlled by hydrostatic pressure. The function of the OmpH protein in adaptation to high pressure and the use of the ompH gene in studying how bacteria sense and respond to pressure is discussed. PMID:2479840

Bartlett, D; Wright, M; Yayanos, A A; Silverman, M

1989-11-30

411

High hydrostatic pressure at low temperature as a quarantine treatment to improve the quality of fruits.  

PubMed

Application of high hydrostatic pressure has been proposed as an alternative quarantine process for the Mexican fruit fly, Anastrepha ludens Loew (Diptera: Tephritidae), one of the most important insects infesting mangoes, citrus fruits, and other fruits in Mexico and other Latin American countries. The present study was performed to determine the effect of high pressure treatments at 0 degrees C on the survivorship of eggs and larvae of this pest. The effect of time and pressure level at near-freezing temperatures on the egg hatch and survival of larvae is discussed. Eggs and larvae were pressurized at 25, 50, 75, 100, or 150 MPa for 0, 5, 10, or 20 min at 0 degrees C. Hatch was recorded for 1-, 2-, 3-, and 4-day-old pressurized eggs. For pressurized larvae (first, second, and third instars), percentage of survival was registered. Further, third instars were studied for their ability to pupate and develop to adulthood. The results showed that eggs had higher resistance than larvae to pressure. Larvae were not able to resist pressure treatments at 75 MPa for 20 min at 0 degrees C. Treatments at 150 MPa for 20 min at 0 degrees C were needed to destroy all eggs and larvae of A. ludens, indicating that this process might be useful as a quarantine method for infested fruits. However, more studies involving combination of high hydrostatic pressure at low temperature with precooling treatments are needed in order to decrease the pressure level to avoid fruit damage. PMID:19899960

Velazquez, Gonzalo; Candelario, Hugo E; Ramírez, José A; Mangan, Robert L; Loera-Gallardo, Jesús; Vázquez, Manuel

2010-03-01

412

True-slime-mould-inspired hydrostatically coupled oscillator system exhibiting versatile behaviours.  

PubMed

Behavioural diversity is an indispensable attribute of living systems, which makes them intrinsically adaptive and responsive to the demands of a dynamically changing environment. In contrast, conventional engineering approaches struggle to suppress behavioural diversity in artificial systems to reach optimal performance in given environments for desired tasks. The goals of this research include understanding the essential mechanism that endows living systems with behavioural diversity and implementing the mechanism in robots to exhibit adaptive behaviours. For this purpose, we have focused on an amoeba-like unicellular organism: the plasmodium of true slime mould. Despite the absence of a central nervous system, the plasmodium exhibits versatile spatiotemporal oscillatory patterns and switches spontaneously among these patterns. By exploiting this behavioural diversity, it is able to exhibit adaptive behaviour according to the situation encountered. Inspired by this organism, we built a real physical robot using hydrostatically coupled oscillators that produce versatile oscillatory patterns and spontaneous transitions among the patterns. The experimental results show that exploiting physical hydrostatic interplay—the physical dynamics of the robot—allows simple phase oscillators to promote versatile behaviours. The results can contribute to an understanding of how a living system generates versatile and adaptive behaviours with physical interplays among body parts. PMID:23981517

Umedachi, Takuya; Idei, Ryo; Ito, Kentaro; Ishiguro, Akio

2013-09-01

413

Hydrostatic constraints on morphological exploitation of light in tall Sequoia sempervirens trees.  

PubMed

We studied changes in morphological and physiological characteristics of leaves and shoots along a height gradient in Sequoia sempervirens, the tallest tree species on Earth, to investigate whether morphological and physiological acclimation to the vertical light gradient was constrained by hydrostatic limitation in the upper crown. Bulk leaf water potential (Psi) decreased linearly and light availability increased exponentially with increasing height in the crown. During the wet season, Psi was lower in the outer than inner crown. C isotope composition of leaves (delta(13)C) increased with increasing height indicating greater photosynthetic water use efficiency in the upper crown. Leaf and shoot morphology changed continuously with height. In contrast, their relationships with light availability were discontinuous: morphological characteristics did not correspond to increasing light availability above 55-85 m. Mass-based chlorophyll concentration (chl) decreased with increasing height and increasing light availability. In contrast, area-based chl remained constant or increased with increasing height. Mass-based maximum rate of net photosynthesis (P (max)) decreased with increasing height, whereas area-based P (max) reached maximum at 78.4 m and decreased with increasing height thereafter. Mass-based P (max) increased with increasing shoot mass per area (SMA), whereas area-based P (max) was not correlated with SMA in the upper crown. Our results suggest that hydrostatic limitation of morphological development constrains exploitation of light in the upper crown and contributes to reduced photosynthetic rates and, ultimately, reduced height growth at the tops of tall S. sempervirens trees. PMID:18392856

Ishii, Hiroaki T; Jennings, Gregory M; Sillett, Stephen C; Koch, George W

2008-04-08

414

Hydrostatically coupled dielectric elastomer actuators for tactile displays and cutaneous stimulators  

NASA Astrophysics Data System (ADS)

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

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

2010-03-01

415

Bacteriophage performance against Staphylococcus aureus in milk is improved by high hydrostatic pressure treatments.  

PubMed

The combined effect of bacteriophages, vB_SauS-phi-IPLA35 (phiIPLA35) and vB_SauS-phi-IPLA88 (phiIPLA88), and high hydrostatic pressure (HHP) on Staphylococcus aureus Sa9 was evaluated in pasteurized whole milk under a simulated cold chain break, which was simulated by incubation of milk at 25°C for 48 h. Four-hundred MPa was found to be the most suitable pressure to be used in combination with these phages. Two different levels of staphylococcal initial contamination (1×10(4) and 1×10(6) CFU/mL) were tested. A synergistic effect between HHP and phages was observed in both cases. Compared to each single treatment, the combined treatment was able to reduce the initial S. aureus contamination below the detection limit (<10 CFU/mL). Bacteriophage performance in pressurize milk against S. aureus enabled milder hydrostatic pressure treatments, therefore phages can be regarded as a valuable hurdle on minimally processed food. PMID:22525459

Tabla, R; Martínez, B; Rebollo, J E; González, J; Ramírez, M R; Roa, I; Rodríguez, A; García, P

2012-03-28

416

Induction of Oxidative Stress by High Hydrostatic Pressure in Escherichia coli  

PubMed Central

Using leaderless alkaline phosphatase as a probe, it was demonstrated that pressure treatment induces endogenous intracellular oxidative stress in Escherichia coli MG1655. In stationary-phase cells, this oxidative stress increased with the applied pressure at least up to 400 MPa, which is well beyond the pressure at which the cells started to become inactivated (200 MPa). In exponential-phase cells, in contrast, oxidative stress increased with pressure treatment up to 150 MPa and then decreased again, together with the cell counts. Anaerobic incubation after pressure treatment significantly supported the recovery of MG1655, while mutants with increased intrinsic sensitivity toward oxidative stress (katE, katF, oxyR, sodAB, and soxS) were found to be more pressure sensitive than wild-type MG1655. Furthermore, mild pressure treatment strongly sensitized E. coli toward t-butylhydroperoxide and the superoxide generator plumbagin. Finally, previously described pressure-resistant mutants of E. coli MG1655 displayed enhanced resistance toward plumbagin. In one of these mutants, the induction of endogenous oxidative stress upon high hydrostatic pressure treatment was also investigated and found to be much lower than in MG1655. These results suggest that, at least under some conditions, the inactivation of E. coli by high hydrostatic pressure treatment is the consequence of a suicide mechanism involving the induction of an endogenous oxidative burst.

Aertsen, Abram; De Spiegeleer, Philipp; Vanoirbeek, Kristof; Lavilla, Maria; Michiels, Chris W.

2005-01-01

417

Damage in Escherichia coli Cells Treated with a Combination of High Hydrostatic Pressure and Subzero Temperature?  

PubMed Central

The relationship between membrane permeability, changes in ultrastructure, and inactivation in Escherichia coli strain K-12TG1 cells subjected to high hydrostatic pressure treatment at room and subzero temperatures was studied. Propidium iodide staining performed before and after pressure treatment made it possible to distinguish between reversible and irreversible pressure-mediated cell membrane permeabilization. Changes in cell ultrastructure were studied using transmission electron microscopy (TEM), which showed noticeable condensation of nucleoids and aggregation of cytosolic proteins in cells fixed after decompression. A novel technique used to mix fixation reagents with the cell suspension in situ under high hydrostatic pressure (HHP) and subzero-temperature conditions made it possible to show the partial reversibility of pressure-induced nucleoid condensation. However, based on visual examination of TEM micrographs, protein aggregation did not seem to be reversible. Reversible cell membrane permeabilization was noticeable, particularly for HHP treatments at subzero temperature. A correlation between membrane permeabilization and cell inactivation was established, suggesting different mechanisms at room and subzero temperatures. We propose that the inactivation of E. coli cells under combined HHP and subzero temperature occurs mainly during their transiently permeabilized state, whereas HHP inactivation at room temperature is related to a balance of transient and permanent permeabilization. The correlation between TEM results and cell inactivation was not absolute. Further work is required to elucidate the effects of pressure-induced damage on nucleoids and proteins during cell inactivation.

Moussa, Marwen; Perrier-Cornet, Jean-Marie; Gervais, Patrick

2007-01-01

418

Exciton states in GaAs ?-doped systems under magnetic fields and hydrostatic pressure  

NASA Astrophysics Data System (ADS)

Excitons in GaAs n-type ?-doped quantum wells are studied taking into account the effects of externally applied magnetic fields as well as of hydrostatic pressure. The one-dimensional potential profile in both the conduction and valence bands is described including Hartree effects via a Thomas–Fermi-based local density approximation. The allowed uncorrelated energy levels are calculated within the effective mass and envelope function approximations by means of an expansion over an orthogonal set of infinite well eigenfunctions and a variational method is used to obtain the exciton states. The results are presented as functions of the two-dimensional doping concentration and the magnetic field strength for zero and finite values of the hydrostatic pressure. In general, it is found that the exciton binding energy is a decreasing function of the doping-density and an increasing function of the magnetic field intensity. A comparison with recent experiments on exciton-related photoluminescence in n-type ?-doped GaAs is made.

Mora-Ramos, M. E.; Duque, C. A.

2013-04-01

419

Prediction of acid lactic-bacteria growth in turkey ham processed by high hydrostatic pressure  

PubMed Central

High hydrostatic pressure (HHP) has been investigated and industrially applied to extend shelf life of meat-based products. Traditional ham packaged under microaerophilic conditions may sometimes present high lactic acid bacteria population during refrigerated storage, which limits shelf life due to development of unpleasant odor and greenish and sticky appearance. This study aimed at evaluating the shelf life of turkey ham pressurized at 400 MPa for 15 min and stored at 4, 8 and 12 °C, in comparison to the non pressurized product. The lactic acid bacteria population up to 107 CFU/g of product was set as the criteria to determine the limiting shelf life According to such parameter the pressurized sample achieved a commercial viability within 75 days when stored at 4 °C while the control lasted only 45 days. Predictive microbiology using Gompertz and Baranyi and Roberts models fitted well both for the pressurized and control samples. The results indicated that the high hydrostatic pressure treatment greatly increased the turkey ham commercial viability in comparison to the usual length, by slowing down the growth of microorganisms in the product.

Mathias, S.P.; Rosenthal, A.; Gaspar, A.; Aragao, G.M.F.; Slongo-Marcusi, A.

2013-01-01

420

The BEAR Beamline at Elettra  

SciTech Connect

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.

Nannarone, S.; Pasquali, L.; Selvaggi, G. [UdR-INFM Modena, Universita di Modena and Reggio Emilia, Via Vignolese 905, 41100 Modena (Italy); Borgatti, F.; DeLuisa, A.; Doyle, B.P.; Gazzadi, G.C.; Giglia, A.; Finetti, P.; Pedio, M. [TASC-INFM, MM building in Area Science Park, s.s.14 km 163.5, 34012 Basovizza, Trieste (Italy); Mahne, N. [TASC-INFM, Universita di Trieste, Trieste (Italy); Naletto, G.; Pelizzo, M.G.; Tondello, G. [LUXOR-INFM, Universita di Padova, Padua (Italy)

2004-05-12

421

Stability analysis of a disk-spindle supported by a plain journal bearing and pivot bearing  

Microsoft Academic Search

A hydrodynamic bearing is widely used for hard disk drives, and it is better than a ball bearing in terms of vibration suppression, noise reduction and shock resistance. However, its cost to performance ratio should be further improved. In this study we analyzed the stability of a disk-spindle assembly supported by a hydrodynamic plain journal bearing and a pivot bearing

Kyosuke Ono; Seiji Murashita; Hiroshi Yamaura

2005-01-01

422

On the Control of Synchronous Vibration in Rotor\\/Magnetic Bearing Systems Involving Auxiliary Bearing Contact  

Microsoft Academic Search

During the normal operation of rotor\\/magnetic bearing systems, contacts with auxiliary bearings or bushes are avoided. However, auxiliary bearings are required under abnor- mal conditions and in malfunction situations to prevent contact between the rotor and stator laminations. Studies in the open literature deal largely with rotor drop and the requirements of auxiliary bearings design parameters for safe rundown. Rotor

P. S. Keogh; M. O. T. Cole; M. N. Sahinkaya; C. R. Burrows

2004-01-01

423

ON THE DESIGN OF AN ACTIVE AUXILIARY BEARING FOR ROTOR\\/MAGNETIC BEARING SYSTEMS  

Microsoft Academic Search

This paper considers the design of an actively con- trolled auxiliary bearing system for use with mag- netic bearings. During rotor\\/auxiliary bearing con- tact large frictional contact forces can lead to signif- icant thermal stresses. Furthermore, the non-linear nature of the contact can induce unfavourable rotor dynamic behaviour. An active auxiliary bearing ca- pable of reducing the contact forces and

Iain S. Cade; M. Necip Sahinkaya; Cliord R. Burrows; Patrick S. Keogh

424

ADAPTIVE CONTROL OF ACTIVE MAGNETIC BEARINGS TO PREVENT ROTOR-BEARING CONTACT  

Microsoft Academic Search

Active Magnetic Bearing (AMB) systems offer various ad- vantages over conventional bearings but due to their limited force capacity, with high levels of vibrations the rotor may come into contact with retainer bearings. Under conventional PID control, when a rotor comes into contact with its retainer bear- ings it remains in contact, until the rotor is run down and the

Abdul-Hadi G. Abulrub; M. Necip Sahinkaya; Clifford R. Burrows; Patrick S. Keogh

425

Effects of hydrostatic and uniaxial stress on the conductivity of p-type GaN epitaxial layer  

NASA Astrophysics Data System (ADS)

We present experimental results on the dependence of the electrical conductivity of Mg-doped, p-type GaN on hydrostatic pressure and uniaxial stress. The samples were grown by molecular beam epitaxy on sapphire substrates. Hydrostatic pressure over the range studied (0-7 kbar) leads to a relatively small decrease in the conductivity. Uniaxial stress in the basal plane results in strongly increasing conductivity parallel to the stress direction and in weakly decreasing conductivity perpendicular to the stress direction. We relate the observed symmetry of the piezoconductivity to deformation potential induced changes in the band structure near the top of the valence band.

Liu, Y.; Kauser, M. Z.; Nathan, M. I.; Ruden, P. P.; Dabiran, A. M.; Hertog, B.; Chow, P. P.

2002-10-01

426

Hydrostatic stresses and their effect on the macroflow behavior and microfracture mechanism of two-phase alloys  

Microsoft Academic Search

The aspects of the hydrostatic pressure and tension stresses developed as a result of the interaction between hard and soft\\u000a phases to maintain compatibility are represented for two-phase alloys with different microstructures. It has been theoretically\\u000a proved that the stress triaxiality, defined as the ratio of the hydrostatic stress to the effective stress (?\\u000a \\u000a H\\u000a \\u000a \\/?\\u000a \\u000a e\\u000a ), causes hardening

Li Zhonghua; Gu Haicheng

1991-01-01

427

Unstable polar mode and minimum of the dielectric constant in cubic BaSnO3 under hydrostatic pressure  

NASA Astrophysics Data System (ADS)

From first-principles density-functional theory calculations, we show that above a given hydrostatic pressure, an unstable TO mode appears in the cubic perovskite barium stannate (BaSnO3) at ? . Below this critical pressure, we predict an interesting lowering of the dielectric response of this compound due to a change in the sign of this TO mode effective charge. The results are compared to recent calculations on perovskites under high pressure (titanates, zirconates, and niobates), which exhibit a different mechanism at the origin of the soft mode, and to magnesium silicate (MgSiO3) that does not undergo any ferroelectric transition under hydrostatic pressure.

Bévillon, Émile; Geneste, Grégory

2007-06-01

428

Design of double-coated optical fibers to minimize long-term hydrostatic-pressure-induced microbending losses.  

PubMed

The design of double-coated optical fibers to minimize long-term hydrostatic-pressure-induced microbending losses is investigated. Microbending loss in these fibers is dominated by compressive radial stress at the interface between the glass fiber and the primary coating, which is a function of the material properties of the polymeric coatings and their thickness. To minimize long-term hydrostatic-pressure-induced microbending losses, one should decrease the Young's modulus and Poisson ratio of the primary coating but increase the radius, Young's modulus, Poisson ratio, and relaxation time of the secondary coating. Alternatively, the radius and relaxation time of the primary coating have their optimum values. PMID:18033525

Shiue, S T

2001-02-01

429

Neutron scattering study of a quasi-2D spin-1/2 dimer system Piperazinium Hexachlorodicuprate under hydrostatic pressure  

SciTech Connect

We report inelastic neutron scattering study of a quasi-two-dimensional S=1/2 dimer system piperazinium hexachlorodicuprate under hydrostatic pressure. The spin gap {Delta} becomes softened with the increase of the hydrostatic pressure up to P = 9.0 kbar. The observed threefold degenerate triplet excitation at P = 6.0 kbar is consistent with the theoretical prediction and the bandwidth of the dispersion relation is unaffected within the experimental uncertainty. At P = 9.0 kbar the spin gap is reduced to {Delta} = 0.55 meV from {Delta} = 1.0 meV at ambient pressure.

Hong, Tao [ORNL; Stock, C. [NIST Center for Neutron Research (NCRN), Gaithersburg, MD; Cabrera, I. [Johns Hopkins University; Broholm, C. [Johns Hopkins University; Qiu, Y. [National Institute of Standards and Technology (NIST); Leao, J. B. [National Institute of Standards and Technology (NIST); Poulton, S. J. [National Institute of Standards and Technology (NIST); Copley, J.R.D. [National Institute of Standards and Technology (NIST)

2010-01-01

430

Valve assembly having remotely replaceable bearings  

DOEpatents

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.

Johnson, Evan R. (San Diego, CA); Tanner, David E. (Poway, CA)

1980-01-01

431

Gas Bearing Implementation of Small Cryocooler Compressor  

NASA Astrophysics Data System (ADS)

In order to reduce the life-cycle cost of systems that use cryocoolers, it is necessary to extend the operating life of the cooler beyond what is currently available for tactical military applications. Several approaches have been used to increase life such as flexure bearing and gas bearing support. It was determined that a gas bearing system offered a novel and cost effective approach for our products. This paper presents the implementation of a gas bearing system into the miniature cryocooler compressor. The theoretical analyses used to design the gas bearing system will be discussed and empirical data comparing the performance between the baseline and gas bearing coolers will be presented. A life test program is being undertaken to verify the life characteristics of the gas bearing cooler and the results will be summarized and published at a later date.

Kuo, D. T.; Loc, A. S.; Hanes, M.

2006-04-01

432

Lubrication for high load duplex bearings  

SciTech Connect

Three ES and H-compatible lubricants (Environment, Safety and Health) for high load duplex bearing applications were evaluated and compared against trichlorotrifluoroethane (Freon) deposition of low molecular weight polytetrafluoroethylene (PTFE) bearing lubricant extracted from Vydax{trademark}. Vydax is a product manufactured by DuPont consisting of various molecular weights of PTFE suspended in trichlorotrifluoroethane (Freon) which is an ozone-depleting solvent. Bearings with Supercritical CO{sub 2} deposition of PTFE extracted from Vydax AR/IPA, bearings with titanium carbide coated balls, and bearings with diamond-like carbon races and retainers were evaluated. Bearings with Supercritical CO{sub 2} deposition of PTFE from Vydax AR/IPA performed as well as bearings with Freon deposition of PTFE from Freon-based Vydax.

Steinhoff, R.G.

1997-08-01

433

Estimation of body density based on hydrostatic weighing without head submersion in young Japanese adults.  

PubMed

This study examined a method of predicting body density based on hydrostatic weighing without head submersion (HWwithoutHS). Donnelly and Sintek (1984) developed a method to predict body density based on hydrostatic weight without head submersion. This method predicts the difference (D) between HWwithoutHS and hydrostatic weight with head submersion (HWwithHS) from anthropometric variables (head length and head width), and then calculates body density using D as a correction factor. We developed several prediction equations to estimate D based on head anthropometry and differences between the sexes, and compared their prediction accuracy with Donnelly and Sintek's equation. Thirty-two males and 32 females aged 17-26 years participated in the study. Multiple linear regression analysis was performed to obtain the prediction equations, and the systematic errors of their predictions were assessed by Bland-Altman plots. The best prediction equations obtained were: Males: D(g) = -164.12X1 - 125.81X2 - 111.03X3 + 100.66X4 + 6488.63, where X1 = head length (cm), X2 = head circumference (cm), X3 = head breadth (cm), X4 = head thickness (cm) (R = 0.858, R2 = 0.737, adjusted R2 = 0.687, standard error of the estimate = 224.1); Females: D(g) = -156.03X1 - 14.03X2 - 38.45X3 - 8.87X4 + 7852.45, where X1 = head circumference (cm), X2 = body mass (g), X3 = head length (cm), X4 = height (cm) (R = 0.913, R2 = 0.833, adjusted R2 = 0.808, standard error of the estimate = 137.7). The effective predictors in these prediction equations differed from those of Donnelly and Sintek's equation, and head circumference and head length were included in both equations. The prediction accuracy was improved by statistically selecting effective predictors. Since we did not assess cross-validity, the equations cannot be used to generalize to other populations, and further investigation is required. PMID:16608771

Demura, S; Sato, S; Kitabayashi, T

2006-06-01

434

Genes that are involved in high hydrostatic pressure treatments in a Listeria monocytogenes Scott A ctsR deletion mutant  

Technology Transfer Automated Retrieval System (TEKTRAN)

Listeria monocytogenes is a food-borne pathogen of significant threat to public health. High Hydrostatic Pressure (HHP) treatment can be used to control L. monocytogenes in food. The CtsR (class three stress gene repressor) protein negatively regulates the expression of class III heat shock genes....

435

Characterization of discharge waters from natural gas pipeline hydrostatic testing operations. Volume 3. Topical report, January 1989August 1992  

Microsoft Academic Search

Hydrostatic test waters can contain constituents such as oil and grease, iron, petroleum hydrocarbons, trace elements and polynuclear aromatic hydrocarbons. Various state agencies have a full range of permitting requirements for the discharge of the test water, as well as different requirements for compliance sampling and analysis. To the extent the behavior of constituents in the test water and the

J. T. Tallon; J. P. Fillo; F. J. Myerski; G. E. Mesing

1992-01-01

436

PROMETEO: An hydrostatic mesoscale model applied to the simulation of land-sea breeze in the Barcelona area  

Microsoft Academic Search

A recently developed mesoscale meteorological prognostic numerical model is presented. The main characteristics of the model, such as variables used (potential temperature, wind components, Exner pressure), accepted hypothesis and main approximations (Boussinesq, hydrostatic, anelasticity) are detailed, as well as the second order closure method that describe turbulent transport and the parameterization of radiative divergence. Some aspects related to the numerical

Josep Calbó; José M. Baldasano

1995-01-01

437

Effects of high hydrostatic pressure on distribution dynamics of free amino acids in water soaked brown rice grain  

Microsoft Academic Search

High hydrostatic pressure (HP) with approximately below 400 MPa can induce a transformation of food materials to an alternative form, where membrane systems are damaged but certain enzymes are still active. HP treatment of water soaked brown rice grain could modify the mass transfer inside and apparent activities of enzymes, resulting in HP-dependent change of distribution of free amino acids.

T. Shigematsu; M. Hayashi; K. Nakajima; Y. Uno; A. Sakano; M. Murakami; Y. Narahara; S. Ueno; T. Fujii

2010-01-01

438

Hydrostatic Mooring System. Final Technical Report: Main Report plus Appendices A, B, and C. Volume 1 and 2.  

National Technical Information Service (NTIS)

The main conclusions from the work carried out under this contract are: An ordinary seafarer can learn by training on a simulator, to moor large tanker vessels to the Hydrostatic Mooring, safely and quickly, in all weather conditions up to storms generati...

J. Korsgaard

2000-01-01

439

Effect of Hydrostatic Pressure and Electroporation on Bactericidal Efficiency in Combination with Bacteriocins and Lysozyme. Phase I.  

National Technical Information Service (NTIS)

The bactericidal efficiency of ultrahigh hydrostatic pressure (UMP) and pulsed electric field (PEF) were studied in combination with two acteriocins, nisin A and pediocin AcH, and lysozyme. Several Gram-positive and Gram-negative bacterial species and str...

N. Kalchayanand B. Ray A. Sikes C. P. Dunne

1996-01-01

440

Characterization of the effects of hydrostatic extrusion on grain size, surface composition and the corrosion resistance of austenitic stainless steels  

Microsoft Academic Search

Passivity breakdown on austenitic Types 303 and 316 stainless steels in the as-received state, and after heavy plastic deformation by hydrostatic extrusion (HE), was investigated in an aggressive environment containing Cl? ions. Microscopic, surface analytical and electrochemical methods were used to characterize changes in structure and chemistry of the surface of austenitic stainless steels introduced by HE. TEM and stereological

Marcin Pisarek; Piotr K?dzierzawski; Tomasz P?oci?ski; Maria Janik-Czachor; Krzysztof J. Kurzyd?owski

2008-01-01

441

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

NASA Astrophysics Data System (ADS)

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 secondary wave reproduction in some cases) consistency of the numerical modelling results with known stationary linear test solutions. Numerical stability of the developed model is investigated with respect to the reference state choice, modelling dynamics of a stationary front. The horizontally area-mean reference temperature proves to be the optimal stability warrant. The numerical scheme with explicit residual in the vertical forcing term becomes unstable for cross-frontal temperature differences exceeding 30 K. Stability is restored, if the vertical forcing is treated implicitly, which enables to use time steps, comparable with the hydrostatic SISL.

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

2007-10-01

442

The effects of hydrostatic pressure on signal transduction in brain membranes of deep-sea fishes of the genus Coryphaenoides  

Microsoft Academic Search

To investigate the effects of increased hydrostatic pressure on transmembrane signaling in deep-living marine species, the A1 adenosine receptor - inhibitory G protein (Gi) - adenylyl cyclase signaling complex was examined in brain membrane preparations from four teleost fish species of the deep-sea family Macrouridae. The combined depth ranges of the adults of these species, Coryphaenoides armatus, C. cinereus, C.

J. F. Siebenaller

2000-01-01

443

Comparison of Body Composition Measurements using a New Caliper, Two Established Calipers, Hydrostatic Weighing, and BodPod  

Microsoft Academic Search

Purposes: (1) To compare the Lafayette Instruments (LI) skinfold caliper to the Lange (L) and Harpenden (H) calipers using a diverse subject population. (2) To determine the validity of the LI caliper in a subset of subjects by comparing body compositions from skinfold thicknesses to those measured by hydrostatic weighing (HW) and air displacement plethysmography (ADP). (3) To compare measurements

Erin E Talbert; Christiania N Christensen

2009-01-01

444

Potential application of high hydrostatic pressure to eliminate Escherichia coli O157:H7 on alfalfa sprouted seeds  

Microsoft Academic Search

Sprouts eaten raw are increasingly being perceived as hazardous foods as they have been implicated in Escherichia coli O157:H7 outbreaks where the seeds were found to be the likely source of contamination. The objective of our study was to evaluate the potential of using high hydrostatic pressure (HHP) technology for alfalfa seed decontamination. Alfalfa seeds inoculated with a cocktail of

Hudaa Neetoo; Mu Ye; Haiqiang Chen

2008-01-01

445

Hydrostatic pressure pre-treatment affects the protein profile of boar sperm before and after freezing–thawing  

Microsoft Academic Search

A sublethal environmental stress, high-hydrostatic pressure (HHP) was reported to significantly improve the motility, viability and fertility parameters of frozen bull and boar semen. However, the mechanism of how HHP treatment improves survival rates at sperm cryopreservation remains unclear. The purpose of this study was to evaluate the effect of HHP treatment of fresh boar semen on the protein profile

San-Yuan Huang; Csaba Pribenszky; You-Hai Kuo; Shih-Hua Teng; Yu-Hui Chen; Meng-Ting Chung; Yu-Fang Chiu

2009-01-01

446

Inactivation of Alicyclobacillus acidoterrestris vegetative cells in model system, apple, orange and tomato juices by high hydrostatic pressure  

Microsoft Academic Search

The objective of this study is to determine the effect of high hydrostatic pressure (HHP) on inactivation of Alicyclobacillus acidoterrestris vegetative cells in a model system (BAM broth) and in orange, apple and tomato juices. The shelf-life stability of pressurized juices is also studied. In general the viability loss was enhanced significantly as the level of pressure and temperature were

H. Alpas; L. Alma; F. Bozoglu

2003-01-01

447

Turbocharger bearing retention and lubrication system  

SciTech Connect

This patent describes exhausts gas driven turbocharger. It comprises a housing, a shaft within the housing having a longitudinal axis of rotation and a pair of ends, a compressor wheel mounted within the housing on one end of the shaft for rotation therewith, a turbine wheel mounted within the housing on the other end of the shaft for rotation therewith, means for communicating air to the compressor wheel, means for communicating exhaust gas to the turbine wheel to cause the latter to rotate the shaft and the compressor wheel mounted thereon to compress the air communicated to the compressor wheel, and bearing means mounting the shaft for rotation relative to the housing, the bearing means including a bearing outer ring, a bearing inner ring, and ball bearing elements supporting the bearing outer ring on the bearing inner ring, a bearing locating aperture in the bearing outer ring, and an elongated bearing location pin having a longitudinal axis of symmetry extending transversely to the longitudinal axis of the shaft.

Gutknecht, D.A.

1991-12-31

448

COMPARATIVE STUDY OF ADAPTATIONS FOR CONTINUOUS SWIMMING AND HYDROSTATIC EQUILIBRIUM OF SCOMBROID AND XIPHOID FISHES  

Microsoft Academic Search

ABSTRACT Scombroid,fishes swim,continuously,with,pectoral,fins extended,as lifting hydrofoils to counter,their weight,in water. Their gas bladder,is often reduced,or absent. Typical speeds,were,observed,from,seven,species and,compared,with,the speeds,expected,from them,to,maintain,hydrostatic,equilibrium.,The expected,speeds,were,computed,from a model,I developed,using,data,on the,lifting area of extended,pc.:toral fins and,the weight of the fish in water. Lifting areas of· the pectoral,fins were,determined,from,photographs,of dead,fishes. Mass-length relations were,determined,and,converted,to weight,in water,from,data,on water density and fish density. Typical observed,speeds,varied,among,species,from,0.33 to 2.19 lengths\\/sec. Scom­

John J. Magnuson

449

Director-Configurational Transitions around Microbubbles of Hydrostatically Regulated Size in Liquid Crystals  

NASA Astrophysics Data System (ADS)

A high-pressure technique is introduced which allows a continuous variation of the inclusion size in liquid crystal colloids. We use a nematic liquid crystal host into which micrometer-sized gas bubbles are injected. By applying hydrostatic pressures, the diameter of these gas bubbles can be continuously decreased via compression and absorption of gas into the host liquid crystal, so that the director configurations around a single bubble can be investigated as a function of the bubble size. The theoretically predicted transition from a hyperbolic hedgehog to a Saturn-ring configuration, on reduction of the particle size below a certain threshold, is confirmed to occur at the radius of a few micrometers.

Völtz, C.; Maeda, Y.; Tabe, Y.; Yokoyama, H.

2006-12-01

450

Molecular Evolution in the First Hydrostatic Core Phase Adapting Three-Dimensional Radiation Hydrodynamic Simulations  

NASA Astrophysics Data System (ADS)

We investigate the molecular evolution that develops as star formation proceeds from molecular cloud cores to first hydrostatic cores in three spatial dimensions. We perform a radiation hydrodynamic simulation in order to trace fluid parcels, in which molecular evolution is investigated, using a gas-grain chemical network model. The abundances of gaseous molecules in the warm envelope and the outer layer of the first core (T < 500 K) are mainly determined via evaporation of ice mantles, which are formed in a cold era (˜10 K). We find that large organic molecules, such as CH3OH, are associated with the first core (r < 10 AU). This result suggest that first cores and the surrounding warm envelopes could be observed as very compact hot corinos without stellar signatures, and large organic molecules could be useful to trace first cores.

Furuya, K.; Aikawa, Y.; Tomida, K.; Matsumoto, T.; Saigo, K.; Tomisaka, K.; Hersant, F.; Wakelam, V.

2013-10-01

451

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

SciTech Connect

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

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

1981-12-01

452

Determination of the Stellar Parameters of C-rich Hydrostatic Stars from Spectro-Interferometric Observations  

NASA Astrophysics Data System (ADS)

In this contribution we present the results of our recent investigation on the main characteristics and global structure of five mildly pulsating C-rich AGB stars. Infrared spectroscopy (UKIRT/UIST) in the wavelength range between 0.9 and 4 ?m and K-band infrared interferometric data (Palomar Testbed Interferometer) were collected for our sample of objects. The observations are compared with a recent large grid of hydrostatic model atmospheres. After the identification of the main absorption features (CO, C2, HCN, C2H2, CN), we confine the temperature and C/O ratio of the objects with spectroscopic observations. Since low-resolution spectroscopy is not sensitive to changes in mass and log g, we determine these quantities with interferometric observations. Finally, the fundamental parameters obtained for the set of stars are compared with evolutionary tracks of thermally pulsing AGB stars.

Paladini, C.; van Belle, G. T.; Aringer, B.; Hron, J.; Reegen, P.; Lebzelter, T.; Davies, C.

2011-09-01

453

Selective reduction of ketones using water as a hydrogen source under high hydrostatic pressure.  

PubMed

A selective reduction of a broad variety of ketones is described. The method is based on the combination of a Ni-Al alloy and high hydrostatic pressure (HHP, 2.8 kbar) in an aqueous medium. The reaction of the Ni-Al alloy with water provides in situ hydrogen generation and the high pressure ensures that the H(2) formed remains in the solution, thus the C=O reduction readily occurs. The application of the HHP resulted in selective formation of the desired products and the common problem of non-selective overhydrogenation could be avoided. In most cases the reductions resulted in high yields and excellent selectivities without the use of any base. PMID:22868406

Tomin, Anna; Lazarev, Alexander; Bere, Matthew P; Redjeb, Hana; Török, Béla

2012-09-28

454

Electrical resistivity and thermopower of ErCo3 under hydrostatic pressure  

NASA Astrophysics Data System (ADS)

The magnetic state of the Co 3d-electron subsystem of RCo3 compounds (R=rare-earth elements) with the rhombohedral PuNi3-type structure strongly depends on external parameters. In order to clarify the effect of pressure on the magnetic state of the itinerant Co 3d-electrons, we have measured the electrical resistivity and thermopower at temperatures from 2 K to 300 K under hydrostatic pressures up to 2 GPa. Both, ? and S show anomalies at critical temperature of metamagnetic transition Tm. With increasing pressure Tm, determined from the temperature-dependent resistivity and thermopower, decreases and apparently vanishes at P approx 0.7 GPa. The electrical resistivity and thermopower at low temperatures show abrupt changes at P approx 0.7 GPa, indicating a pressure-induced phase transition.

Nakama, T.; Niki, H.; Nakamura, D.; Takaesu, Y.; Hedo, M.; Yagasaki, K.; Uchima, K.; Gratz, E.; Burkov, A. T.

2009-03-01

455

Islet amyloid polypeptide and high hydrostatic pressure: towards an understanding of the fibrillization process  

NASA Astrophysics Data System (ADS)

Type II Diabetes Mellitus is a disease which is characterized by peripheral insulin resistance coupled with a progressive loss of insulin secretion that is associated with a decrease in pancreatic islet ?-cell mass and the deposition of amyloid in the extracellular matrix of ?-cells, which lead to islet cell death. The principal component of the islet amyloid is a pancreatic hormone called islet amyloid polypeptide (IAPP). High-pressure coupled with FT-IR, CD, ThT fluorescence spectroscopic and AFM studies were carried out to reveal information on the aggregation pathway as well as the aggregate structure of IAPP. Our data indicate that IAPP pre-formed fibrils exhibit a strong polymorphism with heterogeneous structures very sensitive to high hydrostatic pressure, indicating a high percentage of ionic and hydrophobic interactions being responsible for the stability the IAPP fibrils.

Lopes, D. H. J.; Smirnovas, V.; Winter, R.

2008-07-01

456

Advanced setup for high-pressure and low-temperature neutron diffraction at hydrostatic conditions  

SciTech Connect

We describe a design of the experimental setup for neutron diffraction studies at low temperatures and hydrostatic pressure. The significant benefit of the setup, compared to the previous methods, is that it makes possible the simultaneous collection of neutrons diffracted at the 30 deg. -150 deg. range with no contamination by the primary scattering from the sample surroundings and without cutting out the incident and diffracted beams. The suggested design is most useful for third-generation time-of-flight diffractometers and constant wavelength instruments. Application of the setup expands the capabilities of high-pressure neutron diffraction, allowing time-resolved kinetics and structural studies, multihistogram Rietveld, and pair distribution function and texture analyses. The high efficiency of the setup was proven for the HIPPO diffractometer at Los Alamos Neutron Science Center under pressures up to 10 kbar and temperatures from 4 to 300 K.

Lokshin, Konstantin A.; Zhao Yusheng [LANSCE-12, Los Alamos National Laboratory, Los Alamos, New Mexico 87544 (United States)

2005-06-15

457

Using the changes in hydrostatic pressure and pulse transit time to measure arterial blood pressure.  

PubMed

The pulse transit time (PTT)-based method has been proposed as a noninvasive and cuffless alternative for monitoring blood pressure (BP). Yet, a major challenge of the technology is to overcome the requirement of individual calibration. In this study, we aim to explore the possibility of using the changes in hydrostatic pressure and PTT for estimating BP without a calibrating procedure. Eight subjects (aged 35+/-15 years) participated in the study and their PTT were recorded during an arm movement exercise. The results of the study found that PTT increases correspondingly with the height of the arm the subjects raised. Moreover, the calculated changes in PTT agree with that derived from the theoretical model using parameter values which were previously reported in literature. To conclude, the cuffless approach presented in this paper is potentially useful for the estimation of arterial BP. PMID:18002460

Poon, Carmen C Y; Zhang, Y T

2007-01-01

458

Distinct responses to mechanical grinding and hydrostatic pressure in luminescent chromism of tetrathiazolylthiophene.  

PubMed

Luminescent mechanochromism has been intensively studied in the past few years. However, the difference in the anisotropic grinding and the isotropic compression is not clearly distinguished in many cases, in spite of the importance of this discrimination for the application of such mechanochromic materials. We now report the distinct luminescent responses of a new organic fluorophore, tetrathiazolylthiophene, to these stresses. The multichromism is achieved over the entire visible region using the single fluorophore. The different mechanisms of a blue shift by grinding crystals and of a red shift under hydrostatic pressure are fully investigated, which includes a high-pressure single-crystal X-ray diffraction analysis. The anisotropic and isotropic modes of mechanical loading suppress and enhance the excimer formation, respectively, in the 3D hydrogen-bond network. PMID:23815169

Nagura, Kazuhiko; Saito, Shohei; Yusa, Hitoshi; Yamawaki, Hiroshi; Fujihisa, Hiroshi; Sato, Hiroyasu; Shimoikeda, Yuichi; Yamaguchi, Shigehiro

2013-07-03

459

New hydrostatic weighing apparatus for auto-density measurement of seven weights  

NASA Astrophysics Data System (ADS)

A new hydrostatic weighing apparatus (HWA) is designed to load the weight of 1 g to 1 kg by using a loading plate which is made of a thin plate accurate in volume and mass. With this apparatus, the density of up to seven weights in the range of 1 g to 1 kg can be automatically measured in sequence. As a result of measurement, the uncertainty of 95% confidence level with k = 2 was 0.18 kg m-3 for 1 kg weight and 56 kg m-3 for 1 g weight. It was possible to measure the density of standard weights so that one can verify the E1 class weights within the maximum allowable error recommended by OIML. It was shown that major contributing factors of this apparatus to the uncertainty are volume of the loading plate, sample reading of the balance and reciprocal sensitivity of the balance.

Chang, Kyung-Ho; Lee, Yong-Jae; Jung, Sang-Duk

2007-05-01

460

Effects of high hydrostatic pressure on the growth and beta-carotene production of Rhodotorula glutinis.  

PubMed

The effects of high hydrostatic pressure (HHP) on the biomass and beta-carotene biosynthesis of Rhodotorula glutinis R68 were studied. After treatment with five repeated cycles at 300 MPa for 15 min, the barotolerant mutant PR68 was obtained. After 72 h of culture, the biomass of mutant PR68 was 21.6 g/l, decreased by 8.5% compared to the parental strain R68, but its beta-carotene production reached 19.4 mg/l, increased by 52.8% compared to the parental strain R68. The result of restriction fragment length polymorphism (RFLP) analysis suggested that mutant strain PR68 was likely to change in nucleic acid level, and thus enhanced beta-carotene production in this strain as a result of gene mutation induced by HHP treatment. PMID:18338316

Wang, Sui-Lou; Chen, De-Jing; Deng, Bai-Wan; Wu, Xiao-Zong

2008-04-01

461

The effect of high hydrostatic pressure on black truffle (tuber melanosporum) flavour compounds  

NASA Astrophysics Data System (ADS)

The effects of high hydrostatic pressure (HHP), at 4°C or -18°C, on black truffle flavour compounds, alteration enzymes (lipoxigenase (LOX), peroxidase (POD) and polyphenoloxidase (PPO)) and microbiological qualities were evaluated. The choosen analytes for this study are six alcohols, three aldehydes, one ketone and on sulfur component. The highest flavour stability was observed when samples were pressurized at 300 MPa / 4°C / 10 min. All the treatments induced a drastic decrease of LOX activity and a slight decrease of POD activity. On the other hand, the PPO was not inactivated by pressurization at sub-zero (200 MPa / -18°C / 10 min) and was strongly increased after the 300 MPa / 4°C / 10 min treatment. Pressurization at 300 and 550 MPa lead to an almost complete Pseudomonas fluorescens reduction (6 and 6.5 log destruction, respectively) whereas pressurization at -18°C (200MPa) allowed to obtain only 3 log reduction.

Verret, C.; Ballestra, P.; Cruz, C.; Pardon, P.; Largeteau, A.; Moueffak, A. H. E.

2008-07-01

462

Hydrostatic pressure effect on photoionization cross section of a trion in quantum dots  

NASA Astrophysics Data System (ADS)

It is known experimentally that stable charged excitons can exist in low-dimensional semiconductor nanostructures. Much less is known about the properties of such charged-exciton complexes since three-body problems are very difficult to solve, even numerically. Here, we use the matrix diagonalization method and compact-density approach to investigate the charged excitons in a two-dimensional parabolic quantum dot. With typical semiconducting GaAs based materials, the photoionization cross section has been examined based on the computed energies and wave functions. We find that the photoionization cross section of charged excitons is strongly affected by the confinement frequency, hydrostatic pressure and temperature of QDs. Our results also show that the photoionization cross section of a negatively charged exciton is larger than that of a positively charged exciton.

Xie, Wenfang

2013-11-01

463

Effect of high hydrostatic pressure on the BK channel in bovine chromaffin cells.  

PubMed Central

The activity of the BK channel of bovine chromaffin cells was studied at high hydrostatic pressure, using inside-out patches in symmetrical KCl solution, Ca2+-free and at V(H) = -60 to -40 mV. Pressure increased the probability of channels being open (900 atm increasing the probability 30-fold), and it increased the minimum number of channels apparent in the patches. The pressure activation of the channel was reversed on decompression. Channel conductance was unaffected. It was shown that pressure did not act by raising the temperature, or by affecting [Ca] or pH, or the order of the membrane bilayer, and it was concluded that pressure most likely acted directly on the channel proteins and/or their modulating reactions.

Macdonald, A G

1997-01-01

464

Initiation of Germination and Inactivation of Bacillus pumilus Spores by Hydrostatic Pressure  

PubMed Central

The effect of hydrostatic pressures as high as 1,700 atm at 25 C on the heat and radiation resistance of Bacillus pumilus spores was studied. Phosphate-buffered spores were more sensitive to compression than spores suspended in distilled water. Measurements of the turbidity of suspensions, the viability, refractility, stainability, dry weight, and respiratory activity of spores, and calcium and dipicolinic acid release were made for different pressures and times. Initiation of germination occurred at pressures exceeding 500 atm and was the prerequisite for inactivation by compression. The rate of initiation increased with increasing pressure at constant temperature. This result is interpreted as a net decrease in the volume of the system during initiation as a result of increased solvation of the spore components.

Clouston, J. G.; Wills, Pamela A.

1969-01-01

465

Suzaku Observations of the Outskirts of A1835: Deviation from Hydrostatic Equilibrium  

NASA Astrophysics Data System (ADS)

We present results of four-pointing Suzaku X-ray observations (total ~200 ks) of the intracluster medium (ICM) in the A1835 galaxy cluster (kT ~ 8 keV, z = 0.253) out to the virial radius (r vir ~ 2.9 Mpc) and beyond. Faint X-ray emission from the ICM out to r vir is detected. The temperature gradually decreases with radius from ~8 keV in the inner region to ~2 keV at r vir. The entropy profile is shown to flatten beyond r 500, in disagreement with the r 1.1 dependence predicted from the accretion shock heating model. The thermal pressure profile in the range 0.3r 500 <~ r <~ r vir agrees well with that obtained from the stacked Sunyaev-Zel'dovich effect observations with the Planck satellite. The hydrostatic mass profile in the cluster outskirts (r 500 <~ r <~ r vir) falls well short of the weak-lensing one derived from Subaru/Suprime-Cam observations, showing an unphysical decrease with radius. The gas mass fraction at r vir defined with the lensing total mass agrees with the cosmic baryon fraction from the Wilkinson Microwave Anisotropy Probe seven-year data. All these results indicate, rather than the gas-clumping effect, that the bulk of the ICM in the cluster outskirts is far from hydrostatic equilibrium and infalling matter retained some of its kinetic energy. Finally, combining with our recent Suzaku and lensing analysis of A1689, a cluster of similar mass, temperature, and redshift, we show that the cluster temperature distribution in the outskirts is significantly correlated with the galaxy density field in the surrounding large-scale environment at (1-2)r vir.

Ichikawa, Kazuya; Matsushita, Kyoko; Okabe, Nobuhiro; Sato, Kosuke; Zhang, Y.-Y.; Finoguenov, A.; Fujita, Yutaka; Fukazawa, Yasushi; Kawaharada, Madoka; Nakazawa, Kazuhiro; Ohashi, Takaya; Ota, Naomi; Takizawa, Motokazu; Tamura, Takayuki; Umetsu, Keiichi

2013-04-01

466

Variation in Resistance to Hydrostatic Pressure among Strains of Food-Borne Pathogens  

PubMed Central

Among food-borne pathogens, some strains could be resistant to hydrostatic pressure treatment. This information is necessary to establish processing parameters to ensure safety of pressure-pasteurized foods (N. Kalchayanand, A. Sikes, C. P. Dunne, and B. Ray, J. Food Prot. 61:425–431, 1998). We studied variation in pressure resistance among strains of Listeria monocytogenes, Staphylococcus aureus, Escherichia coli O157:H7, and Salmonella species at two temperatures of pressurization. Early-stationary-phase cells in 1% peptone solution were pressurized at 345 MPa either for 5 min at 25°C or for 5, 10, or 15 min at 50°C. The viability loss (in log cycles) following pressurization at 25°C ranged from 0.9 to 3.5 among nine L. monocytogenes strains, 0.7 to 7.8 among seven S. aureus strains, 2.8 to 5.6 among six E. coli O157:H7 strains, and 5.5 to 8.3 among six Salmonella strains. The results show that at 25°C some strains of each species are more resistant to pressure than the others. However, when one resistant and one sensitive strain from each species were pressurized at 345 MPa and 50°C, the population of all except the resistant S. aureus strain was reduced by more than 8 log cycles within 5 min. Viability loss of the resistant S. aureus strain was 6.3 log cycles even after 15 min of pressurization. This shows that strains of food-borne pathogens differ in resistance to hydrostatic pressure (345 MPa) at 25°C, but this difference is greatly reduced at 50°C. Pressurization at 50°C, in place of 25°C, will ensure greater safety of foods.

Alpas, H.; Kalchayanand, N.; Bozoglu, F.; Sikes, A.; Dunne, C. P.; Ray, B.

1999-01-01

467

Evolution of dilatancy and permeability in rock salt during hydrostatic compaction and triaxial deformation  

NASA Astrophysics Data System (ADS)

Combined gas permeability and P and S wave velocity measurements were carried out on rock salt samples from the Gorleben salt dome and the Morsleben salt mine under hydrostatic and triaxial loading condions, mostly at room temperature. Permeabilities in the as-received samples vary between 10-16 and 2×10-20 m2. The initial permeability is primarily due to decompaction induced by drilling, core retrieval and sample preparation. Hydrostatic loading gives rise to a marked decrease of permeability and a coeval significant increase of P and S wave velocities due to progressive closure of grain boundary cracks, tending to approach the in situ matrix permeability (<10-20 m2). The pore space sensitivity of P and S wave velocities is used to monitor the in situ state of the microstructure. Their reversals define the boundary in the state of stresses between dilatant and compactive domains (dilatancy boundary). Dilatancy during triaxial deformation of the compacted rock salt samples is found to evolve stress dependent in various stages. The crack initiation stress increases from ˜18 MPa differential stress at 10 MPa confining pressure to ˜30 MPa at confining pressures above ˜70 MPa. Dilatancy is due to the opening of grain boundary and (100) cleavage cracks and depends on the applied confining pressure. The orientation of the open cracks is primarily controlled by the loading geometry system (compression, extension). As a consequence, permeability increases dramatically with progressive dilatancy, followed by a period of plus/minus constant permeability during strain hardening up to 10% axial strain or even more. This suggests that the evolution of permeability is not only a function of dilatancy but also of microcrack linkage. Importantly, the anisotropic crack array within the samples causes a strong directional dependence of permeability.

Popp, Till; Kern, Hartmut; Schulze, Otto

2001-01-01

468

Mechanics of superconducting magnetic bearings  

SciTech Connect

Levitation forces and lateral forces in relation to the gaps in superconducting bearings were measured using a beam-and-camera system. Dynamic magnetic stiffness derived from vibration tests were compared to static magnetic stiffness. The relaxation of magnetic forces as a function of time was measured as well. The behavior of levitation forces at temperatures from 4.2 K to 77 K were studied. A rotor equipped with two superconducting bearings was fabricated and was spun up to 120,000 RPM. The drag torques acting on the rotor were measured at both atmospheric pressure and at a partial vacuum of a few mm Hg. Many high-temperature superconductors of different compositions fabricated through different processing techniques were investigated by measuring the magnetic force-gap relationships. The data indicated that YBa{sub 2}Cu{sub 3}O{sub 7} specimens made of melt-quench process produced the largest magnetic forces obtained in the laboratory so far. Models predicting the magnetic forces between superconductors and externally applied magnetic fields were studied. A numerical scheme based on the magnetization model was developed. The calculated levitation force-gap relationships showed a reasonable agreement with experimental results.

Chang, Peizen.

1991-01-01

469

Static forces in a superconducting magnet bearing  

SciTech Connect

Static levitation forces and stiffnesses in a superconducting bearing consisting of concentric ring magnets and a superconducting YBaCuO ring are investigated. In the field-cooled mode a levitation force of 20 N has been achieved. The axial and radial stiffnesses have values of 15 N/mm and 10 N/mm, respectively. An arrangement with two bearings supporting a high speed shaft is now under development. A possible application of superconducting magnetic bearings is flywheels for energy storage.

Stoye, P.; Fuchs, G. [Institut fuer Festkoerper- und Werkstofforschung, Dresden (Germany); Gawalek, W.; Goernert, P. [Institut fuer Physikalische Hochtechnologie, Jena (Germany); Gladun, A. [Technische Univ., Dresden (Germany)

1995-11-01

470

Superconducting bearings with levitation control configurations  

SciTech Connect

This patent describes a superconducting rotating assembly. It comprises first and second bearing means comprising a material exhibiting superconducting properties; a rotatable member having two extremities aligned along a common axis; magnet means at each extremity; means for maintaining each the bearing means at a temperature where the superconducting properties are manifest; means for rotating the rotatable member; means for sensing the position of the rotatable member relative to each the bearing means; and means for controlling the levitation forces exerted on the rotatable member by each the bearing means.

Flom, Y.; Royston, J.D.

1992-05-26

471

Development of passive superconducting bearings. Phase 3  

NASA Astrophysics Data System (ADS)

This report documents the development of a passive superconducting bearing that is used to levitate relatively heavy rotors. This bearing was used to levitate a 7 lb rotor and spin at speeds of up to 12,000 rpm. The success of this effort indicates that the superconducting bearings have the potential for transition from a mere laboratory curiosity to a functional bearing component in a wider range of practical applications such as cryoturbopumps, miniature cryocoolers, and magnetic refrigerators. In addition, several configurations using superconductors to support loads along a single axis were investigated. The effort was directed to identify a specific configuration that offers a very high stiffness.

Rao, Dantam K.

1993-05-01

472

Ceramic Bearing Development. Silicon Nitride Bearing Balls of Improved Reliability: Thermal Oxidation.  

National Technical Information Service (NTIS)

The major objective of this work was to improve the reliability of silicon nitride bearing balls by means of an optimized thermal oxidation treatment. Previous work had shown that the thermal fracture resistance of silicon nitride bearing balls increased ...

C. B. Burk

1996-01-01

473

Nuclear genomic sequences reveal that polar bears are an old and distinct bear lineage.  

PubMed

Recent studies have shown that the polar bear matriline (mitochondrial DNA) evolved from a brown bear lineage since the late Pleistocene, potentially indicating rapid speciation and adaption to arctic conditions. Here, we present a high-resolution data set from multiple independent loci across the nuclear genomes of a broad sample of polar, brown, and black bears. Bayesian coalescent analyses place polar bears outside the brown bear clade and date the divergence much earlier, in the middle Pleistocene, about 600 (338 to 934) thousand years ago. This provides more time for polar bear evolution and confirms previous suggestions that polar bears carry introgressed brown bear mitochondrial DNA due to past hybridization. Our results highlight that multilocus genomic analyses are crucial for an accurate understanding of evolutionary history. PMID:22517859

Hailer, Frank; Kutschera, Verena E; Hallström, Björn M; Klassert, Denise; Fain, Steven R; Leonard, Jennifer A; Arnason, Ulfur; Janke, Axel

2012-04-20

474

The Study of the Hydrostatic Pressure Effect on the Thermodynamic Properties of the Rochelle Salt NaKC_4H_4O_6\\cdot4H_2O  

NASA Astrophysics Data System (ADS)

The effect of hydrostatic pressure on thermodynamic properties of Rs was theoretically considered within the framework of the Mitsui model adjusted by taking into account piezoelectric interaction with the shear strain eps_4. The approach, according to which theory model parameters are linearly dependent on hydrostatic pressure, was proposed for consideration. The calculations were carried out in molecular field approximation. Theoretical results for thermodynamic characteristics were compared to experimental data. Basing on theoretical study, the explanation for discrepancies in experimental data derived by different researchers for static dielectric permittivity of a free crystal was proposed. The increase of saturation polarization due to application of hydrostatic pressure is predicted.

Levitskii, R. R.; Moina, A. P.; Andrusyk, A. Ya.; Slivka, A. G.; Kedyulich, V. M.

475

Remote Detection of Bearing Fatigue Spalls via the Dynamic Response of Bearings on the Same Shaft  

Microsoft Academic Search

Turbine engine bearing failures are the leading mechanical cause of class-A failures. The most common mode of bearing failure in turbine engine applications is fatigue spalling. This paper describes a sensor capable of monitoring multiple bearings on a common shaft for the presence of fatigue spalls. Experimental data is presented demonstrating the ability of a single sensor installed on one

David Tow; Sean Marble

2007-01-01

476

Stability of Finite Journal Bearings–-from Linear and Nonlinear Bearing Forces  

Microsoft Academic Search

This paper investigates the relationship between the stability contour determined from the nonlinear simulation and that from the linear theory. The nonlinear bearing forces are directly obtained from the bearing pressure distribution which is solved from the Reynolds equation at each journal position. It is found that the critical speeds in the case of nonlinear bearing forces are the same

A. K. Tieu; Z. L. Qiu

1995-01-01

477

PERFORMANCE OF SYNCHRONOUS CONTROLLERS FOR ROTOR MAGNETIC BEARING SYSTEMS UNDER RETAINER BEARING CONTACT  

Microsoft Academic Search

Magnetic bearings provide frictionless, non-contact support of rotating machinery, but they have limited force generation capabilities and have to incorporate retainer bearings to protect the rotor and stator laminations if rotor vibration levels become excessive. The usual practice when the contact occurs is to shut down the system. The contact occurrence with retainer bearings is not restricted to power loss

M. N. Sahinkaya; A. G. Abulrub; P. S. Keogh

478

Neutron scattering study of URu2Si2 magnetic properties: from hydrostatic pressure to uniaxial stress  

NASA Astrophysics Data System (ADS)

Since the discovery of the unusual magnetic and superconducting properties of URu2Si2 in 1985 by Palstra [1], this heavy fermion has been extensively studied. A ``Hidden Order'' evidences by bulk properties like specific heat, has been found below T0=17.8K. Neutron scattering in this case is an efficient probe for the study of this compound as large magnetic excitations and an irremovable tiny antiferromagnetic moment are present in this sample. Even though the tiny antiferromagnetic moment aligned along the c-axis at Q0 is only ˜0.01 ?B, the magnetic excitations seem to be associated to a large magnetic moment of ˜ 1 ?B and show two minimums at Q0=(1,0,0) but also at Q1=(0.6,0,0). These magnetic responses have been intensively studied in normal conditions by Broholm [2,3] and our group[4], but also versus magnetic field [5], and more recently under hydrostatic pressure [6]. The result of these experiments seem to indicate that the Hidden Order is linked to the excitation at Q0 and not to the excitation at Q1. We will present the revisited magnetic properties of URu2Si2 under uniaxial stress along the a-axis [7,8]. Both elastic and inelastic contributions have been measured versus the constraints. In the HO state, as the constraint increases, the AF gap excitation at Q0 decreases and the tiny moment increases: it seems also that there is a relation between both parameters. On the other hand, the excitation gap at Q1 is slightly increasing. From our measurement we infer a critical pressure of ˜ 0.33 GPa, with a large increase of the antiferromagnetic moment. This behavior is very similar to results under hydrostatic pressure. Combining hydrostatic pressure, uniaxial stress along the a-axis and neutron Larmor diffraction measurements, that gives the lattice distribution of our URu2Si2 crystal, we conclude that the magnetic exchange integrals are dominated by the lattice parameter a and not the ratio c/a as usually believed. [1] T. T. M. Palstra, et al., Physical Review Letters 55, 2727 (1985).[2] C. Broholm, et al., Physical Review Letters 58, 1467 (1987).[3] C. Broholm, et al., Physical Review B 43, 12809 (1991).[4] F. Bourdarot, et al., Journal of the Physical Society of Japan 79, 064719 (2010).[5] F. Bourdarot, et al., Physical Review Letters 90, 067203 (2003).[6] A. Villaume, et al., Physical Review B 78, 012504 (2008).[7] M. Yokoyama, et al., Physical Review B 72, 214419 (2005).[8] F. Bourdarot, et al., Physical Review B 84, 184430 (2011).

Bourdarot, Frederic

2013-03-01

479

Precision instrumentation for rolling element bearing characterization  

SciTech Connect

This article describes an instrument to measure the error motion of rolling element bearings. This challenge is met by simultaneously satisfying four requirements. First, an axial preload must be applied to seat the rolling elements in the bearing races. Second, one of the races must spin under the influence of an applied torque. Third, rotation of the remaining race must be prevented in a way that leaves the radial, axial/face, and tilt displacements free to move. Finally, the bearing must be fixtured and measured without introducing off-axis loading or other distorting influences. In the design presented here, an air bearing reference spindle with error motion of less than 10 nm rotates the inner race of the bearing under test. Noninfluencing couplings are used to prevent rotation of the bearing outer race and apply an axial preload without distorting the bearing or influencing the measurement. Capacitive displacement sensors with 2 nm resolution target the nonrotating outer race. The error motion measurement repeatability is shown to be less than 25 nm. The article closes with a discussion of how the instrument may be used to gather data with sufficient resolution to accurately estimate the contact angle of deep groove ball bearings.

Marsh, Eric R.; Vigliano, Vincent C.; Weiss, Jeffrey R.; Moerlein, Alex W.; Vallance, R. Ryan [Machine Dynamics Research Laboratory, Pennsylvania State University, 331 Reber Building University Park, Pennsylvania 16802 (United States); Precision Systems Laboratory, George Washington University, 738 Phillips Hall 801 22nd Street, N.W. Washington, D.C., 20052 (United States)

2007-03-15

480

Methods and systems for micro bearings  

DOEpatents

A micro drive assembly may comprise a substrate, a micro shall oriented in-plane with the substrate and at least one micro bearing to support rotation of the micro shaft. The micro shaft and micro bearing may be in or less than the micrometer domain.

Stalford, Harold L.

2012-10-09

481

High temperature corrosion resistant bearing steel development  

Microsoft Academic Search

The aim towards increased power-to-weight ratios and reduced specific fuel consumption in advanced gas turbine engines demands mainshaft bearings that are able to operate under an increasingly severe environment. This environment includes higher temperatures, increased hoop stresses, and more rapid accumulation of stress cycles. In addition, corrosion currently accounts for approximately 30 percent of all bearing rejections during engine overhaul.

E. E. Pfaffenberger; P. Tarrantini

1993-01-01

482

Bearing Assembly for an Electrical Machine.  

National Technical Information Service (NTIS)

The bearing assembly differs from existing ones in that a bushing is fixed onto the shaft of the machine in order to increase sealing reliability. The butt end of the bushing from the side opposite the bearing is conical and mates with the seal. A rotatin...

A. S. Kozharin M. P. Bakumenko M. V. Babai Y. S. Marchuk

1972-01-01

483

Self-Feeding Fluid Film Bearings.  

National Technical Information Service (NTIS)

A concept is proposed for a fluid film bearing retainer (FFBR) which includes the following: (1) a reservoir in which excess lubricating fluid is stored; (2) a means of pumping the stored fluid from the reservoir to the bearing; (3) a seal to prevent loss...

C. H. T. Pan R. L. Smith

1982-01-01

484

Precision instrumentation for rolling element bearing characterization  

Microsoft Academic Search

This article describes an instrument to measure the error motion of rolling element bearings. This challenge is met by simultaneously satisfying four requirements. First, an axial preload must be applied to seat the rolling elements in the bearing races. Second, one of the races must spin under the influence of an applied torque. Third, rotation of the remaining race must

Eric R. Marsh; Vincent C. Vigliano; Jeffrey R. Weiss; Alex W. Moerlein; R. Ryan Vallance

2007-01-01

485

Precision instrumentation for rolling element bearing characterization  

NASA Astrophysics Data System (ADS)

This article describes an instrument to measure the error motion of rolling element bearings. This challenge is met by simultaneously satisfying four requirements. First, an axial preload must be applied to seat the rolling elements in the bearing races. Second, one of the races must spin under the influence of an applied torque. Third, rotation of the remaining race must be prevented in a way that leaves the radial, axial/face, and tilt displacements free to move. Finally, the bearing must be fixtured and measured without introducing off-axis loading or other distorting influences. In the design presented here, an air bearing reference spindle with error motion of less than 10 nm rotates the inner race of the bearing under test. Noninfluencing couplings are used to prevent rotation of the bearing outer race and apply an axial preload without distorting the bearing or influencing the measurement. Capacitive displacement sensors with 2 nm resolution target the nonrotating outer race. The error motion measurement repeatability is shown to be less than 25 nm. The article closes with a discussion of how the instrument may be used to gather data with sufficient resolution to accurately estimate the contact angle of deep groove ball bearings.

Marsh, Eric R.; Vigliano, Vincent C.; Weiss, Jeffrey R.; Moerlein, Alex W.; Vallance, R. Ryan

2007-03-01

486

BLACK BEAR DENNING ECOLOGY IN INTERIOR ALASKA  

Microsoft Academic Search

From 1988 to 1991 we observed the denning activity of 27 radio-collared black bears (Ursus americanus) at 57 dens on the Tanana River Flats, near Fairbanks, Alaska. This is the northernmost population of black bears studied using radio telemetry, and nears the northern extreme of their range. We compared differences in den chronology, morphology, and habitat use, among sex, age,

MARTIN E. SMITH; JOHN L. HECHTEL; ERICH H. FOLLMANN

487

Grease Degradation in Rolling Element Bearings  

Microsoft Academic Search

Grease is degraded during use in rolling element bearings and as a result the lubrication performance can deteriorate. Under severe conditions this can result in lubrication failure and, thus, the grease life will effectively limit the bearing life. At present there is a lack of detailed information regarding the changes that occur in the grease and the way in which

P. M. Cann; J. P. Doner; M. N. Webster; V. Wikstrom

2001-01-01

488

Space-filling bearings in three dimensions.  

PubMed

We present the first space-filling bearing in three dimensions. It is shown that a packing which contains only loops of an even number of spheres can be constructed in a self-similar way and that it can act as a three-dimensional bearing in which spheres can rotate without slip and with negligible torsion friction. PMID:14995378

Baram, R Mahmoodi; Herrmann, H J; Rivier, N

2004-01-30

489

29 CFR of - bearing Animals, or Poultry  

Code of Federal Regulations, 2010 CFR

...2010-07-01 false bearing Animals, or Poultry of Raising of Livestock, Bees, Fur Labor Regulations Relating to Labor (Continued...780.147; §§ 780.152 through 780.157. Raising of Livestock, Bees, Fur-bearing Animals, or...

2010-07-01

490

Further Evidence for Hibernation of Bears.  

National Technical Information Service (NTIS)

In the previous symposia on the Biology of Bears, we presented the argument that three species of bears undergo a form of dormancy which is in several senses more profound than in the typical or classical hibernators, such as woodchucks(Marmota monax) (Fo...

G. E. Folk J. M. Hunt M. A. Folk

1977-01-01

491

Improvement of bearing strength of laminated composites  

Microsoft Academic Search

Carbon fibre reinforced composite structures generally out perform metallic ones, but this is not the case when the structure is loaded in bearing. This work examines several different strategies for improving bearing performance. The first strategy was fibre steering (directed fibre placement). Three different methods were used to determine the trajectories for the steered fibres, referred to as the principal

A. Crosky; D. Kelly; R. Li; X. Legrand; N. Huong; R. Ujjin

2006-01-01

492

Dare to Care for a Grizzly Bear  

NSDL National Science Digital Library

Using the Nature episode “The Good, The Bad and the Grizzly,” students will be able to articulate the complex and competing perspectives on how to best handle the growing bear population, and they will investigate the factors contributing to the destabilization of the bear’s Yellowstone ecosystem.

Wnet

2008-11-18

493

Rotating shaft seal and bearing lubricating apparatus  

Microsoft Academic Search

In accordance with an illustrative embodiment of the present invention, a seal or bearing lubricating system adapted for use in a downhole tool such as a drilling motor includes chamber means packed with grease for lubricating said and\\/or bearing, and centrifugal separator means responsive to rotation of a shaft included in said tool for separating and trapping solid particles suspended

Young

1985-01-01

494

Diffusion of Water with Gummy Bears  

NSDL National Science Digital Library

In this activity, learners investigate the movement of water into and out of a polymer. Learners test the diffusion of water through gummy bears, which are made of sugar and gelatin (a polymer). Learners compare what happens when they put gummy bears are submerged in tap water versus distilled water.

Harris, Mary

2003-01-01

495

Genomic sequencing of Pleistocene cave bears.  

PubMed

Despite the greater information content of genomic DNA, ancient DNA studies have largely been limited to the amplification of mitochondrial sequences. Here we describe metagenomic libraries constructed with unamplified DNA extracted from skeletal remains of two 40,000-year-old extinct cave bears. Analysis of approximately 1 megabase of sequence from each library showed that despite significant microbial contamination, 5.8 and 1.1% of clones contained cave bear inserts, yielding 26,861 base pairs of cave bear genome sequence. Comparison of cave bear and modern bear sequences revealed the evolutionary relationship of these lineages. The metagenomic approach used here establishes the feasibility of ancient DNA genome sequencing programs. PMID:15933159

Noonan, James P; Hofreiter, Michael; Smith, Doug; Priest, James R; Rohland, Nadin; Rabeder, Gernot; Krause, Johannes; Detter, J Chris; Pääbo, Svante; Rubin, Edward M

2005-06-02

496

Flywheel energy storage with superconductor magnetic bearings  

SciTech Connect

A system for storing energy in a flywheel suspended by magnetic levitation in a vacuum vessel is described comprising: a rotatable member having a rotation axis in a central shaft said shaft having first and second magnetic tips formed from permanent magnets on opposite ends thereof, superconductor magnetic bearings, positioned to support said first and second magnetic tips and supported in turn by bearing support means, said superconductor magnetic bearings having a main direction of lift; cooling means in thermal contact with said bearing support means; and energy transfer means, connected to said rotatable member, for transferring energy into and extracting energy from said rotatable member, characterized in that: at least one of said superconducting bearings includes a lifting portion comprising melt-processed, directionally solidified material structure having a crystal structure C-axis oriented parallel to said main direction of lift.

Weinberger, B.R.; Lynds, L. Jr.

1993-06-01