WorldWideScience

Sample records for bottom-hole pressure

  1. Better well control through safe drilling margin identification, influx analysis and direct bottom hole pressure control method for deep water

    Energy Technology Data Exchange (ETDEWEB)

    Veeningen, Daan [National Oilwell Varco IntelliServ (NOV), Houston, TX (United States)

    2012-07-01

    Currently, well control events are almost exclusively detected by using surface measurements. Measuring a volume increase in the 'closed loop' mud circulation system; a standpipe pressure decrease; or changes in a variety of drilling parameters provide indicators of a kick. Especially in deep water, where the riser comprises a substantial section of the well bore, early kick detection is paramount for limiting the severity of a well bore influx and improve the ability to regain well control. While downhole data is presently available from downhole tools nearby the bit, available data rates are sparse as mud pulse telemetry bandwidth is limited and well bore measurements compete with transmission of other subsurface data. Further, data transfer is one-directional, latency is significant and conditions along the string are unknown. High-bandwidth downhole data transmission system, via a wired or networked drill string system, has the unique capability to acquire real-time pressure and temperature measurement at a number of locations along the drill string. This system provides high-resolution downhole data available at very high speed, eliminating latency and restrictions that typically limit the availability of downhole data. The paper describes well control opportunities for deep water operations through the use of downhole data independent from surface measurements. First, the networked drill string provides efficient ways to identify pore pressure, fracture gradient, and true mud weight that comprise the safe drilling margin. Second, the independent measurement capability provides early kick detection and improved ability to analyze an influx even with a heterogeneous mud column through distributed along-string annular pressure measurements. Third, a methodology is proposed for a direct measurement method using downhole real-time pressure for maintaining constant bottom hole pressure during well kills in deep water. (author)

  2. Experimental and numerical simulations of bottom hole temperature and pre-ssure distributions of supercritical CO2 jet for well-drilling

    Institute of Scientific and Technical Information of China (English)

    王瑞和; 霍洪俊; 黄志远; 宋慧芳; 倪红坚

    2014-01-01

    The supercritical carbon dioxide (SC-CO2) drilling is a novel drilling technique developed in recent years. A detailed study of temperature and pressure distributions of the SC-CO2 jet on the bottom of a well is essensial to the SC-CO2 drilling. In this paper, the distributions of pressure and temperature on the bottom of the hole during the SC-CO2 jet drilling are simulated experimentally and numerically, and the impacts of the nozzle diameter, the jet length, and the inlet pressure of the SC-CO2 jet are analyzed. It is shown that, the bottom hole temperature and pressure increase with the increase of the nozzle diameter, and the bottom hole temperature reduces and the pressure increases first and then decreases with the increase of the jet length, indicating that the jet length has an optimum value. The increase of the inlet pressure can increase the temperature and pressure on the bottom, which has a positive effect on the drilling rate.

  3. 煤层气井底流压生产动态研究%Production dynamics of CBM bottom hole pressure

    Institute of Scientific and Technical Information of China (English)

    赵金; 张遂安

    2013-01-01

      井底流压对煤层气的开采至关重要.在考虑煤层产水量与井底流压的耦合作用下,基质量和能量守恒定律建立了计算井底流压的数学模型.采用压力增量迭代法,利用 matlab7.11编写了求解程序,分析了排采参数相互间的关系.研究结果表明:产水量与井底流压两者的关系呈非线性关系;储层渗透率越好、煤层厚度越厚,产水量与井底流压的耦合关系会更显著些;气液两相流阶段中,高产气量不仅能降低环空中气体流动的压降损失,还利煤层气在地面管汇的运输.%Bottom hole pressure (BHP) has a great effect on CBM production, so it’s necessary for us to calculate BHP accurately during CBM production. The mathematical models of BHP calculation were developed based on mass conservation law and energy conservation law, considering the influence between water production and BHP during the flow process. Matlab7.11 was used to write solving program. And the relationship among operational parameters and their effects on deliverability were analyzed. The results show that the coupling effect between water production in coal seam and BHP make them not follow a linear relationship, especially when reservoir per-meability is good and coal seam is thick. High gas production rate can not only reduce pressure drop losses in the ring, but is convenient for CBM transportation on the ground.

  4. Development of Radar Navigation and Radio Data Transmission for Microhole Coiled Tubing Bottom Hole Assemblies

    Energy Technology Data Exchange (ETDEWEB)

    Larry G. Stolarczyk; Gerald L. Stolarczyk; Larry Icerman; John Howard; Hooman Tehrani

    2007-03-25

    This Final Technical Report summarizes the research and development (R&D) work performed by Stolar Research Corporation (Stolar) under U.S. Department of Energy (DOE) Contract Number DE-FC26-04NT15477. This work involved the development of radar navigation and radio data transmission systems for integration with microhole coiled tubing bottom hole assemblies. Under this contract, Stolar designed, fabricated, and laboratory and field tested two advanced technologies of importance to the future growth of the U.S. oil and gas industry: (1) real-time measurement-while-drilling (MWD) for guidance and navigation of coiled tubing drilling in hydrocarbon reservoirs and (2) two-way inductive radio data transmission on coiled tubing for real-time, subsurface-to-surface data transmission. The operating specifications for these technologies are compatible with 3.5-inch boreholes drilled to a true vertical depth (TVD) of 5,000 feet, which is typical of coiled tubing drilling applications. These two technologies (i.e., the Stolar Data Transmission System and Drill String Radar) were developed into pre-commercial prototypes and tested successfully in simulated coiled tubing drilling conditions. Integration of these two technologies provides a real-time geosteering capability with extremely quick response times. Stolar is conducting additional work required to transition the Drill String Radar into a true commercial product. The results of this advanced development work should be an important step in the expanded commercialization of advanced coiled tubing microhole drilling equipment for use in U.S. hydrocarbon reservoirs.

  5. Gas Well Bottom Hole Locations, LP and LNG, Utah Oil and Gas Well Bottom Hole Points for horizontallly drilled wells only. From the Utah Department of Natural Resources, Oil Gas and Mining Division., Published in 2000, 1:100000 (1in=8333ft) scale, State of Utah Automated Geographic Reference Center.

    Data.gov (United States)

    NSGIC GIS Inventory (aka Ramona) — This Gas Well Bottom Hole Locations, LP and LNG dataset, published at 1:100000 (1in=8333ft) scale, was produced all or in part from Other information as of 2000. It...

  6. Dynamical analysis of high-pressure supercritical carbon dioxide jet in well drilling

    Institute of Scientific and Technical Information of China (English)

    DU Yu-kun; WANG Rui-he; NI Hong-jian; HUANG Zhi-yuan; LI Mu-kun

    2013-01-01

    This paper presents the design of an experimental setup and mathematical and physical models to determine the dynamical characteristics of the high-pressure supercritical carbon dioxide (SC-CO2) jet with a highly potential applications in the well drilling.The effects of three major factors on the wellbore dynamical characteristics of the high-pressure SC-CO2 jet,i.e.,the nozzle diameter,the standoff distance and the jet pressure are determined.It is indicated that the pressure of CO2 reduces severely in the SC-CO2 jet impact process.It is also found that the bottom-hole pressure and the temperature increase as the nozzle diameter increases but decrease with the increase of the standoff distance.The higher the jet pressure at the wellbore inlet is,the higher the pressure and the lower the temperature at the bottom-hole will be.

  7. 水平井井底钻压的研究%A RESEARCH ON BOTTOM HOLE BIT WEIGHT IN A HORIZONTAL WELL

    Institute of Scientific and Technical Information of China (English)

    肖建波; 雷宗明

    2001-01-01

    apparent pressure during drilling are proposed in the paper also.

  8. Simulation and modeling of pressure pulse propagation in fluids inside drill strings

    OpenAIRE

    Namuq, Mohammed Ali

    2013-01-01

    Modern bottom-hole assemblies are equipped with various sensors which measure the geological and directional information of the borehole while drilling. It is very crucial to get the measured downhole information to the surface in real time in order to be able to monitor, steer and optimize the drilling process while drilling. The transmission of the information to the surface is most commonly carried out by coded pressure pulses (the technology called mud pulse telemetry) which propagate thr...

  9. DRILLING CHARACTERISTICS OF COMBINATIONS OF DIFFERENT HIGH PRESSURE JET NOZZLES

    Institute of Scientific and Technical Information of China (English)

    ZHANG Yu-ying; LIU Yong-wang; XU Yi-ji; REN Jian-hua

    2011-01-01

    The high speed fluid jet for directly or indirectly breaking rock is one of the most effective ways to improve the deep penetration rate. In order to maximize the efficiency of energy use, the flow characteristics of different combinations of high pressure jet nozzles are analyzed through numerical simulations. According to the velocity vectors at the bottom and the bottom hole pressure diagram, the effects of the high pressure nozzle combinations on the flow structure and the penetration rate are analyzed. It is shown that the combination of three vertical edge nozzles is very efficient, but inefficient in cleaning the bottom hole and eroding the wall.The jet velocity is 400 m/s and the radius is 5 mm, with a center nozzle added, the problem can be solved, but the high-pressure fluid displacement would increase. The center nozzle's jet velocity is 200 m/s and the radius is 8 mm, the combination of two vertical edge nozzles and a center tilt nozzle or that of a vertical edge nozzle and a center tilt nozzle would provide a flow structure favorable for drilling. The angle of inclination is 10°. To take advantage of high pressure jet energy to improve the efficiency of drilling, it is important to select a suitable nozzle combination according real conditions.

  10. Analytical modeling of pressure transient behavior for coalbed methane transport in anisotropic media

    Science.gov (United States)

    Wang, Lei; Wang, Xiaodong

    2014-06-01

    Resulting from the nature of anisotropy of coal media, it is a meaningful work to evaluate pressure transient behavior and flow characteristics within coals. In this article, a complete analytical model called the elliptical flow model is established by combining the theory of elliptical flow in anisotropic media and Fick's laws about the diffusion of coalbed methane. To investigate pressure transient behavior, analytical solutions were first obtained through introducing a series of special functions (Mathieu functions), which are extremely complex and are hard to calculate. Thus, a computer program was developed to establish type curves, on which the effects of the parameters, including anisotropy coefficient, storage coefficient, transfer coefficient and rate constant, were analyzed in detail. Calculative results show that the existence of anisotropy would cause great pressure depletion. To validate new analytical solutions, previous results were used to compare with the new results. It is found that a better agreement between the solutions obtained in this work and the literature was achieved. Finally, a case study is used to explain the effects of the parameters, including rock total compressibility coefficient, coal medium porosity and anisotropic permeability, sorption time constant, Langmuir volume and fluid viscosity, on bottom-hole pressure behavior. It is necessary to coordinate these parameters so as to reduce the pressure depletion.

  11. Transient flow model and pressure dynamic features of tree-shaped fractal re- servoirs

    Institute of Scientific and Technical Information of China (English)

    TAN Xiao-hua; LI Xiao-ping

    2014-01-01

    A transient flow model of tree-shaped fractal reservoirs is built by embedding a fracture network simulated by a tree-shaped fractal network into a matrix system. The model can be solved using the Laplace conversion method. The dimensionless bottom hole pressure can be obtained using the Stehfest numerical inversion method. The bi-logarithmic type curves for the tree-shaped fractal reservoirs are thus obtained. The pressure transient responses under different fractal factors are discussed. The factors with a primary effect on the inter-porosity flow regime include the initial branch numberN, the length ratioα, and the branch angleθ. The diameter ratioβ has a significant effect on the fracture radial flow, the inter-porosity and the total system radial flow regimes. The total branch levelM of the network mainly influences the total system radial flow regime. The model presented in this paper provides a new methodology for analyzing and predicting the pressure dynamic characteristics of naturally fractured reservoirs.

  12. Blood pressure

    Science.gov (United States)

    ... the walls of the arteries is called blood pressure. Blood pressure is measured both as the heart contracts, which ... as it relaxes, which is called diastole. Normal blood pressure is considered to be a systolic blood pressure ...

  13. Peer Pressure

    Science.gov (United States)

    ... How Can I Help a Friend Who Cuts? Peer Pressure KidsHealth > For Teens > Peer Pressure Print A A A Text Size What's in ... She'd just had a big dose of peer pressure. Who Are Your Peers? When you were a ...

  14. 智能电控存储式油井分层测压仪研制%Stratified Pressure Instrument Development for Intelligent Electronic-controlled Oilwell

    Institute of Scientific and Technical Information of China (English)

    刘伟; 徐德奎; 姜春雷

    2011-01-01

    Basing on developing Annular technology, a smart and stratified pressure instrument for electroniccontrolled oilwell was developed. Of the instrument consisting of control modules for automatic setting, release and drive, and that for pressure measurement and host ground controller, the ground-controlled releasing motor can set the supporting arm of pressure instrument at detent mechanism of the bottom-hole regulator, and the control module for automatic setting and release can drive the underground motor to implement the setting and releasing operation of pressure instruments, and its testing module can record both single-layer static pressure and flowing pressure in the oilwell.%在研制过环空的基础上,开发智能电控存储油井分层测压仪.该测压仪主要由井下自动坐封、解封控制及驱动模块、测压仪丢手控制及驱动模块、压力测试模块、地面控制主机等部分构成.地面控制丢手电机使仪器定位支臂支承在配产器定位机构上;自动坐封、解封控制及驱动模块控制留在井下的坐封电机,实现测压仪坐封、解封,压力计测试模块记录油井单层静压和流压.

  15. Analytical solution of geological carbon sequestration under constant pressure injection into a horizontal radial reservoir

    Science.gov (United States)

    Jhang, R.; Liou, T.

    2013-12-01

    Carbon capture and sequestration (CCS) is believed to be an economically feasible technology to mitigate global warming by capturing carbon dioxide (CO2), the major component of greenhouse gases, from the atmosphere and injecting it into deep geological formations.Several mechanisms can help trap CO2 in the pore space of a geological reservoir, stratigraphic and structural trapping, hydrodynamic trapping, and geochemical trapping.Besides these trapping mechanisms, another important issue that deserves careful attention is the risk of CO2 leakage. The common ';constant injection rate' scenario may induce high pressure buildup that will endanger the mechanical integrity as well as the sealing capability of the cap rock. Instead of injecting CO2 at a constant mass rate, CO2 can be injected into the reservoir by fixing the pressure (usually the bottom-hole pressure) in the injection borehole. By doing so, the inevitable pressure buildup associated with the constant injection scheme can be completely eliminated in the constant pressure injection scheme. In this paper, a semi-analytical solution for CO2 injection with constant pressure was developed. For simplicity, structural and geochemical trapping mechanisms were not considered. Therefore, a horizontal reservoir with infinite radial extent was considered. Prior to injection, the reservoir is fully saturated with the formation brine. It is assumed that CO2 does not mix with brine such that a sharp interface is formed once CO2 invades the brine-saturated pores. Because of the density difference between CO2 and brine, CO2 resides above the interface. Additional assumptions were also made when building up the brine and CO2 mass balance equations: (1) both of the fluids and the geological formations are incompressible, (2) capillary pressure is neglected, (3)there is no fluid flow in the vertical direction, and the horizontal flow satisfies the Darcy's law.In order to solve for the height of brine-CO2 interface, the two

  16. Case studies of the application of enhanced steel alloys for bottom hole assembly components for sour service conditions

    Energy Technology Data Exchange (ETDEWEB)

    Chan, Alvaro [Nov Grant Prideco, Navasota (United States); Moura, Carlos [ASPEN Assesoria Tecnica e Comercial, Cascavel, PR (Brazil); Johnson, Charles; Landriault, Alain [Weatherford Canda Partnership, Calgary, AB (Canada)

    2008-07-01

    The new more modern drilling programs require the drill string to travel across sour formations in order to reach the hydrocarbon reservoirs. Traditional materials have been employed in the manufacture of HWDP components along with basic heat treatment processes. Standard HWDP tools have started to show their operational as well as environmental limitations when subjected to sour service applications. The advanced, more complex drilling programs require for the HWDP tools to be put in service under different configurations. Either at the bottom of the drill string near the drill bit for vertical well configurations or on top of the drill string for weight application on horizontal or extended reach applications. An operator in northwestern Canada has replaced standard HWDP with enhanced sour service HWDP in order to complete the programmed wells. These enhanced tools offer higher tensile and torque capabilities and improved toughness than standard HWDP tools and in addition, provide protection against sour service conditions. The use of second-generation double shoulder connections (2nd-Gen. DSC) has also provided added torque and tensile capacities to these versatile HWDP tools. For over a year more than a dozen wells have been drilled employing these enhanced BHA tools and have helped the operator reach its targets through sour service formations and produce wells in a safe and cost effective manner. (author)

  17. Pressure sensor

    Energy Technology Data Exchange (ETDEWEB)

    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. Chemical pressure

    OpenAIRE

    Hauser, Andreas; Amstutz, Nahid; Delahaye, Sandra; Sadki, Asmaâ; Schenker, Sabine; Sieber, Regula; Zerara, Mohamed

    2002-01-01

    The physical and photophysical properties of three classic transition metal complexes, namely [Fe(bpy)3]2+, [Ru(bpy)3]2+, and [Co(bpy)3]2+, can be tuned by doping them into a variety of inert crystalline host lattices. The underlying guest-host interactions are discussed in terms of a chemical pressure.

  19. Pressurized hopper

    International Nuclear Information System (INIS)

    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

  20. Blood pressure measurement

    Science.gov (United States)

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

  1. Blood Pressure Quiz

    Science.gov (United States)

    ... page please turn Javascript on. Feature: High Blood Pressure Blood Pressure Quiz Past Issues / Fall 2011 Table of Contents ... About High Blood Pressure / Treatment: Types of Blood Pressure Medications / Blood Pressure Quiz Fall 2011 Issue: Volume 6 Number ...

  2. Hypertension (High Blood Pressure)

    Science.gov (United States)

    ... right away. continue How Do Doctors Measure Blood Pressure? Blood pressure readings are fast and painless. Blood pressure ... same age, height, and gender have lower blood pressure. Blood pressure between 90% and 95% of the normal ...

  3. High Blood Pressure (Hypertension)

    Science.gov (United States)

    ... your doctor prescribes it, medicine. What Is Blood Pressure? Blood pressure is the force of blood flow inside ... Will I Know if I Have High Blood Pressure? High blood pressure is a silent problem — you won't ...

  4. Understanding Blood Pressure Readings

    Science.gov (United States)

    ... What is the AHA recommendation for healthy blood pressure? This blood pressure chart reflects categories defined by the American ... unusually low blood pressure readings. How is high blood pressure diagnosed? Your healthcare providers will want to get ...

  5. High Blood Pressure

    Science.gov (United States)

    ... pressure and should be taken seriously. Over time, consistently high blood pressure weakens and damages ... of landmark NIH blood pressure study confirm that lower blood pressure target can reduce ...

  6. 双区复合煤层气压力动态特征分析%ANALYSES ON THE PRESSURE DYNAMIC CHARACTERISTICS OF COMPOSITE COAL-BED GAS WITH DOUBLE POROSITIES

    Institute of Scientific and Technical Information of China (English)

    李涛; 董平川; 曹丽丽

    2012-01-01

    Aiming at the heterogeneity of formation itself and the polluted belts around the wells in the processes of drilling, well completion and production for coal-bed gas, the well-testing interpretation model for the composite coal-bed gas with double porosities is established. The model considers not only the effects of borehole storage effect and skin effect, but also the non-equilibrium adsorption and quasi-steady seepage conditions. It gives the pressure solution under the condition of infinite outer boundary, and furthermore the typical curves of bottom hole pressure drop are drawn, the influences of each parameter on the curves are analyzed. The study achievements have provided a theoretical basis for coal-bed gas reservoir development.%针对煤层气在钻井、完井、开采过程中井周围产生污染带以及地层本身的非均质情况,建立了既考虑井筒储存效应及表皮污染的影响,又考虑非平衡态吸附及拟稳态渗流条件的分区复合煤层气试井解释模型,求出了无限大外边界条件下的煤层气藏压力解,并绘制了井底压降典型曲线,就各参数对典型曲线的影响进行了分析.研究成果为煤层气藏开发提供了理论依据.

  7. Medications and Blood Pressure

    Science.gov (United States)

    ... Blood Pressure Tools & Resources Stroke More Medications and Blood Pressure Updated:Jul 6,2016 When your blood pressure ... was last reviewed on 08/04/2014. High Blood Pressure • Home • About High Blood Pressure (HBP) • Why HBP ...

  8. High Blood Pressure

    Science.gov (United States)

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

  9. High blood pressure - infants

    Science.gov (United States)

    National High Blood Pressure Education Program Working Group on High Blood Pressure in Children and Adolescents. The fourth report on the diagnosis, evaluation, and treatment of high blood pressure in children and adolescents. Pediatrics . ...

  10. High Blood Pressure Facts

    Science.gov (United States)

    ... Heart Disease Cholesterol Salt Million Hearts® WISEWOMAN High Blood Pressure Facts Recommend on Facebook Tweet Share Compartir ... facts about high blood pressure [PDF-255K] . High Blood Pressure in the United States About 70 million ...

  11. Preventing Pressure Sores

    Medline Plus

    Full Text Available ... Preventing Pressure Sores Preventing Pressure Sores Transition from Hospital to Home Transition from Hospital to Home Spasticity, Physical Therapy-Lokomat Spasticity, Physical ...

  12. Preventing Pressure Sores

    Medline Plus

    Full Text Available ... Injury 101 The Basics of Spinal Cord Injury Rehabilitation The Basics of Spinal Cord Injury Rehabilitation Preventing Pressure Sores Preventing Pressure Sores Transition from ...

  13. An investigation of constant pressure gas well testing influenced by high velocity flow

    Energy Technology Data Exchange (ETDEWEB)

    Berumen, S. [PEMEX Exploracion-Produccion, Mexico City (Mexico); Samaniego, F. [Universidad de Mexico, Mexico City (Mexico). Facultad de Ingeniera; Cinco-Ley, H. [Universidad de Mexico, Mexico City (Mexico). Facultad de Ingeniera; Bouhroum, A.

    1997-03-01

    This paper presents the results of a study of transient pressure analysis of gas flow under either constant bottom-hole conditions or the constant wellhead pressure conditions. The effect of formation damage, wellbore storage and high velocity flow are included in the model. The analysis of simulated well tests showed that the interpretation methods used for liquid flow are generally accurate when the p{sub p}(p) is used. For these conditions, a graph of 1/q{sub D} vs log t{sub D} presents gradually lower values of 1.1513 as the value of p{sub wf} decreases: For pressure buildup conditions a graph of p{sub pD}(1, {Delta}t{sub aD})/q{sub D}({Delta}t{sub aD}=0) vs (t{sub aD}+{Delta}t{sub aD})/{Delta}t{sub aD} shows values of this slope within 1% of the 1.1513 value. The maximum error was in the rate performance simulated cases that included high-velocity flows; being less than 13%. This upper limit occurs when the formation has a relatively `high` permeability (around 1 mD) and the rate performance test is affected by high-velocity flow. It was found that pressure buildup tests are superior to rate performance tests because high-velocity flow does not affect the slope of the straight line portion of the buildup curve. However, it was also found, through derivative analysis of simulated buildup tests, that the skin factor is sensibly miscalculated when the high-velocity flow effect is singificant. This problem could lead to errors in the calculation of the skin factor, s, up to 300%. (orig.) [Deutsch] Vorgestellt werden instationaere Testergebnisse an Gas-Sonden unter konstanten Bohrlochsohlenbedingungen bzw. konstantem Bohrlochkopfdruck. Folgende Stoereffekte: Sondennahe Tragerschaedigung, Speicherkapazitaet des Bohrloches und die bei der Gasstroemung eintretende hohe Fliessgeschwindigkeit werden beruecksichtigt. Die Auswertung von simulierten Testergebnissen zeigt, dass die zur Interpretation von Erdoelsonden bewaehrten Verfahren in der Darstellung p{sub p}(p) gute

  14. High blood pressure medications

    Science.gov (United States)

    ... this page: //medlineplus.gov/ency/article/007484.htm High blood pressure medicines To use the sharing features on this page, please enable JavaScript. Treating high blood pressure will help prevent problems such as heart disease, ...

  15. Hypertension (High Blood Pressure)

    Science.gov (United States)

    ... blood pressure with the development of a practical method to measure it. Physicians began to note associations between hypertension and risk of heart failure, stroke, and kidney failure. Although scientists had yet to prove that lowering blood pressure ...

  16. High blood pressure

    Science.gov (United States)

    ... you are at risk for: Bleeding from the aorta, the large blood vessel that supplies blood to ... tests Blood pressure check Blood pressure References American Diabetes Association. Standards of medical care in diabetes-2015 ...

  17. Blood Pressure Medicines

    Science.gov (United States)

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

  18. Pressure vessel design manual

    CERN Document Server

    Moss, Dennis R

    2013-01-01

    Pressure vessels are closed containers designed to hold gases or liquids at a pressure substantially different from the ambient pressure. They have a variety of applications in industry, including in oil refineries, nuclear reactors, vehicle airbrake reservoirs, and more. The pressure differential with such vessels is dangerous, and due to the risk of accident and fatality around their use, the design, manufacture, operation and inspection of pressure vessels is regulated by engineering authorities and guided by legal codes and standards. Pressure Vessel Design Manual is a solutions-focused guide to the many problems and technical challenges involved in the design of pressure vessels to match stringent standards and codes. It brings together otherwise scattered information and explanations into one easy-to-use resource to minimize research and take readers from problem to solution in the most direct manner possible. * Covers almost all problems that a working pressure vessel designer can expect to face, with ...

  19. Atmospheric Pressure Indicator.

    Science.gov (United States)

    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)

  20. Relative microvascular pressure sensing

    Science.gov (United States)

    Choi, Min; Zemp, Roger

    2016-03-01

    Microcirculation may be characterized by the vascular pressure as it is influenced by pressure-driven perfusion. Crosssections of blood vessels can be visualized by photoacoustic imaging and compressing on vessels causes deformation. The photoacoustic signals of blood, when compressed to the point of vessel collapse, may or may not vanish depending on the buckling process it undergoes. We form relative pressure images of microvessels by tracking vessel collapse as a function of externally applied pressure using photoacoustic imaging.

  1. High-pressure apparatus

    NARCIS (Netherlands)

    Schepdael, van L.J.M.; Bartels, P.V.; Berg, van den R.W.

    1999-01-01

    The invention relates to a high-pressure device (1) having a cylindrical high-pressure vessel (3) and prestressing means in order to exert an axial pressure on the vessel. The vessel (3) can have been formed from a number of layers of composite material, such as glass, carbon or aramide fibers which

  2. Pressure locking test results

    Energy Technology Data Exchange (ETDEWEB)

    DeWall, K.G.; Watkins, J.C.; McKellar, M.G.; Bramwell, D. [Idaho National Engineering Lab., Idaho Falls, ID (United States)] [and others

    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.

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

    Science.gov (United States)

    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...

  4. Pressure cryocooling protein crystals

    Science.gov (United States)

    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.

  5. Internationalization and migration pressure.

    Science.gov (United States)

    Kultalahti, O

    1994-01-01

    The author first develops the concept of migration pressure, which is defined as the growth in the number of people wishing to migrate and the barriers preventing them from so doing. Both macro- and micro-level factors affecting migration pressure are identified. Historical trends in migration pressure in Finland are then discussed. The author then applies this concept to the analysis of current Finnish migration trends. The primary focus is on international migration.

  6. Controlling your high blood pressure

    Science.gov (United States)

    ... that is healthy for you. Checking Your Blood Pressure Your blood pressure can be measured at many places, including: ... Alternative Names Controlling hypertension Images Taking your blood pressure at home Blood pressure check Low sodium diet References American Diabetes ...

  7. What Is High Blood Pressure?

    Science.gov (United States)

    ... also known as blood vessels and capillaries. The pressure --- blood pressure --- is the result of two forces. The ... was last reviewed on 08/04/2014. High Blood Pressure • Home • About High Blood Pressure (HBP) Introduction What ...

  8. High Blood Pressure Fact Sheet

    Science.gov (United States)

    ... much alcohol. Signs and Symptoms of High Blood Pressure High blood pressure usually has no warning signs or symptoms , ... they are at high risk for high blood pressure . Blood Pressure Levels Normal systolic: less than 120 mmHg ...

  9. ORANGE JUICE AND BLOOD PRESSURE

    OpenAIRE

    M. F. VALIM; Barros, S.

    2009-01-01

    Blood pressure is the force of blood against artery walls. It is measured in millimeters of mercury (mm Hg) and recorded as two numbers: systolic pressure (as the heart contracts) over diastolic pressure (as the heart relaxes between beats). High blood pressure (hypertension) is defined as chronically elevated high blood pressure, with systolic blood pressure (SBP) of 140 mm Hg or greater, and diastolic blood pressure (DBP) of 90 mm Hg or greater. High blood pressure ...

  10. Preventing High Blood Pressure

    Science.gov (United States)

    ... Heart Disease Cholesterol Salt Million Hearts® WISEWOMAN Preventing High Blood Pressure: Healthy Living Habits Recommend on Facebook Tweet Share ... meal and snack options can help you avoid high blood pressure and its complications. Be sure to eat plenty ...

  11. DIGITAL BLOOD PRESSURE MONITOR

    Directory of Open Access Journals (Sweden)

    R. Fuentes

    2004-12-01

    Full Text Available In this work we present a blood pressure monitor which measures both the high blood pressure (systolic pressure,and the low blood pressure (diastolic pressure. It is a semiautomatic meter because the inflation of the occlusivecuff is carried out in a manual way. The transducer used is a piezoresistive silicon pressure sensor integrated onchip which provides a proportional voltage to the input pressure, with a measurement range from 0 to 50 kPa (0–7.3 PSI. The oscillometric method is employed, which consists on detecting the oscillometric signal on brachialartery, being processed at each pressure step, when the cuff is gradually deflated. Signal sampling is carried out ata rate determined by the heart rate.In order to program the digital electronics of the circuit we used Altera tools, with the compiler MAX-PLUS II, andthe device selected to implement the design was an EPM7128SLC84-15 CPLD (Complex Programmable LogicDevice

  12. Neonatal Pressure Ulcer Prevention.

    Science.gov (United States)

    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. PMID:26803094

  13. Coping With Inflation Pressures

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    The pressure of higher prices is a major problem confronting the Chinese economy"We will be facing fairly great price pressures in 2008,"said Xie Fuzhan,Director of the National Bureau of Statistics(NBS),on January 24."Even if there are no new fac- tors causing price hikes,the inertia from the rises in 2007 is still devastating."

  14. Telemetry of intracranial pressure

    Science.gov (United States)

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

    1978-01-01

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

  15. Pressure Ulcers Surveillance Report

    Directory of Open Access Journals (Sweden)

    Zehra Esin Gencer

    2015-04-01

    Full Text Available Objective: Pressure ulcer is a chronic wound. It reduces the quality of life of the elderly and individuals with restricted range of motion. It prolongs hospital stay and increases the risk of complications. The cost is quite high. Preventive actions for the prevention of pressure ulcers should be developed. Planning protocols and standards of care are among the main targets. Material and Method: Research was conducted in one-year period between 2012 May and 2013 May on patients who were followed up in Akdeniz University Hospital clinics and intensive care unit with pressure ulcers. The research population consisted of 569 patients. Patient data were recorded in SPSS 16 for Windows program. Statistical analyzes were performed with retrospective methods. The demographic characteristics of patients with pressure ulcers were analyzed as frequency and descriptive statistics. Prevalence and incidence of one year were calculated. Results: Of the patients, 58% were males, 42% were females. Of the patients, 36% were in the age range of 61-80 years, and their average length of stay was 42,9 days. Of the patients, 70% were at stage 2 and 3. In 15% of patients pressure ulcers occurred on the first day of hospitalization. Pressure ulcers were developed between days 2 and 10 in 59% of the patients. Prevalence rate was 2.5%, the incidence was 1.9%, the prevalence rate was 5.9% in the intensive care unit. Conclusion: It is easier to prevent pressure ulcers than treating.

  16. Atmospheric Pressure During Landing

    Science.gov (United States)

    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.

  17. Preventing Pressure Sores

    Medline Plus

    Full Text Available ... wheelchair seat cushion? What’s important to know about positioning in bed to prevent pressure sores? What is “ ... provide medical advice, recommend or endorse health care products or services, or control the information found on ...

  18. Preventing Pressure Sores

    Science.gov (United States)

    ... wheelchair seat cushion? What’s important to know about positioning in bed to prevent pressure sores? What is “ ... provide medical advice, recommend or endorse health care products or services, or control the information found on ...

  19. A pressure regulator

    International Nuclear Information System (INIS)

    A device for regulating the pressure of a gas in a glove box comprises a resiliently biassed pressure sensitive diaphragm and a spool valve operable by deflection of the diaphragm. The diaphragm is arranged to be exposed on one side to atmospheric pressure and on the other side to the pressure of the gas in the glove box, and the spool valve is used to control simultaneously the rates at which gas is pumped in and out of the glove box. The valve spool has two axially spaced circumferential grooves A, B which provide communication between conduits C, D and E, F respectively, the flow control along each path being effected by means of apertures in a sleeve within which the spool slides. (author)

  20. Pressure Transducer Locations

    Data.gov (United States)

    National Aeronautics and Space Administration — Files are located here, defining the locations of the pressure transducers on the HIRENASD model. These locations also correspond to the locations that analysts...

  1. Preventing Pressure Sores

    Medline Plus

    Full Text Available ... with spinal cord injuries? What are the six stages of a pressure sore and how are they ... entire family FacingDisability is designed to provide Internet-based information and support for people with spinal cord ...

  2. More Pressure on Iran

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    As the UN Security Council adopts a new resolution to pressure Iran over its nuclear activities, the country maintains a tough stance On March 24, the UN Security Council unanimously adopted a new resolution imposing tougher sanctions against Iran to

  3. Capacitance pressure sensor

    Science.gov (United States)

    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).

  4. Critical CRBR core pressure

    International Nuclear Information System (INIS)

    The conditions are detailed under which gas pressure will cause or initiate failure in the structural containment of the fuel core. The Clinch River Breeder Reactor Plant is the prototype structure. Two general classes of problems have been studied, representing two entirely distinct configurations of containment failure. The first model determines the minimum pressure to lift a portion or the entire core from its containment. The second model estimates the critical pressure above which the fuel rods interior to the hexagonal fuel can warp, leading to blockage of the gas passages. Such blockage might cause further buildup of the gas pressure to a level causing the failure of the fuel rod containment in the hexagonal fuel container

  5. Metastable Systems under Pressure

    CERN Document Server

    Rzoska, Sylwester; Mazur, Victor

    2010-01-01

    The fundamental insight and the technological & environmental relevance of metastable systems have given a strong impetus from the last decade development of extreme pressures experimental techniques, from the GPa region to the challenging negative pressures domain. The ultimate verification of theoretical models and reliable equations for portraying basic properties for such systems seems to be possible only when including temperature and pressure paths. This volume presents a set of papers related to novel findings on the glass transition phenomenon, phase transitions in liquid crystals, critical mixtures, bioliquids, geophysical system which can reveal surprising "secret" features only when using extreme pressures. This can be illustrated by the link between colloidal and molecular glassformers, the universal onset of the non-trivial dynamics in glasses, demistification of the secondary relaxation or novel findings associated with liquid - liquid near critical transitions in critical mixture, liquid cr...

  6. Normal pressure hydrocephalus

    Science.gov (United States)

    Hydrocephalus - occult; Hydrocephalus - idiopathic; Hydrocephalus - adult; Hydrocephalus - communicating; Dementia - hydrocephalus; NPH ... Ferri FF. Normal pressure hydrocephalus. In: Ferri FF, ed. ... Elsevier; 2016:chap 648. Rosenberg GA. Brain edema and disorders ...

  7. Deuterium High Pressure Target

    CERN Document Server

    Perevozchikov, V; Vinogradov, Yu I; Vikharev, M D; Ganchuk, N S; Golubkov, A N; Grishenchkin, S K; Demin, A M; Demin, D L; Zinov, V G; Kononenko, A A; Lobanov, V N; Malkov, I L; Yukhimchuk, S A

    2001-01-01

    The design of the deuterium high-pressure target is presented. The target having volume of 76 cm^3 serves to provide the experimental research of muon catalyzed fusion reactions in ultra-pure deuterium in the temperature range 80-800 K under pressures of up to 150 MPa. The operation of the main systems of the target is described: generation and purification of deuterium gas, refrigeration, heating, evacuation, automated control system and data collection system.

  8. Deuterium high pressure target

    International Nuclear Information System (INIS)

    The design of the deuterium high-pressure target is presented. The target having volume of 76 cm3 serves to provide the experimental research of muon catalyzed fusion reactions in ultra-pure deuterium in the temperature range 80-800 K under pressures of up to 150 MPa. The operation of the main systems of the target is described: generation and purification of deuterium gas, refrigeration, heating, evacuation, automated control system and data collection system

  9. Pulse Pressure in Clinical Practice

    Directory of Open Access Journals (Sweden)

    Jiri Parenica

    2012-02-01

    Full Text Available The review presents basic information about the pulse pressure. The variables related to pulse pressure are briefly explained - arterial stiffness, arterial compliance, pulse wave velocity, pulse pressure amplification and augmentation index. We present some recent trials and observational studies that show the importance of pulse pressure in clinical practice. Briefly the possibilities of influencing the pulse pressure are discussed.

  10. Home monitoring of blood pressure

    OpenAIRE

    McGrath, Barry P

    2015-01-01

    Home blood pressure monitoring is the self-measurement of blood pressure by patients. In the diagnosis and management of high blood pressure it is complementary to 24-hour ambulatory blood pressure monitoring and clinic blood pressure measurements. Home monitoring can also help to identify white-coat and masked hypertension.

  11. Blood Pressure vs. Heart Rate

    Science.gov (United States)

    ... Pressure High Blood Pressure Tools & Resources Stroke More Blood Pressure vs. Heart Rate Updated:Aug 30,2016 Blood ... was last reviewed on 08/04/2014. High Blood Pressure • Home • About High Blood Pressure (HBP) Introduction What ...

  12. Tevatron quench pressure measurement

    International Nuclear Information System (INIS)

    The upcoming lower temperature/higher energy upgrade to the Fermilab Tevatron accelerator has raised questions concerning peak pressures during magnet system quenches. An experiment was performed to measure the pressure versus time at various quench energies in several devices in the Tevatron. A smaller study also looked at the temperature and mass flow rate versus time. Data was captured in a PC based circular buffer. The buffer captured ten seconds of data at 250 Hz for up to eight channels. Quenches ranging from 400 GeV to 1000 GeV were investigated. Peak pressures of 1.24 MPa (180 psia) were measured at 1000 GeV. Peak pressure increased linearly with quench energy up to 950 GeV, where it flattened off. Likewise, the time to reach peak pressure decreased linearly until 900 GeV, where it flattened off at 280 ms. The process appears to become heat transfer limited at about 900 GeV. This results in reasonable peak quench pressures at the expense of the coil reaching higher peak temperatures (not measured). The existing cryostats and relieving systems in the Tevatron will be sufficient for the new low temperature upgrade

  13. Diagnosis of High Blood Pressure

    Medline Plus

    Full Text Available ... providers diagnose high blood pressure when blood pressure readings are consistently 140/90 mmHg or above. Confirming ... minutes before the test. To track blood pressure readings over a period of time, the health care ...

  14. Diagnosis of High Blood Pressure

    Medline Plus

    Full Text Available ... of High Blood Pressure For most patients, health care providers diagnose high blood pressure when blood pressure ... painless and can be done in a health care provider’s office or clinic. To prepare for the ...

  15. What Causes High Blood Pressure?

    Science.gov (United States)

    ... whether imbalances in this system cause high blood pressure. Blood Vessel Structure and Function Changes in the structure ... can affect blood pressure. Genetic Causes of High Blood Pressure Much of the understanding of the body systems ...

  16. Prevention of High Blood Pressure

    Science.gov (United States)

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

  17. Medications for High Blood Pressure

    Science.gov (United States)

    ... dangerous as elevations of both systolic and diastolic pressure. Blood pressure is elevated for two main reasons: too ... and Angiotensin II receptor blockers (ARBs), reduce blood pressure by relaxing blood vessels Beta blockers, which also cause the heart ...

  18. Pressure tube type reactor

    International Nuclear Information System (INIS)

    Heretofore, a pressure tube type reactor has a problem in that the evaluation for the reactor core performance is complicate and no sufficient consideration is made for the economical property, to increase the size of a calandria tank and make the cost expensive. Then, in the present invention, the inner diameter of a pressure tube is set to greater than 50% of the lattice gap in a square lattice like arrangement, and the difference between the inner and the outer diameters of the calandria tube is set smaller than 20% of the lattice gap. Further, the inner diameter of the pressure tube is set to greater than 40% and the difference between the inner and the outer diameters of the calandria tube is set smaller than 30% of the lattice gap in a triangle lattice arrangement. Then, heavy water-to-fuel volume ratio can be determined appropriately and the value for the coolant void coefficient is made more negative side, to improve the self controllability inherent to the reactor. In particular, when 72 to 90 fuel rods are arranged per one pressure tube, the power density per one fuel rod is can be increased by about twice. Accordingly, the number of the pressure tubes can be reduced about to one-half, thereby enabling to remarkably decrease the diameter of the reactor core and to reduce the size of the calandria, which is economical. (N.H.)

  19. Reactor pressure boundary materials

    International Nuclear Information System (INIS)

    With a long-term operation of nuclear power plants, the component materials are degraded under severe reactor conditions such as neutron irradiation, high temperature, high pressure and corrosive environment. It is necessary to establish the reliable and practical technologies for improving and developing the component materials and for evaluating the mechanical properties. Especially, it is very important to investigate the technologies for reactor pressure boundary materials such as reactor vessel and pipings in accordance with their critical roles. Therefore, this study was focused on developing and advancing the microstructural/micro-mechanical evaluation technologies, and on evaluating the neutron irradiation characteristics and radiation effects analysis technology of the reactor pressure boundary materials, and also on establishing a basis of nuclear material property database

  20. The pressure suppression system

    International Nuclear Information System (INIS)

    Nuclear plants with boiling water reactors have a safety containment with a pressure suppression system (PSS). Proceeding on significant self-developments, today the three PSS-lines of General Electric Co. (GE), Kraftwerk Union AG (KWU) and ASEA-ATOM are predominant, which are currently represented by the MARK III type, the KWU type 72 and the BWR 75 containment. In addition, there are special developments for the nuclear ship propulsion and for the pressurized water reactors in the Soviet Union. Key design values of the PSS allow a first valuation of its loads during a hypothetical loss-of-coolant accident. (orig.)

  1. A life under pressure

    DEFF Research Database (Denmark)

    Jacobsen, Jens Christian Brings; von Holstein-Rathlou, Niels-Henrik

    2012-01-01

    Microvessels live 'a life under pressure' in several ways. In a literal sense, vessels of the microcirculation are exposed to high levels of stress caused primarily by the intravascular pressure head. In a figurative sense, the individual vessel and the microvascular network as a whole must...... stress component has a huge impact on the state of the vascular wall. It is involved as a unifying factor on vastly different timescales in processes as diverse as acute regulation of vessel diameter, structural vessel remodelling and growth or atrophy of the vascular wall. The aim of this Mini...

  2. Diagnostics of pressure ulcer risk and pressure ulcers

    OpenAIRE

    Kottner, Jan

    2011-01-01

    Pressure ulcers are serious health problems and they develop in every healthcare setting. Pressure ulcer risk scales aim to support practitioners in determining individual pressure ulcer risk and in starting preventive activities. Study results indicate validity problems inherent in pressure ulcer risk scale scores. Since risk scores are too imprecise for individual clinical decision making, it is questionable whether the standardized pressure ulcer risk assessments improve resident and patie...

  3. Intracranial Pressure Monitoring

    DEFF Research Database (Denmark)

    Raboel, P H; Bartek, J; Andresen, M;

    2012-01-01

    Monitoring of intracranial pressure (ICP) has been used for decades in the fields of neurosurgery and neurology. There are multiple techniques: invasive as well as noninvasive. This paper aims to provide an overview of the advantages and disadvantages of the most common and well-known methods...

  4. Farmers under pressure

    DEFF Research Database (Denmark)

    Andrade, Stefan Bastholm; Anneberg, Inger

    2013-01-01

    of them face severe financial difficulties, divorce and psychiatric problems, which are connected to an increased risk of being convicted for the neglect of farm animals. The narratives bring forward themes of pressure related to financial trouble, technological break down, family problems, stress...

  5. Blood pressure and atherosclerosis

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    2010319 Effects of combined application of Xuezhikang capsule with hypotensive drugs on arterial compliance and smoothness of the dynamic blood pressure. ZHU Zongtao(朱宗涛),et al. Dept Cardiol, Centr People’s Hosp, Tengzhou 277500.Chin J Integr Tradit & West Med 2010;30

  6. PRESSURE-RESISTANT VESSEL

    NARCIS (Netherlands)

    Beukers, A.; De Jong, T.

    1997-01-01

    Abstract of WO 9717570 (A1) The invention is directed to a wheel-shaped pressure-resistant vessel for gaseous, liquid or liquefied material having a substantially rigid shape, said vessel comprising a substantially continuous shell of a fiber-reinforced resin having a central opening, an inner l

  7. Preventing Pressure Sores

    Medline Plus

    Full Text Available ... how is it treated? What's the most important thing to do to prevent pressure sores? A spinal cord injury affects the entire family FacingDisability is designed to provide Internet-based information and support for people with spinal ...

  8. Preventing pressure ulcers

    Science.gov (United States)

    ... or gel seat cushion that fits your wheelchair. Natural sheepskin pads are also helpful to reduce pressure on the skin. DO NOT sit on a donut-shaped cushions. You or your caregiver should shift your weight in your wheelchair every ...

  9. Diagnosis of High Blood Pressure

    Medline Plus

    Full Text Available ... pressure. Using the results of your blood pressure test, your health care provider will diagnose prehypertension or high blood pressure ... same age, gender, and height . Once your health care provider ... he or she can order additional tests to determine if your blood pressure is due ...

  10. Stroke and High Blood Pressure

    Science.gov (United States)

    ... Pressure Tools & Resources Stroke More Stroke and High Blood Pressure Updated:Jan 6,2015 Stroke is a leading ... heart disease and stroke. Start exploring today ! High Blood Pressure • Home • About High Blood Pressure (HBP) • Why HBP ...

  11. Potassium and High Blood Pressure

    Science.gov (United States)

    ... Pressure Tools & Resources Stroke More Potassium and High Blood Pressure Updated:Mar 1,2016 A diet that includes ... was last reviewed on 08/04/2014. High Blood Pressure • Home • About High Blood Pressure (HBP) • Why HBP ...

  12. Types of Blood Pressure Medications

    Science.gov (United States)

    ... Blood Pressure Tools & Resources Stroke More Types of Blood Pressure Medications Updated:Aug 26,2016 Many medications known ... was last reviewed on 08/04/2014. High Blood Pressure • Home • About High Blood Pressure (HBP) • Why HBP ...

  13. High Blood Pressure and Women

    Science.gov (United States)

    ... High Blood Pressure Tools & Resources Stroke More High Blood Pressure and Women Updated:Aug 13,2014 Many people ... was last reviewed on 08/04/14. High Blood Pressure • Home • About High Blood Pressure (HBP) • Why HBP ...

  14. Myths about High Blood Pressure

    Science.gov (United States)

    ... Pressure Tools & Resources Stroke More Myths About High Blood Pressure Updated:Aug 12,2014 You CAN manage your ... was last reviewed on 08/04/2014. High Blood Pressure • Home • About High Blood Pressure (HBP) Introduction What ...

  15. High Pressure Biomass Gasification

    Energy Technology Data Exchange (ETDEWEB)

    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, similar approach for

  16. High Pressure Biomass Gasification

    Energy Technology Data Exchange (ETDEWEB)

    Agrawal, Pradeep K [Georgia Tech Research Corporation, Atlanta, GA (United States)

    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

  17. High pressure gas metering project

    International Nuclear Information System (INIS)

    The initial research and development of a system that uses high pressure helium gas to pressurize vessels over a wide range of pressurization rates, vessel volumes, and maximum test pressures are described. A method of controlling the mass flow rate in a test vessel was developed by using the pressure difference across a capillary tube. The mass flow rate is related to the pressurization rate through a real gas equation of state. The resulting mass flow equation is then used in a control algorithm. Plots of two typical pressurization tests run on a manually operated system are included

  18. Negative pressure device for intra-abdominal pressure reduction

    Energy Technology Data Exchange (ETDEWEB)

    David, M; Geido, D; Pracca, F; Sanchez, G; Simini, F; Zoppolo, C [Nucleo de Ingenierfa Biomedica, Universidad de la Republica O. del Uruguay, Hospital de ClInicas, Av. Italia S/N, 11600, Montevideo (Uruguay)

    2007-11-15

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

  19. Idiopathic Normal Pressure Hydrocephalus

    Directory of Open Access Journals (Sweden)

    Basant R. Nassar BS

    2016-04-01

    Full Text Available 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.

  20. High pressure furnace

    Science.gov (United States)

    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.

  1. High pressure oxygen furnace

    Science.gov (United States)

    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.

  2. Nozzle limit pressure

    International Nuclear Information System (INIS)

    A brief description of the static method aiming to determined the collapse load in a structure of elastic-plastic material is given. This methodology together with the Finite Element Method in the field approximation, leads to a problem of minimizing a linear function with linear constraints. The application of this technique to axissymmetrical shells submmited to axissymmetric loads is analyzed; the numerical application is done for nozzles in pipelines and pressure vessels joints. (E.G.)

  3. High pressure storage vessel

    Science.gov (United States)

    Liu, Qiang

    2013-08-27

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

  4. Pressure Garment Subsystem Roadmap

    Science.gov (United States)

    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.

  5. Hyperbaric Pressure Control System

    OpenAIRE

    Berg, Brian; Skjørten, Anders; Nicolaysen, Jonas; Skarseth, Thor Ove; Carlstedt, Jonas

    2015-01-01

    The requirement specification for the project where changed from delivery of a fully working product to contain only the design of this system due to long lead times on some of the high-pressure hydraulic parts. Three of the students where already working for FMC before project start, where two of them had experience with hydraulic Subsea Systems. Our project model where changed during the project. We started out with a Waterfall model and ended up with an Evolutionary model

  6. Low-pressure

    Energy Technology Data Exchange (ETDEWEB)

    Baker, Richard [Membrane Technology And Research, Inc., Newark, CA (United States); Kniep, Jay [Membrane Technology And Research, Inc., Newark, CA (United States); Hao, Pingjiao [Membrane Technology And Research, Inc., Newark, CA (United States); Chan, Chi Cheng [Membrane Technology And Research, Inc., Newark, CA (United States); Nguyen, Vincent [Membrane Technology And Research, Inc., Newark, CA (United States); Huang, Ivy [Membrane Technology And Research, Inc., Newark, CA (United States); Amo, Karl [Membrane Technology And Research, Inc., Newark, CA (United States); Freeman, Brice [Membrane Technology And Research, Inc., Newark, CA (United States); Fulton, Don [Membrane Technology And Research, Inc., Newark, CA (United States); Ly, Jennifer [Membrane Technology And Research, Inc., Newark, CA (United States); Lipscomb, Glenn [Membrane Technology And Research, Inc., Newark, CA (United States); Lou, Yuecun [Membrane Technology And Research, Inc., Newark, CA (United States); Gogar, Ravikumar [Membrane Technology And Research, Inc., Newark, CA (United States)

    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.

  7. Pressure Controlled Chemical Gardens.

    Science.gov (United States)

    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. PMID:27266993

  8. INTRACRANIAL PRESSURE MONITORING TECHNIQUE

    Directory of Open Access Journals (Sweden)

    Ida Bagus Adi Kayana

    2013-03-01

    Full Text Available Head injury is the most significant cause of increased morbidity and mortality. An estimated 1.4 million head injuries occur each year, with and more than 1.1 million come to the Emergency Unit. On each patient head injury, an increase in intracranial pressure (ICP related to poor outcomes and aggressive therapy to increased ICP can improve the outcomes. ICP monitoring is the most widely used because of the prevention and control of ICP as well as maintain the pressure increase perfusion of cerebral (Cerebral Perfusion Pressure/CPP is the basic purpose of handling head injury. There are two methods of monitoring ICP that is an invasive methods (directly and non-invasive techniques (indirectly. The method commonly used, namely intraventricular and intraparenkimal (microtransducer sensor because it is more accurate but keep attention to the existence of the risk of bleeding and infection resulting from installation. Monitoring of ICT can determine the actions that avoid further brain injury, which can be lethal and irreversibel.

  9. Calculation of downhole pressure and optimization design of construction parameters for gas lift and foam combined technology%气举-泡排组合工艺井底压力计算及施工参数优化设计

    Institute of Scientific and Technical Information of China (English)

    汪来潮; 熊钰; 陈霖; 李娟; 黄雨

    2012-01-01

    In view of the model that the mixtures in the wellbore implementing gas lift and foam drainage combined technology is composed of foam and free gas out of foam which get off from each other, this paper introduced the parameter“foam retention rate”and then derived a series of formulas to calculate the density of foam,“foam retention rate”and the density of wellbore mixtures, so as to determine wellbore pressure profile and calculate bottom hole pressure. This paper also verified the feasibility of the calcula-tion method by the calculation examples and results comparison to provide guidance for the optimization design of implementation parameters. The calculation method only has to calculate with a computer grogram to solve the complex work of pressure testing and improve the economics.%基于气举-泡排组合工艺井井筒中的混合流体是由泡沫(或泡沫团)与泡沫外气体组成并相互滑脱这一模型,引入持泡率这一参数,相继推导了确定泡沫密度、持泡率和混合流体密度等主要参数的计算公式,从而可以确定井筒压力剖面并计算井底流压。通过实例计算与对比,验证了计算方法的可行性,为气举-泡排组合工艺的施工参数的优化设计提供指导。气举-泡排组合工艺的井筒压力剖面计算方法,只需借助于计算机程序,节约了复杂的测压作业,提高了经济效益。

  10. Foam drilling in natural gas hydrate

    Directory of Open Access Journals (Sweden)

    Wei Na

    2015-01-01

    Full Text Available The key problem of foam drilling in natural gas hydrate is prediction of characteristic parameters of bottom hole. The simulation shows that when the well depth increases, the foam mass number reduces and the pressure increases. At the same depth, pressure in drill string is always higher than annulus. The research findings provide theoretical basis for safety control.

  11. Pressure Drop in Cyclone Separator at High Pressure

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    For the design of pressurized circulating fluidized beds, experiments were conducted in a small cyclone with 120 mm in diameter and 300 mm in height at high pressures and at atmospheric temperatures. Influence of air leakage from the stand pipe into the cyclone was specially focused. A semi-empirical model was developed for the predic tion of the pressure drop of the cyclone separator at different operate pressures with the effect of air leakage and inlet solid loading. The operate pressure, air leakage and inlet solid loading act as significant roles in cyclone pressure drop. The pressure drop increases with the increasing of pressure and decreases with the increasing of the flow rate of air leakage from the standpipe and with the increasing of the inlet solid loading.

  12. Measurement of Strong Shock Pressure

    Directory of Open Access Journals (Sweden)

    Hajime Takada

    1997-01-01

    Full Text Available This paper deals with measurement of a strong shock pressure like an imploding detonation of over 1 GPa which cannot be measured directly with currently available commercial pressure transducers. After the transfer functions of three kinds of materials were measured using a shock tube, Teflon was selected as a shock absorber. As an example of pressure beyond the limit of the pressure transducer, we tried to measure pressure at the center of an imploding detonation. From this measurement, we could estimate the pressure peak of about 1.7 GPa.

  13. Ashcroft Pressure Switch Monitor for Low SCHe Purge Pressure

    Energy Technology Data Exchange (ETDEWEB)

    VAN KATWIJK, C.

    2000-06-21

    These 0-15 psig pressure switches are located in the SCHe helium purge lines after PCV-5*23 and before PCV-5*27. The pressure switches monitor the pressure being maintained between the two PCVs and actuate on low pressure of 15 psig. This design is used for each of the SCHe supply lines (4). Electronic output signal is NON-SAFETY (GS).

  14. Reconstruction of brachial pressure from finger arterial pressure during orthostasis

    DEFF Research Database (Denmark)

    Bogert, Lysander W J; Harms, Mark P M; Pott, Frank;

    2004-01-01

    In patients with recurrent syncope, monitoring of intra-arterial pressure during orthostatic stress testing is recommended because of the potentially sudden and rapid development of hypotension. Replacing brachial arterial pressure (BAP) by the non-invasively obtained finger arterial pressure (Fin...

  15. Blood Pressure Matters: Keep Hypertension in Check

    Science.gov (United States)

    ... cuff, or an automatic device may measure the pressure. Blood pressure is given as 2 numbers. The first ... described above. High Blood Pressure NIHSeniorHealth: High Blood Pressure High Blood Pressure and Kidney Disease Heart and Vascular Diseases ...

  16. Questions and Answers about High Blood Pressure

    Science.gov (United States)

    ... Blood Pressure Page Content What is high blood pressure? Blood pressure is the force of blood against the ... do I know if I have high blood pressure? High blood pressure is often called "the silent killer" because ...

  17. High blood pressure and diet

    Science.gov (United States)

    ... this page: //medlineplus.gov/ency/article/007483.htm High blood pressure and diet To use the sharing features on ... diet is a proven way to help control high blood pressure . These changes can also help you lose weight ...

  18. Diagnosis of High Blood Pressure

    Medline Plus

    Full Text Available ... 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 ...

  19. Diagnosis of High Blood Pressure

    Medline Plus

    Full Text Available ... track blood pressure readings over a period of time, the health care provider may ask you to ... the office on different days and at different times to take your blood pressure. The health care ...

  20. High pressure diffraction at ISIS

    International Nuclear Information System (INIS)

    The development of the high pressure diffraction programme at ISIS is reviewed. Along with general accounts of the technique and the pressure cells used, examples of science carried out in this field are given. (author)

  1. Human gallbladder pressure and volume

    DEFF Research Database (Denmark)

    Borly, L; Højgaard, L; Grønvall, S;

    1996-01-01

    influenced by respiration (n = 8) and the pressure seems to be higher in the sitting position than in the supine position (n = 5). Cystic duct opening pressure was 10.4, 11.2 and 16.8 mmHg (n = 3). Pressure-volume responses showed that the GB up to a certain volume could accommodate increases in intraluminal...... volume with only slight changes in intraluminal pressure (n = 4). Except for the zero drift, this piece of equipment seemed to fulfil the requirements of being able to measure pressure in the GB. In vivo measurements showed a good clinical reproducibility of the method, and also that respiration...... and patient posture influenced the pressure measurements. Further, a GB pressure-volume relationship was demonstrated, and the possibility of a cystic duct opening pressure was described....

  2. Genes That Influence Blood Pressure

    Science.gov (United States)

    ... Research Matters NIH Research Matters September 26, 2011 Genes that Influence Blood Pressure In one of the ... 16 previously unknown variations. Six were found in genes already suspected of regulating blood pressure. The remaining ...

  3. Mediator-Generated Pressure Tactics

    Science.gov (United States)

    Byrnes, Joseph F.

    1978-01-01

    Two examples of bluff pressures (as opposed to real pressures) used by mediators to effect contract settlements are presented, along with advice to negotiators on avoiding or minimizing such tactics. (Author/IRT)

  4. High Blood Pressure in Pregnancy

    Science.gov (United States)

    ... 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 ...

  5. Diagnosis of High Blood Pressure

    Medline Plus

    Full Text Available ... Clinical Trials What Are Clinical Trials? Children & Clinical Studies NHLBI ... providers diagnose high blood pressure when blood pressure readings are consistently 140/90 mmHg or above. Confirming High Blood ...

  6. Diagnosis of High Blood Pressure

    Science.gov (United States)

    ... Clinical Trials What Are Clinical Trials? Children & Clinical Studies NHLBI ... providers diagnose high blood pressure when blood pressure readings are consistently 140/90 mmHg or above. Confirming High Blood ...

  7. INTRACRANIAL PRESSURE MONITORING

    Directory of Open Access Journals (Sweden)

    Retno Widiyanthi

    2013-07-01

    Full Text Available Normal 0 false false false EN-US X-NONE X-NONE Intracranial pressure is total of pressure that is produced by brain, blood, and cerebrospinal fluid/CSF in the tight cranial space. As a respon to intracranial pressure increasing, compensation begin by movement of CSF from ventricle to cerebral subarachnoidal space, and increase the absorption of CSF. Increasing of ICP usually caused by increasing of brain volume (cerebral oedem, blood (intracranial bleeding, space occupying lesion, or CSF (hidrocephalus. Indication in ICP monitoring can be seen from : neurological criteria, abnormal CT-scan result when admission, normal CT-scan result, but had more two risk factors. According to the procedure that must be done, there are two methods in ICP monitoring: invasive ICP monitoring methodes and non-invasive measuring method. Increasing of ICP will decrease the compliance of brain, pulsation of artery more clearly, and the component of vein is lost. /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin:0in; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Calibri","sans-serif"; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-fareast-font-family:"Times New Roman"; mso-fareast-theme-font:minor-fareast; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin; mso-bidi-font-family:"Times New Roman"; mso-bidi-theme-font:minor-bidi;}

  8. Unibody Composite Pressurized Structure

    Science.gov (United States)

    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.

  9. Pressure difference receiving ears

    DEFF Research Database (Denmark)

    Michelsen, Axel; Larsen, Ole Næsbye

    2007-01-01

    of such pressure difference receiving ears have been hampered by lack of suitable experimental methods. In this review, we review the methods for collecting reliable data on the binaural directional cues at the eardrums, on how the eardrum vibrations depend on the direction of sound incidence, and on how sound...... waves behave in the air spaces leading to the interior surfaces of eardrums. A linear mathematical model with well-defined inputs is used for exploring how the directionality varies with the binaural directional cues and the amplitude and phase gain of the sound pathway to the inner surface...

  10. Pressure pain sensitivity

    DEFF Research Database (Denmark)

    Bergmann, Natasha; Ballegaard, Søren; Holmager, Pernille;

    2013-01-01

    induce hyperalgesia.The aim of the present study was to evaluate hyperalgesia by pressure pain sensitivity (PPS) in patients with IHD, and compare PPS to questionnaires measuring depressive symptoms, reduced psychological wellbeing, and QOL as markers of stress. Design. A cross-sectional study of 361...... subjects with IHD. Methods. PPS was measured on the sternum, and compared to the questionnaires: Clinical stress symptoms score (CSS), Major Depression Inventory (MDI), WHO-5 Wellbeing Index, and SF-36 QOL score. Results. PPS correlated to CSS (r = 0.20, p <0.001), MDI (r = 0.14, p = 0.02), SF-36 mental...

  11. Saltstone Osmotic Pressure

    Energy Technology Data Exchange (ETDEWEB)

    Nichols, Ralph L. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Dixon, Kenneth L. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRN

    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.

  12. Increasing Inflationary Pressure

    Institute of Scientific and Technical Information of China (English)

    Guo Yan

    2008-01-01

    @@ China's CPI rose to 8.7 percent in February after hitting 7.1 percent in January,creating a 12-year high,the National Bureau of Statistics said.The figure exceeded market expectations,as the Bank of China,the country's secondlargest lender,had predicted a rise of only 8.3 percent.The Consumer Price Index (CPI)is the main gauge of inflation,andthe high CPI over the last two months has put pressure on the government to take action to curb the price increases,and added even more diffculty to the task of reining in this year's inflation rate.

  13. Tending to Internal Pressure

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    As China integrates into the world economy,its economic sustainability and industrial health become more vulnerable to external factors.While China’s grain security comes under intense pressure,thefinancialsectoris confrontedwithloomingrisks.Thecountry’s manufacturingindustryleads the world,but its competitiveness is impeded by a lack of high-end production.Many economists and experts discussed these issues at the 2011 China Economic Security Forum,recently held by the University of International Business and Economics in Beijing.Edited excerpts follow:

  14. Barotrauma: Tooth Under Pressure.

    Science.gov (United States)

    Kumar, Satheesh; Kumar, Preeti Satheesh; John, Jins; Patel, Ruchi

    2015-11-01

    With the growing number of air passengers, flight attendants, leisure pilots, as well as military and airline pilots, dentists may encounter physiological and pathological phenomena precipitated by high altitude. With the introduction of the self-contained breathing apparatus (SCUBA), many of these manifestations caused by changes in atmospheric pressure were reported in association with diving as well. Limited literature exists on this subject. Hence, this article aims to review literature concerning the classification, etiology and manifestations of barodontalgia, as well as important clinical considerations for its management.

  15. Murata - A Pressure Sensor Based Blood Pressure : Preliminary Reliability Study

    OpenAIRE

    Nummelin, Elina

    2015-01-01

    The purpose of the study was to determine the reliability of a blood pressure sensor developed by Murata as a blood pressure monitoring tool compared to an automatic blood pressure monitor, Omron M6. Blood pressure is one of the principal vital signs and is utilized for monitoring both short-term and long-term health of the cardiovascular system and thereby the health of the patient. Therefore there is a need for a non-invasive blood pressure monitor for accurate, continuous and comfortab...

  16. Diagnosis of High Blood Pressure

    Medline Plus

    Full Text Available ... Diagnosis of High Blood Pressure For most patients, health care providers diagnose high blood pressure when blood pressure ... and painless and can be done in a health care provider’s office or clinic. To prepare for the ...

  17. Gas Pressure-Drop Experiment

    Science.gov (United States)

    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…

  18. Instrument measures dynamic pressure fluctuations

    Science.gov (United States)

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

    1977-01-01

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

  19. Diagnosis of High Blood Pressure

    Medline Plus

    Full Text Available ... page from the NHLBI on Twitter. Diagnosis of High Blood Pressure For most patients, health care providers diagnose high ... are consistently 140/90 mmHg or above. Confirming High Blood Pressure A blood pressure test is easy and painless ...

  20. Pressure Safety: Advanced Live 11459

    Energy Technology Data Exchange (ETDEWEB)

    Glass, George [Los Alamos National Laboratory

    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.

  1. Living with High Blood Pressure

    Science.gov (United States)

    ... from the NHLBI on Twitter. Living With High Blood Pressure If you have high blood pressure, the best thing to do is to talk ... care provider and take steps to control your blood pressure by making healthy lifestyle changes and taking medications, ...

  2. Pressure transients in pipeline systems

    DEFF Research Database (Denmark)

    Voigt, Kristian

    1998-01-01

    This text is to give an overview of the necessary background to do investigation of pressure transients via simulations. It will describe briefly the Method of Characteristics which is the defacto standard for simulating pressure transients. Much of the text has been adopted from the book Pressur...

  3. Abnormal pressure in hydrocarbon environments

    Science.gov (United States)

    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.

  4. Pressure Effect on Extensional Viscosity

    DEFF Research Database (Denmark)

    Christensen, Jens Horslund; Kjær, Erik Michael

    1999-01-01

    The primary object of these experiments was to investigate the influence of hydrostatic pressure on entrance flow. The effect of pressure on shear and extensional viscosity was evaluated using an axis symmetric capillary and a slit die where the hydrostatic pressure was raised with valves. The ex...

  5. The Myth of Peer Pressure.

    Science.gov (United States)

    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)

  6. Pressure polymerization of polyester

    Science.gov (United States)

    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.

  7. Transglottal pressures in professional singing.

    Science.gov (United States)

    Schutte, H K; Miller, D G

    1986-01-01

    Using high-frequency miniature pressure transducers, direct measurements of sub- and supra-glottal pressure are taken on two sopranos singing high notes, in a range where F1 is close to F0. When the peak in supraglottal pressure occurs well into the open phase of the glottal cycle, the instantaneous transglottal pressure approaches zero. When this peak occurs later in one of the subjects as a feature of the vibrato modulation, the transglottal pressure even drops appreciably below zero. The implications of these findings for the glottal volume velocity waveform, as well as for the singer's experience of the second "passaggio" point, are discussed. PMID:3751533

  8. ORANGE JUICE AND BLOOD PRESSURE

    Directory of Open Access Journals (Sweden)

    M. F. VALIM

    2009-01-01

    Full Text Available

    Blood pressure is the force of blood against artery walls. It is measured in millimeters of mercury (mm Hg and recorded as two numbers: systolic pressure (as the heart contracts over diastolic pressure (as the heart relaxes between beats. High blood pressure (hypertension is defined as chronically elevated high blood pressure, with systolic blood pressure (SBP of 140 mm Hg or greater, and diastolic blood pressure (DBP of 90 mm Hg or greater. High blood pressure (HBP, smoking, abnormal blood lipid levels, obesity and diabetes are risk factors for coronary heart disease, the leading cause of death in the US. Lifestyle modifications such as engaging in regular physical activity, quitting smoking and eating a healthy diet (limiting intake of saturated fat and sodium and increasing consumption of fiber, fruits and vegetables are advocated for the prevention, treatment, and control of HBP. As multiple factors influence blood pressure, the effects of each factor are typically modest, particularly in normotensive subjects, yet the combined effects can be substantial. Nutrition plays an important role in influencing blood pressure. Orange juice should be included as part of any low sodium diet and/or any blood pressure reducing eating plan, as it is sodium free, fat-free and can help meet recommended levels of potassium intake that may contribute to lower BP.

  9. From Pressures to Impacts

    DEFF Research Database (Denmark)

    Hauschild, Michael Zwicky

    2006-01-01

    Life cycle assessment (LCA) has been developed as a tool for assessment of the environmental impacts which are caused by the pressures from products or systems, viewed in a life cycle perspective, i.e. covering all stages of the life cycle of the product or system from the extraction of raw...... is defined, Inventory analysis where data for the physical flows to and from all processes in the life cycle is collected and related to the functional unit, Impact assessment, where the physical flows are translated into impacts on the environment and resource base, and Interpretation where the outcomes...... of the earlier phases are interpreted in relation to the goal of the LCA. LCA is typically used for comparisons, and in order to facilitate the comparison of the rather diverse environmental impacts which are comprised by the Life Cycle Impact Assessment (LCIA) methodology, procedures have been developed...

  10. Partial pressure gauges

    CERN Document Server

    Peter, G J

    2007-01-01

    The determination of partial pressures in vacuum systems is usually performed by mass spectrometers. The most common type is the QMS. Quadrupole mass spectrometers were developed decades ago and have been used by vacuum specialists as a diagnostic tool since then. In the first part of the paper the principles of these mass spectrometers are briefly reviewed together with the key features of the instruments. This is necessary to operate these instruments. In the second part the boundary conditions which arise from the application as residual gas analyser in UHV/XHV plants are described. These lead to special versions of mass spectrometers. Results obtained with these instruments and typical artefacts in mass spectra obtained in the UHV are discussed.

  11. Blood pressure and atherosclerosis

    Institute of Scientific and Technical Information of China (English)

    1993-01-01

    930082 Clinical administration of atrial natri-uretic factor in reno-vascular hypertension.ZHANG Weiguo(张卫国),et al.Cardiovasc In-stit & Fuwai Hosp,CAMS,Beijing.Chin Cir J1992;7(5):450-452.In order to evaluate the effects of atrial natri-uretic factor(ANF)on patients with reno-vas-cular hypertension,α-hANF(0.025μg/kg/min×60min)was administered to 7 patients byi.v.drip..The renin-angiotensin-aldosteronesystem,plasma catecholamine and arginine va-sopressin were suppressed with diuresis and na-triuresis and lowering of blood pressure.The

  12. Effects of pressure waves

    Science.gov (United States)

    1977-01-01

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

  13. Estimation of vapour pressure and partial pressure of subliming compounds by low-pressure thermogravimetry

    Indian Academy of Sciences (India)

    G V Kunte; Ujwala Ail; P K Ajikumar; A K Tyagi; S A Shivashankar; A M Umarji

    2011-12-01

    A method for the estimation of vapour pressure and partial pressure of subliming compounds under reduced pressure, using rising temperature thermogravimetry, is described in this paper. The method is based on our recently developed procedure to estimate the vapour pressure from ambient pressure thermogravimetric data using Langmuir equation. Using benzoic acid as the calibration standard, vapour pressure–temperature curves are calculated at 80, 160 and 1000 mbar for salicylic acid and vanadyl bis-2,4-pentanedionate, a precursor used for chemical vapour deposition of vanadium oxides. Using a modification of the Langmuir equation, the partial pressure of these materials at different total pressures is also determined as a function of temperature. Such data can be useful for the deposition of multi-metal oxide thin films or doped thin films by chemical vapour deposition (CVD).

  14. Steam Oxidation at High Pressure

    Energy Technology Data Exchange (ETDEWEB)

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

    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.

  15. Pressure sensors for petroleum wells

    International Nuclear Information System (INIS)

    A patent is claimed for a pressure sensor to be used in petroleum wells. Measurements can be performed under extreme temperature and pressure conditions. The system consists of a cell, containing an extensometric circuit, placed in a container and in contact with the pressure to be measured. The cell is formed by two sapphire half-shells. Their crystallographic orientation is chosen in order to obtain isotropy of stresses. The sensor is nearly independent from temperature fluctuations

  16. Pressures Detector Calibration and Measurement

    CERN Document Server

    AUTHOR|(CDS)2156315

    2016-01-01

    This is report of my first and second projects (of 3) in NA61. I did data taking and analysis in order to do calibration of pressure detectors and verified it. I analyzed the data by ROOT software using the C ++ programming language. The first part of my project was determination of calibration factor of pressure sensors. Based on that result, I examined the relation between pressure drop, gas flow rate of in paper filter and its diameter.

  17. Neutron scattering at high pressure

    OpenAIRE

    Mcwhan, D.B.

    1984-01-01

    The techniques to do elastic and inelastic neutron scattering at steady-state and pulsed sources are reviewed. The pressure cells available at most neutron scattering centres are capable of reaching pressures of the order of 5 GPa (50 kbar), and attempts to reach 10 GPa have been made. For elastic scattering, a comparison is made between neutron scattering and X-ray scattering at high pressure using rotating anode or synchrotron sources.

  18. Pressure on Yukos growing

    International Nuclear Information System (INIS)

    The fate of the Russian oil concern Yukos seems to be sealed. The former rising star of the Russian energy firmament seems to be dying under the pressure of local state administration. Tax arrears, the fact that the owner Mikhail Khodorkovsky was jailed and the company placed under forced administration reflects the conflict between business and political interests in Russia. And the conflict also has an impact on Slovakia. In the portfolio of Yukos Finance, the Dutch subsidiary of Yukos, are assets that are very attractive for Russian oil concerns. One of them is the Slovak operator of the Druzba pipeline, Transpetrol. Yukos Finance owns 49% of the company's shares. Last year, the company signed a contract with the Russian oil company Russneft on the sale of the stake for 103 mil. USD. According to a contract signed in 2002 that stipulated the conditions under which the Slovak state sold the Transpetrol shares to Yukos for the next 5 years such a step has to be approved by the Ministry of Economy. The Dutch company can also sell the shares without such an approval but then it has to pay a penalty fine. In such a case Slovakia would get 50% of the original amount, i.e. 37 mil. USD. (author)

  19. Night time blood pressure dip

    Institute of Scientific and Technical Information of China (English)

    Dennis; Bloomfield; Alex; Park

    2015-01-01

    The advent of ambulatory blood pressure monitoring permitted examination of blood pressures during sleep and recognition of the associated circadian fall in pressure during this period. The fall in pressure,called the "dip",is defined as the difference between daytime mean systolic pressure and nighttime mean systolic pressure expressed as a percentage of the day value. Ten percent to 20% is considered normal. Dips less than 10%,referred to as blunted or absent,have been considered as predicting an adverse cardiovascular event. This view and the broader concept that white coat hypertension itself is a forerunner of essential hypertension is disputable. This editorial questions whether mean arterial pressures over many hours accurately represent the systolic load,whether nighttime dipping varies from measure to measure or is a fixed phenomenon,whether the abrupt morning pressure rise is a risk factor or whether none of these issues are as important as the actual night time systolic blood pressure itself. The paper discusses the difference between medicated and nonmedicated white coat hypertensives in regard to the cardiovascular risk and suggests that further work is necessary to consider whether the quality and duration of sleep are important factors.

  20. Risk Factors for High Blood Pressure

    Science.gov (United States)

    ... the NHLBI on Twitter. Risk Factors for High Blood Pressure Anyone can develop high blood pressure; however, age, ... can increase your risk for developing high blood pressure. Age Blood pressure tends to rise with age. About 65 ...

  1. Healthy Blood Pressure: "It's Worth the Effort!"

    Science.gov (United States)

    ... please turn Javascript on. Special Section: Healthy Blood Pressure Healthy Blood Pressure: "It's worth the effort!" Past Issues / Winter 2010 ... Numbers: What They Mean / Treatment: Types of Blood Pressure Medications / Healthy Blood Pressure: "It's worth the effort!" / Keep the Beat ...

  2. High Blood Pressure and Kidney Disease

    Science.gov (United States)

    ... to Remember Clinical Trials What is high blood pressure? Blood pressure is the force of blood pushing against ... filtering units called nephrons. [ Top ] How does high blood pressure affect the kidneys? High blood pressure can damage ...

  3. High Blood Pressure: Medicines to Help You

    Science.gov (United States)

    ... Consumers Consumer Information by Audience For Women High Blood Pressure--Medicines to Help You Share Tweet Linkedin Pin ... is your pressure when your heart relaxes ( diastolic pressure ). High Blood Pressure Medicines Use this guide to help you ...

  4. High Blood Pressure (Hypertension) (For Parents)

    Science.gov (United States)

    ... lead an active, normal life. What Is Blood Pressure? Blood pressure is the force that blood puts on ... and medications. continue Long-Term Effects of High Blood Pressure When someone has high blood pressure, the heart ...

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

    Science.gov (United States)

    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.

  6. Pressurized Lunar Rover (PLR)

    Science.gov (United States)

    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

  7. Liquids at negative pressure

    Science.gov (United States)

    Xiao, C.; Heyes, D. M.; Powles, J. G.

    2005-03-01

    We have further explored the final stages of the collapse of an unstable cavity or bubble using the Molecular Dynamics computer simulation technique. A nanometre sized spherical volume of molecules was removed from a bulk Lennard-Jones liquid, which being mechanically and thermodynamically unstable, proceeded to collapse. The molecules with the highest kinetic energy were the first to enter the initially empty cavity. The temperature of individual molecules inside the cavity, while the density was still typical of a gas, could reach at least an order of magnitude larger than that of the surrounding liquid, e.g., equivalent to 6,000 K for water, which is not unreasonable for the sonoluminescence effect to be seen. During the filling in of the cavity, the average temperature decreased, as the contents thermally equilibrated with the surrounding liquid. The bubble partially filled in, and then proceeded to partially empty again, and so on in an oscillatory manner, with ever decreasing amplitude towards the final uniform liquid state. This recoil effect is predicted by classical hydrodynamic treatments and has been observed in experiment for much larger bubbles. The temperature, density and normal pressure component were resolved as a function of radius from the centre of the bubble at selected times during the collapsing process. The simulations support the view that MD can provide a realistic representation of the final stages of cavity collapse. It does not make assumptions about equation of state and transport coefficients as would be required for a comparable solution of the Navier-Stokes hydrodynamics equations, and is therefore an especially appropriate description for the final stages of the collapse.

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

    CERN Document Server

    Uden, N W A V; Faux, D A; Tanczos, A C; Howlin, B; Dunstan, D J

    2003-01-01

    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-H sub 3 , C-H sub 2 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 pre...

  9. Possible Pressure Effect for Superconductors

    OpenAIRE

    Chu, A. Kwang-Hua

    2004-01-01

    We make an estimate of the possible range of $\\Delta T_c$ induced by high-pressure effects in post-metallic superconductors by using the theory of {\\it extended irreversible/reversible thermodynamics} and Pippard's length scale. The relationship between the increment of the superconducting temperature and the increase of the pressure is parabolic.

  10. High pressure engineering and technology

    International Nuclear Information System (INIS)

    This book contains 10 papers. Some of the titles are: Control of vibration in high pressure piping systems; Hazards and safeguards of high pressure hydraulic fatigue testing; Load, stress and fatigue analysis of threaded end closures; Application of fatigue crack growth to an isostatic press; and Time dependent failure in high strength steels for autoclave service

  11. Diagnosis of High Blood Pressure

    Medline Plus

    Full Text Available ... does not, you should ask for your readings. Blood Pressure Severity and Type Your health care provider usually takes 2–3 ... any other location. Health care providers diagnose this type of high blood pressure by reviewing readings in the office and ...

  12. Diabetes and blood pressure (image)

    Science.gov (United States)

    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 ...

  13. On pressure rise in rockets

    Directory of Open Access Journals (Sweden)

    S. K. Gupta

    1954-07-01

    Full Text Available The phenomenon of pressure rise in rockets has been discussed on the basis of r=CP/Sup/n as the law of burning. An explicit expression for the chamber pressure at any instant has been derived and illustrated by a table and a graph.

  14. Earth Pressure on Tunnel Crown

    DEFF Research Database (Denmark)

    Andersen, Lars

    Two different analyses have been carried out in order to find the vertical earth pressure, or overburden pressure, at the crown of a tunnel going through a dike. Firstly, a hand calculation is performed using a simple dispersion of the stresses over depth. Secondly, the finite‐element program...

  15. Wrinkling of Pressurized Elastic Shells

    KAUST Repository

    Vella, Dominic

    2011-10-01

    We study the formation of localized structures formed by the point loading of an internally pressurized elastic shell. While unpressurized shells (such as a ping-pong ball) buckle into polygonal structures, we show that pressurized shells are subject to a wrinkling instability. We study wrinkling in depth, presenting scaling laws for the critical indentation at which wrinkling occurs and the number of wrinkles formed in terms of the internal pressurization and material properties of the shell. These results are validated by numerical simulations. We show that the evolution of the wrinkle length with increasing indentation can be understood for highly pressurized shells from membrane theory. These results suggest that the position and number of wrinkles may be used in combination to give simple methods for the estimation of the mechanical properties of highly pressurized shells. © 2011 American Physical Society.

  16. Piezoelectric enhancement under negative pressure.

    Science.gov (United States)

    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

  17. Pressurized waterproof case electronic device

    KAUST Repository

    Berumen, Michael L.

    2013-01-31

    A pressurized waterproof case for an electronic device is particularly adapted for fluid-tight containment and operation of a touch-screen electronic device or the like therein at some appreciable water depth. In one example, the case may be formed as an enclosure having an open top panel or face covered by a flexible, transparent membrane or the like for the operation of the touchscreen device within the case. A pressurizing system is provided for the case to pressurize the case and the electronic device therein to slightly greater than ambient in order to prevent the external water pressure from bearing against the transparent membrane and pressing it against the touch screen, thereby precluding operation of the touch screen device within the case. The pressurizing system may include a small gas cartridge or may be provided from an external source.

  18. Pressure rig for repetitive casting

    Science.gov (United States)

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

    1989-01-01

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

  19. Pressure transient in liquid lines

    International Nuclear Information System (INIS)

    The pressure surge that results from a step change of flow in liquid pipelines, commonly known as water hammer, was analyzed by an eigenfunction method. A differential-integral Pressure wave equation and a linearized velocity equation were derived from the equations of mass and momentum conservation. Waveform distortion due to viscous dissipation and pipe-wall elastic expansion is characterized by a dimensionless transmission number K. The pressure surge condition, which is mathematically singular, was used in the solution procedure. The exact solutions from numerical calculation of the differential-integral equation provide a complete Pressure transient in the pipe. The problems are also calculated With the general-purpose computer code COMMIX, which solves the exact mass conservation equation and Navier-Stokes equations. These solutions were compared with published experimental results, and agreement was good. The effect of turbulence on the pressure transient is discussed in the light of COMMIX calculational results

  20. Effects of Shock Pressure on Transition Pressure in Zr

    Institute of Scientific and Technical Information of China (English)

    LI Ying-Hua; ZHANG Lin; CAI Ling-Cang

    2007-01-01

    Measurements of free surface velocity profiles of high-purity Zr samples under shock-wave loading are performed to study the dynamic strength and phase transition parameters. The peak pressure of the compression waves is within the range from 9 to 14 GPa, and the Hugoniot elastic limit is 0.5 GPa. An anomalous structure of shock waves is observed due to the α - ω phase transition in Zr. Shock pressure has effects on transition pressure which increases with increasing compression strength, and the stronger shocks have a lower transit time.

  1. Diet, blood pressure, and multicollinearity.

    Science.gov (United States)

    Reed, D; McGee, D; Yano, K; Hankin, J

    1985-01-01

    Recent reports of an inverse association between dietary calcium intake and hypertension stimulated this analysis of the relationship of blood pressure to more than 20 dietary factors among a group of 8000 Japanese men in Hawaii. Reported intakes of potassium, calcium, protein, and milk were all inversely associated with blood pressure levels when examined one at a time while controlling for other risk factors. Alcohol intake was directly associated with blood pressure, and was treated as a confounding variable in the analysis. The association of potassium intake with blood pressure was relatively stronger than the associations for other nutrients, but the intake of potassium was so highly correlated with intakes of calcium, milk, and protein that it was not statistically possible to identify the independent association of potassium and blood pressure. Calcium intake was strongly correlated with milk and potassium intakes, and only calcium from dairy sources was associated with blood pressure. These data thus indicate that several dietary factors are inversely related to blood pressure levels independently of other risk factors such as age, body mass, and alcohol intake. The high degree of intercorrelation (multicollinearity) among these dietary factors, however, indicates that the independent role of any specific nutrient cannot be conclusively separated from the possible effects of other nutrients in this type of study.

  2. High pressure effects on fruits and vegetables

    OpenAIRE

    Timmermans, R.A.H.; Matser, A.M.

    2016-01-01

    The chapter provides an overview on different high pressure based treatments (high pressure pasteurization, blanching, pressure-assisted thermal processing, pressure-shift freezing and thawing) available for the preservation of fruits and vegetable products and extending their shelf life. Pressure treatment can be used for product modification through pressure gelatinization of starch and pressure denaturation of proteins. Key pressure–thermal treatment effects on vitamin, enzymes, flavor, co...

  3. Precision ozone vapor pressure measurements

    Science.gov (United States)

    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.

  4. Self pressuring HTP feed systems

    Energy Technology Data Exchange (ETDEWEB)

    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.

  5. Pressure sensor for sealed containers

    Science.gov (United States)

    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.

  6. Micro packaged MEMS pressure sensor for intracranial pressure measurement

    Science.gov (United States)

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

    2015-06-01

    This paper presents a micro packaged MEMS pressure sensor for intracranial pressure measurement which belongs to BioMEMS. It can be used in lumbar puncture surgery to measure intracranial pressure. Miniaturization is key for lumbar puncture surgery because the sensor must be small enough to allow it be placed in the reagent chamber of the lumbar puncture needle. The size of the sensor is decided by the size of the sensor chip and package. Our sensor chip is based on silicon piezoresistive effect and the size is 400 × 400 μm2. It is much smaller than the reported polymer intracranial pressure sensors such as liquid crystal polymer sensors. In terms of package, the traditional dual in-line package obviously could not match the size need, the minimal size of recently reported MEMS-based intracranial pressure sensors after packaging is 10 × 10 mm2. In this work, we are the first to introduce a quad flat no-lead package as the package form of piezoresistive intracranial pressure sensors, the whole size of the sensor is minimized to only 3 × 3 mm2. Considering the liquid measurement environment, the sensor is gummed and waterproof performance is tested; the sensitivity of the sensor is 0.9 × 10-2 mV/kPa. Project supported by the National Natural Science Foundation of China (Nos. 61025021, 61434001), and the ‘Thousands Talents’ Program for Pioneer Researchers and Its Innovation Team, China.

  7. Measurement of fast transient pressures

    International Nuclear Information System (INIS)

    The accuracy, reliability and sensitivity of a pressure transducers define its principal static characteristics. When the quantity measured varies with time, the measurement carries a dynamic error and a delay depending on the frequency of this variation. Hence, when fast pressure changes in a fluid have to be determined, different kinds of pressure transducers can be used depending on their inherent dynamic characteristics which must be compared with those of the transient phenomenon to be analysed. The text describes the pressure transducers generally employed in industry for analysing such phenomenon and gives two practical applications developed in the EDF: the first submits the measurements and results of pump cavitation tests carried out at the Vitry II EDF power station; the second deals with hammer blows particularly noticed in nuclear power stations and required the use of transducers of exceptionally high performance such as strain gauge transducers and piezoelectric transducers (response time within 1m sec.)

  8. Nutritional prediction of pressure ulcers.

    Science.gov (United States)

    Breslow, R A; Bergstrom, N

    1994-11-01

    This article focuses on nutritional risk factors that predict the development of pressure ulcers in hospital and nursing home patients. Cross-sectional studies associate inadequate energy and protein intake; underweight; low triceps skinfold measurement; and low serum albumin, low serum cholesterol, and low hemoglobin levels with pressure ulcers. Prospective studies identify inadequate energy and protein intake, a poor score on the Braden scale (a risk assessment instrument that includes a nutrition component), and possibly low serum albumin level as risk factors for developing a pressure ulcer. Nutritionists should provide a high-energy, high-protein diet for patients at risk of development of pressure ulcers to improve their dietary intake and nutritional status.

  9. Diagnosis of High Blood Pressure

    Medline Plus

    Full Text Available ... are consistently higher than 120/80 mmHg. Your child’s blood pressure numbers are outside average numbers for children of the same age, gender, and height . Once your health care provider ...

  10. Reducing catalytic converter pressure loss

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1996-06-01

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

  11. Diagnosis of High Blood Pressure

    Medline Plus

    Full Text Available ... Budget, Planning, & Legislative Advisory Committees Contact Us FAQs Home » Health Information for the Public » Health Topics » High ... also may ask you to check readings at home or at other locations that have blood pressure ...

  12. Intermolecular Interactions at high pressure

    DEFF Research Database (Denmark)

    Eikeland, Espen Zink

    2016-01-01

    . High-pressure crystallography is the perfect method for studying intermolecular interactions, by forcing the molecules closer together. In all three studied hydroquinone clathrates, new pressure induced phase transitions have been discovered using a mixture of pentane and isopentane as the pressure...... transformation is therefore most likely kinetically hindered when surrounded by solidified silicone oil. The calculated intermolecular energies in all three hydroquinone clathrates show the anticipated strong interactions in the host framework and the weaker host-guest interactions. As the pressure is raised...... illustrates how important it is to quantify all intermolecular interactions in structures. This enables researchers to see a more complete picture and not focus only on a few interactions deemed particularly important....

  13. [Pressure sores: management and treatment].

    Science.gov (United States)

    Goldschmidt, D; Seron, A; Jacquerye, A; Bustillo, A; Strale, H; Haubrechts, J; Del Marmol, V

    1997-09-01

    The global management of pressure sores is best ensured with a multidisciplinary approach. We present the experience of the "Groupe de Travail Escarres" (Pressure Sore Workgroup) which gathers physicians and nurses interested with this pathology. The majority of the decubitus ulcers will heal spontaneously with a conservative treatment only. This treatment typically aims at relieving the causes that lead to pressure sores, at eliminating the necrotic tissues, at obtaining favourable local conditions to allow wound healing and at controlling the health status of the patient. Surgical treatment of pressure sores is indicated when wound healing does not occur and when the health status of the patient is sufficiently good. Defect coverage is best carried out using myocutaneous flaps since their excellent blood supply allows a good cleansing of the wound. PMID:9411658

  14. Nonlinear opto-mechanical pressure

    CERN Document Server

    Conti, Claudio

    2014-01-01

    A transparent material exhibits ultra-fast 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, as optical manipulation, biophysics, cavity optomechanics, quantum optics, optical tractors, and is relevant in fundamental problems as the Abraham-Minkoswky dilemma, or the Casimir effect. Here we show that an ultra-fast 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.

  15. All-optical pressure sensor

    DEFF Research Database (Denmark)

    2014-01-01

    The present invention relates to an all-optical pressure sensor comprising a waveguide accommodating a distributed Bragg reflector. Pressure sensing can then be provided by utilizing effective index modulation of the waveguide and detection of a wavelength shift of light reflected from the Bragg...... reflector. Sound sensing may also be provided thereby having an all-optical microphone. One embodiment of the invention relates to an optical pressure sensor comprising at least one outer membrane and a waveguide, the waveguide comprising at least one core for confining and guiding light,at least one...... distributed Bragg reflector located in said at least one core, and at least one inner deflecting element forming at least a part of the core,wherein the pressure sensor is configured such that the geometry and/or dimension of the at least one core is changed when the at least one outer membrane is submitted...

  16. Diagnosis of High Blood Pressure

    Medline Plus

    Full Text Available ... Explore High Blood Pressure What Is... Other Names Causes Who Is at Risk Signs & Symptoms Diagnosis Treatments Prevention Living With Clinical Trials Links Related Topics Atherosclerosis DASH Eating Plan Overweight and Obesity Smoking and Your Heart ...

  17. Cryogenic MEMS Pressure Sensor Project

    Data.gov (United States)

    National Aeronautics and Space Administration — A directly immersible cryogenic MEMS pressure sensor will be developed. Each silicon die will contain a vacuum-reference and a tent-like membrane. Offsetting...

  18. Optical Fiber Tip Pressure Sensor

    OpenAIRE

    Wang, Xingwei

    2004-01-01

    Miniature pressure sensors which can endure harsh environments are a highly sought after goal in industrial, medical and research fields. Microelectromechanical systems (MEMS) are the current methods to fabricate such small sensors. However, they suffer from low sensitivity and poor mechanical properties. To fulfill the need for robust and reliable miniature pressure sensors that can operate under high temperatures, a novel type of optical fiber tip sensor only 125μm in diameter is ...

  19. High pressure rinsing parameters measurements

    Energy Technology Data Exchange (ETDEWEB)

    Cavaliere, E. [INFN Milano - LASA, Via F.lli Cervi 201, I-20090 Segrate (MI) (Italy); Fusetti, M. [INFN Milano - LASA, Via F.lli Cervi 201, I-20090 Segrate (MI) (Italy); Michelato, P. [INFN Milano - LASA, Via F.lli Cervi 201, I-20090 Segrate (MI) (Italy); Pagani, C. [INFN Milano - LASA, Via F.lli Cervi 201, I-20090 Segrate (MI) (Italy)]. E-mail: carlo.pagani@mi.infn.it; Pierini, P. [INFN Milano - LASA, Via F.lli Cervi 201, I-20090 Segrate (MI) (Italy); Paulon, R. [INFN Milano - LASA, Via F.lli Cervi 201, I-20090 Segrate (MI) (Italy); Sertore, D. [INFN Milano - LASA, Via F.lli Cervi 201, I-20090 Segrate (MI) (Italy)

    2006-07-15

    High pressure rinsing with ultra pure water jet is an essential step in the high field superconducting cavity production process. In this paper, we illustrate the experimental characterization of a HPR system, in terms of specific power and energy deposition on the cavity surfaces and on the damage threshold for niobium. These measurements are used to tentatively derive general rules for the optimization of the free process parameters (nozzle geometry, speeds and water pressure)

  20. Radiation-resistant pressure transducers

    International Nuclear Information System (INIS)

    Full text : The sensitive element of vibrofrequency tensor converter (VTC) is an electromechanical resonator of string type with electrostatic excitation of longitudinal mechanical vibrations. The string is made from tensosensitive thread-like monocrystal n-Ge1-x Six (length 1-5 mm, diameter 8-12 mcm) with current outlet and strictly fixed by ends at plate or deformable surface (in elastic element) at 50 mcm apartheid. With increasing Si atomic percent in n-Ge1-x Six the converter tens sensitivity increases. There has been shown the scheme of pressure transducer which contains monocrystalline silicon membrane and string tens converter from thread-like monocrystal Ge-Si. Using method, when crystal position on membrane while it deforms by pressure, corresponds to free (uptight) state, allowed to obtain the maximum sensitivity in measurement of pressure fluctuation. The transducers of absolute and pressure differential of this type can be used in automated systems of life activity. The high sensitivity of string transducers to pressure exceeding 100 hertz/mm (water column) permits to use them in devices for measuring gas concentration. The combination of optical and deformation methods of measurements forms the basis of their operation. The pressure change occurs due to the fact that gas molecules absorbing the quanta of incident light, become at excited state and then excitation energy of their vibrational-rotatory degrees of freedom converts to the energy of translational motion of molecules, i.e. to heat appropriate to pressure increase. Using these tens converters of high pressure one can prevent the possible accidents on oil pipe-like Baku-Tibilisi-Ceyhan

  1. High Pressure Treatment in Foods

    OpenAIRE

    Edwin Fabian Torres Bello; Gerardo González Martínez; Bernadette F. Klotz Ceberio; Dolores Rodrigo; Antonio Martínez López

    2014-01-01

    High hydrostatic pressure (HHP), a non-thermal technology, which typically uses water as a pressure transfer medium, is characterized by a minimal impact on food characteristics (sensory, nutritional, and functional). Today, this technology, present in many food companies, can effectively inactivate bacterial cells and many enzymes. All this makes HHP very attractive, with very good acceptance by consumers, who value the organoleptic characteristics of products processed by this non-thermal f...

  2. High Pressure Treatment in Foods

    OpenAIRE

    Torres Bello, Edwin Fabian; González Martínez, Gerardo; Bernadette F. Klotz Ceberio; Rodrigo Aliaga, Mª Dolores; Martínez López, Antonio

    2014-01-01

    Abstract: High hydrostatic pressure (HHP), a non-thermal technology, which typically uses water as a pressure transfer medium, is characterized by a minimal impact on food characteristics (sensory, nutritional, and functional). Today, this technology, present in many food companies, can effectively inactivate bacterial cells and many enzymes. All this makes HHP very attractive, with very good acceptance by consumers, who value the organoleptic characteristics of products processed by this non...

  3. Cavitation pressure in liquid helium

    OpenAIRE

    Caupin, Frederic; Balibar, Sebastien

    2001-01-01

    Recent experiments have suggested that, at low enough temperature, the homogeneous nucleation of bubbles occurs in liquid helium near the calculated spinodal limit. This was done in pure superfluid helium 4 and in pure normal liquid helium 3. However, in such experiments, where the negative pressure is produced by focusing an acoustic wave in the bulk liquid, the local amplitude of the instantaneous pressure or density is not directly measurable. In this article, we present a series of measur...

  4. Hydraulic calculation of pressure pipes

    OpenAIRE

    Mikhalev, M. A.

    2012-01-01

    In the present time there is only one classic method for hydraulic calculation of pressure pipes. In it fluid flow velocity and pipeline diameter are considered as given values.The paper proposes a procedure for physical modeling and hydraulic calculation of pressure pipes, based on the theory of similarity. Methods for obtaining similarity criteria from combinations of similarity numbers were discussed. Similarity numbers and criteria and criteria equations were defined.

  5. Crumpling under an ambient pressure

    OpenAIRE

    Lin, Y C; Wang, Y. L.; Liu, Y; Hong, T.M.

    2008-01-01

    A pressure chamber is designed to study the crumpling process under an ambient force. The compression force and its resulting radius for the ball obey a power law with an exponent that is independent of the thickness and initial size of the sheet. However, the exponent is found to be material-dependent and less than the universal value, 0.25, claimed by the previous simulations. The power law behavior disappears at high pressure when the compressibility drops discontinuously, which is suggest...

  6. High pressure effects on fruits and vegetables

    NARCIS (Netherlands)

    Timmermans, R.A.H.; Matser, A.M.

    2016-01-01

    The chapter provides an overview on different high pressure based treatments (high pressure pasteurization, blanching, pressure-assisted thermal processing, pressure-shift freezing and thawing) available for the preservation of fruits and vegetable products and extending their shelf life. Pressure t

  7. Pressure Ratio to Thermal Environments

    Science.gov (United States)

    Lopez, Pedro; Wang, Winston

    2012-01-01

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

  8. Pressure Tube and Pressure Vessel Reactors; certain comparisons

    International Nuclear Information System (INIS)

    In a comparison between pressure tube and pressure vessel type reactors for pressurized D2O coolant and natural uranium, one can say that reactors of these two types having the same net electrical output, overall thermal efficiency, reflected core volume and fuel lattice have roughly the same capital cost. In these circumstances, the fuel burn-up obtainable has a significant influence on the relative economics. Comparisons of burn-up values made on this basis are presented in this report and the influence on the results of certain design assumptions are discussed. One of the comparisons included is based on the dimensions and ratings proposed for CANDU. Moderator temperature coefficients are compared and differences in kinetic behaviour which generally result in different design philosophies for the two types are mentioned, A comparison of different methods of obtaining flux flattening is presented. The influence of slight enrichment and other coolants, (boiling D2O and gases) on the comparison between pressure tube and pressure vessel designs is discussed and illustrated with comparative designs for 400 MW electrical output. This paper was presented at the EAES Enlarged Symposium on Heterogeneous Heavy Water Power Reactors, Mallorca, October 10 - 14, 1960

  9. Questions and Answers about High Blood Pressure

    Science.gov (United States)

    ... Research Training & Career Development Grant programs for students, postdocs, and faculty Research at NIDDK Labs, faculty, and ... you have high blood pressure. How can I control or prevent high blood pressure? High blood pressure ...

  10. How Is High Blood Pressure Treated?

    Science.gov (United States)

    ... from the NHLBI on Twitter. How Is High Blood Pressure Treated? Based on your diagnosis, health care providers ... the medicine suspected of causing your high blood pressure. If high blood pressure persists or is first diagnosed as primary ...

  11. Avoid the Consequences of High Blood Pressure

    Science.gov (United States)

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

  12. 49 CFR 192.623 - Maximum and minimum allowable operating pressure; Low-pressure distribution systems.

    Science.gov (United States)

    2010-10-01

    ... distribution systems. (a) No person may operate a low-pressure distribution system at a pressure high enough to...) No person may operate a low pressure distribution system at a pressure lower than the...

  13. Conformable pressure vessel for high pressure gas storage

    Energy Technology Data Exchange (ETDEWEB)

    Simmons, Kevin L.; Johnson, Kenneth I.; Lavender, Curt A.; Newhouse, Norman L.; Yeggy, Brian C.

    2016-01-12

    A non-cylindrical pressure vessel storage tank is disclosed. The storage tank includes an internal structure. The internal structure is coupled to at least one wall of the storage tank. The internal structure shapes and internally supports the storage tank. The pressure vessel storage tank has a conformability of about 0.8 to about 1.0. The internal structure can be, but is not limited to, a Schwarz-P structure, an egg-crate shaped structure, or carbon fiber ligament structure.

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

    Science.gov (United States)

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

    1981-01-01

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

  15. High pressure neon arc lamp

    Science.gov (United States)

    Sze, Robert C.; Bigio, Irving J.

    2003-07-15

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

  16. Ruby fluorescence pressure scale: Revisited

    Institute of Scientific and Technical Information of China (English)

    Liu Lei; Bi Yan; Xu Ji-Ar

    2013-01-01

    Effect of non-hydrostatic stress on X-ray diffraction in a diamond anvil cell (DAC) is studied.The pressure gradient in the sample chamber leads to the broadening of the diffraction peaks,which increase with the hkl index of the crystal.It is found that the difference between the determined d-spacing compressive ratio d/d0 and the real d-spacing compressive ratio dr/d0 is determined by the yield stress of the pressure transmitting media (if used) and the shear modulus of the sample.On the basis of the corrected experiment data of Mao et al.(MXB86),which was used to calibrate the most widely used ruby fluorescence scale,a new relationship of ruby fluorescence pressure scale is corrected,i.e.,P =(1904/9.827)[(1 +△λ/λ0)9.827-1}.

  17. Vegetarian diet and blood pressure.

    Science.gov (United States)

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

    1987-01-01

    There is now convincing evidence from epidemiological studies and randomized controlled trials that adoption of an ovo-lacto vegetarian diet leads to blood pressure reduction in both normotensive and hypertensive subjects. This effect appears to be independent of both dietary sodium and weight loss but additive to effects of weight reduction. Long-term adherence to a vegetarian diet is associated with less of a rise of blood pressure with age and a decreased prevalence of hypertension. The nutrients responsible for these effects have not been clearly identified and the mechanisms involved are unknown. Resolution of these questions is needed to enable more widespread adoption of dietary changes which may reduce the prevalence of hypertension, reduce antihypertensive drug dependence and by effects on blood pressure and blood lipids ameliorate the natural history of hypertensive cardiovascular disease.

  18. Interarm difference in blood pressure

    DEFF Research Database (Denmark)

    Mehlsen, Jesper; Wiinberg, Niels

    2014-01-01

    without known cardiac disease, renal disease, or diabetes mellitus. 824 patients (453 women) with mean age of 72 years (range: 50-101) were included. 491 patients had a diagnosis of hypertension and peripheral arterial disease (PAD) was present in 386 patients. Systolic blood pressure was 143 ± 24 mm......Hg and 142 ± 24 mmHg on the right and left arm, respectively (P = 0.015). The interarm difference was greater in patients with hypertension (P = 0.002) and PAD (P blood pressure was reproducible...... for differences >20 mmHg. This study confirmed the presence of a systematic but clinically insignificant difference in systolic blood pressure between arms. The interarm difference was larger in hypertension and PAD. Consistent lateralisation is present for differences ≥20 mmHg and an interarm difference >25 mm...

  19. Melting of Ice under Pressure

    Energy Technology Data Exchange (ETDEWEB)

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

    2008-07-31

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

  20. IIH with normal CSF pressures?

    Directory of Open Access Journals (Sweden)

    Soh Youn Suh

    2013-01-01

    Full Text Available Idiopathic intracranial hypertension (IIH is a condition of raised intracranial pressure (ICP in the absence of space occupying lesions. ICP is usually measured by lumbar puncture and a cerebrospinal fluid (CSF pressure above 250 mm H 2 O is one of the diagnostic criteria of IIH. Recently, we have encountered two patients who complained of headaches and exhibited disc swelling without an increased ICP. We prescribed acetazolamide and followed both patients frequently; because of the definite disc swelling with IIH related symptoms. Symptoms and signs resolved in both patients after they started taking acetazolamide. It is generally known that an elevated ICP, as measured by lumbar puncture, is the most important diagnostic sign of IIH. However, these cases caution even when CSF pressure is within the normal range, that suspicion should be raised when a patient has papilledema with related symptoms, since untreated papilledema may cause progressive and irreversible visual loss.

  1. Pressure moderation and effective pressure in Navier-Stokes flows

    Science.gov (United States)

    Tran, Chuong V.; Yu, Xinwei

    2016-10-01

    We study the Cauchy problem of the Navier-Stokes equations by both semi-analytic and classical energy methods. The former approach provides a physical picture of how viscous effects may or may not be able to suppress singularity development. In the latter approach, we examine the pressure term that drives the dynamics of the velocity norms \\parallel u{{\\parallel}{{Lq}}} , for q≥slant 3 . A key idea behind this investigation is due to the fact that the pressure p in this term is determined up to a function of both space and |u| , say P(x,|u|) , which may assume relatively broad forms. This allows us to use P as a pressure moderator in the evolution equation for \\parallel u{{\\parallel}{{Lq}}} , whereby optimal regularity criteria can be sought by varying P within its admissible classes. New regularity criteria are derived with and without making use of the moderator. The results obtained in the absence of the moderator feature some improvement over existing criteria in the literature. Several criteria are derived in terms of the moderated (effective) pressure p+P . A simple moderation scheme and the plausibility of the present approach to the problem of Navier-Stokes regularity are discussed.

  2. Internal pressure and solubility parameter as a function of pressure

    DEFF Research Database (Denmark)

    Verdier, Sylvain Charles Roland; Andersen, Simon Ivar

    2005-01-01

    maximum contrary to solubility parameter. An indirect method was chosen to estimate internal pressure, using thermal expansivities (determined by microcalorimetry) and isothermal compressibilities (determined by density measurements). The uncertainty is within 2% for the expansivity and 0.1% for the...

  3. High Pressure Treatment in Foods

    Directory of Open Access Journals (Sweden)

    Edwin Fabian Torres Bello

    2014-08-01

    Full Text Available High hydrostatic pressure (HHP, a non-thermal technology, which typically uses water as a pressure transfer medium, is characterized by a minimal impact on food characteristics (sensory, nutritional, and functional. Today, this technology, present in many food companies, can effectively inactivate bacterial cells and many enzymes. All this makes HHP very attractive, with very good acceptance by consumers, who value the organoleptic characteristics of products processed by this non-thermal food preservation technology because they associate these products with fresh-like. On the other hand, this technology reduces the need for non-natural synthetic additives of low consumer acceptance.

  4. Blood pressure modifies retinal susceptibility to intraocular pressure elevation.

    Directory of Open Access Journals (Sweden)

    Zheng He

    Full Text Available Primary open angle glaucoma affects more than 67 million people. Elevated intraocular pressure (IOP is a risk factor for glaucoma and may reduce nutrient availability by decreasing ocular perfusion pressure (OPP. An interaction between arterial blood pressure and IOP determines OPP; but the exact contribution that these factors have for retinal function is not fully understood. Here we sought to determine how acute modifications of arterial pressure will affect the susceptibility of neuronal function and blood flow to IOP challenge. Anaesthetized (ketamine:xylazine Long-Evan rats with low (∼60 mmHg, sodium nitroprusside infusion, moderate (∼100 mmHg, saline, or high levels (∼160 mmHg, angiotensin II of mean arterial pressure (MAP, n = 5-10 per group were subjected to IOP challenge (10-120 mmHg, 5 mmHg steps every 3 minutes. Electroretinograms were measured at each IOP step to assess bipolar cell (b-wave and inner retinal function (scotopic threshold response or STR. Ocular blood flow was measured using laser-Doppler flowmetry in groups with similar MAP level and the same IOP challenge protocol. Both b-wave and STR amplitudes decreased with IOP elevation. Retinal function was less susceptible to IOP challenge when MAP was high, whereas the converse was true for low MAP. Consistent with the effects on retinal function, higher IOP was needed to attenuated ocular blood flow in animals with higher MAP. The susceptibility of retinal function to IOP challenge can be ameliorated by acute high BP, and exacerbated by low BP. This is partially mediated by modifications in ocular blood flow.

  5. Numerical simulation research on improving cleaning cuttings effectiveness with pulsed jet under conifning pressure%围压条件下脉冲射流提高清岩效果数值模拟研究

    Institute of Scientific and Technical Information of China (English)

    刘爽; 李根生; 史怀忠

    2015-01-01

    The drilling technology with pulsed jet is highly capable of cleaning the cuttings, but its acceleration mechanism remains unknown. By establishing a physical model for bottom hole cleaning cuttings by pulsed jet with single-nozzle under conifning pressure, the numerical simulation research was conducted on the whole process of cleaning cuttings by pulsed jet, and the main factors affecting the cleaning cuttings effect by pulsed jet was analyzed. The research ifnding shows that unsteady state rotational lfow is one of the main reasons for improvement of cleaning cuttings effect by pulsed jet. Under the same lfow rate, the cleaning cuttings efifciency by pulsed jet is about 1-1.6 times that of continuous jet in average. The efifciency of cleaning cuttings by pulsed jet increases with the increase of nozzle diameter and inlet lfowrate. The conifning pressure has small effect on the process of cleaning cuttings by pulsed jet. The overall effect of cleaning cuttings by low frequency pulsed jet is good, with the increase of particle sizes, the heterogeneity of cuttings distribution within the impact area at hole bottom is intensiifed and the efifciency of cleaning cuttings by pulsed jet is reduced. The resulting conclusions provide a theoretical guidance for research on acceleration technique by pulsed jet.%脉冲射流钻井技术具有高效清岩能力,但其提速机制还不十分清楚。通过建立围压条件下单喷嘴脉冲射流井底清岩物理模型,对脉冲射流清岩过程进行了数值模拟研究,分析了影响脉冲射流清岩效果的主要因素。结果表明,非稳态旋流是脉冲射流提高清岩效果的主要原因之一,在相同排量条件下,脉冲射流清岩效率比连续射流平均提高约1~1.6倍。脉冲射流清岩效率随着喷嘴直径和入口流速的增大而增大;围压对脉冲射流清岩过程影响较小;低频率脉冲射流的清岩总体效果较好;随着岩屑粒径增大,井底冲击

  6. Research on pressure control of pressurizer in pressurized water reactor nuclear power plant

    Science.gov (United States)

    Dai, Ling; Yang, Xuhong; Liu, Gang; Ye, Jianhua; Qian, Hong; Xue, Yang

    2010-07-01

    Pressurizer is one of the most important components in the nuclear reactor system. Its function is to keep the pressure of the primary circuit. It can prevent shutdown of the system from the reactor accident under the normal transient state while keeping the setting value in the normal run-time. This paper is mainly research on the pressure system which is running in the Daya Bay Nuclear Power Plant. A conventional PID controller and a fuzzy controller are designed through analyzing the dynamic characteristics and calculating the transfer function. Then a fuzzy PID controller is designed by analyzing the results of two controllers. The fuzzy PID controller achieves the optimal control system finally.

  7. LLL dynamic high pressure experiments

    Energy Technology Data Exchange (ETDEWEB)

    Nellis, W.J.

    1979-01-01

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

  8. Vital Signs - High Blood Pressure

    Centers for Disease Control (CDC) Podcasts

    2012-10-02

    In the U.S., nearly one third of the adult population have high blood pressure, the leading risk factor for heart disease and stroke - two of the nation's leading causes of death.  Created: 10/2/2012 by National Center for Chronic Disease Prevention and Health Promotion (NCCDPHP).   Date Released: 10/17/2012.

  9. Pressure vessel having continuous sidewall

    Science.gov (United States)

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

    2011-01-01

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

  10. Diagnosis of High Blood Pressure

    Medline Plus

    Full Text Available ... Health Topics Education & Awareness Resources Contact The Health Information Center Health Professionals Systematic Evidence Reviews & Clinical Practice ... Legislative Advisory Committees Contact Us FAQs Home » Health Information for the Public » Health Topics » High Blood Pressure » ...

  11. Water Pressure. Water in Africa.

    Science.gov (United States)

    Garrett, Carly Sporer

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

  12. Bioinspired pressure actuated adhesive system

    NARCIS (Netherlands)

    Paretkar, D.R.; Kamperman, M.M.G.; Schneider, A.S.; Martina, D.; Creton, C.; Arzt, E.

    2011-01-01

    We developed a dry synthetic adhesive system inspired by gecko feet adhesion that can switch reversibly from adhesion to non-adhesion with applied pressure as external stimulus. Micropatterned polydimethylsiloxane (PDMS) surfaces with pillars of 30 µm length and 10 µm diameter were fabricated using

  13. Three Beam Interfering Pressure Gauge①

    Institute of Scientific and Technical Information of China (English)

    WUZhaoxia; TANGXuhui; 等

    1997-01-01

    In order to solve the problem of high precision,complete electric insulating detection of the pressure measuring system,we have developed the three-beam interferometer.In this paper,the operation principle,structure of the system and measuring results are given.

  14. Graphene based piezoresistive pressure sensor

    NARCIS (Netherlands)

    Zhu, S.E.; Ghatkesar, M.K.; Zhang, C.; Janssen, G.C.A.M.

    2013-01-01

    We present a pressure sensor based on the piezoresistive effect of graphene. The sensor is a 100 nm thick, 280 μm wide square silicon nitride membrane with graphene meander patterns located on the maximum strain area. The multilayer, polycrystalline graphene was obtained by chemical vapor deposition

  15. The Vapour Pressure of Plutonium

    International Nuclear Information System (INIS)

    The vapour pressure of liquid plutonium has been determined over the temperature range 1100 to 1800°K by the Knudsen effusion method. The least-squares equation which fits the data is log10p(atm) = -17 420/T(°K) + 4.913. The standard deviation corresponds to about ±10% in the pressures calculated from this equation. The heat of vaporization computed from the temperature dependence of the experimental data is ΔH0298 = 82.3 kcal/g-at. The heat computed by combining independent entropy and heat capacity data with the present measurements is ΔH0298 = 82.1 kcal/g-at. Effects of oxygen upon the volatility of liquid plutonium were sought by comparing the vapour pressures observed with the liquid in contact with tantalum, tantalum carbide, magnesia, and plutonium sesquioxide. No differences were found. In addition, the vapour pressure was measured with different degrees of vacuum in the system. No effect was found here either, except that in very poor vacuums a surface film of oxide apparently formed and reduced the volatility by about a factor of 2. (author)

  16. Pressure gauge experiments in India

    Digital Repository Service at National Institute of Oceanography (India)

    Joseph, A.; Desa, E.; VijayKumar, K.; Desa, E.S.; Desai, R.G.P.; Prabhudesai, S.

    Pressure measurements made in differing turbid water bodies and turbulent clear-water bodies have led to the inference that the effective mean-depth in situ density value, Row eff, of these water bodies is less than the corresponding bulk density...

  17. Diagnosis of High Blood Pressure

    Medline Plus

    Full Text Available ... Entire Site Health Topics News & Resources Intramural Research Public Health Topics Education & Awareness Resources Contact The Health Information ... Contact Us FAQs Home » Health Information for the Public » Health Topics » High Blood Pressure » Diagnosis of High Blood ...

  18. The Power of Peer Pressure

    Science.gov (United States)

    Wingle, Jane

    2006-01-01

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

  19. Diagnosis of High Blood Pressure

    Medline Plus

    Full Text Available ... Related Topics Atherosclerosis DASH Eating Plan Overweight and Obesity Smoking and Your Heart Stroke Send a link ... are consistently higher than 120/80 mmHg. Your child’s blood pressure numbers are outside average numbers for ...

  20. Cavity Pressure Behaviour in Micro Injection Moulding

    DEFF Research Database (Denmark)

    Griffiths, C.A.; Dimov, S.S.; Scholz, S.;

    2010-01-01

    as well as with the filling of the cavity by the polymer melt. In this paper, two parameters derived from cavity pressure over time (i.e. pressure work). The influence of four µIM parameters (melt temperature, mould temperature, injection speed, aand packing pressure) on the two pressure...

  1. A piezo-bar pressure probe

    Science.gov (United States)

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

    1967-01-01

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

  2. Vapor Pressure Measurements in a Closed System

    Science.gov (United States)

    Iannone, Mark

    2006-01-01

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

  3. Distortion Of Pressure Signals In Pneumatic Tubes

    Science.gov (United States)

    Whitmore, Stephen A.; Gilyard, Glenn B.; Curry, Robert; Lindsey, William

    1993-01-01

    NASA technical memorandum describes experimental investigation of distorting effects of propagation of pressure signals along narrow pneumatic tubes from pressure-sensing orifices on surfaces of models or aircraft to pressure sensors distant from orifices. Pressure signals distorted principally by frictional damping along walls of tubes and by reflections at orifice and sensor ends.

  4. 46 CFR 119.330 - Pressure vessels.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 4 2010-10-01 2010-10-01 false Pressure vessels. 119.330 Section 119.330 Shipping COAST... Machinery § 119.330 Pressure vessels. All unfired pressure vessels must be installed to the satisfaction of the cognizant OCMI. The design, construction, and original testing of such unfired pressure...

  5. 46 CFR 169.249 - Pressure vessels.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 7 2010-10-01 2010-10-01 false Pressure vessels. 169.249 Section 169.249 Shipping COAST... and Certification Inspections § 169.249 Pressure vessels. Pressure vessels must meet the requirements of part 54 of this chapter. The inspection procedures for pressure vessels are contained in...

  6. 46 CFR 182.330 - Pressure vessels.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 7 2010-10-01 2010-10-01 false Pressure vessels. 182.330 Section 182.330 Shipping COAST...) MACHINERY INSTALLATION Auxiliary Machinery § 182.330 Pressure vessels. All unfired pressure vessels must be... unfired pressure vessels must meet the applicable requirements of subchapter F (Marine Engineering)...

  7. Determination of Secondary Encasement Pipe Design Pressure

    International Nuclear Information System (INIS)

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

  8. Nonequilibrium thermodynamics of pressure solution

    Science.gov (United States)

    Lehner, F. K.; Bataille, J.

    1984-01-01

    This paper is concerned with the thermodynamic theory of solution and precipitation processes in wet crustal rocks and with the mechanism of steady pressure-solution slip in ‘contact zones,’ such as grain-to-grain contacts, fracture surfaces, and permeable gouge layers, that are infiltrated by a mobile aqueous solution phase. A local dissipation jump condition at the phase boundary is fundamental to identifying the thermodynamic force driving the solution and precipitation process and is used here in setting up linear phenomenological relations to model near-equilibrium phase transformation kinetics. The local thermodynamic equilibrium of a stressed pure solid in contact with its melt or solution phase is governed by Gibbs's relation, which is rederived here, in a manner emphasizing its independence of constitutive assumptions for the solid while neglecting surface tension and diffusion in the solid. Fluid-infiltrated contact zones, such as those formed by rough surfaces, cannot generally be in thermodynamic equilibrium, especially during an ongoing process of pressure-solution slip, and the existing equilibrium formulations are incorrect in overlooking dissipative processes tending to eliminate fluctuations in superficial free energies due to stress concentrations near asperities, defects, or impurities. Steady pressure-solution slip is likely to exhibit a nonlinear dependence of slip rate on shear stress and effective normal stress, due to a dependence of the contact-zone state on the latter. Given that this dependence is negligible within some range, linear relations for pressure-solution slip can be derived for the limiting cases of diffusion-controlled and interface-reaction-controlled rates. A criterion for rate control by one of these mechanisms is set by the magnitude of the dimensionless quantity kδ/2C pD, where k is the interfacial transfer coefficient, δ is the mean diffusion path length, C p is the solubility at pressure p, and D is the mass

  9. Orion Suit Loop Variable Pressure Regulator Development

    Science.gov (United States)

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

    2014-01-01

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

  10. Effect of overbalance pressure on formation damage

    Energy Technology Data Exchange (ETDEWEB)

    Jilani, S.Z.; Menouar, H.; Al-Majed, A.A. [Center for Petroleum and Minerals, The Research Institute, King Fahd University of Petroleum and Minerals, Mail Box 2002, 31261 Dhahran (Saudi Arabia); Khan, M.A. [Center for Applied Physical Sciences, The Research Institute, King Fahd University of Petroleum and Minerals, 31261 Dhahran (Saudi Arabia)

    2002-10-01

    Experiments were conducted to investigate the influence of overbalance pressure on formation damage during drilling operations. An innovative ultrasonic method was employed to measure mud invasion depth. It was observed that mud invasion depth decreases with increasing overbalance pressure until it reaches a critical pressure. Beyond that, invasion depth increases with overbalance pressure. The above phenomenon reflects a strong physical relationship between overbalance pressure and mud fines and filtrate invasion depth.

  11. Research on Normal Human Plantar Pressure Test

    Directory of Open Access Journals (Sweden)

    Liu Xi Yang

    2016-01-01

    Full Text Available FSR400 pressure sensor, nRF905 wireless transceiver and MSP40 SCM are used to design the insole pressure collection system, LabVIEW is used to make HMI of data acquisition, collecting a certain amount of normal human foot pressure data, statistical analysis of pressure distribution relations about five stages of swing phase during walking, using the grid closeness degree to identify plantar pressure distribution pattern recognition, and the algorithm simulation, experimental results demonstrated this method feasible.

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

    Science.gov (United States)

    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.

  13. Relating external compressing pressure to mean arterial pressure in non-invasive blood pressure measurements.

    Science.gov (United States)

    Chin, K Y; Panerai, R B

    2015-01-01

    Arterial volume clamping uses external compression of an artery to provide continuous non-invasive measurement of arterial blood pressure. It has been assumed that mean arterial pressure (MAP) corresponds to the point where unloading leads to the maximum oscillation of the arterial wall as reflected by photoplethysmogram (PPG), an assumption that has been challenged. Five subjects were recruited for the study (three males, mean age (SD) = 32 (15) years). The PPG waveform was analysed to identify the relationship between the external compressing pressure, PPG pulse amplitude and MAP. Two separate tests were carried out at compression step intervals of 10 mmHg and 2 mmHg, respectively. No significant differences were found between the two tests. The bias between the compressing pressure and the MAP was -4.7 ± 5.63 mmHg (p < 0.001) showing a normal distribution. Further research is needed to identify optimal algorithms for estimation of MAP using PPG associated with arterial compression. PMID:25429784

  14. High pressure processing of meat

    DEFF Research Database (Denmark)

    Grossi, Alberto; Christensen, Mette; Ertbjerg, Per;

    Abstract Background: The research of high pressure (HP) processing of meat based foods needs to address how pressure affects protein interactions, aggregation and/or gelation. The understanding of the gel forming properties of myofibrillar components is fundamental for the development of muscle......–PAGE gels of myofibrillar protein extract from HP treated meat showed that myofibrillar proteins form high molecular weight aggregates after HP treatment. Myofibrillar protein aggregates were stable in a reducing environment, suggesting that disulfide bonds are not the main molecular interactions...... the rheological properties of pork meat batters by inducing formation of protein gels. HP induced protein gels are suggested to be formed by high molecular weight myofibrillar protein aggregates and by peptides formed by lysosomal enzyme-induced cleavage of myofibrillar proteins. Perspectives: The data presented...

  15. Closed incision negative pressure therapy

    DEFF Research Database (Denmark)

    Willy, Christian; Agarwal, Animesh; Andersen, Charles A;

    2016-01-01

    Surgical site occurrences (SSOs) affect up to or over 25% of patients undergoing operative procedures, with the subset of surgical site infections (SSIs) being the most common. Commercially available closed incision negative pressure therapy (ciNPT) may offer surgeons an additional option to manage...... of Controlled Trials using key words 'prevention', 'negative pressure wound therapy (NPWT)', 'active incisional management', 'incisional vacuum therapy', 'incisional NPWT', 'incisional wound VAC', 'closed incisional NPWT', 'wound infection', and 'SSIs' identified peer-reviewed studies published from 2000....... A majority presented data supporting ciNPT use. Numerous publications reported SSI risk factors, with the most common including obesity (body mass index ≥30 kg/m(2) ); diabetes mellitus; tobacco use; or prolonged surgical time. We recommend that the surgeon assess the individual patient's risk factors...

  16. Incisional Negative Pressure Wound Therapy

    DEFF Research Database (Denmark)

    Hyldig, Nana; Birke-Sorensen, Hanne; Kruse, Marie;

    formation (52%) compared to standard care. The reduction in wound dehiscence was not statistically significant. The numbers needed to treat were 3 (seroma), 17 (dehiscence), and 25 (infection). Methodical heterogeneity across studies led to downgrading quality of evidence to moderate for infection......Aim: Postoperative wound complications make many surgical procedures unnecessarily complex, particularly in high-risk patients. Negative Pressure Wound Therapy is well recognized in the management of open wounds. In recent years, it has been introduced as well in the management of closed surgical...... incisions to reduce postoperative wound complications, though the evidence base to support this intervention is limited. The aim of this study was to assess if Negative Pressure Wound Therapy (NPWT) reduces postoperative complications when applied on closed surgical incisions. Method: A systematic review...

  17. Pressurized-thermal-shock technology

    International Nuclear Information System (INIS)

    It was recognized at the time the original Issues on Pressurized Thermal Shock (IPTS) studies were conducted that distinct vertical plumes of cooling water form beneath the cold leg inlet nozzles during those particular transients that exhibit fluid/thermal stratification. The formation of these plumes (referred to as thermal streaming) induces a time-dependent circumferential temperature variation on the inner surface of the Reactor Pressure Vessel (RPV) wall that creates an axial stress component. This axial stress component is in addition to the axial stress components induced by time-dependent radial temperature variation through the wall thickness and the time-dependent pressure transient. This additional axial stress component will result in a larger axial stress resultant that results in a larger stress-intensity factor acting on circumferential flaws, thus reducing the fracture margin for circumferential flaws. Although this was recognized at the time of the original IPTS study, the contribution appeared to be relatively small; therefore, it was neglected. The original IPTS studies were performed with OCA-P, a computer program developed at ORNL to analyze the cleavage fracture response of a nuclear RPV subjected to PTS loading. OCA-P is a one-dimensional (1-D) finite-element code that analyzes the stresses and stress-intensity factors (axial and tangential) resulting from the pressure and the radial temperature variation through the wall thickness only. The HSST Program is investigating the potential effects of thermal-streaming-induced stresses in circumferential welds on the reactor vessel PTS analyses. The initial phase of this investigation focused on an evaluation of the available thermal-hydraulic data and analyses results. The objective for the initial phase of the investigation is to evaluate thermal-streaming behavior under conditions relevant to the operation of U.S. PWRs and chracterize any predicted thermal-streaming plumes

  18. The calculation of pressure vessels

    International Nuclear Information System (INIS)

    The calculation guidelines of the Arbeitsgemeinschaft Druckbehaelter (task group for pressure vessels) have been revised with the following objective: conversion to international standards (SI), adaption to the latest state of guidelines for production and testing, revision of the contents of individual regulations. Another target of the cooperating interest groups of producers, operators, and supervisory bodies was a harmonization of the approaches for calculation with other German guidelines, in particular the Technische Regeln fuer Dampfkessel (technical regulations for steam boilers). (orig./RW)

  19. TBM pressure models: calculation tools

    OpenAIRE

    Gerheim Souza Dias, Tiago; Bezuijen, Adam

    2015-01-01

    Mechanized tunnel construction in soft ground has evolved significantly over the last 20 years, especially on the matter of settlement control. This was achieved by guiding the TBM operation to control the main factors that induce soil displacements, namely the face pressure and the closure of the soil-lining void. Nowadays, TBMs can be operated within strict serviceability requirements. However, several mechanisms of the excavation cycle are still not taken into account when estimating the i...

  20. High pressure Hugoniot of sapphire

    Energy Technology Data Exchange (ETDEWEB)

    Erskine, D.

    1993-07-01

    The Hugoniot of sapphire was measured from 80 GPa to 340 GPa in shock-wave experiments using projectiles accelerated by a two stage gas gun. Transit times of the shock waves were measured either optically with a streak camera or through electrical pin contacts. The Hugoniot in this pressure range fits U{sub s}=8.74+0.96 U{sub p}in km/s.

  1. Pressure losses in pneumatic transport

    OpenAIRE

    Ottjes, J.A.

    1982-01-01

    A model is derived to calculate the pressure losses originating from the dilute phase pneumatic transport of coarse particles in the horizontal stationary flow regime. The model is based on the balance of drag forces and frictional forces acting on the particles during pneumatic transport. The particles are characterized by the particle terminal velocity, the particle âwall sliding friction coefficient and the coefficient of restitution between particles and wall. The influence of the inhomog...

  2. High pressure rinsing system comparison

    Energy Technology Data Exchange (ETDEWEB)

    D. Sertore; M. Fusetti; P. Michelato; Carlo Pagani; Toshiyasu Higo; Jin-Seok Hong; K. Saito; G. Ciovati; T. Rothgeb

    2007-06-01

    High pressure rinsing (HPR) is a key process for the surface preparation of high field superconducting cavities. A portable apparatus for the water jet characterization, based on the transferred momentum between the water jet and a load cell, has been used in different laboratories. This apparatus allows to collected quantitative parameters that characterize the HPR water jet. In this paper, we present a quantitative comparison of the different water jet produced by various nozzles routinely used in different laboratories for the HPR process

  3. Crime, Education and Peer Pressure

    OpenAIRE

    P. Buonanno

    2003-01-01

    We present a dynamic two-period model of individual behaviour with heterogeneous agents in which individuals decide how to allocate their disposable time between education, crime and work in the legal sector. Education has a multiple role: it implies higher expected wages in the legal sector, increasing the opportunity cost of committing crime and it has a sort of “civilization” effect that makes more costly to engage in criminal activities. We model this effect by introducing a peer pressure...

  4. Pressure induced ageing of polymers

    Science.gov (United States)

    Emri, I.; Knauss, W. G.

    1988-01-01

    The nonlinearly viscoelastic response of an amorphous homopolymer is considered under aspects of time dependent free volume behavior. In contrast to linearly viscoelastic solids, this model couples shear and volume deformation through a shift function which influences the rate of molecular relaxation or creep. Sample computations produce all those qualitative features one observes normally in uniaxial tension including the rate dependent formation of a yield point as a consequence of the history of an imposed pressure.

  5. Pressurized water reactor inspection procedures

    International Nuclear Information System (INIS)

    Inspections of the reactor pressure vessels of pressurized water reactors (PWR) so far used to be carried out with different central mast manipulators. For technical reasons, parallel inspections of two manipulators alongside work on the refueling cavity, so as to reduce the time spent on the critical path in a revision outage, are not possible. Efforts made to minimize the inspection time required with one manipulator have been successful, but their effects are limited. Major reductions in inspection time can be achieved only if inspections are run with two manipulators in parallel. The decentralized manipulator built by GEC Alsthom Energie and so far emmployed in boiling water reactors in the USA, Spain, Switzerland and Japan allows two systems to be used in parallel, thus reducing the time required for standard inspection of a pressure vessel from some six days to three days. These savings of approximately three days are made possible without any compromises in terms of positioning by rail-bound systems. During inspection, the reactor refueling cavity is available for other revision work without any restrictions. The manipulator can be used equally well for inspecting standard PWR, PWR with a thermal shield, for inspecting the land between in-core instrumentation nozzles, BWR with and without jet pumps (complementary inspection), and for inspecting core support shrouds. (orig.)

  6. Automated postoperative blood pressure control

    Institute of Scientific and Technical Information of China (English)

    Hang ZHENG; Kuanyi ZHU

    2005-01-01

    It is very important to maintain the level of mean arterial pressure (MAP).The MAP control is applied in many clinical situations,including limiting bleeding during cardiac surgery and promoting healing for patient's post-surgery.This paper presents a fuzzy controller-based multiple-model adaptive control system for postoperative blood pressure management.Multiple-model adaptive control (MMAC) algorithm is used to identify the patient model,and it is a feasible system identification method even in the presence of large noise.Fuzzy control (FC) method is used to design controller bank.Each fuzzy controller in the controller bank is in fact a nonlinear proportional-integral (PI) controller,whose proportional gain and integral gain are adjusted continuously according to error and rate of change of error of the plant output,resulting in better dynamic and stable control performance than the regular PI controller,especially when a nonlinear process is involved.For demonstration,a nonlinear,pulsatile-flow patient model is used for simulation,and the results show that the adaptive control system can effectively handle the changes in patient's dynamics and provide satisfactory performance in regulation of blood pressure of hypertension patients.

  7. ITER Port Interspace Pressure Calculations

    Energy Technology Data Exchange (ETDEWEB)

    Carbajo, Juan J [ORNL; Van Hove, Walter A [ORNL

    2016-01-01

    The ITER Vacuum Vessel (VV) is equipped with 54 access ports. Each of these ports has an opening in the bioshield that communicates with a dedicated port cell. During Tokamak operation, the bioshield opening must be closed with a concrete plug to shield the radiation coming from the plasma. This port plug separates the port cell into a Port Interspace (between VV closure lid and Port Plug) on the inner side and the Port Cell on the outer side. This paper presents calculations of pressures and temperatures in the ITER (Ref. 1) Port Interspace after a double-ended guillotine break (DEGB) of a pipe of the Tokamak Cooling Water System (TCWS) with high temperature water. It is assumed that this DEGB occurs during the worst possible conditions, which are during water baking operation, with water at a temperature of 523 K (250 C) and at a pressure of 4.4 MPa. These conditions are more severe than during normal Tokamak operation, with the water at 398 K (125 C) and 2 MPa. Two computer codes are employed in these calculations: RELAP5-3D Version 4.2.1 (Ref. 2) to calculate the blowdown releases from the pipe break, and MELCOR, Version 1.8.6 (Ref. 3) to calculate the pressures and temperatures in the Port Interspace. A sensitivity study has been performed to optimize some flow areas.

  8. Ultrahigh Temperature Capacitive Pressure Sensor

    Science.gov (United States)

    Harsh, Kevin

    2014-01-01

    Robust, miniaturized sensing systems are needed to improve performance, increase efficiency, and track system health status and failure modes of advanced propulsion systems. Because microsensors must operate in extremely harsh environments, there are many technical challenges involved in developing reliable systems. In addition to high temperatures and pressures, sensing systems are exposed to oxidation, corrosion, thermal shock, fatigue, fouling, and abrasive wear. In these harsh conditions, sensors must be able to withstand high flow rates, vibration, jet fuel, and exhaust. In order for existing and future aeropropulsion turbine engines to improve safety and reduce cost and emissions while controlling engine instabilities, more accurate and complete sensor information is necessary. High-temperature (300 to 1,350 C) capacitive pressure sensors are of particular interest due to their high measurement bandwidth and inherent suitability for wireless readout schemes. The objective of this project is to develop a capacitive pressure sensor based on silicon carbon nitride (SiCN), a new class of high-temperature ceramic materials, which possesses excellent mechanical and electric properties at temperatures up to 1,600 C.

  9. Advanced low pressure steam turbines

    Energy Technology Data Exchange (ETDEWEB)

    Weiss, A.P.

    1998-07-01

    Low pressure steam turbines for fossil and nuclear power plants are designed to provide maximum exhaust area per flow in order to achieve high efficiency and at the same time reduce the number of flows and thereby minimize costs. Therefore they are characterized by very long last stage blades (LSB) mounted on a relatively small hub diameter compared to other axial turbines e.g. gas turbines. The paper summarizes how this very high length to diameter ratio of the LSB creates challenging flow conditions concerning stage and blading design. The turbine designer has to cope with very low hub reaction and the corresponding danger of flow separation. Due to the extreme change of circumferential velocity from hub to tip and flow pitch angles in the range of 45 or more the flow field is highly three-dimensional even without considering endwall flow phenomena. The LSB is subjected to high inlet Mach number at the hub as well as at the tip. Furthermore, the exit Mach number at the tip might reach twice the speed of sound. This leads to strong compression shocks with high shock losses. Many ways to master these challenges have been described in the literature. A summary of these design features is given in the paper. A common goal of all design measures is to reduce the significant radial pressure gradient at the exit of the last stage vane. Beside the well-known forced ``vortex design'', the effects of blade lean angle and sweep angle are explained. Both features generate an additional radial force on the flow which at least partly balances the radial pressure gradient due to swirl. Finally, the major objective of the paper is to present how all these design features have been applied in combination for an actual advanced large low pressure steam turbine design. A highly three-dimensional last stage vane is introduced. It can be shown that it is possible to optimize radial mass flow distribution and pressure distribution simultaneously.

  10. Segmental blood pressure after total hip replacement

    DEFF Research Database (Denmark)

    Gebuhr, Peter Henrik; Soelberg, M; Henriksen, Jens Henrik Sahl

    1992-01-01

    Twenty-nine patients due to have a total hip replacement had their systemic systolic and segmental blood pressures measured prior to operation and 1 and 6 weeks postoperatively. No patients had signs of ischemia. The segmental blood pressure was measured at the ankle and at the toes. A significant...... drop was found in all pressures 1 week postoperatively. The decrease followed the systemic pressure and was restored to normal after 6 weeks. In a group of six patients with preoperatively decreased ankle pressure, a significant transient further decrease in the ankle-toe gradient pressure was found...

  11. IceBridge Paroscientific L0 Pressure Altimeter Raw Air Pressure

    Data.gov (United States)

    National Aeronautics and Space Administration — The NASA IceBridge Paroscientific L0 Pressure Altimeter Raw Air Pressure (IAPRS0) data set contains air pressure readings taken over Antarctica using the...

  12. Pressure safety program Lawrence Livermore National Laboratory

    Energy Technology Data Exchange (ETDEWEB)

    Borzileri, C.; Traini, M.

    1992-10-01

    The Lawrence Livermore National Laboratory (LLNL) is a Research and Development facility. Programs include research in: nuclear weapons, energy, environmental, biomedical, and other DOE funded programs. LLNL is managed by the University of California for the Department of Energy. Many research and development programs require the use of pressurized fluid systems. In the early 1960`s, courses were developed to train personnel to safely work with pressurized systems. These courses served as a foundation for the Pressure Safety Program. The Pressure Safety Program is administered by the Pressure Safety Manager through the Hazards Control Department, and responsibilities include: (1) Pressure Safety course development and training, (2) Equipment documentation, tracking and inspections/retests, (3) Formal and informal review of pressure systems. The program uses accepted codes and standards and closely follows the DOE Pressure Safety Guidelines Manual. This manual was developed for DOE by Lawrence Livermore National Laboratory. The DOE Pressure Safety Guidelines Manual defines five (5) basic elements which constitute this Pressure Safety Program. These elements are: (1) A Pressure Safety Manual, (2) A Safety Committee, (3) Personnel who are trained and qualified, (4) Documentation and accountability for each pressure vessel or system, (5) Control of the selection and the use of high pressure hardware.

  13. Pressure thrust and pressure shock arrestor (mixer-diffusor device)

    International Nuclear Information System (INIS)

    A mixer-diffusor device for use in nuclear reactors to control the heat and pressure energy resulting from an accident is attached to the end of a hollow conduit from which a gaseous medium such as steam is to be expelled under pressure. The end of the hollow conduit is submerged under the surface of a body of liquid such as water. The mixer-diffusor comprises a conical baffle having an apex extending into the open end of the conduit. A skirt member is positioned around the end of the conduit so than an annular opening is formed between the wall of the conduit and one edge of the skirt member. The skirt member is tapered outwardly at essentially the same angle as the taper of the conical baffle. When the gaseous medium is expelled from the end of the conduit, the gaseous medium flows against and over the conical baffle thereby reducing the thrust forces of the conduit. As the gaseous medium passes the edge of the end of the conduit, the gaseous medium tends to suck the liquid through the annular opening. The liquid is then mixed with the gaseous medium causing the gaseous medium to form a plurality of small bubbles which are expelled from the opening between the skirt and the conical member. In this manner, the gaseous medium is substantially mixed and diffused with the liquid. (auth)

  14. Modelling of pressure loads in a pressure suppression pool

    Energy Technology Data Exchange (ETDEWEB)

    Timperi, A.; Chauhan, M.; Paettikangas, T.; Niemi, J. [VTT Technical Research Centre of Finland (Finland)

    2013-06-15

    Rapid collapse of a large steam bubble is analyzed by using CFD and FEM calculations. In addition, a 1D code is written which takes into account the finite condensation rate. The 1D simulations are compared with the PPOOLEX experiment COL-01. By adjusting the condensation rate, the calculated pressure peak near the vent outlet could be made same as in the experiment. Scaling of the measured pressure loads to full-scale is studied by dimensional analyses and by review of the analysis of Sonin (1981). The structural response of containment during chugging is studied by using an FEM of containment with simplified geometry and loading which was created based on experimental data. The results are compared to the case in which desynchronization is absent, and chugging occurs simultaneously in every vent pipe. The desynchronized loading is created by giving random initiation times for chugs out of distribution corresponding to the desynchronization time presented by Kukita and Namatame (1985). CFD simulations of the PPOOLEX experiment MIX-03 were performed. In the experiment, clear chugging behavior was observed. In the simulation, the interphasial surface was much more stable and oscillation occurred at a higher frequency than in the experiment. The differences are likely caused by the turbulence model and too coarse numerical mesh, which causes numerical diffusion. (Author)

  15. Preeclampsia and High Blood Pressure During Pregnancy

    Science.gov (United States)

    ... AQ FREQUENTLY ASKED QUESTIONS FAQ034 PREGNANCY Preeclampsia and High Blood Pressure During Pregnancy • What is high blood pressure? • What is chronic hypertension? • What is gestational hypertension? • ...

  16. Fiber Optic Pressure Sensor Array Project

    Data.gov (United States)

    National Aeronautics and Space Administration — VIP Sensors proposes to develop a Fiber Optic Pressure Sensor Array System for measuring air flow pressure at multiple points on the skin of aircrafts for Flight...

  17. [Effect of dopamine on the portal pressure].

    Science.gov (United States)

    Benko, H; Peschl, L; Schüller, J; Neumayr, A

    1975-01-01

    1. An infusion of 3 gamma/kg/min dopamine causes a significant increase in the renal plasma flow and the glomerulum filtration rate. This dosage does not cause a change of the mean systolic and arterial pressure. This effect may also be observed in patients with hepatic cirrhosis. 2. The wedged hepatic vein pressure, an indicator for the portal pressure, only shows a slight increase (9,46 +/- 9,41%) as compared to the initial pressure produced by the mentioned dose. Measurements of the spleen pulpa pressure, which likewise indicates the portal pressure, showed an increase of pressure up to 100% due to pressing or coughing. 3. If in the case of bleeding oesophageal varices acute renal failure might develop, the advantage of the effect of dopamine in stimulating the blood flow through the kidneys may be considered more important than the minute danger of a slight increase of the portal pressure, which might provoke haemorrhage. PMID:1220517

  18. Measuring Grip Pressure during the Golf Swing.

    Science.gov (United States)

    Budney, David R.

    1979-01-01

    With the use of a special instrumented golf club, grip pressure measurements can be used by the instructor to quantify and discuss the effects of grip pressure in relation to instructional points. (MM)

  19. Pressure Drop Measurements on Distillation Columns

    Institute of Scientific and Technical Information of China (English)

    T.J. Cai; M.R. Resetarits

    2011-01-01

    Pressure drops are of major importance for distillation/absorption columns. This paper mainly discusses how to correctly measure, interpret and use pressure drop data. The possible causes of incorrect pressure drop measurements are studied including the effects of pressure tap dimensions, locations, and vapor condensation etc. The effect of the static head of vapor on the pressure drop data and column pressures is evaluated. Variations of sectional pressure drops along the column are investigated based on the experimental data obtained from commercial size distillation columns at Fractionation Research, Inc. (FRI). For a packed column, it is found that the spacing between the liquid distributor and the top of the bed affects the overall pressure drop measurements, which is confirmed by a fundamental fluid dynamics analysis.

  20. Segmental blood pressure after total hip replacement

    DEFF Research Database (Denmark)

    Gebuhr, Peter Henrik; Soelberg, M; Henriksen, Jens Henrik

    1992-01-01

    Twenty-nine patients due to have a total hip replacement had their systemic systolic and segmental blood pressures measured prior to operation and 1 and 6 weeks postoperatively. No patients had signs of ischemia. The segmental blood pressure was measured at the ankle and at the toes. A significant...... on the operated side. None of the patients had symptoms from the lowered pressure. We conclude that in patients without signs of ischemia, the postoperative segmental pressure decrease is reversible and therefore not dangerous....... drop was found in all pressures 1 week postoperatively. The decrease followed the systemic pressure and was restored to normal after 6 weeks. In a group of six patients with preoperatively decreased ankle pressure, a significant transient further decrease in the ankle-toe gradient pressure was found...

  1. Fiber Optic Pressure Sensor Array Project

    Data.gov (United States)

    National Aeronautics and Space Administration — VIP Sensors proposes to develop a Fiber Optic Pressure Sensor Array for measuring air flow pressure at multiple points on the skin of aircrafts for Flight Load Test...

  2. Effect of ambient pressure on Leidenfrost temperature

    Science.gov (United States)

    Orejon, Daniel; Sefiane, Khellil; Takata, Yasuyuki

    2014-11-01

    The accurate prediction and control of the interaction of liquids with hot surfaces is paramount in numerous areas, including cooling applications. We present results illustrating the effect of ambient pressure on the temperature required for a droplet to levitate over a hot surface, i.e., the Leidenfrost temperature. In the present study the dependence of wetting and levitating temperatures on ambient pressure in a range of subatmospheric pressures is reported. Experimental data indicate that the Leidenfrost temperature decreases with decreasing pressure at subatmospheric pressures. A physical approach for the dependence of Leidenfrost temperature on ambient pressure, based on an analogy with saturation pressure dependence, is proposed. Furthermore, previous literature data for pressures above atmospheric are also included in the analysis to support and validate the proposed approach. In addition, the effect of substrate material, substrate roughness, and type of fluid on the Leidenfrost temperature is discussed.

  3. DASH diet to lower high blood pressure

    Science.gov (United States)

    ... patientinstructions/000770.htm DASH diet to lower high blood pressure To use the sharing features on this page, ... Hypertension. The DASH diet can help lower high blood pressure and cholesterol and other fats in your blood. ...

  4. High Blood Pressure: Keep the Beat Recipes

    Science.gov (United States)

    ... this page please turn Javascript on. Feature: High Blood Pressure Keep the Beat Recipes Past Issues / Fall 2011 ... National Heart, Lung, and Blood Institute To Improve Blood Pressure, Try the DASH Diet If you're one ...

  5. High Blood Pressure: Unique to Older Adults

    Science.gov (United States)

    ... e-newsletter! Aging & Health A to Z High Blood Pressure Hypertension Unique to Older Adults This section provides ... care and improve or maintain quality of life. Blood Pressure Targets are Different for Very Old Adults High ...

  6. High blood pressure and eye disease

    Science.gov (United States)

    ... page: //medlineplus.gov/ency/article/000999.htm High blood pressure and eye disease To use the sharing features ... are sent to the brain. Causes High blood pressure can damage blood vessels in the retina. The higher the blood ...

  7. Blood Pressure Patterns May Predict Stroke Risk

    Science.gov (United States)

    ... blood pressure reading) of more than 6,700 Dutch adults. Participants were ages 55 to 106 and ... stroke or death from other blood pressure-related diseases up to age 80, the study found. Moderately ...

  8. Safety in the use of pressurized suits

    International Nuclear Information System (INIS)

    This Code of Practice describes the procedures relating to the safe operation of Pressurized Suit Areas and their supporting services. It is directed at personnel responsible for the design and/or operation of Pressurized Suit Areas. (author)

  9. Domestic atmospheric pressure thermal deaerators

    Science.gov (United States)

    Egorov, P. V.; Gimmelberg, A. S.; Mikhailov, V. G.; Baeva, A. N.; Chuprakov, M. V.; Grigoriev, G. V.

    2016-04-01

    Based on many years of experience and proven technical solutions, modern atmospheric pressure deaerators of the capacity of 0.4 to 800 t/h were designed and developed. The construction of such deaerators is based on known and explored technical solutions. A two-stage deaeration scheme is applied where the first stage is a jet dripping level (in a column) and the second one is a bubble level (in a tank). In the design of deaeration columns, low-pressure hydraulic nozzles (Δ p heat and mass exchange processes in the apparatus. The use of the two efficient stages in a column and a "flooded" sparger in a tank allows to reliably guarantee the necessary water heating and deaeration. Steam or "superheated" water of the temperature of t ≥ 125°C can be used as the coolant in the deaerators. The commissioning tests of the new deaerator prototypes of the capacity of 800 and 500 t/h in the HPP conditions showed their sustainable, reliable, and efficient work in the designed range of hydraulic and thermal loads. The content of solved oxygen and free carbon dioxide in make-up water after deaerators meets the requirements of State Standard GOST 16860-88, the operating rules and regulations, and the customer's specifications. Based on these results, the proposals were developed on the structure and the design of deaerators of the productivity of more than 800 t/h for the use in circuits of large heating systems and the preparation of feed water to the TPP at heating and industrial-heating plants. The atmospheric pressure thermal deaerators developed at NPO TsKTI with consideration of the current requirements are recommended for the use in water preparation schemes of various power facilities.

  10. Llano puts pressure on drillers

    Energy Technology Data Exchange (ETDEWEB)

    Flatern, R. von

    1998-08-01

    An account of technological achievement in deepwater vertical drilling is given in the first of two articles. EEX`s used the Sedco Forex Omega platform to set a drilling depth record of 26,969 ft in 2600 ft of water in the Gulf of Mexico in June 1998. The second reports on technology to support measurements while drilling used to drill the world`s deepest horizontal well in Italy`s Villafortuna Trecate field. Technological innovations in the field of high-pressure composite drilling riser joints are also noted. (UK)

  11. Pressure transducers for cryogenic liquids

    OpenAIRE

    Pavlovskyy I. V.; Kutrakov A. P.; Maryamova I. I.; Druzhinin A. A.

    2007-01-01

    The developed universal construction of tensoresistive pressure transducer for cryogenic liquids (liquid nitrogen and liquid helium) is described. The study of strain gauges characteristics on the basis of p-type Si whiskers with different boron concentration, mounted on the invar spring elements (beams), in the wide ranges of strain ε=±1,2·10-3 and temperature 4,2-300 К for transducers simulation were carried out. It was shown that using heavily doped silicon strain gages gives the possibili...

  12. Vertebrate pressure-gradient receivers

    DEFF Research Database (Denmark)

    Christensen-Dalsgaard, Jakob

    2011-01-01

    . Recent vertebrates form a continuum from perfect interaural transmission (0 dB in a certain frequency band) and pronounced eardrum directionality (30-40 dB) in the lizards, over somewhat attenuated transmission and limited directionality in birds and frogs, to the strongly attenuated interaural...... transmission and functionally isolated pressure receiver ears in the mammals. Since some of the binaural interaction already takes place at the eardrum in animals with strongly coupled ears, producing enhanced interaural time and level differences, the subsequent neural processing may be simpler. In robotic...

  13. The pressure of hot QCD

    Science.gov (United States)

    Schröder, York

    2016-05-01

    When heated and/or compressed, strongly interacting matter exhibits a rich phase structure. In this talk, I will concentrate on its behavior under variations of the temperature, which is most relevant for phenomenological applications such as in cosmology, heavy-ion collisions, and astrophysics. In particular, effective field theory methods can be used to combine lattice and continuum calculations, in order to obtain high-precision results for the relevant thermodynamic quantities such as the QCD pressure and equation of state. I will discuss the current status of this systematic approach to QCD thermodynamics, and point out the remaining (technical) problems.

  14. Handling Pressures of Community Logic

    DEFF Research Database (Denmark)

    Minbaeva, Dana; Hotho, Jasper; Muratbekova-Touron, Maral;

    2013-01-01

    The paper aims at investigating how in pluralistic societies, such as emerging economies and countries in transition, organizational decision-makers respond to pressures of community logics in non-community settings, such as the work place. We theorize that in non-community settings, social...... relations and interactions with community members can act as social cues that induce and expose individuals to community logics. We subsequently propose that properties of these relations – immediacy and relatedness - will affect individual response strategies towards community logics. We test these ideas...

  15. [Negative pressure wound therapy dressings].

    Science.gov (United States)

    Téot, Luc

    2016-01-01

    There are many different forms of negative pressure wound therapy dressings and it is important to distinguish clearly between each type. They enable the treatment to be adapted to the shape and depth of the wound, its degree of exudation and the persistence of the fibrinous areas on the surface. The machine's traction capacity, measured in mm of mercury (Hg), must be controlled to establish the healing profile: the more powerful the machine and the more contact there is between the foam and the wound, the faster the formation of the granulation tissue. There are many different solutions which are implemented in accordance with the clinical assessment of the wound.

  16. Incisional Negative Pressure Wound Therapy

    DEFF Research Database (Denmark)

    Hyldig, Nana; Vinter, Christina Anne; Bille, Camilla;

    Background: Obese women undergoing caesarean section are at increased risk of surgical wound complications, which may lead to delayed recovery, pain, reduced quality of life, and increased health care cost. The aim of this study is to evaluate the effect of incisional Negative Pressure Wound...... the therapy will be left in situ for five days. In the control group the dressing will be left in situ for at least 24 hours as standard procedure. Follow-up is 30 days. Results: The study is on going. The first 179 participants are about to be analysed. Overall we expect to find a 50% reduction of wound...

  17. The role of nutrition for pressure ulcer management: national pressure ulcer advisory panel, European pressure ulcer advisory panel, and pan pacific pressure injury alliance white paper.

    Science.gov (United States)

    Posthauer, Mary Ellen; Banks, Merrilyn; Dorner, Becky; Schols, Jos M G A

    2015-04-01

    Nutrition and hydration play an important role in preserving skin and tissue viability and in supporting tissue repair for pressure ulcer (PrU) healing. The majority of research investigating the relationship between nutrition and wounds focuses on PrUs. This white paper reviews the 2014 National Pressure Ulcer Advisory Panel, European Pressure Ulcer Advisory Panel, and Pan Pacific Pressure Injury Alliance Nutrition Guidelines and discusses nutrition strategies for PrU management. PMID:25775201

  18. Carbon nanotube temperature and pressure sensors

    Science.gov (United States)

    Ivanov, Ilia N; Geohegan, David Bruce

    2013-10-29

    The present invention, in one embodiment, provides a method of measuring pressure or temperature using a sensor including a sensor element composed of a plurality of carbon nanotubes. In one example, the resistance of the plurality of carbon nanotubes is measured in response to the application of temperature or pressure. The changes in resistance are then recorded and correlated to temperature or pressure. In one embodiment, the present invention provides for independent measurement of pressure or temperature using the sensors disclosed herein.

  19. Carbon nanotube temperature and pressure sensors

    Energy Technology Data Exchange (ETDEWEB)

    Ivanov, Ilia N.; Geohegan, David B.

    2016-10-25

    The present invention, in one embodiment, provides a method of measuring pressure or temperature using a sensor including a sensor element composed of a plurality of carbon nanotubes. In one example, the resistance of the plurality of carbon nanotubes is measured in response to the application of temperature or pressure. The changes in resistance are then recorded and correlated to temperature or pressure. In one embodiment, the present invention provides for independent measurement of pressure or temperature using the sensors disclosed herein.

  20. HIGH BLOOD PRESSURE: DOES THIS CONCERN ME?

    CERN Document Server

    2007-01-01

    To find out, the Medical Service's nurses are organising A HIGH BLOOD PRESSURE SCREENING AND PREVENTION CAMPAIGN from Monday, 26th to Thursday, 29th March 2007 at the Infirmary - Building 57 - ground floor A blood pressure test, advice, information and, if necessary, referral for specialist medical treatment will be offered to any person working on the CERN site. High blood pressure is a stealth threat to health. So come and get your blood pressure checked.

  1. HIGH BLOOD PRESSURE: DOES THIS CONCERN ME?

    CERN Document Server

    2007-01-01

    To find out, the Medical Service's nurses are organising A HIGH BLOOD PRESSURE SCREENING AND PREVENTION CAMPAIGN from Monday, 26th to Thursday, 29th March 2007 at the Infirmary - Building 57 - ground floor A blood pressure test, advice, information and, if necessary, referral for specialist medical treatment will be offered to any person working on the CERN site. High blood pressure is a silent threat to health. So come and get your blood pressure checked.

  2. Pipes under internal pressure and bending

    CERN Document Server

    Catinaccio, A

    2009-01-01

    This article covers the general behaviour of a straight uniform pipe, with built-in open ends, subject to internal pressure and in plane bending or curvature. It is intended as a summary of the basic equations driving the unintuitive phenomena of bending and instability of pipes under internal pressure. The analysis covers in addition the investigation of opposite pressure stabilisation effects that can be observed in some orthotropic material pipes like composite pressure hoses.

  3. High pressure fiber optic sensor system

    Science.gov (United States)

    Guida, Renato; Xia, Hua; Lee, Boon K; Dekate, Sachin N

    2013-11-26

    The present application provides a fiber optic sensor system. The fiber optic sensor system may include a small diameter bellows, a large diameter bellows, and a fiber optic pressure sensor attached to the small diameter bellows. Contraction of the large diameter bellows under an applied pressure may cause the small diameter bellows to expand such that the fiber optic pressure sensor may measure the applied pressure.

  4. Incentive Effects of Peer Pressure in Organizations

    OpenAIRE

    Kohei Daido

    2006-01-01

    This paper studies the effects of peer pressure on incentives. We assume that, in addition to the material payoff, each agent's utility includes the psychological payoff from peer pressure generated by a comparison of effort costs. We show that the optimal incentive schemes depend mainly on the degree of peer pressure and of the heterogeneity of agents. Furthermore, we examine the optimal organizational forms in terms of the principal''s intention to make use of the effects of peer pressure.

  5. Correct sampling of gas condensate reservoir with liquid drop around the well

    OpenAIRE

    Gebremedhin, Okbit

    2014-01-01

    In gas-condensate system for an accurate engineering and science computations such as reserves estimation and well testing and analysing a concrete knowledge of phase and fluid phase behaviour is very significant. In typical gas-condensate reservoirs with the decrease of the flowing bottom-hole pressure below the dew point dramatic decrease in gas production occurs. In presence of high pressure and temperature, there is a much higher tendency of complex organic molecules degradation. The ...

  6. Conformable Pressurized Structures: Design and Analysis

    NARCIS (Netherlands)

    Geuskens, F.J.J.M.M.

    2012-01-01

    There are many applications where volume needs to be pressurised within a geometrical space for which conventional pressure vessels do not provide suitable solutions. Applications are for example found in pressure cabins for Blended Wing Body Aircraft and conformable pressure vessels for an incompre

  7. High Precision Pressure Measurement with a Funnel

    Science.gov (United States)

    Lopez-Arias, T.; Gratton, L. M.; Oss, S.

    2008-01-01

    A simple experimental device for high precision differential pressure measurements is presented. Its working mechanism recalls that of a hydraulic press, where pressure is supplied by insufflating air under a funnel. As an application, we measure air pressure inside a soap bubble. The soap bubble is inflated and connected to a funnel which is…

  8. 46 CFR 154.452 - External pressure.

    Science.gov (United States)

    2010-10-01

    ... tower and piping, the effect of the partially filled tank, the effect of acceleration and hull deflection, and the local effect of external and internal pressure. P4=0, or the external pressure from the... space containing any portion of a pressure vessel. P3=total compressive load in the tank shell from...

  9. Pressure Points: Preventing and Controlling Hypertension

    Science.gov (United States)

    ... pressure," says Appel, a professor at Johns Hopkins University School of Medicine. "Americans should take action before ... of food nutrients on blood pressure. It emphasizes consumption of fruits, ... move is to limit alcohol intake. Excess alcohol can raise blood pressure as ...

  10. 21 CFR 868.2700 - Pressure regulator.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Pressure regulator. 868.2700 Section 868.2700 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL... purposes and that is used to convert a medical gas pressure from a high variable pressure to a lower,...

  11. Pressurized solid oxide fuel cell testing

    Energy Technology Data Exchange (ETDEWEB)

    Basel, R.A.; Pierre, J.F.

    1995-08-01

    The goals of the SOFC pressurized test program are to obtain cell voltage versus current (VI) performance data as a function of pressure; to evaluate the effects of operating parameters such as temperature, air stoichiometry, and fuel utilization on cell performance, and to demonstrate long term stability of the SOFC materials at elevated pressures.

  12. Pressure Transducer Has Long Service Life

    Science.gov (United States)

    Prout, R. E.; Chaves, A. J.

    1982-01-01

    Differential-pressure transducer includes a piston, helical springs, and a linear variable-differential transformer concentric with piston. Transducer senses motion of piston in response to changes in pressure differential. Eight seals within the transducer prevent fluid leakage from one pressure line to the other. Reliability and operating life of the new unit are superior to many conventional transducers.

  13. 49 CFR 229.107 - Pressure gauge.

    Science.gov (United States)

    2010-10-01

    ....107 Pressure gauge. (a) Each steam generator shall have an illuminated steam gauge that correctly... the allowed working pressure of the steam generator. (b) Each steam pressure gauge on a steam generator shall have a siphon that prevents steam from entering the gauge. The pipe connection...

  14. Statistical analysis of silo wall pressures

    DEFF Research Database (Denmark)

    Ditlevsen, Ove Dalager; Berntsen, Kasper Nikolaj

    1998-01-01

    Previously published silo wall pressure measurements during plug flow of barley in alarge concrete silo are re-analysed under the hypothesis that the wall pressures are gamma-distributed.The fits of the gamma distribution type to the local pressure data from each measuring cell are satisfactory.H...

  15. A micromachined pressure/flow sensor

    NARCIS (Netherlands)

    Oosterbroek, R.E.; Lammerink, T.S.J.; Berenschot, J.W.; Krijnen, G.J.M.; Elwenspoek, M.C.; Berg, van den A.

    1999-01-01

    The micromechanical equivalent of a differential pressure flow-sensor, well known in macro mechanics, is discussed. Two separate pressure sensors are used for the device, enabling to measure both, pressure as well as volume flow-rate. An integrated sensor with capacitive read-out as well as a hybrid

  16. Determining Atmospheric Pressure Using a Water Barometer

    Science.gov (United States)

    Lohrengel, C. Frederick, II; Larson, Paul R.

    2012-01-01

    The atmosphere is an envelope of compressible gases that surrounds Earth. Because of its compressibility and nonuniform heating by the Sun, it is in constant motion. The atmosphere exerts pressure on Earth's surface, but that pressure is in constant flux. This experiment allows students to directly measure atmospheric pressure by measuring the…

  17. Probability based calibration of pressure coefficients

    DEFF Research Database (Denmark)

    Hansen, Svend Ole; Pedersen, Marie Louise; Sørensen, John Dalsgaard

    2015-01-01

    not depend on the type of variable action. A probability based calibration of pressure coefficients have been carried out using pressure measurements on the standard CAARC building modelled on scale of 1:383. The extreme pressures measured on the CAARC building model in the wind tunnel have been fitted...

  18. How to care for pressure sores

    Science.gov (United States)

    Pressure ulcer; Bedsore; Decubitus ulcer ... when pressed. This is a sign that a pressure ulcer is forming. The skin may be warm or ... body fat in the crater. Stage IV: The pressure ulcer has become so deep that there is damage ...

  19. 49 CFR 195.108 - External pressure.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 3 2010-10-01 2010-10-01 false External pressure. 195.108 Section 195.108... PIPELINE Design Requirements § 195.108 External pressure. Any external pressure that will be exerted on the pipe must be provided for in designing a pipeline system....

  20. 49 CFR 230.35 - Pressure testing.

    Science.gov (United States)

    2010-10-01

    ..., DEPARTMENT OF TRANSPORTATION STEAM LOCOMOTIVE INSPECTION AND MAINTENANCE STANDARDS Boilers and Appurtenances Pressure Testing of Boilers § 230.35 Pressure testing. The temperature of the steam locomotive boiler shall be raised to at least 70 deg. F any time hydrostatic pressure is applied to the boiler....

  1. Peer Pressure: An Issue That Crosses Generations.

    Science.gov (United States)

    Kittredge, Karen; McCarthy, Alice R.

    2000-01-01

    Recent research on peer pressure shows that: parents are important to teens, today's teens face unique challenges, and teaching teens to say no does not mean losing friends. The paper presents parenting tips for countering peer pressure, noting the influence of adult peer pressure on children. A sidebar examines the right age to start talking to…

  2. 地层水侵入对超临界CO2钻井井筒温度和压力的影响%Influences of formation water invasion on the well bore temperature and pressure in supercritical CO2 drilling

    Institute of Scientific and Technical Information of China (English)

    王海柱; 沈忠厚; 李根生

    2011-01-01

    Aiming to study the influence of formation water invasion on the well bore temperature and pressure in SC-CO2 (supercritical CO2) drilling with coiled tubing, this paper builds up a weilbore flow model with formation water invasion in SC-CO2 drilling with coiled tubing, based on the comprehensive investigation of the influence of viscosity, density, thermal conductivity, isobaric heat capacity and Joule-Thompson coefficient of SC-CO2. The wellbore temperature and pressure distribution were calculated by the method of coupling among these parameters. The results show that the bigger the rate of invaded formation water and the bigger the density of mixed fluid,the bigger the convective heat transfer coefficient in the annulus. Because of the .Joule-Thompson cooling effect caused by nozzle throttling, the annulus mixture fluid density increased abruptly and the convective heat transfer coefficient decreased abruptly at the well depth of about 1 900 m (about 10 m to bottom hole). Meanwhile the wellbore fluid temperature increased with the invasion rate of formation water, and the same Joule-Thompson cooling effect caused the wellbore fluid temperature to decrease abruptly at the well depth of about 1 900 m. Moreover, the wellbore annulus pressure increased with the increasing of invaded formation water quantity, butthe amplitude is not obvious.%为了研究sC-CO(超临界CO)连续油管钻井过程中地层水侵入对井筒温度和压力的影响,在综合考虑CO流体的黏度、密度、导热系数、热容、焦耳-汤姆逊系数等参数影响的基础上,建立了SC-CO连续油管钻井地层水侵入井筒流动模型,并采用各参数相互耦合的方法对井筒温度和压力分布进行了计算.结果表明,地层水侵入速度越大其混合流体密度越高,环空混合流体对流换热系数越大,但由于喷嘴节流产生的焦耳-汤姆逊冷却效应,在井深约1 900 m处(离井底约10 m处)环空混合流体密度突然增大、对流

  3. Simple device to determine the pressure applied by pressure clips for the treatment of earlobe keloids

    Directory of Open Access Journals (Sweden)

    Aashish Sasidharan

    2015-01-01

    Full Text Available Background: Keloids of the ear are common problems. Various treatment modalities are available for the treatment of ear keloids. Surgical excision with intralesional steroid injection along with compression therapy has the least recurrence rate. Various types of devices are available for pressure therapy. Pressure applied by these devices is uncontrolled and is associated with the risk of pressure necrosis. We describe here a simple and easy to use device to measure pressure applied by these clips for better outcome. Objectives: To devise a simple method to measure the pressure applied by various pressure clips used in ear keloid pressure therapy. Materials and Methods: By using a force sensitive resistor (FSR, the pressure applied gets converted into voltage using electrical wires, resistors, capacitors, converter, amplifier, diode, nine-volt (9V cadmium battery and the voltage is measured using a multimeter. The measured voltage is then converted into pressure using pressure voltage graph that depicts the actual pressure applied by the pressure clip. Results: The pressure applied by different clips was variable. The spring clips were adjustable by slight variation in the design whereas the pressure applied by binder clips and magnet discs was not adjustable. Conclusion: The uncontrolled/suboptimal pressure applied by certain pressure clips can be monitored to provide optimal pressure therapy in ear keloid for better outcome.

  4. Triplets pass their pressure test

    CERN Multimedia

    2007-01-01

    All the LHC inner triplets have now been repaired and are in position. The first ones have passed their pressure tests with flying colours. The repaired inner triplet at LHC Point 1, right side (1R). Ranko Ostojic (on the right), who headed the team responsible for repairing the triplets, shows the magnet to Robert Zimmer, President of the University of Chicago and of Fermi Research Alliance, who visited CERN on 20th August.Three cheers for the triplets! All the LHC inner triplets have now been repaired and are in position in the tunnel. Thanks to the mobilisation of a multidisciplinary team from CERN and Fermilab, assisted by the KEK Laboratory and the Lawrence Berkeley National Laboratory (LBNL), a solution has been found, tested, validated and applied. At the end of March this year, one of the inner triplets at Point 5 failed to withstand a pressure test. A fault was identified in the supports of two out of the three quadruple magne...

  5. An inexpensive pressure telemetry system.

    Science.gov (United States)

    Barber, B J; Quillen, E W; Cowley, A W

    1980-10-01

    An inexpensive telemetry system using transducers and recorders commonly available, i.e., Statham and Grass, is described. The direct-current signal of a Statham transducer is applied to a voltage-controlled oscillator, thereby frequency encoding the pressure sensed by the transducer. This encoded signal frequency modulates a Colpitts oscillator, which acts as a radio-frequency oscillator-transmitter in the 88- to 108-MHz band. This transmitter and transducer, along with a rechargeable NiCd battery pack (total wt 0.5 kg), are mounted in a canvas jacket and worn by a dog previously prepared with a chronic indwelling arterial catheter. With a fully charged battery pack, a signal can be transmitted up to 250 ft for 50 h. A frequency-modulation automotive receiver, powered by and interfaced with a Grass 7B recorder, receives the signal and drives a tachometer circuit that reconverts the audio-frequency signal to a voltage proportional to pressure. This voltage is then applied to the driver amplifier of the Grass to produce a charted record. This system introduces no distortion as seen by comparison of direct and telemetered signals and is drift free for intervals exceeding 24 h. PMID:7425148

  6. Atmospheric pressure plasma jet applications

    Energy Technology Data Exchange (ETDEWEB)

    Park, J.; Herrmann, H.W.; Henins, I.; Selwyn, G.S. [Los Alamos National Lab., NM (United States)

    1998-12-31

    The atmospheric pressure plasma jet (APPJ) is a non-thermal, high pressure plasma discharge that produces a high velocity effluent stream of highly reactive chemical species. The discharge operates on a feedstock gas (e.g., He/O2/H2O) which flows between two concentric cylindrical electrodes: an outer grounded electrode and an inner electrode powered at 13.56 MHz RF. While passing through the plasma, the feedgas becomes excited, ionized or dissociated by electron impact. The fast-flowing effluent consists of ions and electrons, which are rapidly lost by recombination, highly reactive radicals (e.g., O, OH), and metastable species (e.g., O2). The metastable O2, which is reactive to hydrocarbon and other organic species, has been observed through optical emission spectroscopy to decrease by a factor of 2 from the APPJ nozzle exit to a distance of 10 cm. Unreacted metastable O2, and that which does not impinge on a surface, will then decay back to ordinary ground state O2, resulting in a completely dry, environmentally-benign form of surface cleaning. Applications such as removal of photoresist, oxide films and organic residues from wafers for the electronics industry, decontamination of civilian and military areas and personnel exposed to chemical or biological warfare agents, and paint (e.g., graffiti) removal are being considered.

  7. Pressures involved in making upper edentulous impressions.

    Science.gov (United States)

    Rihani, A

    1981-12-01

    A study was made of the pressures exerted on the upper denture-bearing area in three patients each with a different type of palatal vault. A method of measuring the relative pressures in different regions of the upper denture bearing area was devised. These pressures were registered with the use of manometers while making an impression in close fitting acrylic resin special trays. The results indicated that the main pressure regions during impression making were near the center of the palate and these pressures diminished toward the buccal borders. PMID:7028974

  8. Pressure transient method for front tracking

    Energy Technology Data Exchange (ETDEWEB)

    Benson, S.M.; Bodvarsson, G.S.

    1983-08-01

    A pressure transient technique for tracking the advance of cold water fronts during water flooding and goethermal injection operations has been developed. The technique is based on the concept that the steady state pressure buildup in the reservoir region inside the front can be calculated by a fluid skin factor. By analyzing successive pressure falloff tests, the advance of the front in the reservoir can be monitored. The validity of the methods is demonstrated by application to three numerically simulated data sets, a nonisothermal step-rate injection test, a series of pressure falloffs in a multilayered reservoir, and a series of pressure falloff tests in a water flooded oil reservoir.

  9. Bulkhead pressure measurements in model fill pours

    Energy Technology Data Exchange (ETDEWEB)

    Mitchell, R.J.; Roettger, J.J.

    1984-08-01

    The results of a series of model stope pours designed to investigate working pressures on bulkheads during hydraulic pouring of classified tailings backfill are reported. Total bulkhead pressures and fill water pressures were monitored under the condition of a fully saturated backfill. Similitude of the model testing is discussed and equations are developed to estimate bulkhead pressures under prototype conditions. The model results show that good base drainage, combined with a bulkhead setback, can reduce the expected bulkhead pressures to values such that timber or concrete block structures should be capable of supporting a saturated backfill.

  10. Ambient Interstellar Pressure and Superbubble Evolution

    CERN Document Server

    Oey, M S

    2004-01-01

    High ambient interstellar pressure is suggested as a possible factor to explain the ubiquitous observed growth-rate discrepancy for supernova-driven superbubbles and stellar wind bubbles. Pressures of P/k ~ 1e5 cm-3 K are plausible for regions with high star formation rates, and these values are intermediate between the estimated Galactic mid-plane pressure and those observed in starburst galaxies. High-pressure components also are commonly seen in Galactic ISM localizations. We demonstrate the sensitivity of shell growth to the ambient pressure, and suggest that superbubbles ultimately might serve as ISM barometers.

  11. Genome-wide association study identifies six new loci influencing pulse pressure and mean arterial pressure

    NARCIS (Netherlands)

    L.V. Wain (Louise); G.C. Verwoert (Germaine); P.F. O'Reilly (Paul); G. Shi (Gang); T. Johnson (Toby); M. Bochud (Murielle); K. Rice (Kenneth); P. Henneman (Peter); A.V. Smith (Albert Vernon); G.B. Ehret (Georg); N. Amin (Najaf); M.G. Larson (Martin); V. Mooser (Vincent); D. Hadley (David); M. Dörr (Marcus); J.C. Bis (Joshua); T. Aspelund (Thor); T. Esko (Tõnu); A.C.J.W. Janssens (Cécile); J.H. Zhao; S.C. Heath (Simon); M. Laan (Maris); J. Fu (Jingyuan); G. Pistis (Giorgio); J. Luan; G. Lucas (Gavin); N. Pirastu (Nicola); I. Pichler (Irene); A.U. Jackson (Anne); R.J. Webster (Rebecca J.); F.F. Zhang; J. Peden (John); R. Schmidt (Reinhold); T. Tanaka (Toshiko); H. Campbell (Harry); W. Igl (Wilmar); Y. Milaneschi (Yuri); J.J. Hottenga (Jouke Jan); V. Vitart (Veronique); D.I. Chasman (Daniel); S. Trompet (Stella); J.L. Bragg-Gresham (Jennifer L.); B.Z. Alizadeh (Behrooz); J.C. Chambers (John); X. Guo (Xiuqing); T. Lehtimäki (Terho); B. Kuhnel (Brigitte); L.M. Lopez; O. Polasek (Ozren); M. Boban (Mladen); C.P. Nelson (Christopher P.); A.C. Morrison (Alanna); V. Pihur (Vasyl); S.K. Ganesh (Santhi); A. Hofman (Albert); S. Kundu (Suman); F.U.S. Mattace Raso (Francesco); F. Rivadeneira Ramirez (Fernando); E.J.G. Sijbrands (Eric); A.G. Uitterlinden (André); S.J. Hwang; R.S. Vasan (Ramachandran Srini); Y.A. Wang (Ying); S.M. Bergmann (Sven); P. Vollenweider (Peter); G. Waeber (Gérard); J. Laitinen (Jaana); A. Pouta (Anneli); P. Zitting (Paavo); W.L. McArdle (Wendy); H.K. Kroemer (Heyo); U. Völker (Uwe); H. Völzke (Henry); N.L. Glazer (Nicole); K.D. Taylor (Kent); T.B. Harris (Tamara); H. Alavere (Helene); T. Haller (Toomas); A. Keis (Aime); M.L. Tammesoo; Y.S. Aulchenko (Yurii); K-T. Khaw (Kay-Tee); P. Galan (Pilar); S. Hercberg (Serge); G.M. Lathrop (Mark); S. Eyheramendy (Susana); E. Org (Elin); S. Sõber (Siim); X. Lu (Xiaowen); I.M. Nolte (Ilja); B.W.J.H. Penninx (Brenda); T. Corre (Tanguy); C. Masciullo (Corrado); C. Sala (Cinzia); L. Groop (Leif); B.F. Voight (Benjamin); O. Melander (Olle); C.J. O'Donnell (Christopher); V. Salomaa (Veikko); A.P. D (Adamo Pio); A. Fabretto (Antonella); F. Faletra (Flavio); S. Ulivi (Shelia); F. Del Greco M (Fabiola); M.F. Facheris (Maurizio); F.S. Collins (Francis); R.N. Bergman (Richard); J.P. Beilby (John); J. Hung; A.W. Musk (Arthur); M. Mangino (Massimo); S.Y. Shin (So Youn); N. Soranzo (Nicole); H. Watkins (Hugh); A. Goel (Anuj); A. Hamsten (Anders); P. Gider (Pierre); M. Loitfelder (Marisa); M. Zeginigg (Marion); D.G. Hernandez (Dena); S.S. Najjar (Samer); P. Navarro (Pau); S.H. Wild (Sarah); A.M. Corsi (Anna Maria); A. Singleton (Andrew); E.J.C. de Geus (Eco); G.A.H.M. Willemsen (Gonneke); A.N. Parker (Alex); L.M. Rose (Lynda); B.M. Buckley (Brendan M.); D.J. Stott (David. J.); M. Orrù (Marco); M. Uda (Manuela); M.M. van der Klauw (Melanie); X. Li (Xiaohui); J. Scott (James); Y.D.I. Chen (Yii-Der Ida); G.L. Burke (Greg); M. Kähönen (Mika); J. Viikari (Jorma); A. Döring (Angela); T. Meitinger (Thomas); G.S. Davis; J.M. Starr (John); V. Emilsson (Valur); A.S. Plump (Andrew); J.H. Lindeman (Jan H.); P.A.C. 't Hoen (Peter); I.R. König (Inke); J.F. Felix (Janine); R. Clarke; J. Hopewell; H. Ongen (Halit); M.M.B. Breteler (Monique); S. Debette (Stéphanie); A.L. DeStefano (Anita); M. Fornage (Myriam); G.F. Mitchell (Gary); H. Holm (Hilma); K. Stefansson (Kari); G. Thorleifsson (Gudmar); U. Thorsteinsdottir (Unnur); N.J. Samani (Nilesh); M. Preuss (Michael); I. Rudan (Igor); C. Hayward (Caroline); I.J. Deary (Ian); H.E. Wichmann (Heinz Erich); O. Raitakari (Olli); W. Palmas (Walter); J.S. Kooner (Jaspal); R.P. Stolk (Ronald); J.W. Jukema (Jan Wouter); A.F. Wright (Alan); D.I. Boomsma (Dorret); S. Bandinelli (Stefania); U. Gyllensten (Ulf); J.F. Wilson (James); L. Ferrucci (Luigi); M. Farrall (Martin); T.D. Spector (Timothy); L.J. Palmer; J. Tuomilehto (Jaakko); A. Pfeufer (Arne); P. Gasparini (Paolo); D.S. Siscovick (David); D. Altshuler (David); R.J.F. Loos (Ruth); D. Toniolo (Daniela); H. Snieder (Harold); C. Gieger (Christian); P. Meneton (Pierre); N.J. Wareham (Nick); B.A. Oostra (Ben); A. Metspalu (Andres); L.J. Launer (Lenore); R. Rettig (Rainer); D.P. Strachan (David); J.S. Beckmann (Jacques); J.C.M. Witteman (Jacqueline); J.A.P. Willems van Dijk (Ko); E.A. Boerwinkle (Eric); M. Boehnke (Michael); P.M. Ridker (Paul); M.R. Järvelin; A. Chakravarti (Aravinda); J. Erdmann (Jeanette); V. Gudnason (Vilmundur); C. Newton-Cheh (Christopher); D. Levy (Daniel); P. Arora (Pankaj); P. Munroe (Patricia); B.M. Psaty (Bruce); M. Caulfield (Mark); D.C. Rao (Dabeeru C.); P. Elliott (Paul); P. Tikka-Kleemola (Päivi); G.R. Abecasis (Gonçalo); I. Barroso (Inês)

    2011-01-01

    textabstractNumerous genetic loci have been associated with systolic blood pressure (SBP) and diastolic blood pressure (DBP) in Europeans. We now report genome-wide association studies of pulse pressure (PP) and mean arterial pressure (MAP). In discovery (N = 74,064) and follow-up studies (N = 48,60

  12. Genome-wide association study identifies six new loci influencing pulse pressure and mean arterial pressure

    NARCIS (Netherlands)

    Wain, Louise V.; Verwoert, Germaine C.; O'Reilly, Paul F.; Shi, Gang; Johnson, Toby; Johnson, Andrew D.; Bochud, Murielle; Rice, Kenneth M.; Henneman, Peter; Smith, Albert V.; Ehret, Georg B.; Amin, Najaf; Larson, Martin G.; Mooser, Vincent; Hadley, David; Doerr, Marcus; Bis, Joshua C.; Aspelund, Thor; Esko, Tonu; Janssens, A. Cecile J. W.; Zhao, Jing Hua; Heath, Simon; Laan, Maris; Fu, Jingyuan; Pistis, Giorgio; Luan, Jian'an; Arora, Pankaj; Lucas, Gavin; Pirastu, Nicola; Pichler, Irene; Jackson, Anne U.; Webster, Rebecca J.; Zhang, Feng; Peden, John F.; Schmidt, Helena; Tanaka, Toshiko; Campbell, Harry; Igl, Wilmar; Milaneschi, Yuri; Hottenga, Jouke-Jan; Vitart, Veronique; Chasman, Daniel I.; Trompet, Stella; Bragg-Gresham, Jennifer L.; Alizadeh, Behrooz Z.; Chambers, John C.; Guo, Xiuqing; Lehtimaki, Terho; Kuehnel, Brigitte; Lopez, Lorna M.; Polasek, Ozren; Boban, Mladen; Nelson, Christopher P.; Morrison, Alanna C.; Pihur, Vasyl; Ganesh, Santhi K.; Hofman, Albert; Kundu, Suman; Mattace-Raso, Francesco U. S.; Rivadeneira, Fernando; Sijbrands, Eric J. G.; Uitterlinden, Andre G.; Hwang, Shih-Jen; Vasan, Ramachandran S.; Wang, Thomas J.; Bergmann, Sven; Vollenweider, Peter; Waeber, Gerard; Laitinen, Jaana; Pouta, Anneli; Zitting, Paavo; McArdle, Wendy L.; Kroemer, Heyo K.; Voelker, Uwe; Voelzke, Henry; Glazer, Nicole L.; Taylor, Kent D.; Harris, Tamara B.; Alavere, Helene; Haller, Toomas; Keis, Aime; Tammesoo, Mari-Liis; Aulchenko, Yurii; Barroso, Ines; Khaw, Kay-Tee; Galan, Pilar; Hercberg, Serge; Lathrop, Mark; Eyheramendy, Susana; Org, Elin; Sober, Siim; Lu, Xiaowen; Nolte, Ilja M.; Penninx, Brenda W.; Corre, Tanguy; Masciullo, Corrado; Sala, Cinzia; Groop, Leif; Voight, Benjamin F.; Melander, Olle; O'Donnell, Christopher J.; Salomaa, Veikko; d'Adamo, Adamo Pio; Fabretto, Antonella; Faletra, Flavio; Ulivi, Sheila; Del Greco, Fabiola M.; Facheris, Maurizio; Collins, Francis S.; Bergman, Richard N.; Beilby, John P.; Hung, Joseph; Musk, A. William; Mangino, Massimo; Shin, So-Youn; Soranzo, Nicole; Watkins, Hugh; Goel, Anuj; Hamsten, Anders; Gider, Pierre; Loitfelder, Marisa; Zeginigg, Marion; Hernandez, Dena; Najjar, Samer S.; Navarro, Pau; Wild, Sarah H.; Corsi, Anna Maria; Singleton, Andrew; de Geus, Eco J. C.; Willemsen, Gonneke; Parker, Alex N.; Rose, Lynda M.; Buckley, Brendan; Stott, David; Orru, Marco; Uda, Manuela; van der Klauw, Melanie M.; Zhang, Weihua; Li, Xinzhong; Scott, James; Chen, Yii-Der Ida; Burke, Gregory L.; Kahonen, Mika; Viikari, Jorma; Doering, Angela; Meitinger, Thomas; Davies, Gail; Starr, John M.; Emilsson, Valur; Plump, Andrew; Lindeman, Jan H.; 't Hoen, Peter A. C.; Koenig, Inke R.; Felix, Janine F.; Clarke, Robert; Hopewell, Jemma C.; Ongen, Halit; Breteler, Monique; Debette, Stephanie; DeStefano, Anita L.; Fornage, Myriam; Mitchell, Gary F.; Smith, Nicholas L.; Holm, Hilma; Stefansson, Kari; Thorleifsson, Gudmar; Thorsteinsdottir, Unnur; Samani, Nilesh J.; Preuss, Michael; Rudan, Igor; Hayward, Caroline; Deary, Ian J.; Wichmann, H-Erich; Raitakari, Olli T.; Palmas, Walter; Kooner, Jaspal S.; Stolk, Ronald P.; Jukema, J. Wouter; Wright, Alan F.; Boomsma, Dorret I.; Bandinelli, Stefania; Gyllensten, Ulf B.; Wilson, James F.; Ferrucci, Luigi; Schmidt, Reinhold; Farrall, Martin; Spector, Tim D.; Palmer, Lyle J.; Tuomilehto, Jaakko; Pfeufer, Arne; Gasparini, Paolo; Siscovick, David; Altshuler, David; Loos, Ruth J. F.; Toniolo, Daniela; Snieder, Harold; Gieger, Christian; Meneton, Pierre; Wareham, Nicholas J.; Oostra, Ben A.; Metspalu, Andres; Launer, Lenore; Rettig, Rainer; Strachan, David P.; Beckmann, Jacques S.; Witteman, Jacqueline C. M.; Erdmann, Jeanette; van Dijk, Ko Willems; Boerwinkle, Eric; Boehnke, Michael; Ridker, Paul M.; Jarvelin, Marjo-Riitta; Chakravarti, Aravinda; Abecasis, Goncalo R.; Gudnason, Vilmundur; Newton-Cheh, Christopher; Levy, Daniel; Munroe, Patricia B.; Psaty, Bruce M.; Caulfield, Mark J.; Rao, Dabeeru C.; Tobin, Martin D.; Elliott, Paul; van Duijn, Cornelia M.

    2011-01-01

    Numerous genetic loci have been associated with systolic blood pressure (SBP) and diastolic blood pressure (DBP) in Europeans(1-3). We now report genome-wide association studies of pulse pressure (PP) and mean arterial pressure (MAP). In discovery (N = 74,064) and follow-up studies (N = 48,607), we

  13. Genome-wide association study identifies six new loci influencing pulse pressure and mean arterial pressure

    NARCIS (Netherlands)

    Wain, Louise V; Verwoert, Germaine C; O'Reilly, Paul F; Shi, Gang; Johnson, Toby; Johnson, Andrew D; Bochud, Murielle; Rice, Kenneth M; Henneman, Peter; Smith, Albert V; Ehret, Georg B; Amin, Najaf; Larson, Martin G; Mooser, Vincent; Hadley, David; Dörr, Marcus; Bis, Joshua C; Aspelund, Thor; Esko, Tõnu; Janssens, A Cecile J W; Zhao, Jing Hua; Heath, Simon; Laan, Maris; Fu, Jingyuan; Pistis, Giorgio; Luan, Jian'an; Arora, Pankaj; Lucas, Gavin; Pirastu, Nicola; Pichler, Irene; Jackson, Anne U; Webster, Rebecca J; Zhang, Feng; Peden, John F; Schmidt, Helena; Tanaka, Toshiko; Campbell, Harry; Igl, Wilmar; Milaneschi, Yuri; Hottenga, Jouke-Jan; Vitart, Veronique; Chasman, Daniel I; Trompet, Stella; Bragg-Gresham, Jennifer L; Alizadeh, Behrooz Z; Chambers, John C; Guo, Xiuqing; Lehtimäki, Terho; Kühnel, Brigitte; Lopez, Lorna M; Polašek, Ozren; Boban, Mladen; Nelson, Christopher P; Morrison, Alanna C; Pihur, Vasyl; Ganesh, Santhi K; Hofman, Albert; Kundu, Suman; Mattace-Raso, Francesco U S; Rivadeneira, Fernando; Sijbrands, Eric J G; Uitterlinden, Andre G; Hwang, Shih-Jen; Vasan, Ramachandran S; Wang, Thomas J; Bergmann, Sven; Vollenweider, Peter; Waeber, Gérard; Laitinen, Jaana; Pouta, Anneli; Zitting, Paavo; McArdle, Wendy L; Kroemer, Heyo K; Völker, Uwe; Völzke, Henry; Glazer, Nicole L; Taylor, Kent D; Harris, Tamara B; Alavere, Helene; Haller, Toomas; Keis, Aime; Tammesoo, Mari-Liis; Aulchenko, Yurii; Barroso, Inês; Khaw, Kay-Tee; Galan, Pilar; Hercberg, Serge; Lathrop, Mark; Eyheramendy, Susana; Org, Elin; Sõber, Siim; Lu, Xiaowen; Nolte, Ilja M; Penninx, Brenda W; Corre, Tanguy; Masciullo, Corrado; Sala, Cinzia; Groop, Leif; Voight, Benjamin F; Melander, Olle; O'Donnell, Christopher J; Salomaa, Veikko; d'Adamo, Adamo Pio; Fabretto, Antonella; Faletra, Flavio; Ulivi, Sheila; Del Greco, Fabiola M; Facheris, Maurizio; Collins, Francis S; Bergman, Richard N; Beilby, John P; Hung, Joseph; Musk, A William; Mangino, Massimo; Shin, So-Youn; Soranzo, Nicole; Watkins, Hugh; Goel, Anuj; Hamsten, Anders; Gider, Pierre; Loitfelder, Marisa; Zeginigg, Marion; Hernandez, Dena; Najjar, Samer S; Navarro, Pau; Wild, Sarah H; Corsi, Anna Maria; Singleton, Andrew; de Geus, Eco J C; Willemsen, Gonneke; Parker, Alex N; Rose, Lynda M; Buckley, Brendan; Stott, David; Orru, Marco; Uda, Manuela; van der Klauw, Melanie M; Zhang, Weihua; Li, Xinzhong; Scott, James; Chen, Yii-Der Ida; Burke, Gregory L; Kähönen, Mika; Viikari, Jorma; Döring, Angela; Meitinger, Thomas; Davies, Gail; Starr, John M; Emilsson, Valur; Plump, Andrew; Lindeman, Jan H; Hoen, Peter A C 't; König, Inke R; Felix, Janine F; Clarke, Robert; Hopewell, Jemma C; Ongen, Halit; Breteler, Monique; Debette, Stéphanie; Destefano, Anita L; Fornage, Myriam; Mitchell, Gary F; Smith, Nicholas L; Holm, Hilma; Stefansson, Kari; Thorleifsson, Gudmar; Thorsteinsdottir, Unnur; Samani, Nilesh J; Preuss, Michael; Rudan, Igor; Hayward, Caroline; Deary, Ian J; Wichmann, H-Erich; Raitakari, Olli T; Palmas, Walter; Kooner, Jaspal S; Stolk, Ronald P; Jukema, J Wouter; Wright, Alan F; Boomsma, Dorret I; Bandinelli, Stefania; Gyllensten, Ulf B; Wilson, James F; Ferrucci, Luigi; Schmidt, Reinhold; Farrall, Martin; Spector, Tim D; Palmer, Lyle J; Tuomilehto, Jaakko; Pfeufer, Arne; Gasparini, Paolo; Siscovick, David; Altshuler, David; Loos, Ruth J F; Toniolo, Daniela; Snieder, Harold; Gieger, Christian; Meneton, Pierre; Wareham, Nicholas J; Oostra, Ben A; Metspalu, Andres; Launer, Lenore; Rettig, Rainer; Strachan, David P; Beckmann, Jacques S; Witteman, Jacqueline C M; Erdmann, Jeanette; van Dijk, Ko Willems; Boerwinkle, Eric; Boehnke, Michael; Ridker, Paul M; Jarvelin, Marjo-Riitta; Chakravarti, Aravinda; Abecasis, Goncalo R; Gudnason, Vilmundur; Newton-Cheh, Christopher; Levy, Daniel; Munroe, Patricia B; Psaty, Bruce M; Caulfield, Mark J; Rao, Dabeeru C; Tobin, Martin D; Elliott, Paul; van Duijn, Cornelia M

    2011-01-01

    Numerous genetic loci have been associated with systolic blood pressure (SBP) and diastolic blood pressure (DBP) in Europeans. We now report genome-wide association studies of pulse pressure (PP) and mean arterial pressure (MAP). In discovery (N = 74,064) and follow-up studies (N = 48,607), we ident

  14. Correlation of invasive central arterial pressure with peripheral arterial pressure and coronary sclerosis

    Institute of Scientific and Technical Information of China (English)

    吴琪

    2013-01-01

    Objective To study the consistency among non-invasive and invasive brachial artery pressure,radial artery pressure and invasive central arterial pressure,and to explore the correlation between the severe degree of coronary artery disease and invasive central aortic pressure.

  15. Change of guinea pig inner ear pressure by square wave middle ear cavity pressure variation

    NARCIS (Netherlands)

    Feijen, RA; Segenhout, JM; Albers, FWJ; Wit, HP

    2002-01-01

    The inner ear fluid pressure of guinea pigs was measured during square wave middle ear cavity pressure variation. Time constants were derived for the slopes of the inner ear pressure recovery curves after middle ear pressure change. A "single exponential" function did not fit well and therefore more

  16. High-pressure study on some superconductors

    CERN Document Server

    Li, K Q; Yao, Y S; Che, G C; Zhao, Z X

    2002-01-01

    High-pressure study has played an important role in the investigation of conventional superconductors. Since the discovery of cuprate superconductors, high-pressure study has become even more important, especially as regards high-pressure synthesis and the effect of pressure. In this report, the new materials Ca-doped Pr-123, (Fe, Cu)-1212, and MgB sub 2 - a very new and interesting system synthesized under high pressure with good quality - will be discussed. Chemical inner pressure has been thought to explain the high T sub c of Ca-doped Pr-123. As another possibility, the replacement of the physical pressure effect by a chemical effect will be discussed.

  17. Glovebox pressure relief and check valve

    Energy Technology Data Exchange (ETDEWEB)

    Blaedel, K.L.

    1986-03-17

    This device is a combined pressure relief valve and check valve providing overpressure protection and preventing back flow into an inert atmosphere enclosure. The pressure relief is embodied by a submerged vent line in a mercury reservior, the releif pressure being a function of the submerged depth. The pressure relief can be vented into an exhaust system and the relieving pressure is only slightly influenced by the varying pressure in the exhaust system. The check valve is embodied by a ball which floats on the mercury column and contacts a seat whenever vacuum exists within the glovebox enclosure. Alternatively, the check valve is embodied by a vertical column of mercury, the maximum back pressure being a function of the height of the column of mercury.

  18. Effect of pressure on biogas production

    Directory of Open Access Journals (Sweden)

    Ahmet ERYAŞAR

    2009-02-01

    Full Text Available In facilities in which biogas systems are installed biogas is not produced and consumed simultaneously. Therefore, biogas produced when there is no consumption should be stored. Low pressure gasometers with 1- 1,5 kPa value are preferred in the rural area and when needed pressurizer is added to the system. When the pressure which gas production and usage require is provided by natural ways without usage of an added pressurizer, a respectively high pressure atmosphere can be seen. In this study, the effects of different low pressures on anaerobic fermentation of cattle manure were experimentally analyzed. Fermentation experiment which was carried out with 9 reactors with fed-batch type, 3 parallels in pressures of 19.6 kPa, 9.5 kPa and 1.5 kPa continued 60 days at 35 ºC. The acquired experimental data was subjected to LSD test in P

  19. Foot Plantar Pressure Measurement System: A Review

    Directory of Open Access Journals (Sweden)

    Yufridin Wahab

    2012-07-01

    Full Text Available Foot plantar pressure is the pressure field that acts between the foot and the support surface during everyday locomotor activities. Information derived from such pressure measures is important in gait and posture research for diagnosing lower limb problems, footwear design, sport biomechanics, injury prevention and other applications. This paper reviews foot plantar sensors characteristics as reported in the literature in addition to foot plantar pressure measurement systems applied to a variety of research problems. Strengths and limitations of current systems are discussed and a wireless foot plantar pressure system is proposed suitable for measuring high pressure distributions under the foot with high accuracy and reliability. The novel system is based on highly linear pressure sensors with no hysteresis.

  20. Interface pressure behavior during painful cuff algometry

    DEFF Research Database (Denmark)

    Khanian, Bahram Manafi; Arendt-Nielsen, Lars; Kjær Petersen, Kristian;

    2016-01-01

    OBJECTIVE: . Cuff algometry is used for the psychophysical assessment of deep-tissue pain sensitivity. The cuff pressure homogeneity may affect the pain sensitivity assessment and potentially be improved by alternative cuff designs optimizing the pressure distribution. The aim of this study was to...... investigate the relationship between pain sensitivity, inflation pressure, and distribution of interface pressure between the skin and cuff during stimulation with a conventional air tourniquet and a novel tourniquet including a water tube interfacing the air cuff with the skin. METHODS: . Air and water cuff...... stimulations were applied separately on the right lower leg of 12 subjects until the tolerance pain threshold. The inflation pressure was controlled and recorded by a computer-control program, while the interface pressure distribution was measured by a flexible pressure sensor mat located between the cuff and...

  1. Bearing pad to pressure tube contact simulation

    Energy Technology Data Exchange (ETDEWEB)

    Talebi, F.; Behdadi, A.; Luxat, J.C., E-mail: farshat@mcmaster.ca, E-mail: behdada@mcmaster.ca, E-mail: luxatj@mcmaster.ca [McMaster Univ., Dept. of Engineering Physics, Hamilton, Ontario (Canada)

    2011-07-01

    Thermal creep strain deformation is a very important pressure tube failure mechanism. During a postulated LOCA (loss of coolant accident) with failure of emergency core injection sys- tem (ECIS), the fuel cladding temperature rapidly increases and the pressure tube becomes completely dry in a few seconds after flow stagnation occurs. Subsequently, the pressure tube circumference is heated by thermal radiation except at the spots where the bearing pads are in direct contact with the pressure tube. Therefore, the localized hot spots are developed on the pressure tube's inner surface under the bearing pads. The main objective of this paper is to evaluate the local thermal-mechanical deformation of a pressure tube in a CANDU reactor and to investigate the fuel channel integrity under localized contact between bearing pad and pressure tube. Furthermore, the mechanistic models are validated against the experimental works per- formed at WRL (Whiteshell research laboratory). Calculations are performed using the finite element method in which the heat, thermal mechanical and creep strain equations are solved, simultaneously. According to the experimental set up, the heat conduction from bearing pads to the inner surface of the pressure tube with appropriate convective and radiation boundary conditions has been simulated. Furthermore, the thermal creep strain deformation has been obtained for when the pressure tube is still under operational condition. It is observed that the pressure tube thermal strain will occur if sufficient high temperature is reached however, depending on the severity of flow degradation in the fuel channel, these localized hot spots could represent a potential creep strain failure of the pressure tube. Whether the pressure tube would fail at these hot spots before contacting the calandria tube depends on the localized temperature and experienced pressure transients. Sensitivity analysis is performed in order to evaluate the contact conductance

  2. Pressure effect on dissimilatory sulfate reduction

    Science.gov (United States)

    Williamson, A. J.; Carlson, H. K.; Coates, J. D.

    2015-12-01

    Biosouring is the production of H2S by sulfate reducing microorganisms (SRM) in-situ or in the produced fluids of oil reservoirs. Sulfide is explosive, toxic and corrosive which can trigger equipment and transportation failure, leading to environmental catastrophe. As oil exploration and reservoir development continue, subsequent enhanced recovery is occurring in progressively deeper formations and typical oil reservoir pressures range from 10-50 MPa. Therefore, an understanding of souring control effects will require an accurate understanding of the influence of pressure on SRM metabolism and the efficacy of souring control treatments at high pressure. Considerable work to date has focussed on souring control at ambient pressure; however, the influence of pressure on biogeochemical processes and souring treatments in oil reservoirs is poorly understood. To explore the impact of pressure on SRM, wild type Desulfovibrio alaskensis G20 (isolated from a producing oil well in Ventura County, California) was grown under a range of pressures (0.1-14 MPa) at 30 °C. Complete sulfate reduction occurred in all pressures tested within 3 days, but microbial growth was inhibited with increasing pressure. Bar-seq identified several genes associated with flagella biosynthesis (including FlhB) and assembly as important for survival at elevated pressure and fitness was confirmed using individual transposon mutants. Flagellar genes have previously been implicated with biofilm formation and confocal microscopy on glass slides incubated with wild type D. alaskensis G20 showed more biomass associated with surfaces under pressure, highlighting the link between pressure, flagellar and biofilm formation. To determine the effect of pressure on the efficacy of SRM inhibitors, IC50 experiments were conducted and D. alaskensis G20 showed a greater resistance to nitrate and the antibiotic chloramphenicol, but a lower resistance to perchlorate. These results will be discussed in the context of

  3. Influence of residual stresses on failure pressure of cylindrical pressure vessels

    Institute of Scientific and Technical Information of China (English)

    M. Jeyakumar; T. Christopher

    2013-01-01

    The utilization of pressure vessels in aerospace applications is manifold. In this work, finite element analysis (FEA) has been carried out using ANSYS software package with 2D axisym-metric model to access the failure pressure of cylindrical pressure vessel made of ASTM A36 carbon steel having weld-induced residual stresses. To find out the effect of residual stresses on failure pressure, first an elasto-plastic analysis is performed to find out the failure pressure of pressure vessel not having residual stresses. Then a thermo-mechanical finite element analysis is performed to assess the residual stresses developed in the pressure vessel during welding. Finally one more elasto-plastic analysis is performed to assess the effect of residual stresses on failure pressure of the pressure vessel having residual stresses. This analysis indicates reduction in the failure pressure due to unfavorable residual stresses.

  4. Noninvasive continuous blood pressure monitoring

    Science.gov (United States)

    Poghosyan, Armen; Mouradian, Vahram; Hovhannisyan, Levon

    2015-03-01

    We are presenting a novel photoplethysmographic (PPG) optical sensor and device with ambient optical, electrical and electromagnetic noises cancellation, thus allowing only the useful optical signals to be received by the health monitoring device. We are also presenting a new processing technique for canceling the ambient noises contributed by optical, electrical and electromagnetic artifacts in the measured PPG signals. Such a device and method allow the enhancement of the performance of the PPG sensors compared to conventional apparatus and methods. The presented sensor and methodology have been integrated into a prototype standalone device for noninvasive, continuous, wearable, remote and mobile monitoring of blood pressure and other human vital signs, such as heart rate, oxygen saturation, respiration rate, etc This small device allows the user to read, store, process and transmit all the measurements made using the PPG optical sensor and the electronic unit to a remote location.

  5. Incisional Negative Pressure Wound Therapy

    DEFF Research Database (Denmark)

    Hyldig, Nana

    the rate of surgical wound infection and wound exudate post-caesarean and that wound infection had a negative impact on quality of life one month after surgery. Alongside the clinical trial, a trial-based cost-effectiveness analysis demonstrated that the treatment is cost-effective in a high......Women with a pre-gestational body mass index (BMI) above 30 kg/m2 giving birth by caesarean section are at high risk of surgical wound infection compared with women with a BMI below 30 kg/m2. Incisional Negative Pressure Wound Therapy (iNPWT) is one strategy to reduce the rate of surgical wound...... infection. However, the treatment is relatively costly compared to standard postoperative dressings and thus it was important to consider the rationale for using iNPWT before introducing the treatment in a clinical setting. This thesis assesses the current evidence of whether iNPWT reduces post...

  6. Swim pressure of active matter

    Science.gov (United States)

    Takatori, Sho; Yan, Wen; Brady, John; Caltech Team

    2014-11-01

    Through their self-motion, all active matter systems generate a unique ``swim pressure'' that is entirely athermal in origin. This new source for the active stress exists at all scales in both living and nonliving active systems, and also applies to larger organisms where inertia is important (i.e., the Stokes number is not small). Here we explain the origin of the swim stress and develop a simple thermodynamic model to study the self-assembly and phase separation in active soft matter. Our new swim stress perspective can help analyze and exploit a wide class of active soft matter, from swimming bacteria and catalytic nanobots, schools of fish and birds, and molecular motors that activate the cellular cytoskeleton.

  7. Nasal continuous positive airway pressure

    DEFF Research Database (Denmark)

    Scholze, Alexandra; Lamwers, Stephanie; Tepel, Martin;

    2012-01-01

    Obstructive sleep apnoea (OSA) is linked to increased cardiovascular risk. This risk can be reduced by nasal continuous positive airway pressure (nCPAP) treatment. As OSA is associated with an increase of several vasoconstrictive factors, we investigated whether nCPAP influences the digital volume...... pulse wave. We performed digital photoplethysmography during sleep at night in 94 consecutive patients who underwent polysomnography and 29 patients treated with nCPAP. Digital volume pulse waves were obtained independently of an investigator and were quantified using an algorithm for continuous.......01; n = 94) and the arousal index (Spearman correlation, r = 0.21; p CPAP treatment, the AHI was significantly reduced from 27 ± 3 events · h(-1) to 4 ± 2 events · h(-1) (each n = 29; p

  8. Anthropic pressures on Egadi Islands

    International Nuclear Information System (INIS)

    The Egadi Islands, like most Mediterranean islets, have radically changed the traditional lifestyle and the economic development model, based for centuries on the almost self-sufficient resources and production activities, mostly related to the sea (fishing and fish processing) and to the land. During the second half of the 1900., the development of transport radically transformed this model to make smaller islands, at least those closest to the coast, more tightly interconnected and dependent on the mainland. In particular, in Favignana, which is the most populous island and very close to the coast, the traditional activities tourism have led to a strong anthropic pressure concentrated in a few months of the year (summer) on the one hand, and a reduction of the resident population during the winter months on the other, with a serious impact on the care of the land

  9. Mini pressurized logistics module (MPLM)

    Science.gov (United States)

    Vallerani, E.; Brondolo, D.; Basile, L.

    1996-06-01

    The MPLM Program was initiated through a Memorandum of Understanding (MOU) between the United States' National Aeronautics and Space Administration (NASA) and Italy's ASI, the Italian Space Agency, that was signed on 6 December 1991. The MPLM is a pressurized logistics module that will be used to transport supplies and materials (up to 20,000 lb), including user experiments, between Earth and International Space Station Alpha (ISSA) using the Shuttle, to support active and passive storage, and to provide a habitable environment for two people when docked to the Station. The Italian Space Agency has selected Alenia Spazio to develop MPLM modules that have always been considered a key element for the new International Space Station taking benefit from its design flexibility and consequent possible cost saving based on the maximum utilization of the Shuttle launch capability for any mission. In the frame of the very recent agreement between the U.S. and Russia for cooperation in space, that foresees the utilization of MIR 1 hardware, the Italian MPLM will remain an important element of the logistics system, being the only pressurized module designed for re-entry. Within the new scenario of anticipated Shuttle flights to MIR 1 during Space Station phase 1, MPLM remains a candidate for one or more missions to provide MIR 1 resupply capabilities and advanced ISSA hardware/procedures verification. Based on the concept of Flexible Carriers, Alenia Spazio is providing NASA with three MPLM flight units that can be configured according to the requirements of the Human-Tended Capability (HTC) and Permanent Human Capability (PHC) of the Space Station. Configurability will allow transportation of passive cargo only, or a combination of passive and cold cargo accommodated in R/F racks. Having developed and qualified the baseline configuration with respect to the worst enveloping condition, each unit could be easily configured to the passive or active version depending upon the

  10. Reactor pressure vessel thermal annealing

    International Nuclear Information System (INIS)

    The steel plates and/or forgings and welds in the beltline region of a reactor pressure vessel (RPV) are subject to embrittlement from neutron irradiation. This embrittlement causes the fracture toughness of the beltline materials to be less than the fracture toughness of the unirradiated material. Material properties of RPVs that have been irradiated and embrittled are recoverable through thermal annealing of the vessel. The amount of recovery primarily depends on the level of the irradiation embrittlement, the chemical composition of the steel, and the annealing temperature and time. Since annealing is an option for extending the service lives of RPVs or establishing less restrictive pressure-temperature (P-T) limits; the industry, the Department of Energy (DOE) and the Nuclear Regulatory Commission (NRC) have assisted in efforts to determine the viability of thermal annealing for embrittlement recovery. General guidance for in-service annealing is provided in American Society for Testing and Materials (ASTM) Standard E 509-86. In addition, the American Society of Mechanical Engineers (ASME) Code Case N-557 addresses annealing conditions (temperature and duration), temperature monitoring, evaluation of loadings, and non-destructive examination techniques. The NRC thermal annealing rule (10 CFR 50.66) was approved by the Commission and published in the Federal Register on December 19, 1995. The Regulatory Guide on thermal annealing (RG 1.162) was processed in parallel with the rule package and was published on February 15, 1996. RG 1.162 contains a listing of issues that need to be addressed for thermal annealing of an RPV. The RG also provides alternatives for predicting re-embrittlement trends after the thermal anneal has been completed. This paper gives an overview of methodology and recent technical references that are associated with thermal annealing. Results from the DOE annealing prototype demonstration project, as well as NRC activities related to the

  11. An eHealth System for Pressure Ulcer Risk Assessment Based on Accelerometer and Pressure Data

    OpenAIRE

    Dieter Hayn; Markus Falgenhauer; Jürgen Morak; Karin Wipfler; Viktoria Willner; Walter Liebhart; Günter Schreier

    2015-01-01

    Pressure ulcers are a common skin disease which is associated with pain, reduced autonomy, social isolation, and reduced quality of life. There are several systems for monitoring of pressure ulcer-related risk factors on the market, but up to now no satisfactory solution is available, especially for people with medium pressure ulcer risk. We present a novel pressure ulcer risk assessment and prevention system, which combines the advantages of accelerometer and pressure sensors for monitoring ...

  12. Comparative Study of Pressure-Induced Germination of Bacillus subtilis Spores at Low and High Pressures

    OpenAIRE

    Wuytack, Elke Y.; Boven, Steven; Michiels, Chris W.

    1998-01-01

    We have studied pressure-induced germination of Bacillus subtilis spores at moderate (100 MPa) and high (500 to 600 MPa) pressures. Although we found comparable germination efficiencies under both conditions by using heat sensitivity as a criterion for germination, the sensitivity of pressure-germinated spores to some other agents was found to depend on the pressure used. Spores germinated at 100 MPa were more sensitive to pressure (>200 MPa), UV light, and hydrogen peroxide than were those g...

  13. Soil pressures at the cutting wheel and the pressure bulkhead of an EPB-shield

    OpenAIRE

    Bezuijen, Adam; Talmon, AM

    2014-01-01

    Soil pressureswere measured on both sides of the cutterwheel of an EPB-shield during tunnelling in saturated sand, using foam for soil conditioning. The measured pressures are compared with the pressures at the pressure bulkhead. The pressures are not purely hydrostatic but the results are also influenced by the yield strength of the foam mixture and the effective stresses. At the lowest positions, the sensors sometimes measured effective stresses. This led to peaks in the pressures measured....

  14. Can subglottal pressure be estimated from intra-oral pressure in speech and singing ?

    OpenAIRE

    Henrich, Nathalie; Lagier, Aude; Amy De La Bretèque, Benoit; Giovanni, Antoine

    2012-01-01

    International audience The direct measurement of subglottal pressure is challenging, because it requires a very invasive approach. It consists in placing a pressure transducer below the glottis by tracheal puncture between the cricoïd cartilage and the trachea first ring. Other methods have been proposed, which estimate the subglottal pressure using less invasive approaches. The most common one is to estimate subglottal pressure from intra-oral pressure measured during the closed phase of ...

  15. Solenoid valves in the pressurizer systems of pressurized water reactors. Magnetventile im Druckhaltesystem von Druckwasserreaktoren

    Energy Technology Data Exchange (ETDEWEB)

    Jocham, H. (Herion-Werke KG, Fellbach (Germany, F.R.))

    1990-07-01

    The safe functioning of the pressurizer system is a very important feature in the safety of the primary systems of nuclear power plants equipped with pressurized water reactors. The decisive units determining the reliability of the pressurizer are the solenoid actuated valves employed as spray systems for pressure control. These spray valves are components of the primary system and, in a way analogous to the reactor pressure vessel, must satisfy the most stringent safety and quality criteria. (orig.).

  16. Pressure equivalents in industrial gas pipelines

    Energy Technology Data Exchange (ETDEWEB)

    Metel' kov, V.P.

    1980-01-01

    Pressure equivalence is a mathematical concept used to explain action and load parameters for pipelines. These two parameters are congruent to pressures encountered in pipelines. The research examined pressure equivalence in 820 by 8 millimeter pipelines in the Samotlor region and took into account the influence of support jams during first and second category jamming. It was determined that the absolute dimensions to pressure pulsations were significantly larger than plus or minus ten percent from (Prab) and even exceeded (Prab) in certain instances. The ratios at which (Prab) can be exceeded vary with relation to the jam supports and the maximum variations stem from yield in the metal pipelines themselves. The above concepts can be used to study the effects of pressure equivalence upon loads and pressures of Samotlor field pipelines and to select appropriate pipeline planning and construction methods. The conclusions drawn are valid for industrial surface pipelines used at below limit pressures. Annular and daily temperature variations in the outside air are considered with regard to their effect upon the pressure equivalence within the lower sections of the pipeline. Deviations here have been noted to exceed (formula). It was observed that in the case of underground pipelines, operated at below limit pressures, pressure equivalence occured in the upper section of the pipeline.

  17. Accuracy of the blood pressure measurement.

    Science.gov (United States)

    Rabbia, F; Del Colle, S; Testa, E; Naso, D; Veglio, F

    2006-08-01

    Blood pressure measurement is the cornerstone for the diagnosis, the treatment and the research on arterial hypertension, and all of the decisions about one of these single aspects may be dramatically influenced by the accuracy of the measurement. Over the past 20 years or so, the accuracy of the conventional Riva-Rocci/Korotkoff technique of blood pressure measurement has been questioned and efforts have been made to improve the technique with automated devices. In the same period, recognition of the phenomenon of white coat hypertension, whereby some individuals with an apparent increase in blood pressure have normal, or reduced, blood pressures when measurement is repeated away from the medical environment, has focused attention on methods of measurement that provide profiles of blood pressure behavior rather than relying on isolated measurements under circumstances that may in themselves influence the level of blood pressure recorded. These methodologies have included repeated measurements of blood pressure using the traditional technique, self-measurement of blood pressure in the home or work place, and ambulatory blood pressure measurement using innovative automated devices. The purpose of this review to serve as a source of practical information about the commonly used methods for blood pressure measurement: the traditional Riva-Rocci method and the automated methods. PMID:17016412

  18. Heated-Pressure-Ball Monopropellant Rocket Engine

    Science.gov (United States)

    Greene, William D.

    2005-01-01

    A recent technology disclosure presents a concept for a monopropellant thermal spacecraft thruster that would feature both the simplicity of a typical prior pressure-fed propellant supply system and the smaller mass and relative compactness of a typical prior pump-fed system. The source of heat for this thruster would likely be a nuclear- fission reactor. The propellant would be a cryogenic fluid (a liquefied low-molecular-weight gas) stored in a tank at a low pressure. The propellant would flow from the tank, through a feedline, into three thick-walled spherical tanks, denoted pressure balls, that would be thermally connected to the reactor. Valves upstream and downstream of the pressure balls would be operated in a three-phase cycle in which propellant would flow into one pressure ball while the fluid underwent pressurization through heating in another ball and pressurized propellant was discharged from the remaining ball into the reactor. After flowing through the reactor, wherein it would be further heated, the propellant would be discharged through an exhaust nozzle to generate thrust. A fraction of the pressurized gas from the pressure balls would be diverted to maintain the desired pressure in the tank.

  19. Modeling and diagnostic techniques applicable to the analysis of pressure noise in pressurized water reactors and pressure-sensing systems

    International Nuclear Information System (INIS)

    Pressure noise data from a PWR are interpreted by means of a computer-implemented model. The model's parameters, namely hydraulic impedances and noise sources, are either calculated or deduced from fits to data. Its accuracy is encouraging and raises the possibility of diagnostic assistance for nuclear plant monitoring. A number of specific applications of pressure noise in the primary system of a PWR and in a pressure sensing system are suggested

  20. Modeling Scala Media as a Pressure Vessel

    Science.gov (United States)

    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.

  1. Pressurized waterproof case for electronic device

    KAUST Repository

    Berumen, Michael L.

    2013-01-31

    The pressurized waterproof case for an electronic device is particularly adapted for the waterproof containment and operation of a touch-screen computer or the like therein at some appreciable water depth. The case may be formed as an enclosure having an open top panel or face covered by a flexible, transparent membrane or the like for the operation of the touch-screen device within the case. A pressurizing system is provided for the case to pressurize the case and the electronic device therein to slightly greater than ambient in order to prevent the external water pressure from bearing against the transparent membrane and pressing it against the touch screen, thereby precluding operation of the touch screen device within the case. The pressurizing system may be a small gas cartridge (e.g., CO2), or may be provided from an external source, such as the diver\\'s breathing air. A pressure relief valve is also provided.

  2. Organic Electroluminescent Sensor for Pressure Measurement

    Directory of Open Access Journals (Sweden)

    Tomohide Niimi

    2012-10-01

    Full Text Available We have proposed a novel concept of a pressure sensor called electroluminescent pressure sensor (ELPS based on oxygen quenching of electroluminescence. The sensor was fabricated as an organic light-emitting device (OLED with phosphorescent dyes whose phosphorescence can be quenched by oxygenmolecules, and with a polymer electrode which permeates oxygen molecules. The sensor was a single-layer OLED with Platinum (II octaethylporphine (PtOEP doped into poly(vinylcarbazole (PVK as an oxygen sensitive emissive layer and poly(3,4-ethylenedioxythiophene mixed with poly(styrenesulfonate (PEDOT:PSS as an oxygen permeating polymer anode. The pressure sensitivity of the fabricated ELPS sample was equivalent to that of the sensor excited by an illumination light source. Moreover, the pressure sensitivity of the sensor is equivalent to that of conventional pressure-sensitive paint (PSP, which is an optical pressure sensor based on photoluminescence.

  3. Beam-induced tensor pressure tokamak equilibria

    International Nuclear Information System (INIS)

    D-shaped tensor pressure tokamak equilibria induced by neutral-beam injection are computed. The beam pressure components are evaluated from the moments of a distribution function that is a solution of the Fokker-Planck equation in which the pitch-angle scattering operator is ignored. The level-psub(perpendicular) contours undergo a significant shift away from the outer edge of the device with respect to the flux surfaces for perpendicular beam injection into broad-pressure-profile equilibria. The psub(parallel) contours undergo a somewhat smaller inward shift with respect to the flux surfaces for both parallel and perpendicular injection into broad-pressure-profile equilibria. For peaked-pressure-profile equilibria, the level pressure contours nearly co-incide with the flux surfaces. (author)

  4. Hydrogen storage in insulated pressure vessels

    Energy Technology Data Exchange (ETDEWEB)

    Aceves, S.M.; Garcia-Villazana, O. [Lawrence Livermore National Lab., CA (United States)

    1998-08-01

    Insulated pressure vessels are cryogenic-capable pressure vessels that can be fueled with liquid hydrogen (LH{sub 2}) or ambient-temperature compressed hydrogen (CH{sub 2}). Insulated pressure vessels offer the advantages of liquid hydrogen tanks (low weight and volume), with reduced disadvantages (lower energy requirement for hydrogen liquefaction and reduced evaporative losses). This paper shows an evaluation of the applicability of the insulated pressure vessels for light-duty vehicles. The paper shows an evaluation of evaporative losses and insulation requirements and a description of the current analysis and experimental plans for testing insulated pressure vessels. The results show significant advantages to the use of insulated pressure vessels for light-duty vehicles.

  5. Seismic induced earth pressures in buried vaults

    International Nuclear Information System (INIS)

    The magnitude and distribution of earth pressures acting on buried structures and induced by a seismic event are considered in this paper. A soil-structure-interaction analysis is performed for typical Department of Energy high level waste storage tanks using a lumped parameter model. The resulting soil pressure distributions are determined and compared with the static soil pressure to assess the design significance of the seismic induced soil pressures. It is found that seismic pressures do not control design unless the peak ground acceleration exceeds about 0.3 G. The effect of soil non linearities (resulting from local soil failure) are also found to have little effect on the predictions of the seismic response of the buried structure. The seismic induced pressures are found to be very similar to those predicted using the elastic model in ASCE 4-86

  6. Commonwealth Edison Company pressure locking test report

    Energy Technology Data Exchange (ETDEWEB)

    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.

  7. Sources of Pressure in Titan's Plasma Environment

    CERN Document Server

    Achilleos, N; Bertucci, C; Guio, P; Romanelli, N; Sergis, N

    2013-01-01

    In order to analyze varying plasma conditions upstream of Titan, we have combined a physical model of Saturn's plasmadisk with a geometrical model of the oscillating current sheet. During modeled oscillation phases where Titan is furthest from the current sheet, the main sources of plasma pressure in the near-Titan space are the magnetic pressure and, for disturbed conditions, the hot plasma pressure. When Titan is at the center of the sheet, the main source is the dynamic pressure associated with Saturn's cold, subcorotating plasma. Total pressure at Titan (dynamic plus thermal plus magnetic) typically increases by a factor of five as the current sheet center is approached. The predicted incident plasma flow direction deviates from the orbital plane of Titan by < 10 deg. These results suggest a correlation between the location of magnetic pressure maxima and the oscillation phase of the plasmasheet.

  8. Classifying bed inclination using pressure images.

    Science.gov (United States)

    Baran Pouyan, M; Ostadabbas, S; Nourani, M; Pompeo, M

    2014-01-01

    Pressure ulcer is one of the most prevalent problems for bed-bound patients in hospitals and nursing homes. Pressure ulcers are painful for patients and costly for healthcare systems. Accurate in-bed posture analysis can significantly help in preventing pressure ulcers. Specifically, bed inclination (back angle) is a factor contributing to pressure ulcer development. In this paper, an efficient methodology is proposed to classify bed inclination. Our approach uses pressure values collected from a commercial pressure mat system. Then, by applying a number of image processing and machine learning techniques, the approximate degree of bed is estimated and classified. The proposed algorithm was tested on 15 subjects with various sizes and weights. The experimental results indicate that our method predicts bed inclination in three classes with 80.3% average accuracy.

  9. Ballooning of CANDU pressure tubes. Model assessment

    International Nuclear Information System (INIS)

    The transient creep equations used to analyze the possible ballooning and failure of Zr-2.5% Nb pressure tubes during a loss-of-coolant accident (LOCA) were developed and verified using as-received Zr-2.5% Nb pressure tube material. But in a CANDU reactor, the pressure tubes absorb deuterium and are exposed to a continuous neutron fluence. Consequently, a literature survey was done to determine how irradiation damage and deuterium might affect the creep rate and ductility of Zr-2.5% Nb pressure tubes in the temperature range from 600 to 800 degrees C. It was found that irradiation damage, dissolved deuterium and deuteride blisters could possibly affect the creep rate and ductility of ZR-2.5% Nb pressure tubes in this temperature range, but deuteride platelets are expected to have little effect. Further tests are required to determine the effect of irradiation damage and deuterium on the creep rate and ductility of pressure tubes

  10. Experimental installation with pressurized fluidized bed boiler

    Energy Technology Data Exchange (ETDEWEB)

    Dobrzanski, W.; Szwarc, W.; Jurek, K.; Prokop, A. (Politechnika Warszawska (Poland). Instytut Techniki Cieplnej)

    1990-01-01

    Describes a test installation with a 3 MW pressurized fluidized bed boiler. The installation was commissioned at the Institute of Heat Engineering at the Technical University in Warsaw. Predesign assumptions and the lay-out of the installation are given. A schematic diagram of the pressurized (0.6 MPa) fluidized bed boiler with an inner diameter of 1.4 m and a total height of 5.45 m is shown. The fuel feeding system consists of a coal and adsorbent container, two feeders and an air jet pump for pneumatic transport. A water type boiler is integrated into the pressure vessel. Flue gas cyclones are also integrated into a separate pressure vessel. The computerized control system and instrumentation are described. Temperatures, pressures, pressure differences, rotational speeds and the chemical composition of gases are monitored.

  11. Commonwealth Edison Company pressure locking test report

    International Nuclear Information System (INIS)

    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

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

    Institute of Scientific and Technical Information of China (English)

    YANG Ben-kun; BIAN Xin-qian; GUO Wei-lai

    2005-01-01

    A pressurizer is one of important equipment in a pressurized water reactor plant. It is used to maintain the pressure of primary coolant within allowed range because the sharp change of coolant pressure affects the security of reactor,therefor,the study of pressurizer's pressure control methods is very important. In this paper, an adaptive fuzzy controller is presented for pressure control of a pressurizer in a nuclear power plant. The controller can on-line tune fuzzy control rules and parameters by self-learning in the actual control process, which possesses the way of thinking like human to make a decision. The simulation results for a pressurized water reactor plant show that the adaptive fuzzy controller has optimum and intelligent characteristics, which prove the controller is effective.

  13. Treatment of refractory low-pressure hydrocephalus with an active pumping negative-pressure shunt system.

    Science.gov (United States)

    Kalani, M Yashar S; Turner, Jay D; Nakaji, Peter

    2013-03-01

    Low-pressure hydrocephalus is a rare type of hydrocephalus characterized by negative intracranial pressure (ICP) and ventriculomegaly. Given the shortcomings of available methods to treat refractory low-pressure hydrocephalus, we set out to develop a new system for evacuation of cerebrospinal fluid (CSF) from the ventricular system where existing shunt systems do not produce the necessary gradient for CSF drainage. We retrospectively reviewed the charts of two patients with the diagnosis of negative-pressure hydrocephalus refractory to traditional treatments. We combined a traditional low-pressure, non-siphoning valve with a pumping chamber placed distal to the valve to create a system that could be actively pumped to remove excess CSF. Treatment of negative-pressure hydrocephalus requires the establishment of a lower ventricular drainage pressure than the drainage pressure in the subarachnoid space. In refractory cases, we propose the use of this active negative-pressure pumping system.

  14. Pressure ulcers: Back to the basics

    OpenAIRE

    Karoon Agrawal; Neha Chauhan

    2012-01-01

    Pressure ulcer in an otherwise sick patient is a matter of concern for the care givers as well as the medical personnel. A lot has been done to understand the disease process. So much so that USA and European countries have established advisory panels in their respective continents. Since the establishment of these organizations, the understanding of the pressure ulcer has improved significantly. The authors feel that the well documented and well publicized definition of pressure ulcer is som...

  15. Fiber bundle model under fluid pressure

    Science.gov (United States)

    Amitrano, David; Girard, Lucas

    2016-03-01

    Internal fluid pressure often plays an important role in the rupture of brittle materials. This is a major concern for many engineering applications and for natural hazards. More specifically, the mechanisms through which fluid pressure, applied at a microscale, can enhance the failure at a macroscale and accelerate damage dynamics leading to failure remains unclear. Here we revisit the fiber bundle model by accounting for the effect of fluid under pressure that contributes to the global load supported by the fiber bundle. Fluid pressure is applied on the broken fibers, following Biot's theory. The statistical properties of damage avalanches and their evolution toward macrofailure are analyzed for a wide range of fluid pressures. The macroscopic strength of the new model appears to be strongly controlled by the action of the fluid, particularly when the fluid pressure becomes comparable with the fiber strength. The behavior remains consistent with continuous transition, i.e., second order, including for large pressure. The main change concerns the damage acceleration toward the failure that is well modeled by the concept of sweeping of an instability. When pressure is increased, the exponent β characterizing the power-law distribution avalanche sizes significantly decreases and the exponent γ characterizing the cutoff divergence when failure is approached significantly increases. This proves that fluid pressure plays a key role in failure process acting as destabilization factor. This indicates that macrofailure occurs more readily under fluid pressure, with a behavior that becomes progressively unstable as fluid pressure increases. This may have considerable consequences on our ability to forecast failure when fluid pressure is acting.

  16. Fiber bundle model under fluid pressure.

    Science.gov (United States)

    Amitrano, David; Girard, Lucas

    2016-03-01

    Internal fluid pressure often plays an important role in the rupture of brittle materials. This is a major concern for many engineering applications and for natural hazards. More specifically, the mechanisms through which fluid pressure, applied at a microscale, can enhance the failure at a macroscale and accelerate damage dynamics leading to failure remains unclear. Here we revisit the fiber bundle model by accounting for the effect of fluid under pressure that contributes to the global load supported by the fiber bundle. Fluid pressure is applied on the broken fibers, following Biot's theory. The statistical properties of damage avalanches and their evolution toward macrofailure are analyzed for a wide range of fluid pressures. The macroscopic strength of the new model appears to be strongly controlled by the action of the fluid, particularly when the fluid pressure becomes comparable with the fiber strength. The behavior remains consistent with continuous transition, i.e., second order, including for large pressure. The main change concerns the damage acceleration toward the failure that is well modeled by the concept of sweeping of an instability. When pressure is increased, the exponent β characterizing the power-law distribution avalanche sizes significantly decreases and the exponent γ characterizing the cutoff divergence when failure is approached significantly increases. This proves that fluid pressure plays a key role in failure process acting as destabilization factor. This indicates that macrofailure occurs more readily under fluid pressure, with a behavior that becomes progressively unstable as fluid pressure increases. This may have considerable consequences on our ability to forecast failure when fluid pressure is acting. PMID:27078437

  17. High pressure processing for food safety.

    Science.gov (United States)

    Fonberg-Broczek, Monika; Windyga, B; Szczawiński, J; Szczawińska, M; Pietrzak, D; Prestamo, G

    2005-01-01

    Food preservation using high pressure is a promising technique in food industry as it offers numerous opportunities for developing new foods with extended shelf-life, high nutritional value and excellent organoleptic characteristics. High pressure is an alternative to thermal processing. The resistance of microorganisms to pressure varies considerably depending on the pressure range applied, temperature and treatment duration, and type of microorganism. Generally, Gram-positive bacteria are more resistant to pressure than Gram-negative bacteria, moulds and yeasts; the most resistant are bacterial spores. The nature of the food is also important, as it may contain substances which protect the microorganism from high pressure. This article presents results of our studies involving the effect of high pressure on survival of some pathogenic bacteria -- Listeria monocytogenes, Aeromonas hydrophila and Enterococcus hirae -- in artificially contaminated cooked ham, ripening hard cheese and fruit juices. The results indicate that in samples of investigated foods the number of these microorganisms decreased proportionally to the pressure used and the duration of treatment, and the effect of these two factors was statistically significant (level of probability, P high pressure treatment than L. monocytogenes and A. hydrophila. Mathematical methods were applied, for accurate prediction of the effects of high pressure on microorganisms. The usefulness of high pressure treatment for inactivation of microorganisms and shelf-life extention of meat products was also evaluated. The results obtained show that high pressure treatment extends the shelf-life of cooked pork ham and raw smoked pork loin up to 8 weeks, ensuring good micro-biological and sensory quality of the products.

  18. On the abdominal pressure volume relationship

    OpenAIRE

    Mulier, Jan Paul; Dillemans, Bruno; Crombach, Mark; Missant, Carlo; Sels, Annabel

    2009-01-01

    Abstract: During insufflation of the abdomen to create a pneumoperitoneum for laparoscopy, both intra abdominal pressure and insufflated volume can be measured and are used to calculate the abdominal pressure-volume relationship. First, an accurate, linear relationship was identified using a mathematical model with an elastance, E, or its reciprocal the compliance C and with a pressure at zero volume, PV0. This function was stable and could be used to describe the abdominal characteristics of...

  19. A ferrofluid-based wireless pressure sensor

    OpenAIRE

    Chitnis, Girish; Ziaie, Babak

    2013-01-01

    This paper presents a wireless pressure sensor design based on magnetic fluid displacement over a planar coil and its corresponding inductance change. The design of the pressure sensor is presented followed by its fabrication and characterization. Experimental results show a good correlation with a nonlinear model relating the applied pressure to the change in coil self-resonant frequency. A prototype sensor (radius = 6 mm, thickness = 2 mm) based on the above principal using an oil-based fer...

  20. Management of patients with pressure ulcers

    OpenAIRE

    Bora Ozel

    2014-01-01

    A pressure ulcer is an area of localized damage to the skin and underlying tissue caused by pressure or shear. Although these ulcers can occur anywhere on the body, they are often located in the ischial, trochanteric, sacral areas and. heel. These ulcers are primarily the products of a combination of pressure and decreased angiogenic response. Early intervention and comprehensive treatment should result in complete healing of ulcers. In this review, we tried to create a general perspective ab...

  1. Life style as a blood pressure determinant.

    OpenAIRE

    Staessen, J A; Bieniaszewski, L; Pardaens, K; V. Petrov; Thijs, L.; Fagard, R.

    1996-01-01

    In Belgium, an affluent Western European country, participation in sports, alcohol intake, and living in a working class area were identified as the life style factors with the closest associations with the blood pressure level. Obesity was another important blood pressure correlate. Sodium intake, determined from the 24 h urinary output, and smoking were not associated with blood pressure. Controlled intervention studies have proven that weight reduction, endurance training and alcohol absti...

  2. Blood vessels, circulation and blood pressure.

    Science.gov (United States)

    Hendry, Charles; Farley, Alistair; McLafferty, Ella

    This article, which forms part of the life sciences series, describes the vessels of the body's blood and lymphatic circulatory systems. Blood pressure and its regulatory systems are examined. The causes and management of hypertension are also explored. It is important that nurses and other healthcare professionals understand the various mechanisms involved in the regulation of blood pressure to prevent high blood pressure or ameliorate its damaging consequences.

  3. Negative pressure wound therapy: clinical utility

    OpenAIRE

    Sandoz H

    2015-01-01

    Heidi Sandoz Accelerate CIC, Mile End Hospital, London, UK Abstract: Negative pressure wound therapy (NPWT), also known as topical negative pressure therapy, has been increasingly used in health care for the management of a wide variety of wounds over the last 2–3 decades. It is an advanced therapy that can be helpful to accelerate wound healing in both acute and chronic wounds by delivering negative pressure (suction) to the wound bed. More recent advancements in the application o...

  4. Blood Pressure Percentiles for School Children

    OpenAIRE

    İsmail Özanli; Sebahat Tülpar; Yunus Yılmaz; Fatih Yıldız

    2016-01-01

    Objective: The prevalence of hypertension in childhood and adolescence is gradually increasing. We aimed to in­vestigate the blood pressure (BP) values of children aged 7-18 years. Methods: This study was conducted in a total of 3375 (1777 females, 1598 males) children from 27 schools. Blood pressures of children were measured using sphyg­momanometer appropriate to arm circumference. Results: A positive relationship was found between sys­tolic blood pressure (SBP) and diastolic blood pr...

  5. Rotor/Stator Unsteady Pressure Interaction

    OpenAIRE

    Brennen, C. E.; Franz, R.; Arndt, N.

    1988-01-01

    This paper describes an investigation of rotor/stator interaction in centrifugal pumps with radial diffusers. Steady and unsteady diffuser vane pressure measurements were made for two impellers, one half of the double suction pump of the High Pressure Oxygen Turbopump (HPOTP) of the Space Shuttle Main Engine (SSME) and a two-dimensional impeller. Unsteady impeller blade pressure measurements were made for a second two-dimensional impeller with blade number and geometry identical to the two-di...

  6. Home blood pressure monitoring for mild hypertensives.

    OpenAIRE

    Midanik, L T; Resnick, B; Hurley, L B; Smith, E J; Mccarthy, M.

    1991-01-01

    A clinical trial of 204 untreated patients with mild hypertension was conducted to assess the effect of home blood pressure monitoring on blood pressure level, pharmacologic treatment, reduction of risk factors, and use of health services. After 1 year, no statistically significant differences were found between the treatment and control groups. The findings indicate that, while home blood pressure monitoring may be useful, it has no measurable short-term impact on these aspects of blood pres...

  7. 'Peer pressure' in larval Drosophila?

    Science.gov (United States)

    Niewalda, Thomas; Jeske, Ines; Michels, Birgit; Gerber, Bertram

    2014-01-01

    Understanding social behaviour requires a study case that is simple enough to be tractable, yet complex enough to remain interesting. Do larval Drosophila meet these requirements? In a broad sense, this question can refer to effects of the mere presence of other larvae on the behaviour of a target individual. Here we focused in a more strict sense on 'peer pressure', that is on the question of whether the behaviour of a target individual larva is affected by what a surrounding group of larvae is doing. We found that innate olfactory preference of a target individual was neither affected (i) by the level of innate olfactory preference in the surrounding group nor (ii) by the expression of learned olfactory preference in the group. Likewise, learned olfactory preference of a target individual was neither affected (iii) by the level of innate olfactory preference of the surrounding group nor (iv) by the learned olfactory preference the group was expressing. We conclude that larval Drosophila thus do not take note of specifically what surrounding larvae are doing. This implies that in a strict sense, and to the extent tested, there is no social interaction between larvae. These results validate widely used en mass approaches to the behaviour of larval Drosophila. PMID:24907371

  8. Familial idiopathic normal pressure hydrocephalus.

    Science.gov (United States)

    Huovinen, Joel; Kastinen, Sami; Komulainen, Simo; Oinas, Minna; Avellan, Cecilia; Frantzen, Janek; Rinne, Jaakko; Ronkainen, Antti; Kauppinen, Mikko; Lönnrot, Kimmo; Perola, Markus; Pyykkö, Okko T; Koivisto, Anne M; Remes, Anne M; Soininen, Hilkka; Hiltunen, Mikko; Helisalmi, Seppo; Kurki, Mitja; Jääskeläinen, Juha E; Leinonen, Ville

    2016-09-15

    Idiopathic normal pressure hydrocephalus (iNPH) is a late-onset surgically alleviated, progressive disease. We characterize a potential familial subgroup of iNPH in a nation-wide Finnish cohort of 375 shunt-operated iNPH-patients. The patients were questionnaired and phone-interviewed, whether they have relatives with either diagnosed iNPH or disease-related symptomatology. Then pedigrees of all families with more than one iNPH-case were drawn. Eighteen patients (4.8%) from 12 separate pedigrees had at least one shunt-operated relative whereas 42 patients (11%) had relatives with two or more triad symptoms. According to multivariate logistic regression analysis, familial iNPH-patients had up to 3-fold risk of clinical dementia compared to sporadic iNPH patients. This risk was independent from diagnosed Alzheimer's disease and APOE ε4 genotype. This study describes a familial entity of iNPH offering a novel approach to discover the potential genetic characteristics of iNPH. Discovered pedigrees offer an intriguing opportunity to conduct longitudinal studies targeting potential preclinical signs of iNPH. PMID:27538594

  9. Intelligent pressure measurement in multiple sensor arrays

    International Nuclear Information System (INIS)

    Pressure data acquisition has typically consisted of a group of sensors scanned by an electronic or mechanical multiplexer. The data accuracy was dependent upon the temperature stability of the sensors. This paper describes a new method of pressure measurement that combines individual temperature compensated pressure sensors, a microprocessor, and an A/D converter in one module. Each sensor has its own temperature characteristics stored in a look-up table to minimize sensor thermal errors. The result is an intelligent pressure module that can output temperature compensated engineering units over an Ethernet interface. Calibration intervals can be dramatically extended depending upon system accuracy requirements and calibration techniques used

  10. Osmosis at constant volume. Negative pressure

    CERN Document Server

    Zupanovic, Pasko; Brumen, Milan; Fajmut, Ales; Juretic, Davor

    2009-01-01

    A thermodynamic state of solvent and solution separated with an elastic semipermeable membrane, in the box with a fixed volume, is considered. It is shown that the minimum of the free energy is accompanied by the compression of the solution and tension of the solvent caused by the transfer of solvent molecules into compartment with solution. The tensile state of the solvent is described in terms of negative pressure. It is found that the negative pressure as well as compression pressure is of the order of osmotic pressure given by van't Hoff equation. It is proposed that this mechanism could be responsible for the water uptake in tall trees.

  11. Vacuum-sealed casting process under pressure

    Institute of Scientific and Technical Information of China (English)

    LI Chen-xi; GUO Tai-ming; WU Chun-jing; WANG Hong

    2006-01-01

    A new casting method, the vacuum-sealed mold casting under pressure, has been developed, and thin wall iron castings with high precision and smooth surface have been produced successfully with this casting method. The experimental results show that the liquid iron has a very excellent filling ability because a high negative pressure is formed in the mold cavity during filling process. The vacuum-sealed mold under pressure has very high compressive strength greater than 650 kPa, which is 3-4 times as high as that of the molds produced by high-pressure molding process or vacuum-sealed molding process.

  12. Beam Loss Diagnostics Based on Pressure Measurements

    CERN Document Server

    Weinrich, U

    2003-01-01

    The GSI is operating a heavy ion synchrotron, which is currently undergoing an upgrade towards higher beam intensities. It was discovered that beam losses induce a significant pressure increase in the vacuum system. In order to detect the time constants of the pressure increase and decrease, fast total pressure measurements were put into operation. With the recently installed partial pressure diagnostics it is also possible to follow up which types of molecules are released. The presentation will focus on the different techniques applied as well as on some measurement results. The potential and difficulties of this diagnostic tool will also be discussed.

  13. Techniques in high pressure neutron scattering

    CERN Document Server

    Klotz, Stefan

    2013-01-01

    Drawing on the author's practical work from the last 20 years, Techniques in High Pressure Neutron Scattering is one of the first books to gather recent methods that allow neutron scattering well beyond 10 GPa. The author shows how neutron scattering has to be adapted to the pressure range and type of measurement.Suitable for both newcomers and experienced high pressure scientists and engineers, the book describes various solutions spanning two to three orders of magnitude in pressure that have emerged in the past three decades. Many engineering concepts are illustrated through examples of rea

  14. Pressure ulcer prevention in frail older people.

    Science.gov (United States)

    Barry, Maree; Nugent, Linda

    2015-12-16

    Pressure ulcers are painful and cause discomfort, have a negative effect on quality of life, and are costly to treat. The incidence and severity of preventable pressure ulcers is an important indicator of quality of care; it is essential that healthcare providers monitor prevalence and incidence rates to ensure that care strategies implemented are effective. Frail older people are at increased risk of developing pressure ulcers. This article discusses the complexities of preventing pressure ulcers in frail older people and emphasises the importance of structured educational programmes that incorporate effective clinical leadership and multidisciplinary teamwork. PMID:26669407

  15. Ideal bulk pressure of active Brownian particles

    Science.gov (United States)

    Speck, Thomas; Jack, Robert L.

    2016-06-01

    The extent to which active matter might be described by effective equilibrium concepts like temperature and pressure is currently being discussed intensely. Here, we study the simplest model, an ideal gas of noninteracting active Brownian particles. While the mechanical pressure exerted onto confining walls has been linked to correlations between particles' positions and their orientations, we show that these correlations are entirely controlled by boundary effects. We also consider a definition of local pressure, which describes interparticle forces in terms of momentum exchange between different regions of the system. We present three pieces of analytical evidence which indicate that such a local pressure exists, and we show that its bulk value differs from the mechanical pressure exerted on the walls of the system. We attribute this difference to the fact that the local pressure in the bulk does not depend on boundary effects, contrary to the mechanical pressure. We carefully examine these boundary effects using a channel geometry, and we show a virial formula for the pressure correctly predicts the mechanical pressure even in finite channels. However, this result no longer holds in more complex geometries, as exemplified for a channel that includes circular obstacles.

  16. High Chamber Pressure, Light Weight Thrusters Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The performance liquid propellant engines can be significantly improved by increasing both combustion temperature and pressure and reducing engine weight. State of...

  17. Transient study of a PWR pressurizer

    International Nuclear Information System (INIS)

    An appropriate method for the calculation and transient performance of the pressurizer of a pressurized water reactor is presented. The study shows a digital program of simulation of pressurizer dynamics based on the First Law of Thermodynamic and Laws of Heat and Mass Transfer. The importance of the digital program that was written for a pressurizer of PWR, lies in the fact that, this can be of practical use in the safety analysis of a reactor of Angra dos Reis type with a power of about 500 M We. (author)

  18. Let's Talk about High Blood Pressure and Stroke

    Science.gov (United States)

    ... Tools & Resources Stroke More Let's Talk About High Blood Pressure and Stroke Updated:Dec 9,2015 What is ... Blood Pressure? How Can I Reduce High Blood Pressure? High Blood Pressure and Stroke What Is Diabetes and How ...

  19. Cells under pressure - treatment of eukaryotic cells with high hydrostatic pressure, from physiologic aspects to pressure induced cell death.

    Science.gov (United States)

    Frey, Benjamin; Janko, Christina; Ebel, Nina; Meister, Silke; Schlücker, Eberhard; Meyer-Pittroff, Roland; Fietkau, Rainer; Herrmann, Martin; Gaipl, Udo S

    2008-01-01

    The research on high hydrostatic pressure in medicine and life sciences is multifaceted. According to the used pressure head the research has to be divided into two different parts. To study physiological aspects of pressure on eukaryotic cells physiological pressure (pHHP; highly reversible alterations and normally does not affect cellular viability. The treatment of eukaryotic cells with non-physiological pressure (HHP; > or = 100 MPa) reveals different outcomes. Treatment with HHP or = 200 MPa. Moreover, HHP treatment with > 300 MPa leads to necrosis. Therefore, HHP plays a role for the sterilisation of human transplants, of food stuff, and pharmaceuticals. Human tumour cells subjected to HHP > 300 MPa display a necrotic phenotype along with a gelificated cytoplasm, preserve their shape, and retain their immunogenicity. These observations favour the use of HHP to produce whole cell based tumour vaccines. Further experiments revealed that the increment of pressure as well as the pressure holding time influences the cell death of tumour cells. We conclude that high hydrostatic pressure offers both, an economic, easy to apply, clean, and fast technique for the generation of vaccines, and a promising tool to study physiological aspects.

  20. Impact of Moisture on the Pressure Delivering Potential of Pressure Garments.

    Science.gov (United States)

    Macintyre, Lisa; Dahale, Monali; Rae, Michelle

    2016-01-01

    Pressure garments are the main method of treatment and prophylaxis for hypertrophic burn scars. The pressure they exert on the scarred skin prevents contractures forming, reduces the itchiness and pruritus associated with active hypertrophic scars, and is believed, by many, to hasten normalization of the scar tissue. The pressure exerted is believed to be critical to treatment success and can be predicted based on laboratory measurement of the fabric's tension profile. All previous research on the pressures delivered by pressure garments has been undertaken using dry fabrics in either laboratory or clinical conditions. However, many patients have complained of increased perspiration when wearing pressure garments, and many burn victims live and work in hot conditions where high levels of perspiration may be expected. This article investigated the impact of moisture content on fabric tension and thus the pressure exerting ability of pressure garments. Four different fabrics currently used in the construction of pressure garments were evaluated in seven different states of "wetness" from completely dry to completely saturated in water or artificial perspiration. Standard laboratory methods were used to measure the initial tension in fabrics and the tension after 11 cycles of extension. Pressures that would be exerted by these fabrics were calculated using the Laplace law. The results of this study showed that the tension, and therefore pressure delivering ability, of fabrics used in pressure garments was significantly reduced when they were wet but that the amount or type of "wetness" did not have a significant effect on pressure delivering ability. PMID:26171677

  1. Pressure distension in leg vessels as influenced by prolonged bed rest and a pressure habituation regimen.

    Science.gov (United States)

    Eiken, Ola; Mekjavic, Igor B; Kounalakis, Stylianos N; Kölegård, Roger

    2016-06-15

    Bed rest increases pressure distension in arteries, arterioles, and veins of the leg. We hypothesized that bed-rest-induced deconditioning of leg vessels is governed by the removal of the local increments in transmural pressure induced by assuming erect posture and, therefore, can be counteracted by intermittently increasing local transmural pressure during the bed rest. Ten men underwent 5 wk of horizontal bed rest. A subatmospheric pressure (-90 mmHg) was intermittently applied to one lower leg [pressure habituation (PH) leg]. Vascular pressure distension was investigated before and after the bed rest, both in the PH and control (CN) leg by increasing local distending pressure, stepwise up to +200 mmHg. Vessel diameter and blood flow were measured in the posterior tibial artery and vessel diameter in the posterior tibial vein. In the CN leg, bed rest led to 5-fold and 2.7-fold increments (P pressure-distension and flow responses, respectively, and to a 2-fold increase in tibial vein pressure distension. In the PH leg, arterial pressure-distension and flow responses were unaffected by bed rest, whereas bed rest led to a 1.5-fold increase in venous pressure distension. It thus appears that bed-rest-induced deconditioning of leg arteries, arterioles, and veins is caused by removal of gravity-dependent local pressure loads and may be abolished or alleviated by a local pressure-habituation regimen.

  2. Application of High Pressure in Food Processing

    Directory of Open Access Journals (Sweden)

    Herceg, Z.

    2011-01-01

    Full Text Available In high pressure processing, foods are subjected to pressures generally in the range of 100 – 800 (1200 MPa. The processing temperature during pressure treatments can be adjusted from below 0 °C to above 100 °C, with exposure times ranging from a few seconds to 20 minutes and even longer, depending on process conditions. The effects of high pressure are system volume reduction and acceleration of reactions that lead to volume reduction. The main areas of interest regarding high-pressure processing of food include: inactivation of microorganisms, modification of biopolymers, quality retention (especially in terms of flavour and colour, and changes in product functionality. Food components responsible for the nutritive value and sensory properties of food remain unaffected by high pressure. Based on the theoretical background of high-pressure processing and taking into account its advantages and limitations, this paper aims to show its possible application in food processing. The paper gives an outline of the special equipment used in highpressure processing. Typical high pressure equipment in which pressure can be generated either by direct or indirect compression are presented together with three major types of high pressure food processing: the conventional (batch system, semicontinuous and continuous systems. In addition to looking at this technology’s ability to inactivate microorganisms at room temperature, which makes it the ultimate alternative to thermal treatments, this paper also explores its application in dairy, meat, fruit and vegetable processing. Here presented are the effects of high-pressure treatment in milk and dairy processing on the inactivation of microorganisms and the modification of milk protein, which has a major impact on rennet coagulation and curd formation properties of treated milk. The possible application of this treatment in controlling cheese manufacture, ripening and safety is discussed. The opportunities

  3. Pressure ulcer classification: defining early skin damage.

    Science.gov (United States)

    Russell, Linda

    2002-09-01

    This article is the second of a two-part series. The first part (Russell, 2002) looked at various systems and pitfalls of pressure ulcer classification systems. This article focuses on the difficulties of defining early skin damage. Patients' quality of life suffers significantly with a pressure ulcer. The smell of the exudate may be an embarrassment to the patient. The pain and the distress the patient will experience will not easily be forgotten, i.e. the number of dressings required for a deep pressure ulcer, even after the pressure ulcer has healed, will be a memorable intrusion to the patient's daily routine. Early detection of pressure ulcers and timely intervention are essential in the management of patients with pressure ulcers. Controversy exists over the definition of the first three stages of pressure ulcers, but there is consensus on the definition of deep tissue damage. If the pressure ulcer is covered with black necrotic tissue it is difficult to establish depth of the tissue damage. Intact skin can cause problems, as a sacrum may be purple but intact. There is still considerable debate with regard to reactive hyperaemia, as the exact time parameters for persistent erythema to occur are unknown. Little is understood with regard to the exact pathophysiology of reactive hyperaemia and this area requires further investigation. Blistered skin and skin tone also cause confusion in grading of pressure ulcers. The problems associated with classification of pressure ulcers, using colour classification systems, are discussed and the implications for practice are considered. The confusion surrounding early classification of pressure ulcers is discussed and it is hoped that such confusion can be addressed by standardizing training using one national classification system. PMID:12362151

  4. High-Pressure Lightweight Thrusters

    Science.gov (United States)

    Holmes, Richard; McKechnie, Timothy; Shchetkovskiy, Anatoliy; Smirnov, Alexander

    2013-01-01

    Returning samples of Martian soil and rock to Earth is of great interest to scientists. There were numerous studies to evaluate Mars Sample Return (MSR) mission architectures, technology needs, development plans, and requirements. The largest propulsion risk element of the MSR mission is the Mars Ascent Vehicle (MAV). Along with the baseline solid-propellant vehicle, liquid propellants have been considered. Similar requirements apply to other lander ascent engines and reaction control systems. The performance of current state-ofthe- art liquid propellant engines can be significantly improved by increasing both combustion temperature and pressure. Pump-fed propulsion is suggested for a single-stage bipropellant MAV. Achieving a 90-percent stage propellant fraction is thought to be possible on a 100-kg scale, including sufficient thrust for lifting off Mars. To increase the performance of storable bipropellant rocket engines, a high-pressure, lightweight combustion chamber was designed. Iridium liner electrodeposition was investigated on complex-shaped thrust chamber mandrels. Dense, uniform iridium liners were produced on chamber and cylindrical mandrels. Carbon/carbon composite (C/C) structures were braided over iridium-lined mandrels and densified by chemical vapor infiltration. Niobium deposition was evaluated for forming a metallic attachment flange on the carbon/ carbon structure. The new thrust chamber was designed to exceed state-of-the-art performance, and was manufactured with an 83-percent weight savings. High-performance C/Cs possess a unique set of properties that make them desirable materials for high-temperature structures used in rocket propulsion components, hypersonic vehicles, and aircraft brakes. In particular, more attention is focused on 3D braided C/Cs due to their mesh-work structure. Research on the properties of C/Cs has shown that the strength of composites is strongly affected by the fiber-matrix interfacial bonding, and that weakening

  5. PRESSURE-IMPULSE DIAGRAM OF MULTI-LAYERED ALUMINUM FOAM PANELS UNDER BLAST PRESSURE

    Directory of Open Access Journals (Sweden)

    CHANG-SU SHIM

    2013-06-01

    Full Text Available Anti-terror engineering has increasing demand in construction industry, but basis of design (BOD is normally not clear for designers. Hardening of structures has limitations when design loads are not defined. Sacrificial foam claddings are one of the most efficient methods to protect blast pressure. Aluminum foam can have designed yield strength according to relative density and mitigate the blast pressure below a target transmitted pressure. In this paper, multi-layered aluminum foam panels were proposed to enhance the pressure mitigation by increasing effective range of blast pressure. Through explicit finite element analyses, the performance of blast pressure mitigation by the multi-layered foams was evaluated. Pressure-impulse diagrams for the foam panels were developed from extensive analyses. Combination of low and high strength foams showed better applicability in wider range of blast pressure.

  6. Hydraulic High Pressure Valve Controller Using the In-Situ Pressure Difference

    Science.gov (United States)

    Bao, Xiaoqi (Inventor); Sherrit, Stewart (Inventor); Badescu, Mircea (Inventor); Bar-Cohen, Yoseph (Inventor); Hall, Jeffery L. (Inventor)

    2016-01-01

    A hydraulic valve controller that uses an existing pressure differential as some or all of the power source for valve operation. In a high pressure environment, such as downhole in an oil or gas well, the pressure differential between the inside of a pipe and the outside of the pipe may be adequately large to drive a linear slide valve. The valve is operated hydraulically by a piston in a bore. When a higher pressure is applied to one end of the bore and a lower pressure to the other end, the piston moves in response to the pressure differential and drives a valve attached to it. If the pressure differential is too small to drive the piston at a sufficiently high speed, a pump is provided to generate a larger pressure differential to be applied. The apparatus is conveniently constructed using multiport valves, which can be rotary valves.

  7. Noise Evaluation Technique Based on Surface Pressure

    DEFF Research Database (Denmark)

    Fischer, Andreas

    2012-01-01

    In this chapter the relevant theory for the understanding of TE noise modeling is collected. It contains the acoustic formulations of [31] and [57]. Both give a relation for the far field sound pressure in dependence of the frequency wave number spectral density of the pressure on the airfoil...

  8. Pressure diffusion waves in porous media

    Energy Technology Data Exchange (ETDEWEB)

    Silin, Dmitry; Korneev, Valeri; Goloshubin, Gennady

    2003-04-08

    Pressure diffusion wave in porous rocks are under consideration. The pressure diffusion mechanism can provide an explanation of the high attenuation of low-frequency signals in fluid-saturated rocks. Both single and dual porosity models are considered. In either case, the attenuation coefficient is a function of the frequency.

  9. Intraoral Pressure in Ethnic Wind Instruments

    CERN Document Server

    Goss, Clinton F

    2013-01-01

    High intraoral pressure generated when playing some wind instruments has been linked to a variety of health issues. Prior research has focused on Western classical instruments, but no work has been published on ethnic wind instruments. This study measured intraoral pressure when playing six classes of ethnic wind instruments (N = 149): Native American flutes (n = 71) and smaller samples of ethnic duct flutes, reed instruments, reedpipes, overtone whistles, and overtone flutes. Results are presented in the context of a survey of prior studies, providing a composite view of the intraoral pressure requirements of a broad range of wind instruments. Mean intraoral pressure was 8.37 mBar across all ethnic wind instruments and 5.21 +/- 2.16 mBar for Native American flutes. The range of pressure in Native American flutes closely matches pressure reported in other studies for normal speech, and the maximum intraoral pressure, 20.55 mBar, is below the highest subglottal pressure reported in other studies during singing...

  10. [Demographic pressure: a factor in political instability].

    Science.gov (United States)

    Tallon, F

    1991-01-01

    A review of population trends in Rwanda is presented. They include the growing pressure on available land and resources due to an increase in the numbers of people and cattle. The author finds that this pressure, combined with ethnic tensions, has created an explosive political situation. He concludes that political stability is possible only if a vigorous population policy is implemented.

  11. Development of Zirconium alloys (for pressure tubes)

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Young Suk; Kwon, Sang Chul; Choo, Ki Nam; Jung, Chung Hwan; Yim, Kyong Soo; Kim, Sung Soo; Baek, Jong Hyuk; Jeong, Yong Hwan; Kim, Kyong Ho; Cho, Hae Dong [Korea Atomic Energy Research Inst., Daeduk (Korea, Republic of); Hwang, S. K.; Kim, M. H. [Inha Univ., Incheon (Korea, Republic of); Kwon, S. I [Korea Univ., Seoul (Korea, Republic of); Kim, I. S. [Korea Advanced Inst. of Science and Technology, Taejon (Korea, Republic of)

    1997-09-01

    The objective of this research is to set up the basic technologies for the evaluation of pressure tube integrity and to develop improved zirconium alloys to prevent pressure tube failures due to DHC and hydride blister caused by excessive creep-down of pressure tubes. The experimental procedure and facilities for characterization of pressure tubes were developed. The basic research related to a better understanding of the in-reactor performances of pressure tubes leads to noticeable findings for the first time : the microstructural effect on corrosion and hydrogen pick-up behavior of Zr-2.5Nb pressure tubes, texture effect on strength and DHC resistance and enhanced recrystallization by Fe in zirconium alloys and etc. Analytical methodology for the assessment of pressure tubes with surface flaws was set up. A joint research is being under way with AECL to determine the fracture toughness of O-8 at the EOL (End of Life) that had been quadruple melted and was taken out of the Wolsung Unit-1 after 10 year operation. In addition, pressure tube with texture controlled is being made along with VNINM in Russia as a joint project between KAERI and Russia. Finally, we succeeded in developing 4 different kinds of zirconium alloys with better corrosion resistance, low hydrogen pickup fraction and higher creep strength. (author). 121 refs., 65 tabs., 260 figs

  12. Pressure sensitive adhesives from renewable resources

    OpenAIRE

    Maaßen, Wiebke

    2015-01-01

    Pressure-sensitive adhesives (PSAs) represent an important segment of the adhesives market. In this work, novel insights into the adhesive performance of bio-based pressure sensitive adhesives are presented. Three different homopolymers based on fatty acids derived from native vegetable oils as renewable feedstock were characterized in terms of their mechanical and adhesive properties.

  13. Pressurized SOFC systems for stationary applications

    OpenAIRE

    Leucht, Florian; Seidler, Stephanie; Henke, Moritz; Bessler, Wolfgang G.; Kallo, Josef; Friedrich, K. Andreas

    2009-01-01

    Solid oxide fuel cell (SOFC) systems show very high electrical efficiencies even at small sizes. DLR applies a multidisciplinary and multiscale approach to designing and optimizing pressurized SOFC systems for hybrid power plants. A large Simulink model library was developed featuring balance-of-plant components as well as fuel cell models. Recently a pressurized cell test rig was taken into operation.

  14. An Atmospheric Pressure Ping-Pong "Ballometer"

    Science.gov (United States)

    Kazachkov, Alexander; Kryuchkov, Dmitriy; Willis, Courtney; Moore, John C.

    2006-01-01

    Classroom experiments on atmospheric pressure focus largely on demonstrating its existence, often in a most impressive way. A series of amusing physics demonstrations is widely known and practiced by educators teaching the topic. However, measuring the value of atmospheric pressure(P[subscript atm]) is generally done in a rather mundane way,…

  15. STUDY ON THE PRESSURE IN PLASMA ARC

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    The axial pressure in plasma arc is measured under different conditions. The effects of the parameters, such as welding current, plasma gas flow rate, electrode setback and arc length, on the pressure in plasma arc are investigated and quantitative analyzed to explain the relationship between the quality of weld and the matching of parameters in plasma arc welding process.

  16. Enhanced Strength via crack friction and Pressure

    Science.gov (United States)

    Wiegand, Donald; Ellis, Kevin; Leppard, Claire

    2011-03-01

    The effect of pressure on the mechanical response of particulate polymer composites is being studied. Between about 0.1 and 7 MPa for one composite the results indicate that slow crack growth is the dominant failure mode. With continuously creasing strain at low pressures the stress initially increases to a maximum, the compressive strength, then decreases indicating work softening and them becomes approximately constant at a plateau value. Both the compressive strength and the plateau stress increases linearly with pressure but the plateau stress increases with a steeper slope such that at higher pressures work softening is not observed. The results are analyzed in terms of shear cracks with friction between the crack surfaces. The model predicts a threshold stress for crack growth which increases linearly with pressure and further predicts that the compressive strength increases linearly with pressure as observed and with the same slope as the threshold stress. These results clearly indicate that the pressure dependence of the compressive strength is due to the pressure dependence of the threshold stress for crack growth. The changes in the plateau region can also be attributed to frictional effects. Supported by AWE Aldermaston.

  17. Brief Introduction to Digital Acupoint Pressure Therapy

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    @@ The Concept of Digital Acupoint Pressure Therapy The digital acupoint pressure therapy means that according to different diseases and the illness condition, the physician strikes, presses or taps the acupoints with hands on the patient's body surface to promote the circulation of qi and blood, thus making dysfunctions of certain organs or the affected areas return to normal.

  18. Total Site Heat Integration Considering Pressure Drops

    Directory of Open Access Journals (Sweden)

    Kew Hong Chew

    2015-02-01

    Full Text Available Pressure drop is an important consideration in Total Site Heat Integration (TSHI. This is due to the typically large distances between the different plants and the flow across plant elevations and equipment, including heat exchangers. Failure to consider pressure drop during utility targeting and heat exchanger network (HEN synthesis may, at best, lead to optimistic energy targets, and at worst, an inoperable system if the pumps or compressors cannot overcome the actual pressure drop. Most studies have addressed the pressure drop factor in terms of pumping cost, forbidden matches or allowable pressure drop constraints in the optimisation of HEN. This study looks at the implication of pressure drop in the context of a Total Site. The graphical Pinch-based TSHI methodology is extended to consider the pressure drop factor during the minimum energy requirement (MER targeting stage. The improved methodology provides a more realistic estimation of the MER targets and valuable insights for the implementation of the TSHI design. In the case study, when pressure drop in the steam distribution networks is considered, the heating and cooling duties increase by 14.5% and 4.5%.

  19. Pore Pressure Measurements Inside Rubble Mound Breakwaters

    DEFF Research Database (Denmark)

    Helgason, Einar; Burcharth, H. F.; Grüne, Joachim

    2004-01-01

    The present paper presents pore pressure measurements from large scale model tests performed at the Large Wave Channel, Hannover, Germany and small scale model test performed at the Hydraulic & Coastal Engineering Laboratory, Aalborg University, Denmark. Information on pore pressure attenuation a...

  20. Identifying the weights in exchange market pressure

    NARCIS (Netherlands)

    F. Klaassen

    2012-01-01

    Exchange market pressure (EMP) measures the pressure on a currency to depreciate, and it is particularly relevant in crisis periods. EMP adds to the actual depreciation a weighted combination of policy instruments used to ward off depreciation, such as interest rates and foreign exchange interventio

  1. Pressure ulcer risk in hip fracture patients

    NARCIS (Netherlands)

    Houwing, RH; Rozendaal, M; Wouters-Wesseling, W; Buskens, E; Keller, P; Haalboom, JRE

    2004-01-01

    Hip fracture patients have a high risk of pressure ulcers (PU). We followed 121 hip fracture patients for the development of pressure ulcers and evaluated a risk assessment tool for sensitivity and specificity. More than half of the patients presented with PU, mostly stage I. Risk factors for PU wer

  2. Structural studies of amorphous Se under pressure

    OpenAIRE

    Tanaka, Keiji

    1990-01-01

    X-ray-diffraction patterns, macroscopic compressibility, and crystallization in amorphous Se subject to pressure have been investigated. The material exhibits pressure-induced structural modifications in the glassy state and a phase transformation to the hexagonal phase at 120±20 kbar. The observations are discussed on the basis of microscopic and thermodynamic models.

  3. Comparing maximum pressures in internal combustion engines

    Science.gov (United States)

    Sparrow, Stanwood W; Lee, Stephen M

    1922-01-01

    Thin metal diaphragms form a satisfactory means for comparing maximum pressures in internal combustion engines. The diaphragm is clamped between two metal washers in a spark plug shell and its thickness is chosen such that, when subjected to explosion pressure, the exposed portion will be sheared from the rim in a short time.

  4. Energy harvesting from hydraulic pressure fluctuations

    Science.gov (United States)

    Cunefare, K. A.; Skow, E. A.; Erturk, A.; Savor, J.; Verma, N.; Cacan, M. R.

    2013-02-01

    State-of-the-art hydraulic hose and piping systems employ integral sensor nodes for structural health monitoring to avoid catastrophic failures. Energy harvesting in hydraulic systems could enable self-powered wireless sensor nodes for applications such as energy-autonomous structural health monitoring and prognosis. Hydraulic systems inherently have a high energy intensity associated with the mean pressure and flow. Accompanying the mean pressure is the dynamic pressure ripple, which is caused by the action of pumps and actuators. Pressure ripple is a deterministic source with a periodic time-domain behavior conducive to energy harvesting. An energy harvester prototype was designed for generating low-power electricity from pressure ripples. The prototype employed an axially-poled off-the-shelf piezoelectric stack. A housing isolated the stack from the hydraulic fluid while maintaining a mechanical coupling allowing for dynamic-pressure-induced deflection of the stack. The prototype exhibited an off-resonance energy harvesting problem since the fundamental resonance of the piezoelectric stack was much higher than the frequency content of the pressure ripple. The prototype was designed to provide a suitable power output for powering sensors with a maximum output of 1.2 mW. This work also presents electromechanical model simulations and experimental characterization of the piezoelectric power output from the pressure ripple in terms of the force transmitted into the harvester.

  5. What is Pressure? Evidence for Social Pressure as a Type of Regulatory Focus

    OpenAIRE

    Darrell A. Worthy; Markman, Arthur B.; Maddox, W. Todd

    2009-01-01

    Previous research suggests that pressure leads to choking when learning to classify items based on an explicit rule, but leads to excelling when learning to classify based on an implicit strategy. In this paper we relate social pressure to regulatory focus theory. We propose that the effects of pressure on performance arise because pressure induces a prevention focus that interacts with the more local reward structure of the task. To test this hypothesis, we repeat this previous research with...

  6. Relationship between Vehicle Manufacturers Recommended Tyre Pressure and Tyre Pressure Used by Vehicle Owners

    OpenAIRE

    Timothy Alhassan; Prince Y. Andoh; Prince Owusu-Ansah; Justice Alex Frimpong

    2014-01-01

    This paper studies the relationship between the tyre pressures used by drivers and the vehicle manufacturers recommended tyre pressure. First of all, a survey of vehicles on Kwame Nkrumah University of Science and Technology (KNUST) campus was done to ascertain how tyre pressures of these vehicles deviate from the vehicle manufacturers recommended tyre pressures. Then the survey was extended to other four places namely, Kumasi Polytechnic campus, Asafo, Roman Hill and Kejetia bus depots. The ...

  7. DEEP COLLIERY PRESSURE BUMPS AND ITS PREVENTIONS UNDER THE ACTION OF ABUTMENT PRESSURE

    Institute of Scientific and Technical Information of China (English)

    杜计平; 张先尘; 田昌栋; 闫培华

    1999-01-01

    Based on field measurement, the relations was introduced between mining depth and the peak value places of abutment pressures in long wall face of the deep colliery with caving method to handle goaf, and the reasons and kinds of pressure bumps are analysed under the action of the moving and constant abutment pressures formed by the method of long wall caving or room and pillar mining, and the relative precautions were put forward to prevent the pressure bumps in deep mining.

  8. Ambulatory Blood Pressure Monitoring and Circadian Rhythm of Blood Pressure in Diabetes Mellitus

    OpenAIRE

    Elena Matteucci; Ottavio Giampietro

    2013-01-01

    Systolic and diastolic blood pressures display a circadian rhythmicity that can be assessed by 24-hour ambulatory blood pressure monitoring and analysed using the cosinor procedure. Altered characteristics to the circadian rhythm of blood pressure, which may result in adverse health outcomes, have been observed in both prediabetes and diabetes. We have investigated the circadian variability of blood pressure in patients with type 1 and type 2 diabetes. Chronobiologically interpreted ambulator...

  9. Evaluation of spatial pressure distribution during ice-structure interaction using pressure indicating film

    OpenAIRE

    Kim Hyunwook; Ulan-Kvitberg Christopher; Daley Claude

    2014-01-01

    Understanding of ‘spatial’ pressure distribution is required to determine design loads on local structures, such as plating and framing. However, obtaining a practical ‘spatial’ pressure distribution is a hard task due to the sensitivity of the data acquisition frequency and resolution. High-resolution Pessure-Idicating Flm (PIF) was applied to obtain pressure distribution and pressure magnitude using stepped crushing method. Different types of PIF were stacked at each test to creating a pres...

  10. Reduction of System Inherent Pressure Losses at Pressure Compensators of Hydraulic Load Sensing Systems

    OpenAIRE

    Siebert, Jan; Geimer, Marcus [Hrsg.

    2016-01-01

    In spite of their high technical maturity, load sensing systems (LS) have system-inherent energy losses that are largely due to the operation of parallel actuators with different loads at the same pressure level. Hereby, the pressure compensators of the system are crucial. So far, excessive hydraulic energy has been throttled at these compensators and been discharged as heat via the oil. The research project “Reduction of System Inherent Pressure Losses at Pressure Compensators of Hydraulic L...

  11. DIASTOLIC BLOOD PRESSURE OR ACTUALLY IT IS BASELINE SYSTOLIC BLOOD PRESSURE?

    OpenAIRE

    R.Vinodh Rajkumar

    2015-01-01

    Blood pressure measuring represents a routine investigation in general medicine. Nokolai Korotkoff was only 31 years old when he made a short presentation to the Scientific Meeting of the Military Hospital of the Academy on 5 November 1905 concerning an easy non-invasive method of blood pressure (BP) measurement, entitled ‘Concerning the problems of the methods of blood pressure measurement’. If the pressure in the cuff is relieved, blood starts coming through the compressed arterial segment...

  12. The Iceland–Lofotes pressure difference: different states of the North Atlantic low-pressure zone

    OpenAIRE

    Jahnke-Bornemann, Annika; Brümmer, Burghard

    2009-01-01

    The extended North Atlantic low-pressure zone exhibits two pressure minima in the long-term winter mean: the primary one west of Iceland and the secondary one near Norwegian Lofotes Islands. Based on the ERA-40 data set and on wintertime monthly sea level pressure (SLP) anomalies at both places, the states of co- and antivariability are investigated. The covariability represents states of a strongly or weakly developed North Atlantic low-pressure zone. The difference between these two states ...

  13. High precision pressure measurement with a funnel

    Energy Technology Data Exchange (ETDEWEB)

    Lopez-Arias, T; Gratton, L M; Oss, S [Physics Department, University of Trento, 38100 Povo, Trento (Italy)], E-mail: teresa@science.unitn.it, E-mail: gratton@science.unitn.it, E-mail: stefano.oss@unitn.it

    2008-11-12

    A simple experimental device for high precision differential pressure measurements is presented. Its working mechanism recalls that of a hydraulic press, where pressure is supplied by insufflating air under a funnel. As an application, we measure air pressure inside a soap bubble. The soap bubble is inflated and connected to a funnel which is placed, upside down, in a container filled with distilled water, placed on a scale. Our method provides a theoretical precision for the pressure measurement of the order of 0.01 Pa. Beyond this, the advantage of this method relies on the simplicity of the materials used and on the opportunity to discuss, at an undergraduate level, basic concepts regarding all those phenomena in which low or very low differential pressures are relevant.

  14. High-pressure phases of alumina

    Science.gov (United States)

    Lyle, Matthew; Pickard, Chris; Needs, Richard

    2014-03-01

    Alumina (Al2O3) has been widely used as a pressure standard in static diamond anvil cell experiments and is a major chemical component of the Earth. So a detailed knowledge of its high-pressure stability is of great importance in both materials science and deep Earth science. A phase transition is known to occur at roughly 80-100 GPa between corundum and the Rh2O3 (II) structure. A second phase transition to the CaIrO3 structure occurs at even higher pressures. Here we present a computational structure search to reveal three additional structures which are competitive at these pressures but hitherto unknown to be stable in high-pressure alumina.

  15. Effects of Ambient Pressure on Bubble Characteristics

    Institute of Scientific and Technical Information of China (English)

    卢新培; 刘明海; 江中和; 潘垣

    2002-01-01

    The effects of the ambient pressure Pambient on the bubble characteristics of pulsed discharge in water are investigated. The simulation results show that, when Pambient increases from 1 atm to 100 atm, the bubble radius R decreases from 4cma to 7mm, and its pulsation period decreases frown 8ms to 0.2ms. The results also show that the peak pressure of the first shock wave is independent of Pambient, but the peak pressure of the second shock wave caused by the bubble re-expansion decreases when Pambient increases. On the other hand, the larger the ambient pressure, the larger the peak pressure of the plasma in the bubble, while the plasma temperature is independent of Pambient.

  16. Cagelike diamondoid nitrogen at high pressures.

    Science.gov (United States)

    Wang, Xiaoli; Wang, Yanchao; Miao, Maosheng; Zhong, Xin; Lv, Jian; Cui, Tian; Li, Jianfu; Chen, Li; Pickard, Chris J; Ma, Yanming

    2012-10-26

    Under high pressure, triply bonded molecular nitrogen dissociates into singly bonded polymeric nitrogen, a potential high-energy-density material. The discovery of stable high-pressure forms of polymeric nitrogen is of great interest. We report the striking stabilization of cagelike diamondoid nitrogen at high pressures predicted by first-principles structural searches. The diamondoid structure of polymeric nitrogen has not been seen in any other elements, and it adopts a highly symmetric body-centered cubic structure with lattice sites occupied by diamondoids, each of which consists of ten nitrogen atoms, forming a N(10) tetracyclic cage. Diamondoid nitrogen possesses a wide energy gap and is energetically most stable among all known polymeric structures above 263 GPa, a pressure that is accessible to a high-pressure experiment. Our findings represent a significant step toward the understanding of the behavior of solid nitrogen at extreme conditions. PMID:23215200

  17. PRESSURE FLUCTUATIONS BENEATH SPATIAL HYDRAULIC JUMPS

    Institute of Scientific and Technical Information of China (English)

    YAN Zhong-min; ZHOU Chun-tian; LU Shi-qiang

    2006-01-01

    This article deals with statistical analysis of pressure fluctuations at the bottom of spatial hydraulic jumps with abrupt lateral expansions. The effects of the channel expansion ratio and inflow condition on the power spectral and dominant frequency were examined. Pressure data were recorded for different Froude numbers ranging from 3.52 to 6.86 and channel expansion ratios ranging from 1.5 to 3.0. A sampling frequency of 100 Hz was selected. The measurements were conducted in the bed of a glass-walled laboratory flume by means of pressure transducers and data acquisition systems. Power spectra as well as dominant frequency and some other statistical characteristics of fluctuating pressure beneath hydraulic jumps were obtained. Test results were compared with those of classical jump, which indicates that the peak frequencies and intensity coefficients of pressure fluctuations are higher than those of the corresponding classical jumps.

  18. Wellbore pressure response in naturally fractured reservoirs

    Energy Technology Data Exchange (ETDEWEB)

    Reynolds, A.C. Jr.; Chang, W.; Raghavan, R.

    1983-01-01

    Recently a new flow regime has been identified for pressure drawdown or buildup data obtained from a well producing a naturally fractured reservoir. During the time period corresponding to this new flow regime, a semilog plot of pressure vs. time exhibits a semilog straight line with slope equal to m/2, where m is the slope of both the early and late time semilog straight lines predicted by the Warren and Root model. The identification of this intermediate time semilog straight line means that pressure data may exhibit as many as 3 semilog straight lines. A virtually complete analysis of well test pressure data is possible when the data exhibits 2 or more of the 3 possible straight lines. This work presents type curves which can be used to obtain a virtually complete analysis of pressure data when only one of the 3 semilog straight lines is reflected by the data. 13 references.

  19. Liquefaction of Sand under Low Confining Pressure

    Institute of Scientific and Technical Information of China (English)

    YANG Shaoli; Rolf Sandven; Lars Grande

    2003-01-01

    Undrained behaviour of sand under low cell pressure was studied in static and cyclic triaxial tests. It was found that very loose sand liquefies under static loading with the relative density being a key parameter for the undrained behaviour of sand. In cyclic triaxial tests, pore water pressures built up during the cyclic loading and exceeded the confining cell pressure. This process was accompanied by a large sudden increase in axial deformation. The necessary number of cycles to obtain liquefaction was related to the confining cell pressure, the amplitude of cyclic loading and the relative density of sand.In addition, the patterns of pore water pressure response are different from those of sand samples with different relative densities. The test results are very useful for expounding scour mechanism around coastal structures since they relate to the low stress behaviour of the sand.

  20. Blast Quantification Using Hopkinson Pressure Bars.

    Science.gov (United States)

    Clarke, Samuel D; Fay, Stephen D; Rigby, Samuel E; Tyas, Andrew; Warren, James A; Reay, Jonathan J; Fuller, Benjamin J; Gant, Matthew T A; Elgy, Ian D

    2016-07-05

    Near-field blast load measurement presents an issue to many sensor types as they must endure very aggressive environments and be able to measure pressures up to many hundreds of megapascals. In this respect the simplicity of the Hopkinson pressure bar has a major advantage in that while the measurement end of the Hopkinson bar can endure and be exposed to harsh conditions, the strain gauge mounted to the bar can be affixed some distance away. This allows protective housings to be utilized which protect the strain gauge but do not interfere with the measurement acquisition. The use of an array of pressure bars allows the pressure-time histories at discrete known points to be measured. This article also describes the interpolation routine used to derive pressure-time histories at un-instrumented locations on the plane of interest. Currently the technique has been used to measure loading from high explosives in free air and buried shallowly in various soils.

  1. Selective pressures on genomes in molecular evolution

    CERN Document Server

    Ofria, C A; Collier, T C; Ofria, Charles; Adami, Christoph; Collier, Travis C.

    2003-01-01

    We describe the evolution of macromolecules as an information transmission process and apply tools from Shannon information theory to it. This allows us to isolate three independent, competing selective pressures that we term compression, transmission, and neutrality selection. The first two affect genome length: the pressure to conserve resources by compressing the code, and the pressure to acquire additional information that improves the channel, increasing the rate of information transmission into each offspring. Noisy transmission channels (replication with mutations) gives rise to a third pressure that acts on the actual encoding of information; it maximizes the fraction of mutations that are neutral with respect to the phenotype. This neutrality selection has important implications for the evolution of evolvability. We demonstrate each selective pressure in experiments with digital organisms.

  2. Stellar feedback by radiation pressure and photoionization

    CERN Document Server

    Sales, Laura V; Springel, Volker; Petkova, Margarita

    2013-01-01

    The relative impact of radiation pressure and photoionization feedback from young stars on surrounding gas is studied with hydrodynamic radiative transfer (RT) simulations. The calculations focus on the single-scattering (direct radiation pressure) and optically thick regime, and adopt a moment-based RT-method implemented in the moving-mesh code AREPO. The source luminosity, gas density profile and initial temperature are varied. At typical temperatures and densities of molecular clouds, radiation pressure drives velocities of order ~20 km/s over 1-5 Myr; enough to unbind the smaller clouds. However, these estimates ignore the effects of photoionization that naturally occur concurrently. When radiation pressure and photoionization act together, the latter is substantially more efficient, inducing velocities comparable to the sound speed of the hot ionized medium (10-15 km/s) on timescales far shorter than required for accumulating similar momentum with radiation pressure. This mismatch allows photoionization ...

  3. Infrared Spectra of High Pressure Carbon Monoxide

    Energy Technology Data Exchange (ETDEWEB)

    Evans, W J; Lipp, M J; Lorenzana, H E

    2001-09-21

    We report infrared (IR) spectroscopic measurements of carbon monoxide (CO) at high pressures. Although CO is one of the simplest heteronuclear diatomic molecules, it displays surprisingly complex behavior at high pressures and has been the subject of several studies [1-5]. IR spectroscopic studies of high pressures phases of CO provide data complementing results from previous studies and elucidating the nature of these phases. Though a well-known and widely utilized diagnostic of molecular systems, IR spectroscopy presents several experimental challenges to high pressure diamond anvil cell research. We present measurements of the IR absorption bands of CO at high pressures and experimentally illustrate the crucial importance of accurate normalization of IR spectra specially within regions of strong absorptions in diamond.

  4. Using Dalton's Law of Partial Pressures to Determine the Vapor Pressure of a Volatile Liquid

    Science.gov (United States)

    Hilgeman, Fred R.; Bertrand, Gary; Wilson, Brent

    2007-01-01

    This experiment, designed for a general chemistry laboratory, illustrates the use of Dalton's law of partial pressures to determine the vapor pressure of a volatile liquid. A predetermined volume of air is injected into a calibrated tube filled with a liquid whose vapor pressure is to be measured. The volume of the liquid displaced is greater than…

  5. 49 CFR 192.621 - Maximum allowable operating pressure: High-pressure distribution systems.

    Science.gov (United States)

    2010-10-01

    ...) No person may operate a segment of a high pressure distribution system at a pressure that exceeds the... segment of a distribution system otherwise designed to operate at over 60 p.s.i. (414 kPa) gage, unless..., particularly known corrosion and the actual operating pressures. (b) No person may operate a segment...

  6. Interaction between intra-abdominal pressure and positive-end expiratory pressure

    Directory of Open Access Journals (Sweden)

    Jamili Anbar Torquato

    2009-02-01

    Full Text Available OBJECTIVE: The aim of this study was to quantify the interaction between increased intra-abdominal pressure and Positive-End Expiratory Pressure. METHODS: In 30 mechanically ventilated ICU patients with a fixed tidal volume, respiratory system plateau and abdominal pressure were measured at a Positive-End Expiratory Pressure level of zero and 10 cm H2O. The measurements were repeated after placing a 5 kg weight on the patients' belly. RESULTS: After the addition of 5 kg to the patients' belly at zero Positive-End Expiratory Pressure, both intra-abdominal pressure (p<0.001 and plateau pressures (p=0.005 increased significantly. Increasing the Positive-End Expiratory Pressure levels from zero to 10 cm H2O without weight on the belly did not result in any increase in intra-abdominal pressure (p=0.165. However, plateau pressures increased significantly (p< 0.001. Increasing Positive-End Expiratory Pressure from zero to 10 cm H2O and adding 5 kg to the belly increased intra-abdominal pressure from 8.7 to 16.8 (p<0.001 and plateau pressure from 18.26 to 27.2 (p<0.001. Maintaining Positive-End Expiratory Pressure at 10 cm H2O and placing 5 kg on the belly increased intra-abdominal pressure from 12.3 +/- 1.7 to 16.8 +/- 1.7 (p<0.001 but did not increase plateau pressure (26.6+/-1.2 to 27.2 +/-1.1 -p=0.83. CONCLUSIONS: The addition of a 5kg weight onto the abdomen significantly increased both IAP and the airway plateau pressure, confirming that intra-abdominal hypertension elevates the plateau pressure. However, plateau pressure alone cannot be considered a good indicator for the detection of elevated intra-abdominal pressure in patients under mechanical ventilation using PEEP. In these patients, the intra-abdominal pressure must also be measured.

  7. Modeling, Parameters Identification, and Control of High Pressure Fuel Cell Back-Pressure Valve

    Directory of Open Access Journals (Sweden)

    Fengxiang Chen

    2014-01-01

    Full Text Available The reactant pressure is crucial to the efficiency and lifespan of a high pressure PEMFC engine. This paper analyses a regulated back-pressure valve (BPV for the cathode outlet flow in a high pressure PEMFC engine, which can achieve precisely pressure control. The modeling, parameters identification, and nonlinear controller design of a BPV system are considered. The identified parameters are used in designing active disturbance rejection controller (ADRC. Simulations and extensive experiments are conducted with the xPC Target and show that the proposed controller can not only achieve good dynamic and static performance but also have strong robustness against parameters’ disturbance and external disturbance.

  8. EIT-Based Fabric Pressure Sensing

    Directory of Open Access Journals (Sweden)

    A. Yao

    2013-01-01

    Full Text Available This paper presents EIT-based fabric sensors that aim to provide a pressure mapping using the current carrying and voltage sensing electrodes attached to the boundary of the fabric patch. Pressure-induced shape change over the sensor area makes a change in the conductivity distribution which can be conveyed to the change of boundary current-voltage data. This boundary data is obtained through electrode measurements in EIT system. The corresponding inverse problem is to reconstruct the pressure and deformation map from the relationship between the applied current and the measured voltage on the fabric boundary. Taking advantage of EIT in providing dynamical images of conductivity changes due to pressure induced shape change, the pressure map can be estimated. In this paper, the EIT-based fabric sensor was presented for circular and rectangular sensor geometry. A stretch sensitive fabric was used in circular sensor with 16 electrodes and a pressure sensitive fabric was used in a rectangular sensor with 32 electrodes. A preliminary human test was carried out with the rectangular sensor for foot pressure mapping showing promising results.

  9. Particle pressures in fluidized beds. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Campbell, C.S.; Rahman, K.; Jin, C.

    1996-09-01

    This project studies the particle pressure, which may be thought of as the force exerted by the particulate phase of a multiphase mixture, independently of that exerted by other phases. The project is divided into two parts, one concerning gas and the other liquid fluidized beds. Previous work on gas fluidized beds had suggested that the particle pressures are generated by bubbling action. Thus, for these gas fluidized bed studies, the particle pressure is measured around single bubbles generated in 2-D fluidized beds, using special probes developed especially for this purpose. Liquid beds are immune from bubbling and the particle pressures proved too small to measure directly. However, the major interest in particle pressures in liquid beds lies in their stabilizing effect that arises from the effective elasticity (the derivative of the particle pressure with respect to the void fraction), they impart to the bed. So rather than directly measure the particle pressure, the authors inferred the values of the elasticity from measurements of instability growth in liquid beds; the inference was made by first developing a generic stability model (one with all the normally modeled coefficients left undetermined) and then working backwards to determine the unknown coefficients, including the elasticity.

  10. Initiation Pressure Thresholds from Three Sources

    Energy Technology Data Exchange (ETDEWEB)

    Souers, P C; Vitello, P

    2007-02-28

    Pressure thresholds are minimum pressures needed to start explosive initiation that ends in detonation. We obtain pressure thresholds from three sources. Run-to-detonation times are the poorest source but the fitting of a function gives rough results. Flyer-induced initiation gives the best results because the initial conditions are the best known. However, very thick flyers are needed to give the lowest, asymptotic pressure thresholds used in modern models and this kind of data is rarely available. Gap test data is in much larger supply but the various test sizes and materials are confusing. We find that explosive pressures are almost the same if the distance in the gap test spacers are in units of donor explosive radius. Calculated half-width time pulses in the spacers may be used to create a pressure-time curve similar to that of the flyers. The very-large Eglin gap tests give asymptotic thresholds comparable to extrapolated flyer results. The three sources are assembled into a much-expanded set of near-asymptotic pressure thresholds. These thresholds vary greatly with density: for TATB/LX-17/PBX 9502, we find values of 4.9 and 8.7 GPa at 1.80 and 1.90 g/cm{sup 3}, respectively.

  11. Assessment of fiber optic pressure sensors

    International Nuclear Information System (INIS)

    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

  12. Swim Pressure: Stress Generation in Active Matter

    Science.gov (United States)

    Takatori, S. C.; Yan, W.; Brady, J. F.

    2014-07-01

    We discover a new contribution to the pressure (or stress) exerted by a suspension of self-propelled bodies. Through their self-motion, all active matter systems generate a unique swim pressure that is entirely athermal in origin. The origin of the swim pressure is based upon the notion that an active body would swim away in space unless confined by boundaries—this confinement pressure is precisely the swim pressure. Here we give the micromechanical basis for the swim stress and use this new perspective to study self-assembly and phase separation in active soft matter. The swim pressure gives rise to a nonequilibrium equation of state for active matter with pressure-volume phase diagrams that resemble a van der Waals loop from equilibrium gas-liquid coexistence. Theoretical predictions are corroborated by Brownian dynamics simulations. Our new swim stress perspective can help analyze and exploit a wide class of active soft matter, from swimming bacteria to catalytic nanobots to molecular motors that activate the cellular cytoskeleton.

  13. Monitoring cerebrovascular pressure reactivity with rheoencephalography

    Science.gov (United States)

    Brady, K. M.; Mytar, J. O.; Kibler, K. K.; Easley, R. B.; Koehler, R. C.; Czosnyka, M.; Smielewski, P.; Zweifel, C.; Bodo, M.; Pearce, F. J.; Armonda, R. A.

    2010-04-01

    Determining optimal perfusion pressure for patients with traumatic brain injury can be accomplished by monitoring the pressure reactivity index, or PRx, which requires an intracranial pressure monitor. We hypothesized that pressure reactivity could be quantified using a rheoencephalography index, or REGx. We measured the REGx and PRx as repetitive, low-frequency linear correlation between arterial blood pressure and intracranial pressure (PRx) or arterial blood pressure and REG pulse amplitude (REGx) in a piglet model of progressive hypotension. We compared the PRx and REGx against a gold standard determination of the lower limit of autoregulation using laser-Doppler measurements of cortical red cell flux. The PRx produced an accurate metric of vascular reactivity in this cohort, with area under the receiver-operator characteristic curves of 0.91. REGx was moderately correlated to the PRx, (Spearman r = 0.63, p < 0.0001; Bland-Altman bias-0.13). The area under the receiver-operator curve for the REGx was 0.86. Disagreement occurred at extremes of hypotension.

  14. Differential pressures on building walls during tornados

    International Nuclear Information System (INIS)

    In the United States, containment structures and some auxiliary structures (control building, auxiliary building, spent fuel building, etc.) in nuclear power plants are required to be designed to withstand the effects of the design basis tornado. In addition to velocity pressures and missile impact a tornado also gives rise to a rapid change in atmospheric pressure, which can, in cases of closed or partially vented structures, produce direct differential pressure loading. In this paper a digital computer program is described which applies a tornado-induced, time-dependent atmospheric pressure change to a building and calculates the differential pressure histories across the interior and exterior walls of the building. Laws for quasi-steady, one-dimensional motion of an ideal compressible gas are used to calculate the pressures due to the flow of air through ports, doors and windows in the building. Numerical examples show that for each assumed atmospheric pressure change history a vent area to compartment volume ratio may be specified as the criterion for a building to be considered fully vented. (orig.)

  15. Differential pressures on building walls during tornadoes

    International Nuclear Information System (INIS)

    In the United States, containment structures and some auxiliary structures (control buildings, auxiliary buildings, spent fuel buildings, etc.) in nuclear power plants are required to be designed to withstand the effects of the design basis tornado. In addition to velocity pressures and missile impact a tornado also causes a rapid change in atmospheric pressure, which can, in cases of closed or partially vented structures, produce direct differential pressure loading. In this paper a digital computer program is described which applies a tornado-induced, time-dependent atmospheric pressure change to a building and calculates the differential pressure histories across the interior and exterior walls of the building. Laws for quasi-steady, one-dimensional motion of an ideal compressible gas are used to calculate the pressures due to the flow of air through ports, doors and windows in the building. Numerical examples show that for each assumed atmospheric pressure change history a vent area to compartment volume ratio may be specified as the criterion for a building to be considered fully vented. (Auth.)

  16. Swim pressure: stress generation in active matter.

    Science.gov (United States)

    Takatori, S C; Yan, W; Brady, J F

    2014-07-11

    We discover a new contribution to the pressure (or stress) exerted by a suspension of self-propelled bodies. Through their self-motion, all active matter systems generate a unique swim pressure that is entirely athermal in origin. The origin of the swim pressure is based upon the notion that an active body would swim away in space unless confined by boundaries-this confinement pressure is precisely the swim pressure. Here we give the micromechanical basis for the swim stress and use this new perspective to study self-assembly and phase separation in active soft matter. The swim pressure gives rise to a nonequilibrium equation of state for active matter with pressure-volume phase diagrams that resemble a van der Waals loop from equilibrium gas-liquid coexistence. Theoretical predictions are corroborated by Brownian dynamics simulations. Our new swim stress perspective can help analyze and exploit a wide class of active soft matter, from swimming bacteria to catalytic nanobots to molecular motors that activate the cellular cytoskeleton.

  17. A transparent bending-insensitive pressure sensor

    Science.gov (United States)

    Lee, Sungwon; Reuveny, Amir; Reeder, Jonathan; Lee, Sunghoon; Jin, Hanbit; Liu, Qihan; Yokota, Tomoyuki; Sekitani, Tsuyoshi; Isoyama, Takashi; Abe, Yusuke; Suo, Zhigang; Someya, Takao

    2016-05-01

    Measuring small normal pressures is essential to accurately evaluate external stimuli in curvilinear and dynamic surfaces such as natural tissues. Usually, sensitive and spatially accurate pressure sensors are achieved through conformal contact with the surface; however, this also makes them sensitive to mechanical deformation (bending). Indeed, when a soft object is pressed by another soft object, the normal pressure cannot be measured independently from the mechanical stress. Here, we show a pressure sensor that measures only the normal pressure, even under extreme bending conditions. To reduce the bending sensitivity, we use composite nanofibres of carbon nanotubes and graphene. Our simulations show that these fibres change their relative alignment to accommodate bending deformation, thus reducing the strain in individual fibres. Pressure sensitivity is maintained down to a bending radius of 80 μm. To test the suitability of our sensor for soft robotics and medical applications, we fabricated an integrated sensor matrix that is only 2 μm thick. We show real-time (response time of ∼20 ms), large-area, normal pressure monitoring under different, complex bending conditions.

  18. Assessment of fiber optic pressure sensors

    Energy Technology Data Exchange (ETDEWEB)

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

    1995-04-01

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

  19. Atmospheric pressure plasma research activity in korea

    International Nuclear Information System (INIS)

    Plasma is generated by electrical discharge. Most plasma generation has been carried out at low-pressure gas typically less than one millionth of atmospheric pressure. Plasmas are in general generated from impact ionizations of neutral gas molecules by accelerated electrons. The energy gain of electrons accelerated in an electrical field is proportional to the mean free path. Electrons gain more energy at low-pressure gas and generate plasma easily by the ionization of neutrals, because the mean free path is longer. For this reason conventional plasma generation is carried out at low pressures. However, many practical applications require plasmas at high-pressure. In order to avoid the requirement for vacuum pump, researchers in Korea start to develop plasmas in high-pressure chambers where the pressure is 1 atmosphere or greater. Material processing, environmental protection/restoration and improved energy production efficiency using plasma are only possible for inexpensive bulk plasmas. We thus generate plasmas by new methods and plan to set foundations for new plasma technologies for 21st century industries. This technological research will play a central role in material processing, environmental and energy production industries

  20. A transparent bending-insensitive pressure sensor.

    Science.gov (United States)

    Lee, Sungwon; Reuveny, Amir; Reeder, Jonathan; Lee, Sunghoon; Jin, Hanbit; Liu, Qihan; Yokota, Tomoyuki; Sekitani, Tsuyoshi; Isoyama, Takashi; Abe, Yusuke; Suo, Zhigang; Someya, Takao

    2016-05-01

    Measuring small normal pressures is essential to accurately evaluate external stimuli in curvilinear and dynamic surfaces such as natural tissues. Usually, sensitive and spatially accurate pressure sensors are achieved through conformal contact with the surface; however, this also makes them sensitive to mechanical deformation (bending). Indeed, when a soft object is pressed by another soft object, the normal pressure cannot be measured independently from the mechanical stress. Here, we show a pressure sensor that measures only the normal pressure, even under extreme bending conditions. To reduce the bending sensitivity, we use composite nanofibres of carbon nanotubes and graphene. Our simulations show that these fibres change their relative alignment to accommodate bending deformation, thus reducing the strain in individual fibres. Pressure sensitivity is maintained down to a bending radius of 80 μm. To test the suitability of our sensor for soft robotics and medical applications, we fabricated an integrated sensor matrix that is only 2 μm thick. We show real-time (response time of ∼20 ms), large-area, normal pressure monitoring under different, complex bending conditions.

  1. Particle Pressures in Fluidized Beds. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Campbell, C.S.; Rahman, K.; Jin, C.

    1996-09-01

    This project studies the particle pressure, which may be thought of as the force exerted by the particulate phase of a multiphase mixture, independently of that exerted by other phases. The project is divided into two parts, one concerning gas and the other liquid fluidized beds. Previous work on gas fluidized beds had suggested that the particle pressures are generated by bubbling action. Thus, for these gas fluidized bed studies, the particle pressure is measured around single bubbles generated in 2-D fluidized beds, using special probes developed especially for this purpose. Liquid beds are immune from bubbling and the particle pressures proved too small to measure directly. However, the major interest in particle pressures in liquid beds lies in their stabilizing effect that arises from the effective elasticity (the derivative of the particle pressure with respect to the void fraction): they impart to the bed. So rather than directly measure the particle pressure, we inferred the values of the elasticity from measurements of instability growth in liquid beds the inference was made by first developing a generic stability model (one with all the normally modeled coefficients left undetermined)and then working backwards to determine the unknown coefficients, including the elasticity.

  2. Non-invasive model-based estimation of aortic pulse pressure using suprasystolic brachial pressure waveforms.

    Science.gov (United States)

    Lowe, A; Harrison, W; El-Aklouk, E; Ruygrok, P; Al-Jumaily, A M

    2009-09-18

    Elevated central arterial (aortic) blood pressure is related to increased risk of cardiovascular disease. Methods of non-invasively estimating this pressure would therefore be helpful in clinical practice. To achieve this goal, a physics-based model is derived to correlate the arterial pressure under a suprasystolic upper-arm cuff to the aortic pressure. The model assumptions are particularly applicable to the measurement method and result in a time-domain relation with two parameters, namely, the wave propagation transit time and the reflection coefficient at the cuff. Central pressures estimated by the model were derived from completely automatic, non-invasive measurement of brachial blood pressure and suprasystolic waveform and were compared to simultaneous invasive catheter measurements in 16 subjects. Systolic blood pressure agreement, mean (standard deviation) of difference was -1 (7)mmHg. Diastolic blood pressure agreement was 4 (4)mmHg. Correlation between estimated and actual central waveforms was greater than 90%. Individualization of model parameters did not significantly improve systolic and diastolic pressure agreement, but increased waveform correlation. Further research is necessary to confirm that more accurate brachial pressure measurement improves central pressure estimation. PMID:19665136

  3. Safe retaining pressures for pressurized tunnel face using nonlinear failure criterion and reliability theory

    Institute of Scientific and Technical Information of China (English)

    YANG Xiao-li; YAO Cong; ZHANG Jia-hua

    2016-01-01

    Based on the active failure mechanism and passive failure mechanism for a pressurized tunnel face, the analytical solutions of the minimum collapse pressure and maximum blowout pressure that could maintain the stability of pressurized tunnel faces were deduced using limit analysis in conjunction with nonlinear failure criterion under the condition of pore water pressure. Due to the objective existence of the parameter randomness of soil, the statistical properties of random variables were determined by the maximum entropy principle, and the Monte Carlo method was employed to calculate the failure probability of a pressurized tunnel. The results show that the randomness of soil parameters exerts great influence on the stability of a pressurized tunnel, which indicates that the research should be done on the topic of determination of statistical distribution for geotechnical parameters and the level of variability. For the failure probability of a pressurized tunnel under multiple failure modes, the corresponding safe retaining pressures and optimal range of safe retaining pressures are calculated by introducing allowable failure probability and minimum allowable failure probability. The results can provide practical use in the pressurized tunnel engineering.

  4. Health Behavior Change after Blood Pressure Feedback.

    Directory of Open Access Journals (Sweden)

    Jia Pu

    Full Text Available Better understanding is needed for antihypertensive medication initiation and lifestyle modification among younger populations with elevated blood pressure. This study aimed to assess health behavior change after receiving a report of elevated blood pressure among African Americans and Caucasians younger than 50 years old. We used the Coronary Artery Risk Development in Young Adults (CARDIA repository dataset. By examination year twenty, 424 out of 2,478 Caucasian and 2,637 African American participants had received feedback from the CARDIA study due to elevated blood pressure readings. Blood pressure was measured by trained CARDIA researchers at the participant's home and was repeatedly recorded at seven examinations over twenty years. A feedback/referral letter was sent to participants with an elevated blood pressure reading. On average, participants first had an elevated blood pressure reading at the age of 34. After receiving the feedback letter, 44% of the previously undiagnosed participants received a formal diagnosis. In addition, 23% initiated the use of antihypertensive medication if they had not received medication treatment before. Among the participants with at-risk lifestyle behaviors, 40% reduced alcohol consumption, 14% increased exercise level, 11% stopped smoking, and 8% reached normal weight. While none of the studied patient factors were associated with lifestyle modification, age had a positive impact on antihypertensive medication initiation (p<0.05. We found no evidence of differences in health behavior change between African American and Caucasian participants after receiving the feedback letter. This research is one of the first to study what followed after receiving a feedback letter about elevated blood pressure outside of healthcare settings. Although additional referral care and behavior interventions are needed to facilitate medication initiation and lifestyle modification, our observations suggest that providing

  5. Beat-to-Beat Blood Pressure Monitor

    Science.gov (United States)

    Lee, Yong Jin

    2012-01-01

    This device provides non-invasive beat-to-beat blood pressure measurements and can be worn over the upper arm for prolonged durations. Phase and waveform analyses are performed on filtered proximal and distal photoplethysmographic (PPG) waveforms obtained from the brachial artery. The phase analysis is used primarily for the computation of the mean arterial pressure, while the waveform analysis is used primarily to obtain the pulse pressure. Real-time compliance estimate is used to refine both the mean arterial and pulse pressures to provide the beat-to-beat blood pressure measurement. This wearable physiological monitor can be used to continuously observe the beat-to-beat blood pressure (B3P). It can be used to monitor the effect of prolonged exposures to reduced gravitational environments and the effectiveness of various countermeasures. A number of researchers have used pulse wave velocity (PWV) of blood in the arteries to infer the beat-to-beat blood pressure. There has been documentation of relative success, but a device that is able to provide the required accuracy and repeatability has not yet been developed. It has been demonstrated that an accurate and repeatable blood pressure measurement can be obtained by measuring the phase change (e.g., phase velocity), amplitude change, and distortion of the PPG waveforms along the brachial artery. The approach is based on comparing the full PPG waveform between two points along the artery rather than measuring the time-of-flight. Minimizing the measurement separation and confining the measurement area to a single, well-defined artery allows the waveform to retain the general shape between the two measurement points. This allows signal processing of waveforms to determine the phase and amplitude changes. Photoplethysmography, which measures changes in arterial blood volume, is commonly used to obtain heart rate and blood oxygen saturation. The digitized PPG signals are used as inputs into the beat-to-beat blood

  6. Pressure Safety Program Implementation at ORNL

    Energy Technology Data Exchange (ETDEWEB)

    Lower, Mark [ORNL; Etheridge, Tom [ORNL; Oland, C. Barry [XCEL Engineering, Inc.

    2013-01-01

    The Oak Ridge National Laboratory (ORNL) is a US Department of Energy (DOE) facility that is managed by UT-Battelle, LLC. In February 2006, DOE promulgated worker safety and health regulations to govern contractor activities at DOE sites. These regulations, which are provided in 10 CFR 851, Worker Safety and Health Program, establish requirements for worker safety and health program that reduce or prevent occupational injuries, illnesses, and accidental losses by providing DOE contractors and their workers with safe and healthful workplaces at DOE sites. The regulations state that contractors must achieve compliance no later than May 25, 2007. According to 10 CFR 851, Subpart C, Specific Program Requirements, contractors must have a structured approach to their worker safety and health programs that at a minimum includes provisions for pressure safety. In implementing the structured approach for pressure safety, contractors must establish safety policies and procedures to ensure that pressure systems are designed, fabricated, tested, inspected, maintained, repaired, and operated by trained, qualified personnel in accordance with applicable sound engineering principles. In addition, contractors must ensure that all pressure vessels, boilers, air receivers, and supporting piping systems conform to (1) applicable American Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel Code (2004) Sections I through XII, including applicable code cases; (2) applicable ASME B31 piping codes; and (3) the strictest applicable state and local codes. When national consensus codes are not applicable because of pressure range, vessel geometry, use of special materials, etc., contractors must implement measures to provide equivalent protection and ensure a level of safety greater than or equal to the level of protection afforded by the ASME or applicable state or local codes. This report documents the work performed to address legacy pressure vessel deficiencies and comply

  7. Dynamic pressure measures for long pipeline leak detection

    Energy Technology Data Exchange (ETDEWEB)

    Likun Wang; Hongchao Wang; Min Xiong; Bin Xu; Dongjie Tan; Hengzhang Zhou [PetroChina Pipeline Company, Langfang (China). R and D Center

    2009-07-01

    Pipeline leak detection method based on dynamic pressure is studied. The feature of dynamic pressure which is generated by the leakage of pipeline is analyzed. The dynamic pressure method is compared with the static pressure method for the advantages and disadvantages in pipeline leak detection. The dynamic pressure signal is suitable for pipeline leak detection for quick-change of pipeline internal pressure. Field tests show that the dynamic pressure method detects pipeline leak rapidly and precisely. (author)

  8. STRESS ANALYSIS AND BURST PRESSURE DETERMINATION OF TWO LAYER COMPOUND PRESSURE VESSEL

    Directory of Open Access Journals (Sweden)

    HARERAM LOHAR

    2013-02-01

    Full Text Available Multilayer pressure vessel is designed to work under high-pressure condition. This paper introduces the stress analysis and the burst pressure calculation of a two-layer shrink fitted pressure vessel. In the shrink-fitting problems, considering long hollow cylinders, the plane strain hypothesis can be regarded as more natural. Generally hoops stress distribution is non-linear and sharply reduced toward the outer surface. By shrink fitting concentric shells towards the inner shells are placed in residual compression so that the initial compressive hoop stress must be relieved by internal pressure before hoop tensile stress are developed. Therefore the maximum hoop stress will be reduced, resulting more burst pressure. The analytical results of stress distribution and burst pressure is calculated and validated by ANSYS Workbench results.

  9. Beat Pressure and Comparing it with Ascending Aorta Pressure in Normal and Abnormal Conditions

    CERN Document Server

    Ghasemalizadeh, Omid; Firoozabadi, Bahar; Sajadi, Behrang; Zolfonoon, Ali

    2014-01-01

    Lumped method (Electrical analogy) is a quick and easy way to model human cardiovascular system. In this paper Lumped method is used for simulating a complete model. It describes a 36-vessel model and cardiac system of human body with details that could show hydrodynamic parameters of cardiovascular system. Also this paper includes modeling of pulmonary, atrium, left and right ventricles with their equivalent circuits. Exact modeling of right and left ventricles pressure with division of ascending aorta into 27 segments increases the accuracy of our simulation. In this paper we show that a calculated pressure for aorta from our complex circuit is near to measured pressure by using advanced medical instruments. Also it is shown that pressure graph from brachial is so near to aortic pressure because of this its pressure signal is usable instead of aortic pressure. Furthermore, obstruction in ascending aorta, brachial and its effects has been showed in different figures.

  10. Blast wave parameters at diminished ambient pressure

    Science.gov (United States)

    Silnikov, M. V.; Chernyshov, M. V.; Mikhaylin, A. I.

    2015-04-01

    Relation between blast wave parameters resulted from a condensed high explosive (HE) charge detonation and a surrounding gas (air) pressure has been studied. Blast wave pressure and impulse differences at compression and rarefaction phases, which traditionally determine damage explosive effect, has been analyzed. An initial pressure effect on a post-explosion quasi-static component of the blast load has been investigated. The analysis is based on empirical relations between blast parameters and non-dimensional similarity criteria. The results can be directly applied to flying vehicle (aircraft or spacecraft) blast safety analysis.

  11. Plantar pressure cartography reconstruction from 3 sensors.

    Science.gov (United States)

    Abou Ghaida, Hussein; Mottet, Serge; Goujon, Jean-Marc

    2014-01-01

    Foot problem diagnosis is often made by using pressure mapping systems, unfortunately located and used in the laboratories. In the context of e-health and telemedicine for home monitoring of patients having foot problems, our focus is to present an acceptable system for daily use. We developed an ambulatory instrumented insole using 3 pressures sensors to visualize plantar pressure cartographies. We show that a standard insole with fixed sensor position could be used for different foot sizes. The results show an average error measured at each pixel of 0.01 daN, with a standard deviation of 0.005 daN.

  12. The vapor pressure of iron pentacarbonyl

    Science.gov (United States)

    Gilbert, A. G.; Sulzmann, K. G. P.

    1974-01-01

    Vapor pressure measurements have been made on pure iron pentacarbonyl between +31 and -19 C. The experimental results may be expressed by the logarithm of pressure (mm Hg) to the base 10 equals -(2096.7 K/T) + 8.4959, which corresponds to a heat of vaporization for the liquid carbonyl of delta H ? (9.588 plus or minus 0.12) kcal/mole. This result confirms and extends the earlier measurements made by Trautz and Badstuebner between 0 and 140 C. The need for careful purification of commercially available iron pentacarbonyl is emphasized, particularly for establishing the correct vapor pressure below 45 C.

  13. Centrifugal pump inlet pressure site affects measurement.

    Science.gov (United States)

    Augustin, Simon; Horton, Alison; Butt, Warwick; Bennett, Martin; Horton, Stephen

    2010-09-01

    During extracorporeal life support (ECLS), blood is exposed to a myriad of unphysiological factors that can affect outcome. One aspect of this is the sub-atmospheric pressure generated by the ECLS pump and imparted to blood elements along the pump inlet line. This pressure can be measured on the inlet line close to the pump head by adding a connector, or at the venous cannula connection site. We compared the two measurement sites located at both points; between the venous cannula-inlet tubing and inlet tubing-pump, with a range of cannulae and flows. We also investigated the effects on inlet pressure from pump afterload and increasing inlet tubing length.

  14. Pressure balance at the magnetopause: Experimental studies

    OpenAIRE

    Suvorova, A. V.; Dmitriev, A. V.

    2011-01-01

    The pressure balance at the magnetopause is formed by magnetic field and plasma in the magnetosheath, on one side, and inside the magnetosphere, on the other side. In the approach of dipole earth's magnetic field configuration and gas-dynamics solar wind flowing around the magnetosphere, the pressure balance predicts that the magnetopause distance R depends on solar wind dynamic pressure Pd as a power low R ~ Pd^alpha, where the exponent alpha=-1/6. In the real magnetosphere the magnetic file...

  15. Magnetic and Superconducting Materials at High Pressures

    Energy Technology Data Exchange (ETDEWEB)

    Struzhkin, Viktor V. [Carnegie Inst. of Washington, Washington, DC (United States)

    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

  16. PRESSURE CHARACTERISTICS OF CAVITATION CONTROL BY AERATION

    Institute of Scientific and Technical Information of China (English)

    DONG Zhi-yong; LU Yang-quan; JU Wen-jie; CAI Xin-ming; DING Chun-sheng

    2005-01-01

    This experimental investigation was systematically conducted with the aid of a non-circulating water tunnel in the Hydraulics Laboratory at Zhejiang University of Technology in China.The test velocity is between 20m/s and 40m/s.The least air concentration to prevent cavitation erosion lies between 1.7% and 4.5%.Pressure waveforms with and without aeration in cavitation and cavitation erosion regions were measured.Time-averaged pressure profiles with and without aeration were compared.Pressure characteristics corresponding to least air concentration to prevent cavitation erosion in cavitation and cavitation erosion regions were analyzed.

  17. Intraluminal pressure profiles during flexible ureterorenoscopy

    DEFF Research Database (Denmark)

    Jung, Helene; Osther, Palle J S

    2015-01-01

    BACKGROUND: Irrigation and instrumentation during ureterorenoscopic procedures may cause increased pressure in the renal pelvis (PP) with potential harmful adverse effects. In order to assess the pressure increases during ureterorenoscopy, we measured the intraluminal renal pelvic pressure during...... retrograde intrarenal stone surgery (RIRS). METHODS: Twelve patients admitted for RIRS were included. Irrigation rate was standardized to 8 ml/min. A ureteral catheter was retrogradely placed in the renal pelvis for PP measurements. PP was measured one time per second during insertion of the Storz Flex-X2...

  18. Effect of Pressure on Minimum Fluidization Velocity

    Institute of Scientific and Technical Information of China (English)

    Zhu Zhiping; Na Yongjie; Lu Qinggang

    2007-01-01

    Minimum fluidization velocity of quartz sand and glass bead under different pressures of 0.5, 1.0, 1.5 and 2.0 Mpa were investigated. The minimum fluidization velocity decreases with the increasing of pressure. The influence of pressure to the minimum fluidization velocities is stronger for larger particles than for smaller ones.Based on the test results and Ergun equation, an experience equation of minimum fluidization velocity is proposed and the calculation results are comparable to other researchers' results.

  19. Superconductivity in lanthanum chalcogenides under pressure

    International Nuclear Information System (INIS)

    In this thesis the pressure dependence of the superconducting transition temperature of La3S4, La3Se4, La3Te4, La2Se2S2, and La2Sesub(3,6) Tesub(0,4) is investigated up to 4,5 GPa. A pressure cell is reported which allows also the measurement of the magnetic susceptibility under pressure. The calculated density of states describe the increase of the critical temperature very well in the frame of Mc Millans equation. (TWO)

  20. An Optical Pressure Sensor Based on MEMS

    Institute of Scientific and Technical Information of China (English)

    Tong Zhang; Sheng Qiang; Frank Lewis; Yalin Wu; Xiaozhu Chi

    2006-01-01

    An optical fiber pressure sensor has been developed for the measurement in human body. The sensing element is possessed of a membrane structure, which is fabricated by micromachining. The fabrication process includes anisotropic wet etching on the silicon wafer. For the transmitting source and signal light, a multimode optical fiber 50/125 μm (core/clad) in diameter was used. The intensity of the light reflected back into the fiber varies with the membrane deflection, which is a function of pressure. The deflection of the membrane by applied pressure can be mathematically described.

  1. Pressure Hull Analysis under Shock Loading

    Directory of Open Access Journals (Sweden)

    Ya-Jung Lee

    2008-01-01

    Full Text Available The hull of high performance submarines must resist underwater shock loading due to exploding torpedoes or depth bombs. An underwater shock involving an initial shock wave and successive bubble pulsating waves is so complex that a theoretical technique for deriving shock pressure distribution is required for improving simulation efficiency. Complete shock loading is obtained theoretically in this work, and responses of a submarine pressure hull are calculated using ABAQUS USA (Underwater Shock Analysis codes. In the long run, this deflection and stress data will assist in examining the structural arrangement of the submarine pressure hull.

  2. Evaluation of Formation Damage and Assessment of Well Productivity of Oredo Field, Edo State, Nigeria

    Directory of Open Access Journals (Sweden)

    Omotara O. Oluwagbenga

    2015-02-01

    Full Text Available Formation damage canincurconsiderable cost for remediation and deferred production. Thorough understanding of the formation damage mechanisms, stringent measures for its control and prevention, and effective and efficient treatments are the keys for optimum production strategies for oil and gas fields. WELL 4X was investigated in this study to properly diagnosed and evaluate productivity in OREDO FIELD and Bottom Hole Pressure survey was used from Bottom Hole Pressure analysis in addition to the information of the well production history and reservoir data available to determine and assess the extent of the formation damage in the well. The WELL 4X was stimulated using Acid Foam Diversion Techniques to enhance reservoir productivity and increase economic operations. The stimulation job done on the well showed a peak increase of production from 850 bbl/day to 3200 b/d before it declined to 2150 bbl/day, and finally maintained an average stabilized rate of 2000 bbl/day. It has to be established that the treatment method on WELL 4X using Acid Foam Diversion Techniques and the Bottom Hole Pressure survey conducted on the WELL 4X in OREDO FIELD is found to be efficient in the determination and evaluation of formation damage.

  3. DIASTOLIC BLOOD PRESSURE OR ACTUALLY IT IS BASELINE SYSTOLIC BLOOD PRESSURE?

    Directory of Open Access Journals (Sweden)

    R.Vinodh Rajkumar

    2015-08-01

    Full Text Available Blood pressure measuring represents a routine investigation in general medicine. Nokolai Korotkoff was only 31 years old when he made a short presentation to the Scientific Meeting of the Military Hospital of the Academy on 5 November 1905 concerning an easy non-invasive method of blood pressure (BP measurement, entitled ‘Concerning the problems of the methods of blood pressure measurement’. If the pressure in the cuff is relieved, blood starts coming through the compressed arterial segment during systole and causes auscultatory sound and, the first sound, which, in Korotkoff’s opinion, is a measurement of systolic blood pressure. In the same BP measurement, when normal blood flow is fully restored, the auscultatory sounds disappear and, the last sound, which, in Korotkoff's opinion is a measurement of diastolic blood pressure. Listening to Korotkoff sounds (K-sounds to determine systolic and diastolic blood pressure (BP has been the standard for noninvasive BP measurement in medical practices for nearly 100 years and it is the essential tool used for evaluation and assessment of patients with hypertension and risks of cardiovascular diseases (CVD by physicians and nurses despite limited understanding of the nature of K-sounds. This article focuses particularly on the cardiovascular biomechanics of the first and last auscultatory sound and suggests two new terminologies; Highest systolic blood pressure and Baseline systolic blood pressure to represent the systolic pressure and diastolic pressure, respectively. Experimenting blood pressures on the basis of these two new suggested terminologies may reveal various additional undiscovered aspects of normal BP and abnormal BP. KEY WORDS: Highest systolic blood pressure, Baseline systolic blood pressure, Korotkoff sounds

  4. EXPERIMENTAL STUDY ON INFLUENCE OF SUPPLIED PRESSURE FLUCTUATION ON OUTPUT ARACTERISTIC OF PRESSURE CONTROL SYSTEM OF ROLLING MILL

    Institute of Scientific and Technical Information of China (English)

    1998-01-01

    The infulence of supplied pressure fluctuation on output accuracy for the electro-hydraulic pressure control system of the rolling mill is discussed.Based on the bond graph theory and experimental study,the relationship between the variation of system output pressure and the supplied pressure fluctuation and the influence of the system bandwidth on system output pressure are provided.A theoretical base for determining the allowable fluctuation range of pressure and accurate design of constant pressure source system is obtained.

  5. Thermogravimetric measurements of liquid vapor pressure

    International Nuclear Information System (INIS)

    Highlights: ► Rapid determination of vapor pressure by TGA. ► Demonstration of limitations of currently available approaches in literature. ► New model for vapor pressure assessment of small size samples in TGA. ► New model accounts for vapor diffusion and sample geometry and measures vapor pressure normally within 10%. - Abstract: A method was developed using thermo-gravimetric analysis (TGA) to determine the vapor pressure of volatile liquids. This is achieved by measuring the rate of evaporation (mass loss) of a pure liquid contained within a cylindrical pan. The influence of factors like sample geometry and vapor diffusion on evaporation rate are discussed. The measurement can be performed across a wide range of temperature yielding reasonable results up to 10 kPa. This approach may be useful as a rapid and automatable method for measuring the volatility of flavor and fragrance raw materials.

  6. Evaporation of urea at atmospheric pressure.

    Science.gov (United States)

    Bernhard, Andreas M; Czekaj, Izabela; Elsener, Martin; Wokaun, Alexander; Kröcher, Oliver

    2011-03-31

    Aqueous urea solution is widely used as reducing agent in the selective catalytic reduction of NO(x) (SCR). Because reports of urea vapor at atmospheric pressure are rare, gaseous urea is usually neglected in computational models used for designing SCR systems. In this study, urea evaporation was investigated under flow reactor conditions, and a Fourier transform infrared (FTIR) spectrum of gaseous urea was recorded at atmospheric pressure for the first time. The spectrum was compared to literature data under vacuum conditions and with theoretical spectra of monomolecular and dimeric urea in the gas phase calculated with the density functional theory (DFT) method. Comparison of the spectra indicates that urea vapor is in the monomolecular form at atmospheric pressure. The measured vapor pressure of urea agrees with the thermodynamic data obtained under vacuum reported in the literature. Our results indicate that considering gaseous urea will improve the computational modeling of urea SCR systems.

  7. Pressure-assisted thermal sterilization of soup

    Science.gov (United States)

    Shibeshi, Kidane; Farid, Mohammed M.

    2010-12-01

    The overall efficiency of an existing scale-up pressure-assisted thermal sterilization (PATS) unit was investigated with regards to inactivation of Geobacillus stearothermophilus spores suspended in pumpkin soup. The PATS unit is a double pipe heat exchanger in which the soup is pumped into its inner high pressure tube and constrained by two high pressure valves, while steam is continuously passed through the annular region to heat the content. The technology is based on pressure generation by thermal expansion of the liquid in an enclosure. In this work, the addition of an air line to push the treated liquid food out of the existing PATS unit has improved the overall quality of the treated samples, as evidenced by achieving higher log reduction of the spores. Compared with thermal processing, the application of PATS shows the potential for lowering the thermal treatment temperature, offering improved food quality.

  8. An implantable blood pressure and flow transmitter.

    Science.gov (United States)

    Rader, R. D.; Meehan, J. P.; Henriksen, J. K. C.

    1973-01-01

    A miniature totally implantable FM/FM telemetry system has been developed to simultaneously measure blood pressure and blood flow, thus providing an appreciation of the hemodynamics of the circulation to the entire body or to a particular organ. Developed for work with animal subjects, the telemetry system's transmission time is controlled by an RF signal that permits an operating life of several months. Pressure is detected by a miniature intravascular transducer and flow is detected by an extravascular interferometric ultrasonic technique. Both pressure and flow are calibrated prior to implanting. The pressure calibration can be checked after the implanting by cannulation; flow calibration can be verified only at the end of the experiment by determining the voltage output from the implanted sensing system as a function of several measured flow rates. The utility of this device has been established by its use in investigating canine renal circulation during exercise, emotional encounters, administration of drugs, and application of accelerative forces.

  9. Dependency of radon entry on pressure difference

    International Nuclear Information System (INIS)

    Radon levels, ventilation rate and pressure differences were monitored continuously in four apartment houses with different ventilation systems. Two of them were ventilated by mechanical exhaust, one by mechanical supply and exhaust, and one by natural ventilation. The two-storey houses were constructed from concrete elements on a slab and located on a gravel esker. It was surprising to find that increasing the ventilation rate increased levels of radon in the apartments. Increased ventilation caused increased outdoor-indoor pressure difference, which in turn increased the entry rate of radon and counteracted the diluting effect of ventilation. The increase was significant when the outdoor-indoor pressure difference exceeded 5 Pa. Especially in the houses with mechanical exhaust ventilation the pressure difference was the most important factor of radon entry rate, and contributed up to several hundred Bq m-3h-1. (Author)

  10. SELECTIVE PRESSURE IMPRESSION TECHNIQUE: AN OVERVIEW

    Directory of Open Access Journals (Sweden)

    Arun

    2014-07-01

    Full Text Available Impression is basically an interaction between tissues and impression material. The variety of impression materials and the range of working characteristics of these materials, make possible the development of impression procedures best suited for specific conditions. Our method for making impressions should be based on the basic principles of maximum area coverage and intimate contact so as to achieve the objectives of retention, support, stability, esthetics, preservation of ridge (supporting structures. Various impression techniques have been mentioned in the literature for recording impression of edentulous ridges. These techniques have been classified by different authors as functional, mucostatic, mucocompressive, selective pressure, minimal pressure etc. However none of these techniques has been designated as the ‘time best’ for a particular patient though selective pressure technique has got much attention in the literature. This article is presenting a critical review on the selective pressure impression technique used for edentulous patients.

  11. High Blood Pressure May Hike Dementia Risk

    Science.gov (United States)

    ... fullstory_161398.html High Blood Pressure May Hike Dementia Risk New statement from American Heart Association warns ... in middle age, might open the door to dementia, the American Heart Association warns in a new ...

  12. New pressure cell for ultrasonic measurements

    Science.gov (United States)

    Kepa, Michal; Huxley, Andrew; Kamenev, Konstantin

    2013-06-01

    Ultrasonic interferometry at high pressure remains a technical challenge as the small sample space requires the application of very high-frequency ultrasound. Here we present the design of a new cell developed specifically for ultrasonic measurements of single crystals at low temperatures (2K) and high pressures (5GPa). The design allows greater sample space (compared to a conventional diamond anvil cell) and simultaneous measurement of ultrasonic attenuation and velocities. Coupling the fine transducers to spherical sapphire anvils reduces background and enables different polarizations of the ultrasonic wave to be measured at the same pressure and temperature conditions. The results are used to deduce the elastic, electronic and magnetic properties of a crystal. The finite element analysis of the cell together with the pressure calibration curves and test data taken on UGe2 are presented.

  13. NOAA NOS SOS, EXPERIMENTAL - Barometric Pressure

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The NOAA NOS SOS server is part of the IOOS DIF SOS Project. The stations in this dataset have barometric pressure data. *These services are for testing and...

  14. Distributed pressure sensors for a urethral catheter.

    Science.gov (United States)

    Ahmadi, Mahdi; Rajamani, Rajesh; Timm, Gerald; Sezen, A S

    2015-08-01

    A flexible strip that incorporates multiple pressure sensors and is capable of being fixed to a urethral catheter is developed. The urethral catheter thus instrumented will be useful for measurement of pressure in a human urethra during urodynamic testing in a clinic. This would help diagnose the causes of urinary incontinence in patients. Capacitive pressure sensors are fabricated on a flexible polyimide-copper substrate using surface micromachining processes and alignment/assembly of the top and bottom portions of the sensor strip. The developed sensor strip is experimentally evaluated in an in vitro test rig using a pressure chamber. The sensor strip is shown to have adequate sensitivity and repeatability. While the calibration factors for the sensors on the strip vary from one sensor to another, even the least sensitive sensor has a resolution better than 0.1 psi. PMID:26738054

  15. Tearing mode stability calculations with pressure flattening

    CERN Document Server

    Ham, C J; Cowley, S C; Hastie, R J; Hender, T C; Liu, Y Q

    2013-01-01

    Calculations of tearing mode stability in tokamaks split conveniently into an external region, where marginally stable ideal MHD is applicable, and a resonant layer around the rational surface where sophisticated kinetic physics is needed. These two regions are coupled by the stability parameter. Pressure and current perturbations localized around the rational surface alter the stability of tearing modes. Equations governing the changes in the external solution and - are derived for arbitrary perturbations in axisymmetric toroidal geometry. The relationship of - with and without pressure flattening is obtained analytically for four pressure flattening functions. Resistive MHD codes do not contain the appropriate layer physics and therefore cannot predict stability directly. They can, however, be used to calculate -. Existing methods (Ham et al. 2012 Plasma Phys. Control. Fusion 54 025009) for extracting - from resistive codes are unsatisfactory when there is a finite pressure gradient at the rational surface ...

  16. Pancreas tumor interstitial pressure catheter measurement

    Science.gov (United States)

    Nieskoski, Michael D.; Gunn, Jason; Marra, Kayla; Trembly, B. Stuart; Pogue, Brian W.

    2016-03-01

    This paper highlights the methodology in measuring interstitial pressure in pancreatic adenocarcinoma tumors. A Millar Mikrotip pressure catheter (SPR-671) was used in this study and a system was built to amplify and filter the output signal for data collection. The Millar pressure catheter was calibrated prior to each experiment in a water column at 37°C, range of 0 to 60 inH2O (112 mmHg), resulting in a calibration factor of 33 mV / 1 inH2O. The interstitial pressures measured in two orthotopically grown pancreatic adenocarcinoma tumor were 57 mmHg and 48 mmHg, respectively. Verteporfin uptake into the pancreatic adenocarcinoma tumor was measured using a probe-based experimental dosimeter.

  17. Dependency of radon entry on pressure difference

    Science.gov (United States)

    Kokotti, H.; Kalliokoski, P.; Jantunen, M.

    Radon levels, ventilation rate and pressure differences were monitored continuously in four apartment houses with different ventilation systems. Two of them were ventilated by mechanical exhaust, one by mechanical supply and exhaust, and one by natural ventilation. The two-storey houses were constructed from concrete elements on a slab and located on a gravel esker. It was surprising to find that increasing the ventilation rate increased levels of radon in the apartments. Increased ventilation caused increased outdoor-indoor pressure difference, which in turn increased the entry rate of radon and counteracted the diluting effect of ventilation. The increase was significant when the outdoor-indoor pressure difference exceeded 5 Pa. Especially in the houses with mechanical exhaust ventilation the pressure difference was the most important factor of radon entry rate, and contributed up to several hundred Bq m -3 h -1.

  18. Ram Pressure Stripping: The Long Goodbye

    Science.gov (United States)

    Tonnesen, Stephanie; Lu, Yu; Benson, Andrew; Peter, Annika; Boylan-Kolchin, Michael; Wetzel, Andrew R.; Weisz, Daniel R.

    2016-01-01

    What turns off star formation in satellite galaxies? Ram pressure stripping, the removal of a galaxy's gas through direct interaction with the gas halo in which it orbits, is an attractive quenching mechanism, particularly in the Milky Way halo where the radial distribution of quenching is dramatic. However, many implementations of this process in semi-analytic models result in overly-rapid gas removal when compared with observations. We use high resolution hydrodynamical simulations run with Enzo to parameterize the stripping of disk and halo gas from an orbiting satellite galaxy for use in the semi-analytic modeling code Galacticus. We find that using the instantaneous ram pressure overestimates the amount of gas that is stripped, and present a physically-motivated module for including ram pressure stripping in semi-analytic models that uses the integral of the ram pressure experienced by a satellite galaxy. We will compare our results to observations of the Milky Way satellites.

  19. Micromachined pressure sensors: Review and recent developments

    Energy Technology Data Exchange (ETDEWEB)

    Eaton, W.P.; Smith, J.H. [Sandia National Labs., Albuquerque, NM (United States). Intelligent Micromachines Dept.

    1997-03-01

    Since the discovery of piezoresistivity in silicon in the mid 1950s, silicon-based pressure sensors have been widely produced. Micromachining technology has greatly benefited from the success of the integrated circuits industry, burrowing materials, processes, and toolsets. Because of this, microelectromechanical systems (MEMS) are now poised to capture large segments of existing sensor markets and to catalyze the development of new markets. Given the emerging importance of MEMS, it is instructive to review the history of micromachined pressure sensors, and to examine new developments in the field. Pressure sensors will be the focus of this paper, starting from metal diaphragm sensors with bonded silicon strain gauges, and moving to present developments of surface-micromachined, optical, resonant, and smart pressure sensors. Considerations for diaphragm design will be discussed in detail, as well as additional considerations for capacitive and piezoresistive devices.

  20. High Toughness Light Weight Pressure Vessel Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Proposed is a pressure vessel with 25% better Fracture Strength over equal strength designed Fiberglass to help reduce 10 to 25% weight for aerospace use. Phase I...