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1

Water cooled static pressure probe  

NASA Technical Reports Server (NTRS)

An improved static pressure probe containing a water cooling mechanism is disclosed. This probe has a hollow interior containing a central coolant tube and multiple individual pressure measurement tubes connected to holes placed on the exterior. Coolant from the central tube symmetrically immerses the interior of the probe, allowing it to sustain high temperature (in the region of 2500 F) supersonic jet flow indefinitely, while still recording accurate pressure data. The coolant exits the probe body by way of a reservoir attached to the aft of the probe. The pressure measurement tubes are joined to a single, larger manifold in the reservoir. This manifold is attached to a pressure transducer that records the average static pressure.

Lagen, Nicholas T. (inventor); Eves, John W. (inventor); Reece, Garland D. (inventor); Geissinger, Steve L. (inventor)

1991-01-01

2

Measurement of static pressure on aircraft  

NASA Technical Reports Server (NTRS)

Existing data on the errors involved in the measurement of static pressure by means of static-pressure tubes and fuselage vents are presented. The errors associated with the various design features of static-pressure tubes are discussed for the condition of zero angle of attack and for the case where the tube is inclined to flow. Errors which result from variations in the configuration of static-pressure vents are also presented. Errors due to the position of a static-pressure tube in the flow field of the airplane are given for locations ahead of the fuselage nose, ahead of the wing tip, and ahead of the vertical tail fin. The errors of static-pressure vents on the fuselage of an airplane are also presented. Various methods of calibrating static-pressure installations in flight are briefly discussed.

Gracey, William

1958-01-01

3

Martian Atmospheric Pressure Static Charge Elimination Tool  

NASA Technical Reports Server (NTRS)

A Martian pressure static charge elimination tool is currently in development in the Electrostatics and Surface Physics Laboratory (ESPL) at NASA's Kennedy Space Center. In standard Earth atmosphere conditions, static charge can be neutralized from an insulating surface using air ionizers. These air ionizers generate ions through corona breakdown. The Martian atmosphere is 7 Torr of mostly carbon dioxide, which makes it inherently difficult to use similar methods as those used for standard atmosphere static elimination tools. An initial prototype has been developed to show feasibility of static charge elimination at low pressure, using corona discharge. A needle point and thin wire loop are used as the corona generating electrodes. A photo of the test apparatus is shown below. Positive and negative high voltage pulses are sent to the needle point. This creates positive and negative ions that can be used for static charge neutralization. In a preliminary test, a floating metal plate was charged to approximately 600 volts under Martian atmospheric conditions. The static elimination tool was enabled and the voltage on the metal plate dropped rapidly to -100 volts. This test data is displayed below. Optimization is necessary to improve the electrostatic balance of the static elimination tool.

Johansen, Michael R.

2014-01-01

4

Static pressure test automatic control system  

NASA Astrophysics Data System (ADS)

This paper describes an automatic control system used for testing pressure transducers and digital pressure devices. The system includes microcomputer, multirange pressure standard model, temperature test box, vacuum air pump, and other test devices. Programs are written in FORTRAN, MACRO language, and dBASE-I. It can automatically complete checking pressure transducers, digital pressure devices and calculating their characteristic values. The system has three advantages: (1) man-machine interaction mode, (2) the modular functional calls, and (3) the data base management. Since the system is used, the working speed and accuracy have been rapidly raised in checking pressure transducers and digital pressure devices.

Chen, Jian

1988-12-01

5

Array Of Probes To Measure Static Pressure And Turbulence  

NASA Technical Reports Server (NTRS)

Shapes and arrangements chosen to emphasize desired components of fluctuating pressures. Arrays of pressure probes designed with cross sections and orifices that impart specified directional responses to dynamic pressures, such that one can extract time-averaged static pressure from measurements.

Rossow, Vernon J.

1994-01-01

6

Behavior of static pressure heads at high speeds  

NASA Technical Reports Server (NTRS)

These tests proved the practicability of static pressure heads at speeds up to 400 km/h (248.5 mph). It weighs 6.5 kg or 2.5 times as much as the old head. The position of the pressure head below the airplane was determined by bearing method at different speeds and for different lengths of suspension. It was established that for the measured speed range a 20 to 24 meter suspension length was sufficient to assure a minimum distance of 6 meters from the airplane without introducing any appreciable errors in the results due to wrong static pressure.

Danielzig, Helmut

1938-01-01

7

Static electrically charged fluids in terms of pressure: general property  

NASA Astrophysics Data System (ADS)

A most general exact solution to the Einstein-Maxwell equations for static charged perfect fluid is sought in terms of pressure. Subsequently, metrics ( e ? and e ? ), matter density and electric intensity are expressible in terms of pressure. Consequently, Pressure is found to be an invertible arbitrary function of ?(= c 1+ c 2 r 2), where c 1 and c 2(?0) are arbitrary constants, and r is the radius of star, i.e. p= p( ?). We present a general solution for charged pressure fluid in terms for ?. We list and discuss some old and new solutions which fall in this category.

Bijalwan, Naveen

2011-07-01

8

Pressure  

NSDL National Science Digital Library

This page contains three Physlets that are able to share data using a connection made by a common superclass, SApplet. The ensemble walls keep track of the change in momentum, i.e., the pressure, during each time step, dt, and provides this data to the DataGraph Physlet and the DataTable Physlet.

Christian, Wolfgang; Belloni, Mario

2008-02-09

9

Pressure responsive seal handles static and dynamic loads  

NASA Technical Reports Server (NTRS)

Ported ball valves are sealed under both static and dynamic load conditions by a line-pressure responsive double-acting seal. The top of the seal engages the ported ball at the outer circumferential edge of the seal upper end, and the bottom of the seal seats on a flat circular land with a continuous wall.

Marsh, H. W.

1965-01-01

10

Radio jet refraction in galactic atmospheres with static pressure gradients  

NASA Technical Reports Server (NTRS)

A theory of double radio sources which have a 'Z' or 'S' morphology is proposed, based on the refraction of radio jets in the extended atmosphere of an elliptical galaxy. The model describes a collimated jet of supersonic material bending self-consistently under the influence of external static pressure gradients. Gravity and magnetic fields are neglected in the simplest case except insofar as they determine the static pressure distribution. The calculation is a straightforward extension of a method used to calculate a ram-pressure model for twin radio trails ('C' morphology). It may also be described as a continuous-jet version of a buoyancy model proposed in 1973. The model has the added virtue of invoking a galactic atmosphere similar to those already indicated by X-ray measurements of some other radio galaxies and by models for the collimation of other radio jets.

Henriksen, R. N.; Vallee, J. P.; Bridle, A. H.

1981-01-01

11

Correction of static pressure on a research aircraft in accelerated flight using differential pressure measurements  

NASA Astrophysics Data System (ADS)

A method is described that estimates the error in the static pressure measurement on an aircraft from differential pressure measurements on the hemispherical surface of a Rosemount model 858AJ air velocity probe mounted on a boom ahead of the aircraft. The theoretical predictions for how the pressure should vary over the surface of the hemisphere, involving an unknown sensitivity parameter, leads to a set of equations that can be solved for the unknowns - angle of attack, angle of sideslip, dynamic pressure and the error in static pressure - if the sensitivity factor can be determined. The sensitivity factor was determined on the University of Wyoming King Air research aircraft by comparisons with the error measured with a carefully designed sonde towed on connecting tubing behind the aircraft - a trailing cone - and the result was shown to have a precision of about ±10 Pa over a wide range of conditions, including various altitudes, power settings, and gear and flap extensions. Under accelerated flight conditions, geometric altitude data from a combined Global Navigation Satellite System (GNSS) and inertial measurement unit (IMU) system are used to estimate acceleration effects on the error, and the algorithm is shown to predict corrections to a precision of better than ±20 Pa under those conditions. Some limiting factors affecting the precision of static pressure measurement on a research aircraft are discussed.

Rodi, A. R.; Leon, D. C.

2012-11-01

12

The effect of static pressure on the inertial cavitation threshold.  

PubMed

The amplitude of the acoustic pressure required to nucleate a gas or vapor bubble in a fluid, and to have that bubble undergo an inertial collapse, is termed the inertial cavitation threshold. The magnitude of the inertial cavitation threshold is typically limited by mechanisms other than homogeneous nucleation such that the theoretical maximum is never achieved. However, the onset of inertial cavitation can be suppressed by increasing the static pressure of the fluid. The inertial cavitation threshold was measured in ultrapure water at static pressures up to 30 MPa (300 bars) by exciting a radially symmetric standing wave field in a spherical resonator driven at a resonant frequency of 25.5 kHz. The threshold was found to increase linearly with the static pressure; an exponentially decaying temperature dependence was also found. The nature and properties of the nucleating mechanisms were investigated by comparing the measured thresholds to an independent analysis of the particulate content and available models for nucleation. PMID:22894195

Bader, Kenneth B; Raymond, Jason L; Mobley, Joel; Church, Charles C; Felipe Gaitan, D

2012-08-01

13

Static and dynamic high pressure experiments on cerium  

SciTech Connect

There is a scientific need to obtain dynamic data to develop and validate multi phase equation-of-state (EOS) models for metals. Experiments are needed to examine the relevant pure phases, to locate phase boundaries and the associated transition kinetics, and other material properties such as strength. Cerium is an ideal material for such work because it exhibits a complex multiphase diagram at relatively moderate pressures readily accessible using standard shock wave methods. In the current work, shock wave (dynamic) and diamond anvil cell (static) experiments were performed to examine the high pressure, low temperature region of the phase diagram to obtain EOS data and to search for the {alpha}-{var_epsilon} boundary. Past work examining the shock-melt transition and the low-pressure {gamma}-{alpha} transition will be presented in brief followed by details of recent results obtained from DAC and double-shock experiments.

Jensen, Brian J [Los Alamos National Laboratory; Velisavljevic, Nenad [Los Alamos National Laboratory; Cherne, Frank J [Los Alamos National Laboratory; Stevens, Gerald [NST, STL; Tschauner, Oliver [UNIV OF NEVADA

2011-01-25

14

Plume diagnostics of SRM static firings for pressure perturbation studies  

NASA Technical Reports Server (NTRS)

During the shuttle launches, the solid rocket motors (SRM) occasionally experience pressure perturbations (8-13 psi) between 65 and 75 seconds into the motor burn time. The magnitudes of these perturbations are very small in comparison with the operating motor chamber pressure, which is over 600 psi during this time frame. These SRM pressure perturbations are believed to be caused primarily by the expulsion of slag (aluminum oxide). Two SRM static tests, TEM-11 and FSM-4, were instrumented extensive]y for the study of the phenomenon associated with pressure perturbations. The test instrumentation used included nonintrusive optical and infrared diagnostics of the plume, such as high-speed photography, radiometers, and thermal image cameras. Results from all these nonintrusive observations strongly support the scenario that the pressure perturbation event in the shuttle SRM is caused primarily by the expulsion of molten slag. The slag was also expelled preferentially near the bottom of the nozzle due to slag accumulation at the bottom of the aft end of the horizontally oriented motor.

Sambamurthi, J. K.; Alvarado, Alexis; Mathias, Edward C.

1995-01-01

15

New findings in static high-pressure science  

SciTech Connect

Recent static high P-T experiments using diamond anvil cell techniques reveal an array of phenomena and provide new links to dynamic compression experiments. Selected recent developments are reviewed, including new findings in hot dense hydrogen, the creation of new metals and superconductors, new transitions in molecular and other low-Z systems, the behavior of iron and transition metals, chemical changes of importance in geoscience and planetary science, and the creation of new classes of high-pressure devices based on CVD diamond. These advances have set the stage for the next set of developments in this rapidly growing area.

Hemley, R.J.; Mao, H.-k. (CIW)

2010-11-16

16

Radio jet refraction in galactic atmospheres with static pressure gradients  

NASA Technical Reports Server (NTRS)

A theory based on the refraction of radio jets in the extended atmosphere of an elliptical galaxy, is proposed for double radio sources with a Z or S morphology. The model describes a collimated jet of supersonic material that bends self-consistently under the influence of external static pressure gradients, and may alternatively be seen as a continuous-jet version of the buoyancy model proposed by Gull (1973). Emphasis is placed on (1) S-shaped radio sources identified with isolated galaxies, such as 3C 293, whose radio structures should be free of distortions resulting from motion relative to a cluster medium, and (2) small-scale, galaxy-dominated rather than environment-dominated S-shaped sources such as the inner jet structure of Fornax A.

Henriksen, R. N.; Vallee, J. P.; Bridle, A. H.

1981-01-01

17

Analysis of Fluctuating Static Pressure Measurements in a Large High Reynolds Number Transonic Cryogenic Wind Tunnel.  

National Technical Information Service (NTIS)

Dynamic measurements of fluctuating static pressure levels were made using flush mounted high frequency response pressure transducers at eleven locations in the circuit of the National Transonic Facility (NTF) over the complete operating range of this win...

W. B. Igoe

1991-01-01

18

Effects of static fingertip loading on carpal tunnel pressure  

NASA Technical Reports Server (NTRS)

The purpose of this study was to explore the relationship between carpal tunnel pressure and fingertip force during a simple pressing task. Carpal tunnel pressure was measured in 15 healthy volunteers by means of a saline-filled catheter inserted percutaneously into the carpal tunnel of the nondominant hand. The subjects pressed on a load cell with the tip of the index finger and with 0, 6, 9, and 12 N of force. The task was repeated in 10 wrist postures: neutral; 10 and 20 degrees of ulnar deviation; 10 degrees of radial deviation; and 15, 30, and 45 degrees of both flexion and extension. Fingertip loading significantly increased carpal tunnel pressure for all wrist angles (p = 0.0001). Post hoc analyses identified significant increase (p < 0.05) in carpal tunnel pressure between unloaded (0 N) and all loaded conditions, as well as between the 6 and 12 N load conditions. This study demonstrates that the process whereby fingertip loading elevates carpal tunnel pressure is independent of wrist posture and that relatively small fingertip loads have a large effect on carpal tunnel pressure. It also reveals the response characteristics of carpal tunnel pressure to fingertip loading, which is one step in understanding the relationship between sustained grip and pinch activities and the aggravation or development of median neuropathy at the wrist.

Rempel, D.; Keir, P. J.; Smutz, W. P.; Hargens, A.

1997-01-01

19

14 CFR 25.1325 - Static pressure systems.  

Code of Federal Regulations, 2010 CFR

...DEPARTMENT OF TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY AIRPLANES Equipment Instruments: Installation...system to a pressure differential of approximately 1 inch of mercury or to a reading on the altimeter, 1,000 feet above...

2010-01-01

20

14 CFR 25.1325 - Static pressure systems.  

Code of Federal Regulations, 2010 CFR

...DEPARTMENT OF TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY AIRPLANES Equipment Instruments: Installation...system to a pressure differential of approximately 1 inch of mercury or to a reading on the altimeter, 1,000 feet above...

2009-01-01

21

33 CFR 183.580 - Static pressure test for fuel tanks.  

Code of Federal Regulations, 2013 CFR

...Navigation and Navigable Waters 2 2013-07-01...2013-07-01 false Static pressure test for fuel tanks...Navigation and Navigable Waters COAST GUARD, DEPARTMENT... § 183.580 Static pressure test for fuel tanks...marked on the tank label under §...

2013-07-01

22

Hydrodynamics and mass transfer of a static mixer at high pressure conditions  

Microsoft Academic Search

The use of static mixers as alternative contacting devices for supercritical fluid separation processes has been proposed recently. Here, we present new data that addresses the hydrodynamic behavior and mass transfer kinetics of a Kenics-type static mixer under high pressure conditions. The gas pressure drop and the mass transfer coefficient for the fractionation of an oil mixture by supercritical carbon

Rui Ruivo; Alexandre Paiva; Pedro C. Simões

2006-01-01

23

ON RADIATION PRESSURE IN STATIC, DUSTY H II REGIONS  

SciTech Connect

Radiation pressure acting on gas and dust causes H II regions to have central densities that are lower than the density near the ionized boundary. H II regions in static equilibrium comprise a family of similarity solutions with three parameters: {beta}, {gamma}, and the product Q{sub 0} n{sub rms}; {beta} characterizes the stellar spectrum, {gamma} characterizes the dust/gas ratio, Q{sub 0} is the stellar ionizing output (photons/s), and n{sub rms} is the rms density within the ionized region. Adopting standard values for {beta} and {gamma}, varying Q{sub 0} n{sub rms} generates a one-parameter family of density profiles, ranging from nearly uniform density (small Q{sub 0} n{sub rms}) to shell-like (large Q{sub 0} n{sub rms}). When Q{sub 0} n{sub rms} {approx}> 10{sup 52} cm{sup -3} s{sup -1}, dusty H II regions have conspicuous central cavities, even if no stellar wind is present. For given {beta}, {gamma}, and Q{sub 0} n{sub rms}, a fourth quantity, which can be Q{sub 0}, determines the overall size and density of the H II region. Examples of density and emissivity profiles are given. We show how quantities of interest-such as the peak-to-central emission measure ratio, the rms-to-mean density ratio, the edge-to-rms density ratio, and the fraction of the ionizing photons absorbed by the gas-depend on {beta}, {gamma}, and Q{sub 0} n{sub rms}. For dusty H II regions, compression of the gas and dust into an ionized shell results in a substantial increase in the fraction of the stellar photons that actually ionize H (relative to a uniform-density H II region with the same dust/gas ratio and density n = n{sub rms}). We discuss the extent to which radial drift of dust grains in H II regions can alter the dust-to-gas ratio. The applicability of these solutions to real H II regions is discussed.

Draine, B. T., E-mail: draine@astro.princeton.edu [Princeton University Observatory, Peyton Hall, Princeton, NJ 08544 (United States)

2011-05-10

24

Sideslip-induced static pressure errors in flight-test measurements  

NASA Technical Reports Server (NTRS)

During lateral flight-test maneuvers of a V/STOL research aircraft, large errors in static pressure were observed. An investigation of the data showed a strong correlation of the pressure record with variations in sideslip angle. The sensors for both measurements were located on a standard air-data nose boom. An algorithm based on potential flow over a cylinder that was developed to correct the pressure record for sideslip-induced errors is described. In order to properly apply the correction algorithm, it was necessary to estimate and correct the lag error in the pressure system. The method developed for estimating pressure lag is based on the coupling of sideslip activity into the static ports and can be used as a standard flight-test procedure. The estimation procedure is discussed and the corrected static-pressure record for a typical lateral maneuver is presented. It is shown that application of the correction algorithm effectively attenuates sideslip-induced errors.

Parks, Edwin K.; Bach, Ralph E., Jr.; Tran, Duc

1990-01-01

25

Exact solutions: neutral and charged static perfect fluids with pressure  

NASA Astrophysics Data System (ADS)

We show in this article that charged fluid with pressure derived by Bijalwan (Astrophys. Space. Sci. doi:10.1007/s10509-011-0691-0, 011a) can be used to model classical electron, quark, neutron stars and pulsar with charge matter, quasi black hole, white dwarf, super-dense star etc. Recent analysis by Bijalwan (Astrophys. Space. Sci., 2011d) that all charged fluid solutions in terms of pressure mimic the classical electron model are partially correct because solutions by Bijalwan (Astrophys. Space. Sci. doi:10.1007/s10509-011-0691-0, 011a) may possess a neutral counterpart. In this paper we characterized solutions in terms of pressure for charged fluids that have and do not have a well behaved neutral counter part considering same spatial component of metric e ? for neutral and charged fluids. We discussed solution by Gupta and Maurya (Astrophys. Space Sci. 331(1):135-144, 2010a) and solutions by Bijalwan (Astrophys. Space Sci. doi:10.1007/s10509-011-0735-5, 2011b; Astrophys. Space Sci. doi:10.1007/s10509-011-0780-0, 2011c; Astrophys. Space Sci., 2011d) such that charged fluids possess and do not possess a neutral counterpart as special cases, respectively. For brevity, we only present some analytical results in this paper.

Bijalwan, Naveen

2012-01-01

26

Static pressure effects on calibration of velocity transducers at nozzle exits  

NASA Astrophysics Data System (ADS)

Calibrations of velocity transducers are generally performed at nozzle exits where the turbulence level is minimal. Such nozzles require a high contraction ratio and are usually short with a consequent effect on stream static pressure due to formation of a vena contracta. Calibrations performed with a Pitot tube and no static pressure correction can lead to a significant velocity error. Measurements of static pressure, mean velocity and turbulence intensity are presented for a typical high contraction ratio nozzle. These show two distinct flow regimes which can be described very simply by the Reynolds form of the Navier-Stokes equations.

Bremhorst, K.; Listijono, J.

1987-09-01

27

Rugged, no-moving-parts windspeed and static pressure probe designs for measurements in planetary atmospheres  

NASA Technical Reports Server (NTRS)

Instruments developed for making meteorological observations under adverse conditions on Earth can be applied to systems designed for other planetary atmospheres. Specifically, a wind sensor developed for making measurements within tornados is capable of detecting induced pressure differences proportional to wind speed. Adding strain gauges to the sensor would provide wind direction. The device can be constructed in a rugged form for measuring high wind speeds in the presence of blowing dust that would clog bearings and plug passages of conventional wind speed sensors. Sensing static pressure in the lower boundary layer required development of an omnidirectional, tilt-insensitive static pressure probe. The probe provides pressure inputs to a sensor with minimum error and is inherently weather-protected. The wind sensor and static pressure probes have been used in a variety of field programs and can be adapted for use in different planetary atmospheres.

Bedard, A. J., Jr.; Nishiyama, R. T.

1993-01-01

28

ROCKETS OR JATO JET ASSISTED TAKE OFF UNITS AT THE HIGH PRESSURE COMBUSTION FACILITY - STATIC FIRING  

NASA Technical Reports Server (NTRS)

ROCKETS OR JATO JET ASSISTED TAKE OFF UNITS AT THE HIGH PRESSURE COMBUSTION FACILITY - STATIC FIRING OF NITRIC ACID ANILINE ROCKET - PERMANGANATE PER OXIDE ROCKET SETUP INCLUDING TWO VIEWS THROUGH CONTROL ROOM SAFETY WINDOW

1946-01-01

29

Response of the Watts Bar, Maine Yankee and Bellefonte containments to static internal pressurization  

Microsoft Academic Search

As part of Sandia National Laboratories' Severe Accident Sequence Analysis (SASA) Program, structural analyses of the Watts Bar, Maine Yankee and Bellefonte containment structures were performed with the objective of obtaining realistic estimates of their ultimate static pressure capabilities. The Watts Bar investigation included analyses of the containment shell, equipment hatch, anchorage systems and personnel lock. The ultimate pressure capability

1983-01-01

30

Impact of static pressure on transmembrane fluid exchange in high molecular weight cut off microdialysis.  

PubMed

With the interest of studying larger biomolecules by microdialysis (MD), this sampling technique has reached into the ultrafiltration region of fluid exchange, where fluid recovery (FR) has a strong dependence on pressure. Hence in this study, we focus on the fluid exchange across the high molecular weight cut off MD membrane under the influence of the static pressure in the sampling environment. A theoretical model is presented for MD with such membranes, where FR has a linear dependence upon the static pressure of the sample. Transmembrane (TM) osmotic pressure difference and MD perfusion rate decide how fast FR increases with increased static pressure. A test chamber for in vitro MD under static pressure was constructed and validated. It can hold four MD probes under controlled pressurized conditions. Comparison showed good agreement between experiment and theory. Moreover, test results showed that the fluid recovery of the test chamber MD can be set accurately via the chamber pressure, which is controlled by sample injection into the chamber at precise rate. This in vitro system is designed for modelling in vivo MD in cerebrospinal fluid and studies with biological samples in this system may be good models for in vivo MD. PMID:24370572

Chu, Jiangtao; Hjort, Klas; Larsson, Anders; Dahlin, Andreas P

2014-04-01

31

Effect of empennage arrangement on single-engine nozzle/afterbody static pressures at transonic speeds  

NASA Technical Reports Server (NTRS)

An investigation has been conducted in the Langley 16-Foot Transonic Tunnel to determine the effects on empennage arrangement on single-engine nozzle/afterbody static pressures. Tests were done at Mach numbers from 0.60 to 1.20, nozzle pressure ratios from 1.0 (jet off) to 8.0. and angles of attack from -3 to 9 deg (at jet off conditions), depending on Mach number. Three empennage arrangements (aft, staggered, and forward) were investigated. Extensive measurements were made of static pressure on the nozzle/afterbody in the vicinity of the tail surfaces.

Henderson, William P.; Burley, James R., II

1987-01-01

32

Static pressure measurements in A 30 kWe class arcjet  

NASA Technical Reports Server (NTRS)

A series of cold and hot flow static pressure measurements have been made as a function of distance along the principal axis of a 30 kWe arcjet. During these experiments, the background pressure was varied from atmospheric pressure to less than 1 Torr. The experimental arcjet used in these tests had the same constrictor and conical nozzle dimensions as the baseline MOD-1 ammonia arcjet developed at NASA-JPL, but used nitrogen as the propellant gas. Comparison of the measured static pressure profiles with the arc erosion patterns on the anode surface showed that anode arc attachment points directly coincided with the minimum static pressure points. The dual voltage modes commonly observed in 30 kWe class arcjet thrusters are also believed to be caused by the presence of two pressure minima in the arcjet, one at the constrictor entrance and the other in the expansion nozzle. The static pressure profiles also suggest that the sonic flow transition occurs at the entrance to the nozzle, indicating the existence of very thick boundary layers in the arcjet constrictor.

Harris, William J.; O'Hair, Edgar A.; Hatfield, Lynn L.; Kristiansen, M.; Grimes, Montgomery D.

1991-01-01

33

Should care homes adopt a static-led approach to pressure ulcer prevention?  

PubMed

A static-led approach refers to the provision of high-specification foam mattresses for the whole of a population at risk of pressure damage. Such mattresses have been found to reduce the risk of pressure ulceration and cost less overall than standard mattresses, even in populations where only 1 in 100 patients develops a pressure ulcer. Reduced pressure ulcer prevalence and reduced costs resulting from decreased expenditure on dynamic mattresses following the implementation of a static-led approach have been reported. Pressure ulcers cause pain, a reduced quality of life, loss of independence, depression and social isolation for those in whom they develop. Organizations are increasingly having to pay out large sums of money following litigation surrounding pressure ulcers. This article explains why NHS healthcare providers and private care organizations need to work together to consider implementing a static-led approach to pressure ulcer prevention within care homes in order to reduce pressure ulcer incidence cost-effectively within their local populations. PMID:20081672

Keen, Delia Catherine

34

Static High Pressure X-Ray Diffraction of TI-6AL-4V  

SciTech Connect

Ti-6Al-4V was examined under static-high pressure conditions using a diamond anvil cell. The angle-dispersive x-ray diffraction experiments were performed at the Advanced Photon Source, Argonne National Laboratory. Radial and axial geometry were used to examine multiple samples. The purpose of the experiment was to generate pressure-volume data at room temperature (which is non-existent in literature) and to examine deviatoric stress effects on such a hard alloy.

Chesnut, Gary N.; Velisavljevic, Nenad; Sanchez, Lilliana (LANL)

2008-01-10

35

Ultrasonic characterization of plastic foams via measurements with static pressure variations  

NASA Astrophysics Data System (ADS)

A method for ultrasonic characterization of plastic foams by changing the static pressure of air that saturates the foam has been proposed. The method is based on high frequency asymptotic expressions of the standard Johnson-Allard equivalent fluid model. It is shown, both experimentally and theoretically, that the real part of squared acoustical refractive index and logarithm of the transmission coefficient depend linearly on the inverse of the square root of applied static pressure. These linear relations provide a simple and convenient way to determine experimentally the constitutive parameters. The method is illustrated with industrial open-cell foams. Advantages, limitations, and perspectives are discussed.

Ayrault, Christophe; Moussatov, Alexei; Castagnède, Bernard; Lafarge, Denis

1999-05-01

36

Pressure distribution and critical exponent in statically jammed and shear-driven frictionless disks  

NASA Astrophysics Data System (ADS)

We numerically study the distributions of global pressure that are found in ensembles of statically jammed and quasistatically sheared systems of bidisperse, frictionless disks at fixed packing fraction ? in two dimensions. We use these distributions to address the question of how pressure increases as ? increases above the jamming point ?J, p ˜|?-?J|y. For statically jammed ensembles, our results are consistent with the exponent y being simply related to the power law of the interparticle soft-core interaction. For sheared systems, however, the value of y is consistent with a nontrivial value, as found previously in rheological simulations.

Vâgberg, Daniel; Wu, Yegang; Olsson, Peter; Teitel, S.

2014-02-01

37

Sideslip-induced static pressure errors in flight-test measurements  

NASA Technical Reports Server (NTRS)

During lateral flight-test maneuvers of a V/STOL research aircraft, large errors in static pressure were observed. An investigation of the data showed a strong correlation of the pressure record with variations in sideslip angle. The sensors for both measurements were located on a standard air-data nose boom. This paper descries an algorithm based on potential flow over a cylinder that was developed to correct the pressure record for sideslip-induced errors. In order to properly apply the correction algorithm, it was necessary to estimate and correct the lag error in the pressure system. The method developed for estimating pressure lag is based on the coupling of sideslip activity into the static ports and can be used as a standard flight-test procedure. The paper discusses the estimation procedure and presents the corrected static-pressure record for a typical lateral maneuver. It is shown that application of the correction algorithm effectifvely attenuates sideslip-induced errors.

Parks, Edwin K.; Bach, Ralph E., Jr.; Tran, Duc

1990-01-01

38

Energy concentration and positional stability of sonoluminescent bubbles in sulfuric acid for different static pressures  

NASA Astrophysics Data System (ADS)

In this study we report several experimental and numerical results on the influence of static pressure (P0) over the main parameters in single bubble sonoluminescence (SBSL), using a sulfuric acid aqueous solution (SA) with low concentrations of argon gas dissolved. Bifrequency driving was used in the experiments to enhance spatial stability of the bubbles. The experimental results were compared with simulations provided by a numerical code that models the radial dynamics of the bubbles. The results showed that an increase on the static pressure of the system shifts the Bjerknes instability threshold, allowing the bubble to access higher acoustic pressures (PAc). Furthermore, a decrease in the measured ambient radius R0 and the calculated relative gas concentration c?/c0 were observed. A notorious increment in the bubble collapse violence and energy focusing for P0 above 1 bar was achieved. These were mainly indicated by the growth of the bubble expansion ratio (Rmax/R0), the bubble mechanical energy density, and the maximum bubble wall velocity dR/dt. In agreement with the previous statement, the maximum temperature during the bubble collapse predicted by the model is augmented as well. The use of different harmonics in the ultrasound pressure field regarding energy focusing is also discussed. Finally, we analyzed the stability regions of the R0-PAc parameter space via numerical predictions for P0 above the measured, identifying the shape instabilities as the main limiting agent to obtain further energy concentration in SA systems at high static pressures.

Rosselló, Juan Manuel; Dellavale, Damián; Bonetto, Fabián José

2013-09-01

39

The effect of static pressure on the strength of inertial cavitation events.  

PubMed

Recent investigations of cavitation in fluids pressurized up to 30 MPa found that the intensity of light emissions increased by 1000-fold over that measured for single bubble sonoluminescence. A series of measurements is reported here to extend this original work by resolving the static pressure dependence of the shock wave and light emissions from the first and the most energetic collapses, along with the total shock wave energy and light emissions for the event. Each of these parameters was found to increase with the static pressure of the fluid. Furthermore, the energy of these shock wave and light emissions was found to increase in proportion to the stored acoustic energy in the system. These findings were corroborated using the Gilmore equation to numerically compute the work done by the liquid during the bubble collapse. The overall findings suggest that the increased collapse strength at high static pressure is due to the increased tension required to generate inertial cavitation, and not an increased pressure gradient between the interior of the vaporous bubble and the surrounding liquid. PMID:23039425

Bader, Kenneth B; Mobley, Joel; Church, Charles C; Gaitan, D Felipe

2012-10-01

40

Investigation of Buried Domes. Phase II. Static Pressure Distribution on Small Rigid Domes.  

National Technical Information Service (NTIS)

Tests were conducted on a 9-inch-diameter solid hemispherical dome. The dome was buried in 20-30 Ottawa sand at various depths and was subjected to uniform static overpressures up to 300 psi. Pressures transmitted to the dome were measured by on-structure...

C. M. Reiff R. B. McPherson

1970-01-01

41

Device for Measuring Total and Static Pressures in Unsteady Gas-Dynamic Flows.  

National Technical Information Service (NTIS)

The object of the invention is a device for measuring the total and static pressures in unsteady gas-dynamic flows which contains pickups fastened to a forked holder in one of which at the end or face part and in the other in a lateral flow-through piezo ...

S. Y. Chernyavskii

1965-01-01

42

Triboelectric active sensor array for self-powered static and dynamic pressure detection and tactile imaging.  

PubMed

We report an innovative, large-area, and self-powered pressure mapping approach based on the triboelectric effect, which converts the mechanical stimuli into electrical output signals. The working mechanism of the triboelectric active sensor (TEAS) was theoretically studied by both analytical method and numerical calculation to gain an intuitive understanding of the relationship between the applied pressure and the responsive signals. Relying on the unique pressure response characteristics of the open-circuit voltage and short-circuit current, we realize both static and dynamic pressure sensing on a single device for the first time. A series of comprehensive investigations were carried out to characterize the performance of the TEAS, and high sensitivity (0.31 kPa(-1)), ultrafast response time (<5 ms), long-term stability (30,000 cycles), as well as low detection limit (2.1 Pa) were achieved. The pressure measurement range of the TEAS was adjustable, which means both gentle pressure detection and large-scale pressure sensing were enabled. Through integrating multiple TEAS units into a sensor array, the as-fabricated TEAS matrix was capable of monitoring and mapping the local pressure distribution applied on the device with distinguishable spatial profiles. This work presents a technique for tactile imaging and progress toward practical applications of nanogenerators, providing potential solutions for accomplishment of artificial skin, human-electronic interfacing, and self-powered systems. PMID:23957827

Lin, Long; Xie, Yannan; Wang, Sihong; Wu, Wenzhuo; Niu, Simiao; Wen, Xiaonan; Wang, Zhong Lin

2013-09-24

43

Non-linear optical properties of molecular systems under high static pressures  

NASA Astrophysics Data System (ADS)

Applied static pressure can largely modify the structure and dynamics of molecular systems, with consequences on their optical properties and chemical stability. When photochemical effects are exploited in conjunction with the structural and dynamical conditions attained at high density, chemical reactivity may become highly selective and efficient, yielding technologically attractive products. Non-linear optical spectroscopies are a powerful tool to investigate molecular energetics and dynamics, and thus unveil key aspects of the chemical reactivity at a molecular level. Their application to high-pressure samples is experimentally challenging, mainly because of the small sample dimensions and the non-linear effects generated in the anvil materials. In this paper we review the main results on the behavior of electronic states at high pressure, obtained by non-linear optical techniques, discussing the relationship between pressure-induced structural modifications and chemical reactivity, and the state of the art of ongoing research.

Citroni, M.; Fanetti, S.; Foggi, P.; Bini, R.

2014-05-01

44

Study of stator-vane fluctuating pressures in a turbofan engine for static and flight tests  

NASA Technical Reports Server (NTRS)

As part of a program to study the fan noise generated from turbofan engines, fluctuating surface pressures induced by fan-rotor wakes were measured on core- and bypass-stator outlet guide vanes of a modified JT15D-1 engine. Tests were conducted with the engine operating on an outdoor test stand and in flight. The amplitudes of pressures measured at fan-rotor blade-passage fundamental frequencies were generally higher and appeared less stable for the static tests than for the flight tests. Fluctuating pressures measured at the blade-passage frequency of the high-speed core compressor were interpreted to be acoustic; however, disturbance trace velocities for either the convected rotor wakes or acoustic pressures were difficult to interpret because of the complex environment.

Mueller, A. W.

1984-01-01

45

Quasi-static calibration of piezoelectric sensor using half-sine pressure pulse  

NASA Astrophysics Data System (ADS)

The quasi-static method with application of half-sine pressure pulse is presented to calibrate the piezoelectric sensor, which is used for the dynamic pressure measurement of weapons. A pressure generator based on the drop hammer hydraulic system is manufactured to get the half-sine pressure pulse. The oil cylinder of the generator is reconstructed to install four standard pressure sensors and two calibrated sensors simultaneously. With pressure taken from four standard sensors as calibrating excitation, and response data obtained from calibrated sensors, the working sensitivities of sensors are worked out through regression analysis. The experimental results obtained with sensor 6215 at the national shooting range shows that it is effective to calibrate piezoelectric sensors using half-sine pressure pulse. The residual standard deviation of the equation fitting is less than 0.7%; the linearity is less than 0.21%; and the relative uncertainty of the four standard sensors is less than 0.7%, under the precision target of the calibration system acceptance.

Zhang, Qicheng; Shang, Fei; Kong, Deren

2010-08-01

46

Plume Diagnostics of the RSRM Static Firings for the Pressure Perturbation Studies  

NASA Technical Reports Server (NTRS)

During the STS-54 launch (RSRM-29), the right hand solid rocket motor experienced a 13.9 psi chamber pressure perturbation at 67 seconds into the motor operation. This pressure augmentation equated to a thrust change of 51 klb. Concerns were raised regarding the adverse effects of this thrust imbalance on the shuttle system and the overall thrust into the external tank structural elements. Pressure perturbations have been observed in solid rocket motors due to expulsion of igniter or insulation materials; the motor thrust during such events drop abruptly before rising. However, the RSRM motors do not exhibit such behavior during the large chamber pressure perturbation events. Several scenarios were investigated to explain these pressure perturbations in the RSRM motors based on a fault tree developed after STS-54. Of these, the expulsion of the slag accumulated in the submerged nozzle region appeared to be the most plausible scenario to explain the observations. Slag is a natural combustion product of aluminized solid rocket motors. The RSRM propellant contains 16% by weight of aluminum. Any ejection of this slag mass during nozzle vectoring or other side loads on the motor will result in the chamber pressure perturbation. Two RSRM static firings were instrumented extensively to further understand the slag expulsion phenomenon in the RSRM and the associated pressure perturbations.

Mathias, Edward C.; Sambamurthi, Jay K.; Alvarado, Alexis

1995-01-01

47

Static pressure correction in high Reynolds number fully developed turbulent pipe flow  

NASA Astrophysics Data System (ADS)

Measurements are reported of the error in wall static pressure reading due to the finite size of the pressure tapping. The experiments were performed in incompressible turbulent pipe flow over a wide range of Reynolds numbers, and the results indicate that the correction term (as a fraction of the wall stress) continues to increase as the hole Reynolds number d^+=u_? d/? increases, contrary to previous studies. For small holes relative to the pipe diameter the results follow a single curve, but for larger holes the data diverge from this universal behaviour at a point that depends on the ratio of the hole diameter to the pipe diameter.

McKeon, B. J.; Smits, A. J.

2002-10-01

48

Heart Rate Variability and Blood Pressure during Dynamic and Static Exercise at Similar Heart Rate Levels  

PubMed Central

Aim was to elucidate autonomic responses to dynamic and static (isometric) exercise of the lower limbs eliciting the same moderate heart rate (HR) response. Method: 23 males performed two kinds of voluntary exercise in a supine position at similar heart rates: static exercise (SE) of the lower limbs (static leg press) and dynamic exercise (DE) of the lower limbs (cycling). Subjective effort, systolic (SBP) and diastolic blood pressure (DBP), mean arterial pressure (MAP), rate pressure product (RPP) and the time between consecutive heart beats (RR-intervals) were measured. Time-domain (SDNN, RMSSD), frequency-domain (power in the low and high frequency band (LFP, HFP)) and geometric measures (SD1, SD2) as well as non-linear measures of regularity (approximate entropy (ApEn), sample entropy (SampEn) and correlation dimension D2) were calculated. Results: Although HR was similar during both exercise conditions (88±10 bpm), subjective effort, SBP, DBP, MAP and RPP were significantly enhanced during SE. HRV indicators representing overall variability (SDNN, SD 2) and vagal modulated variability (RMSSD, HFP, SD 1) were increased. LFP, thought to be modulated by both autonomic branches, tended to be higher during SE. ApEn and SampEn were decreased whereas D2 was enhanced during SE. It can be concluded that autonomic control processes during SE and DE were qualitatively different despite similar heart rate levels. The differences were reflected by blood pressure and HRV indices. HRV-measures indicated a stronger vagal cardiac activity during SE, while blood pressure response indicated a stronger sympathetic efferent activity to the vessels. The elevated vagal cardiac activity during SE might be a response mechanism, compensating a possible co-activation of sympathetic cardiac efferents, as HR and LF/HF was similar and LFP tended to be higher. However, this conclusion must be drawn cautiously as there is no HRV-marker reflecting “pure” sympathetic cardiac activity.

Weippert, Matthias; Behrens, Kristin; Rieger, Annika; Stoll, Regina; Kreuzfeld, Steffi

2013-01-01

49

Energy concentration and positional stability of sonoluminescent bubbles in sulfuric acid for different static pressures.  

PubMed

In this study we report several experimental and numerical results on the influence of static pressure (P_{0}) over the main parameters in single bubble sonoluminescence (SBSL), using a sulfuric acid aqueous solution (SA) with low concentrations of argon gas dissolved. Bifrequency driving was used in the experiments to enhance spatial stability of the bubbles. The experimental results were compared with simulations provided by a numerical code that models the radial dynamics of the bubbles. The results showed that an increase on the static pressure of the system shifts the Bjerknes instability threshold, allowing the bubble to access higher acoustic pressures (P_{Ac}^{}). Furthermore, a decrease in the measured ambient radius R_{0} and the calculated relative gas concentration c_{?}/c_{0} were observed. A notorious increment in the bubble collapse violence and energy focusing for P_{0} above 1 bar was achieved. These were mainly indicated by the growth of the bubble expansion ratio (R_{max}/R_{0}), the bubble mechanical energy density, and the maximum bubble wall velocity dR/dt. In agreement with the previous statement, the maximum temperature during the bubble collapse predicted by the model is augmented as well. The use of different harmonics in the ultrasound pressure field regarding energy focusing is also discussed. Finally, we analyzed the stability regions of the R_{0}-P_{Ac}^{} parameter space via numerical predictions for P_{0} above the measured, identifying the shape instabilities as the main limiting agent to obtain further energy concentration in SA systems at high static pressures. PMID:24125363

Rosselló, Juan Manuel; Dellavale, Damián; Bonetto, Fabián José

2013-09-01

50

Probe systems for measuring static pressure and turbulence intensity in fluid streams  

NASA Technical Reports Server (NTRS)

A method and an apparatus for measuring time-averaged static or ambient pressure and turbulence intensity in a turbulent stream are discussed. The procedure involves placing a plurality of probes in the stream. Each probe responds in a different manner to characteristics of the fluid stream, preferably as a result of having varying cross sections. The responses from the probes are used to eliminate unwanted components in the measured quantities for accurate determination of selected characteristics.

Rossow, Vernon J. (inventor)

1993-01-01

51

Analysis of Fluctuating Static Pressure Measurements in the National Transonic Facility  

NASA Technical Reports Server (NTRS)

Dynamic measurements of fluctuating static pressure levels were taken with flush-mounted, high-frequency response pressure transducers at 11 locations in the circuit of the National Transonic Facility (NTF) across the complete operating range of this wind tunnel. Measurements were taken at test-section Mach numbers from 0.1 to 1.2, at pressures from 1 to 8.6 atm, and at temperatures from ambient to -250 F, which resulted in dynamic flow disturbance measurements at the highest Reynolds numbers available in a transonic ground test facility. Tests were also made by independent variation of the Mach number, the Reynolds number, or the fan drive power while the other two parameters were held constant, which for the first time resulted in a distinct separation of the effects of these three important parameters.

Igoe, William B.

1996-01-01

52

Transient cavitation in high-quality-factor resonators at high static pressures.  

PubMed

It is well known that cavitation collapse can generate intense concentrations of mechanical energy, sufficient to erode even the hardest metals and to generate light emissions visible to the naked eye [sonoluminescence (SL)]. Considerable attention has been devoted to the phenomenon of "single bubble sonoluminescence" (SBSL) in which a single stable cavitation bubble radiates light flashes each and every acoustic cycle. Most of these studies involve acoustic resonators in which the ambient pressure is near 0.1 MPa (1 bar), and with acoustic driving pressures on the order of 0.1 MPa. This study describes a high-quality factor, spherical resonator capable of achieving acoustic cavitation at ambient pressures in excess of 30 MPa (300 bars). This system generates bursts of violent inertial cavitation events lasting only a few milliseconds (hundreds of acoustic cycles), in contrast with the repetitive cavitation events (lasting several minutes) observed in SBSL; accordingly, these events are described as "inertial transient cavitation." Cavitation observed in this high pressure resonator is characterized by flashes of light with intensities up to 1000 times brighter than SBSL flashes, as well as spherical shock waves with amplitudes exceeding 30 MPa at the resonator wall. Both SL and shock amplitudes increase with static pressure. PMID:20550245

Gaitan, D Felipe; Tessien, Ross A; Hiller, Robert A; Gutierrez, Joel; Scott, Corey; Tardif, Henry; Callahan, Brant; Matula, Thomas J; Crum, Lawrence A; Holt, R Glynn; Church, Charles C; Raymond, Jason L

2010-06-01

53

Static pressure drives proliferation of vascular smooth muscle cells via caveolin-1/ERK1/2 pathway  

SciTech Connect

Intimal hyperplasia plays an important role in various types of vascular remodeling. Mechanical forces derived from blood flow are associated with the proliferation of vascular smooth muscle cells (VSMC). This contributes to many vascular disorders such as hypertension, atherosclerosis and restenosis after percutaneous transluminal angioplasty (PTA). In this study, we show that static pressure induces the proliferation of VSMC and activates its related signal pathway. VSMC from a rat aorta were treated with different pressures (0, 60, 90, 120, 150 and 180 mm Hg) in a custom-made pressure incubator for 24 h. The most active proliferation of VSMC was detected at a pressure of 120 mm Hg. VSMC was also incubated under a static pressure of 120 mm Hg for different time intervals (0, 2, 4, 8, 12 and 24 h). We found that static pressure significantly stimulates VSMC proliferation. Extracellular signal-regulated kinases 1/2 (ERK1/2) activation showed a peak at the pressure of 120 mm Hg at 4-h time point. Moreover, caveolin-1 expression was significantly inhibited by rising static pressure. Downregulation of VSMC proliferation could be found after PD98059 (ERK1/2 phosphorylation inhibitor) treatment. Our data also showed that a siRNA-mediated caveolin-1 knock down increased ERK1/2 phosphorylation and VSMC proliferation. These results demonstrate that static pressure promotes VSMC proliferation via the Caveolin-1/ERK1/2 pathway.

Luo, Di-xian, E-mail: luodixian_2@163.com [Division of Pharmacoproteomics, Institute of Pharmacy and Pharmacology, Research Center of Life Science, University of South China, Hengyang, Hunan 421001 (China) [Division of Pharmacoproteomics, Institute of Pharmacy and Pharmacology, Research Center of Life Science, University of South China, Hengyang, Hunan 421001 (China); Department of Pharmacology, School of Pharmaceutics, Central South University, Changsha, Hunan 410083 (China); The First People's Hospital of Chenzhou City, Chenzhou, Hunan 421001 (China); Cheng, Jiming [Internal Medicine and SimmonsCooper Cancer Institute, Southern Illinois University School of Medicine, 911 N. Rutledge Street, Springfield, IL 62794-9626 (United States) [Internal Medicine and SimmonsCooper Cancer Institute, Southern Illinois University School of Medicine, 911 N. Rutledge Street, Springfield, IL 62794-9626 (United States); Suzhou Health College of Technology, 20 Shuyuanxiang, Suzhou, Jiangsu 215002 (China); Xiong, Yan [Department of Pharmacology, School of Pharmaceutics, Central South University, Changsha, Hunan 410083 (China)] [Department of Pharmacology, School of Pharmaceutics, Central South University, Changsha, Hunan 410083 (China); Li, Junmo [Division of Pharmacoproteomics, Institute of Pharmacy and Pharmacology, Research Center of Life Science, University of South China, Hengyang, Hunan 421001 (China)] [Division of Pharmacoproteomics, Institute of Pharmacy and Pharmacology, Research Center of Life Science, University of South China, Hengyang, Hunan 421001 (China); Xia, Chenglai [Division of Pharmacoproteomics, Institute of Pharmacy and Pharmacology, Research Center of Life Science, University of South China, Hengyang, Hunan 421001 (China) [Division of Pharmacoproteomics, Institute of Pharmacy and Pharmacology, Research Center of Life Science, University of South China, Hengyang, Hunan 421001 (China); School of Pharmaceutics, Southern Medical University, Guangzhou, Guangdong 510515 (China); Xu, Canxin; Wang, Chun; Zhu, Bingyang [Division of Pharmacoproteomics, Institute of Pharmacy and Pharmacology, Research Center of Life Science, University of South China, Hengyang, Hunan 421001 (China)] [Division of Pharmacoproteomics, Institute of Pharmacy and Pharmacology, Research Center of Life Science, University of South China, Hengyang, Hunan 421001 (China); Hu, Zhuowei [Institute of Materia Medical, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100730 (China)] [Institute of Materia Medical, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100730 (China); Liao, Duan-fang, E-mail: dfliao66@yahoo.com.cn [Division of Pharmacoproteomics, Institute of Pharmacy and Pharmacology, Research Center of Life Science, University of South China, Hengyang, Hunan 421001 (China)] [Division of Pharmacoproteomics, Institute of Pharmacy and Pharmacology, Research Center of Life Science, University of South China, Hengyang, Hunan 421001 (China)

2010-01-22

54

Au-Ag Alloy Static High Pressure EOS measurements: FY09 summary of results  

SciTech Connect

Static high-pressure measurements of the equation of state of a Gold-Silver alloy (23.5 wt-% Ag) at room temperature were performed up to a pressure of approximately 100 GPA (1 megabar). Measurements were made using an energy-dispersive x-ray diffraction method. The data was analyzed, yielding crystal structure lattice constants and volume/density as a function of pressure. The results are extremely precise yielding accuracy of better than 1%. The experiments were carried out at the HPCAT 16BM-D beamline at the Advanced Photon Source. Two experiments on separate samples were carried out using conventional membrane diamond anvil cells. To achieve hydrostatic conditions, we loaded a 50-100 micron piece of the Au-Ag alloy into the cell and surrounded it with neon and mineral oil pressure media in the respective experiments. The differing pressure media demonstrated no measurable difference on the resultant crystal structures, lattice constants or pressure-volume curves. Results of our work are shown in the figures below. Up to the maximum pressure of 100 GPa the sample remained in the face-centered cubic structure, e.g., we observed no change in crystal structure. EOS curves of silver and gold, taken from the literature, are shown for comparison. We fit our data to a Vinet EOS functional form, and the parameters for this EOS were found to be, Reference (ambient pressure) volume, V{sub 0} = 16.965435 {angstrom}{sup 3}; Reference (ambient pressure) density, {rho}{sub 0} = 16.14584 g/cm{sup 3}; Bulk Modulus, K{sub 0} = 144 GPa; and Bulk Mod Derivative, K{prime}{sub 0} = 5.66. As one might expect the Au-Ag alloy lies between the gold and silver EOS curves, and tracks more closely to the gold EOS. These data are useful in validating and developing predictive EOS models of the pressure-dependent behavior of Au-Ag alloys.

Evans, W J; Jenei, Z

2009-09-17

55

Vibration of pseudo-shock in straight duct. I - Fluctuation of static pressure  

NASA Astrophysics Data System (ADS)

Vibration of a pseudoshock in a duct often causes noise, vibration and breakdown of the duct. In the present study, the wall static-pressure fluctuation was measured along the duct and statistically analyzed to make clear the mechanism of the pseudoshock vibration. The result showed that the vibration had two main frequencies. The higher frequency was the natural frequency of the air column in the divergent passage attached downstream of the duct, and the pressure fluctuation propagated in the upstream direction. The lower frequency was the natural frequency of the air column in the duct downstream of the pseudoshock, and this disturbance propagated in the downstream direction. Both vibrations were maintained by their interaction.

Yamane, R.; Kondo, E.; Tomita, Y.; Sakae, N.

1984-07-01

56

Ultrafast high strain rate acoustic wave measurements at high static pressure in a diamond anvil cell  

SciTech Connect

We have used sub-picosecond laser pulses to launch ultra-high strain rate ({approx} 10{sup 9} s{sup -1}) nonlinear acoustic waves into a 4:1 methanol-ethanol pressure medium which has been precompressed in a standard diamond anvil cell. Using ultrafast interferometry, we have characterized acoustic wave propagation into the pressure medium at static compression up to 24 GPa. We find that the velocity is dependent on the incident laser fluence, demonstrating a nonlinear acoustic response which may result in shock wave behavior. We compare our results with low strain, low strain-rate acoustic data. This technique provides controlled access to regions of thermodynamic phase space that are otherwise difficult to obtain.

Armstrong, M; Crowhurst, J; Reed, E; Zaug, J

2008-02-04

57

The effects of confining pressure and stress difference on static fatigue of granite  

NASA Technical Reports Server (NTRS)

Samples of Barre granite were creep tested at room temperature at confining pressures up to 2 kilobars. The time to fracture increased with decreasing stress difference at every pressure, but the rate of change of fracture time with respect to the stress difference increased with pressure. At 87% of the short-term fracture strength, the time to fracture increased from about 4 minutes at atmospheric pressure to longer than one day at 2 Kb of pressure. The inelastic volumetric strain at the onset of tertiary creep, delta, was constant within 25% at any particular pressure but increased with pressure in a manner analogous to the increase of strength with pressure. At the onset of tertiary creep, the number of cracks and their average length increased with pressure. The crack angle and crack length spectra were quite similar, however, at each pressure at the onset of tertiary creep.

Kranz, R. L.

1979-01-01

58

Vibration of pseudo-shock in straight duct. II - Correlation of static pressure fluctuation  

Microsoft Academic Search

Pressure fluctuations at two points along a straight duct were simultaneously measured and correlated statistically in the forms of correlation factors and coherences to investigate the propagation of the pressure fluctuation. The variation of a pseudoshock had two main frequencies: the higher, the vibration of the air column in the divergent passage, propagated upstream as a pressure wave; the lower

R. Yamane; M. Takahashi; H. Saito

1984-01-01

59

Heart rate and arterial blood pressure at the onset of static exercise in man with complete neural blockade.  

PubMed Central

1. We tested the 'muscle-heart reflex' hypothesis for the immediate increases in heart rate and blood pressure at the onset of static exercise in man by performing complete blockade of afferent nerves from the working muscles. Brief (5 s) maximal static hand-grip contractions were performed without performing a Valsalva-like manoeuvre and with no increase in central venous pressure both before and after combined axillary and radial blockade with lidocaine. Muscle strength was reduced to near zero. The effectiveness of the afferent neural blockade was evaluated by recording the heart rate and blood pressure responses and rating the perceived pain during a cold pressor test of the blocked and contralateral unblocked hand. 2. The cold pressor test increased blood pressure but had no effect on heart rate. Afferent neural blockade eliminated the increase in blood pressure and the perceived pain associated with the cold pressor test. Maximal hand-grip contractions resulted in immediate and similar increases in heart rate and blood pressure before and after afferent neural blockade of the arm. 3. The results of this study suggest that the immediate increases in heart rate and blood pressure at the onset of static exercise in man occur when the 'muscle-heart reflex' is inoperable. Images Fig. 1

Friedman, D B; Jensen, F B; Mitchell, J H; Secher, N H

1990-01-01

60

Vibration of pseudo-shock in straight duct. II - Correlation of static pressure fluctuation  

NASA Astrophysics Data System (ADS)

Pressure fluctuations at two points along a straight duct were simultaneously measured and correlated statistically in the forms of correlation factors and coherences to investigate the propagation of the pressure fluctuation. The variation of a pseudoshock had two main frequencies: the higher, the vibration of the air column in the divergent passage, propagated upstream as a pressure wave; the lower propagated convectionally with the main flow.

Yamane, R.; Takahashi, M.; Saito, H.

1984-07-01

61

On the growth of steam droplets formed in a Laval nozzle using both static pressure and light scattering measurements  

Microsoft Academic Search

A series of experiments on steam condensation have been made in a Laval nozzle over a variety of starting conditions such that the onset of condensation occurs in the range -40 to 40 C. The homogeneous nucleation and growth of the new phase is documented with both static pressure and laser light scattering. Since even at onset the majority of

C. A. Moses; G. D. Stein

1977-01-01

62

Curvature pressure: Sufficient fo a static and stable cosmology; important for solar neutrino production and black hole formation  

Microsoft Academic Search

A hypothesis is presented that electromagnetic forces that prevent ions from following geodesics results in a curvature pressure that is very important in astrophysics. It may partly explain the solar neutrino deficiency and it may be the engine that drives astrophysical jets. However its most important consequence is that it leads to a static and stable cosmology using general relativity

David F. Crawford

1998-01-01

63

Stimulation of the Vestibular Apparatus in the Guinea Pig by Static Pressure Changes: Head and Eye Movements.  

National Technical Information Service (NTIS)

Head and eye movements elicited by static pressure increases of up to 1-min duration in the external auditory meatus were recorded using guinea pigs as subjects. The minimum stimulus intensity required to produce a response was 1.5-2.0 cm Hg. Observations...

D. E. Parker H. E. von Gierke M. F. Reschke

1970-01-01

64

Structural Phase Stability in Group IV Metals Under Static High Pressure  

Microsoft Academic Search

In group IV metals (Ti, Zr, and Hf) room temperature compression leads to a martensitic transformation from a ductile alpha to a brittle omega phase. The alpha-->omega phase boundary decreases to lower pressure at high temperature and can limit the use of group IV metals in industrial applications. There is a large discrepancy in the transition pressure reported in literature,

N. Velisavljevic; G. N. Chesnut; D. M. Dattelbaum; Y. K. Vohra; A. Stemshorn

2009-01-01

65

STRUCTURAL PHASE STABILITY IN GROUP IV METALS UNDER STATIC HIGH PRESSURE  

Microsoft Academic Search

In group IV metals (Ti, Zr, and Hf) room temperature compression leads to a martensitic transformation from a ductile ? to a brittle ? phase. The ??? phase boundary decreases to lower pressure at high temperature and can limit the use of group IV metals in industrial applications. There is a large discrepancy in the transition pressure reported in literature,

N. Velisavljevic; G. N. Chesnut; D. M. Dattelbaum; Y. K. Vohra; A. Stemshorn

2009-01-01

66

Structural Phase Stability in Group IV Metals Under Static High Pressure  

Microsoft Academic Search

In group IV metals (Ti, Zr, and Hf) room temperature compression leads to a martensitic transformation from a ductile alpha to a brittle phi phase. alpha-phi phase boundary decreases to lower pressure at high temperature and can limit the use of group IV metals in industrial applications. There is a large discrepancy in the transition pressure reported in literature, with

Nenad Velisavljevic; Garry N Chesnut; Dana M Dattelbaum; Yogesh K Vohra; Andrew Stemshorn

2009-01-01

67

Modeling subharmonic response from contrast microbubbles as a function of ambient static pressure  

PubMed Central

Variation of subharmonic response from contrast microbubbles with ambient pressure is numerically investigated for non-invasive monitoring of organ-level blood pressure. Previously, several contrast microbubbles both in vitro and in vivo registered approximately linear (5–15 dB) subharmonic response reduction with 188 mm Hg change in ambient pressure. In contrast, simulated subharmonic response from a single microbubble is seen here to either increase or decrease with ambient pressure. This is shown using the code BUBBLESIM for encapsulated microbubbles, and then the underlying dynamics is investigated using a free bubble model. The ratio of the excitation frequency to the natural frequency of the bubble is the determining parameter—increasing ambient pressure increases natural frequency thereby changing this ratio. For frequency ratio below a lower critical value, increasing ambient pressure monotonically decreases subharmonic response. Above an upper critical value of the same ratio, increasing ambient pressure increases subharmonic response; in between, the subharmonic variation is non-monotonic. The precise values of frequency ratio for these three different trends depend on bubble radius and excitation amplitude. The modeled increase or decrease of subharmonic with ambient pressure, when one happens, is approximately linear only for certain range of excitation levels. Possible reasons for discrepancies between model and previous experiments are discussed.

Katiyar, Amit; Sarkar, Kausik; Forsberg, Flemming

2011-01-01

68

A Lagrange-multiplier-based XFEM to solve pressure Poisson equations in problems with quasi-static interfaces  

NASA Astrophysics Data System (ADS)

The XFEM (extended finite element method) has a lot of advantages over other numerical methods to resolve discontinuities across quasi-static interfaces due to the jump in fluidic parameters or surface tension. However, singularities corresponding to enriched degrees of freedom (DOFs) embedded in XFEM arise in the discrete pressure Poisson equations. In this paper, constraints on these DOFs are derived from the interfacial equilibrium condition and introduced in terms of stabilized Lagrange multipliers designed for non-boundary-fitted meshes to address this issue. Numerical results show that the weak and strong discontinuities in pressure with straight and circular interfaces are accurately reproduced by the constraints. Comparisons with the SUPG/PSPG (streamline upwind/pressure stabilizing Petrov-Galerkin) method without Lagrange multipliers validate the applicability and flexibility of the proposed constrained algorithm to model problems with quasi-static interfaces.

Liao, JianHui; Zhuang, Zhuo

2012-04-01

69

Influence of surface static-pressure orifices on boundary-layer transition. [tests conducted in the Langley Low-Turbulence Pressure Tunnel  

NASA Technical Reports Server (NTRS)

An investigation of the interaction of a laminar boundary layer and surface static-pressure orifices was conducted on a natural laminar flow airfoil. The effects of both favorable and adverse pressure gradients were studied at Reynolds numbers based on airfoil chord from approximately 500,000 to 6,000,000 with Mach number varying accordingly from about 0.03 to 0.42. The smaller the diameter of the orifice, the less likely it will cause premature transition. Locating the orifices in a chord-wise row aligned with the flow appears to have an additive, adverse effect on transition. Tube length-to-orifice diameter ration does not seem to have a consistent influence on transition.

Somers, D. M.; Stack, J. P.; Harvey, W. D.

1982-01-01

70

Significant static pressure increase in a precompression cell target for laser-driven advanced dynamic compression experiments  

SciTech Connect

Laser shock compression experiments on precompressed samples offer the possibility to explore extreme material states unreachable by static or single-shock compression techniques alone. We have found significant increases in static compression pressure in a wide-opening and thin diamond precompression cell. This suggests that the precompression target is adaptable to advanced coupling techniques with laser-driven dynamic compression methods. The novel coupling techniques proposed give the potential to access outstanding material states required in planetary and condensed-matter physics.

Kimura, T.; Ozaki, N.; Terai, T.; Sano, T.; Hirose, A.; Kakeshita, T.; Kodama, R. [Graduate School of Engineering, Osaka University, Suita, Osaka 565-0871 (Japan); Okuchi, T. [Institute for Study of the Earth's Interior, Okayama University, Misasa, Tottori 682-0193 (Japan); Shimizu, K. [KYOKUGEN, Center for Quantum Science and Technology Under Extreme Conditions, Osaka University, Toyonaka, Osaka 560-8531 (Japan); Sano, T.; Sakawa, Y. [Institute of Laser Engineering, Osaka University, Suita, Osaka 565-0871 (Japan); Koenig, M. [Laboratoire pour l'Utilisation des Lasers Intenses, UMR7605, CNRS-CEA-Universite Paris VI-Ecole Polytechnique, 91128 Palaiseau Cedex (France)

2010-05-15

71

Structural phase stability in group IV metals under static high pressure  

SciTech Connect

In group IV metals (Ti, Zr, and Hf) room temperature compression leads to a martensitic transformation from a ductile {alpha} to a brittle {omega} phase. {alpha} {yields} {omega} phase boundary decreases to lower pressure at high temperature and can limit the use of group IV metals in industrial applications. There is a large discrepancy in the transition pressure reported in literature, with some of the variation attributed to experimental conditions (i.e. hydrostatic vs. non-hydrostatic). Shear deformation in non-hydrostatic experiments drives {alpha} {yields} {omega} transition and decreases transition pressure. Impurities can also aid or suppress {alpha} {yields} {omega} transition. By performing x-ray diffraction experiments on samples in a diamond anvil cell we show that interstitial impurities, such as C, N, and O can obstruct {alpha} {yields} {omega} transition and stabilize {alpha} phase to higher pressure. We also show that reduction in grain size can also influence {alpha} {yields} {omega} phase boundary and help stabilize {alpha} phase to higher pressure under non-hydrostatic conditions.

Velisavljevic, Nenad [Los Alamos National Laboratory; Chesnut, Garry N [Los Alamos National Laboratory; Dattelbaum, Dana M [Los Alamos National Laboratory; Vohra, Yogesh K [U OF ALABAMA AT BIRMINGHAM; Stemshorn, Andrew [U OF ALABAMA AT BIRMINGHAM

2009-01-01

72

Brine flow up a borehole caused by pressure perturbation from CO2 storage: Static and dynamic evaluations  

SciTech Connect

Industrial-scale storage of CO{sub 2} in saline sedimentary basins will cause zones of elevated pressure, larger than the CO{sub 2} plume itself. If permeable conduits (e.g., leaking wells) exist between the injection reservoir and overlying shallow aquifers, brine could be pushed upwards along these conduits and mix with groundwater resources. This paper discusses the potential for such brine leakage to occur in temperature- and salinity-stratified systems. Using static mass-balance calculations as well as dynamic well flow simulations, we evaluate the minimum reservoir pressure that would generate continuous migration of brine up a leaking wellbore into a freshwater aquifer. Since the brine invading the well is denser than the initial fluid in the wellbore, continuous flow only occurs if the pressure perturbation in the reservoir is large enough to overcome the increased fluid column weight after full invasion of brine into the well. If the threshold pressure is exceeded, brine flow rates are dependent on various hydraulic (and other) properties, in particular the effective permeability of the wellbore and the magnitude of pressure increase. If brine flow occurs outside of the well casing, e.g., in a permeable fracture zone between the well cement and the formation, the fluid/solute transfer between the migrating fluid and the surrounding rock units can strongly retard brine flow. At the same time, the threshold pressure for continuous flow to occur decreases compared to a case with no fluid/solute transfer.

Birkholzer, J.T.; Nicot, J.-P.; Oldenburg, C.M.; Zhou, Q.; Kraemer, S.; Bandilla, K.W.

2011-05-01

73

Curvature pressure: Sufficient fo a static and stable cosmology; important for solar neutrino production and black hole formation  

Microsoft Academic Search

A hypothesis is presented that electromagnetic forces that prevent ions from\\u000afollowing geodesics results in a curvature pressure that is very important in\\u000aastrophysics. It may partly explain the solar neutrino deficiency and it may be\\u000athe engine that drives astrophysical jets. However its most important\\u000aconsequence is that it leads to a static and stable cosmology using general\\u000arelativity

David F. Crawford

1998-01-01

74

Static internal pressure capacity of Hanford Single-Shell Waste Tanks  

SciTech Connect

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

Julyk, L.J.

1994-07-19

75

Contrast sensitivity versus static visual field testing during experimental elevation of intraocular pressure  

Microsoft Academic Search

Contrast sensitivity testing has been recommended as a more sensitive indicator of early visual loss than visual field testing. Using gravity inversion to induce an intraocular pressure rise, we performed contrast sensitivity testing on each eye of 10 normal subjects in the upright and inverted positions. Contrast sensitivity results were not altered in the head-down position, even though in 5

Thomas R. Friberg; George E. Sanborn; Robert Budd

1989-01-01

76

Selection and static calibration of the Marsh J1678 pressure gauge  

NASA Astrophysics Data System (ADS)

During the experimental testing of the ultralight, it was determined that a pressure gauge would be required to monitor the simulated flight loads. After analyzing several factors, which are indicated in the discussion section of this report, the Marsh J1678 pressure gauge appeared to be the prominent candidate for the task. However, prior to the final selection, the Marsh pressure gauge was calibrated twice by two different techniques. As a result of the calibration, the Marsh gauge was selected as the appropriate measuring device during the structural testing of the ultralight. Although, there are commerical pressure gauges available on the market that would have proven to be more efficient and accurate. However, in order to obtain these characteristics in a gauge, one has to pay the price on the price tag, and this value is an exponential function of the degree of accuracy efficiency, precision, and many other features that may be designed into the gauge. After analyzing the extent of precision and accuracy that would be required, a more expensive gauge wouldn't have proven to be a financial benefit towards the outcome of the experiment.

Oxendine, Charles R.; Smith, Howard W.

77

Dynamic and static shell properties of white and brown shell eggs exposed to modified pressure microcrack detection technology.  

PubMed

Dynamic and static shell properties of eggs provide important insight to egg quality. Understanding how processing and handling procedures affect both dynamic and static shell properties can enhance the safety and quality of eggs reaching the consumer. A study was conducted to determine if dynamic shell properties were altered due to modified pressure microcrack detection technology exposure in brown and white shell eggs. Three replicates of 100 eggs each of brown and white retail shell eggs were conducted. Dynamic stiffness (K(dyn)) and egg weight were monitored immediately before and after microcrack detection. No changes in K(dyn) or egg weight were detected for either shell color. Static compression shell strength and deformation were subsequently monitored and a correlation analysis conducted. A strong correlation (R(2) = 0.53; P < 0.0001) between K(dyn) and static compression shell strength was seen for extra large white shell eggs. A smaller (R(2) = 0.31; P < 0.0001) correlation was found for large brown eggs. The use of modified pressure microcrack detection technology did not affect shell dynamic properties. PMID:22991554

Jones, D R; Broussard, V; Lawrence, K C; Yoon, S C; Heitschmidt, G W

2012-10-01

78

Static pressure accelerates ox-LDL-induced cholesterol accumulation via SREBP-1-mediated caveolin-1 downregulation in cultured vascular smooth muscle cells  

SciTech Connect

Research highlights: {yields} Vertical static pressure accelerates ox-LDL-induced cholesterol accumulation in cultured vascular smooth muscle cells. {yields} Static pressure induces SREBP-1 activation. {yields} Static pressure downregulates the expressions of caveolin-1 by activating SREBP-1. {yields} Static pressure also downregulates the transcription of ABCA1 by activating SREBP-1. {yields} Static pressure increases ox-LDL-induced cholesterol accumulation by SREBP-1-mediated caveolin-1 downregulation in vascular smooth muscle cells cultured in vitro. -- Abstract: Objective: To investigate the effect of static pressure on cholesterol accumulation in vascular smooth muscle cells (VSMCs) and its mechanism. Methods: Rat-derived VSMC cell line A10 treated with 50 mg/L ox-LDL and different static pressures (0, 60, 90, 120, 150, 180 mm Hg) in a custom-made pressure incubator for 48 h. Intracellular lipid droplets and lipid levels were assayed by oil red O staining and HPLC; The mRNA levels of caveolin-1 and ABCA1, the protein levels of caveolin-1 SREBP-1 and mature SREBP-1 were respectively detected by RT-PCR or western blot. ALLN, an inhibitor of SREBP metabolism, was used to elevate SREBP-1 protein level in VSMCs treated with static pressure. Results: Static pressures significantly not only increase intracellular lipid droplets in VSMCs, but also elevate cellular lipid content in a pressure-dependent manner. Intracellular free cholesterol (FC), cholesterol ester (CE), total cholesterol (TC) were respectively increased from 60.5 {+-} 2.8 mg/g, 31.8 {+-} 0.7 mg/g, 92.3 {+-} 2.1 mg/g at atmosphere pressure (ATM, 0 mm Hg) to 150.8 {+-} 9.4 mg/g, 235.9 {+-} 3.0 mg/g, 386.7 {+-} 6.4 mg/g at 180 mm Hg. At the same time, static pressures decrease the mRNA and protein levels of caveolin-1, and induce the activation and nuclear translocation of SREBP-1. ALLN increases the protein level of mature SREBP-1 and decreases caveolin-1 expression, so that cellular lipid levels were upregulated. Conclusion: Static pressures stimulate ox-LDL-induced cholesterol accumulation in cultured VSMCs through decreasing caveolin-1 expression via inducing the maturation and nuclear translocation of SREBP-1.

Luo, Di-xian, E-mail: luodixian_2@163.com [Department of Pharmacology, School of Pharmaceutics, Central South University, Changsha 410083, Hunan (China) [Department of Pharmacology, School of Pharmaceutics, Central South University, Changsha 410083, Hunan (China); Institute of Pharmacy and Pharmacology, College of Science and Technology, University of South China, Hengyang 421001, Hunan (China); First People's Hospital of Chenzhou City, Chenzhou 423000, Hunan (China); Xia, Cheng-lai [Institute of Pharmacy and Pharmacology, College of Science and Technology, University of South China, Hengyang 421001, Hunan (China) [Institute of Pharmacy and Pharmacology, College of Science and Technology, University of South China, Hengyang 421001, Hunan (China); Department of Pharmacy, Third Affiliated Hospital Medical College of Guangzhou, Guangzhou 510150, Guangdong (China); Li, Jun-mu [Institute of Pharmacy and Pharmacology, College of Science and Technology, University of South China, Hengyang 421001, Hunan (China)] [Institute of Pharmacy and Pharmacology, College of Science and Technology, University of South China, Hengyang 421001, Hunan (China); Xiong, Yan [Department of Pharmacology, School of Pharmaceutics, Central South University, Changsha 410083, Hunan (China)] [Department of Pharmacology, School of Pharmaceutics, Central South University, Changsha 410083, Hunan (China); Yuan, Hao-yu [Institute of Pharmacy and Pharmacology, College of Science and Technology, University of South China, Hengyang 421001, Hunan (China) [Institute of Pharmacy and Pharmacology, College of Science and Technology, University of South China, Hengyang 421001, Hunan (China); Lusong Center for Disease Control and Prevention, Zhuzhou 412000, Hunan (China); TANG, Zhen-Wang; Zeng, Yixin [Institute of Pharmacy and Pharmacology, College of Science and Technology, University of South China, Hengyang 421001, Hunan (China)] [Institute of Pharmacy and Pharmacology, College of Science and Technology, University of South China, Hengyang 421001, Hunan (China); Liao, Duan-fang, E-mail: dfliao66@yahoo.com.cn [Institute of Pharmacy and Pharmacology, College of Science and Technology, University of South China, Hengyang 421001, Hunan (China) [Institute of Pharmacy and Pharmacology, College of Science and Technology, University of South China, Hengyang 421001, Hunan (China); Department of Traditional Chinese Diagnostics, School of Pharmacy, Hunan University of Chinese Medicine, Changsha 420108, Hunan (China)

2010-12-03

79

Changes in extracellular muscle volume affect heart rate and blood pressure responses to static exercise  

NASA Astrophysics Data System (ADS)

To investigate the effect of ?g-induced peripheral extracellular fluid reductions on heart rate and blood pressure during isometric exercise, six healthy male subjects performed three calf ergometer test with different extracellular volumes of working muscles. In all tests, body positions during exercise were identical (supine with the knee joint flexed to 900). After a pre-exercise period of 25 min, during which calf volumes were manipulated, subjects had to counteract an external force of 180 N for 5 min. During the pre-exercise period three different protocols were applied. Test A: Subjects rested in the exercise position; test B: Body position was the same as in A but calf volume was increased by venous congestion (cuffs inflated to 80 mm Hg); test C: Calf volumes were decreased by a negative hydrostatic pressure (calves about 40 cm above heart level with the subjects supine). To clamp the changed calf volumes in tests B and C, cuffs were inflated to 300 mm Hg 5 min before the onset of exercise. This occlusion was maintained until termination of exercise. Compared to tests A and B, the reduced volume of test C led to significant increases in heart rate and blood pressure during exercise. Oxygen uptake did not exceed resting levels in B and C until cuffs were deflated, indicating that exclusively calf muscles contributed to the neurogenic peripheral drive. It is concluded that changes in extracellular muscle volume have to be taken into account when comparing heart rate and blood pressure during lg- and ?g- exercise.

Baum, K.; Essfeld, D.; Stegemann, J.

80

Modified water solubility of milk protein concentrate powders through the application of static high pressure treatment.  

PubMed

The effects of high pressure (HP) treatment (100-400 MPa at 10-60 °C) on the solubility of milk protein concentrate (MPC) powders were tested. The solubility, measured at 20 °C, of fresh MPC powders made with no HP treatment was 66%. It decreased by 10% when stored for 6 weeks at ambient temperature (~20 °C) and continued to decrease to less than 50% of its initial solubility after 12 months of storage. Of the combinations of pressure and heat used, a pressure of 200 MPa at 40 °C applied to the concentrate before spray drying was found to be the most beneficial for improved solubility of MPC powders. This combination of pressure/heat improved the initial cold water solubility to 85%. The solubility was maintained at this level after 6 weeks storage at ambient temperature and 85% of the initial solubility was preserved after 12 months. The improved solubility of MPC powders on manufacture and on storage are attributed to an altered surface composition arising from an increased concentration of non-micellar casein in the milk due to HP treatment prior to drying. The improved solubility of high protein powders (95% protein) made from blends of sodium caseinate and whey protein isolate compared with MPC powders (~85% protein) made from ultrafiltered/diafiltered milk confirmed the detrimental role of micellar casein on solubility. The results suggest that increasing the non-micellar casein content by HP treatment of milk or use of blends of sodium caseinate and whey proteins are strategies that may be used to obtain high protein milk powders with enhanced solubility. PMID:22127220

Udabage, Punsandani; Puvanenthiran, Amirtha; Yoo, Jin Ah; Versteeg, Cornelis; Augustin, Mary Ann

2012-02-01

81

Analysis of Fluctuating Static Pressure Measurements in a Large High Reynolds Number Transonic Cryogenic Wind Tunnel. Ph.D. Thesis  

NASA Technical Reports Server (NTRS)

Dynamic measurements of fluctuating static pressure levels were made using flush mounted high frequency response pressure transducers at eleven locations in the circuit of the National Transonic Facility (NTF) over the complete operating range of this wind tunnel. Measurements were made at test section Mach numbers from 0.2 to 1.2, at pressure from 1 to 8.6 atmospheres and at temperatures from ambient to -250 F, resulting in dynamic flow disturbance measurements at the highest Reynolds numbers available in a transonic ground test facility. Tests were also made independently at variable Mach number, variable Reynolds number, and variable drivepower, each time keeping the other two variables constant thus allowing for the first time, a distinct separation of these three important variables. A description of the NTF emphasizing its flow quality features, details on the calibration of the instrumentation, results of measurements with the test section slots covered, downstream choke, effects of liquid nitrogen injection and gaseous nitrogen venting, comparisons between air and nitrogen, isolation of the effects of Mach number, Reynolds number, and fan drive power, and identification of the sources of significant flow disturbances is included. The results indicate that primary sources of flow disturbance in the NTF may be edge-tones generated by test section sidewall re-entry flaps and the venting of nitrogen gas from the return leg of the tunnel circuit between turns 3 and 4 in the cryogenic mode of operation. The tests to isolate the effects of Mach number, Reynolds number, and drive power indicate that Mach number effects predominate. A comparison with other transonic wind tunnels shows that the NTF has low levels of test section fluctuating static pressure especially in the high subsonic Mach number range from 0.7 to 0.9.

Igoe, William B.

1991-01-01

82

Quasi-statically growing crack-tip fields in elastic perfectly plastic pressure-sensitive materials under plane strain conditions  

Microsoft Academic Search

Quasi-statically growing crack-tip fields in elastic perfectly plastic pressure-sensitive materials under plane strain conditions\\u000a are investigated in this paper. The materials are assumed to follow the Drucker-Prager yield criterion and the normality flow\\u000a rule. The asymptotic mode I crack-tip fields are assumed to follow the five-sector assembly of Drugan et al. (1982) for Mises\\u000a materials. The crack-tip sectors, in turns,

W. j. Chang; M. Kim; J. Pan

1997-01-01

83

Static inflation and deflation pressure-volume curves from excised lungs of marine mammals  

PubMed Central

SUMMARY Excised lungs from eight marine mammal species [harp seal (Pagophilus groenlandicus), harbor seal (Phoca vitulina), gray seal (Halichoerus grypush), Atlantic white-sided dolphin (Lagenorhynchus acutus), common dolphin (Delphinus delphis), Risso's dolphin (Grampus griseus), long-finned pilot whale (Globicephala melas) and harbor porpoise (Phocoena phocoena)] were used to determine the minimum air volume of the relaxed lung (MAV, N=15), the elastic properties (pressure–volume curves, N=24) of the respiratory system and the total lung capacity (TLC). Our data indicate that mass-specific TLC (sTLC, l kg–1) does not differ between species or groups (odontocete vs phocid) and agree with that estimated (TLCest) from body mass (Mb) by applying the equation: TLCest=0.135 Mb0.92. Measured MAV was on average 7% of TLC, with a range from 0 to 16%. The pressure–volume curves were similar among species on inflation but diverged during deflation in phocids in comparison with odontocetes. These differences provide a structural basis for observed species differences in the depth at which lungs collapse and gas exchange ceases.

Fahlman, Andreas; Loring, Stephen H.; Ferrigno, Massimo; Moore, Colby; Early, Greg; Niemeyer, Misty; Lentell, Betty; Wenzel, Frederic; Joy, Ruth; Moore, Michael J.

2011-01-01

84

Failure of circular cylindrical shells formed from an orthotropic material, weakened by a longitudinal crack, and subjected to static loading by an axial force and internal pressure  

Microsoft Academic Search

References in which an alternate scheme of loading by internal pressure is preferentially analyzed are devoted to investigation of the limiting state of cracked shells fabricated from isotropic materials. Bastun and Galatenko and Bastun and Hretinin investigated the bearing capacity of circular cylindrical shells with a longitudinal crack under a combined static loading by an axial force and internal pressure.

V. N. Bastun

1995-01-01

85

Evaluation of static pressure drops and PM10 and TSP emissions for modified 1D-3D cyclones  

SciTech Connect

Five modifications of a standard 1D3D cyclone were tested and compared against the standard 1D3D design in the areas of particulate emissions and static pressure drop across the cyclone. The modifications to the 1D3D design included a 2D2D inlet, a 2D2D air outlet, a D/3 trash exit, an expansion chamber with a D/3 trash exit, and a tapered air outlet duct. The 1D3D modifications that exhibited a significant improvement in reducing both PM10 and total suspended particulate (TSP) emissions were the designs with the 2D2D inlet and air exhaust combined with either the conical D/3 tail cone or the expansion chamber. In reference to the standard 1D3D cyclone, the average reduction in PM10 emissions was 24 to 29% with a 29 to 35% reduction observed in TSP emissions. The modifications with the tapered air outlets did not show any significant improvements in controlling PM10 emissions. However, the modification with the tapered air outlet/expansion chamber combination exhibited statistical significance in reducing TSP emissions by 18% compared to the 1D3D cyclone. All modifications tested exhibited lower static pressure drops than the standard 1D3D.

Holt, G.A.; Baker, R.V.; Hughs, S.E.

1999-12-01

86

A dynamic nonlinear relationship between the static and pulsatile components of intracranial pressure in patients with subarachnoid hemorrhage  

PubMed Central

Object In the search for optimal monitoring and predictive tools in neurocritical care, the relationship of the pulsatile component of intracranial pressure (ICP) and the pressure itself has long been of great interest. Higher pressure often correlates with a higher pulsatile response to the heartbeat, interpreted as a type of compliance curve. Various mathematical approaches have been used, but regardless of the formula used, it is implicitly assumed that a reproducible curve exists. The authors investigated the stability of the correlation between static and pulsatile ICPs in patients with subarachnoid hemorrhage (SAH) who were observed for several hours by using data sets large enough to allow such calculations to be made. Methods The ICP recordings were obtained in 39 patients with SAH and were parsed into 6-second time windows (1,998,944 windows in 197 recordings). The ICP parameters were computed for each window as follows: static ICP was defined as the mean ICP, and pulsatile ICP was characterized by mean ICP wave amplitude, rise time, and rise time coefficient. Results The mean ICP and ICP wave amplitudes were simultaneously high or low (the expected correlation) in only ~ 60% of observations. Furthermore, static and pulsatile ICP correlated well only over short intervals; the degree of correlation weakened over periods of hours and was inconsistent across patients and within individual patients over time. Decorrelation originated with abrupt shifting and gradual drifting of mean ICP and ICP wave amplitude over several hours. Conclusions The relationship between the static and pulsatile components of ICPs changes over time. It evolves, even in individual patients, over a number of hours. This can be one reason the observation of high pulsatile ICP (indicative of reduced intracranial compliance) despite normal mean ICP that is seen in some patients with SAH. The meaning and potential clinical usefulness of such changes in the curves is uncertain, but it implies that clinical events result not only from moving further out on a compliance curve; in practice, the curve, and the biological system that underlies the curve, may itself change.

Eide, Per K.; Rapoport, Benjamin I.; Gormley, William B.; Madsen, Joseph R.

2014-01-01

87

Pressure Sores  

MedlinePLUS

Pressure sores are areas of damaged skin caused by staying in one position for too long. They commonly ... wheelchair, or are unable to change your position. Pressure sores can cause serious infections, some of which are ...

88

High Pressure.  

National Technical Information Service (NTIS)

A review is given of high-pressure research which touches on the following topics: Experimental techniques; Chemical kinetics and equilibria; Inorganic chemistry; Orientational disorder and related topics; High-pressure phases; Fluids.

E. Whalley

1967-01-01

89

Barometric pressure  

NASA Technical Reports Server (NTRS)

The effects of alterations in barometric pressure on human beings are described. Human tolerances for gaseous environments and low and high barometric pressure are discussed, including effects on specific areas, such as the ear, lungs, teeth, and sinuses. Problems due to trapped gas within the body, high dynamic pressures on the body, and blasts are also considered.

Billings, C. E.

1973-01-01

90

Feeling Pressured  

NSDL National Science Digital Library

In this activity, learners (at least three) work together to explore the effects of atmospheric pressure. A learner (at least 100 lbs) will step inside an extra large trash bag, while another reduces the air pressure in the bag slightly with a vacuum cleaner. The bag will squeeze the occupant due to the differences in external and internal pressure.

Muller, Eric

1998-01-01

91

Under Pressure  

NSDL National Science Digital Library

The contents of this chapter deal with air pressure and water pressure and what causes those things to increase and decrease. In addition, the real-world results of those increases and decreases in air and water pressure will be addressed.

Robertson, William C.

2005-01-01

92

Tuning the static spin-stripe phase and superconductivity in La2-xBaxCuO4 (x = 1/8) by hydrostatic pressure  

NASA Astrophysics Data System (ADS)

Magnetization and muon spin rotation experiments were performed in La2-xBaxCuO4 (x = 1/8) as a function of hydrostatic pressure up to p ? 2.2 GPa. It was found that the magnetic volume fraction of the static stripe phase strongly decreases linearly with pressure, while the superconducting volume fraction increases by the same amount. This demonstrates competition between bulk superconductivity and static magnetic order in the stripe phase of La1.875Ba0.125CuO4 and that these phenomena occur in mutually exclusive spatial regions. The present results also reveal that the static spin-stripe phase still exists at pressures, where the long-range low-temperature tetragonal (LTT) structure is completely suppressed. This indicates that the long-range LTT structure is not necessary for stabilizing the static spin order in La1.875Ba0.125CuO4.

Guguchia, Z.; Maisuradze, A.; Ghambashidze, G.; Khasanov, R.; Shengelaya, A.; Keller, H.

2013-09-01

93

Quasi-static compression of granular materials (sand) at high pressures (~3 GPA)  

NASA Astrophysics Data System (ADS)

This investigation presents the results on the static behavior of confined sand (from Eglin Air Force Base) subjected to axial compressive stresses up to 3 GPa. A self-aligning compression fixture was developed to statically compress sand specimen in a cylindrical steel confinement using tungsten carbide pins. A strain gage was mounted on the confining cylinder to measure the circumferential strain. Using axial stress, axial strain, and hoop strain the multi axial behavior of the confined sand is investigated. Compressive tests were conducted up to axial strains of 35%. The static response of the dry sand was tested at four different initial densities, namely, 1.55, 1.60, 1.65, and 1.75 g/cm 3. Effects of particle size, primarily classified as coarse and fine, were investigated. The effect of moisture was also investigated at four different degrees of saturation, namely, 0%, 20%, 40%, and 100%. The dense sand provided a much stiffer response than the loosely packed ones. The coarse sand grains showed significant crushing of particles followed by compaction of the powdered grains.

Subramanian, Vijay Krishnan

94

External Interference Effects of Flow Through Static-Pressure Orifices of an Airspeed Head at Several Supersonic Mach Numbers and Angles of Attack  

NASA Technical Reports Server (NTRS)

Wind-tunnel tests have been made to determine the static-pressure error resulting from external interference effects of flow through the static-pressure orifices of an NACA airspeed head at Mach numbers of 2.4, 3.0, and 4.0 for angles of attack of 0 deg, 5 deg, 10 deg, and 15 deg. Within the accuracy of the measurements and for the range of mass flow covered, the static-pressure error increased linearly with increasing mass-flow rate for both the forward and rear sets of orifices at all Mach numbers and angles of attack of the investigation. For a given value of flow coefficient, the static-pressure error varied appreciably with Mach number but only slightly with angle of attack. For example, for a flow coefficient out of the orifices of 0.01 (the approximate value for a vertically climbing airplane for which the airspeed system incorporates an airspeed meter, a Mach meter, and an altimeter), the error increased from about 5 percent to about 12 percent of the static pressure as the Mach number increased from 2.4 to 4.0 with the airspeed head at an angle of attack of 0 deg.

Silsby, Norman S.

1959-01-01

95

Static high pressure study of nitric oxide chemistry: proposed mechanism for nitric oxide detonation. [Shock initiated detonation  

SciTech Connect

The chemistry of nitric oxide under static high pressure conditions has been studied using diamond anvil cells and spectroscopic methods. Pressurized samples warmed rapidly to room temperature undergo facile disproportionation to form N/sub 2/O, N/sub 2/O/sub 3/, N/sub 2/O/sub 4/, and NO/sup +/NO/sub 3//sup -/. Nitric oxide maintained at 80 K is observed to react at ca. 2.5 GPa to form, dominantly, N/sub 2/, O/sub 2/, and NO/sup +/NO/sub 3//sup -/. The complex chemistry of nitric oxide is best explained in terms of two competing primary reaction mechanisms involving the direct formation of N/sub 2/ and O/sub 2/, and disproportionation to form N/sub 2/O and NO/sup +/NO/sub 3//sup -/. The disproportionation reaction, which is favored under higher temperature conditions, releases two-thirds of the total energy content, and is believed to be important in the early chemistry accompanying shock-initiation of nitric oxide. Laboratory scale detonation studies, where the gaseous products are analyzed spectroscopically, show evidence for, dominantly, disproportionation and a small amount of N/sub 2//O/sub 2/ production. This study points to the importance of condensed phase concerted reactions as well as ions and ionic reaction mechanisms in the shock initiated detonation of HE's. 14 refs., 3 figs., 1 tab.

Swanson, B.I.; Agnew, S.F.; Greiner, N.R.

1985-01-01

96

Under Pressure  

NSDL National Science Digital Library

In this experiment, learners examine how pressure affects water flow. In small groups, learners work with water and a soda bottle, and then relate their findings to pressure in the deep ocean. The printable six-page handout includes: a series of inquiry-based questions to get students thinking about pressure, both in the air and under water; illustrated experiment directions; and a worksheet that includes thought-provoking questions along with areas for recording experiment data.

History, American M.

2002-01-01

97

Pressure dependence of the static dielectric properties of K(H1-xDx)2PO4 and RbH2PO4  

Microsoft Academic Search

The effects of hydrostatic pressure on the static dielectric constant, ?c, Curie-Weiss constant, C, saturation polarization, Ps, and transition temperature, Ts, of the ferroelectrics K(H1-xDx)2PO4, and RbH2PO4 were investigated. The pressure dependence of Tc is known from earlier work and the present work extends the results to other deuterium concentrations, x; however, the results on C and Ps are largely

G. A. Samara

1978-01-01

98

Pressurized Sleeve  

NASA Technical Reports Server (NTRS)

Garment part sustains pressure differential without unduly restricting the user. Sleeve withstands pressure difference of 8 lb/in2 while allowing wearer fairly easy movement. Sleeve consists of low-torque joint hardware, sewn fabric sections, and lengthwise strips of fabric that restrain sections.

Lerner, Amy

1988-01-01

99

Under Pressure  

NSDL National Science Digital Library

This experiment, which can be completed in a single class period, examines how pressure affects water flow. In small groups, students work with water and a soda bottle, and then relate their findings to pressure in the deep ocean. The printable six-page handout includes a series of inquiry-based questions to get students thinking about pressure, both in the air and under water, illustrated experiment directions and a worksheet that includes thought-provoking questions along with areas for recording experiment data.

100

Measuring Pressure  

NSDL National Science Digital Library

Students learn first-hand the relationship between force, area and pressure. They use a force sensor built from a LEGO® MINDSTORMS® NXT kit to measure the force required to break through a paper napkin. An interchangeable top at the end of the force sensor enables testing of different-sized areas upon which to apply pressure. Measuring the force, and knowing the area, students compute the pressure. This leads to a concluding discussion on how these concepts are found and used in engineering and nature.

Applying Mechatronics to Promote Science (AMPS) Program GK-12,

101

Static and dynamic pressure measurements on a NACA 0012 airfoil in the Ames High Reynolds Number Facility  

NASA Technical Reports Server (NTRS)

The supercritical flows at high subsonic speeds over a NACA 0012 airfoil were studied to acquire aerodynamic data suitable for evaluating numerical-flow codes. The measurements consisted primarily of static and dynamic pressures on the airfoil and test-channel walls. Shadowgraphs were also taken of the flow field near the airfoil. The tests were performed at free-stream Mach numbers from approximately 0.7 to 0.8, at angles of attack sufficient to include the onset of buffet, and at Reynolds numbers from 1 million to 14 million. A test action was designed specifically to obtain two-dimensional airfoil data with a minimum of wall interference effects. Boundary-layer suction panels were used to minimize sidewall interference effects. Flexible upper and lower walls allow test-channel area-ruling to nullify Mach number changes induced by the mass removal, to correct for longitudinal boundary-layer growth, and to provide contouring compatible with the streamlines of the model in free air.

Mcdevitt, J. B.; Okuno, A. F.

1985-01-01

102

Pressure Activity  

NSDL National Science Digital Library

In this activity, students study the concept of atmospheric pressure and its role in generating winds and influencing day to day weather conditions. The activity consists of answering a set of questions by accessing keyword links to helper resources.

103

Pressure Sores  

MedlinePLUS

... Pressure sores should be kept covered with a bandage or dressing. Sometimes gauze is used. The gauze is kept ... at least once a day. Newer kinds of dressings include a see-through film and a hydrocolloid ...

104

Search for tricritical point in KH2PO4 at high pressure. I. Static dielectric behavior near critical point at zero pressure  

Microsoft Academic Search

The proposed tricritical point in KDP occurs if the critical field, Ecr, can be brought to zero by applying pressure. The Landau equation of state E = A0(T - T0)P + BP3 + CP5 gives straight-line “isopols” in the T-E plane. We obtain values for A0, B and C and thus Ecr by observing such isopols. We find A0 =

A. G. Baker; R. J. Pollina; V. H. Schmidt

1977-01-01

105

Flat Feet, Happy Feet? Comparison of the Dynamic Plantar Pressure Distribution and Static Medial Foot Geometry between Malawian and Dutch Adults  

PubMed Central

In contrast to western countries, foot complaints are rare in Africa. This is remarkable, as many African adults walk many hours each day, often barefoot or with worn-out shoes. The reason why Africans can withstand such loading without developing foot complaints might be related to the way the foot is loaded. Therefore, static foot geometry and dynamic plantar pressure distribution of 77 adults from Malawi were compared to 77 adults from the Netherlands. None of the subjects had a history of foot complaints. The plantar pressure pattern as well as the Arch Index (AI) and the trajectory of the center of pressure during the stance phase were calculated and compared between both groups. Standardized pictures were taken from the feet to assess the height of the Medial Longitudinal Arch (MLA). We found that Malawian adults: (1) loaded the midfoot for a longer and the forefoot for a shorter period during roll off, (2) had significantly lower plantar pressures under the heel and a part of the forefoot, and (3) had a larger AI and a lower MLA compared to the Dutch. These findings demonstrate that differences in static foot geometry, foot loading, and roll off technique exist between the two groups. The advantage of the foot loading pattern as shown by the Malawian group is that the plantar pressure is distributed more equally over the foot. This might prevent foot complaints.

Stolwijk, Niki M.; Duysens, Jacques; Louwerens, Jan Willem K.; van de Ven, Yvonne HM.; Keijsers, Noel LW.

2013-01-01

106

Pressure Interactions  

NSDL National Science Digital Library

This page allows you to change the state variables in the two ensembles and observe the interactions between the state variables. The piston mass is 50x the particles mass. This large piston mass produces a slow mechanical oscillation about the equal-pressure equilibrium point whenever a disequilibrium is created.

Christian, Wolfgang; Belloni, Mario

2008-02-09

107

Abnormal pressures as hydrodynamic phenomena  

USGS Publications Warehouse

So-called abnormal pressures, subsurface fluid pressures significantly higher or lower than hydrostatic, have excited speculation about their origin since subsurface exploration first encountered them. Two distinct conceptual models for abnormal pressures have gained currency among earth scientists. The static model sees abnormal pressures generally as relict features preserved by a virtual absence of fluid flow over geologic time. The hydrodynamic model instead envisions abnormal pressures as phenomena in which flow usually plays an important role. This paper develops the theoretical framework for abnormal pressures as hydrodynamic phenomena, shows that it explains the manifold occurrences of abnormal pressures, and examines the implications of this approach. -from Author

Neuzil, C. E.

1995-01-01

108

Pressurant requirements for discharge of liquid methane from a 1.52-meter-(5-ft-) diameter spherical tank under both static and slosh conditions  

NASA Technical Reports Server (NTRS)

Pressurized expulsion tests were conducted to determine the effect of various physical parameters on the pressurant gas (methane, helium, hydrogen, and nitrogen) requirements during the expulsion of liquid methane from a 1.52-meter-(5-ft-) diameter spherical tank and to compare results with those predicted by an analytical program. Also studied were the effects on methane, helium, and hydrogen pressurant requirements of various slosh excitation frequencies and amplitudes, both with and without slosh suppressing baffles in the tank. The experimental results when using gaseous methane, helium, and hydrogen show that the predictions of the analytical program agreed well with the actual pressurant requirements for static tank expulsions. The analytical program could not be used for gaseous nitrogen expulsions because of the large quantities of nitrogen which can dissolve in liquid methane. Under slosh conditions, a pronounced increase in gaseous methane requirements was observed relative to results obtained for the static tank expulsions. Slight decreases in the helium and hydrogen requirements were noted under similar test conditions.

Dewitt, R. L.; Mcintire, T. O.

1974-01-01

109

Pressure Alopecia  

PubMed Central

Postoperative or pressure alopecia (PA) is an infrequently reported group of scarring and non-scarring alopecias. It has been reported after immobilization of the head during surgery and following prolonged stays on intensive care units, and may be analogous to a healed pressure ulcer. This review presents a summary of cases published in pediatrics and after cardiac, gynecological, abdominal and facial surgeries. PA may manifest as swelling, tenderness, and ulceration of the scalp in the first few postoperative days; in other cases, the alopecia may be the presenting feature with a history of scalp immobilization in the previous four weeks. The condition may cause considerable psychological distress in the long term. Regular head turning schedules and vigilance for the condition should be used as prophylaxis to prevent permanent alopecia. A multi-center study in high-risk patients would be beneficial to shed further light on the etiology of the condition.

Davies, Kate E; Yesudian, PD

2012-01-01

110

Orifice plate and differential pressure measurement  

NASA Astrophysics Data System (ADS)

The dynamics of the static pressure in the inlet distance of the plus and minus sides of a standard orifice plate with direct connection to a piezoelectric pressure indicator and along differential pressure pipes were studied. The static pressure is due to vortices and cavitation in the pipe. The dynamics of the outlet signal of the differential pressure transmitter was measured. The high pressure behavior of volume and turbine gas meters and of rotary lobe meters is discussed.

Kerkmann, W.

1985-07-01

111

Pressurized hopper  

SciTech Connect

A Secure Automated Fuel Fabrication Line is being developed to reduce personnel exposure and to improve safeguards. Fertile and fissile fuel powders are blended in the line for making fuel pellets. A pressurized hopper was developed for use not only as a blender, but also as a storage and feeding device. It works with or without injection tubes to produce a well-blended powder with reduced agglomerate population. Results of blending experiments using dry Kaolin clay and Tempra pigment are given. (DLC)

Densley, P.J.; Goldmann, L.H. Jr.

1980-04-01

112

Measurements of Capillary Pressure-Saturation Relationships for Silica Sands Using Light Transmission Visualization and a Rapid Pseudo Static Methods  

EPA Science Inventory

Measurement of water saturation in porous media is essential for many types of studies including subsurface water flow, subsurface colloids transport and contaminant remediation to name a few. Water saturation (S) in porous media is dependent on the capillary pressure (Pc) which,...

113

Brine Flow Up a Borehole Caused by Pressure Perturbation From CO2 Storage: Static and Dynamic Evaluations  

EPA Science Inventory

Industrial-scale storage of CO2 in saline sedimentary basins will cause zones of elevated pressure, larger than the CO2 plume itself. If permeable conduits (e.g., leaking wells) exist between the injection reservoir and overlying shallow aquifers, brine could be pushed upwards al...

114

Brine flow up a well caused by pressure perturbation from geologic carbon sequestration: Static and dynamic evaluations  

Microsoft Academic Search

Industrial-scale storage of CO2 in saline sedimentary basins will cause zones of elevated pressure, larger than the CO2 plume itself. If permeable conduits (e.g., leaking wells) exist between the injection reservoir and overlying shallow aquifers, brine could be pushed upwards along these conduits and mix with groundwater resources. This paper discusses the potential for such brine leakage to occur in

Jens T. Birkholzer; Jean Philippe Nicot; Curtis M. Oldenburg; Quanlin Zhou; Stephen Kraemer; Karl Bandilla

2011-01-01

115

Round-robin pretest analyses of a 1:6-scale reinforced concrete containment model subject to static internal pressurization  

SciTech Connect

Analyses of a 1:6-scale reinforced concrete containment model that will be tested to failure at Sandia National Laboratories in the spring of 1987 were conducted by the following organizations in the United States and Europe: Sandia National Laboratories (USA), Argonne National Laboratory (USA), Electric Power Research Institute (USA), Commissariat a L'Energie Atomique (France), HM Nuclear Installations Inspectorate (UK), Comitato Nazionale per la ricerca e per lo sviluppo dell'Energia Nucleare e delle Energie Alternative (Italy), UK Atomic Energy Authority, Safety and Reliability Directorate (UK), Gesellschaft fuer Reaktorsicherheit (FRG), Brookhaven National Laboratory (USA), and Central Electricity Generating Board (UK). Each organization was supplied with a standard information package, which included construction drawings and actual material properties for most of the materials used in the model. Each organization worked independently using their own analytical methods. This report includes descriptions of the various analytical approaches and pretest predictions submitted by each organization. Significant milestones that occur with increasing pressure, such as damage to the concrete (cracking and crushing) and yielding of the steel components, and the failure pressure (capacity) and failure mechanism are described. Analytical predictions for pressure histories of strain in the liner and rebar and displacements are compared at locations where experimental results will be available after the test. Thus, these predictions can be compared to one another and to experimental results after the test.

Clauss, D.B. (ed.)

1987-05-01

116

The nonlinear anomalous lattice elasticity associated with the high-pressure phase transition in spodumene: a high-precision static compression study  

NASA Astrophysics Data System (ADS)

The high-pressure behavior of the lattice elasticity of spodumene, LiAlSi2O6, was studied by static compression in a diamond-anvil cell up to 9.3 GPa. Investigations by means of single-crystal XRD and Raman spectroscopy within the hydrostatic limits of the pressure medium focus on the pressure ranges around ~3.2 and ~7.7 GPa, which have been reported previously to comprise two independent structural phase transitions. While our measurements confirm the well-established first-order C2/ c- P21/ c transformation at 3.19 GPa (with 1.2% volume discontinuity and a hysteresis between 0.02 and 0.06 GPa), both unit-cell dimensions and the spectral changes observed in high-pressure Raman spectra give no evidence for structural changes related to a second phase transition. Monoclinic lattice parameters and unit-cell volumes at in total 59 different pressure points have been used to re-calculate the lattice-related properties of spontaneous strain, volume strain, and the bulk moduli as a function of pressure across the transition. A modified Landau free energy expansion in terms of a one component order parameter has been developed and tested against these experimentally determined data. The Landau solution provides a much better reproduction of the observed anomalies than any equation-of-state fit to data sets truncated below and above P tr, thus giving Landau parameters of K 0 = 138.3(2) GPa, K' = 7.46(5), ? V = 33.6(2) GPa, a = 0.486(3), b = -29.4(6) GPa and c = 551(11) GPa.

Ullrich, Angela; Schranz, Wilfried; Miletich, Ronald

2009-12-01

117

49 CFR 178.814 - Hydrostatic pressure test.  

Code of Federal Regulations, 2013 CFR

...that are loaded or discharged under pressure or intended to contain liquids...greater of: (A) The static pressure of the hazardous material on the...capacity; or (B) The static pressure of water on the bottom of the IBC...

2013-10-01

118

Understanding Blood Pressure Readings  

MedlinePLUS

Understanding Blood Pressure Readings Updated:May 15,2014 Blood pressure is typically recorded as two numbers, written as a ... blood). What is the AHA recommendation for healthy blood pressure? This chart reflects blood pressure categories defined ...

119

DIGITAL BLOOD PRESSURE MONITOR  

Microsoft Academic Search

In this work we present a blood pressure monitor which measures both the high blood pressure (systolic pressure), and the low blood pressure (diastolic pressure). It is a semiautomatic meter because the inflation of the occlusive cuff is carried out in a manual way. The transducer used is a piezoresistive silicon pressure sensor integrated on chip which provides a proportional

R. Fuentes; M. A. Bañuelos

2004-01-01

120

33 CFR 183.586 - Pressure impulse test.  

Code of Federal Regulations, 2010 CFR

...and Navigable Waters COAST GUARD...183.586 Pressure impulse test...pressure test under § 183.580...000 cycles of pressure impulse at...inert gas, or water. (g) Perform the static pressure test under §...

2009-07-01

121

33 CFR 183.586 - Pressure impulse test.  

Code of Federal Regulations, 2013 CFR

...and Navigable Waters COAST GUARD...183.586 Pressure impulse test...pressure test under § 183.580...000 cycles of pressure impulse at...inert gas, or water. (g) Perform the static pressure test under §...

2013-07-01

122

33 CFR 183.586 - Pressure impulse test.  

Code of Federal Regulations, 2010 CFR

...and Navigable Waters COAST GUARD...183.586 Pressure impulse test...pressure test under § 183.580...000 cycles of pressure impulse at...inert gas, or water. (g) Perform the static pressure test under §...

2010-07-01

123

Fracture resistance of welded thick-walled high-pressure vessels in power plants. Report No. 2. Approach to evaluating static strength  

SciTech Connect

The authors examine data on the effect of defects on the fracture resistance of high-pressure vessels and their models obtained within the framework of the HSST program. Results of internal-pressure tests of two types of vessels with a wall thickness of 152 mm made from forgings of steels SA508 and SA533, as well as small vessels with a wall thickness of 11.5 and 23mm made of steel SA533 are shown. The authors state that testing thick-walled welded high-pressure vessels and thin-walled vessels with surface defects of different sizes has demonstrated that there are substantial static-strength reserves in structures designed by existing domestic and foreign standards on the strength of power-plant equipment. A correction was proposed for the presently used method of calculating the resistance of highpressure vessels to brittle fracture that allows for the dimensions of the defects in relation to the type of vessel, the manufacturing technology, and the method of inspection.

Gorynin, I.V.; Filatov, V.M.; Ignatov, V.A.; Timofeev, B.T.; Zvezdin, Yu. I.

1986-07-01

124

A Technique for Measuring Unsteady Pressures.  

National Technical Information Service (NTIS)

A system for measuring unsteady pressures in flow fields employing a remote transducer and thin plastic pressure transmitting lines has been designed and built. The static and dynamic characteristics of the system were determined experimentally. The measu...

R. B. Johnson

1968-01-01

125

Simultaneous monitoring of static and dynamic intracranial pressure parameters from two separate sensors in patients with cerebral bleeds: comparison of findings  

PubMed Central

Background We recently reported that in an experimental setting the zero pressure level of solid intracranial pressure (ICP) sensors can be altered by electrostatics discharges. Changes in the zero pressure level would alter the ICP level (mean ICP); whether spontaneous changes in mean ICP happen in clinical settings is not known. This can be addressed by comparing the ICP parameters level and waveform of simultaneous ICP signals. To this end, we retrieved our recordings in patients with cerebral bleeds wherein the ICP had been recorded simultaneously from two different sensors. Materials and Methods: During a time period of 10?years, 17 patients with cerebral bleeds were monitored with two ICP sensors simultaneously; sensor 1 was always a solid sensor while Sensor 2 was a solid -, a fluid - or an air-pouch sensor. The simultaneous signals were analyzed with automatic identification of the cardiac induced ICP waves. The output was determined in consecutive 6-s time windows, both with regard to the static parameter mean ICP and the dynamic parameters (mean wave amplitude, MWA, and mean wave rise time, MWRT). Differences in mean ICP, MWA and MWRT between the two sensors were determined. Transfer functions between the sensors were determined to evaluate how sensors reproduce the ICP waveform. Results Comparing findings in two solid sensors disclosed major differences in mean ICP in 2 of 5 patients (40%), despite marginal differences in MWA, MWRT, and linear phase magnitude and phase. Qualitative assessment of trend plots of mean ICP and MWA revealed shifts and drifts of mean ICP in the clinical setting. The transfer function analysis comparing the solid sensor with either the fluid or air-pouch sensors revealed more variable transfer function magnitude and greater differences in the ICP waveform derived indices. Conclusions Simultaneous monitoring of ICP using two solid sensors may show marked differences in static ICP but close to identity in dynamic ICP waveforms. This indicates that shifts in ICP baseline pressure (sensor zero level) occur clinically; trend plots of the ICP parameters also confirm this. Solid sensors are superior to fluid – and air pouch sensors when evaluating the dynamic ICP parameters.

2012-01-01

126

High Blood Pressure (Hypertension)  

MedlinePLUS

... Women and Diabetes Heart Health for Women High Blood Pressure (Hypertension) Print and Share (PDF 109 KB) ... very sick or even die. What does high blood pressure do to your body? High blood pressure ...

127

High Blood Pressure  

MedlinePLUS

... normal blood pressure 140/90 or higher is high blood pressure Between 120 and 139 for the top number, ... prehypertension. Prehypertension means you may end up with high blood pressure, unless you take steps to prevent it. High ...

128

Dealing with Peer Pressure  

MedlinePLUS

... Let's talk about how to handle it. Defining Peer Pressure Peers influence your life, even if you don' ... with him. Why Do People Give in to Peer Pressure? Some kids give in to peer pressure because ...

129

Optically interrogated MEMS pressure sensor array  

Microsoft Academic Search

A novel pressure measurement technique is presented for wireless recording of time-averaged surface pressure distributions\\u000a in wind tunnel surveys. An array of silicon micro-plate resonators acts as pressure sensing element. The pressure is recorded\\u000a by measuring the sensor diaphragms’ resonance frequency using optical interferometry. Dependent on the quasi-static deflection\\u000a caused by a pressure load, the resonance frequency varies with an

Lukas ProchazkaAlexander; Alexander H. Meier; Antonio Viggiani; Thomas Roesgen

2011-01-01

130

Vapour pressure of diethyl phthalate  

Microsoft Academic Search

Measurements of vapour pressure in the liquid phase and of enthalpy of vaporisation and results of calculation of ideal-gas properties for diethyl phthalate are reported. The method of comparative ebulliometry, the static method, and the Knudsen mass-loss effusion method were employed to determine the vapour pressure. A Calvet-type differential microcalorimeter was used to measure the enthalpy of vaporisation. Simultaneous correlation

Vladislav Rohá?; Kv?toslav R?ži?ka; Vlastimil R?ži?ka; Dzmitry H. Zaitsau; Gennady J. Kabo; Vladimir Diky; Karel Aim

2004-01-01

131

Hydraulic Pressure Intensifier.  

National Technical Information Service (NTIS)

A hydraulic pressure intensifier is used to raise the pressure in an accumulator above a given input pressure. An oscillating piston provides a boost pressure while a pilot valve and a dump valve and restrictors allow the oscillating piston to move. (Auth...

R. S. Andrews

1985-01-01

132

Confusion about Pressure.  

ERIC Educational Resources Information Center

Listed are errors students make by accepting misconceptions about pressure and precautions teachers might take to avoid fostering those misconceptions. Misconceptions discussed include pressure as a measure of energy per unit volume, fluid flow only from high to low pressure, and the lack of pressures lower than a vacuum. (CW)

Kuethe, Dean O.

1991-01-01

133

Neural Network Burst Pressure Prediction in Composite Overwrapped Pressure Vessels  

NASA Technical Reports Server (NTRS)

Acoustic emission data were collected during the hydroburst testing of eleven 15 inch diameter filament wound composite overwrapped pressure vessels. A neural network burst pressure prediction was generated from the resulting AE amplitude data. The bottles shared commonality of graphite fiber, epoxy resin, and cure time. Individual bottles varied by cure mode (rotisserie versus static oven curing), types of inflicted damage, temperature of the pressurant, and pressurization scheme. Three categorical variables were selected to represent undamaged bottles, impact damaged bottles, and bottles with lacerated hoop fibers. This categorization along with the removal of the AE data from the disbonding noise between the aluminum liner and the composite overwrap allowed the prediction of burst pressures in all three sets of bottles using a single backpropagation neural network. Here the worst case error was 3.38 percent.

Hill, Eric v. K.; Dion, Seth-Andrew T.; Karl, Justin O.; Spivey, Nicholas S.; Walker, James L., II

2007-01-01

134

More About Pressure Probes For Turbulent Flows  

NASA Technical Reports Server (NTRS)

Array of probes yields data on static and total pressures and cross-stream turbulence. Is combination of separate pressure-probe arrays described in "Measuring Streamwise Momentum and Cross-Stream Turbulence" (ARC-11934), and "Probe Rakes To Measure Static Pressure and Turbulence" (ARC-12973). Equations that express directional responses of various probes in array solved together to eliminate unknown quantities; makes it possible to process digitized time-averaged probe readings together to obtain time-averaged static, stagnation, and cross-stream-turbulence pressures.

Rossow, Vernon J.

1995-01-01

135

What Causes Pressure?  

NSDL National Science Digital Library

In this kinesthetic activity that demonstrates pressure, learners act as air molecules in a "container" as defined by a rope. Learners explore how air molecules move in different scenarios: added pressure, reduced volume of the container, increased heat, etc. Learners will make "beeps" to help the group measure the pressure and hear the difference between low and high pressure. This is a great way to introduce the concept of air pressure and illustrate how it varies with density and temperature.

University, Colorado S.

2009-01-01

136

Constant-pressure blowers  

NASA Technical Reports Server (NTRS)

The conventional axial blowers operate on the high-pressure principle. One drawback of this type of blower is the relatively low pressure head, which one attempts to overcome with axial blowers producing very high pressure at a given circumferential speed. The Schicht constant-pressure blower affords pressure ratios considerably higher than those of axial blowers of conventional design with approximately the same efficiency.

Sorensen, E

1940-01-01

137

Pressure Dome for High-Pressure Electrolyzer  

NASA Technical Reports Server (NTRS)

A high-strength, low-weight pressure vessel dome was designed specifically to house a high-pressure [2,000 psi (approx. = 13.8 MPa)] electrolyzer. In operation, the dome is filled with an inert gas pressurized to roughly 100 psi (approx. = 690 kPa) above the high, balanced pressure product oxygen and hydrogen gas streams. The inert gas acts to reduce the clamping load on electrolyzer stack tie bolts since the dome pressure acting axially inward helps offset the outward axial forces from the stack gas pressure. Likewise, radial and circumferential stresses on electrolyzer frames are minimized. Because the dome is operated at a higher pressure than the electrolyzer product gas, any external electrolyzer leak prevents oxygen or hydrogen from leaking into the dome. Instead the affected stack gas stream pressure rises detectably, thereby enabling a system shutdown. All electrical and fluid connections to the stack are made inside the pressure dome and require special plumbing and electrical dome interfaces for this to be accomplished. Further benefits of the dome are that it can act as a containment shield in the unlikely event of a catastrophic failure. Studies indicate that, for a given active area (and hence, cell ID), frame outside diameter must become ever larger to support stresses at higher operating pressures. This can lead to a large footprint and increased costs associated with thicker and/or larger diameter end-plates, tie-rods, and the frames themselves. One solution is to employ rings that fit snugly around the frame. This complicates stack assembly and is sometimes difficult to achieve in practice, as its success is strongly dependent on frame and ring tolerances, gas pressure, and operating temperature. A pressure dome permits an otherwise low-pressure stack to operate at higher pressures without growing the electrolyzer hardware. The pressure dome consists of two machined segments. An O-ring is placed in an O-ring groove in the flange of the bottom segment and is trapped by the flange on the top dome segment when these components are bolted together with high-strength bolts. The pressure dome has several unique features. It is made (to ASME Pressure Vessel guidelines) in a high-strength aluminum alloy with the strength of stainless steel and the weight benefits of aluminum. The flange of the upper dome portion contains specially machined flats for mounting the dome, and other flats dedicated to the special feedthroughs for electrical connections. A pressure dome can be increased in length to house larger stacks (more cells) of the same diameter with the simple addition of a cylindrical segment. To aid in dome assembly, two stainless steel rings are employed. One is used beneath the heads of the high-strength bolts in lieu of individual hardened washers, and another is used instead of individual nuts. Like electrolyzers could be operated at low or high pressures simply by operating the electrolyzer outside or inside a pressurized dome.

Norman, Timothy; Schmitt, Edwin

2012-01-01

138

Short-pathlength, high-pressure flow cell for static and time-resolved infrared spectroscopy suitable for supercritical fluid solutions including hydrothermal systems  

Microsoft Academic Search

An optical flow cell for high pressures and temperatures is described. The use of a novel window design allows for a precise, fixed optical pathlength that can be varied by use of spacers that range from a few micrometers to several millimeters. The cell pathlength is not affected by changes in pressure or temperature. The novel window design may be

Markus M. Hoffmann; R. Shane Addleman; John L. Fulton

2000-01-01

139

External pressure measurement system  

NASA Astrophysics Data System (ADS)

Hydraulic systems comprise an important part of jet aircraft and their pressure needs must be checked constantly. Tests of the prototype external pressure measurement system show that it is possible to accurately convert the small expansion of tubing with pressure into a direct pressure reading without inserting a pressure gage into the piping system. The tool described in the paper is a clamp-on displacement transducer that can read pressure directly in PSI from 0 to 5000. Some limitations concerning temperature and accuracy should be remedied by additional design work. The system promises to streamline troubleshooting of all types of piping systems.

Chandler, Jon K.; Fowler, Don P.

140

Air flow and pressure inside a pressure-swirl spray and their effects on spray development  

SciTech Connect

Air flow and pressure inside a pressure-swirl spray for direct injection (DI) gasoline engines and their effects on spray development have been analyzed at different injector operating conditions. A simulation tool was utilized and the static air pressure at the centerline of the spray was measured to investigate the static pressure and flow structure inside the swirl spray. To investigate the effect of static air pressure on swirl spray development, a liquid film model was applied and the Mie-scattered images were captured. The simulation and experiment showed that recirculation vortex and air pressure drop inside the swirl spray were observable and the air pressure drop was greater at high injection pressure. At high fuel temperature, the air pressure at the nozzle exit showed higher value compared to the atmospheric pressure and then continuously decreased up to few millimeters distance from the nozzle exit. The pressure drop at high fuel temperatures was more than that of atmospheric temperature. This reduced air pressure was recovered to the atmospheric pressure at further downstream. The results from the liquid film model and macroscopic spray images showed that the air pressure started to affect the liquid film trajectory about 3 mm from the nozzle exit and this effect was sustained until the air pressure recovered to the atmospheric pressure. However, the entrained air motion and droplet size have more significant influence on the spray development after the most of the liquid sheet is broken-up and the spray loses its initial momentum. (author)

Moon, Seoksu; Bae, Choongsik [Department of Mechanical Engineering, Korea Advanced Institute of Science and Technology, Guseong-dong, Yuseong-gu, Daejon 305-701 (Korea); Abo-Serie, Essam [Department of Mechanical Engineering and Design, Coventry University, Priory Street, Coventry CV1 5FB (United Kingdom)

2009-01-15

141

Flutter spectral measurements using stationary pressure transducers  

NASA Technical Reports Server (NTRS)

Engine-order sampling was used to eliminate the integral harmonics from the flutter spectra corresponding to a case-mounted static pressure transducer. Using the optical displacement data, it was demonstrated that the blade-order sampling of pressure data may yield erroneous results due to the interference caused by blade vibration. Two methods are presented which effectively eliminate this interference yielding the blade-pressure-difference spectra. The phase difference between the differential-pressure and the displacement spectra was evaluated.

Kurkov, A. P.

1980-01-01

142

The Root Pressure Phenomenon  

ERIC Educational Resources Information Center

Describes experiments demonstrating that root pressure in plants is probably controlled by a circadian rhythm (biological clock). Root pressure phenomenon plays significant part in water transport in contradiction with prevalent belief. (PS)

Marsh, A. R.

1972-01-01

143

Pressure Sensitive Paints  

NASA Technical Reports Server (NTRS)

This article reviews new advances and applications of pressure sensitive paints in aerodynamic testing. Emphasis is placed on important technical aspects of pressure sensitive paint including instrumentation, data processing, and uncertainty analysis.

Liu, Tianshu; Bencic, T.; Sullivan, J. P.

1999-01-01

144

Fluid Pressure Calculator  

NSDL National Science Digital Library

Solve for different variables related to force, area, bulk modulus, compressibility, change in volume, fluid column top and bottom pressure, density, acceleration of gravity, depth, height, absolute, atmospheric and gauge pressure.

Raymond, Jimmy

145

Blood Pressure Medicines  

MedlinePLUS

... reducing sodium in your diet, you may need medicines. Blood pressure medicines work in different ways to lower blood pressure. ... and widen blood vessels. Often, two or more medicines work better than one. NIH: National Heart, Lung, ...

146

Pressure-sensitive optrode  

DOEpatents

An apparatus is provided for sensing changes in pressure and for generating optical signals related to said changes in pressure. Light from a fiber optic illuminates a fluorescent composition causing it to fluoresce. The fluorescent composition is caused to more relative to the end of the fiber optic in response to changes in pressure so that the intensity of fluorescent emissions collected by the same fiber optic used for illumination varies monotonically with pressure.

Hirschfeld, Tomas B. (Livermore, CA) [Livermore, CA

1986-01-01

147

Portable Potable Pressure  

NSDL National Science Digital Library

In this activity, learners use plastic water bottles, wood, and water to build an inexpensive and portable tool to demonstrate one atmosphere of pressure at sea level. Once the tool is assembled learners use it to explore atmospheric pressure and how humans respond to this pressure on Earth. This resource includes optional extensions to investigate non-metric units and atmospheric pressure on Venus, Mars, and in the deep ocean.

Muller, Eric

2004-01-01

148

Negative Pressure Ventilation  

Microsoft Academic Search

\\u000a In essence, the negative pressure ventilator comprises a rigid shell that partly or completely encloses the patient’s torso,\\u000a the pressure within which can be dropped by means of an attached pump.27 Air enters the lungs as a result of the fall in pleural pressure produced by expansion of the thoracic cage. Expiration is\\u000a passive. Negative pressure ventilators were introduced in

Ashfaq Hasan

149

A Shot Under Pressure  

NSDL National Science Digital Library

Students use their understanding of projectile physics and fluid dynamics to find the water pressure in water guns. By measuring the range of the water jets, they are able to calculate the theoretical pressure. Students create graphs to analyze how the predicted pressure relates to the number of times they pump the water gun before shooting.

Integrated Teaching And Learning Program

150

Dilatometry under high pressure  

Microsoft Academic Search

In order to measure anisotropic compressibilities and thermal expansion of cubic, tetragonal or orthorhombic single crystals under pressure we have miniaturized a high resolution capacitive dilatometer and integrated this device in a high pressure cell within a cryostat which allows a temperature variation from 10 K to 320 K. To minimize the number of electrical lead-throughs from ambient pressure to

Walter H. Fietz; Kai Grube; Hanno Leibrock

2000-01-01

151

Optional Barometric Pressure Protocol  

NSDL National Science Digital Library

The purpose of this activity is to measure air pressure. Students record atmospheric pressure using a barometer or altimeter. Intended outcomes are that students gain an understanding that barometric or altimeter pressure varies and its increase or decrease indicates an upcoming change in the weather. Students also learn that the air has weight. Supporting background materials for both student and teacher are included.

The GLOBE Program, UCAR (University Corporation for Atmospheric Research)

2003-08-01

152

Piezoresonant pressure sensors  

Microsoft Academic Search

Piezoresonant pressure sensors based on existing commercially produced high frequency thermostable piezoelements are described. The possibility of developing a design series of piezoresonant pressure sensors operating in the 0.1 to 600 kPa range for measuring atmospheric pressure in enclosed spaces is examined. The use of a piezoresonator in a self sustained oscillator circuit makes it possible to obtain a signal

L. V. Maleyko; V. V. Malov; A. P. Rudenkov; I. V. Yakovlev; T. B. Ibragimov; V. A. Maglysh; O. F. Migukina; Pitkevich

1986-01-01

153

High pressure ices  

PubMed Central

H2O will be more resistant to metallization than previously thought. From computational evolutionary structure searches, we find a sequence of new stable and meta-stable structures for the ground state of ice in the 1–5 TPa (10 to 50 Mbar) regime, in the static approximation. The previously proposed Pbcm structure is superseded by a Pmc21 phase at p = 930 GPa, followed by a predicted transition to a P21 crystal structure at p = 1.3 TPa. This phase, featuring higher coordination at O and H, is stable over a wide pressure range, reaching 4.8 TPa. We analyze carefully the geometrical changes in the calculated structures, especially the buckling at the H in O-H-O motifs. All structures are insulating—chemistry burns a deep and (with pressure increase) lasting hole in the density of states near the highest occupied electronic levels of what might be component metallic lattices. Metallization of ice in our calculations occurs only near 4.8 TPa, where the metallic C2/m phase becomes most stable. In this regime, zero-point energies much larger than typical enthalpy differences suggest possible melting of the H sublattice, or even the entire crystal.

Hermann, Andreas; Ashcroft, N. W.; Hoffmann, Roald

2012-01-01

154

Pressure ulcer prevention.  

PubMed

The purpose of this collective review is to outline the predisposing factors in the development of pressure ulcers and to identify a pressure ulcer prevention program. The most frequent sites for pressure ulcers are areas of skin overlying bony prominences. There are four critical factors contributing to the development of pressure ulcers: pressure, shearing forces, friction, and moisture. Pressure is now viewed as the single most important etiologic factor in pressure ulcer formation. Prolonged immobilization, sensory deficit, circulatory disturbances, and poor nutrition have been identified as important risk factors in the development of pressure ulcer formation. Among the clinical assessment scales available, only two, the Braden Scale and Norton Scale, have been tested extensively for reliability and/or validity. The most commonly used risk assessment tools for pressure ulcer formation are computerized pressure monitoring and measurement of laser Doppler skin blood flow. Pressure ulcers can predispose the patient to a variety of complications that include bacteremia, osteomyelitis, squamous cell carcinoma, and sinus tracts. The three components of pressure ulcer prevention that must be considered in any patient include management of incontinence, nutritional support, and pressure relief. The pressure relief program must be individualized for non-weight-bearing individuals as well as those that can bear weight. For those that can not bear weight and passively stand, the RENAISSANCE Mattress Replacement System is recommended for the immobile patient who lies supine on the bed, the stretcher, or operating room table. This alternating pressure system is unique because it has three separate cells that are not interconnected. It is specifically designed so that deflation of each individual cell will reach a ZERO PRESSURE during each alternating pressure cycle. The superiority of this system has been documented by comprehensive clinical studies in which this system has been compared to the standard hospital bed as well as to two other commercially available pressure relief mattresses. The most recent advance in pressure ulcer prevention is the development of the ALTERN8* seating system. This seating system provides regular periods of pressure relief and stimulation of blood flow to skin areas while users are seated. By offering the combination of pressure relief therapy and an increase in blood flow, the ALTERN8* reportedly creates an optimum pressure ulcer healing environment. Foam is the most commonly used material for pressure reduction and pressure ulcer prevention and treatment for the mobile individual. For those immobilized individuals who can achieve a passive standing position, a powered wheelchair that allows the individual to achieve a passive standing position is recommended. The beneficial effects of passive standing have been documented by comprehensive scientific studies. These benefits include reduction of seating pressure, decreased bone demineralization, increased blander pressure, enhanced orthostatic circulatory regulation, reduction in muscular tone, decrease in upper extremity muscle stress, and enhanced functional status in general. In the absence of these dynamic alternating pressure seating systems and mattresses, there are enormous medicolegal implications to the healthcare facility. Because there is not sufficient staff to provide pressure relief to rotate the patient every 2 hours in a hospital setting, with the exception of the intensive care unit, the immobile patient is prone to develop pressure ulcers. The cost of caring for these preventable pressure ulcers may now be as high as 60,000 dollars per patient. The occupational physical strain sustained by nursing personnel in rotating their patients has led to occupational back pain in nurses, a major source of morbidity in the healthcare environment. PMID:15447627

Edlich, Richard F; Winters, Kathryne L; Woodard, Charles R; Buschbacher, Ralph M; Long, William B; Gebhart, Jocelynn H; Ma, Eva K

2004-01-01

155

Gravastars must have anisotropic pressures  

NASA Astrophysics Data System (ADS)

One of the very small number of serious alternatives to the usual concept of an astrophysical black hole is the 'gravastar' model developed by Mazur and Mottola, and a related phase-transition model due to Laughlin et al. We consider a generalized class of similar models that exhibit continuous pressure—without the presence of infinitesimally thin shells. By considering the usual TOV equation for static solutions with negative central pressure, we find that gravastars cannot be perfect fluids—anisotropic pressures in the 'crust' of a gravastar-like object are unavoidable. The anisotropic TOV equation can then be used to bound the pressure anisotropy. The transverse stresses that support a gravastar permit a higher compactness than is given by the Buchdahl Bondi bound for perfect-fluid stars. Finally, we comment on the qualitative features of the equation of state that gravastar material must have if it is to do the desired job of preventing horizon formation.

Cattoen, Celine; Faber, Tristan; Visser, Matt

2005-10-01

156

Fracture resistance of welded thick-walled high-pressure vessels in power plants. Report No. 2. Approach to evaluating static strength  

Microsoft Academic Search

The authors examine data on the effect of defects on the fracture resistance of high-pressure vessels and their models obtained within the framework of the HSST program. Results of internal-pressure tests of two types of vessels with a wall thickness of 152 mm made from forgings of steels SA508 and SA533, as well as small vessels with a wall thickness

I. V. Gorynin; V. M. Filatov; V. A. Ignatov; B. T. Timofeev; Yu. I. Zvezdin

1986-01-01

157

Dynamic Pressure Calibration Standard  

NASA Technical Reports Server (NTRS)

Vibrating columns of fluid used to calibrate transducers. Dynamic pressure calibration standard developed for calibrating flush diaphragm-mounted pressure transducers. Pressures up to 20 kPa (3 psi) accurately generated over frequency range of 50 to 1,800 Hz. System includes two conically shaped aluminum columns one 5 cm (2 in.) high for low pressures and another 11 cm (4.3 in.) high for higher pressures, each filled with viscous fluid. Each column mounted on armature of vibration exciter, which imparts sinusoidally varying acceleration to fluid column. Signal noise low, and waveform highly dependent on quality of drive signal in vibration exciter.

Schutte, P. C.; Cate, K. H.; Young, S. D.

1986-01-01

158

Pressure reducing regulator  

DOEpatents

A pressure reducing regulator that controls its downstream or outlet pressure to a fixed fraction of its upstream or inlet pressure. The regulator includes a housing which may be of a titanium alloy, within which is located a seal or gasket at the outlet end which may be made of annealed copper, a rod, and piston, each of which may be made of high density graphite. The regulator is insensitive to temperature by virtue of being without a spring or gas sealed behind a diaphragm, and provides a reference for a system in which it is being used. The rod and piston of the regulator are constructed, for example, to have a 1/20 ratio such that when the downstream pressure is less than 1/20 of the upstream pressure the regulator opens and when the downstream pressure exceeds 1/20 of the upstream pressure the regulator closes.

Whitehead, John C. (Davis, CA); Dilgard, Lemoyne W. (Willits, CA)

1995-01-01

159

An electrokinetic pressure sensor  

NASA Astrophysics Data System (ADS)

A new concept for a micro pressure sensor is demonstrated. The pressure difference between the inlet and the outlet of glass nanochannels is obtained by measuring the electrokinetically generated electric potential. To demonstrate the proposed concept, experimental investigations are performed for 100 nm wide nanochannels with sodium chloride solutions having various concentrations. The proposed pressure sensor is able to measure the pressure difference within a 10% deviation from linearity. The sensitivity of the electrokinetic pressure sensor with 10-5 M sodium chloride solution is 18.5 µV Pa-1, which is one order of magnitude higher than that of typical diaphragm-based pressure sensors. A numerical model is presented for investigating the effects of the concentration and the channel width on the sensitivity of the electrokinetic pressure sensor. Numerical results show that the sensitivity increases as the concentration decreases and the channel width increases.

Kim, Dong-Kwon; Kim, Duckjong; Kim, Sung Jin

2008-05-01

160

Pressure regulating valve controller  

SciTech Connect

In an aircraft cabin air conditioning system comprising a pair of air cycle refrigeration systems which provide chilled air to the cabin, airflow through the air cycle refrigeration systems being controllable by a pair of pressure regulating valves, each of the pressure regulating valves being disposed in a corresponding main airflow conduit and operated by a corresponding pneumatic valve actuator, the improvement is described by: one of the pneumatic valve actuators associated with one of the pressure regulating valves being operated by a controller comprising: a main servo conduit communicating with one of the main airflow conduits and the pneumatic valve actuator for channeling pneumatic pressure thereto from the main airflow; a first pressure regulator communicating with the main servo conduit for continuously adjusting pneumatic pressure therewithin in response to ram air temperature; a second pressure regulator communicating with the main servo conduit for providing step function adjustment in pneumatic pressure; and means communicating with the main servo conduit for overriding the second pressure regulator to effect partial closing of the one pressure regulating valve despite the deactivation of the air cycle system.

Goodman, R.B.

1988-04-05

161

Study of the laser-induced decomposition of energetic materials at static high-pressure by time-resolved absorption spectroscopy  

NASA Astrophysics Data System (ADS)

The reactivity of laser-initiated energetic materials has been studied at high-pressure using time-resolved absorption spectroscopy in a diamond anvil cell (DAC). The results obtained for nitromethane (NM) are presented in this paper. A change in reactivity is clearly seen around 25 GPa. Below this pressure, a one-step reaction is found to occur. The decomposition products formed behind the combustion front are essentially carbon residues as shown by Raman spectroscopy. At higher pressure, a two-step mechanism is observed. The first step, which is similar to the reaction observed below 25 GPa, leads to the formation of carbonaceous products. It is followed by a slower step which leads to the formation of a transparent amorphous product. This product remains stable in the DAC after reaction.

Hébert, P.; Saint-Amans, C.

2014-05-01

162

Pressure cryocooling protein crystals  

DOEpatents

Preparation of cryocooled protein crystal is provided by use of helium pressurizing and cryocooling to obtain cryocooled protein crystal allowing collection of high resolution data and by heavier noble gas (krypton or xenon) binding followed by helium pressurizing and cryocooling to obtain cryocooled protein crystal for collection of high resolution data and SAD phasing simultaneously. The helium pressurizing is carried out on crystal coated to prevent dehydration or on crystal grown in aqueous solution in a capillary.

Kim, Chae Un (Ithaca, NY); Gruner, Sol M. (Ithaca, NY)

2011-10-04

163

A pressure electrolyzer unit  

Microsoft Academic Search

Summary  An electrolytic cell has been built for filling pressure cylinders with deuterium at high pressure. The bottles are filled\\u000a directly from the cell using the electrolytic liberating pressure of D2 and O2. The levels of the electrolyte are held constant by means of an electromagnetically operated leak, controlled by the current\\u000a through the electrolytic cell.

Jan Flinta

1955-01-01

164

A pressure electrolyzer unit  

Microsoft Academic Search

Summary  An electrolytic cell has been built for filling pressure cylinders with deuterium at high pressure. The bottles are filled\\u000a directly from the cell using the electrolytic liberating pressure of D2 and O2. The levels of the electrolyte are held constant by means of an electromagnetically operated leak, controlled by the current\\u000a through the electrolytic cell.

Jan Flinta

1953-01-01

165

Attachment Fitting for Pressure Vessel  

NASA Technical Reports Server (NTRS)

This invention provides sealed access to the interior of a pressure vessel and consists of a tube. a collar, redundant seals, and a port. The port allows the seals to be pressurized and seated before the pressure vessel becomes pressurized.

Smeltzer, Stanley S., III (Inventor); Carrigan, Robert W. (Inventor)

2002-01-01

166

Living with High Blood Pressure  

MedlinePLUS

... page from the NHLBI on Twitter. Living With High Blood Pressure If you have high blood pressure ( ... If You Have High Blood Pressure Web page. High Blood Pressure and Pregnancy Many pregnant women who ...

167

JAMA Patient Page: Pressure Ulcers  

MedlinePLUS

... of the American Medical Association JAMA PATIENT PAGE Pressure Ulcers A pressure ulcer is an injury to the skin as a ... call 203/259-8724. PREVENTION AND TREATMENT OF PRESSURE ULCERS Prevention of pressure ulcers is key because treatment ...

168

CC Pressure Test  

SciTech Connect

The inner vessel heads including bypass and beam tubes had just been welded into place and dye penetrant checked. The vacuum heads were not on at this time but the vacuum shell was on covering the piping penetrating into the inner vessel. Signal boxes with all feed through boards, the instrumentation box, and high voltage boxes were all installed with their pump outs capped. All 1/4-inch instrumentation lines were terminated at their respective shutoff valves. All vacuum piping used for pumping down the inner vessel was isolated using o-ring sealed blind flanges. PV215A (VAT Series 12), the 4-inch VRC gate valve isolating the cyropump, and the rupture disk had to be removed and replaced with blind flanges before pressurizing due to their pressure limitations. Stresses in plates used as blind flanges were checked using Code calcualtions. Before the CC test, vacuum style blanks and clamps were hydrostatically pressure tested to 150% of the maximum test pressure, 60 psig. The Code inspector and Research Division Safety had all given their approval to the test pressure and procedure prior to filling the vessel with argon. The test was a major success. Based on the lack of any distinguishable pressure drop indicated on the pressure gages, the vessel appeared to be structurally sound throughout the duration of the test (approx. 3 hrs.). A major leak in the instrumentation tubing was discovered at half of the maximum test pressure and was quickly isolated by crimping and capping with a compression fitting. There were some slight deviations in the actual procedure used. The 44 psig relief valve located just outside the cleanroom had to be capped until the pressure in the vessel indicated 38 psi. This was to allow higher supply pressures and hence, higher flows through the pressurizing line. Also, in order to get pressure readings at the cryostat without exposing any personnel to the potentially dangerous stored energy near the maximum test pressure, a camera was installed at the top of the vessel to view the indicator mounted there. The monitor was viewed at the ante room adjacent to the cleanroom. The holding pressure of 32 psig (4/5 of the maximum test pressure) was only maintained for about 20 minutes instead of the half hour recommendation in the procedure. We felt that this was sufficient time to Snoop test and perform the pressure drop test. After the test was completed, the inspector for CBI Na-Con and the Research Divison Safety Officer signed all of required documentation.

Dixon, K.; /Fermilab

1990-07-12

169

Pressure-sensitive optrode  

DOEpatents

Apparatus and method for sensing changes in pressure and for generating optical signals related to changes in pressure. Light from a fiber optic is directed to a movable surface which is coated with a light-responsive material, and which moves relative to the end of the fiber optic in response to changes in pressure. The same fiber optic collects a portion of the reflected or emitted light from the movable surface. Changes in pressure are determined by measuring changes in the amount of light collected.

Hirschfeld, Tomas B. (Livermore, CA)

1985-01-01

170

Sapphire tube pressure vessel  

DOEpatents

A pressure vessel is provided for observing corrosive fluids at high temperatures and pressures. A transparent Teflon bag contains the corrosive fluid and provides an inert barrier. The Teflon bag is placed within a sapphire tube, which forms a pressure boundary. The tube is received within a pipe including a viewing window. The combination of the Teflon bag, sapphire tube and pipe provides a strong and inert pressure vessel. In an alternative embodiment, tie rods connect together compression fittings at opposite ends of the sapphire tube.

Outwater, John O. (Cambridge, MA)

2000-01-01

171

Pressurized fluidized bed reactor  

DOEpatents

A pressurized fluid bed reactor power plant includes a fluidized bed reactor contained within a pressure vessel with a pressurized gas volume between the reactor and the vessel. A first conduit supplies primary gas from the gas volume to the reactor, passing outside the pressure vessel and then returning through the pressure vessel to the reactor, and pressurized gas is supplied from a compressor through a second conduit to the gas volume. A third conduit, comprising a hot gas discharge, carries gases from the reactor, through a filter, and ultimately to a turbine. During normal operation of the plant, pressurized gas is withdrawn from the gas volume through the first conduit and introduced into the reactor at a substantially continuously controlled rate as the primary gas to the reactor. In response to an operational disturbance of the plant, the flow of gas in the first, second, and third conduits is terminated, and thereafter the pressure in the gas volume and in the reactor is substantially simultaneously reduced by opening pressure relief valves in the first and third conduits, and optionally by passing air directly from the second conduit to the turbine.

Isaksson, Juhani (Karhula, FI)

1996-01-01

172

Pressurized fluidized bed reactor  

DOEpatents

A pressurized fluid bed reactor power plant includes a fluidized bed reactor contained within a pressure vessel with a pressurized gas volume between the reactor and the vessel. A first conduit supplies primary gas from the gas volume to the reactor, passing outside the pressure vessel and then returning through the pressure vessel to the reactor, and pressurized gas is supplied from a compressor through a second conduit to the gas volume. A third conduit, comprising a hot gas discharge, carries gases from the reactor, through a filter, and ultimately to a turbine. During normal operation of the plant, pressurized gas is withdrawn from the gas volume through the first conduit and introduced into the reactor at a substantially continuously controlled rate as the primary gas to the reactor. In response to an operational disturbance of the plant, the flow of gas in the first, second, and third conduits is terminated, and thereafter the pressure in the gas volume and in the reactor is substantially simultaneously reduced by opening pressure relief valves in the first and third conduits, and optionally by passing air directly from the second conduit to the turbine. 1 fig.

Isaksson, J.

1996-03-19

173

Pressure-sensitive optrode  

DOEpatents

An apparatus and method are disclosed for sensing changes in pressure and for generating optical signals related to changes in pressure. Light from a fiber optic is directed to a movable surface which is coated with a light-responsive material, and which moves relative to the end of the fiber optic in response to changes in pressure. The same fiber optic collects a portion of the reflected or emitted light from the movable surface. Changes in pressure are determined by measuring changes in the amount of light collected. 5 figs.

Hirschfeld, T.B.

1985-04-09

174

Putting on the Pressure  

NSDL National Science Digital Library

Students build a simple aneroid barometer that can be used to measure changes in air pressure. Materials required include a large jar, ruler, large balloon, 2 drinking straws, and clay. The instrument is used to track changes in air pressure, and students observe that sunny days usually have higher pressure and rainy days have lower pressure. The resource is part of the teacher's guide accompanying the video, NASA SCI Files: The Case of the Phenomenal Weather. Lesson objectives supported by the video, additional resources, teaching tips and an answer sheet are included in the teacher's guide.

175

Pressure Dependence of Plasma Actuated Flow Control  

NASA Astrophysics Data System (ADS)

An experimental investigation was conducted to determine how Single Dielectric-Barrier Discharge (SDBD) plasma actuators performed under variable ambient pressure. The static pressure was varied from 0.17 to 9.0 bar. The plasma initiation voltage and static thrust were measured and compared to similar data in literature. The results showed that at a given pressure, the plasma initiation voltage scaled with the actuator capacitor per unit area. The measured thrust showed the previously observed power-law relation with voltage, but the exponent varied with pressure. These trends were evaluated against simulations from the SDBD Space-Time Lumped Element Model. Parameters in the model affected by ambient pressure (capacitance, resistance, and Debye length of the air) were then systematically investigated to determine their effects on the plasma-produced body force. The overall trends were best modeled through a pressure dependence of the Debye length.

Valerioti, Joseph; Corke, Thomas

2010-11-01

176

Dual shell pressure balanced vessel  

DOEpatents

A dual-wall pressure balanced vessel for processing high viscosity slurries at high temperatures and pressures having an outer pressure vessel and an inner vessel with an annular space between the vessels pressurized at a pressure slightly less than or equivalent to the pressure within the inner vessel.

Fassbender, Alexander G. (West Richland, WA)

1992-01-01

177

High-pressure science and technology--1993  

Microsoft Academic Search

These proceedings represent papers presented at the joint meeting of the International Association for Research and Advancement of High Pressure Science and Technology and the American Physical Society Topical Group on shock compression of condensed matter. This conference dealt with the full spectrum of both static and dynamic high pressure investigations. Topics discussed include atomic and molecular structure, equations of

S. C. Schmidt; J. W. Shaner; G. A. Samara; M. Ross

1994-01-01

178

Manufacturing Diamond Under Very High Pressure  

NASA Technical Reports Server (NTRS)

A process for manufacturing bulk diamond has been made practical by the invention of the High Pressure and Temperature Apparatus capable of applying the combination of very high temperature and high pressure needed to melt carbon in a sufficiently large volume. The apparatus includes a reaction cell wherein a controlled static pressure as high as 20 GPa and a controlled temperature as high as 5,000 C can be maintained.

Voronov, Oleg

2007-01-01

179

Dynamic Wall Pressure Measurements.  

National Technical Information Service (NTIS)

The state of the art in measurement and interpretation of dynamic wall pressure beneath a turbulent boundary layer is reviewed. The mean pressure increase for shear flow over an orifice in a wall is explained, using triple deck theory, to stem from stream...

P. Leehey

1988-01-01

180

Tritium high pressure target  

NASA Astrophysics Data System (ADS)

The design of a tritium high pressure target with a volume of 16.5 cm3, developed at the RFNC-VNIIEF for research of muon fusion catalyzed in a H-D-T hydrogen isotopic mixture at pressures up to 120 MPa in the range of operating temperatures 300-800 K, is presented.

Perevozchikov, V. V.; Yukhimchuk, A. A.; Demin, D. L.; Ganchuk, N. S.; Grebinnik, V. G.; Grishechkin, S. K.; Ishkov, P. D.; Khabarov, Yu. A.; Lobanov, V. N.; Malkov, I. L.; Tikhonov, V. I.; Zinov, V. G.

1999-06-01

181

Pressure vessel flex joint  

NASA Technical Reports Server (NTRS)

An airtight, flexible joint is disclosed for the interfacing of two pressure vessels such as between the Space Station docking tunnel and the Space Shuttle Orbiter bulkhead adapter. The joint provides for flexibility while still retaining a structural link between the two vessels required due to the loading created by the internal/external pressure differential. The joint design provides for limiting the axial load carried across the joint to a specific value, a function returned in the Orbiter/Station tunnel interface. The flex joint comprises a floating structural segment which is permanently attached to one of the pressure vessels through the use of an inflatable seal. The geometric configuration of the joint causes the tension between the vessels created by the internal gas pressure to compress the inflatable seal. The inflation pressure of the seal is kept at a value above the internal/external pressure differential of the vessels in order to maintain a controlled distance between the floating segment and pressure vessel. The inflatable seal consists of either a hollow torus-shaped flexible bladder or two rolling convoluted diaphragm seals which may be reinforced by a system of straps or fabric anchored to the hard structures. The joint acts as a flexible link to allow both angular motion and lateral displacement while it still contains the internal pressure and holds the axial tension between the vessels.

Kahn, Jon B. (inventor)

1992-01-01

182

Aspirated High Pressure Compressor.  

National Technical Information Service (NTIS)

The design and test of a two-stage, vaneless, aspirated counter- rotating fan is presented in this paper. The fan nominal design objectives were a pressure ratio of 3:1 and adiabatic efficiency of 87%. A pressure ratio of 2.9 at 89% efficiency was measure...

A. A. Merchant A. H. Epstein G. R. Guenette J. L. Kerrebrock R. C. Maclaurin

2006-01-01

183

Pressure-gain combustion  

SciTech Connect

Pulse combustion has been proposed for gas turbine applications in many early articles and more recently has been demonstrated to produce so-called ``pressure-gain`` in a small gas turbine. The basic concept is that the oscillatory combustion occurs as a constant-volume process, producing a gain in the stagnation pressure of air flowing through the combustor, rather than the pressure loss associated with conventional, steady combustion. If properly utilized, this pressure-gain could enhance simple-cycle gas turbine efficiency several percent, depending on the operating conditions. In addition, pulse combustors have demonstrated relatively low NO{sub x} pollutant levels in some applications. The combined potential for higher cycle efficiency and lower pollutant levels is the basis for the present investigation. Tests in progress at the Morgantown Energy Technology Center (METC) have considered a baseline pulse combustor configuration that has shown good oscillating performance, low NO{sub x} emissions, but disappointing results in terms of pressure-gain. However, a combination of numeric simulations and test data suggest that pressure-gain can be produced by a select combination of operating conditions and combustor geometry, but is especially sensitive to the combustor inlet geometry. Tests in progress will evaluate the effect of inlet geometry and operating pressure on both pollutant emissions and pressure-gain.

Richards, G.A.; Yip, J.; Gemmen, R.S.; Janus, M.C.; Norton, T. [USDOE Morgantown Energy Technology Center, WV (United States); Rogers, W.A. [EG and G Washington Analytical Services Center, Inc., Morgantown, WV (United States)

1993-11-01

184

HRT PRESSURIZER HEATER  

Microsoft Academic Search

The electric pressurizer heaters were designed for inherent safety and ; ease of remote maintenance; they clamp around 2-in. pipes leading to the ; pressurizer and have a heating capacity of 7 kw. Two such heaters were tested on ; a length of 347 stainless steel pipe capped on each end to make a bomb with ; provisions inside for

J. A. Hafford; I. Spiewak

1954-01-01

185

Clamp Restrains Pressure Line  

NASA Technical Reports Server (NTRS)

Safety restraint protects people and property if a high-pressure fitting fails. As long as pressure line remains attached at the fitting, clamp exerts essentially no force on hose. If fitting fails, force of fluid leaving free end of hose causes the cam on the clamp to compress hose with a positive locking action.

Aliberti, J. A.

1982-01-01

186

Duct Pressure Actuated Nozzle.  

National Technical Information Service (NTIS)

The patent application relates to a variable area nozzle which uses high pressure duct nozzle air directly to actuate a variable area nozzle and thereby control the nozzle throat area. A servo controlled air valve directs the duct air pressure into a pres...

J. H. Maurer

1976-01-01

187

Hydrostatic Pressure Equilibrated Tensiometer.  

National Technical Information Service (NTIS)

A tensiometer has been developed that can measure long-term wire system performance at any depth, immune to hydrostatic pressure effects. Line tension is sensed and displayed on a Bourdon-type pressure gauge which is photographed at preselected intervals ...

S. Niskin

1975-01-01

188

Summing pressure compensation control  

SciTech Connect

This patent describes a summing pressure compensator control for hydraulic loads with at least one of the hydraulic loads being a variable displacement motor having servo means for controlling the displacement thereof, first hydraulic means responsive to the supply of fluid to the variable displacement motor to provide a first pressure signal, second hydraulic means responsive to the supply of fluid to a second hydraulic load to provide a second pressure signal, summing means for receiving the first and second pressure signals and providing a control signal proportional to the sum of the first and second pressure signals, the control signal being applied to the servo means to increase the displacement of the variable displacement motor.

Myers, H.A.

1988-04-26

189

PRESSURE ACTIVATED SEALANT TECHNOLOGY  

SciTech Connect

The objective of this project is to develop new, efficient, cost effective methods of internally sealing natural gas pipeline leaks through the application of differential pressure activated sealants. In researching the current state of the art for gas pipeline sealing technologies we concluded that if the project was successful, it appeared that pressure activated sealant technology would provide a cost effective alternative to existing pipeline repair technology. From our analysis of current field data for a 13 year period from 1985 to 1997 we were able to identify 205 leaks that were candidates for pressure activated sealant technology, affirming that pressure activated sealant technology is a viable option to traditional external leak repairs. The data collected included types of defects, areas of defects, pipe sizes and materials, incident and operating pressures, ability of pipeline to be pigged and corrosion states. This data, and subsequent analysis, was utilized as a basis for constructing applicable sealant test modeling.

Michael A. Romano

2004-04-01

190

Modeling Scala Media as a Pressure Vessel  

NASA Astrophysics Data System (ADS)

The clinical condition known as endolymphatic hydrops is the swelling of scala media and may result in loss in hearing sensitivity consistent with other forms of low-frequency biasing. Because outer hair cells (OHCs) are displacement-sensitive and hearing levels tend to be preserved despite large changes in blood pressure and CSF pressure, it seems unlikely that the OHC respond passively to changes in static pressures in the chambers. This suggests the operation of a major feedback control loop which jointly regulates homeostasis and hearing sensitivity. Therefore the internal forces affecting the cochlear signal processing amplifier cannot be just motile responses. A complete account of the cochlear amplifier must include static pressures. To this end we have added a third, pressure vessel to our 1-D 140-segment, wave-digital filter active model of cochlear mechanics, incorporating the usual nonlinear forward transduction. In each segment the instantaneous pressure is the sum of acoustic pressure and global static pressure. The object of the model is to maintain stable OHC operating point despite any global rise in pressure in the third chamber. Such accumulated pressure is allowed to dissipate exponentially. In this first 3-chamber implementation we explore the possibility that acoustic pressures are rectified. The behavior of the model is critically dependent upon scaling factors and time-constants, yet by initial assumption, the pressure tends to accumulate in proportion to sound level. We further explore setting of the control parameters so that the accumulated pressure either stays within limits or may rise without bound.

Lepage, Eric; Olofsson, A.?Ke

2011-11-01

191

Pressure relieving support surfaces (PRESSURE) trial: cost effectiveness analysis  

Microsoft Academic Search

Objective To assess the cost effectiveness of alternating pressure mattresses compared with alternating pressure overlays for the prevention of pressure ulcers in patients admitted to hospital. Design Cost effectiveness analysis carried out alongside the pressure relieving support surfaces (PRESSURE) trial; a multicentre UK based pragmatic randomised controlled trial. Setting 11 hospitals in six UK NHS trusts. Participants Intention to treat

Cynthia Iglesias; Jane Nixon; Gillian Cranny; E Andrea Nelson; Kim Hawkins; Angela Phillips; David Torgerson

2006-01-01

192

Vapor Pressure of GD.  

National Technical Information Service (NTIS)

The vapor pressure of pinacolyl methyl phosphonofluoridate O-(I ,2, 2-trimethylpropyl)-methyl phosphonofluoridate. GD has been measured between - 20 and 50 C, using vapor saturation methodology. The current data are in good agreement with data previously ...

A. Balboa D. E. Tevault J. H. Buchanan L. C. Buettner T. Sewell

2007-01-01

193

Resisting Pressures to Smoke.  

National Technical Information Service (NTIS)

Familiarizes students with strategies to resist the pressures to begin cigarette smoking emanating from peers, parental models, and media advertising. Scenes are role-played by junior high school students and adults in natural settings where smoking may o...

1994-01-01

194

High Blood Pressure  

MedlinePLUS

... to high blood pressure: A diet high in salt, fat, and/or cholesterol Chronic conditions such as kidney and hormone problems, diabetes, and high cholesterol Family history: You are more likely to have high blood ...

195

Electrochemical High Pressure Pump.  

National Technical Information Service (NTIS)

The invention provides electrochemically-based methods and devices for producing fluid flow and/or changes in fluid pressure. In the methods and devices of the invention, current is passed through a divided electrochemical cell. Adjacent compartments of t...

C. A. Koval C. E. Evans M. A. Norman R. D. Noble

2005-01-01

196

Hydrazine at high pressure  

NASA Astrophysics Data System (ADS)

We report the first high pressure study of the important rocket fuel, hydrazine in a diamond anvil cell up to 19 GPa. Using Raman spectroscopy, two phase transitions were observed between 5.5 and 8 GPa. Above 8 GPa, a new peak emerged near 3000 cm-1. The pressure-induced changes appear to be reversible as pressure was cycled down to 3.5 GPa. We then performed a second experiment at this pressure examining X-ray induced decomposition of the material using an unfocused synchrotron white beam. After some 2.4 h of irradiation (estimated to be a dose of 1.6 × 105 Gy), molecular nitrogen was produced as confirmed with Raman spectroscopy.

Pravica, Michael; Bai, Ligang; Liu, Yu

2013-01-01

197

High Pressure Synthetic Chemistry.  

ERIC Educational Resources Information Center

Describes several experimental results selected from typical inorganic and organic reaction systems, along with a brief description of the physical parameters needed to determine if a pressure increase will help solve a synthetic problem. (HM)

Hagen, Arnulf P.

1978-01-01

198

Capacitance pressure sensor  

DOEpatents

A microelectromechanical (MEM) capacitance pressure sensor integrated with electronic circuitry on a common substrate and a method for forming such a device are disclosed. The MEM capacitance pressure sensor includes a capacitance pressure sensor formed at least partially in a cavity etched below the surface of a silicon substrate and adjacent circuitry (CMOS, BiCMOS, or bipolar circuitry) formed on the substrate. By forming the capacitance pressure sensor in the cavity, the substrate can be planarized (e.g. by chemical-mechanical polishing) so that a standard set of integrated circuit processing steps can be used to form the electronic circuitry (e.g. using an aluminum or aluminum-alloy interconnect metallization).

Eaton, William P. (Tijeras, NM); Staple, Bevan D. (Albuquerque, NM); Smith, James H. (Albuquerque, NM)

2000-01-01

199

Downhole pressure sensor  

NASA Technical Reports Server (NTRS)

Sensor remains accurate in spite of varying temperatures. Very accurate, sensitive, and stable downhole pressure measurements are needed for vaiety of reservoir engineering applications, such as deep petroleum reservoirs, especially gas reservoirs, and in areas of high geothermal gradient.

Berdahl, C. M.

1980-01-01

200

Pressurized Vessel Slurry Pumping  

SciTech Connect

This report summarizes testing of an alternate ''pressurized vessel slurry pumping'' apparatus. The principle is similar to rural domestic water systems and ''acid eggs'' used in chemical laboratories in that material is extruded by displacement with compressed air.

Pound, C.R.

2001-09-17

201

Internal pressure sensor  

DOEpatents

A pressure sensor for sensing changes in pressure in an enclosed vessel may include a first chamber having at least one expandable section therein that allows that first chamber to change in length. A reference member mounted within the first chamber moves as a result of changes in length of the first chamber. A second chamber having an expandable section therein allows the second chamber to change in length in response to changes in pressure in the enclosed vessel. The second chamber is operatively associated with the first chamber so that changes in length of the second chamber result in changes in length of the first chamber. A sensor operatively associated with the reference member detects changes in position of the reference member. Changes in position of the reference member are related to changes in pressure in the enclosed vessel.

Dowalo, James A. (Blackfoot, ID) [Blackfoot, ID

2010-03-16

202

Analysis of Cyclone Pressure Drop  

Microsoft Academic Search

A new method to analysis cyclone pressure drop is reported. The frictional pressure loss is the primary pressure loss in a cyclone. The air stream travel distance is a function of cyclone diameter. The frictional pressure loss is independent of a cyclone diameter, therefore cyclone total pressure loss is independent of cyclone diameter.

Lingjuan Wang; Calvin B. Parnell; Bryan W. Shaw

203

Radial pressure flange seal  

DOEpatents

This invention provides an all metal seal for vacuum or pressure vessels or systems. This invention does not use gaskets. The invention uses a flange which fits into a matching groove. Fluid pressure is applied in a chamber in the flange causing at least one of the flange walls to radially press against a side of the groove creating the seal between the flange wall and the groove side.

Batzer, T.H.; Call, W.R.

1986-08-12

204

Fullerene microcrystals under pressure  

NASA Astrophysics Data System (ADS)

Solid buckminsterfullerene (C60) is known to be very soft, with a large number of crystalline phases that can be accessed by temperature or pressure. External pressure reduces the intermolecular distance, which affects the electronic structure in three ways: by increasing the overlap between molecular orbitals on neighbor molecules, by inducing additional chemical bonds between molecules, and by deforming the molecular structure. Having an exciton gap that is sensitive to pressure suggests that C60 can be used as active element in an optical pressure gauge: a device that can detect pressure dynamically on the material from the red-shift of its optical spectrum. Using first-principles many-body theories, we calculate the optical gap of solid C60 and its pressure dependence. We also analyze the dependence of optical gap with deformations in the molecule. Our calculations are based on solving the Bethe-Salpeter for electron-hole excitations. The electron self-energy is calculated within the GW approximation. We use pseudopotential density-functional theory to determine the electronic structure of C60 in its ground state.

Tiago, Murilo L.; Reboredo, Fernando A.

2008-03-01

205

Fluctuating shells under pressure.  

PubMed

Thermal fluctuations strongly modify the large length-scale elastic behavior of cross-linked membranes, giving rise to scale-dependent elastic moduli. Whereas thermal effects in flat membranes are well understood, many natural and artificial microstructures are modeled as thin elastic shells. Shells are distinguished from flat membranes by their nonzero curvature, which provides a size-dependent coupling between the in-plane stretching modes and the out-of-plane undulations. In addition, a shell can support a pressure difference between its interior and its exterior. Little is known about the effect of thermal fluctuations on the elastic properties of shells. Here, we study the statistical mechanics of shape fluctuations in a pressurized spherical shell, using perturbation theory and Monte Carlo computer simulations, explicitly including the effects of curvature and an inward pressure. We predict novel properties of fluctuating thin shells under point indentations and pressure-induced deformations. The contribution due to thermal fluctuations increases with increasing ratio of shell radius to thickness and dominates the response when the product of this ratio and the thermal energy becomes large compared with the bending rigidity of the shell. Thermal effects are enhanced when a large uniform inward pressure acts on the shell and diverge as this pressure approaches the classical buckling transition of the shell. Our results are relevant for the elasticity and osmotic collapse of microcapsules. PMID:23150558

Paulose, Jayson; Vliegenthart, Gerard A; Gompper, Gerhard; Nelson, David R

2012-11-27

206

Blood pressure and ageing.  

PubMed

Isolated systolic hypertension, an elevation in systolic but not diastolic pressure, is the most prevalent type of hypertension in those aged 50 or over, occurring either de novo or as a development after a long period of systolic-diastolic hypertension with or without treatment. The increase in blood pressure with age is mostly associated with structural changes in the arteries and especially with large artery stiffness. It is known from various studies that rising blood pressure is associated with increased cardiovascular risk. In the elderly, the most powerful predictor of risk is increased pulse pressure due to decreased diastolic and increased systolic blood pressure. All evidence indicates that treating the elderly hypertensive patient will reduce the risk of cardiovascular events. However, there is no evidence yet for the very elderly. This population is particularly susceptible to side effects of treatments and the reduction of blood pressure, although reducing the risk of cardiovascular events such as stroke, may result in increased mortality. PMID:17308214

Pinto, Elisabete

2007-02-01

207

Fluctuating shells under pressure  

PubMed Central

Thermal fluctuations strongly modify the large length-scale elastic behavior of cross-linked membranes, giving rise to scale-dependent elastic moduli. Whereas thermal effects in flat membranes are well understood, many natural and artificial microstructures are modeled as thin elastic shells. Shells are distinguished from flat membranes by their nonzero curvature, which provides a size-dependent coupling between the in-plane stretching modes and the out-of-plane undulations. In addition, a shell can support a pressure difference between its interior and its exterior. Little is known about the effect of thermal fluctuations on the elastic properties of shells. Here, we study the statistical mechanics of shape fluctuations in a pressurized spherical shell, using perturbation theory and Monte Carlo computer simulations, explicitly including the effects of curvature and an inward pressure. We predict novel properties of fluctuating thin shells under point indentations and pressure-induced deformations. The contribution due to thermal fluctuations increases with increasing ratio of shell radius to thickness and dominates the response when the product of this ratio and the thermal energy becomes large compared with the bending rigidity of the shell. Thermal effects are enhanced when a large uniform inward pressure acts on the shell and diverge as this pressure approaches the classical buckling transition of the shell. Our results are relevant for the elasticity and osmotic collapse of microcapsules.

Paulose, Jayson; Vliegenthart, Gerard A.; Gompper, Gerhard; Nelson, David R.

2012-01-01

208

What Causes High Blood Pressure?  

MedlinePLUS

... page from the NHLBI on Twitter. What Causes High Blood Pressure? Blood pressure tends to rise with ... cold-relief products. Other medicines also can cause high blood pressure (HBP). If you have HBP, let ...

209

Blood pressure monitors for home  

MedlinePLUS

... your arm, a rubber squeeze bulb, and a gauge that measures the blood pressure. A stethoscope is ... blood pressure on the circular dial of the gauge as the needle moves around and the pressure ...

210

Partial-pressure measurement of atmospheric-pressure binary gas using two pressure gauges  

Microsoft Academic Search

We investigated a new method to measure the partial pressure of a binary gas system at near-atmospheric pressure conditions. The method utilizes two types of vacuum gauges, a capacitance manometer and a quartz friction pressure gauge. The partial pressure of the binary gas can be estimated by measuring the impedance change with a quartz friction pressure gauge, which depends on

Akira Kurokawa; Kenji Odaka; Shingo Ichimura

2004-01-01

211

Reotemp Pressure Indicator Local Pressure Indication to Monitor the SCHE Supply Bottle Pressure  

SciTech Connect

These 0-3000 psig range pressure indicators are located in the SCHe helium supply lines at the pressure bottles and upstream of the PRV. These accident monitoring local pressure indicators monitor the SCHe supply bottle pressure. There is one pressure indicator for each SCHe supply (4).

VAN KATWIJK, C.

1999-07-01

212

Cerebrospinal Fluid Pressure and Glaucoma  

PubMed Central

Eyes with normal-pressure glaucoma and those with high-pressure glaucoma can show a similar optic nerve head appearance, while eyes with vascular optic neuropathies show a markedly different optic disc appearance. Factors in addition to intraocular pressure (IOP) may thus play a role in the pathogenesis of glaucomatous optic neuropathy. Clinical and experimental studies showed that (1) physiologic associations between cerebrospinal fluid (CSF) pressure, systemic arterial blood pressure, IOP and body mass index exist; (2) a low CSF pressure was associated with the development of glaucomatous optic nerve damage in cats; (3) patients with normal (intraocular) pressure glaucoma had significantly lower CSF pressure and a higher trans lamina cribrosa pressure difference when compared to normal subjects; and (4) patients with normal- pressure glaucoma as compared with patients with high-pressure glaucoma have a significantly narrower orbital CSF space. A shallow orbital CSF space has been shown to be associated with a low CSF pressure. Due to anatomic reasons, the orbital CSF pressure and the optic nerve tissue pressure (and not the atmospheric pressure) form the retro-laminar counter-pressure against the IOP and are thus part of the trans-lamina cribrosa pressure difference and gradient. Assuming that an elevated trans-lamina cribrosa pressure difference and a steeper trans-lamina cribrosa pressure gradient are important for glaucomatous optic nerve damage, a low orbital CSF pressure would therefore play a role in the pathogenesis of normal-(intraocular) pressure glaucoma. Due to the association between CSF pressure and blood pressure, a low blood pressure could be indirectly involved.

Jonas, Jost B.; Wang, Ningli

2013-01-01

213

Cryogenic High Pressure Sensor Module  

NASA Technical Reports Server (NTRS)

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

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

1999-01-01

214

Cryogenic, Absolute, High Pressure Sensor  

NASA Technical Reports Server (NTRS)

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

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

2001-01-01

215

Automated high pressure cell for pressure jump x-ray diffraction  

SciTech Connect

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

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

2010-06-15

216

Diamondoids under high pressure  

NASA Astrophysics Data System (ADS)

Diamondoid molecules are ultra-stable, saturated hydrocarbons consisting of fused carbon cages superimposing on the diamond lattice, originally found in petroleum. These hydrocarbons, especially higher diamondoids, have been of great interest in recent years due to their potential role in nanotechnology, electronics,and medical technologies. However, the large number of possible intermediates, reaction pathways, and complex reaction kinetics make the synthesis of higher diamondoids extremely difficult. Here we report our efforts in investigating the [121] tetramantane at high pressure by combining x-ray diffraction (XRD) and Raman spectroscopy up to 20 GPa. XRD shows that the [121] tetramantane in a monoclinic structure starts to transform into a high pressure phase at approximately 6 GPa and the transition was almost complete at around 20 GPa. In addition, the high pressure phase displays a large metastability field upon decompression. Raman studies also confirmed this phase transition and the metastability of the high pressure phase based on the peak splitting and pressure shifts, as well as changes in the relative intensity of the most intense peaks. Our study may have implications for developing alternative approaches to synthesize higher diamondoids.

Yang, F.; Lin, Y.; Mao, W. L.

2012-12-01

217

Passive blast pressure sensor  

SciTech Connect

A passive blast pressure sensor for detecting blast overpressures of at least a predetermined minimum threshold pressure. The blast pressure sensor includes a piston-cylinder arrangement with one end of the piston having a detection surface exposed to a blast event monitored medium through one end of the cylinder and the other end of the piston having a striker surface positioned to impact a contact stress sensitive film that is positioned against a strike surface of a rigid body, such as a backing plate. The contact stress sensitive film is of a type which changes color in response to at least a predetermined minimum contact stress which is defined as a product of the predetermined minimum threshold pressure and an amplification factor of the piston. In this manner, a color change in the film arising from impact of the piston accelerated by a blast event provides visual indication that a blast overpressure encountered from the blast event was not less than the predetermined minimum threshold pressure.

King, Michael J.; Sanchez, Roberto J.; Moss, William C.

2013-03-19

218

Flow compensating pressure regulator  

NASA Technical Reports Server (NTRS)

An apparatus for regulating pressure of treatment fluid during ophthalmic procedures is described. Flow sensing and pressure regulating diaphragms are used to modulate a flow control valve. The pressure regulating diaphragm is connected to the flow control valve to urge the valve to an open position due to pressure being applied to the diaphragm by bias means such as a spring. The flow sensing diaphragm is mechanically connected to the flow control valve and urges it to an opened position because of the differential pressure on the diaphragm generated by a flow of incoming treatment fluid through an orifice in the diaphragm. A bypass connection with a variable restriction is connected in parallel relationship to the orifice to provide for adjusting the sensitivity of the flow sensing diaphragm. A multiple lever linkage system is utilized between the center of the second diaphragm and the flow control valve to multiply the force applied to the valve by the other diaphragm and reverse the direction of the force.

Baehr, E. F. (inventor)

1978-01-01

219

Pressure suppression containment system  

DOEpatents

A pressure suppression containment system includes a containment vessel surrounding a reactor pressure vessel and defining a drywell therein containing a non-condensable gas. An enclosed wetwell pool is disposed inside the containment vessel, and a gravity driven cooling system (GDCS) pool is disposed above the wetwell pool in the containment vessel. The wetwell pool includes a plenum for receiving the non-condensable gas carried with steam from the drywell following a loss-of-coolant-accident (LOCA). The wetwell plenum is vented to a plenum above the GDCS pool following the LOCA for suppressing pressure rise within the containment vessel. A method of operation includes channeling steam released into the drywell following the LOCA into the wetwell pool for cooling along with the non-condensable gas carried therewith. The GDCS pool is then drained by gravity, and the wetwell plenum is vented into the GDCS plenum for channeling the non-condensable gas thereto. 6 figures.

Gluntz, D.M.; Townsend, H.E.

1994-03-15

220

Oxygen partial pressure sensor  

DOEpatents

A method for detecting oxygen partial pressure and an oxygen partial pressure sensor are provided. The method for measuring oxygen partial pressure includes contacting oxygen to a solid oxide electrolyte and measuring the subsequent change in electrical conductivity of the solid oxide electrolyte. A solid oxide electrolyte is utilized that contacts both a porous electrode and a nonporous electrode. The electrical conductivity of the solid oxide electrolyte is affected when oxygen from an exhaust stream permeates through the porous electrode to establish an equilibrium of oxygen anions in the electrolyte, thereby displacing electrons throughout the electrolyte to form an electron gradient. By adapting the two electrodes to sense a voltage potential between them, the change in electrolyte conductivity due to oxygen presence can be measured.

Dees, Dennis W. (Downers Grove, IL)

1994-01-01

221

Oxygen partial pressure sensor  

DOEpatents

A method for detecting oxygen partial pressure and an oxygen partial pressure sensor are provided. The method for measuring oxygen partial pressure includes contacting oxygen to a solid oxide electrolyte and measuring the subsequent change in electrical conductivity of the solid oxide electrolyte. A solid oxide electrolyte is utilized that contacts both a porous electrode and a nonporous electrode. The electrical conductivity of the solid oxide electrolyte is affected when oxygen from an exhaust stream permeates through the porous electrode to establish an equilibrium of oxygen anions in the electrolyte, thereby displacing electrons throughout the electrolyte to form an electron gradient. By adapting the two electrodes to sense a voltage potential between them, the change in electrolyte conductivity due to oxygen presence can be measured. 1 fig.

Dees, D.W.

1994-09-06

222

Pressure suppression containment system  

DOEpatents

A pressure suppression containment system includes a containment vessel surrounding a reactor pressure vessel and defining a drywell therein containing a non-condensable gas. An enclosed wetwell pool is disposed inside the containment vessel, and a gravity driven cooling system (GDCS) pool is disposed above the wetwell pool in the containment vessel. The wetwell pool includes a plenum for receiving the non-condensable gas carried with steam from the drywell following a loss-of coolant-accident (LOCA). The wetwell plenum is vented to a plenum above the GDCS pool following the LOCA for suppressing pressure rise within the containment vessel. A method of operation includes channeling steam released into the drywell following the LOCA into the wetwell pool for cooling along with the non-condensable gas carried therewith. The GDCS pool is then drained by gravity, and the wetwell plenum is vented into the GDCS plenum for channeling the non-condensable gas thereto.

Gluntz, Douglas M. (San Jose, CA); Townsend, Harold E. (San Jose, CA)

1994-03-15

223

Intracranial pressure at altitude.  

PubMed

Abstract Wilson, Mark H., Alex Wright, and Christopher H.E. Imray. Intracranial pressure at altitude. High Alt Med Biol. 15:123-132, 2014.- Rapid ascent to high altitude can result in high altitude headache, acute mountain sickness, and less commonly, high altitude cerebral or pulmonary edema. The exact mechanisms by which these clinical syndromes develop remain to be fully elucidated. Direct and indirect measures of intracranial pressure (ICP) usually demonstrate a rise in pressure when human subjects and animals are exposed to acute hypoxia. However, the correlation of ICP changes to symptoms and altitude-related illnesses has been difficult to establish. Headache, for example, may occur with vessel distension prior to a rise in ICP. This article reviews the literature both supporting and refuting an increase in ICP as the underlying mechanism of headaches and other related neurological sequelae experienced at high altitude. PMID:24971766

Wilson, Mark H; Wright, Alex; Imray, Christopher H E

2014-06-01

224

A microwave pressure sounder  

NASA Technical Reports Server (NTRS)

An instrument to measure atmospheric pressure at the earth's surface from an orbiting satellite would be a valuable addition to the expanding inventory of remote sensors. The subject of this report is such an instrument - the Microwave Pressure Sounder (MPS). It is shown that global-ocean coverage is attainable with sufficient accuracy, resolution and observational frequency for meteorological, oceanographic and climate research applications. Surface pressure can be deduced from a measurement of the absorption by an atmospheric column at a frequency in the wing of the oxygen band centered on 60 GHz. An active multifrequency instrument is needed to make this measurement with sufficient accuracy. The selection of optimum operating frequencies is based upon accepted models of surface reflection, oxygen, water vapor and cloud absorption. Numerical simulation using a range of real atmospheres defined by radiosonde observations were used to validate the frequency selection procedure. Analyses are presented of alternative system configurations that define the balance between accuracy and achievable resolution.

Flower, D. A.; Peckham, G. E.

1978-01-01

225

Questions and Answers about High Blood Pressure  

MedlinePLUS

... About High Blood Pressure Questions and Answers About High Blood Pressure What is high blood pressure? Blood pressure is the force of ... by a doctor. Am I at risk for high blood pressure? Anyone can develop high blood pressure. ...

226

Ashcroft Pressure Switch Monitor for Low SCHe Purge Pressure.  

National Technical Information Service (NTIS)

These 0-15 psig pressure switches are located in the SCHe helium purge lines after PCV-5(star)23 and before PCV-5(star)27. The pressure switches monitor the pressure being maintained between the two PCVs and actuate on low pressure of 15 psig. This design...

2002-01-01

227

Variable pressure washer  

NASA Technical Reports Server (NTRS)

A variable pressure washer has two interlocking channel rings separated by a channel and retained by a captive set of fasteners. Within the channel between the rings are multiple rows of springs having at least two different spring moduli. The washer is particularly suited for use with a polar boss assembly secured to a bulkhead of a pressure vessel such as of propellent tank dome structure where the washer allows for the substantially uniform deflection of multiple O-rings as affected by the curved structure.

Smeltzer, III, Stanley S. (Inventor); Estrada, Hector (Inventor)

2004-01-01

228

Casimir light: field pressure.  

PubMed Central

The electromagnetic field is assigned a self-consistent role in which abrupt slowing of the collapse produces radiation and the pressure of the radiation produces abrupt slowing. A simple expression is introduced for the photon spectrum. Conditions for light emission are proposed that imply a high degree of spatial localization. Some numerical checks are satisfied. A study of the mechanical equations of motion suggests an explanation of the very short time scale in terms of oppositely directed field pressures and the speed of light.

Schwinger, J

1994-01-01

229

Slip casting under pressure  

NASA Astrophysics Data System (ADS)

The addition of a pressure during slip casting increases the rate of material deposition and enables larger pieces to be fabricated. In this study, this process has been further developed using monolithic Al2O3 and Al2O3-SiC composites. Slip casting formulations based on both dispersed and coagulated slurries have been analyzed. Excellent results are achieved using coagulated slurries, with no cracking present after drying. The effect of pressure is to increase the green density with a consequent increase in the fired density. In addition, homogeneous microstructures are achieved in the composite system, despite the large difference in particle size used.

Grazzini, H. H.; Wilkinson, D. S.

1992-08-01

230

A novel high pressure tool: the solvation pressure of liquids  

NASA Astrophysics Data System (ADS)

Co-solvents were studied to determine if the change in the cohesive energy density (CED) generates an effective solvation pressure equivalent to the application of an external hydrostatic pressure. Raman modes of chloroform under hydrostatic pressure with co-solvents (chloroform-ethanol, chloroform-acetone) and in the vapour phase were recorded. In some cases the Raman frequency shifts indicate that the solvation pressure behaves as a true hydrostatic pressure. The pressure-induced gelation of starch grains was studied in aqueous media. A higher co-solvent concentration is postulated to put the grains under effective negative pressure, and indeed an increase in the external pressure needed for gelation was seen after the introduction of solvents. The quantitative agreement between the change of solvation pressure and hydrostatic pressure is very good over a wide range of solvent concentration.

Hubel, H.; van Uden, N. W. A.; Faux, D. A.; Dunstan, D. J.

2004-04-01

231

Dynamic Pressure Probes Developed for Supersonic Flow-Field Measurements  

NASA Technical Reports Server (NTRS)

A series of dynamic flow-field pressure probes were developed for use in large-scale supersonic wind tunnels at the NASA Glenn Research Center. These flow-field probes include pitot and static pressure probes that can capture fast-acting flow-field pressure transients occurring on a millisecond timescale. The pitot and static probes can be used to determine local Mach number time histories during a transient event. The flow-field pressure probe contains four major components: 1) Static pressure aerodynamic tip; 2) Pressure-sensing cartridge assembly; 3) Pitot pressure aerodynamic tip; 4) Mounting stem. This modular design allows for a variety of probe tips to be used for a specific application. Here, the focus is on flow-field pressure measurements in supersonic flows, so we developed a cone-cylinder static pressure tip and a pitot pressure tip. Alternatively, probe tips optimized for subsonic and transonic flows could be used with this design. The pressure-sensing cartridge assembly allows the simultaneous measurement of steady-state and transient pressure which allows continuous calibration of the dynamic pressure transducer.

Porro, A. Robert

2001-01-01

232

The first surface micromachined pressure sensor for cardiovascular pressure measurements  

Microsoft Academic Search

A surface micromachined pressure sensor for blood pressure measurements has been commercialized. Using a polysilicon surface micromachining process, a silicon chip with the dimensions of 100×150×1300 ?m and a polysilicon diaphragm area of 103×103 ?m has been fabricated. The piezoresistive pressure sensor has a typical pressure sensitivity of 2.0 ?V\\/V mmHg which results in a blood pressure measurement accuracy better

E. Kalvesten; L. Smith; L. Tenerz; G. Stemme

1998-01-01

233

Saltstone Osmotic Pressure  

SciTech Connect

Recent research into the moisture retention properties of saltstone suggest that osmotic pressure may play a potentially significant role in contaminant transport (Dixon et al., 2009 and Dixon, 2011). The Savannah River Remediation Closure and Disposal Assessments Group requested the Savannah River National Laboratory (SRNL) to conduct a literature search on osmotic potential as it relates to contaminant transport and to develop a conceptual model of saltstone that incorporates osmotic potential. This report presents the findings of the literature review and presents a conceptual model for saltstone that incorporates osmotic potential. The task was requested through Task Technical Request HLW-SSF-TTR-2013-0004. Simulated saltstone typically has very low permeability (Dixon et al. 2008) and pore water that contains a large concentration of dissolved salts (Flach and Smith 2013). Pore water in simulated saltstone has a high salt concentration relative to pore water in concrete and groundwater. This contrast in salt concentration can generate high osmotic pressures if simulated saltstone has the properties of a semipermeable membrane. Estimates of osmotic pressure using results from the analysis of pore water collected from simulated saltstone show that an osmotic pressure up to 2790 psig could be generated within the saltstone. Most semi-permeable materials are non-ideal and have an osmotic efficiency <1 and as a result actual osmotic pressures are less than theoretical pressures. Observations from laboratory tests of simulated saltstone indicate that it may exhibit the behavior of a semi-permeable membrane. After several weeks of back pressure saturation in a flexible wall permeameter (FWP) the membrane containing a simulated saltstone sample appeared to have bubbles underneath it. Upon removal from the FWP the specimen was examined and it was determined that the bubbles were due to liquid that had accumulated between the membrane and the sample. One possible explanation for the accumulation of solution between the membrane and sample is the development of osmotic pressure within the sample. Osmotic pressure will affect fluid flow and contaminant transport and may result in the changes to the internal structure of the semi-permeable material. B?nard et al. 2008 reported swelling of wet cured Portland cement mortars containing salts of NaNO{sub 3}, KNO{sub 3}, Na{sub 3}PO{sub 4}x12H {sub 2}O, and K{sub 3}PO{sub 4} when exposed to a dilute solution. Typically hydraulic head is considered the only driving force for groundwater in groundwater models. If a low permeability material containing a concentrated salt solution is present in the hydrogeologic sequence large osmotic pressures may develop and lead to misinterpretation of groundwater flow and solute transport. The osmotic pressure in the semi-permeable material can significantly impact groundwater flow in the vicinity of the semi-permeable material. One possible outcome is that groundwater will flow into the semi-permeable material resulting in hydrologic containment within the membrane. Additionally, hyperfiltration can occur within semi-permeable materials when water moves through a membrane into the more concentrated solution and dissolved constituents are retained in the lower concentration solution. Groundwater flow and transport equations that incorporate chemical gradients (osmosis) have been developed. These equations are referred to as coupled flow equations. Currently groundwater modeling to assess the performance of saltstone waste forms is conducted using the PORFLOW groundwater flow and transport model. PORFLOW does not include coupled flow from chemico-osmotic gradients and therefore numerical simulation of the effect of coupled flow on contaminant transport in and around saltstone cannot be assessed. Most natural semi-permeable membranes are non-ideal membranes and do not restrict all movement of solutes and as a result theoretical osmotic potential is not realized. Osmotic efficiency is a parameter in the coupled flow equation that accounts for the

Nichols, Ralph L.; Dixon, Kenneth L.

2013-09-23

234

High Blood Pressure and Women  

MedlinePLUS

High Blood Pressure and Women Updated:Feb 5,2014 Many people mistakenly believe that high blood pressure, also called ... content was last reviewed on 02/04/14. High Blood Pressure • Home • About High Blood Pressure (HBP) • Why HBP ...

235

Pressurized Lunar Rover.  

National Technical Information Service (NTIS)

The pressurized lunar rover (PLR) consists of a 7 m long, 3 m diameter cylindrical main vehicle and a trailer which houses the power and heat rejection systems. The main vehicle carries the astronauts, life support systems, navigation and communication sy...

K. Creel J. Frampton D. Honaker K. Mcclure M. Zeinali

1992-01-01

236

A picture of pressure  

NASA Astrophysics Data System (ADS)

A sensor based on an array of piezoelectric ZnO nanowires on a light-emitting GaN substrate can generate high-resolution images of pressure distributions. Zhong Lin Wang tells Nature Photonics that it could lead to superior touch interfaces for electronic devices.

2013-09-01

237

Configuration dependent pressure potentials  

Microsoft Academic Search

Elementary vector methods and the path-independent definition of a conservative force are used to show that a position dependent pressure p on a closed surface is conservative and has the potential ?R dV, where R is the region bounded by the surface.

Dawn Fisher

1988-01-01

238

Pressure-gain combustion.  

National Technical Information Service (NTIS)

Pulse combustion has been proposed for gas turbine applications in many early articles and more recently has been demonstrated to produce so-called ''pressure-gain'' in a small gas turbine. The basic concept is that the oscillatory combustion occurs as a ...

G. A. Richards J. Yip R. S. Gemmen M. C. Janus T. Norton

1993-01-01

239

The Blood Pressure \\  

Microsoft Academic Search

A tremendous amount of scientific evidence regarding the physiology and physiopathology of high blood pressure combined with a sophisticated therapeutic arsenal is at the disposal of the medical community to counteract the overall public health burden of hypertension. Ample evidence has also been gathered from a multitude of large-scale randomized trials indicating the beneficial effects of current treatment strategies in

Cornel Pater

2005-01-01

240

Pressure wall patch  

NASA Technical Reports Server (NTRS)

A rigid patch body for placing over a damaged portion (hole) of an external wall of a pressurized vessel, such as a space vehicle or a habitat, is discussed. The rigid patch body allows an astronaut to make temporary repairs to the pressurized vessel from the exterior of the vessel, which enables more permanent repairs to be made from the interior of the vessel. The pressure wall patch of the present invention includes a floor surrounded by four side members. Each side member includes a threaded screw for anchoring the patch body to the external wall of the pressurized vessel and a recess in its lower surface for supporting an inflatable bladder for surrounding the damaged portion (hole) of the external wall to seal the area surrounding the damaged portion. This allows the vessel to be repressurized. The floor of the rigid patch body supports a source of gas that is connected to the gas supply valve and a gas supply gauge in communication with the gas supply valve and the inflatable bladder.

Williamsen, Joel E. (inventor); Weddendorf, Bruce C. (inventor)

1994-01-01

241

Superconductive Pressure Contacts.  

National Technical Information Service (NTIS)

Superconducting relays with a high critical current (100-200A) capability have been shown to be practical. A study of weakly coupled pressure contacts was also made using an adaptation of the relay. Materials thought most likely to be effective as high cr...

G. K. Gaule J. J. Winter J. T. Breslin

1971-01-01

242

INTERMITTENT POSITIVE PRESSURE BREATHING  

EPA Science Inventory

Efficacy of long-term intermittent positive pressure breathing (IPPB) treatment when used as an adjunct to the overall care of ambulatory outpatients with chronic obstructive pulmonary disease. The evaluation compared the use of IPPB with use of a powered nebulizer....

243

Reactor pressure vessel nozzle  

DOEpatents

A nozzle for joining a pool of water to a nuclear reactor pressure vessel includes a tubular body having a proximal end joinable to the pressure vessel and a distal end joinable in flow communication with the pool. The body includes a flow passage therethrough having in serial flow communication a first port at the distal end, a throat spaced axially from the first port, a conical channel extending axially from the throat, and a second port at the proximal end which is joinable in flow communication with the pressure vessel. The inner diameter of the flow passage decreases from the first port to the throat and then increases along the conical channel to the second port. In this way, the conical channel acts as a diverging channel or diffuser in the forward flow direction from the first port to the second port for recovering pressure due to the flow restriction provided by the throat. In the backflow direction from the second port to the first port, the conical channel is a converging channel and with the abrupt increase in flow area from the throat to the first port collectively increase resistance to flow therethrough.

Challberg, Roy C. (Livermore, CA); Upton, Hubert A. (Morgan Hill, CA)

1994-01-01

244

Reactor pressure vessel nozzle  

DOEpatents

A nozzle for joining a pool of water to a nuclear reactor pressure vessel includes a tubular body having a proximal end joinable to the pressure vessel and a distal end joinable in flow communication with the pool. The body includes a flow passage therethrough having in serial flow communication a first port at the distal end, a throat spaced axially from the first port, a conical channel extending axially from the throat, and a second port at the proximal end which is joinable in flow communication with the pressure vessel. The inner diameter of the flow passage decreases from the first port to the throat and then increases along the conical channel to the second port. In this way, the conical channel acts as a diverging channel or diffuser in the forward flow direction from the first port to the second port for recovering pressure due to the flow restriction provided by the throat. In the backflow direction from the second port to the first port, the conical channel is a converging channel and with the abrupt increase in flow area from the throat to the first port collectively increase resistance to flow therethrough. 2 figs.

Challberg, R.C.; Upton, H.A.

1994-10-04

245

Characteristics of pressure waves  

NASA Technical Reports Server (NTRS)

Air blast characteristics generated by most types of explosions are discussed. Data cover both negative and positive blast load phases and net transverse pressure as a function of time. The effects of partial or total confinement, atmospheric propagation, absorption of energy by ground shock or cratering, and transmission over irregular terrain on blast wave properties were also considered.

1977-01-01

246

Super Pressure (Sverkhdavlenie).  

National Technical Information Service (NTIS)

An experimental press for hydrostatic ultrahigh-pressure extrusion of metals has been designed and built at the VNIIMetmash in cooperation with the Institute of Physics, Academy of Sciences USSR. Numerous problems had to be solved before the design of the...

L. Korolev

1967-01-01

247

High Pressure Plasma Research.  

National Technical Information Service (NTIS)

The research goals, the approach, and the results of the High Pressure Plasma Research, Group V-4, are presented. Also included is a brief description of Air Force applications of this research as well as comprehensive list of publications and presentatio...

U. H. Bauder

1972-01-01

248

Radiolysis and pressurization.  

National Technical Information Service (NTIS)

Radiolysis of water and the concomitant pressurization of the vessels is well recognized in the case of radium needles. The process is the result of the radiolysis of water associated with the radium salts. Mme. Curie, in 1911, anticipated the problems an...

R. H. Sudmann

1988-01-01

249

Radiolysis and pressurization  

Microsoft Academic Search

Radiolysis of water and the concomitant pressurization of the vessels is well recognized in the case of radium needles. The process is the result of the radiolysis of water associated with the radium salts. Mme. Curie, in 1911, anticipated the problems and took pains to eliminate the water of crystallization of the radium chloride to be packed into needles (Morgan,

Sudmann

1988-01-01

250

Arterial Pressure Analog.  

ERIC Educational Resources Information Center

Describes a simple hydraulic analog which allows students to explore some physical aspects of the cardiovascular system and provides them with a means to visualize and conceptualize these basic principles. Simulates the behavior of arterial pressure in response to changes in heart rate, stroke volume, arterial compliance, and peripheral…

Heusner, A. A.; Tracy, M. L.

1980-01-01

251

Extremes of barometric pressure  

Microsoft Academic Search

Ascent to elevated altitude, commonly achieved through flight, by climbing or by residence in highland regions, exposes the individual to reduced ambient pressure. Although there are physical manifestations of this exposure as a consequence of Boyle’s Law, the primary physiological challenge is of hypobaric hypoxia. The acute physiological and longer term adaptive responses of the cardiovascular, respiratory, haematological and neurological

Jane E. Risdall; David P. Gradwell

2008-01-01

252

Extremes of barometric pressure  

Microsoft Academic Search

Ascent to elevated altitude, commonly achieved through flight, by climbing or by residence in highland regions, exposes the individual to reduced ambient pressure. Although there are physical manifestations of this exposure as a consequence of Boyle’s Law, the primary physiological challenge is of hypobaric hypoxia. The acute physiological and longer-term adaptive responses of the cardiovascular, respiratory, haematological and neurological systems

Jane E. Risdall; David P. Gradwell

2011-01-01

253

Topical negative pressure therapy.  

PubMed

Topical negative pressure therapy (TNP) has been available for clinical use in wound management since the late 1990s. It has been shown to be of particular benefit for the treatment of chronic nonhealing wounds and has also recently been positively linked to wound bed preparation. PMID:12640796

Collier, Mark

254

Pressurized lunar rover  

Microsoft Academic Search

The pressurized lunar rover (PLR) consists of a 7 m long, 3 m diameter cylindrical main vehicle and a trailer which houses the power and heat rejection systems. The main vehicle carries the astronauts, life support systems, navigation and communication systems, directional lighting, cameras, and equipment for exploratory experiments. The PLR shell is constructed of a layered carbon-fiber\\/foam composite. The

Kenneth Creel; Jeffrey Frampton; David Honaker; Kerry McClure; Mazyar Zeinali

1992-01-01

255

Pressurized Sonobuoy Deployment System.  

National Technical Information Service (NTIS)

A jet aircraft with integrated, rotary sonobuoy launch system has storage racks for a number of sonobuoys in sonobuoy launch containers; and one or more launcher units in its cabin. Each launcher unit has a pressure shell with a door allowing loading of s...

J. W. Pitzer M. Olsen

2004-01-01

256

Shoes Under Pressure  

NSDL National Science Digital Library

Students explore the basic physics behind walking, and the design and engineering of shoes to accommodate different gaits. They are introduced to pressure, force and impulse as they relate to shoes, walking and running. Students learn about the mechanics of walking, shoe design and common gait misalignments that often lead to injury.

Integrated Teaching And Learning Program

257

Quantum Ferroelectric Pressure Sensor.  

National Technical Information Service (NTIS)

A study was undertaken to find a material that could be used as a temperature-independent, magnetic-field-independent, capacitive pressure sensor for applications below about 10 K. Although the dielectric constant in quantum ferroelectrics is large and in...

W. N. Lawless C. F. Clark

1982-01-01

258

ISCHIECTOMY FOR PRESSURE SORES  

PubMed Central

Ischiectomy with primary closure was carried out in five paraplegic patients with pressure sores. This operation, less extensive than the wide excision with full thickness graft that is now widely advocated, was successful in four of the five cases. In the fifth case none of the several attempts to heal the sores was in the least successful.

Stern, Mark; Cozen, Lewis; Aldes, John

1960-01-01

259

Pressure tester cap  

Microsoft Academic Search

This patent describes a pressure tester cap as of the type having assembly removably mounted on a neck of a radiator of a motor vehicle, a valve assembly of a smaller diameter of the cover assembly urging away from the cover assembly, the improvement comprising; (a) an air valve sleeve having one end supporting the valve assembly and having its

Tubman

1987-01-01

260

Pressure vessel improvement  

US Patent & Trademark Office Database

A multiple shell pressure vessel is fabricated in modular sections comprising a top head module, a nozzle course module and a bottom shell module, each module utilizing telescoping shells with filled interspaces, each shell being removable for inspection and repair with all modular sections and shells being held in compression by a pair of upper and lower single or multilayer tendon skirts held in place by a number of tension members in combination with hydraulic or mechanical jacks or rams. Both tendons and rams are located outside the pressure vessel. Included is a method of arranging the shell flanges and shell radial supports to reduce or eliminate torsional forces on the flanges and flange seals. A leak detection system monitors for leaks in all shells. A method of adjusting shell stresses during operation uses pumps to adjust the pressure of the filler material in the interspaces between shells. The high thermal conductivity of the outer vessel wall, which is due to good thermal bonding provided by the intershell metallic filler-materials, makes it possible to keep the pressure-carrying outer vessel shells cool during service, by cooling the outer shell by plain water, borated water for nuclear reactor vessels, or other coolant.

1992-02-11

261

Pressures to Smoke.  

National Technical Information Service (NTIS)

Shows two junior high school students exploring the problems of smoking and the pressures leading to the habit. The viewer is taken into the lab to witness the effects of smoking on carbon monoxide levels in the body, on nicotine levels in saliva, and on ...

1994-01-01

262

Pressures to Smoke.  

National Technical Information Service (NTIS)

This program shows two junior high school students exploring the problems of smoking and the pressures leading to the habit. The viewer is taken into the lab to witness the effects of smoking on carbon monoxide levels in the body, on nicotine levels in sa...

1994-01-01

263

Sensing line effects on PWR-based differential pressure measurements  

SciTech Connect

An incorrrect configuration of the fluid-filled pressure sensing lines connecting differential pressure transducers to the pressure taps in a pressurized water reactor system can cause errors in the measurement and, during rapid pressure transients, could cause the transducer to fail. Testing was performed in both static and dynamic modes to experimentally determine the effects of sensing lines of various lengths, diameters, and materials. Testing was performed at ambient temperature with absolute line pressures at about 17 MPa using water as the pressure transmission fluid.

Evans, R.P.; Neff, G.G.

1982-02-03

264

Negative Pressure Wound Therapy  

PubMed Central

Executive Summary Objective This review was conducted to assess the effectiveness of negative pressure wound therapy. Clinical Need: Target Population and Condition Many wounds are difficult to heal, despite medical and nursing care. They may result from complications of an underlying disease, like diabetes; or from surgery, constant pressure, trauma, or burns. Chronic wounds are more often found in elderly people and in those with immunologic or chronic diseases. Chronic wounds may lead to impaired quality of life and functioning, to amputation, or even to death. The prevalence of chronic ulcers is difficult to ascertain. It varies by condition and complications due to the condition that caused the ulcer. There are, however, some data on condition-specific prevalence rates; for example, of patients with diabetes, 15% are thought to have foot ulcers at some time during their lives. The approximate community care cost of treating leg ulcers in Canada, without reference to cause, has been estimated at upward of $100 million per year. Surgically created wounds can also become chronic, especially if they become infected. For example, the reported incidence of sternal wound infections after median sternotomy is 1% to 5%. Abdominal surgery also creates large open wounds. Because it is sometimes necessary to leave these wounds open and allow them to heal on their own (secondary intention), some may become infected and be difficult to heal. Yet, little is known about the wound healing process, and this makes treating wounds challenging. Many types of interventions are used to treat wounds. Current best practice for the treatment of ulcers and other chronic wounds includes debridement (the removal of dead or contaminated tissue), which can be surgical, mechanical, or chemical; bacterial balance; and moisture balance. Treating the cause, ensuring good nutrition, and preventing primary infection also help wounds to heal. Saline or wet-to-moist dressings are reported as traditional or conventional therapy in the literature, although they typically are not the first line of treatment in Ontario. Modern moist interactive dressings are foams, calcium alginates, hydrogels, hydrocolloids, and films. Topical antibacterial agents—antiseptics, topical antibiotics, and newer antimicrobial dressings—are used to treat infection. The Technology Being Reviewed Negative pressure wound therapy is not a new concept in wound therapy. It is also called subatmospheric pressure therapy, vacuum sealing, vacuum pack therapy, and sealing aspirative therapy. The aim of the procedure is to use negative pressure to create suction, which drains the wound of exudate (i.e., fluid, cells, and cellular waste that has escaped from blood vessels and seeped into tissue) and influences the shape and growth of the surface tissues in a way that helps healing. During the procedure, a piece of foam is placed over the wound, and a drain tube is placed over the foam. A large piece of transparent tape is placed over the whole area, including the healthy tissue, to secure the foam and drain the wound. The tube is connected to a vacuum source, and fluid is drawn from the wound through the foam into a disposable canister. Thus, the entire wound area is subjected to negative pressure. The device can be programmed to provide varying degrees of pressure either continuously or intermittently. It has an alarm to alert the provider or patient if the pressure seal breaks or the canister is full. Negative pressure wound therapy may be used for patients with chronic and acute wounds; subacute wounds (dehisced incisions); chronic, diabetic wounds or pressure ulcers; meshed grafts (before and after); or flaps. It should not be used for patients with fistulae to organs/body cavities, necrotic tissue that has not been debrided, untreated osteomyelitis, wound malignancy, wounds that require hemostasis, or for patients who are taking anticoagulants. Review Strategy The inclusion criteria were as follows: Randomized controlled trial (RCT) with a sample size of 20 or more Human s

2006-01-01

265

Dual pressure displacement control system  

SciTech Connect

This patent describes a dual pressure servo control system for a variable displacement hydraulic unit having displacement setting means positioned by a hydraulic servo mechanism. The hydraulic unit is provided with main loop lines at least one of which is capable of being subjected to high main loop pressure during operation of the hydraulic unit, a control line including a displacement control valve providing a controlled flow of fluid under pressure to the servo mechanism, and a source of fluid under pressure for the control line comprising a low pressure source connected to the control line through a check valve and high pressure source comprising of a high pressure control line connected to the control line downstream of the check valve. The high pressure control line includes a flow restriction limiting flow to the control line means and generating a significant flow induced pressure drop in the high pressure control line once movement in the servo mechanism is initiated.

Louis, J.E.; Klocke, C.C.

1988-02-02

266

Ambulatory blood pressure in schoolchildren  

PubMed Central

OBJECTIVE—To define the range and variability of ambulatory blood pressure in normal schoolchildren.?DESIGN—Prospective study.?METHODS—Resting blood pressure of 1121 schoolchildren from Newcastle upon Tyne was recorded. An ambulatory blood pressure device, which uses both auscultatory (Korotkoff) and oscillometric methods of blood pressure measurement, was then put in place for 24hours.?RESULTS—The day was divided into three time periods: school, home, and night time. Normal centiles for blood pressure for each of these time periods were obtained and many daytime readings were outside reported normal resting levels. The normal variation of blood pressure was quantified by comparing each of these time periods with the resting readings. Resting systolic blood pressure did not predict 24 hour mean systolic blood pressure.?CONCLUSIONS—The availability of normal ambulatory blood pressure data on the level and variation of blood pressure in children may facilitate the early identification of hypertension in this age group.??

O'Sullivan, J; Derrick, G; Griggs, P; Foxall, R; Aitkin, M; Wren, C

1999-01-01

267

A novel target-type low pressure drop bidirectional optoelectronic air flow sensor for infant artificial ventilation: measurement principle and static calibration.  

PubMed

An optoelectronic target-type volumetric air flow-rate transducer for bidirectional measurements is presented. The sensor is composed of a T-shaped target and two nominally identical LED-photodiode couples which are operated in differential mode. The sensitive surfaces of the photodiodes are differentially shadowed by the deflection of the target, which in turn depends on the gas flow-rate. The principle of operation is described in mathematical terms and the design parameters have been optimized in order to obtain the highest sensitivity along with minimal pressure drop and reduced dimensions. The sensor is placed in a 20 mm diameter hose and was tested with air flow-rate in the typical temperature range of mechanical ventilation between 20 and 40 °C. The theoretical model was validated through experiments carried out in the volumetric flow range from -7.0 to +7.0 l min(-1). The nonlinear behavior allows sensitivities equal to 0.6 V l(-1) min for flow rates ranging from -2.0 to +2.0 l min(-1), equal to 2.0 V l(-1) min for flow rates ranging from -3.0 to -2.0 l min(-1) and from +2.0 to +3.0 l min(-1), up to 5.7 V l(-1) min at higher flow rates ranging from -7.0 to -3.0 l min(-1) and from +3.0 to +7.0 l min(-1). The linear range extends from 3.0 to 7.0 l min(-1) with constant sensitivity equal to 5.7 V l(-1) min. The sensor is able to detect a flow-rate equal to 1.0 l min(-1) with a sensitivity of about 400 mV l(-1) min. The differential nature of the output minimizes the influence of the LEDs' power supply variations and allows to obtain a repeatability in the order of 3% of full scale output. The small pressure drop produced by the sensor placed in-line the fluid stream, of about 2.4 Pa at 7 l min(-1), corresponds to a negligible fluid dynamic resistance lower than 0.34 Pa l(-1) min. PMID:21361616

Saccomandi, Paola; Schena, Emiliano; Silvestri, Sergio

2011-02-01

268

Cellular Pressure-Actuated Joint  

NASA Technical Reports Server (NTRS)

A modification of a pressure-actuated joint has been proposed to improve its pressure actuation in such a manner as to reduce the potential for leakage of the pressurizing fluid. The specific joint for which the modification is proposed is a field joint in a reusable solid-fuel rocket motor (RSRM), in which the pressurizing fluid is a mixture of hot combustion gases. The proposed modification could also be applicable to other pressure-actuated joints of similar configuration.

McGuire, John R.

2003-01-01

269

High-temperature fiber optic pressure sensor  

NASA Technical Reports Server (NTRS)

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

Berthold, J. W.

1984-01-01

270

Middle Ear Pressure: Effects on the Auditory Periphery.  

National Technical Information Service (NTIS)

The effects of direct variation in static middle ear pressure were studied in the acute guinea pig. Pressure differences of from - 500 to + 500 mm of H2O were examined. Pure tones were delivered to the test ear in a closed system and the sound pressure le...

D. L. McPherson J. M. Miller A. Axelsson

1975-01-01

271

Bandstructure, fermi surface and superconductivity of Pr under high pressure  

Microsoft Academic Search

The electronic bandstructures of rare earth metal Praseodymium (Pr) have been calculated for a wide range of static pressures using RAPW method. The density of states and Fermi surface cross sections on the principal planes corresponding to various pressures are obtained. It is seen that, there is, 4f shell breakdown in Pr under pressure and formation of 4f bands. The

M. Dakshinamoorthy; K. Iyakutti; S. Sankar; R. Asokamani

1984-01-01

272

Ultrahigh pressure - Beyond 2 megabars and the ruby fluorescence scale  

Microsoft Academic Search

A new design of the diamond-window, high-pressure cell has permitted static pressure of 2.8 megabars to be generated for the first time. The design is unusually stable mechanically, and thus it should be possible to use the new cell to study most materials, including hydrogen, in the unexplored pressure region above 1 megabar.

P. M. Bell; H. K. Mao; K. Goettel

1984-01-01

273

Does raised intraocular pressure begin in utero?  

PubMed Central

AIM—To determine whether fetal and infant growth, as assessed by weight at birth and weight at 1 year, are related to intraocular pressure.?METHODS—717 men and women born in Hertfordshire between 1920 and 1930, for whom records of birth weight and weight at 1 year were available, were examined. Visual fields were assessed using the Takagi central 25 degree 75 point static threshold screening program. Tonometry was performed using the Perkin's tonometer. The disc was assessed by direct ophthalmoscopy through dilated pupils.?RESULTS—A significant inverse relation was found between systolic blood pressure and birth weight. However, no association was found between birth weight or weight at 1 year and intraocular pressure, cup/disc ratio, or visual field defects.?CONCLUSIONS—There was no evidence to support fetal or infant growth as being important factors for the subsequent development of raised intraocular pressure.?? Keywords: birth weight; intraocular pressure; cup/disc ratio; visual field defects

Foss, A; Rauf, A; Sayer, A; Evans, J; Cooper, C; Wormald, R; Barker, D

1998-01-01

274

Silicon differential pressure transducer line pressure effects and compensation  

NASA Astrophysics Data System (ADS)

A digital compensation method to correct the line pressure induced errors in silicon differential pressure sensors is presented. This method uses dual sensors, namely, one differential pressure sensor and one absolute pressure sensor. The digital compensation technique requires data regarding output deviations of both sensors over varied differential pressure, line pressure, and temperature conditions. The transducer deviations are then corrected with a multivariant polynomial curve which is fit to the data by a microprocessor imbedded in the transducer. Common electronic components are employed in this compensation approach; they include high-accuracy analog-to-digital converters, digital-to-analog converters, microcontrollers, and precision references.

Kim, S. E.; Miller, Mark J.; Guziak, Robert

275

Pressure suppression system  

DOEpatents

A pressure suppression system includes a containment vessel surrounding a reactor pressure vessel and defining a drywell therein containing a non-condensable gas. An enclosed wetwell pool is disposed inside the containment vessel, and an enclosed gravity driven cooling system (GDCS) pool is disposed above the wetwell pool in the containment vessel. The GDCS pool includes a plenum for receiving through an inlet the non-condensable gas carried with steam from the drywell following a loss-of-coolant accident (LOCA). A condenser is disposed in the GDCS plenum for condensing the steam channeled therein and to trap the non-condensable gas therein. A method of operation includes draining the GDCS pool following the LOCA and channeling steam released into the drywell following the LOCA into the GDCS plenum for cooling along with the non-condensable gas carried therewith for trapping the gas therein. 3 figs.

Gluntz, D.M.

1994-10-04

276

Pressure suppression system  

DOEpatents

A pressure suppression system includes a containment vessel surrounding a reactor pressure vessel and defining a drywell therein containing a non-condensable gas. An enclosed wetwell pool is disposed inside the containment vessel, and an enclosed gravity driven cooling system (GDCS) pool is disposed above the wetwell pool in the containment vessel. The GDCS pool includes a plenum for receiving through an inlet the non-condensable gas carried with steam from the drywell following a loss-of-coolant accident (LOCA). A condenser is disposed in the GDCS plenum for condensing the steam channeled therein and to trap the non-condensable gas therein. A method of operation includes draining the GDCS pool following the LOCA and channeling steam released into the drywell following the LOCA into the GDCS plenum for cooling along with the non-condensable gas carried therewith for trapping the gas therein.

Gluntz, Douglas M. (San Jose, CA)

1994-01-01

277

High pressure furnace  

DOEpatents

A high temperature high pressure furnace has a hybrid partially externally heated construction. A metallic vessel fabricated from an alloy having a composition of at least 45% nickel, 15% chrome, and 10% tungsten is utilized (the preferred alloy including 55% nickel, 22% chrome, 14% tungsten, 2% molybdenum, 3% iron (maximum) and 5% cobalt (maximum). The disclosed alloy is fabricated into 11/4 or 2 inch, 32 mm or 50 mm bar stock and has a length of about 22 inches, 56 cm. This bar stock has an aperture formed therein to define a closed high temperature, high pressure oxygen chamber. The opposite and closed end of the vessel is provided with a small blind aperture into which a thermocouple can be inserted. The closed end of the vessel is inserted into an oven, preferably heated by standard nickel chrome electrical elements and having a heavily insulated exterior.

Morris, Donald E. (Kensington, CA)

1993-01-01

278

High pressure furnace  

DOEpatents

A high temperature high pressure furnace has a hybrid partially externally heated construction. A metallic vessel fabricated from an alloy having a composition of at least 45% nickel, 15% chrome, and 10% tungsten is utilized (the preferred alloy including 55% nickel, 22% chrome, 14% tungsten, 2% molybdenum, 3% iron (maximum) and 5% cobalt (maximum)). The disclosed alloy is fabricated into 11/4 or 2 inch, 32 mm or 50 mm bar stock and has a length of about 22 inches, 56 cm. This bar stock has an aperture formed therein to define a closed high temperature, high pressure oxygen chamber. The opposite and closed end of the vessel is provided with a small blind aperture into which a thermocouple can be inserted. The closed end of the vessel is inserted into an oven, preferably heated by standard nickel chrome electrical elements and having a heavily insulated exterior. 19 figures.

Morris, D.E.

1993-09-14

279

High pressure oxygen furnace  

DOEpatents

A high temperature high pressure oxygen furnace having a hybrid partially externally heated construction is disclosed. A metallic bar fabricated from an alloy having a composition of at least 45% nickel, 15% chrome, and 10% tungsten is utilized (the preferred alloy including 55% nickel, 22% chrome, 14% tungsten, 2% molybdenum, 3% iron (maximum) and 5% cobalt (maximum). The disclosed alloy is fabricated into 11/4 inch bar stock and has a length of about 17 inches. This bar stock is gun drilled for over 16 inches of its length with 0.400 inch aperture to define a closed high temperature, high pressure oxygen chamber. The opposite and closed end of the bar is provided with a small support aperture into which both a support and a thermocouple can be inserted. The closed end of the gun drilled bar is inserted into an oven, preferably heated by standard nickel chrome electrical elements and having a heavily insulated exterior.

Morris, Donald E. (Kensington, CA)

1992-01-01

280

High pressure oxygen furnace  

DOEpatents

A high temperature high pressure oxygen furnace having a hybrid partially externally heated construction is disclosed. A metallic bar fabricated from an alloy having a composition of at least 45% nickel, 15% chrome, and 10% tungsten is utilized, the preferred alloy including 55% nickel, 22% chrome, 14% tungsten, 2% molybdenum, 3% iron (maximum) and 5% cobalt (maximum). The disclosed alloy is fabricated into 11/4 inch bar stock and has a length of about 17 inches. This bar stock is gun drilled for over 16 inches of its length with 0.400 inch aperture to define a closed high temperature, high pressure oxygen chamber. The opposite and closed end of the bar is provided with a small support aperture into which both a support and a thermocouple can be inserted. The closed end of the gun drilled bar is inserted into an oven, preferably heated by standard nickel chrome electrical elements and having a heavily insulated exterior. 5 figs.

Morris, D.E.

1992-07-14

281

Pressure activated diaphragm bonder  

DOEpatents

A device is available for bonding one component to another, particularly for bonding electronic components of integrated circuits, such as chips, to a substrate. The bonder device in one embodiment includes a bottom metal block having a machined opening wherein a substrate is located, a template having machined openings which match solder patterns on the substrate, a thin diaphragm placed over the template after the chips have been positioned in the openings therein, and a top metal block positioned over the diaphragm and secured to the bottom block, with the diaphragm retained therebetween. The top block includes a countersink portion which extends over at least the area of the template and an opening through which a high pressure inert gas is supplied to exert uniform pressure distribution over the diaphragm to keep the chips in place during soldering. A heating means is provided to melt the solder patterns on the substrate and thereby solder the chips thereto. 4 figs.

Evans, L.B.; Malba, V.

1997-05-27

282

Configurational constant pressure molecular dynamics.  

PubMed

We propose two new algorithms for generating isothermal-isobaric molecular dynamics. The algorithms are based on an extended phase space dynamics where two extra degrees of freedom, representing the thermostat and the barostat, are included. These new methods adopt a totally different approach towards molecular dynamics simulation in the isothermal-isobaric ensemble. They are fully configurational in the sense that only the particle positions are required in the control of the system temperature and pressure. Following on from the works of Delhommelle and Evans [Mol. Phys., 99, 1825 (2001)] and of Braga and Travis [J. Chem. Phys., 123, 134101 (2005)] concerning configurational canonical dynamics, these new algorithms can be seen as a natural extension to the isothermal-isobaric ensemble. We have validated both of our new configurational isothermal-isobaric schemes by conducting molecular dynamics simulations of a Lennard-Jones fluid and comparing the static and dynamic properties for a single state point. We find that both schemes generate similar results compared with schemes which use kinetic temperature and pressure control. We have also monitored the response of the system to a series of isothermal compressions and isobaric quenches. We find that the configurational schemes performed at least as well as the kinetic based scheme in bringing the system temperature and pressure into line with the set point values of these variables. These new methods will potentially play a significant role in simulations where the calculation of the kinetic temperature and pressure can be problematic. A well known example resides in the field of nonequilibrium simulations where the kinetic temperature and pressure require a knowledge of the streaming velocity of the fluid in order to calculate the true peculiar velocities (or momenta) that enter into their definitions. These are completely avoided by using our configurational thermostats and barostats, since these are independent of momenta. By extending the analysis of Kusnezov et al. [Ann. Phys., 204, 155 (1990)] in order to derive a set of generalized Nose-Hoover equations of motion which can generate isothermal-isobaric dynamics in a number of different ways, we are able to show that both of our new configurational barostats and Hoover's kinetic isothermal-isobaric scheme are special cases of this more general set of equations. This generalization can be very powerful in generating constant pressure dynamics for a variety of systems. PMID:16542063

Braga, Carlos; Travis, Karl P

2006-03-14

283

High pressure induced superconductivity  

Microsoft Academic Search

We have developed complex extreme condition of very low temperature down to 30 mK and ultra high pressure exceeding 200 GPa by assembling compact diamond anvil cell (DAC) on a powerful 3He\\/4He dilution refrigerator. We have also developed measuring techniques of electrical resistance, magnetization and optical measurement for the sample confined in the sample space of the DAC. Using the

K. Amaya; K. Shimizu

2003-01-01

284

Casual Blood Pressure Methodology  

Microsoft Academic Search

\\u000a The concept of measuring blood pressure (BP) has significantly evolved over the past two centuries, overcoming the challenge\\u000a posed by the well-established, but clearly subjective, art of palpation of the pulse for ‘measures’ other than simply determining\\u000a heart rate. In the United States, the BP cuff was introduced by Cushing in Baltimore in 1901 and in Boston in 1903 (1,2)

Lavjay Butani; Bruce Z. Morgenstern

285

Management of intracranial pressure  

Microsoft Academic Search

Although intracranial hypertension may arise from diverse pathology, several basic principles remain paramount to understanding\\u000a its dynamics; however, the management of elevated intracranial pressure (ICP) may be very complex. Initial management of common\\u000a ICP exacerbants is important, such as addressing venous outflow obstruction with upright midline head positioning and treating\\u000a agitation and pain with sedation and analgesia. Surgical decompression of

Thomas J. Wolfe; Michel T. Torbey

2009-01-01

286

Pressure Sensor Process Animation  

NSDL National Science Digital Library

The Southwest Center for Microsystems Education provides information and training on the applications and fabrication of microsystems devices. This animation "gives the viewer an overview of the pressure sensor process used at the MTTC and now at both the NDSCS CNTT - Center for Nanoscience Technology Training in North Dakota and the University of South Florida's Nanotechnology Research Education Center." Each step is shown in detail in this lengthy animation.

2012-10-22

287

High pressure storage vessel  

SciTech Connect

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

Liu, Qiang

2013-08-27

288

Protein crystallization under high pressure.  

PubMed

Pressure is expected to be an important parameter to control protein crystallization, since hydrostatic pressure affects the whole system uniformly and can be changed very rapidly. So far, a lot of studies on protein crystallization have been done. Solubility of protein depends on pressure. For instance, the solubility of tetragonal lysozyme crystal increased with increasing pressure, while that of orthorhombic crystal decreased. The solubility of subtilisin increased with increasing pressure. Crystal growth rates of protein also depend on pressure. The growth rate of glucose isomerase was significantly enhanced with increasing pressure. The growth rate of tetragonal lysozyme crystal and subtilisin decreased with increasing pressure. To study the effects of pressure on the crystallization more precisely and systematically, hen egg white lysozyme is the most suitable protein at this stage, since a lot of data can be used. We focused on growth kinetics under high pressure, since extensive studies on growth kinetics have already been done at atmospheric pressure, and almost all of them have explained the growth mechanisms well. The growth rates of tetragonal lysozyme decreased with pressure under the same supersaturation. This means that the surface growth kinetics significantly depends on pressure. By analyzing the dependence of supersaturation on growth rate, it was found that the increase in average ledge surface energy of the two-dimensional nuclei with pressure explained the decrease in growth rate. At this stage, it is not clear whether the increase in surface energy with increasing pressure is the main reason or not. Fundamental studies on protein crystallization under high pressure will be useful for high pressure crystallography and high pressure protein science. PMID:11983407

Suzuki, Yoshihisa; Sazaki, Gen; Miyashita, Satoru; Sawada, Tsutomu; Tamura, Katsuhiro; Komatsu, Hiroshi

2002-03-25

289

Wideband piezoelectric pressure transducer  

NASA Astrophysics Data System (ADS)

A piezoelectric pressure transducer for pressures of up to 100 MPa was developed, with an operating frequency range from 100 Hz to 1 MHz on the electrical side - sufficiently wide to reproduce pressure profiles of arc discharges with microsecond rise times and millisecond fall times. The sensing element is a disk of TsTS-19 piezoceramic material, 1 mm thick and 5 mm in diameter. It is thermally and electrically insulated from the arc plasma by a compound transmission rod consisting of two quartz crystals 5 mm in diameter and freely sliding inside a teflon sleeve. The 50 mm long waveguide for absorbing acoustic vibrations and thus separating the valid signal from the reflected one consists of brass wires acoustically insulated with epoxy resin and encapsulated into a textolite sleeve with epoxy resin at the other end. A copper housing shields the transducer from electromagnetic interference. The transducer output signal passes through a matching circuit and then a high-impedance voltage divider to a differential amplifier, the latter being shunted by a stabilizing low 1 Mohm resistance at the input. A special feature of this transducer is low-frequency compensation by means of a corrective RC-circuit. After calibration of oscillograms, the transducer has a sensitivity of 1 V/MPa over the 10(-2) to 10 MPa range. Its resolution corresponds to the 2 microsecond maximum rise time of its output signal, with the sensing element located at the end of a shock tube.

Godonyuk, V. A.; Zhuravlev, B. V.; Shedko, I. P.

1986-02-01

290

Hybrid Inflatable Pressure Vessel  

NASA Technical Reports Server (NTRS)

Figure 1 shows a prototype of a large pressure vessel under development for eventual use as a habitable module for long spaceflight (e.g., for transporting humans to Mars). The vessel is a hybrid that comprises an inflatable shell attached to a rigid central structural core. The inflatable shell is, itself, a hybrid that comprises (1) a pressure bladder restrained against expansion by (2) a web of straps made from high-strength polymeric fabrics. On Earth, pressure vessels like this could be used, for example, as portable habitats that could be set up quickly in remote locations, portable hyperbaric chambers for treatment of decompression sickness, or flotation devices for offshore platforms. In addition, some aspects of the design of the fabric straps could be adapted to such other items as lifting straps, parachute straps, and automotive safety belts. Figure 2 depicts selected aspects of the design of a vessel of this type with a toroidal configuration. The bladder serves as an impermeable layer to keep air within the pressure vessel and, for this purpose, is sealed to the central structural core. The web includes longitudinal and circumferential straps. To help maintain the proper shape upon inflation after storage, longitudinal and circumferential straps are indexed together at several of their intersections. Because the web is not required to provide a pressure seal and the bladder is not required to sustain structural loads, the bladder and the web can be optimized for their respective functions. Thus, the bladder can be sealed directly to the rigid core without having to include the web in the seal substructure, and the web can be designed for strength. The ends of the longitudinal straps are attached to the ends of the rigid structural core by means of clevises. Each clevis pin is surrounded by a roller, around which a longitudinal strap is wrapped to form a lap seam with itself. The roller is of a large diameter chosen to reduce bending of the fibers in the strap. The roller also serves to equalize the load in the portions of the strap on both sides of the clevis pin. The lap seam is formed near the clevis by use of a tapered diamond stitch: This stitch is designed specifically to allow fibers in the stitch and strap to relax under load in such a manner that the load becomes more nearly evenly distributed among all fibers in the stitch region. Thus, the tapered diamond stitch prevents load concentrations that could cause premature failure of the strap and thereby increases the strength of the strap/structural-core joint. The lap seam can be rated at >90 percent of the strength of the strap material.

Raboin, Jasen; Valle, Gerard D.; Edeen, Gregg; DeLaFuente, Horacio M.; Schneider, William C.; Spexarth, Gary R.; Johnson, Christopher J.; Pandya, Shalini

2004-01-01

291

Vapour Pressure of Americium(III) Chloride.  

National Technical Information Service (NTIS)

Based on the method described by Fischer, an ultramicro-size apparatus was developed for static determination of the saturation vapour pressure of highly radioactive materials. The apparatus was tested with MgCl sub 2 , MnCl sub 2 , HoCl sub 3 and ScF sub...

W. Schuster

1983-01-01

292

High-Pressure Promoted-Combustion Chamber  

NASA Technical Reports Server (NTRS)

Proposed combustion-testing chamber burns specimens of materials in fully contained, high-pressure oxygen atmosphere. Test operator uses handles on threaded retaining rings to attach or remove top or bottom plates sealing combustion chamber. Tests conducted in static or flowing oxygen. Oxygen inlet and outlet far enough above burning specimen, little danger of entrainment of burning fragments in oxygen flowing out.

Rucker, Michelle A.; Stoltzfus, Joel M.

1990-01-01

293

Pressure-Application Device for Testing Pressure Sensors  

NASA Technical Reports Server (NTRS)

A portable pressure-application device has been designed and built for use in testing and calibrating piezoelectric pressure transducers in the field. The device generates pressure pulses of known amplitude. A pressure pulse (in contradistinction to a steady pressure) is needed because in the presence of a steady pressure, the electrical output of a piezoelectric pressure transducer decays rapidly with time. The device includes a stainless- steel compressed-air-storage cylinder of 500 cu cm volume. A manual hand pump with check valves and a pressure gauge are located at one end of the cylinder. A three-way solenoid valve that controls the release of pressurized air is located at the other end of the cylinder. Power for the device is provided by a 3.7-V cordless-telephone battery. The valve is controlled by means of a pushbutton switch, which activates a 5 V to +/-15 V DC-to-DC converter that powers the solenoid. The outlet of the solenoid valve is connected to the pressure transducer to be tested. Before the solenoid is energized, the transducer to be tested is at atmospheric pressure. When the solenoid is actuated by the push button, pressurized air from inside the cylinder is applied to the transducer. Once the pushbutton is released, the cylinder pressure is removed from the transducer and the pressurized air applied to the transducer is vented, bringing the transducer back to atmospheric pressure. Before this device was used for actual calibration, its accuracy was checked with a NIST (National Institute of Standards and Technology) traceable calibrator and commercially calibrated pressure transducers. This work was done by Wanda Solano of Stennis Space Center and Greg Richardson of Lockheed Martin Corp.

2002-01-01

294

Negative Pressure Tail of a Reflected Pressure Pulse  

Microsoft Academic Search

A numerical pressure wave reflection experiment in a two-dimensional liquid and its comparison with experimental results are presented. The liquid is simulated by the pseudo-potential extension of the lattice-Boltzmann method. In the simulation a pressure pulse is produced by a point source and the resulting pressure wave is reflected back by a wettable rigid wall. Negative pressure tail can be

Attila R. Imre; Gábor Házi; Alexey Besov

2003-01-01

295

A control system for maintaining high stability in gas pressure  

SciTech Connect

A pressure control system has been implemented on an experiment designed to detect the presence of fractional charges in bulk matter. The experiment utilizes a liquid-droplet generation technique requiring high-stability gas-pressure delivery to ensure accurate data collection. The pressure control system consists of a pressurized mercury reservoir containing a low-vapor-pressure, diffusion-pump oil. A commercially available differential pressure transducer, servo-driven valve, and controller sense the pressure fluctuations with respect to a static reference pressure. The system can maintain constant pressure to better than one part in 10,000 at working pressures in the range of 100 to 300 psi. 3 refs., 7 figs.

Wuest, C.R.; Hendricks, C.D.

1987-09-01

296

A hydrostatic pressure approach to cuffless blood pressure monitoring  

Microsoft Academic Search

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

P. Shaltis; A. Reisner; H. Asada

2004-01-01

297

Experimental investigation of shock-cell noise reduction for dual-stream nozzles in simulated flight comprehensive data report. Volume 2: Laser velocimeter data, static pressures and shadowgraph photos  

NASA Technical Reports Server (NTRS)

Parameters which contribute to supersonic jet shock noise were investigated for the purpose of determining means to reduce such noise generation to acceptable levels. Six dual-stream test nozzles with varying flow passage and plug closure designs were evaluated under simulated flight conditions in an anechoic chamber. All nozzles had combined convergent-divergent or convergent flow passages. Mean velocity and turbulence velocity measurements of 25 selected flow conditions were performed employing a laser Doppler velocimeter. Static pressure measurements were made to define the actual convergence-divergence condition. Test point definition, tabulation of aerodynamic test conditions, velocity histograms, and shadowgraph photographs are presented. Flow visualization through shadowgraph photography can contribute to the development of an analytical prediction model for shock noise from coannular plug nozzles.

Yamamoto, K.; Janardan, B. A.; Brausch, J. F.; Hoerst, D. J.; Price, A. O.

1984-01-01

298

Pressure Casting in Investment Molds.  

National Technical Information Service (NTIS)

A study was made of methods for pressure casting nonferrous alloys into investment molds. The experimental methods were compared with standard suction casting practices. The best method studied was the direct pressure diaphragm method. By this method, met...

S. Lipson F. Ripkin

1964-01-01

299

High Blood Pressure and Stroke  

MedlinePLUS Videos and Cool Tools

A service of the U.S. National Library of Medicine National Institutes of Health Home About MedlinePlus Site ... March 13, 2014 Related MedlinePlus Pages Blood Pressure Medicines High Blood Pressure Stroke Transcript A broad review ...

300

Cryogenic Multichannel Silicon Pressure Sensor  

NASA Technical Reports Server (NTRS)

The dark squares are silicon pressure sensors. They are bonded to a pre-drilled substrate which supports the sensors and multiplex chips. The substrate is bonded to a metallic tubing plate which has individual pressure ports.

1991-01-01

301

Pressure relief subsystem design description.  

National Technical Information Service (NTIS)

The primary function of the Pressure Relief Subsystem, a subsystem of the Vessel System, is to provide overpressure protection to the Vessel System. When the overpressure setpoint is reached, pressure is reduced by permitting the flow of primary coolant o...

1986-01-01

302

Flow-compensating pressure regulator  

NASA Technical Reports Server (NTRS)

Pressure regulator developed for use with cataract-surgery instrument controls intraocular pressure during substantial variations in flow rate of infusion fluid. Device may be applicable to variety of eye-surgery instruments.

Baehr, E. F.

1979-01-01

303

Stroke and High Blood Pressure  

MedlinePLUS

Stroke and High Blood Pressure Updated:May 30,2014 Stroke is America's no. 4 killer and a leading cause of severe, long-term disability. Since managing high blood pressure, also called hypertension, is the most important thing ...

304

High Blood Pressure During Pregnancy  

MedlinePLUS

... blood pressure affect pregnancy? When a woman has high blood pressure in pregnancy, it may cause less blood to flow to the placenta . The fetus receives less of the oxygen and nutrients it needs. This can cause the ...

305

High Blood Pressure in Pregnancy  

MedlinePLUS

... of the baby. Controlling your blood pressure during pregnancy and getting regular prenatal care are important for ... your baby. Treatments for high blood pressure in pregnancy may include close monitoring of the baby, lifestyle ...

306

Diabetes and blood pressure (image)  

MedlinePLUS

... blood pressure is. Exercising (such as walking), eating low-salt foods, and losing weight (if you are overweight) ... blood pressure is. Exercising (such as walking), eating low-salt foods, and losing weight (if you are overweight) ...

307

Pressure Effects on Enzyme Functions  

Microsoft Academic Search

Hydrostatic pressure is a well-known method for studying protein dynamics and hydration. Recent developments in molecular biology allow us to obtain and investigate recombinant proteins from deep-sea organisms living in high-pressure environments. The aims of this review are to give a brief introduction of the thermodynamic principles of pressure effects on proteins and to highlight the effects of hydrostatic pressure

Eiji Ohmae; Chiho Murakami; Kunihiko Gekko; Chiaki Kato

2007-01-01

308

Magnetohydrodynamics with Anisotropic Ion Pressure  

NASA Astrophysics Data System (ADS)

To simulate the pressure anisotropy of space plasmas, we extended the global magnetohydrodynamics (MHD) model BATS-R-US based on the study of MHD with anisotropic ion pressure and isotropic electron pressure under both the classical and semirelativistic approximation. We derived the characteristic wave speeds for determining time steps and calculating numerical fluxes. Simulations of the Earth's magnetosphere validated the model's ability to reproduce the pressure anisotropy in the magnetosheath.

Meng, X.; Tóth, G.; Gombosi, T. I.

2012-07-01

309

Mechanical characteristics of filament-wound pressure vessel (burst pressure)  

NASA Technical Reports Server (NTRS)

The finite element method is used to analyze the mechanical characteristics of a pressurized filament-wound (FW) pressure vessel, and to predict its burst pressure. The analysis takes into account the bending moment, the stretch-bend coupling effect, nonlinear stress-strain relations, and finite deflection. The analysis is based on two initial failure criteria for laminae, and two ultimate fracture criteria for laminated structures. The numerical results, obtained by applying the load incremental method to the isotensoid CFRP pressure vessel used in the launching of the Zikiken satellite, are in good agreement with the experimental burst pressure and fracture behaviors.

Iida, H.; Uemura, M.

1987-01-01

310

A temperature and pressure controlled calibration system for pressure sensors  

NASA Technical Reports Server (NTRS)

A data acquisition and experiment control system capable of simulating temperatures from -184 to +220 C and pressures either absolute or differential from 0 to 344.74 kPa is developed to characterize silicon pressure sensor response to temperature and pressure. System software is described that includes sensor data acquisition, algorithms for numerically derived thermal offset and sensitivity correction, and operation of the environmental chamber and pressure standard. This system is shown to be capable of computer interfaced cryogenic testing to within 1 C and 34.47 Pa of single channel or multiplexed arrays of silicon pressure sensors.

Chapman, John J.; Kahng, Seun K.

1989-01-01

311

Pressure suit joint analyzer  

NASA Technical Reports Server (NTRS)

A measurement system for simultaneously measuring torque and angular flexure in a pressure suit joint is described. One end of a joint under test is held rigid. A torque transducer is pivotably supported on the other movable end of a joint. A potentiometer is attached to the transducer by an arm. The wiper shaft of the potentiometer is gripped by a reference arm that rotates the wiper shaft the same angle as the flexure of joint. A signal is generated by the potentiometer which is representative of the joint flexure. A compensation circuit converts the output of the transducer to a signal representative of joint torque.

Vykukal, H. C.; Webbon, B. W. (inventors)

1982-01-01

312

High pressure atomization  

NASA Astrophysics Data System (ADS)

The main objective of these grants has been to study the fundamental processes which lead to the atomization of high pressure jets injected into compressed gases through single hole nozzles. Specific topics include: Dependence of Spray Angle and Other Spray Parameters on Nozzle Design and Operating Conditions; Ultra High Speed Filming of Atomizing Jets; Mechanism of Breakup of Highly Super Heated Liquid Jets; Measurements of the Spray Angle of Atomizing Jets; Mechanism of Atomization of a Liquid Jet; Scaling of Transient Laminar, Turbulent, and Spray Jets; Computations of Drop Sizes in Pulsating Sprays and of Liquid Core Length in Vaporizing Sprays; and Scaling of Impulsively Started Sprays.

Bracco, F. V.

1982-03-01

313

Urodynamic pressure sensor  

NASA Technical Reports Server (NTRS)

A transducer system was developed for measuring the closing pressure profile along the female urethra, which provides up to five sensors within the functional length of the urethra. This new development is an improvement over an earlier measurement method that has a smaller sensor area and was unable to respond to transient events. Three sensors were constructed; one of them was subjected to approximately eight hours of use in a clinical setting during which 576 data points were obtained. The complete instrument system, including the signal conditioning electronics, data acquisition unit, and the computer with its display and printer is described and illustrated.

Moore, Thomas

1991-01-01

314

Conflicting Selection Pressures  

NSDL National Science Digital Library

Explore how populations change over time in a NetLogo model of sheep and grass. Experiment with the initial number of sheep, the sheep birthrate, the amount of energy sheep gain from the grass, and the rate at which the grass re-grows. Remove sheep that have a particular trait (better teeth) from the population, then watch what happens to the sheep teeth trait in the population as a whole. Consider conflicting selection pressures to make predictions about other instances of natural selection.

Consortium, The C.

2012-01-13

315

Pressure Rig for Repetitive Casting.  

National Technical Information Service (NTIS)

The invention relates to a pressure rig for repetitive casting of metals. The pressure rig performs like a piston for feeding molten metal into a mold. Pressure is applied to an expandable rubber diaphragm which expands like a balloon to force the metal i...

P. Vasquez W. R. Hutto A. R. Philips

1987-01-01

316

Oscillometric blood pressure monitor modeling  

Microsoft Academic Search

Oscillometric blood pressure monitors are fairly reliable medical equipments, inexpensive and widely used both in domicile and clinical measurements of blood pressure, however they have not yet been subject of deep investigation. The research reported in this paper presents the development of an analytical model of an oscillometric blood pressure monitor, a task which has not been dealt with and

Eduardo C. Pinheiro

2008-01-01

317

Gas Pressure-Drop Experiment  

ERIC Educational Resources Information Center

Most chemical engineering undergraduate laboratories have fluid mechanics experiments in which pressure drops through pipes are measured over a range of Reynolds numbers. The standard fluid is liquid water, which is essentially incompressible. Since density is constant, pressure drop does not depend on the pressure in the pipe. In addition, flow…

Luyben, William L.; Tuzla, Kemal

2010-01-01

318

Marital correlates of blood pressure.  

PubMed

In 1982, 1,260 white spouse pairs, aged 18 years and over, were interviewed as part of the Connecticut Blood Pressure Survey. The present report is based on a systematic analysis of 1) the personal characteristics and behavior of the spouse, 2) the roles and responsibilities of the material partners, and 3) similarity between spouses on selected variables. Results indicated that a number of these marital variables were associated with either systolic or diastolic blood pressure in husbands and in wives. Some components of the marital situation were associated with lower blood pressure whereas others were associated with higher blood pressure. Effects of marriage on blood pressure were observed both for husband's and wife's blood pressures, although the effects varied by sex. Similarity in spouses' behaviors and characteristics were more frequently associated with blood pressure than the individual effects of these behaviors. Age difference, measured as husband older than wife, was associated with lower blood pressure in husband's but with higher blood pressure in wives. Spouse's educational level and occupational status were not significantly related to blood pressure. Responsibility for common household chores (e.g., cooking) was associated with higher blood pressure in wives but responsibility for the family's health care was associated with lower blood pressure in both spouses. PMID:2705436

Speers, M A; Kasl, S V; Ostfeld, A M

1989-05-01

319

Modeling of high pressure thawing  

Microsoft Academic Search

Modeling of freezing and thawing of foodstuffs has been extensively studied. Our application looks at thawing of foodstuffs under high pressure (HP). The phase change temperature of water to ice decreases with increasing pressure below 220 MPa [1] and then allows to achieve higher thawing rate than at atmospheric pressure. Experimental thawing was realised in a HP vessel with pure

J. M. Chourot; R. Lemaire; G. Cornier; A. Le Bail

1996-01-01

320

Calculating Pressures In Electrochemical Cells  

NASA Technical Reports Server (NTRS)

Initial pressure and void volume strongly affect subsequent dependence of pressure on temperature. Semiempirical method calculates operating conditions in electrochemical storage cells equipped with pressure-relief vents. Used to design cells to discharge safely and completely. Conceived for Li/SOCI2 cells, method applicable to other electrochemical cells.

Lutwack, Ralph; Frank, Harvey A.; Attia, Alan I.

1992-01-01

321

Instrument measures dynamic pressure fluctuations  

NASA Technical Reports Server (NTRS)

Pressure probe instrument, incorporating "infinite line" principle, can be used to remotely measure dynamic pressure fluctuations in hot high-pressure environemnts too severe for sensors. System is designed and can be utilized for measurements in core of operating turbofan engine.

Coats, J. W.; Penko, P. E.; Reshotko, M.

1977-01-01

322

Abnormal pressure in hydrocarbon environments  

USGS Publications Warehouse

Abnormal pressures, pressures above or below hydrostatic pressures, occur on all continents in a wide range of geological conditions. According to a survey of published literature on abnormal pressures, compaction disequilibrium and hydrocarbon generation are the two most commonly cited causes of abnormally high pressure in petroleum provinces. In young (Tertiary) deltaic sequences, compaction disequilibrium is the dominant cause of abnormal pressure. In older (pre-Tertiary) lithified rocks, hydrocarbon generation, aquathermal expansion, and tectonics are most often cited as the causes of abnormal pressure. The association of abnormal pressures with hydrocarbon accumulations is statistically significant. Within abnormally pressured reservoirs, empirical evidence indicates that the bulk of economically recoverable oil and gas occurs in reservoirs with pressure gradients less than 0.75 psi/ft (17.4 kPa/m) and there is very little production potential from reservoirs that exceed 0.85 psi/ft (19.6 kPa/m). Abnormally pressured rocks are also commonly associated with unconventional gas accumulations where the pressuring phase is gas of either a thermal or microbial origin. In underpressured, thermally mature rocks, the affected reservoirs have most often experienced a significant cooling history and probably evolved from an originally overpressured system.

Law, B. E.; Spencer, C. W.

1998-01-01

323

The Myth of Peer Pressure.  

ERIC Educational Resources Information Center

The construct of peer pressure was examined as part of a qualitative study of the determinants of mental health for 41 high-risk adolescents. While the concept of peer pressure enables adults to explain youths' troubling behaviors, content analysis of the participants' accounts of their lives reveals peer pressure to be a myth. (Author/MKA)

Ungar, Michael T.

2000-01-01

324

Hydrostatic pressure mimics gravitational pressure in characean cells  

NASA Technical Reports Server (NTRS)

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

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

1992-01-01

325

Pressure polymerization of polyester  

DOEpatents

A process is disclosed for the preparation of a polyester polymer or polyester copolymer under superatmospheric pressure conditions in a pipe or tubular reaction under turbannular flow conditions. Reaction material having a glycol equivalents to carboxylic acid equivalents mole ratio of from 1.0:1 to 1.2:1, together with a superatmospheric dense gaseous medium are fed co-currently to the reactor. Dicarboxylic acid and/or diol raw materials may be injected into any of the reaction zones in the process during operation to achieve the overall desired mole ratio balance. The process operates at temperatures of from about 220.degree. C. to about 320.degree. C., with turbannular flow achieved before the polymer product and gas exit the reactor process. The pressure in the reaction zones can be in the range from 15 psia to 2500 psia. A polymer product having a DP of a greater than 40, more preferably at least about 70, is achieved by the transfer of water from the reacting material polymer melt to the gaseous medium in the reactor.

Maurer, Charles J. (Matthews, NC); Shaw, Gordon (Charlotte, NC); Smith, Vicky S. (Greer, SC); Buelow, Steven J. (Los Alamos, NM); Tumas, William (Los Alamos, NM); Contreras, Veronica (San Antonio, TX); Martinez, Ronald J. (Santa Cruz, NM)

2000-08-29

326

Ratchetting in pressurized pipes  

NASA Astrophysics Data System (ADS)

The plastic deformation of thin-walled cylinders has been experimentally examined for the loading conditions of +/- 1% axial strain with hoop stresses of approximately 0, 1/4, 1/2 and 3/4 of the initial uniaxial yield stress. Two materials similar to those used in the pipework of PWR nuclear plant in the U.K. have been tested, namely 304S11 stainless steel and En6 low-carbon steel. The results of the tests were to be compared with the allowable stresses and deformations specified in the ASME Boiler and Pressure Vessel Code, Section III. The code specifies that a prescribed combination of primary stresses must not exceed 1.5S(sub m), where S(sub m) is a stress value defined for each material. The results indicate that the limit of 1.5S(sub m) is excessively low for both materials and that in particular, the stainless steel could tolerate 5S(sub m). Although the En6 steel is more prone to ratchetting than the stainless steel, the results suggest that it too could tolerate a higher primary stress than the code allows. Both materials are shown to satisfy the proposed ASME ratchet strain limit of 5% hoop strain after 10 cycles of +/- 1% axial strain range, for any value of internal pressure.

Rider, R. J.; Harvey, S. J.; Charles, I. D.

1994-04-01

327

Management of Chronic Pressure Ulcers  

PubMed Central

Executive Summary In April 2008, the Medical Advisory Secretariat began an evidence-based review of the literature concerning pressure ulcers. Please visit the Medical Advisory Secretariat Web site, http://www.health.gov.on.ca/english/providers/program/mas/tech/tech_mn.html to review these titles that are currently available within the Pressure Ulcers series. Pressure ulcer prevention: an evidence based analysis The cost-effectiveness of prevention strategies for pressure ulcers in long-term care homes in Ontario: projections of the Ontario Pressure Ulcer Model (field evaluation) Management of chronic pressure ulcers: an evidence-based analysis Objective The Medical Advisory Secretariat (MAS) conducted a systematic review on interventions used to treat pressure ulcers in order to answer the following questions: Do currently available interventions for the treatment of pressure ulcers increase the healing rate of pressure ulcers compared with standard care, a placebo, or other similar interventions? Within each category of intervention, which one is most effective in promoting the healing of existing pressure ulcers? Background A pressure ulcer is a localized injury to the skin and/or underlying tissue usually over a bony prominence, as a result of pressure, or pressure in conjunction with shear and/or friction. Many areas of the body, especially the sacrum and the heel, are prone to the development of pressure ulcers. People with impaired mobility (e.g., stroke or spinal cord injury patients) are most vulnerable to pressure ulcers. Other factors that predispose people to pressure ulcer formation are poor nutrition, poor sensation, urinary and fecal incontinence, and poor overall physical and mental health. The prevalence of pressure ulcers in Ontario has been estimated to range from a median of 22.1% in community settings to a median of 29.9% in nonacute care facilities. Pressure ulcers have been shown to increase the risk of mortality among geriatric patients by as much as 400%, to increase the frequency and duration of hospitalization, and to decrease the quality of life of affected patients. The cost of treating pressure ulcers has been estimated at approximately $9,000 (Cdn) per patient per month in the community setting. Considering the high prevalence of pressure ulcers in the Ontario health care system, the total cost of treating pressure ulcers is substantial. Technology Wounds normally heal in 3 phases (inflammatory phase, a proliferative phase of new tissue and matrix formation, and a remodelling phase). However, pressure ulcers often fail to progress past the inflammatory stage. Current practice for treating pressure ulcers includes treating the underlying causes, debridement to remove necrotic tissues and contaminated tissues, dressings to provide a moist wound environment and to manage exudates, devices and frequent turning of patients to provide pressure relief, topical applications of biologic agents, and nutritional support to correct nutritional deficiencies. A variety of adjunctive physical therapies are also in use. Method Health technology assessment databases and medical databases were searched from 1996 (Medline), 1980 (EMBASE), and 1982 (CINAHL) systematically up to March 2008 to identify randomized controlled trials (RCTs) on the following treatments of pressure ulcers: cleansing, debridement, dressings, biological therapies, pressure-relieving devices, physical therapies, nutritional therapies, and multidisciplinary wound care teams. Full literature search strategies are reported in appendix 1. English-language studies in previous systematic reviews and studies published since the last systematic review were included if they had more than 10 subjects, were randomized, and provided objective outcome measures on the healing of pressure ulcers. In the absence of RCTs, studies of the highest level of evidence available were included. Studies on wounds other than pressure ulcers and on surgical treatment of pressure ulcers were excluded. A total of 18 systematic reviews, 104 RCTs, and 4 observational

2009-01-01

328

Correlation and spectral measurements of fluctuating pressures and velocities in annular turbulent flow. [PWR; BWR  

SciTech Connect

An experimental study of the fluctuating velocity field, the fluctuating static wall pressure and the in-stream fluctuating static pressure in an annular turbulent air flow system with a radius ratio of 4.314 has been conducted. The study included direct measurements of the mean velocity profile, turbulent velocity field; fluctuating static wall pressure and in-stream fluctuating static pressure from which the statistical values of the turbulent intensity levels, power spectral densities of the turbulent quantities, the cross-correlation between the fluctuating static wall pressure and the fluctuating static pressure in the core region of the flow and the cross-correlation between the fluctuating static wall pressure and the fluctuating velocity field in the core region of the flow were obtained.

Wilson, R.J.; Jones, B.G.; Roy, R.P.

1980-02-01

329

High-pressure neutron diffraction  

SciTech Connect

This lecture will cover progress and prospect of applications of high-pressure neutron diffraction techniques to Earth and materials sciences. I will first introduce general high-pressure research topics and available in-situ high-pressure techniques. Then I'll talk about high-pressure neutron diffraction techniques using two types of pressure cells: fluid-driven and anvil-type cells. Lastly, I will give several case studies using these techniques, particularly, those on hydrogen-bearing materials and magnetic transitions.

Xu, Hongwu [Los Alamos National Laboratory

2011-01-10

330

Reproducibility of twitch mouth pressure, sniff nasal inspiratory pressure, and maximal inspiratory pressure  

Microsoft Academic Search

Twitch mouth pressure (Pmo,tw) during magnetic phrenic nerve stimula- tion and sniff nasal inspiratory pressure (SNIP) were recently proposed as alternative noninvasive methods for assessing inspiratory muscle strength. This study aimed to compare their reproducibility with maximal inspiratory pressure (MIP) in normal subjects. Ten healthy subjects were studied at functional residual capacity in semirecumbent position. Cervical magnetic phrenic nerve stimulation

J. O. Maillard; L. Burdet; G. van Melle; J. W. Fitting

1998-01-01

331

Assessment of fiber optic pressure sensors  

SciTech Connect

This report presents the results of a six-month Phase 1 study to establish the state-of-the-art in fiber optic pressure sensing and describes the design and principle of operation of various fiber optic pressure sensors. This study involved a literature review, contact with experts in the field, an industrial survey, a site visit to a fiber optic sensor manufacturer, and laboratory testing of a fiber optic pressure sensor. The laboratory work involved both static and dynamic performance tests. In addition, current requirements for environmental and seismic qualification of sensors for nuclear power plants were reviewed to determine the extent of the qualification tests that fiber optic pressure sensors may have to meet before they can be used in nuclear power plants. This project has concluded that fiber optic pressure sensors are still in the research and development stage and only a few manufacturers exist in the US and abroad which supply suitable fiber optic pressure sensors for industrial applications. Presently, fiber optic pressure sensors are mostly used in special applications for which conventional sensors are not able to meet the requirements.

Hashemian, H.M.; Black, C.L.; Farmer, J.P. [Analysis and Measurement Services Corp., Knoxville, TN (United States)

1995-04-01

332

A constant pressure bomb  

NASA Technical Reports Server (NTRS)

This report describes a new optical method of unusual simplicity and of good accuracy suitable to study the kinetics of gaseous reactions. The device is the complement of the spherical bomb of constant volume, and extends the applicability of the relationship, pv=rt for gaseous equilibrium conditions, to the use of both factors p and v. The method substitutes for the mechanical complications of a manometer placed at some distance from the seat of reaction the possibility of allowing the radiant effects of reaction to record themselves directly upon a sensitive film. It is possible the device may be of use in the study of the photoelectric effects of radiation. The method makes possible a greater precision in the measurement of normal flame velocities than was previously possible. An approximate analysis shows that the increase of pressure and density ahead of the flame is negligible until the velocity of the flame approaches that of sound.

Stevens, F W

1924-01-01

333

High pressure mechanical seal  

NASA Technical Reports Server (NTRS)

A relatively impervious mechanical seal is formed between the outer surface of a tube and the inside surface of a mechanical fitting of a high pressure fluid or hydraulic system by applying a very thin soft metal layer onto the outer surface of the hard metal tube and/or inner surface of the hard metal fitting. The thickness of such thin metal layer is independent of the size of the tube and/or fittings. Many metals and alloys of those metals exhibit the requisite softness, including silver, gold, tin, platinum, indium, rhodium and cadmium. Suitably, the coating is about 0.0025 millimeters (0.10 mils) in thickness. After compression, the tube and fitting combination exhibits very low leak rates on the order or 10.sup.-8 cubic centimeters per second or less as measured using the Helium leak test.

Babel, Henry W. (Inventor); Anderson, Raymond H. (Inventor)

1996-01-01

334

High pressure mechanical seal  

NASA Technical Reports Server (NTRS)

A relatively impervious mechanical seal is formed between the outer surface of a tube and the inside surface of a mechanical fitting of a high pressure fluid or hydraulic system by applying a very thin soft metal layer onto the outer surface of the hard metal tube and/or inner surface of the hard metal fitting, prior to swaging the fitting onto the tube. The thickness of such thin metal layer is independent of the size of the tube and/or fittings. Many metals and alloys of those metals exhibit the requisite softness, including silver, gold, nickel, tin, platinum, indium, rhodium and cadmium. Suitably, the coating is about 0.0025 millimeters (0.10 mils) in thickness. After swaging, the tube and fitting combination exhibits very low leak rates on the order or 10.sup.-8 cubic centimeters per second or less as meaured using the Helium leak test.

Babel, Henry W. (Inventor); Fuson, Phillip L. (Inventor); Chickles, Colin D. (Inventor); Jones, Cherie A. (Inventor); Anderson, Raymond H. (Inventor)

1995-01-01

335

Pressure vessel bottle mount  

NASA Technical Reports Server (NTRS)

A mounting assembly for mounting a composite pressure vessel to a vehicle includes a saddle having a curved surface extending between two pillars for receiving the vessel. The saddle also has flanged portions which can be bolted to the vehicle. Each of the pillars has hole in which is mounted the shaft portion of an attachment member. A resilient member is disposed between each of the shaft portions and the holes and loaded by a tightening nut. External to the holes, each of the attachment members has a head portion to which a steel band is attached. The steel band circumscribes the vessel and translates the load on the springs into a clamping force on the vessel. As the vessel expands and contracts, the resilient members expand and contract so that the clamping force applied by the band to the vessel remains constant.

Wingett, Paul (Inventor)

2001-01-01

336

Effects of pressure waves  

NASA Technical Reports Server (NTRS)

Two parameters, side on overpressure and side on impulse loads, and their application to the determination of structural damage to buildings and vehicles in the vicinity of an explosion are investigated. Special consideration was given to what constitutes damage and what level of damage is acceptable. Solutions were sorted through the examination of glass breakage, curve fit to bomb damage, overturning of marginal structures (buses, trucks, mobile homes) subject to toppling, and initiation of yielding in either beam or plate structural components. Three different empirical pressure versus impulse diagrams were presented - the first is for minor structural damage involving wrenched joints and partitions, the second is for major damage structural damage with load bearing members at least partially destroyed, and the third is for 50% to 75% of the building demolished. General guidelines were obtained from the results when the accurate structural details are unknown.

1977-01-01

337

Pressure Measurement Sensor  

NASA Technical Reports Server (NTRS)

FFPI Industries Inc. is the manufacturer of fiber-optic sensors that furnish accurate pressure measurements in internal combustion chambers. Such an assessment can help reduce pollution emitted by these engines. A chief component in the sensor owes its seven year- long development to Lewis Research Center funding to embed optical fibers and sensors in metal parts. NASA support to Texas A&M University played a critical role in developing this fiber optic technology and led to the formation of FFPI Industries and the production of fiber sensor products. The simple, rugged design of the sensor offers the potential for mass production at low cost. Widespread application of the new technology is forseen, from natural gas transmission, oil refining and electrical power generation to rail transport and the petrochemical paper product industry.

1997-01-01

338

Planet Under Pressure  

NSDL National Science Digital Library

Planet Under Pressure is a six-part British Broadcasting Company (BBC) News Online series looking at some of the most pressing environmental issues facing the human race today. The series takes a detailed look at six areas where most experts agree that a crisis is brewing. They include food, water, energy, climate change, biodiversity, and pollution. In addition there are special features including: an animated guide that shows how the greenhouse effect might shape our climate; before and after images of the effects of climate change; the European Union (EU) emissions trading scheme and the carbon revolution; opinions about the Kyoto Protocol; graphic climate evidence of a warming world, rising sea, and melting ice; teenagers' opinions on how they would tackle environmental damage; the results of an eco-friendly garden competition; pictures of environmental change around the world; and a link to a BBC website exploring the UN's goals for the planet in 2015.

339

Metastable Water Under Pressure  

NASA Astrophysics Data System (ADS)

We have summarized some of the recent results, including studies for bulk, confined and interfacial water. By analyzing a cell model within a mean field approximation and with Monte Carlo simulations, we have showed that all the scenarios proposed for water's P-T phase diagram may be viewed as special cases of a more general scheme. In particular, our study shows that it is the relationship between H bond strength and H bond cooperativity that governs which scenario is valid. The investigation of the properties of metastable liquid water under pressure could provide essential information that could allow us to understand the mechanisms ruling the anomalous behavior of water. This understanding could, ultimately, lead us to the explanation of the reasons why water is such an essential liquid for life.

Stokely, Kevin; Mazza, Marco G.; Stanley, H. Eugene; Franzese, Giancarlo

340

CubicPressure, a program to calculate pressure with uncertainty  

NASA Astrophysics Data System (ADS)

A program named CubicPressure has been created and posted on-line at http://netfiles.uiuc.edu/liligao2/CubicPressure/. Its main function is to calculate pressure and its uncertainty at high temperature from the lattice parameters of pressure calibrants with cubic structure. The program includes a number of well-established equations of state (EOS) of MgO, Au, Pt, and NaCl. Users are also allowed to input new EOS in the forms of the 3rd-order Birch-Murnaghan EOS at room temperature and Debye thermal EOS at high temperature. Compared with existing programs, CubicPressure is unique in that it allows the calculation of the uncertainty in pressure, which originates not only from the uncertainties in lattice parameters and temperature, but also from the uncertainties in EOS parameters.

Gao, L.; Li, J.

2006-12-01

341

High-pressure cryogenic seals for pressure vessels  

NASA Technical Reports Server (NTRS)

This investigation of the problems associated with reliably containing gaseous helium pressurized to 1530 bars (22 500 psi) between 4.2 K and 150 K led to the following conclusions: (1) common seal designs used in existing elevated-temperature pressure vessels are unsuitable for high-pressure cryogenic operation, (2) extrusion seal-ring materials such as Teflon, tin, and lead are not good seal materials for cryogenic high-pressure operation; and (3) several high-pressure cryogenic seal systems suitable for large-pressure vessel applications were developed; two seals required prepressurization, and one seal functioned repeatedly without any prepressurization. These designs used indium seal rings, brass or 304 stainless-steel anvil rings, and two O-rings of silicone rubber or Kel-F.

Buggele, A. E.

1977-01-01

342

Thermodynamic equilibrium at heterogeneous pressure  

NASA Astrophysics Data System (ADS)

Recent advances in metamorphic petrology point out the importance of grain-scale pressure variations in high-temperature metamorphic rocks. Pressures derived from chemical zonation using unconventional geobarometry based on equal chemical potentials fit mechanically feasible pressure variations. Here a thermodynamic equilibrium method is presented that predicts chemical zoning as a result of pressure variations by Gibbs energy minimization. Equilibrium thermodynamic prediction of the chemical zoning in the case of pressure heterogeneity is done by constraint Gibbs minimization using linear programming techniques. Compositions of phases considered in the calculation are discretized into 'pseudo-compounds' spanning the entire compositional space. Gibbs energies of these discrete compounds are generated for a given range and resolution of pressures for example derived by barometry or from mechanical model predictions. Gibbs energy minimization is subsequently performed considering all compounds of different composition and pressure. In addition to constraining the system composition a certain proportion of the system is constraint at a specified pressure. Input pressure variations need to be discretized and each discrete pressure defines an additional constraint for the minimization. The proportion of the system at each different pressure is equally distributed over the number of input pressures. For example if two input pressures P1 and P2 are specified, two constraints are added: 50 percent of the system is constraint at P1 while the remaining 50 percent is constraint at P2. The method has been tested for a set of 10 input pressures obtained by Taj?manová et al. (2014) using their unconventional geobarometry method in a plagioclase rim around kyanite. Each input pressure is added as constraint to the minimization (1/10 percent of the system for each discrete pressure). Constraining the system composition to the average composition of the plagioclase rim successfully predicts the observed chemical zoning. In conclusion, Gibbs minimization provides identical results to the geobarometry approach based on chemical potentials thus validating the inferred pressure gradient. The thermodynamic consistency of the calculation is supported by the similar result obtained from two different approaches. Reference: Taj?manová, L., Podladchikov, Y., Powell, R., Moulas, E., Vrijmoed, J. C. & Connolly, J. A. D. (2014). Grain scale pressure variations and chemical equilibrium in high-grade metamorphic rocks. Journal of Metamorphic Geology, (in press).

Vrijmoed, Johannes C.; Podladchikov, Yuri Y.

2014-05-01

343

Solvation pressure as real pressure: I. Ethanol and starch under negative pressure  

NASA Astrophysics Data System (ADS)

The reality of the solvation pressure generated by the cohesive energy density of liquids is demonstrated by three methods. Firstly, the Raman spectrum of ethanol as a function of cohesive energy density (solvation pressure) in ethanol-water and ethanol-chloroform mixtures is compared with the Raman spectrum of pure ethanol under external hydrostatic pressure and the solvation pressure and hydrostatic pressure are found to be equivalent for some transitions. Secondly, the bond lengths of ethanol are calculated by molecular dynamics modelling for liquid ethanol under pressure and for ethanol vapour. The difference in bond lengths between vapour and liquid are found to be equivalent to the solvation pressure for the C-H3, C-H2 and O-H bond lengths, with discrepancies for the C-C and C-O bond lengths. Thirdly, the pressure-induced gelation of potato starch is measured in pure water and in mixtures of water and ethanol. The phase transition pressure varies in accordance with the change in solvation pressure of the solvent. These results demonstrate the reality of 'negative pressures' generated by reductions in the cohesive energy density of solvent mixtures.

van Uden, N. W. A.; Hubel, H.; Faux, D. A.; Tanczos, A. C.; Howlin, B.; Dunstan, D. J.

2003-03-01

344

Pressure solution creep under cyclic loading  

NASA Astrophysics Data System (ADS)

Pressure solution creep was studied on sodium chloride, calcium carbonate and ammonium nitrate in respective saturated aqueous solutions under static loading and cyclic unloading. Ball indentation and powder compaction curves show that each transition from static to cyclic regime produces an increase—sometimes manifold—in creep rate which lasts over the whole time of cyclic impact. After returning to static regime, the initial creep rate reappears. Over longer-term tests, both in static and cyclic regime, the creep gradually slows down. Increasing impact frequency enhances the effect. Any noticeable changes in strain rate are absent in a pure inert medium (paraffin oil). Possible mechanisms of the cyclic unloading effect are discussed.

Traskine, Vladimir; Skvortsova, Zoya; Muralev, Alexey; Zubov, Dmitry

2009-12-01

345

Pressure drop in cyclone separator at high pressure  

Microsoft Academic Search

For the design of pressurized circulating fluidized beds, experiments were conducted in a small cyclone with 120 mm in diameter\\u000a and 300 mm in height at high pressures and at atmospheric temperatures. Influence of air leakage from the stand pipe into\\u000a the cyclone was specially focused. A semi-empirical model was developed for the prediction of the pressure drop of the

Zhiping Zhu; Yongjie Na; Qinggang Lu

2008-01-01

346

Sustainability of superhydrophobicity under pressure  

NASA Astrophysics Data System (ADS)

Prior studies have demonstrated that superhydrophobicity of submerged surfaces is influenced by hydrostatic pressure and other environmental effects. Sustainability of a superhydrophobic surface could be characterized by both how long it maintains the trapped air in its surface pores, so-called ``longevity,'' and the pressure beyond which it undergoes a global wetting transition, so-called ``terminal pressure.'' In this work, we investigate the effects of pressure on the performance of electrospun polystyrene fibrous coatings. The time-dependent hydrophobicity of the submerged coating in a pressure vessel is optically measured under elevated pressures. Rheological studies are also performed to determine the effects of pressure on drag reduction and slip length. The measurements indicate that surface longevity exponentially decays with increasing pressure in perfect agreement with the studies reported in the literature at lower pressures. It is found, however, that fibrous coatings could resist hydrostatic pressures significantly higher than those of previously reported surfaces. Our observations indicate that superhydrophobic fibrous coatings could potentially be used for underwater applications.

Samaha, Mohamed A.; Vahedi Tafreshi, Hooman; Gad-el-Hak, Mohamed

2012-11-01

347

Pressure Inactivation of Bacillus Endospores  

PubMed Central

The inactivation of bacterial endospores by hydrostatic pressure requires the combined application of heat and pressure. We have determined the resistance of spores of 14 food isolates and 5 laboratory strains of Bacillus subtilis, B. amyloliquefaciens, and B. licheniformis to treatments with pressure and temperature (200 to 800 MPa and 60 to 80°C) in mashed carrots. A large variation in the pressure resistance of spores was observed, and their reduction by treatments with 800 MPa and 70°C for 4 min ranged from more than 6 log units to no reduction. The sporulation conditions further influenced their pressure resistance. The loss of dipicolinic acid (DPA) from spores that varied in their pressure resistance was determined, and spore sublethal injury was assessed by determination of the detection times for individual spores. Treatment of spores with pressure and temperature resulted in DPA-free, phase-bright spores. These spores were sensitive to moderate heat and exhibited strongly increased detection times as judged by the time required for single spores to grow to visible turbidity of the growth medium. The role of DPA in heat and pressure resistance was further substantiated by the use of the DPA-deficient mutant strain B. subtilis CIP 76.26. Taken together, these results indicate that inactivation of spores by combined pressure and temperature processing is achieved by a two-stage mechanism that does not involve germination. At a pressure between 600 and 800 MPa and a temperature greater than 60°C, DPA is released predominantly by a physicochemical rather than a physiological process, and the DPA-free spores are inactivated by moderate heat independent of the pressure level. Relevant target organisms for pressure and temperature treatment of foods are proposed, namely, strains of B. amyloliquefaciens, which form highly pressure-resistant spores.

Margosch, Dirk; Ganzle, Michael G.; Ehrmann, Matthias A.; Vogel, Rudi F.

2004-01-01

348

THE VAPOR PRESSURES OF LIQUID Bi-BiClâ SOLUTIONS  

Microsoft Academic Search

The vapor pressures of pure BiClâ and of Bi--BiClâ mixtures ; were redetermined wtth the quasi-static and spiral gage methods and compared with ; data by the transpiration method. The agreement ts within experi;

F. J. Jr. Keneshea; W. Wilson; D. Cubicciotti

1960-01-01

349

Multilayer Composite Pressure Vessels  

NASA Technical Reports Server (NTRS)

A method has been devised to enable the fabrication of lightweight pressure vessels from multilayer composite materials. This method is related to, but not the same as, the method described in gMaking a Metal- Lined Composite-Overwrapped Pressure Vessel h (MFS-31814), NASA Tech Briefs, Vol. 29, No. 3 (March 2005), page 59. The method is flexible in that it poses no major impediment to changes in tank design and is applicable to a wide range of tank sizes. The figure depicts a finished tank fabricated by this method, showing layers added at various stages of the fabrication process. In the first step of the process, a mandrel that defines the size and shape of the interior of the tank is machined from a polyurethane foam or other suitable lightweight tooling material. The mandrel is outfitted with metallic end fittings on a shaft. Each end fitting includes an outer flange that has a small step to accommodate a thin layer of graphite/epoxy or other suitable composite material. The outer surface of the mandrel (but not the fittings) is covered with a suitable release material. The composite material is filament- wound so as to cover the entire surface of the mandrel from the step on one end fitting to the step on the other end fitting. The composite material is then cured in place. The entire workpiece is cut in half in a plane perpendicular to the axis of symmetry at its mid-length point, yielding two composite-material half shells, each containing half of the foam mandrel. The halves of the mandrel are removed from within the composite shells, then the shells are reassembled and bonded together with a belly band of cured composite material. The resulting composite shell becomes a mandrel for the subsequent steps of the fabrication process and remains inside the final tank. The outer surface of the composite shell is covered with a layer of material designed to be impermeable by the pressurized fluid to be contained in the tank. A second step on the outer flange of each end fitting accommodates this layer. Depending on the application, this layer could be, for example, a layer of rubber, a polymer film, or an electrodeposited layer of metal. If the fluid to be contained in the tank is a gas, then the best permeation barrier is electrodeposited metal (typically copper or nickel), which can be effective at a thickness of as little as 0.005 in (.0.13 mm). The electrodeposited metal becomes molecularly bonded to the second step on each metallic end fitting. The permeation-barrier layer is covered with many layers of filament-wound composite material, which could be the same as, or different from, the composite material of the inner shell. Finally, the filament-wound composite material is cured in an ov

DeLay, Tom

2005-01-01

350

Steam Oxidation at High Pressure  

SciTech Connect

A first high pressure test was completed: 293 hr at 267 bar and 670{degrees}C; A parallel 1 bar test was done for comparison; Mass gains were higher for all alloys at 267 bar than at 1 bar; Longer term exposures, over a range of temperatures and pressures, are planned to provide information as to the commercial implications of pressure effects; The planned tests are at a higher combination of temperatures and pressures than in the existing literature. A comparison was made with longer-term literature data: The short term exposures are largely consistent with the longer-term corrosion literature; Ferritic steels--no consistent pressure effect; Austenitic steels--fine grain alloys less able to maintain protective chromia scale as pressure increases; Ni-base alloys--more mass gains above 105 bar than below. Not based on many data points.

Holcomb, Gordon R. [NETL; Carney, Casey [URS

2013-07-19

351

Ocular perfusion pressure in glaucoma.  

PubMed

This review article discusses the relationship between ocular perfusion pressure and glaucoma, including its definition, factors that influence its calculation and epidemiological studies investigating the influence of ocular perfusion pressure on the prevalence, incidence and progression of glaucoma. We also list the possible mechanisms behind this association, and discuss whether it is secondary to changes in intraocular pressure, blood pressure or both. Finally, we describe the circadian variation of ocular perfusion pressure and the effects of systemic and topical medications on it. We believe that the balance between IOP and BP, influenced by the autoregulatory capacity of the eye, is part of what determines whether an individual will develop optic nerve damage. However, prospective, longitudinal studies are needed to better define the role of ocular perfusion pressure in the development and progression of glaucoma. PMID:24238296

Costa, Vital P; Harris, Alon; Anderson, Douglas; Stodtmeister, Richard; Cremasco, Fernanda; Kergoat, Helene; Lovasik, John; Stalmans, Ingborg; Zeitz, Oliver; Lanzl, Ines; Gugleta, Konstantin; Schmetterer, Leopold

2014-06-01

352

[High Pressure Gas Tanks  

NASA Technical Reports Server (NTRS)

Four high-pressure gas tanks, the basis of this study, were especially made by a private contractor and tested before being delivered to NASA Kennedy Space Center. In order to insure 100% reliability of each individual tank the staff at KSC decided to again submit the four tanks under more rigorous tests. These tests were conducted during a period from April 10 through May 8 at KSC. This application further validates the predictive safety model for accident prevention and system failure in the testing of four high-pressure gas tanks at Kennedy Space Center, called Continuous Hazard Tracking and Failure Prediction Methodology (CHTFPM). It is apparent from the variety of barriers available for a hazard control that some barriers will be more successful than others in providing protection. In order to complete the Barrier Analysis of the system, a Task Analysis and a Biomechanical Study were performed to establish the relationship between the degree of biomechanical non-conformities and the anomalies found within the system on particular joints of the body. This relationship was possible to obtain by conducting a Regression Analysis to the previously generated data. From the information derived the body segment with the lowest percentage of non-conformities was the neck flexion with 46.7%. Intense analysis of the system was conducted including Preliminary Hazard Analysis (PHA), Failure Mode and Effect Analysis (FMEA), and Barrier Analysis. These analyses resulted in the identification of occurrences of conditions, which may be becoming hazardous in the given system. These conditions, known as dendritics, may become hazards and could result in an accident, system malfunction, or unacceptable risk conditions. A total of 56 possible dendritics were identified. Work sampling was performed to observe the occurrence each dendritic. The out of control points generated from a Weighted c control chart along with a Pareto analysis indicate that the dendritics "Personnel not Wearing Proper Protective and Hose/tubing located in high-traffic area" which account for 59.18% of total dendritic frequency need to be addressed to reduce the chance of a hazard from occurring. However, the occurrences of some dendritics are more important than others. As a result immediate, from a Weighted c perspective, corrective action should be taken to ameliorate the cause of the Class A dendritic "Personnel located under suspended or moving loads" rather than just the most commonly occurring dendritics. In any case the vast majority of data obtained indicates that testing operations possess a relatively high degree of safety.

Quintana, Rolando

2002-01-01

353

Centrifugal compressors handle high pressures  

Microsoft Academic Search

Applications for high-pressure centrifugal compressors include reinjection of gas associated with oil production or residue gas from NGL recovery into the producing formation. This application serves several purposes. It maintains oil-field pressure to obtain higher production rates and maintains gas-field pressures to maximize liquids recovery. Gas reinjection also conserves gas resources by eliminating flaring until the gas can be produced.

1979-01-01

354

High Pressure Thermodynamics of Mixtures  

Microsoft Academic Search

Abstract—In the present survey some important trends in the high pressure thermodynamics,of fluid mixtures of non-electrolytesare reviewed. First the pressure dependence,of excess functions such as the excess Gibbs energy GE, the excess enthalpy HE, the excess entropy SE and the excess heat capacity CE is discussed. It can be obtained from the knowledge,of the excess volume a function of pressure

G. M. Schneider

1976-01-01

355

Practical Management of Pressure Sores  

PubMed Central

Pressure sores are common in the debilitated elderly. Causal factors are unrelieved pressure, shearing forces, friction, and moisture. Preventive measures should be used for all high-risk patients, defined by general condition, mental status, degree of incontinence, amount of activity, and mobility. Principles of treating ulcers include pressure relief, reducing bacterial counts, debriding necrotic tissue, and providing a moist, clean environment. Imagesp2385-ap2389-ap2392-a

Jordan, John M.

1992-01-01

356

Measuring interface pressure: validity and reliability problems.  

PubMed

Health service providers rely on pressure-relieving and pressure-reducing products to prevent pressure ulcers. This review critically examines interface pressure measurements, most commonly used to evaluate patient support surfaces. PMID:14999994

Norman, D

2004-02-01

357

Transitional wall pressure fluctuations on axisymmetric bodies.  

PubMed

This paper reports the characteristics of wall pressure fluctuations in the transition region of the flow over axisymmetric bodies. Measurements are conducted in a low noise wind tunnel to obtain the boundary-layer flow field, the local static pressures, and the wall pressure fluctuations using hot wires, micromanometers and flush-mounted microphones. The spatial and the temporal developments of Tollmien-Schlichting (T-S) waves were first observed in the time domain. The wall pressure fluctuations in the transitional boundary-layer flows were of intermittent pulses and intensified as they were convected downstream at typically 63% of the upstream velocity. The Wigner-Ville distributions are then obtained to examine the energy evolution jointly in time and in frequency. The center frequency of the T-S wave is decreased with increases of the boundary-layer thickness and the bandwidth of the energy distribution is broadened as the local Reynolds number is increased. Finally the nondimensional spectra of the transitional wall pressure fluctuations scaled on the outer variables was obtained and it was then found that the characteristic frequency of the T-S wave was related to the outer variables as omegadelta( *)/U(infinity) approximately 0.2. The peak level of the pressure fluctuations during late transition at the characteristic frequency is about 10 dB higher than that of the fully developed flow. PMID:19045764

Hong, Chinsuk; Shin, Ku-Kyun; Jeon, Jae-Jin; Kim, Sang-Youn

2008-11-01

358

Bidirectional Pressure-Regulator System  

NASA Technical Reports Server (NTRS)

A bidirectional pressure-regulator system has been devised for use in a regenerative fuel cell system. The bidirectional pressure-regulator acts as a back-pressure regulator as gas flows through the bidirectional pressure-regulator in one direction. Later, the flow of gas goes through the regulator in the opposite direction and the bidirectional pressure-regulator operates as a pressure- reducing pressure regulator. In the regenerative fuel cell system, there are two such bidirectional regulators, one for the hydrogen gas and another for the oxygen gas. The flow of gases goes from the regenerative fuel cell system to the gas storage tanks when energy is being stored, and reverses direction, flowing from the storage tanks to the regenerative fuel cell system when the stored energy is being withdrawn from the regenerative fuel cell system. Having a single bidirectional regulator replaces two unidirectional regulators, plumbing, and multiple valves needed to reverse the flow direction. The term "bidirectional" refers to both the bidirectional nature of the gas flows and capability of each pressure regulator to control the pressure on either its upstream or downstream side, regardless of the direction of flow.

Burke, Kenneth; Miller, John R.

2008-01-01

359

Pressurized-thermal-shock tests  

SciTech Connect

Pressurized-thermal-shock experiments are required to validate methods of fracture analysis to establish the degree of conservatism or accuracy involved in predictions of flaw behavior under certain accident conditions. By using methods and facilities developed for this purpose we can simulate materials and loading regimes to evaluate the integrity of flawed reactor pressure vessels subjected to pressurized-thermal-shock transients. These accidents involve small-break loss-of-coolant accidents, steamline breaks, and other similar overcooling accident scenarios involving combined temperature and pressure transients.

Whitman, G.D.

1981-01-01

360

MAVRIC pressure sensor mounting apparatus  

NASA Technical Reports Server (NTRS)

Unsteady pressure sensor, holding sleeve, and mounting block with orifice. For MAVRIC I model test in the Transonic Dynamics Tunnel. Model for Aeroelastic Validation Research Involving Computation (MAVRIC).

2000-01-01

361

Nutrition systems for pressure suits.  

NASA Technical Reports Server (NTRS)

Nutrition systems were successfully developed in the Apollo Program for astronauts wearing pressure suits during emergency decompression situations and during lunar surface explorations. These nutrition systems consisted of unique dispensers, water, flavored beverages, nutrient-fortified beverages, and intermediate moisture food bars. The emergency decompression system dispensed the nutrition from outside the pressure suit by interfacing with a suit helmet penetration port. The lunar exploration system utilized dispensers stowed within the interior layers of the pressure suit. These systems could be adapted for provision of nutrients in other situations requiring the use of pressure suits.

Huber, C. S.; Heidelbaugh, N. D.; Rapp, R. M.; Smith, M. C., Jr.

1973-01-01

362

Pressure balance under hydrothermal conditions  

NASA Astrophysics Data System (ADS)

Low pressure, low temperature growth of potassium titanyl phosphate (KTP) crystals, the material of choice for certain kinds of laser eye surgery apparatus and other applications, requires hydrothermal growth in pressure balance noble metal cans. This paper discusses the problem of pressure balancing the Au cans used for hydrothermal KTP growth. The P-V-T behavior of the pressure balance medium (H2O) and the growth medium (KTP saturated K2HPO4) are described and the source of the 'dimples' in growth cans is explained and remediation strategies are suggested.

Laudise, R. A.; Bridenbaugh, P. M.; Iradi, T.

1994-06-01

363

The Accuracy of an Automasking Algorithm in Plantar Pressure Measurements  

Microsoft Academic Search

Masking algorithms provide a way to analyze plantar pressure parameters based on distinct anatomical regions of the foot.\\u000a No study has addressed their accuracy. The purpose of this study was to determine the accuracy of the Novel® ten-region standard\\u000a masking algorithm in both dynamic and static measurements in normal feet. Static and dynamic plantar pressure measurements\\u000a were collected from ten

Scott J. Ellis; Hill Stoecklein; Joseph C. Yu; Grisha Syrkin; Howard Hillstrom; Jonathan T. Deland

2011-01-01

364

Pressure operated circulation valve  

SciTech Connect

This patent describes a circulating valve for use in a tubing string in a wellbore traversing earth formations where the annulus between the tubing string and the well bore contains a liquid. It comprises a tubular mandrel assembly having an annular recess; a tubular sleeve assembly slidably mounted in the annular recess, the sleeve assembly including first and second sleeve member; a circulating port in the tubular mandrel assembly intermediate of the length of the annular recess; the sleeve members having overlapped portions and seal means cooperating with the sleeve member and the mandrel assembly for defining an annular chamber in fluid communication with the circular port in a first position on the mandrel assembly, the sleeve members being independently movable longitudinally of the mandrel assembly; first and second release means for respectively releasably connecting the first sleeve member and the second sleeve member to the tubular assembly and for releasably maintaining the annular chamber in fluid communication with the port in the first position; and one of the sleeve members being responsive to a pressure applied in the annular chamber for releasing one of the first and second releasable means so that the one sleeve member moves longitudinally to a second position for placing the interior of the tubular mandrel assembly in fluid communication through the port with the exterior about the sleeve member.

Cochran, C.B.

1991-09-17

365

Automated office blood pressure.  

PubMed

Manual blood pressure (BP) is gradually disappearing from clinical practice with the mercury sphygmomanometer now considered to be an environmental hazard. Manual BP is also subject to measurement error on the part of the physician/nurse and patient-related anxiety which can result in poor quality BP measurements and office-induced (white coat) hypertension. Automated office (AO) BP with devices such as the BpTRU (BpTRU Medical Devices, Coquitlam, BC) has already replaced conventional manual BP in many primary care practices in Canada and has also attracted interest in other countries where research studies using AOBP have been undertaken. The basic principles of AOBP include multiple readings taken with a fully automated recorder with the patient resting alone in a quiet room. When these principles are followed, office-induced hypertension is eliminated and AOBP exhibits a much stronger correlation with the awake ambulatory BP as compared with routine manual BP measurements. Unlike routine manual BP, AOBP correlates as well with left ventricular mass as does the awake ambulatory BP. AOBP also simplifies the definition of hypertension in that the cut point for a normal AOBP (< 135/85 mm Hg) is the same as for the awake ambulatory BP and home BP. This article summarizes the currently available evidence supporting the use of AOBP in routine clinical practice and proposes an algorithm in which AOBP replaces manual BP for the diagnosis and management of hypertension. PMID:22265230

Myers, Martin G; Godwin, Marshall

2012-05-01

366

Pressure boosting system  

SciTech Connect

Airco Industrial Gases in Claymont, DE, increased production capacity by replacing its aging air-separation plant with a new facility. Transporting nitrogen gas to pipeline customers was a major energy user. Because critical safety blanketing and purging are primary uses, the plant must receive a reliable, uninterrupted supply of gas. Six reciprocating compressors, rated at a total of about 4,000 hp, boosted the gas pressure to 550 psig before it entered the pipeline. Airco investigated energy-saving alternatives for the new installation. Plant officials ruled out replacing six old compressors with identical new ones. The mechanical energy losses inherent in using six machines and the product loss from gas escaping through seals on the multiple machines were significant efficiency considerations. A single reciprocating compressor would have operated efficiently, but a six-stage compressor, large enough to process the volume of gas produced by the plant's air-separation unit, would have cost more than $1 million. Airco installed a combination centrifugal/reciprocating compressor to boost the nitrogen gas from 1.5 psig to 550 psig.

Hobson, R. (Airco Industrial Gases, Claymont, DE (United States))

1993-01-01

367

Working under pressure: crisis management, pressure groups and the media  

Microsoft Academic Search

Crisis managers need to deal with special interest groups who place pressure on organizations over their performances and work procedures. Pressure groups can stimulate some crisis situations (for example, the Nestlé milk products boycott, the Brent Spar oil storage platform disposal crisis). Because the media is interested in gaining stories that attract audiences (Sherman, 1989) the media can also act

Robert Heath

1998-01-01

368

dc arc interruption in pressurized gasses  

SciTech Connect

The purpose of the study was to investigate the possibility of achieving (1) short interruption time and (2) minimum contact erosion in a dc circuit interrupter. Arc interruption tests were performed on a 100-A, 600-V dc contactor under atmospheres of argon dry air, nitrogen, helium and hydrogen, each at four pressures 0.17, 0.34, 0.52, and 0.69 MPa (25, 50, 75 and 100 psig). It was found that the average arcing time in helium and hydrogen was the shortest, and that in argon the longest for the circuit conditions used. The contact erosion in hydrogen was the worst, and that in argon the best for the contact materials used in the tests. The static pressure in the chamber did not appear to have much effect on the arc interruption phenomenon for the contactor and gas pressures used.

Chowdhuri,P.

1980-01-01

369

Micro ElectroMechanical System (MEMS) Pressure Sensor for Footwear  

Microsoft Academic Search

Footwear comprises a sole and a plurality of sealed cavities contained within the sole. The sealed cavities can be incorporated as deformable containers within an elastic medium, comprising the sole. A plurality of micro electro-mechanical system (MEMS) pressure sensors are respectively contained within the sealed cavity plurality, and can be adapted to measure static and dynamic pressure within each of

Deepesh K. Kholwadwala; Brandon R. Rohrer; Barry L. Spletzer; Paul C. Galambos; Jason W. Wheeler; Clinton G. Hobart; Richard C. Givler

2008-01-01

370

A Technique to Measure Eyelid Pressure Using Piezoresistive Sensors  

Microsoft Academic Search

In this paper, novel procedures were developed using a thin (0.17 mm) tactile piezoresistive pressure sensor mounted on a rigid contact lens to measure upper eyelid pressure. A hydrostatic calibration system was constructed, and the influence of conditioning (prestressing), drift (continued increasing response with a static load), and temperature variations on the response of the sensor were examined. To optimally

Brett A. Davis; Michael J. Collins; Leo G. Carney

2009-01-01

371

High-pressure and temperature investigations of energetic materials  

NASA Astrophysics Data System (ADS)

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

Gump, J. C.

2014-05-01

372

Intraocular pressure and progression of glaucomatous visual field loss  

Microsoft Academic Search

PURPOSE:To evaluate the relationship between intraocular pressure and visual field progression in patients with primary open-angle glaucoma.METHODS:We prospectively followed 113 patients with early to moderate glaucomatous field damage. Conventional automated static perimetry, high-pass resolution perimetry, and intraocular pressure measurements were carried out at 6-month intervals. The mean and the highest intraocular pressure in the follow-up were compared in stable and

Carlos Martínez-Belló; Balwantray C Chauhan; Marcelo T Nicolela; Terry A McCormick; Raymond P LeBlanc

2000-01-01

373

Pressure-induced polymerization in substituted acetylenes  

SciTech Connect

A fundamental understanding of shock-induced chemical reactions in organics is still lacking and there are limited studies devoted to determining reaction mechanisms, evolution of bonding, and effect of functional group substitutions. The fast timescale of reactions occurring during shock compression create significant experimental challenges (diagnostics) to fully quantify the mechanisms involved. Static compression combined with temperature provides a complementary route to investigate the equilibrium phase space and metastable intermediates under extreme P-T conditions. In this study, we present our results from our ongoing high pressure in situ synchrotron x-ray diffraction experiments on substituted acetylenes: tert-butyl acetylene [TBA: (CH{sub 3}){sub 3}-C=CH] and ethynyl trimethylsilane [ETMS: (CH{sub 3}){sub 3}-SiC=CH]. We observed that the onset pressure of chemical reactions (at room temperature) in these compounds is higher under static compression (TBA: 12 GPa and ETMS: 17.6 GPa) when compared to shock input pressures (TBA: 6.1 GPa and ETMS: 6.6 GPa). At elevated temperatures, reactivity was observed to occur at pressures comparable to shock conditions. The products were polymeric in nature, recovered to ambient conditions with little degradation.

Chellappa, Raja S.; Dattelbaum, Dana M.; Sheffield, Stephen; Robbins, David (LANL)

2012-04-10

374

Pressurized Lunar Rover (PLR)  

NASA Astrophysics Data System (ADS)

The objective of this project was to design a manned pressurized lunar rover (PLR) for long-range transportation and for exploration of the lunar surface. The vehicle must be capable of operating on a 14-day mission, traveling within a radius of 500 km during a lunar day or within a 50-km radius during a lunar night. The vehicle must accommodate a nominal crew of four, support two 28-hour EVA's, and in case of emergency, support a crew of six when near the lunar base. A nominal speed of ten km/hr and capability of towing a trailer with a mass of two mt are required. Two preliminary designs have been developed by two independent student teams. The PLR 1 design proposes a seven meter long cylindrical main vehicle and a trailer which houses the power and heat rejection systems. The main vehicle carries the astronauts, life support systems, navigation and communication systems, lighting, robotic arms, tools, and equipment for exploratory experiments. The rover uses a simple mobility system with six wheels on the main vehicle and two on the trailer. The nonpressurized trailer contains a modular radioisotope thermoelectric generator (RTG) supplying 6.5 kW continuous power. A secondary energy storage for short-term peak power needs is provided by a bank of lithium-sulfur dioxide batteries. The life support system is partly a regenerative system with air and hygiene water being recycled. A layer of water inside the composite shell surrounds the command center allowing the center to be used as a safe haven during solar flares. The PLR 1 has a total mass of 6197 kg. It has a top speed of 18 km/hr and is capable of towing three metric tons, in addition to the RTG trailer. The PLR 2 configuration consists of two four-meter diameter, cylindrical hulls which are passively connected by a flexible passageway, resulting in the overall vehicle length of 11 m. The vehicle is driven by eight independently suspended wheels. The dual-cylinder concept allows articulated as well as double Ackermann steering. The primary power of 8 kW is supplied by a dynamic isotope system using a closed Brayton cycle with a xenon-hydrogen mixture as the working fluid. pressurized. The shell of the main body is constructed of a layered carbon fiber/foam/Kevlar sandwich structure. %Included in the shell is a layer of water for radiation protection. The layer of water extends from the front of the rover over the crew compartment and creates a safe haven for the crew during a solar flare-up. The carbon fiber provides the majority of the strength and stiffness and the Kevlar provides protection from micrometeoroids. The Kevlar is covered with a gold foil and multi-layer insulation (MLI) to reduce radiation degradation and heat transfer through the wall. @A thin thermoplastic layer seals the fiber and provides additional strength.

Creel, Kenneth; Frampton, Jeffrey; Honaker, David; McClure, Kerry; Zeinali, Mazyar; Bhardwaj, Manoj; Bulsara, Vatsal; Kokan, David; Shariff, Shaun; Svarverud, Eric

375

Pressurized Lunar Rover (PLR)  

NASA Technical Reports Server (NTRS)

The objective of this project was to design a manned pressurized lunar rover (PLR) for long-range transportation and for exploration of the lunar surface. The vehicle must be capable of operating on a 14-day mission, traveling within a radius of 500 km during a lunar day or within a 50-km radius during a lunar night. The vehicle must accommodate a nominal crew of four, support two 28-hour EVA's, and in case of emergency, support a crew of six when near the lunar base. A nominal speed of ten km/hr and capability of towing a trailer with a mass of two mt are required. Two preliminary designs have been developed by two independent student teams. The PLR 1 design proposes a seven meter long cylindrical main vehicle and a trailer which houses the power and heat rejection systems. The main vehicle carries the astronauts, life support systems, navigation and communication systems, lighting, robotic arms, tools, and equipment for exploratory experiments. The rover uses a simple mobility system with six wheels on the main vehicle and two on the trailer. The nonpressurized trailer contains a modular radioisotope thermoelectric generator (RTG) supplying 6.5 kW continuous power. A secondary energy storage for short-term peak power needs is provided by a bank of lithium-sulfur dioxide batteries. The life support system is partly a regenerative system with air and hygiene water being recycled. A layer of water inside the composite shell surrounds the command center allowing the center to be used as a safe haven during solar flares. The PLR 1 has a total mass of 6197 kg. It has a top speed of 18 km/hr and is capable of towing three metric tons, in addition to the RTG trailer. The PLR 2 configuration consists of two four-meter diameter, cylindrical hulls which are passively connected by a flexible passageway, resulting in the overall vehicle length of 11 m. The vehicle is driven by eight independently suspended wheels. The dual-cylinder concept allows articulated as well as double Ackermann steering. The primary power of 8 kW is supplied by a dynamic isotope system using a closed Brayton cycle with a xenon-hydrogen mixture as the working fluid. A sodium-sulfur battery serves as the secondary power source. Excess heat produced by the primary power system and other rover systems is rejected by radiators located on the top of the rear cylinder. The total mass of the PLR 2 is 7015 kg. Simplicity and low total weight have been the driving principles behind the design of PLR 1. The overall configuration consists of a 7-m-long, 3-m-diameter cylindrical main vehicle and a two-wheeled trailer. The cylinder of the main body is capped by eight-section, faceted, semi-hemispherical ends. The trailer contains the RTG power source and is not pressurized. The shell of the main body is constructed of a layered carbon fiber/foam/Kevlar sandwich structure. Included in the shell is a layer of water for radiation protection. The layer of water extends from the front of the rover over the crew compartment and creates a safe haven for the crew during a solar flare-up. The carbon fiber provides the majority of the strength and stiffness and the Kevlar provides protection from micrometeoroids. The Kevlar is covered with a gold foil and multi-layer insulation (MLI) to reduce radiation degradation and heat transfer through the wall. A thin thermoplastic layer seals the fiber and provides additional strength.

Creel, Kenneth; Frampton, Jeffrey; Honaker, David; Mcclure, Kerry; Zeinali, Mazyar; Bhardwaj, Manoj; Bulsara, Vatsal; Kokan, David; Shariff, Shaun; Svarverud, Eric

1992-01-01

376

Coasts under pressure.  

PubMed

In most areas of the world, too many people live or play along the coast. Municipal and industrial wastes pollute coastal waters. Rivers spew erosion sediment and pollutants into these waters. Economic development is often the only management strategy for coastal zones, and economic development has little concern for resource degradation and watershed management. 53 countries have coastal management plans, but few have adequately implemented them. Almost 66% of the world's population lives within 150 km of the coast; by 2025, 75% will live as close to the coast. In the US, the coastal population has grown faster than that of the entire US, so that the population density is now almost 400 persons/sq m compared to 275 persons/sq m in 1960. Urbanization continues in the US coastal zones, where 7 of the 10 US largest cities exist. 94% of China's population lives in the eastern 3rd of the country. The population density along China's coast is more than 600/sq km. In Shanghai, it is more than 2000/sq km. Many people are moving from poorer provinces in the central and western regions to the economic free zones and special economic zones along the coast. At any moment, 30-60 million Chinese are moving. Most everyone in southeastern Asia, the Caribbean, and Latin America live in coastal areas. By 2025, the coastal zone between Rio de Janeiro and Sao Paulo will be all urbanized This is also occurring on Chile's coast between Valparaiso and Concepcion. The Mediterranean has the most overcrowded coastline in the developed world. Unchecked development could lead to continuous urban sprawl between Spain and Greece. Development pressures have caused a sizable decline in or a collapse of coastal fisheries. In Asia, all waters within 15 km of the coastline have been overfished. Coral reefs and mangrove forests are being destroyed with inadequate resources targeted for their protection. PMID:12287493

Hinrichsen, D

1994-01-01

377

Particle pressures in fluidized beds  

SciTech Connect

This is an experimental project to make detailed measurements of the particle pressures generated in fluidized beds. The focus lies in two principle areas: (1) the particle pressure distribution around single bubbles rising in a two-dimensional gas-fluidized bed and (2) the particle pressures measured in liquid-fluidized beds. This first year has largely been to constructing the experiments The design of the particle pressure probe has been improved and tested. A two-dimensional gas-fluidized bed has been constructed in order to measure the particle pressure generated around injected bubbles. The probe is also being adapted to work in a liquid fluidized bed. Finally, a two-dimensional liquid fluidized bed is also under construction. Preliminary measurements show that the majority of the particle pressures are generated in the wake of a bubble. However, the particle pressures generated in the liquid bed appear to be extremely small. Finally, while not directly associated with the particle pressure studies, some NERSC supercomputer time was granted alongside this project. This is being used to make large scale computer simulation of the flow of granular materials in hoppers.

Campbell, C.S.; Rahman, K.; Hu, X.; Jin, C.; Potapov, A.V.

1992-01-01

378

Pressure algometry in manual therapy  

Microsoft Academic Search

SUMMARY. The pressure pain threshold (PPT), i.e. the least stimulus intensity at which a subject perceives pain, was studied in 30 patients with chronic unilateral pain in the shoulder and arm region.Fourteen trigger points were investigated on both sides of the body using pressure algometry. Eight paravertebral points and six points in the shoulder and arm region were evaluated. Each

L. Vanderweeën; R. A. B. Oostendorp; P. Vaes; W. Duquet

1996-01-01

379

Atmospheric-pressure plasma technology  

Microsoft Academic Search

Major industrial plasma processes operating close to atmospheric pressure are discussed. Applications of thermal plasmas include electric arc furnaces and plasma torches for generation of powders, for spraying refractory materials, for cutting and welding and for destruction of hazardous waste. Other applications include miniature circuit breakers and electrical discharge machining. Non-equilibrium cold plasmas at atmospheric pressure are obtained in corona

U. Kogelschatz

2004-01-01

380

Medications for High Blood Pressure  

MedlinePLUS

... and Angiotensin II receptor blockers (ARBs), reduce blood pressure by relaxing blood vessels Beta blockers, which also cause the heart to ... nerve impulses from the brain to relax blood vessels Many people with high blood pressure may need more than one medication to reach ...

381

A dynamic pressure calibration standard  

NASA Technical Reports Server (NTRS)

A dynamic pressure calibration standard has been developed for calibrating flush diaphragm mounted pressure transducers. Pressures up to 20 kPa (3 psi) have been accurately generated over a frequency range of 50 to 1800 hz. The uncertainty of the standard is +/-5 pct to 5kPa (.75 psi) and +/-10 pct from 5 kPa (.75 psi) to 20 kPa (3 psi). The system consists of two conically shaped, aluminum columns, one 5 cm (2 in.) high for low pressures and another 11 cm (4.3 in.) high for higher pressures, each filled with a viscous fluid. A column is mounted on the armature of a vibration exciter which imparts a sinusoidally varying acceleration to the fluid column. Two pressure transducers mounted at the base of the column sense the sinusoidally varying pressure. This pressure is determined from measurements of the density of the fluid, the height of the fluid, and the acceleration of the column. A section of the taller column is filled with steel balls to control the damping of the fluid to extend its useful frequency range.

Schutte, P. C.; Cate, K. H.; Young, S. D.

1985-01-01

382

Fluid Pressure Measuring Device Interface.  

National Technical Information Service (NTIS)

A fluid pressure measuring device interface which may be used in a submersible platform or vehicle includes an interface chamber fluidly coupled to a conduit which leads to the fluid medium whose pressure is to be measured. The interface chamber encloses ...

D. W. French

1997-01-01

383

Electrokinetically pumped high pressure sprays  

DOEpatents

An electrokinetic pump capable of producing high pressure is combined with a nozzle having a submicron orifice to provide a high pressure spray device. Because of its small size, the device can be contained within medical devices such as an endoscope for delivering biological materials such as DNA, chemo therapeutic agents, or vaccines to tissues and cells.

Schoeniger, Joseph S. (Oakland, CA); Paul, Phillip H. (Livermore, CA); Schoeniger, Luke (Pittsford, NY)

2002-01-01

384

Electrokinetically pumped high pressure sprays  

DOEpatents

An electrokinetic pump capable of producing high pressure is combined with a nozzle having a submicron orifice to provide a high pressure spray device. Because of its small size, the device can be contained within medical devices such as an endoscope for delivering biological materials such as DNA, chemo therapeutic agents, or vaccines to tissues and cells.

Schoeniger, Joseph S. (Oakland, CA); Paul, Phillip H. (Livermore, CA); Schoeniger, Luke (Pittsford, NY)

2005-11-01

385

Microwave Atmospheric-Pressure Sensor  

NASA Technical Reports Server (NTRS)

Report describes tests of microwave pressure sounder (MPS) for use in satellite measurements of atmospheric pressure. MPS is multifrequency radar operating between 25 and 80 GHz. Determines signal absorption over vertical path through atmosphere by measuring strength of echoes from ocean surface. MPS operates with cloud cover, and suitable for use on current meteorological satellites.

Flower, D. A.; Peckham, G. E.; Bradford, W. J.

1986-01-01

386

Electrokinetic high pressure hydraulic system  

Microsoft Academic Search

A compact high pressure hydraulic pump having no moving mechanical parts for converting electric potential to hydraulic force is described. The electrokinetic pump, which can generate hydraulic pressures greater than 2,500 psi, can be employed to compress a fluid, either liquid or gas, and manipulate fluid flow. The pump is particularly useful for capillary-base systems. By combining the electrokinetic pump

P. H. Paul; D. J. Rakestraw

2000-01-01

387

Electrokinetic high pressure hydraulic system  

Microsoft Academic Search

A compact high pressure hydraulic pump having no moving mechanical parts for converting electric potential to hydraulic force. The electrokinetic pump, which can generate hydraulic pressures greater than 2500 psi, can be employed to compress a fluid, either liquid or gas, and manipulate fluid flow. The pump is particularly useful for capillary-base systems. By combining the electrokinetic pump with a

Phillip H. Paul; David J. Rakestraw

2000-01-01

388

Magnetospheric equilibrium with anisotropic pressure  

SciTech Connect

Self-consistent magnetospheric equilibrium with anisotropic pressure is obtained by employing an iterative metric method for solving the inverse equilibrium equation in an optimal flux coordinate system. A method of determining plasma parallel and perpendicular pressures from either analytic particle distribution or particle distribution measured along the satellite's path is presented. The numerical results of axisymmetric magnetospheric equilibrium including the effects of finite beta, pressure anisotropy, and boundary conditions are presented for a bi-Maxwellian particle distribution. For the isotropic pressure cases, the finite beta effect produces an outward expansion of the constant magnetic flux surfaces in relation to the dipole field lines, and along the magnetic field the toroidal ring current is maximum at the magnetic equator. The effect of pressure anisotropy is found to further expand the flux surfaces outward. Along the magnetic field lines the westward ring current can be peak away from the equator due to an eastward current contribution resulting from pressure anisotropy. As pressure anisotropy increases, the peak westward current can become more singular. The outer boundary flux surface has significant effect on the magnetospheric equilibrium. For the outer flux boundary resembling dayside compressed flux surface due to solar wind pressure, the deformation of the magnetic field can be quite different from that for the outer flux boundary resembling the tail-like surface. 23 refs., 17 figs.

Cheng, C.Z.

1991-07-01

389

Pressure Energy and Bernoulli's Principle  

Microsoft Academic Search

An effort is made to show that the concept of pressure in an incompressible fluid as energy per unit volume possessed by the fluid is an erroneous one, and that Bernoulli's equation is not to be interpreted as a statement of conservation of energy, but rather as a relation between pressure, velocity, and height in the gravitational field.

George A. Lindsay

1952-01-01

390

49 CFR 192.197 - Control of the pressure of gas delivered from high-pressure distribution systems.  

Code of Federal Regulations, 2010 CFR

... 2010-10-01 false Control of the pressure of gas delivered...Components § 192.197 Control of the pressure of gas delivered... (3) A valve seat made of resilient material designed to withstand...with no external static or control lines. (b) If...

2010-10-01

391

49 CFR 192.197 - Control of the pressure of gas delivered from high-pressure distribution systems.  

Code of Federal Regulations, 2010 CFR

... 2009-10-01 false Control of the pressure of gas delivered...Components § 192.197 Control of the pressure of gas delivered... (3) A valve seat made of resilient material designed to withstand...with no external static or control lines. (b) If...

2009-10-01

392

Low-pressure wellhead for high-pressure stimulation  

SciTech Connect

Maturity of US Producing wells and constrained economics dictate careful planning and strict attention to details to optimize workover and recompletion operations. One aspect of operations that can significantly reduce costs is planned preparation of a wellheat for high-pressure stimulation. Historically, there have been four basic approaches to solving old wellhead configuration problems to prepare for high-pressure stimulation down casing. Some recent technical developments may provide a lower-cost solution. A casing spool is now available that features an external casing seal that cannot be pumped out. This seal is extremely reliable and has functioned on many extreme-pressure (15,000-psi) jobs without a single failure. Having the seal installed in a frac spool'' is very important because it provides convenient adaption from the low-pressure casing hanger to high-pressure control equipment with safety and reliability. Casing hanger seals are isolated from the harsh stimulation environment. While the newly available spool discussed above provides a partial solution to the low-pressure-wellhead/high-pressure-stimulation problem, valve performance must also be considered. Recent improvements in gate-valve design have produced a valve that meets all required performance criteria for efficient stimulation operations. The new frac valve'' features low maintenance with close tolerances on gate/seal surfaces, low operating torque, high corrosion and erosion resistance, sealing in both directions, and generally high performance in functionality.

Garvin, T.

1994-05-01

393

Pressurized lunar rover  

NASA Astrophysics Data System (ADS)

The pressurized lunar rover (PLR) consists of a 7 m long, 3 m diameter cylindrical main vehicle and a trailer which houses the power and heat rejection systems. The main vehicle carries the astronauts, life support systems, navigation and communication systems, directional lighting, cameras, and equipment for exploratory experiments. The PLR shell is constructed of a layered carbon-fiber/foam composite. The rover has six 1.5 m diameter wheels on the main body and two 1.5 m diameter wheels on the trailer. The wheels are constructed of composites and flex to increase traction and shock absorption. The wheels are each attached to a double A-arm aluminum suspension, which allows each wheel 1 m of vertical motion. In conjunction with a 0.75 m ground clearance, the suspension aids the rover in negotiating the uneven lunar terrain. The 15 N-m torque brushless electric motors are mounted with harmonic drive units inside each of the wheels. The rover is steered by electrically varying the speeds of the wheels on either side of the rover. The PLR trailer contains a radiosotope thermoelectric generator providing 6.7 kW. A secondary back-up energy storage system for short-term high-power needs is provided by a bank of batteries. The trailer can be detached to facilitate docking of the main body with the lunar base via an airlock located in the rear of the PLR. The airlock is also used for EVA operation during missions. Life support is a partly regenerative system with air and hygiene water being recycled. A layer of water inside the composite shell surrounds the command center. The water absorbs any damaging radiation, allowing the command center to be used as a safe haven during solar flares. Guidance, navigation, and control are supplied by a strapdown inertial measurement unit that works with the on-board computer. Star mappers provide periodic error correction.

Creel, Kenneth; Frampton, Jeffrey; Honaker, David; McClure, Kerry; Zeinali, Mazyar

1992-05-01

394

Pressurized lunar rover  

NASA Technical Reports Server (NTRS)

The pressurized lunar rover (PLR) consists of a 7 m long, 3 m diameter cylindrical main vehicle and a trailer which houses the power and heat rejection systems. The main vehicle carries the astronauts, life support systems, navigation and communication systems, directional lighting, cameras, and equipment for exploratory experiments. The PLR shell is constructed of a layered carbon-fiber/foam composite. The rover has six 1.5 m diameter wheels on the main body and two 1.5 m diameter wheels on the trailer. The wheels are constructed of composites and flex to increase traction and shock absorption. The wheels are each attached to a double A-arm aluminum suspension, which allows each wheel 1 m of vertical motion. In conjunction with a 0.75 m ground clearance, the suspension aids the rover in negotiating the uneven lunar terrain. The 15 N-m torque brushless electric motors are mounted with harmonic drive units inside each of the wheels. The rover is steered by electrically varying the speeds of the wheels on either side of the rover. The PLR trailer contains a radiosotope thermoelectric generator providing 6.7 kW. A secondary back-up energy storage system for short-term high-power needs is provided by a bank of batteries. The trailer can be detached to facilitate docking of the main body with the lunar base via an airlock located in the rear of the PLR. The airlock is also used for EVA operation during missions. Life support is a partly regenerative system with air and hygiene water being recycled. A layer of water inside the composite shell surrounds the command center. The water absorbs any damaging radiation, allowing the command center to be used as a safe haven during solar flares. Guidance, navigation, and control are supplied by a strapdown inertial measurement unit that works with the on-board computer. Star mappers provide periodic error correction. The PLR is capable of voice, video, and data transmission. It is equipped with two 5 W X-band transponder, allowing simultaneous transmission and reception. An S-band transponder is used to communicate with the crew during EVA. The PLR has a total mass of 6197 kg. It has a nominal speed of 10 km/hr and a top speed of 18 km/hr. The rover is capable of towing 3 metric tons (in addition to the RTG trailer).

Creel, Kenneth; Frampton, Jeffrey; Honaker, David; Mcclure, Kerry; Zeinali, Mazyar

1992-01-01

395

MOEMS pressure sensors for propulsion applications  

NASA Astrophysics Data System (ADS)

Pressure sensors utilizing MEMS technology for fabrication of the sensing element, interrogation by fiber optics, and which are suitable for propulsion applications are described. Devices utilizing micro-opto-electro-mechanical systems (MOEMS) technology are often better suited for harsh environments than electrically interrogated MEMS devices, so with sturdy packaging these optical devices may be useful to many propulsion applications. MOEMS pressure sensors can also be incorporated into arrays for detailed spatial characterization along with inherent high speed temporal characterization. Such characterization is expected to be very useful for propulsion systems. This presentation will first review optical-MEMS pressure sensor configurations. We will then concentrate on configurations most suitable for high speed applications in harsh environments. Examples of experimental results for static pressure test as well as for dynamic pressure test carried out in a shock tube demonstrating good linearity, sensitivity and time response will then be presented. Hybrid and monolithic array configurations will be presented. A discussion of the use of wavelength division multiplexing for efficient accessing of array elements will also be included.

Boyd, Joseph T.; Dasgupta, Samhita; Jackson, Howard E.

2000-08-01

396

Model for the Space Shuttle Main Engine High Pressure Oxidizer Turbopump Shaft Seal System.  

National Technical Information Service (NTIS)

A simple static model is presented which solves for the flow properties of pressure, temperature, and mass flow in the Space Shuttle Main Engine pressure Oxidizer Turbopump Shaft Seal Systems. This system includes the primary and secondary turbine seals, ...

D. E. Paxson

1990-01-01

397

Plasma pressure in the magnetosphere  

NASA Astrophysics Data System (ADS)

The plasma pressure distribution is essential for computing magnetospheric currents and for magnetosphere-ionosphere coupling. However, the 3D pressure distribution in the magnetosphere is relatively unknown because most in-situ observations are either in the ionosphere or the plasma sheet. With the assumption of isotropy (pressure constant along the field line) there have been attempts to obtain the pressure at different location either by mapping observed data (e.g. in the ionosphere) along the field lines based on empirical magnetospheric models to the equator. Another approach is to compute a pressure profile in the equtorial plane (2D) or along sun-earth axis (1D) that is in force balance with the magnetic stresses of an empirical model. However, the pressure distribution obtained from these methods are usually not in force balance with the empirical magnetic field at different location. Thus, in order to obtain 3D pressure distribution in force balance with the magnetic field we have developed a MAG-3D code to solve the 3D force balance equation J × B = nabla P. Our calculation is performed in a flux coordinate system in which the magnetic field is expressed in terms of Euler potentials by B = nabla ? × nabla ?. The pressure distribution, P = P(?,?), is prescribed in either the equatorial plane or the ionosphere based on satellite measurement. In addition, boundary conditions for ? surfaces are imposed using empirical magnetic field models. Our results provide 3D distributions of magnetic field, pressure as well as parallel and perpendicular currents for both quiet time and disturbed magnetospheric conditions.

Cheng, C.; Zaharia, S.

398

Pressure Systems Energy Release Protection (Gas Pressurized Systems)  

NASA Technical Reports Server (NTRS)

A survey of studies into hazards associated with closed or pressurized system rupture and preliminary guidelines for the performance design of primary, secondary, and protective receptors of these hazards are provided. The hazards discussed in the survey are: blast, fragments, ground motion, heat radiation, biological, and chemical. Performance guidelines for receptors are limited to pressurized systems that contain inert gas. The performance guidelines for protection against the remaining unaddressed degenerative hazards are to be covered in another study.

Brown, S. J. (editor)

1986-01-01

399

Graphene based piezoresistive pressure sensor  

NASA Astrophysics Data System (ADS)

We present a pressure sensor based on the piezoresistive effect of graphene. The sensor is a 100 nm thick, 280 ?m wide square silicon nitride membrane with graphene meander patterns located on the maximum strain area. The multilayer, polycrystalline graphene was obtained by chemical vapor deposition. Strain in graphene was generated by applying differential pressure across the membrane. Finite element simulation was used to analyze the strain distribution. By performing electromechanical measurements, we obtained a gauge factor of ~1.6 for graphene and a dynamic range from 0 mbar to 700 mbar for the pressure sensor.

Zhu, Shou-En; Krishna Ghatkesar, Murali; Zhang, Chao; Janssen, G. C. A. M.

2013-04-01

400

High pressure pulsed capillary viscometry  

NASA Technical Reports Server (NTRS)

An analytical and test program was conducted in order to establish the feasibility of a multichamber pulsed-capillary viscometer. The initial design incorporated a piston, ram, and seals which produced measured pulses up to 30,000 psi in the closed chamber system. Pressure pulses from one to ten milliseconds were investigated in a system volume of 1 cuin. Four test fluids: a MIL-L-7808, a 5P4E polyphenyl ether, a MIL-L-23699A, and a synthetic hydrocarbon were examined in the test pressure assembly. The pressure-viscosity coefficient and viscosity delay time were determined for the MIL-L-7808 lubricant tested.

Smith, R. L.; Walowitt, J. A.; Pan, C. H. T.

1972-01-01

401

Electrokinetic high pressure hydraulic system  

DOEpatents

A compact high pressure hydraulic pump having no moving mechanical parts for converting electric potential to hydraulic force. The electrokinetic pump, which can generate hydraulic pressures greater than 2500 psi, can be employed to compress a fluid, either liquid or gas, and manipulate fluid flow. The pump is particularly useful for capillary-base systems. By combining the electrokinetic pump with a housing having chambers separated by a flexible member, fluid flow, including high pressure fluids, is controlled by the application of an electric potential, that can vary with time.

Paul, Phillip H. (Livermore, CA); Rakestraw, David J. (Fremont, CA)

2000-01-01

402

Gas Hydrate and Pore Pressure  

NASA Astrophysics Data System (ADS)

Many efforts have been devoted to quantify excess pore pressures related to gas hydrate dissociation in marine sediments below the BSR using several approaches. Dissociation of gas hydrates in proximity of the BSR, in response to a change in the physical environment (i.e., temperature and/or pressure regime), can liberate excess gas incrising the local pore fluid pressure in the sediment, so decreasing the effective normal stress. So, gas hydrate dissociation may lead to excess pore pressure resulting in sediment deformation or failure, such as submarine landslides, sediment slumping, pockmarks and mud volcanoes, soft-sediment deformation and giant hummocks. Moreover, excess pore pressure may be the result of gas hydrate dissociation due to continuous sedimentation, tectonic uplift, sea level fall, heating or inhibitor injection. In order to detect the presence of the overpressure below the BSR, we propose two approachs. The fist approach models the BSR depth versus pore pressure; in fact, if the free gas below the BSR is in overpressure condition, the base of the gas hydrate stability is deeper with respect to the hydrostatic case. This effect causes a discrepancy between seismic and theoretical BSR depths. The second approach models the velocities versus gas hydrate and free gas concentrations and pore pressure, considering the approximation of the Biot theory in case of low frequency, i.e. seismic frequency. Knowing the P and S seismic velocity from seismic data analysis, it is possibile to jointly estimate the gas hydrate and free gas concentrations and the pore pressure regime. Alternatively, if the S-wave velocity is not availbale (due to lack of OBS/OBC data), an AVO analysis can be performed in order to extract information about Poisson ratio. Our modeling suggests that the areas characterized by shallow waters (i.e., areas in which human infrastructures, such as pipelines, are present) are significantly affected by the presence of overpressure condition. Moreover, the knoweledge of seismic velocities can be considered an powerful tool to detect the overpressure in case that the pore pressure is equal to the hydrostatic pressure plus the 50% of the difference between the lithostatic and the hydrostatic pressure. In conclusions, an accurate analysis of the BSR nature and the pore pressure are required to improve the reliability of the gas-phase estimation for different target, such as gas hydrate and free gas exploitations and environmental studies.

Tinivella, Umberta; Giustiniani, Michela

2014-05-01

403

Graphite filament wound pressure vessels  

NASA Technical Reports Server (NTRS)

Filament wound NOL rings, 4-inch and 8-inch diameter closed-end vessels involving three epoxy resin systems and three graphite fibers were tested to develop property data and fabrication technology for filament wound graphite/epoxy pressure vessels. Vessels were subjected to single-cycle burst tests at room temperature. Manufacturing parameters were established for tooling, winding, and curing that resulted in the development of a pressure/vessel performance factor (pressure x volume/weight) or more than 900,000 in. for an oblate spheroid specimen.

Feldman, A.; Damico, J. J.

1972-01-01

404

Pressure sensor for sealed containers  

DOEpatents

A magnetic pressure sensor for sensing a pressure change inside a sealed container. The sensor includes a sealed deformable vessel having a first end attachable to an interior surface of the sealed container, and a second end. A magnet mounted to the vessel second end defining a distance away from the container surface provides an externally detectable magnetic field. A pressure change inside the sealed container causes deformation of the vessel changing the distance of the magnet away from the container surface, and thus the detectable intensity of the magnetic field.

Hodges, Franklin R. (Loudon, TN)

2001-01-01

405

Pressure Spectrum in Homogeneous Turbulence  

NASA Astrophysics Data System (ADS)

The pressure spectrum in homogeneous steady turbulence is studied using direct numerical simulation with resolution up to 10243 and the Reynolds number R? between 38 and 478. The energy spectrum is found to have a finite inertial range with the Kolmogorov constant K = 1.65+/-0.05 followed by a bump at large wave numbers. The pressure spectrum in the inertial range is found to be approximately P\\(k\\) = Bp?¯4/3k-7/3 with Bp = 8.0+/-0.5, and followed by a bump of nearly k-5/3 at higher wave numbers. Universality and a new scaling of the pressure spectrum are discussed.

Gotoh, Toshiyuki; Fukayama, Daigen

2001-04-01

406

Thin polyethylene pressure sensitive labels  

US Patent & Trademark Office Database

The invention is directed to an ultra thin pressure sensitive adhesive construction suitable for the high speed application of label mounting equipment. The labels include a polyethylene film having a density of from 0.917 to 0.924 g/cm.sup.3 and a thickness of less than 1.8 mils; a pressure sensitive adhesive on one surface of the film; and a release composition coated paper liner having a thickness of less than 2.2 mils releasaby attached to the pressure sensitive adhesive.

2008-07-15

407

Measurement of pulse pressure in plasma by crusher gauge  

SciTech Connect

Results are presented of pressure measurements in the plasma of a stabilized pinched discharge with axial blow through of the current channel by plasma using static and dynamic methods for crusher gauge calibration. Accuracies for maximum pressure measurements for both calibration methods are evaluated. The dynamic properties of the crusher gauge are taken into account experimentally in studying pulse forces and pressures in the 1-100 MPa range for times of 10/sup /minus/5/ to 10/sup /minus/3/ seconds. A piezoelectric method and device for dynamic calibration of the pressure gauges is described.

Kalachnikov, E.V.; Rogovtsev, P.N.

1988-06-01

408

Micro Electro-Mechanical System (MEMS) Pressure Sensor for Footwear  

DOEpatents

Footwear comprises a sole and a plurality of sealed cavities contained within the sole. The sealed cavities can be incorporated as deformable containers within an elastic medium, comprising the sole. A plurality of micro electro-mechanical system (MEMS) pressure sensors are respectively contained within the sealed cavity plurality, and can be adapted to measure static and dynamic pressure within each of the sealed cavities. The pressure measurements can provide information relating to the contact pressure distribution between the sole of the footwear and the wearer's environment.

Kholwadwala, Deepesh K. (Albuquerque, NM); Rohrer, Brandon R. (Albuquerque, NM); Spletzer, Barry L. (Albuquerque, NM); Galambos, Paul C. (Albuquerque, NM); Wheeler, Jason W. (Albuquerque, NM); Hobart, Clinton G. (Albuquerque, NM); Givler, Richard C. (Albuquerque, NM)

2008-09-23

409

High pressure synthesis gas fermentation  

SciTech Connect

The construction of the high pressure gas phase fermentation system has been completed. Photographs of the various components of the system are presented, along with an operating procedure for the equipment.

Not Available

1992-01-01

410

Kerogen Decomposition under Elevated Pressures.  

National Technical Information Service (NTIS)

A series of experiments on oil shale retorting have been carried out under both isothermal and nonisothermal conditions and at different pressures. The produced shale oil was separated into five individual components: Polar, Weak Polar, Saturates, Aromati...

R. D. Noble C. C. Wang

1981-01-01

411

Apparatus for Controlling Pressure Recovery.  

National Technical Information Service (NTIS)

An apparatus for controlling fluid pressure recovery includes an elongated housing having an opening at a first end thereof, an opening at a second end thereof, an inner peripheral surface, and a fluid flow passageway therethrough. The apparatus further i...

S. A. Jordan

2001-01-01

412

Intraocular pressure reduction and regulation  

NASA Technical Reports Server (NTRS)

System designed to reduce intraocular pressure hydraulically to any level desired by physician over set time and in controlled manner has number of uses in ophthalmology. Device may be most immediately useful in treatment of glaucoma.

Baehr, E. F.; Mcgannon, W. J.

1979-01-01

413

High Pressure Particulate Physics Facility.  

National Technical Information Service (NTIS)

This report documents the initial development of the High Pressure Particulate Physics (HP3) facility. The facility is anticipated to allow precision impact of two flat plates at a very high degree of precision with minimal misalignment when completed. A ...

L. C. Chhabildas W. L. Cooper W. R. Maines

2011-01-01

414

Electrokinetic high pressure hydraulic system  

DOEpatents

An electrokinetic high pressure hydraulic pump for manipulating fluids in capillary-based systems. The pump uses electro-osmotic flow to provide a high pressure hydraulic system, having no moving mechanical parts, for pumping and/or compressing fluids, for providing valve means and means for opening and closing valves, for controlling fluid flow rate, and manipulating fluid flow generally and in capillary-based systems (Microsystems), in particular. The compact nature of the inventive high pressure hydraulic pump provides the ability to construct a micro-scale or capillary-based HPLC system that fulfills the desire for small sample quantity, low solvent consumption, improved efficiency, the ability to run samples in parallel, and field portability. Control of pressure and solvent flow rate is achieved by controlling the voltage applied to an electrokinetic pump.

Paul, Phillip H. (Livermore, CA); Rakestraw, David J. (Fremont, CA); Arnold, Don W. (Livermore, CA); Hencken, Kenneth R. (Pleasanton, CA); Schoeniger, Joseph S. (Oakland, CA); Neyer, David W. (Castro Valley, CA)

2001-01-01

415

Calibrated clamp facilitates pressure application  

NASA Technical Reports Server (NTRS)

Spring-loaded clamp applies specific pressure to hold materials together during bonding, welding, and machining. The clamp has two adjustable legs terminating in suction cups for easy attachment to a surface.

1966-01-01

416

High Pressure Industrial Water Facility  

NASA Technical Reports Server (NTRS)

In conjunction with Space Shuttle Main Engine testing at Stennis, the Nordberg Water Pumps at the High Pressure Industrial Water Facility provide water for cooling the flame deflectors at the test stands during test firings.

1992-01-01

417

Fast pressure-sensor system  

NASA Technical Reports Server (NTRS)

Miniature silicon-diaphragm sensors and signal multiplexer are mounted to ganged zero-operate-calibrate pressure selector switches. Device allows in-situ calibration, can be computer controlled, and measures at approximately 10,000 readings per second.

Gross, C.

1976-01-01

418

Fluid pressure actuated perforating gun  

SciTech Connect

A well perforating gun assembly includes a perforating gun secured to the bottom of a tubular actuating housing containing a fluid pressure actuated hammer and a fixedly mounted primer against which the firing means is impacted. A latch normally maintains the firing means in an elevated position with respect to the primer but such latch may be released through the application of sufficient fluid pressure force to the firing means to drive it into engagement with the primer. If the primer fails to ignite, a second fluid pressure force is employed to move the firing means to its original latched position, ready for a second application of fluid pressure to release the firing means and again impact the primer.

Peterson, E. R.

1985-07-30

419

Blood Pressure Monitoring at Home  

MedlinePLUS

... manual, depending on the model. This blood pressure monitoring device is good for hearing-impaired patients, since there is no need to listen to heart sounds through the stethoscope. A disadvantage of the digital ...

420

Design for Pressure Regulating Components.  

National Technical Information Service (NTIS)

The design development for Pressure Regulating Components included a regulator component trade-off study with analog computer performance verification to arrive at a final optimized regulator configuration for the Space Storable Propulsion Module, under d...

H. Wichmann

1973-01-01

421

Inertia of dynamic pressure arrays  

NASA Technical Reports Server (NTRS)

From earlier measurements and the mathematical examples, it can be gathered that the inertia of dynamic pressure arrays can be computed with sufficient accuracy and the proper size of tubing established, provided that certain requirements are made on the inertia.

Weidemann, Hans

1941-01-01

422

Common pressure vessel battery performance  

NASA Technical Reports Server (NTRS)

Performance tests run on two common pressure vessel type nickel hydrogen batteries are described and the results presented. The study included: (1) charge retention tests, (2) synchronous eclipse season cycling tests, and (3) temperature differential tests.

Otzinger, B.

1978-01-01

423

Effect of Ram-jet Pressure Pulsations on Supersonic-diffuser Performance  

NASA Technical Reports Server (NTRS)

Experimental study of effects of combustion roughness and controlled mechanical oscillations on diffuser operation was conducted on an 8-inch ram jet at Mach number 1.87. Within experimental accuracy, the optimum mean combustion-chamber static pressure occurred when the maximum instantaneous static pressure equalled the optimum steady-flow value and the corresponding decrement in optimum mean static pressure was equal to one-half the total amplitude of the pressure pulsations. A marked attenuation of amplitude of cold-buzz pressure fluctuations was effected over limited range of subcritical diffuser operation by means of properly tuned rotating disk located in combustion chamber.

Connors, James F

1950-01-01

424

Fixture for Pressure Testing Sight Glasses.  

National Technical Information Service (NTIS)

A fixture for pressure testing sight glasses includes a base having a recessed pressure chamber therein, a peripheral seal ring in the pressure chamber and a supply passage for supplying a pressurized fluid to the pressure chamber. The test fixture is ope...

E. S. Nickerson

1992-01-01

425

High Blood Pressure and Metabolic Syndrome  

MedlinePLUS

... Pressure High Blood Pressure Tools & Resources Stroke More High Blood Pressure and Metabolic Syndrome Updated:Aug 27,2012 Metabolic ... content was last reviewed on 04/04/2012. High Blood Pressure • Home • About High Blood Pressure (HBP) Introduction What ...

426

Pressure Modulator Radiometer (PMR) tests  

NASA Technical Reports Server (NTRS)

The pressure modulator technique was evaluated for monitoring pollutant gases in the Earth's atmosphere of altitude levels corresponding to the mid and lower troposphere. Using an experimental set up and a 110 cm sample cell, pressure modulator output signals resulting from a range of gas concentrations in the sample cell were examined. Then a 20 cm sample cell was modified so that trace gas properties in the atmosphere could be simulated in the laboratory. These gas properties were measured using an infrared sensor.

Odell, E. L. G.; Cosmi, F. M.; Kreft, A. E.; Racette, G. W.; Maresca, T. J.; Pancoast, F. O.; Rutecki, D. J.; Yager, W. C.

1979-01-01

427

CC Cryostat Vapor Pressure Thermometers  

SciTech Connect

Vapor pressure thermometers will be used to measure the temperature or the liquid argon in the cryostat at two different levels. One bulb will be positioned near the top of the vessel, and a second bulb will be located near the bottom of the vessel. The volume of the bulbs is dependent upon the charge temperature and pressure chosen, the temperature range of the thermometer desired, the size and length of tubing used, and the warm volume involved.

Kurita, C.H.; /Fermilab

1987-10-01

428

Atmospheric pressure plasma jet applications  

Microsoft Academic Search

Summary form only given. The atmospheric pressure plasma jet (APPJ) is a non-thermal, high pressure plasma discharge that produces a high velocity effluent stream of highly reactive chemical species. The discharge operates on a feedstock gas (e.g. He\\/O2\\/H2 O) which flows between two concentric cylindrical electrodes: an outer grounded electrode and an inner electrode powered at 13.56 MHz RF. While

H. W. Herrmann; L. Henins; G. S. Selwyn

1998-01-01

429

Indirect blood pressure measuring device  

NASA Technical Reports Server (NTRS)

Design and performance of a blood pressure recording device for pediatric use are reported. A strain gage transducer with a copper-beryllium strip as force sensing element is used to monitor skin movements and to convert them into electrical signals proportional to those displacements. Experimental tests with this device in recording of force developed above the left femoral artery of a dog accurately produced a blood pressure curve.

Hum, L.; Cole, C. E.

1973-01-01

430

Extrusion energy and pressure requirements  

SciTech Connect

Corn gluten meal samples at moisture contents of 14, 20 and 26% dry basis were extruded at barrel temperatures of 120, 145 and 170/sup 0/C with screw speeds of 100, 150 and 200 rpm. The specific energy requirements and specific operating pressure decreases as the moisture content and temperature were increased. The effect of screw speed on specific energy and pressure was inconclusive.

Bhattacharya, M.; Hanna, M.A.

1984-01-01

431

Hydrogen at extreme pressures (Review Article)  

NASA Astrophysics Data System (ADS)

Here we review recent experimental and theoretical studies of hydrogen approaching metallization regime. Experimental techniques have made great advances over the last several years making it possible to reach previously unachievable conditions of pressure and temperature and to probe hydrogen at these conditions. Theoretical methods have also greatly improved; exemplified through the prediction of new structural and ordered quantum states. Recently, a new solid phase of hydrogen, phase IV, has been discovered in a high-pressure high-temperature domain. This phase is quite unusual structurally and chemically as it represents an intermediate state between common molecular and monatomic configurations. Moreover, it shows remarkable fluxional characteristics related to its quantum nature, which makes it unique among the solid phases, even of light elements. However, phase IV shows the presence of a band gap and exhibits distinct phonon and libron characteristic of classical solids. The quantum behavior of hydrogen in the limit of very high pressure remains an open question. Prospects of studying hydrogen at more extreme conditions by static and combined static-dynamic methods are also presented.

Goncharov, Alexander F.; Howie, Ross T.; Gregoryanz, Eugene

2013-05-01

432

MEASURING INTERSTITIAL FLUID PRESSURE WITH FIBEROPTIC PRESSURE TRANSDUCERS  

PubMed Central

In this report we describe a practical procedure for measuring interstitial fluid pressure (IFP) using fiberoptic pressure transducers based on optical interferometry. Eight mice were used for subcutaneous IFP measurements and four mice for intramuscular IFP measurements with a FOBPS-18 fiberoptic pressure transducer. We used four mice for subcutaneous IFP measurements with a SAMBA-420 MR fiberoptic pressure transducer. One measurement was made for each mouse simultaneously by using a fiberoptic system and an established approach, either transducer-tipped catheter or wick-in-needle technique. The mean IFP values obtained in subcutaneous tissues were ?3.00 mm Hg (SEM ?/+?0.462, n=8), ?3.25 mmHg (SEM ?/+ 0.478, n=4), ?3.34mm Hg (SEM?/+ 0.312, n=6), and ?2.85 (SEM ?/+ 0.57, n= 6) for the FOBPS fiberoptic transducer, the SAMBA fiberoptic transducer, the transducer-tipped catheter, and the wick-in–needle technique, respectively. There was no difference between these techniques to measure IFP (Friedman test, p=0.7997). The subcutaneous IFP measurements showed strong linear correlation between fiberoptic transducer and transducer-tipped catheter (R2= 0.9950) and fiberoptic transducer and wick–in-needle technique (R2= 0.9966). Fiberoptic pressure transducers measure the interstitial fluid pressure accurately, comparable to conventional techniques. The simplified IFP measurement procedures described in this report will allow investigators to easily measure IFP, and elucidate the unit pressure change per unit volume change (dP/dV) in normal or cancer tissues in the presence of strong electromagnetic fields encountered in MRI.

Ozerdem, Ugur

2008-01-01

433

Measuring the pressure in ultrahigh-pressure mercury arcs  

SciTech Connect

Ultrahigh-pressure (UHP) mercury lamps are important as high-brightness light sources for digital projection. Hg pressures are usually above 20 MPa and difficult to measure. We have built special UHP lamps with a liquid Hg condensate in a temperature-controlled reservoir, allowing us to tune the Hg vapor pressure p between 14 and 30 MPa. As a simple measure for p, we recorded the width DELTAlambda of the 546 nm Hg line while varying p and also the lamp current I and voltage U. The data define a function p(DELTAlambda,I,U) that will deliver p to better than 3% from simple measurements of DELTAlambda, I, and U for most UHP lamps in the important 100-200 W power range. The method is applied to sample lamps, yielding pressures up to 26 MPa and demonstrating how filled Hg amount, burning position, arc gap, and lamp power affect the pressure. The effective temperature of typical UHP lamps is found to be 2400 K. We also derive an improved characteristic U(d,p,I) for the dependence of the arc voltage on arc gap, pressure, and current for electrode-stabilized Hg discharges in the UHP regime. Some aspects of the experiment are of general interest in the field of discharge lamps, such as a model for the heat balance of the Hg condensate under conductive, radiative, and evaporative cooling/heating, a short discussion of high-temperature vapor-pressure data for Hg, and an improved Hg equation of state for UHP conditions.

Hechtfischer, U.; Engelbrecht, B.; Carpaij, M.; Fischer, E.; Koerber, A. [Philips Research Laboratories, Weisshausstrasse 2, 52066 Aachen (Germany)

2009-09-01

434

Pressure Ratio to Thermal Environments  

NASA Technical Reports Server (NTRS)

A pressure ratio to thermal environments (PRatTlE.pl) program is a Perl language code that estimates heating at requested body point locations by scaling the heating at a reference location times a pressure ratio factor. The pressure ratio factor is the ratio of the local pressure at the reference point and the requested point from CFD (computational fluid dynamics) solutions. This innovation provides pressure ratio-based thermal environments in an automated and traceable method. Previously, the pressure ratio methodology was implemented via a Microsoft Excel spreadsheet and macro scripts. PRatTlE is able to calculate heating environments for 150 body points in less than two minutes. PRatTlE is coded in Perl programming language, is command-line-driven, and has been successfully executed on both the HP and Linux platforms. It supports multiple concurrent runs. PRatTlE contains error trapping and input file format verification, which allows clear visibility into the input data structure and intermediate calculations.

Lopez, Pedro; Wang, Winston

2012-01-01

435

Photogrammetric prediction of girdle pressure  

NASA Astrophysics Data System (ADS)

A new method is proposed for indirect prediction of skin pressure induced by a tight-fit girdle, using in situ photogrammetric measurements in a close range. The 3D information of the markings on girdles being worn by seven woman subjects was acquired by five photographs captured from different horizontal angles. After digitizing the markings on the photographs, the body curvature and fabric strain at eight specific positions were calculated. From the result of the ANOVA test with repeated measures, both the body curvature and fabric strain were significantly different among subjects. Based on the materials' force-strain curves obtained from the Instron tensile test, the corresponding girdle pressure P was predictable by the local strain ?, fabric tension per unit length T and body curvature K. The predicted pressure values were verified by experimental measurements using novel pliance-x pressure sensors. The root-mean-squared error was 3.57 mmHg while an error of 4 mmHg was inherent in the current pressure measuring system. The correlation coefficients r (0.935) and r2 (0.873) indicated a significant linear relationship between the predicted and experimental pressure values (p < 0.001).

Ng, Sun-pui; Yu, Winnie; Li, Yi

2009-01-01

436

What Is High Blood Pressure Medicine?  

MedlinePLUS

(continued) Lifestyle + Risk Reduction High Blood Pressure What should I know about taking medicine? • Your doctor may prescribe one or more drugs to ... What Is High Blood Pressure Medicine? Lifestyle + Risk Reduction High Blood Pressure ANSWERS by heart Take a ...

437

Automatic blood pressure measuring system (M092)  

NASA Technical Reports Server (NTRS)

The Blood Pressure Measuring System is described. It measures blood pressure by the noninvasive Korotkoff sound technique on a continual basis as physical stress is imposed during experiment M092, Lower Body Negative Pressure, and experiment M171, Metabolic Activity.

Nolte, R. W.

1977-01-01

438

46 CFR 169.249 - Pressure vessels.  

Code of Federal Regulations, 2013 CFR

...2013-10-01 2013-10-01 false Pressure vessels. 169.249 Section 169.249 Shipping COAST GUARD, DEPARTMENT OF HOMELAND...VESSELS Inspection and Certification Inspections § 169.249 Pressure vessels. Pressure vessels must...

2013-10-01

439

Avoid the Consequences of High Blood Pressure  

MedlinePLUS

... Tools & Resources Stroke More Avoid the Consequences of High Blood Pressure Infographic Updated:Jun 19,2014 View a downloadable version of this infographic High Blood Pressure • Home • About High Blood Pressure (HBP) • Why HBP ...

440

49 CFR 229.107 - Pressure gauge.  

Code of Federal Regulations, 2013 CFR

...STANDARDS Safety Requirements Steam Generators § 229.107 Pressure gauge. (a) Each steam generator shall have an illuminated steam gauge...allowed working pressure of the steam generator. (b) Each steam pressure gauge...

2013-10-01

441

Spray bottle apparatus with pressure multiplying pistons  

DOEpatents

The present invention comprises a spray bottle in which the pressure resulting from the gripping force applied by the user is amplified and this increased pressure used in generating a spray such as an aerosol or fluid stream. In its preferred embodiment, the invention includes a high pressure chamber and a corresponding piston which is operative for driving fluid out of this chamber at high pressure through a spray nozzle and a low pressure chamber and a corresponding piston which is acted upon the hydraulic pressure within the bottle resulting from the gripping force. The low pressure chamber and piston are of larger size than the high pressure chamber and piston. The pistons are rigidly connected so that the force created by the pressure acting on the piston in the low pressure chamber is transmitted to the piston in the high pressure chamber where it is applied over a more limited area thereby generating greater hydraulic pressure for use in forming the spray.

Moss, Owen R. (Kennewick, WA); Gordon, Norman R. (Kennewick, WA); DeFord, Henry S. (Kennewick, WA)

1990-01-01

442

Sensitivity study on high pressurizer pressure trip margin of UCN 3 and 4.  

National Technical Information Service (NTIS)

Sensitivity studies for variables which affect high pressurizer pressure trip margin are performed using LTCUCN computer code which is performance analysis code of UCN 3 and 4. As the results of sensitivity study, initial pressurizer pressure, SBCS quick ...

S. H. Sohn W. S. Jeong H. T. Seo J. T. Seo

1996-01-01

443

Behavior of Intraocular Pressure, Blood Pressure and Body Weight under Peak Physical Exertion.  

National Technical Information Service (NTIS)

Weight, blood pressure and intraocular pressure were measured in healthy young men prior to, and after a 50-km walk. Comparative tables show that on an average the weight and intraocular pressure decreases, while blood pressure increases. (Author)

R. Kern

1972-01-01

444

FEA of CMUTs Suitable for Wide Gas Pressure Range Applications  

PubMed Central

The ability of ultrasound transducers to operate over a wide and varying pressure range is essential in applications such as ultrasonic flow metering (UFM) of flare gas. We propose a new operational mode for capacitive micromachined ultrasonic transducers (CMUTs), in which the plate is in permanent contact with the bottom of the cavity, even at zero DC bias and 1 atm pressure. Finite element analysis (FEA) software was used to investigate the performance of these CMUTs within the pressure range of 1 to 20 atm. First, we performed a static analysis to determine the plate deflection and, thus, the gap height. Further, from the static analysis, we obtained the static and free capacitances for calculating the coupling efficiency, and a modal analysis identified possible design geometries for frequencies lower than ~ 300 kHz. Our calculations show that conventionally operated CMUTs have huge changes in static operational point at different pressures, while our proposed mode exhibits an acceptable frequency range (73 – 340 kHz) over 1 – 20 atm pressure and an improved coupling efficiency at lower dc bias voltages. A donut shape partial electrode further allows us to tune the coupling efficiency, which translates into a better performance, especially at the higher pressure range. FEA shows that our proposed operation mode is a promising solution for flare gas metering applications.

Ho, Min-Chieh; Kupnik, Mario; Khuri-Yakub, Butrus T.

2010-01-01

445

Optical pressure/density measuring means  

DOEpatents

An apparatus and method for rapidly and accurately determining the pressure of a fluid medium in either a static or dynamic state. The pressure is determined by making a measurement of the velocity of a light beam that is directed through the fluid medium along a pathway that enables an integrated pressure measurement to be made along the pathway, rather than making such a measurement only at a single point in the medium. A HeNe laser is configured to emit a beam of two frequencies separated by about 2 MHz. One of these beam frequencies is directed through the fluid medium and is reflected back through the medium to a non-linear diode detector. The other beam frequency is passed directly to a diode detector without traversing said medium. The diode detector is operated to determine the frequency shift or beat frequency between the two beam frequencies. Any variation in the frequency of said reflected beam that is caused by a change in its velocity as it is passed through the fluid medium causes a change in the beat frequency. This beat frequency change is then converted to an output signal value corresponding to the pressure of the medium. The measurement instrument apparatus is remotely positioned relative to the medium being measured, thus the apparatus is immune from electro-magnetic interference and can operate in conditions of high radiation, corrosion and extraordinarily high temperature.

Veligdan, James T. (Manorville, NY) [Manorville, NY

1995-05-09

446

Optical pressure/density measuring means  

DOEpatents

An apparatus and method are disclosed for rapidly and accurately determining the pressure of a fluid medium in either a static or dynamic state. The pressure is determined by making a measurement of the velocity of a light beam that is directed through the fluid medium along a pathway that enables an integrated pressure measurement to be made along the pathway, rather than making such a measurement only at a single point in the medium. A HeNe laser is configured to emit a beam of two frequencies separated by about 2 MHz. One of these beam frequencies is directed through the fluid medium and is reflected back through the medium to a non-linear diode detector. The other beam frequency is passed directly to a diode detector without traversing said medium. The diode detector is operated to determine the frequency shift or beat frequency between the two beam frequencies. Any variation in the frequency of said reflected beam that is caused by a change in its velocity as it is passed through the fluid medium causes a change in the beat frequency. This beat frequency change is then converted to an output signal value corresponding to the pressure of the medium. The measurement instrument apparatus is remotely positioned relative to the medium being measured, thus the apparatus is immune from electro-magnetic interference and can operate in conditions of high radiation, corrosion and extraordinarily high temperature. 4 figs.

Veligdan, J.T.

1995-05-09

447

Basic principles for measurement of intramuscular pressure  

NASA Technical Reports Server (NTRS)

We review historical and methodological approaches to measurements of intramuscular pressure (IMP) in humans. These techniques provide valuable measures of muscle tone and activity as well as diagnostic criteria for evaluation of exertional compartment syndrome. Although the wick and catheter techniques provide accurate measurements of IMP at rest, their value for exercise studies and diagnosis of exertional compartment syndrome is limited because of low frequency response and hydrostatic (static and inertial) pressure artifacts. Presently, most information on diagnosis of exertional compartment syndromes during dynamic exercise is available using the Myopress catheter. However, future research and clinical diagnosis using IMP can be optimized by the use of a miniature transducer-tipped catheter such as the Millar Mikro-tip.

Hargens, A. R.; Ballard, R. E.

1995-01-01

448

High-pressure cryogenic seals for pressure vessels  

NASA Technical Reports Server (NTRS)

Problems associated with maintaining high pressures at cryogenic temperatures in pressure vessels are investigated. The goals were to identify the appropriate materials and design for a seal intended for cryogenic applications at pressures up to 4,080 bars (60,000 psi), and to examine the factors affecting the seal performance. The method employed and the apparatus used in a series of experimental seal system tests, and the test results are described in detail. It is concluded that the common seal designs and extrusion seal-ring materials such as Teflon, tin, and lead are not suitable. However, new seal systems developed using indium seal rings, brass or 304 stainless steel anvil rings, and two 0-rings of silicone rubber or Kel-F did prove suitable.

Buggle, A. E.

1977-01-01

449

Blade Tip Pressure Measurements Using Pressure Sensitive Paint  

NASA Technical Reports Server (NTRS)

This paper discusses the application of pressure sensitive paint using laser-based excitation for measurement of the upper surface pressure distribution on the tips of rotor blades in hover and simulated forward flight. The testing was conducted in the Rotor Test Cell and the 14- by 22-ft Subsonic Tunnel at the NASA Langley Research Center on the General Rotor Model System (GRMS) test stand. The Mach-scaled rotor contained three chordwise rows of dynamic pressure transducers for comparison with PSP measurements. The rotor had an 11 ft 1 in. diameter, 5.45 in. main chord and a swept, tapered tip. Three thrust conditions were examined in hover, C(sub T) = 0.004, 0.006 and 0.008. In forward flight, an additional thrust condition, C(sub T) = 0.010 was also examined. All four thrust conditions in forward flight were conducted at an advance ratio of 0.35.

Wong, Oliver D.; Watkins, Anthony Neal; Goodman, Kyle Z.; Crafton, James; Forlines, Alan; Goss, Larry; Gregory, James W.; Juliano, Thomas J.

2012-01-01

450

Constant-Differential-Pressure Two-Fluid Accumulator  

NASA Technical Reports Server (NTRS)

A two-fluid accumulator has been designed, built, and demonstrated to provide an acceptably close approximation to constant differential static pressure between two fluids over the full ranges of (1) accumulator stroke, (2) rates of flow of the fluids, and (3) common static pressure applied to the fluids. Prior differential- pressure two-fluid accumulators are generally not capable of maintaining acceptably close approximations to constant differential pressures. The inadequacies of a typical prior differential-pressure two-fluid accumulator can be summarized as follows: The static differential pressure is governed by the intrinsic spring rate (essentially, the stiffness) of an accumulator tank. The spring rate can be tailored through selection of the tank-wall thickness, selection of the number and/or shape of accumulator convolutions, and/or selection of accumulator material(s). Reliance on the intrinsic spring rate of the tank results in three severe limitations: (1) The spring rate and the expulsion efficiency tend to be inversely proportional to each other: that is to say, as the stiffness (and thus the differential pressure) is increased, the range of motion of the accumulator is reduced. (2) As the applied common static pressure increases, the differential pressure tends to decrease. An additional disadvantage, which may or may not be considered limiting, depending on the specific application, is that an increase in stiffness entails an increase in weight. (3) The additional weight required by a low expulsion efficiency accumulator eliminates the advantage given to such gas storage systems. The high expulsion efficiency provided by this two-fluid accumulator allows for a lightweight, tightly packaged system, which can be used in conjunction with a fuel cell-based system.

Piecuch, Benjamin; Dalton, Luke T.

2010-01-01

451

Intraoral pressure patterns during swallowing.  

PubMed

Swallowing disturbances are common after neurological disease and oropharyngeal tumor resection. In this case the oral stage is often affected. So far the clinical evaluation of the oral phase is limited. Recently the role of pressure changes during oropharyngeal swallowing has been pointed out, but until now there are not enough data. Thereby 52 healthy adults aged between 20 and 45 years were examined using an oral shield (Silencos(®), Bredent, Senden, Germany) connected to a digital manometer (GDUSB 1000(®), Greisinger electronics, Regenstauf, Germany) able to record pressures in a range of 2,000 to -1,000 mbar at a frequency of 1 kHz. Three swallowing conditions were measured: an active bolus intake (ABI) of water, a passive bolus application of a water-bolus (PWA) and a passive application of a gel-bolus (PGA). We found negative pressures with a median value of -278.9 mbar during ABI, of -24.2 mbar during PWA and of -29.4 mbar during PGA. Significant differences in pressure amplitudes and the pressure pattern were observed depending on the kind of bolus application and its consistency. The used test presents a simple and easy to handle method to assess the oral phase of swallowing. PMID:23238701

Santander, Petra; Engelke, Wilfried; Olthoff, Arno; Völter, Christiane

2013-03-01

452

Variation in intravaginal pressure measurements.  

PubMed

The wide variation in intravaginal pressure measurements of the circumvaginal muscles (CVM) was studied in five subjects under well-controlled conditions. Previous research and clinical observations have indicated that fluctuations in the measurement of intravaginal pressure may be associated with time of day, day of testing, and existing stress factors. Subjects were assessed four times per day, on four consecutive days, for a total of 16 assessments. At each of the 16 conditions for a given subject, 10 CVM contractions lasting 12 seconds each were recorded and the variables, maximum pressure (MP10), peak maximum pressure (PMP), and abdominal pressure were analyzed. The within-subject variance was 15.5 (SD = 3.9); the between-subject variance was 132.4 (SD = 11.5). The effects of day, time, and stressor were analyzed by ANOVA specifically designed for variance estimates; no significant differences were found. The clinical observations that led to the study were not supported when systematically investigated. However, consistent data collection procedures appeared to reduce within-subject variance. PMID:1896326

Dougherty, M C; Bishop, K R; Mooney, R A; Gimotty, P A; Landy, L B

1991-01-01

453

Vapor pressures of new fluorocarbons  

SciTech Connect

The vapor pressures of four fluorocarbons have been measured at the following temperature ranges: R123 (2,2-dichloro-1,1,1-trifluoroethane), 273-457 K; R123a (1,2-dichloro-1,1,2-trifluoroethane), 303-458 K; R134a (1,1,1,2-tetrafluoroethane), 253-373 K; and R132b (1,2-dichloro-1,1-difluoroethane), 273-398 K. Determinations of the vapor pressure were carried out by a constant-volume apparatus with an uncertainty of less than 1.0%. The vapor pressures of R123 and R123a are very similar to those of R11 over the whole experimental temperature range, but the vapor pressures of R134a and R132b differ somewhat from those of R12 and R113, respectively, as the temperature increases. The numerical vapor pressure data can be fitted by an empirical equation using the Chebyshev polynomial with a mean deviation of less than 0.3%.

Kubota, H.; Yamashita, T.; Tanaka, Y.; Makita, T. (Kobe Univ. (Japan))

1989-05-01

454

Pressure dependence on the reaction propagation rate of PETN at high pressure  

SciTech Connect

The reaction propagation rate (RPR) of the sensitive high explosive pentaerythritol tetranitrate (PETN) was measured in a diamond anvil cell (DAC) over the pressure range of 2--20 GPa. The experimental technique used is the same as that previously reported. The RPR data shows that it burns one to two orders of magnitude faster in the DAC than 1,3,5,-triamino-2,4,6-trinitrobenzene (TATB) and nitromethane (CH{sub 3}NO{sub 2}) respectively. The PETN RPR curve did not show sample pressure-dependent behavior like that of nitromethane, but instead varied abruptly like the RPR curve of TATB. In order to interpret these changes, static-pressure DAC mid-IR FTIR spectra were taken of micro-pellets of PETN embedded in KBr. The relationship between changes in the spectra, the RPR curve, and published single crystal PETN wedge test data are discussed.

Foltz, M.F.

1993-04-01

455

High-pressure creep tests  

NASA Technical Reports Server (NTRS)

The automotive Stirling engine, presently being developed by the U.S. Department of Energy and NASA, uses high-pressure hydrogen as a working fluid; its long-term effects on the properties of alloys are relatively unknown. Hence, creep-rupture testing of wrought and cast high-temperature alloys in high-pressure hydrogen is an essential part of the research supporting the development of the Stirling cycle engine. Attention is given to the design, development, and operation of a 20 MPa hydrogen high-temperature multispecimen creep-rupture possessing high sensitivity. This pressure vessel allows for the simultaneous yet independent testing of six specimens. The results from one alloy, XF-818, are presented to illustrate how reported results are derived from the raw test data.

Bhattacharyya, S.; Lamoureux, J.; Hales, C.

1986-01-01

456

Zirconate pyrochlores under high pressure  

SciTech Connect

Ab initio total-energy calculations and x-ray diffraction measurements have been combined to study the phase stability of zirconate pyrochlores (A2Zr2O7; A=La, Nd and Sm) under pressures up to 50 GPa. Phase transformations to the defect-cotunnite structure are theoretically predicted at pressures of 22, 20 and 18 GPa, in excellent agreement with the experimentally determined values of 21, 22 and 18 GPa for La2Zr2O7, Nd2Zr2O7 and Sm2Zr2O7, respectively. Analysis of the elastic properties indicate that elastic anisotropy may be one of the driving forces for the pressure-induced cubic-to-noncubic phase transformation.

Xiao, Haiyan [Pacific Northwest National Laboratory (PNNL); Zhang, Fuxiang [University of Michigan; Gao, Fei [Pacific Northwest National Laboratory (PNNL); Ewing, Rodney C. [University of Michigan; Weber, William J [ORNL

2010-01-01

457

Zirconate pyrochlores under high pressure  

SciTech Connect

Ab initio total-energy calculations and x-ray diffraction measurements have been combined to study the phase stability of zirconate pyrochlores (A2Zr2O7; A=La, Nd and Sm) under pressures up to 50 GPa. Phase transformations to the defect-cotunnite structure are theoretically predicted at pressures of 22, 20 and 18 GPa, in excellent agreement with the experimentally determined values of 21, 22 and 18 GPa for La2Zr2O7, Nd2Zr2O7 and Sm2Zr2O7, respectively. Analysis of the elastic properties indicates that elastic anisotropy may be one of the driving forces for the pressure-induced cubic-to-noncubic phase transformation.

Xiao, Haiyan Y.; Zhang, F. X.; Gao, Fei; Lang, Maik; Ewing, Rodney C.; Weber, William J.

2010-07-12

458

Level indicator for pressure vessels  

DOEpatents

A liquid-level monitor for tracking the level of a coal slurry in a high-pressure vessel including a toroidal-shaped float with magnetically permeable bands thereon disposed within the vessel, two pairs of magnetic-field generators and detectors disposed outside the vessel adjacent the top and bottom thereof and magnetically coupled to the magnetically permeable bands on the float, and signal-processing circuitry for combining signals from the top and bottom detectors for generating a monotonically increasing analog control signal which is a function of liquid level. The control signal may be utilized to operate high-pressure control valves associated with processes in which the high-pressure vessel is used.

Not Available

1982-04-28

459

High pressure liquid level monitor  

DOEpatents

A liquid level monitor for tracking the level of a coal slurry in a high-pressure vessel including a toroidal-shaped float with magnetically permeable bands thereon disposed within the vessel, two pairs of magnetic field generators and detectors disposed outside the vessel adjacent the top and bottom thereof and magnetically coupled to the magnetically permeable bands on the float, and signal processing circuitry for combining signals from the top and bottom detectors for generating a monotonically increasing analog control signal which is a function of liquid level. The control signal may be utilized to operate high-pressure control valves associated with processes in which the high-pressure vessel is used.

Bean, Vern E. (Frederick, MD); Long, Frederick G. (Ijamsville, MD)

1984-01-01

460

Optical pressure sealing coupling apparatus  

NASA Technical Reports Server (NTRS)

An apparatus is presented for optically coupling and pressure sealing sections of an instrument probe, one of the section being at a high pressure cryogenic environment and the other section being at ambient pressure. The apparatus includes a housing having a passageway within which elements are mounted for precisely locating a rigid optical fiber coupler and the probe sections so as to optically connect and maintain the ends of the probe sections together to permit signals to pass in both directions through the joint in two or more discrete channels. An adjustable positioning member acts to connect the external section of the probe to the housing in axial and rotation alignment with the interior section.

Irvin, Timothy B. (inventor); French, Richard E. (inventor)

1989-01-01

461

Welding wire pressure sensor assembly  

NASA Technical Reports Server (NTRS)

The present invention relates to a device which is used to monitor the position of a filler wire relative to a base material being welded as the filler wire is added to a welding pool. The device is applicable to automated welding systems wherein nonconsumable electrode arc welding processes are utilized in conjunction with a filler wire which is added to a weld pool created by the elect