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Sample records for pressure static pressure

  1. Water cooled static pressure probe

    NASA Technical Reports Server (NTRS)

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

    1991-01-01

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

  2. 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.

  3. Static pressure seal of earmolds.

    PubMed

    Macrae, J

    1990-01-01

    Four experiments were carried out to investigate the effect on the static pressure seal of earmolds made from currently used impression and earmold materials; the occasional practice of making more than one earmold from an impression; the earmoldmaker buildup of impressions; and the multistage buildup of impressions by the impression taker. Experiment 1 showed that the chance of sealing the ear with earmolds made by the ordinary two-stage technique with only general buildup of the impression was approximately 10 percent and that none of the impression or earmold materials significantly improved the chance of obtaining a seal. Experiment 2 showed that the chance of obtaining a seal with multiple earmolds made from the one impression was zero, or very close to zero. Experiment 3 revealed that the chance of obtaining a seal increased to 55 percent when the earmold was made from an impression which was specially built up by the earmoldmaker. Experiment 4 showed that the chance of sealing the ear with earmolds made from multistage impressions was significantly greater (87.5 percent) than sealing the ear with those made from impressions specially built up by the earmoldmaker.

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

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 1 2012-01-01 2012-01-01 false Static pressure and pressure altimeter...: Installation § 29.1325 Static pressure and pressure altimeter systems. (a) Each instrument with static air case.... (c) Each static pressure port must be designed and located in such manner that the...

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

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 1 2013-01-01 2013-01-01 false Static pressure and pressure altimeter...: Installation § 29.1325 Static pressure and pressure altimeter systems. (a) Each instrument with static air case.... (c) Each static pressure port must be designed and located in such manner that the...

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

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Static pressure and pressure altimeter...: Installation § 29.1325 Static pressure and pressure altimeter systems. (a) Each instrument with static air case.... (c) Each static pressure port must be designed and located in such manner that the...

  7. 14 CFR 29.1325 - Static pressure and pressure altimeter systems.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Static pressure and pressure altimeter...: Installation § 29.1325 Static pressure and pressure altimeter systems. (a) Each instrument with static air case.... (c) Each static pressure port must be designed and located in such manner that the...

  8. 14 CFR 29.1325 - Static pressure and pressure altimeter systems.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Static pressure and pressure altimeter...: Installation § 29.1325 Static pressure and pressure altimeter systems. (a) Each instrument with static air case.... (c) Each static pressure port must be designed and located in such manner that the...

  9. 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.

  10. 30 CFR 18.67 - Static-pressure tests.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Static-pressure tests. 18.67 Section 18.67....67 Static-pressure tests. Static-pressure tests shall be conducted by the applicant on each enclosure... pressure to be applied shall be 150 pounds per square inch (gage) or one and one-half times the...

  11. 30 CFR 18.67 - Static-pressure tests.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 30 Mineral Resources 1 2013-07-01 2013-07-01 false Static-pressure tests. 18.67 Section 18.67....67 Static-pressure tests. Static-pressure tests shall be conducted by the applicant on each enclosure... pressure to be applied shall be 150 pounds per square inch (gage) or one and one-half times the...

  12. 30 CFR 18.67 - Static-pressure tests.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Static-pressure tests. 18.67 Section 18.67....67 Static-pressure tests. Static-pressure tests shall be conducted by the applicant on each enclosure... pressure to be applied shall be 150 pounds per square inch (gage) or one and one-half times the...

  13. 30 CFR 18.67 - Static-pressure tests.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Static-pressure tests. 18.67 Section 18.67....67 Static-pressure tests. Static-pressure tests shall be conducted by the applicant on each enclosure... pressure to be applied shall be 150 pounds per square inch (gage) or one and one-half times the...

  14. 30 CFR 18.67 - Static-pressure tests.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 30 Mineral Resources 1 2012-07-01 2012-07-01 false Static-pressure tests. 18.67 Section 18.67....67 Static-pressure tests. Static-pressure tests shall be conducted by the applicant on each enclosure... pressure to be applied shall be 150 pounds per square inch (gage) or one and one-half times the...

  15. Static spherically symmetric wormholes with isotropic pressure

    NASA Astrophysics Data System (ADS)

    Cataldo, Mauricio; Liempi, Luis; Rodríguez, Pablo

    2016-06-01

    In this paper we study static spherically symmetric wormhole solutions sustained by matter sources with isotropic pressure. We show that such spherical wormholes do not exist in the framework of zero-tidal-force wormholes. On the other hand, it is shown that for the often used power-law shape function there are no spherically symmetric traversable wormholes sustained by sources with a linear equation of state p = ωρ for the isotropic pressure, independently of the form of the redshift function ϕ (r). We consider a solution obtained by Tolman at 1939 for describing static spheres of isotropic fluids, and show that it also may describe wormhole spacetimes with a power-law redshift function, which leads to a polynomial shape function, generalizing a power-law shape function, and inducing a solid angle deficit.

  16. Thermal Transport at Static High-Pressures

    NASA Astrophysics Data System (ADS)

    Pangilinan, G. I.; Ladouceur, H. D.; Russell, T. P.

    2000-03-01

    Static properties and dynamic processes at high pressures and high temperatures are critically dependent on thermal properties of materials. Measurements of thermal properties at high pressures have only slowly developed through the years. Here we present a novel method, utilizing gem anvil cells, to measure specific heat, thermal conductivity and thermal diffusivity. The method involves launching a thermal wave in a sample. Subsequently, a localized sensor measures the temporal behavior of the temperature at a fixed point downstream in the material. A pulsed laser is used to deliver the heating pulse, while time-resolved fluorescence from a ruby sphere is used to measure the temperature. The thermal properties are inferred from the temporal behavior of the temperature and the heat conduction equations with appropriate boundary conditions. The thermal properties of table salt (NaCl) are obtained using this method. Impact to current and future high-pressure research, including materials science and geophysics will be addressed.

  17. 14 CFR 27.1325 - Static pressure systems.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 1 2012-01-01 2012-01-01 false Static pressure systems. 27.1325 Section 27... pressure systems. (a) Each instrument with static air case connections must be vented so that the influence... foreign matter does not seriously affect its accuracy. (b) Each static pressure port must be designed...

  18. 14 CFR 27.1325 - Static pressure systems.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Static pressure systems. 27.1325 Section 27... pressure systems. (a) Each instrument with static air case connections must be vented so that the influence... foreign matter does not seriously affect its accuracy. (b) Each static pressure port must be designed...

  19. 14 CFR 27.1325 - Static pressure systems.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Static pressure systems. 27.1325 Section 27... pressure systems. (a) Each instrument with static air case connections must be vented so that the influence... foreign matter does not seriously affect its accuracy. (b) Each static pressure port must be designed...

  20. 14 CFR 27.1325 - Static pressure systems.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 1 2013-01-01 2013-01-01 false Static pressure systems. 27.1325 Section 27... pressure systems. (a) Each instrument with static air case connections must be vented so that the influence... foreign matter does not seriously affect its accuracy. (b) Each static pressure port must be designed...

  1. 30 CFR 7.307 - Static pressure test.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 30 Mineral Resources 1 2012-07-01 2012-07-01 false Static pressure test. 7.307 Section 7.307... pressure test. (a) Test procedure. (1) The enclosure shall be internally pressurized to a minimum of 150 psig and the pressure maintained for a minimum of 10 seconds. (2) Following the pressure hold,...

  2. 30 CFR 7.307 - Static pressure test.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 30 Mineral Resources 1 2013-07-01 2013-07-01 false Static pressure test. 7.307 Section 7.307... pressure test. (a) Test procedure. (1) The enclosure shall be internally pressurized to a minimum of 150 psig and the pressure maintained for a minimum of 10 seconds. (2) Following the pressure hold,...

  3. 30 CFR 7.307 - Static pressure test.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Static pressure test. 7.307 Section 7.307... pressure test. (a) Test procedure. (1) The enclosure shall be internally pressurized to a minimum of 150 psig and the pressure maintained for a minimum of 10 seconds. (2) Following the pressure hold,...

  4. 30 CFR 7.307 - Static pressure test.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Static pressure test. 7.307 Section 7.307... pressure test. (a) Test procedure. (1) The enclosure shall be internally pressurized to a minimum of 150 psig and the pressure maintained for a minimum of 10 seconds. (2) Following the pressure hold,...

  5. 30 CFR 7.307 - Static pressure test.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Static pressure test. 7.307 Section 7.307... pressure test. (a) Test procedure. (1) The enclosure shall be internally pressurized to a minimum of 150 psig and the pressure maintained for a minimum of 10 seconds. (2) Following the pressure hold,...

  6. 30 CFR 7.104 - Internal static pressure test.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 30 Mineral Resources 1 2013-07-01 2013-07-01 false Internal static pressure test. 7.104 Section 7... Internal static pressure test. (a) Test procedures. (1) Isolate and seal each segment of the intake system... system or exhaust system to four times the maximum pressure observed in each segment during the tests...

  7. 30 CFR 7.104 - Internal static pressure test.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Internal static pressure test. 7.104 Section 7... Internal static pressure test. (a) Test procedures. (1) Isolate and seal each segment of the intake system... system or exhaust system to four times the maximum pressure observed in each segment during the tests...

  8. 30 CFR 7.104 - Internal static pressure test.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Internal static pressure test. 7.104 Section 7... Internal static pressure test. (a) Test procedures. (1) Isolate and seal each segment of the intake system... system or exhaust system to four times the maximum pressure observed in each segment during the tests...

  9. 30 CFR 7.104 - Internal static pressure test.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Internal static pressure test. 7.104 Section 7... Internal static pressure test. (a) Test procedures. (1) Isolate and seal each segment of the intake system... system or exhaust system to four times the maximum pressure observed in each segment during the tests...

  10. 30 CFR 7.104 - Internal static pressure test.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 30 Mineral Resources 1 2012-07-01 2012-07-01 false Internal static pressure test. 7.104 Section 7... Internal static pressure test. (a) Test procedures. (1) Isolate and seal each segment of the intake system... system or exhaust system to four times the maximum pressure observed in each segment during the tests...

  11. 14 CFR 33.64 - Pressurized engine static parts.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 1 2013-01-01 2013-01-01 false Pressurized engine static parts. 33.64... engine static parts. (a) Strength. The applicant must establish by test, validated analysis, or a combination of both, that all static parts subject to significant gas or liquid pressure loads for...

  12. 14 CFR 33.64 - Pressurized engine static parts.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Pressurized engine static parts. 33.64... engine static parts. (a) Strength. The applicant must establish by test, validated analysis, or a combination of both, that all static parts subject to significant gas or liquid pressure loads for...

  13. 14 CFR 33.64 - Pressurized engine static parts.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Pressurized engine static parts. 33.64... engine static parts. (a) Strength. The applicant must establish by test, validated analysis, or a combination of both, that all static parts subject to significant gas or liquid pressure loads for...

  14. 14 CFR 33.64 - Pressurized engine static parts.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Pressurized engine static parts. 33.64... engine static parts. (a) Strength. The applicant must establish by test, validated analysis, or a combination of both, that all static parts subject to significant gas or liquid pressure loads for...

  15. 14 CFR 27.1325 - Static pressure systems.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Static pressure systems. 27.1325 Section 27... AIRWORTHINESS STANDARDS: NORMAL CATEGORY ROTORCRAFT Equipment Instruments: Installation § 27.1325 Static pressure systems. (a) Each instrument with static air case connections must be vented so that the...

  16. 14 CFR 33.64 - Pressurized engine static parts.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 1 2012-01-01 2012-01-01 false Pressurized engine static parts. 33.64... engine static parts. (a) Strength. The applicant must establish by test, validated analysis, or a combination of both, that all static parts subject to significant gas or liquid pressure loads for...

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

    NASA Astrophysics Data System (ADS)

    Sindt, C. F.; Labrecque, J. F.

    1982-06-01

    A facility was developed to calibrate pressure transducers that are used in a gas mass flow facility. Both static and differential pressure transducers can be calibrated. An air dead weight tester is the standard for static transducers in the range from 3.8 to 4.5 MPa. An air dead weight tester is also the standard for the differential pressure transducers in the range of 2.5 kPa to 50 MPa; a cistern manometer. This, plus the uncertainties in the high pressure corrections to the cistern manometer and measurement of the mercury temperature, contributes plus or minus 690 ppm to the uncertainty of the differential pressure transducer calibrations.

  18. Miniature Flow-Direction/Pitot-Static Pressure Probes

    NASA Technical Reports Server (NTRS)

    Ashby, George C., Jr.; Coombs, David S.; Eves, John W.; Price, Howard E.; Vasquez, Peter

    1989-01-01

    Precision flow-direction/pitot-static pressure probes, ranging from 0.035 to 0.090 inch (0.89 to 2.29 mm) in outside diameter, successfully fabricated and calibrated for use in Langley 20-inch Mach 6 Tunnel. Probes simultaneously measure flow direction and static and pitot pressures in flow fields about configurations in hypersonic flow at temperatures up to 500 degree F (260 degree C).

  19. Terapascal static pressure generation with ultrahigh yield strength nanodiamond.

    PubMed

    Dubrovinskaia, Natalia; Dubrovinsky, Leonid; Solopova, Natalia A; Abakumov, Artem; Turner, Stuart; Hanfland, Michael; Bykova, Elena; Bykov, Maxim; Prescher, Clemens; Prakapenka, Vitali B; Petitgirard, Sylvain; Chuvashova, Irina; Gasharova, Biliana; Mathis, Yves-Laurent; Ershov, Petr; Snigireva, Irina; Snigirev, Anatoly

    2016-07-01

    Studies of materials' properties at high and ultrahigh pressures lead to discoveries of unique physical and chemical phenomena and a deeper understanding of matter. In high-pressure research, an achievable static pressure limit is imposed by the strength of available strong materials and design of high-pressure devices. Using a high-pressure and high-temperature technique, we synthesized optically transparent microballs of bulk nanocrystalline diamond, which were found to have an exceptional yield strength (~460 GPa at a confining pressure of ~70 GPa) due to the unique microstructure of bulk nanocrystalline diamond. We used the nanodiamond balls in a double-stage diamond anvil cell high-pressure device that allowed us to generate static pressures beyond 1 TPa, as demonstrated by synchrotron x-ray diffraction. Outstanding mechanical properties (strain-dependent elasticity, very high hardness, and unprecedented yield strength) make the nanodiamond balls a unique device for ultrahigh static pressure generation. Structurally isotropic, homogeneous, and made of a low-Z material, they are promising in the field of x-ray optical applications.

  20. Terapascal static pressure generation with ultrahigh yield strength nanodiamond

    PubMed Central

    Dubrovinskaia, Natalia; Dubrovinsky, Leonid; Solopova, Natalia A.; Abakumov, Artem; Turner, Stuart; Hanfland, Michael; Bykova, Elena; Bykov, Maxim; Prescher, Clemens; Prakapenka, Vitali B.; Petitgirard, Sylvain; Chuvashova, Irina; Gasharova, Biliana; Mathis, Yves-Laurent; Ershov, Petr; Snigireva, Irina; Snigirev, Anatoly

    2016-01-01

    Studies of materials’ properties at high and ultrahigh pressures lead to discoveries of unique physical and chemical phenomena and a deeper understanding of matter. In high-pressure research, an achievable static pressure limit is imposed by the strength of available strong materials and design of high-pressure devices. Using a high-pressure and high-temperature technique, we synthesized optically transparent microballs of bulk nanocrystalline diamond, which were found to have an exceptional yield strength (~460 GPa at a confining pressure of ~70 GPa) due to the unique microstructure of bulk nanocrystalline diamond. We used the nanodiamond balls in a double-stage diamond anvil cell high-pressure device that allowed us to generate static pressures beyond 1 TPa, as demonstrated by synchrotron x-ray diffraction. Outstanding mechanical properties (strain-dependent elasticity, very high hardness, and unprecedented yield strength) make the nanodiamond balls a unique device for ultrahigh static pressure generation. Structurally isotropic, homogeneous, and made of a low-Z material, they are promising in the field of x-ray optical applications. PMID:27453944

  1. 14 CFR 25.1325 - Static pressure systems.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY AIRPLANES Equipment Instruments: Installation § 25.1325 Static... and true ambient atmospheric static pressure is not changed when the airplane is exposed to the... materials used are durable, suitable for the purpose intended, and protected against corrosion; and (2)...

  2. 14 CFR 25.1325 - Static pressure systems.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY AIRPLANES Equipment Instruments: Installation § 25.1325 Static... and true ambient atmospheric static pressure is not changed when the airplane is exposed to the... materials used are durable, suitable for the purpose intended, and protected against corrosion; and (2)...

  3. 14 CFR 25.1325 - Static pressure systems.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY AIRPLANES Equipment Instruments: Installation § 25.1325 Static... and true ambient atmospheric static pressure is not changed when the airplane is exposed to the... materials used are durable, suitable for the purpose intended, and protected against corrosion; and (2)...

  4. 14 CFR 25.1325 - Static pressure systems.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY AIRPLANES Equipment Instruments: Installation § 25.1325 Static... and true ambient atmospheric static pressure is not changed when the airplane is exposed to the... materials used are durable, suitable for the purpose intended, and protected against corrosion; and (2)...

  5. 14 CFR 25.1325 - Static pressure systems.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY AIRPLANES Equipment Instruments: Installation § 25.1325 Static... and true ambient atmospheric static pressure is not changed when the airplane is exposed to the... materials used are durable, suitable for the purpose intended, and protected against corrosion; and (2)...

  6. The effect of static pressure on the inertial cavitation threshold.

    PubMed

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

    2012-08-01

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

  7. 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.

  8. Static filling pressure in patients during induced ventricular fibrillation.

    PubMed

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

    2003-12-01

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

  9. 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.

  10. 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.

  11. 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.

  12. Experimental cavity pressure measurements at subsonic and transonic speeds. Static-pressure results

    NASA Technical Reports Server (NTRS)

    Plentovich, E. B.; Stallings, Robert L., Jr.; Tracy, M. B.

    1993-01-01

    An experimental investigation was conducted to determine cavity flow-characteristics at subsonic and transonic speeds. A rectangular box cavity was tested in the Langley 8-Foot Transonic Pressure Tunnel at Mach numbers from 0.20 to 0.95 at a unit Reynolds number of approximately 3 x 10(exp 6) per foot. The boundary layer approaching the cavity was turbulent. Cavities were tested over a range of length-to-depth ratios (l/h) of 1 to 17.5 for cavity width-to-depth ratios of 1, 4, 8, and 16. Fluctuating- and static-pressure data in the cavity were obtained; however, only static-pressure data is analyzed. The boundaries between the flow regimes based on cavity length-to-depth ratio were determined. The change to transitional flow from open flow occurs at l/h at approximately 6-8 however, the change from transitional- to closed-cavity flow occurred over a wide range of l/h and was dependent on Mach number and cavity configuration. The change from closed to open flow as found to occur gradually. The effect of changing cavity dimensions showed that if the vlaue of l/h was kept fixed but the cavity width was decreased or cavity height was increased, the cavity pressure distribution tended more toward a more closed flow distribution.

  13. Measurement and analysis of static pressure field in a torque converter pump

    SciTech Connect

    By, R.R.; Lakshminarayana, B.

    1995-03-01

    In this paper, the static pressure field and performance parameters of a torque converter pump are measured, analyzed, and interpreted under three turbine/pump speed ratio conditions (0, 0.6, and 0.8). A potential flow code is used to predict the static pressure distribution. Results show that: (1) centrifugal force has a dominant effect on the static pressure rise in the pump; (2) the static pressure field is generally poor at the core section; and (3) the potential flow code can fairly well predict the static pressure distribution at the blade mid-span, but not at the core and shell sections.

  14. 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.

  15. 30 CFR 550.1153 - When must I conduct a static bottomhole pressure survey?

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 30 Mineral Resources 2 2013-07-01 2013-07-01 false When must I conduct a static bottomhole... Gas Production Requirements. Well Tests and Surveys § 550.1153 When must I conduct a static bottomhole pressure survey? (a) You must conduct a static bottomhole pressure survey under the following...

  16. 30 CFR 250.1153 - When must I conduct a static bottomhole pressure survey?

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 2 2010-07-01 2010-07-01 false When must I conduct a static bottomhole... Requirements Well Tests and Surveys § 250.1153 When must I conduct a static bottomhole pressure survey? (a) You must conduct a static bottomhole pressure survey under the following conditions: If you have . . ....

  17. 30 CFR 550.1153 - When must I conduct a static bottomhole pressure survey?

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 30 Mineral Resources 2 2012-07-01 2012-07-01 false When must I conduct a static bottomhole... Gas Production Requirements. Well Tests and Surveys § 550.1153 When must I conduct a static bottomhole pressure survey? (a) You must conduct a static bottomhole pressure survey under the following...

  18. 30 CFR 250.1153 - When must I conduct a static bottomhole pressure survey?

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 30 Mineral Resources 2 2011-07-01 2011-07-01 false When must I conduct a static bottomhole... static bottomhole pressure survey? (a) You must conduct a static bottomhole pressure survey under the following conditions: If you have . . . Then you must conduct . . . (1) A new producing reservoir A...

  19. 30 CFR 550.1153 - When must I conduct a static bottomhole pressure survey?

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 30 Mineral Resources 2 2014-07-01 2014-07-01 false When must I conduct a static bottomhole... Gas Production Requirements. Well Tests and Surveys § 550.1153 When must I conduct a static bottomhole pressure survey? (a) You must conduct a static bottomhole pressure survey under the following...

  20. Pressure and velocity profiles in a static mechanical hemilarynx model.

    PubMed

    Alipour, Fariborz; Scherer, Ronald C

    2002-12-01

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

  1. Effects of static fingertip loading on carpal tunnel pressure

    NASA Technical Reports Server (NTRS)

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

    1997-01-01

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

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

    NASA Technical Reports Server (NTRS)

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

    2014-01-01

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

  3. Sideslip-induced static pressure errors in flight-test measurements

    NASA Technical Reports Server (NTRS)

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

    1990-01-01

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

  4. Flexible Piezoelectric-Induced Pressure Sensors for Static Measurements Based on Nanowires/Graphene Heterostructures.

    PubMed

    Chen, Zefeng; Wang, Zhao; Li, Xinming; Lin, Yuxuan; Luo, Ningqi; Long, Mingzhu; Zhao, Ni; Xu, Jian-Bin

    2017-04-05

    The piezoelectric effect is widely applied in pressure sensors for the detection of dynamic signals. However, these piezoelectric-induced pressure sensors have challenges in measuring static signals which are based on the transient flow of electrons in external load as driven by the piezopotential arisen from dynamic stress. Here, we present a pressure sensor with nanowires/graphene heterostructures for static measurements based on the synergistic mechanisms between strain-induced polarization charges in piezoelectric nanowires and the caused change of carrier scattering in graphene. Compared to the conventional piezoelectric nanowire or graphene pressure sensors, this sensor is capable of measuring static pressures with a sensitivity up to 9.4×10(-3) kPa(-1) and a fast response time down to 5-7 ms. This demonstration of pressure sensors shows great potential in the applications of electronic skin and wearable devices.

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

    NASA Astrophysics Data System (ADS)

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

    In this study, special attention is directed to static pressure fluctuation in a sirocco fan for a car air-conditioning system, because it is expected that there is a close connection between the fluid noise and the pressure fluctuation. The final purpose of this study is to clarify the relationship between the static pressure fluctuation between fan blades and the sound noise emitted to the outside of the fan, and to develop an air-conditioning system with highly low noise level. For this purpose, first of all, a new micro probe for the measurement of static pressure fluctuation has been developed. This new micro probe is composed of an L-type static pressure tube (the outer diameter is 0.5 mm and the inner diameter is 0.34 mm) and a very small pressure transducer. This probe exhibits a flat frequency response until approximately 2,000 Hz, and it is set between the blades of the fan rotating at 1,500 rpm. The measurements of the static pressure fluctuation between the blades have been performed, and the intensity of sound source was quantified from the second derivative of the phase-averaged static pressure fluctuation signals on the basis of Ribner's formula (Ribner 1962). The experiments have been made in two different modes, i.e., the cooling mode (FACE MODE) and the heating mode (FOOT MODE). It is shown that the static pressure increases rapidly as the blade approaches to the nose of the casing. It is also found that the sound source for FACE MODE shows the larger value than that for FOOT MODE as a whole. In particular, the largest intensity of sound source is observed when the blade approaches to the nose. From these results, it is confirmed that the present new static pressure probe is useful to specify the distributions of sound source in a sirocco fan.

  6. Adjoint Optimization of Multistage Axial Compressor Blades with Static Pressure Constraint at Blade Row Interface

    NASA Astrophysics Data System (ADS)

    Yu, Jia; Ji, Lucheng; Li, Weiwei; Yi, Weilin

    2016-06-01

    Adjoint method is an important tool for design refinement of multistage compressors. However, the radial static pressure distribution deviates during the optimization procedure and deteriorates the overall performance, producing final designs that are not well suited for realistic engineering applications. In previous development work on multistage turbomachinery blade optimization using adjoint method and thin shear-layer N-S equations, the entropy production is selected as the objective function with given mass flow rate and total pressure ratio as imposed constraints. The radial static pressure distribution at the interfaces between rows is introduced as a new constraint in the present paper. The approach is applied to the redesign of a five-stage axial compressor, and the results obtained with and without the constraint on the radial static pressure distribution at the interfaces between rows are discussed in detail. The results show that the redesign without the radial static pressure distribution constraint (RSPDC) gives an optimal solution that shows deviations on radial static pressure distribution, especially at rotor exit tip region. On the other hand, the redesign with the RSPDC successfully keeps the radial static pressure distribution at the interfaces between rows and make sure that the optimization results are applicable in a practical engineering design.

  7. Exact solutions: neutral and charged static perfect fluids with pressure

    NASA Astrophysics Data System (ADS)

    Bijalwan, Naveen

    2012-01-01

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

  8. 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.

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

    NASA Technical Reports Server (NTRS)

    1946-01-01

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

  10. Effect of revised high-heeled shoes on foot pressure and static balance during standing.

    PubMed

    Bae, Young-Hyeon; Ko, Mansoo; Park, Young-Soul; Lee, Suk-Min

    2015-04-01

    [Purpose] The purpose of this study was to investigate the effects of revised high-heeled shoes on the foot pressure ratio and static balance during standing. [Subjects and Methods] A single-subject design was used, 15 healthy women wearing revised high-heeled shoes and general high-heeled shoes in a random order. The foot pressure ratio and static balance scores during standing were measured using a SpaceBalance 3D system. [Results] Forefoot and rearfoot pressures were significantly different between the 2 types of high-heeled shoes. Under the 3 conditions tested, the static balance score was higher for the revised high-heeled shoes than for the general high-heeled shoes, but this difference was not statistically significant. [Conclusion] Revised high-heeled shoes are preferable to general high-heeled shoes, as they result in normalization of normalized foot pressure and a positive effect on static balance.

  11. Non-catalytic synthesis of diamond from amorphous carbon at high static pressure

    NASA Astrophysics Data System (ADS)

    Higashi, K.; Onodera, A.

    1986-05-01

    Amorphous carbon prepared from furfuryl alcohol resin was studied under static high pressure above 10 GPa without planned addition of catalyst. Diamond can be formed at temperatures lower than required for the catalytic process.

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

    NASA Technical Reports Server (NTRS)

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

    1993-01-01

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

  13. 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.

  14. Free-stream static pressure measurements in the Longshot hypersonic wind tunnel and sensitivity analysis

    NASA Astrophysics Data System (ADS)

    Grossir, Guillaume; Van Hove, Bart; Paris, Sébastien; Rambaud, Patrick; Chazot, Olivier

    2016-05-01

    The performance of fast-response slender static pressure probes is evaluated in the short-duration, cold-gas, VKI Longshot hypersonic wind tunnel. Free-stream Mach numbers range between 9.5 and 12, and unit Reynolds numbers are within 3-10 × 106/m. Absolute pressure sensors are fitted within the probes, and an inexpensive calibration method, suited to low static pressure environments (200-1000 Pa), is described. Transfer functions relating the probe measurements p w to the free-stream static pressure p ∞ are established for the Longshot flow conditions based on numerical simulations. The pressure ratios p w / p ∞ are found to be close to unity for both laminar and turbulent boundary layers. Weak viscous effects characterized by small viscous interaction parameters {bar{χ }}<1.5 are confirmed experimentally for probe aspect ratios of L/ D > 16.5 by installing multiple pressure sensors in a single probe. The effect of pressure orifice geometry is also evaluated experimentally and found to be negligible for either straight or chamfered holes, 0.6-1 mm in diameter. No sensitivity to probe angle of attack could be evidenced for α < 0.33°. Pressure measurements are compared to theoretical predictions assuming an isentropic nozzle flow expansion. Significant deviations from this ideal case and the Mach 14 contoured nozzle design are uncovered. Validation of the static pressure measurements is obtained by comparing shock wave locations on Schlieren photographs to numerical predictions using free-stream properties derived from the static pressure probes. While these results apply to the Longshot wind tunnel, the present methodology and sensitivity analysis can guide similar investigations for other hypersonic test facilities.

  15. 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.

  16. Impacts of static pressure set level on HVAC energy consumption and indoor conditions

    SciTech Connect

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

    1997-12-31

    Air static pressure must be maintained at a certain level leaving the air-handling 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 device in a constant-volume (CV) system, (2) a malfunctioning control device in a variable-air-volume (VAV) system, and (3) fear of failure to maintain room temperature. High static pressure often develops excessive damper leakage in older mixing boxes. This results in an appropriate mixing of hot and cold air for dual-duct systems, excessive reheat in single-duct systems, and an excessive amount of air entering the space. Consequently, the actual fan power and heating and cooling energy consumption all become significantly higher than the design values. Even worse, the system may not be able to maintain room conditions due to unwanted simultaneous heating and cooling and may be noisy due to the excessive static pressure. This paper proposed to control the hot duct pressure and the variable-frequency drives (VFDs) to control the fan static, i.e., the cold duct pressure for dual-duct air-handling units. Both a theoretical analysis and results from a case study are presented in this paper.

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

    PubMed

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

    2003-04-15

    The surgical removal of the post-hepatic septum (PHS) in the tegu lizard, Tupinambis merianae, significantly reduces resting lung volume (V(Lr)) and maximal lung volume (V(Lm)) when compared with tegus with intact PHS. Standardised for body mass (M(B)), static lung compliance was significantly less in tegus without PHS. Pleural and abdominal pressures followed, like ventilation, a biphasic pattern. In general, pressures increased during expiration and decreased during inspiration. However, during expiration pressure changes showed a marked intra- and interindividual variation. The removal of the PHS resulted in a lower cranio-caudal intracoelomic pressure differential, but had no effect on the general pattern of pressure changes accompanying ventilation. These results show that a perforated PHS that lacks striated muscle has significant influence on static breathing mechanics in Tupinambis and by analogy provides valuable insight into similar processes that led to the evolution of the mammalian diaphragm.

  18. Correcting "static" measurements of vapor pressure for time dependence due to diffusion and decomposition.

    PubMed

    Berg, Robert F

    2015-12-10

    The static method for measuring vapor pressure assumes that the sample is pure and that its temperature is steady and uniform. In practice, the measured pressure may be time dependent due to evaporative cooling after pumping on the sample, transpiration of the sample in a temperature gradient, or diffusion of an impurity out of the sample. An impurity cannot be avoided if the sample is decomposing. This article identifies and quantifies various causes of time dependence, and it includes an analysis that can obtain the vapor pressure from the time-dependent pressure of a decomposing sample. The analysis was applied to measurements of TEMAH (tetrakisethylmethylaminohafnium), whose decomposition continuously generated a volatile impurity. The corrected vapor pressures obtained for three TEMAH samples at 39 °C agreed to within ±1 %, even though the partial pressure of the impurity was as much as 7 times larger.

  19. Cygnus Pressurized Cargo Module (PCM) Flight Inertial Load Static Tests

    NASA Astrophysics Data System (ADS)

    Murgia, Giovanni; Mancini, Simone; Palmieri, Paolo; Rutigliano, Luigi

    2012-07-01

    Cygnus PCM Flight Inertial Load Static Test campaign has been performed by Thales Alenia Space - Italy (TAS-I) to achieve the Static Qualification of its Primary Structure. A “Proto-flight Approach” has been followed (as per [1] and [2]), thus the first flight unit, the PCM0, has been tested up to qualification level (qualification/acceptance factor equivalent to 1.2 [1]). The PCM0 has been constrained to a dummy Service Module (the second member of Cygnus Spacecraft), representative in terms of interfaces provisions, and flight load conditions have been reproduced with proper forces that have been applied by means of hydraulic jacks at internal PCM secondary structure interfaces. Test load cases have been defined in order to simulate load paths and relevant stress fields associated to the worst flight load conditions by using the FE model analyses. Tests have been monitored by means of gauges and displacement transducers and results have been utilized to correlate the PCM FEM following [3] requirements.

  20. Subharmonic contrast microbubble signals for noninvasive pressure estimation under static and dynamic flow conditions.

    PubMed

    Halldorsdottir, Valgerdur G; Dave, Jaydev K; Leodore, Lauren M; Eisenbrey, John R; Park, Suhyun; Hall, Anne L; Thomenius, Kai; Forsberg, Flemming

    2011-07-01

    Our group has proposed the concept of subharmonic aided pressure estimation (SHAPE) utilizing microbubble-based ultrasound contrast agent signals for the noninvasive estimation of hydrostatic blood pressures. An experimental system for in vitro SHAPE was constructed based on two single-element transducers assembled confocally at a 60 degree angle to each other. Changes in the first, second and subharmonic amplitudes of five different ultrasound contrast agents were measured in vitro at static hydrostatic pressures from 0-186 mmHg, acoustic pressures from 0.35-0.60 MPa peak-to-peak and frequencies of 2.5-6.6 MHz. The most sensitive agent and optimal parameters for SHAPE were determined using linear regression analysis and implemented on a Logiq 9 scanner (GE Healthcare, Milwaukee, WI). This implementation of SHAPE was then tested under dynamic-flow conditions and compared to pressure-catheter measurements. Over the pressure range studied, the first and second harmonic amplitudes reduced approximately 2 dB for all contrast agents. Over the same pressure range, the subharmonic amplitudes decreased by 9-14 dB and excellent linear regressions were achieved with the hydrostatic pressure variations (r = 0.98, p < 0.001). Optimal sensitivity was achieved at a transmit frequency of 2.5 MHz and acoustic pressure of 0.35 MPa using Sonazoid (GE Healthcare, Oslo, Norway). A Logiq 9 scanner was modified to implement SHAPE on a convex transducer with a frequency range from 1.5-4.5 MHz and acoustic pressures from 0-3.34 MPa. Results matched the pressure catheter (r2 = 0.87). In conclusion, subharmonic contrast signals are a good indicator of hydrostatic pressure. Out of the five ultrasound contrast agents tested, Sonazoid was the most sensitive for subharmonic pressure estimation. Real-time SHAPE has been implemented on a commercial scanner and offers the possibility of allowing pressures in the heart and elsewhere to be obtained noninvasively.

  1. Static Pressure Distribution on Long Cylinders as Function of Angle of Yaw and Reynolds Number,

    DTIC Science & Technology

    1983-07-01

    pressure coefficient around a perpendicularly aligned cylinder xiv 1. INTRODUCTION The problem addressed in this investigation is that of the static...pressure distribution developed on the surface of a long circular cylinder immersed in a laminar flow at small angles of yaw. The interest in this problem ...cylinder. The problem of flow over yawed cylinders or cylinders at angle of attack first attracted attention in the 1950’s. At that time, r esearch was

  2. Sideslip-induced static pressure errors in flight-test measurements

    NASA Technical Reports Server (NTRS)

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

    1990-01-01

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

  3. 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.

  4. 33 CFR 183.580 - Static pressure test for fuel tanks.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 2 2010-07-01 2010-07-01 false Static pressure test for fuel tanks. 183.580 Section 183.580 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) BOATING SAFETY BOATS AND ASSOCIATED EQUIPMENT Fuel Systems Tests § 183.580...

  5. 33 CFR 183.580 - Static pressure test for fuel tanks.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 33 Navigation and Navigable Waters 2 2011-07-01 2011-07-01 false Static pressure test for fuel tanks. 183.580 Section 183.580 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) BOATING SAFETY BOATS AND ASSOCIATED EQUIPMENT Fuel Systems Tests § 183.580...

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

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 33 Navigation and Navigable Waters 2 2012-07-01 2012-07-01 false Static pressure test for fuel tanks. 183.580 Section 183.580 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) BOATING SAFETY BOATS AND ASSOCIATED EQUIPMENT Fuel Systems Tests § 183.580...

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

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 33 Navigation and Navigable Waters 2 2014-07-01 2014-07-01 false Static pressure test for fuel tanks. 183.580 Section 183.580 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) BOATING SAFETY BOATS AND ASSOCIATED EQUIPMENT Fuel Systems Tests § 183.580...

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

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 33 Navigation and Navigable Waters 2 2013-07-01 2013-07-01 false Static pressure test for fuel tanks. 183.580 Section 183.580 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) BOATING SAFETY BOATS AND ASSOCIATED EQUIPMENT Fuel Systems Tests § 183.580...

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

    NASA Technical Reports Server (NTRS)

    Fischer, A. K.

    1968-01-01

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

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

    PubMed

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

    2012-10-01

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

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

    PubMed

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

    2011-11-01

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

  12. Fingertip skin-inspired microstructured ferroelectric skins discriminate static/dynamic pressure and temperature stimuli.

    PubMed

    Park, Jonghwa; Kim, Marie; Lee, Youngoh; Lee, Heon Sang; Ko, Hyunhyub

    2015-10-01

    In human fingertips, the fingerprint patterns and interlocked epidermal-dermal microridges play a critical role in amplifying and transferring tactile signals to various mechanoreceptors, enabling spatiotemporal perception of various static and dynamic tactile signals. Inspired by the structure and functions of the human fingertip, we fabricated fingerprint-like patterns and interlocked microstructures in ferroelectric films, which can enhance the piezoelectric, pyroelectric, and piezoresistive sensing of static and dynamic mechanothermal signals. Our flexible and microstructured ferroelectric skins can detect and discriminate between multiple spatiotemporal tactile stimuli including static and dynamic pressure, vibration, and temperature with high sensitivities. As proof-of-concept demonstration, the sensors have been used for the simultaneous monitoring of pulse pressure and temperature of artery vessels, precise detection of acoustic sounds, and discrimination of various surface textures. Our microstructured ferroelectric skins may find applications in robotic skins, wearable sensors, and medical diagnostic devices.

  13. Fingertip skin–inspired microstructured ferroelectric skins discriminate static/dynamic pressure and temperature stimuli

    PubMed Central

    Park, Jonghwa; Kim, Marie; Lee, Youngoh; Lee, Heon Sang; Ko, Hyunhyub

    2015-01-01

    In human fingertips, the fingerprint patterns and interlocked epidermal-dermal microridges play a critical role in amplifying and transferring tactile signals to various mechanoreceptors, enabling spatiotemporal perception of various static and dynamic tactile signals. Inspired by the structure and functions of the human fingertip, we fabricated fingerprint-like patterns and interlocked microstructures in ferroelectric films, which can enhance the piezoelectric, pyroelectric, and piezoresistive sensing of static and dynamic mechanothermal signals. Our flexible and microstructured ferroelectric skins can detect and discriminate between multiple spatiotemporal tactile stimuli including static and dynamic pressure, vibration, and temperature with high sensitivities. As proof-of-concept demonstration, the sensors have been used for the simultaneous monitoring of pulse pressure and temperature of artery vessels, precise detection of acoustic sounds, and discrimination of various surface textures. Our microstructured ferroelectric skins may find applications in robotic skins, wearable sensors, and medical diagnostic devices. PMID:26601303

  14. 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.

  15. Plantar pressures in individuals with normal and pronated feet according to static squat depths.

    PubMed

    Koh, Da Hyun; Lee, Jong Dae; Kim, Kyoung

    2015-09-01

    [Purpose] The purpose of the present study was to investigate differences in plantar pressure between individuals with normal and pronated feet according to 3 static squat depths. [Subjects and Methods] Study subjects were 10 young adults with normal and pronated feet. Plantar pressures were measured in the standing position and static squat positions at 45° (semi-squat) and 90° (half-squat) knee flexion using the F-Mat. Subjects' plantar pressures were analyzed by dividing the foot into 4 areas: forefoot medial, forefoot lateral, midfoot, and heel. [Results] In the half-squat position, the pronated foot group showed a higher foot pressure in the forefoot medial than was seen in the normal group, whereas the normal group exhibited a higher foot pressure in the heel than was seen in the pronated foot group. [Conclusion] An increase in squat depth led to the transfer of plantar pressure to the heel in normal feet and to the forefoot medial in pronated feet.

  16. Plantar pressures in individuals with normal and pronated feet according to static squat depths

    PubMed Central

    Koh, Da Hyun; Lee, Jong Dae; Kim, Kyoung

    2015-01-01

    [Purpose] The purpose of the present study was to investigate differences in plantar pressure between individuals with normal and pronated feet according to 3 static squat depths. [Subjects and Methods] Study subjects were 10 young adults with normal and pronated feet. Plantar pressures were measured in the standing position and static squat positions at 45° (semi-squat) and 90° (half-squat) knee flexion using the F-Mat. Subjects’ plantar pressures were analyzed by dividing the foot into 4 areas: forefoot medial, forefoot lateral, midfoot, and heel. [Results] In the half-squat position, the pronated foot group showed a higher foot pressure in the forefoot medial than was seen in the normal group, whereas the normal group exhibited a higher foot pressure in the heel than was seen in the pronated foot group. [Conclusion] An increase in squat depth led to the transfer of plantar pressure to the heel in normal feet and to the forefoot medial in pronated feet. PMID:26504304

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

    NASA Astrophysics Data System (ADS)

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

    2006-12-01

    About 50 years ago, shock wave researchers were confounded by the apparent rapidity of shock-induced phase transformations and invoked special mechanisms as an explanation. Some workers speculatively interpret shock wave data as indicative of very rapid reconstructive phase transformations of minerals at modest temperatures. The belief that kinetic effects are negligible has justified the use of microsecond duration shock recovery experiments to interpret much longer duration shock effects in terrestrial impact craters and in meteorites. Here we summarize the extensive evidence that phase transformations under shock compression are governed by the same kinetics as phase transitions under static compression. Hugoniot measurements on quartz and feldspars have been interpreted as indicating phase transitions to dense phases at pressures near 35 GPa. Release adiabat measurements imply that these phases persist on release of pressure down to about 7 GPa, below which there is expansion to a final density appropriate to a glass. Microsecond-duration shock recovery experiments support this interpretation; a low density amorphous phase (diaplectic glass) is recovered. A similar effect is observed in static compression experiments conducted at room temperature at a lower pressure, 12-15 GPa. The pressure difference is a kinetic effect; the transition requires higher shock pressures (implying higher shock temperatures) to run to completion on a microsecond time scale. Direct evidence for kinetic effects on the tectosilicate transformation is found in studies of naturally shocked meteorites that contain melt veins. When the melt veins solidify under pressure, the resultant mineralogy together with vein cooling calculations constrains the shock pressure-time history. In some samples, in which the shock pressure is constrained by vein mineralogy to a range of 17-25 Gpa, one may observe the presence of diaplectic glass in only near-vein regions heated by conduction from the vein

  18. 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.

  19. 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

    2015-07-08

    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.

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

    NASA Technical Reports Server (NTRS)

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

    1995-01-01

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

  1. 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.

  2. The influence of age on pressure perception of static and moving two-point discrimination in normal subjects.

    PubMed

    Kaneko, Atsushi; Asai, Noriyoshi; Kanda, Tadashi

    2005-01-01

    The purpose of the present study was to determine the effect of age on digital pressure perception as measured by two-point discrimination (2PD) testing. The subjects were 177 normal volunteers ranging in age from 20 to 79 years. Perceptible pressure of static and moving 2PD was measured on the index finger and little finger, using the Pressure-specifying Sensory Device. The threshold of pressure perception increased significantly with advancing age in both static and moving 2PD tests. There was a marked increase in subjects older than 60 years. Pressure perception was significantly higher for static 2PD than for moving 2PD in subjects 70-79 years of age. The threshold of pressure perception for static and moving 2PD gradually increased with advancing age, and was markedly elevated in subjects older than 60 years.

  3. Numerical Predictions of Static-Pressure-Error Corrections for a Modified T-38C Aircraft

    DTIC Science & Technology

    2014-12-15

    pc = pressure correction sic = static indicated corrected ∞ = freestream ⊥ = wall normal I. Introduction T HE fleet of T-38C aircraft at the U.S. Air...but the more modern work of Latif et al. [11] demonstrated that compensated Pitot-static probes can be simulated accurately for subsonic and...Cosmic Gas Dynamics,” Astronomy and Astrophysics , Vol. 108, No. 1, 1982, pp. 76–84. [26] Magnus, R., andYoshihara,H., “Inviscid Transonic FlowoverAirfoils

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

    NASA Technical Reports Server (NTRS)

    Rossow, Vernon J. (Inventor)

    1993-01-01

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

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

    PubMed

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

    2013-09-01

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

  6. In situ electrical conductivity measurements of H2O under static pressure up to 28 GPa

    NASA Astrophysics Data System (ADS)

    Liu, Bao; Gao, Yang; Han, Yonghao; Ma, Yanzhang; Gao, Chunxiao

    2016-08-01

    The in situ electrical conductivity measurements on water in both solid state and liquid state were performed under pressure up to 28 GPa and temperature from 77 K to 300 K using a microcircuit fabricated on a diamond anvil cell (DAC). Water chemically ionization mainly contributes to electrical conduction in liquid state, which is in accord with the results obtained under dynamic pressure. Energy band theory of liquid water was used to understand effect of static pressure on electrical conduction of water. The electric conductivity of H2O decreased discontinuously by four orders of magnitude at 0.7-0.96 GPa, indicating water frozen at this P-T condition. Correspondingly, the conduction of H2O in solid state is determined by arrangement and bending of H-bond in ice VI and ice VII. Based on Jaccard theory, we have concluded that the charge carriers of ice are already existing ions and Bjerrum defects.

  7. 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

  8. Analysis of Fluctuating Static Pressure Measurements in the National Transonic Facility

    NASA Technical Reports Server (NTRS)

    Igoe, William B.

    1996-01-01

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

  9. 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.

  10. Wave Reflection and Central Aortic Pressure Are Increased in Response to Static and Dynamic Muscle Contraction at Comparable Workloads

    DTIC Science & Technology

    2008-02-01

    wave reflec- tion is an important determinant of the central blood pressure response during forearm muscle contractions. tension-time index; exercise ...pressor reflex; blood pressure THE PRESSOR RESPONSE to exercise had been thought to be greater as a result of static muscle contraction compared with...equivalent peripheral blood pressure response to forearm and lower body exercise may result in very different central aortic pressures due to differential

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

    SciTech Connect

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

    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.

  12. Wave reflection and central aortic pressure are increased in response to static and dynamic muscle contraction at comparable workloads.

    PubMed

    Edwards, David G; Mastin, Corey R; Kenefick, Robert W

    2008-02-01

    We determined the effects of static and dynamic muscle contraction at equivalent workloads on central aortic pressure and wave reflection. At random, 14 healthy men and women (23 +/- 5 yr of age) performed a static handgrip forearm contraction [90 s at 30% of maximal voluntary contraction (MVC)], dynamic handgrip contractions (1 contraction/s for 180 s at 30% MVC), and a control trial. During static and dynamic trials, tension-time index was controlled by holding peak tension constant. Measurements of brachial artery blood pressure and the synthesis of a central aortic pressure waveform (by radial artery applanation tonometry and generalized transfer function) were conducted at baseline, during each trial, and during 1 min of postexercise ischemia (PEI). Aortic augmentation index (AI), an index of wave reflection, was calculated from the aortic pressure waveform. AI increased during both static and dynamic trials (static, 5.2 +/- 3.1 to 11.8 +/- 3.4%; dynamic, 5.8 +/- 3.0 to 13.3 +/- 3.4%; P < 0.05) and further increased during PEI (static, 18.5 +/- 3.1%; dynamic, 18.6 +/- 2.9%; P < 0.05). Peripheral and central systolic and diastolic pressures increased (P < 0.05) during both static and dynamic trials and remained elevated during PEI. AI and pressure responses did not differ between static and dynamic trials. Peripheral and central pressures increased similarly during static and dynamic contraction; however, the rise in central systolic pressure during both conditions was augmented by increased wave reflection. The present data suggest that wave reflection is an important determinant of the central blood pressure response during forearm muscle contractions.

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

    PubMed

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

    2010-06-01

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

  14. 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.

  15. Miniaturization techniques for obtaining static pressures comparable to the pressure at the center of the earth: X-ray diffraction at 416 GPa

    NASA Astrophysics Data System (ADS)

    Ruoff, Arthur L.; Xia, Hui; Luo, Huan; Vohra, Yogesh K.

    1990-12-01

    X-ray diffraction studies on tungsten and molybdenum were performed, using a 4-μm-diam x-ray beam, to very high pressures, with the pressures being obtained from the measured lattice parameters and isothermal equations of state of tungsten and molybdenum deduced from shock data. The bcc structure persists to the highest pressure, 378 GPa in tungsten, and 416 GPa in molybdenum. The static pressures generated and measured here exceed the pressure of 361 GPa at the center of the earth, the first time that this has been achieved and measured with a calibrated pressure scale. The details of the pressure profile at 335 GPa are shown and are of great use in designing anvils for future research. It is noted that the maximum pressures attained by x-ray diffraction with beveled anvils varies linearly with D-1/2 where D is the diameter of the flat suggesting that, perhaps, even higher pressures are possible with further miniaturization. A scaling law is used to calculate the minimum correction due to the presence of nonhydrostatic stress.

  16. The physics of pressure variation in microchannels within corotating or static discs

    NASA Astrophysics Data System (ADS)

    Guha, Abhijit; Sengupta, Sayantan

    2016-10-01

    We formulate a comprehensive analysis for the radial pressure variation in flow through microchannels within corotating (or static) discs, which is important for its fundamental value and application potential in macrofluidic and microfluidic devices. The uniqueness and utility of the present approach emanate from our ability to describe the physics completely in terms of non-dimensional numbers and to determine quantitatively the separate roles of inertia, centrifugal force, Coriolis force, and viscous effects in the overall radial pressure difference (Δpio). It is established here that the aspect ratio (ratio of inter-disc spacing and disc radius) plays only a secondary role as an independent parameter, its major role being contained within a newly identified dynamic similarity number (Ds). For radial inflow, it is shown that the magnitude of Δpio decreases monotonically as the tangential speed ratio (γ) increases but exhibits a minima when Ds is varied. For radial outflow, it is shown that Δpio increases monotonically as the flow coefficient (ϕ) decreases but evinces a maxima when Ds is varied. It is further shown that for the radial inflow case, the minima in the magnitude of Δpio exist even when the rotational speed of the discs is reduced to zero (static discs). The demonstrated existence of these extrema (i.e., minima for radial inflow and maxima for radial outflow) creates the scope for device optimization.

  17. Modeling and testing of static pressure within an optical fiber cable spool using distributed fiber Bragg gratings

    NASA Astrophysics Data System (ADS)

    Ma, Chengju; Ren, Liyong; Qu, Enshi; Tang, Feng; Liang, Quan

    2012-11-01

    Based on the force analysis, we establish a theoretical model to study the static pressure distribution of the fiber cable spool for the fiber optic guided missile (FOG-M). Simulations indicate that for each fiber layer in the fiber cable spool, the applied static pressure on it asymptotically converges as the number of fiber layers increases. Using the distributed fiber Bragg grating (FBG) sensing technique, the static pressure of fiber cable layers in the spool on the cable winding device was measured. Experiments show that the Bragg wavelength of FBG in every layer varies very quickly at the beginning and then becomes gently as the subsequent fiber cable was twisted onto the spool layer by layer. Theoretical simulations agree qualitatively with experimental results. This technology provides us a real-time method to monitor the pressure within the fiber cable layer during the cable winding process.

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

    SciTech Connect

    Brower, K.R.; Davis, L.L.; Naud, D.L.; Wang, J.

    1998-12-31

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

  19. Stresses and Displacements in Steel-Lined Pressure Tunnels and Shafts in Anisotropic Rock Under Quasi-Static Internal Water Pressure

    NASA Astrophysics Data System (ADS)

    Pachoud, Alexandre J.; Schleiss, Anton J.

    2016-04-01

    Steel-lined pressure tunnels and shafts are constructed to convey water from reservoirs to hydroelectric power plants. They are multilayer structures made of a steel liner, a cracked backfill concrete layer, a cracked or loosened near-field rock zone and a sound far-field rock zone. Designers often assume isotropic behavior of the far-field rock, considering the most unfavorable rock mass elastic modulus measured in situ, and a quasi-static internal water pressure. Such a conventional model is thus axisymmetrical and has an analytical solution for stresses and displacements. However, rock masses often have an anisotropic behavior and such isotropic assumption is usually conservative in terms of quasi-static maximum stresses in the steel liner. In this work, the stresses and displacements in steel-lined pressure tunnels and shafts in anisotropic rock mass are studied by means of the finite element method. A quasi-static internal water pressure is considered. The materials are considered linear elastic, and tied contact is assumed between the layers. The constitutive models used for the rock mass and the cracked layers are presented and the practical ranges of variation of the parameters are discussed. An extensive systematic parametric study is performed and stresses and displacements in the steel liner and in the far-field rock mass are presented. Finally, correction factors are derived to be included in the axisymmetrical solution which allow a rapid estimate of the maximum stresses in the steel liners of pressure tunnels and shafts in anisotropic rock.

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

    NASA Technical Reports Server (NTRS)

    Kranz, R. L.

    1979-01-01

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

  1. Local distribution of wall static pressure and heat transfer on a smooth flat plate impinged by a slot air jet

    NASA Astrophysics Data System (ADS)

    M, Adimurthy; Katti, Vadiraj V.

    2017-02-01

    Local distribution of wall static pressure and heat transfer on a smooth flat plate impinged by a normal slot air jet is experimental investigated. Present study focuses on the influence of jet-to-plate spacing ( Z/D h ) (0.5-10) and Reynolds number (2500-20,000) on the fluid flow and heat transfer distribution. A single slot jet with an aspect ratio ( l/b) of about 22 is chosen for the current study. Infrared Thermal Imaging technique is used to capture the temperature data on the target surface. Local heat transfer coefficients are estimated from the thermal images using `SMART VIEW' software. Wall static pressure measurement is carried out for the specified range of Re and Z/D h . Wall static pressure coefficients are seen to be independent of Re in the range between 5000 and 15,000 for a given Z/D h . Nu values are higher at the stagnation point for all Z/D h and Re investigated. For lower Z/D h and higher Re, secondary peaks are observed in the heat transfer distributions. This may be attributed to fluid translating from laminar to turbulent flow on the target plate. Heat transfer characteristics are explained based on the simplified flow assumptions and the pressure data obtained using Differential pressure transducer and static pressure probe. Semi-empirical correlation for the Nusselt number in the stagnation region is proposed.

  2. Local distribution of wall static pressure and heat transfer on a smooth flat plate impinged by a slot air jet

    NASA Astrophysics Data System (ADS)

    Adimurthy, M.; Katti, Vadiraj V.

    2016-06-01

    Local distribution of wall static pressure and heat transfer on a smooth flat plate impinged by a normal slot air jet is experimental investigated. Present study focuses on the influence of jet-to-plate spacing (Z/D h ) (0.5-10) and Reynolds number (2500-20,000) on the fluid flow and heat transfer distribution. A single slot jet with an aspect ratio (l/b) of about 22 is chosen for the current study. Infrared Thermal Imaging technique is used to capture the temperature data on the target surface. Local heat transfer coefficients are estimated from the thermal images using `SMART VIEW' software. Wall static pressure measurement is carried out for the specified range of Re and Z/D h . Wall static pressure coefficients are seen to be independent of Re in the range between 5000 and 15,000 for a given Z/D h . Nu values are higher at the stagnation point for all Z/D h and Re investigated. For lower Z/D h and higher Re, secondary peaks are observed in the heat transfer distributions. This may be attributed to fluid translating from laminar to turbulent flow on the target plate. Heat transfer characteristics are explained based on the simplified flow assumptions and the pressure data obtained using Differential pressure transducer and static pressure probe. Semi-empirical correlation for the Nusselt number in the stagnation region is proposed.

  3. Comparison of dynamic (brush) and static (pressure) mechanical allodynia in migraine.

    PubMed

    LoPinto, C; Young, W B; Ashkenazi, A

    2006-07-01

    Allodynia has been described in migraine but has not been fully investigated for the different sensory modalities. The aim of this study was to compare the prevalence of dynamic (brush) and static (pressure) mechanical allodynia in migraine patients and to suggest a practical method of testing them in a clinical setting. Patients with International Headache Society-defined episodic migraine (EM) or with transformed migraine (TM) as defined by Silberstein and Lipton were prospectively recruited from the Jefferson Headache Center out-patient clinic. A questionnaire of migraine features and symptoms of allodynia was administered. Brush allodynia (BA) was tested by cutaneous stimulation with a gauze pad and pressure allodynia (PA) was tested using von Frey hairs (VFH). The prevalence of BA and PA in all patients and in the different subgroups was calculated and correlated with migraine features. We recruited 55 migraine patients. Twenty-five had EM and 30 had TM. BA was present in 18 (32.7%) patients and PA in 18-24 (32.7-43.6%). Allodynia to both brush and pressure was found in 13-17 (23.6-30.9%) patients. If a patient had allodynia to one modality only, it was more likely to be PA than BA. Both BA and PA were more common in patients with TM compared with those with EM [BA 46.7% vs. 16.0%; PA (differences significant for the medium and thick VFHs) 50% vs. 20% and 50% vs. 12%, respectively]. Both types of allodynia were also more common in patients with migraine with aura compared with those with migraine without aura (BA 57.1% vs. 17.6%; PA 57.1-61.9% vs. 17.6-32.7%). There was a positive correlation between allodynia score (as obtained by examination) and allodynia index (as obtained by history) for both BA and PA. The incomplete, although considerable, overlap between BA and PA suggests that allodynia to different sensory modalities is associated with sensitization of different neuronal populations. Because PA was more common than BA, it may be a more sensitive

  4. Local distribution of wall static pressure and heat transfer on a rough flat plate impinged by a slot air jet

    NASA Astrophysics Data System (ADS)

    Meda, Adimurthy; Katti, Vadiraj V.

    2017-02-01

    The present work experimentally investigates the local distribution of wall static pressure and the heat transfer coefficient on a rough flat plate impinged by a slot air jet. The experimental parameters include, nozzle-to-plate spacing (Z/D h = 0.5-10.0), axial distance from stagnation point (x/D h ), size of detached rib (b = 4-12 mm) and Reynolds number (Re = 2500-20,000). The wall static pressure on the surface is recorded using a Pitot tube and a differential pressure transmitter. Infrared thermal imaging technique is used to capture the temperature distribution on the target surface. It is observed that, the maximum wall static pressure occurs at the stagnation point (x/D h = 0) for all nozzle-to-plate spacing (Z/D h ) and rib dimensions studied. Coefficient of wall static pressure (C p ) decreases monotonically with x/D h . Sub atmospheric pressure is evident in the detached rib configurations for jet to plate spacing up to 6.0 for all ribs studied. Sub atmospheric region is stronger at Z/D h = 0.5 due to the fluid accelerating under the rib. As nozzle to plate spacing (Z/D h ) increases, the sub-atmospheric region becomes weak and vanishes gradually. Reasonable enhancement in both C p as well as Nu is observed for the detached rib configuration. Enhancement is found to decrease with the increase in the rib width. The results of the study can be used in optimizing the cooling system design.

  5. 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.

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

    NASA Technical Reports Server (NTRS)

    Kranz, R. L.

    1980-01-01

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

  7. New data for aerosols generated by releases of pressurized powders and solutions in static air

    SciTech Connect

    Ballinger, M.Y.; Sutter, S.L.; Hodgson, W.H.

    1987-05-01

    Safety assessments and environmental impact statements for nuclear fuel cycle facilities require an estimate of potential airborne releases. Aerosols generated by accidents are being investigated by Pacific Northwest Laboratory to develop radioactive source-term estimation methods. Experiments measuring the mass airborne and particle size distribution of aerosols produced by pressurized releases were run. Carbon dioxide was used to pressurize uranine solutions to 50, 250, and 500 psig before release. The mass airborne from these experiments was higher than for comparable air-pressurized systems, but not as great as expected based on the amount of gas dissolved in the liquid and the volume of liquid ejected from the release equipment. Flashing sprays of uranine at 60, 125, and 240 psig produced a much larger source term than all other pressurized releases performed under this program. Low-pressure releases of depleted uranium dioxide at 9, 17.5, and 24.5 psig provided data in the energy region between 3-m spills and 50-psig pressurized releases.

  8. Peer Pressure

    MedlinePlus

    ... Surgery? A Week of Healthy Breakfasts Shyness Peer Pressure KidsHealth > For Teens > Peer Pressure A A A ... for the school play. previous continue When the Pressure's On Sometimes, though, the stresses in your life ...

  9. Blood pressure

    MedlinePlus Videos and Cool Tools

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

  10. 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.

  11. A New Method for Determining Material Thermal Properties at Static High Pressures

    NASA Astrophysics Data System (ADS)

    Carney, J. R.; Ladouceur, H. D.; Russell, T. P.; Pangilinan, G. I.

    2004-07-01

    The response of materials under shock loading is strongly dependent on the mechanical and thermal properties of materials at high pressures. Despite the availability of several methods that quantify mechanical properties of materials at high pressures and loading rates, only a few existing techniques can measure heat capacity or thermal conductivity at high pressures. A new method is proposed to determine the thermal transport properties of materials in gem anvil cells (GAC). The test material and a ruby sphere were enclosed in a GAC and brought to pressure. The ruby was heated at a constant rate by a pulse of light whose intensity had a square wave temporal profile. Time-resolved ruby fluorescence spectra were recorded with a spectrometer and a streak camera. The temperature profile of the ruby during both the heating and cooling (following removal of the laser light) periods was sensitively dependent on the thermal transport properties of the surrounding material. A pressure-dependent set of results is presented for sodium chloride (NaCl) and Teflon, utilizing this new technique. The data is compared to simulations using previously published data.

  12. Structural phase stability in group IV metals under static high pressure

    SciTech Connect

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

    2009-01-01

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

  13. Effect of static pressure on absolute paleointensity recording with implications for meteorites

    NASA Astrophysics Data System (ADS)

    Volk, Michael W. R.; Gilder, Stuart A.

    2016-08-01

    We investigated the influence of hydrostatic and nonhydrostatic stress on the recording process of magnetic field intensity with particular relevance for meteorites that experienced pressures lower than 5 GPa corresponding to the lowest shock stage classification (S1) in meteorites. Thermal remanent magnetizations were imparted on natural obsidian samples containing pseudo-single domain titanomagnetite, analogous to some achondritic meteorites. Thellier-type paleointensity experiments were carried out at ambient conditions after pressure cycling to 0.6, 1.2, and 1.8 GPa. Each experiment used 10 samples to assess reproducibility, which is better than ±5%. The recorded paleointensity decreased 10%/GPa under hydrostatic stress and 20%/GPa under nonhydrostatic stress, leading to the fundamental conclusion that paleointensity results from meteorites may be appreciably underestimated. Pressure cycling shifts the blocking and unblocking spectra, thereby producing more linear slopes on an Arai diagram with increasing strain. We explain why, for samples with a single magnetization component that does not alter, a two-step paleointensity protocol sufficiently resolves the true paleointensity. Moreover, we propose that pressure cycling of pseudo-single domain bearing samples will remove the inherent curvature of the Arai slope, thereby allowing one to obtain a more accurate estimate of the true paleointensity. This likely also holds true for samples possessing multidomain grains. Conversely, linear trends on Arai plots in meteorites might have their origin in a pressure effect that does not necessarily reflect the ubiquitous presence of single domain particles.

  14. Human Verification Using a Combination of Static and Dynamic Characteristics in Foot Pressure Images

    PubMed Central

    Zare, Fereshteh E.; Maghooli, Keivan

    2016-01-01

    Since gait is the mixture of many complex movements, each individual can define with a unique foot pressure image that can be used as a reliable biometric scale for human verification. Foot pressure color images of Center for Biometrics and Security Research (CBSR) dataset from 45 men and 5 women were used in this study. Owing to the properties of this dataset, an index of foot pressure in addition to external feature and contourlet coefficient of images was extracted. A multilayer perceptron (MLP) was utilized for verification of subjects (it is a common practice to explain more about the training and test dataset). To validate the algorithm performance, results were obtained using a 5-fold cross validation approach. The results indicated accuracy of 99.14±0.65 and equal error rate (EER) of 0.02. These results demonstrated the reliability of proposed neural network in human verification application. Hence, it can be utilized in other verification systems. PMID:28028498

  15. 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; Xia, Cheng-lai; Li, Jun-mu; Xiong, Yan; Yuan, Hao-yu; TANG, Zhen-Wang; Zeng, Yixin; Liao, Duan-fang

    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

  16. Dynamic and static effects of pressure: Spin transition kinetics and zero-field splitting

    NASA Astrophysics Data System (ADS)

    Wang, Wei

    1998-10-01

    The first chapter of this thesis is on the spin relaxation kinetics of Fe(II) coordination compounds in crystals under applied external pressure. The ligand- field strength of these complexes is such that the high- spin 5T 2g state is close in energy but above the low-spin 1A 1g state. The high- spin to low-spin relaxation process in these compounds deviates from Arrhenius behavior at low temperatures and is associated with a large change of the Fe-ligand bond length. The relaxation can be treated as a nuclear tunneling process along the Fe-ligand totally symmetric stretching normal coordinate. The tunneling rates of three octahedral Fe(II) complexes doped in their Zn and Mn analogs are measured as a function of pressure. A large increase of the tunneling rates with pressure was observed, including a nine orders of magnitude increase over 27 kbar for (Fe(mepy)3tren) (PF6)2. The key to the acceleration of the rates is the shift of the relative position of the potential energy surfaces under pressure. The data are well described with a rate law derived from Fermi's Golden Rule and modified by the Gruneisen approximation. In the second chapter addresses the effect of pressure on the pressure on the zero-field splitting of monocyclic aromatic diazines. The zero-field splitting parameters D and E of the lowest triplet states of pyrimidine, pyrazine, and s-tetramethylpyrazine in various hosts are measured as a function of pressure using the optically- detected magnetic resonance technique. The value of D decreases with pressure for most of the systems, with the largest decrease for s-tetramethylpyrazine, The value of E either increases or is fairly constant. For pyrimidine in benzene system, the parameters changed abruptly due to a phase transition of benzene at 14 kbar. The results for these systems are compared with the results of another aza-aromatic molecule, quinoxaline, and a system exhibiting vibronic coupling, p-benzoquinone. The data are explained in terms of

  17. 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.

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

    SciTech Connect

    Kumar, Ravhi S.; Dandekar, Dattatraya; Leithe-Jasper, Andres; Tanaka, Takaho; Xiao, Yuming; Chow, Paul; Nicol, Malcolm F.; Cornelius, Andrew L.

    2010-05-04

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

  19. 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.

  20. Global surface pressure measurements of static and dynamic stall on a wind turbine airfoil at low Reynolds number

    NASA Astrophysics Data System (ADS)

    Disotell, Kevin J.; Nikoueeyan, Pourya; Naughton, Jonathan W.; Gregory, James W.

    2016-05-01

    Recognizing the need for global surface measurement techniques to characterize the time-varying, three-dimensional loading encountered on rotating wind turbine blades, fast-responding pressure-sensitive paint (PSP) has been evaluated for resolving unsteady aerodynamic effects in incompressible flow. Results of a study aimed at demonstrating the laser-based, single-shot PSP technique on a low Reynolds number wind turbine airfoil in static and dynamic stall are reported. PSP was applied to the suction side of a Delft DU97-W-300 airfoil (maximum thickness-to-chord ratio of 30 %) at a chord Reynolds number of 225,000 in the University of Wyoming open-return wind tunnel. Static and dynamic stall behaviors are presented using instantaneous and phase-averaged global pressure maps. In particular, a three-dimensional pressure topology driven by a stall cell pattern is detected near the maximum lift condition on the steady airfoil. Trends in the PSP-measured pressure topology on the steady airfoil were confirmed using surface oil visualization. The dynamic stall case was characterized by a sinusoidal pitching motion with mean angle of 15.7°, amplitude of 11.2°, and reduced frequency of 0.106 based on semichord. PSP images were acquired at selected phase positions, capturing the breakdown of nominally two-dimensional flow near lift stall, development of post-stall suction near the trailing edge, and a highly three-dimensional topology as the flow reattaches. Structural patterns in the surface pressure topologies are considered from the analysis of the individual PSP snapshots, enabled by a laser-based excitation system that achieves sufficient signal-to-noise ratio in the single-shot images. The PSP results are found to be in general agreement with observations about the steady and unsteady stall characteristics expected for the airfoil.

  1. High pressure stability of protein complexes studied by static and dynamic light scattering

    NASA Astrophysics Data System (ADS)

    Gebhardt, Ronald; Kulozik, Ulrich

    2011-03-01

    The high pressure dissociation of hemocyanin prepared from the lobster Homarus americanus and casein micelles from cow milk were observed by in situ light scattering. The hemocyanin dodecamer dissociated via a hexamer into monomers in a two-step three-species reaction. The influence of ligands and the effector l-lactate on the dissociation behavior was investigated. While no effect by carbon monoxide after exchanging the ligand oxygen was observed, the addition of the effector l-lactate led to a decrease in the pressure stability. Due to a trimer intermediate which was found to be stabilized by l-lactate, the dissociation reaction in the presence of the effector was analyzed by a three-step four-species reaction. In the case of casein micelles, a two-step dissociation mechanism was found. The stabilizing interactions of casein micelles were identified and separated.

  2. 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.

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

    NASA Astrophysics Data System (ADS)

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

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

  4. Pressure Sores

    MedlinePlus

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

  5. 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.

  6. On the Growth of Steam Droplets Formed in a Laval Nozzle Using both Static Pressure and Light Scattering Measurements

    DTIC Science & Technology

    1977-01-01

    distribution f(r), the cross section Is m + 2 o and Is related to the measured light Intensities and scattering geometry by (da/dn)v- N (Y" 1) (f2) J...l)-(4) plus the static pressure data. In order to relate heat release to mass fraction con- densed the usual relation dq - Ldg is employed...versions have been applied to the themodynamic conditions of the conden- sation zone of Experiment 252. At onset the vapor concentration is the

  7. Barometric pressure

    NASA Technical Reports Server (NTRS)

    Billings, C. E.

    1973-01-01

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

  8. 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.

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

    SciTech Connect

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

    1999-12-01

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

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

    PubMed Central

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

    2014-01-01

    Object In the search for optimal monitoring and predictive tools in neurocritical care, the relationship of the pulsatile component of intracranial pressure (ICP) and the pressure itself has long been of great interest. Higher pressure often correlates with a higher pulsatile response to the heartbeat, interpreted as a type of compliance curve. Various mathematical approaches have been used, but regardless of the formula used, it is implicitly assumed that a reproducible curve exists. The authors investigated the stability of the correlation between static and pulsatile ICPs in patients with subarachnoid hemorrhage (SAH) who were observed for several hours by using data sets large enough to allow such calculations to be made. Methods The ICP recordings were obtained in 39 patients with SAH and were parsed into 6-second time windows (1,998,944 windows in 197 recordings). The ICP parameters were computed for each window as follows: static ICP was defined as the mean ICP, and pulsatile ICP was characterized by mean ICP wave amplitude, rise time, and rise time coefficient. Results The mean ICP and ICP wave amplitudes were simultaneously high or low (the expected correlation) in only ~ 60% of observations. Furthermore, static and pulsatile ICP correlated well only over short intervals; the degree of correlation weakened over periods of hours and was inconsistent across patients and within individual patients over time. Decorrelation originated with abrupt shifting and gradual drifting of mean ICP and ICP wave amplitude over several hours. Conclusions The relationship between the static and pulsatile components of ICPs changes over time. It evolves, even in individual patients, over a number of hours. This can be one reason the observation of high pulsatile ICP (indicative of reduced intracranial compliance) despite normal mean ICP that is seen in some patients with SAH. The meaning and potential clinical usefulness of such changes in the curves is uncertain, but it

  11. Pressure gauge

    SciTech Connect

    Morita, S.

    1985-04-02

    A pressure receiving element for receiving an external pressure is attached to one end of a body and a temperature compensating diaphragm is attached to the other end of the body. A coupling shaft disposed in the body is fixed at both ends to the pressure receiving element and the diaphragm, respectively. A liquid is sealed in the body and means is provided for detecting displacement or force applied to the coupling shaft in accordance with a pressure received by the pressure receiving element. The diaphragm has corrugations of concentric circles and the crests of a plurality of them are made flat and one of the flat crests is fixed to the body. The effective area of the diaphragm inside of the flat crest that is fixed to the body is selected substantially to be equal to the effective area of the pressure receiving element.

  12. Non-invasive estimation of static and pulsatile intracranial pressure from transcranial acoustic signals.

    PubMed

    Levinsky, Alexandra; Papyan, Surik; Weinberg, Guy; Stadheim, Trond; Eide, Per Kristian

    2016-05-01

    The aim of the present study was to examine whether a method for estimation of non-invasive ICP (nICP) from transcranial acoustic (TCA) signals mixed with head-generated sounds estimate the static and pulsatile invasive ICP (iICP). For that purpose, simultaneous iICP and mixed TCA signals were obtained from patients undergoing continuous iICP monitoring as part of clinical management. The ear probe placed in the right outer ear channel sent a TCA signal with fixed frequency (621 Hz) that was picked up by the left ear probe along with acoustic signals generated by the intracranial compartment. Based on a mathematical model of the association between mixed TCA and iICP, the static and pulsatile nICP values were determined. Total 39 patients were included in the study; the total number of observations for prediction of static and pulsatile iICP were 5789 and 6791, respectively. The results demonstrated a good agreement between iICP/nICP observations, with mean difference of 0.39 mmHg and 0.53 mmHg for static and pulsatile ICP, respectively. In summary, in this cohort of patients, mixed TCA signals estimated the static and pulsatile iICP with rather good accuracy. Further studies are required to validate whether mixed TCA signals may become useful for measurement of nICP.

  13. 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.

  14. Wetting and spreading of nanofluids on solid surfaces driven by the structural disjoining pressure: statics analysis and experiments.

    PubMed

    Kondiparty, Kirti; Nikolov, Alex; Wu, Stanley; Wasan, Darsh

    2011-04-05

    The wetting and spreading of nanofluids composed of liquid suspensions of nanoparticles have significant technological applications. Recent studies have revealed that, compared to the spreading of base liquids without nanoparticles, the spreading of wetting nanofluids on solid surfaces is enhanced by the structural disjoining pressure. Here, we present our experimental observations and the results of the statics analysis based on the augmented Laplace equation (which takes into account the contribution of the structural disjoining pressure) on the effects of the nanoparticle concentration, nanoparticle size, contact angle, and drop size (i.e., the capillary and hydrostatic pressure); we examined the effects on the displacement of the drop-meniscus profile and spontaneous spreading of a nanofluid as a film on a solid surface. Our analyses indicate that a suitable combination of the nanoparticle concentration, nanoparticle size, contact angle, and capillary pressure can result not only in the displacement of the three-phase contact line but also in the spontaneous spreading of the nanofluid as a film on a solid surface. We show here, for the first time, that the complete wetting and spontaneous spreading of the nanofluid as a film driven by the structural disjoining pressure gradient (arising due to the nanoparticle ordering in the confined wedge film) is possible by decreasing the nanoparticle size and the interfacial tension, even at a nonzero equilibrium contact angle. Experiments were conducted on the spreading of a nanofluid composed of 5, 10, 12.5, and 20 vol % silica suspensions of 20 nm (geometric diameter) particles. A drop of canola oil was placed underneath the glass surface surrounded by the nanofluid, and the spreading of the nanofluid was monitored using an advanced optical technique. The effect of an electrolyte, such as sodium chloride, on the nanofluid spreading phenomena was also explored. On the basis of the experimental results, we can conclude

  15. The Effect of Work Boots on Knee Mechanics and the Center of Pressure at the Knee During Static Kneeling.

    PubMed

    Tennant, Liana; Kingston, David; Chong, Helen; Acker, Stacey

    2015-10-01

    Occupational kneeling is associated with an increased risk for the development of knee osteoarthritis. Previous work studying occupational kneeling has neglected to account for the fact that in many industrial settings, workers are required to wear steel-toe work boots. Thus, the purpose of this study was to evaluate the effect of work boot wear on the center of pressure location of the ground reaction force, knee joint angle, and magnitude of the ground reaction force in a kneeling posture. Fifteen healthy males were fit with 3D motion capture markers and knelt statically over a force plate embedded in the floor. Using the tibial tuberosity as the point of reference, the center of pressure in shod condition was shifted significantly medially (on average 0.009 m [P = .005]) compared with the barefoot condition. The knee was significantly less internally rotated (shod: -12.5° vs. barefoot: -17.4° [P = .009]) and the anterior/posterior shear force was significantly greater in the shod condition (shod: 6.0% body weight vs. barefoot: 1.5% body weight [P = .002]). Therefore, wearing work boots alters the kneeling posture compared with barefoot kneeling, potentially loading different surfaces of the knee, as well as altering knee joint moments.

  16. Pressure Drop

    NASA Technical Reports Server (NTRS)

    Lawson, Mike

    2010-01-01

    Mike Lawson briefly discussed pressure drop for aerospace applications and presented short stories about adventures experienced while working at NASA and General Dynamics, including exposure to technologies like the Crew and Equipment Translation Aid (CETA) cart and the SWME.

  17. Pressure sensor

    DOEpatents

    Mee, David K.; Ripley, Edward B.; Nienstedt, Zachary C.; Nienstedt, Alex W.; Howell, Jr., Layton N.

    2015-09-29

    Disclosed is a passive, in-situ pressure sensor. The sensor includes a sensing element having a ferromagnetic metal and a tension inducing mechanism coupled to the ferromagnetic metal. The tension inducing mechanism is operable to change a tensile stress upon the ferromagnetic metal based on a change in pressure in the sensing element. Changes in pressure are detected based on changes in the magnetic switching characteristics of the ferromagnetic metal when subjected to an alternating magnetic field caused by the change in the tensile stress. The sensing element is embeddable in a closed system for detecting pressure changes without the need for any penetrations of the system for power or data acquisition by detecting changes in the magnetic switching characteristics of the ferromagnetic metal caused by the tensile stress.

  18. Pressure regulator

    DOEpatents

    Ebeling, Jr., Robert W.; Weaver, Robert B.

    1979-01-01

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

  19. PRESSURE TRANSDUCER

    DOEpatents

    Sander, H.H.

    1959-10-01

    A pressure or mechanical force transducer particularly adaptable to miniature telemetering systems is described. Basically the device consists of a transistor located within a magnetic field adapted to change in response to mechanical force. The conduction characteristics of the transistor in turn vary proportionally with changes in the magnetic flux across the transistor such that the output (either frequency of amplitude) of the transistor circuit is proportional to mechanical force or pressure.

  20. Static and Wind-on Performance of Polymer-Based Pressure-Sensitive Paints Using Platinum and Ruthenium as the Luminophore.

    PubMed

    Lo, Kin Hing; Kontis, Konstantinos

    2016-04-26

    An experimental study has been conducted to investigate the static and wind-on performance of two in-house-developed polymer-based pressure-sensitive paints. Platinum tetrakis (pentafluorophenyl) porphyrin and tris-bathophenanthroline ruthenium II are used as the luminophores of these two polymer-based pressure-sensitive paints. The pressure and temperature sensitivity and the photo-degradation rate of these two pressure-sensitive paints have been investigated. In the wind tunnel test, it was observed that the normalised intensity ratio of both polymer-based pressure-sensitive paints being studied decreases with increasing the number of wind tunnel runs. The exact reason that leads to the occurrence of this phenomenon is unclear, but it is deduced that the luminophore is either removed or deactivated by the incoming flow during a wind tunnel test.

  1. Static and Wind-on Performance of Polymer-Based Pressure-Sensitive Paints Using Platinum and Ruthenium as the Luminophore

    PubMed Central

    Lo, Kin Hing; Kontis, Konstantinos

    2016-01-01

    An experimental study has been conducted to investigate the static and wind-on performance of two in-house-developed polymer-based pressure-sensitive paints. Platinum tetrakis (pentafluorophenyl) porphyrin and tris-bathophenanthroline ruthenium II are used as the luminophores of these two polymer-based pressure-sensitive paints. The pressure and temperature sensitivity and the photo-degradation rate of these two pressure-sensitive paints have been investigated. In the wind tunnel test, it was observed that the normalised intensity ratio of both polymer-based pressure-sensitive paints being studied decreases with increasing the number of wind tunnel runs. The exact reason that leads to the occurrence of this phenomenon is unclear, but it is deduced that the luminophore is either removed or deactivated by the incoming flow during a wind tunnel test. PMID:27128913

  2. Static ultra-high pressure study of lanthanide and actinide metals using a diamond-anvil cell

    SciTech Connect

    Akella, J.; Smith, G.S.; Weir, S.T.

    1993-06-30

    Structural phase transformation in lanthanides and actinides were investigated as a function of pressure up to 300 GPa at room temperature. Except in Ce and Pr, no large volume changes were noticed for these metals as thy went through several phase changes. The appearance of a bct ultra-high pressure phase in Ce, Sm, Th, and possibly in Np, raises the possibility that the ultimate high pressure structure for the 4f and 5f metals may be the bct structure. On the other hand, it is also possible that this is a precursor to another close-packed structure at even higher pressure.

  3. High Blood Pressure

    MedlinePlus

    ... this page please turn Javascript on. High Blood Pressure What Is High Blood Pressure? High blood pressure is a common disease in ... at higher than normal pressures. What Is Blood Pressure? Click for more information Blood pressure is the ...

  4. Blood pressure measurement

    MedlinePlus

    ... reading; Measuring blood pressure; Hypertension - blood pressure measurement; High blood pressure - blood pressure measurement ... High blood pressure has no symptoms so you may not know if you have this problem. High blood pressure ...

  5. Fluid pressure balanced seal

    NASA Technical Reports Server (NTRS)

    Marsh, H. W. (Inventor)

    1966-01-01

    A seal which increases in effectiveness with increasing pressure is presented. The seal's functional capability throughout both static and dynamic operation makes it particularly useful for sealing ball valve ports. Other features of the seal include the ability to seal two opposed surfaces simultaneously, tolerance of small misalignments, tolerance of wide temperature ranges, ability to maintain positive sealing contact under conditions of internal or external pressurization, and ability to conform to slight irregularities in seal or surface contours.

  6. 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.

  7. The effects of plantar flexor static stretching and dynamic stretching using an aero-step on foot pressure during gait in healthy adults: a preliminary study.

    PubMed

    Shim, Je-Myung; Jung, Ju-Hyeon; Kim, Hwan-Hee

    2015-07-01

    [Purpose] The aim of this study was to examine whether plantar flexor static stretching and dynamic stretching using an Aero-Step results in changes in foot pressure during gait in healthy adults. [Subjects] Eighteen normal adults were randomly allocated to either a dynamic stretching using an Aero-Step group (DSUAS) group (n = 8) or a static stretching (SS) group (n = 10). [Methods] The DSUAS and SS participants took part in an exercise program for 15 minutes. Outcome measures were foot plantar pressure, which was measured during the subject's gait stance phase; the asymmetric ratio of foot pressure for both feet; and the visual analogue scale (VAS) measured during the interventions. [Results] There were significant differences in the asymmetric ratio of foot pressure for both feet and VAS between the two groups after intervention. However, there were no significant differences in foot plantar pressure during the gait stance phase within both groups. [Conclusion] DSUSAS is an effective stretching method, as pain during it is lower than that with SS, which can minimize the asymmetric ratio of foot pressure for both feet during gait due to asymmetric postural alignment.

  8. Abnormal pressures as hydrodynamic phenomena

    USGS Publications Warehouse

    Neuzil, C.E.

    1995-01-01

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

  9. Pressure Alopecia

    PubMed Central

    Davies, Kate E; Yesudian, PD

    2012-01-01

    Postoperative or pressure alopecia (PA) is an infrequently reported group of scarring and non-scarring alopecias. It has been reported after immobilization of the head during surgery and following prolonged stays on intensive care units, and may be analogous to a healed pressure ulcer. This review presents a summary of cases published in pediatrics and after cardiac, gynecological, abdominal and facial surgeries. PA may manifest as swelling, tenderness, and ulceration of the scalp in the first few postoperative days; in other cases, the alopecia may be the presenting feature with a history of scalp immobilization in the previous four weeks. The condition may cause considerable psychological distress in the long term. Regular head turning schedules and vigilance for the condition should be used as prophylaxis to prevent permanent alopecia. A multi-center study in high-risk patients would be beneficial to shed further light on the etiology of the condition. PMID:23180911

  10. Cooperative coupling of static magnetism and bulk superconductivity in the stripe phase of La2 -xBaxCuO4 : Pressure- and doping-dependent studies

    NASA Astrophysics Data System (ADS)

    Guguchia, Z.; Khasanov, R.; Shengelaya, A.; Pomjakushina, E.; Billinge, S. J. L.; Amato, A.; Morenzoni, E.; Keller, H.

    2016-12-01

    Static spin-stripe order and superconductivity were systematically studied in La2 -xBaxCuO4 (0.11 ≤x ≤0.17 ) at ambient pressure by means of magnetization and μ SR experiments. We find that all the investigated La2 -xBaxCuO4 samples exhibit static spin-stripe order and that the quasi-two-dimensional superconducting (SC) transition temperature Tc 1 and the static spin-stripe order temperature Tso have very similar values throughout the phase diagram. Moreover, the magnetic and the SC properties of the x =0.155 (LBCO-0.155) and x =0.17 (LBCO-0.17) samples were studied under hydrostatic pressure. As a remarkable result, in these bulk cuprate superconductors, the three-dimensional SC transition temperature Tc and Tso nearly coincide [Tc(p ) ≃Tso(p ) ] at all pressure investigated (0 ≤p ≤2.3 GPa). We also observed a pressure induced transition from long-range spin stripe order to a disordered magnetic state at p≃1.6 GPa in LBCO-0.155, coexisting with a SC state with substantial superfluid density. In LBCO-0.17, a disordered magnetic state is present at all p . The present results indicate that static magnetic order and SC pairing correlations develop in a cooperative fashion in La2 -xBaxCuO4 , and provide a new route of understanding the complex interplay between static magnetism and superconductivity in the stripe phase of cuprates.

  11. Pressure transducer

    DOEpatents

    Anderson, Thomas T.; Roop, Conard J.; Schmidt, Kenneth J.; Gunchin, Elmer R.

    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.

  12. 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.

  13. 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)

  14. Differences in the body pressure-related sensory changes between the floor and mattress in a static supine position for physiotherapy research: a randomized controlled pilot trial

    PubMed Central

    Lee, Won-Deok; Lee, Jeong-Uk; Kim, Mee-Young; Lee, Lim-Kyu; Park, Byoung-Sun; Yang, Seung-Min; Noh, Ji-Woong; Shin, Yong-Sub; Kim, Ju-Hyun; Kwak, Taek-Yong; Lee, Tae-Hyun; Park, Jaehong; Kim, Junghwan

    2016-01-01

    [Purpose] This study was performed to investigate the difference in body pressure–related sensory changes between the floor and mattress in a static supine position for physiotherapy research. [Subjects and Methods] To analyze body pressure, the Body Pressure Measurement System was used. Body pressure sensors were attached to mattresses and the floor beneath the subjects. The level of pain was evaluated using pain score tools before the static supine position was adopted, at 1, 5, 10, and 15 min, and in total for specific body points. [Results] In analysis of digitized images, there was no significant difference observed between floor and mattress body pressure values at the start position. However, the head pressure intensity was significantly higher than that of the other body parts. In analysis of pain scores, all body part pain scores except those for both legs were significantly higher for the floor than for the mattress. Furthermore, the pain scores of the floor group were significantly increased at minute 1 compared with those of the mattress group. [Conclusion] These results suggest that properties that change in a time-dependent manner and postural changes need to be carefully considered when applying physical therapy. PMID:27190432

  15. Gradual Rewarming with Gradual Increase in Pressure during Machine Perfusion after Cold Static Preservation Reduces Kidney Ischemia Reperfusion Injury

    PubMed Central

    Mahboub, Paria; Ottens, Petra; Seelen, Marc; t Hart, Nails; Van Goor, Harry; Ploeg, Rutger; Martins, Paulo; Leuvenink, Henri

    2015-01-01

    In this study we evaluated whether gradual rewarming after the period of cold ischemia would improve organ quality in an Isolated Perfused Kidney Model. Left rat kidneys were statically cold stored in University of Wisconsin solution for 24 hours at 4°C. After cold storage kidneys were rewarmed in one of three ways: perfusion at body temperature (38°C), or rewarmed gradually from 10°C to 38°C with stabilization at 10°C for 30 min and rewarmed gradually from 10°C to 38°C with stabilization at 25°C for 30 min. In the gradual rewarming groups the pressure was increased stepwise to 40 mmHg at 10°C and 70 mmHg at 25°C to counteract for vasodilatation leading to low perfusate flows. Renal function parameters and injury biomarkers were measured in perfusate and urine samples. Increases in injury biomarkers such as aspartate transaminase and lactate dehydrogenase in the perfusate were lower in the gradual rewarming groups versus the control group. Sodium re-absorption was improved in the gradual rewarming groups and reached significance in the 25°C group after ninety minutes of perfusion. HSP-70, ICAM-1, VCAM-1 mRNA expressions were decreased in the 10°C and 25°C groups. Based on the data kidneys that underwent gradual rewarming suffered less renal parenchymal, tubular injury and showed better endothelial preservation. Renal function improved in the gradual rewarming groups versus the control group. PMID:26630031

  16. [Indices of static and dynamic components of pressure load (assessed by 24-hour blood pressure monitoring) and the state of renal function in patients with essential hypertension].

    PubMed

    Zelveian, P A; Buniatian, M S; Oshchepkova, E V; Lazareva, N V; Rogoza, A N

    2011-01-01

    Aim of this study was to evaluate possible relationship between parameters of blood pressure (BP) profile and glomerular filtration rate in patients (pts) with I-II stage essential hypertension (EH). Material and methods. We studied 120 pts (97 men), aged 23-65 (50,2+/-0,6) years with I (n=98) and II (n=22) stage EH. In BP profile (SL-90207) we calculated 24-hour, daytime, nighttime values of systolic, diastolic, pulse pressures (SBP, DBP, PP), time load (TL), variability and nocturnal fall (NF) of BP. The state of renal function was assessed by measurement of glomerular filtration rate (GFR) calculated by the Cockcroft formula. Results. After nonlinear statistical analysis by Gauss-Newton all patients were divided into three groups according to GFR tertiles. Significant differences were found between these groups by 24-hour, nighttime and daytime values of SBP and DBP. Values of SBP were the lowest in group II. In group II lowest values of PP were also observed, but statistically significant differences were found only in nocturnal PP values between groups II and III. There were no significant differences between groups by TL and NF of BP. In group Ill (high GFR) variability of daytime values of SBP and DBF were significantly higher. Univariate correlation analysis showed statistically significant negative relationship between GFR and nocturnal PP in patients with lowest level of GFR. Positive correlations between nocturnal values of PP and GFR in groups II and III were also observed. Conclusion. These results indicated the presence of strong relationship between high values of nocturnal PP and decreasing of glomerular filtration rate in patients with EH and thus confirmed significance of "constant" and "dynamic" components of pressure load as a marker of impairment of renal function.

  17. High Blood Pressure

    MedlinePlus

    ... the NHLBI on Twitter. Description of High Blood Pressure Español High blood pressure is a common disease ... arteries) at higher than normal pressures. Measuring Blood Pressure Blood pressure is the force of blood pushing ...

  18. High-pressure/high-temperature gas-solubility study in hydrogen-phenanthrene and methane-phenanthrene systems using static and chromatographic techniques

    SciTech Connect

    Malone, P.V.

    1987-01-01

    The design and discovery of sources for alternative energy such as coal liquefaction has become of major importance over the past two decades. One of the major problems in such design in the lack of available data, particularly, for gas solubility in polycyclic aromatics at high temperature and pressure. Static and gas-liquid partition chromatographic methods were used for the study of hydrogen-phenanthrene and methane-phenanthrene systems. The static data for these two binaries were taken along 398.2, 423.2, 448.2, and 473.2 K isotherms up to 25.23 MPa. Gas-liquid partition chromatography was used to study the infinite dilution behavior of methane, ethane, propane, n-butane, and carbon dioxide in the hydrogen-phenanthrene system as well as hydrogen, ethane, n-butane, and carbon dioxide in the methane-phenanthrene binary. The principle objective was to examine the role of the elution gas. Temperatures were along the same isotherms as the static data and up to 20.77 MPa. With the exception of carbon dioxide, Henry's constants were calculated for all systems. Expressions for the heat of solution as a function of pressure were derived for both binary and chromatographic data. Estimates of delta H/sub i/sup sol/ at high pressure were presented.

  19. A comparison study of brachial blood pressure recorded with Spacelabs 90217A and Mobil-O-Graph NG devices under static and ambulatory conditions.

    PubMed

    Sarafidis, P A; Lazaridis, A A; Imprialos, K P; Georgianos, P I; Avranas, K A; Protogerou, A D; Doumas, M N; Athyros, V G; Karagiannis, A I

    2016-12-01

    Ambulatory blood pressure monitoring is an important tool in hypertension diagnosis and management. Although several ambulatory devices exist, comparative studies are scarce. This study aimed to compare for the first time brachial blood pressure levels of Spacelabs 90217A and Mobil-O-Graph NG, under static and ambulatory conditions. We examined 40 healthy individuals under static (study A) and ambulatory (study B) conditions. In study A, participants were randomized into two groups that included blood pressure measurements with mercury sphygmomanometer, Spacelabs and Mobil-O-Graph devices with reverse order of recordings. In study B, simultaneous 6-h recordings with both devices were performed with participants randomized in two sequences of device positioning with arm reversal at 3 h. Finally, all the participants filled in a questionnaire rating their overall preference for a device. In study A, brachial systolic blood pressure (117.2±10.3 vs 117.1±9.8 mm Hg, P=0.943) and diastolic blood pressure (73.3±9.4 mm Hg vs 74.1±9.4 mm Hg, P=0.611) did not differ between Spacelabs and Mobil-O-Graph or vs sphygmomanometer (117.8±11.1 mm Hg, P=0.791 vs Spacelabs, P=0.753 vs Mobil-O-Graph). Similarly, no differences were found in ambulatory systolic blood pressure (117.9±11.4 vs 118.3±11.0 mm Hg, P=0.864), diastolic blood pressure (73.7±7.4 vs 74.7±8.0 mm Hg, P=0.571), mean blood pressure and heart rate between Spacelabs and Mobil-O-Graph. Correlation analyses and Bland-Altman plots showed agreement between the monitors. Overall, the participants showed a preference for the Mobil-O-Graph. Spacelabs 90217A and Mobil-O-Graph NG provide practically identical measurements during the static and ambulatory conditions in healthy individuals and can be rather used interchangeably in clinical practice.

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

    NASA Technical Reports Server (NTRS)

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

    1974-01-01

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

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

    EPA Science Inventory

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

  2. 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,...

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

    SciTech Connect

    Vasco, D.W.

    2011-10-01

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

  4. Pressure-volume curves, static compliances and gas exchange in hyaline membrane disease during conventional mechanical and high-frequency ventilation.

    PubMed

    Pfenninger, J; Minder, C

    1988-01-01

    Eight premature infants with hyaline membrane disease needing artificial ventilation were studied at a mean age of 26.5 h. After a preparative phase they were randomly assigned either first to conventional mechanical ventilation (CMV; delivered by a Siemens Servo 900 C), followed by high-frequency ventilation (HFV; delivered by Percussionaire VDR 1 at 10 Hz) or vice versa, each period lasting 4 h. At the end of each period, arterial blood gases, lung volumes and alveolar pressures (Palv) during CMV or HFV and pressure-volume (P-V) curves of the total respiratory system were determined. Expiratory volumes were measured spirometrically, Palv by the clamping method, and the P-V curve was constructed by the syringe method. Single point static compliance at end-inspiration was higher during HFV (0.40 +/- 0.10 vs. 0.32 +/- 0.08 ml/cmH2O.kg-1; p = 0.02), whereas at end-expiration no difference was noted. Two points static compliances were also better during HFV than during CMV (0.32 +/- 0.08 vs. 0.24 +/- 0.06 ml/cmH2O.kg-1; p = 0.01). Static compliances derived from the steepest part of the inflation limb of the P-V curve were 0.55 +/- 0.12 after CMV and 0.50 +/- 0.12 ml/cmH2O.kg-1 after HFV (n.s.). Compared to CMV, HFV resulted in similar oxygenation and CO2-elimination at equal mean lung volumes, but at significantly lower mean Palv. It is concluded that recruitment of lung volume is achieved with less static recoil pressure by HFV. These findings are explained by differences in inspiration allowing more time for volume recruitment during HFV.

  5. Differential pressure pin discharge apparatus

    DOEpatents

    Oakley, David J.

    1987-01-01

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

  6. Differential pressure pin discharge apparatus

    DOEpatents

    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.

  7. Differential pressure pin discharge apparatus

    DOEpatents

    Oakley, David J.

    1987-02-03

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

  8. Low Blood Pressure

    MedlinePlus

    ... a problem. Sometimes blood pressure that is too low can also cause problems. Blood pressure is the ... reading is 90/60 or lower, you have low blood pressure. Some people have low blood pressure ...

  9. PRESSURE TRANSDUCER RESEARCH.

    DTIC Science & Technology

    PIEZOELECTRIC TRANSDUCERS, PRESSURE), UNDERGROUND EXPLOSIONS, ELECTRICAL RESISTANCE, SEEBECK EFFECT , PRESSURE GAGES, SHOCK WAVES, STRESSES, COMPUTER PROGRAMMING, NUCLEAR EXPLOSIONS, NUCLEAR RADIATION.

  10. Maximization of the working domain of an Atmospheric Pressure Townsend Discharge (APTD) using a current-source static converter

    NASA Astrophysics Data System (ADS)

    Bouzidi, M. C.; Bonnin, X.; Naudé, N.; Piquet, H.; Belinger, A.; Gherardi, N.

    2014-11-01

    The objective of this paper is to present the implementation of a square- wave current inverter power supply, and to describe its effect on the working domain of an Atmospheric Pressure Townsend Discharge (ATPD) in nitrogen. The results show that it allows a substantial increase of the percentage of time during which the discharge is ON (on-time) and therefore of the power delivered to the discharge, reaching almost 10 W/cm2 in pure nitrogen. Moreover, the increase of the on-time of the discharge implies a decrease of the extinction off-time between two discharges, and thus an increase of the memory effect from one discharge to the following one, as it is monitored by using electrical and optical measurements. This leads to a larger working domain of the ATPD, even when adding impurities in nitrogen.

  11. Effect of Ratio of Jet Area to Total Area and of Pressure Ratio on Lift Augmentation of Annular Jets in Ground Effect Under Static Conditions

    NASA Technical Reports Server (NTRS)

    Goodson, Kenneth W.; Otis, James H., Jr.

    1961-01-01

    The present investigation was undertaken to determine the effects of the ratio of jet area to total area and of the pressure ratio on the lift-augmentation characteristics of annular jets in ground effect. The investigation was made over an area-ratio range of 1.00 to 0.02 and a pressure-ratio range of about 1.04 to 1.95. Several configurations with center jets were tested through an angle-of-attack range to determine the pitching-moment characteristics. The tests were conducted in a static test room with the use of the compressed-air facilities. The results show that lift augmentation increases somewhat as the area ratio is reduced to about 0.10, below which it deteriorates due to thin jet mixing. The effect of pressure ratio on lift was negligible for the area-ratio range investigated. Calculations of the lift per air horsepower for a given base loading indicate that the greatest lift per air horsepower occurs at area ratios above 0.10, where the greatest lift augmentation occurs. The data show that annular-Jet vehicles are unstable at ratios of height above ground to nozzle diameter above about 0.10. The stability of the annular-jet vehicle can be improved by the use of large center jets. Base compartments also reduces the unstable moment.

  12. The static pressure field as a driving mechanism for the streamwise corner flow in the presence of an inclined transverse plane

    NASA Astrophysics Data System (ADS)

    Georgiou, Demos P.; Milidonis, Kypros F.

    2014-03-01

    Streamwise corner flows are characterized by the strong interaction among the boundary layers on the two walls that create the junction. The nature of this interaction defines some critical aspects of the corner flow, such as instability and laminar-turbulent transition, turbulence statistics and local shear friction and heat transfer intensities. The studies so far (both experimental and analytical) have investigated the configurations where the mainstream is mostly parallel to both walls. Under such conditions, the interaction is mainly viscous. Hence, a correct understanding of the flow dynamics requires a comprehensive knowledge of the velocity (mean and turbulent) field. In a number, however, of important applications (especially in turbomachinery blades and aircraft wing junctions), the mainstream flow is inclined against the blocking wall. This generates strong pressure gradients that modify significantly the structure of the relevant flowfield. The present study investigates experimentally the significance of the static pressure field associated with such geometries, focusing on the magnitudes and the directions along which the pressure pushes the flow. The results indicate that (1) the basic model explaining the flow interactions near a streamwise corner must be modified, and (2) the presence of an inclined wall modifies the relevant field significantly, by forcing a more intensive rotation on the mainstream, which leads to more intensive streamwise accelerations and wall jet effects near the corner.

  13. Dealing with Peer Pressure

    MedlinePlus

    ... Happens in the Operating Room? Dealing With Peer Pressure KidsHealth > For Kids > Dealing With Peer Pressure A ... talk about how to handle it. Defining Peer Pressure Peers influence your life, even if you don' ...

  14. Dealing with Peer Pressure

    MedlinePlus

    ... Video: Getting an X-ray Dealing With Peer Pressure KidsHealth > For Kids > Dealing With Peer Pressure Print ... talk about how to handle it. Defining Peer Pressure Peers influence your life, even if you don' ...

  15. Yield-pressure determination

    NASA Technical Reports Server (NTRS)

    Wakefield, M. E.

    1977-01-01

    Stress/strain relationship of complex-shape vessel is recorded under hydrostatic pressure. Technique is used to test pressurized gas cylinders and tubular transition joints made of dissimilar metals and to determine burst or system-failure pressures.

  16. Intracranial pressure monitoring

    MedlinePlus

    ... head. The monitor senses the pressure inside the skull and sends measurements to a recording device. ... are 3 ways to monitor pressure in the skull (intracranial pressure). INTRAVENTRICULAR CATHETER The intraventricular catheter is ...

  17. High blood pressure medicines

    MedlinePlus

    Hypertension - medicines ... blood vessel diseases. You may need to take medicines to lower your blood pressure if lifestyle changes ... blood pressure to the target level. WHEN ARE MEDICINES FOR HIGH BLOOD PRESSURE USED Most of the ...

  18. Effect of shoes with rounded soft soles in the anterior-posterior direction on the center of pressure during static standing.

    PubMed

    Demura, Tomohiro; Demura, Shin-ichi; Uchiyama, Masanobu; Kitabayashi, Tamotsu; Takahashi, Kenji

    2015-06-01

    Shoes with curved rocker bottom soles may induce an unstable standing posture. This study was aimed to mainly examine the effect of such shoes on the center of pressure (COP) during static standing. Ten healthy young male adults had their COP measured during static standing with four types of shoe conditions (Stretch Walker(®): SW (shoes with curved rocker bottom soles), Masai Barefoot Technology®: MBT (similar to SW in form and material), more conventionally soled shoes with a typical toe-spring: MCS, and bare feet: BF) for 60s. The mean path length and mean velocity of Y (front-back) axis were significantly greater when wearing the MBT than when wearing the SW, and when wearing the SW than when BF or when wearing the MCS. In addition, mean velocity of X (left-right) axis, area surrounding root mean square, root mean square, and root mean square of Y-axis were significantly greater when wearing the MBT than when wearing the SW, MCS, or when BF. In conclusion, when wearing the MBT or SW with rounded sole, static standing posture becomes unstable because of their characteristics as compared with wearing MCS or when BF, but the MBT has a larger sway in the front-back direction than the SW.

  19. 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.

  20. Neural Network Burst Pressure Prediction in Composite Overwrapped Pressure Vessels

    NASA Technical Reports Server (NTRS)

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

    2007-01-01

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

  1. Pressure-volume-temperature behavior of γ-Fe2SiO4 (spinel) based on static compression measurements at 400° C

    NASA Astrophysics Data System (ADS)

    Plymate, T. G.; Stout, J. H.

    1994-10-01

    Thirteen energy-dispersive x-ray diffraction spectra for γ-Fe2SiO4 (spinel) collected in situ at 400° C and pressures to 24 GPa constitute the basis for an elevated-temperature static compression isotherm for this important high-pressure phase. A Murnaghan regression of these molar volume measurements yields 177.3 (±17.4) GPa and 5.4(±2.5) for the 400° C, room pressure values of the isothermal bulk modulus ( K P 0) and its first pressure derivative ( K' P 0), respectively. When compared to the room- Tdeterminations of K P 0 available in the literature, our 400° C K P 0 yields -4.1 (±6.2)×10-2 GPa/degree for the average value of (∂ K/∂ T) P 0 over the temperature interval 25° Cpressure of the 400 km discontinuity suggests a ΔV R of approximately 8.4% at that depth, approximately 10% less than the 9.3% ΔV R at ambient conditions.

  2. Hypertension (High Blood Pressure)

    MedlinePlus

    ... Loss Surgery? A Week of Healthy Breakfasts Shyness Hypertension (High Blood Pressure) KidsHealth > For Teens > Hypertension (High Blood Pressure) A ... rest temperature diet emotions posture medicines Why Is High Blood Pressure Bad? High blood pressure means a person's heart ...

  3. 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.

  4. Constant-pressure Blowers

    NASA Technical Reports Server (NTRS)

    Sorensen, E

    1940-01-01

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

  5. 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 (τ=5,3 ms) than thermistors (τ=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

  6. 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

  7. 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.

  8. Mechanical buckling of artery under pulsatile pressure.

    PubMed

    Liu, Qin; Han, Hai-Chao

    2012-04-30

    Tortuosity that often occurs in carotid and other arteries has been shown to be associated with high blood pressure, atherosclerosis, and other diseases. However the mechanisms of tortuosity development are not clear. Our previous studies have suggested that arteries buckling could be a possible mechanism for the initiation of tortuous shape but artery buckling under pulsatile flow condition has not been fully studied. The objectives of this study were to determine the artery critical buckling pressure under pulsatile pressure both experimentally and theoretically, and to elucidate the relationship of critical pressures under pulsatile flow, steady flow, and static pressure. We first tested the buckling pressures of porcine carotid arteries under these loading conditions, and then proposed a nonlinear elastic artery model to examine the buckling pressures under pulsatile pressure conditions. Experimental results showed that under pulsatile pressure arteries buckled when the peak pressures were approximately equal to the critical buckling pressures under static pressure. This was also confirmed by model simulations at low pulse frequencies. Our results provide an effective tool to predict artery buckling pressure under pulsatile pressure.

  9. 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)

  10. Blood Pressure Quiz

    MedlinePlus

    ... high blood pressure can lead to… stroke. kidney failure. heart attack and heart failure. all of the above. ... high blood pressure can lead to stroke, kidney failure, heart attack and heart failure A is the correct ...

  11. High Blood Pressure Prevention

    MedlinePlus

    ... version of this page please turn Javascript on. High Blood Pressure Prevention Steps You Can Take You can take steps to prevent high blood pressure by adopting these healthy lifestyle habits. Follow a ...

  12. Low blood pressure

    MedlinePlus

    Hypotension; 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 problems for ...

  13. High blood pressure - infants

    MedlinePlus

    ... medlineplus.gov/ency/article/007329.htm High blood pressure - infants To use the sharing features on this page, please enable JavaScript. High blood pressure (hypertension) is an increase in the force of ...

  14. Blood Pressure Test

    MedlinePlus

    ... a minute to complete a single blood pressure measurement. After the procedure The nurse or technician taking ... online record. You can learn your blood pressure measurement as soon as your test is over. A ...

  15. 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, ...

  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. Pressure surge attenuator

    DOEpatents

    Christie, Alan M.; Snyder, Kurt I.

    1985-01-01

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

  18. The Root Pressure Phenomenon

    ERIC Educational Resources Information Center

    Marsh, A. R.

    1972-01-01

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

  19. Pressure-sensitive optrode

    DOEpatents

    Hirschfeld, Tomas B.

    1986-01-01

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

  20. Pressure-sensitive optrode

    DOEpatents

    Hirschfeld, T.B.

    1986-07-15

    An apparatus is provided for sensing changes in pressure and for generating optical signals related to said changes in pressure. Light from a fiber optic illuminates a fluorescent composition causing it to fluoresce. The fluorescent composition is caused to fluoresce more relative to the end of the fiber optic in response to changes in pressure so that the intensity of fluorescent emissions collected by the same fiber optic used for illumination varies monotonically with pressure. 10 figs.

  1. 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

  2. Brain Pressure Monitoring

    NASA Technical Reports Server (NTRS)

    1977-01-01

    A transducer originally used to measure air pressure in aircraft wind tunnel tests is the basis for a development important in diagnosis and treatment of certain types of brain damage. A totally implantable device, tbe intracranial pressure monitor measures and reports brain pressure by telemetry.

  3. High Blood Pressure (Hypertension)

    MedlinePlus

    ... For Consumers Consumer Information by Audience For Women High Blood Pressure (Hypertension) Share Tweet Linkedin Pin it More sharing options ... En Español Who is at risk? How is high blood pressure treated? Understanding your blood pressure: What do the ...

  4. Understanding Blood Pressure Readings

    MedlinePlus

    ... Disease Venous Thromboembolism Aortic Aneurysm More Understanding Blood Pressure Readings Updated:Mar 22,2017 What do your ... it’s too high for blood pressure High Blood Pressure • Home • Get the Facts About HBP • Know Your ...

  5. Low Blood Pressure

    MedlinePlus

    ... Disease Venous Thromboembolism Aortic Aneurysm More Low Blood Pressure - When Blood Pressure Is Too Low Updated:Dec 13,2016 How ... content was last reviewed October 2016 High Blood Pressure • Home • Get the Facts About HBP Introduction What ...

  6. Treating High Blood Pressure

    MedlinePlus

    About High Blood Pressure Many people in the United States die from high blood pressure. This condition usually does not cause symptoms. Most ... until it is too late. A person has high blood pressure when the blood pushes against Visit your doctor ...

  7. A soundproof pressure chamber.

    PubMed

    Kitahara, M; Kodama, A; Ozawa, H; Inoue, S

    1994-01-01

    For neurotological research we designed a soundproof pressure chamber in which pressure can be adjusted +/- 1000 mmH2O at the rate of less than 100 mmH2O per second. Noise in the chamber can be maintained under 30-35 dB while pressure is kept at a given level.

  8. Skin (Pressure) Sores

    MedlinePlus

    ... Treatments and Side Effects Managing Cancer-related Side Effects Skin Problems Pressure Sores A skin or pressure sore ... Content Usage Policy . Skin Problems Dry Skin Itching Skin Color Changes Pressure Sores Scars ... and Paying for Treatment Treatments and Side Effects Survivorship: During and After Treatment Caregivers and Family ...

  9. An automated method for measuring static pressure-volume curves of the respiratory system and its application in healthy lungs and after lung damage by oleic acid infusion.

    PubMed

    Zhao, Y; Rees, S E; Kjaergaard, S; Smith, B W; Larsson, A; Andreassen, S

    2007-03-01

    Elastic pressure/volume (PV) curves of the respiratory system have attracted increasing interest, because they may be helpful to optimize ventilator settings in patients undergoing mechanical ventilation. Clinically applicable methods need to be fast, use routinely available equipment, draw the inspiratory and expiratory PV curve limbs, separate the resistive and viscoelastic properties of the respiratory system from the elastic properties, and provide reproducible measurements. This paper presents a computer-controlled method for rapid measurements of static PV curves using a long inflation-deflation with pauses, and its evaluation in six pigs before and after lung damage caused by oleic acid. The method is fast, i.e. 20.5 +/- 1.9 s (mean +/- SD) in healthy lungs and 17.7 +/- 4.1 s in diseased lungs, this including inspiratory and expiratory pauses of 1.1 s duration. In addition the only equipment used was a clinical ventilator and a PC. For healthy and damaged lungs expiratory PV curve limbs were very reproducible and were at higher volume than the inspiratory limbs, indicating hysteresis. For damaged lungs inspiratory PV limbs were reproducible. For healthy lungs the inspiratory limbs were reproducible but only after the first inflation-deflation. It is possible that during the first inflation alveoli are recruited which are not derecruited on deflation, shifting the inspiratory limb of the PV curve. The paused long inflation-deflation technique provides a quick, automated measurement of static PV curves on both inspiratory and expiratory limbs using routinely available equipment in the intensive care unit.

  10. Pressure sensitive conductive rubber blends

    SciTech Connect

    Hassan, H.H. ); Abdel-Bary, E.M. ); El-Mansy, M.K.; Khodair, H.A. )

    1989-12-01

    Butadiene-acrylonitrile rubber (NBR) was blended with polychloroprene (CR) according to standard techniques. The blend was mixed with different concentrations of ZnO. The vulcanized sample was subjected to electrical conductivity ({sigma}) measurements while different values of static pressure were applied on the sample. It was found that samples containing 7.5 phr ZnO showed a reasonable pressure sensitive increase of {sigma}. Furthermore, the {sigma} vs pressure relationship of rubber blend mixed with different concentrations of Fast Extrusion Furnace black (FEF) was investigated. It was found that rubber vulcanizate containing 40 phr FEF resulted in a negative value of the pressure coefficient of conductivity {approx equal} {minus} 4.5 KPa{sup {minus}1}.

  11. Reduction of Orifice-Induced Pressure Errors

    NASA Technical Reports Server (NTRS)

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

    1987-01-01

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

  12. Pressure Relief Devices

    NASA Astrophysics Data System (ADS)

    Manha, William D.

    2010-09-01

    Pressure relief devices are used in pressure systems and on pressure vessels to prevent catastrophic rupture or explosion from excessive pressure. Pressure systems and pressure vessels have manufacturers maximum rated operating pressures or maximum design pressures(MDP) for which there are relatively high safety factors and minimum risk of rupture or explosion. Pressure systems and pressure vessels that have a potential to exceed the MDP by being connected to another higher pressure source, a compressor, or heat to water(boiler) are required to have over-pressure protecting devices. Such devices can be relief valves and/or burst discs to safely relieve potentially excessive pressure and prevent unacceptable ruptures and explosions which result in fail-safe pressure systems and pressure vessels. Common aerospace relief valve and burst disc requirements and standards will be presented. This will include the NASA PSRP Interpretation Letter TA-88-074 Fault Tolerance of Systems Using Specially Certified Burst Disks that dictates burst disc requirements for payloads on Shuttle. Two recent undesirable manned space payloads pressure relief devices and practices will be discussed, as well as why these practices should not be continued. One example for discussion is the use of three burst discs that have been placed in series to comply with safety requirements of three controls to prevent a catastrophic hazard of the over-pressurization and rupture of pressure system and/or vessels. The cavities between the burst discs are evacuated and are the reference pressures for activating the two upstream burst discs. If the upstream burst disc leaks into the reference cavity, the reference pressure increases and it can increase the burst disc activating pressure and potentially result in the burst disc assembly being ineffective for over pressure protection. The three burst discs-in-series assembly was found acceptable because the burst discs are designed for minimum risk(DFMR) of

  13. Dynamic Pressure Calibration Standard

    NASA Technical Reports Server (NTRS)

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

    1986-01-01

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

  14. 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.

  15. Pressure reducing regulator

    DOEpatents

    Whitehead, John C.; Dilgard, Lemoyne W.

    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.

  16. Miniaturized pressurization system

    DOEpatents

    Whitehead, John C.; Swink, Don G.

    1991-01-01

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

  17. Pressure (Or No Royal Road)

    ERIC Educational Resources Information Center

    Bradley, J.

    1973-01-01

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

  18. Pressure locking test results

    SciTech Connect

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

    1996-12-01

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

  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. Measurement of endolymphatic pressure.

    PubMed

    Mom, T; Pavier, Y; Giraudet, F; Gilain, L; Avan, P

    2015-04-01

    Endolymphatic pressure measurement is of interest both to researchers in the physiology and pathophysiology of hearing and ENT physicians dealing with Menière's disease or similar conditions. It is generally agreed that endolymphatic hydrops is associated with Menière's disease and is accompanied by increased hydrostatic pressure. Endolymphatic pressure, however, cannot be measured precisely without endangering hearing, making the association between hydrops and increased endolymphatic pressure difficult to demonstrate. Several integrated in vivo models have been developed since the 1960s, but only a few allow measurement of endolymphatic hydrostatic pressure. Models associating measurement of hydrostatic pressure and endolymphatic potential and assessment of cochlear function are of value to elucidate the pathophysiology of endolymphatic hydrops. The present article presents the main types of models and discusses their respective interest.

  1. 46 CFR 197.462 - Pressure vessels and pressure piping.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 7 2012-10-01 2012-10-01 false Pressure vessels and pressure piping. 197.462 Section... Diving Equipment § 197.462 Pressure vessels and pressure piping. (a) The diving supervisor shall ensure that each pressure vessel, including each volume tank, cylinder and PVHO, and each pressure...

  2. 46 CFR 197.462 - Pressure vessels and pressure piping.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 7 2010-10-01 2010-10-01 false Pressure vessels and pressure piping. 197.462 Section... Diving Equipment § 197.462 Pressure vessels and pressure piping. (a) The diving supervisor shall ensure that each pressure vessel, including each volume tank, cylinder and PVHO, and each pressure...

  3. 46 CFR 197.462 - Pressure vessels and pressure piping.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 7 2013-10-01 2013-10-01 false Pressure vessels and pressure piping. 197.462 Section... Diving Equipment § 197.462 Pressure vessels and pressure piping. (a) The diving supervisor shall ensure that each pressure vessel, including each volume tank, cylinder and PVHO, and each pressure...

  4. 46 CFR 197.462 - Pressure vessels and pressure piping.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 7 2014-10-01 2014-10-01 false Pressure vessels and pressure piping. 197.462 Section... Diving Equipment § 197.462 Pressure vessels and pressure piping. (a) The diving supervisor shall ensure that each pressure vessel, including each volume tank, cylinder and PVHO, and each pressure...

  5. 46 CFR 197.462 - Pressure vessels and pressure piping.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 7 2011-10-01 2011-10-01 false Pressure vessels and pressure piping. 197.462 Section... Diving Equipment § 197.462 Pressure vessels and pressure piping. (a) The diving supervisor shall ensure that each pressure vessel, including each volume tank, cylinder and PVHO, and each pressure...

  6. Pressure cryocooling protein crystals

    DOEpatents

    Kim, Chae Un; Gruner, Sol M.

    2011-10-04

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

  7. Postoperative permanent pressure alopecia.

    PubMed

    Chang, Zi Yun; Ngian, Jan; Chong, Claudia; Chong, Chin Ted; Liew, Qui Yin

    2016-04-01

    A 49-year-old Chinese female underwent elective laparoscopic assisted Whipple's surgery lasting 12 h. This was complicated by postoperative pressure alopecia at the occipital area of the scalp. Pressure-induced hair loss after general anaesthesia is uncommon and typically temporary, but may be disconcerting to the patient. We report this case of postoperative permanent pressure alopecia due to its rarity in the anaesthesia/local literature, and review the risk factors for its development.

  8. High temperature pressure gauge

    DOEpatents

    Echtler, J. Paul; Scandrol, Roy O.

    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.

  9. Controlling your high blood pressure

    MedlinePlus

    ... ency/patientinstructions/000101.htm Controlling your high blood pressure To use the sharing features on this page, ... blood pressure goes up. When is Your Blood Pressure a Concern? If your blood pressure is high, ...

  10. Attachment Fitting for Pressure Vessel

    NASA Technical Reports Server (NTRS)

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

    2002-01-01

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

  11. Sapphire tube pressure vessel

    SciTech Connect

    Outwater, J.O.

    2000-05-23

    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.

  12. Pressurized fluidized bed reactor

    DOEpatents

    Isaksson, J.

    1996-03-19

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

  13. Pressurized fluidized bed reactor

    DOEpatents

    Isaksson, Juhani

    1996-01-01

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

  14. Pressure-sensitive optrode

    DOEpatents

    Hirschfeld, T.B.

    1982-09-30

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

  15. Pressure-sensitive optrode

    DOEpatents

    Hirschfeld, Tomas B.

    1985-01-01

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

  16. 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.

  17. Increased intracranial pressure

    MedlinePlus

    ... brain. Many conditions can increase intracranial pressure. Common causes include: Aneurysm rupture and subarachnoid hemorrhage Brain tumor Encephalitis Head injury Hydrocephalus (increased fluid around ...

  18. Atracurium and intraocular pressure.

    PubMed Central

    Murphy, D F; Eustace, P; Unwin, A; Magner, J B

    1985-01-01

    The effect of atracurium on intraocular pressure was studied by comparing it with pancuronium in a randomised controlled trial. The intraocular pressure was measured in patients undergoing cataract surgery before administration of the muscle relaxant, at 1, 3, and 5 minutes after its administration, and at 1 minute after tracheal intubation. Atracurium was found to decrease intraocular pressure to a significantly greater degree than pancuronium. The intraocular pressure after tracheal intubation was found to be significantly higher than that measured immediately after induction of anaesthesia. The authors conclude that atracurium provides an acceptable alternative to pancuronium for ophthalmic surgery but does not overcome the ocular hypertensive effect of tracheal intubation. PMID:3899166

  19. 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.

  20. Sapphire tube pressure vessel

    DOEpatents

    Outwater, John O.

    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.

  1. Electrolytic pressure transduction system

    NASA Astrophysics Data System (ADS)

    Bryant, G. H.

    1985-12-01

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

  2. Basic Equations in Statics and Kinetics of Protein Polymerization and the Mechanism of the Formation and Dissociation of Amyloid Fibrils Revealed by Pressure Perturbation.

    PubMed

    Tachibana, Hideki

    2015-01-01

    Studies of the pressure-dissociation of several amyloid or amyloid-like fibrils have shown that the fibril state is considerably voluminous. Quantitative characterization of the protein fibrillation reaction with respect to volumetric parameters is necessary to elucidate mechanisms of amyloid fibrillation in molecular terms such as protein cavity and hydration. Here we discuss, firstly, basic equations in statics and kinetics of protein polymerization as employed to obtain thermodynamic, volumetric, and kinetic parameters. Equilibrium treatment of the reactions with the scheme such as one-step polymerization, linear-association polymerization, or nucleation-dependent polymerization, and kinetic treatment of seeded linear-polymerization or spontaneous nucleation-elongation polymerization are described. In particular we will detail kinetics of the dissociation of fibrils which have been produced under the linear-association mechanism and therefore the length-distribution of which conforms to a geometric sequence in the degree of polymerization with a common ratio r, which is less than, and usually very close to, unity. In this case, an observed macroscopic rate of dissociation is shown to be a product of the microscopic elementary dissociation rate constant and a factor (1-r), extremely reduced compared with the intrinsic elementary rate. Secondly, we discuss protein conformational states in fibrillogenesis with molecular and volumetric observations reported, such as the unfolded state responsible for the association with seeds and the extension of amyloid fibrils, the transition state in which protein cavity formation and dehydration occur to intermediate levels, and the fibril state in which they occur to final respective levels which, in some cases, depend on the maturity of the fibril.

  3. 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.

  4. Dual shell pressure balanced vessel

    DOEpatents

    Fassbender, Alexander G.

    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.

  5. Neonatal Pressure Ulcer Prevention.

    PubMed

    Scheans, Patricia

    2015-01-01

    The incidence of pressure ulcers in acutely ill infants and children ranges up to 27 percent in intensive care units, with a range of 16-19 percent in NICUs. Anatomic, physiologic, and developmental factors place ill and preterm newborns at risk for skin breakdown. Two case studies illustrate these factors, and best practices for pressure ulcer prevention are described.

  6. Pressure vessel flex joint

    NASA Technical Reports Server (NTRS)

    Kahn, Jon B. (Inventor)

    1992-01-01

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

  7. 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.

  8. Pseudophakia and intraocular pressure.

    PubMed

    Radius, R L; Schultz, K; Sobocinski, K; Schultz, R O; Easom, H

    1984-06-01

    We studied the change in intraocular pressure in 373 consecutive eyes undergoing cataract extraction with intraocular lens implantation between Jan. 1, 1981, and May 31, 1982. There was a mean increase in intraocular pressure of 0.1 mm Hg following this surgery. This increase, however, was not statistically significant (P greater than .5). There was a mean rise in pressure of 0.8 mm Hg in the eyes undergoing intracapsular surgery and a mean fall in pressure of 0.6 mm Hg in the eyes undergoing extracapsular surgery (P less than .05). The change in pressure was unrelated to age, surgeon, or lens type. The results of a separate analysis of 16 eyes with a preoperative diagnosis of glaucoma and eight eyes with ocular hypertension were similar.

  9. High Temperature Dynamic Pressure Measurements Using Silicon Carbide Pressure Sensors

    NASA Technical Reports Server (NTRS)

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

    2014-01-01

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

  10. Pressurizer tank upper support

    DOEpatents

    Baker, Tod H.; Ott, Howard L.

    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.

  11. 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.

  12. [Measuring blood pressure].

    PubMed

    Estrada Reventos, Dolors; Pujol Navarro, Ester

    2008-09-01

    High blood pressure is one of the main factors which lead to cardiovascular cerebral-vascular and kidney diseases; therefore, nursing professionals should have enough basic knowledge to enable them to carry out a precocious diagnosis and correct follow-up procedures. Although students in nursing schools are taught how to correctly measure blood pressure, often this teaching does not meet the recommendations provided by different national and international guidelines. Thus it is important to know how to use the correct methodology to measure blood pressure.

  13. 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.

  14. SENSITIVE PRESSURE GAUGE

    DOEpatents

    Ball, W.P.

    1961-01-01

    An electron multiplier device is described. It has a plurality of dynodes between an anode and cathode arranged to measure pressure, temperature, or other environmental physical conditions that proportionately iinfuences the quantity of gas molecules between the dynodes. The output current of the device is influenced by the reduction in electron multiplication at the dynodes due to energy reducing collisions of the electrons with the gas molecules between the dynodes. More particularly, the current is inversely proportional to the quantity of gas molecules, viz., the gas pressure. The device is, hence, extremely sensitive to low pressures.

  15. Planets under pressure

    NASA Astrophysics Data System (ADS)

    Jeanloz, Raymond

    2009-04-01

    Deep inside the planet Jupiter, diamonds hail down from hydrocarbon clouds as intense atmospheric pressures break methane into its atomic components. Further in - but still only 15% of the way to the planet's centre - the pressure reaches a million times that of the Earth's atmosphere. This is enough to transform hydrogen from the transparent, insulating gas we know at our planet's surface into a metallic fluid that sustains Jupiter's huge magnetic field. Even diamond is not forever: at pressures of 8-10 million atmospheres it is transformed into an opaque, metallic form of carbon, rather than the familiar transparent crystal.

  16. Pressure Ulcer Prevention

    PubMed Central

    2009-01-01

    Executive Summary In April 2008, the Medical Advisory Secretariat began an evidence-based review of the literature concerning pressure ulcers. Please visit the Medical Advisory Secretariat Web site, http://www.health.gov.on.ca/english/providers/program/mas/tech/tech_mn.html to review these titles that are currently available within the Pressure Ulcers series. Pressure ulcer prevention: an evidence based analysis The cost-effectiveness of prevention strategies for pressure ulcers in long-term care homes in Ontario: projections of the Ontario Pressure Ulcer Model (field evaluation) Management of chronic pressure ulcers: an evidence-based analysis (anticipated pubicstion date - mid-2009) Purpose A pressure ulcer, also known as a pressure sore, decubitus ulcer, or bedsore, is defined as a localized injury to the skin/and or underlying tissue occurring most often over a bony prominence and caused by pressure, shear, or friction, alone or in combination. (1) Those at risk for developing pressure ulcers include the elderly and critically ill as well as persons with neurological impairments and those who suffer conditions associated with immobility. Pressure ulcers are graded or staged with a 4-point classification system denoting severity. Stage I represents the beginnings of a pressure ulcer and stage IV, the severest grade, consists of full thickness tissue loss with exposed bone, tendon, and or muscle. (1) In a 2004 survey of Canadian health care settings, Woodbury and Houghton (2) estimated that the prevalence of pressure ulcers at a stage 1 or greater in Ontario ranged between 13.1% and 53% with nonacute health care settings having the highest prevalence rate (Table 1). Executive Summary Table 1: Prevalence of Pressure Ulcers* Setting Canadian Prevalence,% (95% CI) Ontario Prevalence,Range % (n) Acute care 25 (23.8–26.3) 23.9–29.7 (3418) Nonacute care† 30 (29.3–31.4) 30.0–53.3 (1165) Community care 15 (13.4–16.8) 13.2 (91) Mixed health care‡ 22 (20.9

  17. 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.

  18. Hypertension (High Blood Pressure)

    MedlinePlus

    ... the results of observational studies further strengthened the causal relationship between high blood pressure and CVD, and ... disease, and those who have additional known risk factors for CVD. SPRINT will also provide information on ...

  19. High Blood Pressure (Hypertension)

    MedlinePlus

    ... already been diagnosed with high blood pressure. Try yoga and meditation. Yoga and meditation not only can strengthen your body ... Accessed Sept. 21, 2015. Hu B, et al. Effects of psychological stress on hypertension in middle-aged ...

  20. 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.

  1. High Blood Pressure (Hypertension)

    MedlinePlus

    ... Neuropathy Foot Complications DKA (Ketoacidosis) & Ketones Kidney Disease (Nephropathy) High Blood Pressure (Hypertension) Stroke Hyperosmolar Hyperglycemic Nonketotic Syndrome (HHNS) Gastroparesis Heart Disease Mental Health Pregnancy Related Conditions donate en -- Make Your Donation Count - ...

  2. Preventing pressure ulcers

    MedlinePlus

    ... skin in this area. If you use a Wheelchair Make sure your wheelchair is the right size for you. Have your ... physical therapist to check how you fit your wheelchair. If you feel pressure anywhere, have your doctor ...

  3. Nonlinear optomechanical pressure

    NASA Astrophysics Data System (ADS)

    Conti, Claudio; Boyd, Robert

    2014-03-01

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

  4. High Blood Pressure (Hypertension)

    MedlinePlus

    ... Practice healthy coping techniques, such as muscle relaxation, deep breathing or meditation. Getting regular physical activity and ... blood pressure at home. Practice relaxation or slow, deep breathing. Practice taking deep, slow breaths to help ...

  5. On Time Performance Pressure

    NASA Technical Reports Server (NTRS)

    Connell, Linda; Wichner, David; Jakey, Abegael

    2013-01-01

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

  6. Normal pressure hydrocephalus (NPH)

    MedlinePlus

    ... cerebrospinal fluid (CSF) in the brain that affects brain function. However, the pressure of the fluid is usually ... shunt that does not work well) Loss of brain function ( dementia ) that becomes worse over time Injury from ...

  7. Pressurized Vessel Slurry Pumping

    SciTech Connect

    Pound, C.R.

    2001-09-17

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

  8. Internal pressure sensor

    DOEpatents

    Dowalo, James A [Blackfoot, ID

    2010-03-16

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

  9. Capacitance pressure sensor

    DOEpatents

    Eaton, William P.; Staple, Bevan D.; Smith, James H.

    2000-01-01

    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).

  10. Choosing Blood Pressure Medications

    MedlinePlus

    ... doctor might first suggest diuretics, which remove excess water and sodium from your body. That decreases the amount of fluid flowing through your blood vessels, which reduces pressure on your vessel walls. There are three types of diuretics: thiazide, loop ...

  11. Gasoline Reid Vapor Pressure

    EPA Pesticide Factsheets

    EPA regulates the vapor pressure of gasoline sold at retail stations during the summer ozone season to reduce evaporative emissions from gasoline that contribute to ground-level ozone and diminish the effects of ozone-related health problems.

  12. Normal Pressure Hydrocephalus

    MedlinePlus

    ... techniques and neuroimaging, and finding improved treatments and preventions. Information from the National Library of Medicine’s MedlinePlus Normal Pressure Hydrocephalus × What research is being ...

  13. Low Blood Pressure (Hypotension)

    MedlinePlus

    ... Alpha blockers, such as prazosin (Minipress) and labetalol Beta blockers, such as atenolol (Tenormin), propranolol (Inderal, Innopran XL, ... drugs used to treat high blood pressure — diuretics, beta blockers, calcium channel blockers and angiotensin-converting enzyme (ACE) ...

  14. Radial pressure flange seal

    DOEpatents

    Batzer, Thomas H.; Call, Wayne R.

    1989-01-01

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

  15. Radial pressure flange seal

    DOEpatents

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

    1989-01-24

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

  16. Pressure multiplying dispenser

    DOEpatents

    DeFord, Henry S.; Moss, Owen R.

    1986-01-01

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

  17. 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.

  18. ECN Pressure Test

    SciTech Connect

    Dixon, K.; /Fermilab

    1991-07-18

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

  19. 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.

  20. 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

  1. Measurement of unsteady surface pressure on rotor blades of fans by pressure-sensitive paint

    NASA Astrophysics Data System (ADS)

    Yokoyama, Hiroshi; Miura, Kouhei; Iida, Akiyoshi

    2017-01-01

    To clarify the unsteady pressure distributions on the rotor blades of an axial fan, a pressure-sensitive paint (PSP) technique was used. To capture the image of the rotating fan as a static image, an optical derotator method with a dove prism was adopted. It was confirmed by preliminary experiments with a resonator and a speaker that the pressure fluctuations with 347 Hz can be measured by the present PSP. The measured mean pressure distributions were compared with the predicted results based on large-eddy simulations. The measured instantaneous surface pressure is instrumental to identify acoustic source of fan noise in the design stage.

  2. Helping Teens Resist Sexual Pressure

    MedlinePlus

    ... Size Email Print Share Helping Teens Resist Sexual Pressure Page Content Article Body Teens are more likely ... time they had intercourse. Helping Teens Resist Sexual Pressure “The pressure on teenagers to have sex is ...

  3. Prevention of High Blood Pressure

    MedlinePlus

    ... the NHLBI on Twitter. Prevention of High Blood Pressure Healthy lifestyle habits, proper use of medicines, and ... blood pressure or its complications. Preventing High Blood Pressure Onset Healthy lifestyle habits can help prevent high ...

  4. Blood pressure monitors for home

    MedlinePlus

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

  5. 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.

  6. Optical zero-differential pressure switch and its evaluation in a multiple pressure measuring system

    NASA Technical Reports Server (NTRS)

    Powell, J. A.

    1977-01-01

    The design of a clamped-diaphragm pressure switch is described in which diaphragm motion is detected by a simple fiber-optic displacement sensor. The switch was evaluated in a pressure measurement system where it detected the zero crossing of the differential pressure between a static test pressure and a tank pressure that was periodically ramped from near zero to fullscale gage pressure. With a ramping frequency of 1 hertz and a full-scale tank pressure of 69 N/sq cm gage (100 psig), the switch delay was as long as 2 milliseconds. Pressure measurement accuracies were 0.25 to 0.75 percent of full scale. Factors affecting switch performance are also discussed.

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

    SciTech Connect

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

    2010-06-15

    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.

  8. Commonwealth Edison Company pressure locking test report

    SciTech Connect

    Bunte, B.D.; Kelly, J.F.

    1996-12-01

    Pressure Locking is a phenomena which can cause the unseating thrust for a gate valve to increase dramatically from its typical static unseating thrust. This can result in the valve actuator having insufficient capability to open the valve. In addition, this can result in valve damage in cases where the actuator capability exceeds the valve structural limits. For these reasons, a proper understanding of the conditions which may cause pressure locking and thermal binding, as well as a methodology for predicting the unseating thrust for a pressure locked or thermally bound valve, are necessary. This report discusses the primary mechanisms which cause pressure locking. These include sudden depressurization of piping adjacent to the valve and pressurization of fluid trapped in the valve bonnet due to heat transfer. This report provides a methodology for calculating the unseating thrust for a valve which is pressure locked. This report provides test data which demonstrates the accuracy of the calculation methodology.

  9. Cryogenic High Pressure Sensor Module

    NASA Technical Reports Server (NTRS)

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

    1999-01-01

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

  10. Cryogenic, Absolute, High Pressure Sensor

    NASA Technical Reports Server (NTRS)

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

    2001-01-01

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

  11. 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.

  12. Flow compensating pressure regulator

    NASA Technical Reports Server (NTRS)

    Baehr, E. F. (Inventor)

    1978-01-01

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

  13. Passive blast pressure sensor

    DOEpatents

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

    2013-03-19

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

  14. 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.

  15. Pressure suppression containment system

    DOEpatents

    Gluntz, Douglas M.; Townsend, Harold 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.

  16. Magnetostrictive Pressure Regulating System

    NASA Technical Reports Server (NTRS)

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

    2013-01-01

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

  17. Pressure settling of mesophase

    SciTech Connect

    Romine, H.E.

    1989-05-23

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

  18. Circumferential pressure probe

    NASA Technical Reports Server (NTRS)

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

    1989-01-01

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

  19. PRESSURE SENSING DEVICE

    DOEpatents

    Pope, K.E.

    1959-12-15

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

  20. Pressure driven particulate flows

    SciTech Connect

    Ingher, M.S.; Mondy, L.A.

    1996-03-01

    Numerical simulations of pressure-driven particulate Stokes flows are performed in cylindrical and rectangular conduits using a parallel boundary element code. Spherical particles are randomly placed in the conduits and a pressure drop between the ends of the conduits is imposed by the boundary conditions to induce a Poiseuille-like flow field. The instantaneous velocities of the particles are then calculated, as well as the additional pressure drop necessary to maintain a constant flow rate. Because the results depend on the spatial distribution of the particles, several random configurations of particles are examined for each case. Depending on two different interpretations of the numerical results, the solid phase can be represented as either leading or lagging the fluid phase. Both of the analyses and interpretations are presented.

  1. Oxygen partial pressure sensor

    DOEpatents

    Dees, D.W.

    1994-09-06

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

  2. Oxygen partial pressure sensor

    DOEpatents

    Dees, Dennis W.

    1994-01-01

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

  3. HIGH PRESSURE GAS REGULATOR

    DOEpatents

    Ramage, R.W.

    1962-05-01

    A gas regulator operating on the piston and feedback principle is described. The device is particularly suitable for the delicate regulation of high pressure, i.e., 10,000 psi and above, gas sources, as well as being perfectly adaptable for use on gas supplies as low as 50 psi. The piston is adjustably connected to a needle valve and the movement of the piston regulates the flow of gas from the needle valve. The gas output is obtained from the needle valve. Output pressure is sampled by a piston feedback means which, in turn, regulates the movement of the main piston. When the output is other than the desired value, the feedback system initiates movement of the main piston to allow the output pressure to be corrected or to remain constant. (AEC)

  4. 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.

  5. Variable pressure washer

    NASA Technical Reports Server (NTRS)

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

    2004-01-01

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

  6. Pressure thermal holograms

    NASA Astrophysics Data System (ADS)

    Toxqui-Lopez, S.; Olivares-Perez, A.; Fuentes-Tapia, I.

    2005-04-01

    A new recorder material with the ability to store information by pressure and temperature parameters, computer phase holograms were obtained whit this material, which it is used a coating of polyester resin mixing with nitrocellulose. The major improvements from our material are: high diffraction efficiency (91.9 %), reduced cost, easily to apply on any substrate and the hologram is making with out develop process, and this does not need carefully controlled environment conditions. In this approach the hologram is formed under pressure and temperature.

  7. Wellbore pressure transducer

    DOEpatents

    Shuck, Lowell Z.

    1979-01-01

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

  8. 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.

  9. Krypton oxides under pressure.

    PubMed

    Zaleski-Ejgierd, Patryk; Lata, Pawel M

    2016-02-02

    Under high pressure, krypton, one of the most inert elements is predicted to become sufficiently reactive to form a new class of krypton compounds; krypton oxides. Using modern ab-initio evolutionary algorithms in combination with Density Functional Theory, we predict the existence of several thermodynamically stable Kr/O species at elevated pressures. In particular, our calculations indicate that at approx. 300 GPa the monoxide, KrO, should form spontaneously and remain thermo- and dynamically stable with respect to constituent elements and higher oxides. The monoxide is predicted to form non-molecular crystals with short Kr-O contacts, typical for genuine chemical bonds.

  10. Test Your Blood Pressure IQ

    MedlinePlus

    ... How High Blood Pressure is Diagnosed BP vs. Heart Rate Low Blood Pressure Resistant Hypertension Pulmonary Hypertension High Blood Pressure Myths ... Healthy 6 What are the Symptoms of High Blood Pressure? 7 All About Heart Rate (Pulse) 8 Tachycardia | Fast Heart Rate 9 Warning ...

  11. GOLD PRESSURE VESSEL SEAL

    DOEpatents

    Smith, A.E.

    1963-11-26

    An improved seal between the piston and die member of a piston-cylinder type pressure vessel is presented. A layer of gold, of sufficient thickness to provide an interference fit between the piston and die member, is plated on the contacting surface of at least one of the members. (AEC)

  12. Low pressure hydrocyclone separator

    SciTech Connect

    Flanigan, D.A.; Stolhand, J.E.

    1989-07-04

    This patent describes a method of separating a dispersed phase liquid from a bulk phase liquid of a liquid-liquid mixture, the dispersed phase and bulk phase liquids having different densities. The method comprises the steps of: providing a supply of the liquid-liquid mixture at a first pressure; providing a pump means including means for minimizing degradation of the volumetric means size of droplets of the dispersed phase further including a pump size for maintaining the pump means at substantially near maximum flow rate capacity; pumping the liquid-liquid mixture with at least one pump means to a second pressure such that a differential between the first and second pressures is not substantially greater than a differential pressure at which the pump means begins to substantially degrade the volumetric mean size of droplets of the dispersed phase liquid passing therethrough, the pumping without substantial droplet degradation being achieved by operating the pump means at relatively near its maximum flow rate capacity to substantially reduce on a percentage basis the effect of fluid slippage within the pump means; directing the liquid-liquid mixture from the pump means to a hydrocyclone; and separating a substantial portion of the dispersed phase liquid from the liquid-liquid mixture in the hydrocyclone.

  13. 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…

  14. Reactor pressure vessel nozzle

    DOEpatents

    Challberg, Roy C.; Upton, Hubert A.

    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.

  15. 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.

  16. The Pressure Group Cooker.

    ERIC Educational Resources Information Center

    Graves, Bill

    1992-01-01

    Administrators across the nation have encountered vigorous challenges against textbooks, practices, and procedures that critics find laden with occult and New Age values. Attacks are becoming more aggressive, better organized, and well financed. This article and accompanying sidebars discuss pressure group tactics and ways to counter them. The…

  17. Putting oysters under pressure

    Technology Transfer Automated Retrieval System (TEKTRAN)

    High pressure processing (HPP) is the most commercially important food processing technology in use now and is anticipated to remain of equal or greater importance during the next five to 10 years. This month’s column reviews the theory and current applications of HPP for oysters to improve their sa...

  18. High Pressure Biomass Gasification

    SciTech Connect

    Agrawal, Pradeep K

    2016-07-29

    According to the Billion Ton Report, the U.S. has a large supply of biomass available that can supplement fossil fuels for producing chemicals and transportation fuels. Agricultural waste, forest residue, and energy crops offer potential benefits: renewable feedstock, zero to low CO2 emissions depending on the specific source, and domestic supply availability. Biomass can be converted into chemicals and fuels using one of several approaches: (i) biological platform converts corn into ethanol by using depolymerization of cellulose to form sugars followed by fermentation, (ii) low-temperature pyrolysis to obtain bio-oils which must be treated to reduce oxygen content via HDO hydrodeoxygenation), and (iii) high temperature pyrolysis to produce syngas (CO + H2). This last approach consists of producing syngas using the thermal platform which can be used to produce a variety of chemicals and fuels. The goal of this project was to develop an improved understanding of the gasification of biomass at high pressure conditions and how various gasification parameters might affect the gasification behavior. Since most downstream applications of synags conversion (e.g., alcohol synthesis, Fischer-Tropsch synthesis etc) involve utilizing high pressure catalytic processes, there is an interest in carrying out the biomass gasification at high pressure which can potentially reduce the gasifier size and subsequent downstream cleaning processes. It is traditionally accepted that high pressure should increase the gasification rates (kinetic effect). There is also precedence from coal gasification literature from the 1970s that high pressure gasification would be a beneficial route to consider. Traditional approach of using thermogravimetric analyzer (TGA) or high-pressure themogravimetric analyzer (PTGA) worked well in understanding the gasification kinetics of coal gasification which was useful in designing high pressure coal gasification processes. However

  19. SOLID GLASS AND CERAMIC EXTERNAL-PRESSURE VESSELS

    DTIC Science & Technology

    characteristics and withstands external pressure cycling and mild underwater dynamic pressures. Scratches on the exterior surfaces do not decrease...appreciably the compressive and elastic strength of such vessels when exposed to either static or cycling pressure. Connectors have been devised that enable

  20. Measuring Blast-Related Intracranial Pressure Within the Human Head

    DTIC Science & Technology

    2010-08-01

    an d stagnation pressures; stagnation pr essure , also called incident pre ssure, consists of static and dynamic pressure combined and subsequent da...represent a n oticeable decrease in IC pr essure that happened before the IC pressure started to increase. This behavior is very noticeable in all

  1. 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.

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

    PubMed Central

    Ivy, Jessica R; Bailey, Matthew A

    2014-01-01

    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

  3. 49 CFR 192.197 - Control of the pressure of gas delivered from high-pressure distribution systems.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 3 2012-10-01 2012-10-01 false Control of the pressure of gas delivered from high... STANDARDS Design of Pipeline Components § 192.197 Control of the pressure of gas delivered from high... external static or control lines. (b) If the maximum actual operating pressure of the distribution...

  4. Pressure Drop in Radiator Air Tubes

    NASA Technical Reports Server (NTRS)

    Parsons, S R

    1921-01-01

    This report describes a method for measuring the drop in static pressure of air flowing through a radiator and shows (1) a reason for the discrepancy noted by various observers between head resistance and drop in pressure; (2) a difference in degree of contraction of the jet in entering a circular cell and a square cell; (3) the ratio of internal frictional resistance to total head resistance for two representative types; (4) the effect of smoothness of surface on pressure gradient; and (5) the effects of supplying heat to the radiator on pressure gradient. The fact that the pressure gradients are found to be approximately proportional to the square of the rate of flow of air appears to indicate turbulent flow, even in the short tubes of the radiator. It was found that the drop in the static pressure in the air stream through a cellular radiator and the pressure gradient in the air tubes are practically proportional to the square of the air flow in a given air density; that the difference between the head resistance per unit area and the fall of static pressure through the air tubes in radiators is apparent rather than real; and that radiators of different types differ widely in the amount of contraction of the jet at entrance. The frictional resistance was found to vary considerably, and in one case to be two-thirds of the head resistance in the type using circular cells and one-half of the head resistance of the radiator type using square cells of approximately the same dimensions.

  5. 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.

  6. Idiopathic Normal Pressure Hydrocephalus

    PubMed Central

    Nassar, Basant R.; Lippa, Carol F.

    2016-01-01

    Idiopathic normal pressure hydrocephalus (iNPH) is a potentially reversible neurodegenerative disease commonly characterized by a triad of dementia, gait, and urinary disturbance. Advancements in diagnosis and treatment have aided in properly identifying and improving symptoms in patients. However, a large proportion of iNPH patients remain either undiagnosed or misdiagnosed. Using PubMed search engine of keywords “normal pressure hydrocephalus,” “diagnosis,” “shunt treatment,” “biomarkers,” “gait disturbances,” “cognitive function,” “neuropsychology,” “imaging,” and “pathogenesis,” articles were obtained for this review. The majority of the articles were retrieved from the past 10 years. The purpose of this review article is to aid general practitioners in further understanding current findings on the pathogenesis, diagnosis, and treatment of iNPH. PMID:28138494

  7. Pressure suppression system

    DOEpatents

    Gluntz, Douglas M.

    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.

  8. 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.

  9. High pressure furnace

    DOEpatents

    Morris, Donald E.

    1993-01-01

    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.

  10. 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.

  11. High pressure oxygen furnace

    DOEpatents

    Morris, Donald E.

    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.

  12. High pressure oxygen furnace

    DOEpatents

    Morris, D.E.

    1992-07-14

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

  13. Continuous pressure letdown system

    DOEpatents

    Sprouse, Kenneth M.; Matthews, David R.; Langowski, Terry

    2010-06-08

    A continuous pressure letdown system connected to a hopper decreases a pressure of a 2-phase (gas and solid) dusty gas stream flowing through the system. The system includes a discharge line for receiving the dusty gas from the hopper, a valve, a cascade nozzle assembly positioned downstream of the discharge line, a purge ring, an inert gas supply connected to the purge ring, an inert gas throttle, and a filter. The valve connects the hopper to the discharge line and controls introduction of the dusty gas stream into the discharge line. The purge ring is connected between the discharge line and the cascade nozzle assembly. The inert gas throttle controls a flow rate of an inert gas into the cascade nozzle assembly. The filter is connected downstream of the cascade nozzle assembly.

  14. High Pressure Atomization.

    DTIC Science & Technology

    1982-03-01

    water and tetradecane (factor of 10 in viscosity, 4 in surface ten- sion, 1.5 in liquid density); Pentane, hexane, and ethanol (factor of 3 surface...be of the order of centimeters and sensitive to conditions. In particular it * decreases with increasing injection pressure, gas temperature, and gas...nozzle inlet and with decreasing smaller than the jet diameter are formed. The liquid viscosity and nozzle length; divergence mechanism of Atomization

  15. 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.

  16. Dynamic Pressure Microphones

    NASA Astrophysics Data System (ADS)

    Werner, E.

    In 1876, Alexander Graham Bell described his first telephone with a microphone using magnetic induction to convert the voice input into an electric output signal. The basic principle led to a variety of designs optimized for different needs, from hearing impaired users to singers or broadcast announcers. From the various sound pressure versions, only the moving coil design is still in mass production for speech and music application.

  17. Low-pressure

    SciTech Connect

    Baker, Richard; Kniep, Jay; Hao, Pingjiao; Chan, Chi Cheng; Nguyen, Vincent; Huang, Ivy; Amo, Karl; Freeman, Brice; Fulton, Don; Ly, Jennifer; Lipscomb, Glenn; Lou, Yuecun; Gogar, Ravikumar

    2015-01-29

    This final technical progress report describes work conducted by Membrane Technology and Research, Inc. (MTR) for the Department of Energy (DOE NETL) on development of low-pressure membrane contactors for carbon dioxide (CO2) capture from power plant flue gas (award number DE-FE0007553). The work was conducted from October 1, 2011 through September 30, 2014. The overall goal of this three-year project was to build and operate a prototype 500 m2 low-pressure sweep membrane module specifically designed to separate CO2 from coal-fired power plant flue gas. MTR was assisted in this project by a research group at the University of Toledo, which contributed to the computational fluid dynamics (CFD) analysis of module design and process simulation. This report details the work conducted to develop a new type of membrane contactor specifically designed for the high-gas-flow, low-pressure, countercurrent sweep operation required for affordable membrane-based CO2 capture at coal power plants. Work for this project included module development and testing, design and assembly of a large membrane module test unit at MTR, CFD comparative analysis of cross-flow, countercurrent, and novel partial-countercurrent sweep membrane module designs, CFD analysis of membrane spacers, design and fabrication of a 500 m2 membrane module skid for field tests, a detailed performance and cost analysis of the MTR CO2 capture process with low-pressure sweep modules, and a process design analysis of a membrane-hybrid separation process for CO2 removal from coal-fired flue gas. Key results for each major task are discussed in the report.

  18. NASA Super Pressure Balloon

    NASA Technical Reports Server (NTRS)

    Fairbrother, Debbie

    2016-01-01

    NASA is in the process of qualifying the mid-size Super Pressure Balloon (SPB) to provide constant density altitude flight for science investigations at polar and mid-latitudes. The status of the development of the 18.8 million cubic foot SPB capable of carrying one-tonne of science to 110,000 feet, will be given. In addition, the operating considerations such as launch sites, flight safety considerations, and recovery will be discussed.

  19. DEFLECTION PRESSURE TESTER

    DOEpatents

    Cooper, C.M.

    1961-01-01

    A method and apparatus for determining whether the jacket of a nuclear- fuel slug has a leak are described. The region of the jacket to be leak-tested is sealed off, and gas under pressure is applied thereto. If there is an imperfection, the gas will enter the jacket and bulge another region of the jacket. The bulge occurring is measured by a gage.

  20. 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.

  1. Pressurized Submarine Rescue

    DTIC Science & Technology

    1984-06-07

    The atmosphere components can be divided into nitrogen , oxygen, carbon dioxide and contaminates. i. Nitrogen . Nitrogen causes narcosis in a dose...compared with 80% helium 20% oxygen. The narcosis increases as the pressure increases to where debilitation occurs above about 8 ATA (9.3 ATA nitrogen ...when breathing air. Nitrogen narcosis is relatively mild at 5 ATA, and although decrements in performance can be measured in a laboratory setting (19

  2. Pressure Controlled Chemical Gardens.

    PubMed

    Bentley, Megan R; Batista, Bruno C; Steinbock, Oliver

    2016-06-30

    The dissolution of metal salts in silicate solution can result in the growth of hollow precipitate tubes. These "chemical gardens" are a model of self-organization far from the equilibrium and create permanent macroscopic structures. The reproducibility of the growth process is greatly improved if the solid salt seed is replaced by a salt solution that is steadily injected by a pump; however, this modification of the original experiment eliminates the membrane-based osmotic pump at the base of conventional chemical gardens and does not allow for analyses in terms of the involved pressure. Here we describe a new experimental method that delivers the salt solution according to a controlled hydrostatic pressure. In one form of the experiment, this pressure slowly decreases as zinc sulfate solution flows into the silicate-containing reaction vessel, whereas a second version holds the respective solution heights constant. In addition to three known growth regimes (jetting, popping, budding), we observe single tubes that fill the vessel in a horizontally undulating but vertically layered fashion (crowding). The resulting, dried product has a cylindrical shape, very low density, and one continuous connection from top to bottom. We also present phase diagrams of these growth modes and show that the flow characteristics of our experiments follow a reaction-independent Hagen-Poiseuille equation.

  3. 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

  4. Intracranial pressure monitoring system with pneumatic capsule sensor

    NASA Astrophysics Data System (ADS)

    Juniewicz, Henryk M.; Werszko, Miroslaw

    1995-06-01

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

  5. Pressure-Application Device for Testing Pressure Sensors

    NASA Technical Reports Server (NTRS)

    2002-01-01

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

  6. Pressure garment design tool to monitor exerted pressures.

    PubMed

    Macintyre, Lisa; Ferguson, Rhona

    2013-09-01

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

  7. A control system for maintaining high stability in gas pressure

    SciTech Connect

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

    1987-09-01

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

  8. Simulation of turbulent wall pressure

    NASA Technical Reports Server (NTRS)

    Ash, R. L.

    1976-01-01

    A computer program has been developed to simulate the transient wall pressure field produced by a low speed fully turbulent boundary layer. The theoretical basis for the simulation has been discussed and preliminary results from a pressure simulation are presented.

  9. 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 ...

  10. What Causes High Blood Pressure?

    MedlinePlus

    ... the NHLBI on Twitter. Causes of High Blood Pressure Changes, either from genes or the environment, in ... vessel structure and function. Biology and High Blood Pressure Researchers continue to study how various changes in ...

  11. Blood Pressure vs. Heart Rate

    MedlinePlus

    ... Artery Disease Venous Thromboembolism Aortic Aneurysm More Blood Pressure vs. Heart Rate (Pulse) Updated:Jan 18,2017 ... content was last reviewed October 2016. High Blood Pressure • Home • Get the Facts About HBP Introduction What ...

  12. Stroke and High Blood Pressure

    MedlinePlus

    ... Venous Thromboembolism Aortic Aneurysm More How High Blood Pressure Can Lead to Stroke Updated:Dec 2,2016 ... content was last reviewed October 2016. High Blood Pressure • Home • Get the Facts About HBP • Know Your ...

  13. Common High Blood Pressure Myths

    MedlinePlus

    ... Venous Thromboembolism Aortic Aneurysm More Common High Blood Pressure Myths Updated:Apr 7,2017 Knowing the facts ... content was last reviewed October 2016. High Blood Pressure • Home • Get the Facts About HBP Introduction What ...

  14. 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 ...

  15. 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.

  16. Diagnosis of High Blood Pressure

    MedlinePlus Videos and Cool Tools

    ... above. Confirming High Blood Pressure A blood pressure test is easy and painless and can be done ... provider’s office or clinic. To prepare for the test: Don’t drink coffee or smoke cigarettes for ...

  17. Measuring pressure under burns pressure garments using the Oxford Pressure Monitor.

    PubMed

    Harries, C A; Pegg, S P

    1989-06-01

    Pressure garments are used extensively in the treatment of hypertrophic scarring following burn injuries. The Oxford Pressure Monitor was used to measure garment-scar interface pressure (mmHg) using a number of fabric types over various body parts. The results indicate a wide range of pressure values between different garments and body parts with the greatest pressures found over the dorsum of hands and feet. The problems of achieving 'optimal pressure' over hypertrophic scarring are discussed with emphasis on the need for more accurate measuring equipment.

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

    NASA Astrophysics Data System (ADS)

    Saccomandi, Paola; Schena, Emiliano; Silvestri, Sergio

    2011-02-01

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

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

    SciTech Connect

    Saccomandi, Paola; Schena, Emiliano; Silvestri, Sergio

    2011-02-15

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

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

    PubMed

    Saccomandi, Paola; Schena, Emiliano; Silvestri, Sergio

    2011-02-01

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

  1. 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.

  2. 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).

  3. The jugular venous pressure revisited

    PubMed Central

    CHIACO, JOHN MICHAEL S. CHUA; PARIKH, NISHA I.; FERGUSSON, DAVID J.

    2016-01-01

    Assessment of the jugular venous pressure is often inadequately performed and undervalued. Here, we review the physiologic and anatomic basis for the jugular venous pressure, including the discrepancy between right atrial and central venous pressures. We also describe the correct method of evaluating this clinical finding and review the clinical relevance of the jugular venous pressure, especially its value in assessing the severity and response to treatment of congestive heart failure. Waveforms reflective of specific conditions are also discussed. PMID:24085809

  4. HIGH PRESSURE DIES

    DOEpatents

    Wilson, W.B.

    1960-05-31

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

  5. Vapor Pressure of GB

    DTIC Science & Technology

    2009-04-01

    EDGEWOOD CHEMICAL BIOLOGICAL CENTER U.S. ARMY RESEARCH, DEVELOPMENT AND ENGINEERING COMMAND ECBC-TR-686 VAPOR PRESSURE OF GB James H. Buchanan...275 °C under a flow rate of 20 seem UHP -grade helium for 5 min and transferred to the ACEM 900 tenax focusing trap maintained at 40 °C. Transfer...a flow rate of 8.0 seem UHP grade helium for 5 min to affect sample transfer to the gas chromatographic column. The 15 m x 0.53 mm i.d. fused silica

  6. 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.

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

    NASA Technical Reports Server (NTRS)

    Iida, H.; Uemura, M.

    1987-01-01

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

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

    SciTech Connect

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

    1980-02-01

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

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

    NASA Astrophysics Data System (ADS)

    Giovanangeli, J. P.; Chambaud, P.

    1987-07-01

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

  10. The Myth of Peer Pressure.

    ERIC Educational Resources Information Center

    Ungar, Michael T.

    2000-01-01

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

  11. Pressure Safety: Advanced Live 11459

    SciTech Connect

    Glass, George

    2016-03-02

    Many Los Alamos National Laboratory (LANL) operations use pressure equipment and systems. Failure to follow proper procedures when designing or operating pressure systems can result in injuries to personnel and damage to equipment and/or the environment. This manual presents an overview of the requirements and recommendations that address the safe design and operation of pressure systems at LANL.

  12. 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.

  13. Gas Pressure-Drop Experiment

    ERIC Educational Resources Information Center

    Luyben, William L.; Tuzla, Kemal

    2010-01-01

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

  14. 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.

  15. 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.

  16. High pressure studies of potassium perchlorate

    SciTech Connect

    Pravica, Michael; Wang, Yonggang; Sneed, Daniel; Reiser, Sharissa; White, Melanie

    2016-07-29

    Two experiments are reported on KClO4 at extreme conditions. A static high pressure Raman study was first conducted to 18.9 GPa. Evidence for at least two new phases was observed: one between 2.4 and 7.7 GPa (possibly sluggish), and the second near 11.7 GPa. Then, the X-ray induced decomposition rate of potassium perchlorate (KClO4 hv→ KCl + 2O2) was studied up to 15.2 GPa. The time-dependent growth of KCl and O2 was monitored. The decomposition rate slowed at higher pressures. As a result, we present the first direct evidence for O2 crystallization at higher pressures, demonstrating that O2 molecules aggregate at high pressure.

  17. Pressure-confined Lyman-alpha clouds

    SciTech Connect

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

    1989-02-01

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

  18. An instrument for measuring turbulent pressure fluctuations

    NASA Astrophysics Data System (ADS)

    Papadimitrakis, Yiannis Alex; Hsu, En Yu; Street, Robert L.

    1986-04-01

    An instrument is described for laboratory measurements of the fluctuating static pressure in the turbulent boundary layer above progressive water waves. It consists of a disk-shaped sensing head properly designed to minimize the dynamic pressure variation to an acceptable level, a commercially available piezocrystal transducer housed inside a casing, and a forward-bent connecting tube. Pressure fluctuations sampled by the disk are converted into an electrical signal by the piezocrystal transducer. Through low-pass filtering, only the frequency range of interest is retained. The instrument was tested successfully for frequency response, dynamic and mechanical noise sensitivity, and response to spurious pressure fluctuations (produced when operating in a Eulerian wave-following mode) inside a cylindrical chamber and in a wind-wave facility, and some sample results along with the calibration procedures and data analysis are presented.

  19. High pressure studies of potassium perchlorate

    DOE PAGES

    Pravica, Michael; Wang, Yonggang; Sneed, Daniel; ...

    2016-07-29

    Two experiments are reported on KClO4 at extreme conditions. A static high pressure Raman study was first conducted to 18.9 GPa. Evidence for at least two new phases was observed: one between 2.4 and 7.7 GPa (possibly sluggish), and the second near 11.7 GPa. Then, the X-ray induced decomposition rate of potassium perchlorate (KClO4 hv→ KCl + 2O2) was studied up to 15.2 GPa. The time-dependent growth of KCl and O2 was monitored. The decomposition rate slowed at higher pressures. As a result, we present the first direct evidence for O2 crystallization at higher pressures, demonstrating that O2 molecules aggregatemore » at high pressure.« less

  20. Pressure polymerization of polyester

    DOEpatents

    Maurer, Charles J.; Shaw, Gordon; Smith, Vicky S.; Buelow, Steven J.; Tumas, William; Contreras, Veronica; Martinez, Ronald J.

    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.

  1. 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.

  2. 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.

  3. Negative Pressure Wound Therapy

    PubMed Central

    2006-01-01

    Executive Summary Objective This review was conducted to assess the effectiveness of negative pressure wound therapy. Clinical Need: Target Population and Condition Many wounds are difficult to heal, despite medical and nursing care. They may result from complications of an underlying disease, like diabetes; or from surgery, constant pressure, trauma, or burns. Chronic wounds are more often found in elderly people and in those with immunologic or chronic diseases. Chronic wounds may lead to impaired quality of life and functioning, to amputation, or even to death. The prevalence of chronic ulcers is difficult to ascertain. It varies by condition and complications due to the condition that caused the ulcer. There are, however, some data on condition-specific prevalence rates; for example, of patients with diabetes, 15% are thought to have foot ulcers at some time during their lives. The approximate community care cost of treating leg ulcers in Canada, without reference to cause, has been estimated at upward of $100 million per year. Surgically created wounds can also become chronic, especially if they become infected. For example, the reported incidence of sternal wound infections after median sternotomy is 1% to 5%. Abdominal surgery also creates large open wounds. Because it is sometimes necessary to leave these wounds open and allow them to heal on their own (secondary intention), some may become infected and be difficult to heal. Yet, little is known about the wound healing process, and this makes treating wounds challenging. Many types of interventions are used to treat wounds. Current best practice for the treatment of ulcers and other chronic wounds includes debridement (the removal of dead or contaminated tissue), which can be surgical, mechanical, or chemical; bacterial balance; and moisture balance. Treating the cause, ensuring good nutrition, and preventing primary infection also help wounds to heal. Saline or wet-to-moist dressings are reported as

  4. High-pressure neutron diffraction

    SciTech Connect

    Xu, Hongwu

    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.

  5. Assessment of fiber optic pressure sensors

    SciTech Connect

    Hashemian, H.M.; Black, C.L.; Farmer, J.P.

    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.

  6. The transmission of gas pressure to xylem fluid pressure when plants are inside a pressure bomb.

    PubMed

    Wei, C; Tyree, M T; Bennink, J P

    2000-02-01

    In earlier work tobacco leaves were placed in a Scholander-Hammel pressure bomb and the end of the petiole sealed with a pressure transducer in order to measure pressure transmission from the compressed gas (Pg) in the bomb to the xylem fluid (Px). Pressure bomb theory would predict a 1:1 relationship for Pg:Px when tobacco leaves start at a balance pressure of zero. Failure to observe the expected 1:1 relationship has cast doubt on the pressure-bomb technique in the measurement of the xylem pressure of plants. The experimental and theoretical relationship between Px and Pg was investigated in Tsuga canadensis (L) branches and Nicotiana rustica (L) leaves in this paper. It is concluded that the non 1:1 outcome was due to the compression of air bubbles in embolized xylem vessels, evaporation of water from the tissue, and the expansion of the sealed stem segment (or petiole) protruding beyond the seal of the pressure bomb. The expected 1:1 relationship could be obtained when xylem embolism was eliminated and stem expansion prevented. It is argued that the non 1:1 relationship in the positive pressure range does not invalidate the Scholander pressure bomb method of measuring xylem pressure in plants because Px never reaches positive values during the determination of the balance pressure.

  7. 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.

  8. 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.

  9. Designing pressure garments capable of exerting specific pressures on limbs.

    PubMed

    Macintyre, Lisa

    2007-08-01

    Pressure garments have been used prophylactically and to treat hypertrophic scars, resulting from serious burns, since the early 1970s. They are custom-made from elastic fabrics by commercial producers and hospital staff. However, no clear scientifically established method has ever been published for their design and manufacture. Previous work [2] identified the most commonly used fabrics and construction methods for the production of pressure garments by hospital staff in UK burn units. These methods were evaluated by measuring pressures delivered to both cylinder models and to human limbs using I-scan pressure sensors. A new calibration method was developed for the I-scan system to enable measurement of low interface pressures to an accuracy of +/-2.5 mmHg. The effects of cylinder/limb circumference and pressure garment design on the pressures exerted were established. These measurements confirm the limitations of current pressure garment construction methods used in UK hospitals. A new method for designing pressure garments that will exert specific known pressures is proposed and evaluated for human thighs. Evaluation of the proposed design method is ongoing for other body parts.

  10. 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.

  11. 49 CFR 195.304 - Test pressure.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 3 2014-10-01 2014-10-01 false Test pressure. 195.304 Section 195.304... PIPELINE Pressure Testing § 195.304 Test pressure. The test pressure for each pressure test conducted under... continuous hours at a pressure equal to 125 percent, or more, of the maximum operating pressure and, in...

  12. 49 CFR 195.304 - Test pressure.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 3 2010-10-01 2010-10-01 false Test pressure. 195.304 Section 195.304... PIPELINE Pressure Testing § 195.304 Test pressure. The test pressure for each pressure test conducted under... continuous hours at a pressure equal to 125 percent, or more, of the maximum operating pressure and, in...

  13. 49 CFR 195.304 - Test pressure.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 3 2011-10-01 2011-10-01 false Test pressure. 195.304 Section 195.304... PIPELINE Pressure Testing § 195.304 Test pressure. The test pressure for each pressure test conducted under... continuous hours at a pressure equal to 125 percent, or more, of the maximum operating pressure and, in...

  14. 49 CFR 195.304 - Test pressure.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 3 2012-10-01 2012-10-01 false Test pressure. 195.304 Section 195.304... PIPELINE Pressure Testing § 195.304 Test pressure. The test pressure for each pressure test conducted under... continuous hours at a pressure equal to 125 percent, or more, of the maximum operating pressure and, in...

  15. Sensors, transducers, and systems for blood pressure and intracranial pressure monitoring

    NASA Astrophysics Data System (ADS)

    Juniewicz, Henryk M.; Kedryna, Zbigniew M.

    1997-02-01

    An overview of commercial sensors, transducers, monitors and computer systems for arterial pressure and intracranial pressure monitoring has been made in this paper. Similar technical specifications of the devices (measurement range, sensitivity, accuracy) have been emphasized, as well as a variety of structural solutions influencing their static and dynamic parameters. A computer based test stand for checking dynamic properties of pneumatic pressure transducers is presented. It enables tests in a full range of amplitude and frequency change, visualization and comparative analysis of sensor responses for various supply conditions. Exemplary waveforms are shown and initial conclusions concerning sensor features are drawn.

  16. 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.

  17. Pressure vessel bottle mount

    NASA Technical Reports Server (NTRS)

    Wingett, Paul (Inventor)

    2001-01-01

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

  18. 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.

  19. High pressure mechanical seal

    NASA Technical Reports Server (NTRS)

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

    1995-01-01

    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, prior to swaging the fitting onto the tube. The thickness of such thin metal layer is independent of the size of the tube and/or fittings. Many metals and alloys of those metals exhibit the requisite softness, including silver, gold, nickel, tin, platinum, indium, rhodium and cadmium. Suitably, the coating is about 0.0025 millimeters (0.10 mils) in thickness. After swaging, the tube and fitting combination exhibits very low leak rates on the order or 10.sup.-8 cubic centimeters per second or less as meaured using the Helium leak test.

  20. 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.

  1. A Constant Pressure Bomb

    NASA Technical Reports Server (NTRS)

    Stevens, F W

    1924-01-01

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

  2. Cradle and pressure grippers

    DOEpatents

    Muniak, John E.

    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.

  3. Pressure vessel design manual

    SciTech Connect

    Moss, D.R.

    1987-01-01

    The first section of the book covers types of loadings, failures, and stress theories, and how they apply to pressure vessels. The book delineates the procedures for designing typical components as well as those for designing large openings in cylindrical shells, ring girders, davits, platforms, bins and elevated tanks. The techniques for designing conical transitions, cone-cylinder intersections, intermediate heads, flat heads, and spherically dished covers are also described. The book covers the design of vessel supports subject to wind and seismic loads and one section is devoted to the five major ways of analyzing loads on shells and heads. Each procedure is detailed enough to size all welds, bolts, and plate thicknesses and to determine actual stresses.

  4. BWR zero pressure containment

    SciTech Connect

    Dillmann, C.W.; Townsend, H.E.; Nesbitt, L.B.

    1992-02-25

    This patent describes the operation of a nuclear reactor system, the system including a containment defining a drywall space wherein a nuclear reactor is disposed, there being a suppression pool in the containment with the suppression pool having a wetwell space above a level of the pool to which an non-condensable gases entering the suppression pool can vent. It comprises: continuously exhausting the wetwell space to remove gas mixture therefrom while admitting inflow of air from an atmospheric source thereof to the wetwell during normal operation by blocking off the inflow during a loss-of-coolant-accident whenever a pressure in the wetwell space is above a predetermined value, and subjecting the gas subsequent to its removal from the wetwell to a treatment operation to separate any particulate material entrained therein from the gas mixture.

  5. High-pressure cryogenic seals for pressure vessels

    NASA Technical Reports Server (NTRS)

    Buggele, A. E.

    1977-01-01

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

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

    SciTech Connect

    Spivak, A.V.; Litvin, Yu.A.; Ovsyannikov, S.V.; Dubrovinskaia, N.A.; Dubrovinsky, L.S.

    2012-07-15

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

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

    NASA Astrophysics Data System (ADS)

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

    2003-03-01

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

  8. Collapse pressure of coiled tubing

    SciTech Connect

    Yang, Y.S.

    1996-09-01

    The collapse pressure is a measure of an external force required to collapse a tube in the absence of internal pressure. It is defined as the minimum pressure required to yield the tube in the absence of internal pressure. Coiled tubing is sometimes used in high-pressure wells. If the external pressure becomes too high, the coiled tubing will collapse. This could not only lead to serious well-control problems, but may result in extensive fishing operations. A reliable safety criterion of collapse pressure for the coiled tubing is needed by the coiled tubing operators. Theoretical models of collapse pressure are well developed for perfectly round coiled tubing but not for oval coiled tubing. Coiled tubing is initially manufactured with nearly perfect roundness, sometimes having a small ovality (typically {le} 0.5%). Perfectly round CT becomes oval owing to the plastic mechanical deformation of the coiled tubing as it spooled on and off the reel and over the gooseneck. As the cycling continues, the ovality usually increases. This ovality significantly decreases the collapse failure pressure as compared to perfectly round tubing. In this paper, an analytical model of collapse pressure for oval tubing under axial tension or compression is developed based on elastic instability theory and the von Mises criterion. The theoretical model shows satisfactory agreement with experimental data.

  9. Blood pressure regulation: basic concepts.

    PubMed

    Guyton, A C; Hall, J E; Lohmeier, T E; Jackson, T E; Kastner, P R

    1981-06-01

    In this paper we have attempted to explain the difference between proportional pressure control systems and the renal-blood volume-pressure control mechanism, which is an infinite gain pressure control system. Because of this infinite gain of the kidney mechanism, this mechanism has the capability of returning arterial pressure all the way back to the control leve. Furthermore, this mechanism can override the other pressure control mechanisms because of its extreme control capability. On the other hand, the renal-blood volume mechanism for pressure control itself be controlled by many other factors. These other factors are said to change the pressure "set-point" level of the renal system, and then the renal system automatically brings the pressure to the set-point level. It is especially noteworthy, however, that some of the factors that play extreme roles in short-term pressure control-such as heart strength, vascular capacity, and total peripheral resistance-will not alter the long-term arterial pressure level (unless they in some way concurrently alter the set-point of the kidney mechanism).

  10. Pressure Inactivation of Bacillus Endospores

    PubMed Central

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

    2004-01-01

    The inactivation of bacterial endospores by hydrostatic pressure requires the combined application of heat and pressure. We have determined the resistance of spores of 14 food isolates and 5 laboratory strains of Bacillus subtilis, B. amyloliquefaciens, and B. licheniformis to treatments with pressure and temperature (200 to 800 MPa and 60 to 80°C) in mashed carrots. A large variation in the pressure resistance of spores was observed, and their reduction by treatments with 800 MPa and 70°C for 4 min ranged from more than 6 log units to no reduction. The sporulation conditions further influenced their pressure resistance. The loss of dipicolinic acid (DPA) from spores that varied in their pressure resistance was determined, and spore sublethal injury was assessed by determination of the detection times for individual spores. Treatment of spores with pressure and temperature resulted in DPA-free, phase-bright spores. These spores were sensitive to moderate heat and exhibited strongly increased detection times as judged by the time required for single spores to grow to visible turbidity of the growth medium. The role of DPA in heat and pressure resistance was further substantiated by the use of the DPA-deficient mutant strain B. subtilis CIP 76.26. Taken together, these results indicate that inactivation of spores by combined pressure and temperature processing is achieved by a two-stage mechanism that does not involve germination. At a pressure between 600 and 800 MPa and a temperature greater than 60°C, DPA is released predominantly by a physicochemical rather than a physiological process, and the DPA-free spores are inactivated by moderate heat independent of the pressure level. Relevant target organisms for pressure and temperature treatment of foods are proposed, namely, strains of B. amyloliquefaciens, which form highly pressure-resistant spores. PMID:15574932

  11. Regulation of arterial pressure: role of pressure natriuresis and diuresis.

    PubMed

    Hall, J E; Guyton, A C; Coleman, T G; Mizelle, H L; Woods, L L

    1986-12-01

    The importance of the renal pressure natriuresis and diuresis mechanisms in long-term control of body fluid volumes and arterial pressure has been controversial and difficult to quantitate experimentally. Recent studies, however, have demonstrated that in several forms of chronic hypertension caused by aldosterone, angiotensin II (AngII), vasopressin, or norepinephrine and adrenocorticotropin, increased renal arterial pressure is essential for maintaining normal excretion of sodium and water in the face of reduced renal excretory capability. When renal arterial pressure was servo-controlled in these models of hypertension, sodium and water retention continued unabated, causing ascites, pulmonary edema, or even complete circulatory collapse within a few days. Apparently, other mechanisms for volume homeostasis, such as the various natriuretic and diuretic factors that have been postulated, are not sufficiently powerful to maintain fluid balance in the absence of increased renal arterial pressure when renal excretory function is reduced in these forms of hypertension. The intrarenal mechanisms responsible for pressure natriuresis and diuresis are not entirely clear, but they seem to involve small increases in glomerular filtration rate and filtered load as well as reductions in fractional reabsorption in proximal and distal tubules. During chronic disturbances of arterial pressure additional factors, especially changes in AngII and aldosterone formation, act to amplify the effectiveness of the basic renal pressure natriuresis and diuresis mechanisms in regulating arterial pressure and body fluid volumes.

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

    SciTech Connect

    Christoffersen, K.R.; Whitson, C.H.

    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.

  13. 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

    ... test; Type C supplied-air respirator, pressure-demand class; minimum requirements. (a) The static...) per minute shall not exceed the static pressure in the facepiece by more than 51 mm. (2 inches)...

  14. Multilayer Composite Pressure Vessels

    NASA Technical Reports Server (NTRS)

    DeLay, Tom

    2005-01-01

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

  15. Steam Oxidation at High Pressure

    SciTech Connect

    Holcomb, Gordon R.; Carney, Casey

    2013-07-19

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

  16. [High Pressure Gas Tanks

    NASA Technical Reports Server (NTRS)

    Quintana, Rolando

    2002-01-01

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

  17. 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

  18. A pressurized gas squeeze film journal damper

    NASA Technical Reports Server (NTRS)

    Stiffler, A. K.

    1977-01-01

    A lumped parameter model is developed to determine the stiffness and damping characteristics of inherently compensated gas film bearings. The model relies on the average static pressure over a one dimensional strip bearing. Results of the model are compared with known computer solutions for the distributed strip and a two dimensional square bearing. The results for the stiffness agree well with the computer solutions although the model proved to be inadequate for predicting the film damping.

  19. Bidirectional Pressure-Regulator System

    NASA Technical Reports Server (NTRS)

    Burke, Kenneth; Miller, John R.

    2008-01-01

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

  20. Nanomaterials under high-pressure.

    PubMed

    San-Miguel, Alfonso

    2006-10-01

    The use of high-pressure for the study and elaboration of homogeneous nanostructures is critically reviewed. Size effects, the interaction between nanostructures and guest species or the interaction of the nanosystem with the pressure transmitting medium are emphasized. Phase diagrams and the possibilities opened by the combination of pressure and temperature for the elaboration of new nanomaterials is underlined through the examination of three different systems: nanocrystals, nano-cage materials which include fullerites and group-14 clathrates, and single wall nanotubes. This tutorial review is addressed to scientist seeking an introduction or a panoramic view of the study of nanomaterials under high-pressure.

  1. Nutrition systems for pressure suits.

    NASA Technical Reports Server (NTRS)

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

    1973-01-01

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

  2. 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.

  3. High pressure synthesis gas fermentation

    SciTech Connect

    Not Available

    1991-01-01

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

  4. 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.

  5. Pressure differential plunger

    SciTech Connect

    Baggett, J.W.

    1987-08-11

    A plunger is described for use in the pump barrel of a downhole pump comprising: a substantially cylindrical body having a central longitudinal bore terminating at its upper end in a valve chamber and at its lower end in a venturi throat to enhance the rapid entry of well fluid into the bore; a valve seat located at the upper end of the bore facing toward the valve chamber and having an opening therethrough of less diameter than the bore; a valve element vertically reciprocable in the valve chamber, and adapted to seat on the valve seat upon an upward stroke of the cylindrical body in the pump barrel; the valve chamber having a cross-sectional area sufficiently larger than the cross-sectional area of the bore to substantially reduce pressure build-up above the valve element upon downward movement of the cylindrical body within the pump barrel; and the cylindrical body configured to be slidably fitted within the pump barrel such that the seal provided by the slidably fitting metal surfaces of the cylindrical body and the pump barrel are positioned between the valve element and the lower end of the bore.

  6. 33 CFR 183.586 - Pressure impulse test.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... prior to testing. (c) Mount the tank on a test platform. (d) Fill the tank to capacity with water. (e) Cap and seal each opening in the tank. (f) Apply 25,000 cycles of pressure impulse at the rate of no... regulated source of air, inert gas, or water. (g) Perform the static pressure test under § 183.580....

  7. 33 CFR 183.586 - Pressure impulse test.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... prior to testing. (c) Mount the tank on a test platform. (d) Fill the tank to capacity with water. (e) Cap and seal each opening in the tank. (f) Apply 25,000 cycles of pressure impulse at the rate of no... regulated source of air, inert gas, or water. (g) Perform the static pressure test under § 183.580....

  8. 33 CFR 183.586 - Pressure impulse test.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... prior to testing. (c) Mount the tank on a test platform. (d) Fill the tank to capacity with water. (e) Cap and seal each opening in the tank. (f) Apply 25,000 cycles of pressure impulse at the rate of no... regulated source of air, inert gas, or water. (g) Perform the static pressure test under § 183.580....

  9. 33 CFR 183.586 - Pressure impulse test.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... prior to testing. (c) Mount the tank on a test platform. (d) Fill the tank to capacity with water. (e) Cap and seal each opening in the tank. (f) Apply 25,000 cycles of pressure impulse at the rate of no... regulated source of air, inert gas, or water. (g) Perform the static pressure test under § 183.580....

  10. 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.

  11. 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.

  12. Magnetic and Superconducting Materials at High Pressures

    SciTech Connect

    Struzhkin, Viktor V.

    2015-03-24

    The work concentrates on few important tasks in enabling techniques for search of superconducting compressed hydrogen compounds and pure hydrogen, investigation of mechanisms of high-Tc superconductivity, and exploring new superconducting materials. Along that route we performed several challenging tasks, including discovery of new forms of polyhydrides of alkali metal Na at very high pressures. These experiments help us to establish the experimental environment that will provide important information on the high-pressure properties of hydrogen-rich compounds. Our recent progress in RIXS measurements opens a whole field of strongly correlated 3d materials. We have developed a systematic approach to measure major electronic parameters, like Hubbard energy U, and charge transfer energy Δ, as function of pressure. This technique will enable also RIXS studies of magnetic excitations in iridates and other 5d materials at the L edge, which attract a lot of interest recently. We have developed new magnetic sensing technique based on optically detected magnetic resonance from NV centers in diamond. The technique can be applied to study superconductivity in high-TC materials, to search for magnetic transitions in strongly correlated and itinerant magnetic materials under pressure. Summary of Project Activities; development of high-pressure experimentation platform for exploration of new potential superconductors, metal polyhydrides (including newly discovered alkali metal polyhydrides), and already known superconductors at the limit of static high-pressure techniques; investigation of special classes of superconducting compounds (high-Tc superconductors, new superconducting materials), that may provide new fundamental knowledge and may prove important for application as high-temperature/high-critical parameter superconductors; investigation of the pressure dependence of superconductivity and magnetic/phase transformations in 3d transition metal compounds, including

  13. 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

  14. 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

  15. Coasts under pressure.

    PubMed

    Hinrichsen, D

    1994-01-01

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

  16. Kids, Clothes and Peer Pressure.

    ERIC Educational Resources Information Center

    Rosenberg, Ellen

    1989-01-01

    Parents are advised on ways to cope with the peer pressure associated with clothes. Techniques focus on countering and preventing peer pressure or, at least, putting it into healthier perspective. A list of retorts children can make to peer critics is included. (IAH)

  17. Drinking pattern and blood pressure.

    PubMed

    Seppä, K; Laippala, P; Sillanaukee, P

    1994-03-01

    Large amounts of alcohol are known to increase blood pressure. There is little evidence about the effect of binge drinking of alcohol on blood pressure, although this is the dominant style of alcohol drinking in several countries. The purpose of the present study was to examine the relationship between binge drinking and blood pressure using daily heavy drinkers as a reference group. We examined 260 consecutive nonalcoholic 40- and 45-year-old men participating in a health screening. There were 37 teetotalers, 147 social drinkers, 62 weekend heavy drinkers attending the health screening 2 to 7 days after binge drinking, and 14 men who drank heavily every day. Group division was made using self-reported alcohol consumption and a structured alcohol questionnaire. Blood pressure was measured manually by a mercury manometer. BMDP statistical software was used in the statistical analysis of the material. The diastolic blood pressure of weekend heavy drinkers (mean intake during the weekend, 289 g) did not differ from that found in teetotalers but systolic blood pressure was slightly higher (5 mm Hg, P = .04). In contrast, daily heavy drinkers (mean intake during the weekend [Friday to Saturday], 151 g) had significantly higher systolic (8 mm Hg, P = .04) and diastolic (6 mm Hg, P = .05) blood pressure values than teetotalers. We conclude that different drinking habits seem to have different effects on blood pressure, those of daily heavy drinking being more prominent than those of weekend heavy drinking.

  18. 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.

  19. Microwave Atmospheric-Pressure Sensor

    NASA Technical Reports Server (NTRS)

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

    1986-01-01

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

  20. Magnetospheric equilibrium with anisotropic pressure

    SciTech Connect

    Cheng, C.Z.

    1991-07-01

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

  1. Electrokinetically pumped high pressure sprays

    DOEpatents

    Schoeniger, Joseph S.; Paul, Phillip H.; Schoeniger, Luke

    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.

  2. Electrokinetically pumped high pressure sprays

    DOEpatents

    Schoeniger, Joseph S.; Paul, Phillip H.; Schoeniger, Luke

    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.

  3. 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 ...

  4. High Blood Pressure Increasing Worldwide

    MedlinePlus

    ... other ways to control blood pressure, including healthy lifestyle choices and maintaining a normal weight, Roth said. Murray said some of the factors responsible for the worldwide increase in high blood pressure are unhealthy diets and obesity. In addition, in developing countries, more people are ...

  5. Pressure Reducer for Coal Gasifiers

    NASA Technical Reports Server (NTRS)

    Kendall, James M., Sr.

    1983-01-01

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

  6. Balanced pressure gerotor fuel pump

    DOEpatents

    Raney, Michael Raymond; Maier, Eugen

    2004-08-03

    A gerotor pump for pressurizing gasoline fuel is capable of developing pressures up to 2.0 MPa with good mechanical and volumetric efficiency and satisfying the durability requirements for an automotive fuel pump. The pump has been designed with optimized clearances and by including features that promote the formation of lubricating films of pressurized fuel. Features of the improved pump include the use of a shadow port in the side plate opposite the outlet port to promote balancing of high fuel pressures on the opposite sides of the rotors. Inner and outer rotors have predetermined side clearances with the clearances of the outer rotor being greater than those of the inner rotor in order to promote fuel pressure balance on the sides of the outer rotor. Support of the inner rotor and a drive shaft on a single bushing with bearing sleeves maintains concentricity. Additional features are disclosed.

  7. Piezoelectric enhancement under negative pressure

    PubMed Central

    Kvasov, Alexander; McGilly, Leo J.; Wang, Jin; Shi, Zhiyong; Sandu, Cosmin S.; Sluka, Tomas; Tagantsev, Alexander K.; Setter, Nava

    2016-01-01

    Enhancement of ferroelectric properties, both spontaneous polarization and Curie temperature under negative pressure had been predicted in the past from first principles and recently confirmed experimentally. In contrast, piezoelectric properties are expected to increase by positive pressure, through polarization rotation. Here we investigate the piezoelectric response of the classical PbTiO3, Pb(Zr,Ti)O3 and BaTiO3 perovskite ferroelectrics under negative pressure from first principles and find significant enhancement. Piezoelectric response is then tested experimentally on free-standing PbTiO3 and Pb(Zr,Ti)O3 nanowires under self-sustained negative pressure, confirming the theoretical prediction. Numerical simulations verify that negative pressure in nanowires is the origin of the enhanced electromechanical properties. The results may be useful in the development of highly performing piezoelectrics, including lead-free ones. PMID:27396411

  8. Piezoelectric enhancement under negative pressure

    NASA Astrophysics Data System (ADS)

    Kvasov, Alexander; McGilly, Leo J.; Wang, Jin; Shi, Zhiyong; Sandu, Cosmin S.; Sluka, Tomas; Tagantsev, Alexander K.; Setter, Nava

    2016-07-01

    Enhancement of ferroelectric properties, both spontaneous polarization and Curie temperature under negative pressure had been predicted in the past from first principles and recently confirmed experimentally. In contrast, piezoelectric properties are expected to increase by positive pressure, through polarization rotation. Here we investigate the piezoelectric response of the classical PbTiO3, Pb(Zr,Ti)O3 and BaTiO3 perovskite ferroelectrics under negative pressure from first principles and find significant enhancement. Piezoelectric response is then tested experimentally on free-standing PbTiO3 and Pb(Zr,Ti)O3 nanowires under self-sustained negative pressure, confirming the theoretical prediction. Numerical simulations verify that negative pressure in nanowires is the origin of the enhanced electromechanical properties. The results may be useful in the development of highly performing piezoelectrics, including lead-free ones.

  9. 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.

  10. Characterization of the Global Hawk Low Pressure Turbine First Rotor

    DTIC Science & Technology

    2005-09-01

    Unmanned aerial vehicles USAF United States Air Force VBI Vane blade interaction VGD Vortex generator device VGJ Vortex generator jet xvii...top of the tunnel, and positions the downstream Kiel probe and hot-film, and the upstream pitot -static probe. This traverse is controlled through the...inlet total pressure from the upstream pitot -static probe. The Scanivalve determine whether the input to the other side of the Druck is inlet static

  11. Revised National Pressure Ulcer Advisory Panel Pressure Injury Staging System

    PubMed Central

    Black, Joyce M.; Goldberg, Margaret; McNichol, Laurie; Moore, Lynn; Sieggreen, Mary

    2016-01-01

    Our understanding of pressure injury etiology and development has grown in recent years through research, clinical expertise, and global interdisciplinary expert collaboration. Therefore, the National Pressure Ulcer Advisory Panel (NPUAP) has revised the definition and stages of pressure injury. The revision was undertaken to incorporate the current understanding of the etiology of pressure injuries, as well as to clarify the anatomical features present or absent in each stage of injury. An NPUAP-appointed Task Force reviewed the literature and created drafts of definitions, which were then reviewed by stakeholders and the public, including clinicians, educators, and researchers around the world. Using a consensus-building methodology, these revised definitions were the focus of a multidisciplinary consensus conference held in April 2016. As a result of stakeholder and public input, along with the consensus conference, important changes were made and incorporated into the new staging definitions. The revised staging system uses the term injury instead of ulcer and denotes stages using Arabic numerals rather than Roman numerals. The revised definition of a pressure injury now describes the injuries as usually occurring over a bony prominence or under a medical or other device. The revised definition of a Stage 2 pressure injury seeks to clarify the difference between moisture-associated skin damage and injury caused by pressure and/or shear. The term suspected has been removed from the Deep Tissue Pressure Injury diagnostic label. Each definition now describes the extent of tissue loss present and the anatomical features that may or may not be present in the stage of injury. These important revisions reflect the methodical and collaborative approach used to examine the available evidence and incorporate current interdisciplinary clinical expertise into better defining the important phenomenon of pressure injury etiology and development. PMID:27749790

  12. High-pressure optical studies

    SciTech Connect

    Drickamer, H.G.

    1981-01-01

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

  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

  14. Pressurized lunar rover

    NASA Astrophysics Data System (ADS)

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

    1992-05-01

    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.

  15. Dynamic-pressure measurements using an electronically scanned pressure module

    NASA Technical Reports Server (NTRS)

    Chapin, W. G.

    1983-01-01

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

  16. Parametric instability of pressurized propellant tanks

    NASA Astrophysics Data System (ADS)

    Albus, Jochen; Dieker, Stefan; Őry, Huba; Rittweger, Andreas

    2008-01-01

    Pressurized propellant tanks might become dynamically unstable with detrimental dynamic responses if a dynamic excitation leads to a coupling of pressure oscillations (especially due to the response of axisymmetric modes) with very low damped ovalizing modes. This phenomenon can be described and identified as the so-called parametric instability. During the dynamic qualification test campaign of the new Ariane 5 Cryogenic Upper Stage ESC-A, a parametric instability was observed for sinusoidal tests under certain test conditions with low static pressure in the propellant tank. The parametric instability was identified and an analytical simulation was performed that confirmed the instability. During flight, harmonic excitations might occur due to pressure oscillations within the solid rocket booster. However, the application of the analytical model on flight conditions indicates that the flight behaviour will be stable. This was confirmed by results from additional tests. This paper describes the phenomenon of the parametric instability of pressurized propellant tanks and presents an analytical methodology to assess the risk of the occurrence of a parametric instability.

  17. 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

  18. Test for pressure control capacity of the Eustachian tube.

    PubMed

    Kitahara, M; Kodama, A; Ozawa, H; Izukura, H; Inoue, S

    1994-01-01

    Because of Eustachian tube controls middle ear pressure to maintain the best hearing level, we tested the equilibration capacity of the Eustachian tube by measuring hearing levels in a soundproof pressure chamber. The number of swallows to recover normal hearing after the chamber pressure reached -200 mm H2O (an index of equilibration capacity for the static pressure differences across the eardrum) was less than 9 in normal subjects. The worst level of hearing and the time required to recover normal hearing from the beginning of alteration in the chamber pressure to -700 mm H2O (indexes of equilibration capacity for dynamic pressure differences across the eardrum) were 0-17 dB and within 120s in normal subjects. It was difficult to determine definitive normal ranges of the equilibrium capacity of the Eustachian tube when positive pressure was applied.

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

    PubMed

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

    2010-05-01

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

  20. 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

  1. High blood pressure in women.

    PubMed

    Calhoun, D A; Oparil, S

    1997-01-01

    There is a sexual dimorphism in blood pressure of humans and experimental animals: males tend to have higher blood pressure than females with functional ovaries, while ovariectomy or menopause tends to abolish the sexual dimorphism and cause females to develop a "male" pattern of blood pressure. Hypertensive male laboratory animals tend to have NaCl-sensitive blood pressure, while females are NaCl resistant unless their ovaries are removed, in which case NaCl sensitivity appears. The hormonal basis of NaCl sensitivity of blood pressure and of the sexual dimorphism of hypertension remains to be defined. Synthetic estrogens and progestins, as found in oral contraceptives, tend to elevate blood pressure, while naturally occurring estrogens lower it, or have no effect. Hypertension increases cardiovascular risk in women, as well as men, although the benefits of antihypertensive treatment have been more difficult to demonstrate in women. In the population of the United States, women are more aware of their hypertension, more likely to be treated medically, and more likely to have their blood pressure controlled.

  2. Chaos in blood pressure control.

    PubMed

    Wagner, C D; Nafz, B; Persson, P B

    1996-03-01

    A number of control mechanisms are comprised within blood pressure regulation, ranging from events on the cellular level up to circulating hormones. Despite their vast number, blood pressure fluctuations occur preferably within a certain range (under physiological conditions). A specific class of dynamic systems has been extensively studied over the past several years: nonlinear coupled systems, which often reveal a characteristic form of motion termed "chaos". The system is restricted to a certain range in phase space, but the motion is never periodic. The attractor the system moves on has a non-integer dimension. What all chaotic systems have in common is their sensitive dependence on initial conditions. The question arises as to whether blood pressure regulation can be explained by such models. Many efforts have been made to characterise heart rate variability and EEG dynamics by parameters of chaos theory (e.g., fractal dimensions and Lyapunov exponents). These method were successfully applied to dynamics observed in single organs, but very few studies have dealt with blood pressure dynamics. This mini-review first gives an overview on the history of blood pressure dynamics and the methods suitable to characterise the dynamics by means of tools derived from the field of nonlinear dynamics. Then applications to systemic blood pressure are discussed. After a short survey on heart rate variability, which is indirectly reflected in blood pressure variability, some dynamic aspects of resistance vessels are given. Intriguingly, systemic blood pressure reveals a change in fractal dimensions and Lyapunov exponents, when the major short-term control mechanism--the arterial baroreflex--is disrupted. Indeed it seems that cardiovascular time series can be described by tools from nonlinear dynamics [66]. These methods allow a novel description of some important aspects of biological systems. Both the linear and the nonlinear tools complement each other and can be useful in

  3. Blood Pressure and Physical Function

    PubMed Central

    Forbang, Nketi; Ix, Joachim; Criqui, Michael; Rifkin, Dena

    2014-01-01

    Background: Hypertension in older adults is a dynamic process, with significant diurnal fluctuation. Little research has been done on the associations between increased short-term blood pressure variability and blunted night-time dipping in respect to decreased physical function in the elderly. Our aim is to use a cross-sectional analysis to illuminate any associations. Methods: A cross-sectional sub-study (mean age: 72, 67.5% female) was performed on selected participants from the San Diego Population Study (Criqui, et al, 2003). Blood pressure was measured both in the office (3 independent blood pressure readings) and using a 24-hour ambulatory blood pressure monitoring cuff. Blood pressure variability was measured using average real variability (ARV). Physical function was measured using the Short Physical Performance Battery (SPPB) test. Statistical analysis was performed on IBM SPSS Statistics (1911) software. Results: An unadjusted univariate analysis adjusted for age and gender showed associations between 24-hr ARV of SBP (P = .001), 24-hr ARV pulse pressure (P < .001), and percent systolic dipping (P = .011) and SPPB score. After multivariate analysis adjusted for age and gender was performed, the results were substantially attenuated. However, the association of ARV of SBP was not significant with a P-value of .052 and the ARV of pulse pressure remained significant with a P-value of .022. Multivariate hierarchical linear regression models revealed insignificant trends. Conclusions: Increased short-term variability and blunted night-time dipping were associated physical function but were not independent of age and body mass index (BMI). Further research can be done as to the biology of how both age and BMI influence blood pressure patterns. The trends observed in this study may warrant the investigation of abnormal blood pressure patterns in those who are either elderly or have increased BMI.

  4. 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

  5. Steel pressure vessels for hydrostatic pressures to 50 kilobars.

    PubMed

    Lavergne, A; Whalley, E

    1978-07-01

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

  6. 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.

  7. Electrokinetic high pressure hydraulic system

    DOEpatents

    Paul, Phillip H.; Rakestraw, David J.

    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.

  8. Graphite filament wound pressure vessels

    NASA Technical Reports Server (NTRS)

    Feldman, A.; Damico, J. J.

    1972-01-01

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

  9. 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

  10. Self pressuring HTP feed systems

    SciTech Connect

    Whitehead, J.

    1999-10-14

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

  11. Pressure sensor for sealed containers

    DOEpatents

    Hodges, Franklin R.

    2001-01-01

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

  12. High pressure pulsed capillary viscometry

    NASA Technical Reports Server (NTRS)

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

    1972-01-01

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

  13. Precision ozone vapor pressure measurements

    NASA Technical Reports Server (NTRS)

    Hanson, D.; Mauersberger, K.

    1985-01-01

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

  14. 46 CFR 54.10-5 - Maximum allowable working pressure (reproduces UG-98).

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... adjusted for any difference in static head that may exist between the part considered and the top of the... internal or external pressure, including the static head hereon, as determined by the rules and formulas...

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

    DOEpatents

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

    2008-09-23

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

  16. Measurement of pulse pressure in plasma by crusher gauge

    SciTech Connect

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

    1988-06-01

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

  17. Hydrogen at extreme pressures (Review Article)

    NASA Astrophysics Data System (ADS)

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

    2013-05-01

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

  18. Pressure induced polymerization of Formates

    NASA Astrophysics Data System (ADS)

    Tschauner, Oliver

    2004-03-01

    The discovery of pressure induced polymerization of CO2 inspired us to search for C-O based chain structures forming at high pressure. We used salts of carboxylic acids as starting materials and exposed them to pressures between 10 and 30 GPa. Upon heating to temperatures above 1800 K we observed deprotonation and significant changes in the Raman shifts of C-O streching modes. Structure analysis based on powder diffraction patterns collected at sector 16 of the APS showed formation of extended C-O chain structures with the cations of the salts residing in the interchain spaces. These new high pressure polymers are interesting by their mechanical strength and provide basic molecular patterns of organic metallic conductors.

  19. Negative-Pressure Pulmonary Edema.

    PubMed

    Bhattacharya, Mallar; Kallet, Richard H; Ware, Lorraine B; Matthay, Michael A

    2016-10-01

    Negative-pressure pulmonary edema (NPPE) or postobstructive pulmonary edema is a well-described cause of acute respiratory failure that occurs after intense inspiratory effort against an obstructed airway, usually from upper airway infection, tumor, or laryngospasm. Patients with NPPE generate very negative airway pressures, which augment transvascular fluid filtration and precipitate interstitial and alveolar edema. Pulmonary edema fluid collected from most patients with NPPE has a low protein concentration, suggesting hydrostatic forces as the primary mechanism for the pathogenesis of NPPE. Supportive care should be directed at relieving the upper airway obstruction by endotracheal intubation or cricothyroidotomy, institution of lung-protective positive-pressure ventilation, and diuresis unless the patient is in shock. Resolution of the pulmonary edema is usually rapid, in part because alveolar fluid clearance mechanisms are intact. In this review, we discuss the clinical presentation, pathophysiology, and management of negative-pressure or postobstructive pulmonary edema.

  20. 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.