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1

An Improved Static Pressure Probe.  

National Technical Information Service (NTIS)

An improved design for shortened static pressure probes for supersonic velocities, is given. The probe has a smaller length than conventional static probes with the same diameter and requires no compensation for yaw angles of up to 10 deg.

S. Z. Pinckney

1974-01-01

2

14 CFR 23.1325 - Static pressure system.  

Code of Federal Regulations, 2010 CFR

...Evacuate the static pressure system to a pressure differential of approximately...above the aircraft elevation at the time of the...Evacuate the static pressure system until a pressure...system and true ambient atmospheric static pressure...

2009-01-01

3

14 CFR 23.1325 - Static pressure system.  

Code of Federal Regulations, 2013 CFR

...Evacuate the static pressure system to a pressure differential of approximately...above the aircraft elevation at the time of the...Evacuate the static pressure system until a pressure...system and true ambient atmospheric static pressure...

2013-01-01

4

14 CFR 23.1325 - Static pressure system.  

Code of Federal Regulations, 2010 CFR

...Evacuate the static pressure system to a pressure differential of approximately...above the aircraft elevation at the time of the...Evacuate the static pressure system until a pressure...system and true ambient atmospheric static pressure...

2010-01-01

5

14 CFR 25.1325 - Static pressure systems.  

Code of Federal Regulations, 2013 CFR

...and that the correlation between air pressure in the static pressure system and true ambient atmospheric static pressure is not changed when the airplane...1,000 feet above the airplane elevation at the time of the test....

2013-01-01

6

14 CFR 25.1325 - Static pressure systems.  

Code of Federal Regulations, 2010 CFR

...and that the correlation between air pressure in the static pressure system and true ambient atmospheric static pressure is not changed when the airplane...1,000 feet above the airplane elevation at the time of the test....

2010-01-01

7

14 CFR 25.1325 - Static pressure systems.  

Code of Federal Regulations, 2010 CFR

...and that the correlation between air pressure in the static pressure system and true ambient atmospheric static pressure is not changed when the airplane...1,000 feet above the airplane elevation at the time of the test....

2009-01-01

8

14 CFR 27.1325 - Static pressure systems.  

Code of Federal Regulations, 2013 CFR

...other is blocked off; and (2) Both sources cannot be blocked off simultaneously...calibration, when either static pressure source is selected is not changed by the other static pressure source being open or blocked. (Secs....

2013-01-01

9

14 CFR 29.1325 - Static pressure and pressure altimeter systems.  

Code of Federal Regulations, 2013 CFR

...is blocked off; and (2) Both sources cannot be blocked off simultaneously...calibration, when either static pressure source is selected, is not changed by the other static pressure source being open or blocked. (Secs....

2013-01-01

10

An accuracy statement for a facility used to calibrate static pressure transducers and differential pressure transducers at high base pressure  

Microsoft Academic Search

A facility was developed to calibrate pressure transducers that are used in a gas mass flow facility. Both static and differential pressure transducers can be calibrated. An air dead weight tester is the standard for static transducers in the range from 3.8 to 4.5 MPa. An air dead weight tester is also the standard for the differential pressure transducers in

C. F. Sindt; J. F. Labrecque

1982-01-01

11

An Accuracy Statement for a Facility Used to Calibrate Static Pressure Transducers and Differential Pressure Transducers at High Base Pressure.  

National Technical Information Service (NTIS)

A facility has been developed to calibrate pressure transducers that are used in the NBS Gas Mass Flow Facility. Both static and differential pressure transducers can be calibrated. An air dead weight tester is the standard for static transducers in the r...

C. F. Sindt J. F. LaBrecque

1982-01-01

12

Intrinsic PEEP on static pressure-volume curves  

Microsoft Academic Search

The static pressure volume (PV) curve of the total respiratory system is a well established method to assess pulmonary mechanics during respiratory failure. We have tested the impact of auto-PEEP on the PV curve determination in 16 COPD patients. An isovolumic pressure increment (IPI) was found at the beginning of the curve and a close correlation between IPI and auto-PEEP

R. Fernfindez; J. Mancebo; Ll. Blanch; S. Benito; N. Calaf; A. Net

1990-01-01

13

Pressure Measurements in Jets Diffusion using a Developed Hot-Wire Static Pressure Sensor  

NASA Astrophysics Data System (ADS)

The aim of this experimental study is to investigate the diffusion of jets, with particular attention focused on the relationship between the static pressure and the stream wise mean velocity on the development of a two-dimensional air jet. A jet with three injection velocities (11.7, 23.3 and 35.0 m/s) was generated in a two-dimensional wind tunnel. The velocity distributions were measured by an X-type hot-wire anemometer. The static pressure distributions were measured by a static pressure probe developed in our laboratory, which incorporates a hot-wire anemometer. The probe is designed to be able to measure the mean static pressure and pressure fluctuation simultaneously. The sensitivity is 92.3 mV/Pa. The frequency response is flat from 16 Hz to 2.5 kHz. As a result of the experiment, it was found that negative static pressure exists in the turbulent shear layer. It is considered that the entrainment process from the negative static pressure by the vortex structure motion of the turbulent shear layer.

Kimura, Motoaki; Miyagi, Norimasa

14

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

15

Static filling pressure in patients during induced ventricular fibrillation.  

PubMed

The static pressure resulting after the cessation of flow is thought to reflect the filling of the cardiovascular system. In the past, static filling pressures or mean circulatory filling pressures have only been reported in experimental animals and in human corpses, respectively. We investigated arterial and central venous pressures in supine, anesthetized humans with longer fibrillation/defibrillation sequences (FDSs) during cardioverter/defibrillator implantation. In 82 patients, the average number of FDSs was 4 +/- 2 (mean +/- SD), and their duration was 13 +/- 2 s. In a total of 323 FDSs, arterial blood pressure decreased with a time constant of 2.9 +/- 1.0 s from 77.5 +/- 34.4 to 24.2 +/- 5.3 mmHg. Central venous pressure increased with a time constant of 3.6 +/- 1.3 s from 7.5 +/- 5.2 to 11.0 +/- 5.4 mmHg (36 points, 141 FDS). The average arteriocentral venous blood pressure difference remained at 13.2 +/- 6.2 mmHg. Although it slowly decreased, the pressure difference persisted even with FDSs lasting 20 s. Lack of true equilibrium pressure could possibly be due to a waterfall mechanism. However, waterfalls were identified neither between the left ventricle and large arteries nor at the level of the diaphragm in supine patients. We therefore suggest that static filling pressures/mean circulatory pressures can only be directly assessed if the time after termination of cardiac pumping is adequate, i.e., >20 s. For humans, such times are beyond ethical options. PMID:12907428

Schipke, J D; Heusch, G; Sanii, A P; Gams, E; Winter, J

2003-08-07

16

Blood pressure response to low level static contractions  

Microsoft Academic Search

Summary  The present study re-examines the 15% MVC concept, i.e. the existence of a circulatory steady-state in low intensity static contractions below 15% of maximal voluntary contraction (MVC). Mean arterial blood pressure was studied during static endurance contractions of the elbow flexor and extensor muscles at forces corresponding to 10% and 40% MVC. Mean value for endurance time at 10% MVC

Nils Fallentin I; Kurt Jørgensen

1992-01-01

17

Pressure  

NSDL National Science Digital Library

This lab is not inquiry-based because the teacher must explain how to calculate pressure before doing the activity, but the lab gives students a great concept of what PSI means. They usually have no idea if 10 PSI is a lot or a little. They also don't und

Horton, Michael

2009-05-30

18

Radio jet refraction in galactic atmospheres with static pressure gradients  

SciTech Connect

A theory of double radio sources which has 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 the method used by Begelman, Rees, and Blandford to calculate a ram-pressure model for twin radio trails (C morphology). It may also be described as a continuous-jet version of the buoyancy model proposed by Gull and Northover.

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

1981-10-01

19

Strength measurement using Diamond Anvil Cell under Static pressure  

NASA Astrophysics Data System (ADS)

The pressure-dependence of the quasi-static yield strength of polycrystalline samples has been measured in the diamond anvil cell at high pressure (up to 80 GPa) and room temperature using an implementation of a non-hydrostatic technique used by Meade and Jeanloz [J. Geophys. Res. 93, 3261 (1988)]. Vanadium and Tantalum-Tungsten alloys are studied, including vanadium in the pressure range of a recently reported high-pressure phase. We introduce the use of in situ synchrotron X-ray determination of the sample thickness and pressure. In addition we use a step-wise analysis approach to obtain the pressure-dependent strength under the Tresca yield criterion. The results are compared with those by the previous technique of Meade and Jeanloz. This work performed under the auspices of the US DOE by LLNL under Contract DE-AC52-07NA27344. HPCAT use is supported by DOE-BES, DOENNSA, NSF, and the W.M. Keck Foundation. APS is supported by DOE-BES, under Contract No. DE-AC02-06CH11357.

Klepeis, Jae-Hyun; Cynn, Hyunchae; Evans, William; Rudd, Robert; Yang, Lin; Hsiung, Luke; Park, Changyong; Shebanova, Olga; Kenney-Benson, Curtis; Sinogeikin, Stanislav

2011-06-01

20

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

21

Blood pressure response to low level static contractions.  

PubMed

The present study re-examines the 15% MVC concept, i.e. the existence of a circulatory steady-state in low intensity static contractions below 15% of maximal voluntary contraction (MVC). Mean arterial blood pressure was studied during static endurance contractions of the elbow flexor and extensor muscles at forces corresponding to 10% and 40% MVC. Mean value for endurance time at 10% MVC was significantly longer for flexion [111.3 (SD 56.1) min] than for extension [18.1 (SD 7.5) min; n = 7]. At 40% MVC the difference in mean endurance time disappeared [2.3 (SD 0.7) min for elbow flexion and 2.3 (SD 0.7) min for elbow extension]. Mean arterial blood pressure exhibited a continuous and progressive increase during the 10% MVC contractions indicating that the 15% MVC concept would not appear to be valid. The terminal blood pressure value recorded at the point of exhaustion in the 10% MVC elbow extension experiment was identical to the peak pressure attained in the 40% MVC contraction. For the elbow flexors the terminal pressor response was slightly but significantly lower at 10% MVC [122.3 (SD 10.1) mmHg, 16.3 (SD 1.4) kPa] in comparison with 40% MVC [130.4 (SD 7.4) mmHg, 17.4 (SD 1.0) kPa]. When the circulation to the muscles was arrested just prior to the cessation of the contraction, blood pressure only partly recovered and remained elevated for as long as the occlusion persisted, indicating the level of pressure-raising muscle chemoreflexes.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:1612087

Fallentin, N; Jørgensen, K

1992-01-01

22

Electrical conductivity measurement of iron at high static pressure  

NASA Astrophysics Data System (ADS)

The knowledge of the thermal conductivity of the core constrains the heat flow and the amount of radiogenic elements in the core [1]. The electrical conductivity of iron has been measured by shock compression experiments. The thermal conductivity can be then calculated using the Wiedemann-Franz law. Stacey and Loper [2] estimated the thermal conductivity of outer core liquid and suggested the absence of radiogenic heat source. However, no conductivity measurement has been carried out under core pressures by static experiments. In this study, we have conducted the electrical conductivity measurements of pure iron under high static pressure at room temperature in a diamond-anvil cell. The sample resistance was obtained by the four-terminal method. The results demonstrated that the conductivity increased with increasing pressure and dropped at ~15 GPa across phase transition from bcc to hcp structure. It then increased again with pressure up to 65 GPa. The electrical conductivity was determined to be about 1E7 S/m at 65 GPa. We estimated the electrical conductivity of iron under the CMB pressure and temperature condition to be ~ 1E6 S/m, which is comparable to the previous estimate by Stacey and Anderson [3]. The details of the experiments will be reported at the presentation. [1] Stevenson, D.J., 2003. Planetary magnetic fields. Earth Plan. Sci. Lett. 208, 1-11. [2] Stacey, F.D., Loper, D.E., 2007. Physics of the Earth Plan. Int. 161, 13-18. [3] Stacey, F.D., Anderson, O.L., 2001. Electrical and thermal conductivities of Fe-Ni-Si alloy under core conditions. Phys. Earth Planet. Inter. 124, 153-162.

Gomi, H.; Ohta, K.; Hirose, K.

2010-12-01

23

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...

2013-07-01

24

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

25

On Static Pressure Fluctuation between Sirocco Fan Blades in a Car Air-Conditioning System  

Microsoft Academic Search

In this study, special attention is directed to static pressure fluctuation in a sirocco fan for a car air-conditioning system, because it is expected that there is a close connection between the fluid noise and the pressure fluctuation. The final purpose of this study is to clarify the relationship between the static pressure fluctuation between fan blades and the sound

Yasuhiko Sakai; Takaaki Kato; Yuu Moriguchi; Masaharu Sakai; Kouji Ito; Yasushi Mitsuishi; Kouji Nagata; Takashi Kubo

2008-01-01

26

Maximum static inspiratory and expiratory pressures with different lung volumes  

PubMed Central

Background Maximum pressures developed by the respiratory muscles can indicate the health of the respiratory system, help to determine maximum respiratory flow rates, and contribute to respiratory power development. Past measurements of maximum pressures have been found to be inadequate for inclusion in some exercise models involving respiration. Methods Maximum inspiratory and expiratory airway pressures were measured over a range of lung volumes in 29 female and 19 male adults. A commercial bell spirometry system was programmed to occlude airflow at nine target lung volumes ranging from 10% to 90% of vital capacity. Results In women, maximum expiratory pressure increased with volume from 39 to 61 cmH2O and maximum inspiratory pressure decreased with volume from 66 to 28 cmH2O. In men, maximum expiratory pressure increased with volume from 63 to 97 cmH2O and maximum inspiratory pressure decreased with volume from 97 to 39 cmH2O. Equations describing pressures for both sexes are: Pe/Pmax = 0.1426 Ln( %VC) + 0.3402 R2 = 0.95 Pi/Pmax = 0.234 Ln(100 - %VC) - 0.0828 R2 = 0.96 Conclusion These results were found to be consistent with values and trends obtained by other authors. Regression equations may be suitable for respiratory mechanics models.

Lausted, Christopher G; Johnson, Arthur T; Scott, William H; Johnson, Monique M; Coyne, Karen M; Coursey, Derya C

2006-01-01

27

Prediction of Severe Eye Injuries in Automobile Accidents: Static and Dynamic Rupture Pressure of the Eye  

PubMed Central

The purpose of this paper is to determine the static and dynamic rupture pressures of 20 human and 20 porcine eyes. This study found the static test results show an average rupture pressure for porcine eyes of 1.00 ± 0.18 MPa while the average rupture pressure for human eyes was 0.36 ± 0.20 MPa. For dynamic loading, the average porcine rupture pressure was 1.64 ± 0.32 MPa, and the average rupture pressure for human eyes was 0.91 ± 0.29 MPa. Significant differences are found between average rupture pressures from all four groups of tests (p = 0.01). A risk function has been developed and predicts a 50% risk of globe rupture at 1.02 MPa, 1.66 MPa, 0.35 MPa, and 0.90 MPa internal pressure for porcine static, porcine dynamic, human static, and human dynamic loading conditions, respectively.

Kennedy, Eric A.; Voorhies, Katherine D.; Herring, Ian P.; Rath, Amber L.; Duma, Stefan M.

2004-01-01

28

Maximal respiratory static pressures in patients with different stages of COPD severity  

Microsoft Academic Search

BACKGROUND: In this study, we analyzed maximal inspiratory pressure (MIP) and maximal expiratory pressure (MEP) values in a stable COPD population compared with normal subjects. We evaluated the possible correlation between functional maximal respiratory static pressures and functional and anthropometric parameters at different stages of COPD. Furthermore, we considered the possible correlation between airway obstruction and MIP and MEP values.

Claudio Terzano; Daniela Ceccarelli; Vittoria Conti; Elda Graziani; Alberto Ricci; Angelo Petroianni

2008-01-01

29

Effects of Constant Static Pressure on the Biological Properties of Porcine Aortic Valve Leaflets  

Microsoft Academic Search

An understanding of how mechanical forces impact cells within valve leaflets would greatly benefit the development of a tissue-engineered heart valve. In this study, the effect of constant ambient pressure on the biological properties of heart valve leaflets was evaluated using a custom-designed pressure system. Native porcine aortic valve leaflets were exposed to static pressures of 100, 140, or 170

Yun Xing; Zhaoming He; James N. Warnock; Stephen L. Hilbert; Ajit. P. Yoganathan

2004-01-01

30

Static foot pressure image analysis for variation in Men and Women while standing  

Microsoft Academic Search

The purpose of this study was to analyze static foot pressure image to obtain the plantar pressure distribution variation between Men and Women using image processing in frequency domain. Methods: We examined 38 feet of 19 healthy subjects (12 Men and 7 Women) aged between twenty to forty five years was recruited for our study. Foot pressure distribution patterns while

R. Periyasamy; S. Anand; A. Mishra; A. C. Ammini

2010-01-01

31

DEFLAGRATION RATES OF SECONDARY EXPLOSIVES UNDER STATIC MPA - GPA PRESSURE  

SciTech Connect

We provide measurements of the chemical reaction propagation rate (RPR) as a function of pressure using diamond anvil cell (DAC) and strand burner technologies. Materials investigated include HMX and RDX crystalline powders, LX-04 (85% HMX and 15% Viton A), and Composition B (63% RDX, 36% TNT, 1% wax). The anomalous correspondence between crystal structure, including in some instances isostructural phase transitions, on pressure dependent RPRs of HMX and RDX are correlated to confocal micro-Raman spectroscopic results. The contrast between DAC GPa and strand burner MPa regime measurements yield insight into explosive material burn phenomena. Here we highlight pressure dependent physicochemical mechanisms that appear to affect the deflagration rate of precompressed energetic materials.

Zaug, J; Young, C; Long, G; Maienschein, J; Glascoe, E; Hansen, D; Wardell, J; Black, C; Sykora, G

2009-07-30

32

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

33

Dependence of the Maximum Static Pressure in the Inner Magnetosphere on the Solar Wind Dynamic Pressure and Different Coupling Functions  

NASA Astrophysics Data System (ADS)

Knowledge about distribution of plasma pressure is crucial for the evaluation of the stability of any plasma configuration. Nevertheless, this distribution should be affected by the solar wind-magnetosphere interaction, generally expressed as a series of coupling functions of Dungey, Akasofu, Newell, among others, as well as different characteristics of the solar wind like velocity, interplanetary magnetic field and dynamic pressure. In this study we used the precipitating particles flux data obtained by Aureol-3 satellite to reconstruct the radial plasma pressure profiles in the night-side inner magnetosphere with high space and time resolution. The instantaneous radial profiles of plasma pressure have been obtained using the THEMIS mission satellites. The dynamics of these profiles has been compared with the main parameters of the solar wind, inferred from the NSSDC date base. In particular, it was found that the maximum value of static pressure in the night-side inner magnetosphere correlates with the value of dynamic pressure of the solar wind. The position of the maximum is also affected by the solar wind dynamic pressure, being closer to the Earth in case of high dynamic pressure. The fact that the inner pressure in the magnetosphere and the relation with the dynamic pressure of the solar wind is important for understanding the dynamics of geomagnetic substorms and storms. Finally we compare these results with the analysis of THEMIS data.

Gallardo-Lacourt, B. I.; Stepanova, M. V.; Antonova, E. E.

2009-12-01

34

The problem of static pressure measurement in turbomachinery annuli using traversable instrumentation  

NASA Astrophysics Data System (ADS)

Traverse probes are used in a component rig and engine testing to measure a range of aerodynamic quantities. Of these quantities, static pressure is the least accurately indicated towards the wall of introduction. Three particularly problematic areas in the measurement of static pressure using specifically the wedge type traverse probe are explained, the discussion drawing on the findings of several researches in addition to 'in house' experience. In view of the importance of an accurate knowledge of the static pressure field in determining turbomachine performance and efficiency levels, an experimental and theoretical study was planned. With the ultimate goal of understanding the root causes of the static pressure measurement problem, details of this study are presented, a study which it is hoped will lead to an elimination of this fundamental problem, either through reviewed calibration procedures, or through new probe designs.

Smout, P. D.

1990-11-01

35

Energy efficient high static pressure fluid fuel burner  

SciTech Connect

A gun-type fluid fuel burner having a blast tube with a fuel dispensing nozzle therein includes a blower housing having a scroll side wall and opposite end walls. The housing side wall has an upwardly facing air discharge opening therein which communicates with the blast tube, and one of the end walls has an air inlet opening therein. A squirrel cage blower wheel having a diameter more than twice its width is mounted for rotation in the housing and is directly driven by a two pole single phase alternating current motor mounted on one of the housing end walls, the blower drawing air through the input opening and discharging the air under pressure through the discharge opening. A damper plate is mounted on the housing for movement between an open position and a position closing the discharge opening, the damper being moved to its open position in response to air pressure from the blower and returning to its closed position under the influence of biasing force.

Kaplan, R.A.; Wellman, J.E.

1983-06-14

36

Hot-film static-pressure probe for surveying flow fields  

NASA Astrophysics Data System (ADS)

A static pressure probe employing hot-film sensors has been developed for the rapid measurement of the static pressure fields surrounding analytic shapes in hypersonic flows. The hot-film probe is a modification of the standard static pressure probe, consisting of a front hot-film sensor operated as a resistance thermometer, a rear sensor operated at an overheat ratio of 1.5 to 1.8 and a small sonic orifice installed inside the tubing of a conventional device. The probe has been calibrated in helium and air over a range of temperatures and pressures in a bell jar apparatus, with a repeatability of the data to within + or - 0.015 mm Hg. Comparative tests of the hot-film and conventional static pressure probes in a hypersonic helium wind tunnel at Mach 20 and various Reynolds numbers have indicated the settling time of the hot-film probe to be on the order of milliseconds, as compared with 30 sec for the conventional probe. The pressures measured by the two probes were found to be within 10% of each other. Although the hot-film probe makes flow-field static pressure surveys more practical in blowdown hypersonic wind tunnels, viscous and flow angle effects still must be assessed under the conditions of use.

Ashby, G. C., Jr.; Weinstein, L. M.

1981-04-01

37

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

38

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 [Los Alamos National Laboratory, Los Alamos, NM 87545 (United States)

2007-12-12

39

Helium at elevated pressures: Quantum liquid with non-static shear rigidity  

NASA Astrophysics Data System (ADS)

The properties of liquid helium have always been a fascinating subject to scientists. The phonon theory of liquids, taking into account liquid non-static shear rigidity, is employed here for studying internal energy and heat capacity of compressed liquid 4He. We demonstrate the good agreement of calculated and experimental heat capacity of liquid helium at elevated pressures and supercritical temperatures. Unexpectedly, helium remains a quantum liquid at elevated pressures for a wide range of temperature supporting both longitudinal and transverse-like phonon excitations. We have found that in the very wide pressure range of 5 MPa-500 MPa, liquid helium near melting temperature is both solid-like and quantum.

Bolmatov, D.; Brazhkin, V. V.; Trachenko, K.

2013-03-01

40

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

41

Pressure and Sample Size Dependences of Static Friction Coefficient and Precursor Slips in Sheared Elastic Object  

NASA Astrophysics Data System (ADS)

It is well known that Amontons' law of friction holds well in various systems. The law states that the static friction coefficient does not depend on the pressure and system length. We showed, however, that the static friction constant in sheared elastic block decreases with the applied pressure and the system length by both of finite element method and analytic calculation. The elastic block is subject to the friction force obeying Amontons' law locally and to dissipation proportional to the instantaneous strain rate (arXiv:1202.1716v2). Here we extend our previous analysis to the elastic block subject to the local friction force obeying the rate and state dependent friction law and to the dissipation depending on the history of the strain rate. Is is shown that the static friction coefficient decreases with the applied pressure and system length generally. We also show that three kinds of precursor slip appear before the onset of bulk sliding, the adiabatic and bounded and leading rapid precursors. These precursors make the static friction coefficient decrease with the pressure and the system length. The relation with experiments is also discussed.

Matsukawa, Hiroshi; Otsuki, Michio

2013-03-01

42

Effects of microgravity on interstitial muscle receptors affecting heart rate and blood pressure during static exercise  

Microsoft Academic Search

Afferent nerve fibers from receptors situated in the interstitium of skeletal muscles can induce cardiovascular reflexes. It has been shown that these interstitial muscle receptors are also sensitive to the local state of hydration: increased heart rates and blood pressure values were seen during dynamic and static exercise after local dehydration on earth. Since weightlessness leads to a persisting fluid

D. Essfeld; K. Baum; U. Hoffmann; J. Stegemann

1993-01-01

43

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

44

Static lung compliance and body pressures in Tupinambis merianae with and without post-hepatic septum  

Microsoft Academic Search

The surgical removal of the post-hepatic septum (PHS) in the tegu lizard, Tupinambis merianae , significantly reduces resting lung volume (VLr) and maximal lung volume (VLm) when compared with tegus with intact PHS. Standardised for body mass (MB), static lung compliance was significantly less in tegus without PHS. Pleural and abdominal pressures followed, like ventilation, a biphasic pattern. In general,

Wilfried Klein; Augusto S. Abe; Steven F. Perry

2003-01-01

45

Aerosols generated by releases of pressurized powders and solutions in static air  

Microsoft Academic Search

Safety assessments and environmental impact statements for nuclear fuel cycle facilities require an estimate of potential airborne releases caused by accidents. Aerosols generated by accidents are being investigated by Pacific Northwest Laboratory to develop the source terms for these releases. An upper boundary accidental release event would be a pressurized release of powder or liquid in static air. Experiments were

Sutter

1983-01-01

46

Maximum Static Respiratory Pressures in Healthy Elderly Men and Women: Issues of Reproducibility and Interpretation  

Microsoft Academic Search

Background: Respiratory muscle strength is assessed using the static pressure generated at the mouth during a maximal inspiratory or expiratory effort [PImax and PEmax, respectively (MSRPs)]. Interpretation of MSRPs relies upon comparison with ‘normal’ values, but MSRPs show very weak associations with predictors such as physical characteristics. The influence of habitual physical activity upon MSRPs remains undefined. Objectives: We examined

A. K. McConnell; A. J. Copestake

1999-01-01

47

Bounds on the interior geometry and pressure profile of static fluid spheres  

NASA Astrophysics Data System (ADS)

It is a famous result of relativistic stellar structure that (under mild technical conditions) a static fluid sphere satisfies the Buchdahl Bondi bound 2M/R < 8/9; the surprise here being that the bound is not 2M/R < 1. In this paper, we provide further generalizations of this bound by placing a number of constraints on the interior geometry (the metric components), on the local acceleration due to gravity, on various combinations of the internal density and pressure profiles and on the internal compactness 2m(r)/r of static fluid spheres. We do this by adapting the standard tool of comparing the generic fluid sphere with a Schwarzschild interior geometry of the same mass and radius—in particular, we obtain several results for the pressure profile (not merely the central pressure) that are considerably more subtle than might first be expected.

Martin, Damien; Visser, Matt

2003-08-01

48

On the Concordance of Static High Pressure Phase Transformation Data on Minerals With Shock Wave Data  

NASA Astrophysics Data System (ADS)

About 50 years ago, shock wave researchers were confounded by the apparent rapidity of shock-induced phase transformations and invoked special mechanisms as an explanation. Some workers speculatively interpret shock wave data as indicative of very rapid reconstructive phase transformations of minerals at modest temperatures. The belief that kinetic effects are negligible has justified the use of microsecond duration shock recovery experiments to interpret much longer duration shock effects in terrestrial impact craters and in meteorites. Here we summarize the extensive evidence that phase transformations under shock compression are governed by the same kinetics as phase transitions under static compression. Hugoniot measurements on quartz and feldspars have been interpreted as indicating phase transitions to dense phases at pressures near 35 GPa. Release adiabat measurements imply that these phases persist on release of pressure down to about 7 GPa, below which there is expansion to a final density appropriate to a glass. Microsecond-duration shock recovery experiments support this interpretation; a low density amorphous phase (diaplectic glass) is recovered. A similar effect is observed in static compression experiments conducted at room temperature at a lower pressure, 12-15 GPa. The pressure difference is a kinetic effect; the transition requires higher shock pressures (implying higher shock temperatures) to run to completion on a microsecond time scale. Direct evidence for kinetic effects on the tectosilicate transformation is found in studies of naturally shocked meteorites that contain melt veins. When the melt veins solidify under pressure, the resultant mineralogy together with vein cooling calculations constrains the shock pressure-time history. In some samples, in which the shock pressure is constrained by vein mineralogy to a range of 17-25 Gpa, one may observe the presence of diaplectic glass in only near-vein regions heated by conduction from the vein. In other samples, constrained to the same pressure range, long-duration (> 0.1 s) shock pressures are inferred from constant high-pressure mineralogy across wide (>1mm) veins and diaplectic glass is found throughout the meteorite. Evidence for kinetic effects may also be inferred from studies of samples from large impact craters. Pressure estimates based on shock recovery experiments imply post-shock temperatures that are too high for the survival of metastable high-pressure phases, such as stishovite, present in the samples. Release adiabat measurements on quartz also account for the presence of coesite in association with stishovite and diaplectic glass. Release wave velocitie slow below about 7 GPa, providing a relatively long period for the growth of coesite in its stability field from shock heated silica. Studies of high-pressure phases of olivine and pyroxene in meteorites are also concordant with both static high pressure data and inferences from Hugoniot and release measurements. These phases are not found in microsecond duration shock recovery experiments. Finally experiments on the shock synthesis of diamond are in complete accord with evidence for shock synthesized diamond in large impact craters and with static high pressure data on the direct uncatalyzed transition of graphite to diamond.

de Carli, P. S.; El Goresy, A.; Xie, Z.; Sharp, T. G.

2006-12-01

49

Thermal Pressurization During the Transition From Quasi-Static Nucleation to Dynamic Rupture  

NASA Astrophysics Data System (ADS)

Shear heating-induced thermal pressurization has long been thought to be a significant weakening mechanism during earthquake rupture. Recent work has shown that, in some cases, thermal pressurization may become the dominant weakening mechanism during the quasi-static nucleation phase of an earthquake, well before the onset of seismic radiation. The importance of thermal pressurization is controlled by the fault zone's frictional and thermal/pore fluid transport properties. Numerical simulations of ``aging law'' rate/state-dependent friction coupled to shear heating and heat/fluid transport have shown that thermal pressurization dominates frictional weakening at slip speeds greater than 0.02 to 2 mm/s, depending on hydraulic diffusivity [Schmitt & others, JGR, submitted]. Understanding the role of thermal pressurization at the end of the nucleation phase is important since it sets the stage for the ensuing dynamic rupture. To that end, we investigate the effect of shear heating-induced thermal pressurization as a fault transitions from quasi-static to dynamic rupture. As in our prior studies, we use a quasi-static code to model fault slip from well below-steady-state to the early stages of nucleation. Unlike prior studies, however, we include a finite-width zone of shear (~100 microns) in the simulations, motivated by geologic observations of shear zones believed to have hosted earthquakes [Chester & Chester, Tectonophysics, 1998]. We find that shear heating forms a pore pressure boundary layer with a comparable thickness, so accounting for the distributed shearing is necessary to model the system accurately. As expected, the finite-width fault zone distributes frictional work over a broader area, somewhat diminishing the thermal pressurization effect in comparison to zero-width fault models. Late in nucleation, we switch to a fully dynamic code that otherwise solves the same equations for friction and coupled thermal pressurization [Noda & others, JGR, 2009]. To evaluate the importance of accurately simulating the nucleation phase, we compare results to other dynamic simulations that include pressurization but do not include physically realistic nucleation. We also compare the effect of elastodynamics to prior results that make use of the quasi-dynamic ``radiation damping'' approximation. Results of simulations like these may have implications for the detection of precursory slip with near-source strainmeters or seismometers.

Schmitt, S. V.; Dunham, E. M.; Bradley, A. M.; Segall, P.

2010-12-01

50

Centre of pressure sway characteristics during static one-legged stance of athletes from different sports  

Microsoft Academic Search

The frequency of one-legged stance and two-legged stance differs considerably among sports. We therefore expect the balance ability of athletes from different sports to vary. This study compared the sway characteristics during a static one-legged stance of soccer players, basketball players, swimmers, and non-athletes. The centre of pressure sway during one-legged stance of ten male participants representing each of the

Shigeki Matsuda; Shinichi Demura; Masanobu Uchiyama

2008-01-01

51

Experimental investigation of power loss coefficients and static pressure ratios in an industrial exhaust ventilation system.  

PubMed

A study tested whether measures of equivalent resistance (X values) and ratios of static pressure (SPratio) for given ducts of contaminant control exhaust ventilation systems were independent of substantial changes to airflow level and to changes to resistance of other ducts within the same full-scale five-branch system. In a factorial study design, four airflow levels were achieved by changing fan rotation rate while resistances to flow for specific branch ducts were changed independently by adjusting slidegate dampers to various settings. For each damper insertion depth (including fully open), the results demonstrated substantial invariance for branch X values (few greater than 5%), SPratio (few greater than 3%), and fraction of airflow to each duct (few greater than 2%). X-values for submains were much less stable, changing by 20% or more with changes to other parts of the system. For the same conditions, hood static pressures changed by as much as 96% (with standard deviation of 40%). The results suggest that before and after values of X and SPratios should be more reliable bases for indicating alterations than comparison of observed static pressures. The stability of airflow distributions with substantial changes in airflow suggests that one could adjust airflow distribution (e.g., with dampers) without considering whether the fan speed was set correctly, leaving fan adjustments for a final step. PMID:10386358

Guffey, S E; Spann, J G

52

Effects of p-{rho}-T behavior of muds on static pressures during deep well drilling  

SciTech Connect

In this study, published p-{rho}-T data of twelve muds are compared using three models already proposed. The empirical model suggested by Kutasov is found to represent the measured data more accurately than the other models for a majority of the muds. With the help of the empirical model, an explicit equation is derived analytically to predict static pressures at different depths. Based on the analysis, an equivalent static density (ESD) variable is defined that incorporates the mud p-{rho}-T behavior, pressure and temperature of the mud at surface, thermal gradient, and depth of the well. It is suggested that ESD should be used in place of normally used mud weight term in all phases of deep well drilling. The analysis is applied to a high-temperature, 25,000-ft deep example well. It is observed that static pressure or ESD at the bottom of the well decreases during tripping and the extent of decrease is dependent on the type of mud. For the example well, it is estimated that a maximum reduction in ESD of about 0.62 lbm/gal occurs in the case of 18-lbm/gal water-based-mud, and a minimum reduction of about 0.2 lbm/gal occurs in the case of a 11-lbm/gal diesel-oil-based mud.

Babu, D.R.

1996-06-01

53

Tissue factor activity is increased in human endothelial cells cultured under elevated static pressure.  

PubMed

We tested the hypothesis that elevated blood pressure, a known stimulus for vascular remodeling and an independent risk factor for the development of atherosclerotic disease, can modulate basal and cytokine-induced tissue factor (TF; CD 142) expression in cultured human endothelial cells (EC). Using a chromogenic enzymatic assay, we measured basal and tumor necrosis factor-alpha (TNF-alpha; 10 ng/ml, 5 h)-induced TF activities in human aortic EC (HAEC) and vena cava EC (HVCEC) cultured at atmospheric pressure and at 170 mmHg imposed pressure for up to 48 h. Basal TF activities were 22 +/- 10 U/mg protein for HAEC and 14 +/- 9 U/mg protein for HVCEC and were upregulated in both cell types >10-fold by TNF-alpha. Exposure to pressure for 5 h induced additional elevation of basal TF activity by 47 +/- 16% (P < 0.05, n = 6) for HAEC and 17 +/- 5% (P < 0.05, n = 3) for HVCEC. Pressurization also enhanced TF activity in TNF-alpha-treated cells from 240 +/- 28 to 319 +/- 32 U/mg protein in HAEC (P < 0.05, n = 4) and from 148 +/- 25 to 179 +/- 0.8 U/mg protein (P < 0.05, n = 3) in HVCEC. Cytokine stimulation caused an approximately 100-fold increase in steady-state TF mRNA levels in HAEC, whereas pressurization did not alter either TF mRNA or cell surface antigen expression, as determined by quantitative RT-PCR methodology and ELISA. Elevated pressure, however, modulated the EC plasma membrane organization and/or permeability as inferred from the increased cellular uptake of the fluorescent amphipathic dye merocyanine 540 (33 +/- 7%, P < 0.05). Our data suggest that elevated static pressure modulates the hemostatic potential of vascular cells by modifying the molecular organization of the plasma membrane. PMID:10444399

Silverman, M D; Waters, C R; Hayman, G T; Wigboldus, J; Samet, M M; Lelkes, P I

1999-08-01

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

Bubble Pressure Generating System.  

National Technical Information Service (NTIS)

A pressure generating system uses a shock wave chamber filled with a liquid pressurized to a static pressure different from ambient atmospheric pressure. Once a preferred location is established in the chamber, a pulsed compressional acoustic shock wave i...

J. A. Clark

1995-01-01

56

30 CFR 550.1153 - When must I conduct a static bottomhole pressure survey?  

Code of Federal Regulations, 2013 CFR

...ensure stabilized conditions; and (2) The bottomhole pressure survey must consist of a pressure measurement at mid-perforation, and pressure measurements and gradient information for at least four gradient stops coming out of the hole....

2013-07-01

57

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

58

Effect of External or Internal Static Pressure on the Natural Frequencies of Unstiffened, Cross Stiffened, and Sandwich Cylindrical Shells.  

National Technical Information Service (NTIS)

A general formula is given for the natural frequency of a pressurized shell which is loaded with static load on its cylindrical surface as well as along its edge. It is found that the natural frequency of the pressurized shell can be written in terms of t...

J. E. Greenspon

1964-01-01

59

Static and dynamic pressure effects on the thermolysis of nitroalkanes in solution  

SciTech Connect

The authors have measured the effects of static and shock-induced pressures on the decomposition rates and mechanisms of various nitroalkanes dissolved in different solvents with and without organic amine catalysts. While nitroalkanes without {alpha}-hydrogen decompose by homolysis of the C-NO{sub 2} bond over a wide range of conditions, the decomposition pathway of nitroalkanes having {alpha}-hydrogens (i.e., acidic nitroalkanes) is complicated and follows different decomposition mechanisms depending on the availability of organic base and reaction pressure. The Nef reaction is also an important reaction pathway. The five known decomposition pathways, homolysis of the C-NO{sub 2} bond, bimolecular reaction between the aci-form and aci-ion, cyclization of the aci-form, elimination of nitrous acid, and the Nef reaction, are highly dependent on the reaction conditions, such as pressure, presence of organic amines, water, alcohols, and polarity of solvent. The authors discuss the results of several tests used to support these various decomposition mechanisms.

Brower, K.R. [New Mexico Inst. of Mining and Technology, Socorro, NM (United States). Dept. of Chemistry; Davis, L.L.; Naud, D.L. [Los Alamos National Lab., NM (United States); Wang, J. [Univ. of Southern California, Los Angeles, CA (United States). Dept. of Chemistry

1998-12-31

60

New Data for Aerosols Generated by Releases of Pressurized Powders and Solutions in Static Air  

SciTech Connect

Pacific Northwest Laboratory conducted three sets of experiments to measure aerosols generated by pressurized releases. These aerosols are generated from releases of uranine pressurized with carbon dioxide, flashing sprays, and low-pressure depleted uranium dioxide powder releases. The purpose of these experiments was to supplement data from earlier experiments investigating the source term from pressurized releases. These experiments are part of a program to develop source-term estimation methods for analysis of accidents in nuclear fuel cycle facilities.

MY Ballinger; SL Sutter; WH Hodgson

1987-04-01

61

Response of the cat eardrum to static pressures: Mobile versus immobile malleus  

NASA Astrophysics Data System (ADS)

A phase-shift shadow moiré interferometer was used to measure the shape of the cat eardrum with a normal mobile malleus and with an immobile malleus as it was cyclically loaded with static middle-ear pressures up to +/-2.2 kPa. The shape was monitored throughout the loading and unloading phases, and three complete cycles were observed. The mobile-manubrium measurements were made in five ears. In three ears, the malleus was then immobilized with a drop of glue placed on the head of the malleus. Eardrum displacements were calculated by subtracting shape images pixel by pixel. The measurements are presented in the form of gray-level full-field shape and displacement images, of displacement profiles, and of pressure-displacement curves for selected points. Displacement patterns with a mobile malleus show that pars-tensa displacements are larger than manubrial displacements, with the maximum pars-tensa displacement occurring in the posterior region in all cats except one. Displacements vary from cycle to cycle and display hysteresis. For both the mobile-malleus and immobile-malleus cases, the eardrum response is nonlinear. The response is asymmetric, with lateral displacements being larger than medial displacements. With a mobile malleus, manubrial displacements exhibit more pronounced asymmetry than do pars-tensa displacements. .

Ladak, Hanif M.; Decraemer, Willem F.; Dirckx, Joris J. J.; Funnell, W. Robert J.

2004-11-01

62

Centre of pressure sway characteristics during static one-legged stance of athletes from different sports.  

PubMed

The frequency of one-legged stance and two-legged stance differs considerably among sports. We therefore expect the balance ability of athletes from different sports to vary. This study compared the sway characteristics during a static one-legged stance of soccer players, basketball players, swimmers, and non-athletes. The centre of pressure sway during one-legged stance of ten male participants representing each of the four groups was measured using a stabilometer. Centre of pressure sway was assessed by four sway factors: sway velocity, anterior-posterior sway, horizontal sway, and high-frequency sway. None of the four groups of participants showed significant differences in body sway between standing on the dominant leg and standing on the non-dominant leg. The soccer players had more high-frequency sway and less anterior-posterior sway and horizontal sway than the basketball players, swimmers, and non-athletes. These results suggest that soccer players have superior ability to maintain a stable one-legged stance. Further study is required to determine how much of the superior balance ability in soccer players is innate and how much is developed through training, as well as to determine the relationship between balance ability and playing performance. PMID:18409108

Matsuda, Shigeki; Demura, Shinichi; Uchiyama, Masanobu

2008-05-01

63

Accurate method to study static volume-pressure relationships in small fetal and neonatal animals.  

PubMed

We designed an accurate method to study respiratory static volume-pressure relationships in small fetal and neonatal animals on the basis of Archimedes' principle. Our method eliminates the error caused by the compressibility of air (Boyle's law) and is sensitive to a volume change of as little as 1 microliters. Fetal and neonatal rats during the period of rapid lung development from day 19.5 of gestation (term = day 22) to day 3.5 postnatum were studied. The absolute lung volume at a transrespiratory pressure of 30-40 cmH2O increased 28-fold from 0.036 +/- 0.006 (SE) to 0.994 +/- 0.042 ml, the volume per gram of lung increased 14-fold from 0.39 +/- 0.07 to 5.59 +/- 0.66 ml/g, compliance increased 12-fold from 2.3 +/- 0.4 to 27.3 +/- 2.7 microliters/cmH2O, and specific compliance increased 6-fold from 24.9 +/- 4.5 to 152.3 +/- 22.8 microliters.cmH2O-1.g lung-1. This technique, which allowed us to compare changes during late gestation and the early neonatal period in small rodents, can be used to monitor and evaluate pulmonary functional changes after in utero pharmacological therapies in experimentally induced abnormalities such as pulmonary hypoplasia, surfactant deficiency, and congenital diaphragmatic hernia. PMID:8002489

Suen, H C; Losty, P D; Donahoe, P K; Schnitzer, J J

1994-08-01

64

Study of the laser-induced decomposition of HNO3/ 2-Nitropropane mixture at static high pressures  

NASA Astrophysics Data System (ADS)

HNO3 / 2-Nitropropane is a well known energetic material on which Raman spectroscopy measurements at static high pressure in a diamond anvil cell (DAC) have already been conducted at CEA/LE RIPAULT in order to examine the evolution of the mixture as a function of composition and pressure [1]. The purpose of the work presented here was to study the laser-induced decomposition of these energetic materials at static high pressures by measuring the combustion front propagation rate in the DAC. First of all, the feasibility of the experimental device was checked with a well known homogeneous explosive, nitromethane. Our results were consistent with those of Rice and Foltz [2]. Then, we investigated the initiation of NA / 2NP mixture as a function of nitric acid proportion, for a given pressure. We chose the mixture for which both the combustion propagation rate and detonation velocity are maximum and we examined the evolution of the front propagation velocity as a function of pressure and energy deposit. [1] Hebert, P., Regache, I., and Lalanne, P., ``High-Pressure Raman Spectroscopy study of HNO3 / 2-Nitropropane Mixtures. Influence of the Composition.'' Proceedings of the 42nd European High-Pressure Research Group Meeting, Lausanne, Suisse, 2004 [2] Rice, S.F., et al., Combustion and Flame 87 (1991) 109-122.

Bouyer, Viviane; Hébert, Philippe; Doucet, Michel

2007-06-01

65

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

Microsoft Academic Search

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

Di-xian Luo; Jiming Cheng; Yan Xiong; Junmo Li; Chenglai Xia; Canxin Xu; Chun Wang; Bingyang Zhu; Zhuowei Hu; Duan-fang Liao

2010-01-01

66

Two-stage consolidation of silicon nitride under static gas pressure  

Microsoft Academic Search

.Dense components made of materials based on silicon nitride are usually produced by hot pressing followed by expensive size machining. Sintering without pressurization enables one to make components of almost any shape, but with densities lower than for hot-pressed ones. The thermal stability of silicon nitride is raised at high nitrogen pressures, and this has made it necessary to examine

P. S. Kislyi; V. M. Filipenko

1992-01-01

67

Structural and Chemical Changes in Pyrene Crystals under Static High Pressures  

Microsoft Academic Search

To gain insight into the response of molecular crystals to high pressures, pyrene crystals were examined in diamond-anvil cell experiments using Raman and FTIR spectroscopy. Three distinct Raman spectra were observed around 0.5 GPa, depending on the type of pressure transmitting medium. It was demonstrated that pyrene I: (i) transforms to pyrene II, in water and mineral oil, (ii) transforms

Baozhou Sun; Zbigniew Dreger; Yogendra Gupta

2007-01-01

68

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

69

THE EFFECTS OF CONFINING PRESSURE AND STRESS DIFFERENCE ON STATIC FATIGUE OF GRANITE  

Microsoft Academic Search

Samples of Barre granite were creep creasing depth. The transition depth, where creep tested at room temperature at confining pressures rupture is no longer possible owing to increasing up to 2 kbar. The time to fracture increased ductility, is unknown. It is significant that with decreasing stress difference at every dilatancy caused by microfracturing occurs in pressure. The time to

Robert L. Kranzl

1980-01-01

70

Experimental and numerical determination of the static critical pressure in ferrofluid seals  

NASA Astrophysics Data System (ADS)

Ferrofluids have various engineering applications; one of them are magnetic fluid seals for rotating shafts. There are various constructions of this type of seals, but the main difference is the number of sealing stages. The development of this construction is a complex process which requires knowledge of ferrofluid physical and rheological properties and the magnetic field distribution inside the sealing gap. One of the most important parameters of ferrofluid seals is the critical (burst) pressure. It is the pressure value at which a leak will occur. This study presents results of numerical simulation of magnetic field distribution inside the seal gap and calculations of the critical pressure value. The obtained pressure values were verified by experiments.

Horak, W.; Szcz?ch, M.

2013-02-01

71

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

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

Pressure-induced transition from the dynamic to static Jahn-Teller effect in (Ph4P)2IC60  

NASA Astrophysics Data System (ADS)

High-pressure infrared transmission measurements on (Ph4P)2IC60 were performed up to 9 GPa over a broad frequency range (200-20000 cm-1) to monitor the vibrational and electronic/vibronic excitations under pressure. The four fundamental T1u modes of C60- are split into doublets already at the lowest applied pressure and harden with increasing pressure. Several cation modes and fullerene-related modes split into doublets at around 2 GPa, the most prominent one being the G1u mode. The splitting of the vibrational modes can be attributed to the transition from the dynamic to static Jahn-Teller effect, caused by steric crowding at high pressure. Four absorption bands are observed in the NIR-visible frequency range. They are discussed in terms of transitions between LUMO electronic states in C60-, which are split because of the Jahn-Teller distortion and can be coupled with vibrational modes. Various distortions and the corresponding symmetry lowering are discussed. The observed redshift of the absorption bands indicates that the splitting of the LUMO electronic states is reduced upon pressure application.

Francis, E. A.; Scharinger, S.; Németh, K.; Kamarás, K.; Kuntscher, C. A.

2012-05-01

74

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

75

Structural and Chemical Changes in Pyrene Crystals under Static High Pressures  

NASA Astrophysics Data System (ADS)

To gain insight into the response of molecular crystals to high pressures, pyrene crystals were examined in diamond-anvil cell experiments using Raman and FTIR spectroscopy. Three distinct Raman spectra were observed around 0.5 GPa, depending on the type of pressure transmitting medium. It was demonstrated that pyrene I: (i) transforms to pyrene II, in water and mineral oil, (ii) transforms to pyrene III, in argon and nitrogen and (iii) remains in the same phase, in solid media. These changes are discussed in terms of nonhydrostaticity of pressure transmitting media and intercalation of medium and sample. Irreversible chemical changes were observed upon compressing pyrene above 25 and 40 GPa. Recovered product was examined using FTIR spectroscopy indicating gradual transformation to an amorphous hydrogenated carbon structure. Work supported by DOE and ONR.

Sun, Baozhou; Dreger, Zbigniew; Gupta, Yogendra

2007-06-01

76

Inelastic X-ray scattering experiments on B[subscript 4]C under high static pressures  

SciTech Connect

Boron K-edge inelastic X-ray scattering experiments were performed on clean B{sub 4}C and shock impact recovered boron carbide up to 30 GPa and at ambient temperature to understand the pressure induced bonding changes. The spectral features corresponding to the boron site in the interlinking chain remained unchanged up to 30 GPa. The results of our experiments indicate that pressure induces less distortion to the boron sites and the local amorphization observed in the previous reports are due to the rearrangement of carbon atoms under extreme conditions without affecting the boron environment.

Kumar, Ravhi S.; Dandekar, Dattatraya; Leithe-Jasper, Andres; Tanaka, Takaho; Xiao, Yuming; Chow, Paul; Nicol, Malcolm F.; Cornelius, Andrew L. (UNLV); (MXPL-M); (CIW); (USARL)

2010-05-04

77

Static pressure-volume curves and body posture in severe chronic bronchitis  

Microsoft Academic Search

Based on prior data, the current authors hypothesised that beneficial pronation effects on gas exchange and respiratory mechanics might be maximised in severely hyperinflated chronic bronchitis patients. The current authors also sought to elucidate underlying mechanisms and to determine whether pronation effects are reflected by postural changes in inspiratory pressure-volume (P-V) curve characteristics. A total of 16 mechanically ventilated patients

S. D. Mentzelopoulos; J. Sigala; C. Roussos; S. G. Zakynthinos

2006-01-01

78

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

79

Blood pressure  

MedlinePLUS Videos and Cool Tools

Normal blood pressure is important for proper blood flow to the body’s organs and tissues. The force of the blood on the walls of the arteries is called blood pressure. Blood pressure is measured both as the heart ...

80

Pressure Sores  

MedlinePLUS

... may form. Pressure sores are also called bedsores, pressure ulcers and decubitus ulcers. Symptoms What are the symptoms ... put in a vein) or orally (by mouth). Prevention How can pressure sores be prevented? The most important step to ...

81

Static pressure volume curves and body posture in acute respiratory failure  

Microsoft Academic Search

Objective: In acute respi- ratory distress syndrome the body posture effects on pressure-volume (PV) curves are still unclear. We ex- amined the effects of prone position on inflation PV curves and their po- tential relationships with postural al- terations in gas exchange. Design and setting: Prospective study with pa- tients serving as their own controls in a university-affiliated 30-bed inten-

Spyros D. Mentzelopoulos; Charis Roussos; Spyros G. Zakynthinos

2005-01-01

82

Static and dynamic pressure prediction for prosthetic socket fitting assessment utilising an inverse problem approach  

Microsoft Academic Search

ObjectiveIt has been recognised in a review of the developments of lower-limb prosthetic socket fitting processes that the future demands new tools to aid in socket fitting. This paper presents the results of research to design and clinically test an artificial intelligence approach, specifically inverse problem analysis, for the determination of the pressures at the limb\\/prosthetic socket interface during stance

Philip Sewell; Siamak Noroozi; John Vinney; Ramin Amali; Stephen Andrews

83

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.

84

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

2011-11-30

85

Phenomenon of labyrinth weal with Low static pressure difference and large clearance  

Microsoft Academic Search

Absract  The low pressure axial flow fans with an outer ring, used for cooling automobile radiators, have a significantly large tip\\u000a clearance between the ring tip and the fan shroud. It has been found that the turbulent reverse flow, or leakage flow, which\\u000a occurs at the tip clearance, greatly affects the fan performance and noise level. Therefore, in order to improve

K. Kimura; H. Ohta; K. Aoki

2003-01-01

86

Influence of static pressure and shear rate on hemolysis of red blood cells.  

PubMed

The purpose of this study was to investigate the effect of multiple mechanical forces in hemolysis. Specific attention is focused on the effects of shear and pressure. An experimental apparatus consisting of a rotational viscometer, compression chamber, and heat exchanger was prepared to apply multiple mechanical forces to a blood sample. The rotational viscometer, in which bovine blood was subjected to shear rates of 0, 500, 1,000, and 1,500 s(-1), was set in the compression chamber and pressurized with an air compressor at 0, 200, 400, and 600 mm Hg. The blood temperature was maintained at 21 degrees C and 28 degrees C. Free hemoglobin at 600 mm Hg was observed to be approximately four times higher than at 0 mm Hg for a shear rate of 1,500 s(-1) (p < 0.05). The results suggest that the increase in hemolysis is strongly related to pressure when high shear rates are applied to the erythrocytes. The data acquired in this study will be helpful in the development of artificial organs, where it will facilitate the prediction of hemolysis in flow dynamics analysis, flow visualization, and computational fluid dynamics. PMID:11482485

Yasuda, T; Funakubo, A; Miyawaki, F; Kawamura, T; Higami, T; Fukui, Y

87

Static pressure-volume curve characteristics are moderate estimators of optimal airway pressures in a mathematical model of (primary\\/pulmonary) acute respiratory distress syndrome  

Microsoft Academic Search

Objective: To study the value of objective pressure-volume characteristics for predicting optimal airway pressures and the develop- ment of atelectasis and overstretching during a structured lung volume re- cruitment procedure with subse- quent reduction in airway pressures. Methods: We used a mathematical model of a lung with adjustable characteristics of acute respiratory distress syndrome (ARDS) charac- teristics. Simulations were performed

Dick G. Markhorst; Huibert R. van Genderingen; Adrianus J. van Vught

2004-01-01

88

Study of the Laser-Induced Decomposition of HNO3/2-NITROPROPANE Mixture at Static High Pressure  

NASA Astrophysics Data System (ADS)

The objective of the work presented here is to study the laser-induced decomposition of a condensed HNO3/2-nitropropane mixture containing 58% nitric acid. On the macroscopic scale, this energetic material detonates. Under static high pressure, the formation of an H-bonded complex with that particular composition was demonstrated in a previous study. The high pressure behavior of the complex showed the presence of a solid-solid phase transition around 18 GPa. The combustion front propagation velocity was recorded between 6 and 31 GPa. The analysis of the optical properties of the reaction products as well as the recording of their Raman spectra showed two different combustion regimes. Below 18 GPa, total combustion takes place in the sample and a black residue only composed of soot remains in the cell. Above 18 GPa, the combustion leads to a clear residue with little carbon present. However, the Raman spectra of the remaining sample show new features indicating the presence of species which are not yet clearly identified. The pressure limit between these two behaviors corresponds to the phase transition pressure measured for the complex.

Bouyer, V.; Hébert, P.; Doucet, M.

2007-12-01

89

Study of the laser-induced decomposition of HNO{sub 3}/2-nitropropane mixture at static high pressure  

SciTech Connect

The objective of the work presented here is to study the laser-induced decomposition of a condensed HNO{sub 3}/2-nitropropane mixture containing 58% nitric acid. On the macroscopic scale, this energetic material detonates. Under static high pressure, the formation of an H-bonded complex with that particular composition was demonstrated in a previous study. The high pressure behavior of the complex showed the presence of a solid-solid phase transition around 18 GPa. The combustion front propagation velocity was recorded between 6 and 31 GPa. The analysis of the optical properties of the reaction products as well as the recording of their Raman spectra showed two different combustion regimes. Below 18 GPa, total combustion takes place in the sample and a black residue only composed of soot remains in the cell. Above 18 GPa, the combustion leads to a clear residue with little carbon present. However, the Raman spectra of the remaining sample show new features indicating the presence of species which are not yet clearly identified. The pressure limit between these two behaviors corresponds to the phase transition pressure measured for the complex.

Bouyer, V.; Hebert, P.; Doucet, M. [CEA/DAM Le Ripault, Tours (France)

2007-12-12

90

Effect of pore water pressure on tunnel support during static and seismic loading  

Microsoft Academic Search

The support of underground structures must be designed to withstand static overburden loads as well as seismic loads. New analytical solutions for a deep tunnel in a saturated poroelastic ground have been obtained for static and seismic loading. The static solution accounts for drainage and no-drainage conditions at the ground–liner interface. Linear elasticity of the liner and ground, and plane

A. Bobet

2003-01-01

91

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

NASA Astrophysics Data System (ADS)

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, in turn, depends on the interfacial tension between wetting and non-wetting phases, the pore size distribution of the porous material as well as the contact angle between fluids and porous media. Traditionally, measurements of the Pc-S relationship were carried out using pressure cells but these methods can be very time consuming. The objective of this research was to implement the innovative technique of light transmission visualization (LTV) to investigate the Pc-S relationships for porous media, and compare the results to an independent technique, namely a rapid pseudo-static automated method that was recently developed by Chen et al. Two dimensional (2-D) chambers constructed of two glass plates were packed with either 20/30 or 40/60 silica sand and then fully saturated with water. Images of the entire 2-D chambers were captured using a charge- coupled device (CCD) camera and analyzed pixel by pixel to determine air and water saturation in the porous media. Variable saturation of water and air across the height of the chamber was dictated by controlling the capillary pressure of the fluids. The primary drainage curve, main imbibition curve and secondary drainage curve were all measured, for the first time, using LTV and the results were compared to the results obtained by the rapid pseudo-static method. Overall, there was good agreement between the results of the two methods and variation in air entry pressure that was calculated based on Brooks-Cory model was within 2 cm for the sand sizes tested. Both techniques are capable of providing high spatial resolution data for the Pc-S relationships. Disclaimer This is an abstract of a proposed presentation and does not necessarily reflect EPA policy.

Bob, M. M.; Brooks, M. C.; Chen, L.; Kibbey, T. C.; Wood, L.

2008-12-01

92

Three-dimensional unsteady flow and forces in centrifugal impellers with circumferential distortion of the outlet static pressure  

SciTech Connect

This paper describes the numerical investigation of the centrifugal impeller response to downstream static pressure distortions imposed by volutes at off-design operations. An unsteady three-dimensional Euler solver with nonreflecting upstream and downstream boundary conditions and phase-lagged periodicity conditions is used for this purpose. The mechanisms governing the unsteady flow field are analyzed. A parametric study shows the influence of the acoustic Strouhal number on the amplitude of the flow perturbations. Radial forces calculated on backward leaned and radial ending centrifugal impellers show nonnegligible influence of the impeller geometry.

Fatsis, A.; Pierret, S.; Braembussche, R. van den [von Karman Inst. for Fluid Dynamics, Rhode-St.-Genese (Belgium). Turbomachinery Dept.

1997-01-01

93

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

94

NEW DPharp EJX SERIES PRESSURE AND DIFFERENTIAL PRESSURE TRANSMITTERS  

Microsoft Academic Search

We have newly developed the DPharp EJX series of pressure and differential pressure transmitters with the advanced silicon resonant sensor. The DPharp EJX series employs a multi-sensing technology that enables both differential pressure and static pressure to be measured simultaneously. This technology eliminates the need for pressure gauges, contributing to cost reductions in plant installations. Moreover, the silicon resonant sensor

ISHIKAWA Tamaki; ODOHIRA Tetsu; NIKKUNI Masaaki; KOYAMA Etsutaro; TSUMAGARI Tetsurou; ASADA Ryuuzou

95

Under pressure.  

PubMed

Physical urticaria is a rare but challenging subset of chronic urticaria. Wheals of pressure urticaria are typically delayed in appearance. A pressure test can easily be done to confirm the diagnosis. PMID:22968937

De Cunto, Angela; Berti, Irene; Minute, Marta; Longo, Giorgio

2012-09-12

96

Pressure Controller  

NASA Astrophysics Data System (ADS)

EPIC is Electronic Pressure Indicating Controller produced by North American Manufacturing Company. It is a high-sensitivity device for improving combustion efficiency in industrial furnaces that interprets a signal from a pressure transducer on a furnace and regulates furnace pressure accordingly. A controller can provide savings of from five to 25 percent of an industrial user's annual furnace fuel bill.

1981-01-01

97

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

98

The Effect of Static Ear Canal Pressure on Human Spontaneous Otoacoustic Emissions: Spectral Width as a Measure of the Intra-cochlear Oscillation Amplitude  

PubMed Central

Spontaneous otoacoustic emissions can be detected as peaks in the Fourier spectrum of a microphone signal recorded from the ear canal. The height, center frequency, and spectral width of SOAE peaks changed when a static pressure was applied to the ear canal. Most commonly, with either increasing or decreasing static pressure, the frequency increased, the amplitude decreased, and the width increased. These changes are believed to result from changes in the middle ear properties. Specifically, reduced middle ear transmission is assumed to attenuate the amplitude of emissions. We reconsidered this explanation by investigating the relation between peak height and width. We showed that the spectral width of SOAE peaks is approximately proportional to \\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$ 1/\\sqrt {{{\\hbox{peak}}\\;{\\hbox{height}}}} $$\\end{document}. This is consistent with a (Rayleigh) oscillator model in which broadening of the SOAE peak is caused by broadband intra-cochlear noise, which is assumed to be independent of static ear canal pressure. The relation between emission peak height and width implicates that the intra-cochlear oscillation amplitude attentuates relative to the intra-cochlear noise level when a static ear canal pressure is applied. Apparently, ear canal static pressure directly affects the active mechanics in the inner ear.

Maat, Bert; de Kleine, Emile

2010-01-01

99

Static recrystallization of vein quartz pebbles in a high-pressure - low-temperature metamorphic conglomerate  

NASA Astrophysics Data System (ADS)

Microfabrics of quartz pebbles in HP-LT (c. 1 GPa, c. 350 °C) metamorphic conglomerates are investigated. The conglomerate was deformed by dissolution-precipitation creep, while the interior of the pebbles remained undeformed. The different pebbles display a wide variety of quartz microstructures imported from the source rocks. One type of pebble is derived from quartz veins; it shows old grains with numerous fluid inclusions, subgrains, and undulatory extinction, which are partly replaced by new grains devoid of inclusions and substructure. Free dislocation densities are on the order of 1012 m-2 in both grains. We conclude that: (1) the quartz vein underwent inhomogeneous crystal-plastic deformation in the source rock; (2) recrystallization took place by strain-induced grain boundary migration starting from small crystalline volumes poor in defects; (3) recrystallization was purely static and commenced during re-burial of the conglomerate; which (4) was simultaneously deformed by dissolution-precipitation creep at low differential stress, insufficient for crystal-plastic deformation of quartz; (5) fluid inclusions within old grains were eliminated and their fluid content was drained along the migrating high angle grain boundaries; and (6) strain-induced grain boundary migration ceased once the driving force became too low by static recovery (concurrent to recrystallization) within the deformed old grains.

Trepmann, Claudia; Lenze, Annette; Stöckhert, Bernhard

2010-02-01

100

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

Microsoft Academic Search

The high-pressure behavior of the lattice elasticity of spodumene, LiAlSi2O6,\\u000awas studied by static compression in a diamond-anvil cell up to 9.3 GPa.\\u000aInvestigations by means of single-crystal XRD and Raman spectroscopy within the\\u000ahydrostatic limits of the pressure medium focus on the pressure ranges around\\u000asimilar to 3.2 and similar to 7.7 GPa, which have been reported previously to

A. Ullrich; W. Schranz; R. Miletich

2010-01-01

101

Effects of static electric field and of mechanical pressure on surface acoustic waves propagation in La3Ga5SiO 14 piezoelectric single crystals  

Microsoft Academic Search

The complete set of tensorial components of linear and nonlinear electromechanical properties for La3Ga5SiO14 , piezoelectric crystals have been obtained. These data were used for the analysis of influence of static electric field and of uniaxial homogeneous mechanical pressure on the propagation of surface acoustic waves

K. S. Aleksandrov; B. P. Sorokin; P. P. Turchin; S. I. Burkov; D. A. Glushkov; A. A. Karpovich

1995-01-01

102

[The behavior of arterial blood pressure in dynamic and static muscle exercise with respect to atrial natriuretic peptide and neurotransmitters].  

PubMed

The development of the first semi-automatic blood pressure measuring instrument including optic and acoustic registration of systolic and diastolic blood pressure has led to a reliable assessment of arterial blood pressure during increasing ergometer exercise. There is a linear connection between workload intensity and systolic pressure. Intraarterially and noninvasively obtained values are identical with regard to systolic behavior. In principle, the intraarterially measured diastolic blood pressure, too, increases in healthy subjects, which, nevertheless, may often not be demonstrated in such a clear way due to artefacts occurring during blood pressure measuring. There are no significant differences between untrained and endurance-trained subjects at a given work load. Persons exhibiting a better performance capacity only reach higher maximal systolic values. The male and female subjects' regression lines significantly differ--the reason possibly being the woman's smaller muscle mass. Age-induced differences, too, are significant. Bodybuilders with extremely developed muscle mass do not show any significant differences with regard to blood pressure behavior during exercise. When establishing a relation to the relative muscle force the bodybuilders show blood pressure values even lower than normal values. PMID:2533766

Hollmann, W; Völker, K; Heck, H; Rost, R; De Meirleir, K

1989-01-01

103

Pressure Sensors  

Microsoft Academic Search

\\u000a The concept of pressure was primarily based on the pioneering work of Evangelista Torricelli who for a short time was a student\\u000a of Galileo [1]. During his experiments with mercury filled dishes, in 1643, he realized that the atmosphere exerts pressure on Earth. Another\\u000a great experimenter Blaise Pascal, in 1647, conducted an experiment with the help of his brother-in-law, Perier,

Jacob Fraden

104

Pressure regulator  

DOEpatents

The pressure within a pressurized flow reactor operated under harsh environmental conditions is controlled by establishing and maintaining a fluidized bed of uniformly sized granular material of selected density by passing the gas from the reactor upwardly therethrough at a rate sufficient to fluidize the bed and varying the height of the bed by adding granular material thereto or removing granular material therefrom to adjust the backpressure on the flow reactor.

Ebeling, Jr., Robert W. (Reading, PA); Weaver, Robert B. (Reading, PA)

1979-01-01

105

A new simple method to perform pressure-volume curves obtained under quasi-static conditions during mechanical ventilation  

Microsoft Academic Search

Objective: To describe a fast, simple method to acquire pressure-volume curves of the respiratory system and to compare this with a\\u000a classic method in terms of reliability of the data and speed. Design: Acquisition of pressure-volume curves by low flow inflation technique (P-Vlf) versus the occlusion technique (P-Vst) using\\u000a the standard equipment of a Cesar ventilator. Setting: General ICU –

L. Rodriguez; B. Marquer; P. Mardrus; F. Molenat; J. L. Le Grand; M. Reboul; B. Garrigues

1999-01-01

106

Flat feet, happy feet? Comparison of the dynamic plantar pressure distribution and static medial foot geometry between Malawian and Dutch adults.  

PubMed

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. PMID:23468936

Stolwijk, Niki M; Duysens, Jacques; Louwerens, Jan Willem K; van de Ven, Yvonne Hm; Keijsers, Noël Lw

2013-02-28

107

Influence of static electric field, mechanical pressure and temperature on the propagation of acoustic waves in La3Ga5SiO14 piezoelectric single crystals  

Microsoft Academic Search

On the fundamental of our original experimental results the full set of tensorial components of linear and nonlinear electromechanical properties and temperature coefficients of material properties for La 3Ga5SiO14 piezoelectric crystals have been obtained. These data were used for the analysis of influence of static electrical field and of uniaxial homogeneous mechanical pressure on the propagation anisotropy of acoustic waves

B. P. Sorokin; P. P. Turchin; S. I. Burkov; D. A. Glushkov; K. S. Aleksandrov

1996-01-01

108

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

109

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

110

Pressure transducer  

DOEpatents

A pressure transducer suitable for use in high temperature environments includes two pairs of induction coils, each pair being bifilarly wound together, and each pair of coils connected as opposite arms of a four arm circuit; an electrically conductive target moveably positioned between the coil pairs and connected to a diaphragm such that deflection of the diaphragm causes axial movement of the target and an unbalance in the bridge output.

Anderson, Thomas T. (Downers Grove, IL); Roop, Conard J. (Lockport, IL); Schmidt, Kenneth J. (Midlothian, IL); Gunchin, Elmer R. (Lockport, IL)

1989-01-01

111

Pressure drop and cavitation investigations on static helical-grooved square, triangular and curved cavity liquid labyrinth seals  

Microsoft Academic Search

Sodium cooled Fast Breeder Reactors (FBR) form the second stage of India's Nuclear power programme. Through a narrow annular space in the grid plate assembly of a prototype FBR, a very low leakage flow of liquid metal sodium should pass, experiencing a stipulated high pressure drop, and without much cavitation. To achieve this, a suitable labyrinth seal is required to

S. P. Asok; K. Sankaranarayanasamy; T. Sundararajan; G. Vaidyanathan; K. Udhaya Kumar

2011-01-01

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

Ambient Pressure Probe.  

National Technical Information Service (NTIS)

The patent application relates to a device whereby ambient or static pressure in a fluid stream is sensed with a hollow circular cylinder placed normal to the fluid stream. A shroud is mounted on the cylinder for adjustment over a ring of ports provided i...

R. D. Marshall

1975-01-01

114

Blood Pressure Test  

MedlinePLUS

... blood pressure reading — is the pressure of the blood flow when your heart muscle contracts. Diastolic pressure — the bottom number of your blood pressure reading — is the pressure measured between heartbeats. ...

115

On the propagation of a quasi-static disturbance in a heterogeneous, deformable, and porous medium with pressure-dependent properties  

SciTech Connect

Using an asymptotic technique, valid when the medium properties are smoothly-varying, I derive a semi-analytic expression for the propagation velocity of a quasi-static disturbance traveling within a nonlinear-elastic porous medium. The phase, a function related to the propagation time, depends upon the properties of the medium, including the pressure-sensitivities of the medium parameters, and on pressure and displacement amplitude changes. Thus, the propagation velocity of a disturbance depends upon its amplitude, as might be expected for a nonlinear process. As a check, the expression for the phase function is evaluated for a poroelastic medium, when the material properties do not depend upon the fluid pressure. In that case, the travel time estimates agree with conventional analytic estimates, and with values calculated using a numerical simulator. For a medium with pressure-dependent permeability I find general agreement between the semi-analytic estimates and estimates from a numerical simulation. In this case the pressure amplitude changes are obtained from the numerical simulator.

Vasco, D.W.

2011-10-01

116

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

117

Pressure transducer  

US Patent & Trademark Office Database

Sensing and electrical-signal characterization of fluid pressures is effected by a miniature precision transducer manufacturable at low cost from a combination of a pair of sub-assemblies, one of which consists of a single-piece metal transducer element having a flanged body with a blind-hole port leading from a mechanical pressure fitting to the inner side of a transverse thin diaphragm which forms the blunt flat end of the body except for a bonded covering of both the machined outer side of the diaphragm and its coplanar annular rigid rim by a foil-type rosette strain gage bridge array and its layer of supporting insulation. Both the contact tabs and certain abradable resistance components of the flat foil bridge array are distributed about and disposed in overlying adjacent relation to the rigid annular rim of the body, where there is accessibility for convenient testing and adjustment and electrical contacting before a second sub-assembly, which serves as a seal and electrical connector, is fitted over the closed end of the body in a protective and electrically-coupled relation to the gaged diaphragm.

Studlien; Vance D. (Stow, MA)

1981-10-13

118

Pressure control in drilling. Pt. 5. Pressures and pressure gradients  

Microsoft Academic Search

The relationship of imposed pressure and pressure gradients is the key to lost circulation during well kicks. The usual hazard during a well-killing procedure is lost circulation caused by pressure exerted on the formation. This can result in an underground blowout. Drilling mud in a well bore exerts a pressure that is proportional to depth. Fracturing in the well bore

Rehm

1969-01-01

119

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

120

The finite displacement analysis of the circular aluminum plate subjected to hydro static pressure with Semi-Analytical finite ring element  

NASA Astrophysics Data System (ADS)

The rocking motion of tanks due to earthquakes causes the uplift and partial of large deformation of the tank bottom plate that has been considered to contribute to the various damage of the tanks. For analyzing the stress of the tank bottom plate numerically, this paper develops the analytical finite ring element with effects of the large deformation. The ring element is defined as a semi-analytical model. Fourier series give its circumferential displacement function, while polynomial gives its radial displacement function. For evaluating analytical accuracy of the proposed method, numerical results are compared with experimental ones that measure deformation of circular aluminum plate subjected to hydro static pressure.

Nakashima, Teruhiro; Taniguchi, Tomoyo

121

Study on a decagonal quasicrystal and an approximate crystalline phase in Al70Co15Ni10Tb5 obtained by quenching under high static pressure  

NASA Astrophysics Data System (ADS)

A decagonal quasicrystal and a new crystalline approximant of the decagonal quasicrystal have been found in Al70Co15Ni10Tb5 alloy, which was prepared by a method of quenching from the melt under a high static pressure 7.0 GPa. The lattice parameters of the new crystalline approximant are a = 2.28 nm, b = 1.60 nm, c = 5.46 nm. A lattice image of the approximant was obtained by means of high-resolution electron microscopy and was able to be regarded as an ordered pattern of Penrose tiling. Based on the lattice image, a tiling model of the approximant was put forward.

Yu, R. C.; Xu, D. P.; Su, W. H.

1995-09-01

122

Differential pressure pin discharge apparatus  

DOEpatents

Disclosed is a discharge assembly for allowing elongate pins to be discharged from an area of relatively low pressure to an area of relatively greater pressure. The discharge assembly includes a duck valve having a lip piece made of flexible material. The flexible lip piece responds to a fluctuating pressure created downstream by an aspirator. The aspirator reduces the downstream pressure sensed by the duck valve when the discharge assembly is in the open position. This allows elongate pins to be moved through the duck valve with no backflow because the aspirator pressure is less than the pressure in the low pressure area from which the pins originate. Closure of the assembly causes the aspirator static pressure to force the flexible duck valve lip piece into a tightly sealed position also preventing backflow. The discharge assembly can be easily controlled using a single control valve which blocks the flow of aspirator gas and closes the pins passageway extending through the assembly.

Oakley, D.J.

1984-05-30

123

Differential pressure pin discharge apparatus  

DOEpatents

Disclosed is a discharge assembly for allowing elongate pins to be discharged from an area of relatively low pressure to an area of relatively greater pressure. The discharge assembly includes a duck valve having a lip piece made of flexible material. The flexible lip piece responds to a fluctuating pressure created downstream by an aspirator. The aspirator reduces the downstream pressure sensed by the duck valve when the discharge assembly is in the open position. This allows elongate pins to be moved through the duck valve with no backflow because the aspirator pressure is less than the pressure in the low pressure area from which the pins originate. Closure of the assembly causes the aspirator static pressure to force the flexible duck valve lip piece into a tightly sealed position also preventing backflow. The discharge assembly can be easily controlled using a single control valve which blocks the flow of aspirator gas and closes the pin passageway extending through the assembly.

Oakley, David J. (Richland, WA)

1987-01-01

124

Dynamic and Static Shell Properties of White and Brown Shell Eggs Exposed to Modified-pressure Microcrack Detection Technology  

Technology Transfer Automated Retrieval System (TEKTRAN)

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 egg reaching consumers. A study was conducted to determine if dynamic she...

125

Pressure noise in pressurized water reactors  

Microsoft Academic Search

A general study of pressure fluctuations (noise) in the primary coolant loop of pressurized water reactors (PWRs) was performed. The study included noise sources, PWR pressure dynamics, and pressure-noise measurements. A detailed model of noise in the Loss-of-Fluid Test (LOFT) Facility was developed and compared against measurements. The potential of pressure-noise measurements for reactor monitoring and diagnosis of problems was

J. A. Mullens; J. A. Thie

1985-01-01

126

Ultrahigh pressure diamond-anvil cell and several semiconductor phase transition pressures in relation to the fixed point pressure scale  

Microsoft Academic Search

A diamond-anvil type optical cell of improved design has produced static pressures in gasketed samples up to 500 kilobar as measured by the ruby fluorescence technique. The ruby R1 line pressure shift is linear to 291 kilobar, and the maximum measured shift is extrapolated to 500 kilobar assuming continued linearity of the pressure dependence. The ultimate pressure capability of this

G. J. Piermarini; S. Block

1975-01-01

127

Pressure noise in pressurized water reactors  

SciTech Connect

A general study of pressure fluctuations (noise) in the primary coolant loop of pressurized water reactors (PWRs) was performed. The study included noise sources, PWR pressure dynamics, and pressure-noise measurements. A detailed model of noise in the Loss-of-Fluid Test (LOFT) Facility was developed and compared against measurements. The potential of pressure-noise measurements for reactor monitoring and diagnosis of problems was assessed, particularly collapse of the pressurizer steam bubble, loss of subcooling, and sensing-line defects. 26 refs., 30 figs., 12 tabs.

Mullens, J.A.; Thie, J.A.

1985-12-01

128

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

129

Pressure Fluctuating Tool  

Microsoft Academic Search

The Pressure Fluctuating Tool (PFT) utilizes a fluidic oscillator to create pulsating pressure for breaking down perforations. The maximum pressure fluctuations produced by the oscillator can be as great as 1500 psi (10,300 kPa) above and below downhole ambient pressure with frequency ranging from 140 to 160 cycles per second. Pressure fluctuations are greatest in the primary oscillation zone located

R. A. Payne; K. A. Williams; L. L. Pelty; H. L. Bailey

1985-01-01

130

Cerebrospinal fluid pressure1  

Microsoft Academic Search

The cerebrospinal fluid pressure at the foramen of Monro in man in the recumbent position is less than 100 mm water relative to atmospheric pressure. The oscillations in the pressure wave due to respiration and cardiac pulsation vary with the actual pressure and increase as the overall pressure rises. In man lying horizontally the oscillation at the foramen of Monro

K. C. Bradley

1970-01-01

131

Optical Nd 3+ Y 2 O 3 ceramics of nanopowders compacted by static pressure using the ultrasonic method  

Microsoft Academic Search

The possibility of synthesizing technological Nd3+Y2O3 and Y2O3 optically transparent ceramics is studied. This technology is different from the conventional approaches, because the compacting\\u000a was performed using the uniaxial static compression with ultrasonic treatment of the compacted nanopowder. It was found that\\u000a the relative compact density in the case of compaction of weakly agglomerated powders with an average particle size

V. V. Osipov; O. L. Khasanov; V. A. Shitov; E. S. Dvilis; M. G. Ivanov; A. N. Orlov; V. V. Platonov; I. V. Vyukhina; A. A. Kachaev; V. M. Sokolov

2008-01-01

132

Paint under pressure  

NASA Astrophysics Data System (ADS)

A class of paints is described which can be employed to indicate the static air pressure being exerted on them, and reference is given to the developmental status of the coatings. The paints are based on the use of 'probe' molecules that fluoresce when excited by distinct light frequencies, and the sensitivities of the paints are described with reference to test results. The coatings can be employed to reduce the costs of wind-tunnel and flight tests by rendering redundant the currently used networks of taps and transducers.

Demeis, Richard

1992-03-01

133

Evaluation of Nodal Reactor Physics Methods for Quasi-Static and Time-Dependent Coupled Neutronic Thermal - Analysis of Pressurized Water Reactor Transients  

NASA Astrophysics Data System (ADS)

This thesis examines coupled time-dependent thermal -hydraulic (T/H) and neutronics solution methods for Pressurized Water Reactor (PWR) transient analysis. The degree of equivalence is evaluated between the typical quasi-static approach and a newly-developed iterative tandem method. Four specific PWR transients that exhibit a wide range of Reactor Coolant System (RCS) T/H response were investigated: (1) a Station Blackout Anticipated Transient Without Scram (ATWS), (2) a Loss of Feedwater ATWS, (3) a Total Loss of RCS Flow with Scram, and (4) a Main Steam Line Break (MSLB). Rather than using simplified RCS and core models, the theory and method in this thesis were applied practically by using realistic models for an actual four-loop Westinghouse PWR plant. The time-dependent STAR kinetics code, based on the QUANDRY Analytic Nodal Method, and the RETRAN and MCPWR T/H systems codes were used to develop a new, fully coupled, tandem STAR/MCPWRQ methodology that runs tandemly on an enhanced 386/387 IBM PC architecture. MCPWRQ uses externally calculated power input rather than point kinetics power level results. The tandem method was compared to quasi -static STAR and time-dependent STAR 2-D and 3-D kinetics results. The new STAR/MCPWRQ method uses RETRAN time-dependent T/H and point kinetics power input as a first estimate. STAR and MCPWRQ are used tandemly to couple STAR 3-D, time-dependent core power results with the MCPWRQ RCS T/H phenomena. This thesis shows that: (a) quasi-static and point kinetics methods are not able to describe severe PWR transient phenomena adequately; and (b) fully coupled, 3-D, time -dependent, tandem (or possibly parallel) analysis methods should be used for PWR reactor transients instead. By tandemly coupling the RCS response in terms of updated core inlet conditions with 3-D time-dependent core kinetics response, the core power response and T/H conditions are forced to be self-consistent during the entire transient. The transient analyses show that a time-dependent, 3-D method is needed when non-equilibrium conditions exist in either the RCS T/H or core neutronic behavior. In general, the quasi-static approach predicts the nodal power distributions incorrectly. Point kinetics and quasi-static methods should be used only after a thermal -hydraulically coupled, time-dependent 3-D neutronics tandem method has been used to validate such simplifying approximations.

Feltus, Madeline Anne

1990-01-01

134

Respiratory monitoring system based on the nasal pressure technique for the analysis of sleep breathing disorders: Reduction of static and dynamic errors, and comparisons with thermistors and pneumotachographs  

NASA Astrophysics Data System (ADS)

Thermally sensitive devices-thermistors-have usually been used to monitor sleep-breathing disorders. However, because of their long time constant, these devices are not able to provide a good characterization of fast events, like hypopneas. Nasal pressure recording technique (NPR) has recently been suggested to quantify airflow during sleep. It is claimed that the short time constants of the devices used to implement this technique would allow an accurate analysis of fast abnormal respiratory events. However, these devices present errors associated with nonlinearities and acoustic resonance that could reduce the diagnostic value of the NPR. Moreover, in spite of the high scientific and clinical potential, there is no detailed description of a complete instrumentation system to implement this promising technique in sleep studies. In this context, the purpose of this work was twofold: (1) describe the development of a flexible NPR device and (2) evaluate the performance of this device when compared to pneumotachographs (PNTs) and thermistors. After the design details are described, the system static accuracy is evaluated by a comparative analysis with a PNT. This analysis revealed a significant reduction (p<0.001) of the static error when system nonlinearities were reduced. The dynamic performance of the NPR system was investigated by frequency response analysis and time constant evaluations and the results showed that the developed device response was as good as PNT and around 100 times faster (?=5,3 ms) than thermistors (?=512 ms). Experimental results obtained in simulated clinical conditions and in a patient are presented as examples, and confirmed the good features achieved in engineering tests. These results are in close agreement with physiological fundamentals, supplying substantial evidence that the improved dynamic and static characteristics of this device can contribute to a more accurate implementation of medical research projects and to improve the diagnoses of sleep-breathing disorders.

Alves de Mesquita, Jayme; Lopes de Melo, Pedro

2004-03-01

135

In situ measurement of magnesium carbonate formation from CO2 using static high-pressure and -temperature 13C NMR.  

PubMed

We explore a new in situ NMR spectroscopy method that possesses the ability to monitor the chemical evolution of supercritical CO(2) in relevant conditions for geological CO(2) sequestration. As a model, we use the fast reaction of the mineral brucite, Mg(OH)(2), with supercritical CO(2) (88 bar) in aqueous conditions at 80 °C. The in situ conversion of CO(2) into metastable and stable carbonates is observed throughout the reaction. After more than 58 h of reaction, the sample was depressurized and analyzed using in situ Raman spectroscopy, where the laser was focused on the undisturbed products through the glass reaction tube. Postreaction, ex situ analysis was performed on the extracted and dried products using Raman spectroscopy, powder X-ray diffraction, and magic-angle spinning (1)H-decoupled (13)C NMR. These separate methods of analysis confirmed a spatial dependence of products, possibly caused by a gradient of reactant availability, pH, and/or a reaction mechanism that involves first forming hydroxy-hydrated (basic, hydrated) carbonates that convert to the end-product, anhydrous magnesite. This carbonation reaction illustrates the importance of static (unmixed) reaction systems at sequestration-like conditions. PMID:22676479

Surface, J Andrew; Skemer, Philip; Hayes, Sophia E; Conradi, Mark S

2012-06-11

136

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

137

Tire pressure monitoring system  

Microsoft Academic Search

In view of the automobile tire security problem, designs the tire pressure monitor system.The hardware system by the pressure transmitter, the micro controller and receives and dispatches RF to be composed, completes the tire pressure and temperature signal gathering, the launch duty through the CAN line transmission; The receiver receive pressure information carries on processing, the driver real-time carries on

Mingsheng Shao; Weixia Guo

2011-01-01

138

Arterial blood pressure and its measurement  

Microsoft Academic Search

Summary Pressure is defined as force per unit area. The actual value of the recorded pressure depends on dynamic influences, like acceleration and friction in a moving fluid, and on static influences like the effect of a gravitational field. In the arterial system, four mechanisms exert the main influence on the measured pressure: (1) cardiac output and peripheral resistance, on

T. Kenner

1988-01-01

139

Your Blood Pressure  

NSDL National Science Digital Library

Keeping your blood pressure at healthy levels is an important factor in preventing cardiovascular disease and stroke. This activity will help you: Understand the categories for blood pressure levels. Know your own blood pressure level Determine ways to prevent hypertension Understand the lifestyle factors that put you at risk for hypertension. Read about blood pressure categories. Read preventing hypertension. Read measuring your blood pressure. Print a copy of the directions on how to use a digital monitor. Check ...

Cross, Mrs.

2005-11-29

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

High pressure tubular swivel joint  

Microsoft Academic Search

A swivel joint and connection for abutting high pressure hydraulic manifolds are described. The joint consists of 2 flanged nonrotating swivel bodies, with one of the nonrotating swivel bodies having a rotating swivel body journaled in it. A flanged tubular sleeve is secured between the adjacent end faces of the 2 nonrotating swivel bodies. A static annular seal is disposed

Kendrick

1976-01-01

142

Infinite Line Pressure Probe.  

National Technical Information Service (NTIS)

The infinite line pressure probe provides a means for measuring high frequency fluctuating pressures in difficult environments. A properly designed infinite line probe does not resonate; thus its frequency response is not limited by acoustic resonance in ...

D. R. Englund W. B. Richards

1984-01-01

143

Vapour Pressure Equations.  

National Technical Information Service (NTIS)

An account is given of the ways in which the relationship between temperature and vapor pressures of single component liquids may be expressed mathematically. Chebyshev polynomials and vapor-pressure measurement was adapted and amplified. The representati...

D. Ambrose

1972-01-01

144

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

145

Preventing pressure ulcers  

MedlinePLUS

Decubitus ulcer prevention; Bedsore prevention; Pressure sores prevention ... care protocol: Skin safety protocol: Risk assessment and prevention of pressure ulcers . Institute for Clinical Systems Improvement. 2nd ed. 2007 ...

146

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

147

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

148

Circumferential Pressure Probe.  

National Technical Information Service (NTIS)

A probe for measuring circumferential pressure inside a body cavity is disclosed. In the preferred embodiment, a urodynamic pressure measurement probe for evaluating human urinary sphincter function is disclosed. Along the length of the probe are disposed...

H. K. Holmes T. C. Moore A. J. Fanti

1988-01-01

149

Fuel Pressure Increase Limiter.  

National Technical Information Service (NTIS)

The invention belongs to the field of the automatic control of turbojet engines, in particular, to fuel pressure increase limiters. Known are fuel pressure increase limiters, predominantly for a turbojet engine, which contain a spring-opposed servopistion...

Y. M. Akhmetov V. I. Bolshagin A. A. Ryzhov V. S. Dyakonov M. A. Medvedeva

1977-01-01

150

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

151

Diffusion Pump Pressure Gauge  

Microsoft Academic Search

A pressure gauge is described suitable for giving a continuous record of residual pressure in an exhausted vessel such as a cyclotron or mercury-arc rectifier. It consists of a diffusion pump discharging back to the fine-pressure side through a throttle, the amplified fine-side pressure being read off on an oil- or bellows-type manometer connected across the throttle. The sensitivity of

J A V Fairbrother; J. A. V

1948-01-01

152

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)

1986-01-01

153

PRESSURE SYSTEM CONTROL  

DOEpatents

The control of pressure in pressurized liquid systems, especially a pressurized liquid reactor system, may be achieved by providing a bias circuit or loop across a closed loop having a flow restriction means in the form of an orifice, a storage tank, and a pump connected in series. The subject invention is advantageously utilized where control of a reactor can be achieved by response to the temperature and pressure of the primary cooling system.

Esselman, W.H.; Kaplan, G.M.

1961-06-20

154

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 fluoresce 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. 10 figs.

Hirschfeld, T.B.

1986-07-15

155

High pressure melt ejection  

Microsoft Academic Search

Recent probabilistic risk assessments have identified the potential for reactor pressure vessel failure while the reactor coolant system is at elevated pressure. The analyses postulate that the blowdown of steam and hydrogen into the reactor cavity will cause the core material to be swept from the cavity region into the containment building. The High Pressure Melt Streaming (HIPS) program is

W. W. Tarbell; J. E. Brockmann; M. Pilch

1983-01-01

156

RHIC PRESSURE RISE.  

SciTech Connect

Beam induced pressure rise remains an intensity limit at RHIC for both heavy ion and polarized proton operations. The pressure rises at beam injection, transition, and rebucketing are discussed, where the beam rebucketing pressure rise is probably of most concern for upcoming runs. Counter measures and results of beam studies are presented.

ZHANG,S.Y.ALESSI,J.BAI,M.BLASKIEWICZ,M.ET AL.

2004-07-05

157

High Pressure Experimental Methods  

Microsoft Academic Search

This book is a worthy addition to the literature on high-pressure techniques. Unlike earlier books, it emphasizes diamond - anvil cells, which are useful in the range from 1 kbar to multi-megabar pressures, while not neglecting the older techniques (piston - cylinder etc) which give much lower maximum pressures but in much larger volumes. The author take a refreshing approach

D J Dunstan

1996-01-01

158

Glucocorticoids and intraocular pressure  

Microsoft Academic Search

The state of intraocular pressure and aqueous humor dynamics as well as histomorphologic and histochemical change of the eye tissues as a result of administration of glucocorticoids were studied in 62 rabbits. After administration of glucocorticoids by instillations and subconjunctival injections there was a trend toward increased intraocular pressure but no statistically significant change in the intraocular pressure was demonstrated.

Valentina M. Pantieleva; Alla M. Shapkina

1976-01-01

159

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

160

The MgSiO3 system at high pressure: Thermodynamic properties of perovskite, postperovskite, and melt from global inversion of shock and static compression data  

Microsoft Academic Search

We present new equation-of-state (EoS) data acquired by shock loading to pressures up to 245 GPa on both low-density samples (MgSiO3 glass) and high-density, polycrystalline aggregates (MgSiO3 perovskite + majorite). The latter samples were synthesized using a large-volume press. Modeling indicates that these materials transform to perovskite, postperovskite, and\\/or melt with increasing pressure on their Hugoniots. We fit our results

Jed L. Mosenfelder; Paul D. Asimow; Daniel J. Frost; David C. Rubie; Thomas J. Ahrens

2009-01-01

161

Fuzzy blood pressure measurement  

NASA Astrophysics Data System (ADS)

In this paper, an intelligent system for blood pressure measurement is posed together with a possible implementation using an eight bit fuzzy processor. The system can automatically determine the ideal cuff inflation level eliminating the discomfort and misreading caused by incorrect cuff inflation. Using statistics distribution of the systolic and diastolic blood pressure, in the inflation phase, a fuzzy rule system determine the pressure levels at which checking the presence of heart beat in order to exceed the systolic pressure with the minimum gap. The heart beats, characterized through pressure variations, are recognized by a fuzzy classifier.

Cuce, Antonino; di Guardo, Mario; Sicurella, Gaetano

1998-10-01

162

Pressure (Or No Royal Road)  

ERIC Educational Resources Information Center

|Discusses how difficult the various problems of pressure, partial pressure, gas laws, and vapor pressure are for students. Outlines the evolution of the concept of pressure, the gas equation for a perfect gas, partial pressures, saturated vapor pressure, Avogadro's hypothesis, Raoult's law, and the vapor pressure of ideal solutions. (JR)|

Bradley, J.

1973-01-01

163

Pressure locking test results  

SciTech Connect

The U.S. Nuclear Regulatory Commission (NRC), Office of Nuclear Regulatory Research, is funding the Idaho National Engineering Laboratory (INEL) in performing research to provide technical input for their use in evaluating responses to Generic Letter 95-07, {open_quotes}Pressure Locking and Thermal Binding of Safety-Related Power-Operated Gate Valves.{close_quotes} Pressure locking and thermal binding are phenomena that make a closed gate valve difficult to open. This paper discusses only the pressure locking phenomenon in a flexible-wedge gate valve; we will publish the results of our thermal binding research at a later date. Pressure locking can occur when operating sequences or temperature changes cause the pressure of the fluid in the bonnet (and, in most valves, between the discs) to be higher than the pressure on the upstream and downstream sides of the disc assembly. This high fluid pressure presses the discs against both seats, making the disc assembly harder to unseat than anticipated by the typical design calculations, which generally consider friction at only one of the two disc/seat interfaces. The high pressure of the bonnet fluid also changes the pressure distribution around the disc in a way that can further contribute to the unseating load. If the combined loads associated with pressure locking are very high, the actuator might not have the capacity to open the valve. The results of the NRC/INEL research discussed in this paper show that the relationship between bonnet pressure and pressure locking stem loads appears linear. The results also show that for this valve, seat leakage affects the bonnet pressurization rate when the valve is subjected to thermally induced pressure locking conditions.

DeWall, K.G.; Watkins, J.C.; McKellar, M.G.; Bramwell, D.

1996-06-01

164

49 CFR 178.814 - Hydrostatic pressure test.  

Code of Federal Regulations, 2011 CFR

...the 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 filled...the 65 kPa (9.4 psig) test pressure specified in paragraph...

2011-10-01

165

49 CFR 178.814 - Hydrostatic pressure test.  

Code of Federal Regulations, 2012 CFR

...the 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 filled...the 65 kPa (9.4 psig) test pressure specified in paragraph...

2012-10-01

166

Bag pressure monitor  

DOEpatents

An inexpensive mechanical indicator for measuring low pressure in an inflating bag includes a pair of sides connected to each other at one edge and pivotally connected at spaced parallel locations on the bag. A spring biases the sides towards each other in opposition to tension in the inflating bag. The distance between the sides is indicative of the pressure in the bag. The device is accurate at pressures below 0.05 psi.

Vaughn, Mark Roy (Albuquerque, NM); Miller, Alva Keith (Albuquerque, NM)

2000-01-01

167

Pressurized burner test facility  

Microsoft Academic Search

The US Department of Energy`s METC has recently completed construction and commissioning of a new high-pressure combustion research facility. Utilities servicing the facility enable combustion tests at scales up to 3 MW (10 MM Btu\\/h) and pressures in excess of 3000 kPa (30 atm). These include a preheated, high-pressure air supply that can deliver up to 1.7 kg\\/s (3.7 lbs\\/s)

D. J. Maloney; T. S. Norton; M. A. Hadley

1993-01-01

168

Political pressure deflection  

Microsoft Academic Search

Much economic policy is deliberately shifted away from direct political processes to administrative processes—political pressure\\u000a deflection. Pressure deflection poses a puzzle to standard political economy models which suggest that having policies to\\u000a ‘sell’ is valuable to politicians. The puzzle is solved here by showing that incumbents will favor pressure deflection since\\u000a it can deter viability of a challenger, essentially like

James E. Anderson; Maurizio Zanardi

2009-01-01

169

Pressure cryocooling protein crystals  

SciTech Connect

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

170

Eclogites and water pressure  

Microsoft Academic Search

Available data on the stability of amphibolites and the basalt-eclogite transition allow an estimate of the stability field\\u000a of eclogites in wet systems. It appears that if water and load pressures are comparable, eclogites cannot be stable in the\\u000a crust; the formation of eclogites in the crust requires moderate total pressures and low water pressures. If the reactions\\u000a forming eclogites

N. Fry; W. S. Fyfe

1969-01-01

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. 1 fig.

Isaksson, J.

1996-03-19

172

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, T.B.

1982-09-30

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

Electrolytic pressure transduction system  

NASA Astrophysics Data System (ADS)

This invention is directed to a Wheatstone bridge circuit for measuring pressure in the distal esophageal sphincter (D.E.S.) as well as in other organs and bodily cavities. A flexible hollow tube having three spaced electrodes is lodged in the esophagus. The tube is partly filled with a saline solution to cover the electrodes, thereby producing two series connected, pressure sensitive resistors. The electrolytic resistors are coupled to two series connected fixed resistors to complete the bridge circuit. Electrical imbalances in the bridge circuit are measured in terms of the pressure corresponding to the pressure applied by the D.E.S.

Bryant, G. H.

1985-12-01

175

Sapphire tube pressure vessel  

SciTech Connect

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, J.O.

2000-05-23

176

Pressure sintering of powder materials  

Microsoft Academic Search

Rheological models for pressure sintering of powder materials are described. The rheological models of deformable bodies and\\u000a the associated dynamic deformation theory for porous bodies based on the energy conservation law enable a quantitative description\\u000a of their densification under impulse and static hot pressing as well as hot forging using crank presses. The simulation of\\u000a compaction of porous metals shows

M. S. Kovalchenko

2011-01-01

177

Pressure Probe for Safety-Arming Device.  

National Technical Information Service (NTIS)

An air pressure sensing probe is disclosed for providing static-dynamic differential air pressure to operate a guided missile warhead safety-arming device. The probe assembly is hermetically sealed to keep the device free of dirt and moisture during stora...

L. F. Brauer J. O. Eaton

1978-01-01

178

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

179

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

NASA Astrophysics Data System (ADS)

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 applicable to other high-pressure spectroscopic cells. The flow-cell design has a minimal sample dead volume, which is important for kinetic studies. The design eliminates the need for brazing or for a soft-sealing material for the optical windows, thereby minimizing the number of materials in contact with the sample. Using only diamond and platinum or platinum alloys as the corrosion resistant materials, the design is optimized for the study of aqueous solutions at high temperatures. Infrared spectra of an aqueous sodium tungstate solution up to 400 °C and 380 bar pressure are presented. Time-resolved infrared data are also presented for the ultraviolet photolysis reaction of ?-naphthoyl azide in supercritical carbon dioxide.

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

2000-03-01

180

Winds and Pressure  

NSDL National Science Digital Library

This undergraduate meteorology tutorial discusses the different ways that the air responds to pressure gradients on a small scale and on a large scale, defines and explains geostrophic balance, and describes how to infer the large-scale wind pattern from maps of pressure or height.

Nielsen-Gammon, John

1996-01-01

181

Differential pressure sensor  

Microsoft Academic Search

A pressure sensor for use in sea mine applications is presented. The sensor detects the presence of a passing vessel by sensing a change in ambient water pressure caused by the hydrodynamic flow induced by the vessel's motion (Bernoulli effect). The sensor emits a responsive signal which can be used alone, or with signals from other influence sensors (acoustic and

Charles A. Rowzee; John D. Sherman

1991-01-01

182

Pressurized burner test facility.  

National Technical Information Service (NTIS)

The US Department of Energy's METC has recently completed construction and commissioning of a new high-pressure combustion research facility. Utilities servicing the facility enable combustion tests at scales up to 3 MW (10 MM Btu/h) and pressures in exce...

D. J. Maloney T. S. Norton M. A. Hadley

1993-01-01

183

Reduce the pressure.  

PubMed

Pressure ulcers are increasingly viewed as a measure of patient harm, preventable by good nursing practice. NHS Midlands and East has an ambitious target of eliminating avoidable grade two, three and four pressure ulcers by the end of the year. Nurses and managers have responded enthusiastically to the challenge, with some organisations achieving dramatic improvements. PMID:23240511

Moore, Alison

184

Gas Laws: Pressure  

NSDL National Science Digital Library

This site offers an interactive tutorial in which students are taken thrugh three exercises: reading a manometer, measuring pressure when the manometer contains a liquid other than water, compensating for the vapor pressure of a volatile liquid in the manometer. This tutorial is coupled to others to further guide the student to a better understanding of the principles which govern the behavior of gases.

Blauch, David N.

185

Pressure Sensitive Regulation Valve.  

National Technical Information Service (NTIS)

The patent application relates to a pressure sensitive regulating valve formed of a spring mounted within a conduit in which fluid flow is to be regulated. The fluid flow is regulated by the pressure responsive expansion and contraction of the axially def...

E. A. Gallo

1975-01-01

186

PRESTRESSED CONCRETE PRESSURE VESSELS  

Microsoft Academic Search

The pros and cons of using prestressed concrete pressure vessels, based ; on observations of model tests, for the next British nuclear power station are ; reviewed. The characteristics, present development, and design methods are ; considered. The results indicate that the prestressed concrete pressure vessel ; is more practicable, safe, and economical than the steel vessel. (N.W.R.)

S. Gill; I. W. Hannah

1962-01-01

187

Diaphragm Pressure Transducer  

Microsoft Academic Search

A diaphragm pressure transducer has been developed for the purpose of separating a sample fluid from a hydraulic oil used in a dead weight tester. The diaphragm null position is determined by a commercially available magnetic sensing unit. The null position shifts systematically with absolute pressure, but the shift is reproducible and may be calibrated. With the output scheme utilized,

W. I. HONEYWELLt; C. J. Pings

1965-01-01

188

Polarity and Vapour Pressure  

Microsoft Academic Search

IN considering the effect of polarity on the vapour pressure and association of a liquid, a simple case is its influence on the partial vapour pressures of a polar liquid in its binary mixtures with a non-polar liquid, which, except for lack of polarity, should preferably be closely related in chemical structure to the polar liquid.

A. R. Martin

1931-01-01

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

Endobronchial cuff pressures.  

PubMed

In 20 adult patients (18 male) who presented for thoracotomy, the trachea was intubated using Mallinckrodt disposable double-lumen tubes (18 large and two medium). The endobronchial cuff was inflated by a trained operating department assistant using an air-filled syringe. The volume of air and the initial endobronchial cuff pressure were measured. The minimum cuff pressure required to prevent respiratory gas leakage from the isolated lung was measured also and maintained using the Cardiff Cuff Controller. Mean initial cuff pressure was 69.3 (SEM 6.0) mm Hg, whereas the mean minimum cuff pressure was 29.5 (4.0) mm Hg (P < 0.0001). The results suggest that the method described of inflating the endobronchial cuff may lead to overinflation and subsequent excessive pressure on the endobronchial wall. PMID:8318334

Cobley, M; Kidd, J F; Willis, B A; Vaughan, R S

1993-05-01

191

Design and development of diaphragm-based EFPI pressure sensor  

NASA Astrophysics Data System (ADS)

An extrinsic fabry-perot interferometric pressure sensor is fabricated using a cavity formed by a metal diaphragm and a single mode optical fiber. The compact sensor probe has been tested for static pressure response using diaphragms of different metals.

Anish, P. P.; Linesh, J.; Libish, T. M.; Mathew, S.; Radhakrishnan, P.

2010-12-01

192

33 CFR 183.586 - Pressure impulse test.  

Code of Federal Regulations, 2013 CFR

...Navigation and Navigable Waters 2 2013-07-01...2013-07-01 false Pressure impulse test. 183...Navigation and Navigable Waters COAST GUARD, DEPARTMENT...air, inert gas, or water. (g) Perform the static pressure test under §...

2013-07-01

193

Cavitation pressure in liquid helium  

NASA Astrophysics Data System (ADS)

Recent experiments have suggested that, at low enough temperature, the homogeneous nucleation of bubbles occurs in liquid helium near the calculated spinodal limit. This was done in pure superfluid helium 4 and in pure normal liquid helium 3. However, in such experiments, where the negative pressure is produced by focusing an acoustic wave in the bulk liquid, the local amplitude of the instantaneous pressure or density is not directly measurable. In this article, we present a series of measurements as a function of the static pressure in the experimental cell. They allowed us to obtain an upper bound for the cavitation pressure Pcav (at low temperature, Pcav<-2.4 bar in helium 3, Pcav<-8.0 bar in helium 4). From a more precise study of the acoustic transducer characteristics, we also obtained a lower bound (at low temperature, Pcav>-3.0 bar in helium 3, Pcav>-10.4 bar in helium 4). In this article we thus present quantitative evidence that cavitation occurs at low temperature near the calculated spinodal limit (-3.1 bar in helium 3 and -9.5 bar in helium 4). Further information is also obtained on the comparison between the two helium isotopes. We finally discuss the magnitude of nonlinear effects in the focusing of a sound wave in liquid helium, where the pressure dependence of the compressibility is large.

Caupin, F.; Balibar, S.

2001-08-01

194

Hydrostatic pressure mimics gravitational pressure in characean cells  

Microsoft Academic Search

Summary Hydrostatic pressure applied to one end of a horizontalChara cell induces a polarity of cytoplasmic streaming, thus mimicking the effect of gravity. A positive hydrostatic pressure induces a more rapid streaming away from the applied pressure and a slower streaming toward the applied pressure. In contrast, a negative pressure induces a more rapid streaming toward and a slower streaming

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

1992-01-01

195

A flexible pressure monitoring system for pressure ulcer prevention  

Microsoft Academic Search

Pressure ulcers are painful sores that arise from prolonged exposure to high pressure points, which restricts blood flow and leads to tissue necrosis. This is a common occurrence among patients with impaired mobility, diabetics and the elderly. In this work, a flexible pressure monitoring system for pressure ulcer prevention has been developed. The prototype consists of 99 capacitive pressure sensors

Marcus Yip; David Da He; Eric Winokur; Amanda Gaudreau Balderrama; Robert Sheridan; Hongshen Ma

2009-01-01

196

Starch gelatinization under pressure studied by high pressure DSC  

Microsoft Academic Search

The gelatinization process of waxy corn starch under different pressures up to 10.0MPa was investigated using a high pressure DSC. Compressed air and carbon dioxide were used as pressure resources. Effect of pressure and annealing under pressure on gelatinization of waxy corn starch was systematically studied, in particular on the gelatinization temperature and enthalpy. The results show that the peak

Hongsheng Liu; Long Yu; Katherine Dean; George Simon; Eustathios Petinakis; Ling Chen

2009-01-01

197

Pressure Measurement Systems  

NASA Astrophysics Data System (ADS)

System 8400 is an advanced system for measurement of gas and liquid pressure, along with a variety of other parameters, including voltage, frequency and digital inputs. System 8400 offers exceptionally high speed data acquisition through parallel processing, and its modular design allows expansion from a relatively inexpensive entry level system by the addition of modular Input Units that can be installed or removed in minutes. Douglas Juanarena was on the team of engineers that developed a new technology known as ESP (electronically scanned pressure). The Langley ESP measurement system was based on miniature integrated circuit pressure-sensing transducers that communicated pressure information to a minicomputer. In 1977, Juanarena formed PSI to exploit the NASA technology. In 1978 he left Langley, obtained a NASA license for the technology, introduced the first commercial product, the 780B pressure measurement system. PSI developed a pressure scanner for automation of industrial processes. Now in its second design generation, the DPT-6400 is capable of making 2,000 measurements a second and has 64 channels by addition of slave units. New system 8400 represents PSI's bid to further exploit the 600 million U.S. industrial pressure measurement market. It is geared to provide a turnkey solution to physical measurement.

1990-01-01

198

Pressurizer tank upper support  

DOEpatents

A pressurizer tank in a pressurized water nuclear reactor is mounted between structural walls of the reactor on a substructure of the reactor, the tank extending upwardly from the substructure. For bearing lateral loads such as seismic shocks, a girder substantially encircles the pressurizer tank at a space above the substructure and is coupled to the structural walls via opposed sway struts. Each sway strut is attached at one end to the girder and at an opposite end to one of the structural walls, and the sway struts are oriented substantially horizontally in pairs aligned substantially along tangents to the wall of the circular tank. Preferably, eight sway struts attach to the girder at 90[degree] intervals. A compartment encloses the pressurizer tank and forms the structural wall. The sway struts attach to corners of the compartment for maximum stiffness and load bearing capacity. A valve support frame carrying the relief/discharge piping and valves of an automatic depressurization arrangement is fixed to the girder, whereby lateral loads on the relief/discharge piping are coupled directly to the compartment rather than through any portion of the pressurizer tank. Thermal insulation for the valve support frame prevents thermal loading of the piping and valves. The girder is shimmed to define a gap for reducing thermal transfer, and the girder is free to move vertically relative to the compartment walls, for accommodating dimensional variation of the pressurizer tank with changes in temperature and pressure. 10 figures.

Baker, T.H.; Ott, H.L.

1994-01-11

199

Variable pressure recovery  

SciTech Connect

Control valves have been classified into two broad categories according to the nature of the pressure recovery inside the valve: low recovery valves (typically globe style) and high recovery valves (typically rotary style). This relates to the difference between the lowest absolute pressure at the vena contracta in the valve and the downstream pressure in ratio to the actual pressure drop across the valve. With some new developments in rotary control valves this classification has become insufficient and a new concept variable recovery - needs to be brought into wide usage to be able to evaluate the performance of these designs. In a global style control valve, the pressure recovery is fairly constant throughout the valve opening range. The liquid pressure recovery factor, F/sub L/, can be used as an indicator of how low the pressure recovery in the specific valve is, so that high F/sub L/ factors indicate low recovery and vice versa. Globe valve F/sub L/ range between 0.7 and 0.9 for standard designs depending on the valve style, and stay constant at all valve openings when we use the flow-to-open configuration. Globe valves are typically labeled low recovery. On the other hand, the rotary style valves have, for example, an F/sub L/ factor of 0.55 at full (90/sup 0/) opening for a ball valve and 0.65 at 70/sup 0/ opening for a butterfly valve. These valves typically have been considered high recovery.

Husu, M. (Neles Inc., Glens Falls, NY (US))

1988-09-01

200

Respiratory monitoring system based on the nasal pressure technique for the analysis of sleep breathing disorders: Reduction of static and dynamic errors, and comparisons with thermistors and pneumotachographs  

Microsoft Academic Search

Thermally sensitive devices-thermistors-have usually been used to monitor sleep-breathing disorders. However, because of their long time constant, these devices are not able to provide a good characterization of fast events, like hypopneas. Nasal pressure recording technique (NPR) has recently been suggested to quantify airflow during sleep. It is claimed that the short time constants of the devices used to implement

Jayme Alves de Mesquita; Pedro Lopes de Melo

2004-01-01

201

Respiratory monitoring system based on the nasal pressure technique for the analysis of sleep breathing disorders: Reduction of static and dynamic errors, and comparisons with thermistors and pneumotachographs  

Microsoft Academic Search

Thermally sensitive devices—thermistors—have usually been used to monitor sleep-breathing disorders. However, because of their long time constant, these devices are not able to provide a good characterization of fast events, like hypopneas. Nasal pressure recording technique (NPR) has recently been suggested to quantify airflow during sleep. It is claimed that the short time constants of the devices used to implement

Jayme Alves de Mesquita; Pedro Lopes de Melo

2004-01-01

202

Metal-doped (Ti, WC) diamond-like-carbon coatings: Reactions with extreme-pressure oil additives under tribological and static conditions  

Microsoft Academic Search

In contrast to non-doped diamond-like-carbon (DLC) coatings, reliable chemical evidence of the reactions between metal-doped DLC coatings and oil additives under tribological conditions using state-of-the-art surface-sensitive chemical analyses is still scarce. In this study we have investigated the reactivity of metal-doped (Ti, WC) DLC coatings with the extreme-pressure (EP) dialkyl dithiophosphate additive — without the presence of a steel counter

M. Kalin; E. Roman; L. Ožbolt; J. Vižintin

2010-01-01

203

Tyre Pressure Monitoring Microsystems  

Microsoft Academic Search

\\u000a The need for monitoring the pressure and temperature of an automotive tire is increasing, and this paper will describe SensoNors\\u000a products and philosophy that aim to meet these demands in the future.\\u000a \\u000a \\u000a SensoNor has designed a range of tyre pressure sensors to meet the different demands from the market. These designs are all\\u000a based on SensoNors platform for pressure sensors,

R. Grelland

204

A micromachined pressure sensor for biomedical applications  

NASA Astrophysics Data System (ADS)

A silicon pressure microsensor fabrication process is reported. The microsensor has been designed as a low-cost disposable device for invasive blood pressure measurements. Results obtained from static, dynamic and leakage pressure tests are presented. A sensitivity of 0960-1317/7/3/044/img11 has been measured. The combined linearity and hysteresis is less than 1.5% FSO. The dynamic response is fast enough to reproduce the blood pressure waveform of the human heart. Results based on a material biocompatibility study are also included.

Bistué, G.; Elizalde, J.; García-Alonso, I.; Olaizola, S.; Castaño, E.; Gracia, F. J.; García-Alonso, A.

1997-09-01

205

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

206

Pressure Versus Depth  

NSDL National Science Digital Library

In this inquiry activity, students do not know the equation for pressure versus depth before beginning, but through guided activities they discover it themselves. This is a powerful way to get students to conceptually understand the equation and remember

Horton, Michael

2009-05-30

207

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

208

Pressure Garment Subsystem Roadmap.  

National Technical Information Service (NTIS)

The Constellation program pressure garment subsystem (PGS) team has created a technical roadmap that communicates major technical questions and how and when the questions are being answered in support of major project milestones. The roadmap is a living d...

A. J. Ross

2010-01-01

209

Analog Pressure Transducer.  

National Technical Information Service (NTIS)

The report describes the results of a comprehensive study to design, fabricate and test an analog resistance readout pressure transducer for dropsonde application. A laboratory model was built and tested, with results generally within the plus or minus 2-...

T. A. Broun

1973-01-01

210

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

211

The Pressure's On  

NSDL National Science Digital Library

If the pressure's on to enhance the growth and development of students' inquiry skills, use a discrepant event. A discrepant event is a demonstration designed to present a situation or phenomenon that has an unexpected and sometimes very surprising outcom

Jr., Frank L.

2000-09-01

212

[Preventing pressure ulcers].  

PubMed

Preventing the occurrence of pressure ulcers requires multi-disciplinary care of the patient. Firstly, it is necessary to identify patients predisposed to developing pressure ulcers thanks to awareness of the risk factors and using where necessary adapted assessment scales. Preventative measures then comprise the suitable positioning of the patient, regularly changing their position, the use of special support equipment, nursing care and the treatment of undernutrition. PMID:23785858

Néouze, Angèle

213

Pressure multiplying dispenser  

DOEpatents

A pressure multiplying dispenser for delivering fluid, preferably as a spray to the atmosphere, from a source of fluid, preferably a spray bottle, is described. The dispenser includes in combination a hollow cylindrical member, a nozzle delivery tube within the cylindrical member and a hollow actuator piston slideable within the cylindrical member which acts to multiply the pressure of a squeeze applied to the spray bottle.

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

1986-01-01

214

Pressure fluctuating tool  

SciTech Connect

The Pressure Fluctuating Tool (PFT) utilizes a fluidic oscillator to create pulsating pressure for breaking down perforations. The maximum pressure fluctuations produced by the oscillator can be as great as 1500 psi (10,300 kPa) above and below downhole ambient pressure with frequency ranging from 140 to 160 cycles per second. Pressure fluctuations are greatest in the primary oscillation zone located at the center of the 26 foot (7.92m) long tool. The pressure fluctuations decrease to essentially zero within 8 feet (2.43m) above and 8 feet (2.43m) below the primary oscillation zone. These fluctuations break down the perforations and formation face. As perforations are opened, the casing annulus is effectively exposed to a larger fluid volume, causing the amplitude and frequency of fluctuations to decrease. These changes are monitored by instrumentation at the surface to determine when breakdown is complete and the tool can be moved to the next section of perforations. This paper describes the operation of the PFT and reports data collected in field applications.

Payne, R.A.; Bailey, H.L.; Pelty, L.L.; Williams, K.A.

1985-03-01

215

ECN Pressure Test  

SciTech Connect

This note describes: the rationale for the test pressure of the inner ECN cryostat vessel, the equipment to be used in this test, the test procedure, the status of the vessel prior to the test, the actual test results, and a schematic diagram of the testing set up and the pressure testing permit. The test, performed in the evening of July 17, 1991, was a major success. Based on a neglible pressure drop indicated on the pressure gages (1/4 psi), the vessel appeared to be structurally sound throughout the duration of the test (approx. 1.5 hrs.). No pressure increases were observed on the indicators looking at the beam tube bellows volumes. There was no indication of bubbles form the soap test on the welds and most of the fittings that were checked. There were some slight deviations in the actual procedure used. The UO filter was removed after the vessel had bled down to about 18 psig in order to speed up that aspect of the test. The rationale was that the higher velocity gas had already passed through at the higher pressures and there was no visible traces of the black uo particles. The rate of 4 psi/10 minutes seemed incredibly slow and often that time was reduced to just over half that rate. The testing personnel was allowed to stay in the pit throughout the duration of the test; this was a slight relaxation of the rules.

Dixon, K.; /Fermilab

1991-07-18

216

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

217

Inspiratory muscle adaptations following pressure or flow training in humans.  

PubMed

Skeletal muscle adapts differently to training with high forces or with high velocities. The effects of these disparate training protocols on the inspiratory muscles were investigated in ten healthy volunteers. Five subjects trained using high force (pressure) loads (pressure trainers) and five trained using high velocity (flow) loads (flow trainers). Pressure training entailed performing 30 maximal static inspiratory efforts against a closed airway. Flow training entailed performing 30 sets of three maximal dynamic inspiratory efforts against a minimal resistance. Training was supervised and carried out 5 days a week for 6 weeks. Inspiratory flow rates and oesophageal pressure-time curves were measured before and after training. Peak inspiratory pressures during maximal static and dynamic efforts and peak flows during the maximal dynamic efforts were calculated. The time-to-peak pressure and rate of rise in peak pressure during maximal static and dynamic manoeuvres were also calculated before and following training. Maximal static pressure increased in the pressure training group and maximal dynamic pressure increased in the flow training group. Both groups increased the rate of pressure production (dP/dt) during their respective maximal efforts. The post-training decrease in time-to-peak pressure was proportionately greater in the flow trainers than in the pressure trainers. The differences in time-to-peak pressure between the two groups were consistent with the different effects of force and velocity training on the time-to-peak tension of skeletal muscle. PMID:10344453

Tzelepis, G E; Kasas, V; McCool, F D

1999-05-01

218

Solid State Gas Pressure Sensor.  

National Technical Information Service (NTIS)

The present invention relates to pressure sensors, and more, particularly, to thermoconductive vacuum pressure sensors. Thermoconductive vacuum transducers (sensors) measure pressure by monitoring the temperature of a heated wire filament in the transduce...

J. Halvis

1987-01-01

219

High Blood Pressure in Pregnancy  

MedlinePLUS

... and your baby. Treatments for high blood pressure in pregnancy may include close monitoring of the baby, ... blood pressure develop preeclampsia. It's a sudden increase in blood pressure after the 20th week of pregnancy. ...

220

Amorphous Materials at High Pressure  

NASA Astrophysics Data System (ADS)

This chapter reviews the different pathways towards high-pressure amorphization, how high-pressure amorphs may be characterized and what are the potential mechanisms causing pressure-induced amorphization and amorphous-amorphous transitions.

Sanloup, Chrystele

221

Optically interrogated MEMS pressure sensor array  

NASA Astrophysics Data System (ADS)

A novel pressure measurement technique is presented for wireless recording of time-averaged surface pressure distributions in wind tunnel surveys. An array of silicon micro-plate resonators acts as pressure sensing element. The pressure is recorded by measuring the sensor diaphragms' resonance frequency using optical interferometry. Dependent on the quasi-static deflection caused by a pressure load, the resonance frequency varies with an average pressure sensitivity of 3 Hz/Pa in a frequency range between 30 and 150 kHz. A smart-pixel CMOS camera, narrow-band acoustic noise excitation and a specific sensor surface structure allow for the interrogation of a large number of sensors in parallel without the need for alignment between sensor and detector. Experimental tests reveal increased sensing performance with acoustic excitation of the higher vibration modes.

Prochazka, Lukas; Meier, Alexander H.; Viggiani, Antonio; Roesgen, Thomas

2012-04-01

222

Monitoring of velocity and pressure fields within an axial turbine  

NASA Astrophysics Data System (ADS)

In the framework of the consortium of R&D on hydraulic machines launched by the LAMH (Hydraulic Machines Laboratory of Laval University) in November 2007, a five holes unsteady pressure probe using embedded pressure sensors has been developed. Such probe allows us to obtain the unsteady static pressure, total pressure and the three flow velocity components. This paper aims to present this new five holes unsteady pressure probe, used and results for a propeller turbine.

Duquesne, P.; Iliescu, M.; Fraser, R.; Deschênes, C.; Ciocan, G. D.

2010-08-01

223

Clutch pressure control apparatus  

SciTech Connect

A clutch pressure control apparatus is described which comprises: (a) a first function generator for generating a clutch pressure control signal in accordance with a first function such that a clutch pressure control signal P/sub c1/ is definitely determined as a function of an engine rotational speed signal and an accelerator pedal stroke signal; (b) a controller including a second function generator for providing a second clutch pressure control signal P/sub c2/ in accordance with a second function such that when actual engine speed at an initial clutch engagement phase at which a clutch is entering a half-clutch state exceeds a predetermined engine speed limit, which does not provide shock when the clutch is engaged, the second clutch pressure control signal is first set to a temporary low value corresponding to an engine speed not exceeding the predetermined engine speed limit and then in accordance with the second function is allowed to approach a value determined by the first function according to the actual engine speed signal; and (c) a start switch for detecting accelerator pedal stroke and transmission shift position and outputting a start signal to start to operate the controller when transmission is shifted to a running position and the accelerator stroke meets a condition for start.

Koori, Y.; Mitsui, T.

1989-01-24

224

Passive blast pressure sensor  

DOEpatents

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

225

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

226

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

227

High Blood Pressure  

NSDL National Science Digital Library

The Science Inside: High Blood PressureThis booklet explains what health professionals know about high blood pressure or hypertension, one of the leading causes of heart disease and stroke. It shows how to prevent high blood pressure, as well as how to care for yourself if you have been diagnosed with the disease. The Science Inside e-book series is intended to be a bridge between the consumer health brochure and the scientific paper, the booklets in this series focus on the science that is inside of, or behind, the disease its cause, its possible cure, its treatment, promising research, and so on. These booklets are designed to appeal to people who have not had the opportunity to study the science and to understand why they may have been given some of the advice that they have been given through some of the more consumer-oriented materials.

American Association for the Advancement of Science (;)

2004-01-01

228

Circumferential pressure probe  

NASA Astrophysics Data System (ADS)

A probe for measuring circumferential pressure inside a body cavity is disclosed. In the preferred embodiment, a urodynamic pressure measurement probe for evaluating human urinary sphincter function is disclosed. Along the length of the probe are disposed a multiplicity of deformable wall sensors which typically comprise support tube sections with flexible side wall areas. These are arranged along the length of the probe in two areas, one just proximal to the tip for the sensing of fluid pressure inside the bladder, and five in the sensing section which is positioned within the urethra at the point at which the urinary sphincter constricts to control the flow of urine. The remainder of the length of the probe comprises multiple rigid support tube sections interspersed with flexible support tube sections in the form of bellows to provide flexibility.

Holmes, Harlan K.; Moore, Thomas C.; Fantl, Andrew J.

1989-10-01

229

PRESSURE SENSING DEVICE  

DOEpatents

This device is primarily useful as a switch which is selectively operable to actuate in response to either absolute or differential predetermined pressures. The device generally comprises a pressure-tight housing divided by a movable impermeable diaphragm into two chambers, a reference pressure chamber and a bulb chamber containing the switching means and otherwise filled with an incompressible non-conducting fluid. The switch means comprises a normally collapsed bulb having an electrically conductive outer surface and a vent tube leading to the housing exterior. The normally collapsed bulb is disposed such that upon its inflation, respensive to air inflow from the vent, two contacts fixed within the bulb chamber are adapted to be electrically shorted by the conducting outer surface of the bulb.

Pope, K.E.

1959-12-15

230

Pressure settling of mesophase  

SciTech Connect

This patent describes a process for producing mesophase pitch wherein a heavy aromatic hydrocarbon feedstock is heat soaked at a first pressure until a substantial portion of the feedstock has been converted to optically anisotropic material, and in which mesophase pitch is recovered from the heat soaked material by gravity settling, the improvement comprises: subjecting and maintaining for a time of up to about 15 minutes the heat soaked material, prior to recovery of mesophase pitch therefrom, to a second pressure which is at least 30 kPa higher than the first pressure for a time of up to about 15 minutes, whereby boiling of the heat soaked material is reduced and settling of mesophase pitch is enhanced.

Romine, H.E.

1989-05-23

231

Low pressure gas regulator  

SciTech Connect

This patent describes a low pressure gas regulator. It comprises: a body member, an inlet opening formed in the body member, an outlet opening formed in the body member, a partition in the body member which separates the inlet and outlet opening and formed with an opening which is surrounded with a valve seat, a moveable diaphragm mounted in the body member so as to have atmospheric pressure on one side thereof and the pressure of the outlet opening on the other side, a valve stem connected to the diaphragm and extending through the opening in the partition, a ball valve mounted on the valve stem in the inlet opening, and a relatively thick soft resilient cover mounted over the ball valve and engageable with the valve seat. Wherein the cover has a first thicker portion which engages the valve seat and a second portion which does not engage the valve seat which is thinner than the first portion.

Wallace, E.E.

1990-02-06

232

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

233

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

234

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

235

Wellbore pressure transducer  

DOEpatents

Subterranean earth formations containing energy values are subjected to hydraulic fracturing procedures to enhance the recovery of the energy values. These fractures are induced in the earth formation by pumping liquid into the wellbore penetrating the earth formation until the pressure of the liquid is sufficient to fracture the earth formation adjacent to the wellbore. The present invention is directed to a transducer which is positionable within the wellbore to generate a signal indicative of the fracture initiation useful for providing a timing signal to equipment for seismic mapping of the fracture as it occurs and for providing a measurement of the pressure at which the fracture is initiated.

Shuck, Lowell Z. (Morgantown, WV)

1979-01-01

236

Plating under reduced pressure  

SciTech Connect

Plating under reduced pressure was evaluated for both electroless nickel and electrodeposited copper systems. The objective was to reduce pitting of these coatings thereby further enhancing their usage for diamond turning applications. Cursory experiments with electroless nickel showed reduced porosity when deposition was done at around 500 torr. Detailed experiments with electrodeposited copper at around 100 torr provided similar results. Scanning tunneling microscopy was effectively used to show the improvement in the copper deposits plated under reduced pressure. Benefits included reduced surface roughness and finer and denser grain structure.

Dini, J.W.; Beat, T.G.; Cowden, W.C. [Lawrence Livermore National Lab., CA (United States); Ryan, L.E.; Hewitt, W.B. [TRW, Inc., Redondo Beach, CA (United States)

1992-06-01

237

Mechanical Behavior of Explosives at High Pressures  

Microsoft Academic Search

The mechanical and ignition behaviors of heterogeneous explosives and pure polymeric binders used in plastic-bonded explosive are highly dependent on the pressure. New apparatus capable of testing small explosive samples under pressures reaching 10 kbar were developed. Unlike previous designs that use a cylinder-piston arrangement, here the samples are quasi-statically and dynamically compacted in a working fluid, thus ensuring isotropic

John Kelley; Vasant Joshi; Raafat Guirguis

2001-01-01

238

Pressure and stress analysis for an underwater vehicle  

Microsoft Academic Search

Underwater vehicles are widely used in both military and civilian operations for more than 60 years. They are the best tools to perform dull, dangerous and dirty tasks in the water. So the distribution principles of static pressure and stress along the vehicle hull must be found out when designing hull shape and choosing the materials. The static pressure and

Yanhui Ai

2011-01-01

239

Negative pressure device for intra-abdominal pressure reduction  

Microsoft Academic Search

A device that generates negative extra-abdominal pressure (ABDOPRE) for treatment of patients with high intra-abdominal pressure was developed. It includes pressure sensors for transducing intra-abdominal pressure through an intra-vesical catheter and negative pressure in the vacuum bell which is placed over the abdomen. By means of a control system, a pattern for reducing IAP is set, according to a clinical

M. David; D. Geido; F. Pracca; G. Sánchez; F. Simini; C. Zoppolo

2007-01-01

240

Barometric pressure variations  

Microsoft Academic Search

This report presents Hanford Site barometric data that can be used to determine the breathing rate of Hanford Site tanks and details the derivation of the data. The barometric pressure data recorded at the Hanford Weather Station were used for this analysis. Data for 1988, 1989, 1990, and 1991 were used.

Crippen

1993-01-01

241

Barometric pressure variations  

SciTech Connect

This report presents Hanford Site barometric data that can be used to determine the breathing rate of Hanford Site tanks and details the derivation of the data. The barometric pressure data recorded at the Hanford Weather Station were used for this analysis. Data for 1988, 1989, 1990, and 1991 were used.

Crippen, M.D.

1993-06-01

242

PeerPressure  

Microsoft Academic Search

Technical support contributes 17% of the total cost of ownership of today's desktop PCs (25). An important element of technical support is troubleshooting misconfigured applications. Misconfiguration troubleshoot- ing is particularly challenging, because configuration in- formation is shared and altered by multiple applications. In this paper, we present a novel troubleshooting system: PeerPressure, which uses statistics from a set of sample

Helen J. Wang; John C. Platt; Yu Chen; Ruyun Zhang; Yi-Min Wang

243

Optimisation of compound pressure  

Microsoft Academic Search

Purpose: The purpose of this paper is optimization of the weight of compound cylinder for a specific pressure. The variables are shrinkage radius and shrinkage tolerance. Design\\/methodology\\/approach: SEQ technique for optimization, the finite element code, ANSYS for numerical simulation are employed to predict the optimized conditions. The results are verified by testing a number of closed end cylinders with various

G. H. Majzoobi; A. Ghomi

244

[Managing perilesional pressure ulcers].  

PubMed

The skin of elderly patients is very fragile and dry which impairs its function as a barrier and renders it more exposed to external attacks, perilesional complications around pressure ulcers are often linked to several interrelated mechanisms. These complications require, from the teams, in-depth knowledge of the care protocols. PMID:23785860

Perceau, Géraldine

245

The Pressure of Radiation  

Microsoft Academic Search

IN his letter of January 1 Prof. Callendar gives his reasons for doubting the formula for the pressure of radiation as it is usually accepted. He makes use of Boltzmann's proof of the fourth power law for the complete radiation, extends it to each separate frequency, and deduces that the energy in every frequency aught to be proportional to the

C. G. Darwin

1914-01-01

246

Pressurized Lunar Rover (PLR).  

National Technical Information Service (NTIS)

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 du...

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

1992-01-01

247

Pressurized downdraft gasifier  

Microsoft Academic Search

A pressurized downdraft gasifier is described for extracting high quality gas products from solid carbonaceous fuels having low rates of gasification comprising; gasifying chamber means with a lower burning zone therein, gas lock means connected to the gasifying chamber means for supplying fuel and downdraft combustion air to the gasifying chamber means, ash collection chamber means connected to the gasifying

1987-01-01

248

High Pressure Gas Tanks.  

National Technical Information Service (NTIS)

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 aga...

R. Quintana

2002-01-01

249

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

250

Favoritism Under Social Pressure  

Microsoft Academic Search

This paper is concerned with the effect of nonmonetary incentives on behavior, in particular with the study of social pressure as a determinant of corruption. We offer empirical evidence that shows how professional soccer referees favor home teams in order to satisfy the crowds in the stadium. Referees have discretion over the addition of extra time at the end of

Luis Garicano; Ignacio Palacios-Huerta; Canice Prendergast

2005-01-01

251

Favoritism Under Social Pressure  

Microsoft Academic Search

This paper provides empirical evidence of favoritism by agents, where that favoritism is generated by social pressure. To do so, we explore the behavior of professional soccer referees. Referees have discretion over the addition of extra time at the end of a soccer game (called injury time), to compensate for lost time due to unusual stoppages. We test for systematic

Luis Garicano; Ignacio Palacios-Huerta; Canice Prendergast

2001-01-01

252

Conservative Pressures on Curriculum.  

ERIC Educational Resources Information Center

|Pressure on the public schools is coming from conservative New Right religious-political groups. Their concerns focus on: (1) secular humanism--a Godless form of religion that the public schools are alleged to be teaching; (2) scientific evolution versus creationism--the balanced treatment statute; (3) Bible clubs and prayer in the classroom; and…

Bryson, Joseph E.

253

Pressure operated test valve  

SciTech Connect

A pressure operated test valve is described for use in a well test string in a well bore, the test string having a packer arranged for sealing the well bore to isolate the annulus between the well bore and the test string above the packer from that portion of the well bore below the packer. The valve consists of: a rotating ball valve movable between open and closed positions relative to the interior of the test string; a ball piston for shifting the rotating ball between the open and closed positions; biasing means for urging the ball piston to its valve closing position; a power fluid reservoir containing a power fluid; an axially shiftable power valve located within a power chamber, the power valve having opposed piston faces exposed by means of fluid passageways to fluid in the power fluid reservoir; and an axially slidable control valve located within a control chamber, the control valve having a pressure responsive annular area exposed to the power fluid for shifting the control valve and having internal passages for supplying pressurized power fluid to a selected face of the power valve to shift the power valve between a first position which isolates the ball piston and a second position which exposes the ball piston to annulus fluid pressure for shifting the ball to the open position.

Reardon, D.R.

1986-03-25

254

AIR-BLAST PHENOMENA IN THE HIGH-PRESSURE REGION  

Microsoft Academic Search

Surface level and aboveground static overpressures, near-surface ; differential pressures, and near-surface total pressures were measured on Burst ; Priscilla. Gages were placed at ground ranges from 450 ft to 4500 ft, with a ; concentration of measurements in the high-pressure region. Blast swttches, which ; measured arrival time only, were placed at several ranges, the closest at 100-ft ;

L. M. Swift; D. C. Sachs; A. R. Kriebel

1960-01-01

255

Metallic GGG at TPa pressure  

NASA Astrophysics Data System (ADS)

The Gadolinium Gallium Garnet (GGG) Gd3Ga5O12 has attracted a strong interest since Gas gun shock wave experiments unraveled a high pressure phase stiffer than diamond in the 100 GPa to 250 GPa range [Mashimo], recently confirmed by DAC static compression experiments up to 180 GPa [Mao]. The quasi uncompressible phase has been found to remain much more insulating than metallic fluid Hydrogen and appeared as a potential perfect anvil for off-Hugoniot Hydrogen shock compression to very high density. We have conducted laser driven shock experiments on GGG and determined the EoS through using velocimetry (VISAR) and pyrometry (SOP) diagnostics and an impedance match analysis with quartz standards at Omega-LLE and Jupiter-LLNL facilities. We have observed metallic reflectivity in GGG from ˜200 GPa to ˜2500 GPa. However, GGG is found to remain highly incompressible in this very high density and temperature range. References: [Mashimo] Mashimo et al., Transition to a Virtually Incompressible Oxide Phase at a Shock Pressure of 120 GPa (1.2 Mbar): Gd3Ga5O12, PRL 96, 105504 (2006) [Mao] Mao et al., Equation of state of a high-pressure phase of Gd3Ga5O12, PRB in press

Millot, Marius; Ali, Suzanne; Jeanloz, Raymond; Barrios, Maria; Boehly, Tom; Eggert, Jon; Collins, Gilbert

2011-06-01

256

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

SciTech Connect

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 deg. C. The theoretical model was validated through experiments carried out in the volumetric flow range from -7.0 to +7.0 l min{sup -1}. The nonlinear behavior allows sensitivities equal to 0.6 V l{sup -1} min for flow rates ranging from -2.0 to +2.0 l min{sup -1}, equal to 2.0 V l{sup -1} min for flow rates ranging from -3.0 to -2.0 l min{sup -1} and from +2.0 to +3.0 l min{sup -1}, up to 5.7 V l{sup -1} min at higher flow rates ranging from -7.0 to -3.0 l min{sup -1} and from +3.0 to +7.0 l min{sup -1}. The linear range extends from 3.0 to 7.0 l min{sup -1} with constant sensitivity equal to 5.7 V l{sup -1} min. The sensor is able to detect a flow-rate equal to 1.0 l min{sup -1} with a sensitivity of about 400 mV l{sup -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{sup -1}, corresponds to a negligible fluid dynamic resistance lower than 0.34 Pa l{sup -1} min.

Saccomandi, Paola; Schena, Emiliano; Silvestri, Sergio [Faculty of Biomedical Engineering, University Campus Bio-Medico, Via Alvaro del Portillo, 21, 00128 Rome (Italy)

2011-02-15

257

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

NASA Astrophysics Data System (ADS)

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.

Saccomandi, Paola; Schena, Emiliano; Silvestri, Sergio

2011-02-01

258

Unsteady pressure change in centrifugal pump impeller passages due to inlet swirl  

Microsoft Academic Search

The effects of an inlet swirl on the static pressure acting on impeller blades of a centrifugal pump were investigated experimentally. The instantaneous pressure on the blade surface was measured and the rapid change in the static pressure caused by the interaction of the vortex core and the impeller blades was clarified when a swirling flow was introduced. The pressure

K. Kikuyama; H. Hasegawa; T. Maeda

1992-01-01

259

Unsteady pressure change in centrifugal pump impeller passages due to inlet swirl  

Microsoft Academic Search

Effects of an inlet swirl on static pressure acting on impeller blades of a centrifugal pump were investigated experimentally. An instantaneous pressure on the blade surface was measured and the rapid change in the static pressure caused by the interaction of the vortex core and the impeller blades was clarified when a swirling flow was introduced. The pressure change was

Y. Hasegawa; K. Kikuyama; T. Maeda; M. Murakami

1990-01-01

260

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.

Evans, Leland B. (Antioch, CA); Malba, Vincent (Livermore, CA)

1997-01-01

261

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

262

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

263

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

264

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

265

High pressure storage vessel  

DOEpatents

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

266

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

267

Anesthesia and Intracranial Pressure  

Microsoft Academic Search

\\u000a Elevated intracranial pressure (ICP) may be the final stage of a number of different cerebral insults which share the ability\\u000a to augment intracranial volume. In neuroanesthesia practice this generally involves intracranial space occupying lesions such\\u000a as tumors, hematomas, venous obstruction, hydrocephalus, cerebral edema and\\/or combinations of the foregoing. Intracranial\\u000a hypertension exists when a sustained elevation in ICP to over 15

Harvey M. Shapiro

268

Hydraulic and Pressure Head Measurements with Strain Gauge Pressure Transducers.  

National Technical Information Service (NTIS)

The paper describes a tensiometer system of diaphragm type pressure transducers using strain gauge resistance elements to sense the minute deflection of the diaphragm under an applied pressure and reports some operational techniques.

A. Klute D. B. Peters

1966-01-01

269

High-pressure physics: Testing one's metal  

NASA Astrophysics Data System (ADS)

The search for the metallic state of hydrogen at ever higher static pressures has normally required experiments to be performed at temperatures near 100 K. Now, some 30 years after the first attempts at room-temperature compression, the observation of reflective dense hydrogen promises to bring it in from the cold.

Jephcoat, Andrew P.

2011-12-01

270

Pressure garment design tool to monitor exerted pressures.  

PubMed

Pressure garments are used in the treatment of hypertrophic scarring following serious burns. The use of pressure garments is believed to hasten the maturation process, reduce pruritus associated with immature hypertrophic scars and prevent the formation of contractures over flexor joints. Pressure garments are normally made to measure for individual patients from elastic fabrics and are worn continuously for up to 2 years or until scar maturation. There are 2 methods of constructing pressure garments. The most common method, called the Reduction Factor method, involves reducing the patient's circumferential measurements by a certain percentage. The second method uses the Laplace Law to calculate the dimensions of pressure garments based on the circumferential measurements of the patient and the tension profile of the fabric. The Laplace Law method is complicated to utilise manually and no design tool is currently available to aid this process. This paper presents the development and suggested use of 2 new pressure garment design tools that will aid pressure garment design using the Reduction Factor and Laplace Law methods. Both tools calculate the pressure garment dimensions and the mean pressure that will be exerted around the body at each measurement point. Monitoring the pressures exerted by pressure garments and noting the clinical outcome would enable clinicians to build an understanding of the implications of particular pressures on scar outcome, maturation times and patient compliance rates. Once the optimum pressure for particular treatments is known, the Laplace Law method described in this paper can be used to deliver those average pressures to all patients. This paper also presents the results of a small scale audit of measurements taken for the fabrication of pressure garments in two UK hospitals. This audit highlights the wide range of pressures that are exerted using the Reduction Factor method and that manual pattern 'smoothing' can dramatically change the actual Reduction Factors used. PMID:23790639

Macintyre, Lisa; Ferguson, Rhona

2013-06-20

271

Cuffless blood pressure monitoring using hydrostatic pressure changes.  

PubMed

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

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

2008-06-01

272

Tests of torispherical pressure vessel heads convex to pressure  

Microsoft Academic Search

Eighteen pressure vessel heads having nine different geometries and made from two different steels were subjected to monotonically increasing external pressure until collapse occurred. Deflection of the crown and strains in the most highly strained regions of the concave side of the heads were recorded as functions of pressure. All heads underwent permanent deformations. Four modes of failure were observed:

C. E. Washington; R. J. Clifton; B. W. Costerus

1977-01-01

273

RELATIONSHIP BETWEEN FRACTURE PROPAGATION PRESSURE AND PORE PRESSURE  

Microsoft Academic Search

Fracture stimulation data have been analyzed in conjunction with reservoir pressure buildup surveys to investigate the relationship between pore pressure and fracture propagation pressure in the geopressured Vicksburg Formation in S. Texas. The empirical relationship derived from the data can be used to improve well control and planning during drilling or workover and aid in stimulation design in partially depleted

L. B. Salz

1977-01-01

274

Surface pressure measurements by using pressure-sensitive paints  

Microsoft Academic Search

Until recently, wind tunnel measurements were made solely by pressure taps. But now an optical measurement method has been introduced and is replacing the usual instrumentation, at least for transonic wind tunnels: Pressure-Sensitive Paint, or PSP, which is a method generating an image of the pressure on the surface. The enthusiasm for this technique is prompted by the considerable savings

Y. Le Sant; M.-C. Mérienne

2005-01-01

275

Unsteady Force and Pressure Measurements.  

National Technical Information Service (NTIS)

Various aspects of the general problem of unsteady pressure and force measurement are described, and a number of examples of solutions to various force- and pressure-measurement problems are outlined. The examples are intended to illustrate the applicatio...

W. W. Willmarth

1971-01-01

276

Hazards in High Pressure Systems.  

National Technical Information Service (NTIS)

The High Pressure Systems Committee (HPSC) of the American Society of Mechanical Engineers is writing a set of rules and guides which will eventually be approved for treatment of safety concerns in high pressure operations. An introductory section of the ...

T. G. Priddy

1985-01-01

277

Blood pressure monitors for home  

MedlinePLUS

... home: a manual monitor, and an electronic or digital monitor. A digital monitor is a better option. It is very ... type of blood pressure monitor for home use. DIGITAL BLOOD PRESSURE DEVICES A digital device will also ...

278

Tank Pressure Control Experiment (TPCE).  

National Technical Information Service (NTIS)

The Tank Pressure Control Experiment (TPCE) is a small self-contained STS payload designed to test a jet mixer for cryogenic fluid pressure control. Viewgraphs are presented that describe project organization, experiment objectives and approach, risk mana...

M. Bentz

1992-01-01

279

Evaluation of Electric Pressure Fryers.  

National Technical Information Service (NTIS)

The report covers the evaluation of commercial electric pressure fryers to determine if the pressure frying method of cooking is superior to the deep fat frying method currently used in military food service facilities. The four phases evaluated were engi...

G. D. Bell K. A. Kornuta P. A. Bows R. E. Morgan R. L. Bernazzani

1973-01-01

280

Stability and breakdown of Ca{sup 13}CO{sub 3} melt associated with formation of {sup 13}C-diamond in static high pressure experiments up to 43 GPa and 3900 K  

SciTech Connect

Melting of calcium carbonate Ca{sup 13}CO{sub 3}, stability of the melt and its decomposition were studied in static high pressure experiments at pressures of 11-43 GPa and temperatures of 1600-3900 K using diamond anvil cell technique with laser heating. We observed formation of {sup 13}C-graphite (below 16 GPa) and {sup 13}C-diamond (between 16 and 43 GPa) on decomposition of the Ca{sup 13}CO{sub 3} melt at temperatures above 3400 K. At temperatures below 3400 K congruent melting of calcium carbonate was confirmed. The experimental results were applied to construction of the phase diagram of CaCO{sub 3} up to 43 GPa and 3900 K focusing at the melting curve of calcium carbonate and the decomposition phase boundary of CaCO{sub 3} melt. - Graphical abstract: Highlights: Black-Right-Pointing-Pointer Phase states of CaCO{sub 3} were studied at P=11-43 GPa and T=1600-3900 K. Black-Right-Pointing-Pointer {sup 13}C-diamond easily crystallizes in carbonate-carbon (Ca{sup 13}CO{sub 3-}{sup 13}C-graphite) melt-solutions. Black-Right-Pointing-Pointer Ca-carbonate melts congruently that was observed in experiments in DAC with laser heating. Black-Right-Pointing-Pointer Decomposition of CaCO{sub 3} melt, indicated by formation of graphite and/or diamond. Black-Right-Pointing-Pointer Decomposition of CaCO{sub 3} was observed at temperatures above 3400 K in the pressure interval studied.

Spivak, A.V., E-mail: spivak@iem.ac.ru [Institute of Experimental Mineralogy of the Russian Academy of Sciences, Chernogolovka, Moscow Region (Russian Federation); Litvin, Yu.A. [Institute of Experimental Mineralogy of the Russian Academy of Sciences, Chernogolovka, Moscow Region (Russian Federation); Ovsyannikov, S.V. [Bayerishes Geoinstitut, University of Bayreuth, Bayreuth (Germany); Dubrovinskaia, N.A. [Material Physics and Technology at Extreme Conditions, Laboratory of Crystallography, University of Bayreuth, Bayreuth (Germany); Dubrovinsky, L.S. [Bayerishes Geoinstitut, University of Bayreuth, Bayreuth (Germany)

2012-07-15

281

Mechanical Design of Pressure Parts  

Microsoft Academic Search

\\u000a A boiler is classified as a fired pressure vessel. Parts of the boiler that are subjected to high internal pressure of steam\\u000a or water are referred to here aspressure parts.Tubes, drum, and headers are examples of pressure parts. Other components likes burners, etc., are not subjected to such internal\\u000a pressure. As such they are classified as nonpressure parts. Selection of

Prabir Basu; Cen Kefa; Louis Jestin

282

Chromium at High Pressure  

NASA Astrophysics Data System (ADS)

Chromium has long served as the archetype of spin density wave magnetism. Recently, Jaramillo and collaborators have shown that Cr also serves as an archetype of magnetic quantum criticality. Using a combination of x-ray diffraction and electrical transport measurements at high pressures and cryogenic temperatures in a diamond anvil cell, they have demonstrated that the N'eel transition (TN) can be continuously suppressed to zero, with no sign of a concurrent structural transition. The order parameter undergoes a broad regime of exponential suppression, consistent with the weak coupling paradigm, before deviating from a BCS-like ground state within a narrow but accessible quantum critical regime. The quantum criticality is characterized by mean field scaling of TN and non mean field scaling of the transport coefficients, which points to a fluctuation-induced reconstruction of the critical Fermi surface. A comparison between pressure and chemical doping as means to suppress TN sheds light on different routes to the quantum critical point and the relevance of Fermi surface nesting and disorder at this quantum phase transition. The work by Jaramillo et al. is broadly relevant to the study of magnetic quantum criticality in a physically pure and theoretically tractable system that balances elements of weak and strong coupling. [4pt] [1] R. Jaramillo, Y. Feng, J. Wang & T. F. Rosenbaum. Signatures of quantum criticality in pure Cr at high pressure. Proc. Natl. Acad. Sci. USA 107, 13631 (2010). [0pt] [2] R. Jaramillo, Y. Feng, J. C. Lang, Z. Islam, G. Srajer, P. B. Littlewood, D. B. McWhan & T. F. Rosenbaum. Breakdown of the Bardeen-Cooper-Schrieffer ground state at a quantum phase transition. Nature 459, 405 (2009).

Jaramillo, Rafael

2012-02-01

283

Pressure modulation of water vapour  

Microsoft Academic Search

Pressure modulation radiometry has been used in several balloon and satellite experiments over the last two decades for remote sounding of atmospheric composition and temperature. Motivated in part by difficulties in the interpretation of water vapour measurements by the Stratospheric and Mesospheric Sounder on Nimbus 7, the pressure cycle within a pressure modulator has been measured under various conditions for

G. R. Davis

1993-01-01

284

Capacitive Silicon Differential Pressure Sensor  

Microsoft Academic Search

SUMMARY A capacitive differential pressure sensor based on silicon bulk micromachining is presented. This sensor, which is part of a flow metering system, transforms the differential pressure delivered by a fluidic oscillator into capacitance variations. These variations are then converted by an ASIC into a digital output signal. The system specifications require the detection of differential pressures as low as

J. Hermann; C. Bourgeois; F. Porret; B. Kloeck

1995-01-01

285

Myths about High Blood Pressure  

MedlinePLUS

... High blood pressure is also the No. 1 cause of stroke. 5) Myth. People with high blood pressure have ... can increase blood pressure dramatically. It can also cause heart failure, lead to stroke and produce irregular heartbeats. Too much alcohol can ...

286

Pressure Inactivation of Bacillus Endospores  

Microsoft Academic Search

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

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

2004-01-01

287

Systolic blood pressure and mortality  

Microsoft Academic Search

Summary Background The current systolic blood-pressure threshold for hypertension treatment is 140 mm Hg for all adults. WHO and the International Society of Hypertension have proposed that normal pressure be lower than 130 mm Hg, with an optimum pressure of less than 120 mm Hg. These recommendations are based largely on the assumption that cardiovascular and overall mortality depend in

Sidney Port; Linda Demer; Robert Jennrich; Donald Walter; Alan Garfinkel

2000-01-01

288

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

289

Fiber-optic pressure sensor  

DOEpatents

A pressure wave sensor utilizing fiber optic interferometry techniques to determine pressure in a bar. Light from a fiber optic coil around the bar is mixed with light from a reference optical fiber to produce interference fringes as a function of time. These fringes over time are related to the pressure versus time existing in the bar. 2 figs.

Dingus, R.S.

1989-03-10

290

Collapse pressures of biodegradable stents  

Microsoft Academic Search

Biodegradable stent prototypes were produced from poly l-lactic acid polymers with different molecular weights. The effects of molecular weight, drug incorporation and stent design on the collapse pressure of the stents were evaluated. While molecular weights did not show a significant effect on the collapse pressure of the stents, drug incorporation at high percentage decreased the collapse pressure of the

Subbu Venkatraman; Tan Lay Poh; Tjong Vinalia; Koon Hou Mak; Freddy Boey

2003-01-01

291

Amorphous Materials at High Pressure  

Microsoft Academic Search

\\u000a This chapter reviews the different pathways towards high-pressure amorphization, how high-pressure amorphs may be characterized\\u000a and what are the potential mechanisms causing pressure-induced amorphization and amorphous-amorphous transitions.

Chrystele Sanloup

2010-01-01

292

HIGH PRESSURE DIES  

DOEpatents

A press was invented for subjecting specimens of bismuth, urania, yttria, or thoria to high pressures and temperatures. The press comprises die parts enclosing a space in which is placed an electric heater thermally insulated from the die parts so as not to damage them by heat. The die parts comprise two opposed inner frustoconical parts and an outer part having a double frustoconical recess receiving the inner parts. The die space decreases in size as the inner die parts move toward one another against the outer part and the inner parts, though very hard, do not fracture because of the mode of support provided by the outer part.

Wilson, W.B.

1960-05-31

293

Pressure, velocity, and temperature sensitivities of a bleed-type pressure sensor  

NASA Astrophysics Data System (ADS)

This paper presents the results of a complete series of tests and calibrations of a bleed-type pressure sensor used in order to determine in-stream static pressure fluctuations in a turbulent boundary layer just above a pure laboratory wind-wave field. The static calibrations show that for air flow mean velocities lower than 15 m/s, the sensor response depends not only upon the pressure but also upon the velocity and the temperature of the air flow. Dynamic calibrations prove that the temperature and velocity sensitivities depend strongly upon the frequency. They are important for low frequencies and equal to zero only for frequencies greater than 0.1 Hz if the sensor is operated in an isothermal turbulent flow and greater than 1 Hz for a nonisothermal flow. Pressure sensitivity does not depend upon frequency for a range from dc to 600 Hz.

Giovanangeli, J. P.; Chambaud, P.

1987-07-01

294

Pressure-confined Lyman-alpha clouds  

SciTech Connect

Results are presented of numerical models of pressure-confined spherical gas clouds which produce absorption resembling the low to intermediate atomic column density lines found in high-redshift QSO spectra. One-dimensional hydrodynamical models including electron conduction are described, and the rate equations are solved to find ionization and excitation states. Results are presented for both static and adiabatically expanding confining media covering a range of initial pressures. It is found that Ly-alpha lines are very similar over a wide range of conditions and that the most promising diagnostic of pressure is to compare the column density in H I to that in He I and He II. No single-pressure model can explain the wide range of observed H I column densities. 18 references.

Baron, E.; Carswell, R.F.; Hogan, C.J.; Weymann, R.J.

1989-02-01

295

Toe pressure measurements compared to ankle artery pressure measurements.  

PubMed

The Trans-Atlantic Inter-Society Consensus (TASC)-recommended absolute toe pressure is < 30-50 mm Hg for definition of chronic critical limb ischemia (CLI). Toe pressures can be measured by different techniques. The authors analyzed the clinical use of the Doppler technique and an automatic device with optical sensors and estimated their value in documentation of chronic critical limb ischemia compared to ankle artery pressures. Three different investigations were performed: (1) In 16 healthy subjects the digital artery pressures were measured by using 3 different optical sensors (transmission, reflection, and microcirculation sensor) and compared to the systolic brachial pressure. (2) In 50 patients with and without peripheral arterial occlusive disease the toe pressures at digits 1 and 2 of both feet were determined by Doppler technique (8 MHz) and by optical sensors (cuff width constant 1.5 cm) and were compared to the ankle artery pressure determined by Doppler technique. (3) In 175 patients the toe pressures were measured at 1 toe and the ankle artery pressures were determined. In this group they estimated the clinical use of the toe pressure in regard to the definition of CLI (toe pressure < 50 mm Hg) compared to the ankle pressure < 70 mm Hg. The digital artery pressures measured with the different optical sensors, and the systolic brachial pressures were not significantly different and the correlation coefficients were around 0.7. In 21 of 50 patients the toe pressure at D1 and D2 could not be measured by Doppler technique because with the applied cuff no Doppler signal could be detected at the tip of the toe, but in 24 of these 29 patients the optical measurement was possible. Mean toe pressures at D1 were 108 +/- 45 mm Hg and D2 102 +/- 45 mm Hg, which were statistically not different. The correlation coefficient for the highest ankle artery pressure and the highest toe pressure determined by the Doppler technique was 0.389; for the highest ankle artery pressure and the toe pressure measured by the optical sensors it was 0.369, and for the toe pressures measured by Doppler technique and the optical sensors it was 0.506. Defining systolic ankle artery pressure < or = 50 to 70 mm Hg as the golden standard for CLI, the sensitivity of optical toe pressure measurement for the detection of CLI was 8%, the specificity was 96%, the positive predictive value 12%, and the negative predictive value was 94%. Independent of technique the absolute systolic toe pressures did not correlate with the absolute systolic ankle pressures. The optical measurement was more suitable for toe pressure measurement because it could be used in 90% of all patients. All in all, toe pressure measurements are more useful to exclude CLI than to prove it. PMID:12593494

Kröger, Knut; Stewen, Christian; Santosa, Frans; Rudofsky, Gottfried

2003-01-01

296

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

297

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

298

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

299

Clinical management of pressure ulcers.  

PubMed

Pressure ulcers are chronic and difficult to heal. Pressure-reducing devices are clearly superior to a standard hospital mattress in preventing pressure ulcers, but only limited evidence and clinical intuition supports pressure-reducing devices in improving the healing rate of pressure ulcers. Local wound treatment should aim at maintaining a moist wound environment. The choice of a particular dressing depends on wound characteristics, such as the amount of exudate, dead space, or wound location. Nutritional status should be addressed as a process of good care. Debridement may improve time to a clean wound bed, but no clearly superior approach has been demonstrated. PMID:23571035

Thomas, David R

2013-05-01

300

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

301

Microbial activity at gigapascal pressures.  

PubMed

We observed physiological and metabolic activity of Shewanella oneidensis strain MR1 and Escherichia coli strain MG1655 at pressures of 68 to 1680 megapascals (MPa) in diamond anvil cells. We measured biological formate oxidation at high pressures (68 to 1060 MPa). At pressures of 1200 to 1600 MPa, living bacteria resided in fluid inclusions in ice-VI crystals and continued to be viable upon subsequent release to ambient pressures (0.1 MPa). Evidence of microbial viability and activity at these extreme pressures expands by an order of magnitude the range of conditions representing the habitable zone in the solar system. PMID:11859192

Sharma, Anurag; Scott, James H; Cody, George D; Fogel, Marilyn L; Hazen, Robert M; Hemley, Russell J; Huntress, Wesley T

2002-02-22

302

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.

303

Pressurized downdraft gasifier  

SciTech Connect

A pressurized downdraft gasifier is described for extracting high quality gas products from solid carbonaceous fuels having low rates of gasification comprising; gasifying chamber means with a lower burning zone therein, gas lock means connected to the gasifying chamber means for supplying fuel and downdraft combustion air to the gasifying chamber means, ash collection chamber means connected to the gasifying chamber means to receive ash emanating from the burning zone through a throated zone in the bottom of the gasifying chamber means, a cylindrical grate bar assembly concentrically depending from the gasifying chamber means below the throated zone and extending downwardly into the ash collection chamber means, the cylindrical grate bar assembly including circular grate bars vertically-spaced from one another.

Weaver, L.E.

1987-04-21

304

Cradle and pressure grippers  

DOEpatents

A gripper that is designed to incorporate the functions of gripping, supporting and pressure tongs into one device. The gripper has two opposing finger sections with interlocking fingers that incline and taper to form a wedge. The interlocking fingers are vertically off-set so that the opposing finger sections may close together allowing the inclined, tapered tips of the fingers to extend beyond the plane defined by the opposing finger section's engagement surface. The range of motion defined by the interlocking relationship of the finger sections allows the gripper to grab, lift and support objects of varying size and shape. The gripper has one stationary and one moveable finger section. Power is provided to the moveable finger section by an actuating device enabling the gripper to close around an object to be lifted. A lifting bail is attached to the gripper and is supported by a crane that provides vertical lift.

Muniak, John E. (New York, NY)

2001-01-01

305

Cradle and pressure grippers  

SciTech Connect

A gripper that is designed to incorporate the functions of gripping, supporting and pressure tongs into one device. The gripper has two opposing finger sections with interlocking fingers that incline and taper to form a wedge. The interlocking fingers are vertically off-set so that the opposing finger sections may close together allowing the inclined, tapered tips of the fingers to extend beyond the plane defined by the opposing finger section's engagement surface. The range of motion defined by the interlocking relationship of the finger sections allows the gripper to grab, lift and support objects of varying size and shape. The gripper has one stationary and one moveable finger section. Power is provided to the moveable finger section by an actuating device enabling the gripper to close around an object to be lifted. A lifting bail is attached to the gripper and is supported by a crane that provides vertical lift.

Muniak, John E. (New York, NY)

2001-01-01

306

Pressurized continuous chromatography  

SciTech Connect

A pressurized continuous annular chromatograph has been developed for preparative separations. This device utilizes a slowly rotating annular bed of sorbent material, fixed multiple feed points, and fixed withdrawal locations. Most of our investigations have been performed with a 28-cm-diam column, but a larger model is being designed and constructed. The separation of copper, nickel, and cobalt components from a carbonate solution has been studied in detail. This solution simulates the leach liquor from the Caron process for recovering nickel and cobalt from laterite ores. Use of continuous gradient elution has been demonstrated. Recent studies have investigated several separations, including that of zirconium and hafnium (necessary for the production of zirconium for use in nuclear reactors), on a preparative scale. This system, because of its continuous feed and product withdrawal, its adaptability to large-scale operations, and its ability to separate many components, is expected to make chromatography a more competitive process in the industrial sector.

Canon, R.M.; Begovich, J.M.; Sisson, W.G.

1980-04-01

307

Low pressure hydrogen discharges  

SciTech Connect

This article presents a fluid-plasma model of the free-fall regime of maintenance of high-frequency discharges in hydrogen. The obtained results are for the radial profiles of the concentrations and the velocities of electrons, positive H{sup +}, H{sub 2}{sup +}, and H{sub 3}{sup +} ions, negative H{sup -} ions, potential of the radial dc electric field, and electron temperature. The importance of the directed motion of the charged particles in the radial dc electric field, the negative ion behavior in the discharge, and the description of the discharge characteristics by continuous radial profiles, which smoothly cover the total cross section of discharge, are stresses. A strong impact of the negative ions on the formation of the self-consistent discharge structure is shown. The discussions are in terms of changing gas pressure and electron concentration at the discharge axis.

Paunska, Ts.; Schlueter, H.; Shivarova, A.; Tarnev, Kh. [Faculty of Physics, Sofia University, BG-1164 Sofia (Bulgaria); Institut fuer Experimentalphysik II, Ruhr-Universitaet Bochum, D-44780 Bochum (Germany); Faculty of Physics, Sofia University, BG-1164 Sofia (Bulgaria); Department of Applied Physics, Technical University-Sofia, BG-1000 (Bulgaria)

2006-02-15

308

Temperature and pressure activated pressure relieving spark plug  

US Patent & Trademark Office Database

A spark plug for venting excessive engine cylinder pressure may be either pressure or temperature activated. A vent passage is created in a conventional spark plug by drilling an air vent through the housing of a conventional spark plug to a point that experiences cylinder pressures. The air vent is then sealed with a mechanical element of known structural strength and temperature response. Upon the development of excessive engine temperature, cylinder pressure, or both, the sealing element gives way, generating an air passage from the combustion chamber to the atmosphere through which cylinder pressure is vented. By venting excessive pressure, the disastrous effects of detonation, hydrolock, and other deleterious engine conditions may be avoided. Prior to the failure of the seal, the spark plug functions identically to a conventional spark plug.

2002-05-07

309

High-pressure fluorescence applications.  

PubMed

Fluorescence is the most widely used technique to study the effect of pressure on biochemical systems. The use of pressure as a physical variable sheds light into volumetric characteristics of reactions. Here we focus on the effect of pressure on protein solutions using a simple unfolding example in order to illustrate the applications of the methodology. Topics covered in this review include the relationships between practical aspects and technical limitations; the effect of pressure and the study of protein cavities; the interpretation of thermodynamic and relaxation kinetics; and the study of relaxation amplitudes. Finally, we discuss the insights available from the combination of fluorescence and other methods adapted to high pressure, such as SAXS or NMR. Because of the simplicity and accessibility of high-pressure fluorescence, the technique is a starting point that complements appropriately multi-methodological approaches related to understanding protein function, disfunction, and folding from the volumetric point of view. PMID:24108623

Dellarole, Mariano; Royer, Catherine A

2014-01-01

310

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

311

Pressure as an environmental parameter for microbial life - A review.  

PubMed

Microbial life has been prevailing in the biosphere for the last 3.8Ga at least. Throughout most of the Earth's history it has experienced a range of pressures; both dynamic pressure when the young Earth was heavily bombarded, and static pressure in subsurface environments that could have served as a refuge and where microbial life nowadays flourishes. In this review, we discuss the extent of high-pressure habitats in early and modern times and provide a short overview of microbial survival under dynamic pressures. We summarize the current knowledge about the impact of microbial activity on biogeochemical cycles under pressures characteristic of the deep subsurface. We evaluate the possibility that pressure can be a limiting parameter for life at depth. Finally, we discuss the open questions and knowledge gaps that exist in the field of high-pressure geomicrobiology. PMID:23891571

Picard, Aude; Daniel, Isabelle

2013-07-01

312

Experimental study of three exit pressure distortions on turbine performance  

NASA Astrophysics Data System (ADS)

A cold flow air test of the Space Shuttle Main Engine (SSME) High Pressure Fuel Turbopump (HPFTP) turbine was conducted with a circumferential pressure distortion at the turbine exit. The effects of three circumferential exit pressure distortions on turbine efficiency and pressure ratio, are presented. Circumferential and radial total pressure, total temperature, static pressure, and flow angle distributions at the turbine exit are also presented. Efficiency and total-to-total pressure ratio are shown to have a circumferential variation as high as 13.7 percent (or points of efficiency) and 7.1 percent, respectively. A slight pressure distortion was measured downstream of the first stage nozzle and the distortion increased across subsequent blade rows to a maximum downstream of the second stage rotor for all three plates. A brief discussion of the test facility, model, instrumentation, and test plan is given for completeness.

Gaddis, Stephen W.; Boynton, James L.

1993-06-01

313

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

314

High pressure EWOD digital microfluidics  

Microsoft Academic Search

We are developing new electrowetting-on-dielectric (EWOD) digital microfluidic systems for operating at non-atmospheric conditions. The first generation is a compact pressure chamber with an electric feed-through, enabling EWOD operation within a gaseous medium of well-controlled pressure and composition. EWOD performance is insensitive to chamber pressure because the chip is of open-channel architecture. We demonstrate two different types of previously unachievable

W. C. Nelson; M. Yen; P. Y. Keng; R. M. van Dam; C.-J. Kim

2011-01-01

315

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

316

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

317

Convertible socket for pressure gauge  

SciTech Connect

This patent describes a pressure gauge having a case in which is disposed a Bourdon tube and a base socket connected to the Bourdon tube for placing the tube in pressure communication with a fluid pressure source. Base socket has a rearward face and a bottom face with respect to the gauge adjacent openings defined through the case and an internal passage communication with the tube. It includes means for connecting a source of fluid pressure to the socket selectively through one of the case openings to the bottom face or the rearward face.

Bissell, R.D.

1990-01-01

318

High pressure heterogeneous catalysis in a low pressure UHV environment  

SciTech Connect

The major thrust of our research is to carry out for the first time a heterogeneous catalytic reaction that normally is observed only at high pressures (>1 atm) of reactant gas at low pressures (<10{sup {minus}4} Torr) in an ultrahigh vacuum environment. The reaction we have chosen is the steam reforming of methane on a Ni(111) crystal.

Ceyer, S.T.

1990-01-01

319

Pressure Breathing During G Without a Counter-Pressure Vest.  

National Technical Information Service (NTIS)

This report was delivered to Air Combat Command (ACC/DRS) in response to their request for a study of use of the COMBAT EDGE positive pressure breathing (PPB) system without its chest counter-pressure vest. The vest is worn to balance intra-thoracic press...

R. O'Connor W. Isdahl P. Werchan U. Balldin

2004-01-01

320

Vapor Pressure of Fluids in High-Pressure Gas Atmospheres.  

National Technical Information Service (NTIS)

As part of the investigation of the critical parameters in the combustion of hydraulic fluids, experiments were conducted to verify the accuracy of the Poynting equation which predicts the effect of inert gas pressure upon the vapor pressure of a liquid. ...

D. R. Ventriglio R. W. McQuaid

1967-01-01

321

Diamond Anvil Cells: A New Tool for High Pressure Studies.  

National Technical Information Service (NTIS)

Literally hundreds of papers have appeared in the last few years covering a myriad of uses of the diamond anvil cells. The crescendo shows no signs of abating. Static pressures as high as 1.8 megabar have been reported. Still higher pressures appear possi...

R. D. Taylor

1985-01-01

322

Swedish healthcare under pressure.  

PubMed

Swedish health care, run by local governments at both the regional (county) and the municipal levels, has been under pressure during the last 15 years, following increased scrutiny of performance and demand for cost-containment. Health-care expenditures per capita and levels of resource inputs have grown, but more slowly than in other EU countries. At the same time, the number of elderly people has increased, as have options for medical treatment. In the late 1980s, several local governments referred to long waiting-lists for elective treatment and anecdotal evidence of inefficiency and poor responsiveness when arguing for market-oriented reforms. A purchaser-provider split followed, and so did changes in the payment systems for health-care providers. According to the available evidence, these reforms yielded an increased volume of services in the short run; but traditional hierarchical management soon replaced the new incentives. Moreover, evidence suggests that changes introduced by the national government, and the deteriorating funding conditions together with a continued use of new medical technology, have had more far-reaching effects on health-care output and outcome than local-government reforms. PMID:16161198

Anell, Anders

2005-09-01

323

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

2012-01-20

324

Fuel pressure regulator  

SciTech Connect

This patent describes a fuel pressure regulator for internal combustion of automobiles and the like. It comprises a body including first, second and third chambers; a resilient impervious diaphragm separating the second and third chambers; a fuel inlet communicating with the first chamber; a fuel outlet communicating with the second chamber; a passageway for permitting fluid communication between the first and second chambers; a ball valve means adjacent one end of the passageway ball valve means comprising a movable ball and a movable valve seat; first biasing means for biasing the ball valve means at one end of the passageway; actuating means for actuating the ball valve means at the one end of the passageway, the actuating comprising a piston positioned in the second chamber in abutment with one side of the resilient impervious diaphragm and a stem extending from the piston with its distal end adapted to bear against the ball of the valve means; second biasing means in the third chamber in abutment with the other side of the resilient impervious diaphragm for biasing the resilient diaphragm to move the piston toward the first chamber; stem guide means positioned between the first and second chambers along the length of the stem and intermediate the ends of the stem for guiding the stem to limit the motion of the stem to a substantially linear, reciprocating motion while in contact with the ball of the ball valve means.

Grant, B.

1992-05-19

325

Advanced Pressure Boundary Materials  

SciTech Connect

Increasing the operating temperatures of fossil power plants is fundamental to improving thermal efficiencies and reducing undesirable emissions such as CO{sub 2}. One group of alloys with the potential to satisfy the conditions required of higher operating temperatures is the advanced ferritic steels such as ASTM Grade 91, 9Cr-2W, and 12Cr-2W. These are Cr-Mo steels containing 9-12 wt% Cr that have martensitic microstructures. Research aimed at increasing the operating temperature limits of the 9-12 wt% Cr steels and optimizing them for specific power plant applications has been actively pursued since the 1970's. As with all of the high strength martensitic steels, specifying upper temperature limits for tempering the alloys and heat treating weldments is a critical issue. To support this aspect of development, thermodynamic analysis was used to estimate how this critical temperature, the A{sub 1} in steel terminology, varies with alloy composition. The results from the thermodynamic analysis were presented to the Strength of Weldments subgroup of the ASME Boiler & Pressure Vessel Code and are being considered in establishing maximum postweld heat treatment temperatures. Experiments are also being planned to verify predictions. This is part of a CRADA project being done with Alstom Power, Inc.

Santella, Michael L [ORNL; Shingledecker, John P [ORNL

2007-01-01

326

Pressure gradient measurements in volcanic diffuse gas emanations  

Microsoft Academic Search

We describe a differential pressure measurement device which allows one to estimate fluid pressure gradients ranging from 6.3×10-6 to 3.15×10-3atm\\/m in soil diffuse volcanic gas emanations. The lower limit roughly corresponds to the atmospheric (static) pressure gradient due to gravity, and should represent the minimum required value for volcanic gases to reach the Earth's surface by viscous flow. In the

Giuseppe Natale; Pedro Hernández; Toshiya Mori; Kenji Notsu

2000-01-01

327

Pressure Dependence of Laser-Induced Dielectric Breakdown in Water  

Microsoft Academic Search

The effects of pressure on laser-induced breakdown events at superthreshold irradiances in water were investigated over a range of pressures from 0 to 1380 bar. Breakdown events were generated using 5-ns Nd:YAG laser pulses of wavelength 532-nm. Observations of breakdown events were made using imaging and single detector techniques. Applications for use as a static and\\/or acoustic pressure sensor were

Jonathan Robert Sukovich; Ashwinkumar Sampathkumar; R. Glynn Holt

2011-01-01

328

Head pressure control system for refrigeration unit  

SciTech Connect

A refrigeration system having a closed refrigerant loop is described comprising: an evaporator; an air cooled condenser; a compressor connected between the evaporator and the condenser; an expansion device connected between the condenser and the evaporator; a receiver for separating gaseous refrigerant and liquid refrigerant prior to the liquid refrigerant entering the expansion device; a pressure regulating means connecting the compressor to the receiver for automatically maintaining the pressure in the receiver and the condenser in cool ambient conditions; a means connecting the outlet of the condenser to the receiver, including a check valve permitting flow from the condenser into the top of the receiver; a bypass means for diverting sub-cooled liquid refrigerant from the condenser to the expansion device, and a liquid outlet from the receiver extending downwardly from the receiver and interconnected to the bypass means at an elevation below the receiver whereby a static pressure heads of liquid refrigerant is present in the bypass means.

O'Neal, A.

1988-04-05

329

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

330

Static Pressure Fractionation Characteristics of Water Hyacinth.  

National Technical Information Service (NTIS)

Up to 82% of the water in water hyacinth was removed from prepared plants by multiple pressings in a screen-lined cylinder with a low speed press. Plants as wet as 2089% dry basis moisture content were pressed to as low as 404% dry basis moisture content ...

L. O. Bagnall F. J. Corral

1974-01-01

331

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

332

Liberating effects of group pressure  

Microsoft Academic Search

A study of constructive conformity. Experimental studies have generally pointed to the negative effects of group pressure. This experiment shows that in specifiable circumstances group pressure enables a person to resolve conflicting forces in a direction congruent with his values. In Exp. I Ss are instructed to administer increasingly more severe shocks to a victim. In Exp. II, 2 confederates

Stanley Milgram

1965-01-01

333

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

334

Pressure sores and hip fractures.  

PubMed

Development of pressure sores during hospital admission causes morbidity and distress to the patient, increases strain on nursing resources, delaying discharge and possibly increasing mortality. A hip fracture in elderly patients is a known high-risk factor for development of pressure sores. We aimed to determine the current incidence of pressure sores and identify those factors which were associated with an increased risk of pressure sores. We retrospectively analysed prospectively collected data of 4654 consecutive patients admitted to a single unit. One hundred and seventy-eight (3.8%) of our patients developed pressure sores. Patient factors that increased the risk of pressure sores were increased age, diabetes mellitus, a lower mental test score, a lower mobility score, a higher ASA score, lower admission haemoglobin and an intra-operative drop in blood pressure. The risk was higher in patients with an extracapsular neck of femur fracture and patients with an increased time interval between admission to hospital and surgery. Our studies indicate that while co-morbidities constitute a substantial risk in an elderly population, the increase in incidence of pressure sores can be reduced by minimising delays to surgery. PMID:18234201

Haleem, S; Heinert, G; Parker, M J

2008-01-29

335

Pressure Ulcer Prevention and Repositioning  

Microsoft Academic Search

Repositioning is an effective way to prevent pressure ulcers, but it must be combined with sitting and lying positions in\\u000a which the pressure is as low as possible. There are many opinions but little actual research on the frequency of position\\u000a changes.

Tom Defloor; Katrien Vanderwee; Doris Wilborn; Theo Dassen

336

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

337

Sparking Potentials at Low Pressures  

Microsoft Academic Search

At gas pressures less than the Paschen critical value the sparking potential rises rapidly with decrease in pressure. Measurements are difficult because of undesired discharges over longer paths than the intended one. A sparking tube has been constructed with which measurements have been made on air, carbon dioxide, hydrogen, and helium up to 24 kv with nickel electrodes, and on

Robert B. Quinn

1939-01-01

338

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

339

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

340

High pressure study on gibbsite  

NASA Astrophysics Data System (ADS)

The water reservoir in the Earth’s mantle is one of the key subjects in geoscience, and recently Murakami M et al. (Science, 295, 1885, 2002) revealed that Earth's lower mantle may store more water than the oceans. The studies on hydrous minerals under high pressure and temperature are important for understanding the dynamics processes of water in the mantle environments. For gibbsite case, previous studies by Huang et al. (Phys. Chem. Minerals, 26, 576, 1999, &Geophys. Res. Lett, 23, 3083, 1996) reported high pressure induced phase transition above 3 GPa, and the high-pressure polymorph was identified as nordstrandite which is a triclinic phase. In this work, in situ high pressure X-ray diffraction experiments are performed by using various pressure transiting medium including of helium, argon, methanol-ethanol mixture, and mineral oil. The non-hydrostatic and quasi-hydrostatic high pressure results are compared, and the high-pressure phase above 3GPa can be indexed as a higher symmetry phase, i. e. from monoclinic (gibbsite) to orthorhombic structure which is in contrast to the previous reports. The compressibility of gibbsite and its high-pressure polymorph up to 50GPa at room temperature are obtained.

Liu, H.; Hu, J.; Xu, J.; Shu, J.; Mao, H.; Chen, J.

2003-04-01

341

Development of Soil Pressure Gages.  

National Technical Information Service (NTIS)

This report describes a soil pressure measuring system which involves quick-freezing a zone of soil in the 'free-field,' excavating a cavity in the frozen zone, suspending a triaxially sensitive pressure gage in the cavity, and surrounding the gage with a...

E. C. W. A. Geuze R. Y. K. Cheng

1965-01-01

342

Pressure difference receiving ears.  

PubMed

Directional sound receivers are useful for locating sound sources, and they can also partly compensate for the signal degradations caused by noise and reverberations. Ears may become inherently directional if sound can reach both surfaces of the eardrum. Attempts to understand the physics of such pressure difference receiving ears have been hampered by lack of suitable experimental methods. In this review, we review the methods for collecting reliable data on the binaural directional cues at the eardrums, on how the eardrum vibrations depend on the direction of sound incidence, and on how sound waves behave in the air spaces leading to the interior surfaces of eardrums. A linear mathematical model with well-defined inputs is used for exploring how the directionality varies with the binaural directional cues and the amplitude and phase gain of the sound pathway to the inner surface of the eardrum. The mere existence of sound transmission to the inner surface does not ensure a useful directional hearing, since a proper amplitude and phase relationship must exist between the sounds acting on the two surfaces of the eardrum. The gain of the sound pathway must match the amplitude and phase of the sounds at the outer surfaces of the eardrums, which are determined by diffraction and by the arrival time of the sound, that is by the size and shape of the animal and by the frequency of sound. Many users of hearing aids do not obtain a satisfactory improvement of their ability to localize sound sources. We suggest that some of the mechanisms of directional hearing evolved in Nature may serve as inspiration for technical improvements. PMID:18364558

Michelsen, Axel; Larsen, Ole Naesbye

2007-12-19

343

[Monitoring of intracranial pressure].  

PubMed

The use of intraparenchymatous ICP sensor is becoming increasingly popular at the expense of the traditional intraventricular catheter method, in spite of the impossibility, with the former technic, to correct a possible zero drift. The decision to initiate or discontinue ICP monitoring is essentially based upon whether suggestive aspects of raised ICP are or not present on CT-scan. The degree of basal cisterns effacement is particularly informative. The same data from successive CT-scans are used to check the validity of the monitoring. Predefining critical levels of ICP and cerebral perfusion pressure (CPP) allows to establish practical guide-lines for treatment. Cerebral ischemia is considered very likely when ICP rises above 30 mmHg. Regarding CPP, the therapeutical goal is to avoid its reduction under the critical level of 60-80 mmHg. As these thresholds vary with the patients age and the type of lesion, a parallel evaluation of cerebral ischemia by other methods is mandatory. Transcranial doppler allows an easy detection of critical reduction of arterial flow. However, in case of flow hypervelocity, interpretation needs measurement of absolute cerebral blood flow values. Cerebral venous oxygen saturation monitoring, at the level of the jugular golf, shows desaturation episodes indicative of cerebral ischemia. Blood sampling for determination of arterial and jugular venous lactate concentrations allows calculation of the lactate oxygen index, a practical correlate of the degree of cerebral ischemia. ICP measurement alone is of limited value to understand the cerebral hemodynamical and metabolical situation in severe brain injury. Preceding the rise of ICP, there exists a compensation phase during which a progressive decrease of intracranial compliance is the important event. Even more earlier, posttraumatic cellular metabolic dysfunctions are to-day objectives for a neurochemical monitoring. Therefore a special technical and human environment has became mandatory to take a real benefit from ICP monitoring. PMID:8762256

Artru, F

1996-01-01

344

Pressure rig for repetitive casting  

NASA Astrophysics Data System (ADS)

The invention is a pressure rig for repetitive casting of metal. 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 into the mold. A ceramic cavity which holds molten metal is lined with blanket-type insulating material, necessitating only a relining for subsequent use and eliminating the lengthy cavity preparation inherent in previous rigs. In addition, the expandable rubber diaphragm is protected by the insulating material thereby decreasing its vulnerability to heat damage. As a result of the improved design the life expectancy of the pressure rig contemplated by the present invention is more than doubled. Moreover, the improved heat protection has allowed the casting of brass and other alloys with higher melting temperatures than possible in the conventional pressure rigs.

Vasquez, Peter; Hutto, William R.; Philips, Albert R.

1989-09-01

345

Fundamentals of high pressure adsorption.  

PubMed

High-pressure adsorption attracts research interests following the world's attention to alternative fuels, and it exerts essential effect on the study of hydrogen/methane storage and the development of novel materials addressing to the storage. However, theoretical puzzles in high-pressure adsorption hindered the progress of application studies. Therefore, the present paper addresses the major theoretical problems that challenged researchers: i.e., how to model the isotherms with maximum observed in high-pressure adsorption; what is the adsorption mechanism at high pressures; how do we determine the quantity of absolute adsorption based on experimental data. Ideology and methods to tackle these problems are elucidated, which lead to new insights into the nature of high-pressure adsorption and progress in application studies, for example, in modeling multicomponent adsorption, hydrogen storage, natural gas storage, and coalbed methane enrichment, was achieved. PMID:19928941

Zhou, Yaping; Zhou, Li

2009-12-01

346

Organic electronics based pressure sensor towards intracranial pressure monitoring  

NASA Astrophysics Data System (ADS)

The intra-cranial space, which houses the brain, contains cerebrospinal fluid (CSF) that acts as a fluid suspension medium for the brain. The CSF is always in circulation, is secreted in the cranium and is drained out through ducts called epidural veins. The venous drainage system has inherent resistance to the flow. Pressure is developed inside the cranium, which is similar to a rigid compartment. Normally a pressure of 5-15 mm Hg, in excess of atmospheric pressure, is observed at different locations inside the cranium. Increase in Intra-Cranial Pressure (ICP) can be caused by change in CSF volume caused by cerebral tumors, meningitis, by edema of a head injury or diseases related to cerebral atrophy. Hence, efficient ways of monitoring ICP need to be developed. A sensor system and monitoring scheme has been discussed here. The system architecture consists of a membrane less piezoelectric pressure sensitive element, organic thin film transistor (OTFT) based signal transduction, and signal telemetry. The components were fabricated on flexible substrate and have been assembled using flip-chip packaging technology. Material science and fabrication processes, subjective to the device performance, have been discussed. Capability of the device in detecting pressure variation, within the ICP pressure range, is investigated and applicability of measurement scheme to medical conditions has been argued for. Also, applications of such a sensor-OTFT assembly for logic sensor switching and patient specific-secure monitoring system have been discussed.

Rai, Pratyush; Varadan, Vijay K.

2010-03-01

347

Response of the Saver Dipole Beam Tube to single-phase helium pressure  

SciTech Connect

One Energy Saver Dipole Beam Tube (No. MB 124211) was tested under static and pulsed pressure conditions. Under static pressure, permanent deformation started at about 125 psi and reached .006 inches across flats after 220 psi exposure. Final catastrophic collapse occurred at 325 psi. Pressure pulses of shape and duration approximating the single phase helium pressure during a full house quench had no effect on the tube (previously staticly pressurized to 220 psi) up to 285 psi and a slight yield effect at 305 psi. Repeated pulses at 305 psi appeared to cause little or no further yielding. When compared to static pressure effects the 305 psi pulse produced the same deflection as about 235 psi static pressure.

Biallas, G.; Barner, D.

1983-01-19

348

High-pressure optical studies  

SciTech Connect

High pressure experimentation may concern intrinsically high pressure phenomena, or it may be used to gain a better understanding of states or processes at one atmosphere. The latter application is probably more prevelant in condensed matter physics. Under this second rubric one may either use high pressure to perturb various electronic energy levels and from this pressure tuning characterize states or processes, or one can use pressure to change a macroscopic parameter in a controlled way, then measure the effect on some molecular property. In this paper, the pressure tuning aspect is emphasized, with a lesser discussion of macroscopic - molecular relationships. In rare earth chelates the efficiency of 4f-4f emission of the rare earth is controlled by the feeding from the singlet and triplet levels of the organic ligand. These ligand levels can be strongly shifted by pressure. A study of the effect of pressure on the emission efficiency permits one to understand the effect of ligand modification at one atmosphere. Photochromic crystals change color upon irradiation due to occupation of a metastable ground state. In thermochromic crystals, raising the temperature accomplishes the same results. For a group of molecular crystals (anils) at high pressure, the metastable state can be occupied at room temperature. The relative displacement of the energy levels at high pressure also inhibits the optical process. Effects on luminescence intensity are shown to be consistent. In the area of microscopic - molecular relationships, the effect of viscosity and dielectric properties on rates of non-radiative (thermal) and radiative emission, and on peak energy for luminescence is demonstrated. For systems which can emit from either of two excited states depending on the interaction with the environment, the effect of rigidity of the medium on the rate of rearrangement of the excited state is shown.

Drickamer, H.G.

1981-01-01

349

A hydrostatic pressure approach to cuffless blood pressure monitoring.  

PubMed

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

Shaltis, P; Reisner, A; Asada, H

2004-01-01

350

PSP Measurement of Stator Vane Surface Pressures in a High Speed Fan.  

National Technical Information Service (NTIS)

This paper presents measurements of static pressures on the stator vane suction side of a high-speed single stage fan using the technique of pressure sensitive paint (PSP). The paper illustrates development in application of the relatively new experimenta...

J. Lepicovsky

1998-01-01

351

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

352

In-shoe plantar pressure measurement and analysis system based on fabric pressure sensing array.  

PubMed

Spatial and temporal plantar pressure distributions are important and useful measures in footwear evaluation, athletic training, clinical gait analysis, and pathology foot diagnosis. However, present plantar pressure measurement and analysis systems are more or less uncomfortable to wear and expensive. This paper presents an in-shoe plantar pressure measurement and analysis system based on a textile fabric sensor array, which is soft, light, and has a high-pressure sensitivity and a long service life. The sensors are connected with a soft polymeric board through conductive yarns and integrated into an insole. A stable data acquisition system interfaces with the insole, wirelessly transmits the acquired data to remote receiver through Bluetooth path. Three configuration modes are incorporated to gain connection with desktop, laptop, or smart phone, which can be configured to comfortably work in research laboratories, clinics, sport ground, and other outdoor environments. A real-time display and analysis software is presented to calculate parameters such as mean pressure, peak pressure, center of pressure (COP), and shift speed of COP. Experimental results show that this system has stable performance in both static and dynamic measurements. PMID:20071266

Shu, Lin; Hua, Tao; Wang, Yangyong; Qiao Li, Qiao; Feng, David Dagan; Tao, Xiaoming

2010-01-12

353

Gravitational Collapse with Tangential Pressure  

NASA Astrophysics Data System (ADS)

Using the general formalism for spherical gravitational collapse developed in [P. S. Joshi and I. H. Dwivedi, Class. Quant. Grav. 16 (1999) 41; P. S. Joshi and R. Goswami, Phys. Rev. D 76 (2007) 084026], we investigate here the final fate of a spherical distribution of a matter cloud, where radial pressures vanish but tangential pressures are nonzero. Within this framework, firstly we examine the effect of introducing a generic small pressure in a well-known black hole formation process, which is that of an otherwise pressure-free dust cloud. The intriguing result we find is that a dust collapse that was going to a black hole final state could now go to a naked singularity final configuration, when arbitrarily small tangential pressures are introduced. The implications of such a scenario are discussed in some detail. Secondly, the approach here allows us to generalize the earlier results obtained on gravitational collapse with nonzero tangential pressure, in the presence of a nonzero cosmological constant. Finally, we discuss the genericity of black hole and naked singularity formation in collapse with nonzero tangential pressure. The treatment here gives a unified and complete picture on collapse final states, in terms of black hole and naked singularity formation, generalizing the earlier results obtained for this class of collapse models. Thus the role of tangential stresses towards determining collapse end-states emerges in a straightforward and transparent manner in our treatment.

Malafarina, Daniele; Joshi, Pankaj S.

354

Optical calibration of pressure sensors for high pressures and temperatures  

SciTech Connect

We present the results of Raman-scattering measurements of diamond ({sup 12}C) and of cubic boron nitride, and fluorescence measurements of ruby, Sm:yttrium aluminum garnet (Sm:YAG), and SrB{sub 4}O{sub 7}:Sm{sup 2+} in the diamond anvil cell at high pressures and temperatures. These measurements were accompanied by synchrotron x-ray-diffraction measurements on gold. We have extended the room-temperature calibration of Sm:YAG in a quasihydrostatic regime up to 100 GPa. The ruby scale is found to systematically underestimate pressure at high pressures and temperatures compared with all the other sensors. On this basis, we propose an alternative high-temperature ruby pressure scale that is valid to at least 100 GPa and 850 K.

Goncharov, Alexander F.; Zaug, Joseph M.; Crowhurst, Jonathan C.; Gregoryanz, Eugene [Lawrence Livermore National Laboratory, 7000 East Avenue, Livermore, California 94551 (United States); Geophysical Laboratory, Carnegie Institution of Washington, 5251 Broad Branch Road, Northwest, Washington DC 20015 (United States)

2005-05-01

355

Dorsomedial/Perifornical Hypothalamic Stimulation Increases Intraocular Pressure, Intracranial Pressure, and the Translaminar Pressure Gradient  

PubMed Central

Purpose. Intraocular pressure (IOP) fluctuation has recently been identified as a risk factor for glaucoma progression. Further, decreases in intracranial pressure (ICP), with postulated increases in the translaminar pressure gradient across the lamina cribrosa, has been reported in glaucoma patients. We hypothesized that circadian fluctuations in IOP and the translaminar pressure gradient are influenced, at least in part, by central autonomic regulatory neurons within the dorsomedial and perifornical hypothalamus (DMH/PeF). This study examined whether site-directed chemical stimulation of DMH/PeF neurons evoked changes in IOP, ICP, and the translaminar pressure gradient. Methods. The GABAA receptor antagonist bicuculline methiodide (BMI) was stereotaxically microinjected into the DMH/PeF region of isoflurane-anesthetized male Sprague-Dawley rats (n = 19). The resulting peripheral cardiovascular (heart rate [HR] and mean arterial pressure [MAP]), IOP, and ICP effects were recorded and alterations in the translaminar pressure gradient calculated. Results. Chemical stimulation of DMH/PeF neurons evoked significant increases in HR (+69.3 ± 8.5 beats per minute); MAP (+22.9 ± 1.6 mm Hg); IOP (+7.1 ± 1.9 mm Hg); and ICP (+3.6 ± 0.7 mm Hg) compared with baseline values. However, the peak IOP increase was significantly delayed compared with ICP (28 vs. 4 minutes postinjection), resulting in a dramatic translaminar pressure gradient fluctuation. Conclusions. Chemical stimulation of DMH/PeF neurons evokes substantial increases in IOP, ICP, and the translaminar pressure gradient in the rat model. Given that the DMH/PeF neurons may be a key effector pathway for circadian regulation of autonomic tone by the suprachiasmatic nucleus, these findings will help elucidate novel mechanisms modulating circadian fluctuations in IOP and the translaminar pressure gradient.

Samuels, Brian C.; Hammes, Nathan M.; Johnson, Philip L.; Shekhar, Anantha; McKinnon, Stuart J.; Allingham, R. Rand

2012-01-01

356

Can skin surface pressure under a cast reveal intracompartmental pressure?  

Microsoft Academic Search

Although monitoring intracompartmental pressure (IP) under a cast is very important, it is not possible to measure it in\\u000a every patient undergoing cast treatment. This study aims to answer the question of whether skin surface pressure (SSP) under\\u000a a cast can reveal IP. A plaster cast was applied to a sculpted inflatable forearm model with dorsal and volar compartments.\\u000a SSP

M. Murad Uslu; Alpaslan Apan

2000-01-01

357

Self pressuring HTP feed systems  

SciTech Connect

Hydrogen peroxide tanks can be pressurized with decomposed HTP (high test hydrogen peroxide) originating in the tank itself. In rocketry, this offers the advantage of eliminating bulky and heavy inert gas storage. Several prototype self-pressurizing HTP systems have recently been designed and tested. Both a differential piston tank and a small gas-driven pump have been tried to obtain the pressure boost needed for flow through a gas generator and back to the tank. Results include terrestrial maneuvering tests of a prototype microsatellite, including warm gas attitude control jets.

Whitehead, J.

1999-10-14

358

Intracranial pressure monitoring: why monitor?  

PubMed

Evidence suggests that the mortality and morbidity of acquired brain injury could be reduced if clinicians used an aggressive intracranial pressure guided approach to care. Despite nearly 50 years of evidence that intracranial pressure monitoring benefits patient care, only about half of the patients who could benefit are monitored. Some clinicians express concerns regarding risks such as bleeding, infections, and inaccuracy of the technology. Others cite cost as the reason. This article discusses the risks and benefits of intracranial pressure monitoring and the current state of evidence of why patients should be monitored. PMID:16269892

March, Karen

359

Electrokinetic high pressure hydraulic system  

SciTech Connect

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

360

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.

Virtanen; Kari (Asheville, NC)

2008-07-15

361

Melting of metals under pressure  

NASA Astrophysics Data System (ADS)

Lindemann's formula of melting is extended in terms of bulk modulus and Grüneisen parameter to study the pressure dependence of melting temperature, Tm(P) of metals. The formalism is applied to study Tm(P) of noble and transition metals, di-, tri- and tetravalent (Ag, Au, Cu, Mn, Mg, Zn, CD, In, Pb and Al) metals over a wide range of pressures up to 12 GPa. The computed melting temperatures of the metals under pressure using our semi-empirical relation is in good agreement with the experimental data.

Arafin, S.; Singh, R. N.; George, A. K.

2013-06-01

362

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

363

Thermionic fuel element pressure vessel  

SciTech Connect

This patent describes a thermionic convertor core. It comprises an array of thermionic fuel elements wherein each fuel element comprises: a nuclear fuel heat source; an emitter thermally coupled to and generally surrounding the heat source; a collector in a spaced relationship from and generally surrounding the emitter; and a pressure vessel generally surrounding the collector; and, wherein an axial cross-section of each pressure vessel surrounding a collector has generally the shape of a polygon and the pressure vessels are arranged in physical contact polygon side to polygon side.

Kennel, E.B.; Perry, M.S.; Leland, J.E.

1991-08-13

364

Characterization of the pressure-induced intermediate and unfolded state of red-shifted green fluorescent protein--a static and kinetic FTIR, UV/VIS and fluorescence spectroscopy study.  

PubMed

The green fluorescence proteins (GFP) are widely used as reporters in molecular and cell biology. For their use it in high-pressure microbiology and biotechnology studies, their structural properties, thermodynamic parameters and stability diagrams have to be known. We investigated the pressure stability of the red-shifted green fluorescent protein (rsGFP) using Fourier-transform infrared spectroscopy, fluorescence and UV/Vis spectroscopy. We found that rsGFP does not unfold up to approximately 9kbar at room temperature. Its unique three-dimensional structure is held responsible for the high-pressure stability. At higher temperatures, its secondary structure collapses below 9kbar (e.g. the denaturation pressure at 58 degrees C is 7.8kbar). The analysis of the IR data shows that the pressure-denatured state contains more disordered structures at the expense of a decrease of intramolecular beta-sheets. As indicated by the large volume change of DeltaV degrees (u) approximately -250(+/-50)mlmol(-1) at 58 degrees C, this highly cooperative transition can be interpreted as a collapse of the beta-can structure of rsGFP. For comparison, the temperature-induced unfolding of rsGFP has also been studied. At high temperature (T(m)=78 degrees C), the unfolding resulted in the formation of an aggregated state. Contrary to the pressure-induced unfolding, the temperature-induced unfolding and aggregation of GFP is irreversible. From the FT-IR data, a tentative p,T-stability diagram for the secondary structure collapse of GFP has been obtained. Furthermore, changes in fluorescence and absorptivity were found which are not correlated to the secondary structural changes. The fluorescence and UV/Vis data indicate smaller conformational changes in the chromophore region at much lower pressures ( approximately 4kbar) which are probably accompanied by the penetration of water into the beta-can structure. In order to investigate also the kinetics of this initial step, pressure-jump relaxation experiments were carried out. The partial activation volumes observed indicate that the conformational changes in the chromophore region when passing the transition state are indeed rather small, thus leading to a comparably small volume change of -20 ml mol(-1) only. The use of the chromophore absorption and fluorescence band of rsGFP in using GFP as reporter for gene expression and other microbiological studies under high pressure conditions is thus limited to pressures of about 4kbar, which still exceeds the pressure range relevant for studies in vivo in micro-organisms, including piezophilic bacteria from deep-sea environments. PMID:12860135

Herberhold, H; Marchal, S; Lange, R; Scheyhing, C H; Vogel, R F; Winter, R

2003-07-25

365

Burst failure load of composite pressure vessels  

Microsoft Academic Search

In this study, optimal angle-ply orientations of symmetric and antisymmetric [?\\/??]s shells designed for maximum burst pressure were examined. Burst pressure of filament wound composite pressure vessels under alternating pure internal pressure was investigated. The study deals with the influences of temperature and winding angle on filament wound composite pressure vessels. Finite element method and experimental approaches were employed to

Aziz Onder; Onur Sayman; Tolga Dogan; Necmettin Tarakcioglu

2009-01-01

366

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

367

Seven-Hole Pressure Probe.  

National Technical Information Service (NTIS)

This paper documents recent and past developments with respect to the seven-hole pressure probe. Included are discussions on probe design, construction, calibration, and measurement capabilities. The effects on probe measurements in shear flows, as well a...

L. Reed J. D. Mattingly F. M. Jonas

1984-01-01

368

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

369

Brillouin Scattering at High Pressures.  

National Technical Information Service (NTIS)

Technical advances which have made Brillouin scattering a useful tool in high pressure diamond anvil cell (DAC) studies, viz. multipassing and tandem operation of Fabry-Perot interferometers, are reviewed. Experimental aspects, such as allowed scattering ...

M. Grimsditch A. Polian

1988-01-01

370

Potassium and High Blood Pressure  

MedlinePLUS

A diet that includes natural sources of potassium is important in controlling blood pressure because potassium lessens the effects of sodium. The recommended daily intake of potassium for an average adult ...

371

Pressure compensated flow control valve  

DOEpatents

The invention is an air flow control valve which is capable of maintaining a constant flow at the outlet despite changes in the inlet or outlet pressure. The device consists of a shell assembly with an inlet chamber and outlet chamber separated by a separation plate. The chambers are connected by an orifice. Also located within the inlet chamber is a port controller assembly. The port controller assembly consists of a differential pressure plate and port cap affixed thereon. The cap is able to slide in and out of the orifice separating the inlet and outlet chambers. When the pressure differential is sufficient, the differential pressure plate rises or falls to maintain a constant air flow. Movement of the port controller assembly does not require the use of seals, diaphragms, tight tolerances, bushings, bearings, hinges, guides, or lubricants.

Minteer, Daniel J. (West Richland, WA)

1999-01-01

372

[Nursing care of pressure ulcers].  

PubMed

The definition of a pressure ulcer remains very academic. It results from tissue necrosis following ischemia through prolonged arteriolar constriction between two hard surfaces progressing in stages. The nursing care and the use of dressings are therefore adapted to each stage. Today, the treatment of pressure ulcers is complex due to the large number of categories of dressings available. Moreover, the choice of the dressing must take into account the specificities of elderly patients. However, certain basic principles remain essential. PMID:23785859

Hautin, Pascale

373

High-pressure creep tests  

Microsoft Academic Search

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.

S. Bhattacharyya; J. Lamoureux; C. Hales

1986-01-01

374

Electrochemical studies at high pressure  

SciTech Connect

This research has dealt with the development and application of a methodology that permits electrochemical measurements at high pressure. The initial efforts focused on the design and construction of an electrochemical cell functional at hydrostatic pressures as high as 10 kbar. This cell was equipped with an Ag/AgCl/KCl (0.1M) reference electrode which provides reliable control of the potential at all pressures. The potential of this reference electrode can be considered to be constant with pressure. Measurements of formal potentials (E[degrees][prime]) of several transition-metal complexes vs the Ag/AgCl electrode rendered volumes of reactions whose magnitudes support the prediction of the negligible pressure dependence of the reference electrode. The main systems that have been investigated at high pressure are surface-modified electrodes. The author studied the effect of compression on the dynamics of charge transport in quaternized poly(4-vinylpyridine) (QPVP) films placed on gold electrodes, loaded with potassium ferricyanide, and equilibrated in potassium nitrate. Pressure accomplished the continuous change in the structure of the polymer network. This change causes a pronounced restriction in the propagation of charge and in the motion of mass. This high-pressure methodology has also allowed the spatial characterization of electron transfer events taking place between a gold electrode and ferrocene molecules covalently attached to the end of 1-undodecanethiol chains self-assembled on the electrode surface. The volumes of reaction and activation for the oxidation process are both positive, indicating that a volume expansion is associated with the formation of ferricinium. A model is proposed in which the creation of a vacancy in the self-assembled monolayer, for the accommodation of the ferricinium ion or a charge-compensating anion, is coupled with the electron transfer step.

Cruanes, M.T.

1993-01-01

375

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

376

Atmospheric-pressure plasma jet  

Microsoft Academic Search

Atmospheric-pressure plasma jet. A .gamma.-mode, resonant-cavity plasma discharge that can be operated at atmospheric pressure and near room temperature using 13.56 MHz rf power is described. Unlike plasma torches, the discharge produces a gas-phase effluent no hotter than 250.degree. C. at an applied power of about 300 W, and shows distinct non-thermal characteristics. In the simplest design, two concentric cylindrical

Selwyn; Gary S

1999-01-01

377

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

378

An oxygen partial pressure sensor  

Microsoft Academic Search

The oxygen partial pressure of the gas mixture man breathes is an important measurement. A sensor is described which makes\\u000a use of the reaction of oxygen with hydrogen in the presence of catalytic platinum to produce water and electrical energy.\\u000a The voltage output is a direct function of the oxygen partial pressure. Performance data are presented and a package design

H. Warner; Valley Forge

1963-01-01

379

Measuring the pressure in ultrahigh-pressure mercury arcs  

NASA Astrophysics Data System (ADS)

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 ?? of the 546 nm Hg line while varying p and also the lamp current I and voltage U. The data define a function p(??,I,U) that will deliver p to better than 3% from simple measurements of ??, 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.

2009-09-01

380

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

381

Pressure variations during ultra-high pressure metasomatism?  

NASA Astrophysics Data System (ADS)

Incomplete reactions or apparent disequilibrium between minerals in metamorphic rocks from high pressure (HP) and ultra-high pressure (UHP) terrains are commonly observed in field and thin section. Here we show an example of a peridotitic body enclosed in migmatitic felsic Proterozoic gneiss at the Svartberget locality in the northernmost UHP terrain of the Western Gneiss Region (WGR) in Western Norway. The WGR represents the basement of Baltica which became metamorphosed during the Caledonian Orogeny. In the highest grade parts of the WGR metamorphic temperatures were between 600-800 °C for several Ma, pressures reached the diamond stability field, fluids were available and yet well known pressure sensitive reactions such as from spinel- to garnet-peridotite went only locally to completion in the studied peridotite. Previously reported field observations, major, trace and isotope geochemistry, geochronology, mineral-chemistry and textures suggest that this peridotite body became metasomatised by supercritical fluids from the host rock gneiss during the Caledonian Orogeny. Contrasting pressure estimates, incomplete reactions and preserved compositional gradients in minerals from this body may indicate very rapid exhumation, very sluggish kinetics of diffusion, metasomatically disturbed equilibrium at low temperatures or a combination of the three. These possibilities call for a re-evaluation of existing methods in geothermobarometry. Alternatively we may consider that pressure variations existed from the grain up to the outcrop scale during the metasomatism of the peridotite at UHP conditions. The mechanical responses to volume changes that are involved in chemical reactions in rocks may control the progress of reactions significantly (Schmid et al.1, 2009). Our main results, obtained from numerical modelling, show that pressure variations may be generated, and maintained on the geological time scale, as a result of the mechanical response of the rocks during melting reactions in confined space.

Vrijmoed, J. C.; Podladchikov, Y. Y.

2009-04-01

382

Hazards in high pressure systems  

SciTech Connect

The High Pressure Systems Committee (HPSC) of the American Society of Mechanical Engineers is writing a set of rules and guides which will eventually be approved for treatment of safety concerns in high pressure operations. An introductory section of the proposed standard is being written to describe the hazards in high pressure. This paper is an edited version of the early draft of that section which is numbered 2000. Taking Section 2000 out of context (separately printing it from the remainder of the proposed standard) poses a possible misunderstanding in that high pressure is not necessarily synonymous with a lack of safety. There are many high pressure systems in operation with very acceptable safety records. However, when the potential for damage is great, it becomes more essential that safety be comprehensively engineered and practiced. Everyone concerned should be aware to some degree of the dangers that could happen in such operations. This paper is written in an attempt to share the concerns (appraisal of the risks) that members of the HPSC have for high pressure as interpreted and edited by this author. 22 refs.

Priddy, T.G.

1985-08-01

383

[Weight reduction and blood pressure].  

PubMed

112 patients (78 hypertensives and 34 normotensives) received guidance from a specially trained dietitian on a low-calorie diet. During a mean control period of 10.8 months with a comparable number of visits in each group, the following results were observed: 51% (n = 40) of hypertensive patients achieved a significant weight reduction. In 28% (n = 22) antihypertensive medication was constant and in 23% (n = 18) this medication was reduced or withdrawn. 37% (n = 29) showed no significant changes in body weight or blood pressure and 12% (n = 9) dropped out. In 22 patients a weight reduction of 8.5 kg with a significant fall in blood pressure from 156/99 to 137/90 mm Hg was observed. In 18 hypertensives a weight reduction of 8.5 kg allowed reduction or withdrawal of antihypertensive medication with blood pressure remaining unchanged (139/91 vs. 135/90 mm Hg). Similar results were achieved in 34 normotensive obese patients: 59% (n = 20) had significant weight reduction, 32% (n = 11) no significant reduction in weight or blood pressure, and 9% (n = 3) dropped out. 20 patients with a reduction of 9 kg showed a significant fall in blood pressure from 132/84 to 123/80 mm Hg. The results demonstrate the favourable effect of weight reduction on blood pressure. The time-consuming nature of the frequent and intensive checks should, however, be borne in mind. PMID:7063823

Greminger, P; Studer, A; Lüscher, T; Mutter, B; Grimm, J; Siegenthaler, W; Vetter, W

1982-01-23

384

Heme protein fluorescence versus pressure.  

PubMed Central

Fluorescence spectra of several ferric heme proteins have been measured vs. pressure to 6,000 bars. Sperm whale myoglobin (SW Mb), Aplysia myoglobin, leghemoglobin (Lb), and cytochrome P450 all show excitation and emission spectra characteristic of tryptophan in proteins with peak emission at 330-340 nm. At one bar, the fluorescence is weak due to energy transfer to the heme group, which makes the yield a sensitive probe of protein unfolding at high pressure. After an initial decrease of a few percent per kbar, the protein shows a large increase in fluorescence at high pressure. The increase is pH dependent and the results indicate that several high pressure states occur. For SW Mb at 15 degrees C an increase of a factor of 20 occurs with midpoint at 2,000 bars at pH 5 and is only partially reversible, while the increase at pH 7 occurs at 4,000 bars and is only half as large and is completely reversible. Aplysia Mb and Lb show a similar effect, but unfold at a higher pressure than SW Mb. P450 also shows a transition to a state of higher fluorescence, but the transition in this case is irreversible as a stable form, P420, is formed. The fluorescence intensity measurements permit an estimation of the increase in the TRY-heme distance in the high pressure state.

Marden, M C; Hui Bon Hoa, G; Stetzkowski-Marden, F

1986-01-01

385

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

386

Effect of the Venous Pressure to the Blood Pressure Signals Measured by the Electronic Palpation Method.  

National Technical Information Service (NTIS)

This paper describes the venous pressure effect to blood pressure signals measured by the electronic palpation method. It was shown, that in 52 percent of blood pressure measurements made with inflating cuff the linear increase in venous blood pressure wa...

E. I. Vieri-Gashi H. S. Sorvoja R. A. Myllyla S. M. Nissila M. Sorvisto

2001-01-01

387

49 CFR 192.621 - Maximum allowable operating pressure: High-pressure distribution systems.  

Code of Federal Regulations, 2010 CFR

...2009-10-01 false Maximum allowable operating pressure: High-pressure distribution systems. 192.621 Section 192...Operations § 192.621 Maximum allowable operating pressure: High-pressure distribution systems. (a) No...

2009-10-01

388

49 CFR 192.621 - Maximum allowable operating pressure: High-pressure distribution systems.  

Code of Federal Regulations, 2010 CFR

...2010-10-01 false Maximum allowable operating pressure: High-pressure distribution systems. 192.621 Section 192...Operations § 192.621 Maximum allowable operating pressure: High-pressure distribution systems. (a) No...

2010-10-01

389

Evaluation of advanced pressure sensor technology.  

National Technical Information Service (NTIS)

New pressure sensing technology is being evaluated to improve pressure sensor performance for utility applications. Existing pressure sensors do not have accuracies required to be compatible with distributed control systems (DCS). The most common type of ...

J. M. Weiss R. L. Shepard

1992-01-01

390

46 CFR 169.249 - Pressure vessels.  

Code of Federal Regulations, 2010 CFR

...2009-10-01 2009-10-01 false Pressure vessels. 169.249 Section...SECURITY (CONTINUED) NAUTICAL SCHOOLS SAILING SCHOOL VESSELS Inspection and Certification... Inspections § 169.249 Pressure vessels. Pressure...

2009-10-01

391

46 CFR 169.249 - Pressure vessels.  

Code of Federal Regulations, 2012 CFR

...2012-10-01 2012-10-01 false Pressure vessels. 169.249 Section...SECURITY (CONTINUED) NAUTICAL SCHOOLS SAILING SCHOOL VESSELS Inspection and Certification... Inspections § 169.249 Pressure vessels. Pressure...

2012-10-01

392

46 CFR 169.249 - Pressure vessels.  

Code of Federal Regulations, 2011 CFR

...2011-10-01 2011-10-01 false Pressure vessels. 169.249 Section...SECURITY (CONTINUED) NAUTICAL SCHOOLS SAILING SCHOOL VESSELS Inspection and Certification... Inspections § 169.249 Pressure vessels. Pressure...

2011-10-01

393

46 CFR 169.249 - Pressure vessels.  

Code of Federal Regulations, 2010 CFR

...2010-10-01 2010-10-01 false Pressure vessels. 169.249 Section...SECURITY (CONTINUED) NAUTICAL SCHOOLS SAILING SCHOOL VESSELS Inspection and Certification... Inspections § 169.249 Pressure vessels. Pressure...

2010-10-01

394

BEAM INDUCED PRESSURE RISE IN RHIC.  

SciTech Connect

Beam induced pressure rise in RHIC warm sections is one of the machine luminosity limits. The RHIC electron cloud and the beam transition pressure rise are discussed. Countermeasures and studies for RHIC pressure rise and RHIC upgrade are reported.

ZHANG, S.Y.; ALESSI, J.; BAI, M.; ET AL.

2005-05-16

395

Pressure ulcers - what to ask your doctor  

MedlinePLUS

Pressure ulcers are also called bedsores, or pressure sores. They can form when your skin and soft tissue press ... damaged or die. When this happens, a pressure ulcer may form. Below are some questions you may ...

396

Atmospheric-Pressure Plasma Process and Applications.  

National Technical Information Service (NTIS)

This paper provides a general discussion of atmospheric-pressure plasma generation, processes, and applications. There are two distinct categories of atmospheric-pressure plasmas: thermal and nonthermal. Thermal atmospheric-pressure plasmas include those ...

P. Kong

2006-01-01

397

46 CFR 154.452 - External pressure.  

Code of Federal Regulations, 2012 CFR

...acceleration and hull deflection, and the local effect of external and internal pressure. P4 =0, or the external pressure from the head of water from any portion of the pressure vessel on exposed...

2012-10-01

398

46 CFR 154.452 - External pressure.  

Code of Federal Regulations, 2010 CFR

...acceleration and hull deflection, and the local effect of external and internal pressure. P4 =0, or the external pressure from the head of water from any portion of the pressure vessel on exposed...

2010-10-01

399

46 CFR 154.452 - External pressure.  

Code of Federal Regulations, 2011 CFR

...acceleration and hull deflection, and the local effect of external and internal pressure. P4 =0, or the external pressure from the head of water from any portion of the pressure vessel on exposed...

2011-10-01

400

46 CFR 154.452 - External pressure.  

Code of Federal Regulations, 2010 CFR

...acceleration and hull deflection, and the local effect of external and internal pressure. P4 =0, or the external pressure from the head of water from any portion of the pressure vessel on exposed...

2009-10-01

401

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

402

Pressure Ulcers and Nutritional Implications. (Video).  

National Technical Information Service (NTIS)

This satellite broadcast will define pressure ulcers, describe the etiology of pressure ulcers, identify the effective prevention measures, and explain the rational for comprehensive nutrition intervention.

1998-01-01

403

Clinical Evaluation of Tracheal Pressure Estimation from the Endotracheal Tube Cuff Pressure  

Microsoft Academic Search

Objective. Air flow through an endotracheal tube causes a pressure drop across the tube. This pressure drop creates a difference between air pressure measured in the trachea and the pressure measured in the breathing circuit, which can lead to errors when calculating pulmonary mechanics and when setting ventilators. We have developed a method of estimating tracheal pressure from the pressure

Nicholas A. Wilder; Joseph Orr; Dwayne Westenskow

1998-01-01

404

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

405

High pressure synthesis gas conversion. Task 3: High pressure profiles  

SciTech Connect

The purpose of this research project was to build and test a high pressure fermentation system for the production of ethanol from synthesis gas. The fermenters, pumps, controls, and analytical system were procured or fabricated and assembled in our laboratory. This system was then used to determine the effects of high pressure on growth and ethanol production by C. 1jungdahlii. The limits of cell concentration and mass transport relationships were found in CSTR and immobilized cell reactors (ICR). The minimum retention times and reactor volumes were found for ethanol production in these reactors.

Not Available

1993-05-01

406

Electrochemical cell pressure relief devices  

SciTech Connect

A unitary end wall for an electrochemical cell container is described. The end wall comprises a central portion, encompassing the center of the wall, a peripheral portion surrounding the central portion, bridge means for connecting the central portion to the peripheral portion, one or more curved lines of frangibility and one or more pressure relief tabs remote from the center of the wall. Each pressure relief tab is bounded by one of the curved lines of frangibility extending only partially around the tab. The wall is substantially devoid of wrinkles or scores other than the one or more curved lines of frangibility. The wall is adapted to fracture along each line of frangibility upon exposure to a pressure above a predetermined limit so that each pressure relief tab can bend away from the remainder of the wall and provide an opening for relief of the pressure remote from the center of the wall. The bridge means is operative to retain the central portion in place relative to the peripheral portion upon fracture of the wall along the one or more lines of frangibility.

Marchak, G.E.

1988-02-02

407

Dynamic pressures in porous media  

NASA Astrophysics Data System (ADS)

Understanding the relationship between fluid pressures and water content (saturation) in soils or other porous media can be important in a wide range of practical areas, including oil recovery, infiltration and flooding during extreme weather events, and environmental remediation. The relationship between fluid pressures and saturation in porous media has been reported to be dynamic—to depend on the flow rate as saturation changes. However, previous studies designed to understand the dynamic component of this relationship have been highly contradictory. To learn more, Hou et al. conducted experiments to quantify the relationship between pressure and rate of saturation change using a small-volume system with highly characterized fluid selective microsensors. Their analyses corrected for two often-overlooked experimental artifacts: gas pressure gradients and sensor response rate. When the researchers applied these corrections, they found that the dependence of pressure on the rate of saturation change may be much less significant than previously thought. (Water Resources Research, doi:10.1029/2012WR012434, 2012)

Balcerak, Ernie

2012-12-01

408

Low blood pressure, low mood?  

PubMed Central

OBJECTIVE--To determine whether a set of physical symptoms is associated with low blood pressure and to investigate the possible role of psychological factors in their occurrence. DESIGN--Analysis of data collected by questionnaire and physical screening from the first phase of the Whitehall II study, a cohort study of an employed population. SETTING--23 civil service departments in London. SUBJECTS--10,314 male and female London based civil servants aged between 35 and 55. MAIN OUTCOME MEASURES--Symptoms of dizziness-giddiness and unexplained tiredness; psychological functioning as measured by the 30 item general health questionnaire in which the response "no more than usual" to an item about disease was scored as indicating chronic illness. RESULTS--Dizziness-giddiness in men and unexplained tiredness in both men and women were significantly related to low systolic blood pressure. There was a highly significant inverse relation between general health questionnaire score and systolic blood pressure for both men and women, which persisted after controlling for potentially confounding variables, including age, body mass index, drug treatment, physical illness, and exercise. This association of low blood pressure with physical symptoms was no longer significant when general health questionnaire score was controlled for. CONCLUSIONS--There seems a strong relation between low systolic blood pressure and minor psychological dysfunction. Associated physical symptoms seem to be secondary to the primary disturbance in mental state.

Pilgrim, J. A.; Stansfeld, S.; Marmot, M.

1992-01-01

409

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

410

Melting of Ice under Pressure  

SciTech Connect

The melting of ice under pressure is investigated with a series of first principles molecular dynamics simulations. In particular, a two-phase approach is used to determine the melting temperature of the ice-VII phase in the range of 10 to 50 GPa. Our computed melting temperatures are consistent with existing diamond anvil cell experiments. We find that for pressures between 10 to 40 GPa, ice melts as a molecular solid. For pressures above {approx}45 GPa there is a sharp increase in the slope of the melting curve due to the presence of molecular dissociation and proton diffusion in the solid, prior to melting. The onset of significant proton diffusion in ice-VII as a function of increasing temperature is found to be gradual and bears many similarities to that of a type-II superionic solid.

Schwegler, E; Sharma, M; Gygi, F; Galli, G

2008-07-31

411

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

412

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

413

High-pressure creep tests  

SciTech Connect

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. 13 references.

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

1986-07-01

414

Pressurized-fluid-operated engine  

SciTech Connect

This patent describes a pressurized-fluid-operated reciprocating engine for providing output power by use of a pressurized gas that expands within the engine without combustion. It comprises: an engine block having a plurality of cylinders within which respective pistons are reciprocatable to provide a rotary power output; gas inlet means connected with the engine block for introducing a pressurized gas into the respective cylinders in a predetermined, timed relationship to provide a smooth power output from the engine; gas outlet means connected with the engine block for conveying exhaust gas from the respective cylinders after the gas expanded to move the pistons within the cylinders; and recirculation means extending between the inlet means and the outlet means for recirculation a predetermined quantity of exhaust gas. The recirculation means including ejector means for drawing exhaust gas into the recirculation means.

Holleyman, J.E.

1990-01-30

415

High pressure melting of lithium.  

PubMed

The melting curve of lithium between ambient pressure and 64 GPa is measured by detection of an abrupt change in its electrical resistivity at melting and by visual observation. Here we have used a quasi-four-point resistance measurement in a diamond anvil cell and measured the resistance of lithium as it goes through melting. The resistivity near melting exhibits a well documented sharp increase which allowed us to pinpoint the melting transition from ambient pressure to 64 GPa. Our data show that lithium melts clearly above 300 K in all pressure regions and its melting behavior adheres to the classical model. Moreover, we observed an abrupt increase in the slope of the melting curve around 10 GPa. The onset of this increase fits well to the linear extrapolation of the lower temperature bcc-fcc phase boundary. PMID:23215297

Schaeffer, Anne Marie J; Talmadge, William B; Temple, Scott R; Deemyad, Shanti

2012-11-02

416

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

417

Melting of ice under pressure.  

PubMed

The melting of ice under pressure is investigated with a series of first-principles molecular dynamics simulations. In particular, a two-phase approach is used to determine the melting temperature of the ice-VII phase in the range of 10-50 GPa. Our computed melting temperatures are consistent with existing diamond anvil cell experiments. We find that for pressures between 10 and 40 GPa, ice melts as a molecular solid. For pressures above approximately 45 Gpa, there is a sharp increase in the slope of the melting curve because of the presence of molecular dissociation and proton diffusion in the solid before melting. The onset of significant proton diffusion in ice-VII as a function of increasing temperature is found to be gradual and bears many similarities to that of a type-II superionic solid. PMID:18809909

Schwegler, Eric; Sharma, Manu; Gygi, François; Galli, Giulia

2008-09-22

418

The High Pressure Nervous Syndrome and Other High Pressure Effects.  

National Technical Information Service (NTIS)

Many of the problems of exposing man to a high pressure environment depend overtly on the properties of gases in the gaseous phase--such as the various squeezes, voice distortion, thermal effects of helium, density effects, and decompression sickness. Oth...

T. C. Schmidt R. W. Hamilton

1973-01-01

419

Population Pressures Abroad and Immigration Pressures at Home.  

ERIC Educational Resources Information Center

This report discusses population trends abroad and their relation to immigration pressures and policies in the United States. The following sections are included: (1) "Two Major Waves of Immigration"; (2) "The U.S.--A Major Host Nation for Permanent Immigrants"; (3) "Changing Sources of Immigrants to the United States"; (4) "Current and Future…

Population Crisis Committee, Washington, DC.

420

Focal ischaemic normal pressure glaucoma versus high pressure glaucoma  

Microsoft Academic Search

In a total group of 130 patients with Normal Pressure Glaucoma (NPG) twenty-six were classified as Focal Ischaemic NPG (FINPG). This subgroup has a typical defect at the disc with a comparable visual field defect in the corresponding half of the visual field. Visual field defects are more often seen in the upper than the lower half of the visual

H. Caroline Geijssen; Erik L. Greve

1990-01-01

421

Arterial Pressure Monitoring in Mice  

PubMed Central

The use of mice for the evaluation and study of cardiovascular pathophysiology is growing rapidly, primarily due to the relative ease for developing genetically engineered mouse models. Arterial pressure monitoring is central to the evaluation of the phenotypic changes associated with cardiovascular pathology and interventions in these transgenic and knockout models. There are four major techniques for measuring arterial pressure in the mouse: tail cuff system, implanted fluid filled catheters, Millar catheters and implanted telemetry systems. Here we provide protocols for their use and discuss the advantages and limitations for each of these techniques .

Zhao, Xin; Ho, David; Gao, Shumin; Hong, Chull; Vatner, Dorothy E.; Vatner, Stephen F.

2011-01-01

422

Microplasma jet at atmospheric pressure  

SciTech Connect

A nitrogen microplasma jet operated at atmospheric pressure was developed for treating thermally sensitive materials. For example, the plasma sources in treatment of vulnerable biological materials must operate near the room temperature at the atmospheric pressure, without any risk of arcing or electrical shock. The microplasma jet device operated by an electrical power less than 10 W exhibited a long plasma jet of about 6.5 cm with temperature near 300 K, not causing any harm to human skin. Optical emission measured at the wide range of 280-800 nm indicated various reactive species produced by the plasma jet.

Hong, Yong Cheol; Uhm, Han Sup [Department of Molecular Science and Technology, Ajou University, San 5, Wonchon-Dong, Youngtong-Gu, Suwon 443-749 (Korea, Republic of)

2006-11-27

423

Pressure measurement on an uneven and ablating surface  

Microsoft Academic Search

The feasibility of static pressure measurement through ablative materials exposed to an extreme hot-flow environment was investigated in an electric-arc tunnel facility. Pressure measurements were taken through carbon-phenolic and Teflon sample materials and compared with a reference measurement through a nonablating wall, simultaneously subjected to the same test conditions. The average deviations from the reference values were from 2% to

Aharon Nabi; Menashe Barak

1989-01-01

424

Pressure Pulse Measurements Using Optical Hydrophone Principles  

Microsoft Academic Search

Pressure pulses are used in extracorporeal lithotripsy, pain therapy and other medical applications. Typical lithotripter pulses reach positive pressure amplitudes of ca. 20 to more than 100 MPa and negative pressures of -5 to more than -20 MPa, depending on the focusing properties and energy settings of the source. The IEC standard 61846, which defines the acoustic parameters of pressure

Friedrich Ueberle; Abtin Jamshidi-Rad

2011-01-01

425

The major pressure oscillation, 1875 to 1960  

Microsoft Academic Search

Pressure anomaly maps for the world for different periods have been constructed from barometric information received as a result of international appeals. Maps of changes by 5-year periods have been shown to reflect a pressure see-saw between West Greenland and the Indian Ocean. The sign of this pattern is defined by the «pressure parameter», approximately the reversed pressure in the

D. J. Schove

1961-01-01

426

The major pressure oscillation, 1875 to 1960  

Microsoft Academic Search

Summary Pressure anomaly maps for the world for different periods have been constructed from barometric information received as a result of international appeals. Maps of changes by 5-year periods have been shown to reflect a pressure see-saw between West Greenland and the Indian Ocean. The sign of this pattern is defined by the «pressure parameter», approximately the reversed pressure in

D. J. Schove

1961-01-01

427

Emotion recognition based on pressure sensor keyboards  

Microsoft Academic Search

This paper describes a new approach to emotion recognition based on pressure sensor keyboards. The pressure sensor keyboard is a new product that occurs in the market recently, which produces a pressure sequence when keystroke occurs. The analysis of the pressure sequence should be a novel research area. It has been used for identity verification in our previous research. In

Hai-Rong Lv; Zhong-Lin Lin; Wen-Jun Yin; Jin Dong

2008-01-01

428

Determination of Secondary Encasement Pipe Design Pressure  

SciTech Connect

This document published results of iterative calculations for maximum tank farm transfer secondary pipe (encasement) pressure upon failure of the primary pipe. The maximum pressure was calculated from a primary pipe guillotine break. Results show encasement pipeline design or testing pressures can be significantly lower than primary pipe pressure criteria.

TEDESCHI, A.R.

2000-10-26

429

Continuous positive airway pressure therapy: New generations  

Microsoft Academic Search

Continuous positive airway pressure (CPAP) is the treatment of choice for obstructive sleep apnoea syndrome (OSAS). However, CPAP is not tolerated by all patients with OSAS and alternative modes of pressure delivery have been developed to overcome pressure intolerance, thereby improving patient comfort and adherence. Auto-adjustable positive airway pressure (APAP) devices may be utilised for the long-term management of OSAS

John F. Garvey; Walter T. McNicholas

2010-01-01

430

Plunger-type fuel pressure regulator  

Microsoft Academic Search

This patent describes improvement in a pressure regulator for use in feeding the output of a relatively high pressure and relatively large liquid volume pump means to a point of use requiring, under some operating conditions, only a relatively small portion of the output volume of the pump means and a substantial reduction of the relatively high pressure, the pressure

G. W. Koechlein; W. O. Wizemann; T. D. Deeds

1991-01-01

431

MEMS pressure sensors – new LGA packagings  

Microsoft Academic Search

Cell phone, medical, white goods and other markets are looking for absolute pressure sensors as well as differential pressure sensors. From a customer point of view these two configurations means to have one or two pressure ports, which could require a piping interface if the measured pressure is not the ambient one. For ambient measurement the MEMS LGA module needs

F. Fontana; L. Baldo; M. Azzopardi; S. Gatt

2009-01-01

432

A mobile robot for pressurizer inspection  

Microsoft Academic Search

The pressurizer is one of the critical components in a nuclear reactor, whose main function is to maintain the primary system pressure within specific boundaries. The pressurizer is a large vessel that is made of carbon or low-alloy steel shell, clad internally with a layer of stainless steel. It works with high temperature, high humidity and high pressure. The crack

Rong-Lei Sun; Xing-Jiang Wan; Heng-Yi Chang

2000-01-01

433

Transition in amorphous selenium under high pressure  

Microsoft Academic Search

The phase transition in amorphous selenium under high pressure was studied. The high pressures were generated using a diamond-indentor technique. From the behavior of electrical resistance of amorphous selenium under high pressure, it was found that amorphous selenium at room temperature starts transforming to a crystalline phase when the pressure is near 97 kbar. The effect of temperature on the

Mool C. Gupta; Arthur L. Ruoff

1978-01-01

434

Ambulatory blood pressure monitoring in hypertensive adolescents.  

PubMed

The purpose of this study was to determine the ability of ambulatory blood pressure monitoring to identify youths with chronic blood pressure elevation. Nineteen adolescent boys were studied, ten had 5-year average systolic or diastolic pressures above the 95th percentile, nine had normal pressure. A Del Mar Avionics Pressurometer III system recorded an average of 121 readings on each subject. The coefficients of variation for pressure were similar for hypertensive and normotensive individuals. During classes, eight of the ten hypertensive youths had elevated pressures in over half of the measurements. Also during these classes eight of ten hypertensive boys had average systolic or diastolic pressure above the 95th percentile, whereas only one of nine normotensive boys had average pressures above this level. We suggest that schooltime ambulatory pressures may be most useful in classifying the blood pressure trend in a youth. PMID:2346634

Fixler, D E; Wallace, J M; Thornton, W E; Dimmitt, P

1990-04-01

435

Peer Pressure for Automatic Troubleshooting  

Microsoft Academic Search

Technical support contributes 17% of the total cost of ownership of today's desktop PCs. An important element of technical support is troubleshooting misconfigured applications. Misconfiguration troubleshooting is particularly challenging, because configuration information is shared and altered by multiple applications. In this paper, we present a novel troubleshooting algorithm, PeerPressure, which uses statistics from a set of sample machines to diagnose

Helen J. Wang; John C. Platt; Yu Chen; Ruyun Zhang; Yi-Min Wang

2004-01-01

436

Isentropic Pressure and Mountain Torques  

Microsoft Academic Search

The relation of pressure torques and mountain torques is investigated on the basis of observations for the polar caps, two midlatitude and two subtropical belts, and a tropical belt by evaluating the lagged covariances of these torques for various isentropic surfaces. It is only in the polar domains and the northern midlatitude belts that the transfer of angular momentum to

Joseph Egger; Klaus-Peter Hoinka

2009-01-01

437

Propellant combustion at low pressures  

Microsoft Academic Search

The combustion characteristics of a family of composite propellants have been investigated at low (i.e., subatmospheric) pressures and three different temperatures. Although a de Vieille-type burning rate law appeared to be applicable, the burning rate exponent and coefficient vary strongly with the initial temperatures. Indications are that this is primarily due to the presence of nitroguanidine and oxalate. Combustion efficiency

H. F. R. Schoyer; P. A. O. G. Korting

1986-01-01

438

Pressures on Youth in Sports  

ERIC Educational Resources Information Center

|The pressures on young athletes today, many of them brought on or exacerbated by parents, drive young athletes to attain perfection and win by any means necessary. For the young athlete, the challenges of learning how to balance schoolwork, social life, family time, and sports, not to mention other interests they might have, are far more intense…

Ungerleider, Steven

2003-01-01

439

Cavitation pressure in liquid helium  

Microsoft Academic Search

Recent experiments have suggested that, at low enough temperature, the homogeneous nucleation of bubbles occurs in liquid helium near the calculated spinodal limit. This was done in pure superfluid helium 4 and in pure normal liquid helium 3. However, in such experiments, where the negative pressure is produced by focusing an acoustic wave in the bulk liquid, the local amplitude

Frederic Caupin; Sebastien Balibar

2001-01-01

440

LLL dynamic high pressure experiments  

Microsoft Academic Search

The Lawrence Livermore Laboratory has several experimental facilities to measure material properties at dynamic high pressures. These include an isobaric expansion experiment, a two-stage light-gas gun, and a high-power laser facility (Janus). Each of these are briefly described.

Nellis

1979-01-01

441

Surface Pressure Altitude Prediction Model.  

National Technical Information Service (NTIS)

A surface pressure altitude (SPA) prediction model has been developed that is totally empirical and based on SPA data from 556 meteorological observation stations in the free world. This model is simple and can be executed very quickly on a microcomputer....

E. P. Avara

1992-01-01

442

Optical Trapping at Gigapascal Pressures  

NASA Astrophysics Data System (ADS)

Diamond anvil cells allow the behavior of materials to be studied at pressures up to hundreds of gigapascals in a small and convenient instrument. However, physical access to the sample is impossible once it is pressurized. We show that optical tweezers can be used to hold and manipulate particles in such a cell, confining micron-sized transparent beads in the focus of a laser beam. Here, we use a modified optical tweezers geometry, allowing us to trap through an objective lens with a higher working distance, overcoming the constraints imposed by the limited angular acceptance of the anvil cell. We demonstrate the effectiveness of the technique by measuring water’s viscosity at pressures of up to 1.3 GPa. In contrast to previous viscosity measurements in anvil cells, our technique measures absolute viscosity and does not require scaling to the accepted value at atmospheric pressure. This method could also measure the frequency dependence of viscosity as well as being sensitive to anisotropy in the medium’s viscosity.

Bowman, Richard W.; Gibson, Graham M.; Padgett, Miles J.; Saglimbeni, Filippo; Di Leonardo, Roberto

2013-03-01

443

High Blood Pressure in Children  

MedlinePLUS

... adults unless they begin treatment. A common complication associated with high blood pressure in children is sleep apnea, a condition in which your child may snore or have abnormal breathing when he or she sleeps. Pay attention to breathing problems your child may have while sleeping. Children who ...

444

The Vapor Pressure of Barium.  

National Technical Information Service (NTIS)

The vapor pressure and the heat of vaporization of barium were measured using the Knudsen target technique. A recording microbalance was used to measure both the effusion rate and the recoil force exerted by the beam onto the target. The measured vapor pr...

P. D. Zavitsanos

1968-01-01

445

Low CSF Volume (Pressure) Headache  

Microsoft Academic Search

The syndrome of persistent low cerebrospinal fluid (CSF) volume (pressure) headache is an important diagnosis for neurologists and others not to miss, because it is a treatable cause of disabling headache. It forms part of the more general diagnostic rubric of New Daily Persistent Headache (NDPH), the key feature of which is a new headache that develops over one or

Peter J. Goadsby; Christopher Boes; Cathie L. M. Sudlow

2002-01-01

446

Thermal Expansion at High Pressures  

Microsoft Academic Search

Estimates of the coefficient of thermal expansion, at pressures up to several megabars, are needed for various geophysical calculations. As experimental determinations are scanty and limited to a few tens of kilobars, we must depend on largely untested deductions from solid-state theory and equations of state. The recent treatment by Anderson [1967], a discussion by Gilvarry [1957], and questions from

Francis Birch

1968-01-01

447

High Blood Pressure During Pregnancy  

MedlinePLUS

... in which there is high blood pressure, and protein is present in the urine. If you have further questions, contact your obstetrician–gynecologist. FAQ034: Designed as an aid to patients, this document sets forth current information and opinions related to women’s ...

448

High Pressure Hydrazine Gas Generator.  

National Technical Information Service (NTIS)

A high pressure hydrazine gas generator has a decomposition chamber which contains therein an initiator of I2O5 crystals and a plurality of heat retaining balls. The liquid hydrazine, which is initially introduced into the decomposition chamber, ignites u...

J. A. Speeds

1977-01-01

449

Protein compressibility, dynamics, and pressure.  

PubMed Central

The relationship between the elastic and dynamic properties of native globular proteins is considered on the basis of a wide set of reported experimental data. The formation of a small cavity, capable of accommodating water, in the protein interior is associated with the elastic deformation, whose contribution to the free energy considerably exceeds the heat motion energy. Mechanically, the protein molecule is a highly nonlinear system. This means that its compressibility sharply decreases upon compression. The mechanical nonlinearity results in the following consequences related to the intramolecular dynamics of proteins: 1) The sign of the electrostriction effect in the protein matrix is opposite that observed in liquids-this is an additional indication that protein behaves like a solid particle. 2) The diffusion of an ion from the solvent to the interior of a protein should depend on pressure nonmonotonically: at low pressure diffusion is suppressed, while at high pressure it is enhanced. Such behavior is expected to display itself in any dynamic process depending on ion diffusion. Qualitative and quantitative expectations ensuing from the mechanical properties are concordant with the available experimental data on hydrogen exchange in native proteins at ambient and high pressure.

Kharakoz, D P

2000-01-01

450

Quantum fluctuations of radiation pressure  

SciTech Connect

Quantum fluctuations of electromagnetic radiation pressure are discussed. We use an approach based on the quantum stress tensor to calculate the fluctuations in velocity and position of a mirror subjected to electromagnetic radiation. Our approach reveals that radiation pressure fluctuations in the case of a coherent state are due to a cross term between vacuum and state dependent terms in a stress tensor operator product. Thus observation of these fluctuations would entail experimental confirmation of this cross term. We first analyze the pressure fluctuations on a single, perfectly reflecting mirror, and then study the case of an interferometer. This involves a study of the effects of multiple bounces in one arm, as well as the correlations of the pressure fluctuations between arms of the interferometer. In all cases, our results are consistent with those previously obtained by Caves using different methods. We argue that the agreement between the different methods supports the reality of the cross term and justifies the methods used in its evaluation.

Wu, Chun-Hsien; Ford, L. H.

2001-08-15

451

Advances in blood pressure genomics.  

PubMed

The elucidation of genes implicated in Mendelian forms of hypertension demonstrates rare variants with substantial effects are responsible, and often these genes lie within pathways managing sodium homeostasis. More recently with advances in affordable high-throughput genotyping strategies, multiple common genetic variants with modest effects on blood pressure (<1 mmHg systolic) have been discovered in the population. In aggregate, these common variants explain <3% of the variance of blood pressure. Although these findings may offer new mechanistic insights into the biology of blood pressure, a key question is can these findings translate into patient benefit? It is timely to reflect on recent advances in genomics, and the use of new resources, such as the 1000 Genomes Project and the Encyclopedia of DNA Elements, to annotate likely causal variants, and their relevance to cardiovascular disease. In this review, we discuss the advances in relation to our knowledge of the genetic architecture of blood pressure, and whether gene discoveries might influence cardiovascular risk assessment, help to stratify patient response to medicine, or identify new biological pathways for novel therapeutic targets. PMID:23661711

Munroe, Patricia B; Barnes, Michael R; Caulfield, Mark J

2013-05-10

452

Vegetarian Diet and Blood Pressure  

Microsoft Academic Search

There is now convincing evidence from epidemiological studies and randomized controlled trials that adoption of an ovo-lacto vegetarian diet leads to blood pressure reduction in both normotensive and hypertensive subjects. This effect appears to be independent of both dietary sodium and weight loss but additive to effects of weight reduction. Long-term adherence to a vegetarian diet is associated with less

L. J. Beilin; B. K. Armstrong; B. M. Margetts; I. L. Rouse; R. Vandongen

1987-01-01

453

Optical trapping at gigapascal pressures.  

PubMed

Diamond anvil cells allow the behavior of materials to be studied at pressures up to hundreds of gigapascals in a small and convenient instrument. However, physical access to the sample is impossible once it is pressurized. We show that optical tweezers can be used to hold and manipulate particles in such a cell, confining micron-sized transparent beads in the focus of a laser beam. Here, we use a modified optical tweezers geometry, allowing us to trap through an objective lens with a higher working distance, overcoming the constraints imposed by the limited angular acceptance of the anvil cell. We demonstrate the effectiveness of the technique by measuring water's viscosity at pressures of up to 1.3 GPa. In contrast to previous viscosity measurements in anvil cells, our technique measures absolute viscosity and does not require scaling to the accepted value at atmospheric pressure. This method could also measure the frequency dependence of viscosity as well as being sensitive to anisotropy in the medium's viscosity. PMID:23496726

Bowman, Richard W; Gibson, Graham M; Padgett, Miles J; Saglimbeni, Filippo; Di Leonardo, Roberto

2013-02-28

454

High pressure tubular swivel joint  

Microsoft Academic Search

A swivel joint and connection for abutting high pressure hydraulic manifolding are described. The joint consists of 2 flanged nonrotating swivel bodies, with one of the nonrotating swivel bodies having a rotating swivel body journaled in it. A flanged tubular sleeve is secured between the adjacent end faces of the 2 nonrotating swivel bodies, with the opposite ends of the

W. D. Kendrick; B. J. Frazier

1976-01-01

455

Water Pressure. Water in Africa.  

ERIC Educational Resources Information Center

The Water in Africa Project was realized over a 2-year period by a team of Peace Corps volunteers. As part of an expanded, detailed design, resources were collected from over 90 volunteers serving in African countries, photos and stories were prepared, and standards-based learning units were created for K-12 students. This unit, "Water Pressure,"…

Garrett, Carly Sporer

456

Pressure coring provides innovative approach  

SciTech Connect

Pressure coring offers the industry a new perspective in tertiary recovery project evaluation. Engineering of experimental tests requires innovative thinking and results in a higher degree of data reliability. Residual water saturation after waterflood should be the primary objective of the experimental project. The project manager should not consider the pressure core as a sole source of data. By combing drilling, corring, logging and production data, the engineer can determine the best possible values for tertiary recovery project evaluation. During late 1979, Gruy Federal Inc., under contract to DOE, participated with the operator in pressure coring operations in Texas Pacific Bru No. 310, Bennett Ranch unit, Wasson field, W. Texas. Engineers planned the well as part of a program to continue development of the waterflood unit on 20-acre spacing. In all, workers cut 26 cores over a 210-ft interval of the San Andres dolomite. The cored interval extended 50 feet below the estimated original oil-water contact, allowing evaluation for CO/sub 2/ floodable oil saturation in the transition zone. Analysis of the pressure coring data provided valuable information that could not be obtained from conventional cores or logs. 14 references.

Swift, T.E.; Kumar, R.; Goodrich, J.; McCoy, R.L.

1981-08-01

457

The Power of Peer Pressure  

ERIC Educational Resources Information Center

|In a religion class of 26 bright creative sixth graders, one student demonstrates the power of peer pressure. Part of the morning ritual is to say prayer petitions. Students seems to be calmed by their expressions of care for their families, friends, pets, their military troops, victims of natural disasters, the homeless, etc. However, one…

Wingle, Jane

2006-01-01

458

Malthusian pressures, genocide, and ecocide.  

PubMed

Historical models postulate that genocide cannot occur without the ideology and decisions of its authoritarian perpetrators and the indifference of bystanders. These models do not address genocidal risks from ecocide. Study objectives were to assess 1) the role of Malthusian pressures in recent genocides, 2) the role of ecocide and ecologic abuse in creating these pressures, and 3) strategies for prevention and deterrence. Analysis of reports, demographic studies, and time trends in recent genocides and recent ecocidal events from ecologic abuse suggests that Malthusian pressures and zero-sum rivalries over water, arable land, or natural resources by themselves do not lead to genocide. Such pressures may have exacerbated the political and socioeconomic predictors in Rwanda and Darfur, but not in former Yugoslavia. However, collapse of socioeconomic and governmental infrastructures following genocide can leave behind massive sustained damage to carrying capacity and sustainability. Surviving victims, if they return to their environments, will remain at risk for persecution. Ecocide--the large-scale destruction, depletion, or contamination of natural ecosystems--can result in widespread damage to health, survival, fertility, reproduction, and sustenance, and forced flight. International early warning and effective response systems are needed to deter or prevent political decisions to carry out genocide. Such systems must include long-term measures to resolve zero-sum conflicts over environmental resources and to prevent toxic risks to vulnerable populations and destruction of habitat by deliberate or wanton ecologic abuse, which itself should be redefined as a crime against humanity. PMID:17915548

Richter, Elihu D; Blum, Rony; Berman, Tamar; Stanton, Gregory H

459

Letter: Calcium and blood pressure  

Microsoft Academic Search

While I greatly enjoyed the editorial by Prof. Kaplan (1988;2:269-274) on calcium and blood pressure, I do not agree with his conclusion that until the biochemical markers for responsiveness to calcium supplements are better defined (p. 273, last para.), calcium should not be used in the treatment of hypertension. One of the striking problems is that most of us are

R. B. Singh

1990-01-01

460

Atmospheric-pressure plasma jet  

DOEpatents

Atmospheric-pressure plasma jet. A .gamma.-mode, resonant-cavity plasma discharge that can be operated at atmospheric pressure and near room temperature using 13.56 MHz rf power is described. Unlike plasma torches, the discharge produces a gas-phase effluent no hotter than 250.degree. C. at an applied power of about 300 W, and shows distinct non-thermal characteristics. In the simplest design, two concentric cylindrical electrodes are employed to generate a plasma in the annular region therebetween. A "jet" of long-lived metastable and reactive species that are capable of rapidly cleaning or etching metals and other materials is generated which extends up to 8 in. beyond the open end of the electrodes. Films and coatings may also be removed by these species. Arcing is prevented in the apparatus by using gas mixtures containing He, which limits ionization, by using high flow velocities, and by properly shaping the rf-powered electrode. Because of the atmospheric pressure operation, no ions survive for a sufficiently long distance beyond the active plasma discharge to bombard a workpiece, unlike low-pressure plasma sources and conventional plasma processing methods.

Selwyn, Gary S. (Los Alamos, NM)

1999-01-01

461

Response of Periodically Stiffened Shells to a Moving Projectile Propelled by an Internal Pressure Wave  

Microsoft Academic Search

The vibrations of cylindrical shells induced by a moving projectile propelled by an internal pressure wave are controlled by placing stiffening rings periodically along the length of the shell. An expanding pressure step causes the axisymmetric radial displacement of the shell to be several times higher than that produced by the static application of the same pressure. The displacement depends

M. Ruzzene; A. Baz

2006-01-01

462

Apparatus for the measurement of light reflection of cholesteric mesophases at high pressures  

Microsoft Academic Search

An apparatus for determining the wavelength of maximum reflection of light lambda R of cholesteric mesophases at high static pressures is described. The arrangement of the whole high pressure equipment is briefly outlined. The pressure chamber allows optical measurements up to 5000 bar and can be thermostated by oil on the outside. Details of the sample cell are illustrated. The

P. Pollmann

1974-01-01

463

An Investigation of the Surface Pressure Fields beneath Simulated Tornado Cyclones  

Microsoft Academic Search

The wall static pressure fields beneath tornado-like vortices have been investigated using a large vortex generator especially designed to model tornado cyclone airflow. Presented in nondimensional form, the data include both a series of radial profiles across the mean pressure field under a variety of flow conditions, and a detailed investigation of the magnitude of the central pressure as a

J. T. Snow; C. R. Church; B. J. Barnhart

1980-01-01

464

New high-pressure transformation in [alpha]-quartz  

SciTech Connect

Recent experimental and theoretical studies report that quenched pressure-amorphized [alpha]-quartz is elastically anisotropic and displays a reversal of anisotropy with respect to the original crystallographic orientation. We demonstrate that samples recovered from static compression experiments of [alpha]-quartz exhibit an unusual pressure-induced microstructure, which arises from a new phase transformation in [alpha]-quartz at 21 GPa. Upon decompression, the high-pressure phase reverts to a quartzlike structure in a twinned state, accounting for the previously reported elastic behavior.

Kingma, K.J.; Hemley, R.J.; Mao, H.; Veblen, D.R. (Geophysical Laboratory and Center for High Pressure Research, Carnegie Institution of Washington, 5251 Broad Branch Road NW, Washington, D.C. 20015 (United States) Department of Earth and Planetary Sciences, The Johns Hopkins University, Baltimore, Maryland 21218 (United States))

1993-06-21

465

The impact of pressure, temperature and treatment time on starches: pressure-induced starch gelatinisation as pressure time temperature indicator for high hydrostatic pressure processing  

Microsoft Academic Search

The applicability of pressure-induced starch gelatinisation as a pressure time temperature indicator (PTTI) was investigated by examining the impact of pressure, temperature and treatment time on starches of A-type, B-type and C-type crystallinity. Pressure-induced starch gelatinisation was highly sensitive to changes of temperature, pressure and treatment time. At constant temperature and treatment time, the degree of gelatinisation increased with increasing

B. A. Bauer; D. Knorr

2005-01-01

466

Combustion Oscillation Analysis of Premixed Flames at Elevated Pressures  

NASA Astrophysics Data System (ADS)

A new analytical time lag flame model based on Bloxidge’s flame model was introduced, which calculates the combustion oscillation of premixed flame to take into account the distribution of heat release rate and flame speed that was calculated by analytical formulas dependent on pressure, temperature, fuel-to-air ratio and velocity. The transfer matrix technique using the new flame model was applied to the calculation of acoustic resonance characteristics. To verify the model, combustion oscillation experiments were performed for methane-air premixed flames stabilized by a swirl burner at elevated pressures in a range of 0.6-0.9MPa. The fluctuating pressure had a maximum peak at a specific value of f?f, where f is the resonance frequency and ?f is the passing time of premixed gas through the flame zone. The analytical model could simulate the dependency of the fluctuating pressure local peak on the fuel-to-air ratio and the static pressure.

Ohtsuka, Masaya; Yoshida, Shohei; Inage, Shin'Ichi; Kobayashi, Nariyoshi

467

Experimental analysis and computer modelling of turbocharger system pressure drop  

SciTech Connect

This paper describes development of a computer model and experimental test equipment for analysis of pressure and temperature distribution in charge air systems including charge air cooler. Turbocharging and charge air cooling are being used on heavy truck applications at an ever increasing rate. System pressure loss is an important design criteria for charge air cooling. Each system component is analyzed separately in the computer model using basic principles of thermodynamics and fluid mechanics to determine temperature and pressure of the air flowing through the system. The full size system with actual hardware from the engine and ducting system is assembled on the test stand to model in-vehicle geometries. Temperature, static, and total pressure were measured at various points to determine the contribution of each geometric feature to pressure changes in the system. Excellent correlation was obtained between computer, test stand and actual vehicle test results.

Beldam, R.P.; Cheong, A.S.; Helberg, K.H.

1987-01-01

468

Research on Rail Pressure Signal Processing Method of High Pressure Common Rail System  

Microsoft Academic Search

The rail pressure signal of electronic control high pressure common rail fuel injection system for diesel engines is used to the closed loop control for rail pressure and the determination of the energizing time for fuel injection. Traditionally rail pressure signal processing method uses 10 ms filter to get the average rail pressure for control the system. With the rail

Qiu Tao; Wang Changyuan; Fan Zhiqiang; Qi Zhiquan; Yin Wenhui

2010-01-01

469

An investigation of the heat transfer and static pressure on the over-tip casing wall of an axial turbine operating at engine representative flow conditions. (I). Time-mean results  

Microsoft Academic Search

The over-tip casing of the high-pressure turbine in a modern gas turbine engine is subjected to strong convective heat transfer that can lead to thermally induced failure (burnout) of this component. However, the complicated flow physics in this region is dominated by the close proximity of the moving turbine blades, which gives rise to significant temporal variations at the blade-passing

S. J. Thorpe; S. Yoshino; R. W. Ainsworth; N. W. Harvey

2004-01-01

470

Sensitivity of compliance-based continuous non-invasive blood pressure monitoring to changes in viscoelastic parameters  

Microsoft Academic Search

The apparent arterial compliance observed from non- invasive measurements of arterial blood pressure and cross- sectional area does not directly correspond to the static compliance curve or dynamic pressure-area loop. The accuracy of continuous, non-invasive blood pressure estimates based on calibrated arterial compliance models to convert area to pressure is affected by both changes in the viscoelastic properties of the

A. M. Dentinger; C. Jia

2011-01-01

471

Pressure-Induced Transformations in Silica  

NASA Astrophysics Data System (ADS)

Polymorphic phase transitions in the silica minerals alpha-quartz and stishovite have been investigated using diamond-anvil cell techniques at room temperature. Structural and vibrational properties of these materials were monitored as a function of pressure using in situ Raman scattering, synchrotron x-ray diffraction, and optical microscopy. Pressure-quenched samples were characterized at ambient conditions using Raman spectroscopy, electron diffraction, transmission electron microscopy, backscattered and secondary electron imaging, and optical microscopy. Solid-state amorphization of alpha -quartz has been found to begin with formation of crystallographically controlled planar defects, followed by growth of amorphous silica at these defect sites. Characteristic microstructures (planar defects and amorphous lamellae) are found in quartz upon quasihydrostatic and nonhydrostatic compression and from comminution, suggesting that there is a common mechanism for solid-state amorphization of silicates in static and shock compression experiments, meteorite impact, and deformation by tectonic processes. A new crystalline-crystalline transformation has been discovered in alpha-quartz at 21 GPa, documented by abrupt changes in the synchrotron x-ray diffraction pattern and the Raman spectrum. Upon decompression, the high-pressure phase reverts to a quartz -like structure in an unusual twinned state. The Raman spectrum of samples recovered from hydrostatic compression closely resembles spectra of both dynamically shocked quartz and quartz that has experienced extensive grinding; each shows significant deviations from the spectrum of pristine quartz. The transformation from rutile-structured silica (stishovite) to the CaCl_2-structured form has been documented by high-pressure Raman scattering at 51 GPa. At this pressure, the pressure dependence of the soft B_{1rm g} vibrational mode changes sign, and the stishovite E _{rm g} mode splits, as predicted for the transformation to the CaCl_2 structure. The spectral changes are continuous and reversible with no hysteresis, suggesting that the transformation is second-order. Finally, the Raman spectrum of the recently documented new silica phase "moganite" has been measured at ambient conditions. Comparison with Raman spectra of other tetrahedrally coordinated minerals confirms that "moganite" is a structurally distinct polymorph of silica.

Kingma, Kathleen Jane

472

High pressure synthesis gas fermentation  

SciTech Connect

The purpose of this research project is to build and test a pressure fermentation system for the production of ethanol from synthesis gas. The fermenters, pumps, controls, and analytical system will be procured or fabricated and assembled in our laboratory. This system will then be used to determine the effects of high pressure on growth and ethanol production by clostridium ljungdahlii. The limits of cell concentration and mass transport relationships will be found in continuous stirred tank reactor and immobilized cell reactors. The minimum retention times and reactor volumes will be found for ethanol production in these reactors. Retention times of a few seconds are expected to result from these experiments. 2 figs., 2 tabs.

Not Available

1991-01-01

473

Ambient pressure fuel cell system  

DOEpatents

An ambient pressure fuel cell system is provided with a fuel cell stack formed from a plurality of fuel cells having membrane/electrode assemblies (MEAs) that are hydrated with liquid water and bipolar plates with anode and cathode sides for distributing hydrogen fuel gas and water to a first side of each one of the MEAs and air with reactant oxygen gas to a second side of each one of the MEAs. A pump supplies liquid water to the fuel cells. A recirculating system may be used to return unused hydrogen fuel gas to the stack. A near-ambient pressure blower blows air through the fuel cell stack in excess of reaction stoichiometric amounts to react with the hydrogen fuel gas.

Wilson, Mahlon S. (Los Alamos, NM)

2000-01-01

474

Recent developments in pressure coring  

SciTech Connect

The current rapid growth in the number of enhanced oil and gas recovery projects has created a strong demand for reservoir data such as true residual oil saturations. The companies providing pressure coring services have moved to fill this need. Two recent developments have emerged with the potential of significantly improving the present performance of pressure coring. Coring bits utilizing synthetic diamond cutters have demonstrated coring rates of one-foot per minute while improving core recovery. It is also apparent that cores of a near-unconsolidated nature are more easily recovered. In addition, a special low invasion fluid that is placed in the core retriever has demonstrated reduced core washing by the drilling mud and a decrease in the complexity of preparing cores for analysis. This paper describes the design, laboratory, and field testing efforts that led to these coring improvements. Also, experience in utilizing these developments while recovering over 100 cores is discussed.

McFall, A. L.

1980-01-01

475

Low cerebrospinal fluid pressure headache  

Microsoft Academic Search

Opinion statement  \\u000a \\u000a \\u000a \\u000a \\u000a – \\u000a \\u000a Alterations in cerebrospinal fluid (CSF) pressure lead to neurologic symptoms, the most common clinical manifestation of which\\u000a is headache. Typically, the headache is orthostatic and related to traction on pain-sensitive intracranial and meningeal structures,\\u000a distention on periventricular pain-sensitive areas, and direct pressure on pain conveying cranial nerves.\\u000a \\u000a \\u000a \\u000a \\u000a – \\u000a \\u000a Low CSF headache is a distinct and familiar syndrome

Christine M. Lay

2002-01-01

476

Glassy dynamics under superhigh pressure.  

PubMed

Nearly all glass-forming liquids feature, along with the structural alpha-relaxation process, a faster secondary process (beta relaxation), whose nature belongs to the great mysteries of glass physics. However, for some of these liquids, no well-pronounced secondary relaxation is observed. A prominent example is the archetypical glass-forming liquid glycerol. In the present work, by performing dielectric spectroscopy under superhigh pressures up to 6 GPa, we show that in glycerol a significant secondary relaxation peak appears in the dielectric loss at P>3 GPa. We identify this beta relaxation to be of Johari-Goldstein type and discuss its relation to the excess wing. We provide evidence for a smooth but significant increase in glass-transition temperature and fragility on increasing pressure. PMID:20481727

Pronin, A A; Kondrin, M V; Lyapin, A G; Brazhkin, V V; Volkov, A A; Lunkenheimer, P; Loidl, A

2010-04-14

477

Glassy dynamics under superhigh pressure  

NASA Astrophysics Data System (ADS)

Nearly all glass-forming liquids feature, along with the structural ? -relaxation process, a faster secondary process ( ? relaxation), whose nature belongs to the great mysteries of glass physics. However, for some of these liquids, no well-pronounced secondary relaxation is observed. A prominent example is the archetypical glass-forming liquid glycerol. In the present work, by performing dielectric spectroscopy under superhigh pressures up to 6 GPa, we show that in glycerol a significant secondary relaxation peak appears in the dielectric loss at P>3GPa . We identify this ? relaxation to be of Johari-Goldstein type and discuss its relation to the excess wing. We provide evidence for a smooth but significant increase in glass-transition temperature and fragility on increasing pressure.

Pronin, A. A.; Kondrin, M. V.; Lyapin, A. G.; Brazhkin, V. V.; Volkov, A. A.; Lunkenheimer, P.; Loidl, A.

2010-04-01

478

CHRONOBIOLOGY OF HIGH BLOOD PRESSURE  

PubMed Central

BIOCOS, the project aimed at studying BIOlogical systems in their COSmos, has obtained a great deal of expertise in the fields of blood pressure (BP) and heart rate (HR) monitoring and of marker rhythmometry for the purposes of screening, diagnosis, treatment, and prognosis. Prolonging the monitoring reduces the uncertainty in the estimation of circadian parameters; the current recommendation of BIOCOS requires monitoring for at least 7 days. The BIOCOS approach consists of a parametric and a non-parametric analysis of the data, in which the results from the individual subject are being compared with gender- and age-specified reference values in health. Chronobiological designs can offer important new information regarding the optimization of treatment by timing its administration as a function of circadian and other rhythms. New technological developments are needed to close the loop between the monitoring of blood pressure and the administration of antihypertensive drugs.

Cornelissen, G.; Halberg, F.; Bakken, E. E.; Wang, Z.; Tarquini, R.; Perfetto, F.; Laffi, G.; Maggioni, C.; Kumagai, Y.; Homolka, P.; Havelkova, A.; Dusek, J.; Svacinova, H.; Siegelova, J.; Fiser, B.

2008-01-01

479

Self-contained fuel pressure regulator  

SciTech Connect

This patent describes a self-contained fuel pressure regulator assembly adapted for plug-connection directly to an engine manifold and fuel rail assembly. The manifold and fuel rail assembly having a fitting for transferring pressure from the manifold and an adapter for transferring fuel from the fuel rail, the pressure regulator assembly comprising a base having a fuel chamber adapted for plug-connection directly to the adapter to receive fuel from the fuel rail, the base also having a fuel discharge passage and a valve seat in the discharge passage through which fuel flows from the chamber to the discharge passage, a flexible diaphragm closing the chamber, a valve member positioned by the diaphragm to control fuel flow through the valve seat, a cover forming a pressure chamber with the diaphragm, the base further having a pressure passage adapted for plug-connection directly to the fitting, the pressure passage extending to the pressure chamber to transfer the pressure in the manifold to the pressure chamber, and a spring having a bias supplementing the manifold pressure in the pressure chamber acting on the diaphragm and opposing the fuel pressure in the fuel chamber acting on the diaphragm, whereby the diaphragm may flex in response to variations in fuel pressure in the fuel chamber and manifold pressure in the pressure chamber and position the valve member to maintain the pressure in the fuel chamber and thus in the fuel rail balanced with the bias of the spring and the pressure in the pressure chamber and thus in the manifold.

Rock, J.A.; Sherwood, C.H.

1988-07-12

480

Pressurized fluidized bed Combustion technology  

Microsoft Academic Search

The technology of pressurized fluidized bed combustion (PFBC), particularly in its application to a coal-burning combinedcycle (CC) plant, is evaluated in this book. Engineering systems analyses are performed for advanced concept plant components-boiler systems, including combustors, air-handling and air-injection equipment, and heat exchangers; solids handling, injection and ejection systems; hot-gas cleanup equipment; instrumentation and control systems; and turbines-and materials of

W. F. etc. Podolski; R. L. etc. Graves

1983-01-01

481

Modeling of Intracranial Pressure Dynamics  

PubMed Central

Digital computer simulation is utilized to test hypotheses regarding poorly understood mechanisms of intracranial pressure change. The simulation produces graphic output similar to records from polygraph recorders used in patient monitoring and in animal experimentation. The structure of the model is discussed. The mathematic model perfected by the comparison between simulation and experiment will constitute a formulation of medical information applicable to automated clinical monitoring and treatment of intracranial hypertension.

Griffith, Richard L.; Sullivan, Humbert G.; Miller, J. Douglas

1978-01-01

482

High pressure paint gun injuries.  

PubMed Central

Despite their use for the past 20 years the dangers of injuries from high pressure paint guns are not widely known. Two cases treated incorrectly through ignorance in our casualty department resulted in amputation of digits. Paint solvents are far moe damaging than paint of grease injection. All cases should be treated urgently by an experienced surgeon as fairly extensive surgery may be needed. Images FIG 1 FIG 2 FIG 3 FIG 4

Booth, C M

1977-01-01

483

``Swiss cheese'' models with pressure  

NASA Astrophysics Data System (ADS)

Local spherically symmetric inhomogeneities are matched to a spatially flat Robertson-Walker background with pressure. In the cases in which the background evolves to an Einstein-de Sitter dust universe, the interior metrics tend with time either to the vacuum Schwarzschild solution or to the spatially flat Tolman dust metrics. The whole construction may be interpreted as the history of the dust-filled ``Swiss cheese'' models.

Bona, C.; Stela, J.

1987-11-01

484

Variable pressure thermal insulating jacket  

DOEpatents

A device for controlled insulation of a thermal device. The device includes a thermal jacket with a closed volume able to be evacuated to form an insulating jacket around the thermal source. A getter material is in communcation with the closed volume of the thermal jacket. The getter material can absorb and desorb a control gas to control gas pressure in the volume of the thermal jacket to control thermal conductivity in the thermal jacket.

Nelson, Paul A. (Wheaton, IL); Malecha, Richard F. (Naperville, IL); Chilenskas, Albert A. (Chicago, IL)

1994-01-01

485

Familial Aggregation of Blood Pressure  

Microsoft Academic Search

\\u000a In the first half of the last century, evidence for the familial aggregation of (elevated) blood pressure (BP) levels was\\u000a largely anecdotal and based on case reports of clinicians until a number of large family studies in the 1960s showed familial\\u000a resemblance of BP with correlations around 0.20 among first-degree relatives (1,2). Relatively few observations were made in children in

Xiaoling Wang; Harold Snieder

486

Dynamics of Radiation Pressure Acceleration  

SciTech Connect

We describe recent theoretical results on Radiation Pressure Acceleration of ions by ultraintense, circularly polarized laser pulses, giving an insight on the underlying dynamics and suggestions for the development of applications. In thick targets, we show how few-cycle pulses may generate single ion bunches in inhomogeneous density profiles. In thin targets, we present a refinement of the simple model of the accelerating mirror and a comparison of its predictions with simulation results, solving an apparent paradox.

Macchi, A. [CNR/INFM/polyLAB, Pisa (Italy); Dipartimento di Fisica 'Enrico Fermi', Largo Bruno Pontecorvo 3, I-56127 Pisa (Italy); Benedetti