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1

Static Pressure-Assisted Seal For Helium  

NASA Technical Reports Server (NTRS)

Two-piece, all-metal, pressure-assisted static flange seal holds in pressurized helium satisfactorily at temperature of negative 80 degree F (negative 62 degree C). Installed between two flanges, then bolted together. New version includes one pressure-assisted metal sealing element held in place by metal plate and flanges. Certified for use in flight on helium joints of Space Shuttle main engine. Likely terrestrial applications include laboratory and industrial gas-distribution systems.

Stuck, Donald E.; Okabayashi, Takateru

1990-01-01

2

14 CFR 23.1325 - Static pressure system.  

Code of Federal Regulations, 2010 CFR

...2010-01-01 2010-01-01 false Static pressure system. 23.1325 Section 23.1325...Installation § 23.1325 Static pressure system. (a) Each instrument provided with static pressure case connections must be so...

2010-01-01

3

14 CFR 25.1325 - Static pressure systems.  

Code of Federal Regulations, 2010 CFR

...2010-01-01 2010-01-01 false Static pressure systems. 25.1325 Section 25...Installation § 25.1325 Static pressure systems. (a) Each instrument...located in such manner that the static pressure system performance is least...

2010-01-01

4

14 CFR 25.1325 - Static pressure systems.  

Code of Federal Regulations, 2013 CFR

...2013-01-01 2013-01-01 false Static pressure systems. 25.1325 Section 25...Installation § 25.1325 Static pressure systems. (a) Each instrument...located in such manner that the static pressure system performance is least...

2013-01-01

5

14 CFR 25.1325 - Static pressure systems.  

Code of Federal Regulations, 2012 CFR

...2012-01-01 2012-01-01 false Static pressure systems. 25.1325 Section 25...Installation § 25.1325 Static pressure systems. (a) Each instrument...located in such manner that the static pressure system performance is least...

2012-01-01

6

14 CFR 23.1325 - Static pressure system.  

Code of Federal Regulations, 2013 CFR

...2013-01-01 2013-01-01 false Static pressure system. 23.1325 Section 23.1325...Installation § 23.1325 Static pressure system. (a) Each instrument provided with static pressure case connections must be so...

2013-01-01

7

14 CFR 25.1325 - Static pressure systems.  

Code of Federal Regulations, 2014 CFR

...2014-01-01 2014-01-01 false Static pressure systems. 25.1325 Section 25...Installation § 25.1325 Static pressure systems. (a) Each instrument...located in such manner that the static pressure system performance is least...

2014-01-01

8

14 CFR 23.1325 - Static pressure system.  

Code of Federal Regulations, 2014 CFR

...2014-01-01 2014-01-01 false Static pressure system. 23.1325 Section 23.1325...Installation § 23.1325 Static pressure system. (a) Each instrument provided with static pressure case connections must be so...

2014-01-01

9

14 CFR 23.1325 - Static pressure system.  

Code of Federal Regulations, 2012 CFR

...2012-01-01 2012-01-01 false Static pressure system. 23.1325 Section 23.1325...Installation § 23.1325 Static pressure system. (a) Each instrument provided with static pressure case connections must be so...

2012-01-01

10

14 CFR 23.1325 - Static pressure system.  

Code of Federal Regulations, 2011 CFR

...2011-01-01 2011-01-01 false Static pressure system. 23.1325 Section 23.1325...Installation § 23.1325 Static pressure system. (a) Each instrument provided with static pressure case connections must be so...

2011-01-01

11

14 CFR 25.1325 - Static pressure systems.  

Code of Federal Regulations, 2011 CFR

...2011-01-01 2011-01-01 false Static pressure systems. 25.1325 Section 25...Installation § 25.1325 Static pressure systems. (a) Each instrument...located in such manner that the static pressure system performance is least...

2011-01-01

12

Martian Atmospheric Pressure Static Charge Elimination Tool  

NASA Technical Reports Server (NTRS)

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

Johansen, Michael R.

2014-01-01

13

14 CFR 29.1325 - Static pressure and pressure altimeter systems.  

Code of Federal Regulations, 2014 CFR

...port must be designed and located in such manner that the correlation between air pressure in the static pressure system and true ambient atmospheric static pressure is not altered when the rotorcraft encounters icing conditions. An...

2014-01-01

14

14 CFR 29.1325 - Static pressure and pressure altimeter systems.  

Code of Federal Regulations, 2013 CFR

...port must be designed and located in such manner that the correlation between air pressure in the static pressure system and true ambient atmospheric static pressure is not altered when the rotorcraft encounters icing conditions. An...

2013-01-01

15

14 CFR 29.1325 - Static pressure and pressure altimeter systems.  

Code of Federal Regulations, 2011 CFR

...port must be designed and located in such manner that the correlation between air pressure in the static pressure system and true ambient atmospheric static pressure is not altered when the rotorcraft encounters icing conditions. An...

2011-01-01

16

14 CFR 29.1325 - Static pressure and pressure altimeter systems.  

Code of Federal Regulations, 2012 CFR

...port must be designed and located in such manner that the correlation between air pressure in the static pressure system and true ambient atmospheric static pressure is not altered when the rotorcraft encounters icing conditions. An...

2012-01-01

17

14 CFR 29.1325 - Static pressure and pressure altimeter systems.  

Code of Federal Regulations, 2010 CFR

...port must be designed and located in such manner that the correlation between air pressure in the static pressure system and true ambient atmospheric static pressure is not altered when the rotorcraft encounters icing conditions. An...

2010-01-01

18

30 CFR 18.67 - Static-pressure tests.  

Code of Federal Regulations, 2010 CFR

... § 18.67 Static-pressure tests. Static-pressure tests shall be conducted by the applicant...design when MSHA determines that visual inspection will not reveal defects...in single-seam welds. Such test procedure shall be...

2010-07-01

19

30 CFR 7.307 - Static pressure test.  

Code of Federal Regulations, 2014 CFR

...2014-07-01 2014-07-01 false Static pressure test. 7.307 Section 7.307 ...Motor Assemblies § 7.307 Static pressure test. (a) Test procedure. ...pressurized to a minimum of 150 psig and the pressure maintained for a minimum of 10...

2014-07-01

20

14 CFR 27.1325 - Static pressure systems.  

Code of Federal Regulations, 2013 CFR

...2013-01-01 2013-01-01 false Static pressure systems. 27.1325 Section 27...Installation § 27.1325 Static pressure systems. (a) Each instrument...affect its accuracy. (b) Each static pressure port must be designed and located...

2013-01-01

21

14 CFR 27.1325 - Static pressure systems.  

Code of Federal Regulations, 2014 CFR

...2014-01-01 2014-01-01 false Static pressure systems. 27.1325 Section 27...Installation § 27.1325 Static pressure systems. (a) Each instrument...affect its accuracy. (b) Each static pressure port must be designed and located...

2014-01-01

22

14 CFR 27.1325 - Static pressure systems.  

Code of Federal Regulations, 2010 CFR

...2010-01-01 2010-01-01 false Static pressure systems. 27.1325 Section 27...Installation § 27.1325 Static pressure systems. (a) Each instrument...affect its accuracy. (b) Each static pressure port must be designed and located...

2010-01-01

23

14 CFR 27.1325 - Static pressure systems.  

Code of Federal Regulations, 2012 CFR

...2012-01-01 2012-01-01 false Static pressure systems. 27.1325 Section 27...Installation § 27.1325 Static pressure systems. (a) Each instrument...affect its accuracy. (b) Each static pressure port must be designed and located...

2012-01-01

24

14 CFR 27.1325 - Static pressure systems.  

Code of Federal Regulations, 2011 CFR

...2011-01-01 2011-01-01 false Static pressure systems. 27.1325 Section 27...Installation § 27.1325 Static pressure systems. (a) Each instrument...affect its accuracy. (b) Each static pressure port must be designed and located...

2011-01-01

25

Static pressure test automatic control system  

NASA Astrophysics Data System (ADS)

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

Chen, Jian

1988-12-01

26

30 CFR 7.104 - Internal static pressure test.  

Code of Federal Regulations, 2014 CFR

...2014-07-01 false Internal static pressure test. 7.104 Section 7.104 ...Required § 7.104 Internal static pressure test. (a) Test procedures. ...exhaust system to four times the maximum pressure observed in each segment during the...

2014-07-01

27

Measurement of the True Dynamic and Static Pressures in Flight  

NASA Technical Reports Server (NTRS)

In this report, two reliable methods are presented, with the aid of which the undisturbed flight dynamic pressure and the true static pressure may be determined without error. These problems were solved chiefly through practical flight tests.

Kiel, Georg

1939-01-01

28

30 CFR 7.104 - Internal static pressure test.  

Code of Federal Regulations, 2010 CFR

...Resources 1 2010-07-01 2010-07-01 false Internal static pressure test. 7.104 Section 7.104 Mineral Resources...Permissible Electric Equipment is Required § 7.104 Internal static pressure test. (a) Test procedures. (1)...

2010-07-01

29

30 CFR 7.307 - Static pressure test.  

Code of Federal Regulations, 2010 CFR

...Mineral Resources 1 2010-07-01 2010-07-01 false Static pressure test. 7.307 Section 7.307 Mineral Resources...APPLICANT OR THIRD PARTY Electric Motor Assemblies § 7.307 Static pressure test. (a) Test procedure. (1) The...

2010-07-01

30

Velocity-pressure correlation measurement based on planar PIV and miniature static pressure probes  

NASA Astrophysics Data System (ADS)

This study aimed to measure pressure-related turbulence statistics such as the velocity-pressure or the pressure-strain correlations. To do so, the pressure field evaluation based on the velocity data measured by particle image velocimetry (PIV) was combined with direct single-point-measurement by miniature static pressure probes (SP-probe). The instantaneous pressure field was derived from the measurement results by PIV, and the pressure fluctuations associated with the large-scale vortex motion were extracted using the instantaneous pressure directly measured by the SP-probe as a reference signal. The measurement was taken in a turbulent near wake of a circular cylinder. After the validity of the instantaneous pressure evaluated from the PIV data was addressed, the velocity-pressure correlation and the pressure-strain correlation were investigated.

Kawata, Takuya; Obi, Shinnosuke

2014-07-01

31

Pressure  

NSDL National Science Digital Library

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

Wolfgang Christian

32

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

33

30 CFR 18.67 - Static-pressure tests.  

Code of Federal Regulations, 2012 CFR

...Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR TESTING, EVALUATION, AND APPROVAL OF MINING PRODUCTS ELECTRIC MOTOR-DRIVEN MINE EQUIPMENT AND ACCESSORIES Inspections and Tests § 18.67 Static-pressure...

2012-07-01

34

30 CFR 250.1153 - When must I conduct a static bottomhole pressure survey?  

Code of Federal Regulations, 2011 CFR

...When must I conduct a static bottomhole pressure survey? 250.1153 Section 250...When must I conduct a static bottomhole pressure survey? (a) You must conduct a static bottomhole pressure survey under the following...

2011-07-01

35

30 CFR 250.1153 - When must I conduct a static bottomhole pressure survey?  

Code of Federal Regulations, 2010 CFR

...When must I conduct a static bottomhole pressure survey? 250.1153 Section 250...When must I conduct a static bottomhole pressure survey? (a) You must conduct a static bottomhole pressure survey under the following...

2010-07-01

36

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

Code of Federal Regulations, 2012 CFR

...When must I conduct a static bottomhole pressure survey? 550.1153 Section 550...When must I conduct a static bottomhole pressure survey? (a) You must conduct a static bottomhole pressure survey under the following...

2012-07-01

37

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

Code of Federal Regulations, 2014 CFR

...When must I conduct a static bottomhole pressure survey? 550.1153 Section 550...When must I conduct a static bottomhole pressure survey? (a) You must conduct a static bottomhole pressure survey under the following...

2014-07-01

38

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

Code of Federal Regulations, 2013 CFR

...When must I conduct a static bottomhole pressure survey? 550.1153 Section 550...When must I conduct a static bottomhole pressure survey? (a) You must conduct a static bottomhole pressure survey under the following...

2013-07-01

39

Description of a pressure measurement technique for obtaining surface static pressures of a radial turbine  

NASA Technical Reports Server (NTRS)

The aerodynamic performance of a solid uncooled version of a cooled radial turbine was evaluated in the Small Engine Components Test Facility Turbine rig at the NASA Lewis Research Center. Specifically, an experiment was conducted to rotor surface static pressures. This was the first time surface static pressures had been measured on a radial turbine at NASA Lewis. These pressures were measured by a modified Rotating Data Package (RDP), a standard product manufactured by Scanivalve, Inc. Described here are the RDP, and the modifications that were made, as well as the checkout, installation, and testing procedures. The data presented are compared to analytical results obtained from NASA's MERIDL TSONIC BLAYER (MTSB) code.

Dicicco, L. Danielle; Nowlin, Brent C.; Tirres, Lizet

1992-01-01

40

Vesicourethral static pressure profile during voiding: Methodology and clinical utility  

Microsoft Academic Search

Searching for more direct urodynamic methods to accurately localize and assess the degree of bladder outlet obstructions, we have evaluated the role of micturitional vesicourethral static pressure profile measurements in clinical urodynamics. More than 400 patients, normal and abnormal, were studied with this technique over the past seven years. Details of the technique and the patterns of abnormalities are described

Subbarao V. Yalla; Neil M. Resnick

1984-01-01

41

Static pressure orifice system testing method and apparatus  

NASA Technical Reports Server (NTRS)

A method and apparatus are presented for pressure testing the static pressure orifices and associated connections used in wind tunnels. A cylindrical module, having in one end an open hemispherical calibration pressure chamber separated from and surrounded by an annular vacuum chamber is placed over the orifice of the system to be tested. O-rings ensure seating and a vacuum seal between the chambered end of the module and the surface around the orifice: one O-ring separates the outer chamber from the outside environment. Ports lead from each of the chambers out the other end of the module to tubes connected to a control box consisting of calibration pressure and vacuum supply lines, bleeder valves, and gauges.

Culotta, R. F.; Posey, D. L. (inventors)

1980-01-01

42

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

43

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

44

30 CFR 7.307 - Static pressure test.  

Code of Federal Regulations, 2012 CFR

...pressurization shall not exhibit— (i) Leakage through welds or casting; or (ii) Rupture of any part that affects the...pressurizing agent shall not exhibit— (i) Visible cracks in welds; (ii) Permanent deformation exceeding 0.040 inches...

2012-07-01

45

Static response of miniature capacitive pressure sensors with square or rectangular silicon diaphragm  

E-print Network

a compara- tive study of the sensitivity of piezoresistive and capacitive sensors to pressure and have shown505 Static response of miniature capacitive pressure sensors with square or rectangular silicon. 2014 The static response of capacitive pressure sensors with a thin rectangular or square diaphragm

Paris-Sud XI, Université de

46

Radio jet refraction in galactic atmospheres with static pressure gradients  

NASA Technical Reports Server (NTRS)

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

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

1981-01-01

47

Pressure and velocity profiles in a static mechanical hemilarynx model.  

PubMed

This study examined pressure and velocity profiles in a hemilarynx mechanical model of phonation. The glottal section had parallel walls and was fabricated from hard plastic. Twelve pressure taps were created in the vocal fold surface and connected to a differential pressure transducer through a pressure switch. The glottal gap was measured with feeler gauges and the uniform glottal duct was verified by use of a laser system. Eight pressure transducers were placed in the flat wall opposite the vocal fold. Hot-wire anemometry was used to obtain velocity profiles upstream and downstream of the glottis. The results indicate that the pressure distribution on the vocal fold surface was consistent with pressure change along a parallel duct, whereas the pressures on the opposite flat wall typically were lower (by 8%-40% of the transglottal pressure just past mid-glottis). The upstream velocity profiles were symmetric regardless of the constriction shape and size. The jet flow downstream of the glottis was turbulent even for laminar upstream conditions. The front of the jet was consistently approximately 1.5 mm from the flat wall for glottal gaps of 0.4, 0.8 and 1.2 mm. The turbulence intensity also remained approximately at the same location of about 4 mm from the flat wall for the two larger gaps. PMID:12509021

Alipour, Fariborz; Scherer, Ronald C

2002-12-01

48

Impacts of Static Pressure Set Level on the HVAC Energy Consumption and Indoor Conditions  

E-print Network

Air static pressure must be maintained at a certain level leaving the air-handing unit (AHU) to force a suitable amount of air through the terminal boxes. However, an excessive static pressure level is often used due to ( 1 ) lack of a control...

Liu, M.; Zhu, Y.; Claridge, D. E.; White, E.

1996-01-01

49

Warm Pressurant Gas Effects on the Static Bubble Point Pressure for Cryogenic LADs  

NASA Technical Reports Server (NTRS)

This paper presents experimental results for the liquid hydrogen and nitrogen bubble point tests using warm pressurant gases conducted at the NASA Glenn Research Center. The purpose of the test series was to determine the effect of elevating the temperature of the pressurant gas on the performance of a liquid acquisition device (LAD). Three fine mesh screen samples (325x2300, 450x2750, 510x3600) were tested in liquid hydrogen and liquid nitrogen using cold and warm non-condensable (gaseous helium) and condensable (gaseous hydrogen or nitrogen) pressurization schemes. Gases were conditioned from 0K - 90K above the liquid temperature. Results clearly indicate degradation in bubble point pressure using warm gas, with a greater reduction in performance using condensable over non-condensable pressurization. Degradation in the bubble point pressure is inversely proportional to screen porosity, as the coarsest mesh demonstrated the highest degradation. Results here have implication on both pressurization and LAD system design for all future cryogenic propulsion systems. A detailed review of historical heated gas tests is also presented for comparison to current results.

Hartwig, Jason W.; McQuillen, John; Chato, Daniel J.

2014-01-01

50

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

51

Effects of geometric scaling on static pressure measurements in orifice flow-meters  

E-print Network

EFFECTS OF GEOMETRIC SCALING ON STATIC PRESSURE MEASUREMENTS IN ORIFICE FLOW-METERS A Thesis by ARUNAVA SARKER Submitted to the Office of Graduate Studies of Texas A&M University in partial fulfillment of the requirements for the degree... of MASTER OF SCIENCE August 1993 Major Subject: Mechanical Engineering EFFECTS OF GEOMETRIC SCALING ON STATIC PRESSURE MEASUREMENTS IN ORIFICE FLOW-METERS A Thesis by ARUNAVA SARKER Approved as to style and content by: Gerald L. rri son (Chair...

Sarker, Arunava

2012-06-07

52

Hot-film static-pressure probe for surveying flow fields  

NASA Technical Reports Server (NTRS)

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.

1981-01-01

53

Instrumentation for measuring static pressure fluctuations within the atmospheric boundary layer  

Microsoft Academic Search

An instrument is described which is capable of making Eulerian measurements of microscale fluctuations in the static pressure when it is placed within the turbulent flow of the lower atmospheric boundary layer. The sampling ports are located on an accurately shaped streamlined circular disc; dynamic pressure changes at these ports, due to the flow fluctuations, are small when compared to

J. A. Elliott

1972-01-01

54

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

NASA Technical Reports Server (NTRS)

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

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

1987-01-01

55

Static pressure measurements in A 30 kWe class arcjet  

NASA Technical Reports Server (NTRS)

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

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

1991-01-01

56

Relationship between Entrainment and Static Pressure Field on 2-D Jets.  

NASA Astrophysics Data System (ADS)

It is well know that entrainment carried out in wakes and jets. This experimental study aimes at investigation the relationship between the entrainment and the pressure field in 2-D jet. The 2-D jet was generated by 2-D rectangular wind tunnel. The velocity and prressure fields were observed in order to investigate the free shear layer of jet. These value were measured by the x type hot-wire anemometer, LDV and the newly developed static pressure probe. Jet diffusion process is visualized by smoke wire method. The result of the experiment was that the static pressure fluctuated intensively, and was negative mean value because of the velocity intermittence in the free shear layer of the 2-D jet. It seems reasonable to suppose that entrainment occurs owing to the negative static pressure by the eddy motion and large scale convection in the free shear layer.

Kimura, M.; Ono, K.; Saima, A.

1996-11-01

57

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

NASA Astrophysics Data System (ADS)

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

2007-12-01

58

Laboratory manual for static pressure drop experiments in LMFBR wire wrapped rod bundles  

SciTech Connect

Purpose of this experiment is to determine both interior and edge subchannel axial pressure drops for a range of Reynolds numbers. The subchannel static pressure drop is used to calculate subchannel and bundle average friction factors, which can be used to verify existing friction factor correlations. The correlations for subchannel friction factors are used as input to computer codes which solve the coupled energy, continuity, and momentum equations, and are also used to develop flow split correlations which are needed as input to codes which solve only the energy equation. The bundle average friction factor is used to calculate the overall bundle pressure drop, which determines the required pumping power.

Burns, K.J.; Todreas, N.E.

1980-07-01

59

Measurements of mean static pressure and far field acoustics of shock containing supersonic jets  

NASA Astrophysics Data System (ADS)

The far field acoustic data base generated in studies of broadband shock noise from supersonic jets is presented. Both conical and contoured nozzles of exit Mach numbers 1.0, 1.5, and 2.0 were tested using unheated air at pressure ratios ranging from 1.9 to 14. Tests were performed both with and without screech suppression tabs. Overall sound pressure variations and representative 1/3-octave and narrowband spectra are presented. The mean static pressure measured within these jets is also surveyed.

Norum, T. D.; Seiner, J. M.

1982-09-01

60

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

PubMed

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

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

2013-09-24

61

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

62

Effect of static pressure on acoustic energy radiated by cavitation bubbles in viscous liquids under ultrasound.  

PubMed

The effect of static pressure on acoustic emissions including shock-wave emissions from cavitation bubbles in viscous liquids under ultrasound has been studied by numerical simulations in order to investigate the effect of static pressure on dispersion of nano-particles in liquids by ultrasound. The results of the numerical simulations for bubbles of 5 ?m in equilibrium radius at 20 kHz have indicated that the optimal static pressure which maximizes the energy of acoustic waves radiated by a bubble per acoustic cycle increases as the acoustic pressure amplitude increases or the viscosity of the solution decreases. It qualitatively agrees with the experimental results by Sauter et al. [Ultrason. Sonochem. 15, 517 (2008)]. In liquids with relatively high viscosity (?200 mPa s), a bubble collapses more violently than in pure water when the acoustic pressure amplitude is relatively large (?20 bar). In a mixture of bubbles of different equilibrium radius (3 and 5 ?m), the acoustic energy radiated by a 5 ?m bubble is much larger than that by a 3 ?m bubble due to the interaction with bubbles of different equilibrium radius. The acoustic energy radiated by a 5 ?m bubble is substantially increased by the interaction with 3 ?m bubbles. PMID:22087995

Yasui, Kyuichi; Towata, Atsuya; Tuziuti, Toru; Kozuka, Teruyuki; Kato, Kazumi

2011-11-01

63

Quasi-static vapor pressure measurements on reactive systems in inert atmosphere box  

NASA Technical Reports Server (NTRS)

Apparatus makes vapor pressure measurements on air-sensitive systems in an inert atmosphere glove box. Once the apparatus is loaded with the sample and all connections made, all measuring operations may be performed outside the box. The apparatus is a single-tube adaptation of the double-tube quasi-static technique.

Fischer, A. K.

1968-01-01

64

ROLE OF STATIC LOAD (OVERBURDEN) PRESSURE IN COALIFICATION OF BITUMINOUS AND ANTHRACITIC COAL.  

USGS Publications Warehouse

Tissue from a calcite concretion (coal ball) and attached coal of semianthracite rank from the Belgium Bouxharmont coal bed were analyzed separately by elemental chemical, **1**3C nuclear magnetic resonance, reflectance, and paleobotanical techniques to compare relative degrees of coalification. The results indicate that static load pressure has no perceptible effect on coalification up to and including a rank of semianthracite.

Lyons, P.C.; Hatcher, P.G.; Brown, F.W.; Krasnow, M.R.; Larson, R.R.; Millay, M.A.

1985-01-01

65

Static Pressure Losses in 6, 8, and 10-inch Non-Metallic Flexible Ducts  

E-print Network

This study measured airflow static pressure losses through non-metallic flexible ducts in compliance with ASHRAE Standard 120-1999, Methods of Testing to Determine Flow Resistance of HVAC Air Ducts and Fittings (ASHRAE 1999). Duct sizes of 6, 8...

Weaver, K.; Culp, C.

2006-01-01

66

Determination of the Thermodynamic Scaling Exponent from Static, Ambient-Pressure Quantities  

E-print Network

An equation is derived that expresses the thermodynamic scaling exponent, g, which superposes relaxation times and other measures of molecular mobility determined over a range of temperatures and densities, in terms of static, physical quantities. The latter are available in the literature or can be measured at ambient pressure. We show for 13 materials, both molecular liquids and polymers, that the calculated g are equivalent to the scaling exponents obtained directly by superpositioning. The assumptions of the analysis are that the glass transition is isochronal and that the first Ehrenfest relation is valid; the first assumption is true by definition, while the second has been corroborated for many glass-forming materials at ambient pressure. However, we find that the Ehrenfest relation breaks down at elevated pressure, although this limitation is of no consequence herein, since the appeal of the new equation is its applicability to ambient pressure data.

R. Casalini; C. M. Roland

2014-03-18

67

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

NASA Technical Reports Server (NTRS)

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

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

1995-01-01

68

Determination of the Thermodynamic Scaling Exponent for Relaxation in Liquids from Static Ambient-Pressure Quantities  

NASA Astrophysics Data System (ADS)

An equation is derived that expresses the thermodynamic scaling exponent, ?, which superposes relaxation times ? and other measures of molecular mobility determined over a range of temperatures and densities, in terms of static physical quantities. The latter are available in the literature or can be measured at ambient pressure. We show for 13 materials, both molecular liquids and polymers, that the calculated ? are equivalent to the scaling exponents obtained directly by superpositioning. The assumptions of the analysis are that the glass transition Tg is isochronal (i.e., ?? is constant at Tg, which is true by definition) and that the pressure derivative of the glass temperature is given by the first Ehrenfest relation. The latter, derived assuming continuity of the entropy at the glass transition, has been corroborated for many glass-forming materials at ambient pressure. However, we find that the Ehrenfest relation breaks down at elevated pressure; this limitation is of no consequence herein, since the appeal of the new equation is its applicability to ambient-pressure data. The ability to determine, from ambient-pressure measurements, the scaling exponent describing the high-pressure dynamics extends the applicability of this approach to a broader range of materials. Since ? is linked to the intermolecular potential, the new equation thus provides ready access to information about the forces between molecules.

Casalini, R.; Roland, C. M.

2014-08-01

69

Spectral scaling of static pressure fluctuations in the atmospheric surface layer: The interaction between large and small scales  

E-print Network

Spectral scaling of static pressure fluctuations in the atmospheric surface layer: The interaction, University of Iowa, Iowa City, Iowa 52242 Received 17 March 1997; accepted 2 February 1998 Static pressure fluctuations measured in the atmospheric surface layer over a grass covered forest clearing are studied

Katul, Gabriel

70

Effects of inlet distortion on a static pressure probe mounted on the engine hub in an F-15 airplane  

NASA Technical Reports Server (NTRS)

An inlet static pressure (PS2) probe was mounted on the hub of an F100 engine in an F-15 airplane. Flight test results showed that for low distortion conditions, the ratio of engine-face total pressure to static pressure agreed well with previous altitude facility data. Off-schedule operation of the inlet third ramp angle caused increased distortion of the inlet airflow during steady-state flight conditions. Data are shown for inlet third ramp excursions leading to engine stall. The relationships of inlet face total to static pressure ratio as a function of several distortion descriptors are also described.

Hughes, D. L.; Myers, L. P.; Mackall, K. G.

1985-01-01

71

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

PubMed Central

Aim was to elucidate autonomic responses to dynamic and static (isometric) exercise of the lower limbs eliciting the same moderate heart rate (HR) response. Method: 23 males performed two kinds of voluntary exercise in a supine position at similar heart rates: static exercise (SE) of the lower limbs (static leg press) and dynamic exercise (DE) of the lower limbs (cycling). Subjective effort, systolic (SBP) and diastolic blood pressure (DBP), mean arterial pressure (MAP), rate pressure product (RPP) and the time between consecutive heart beats (RR-intervals) were measured. Time-domain (SDNN, RMSSD), frequency-domain (power in the low and high frequency band (LFP, HFP)) and geometric measures (SD1, SD2) as well as non-linear measures of regularity (approximate entropy (ApEn), sample entropy (SampEn) and correlation dimension D2) were calculated. Results: Although HR was similar during both exercise conditions (88±10 bpm), subjective effort, SBP, DBP, MAP and RPP were significantly enhanced during SE. HRV indicators representing overall variability (SDNN, SD 2) and vagal modulated variability (RMSSD, HFP, SD 1) were increased. LFP, thought to be modulated by both autonomic branches, tended to be higher during SE. ApEn and SampEn were decreased whereas D2 was enhanced during SE. It can be concluded that autonomic control processes during SE and DE were qualitatively different despite similar heart rate levels. The differences were reflected by blood pressure and HRV indices. HRV-measures indicated a stronger vagal cardiac activity during SE, while blood pressure response indicated a stronger sympathetic efferent activity to the vessels. The elevated vagal cardiac activity during SE might be a response mechanism, compensating a possible co-activation of sympathetic cardiac efferents, as HR and LF/HF was similar and LFP tended to be higher. However, this conclusion must be drawn cautiously as there is no HRV-marker reflecting “pure” sympathetic cardiac activity. PMID:24349546

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

2013-01-01

72

Improvement of Young modulus estimation by ultrasound using static pressure steps  

NASA Astrophysics Data System (ADS)

In this work the radial displacement of the arterial wall is measured using a cross correlation algorithm. An elastic model for static pressure conditions is developed, fit to the boundary conditions of the physical problem. Measuring the wall displacements as pressure changes the biomechanical behavior of the arterial wall can be characterized. Validation measurements were performed in a calibrated latex tube. The obtained experimental results are in good agreement with the theoretical model. Human arteries were also characterized. The typical non linear pressure-diameter behavior due to the presence of elastine and collagen was observed. Human arteries with atheroma plaques were also studied presenting a different Young modulus than the healthy ones. From these results we conclude that this method could be used in the characterization of arterial mechanical alterations and/or in the post-implant biomechanical evaluation of vascular grafts.

Brum, J.; Balay, G.; Bia, D.; Benech, N.; Ramos, A.; Armentano, R.; Negreira, C.

2010-01-01

73

Analysis of Fluctuating Static Pressure Measurements in the National Transonic Facility  

NASA Technical Reports Server (NTRS)

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

Igoe, William B.

1996-01-01

74

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

SciTech Connect

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

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

2010-01-22

75

Characteristics of a wedge with various holder configurations for static-pressure measurements in subsonic gas streams  

NASA Technical Reports Server (NTRS)

The characteristics of a wedge static-pressure sensing element with various holder configurations were determined and compared with the characteristics of the conventional tube. The probes were tested over a range of Mach number from 0.3 to 0.95 and at various pitch and yaw angles. The investigation showed that the spike-mounted wedge sensing element has a pressure coefficient comparable with the conventional subsonic static-pressure probe and the pressure coefficient of the wedge varied less than that of the conventional probe for corresponding change of yaw angle.

Gettelman, Clarence C; Krause, Lloyd N

1951-01-01

76

Application of Wireless Sensor Network (WSN) Technologies in Optimal Static Pressure Reset in Variable Air Volume (VAV) System  

E-print Network

unit damper position based, outside air temperature based and air flow based, and proposed an optimal static pressure reset method. Subsequently, hourly simulations of a building in Omaha, Nebraska, USA, was implemented and validated that the VAV system...

Zheng, K.; Li, H.; Yang, H.

2007-01-01

77

Optimized Fan Control In Variable Air Volume HVAC Systems Using Static Pressure Resets: Strategy Selection and Savings Analysis  

E-print Network

The potential of static pressure reset (SPR) control to save fan energy in variable air volume HVAC systems has been well documented. Current research has focused on the creation of reset strategies depending on specific system features...

Kimla, John

2010-07-14

78

Bounds on pressure profile and internal compactness of static perfect fluid spheres with a positive cosmological constant  

E-print Network

Some theorems for a static prefect fluid sphere, i.e. a star, in the presence of a positive cosmological constant are proved. These theorems put bounds on the pressure profile and internal compactness of the star.

F. Shojai; A. Shojai; M. Mousavi

2014-02-04

79

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

80

Estimation of the quasi-static Young's modulus of the eardrum using a pressurization technique.  

PubMed

The quasi-static Young's modulus of the eardrum's pars tensa is an important modeling parameter in computer simulations. Recent developments in indentation testing and inverse modeling allow estimation of this parameter with the eardrum in situ. These approaches are challenging because of the curved shape of the pars tensa which requires special care during experimentation to keep the indenter perpendicular to the local surface at the point of contact. Moreover, they involve complicated contact modeling. An alternative computer-based method is presented here in which pressurization is used instead of indentation. The Young's modulus of a thin-shell model of the eardrum with subject-specific geometry is numerically optimized such that simulated pressurized shapes match measured counterparts. The technique was evaluated on six healthy rat eardrums, resulting in a Young's modulus estimate of 22.8±1.5MPa. This is comparable to values estimated using indentation testing. The new pressurization-based approach is simpler to use than the indentation-based method for the two reasons noted above. PMID:23270964

Ghadarghadar, Nastaran; Agrawal, Sumit K; Samani, Abbas; Ladak, Hanif M

2013-06-01

81

Analysis of static and wave-induced pore pressures in marine sediments  

E-print Network

) are presented and analyzed. The piezometer measured hydrostatic pressu, e at 10 ft (3 m) below the mudli ne, pore water pressure at 41 ft (12 m) below the mudline (using a high air entry stun ), and pore ga" pressure at 10 and 41 ft '(3 and 12 m) below...; DAYS 337 -341 EXCESS PORE PRESSURE MEASUREMENTS; DAYS 342-354 DECAY OF INDUCED EXCESS PORE PRESS'. ::RES FOLLOWING IiNSTALLATION INITIAL EXCESS PORE PRESSURES AND CALCULATED OVERBURDEN PRESSURES VERSUS DEP1H; SEASWAB II HYDROSTATIC AND TOTAL PORE...

Williams, Garrett Edwin

2012-06-07

82

Granular Arch Shapes in Storage Silo Determined by Quasi-static Analysis under Uniform Vertical Pressure  

NASA Astrophysics Data System (ADS)

Janssen's bin effect has a great impact to a wide range of engineering applications and theoretical developments which relate to granular materials. The problem of storage silo under uniform vertical pressure exerting on horizontal cross section was investigated in two-dimensional system of equilibrium. Two choices of vertical plane where a ratio of radial stress to normal stress is constant are considered based on Janssen's approach as well as Jaky's approach. Exact stress solutions based on both approaches are generalized in cylindrical coordinates and are validated with boundary conditions at the top layer and at the great depth of silo. Despite of similar solutions obtained at the great depth, it was found that a constant coefficient of lateral pressure must be applied to the center line as suggested by Jaky, implying storage silo is stable in at-rest state. Then, the arch shapes formation in granular materials stored in silo was analyzed by quasi-statics under Jaky's approach. It was found that stacks of arch appear in variable shapes for different depths but tend to curve like catenary shape at the great depth.

Pipatpongsa, Thirapong; Heng, Sokbil

83

The development of large diameter, high pressure, cryogenic radial static seals  

NASA Technical Reports Server (NTRS)

Two configurations of radial static seals are developed for high-pressure 773 kg per sq cm cryogenic applications: a U-shaped fluorocarbon seal and a delta-shaped PTFE seal. The U-seal is a common commercial design consisting of a spring-loaded cup-shaped jacket; the basic principle is that the soft plastic jacket provides the interface between the piston and the bore, the jacket being held in place by a metal spring. The delta seal is based on the principle that the soft plastic delta cross section furnishes the interface at the metal face and circumferential face of the gland and cylinder. Test results indicate that both the plastic U-seal and the delta seal designs are sufficiently flexible to accommodate assembly in bore or piston grooves. Of these two configurations, the delta seal is found to be superior as it meets all the design requirements for proof pressure testing the turbopump components of the main engine in the Space Shuttle.

Burr, M. E.

1976-01-01

84

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

85

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 ...

86

Structural Phase Stability in Group IV Metals Under Static High Pressure  

NASA Astrophysics Data System (ADS)

In group IV metals (Ti, Zr, and Hf) room temperature compression leads to a martensitic transformation from a ductile ? to a brittle ? phase. The ??? phase boundary decreases to lower pressure at high temperature and can limit the use of group IV metals in industrial applications. There is a large discrepancy in the transition pressure reported in literature, with some of the variation attributed to experimental conditions (i.e. hydrostatic vs. non-hydrostatic). Shear deformation in non-hydrostatic experiments drives ??? transition and decreases transition pressure. Impurities can also aid or suppress ??? 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 ??? transition and stabilize ? phase to higher pressure. We also show that reduction in grain size can also influence ?-? phase boundary and help stabilize ? phase to higher pressure under non-hydrostatic conditions.

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

2009-12-01

87

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

NASA Astrophysics Data System (ADS)

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

Liao, JianHui; Zhuang, Zhuo

2012-04-01

88

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

NASA Technical Reports Server (NTRS)

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

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

1982-01-01

89

Under Pressure: Your Blood Pressure  

NSDL National Science Digital Library

During this lesson, learners will determine their blood pressure and learn about systolic and diastolic pressures. They also investigate how blood pressure works with an activity that uses a balloon and a film canister, and learn about factors that contribute to high blood pressure.

Science Museum of Minnesota

2000-01-01

90

Pressure &Pressure & TemperatureTemperature  

E-print Network

Pressure &Pressure & TemperatureTemperature vs.vs. AltitudeAltitude #12;Presented by:Presented by ­ February 22, 2003 #12;Why We Did It?Why We Did It? z Measure the pressure in relation to altitude z MeasureProLabProLabProLabPro to record data, pressureto record data, pressureto record data, pressureto record data, pressure probe

California at Santa Cruz, University of

91

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

NASA Technical Reports Server (NTRS)

Samples of Barre granite have been creep tested at room temperature at confining pressures up to 2 kbar. Experimental procedures are described and the results of observations and analysis are presented. It is noted that the effect of pressure is to increase the amount of inelastic deformation the rock can sustain before becoming unstable. It is also shown that this increased deformation is due to longer and more numerous microcracks.

Kranz, R. L.

1980-01-01

92

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

93

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

94

Pressure ulcer  

MedlinePLUS

... that area. Use pillows, special foam cushions, and sheepskin to reduce the pressure. Treat the sore as ... Use items that can help reduce pressure -- pillows, sheepskin, foam padding, and powders from medical supply stores. ...

95

Pressure Sores  

MedlinePLUS

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

96

Peer Pressure  

MedlinePLUS

... for the school play. Back Continue When the Pressure's On Sometimes, though, the stresses in your life ... the ability to make good decisions. Back Continue Pressure Pointers Nearly everyone ends up in a sticky ...

97

Air Pressure  

NSDL National Science Digital Library

In this experiment, learners use a blow dryer and water bottle to observe and record changes in air pressure caused by changes in temperature. Educators can use this activity to explain how changes in temperature cause changes in air pressure which cause wind. This activity guide contains background information on air pressure, instructions for an extension experiment, and links to useful online resources.

Illinois, University O.

2009-01-01

98

Feeling Pressured  

NSDL National Science Digital Library

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

Eric Muller

1998-01-01

99

Static internal pressure capacity of Hanford Single-Shell Waste Tanks  

SciTech Connect

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

Julyk, L.J.

1994-07-19

100

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

SciTech Connect

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

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

2010-12-03

101

Binding of curcumin to milk proteins increases after static high pressure treatment of skim milk.  

PubMed

Curcumin is a bioactive polyphenolic compound extracted from turmeric with known anti-inflammatory properties, and its hydrophobic nature restricts its solubility and its bioaccessibility. Solubility may be improved upon binding of curcumin to native or treatment-modified casein micelles. The present work demonstrated that high hydrostatic pressure treatment of skim milk increases the binding of curcumin to caseins. The association of curcumin to casein micelles was assessed using fluorescence spectroscopy, either directly or by tryptophan quenching. The amount of curcumin associated with the milk proteins increased in pressure-treated milk, and a further improvement in the amount of bound curcumin was observed upon pressure treatment of a milk/curcumin mixture. However, in this case, some of the curcumin dissociated during storage, contrarily to what was observed for untreated milk. From a molecular standpoint, the data presented here indicate that structural modifications induced by high-pressure treatment and known to affect the structure of milk proteins result in a rearrangement of the amino acid residues in close proximity to the protein-associated curcumin. PMID:23552051

Rahimi Yazdi, Saeed; Bonomi, Francesco; Iametti, Stefania; Miriani, Matteo; Brutti, Andrea; Corredig, Milena

2013-05-01

102

Shock and static pressure demagnetization of pyrrhotite and implications for the Martian crust  

Microsoft Academic Search

The absence of crustal magnetization around young impact basins suggests impact demagnetization of vast regions of the crust after the cessation of the Martian dynamo. Attempts to understand the impact demagnetization process and to infer the magnetic properties (e.g., the carrier phase) of the Martian crust have been based on the experimental pressure demagnetization of magnetic rocks and minerals. We

Karin L. Louzada; Sarah T. Stewart; Benjamin P. Weiss; Jérôme Gattacceca; Natalia S. Bezaeva

2010-01-01

103

Selection and static calibration of the Marsh J1678 pressure gauge  

NASA Technical Reports Server (NTRS)

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

Oxendine, Charles R.; Smith, Howard W.

1993-01-01

104

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

PubMed

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

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

2012-02-01

105

Temperatures in the earth's core from melting-point measurements of iron at high static pressures  

Microsoft Academic Search

The most reliable method for determining the temperature gradient at the earth's core is the estimation of Fe and Fe-rich compounds' melting temperature at the pressure of the inner core boundary. Attention is presently given to melting-point measurements on Fe and Fe-O compounds at up to 2 Mbar. An extrapolation of these results to 3.3 Mbar yields an inner core

R. Boehler

1993-01-01

106

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.

107

Under Pressure  

NSDL National Science Digital Library

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

History, American M.

2002-01-01

108

Impacts of Static Pressure Reset on VAV System Air Leakage, Fan Power and Thermal Energy - Part 2: Case Demonstration for a Typical Climate System  

E-print Network

Impacts of Static Pressure Reset on VAV System Air Leakage, Fan Power and Thermal Energy Part 2: Case Demonstration for a Typical Climate System Mingsheng Liu Keke Zheng Lixia Wu Zhan Wang Craig Johnson Professor...

Liu, M.; Zheng, K.; Wu, L.; Wang, Z.; Johnson, C.

2007-01-01

109

Pressure ulcers  

PubMed Central

Introduction Unrelieved pressure or friction of the skin, particularly over bony prominences, can lead to pressure ulcers in up to a third of people in hospitals or community care, and a fifth of nursing home residents. Pressure ulcers are more likely in people with reduced mobility and poor skin condition, such as older people or those with vascular disease. Methods and outcomes We conducted a systematic review and aimed to answer the following clinical questions: What are the effects of preventive interventions in people at risk of developing pressure ulcers? What are the effects of treatments in people with pressure ulcers? We searched: Medline, Embase, The Cochrane Library and other important databases up to February 2007 (BMJ Clinical Evidence reviews are updated periodically, please check our website for the most up-to-date version of this review). We included harms alerts from relevant organisations such as the US Food and Drug Administration (FDA) and the UK Medicines and Healthcare products Regulatory Agency (MHRA). Results We found 60 systematic reviews, RCTs, or observational studies that met our inclusion criteria. We performed a GRADE evaluation of the quality of evidence for interventions. Conclusions In this systematic review we present information relating to the effectiveness and safety of the following interventions: air-filled vinyl boots, air-fluidised supports, alternating pressure surfaces (including mattresses), alternative foam mattresses, constant low-pressure supports, debridement, electric profiling beds, electrotherapy, hydrocellular heel supports, low-air-loss beds (including hydrotherapy beds), low-level laser therapy, low-tech constant low-pressure supports, medical sheepskin overlays, nutritional supplements, orthopaedic wool padding, pressure-relieving overlays on operating tables, pressure-relieving surfaces, repositioning (regular "turning"), seat cushions, standard beds, standard care, standard foam mattresses, standard tables, surgery, therapeutic ultrasound, topical lotions and dressings, topical negative pressure, and topical phenytoin. PMID:19450317

2008-01-01

110

Pressure ulcers  

PubMed Central

Introduction Unrelieved pressure or friction of the skin, particularly over bony prominences, can lead to pressure ulcers in up to one third of people in hospitals or community care, and one fifth of nursing home residents. Pressure ulcers are more likely in people with reduced mobility and poor skin condition, such as older people or those with vascular disease. Methods and outcomes We conducted a systematic review and aimed to answer the following clinical questions: What are the effects of preventive interventions in people at risk of developing pressure ulcers? What are the effects of treatments in people with pressure ulcers? We searched: Medline, Embase, The Cochrane Library, and other important databases up to June 2010 (Clinical Evidence reviews are updated periodically, please check our website for the most up-to-date version of this review). We included harms alerts from relevant organisations such as the US Food and Drug Administration (FDA) and the UK Medicines and Healthcare products Regulatory Agency (MHRA). Results We found 64 systematic reviews, RCTs, or observational studies that met our inclusion criteria. We performed a GRADE evaluation of the quality of evidence for interventions. Conclusions In this systematic review we present information relating to the effectiveness and safety of the following interventions: air-filled vinyl boots, air-fluidised supports, alternating-pressure surfaces (including mattresses), alternative foam mattresses, constant low-pressure supports, debridement, electric profiling beds, electrotherapy, hydrocellular heel supports, low-air-loss beds (including hydrotherapy beds), low-level laser therapy, low-tech constant-low-pressure supports, medical sheepskin overlays, nutritional supplements, orthopaedic wool padding, pressure-relieving overlays on operating tables, pressure-relieving surfaces, repositioning (regular "turning"), seat cushions, standard beds, standard care, standard foam mattresses, standard tables, surgery, therapeutic ultrasound, topical lotions and dressings, topical negative pressure, and topical phenytoin. PMID:21524319

2011-01-01

111

Pressure Measurement  

NASA Technical Reports Server (NTRS)

Pressure Systems, Inc.'s DPT 6400 is a system designed to increase productivity in industrial processes where there is a need for making multiple pressure measurements quickly and with high accuracy. It is applicable in controlling industrial processes in plants that are being upgraded to automated status. In order to automate such plants the pressures at the many loops must be measured, converted to digital information and transmitted to the plant's process control computer. The DPT 6400 serves that function. By employing solid-state pressure sensing transducers whose errors are automatically corrected by a microprocessor, it is capable of highly accurate pressure measurements. Basic DPT 6400 has 64 channels, but the system can be expanded to 256 channels by the addition of "slave" units.

1982-01-01

112

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. PMID:22031747

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

113

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

SciTech Connect

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

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

1999-12-01

114

Pressure Activity  

NSDL National Science Digital Library

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

115

Intracranial pressure  

Microsoft Academic Search

Background: The effects of pneumoperitoneum on intracranial pressure (ICP) have received relatively little attention. This study was\\u000a undertaken to investigate the changes in ICP occurring as a result of increased intraabdominal pressure (IAP) and positioning\\u000a in animals with normal and elevated ICP.\\u000a \\u000a \\u000a \\u000a \\u000a \\u000a Method: Five pigs (average weight 60 lb) were studied. A subarachnoid screw was placed for ICP monitoring. End

R. J. Rosenthal; J. R. Hiatt; E. H. Phillips; W. Hewitt; A. A. Demetriou; M. Grode

1997-01-01

116

Influence of static pressure on dynamic characteristics of laser-induced cavitation and hard-tissue ablation under liquid environment  

NASA Astrophysics Data System (ADS)

Several studies have demonstrated that laser-induced hard tissue ablation effects can be enhanced by applying an additional water-layer on tissue surface. However, the related mechanism has not yet been presented clearly. In this paper, the influence of static pressure on dynamic characteristics of cavitation induced by pulse laser in liquid and its effect on bovine shank bone ablation were investigated. The laser source is fiber-guided free-running Ho:YAG laser with wavelength of 2080 nm, pulse duration of 350 ?s and energy of 1600 mJ. The tissue samples were immerged in pure water at different depths of 11, 16, 21, 26 and 31 mm. The working distance between the fiber tip and tissue surface was fixed at 1 mm for all studies. The dynamic interaction between laser, water and tissue were recorded by high-speed camera, and the morphological changes of bone tissue were assessed by stereomicroscope and OCT. The results showed that many times expansion and collapse of bubble were observed, more than four pulsation periods were accurately achieved with the most energy deposited in the first period and the bubble became more and more irregular in shape. The longitudinal length (7.49--6.74 mm) and transverse width (6.69--6.08 mm) of bubble were slowly decreased while volume (0.0586--0.0124 mm3) of ablation craters were drastically reduced, with static pressure increasing. The results also presented that the water-layer on hard-tissue surface can not only reduce thermal injury but also improve lubricity of craters, although the water-layer reduced ablation efficiency.

Chen, Chuanguo; Li, Xuwei; Zhang, Xianzeng; Zhan, Zhenlin; Xie, Shusen

2014-11-01

117

Under Pressure  

NSDL National Science Digital Library

In this simple activity, learners discover how a mere piece of paper can be used to hold up the weight of a heavy book. Learners are encouraged to modify their materials, using the steps of the design process, to explore how such modification changes the amount of pressure paper can withstand. This inexpensive activity is great used with engineering or architecture units.

Wgbh

2007-01-01

118

Pressurized hopper  

Microsoft Academic Search

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

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

1980-01-01

119

Osmotic Pressure  

Microsoft Academic Search

As Mr. Whetham has called attention in your columns to my attempt to give a mechanical hypothesis for osmotic pressure, in the October number of the Philosophical Magazine, perhaps you will allow me to give some explanation of my somewhat faulty use of the term ``dissociation hypothesis,'' which, as Prof. Ramsay has pointed out to me, may easily be misunderstood.

J. H. Poynting

1896-01-01

120

Abnormal pressures as hydrodynamic phenomena  

USGS Publications Warehouse

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

Neuzil, C.E.

1995-01-01

121

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

122

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

123

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. 7 figs.

Anderson, T.T.; Roop, C.J.; Schmidt, K.J.; Gunchin, E.R.

1987-02-13

124

Blood pressure measurement  

MedlinePLUS

Diastolic blood pressure; Systolic blood pressure; Blood pressure reading; Measuring blood pressure ... your health care provider will wrap the blood pressure cuff snugly around your upper arm. The lower ...

125

Hypertension (High Blood Pressure)  

MedlinePLUS

... they think about their blood pressure. Understanding Blood Pressure Every person needs blood pressure to live. Without ... women get this condition. How Does High Blood Pressure Affect the Body? High blood pressure adds to ...

126

Cracking of pebbles in sediments (SE Vienna Basin, Austria): Lithostatic pressure versus static stress change  

NASA Astrophysics Data System (ADS)

We investigated brittle fractures in pebbles that are frequently radially cracked at indentation sites, in unconsolidated sediments within a gravel pit south of St. Margarethen (Burgenland, Austria). The outcrop is located in the Neogene Eisenstadt-Sopron Basin, which is a sub-basin on the SE border of the Vienna Basin. The sediments, which were deposited during the Sarmartian and Pannonian, represent a succession of deltaic gravels with intercalations of shallow-marine calcareous sands. The overburden on the exposed sediments never exceeded 200m. Extensional tectonics in these sediments resulted in the generation of conjugate sets of predominately WNW- and subordinate ESE-dipping normal faults. These faults were primarily localized in meter-thick gravel layers and, with increasing displacement, eventually crosscut other lithologies. The gravel layers contain a significant number of cracked pebbles. Detailed structural mapping revealed that these are not uniformly distributed: The abundance is higher within layers of matrix-free, well sorted gravels, but also seems to be related to the mechanics of faulting within the sediment. In order to find the controlling factors for the localization of pebble fracturing, grain-size distribution and shape and the number of point contacts of the pebbles were statistically measured. The results were then used as input parameters for numerical modelling. The Discrete Element Method (PFC3D, Itasca Cons.) was applied to simulate the effect of overburden on a certain volume of particles (i.e. the pebbles). The magnitude and the distribution of contact forces between the particles were observed and compared with the fracture resistance of natural pebbles, determined by point load testing in the laboratory. Results from numerical modelling indicate that the estimated maximum overburden of 200m would not have been able to generate contact forces high enough to crack a significant number of pebbles. We therefore conclude that cracking was related to static stress changes caused by fault-slip.

Tuitz, C.; Exner, U.; Grasemann, B.; Preh, A.

2009-04-01

127

Humidity and Pressure Regulation in a PEM Fuel Cell Using a Gain-Scheduled Static Feedback Controller  

Microsoft Academic Search

In this paper, the pressure difference between the anode and cathode compartments of a polymer electrolyte membrane (PEM) fuel cell stack is regulated along with the anode and cathode humidities using an anode recirculation system. The pressure regulation requirement stems from membrane safety considerations. The regulation of average humidities in the two compartments is a necessary (although not a sufficient)

Amey Y. Karnik; Jing Sun; Anna G. Stefanopoulou; Julia H. Buckland

2009-01-01

128

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

NASA Technical Reports Server (NTRS)

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

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

1985-01-01

129

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

PubMed Central

In contrast to western countries, foot complaints are rare in Africa. This is remarkable, as many African adults walk many hours each day, often barefoot or with worn-out shoes. The reason why Africans can withstand such loading without developing foot complaints might be related to the way the foot is loaded. Therefore, static foot geometry and dynamic plantar pressure distribution of 77 adults from Malawi were compared to 77 adults from the Netherlands. None of the subjects had a history of foot complaints. The plantar pressure pattern as well as the Arch Index (AI) and the trajectory of the center of pressure during the stance phase were calculated and compared between both groups. Standardized pictures were taken from the feet to assess the height of the Medial Longitudinal Arch (MLA). We found that Malawian adults: (1) loaded the midfoot for a longer and the forefoot for a shorter period during roll off, (2) had significantly lower plantar pressures under the heel and a part of the forefoot, and (3) had a larger AI and a lower MLA compared to the Dutch. These findings demonstrate that differences in static foot geometry, foot loading, and roll off technique exist between the two groups. The advantage of the foot loading pattern as shown by the Malawian group is that the plantar pressure is distributed more equally over the foot. This might prevent foot complaints. PMID:23468936

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

2013-01-01

130

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

2013-01-01

131

Normal Pressure Hydrocephalus (NPH)  

MedlinePLUS

Normal Pressure Hydrocephalus (NPH) Tweet Normal pressure hydrocephalus is a brain disorder in which excess cerebrospinal fluid accumulates in ... About Symptoms Diagnosis Causes & risks Treatments About Normal Pressure Hydrocephalus Normal pressure hydrocephalus occurs when excess cerebrospinal ...

132

Understanding Blood Pressure Readings  

MedlinePLUS

Understanding Blood Pressure Readings Updated:Nov 17,2014 Blood pressure is typically recorded as two numbers, written as a ratio like ... What is the AHA recommendation for healthy blood pressure? This chart reflects blood pressure categories defined by ...

133

Normal Pressure Hydrocephalus  

MedlinePLUS

NINDS Normal Pressure Hydrocephalus Information Page Synonym(s): Hydrocephalus - Normal Pressure Table of Contents (click to jump to sections) What ... Trials Organizations Additional resources from MedlinePlus What is Normal Pressure Hydrocephalus? Normal pressure hydrocephalus (NPH) is an ...

134

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

135

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

136

Determination of 2-methylisoborneol and geosmin in aqueous samples by static headspace-gas chromatography-mass spectrometry with ramped inlet pressure.  

PubMed

A method for determining the earthy and musty odors 2-methylisoborneol (2-MIB) and geosmin in drinking water using static headspace-GC-MS is described. To achieve lower detection limits, split ratio was optimized with ramped inlet pressure for large headspace sampling volume. The ramped inlet pressure, which held higher pressure (higher column flow rate) only during injection, allowed us to inject 3-mL volume to GC with very low split ratio (2:1). Although sequential analysis with a stainless steel ion source often changed the mass spectrum of 2-MIB, this spectral change was eliminated by using an inert ion source with a 6 mm drawout plate. The detection limits of this method were 0.36 and 0.14 ng/L, respectively, for 2-MIB and geosmin. The repeatabilities (n = 30) were 6.6 and 4.8%, respectively, at 1 ng/L for 2-MIB and geosmin. PMID:16405182

Nakamura, Sadao; Sakui, Norihiro; Tsuji, Akira; Daishima, Shigeki

2005-12-01

137

The variation in static pressure along the shell (lower part of the figure) also agrees well with the ex-periment. Points 3 are the pressure measured along the wall of the shell and points 4 are the pressure found  

E-print Network

of flow in ejector nozzles," Izv. Akad. Nauk SSSR, Mekh. Zhidk. Gaza, No. 1 (1974). W. L. Chow and A. L, "Calculation of the base pressure in ejector nozzles of different lengths at a zero coefficient of ejection). SIMILARITY OF FLOWS IN STRONGLY UNDEREXPANDED JETS OF VISCOUS GAS V. N. Gusev, T. V. Klimova, and V. V

Riabov, Vladimir V.

138

Active Mass Under Pressure  

E-print Network

After a historical introduction to Poisson's equation for Newtonian gravity, its analog for static gravitational fields in Einstein's theory is reviewed. It appears that the pressure contribution to the active mass density in Einstein's theory might also be noticeable at the Newtonian level. A form of its surprising appearance, first noticed by Richard Chase Tolman, was discussed half a century ago in the Hamburg Relativity Seminar and is resolved here.

Juergen Ehlers; Istvan Ozsvath; Engelbert Schucking

2005-05-10

139

Static and dynamic characteristics for a two-axial-groove bearing and a pressure-dam bearing  

E-print Network

bearing .........................................................................16 Fig. 8 Test bearing with pressure-dam at the unloaded pad.............................................17 Fig. 9 Rotor frequency spectrum at 12,000 rpm rotor speed...-coupled direct dynamic stiffness .................................................37 Fig. 20 Baseline imaginary dynamic stiffness ................................................................38 Fig. 21 Dynamic stiffness at 6000 rpm and 345k...

Al Jughaiman, Bader K.

2009-06-02

140

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,...

141

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

EPA Science Inventory

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

142

Do pressure relief cushions really relieve pressure?  

PubMed

In a laboratory setting, interface pressures of 29 cushions and a sheepskin were measured on 20 healthy volunteers. Each participant was seated in an upright posture with their back against the back of the chair, hands resting on the lap, knees bent at an angle of 90 degrees, and feet resting on the floor. Only 13 cushions had any pressure-reducing effect. Gel cushions and sheepskins appear to have no pressure-reducing effect. The category of foam includes both cushions that reduce interface pressure very well and cushions that increase interface pressure. The lowest interface pressures were measured on air cushions and on some foam cushions. PMID:10804896

Defloor, T; Grypdonck, M H

2000-04-01

143

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

144

Contact pressure measurement using silicon-based Al x Ga 1? x As semiconductor pressure sensors  

Microsoft Academic Search

Various types of pressure sensors are widely used in manufacturing, defence, medical and precision industries. Most of these sensors are based on either piezoelectric or piezoresistive mechanism for sensing applications. Piezoelectric pressure sensors are not suited for measuring static pressure mainly due to leakage of electric charges under constant pressure. Surface micromachined silicon pressure sensors, based on piezoresistive mechanism, are

Thet Naing Tun; Toh Siew Lok; Tay Cho Jui; Ramam Akkipeddi; M. Rahman

2005-01-01

145

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

NASA Astrophysics Data System (ADS)

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 together with existing P-V-T data from dynamic and static compression experiments to constrain the thermal EoS for the three phases, all of which are of fundamental importance to the dynamics of the lower mantle. The EoS for perovskite and postperovskite are well described with third-order Birch-Murnaghan isentropes, offset with a Mie-Grüneisen-Debye formulation for thermal pressure. The addition of shock data helps to distinguish among discrepant static studies of perovskite, and for postperovskite, constrain a value of K' significantly larger than 4. For the melt, we define for the first time a single EoS that fits experimental data from ambient pressure to 230 GPa; the best fit requires a fourth-order isentrope. We also provide a new EoS for Mg2SiO4 liquid, calculated in a similar manner. The Grüneisen parameters of the solid phases decrease with pressure, whereas those of the melts increase, consistent with previous shock wave experiments as well as molecular dynamics simulations. We discuss implications of our modeling for thermal expansion in the lower mantle, stabilization of ultra-low-velocity zones associated with melting at the core-mantle boundary, and crystallization of a terrestrial magma ocean.

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

2009-01-01

146

Pressure multiplier pumps offer high pressure capability  

Microsoft Academic Search

Need for pressure multiplier-type pumps was established in the 1960's. While stimulation treatments requiring pumping pressures in excess of 7500 psi were increasing, deep well drilling using the abrasive jet technique also was beginning to dictate the need for replacement or a change in the conventional reciprocating service pump. Today's pressure multiplier pump is superior to the reciprocating pump when

D. C. Cameron; F. M. Jr. Winn

1979-01-01

147

Nonlinear response of a post-tensioned concrete structure to static and dynamic internal-pressure loads  

SciTech Connect

A nonlinear finite element model of a nuclear power plant containment building was developed to determine its ultimate pressure capability under quasistatic and impulsive dynamic loads. The ADINA finite element computer code was used to develop the model because of its capability to handle concrete cracking and crushing. Results indicate that, even though excessive concrete cracking occurs, failure is ultimately caused by rupture of post-tensioning tendons.

Butler, T.A.; Bennett, J.G.

1981-01-01

148

Preventing pressure ulcers  

MedlinePLUS

Pressure ulcers are also called bedsores and pressure sores. They can form when muscles and soft tissue press ... this area to die. When this happens, a pressure ulcer may form. You have a risk of developing ...

149

High Blood Pressure  

MedlinePLUS

... light physical activity or exercise. What Is Blood Pressure? Blood pressure is the force of blood pushing ... as 120/80. Do You Have High Blood Pressure? One reason to have regular visits to the ...

150

Skin (Pressure) Sores  

MedlinePLUS

... Topic Skin dryness Next Topic Sleep problems Skin (pressure) sores A skin or pressure sore develops when the blood supply to an ... is bedridden or always in a wheelchair puts pressure on the same places much of the time. ...

151

High Blood Pressure (Hypertension)  

MedlinePLUS

... and Diabetes Heart Health for Women High Blood Pressure (Hypertension) Print and Share (PDF 109 KB) En ... Who is at risk? How is high blood pressure treated? Understanding your blood pressure: What do the ...

152

Intracranial pressure monitoring  

MedlinePLUS

ICP monitoring; CSF pressure monitoring ... There are three ways to monitor pressure in the skull (intracranial pressure). INTRAVENTRICULAR CATHETER The intraventricular catheter is the most accurate monitoring method. To insert an intraventricular catheter, a ...

153

High Blood Pressure (Hypertension)  

MedlinePLUS

... Text Size: A A A Listen High Blood Pressure (Hypertension) Nearly 1 in 3 American adults has ... your doctor prescribes it, medicine. What Is Blood Pressure? Blood pressure is the force of blood flow ...

154

Ultrasonic pressure measurement in pressure vessels  

NASA Astrophysics Data System (ADS)

Based on the reflected longitudinal wave, a new non-intrusive method for pressure measurement is proposed. The acoustoelastic theory and the thin-shell theory are introduced to develop the pressure measurement model in cylindrical pressure vessels. And a pressure measurement system is constructed to evaluate the effectiveness of the proposed method. The pressure measurement is implemented by measuring the travel-time change between two received ultrasonic sensors. The experimental results verify the feasibility and effectiveness of this new non-intrusive method. Compared with the non-intrusive pressure measurement method based on the critically refracted longitudinal wave (LCR wave), the proposed non-intrusive pressure measurement method has the advantages of higher sensitivity and higher signal-to-noise ratio.

Bi, Yao; Zhou, Hongliang; Huang, Zhiyao; Zhou, Hanhua; Yang, Xianglong

2014-12-01

155

Preventing Pressure Sores  

MedlinePLUS Videos and Cool Tools

Experts \\ Preventing Pressure Sores Topics Adult Injuries Spinal Cord Injury 101 The Basics of Spinal Cord Injury Rehabilitation Preventing Pressure Sores Transition from Hospital to Home Spasticity, Physical ...

156

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

157

Low Blood Pressure  

MedlinePLUS

... reading is 90/60 or lower, you have low blood pressure. Some people have low blood pressure all the time. They have no symptoms and ... certain medicines. Some people may have symptoms of low blood pressure when standing up too quickly. Low blood pressure ...

158

Constant-pressure Blowers  

NASA Technical Reports Server (NTRS)

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

Sorensen, E

1940-01-01

159

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

160

Neural Network Burst Pressure Prediction in Composite Overwrapped Pressure Vessels  

NASA Technical Reports Server (NTRS)

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

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

2007-01-01

161

An investigation to determine the static pressure distribution of the 0.00548 scale shuttle solid rocket booster (MSFC model number 468) during reentry in the NASA/MSFC 14 inch trisonic wind tunnel (SA28F)  

NASA Technical Reports Server (NTRS)

The results of a pressure test of a .00548 scale 146 inch Space Shuttle Solid Rocket Booster (SRB) with and without protuberances, conducted in a 14 x 14 inch trisonic wind tunnel are presented. Static pressure distributions for the SRB at reentry attitudes and flight conditions were obtained. Local longitudinal and ring pressure distributions are presented in tabulated form. Integration of the pressure data was performed. The test was conducted at Mach numbers of 0.40 to 4.45 over an angle of attack range from 60 to 185 degrees. Roll angles of 0, 45, 90 and 315 degrees were investigated. Reynolds numbers per foot varied for selected Mach numbers.

Braddock, W. F.; Streby, G. D.

1977-01-01

162

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

163

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

164

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

165

Atmospheric Pressure Indicator.  

ERIC Educational Resources Information Center

Discusses observable phenomena related to air pressure. Describes a simple, unobtrusive, semiquantitative device to monitor the changes in air pressure that are associated with altitude, using a soft-drink bottle and a balloon. (JRH)

Salzsieder, John C.

1995-01-01

166

Pressure Sensitive Paints  

NASA Technical Reports Server (NTRS)

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

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

1999-01-01

167

Radio frequency pressure transducer  

Microsoft Academic Search

A novel system is reported here for the pressure measurement at microwave and millimetre-wave frequencies. This method consists in using a radio frequency transducer based on RF resonator. Accurate determination of the pressure is expected.

M. M. Jatlaoui; P. Pons; H. Aubert

2007-01-01

168

High blood pressure - infants  

MedlinePLUS

... these numbers can be too high. Several factors affect blood pressure, including: Hormones The health of the heart and blood vessels The health of the kidneys High blood pressure in infants may be due to kidney or heart disease ...

169

Pressure surge attenuator  

DOEpatents

A pressure surge attenuation system for pipes having a fluted region opposite crushable metal foam. As adapted for nuclear reactor vessels and heads, crushable metal foam is disposed to attenuate pressure surges.

Christie, Alan M. (Swissvale, PA); Snyder, Kurt I. (Murrysville, PA)

1985-01-01

170

Dealing with Peer Pressure  

MedlinePLUS

... Main Page The Pink Locker Society Dealing With Peer Pressure KidsHealth > Kids > Feelings > My Emotions & Behaviors > Dealing ... Let's talk about how to handle it. Defining Peer Pressure Peers influence your life, even if you ...

171

High Blood Pressure  

MedlinePLUS

Blood pressure is the force of your blood pushing against the walls of your arteries. Each time your heart ... it pumps blood into the arteries. Your blood pressure is highest when your heart beats, pumping the ...

172

Blood Pressure Medicines  

MedlinePLUS

High blood pressure, also called hypertension, usually has no symptoms. But it can cause serious problems such as stroke, heart failure, ... failure. If you cannot control your high blood pressure through lifestyle changes such as losing weight and ...

173

What is Blood Pressure?  

NSDL National Science Digital Library

In this activity about heart health (on page 34 of the PDF), learners measure their own blood pressure using an electronic blood pressure monitor with a self-inflating cuff (included in cost of materials) and learn about the health effects of high blood pressure. Learners also discover how to interpret the blood pressure number (diastolic vs. systolic) and healthy ranges. This lesson guide includes background information, setup and management tips, and web resources.

Tharp, Barbara Z.; Erdmann, Deanne B.; Matyas, Marsha L.; Mcneel, Ronald L.; Moreno, Nancy P.

2009-01-01

174

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

175

The pressure multiplier revisited  

NASA Technical Reports Server (NTRS)

Pressure multipliers, which were originally intended to continuously sample an unknown pressure and increase it by a known factor, so that measurements could be conducted at low pressures with liquid-in-gas gauges, may be usefully applied to the increasing number of components available for use in molecular flow networks. An intriguing possibility involves the electric control of pressure multiplier gain by means of a piezoelectric valve.

Kendall, B. R. F.

1983-01-01

176

An electrokinetic pressure sensor  

Microsoft Academic Search

A new concept for a micro pressure sensor is demonstrated. The pressure difference between the inlet and the outlet of glass nanochannels is obtained by measuring the electrokinetically generated electric potential. To demonstrate the proposed concept, experimental investigations are performed for 100 nm wide nanochannels with sodium chloride solutions having various concentrations. The proposed pressure sensor is able to measure

Dong-Kwon Kim; Duckjong Kim; Sung Jin Kim

2008-01-01

177

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

178

High pressure ices  

PubMed Central

H2O will be more resistant to metallization than previously thought. From computational evolutionary structure searches, we find a sequence of new stable and meta-stable structures for the ground state of ice in the 1–5 TPa (10 to 50 Mbar) regime, in the static approximation. The previously proposed Pbcm structure is superseded by a Pmc21 phase at p = 930 GPa, followed by a predicted transition to a P21 crystal structure at p = 1.3 TPa. This phase, featuring higher coordination at O and H, is stable over a wide pressure range, reaching 4.8 TPa. We analyze carefully the geometrical changes in the calculated structures, especially the buckling at the H in O-H-O motifs. All structures are insulating—chemistry burns a deep and (with pressure increase) lasting hole in the density of states near the highest occupied electronic levels of what might be component metallic lattices. Metallization of ice in our calculations occurs only near 4.8 TPa, where the metallic C2/m phase becomes most stable. In this regime, zero-point energies much larger than typical enthalpy differences suggest possible melting of the H sublattice, or even the entire crystal. PMID:22207625

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

2012-01-01

179

Miniaturized pressurization system  

DOEpatents

The invention uses a fluid stored at a low pressure and provides the fluid at a high pressure. The invention allows the low pressure fluid to flow to a fluid bore of a differential pump and from the pump to a fluid pressure regulator. After flowing through the regulator the fluid is converted to a gas which is directed to a gas bore of the differential pump. By controlling the flow of gas entering and being exhausted from the gas bore, the invention provides pressure to the fluid. By setting the regulator, the high pressure fluid can be set at predetermined values. Because the invention only needs a low pressure fluid, the inventive apparatus has a low mass, and therefore would be useful in rocket propulsion systems.

Whitehead, John C. (Davis, CA); Swink, Don G. (Woodinville, WA)

1991-01-01

180

Reduction of Orifice-Induced Pressure Errors  

NASA Technical Reports Server (NTRS)

Use of porous-plug orifice reduces or eliminates errors, induced by orifice itself, in measuring static pressure on airfoil surface in wind-tunnel experiments. Piece of sintered metal press-fitted into static-pressure orifice so it matches surface contour of model. Porous material reduces orifice-induced pressure error associated with conventional orifice of same or smaller diameter. Also reduces or eliminates additional errors in pressure measurement caused by orifice imperfections. Provides more accurate measurements in regions with very thin boundary layers.

Plentovich, Elizabeth B.; Gloss, Blair B.; Eves, John W.; Stack, John P.

1987-01-01

181

PressureText: Pressure Input for Mobile Phone Text Entry  

E-print Network

PressureText: Pressure Input for Mobile Phone Text Entry Abstract Pressure sensitive buttons presses are currently necessary to record an action. We present PressureText, a text-entry technique for a pressure augmented mobile phone. In a study comparing PressureText to MultiTap, we found that despite

182

Under Pressure A 4-week Blood Pressure Program  

E-print Network

Under Pressure A 4-week Blood Pressure Program Under Pressure is a month long blood pressure program to teach you the basic facts about blood pressure, give you the tools to take charge of your health, and reward you for daily healthy habits. · Raffle prizes, healthy snacks, and free blood pressure

Reed, Christopher A.

183

Attachment Fitting for Pressure Vessel  

NASA Technical Reports Server (NTRS)

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

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

2002-01-01

184

BIOMACROMOLECULES UNDER HIGH HYDROSTATIC PRESSURE  

E-print Network

BIOMACROMOLECULES UNDER HIGH HYDROSTATIC PRESSURE A Dissertation Presented to the Faculty HIGH HYDROSTATIC PRESSURE Nozomi Ando, Ph.D. Cornell University 2009 Protein pressure denaturation denaturation studies. Recent studies imply that the mechanism of pressure denaturation is the penetration

Gruner, Sol M.

185

Types of Blood Pressure Medications  

MedlinePLUS

... Pressure Tools & Resources Stroke More Types of Blood Pressure Medications Updated:Sep 2,2014 Many medications known ... last reviewed on 08/04/2014. High Blood Pressure • Home • About High Blood Pressure (HBP) • Why HBP ...

186

Blood Pressure vs. Heart Rate  

MedlinePLUS

Blood Pressure vs. Heart Rate Updated:Sep 4,2014 Blood pressure and heart rate are not the same. Learn ... last reviewed on 08/04/2014. High Blood Pressure • Home • About High Blood Pressure (HBP) Introduction What ...

187

Living with High Blood Pressure  

MedlinePLUS

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

188

Ruby under pressure  

Microsoft Academic Search

The ruby luminescence method is widely used for pressure measurement in the diamond anvil cell and other optically transparent pressure cells. With this application in mind, we briefly review the ground-state physical properties of corundum (?-Al2O3) with some emphasis on its behavior under high pressure, survey the effects of temperature and stress on the R-line luminescence of ruby (Cr-doped corundum),

K. Syassen

2008-01-01

189

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

190

High temperature pressure gauge  

DOEpatents

A high temperature pressure gauge comprising a pressure gauge positioned in fluid communication with one end of a conduit which has a diaphragm mounted in its other end. The conduit is filled with a low melting metal alloy above the diaphragm for a portion of its length with a high temperature fluid being positioned in the remaining length of the conduit and in the pressure gauge.

Echtler, J. Paul (Pittsburgh, PA); Scandrol, Roy O. (Library, PA)

1981-01-01

191

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

192

Blood Pressure Control  

NASA Technical Reports Server (NTRS)

Engineering Development Laboratory developed a system for the cardiovascular study of weightless astronauts. This was designed to aid people with congestive heart failure and diabetes. While in space, astronauts' blood pressure rises, heart rate becomes unstable, and there are sometimes postflight lightheadedness or blackouts. The Baro-Cuff studies the resetting of blood pressure. When a silicone rubber chamber is strapped to the neck, the Baro-Cuff stimulates the carotid arteries by electronically controlled pressure application. Blood pressure controls in patients may be studied.

1986-01-01

193

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

194

Pressurized fluidized bed reactor  

DOEpatents

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

Isaksson, Juhani (Karhula, FI)

1996-01-01

195

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

196

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

197

Past Work on Isolated Airways and ASM Previous studies have examined the static pressure-area relationships of isolated airways1  

E-print Network

, and hyperresponsiveness to a range of stimuli INTRODUCTION SYSTEM OVERVIEW PROJECT END GOAL RATIONALE SPECIFIC AIMS pressure and flow Program 1 ­ Creating Desired Pressure Waveform · Labview GUI · Allows user to make · Labview GUI · Outputs pulse train and step function to stepper motor driver · Inputs and records flow

Lutchen, Kenneth

198

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

199

SAW pressure sensors  

Microsoft Academic Search

The design and performance of two types of SAW pressure sensors have been considered. SAW resonator oscillators with metal strip gratings designed for operation at 200 and 360 MHz have been used in both type devices to study the opportunity of the mechanical pressure measurement became of mechanical loading on Rayleigh surface wave propagation. Such electrical characteristics of SAW resonator

I. B. Yarovkin; Yu. N. Vlassov; A. S. Kozlov; N. S. Pashchin

1994-01-01

200

Vapor pressure of explosives  

Microsoft Academic Search

New vapor pressure data is presented for RDX, PETN, TNT, nitroglycerin, and ammonium nitrate. By comparison with the data of previous workers, it has been possible to calculate global vapor pressure expressions which are valid over a wide range of temperatures.

B. C. Dionne; D. P. Rounbehler; E. K. Achter; J. R. Hobbs; D. H. Fine

1986-01-01

201

Understanding Blood Pressure  

E-print Network

Understanding Blood Pressure · Monitorathomewithadigitalmonitor. · Useleftarmwithcorrectsizecuff. · Avoidcaffeine,alcohol,andtobacco. Steps to Follow FOR AN ACCURATE MEASUREMENT Blood pressure is the measurement of the force of blood on the walls of the arteries. Bottom number = Diastolic (force between heart beats) Top

202

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.

203

Pressure vessel flex joint  

NASA Technical Reports Server (NTRS)

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

Kahn, Jon B. (inventor)

1992-01-01

204

Combustion pressure sensor  

Microsoft Academic Search

A combustion pressure sensor is described for mounting on an internal combustion engine so as to have access to the interior of a combustion cylinder. The sensor consists of: a first diaphragm means adjacent a combustion region for deflecting as a function of the magnitude of adjacent pressure in the combustion region, and for acting as a gas tight seal

Bettman

1986-01-01

205

Too Much Pressure!  

NSDL National Science Digital Library

In this activity, students learn how engineers design faucets. Students will learn about water pressure by building a simple system to model faucets and test the relationship between pressure, area and force. This is a great outdoor activity on a warm day.

Integrated Teaching And Learning Program

206

High pressure nitriding  

SciTech Connect

The aim of the presented research project is the development of a new high pressure nitriding process, which avoids disadvantages of conventional nitriding processes and allows for new applications. Up to now, a nitriding furnace has been constructed and several investigations have been made in order to characterize the influence of pressure on the nitriding process. In this paper, connections between pressure in the range of 2 to 12 atm and the corresponding nitride layer formation for the steel grades AISI 1045, H11 and a nitriding steel are discussed. Results of the nitride layer formation are presented. For all steel grades, a growth of nitride layers with increasing pressure was obtained. Steels with passive layers, as the warm working steel H11, showed a better nitriding behavior at elevated pressure.

Jung, M.; Hoffmann, F.T.; Mayr, P. [Stiftung Inst. fuer Werkstofftechnik, Bremen (Germany); Minarski, P. [ALD Vacuum Technologies GmbH, Erlensee (Germany)

1995-12-31

207

Telemetry of intracranial pressure  

NASA Technical Reports Server (NTRS)

A completely implantable epidural pressure telemetry system designed for accurate measurement of intracranial pressure (ICP) is described. The implant device is batteryless, providing unlimited operating life. The described system uses a capacitive pressure transducer with excellent long-term stability. Once detected with the transducer and converted to a frequency with the oscillator electronics, the pressure signal is digitized. It is then telemetered without the possibility of further degradation. After detection with the small external module, the data can be retransmitted by a radio link for complete patient mobility or the energizer signal pickup module can be wired to a bedside readout unit. Continuous data are available from the system so that the dynamic ICP changes reflecting arterial blood pressure can be observed and used for diagnosis.

Fryer, T. B.; Corbin, S. D.; Silverberg, G. D.; Schmidt, E. V.; Ream, A. K.

1978-01-01

208

Passive Pressure Determination by Method of Slices  

Microsoft Academic Search

A method of slices satisfying all the conditions of statical equilibrium has been developed to deal with the problem of determination of passive earth pressure over a retaining wall in sand. A method similar to that of Morgenstern and Price, which was used to solve the stability of slopes, has been followed. The earth pressure coefficients with the proposed methodology

Jyant Kumar; Kanakapura S. Subba Rao

1997-01-01

209

Pressure Ulcer Prevention  

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 (anticipated pubicstion date - mid-2009) Purpose A pressure ulcer, also known as a pressure sore, decubitus ulcer, or bedsore, is defined as a localized injury to the skin/and or underlying tissue occurring most often over a bony prominence and caused by pressure, shear, or friction, alone or in combination. (1) Those at risk for developing pressure ulcers include the elderly and critically ill as well as persons with neurological impairments and those who suffer conditions associated with immobility. Pressure ulcers are graded or staged with a 4-point classification system denoting severity. Stage I represents the beginnings of a pressure ulcer and stage IV, the severest grade, consists of full thickness tissue loss with exposed bone, tendon, and or muscle. (1) In a 2004 survey of Canadian health care settings, Woodbury and Houghton (2) estimated that the prevalence of pressure ulcers at a stage 1 or greater in Ontario ranged between 13.1% and 53% with nonacute health care settings having the highest prevalence rate (Table 1). Executive Summary Table 1: Prevalence of Pressure Ulcers* Setting Canadian Prevalence,% (95% CI) Ontario Prevalence,Range % (n) Acute care 25 (23.8–26.3) 23.9–29.7 (3418) Nonacute care† 30 (29.3–31.4) 30.0–53.3 (1165) Community care 15 (13.4–16.8) 13.2 (91) Mixed health care‡ 22 (20.9–23.4) 13.1–25.7 (3100) All health care settings 26 (25.2–26.8) 13.1–53.3 (7774) * CI indicates confidence interval. † Nonacute care included sub-acute care, chronic care, complex continuing care, long-term care, and nursing home care. ‡ Mixed health care includes a mixture of acute, nonacute, and/or community care health care delivery settings. Pressure ulcers have a considerable economic impact on health care systems. In Australia, the cost of treating a single stage IV ulcer has been estimated to be greater than $61,000 (AUD) (approximately $54,000 CDN), (3) while in the United Kingdom the total cost of pressure ulcers has been estimated at £1.4–£2.1 billion annually or 4% of the National Health Service expenditure. (4) Because of the high physical and economic burden of pressure ulcers, this review was undertaken to determine which interventions are effective at preventing the development of pressure ulcers in an at-risk population. Review Strategy The main objective of this systematic review is to determine the effectiveness of pressure ulcer preventive interventions including Risk Assessment, Distribution Devices, Nutritional Supplementation, Repositioning, and Incontinence Management. A comprehensive literature search was completed for each of the above 5 preventive interventions. The electronic databases searched included MEDLINE, MEDLINE In-Process and Other Non-Indexed Citations, EMBASE, the Cochrane Library, and the Cumulative Index to Nursing and Allied Health Literature. As well, the bibliographic references of selected studies were searched. All studies meeting explicit inclusion and exclusion criteria for each systematic review section were retained and the quality of the body of evidence was determined using the Grading of Recommendation Assessment, Development, and Evaluation (GRADE) system. (5) Where appropriate, a meta-analysis was undertaken to determine the overall estimate of effect of the preventive intervention under review. Summary of Findings Ris

2009-01-01

210

Pressure Measurement Systems  

NASA Technical Reports Server (NTRS)

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

211

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

212

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.

Baker, Tod H. (O'Hara Township, Allegheny County, PA); Ott, Howard L. (Kiski Township, Armstrong County, PA)

1994-01-01

213

Atmospheric Pressure During Landing  

NASA Technical Reports Server (NTRS)

This figure shows the variation with time of pressure (dots) measured by the Pathfinder MET instrument during the landing period shown in image PIA00797. The two diamonds indicate the times of bridal cutting and 1st impact. The overall trend in the data is of pressure increasing with time. This is almost certainly due to the lander rolling downhill by roughly 10 m. The spacing of the horizontal dotted lines indicates the pressure change expected from 10 m changes in altitude. Bounces may also be visible in the data.

1997-01-01

214

Test Your Blood Pressure IQ  

MedlinePLUS

... IQ Updated:Feb 2,2015 Begin the quiz High Blood Pressure • Home • About High Blood Pressure (HBP) Introduction What is HBP? Understanding Blood Pressure ... BP vs. Heart Rate BP Quizzes Myths About High Blood Pressure Your Path to Healthy Blood Pressure • Why HBP ...

215

PASSIVE EARTH PRESSURE DISTRIBUTION UNDER SEISMIC CONDITION  

Microsoft Academic Search

Knowledge of passive resistance and its distribution behind the rigid retaining walls under both static and dynamic conditions are important for designing retaining walls, anchors, foundations etc. In this paper, a method of horizontal slices has been suggested for obtaining seismic passive earth pressure distribution by considering seismic forces in a pseudo-static manner. Only planar rupture surfaces have been considered

Deepankar Choudhury; K. S. Subba Rao; Sanghamitro Ghosh

216

High Temperature Dynamic Pressure Measurements Using Silicon Carbide Pressure Sensors  

NASA Technical Reports Server (NTRS)

Un-cooled, MEMS-based silicon carbide (SiC) static pressure sensors were used for the first time to measure pressure perturbations at temperatures as high as 600 C during laboratory characterization, and subsequently evaluated in a combustor rig operated under various engine conditions to extract the frequencies that are associated with thermoacoustic instabilities. One SiC sensor was placed directly in the flow stream of the combustor rig while a benchmark commercial water-cooled piezoceramic dynamic pressure transducer was co-located axially but kept some distance away from the hot flow stream. In the combustor rig test, the SiC sensor detected thermoacoustic instabilities across a range of engine operating conditions, amplitude magnitude as low as 0.5 psi at 585 C, in good agreement with the benchmark piezoceramic sensor. The SiC sensor experienced low signal to noise ratio at higher temperature, primarily due to the fact that it was a static sensor with low sensitivity.

Okojie, Robert S.; Meredith, Roger D.; Chang, Clarence T.; Savrun, Ender

2014-01-01

217

Blood Pressure Checker  

NASA Technical Reports Server (NTRS)

An estimated 30 million people in the United States have high blood pressure, or hypertension. But a great many of them are unaware of it because hypertension, in its initial stages, displays no symptoms. Thus, the simply-operated blood pressure checking devices now widely located in public places are useful health aids. The one pictured above, called -Medimax 30, is a direct spinoff from NASA technology developed to monitor astronauts in space. For manned space flights, NASA wanted a compact, highly-reliable, extremely accurate method of checking astronauts' blood pressure without the need for a physician's interpretive skill. NASA's Johnson Space Center and Technology, Inc., a contractor, developed an electronic sound processor that automatically analyzes blood flow sounds to get both systolic (contracting arteries) and diastolic (expanding arteries) blood pressure measurements. NASA granted a patent license for this technology to Advanced Life Sciences, Inc., New York City, manufacturers of Medimax 30.

1979-01-01

218

MEMS Pressure Sensor Operation  

NSDL National Science Digital Library

This animation, created by Southwest Center for Microsystems Education (SCME), allows viewers to observe the operation of a micropressure sensor and the packaging of a micropressure sensor array. The animation illustrates "the sensing circuit for the pressure sensor is a Wheatstone Bridge configuration with two variable resistors (strain gauges) that change in resistance with a change in pressure. The sensing circuit is mounted on top of a fixed pressure chamber referred to as the reference chamber. When the pressures above and below the sensing circuit are different, the membrane flexes causing a change in bridge resistance." A supporting learning module, Wheatstone Bridge, can be downloaded from the SCME website under Educational Materials.

2014-07-30

219

Increased intracranial pressure  

MedlinePLUS

... is a rise in the pressure inside the skull that can result from or cause brain injury. ... Infants: Drowsiness Separated sutures on the skull Bulging of the ... and adults: Behavior changes Decreased consciousness Headache ...

220

High pressure counterflow CHF.  

E-print Network

This is a report of the experimental results of a program in countercurrent flow critical heat flux. These experiments were performed with Freon 113 at 200 psia in order to model a high pressure water system. An internally ...

Walkush, Joseph Patrick

1975-01-01

221

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

222

Downhole pressure sensor  

NASA Technical Reports Server (NTRS)

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

Berdahl, C. M.

1980-01-01

223

Trielectrode capacitive pressure transducer  

NASA Technical Reports Server (NTRS)

Capacitive transducer eliminates adverse effects of temperature and humidity; it is especially suited for measuring pressure changes in high-temperature environment. Transducer basically is three-electrode device.

Coon, G. W.

1975-01-01

224

Capacitance pressure sensor  

DOEpatents

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

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

2000-01-01

225

On Time Performance Pressure  

NASA Technical Reports Server (NTRS)

Within many operations, the pressures for on-time performance are high. Each month, on-time statistics are reported to the Department of Transportation and made public. There is a natural tendency for employees under pressure to do their best to meet these objectives. As a result, pressure to get the job done within the allotted time may cause personnel to deviate from procedures and policies. Additionally, inadequate or unavailable resources may drive employees to work around standard processes that are seen as barriers. However, bypassing practices to enable on-time performance may affect more than the statistics. ASRS reports often highlight on-time performance pressures which may result in impact across all workgroups in an attempt to achieve on-time performance. Reporters often provide in-depth insights into their experiences which can be used by industry to identify and focus on the implementation of systemic fixes.

Connell, Linda; Wichner, David; Jakey, Abegael

2013-01-01

226

Nonlinear optomechanical pressure  

NASA Astrophysics Data System (ADS)

A transparent material exhibits ultrafast optical nonlinearity and is subject to optical pressure if irradiated by a laser beam. However, the effect of nonlinearity on optical pressure is often overlooked, even if a nonlinear optical pressure may be potentially employed in many applications, such as optical manipulation, biophysics, cavity optomechanics, quantum optics, and optical tractors, and is relevant in fundamental problems such as the Abraham-Minkoswky dilemma or the Casimir effect. Here, we show that an ultrafast nonlinear polarization gives indeed a contribution to the optical pressure that also is negative in certain spectral ranges; the theoretical analysis is confirmed by first-principles simulations. An order-of-magnitude estimate shows that the effect can be observable by measuring the deflection of a membrane made by graphene.

Conti, Claudio; Boyd, Robert

2014-03-01

227

Radial pressure flange seal  

DOEpatents

This invention provides an all metal seal for vacuum or pressure vessels or systems. This invention does not use gaskets. The invention uses a flange which fits into a matching groove. Fluid pressure is applied in a chamber in the flange causing at least one of the flange walls to radially press against a side of the groove creating the seal between the flange wall and the groove side. 5 figs.

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

1989-01-24

228

Radial pressure flange seal  

DOEpatents

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

Batzer, Thomas H. (Livermore, CA); Call, Wayne R. (Tracy, CA)

1989-01-01

229

Micturitional urethral pressure profilometry.  

PubMed

The technique of micturitional urethral pressure profilometry using a trilumen catheter provides a method of assessing the dynamic behavior of the lower urinary tract during voiding. This method of evaluation is simple to perform, highly reproducible, accurate, and clinically useful not only in diagnosing the presence of outlet obstruction, but also in identifying its location and assessing its severity. The rationale for the use of this technique, the interpretation of the results, and various pressure profile configurations are discussed. PMID:8659026

Sullivan, M P; Comiter, C V; Yalla, S V

1996-05-01

230

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. PMID:23150558

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

2012-01-01

231

Blood pressure monitors for home  

MedlinePLUS

... type of blood pressure monitor for home use. DIGITAL BLOOD PRESSURE MONITORS A digital device will also have a cuff that wraps ... on its own. The screen will show a digital readout of your systolic and diastolic blood pressure. ...

232

High Blood Pressure Fact Sheet  

MedlinePLUS

... this? Submit What's this? Submit Button Related CDC Web Sites Heart Disease Stroke High Blood Pressure Salt ... blood pressure tests and other chronic disease screening. Web Sites with More Information About High Blood Pressure ...

233

Taking Care of Pressure Sores  

MedlinePLUS

... Tract Infections: Indwelling (Foley) Catheter Taking Care of Pressure Sores [Download this pamphlet: "Taking Care of Pressure ... may not show up right away. Stages of pressure sores and how to care for them: STAGE ...

234

What Causes High Blood Pressure?  

MedlinePLUS

... the NHLBI on Twitter. What Causes High Blood Pressure? Blood pressure tends to rise with age, unless ... This Content: Next >> Featured Video Myth-busting blood pressure - a hypertension Google+ hangout in honor of World ...

235

Automated high pressure cell for pressure jump x-ray diffraction  

SciTech Connect

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

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

2010-06-15

236

Questions and Answers about High Blood Pressure  

MedlinePLUS

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

237

Passive blast pressure sensor  

SciTech Connect

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

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

2013-03-19

238

Wall Pressure Spectral Model Including the Adverse Pressure Gradient Effects  

E-print Network

Wall Pressure Spectral Model Including the Adverse Pressure Gradient Effects Yannick Rozenberg 1 Sherbrooke, Sherbrooke, QC, J1K2R1, Canada An empirical model to predict the wall-pressure fluctuations spectra beneath ad- verse pressure gradient flows is presented. It is based on Goody's model which already

Paris-Sud XI, Université de

239

Gas-static facility for physicochemical studies at temperatures up to 1200-1400 C and pressures up to 1.7 GPa  

NASA Astrophysics Data System (ADS)

A high-hydrostatic-pressure facility has been developed and is now operating at the Institute of Experimental Mineralogy of the Soviet Academy of Sciences. The facility is equipped with internal heating and is capable of prolonged operation at temperatures up to 1200-1400 C and pressures up to 1.7 GPa. The system is designed to investigate the phase equilibria and reaction kinetics of minerals (as well as to synthesize these minerals) and to determine the physical and thermodynamic properties of substances in a solid-melt-fluid system corresponding to conditions in the earth's core and partly to conditions in the upper mantle. Diagrams of the high-pressure vessel and of the value unit are presented, and example results are discussed.

Zharikov, V. A.; Ivanov, I. P.; Kapustin, N. V.; Likhoidov, G. G.

240

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

241

Pressure suppression containment system  

DOEpatents

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

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

1994-03-15

242

A Microwave Pressure Sounder  

NASA Technical Reports Server (NTRS)

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

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

1978-01-01

243

Magnetostrictive Pressure Regulating System  

NASA Technical Reports Server (NTRS)

A magnetostrictive pressure regulating system includes a magnetostrictive valve that incorporates a magnetostrictive actuator with at least one current-carrying coil disposed thereabout. A pressure force sensor, in fluid communication with the fluid exiting the valve, includes (i) a magnetostrictive material, (ii) a magnetic field generator in proximity to the magnetostrictive material for inducing a magnetic field in and surrounding the magnetostrictive material wherein lines of magnetic flux passing through the magnetostrictive material are defined, and (iii) a sensor positioned adjacent to the magnetostrictive material and in the magnetic field for measuring changes in at least one of flux angle and flux density when the magnetostrictive material experiences an applied force that is aligned with the lines of magnetic flux. The pressure of the fluid exiting the valve causes the applied force. A controller coupled to the sensor and to the current-carrying coil adjusts a current supplied to the current-carrying coil based on the changes so-measured.

Richard, James A. (Inventor); Pickens, Herman L. (Inventor)

2013-01-01

244

Pressure Sensor Process Activity  

NSDL National Science Digital Library

The Southwest Center for Microsystems Education is a Regional Advanced Technology Education Center funded in part by the National Science Foundation. This page provides instructor and participant guides for the Pressure Sensor Process Activity and Kit. An order form is provided to order this kit complete with several small boxes with each box containing a "chip" that represents the outcome of one step of a ten step pressure sensor process. Participants are asked to study each chip and then arrange the ten chips in the correct process order. Visitors are encouraged to create an account and login in order to access the full set of resources.

2011-10-11

245

Blood Pressure Control  

NASA Technical Reports Server (NTRS)

Engineering Development Lab., Inc.'s E-2000 Neck Baro Reflex System was developed for cardiovascular studies of astronauts. It is regularly used on Space Shuttle Missions, and a parallel version has been developed as a research tool to facilitate studies of blood pressure reflex controls in patients with congestive heart failure, diabetes, etc. An advanced version, the PPC-1000, was developed in 1991, and the technology has been refined substantially. The PPC provides an accurate means of generating pressure for a broad array of laboratory applications. An improved version, the E2010 Barosystem, is anticipated.

1992-01-01

246

Saltstone Osmotic Pressure  

SciTech Connect

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

Nichols, Ralph L.; Dixon, Kenneth L.

2013-09-23

247

Submarine Coaxial Cable Pressure Characteristics  

Microsoft Academic Search

In equalization design of submarine coaxial cable system, the cable attenuation deviation due to pressure in deep sea bottom has significant weight. This paper treats the submarine coaxial cable characteristics pressure dependency. By using an artificial ocean test facility, 1.7 inch submarine coaxial cable attenuation, phase, capacitance and insulator core diameter were studied and their pressure coefficients under a pressure

K. Aida; M. Aiki

1978-01-01

248

What Is High Blood Pressure?  

MedlinePLUS

What is High Blood Pressure? Updated:Sep 4,2014 High blood pressure, also known as HBP or hypertension, is a widely misunderstood medical ... content was last reviewed on 08/04/2014. High Blood Pressure • Home • About High Blood Pressure (HBP) Introduction What ...

249

Radiation Pressure Against Perfect Reflectors  

Microsoft Academic Search

The concept of radiation pressure exerted against a reflecting surface by electromagnetic waves and by sound waves in gases is a familiar one. The absence of radiation pressure for sound waves in a ``linear medium'' is becoming well known. The equations are somewhat different for the radiation pressure for these two cases where the radiation pressure is not zero. The

J. Elmer Rhodes

1953-01-01

250

High Blood Pressure and Women  

MedlinePLUS

High Blood Pressure and Women Updated:Aug 13,2014 Many people mistakenly believe that high blood pressure, also called HBP or ... last reviewed on 08/04/14. High Blood Pressure • Home • About High Blood Pressure (HBP) • Why HBP ...

251

Dynamic Pressure Probes Developed for Supersonic Flow-Field Measurements  

NASA Technical Reports Server (NTRS)

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

Porro, A. Robert

2001-01-01

252

Pluto's Increasing Atmospheric Pressure  

NASA Astrophysics Data System (ADS)

In 2007, the occultation of a V=13.2 magnitude star was successfully observed from Mt. John Observatory, Mt. Canopus Observatory and our 14-inch Meade portable system in Musselroe Bay, New Zealand. We simultaneously fit an isothermal model atmosphere (Eliot and Young, 1992) to the main drop and recovery of the observed occultation light curves to derive global atmospheric parameters and a geometric solution. The data is well fit by a spherical atmospheric model with no need to fit for an oblate profile. The isothermal atmospheric solution gives a temperature of 112 ± 1 K and a pressure of 2.4 ± 0.1 microbar at a radius of 1275 km. This is an increase in temperature of 8 K and a 28% increase in pressure at our reference radius over 13 months (the previous stellar occultation was in June 2006, Young et al. 2008) with no significant change in half-light radius. Due to the increase in temperature and hence scale height, we expect the surface pressure did not increase as dramatically. The sensitivity of atmospheric pressure to changes in isothermal temperature will be discussed. This work was supported by NASA planetary astronomy grant NNG05GF05G and NSF major research instrumentation grant AST0321338.

Olkin, Catherine B.; Young, L.; Young, E.; Buie, M.; French, R.; Howell, R.; Regester, J.; Ruhland, C.

2009-09-01

253

The Blood Pressure \\  

Microsoft Academic Search

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

Cornel Pater

2005-01-01

254

Pressurized lunar rover  

Microsoft Academic Search

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

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

1992-01-01

255

Reactor pressure vessel nozzle  

DOEpatents

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

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

1994-01-01

256

Pressure vessel integrity 1991  

SciTech Connect

This volume contains papers relating to the structural integrity assessment of pressure vessels and piping, with special emphasis on nuclear industry applications. The papers were prepared for technical sessions developed under the sponsorship of the ASME Pressure Vessels and Piping Division Committees for Codes and Standards, Computer Technology, Design and Analysis, and Materials Fabrication. They were presented at the 1991 Pressure Vessels and Piping Division Conference in San Diego, California, June 23-27. The primary objective of the sponsoring organization is to provide a forum for the dissemination and discussion of information on development and application of technology for the structural integrity assessment of pressure vessels and piping. This publication includes contributions from authors from Australia, France, Japan, Sweden, Switzerland, the United Kingdom, and the United States. The papers here are organized in six sections, each with a particular emphasis as indicated in the following section titles: Fracture Technology Status and Application Experience; Crack Initiation, Propagation and Arrest; Ductile Tearing; Constraint, Stress State, and Local-Brittle-Zones Effects; Computational Techniques for Fracture and Corrosion Fatigue; and Codes and Standards for Fatigue, Fracture and Erosion/Corrosion.

Bhandari, S. (Framatome (FR)); Doney, R.O.; McDonald, M.S. (ABB Combustion Engineering Nuclear Power (US)); Jones, D.P.; Wilson, W.K. (Westinghouse Bettis Atomic Power Laboratory (US)); Pennell, W.E. (Oak Ridge National Laboratory (US))

1991-01-01

257

Pressure in Fluids  

NSDL National Science Digital Library

This simple resource, created by Porter W. Johnson of Illinois Institute of Technology, features activities for upper level high school students about the properties of fluids under a variety of circumstances. Students will also understand the importance of pressure in fluid behavior and how it pertains to everyday life. The page includes objectives, needed materials, strategy, performance assessments and conclusions.

2008-02-07

258

INTERMITTENT POSITIVE PRESSURE BREATHING  

EPA Science Inventory

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

259

Negative pressure wound therapy  

Microsoft Academic Search

iabetic foot disease is a major global burden. Foot ulcers frequently develop complications and become chronic, representing a considerable challenge as these are typically very difficult to treat. New therapies are needed to address these wounds and there is an increasing focus on negative pressure wound therapy (NPWT). This technique has been shown to accelerate wound healing and although its

Michael Kirby

2007-01-01

260

Negative pressure wound therapy  

Microsoft Academic Search

D iabetic foot disease is a major global burden. Foot ulcers frequently develop complications and become chronic, representing a considerable challenge as these are typically very difficult to treat. New therapies are needed to address these wounds and there is an increasing focus on negative pressure wound therapy (NPWT). This technique has been shown to accelerate wound healing and although

MICHAEL KIRBY

2010-01-01

261

Reactor pressure vessel nozzle  

DOEpatents

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

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

1994-10-04

262

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

263

Peer Pressure and Partnerships  

Microsoft Academic Search

Partnerships and profit sharing are often claimed to motivate workers by giving them a share of the pie. But in organizations of any significant size, the free-rider effects would seem to choke off any motivational forces. This analysis explores how peer pressure operates and how factors such as profit sharing, shame, guilt, norms, mutual monitoring, and empathy interact to create

Eugene Kandel; Edward P. Lazear

1992-01-01

264

Negative Pressure Wound Therapy  

PubMed Central

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

2006-01-01

265

Pressure as a Source of Gravity  

E-print Network

The active mass density in Einstein's theory of gravitation in the analog of Poisson's equation in a local inertial system is proportional to $\\rho+3p/c^2$. Here $\\rho$ is the density of energy and $p$ its pressure for a perfect fluid. By using exact solutions of Einstein's field equations in the static case we study whether the pressure term contributes towards the mass.

J. Ehlers; I. Ozsvath; E. L. Schucking; Y. Shang

2005-10-08

266

Pressure natriuresis and the renal control of arterial blood pressure.  

PubMed

The regulation of extracellular fluid volume by renal sodium excretion lies at the centre of blood pressure homeostasis. Renal perfusion pressure can directly regulate sodium reabsorption in the proximal tubule. This acute pressure natriuresis response is a uniquely powerful means of stabilizing long-term blood pressure around a set point. By logical extension, deviation from the set point can only be sustained if the pressure natriuresis mechanism is impaired, suggesting that hypertension is caused or sustained by a defect in the relationship between renal perfusion pressure and sodium excretion. Here we describe the role of pressure natriuresis in blood pressure control and outline the cascade of biophysical and paracrine events in the renal medulla that integrate the vascular and tubular response to altered perfusion pressure. Pressure natriuresis is impaired in hypertension and mechanistic insight into dysfunction comes from genetic analysis of blood pressure disorders. Transplantation studies in rats show that blood pressure is determined by the genotype of the kidney and Mendelian hypertension indicates that the distal nephron influences the overall natriuretic efficiency. These approaches and the outcomes of genome-wide-association studies broaden our view of blood pressure control, suggesting that renal sympathetic nerve activity and local inflammation can impair pressure natriuresis to cause hypertension. Understanding how these systems interact is necessary to tackle the global burden of hypertension. PMID:25107929

Ivy, Jessica R; Bailey, Matthew A

2014-09-15

267

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

268

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

269

Quantification of pressure relief using interface pressure and tissue perfusion in alternating pressure air mattresses  

Microsoft Academic Search

Rithalia SVS, Gonsalkorale M. Quantification of pressure relief using interface pressure and tissue perfusion in alternating pressure air mattresses. Arch Phys Med Rehabil 2000;81:1364-9. Objective: To examine whether the interface pressure (IP) relief provided by alternating pressure air mattresses (APAMs) is matched with maintenance of tissue perfusion over the points of contact by measuring transcutaneous oxygen and carbon dioxide (tcPO2,

Shyam V. S. Rithalia; Mahendra Gonsalkorale

2000-01-01

270

The Measurement of Pressure Through Tubes in Pressure Distribution Tests  

NASA Technical Reports Server (NTRS)

The tests described in this report were made to determine the error caused by using small tubes to connect orifices on the surface of aircraft to central pressure capsules in making pressure distribution tests. Aluminum tubes of 3/16-inch inside diameter were used to determine this error. Lengths from 20 feet to 226 feet and pressures whose maxima varied from 2 inches to 140 inches of water were used. Single-pressure impulses for which the time of rise of pressure from zero to a maximum varied from 0.25 second to 3 seconds were investigated. The results show that the pressure recorded at the capsule on the far end of the tube lags behind the pressure at the orifice end and experiences also a change in magnitude. For the values used in these tests the time lag and pressure change vary principally with the time of rise of pressure from zero to a maximum and the tube length. Curves are constructed showing the time lag and pressure change. Empirical formulas are also given for computing the time lag. Analysis of pressure distribution tests made on airplanes in flight shows that the recorded pressures are slightly higher than the pressures at the orifice and that the time lag is negligible. The apparent increase in pressure is usually within the experimental error, but in the case of the modern pursuit type of airplane the pressure increase may be 5 per cent. For pressure-distribution tests on airships the analysis shows that the time lag and pressure change may be neglected.

Hemke, Paul E

1928-01-01

271

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

272

Microscale pressure fluctuations in a mature deciduous forest  

Microsoft Academic Search

Static pressure fluctuations in the microscale range were measured in a mature deciduous forest. Pressure measurements were taken at the ground and above the canopy, and mean profile data of windspeed were collected from above the canopy to near the forest floor. Time series, spectra, and cross-correlations were calculated under different canopy conditions, and relationships between surface pressure fluctuations and

J. T. Sigmon; K. R. Knoerr; E. J. Shaughnessy

1983-01-01

273

33 CFR 183.586 - Pressure impulse test.  

Code of Federal Regulations, 2014 CFR

...2014-07-01 2014-07-01 false Pressure impulse test. 183.586 Section... Fuel Systems Tests § 183.586 Pressure impulse test. A fuel tank is tested...following order: (a) Perform the static pressure test under § 183.580....

2014-07-01

274

Implanted Blood-Pressure-Measuring Device  

NASA Technical Reports Server (NTRS)

Arterial pressure compared with ambient bodily-fluid pressure. Implanted apparatus, capable of measuring blood pressure of patient, includes differential-pressure transducer connected to pressure sensor positioned in major artery. Electrical signal is function of differential pressure between blood-pressure sensor and reference-pressure sensor transmitted through skin of patient to recorder or indicator.

Fischell, Robert E.

1988-01-01

275

Pressure suppression system  

DOEpatents

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

Gluntz, Douglas M. (San Jose, CA)

1994-01-01

276

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

277

High pressure furnace  

DOEpatents

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

Morris, Donald E. (Kensington, CA)

1993-01-01

278

Seat pressure distribution.  

PubMed

The field of seat pressure distribution has grown more and more important in the last five decades. Compared to the early phases of development, when only a description in principle was the goal, the quantitative differentiation of force induction and furthermore the evaluation of different supporting systems by these methods have gained importance over the years. Recent developments in the ergonomic field assign increasing importance to the seat pressure distribution measurement, because now the effects of the seat design on the human body are not viewed monolinearly, but the interaction of the body and the seat is also taken into consideration in order to assess functional consequences for the person using the seat and to give guidelines for producing adequate products for the human bodysphere. PMID:9439054

Jürgens, H W

1997-12-01

279

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

280

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

281

High pressure induced superconductivity  

Microsoft Academic Search

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

K. Amaya; K. Shimizu

2003-01-01

282

Pressure Garment Subsystem Roadmap  

NASA Technical Reports Server (NTRS)

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 document that guides the team priorities. The roadmap also communicates technical reactions to changes in project priorities and funding. This paper presents the roadmap and discusses specific roadmap elements in detail as representative examples to provide insight into the meaning and use of the roadmap.

Ross, Amy J.

2010-01-01

283

High pressure gas target  

NASA Astrophysics Data System (ADS)

Compact, high pressure, high current gas target features all metal construction and semi-automatic window assembly change. The unique aspect of this target is the domed-shaped window. The Havar alloy window is electron beam welded to a metal ring, thus forming one, interchangeable assembly. The window assembly is sealed by knife-edges locked by a pneumatic toggle allowing a quick, in situ window change.

Gelbart, W.; Johnson, R. R.; Abeysekera, B.

2012-12-01

284

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

285

Columbus pressurized module verification  

NASA Technical Reports Server (NTRS)

The baseline verification approach of the COLUMBUS Pressurized Module was defined during the A and B1 project phases. Peculiarities of the verification program are the testing requirements derived from the permanent manned presence in space. The model philosophy and the test program have been developed in line with the overall verification concept. Such critical areas as meteoroid protections, heat pipe radiators and module seals are identified and tested. Verification problem areas are identified and recommendations for the next development are proposed.

Messidoro, Piero; Comandatore, Emanuele

1986-01-01

286

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

287

46 CFR 197.462 - Pressure vessels and pressure piping.  

Code of Federal Regulations, 2011 CFR

...using the breathing mixture normally used in service. (3) Equivalent nondestructive testing may be conducted in lieu of pressure testing. Proposals to use nondestructive testing in lieu of pressure testing shall be submitted to the...

2011-10-01

288

46 CFR 197.462 - Pressure vessels and pressure piping.  

Code of Federal Regulations, 2014 CFR

...using the breathing mixture normally used in service. (3) Equivalent nondestructive testing may be conducted in lieu of pressure testing. Proposals to use nondestructive testing in lieu of pressure testing shall be submitted to the...

2014-10-01

289

46 CFR 197.462 - Pressure vessels and pressure piping.  

Code of Federal Regulations, 2012 CFR

...using the breathing mixture normally used in service. (3) Equivalent nondestructive testing may be conducted in lieu of pressure testing. Proposals to use nondestructive testing in lieu of pressure testing shall be submitted to the...

2012-10-01

290

46 CFR 197.462 - Pressure vessels and pressure piping.  

Code of Federal Regulations, 2013 CFR

...using the breathing mixture normally used in service. (3) Equivalent nondestructive testing may be conducted in lieu of pressure testing. Proposals to use nondestructive testing in lieu of pressure testing shall be submitted to the...

2013-10-01

291

A flexible pressure monitoring system for pressure ulcer prevention  

E-print Network

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, ...

Yip, Marcus

292

Wideband piezoelectric pressure transducer  

NASA Astrophysics Data System (ADS)

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

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

1986-02-01

293

Pressure-Application Device for Testing Pressure Sensors  

NASA Technical Reports Server (NTRS)

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

2002-01-01

294

Hybrid Inflatable Pressure Vessel  

NASA Technical Reports Server (NTRS)

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

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

2004-01-01

295

Capacitance Level Gauge for Pressurizers of Pressurized Water Reactor Plants  

Microsoft Academic Search

The pressure of a pressurized water nuclear power plant is maintained by heating water to saturation temperature in a vessel partially filled with water. The water level in this vessel, the pressurizer, must be monitored for safe plant operation. This paper describes the application of a well-known principle of liquid level measurement to this problem. The unusual operating conditions made

William Gernert

1958-01-01

296

Air Pressure, Height and Temperature  

NSDL National Science Digital Library

This undergraduate meteorology tutorial uses the balancing of gravity/centrifugal forces and the vertical pressure gradient with the ideal gas law to explain how pressure, temperature, and height are related in the atmosphere.

Nielsen-Gammon, John

1996-01-01

297

High Blood Pressure in Pregnancy  

MedlinePLUS

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

298

Economics of Steam Pressure Reduction  

E-print Network

Economics of Steam Pressure Reduction is a technical paper that addresses the operating and economic advantages associated with the program to lower the steam operating pressure. Evaluation of a testing program will be discussed. The paper...

Sylva, D. M.

299

Controlling your high blood pressure  

MedlinePLUS

Hypertension is another term used to describe high blood pressure. High blood pressure can lead to stroke, heart attack, heart failure, kidney disease, and early death. You are more likely to have high ...

300

Pregnancy and High Blood Pressure  

MedlinePLUS Videos and Cool Tools

... right-hand corner of the player. Pregnancy and High Blood Pressure HealthDay January 29, 2015 Related MedlinePlus Page High Blood Pressure in Pregnancy Transcript Does keeping tight control of ...

301

Vapor Pressure measurements for dichlorosilane  

E-print Network

trichlorosilane and silicon tetrachloride, or other chemicals which are not in the silane family. Accurate information about the vapor pressure is necessary in the production of these mixtures. Measurements reported previously for the vapor pressure of pure...

Morris, Tony Knimbula

2012-06-07

302

Blood Pressure Drugs and AMD  

MedlinePLUS

... Eye Health News Consumer Alerts Research News: Blood Pressure Drugs and AMD Tweet Eye Health Lifestyle Topics ... found an association between AMD and high blood pressure, but this has been inconsistent. Vision Simulator: Age- ...

303

Stroke and High Blood Pressure  

MedlinePLUS

Stroke and High Blood Pressure Updated:Jan 6,2015 Stroke is a leading cause of death and severe, long-term disability. Since managing high blood pressure, also called HBP or hypertension, is the most ...

304

Medications for High Blood Pressure  

MedlinePLUS

... all parts of the body in vessels called arteries. Blood pressure is the force of the blood pushing ... the body and against the walls of the arteries. The higher the blood pressure, the greater the risk of stroke, heart ...

305

What's with All the Pressure?  

NSDL National Science Digital Library

Students learn how to take blood pressure by observing a teacher demonstration and then practicing on fellow classmates in small groups. Once the hands-on component of this activity is completed, the class brainstorms and discusses how blood pressure might affect a person's health. This activity acts as hook for the second lesson in this unit, in which blood pressure is presented in detail, as well as how variances in blood pressure can affect a person's cardiovascular system.

Vu Bioengineering Ret Program

306

Continuous automated pressure ulcer monitoring.  

PubMed

In the spring of 2002, the nurses working in a 300-bed Midwest care center embarked on a mission to decrease patient suffering from skin breakdown and pressure ulcers. A continuous automated pressure ulcer monitoring system was developed to improve decision making and identify educational needs. As a result, the nurses have changed the skin culture of the facility and positively affected the rate of hospital-acquired pressure ulcers and non-pressure-related breakdown. PMID:17538267

Dobbs, Nancy Ann; Spanbauer, Pam; Datz, David

2007-01-01

307

A temperature and pressure controlled calibration system for pressure sensors  

NASA Technical Reports Server (NTRS)

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

Chapman, John J.; Kahng, Seun K.

1989-01-01

308

Intracranial pressure monitoring system with pneumatic capsule sensor  

NASA Astrophysics Data System (ADS)

In the paper, a computer system for measurement, visualization and analysis of intracranial pressure (ICP), medium arterial pressure and cerebral perfusion pressure in one, two, three or four patients simultaneously has been presented. A structure of pneumatic compensatory sensor for intracranial pressure, and a stand for static properties of the sensors testing has been discussed. Conclusions resulting from the period of using the monitoring system with ICP pneumatic sensors have been formulated.

Juniewicz, Henryk M.; Werszko, Miroslaw

1995-06-01

309

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

310

7, 1183911894, 2007 Vapor pressure  

E-print Network

ACPD 7, 11839­11894, 2007 Vapor pressure prediction J. F. Pankow and W. E. Asher Title Page pressures and enthalpies of vaporization of multifunctional organic compounds J. F. Pankow 1 and W. E. Asher (pankow@ebs.ogi.edu) 11839 #12;ACPD 7, 11839­11894, 2007 Vapor pressure prediction J. F. Pankow and W. E

Paris-Sud XI, Université de

311

Vapor Pressure Formulation for Ice  

Microsoft Academic Search

A new formulation is presented for the vapor pressure of ice from the triple point to —100 °C based on thermodynamic calculations. Use is made of the definitive experimental value of the vapor pressure of water at its triple point recently obtained by Guildner, Johnson, and Jones. A table is given of the vapor pressure as a function of temperature

Arnold Wexler

1977-01-01

312

Fiber-optic pressure sensor  

SciTech Connect

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

313

ORIGINAL ARTICLE Blood pressure, antihypertensive  

E-print Network

; antihypertensive; epidemiological; management; Spain Introduction High blood pressure (BP) is strongly associatedORIGINAL ARTICLE Blood pressure, antihypertensive treatment and factors associated with good blood subjects, yet not many of these are specific to Spain. To assess the degree of blood pressure (BP) control

Cai, Long

314

Reliability of passive earth pressure  

Microsoft Academic Search

Passive earth pressure calculations in geotechnical analysis are usually performed with the aid of the Rankine or Coulomb theories of earth pressure based on uniform soil properties. These traditional earth pressure theories assume that the soil is uniform. The fact that soils are spatially variable leads to two potential problems in design: do sampled soil properties adequately reflect the effective

D. V. Griffiths; Gordon A. Fenton; Heidi R. Ziemann

2008-01-01

315

High Blood Pressure in Pregnancy  

MedlinePLUS

What Is High Blood Pressure? Blood pressure is the amount of force exerted by the blood against the walls of the arteries. A person's blood ... disease. What Are the Effects of High Blood Pressure in Pregnancy? Although many pregnant women with high ...

316

Blood Pressure Medicine: Special Instructions  

E-print Network

Blood Pressure Medicine: Special Instructions: U.S. DEPARTMENT OF HEALTH AND HUMAN SERVICES National Institutes of Health National Heart, Lung, and Blood Institute · What is my blood pressure reading in numbers? · What is my goal blood pressure? · Is there a healthy eating plan that I should follow to help

Bandettini, Peter A.

317

Applications of the Radiation Pressure  

E-print Network

Applications of the Radiation Pressure Prepared: Volodymyr Borshch Course: LC Optics and Photonics in 1871 · The predicted value of the light pressure 4.7 x 10-6 Pa · And also Adolfo Bartoli in 1876 #12 and 10-6 torr (maximum effect 10-2 torr) · DOES NOT demonstrate radiation pressure #12;8 Nichols

Palffy-Muhoray, Peter

318

Abnormal pressure in hydrocarbon environments  

USGS Publications Warehouse

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

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

1998-01-01

319

Hydrostatic pressure mimics gravitational pressure in characean cells  

NASA Technical Reports Server (NTRS)

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

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

1992-01-01

320

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

321

Unibody Composite Pressurized Structure  

NASA Technical Reports Server (NTRS)

An integrated, generic unibody composite pressurized structure (UCPS) combined with a positive expulsion device (PED), consisting of an elastomeric bladder for monopropellant hydrazine, has been quasi-standardized for spacecraft use. The combination functions as an all-composite, non-metallic, propellant tank with bladder. The integrated UCPS combines several previous innovations - specifically, the linerless, all-composite cryogenic tank technology; all-composite boss; resin formulation; and integrated stringer system. The innovation combines the UCPS with an integrated propellant management device (PMD), the PED or bladder, to create an entirely unique system for in-space use. The UCPS is a pressure vessel that incorporates skirts, stringers, and other structures so that it is both an in-space hydrazine tank, and also a structural support system for a spacecraft in a single, all-composite unit. This innovation builds on the progress in the development of a previous SBIR (Small Business Innovation Research) Phase I with Glenn Research Center and an SBIR III with Johnson Space Center that included the fabrication of two 42-in. (˜107-cm) diameter all-composite cryogenic (LOX and liquid methane) UCPS test tanks for a lunar lander. This Phase II provides hydra zine compatibility testing of the elastomeric bladder, a see-through PED to validate the expulsion process and model, and a complete UCPS-based PED with stringers and skirts that will be used to conduct initial qualification and expulsion tests. This extends the UCPS technology to include hydrazine-based, in-space pro - pulsion applications and can also be used for electric propulsion. This innovation creates a system that, in comparison to the traditional approach, is lower in weight, cost, volume, and production time; is stronger; and is capable of much higher pressures. It also has fewer failure modes, and is applicable to both chemical and electric propulsion systems.

Rufer, Markus; Conger, Robert; Bauer, Thomas; Newman, John

2013-01-01

322

Randomised, controlled trial of alternating pressure mattresses compared with alternating pressure overlays for the prevention of pressure ulcers: PRESSURE (pressure relieving support surfaces) trial  

Microsoft Academic Search

Objective To compare whether differences exist between alternating pressure overlays and alternating pressure mattresses in the development of new pressure ulcers, healing of existing pressure ulcers, and patient acceptability. Design Pragmatic, open, multicentre, randomised controlled trial. Setting 11 hospitals in six NHS trusts. Participants 1972 people admitted to hospital as acute or elective patients. Interventions Participants were randomised to an

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

2006-01-01

323

Conflicting Selection Pressures  

NSDL National Science Digital Library

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

Consortium, The C.

2012-01-13

324

Urodynamic pressure sensor  

NASA Technical Reports Server (NTRS)

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

Moore, Thomas

1991-01-01

325

Melting at High Pressures  

NASA Astrophysics Data System (ADS)

At high pressures, melts tend to become more similar to the crystalline solid phases. In general, the change in volume with melting, ? V, becomes small and the entropy of melting, ? S, becomes constant leading to a melting curve that bends over and approaches a constant. [1] Solids near melting also show approaching dynamical instabilities near melting, such as enhanced diffusivities in a premelting region. [2] Some materials display different behavior. Na, for example, shows a melting curve with a maximum followed by a negative pressure slope down to low temperatures. [3] Raty et al. proposed that the electronic structure of liquid and solid sodium are different, due to opening of a pseudogap in liquid Na, leading to increased density of the liquid and a negative melting slope. [4] We have performed first-principles molecular dynamics simulations for solid and liquid sodium as a function of P and T, and find no evidence of a pseudogap or electronic transition in Na. Rather we find that liquid Na is denser due to closer first neighbors with icosohedral packing due to softening of the potential such as occurs in a Gaussian core potential. We are also performing first-principles MD for Mg2SiO4 liquid to understand diffusivity and dynamical properties of the melt using the QBOX code. Initial results show D=(14, 3.2, 16) 10-6 m2/s for (Mg,Si,O) at P=0 and 6000K and D=(5.7, 1.9, 9.2) 10-6 m2/s at 5000K. Lower temperature and higher pressure simulations are in progress. [1] R. E. Cohen, and Z. Gong, Phys. Rev. B 50, 12301 (1994). [2] R. E. Cohen, and J. Weitz, in Properties of Earth and Planetary Materials at High Pressure and Temperature, edited by M. H. Manghnani, and T. Yagi (AGU, Washington, D.C., 1998), pp. 185. [3] E. Gregoryanz et al., Phys. Rev. Lett. 94, 185502 (2005). [4] J.-Y. Raty, E. Schwegler, and S. A. Bonev, Nature 449, 448 (2007). [5] F. H. Stillinger, and P. G. Debenedetti, Biophysical Chemistry 105, 211 (2003).

Cohen, R. E.; Vorberger, J.; Militzer, B.; Caracas, R.; Gygi, F.

2008-12-01

326

Apparatus for absolute pressure measurement  

NASA Technical Reports Server (NTRS)

An absolute pressure sensor (e.g., the diaphragm of a capacitance manometer) was subjected to a superimposed potential to effectively reduce the mechanical stiffness of the sensor. This substantially increases the sensitivity of the sensor and is particularly useful in vacuum gauges. An oscillating component of the superimposed potential induced vibrations of the sensor. The phase of these vibrations with respect to that of the oscillating component was monitored, and served to initiate an automatic adjustment of the static component of the superimposed potential, so as to bring the sensor into resonance at the frequency of the oscillating component. This establishes a selected sensitivity for the sensor, since a definite relationship exists between resonant frequency and sensitivity.

Hecht, R. (inventor)

1969-01-01

327

Management of Chronic Pressure Ulcers  

PubMed Central

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

2009-01-01

328

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

329

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

330

Airway obstruction with cricoid pressure.  

PubMed

Cricoid pressure may cause airway obstruction. We investigated whether this is related to the force applied and to the technique of application. We recorded expired tidal volumes and inflation pressures during ventilation via a face-mask and oral airway in 52 female patients who were anaesthetised and about to undergo elective surgery. An inspired tidal volume of 900 ml was delivered using a ventilator. Ventilation was assessed under five different conditions: no cricoid pressure, backwards cricoid pressure applied with a force of 30 N, cricoid pressure applied in an upward and backward direction with a force of 30 N, backwards cricoid pressure with a force of 44 N and through a tracheal tube. An expired tidal volume of < 200 ml was taken to indicate airway obstruction. Airway obstruction did not occur without cricoid pressure, but did occur in one patient (2%) with cricoid pressure at 30 N, in 29 patients (56%) with 30 N applied in an upward and backward direction and in 18 (35%) patients with cricoid pressure at 44 N. Cricoid pressure applied with a force of 44 N can cause airway obstruction but if cricoid pressure is applied with a force of 30 N, airway obstruction occurs less frequently (p = 0.0001) unless the force is applied in an upward and backward direction. PMID:10671836

Hartsilver, E L; Vanner, R G

2000-03-01

331

The vapor pressures of explosives  

SciTech Connect

The vapor pressures of many explosive compounds are extremely low and thus determining accurate values proves difficult. Many researchers, using a variety of methods, have measured and reported the vapor pressures of explosives compounds at single temperatures, or as a function of temperature using vapor pressure equations. There are large variations in reported vapor pressures for many of these compounds, and some errors exist within individual papers. This article provides a review of explosive vapor pressures and describes the methods used to determine them. We have compiled primary vapor pressure relationships traceable to the original citations and include the temperature ranges for which they have been determined. Corrected values are reported as needed and described in the text. In addition, after critically examining the available data, we calculate and tabulate vapor pressures at 25 °C.

Ewing, Robert G.; Waltman, Melanie J.; Atkinson, David A.; Grate, Jay W.; Hotchkiss, Peter

2013-01-05

332

Assessment of fiber optic pressure sensors  

SciTech Connect

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

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

1995-04-01

333

Thermodynamic equilibrium at heterogeneous pressure  

NASA Astrophysics Data System (ADS)

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

Vrijmoed, Johannes C.; Podladchikov, Yuri Y.

2014-05-01

334

Pressure Measurement Sensor  

NASA Technical Reports Server (NTRS)

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

1997-01-01

335

Pressure vessel bottle mount  

NASA Technical Reports Server (NTRS)

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

Wingett, Paul (Inventor)

2001-01-01

336

High pressure mechanical seal  

NASA Technical Reports Server (NTRS)

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

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

1995-01-01

337

High pressure mechanical seal  

NASA Technical Reports Server (NTRS)

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

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

1996-01-01

338

Effects of pressure waves  

NASA Technical Reports Server (NTRS)

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

1977-01-01

339

A Constant Pressure Bomb  

NASA Technical Reports Server (NTRS)

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

Stevens, F W

1924-01-01

340

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

341

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.

342

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

NASA Astrophysics Data System (ADS)

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

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

2003-03-01

343

Gas/oil capillary pressure at chalk at elevated pressures  

SciTech Connect

Accurate capillary pressure curves are essential for studying the recovery of oil by gas injection in naturally fractured chalk reservoirs. A simple and fast method to determine high-pressure drainage capillary pressure curves has been developed. The effect of gas/oil interfacial tension (IFT) on the capillary pressure of chalk cores has been determined for a methane/n-pentane system. Measurements on a 5-md outcrop chalk core were made at pressures of 70, 105, and 130 bar, with corresponding IFT`s of 6.3, 3.2, and 1.5 mN/m. The results were both accurate and reproducible. The measured capillary pressure curves were not a linear function of IFT when compared with low-pressure centrifuge data. Measured capillary pressures were considerably lower than IFT-scaled centrifuge data. It appears that the deviation starts at an IFT of about 5 mN/m. According to the results of this study, the recovery of oil by gravity drainage in naturally fractured chalk reservoirs may be significantly underestimated if standard laboratory capillary pressure curves are scaled by IFT only. However, general conclusions cannot be made on the basis on only this series of experiments on one chalk core.

Christoffersen, K.R. [Statoil Research Centre, Trondheim (Norway); Whitson, C.H. [Univ. of Trondheim (Norway)

1995-09-01

344

14 CFR 23.843 - Pressurization tests.  

Code of Federal Regulations, 2013 CFR

... § 23.843 Pressurization tests. (a) Strength test. The complete pressurized cabin, including doors, windows, canopy, and valves, must be tested as a pressure vessel for the pressure differential specified in § 23.365(d). (b)...

2013-01-01

345

14 CFR 23.843 - Pressurization tests.  

Code of Federal Regulations, 2010 CFR

... § 23.843 Pressurization tests. (a) Strength test. The complete pressurized cabin, including doors, windows, canopy, and valves, must be tested as a pressure vessel for the pressure differential specified in § 23.365(d). (b)...

2010-01-01

346

14 CFR 23.843 - Pressurization tests.  

Code of Federal Regulations, 2011 CFR

... § 23.843 Pressurization tests. (a) Strength test. The complete pressurized cabin, including doors, windows, canopy, and valves, must be tested as a pressure vessel for the pressure differential specified in § 23.365(d). (b)...

2011-01-01

347

14 CFR 23.843 - Pressurization tests.  

Code of Federal Regulations, 2012 CFR

... § 23.843 Pressurization tests. (a) Strength test. The complete pressurized cabin, including doors, windows, canopy, and valves, must be tested as a pressure vessel for the pressure differential specified in § 23.365(d). (b)...

2012-01-01

348

14 CFR 23.843 - Pressurization tests.  

Code of Federal Regulations, 2014 CFR

... § 23.843 Pressurization tests. (a) Strength test. The complete pressurized cabin, including doors, windows, canopy, and valves, must be tested as a pressure vessel for the pressure differential specified in § 23.365(d). (b)...

2014-01-01

349

49 CFR 195.304 - Test pressure.  

Code of Federal Regulations, 2011 CFR

...2011-10-01 2011-10-01 false Test pressure. 195.304 Section 195.304 Transportation...TRANSPORTATION OF HAZARDOUS LIQUIDS BY PIPELINE Pressure Testing § 195.304 Test pressure. The test pressure for each...

2011-10-01

350

49 CFR 195.304 - Test pressure.  

Code of Federal Regulations, 2013 CFR

...2013-10-01 2013-10-01 false Test pressure. 195.304 Section 195.304 Transportation...TRANSPORTATION OF HAZARDOUS LIQUIDS BY PIPELINE Pressure Testing § 195.304 Test pressure. The test pressure for each...

2013-10-01

351

46 CFR 154.452 - External pressure.  

Code of Federal Regulations, 2011 CFR

...2011-10-01 2011-10-01 false External pressure. 154.452 Section 154.452 Shipping...Equipment Independent Tank Type C and Process Pressure Vessels § 154.452 External pressure. The design external pressure, Pe...

2011-10-01

352

46 CFR 154.452 - External pressure.  

Code of Federal Regulations, 2010 CFR

...2010-10-01 2010-10-01 false External pressure. 154.452 Section 154.452 Shipping...Equipment Independent Tank Type C and Process Pressure Vessels § 154.452 External pressure. The design external pressure, Pe...

2010-10-01

353

46 CFR 154.452 - External pressure.  

Code of Federal Regulations, 2014 CFR

...2014-10-01 2014-10-01 false External pressure. 154.452 Section 154.452 Shipping...Equipment Independent Tank Type C and Process Pressure Vessels § 154.452 External pressure. The design external pressure, Pe...

2014-10-01

354

49 CFR 195.304 - Test pressure.  

Code of Federal Regulations, 2012 CFR

...2012-10-01 2012-10-01 false Test pressure. 195.304 Section 195.304 Transportation...TRANSPORTATION OF HAZARDOUS LIQUIDS BY PIPELINE Pressure Testing § 195.304 Test pressure. The test pressure for each...

2012-10-01

355

33 CFR 159.109 - Pressure test.  

Code of Federal Regulations, 2014 CFR

...2014-07-01 2014-07-01 false Pressure test. 159.109 Section 159...Construction, and Testing § 159.109 Pressure test. Any sewage retention tank that is designed to operate under pressure must be pressurized...

2014-07-01

356

46 CFR 154.452 - External pressure.  

Code of Federal Regulations, 2013 CFR

...2013-10-01 2013-10-01 false External pressure. 154.452 Section 154.452 Shipping...Equipment Independent Tank Type C and Process Pressure Vessels § 154.452 External pressure. The design external pressure, Pe...

2013-10-01

357

46 CFR 154.452 - External pressure.  

Code of Federal Regulations, 2012 CFR

...2012-10-01 2012-10-01 false External pressure. 154.452 Section 154.452 Shipping...Equipment Independent Tank Type C and Process Pressure Vessels § 154.452 External pressure. The design external pressure, Pe...

2012-10-01

358

49 CFR 195.304 - Test pressure.  

Code of Federal Regulations, 2010 CFR

...2010-10-01 2010-10-01 false Test pressure. 195.304 Section 195.304 Transportation...TRANSPORTATION OF HAZARDOUS LIQUIDS BY PIPELINE Pressure Testing § 195.304 Test pressure. The test pressure for each...

2010-10-01

359

Pressure melting and ice skating  

NASA Astrophysics Data System (ADS)

Pressure melting cannot be responsible for the low friction of ice. The pressure needed to reach the melting temperature is above the compressive failure stress and, if it did occur, high squeeze losses would result in very thin films. Pure liquid water cannot coexist with ice much below -20 °C at any pressure and friction does not increase suddenly in that range. If frictional heating and pressure melting contribute equally, the length of the wetted contact could not exceed 15 ?m at a speed of 5 m/s, which seems much too short. If pressure melting is the dominant process, the water films are less than 0.08 ?m thick because of the high pressures.

Colbeck, S. C.

1995-10-01

360

High pressure, high temperature transducer  

NASA Technical Reports Server (NTRS)

The pressure measurement system utilizes two bourdon tubes with an active side connected to a test specimen and a reference side connected to an outside source. The tubes are attached to a single extensometer measuring relative displacement. The active side deflects when gases vent a specimen failure. The reference side is independently pressurized to a test pressure and provides a zero reference while providing a pressure calibration reference for the active side. The deflection noted by the active side at specimen failure is duplicated on the reference side by venting until an appropriate magnitude of pressure versus deflection is determined. In this way the pressure which existed inside the specimen prior to failure can be determined.

Vrolyk, John J. (Inventor)

1977-01-01

361

Ambulatory Monitoring of Blood Pressure  

Microsoft Academic Search

Ambulatory blood pressure monitoring (ABPM) has been available for more than 40 yr, but its use has been primarily restricted\\u000a to research trials. Ambulatory blood pressure (ABP) monitors are becoming increasingly popular in clinical medicine. The numerous\\u000a benefits include the avoidance of potential blood pressure measurement errors such as observer bias and terminal digit preference\\u000a and provision of more comprehensive

Subramanian Krishnan; William B. White

362

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 PMID:21221298

Jordan, John M.

1992-01-01

363

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

364

Multilayer Composite Pressure Vessels  

NASA Technical Reports Server (NTRS)

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

DeLay, Tom

2005-01-01

365

High pressure synthesis gas fermentation  

SciTech Connect

Construction of the high pressure gas phase fermentation system is nearing completion. All non-explosion proof components will be housed separately in a gas-monitored plexiglas cabinet. A gas-monitoring system has been designed to ensure the safety of the operations in case of small or large accidental gas releases. Preliminary experiments investigating the effects of high pressure on Clostridium 1jungdahlii have shown that growth and CO uptake are not negatively affected and CO uptake by an increased total pressure of 100 psig at a syngas partial pressure of 10 psig.

Not Available

1991-01-01

366

Apollo experience report: Pressure vessels  

NASA Technical Reports Server (NTRS)

The Apollo spacecraft pressure vessels, associated problems and resolutions, and related experience in evaluating potential problem areas are discussed. Information is provided that can be used as a guideline in the establishment of baseline criteria for the design and use of lightweight pressure vessels. One of the first practical applications of the use of fracture-mechanics technology to protect against service failures was made on Apollo pressure vessels. Recommendations are made, based on Apollo experience, that are designed to reduce the incidence of failure in pressure-vessel operation and service.

Ecord, G. M.

1972-01-01

367

[High Pressure Gas Tanks  

NASA Technical Reports Server (NTRS)

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

Quintana, Rolando

2002-01-01

368

A dynamic pressure source for the calibration of pressure transducers  

NASA Technical Reports Server (NTRS)

A dynamic pressure source is described for producing sinusoidally varying pressures of up to 34 kPa zero to peak, over the frequency range of approximately 50 Hz to 2 kHz. The source is intended for the dynamic calibration of pressure transducers. The transducer to be calibrated is mounted near the base of the thick walled aluminum tube forming the vessel so that the pressure sensitive element is in contact with the liquid in the tube. A section of the tube is filled with small steel balls to damp the motion of the 10-St dimethyl siloxane working fluid in order to extend the useful frquency range to higher frequencies than would be provided by an undamped system. The dynamic response of six transducers provided by the sponsor was evaluated using the pressure sources; the results of these calibrations are given.

Vezzetti, C. F.; Hilten, J. S.; Mayo-Wells, J. F.; Lederer, P. S.

1976-01-01

369

Desorption atmospheric pressure photoionization.  

PubMed

An ambient ionization technique for mass spectrometry, desorption atmospheric pressure photoionization (DAPPI), is presented, and its application to the rapid analysis of compounds of various polarities on surfaces is demonstrated. The DAPPI technique relies on a heated nebulizer microchip delivering a heated jet of vaporized solvent, e.g., toluene, and a photoionization lamp emitting 10-eV photons. The solvent jet is directed toward sample spots on a surface, causing the desorption of analytes from the surface. The photons emitted by the lamp ionize the analytes, which are then directed into the mass spectrometer. The limits of detection obtained with DAPPI were in the range of 56-670 fmol. Also, the direct analysis of pharmaceuticals from a tablet surface was successfully demonstrated. A comparison of the performance of DAPPI with that of the popular desorption electrospray ionization method was done with four standard compounds. DAPPI was shown to be equally or more sensitive especially in the case of less polar analytes. PMID:17803282

Haapala, Markus; Pól, Jaroslav; Saarela, Ville; Arvola, Ville; Kotiaho, Tapio; Ketola, Raimo A; Franssila, Sami; Kauppila, Tiina J; Kostiainen, Risto

2007-10-15

370

Automated office blood pressure.  

PubMed

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

Myers, Martin G; Godwin, Marshall

2012-05-01

371

Tectonic pressure: Theoretical concepts and modelled examples  

NASA Astrophysics Data System (ADS)

Pressure variation due to deformation is an intrinsic property of fracture and flow in all materials, including rocks under geological conditions. Strong gradients occur at rheological boundaries (due to inclusions, layers, channels, shear zones, boudin necks, etc) and these gradients are instrumental in driving local pore fluid and/or melt flow during deformation. The pressure distribution in deforming rocks is not static, but changes in space and time. A clear and relevant natural example is the variation during buckle folding of strong layers embedded in a weak matrix. Local pressure gradients and magnitudes can therefore change without any associated change in depth. The magnitude of tectonic pressure is determined by a non-dimensional pressure parameter, reflecting geometry and position, and a scaling factor, with units of stress (Pa), given by the strength of the rock. Brittle fracture places an upper limit on rock strength. For Mohr-Coulomb yield, the tectonic overpressure is equal to the effective vertical load (or "lithostatic pressure"- pore fluid pressure) in the case of plane strain crustal shortening. Deep seismic failure in relatively dry rocks, as recorded by pseudotachylytes developed under lower crustal or even eclogitic conditions, is therefore direct evidence for significant tectonic pressure. For viscous materials, tectonic pressure scales linearly with flow stress, or alternatively with the effective viscosity and strain rate. Typical tectonic pressures related to folds, boudins, or strong inclusions are of order 1-2 times the maximum shear stress that the strong material can support. However, even geologically weak materials (e.g. effective viscosity 10 19-10 20 Pa s) can develop very significant tectonic pressures (on the order of many 100's of MPa to several GPa) when the flow is confined, such as during extrusion or convergent channel flow between strong walls, as has been proposed for active subduction zones. The maximum overpressure in this case is limited by the strength of the confining walls, which do not have to be unrealistically strong (or rigid) for the development of significant tectonic pressures.

Mancktelow, Neil S.

2008-06-01

372

Plot procedure finds closure pressure  

Microsoft Academic Search

A procedure has been developed for using a log-log plot of pressure decline to identify different flow regimes following microfrac or minifrac. Coupled with the square of time plot, it is possible to verify that the straight line used for determining closure pressure is a correct one. A log-log plot has been used as a diagnostic tool for identifying various

Sookprasong

1986-01-01

373

Blood Pressure Control Goes Nuclear  

Microsoft Academic Search

he control of blood pressure is regulated with extreme precision, and requires integration of information from the central nervous system, the kidneys, the vasculature, and the heart. Salt and water balances, sympa- thetic activity, arterial stiffness, and the tone of resistance vessels determine the chronic regulation of intravascular pressure. It is a standard experiment for physicians-in- training to manipulate these

Cam Patterson

2010-01-01

374

Magnetospheric equilibrium with anisotropic pressure  

SciTech Connect

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

Cheng, C.Z.

1991-07-01

375

High amplitude sinusoidal pressure generator  

NASA Technical Reports Server (NTRS)

Generator is an inlet-area-modulated, gas-flow-through device utilizing hydrogen gas and a rotating disk for operation. Design enables generator to produce pressure oscillations as high as 120, 18, and 12 percent of the mean chamber pressure at frequencies of 1, 10, and 15 kHz, respectively.

Robinson, R. E.

1970-01-01

376

Low frequency sinusoidal pressure generator  

NASA Technical Reports Server (NTRS)

Low frequency pressure generator is built to provide sinusoidal driving function in frequency range from 0.05 to 50 Hz for frequency response testing of pressure transducers used in liquid-filled systems. Generator consists of piston-in-cylinder, scotch-yoke mechanism machined into piston, and adjustable eccentric.

Curreri, J. S.

1972-01-01

377

Particle pressures in fluidized beds  

SciTech Connect

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

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

1992-01-01

378

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

379

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

380

Pressure Reducer for Coal Gasifiers  

NASA Technical Reports Server (NTRS)

Quasi-porous-plug pressure reducer is designed for gases containing abrasive particles. Gas used to generate high pressure steam to drive electric power generators. In giving up heat to steam, gas drops in temperature. Device used for coal gasification plants.

Kendall, James M., Sr.

1983-01-01

381

Paediatric blood pressure and anaesthesia.  

PubMed

One percent of children have appreciably and consistently raised arterial blood pressure. A 7-year-old girl admitted for routine tonsillectomy, had unrecognised hypertension which put her at increased risk. Should anaesthetic practice take more note of paediatric blood pressures? PMID:2035786

Mather, C M

1991-05-01

382

Microwave Atmospheric-Pressure Sensor  

NASA Technical Reports Server (NTRS)

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

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

1986-01-01

383

Hydrogen Pressure Vessel Testing Program  

Microsoft Academic Search

The Hydrogen Pressure Vessel Testing Program has been designed to meet two objectives, including: 1) providing visual and quantitative information to OEM's, regulatory agencies, and the public, regarding the consequences of on-board high pressure hydrogen as a fuel source and 2) through a collaborative effort with experts in the field, use the data generated from this project to provide a

Ben C. Odegard Jr; George J. Thomas

384

Passive Pressure Determination by Method of Slices  

NASA Astrophysics Data System (ADS)

A method of slices satisfying all the conditions of statical equilibrium has been developed to deal with the problem of determination of passive earth pressure over a retaining wall in sand. A method similar to that of Morgenstern and Price, which was used to solve the stability of slopes, has been followed. The earth pressure coefficients with the proposed methodology have been computed for a vertical retaining wall for both positive and negative wall friction angle. Also examined is the variation of the interslice shear force between the retaining wall and the Rankine Passive boundary. Due to complete satisfaction of the equilibrium conditions, the method generates exactly the same earth pressure coefficients as computed by using Terzaghi's overall limit equilibrium approach.

Kumar, Jyant; Subba Rao, Kanakapura S.

1997-05-01

385

Pressurized Lunar Rover (PLR)  

NASA Technical Reports Server (NTRS)

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

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

1992-01-01

386

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

387

Electrical conductivity of hydrogen shocked to megabar pressures  

SciTech Connect

The properties of ultra-high pressure hydrogen have been the subject of much experimental and theoretical study. Of particular interest is the pressure-induced insulator-to-metal transition of hydrogen which, according to recent theoretical calculations, is predicted to occur by band-overlap in the pressure range of 1.5-3.0 Mbars on the zero temperature isotherm. Extremely high pressures are required for metallization since the low-pressure band gap is about 15 eV. Recent static-pressure diamond anvil cell experiments have searched for evidence of an insulator-to-metal transition, but no conclusive evidence for such a transition has yet been supplied. Providing conclusive evidence for hydrogen metallization is difficult because no technique has yet been developed for performing static high-pressure electrical conductivity experiments at megabar pressures. The authors report here on electrical conductivity experiments performed on H{sub 2} and D{sub 2} multi-shocked to megabar pressures. Electrical conductivities of dense fluid hydrogen at these pressures and temperatures reached are needed for calculations of the magnetic fields of Jupiter and Saturn, the magnetic fields being generated by convective dynamos of hot, dense, semiconducting fluid hydrogen. Also, since electrical conduction at the pressure-temperature conditions being studied is due to the thermal excitation of charge carriers across the electronic band gap, these experiments yield valuable information on the width of the band gap at high densities.

Weir, S.T.; Nellis, W.J.; Mitchell, A.C.

1993-08-01

388

Experimental study of the flow in a vaneless diffuser with circumferential pressure distortion  

Microsoft Academic Search

Laser Doppler anemometry and static pressure measurements in the vaneless diffuser of a centrifugal compressor are presented. Measurements reveal that the outlet volute not only defines a circumferential pressure variation, but also influences the flow inside the impeller and the diffuser. The radial velocity variation along the circumference is found to be in phase with the static pressure while the

M. T. Sideris; R. A. Vandenbraembussche

1986-01-01

389

Wrinkling of Pressurized Elastic Shells  

NASA Astrophysics Data System (ADS)

We study the formation of localized structures formed by the point loading of an internally pressurized elastic shell. While unpressurized shells (such as a ping-pong ball) buckle into polygonal structures, we show that pressurized shells are subject to a wrinkling instability. We study wrinkling in depth, presenting scaling laws for the critical indentation at which wrinkling occurs and the number of wrinkles formed in terms of the internal pressurization and material properties of the shell. These results are validated by numerical simulations. We show that the evolution of the wrinkle length with increasing indentation can be understood for highly pressurized shells from membrane theory. These results suggest that the position and number of wrinkles may be used in combination to give simple methods for the estimation of the mechanical properties of highly pressurized shells.

Vella, Dominic; Ajdari, Amin; Vaziri, Ashkan; Boudaoud, Arezki

2011-10-01

390

Fundamentals of high pressure adsorption  

SciTech Connect

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.

Zhou, Y.P.; Zhou, L. [Tianjin University, Tianjin (China). High Pressure Adsorption Laboratory

2009-12-15

391

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.

2010-04-01

392

High-pressure and temperature investigations of energetic materials  

NASA Astrophysics Data System (ADS)

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

Gump, J. C.

2014-05-01

393

Buckling of Externally Pressurized Shallow Spherical Caps from Composites  

Microsoft Academic Search

Buckling of shallow spherical shells subjected to external pressure has been exploited, for example, in pressure safety devices. Shallow spherical caps have also been used as mirrors and more recently they have been considered as energy concentrators in space applications. Hence there is a renewed interest in their static stability performance. This paper addresses two issues: (1) buckling performance of

Jan B?achut

2011-01-01

394

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

NASA Technical Reports Server (NTRS)

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

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

1984-01-01

395

An experimental study of transonic flow about a supercritical airfoil. Static pressure and drag data obtained from tests of a supercritical airfoil and an NACA 0012 airfoil at transonic speeds, supplement  

NASA Technical Reports Server (NTRS)

Surface static-pressure and drag data obtained from tests of two slightly modified versions of the original NASA Whitcomb airfoil and a model of the NACA 0012 airfoil section are presented. Data for the supercritical airfoil were obtained for a free-stream Mach number range of 0.5 to 0.9, and a chord Reynolds number range of 2 x 10 to the 6th power to 4 x 10 to the 6th power. The NACA 0012 airfoil was tested at a constant chord Reynolds number of 2 x 10 to the 6th power and a free-stream Mach number range of 0.6 to 0.8.

Spaid, F. W.; Dahlin, J. A.; Roos, F. W.; Stivers, L. S., Jr.

1983-01-01

396

42 CFR 84.157 - Airflow resistance test; Type C supplied-air respirator, pressure-demand class; minimum...  

Code of Federal Regulations, 2013 CFR

...supplied-air respirator, pressure-demand class; minimum...requirements. (a) The static pressure in the facepiece shall...water-column height. (b) The pressure in the facepiece shall not fall below atmospheric at inhalation...

2013-10-01

397

42 CFR 84.157 - Airflow resistance test; Type C supplied-air respirator, pressure-demand class; minimum...  

Code of Federal Regulations, 2012 CFR

...supplied-air respirator, pressure-demand class; minimum...requirements. (a) The static pressure in the facepiece shall...water-column height. (b) The pressure in the facepiece shall not fall below atmospheric at inhalation...

2012-10-01

398

42 CFR 84.157 - Airflow resistance test; Type C supplied-air respirator, pressure-demand class; minimum...  

Code of Federal Regulations, 2010 CFR

...supplied-air respirator, pressure-demand class; minimum...requirements. (a) The static pressure in the facepiece shall...water-column height. (b) The pressure in the facepiece shall not fall below atmospheric at inhalation...

2010-10-01

399

42 CFR 84.157 - Airflow resistance test; Type C supplied-air respirator, pressure-demand class; minimum...  

Code of Federal Regulations, 2011 CFR

...supplied-air respirator, pressure-demand class; minimum...requirements. (a) The static pressure in the facepiece shall...water-column height. (b) The pressure in the facepiece shall not fall below atmospheric at inhalation...

2011-10-01

400

42 CFR 84.157 - Airflow resistance test; Type C supplied-air respirator, pressure-demand class; minimum...  

Code of Federal Regulations, 2014 CFR

...Type C supplied-air respirator, pressure-demand class; minimum requirements...Type C supplied-air respirator, pressure-demand class; minimum requirements. (a) The static pressure in the facepiece shall not exceed...

2014-10-01

401

Dynamic-pressure measurements using an electronically scanned pressure module  

NASA Technical Reports Server (NTRS)

Frequency response was measured for different lengths and diameters of tubing between a sinusoidal pressure source and a pressure sensing module from an electronically scanned pressure measuring system. Measurements were made for straight runs of both steel and vinyl tubing. For steel tubing, measured results are compared with results calculated by using equations developed by Tijdeman and Bergh. Measurements were also made with a bend in the vinyl tubing at the module. In addition, measurements were made with two coils placed in the tubing near the middle of the run.

Chapin, W. G.

1983-01-01

402

Delta wing surface pressures for high angle of attack maneuvers  

NASA Technical Reports Server (NTRS)

A wind tunnel experiment was performed on a delta wing with a leading edge sweep of 70 deg. Unsteady pressures were measured on the suction surface of the wing as it was oscillated from 0-30 deg, and 2-60 deg angle-of-attack. Pressure coefficients were measured at different surface locations for two pitch rates. Static pressure measurements were also obtained for comparison with the dynamic results. The Reynolds number was fixed at 420,000, based on the centerline chord length. Pressure measurements were made from 35-90 percent of the chord, along a ray from the apex at 60 percent of the local semispan. Spanwise measurements were also made at a constant chord location, x/c = 75 percent from the apex. The unsteady pressure data over the 0-30 deg angle-of-attack range showed pressures fluctuating in phase with model motion, and little overshoot from the static values. The pressures for the large amplitude motion showed large overshoots from the static values. In addition, during the high angle-of-attack portion of the motion, the upstroke (angle of attack increasing) pressure coefficients were typically much lower than the downstroke values. For the lower pitch rate, there was little difference between upstroke and downstroke pressures at the low angles of attack.

Thompson, S. A.; Batill, S. M.; Nelson, R. C.

1990-01-01

403

Serotonin and Blood Pressure Regulation  

PubMed Central

5-Hydroxytryptamine (5-HT; serotonin) was discovered more than 60 years ago as a substance isolated from blood. The neural effects of 5-HT have been well investigated and understood, thanks in part to the pharmacological tools available to dissect the serotonergic system and the development of the frequently prescribed selective serotonin-reuptake inhibitors. By contrast, our understanding of the role of 5-HT in the control and modification of blood pressure pales in comparison. Here we focus on the role of 5-HT in systemic blood pressure control. This review provides an in-depth study of the function and pharmacology of 5-HT in those tissues that can modify blood pressure (blood, vasculature, heart, adrenal gland, kidney, brain), with a focus on the autonomic nervous system that includes mechanisms of action and pharmacology of 5-HT within each system. We compare the change in blood pressure produced in different species by short- and long-term administration of 5-HT or selective serotonin receptor agonists. To further our understanding of the mechanisms through which 5-HT modifies blood pressure, we also describe the blood pressure effects of commonly used drugs that modify the actions of 5-HT. The pharmacology and physiological actions of 5-HT in modifying blood pressure are important, given its involvement in circulatory shock, orthostatic hypotension, serotonin syndrome and hypertension. PMID:22407614

Morrison, Shaun F.; Davis, Robert Patrick; Barman, Susan M.

2012-01-01

404

High Blood Pressure: Using an Ambulatory Blood Pressure Monitor  

MedlinePLUS

... can be worn under your clothes without anyone seeing it. The picture to the right shows a person wearing an ambulatory blood pressure monitor. This machine records and lets your doctor find out what ...

405

Heat transfer and pressure measurements for the SSME fuel turbine  

NASA Astrophysics Data System (ADS)

A measurement program is underway using the Rocketdyne two-stage Space Shuttle Main Engine (SSME) fuel turbine. The measurements use a very large shock tunnel to produce a short-duration source of heated and pressurized gas which is subsequently passed through the turbine. Within this environment, the turbine is operated at the design values of flow function, stage pressure ratio, stage temperature ratio, and corrected speed. The first stage vane row and the first stage blade row are instrumented in both the spanwise and chordwise directions with pressure transducers and heat flux gages. The specific measurements to be taken include time averaged surface pressure and heat flux distributions on the vane and blade, flow passage static pressure, flow passage total pressure and total temperature distributions, and phase resolved surface pressure and heat flux on the blade.

Dunn, Michael G.; Kim, Jungho

1991-05-01

406

Precision ozone vapor pressure measurements  

NASA Technical Reports Server (NTRS)

The vapor pressure above liquid ozone has been measured with a high accuracy over a temperature range of 85 to 95 K. At the boiling point of liquid argon (87.3 K) an ozone vapor pressure of 0.0403 Torr was obtained with an accuracy of + or - 0.7 percent. A least square fit of the data provided the Clausius-Clapeyron equation for liquid ozone; a latent heat of 82.7 cal/g was calculated. High-precision vapor pressure data are expected to aid research in atmospheric ozone measurements and in many laboratory ozone studies such as measurements of cross sections and reaction rates.

Hanson, D.; Mauersberger, K.

1985-01-01

407

Arterial pulse wave pressure transducer  

NASA Technical Reports Server (NTRS)

An arterial pulse wave pressure transducer is introduced. The transducer is comprised of a fluid filled cavity having a flexible membrane disposed over the cavity and adapted to be placed on the skin over an artery. An arterial pulse wave creates pressure pulses in the fluid which are transduced, by a pressure sensitive transistor in direct contact with the fluid, into an electric signal. The electrical signal is representative of the pulse waves and can be recorded so as to monitor changes in the elasticity of the arterial walls.

Kim, C.; Gorelick, D.; Chen, W. (inventors)

1974-01-01

408

Graphite filament wound pressure vessels  

NASA Technical Reports Server (NTRS)

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

Feldman, A.; Damico, J. J.

1972-01-01

409

Gas Hydrate and Pore Pressure  

NASA Astrophysics Data System (ADS)

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

Tinivella, Umberta; Giustiniani, Michela

2014-05-01

410

Pressure sensor for sealed containers  

DOEpatents

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

Hodges, Franklin R. (Loudon, TN)

2001-01-01

411

High pressure pulsed capillary viscometry  

NASA Technical Reports Server (NTRS)

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

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

1972-01-01

412

Electrokinetic high pressure hydraulic system  

DOEpatents

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

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

2000-01-01

413

How Can High Blood Pressure Be Prevented?  

MedlinePLUS

... the NHLBI on Twitter. How Can High Blood Pressure Be Prevented? If You Have Normal Blood Pressure If you don't have high blood pressure ( ... Blood Pressure Treated?" If You Have High Blood Pressure If you have HBP, you can still take ...

414

MEASURING VARIATIONS IN TEMPERATURE AND PRESSURE  

E-print Network

MEASURING VARIATIONS IN TEMPERATURE AND PRESSURE A Balloon Experiment by: John Bertinetti and Chip Keating #12;Purpose of the Balloon Experiment Pressure and temperature vary with altitude: pressure;Pressure: P vs. h #12;Temperature: Exponential Curve Fit Note: this is a curve, not a line #12;Our pressure

California at Santa Cruz, University of

415

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

416

Reducing catalytic converter pressure loss  

SciTech Connect

This article examines why approximately 30--40% of total exhaust-system pressure loss occurs in the catalytic converter and what can be done to reduce pressure loss. High exhaust-system backpressure is of concern in the design of power trains for passenger cars and trucks because it penalizes fuel economy and limits peak power. Pressure losses occur due to fluid shear and turning during turbulent flow in the converter headers and in entry separation and developing laminar-flow boundary layers within the substrate flow passages. Some of the loss mechanisms are coupled. For example, losses in the inlet header are influenced by the presence of the flow resistance of a downstream substrate. Conversely, the flow maldistribution and pressure loss of the substrate(s) depend on the design of the inlet header.

NONE

1996-06-01

417

High Pressure Industrial Water Facility  

NASA Technical Reports Server (NTRS)

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

1992-01-01

418

Detrusor urethral sphincter dyssynergia: micturitional vesicourethral pressure profile patterns.  

PubMed

Vesicourethral static pressure recordings were attempted in patients with detrusor urethral sphincter dyssynergia. The technique consisted of recording vesicourethral pressures at successive points, commencing in the lower segment of the bladder during micturition. A small catheter with side holes was used for this purpose and static (lateral) pressure profile recordings were attempted during voiding. Successful static pressure recordings were obtained only in those patients who could expel urine as uninterrupted stream. Patients who could not void or those who could void only with interrupted stream have demonstrated profile patterns that required careful interpretation. The accuracy of urodynamic interpretation also depended upon careful clinical evaluation and awareness of the built-in artifacts of the technique. PMID:7176062

Yalla, S V; Yap, W; Fam, B A

1982-11-01

419

RBMK pressure tube rupture assessment  

SciTech Connect

The Russian RBMK reactor core design consists of multiple parallel pressure tube channels that contain Zr clad, UO{sub 2} fuel pin bundles. These parallel channels are contained within graphite moderator blocks which are, in turn, contained within a sealed core cavity. Current safety evaluation efforts of the RBMK reactors have been concentrating in the area of tube ruptures within the core cavity and, in particular, multiple tube ruptures that could threaten the reactor core integrity. Tube rupture events result in a pressurization of the reactor core cavity. The original design overpressure for the cavity region was based on a single tube rupture, resulting in considerable margin to the top plate lift pressure. The top plate lift pressure is 3.1 bar, and a single tube rupture would result in approximately 1.4 bar. RBMK plant specific cavity pressure relief designs provide for between three and in simultaneous tube ruptures before exceeding the top plate lift pressure. Thus, current safety evaluations have begun to examine the potential for multiple tube ruptures that could exceed the current cavity pressure relief designs. One such scenario being examined is a partial rupture in a group distribution header that results in stagnated (low) flow to up to 40 pressure tubes. The subsequent fuel heatup in these reduced flow tubes could result in multiple tube ruptures beyond the design relief capacity of the core cavity. This paper examines several key issues in evaluating this transient, including: (1) the effects of low flow, (2) the effects of axial peaking, and (3) the effects of radial peaking, all relative to the time to tube rupture. These issues each play a significant role in attempting to evaluate the likelihood and severity of multiple tube ruptures for a partial group distribution header break.

Schmitt, B.E.; Tsiklauri, G.V.

1994-08-01

420

Pressure Measurements across Vascular Stenoses  

PubMed Central

Summary We describe and analyze pressure measurements across vascular stenoses in an atherosclerotic human carotid bulb replica using catheters of different diameters. Replicas of an atherosclerotic human carotid bulb were created using the lost wax technique, and were placed in a circuit of pulsating non-newtonian fluid. Flows were adjusted to replicate human physiologic flow profiles. Common carotid artery total flow volume of 600 milliliters/minute was studied. A pressure recording device was calibrated; data were received from catheters placed longitudinally in the common carotid artery and internal carotid artery. The internal carotid artery pressures were obtained both through the stenosis as is usually performed in the angiography suite and through the vessel side-wall beyond the stenosis as a control. Internal carotid artery flow volumes were also measured with and without the catheter through the stenosis. Multiple pressure recordings and volume measurements were obtained in the replica using 7 French, 5 French, and 2.5 French catheters. Measurements of the replica showed a 58% diameter stenosis and an 89% area stenosis of the carotid bulb. All longitudinal pressure measurements in the common carotid artery agreed with control values regardless of the diameter of the catheter used. Pressure measurements were also in agreement with control values in the internal carotid artery using the 2.5 French catheter. However; when larger diameter catheters were employed, pressures measured with the catheter through the stenosis fell when compared to control values. Additionally, internal carotid artery flow volumes were also decreased when the larger diameter catheters were placed across the stenosis. Large diameter catheters when placed across vascular stenoses may cause an occlusive or near-occlusive state and artifactually increase the measured transstenotic vascular pressure gradient as well as decrease forward vascular flow. PMID:20670502

Imbesi, S.G.; Kerber, C.W.

1999-01-01

421

An atmospheric pressure plasma source  

Microsoft Academic Search

An atmospheric pressure plasma source operated by radio frequency power has been developed. This source produces a unique discharge that is volumetric and homogeneous at atmospheric pressure with a gas temperature below 300 °C. It also produces a large quantity of oxygen atoms, ~5×1015 cm-3, which has important value for materials applications. A theoretical model shows electron densities of 0.2-2×1011

Jaeyoung Park; I. Henins; H. W. Herrmann; G. S. Selwyn; J. Y. Jeong; R. F. Hicks; D. Shim; C. S. Chang

2000-01-01

422

Weather Stations: Temperature and Pressure  

NSDL National Science Digital Library

In this activity, learners discover the relationship between temperature and pressure in the lower atmospheres of Jupiter and Earth. Learners chart the increasing temperature as they add pressure to a 2-L soda bottle with a Fizz-Keeper Pump. This activity is one station that can be combined with other stations for an hour and half lesson on weather patterns on Jupiter and Earth.

2014-07-11

423

Membrane Bioreactor With Pressure Cycle  

NASA Technical Reports Server (NTRS)

Improved class of multilayer membrane bioreactors uses convention forced by differences in pressure to overcome some of diffusional limitations of prior bioreactors. In reactor of new class, flow of nutrient solution reduces adverse gradients of concentration, keeps cells supplied with fresh nutrient, and sweeps away products faster than diffusion alone. As result, overall yield and rate of reaction increased. Pressures in sweeping gas and nutrient alternated to force nutrient liquid into and out of biocatalyst layer through hyrophilic membrane.

Efthymiou, George S.; Shuler, Michael L.

1991-01-01

424

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

425

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

DOEpatents

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

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

2008-09-23

426

49 CFR 192.623 - Maximum and minimum allowable operating pressure; Low-pressure distribution systems.  

Code of Federal Regulations, 2013 CFR

... false Maximum and minimum allowable operating pressure; Low-pressure distribution systems. 192.623 Section 192...623 Maximum and minimum allowable operating pressure; Low-pressure distribution systems....

2013-10-01

427

49 CFR 192.623 - Maximum and minimum allowable operating pressure; Low-pressure distribution systems.  

Code of Federal Regulations, 2010 CFR

... false Maximum and minimum allowable operating pressure; Low-pressure distribution systems. 192.623 Section 192...623 Maximum and minimum allowable operating pressure; Low-pressure distribution systems....

2010-10-01

428

49 CFR 192.623 - Maximum and minimum allowable operating pressure; Low-pressure distribution systems.  

Code of Federal Regulations, 2011 CFR

... false Maximum and minimum allowable operating pressure; Low-pressure distribution systems. 192.623 Section 192...623 Maximum and minimum allowable operating pressure; Low-pressure distribution systems....

2011-10-01

429

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

Code of Federal Regulations, 2012 CFR

...2012-10-01 false Maximum allowable operating pressure: High-pressure distribution systems. 192.621 Section 192...Operations § 192.621 Maximum allowable operating pressure: High-pressure distribution systems....

2012-10-01

430

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

Code of Federal Regulations, 2013 CFR

...2013-10-01 false Maximum allowable operating pressure: High-pressure distribution systems. 192.621 Section 192...Operations § 192.621 Maximum allowable operating pressure: High-pressure distribution systems....

2013-10-01

431

49 CFR 192.623 - Maximum and minimum allowable operating pressure; Low-pressure distribution systems.  

Code of Federal Regulations, 2012 CFR

... false Maximum and minimum allowable operating pressure; Low-pressure distribution systems. 192.623 Section 192...623 Maximum and minimum allowable operating pressure; Low-pressure distribution systems....

2012-10-01

432

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....

2010-10-01

433

1 stepped pressure equilibrium code : hdfint 1 stepped pressure equilibrium code : hdfint 1  

E-print Network

1 stepped pressure equilibrium code : hdfint Contents 1 stepped pressure equilibrium code : hdfint enclosed by each interface; · pressure(1:Nvol); real; pressure in each volume; · iota(1:Nvol); real

Hudson, Stuart

434

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

Code of Federal Regulations, 2011 CFR

...2011-10-01 false Maximum allowable operating pressure: High-pressure distribution systems. 192.621 Section 192...Operations § 192.621 Maximum allowable operating pressure: High-pressure distribution systems....

2011-10-01

435

21 CFR 868.2700 - Pressure regulator.  

Code of Federal Regulations, 2010 CFR

...that is intended for medical purposes and that is used to convert a medical gas pressure from a high variable pressure to a lower, more constant working pressure. This device includes mechanical oxygen regulators. (b)...

2010-04-01

436

49 CFR 229.107 - Pressure gauge.  

Code of Federal Regulations, 2013 CFR

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

2013-10-01

437

49 CFR 229.107 - Pressure gauge.  

Code of Federal Regulations, 2012 CFR

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

2012-10-01

438

49 CFR 229.107 - Pressure gauge.  

Code of Federal Regulations, 2011 CFR

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

2011-10-01

439

49 CFR 229.107 - Pressure gauge.  

Code of Federal Regulations, 2010 CFR

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

2010-10-01

440

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 ... become damaged or die. When this happens, a pressure ulcer may form. Below are some questions you may ...

441

Constraints on Early Mars atmospheric pressure  

E-print Network

Constraints on Early Mars atmospheric pressure from small ancient craters impactors, so impact crater size is a probe of atmospheric pressure. ebar4bar Diameter (m) Fractionofcraterssmallerthan ! Atmospheric pressure upper limit

Kite, Edwin

442

How Is High Blood Pressure Diagnosed?  

MedlinePLUS Videos and Cool Tools

... are here Home » Health Information for the Public » Health Topics » High Blood Pressure » How Is High Blood Pressure Diagnosed? Explore High Blood Pressure What Is... Other Names Causes Who Is at Risk Signs & Symptoms Diagnosis Treatments Prevention Living With Clinical ...

443

46 CFR 119.330 - Pressure vessels.  

Code of Federal Regulations, 2010 CFR

...2010-10-01 2010-10-01 false Pressure vessels. 119.330 Section 119.330 Shipping...INSTALLATION Auxiliary Machinery § 119.330 Pressure vessels. All unfired pressure vessels must be installed to the satisfaction...

2010-10-01

444

46 CFR 182.330 - Pressure vessels.  

Code of Federal Regulations, 2010 CFR

...2010-10-01 2010-10-01 false Pressure vessels. 182.330 Section 182.330 Shipping...INSTALLATION Auxiliary Machinery § 182.330 Pressure vessels. All unfired pressure vessels must be installed to the...

2010-10-01

445

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

446

49 CFR 230.35 - Pressure testing.  

Code of Federal Regulations, 2011 CFR

... 2011-10-01 2011-10-01 false Pressure testing. 230.35 Section 230.35 ...MAINTENANCE STANDARDS Boilers and Appurtenances Pressure Testing of Boilers § 230.35 Pressure testing. The temperature of the...

2011-10-01

447

Avoid the Consequences of High Blood Pressure  

MedlinePLUS

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

448

49 CFR 230.35 - Pressure testing.  

Code of Federal Regulations, 2010 CFR

... 2010-10-01 2010-10-01 false Pressure testing. 230.35 Section 230.35 ...MAINTENANCE STANDARDS Boilers and Appurtenances Pressure Testing of Boilers § 230.35 Pressure testing. The temperature of the...

2010-10-01

449

49 CFR 230.35 - Pressure testing.  

Code of Federal Regulations, 2012 CFR

... 2012-10-01 2012-10-01 false Pressure testing. 230.35 Section 230.35 ...MAINTENANCE STANDARDS Boilers and Appurtenances Pressure Testing of Boilers § 230.35 Pressure testing. The temperature of the...

2012-10-01

450

49 CFR 230.35 - Pressure testing.  

Code of Federal Regulations, 2013 CFR

... 2013-10-01 2013-10-01 false Pressure testing. 230.35 Section 230.35 ...MAINTENANCE STANDARDS Boilers and Appurtenances Pressure Testing of Boilers § 230.35 Pressure testing. The temperature of the...

2013-10-01

451

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

NASA Technical Reports Server (NTRS)

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

Connors, James F

1950-01-01

452

Population pressures: threat to democracy.  

PubMed

The desire for political freedom and representative government is spreading throughout the world. The stability of democratic bodies is dependent on wise leaders, foreign aid, and slowing population growth. Rapid population growth strains political institutions and increases pressure on services. A Population Crisis Committee study found that only a few democratic countries with serious demographic pressures remained stable. The most stable countries were ones with lower levels of population pressure. Most of the 31 unstable countries were in Africa and in a band stretching from the Middle East to South Asia, and almost all had serious demographic pressures. Only 5 stable countries had high or very high demographic pressures. Since countries in the world are interdependent, population pressures have adverse consequences everywhere. Population pressures in the developing world are considered enhanced by the rapid growth of cities. Both the developed and the developing world face the problems of clogged highways, loss of wilderness, polluted lakes and streams, and stifling smog and acid rain conditions. The sociopolitical implications of demographic changes vary from country to country, but rapid growth and maldistribution of population strains existing political, social, and economic structures and relations between nations. Urban areas are the arena for clashes of cultures, competition for scarce housing and jobs, the breakdown of traditional family and social structures, and juxtapositions of extreme wealth next to extreme poverty. The growth of independent nation states since the 1940s has not allowed much time for development of effective political institutions. There are many obstacles to national unity and popular political participation. The potential for political instability is correlated with a number of factors: large youth populations in overcrowded cities with too high expectations and limited opportunities, diverse and intense ethnic and religious factors, and oppressive governments which violate human rights. Rapid growth has a harmful impact on the environment. PMID:12179234

1992-06-01

453

Flexible Pressure Sensors: Modeling and Experimental Characterization  

E-print Network

Flexible capacitive pressure sensors fabricated with nanocomposites were experimentally characterized and results compared with simulations from analytical modeling. Unlike traditional diaphragm silicon pressure sensors, ...

Viana, J.C.

454

Measuring Intracranial Pressure And Volume Noninvasively  

NASA Technical Reports Server (NTRS)

Ultrasonic technique eliminates need to drill into brain cavity. Intracranial dynamics instrument probes cranium ultrasonically to obtain data for determination of intracranial pressure (ICP) and pressure-volume index (PVI). Instrument determines sensitivity of skull to changes in pressure and by use of mechanical device to exert external calibrated pressure on skull. By monitoring volume of blood flowing into jugular vein, one determines change of volume of blood in cranial system. By measuring response of skull to increasing pressure (where pressure increased by tilting patient known amount) and by using cranial blood pressure, one determines intial pressure in cerebrospinal fluid. Once PVI determined, ICP determined.

Cantrell, John H.; Yost, William T.

1994-01-01

455

Know Your Blood Pressure Many people with diabetes also have high blood pressure.  

E-print Network

Know Your Blood Pressure Many people with diabetes also have high blood pressure. Blood pressure is to keep the second number 80 or less. If either number is too high, you have high blood pressure. The first number is the pressure when your heart pumps. #12; Most people have high blood pressure because

456

Blade Tip Pressure Measurements Using Pressure Sensitive Paint  

NASA Technical Reports Server (NTRS)

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

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

2012-01-01

457

Effect of high hydrostatic pressure and high dynamic pressure on stability and rheological properties of model oil-in-water emulsions  

Microsoft Academic Search

Both static and dynamic high pressure applications provide interesting modifications in food structures which lead to new product formulations. In this study, the effects of two different treatments, high hydrostatic pressure (HHP) and high dynamic pressure (HDP), on oil-in-water emulsions were identified and compared. Microfluidization was selected from among the HDP homogenization techniques. The performance of each process was analyzed

Erman Bigikocin; Behic Mert; Hami Alpas

2011-01-01

458

Optical pressure/density measuring means  

DOEpatents

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

Veligdan, J.T.

1995-05-09

459

Optical pressure/density measuring means  

DOEpatents

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

Veligdan, James T. (Manorville, NY)

1995-05-09

460

49 CFR 179.15 - Pressure relief devices.  

Code of Federal Regulations, 2014 CFR

...padding pressure and the lading vapor pressure at the following reference temperatures...burst pressure. (3) The vapor tight pressure of a reclosing pressure relief...transportation. (3) The vapor tight pressure and the...

2014-10-01

461

Steel pressure vessels for hydrostatic pressures to 50 kilobars.  

PubMed

Cylindrical steel pressure vessels are described that can be used for hydrostatic pressures up to 50 kilobars. Monoblock vessels of 350 maraging steel can be used to 40 kilobars and compound vessels with an inner vessel of 350 maraging steel and an outer vessel of 300 maraging steel to 50 kilobars. Neither requires the cylinder to be end loaded, and so they are much easier to use than the more usual compound vessels with a tungsten carbide inner and steel outer vessel. PMID:18699223

Lavergne, A; Whalley, E

1978-07-01

462

High-speed pressure clamp.  

PubMed

We built a high-speed, pneumatic pressure clamp to stimulate patch-clamped membranes mechanically. The key control element is a newly designed differential valve that uses a single, nickel-plated piezoelectric bending element to control both pressure and vacuum. To minimize response time, the valve body was designed with minimum dead volume. The result is improved response time and stability with a threefold decrease in actuation latency. Tight valve clearances minimize the steady-state air flow, permitting us to use small resonant-piston pumps to supply pressure and vacuum. To protect the valve from water contamination in the event of a broken pipette, an optical sensor detects water entering the valve and increases pressure rapidly to clear the system. The open-loop time constant for pressure is 2.5 ms for a 100-mmHg step, and the closed-loop settling time is 500-600 micros. Valve actuation latency is 120 micros. The system performance is illustrated for mechanically induced changes in patch capacitance. PMID:12397401

Besch, Stephen R; Suchyna, Thomas; Sachs, Frederick

2002-10-01

463

Linear ruby scale and one megabar. [high pressure fluorescence  

NASA Technical Reports Server (NTRS)

The accuracy and validity of certain techniques used in studying high-pressure transitions have been investigated. Experiments which place upper limits of about 20 GPa and about 50 GPa on pressures practically attainable using uniaxial supported opposed anvil devices with tungsten carbide pistons and uniaxial opposed flat anvil diamond devices, respectively, are reported. Direct static determinations of the transition pressures of GaP by two different methods are described. The values obtained indicate that the linear ruby scale increasingly overestimates the transition pressure as the pressure rises above 10 GPa. It is further shown that the use of shock-based marker materials, such as silver, as the basis of pressure measurement in X-ray diffraction studies leads to bulk moduli of cubic carbides which are in extreme disagreement with expected values.

Ruoff, A. L.

1979-01-01

464

Status of orifice induced pressure error studies  

NASA Technical Reports Server (NTRS)

The construction of high Reynolds number facilities, such as the National Transonic Facility (NTF) and the 0.3-m Transonic Cryogenic Tunnel (TCT), has stimulated interest again in the study of orifice induced static pressure. In a high Reynolds number facility, the orifice will have a much larger effect on the boundary layer than in a conventional wind tunnel. The present investigation was performed in the 0.3-m TCT at Mach numbers in the range from 0.60 to 0.80 and Reynolds numbers in the range from 6,000,000 to 40,000,000 with the objective to compare the porous plug orifices to conventional 0.025 cm orifices in a high Reynolds number environment. It was found that there was an error at high Reynolds numbers which could not be neglected and that the use of a porous metal disk in a conventional orifice could virtually eliminate the orifice induced pressure error.

Plentovich, E. B.

1984-01-01

465

Transformational acoustic metamaterials based on pressure gradients  

E-print Network

We apply a homogenization process to the acoustic velocity potential wave equation. The study of various examples shows that the resulting effective properties are different from those of the homogenized pressure wave equation for the same underlying acoustic parameters. A careful analysis reveals that a given set of inhomogeneous parameters represents an entirely different physical system depending on the considered equation. Our findings unveil a different way of tailoring acoustic properties through gradients of the static pressure. In contrast to standard metafluids based on isobaric composites, this alternative kind of metafluids is suitable for the implementation of transformational devices designed via the velocity potential equation. This includes acoustic systems in a moving background or arising from general space-time transformations. As an example, we design a device able to cloak the acoustic velocity potential.

C. García-Meca; S. Carloni; C. Barceló; G. Jannes; J. Sánchez-Dehesa; A. Martínez

2014-09-18

466

Dissipation of anomalous pressures in the subsurface  

NASA Astrophysics Data System (ADS)

Zones of anomalous pressure, higher and lower than hydrostatic pressure, have been observed in many sedimentary basins around the world. These normally consist of groups of pressure compartments: volumes of higher-permeability rock surrounded on all sides by lower-permeability barriers. Knowledge of the timescales over which these abnormal pressures are maintained and the mechanisms by which they dissipate is critical for understanding how fluids, such as oil and gas, move in the subsurface. Existing analytic solutions investigate pressure dissipation through low-permeability barriers on top of or underneath an isolated pressure compartment. There are no analytic solutions describing pressure dissipation through lateral barriers, such as faults, or investigating the impact of groups of pressure compartments on the rate of pressure dissipation. This paper presents simple analytic models to investigate pressure dissipation through barriers, such as faults, forming the sides of pressure compartments. The timescales are compared with a solution for pressure dissipation through barriers on top of and underneath the compartment. It also investigates analytically the rate of pressure dissipation from groups of pressure compartments. Lateral seal permeabilities of 10-19 m2 may delay pressure equilibration for millions of years provided the compartment has a sufficiently high fluid storage capacity. Factors contributing toward a high fluid storage capacity include a high fluid compressibility (as is the case in hydrocarbon reservoirs) and a high porosity. The grouping of abnormally pressured compartments into "megacompartment complexes" may delay pressure dissipation for hundreds of millions of years.

Muggeridge, Ann; Abacioglu, Yafes; England, William; Smalley, Craig

2004-11-01

467

Constant-Differential-Pressure Two-Fluid Accumulator  

NASA Technical Reports Server (NTRS)

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

Piecuch, Benjamin; Dalton, Luke T.

2010-01-01

468

Propellant combustion at low pressures  

SciTech Connect

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 proved to be poor. At low pressures, all propellants are susceptible to irregular burning: above 50 kPa oscillatory combustion was hardly observed. All propellants exhibit distinct preferred frequencies for oscillatory combustion. These frequencies, being much lower than the acoustic frequency of the test system, are associated with the combustion characteristics of the propellants. They depend strongly on the combustion pressure and the initial propellant temperature.

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

1986-03-01

469

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

470

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

471

Pressure pulsations above turbomolecular pumps  

NASA Technical Reports Server (NTRS)

Lange and Singleton (1978) have observed pressure pulses above a turbomolecular pump. They reported that the mean pulse frequency increased with the temperature of the pump cooling water and that the evolved gas was mainly hydrogen. The present investigation takes into account tests conducted with a similar pumping system. The pumping system was equipped with additional pressure-monitoring equipment in order to study these pulsations in more detail. It was found that at least two distinct types of pressure pulsations may be present in a turbomolecular-pumped ultrahigh vacuum system. The random hydrogen pulses are easily eliminated for period of days by changing the cooling water temperature. The cyclic pulses consisting mainly of water vapor are not likely to be a problem in normal experiments.

Danziger, S.; Kendall, B. R. F.; Dormer, J.

1982-01-01

472

Pressure-driven peristaltic flow  

NASA Astrophysics Data System (ADS)

The peristaltic motion of an incompressible fluid in two-dimensional channel is investigated. Instead of fixing the law of wall's coordinate variation, the law of pressure variation on the wall is fixed and the border's coordinate changes to provide the law of pressure variation on the wall. In case of small amplitude of pressure-variation on the wall A, expansion wave propagates along the length of channel and the wave results in the peristaltic transport of fluid. In the case of large A, the channel divides into two parts. The small pulsating part in the end of the tube creates the flow as a human heart, while the other big part loses this function. The solution of problem for the first peristaltic mode is stable, while the solution for the second "heart" mode is unstable and depends heavily on boundary conditions.

Mingalev, S. V.; Lyubimov, D. V.; Lyubimova, T. P.

2013-03-01

473

IIH with normal CSF pressures?  

PubMed Central

Idiopathic intracranial hypertension (IIH) is a condition of raised intracranial pressure (ICP) in the absence of space occupying lesions. ICP is usually measured by lumbar puncture and a cerebrospinal fluid (CSF) pressure above 250 mm H2O is one of the diagnostic criteria of IIH. Recently, we have encountered two patients who complained of headaches and exhibited disc swelling without an increased ICP. We prescribed acetazolamide and followed both patients frequently; because of the definite disc swelling with IIH related symptoms. Symptoms and signs resolved in both patients after they started taking acetazolamide. It is generally known that an elevated ICP, as measured by lumbar puncture, is the most important diagnostic sign of IIH. However, these cases caution even when CSF pressure is within the normal range, that suspicion should be raised when a patient has papilledema with related symptoms, since untreated papilledema may cause progressive and irreversible visual loss. PMID:24145570

Suh, Soh Youn; Kim, Seong-Joon

2013-01-01

474

Melting of ice under pressure  

PubMed Central

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 ?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

2008-01-01

475

Accuracy of Pressure Sensitive Paint  

NASA Technical Reports Server (NTRS)

Uncertainty in pressure sensitive paint (PSP) measurement is investigated from a standpoint of system modeling. A functional relation between the imaging system output and luminescent emission from PSP is obtained based on studies of radiative energy transports in PSP and photodetector response to luminescence. This relation provides insights into physical origins of various elemental error sources and allows estimate of the total PSP measurement uncertainty contributed by the elemental errors. The elemental errors and their sensitivity coefficients in the error propagation equation are evaluated. Useful formulas are given for the minimum pressure uncertainty that PSP can possibly achieve and the upper bounds of the elemental errors to meet required pressure accuracy. An instructive example of a Joukowsky airfoil in subsonic flows is given to illustrate uncertainty estimates in PSP measurements.

Liu, Tianshu; Guille, M.; Sullivan, J. P.

2001-01-01

476

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

477

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

478

High pressure proton disorder in brucite  

NASA Astrophysics Data System (ADS)

Brucite [Mg(OH)2] is one of the simplest hydrous phases and serves as a model system for complex hydrogen bearing silicates of Earth's mantle. Brucite belongs to a class of M(OH)2 compounds that appear to show unusual behavior at high pressure: the protons disorder while the MO sub-lattice remains crystalline. The nature and extent of proton disorder is uncertain. One can envision two types of proton disorder: 1) dynamic; the hydroxyl bond is tilted away from the c-axis and the proton hops between three symmetrically related potential wells or 2) static; each proton occupies a single well, and long-range order is frustrated by the hexagonal symmetry of the lattice. We explore the structure and physical properties of brucite over a wide range of pressure with density functional theory using the variable cell shape plane wave pseudopotential method in the local density (LDA) and generalized gradient (GGA) approximations. In this present study, we probe the energetics underlying the structure and dynamics of the proton sub-lattice by performing a series of constrained and unconstrained static calculations based on an energetically stable supercell wherein protons occupy 6i Wyckoff positions as opposed to 2d positions. We find that the equation of state and variation of lattice parameters of the superstructure with compression agree well with experiment. The displacement of the hydrogen from the three-fold axis (2d position) increases smoothly with increasing pressure. This means that even in the absence of dynamic disorder (i.e. at 0 K), the protons are frustrated and would be expected to exhibit long range disorder akin to a spin glass. In order to shed light on the dynamic nature of the proton hopping between the three energetically equivalent 6i sites, we have determined the activation barrier for such jumps. We find that the energy barrier increases with compression, possibly indicating a transition from dynamic proton disorder at lower pressures to static disorder at higher pressure. We have also investigated the possibility of proton jumps across the interlayer, by determining the potential energy well along the O?s\\)O vector. We infer that proton jumps across the interlayer are either strongly limited, or highly cooperative since we do not find any evidence of a double well along the O?s\\)O vector. This picture supports the view that brucite does not exhibit hydrogen bonding.

Mookherjee, M.; Stixrude, L.

2004-12-01

479

Measuring Blood Pressure in Space  

NSDL National Science Digital Library

In this activity (page 105 of the PDF), learners measure heart rate and blood pressure and learn how to obtain consistent measurements during repeated tests. This activity teaches learners how to measure a pulse manually as well as how to use the sphygmomanometer and the stethoscope. Use this activity to discuss how astronauts in space measure their blood pressure and heart rate in space differently. The lesson guide, part of NASA's "The Brain in Space: A Teacher's Guide with Activities for Neuroscience," includes background information, evaluation strategies, and handouts. Note: cost of materials does not include cost of stethoscope or sphygmomanometer; these may be borrowed from a nurse.

Macleish, Marlene Y.; Mclean, Bernice R.

2012-06-26

480

Low pressure piezoelectric valve design  

NASA Astrophysics Data System (ADS)

In this paper a ball-type valve actuated by a piezoelectric bender is studied. In this valve different parameters are adjustable allowing different operational aspects. The design procedure is economic and easy to test. Some models are developed to allow an optimization of the structure for special requirements. A prototype has been manufactured to verify the models. The measurement procedure is exposed. This design does not allow high tank pressure but, on this basis, a structure where the pressure locks the ball (reverse structure) is possible.

Bernard, Y.; Razek, A.

2012-06-01

481

SUBNANOWATT MICROBUBBLE PRESSURE TRANSDUCER C. A. Gutierrez*  

E-print Network

impedance measurement. Real-time hydrostatic pressure measurement with excellent sensitivity (-10.7 /psi, ±0 in vivo pressure sensors. Our B pressure sensing approach eliminates the need for hermetic packaging (forSUBNANOWATT MICROBUBBLE PRESSURE TRANSDUCER C. A. Gutierrez* and E. Meng University of Southern

Meng, Ellis

482

Vacuum-sealed silicon micromachined pressure sensors  

Microsoft Academic Search

Considerable progress in silicon pressure sensors has been made in recent years. This paper discusses three types of vacuum-sealed silicon micromachined pressure sensors that represent the present state of the art in this important area. The devices are a capacitive vacuum sensor, a surface-micromachined microdiaphragm pressure sensor, and a resonant pressure sensor. Vacuum sealing for these devices is accomplished using

Masayoshi Esashi; Susumu Sugiyama; Kyoichi Ikeda; YUELIN WANG; Haruzo Miyashita

1998-01-01

483

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

484

Pressure sensor based on distributed temperature sensing  

Microsoft Academic Search

A differential pressure sensor has been realized with thermal readout. The thermal readout allows simultaneous measurement of the membrane deflection due to a pressure difference and measurement of the absolute pressure by operating the structure as a Pirani pressure sensor. The measuring of the temperature distribution makes it possible to take the heat transfer to the support in to account

J. J. van Baar; R. J. Wiegerink; J. W. Berenschot; T. S. J. Lammerink; G. J. M. Krijnen; M. Elwenspoek

2002-01-01

485

Vapor Pressure Measurements in a Closed System  

ERIC Educational Resources Information Center

An alternative method that uses a simple apparatus to measure vapor pressure versus temperature in a closed system, in which the total pressure is the vapor pressure of the liquid sample, is described. The use of this apparatus gives students a more direct picture of vapor pressure than the isoteniscope method and results have generally been quite…

Iannone, Mark

2006-01-01

486

Pressure Marks Gonzalo Ramos, Ravin Balakrishnan  

E-print Network

Pressure Marks Gonzalo Ramos, Ravin Balakrishnan Department of Computer Science University, we introduce pressure marks ­ pen strokes where the varia- tions in pressure make it possible which we develop a set of four basic types of pressure marks. We first assess the viability of this set

Toronto, University of

487

Anisotropic pressure and magnetic perturbations in tokamaks  

E-print Network

1 Anisotropic pressure and magnetic perturbations in tokamaks H.E. Mynick PPPL Nov.6, 2008. -Less appreciated is that: -scalar pressure gives 0 nonambipolar , hence 0 torque, so calculations using scalar-pressure equilibria are non-self-consistent. -However, B also produces a pressure

488

High-Pressure Protein Crystallography and NMR  

E-print Network

High-Pressure Protein Crystallography and NMR to Explore Protein Conformations Marcus D. Collins,1, energy landscape, protein thermodynamics, pressure cryocooling Abstract High-pressure methods for solving's native conformation, but also the higher free energy conformations. The ability of high-pressure meth

Gruner, Sol M.

489

Stirling engine with pressurized crankcase  

DOEpatents

A two piston Stirling engine wherein the pistons are coupled to a common crankshaft via bearing means, the pistons include pad means to minimize friction between the pistons and the cylinders during reciprocation of the pistons, means for pressurizing the engine crankcase, and means for cooling the crankshaft and the bearing means eliminating the need for oil in the crankcase.

Corey, John A. (Melrose, NY)

1988-01-01

490

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

491

Pressure vessel having continuous sidewall  

NASA Technical Reports Server (NTRS)

A spacecraft pressure vessel has a tub member. A sidewall member is coupled to the tub member so that a bottom section of the sidewall member extends from an attachment intersection with the tub member and away from the tub member. The bottom section of the sidewall member receives and transfers a load through the sidewall member.

Simon, Xavier D. (Inventor); Barackman, Victor J. (Inventor)

2011-01-01

492

An Exercise in Air Pressure  

NSDL National Science Digital Library

This elementary school/middle laboratory activity requires students to watch a demonstration of air pressure changes and then answer several questions. It is part of the Atmospheric Visualization Collection (AVC), which focuses on data from the Atmospheric Radiation Measurement (ARM) program.

Carrie Talus

2003-01-01

493

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. PMID:10866977

Kharakoz, D P

2000-01-01

494

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

495

Pressure compensated flow control valve  

Microsoft Academic Search

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

Minteer; Daniel J

1999-01-01

496

MEMS Pressure Sensor Backside Etch  

NSDL National Science Digital Library

This animation, created by Southwest Center for Microsystems Education (SCME), " illustrates the anisotropic etch on the backside of a silicon wafer. The chamber formed as a result of this etch is used as the reference chamber for a micro-pressure sensor." Viewers can find supporting Learning Modules and activities from the SCME website under Educational Materials.

2014-07-21

497

History of Physical Terms: "Pressure"  

ERIC Educational Resources Information Center

Scientific terms drawn from common language are often charged with suggestions that may even be inconsistent with their restricted scientific meaning, thus posing didactic problems. The (non-linear) historical journey of the word "pressure" is illustrated here through original quotations from Stevinus, Torricelli, Pascal, Boyle,…

Frontali, Clara

2013-01-01

498

Geometry attained by pressurized membranes  

Microsoft Academic Search

An intensive investigation has been carried out to study the surface profiles obtained as a result of the large deformations of pressurized membranes. The study shows that the inflated membrane shapes may have the requisite surface accuracy for use in future large space apertures. Both analytical and experimental work have been carried out. On the analytical side, the classical work

Arthur Palisoc; Gordon Veal; Constantine Cassapakis; Gyula Greschik; Martin Mikulas

1998-01-01

499

High-pressure water facility  

NASA Technical Reports Server (NTRS)

NASA Test Operations Group employees, from left, Todd Pearson, Tim Delcuze and Rodney Wilkinson maintain a water pump in Stennis Space Center's high-pressure water facility. The three were part of a group of employees who rode out Hurricane Katrina at the facility and helped protect NASA's rocket engine test complex.

2006-01-01

500

Research study of pressure instrumentation  

NASA Technical Reports Server (NTRS)

To obtain a more vibration resistant pressure sensor for use on the Space Shuttle Main Engine, a proximity probe based, diaphragm type pressure sensor breadboard was developed. A fiber optic proximity probe was selected as the sensor. In combination with existing electronics, a thermal stability evaluation of the entire probe system was made. Based upon the results, a breadboard design of the pressure sensor and electronics was made and fabricated. A brief series of functional experiments was made with the breadboard to calibrate, thermally compensate, and linearize its response. In these experiments, the performance obtained in the temperature range of -320 F (liquid N2) to +200 F was comparable to that of the strain gage based sensor presently in use on the engine. In tests at NASA-Marshall Space Flight Center (MSFC), after some time at or near liquid nitrogen temperatures, the sensor output varied over the entire output range. These large spurious signals were attributed to condensation of air in the sensing gap. In the next phase of development of this sensor, an evaluation of fabrication techniques toward greater thermal and mechanical stability of the fiber probe assembly must be made. In addition to this, a positive optics to metal seal must be developed to withstand the pressure that would result from a diaphragm failure.

Hoogenboom, L.; Hull-Allen, G.

1984-01-01