Sample records for pressure static pressure

  1. Measurement of static pressure on aircraft

    NASA Technical Reports Server (NTRS)

    Gracey, William

    1958-01-01

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

  2. 30 CFR 18.67 - Static-pressure tests.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...Tests § 18.67 Static-pressure tests. Static-pressure tests shall be conducted...will not reveal defects in castings or in single-seam welds...will be conducted. The static pressure to be applied shall be...

  3. 30 CFR 18.67 - Static-pressure tests.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...Tests § 18.67 Static-pressure tests. Static-pressure tests shall be conducted...will not reveal defects in castings or in single-seam welds...will be conducted. The static pressure to be applied shall be...

  4. 30 CFR 18.67 - Static-pressure tests.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...Tests § 18.67 Static-pressure tests. Static-pressure tests shall be conducted...will not reveal defects in castings or in single-seam welds...will be conducted. The static pressure to be applied shall be...

  5. 30 CFR 18.67 - Static-pressure tests.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...Tests § 18.67 Static-pressure tests. Static-pressure tests shall be conducted...will not reveal defects in castings or in single-seam welds...will be conducted. The static pressure to be applied shall be...

  6. 30 CFR 18.67 - Static-pressure tests.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...Tests § 18.67 Static-pressure tests. Static-pressure tests shall be conducted...will not reveal defects in castings or in single-seam welds...will be conducted. The static pressure to be applied shall be...

  7. 14 CFR 27.1325 - Static pressure systems.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ...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...

  8. 14 CFR 27.1325 - Static pressure systems.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ...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...

  9. 14 CFR 27.1325 - Static pressure systems.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ...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...

  10. 14 CFR 27.1325 - Static pressure systems.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ...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...

  11. 14 CFR 27.1325 - Static pressure systems.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ...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...

  12. 14 CFR 23.1325 - Static pressure system.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ...the static pressure system until a pressure differential equivalent to the maximum cabin pressure differential for which the airplane...equivalent altitude of the maximum cabin differential pressure or 100 feet, whichever is...

  13. 14 CFR 23.1325 - Static pressure system.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ...the static pressure system until a pressure differential equivalent to the maximum cabin pressure differential for which the airplane...equivalent altitude of the maximum cabin differential pressure or 100 feet, whichever is...

  14. 14 CFR 23.1325 - Static pressure system.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ...the static pressure system until a pressure differential equivalent to the maximum cabin pressure differential for which the airplane...equivalent altitude of the maximum cabin differential pressure or 100 feet, whichever is...

  15. 14 CFR 25.1325 - Static pressure systems.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ...the static pressure system until a pressure differential equivalent to the maximum cabin pressure differential for which the airplane...equivalent altitude of the maximum cabin differential pressure or 100 feet, whichever is...

  16. 14 CFR 25.1325 - Static pressure systems.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ...the static pressure system until a pressure differential equivalent to the maximum cabin pressure differential for which the airplane...equivalent altitude of the maximum cabin differential pressure or 100 feet, whichever is...

  17. 14 CFR 23.1325 - Static pressure system.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ...the static pressure system until a pressure differential equivalent to the maximum cabin pressure differential for which the airplane...equivalent altitude of the maximum cabin differential pressure or 100 feet, whichever is...

  18. 14 CFR 25.1325 - Static pressure systems.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ...the static pressure system until a pressure differential equivalent to the maximum cabin pressure differential for which the airplane...equivalent altitude of the maximum cabin differential pressure or 100 feet, whichever is...

  19. 14 CFR 25.1325 - Static pressure systems.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ...the static pressure system until a pressure differential equivalent to the maximum cabin pressure differential for which the airplane...equivalent altitude of the maximum cabin differential pressure or 100 feet, whichever is...

  20. 14 CFR 23.1325 - Static pressure system.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ...the static pressure system until a pressure differential equivalent to the maximum cabin pressure differential for which the airplane...equivalent altitude of the maximum cabin differential pressure or 100 feet, whichever is...

  1. 14 CFR 25.1325 - Static pressure systems.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ...the static pressure system until a pressure differential equivalent to the maximum cabin pressure differential for which the airplane...equivalent altitude of the maximum cabin differential pressure or 100 feet, whichever is...

  2. 14 CFR 29.1325 - Static pressure and pressure altimeter systems.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ...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...

  3. 14 CFR 29.1325 - Static pressure and pressure altimeter systems.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ...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...

  4. 14 CFR 29.1325 - Static pressure and pressure altimeter systems.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ...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...

  5. 14 CFR 29.1325 - Static pressure and pressure altimeter systems.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ...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...

  6. 14 CFR 29.1325 - Static pressure and pressure altimeter systems.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ...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...

  7. Martian Atmospheric Pressure Static Charge Elimination Tool

    NASA Technical Reports Server (NTRS)

    Johansen, Michael R.

    2014-01-01

    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.

  8. 14 CFR 33.64 - Pressurized engine static parts.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ...2010-01-01 false Pressurized engine static parts. 33.64 Section 33.64 ...Engines § 33.64 Pressurized engine static parts. (a) Strength. The applicant...analysis, or a combination of both, that all static parts subject to significant gas or...

  9. 30 CFR 7.104 - Internal static pressure test.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...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)...

  10. 30 CFR 7.307 - Static pressure test.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...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...

  11. Pressure

    NSDL National Science Digital Library

    Wolfgang Christian

    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.

  12. 30 CFR 250.1153 - When must I conduct a static bottomhole pressure survey?

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...2010-07-01 false When must I conduct a static bottomhole pressure survey? 250.1153... § 250.1153 When must I conduct a static bottomhole pressure survey? (a) You must conduct a static bottomhole pressure survey under the...

  13. Intrinsic PEEP on static pressure-volume curves

    Microsoft Academic Search

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

    1990-01-01

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

  14. Portable dynamic pressure generator for static and dynamic calibration of in situ pressure transducers

    NASA Technical Reports Server (NTRS)

    Bolt, P. A.; Hess, R. W.; Davis, W. T.

    1983-01-01

    A portable dynamic pressure generator was developed to meet the requirements of determining the dynamic sensitivities of in situ pressure transducers at low frequencies. The device is designed to operate in a frequency range of 0 to 100 Hz, although it was only tested up to 30 Hz, and to generate dynamic pressures up to 13.8 kPa (2 psi). A description of the operating characteristics and instrumentation used for pressure, frequency, and displacement measurements is given. The pressure generator was used to statically and dynamically calibrate transducers. Test results demonstrated that a difference an exist between the static and dynamic sensitivity of a transducer, confirming the need for dynamic calibrations of in situ pressure transducers.

  15. Measurement of static and dynamic pulmonary work during pressure breathing.

    PubMed

    Morrison, J B; Taylor, N A

    1990-09-01

    Various environments alter static and flow-resistive pulmonary mechanics. Of interest to diving physiologists is the negative pressure breathing induced during upright immersions without appropriate modification of air supply pressure. This paper outlines methodologic considerations for determining static and flow-resistive pulmonary work under such exposures. Ten males performed inspiratory pressure-volume relaxation maneuvers and spontaneous breathing in air, and during upright immersion with mouth pressure air supply. The immersed lung centroid pressure (PLC) was +1.19 kPa relative to the hydrostatic pressure at the sternal notch. Immersion elevated inspiratory static work from 0.36 to 1.74 J.liter-1 (P less than 0.05). Pulmonary flow-resistive work was elevated from 0.20 to 0.75 J.liter-1 (P less than 0.05), whereas pulmonary resistance, determined at 0.5 liter.sec-1, increased from 0.18 to 0.44 kPa.liter-1.sec (P less than 0.05). No significant changes in the iso-volume compliance of the lung tissue, chest wall, or total respiratory system were observed (P greater than 0.05). Results indicate that increases in the work of breathing are due to a combination of hydrostatic pressure imbalance, increased pulmonary resistance, and reduced end-expiratory total respiratory compliance. PMID:2219553

  16. Static pressure and temperature compensated wideband fiber laser hydrophone

    NASA Astrophysics Data System (ADS)

    Launay, F.-X.; Lardat, R.; Bouffaron, R.; Roux, G.; Doisy, M.; Bergogne, C.

    2013-05-01

    Sensitive optical hydrophone is a key component for the design of compact fully optical acoustic arrays and one major issue about this kind of sensors is their sensitivity to hydrostatic pressure and temperature. We present in this paper a compact hydrophone which is optimized for reduced temperature sensitivity and high static pressure capability. High acoustic sensitivity is obtained through wideband mechanical amplification design. Two mock-ups have been realized and the measurements show good agreements with finite-element model. We present acoustic measurements as well as measurements in environmental conditions (temperature and pressure) obtained with a low noise opto-electronic interrogation system.

  17. Blood pressure response to low level static contractions

    Microsoft Academic Search

    Nils Fallentin I; Kurt Jørgensen

    1992-01-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2012-05-01

    Geometric altitude data from a combined Global Navigation Satellite System (GNSS) and inertial measurement unit (IMU) system on the University of Wyoming King Air research aircraft are used to estimate acceleration effects on static pressure measurement. Using data collected during periods of accelerated flight, comparison of measured pressure with that derived from GNSS/IMU geometric altitude show that errors exceeding 150 Pa can occur which is significant in airspeed and atmospheric air motion determination. A method is developed to predict static pressure errors from analysis of differential pressure measurements from a Rosemount model 858 differential pressure air velocity probe. The method was evaluated with a carefully designed probe towed on connecting tubing behind the aircraft - a "trailing cone" - in steady flight, and shown to have a precision of about ±10 Pa over a wide range of conditions including various altitudes, power settings, and gear and flap extensions. Under accelerated flight conditions, compared to the GNSS/IMU data, this algorithm predicts corrections to a precision of better than ±20 Pa. Some limiting factors affecting the precision of static pressure measurement on a research aircraft are examined.

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

    NASA Astrophysics Data System (ADS)

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

    2012-11-01

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

  20. Radio jet refraction in galactic atmospheres with static pressure gradients

    NASA Technical Reports Server (NTRS)

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

    1981-01-01

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

  1. 30 CFR 7.307 - Static pressure test.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...a minimum of 150 psig and the pressure maintained for a minimum of 10 seconds. (2) Following the pressure hold, the pressure shall be removed and the pressurizing...i) Leakage through welds or casting; or (ii) Rupture of...

  2. 30 CFR 7.307 - Static pressure test.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...a minimum of 150 psig and the pressure maintained for a minimum of 10 seconds. (2) Following the pressure hold, the pressure shall be removed and the pressurizing...i) Leakage through welds or casting; or (ii) Rupture of...

  3. 30 CFR 7.307 - Static pressure test.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...a minimum of 150 psig and the pressure maintained for a minimum of 10 seconds. (2) Following the pressure hold, the pressure shall be removed and the pressurizing...i) Leakage through welds or casting; or (ii) Rupture of...

  4. 30 CFR 7.307 - Static pressure test.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...a minimum of 150 psig and the pressure maintained for a minimum of 10 seconds. (2) Following the pressure hold, the pressure shall be removed and the pressurizing...i) Leakage through welds or casting; or (ii) Rupture of...

  5. Static pressure sensitivity amplification in interferometric fiber-optic hydrophones.

    PubMed

    Hughes, R; Jarzynski, J

    1980-01-01

    The induced optical phase change produced when a static pressure is applied to the test arm of an interferometric single-mode fiber optic hydrophone is examined in terms of hydrostatic and radial mechanical models. The expressions for the models are given in terms of a 3-D solution to the equations of elastostatics for multilayered cylinders. The induced phase change is calculated using both models for various values of the diameter and elastic properties of fiber jacket materials. It is shown that the phase change predicted from the 3-D approach for each model can be adequately described in terms of much simpler 2-D plane strain models. Calculations show that the hydrophone sensitivity of a jacketed fiber is amplified compared with a bare fiber. The largest increase in sensitivity is predicted with the radial model. Calculated sensitivities for the hydrostatic model are shown to correspond closely in value with static pressure sensitivity measurements for the experimental arrangement used here. PMID:20216800

  6. 33 CFR 183.580 - Static pressure test for fuel tanks.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...2013-07-01 false Static pressure test for fuel tanks. 183.580...GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) BOATING SAFETY...ASSOCIATED EQUIPMENT Fuel Systems Tests § 183.580 Static pressure test for fuel tanks. A...

  7. 33 CFR 183.580 - Static pressure test for fuel tanks.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...2014-07-01 false Static pressure test for fuel tanks. 183.580...GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) BOATING SAFETY...ASSOCIATED EQUIPMENT Fuel Systems Tests § 183.580 Static pressure test for fuel tanks. A...

  8. 33 CFR 183.580 - Static pressure test for fuel tanks.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...2011-07-01 false Static pressure test for fuel tanks. 183.580...GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) BOATING SAFETY...ASSOCIATED EQUIPMENT Fuel Systems Tests § 183.580 Static pressure test for fuel tanks. A...

  9. 33 CFR 183.580 - Static pressure test for fuel tanks.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...2012-07-01 false Static pressure test for fuel tanks. 183.580...GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) BOATING SAFETY...ASSOCIATED EQUIPMENT Fuel Systems Tests § 183.580 Static pressure test for fuel tanks. A...

  10. Plume diagnostics of SRM static firings for pressure perturbation studies

    NASA Technical Reports Server (NTRS)

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

    1995-01-01

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

  11. Electrical conductivity measurement of iron at high static pressure

    NASA Astrophysics Data System (ADS)

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

    2010-12-01

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

  12. New findings in static high-pressure science

    SciTech Connect

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

    2010-11-16

    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.

  13. Uncertainty of Five-Hole Probe Measurements. [of total flow pressure, static pressure, and flow

    NASA Technical Reports Server (NTRS)

    Reichert, Bruce A.; Wendt, Bruce J.

    1994-01-01

    A new algorithm for five-hole probe calibration and data reduction using a non-nulling technique was developed, verified, and reported earlier (Wendt and Reichert, 1993). The new algorithm's simplicity permits an analytical treatment of the propagation of uncertainty in five-hole probe measurement. The objectives of the uncertainty analysis are to quantify the uncertainty of five-hole probe results (e.g., total pressure, static pressure, and flow direction) and to determine the dependence of the result uncertainty on the uncertainty of all underlying experimental and calibration measurands. This study outlines a general procedure that other researchers may use to determine five-hole probe result uncertainty and provides guidance for improving the measurement technique.

  14. Hot Film Static-Pressure Probe for Flow-Field Surveys

    NASA Technical Reports Server (NTRS)

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

    1982-01-01

    New hot film static pressure probe significantly reduces response time in flow-field surveys during wind-tunnel tests. Probe incorporates two hot film sensors, unheated film for temperature compensation and heated film for pressure measurement, and sonic orifice for flow control. Hot film prove measures static pressure while compensating for gas temperature.

  15. Radio jet refraction in galactic atmospheres with static pressure gradients

    NASA Technical Reports Server (NTRS)

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

    1981-01-01

    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.

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

    PubMed Central

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

    2004-01-01

    The purpose of this paper is to determine the static and dynamic rupture pressures of 20 human and 20 porcine eyes. This study found the static test results show an average rupture pressure for porcine eyes of 1.00 ± 0.18 MPa while the average rupture pressure for human eyes was 0.36 ± 0.20 MPa. For dynamic loading, the average porcine rupture pressure was 1.64 ± 0.32 MPa, and the average rupture pressure for human eyes was 0.91 ± 0.29 MPa. Significant differences are found between average rupture pressures from all four groups of tests (p = 0.01). A risk function has been developed and predicts a 50% risk of globe rupture at 1.02 MPa, 1.66 MPa, 0.35 MPa, and 0.90 MPa internal pressure for porcine static, porcine dynamic, human static, and human dynamic loading conditions, respectively. PMID:15319124

  17. Combined Bridgman and O-Ring Static Pressure Seal

    Microsoft Academic Search

    1960-01-01

    tially square in cross section, resting on a conical portion of the plug. The O-ring provides the initial pressure seal, but when the pressure reaches a sufficient level the last ring starts to flow against the shoulder, giving the usual type of unsupported area seal. The last ring has taken over the sealing job before the O-ring fails. This seal

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

    E-print Network

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

    1996-01-01

    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...

  19. 33 CFR 183.580 - Static pressure test for fuel tanks.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...Navigable Waters 2 2010-07-01 2010-07-01 false Static pressure test for fuel tanks. 183.580 Section 183.580...ASSOCIATED EQUIPMENT Fuel Systems Tests § 183.580 Static pressure test for fuel tanks. A fuel tank is tested...

  20. A novel tubular superconductor stabilized with static pressurized helium

    SciTech Connect

    Lvovsky, Y.M.; Kral, S.F.; Rackov, P.M. [Babcock and Wilcox, Lynchburg, VA (United States)] [Babcock and Wilcox, Lynchburg, VA (United States)

    1994-07-01

    A new superconductor concept for encapsulated, medium-size magnets with a significantly increased stability margin is presented. A tubular superconductor (TSC) of a few millimeters outer diameter is drawn from a billet (normal metal + superconducting inserts). After winding, the TSC is filled with static gaseous helium under pressure, which serves as an enthalpy stabilizer. The approach is beneficial both for NbTi and Nb{sub 3}Sn magnets, including conductively cooled magnets. For example, Nb{sub 3}Sn TSC magnet for 8 T, 8 K operation has a stability margin up to 8 times greater than a corresponding magnet using a conventional conductor. The stability margin against slow (steady-state) and transient disturbances has been analyzed for TSC and cable-in-conduit conductors (CICC). Analytical expressions for the stability margin have been obtained and optimal helium cross-section have been determined. Results can be used to design helium-filled conductors for magnets operating to maximum stability margin.

  1. Flight evaluation of an engine static pressure noseprobe in an F-15 airplane

    NASA Technical Reports Server (NTRS)

    Foote, C. H.; Jaekel, R. F.

    1981-01-01

    The flight testing of an inlet static pressure probe and instrumented inlet case produced results consistent with sea-level and altitude stand testing. The F-15 flight test verified the basic relationship of total to static pressure ratio versus corrected airflow and automatic distortion downmatch with the engine pressure ratio control mode. Additionally, the backup control inlet case statics demonstrated sufficient accuracy for backup control fuel flow scheduling, and the station 6 manifolded production probe was in agreement with the flight test station 6 tota pressure probes.

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

    Microsoft Academic Search

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

    2008-01-01

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

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

    E-print Network

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

    2007-01-01

    Optimization of the static pressure reset is always critical in the pursuit of maximum savings of fan power and thermal energy consumption in a VAV system. This paper theoretically investigated three static pressure reset methods, i.e. VAV terminal...

  4. An Investigation of Alternative Methods for Measuring Static Pressure of Unitary Air Conditioners and Heat Pumps

    E-print Network

    Wheeler, Grant Benson

    2013-08-12

    This project was created to address an important issue currently faced by test facilities measuring static pressure for air-conditioning and heat pumps. Specifically, ASHRAE Standard 37, the industry standard for test setup, requires an outlet duct...

  5. Static Pressure Losses in 6 in., 8 in., and 10 in. Nonmetallic Flexible Duct (RP-1333)

    E-print Network

    Weaver, K.; Culp, C.H.

    Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. Static Pressure Losses in Nonmetallic Flexible Duct Weaver, Kevin;Culp, Charles ASHRAE Transactions; 2007; 113, ProQuest pg. 400 Reproduced...

  6. An Investigation of Alternative Methods for Measuring Static Pressure of Unitary Air Conditioners and Heat Pumps 

    E-print Network

    Wheeler, Grant Benson

    2013-08-12

    This project was created to address an important issue currently faced by test facilities measuring static pressure for air-conditioning and heat pumps. Specifically, ASHRAE Standard 37, the industry standard for test setup, requires an outlet duct...

  7. Static Pressure Losses in 6 in., 8 in., and 10 in. Nonmetallic Flexible Duct (RP-1333) 

    E-print Network

    Weaver, K.; Culp, C.H.

    2007-01-01

    Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. Static Pressure Losses in Nonmetallic Flexible Duct Weaver, Kevin;Culp, Charles ASHRAE Transactions; 2007; 113, ProQuest pg. 400 Reproduced...

  8. Hot-film static-pressure probe for surveying flow fields

    NASA Technical Reports Server (NTRS)

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

    1981-01-01

    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.

  9. Polymerization of formic acid under high static pressure

    NASA Astrophysics Data System (ADS)

    Goncharov, A. F.; Manaa, M. R.; Zaug, J. M.; Fried, L. E.; Montgomery, W.

    2004-03-01

    We report the results of Raman and x-ray diffraction measurements in diamond anvil cell to 45 GPa and quantum molecular dynamic simulations to 70 GPa. Raman spectra and x-ray diffraction patterns indicate major changes at about 40 GPa with a large hysteresis at decompression. In contrast to the low-P solid, no lattice modes are observed in the Raman spectrum of a high-pressure phase; a few broad bands that are recorded correspond to C-H and C-O bonds. Below the transition, X-ray diffraction patterns are consistent with Pna21 space group; the pressure dependence of the lattice constants and the unit cell volume are determined. Theoretical calculations are in agreement and indicate the proximity of the intra- and intermolecular O-H distances above 30 GPa, which suggest the symmetrization of hydrogen bond under compression. We conjecture that the structure of the high-pressure formic acid consists of infinite polymeric chains; the significant decrease in intensity of x-ray diffraction pattern may indicate a partial loss of the long-range order.

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

    NASA Technical Reports Server (NTRS)

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

    1987-01-01

    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.

  11. Static pressure distribution in an angular channel with helicoidal wire

    NASA Astrophysics Data System (ADS)

    Delemos, Marcelo J. S.

    1988-12-01

    This work reports data on pressure drop distribution along a channel formed by a wire-wrapped rod placed inside a circular tube. This geometry simulates the flow field in the vicinity of a tropical fuel rod of a LMFBR (Liquid-Metal Fast Breeder Reactor) fuel assembly. The working fluid was air and the range for the Reynolds number extended from 2.26 x 10(4) to 4.52 x 10(4). The aspect ratio, P/D and the lead-to-diameter ratio, 1/D, were 1.2 and 15, respectively.

  12. Static pressure measurements in A 30 kWe class arcjet

    NASA Technical Reports Server (NTRS)

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

    1991-01-01

    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.

  13. Study on Mechanism of Aerodynamic Sound Generation by Flow Visualization and Fluctuating Static Pressure Measurements

    NASA Astrophysics Data System (ADS)

    Hiramoto, Riho; Toyoda, Kuniaki; Sato, Kotaro

    Flow visualization, particle image velocimetry (PIV), and fluctuating static pressure measurements were carried out simultaneously in a turbulent shear flow separated from a sharp-edged fence to estimate the probable location of the sound source that is closely related to vortex motion and aerodynamic sound generation. The measurement of the fluctuating static pressure is an effective way to detect vortices from pressure drops and the sound source term of the dilatation theory proposed by Ribner, which is a double time derivative of the fluctuating static pressure. Therefore, in this study, attempts were made to find the relationship between variations in the waveforms of the fluctuating static pressure, sound source term, and vortex motions obtained from the flow visualization and PIV measurements. From the results, it was revealed that pressure drops deduced from the waveforms agreed with the visualized vortices, and the waveform of the sound source term was almost the same as that of the aerodynamic sound. The results suggest that this simultaneous measurement method is useful for determining the mechanism of aerodynamic sound generation.

  14. Impacts of Static Pressure Reset on VAV System Air Leakage, Fan Power and Thermal Energy - Part I: Theoretical Model and Simulation

    E-print Network

    Liu, M.; Feng, J.; Wang, Z.; Wu, L.; Zheng, K.; Pang, W.

    2007-01-01

    As for a variable air volume (VAV) system, the air duct static pressure is a typical control variable maintained by modulating supply fan speed. The static pressure equals to the summation of the duct pressure loss downstream of the sensor...

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

    E-print Network

    Sarker, Arunava

    1993-01-01

    of mmittee) Robert E. DeOtte (Member) James C. Holste (Member) g&~ W. L. Bradley (Head of Department) August 1993 ABSTRACT Effects of Geometric Scaling on Static Pressure Measurements in Orifice Flow-meters. (August 1993) Arunava Sarker, B. E... of the flange tap in typical orifice meters on pipes of different sizes. This was accomplished by comparing the static pressure distribution in a 60. 96 cm (2 foot) diameter orifice run to that on a 5. 08 cm (2 inch) diameter orifice run using air...

  16. Measurements of Mean Static Pressure and Far Field Acoustics of Shock Containing Supersonic Jets

    NASA Technical Reports Server (NTRS)

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

    1982-01-01

    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.

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

    NASA Astrophysics Data System (ADS)

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

    1982-09-01

    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.

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

    SciTech Connect

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

    1980-07-01

    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.

  19. Radial forces in a centrifugal compressor; Experimental investigation by using magnetic bearings and static pressure distribution

    NASA Astrophysics Data System (ADS)

    Reunanen, Arttu; Larjola, Jaakko

    2005-03-01

    The volute of a centrifugal compressor causes a non-uniform pressure distribution which leads to a radial force on the impeller. This force was measured using magnetic bearings. In addition, the radial force was estimated using the static pressure distribution measured at the impeller outlet. The impeller force was found to be the highest at choke, the lowest at the design flow and moderate at stall. The radial force determined from the pressure measurements was only slightly different from the force obtained from the bearing measurements. The rotational speed was seen to affect the force to some extent.

  20. Muscle tissue oxygenation, pressure, electrical, and mechanical responses during dynamic and static voluntary contractions

    Microsoft Academic Search

    Pernille Vedsted; Anne Katrine Blangsted; Karen Søgaard; Claudio Orizio; Gisela Sjøgaard

    2006-01-01

    Dynamic muscle contractions have been shown to cause greater energy turnover and fatigue than static contractions performed\\u000a at a corresponding force level. Therefore, we hypothesized that: (1) electro- (EMG) and mechanomyography (MMG), intramuscular\\u000a pressure (IMP), and reduction in muscle oxygen tension (rTO2) would be larger during dynamic (DYN) than intermittent static (IST) low force contractions; and that (2) oxygen tension

  1. Influence of increased static pressure in MHD-channel of hypervelocity wind tunnel on its characteristics

    SciTech Connect

    Alfyorov, V.I.; Rudakova, A.P.; Rukavets, V.P.; Shcherbakov, G.I. [Central Aerohydrodynamic Institute (TsAGI), Zhukovsky (Russian Federation)

    1995-12-31

    One of the main weaknesses of available MHD gas acceleration wind tunnels which restricts their application for simulating vehicle re-entry flights and reproducing scramjet combustion chamber conditions is a relatively low static pressure in the channel (P{approximately}0.1 to 0.2 Atm). The possibility of increasing this pressure and the influence of the increased pressure on the MHD-accelerator characteristics are the subject of the present paper. It is shown that the main challenge is the necessity of increasing the total Lorentz force proportionally to the channel gas density at electrode current density not resulting in heat and electrical breakdown and the development of the side walls and interelectrode insulators designed for higher heat fluxes, q {approximately} 5 to 10 kw/cm{sup 2}. Some possible wall design versions are suggested. The influence of increased pressure is investigated using the Faraday - type MED channel at static pressures in the MHD channel from 0.2 to 1.0 Atm and total accelerating current I = 300 to 1,100 Amps when B=2.5T. Forty five electrodes are used in the MHD channel at maximum current density of 50 A/cm{sup 2}. The channel flow is calculated by applying the model of a gas in thermodynamic equilibrium. The influence of the increased pressure on electrodynamic (accelerator electrode voltages and currents, Hall voltage and current) and gasdynamic (distributions of static pressure, temperature, velocity, Mach numbers, etc., along the channel length) characteristics is evaluated. Some recommendations on the development of MHD channels for hypersonic wind tunnels designed for high pressure are suggested.

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

    E-print Network

    Weaver, K.; Culp, C.

    2006-01-01

    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...

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

    PubMed

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

    2013-09-24

    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

  4. Boundary layer transition determination for periodic and static flows using phase-averaged pressure data

    NASA Astrophysics Data System (ADS)

    Gardner, A. D.; Richter, K.

    2015-06-01

    A method of boundary layer transition measurement is presented for wind tunnel models instrumented with surface pressure taps. The measurement relies on taking a number of theoretically identical measurements at different times and then analysing the standard deviation of the pressures. Due to the slight unsteady movement of the transition position, a peak in the standard deviation of pressure is found at the transition position, and this is correlated with measurements of the transition position with an infrared camera and hot-film anemometers. In contrast to microphone measurements, it is shown that the transition detection works for data which have been low-pass filtered with a cut-off of 1 Hz. The application to static and dynamic transition measurements on static and periodically pitching helicopter rotor blade airfoils at Mach 0.3-0.5 is demonstrated.

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

    NASA Technical Reports Server (NTRS)

    Mueller, A. W.

    1984-01-01

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

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

    E-print Network

    Katul, Gabriel

    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

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

    NASA Technical Reports Server (NTRS)

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

    1985-01-01

    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.

  8. A combined theoretical and experimental investigation of uranium dioxide under high static pressure

    NASA Astrophysics Data System (ADS)

    Crowhurst, J. C.; Jeffries, J. R.; Åberg, D.; Zaug, J. M.; Dai, Z. R.; Siekhaus, W. J.; Teslich, N. E.; Holliday, K. S.; Knight, K. B.; Nelson, A. J.; Hutcheon, I. D.

    2015-07-01

    We have investigated the behavior of uranium dioxide (UO2) under high static pressure using a combination of experimental and theoretical techniques. We have made Raman spectroscopic measurements up to 87 GPa, electrical transport measurements up to 50 GPa from 10 K to room temperature, and optical transmission measurements up to 28 GPa. We have also carried out theoretical calculations within the GGA + U framework. We find that Raman frequencies match to a large extent, theoretical predictions for the cotunnite (Pnma) structure above 30 GPa, but at higher pressures some behavior is not captured theoretically. The Raman measurements also imply that the low-pressure fluorite phase coexists with the cotunnite phase up to high pressures, consistent with earlier reports. Electrical transport measurements show that the resistivity decreases by more than six orders of magnitude with increasing pressure up to 50 GPa but that the material never adopts archetypal metallic behavior. Optical transmission spectra show that while UO2 becomes increasingly opaque with increasing pressure, a likely direct optical band gap of more than 1 eV exists up to at least 28 GPa. Together with the electrical transport measurements, we conclude that the high pressure electrical conductivity of UO2 is mediated by variable-range hopping.

  9. A combined theoretical and experimental investigation of uranium dioxide under high static pressure.

    PubMed

    Crowhurst, J C; Jeffries, J R; Åberg, D; Zaug, J M; Dai, Z R; Siekhaus, W J; Teslich, N E; Holliday, K S; Knight, K B; Nelson, A J; Hutcheon, I D

    2015-07-01

    We have investigated the behavior of uranium dioxide (UO2) under high static pressure using a combination of experimental and theoretical techniques. We have made Raman spectroscopic measurements up to 87 GPa, electrical transport measurements up to 50 GPa from 10 K to room temperature, and optical transmission measurements up to 28 GPa. We have also carried out theoretical calculations within the GGA + U framework. We find that Raman frequencies match to a large extent, theoretical predictions for the cotunnite (Pnma) structure above 30 GPa, but at higher pressures some behavior is not captured theoretically. The Raman measurements also imply that the low-pressure fluorite phase coexists with the cotunnite phase up to high pressures, consistent with earlier reports. Electrical transport measurements show that the resistivity decreases by more than six orders of magnitude with increasing pressure up to 50 GPa but that the material never adopts archetypal metallic behavior. Optical transmission spectra show that while UO2 becomes increasingly opaque with increasing pressure, a likely direct optical band gap of more than 1 eV exists up to at least 28 GPa. Together with the electrical transport measurements, we conclude that the high pressure electrical conductivity of UO2 is mediated by variable-range hopping. PMID:26053594

  10. Role of potassium in the reflex regulation of blood pressure during static exercise in man.

    PubMed Central

    Fallentin, N; Jensen, B R; Byström, S; Sjøgaard, G

    1992-01-01

    1. The relationship between [K+] in venous effluent blood and alterations in mean arterial blood pressure was studied during static handgrip contractions at 15 and 30% of maximal voluntary contraction (MVC). 2. To further elucidate the importance of K+ in the reflex regulation of blood pressure a situation with normal recovery was compared with a situation in which 3 min of post-exercise occlusion was applied by arresting the circulation to the forearm just prior to the cessation of the contraction. 3. There was a temporal as well as quantitative correlation between venous [K+] and the blood pressure response during and after static exercise. During 30% MVC mean arterial blood pressure (MAP) attained 161.7 mmHg and venous [K+] 5.8 mM, while the corresponding values during 15% MVC were 121.5 mmHg and 5.0 mM. 4. In the occlusion period mean arterial blood pressure remained elevated above resting level and provided a measure of the magnitude of muscle chemoreflexes. In the same period venous [K+] was maintained at 5.3 mM and 4.6 mM following 30% MVC and 15% MVC respectively. This is indicative of interstitial concentrations of above 8-10 mM. This level is sufficiently high to stimulate type III and IV muscle afferents involved in the reflex regulation of blood pressure, and strengthens the notion that K+ may play an important role in eliciting the pressor reflex. 5. In contrast to [K+] the time course of venous blood concentrations of lactate and ammonia (NH3) exhibited a clear dissociation from the blood pressure recordings. PMID:1403829

  11. A quasi-static phase-field approach to pressurized fractures

    NASA Astrophysics Data System (ADS)

    Mikeli?, Andro; Wheeler, Mary F.; Wick, Thomas

    2015-05-01

    In this paper we present a quasi-static formulation of a phase-field model for a pressurized crack in a poroelastic medium. The mathematical model represents a linear elasticity system with a fading Gassman tensor as the crack grows, that is coupled with a variational inequality for the phase-field variable containing an entropy inequality. We introduce a novel incremental approximation that decouples displacement and phase-field problems. We establish convergence to a solution of the quasi-static problem, including Rice's condition, when the time discretization step goes to zero. Numerical experiments confirm the robustness and efficiency of this approach for multidimensional test cases.

  12. Variation with Mach Number of Static and Total Pressures Through Various Screens

    NASA Technical Reports Server (NTRS)

    Adler, Alfred A

    1946-01-01

    Tests were conducted in the Langley 24-inch highspeed tunnel to ascertain the static-pressure and total-pressure losses through screens ranging in mesh from 3 to 12 wires per inch and in wire diameter from 0.023 to 0.041 inch. Data were obtained from a Mach number of approximately 0.20 up to the maximum (choking) Mach number obtainable for each screen. The results of this investigation indicate that the pressure losses increase with increasing Mach number until the choking Mach number, which can be computed, is reached. Since choking imposes a restriction on the mass rate of flow and maximum losses are incurred at this condition, great care must be taken in selecting the screen mesh and wire dimmeter for an installation so that the choking Mach number is

  13. An Investigation into the Bias Error Caused by Anomalies in Static Pressure Taps

    NASA Astrophysics Data System (ADS)

    O'Connor, James Lloyd

    Static pressure taps are widely used in studying aerodynamics. They are used both in the design process (wind tunnel testing) and for controlling the aircraft (FADS). With the high levels of accuracy possible from current pressure measurement devices and the precise controls required for high-speed flights, bias caused by anomalies in pressure taps needed to be quantified. The parameters investigated in this study were the yaw angle, off-normal angle, and the diameter. The yaw angle was measured relative to the direction of air flow and varied between 0 and 360 degrees. The off-normal angles were measured relative to an axis perpendicular to the surface and were: 30, 20, and 10 degrees. The diameter of the pressure tap was varied up to 50% of the boundary layer thickness. For all of these a 0.026" diameter tap was used as a reference this corresponded to approximately 10% of the boundary layer thickness. It was discovered that a 30 degree off-normal tap with a yaw angle of 0 degrees gave a bias error of 0.3% of the dynamic pressure. Other off-normal and yaw angles gave smaller bias errors. Yaw angles of between 0 and 90 degrees gave positive bias errors and yaw angles between 90 and 180 degrees gave negative bias errors. These errors decreased as the off-normal angle decreased. It was also found that larger diameter taps gave larger pressure bias errors. Taps with a diameter smaller than the reference gave negative bias relative to the reference tap pressure. All results were non-dimensionalized by the boundary layer thickness, or the dynamic pressure.

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

    SciTech Connect

    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

    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.

  15. 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

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

    2007-01-01

    In Part 1 of this paper, the theoretical models, integrating the fan airflow, fan head, air leakage factors, are developed to analyze the impacts of the static pressure reset on both pressure dependent and pressure independent terminal boxes...

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

    SciTech Connect

    Evans, W J; Jenei, Z

    2009-09-17

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

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

    E-print Network

    Kimla, John

    2010-07-14

    particular system, or lack thereof, this tool will facilitate the selection of a SPR control strategy. A field experiment was conducted on a single duct variable air volume system with fixed discharge air temperature and static pressure setpoints. Finally...

  18. Seat interface pressures of individuals with paraplegia: Influence of dynamic wheelchair locomotion compared with static seated measurements

    Microsoft Academic Search

    Thomas W. Kernozek; Jeff E. Lewin

    1998-01-01

    Objective: To provide a comparison of the seat interface pressures between static seating and dynamic seating during wheelchair locomotion of individuals with paraplegia.Design: Repeated measures multivariate analysis of variance (MANOVA) comparing two conditions: static seat and dynamic seat interface pressures.Setting: University campus and clinic.Participants: Fifteen participants, each of whom propelled a manual wheelchair for at least 5 hours per week

  19. Subsonic wind-tunnel tests of a trailing-cone device for calibrating aircraft static pressure systems

    NASA Technical Reports Server (NTRS)

    Jordan, F. L., Jr.; Ritchie, V. S.

    1973-01-01

    A trailing-cone device for calibrating aircraft static-pressure systems was tested in a transonic wind tunnel to investigate the pressure-sensing characteristics of the device including effects of several configuration changes. The tests were conducted at Mach numbers from 0.30 to 0.95 with Reynolds numbers from (0.9 x one million to 4.1 x one million per foot). The results of these tests indicated that the pressures sensed by the device changed slightly but consistently as the distance between the device pressure orifices and cone was varied from 4 to 10 cone diameters. Differences between such device-indicated pressures and free-stream static pressure were small, however, and corresponded to Mach number differences of less than 0.001 for device configurations with pressure orifices located 5 or 6 cone diameters ahead of the cone. Differences between device-indicated and free-stream static pressures were not greatly influenced by a protection skid at the downstream end of the pressure tube of the device nor by a 2-to-1 change in test Reynolds number.

  20. Static and dynamic fatigue behavior of glass filament-wound pressure vessels at ambient and cryogenic temperatures.

    NASA Technical Reports Server (NTRS)

    Hanson, M. P.

    1972-01-01

    Investigation of the pressure load carrying capacity and fatigue strength of filament-wound glass-reinforced plastic pressure vessels subjected to static and cyclic loading at ambient and cryogenic (liquid nitrogen) temperature environments. The results indicate that the static fatigue problem is not critical at cryogenic temperatures. Under static loading at liquid nitrogen temperature, a reinforced plastic cylinder sustained pressurization for 88 days without failure at about 90% of the single cycle burst strength. At ambient temperature, the static life at 90% of the burst strength was about 7 min. Under cyclic loading in liquid nitrogen, no failure resulted after 1509 cycles at 55% of the single cycle burst strength. Under the same cyclic loading at ambient temperature, the test results would predict failure in the reinforced plastic. The results of similar tests upon adhesively bonded polyimide aluminum-foil lined cylinders are also reviewed.-

  1. Pressure &Pressure & TemperatureTemperature

    E-print Network

    California at Santa Cruz, University of

    to measure atmospheric pressure, and thermometer toprobe to measure atmospheric pressure, and thermometer toprobe to measure atmospheric pressure, and thermometer toprobe to measure atmospheric pressurePressure &Pressure & TemperatureTemperature vs.vs. AltitudeAltitude #12;Presented by:Presented by

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

    PubMed

    Matsuda, Shigeki; Demura, Shinichi; Uchiyama, Masanobu

    2008-05-01

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

  3. A Novel Procedure to Determine Optimal Air Static Pressure Set-points and Reset Schedules in VAV Air Handling Units

    E-print Network

    Zhu, Y.; Liu, M.; Claridge, D. E.; Turner, W. D.; Powell, T.

    1998-01-01

    Air static pressure set-point or schedule for VAV AHLJ systems is one of the most crucial operational parameters for satisfy lug the building load, maintaining the room comfort level and saving energy costs. This paper presents a novel procedure...

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

    NASA Astrophysics Data System (ADS)

    Liao, JianHui; Zhuang, Zhuo

    2012-04-01

    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.

  5. Impacts of Static Pressure Reset on VAV System Air Leakage, Fan Power and Thermal Energy - Part I: Theoretical Model and Simulation 

    E-print Network

    Liu, M.; Feng, J.; Wang, Z.; Wu, L.; Zheng, K.; Pang, W.

    2007-01-01

    to the terminal box and box inlet static pressure. Typically, the air duct static pressure is set as a constant set point based on the system design information and sensor location. However, under partial load conditions, the terminal box dampers have to be closed...

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

    NASA Technical Reports Server (NTRS)

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

    1982-01-01

    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.

  7. Under Pressure: Your Blood Pressure

    NSDL National Science Digital Library

    2012-06-26

    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.

  8. Fluctuating pressures on fan blades of a turbofan engine: Static and wind-tunnel investigations

    NASA Astrophysics Data System (ADS)

    Schoenster, J. A.

    1982-03-01

    To investigate the fan noise generated from turbofan engines, miniature pressure transducers were used to measure the fluctuating pressure on the fan blades of a JT15D engine. Tests were conducted with the engine operating on an outdoor test stand and in a wind tunnel. It was found that a potential flow interaction between the fan blades and six, large support struts in the bypass duct is a dominant noise source in the JT15D engine. Effects of varying fan speed and the forward speed on the blade pressure are also presented.

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

    NASA Astrophysics Data System (ADS)

    Horak, W.; Szcz?ch, M.

    2013-02-01

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

  10. Numerical investigation of static flow instability in a low-pressure subcooled boiling channel

    Microsoft Academic Search

    Y. Li; G. H. Yeoh; J. Y. Tu

    2004-01-01

    A three-dimensional two-fluid model to predict subcooled boiling flow at low pressure is presented. The model is adopted to investigate the two-phase flow and heat transfer characteristics in a heated channel. The presence of bubbles as a consequence of heating flow through a vertical rectangular channel has a significant effect on the overall pressure drop along the channel. Numerical results

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

    SciTech Connect

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

    2011-05-01

    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.

  12. Air Pressure

    NSDL National Science Digital Library

    University of Illinois

    2009-01-01

    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.

  13. Feeling Pressured

    NSDL National Science Digital Library

    2012-07-12

    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.

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

    E-print Network

    Al Jughaiman, Bader K.

    2009-06-02

    section holds the test bearing and all the associated instrumentation, namely, non-contacting eddy-current proximity sensors, accelerometers, pressure transducers and thermocouples. A pneumatic loader and two hydraulic shakers apply static and dynamic.... 4 Test rig main section Loading Configuration Two orthogonally mounted hydraulic shaker heads are attached to the stator middle section. The stator-shaker-stinger arrangement is shown in Fig. 5, as observed from the non-drive end...

  15. Study on Fuzzy Control of Supply Air Static Pressure for a Marine Variable-Air-Volume Air-Conditioning System

    Microsoft Academic Search

    Wu Chen; Yanjie Lei

    2010-01-01

    In this paper, the advanced marine variable-air-volume (VAV) air-conditioning (A\\/C) system was taken to be the control object. By using fuzzy control theory, a fuzzy controller was developed for the variable-frequency supply air fan in the marine VAV A\\/C system to control its supply air static pressure. An experimental test for the fuzzy controller developed was carried out. Step changes

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

    E-print Network

    Al Jughaiman, Bader K.

    2009-06-02

    section holds the test bearing and all the associated instrumentation, namely, non-contacting eddy-current proximity sensors, accelerometers, pressure transducers and thermocouples. A pneumatic loader and two hydraulic shakers apply static and dynamic.... 4 Test rig main section Loading Configuration Two orthogonally mounted hydraulic shaker heads are attached to the stator middle section. The stator-shaker-stinger arrangement is shown in Fig. 5, as observed from the non-drive end...

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

    SciTech Connect

    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

    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.

  18. Standard Test Method for Water Penetration of Flat Plate Solar Collectors by Uniform Static Air Pressure Difference

    E-print Network

    American Society for Testing and Materials. Philadelphia

    1986-01-01

    1.1 This test method covers the determination of the resistance of flat plate solar collectors to water penetration when water is applied to their outer surfaces with a static air pressure at the outer surface higher than the pressure at the interior of the collector. 1.2 This test method is applicable to any flat plate solar collector. 1.3 The proper use of this test method requires a knowledge of the principles of pressure and deflection measurement. 1.4 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only. 1.5 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. Specific precautionary information is contained in Section 6.

  19. Static internal pressure capacity of Hanford Single-Shell Waste Tanks

    SciTech Connect

    Julyk, L.J.

    1994-07-19

    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.

  20. Influence of alcohol intake on the parameters evaluating the body center of foot pressure in a static upright posture.

    PubMed

    Noda, Masahiro; Demura, Shinichi; Yamaji, Shunsuke; Kitabayashi, Tamotsu

    2004-06-01

    To examine the influence of alcohol intake on various parameters evaluating the change in body center of foot pressure during a static upright posture, 11 healthy young males and females gave measures of blood pressure, heart rate, whole body reaction time, standing on one leg with eyes closed, and body stability for 60 sec. in the Romberg posture (open eyes, closed feet) before and after the alcohol intake. The measurement was made with an Anima's stabilometer G5500. Data sampling frequency was 20 Hz. The subjects drank alcohol (Japanese sake 540 ml) within 10 min. After 10, 20, and 30 min. of alcohol intake, the same measurements were carried out. 24 parameters with higher trial-to-trial reliability were selected from the following 7 domains: distance, mean center of foot pressure, distribution of amplitude, area, velocity, frequency (power spectrum), and direction (vector) of body-sway and velocity. Parameters for distance, velocity, and area of body-sway significantly changed after alcohol intake, but the mean center of foot pressure and frequency of body-sway were unchanged. It was inferred that the mean center of foot pressure and frequency for body-sway did not change even if a nervous function decreased by the alcohol intake, and an upright posture was maintained by increasing the distance, area, and velocity of body-sway. Further, body-sway tends to increase in the medial/lateral direction as compared with the anterior/posterior direction. PMID:15209303

  1. Ultrahigh pressures

    NASA Astrophysics Data System (ADS)

    Jayaraman, A.

    1986-06-01

    This article reviews mainly the use of the diamond anvil cell (DAC) for ultrahigh-pressure generation (a few hundred GPa) and the various techniques employed in studying the high-pressure behavior of solids. A brief historical introduction to devices used in the prediamond-anvil era is presented in Sec. I. The basic principles of the modern DAC, ultrahigh-pressure generation, and pressure calibration are presented. Among the techniques used, x-ray diffraction, optical spectroscopy including Raman and Brillouin spectroscopy, microscopy, electrical resistance,and Mössbauer measurements, and positron annihilation studies with the DAC are reviewed. High-temperature-high-pressure (HT-HP) and low-temperature-high-pressure (LT-HP) generation in the DAC, and the problems associated with pressure calibration under these conditions are discussed. A brief section is devoted to the sintered diamond-tipped anvil apparatus, for it offers a very convenient way of studying resistance changes and superconductivity to 50-GPa pressure at normal and at liquid-He temperatures. In Sec. IV, Raman studies on solid H2 and solid N2 to about 150 GPa, p-v studies on Xe, CsI to 50 GPa, the metallization of CsI, and superconductivity of Si high-pressure polymorphs are presented. Present trends and future possibilities for ultrahigh-pressure research are briefly set out in Sec. V.

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

    E-print Network

    Williams, Garrett Edwin

    1979-01-01

    to the conclusion that the platform failed primarily as a result of wave- induced soil movements which caused the piling to fail in bending. In reference to the platform failure during Hurricane Camille, Dea (1) stated that excess pore water pressures...

  3. Selection and static calibration of the Marsh J1678 pressure gauge

    NASA Astrophysics Data System (ADS)

    Oxendine, Charles R.; Smith, Howard W.

    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.

  4. EXPLORING STRUCTURAL BOND ENERGY RELEASE (SBER) IN NANODIAMONDS USING QUANTUM MOLECULAR DYNAMICS AND STATIC HIGH PRESSURE

    Microsoft Academic Search

    William D. Mattson; Radhakrishnan Balu; Betsy M. Rice; Jennifer A. Ciezak

    We present a combined experimental and theoretical study on carbon nanodiamonds using Raman and DAC experimentation and ab initio calculations. Our calculations confirm the surface reconstruction to a fullerene-like structure, and indicate compression of the diamond core, producing an estimated internal pressure of 50 GPa. Quantum molecular dynamics simulations of hypervelocity collisions of NDs show that upon collision shock-induced amorphization

  5. Selection and static calibration of the Marsh J1678 pressure gauge

    NASA Technical Reports Server (NTRS)

    Oxendine, Charles R.; Smith, Howard W.

    1993-01-01

    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.

  6. Static Pressure Loss in 12”, 14”, and 16” Non-metallic Flexible Duct 

    E-print Network

    Cantrill, David Lee

    2013-08-01

    This study was conducted to determine the effects of compression on pressure drops in non-metallic flexible duct. Duct sizes of 12”, 14” and 16” diameters were tested at a five different compression ratios (maximum stretch, 4%, 15%, 30% and 45...

  7. Under Pressure

    NSDL National Science Digital Library

    American Museum of Natural History

    2002-01-01

    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.

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

    PubMed

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

    2012-02-01

    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

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

    Microsoft Academic Search

    R. Boehler

    1993-01-01

    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

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

    NASA Technical Reports Server (NTRS)

    Igoe, William B.

    1991-01-01

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

  11. Development of flightweight static face seals for 75.84 MPa /11 000 psi/ pressure and cryogenic temperatures

    NASA Technical Reports Server (NTRS)

    Daniels, C. M.

    1978-01-01

    The development of a static seal configuration to meet the lightweight low-leakage requirements of the Space Shuttle Main Engine (pressure carrying capability of up to 75.84 MPa) is discussed. The design features, fabrication methods, lab testing, and performance of seal are examined. Flange and bolt details of the joint assembly are considered with attention to an ultrasonic technique for measuring preload in the bolts. Methods used for leak testing in the laboratory and in the field are described; the practicality of the procedures is considered. Attention is directed to hydrogen-environment embrittlement and its influence on seal and joint design.

  12. Static and unsteady pressure measurements on a 50 degree clipped delta wing at M = 0.9. [conducted in the Langley Transonic Dynamics Tunnel

    NASA Technical Reports Server (NTRS)

    Hess, R. W.; Wynne, E. C.; Cazier, F. W.

    1982-01-01

    Pressures were measured with Freon as the test medium. Data taken at M = 0.9 is presented for static and oscillatory deflections of the trailing edge control surface and for the wing in pitch. Comparisons of the static measured data are made with results computed using the Bailey-Ballhaus small disturbance code.

  13. Measuring Pressure

    NSDL National Science Digital Library

    AMPS GK-12 Program,

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

  14. Under Pressure

    NSDL National Science Digital Library

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

  15. Under Pressure

    NSDL National Science Digital Library

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

  16. Differential Pressures on a Pitot-venturi and a Pitot-static Nozzle over 360 Degrees Pitch and Yaw

    NASA Technical Reports Server (NTRS)

    Bear, R M

    1928-01-01

    Measurements of the differential pressures on two navy air-speed nozzles, consisting of a Zahm type Pitot-Venturi tube and a SQ-16 two-pronged Pitot-static tube, in a tunnel air stream of fixed speed at various angles of pitch and yaw between 0 degrees and plus or minus 180 degrees. This shows for a range over -20 degrees to +20 degrees pitch and yaw, indicated air speeds varying very slightly over 2 per cent for the Zahm type and a maximum of about 5 per cent for the SQ-16 type from the calibrated speed at 0 degree. For both types of air-speed nozzle the indicated air speed increases slightly as the tubes are pitched or yawed several degrees from their normal 0 degrees altitude, attains a maximum around plus or minus 15 degrees to 25 degrees, declines rapidly therefrom as plus or minus 40 degrees is passed, to zero in the vicinity of plus or minus 70 degrees to 100 degrees, and thence fluctuates irregular from thereabouts to plus or minus 180 degrees. The complete variation in indicated air speed for the two tubes over 360 degree pitch and yaw is graphically portrayed in figures 9 and 10. For the same air speed and 0 degree pitch and yaw the differential pressure of the Zahm type Pitot-Venturi nozzle is about seven times that of the SQ-16 type two-prolonged Pitot-static nozzle.

  17. 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.

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

    NASA Technical Reports Server (NTRS)

    Silsby, Norman S.

    1959-01-01

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

  19. Flutter Sensitivity to Boundary Layer Thickness, Structural Damping, and Static Pressure Differential for a Shuttle Tile Overlay Repair Concept

    NASA Technical Reports Server (NTRS)

    Scott, Robert C.; Bartels, Robert E.

    2009-01-01

    This paper examines the aeroelastic stability of an on-orbit installable Space Shuttle patch panel. CFD flutter solutions were obtained for thick and thin boundary layers at a free stream Mach number of 2.0 and several Mach numbers near sonic speed. The effect of structural damping on these flutter solutions was also examined, and the effect of structural nonlinearities associated with in-plane forces in the panel was considered on the worst case linear flutter solution. The results of the study indicated that adequate flutter margins exist for the panel at the Mach numbers examined. The addition of structural damping improved flutter margins as did the inclusion of nonlinear effects associated with a static pressure difference across the panel.

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

    NASA Astrophysics Data System (ADS)

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

    2014-11-01

    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.

  1. The effects of barometric relief dampers on internal static pressure, air quality, and energy consumption for a typical large-scale retail building

    Microsoft Academic Search

    Wei Guo; Darin Nutter

    2012-01-01

    In order to prevent building over-pressurization, many roof-top units on large-scale retail buildings are equipped with barometric relief dampers. In this study, the effects of barometric relief dampers on internal static pressure, indoor air quality, and heating and cooling energy consumption for a typical large-scale retail building were investigated. The air flow characteristics of barometric relief dampers (i.e., the relationship

  2. Pressure Interactions

    NSDL National Science Digital Library

    Wolfgang Christian

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

  3. High Blood Pressure

    MedlinePLUS

    ... of this page please turn Javascript on. High Blood Pressure What Is High Blood Pressure? Click for more information Blood pressure is ... active. So it varies throughout the day. High Blood Pressure (Hypertension) A systolic blood pressure of 140 ...

  4. Blood pressure measurement

    MedlinePLUS

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

  5. Pressure transducer

    DOEpatents

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

    1989-01-01

    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.

  6. Pressurized hopper

    SciTech Connect

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

    1980-04-01

    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)

  7. Pressure transducer

    DOEpatents

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

    1987-02-13

    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.

  8. Space shuttle: Static surface pressures of the 0.004 scale 049 orbiter in the launch configuration

    NASA Technical Reports Server (NTRS)

    Buchholz, R. E.; Gamble, M.

    1972-01-01

    Wing and lower body surface static pressure data for the space shuttle 049 orbiter while in the launch configuration were obtained. The purpose of the test was to determine the optimum incidence position of the orbiter relative to the hydrogen-oxygen (HO) tank and the optimum radial position of the solid rocket motors (SRM) on the HO tank. The orbiter was mounted on the HO tank at incidence angles of 0 and -1.5 degrees to determine the optimum incidence position. The SRM boosters were tested at radial positions of 75, 90, and 135 degrees on the HO tank to determine their optimum position with respect to the loads imposed on the orbiter. The test was conducted in the tunnel over a Mach number range of 0.6 to 4.96. Angle of attack was varied from -8 to +8 degrees at zero degree angle of sideslip, and at sideslip angles varying from -6 to +6 degrees at zero degree angle of attack.

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

    NASA Technical Reports Server (NTRS)

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

    1985-01-01

    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.

  10. Understanding Blood Pressure Readings

    MedlinePLUS

    Understanding Blood Pressure Readings Updated:Apr 28,2015 Blood pressure is typically recorded as two numbers, written as a ... blood). What is the AHA recommendation for healthy blood pressure? This chart reflects blood pressure categories defined ...

  11. Differential pressure pin discharge apparatus

    SciTech Connect

    Oakley, D.J.

    1984-05-30

    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.

  12. Pressurized fiber optic cable designs

    Microsoft Academic Search

    M. Miltner; A. Gittle; C. Rim

    1986-01-01

    Different concepts of pressurized fiber optic cable systems are presented. These systems maintain a static pressure throughout the continuous system length into the termination building including all splice points comprising the route. In these redundantly protective systems, an increase in the rate of gas flow into the system indicates outer sheath damage or penetration. The evolution of existing designs are

  13. Power spectrum characteristics of body sway time series and velocity time series of the center of foot pressure during a static upright posture in preschool children

    Microsoft Academic Search

    S. Demura; T. Kitabayashi

    2008-01-01

    This study aimed to assess individual and gender differences in power spectra in the body sway time series and sway velocity\\u000a time series during a static upright standing posture using 30 preschool children and their spectrum distribution characteristics.\\u000a The center of pressure (COP) movement for 1 min was measured twice with a 1 min rest on an Anima stabilometer. The

  14. Urethral pressure variations in healthy male volunteers

    Microsoft Academic Search

    H. J. Kirkeby; S. Sørensen; E. U. Poulsen

    1989-01-01

    Urethral pressures are usually considered to be static and only few authors have emphasized timerelated pressure changes. We conducted a study on 10 healthy male volunteers, monitoring the urethral pressures at maximal urethral closure pressure, 2.5 cm proximal (bladder neck) and 2.5 cm distal (pars bulbosa) respectively over 30 min periods. At the bladder neck only sporadic waves were seen.

  15. Downhole pressure attenuation apparatus

    SciTech Connect

    Ricles, T.D.; Barton, J.A.

    1992-02-18

    This patent describes a process for preventing damage to tool strings and other downhole equipment in a well caused by pressures produced during detonation of one or more downhole explosive devices. It comprises adding to a tool string at least one pressure attenuating apparatus for attenuating the peak pressure wave and quasi-static pressure pulse produced by the explosive devices, the pressure attenuating apparatus including an initially closed relief vent including tubing means supporting a plurality of charge port assemblies each including an explosive filled shaped charge and a prestressed disc, the shaped charges interconnected by a detonating cord, the amount of explosive in each shaped charge being sufficient to rupture its associated disc without damaging surrounding tubular bodies in the well, and a vent chamber defined by the tubing means and providing a liquid free volume, and opening the relief vent substantially contemporaneously with downhole explosive device detonation by detonating the shaped charges to rupture the discs of the charge port assemblies.

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

    Microsoft Academic Search

    T. A. Butler; J. G. Bennett

    1981-01-01

    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

  17. 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,...

  18. Low blood pressure

    MedlinePLUS

    Low blood pressure; Blood pressure - low; Postprandial hypotension; Orthostatic hypotension; Neurally mediated hypotension; NMH ... Blood pressure varies from one person to another. A drop as little as 20 mmHg, can cause ...

  19. High Blood Pressure (Hypertension)

    MedlinePLUS

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

  20. High Blood Pressure

    MedlinePLUS

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

  1. Aircraft Performance: Atmospheric Pressure

    E-print Network

    Aircraft Performance: Atmospheric Pressure FAA Handbook of Aeronautical Knowledge Chap 10 #12 ­ 21% Oxygen ­ 1% other gases (argon, helium, etc) · Most oxygen Atmospheric Pressure;High Density Altitude (worse performance) · High elevations · Low atmospheric pressures · High

  2. Intracranial pressure monitoring

    MedlinePLUS

    ... head. The monitor senses the pressure inside the skull and sends measurements to a recording device. ... are three ways to monitor pressure in the skull (intracranial pressure). INTRAVENTRICULAR CATHETER The intraventricular catheter is ...

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

    SciTech Connect

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

    1981-01-01

    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.

  4. Consequences of static and pulsatile pressure on transmembrane exchanges during in vitro microdialysis: implication for studies in cardiac physiology

    Microsoft Academic Search

    E. M. Siaghy; B. Oesterlé; A. Kheiri; P. Halejcio-Delophont; D. Ungureanu-Longrois; J. P. Villemot; P. M. Mertes

    1999-01-01

    Microdialysis is an established technique for measuring the kinetics of various neurotransmitters within the extracellular\\u000a space in the field of neurochemistry. Recently, its use has been extended to sampling in other tissues, including liver, kidney\\u000a and the heart. A persistent problem in cardiac microdialysis concerns two parameters related to myocardial function: pressure\\u000a and frequency (heart rate). The aim of the

  5. Role of intra-abdominal pressure in the unloading and stabilization of the human spine during static lifting tasks

    Microsoft Academic Search

    N. Arjmand; A. Shirazi-Adl

    2006-01-01

    The role of intra-abdominal pressure (IAP) in unloading the spine has remained controversial. In the current study, a novel kinematics-based approach along with a nonlinear finite-element model were iteratively used to calculate muscle forces, spinal loads, and stability margin under prescribed postures and loads measured in in vivo studies. Four coactivity levels (none, low, moderate, and high) of abdominal muscles

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

    SciTech Connect

    Clauss, D.B. (ed.)

    1987-05-01

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

  7. Vapor pressure of germanium precursors

    Microsoft Academic Search

    J. Pangrác; M. Fulem; E. Hulicius; K. Melichar; T. Šime?ek; K. Ruzicka; P. Morávek; V. R?ži?ka; S. A. Rushworth

    2008-01-01

    The vapor pressure of two germanium precursors tetrakis(methoxy)germanium (Ge(OCH3)4, CASRN 992-91-6) and tetrakis(ethoxy)germanium (Ge(OC2H5)4, CASRN 14165-55-0) was determined using a static method in the temperature range 259–303K. The experimental vapor pressure data were fit with the Antoine equation. The mass spectra before and after degassing by vacuum distillation at low temperature are also reported and discussed.

  8. Pressure Mapping Comparison of Four OR Surfaces.

    PubMed

    Kirkland-Walsh, Holly; Teleten, Oleg; Wilson, Machelle; Raingruber, Bonnie

    2015-07-01

    Mortality and health care costs associated with hospital-acquired pressure ulcers (HAPUs) increase yearly. After four hours of surgery, the risk of developing a pressure ulcer increases by 33% for every 30 minutes of surgery. Prolonged immobility, lower blood pressures, and increased surface interface pressure may hinder the blood supply delivered to the skin, eventually leading to pressure ulcers. We measured and compared four different OR surfaces to identify the most effective pressure redistribution surface for prolonged OR procedures. The best surface attributes that provide efficient pressure redistribution should have the following properties: the lowest average interface pressure, the lowest peak interface pressure, and the highest skin contact area. Although all surfaces had similar average interface pressures, the air-inflated static seat cushion had the best pressure redistribution properties in the sacral region compared with the other surfaces tested. PMID:26119617

  9. Measuring Time-Averaged Blood Pressure

    NASA Technical Reports Server (NTRS)

    Rothman, Neil S.

    1988-01-01

    Device measures time-averaged component of absolute blood pressure in artery. Includes compliant cuff around artery and external monitoring unit. Ceramic construction in monitoring unit suppresses ebb and flow of pressure-transmitting fluid in sensor chamber. Transducer measures only static component of blood pressure.

  10. What Causes Pressure?

    NSDL National Science Digital Library

    Colorado State University

    2009-01-01

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

  11. 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)

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

    1977-01-01

    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.

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

    SciTech Connect

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

    1986-07-01

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

  13. Pressure Dome for High-Pressure Electrolyzer

    NASA Technical Reports Server (NTRS)

    Norman, Timothy; Schmitt, Edwin

    2012-01-01

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

  14. Flutter spectral measurements using stationary pressure transducers

    NASA Technical Reports Server (NTRS)

    Kurkov, A. P.

    1980-01-01

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

  15. In Situ Measurement of Magnesium Carbonate Formation from CO2 Using Static High-Pressure and -Temperature 13

    E-print Network

    Skemer, Philip

    . This carbonation reaction illustrates the importance of static (unmixed) reaction systems at sequestration in the chemical and physical implications of carbon sequestration, a process by which CO2 generated as a byproductIn Situ Measurement of Magnesium Carbonate Formation from CO2 Using Static High

  16. Pressure Sensitive Paints

    NASA Technical Reports Server (NTRS)

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

    1999-01-01

    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.

  17. Atmospheric Pressure Indicator.

    ERIC Educational Resources Information Center

    Salzsieder, John C.

    1995-01-01

    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)

  18. Fluid Pressure Calculator

    NSDL National Science Digital Library

    Jimmy Raymond

    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.

  19. 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

  20. Blood Pressure Medicines

    MedlinePLUS

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

  1. Portable Potable Pressure

    NSDL National Science Digital Library

    Eric Muller

    2004-01-01

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

  2. What is Blood Pressure?

    NSDL National Science Digital Library

    Barbara Z. Tharp

    2009-01-01

    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.

  3. Diffusion Pump Pressure Gauge

    Microsoft Academic Search

    J A V Fairbrother; J. A. V

    1948-01-01

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

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

    E-print Network

    Kimla, John

    2010-07-14

    , an air-side model of the experimental system was created using detailed building design information and calibrated using field measurements. This model was used to estimate the fan energy required to supply the trended airflow data using fixed static...

  5. Optional Barometric Pressure Protocol

    NSDL National Science Digital Library

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

    2003-08-01

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

  6. Pressure dependence of viscosity

    Microsoft Academic Search

    Jürn W. P. Schmelzer; Edgar D. Zanotto; Vladimir M. Fokin

    2005-01-01

    We reanalyze the pressure dependence of viscosity of liquids of constant composition under isothermal conditions. Based exclusively on very general considerations concerning the relationship between viscosity and ``free volume,'' we show that, at moderate values of pressure, viscosity increases, as a rule, with increasing pressure, provided the liquid is in stable or metastable (undercooled) equilibrium states. However, even if the

  7. Pressure dependence of viscosity

    Microsoft Academic Search

    Edgar D. Zanotto; Vladimir M. Fokin

    2005-01-01

    We reanalyze the pressure dependence of viscosity of liquids of constant composition under isothermal conditions. Based exclusively on very general considerations concerning the relationship between viscosity and “free volume,” we show that, at moderate values of pressure, viscosity increases, as a rule, with increasing pressure, provided the liquid is in stable or metastable (undercooled) equilibrium states. However, even if the

  8. Inertia diaphragm pressure transducer

    NASA Technical Reports Server (NTRS)

    Seegmiller, H. L. B.

    1971-01-01

    Transducer measures gas pressure profiles in high temperature, short duration, gas flows usually found in devices where pressure pulses may have durations of few microseconds to several milliseconds. Assembly includes fluid delay line, delay chamber, and flow restrictor for equalizing steady state pressure on diaphragm's sides

  9. Pressure ulcer prevention.

    PubMed

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

    2004-01-01

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

  10. High pressure ices

    PubMed Central

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

    2012-01-01

    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

  11. Pressure reducing regulator

    DOEpatents

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

    1995-01-01

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

  12. Pressure reducing regulator

    DOEpatents

    Whitehead, J.C.; Dilgard, L.W.

    1995-10-10

    A pressure reducing regulator that controls its downstream or outlet pressure to a fixed fraction of its upstream or inlet pressure is disclosed. The regulator includes a housing which may be of a titanium alloy, within which is located a seal or gasket at the outlet end which may be made of annealed copper, a rod, and piston, each of which may be made of high density graphite. The regulator is insensitive to temperature by virtue of being without a spring or gas sealed behind a diaphragm, and provides a reference for a system in which it is being used. The rod and piston of the regulator are constructed, for example, to have a 1/20 ratio such that when the downstream pressure is less than 1/20 of the upstream pressure the regulator opens and when the downstream pressure exceeds 1/20 of the upstream pressure the regulator closes. 10 figs.

  13. Gender differences in body-sway factors of center of foot pressure in a static upright posture and under the influence of alcohol intake.

    PubMed

    Kitabayashi, Tamotsu; Demura, Shinichi; Noda, Masahiro; Yamada, Takayoshi

    2004-07-01

    This study aimed to examine gender differences in 4 body-sway factors of the center of foot pressure (CFP) during a static upright posture and the influence of alcohol intake on them. Four body-sway factors were interpreted in previous studies using factor analysis (the principal factor method and oblique solution by promax-rotation) on 220 healthy young males and females as follows; unit time sway, front-back sway, left-right sway and high frequency band power. The CFP measurement for 1 min was carried out twice with 1 min rest. The measurements of blood pressure, heart rate, whole body reaction time, standing on one leg with eyes closed, and CFP were carried out before and after the alcohol intake using 11 healthy young males and females. The measurement device used was an Anima's stabilometer G5500. The data sampling frequency was 20 Hz. Reliability of 4 body-sway factors was very high. Significant gender differences were found in the left-right sway and the high frequency band power factors, but the influence on body-sway is, as a whole, can be disregarded. These four sway factors can determine the influence of alcohol intake as efficient as 32 sway parameters. PMID:15314268

  14. Pressure regulating valve controller

    SciTech Connect

    Goodman, R.B.

    1988-04-05

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

  15. Direct measurement of cutaneous pressures generated by pressure garments

    Microsoft Academic Search

    H. P. Giele; K. Liddiard; K. Currie; F. M. Wood

    1997-01-01

    Pressure garments are the mainstay of burn scar management despite limited scientific evidence. This study demonstrates a simple method of directly measuring the cutaneous pressures generated by a pressure garment. The results show pressure garments generate an increase in subdermal pressures in the range 9–90 mmHg depending on the anatomical site. Garments over soft sites generate pressures ranging from 9

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

    NASA Astrophysics Data System (ADS)

    Alves de Mesquita, Jayme; Lopes de Melo, Pedro

    2004-03-01

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

  17. High Blood Pressure in Pregnancy

    MedlinePLUS

    ... Are the Effects of High Blood Pressure in Pregnancy? Although many pregnant women with high blood pressure ... Common Are High Blood Pressure and Preeclampsia in Pregnancy? High blood pressure problems occur in 6 percent ...

  18. Differential pressure sensor

    SciTech Connect

    Knecht, T.A.; Prairie, E.; Frick, R.L.; Bruesehoff, S.M

    1989-05-30

    This patent describes a sensor for sensing differential pressure in a fluid and for providing an output indicative of such pressure. The sensor consists of: a pair of inlet means, each having a hole extending from an inlet region thereon to a substantially planar support surface thereon for conveying a fluid pressure from each inlet region to each support surface; diaphragm means for sensing the pressure, the diaphragm means having an outer rim sealingly bonded to both support surfaces to surround the holes, and having a deflectable region bounded by the rim for deflection by the pressure, the deflectable region having a pair of outwardly facing surfaces each having a portion with a concave shape when the deflectable region is at rest; and sensing means disposed in the sensor for sensing the deflection of the deflectable region and for providing an output indicative of the pressure.

  19. Blade pressure measurements

    NASA Astrophysics Data System (ADS)

    Chivers, J. W. H.

    Three measurement techniques which enable rotating pressures to be measured during the normal operation of a gas turbine or a component test rig are described. The first technique was developed specifically to provide steady and transient blade surface pressure data to aid both fan flutter research and general fan performance development. This technique involves the insertion of miniature high frequency response pressure transducers into the fan blades of a large civil gas turbine. The other two techniques were developed to measure steady rotating pressures inside and on the surface of engine or rig turbine blades and also rotating pressures in cooling feed systems. These two low frequency response systems are known as the "pressure pineapple' (a name which resulted from the shape of the original prototype) and the rotating scanivalve.

  20. Pressurized burner test facility

    Microsoft Academic Search

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

    1993-01-01

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

  1. High temperature pressure gauge

    DOEpatents

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

    1981-01-01

    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.

  2. Ruby under pressure

    Microsoft Academic Search

    K. Syassen

    2008-01-01

    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),

  3. [Arterial pulse pressure].

    PubMed

    Mourad, Jean-Jacques

    2002-09-21

    A WELL IDENTIFIED RISK FACTOR: Other than systolic, diastolic and mean pressure, arterial pulse pressure (or differential pressure) is an independent factor of cardiovascular and notably coronary risk. The role of this factor is now clearly quantified in untreated hypertensive patients, but also in treated apparently controlled patients, and in patients with normal blood pressure. Demonstration of the deleterious role of an increase in pulse pressure was also made in populations at high risk of events such as heart failure, post-infarction or in hemodialyzed patients. FROM A THERAPEUTIC POINT OF VIEW: Antihypertensive treatments have inconstant efficacy on pulse pressure and new therapeutic routes appear promising. However, in the absence of available proof that a strategy axed on the decrease in pulse pressure improves cardiovascular prognosis, current recommendations do not yet include pulse pressure levels in therapeutic strategies. AN EFFICIENT MARKER: Whilst awaiting further data, the measurement of pulse pressure, because of its pertinence and simplicity, provides the practitioner with one of the most efficient markers for screening persons at high risk of cardiovascular and particularly coronary risk. PMID:12378979

  4. Putting on the Pressure

    NSDL National Science Digital Library

    2012-08-03

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

  5. Sapphire tube pressure vessel

    DOEpatents

    Outwater, John O. (Cambridge, MA)

    2000-01-01

    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.

  6. Blood Pressure Control

    NASA Technical Reports Server (NTRS)

    1986-01-01

    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.

  7. Pressure-sensitive optrode

    DOEpatents

    Hirschfeld, T.B.

    1985-04-09

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

  8. Dual shell pressure balanced vessel

    DOEpatents

    Fassbender, Alexander G. (West Richland, WA)

    1992-01-01

    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.

  9. Manufacturing Diamond Under Very High Pressure

    NASA Technical Reports Server (NTRS)

    Voronov, Oleg

    2007-01-01

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

  10. Modeling Scala Media as a Pressure Vessel

    NASA Astrophysics Data System (ADS)

    Lepage, Eric; Olofsson, A.?Ke

    2011-11-01

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

  11. The Pressure of Radiation

    Microsoft Academic Search

    Oliver Heaviside

    1905-01-01

    THE success of Lebedeff and Nichols and Hull in recognising and measuring the pressure of radiation has aroused much interest in radiation pressure generally, real or apparent. It has some interesting and sometimes somewhat difficult theoretical aspects. In the first place, if the ether is really absolutely at rest (this rigidity is a very difficult idea), the moving force on

  12. Too Much Pressure!

    NSDL National Science Digital Library

    Integrated Teaching and Learning Program,

    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.

  13. Vapor Pressure Data

    NSDL National Science Digital Library

    Ohe, Shuzo.

    Created by Professor Shuzo Ohe of the Graduate School of Chemical Engineering and the Science University or Tokyo, this site offers vapor pressure data. Available in graph form, data represent vapor pressure (mmHg) as a function of temperature (C, or F). Substances are listed alphabetically and include acetaldehyde, acetic acid, benzene, butane, carbon dioxide, and water, to name a few.

  14. Fiber optic pressure sensor

    Microsoft Academic Search

    Joseph P. Ingold; Mei H. Sun; Russell N. Bigelow

    1991-01-01

    This paper highlights the efforts of the Naval Surface Warfare Center to develop a fiber optic pressure transducer. The initial application for this fiber optic sensor is to monitor the pressure in the sonar dome of a surface ship. This required a 0 - 100 pounds per square inch (gage) sensor. This sensor, developed by Luxtron, Incorporated, under a Small

  15. Pressure regulating valve controller

    Microsoft Academic Search

    1988-01-01

    In an aircraft cabin air conditioning system comprising a pair of air cycle refrigeration systems which provide chilled air to the cabin, airflow through the air cycle refrigeration systems being controllable by a pair of pressure regulating valves, each of the pressure regulating valves being disposed in a corresponding main airflow conduit and operated by a corresponding pneumatic valve actuator,

  16. PRESSURE ACTIVATED SEALANT TECHNOLOGY

    SciTech Connect

    Michael A. Romano

    2004-04-01

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

  17. Summing pressure compensation control

    SciTech Connect

    Myers, H.A.

    1988-04-26

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

  18. Cavitation pressure in liquid helium

    E-print Network

    Frederic Caupin; Sebastien Balibar

    2001-09-19

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

  19. An alternating pressure sequence proposal for an air-cell cushion for preventing pressure ulcers.

    PubMed

    Arias, Sandra; Cardiel, Eladio; Rogeli, Pablo; Mori, Taketoshi; Nakagami, Gojiro; Noguchi, Hiroshi; Sanada, Hiromi

    2014-01-01

    The distribution and release of pressure on ischial regions are two important parameters for evaluating the effectiveness of a cushion; especially the release of pressure over time on ischial tuberosities, which is significant for preventing pressure ulcers. The aim of this work is to evaluate the effect on interface pressure through the application of a proposed alternating pressure sequence for an air-cell cushion. Six healthy volunteers were asked to sit on the air cell cushion, in static and alternating modes, as well as on a typical foam cushion for 12 minutes. Interface pressure was monitored with a matrix sensor system. Interface pressure values on ischial tuberosities, user contact area and pressure distribution were analyzed. Results showed that IP on IT tends to increase in both foam and static cushions, while in alternating cushion IP on IT tends to decrease. User contact area was significantly larger in alternating cushion than in static or foam cushions. Moreover, there is a better pressure re-distribution with alternating cushion than with the other cushions. The goal of the alternating sequence is to redistribute pressure and stimulate the ischial regions in order to promote blood flow and prevent pressure occurring in wheelchair users. PMID:25570740

  20. Please cite this article in press as: Birkholzer, J.T., et al., Brine flow up a well caused by pressure perturbation from geologic carbon sequestration: Static and dynamic evaluations. Int. J. Greenhouse Gas Control (2011), doi:10.1016/j.ijggc.2011.01.003

    E-print Network

    Zhou, Quanlin

    2011-01-01

    by pressure perturbation from geologic carbon sequestration: Static and dynamic evaluations. Int. J.elsevier.com/locate/ijggc Brine flow up a well caused by pressure perturbation from geologic carbon sequestration: Static carbon sequestration (GCS) has drawn increasing con- sideration as a promising method to mitigate

  1. Pressure solution creep under cyclic loading

    Microsoft Academic Search

    Vladimir Traskine; Zoya Skvortsova; Alexey Muralev; Dmitry Zubov

    2009-01-01

    Pressure solution creep was studied on sodium chloride, calcium carbonate and ammonium nitrate in respective saturated aqueous\\u000a solutions under static loading and cyclic unloading. Ball indentation and powder compaction curves show that each transition\\u000a from static to cyclic regime produces an increase—sometimes manifold—in creep rate which lasts over the whole time of cyclic\\u000a impact. After returning to static regime, the

  2. Pressure energy storage device

    SciTech Connect

    Allison, J. H.

    1985-06-25

    A pressure energy storage device for the storage of kinetic energy of rotation in the form of potential energy of a compressed fluid and for converting the potential energy of the compressed fluid into kinetic energy of rotation. The pressure energy storage device includes a storage reservoir, a compressor driven by a rotating source to deliver pressurized fluid to the storage reservoir, and a primary fluid motor selectively operable to generate rotary motion by drawing off a portion of the pressurized fluid. The pressure energy storage device may be provided with an electric motor to drive the compressor, a generator driven by the primary fluid motor, a secondary fluid motor to drive the compressor by the exhaust fluid from the primary fluid motor, and an auxiliary pressurized fluid outlet, permitting the compressor to be driven by a rotating power source or an electrical power source and permitting the potential energy of the pressurized fluid to be used directly or to be converted to rotary motion or electrical current, as needed.

  3. Pressurizer tank upper support

    DOEpatents

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

    1994-01-11

    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.

  4. Pressurizer tank upper support

    DOEpatents

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

    1994-01-01

    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.

  5. Atmospheric Pressure During Landing

    NASA Technical Reports Server (NTRS)

    1997-01-01

    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.

  6. Tyre Pressure Monitoring Microsystems

    Microsoft Academic Search

    R. Grelland

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

  7. Flutter spectral measurements using stationary pressure transducers

    NASA Technical Reports Server (NTRS)

    Kurkov, A. P.

    1980-01-01

    The paper deals with an analysis procedure, based on engine-order sampling, which eliminates effectively the engine harmonics from the overall flutter spectra obtained with a case-mounted static pressure transducer. Qualitative spectral analyses of pressure data, performed on the basis of blade order sampling, are examined. The interference of blade motion with the pressure signal in the steep gradient portion of the blade passage is demonstrated, using optimal displacement spectra. Two methods which remove the contribution of blade motion from the blade-pressure-difference spectra are described.

  8. Calibrating pressure switch

    NASA Technical Reports Server (NTRS)

    Smith, N. J. (inventor)

    1968-01-01

    A pressure switch assembly comprising a body portion and a switch mechanism having a contact element operable between opposite limit positions is described. A diaphragm chamber is provided in the body portion which mounts therein a system diaphragm and a calibration diaphragm which are of generally the same configuration and having outer faces conforming to the inner and outer walls of the diaphragm chamber. The space between the inner faces of the diaphragms defines a first chamber section and the space between the outer face of one of the diaphragms and the outer wall of the diaphragm chamber defines a second chamber section. The body portion includes a system pressure port communicating with one of the chamber sections and a calibration pressure port communicating with the other chamber section. An actuator connected to one of the diaphragms and the contact element of the switch operates upon pressure change in the diaphragm sections to move said contact element between limit positions.

  9. The Pressure's On

    NSDL National Science Digital Library

    Frank L. Misiti Jr.

    2000-09-01

    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

  10. Capacitance pressure sensor

    SciTech Connect

    Eaton, W.P.; Staple, B.D.; Smith, J.H.

    2000-01-11

    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).

  11. Blood Pressure Checker

    NASA Technical Reports Server (NTRS)

    1979-01-01

    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.

  12. Low Differential Pressure Generator

    NASA Technical Reports Server (NTRS)

    Stout, Stephen J. (Inventor); Deyoe, Richard T. (Inventor)

    1997-01-01

    A method and apparatus for evaluating low differential pressure transducers includes a pressure generator in the form of a piston-cylinder assembly having a piston that may be manually positioned precisely within the cylinder to change the volume and thus the pressure at respective sides of the piston. At one side of the piston the cylinder communicates with a first chamber and at the other side of the piston the cylinder communicates with a second chamber, the first and second chambers being formed within a common tank by a partition wall. The chambers each communicate with the transducer to be evaluated and a standard pre-calibrated transducer the transducers being connected fluidly in parallel so that a pressure differential between air in the two chambers resulting from movement of the piston within the cylinder is communicated to both the transducer to be evaluated and the standard transducer, and the outputs of the transducers is observed and recorded.

  13. Pain in pressure ulcers.

    PubMed

    Reddy, Madhuri; Keast, David; Fowler, Evonne; Sibbald, R Gary

    2003-04-01

    Integrating pain management into a treatment paradigm for pressure ulcers can lead to improved outcomes. An approach to wound bed preparation that addresses the cause and patient-centered concerns--as well as local wound care factors of moisture balance, debridement, and bacterial balance--can be integrated with the Krasner model of chronic wound pain. The risk factors for pressure ulcers are well known, but pain may be an important contributor to immobility and the development of pressure ulcers. Pain is also an important signal of wound-related infections. Strategies must be developed to control the cyclic acute pain of dressing changes and the noncyclic acute pain of wound debridement. Spinal cord injured and elderly, cognitively impaired patients with pressure ulcers present special challenges in pain management. PMID:12856291

  14. High Blood Pressure

    MedlinePLUS

    ... pressure - a hypertension Google+ hangout in honor of World Hypertension Day 04/18/2013 Moderated by American ... live on April 5, 2013 in honor of World Health Day on Sunday, April 7. The NHLBI " ...

  15. Trielectrode capacitive pressure transducer

    NASA Technical Reports Server (NTRS)

    Coon, G. W.

    1975-01-01

    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.

  16. Osteomyelitis beneath pressure sores

    SciTech Connect

    Sugarman, B.; Hawes, S.; Musher, D.M.; Klima, M.; Young, E.J.; Pircher, F.

    1983-04-01

    Twenty-eight pressure sores were evaluated prospectively. Osteomyelitis was reported histologically in nine of 28 bones and pressure-related changes were reported in 14 bones. Roentgenograms suggested the presence of osteomyelitis in four instances of histologically proved osteomyelitis. Technetium Tc 99m medronate bone scans were highly sensitive, showing increased uptake in all cases of osteomyelitis; however, increased uptake also occurred commonly in uninfected bones due to pressure-related changes or other noninfectious causes. Cultures of bone biopsy samples usually disclosed anaerobic bacteria, gram-negative bacilli, or both. The diagnosis of osteomyelitis must be considered if a pressure sore does not respond to local therapy. If the technetium Tc 99m medronate uptake is increased in the involved area, or roentgenographic findings are abnormal, the diagnosis can only be made with certainty by histologic examination of bone. Antibacterial treatment should be selected based on the results of bone culture.

  17. Downhole pressure sensor

    NASA Technical Reports Server (NTRS)

    Berdahl, C. M.

    1980-01-01

    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.

  18. Stable hydraulic pressure regulator

    NASA Technical Reports Server (NTRS)

    Gold, H.

    1979-01-01

    Neither sensing line restrictors nor frictional dampers are required for stability. Analysis presents method by which stability margin, response, and droop magnitude can be incorporated during design of direct-acting hydraulic pressure regulators.

  19. Preventing Pressure Sores

    MedlinePLUS Videos and Cool Tools

    ... Injury 101 The Basics of Spinal Cord Injury Rehabilitation Preventing Pressure Sores Transition from Hospital to Home ... Cord Injury 101 The Basics of Pediatric SCI Rehabilitation Transitions for Children with Spinal Cord Injury What ...

  20. Air Under Pressure

    NSDL National Science Digital Library

    Integrated Teaching and Learning Program,

    Students are introduced to air masses, with an emphasis on the differences between and characteristics of high- versus low-pressure air systems. Students explore actual data by comparing maps of high- and low-pressure air masses to radar data showing where weather is occurring. Students also hear about weather forecasting instrumentation and how engineers work to improve these instruments for atmospheric measurements on Earth and in space.

  1. Pressure-Transducer Simulator

    NASA Technical Reports Server (NTRS)

    Simon, Richard A.

    1987-01-01

    Simulation circuit operates under remote, automatic, or manual control to produce electrical outputs similar to pressure transducer. Specific circuit designed for simulations of Space Shuttle main engine. General circuit concept adaptable to other simulation and control systems involving several operating modes. Switches and amplifiers respond to external control signals and panel control settings to vary differential excitation of resistive bridge. Output voltage or passive terminal resistance made to equal pressure transducer in any of four operating modes.

  2. Osteomyelitis beneath pressure sores

    Microsoft Academic Search

    B. Sugarman; S. Hawes; D. M. Musher; M. Klima; E. J. Young; F. Pircher

    1983-01-01

    Twenty-eight pressure sores were evaluated prospectively. Osteomyelitis was reported histologically in nine of 28 bones and pressure-related changes were reported in 14 bones. Roentgenograms suggested the presence of osteomyelitis in four instances of histologically proved osteomyelitis. Technetium Tc 99m medronate bone scans were highly sensitive, showing increased uptake in all cases of osteomyelitis; however, increased uptake also occurred commonly in

  3. High-pressure microfluidics

    NASA Astrophysics Data System (ADS)

    Hjort, K.

    2015-03-01

    When using appropriate materials and microfabrication techniques, with the small dimensions the mechanical stability of microstructured devices allows for processes at high pressures without loss in safety. The largest area of applications has been demonstrated in green chemistry and bioprocesses, where extraction, synthesis and analyses often excel at high densities and high temperatures. This is accessible through high pressures. Capillary chemistry has been used since long but, just like in low-pressure applications, there are several potential advantages in using microfluidic platforms, e.g., planar isothermal set-ups, large local variations in geometries, dense form factors, small dead volumes and precisely positioned microstructures for control of reactions, catalysis, mixing and separation. Other potential applications are in, e.g., microhydraulics, exploration, gas driven vehicles, and high-pressure science. From a review of the state-of-art and frontiers of high pressure microfluidics, the focus will be on different solutions demonstrated for microfluidic handling at high pressures and challenges that remain.

  4. Pressure Core Characterization

    NASA Astrophysics Data System (ADS)

    Santamarina, J. C.

    2014-12-01

    Natural gas hydrates form under high fluid pressure and low temperature, and are found in permafrost, deep lakes or ocean sediments. Hydrate dissociation by depressurization and/or heating is accompanied by a multifold hydrate volume expansion and host sediments with low permeability experience massive destructuration. Proper characterization requires coring, recovery, manipulation and testing under P-T conditions within the stability field. Pressure core technology allows for the reliable characterization of hydrate bearing sediments within the stability field in order to address scientific and engineering needs, including the measurement of parameters used in hydro-thermo-mechanical analyses, and the monitoring of hydrate dissociation under controlled pressure, temperature, effective stress and chemical conditions. Inherent sampling effects remain and need to be addressed in test protocols and data interpretation. Pressure core technology has been deployed to study hydrate bearing sediments at several locations around the world. In addition to pressure core testing, a comprehensive characterization program should include sediment analysis, testing of reconstituted specimens (with and without synthetic hydrate), and in situ testing. Pressure core characterization technology can be used to study other gas-charged formations such as deep sea sediments, coal bed methane and gas shales.

  5. Pressure fluctuating tool

    SciTech Connect

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

    1985-03-01

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

  6. Fullerene microcrystals under pressure

    NASA Astrophysics Data System (ADS)

    Tiago, Murilo L.; Reboredo, Fernando A.

    2008-03-01

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

  7. Fluctuating shells under pressure

    PubMed Central

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

    2012-01-01

    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

  8. High Blood Pressure and Women

    MedlinePLUS

    ... in life. Blood pressure during childbearing years Do birth control pills cause high blood pressure? Medical researchers have found that birth control pills increase blood pressure in some women. It's ...

  9. Response of pre-pressurized reinforced plates under blast loading

    Microsoft Academic Search

    R. L. Veldman; J. Ari-Gur; C. Clum

    2008-01-01

    The effects of pre-pressurization on blast-loaded reinforced rectangular aluminum plates were studied experimentally. Rectangular clamped plates with rivet-attached stiffeners were used as a basic model of the fuselage skin of a commercial aircraft. Both non-pressurized and pre-pressurized plates (static pressure of 41.4kPa) were considered to simulate the typical in-flight loads experienced by a commercial aircraft due to cabin pressurization. This

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

    Microsoft Academic Search

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

    1986-01-01

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

  11. Optically interrogated MEMS pressure sensor array

    NASA Astrophysics Data System (ADS)

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

    2012-04-01

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

  12. Questions and Answers about High Blood Pressure

    MedlinePLUS

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

  13. Automated Blood Pressure Measurement

    NASA Technical Reports Server (NTRS)

    1978-01-01

    The Vital-2 unit pictured is a semi-automatic device that permits highly accurate blood pressure measurement, even by untrained personnel. Developed by Meditron Instrument Corporation, Milford, New Hampshire, it is based in part on NASA technology found in a similar system designed for automatic monitoring of astronauts' blood pressure. Vital-2 is an advancement over the familiar arm cuff, dial and bulb apparatus customarily used for blood pressure checks. In that method, the physician squeezes the bulb to inflate the arm cuff, which restricts the flow of blood through the arteries. As he eases the pressure on the arm, he listens, through a stethoscope, to the sounds of resumed blood flow as the arteries expand and contract. Taking dial readings related to sound changes, he gets the systolic (contracting) and diastolic (expanding) blood pressure measurements. The accuracy of the method depends on the physician's skill in interpreting the sounds. Hospitals sometimes employ a more accurate procedure, but it is "invasive," involving insertion of a catheter in the artery.

  14. Clutch pressure control apparatus

    SciTech Connect

    Koori, Y.; Mitsui, T.

    1989-01-24

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

  15. Dynamic Pressure Probes Developed for Supersonic Flow-Field Measurements

    NASA Technical Reports Server (NTRS)

    Porro, A. Robert

    2001-01-01

    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.

  16. Comparison of functional residual capacity and static compliance of the respiratory system during a positive end-expiratory pressure (PEEP) ramp procedure in an experimental model of acute respiratory distress syndrome

    Microsoft Academic Search

    Bernard Lambermont; Alexandre Ghuysen; Nathalie Janssen; Philippe Morimont; Gary Hartstein; Paul Gerard; Vincent D'Orio

    2008-01-01

    INTRODUCTION: Functional residual capacity (FRC) measurement is now available on new ventilators as an automated procedure. We compared FRC, static thoracopulmonary compliance (Crs) and PaO2 evolution in an experimental model of acute respiratory distress syndrome (ARDS) during a reversed, sequential ramp procedure of positive end-expiratory pressure (PEEP) changes to investigate the potential interest of combined FRC and Crs measurement in

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

    Microsoft Academic Search

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

    2004-01-01

    This article reports the measurements of time-resolved heat transfer rate and time-resolved static pressure that have been made on the over-tip casing of a transonic axial-flow turbine operating at flow conditions that are representative of those found in modern gas turbine engines. This data is discussed and analysed in the context of explaining the physical mechanisms that influence the casing

  18. A novel high pressure tool: the solvation pressure of liquids

    NASA Astrophysics Data System (ADS)

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

    2004-04-01

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

  19. High Blood Pressure

    NSDL National Science Digital Library

    American Association for the Advancement of Science (; )

    2004-01-01

    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.

  20. A Microwave Pressure Sounder

    NASA Technical Reports Server (NTRS)

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

    1978-01-01

    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.

  1. Pressure suppression containment system

    DOEpatents

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

    1994-03-15

    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.

  2. Pressure suppression containment system

    DOEpatents

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

    1994-03-15

    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.

  3. Proximal airway pressure monitoring in the neonatal ICU.

    PubMed

    Mayock, D E; Tremblay, L

    1984-08-01

    The static and dynamic responses of diaphragm-type pressure manometers currently used with manual ventilation in the neonatal ICU were determined at different pressures and frequencies. Using a precalibrated transducer attached to a closed-loop system, the manometer peak pressure was adjusted to 15, 20, 25, and 30 cm H2O, first for static measurements and then again while the frequency was increased from 20 to 200 breath/min in increments of 20. Most manometers with inlet flow-restricting devices built into the manometer or attached to the connection system in a ventilator significantly underestimated the delivered pressure as the peak inflation pressure and frequency were increased. In those manometers without inlet flow restrictors the correlation between transducer pressure and observed manometer pressure was close. Diaphragm-type pressure manometers with inlet flow-restricting devices may substantially underestimate the delivered proximal airway pressure when incorporated into neonatal manual ventilation equipment. PMID:6589117

  4. Plating under reduced pressure

    SciTech Connect

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

    1992-06-01

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

  5. Blood Pressure Control

    NASA Technical Reports Server (NTRS)

    1992-01-01

    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.

  6. Submarine Coaxial Cable Pressure Characteristics

    Microsoft Academic Search

    K. Aida; M. Aiki

    1978-01-01

    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

  7. Saltstone Osmotic Pressure

    SciTech Connect

    Nichols, Ralph L.; Dixon, Kenneth L.

    2013-09-23

    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

  8. System for calibrating pressure transducer

    NASA Technical Reports Server (NTRS)

    Rollins, G. N. (inventor)

    1973-01-01

    A system for calibrating a pressure transducer which has a reference portion and an active portion is reported. A miniature selector valve is positioned immediately adjacent the pressure transducer. A reference pressure, known pressure, and unknown pressure can be selectively admitted to the active side of the pressure transducer by the selector valve to enable calibration of the transducer. A valve admits pressure to the selector valve which has a piston and floating piston arrangement which allows proper selection with very small linear movement.

  9. Dual pressure displacement control system

    SciTech Connect

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

    1988-02-02

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

  10. 30 CFR 18.98 - Enclosures, joints, and fastenings; pressure testing.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...joints, and fastenings; pressure testing. (a) Cast...withstand a minimum internal pressure of 150 pounds per square inch (gage). Castings shall be free from blowholes...a peak dynamic or static pressure of 150 pounds per...

  11. AIR-BLAST PHENOMENA IN THE HIGH-PRESSURE REGION

    Microsoft Academic Search

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

    1960-01-01

    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 ;

  12. Optical Study of Lanthanide Metals at High Pressure

    Microsoft Academic Search

    R. G. Kraus; E. D. Emmons; J. S. Thompson; A. M. Covington

    2007-01-01

    We are currently investigating the pressure dependence of the photoluminescence spectra of lanthanides, including Gadolinium metal. This investigation is conducted at hydrostatic pressures up to 10 gigapascals. Static pressure is obtained using a four post diamond anvil cell. The photoluminescence is excited with a low power (5 mW) continuous wave Argon ion gas laser, and the spectrum is collected using

  13. Microscale pressure fluctuations in a mature deciduous forest

    Microsoft Academic Search

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

    1983-01-01

    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

  14. Cellular Pressure-Actuated Joint

    NASA Technical Reports Server (NTRS)

    McGuire, John R.

    2003-01-01

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

  15. Fiber Optic Pressure Sensor Design Considerations And Evaluation

    NASA Astrophysics Data System (ADS)

    Hong, LiLi; Nara, Andren R.; Prohaska, Otto J.

    1989-08-01

    A new type of fiber optic pressure transducer has been developed and tested for biomedical application. It consists of two parts: a pressure-sensing membrane and a fiber optic displacement transducer which is based on the light intensity loss caused by angular misalignment between two fibers. The light intensity change is registered by a photodiode. The pressure transducer has been evaluated for static and dynamic pressure measurements. Not only does it have adequate linearity and frequency response and is safe and small in size, but it also may be an attractive device for designing catheters for multiple site static pressure detection.

  16. Pressure melting of ice

    Microsoft Academic Search

    Thomas A. Weber; Frank H. Stillinger

    1984-01-01

    A 250-molecule ice Ih crystallite has been melted at a pressure of about 2 kbars using molecular dynamics computer simulation. The ST2 potential has been used to represent molecular interactions. Melting was observed to begin at the crystallite surface and to proceed inward until the entire crystal was converted to an amorphous droplet. The melting point was found to be

  17. Reactor pressure vessel nozzle

    SciTech Connect

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

    1994-01-01

    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.

  18. Reactor pressure vessel nozzle

    DOEpatents

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

    1994-10-04

    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.

  19. Characteristics of pressure waves

    NASA Technical Reports Server (NTRS)

    1977-01-01

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

  20. Optimisation of compound pressure

    Microsoft Academic Search

    G. H. Majzoobi; A. Ghomi

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

  1. The Blood Pressure \\

    Microsoft Academic Search

    Cornel Pater

    2005-01-01

    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

  2. High blood pressure - infants

    MedlinePLUS

    ... click may be heard if a bicuspid aortic valve occurs with the coarctation. Other tests in infants with high blood pressure will try to find the cause of the problem. Such tests may include: A special type of x-ray that uses a dye to look at ...

  3. Pressure in Fluids

    NSDL National Science Digital Library

    2008-02-07

    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.

  4. 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....

  5. Negative pressure wound therapy

    Microsoft Academic Search

    MICHAEL KIRBY

    2010-01-01

    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

  6. Negative pressure wound therapy

    Microsoft Academic Search

    Michael Kirby

    2007-01-01

    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

  7. Arterial Pressure Analog.

    ERIC Educational Resources Information Center

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

    1980-01-01

    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…

  8. Pressure and Stoichiometry

    NASA Astrophysics Data System (ADS)

    Roser, Charles E.; McCluskey, Catherine L.

    1999-05-01

    This experiment determines the stoichiometry of the reaction of a carbonate or hydrogen carbonate and HCl by measuring the pressure of the CO2 produced using a Vernier pressure sensor, Texas Instruments CBL interface, and a TI-82/83 graphing calculator. Various amounts of the carbonate are reacted with a constant amount of HCl. The change in pressure in a constant-volume (20-oz soda bottle) system is measured and plotted against the mass of the carbonate. The mass of the carbonate that is needed to react with all the HCl is determined from the graph. The mole ratio between the carbonate and HCl in the reaction mixture is determined and used to write a balanced equation for the reaction. Different carbonates and hydrogen carbonates have been used successfully. The advantages of this procedure are that students can run a large number of samples (since each sample requires only 100 s of data collection time), develop an understanding of the concept of a limiting reactant, and develop an understanding of the relationship between the amount of gas produced by a reaction and the pressure in the reaction container. The experiment incorporates the use of technology, graphing, and data analysis and is appropriate for an introductory chemistry laboratory. The directions can be easily modified to use computers and other graphing calculator probe systems.

  9. High-temperature fiber optic pressure sensor

    NASA Technical Reports Server (NTRS)

    Berthold, J. W.

    1984-01-01

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

  10. Pressure natriuresis and the renal control of arterial blood pressure.

    PubMed

    Ivy, Jessica R; Bailey, Matthew A

    2014-09-15

    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

  11. Pressurized burner test facility

    SciTech Connect

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

    1993-09-01

    The US Department of Energy`s METC has recently completed construction and commissioning of a new high-pressure combustion research facility. Utilities servicing the facility enable combustion tests at scales up to 3 MW (10 MM Btu/h) and pressures in excess of 3000 kPa (30 atm). These include a preheated, high-pressure air supply that can deliver up to 1.7 kg/s (3.7 lbs/s) of combustion air, and a high-pressure, natural gas compressor that can deliver 0.8 kg/s (.19 lbs/s). In the summer of 1994 METC`s syngas generator is scheduled to come on line, at which time combustion tests on a range of fuel gases from low to medium to high heating values will be possible. The syngas generator will simulate a range of fuel gas compositions characteristic of coal gasification product streams. As part of the combustion facility, a high-pressure burner test facility is currently being constructed to support the development of gas turbine combustion systems fired on natural gas and coal-derived gaseous fuels containing fuel-bound nitrogen. The facility, illustrated in Figure 1, is a 61-centimeter (24-inch) diameter, refractory-lined vessel of modular construction, offering the flexibility to test a variety of NO{sub x} control concepts. Burner test modules are sandwiched between gas inlet and sampling plenums with a maximum combustion test zone of 2.2 m (90 inches) in length. Modules are custom designed for specific burners.

  12. Negative pressure device for intra-abdominal pressure reduction

    NASA Astrophysics Data System (ADS)

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

    2007-11-01

    A device that generates negative extra-abdominal pressure (ABDOPRE) for treatment of patients with high intra-abdominal pressure was developed. It includes pressure sensors for transducing intra-abdominal pressure through an intra-vesical catheter and negative pressure in the vacuum bell which is placed over the abdomen. By means of a control system, a pattern for reducing IAP is set, according to a clinical protocol. The external negative pressure is generated using a vacuum pump connected to the bell. The system registers the values of interest for the medical history. The system is being tested over ICU patients, registering a satisfactory IAP reduction.

  13. 14 CFR 23.841 - Pressurized cabins.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ...airplane must be able to maintain a cabin pressure altitude of not more than 15...and indicators, for controlling cabin pressure: (1) Two pressure relief...the pressure differential, the cabin pressure altitude, and the rate of...

  14. 14 CFR 23.841 - Pressurized cabins.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ...airplane must be able to maintain a cabin pressure altitude of not more than 15...and indicators, for controlling cabin pressure: (1) Two pressure relief...the pressure differential, the cabin pressure altitude, and the rate of...

  15. 14 CFR 23.841 - Pressurized cabins.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ...airplane must be able to maintain a cabin pressure altitude of not more than 15...and indicators, for controlling cabin pressure: (1) Two pressure relief...the pressure differential, the cabin pressure altitude, and the rate of...

  16. 14 CFR 23.841 - Pressurized cabins.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ...airplane must be able to maintain a cabin pressure altitude of not more than 15...and indicators, for controlling cabin pressure: (1) Two pressure relief...the pressure differential, the cabin pressure altitude, and the rate of...

  17. 14 CFR 23.841 - Pressurized cabins.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ...airplane must be able to maintain a cabin pressure altitude of not more than 15...and indicators, for controlling cabin pressure: (1) Two pressure relief...the pressure differential, the cabin pressure altitude, and the rate of...

  18. Pressure activated diaphragm bonder

    DOEpatents

    Evans, L.B.; Malba, V.

    1997-05-27

    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.

  19. Consider nonrepairable pressure transmitters

    SciTech Connect

    Swanson, R.M. (Rosemount, Inc., Eden Prairie, MN (US))

    1989-07-01

    Electronic pressure and differential pressure transmitters in oil and gas industries may fall into three tiers of product offerings based on performance and material selection. The movement toward electronic billing of custody transfer has focused attention on two of these tiers: the high performance smart'' transmitters and conventional analog devices with enhanced performance capabilities. When real dollars are changing hands, as in custody transfer situations, performance is paramount. However, for many other applications, the performance found in this equipment may not be required. The author discusses how consideration might be given to the third-tier offering: the low-cost, nonrepairable transmitter. In doing so, features and benefits should be weighed against cost of ownership.

  20. Exhaust back pressure reducer

    SciTech Connect

    Eller, H.E.

    1987-05-19

    This patent describes an exhaust back pressure reducer for the internal combustion engine of a tractor for pulling a trailer. The tractor has a cab. An air deflector on the top of the cab deflect air over the top of the trailer as the tractor pulls the trailer over the road, and it includes exhaust system for the engine. The reducer comprises: means at the top of the air deflector on the top of the cab for aspirating gas from the engine exhaust system to reduce the exhaust back pressure on the engine. The aspirating means is positioned for flow therepast of air relative to the air deflector as the tractor travels forward. The aspirating means is ported for suctioning gas therefrom by the air flowing therepast.

  1. High pressure furnace

    DOEpatents

    Morris, D.E.

    1993-09-14

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

  2. Pressure suppression system

    DOEpatents

    Gluntz, D.M.

    1994-10-04

    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.

  3. Pressure suppression system

    DOEpatents

    Gluntz, Douglas M. (San Jose, CA)

    1994-01-01

    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.

  4. High pressure oxygen furnace

    DOEpatents

    Morris, Donald E. (Kensington, CA)

    1992-01-01

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

  5. Columbus pressurized module verification

    NASA Technical Reports Server (NTRS)

    Messidoro, Piero; Comandatore, Emanuele

    1986-01-01

    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.

  6. Casual Blood Pressure Methodology

    Microsoft Academic Search

    Lavjay Butani; Bruce Z. Morgenstern

    \\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)

  7. Atmospheric Pressure Glow Discharges

    SciTech Connect

    Graham, W. G.; Nersisyan, G. [International Research Centre for Experimental Physics, Queens University Belfast, BT7 1NN, Northern Ireland (United Kingdom)

    2006-12-01

    Their relative engineering simplicity, plasma uniformity and chemistry make Atmospheric Pressure Glow Discharges (APGD) very attractive for plasma processing applications. Here some of the basic characteristics of glow discharges are introduced. The basic dielectric barrier discharge and how it can be operated in a uniform glow rather filamentary mode is described. Electrical and laser-based measurements that throw light on the underlying physics of APGDs are presented, along with a model which seeks to explore the plasma chemistry of these discharges.

  8. Pressure Garment Subsystem Roadmap

    NASA Technical Reports Server (NTRS)

    Ross, Amy J.

    2010-01-01

    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.

  9. Oscillation pressure device for dynamic calibration of pressure transducers

    NASA Technical Reports Server (NTRS)

    Hess, Robert W. (Inventor); Davis, William T. (Inventor); Davis, Pamela A. (Inventor)

    1987-01-01

    Method and apparatus for obtaining dynamic calibrations of pressure transducers. A calibration head (15), a flexible tubing (23) and a bellows (20) enclose a volume of air at atmospheric pressure with a transducer (11) to be calibrated subject to the pressure inside the volume. All of the other apparatus in the drawing apply oscillations to bellows (20) causing the volume to change thereby applying oscillating pressures to transducer (11) whereby transducer (11) can be calibrated.

  10. Oil pressure transducer

    SciTech Connect

    Betterton, J.T.; Glover, A.H.; Griffin, R.L.; Kerstiens, A.J.

    1989-02-21

    An improved fluid pressure transducer is described comprising: generally hollow first and second housing members attached together in an end to end manner; a diaphragm member with a peripheral edge and a flexible mid portion. The edge is attached between the housings and the mid portion having first and second surfaces. The first surface is exposed to pressurized fluid and the second surface is exposed to atmosphere thereby generating a net pressure force on the mid portion; a piston member having an end portion operatively attached to the mid portion, an integral tubular portion of the piston extending within the second housing, whereby the piston is supported for axial reciprocation in the interior of the second housing corresponding to the movements of the mid portion; the second housing having an outwardly extending end wall which defines an end recess; a terminal support member insertably adjustable within the recess and having an elongated central portion which extends generally co-axially into the interior of the second housing; an electrical circuit board attached to the terminal support member and extending in the axial direction with respect to the piston member and through the interior of the tubular piston, an electrical resistance grid on one exposed surface of the circuit board.

  11. High pressure ratio turbocharger

    SciTech Connect

    Woollenweber, W.E.

    1991-06-25

    This patent describes a turbocharger system for an internal combustion engine. It comprises means forming a turbine adapted to be driven by exhaust gas from an internal combustion engine comprising: a turbine wheel having a central core and outwardly extending vanes, the turbine wheel being rotatable about a central axis; a meridionally divided volute for exhaust gas surrounding the turbine wheel, the meridionally divided volute including a divider wall defining first and second volute passageways with openings at the turbine wheel; means forming a high-pressure compressor driven by the turbine means, the high-pressure compressor comprising: rotating compressor blades, the compressor blades adapted to be driven in rotation about the central axis by the turbine means to deliver a flow of air at high pressures for an internal combustion engine, and blades being moveable about longitudinal axes generally transverse to the central axis to impart positive or negative pre-whirl motion to the air leaving the stator blades prior to entering the rotating blades of the compressor stage; closure means for providing a flow of engine exhaust gas from one of the first and second volute passageways into the turbine wheel; and a control means for operating the closure means and the stator blades in synchronization.

  12. [Normal pressure hydrocephalus].

    PubMed

    Espinosa, J

    1991-09-01

    We studied the clinical records of 18 patients (11 female and 7 male), from 42-83 years old (average 66.1) who were operated for Normal Pressure Hydrocephalus. The etiology was idiopathic in 9 (50%), post-subarachnoid hemorrhage in 6 patients (33.3%), post-cerebral trauma in 2 (11.1%) and post-meningitis in 1. The patients were divided in 4 categories according to their symptoms, as follows: Group A: 9 patients (50%) with dementia, ataxia and incontinence. Group B: 1 patient (5.6%) with dementia-ataxia. Group C: 4 patients (22.2%) with ataxia and incontinence. Group D: 4 patients (22.2%) with ataxia only. 6 patients had a ventriculo peritoneal shunt, and 12 had a ventriculo-atrial shunt placed. All received a Hakim valve of low, medium or high pressure, according to the pre-op ventricular pressure. According to Stein and Langfitt scale for recovery 12 patients (66%) improved and 6 (33.3%) did not change. None was worse. There were no complications. PMID:1767037

  13. A pressure controller for wind tunnel pressure systems

    Microsoft Academic Search

    J. S. Carter

    1993-01-01

    Pressure transducers are used to provide flight performance and test conditions information during wind tunnel testing. Calibration is required on a scheduled basis for every pressure transducer used to test flight vehicles at Arnold Engineering Development Center, Arnold Air Force Base, Tennessee. A pressure calibration device must be traceable to the National Institute of Standards and Technology (NIST), provide manual

  14. Hybrid Inflatable Pressure Vessel

    NASA Technical Reports Server (NTRS)

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

    2004-01-01

    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.

  15. Blood Pressure Monitoring at Home

    MedlinePLUS

    ... popular blood-pressure measuring device. The blood pressure measurement is easy to read, because the numbers are shown on a screen. Some electronic monitors also have a paper printout that gives ...

  16. Helping Teens Resist Sexual Pressure

    MedlinePLUS

    Healthy Children > Ages & Stages > Teen > Dating & Sex > Helping Teens Resist Sexual Pressure Ages & Stages Listen Español Text Size Email Print Share Helping Teens Resist Sexual Pressure Article Body Teens are more ...

  17. Economics of Steam Pressure Reduction

    E-print Network

    Sylva, D. M.

    ECONOMICS OF STEAM PRESSURE REDUCTION Dennis M. Sylva AT&T Technology, Reading Works Reading, Pennsylvania Economics of Steam Pressure Reduction is a technical paper that addresses the operating and! economic advantages associated...

  18. Pressure-Sealing Optical Coupling

    NASA Technical Reports Server (NTRS)

    Irvin, Timothy B.; French, Richard E.

    1988-01-01

    Light signals passed out of high-pressure cryogenic environment. Optical coupling passes signals in fiber-optic channels across pressure-and-temperature barrier. Coupling made in different configurations and modified to suit requirements of different cryogenic instrumentation systems.

  19. Flow-compensating pressure regulator

    NASA Technical Reports Server (NTRS)

    Baehr, E. F.

    1979-01-01

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

  20. High Blood Pressure Fact Sheet

    MedlinePLUS

    ... this? Submit What's this? Submit Button Related CDC Web Sites Heart Disease Stroke High Blood Pressure Salt ... Prevent and Control Chronic Diseases Million Hearts® WISEWOMAN Web Sites with More Information About High Blood Pressure ...

  1. 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 ...

  2. Semiconductor pressure-pulse sensor

    Microsoft Academic Search

    V. Stankevi?; ?. Šimkevi?ius

    1995-01-01

    The use of a semiconductor pressure sensor based on AlGaAs thin films to measure shock-wave pressures in lithotripters is described. The selection of an optimal thickness of encapsulant on the face of the pressure-sensitive chip enables a satisfactory durability and dynamic accuracy of the sensors to be obtained. Pressure sensors with a diameter of 1.3 mm have a sensitivity of

  3. Electronically Variable Pressure Regulator (EVPR)

    Microsoft Academic Search

    R. H. Reinicke; R. O. Nelson; E. Hurlbert

    1989-01-01

    A new programmable electronically variable pressure regulator (EVPR) concept accurately controls the local outlet or remote system pressure. It uses an integral pulse width modulated rare earth permanent magnet motor operating in response to redundant pressure transducer feedback signals. The EVPR is a simple single stage device that does not use dynamic seals or pilot valving. Conversion of partial revolution

  4. Calculating Pressures In Electrochemical Cells

    NASA Technical Reports Server (NTRS)

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

    1992-01-01

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

  5. Dual rate pressure relief valve

    NASA Technical Reports Server (NTRS)

    Steeneken, J.

    1968-01-01

    Pressure relief valve vents at a slow bleed rate at one pressure level and at a higher bleed rate at a higher pressure level. The value housing contains a sleeve, inlet port, outlet port, an orifice, a ball and seat arrangement, and a belleville spring diaphragm.

  6. Constant-Pressure Hydraulic Pump

    NASA Technical Reports Server (NTRS)

    Galloway, C. W.

    1982-01-01

    Constant output pressure in gas-driven hydraulic pump would be assured in new design for gas-to-hydraulic power converter. With a force-multiplying ring attached to gas piston, expanding gas would apply constant force on hydraulic piston even though gas pressure drops. As a result, pressure of hydraulic fluid remains steady, and power output of the pump does not vary.

  7. Abnormal pressure in hydrocarbon environments

    USGS Publications Warehouse

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

    1998-01-01

    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.

  8. Blood Pressure Medicine: Special Instructions

    E-print Network

    Bandettini, Peter A.

    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

  9. Apparatus for absolute pressure measurement

    NASA Technical Reports Server (NTRS)

    Hecht, R. (inventor)

    1969-01-01

    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.

  10. Hydrostatic pressure mimics gravitational pressure in characean cells

    NASA Technical Reports Server (NTRS)

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

    1992-01-01

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

  11. Experimental studies of ratcheting of pressurized elbow

    SciTech Connect

    Kobayashi, Hiroe; Yokoi, Ryoh; Fujiwaka, Tatsuya [Ishikawajima-Harima Heavy Industries Co., Ltd., Yokohama (Japan)

    1995-11-01

    The piping systems in nuclear power plants are subjected to both static sustained loads such as pressure or dead weight and dynamic loads such as seismic events. Under the severe seismic condition, it is well known that ratcheting occurs in the weak piping element such as elbow. Dynamic experiments and FEM analysis are conducted on a pressurized elbow to clarify the mechanical ratchet phenomena in the seismic event. Dynamic experiments runs on 100A Schedule 80 and 550A Schedule 20 304 type stainless steel elbow. The dynamic loads are experimentally given to the piping model by the shake table. Nonlinear FEM analysis runs on the 550A model using shell elements. Analytical result of the hoop ratcheting at the top of the elbow is in good agreement with the experimental result. Parametric analysis for some pressure and dynamic load levels are performed in order to clarify the condition for preventing the mechanical ratcheting phenomena on pressurized elbow.

  12. Unibody Composite Pressurized Structure

    NASA Technical Reports Server (NTRS)

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

    2013-01-01

    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.

  13. Chromium at High Pressure

    NASA Astrophysics Data System (ADS)

    Jaramillo, Rafael

    2012-02-01

    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).

  14. Hypertension (High Blood Pressure)

    NSDL National Science Digital Library

    Patient Education Institute

    This patient education program discusses hypertension including the causes, complications, risk factors, diagnosis, and management of the disease. It also explains what blood pressure is. This resource is a MedlinePlus Interactive Health Tutorial from the National Library of Medicine, designed and developed by the Patient Education Institute. NOTE: This tutorial requires a special Flash plug-in, version 4 or above. If you do not have Flash, you will be prompted to obtain a free download of the software before you start the tutorial. You will also need an Acrobat Reader, available as a free download, in order to view the Reference Summary.

  15. Resumming the pressure

    E-print Network

    Anton Rebhan

    1998-09-21

    The convergence properties of the resummed thermal perturbation series for the thermodynamic pressure are investigated by comparison with the exact results obtained in large-N phi^4 theory and possibilities for improvements are discussed. By going beyond conventional resummed perturbation theory, renormalization has to be carried out nonperturbatively yet consistently. This is exemplified in large-N phi^4_4 and in a special large-N \\phi^3_6 model that mimics QED in the limit of large flavour number.

  16. Effects of pre-pressurization on blast response of clamped aluminum plates

    Microsoft Academic Search

    R. L. Veldman; J. Ari-Gur; C. Clum; A. DeYoung; J. Folkert

    2006-01-01

    The effects of static pre-pressurization on the blast response of square aluminum plates were studied both experimentally and numerically. Static pre-pressurization values in the range of 0–62.1kPa (0–9.0psi) were chosen to represent in-flight loads experienced by the outer skin of a commercial aircraft fuselage due to cabin pressurization. Experimentally, a vacuum vessel system was used to apply a static pressure

  17. High-pressure neutron diffraction

    SciTech Connect

    Xu, Hongwu [Los Alamos National Laboratory

    2011-01-10

    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.

  18. Assessment of fiber optic pressure sensors

    SciTech Connect

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

    1995-04-01

    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.

  19. Airway obstruction with cricoid pressure.

    PubMed

    Hartsilver, E L; Vanner, R G

    2000-03-01

    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

  20. High pressure capillary connector

    DOEpatents

    Renzi, Ronald F.

    2005-08-09

    A high pressure connector capable of operating at pressures of 40,000 psi or higher is provided. This connector can be employed to position a first fluid-bearing conduit that has a proximal end and a distal end to a second fluid-bearing conduit thereby providing fluid communication between the first and second fluid-bearing conduits. The connector includes (a) an internal fitting assembly having a body cavity with (i) a lower segment that defines a lower segment aperture and (ii) an interiorly threaded upper segment, (b) a first member having a first member aperture that traverses its length wherein the first member aperture is configured to accommodate the first fluid-bearing conduit and wherein the first member is positioned in the lower segment of the internal fitting assembly, and (c) a second member having a second member aperture that traverses its length wherein the second member is positioned in the upper segment of the fitting assembly and wherein a lower surface of the second member is in contact with an upper surface of the first member to assert a compressive force onto the first member and wherein the first member aperture and the second member aperture are coaxial.

  1. Ratchetting in pressurized pipes

    NASA Astrophysics Data System (ADS)

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

    1994-04-01

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

  2. Combustor oscillation pressure stabilizer

    SciTech Connect

    Gemmen, R.S.; Richards, G.A.; Yip, M.T.J.; Robey, E.; Cully, S.R.; Addis, R.E.

    1996-12-31

    In accordance with the objective of the present invention, the active control of unsteady combustion induced oscillations in a combustion chamber fired by a suitable fuel and oxidizer mixture, such as a hydrocarbon fuel and air mixture, is provided by restructuring and moving the position of the main flame front and thereby increasing the transport time and displacing the pressure wave further away from the in-phase relationship with the periodic heat release. The restructuring and repositioning of the main flame are achieved by utilizing a pilot flame which is pulsed at a predetermined frequency corresponding to less than about one-half the frequency of the combustion oscillation frequency with the duration of each pulse being sufficient to produce adequate secondary thermal energy to restructure the main flame and thereby decouple the heat release from the acoustic coupling so as to lead to a reduction in the dynamic pressure amplitude. The pulsating pilot flame produces a relatively small and intermittently existing flame front in the combustion zone that is separate from the oscillating main flame front but which provides the thermal energy necessary to effectively reposition the location of the oscillating main flame front out of the region in the combustion zone where the acoustic coupling can occur with the main flame and thereby effectively altering the oscillation-causing phase relationship with the heat of combustion.

  3. Pressure polymerization of polyester

    DOEpatents

    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

    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.

  4. Pressure, Force, Muscles and Massage

    NSDL National Science Digital Library

    BEGIN:VCARD VERSION:2.1 FN:Kristin Shields N:Shields; Kristin ORG:Vanden High School REV:2005-04-12 END:VCARD

    1995-06-30

    The human body is constantly being subjected to external forces. The relation between force and pressure is straightforward. The more force exerted, the greater the pressure, but the effect of area on pressure is somewhat more subtle. Through the process of massage students apply their understanding of forces and pressures to enhance the relaxation of their lab partner's forearm. A proper understanding of the concept of pressure is essential to an understanding of most areas of physiology. This activity provides students with a feeling for what pressure is and how it is related to force and area. Students determine the pressure exerted on the bottoms of their feet under a variety of circumstances. In each case, the force exerted is body weight. But the area over which that force is exerted differs, depending on whether one is standing on two feet, one foot or tiptoe (one-foot.)

  5. The vapor pressures of explosives

    SciTech Connect

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

    2013-01-05

    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.

  6. Optical calibration of pressure sensors for high pressures and temperatures

    SciTech Connect

    Goncharov, A F; Gregoryanz, E; Zaug, J M; Crowhurst, J C

    2004-10-04

    We present the results of Raman scattering measurements of diamond ({sup 12}C) and of cubic boron nitride (cBN), and fluorescence measurements of ruby, Sm:YAG, and SrB{sub 4}O{sub 7}:Sm{sup 2+} in the diamond anvil cell (DAC) at high pressures and temperatures. These measurements were accompanied by synchrotron x-ray diffraction measurements on gold. We have extended the room-temperature calibration of Sm:YAG in a quasihydrostatic regime up to 100 GPa. The ruby scale is shown to systematically underestimate pressure at high pressures and temperatures compared with all other sensors. On this basis, we propose a new high-temperature ruby pressure scale that should be valid to at least 100 GPa and 850 K. Historically, the accurate determination of pressure at high temperature and ultrahigh pressure has been extremely difficult. In fact, the lack of a general pressure scale nullifies, to a significant extent, the great innovations that have been made in recent years in DAC experimental techniques [1]. Now, more than ever a scale is required whose accuracy is comparable with that of the experimental data. Since pressure in the DAC is dependent on temperature (due to thermal pressure and also to changes in the properties of the materials that constitute the DAC) such a scale requires quantitative, and separate measurements of pressure and temperature.

  7. Thermodynamic equilibrium at heterogeneous pressure

    NASA Astrophysics Data System (ADS)

    Vrijmoed, Johannes C.; Podladchikov, Yuri Y.

    2014-05-01

    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).

  8. Advanced strain-gage pressure transducer

    NASA Astrophysics Data System (ADS)

    Delmonte, J.; Albaugh, H.; Baker, D. S.; Spence, C. B.

    1983-03-01

    Gould, Inc. has developed new strain gage deposition and lead wire attachment processes that have shown significant promise for improved accuracy, higher reliability, and lower cost when applied to strain gage pressure transducers now being used in gas turbine control and diagnostic systems. This report summarizes work efforts to experimentally identify and to validate, via bench tests, the benefits of these new fabrication processes. The results of static accuracy, temperature and pressure cycling, acceleration, vibration, thermal and mechanical shock, and humidity testing are discussed.

  9. Pressure Measurement Sensor

    NASA Technical Reports Server (NTRS)

    1997-01-01

    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.

  10. High pressure mechanical seal

    NASA Technical Reports Server (NTRS)

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

    1996-01-01

    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.

  11. Pressurized continuous chromatography

    SciTech Connect

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

    1980-04-01

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

  12. Cradle and pressure grippers

    DOEpatents

    Muniak, John E. (New York, NY)

    2001-01-01

    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.

  13. Gas/oil capillary pressure at chalk at elevated pressures

    SciTech Connect

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

    1995-09-01

    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.

  14. 14 CFR 23.843 - Pressurization tests.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... The complete pressurized cabin, including doors, windows...and valves, must be tested as a pressure vessel for the pressure differential specified in § 23...of the positive and negative pressure differential valves, and...

  15. 14 CFR 23.843 - Pressurization tests.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... The complete pressurized cabin, including doors, windows...and valves, must be tested as a pressure vessel for the pressure differential specified in § 23...of the positive and negative pressure differential valves, and...

  16. 14 CFR 23.843 - Pressurization tests.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... The complete pressurized cabin, including doors, windows...and valves, must be tested as a pressure vessel for the pressure differential specified in § 23...of the positive and negative pressure differential valves, and...

  17. 14 CFR 23.843 - Pressurization tests.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... The complete pressurized cabin, including doors, windows...and valves, must be tested as a pressure vessel for the pressure differential specified in § 23...of the positive and negative pressure differential valves, and...

  18. 14 CFR 23.843 - Pressurization tests.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... The complete pressurized cabin, including doors, windows...and valves, must be tested as a pressure vessel for the pressure differential specified in § 23...of the positive and negative pressure differential valves, and...

  19. High pressure, high temperature transducer

    NASA Technical Reports Server (NTRS)

    Vrolyk, John J. (Inventor)

    1977-01-01

    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.

  20. Transitional wall pressure fluctuations on axisymmetric bodies.

    PubMed

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

    2008-11-01

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

  1. Practical Management of Pressure Sores

    PubMed Central

    Jordan, John M.

    1992-01-01

    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

  2. High-Pressure Transducer Package

    NASA Technical Reports Server (NTRS)

    Wamstad, D.; Glenn, M.

    1987-01-01

    Enclosure for silicon device ensures accurate measurements of cryogenic liquids. Package holds silicon sensor in uniform compression around periphery and helps ensure accurate, stable, and repeatable pressure measurements. Mounting assembly housed in package of stainless steel. Materials selected for equality of thermal expansion and for pressure-sealing properties. Besides its high-pressure, low-temperature characteristics, package withstands vibrations as severe as 400 times standard gravitational acceleration at 0 to 2,000 Hz.

  3. Powder aerosols generated by accidents: pressurized release experiments.

    PubMed

    Sutter, S L

    1983-06-01

    Safety assessments and environmental impact statements for facilities require an estimation of airborne releases. Aerosols generated by accidents are being investigated to develop the source terms for these releases. A severe accidental release event could be a pressurized powder release. Pressurized powder release experiments performed in static air measured the mass airborne and particle size distribution of these aerosols as a function of source size and containment pressure. Both containment pressure and source size were significant in pressurized powder releases. Release in static air can be estimated using the relationships developed in this work. Weight percent of the source powder airborne ranged from approximately 2 to 24%. Mass median aerodynamic equivalent diameters of the airborne particles ranged from 5 to 19 microns. All of the pressurized releases produced a significant fraction of respirable particles 10 microns AED and less. PMID:6881059

  4. Apollo experience report: Pressure vessels

    NASA Technical Reports Server (NTRS)

    Ecord, G. M.

    1972-01-01

    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.

  5. [Blood pressure self measurement (BPSM)].

    PubMed

    Eckert, Siegfried

    2006-09-14

    Blood pressure self measurement (BPSM) offers advantages over measurements in the doctor's office, and may improve the overall management of hypertension. BPSM permits the identification of "white-coat hypertension" and "masked hypertension". Longitudinal studies are needed to determine the true importance of BPSM. Doctors must be aware of the strengths and weaknesses of BPSM and be able to provide their patients with information about available devices for self measurement, in particular about the accuracy and reliability of the devices they are using. Patient training in blood pressure measurement should concentrate on classification of blood pressure, blood pressure variability, standardized self measurement, interpretation of the readings, and treatment of hypertension. PMID:17036901

  6. 42 CFR 84.157 - Airflow resistance test; Type C supplied-air respirator, pressure-demand class; minimum...

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ...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...

  7. 42 CFR 84.157 - Airflow resistance test; Type C supplied-air respirator, pressure-demand class; minimum...

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ...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...

  8. 42 CFR 84.157 - Airflow resistance test; Type C supplied-air respirator, pressure-demand class; minimum...

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...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...

  9. 42 CFR 84.157 - Airflow resistance test; Type C supplied-air respirator, pressure-demand class; minimum...

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ...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...

  10. 42 CFR 84.157 - Airflow resistance test; Type C supplied-air respirator, pressure-demand class; minimum...

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ...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...

  11. Hydraulic fracturing pressures in permeable surface layers

    Microsoft Academic Search

    Hagoort

    1978-01-01

    A theoretical analysis is presented of hydraulic fracturing pressures in permeable subsurface layers situated in a tectonically relaxed area. The analysis is based on the theory of linear poro-elasticity. Three different fracturing pressures can be distinguished: (1) fracture initiation pressure: the pressure in the borehole needed to part undamaged rock around the borehole; (2) fracture opening\\/closing pressure: the pressure in

  12. Calibration of the Photoplethysmogram to Arterial Blood Pressure: Capabilities and Limitations for Continuous Pressure Monitoring

    Microsoft Academic Search

    P. Shaltis; A. Reisner; H. Asada

    2005-01-01

    It is well known that the photoplethysniogram (PPG) is related to the underlying arterial blood pressure (ABP). However, there is ambiguity regarding the precise relationship of these two circulatory signals: some investigators have described a static relationship, while others have used more complex dynamic characterizations. This paper attempts to reconcile these models, employing results obtained from controlled human subject tests.

  13. Demodulation system for fiber optic Bragg grating dynamic pressure sensing

    Microsoft Academic Search

    John D. Lekki; Grigory Adamovsky; Bertram Floyd

    2001-01-01

    Fiber optic Bragg gratings have been used for years to measure quasi-static phenomena. In aircraft engine applications there is a need to measure dynamic signals such as variable pressures. In order to monitor these pressures a detection system with broad dynamic range is needed. This paper describes an interferometric demodulator that was developed and optimized for this particular application. The

  14. Low-Pressure Wellhead for High-Pressure Stimulation

    Microsoft Academic Search

    Tom Garvin

    1994-01-01

    Maturity of US Producing wells and constrained economics dictate careful planning and strict attention to details to optimize workover and recompletion operations. One aspect of operations that can significantly reduce costs is planned preparation of a wellheat for high-pressure stimulation. Historically, there have been four basic approaches to solving old wellhead configuration problems to prepare for high-pressure stimulation down casing.

  15. Statistics of pressure and pressure gradient in homogeneous isotropic turbulence

    NASA Technical Reports Server (NTRS)

    Gotoh, T.; Rogallo, R. S.

    1994-01-01

    The statistics of pressure and pressure gradient in stationary isotropic turbulence are measured within direct numerical simulations at low to moderate Reynolds numbers. It is found that the one-point pdf of the pressure is highly skewed and that the pdf of the pressure gradient is of stretched exponential form. The power spectrum of the pressure P(k) is found to be larger than the corresponding spectrum P(sub G)(k) computed from a Gaussian velocity field having the same energy spectrum as that of the DNS field. The ratio P(k)/P(sub G)(k), a measure of the pressure-field intermittence, grows with wavenumber and Reynolds number as -R(sub lambda)(exp 1/2)log(k/k(sub d)) for k less than k(sub d)/2 where k(sub d) is the Kolmogorov wavenumber. The Lagrangian correlations of pressure gradient and velocity are compared and the Lagrangian time scale of the pressure gradient is observed to be much shorter than that of the velocity.

  16. Pressure Dependence of Laser-Induced Dielectric Breakdown in Water

    Microsoft Academic Search

    Jonathan Robert Sukovich; Ashwinkumar Sampathkumar; R. Glynn Holt

    2011-01-01

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

  17. Automated high pressure cell for pressure jump x-ray diffraction.

    PubMed

    Brooks, Nicholas J; Gauthe, Beatrice L L E; Terrill, Nick J; Rogers, Sarah E; Templer, Richard H; Ces, Oscar; Seddon, John M

    2010-06-01

    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. PMID:20590253

  18. A dynamic pressure source for the calibration of pressure transducers

    NASA Technical Reports Server (NTRS)

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

    1976-01-01

    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.

  19. High pressure and high temperature apparatus

    DOEpatents

    Voronov, Oleg A.

    2005-09-13

    A design for high pressure/high temperature apparatus and reaction cell to achieve .about.30 GPa pressure in .about.1 cm volume and .about.100 GPa pressure in .about.1 mm volumes and 20-5000.degree. C. temperatures in a static regime. The device includes profiled anvils (28) action on a reaction cell (14, 16) containing the material (26) to be processed. The reaction cell includes a heater (18) surrounded by insulating layers and screens. Surrounding the anvils are cylindrical inserts and supporting rings (30-48) whose hardness increases towards the reaction cell. These volumes may be increased considerably if applications require it, making use of presses that have larger loading force capability, larger frames and using larger anvils.

  20. dc arc interruption in pressurized gasses

    SciTech Connect

    Chowdhuri,P.

    1980-01-01

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

  1. Automated office blood pressure.

    PubMed

    Myers, Martin G; Godwin, Marshall

    2012-05-01

    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

  2. Advanced Pressure Boundary Materials

    SciTech Connect

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

    2007-01-01

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

  3. Pressure-induced polymerization in substituted acetylenes

    SciTech Connect

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

    2012-04-10

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

  4. Pressure-induced Polymerization in Substituted Acetylenes

    NASA Astrophysics Data System (ADS)

    Chellappa, Raja; Dattelbaum, Dana; Sheffield, Stephen

    2012-02-01

    A fundamental understanding of shock-induced chemical reactions in organics is still lacking and there are limited studies devoted to determining reaction mechanisms, evolution of bonding, and effect of functional group substitutions. The fast timescale of reactions occurring during shock compression create significant experimental challenges (diagnostics) to fully quantify the mechanisms involved. Static compression provides a complementary route to investigate the equilibrium phase space and metastable intermediates during high pressure chemistry, although at a much slower timescale. In this study, we present our results from our ongoing high pressure in situ synchrotron x-ray diffraction and vibrational spectroscopy experiments on substituted acetylenes: tert-butyl acetylene [TBA: (CH3)3-C?CH] and ethynyl trimethylsilane [ETMS: (CH3)3-SiC?CH]. We observed that the onset pressure of chemical reactions (at room temperature) in these compounds is significantly higher in static compression (TBA: 11 GPa and ETMS: 26 GPa) when compared to shock input pressures (TBA: 6.1 GPa and ETMS: 6.6 GPa). The products were polymeric in nature, recovered to ambient conditions with little degradation and fully characterized using spectroscopy, calorimetry, and other techniques to identify reaction mechanisms.

  5. Pressure-induced polymerization in substituted acetylenes

    NASA Astrophysics Data System (ADS)

    Chellappa, Raja; Dattelbaum, Dana M.; Sheffield, S. A.; Robbins, David L.

    2012-03-01

    A fundamental understanding of shock-induced chemical reactions in organics is still lacking and there are limited studies devoted to determining reaction mechanisms, evolution of bonding, and effect of functional group substitutions. The fast timescale of reactions occurring during shock compression create significant experimental challenges (diagnostics) to fully quantify the mechanisms involved. Static compression combined with temperature provides a complementary route to investigate the equilibrium phase space and metastable intermediates under extreme P-T conditions. In this study, we present our results from our ongoing high pressure in situ synchrotron x-ray diffraction experiments on substituted acetylenes: tert-butyl acetylene [TBA: (CH3)3-C=CH] and ethynyl trimethylsilane [ETMS: (CH3)3-SiC=CH]. We observed that the onset pressure of chemical reactions (at room temperature) in these compounds is higher under static compression (TBA: 12 GPa and ETMS: 17.6 GPa) when compared to shock input pressures (TBA: 6.1 GPa and ETMS: 6.6 GPa). At elevated temperatures, reactivity was observed to occur at pressures comparable to shock conditions. The products were polymeric in nature, recovered to ambient conditions with little degradation.

  6. Pressure-induced Polymerization in Substituted Acetylenes

    NASA Astrophysics Data System (ADS)

    Chellappa, Raja; Dattelbaum, Dana; Sheffield, Stephen; Robbins, David

    2011-06-01

    A fundamental understanding of shock-induced chemical reactions in organics is still lacking and there are limited studies devoted to determining reaction mechanisms, evolution of bonding, and effect of functional group substitutions. The fast timescale of reactions occurring during shock compression create significant experimental challenges (diagnostics) to fully quantify the mechanisms involved. Static compression provides a complementary route to investigate the equilibrium phase space and metastable intermediates during high pressure chemistry, although at a much slower timescale. In this study, we present our results from our ongoing high pressure in situ synchrotron x-ray diffraction and vibrational spectroscopy experiments on substituted acetylenes: tert-butyl acetylene [TBA: (CH3)3 -C ?CH] and ethynyl trimethylsilane [ETMS: (CH3)3 -Si ?CH]. We observed that the onset pressure of chemical reactions (at room temperature) in these compounds is significantly higher in static compression (TBA: 11 GPa and ETMS: 26 GPa) when compared to shock input pressures (TBA: 6.1 GPa and ETMS: 6.6 GPa). The products were polymeric in nature, recovered to ambient conditions with little degradation and fully characterized using spectroscopy, calorimetry, and other techniques to identify reaction mechanisms. LDRD-DR (PI: Dana Dattelbaum)

  7. Diabetes and blood pressure (image)

    MedlinePLUS

    People with diabetes have a higher risk for heart attacks and strokes. Your doctor or nurse should check your blood pressure ... People with diabetes have a higher risk for heart attacks and strokes. Your doctor or nurse should check your blood pressure ...

  8. Pressure coring provides innovative approach

    Microsoft Academic Search

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

    1981-01-01

    Pressure coring offers the industry a new perspective in tertiary recovery project evaluation. Engineering of experimental tests requires innovative thinking and results in a higher degree of data reliability. Residual water saturation after waterflood should be the primary objective of the experimental project. The project manager should not consider the pressure core as a sole source of data. By combing

  9. Paediatric blood pressure and anaesthesia.

    PubMed

    Mather, C M

    1991-05-01

    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

  10. Pressure sensitive paint flight test

    Microsoft Academic Search

    S. W. Houck; R. G. Hepp; M. J. Morris; M. E. Benne

    1996-01-01

    Measurements based on pressure-sensitive paint were successfully demonstrated during flight test. A Mk76 practice bomb was painted with pressure sensitive paint and mounted on an A-6 attack jet. The PSP on the bomb was illuminated with a battery operated strobe and the luminescence was detected using film and a 35 mm camera. The hardware adapted to make PSP measurements for

  11. MAIN CHAMBER NEUTRAL PRESSURE IN

    E-print Network

    Pitcher, C. S.

    MAIN CHAMBER NEUTRAL PRESSURE IN ALCATOR C-MOD AND JET C S Pitcher, S K Erents*, W Fundamenski*, B on Controlled Fusion and Plasma Physics 18 ­ 22 June 1999, Madeira, Portugal MAIN CHAMBER NEUTRAL PRESSURE Science Centre, Abingdon, Oxon OX14 3DB,UK #12;(1) Introduction · main chamber gas can have a number

  12. Electrokinetically pumped high pressure sprays

    DOEpatents

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

    2005-11-01

    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.

  13. Electrokinetically pumped high pressure sprays

    DOEpatents

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

    2002-01-01

    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.

  14. Particle pressures in fluidized beds

    SciTech Connect

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

    1992-01-01

    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.

  15. Reusable High-Pressure Connector

    NASA Technical Reports Server (NTRS)

    Jensen, H. O. C.; Maltby, H. M.; Stein, J. A.

    1983-01-01

    Fluid line connector for high pressure tests has split ferrule, nut, and O-ring seal. Following test, ferrule nut, and O-ring fitting are removed leaving line unaltered except for bushing braze to free end. Connector assures strong joint for high-pressure testing without redundant parts requiring postest debrazing.

  16. Tank Pressure Control Experiment (TPCE)

    NASA Technical Reports Server (NTRS)

    Bentz, Mike

    1992-01-01

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

  17. The Pressure-Volume Curve Is Greatly Modified by Recruitment A Mathematical Model of ARDS Lungs

    Microsoft Academic Search

    KEITH G. HICKLING

    A mathematical model of the ARDS lung, with simulated gravitational superimposed pressure, evalu- ated the effect of varying alveolar threshold opening pressures (TOP), PEEP and peak inspiratory pressure (PIP) on the static pressure-volume (PV) curve. The lower inflection point (Pflex) was af- fected by SP and TOP, and did not accurately indicate PEEP required to prevent end-expiratory col- lapse. Reinflation

  18. High-pressure Raman scattering and inelastic neutron scattering studies of triaminotrinitrobenzene

    Microsoft Academic Search

    Sushil K. Satija; Basil Swanson; Juergen Eckert; J. A. Goldstone

    1991-01-01

    The authors report the results of the effect of static pressure on the Raman spectrum of TATB up to pressures of 160 kbar and deuterated TATB (DTATB) up to pressures of 65 kbar. Both these solids are found to be remarkably stable to high densities. Unusual pressure dependence of the [delta][sub NO[sub 2

  19. High-pressure Raman scattering and inelastic neutron scattering studies of triaminotrinitrobenzene

    SciTech Connect

    Satija, S.K.; Swanson, B.; Eckert, J.; Goldstone, J.A. (Los Alamos National Lab., NM (United States))

    1991-11-28

    The authors report the results of the effect of static pressure on the Raman spectrum of TATB up to pressures of 160 kbar and deuterated TATB (DTATB) up to pressures of 65 kbar. Both these solids are found to be remarkably stable to high densities. Unusual pressure dependence of the [delta][sub NO[sub 2

  20. Pressurized high frequency thermoacoustic engines

    NASA Astrophysics Data System (ADS)

    Webb, Nicholas D.

    Acoustic heat engines show much promise for converting waste heat to electricity. Since most applications require high power levels, high frequency thermoacoustic engines can reach such performance by operating with a pressurized working gas. Results on a 3 kHz prime mover, consisting of a quarter-wave resonator and a random stack material between two heat exchangers, show that the acoustic power from such a device is raised substantially as the working gas is pressurized. At pressures up to approximately 10 bar, the increase in acoustic power is approximately linear to the increase in pressure, and thus is an effective way to increase the power output of thermoacoustic engines. Since the heat input was not changed during the experiments, the increases in acoustic power translate directly to increases in engine efficiency which is calculated as the output acoustic power divided by the input heat power. In most experiments run in this study, the engine efficiency increased by a factor of at least 4 as the pressure was increased from 2 bar up to about 10 bar. Further increases in pressure lead to acoustic power saturation and eventual attenuation. This is most likely due to a combination of several factors including the shrinking thermal penetration depth, and the fact that the losses increase faster with pressure in a random stack material than in traditional parallel plates. Pressurization also leads to a lower DeltaT for onset of oscillations in the range of 10 bar of mean pressure, potentially opening up even more heat sources that can power a thermoacoustic engine. Results from another 3 kHz engine, one that was pressurized itself as opposed to being placed in a pressurized chamber, are also presented. The configuration of this engine solves the problem of how to simultaneously pressurize the engine and inject heat into the hot heat exchanger. It was also noted that the geometry of the resonator cavity in the quarter wavelength pressurized engine plays an important role in the determination of the resonance frequency of the engine, and special care needs to be taken to ensure that the stack is positioned correctly with regards to the resonance frequency. Pressurization promises to greatly increase the number of applications of acoustic engines to a variety of real world settings, providing a key source of renewable energy for the future.

  1. Fundamentals of high pressure adsorption.

    PubMed

    Zhou, Yaping; Zhou, Li

    2009-12-01

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

  2. Challenging the pressure sore paradigm.

    PubMed

    Price, P; Bale, S; Newcombe, R; Harding, K

    1999-04-01

    This study determines the effectiveness of a new low-unit-cost support system in patients at very high risk of developing pressure sores. In a prospective randomised controlled trial, a low-pressure inflatable mattress and cushion system (Repose) was compared to a dynamic support mattress (Nimbus II) used in conjunction with an alternating-pressure cushion (Alpha TranCell) in 80 patients with fractured neck of femur and high scores on a pressure sore risk assessment scale. All patients received best standard care, including turning at regular intervals. Skin condition was assessed in 17 locations on admission, preoperatively, and seven and 14 days postoperatively. No difference was found between the groups in skin condition or the occurrence and severity of pressure sores at any time point. PMID:10455633

  3. Fundamentals of high pressure adsorption

    SciTech Connect

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

    2009-12-15

    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.

  4. Electronic transmission pressure modulation valve

    SciTech Connect

    Van Elslander, E.J.

    1984-01-01

    Automatic transmissions require that the transition or shift quality between the various gears be smooth and uniform. Driveability is improved by optimizing the shift time of certain gear changes. An added benefit of improved shift quality is reduced clutch wear. During the investigation of an electronic transmission control system for agriculatural, off highway and, heavy duty on highway vehicles, it became apparent that a key element in hydraulic system was the need to accurately regulate oil pressure to the various clutches in the gear train. The valve described herein accurately regulates oil pressure at low levels and progressively increases pressure, with respect to time, by means of an electronically programmable pressure vs time control to any level up to supply pressure.

  5. Pressure rig for repetitive casting

    NASA Technical Reports Server (NTRS)

    Vasquez, Peter (inventor); Hutto, William R. (inventor); Philips, Albert R. (inventor)

    1989-01-01

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

  6. Pressurized Lunar Rover (PLR)

    NASA Astrophysics Data System (ADS)

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

    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.

  7. Pressurized Lunar Rover (PLR)

    NASA Technical Reports Server (NTRS)

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

    1992-01-01

    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.

  8. Organic electronics based pressure sensor towards intracranial pressure monitoring

    NASA Astrophysics Data System (ADS)

    Rai, Pratyush; Varadan, Vijay K.

    2010-04-01

    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.

  9. 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)

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

    1984-01-01

    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.

  10. 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)

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

    1983-01-01

    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.

  11. High-Pressure Vibrational Spectroscopy.

    NASA Astrophysics Data System (ADS)

    Pogson, Mark

    1987-09-01

    Available from UMI in association with The British Library. Requires signed TDF. The study of solids at high pressure and variable temperature enables development of accurate interatomic potential functions over wide ranges of interatomic distances. A review of the main models used in the determination of these potentials is given in Chapter one. A discussion of phonon frequency as a variable physical parameter reflecting the interatomic potential is given. A high pressure Raman study of inorganic salts of the types MSCN, (M = K,Rb,Cs & NH_4^+ ) and MNO_2, (M = K,Na) has been completed. The studies have revealed two new phases in KNO_2 and one new phase in NaNO _2 at high pressure. The accurate phonon shift data have enabled the determination of the pure and biphasic stability regions of the phases of KNO _2. A discussion of the B1, B2 relationship of univalent nitrites is also given. In the series of thiocyanates studied new phases have been found in all four materials. In both the potassium and rubidium salts two new phases have been detected, and in the ceasium salt one new phase has been detected, all at high pressure, from accurate phonon shift data. These transitions are discussed in terms of second-order mechanisms with space groups suggested for all phases, based on Landau's theory of second-order phase transitions. In the ammonium salt one new phase has been detected. This new phase transition has been interpreted as a second-order transition. The series of molecular crystals CH_3 HgX, (X = Cl,Br & I) has been studied at high pressure and at variable temperature. In Chapter five, their phase behaviour at high pressure is detailed along with the pressure dependencies of their phonon frequencies. In the chloride and the bromide two new phases have been detected. In the bromide one has been detected at high temperature and one at high pressure, and latter being interpreted as the stopping of the methyl rotation. In the chloride one phase has been found at both low temperature as well as high pressure, and the other only at high pressure, the latter again associated with the stopping of methyl rotation. The iodide displays two high pressure transitions. A Raman -active soft-mode has been observed in all three analogues, at both high pressure and variable temperature. For the chloride and bromide analogues there is a discussion of the nature of the soft-mode along with the mechanism associated with the I/II transition. The results of the X-ray crystal structure determination of CH_3HgBr at ambient temperature and pressure are given.

  12. Effects of vaned diffuser pressure recovery on centrifugal compressor stage performance 

    E-print Network

    Eason, Robyn Monique

    1985-01-01

    Diffuser, ?l 19(b) S~se Pressure Distribution at 100% N for Diffuser ?2 54 55 20(a) Static Pressure Recovery Coefficients for Diffuser ?1 20(b) Static P~ Recovery Coefficients for Diffuser ?2 57 58 21(a) Perf~ Characteristics for Diffuser ?1... ? ? ? 64 21(b) Performance Characteristics for Diffuser ?2 ? ? 65 22 Experimental Perfounance Canpariscn Between Diffusers ?1 and ?2 69 A ? flow area A/A* ? critical area ratio B ? blockage factor C ? static pressure recovery coefficient P c...

  13. Pressurized lunar rover

    NASA Technical Reports Server (NTRS)

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

    1992-01-01

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

  14. Serotonin and Blood Pressure Regulation

    PubMed Central

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

    2012-01-01

    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

  15. Optical calibration of pressure sensors for high pressures and temperatures

    SciTech Connect

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

    2005-05-01

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

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

    PubMed Central

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

    2012-01-01

    Purpose. Intraocular pressure (IOP) fluctuation has recently been identified as a risk factor for glaucoma progression. Further, decreases in intracranial pressure (ICP), with postulated increases in the translaminar pressure gradient across the lamina cribrosa, has been reported in glaucoma patients. We hypothesized that circadian fluctuations in IOP and the translaminar pressure gradient are influenced, at least in part, by central autonomic regulatory neurons within the dorsomedial and perifornical hypothalamus (DMH/PeF). This study examined whether site-directed chemical stimulation of DMH/PeF neurons evoked changes in IOP, ICP, and the translaminar pressure gradient. Methods. The GABAA receptor antagonist bicuculline methiodide (BMI) was stereotaxically microinjected into the DMH/PeF region of isoflurane-anesthetized male Sprague-Dawley rats (n = 19). The resulting peripheral cardiovascular (heart rate [HR] and mean arterial pressure [MAP]), IOP, and ICP effects were recorded and alterations in the translaminar pressure gradient calculated. Results. Chemical stimulation of DMH/PeF neurons evoked significant increases in HR (+69.3 ± 8.5 beats per minute); MAP (+22.9 ± 1.6 mm Hg); IOP (+7.1 ± 1.9 mm Hg); and ICP (+3.6 ± 0.7 mm Hg) compared with baseline values. However, the peak IOP increase was significantly delayed compared with ICP (28 vs. 4 minutes postinjection), resulting in a dramatic translaminar pressure gradient fluctuation. Conclusions. Chemical stimulation of DMH/PeF neurons evokes substantial increases in IOP, ICP, and the translaminar pressure gradient in the rat model. Given that the DMH/PeF neurons may be a key effector pathway for circadian regulation of autonomic tone by the suprachiasmatic nucleus, these findings will help elucidate novel mechanisms modulating circadian fluctuations in IOP and the translaminar pressure gradient. PMID:23033392

  17. Pressure Systems Energy Release Protection (Gas Pressurized Systems)

    NASA Technical Reports Server (NTRS)

    Brown, S. J. (editor)

    1986-01-01

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

  18. Gas Hydrate and Pore Pressure

    NASA Astrophysics Data System (ADS)

    Tinivella, Umberta; Giustiniani, Michela

    2014-05-01

    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.

  19. Electrokinetic high pressure hydraulic system

    DOEpatents

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

    2000-01-01

    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.

  20. Pressure Rig for Repetitive Casting

    NASA Technical Reports Server (NTRS)

    Vasquez, P.; Hutto, W. R.

    1986-01-01

    Equipment life increased by improved insulation. New design cuts time of preparation for casting from several days to about 1 hour. Savings due to elimination of lengthy heating and drying operations associated with preparation of ceramic mold. Quality of casting improved because moisture in cavity eliminated by use of insulating material, and more uniform pressure applied to process. Commercial blanket insulator protects components from heat, increasing life of pressure rig and enabling repeated use. Improved heat protection allows casting of brass and other alloys with higher melting temperatures in pressure rig.

  1. Micro packaged MEMS pressure sensor for intracranial pressure measurement

    NASA Astrophysics Data System (ADS)

    Xiong, Liu; Yan, Yao; Jiahao, Ma; Yanhang, Zhang; Qian, Wang; Zhaohua, Zhang; Tianling, Ren

    2015-06-01

    This paper presents a micro packaged MEMS pressure sensor for intracranial pressure measurement which belongs to BioMEMS. It can be used in lumbar puncture surgery to measure intracranial pressure. Miniaturization is key for lumbar puncture surgery because the sensor must be small enough to allow it be placed in the reagent chamber of the lumbar puncture needle. The size of the sensor is decided by the size of the sensor chip and package. Our sensor chip is based on silicon piezoresistive effect and the size is 400 × 400 ?m2. It is much smaller than the reported polymer intracranial pressure sensors such as liquid crystal polymer sensors. In terms of package, the traditional dual in-line package obviously could not match the size need, the minimal size of recently reported MEMS-based intracranial pressure sensors after packaging is 10 × 10 mm2. In this work, we are the first to introduce a quad flat no-lead package as the package form of piezoresistive intracranial pressure sensors, the whole size of the sensor is minimized to only 3 × 3 mm2. Considering the liquid measurement environment, the sensor is gummed and waterproof performance is tested; the sensitivity of the sensor is 0.9 × 10?2 mV/kPa. Project supported by the National Natural Science Foundation of China (Nos. 61025021, 61434001), and the ‘Thousands Talents’ Program for Pioneer Researchers and Its Innovation Team, China.

  2. Burst failure load of composite pressure vessels

    Microsoft Academic Search

    Aziz Onder; Onur Sayman; Tolga Dogan; Necmettin Tarakcioglu

    2009-01-01

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

  3. Pressure-Viscosity Coefficients of Liquid Lubricants

    Microsoft Academic Search

    Lowrie B. Sargent Jr

    1983-01-01

    The Barus equation relating viscosity to pressure includes a pressure-viscosity coefficient used widely by investigators even though that coefficient is grossly inaccurate at elevated pressures. A new empirical equation was developed relating viscosity to pressure. The equation is mathematically simple and provides two coefficients that are satisfactory over a wide pressure range. These coefficients are temperature dependent and produce a

  4. Pressure ulcer good practice published.

    PubMed

    2015-06-17

    Patients admitted to hospital or a nursing home should have a pressure ulcer risk assessment within six hours of admission, the National Institute for Health and Care Excellence has said. PMID:26080953

  5. Taking Care of Pressure Sores

    MedlinePLUS

    ... way, you will rebuild your skin pressure tolerance. University of Washington-operated SCI Clinics: Harborview Medical Center ... Spinal Cord Injury Clinic nurses: 206-744-5862. University of Washington Medical Center Rehabilitation Medicine Clinic 1959 ...

  6. Inertia of dynamic pressure arrays

    NASA Technical Reports Server (NTRS)

    Weidemann, Hans

    1941-01-01

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

  7. What Causes High Blood Pressure?

    MedlinePLUS

    ... pressure - a hypertension Google+ hangout in honor of World Hypertension Day 04/18/2013 Moderated by American ... live on April 5, 2013 in honor of World Health Day on Sunday, April 7. The NHLBI " ...

  8. Living with High Blood Pressure

    MedlinePLUS

    ... pressure - a hypertension Google+ hangout in honor of World Hypertension Day 04/18/2013 Moderated by American ... live on April 5, 2013 in honor of World Health Day on Sunday, April 7. The NHLBI " ...

  9. Managed Pressure Drilling Candidate Selection 

    E-print Network

    Nauduri, Anantha S.

    2010-07-14

    Managed Pressure Drilling now at the pinnacle of the 'Oil Well Drilling' evolution tree, has itself been coined in 2003. It is an umbrella term for a few new drilling techniques and some preexisting drilling techniques, ...

  10. Improved gas-pressure transducer

    NASA Technical Reports Server (NTRS)

    Dimeff, J.

    1977-01-01

    Optically-selective, acoustically-resonant, gas-detecting device is used to measure intensity of radiation-induced pressure variations. Use of diaphragm improves sensitivity and immunity to background noise.

  11. Self-Calibrating Pressure Transducer

    NASA Technical Reports Server (NTRS)

    Lueck, Dale E. (Inventor)

    2006-01-01

    A self-calibrating pressure transducer is disclosed. The device uses an embedded zirconia membrane which pumps a determined quantity of oxygen into the device. The associated pressure can be determined, and thus, the transducer pressure readings can be calibrated. The zirconia membrane obtains oxygen .from the surrounding environment when possible. Otherwise, an oxygen reservoir or other source is utilized. In another embodiment, a reversible fuel cell assembly is used to pump oxygen and hydrogen into the system. Since a known amount of gas is pumped across the cell, the pressure produced can be determined, and thus, the device can be calibrated. An isolation valve system is used to allow the device to be calibrated in situ. Calibration is optionally automated so that calibration can be continuously monitored. The device is preferably a fully integrated MEMS device. Since the device can be calibrated without removing it from the process, reductions in costs and down time are realized.

  12. Myths about High Blood Pressure

    MedlinePLUS

    ... can increase blood pressure dramatically. It can also cause heart failure, lead to stroke and produce irregular heartbeats. Too much alcohol can contribute to high triglycerides, cancer, obesity, alcoholism, suicide and accidents, and it can be ...

  13. Managed Pressure Drilling Candidate Selection

    E-print Network

    Nauduri, Anantha S.

    2010-07-14

    drilling hydraulics calculations and simulations. Most of them are designed for conventional well hydraulics, while some can perform Underbalanced Drilling calculations, and a select few can perform Managed Pressure Drilling calculations. Most of the few...

  14. Electrokinetic high pressure hydraulic system

    DOEpatents

    Paul, Phillip H.; Rakestraw, David J.; Arnold, Don W.; Hencken, Kenneth R.; Schoeniger, Joseph S.; Neyer, David W.

    2003-06-03

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

  15. Electrokinetic high pressure hydraulic system

    DOEpatents

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

    2001-01-01

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

  16. Pressure-actuated joint system

    NASA Technical Reports Server (NTRS)

    McGuire, John R. (Inventor)

    2004-01-01

    A pressure vessel is provided that includes first and second case segments mated with one another. First and second annular rubber layers are disposed inboard of the first and second case segments, respectively. The second annular rubber layer has a slot extending from the radial inner surface across a portion of its thickness to define a main body portion and a flexible portion. The flexible portion has an interfacing surface portion abutting against an interfacing surface portion of the first annular rubber layer to follow movement of the first annular rubber layer during operation of the pressure vessel. The slot receives pressurized gas and establishes a pressure-actuated joint between the interfacing surface portions. At least one of the interfacing surface portions has a plurality of enclosed and sealed recesses formed therein.

  17. Effects of water vapour pressure deficit and stomatal conductance on photosynthesis, internal pressurization and convective flow in three emergent wetland plants

    Microsoft Academic Search

    B. K. Sorrell; H. Brix

    2003-01-01

    Internal pressurization and convective gas flow in emergent wetland plants is a function of the water vapour pressure deficit (WPD) and stomatal conductance (Gs) separating the external atmosphere from the internal aerenchyma. We have compared the effects of WPD and Gs under a range of light intensities on static pressures and convective flows in Phragmites australis, Typha orientalis and Baumea

  18. Electrochemical studies at high pressure

    SciTech Connect

    Cruanes, M.T.

    1993-01-01

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

  19. Indirect Blood Pressure Measuring Device

    NASA Technical Reports Server (NTRS)

    Hum, L.; Cole, C. E.

    1973-01-01

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

  20. An atmospheric pressure plasma source

    Microsoft Academic Search

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

    2000-01-01

    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

  1. Pressure Modulator Radiometer (PMR) tests

    NASA Technical Reports Server (NTRS)

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

    1979-01-01

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

  2. Membrane Bioreactor With Pressure Cycle

    NASA Technical Reports Server (NTRS)

    Efthymiou, George S.; Shuler, Michael L.

    1991-01-01

    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.

  3. Measuring the pressure in ultrahigh-pressure mercury arcs

    SciTech Connect

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

    2009-09-01

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

  4. SUBNANOWATT MICROBUBBLE PRESSURE TRANSDUCER C. A. Gutierrez*

    E-print Network

    Meng, Ellis

    conventional diaphragm-based pressure transduction, enabling significant reductions in overall footprint are the pressure in the gas at the bubble wall and ambient pressure far away from the bubble (infinite distance

  5. Automatic blood pressure measuring system (M092)

    NASA Technical Reports Server (NTRS)

    Nolte, R. W.

    1977-01-01

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

  6. Constraints on Early Mars atmospheric pressure

    E-print Network

    Kite, Edwin

    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

  7. Spray bottle apparatus with pressure multiplying pistons

    DOEpatents

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

    1990-01-01

    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.

  8. Application of adaptive fuzzy control technology to pressure control of a pressurizer

    Microsoft Academic Search

    Ben-Kun Yang; Xin-Qian Bian; Wei-Lai Guo

    2005-01-01

    A pressurizer is one of important equipment in a pressurized water reactor plant. It is used to maintain the pressure of primary\\u000a coolant within allowed range because the sharp change of coolant pressure affects the security of reactor, therefor, the study\\u000a of pressurizer’s pressure control methods is very important. In this paper, an adaptive fuzzy controller is presented for\\u000a pressure

  9. High-pressure properties inferred from normal-pressure properties

    NASA Astrophysics Data System (ADS)

    Tamarit, J. Ll; Barrio, M.; Pardo, L. C.; Negrier, P.; Mondieig, D.

    2008-06-01

    From the stable and metastable normal-pressure phase equilibria involved in two-component systems sharing compounds of the series CCl4-nBrn, n = 0,...,4, several thermodynamic properties concerning non-experimentally available phase transitions have been determined. To do so, the well-established concept of crossed isodimorphism has been considered to involve the isomorphism relationships between the low-temperature monoclinic phases as well as, for both rhombohedral and face-centred cubic, orientationally disordered phases appearing in the compounds of the series. On the basis of such relations, the thermodynamic properties of the two-phase equilibria are extrapolated as a function of mole fraction to the pure compounds for which the involved transitions do not exist at normal pressure. The obtained thermodynamic properties are used to build up the topological pressure temperature phase diagrams of the compounds of the series. The results are compared with the experimental pressure temperature phase diagrams obtained by means of density measurements as a function of pressure and temperature.

  10. Optical pressure/density measuring means

    DOEpatents

    Veligdan, James T. (Manorville, NY)

    1995-05-09

    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.

  11. 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 whole body. #12; When your heart pumps, your blood pressure goes up. The pressure in your arteries is your blood pressure. · This is like pumping air into a tire. · When you push down on the pump it pumps

  12. Measuring Intracranial Pressure And Volume Noninvasively

    NASA Technical Reports Server (NTRS)

    Cantrell, John H.; Yost, William T.

    1994-01-01

    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.

  13. Transformational acoustic metamaterials based on pressure gradients

    E-print Network

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

    2014-09-18

    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.

  14. Blade Tip Pressure Measurements Using Pressure Sensitive Paint

    NASA Technical Reports Server (NTRS)

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

    2012-01-01

    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.

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

    SciTech Connect

    Foltz, M.F.

    1993-04-01

    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.

  16. A microwave pressure sounder. [for remote measurement of atmospheric pressure

    NASA Technical Reports Server (NTRS)

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

    1981-01-01

    A technique for the remote measurement of atmospheric surface pressure will be described. Such measurements could be made from a satellite in polar orbit and would cover many areas for which conventional meteorological data are not available. An active microwave instrument is used to measure the strength of return echoes from the ocean surface at a number of frequencies near the 60 GHz oxygen absorption band. Factors which affect the accuracy with which surface pressure can be deduced from these measurements will be discussed and an instrument designed to test the method by making measurements from an aircraft will be described.

  17. No correlation between intraocular pressure and intracranial pressure.

    PubMed

    Han, Ying; McCulley, Timothy J; Horton, Jonathan C

    2008-08-01

    A recent study has reported an excellent correlation between intraocular pressure (IOP) and intracranial pressure (ICP), suggesting that measurement of IOP may serve as a noninvasive means to determine ICP. To reexamine the relation between IOP and ICP, we reviewed the medical records of all patients who underwent lumbar puncture between 1991 and 2007 in the neuro-ophthalmology clinic at the University of California San Francisco. Data for IOP and ICP were available for 55 patients. There was no correlation between IOP and ICP (Pearson correlation coefficient, r = 0.07; p = 0.59). IOP measurement is not a useful substitute for ICP measurement. PMID:18570302

  18. High pressure neon arc lamp

    DOEpatents

    Sze, Robert C.; Bigio, Irving J.

    2003-07-15

    A high pressure neon arc lamp and method of using the same for photodynamic therapies is provided. The high pressure neon arc lamp includes a housing that encloses a quantity of neon gas pressurized to about 500 Torr to about 22,000 Torr. At each end of the housing the lamp is connected by electrodes and wires to a pulse generator. The pulse generator generates an initial pulse voltage to breakdown the impedance of the neon gas. Then the pulse generator delivers a current through the neon gas to create an electrical arc that emits light having wavelengths from about 620 nanometers to about 645 nanometers. A method for activating a photosensitizer is provided. Initially, a photosensitizer is administered to a patient and allowed time to be absorbed into target cells. Then the high pressure neon arc lamp is used to illuminate the target cells with red light having wavelengths from about 620 nanometers to about 645 nanometers. The red light activates the photosensitizers to start a chain reaction that may involve oxygen free radicals to destroy the target cells. In this manner, a high pressure neon arc lamp that is inexpensive and efficiently generates red light useful in photodynamic therapy is provided.

  19. Zirconate pyrochlores under high pressure

    SciTech Connect

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

    2010-07-12

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

  20. Level indicator for pressure vessels

    DOEpatents

    Not Available

    1982-04-28

    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.

  1. IIH with normal CSF pressures?

    PubMed Central

    Suh, Soh Youn; Kim, Seong-Joon

    2013-01-01

    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

  2. Downhole pump with pressure limiter

    SciTech Connect

    Brandell, J.T.

    1982-02-02

    A well testing assembly includes a pressure limiter located between a down-hole pump and an inflatable packer. The pressure limiter includes a housing having first and second housing parts and having an inflation passage disposed therein for communicating a discharge of the down-hole pump with the inflatable packer. A clutch is connected between the first and second housing parts. A biasing spring biases the clutch toward an engaged position. A piston spring biases the clutch toward an engaged position. A piston is associated operatively with the clutch and communicated with the inflation passage for overcoming the biasing spring and moving the clutch to a disengaged position at a predetermined fluid pressure level within the inflation passage. 50 claims.

  3. Pressurized-fluid-operated engine

    SciTech Connect

    Holleyman, J.E.

    1990-01-30

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

  4. Optical pressure sealing coupling apparatus

    NASA Technical Reports Server (NTRS)

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

    1989-01-01

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

  5. Accuracy of Pressure Sensitive Paint

    NASA Technical Reports Server (NTRS)

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

    2001-01-01

    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.

  6. Melting of Ice under Pressure

    SciTech Connect

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

    2008-07-31

    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.

  7. Wall Pressure Spectral Model Including the Adverse Pressure Gradient Effects

    E-print Network

    Paris-Sud XI, Université de

    of the boundary layer parameters characterizing the pressure gradient effects is provided and the more relevant by means of an aeroacoustic analogy, namely Amiet's theory of turbulent boundary layer past a trailing edge. The results are compared to experimental data obtained in open-jet anechoic wind tunnel. 1 Research Engineer

  8. Partial pressure analysis of plasmas

    SciTech Connect

    Dylla, H.F.

    1984-11-01

    The application of partial pressure analysis for plasma diagnostic measurements is reviewed. A comparison is made between the techniques of plasma flux analysis and partial pressure analysis for mass spectrometry of plasmas. Emphasis is given to the application of quadrupole mass spectrometers (QMS). The interface problems associated with the coupling of a QMS to a plasma device are discussed including: differential-pumping requirements, electromagnetic interferences from the plasma environment, the detection of surface-active species, ion source interactions, and calibration procedures. Example measurements are presented from process monitoring of glow discharge plasmas which are useful for cleaning and conditioning vacuum vessels.

  9. Measuring Blood Pressure in Space

    NSDL National Science Digital Library

    Marlene Y. MacLeish

    2012-06-26

    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.

  10. Pressure relief subsystem design description

    SciTech Connect

    NONE

    1986-07-01

    The primary function of the Pressure Relief Subsystem, a subsystem of the Vessel System, is to provide overpressure protection to the Vessel System. When the overpressure setpoint is reached, pressure is reduced by permitting the flow of primary coolant out of the Vessel System. This subsystem also provides the flow path by which purified helium is returned to the vessel system, either as circulating purge/flow from the Helium Purification Subsystem or make-up helium from the Helium Storage and Transfer Subsystem.

  11. Characterization of pressure transducers for future cryogenic wind tunnels

    NASA Astrophysics Data System (ADS)

    Portat, M.; Helias, F.

    1984-04-01

    Operating cryogenic wind tunnels will require measurement equipment adapted to the specific environmental conditions. Among other things, it must be known how the existing wind tunnel pressure transducers will behave in a cryogenic environment. To this end, ONERA has developed special instruments to measure pressure transducer characteristics accurately between 300 and 120 K. Static tests carried out on the Kulite XCQL and ONERA 20H130 transducers show that they are usable at 120 K.

  12. Blood pressure reprogramming adapter assists signal recording

    NASA Technical Reports Server (NTRS)

    Vick, H. A.

    1967-01-01

    Blood pressure reprogramming adapter separates the two components of a blood pressure signal, a dc pressure signal and an ac Korotkoff sounds signal, so that the Korotkoff sounds are recorded on one channel as received while the dc pressure signal is converted to FM and recorded on a second channel.

  13. ORIGINAL ARTICLE Usefulness of ambulatory blood pressure

    E-print Network

    Cai, Long

    ORIGINAL ARTICLE Usefulness of ambulatory blood pressure monitoring in predicting the presence whether nondipping (defined as a day­night change in blood pressure (BP) p0%) could be assumed pressure monitoring; diagnosis Introduction Ambulatory blood pressure (BP) monitoring (ABPM) has been

  14. A piezo-bar pressure probe

    NASA Technical Reports Server (NTRS)

    Friend, W. H.; Murphy, C. L.; Shanfield, I.

    1967-01-01

    Piezo-bar pressure type probe measures the impact velocity or pressure of a moving debris cloud. It measures pressures up to 200,000 psi and peak pressures may be recorded with a total pulse duration between 5 and 65 musec.

  15. High pressure processing for food safety

    Microsoft Academic Search

    M. Fonberg-Broczek; B. Windyga; Jacek Szczawi?ski; M. Szczawi?ska; D. Pietrzak; G. Prestamo

    Food preservation using high pressure is a promising technique in food industry as it offers nu- merous opportunities for developing new foods with extended shelf-life, high nutritional value and excellent organoleptic characteristics. High pressure is an alternative to thermal processing. The resistance of microorganisms to pressure varies considerably depending on the pressure range applied, temperature and treatment duration, and type

  16. Determination of Secondary Encasement Pipe Design Pressure

    SciTech Connect

    TEDESCHI, A.R.

    2000-10-26

    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.

  17. Application of centrifugal compressors to pressure decline

    Microsoft Academic Search

    Hammel; A. J. Jr

    1973-01-01

    A partial map is shown of the U.S. pressure decline fields. These include the San Juan pressure decline, the Lea County pressure decline, and Delaware Basin pressure decline. The depletion of gas reserves now being talked about so frequently actually starts as soon as gas is removed from a reservoir. The usual means of coping with the depletion of gas

  18. Personal Cabin Pressure Monitor and Warning System

    Microsoft Academic Search

    Jan A. Zysko

    2002-01-01

    A cabin pressure altitude monitor and warning system provides a warning when a detected cabin pressure altitude has reached a predetermined level. The system is preferably embodied in a portable, pager-sized device that can be carried or worn by an individual. A microprocessor calculates the pressure altitude from signals generated by a calibrated pressure transducer and a temperature sensor that

  19. Hydraulic transients cause low-pressure problems

    Microsoft Academic Search

    Thomas M. Walski; Teresa L. Lutes

    1994-01-01

    Most engineers are familiar with hydraulic transients that cause problems with excessive pressure in water distribution systems. However, transients can also cause short-lived low-pressure problems. This article describes the analysis conducted by the Austin (Texas) Water and Wastewater Utility that identified transients as the source of low pressures in a portion of the city. Pressures recorded during controlled conditions provided

  20. Pressure transducer with multiplexed frequency transmitter

    Microsoft Academic Search

    R. Vrba; M. Sveda; K. Marecek

    2004-01-01

    The pressure transducer for precise and reliable pressure measurement is described. Its aim was to reach better pressure ranges with lower price. The ceramic diaphragm for pressure sensing is applied and a new principle of special ASIC with multiplexed frequency transmitter for conditioning of fX and fR frequencies controlled by CX and CR sensor capacitances is exploit. Good protection against

  1. Vapor Pressure Measurements in a Closed System

    ERIC Educational Resources Information Center

    Iannone, Mark

    2006-01-01

    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…

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

    Microsoft Academic Search

    M. Ruzzene; A. Baz

    2006-01-01

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

  3. Calculation of pressure waves in substation buildings due to arcing faults

    Microsoft Academic Search

    A. Dasbach; G. J. Pietsch

    1990-01-01

    Pressure stress from internal arcing includes static and dynamic phenomena. These phenomena can be distinguished with the help of the pulsation factor. The ray tracing technique presented allows the three-dimensional calculation of pressure stresses including transient effects. Two examples demonstrating the importance of pressure waves on the stress of rooms are presented. A calculation procedure is given which enables an

  4. Orion Suit Loop Variable Pressure Regulator Development

    NASA Technical Reports Server (NTRS)

    Mosher, Michael; Lewis, John F.; Campbell, Melissa

    2012-01-01

    The Orion Multi Purpose Crew Vehicle (MPCV) integrates the cabin and pressure suits with the core life support systems to provide life support during contingency depressurized cabin operations. To provide the multiple suit pressures between nominal pressurized cabin suited operations, suit leak checks, depressurized cabin suited operations, and elevated suit pressure for denitrification, a variable pressure regulator is needed. This paper documents the development of the suit loop regulator for Orion.

  5. Orion Suit Loop Variable Pressure Regulator Development

    NASA Technical Reports Server (NTRS)

    Mosher, Michael; Vassallo, Andrew; Lewis, John F.; Campbell, Melissa

    2014-01-01

    The Orion Multi Purpose Crew Vehicle (MPCV) integrates the cabin and pressure suits with the core life support systems to provide life support during contingency depressurized cabin operations. To provide the multipule suit pressures between nominal pressurized cabin suited operations, suit leak checks, depressurized cabin suited operations, and elevated suit pressure for denitrification, a variable pressure regulator is needed. This paper documents the development and integrated testing of the suit loop regulator for Orion.

  6. Pressure-Sensitive Resistor Material

    NASA Technical Reports Server (NTRS)

    Du Fresne, E. R.

    1986-01-01

    Low-conductivity particles in rubber offer wide dynamic range. Sensor consists of particles of relatively low conductivity embedded in rubber. Resistance of sensor decreases by about 100 times as pressure on it increases from zero to 0.8 MN/M to the second power. Resistor promising candidate as tactile sensor for robots and remote manipulators.

  7. Research study of pressure instrumentation

    NASA Technical Reports Server (NTRS)

    Hoogenboom, L.; Hull-Allen, G.

    1984-01-01

    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.

  8. Low pressure plasma spray coatings

    Microsoft Academic Search

    Elizabeth J Young; Eli Mateeva; John J Moore; Brajendra Mishra; Michael Loch

    2000-01-01

    A new technique — low-pressure plasma spray (LPPS) — has been used for deposition of high quality Al2O3 coatings on aluminum substrates for many different applications. The initial results on the properties and structure of the LPPS alumina coating are presented in this paper. Chemical compositional analysis using secondary neutral mass spectroscopy (SNMS) has shown that the coatings are close

  9. High pressure well perforation cleaning

    SciTech Connect

    Buell, R.S.

    1991-10-29

    This patent describes an apparatus for jet washing perforation tunnels in a well casing or liner positioned in a well and perforation tunnels in an adjacent geologic formation. It comprises a tubing means forming a well flow path from the earth's surface to a location adjacent to the well liner positioned in the well; conduit means connecting a source of high pressure liquid to the tubing means, jet tool means having at least one hole in the wall thereof for jetting the high pressure liquid at the perforation tunnels in the well casing or liner, the jet tool means comprising a tubular member connected to the lower end of the tubing means; a jet seat member fixedly connected to the tubular member, the jet seat member having a central opening aligned with the hole and a jet body having a central opening at least 3/23 inch in diameter formed therein hydraulically sealed in the jet seat member, whereby the jet body may be rotated to provide axial movement of the jet body with respect to the jet seat member; and a source of high pressure liquid able to provide a hydraulic horsepower for supplying liquid at a flow rate of at least 0.77 barrels per minute per jet body used at pressures in excess of 5,000 psi, to wash the perforated tunnel to a standoff distance of at least 12 times the diameter of the central opening of the jet body.

  10. Mass gap from pressure inequalities

    E-print Network

    Tamas S. Biro; Andras Laszlo; Peter Van

    2006-12-07

    We prove that a temperature independent mass distribution is identically zero below a mass threshold (mass gap) value, if the pressure satisfies certain inequalities. This supports the finding of a minimal mass in quark matter equation of state by numerical estimates and by substitution of analytic formulas. We present a few inequalities for the mass distribution based on the Markov inequality.

  11. SOL Tests Create Unfair Pressure.

    ERIC Educational Resources Information Center

    Ernst, Katie

    2000-01-01

    A seventh-grader explains why the Virginia Standards of Learning tests unfairly pressure her and her teachers. She wants her free reading time restored and wishes politicians would worry more about students understanding--not just memorizing--facts. She praises teachers who go beyond the SOL. (MLH)

  12. RBMK pressure tube rupture assessment

    Microsoft Academic Search

    B. E. Schmitt; G. V. Tsiklauri

    1994-01-01

    The Russian RBMK reactor core design consists of multiple parallel pressure tube channels that contain Zr clad, UOâ 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

  13. Stirling engine with pressurized crankcase

    DOEpatents

    Corey, John A. (Melrose, NY)

    1988-01-01

    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.

  14. ORIGINAL ARTICLE Blood pressure, antihypertensive

    E-print Network

    Cai, Long

    pressure control in hypertensive diabetics: the Tarmidas study P de Pablos-Velasco1 , O Gonzalez-Albarran2 studies confirm the high preva- lence of hypertension in type II diabetic (DM2) subjects and that intensive antihypertensive treatment is more beneficial to diabetic than to nondiabetic hypertensive

  15. An Exercise in Air Pressure

    NSDL National Science Digital Library

    Carrie Talus

    2003-01-01

    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.

  16. Testosterone and Blood Pressure Regulation

    Microsoft Academic Search

    Tina Kienitz; Marcus Quinkler

    2008-01-01

    Background: There is substantial evidence that androgens may play a role in determining sex-specific blood pressure. Men are at higher risk for developing coronary heart disease or hypertension compared to premenopausal women. However, effects of androgens on the renal and cardiovascular system are complex. This review provides a critical overview of testosterone actions. Methods: We searched Pubmed library for experimental,

  17. Student Pressure Subject of Debate

    ERIC Educational Resources Information Center

    Gewertz, Catherine

    2006-01-01

    This article discusses student pressure as a subject of debate. The latest debate about schoolwork is being fueled by three recent books: "The Homework Myth" by Alfie Kohn, "The Case Against Homework" by Sara Bennett and Nancy Kalish, and "The Overachievers", by Alexandra Robbins, which depicts overextended high school students in a wealthy…

  18. "Can" You Stand the Pressure

    NSDL National Science Digital Library

    2012-06-26

    In this activity about states of matter, learners get to witness firsthand the awesome power of air pressure. They watch as an ordinary soda can is crushed by invisible forces. This activity is only to be done with adult supervision, as it involves very hot water.

  19. Pressure vessel having continuous sidewall

    NASA Technical Reports Server (NTRS)

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

    2011-01-01

    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.

  20. Pitfalls in pressure guage performance

    SciTech Connect

    Kikani, J.; Fair, P.S.; Hite, R.H. [SPE, Richardson, TX (United States)

    1995-12-31

    Often, pressure gauge systems for surface read-out (SRO) wireline work or for permanent installations do not perform according to their specifications i.e. the pressure resolution obtained is lower than the gauge design values. This seems natural because the borehole environment is nastier than the quiescence of laboratory calibration setup. Nevertheless, it is difficult to attribute the loss of resolution to a single problem. This paper introduces the functional components of the pressure gauge system where loss of resolution may occur. Specifically, cable related problems, crossover, signal transmission, signal processing, time stamping and temperature compensation are addressed. Determination of pressure resolution from a processed signal is shown via example calculations. The role of transducer specifications on overall data quality is addressed. In other words, what causes a 0.01 psi rated transducer to yield a signal of only 0.75 psi quality? Field data from prospects Tahoe and Bullwinkle are used to illustrate some of the gauge related problems and the solutions being proposed by the industry to overcome some of them.