Sample records for relief valve means

  1. Adjustable safety relief valve

    Taylor, W.L.


    This patent describes a pressure relief valve having a relief set pressure. It comprises: a valve body having a fluid inlet and outlet, a spherical, metal valve seat associated with the inlet and a valve member comprising at least a portion of a spherical,metal ball attached to a ball holding element, the valve member being biased against the valve seat and thus providing a metal-to-metal seal preventing the passage of fluids past the valve seat when the fluid pressure in the inlet is below the relief pressure setting of the valve.

  2. Vent Relief Valve Test


    Shown is the disassembly, examination, refurbishment and testing of the LH2 ( liquid hydrogen) and LOX (liquid oxygen) vent and relief valves for the S-IVB-211 engine stage in support of the Constellation/Ares project. This image is extracted from high definition video and is the highest resolution available.

  3. Pressure relief valve/safety relief valve testing

    Murray, W.A.; Hamm, E.R.; Barber, J.R.


    Pressure vessels and piping systems are protected form overpressurization by pressure relief valves. These safety features are required to be tested-inspected on some periodic basis and, in most cases witnessed by a third party inspector. As a result nonconformances found by third parties Westinghouse Hanford Company initiated a task team to develop a pressure safety program. This paper reveals their findings.

  4. Inexpensive tamper proof safety relief valve

    Frankewich, P. A.


    Basic relief valve has added safety relief valve capability that relieves overpressure before failure can occur. It may be installed in inaccesible areas with a high degree of reliability, constructed from a variety of materials, and adapted to the user's specific application.

  5. LOFT pressurizer safety: relief valve reliability

    Brown, E.S.


    The LOFT pressurizer self-actuating safety-relief valves are constructed to the present state-of-the-art and should have reliability equivalent to the valves in use on PWR plants in the U.S. There have been no NRC incident reports on valve failures to lift that would challenge the Technical Specification Safety Limit. Fourteen valves have been reported as lifting a few percentage points outside the +-1% Tech. Spec. surveillance tolerance (9 valves tested over and 5 valves tested under specification). There have been no incident reports on failures to reseat. The LOFT surveillance program for assuring reliability is equivalent to nuclear industry practice.

  6. Safety/relief-valve test program

    Hunter, J.A.


    In response to the NRC's Task 2.1.2 following the TMI-2 accident, government and industry programs were formulated to address the performance of safety and relief valve systems for pressurized and boiling water reactors. Objective is to demonstrate by testing and analysis that safety and relief valve systems in the reactor coolant system are qualified for the anticipated full range of reactor operating and accident conditions. The EPRI PWR program tested PWR safety valves and power operated relief valves (PORVs) under steam, liquid, and steam/liquid transition conditions. The program also tested PWR PORV block valves under steam conditions. The GE BWR program tested BWR relief and safety/relief valves under high pressure steam and low pressure liquid conditions. EG and G Idaho recent activities have focused on the evaluation of the industry test data, evaluation and modification of analytical codes for safety/relief valve system analysis, and initial evaluation of utility responses to US NRC program requirements.

  7. 46 CFR 154.806 - Capacity of pressure relief valves.


    ... 46 Shipping 5 2010-10-01 2010-10-01 false Capacity of pressure relief valves. 154.806 Section 154... Equipment Cargo Vent Systems § 154.806 Capacity of pressure relief valves. Pressure relief valves for each... pressure above the set pressure of the relief valves: (a) The maximum capacity of an installed cargo...

  8. Glovebox pressure relief and check valve

    Blaedel, K.L.


    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.

  9. Refuge alternatives relief valve testing and design.

    Lutz, T J; Bissert, P T; Homce, G T; Yonkey, J A


    The U.S. National Institute for Occupational Safety and Health (NIOSH) has been researching refuge alternatives (RAs) since 2007. RAs typically have built-in pressure relief valves (PRVs) to prevent the unit from reaching unsafe pressures. The U.S. Mine Safety and Health Administration requires that these valves vent the chamber at a maximum pressure of 1.25 kPa (0.18 psi, 5.0 in. H2O), or as specified by the manufacturer, above mine atmospheric pressure in the RA. To facilitate PRV testing, an instrumented benchtop test fixture was developed using an off-the-shelf centrifugal blower and ductwork. Relief pressures and flow characteristics were measured for three units: (1) a modified polyvinyl chloride check valve, (2) an off-the-shelf brass/cast-iron butterfly check valve and (3) a commercially available valve that was designed specifically for one manufacturer's steel prefabricated RAs and had been adapted for use in one mine operator's built-in-place RA. PRVs used in tent-style RAs were not investigated. The units were tested with different modifications and configurations in order to check compliance with Title 30 Code of Federal Regulations, or 30 CFR, regulations. The commercially available relief valve did not meet the 30 CFR relief pressure specification but may meet the manufacturer's specification. Alternative valve designs were modified to meet the 30 CFR relief pressure specification, but all valve designs will need further design research to examine survivability in the event of a 103 kPa (15.0 psi) impulse overpressure during a disaster.

  10. Mechanical Designs for Relief Valves for Cryogenic Apparatuses and Installations

    CERN. Geneva


    There are also pressure relief valves with warm seat available on which the set pressure is based on an adjustment of forces by permanent magnets. Pressure vessel rules allows also the choice for an active triggered pressure relief valve (Cont...

  11. 46 CFR 154.519 - Piping relief valves.


    ... 46 Shipping 5 2010-10-01 2010-10-01 false Piping relief valves. 154.519 Section 154.519 Shipping... Process Piping Systems § 154.519 Piping relief valves. (a) The liquid relief valve that protects the cargo piping system from liquid pressure exceeding the design pressure must discharge into: (1) A cargo...

  12. 46 CFR 98.25-60 - Safety relief valves.


    ... 46 Shipping 4 2010-10-01 2010-10-01 false Safety relief valves. 98.25-60 Section 98.25-60 Shipping... § 98.25-60 Safety relief valves. (a) Each tank shall be fitted with two or more approved safety relief valves, designed, constructed, and flow-tested for capacity in conformance with subpart 162.018...

  13. 46 CFR 154.1846 - Relief valves: Changing set pressure.


    ... 46 Shipping 5 2010-10-01 2010-10-01 false Relief valves: Changing set pressure. 154.1846 Section... Relief valves: Changing set pressure. The master shall: (a) Supervise the changing of the set pressure of relief valves under § 154.802(b); (b) Enter the change of set pressure in the vessel's log; and...

  14. PWR safety and relief valve test program. Valve selection/juftification report. Final report


    NUREG 0578 required that full-scale testing be performed on pressurizer safety valves and relief valves representative of those in use or planned for use in PWR plants. To obtain valve performance data for the entire population of PWR plant valves, nine safety valves and ten relief valves were selected as a fully representative set of test valves. Justification that the selected valves represent all PWR plant valves was provided by each safety and relief valve manufacturer. Both the valve selection and justification work was performed as part of the PWR Safety and Relief Valve Test Program conducted by EPRI on behalf of the PWR utilities in response to the recommendations of NUREG 0578 and the requirements of the NRC. Results of the Safety and Relief Valve Selection and Justification effort is documented in this report.

  15. Study of safety relief valve operation under ATWS conditions. [PWR

    Hutmacher, E.S.; Nesmith, B.J.; Brukiewa, J.B.


    A literature survey and analysis project has been performed to determine if recent (since mid-1975) data has been reported which could influence the current approach to predicting PWR relief valve capacity under ATWS conditions. This study was conducted by the Energy Technology Engineering Center for NRC. Results indicate that the current relief valve capacity model tends to predict less capacity than actually obtains; however, no experimental verification at PWR ATWS conditions was found. Other project objectives were to establish the availability of methods for evaluating reaction forces and back pressure effects on relief valve capacity, and to determine if facilities exist which are capable of testing PWR relief valves at ATWS conditions.

  16. Improved Relief Valve Would Be Less Susceptible to Failure

    Farner, Bruce R.


    The balanced-piston relief valve with side vented reaction cavity has been proposed as an improved alternative to a conventional high-pressure, high-flow relief valve. The proposed valve would be less susceptible to failure. A typical conventional high-pressure, high-flow relief valve contains a piston that is exposed to the upstream pressure across the full valve-seat diameter and is held against the valve seat and the upstream pressure by a large spring. In the event of an increase in upstream pressure to a level above the valve set point (the pressure above which the valve opens), the opening force on the piston can be so large that the piston becomes accelerated to a speed high enough that the ensuing hard impact of the piston within the valve housing results in failure of the valve. For a given flow cross section, the proposal would significantly reduce the force, thereby reducing susceptibility to failure. A basic version of the proposed balanced-piston relief valve with side vented reaction cavity is described.

  17. The development of safety relief valve for nuclear service

    Kim, Chil Sung; Kim, Kang Tae; Kim, Ji Heon; Jang, Ki Jong [Smart Valve Com., Seoul (Korea, Republic of); Hong, Kee Seong [Korea Hydro and Nuclear Power Co., Ltd., Seoul (Korea, Republic of)


    Safety relief valve is the important equipment used to protect the pressure facility from overpressure. The objective of the study is the development of safety relief valve which protects the boiler and pressure vessel from over pressure by discharging or sucking the operating medium when the pressure of system is reaching the set pressure of the system. It is important to find out the relationship between trim shape and performance, so the characteristics of flow field at the inside of safety relief valve were investigated through computational fluid dynamics analysis. The study shows that safety relief valve is developed though the design using the analysis between flow characteristics and spring force, the experiential verification.

  18. EPRI PWR Safety and Relief Value Test Program: safety and relief valve test report


    A safety and relief valve test program was conducted by EPRI for a group of participating PWR utilities to respond to the USNRC recommendations documented in NUREG 0578 Section 2.1.2, and as clarified in NUREG 0737 Item II.D.1.A. Seventeen safety and relief valves representative of those utilized in or planned for use in participating domestic PWR's were tested under the full range of selected test conditions. This report contains a listing of the selected test valves and the corresponding as tested test matrices, valve performance data and principal observations for the tested safety and relief valves. The information contained in this report may be used by the participating utilities in developing their response to the above mentioned USNRC recommendations.

  19. Rapidly design safety relief valve inlet piping systems

    Westman, M.A.


    Safety relief valves (SRVs) used to protect against overpressure require well-designed inlet piping for proper operation. The engineer`s job is to produce these designs from a thorough understanding of the inlet piping as a key component in the safety relief system and the correct application of the governing fluid dynamics principles. This article will present a technique for analysis and design using classical ideal-gas adiabatic fluid flow principles. Also, it will discuss the advantages of using the personal computer (PC) to quickly arrive at accurate designs. This work applies to SRVs in which relief flows are limited by sonic conditions at their nozzles.

  20. Emergency relief system design: The DIERS users group safety relief valve example problem

    Fisher, H.G. [Union Carbide Corp., South Charleston, WV (United States)


    Emergency relief system design involving two-phase flow is an evolving and complex technology. Aspects of alternative design techniques have been published. Well-documented, comprehensive design methods for safety relief valves, rupture disks and breather vents, however, are not readily available and example problems supported by data do not exist. Design Institute for Emergency Relief Systems (DIERS) Users Group members recently completed an example rating problem consisting of a safety relief valve mounted in a typical industrial configuration. Participants were asked to compute the flow through the device and to calculate the inlet pipe irreversible pressure loss and discharge pipe back pressure. Case studies involving various flows and physical conditions were formulated. A {open_quotes}Modified Delphi{close_quotes} technique was used to encourage participants to work until the {open_quotes}consensus{close_quotes} result was achieved. The exercise served to educate participants in the complexities and subtleties of emergency relief system design involving safety relief installations as compared to ideal nozzle calculations. All learned from the various calculation techniques used by others to solve the problem. Participants corrected parts of their computer codes and/or added procedures to address aspects of the problem. The present example problem is not supported by data. Available safety relief valve two-phase flow data suggest complexity not presently included in problem solutions. Future modification of the results may be required as additional considerations are incorporated into existing analytical methods and computer codes. 20 refs., 21 tabs.

  1. 49 CFR 230.49 - Setting of safety relief valves.


    ... ADMINISTRATION, DEPARTMENT OF TRANSPORTATION STEAM LOCOMOTIVE INSPECTION AND MAINTENANCE STANDARDS Boilers and... safety relief valves, two steam gauges shall be used, one of which must be so located that it will be in... varies more than 3 psi they shall be removed from the boiler, tested, and corrected before the...

  2. Presentation of the development of the SRV valve (safety relief valve); Presentation du developpement de la vanne SRV (Safety Relief Valve)

    Manguette, P. [Adareg, 59 - Haubourdin (France)


    Adareg has 30 years experience in Hydrane and control valves. Its know-how moves towards extreme technologies: control of all types of fluids (hot, cold, aggressive ones, clean ones etc... ). A perfect control is essential for very low temperatures (nuclear submarines, Ariane). Adareg Research and Development activities, certified ISO 9001, have developed valves accepting temperatures reaching 2 degrees above the absolute 0. Increasing requirements concerning low temperatures have encouraged Adareg to develop a research programme in partnership with CEA - French Atomic Energy Commission - for valves type 'SRV' (Safety Relief Valves). This type of valve is designed for a new accelerator of particles, the LHC, at CERN, in Geneva. (author)

  3. 49 CFR 179.220-24 - Tests of pressure relief valves.


    ... 49 Transportation 2 2010-10-01 2010-10-01 false Tests of pressure relief valves. 179.220-24 Section 179.220-24 Transportation Other Regulations Relating to Transportation PIPELINE AND HAZARDOUS...-24 Tests of pressure relief valves. Each safety relief valve must be tested by air or gas...

  4. 46 CFR 38.25-10 - Safety relief valves-TB/ALL.


    ... 46 Shipping 1 2010-10-01 2010-10-01 false Safety relief valves-TB/ALL. 38.25-10 Section 38.25-10... and Inspections § 38.25-10 Safety relief valves—TB/ALL. (a) The cargo tank safety relief valves shall be inspected at least once in every 2 years. (b) The safety relief valve discs must be lifted...

  5. Acoustic Resonance Frequency Elimination Device for Safety Relief Valves

    Redmond, J.


    Industry experience has shown that Safety Relief Valves (SRVs) and Steam Dryers installed in Boiling Water Reactors (BWRs) experience vibration induced degradation and failures caused by acoustic resonance vibration of the main steam lines, resulting in decreased reliability and potential safety issues. The resonance is caused by vortex shedding from the standpipe inlet and acoustic standing waves in the standpipe, occurring when the two frequencies match. (Author)

  6. PWR safety/relief valve blowdown analysis experience

    Lee, M.Z.; Chou, L.Y.; Yang, S.H. (Gilbert/Commonwealth Engineers and Consultants, Reading, PA (USA). Speciality Engineering Dept.)


    The paper describes the difficulties encountered in analyzing a PWR primary loop pressurizer safety relief valve and power operated relief valve discharge system, as well as their resolution. The experience is based on the use of RELAP5/MOD1 and TPIPE computer programs as the tools for fluid transient analysis and piping dynamic analysis, respectively. General approaches for generating forcing functions from thermal fluid analysis solution to be used in the dynamic analysis of piping are reviewed. The paper demonstrates that the 'acceleration or wave force' method may have numerical difficulties leading to unrealistic, large amplitude, highly oscillatory forcing functions in the vicinity of severe flow area discontinuities or choking junctions when low temperature loop seal water is discharged. To avoid this problem, an alternate computational method based on the direct force method may be used. The simplicity and superiority in numerical stability of the forcing function computation method as well as its drawbacks are discussed. Additionally, RELAP modeling for piping, valve, reducer, and sparger is discussed. The effects of loop seal temperature on SRV and PORV discharge line blowdown forces, pressure and temperature distributions are examined. Finally, the effects of including support stiffness and support eccentricity in piping analysis models, method and modeling relief tank connections, minimization of tank nozzle loads, use of damping factors, and selection of solution time steps are discussed.

  7. 49 CFR 179.100-19 - Tests of safety relief valves.


    ... 49 Transportation 2 2010-10-01 2010-10-01 false Tests of safety relief valves. 179.100-19 Section 179.100-19 Transportation Other Regulations Relating to Transportation PIPELINE AND HAZARDOUS...) § 179.100-19 Tests of safety relief valves. (a) Each valve shall be tested by air or gas for...

  8. 49 CFR 179.200-23 - Tests of pressure relief valves.


    ... 49 Transportation 2 2010-10-01 2010-10-01 false Tests of pressure relief valves. 179.200-23 Section 179.200-23 Transportation Other Regulations Relating to Transportation PIPELINE AND HAZARDOUS...-23 Tests of pressure relief valves. (a) Each valve shall be tested by air or gas for compliance...

  9. 49 CFR 179.400-21 - Test of pressure relief valves.


    ... 49 Transportation 2 2010-10-01 2010-10-01 false Test of pressure relief valves. 179.400-21 Section 179.400-21 Transportation Other Regulations Relating to Transportation PIPELINE AND HAZARDOUS...-113 and 107A) § 179.400-21 Test of pressure relief valves. Each valve must be tested with air or...

  10. The Design of Impact Test-Bed for High-Flow Water Medium Relief Valve

    Junliang Chang


    Full Text Available Water medium hydraulic systems are widely used in coal mining machinery. As the power of hydraulic system becomes higher, the flow and pressure of water medium relief valve are also higher, and the flow may reach 2000 L/min. However, there is no relevant test-bed which could provide instantaneous high-pressure and high-flow to support the experiment for high-flow relief valve; consequently, this impact test-bed for high-flow water medium relief valve is designed to satisfy fast loading demand. Through building model, simulation analysis, and construction of an impact test-bed of high-flow water medium relief valve, the dynamic performance of high-flow water medium relief valve is detected. The setting pressure of relief valve, the accumulator volume and the filling fluid pressure, and the damping of cartridge valve can be changed, and the dynamic performance of high-flow water medium relief valve under different impact loads is detected. The results show that the designed impact test-bed of high-flow water medium relief valve could provide required high-pressure and high-flow emulsion for the tested water medium relief valve, and it could control the strength of impact load, which is an energy saving, high efficiency, and low cost method.

  11. Study on hydraulic direct-acting relief valve

    Syrkin, V. V.; Balakin, P. D.; Treyer, V. A.


    Valves with elastic shut-off-and-regulating elements are increasingly applied in hydraulic systems, working in conditions of excessive vibrations. The objective of this study is to determine the dynamic characteristics of regulators with shut-off-and- regulating elements. The method of phase trajectories establishes the controller’s parameters and modes, which provide its work stability. The authors receive dynamic characteristics providing the absence of self-oscillations at the expense of additional damping of the shut-off- and-regulating element. They make a test sample of the pressure regulator with an elastic shut-off-and-regulating element. The article defines the characteristics curve of the pressure regulator (direct operated pressure relief valve) from the initial conditions. The obtained results can be used, when designing hydraulic technological machines. Keywords - oscillation damping, an elastic shut-off-and regulating element.

  12. Summary of safety relief valve position indication systems

    Cybulski, D.S.; Walter, J.F.


    Mainly as a result of the Three Mile Island-2 (TMI-2) incident, the US Nuclear Regulatory Commission's Regulatory Guide 1.97 instituted criteria recommendations for monitoring variables to: 1. provide information required to permit the operator to take preplanned manual actions to accomplish safe plant shutdown; 2. determine important to safety are performing their functions...; and 3. provide information to the operators that will enable them to determine the potential for causing a gross breach of the barriers to radioactivity release.... This report surveys the methodologies employed in nuclear plants to monitor Type D variables as referred to in Regulatory Guide 1.97. Type D are those variables that provide information to indicate the operation of individual safety systems and other systems important to safety. The specific Type D variable addressed is safety relief valve (i.e., spring style safety relief valve) position indication. The application criteria for each of the methodologies surveyed is as described in Regulatory Guide 1.97. That is, minimally to provide light indications of closed/not closed positions.

  13. 46 CFR 58.16-15 - Valves and safety relief devices.


    ... 46 Shipping 2 2010-10-01 2010-10-01 false Valves and safety relief devices. 58.16-15 Section 58.16... AUXILIARY MACHINERY AND RELATED SYSTEMS Liquefied Petroleum Gases for Cooking and Heating § 58.16-15 Valves and safety relief devices. (a) Each cylinder shall have a manually operated screw-down shutoff...

  14. 46 CFR 38.10-15 - Safety relief valves-TB/ALL.


    ... 46 Shipping 1 2010-10-01 2010-10-01 false Safety relief valves-TB/ALL. 38.10-15 Section 38.10-15 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY TANK VESSELS LIQUEFIED FLAMMABLE GASES Piping, Valves, Fittings, and Accessory Equipment § 38.10-15 Safety relief valves—TB/ALL. (a) Each tank shall be...

  15. 77 FR 59408 - Finding of Equivalence; Alternate Pressure Relief Valve Settings on Certain Vessels Carrying...


    ... SECURITY Coast Guard Finding of Equivalence; Alternate Pressure Relief Valve Settings on Certain Vessels... Coast Guard announces the availability of CG-ENG Policy Letter 04-12, ``Alternative Pressure Relief Valve Settings on Vessels Carrying Liquefied Gases in Bulk in Independent Type B and Type C...

  16. 46 CFR 56.50-25 - Safety and relief valve escape piping.


    ... 46 Shipping 2 2010-10-01 2010-10-01 false Safety and relief valve escape piping. 56.50-25 Section 56.50-25 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) MARINE ENGINEERING PIPING SYSTEMS AND APPURTENANCES Design Requirements Pertaining to Specific Systems § 56.50-25 Safety and relief valve escape piping. (a) Escape piping...

  17. Specifications and Performances of Series Superfluid Helium Safety Relief Valves for the LHC

    Perin, A.; Fontanive, V.


    Protecting the LHC magnets requires safety relief valves operating with 1.9 K pressurized superfluid helium at their inlet. Following the evaluation of prototype valves, a specification for the production of the 360 safety relief valves needed for the LHC was issued. The production of the safety valves was then awarded to an industrial contractor. The performances of pre-series valves were assessed for a variety of aspects including thermal performance, leak tightness in superfluid helium, dynamic behavior and resistance to intensive mechanical cycling. After the initial validation phase the series production was completed within the technical requirements of the specification. This paper describes the characteristics of the safety relief valves and the specifications for their industrial production. The performances of the pre-series valves are presented and an overview of the series production phase is given.

  18. Development of the large main steam safety relief valve

    Takeshima, Kikuo [Hitachi Ltd., Tokyo (Japan); Takasaki, Kiyoshi; Hamada, Nobuyoshi


    In order to control rise of reactor pressure at formation of over-pressure transition accident in a boiling water (BWR) type nuclear power plant, the numbers of the main steam safety relief valve (MSSRV) installed in a storage vessel increases with out-put in the plant, and for 1.35 MkW class improved BWR (ABWR) 18 sets of MSSRV are installed. And, in an ABWR preparing of construction at Ohma-cho, Aomori prefecture by the Electric Power Development Co., Ltd., uranium-plutonium mixed oxides (MOX) fuel is planned to load, to tend to further increase required numbers of MSSRV. In order to control arrangement in a storage vessel and increase of conservative inspection work together with increase the required numbers of MSSRV, it was planned to develop a large volume of MSSRV (16% increase in volume on comparison with that of conventional one), to confirm its function and feature by its testing and to apply to an actual machine. Here was introduced on its developmental contents and testing results. As a result, it could be estimated that required numbers of MSSRV would be sixteen, and was confirmed that features such as correlation on flowing-out pressure between nitrogen and steam, durability, work stability, valve seat leakage resistance, and so forth were similar to those of present MSSRV. (G.K.)

  19. Valve inlet fluid conditions for pressurizer safety and relief valves in combustion engineering-designed plants. Final report. [PWR

    Bahr, J.; Chari, D.; Puchir, M.; Weismantel, S.


    The purpose of this study is to assemble documented information for C-E designed plants concerning pressurizer safety and power operated relief valve (PROV) inlet fluid conditions during actuation as calculated by conventional licensing analyses. This information is to be used to assist in the justification of the valve inlet fluid conditions selected for the testing of safety valves and PORVs in the EPRI/PWR Safety/Relief Valve Test Program. Available FSAR/Reload analyses and certain low temperature overpressurization analyses were reviewed to identify the pressurization transients which would actuate the valves, and the corresponding valve inlet fluid conditions. In addition, consideration was given to the Extended High Pressure Liquid Injection event. A general description of each pressurization transient is provided. The specific fluid conditions identified and tabulated for each C-E designed plant for each transient are peak pressurizer pressure, pressure ramp rate at actuation, temperature and fluid state.

  20. Investigation Of Adhesion Formation In New Stainless Steel Trim Spring Operated Pressure Relief Valves

    Gross, Robert E. [Savannah River Site (SRS), Aiken, SC (United States); Bukowski, Julia V. [Villanova University, Villanova, PA (United States); Goble, William M. [exida, Sellersville, PA (United States)


    Examination of proof test data for new (not previously installed) stainless steel (SS) trim spring operated pressure relief valves (SOPRV) reveals that adhesions form between the seat and disc in about 46% of all such SOPRV. The forces needed to overcome these adhesions can be sufficiently large to cause the SOPRV to fail its proof test (FPT) prior to installation. Furthermore, a significant percentage of SOPRV which are found to FPT are also found to ''fail to open'' (FTO) meaning they would not relief excess pressure in the event of an overpressure event. The cases where adhesions result in FTO or FPT appear to be confined to SOPRV with diameters < 1 in and set pressures < 150 psig and the FTO are estimated to occur in 0.31% to 2.00% of this subpopulation of SS trim SOPRV. The reliability and safety implications of these finding for end-users who do not perform pre-installation testing of SOPRV are discussed.

  1. Resolving plant operational issues related to pressurizer safety relief valve piping

    Bain, R.A. [Stone and Webster Engineering Corp., Boston, MA (United States). Mechanical Engineering Div.; Testa, M.F. [Duquesne Light Co., Shippingport, PA (United States). Mechanical Engineering Dept.


    Pressurizer safety and relief valve (PSARV) piping has many technical issues related to the qualification and operation of the system that have been addressed at Beaver Valley Unit 2. The PSARV piping is part of a system that must meet Code requirements while being subjected to very significant fluid transient loadings. Valve components include safety valves, power operated relief valves (PORVs), and motor operated block valves. Fluid slugs upstream of these valves can be steam or can be hot or cold water, resulting in a significant variance in possible slug densities. Problems with design options and hardware installed to decrease slug density such as heat tracing, and the susceptibility of the PORVs to leak are issues that affect plant operation, efficiency and cost effectiveness.

  2. EPRI PWR Safety and Relief Valve Test Program: test condition justification report

    Hosler, J.


    In response to NUREG 0737, Item II.D.1.A requirements, several safety and relief valve designs were tested by EPRI under PWR utility sponsorship. Justification that the inlet fluid conditions under which these valve designs were tested are representative of those expected in participating domestic PWR units during FSAR, Extended High Pressure Injection, and Cold Overpressurization events is presented.

  3. 46 CFR 54.15-10 - Safety and relief valves (modifies UG-126).


    ... reference; see 46 CFR 54.01-1). (f) Cast iron may be employed in the construction of relief valves for... with CGA S-1.2 (incorporated by reference; see 46 CFR 54.01-1). (2) 110 percent of the valve...

  4. Valve inlet fluid conditions for pressurizer safety and relief valves in Westinghouse-designed plants. Final report. [PWR

    Meliksetian, A.; Sklencar, A.M.


    The overpressure transients for Westinghouse-designed NSSSs are reviewed to determine the fluid conditions at the inlet to the PORV and safety valves. The transients considered are: licensing (FSAR) transients; extended operation of high pressure safety injection system; and cold overpressurization. The results of this review, presented in the form of tables and graphs, define the range of fluid conditions expected at the inlet to pressurized safety and power-operated relief valves utilized in Westinghouse-designed PWR units. These results will provide input to the PWR utilities in their justification that the fluid conditions under which their valve designs were tested as part of the EPRI/PWR Safety and Relief Valve Test Program indeed envelop those expected in their units.


    Gross, Robert; Harris, Stephen


    Proof test results were analyzed and compared with a proposed life cycle curve or hazard function and the limit of useful life. Relief valve proof testing procedures, statistical modeling, data collection processes, and time-in-service trends are presented. The resulting analysis of test data allows for the estimation of the PFD. Extended maintenance intervals to the limit of useful life as well as methodologies and practices for improving relief valve performance and reliability are discussed. A generic cost-benefit analysis and an expected life cycle cost reduction concludes that $90 million maintenance dollars might be avoided for a population of 3000 valves over 20 years.

  6. Transient analysis of water slug discharge in PWR safety/relief valve piping. [WATSLUG code

    Van Duyne, D.A.; Hsieh, J.S.; Shave, D.F.


    The sudden discharge of the water loop seal, which is often present upsteam of pressurizer safety and relief valves, creates large momentum and inertia forces on the piping segments downstream of the valve. This paper provides a brief discussion of the commonly available control-volume calculation techniques, a description of the governing equations and a recently developed computer routine (WATSLUG) for their solution, and a review of results calculated using this method for a typical pressurizer safety and relief valve system. 8 refs.

  7. Processing techniques for data from the Kuosheng Unit 1 shakedown safety-relief-valve tests

    McCauley, E.W.; Rompel, S.L.; Weaver, H.J.; Altenbach, T.J.


    This report describes techniques developed at the Lawrence Livermore National Laobratory, Livermore, CA for processing original data from the Taiwan Power Company's Kuosheng MKIII Unit 1 Safety Relief Valve Shakedown Tests conducted in April/May 1981. The computer codes used, TPSORT, TPPLOT, and TPPSD, form a special evaluation system for treating the data from its original packed binary form to ordered, calibrated ASCII transducer files and then to production of time-history plots, numerical output files, and spectral analyses. Using the data processing techniques described, a convenient means of independently examining and analyzing a unique data base for steam condensation phenomena in the MARKIII wetwell is described. The techniques developed for handling these data are applicable to the treatment of similar, but perhaps differently structured, experiment data sets.


    Harris, S.; Gross, R.


    The safety integrity level (SIL) of equipment used in safety instrumented functions is determined by the average probability of failure on demand (PFDavg) computed at the time of periodic inspection and maintenance, i.e., the time of proof testing. The computation of PFDavg is generally based solely on predictions or estimates of the assumed constant failure rate of the equipment. However, PFDavg is also affected by maintenance actions (or lack thereof) taken by the end user. This paper shows how maintenance actions can affect the PFDavg of spring operated pressure relief valves (SOPRV) and how these maintenance actions may be accounted for in the computation of the PFDavg metric. The method provides a means for quantifying the effects of changes in maintenance practices and shows how these changes impact plant safety.

  9. Study of safety relief valve operation under ATWS conditions. [Supercritical flow

    Hutmacher, E.S.; Whitten, S.D.


    In March 1979, the NRC published a report (NUREG/CR-0687) prepared by the Energy Technology Engineering Center (ETEC-TDR-78-19). That report presented a literature survey which updated earlier NRC studies of saturated or subcooled water flow through relief valves, under ATWS conditions. This supplement expands upon that search to include supercritical steam-water flow. No applicable data for the supercritical conditions were found, nor were any newer data on saturated or subcooled conditions uncovered. This supplement also updates a look for facilities currently capable of simultaneously imposing all ATWS conditions upon test relief valves. Results confirmed the negative findings of NUREG/CR-0687.

  10. Study of safety relief valve operation under ATWS conditions. [Super critical flow

    Hutmacher, E.S.; Whitten, S.D.


    In March 1979, ETEC published as ETEC-TDR-78-19 a search which updated earlier NRC studies of saturated or subcooled water flow through relief valves, under ATWS conditions. This Supplement expands upon that search to include supercritical steam-water flow. No applicable data for the supercritical conditions was found, nor were any newer data on saturated or subcooled conditions uncovered. The Supplement also updated a look for facilities currently capable of simultaneously imposing all ATWS conditions upon test relief valves. Results confirmed the negative findings of ETEC-TDR-78.19.

  11. Assessment of SWBR safety-relief valve discharge line dynamic loads due to steam blowdown

    Spoelstra, S.; Stoop, P.M. [Netherlands Energy Research Foundation (ECN), Petten (Netherlands); Dijk, A.B. van [Stork Nucon BV (Netherlands)


    The Safety/Relief Valve Discharge Lines of the SBWR nuclear power plant are subject to dynamic loads due to steam blowdown after rapid opening of the Safety/Relief Valves. This paper describes the calculation of the thermal-hydraulic loads exerted on the piping system and the calculation of the resulting pipe stresses. These calculations have been performed using the CHARME and PS+CAEPIPE computer programs respectively. The calculated pipe stresses have been combined with the ones resulting from dead weight and thermal expansion and compared with ASME III criteria. (orig.).


    Gao Hong; Lin Wanlai; Fu Xin; Yang Huayong; Tsukiji Tetsuhiro


    The aim of this study is to suppress a cavitation near the orifice of a relief valve by changing the shape of a poppet. An experimental flow visualization technique and a numerical cavitating flow simulation, using a RNG k-ε turbulence model and a cavitation model, are employed to achieve the purpose. In the flow visualization, the cavitation phenomenon near the orifice of a relief valve is observed using a transparent test valve body model and a camera. On the other hand, a three dimensional cavitating flow simulation is conducted to predict the cavitation near the orifice of a relief valve.Six types of poppets are designed by changing the shape of a traditional poppet shape, which is expected to influence the cavitating flow in an orifice. In addition, the cavitation noise of a relief valve is measured and the noise spectrum is analyzed. In conclusion, the cavitation intensity and the cavitation noise are reduced for an optimal poppet geometry obtained in the present study.

  13. 46 CFR 53.05-2 - Relief valve requirements for hot water boilers (modifies HG-400.2).


    ... 46 Shipping 2 2010-10-01 2010-10-01 false Relief valve requirements for hot water boilers... requirements for hot water boilers (modifies HG-400.2). (a) The relief valve requirements for hot water boilers... (incorporated by reference; see 46 CFR 53.01-1) except as noted otherwise in this section. (b) Hot water...

  14. Review of the development of safety and relief valve silencers for steam discharge

    Crawford, C.J.


    The progress made by the Central Electricity Generating Board (CEGB) in the development of silencers for the control of boiler safety valve and relief valve noise is reviewed. System noise sources and the formulation of environmental noise criteria are discussed; the silencer design philosophy adopted by the CEGB is described and the progressive improvements are charted to demonstrate the advances made over earlier practices. The results of this work are design concepts which provide silencers which are suitable for application to any of the CEGB's steam valve vent systems and are capable of meeting stringent neighbourhood noise criteria.

  15. Examples, clarifications, and guidance on preparing requests for relief from pump and valve inservice testing requirements

    Ransom, C.B.; Hartley, R.S. [Lockheed Idaho Technologies Co., Idaho Falls, ID (United States)


    In this report, the Idaho National Engineering Laboratory reviewers discuss related to requests for relief from the American Society of Mechanical Engineers code requirements for inservice testing (IST) of safety-related pumps and valves at commercial nuclear power plants. This report compiles information and examples that may be useful to licensees in developing relief requests submitted to US Nuclear Regulatory Commission (NRC) for their consideration and provides insights and recommendations on related IST issues. The report also gives specific guidance on relief requests acceptable and not acceptable to the NRC and advises licensees in the use of this information for application at their facilities.

  16. The safety relief valve handbook design and use of process safety valves to ASME and International codes and standards

    Hellemans, Marc


    The Safety Valve Handbook is a professional reference for design, process, instrumentation, plant and maintenance engineers who work with fluid flow and transportation systems in the process industries, which covers the chemical, oil and gas, water, paper and pulp, food and bio products and energy sectors. It meets the need of engineers who have responsibilities for specifying, installing, inspecting or maintaining safety valves and flow control systems. It will also be an important reference for process safety and loss prevention engineers, environmental engineers, and plant and process designers who need to understand the operation of safety valves in a wider equipment or plant design context. . No other publication is dedicated to safety valves or to the extensive codes and standards that govern their installation and use. A single source means users save time in searching for specific information about safety valves. . The Safety Valve Handbook contains all of the vital technical and standards informat...

  17. Recent performance experience with US light water reactor self-actuating safety and relief valves

    Hammer, C.G.


    Over the past several years, there have been a number of operating reactor events involving performance of primary and secondary safety and relief valves in U.S. Light Water Reactors. There are several different types of safety and relief valves installed for overpressure protection of various safety systems throughout a typical nuclear power plant. The following discussion is limited to those valves in the reactor coolant systems (RCS) and main steam systems of pressurized water reactors (PWR) and in the RCS of boiling water reactors (BWR), all of which are self-actuating having a setpoint controlled by a spring-loaded disk acting against system fluid pressure. The following discussion relates some of the significant recent experience involving operating reactor events or various testing data. Some of the more unusual and interesting operating events or test data involving some of these designs are included, in addition to some involving a number of similar events and those which have generic applicability.

  18. The optimum design of the pressure control spring of the relief valve based on neural networks

    FU Xiao-jin


    Based on the traditional optimization methods about the pressure control spring of the relief valve and combined with the advantages of neural network, this paper put forward the optimization method with many parameters and a lot of constraints based on neural network. The object function of optimization is transformed into the energy function of the neural network and the mathematical model of neural network optimization about the pressure control spring of the relief valve is set up in this method which also puts forward its own algorithm. An example of application shows that network convergence gets stable state of minimization object function E, and object function converges to the utmost minimum point with steady function, then best solution is gained, which makes the design plan better. The algorithm of solution for the problem is effective about the optimum design of the pressure control spring and improves the performance target.

  19. Water hammer, flow induced vibration and safety/relief valve loads

    Valandani, P.; Uffer, R.; Sexton, D.


    This report presents the results of an evaluation performed to determine current and recommended practices regarding the consideration of water hammer, flow-induced vibration and safety-relief valve loads in the design of nuclear power plant piping systems. Current practices were determined by a survey of industry experts. Recommended practices were determined by evaluating factors such as load magnitude and frequency content, system susceptibility to load occurrence and safety effects of postulated piping damage.

  20. In-plant safety/relief valve discharge load test, Monticello Plant. Final report

    Buzek, E.A. (comp.)


    This document reports the results of the test program of safety/relief valve (SRV) discharge load phenomena through a ramshead discharge device, and the effects upon the Mark I primary containment torus structure of the Monticello Nuclear Power Plant. The objectives were to provide a data base for verifying/improving bubble pressure, water reflood and piping load analytical models, and to measure the structural response of the torus, SRV piping, supports and acceleration of the basement and pedestal.

  1. Experimental Investigation of Cavitation in a Safety Relief Valve using water. Extension to Cryogenic fluids.

    Pinho, Jorge


    This thesis addresses the experimental investigation of the cavitation phenomenon and its main consequences on the normal operation of a safety relief valve (SRV). More particularly, limitation of the mass flux discharged and alteration of the hydraulic fluid forces behavior is of main interest for the proper design and sizing of such devices. In nuclear or thermal engineering systems, the use of SRVs is mandatory since it represents the ultimate protection device before an accident occurs, c...

  2. Safety relief valves according new requirements of EN (PED) versus AD/TRD or ASME

    Foellmer, B.; Schnettler, A. [Bopp and Reuther, Mannheim (Germany)


    In Europe, only Pressure safety relief valves which conform with the Pressure Equipment Directive (PED) 97/23 EC may be used. They are classified PED Category IV and a Notified Body validates the fulfilment of the PED requirements in accordance with a selected conformity evaluation procedure also drawn from PED. The harmonized standards or other technical reference works are stated in a manufacturer's declaration of conformity, which is supplied with the safety relief valve at delivery. Only this ultimately makes it possible to establish the basis used for CE certification and the certified properties which can be derived there from. The CE symbol in the identification plate alone does not supply sufficient information for this purpose. A comparative assessment of the harmonized EN standards compared against the AD and TRD technical rules in this article discloses differences in the certified properties and the applications for spring-loaded safety relief valves. The ASME code is also included in the assessment, since it plays a significant role at least outside Europe. (orig.)

  3. Valve inlet fluid conditions for pressurizer safety and relief valves for B and W 177-FA and 205-FA plants. Final report. [PWR

    Cartin, L.R.; Winks, R.W.; Merchent, J.W.; Brandt, R.T.


    The overpressurization transients for the Babcock and Wilcox Company's 177- and 205-FA units are reviewed to determine the range of fluid conditions expected at the inlet of pressurizer safety and relief valves. The final Safety Analysis Report, extended high-pressure injection, and cold overpressurization events are considered. The results of this review, presented in the form of tables and graphs, provide input to the PWR utilities in their justification that the fluid conditions under which their valve designs were tested as part of the EPRI PWR Safety and Relief Valve Test Program are representative of those expected in their unit(s).

  4. Assessment study of RELAP5/MOD2 Cycle 36. 04 based on pressurizer safety and relief valve tests

    Stubbe, E.J.; Vanhoenacker, L.


    This report presents a code assessment study based on full size relief and assisted safety valve (called SEBIM) tests performed on the CUMULUS valve test rig operated by Electricite de France (EdF). The increased awareness that the pressuriser safety and relief valves are not reliable under water blowdown conditions, has led to the design, testing and installation of so called assisted safety valves of which the SEBIM (TM) valves are an example. These valves, used in tandem, are gradually replacing the safety and relief valves on pressurisers in some European PWR's. Before installation at the plant, the Belgian safety authorities requested a thorough full scale testing of these valves on a test rig (CUMULUS) equipped with sufficient diagnostics to measure the characteristics of the valve. The Belgian architect-engineering firm TRACTEBEL was called upon the specify, order and test these valves for installation at the DOEL 1 and DOEL 2 power plants. These tests do provide sufficient data of high quality to justify an assessment study of the code RELAP-5 MOD-2 CYCLE 36 in the ICAP framework which is the subject of this report.

  5. The optimization of design parameters for surge relief valve for pipeline systems

    Kim, Hyunjun; Hur, Jisung; Kim, Sanghyun


    Surge is an abnormal pressure which induced by rapid changes of flow rate in pipeline systems. In order to protect pipeline system from the surge pressure, various hydraulic devices have been developed. Surge-relief valve(SRV) is one of the widely applied devices to control surge due to its feasibility in application, efficiency and cost-effectiveness. SRV is designed to automatically open under abnormal pressure and discharge the flow and makes pressure of the system drop to the allowable level. The performance of the SRV is influenced by hydraulics. According to previous studies, there are several affecting factors which determine performance of the PRV such as design parameters (e.g. size of the valve), system parameters (e.g. number of the valves and location of the valve), and operation parameters (e.g. set point and operation time). Therefore, the systematic consideration for factors affecting performance of SRV is required for the proper installation of SRV in the system. In this study, methodology for finding optimum parameters of the SRV is explored through the integration of Genetic Algorithm(GA) into surge analysis.

  6. Safety relief valve instabilities; Instabiles Verhalten beim Betrieb von direkt belasteten Sicherheitsventilen

    Neuhaus, Thorsten; Bloemeling, Frank; Jung, Andreas; Schaffrath, Andreas [TUeV NORD SysTec GmbH und Co. KG, Hamburg (Germany)


    The opening and closing of safety relief valves induce pressure vibrations and respective loads on the piping system. The quantification of the internal pressure load and the pipe segment forces for the proof of the structural integrity of the piping system and the supports is performed using the code DYVRO. It is not clear whether the calculated result of high-frequent opening and closing shows a realistic behavior or is caused by a simplified modeling. The contribution offers strategic recommendations to avoid unrealistic calculations.

  7. Guidelines for confirmatory inplant tests of safety-relief valve discharges for BWR plants

    Su, T.M.


    Inplant tests of safety/relief valve (SRV) discharges may be required to confirm generically established specifications for SRV loads and the maximum suppression pool temperature, and to evaluate possible effects of plant-unique parameters. These tests are required in those plants which have features that differ substantially from those previously tested. Guidelines for formulating appropriate test matrices, establishing test procedures, selecting necessary instrumentation, and reporting the test results are provided in this report. Guidelines to determine if inplant tests are required on the basis of the plant unique parameters are also included in the report.

  8. Mark II containment, supporting program report. Ramshead safety/relief valve loads methodology summary. [BWR

    Anderson, G.L.


    An overview of information describing and supporting the analytical methods for determining loads associated with safety/relief valve discharge to the suppression pool of the Mark II containment lead plants is presented. SRV discharge phenomena and associated loads, analytical methods for calculating these loads, supporting experimental information, application of the methods to lead plant assessment, and supporting programs are summarily described. The report demonstrates that, with regard to SRV discharge loads on the containment, an adequate technical basis exists for permitting the licensing assessment of the Mark II lead plants to continue on schedule.

  9. Preliminary planning study for safety relief valve experiments in a Mark III BWR pressure suppression system

    McCauley, E.W.; Holman, G.S.


    In response to a request from the Water Reactor Safety Research Division of the US NRC, a preliminary study is provided which identifies key features and consideration involved in planning a comprehensive in-plant Safety Relief Valve experimental program for a Mark III containment design. The report provides identification of program objectives, measurement system requirements, and some details quantifying expected system response. In addition, a preliminary test matrix is outlined which involves a supporting philosophy intended to enhance the usefulness of the experimental results for all members of the program team: experimentalists, analysts, and plant operator.

  10. Preliminary report: in-plant safety/relief valve discharge load test, Monticello Plant

    Chang, H.C. (comp.)


    This preliminary report covers the results of the test program of safety/relief valve (SRV) discharge load phenomena and the effects upon the Mark I primary containment torus structure of the Monticello Nuclear Power Plant. The objectives of the test were to provide a data base for verifying/improving analytical models and to measure the structural response of the torus to SRV discharges. Objectives, instrumentation, and test plan are described. Results of continuing data evaluation will be included in the final report scheduled for publication later in 1977.

  11. CCF analysis of high redundancy systems safety/relief valve data analysis and reference BWR application. Main report

    Mankamo, T. [Avaplan Oy (Finland); Bjoere, S.; Olsson, Lena [ABB Atom AB, Vaesteraas (Sweden)


    Dependent failure analysis and modeling were developed for high redundancy systems. The study included a comprehensive data analysis of safety and relief valves at the Finnish and Swedish BWR plants, resulting in improved understanding of Common Cause Failure mechanisms in these components. The reference application on the Forsmark 1/2 reactor relief system, constituting of twelve safety/relief lines and two regulating relief lines, covered different safety criteria cases of reactor depressurization and overpressure protection function, and failure to re close sequences. For the quantification of dependencies, the Alpha Factor Model, the Binomial Probability Model and the Common Load Model were compared for applicability in high redundancy systems.

  12. Safety/relief valve quencher loads: evaluation for BWR Mark II and III containments

    Su, T.M.


    Boiling water reactor (BWR) plants are equipped with safety/relief valves (SRVs) to protect the reactor from overpressurization. Plant operational transients, such as turbine trips, will actuate the SRV. Once the SRV opens, the air column within the partially submerged discharge line is compressed by the high-pressure steam released from the reactor. The compressed air discharged into the suppression pool produces high-pressure bubbles. Oscillatory expansion and contraction of these bubbles create hydrodynamic loads on the containment structures, piping, and equipment inside containment. This report presents the results of the staff's evaluation of SRV loads. The evaluation, however, is limited to the quencher devices used in Mark II and III containments. With respect to Mark I containments, the SRV acceptance criteria are presented in NUREG-0661 issued July 1980. The staff acceptance criteria for SRV loads for Mark II and III containments are presented in this report.

  13. State-of-the-Art Report on Pilot Operated Safety Relief Valve

    Lee, Jun; Yoon, Ju Hyeon


    The pilot operated safety relief valve(POSRV) is a overpressure protection device. But the POSRV is additionally designed to be functioned as a fast depressurization device differently from the pressurizer safety valve(PSV). So, the POSRV assembly takes on the complicated configuration differently from the PSV, and also its configuration and component parts are much different according to its manufacturers. The objective of the study is to investigate the state of the art for POSRV. We want that the findings of the study are put to practical use as a selection guide to the utilities or system designers which want to purchase the POSRV. In this study, we selected the SEBIM and CCI made goods as the subject of investigation, and have investigated the technical characteristics and operating principles of the goods. However, in this report, the comparative contents with other company which were issued by one company were not handled. Also the advantages or disadvantages between two companies were not handled. Only the technical characteristics and operating principles with each company were described. For reference, the main considerations to select the POSRV' type are follows. - the characteristics of the system that the POSRV is to be installed - the fitness of the POSRV for the system - the requirements related to the function and operation of the POSRV - the vender's opinion.

  14. Development of large capacity main steam safety relief valve in BWR

    Hama, Teruo; Takasaki, Kiyoshi [Electric Power Development Co. Ltd., Tokyo (Japan); Takeshima, Kikuo; Hamada, Nobuyoshi


    As a change of reactor performance on design of an improved type boiling water reactor aiming at loading of uranium-plutonium mixed oxides fuel (MOX fuel) at Oma town in Aomori prefecture, negative absolute value in void coefficient has an increasing trend due to loading of the MOX fuel. As a result, pressure increase in reactor pressure vessel has increasing trend at forming of pressurized transient phenomenon such as negative loading loss, and then it was attempted to increase total flushing amount of a main stream safety relief valve (MSSRV) for its relaxation. Then, in order to control increase of setting numbers of the valve, relax limitation of arrangement of its storing vessel, and control increase of maintenance and inspection works, a large capacity MSSRV of 460 t/h with about 16% larger flushing amount than that of present MSSRV was planned to an actual reactor. As a result, it could be confirmed by its functional tests and so forth that it had nearly equal correlation of flushing pressure on nitrogen and steam to that of the present MSSRV, nearly same reliability on enough durability, good working stability, and so forth as that of the present MSSRV, and no obstacle on its application to an actual reactor. (G.K.)

  15. Analysis of pressure oscillations and safety relief valve vibrations in the main steam system of a Boiling Water Reactor

    Galbally, David, E-mail: [Innomerics, Calle San Juan de la Cruz 2, 28223 Madrid (Spain); García, Gonzalo [Alava Ingenieros, Calle Albasanz 16, 28037 Madrid (Spain); Hernando, Jesús; Sánchez, Juan de Dios [Iberdrola, Calle Tomás Redondo 1, 28033 Madrid (Spain); Barral, Marcos [Alava Ingenieros, Calle Albasanz 16, 28037 Madrid (Spain)


    Highlights: • We analyze the vibratory response of safety relief valves in the main steam system of a Boiling Water Reactor. • We show that valve internals experience acceleration spikes of more than 20 g. • Spikes are caused by impacts between the valve disc and the seating surface of the valve nozzle. • Resonances occur at higher Strouhal numbers than those reported in the literature for tandem side branches. • Valves experience high vibration levels even for resonances caused by second order hydrodynamic modes. - Abstract: Steam flow inside the main steam lines of a Boiling Water Reactor can generate high-amplitude pressure oscillations due to coupling between the separated shear layer at the mouth of the safety relief valves (SRVs) and the acoustic modes of the side branches where the SRVs are mounted. It is known that certain combinations of flow velocities and main steam line geometries are capable of generating self-excited pressure oscillations with very high amplitudes, which can endanger the structural integrity of main steam system components, such as safety valves, or reactor internals such as steam dryers. However, main steam systems may also experience lower amplitude pressure oscillations due, for example, to coupling of higher order hydrodynamic modes with acoustic cavity modes, or to incipient resonances where the free stream velocity is slightly lower than the critical flow velocity required to develop a stable locked-on acoustic resonance. The amplitude of these pressure oscillations is typically insufficient to cause readily observable structural damage to main steam system components, but may still have subtle effects on safety relief valves. The investigation presented in this article focuses on the characterization of the response of SRVs under the effects of pressure oscillations associated with acoustic excitations that are insufficient to cause structural damage to the valves or associated equipment. It is shown that valve


    Gross, R; Stephen Harris, S


    The Savannah River Site operates a Relief Valve Repair Shop certified by the National Board of Pressure Vessel Inspectors to NB-23, The National Board Inspection Code. Local maintenance forces perform inspection, testing, and repair of approximately 1200 spring-operated relief valves (SORV) each year as the valves are cycled in from the field. The Site now has over 7000 certified test records in the Computerized Maintenance Management System (CMMS); a summary of that data is presented in this paper. In previous papers, several statistical techniques were used to investigate failure on demand and failure rates including a quantal response method for predicting the failure probability as a function of time in service. The non-conservative failure mode for SORV is commonly termed 'stuck shut'; industry defined as the valve opening at greater than or equal to 1.5 times the cold set pressure. Actual time to failure is typically not known, only that failure occurred some time since the last proof test (censored data). This paper attempts to validate the assumptions underlying the statistical lifetime prediction results using Monte Carlo simulation. It employs an aging model for lift pressure as a function of set pressure, valve manufacturer, and a time-related aging effect. This paper attempts to answer two questions: (1) what is the predicted failure rate over the chosen maintenance/ inspection interval; and do we understand aging sufficient enough to estimate risk when basing proof test intervals on proof test results?

  17. Design of Pressure Relief Valves for Protection of Steel-Lined Pressure Shafts and Tunnels Against Buckling During Emptying

    Schleiss, Anton; Manso, Pedro


    Using high-strength steels for pressure shafts and tunnel liners and taking into account significant rock mass participation allows the design of comparatively thin steel liners in hydropower projects. Nevertheless, during emptying of waterways, these steel linings may be endangered by buckling. Compared with traditional measures such as increased steel liner thickness and stiffeners, pressure relief valves are a very economical solution for protection of steel liners against critical extern...

  18. Analysis of operational methane emissions from pressure relief valves from biogas storages of biogas plants.

    Reinelt, Torsten; Liebetrau, Jan; Nelles, Michael


    The study presents the development of a method for the long term monitoring of methane emissions from pressure relief valves (PRV(1)) of biogas storages, which has been verified during test series at two PRVs of two agricultural biogas plants located in Germany. The determined methane emission factors are 0.12gCH4kWhel(-1) (0.06% CH4-loss, within 106days, 161 triggering events, winter season) from biogas plant A and 6.80/7.44gCH4kWhel(-1) (3.60/3.88% CH4-loss, within 66days, 452 triggering events, summer season) from biogas plant B. Besides the operational state of the biogas plant (e.g. malfunction of the combined heat and power unit), the mode of operation of the biogas flare, which can be manually or automatically operated as well as the atmospheric conditions (e.g. drop of the atmospheric pressure) can also affect the biogas emission from PRVs.

  19. A conceptual study on large-capacity safety relief valve (SRV) for future BWR plants

    Yamada, Katsumi; Tokunaga, Takashi; Iwanaga, Masakazu; Kurosaki, Toshikazu [Toshiba Corporation, Isogo Nuclear Engineering Center, Yokohama (Japan)


    This paper presents a conceptual study of Safety Relief Valve (SRV) which has larger flow capacity than that of the conventional one and a new structure. Maintenance work of SRVs is one of the main concerns for next-generation Boiling Water Reactor (BWR) plants whose thermal power is planned to be increased. Because the number of SRVs increases with the thermal power, their maintenance would become critical during periodic inspections. To decrease the maintenance work, reduction of the number by increasing the nominal flow rate per SRV and a new structure suitable for easier treatment have been investigated. From a parameter survey of the initial and maintenance cost, the optimum capacity has been estimated to be between 180 and 200 kg/s. Primarily because the number of SRVs decreases in inversely proportional to the capacity, the total maintenance work decreases. The new structure of SRV, with an internally mounted actuator, decreases the number of the connecting parts and will make the maintenance work easier. A 1/4-scale model of the new SRV has been manufactured and performance tests have been conducted. The test results satisfied the design target, which shows the feasibility of the new structure. (author)

  20. BWR suppression pool pressures during safety relief valve discharge. Final report

    Hwang, G.; Gay, R.R.


    An analytical understanding of the pool pressures measured during safety relief valve (SRV) discharge in BWRs equipped with x-quenchers has been developed and compared to experimental data. The local conditions inside the SRV discharge lines and inside of the x-quencher were modeled successfully with RELAP5. The measured pressure surges inside the quencher are successfully predicted by the code. In addition, the analytical predictions allow one to associate the peak pressure inside the quencher arm with the onset of air discharge into the suppression pool. A Rayleigh model of bubble dynamics successfully explained both the higher-frequency and the ensuing lower-frequency pressure oscillations that have been measured in suppression pools during SRV discharge tests. The higher-frequency oscillations are characteristic of an air bubble emanating from a single row of quencher holes. The lower-frequency pressure oscillations are characteristic of a large air bubble containing all the air expelled from one side of an x-quencher arm.

  1. Analytical model for computing transient pressures and forces in the safety/relief valve discharge line. Mark I Containment Program, task number 7. 1. 2

    Wheeler, A.J.


    An analytical model is described that computes the transient pressures, velocities and forces in the safety/relief valve discharge line immediately after safety/relief valve opening. Equations of motion are defined for the gas-flow and water-flow models. Results are not only verified by comparing them with an earlier version of the model, but also with Quad Cities and Monticello plant data. The model shows reasonable agreement with the earlier model and the plant data.

  2. Application of RELAP5/MOD1 for calculation of safety and relief valve discharge piping hydrodynamic loads. Final report. [PWR


    A series of operability tests of spring-loaded safety valves was performed at Combustion Engineering in Windsor, CT as part of the PWR Safety and Relief Valve Test Program conducted by EPRI on behalf of PWR Utilities in response to the recommendations of NUREG-0578 and the requirements of the NRC. Experimental data from five of the safety valve tests are compared with RELAP5/MOD1 calculations to evaluate the capability of the code to determine the fluid-induced transient loads on downstream piping. Comparisons between data and calculations are given for transients with discharge of steam, water, and water loop seal followed by steam. RELAP5/MOD1 provides useful engineering estimates of the fluid-induced piping loads for all cases.

  3. Research on the Digital Water Hydraulic Relief Valve Based on Fluent%基于Fluent的数字式水压溢流阀研究

    贾伟亮; 吴张永; 王娴; 王娟; 莫子勇


    The key technology of water hydraulic transmission was introduced. The structure of the digital water hydraulic relief valve was designed according to the characteristics of the digital valve. The model of flow field cavitation inside the digital water hydraulic relief valve was built and analyzed by Fluent software. The simulation results provide theory basis for the design of the relief valve.%介绍水液压传动的关键技术,根据数字阀的特点设计数字式水压溢流阀.建立其阀口气穴流场的数学模型,并用Fluent软件进行仿真分析,仿真结果为溢流阀的结构改进提供理论依据.

  4. Research on the water hammer protection of the long distance water supply project with the combined action of the air vessel and over-pressure relief valve

    Li, D. D.; Jiang, J.; Zhao, Z.; Yi, W. S.; Lan, G.


    We take a concrete pumping station as an example in this paper. Through the calculation of water hammer protection with a specific pumping station water supply project, and the analysis of the principle, mathematical models and boundary conditions of air vessel and over-pressure relief valve we show that the air vessel can protect the water conveyance system and reduce the transient pressure damage due to various causes. Over-pressure relief valve can effectively reduce the water hammer because the water column re-bridge suddenly stops the pump and prevents pipeline burst. The paper indicates that the combination set of air vessel and over-pressure relief valve can greatly reduce the quantity of the air valve and can eliminate the water hammer phenomenon in the pipeline system due to the vaporization and water column separation and re-bridge. The conclusion could provide a reference for the water hammer protection of long-distance water supply system.


    Harris, S.


    Risk-based inspection methods enable estimation of the probability of spring-operated relief valves failing on demand at the United States Department of Energy's Savannah River Site (SRS) in Aiken, South Carolina. The paper illustrates an approach based on application of the Frechet and Weibull distributions to SRS and Center for Chemical Process Safety (CCPS) Process Equipment Reliability Database (PERD) proof test results. The methodology enables the estimation of ANSI/ISA-84.00.01 Safety Integrity Levels (SILs) as well as the potential change in SIL level due to modification of the maintenance schedule. Current SRS practices are reviewed and recommendations are made for extending inspection intervals. The paper compares risk-based inspection with specific SILs as maintenance intervals are adjusted. Groups of valves are identified in which maintenance times can be extended as well as different groups in which an increased safety margin may be needed.

  6. The safety relief valve retrofit begins with a slow motion; Le lent demarrage des mises a niveau



    Through two decrees (September, 7 and October, 31), the fitting of a safety pressure relief valve was enforced by French Authorities on every LPG vehicle registered in France and circulating prior to January, 1, 2000. This decision is implemented for vehicles without this SPRV or fitted with a 'low flow' valve, i.e. with a flow under 17.7 m{sup 3}/mn. The fitting must be completed for December, 31, 2001 at the latest. The cost of the retrofit is covered up to 50% by LPG marketers and the Government. Today, the targeted LPG car owners, even these who were informed of this regulation, answer very slowly. Some 100,000 to 120,000 LPG vehicles must be re-equipped and, since the launching of Operation Reflexe GPL last September, only 1% of these vehicles were retro-fitted. Thus, new communication campaigns are prepared to speed up the scheme. (authors)

  7. Comparison Study on Thermal-Hydraulic Analysis Depending on Liquid Relief Valve Response for an Station Blackout in CANDU-6

    Kim, S. M.; Kho, D. W. [KHNP-CRI, Daejeon (Korea, Republic of); Choi, S. H.; Moon, B. J.; Kim, S. R. [Nuclear Engineering Service and Solution Co., Daejeon (Korea, Republic of)


    The purpose of this analysis is to compare the results of thermal-hydraulic analysis depending on liquid relief valve response during a station black out (SBO) events in CANDU-6. The primary heat transport system (PHTS) behavior following the postulated SBO is analyzed using CATHENA code. In the paper, analysis was performed to evaluate the effect on coolant system where LRVs are assumed to be opened or opened according to normal open characteristics in the condition of SBO. The result showed that the primary pressure boundary is extended from LRV to DCT and the effects on primary system behavior were neglectable.

  8. 基于CFD加油泵溢流阀的噪声分析%Analysis of the Noise of Oil Pump Relief Valves based on CFD

    马景勇; 谢松林; 童珍容; 苏华山


    为了减小在加油过程中ZCB90型加油泵溢流阀产生的噪声,按照溢流阀的实际结构和参数,建立了溢流阀内部流场的三维模型,应用计算流体动力学软件Fluent,对溢流阀的内部流场进行研究,给出了溢流阀内的压力场、流线分布图.对容易产生漩涡和负压的结构处进行了改进.结果表明,结构改进后的流场中漩涡区分布减小,最低压力得到提高,降低了气蚀和噪声发生的可能性.此研究工作为溢流阀的优化设计提供了理论依据,为降低在实际工作中溢流阀的噪声提供了思路.%In order to reduce the pressure relief valves noise of ZCB90 type pumps during refueling, relief valve three-di-mensional model of the internal flow field was established in accordance with the structure and parameters of the actual relief valves, the flow field of the relief valve with the application of computational fluid dynamics software Fluent was studied, the pressure field within the relief valve and the flow line maps was gotten. It improved the structure there prone to swirl and negative pressure. The results showed that the improved structure made the swirl distribution in the flow field was de-creased and the minimum pressure was improved, which reduced the likelihood of cavitation and noise. This research for the optimized design of the valves provides a theoretical basis and a guideline to reduce the noise of relief valve in the actual work. Though experiment of relief valve noise decreased significantly, it validated the theory mentioned in the paper.

  9. Mean-field theory of photoinduced formation of surface reliefs in side-chain azobenzene polymers

    Pedersen, Thomas Garm; Johansen, Per Michael; Holme, N.C.R.


    A mean-field model of photoinduced surface reliefs in dye containing side-chain polymers is presented. It is demonstrated that photoinduced ordering of dye molecules subject to anisotropic intermolecular interactions leads to mass transport even when the intensity of the incident light is spatially...... uniform. Theoretical profiles are obtained using a simple variational method and excellent agreement with experimental surface reliefs recorded under various polarization configurations is found. The polarization dependence of both period and shape of the profiles is correctly reproduced by the model....

  10. Analytical model for estimating drag forces on rigid submerged structures caused by LOCA and safety relief valve ramshead air discharges. [BWR


    Basic information is presented for estimating drag forces on rigid structural members submerged in a pressure suppression pool, caused by either the air discharge from a loss-of-coolant accident (LOCA), or the air bubble oscillation following safey relief valve ramshead discharge. Methods are described for estimating acceleration (unsteady) and standard (velocity-squared) drag force components for a variety of structural geometries.

  11. Analysis of a loss of feedwater transient with safety/relief valve stuck open in Chin Shan Nuclear Power Station

    Liao, L.Y.; Guey, C.N.; Chen, Y.B.; Lee, C.H.


    An analysis has been made with RELAP 4/MOD5 to simulate the system behavior of loss of feedwater transient with safety/relief valve stuck open in Chin Shan BWR. The initial conditions have been established with 105% rated power and 105% flow rate. System variables such as normalized power, steam dome pressure, core inlet flow rate, fuel cladding temperatures, separator mixture level, downcomer mixture level, and core inlet enthalpy have been calculated. A comparison has also been made between the results obtained and those documented in FSAR. It is observed that the general trends of system parameters in both cases are similar, differing slightly only in the timing of the sequence of events postulated to occur. The possibility of idling of ECCS as a result of pool swelling is ruled out. Core uncovery is not observed. In conclusion, the accident analyzed can be accommodated by the design incorporated in the Chin Shan Plant.

  12. 溢流阀先导阀芯的振动特性仿真研究%The Vibration Characteristics Simulation Research of the Relief Valve' s Pilot Valve

    王国志; 李光飞; 刘桓龙; 邓斌; 吕少恒


    The main vibration resource of the pilot operated computed relief valve is the vibration of pilot valve, the vibration of the pilot valve in the engineering is studed on. The vibration system dynamic model of the pilot valve is built, some parameters'effect on the vibration of the pilot valve is simulated and analyzed. The result shows, the steady flow force which make the valve closed , increase the length or decrease the diameter of the flow channel which combined the main valve with the pilot valve, lessen the air content in oil or decrease the oil working temperature which can reduce the vibration of pilot valve and have contribute to the stability of the relief valve.%先导式溢流阀振动的主要来源为先导阀的振动.针对先导阀在工程中出现的振动问题进行研究.建立先导阀芯振动的系统动力学模型,分析相关参数对先导阀振动特性的影响.结果表明,增大连接主阀上腔和先导阀前端孔道的长度、减小孔道直径、减少油液的含气量和减少油液工作温度等有助于减少先导阀的振动,提高溢流阀工作稳定性.

  13. RELAP5/MOD3 assessment for calculation of safety and relief valve discharge piping hydrodynamic loads. International agreement report

    Stubbe, E.J.; VanHoenacker, L.; Otero, R. [TRACTEBEL, Brussels (Belgium)


    This report presents an assessment study for the use of the code RELAP 5/MOD3/5M5 in the calculation of transient hydrodynamic loads on safety and relief discharge pipes. Its predecessor, RELAP 5/MOD1, was found adequate for this kind of calculations by EPRI. The hydrodynamic loads are very important for the discharge piping design because of the fast opening of the valves and the presence of liquid in the upstream loop seals. The code results are compared to experimental load measurements performed at the Combustion Engineering Laboratory in Windsor (US). Those measurements were part of the PWR Valve Test Program undertaken by EPRI after the TMI-2 accident. This particular kind of transients challenges the applicability of the following code models: two-phase choked discharge; interphase drag in conditions with large density gradients; heat transfer to metallic structures in fast changing conditions; two-phase flow at abrupt expansions. The code applicability to this kind of transients is investigated. Some sensitivity analyses to different code and model options are performed. Finally, the suitability of the code and some modeling guidelines are discussed.

  14. Navier-Stokes flow field analysis of compressible flow in a high pressure safety relief valve

    Vu, Bruce; Wang, Ten-See; Shih, Ming-Hsin; Soni, Bharat


    The objective of this study is to investigate the complex three-dimensional flowfield of an oxygen safety pressure relieve valve during an incident, with a computational fluid dynamic (CFD) analysis. Specifically, the analysis will provide a flow pattern that would lead to the expansion of the eventual erosion pattern of the hardware, so as to combine it with other findings to piece together a most likely scenario for the investigation. The CFD model is a pressure based solver. An adaptive upwind difference scheme is employed for the spatial discretization, and a predictor, multiple corrector method is used for the velocity-pressure coupling. The computational result indicated vortices formation near the opening of the valve which matched the erosion pattern of the damaged hardware.

  15. Standard Practice for Installation, Inspection, and Maintenance of Valve-body Pressure-relief Methods for Geothermal and Other High-Temperature Liquid Applications

    American Society for Testing and Materials. Philadelphia


    1.1 This practice covers installation, inspection, and maintenance of valve body cavity pressure relief methods for valves used in geothermal and other high-temperature liquid service. The valve type covered by this practice is a design with an isolated body cavity such that when the valve is in either the open or closed position pressure is trapped in the isolated cavity, and there is no provision to relieve the excess pressure internally. 1.2 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

  16. Analysis of valve port leakage on direct operated relief valve under foundation vibration%基础振动下直动式溢流阀的阀口泄漏分析

    王蔚坪; 张怀亮; 章国亮


    Aiming at the problem that vibration caused by tunnel boring machine (TBM ) during the process of tunneling has effect on leakage in hydraulic components , the relief valve leakage rate caused by foundation vibration and structure parameters was analyzed . Taking the direct operated relief valve installed on TBM as the example , a mathematical model of valve port leakage of relief valve under foundation vibration was established .Critical inlet pressure was determined by calculating the leakage caused by foundation vibrations . Results showed that the amount of valve port leakage increased approximately linearly as the amplitude and frequency of vibration increased . When the spring stiffness was smaller than 1 .3 × 105 N/m ,the valve leakage increased as the spring stiffness increased ;while when the spring stifness equaled to 1 .3 × 105 N/m ,the valve leakage reached the maximum .Reducing spring stiffness and spool mass can decrease the valve port leakage fault caused by foundation vibration significantly ,and improve the working stability of relief valve .%针对硬岩掘进机(TBM )在掘进过程中产生的振动影响液压元件内泄漏的问题,分析基础振动及结构参数对溢流阀阀口泄漏量的影响规律.以安装在TBM基础上的直动式溢流阀为研究对象,建立基础振动下溢流阀的阀口泄漏量数学模型.通过计算基础振动引起的溢流阀阀口泄漏量,确定溢流阀发生阀口泄漏时的临界入口压力.结果表明:阀口泄漏量随着基础振动振幅及频率的增大而近似线性增大;当弹簧刚度小于1.3×105 N/m时,阀口泄漏量随着弹簧刚度的增大而增大;当弹簧刚度为1.3×105 N/m时,阀口泄漏量达到最大值;减小弹簧刚度和阀芯质量可以显著减少因基础振动引起的阀口泄漏故障,从而提高溢流阀的工作稳定性.

  17. Aging and service wear of spring-loaded pressure relief valves used in safety-related systems at nuclear power plants

    Staunton, R.H.; Cox, D.F. [Oak Ridge National Lab., TN (United States)


    Spring-loaded pressure relief valves (PRVS) are used in some safety-related applications at nuclear power plants. In general, they are used in systems where, during accidents, pressures may rise to levels where pressure safety relief is required for protection of personnel, system piping, and components. This report documents a study of PRV aging and considers the severity and causes of service wear and how it is discovered and corrected in various systems, valve sizes, etc. Provided in this report are results of the examination of the recorded failures and identification of trends and relationships/correlations in the failures when all failure-related parameters are considered. Components that comprise a typical PRV, how those components fail, when they fail, and the current testing frequencies and methods are also presented in detail.

  18. The performance evaluation for passive type's pressurizer and pilot operated safety relief valve of SMART

    Lee, Jun; Yoon, Ju Hyeon


    In this report, the performance for PZR of SMART has been evaluated in which the passive cold PZR and PRHRS had been installed and the FW control system that reactor power is controlled by FW flow rate had been adopted. After the present analysis of the coolant volume of PZR end cavity, it was evaluated that the results could be satisfied if the coolant volume and pressure are controlled in order to be maintained within their set points. Also after the analysis of the gas volume, it was evaluated that the results is much satisfied. Especially, it was analyzed that the peak pressure of end cavity is raised only about 50%(0.6 MPa) as contrasted with the commercial plants. Also, the relieving capacity for pilot operated safety relief valve(POSRV) of SMART was analyzed. The related requirements of 10 CFR 50.55a (c) (1), ASME Code, Sec. III, NB-7000, NUREG-0800 were applied to the analysis. After the present analysis, it was evaluated that the RCS peaking pressure is about 18.2 MPa, 107% of system design pressure, and that it has 3% margin against the design requirement. Also, after the additional analysis, it was evaluated that the open dead/stroke time of POSRV has just a little effect on the peak pressure of PZR EC and MCP discharge.

  19. The performance evaluation for passive type's pressurizer and pilot operated safety relief valve of SMART

    Lee, Jun; Yoon, Ju Hyeon


    In this report, the performance for PZR of SMART has been evaluated in which the passive cold PZR and PRHRS had been installed and the FW control system that reactor power is controlled by FW flow rate had been adopted. After the present analysis of the coolant volume of PZR end cavity, it was evaluated that the results could be satisfied if the coolant volume and pressure are controlled in order to be maintained within their set points. Also after the analysis of the gas volume, it was evaluated that the results is much satisfied. Especially, it was analyzed that the peak pressure of end cavity is raised only about 50%(0.6 MPa) as contrasted with the commercial plants. Also, the relieving capacity for pilot operated safety relief valve(POSRV) of SMART was analyzed. The related requirements of 10 CFR 50.55a (c) (1), ASME Code, Sec. III, NB-7000, NUREG-0800 were applied to the analysis. After the present analysis, it was evaluated that the RCS peaking pressure is about 18.2 MPa, 107% of system design pressure, and that it has 3% margin against the design requirement. Also, after the additional analysis, it was evaluated that the open dead/stroke time of POSRV has just a little effect on the peak pressure of PZR EC and MCP discharge.

  20. Can postoperative mean transprosthetic pressure gradient predict survival after aortic valve replacement?

    Koene, Bart M.; Hamad, Mohamed A. Soliman; Bouma, Wobbe; Mariani, Massimo A.; Peels, Kathinka C.; van Dantzig, Jan-Melle; van Straten, Albert H.

    In this study, we sought to determine the effect of the mean transprosthetic pressure gradient (TPG), measured at 6 weeks after aortic valve replacement (AVR) or AVR with coronary artery bypass grafting (CABG) on late all-cause mortality. Between January 1998 and March 2012, 2,276 patients (mean age

  1. Technical evaluation report, TMI action NUREG-0737 (II.D.1), relief and safety valve testing, Comanche Peak, Unit 2, Docket No. 50-446

    Fineman, C.P.


    In the past, safety and relief valves installed in the primary coolant system of light water reactors have performed improperly. As a result, the authors of NUREG-0578 (TMI-2 Lessons Learned Task Force Status Report and Short-Term Recommendations) and, subsequently, NUREG-0737 (Clarification of TMI Action Plan Requirements) recommended development and completion of programs to do two things. First, the programs should reevaluate the functional performance capabilities of pressurized water reactor safety, relief, and block valves. Second, they should verify the integrity of the pressurizer safety and relief valve piping systems for normal, transient, and accident conditions. This report documents the review of those programs by EG&G Idaho, Inc. Specifically, this report documents the review of the Comanche Peak, Unit 2, Applicant response to the requirements of NUREG-0578 and NUREG-0737. This review found the Applicant provided an acceptable response reconfirming they met General Design Criteria 14, 15, and 30 of Appendix A to 10 CFR 50 for the subject equipment.

  2. 水击泄压阀在成品油管道的应用%Application of Water Hammer Pressure Relief Valve in the Product Pipeline

    刘洋; 刘威


    The water hammer pressure relief valve is one of the protective equipments of product pipeline. It prevents the piping system through venting the excess pressure. According to 10 years of practical experience of applying the water hammer pressure relief valve in the Lanzhou-Chengdu-Chongqing pipeline, this paper introduces the water hammer pressure relief valve from the structure and principle, routine operations, maintenance and failure analysis and its improvements in the application process.%水击泄压阀是成品油管道的保护设备之一,通过泄放多余的压力防止管道系统受到破坏.本文根据水击泄压阀在兰成渝输油管道应用10年来的实际经验,从水击泄压阀的结构及原理、常规操作、维护保养及故障分析等方面介绍了水击泄压阀以及其在应用过程中的改进.

  3. Taps/valves in extreme conditions. Choice for tap-actuator sets for refining and petrochemical operations in severe conditions. Main steam isolation valves in extremely severe conditions. Presentation of the SRV (Safety Relief Valve) development; Robinets vannes en conditions extremes. Choix d`ensembles robinets-operateurs pour des operations en conditions severes dans le raffinage et la petrochimie. Vannes d`isolement vapeur principales en conditions tres severes. Presentation du developpement de la vanne SRV (safety relief valve)

    Brunet, X.F.; Aubry, F. [Institut Francais du Petrole, 92 - Rueil-Malmaison (France); Guesnon, D. [Technicatome Cadarache, 13 - Saint-Paul-Lez-Durance (France); Martin, R. [Vanatome, 07 - Annonay (France); Mainguette, Ph. [Adareg (France)


    This series of 3 papers was presented during a workshop organized by the French Society of mechanical engineers in 1997. The aim of the workshop was to take stock of the most recent developments in the domain of taps and valves devoted to extreme condition uses (very high or very low temperatures or pressures and corrosive ambiences). The first paper deals with selection criteria for the choice of valve-actuator sets devoted to high temperature liquid aromatic fluids in the refining and petrochemical industries (technical specifications, selection, qualification tests, quality control and tests feedback). The second paper presents the global conceiving process which led to adapt a general concept of valve to a specific application to propulsion reactors of nuclear ships: the steam isolation valves (technical specifications, particular constraints, prototype and serial product, maintenance and experience feedback). The third paper concerns the development of a safety relief valve for the superfluid helium cooling system of the superconducting magnets of the future LHC (Large Hadron Collider) of the CERN (technical specifications, general characteristics, functioning principle, technology and conceiving, test of prototypes and results). (J.S.)

  4. Calculation of Relief Capacity of Process Safety Valve under Control Valve Failure%控制阀故障工况下安全阀泄放量的计算

    曹虎; 周琛; 黄世勇; 王富丽


    It was one of the key factors for the selection of process safety valve (PSV), that was to accurately determine PSV discharge. In the standards,《HG/T20570.2-1995 Setting and Selection of PSV》, the formula to calculate the liquid relief capacity of PSV under control valve failure was not introduced. Basing on some engineering experiences, this paper provided a kind of calculation method to quantify the liquid relief capacity of PSV under control valve failure. Moreover, a example was illustrated to explain how to use this calculation method.%准确确定安全阀的泄放量是安全阀选型的关键之一。标准《HG/T 20570.2-1995安全阀的设置和选用》中针对控制阀故障工况下液体泄放量的计算未提供有效的计算公式。本文通过工程经验总结,提供一种控制阀故障工况下安全阀液体泄放量的计算方式,并举例说明了其使用方法。

  5. Implementation of an enlarged model of the safety valves and relief in the plant integral model for the code RELAP/SCDAPSIM; Implementacion de un modelo ampliado de las valvulas de seguridad y alivio en el modelo integral de planta para el codigo RELAP/SCDAPSIM

    Amador G, R.; Ortiz V, J.; Castillo D, R. [ININ, Carretera Mexico-Toluca s/n, 52750 Ocoyoacac, Estado de Mexico (Mexico); Hernandez L, E. J. [Instituto Tecnologico de Toluca, Av. Tecnologico s/n, Fracc. La Virgen, 52149 Metepec, Estado de Mexico (Mexico); Galeana R, J. C. [Universidad del Valle de Mexico, Campus Toluca, Av. de Las Palmas 136, 52140 Metepec, Estado de Mexico (Mexico); Gutierrez, V. H., E-mail: [Universidad Autonoma Metropolitana, Unidad Azcapotzalco, Av. San Pablo 180, Col. Reynosa Tamaulipas, 02200 Mexico D. F. (Mexico)


    The present work refers to the implementation of a new model on the logic of the safety valves and relief in the integral model of the Nuclear Power Plant of Laguna Verde of the thermal-hydraulic compute code RELAP/SCDAPSIM Mod. 3.4. The new model was developed with the compute package SIMULINK-MATLAB and contemplates all the operation options of the safety valves and relief, besides including the availability options of the valves in all the operation ways and of blockage in the ways of relief and low-low. The implementation means the elimination of the old model of the safety valves and to analyze the group of logical variables, of discharge and available control systems to associate them to the model of package SIMULINK-MATLAB. The implementation has been practically transparent and 27 cases corresponding to a turbine discharge were analyzed with the code RELAP/SCDAPSIM Mod. 3.4. The results were satisfactory. (Author)

  6. 先导腔动压反馈比例溢流阀的动态特性分析%Dynamic Characteristic Analysis of Proportional Relief Valve with Pilot Chamber Dynamic Pressure Feedback

    孙文毅; 陈淑梅; 颜滨曲; 黄彬


    比例溢流阀是保证工程机械运动稳定性的重要元件,针对普通比例先导溢流阀工作过程中响应速度慢和压力超调大的缺陷,该文设计了一款先导腔动压反馈式比例溢流阀.通过数学建模分析了溢流阀的静态和动态特性,并运用AMESim软件对所设计的比例溢流阀进行仿真分析,研究了影响溢流阀性能的结构参数,并验证了数学模型的正确性;用液压刚度替代了弹簧刚度,在结构上克服了弹簧工作过程中响应速度迟缓的缺点,有效改善了溢流阀的寿命.仿真结果表明,改进后的溢流阀较普通比例先导溢流阀的调压精度好、调压范围大,其性能上有明显的提高,对溢流阀的研究设计有一定的参考价值.%Proportional relief valves are the important components to ensure the stability of mechanical engineering movement . This paper designs a novel pilot cavity dynamic pressure feedback proportional relief valve for ordinary proportional pilot-operated relief lacking of slow response and large pressure overshoot in the working process. Theoretically the paper builds mathematical model for analyzing the static and dynamic characteristics of this relief valve, and simulates the model of the designed proportional relief valve by AMESim, which analyzes the structural parameters affecting the relief valve performance and verifies the correctness of the mathematical model. The valve uses hydraulic rigidity to replace spring stiffness, structurally overcoming the disadvantage of low response in the working process, and ef-fectively improving the life of the relief. Simulation results show that the improved relief has good precision regulator, large pressure regula-tion, and its performance has been significantly improved comparing with ordinary proportional pilot-operated relief, which has some refer-ence value for the study and design of the relief valve.

  7. Coincident steam generator tube rupture and stuck-open safety relief valve carryover tests: MB-2 steam generator transient response test program

    Garbett, K; Mendler, O J; Gardner, G C; Garnsey, R; Young, M Y


    In PWR steam generator tube rupture (SGTR) faults, a direct pathway for the release of radioactive fission products can exist if there is a coincident stuck-open safety relief valve (SORV) or if the safety relief valve is cycled. In addition to the release of fission products from the bulk steam generator water by moisture carryover, there exists the possibility that some primary coolant may be released without having first mixed with the bulk water - a process called primary coolant bypassing. The MB-2 Phase II test program was designed specifically to identify the processes for droplet carryover during SGTR faults and to provide data of sufficient accuracy for use in developing physical models and computer codes to describe activity release. The test program consisted of sixteen separate tests designed to cover a range of steady-state and transient fault conditions. These included a full SGTR/SORV transient simulation, two SGTR overfill tests, ten steady-state SGTR tests at water levels ranging from very low levels in the bundle up to those when the dryer was flooded, and three moisture carryover tests without SGTR. In these tests the influence of break location and the effect of bypassing the dryer were also studied. In a final test the behavior with respect to aerosol particles in a dry steam generator, appropriate to a severe accident fault, was investigated.

  8. Analytically predicted versus measured response of a free-standing steel containment vessel subjected to safety-relief valve discharge loads

    Good, H.; Lewis, M.; Fitch, J.; Mattson, R.


    Following the actuation of safety-relief valves in BWR nuclear power plants, first water then air and steam are cleared from the discharge lines through quencher devices into a suppression pool. This clearing results in water spike, air bubble, and condensation pressure loads applied to structures in the pool, and the surrounding containment vessel. The Leibstadt Nuclear Power Plant has the only fre-standing steel Mark III containment vessel in the world. All other steel Mark III containment vessels have concrete backing in the suppression pool region, which dampens clearing load responses. As such, it is of interest to note how this steel vessel responds to discharge pressures, and compare these responses to analytically predicted results. The purpose of this paper is to compare the analytical results used to design the steel containment vessel with the responses measured during in-plant testing. The analytical methods considered the effects of fluid-structure interaction. The test program included initial and consecutive actuations of a single valve, and initial actuation of multiple (four) valves. The conclusion of the comparison is that, in general there are large conservatisms in the analytical predictions versus measured responses.

  9. Structural Design and Performance Simulation of Digital Water Hydraulic Relief Valve%数字式纯水溢流阀的结构设计与性能仿真分析

    颜凌云; 武鹏飞; 包宗贤; 李红星


    This article describes the digital water hydraulic relief valve by self-designed, And through the Matlab/Simulink software simulation the static and dynamic performance of the relief valve, Then the simulation results verify the correctness of the design theory.%该文介绍了自行设计的数字式纯水液压溢流阀,并通过Matlab/Simulink软件对溢流阀的静动态性能进行了仿真分析,由仿真结果验证了设计理论的正确性.

  10. Design and Simulation for Tandem Type Ultra High Pressure Relief Valve%串联式超高压溢流阀设计与仿真研究

    周晓君; 余敏超


    A tandem type ultra high pressure relief value was presented. The relief value could be used in hydraulic system with high pressure and small stream. It is characterized as simple structure, low noise, long life. Its mathematic model was built based on classical control theory. Then it was simulated by MATLAB/Simulink. The results are helpful for the optimization design of tandem type ultra high pressure relief valve.%提出一种串联式超高压溢流阀,适合应用在压力高、流量小的液压系统中,具有结构简单、噪声低、寿命长等优点.根据经典控制理论建立超高压溢流阀的动态特性方程,并应用MATLAB/Simulink软件对其进行动态特性仿真.仿真结果对串联式超高压溢流阀的优化设计有一定的指导意义.

  11. Design guidelines for PWR pressurizer safety and relief valve discharge piping to minimize potential operating and piping qualification problems

    Adams, T.M.; Chang, K.C.; Campbell, T.E.


    General system design considerations such as functional requirements, valve types and operation, and various loading conditions are discussed. General guidelines for the piping layout, support design, and embedment selection are presented and discussed. Also presented and discussed are potential system operating problems which can arise from an improper design. 3 refs.

  12. Evaluation of the simultaneous action of earthquake, LOCA and SRV on Mark-III containment and drywell structures. [Safety Relief Valve

    Philippacopoulos, A.J.; Reich, M.


    The containment and drywell structures of a generic Mark-III nuclear power facility are investigated with respect to their structural response when subjected to various load combinations that may occur during their operational lifetime. Both structures are idealized with three-dimensional finite element models. In addition a lumped-mass cantilever beam representation of the containment and drywell structures is developed and used for the soil-structure interaction analysis. The types of dynamic events considered include earthquakes, loss-of-coolant-accidents (LOCA) and those generated by safety/relief valve actuations. The evaluation of the combined actions of these dynamic events is first performed by using combination methods such as Absolute Sum (ABS) and Square-Root-of-the-Sum-of-the-Squares (SRSS). A Monte Carlo simulation procedure is subsequently used for probabilistic evaluation of the combinations.

  13. 氮气式水击泄压阀初启阶段动态特性研究%Study on dynamic characteristics of nitrogen surge relief valve in opening process

    李树勋; 王虎斌; 范宜霖; 徐晓刚


    For the requirements that nitrogen‐type pressure relief valve for petrol gathering pipeline should open quickly ,close slowly and release largely at a small opening degree ,principle and dynamic characteristic of nitrogen‐type pressure relief valve were analyzed in theory and simulated .After the a‐nalysis of opening and closing process on nitrogen‐type pressure relief valve ,the valve core dynamics equations and spring stiffness expression were established ,and ANSYS CFX software was used to dy‐namically simulate nitrogen‐type surge relief valve′s initial opening process on this basis .The medium velocity and turbulent energy change process in the initial opening process of the relief valve core seal‐ing surface were analyzed ,and the influences of different pressure and the valve core chamber nitrogen pressure of relief valve on dynamic characteristic were discussed .%针对石油集输管网中氮气式水击泄压阀快开慢关、小开度下大泄放量的要求,对氮气式水击泄压阀的工作原理及初启阶段动态特性进行理论分析及仿真研究。通过对氮气式水击泄压阀开启过程的分析,建立阀芯动力学方程及阀芯腔室近似氮气弹簧刚度表达式,在此基础上运用ANSYS CFX软件进行了泄压阀初启阶段动态仿真模拟,研究了在泄压阀初启阶段阀芯密封面处介质流速及湍动能的变化过程,并分析了不同超压比和阀芯腔室氮气压力对泄压阀初启阶段动态特性的影响。

  14. KR500X泄压阀在长输管道中的应用%Application of KR500X Pressure Relief Valve in Long-distance Water Conveyance Pipeline

    姜海萍; 郑全兴


    泄压阀是水力控制阀的一种,能有效防止水击.详细介绍了泄压阀的结构、工作原理、特点、安装和日常维护注意事项.泄压阀通径的选用还没有成熟的理论依据,扬州第五水厂选用泄压阀的方法是一次探索.水厂投产两年来,输水管道运行平稳,确保了城市供水安全.%The pressure relief valve is one of the hydraulic control valves, which can effectively prevent water hammer. The structure of the pressure relief valve, its working principle, characteristics, installation and daily maintenance are introduced. Up to now, no mature theory has been found about the selection of the diameter of the pressure relief valves. Hence the approach adopted by Yangzhou Fifth Water Plant is a successful practice. The water conveyance pipeline has been running smoothly since the water plant was put into operation two years ago, which greatly ensures the safety of the city water supply.

  15. Research of the relief images forming process on the imprints by means of screen UV-varnishes

    Sergіy Piknevych


    Full Text Available This article describes the process of relief image forming by UV-varnishes on self-adhesive labels done by means of screen printing plates with different screen mesh - 36 and 90 lines per cm. The influence of substrates’ surface energy on the process of UV-varnish transfer has been investigated. It was defined a disproportional distribution of surface energy on nonprinted self-adhesive paper and it was determined the influence of screen ruling on the varnishing relief’s height as well as the value of substrate’s surface energy and viscosity of UV- varnish.

  16. Technical evaluation report TMI action -- NUREG-0737 (II.D.1). Relief and safety valve testing, Watts Bar Nuclear Plant, Units 1 and 2 (Dockets 50-390 and 50-391)

    Fineman, C.P.


    In the past, safety and relief valves installed in the primary coolant system of light water reactors have performed improperly. As a result, the authors of NUREG-0578 (TMI-2 Lessons Learned Task Force Status Report and Short-Term Recommendations) and, subsequently, NUREG-0737 (Clarification of TMI Action Plan Requirements) recommended development and completion of programs to do two things. First, they should reevaluate the functional performance capabilities of pressurized water reactor safety, relief, and block valves. Second, they should verify the integrity of the pressurizer safety and relief valve piping systems for normal, transient, and accident conditions. This report documents the review of those programs by Lockheed Idaho Technologies Company. Specifically, this report documents the review of the Watts Bar Nuclear Plant, Units 1 and 2, Applicant response to the requirements of NUREG-0578 and NUREG-0737. This review found the Applicant provided an acceptable response reconfirming they met General Design Criteria 14, 15, and 30 of Appendix A to 10 CFR 50 for the subject equipment. It should also be noted Lockheed Idaho performed this review for both Units 1 and 2. However, the applicability of this review to Unit 2 depends on verifying that the Unit 2 as-built system conforms to the Unit 1 design reviewed in this report.

  17. Flow Rate Analysis of 3/2 Directional Pneumatic Valve by Means Of Ansys Cfx Software

    Slawomir BLASIAK


    Full Text Available The main purpose of this paper was to develop a selection method of the pneumatic connectors for directional 3/2 valve. The method was established to minimize resistance and loss of pressure in the valve with mounted pneumatic connections for the selected pipe diameters. Directional valve was modeled in 3D CAD software SolidWorks while 3D models of the air connections have been downloaded from the website of one of the leading suppliers of pneumatic. Based on developed solid model the simulation of compressed air flow in the software for computational fluid dynamics Ansys CFX was conducted. The studies using CFD methods helped to determine which air connections best meet the assumptions. Performed numerical tests enable proper selection of items to the newly designed pneumatic systems for a particular group of valves. As a consequence, this translates into a reduction in energy consumption and improve the efficiency of the entire pneumatic complex system.

  18. Simulation and Optimal Design of High-Pressure-Differential and High-Solid-Phase Relief Valves%高压差高固含量减压阀的仿真优化设计

    王新昶; 孙方宏; 孙乐申; 丁庆华; 彭东辉


    Relief valves used in the coal liquefaction equipment are running in an extremely harsh environment with extraordinarily high pressure differential and intensely slurry flow erosion.Based on the finite volume method(FVM),the pressure and flow distributions of relief valves were analyzed,with K-ε turbulence and Mixture multiphase model.Moreover,for the new-style relief valves,variations of pressure drops with valve apertures and turbulence intensities with depths of valve seat hole were studied.Considering the fluid-erosion theory,optimal design was accomplished and the easy-wearing positions of the relief valves were accurately predicted to provide theoretical basis for the choice of wear resistant materials.The application results show that the easy-wearing positions are coincide with the predictions.Moreover,the working lifetime is largely elongated up to 1 200 hours and suitable for the practical application.%基于有限容积法,采用K-ε双方程湍流模型和Mixture多相流模型,对高压差高固态浓度流体冲蚀极端工况条件下工作的煤液化减压阀阀体内的压力分布和流场状态进行了计算流体动力学分析,研究了新型结构减压阀在不同开度下压降的变化情况,以及不同阀座孔深度下湍流强度的变化情况.结合流体冲蚀理论,完成了对其结构的优化改进,并对易磨损部位做出了精确预测,为关键部位耐磨材料的筛选提供了理论依据.实际应用实验结果表明,该新型减压阀使用过程中易磨损部位与仿真预测一致,使用寿命超过了1 200 h,满足实际应用需求.

  19. Modelling mean transit time of stream base flow during tropical cyclone rainstorm in a steep relief forested catchment

    Lee, Jun-Yi; Huang, -Chuan, Jr.


    Mean transit time (MTT) is one of the of fundamental catchment descriptors to advance understanding on hydrological, ecological, and biogeochemical processes and improve water resources management. However, there were few documented the base flow partitioning (BFP) and mean transit time within a mountainous catchment in typhoon alley. We used a unique data set of 18O isotope and conductivity composition of rainfall (136 mm to 778 mm) and streamflow water samples collected for 14 tropical cyclone events (during 2011 to 2015) in a steep relief forested catchment (Pinglin, in northern Taiwan). A lumped hydrological model, HBV, considering dispersion model transit time distribution was used to estimate total flow, base flow, and MTT of stream base flow. Linear regression between MTT and hydrometric (precipitation intensity and antecedent precipitation index) variables were used to explore controls on MTT variation. Results revealed that both the simulation performance of total flow and base flow were satisfactory, and the Nash-Sutcliffe model efficiency coefficient of total flow and base flow was 0.848 and 0.732, respectively. The event magnitude increased with the decrease of estimated MTTs. Meanwhile, the estimated MTTs varied 4-21 days with the increase of BFP between 63-92%. The negative correlation between event magnitude and MTT and BFP showed the forcing controls the MTT and BFP. Besides, a negative relationship between MTT and the antecedent precipitation index was also found. In other words, wetter antecedent moisture content more rapidly active the fast flow paths. This approach is well suited for constraining process-based modeling in a range of high precipitation intensity and steep relief forested environments.

  20. Mark I Containment Program. Scaling analysis for modeling initial air clearing caused by reactor safety/relief valve discharge. [BWR

    Schrum, R.W.


    A generalized method of similitude is introduced and applied to develop scaling relationships for a General Electric Mark I suppression pool. A scale model is proposed to model suppression pool wall loads due to air flow through a T-quencher discharge device. The scaling relationships developed provide the means for relating scale model parameters (i.e., pressure, velocity,) to full scale.


    Hu Yanping; Huang Zhichu; Liu Deshun; Mao Zhengyu


    A new construction of the relief valve is presented with pilot G-( bridg hydraulic resistances network. The design theory of G-( bridge relief valve is studied and the formulas for designing the relief valve with zero static pressure override are obtained. The static performances of the relief valve are experimentally investigated. The theoretical and experimental results show that the static pressure override of the developed relief valve can be zero, i.e. when the overflow increases the control pressure is kept constant.

  2. Some questions about the set pressure and relief area of safety valves in GB 150-1998%GB 150—1998中安全阀开启压力和排放面积疑义

    李志义; 王淑兰; 丁信伟


    The irrationality is analyzed of the design press ure of pressurevessels protected with safety valves, which is regulated in GB 1 50-1998 Steel Pressure Vessels. The error is pointed out relating to the calcul ation of the relief area of safety valves under subcritical flowing in GB 150-19 98. The importance correctly dealing with these two questions is stressed.%分析了GB150—1998《钢制压力容器》对装有安全阀的压力容器设计压力确定方法的不合理性,指出了其附录B中规定的亚临界条件下,安全阀排放面积计算式的错误,强调了正确处理这两个问题的重要性。

  3. 一种高压大流量气动定差压力控制阀的研究%Development of A Novel Pneumatic Relief Valve with High Pressure and Large Flow Capacity

    杨曙东; 李壮云


    In this paper, a novel pneumatic relief valve with high pressure and large flow capacity is presented, its structure characteristics are also presented. And then the valve's performances are investigated by theory analysis and experiments. Because the valve uses a single stage poppet and a rubber membrane with corrugations and air cushion bearing, it shows rapid response, higher pressure control precision and good adaptability to a large range of working pressure. This valve has been used in a projecting system.%介绍一种高压、大流量气动定差压力控制阀及其结构特点,对其性能进行了理论分析和实验研究。由于采用了直动膜片式放大结构和气体静压支承原理,该阀具有响应灵敏、控制精度高、自适应能力强等优点。目前,该阀已用于某发射装置。

  4. 46 CFR 153.368 - Pressure-vacuum valves.


    ... 46 Shipping 5 2010-10-01 2010-10-01 false Pressure-vacuum valves. 153.368 Section 153.368 Shipping... Systems § 153.368 Pressure-vacuum valves. (a) The pressure side of a required pressure-vacuum relief valve... relief valve must meet the requirements of Subpart 162.017 of this chapter....

  5. Increasing the safety valve relief section of safety valves for discharge of a viscous liquid phase; Zur Vergroesserung des Entlastungsquerschnitts von Sicherheitsventilen bei der Bemessung im Fall des Austrags einer viskosen Fluessigphase

    Wieczorek, M.; Friedel, L. [Technische Univ. Hamburg-Harburg, Hamburg (Germany). Arbeitsbereich Stroemungsmechanik


    The cross section of safety valves is widened on the basis of a viscosity-dependend correction factor for higher-viscosity liquids. This method is presumably based on the results of investigations in control valves, and the viscosity correction factors used are therefore compared with those of safety valves. The corrections for safety valves according to API RP 520 for safety valves and draft DIN EN 60534-2-1 for control valves are in the same order of magnitude, while the correction according to Baumann is quite different. In principle, it can be seen that measurements will be required for validating the corrections for safety valves. [German] Der Stroemungsquerschnitt von Sicherheitsventilen in dem Fall einer Durchstroemung mit hoeher viskosen Fluessigkeiten wird mit Hilfe eines viskositaetsabhaengigen Korrekturfaktors vergroessert. Diese Vorgehensweise beruht vermutlich auf den Ergebnissen von Untersuchungen in Regelventilen, daher wurden die in diesem Bereich verwendeten Viskositaet-Korrekturen mit denen fuer Sicherheitsventile verglichen. Die Groessenordnung der Korrekturen gemaess API RP 520 fuer Sicherheitsventile und DIN (Entwurf) EN 60534-2-1 fuer Regelventile unterscheiden sich wenig voneinander. Die notwendige Vergroesserung entsprechend Baumann unterscheidet sich dagegen teilweise deutlich. Im Prinzip ist erkennbar, dass Messungen zur Validierung der Korrekturen fuer Sicherheitsventile erforderlich sind. (orig.)

  6. Excessive blowdown: leads to relief valve slowdowns: Difference in force balance between closed and open valve states determines the extent of the blowdown, which necessitates careful adjustment of seat and poppet dimensions

    Archer, Robert


    ... of the valve. [FIGURE 1 OMITTED] For the valve shown in Figure 1, fluid flow occurs across the seat area [A.sub.1] (an orifice) and is driven by the pressure difference between [p.sub.1] and [p.sub.0]. Normally, this backpressure eventually leads to a sump at atmospheric pressure, such as a reservoir. Sometimes, however, the diameter of downstream t...

  7. Valve's Way

    Phanish Puranam


    Full Text Available What can we learn from outliers? While statisticians rightly warn us against their non-representativeness, we believe it is also true that thinking carefully about what makes them atypical may improve our understanding of the typical case. This is the premise behind the Organization Zoo series. Valve Corporation (Valve is an unusual firm. It is a rare example of a firm that appears to operate without any formal hierarchy in its organization. What can we learn about the viability of authority hierarchies from Valve’s way of organizing? We wrote a brief account of Valve based on public information sources and asked several renowned organizational experts to comment on this unusual firm. We asked them to write a short commentary on what the Valve example means for organizational theorists and practitioners. Thankfully, they all accepted, and we are excited to present the results of their thinking in this first “exhibit” in the Organization Zoo.

  8. 46 CFR 64.67 - Shutoff valve.


    ... 46 Shipping 2 2010-10-01 2010-10-01 false Shutoff valve. 64.67 Section 64.67 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) MARINE ENGINEERING MARINE PORTABLE TANKS AND CARGO HANDLING SYSTEMS Pressure Relief Devices and Vacuum Relief Devices for MPTs § 64.67 Shutoff valve. A shutoff...

  9. Experimental investigations on the fluid-mechanics of an electrospun heart valve by means of particle image velocimetry.

    Del Gaudio, Costantino; Gasbarroni, Pier Luca; Romano, Giovanni Paolo


    End-stage failing heart valves are currently replaced by mechanical or biological prostheses. Both types positively contribute to restore the physiological function of native valves, but a number of drawbacks limits the expected performances. In order to improve the outcome, tissue engineering can offer an alternative approach to design and fabricate innovative heart valves capable to support the requested function and to promote the formation of a novel, viable and correctly operating physiological structure. This potential result is particularly critical if referred to the aortic valve, being the one mainly exposed to structural and functional degeneration. In this regard, the here proposed study presents the fabrication and in vitro characterization of a bioresorbable electrospun heart valve prosthesis using the particle image velocimetry technique either in physiological and pathological fluid dynamic conditions. The scaffold was designed to reproduce the aortic valve geometry, also mimicking the fibrous structure of the natural extracellular matrix. To evaluate its performances for possible implantation, the flow fields downstream the valve were accurately investigated and compared. The experimental results showed a correct functionality of the device, supported by the formation of vortex structures at the edge of the three cusps, with Reynolds stress values below the threshold for the risk of hemolysis (which can be comprised in the range 400-4000N/m(2) depending on the exposure period), and a good structural resistance to the mechanical loads generated by the driving pressure difference. Copyright © 2016 Elsevier Ltd. All rights reserved.

  10. Quantitative analysis of the relief in watersheds of the “El Ávila” massif northern hillside (Vargas State, Venezuela and its hydrogeomorphological meaning

    Williams José Méndez Mata


    analysis (DSA of morphometric parameters in Excel spreadsheets, based on the following statistics: maximum value, minimum value, mean, mode, median, variance, standard deviation, skewness, kurtosis, coefficient of variation, first quartile, second quartile and third quartile; (d linear correlation analysis (LCA between morphometric parameters, based on the application and estimation of the Pearson product-moment correlation using the MS Excel XLSTAT add-on software; and (e principal component analysis (PCA of morphometric parameters based on correlations, run with SPSS Statistics v. 17.0. The results show that the watersheds in the study area are conceived as exorheic hydrogeomorphological systems. Three relief units characteristic of these mountain environments systems were distinguished: catchment area, main drain channel and cone or alluvial fan, each with its own morphological features (landforms and distinctive geomorphological processes. Landforms were grouped into two major groups: on the one hand, those that result from the depositional activity of the main creeks and rivers, prevailing in valleys of the main drain channels and in foothills (alluvial fans; on the other, those that have been shaped by the erosive action associated with drainage networks, being observed mainly on hillsides. Creeks and rivers are waterways running along very short distances from headwaters to outputs on the mountain front, exhibiting pronounced changes in slope, usually steep. These are typical of torrential systems in mountainous environments with abrupt relief, favoring sudden hydrological responses. As regards the morphometric parameters of watershed relief and drainage networks, these were defined as topographically very rugged areas with steep slopes and steep altitudinal slopes. These morphometric parameters are typically represented by the slopes along the longitudinal profiles of the main creeks and rivers, and by the pronounced mountainous relief (massivity coefficient

  11. Simulation and experiment on static characteristic of water hydraulic proportional pressure relief valve%纯水比例溢流阀静态特性的仿真与试验

    张增猛; 周华; 高院安; 陈英龙


    A three-stage water hydraulic proportional pressure relief valve, with ball seat valve as the throttle control pilot stage, was investigated on the static characteristic. An AMESim model was built based on structure and mathematic analysis. The friction at spool, proportional electromagnetic actuator and steady flow force, which cause the valve hysteresis, were analyzed through simulation. The experiment results were also analyzed and compared to simulation results. The investigation shows that the large hysteresis mainly comes from flow force, hysteresis of electromagnetic actuator, and friction. Due to the static and coulomb friction and the structure of lever, the range of the input signal responding to pressure increasing section is narrower than pressure decreasing. The width of hysteresis is larger at low pressure than high pressure. For the reason of nonlinearity and large hysteresis of the valve, closed-loop control will be unstable and large oscillation may be induced. It should be improved through structure optimization or control compensation.%以带球阀比例节流先导级的三级座式纯水比例溢流阀为对象,在结构分析和数学建模的基础上,建立了阀的AMESim模型,仿真分析了稳态液动力、比例电磁铁、阀芯摩擦力等对阀静态特性的影响,并与试验对比. 结果表明:阀芯摩擦力及力放大杠杆结构降低了阀的静态性能,阀的滞环大,且随控制信号增大的可控线性段窄,阀在低压段的滞环大于高压工况. 阀的大滞环和严重的非线性降低了闭环系统稳定性,应通过改进结构和控制补偿等措施改善静态特性.

  12. Valve Disease

    ... heart valves, valve insufficiency, valve regurgitation, valve stenosis, valvular heart disease Every time your heart beats, blood flows into, ... removed from the market after being linked to heart valve disease. An infection in the lining of the heart's ...

  13. Dump valve assembly

    Owen, T.J.


    A dump valve assembly comprising a body having a bore defined by a tapered wall and a truncated spherical valve member adapted to seat along a spherical surface portion thereof against said tapered wall. Means are provided for pivoting said valve member between a closed position engagable with said tapered wall and an open position disengaged therefrom.

  14. 46 CFR 154.912 - Inerted spaces: Relief devices.


    ... 46 Shipping 5 2010-10-01 2010-10-01 false Inerted spaces: Relief devices. 154.912 Section 154.912... Atmospheric Control in Cargo Containment Systems § 154.912 Inerted spaces: Relief devices. Inerted spaces must be fitted with relief valves, rupture discs, or other devices specially approved by the...

  15. Analysis and Comparison of Rated Capacity Calculation of Safety Relief Valves for AP1000 Nuclear Project%AP1000核电项目安全释放阀额定排量计算的分析与比较

    陈中一; 徐陈凯


    安全释放阀[1]是一种通过排出一定量的介质来防止管道或设备内介质压力超过规定数值从而起到保护压力容器、管道和其它受压设备上的重要安全附件。正确的额定排量计算是安全阀的选用及系统保护设计的关键步骤。针对AP1000(第三代压水堆核电站的一种堆型)核电项目安全释放阀的多种排量计算标准进行了经验分析及比较。%The safety relief valve is a significant safety accessory for releasing a certain account of medium to protect pressure vessels, piping and other pressure containment equipment. Correct rated capacity calculation is the important step of safety re-lief valves selection and system protection design. Kinds of rated capacity calculation standards for the AP1000 nuclear project safety relief valves are analyzed and compared for the subsequent tests.

  16. 安全阀超压泄放过程动力学参数分析与测试%Analysis & testing on dynamic parameters of safety valve during the overpressure relief process

    郭崇志; 姚远


    对3D模型安全阀的超压泄放机理及气体动力学过程进行了模拟分析和试验验证。利用区域分组法和路径分析法,对开启部件在超压泄放过程中的稳态流场参数进行了详细整理,研究了速度、压力参数在内外流场选定路径上的分布以及开启部件的动态力平衡情况。对竖直(Y)方向各种力平衡问题的研究和比较,证明了升力测试值为总力,包括静态力和动态力两部分,其中,静态力占绝对优势;反冲(升)力中,动态力起很大作用,间隙力属于自平衡力系。动态力主要来源于密封面和反冲盘折边出口附近的高速气体流动。阀芯反冲(升)力也主要来源于静态力,动态力影响较小。水平(X)方向力平衡参数研究结果表明,对于反冲盘与阀芯分离结构,阀芯处于严格的动态平衡中,而反冲盘则可能存在水平方向的不平衡力,可能导致阀芯开启和回座过程偏载。无论阀芯与反冲盘是整体还是分离式设计,此偏载均可能导致开启回座偏差,甚至引发颤振、频跳或密封面损坏。利用试验装置和新研制的传感器,获取了试验开启过程中阀芯压力、升力、开启高度和反冲盘测点压力,进一步计算了反冲盘和阀芯反冲(升)力的数值。试验和模拟结果对比表明,数值模拟结果与传感器测试数据吻合,为进一步研究内外流场及其动作机理奠定了基础。%With the numerical simulation and the experiment methods,the safety valve overpressure relief process and the gas dynamic problem are studied. The relief valve interior steady flow field of moving parts was analyzed by using the domain decomposition and paths analysis methods,the dynamic force balance,the distribution of velocity and the stress characteristics of the paths in the interior and external flow field were studied as well. The results showed that according to the

  17. Increasing the Useful Life of Quench Reliefs with Inconel Bellows

    Soyars, W. M. [Fermilab


    Reliable quench relief valves are an important part of superconducting magnet systems. Fermilab developed bellows-actuated cryogenic quench reliefs which have been in use since the early l 980's. The original design uses a stainless steel bellows. A high frequency, low amplitude vibration during relieving events has resulted in fatigue failures in the original design. To take advantage of the improved resistance to fatigue of Inconel, a nickel-chromium alloy, reliefs using Inconel 625 bellows were made. Design, development, and testing of the new version reliefs will be discussed. Tests show that relief valve lifetimes using Inconel bellows are more than five times greater than when using the original stainless steel bellows. Inconel bellows show great promise in increasing the lifetime of quench relief valves, and thus the reliability of accelerator cryogenic systems.

  18. Out of the wave: The meaning of suffering and relief from suffering as described in autobiographies by survivors of the 2004 Indian Ocean tsunami

    Åsa Roxberg


    Full Text Available The aim of this study was to explore the meaning of suffering and relief from suffering as described in autobiographies by tourists who experienced the tsunami on 26 December 2004 and lost loved ones. A lifeworld approach, inspired by the French philosopher Merleau-Ponty's phenomenology of perception, was chosen for the theoretical framework. This catastrophe totally changed the survivors’ world within a moment. In this new world, there were three main phases: the power of remaining focused, a life of despair, and the unbearable becoming bearable. Life turns into a matter of making the unbearable bearable. Such challenging experiences are discussed in terms of the philosophy of Weil, Jaspers, and Merleau-Ponty. The survivors of the tsunami catastrophe were facing a boundary situation and “le malheur,” the unthinkable misfortune. Even at this lowest level of misfortune, joy is possible to experience. This is part of the survivors’ ambivalent experiences of their lifeworld. In this world of the uttermost despair there are also rays of hope, joy, and new life possibilities.

  19. Out of the wave: The meaning of suffering and relief from suffering as described in autobiographies by survivors of the 2004 Indian Ocean tsunami.

    Roxberg, Asa; Sameby, Jessica; Brodin, Sandra; Fridlund, Bengt; da Silva, António Barbosa


    The aim of this study was to explore the meaning of suffering and relief from suffering as described in autobiographies by tourists who experienced the tsunami on 26 December 2004 and lost loved ones. A lifeworld approach, inspired by the French philosopher Merleau-Ponty's phenomenology of perception, was chosen for the theoretical framework. This catastrophe totally changed the survivors' world within a moment. In this new world, there were three main phases: the power of remaining focused, a life of despair, and the unbearable becoming bearable. Life turns into a matter of making the unbearable bearable. Such challenging experiences are discussed in terms of the philosophy of Weil, Jaspers, and Merleau-Ponty. The survivors of the tsunami catastrophe were facing a boundary situation and "le malheur," the unthinkable misfortune. Even at this lowest level of misfortune, joy is possible to experience. This is part of the survivors' ambivalent experiences of their lifeworld. In this world of the uttermost despair there are also rays of hope, joy, and new life possibilities.

  20. Depth relief

    Kappers, A.M.L.; Koenderink, J.J.; Doorn, A.J. van


    A study is reported of the depth relief in a simple three-dimensional scene consisting of a white, rough sphere on a planar support, illuminated in a natural manner. Viewing conditions included monocular and binocular as well as 'synoptical' viewing. In the synoptical condition the eyes are

  1. 14 CFR 125.137 - Oil valves.


    ... 14 Aeronautics and Space 3 2010-01-01 2010-01-01 false Oil valves. 125.137 Section 125.137....137 Oil valves. (a) Each oil valve must— (1) Comply with § 125.155; (2) Have positive stops or... the valve. (b) The closing of an oil shutoff means must not prevent feathering the propeller,...

  2. Valve stem and packing assembly

    Wordin, J.J.


    A valve stem and packing assembly is provided in which a rotatable valve stem includes a first tractrix surface for sliding contact with a stem packing and also includes a second tractrix surface for sliding contact with a bonnet. Force is applied by means of a spring, gland flange, and gland on the stem packing so the stem packing seals to the valve stem and bonnet. This configuration serves to create and maintain a reliable seal between the stem packing and the valve stem. The bonnet includes a second complementary tractrix surface for contacting the second sliding tractrix surface, the combination serving as a journal bearing for the entire valve stem and packing assembly. The journal bearing so configured is known as a Schiele`s pivot. The Schiele`s pivot also serves to maintain proper alignment of the valve stem with respect to the bonnet. Vertical wear between the surfaces of the Schiele`s pivot is uniform at all points of contact between the second sliding tractrix surface and the second complementary tractrix surface of a bonnet. The valve stem is connected to a valve plug by means of a slip joint. The valve is opened and closed by rotating the valve stem. The slip joint compensates for wear on the Schiele`s pivot and on the valve plug. A ledge is provided on the valve bonnet for the retaining nut to bear against. The ledge prevents overtightening of the retaining nut and the resulting excessive friction between stem and stem packing.

  3. Digital relief generation from 3D models

    Wang, Meili; Sun, Yu; Zhang, Hongming; Qian, Kun; Chang, Jian; He, Dongjian


    It is difficult to extend image-based relief generation to high-relief generation, as the images contain insufficient height information. To generate reliefs from three-dimensional (3D) models, it is necessary to extract the height fields from the model, but this can only generate bas-reliefs. To overcome this problem, an efficient method is proposed to generate bas-reliefs and high-reliefs directly from 3D meshes. To produce relief features that are visually appropriate, the 3D meshes are first scaled. 3D unsharp masking is used to enhance the visual features in the 3D mesh, and average smoothing and Laplacian smoothing are implemented to achieve better smoothing results. A nonlinear variable scaling scheme is then employed to generate the final bas-reliefs and high-reliefs. Using the proposed method, relief models can be generated from arbitrary viewing positions with different gestures and combinations of multiple 3D models. The generated relief models can be printed by 3D printers. The proposed method provides a means of generating both high-reliefs and bas-reliefs in an efficient and effective way under the appropriate scaling factors.

  4. Reducing leaks in water distribution networks. Controlling pressure by means of automatic hydraulic valves; Reduccion de fugas en redes de distribucion de agua. Control de la presion mediante valvulas hidraulicas automaticas

    Singla Font, S.


    Any water distribution network, bet it of drinking water or irrigation water, always loses an inevitable amount. One of the main ways to reduce leaks is to optimise the pressure in the network by means of hydraulic valves with different types of control devices. These can be either completely hydraulic or supplemented by electronic systems. (Author)

  5. 33 CFR 157.122 - Piping, valves, and fittings.


    ...) Each overpressure relief valve must discharge into the suction side of a pump that meets § 157.126(b... system for oil washing and water washing, that piping system must be designed to drain the crude oil...

  6. Valve-"Health"-Monitoring System

    Jensen, Scott L.; Drouant, George J.


    A system that includes sensors and data acquisition, wireless data-communication, and data-processing subsystems has been developed as a means of both real-time and historical tracking of information indicative of deterioration in the mechanical integrity and performance of a highgeared ball valve or a linearly actuated valve that operates at a temperature between cryogenic and ambient.

  7. Valve stem and packing assembly

    Wordin, J.J.


    A valve stem and packing assembly is provided in which a rotatable valve stem includes a first tractrix surface for sliding contact with a stem packing and also includes a second tractrix surface for sliding contact with a bonnet. Force is applied by means of a spring, gland flange, and gland on the stem packing so the stem packing seals to the valve stem and bonnet. This configuration serves to create and maintain a reliable seal between the stem packing and the valve stem. The bonnet includes a second complementary tractrix surface for contacting the second sliding tractrix surface, the combination serving as a journal bearing for the entire valve stem and packing assembly. The journal bearing so configured is known as a Schiele's pivot. The Schiele's pivot also serves to maintain proper alignment of the valve stem with respect to the bonnet. Vertical wear between the surfaces of the Schiele's pivot is uniform at all points of contact between the second sliding tractrix surface and the second complementary tractrix surface of a bonnet. The valve stem is connected to a valve plug by means of a slip joint. The valve is opened and closed by rotating the valve stem. The slip joint compensates for wear on the Schiele's pivot and on the valve plug. A ledge is provided on the valve bonnet for the retaining nut to bear against. The ledge prevents over tightening of the retaining nut and the resulting excessive friction between stem and stem packing. 2 figures.

  8. Valve stem and packing assembly

    Wordin, John J. (Bingham County, ID)


    A valve stem and packing assembly is provided in which a rotatable valve stem includes a first tractrix surface for sliding contact with a stem packing and also includes a second tractrix surface for sliding contact with a bonnet. Force is applied by means of a spring, gland flange, and gland on the stem packing so the stem packing seals to the valve stem and bonnet. This configuration serves to create and maintain a reliable seal between the stem packing and the valve stem. The bonnet includes a second complementary tractrix surface for contacting the second sliding tractrix surface, the combination serving as a journal bearing for the entire valve stem and packing assembly. The journal bearing so configured is known as a Schiele's pivot. The Schiele's pivot also serves to maintain proper alignment of the valve stem with respect to the bonnet. Vertical wear between the surfaces of the Schiele's pivot is uniform at all points of contact between the second sliding tractrix surface and the second complementary tractrix surface of a bonnet. The valve stem is connected to a valve plug by means of a slip joint. The valve is opened and closed by rotating the valve stem. The slip joint compensates for wear on the Schiele's pivot and on the valve plug. A ledge is provided on the valve bonnet for the retaining nut to bear against. The ledge prevents overtightening of the retaining nut and the resulting excessive friction between stem and stem packing.

  9. Valve stem and packing assembly

    Wordin, J.J.


    A valve stem and packing assembly is provided in which a rotatable valve stem includes a first tractrix surface for sliding contact with a stem packing and also includes a second tractrix surface for sliding contact with a bonnet. Force is applied by means of a spring, gland flange, and gland on the stem packing so the stem packing seals to the valve stem and bonnet. This configuration serves to create and maintain a reliable seal between the stem packing and the valve stem. The bonnet includes a second complementary tractrix surface for contacting the second sliding tractrix surface, the combination serving as a journal bearing for the entire valve stem and packing assembly. The journal bearing so configured is known as a Schiele's pivot. The Schiele's pivot also serves to maintain proper alignment of the valve stem with respect to the bonnet. Vertical wear between the surfaces of the Schiele's pivot is uniform at all points of contact between the second sliding tractrix surface and the second complementary tractrix surface of a bonnet. The valve stem is connected to a valve plug by means of a slip joint. The valve is opened and closed by rotating the valve stem. The slip joint compensates for wear on the Schiele's pivot and on the valve plug. A ledge is provided on the valve bonnet for the retaining nut to bear against. The ledge prevents overtightening of the retaining nut and the resulting excessive friction between stem and stem packing.

  10. 14 CFR 25.995 - Fuel valves.


    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Fuel valves. 25.995 Section 25.995... STANDARDS: TRANSPORT CATEGORY AIRPLANES Powerplant Fuel System Components § 25.995 Fuel valves. In addition to the requirements of § 25.1189 for shutoff means, each fuel valve must— (a) (b) Be supported...

  11. Tricuspid Valve Replacement, Mechnical vs. Biological Valve, Which Is Better?

    Haitham Akram Altaani


    Full Text Available Background: The initial trial in tricuspid surgery is repair; however, replacement is done whenever the valve is badly diseased. Tricuspid valve replacement comprises 1.7% of all tricuspid valve surgeries. Materials and Methods: The present retrospective study was performed using the medical records of 21 cases who underwent tricuspid valve replacement from January 2002 until the end of December 2010. The mean age of the participants was 52.3±8.8 years and 66.7% were females. In addition, tricuspid valve replacement was associated with mitral valve surgery, aortic valve surgery, and both in 14.3%, 4.8%, and 33.3% of the cases, respectively. Yet, isolated tricuspid valve replacement and redo surgery were performed in 10 cases (47.6% and 8 cases (38.1%, respectively. Besides, trial of repair was done in 14 cases (66.7%. Moreover, biological and mechanical valves were used in 76.2% and 23.8% of the patients, respectively. Results: According to the results, early mortality was 23.8% and one year survival was 66.7%. Moreover, early mortality was caused by right ventricular failure, multiorgan failure, medistinitis, and intracerbral bleeding in 42%, 28.6%, 14.3%, and 14.3% of the cases, respectively. In addition, 57.1% of the deaths had occurred in the cases where the biological valve was used, while 42.9% of the deaths had taken place where the mechanical one was utilized. Conclusions: The patients who require tricuspid valve replacement are usually high risk surgical candidates with early and long term mortality. The findings of the current study showed no significant hemodynamic difference between mechanical and biological valves.

  12. Itching for Allergy Relief?

    ... Home For Consumers Consumer Updates Itching for Allergy Relief? Share Tweet Linkedin Pin it More sharing options ... your ability to function, you don't find relief from OTC drugs, or you experience allergy symptoms ...

  13. Elastodynamic analysis of the desmodromic valve train of a racing motorbike engine by means of a combined lumped/finite element model

    Rivola, A.; Troncossi, M.; Dalpiaz, G.; Carlini, A.


    A combined lumped/finite element model of a portion of the desmodromic valve train of a racing motorbike engine was developed and validated in order to simulate the elastodynamic behaviour of such a particular timing system. The model includes the lumped parameter model of the belt transmission that drives the camshafts, the finite element model of the camshafts, and the lumped parameter model of two cam-valve mechanisms (one for each camshaft). The procedure to validate the model, based on experimental tests carried out on a test bench described here, is presented and discussed. The comparison between the numerical results and the experimental data shows that the effectiveness of the model is satisfactorily achieved. It will be possible, in a further study, to add the other cam-valve mechanisms and the missing external forces, in order to obtain a complete system model. Some possible applications of the presented model are provided in order to show how the overall model could be employed to perform both design optimisation and diagnostics.

  14. EC Hidraulic Drive Cylinder Relief Vlave Test

    Wu, J.; /Fermilab


    This engineering note documents the testing of the set pressure of the EC hydraulic drive cylinder relief valve. The purpose of the relief valve is to provide a safety measure in the event that oil becomes trapped in the rod side of the cylinder and pressure is applied to the cap side. The note includes an explanation of the procedure used and a summary of the result of the testing done on February 14, 1991 by Gary Trotter. The result was that the cylinder relief valve relieved at the correct set pressure of 10,500 psig. The basic concern is for the protection of the cylinder. The pump is capable of providing up to 10,500 psi of pressure to either side of the cylinder. The cylinder is rated for 10,500 psi. Under normal operating conditions, the valves would be open, and the pumping pressure would automatically flow oil into one side, and remove oil from the other side. If, however, the valve for the other side was closed, so that oil could not be removed, then the pressure would build in that side. If the rod side is pressurized to the maximum pump pressure of 10,500 psi, the cross sectional area ratio of 2.29 results in a pressure of approximately 4600 psi in the cap side, which is well under the rated pressure. If, however, the cap side is pressurized to 10,500 psi, the cross sectional area would produce a pressure of approximately 24,000 psi in the rod side, which could damage the cylinder. Therefore, the pressure on the rod side must be limited to the rated pressure of 10,500 psi. In reality, the maximum operating force on the piston would be under 11,000 Ibs., which would result in the maximum cylinder pressure being under 8000 psi to the rod side, and under 3500 psi to the cap side. Therefore, the relief is only needed as a safety precaution in the case that oil becomes trapped.

  15. 49 CFR 236.383 - Valve locks, valves, and valve magnets.


    ... 49 Transportation 4 2010-10-01 2010-10-01 false Valve locks, valves, and valve magnets. 236.383... Inspection and Tests § 236.383 Valve locks, valves, and valve magnets. Valve locks on valves of the non-cut-off type shall be tested at least once every three months, and valves and valve magnets shall...

  16. Piezoelectric valve

    Petrenko, Serhiy Fedorovich


    A motorized valve has a housing having an inlet and an outlet to be connected to a pipeline, a saddle connected with the housing, a turn plug having a rod, the turn plug cooperating with the saddle, and a drive for turning the valve body and formed as a piezoelectric drive, the piezoelectric drive including a piezoelectric generator of radially directed standing acoustic waves, which is connected with the housing and is connectable with a pulse current source, and a rotor operatively connected with the piezoelectric generator and kinematically connected with the rod of the turn plug so as to turn the turn plug when the rotor is actuated by the piezoelectric generator.

  17. Excess flow shutoff valve

    Kiffer, Micah S.; Tentarelli, Stephen Clyde


    Excess flow shutoff valve comprising a valve body, a valve plug, a partition, and an activation component where the valve plug, the partition, and activation component are disposed within the valve body. A suitable flow restriction is provided to create a pressure difference between the upstream end of the valve plug and the downstream end of the valve plug when fluid flows through the valve body. The pressure difference exceeds a target pressure difference needed to activate the activation component when fluid flow through the valve body is higher than a desired rate, and thereby closes the valve.

  18. Vacuum Valve


    This valve was used in the Intersecting Storage Rings (ISR) to protect against the shock waves that would be caused if air were to enter the vacuum tube. Some of the ISR chambers were very fragile, with very thin walls - a design required by physicists on the lookout for new particles.

  19. Valve's Way

    Foss, Nicolai Juul; Dobrajska, Magdalena


    to what extent it represents a new blueprint for organization design, despite it being consistent with an “egalitarian Zeitgeist” (Puranam, 2014). In fact, managerial authority may be of increasing importance rather than the opposite (Guadalupe, Li, & Wulf, 2015). Thus, Valve is, and will remain...

  20. Valve's Way

    Foss, Nicolai Juul; Dobrajska, Magdalena


    Puranam and Håkonsson (2015) challenge us to ponder what we as organization design theorists make of Valve’s way (see also Jeppesen, 2008). We believe that Valve, in spite of its radical vision, does not represent a challenge to fundamental organization design theory and that it is questionable...

  1. 46 CFR 53.05-1 - Safety valve requirements for steam boilers (modifies HG-400 and HG-401).


    ... 46 Shipping 2 2010-10-01 2010-10-01 false Safety valve requirements for steam boilers (modifies HG... requirements for steam boilers (modifies HG-400 and HG-401). (a) The pressure relief valve requirements and the safety valve requirements for steam boilers must be as indicated in HG-400 and HG-401 of section IV...

  2. Percutaneous implantation of CoreValve aortic prostheses in patients with a mechanical mitral valve.

    Bruschi, Giuseppe; De Marco, Federico; Oreglia, Jacopo; Colombo, Paola; Fratto, Pasquale; Lullo, Francesca; Paino, Roberto; Frigerio, Maria; Martinelli, Luigi; Klugmann, Silvio


    Concerns exist in the field of transcatheter aortic valve implantation regarding the treatment of patients with mechanical mitral valve for possible interference between the percutaneous aortic valve and the mechanical mitral prosthesis. We report our experience with percutaneous aortic valve implantation in 4 patients with severe aortic stenosis, previously operated on for mitral valve replacement with a mechanical prosthesis. All patients underwent uneventful percutaneous retrograde CoreValve implantation (CoreValve Inc, Irvine, CA). No deformation of the nitinol tubing of the prostheses (ie, neither distortion nor malfunction of the mechanical valve in the mitral position) occurred in any of the patients. All patients are alive and asymptomatic at a mean follow-up of 171 days.

  3. Aortic valve bypass

    Lund, Jens T; Jensen, Maiken Brit; Arendrup, Henrik


    In aortic valve bypass (AVB) a valve-containing conduit is connecting the apex of the left ventricle to the descending aorta. Candidates are patients with symptomatic aortic valve stenosis rejected for conventional aortic valve replacement (AVR) or transcatheter aortic valve implantation (TAVI...

  4. Robotic mitral valve replacement.

    Senay, Sahin; Gullu, Ahmet Umit; Kocyigit, Muharrem; Degirmencioglu, Aleks; Karabulut, Hasan; Alhan, Cem


    Robotic surgical techniques allow surgeons to perform mitral valve surgery. This procedure has gained acceptance, particularly for mitral valve repair in degenerative mitral disease. However, mitral repair may not always be possible, especially in severely calcified mitral valve of rheumatic origin. This study demonstrates the basic concepts and technique of robotic mitral valve replacement for valve pathologies that are not suitable for repair.

  5. Menopause: Symptom Relief and Treatments

    ... Submit Home > Menopause > Menopause symptom relief and treatments Menopause Menopause symptom relief and treatments Working with your doctor ... on menopause symptom relief and treatments Learning about menopause treatment options Most women do not need treatment ...

  6. Transaortic aortic valve replacement using the Edwards Sapien-XT Valve and the Medtronic CoreValve: initial experience.

    Spargias, Konstantinos; Bouboulis, Nikolaos; Halapas, Antonios; Chrissoheris, Michael; Skardoutsos, Spyridon; Nikolaou, Joulia; Tsolakis, Apostolos; Mourmouris, Christos; Pattakos, Stratis


    Transcatheter aortic valve replacement (TAVR) is now an established treatment for certain patients with severe aortic valve stenosis (AS). However, as the number of patients screened for TAVR increases, many are found to have absolutely no option for peripheral artery access. Transaortic valve replacement (TAoVR) has been proposed as a new alternative route in patients deemed unsuitable for conventional approaches. We present our first series of TAoVR cases using the Edwards Sapien-XT and the Medtronic CoreValve prostheses. Twenty-five (25) symptomatic patients (mean age 78 ± 8 years, mean logistic EuroSCORE I 25 ± 11%) with severe AS underwent TAoVR using the Sapien-XT valve (10 patients) or the CoreValve (15 patients). The mean fluoroscopy time was 15.6 ± 4.2 minutes, the mean time in the intensive care unit was 1.9 ± 1.0 days, and the mean hospital stay was 6.4 ± 1.6 days. The mean effective aortic valve area increased (from 0.68 ± 0.15 cm(2) to 1.82 ± 0.34 cm(2), pMedtronic CoreValve prosthesis demonstrated that it could be performed safely, resulting in substantial acute echocardiographic and early clinical improvement.

  7. Minimally invasive aortic valve replacement

    Foghsgaard, Signe; Schmidt, Thomas Andersen; Kjaergard, Henrik K


    In this descriptive prospective study, we evaluate the outcomes of surgery in 98 patients who were scheduled to undergo minimally invasive aortic valve replacement. These patients were compared with a group of 50 patients who underwent scheduled aortic valve replacement through a full sternotomy....... The 30-day mortality rate for the 98 patients was zero, although 14 of the 98 mini-sternotomies had to be converted to complete sternotomies intraoperatively due to technical problems. Such conversion doubled the operative time over that of the planned full sternotomies. In the group of patients whose...... is an excellent operation in selected patients, but its true advantages over conventional aortic valve replacement (other than a smaller scar) await evaluation by means of randomized clinical trial. The "extended mini-aortic valve replacement" operation, on the other hand, is a risky procedure that should...



    An active valve for use e.g. in fluidic microsystems is provided, wherein the active valve comprises a membrane having at least one flow gate, arranged between a first and a second substantially rigid element. Adjusting means provides an adjustment of the clamping force on membrane arranged between...... the first and second substantially rigid element. Hereby the flow rate through the active valve can be continuously and precisely controlled....

  9. Automatic shutoff valve

    Hawkins, S. F.; Overbey, C. W.


    Cellulose-sponge disk absorbs incoming water and expands with enough force to shut valve. When water recedes, valve opens by squeezing sponge dry to its original size. This direct mechanical action is considered more reliable than solenoid valve.

  10. An analysis of check valve performance characteristics based on valve design

    McElhaney, K.L. [Oak Ridge National Lab., TN (United States). Engineering Technology Div.


    Although it had been theorized by nuclear industry valve experts that the two most significant factors in assessing check valve performance were valve type (or design) and operating conditions, until recently, no data was available to support their assumptions. In co-operation with the Nuclear Industry Check Valve Group (NIC), Oak Ridge National Laboratory (ORNL) undertook a review and analysis of check valve failures recorded in the Institute of Nuclear Power Operations' (INPO) Nuclear Plant Reliability Data System (NPRDS). This study involved the characterization of failures according to several parameters, including valve design (e.g. swing check, lift check). Since the valve design is not inherently included within the NPRDS engineering record for each component in the database, ORNL relied on input from NIC, valve manufacturers and catalogs to supply the missing information. As a result, nearly 60% of the 21000 check valves listed in the NPRDS component database and 85% of the 838 failures occurring during 1991-1992 were identified according to valve design. This data provided the basis to perform previously unavailable cross-correlations between parameters such as valve design versus failure mode, valve design versus failure discovery method, population/failure distributions by valve design, etc. Performance assessments and predictions based on more specific sets of parameters (as opposed to generic check valve failure rates obtained from standard reference sources that generally ignore the valve design) should result in a significant impact on future nuclear plant operations, including inservice testing (IST) practices, maintenance, and probabilistic risk assessments (PRAs) by providing a means to calculate more appropriate relative (and ultimately absolute) failure rates for check valves. (orig.)

  11. Late-Cenozoic relief evolution under evolving climate: a review

    Champagnac, Jean-Daniel; Valla, Pierre; Herman, Fred


    The present review is an attempt to summarize quantitative evidence of Late Cenozoic changes in topographic relief on Earth. We first define different meanings of the word "relief", as it is commonly used, and detail the metrics used to quantify it. We then specify methodological tools used to quantify relief change (primarily lowtemperature thermochronometry and terrestrial cosmogenic nuclides), and analyze published evidence for different regions. Our review first show that relief changes and rates of changes are more important at mid-, than high- or low-latitudes, and appear to be insensitive to mean precipitation rates. We also show that relief change is positive (relief increases) in most of the reported cases (~80%). We subsequently define two functional relationships between relief and erosion, depending on the chosen definition of relief, and propose a conceptual model of landscape memory. We conclude, following others, that erosion rates depends non-linearly on relief evolution, itself being a function of the spatial distribution and rates of erosion. The relief increases documented in this review may be related led to erosion rate increases during the same timescales. Lastly, we discuss the importance of glacial and periglacial processes on Late Cenozoic relief and erosion rate changes, and stress the importance of frost shattering and glacial erosion at mid- and high-latitudes.

  12. Study on high reliability safety valve for railway vehicle

    Zhang, Xuan; Chen, Ruikun; Zhang, Shixi; Xu, BuDu


    Now, the realization of most of the functions of the railway vehicles rely on compressed air, so the demand for compressed air is growing higher and higher. This safety valve is a protection device for pressure limitation and pressure relief in an air supply system of railway vehicles. I am going to introduce the structure, operating principle, research and development process of the safety valve designed by our company in this document.

  13. 40 CFR 63.169 - Standards: Pumps, valves, connectors, and agitators in heavy liquid service; instrumentation...


    ..., and agitators in heavy liquid service; instrumentation systems; and pressure relief devices in liquid...: Pumps, valves, connectors, and agitators in heavy liquid service; instrumentation systems; and pressure..., pressure relief devices in light liquid or heavy liquid service, and instrumentation systems shall...

  14. Valve-in-valve-in-valve: Treating endocarditis of a transcatheter heart valve.

    Nguyen, Caroline; Cheong, Adrian P; Himbert, Dominique


    Transcatheter heart valve endocarditis is a rare, but life threatening complication. We describe the case of a patient who was successfully treated by transcatheter aortic valve-in-valve-in-valve replacement with a favorable 1-year outcome, despite severe early complications.

  15. Microfluidic sieve valves

    Quake, Stephen R; Marcus, Joshua S; Hansen, Carl L


    Sieve valves for use in microfluidic device are provided. The valves are useful for impeding the flow of particles, such as chromatography beads or cells, in a microfluidic channel while allowing liquid solution to pass through the valve. The valves find particular use in making microfluidic chromatography modules.

  16. Remote actuated valve implant

    McKnight, Timothy E.; Johnson, Anthony; Moise, Kenneth J.; Ericson, Milton Nance; Baba, Justin S.; Wilgen, John B.; Evans, Boyd Mccutchen


    Valve implant systems positionable within a flow passage, the systems having an inlet, an outlet, and a remotely activatable valve between the inlet and outlet, with the valves being operable to provide intermittent occlusion of the flow path. A remote field is applied to provide thermal or magnetic activation of the valves.

  17. 14 CFR 23.995 - Fuel valves and controls.


    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Fuel valves and controls. 23.995 Section 23... Components § 23.995 Fuel valves and controls. (a) There must be a means to allow appropriate flight crew members to rapidly shut off, in flight, the fuel to each engine individually. (b) No shutoff valve may...


    LIM CC


    Full Text Available Nasal foreign body in children is not an uncommon presentation to the Emergency Department. Removal is essential. Many methods of removal exist. Nasal wash technique is advocated mainly in friable foreign bodies. We report the successful use of the oral bag-valve-mask insufflation technique to remove friable facial tissue in the left nose of a 2 year-old girl. We used a pediatric bag-valve-mask with a pop-off pressure relief valve to avoid barotrauma. Pop-off pressure relief valve limits the pressure beyond 30mmHg. Conscious sedation was not required. There were no complications.

  19. Scissor thrust valve actuator

    DeWall, Kevin G.; Watkins, John C; Nitzel, Michael E.


    Apparatus for actuating a valve includes a support frame and at least one valve driving linkage arm, one end of which is rotatably connected to a valve stem of the valve and the other end of which is rotatably connected to a screw block. A motor connected to the frame is operatively connected to a motor driven shaft which is in threaded screw driving relationship with the screw block. The motor rotates the motor driven shaft which drives translational movement of the screw block which drives rotatable movement of the valve driving linkage arm which drives translational movement of the valve stem. The valve actuator may further include a sensory control element disposed in operative relationship with the valve stem, the sensory control element being adapted to provide control over the position of the valve stem by at least sensing the travel and/or position of the valve stem.

  20. Valve-in-Valve Replacement Using a Sutureless Aortic Valve

    Dohmen, Pascal M.; Lehmkuhl, Lukas; Borger, Michael A.; Misfeld, Martin; Mohr, Friedrich W.


    Patient: Female, 61 Final Diagnosis: Tissue degeneration Symptoms: Dyspnea Medication: — Clinical Procedure: Redo valve replacement Specialty: Surgery Objective: Rare disease Background: We present a unique case of a 61-year-old female patient with homograft deterioration after redo surgery for prosthetic valve endocarditis with root abscess. Case Report: The first operation was performed for type A dissection with root, arch, and elephant trunk replacement of the thoracic aorta. The present re-redo surgery was performed as valve-in-valve with a sutureless aortic biopros-thesis. The postoperative course was uneventful and the patient was discharged on day 6. Conclusions: The current case report demonstrates that sutureless bioprostheses are an attractive option for surgical valve-in-valve procedures, which can reduce morbidity and mortality. PMID:27694795

  1. Study of relief systems behavior in shipping terminals; Estudo do comportamento de sistemas de alivio em dutos de terminais maritimos

    Pires, Luis F.G.; Ladeia, Renata C. da Cunha; Ortega Malca, Arturo J. [Pontificia Univ. Catolica do Rio de Janeiro, RJ (Brazil). Dept. de Engenharia Mecanica. Nucleo de Simulacao Termohidraulica de Dutos (SIMDUT); Kossatz, Helmut [TRANSPETRO - PETROBRAS Transporte S.A., Rio de Janeiro, RJ (Brazil)


    In order to reduce operational costs, maritime terminals work with high flows transferring product between ships and in shore tanks. To protect the pipeline from any hydraulic transient, relief systems are commonly installed in strategic positions. During the project stage, computational simulation is widely used as auxiliary tool to determine the kind of valve and the place where the relief system must be installed. The present work points out the importance of the kind of valve chosen and its location along the pipeline, and shows that these factors affect directly the surge pressure produced by the valve closure. Besides, it compares a conventional spring-loaded relief valve behavior to a rupture disc one, making use of commercial program tools and employing a model based on the method of the characteristics. (author)

  2. Automatic device for maintenance on safety relief valve

    Fujio, M. [Okano Valve Mfg. Co. Ltd., Kitakyushu, Fukuoka (Japan)


    This system offers shorter, labor-saving periodic inspection of nuclear power plants particularly for maintenance of in the BWR plant. This automatic device has the following performance features. (author).

  3. Relief Aid Carefully Audited


    In a recent interview with the national TV broadcaster CCTV,Wang Zhongxin,Director of the Social Security Audit Department at the National Audit Office,talks about the procedures that are in effect to ensure relief supplies for the Wenchuan earthquake victims reach the end users. Excerpts of

  4. Paper relief architecture

    Latka, J.F.


    The article presents two contemporary projects of paper structures relief architecture designed and built by Shigeru Ban Architects and Voluntary Architect Network. Author of the article took part in design and construction process of one of the projects. The project of Yaan Nursery School, which wa

  5. Which valve is which?

    Pravin Saxena


    Full Text Available A 25-year-old man presented with a history of breathlessness for the past 2 years. He had a history of operation for Tetralogy of Fallot at the age of 5 years and history suggestive of Rheumatic fever at the age of 7 years. On echocardiographic examination, all his heart valves were severely regurgitating. Morphologically, all the valves were irreparable. The ejection fraction was 35%. He underwent quadruple valve replacement. The aortic and mitral valves were replaced by metallic valve and the tricuspid and pulmonary by tissue valve.

  6. Allergy Relief for Your Child

    ... For Consumers Home For Consumers Consumer Updates Allergy Relief for Your Child Share Tweet Linkedin Pin it ... counter (OTC) and prescription medicines that offer allergy relief as well as allergen extracts used to diagnose ...

  7. Finding Relief from Allergy's Grip

    ... Navigation Bar Home Current Issue Past Issues Finding Relief from Allergy's Grip Past Issues / Summer 2006 Table ... action for patients who have had inadequate symptom relief with antihistamines and topical nasal steroids. Through injection ...

  8. Statins for aortic valve stenosis

    Luciana Thiago

    Full Text Available ABSTRACT BACKGROUND: Aortic valve stenosis is the most common type of valvular heart disease in the USA and Europe. Aortic valve stenosis is considered similar to atherosclerotic disease. Some studies have evaluated statins for aortic valve stenosis. OBJECTIVES: To evaluate the effectiveness and safety of statins in aortic valve stenosis. METHODS: Search methods: We searched the Cochrane Central Register of Controlled Trials (CENTRAL, MEDLINE, Embase, LILACS - IBECS, Web of Science and CINAHL Plus. These databases were searched from their inception to 24 November 2015. We also searched trials in registers for ongoing trials. We used no language restrictions. Selection criteria: Randomized controlled clinical trials (RCTs comparing statins alone or in association with other systemic drugs to reduce cholesterol levels versus placebo or usual care. Data collection and analysis: Primary outcomes were severity of aortic valve stenosis (evaluated by echocardiographic criteria: mean pressure gradient, valve area and aortic jet velocity, freedom from valve replacement and death from cardiovascular cause. Secondary outcomes were hospitalization for any reason, overall mortality, adverse events and patient quality of life. Two review authors independently selected trials for inclusion, extracted data and assessed the risk of bias. The GRADE methodology was employed to assess the quality of result findings and the GRADE profiler (GRADEPRO was used to import data from Review Manager 5.3 to create a 'Summary of findings' table. MAIN RESULTS: We included four RCTs with 2360 participants comparing statins (1185 participants with placebo (1175 participants. We found low-quality evidence for our primary outcome of severity of aortic valve stenosis, evaluated by mean pressure gradient (mean difference (MD -0.54, 95% confidence interval (CI -1.88 to 0.80; participants = 1935; studies = 2, valve area (MD -0.07, 95% CI -0.28 to 0.14; participants = 127; studies = 2

  9. Aortic Valve Regurgitation

    ... inside your heart that involves heart valves. Rheumatic fever. Rheumatic fever — a complication of strep throat and once a ... the United States — can damage the aortic valve. Rheumatic fever is still prevalent in developing countries but rare ...

  10. Pulmonary Valve Stenosis

    ... growths called carcinoid tumors in the digestive system. Rheumatic fever. This complication of an infection caused by streptococcus ... valve stenosis later in life, including: Carcinoid syndrome Rheumatic fever Noonan's syndrome Mild to moderate pulmonary valve stenosis ...

  11. Aortic Valve Disease

    ... Tricuspid Valve Disease Cardiac Rhythm Disturbances Thoracic Aortic Aneurysm Pediatric and Congenital Heart Disease Heart abnormalities that are ... Transplantation End-stage Lung Disease Adult Lung Transplantation Pediatric Lung ... Aortic Aneurysm Aortic Valve Disease Overview The human heart has ...

  12. Mitral Valve Stenosis

    ... up around the ring around the mitral valve (annulus), which can occasionally cause mitral valve stenosis. Other ... the condition of your lungs. Transesophageal echocardiogram. A small transducer attached to the end of a tube ...

  13. Heart valve surgery

    ... Tricuspid valve stenosis Risks The risks of having cardiac surgery include: Death Heart attack Heart failure Bleeding requiring ... and the A.D.A.M. Editorial team. Heart Surgery Read more Heart Valve Diseases Read more Latest ...

  14. Isolated Pulmonary Valve Endocarditis

    Mohammad Ali Hatamizadeh


    Full Text Available Infective endocarditis is one of the most severe complications of parenteral drug abuse. The outstanding clinical feature of infective endocarditis in intravenous drug abusers is the high incidence of right-sided valve infection, and the tricuspid valve is involved in 60% to 70% of the cases. We herein report a case of isolated pulmonic valve infective endocarditis with a native pulmonary valve.

  15. Aerodynamic Shutoff Valve

    Horstman, Raymond H.


    Aerodynamic flow achieved by adding fixed fairings to butterfly valve. When valve fully open, fairings align with butterfly and reduce wake. Butterfly free to turn, so valve can be closed, while fairings remain fixed. Design reduces turbulence in flow of air in internal suction system. Valve aids in development of improved porous-surface boundary-layer control system to reduce aerodynamic drag. Applications primarily aerospace. System adapted to boundary-layer control on high-speed land vehicles.

  16. Heart Valve Diseases

    Your heart has four valves. Normally, these valves open to let blood flow through or out of your heart, and then shut to keep it from flowing ... close tightly. It's one of the most common heart valve conditions. Sometimes it causes regurgitation. Stenosis - when ...

  17. Quadricuspid Aortic Valve

    Mehmet Taşar


    Full Text Available Quadricuspid aortic valve is an extremely rare congenital defect. Isolated form appears frequently. It is seen with aortic valve regurgitation in adulthood. This case report presents a rare clinical finding of an isolated quadricuspid aortic valve with aortic regurgitation in an 64-year-old female who was referred for cardiac evaluation due to newly identified murmur.

  18. Rotating pulse valve for downhole fluid telemetry systems

    Duckworth, A.


    An apparatus for generating pressure pulses in a drilling fluid in a drill collar section of a drill string is described comprising: rotating valve means substantially diametrically mounted in a drill string segment, said rotating valve means alternating between a first position corresponding to more resistance to the flow of drilling fluid and a second position corresponding to less resistance to the flow of drilling fluid, said rotating valve means being impelled by the flow of drilling fluid; and restraining means disposed in the drill collar segment, said restraining means restraining said rotating valve means in said first position and releasing said rotating valve means from said first position in response to control signals indicative of a downhole condition.

  19. Pulmonary-Valve Replacement in Adults: Results With the Medtronic Freestyle Valve.

    Ramanan, Sowmya; Doll, Nicolas; Boethig, Dietmar; Tafer, Nadir; Horke, Alexander; Roques, Xavier; Hemmer, Wolfgang Bruno; Roubertie, François


    We used the Medtronic Freestyle valve (Medtronic, Minneapolis, MN) as an orthotopic conduit in pulmonary valve replacement in repaired tetralogy of Fallot and as part of the Ross procedure. Midterm outcomes and hemodynamic status of this conduit were analyzed and performances in both subgroups were compared. From February 2002 to July 2012, 115 Freestyle valves were implanted in 52 patients with tetralogy of Fallot and 63 patients within the Ross procedure. Preoperative and perioperative data were reviewed retrospectively in this bicentric study. Mean age at valve surgery was 37 ± 13 years. Median implanted valve size was 27 mm (21 to 29). Early postoperative mortality was 3.48%. There was 100% follow-up for the survivors at a mean of 4.38 ± 2.52 years. There was 1 case of thromboembolism (0.89%), 6 endocarditis (5.4%), and 9 (7.8%) conduit re-interventions. Echocardiography at discharge and last follow-up showed average peak systolic transvalvular gradients of 12.4 ± 5.1 and 18.7 ± 8.8 mm Hg, respectively. Ten patients had significant proximal anastomotic gradients of greater than 50 mm Hg and 4 moderate conduit regurgitations. Survival was 96.52%. No valve degeneration was seen in 87.82% at 5 years. The only risk factor identified for valve re-intervention was conduit implantation without infundibular hood (p = 0.01 in multivariate analysis). Mid-term data show that Freestyle valves are well suited for pulmonary valve replacement in adults in both categories. The surgical technique used in valve implantation is important to ensure conduit durability. These results and accessibility to the Freestyle valve make this an acceptable alternative to homografts. Copyright © 2015 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.

  20. Advantages with small control valves

    Nilsson, Gunnar


    Between 1995 and 2005, the Swedish District Heating Association carried out several research projects concerning small dimensions on control valves. This lecture aims at giving a summary of these findings which, if they are carried out, have a great impact on the district heating system. The outcome is advantages on both the production side and the customer side. Some of the project's conclusions are as follows: 1. The simulations show that the consequences of temperature disturbances can be reduced when applying smaller control valves, especially at low outdoor temperatures (-5 deg C). 2. The consequences of flow disturbances (pump stop) are not depending on the outdoor temperature (heat demand), but results over the whole year in reduced maximum flow during the process of operation recovery. With adequately reduced valve size, the resulting maximum flow at restart can be approximately reduced to the half, leading in reduced need of pumping peak power. 3. Similarly, the maximum peak power taken from the net at net recovery will be reduced, however, this effect is not as strong as that for flow. 4. Generally, we have found clear indications for that the adjustment of the K{sub vs}-values of control valves in substations should follow a certain logical order of priority. An important factor is the location of substations in respect to the production plant and to the pressure control points in the network. Another important factor is the absolute K{sub vs}-value of the over sizing, i.e. the difference of the actual installed valve and the targeted valve size. 5. Smaller size of control valves means also an improvement of the everyday operation of the district heating net, especially in the case when flow and power peaks are expected to occur. Examples for that could be the morning peaks with increase heat and hot water demands, or such events when the air temperature is decreasing very fast because of weather phenomena. Smaller control valves will smear out the

  1. Main Oxidizer Valve Design

    Addona, Brad; Eddleman, David


    A developmental Main Oxidizer Valve (MOV) was designed by NASA-MSFC using additive manufacturing processes. The MOV is a pneumatically actuated poppet valve to control the flow of liquid oxygen to an engine's injector. A compression spring is used to return the valve to the closed state when pneumatic pressure is removed from the valve. The valve internal parts are cylindrical in shape, which lends itself to traditional lathe and milling operations. However, the valve body represents a complicated shape and contains the majority of the mass of the valve. Additive manufacturing techniques were used to produce a part that optimized mass and allowed for design features not practical with traditional machining processes.

  2. Echocardiographic variables associated with mitral regurgitation after aortic valve replacement for aortic valve stenosis

    Shaimaa A. Mostafa


    Conclusion: Preoperative predictors of residual postoperative MR were large LA and AF while the postoperative variables were high peak and mean pressure gradient across the aortic valve and high LVMI.

  3. A Clinicopathological Study on Aortic Valves in Children

    HUANG Ping; WANG Hongwei; ZHANG Zhenlu; HU Xiufen; LI Yanping; CHENG Peixuan; LIU Jianying


    In order to investigate the clinicopathological characteristics of aortic valve disease in children, all the native surgically excised aortic valves obtained between January 2003 and December 2005 were studied macroscopically and microscopically. The patients' medical records were reviewed and the clinical information was extracted. According to preoperative echocardiography, intraoperative assessment, and postoperative pathology, combined with clinical symptoms and signs, aortic valve diseases were divided into three categories: aortic stenosis (AS), aortic insufficiency (AI), and aortic stenosis with insufficiency (AS-AI). The etiology was determined according to the macroscopic, microscopic and clinical findings. The results showed that among 70 aortic valves, patient age ranged from 6 to 18 years, with a mean of 15.4 years, and there were 56 boys and 14 girts (male: female=4:1). Forty-four children only had pure aortic valve disease, and the other 26 children had aortic valve disease associated with other heart valve diseases. There were 5 cases of AS (7.14%), 60 cases of AI (85.71%) and 5 cases of AS-AI (7.14%). The causes were congenital aortic valve malformation (32 cases, 45.71%), rheumatic disease (28 cases, 40%), infective endocarditis (7 cases,10%), Marfan syndrome (2 cases, 2.86%), and undetermined (1 case, 1.43%). It was concluded that the common causes of aortic valve disease in order of frequency in children were congenital aortic valve malformation, rheumatic disease, infective endocarditis, and Marfan syndrome. AI was more common in children with aortic valve disease. Compared with adult patients, congenital bicuspid aortic valve in children was often AI. Histologically, the leaflets of congenital bicuspid aortic valve were mainly myxomatous, fibrosis and calcification less seen. AI was frequently found in rheumatic disease, mostly associated with other heart valve diseases. Macroscopic and microscopic examinations together with clinical

  4. Thermostatic Radiator Valve Evaluation

    Dentz, J. [Advanced Residential Integrated Energy Solutions Collaborative (ARIES), New York, NY (United States); Ansanelli, E. [Advanced Residential Integrated Energy Solutions Collaborative (ARIES), New York, NY (United States)


    A large stock of multifamily buildings in the Northeast and Midwest are heated by steam distribution systems. Losses from these systems are typically high and a significant number of apartments are overheated much of the time. Thermostatically controlled radiator valves (TRVs) are one potential strategy to combat this problem, but have not been widely accepted by the residential retrofit market. In this project, the ARIES team sought to better understand the current usage of TRVs by key market players in steam and hot water heating and to conduct limited experiments on the effectiveness of new and old TRVs as a means of controlling space temperatures and reducing heating fuel consumption. The project included a survey of industry professionals, a field experiment comparing old and new TRVs, and cost-benefit modeling analysis using BEopt™ (Building Energy Optimization software).

  5. Valve selection in aortic valve endocarditis

    Zubrytska, Yana


    Aortic prosthetic valve endocarditis (PVE) is a potentially life-threatening disease. Mortality and incidence of infective endocarditis have been reduced in the past 30 years. Medical treatment of aortic PVE may be successful in patients who have a prompt response after antibiotic treatment and who do not have prosthetic dysfunction. In advanced stages, antibiotic therapy alone is insufficient to control the disease, and surgical intervention is necessary. Surgical treatment may be lifesaving, but it is still associated with considerable morbidity and mortality. The aim of surgery is to perform a radical excision of all infected and necrotic tissue, reconstruction of the left ventricle outflow tract, and replacement of the aortic valve. There is no unanimous consensus on which is the optimal prosthesis to implant in this context, and several surgical techniques have been suggested. We aim to analyze the efficacy of the surgical treatment and discuss the issue of valve selection in patients with aortic valve endocarditis.

  6. Optimization of Valve Disc Using Orthogonal Array and Kriging Model

    Song, Xueguan; Wang, Lin; Kang, Jungho; Kim, Seung Gyu; Jo, Young Jik; Park, Youngchul


    A butterfly valve is a type of flow control device, typically used to regulate a fluid flowing. Currently, FEA is often used to predict the safety in the design of valve disc. Also, the study about the affection of butterfly valve's disc to the valve flow characteristics by using CFD has been done by many researchers. Along with the development of computer technique, design and analysis of computer experiments has becoming more and more important in engineering design and optimization. Hereinto Kriging model is one popular analysis approach for the purpose of creating a cheap "meta-model" as a surrogate to a computationally expensive simulation model. In this paper, the numerical analysis considered the strength, pressure loss coefficient and weight of valve disc simultaneously is investigated to improve the shape of a traditional butterfly valve disc. Firstly, an initial model of butterfly valve is made to evaluate the performance of the valve disc by using CFD and FEM. Then several experiments with different variables combination of the valve disc are conducted by mean of orthogonal array. Finally, the Kriging model is used to find the optimum variables combination of valve disc based on the result of computer experiments. In addition, the optimum result is verified by FEA and CFD simulation again. The result shows that compared with traditional computer experiments, optimization by using Kriging model can improve the weight of the valve disc very effectively in a short time.

  7. Aortic or Mitral Valve Replacement With the Biocor and Biocor Supra


    Aortic Valve Insufficiency; Aortic Valve Regurgitation; Aortic Valve Stenosis; Aortic Valve Incompetence; Mitral Valve Insufficiency; Mitral Valve Regurgitation; Mitral Valve Stenosis; Mitral Valve Incompetence

  8. JenaValve.

    Treede, Hendrik; Rastan, Ardawan; Ferrari, Markus; Ensminger, Stephan; Figulla, Hans-Reiner; Mohr, Friedrich-Wilhelm


    The JenaValve is a next-generation TAVI device which consists of a well-proven porcine root valve mounted on a low-profile nitinol stent. Feeler guided positioning and clip fixation on the diseased leaflets allow for anatomically correct implantation of the device without rapid pacing. Safety and efficacy of transapical aortic valve implantation using the JenaValve were evaluated in a multicentre prospective study that showed good short and midterm results. The valve was CE-mark released in Europe in September 2011. A post-market registry ensures on-going and prospective data collection in "real-world" patients. The transfemoral JenaValve delivery system will be evaluated in a first-in-man study in the near future.

  9. Cryogenic Cam Butterfly Valve

    McCormack, Kenneth J. (Inventor)


    A cryogenic cam butterfly valve has a body that includes an axially extending fluid conduit formed there through. A disc lug is connected to a back side of a valve disc and has a circular bore that receives and is larger than a cam of a cam shaft. The valve disc is rotatable for a quarter turn within the body about a lug axis that is offset from the shaft axis. Actuating the cam shaft in the closing rotational direction first causes the camming side of the cam of the cam shaft to rotate the disc lug and the valve disc a quarter turn from the open position to the closed position. Further actuating causes the camming side of the cam shaft to translate the valve disc into sealed contact with the valve seat. Opening rotational direction of the cam shaft reverses these motions.

  10. Phytotherapy for pain relief.

    Zareba, Grazyna


    Pain is considered the third most common healthcare problem disabling more individuals than heart disease and cancer together. Although pharmacological pain management offers a significant relief in several pain-related diseases, many patients turn to its supplementation with complementary and alternative medicine. Botanicals used in pain therapy can contribute to restoring the quality of life to a patient and may effect and enhance conventional pain management. Herbal analgesic use in several pain-related diseases such as rheumatologic diseases, back pain, cancer, diabetic peripheral neuropathy and migraine will be discussed. In addition, this review describes botanicals with known analgesic activity for which randomized, placebo-controlled, double-blind trials assessing their efficacy in different pain-related diseases have been published and which have been recently evaluated in many systematic reviews with well-described methodology.

  11. Experimental investigation of the fluid dynamic efficiency of a high performance multi-valve internal combustion engine during the intake phase: Influence of valve-valve interference phenomena

    Algieri Angelo


    Full Text Available The purpose of the present work is the analysis of the fluid dynamic behavior of a high performance internal combustion engine during the intake phase. In particular, a four-valve spark-ignition engine has been characterized at the steady flow rig. Dimensionless discharge coefficients have been used to define the global fluid dynamic efficiency of the intake system, while the Laser Doppler Anemometry (LDA technique has been employed to evaluate the mean flow in the valve curtain area and to characterise the interference phenomena between the two intake valves. The investigation has shown the significant influence of the valve lift on the volumetric efficiency of the intake apparatus. Moreover, the experimental analysis has highlighted that the valve-valve interference phenomena have a relevant impact on the head breathability, on the flow development within the combustion chamber and on the velocity standard deviations.

  12. Fracturing mechanics before valve-in-valve therapy of small aortic bioprosthetic heart valves

    Johansen, Peter; Engholt, Henrik; Tang, Mariann


    AIMS: Patients with degraded bioprosthetic heart valves (BHV) who are not candidates for valve replacement may benefit from transcatheter valve-in-valve (VIV) therapy. However, at smaller sized surgical BHV the resultant orifice may become too narrow. To overcome this, the valve frame can be frac...

  13. Modeling the Mitral Valve

    Kaiser, Alexander


    The mitral valve is one of four valves in the human heart. The valve opens to allow oxygenated blood from the lungs to fill the left ventricle, and closes when the ventricle contracts to prevent backflow. The valve is composed of two fibrous leaflets which hang from a ring. These leaflets are supported like a parachute by a system of strings called chordae tendineae. In this talk, I will describe a new computational model of the mitral valve. To generate geometry, general information comes from classical anatomy texts and the author's dissection of porcine hearts. An MRI image of a human heart is used to locate the tips of the papillary muscles, which anchor the chordae tendineae, in relation to the mitral ring. The initial configurations of the valve leaflets and chordae tendineae are found by solving solving an equilibrium elasticity problem. The valve is then simulated in fluid (blood) using the immersed boundary method over multiple heart cycles in a model valve tester. We aim to identify features and mechanisms that influence or control valve function. Support from National Science Foundation, Graduate Research Fellowship Program, Grant DGE 1342536.

  14. Mitral valve prolapse.

    Gould, L; Gopalaswamy, C


    Mitral valve prolapse is a very common condition. It occurs in 4-5% of the population. It may be idiopathic or associated with a number of other conditions. Myxomatous degeneration is the underlying mechanism of mitral valve prolapse. Most patients with mitral valve prolapse have no symptoms. When symptoms do occur, palpitations, chest pain and dyspnea are the major complaints. The midsystolic click occasionally followed by the late systolic murmur are the typical physical findings. The echocardiogram plays a big role in the diagnosis of mitral valve prolapse. The beta blockers are used in the treatment of the symptomatic patient.

  15. Biological heart valves.

    Ciubotaru, Anatol; Cebotari, Serghei; Tudorache, Igor; Beckmann, Erik; Hilfiker, Andres; Haverich, Axel


    Cardiac valvular pathologies are often caused by rheumatic fever in young adults, atherosclerosis in elderly patients, or by congenital malformation of the heart in children, in effect affecting almost all population ages. Almost 300,000 heart valve operations are performed worldwide annually. Tissue valve prostheses have certain advantages over mechanical valves such as biocompatibility, more physiological hemodynamics, and no need for life-long systemic anticoagulation. However, the major disadvantage of biological valves is related to their durability. Nevertheless, during the last decade, the number of patients undergoing biological, rather than mechanical, valve replacement has increased from half to more than three-quarters for biological implants. Continuous improvement in valve fabrication includes development of new models and shapes, novel methods of tissue treatment, and preservation and implantation techniques. These efforts are focused not only on the improvement of morbidity and mortality of the patients but also on the improvement of their quality of life. Heart valve tissue engineering aims to provide durable, "autologous" valve prostheses. These valves demonstrate adaptive growth, which may avoid the need of repeated operations in growing patients.

  16. Waiver Plan Generates Relief, Fret

    Klein, Alyson; McNeil, Michele


    While the Obama administration's plan to offer states relief from parts of the No Child Left Behind (NCLB) Act--if they agree to embrace unspecified education redesign priorities--has drawn kudos from some quarters, it isn't sitting well in others. Officials in a number of states have praised the idea as an opportunity for badly needed relief from…

  17. A piezoelectrically actuated ball valve

    Erwin, L. R.; Schwartz, H. W.; Teitelbaum, B. R.


    Bimorph strip composed of two layers of poled piezoelectric ceramic material closes and opens valve. Strip performs like capacitator, allowing initial inrush of current when valve is energized and then only small leakage current flows as valve remains energized.

  18. 24 CFR 965.508 - Individual relief.


    ... 24 Housing and Urban Development 4 2010-04-01 2010-04-01 false Individual relief. 965.508 Section... relief. Requests for relief from surcharges for excess consumption of PHA-purchased utilities, or from... appropriate. The PHA's criteria for granting such relief, and procedures for requesting such relief, shall be...

  19. Determination of trace metal ions via on-line separation and preconcentration by means of chelating Sepharose beads in a sequential injection lab-on-valve (SI-LOV) system coupled to electrothermal atomic absorption spectrometric detection

    Long, Xiangbao; Hansen, Elo Harald; Miró, Manuel


    The analytical performance of an on-line sequential injection lab-on-valve (SI-LOV) system using chelating Sepharose beads as sorbent material for the determination of ultra trace levels of Cd(II), Pb(II) and Ni(II) by electrothermal atomic absorption spectrometry (ETAAS) is described and discussed...

  20. Percutaneous aortic valve replacement using a W-model valved stent: a preliminary feasibility study in sheep

    BAI Yuan; ZONG Gang-jun; WANG Yan-yan; JIANG Hai-bin; LI Wei-ping; WU Hong; ZHAO Xian-xian; QIN Yong-wen


    Background Percutaneous aortic valve replacement is a promising strategy in the treatment of patients with aortic valve stenosis. And many kinds of valved stents have been implanted in selected patients worldwide. However, the clinical experience is still limited. We developed a W-model valved stent and evaluated the feasibility and safety of percutaneous implantation of the device in the native aortic valve position.Methods A self expanding nitinol stent with W-model, containing porcine pericardium valves in its proximal part, was implanted in six sheep by means of a 14 French catheter through the right common lilac artery under guidance of fluoroscopy. During stent deployment the original aortic valve was pushed against the aortic wall by the self expanding force of the stent while the new valve was expanded. These sheep were followed up shortly after procedure with supra-aortic angiogram and left ventriculography. Additionally, one sheep was sacrificed after the procedure for anatomic evaluation.Results It was possible to replace the aortic valve in the beating heart in four sheep. The procedure failed in two sheep due to coronary orifice occlusion in one case and severe aortic valve regurgitation in the other case. One sheep was killed one hour after percutaneous aortic valve replacement for anatomic evaluation. There were no signs of damage of the aortic intima, or of obstruction of the coronary orifice.Conclusions Percutaneous aortic valve replacement with a W-model valved stent in the beating heart is possible. Further studies are mandatory to assess safety and efficacy of this kind of valved stent in larger sample size and by longer follow-up period.

  1. Percutaneous pulmonary valve implantation preceded by routine prestenting with a bare metal stent

    Demkow, Marcin; Biernacka, Elzbieta Katarzyna; Spiewak, Mateusz


    Objectives: To evaluate the effectiveness and safety of percutaneous pulmonary valve implantation (PPVI) with routine prestenting with a bare metal stent (BMS). Background: PPVI is a relatively new method of treating patients with repaired congenital heart disease (CHD). Results of PPVI performed...... X-ray to screen for device integrity. Results: PPVI was performed with no serious complications in all patients (n = 10, mean age 26.8 ± 4.0 years, 60% males). In nine patients with significant pulmonary stenosis, peak right ventricular outflow tract (RVOT) gradient was reduced from a mean of 80......% ± 1% (P = 0.0008). Relief of RVOT obstruction and restoration of pulmonary valve competence were associated with significant decrease in right ventricular (RV) end-diastolic and end-systolic volumes (125.5 ± 48.6 to 109.2 ± 42.9 mL/m2; P = 0.002 and 68.4 ± 41.5 vs. 50.9 ± 40.6 mL/m2; P = 0...

  2. 两种小型二冲程汽油机的配气方式及特点%Valve Means and Features of Two Kinds of Small Two-stroke Gasoline Engine



    As Small two-stroke gasoline engine has the advantages of small size and easy to move, easy start (especially in cold winter) , easy maintenance and the price is low, it is used not only in a small hand-held e-quipment, but also used as the starter for large diesel engines of some construction machinery (such as bulldozers, loaders etc. ). However, for some reasons, old-fashioned small two-stroke gasoline engines whose intake is controlled by piston skirt are introduced in domestic published works, teaching materials and papers, more than the more advanced small two -stroke gasoline engine in international that's of mass production in domestic from 80of the last century and the intake is controlled by crankcase. In this article, the valve means and features of these two kinds of two-stroke gasoline engine are presented and compared. The results show that intake controlled by crankcase is the development direction of small two-stroke gasoline engine of China.%小型二冲程汽油机由于体积小、移动方便,再加上其易于起动(尤其在寒冷的冬天)、维护方便且价格较低,不但在小型手持机具中,而且在一些工程机械中(如推土机、装载机等)也大量用作其大型柴油机的起动机.然而,由于一些原因,我国目前出版的著作、教材以及发表的论文中,介绍的基本都是比较老式的活塞裙控制进气的小型二冲程汽油机,很少提及目前国际上较为先进,国内从上世纪80年代已成批生产的曲轴箱控制进气的小型二冲程汽油机.本文将这两种二冲程汽油机的配气方式及特点做了比较详细地介绍和对比.说明,曲轴箱控制进气的二冲程汽油机已是我国小型二冲程汽油机的发展方向.

  3. Midterm evaluation of hemodynamics of the Top Hat supraannular aortic valve

    Aagaard, Jan; Nissen, Henrik; Geha, Alexander S


    The CarboMedics Top Hat supraannular aortic valve provides an orifice-to-annulus ratio of 1:1 in most patients, and enhances patient outcomes. This study compared the midterm echocardiographic parameters of 52 patients undergoing aortic valve replacement with a Top Hat valve with those in other...... measurements were compared in 38 patients with aortic valve stenosis. Hemodynamic data were comparable to those of other studies, but the Top Hat prosthesis implanted was significantly larger (by a mean of 3.29 mm) than the valve size indicated using an intraannular valve sizer in 48 patients. Mean effective...... orifice area improved significantly from 0.73 cm(2) preoperatively to 2.04 cm(2) postoperatively. In patients with preoperative aortic valve stenosis, postoperative mean peak gradient was significantly reduced. The larger orifice-to-annulus ratio of the Top Hat valve improved hemodynamic parameters...

  4. Quick-Relief Medications for Lung Diseases

    ... relief medications are used to treat asthma, other lung disease symptoms or an acute episode (such as an ... about the following quick-relief asthma and other lung disease medications: Anticholinergics Anticholinergics are quick-relief asthma and ...

  5. Mitral valve surgery - open

    ... Saunders; 2012:chap 61. Otto CM, Bonow RO. Valvular heart disease. In: Mann DL, Zipes DP, Libby P, Bonow ... Editorial team. Related MedlinePlus Health Topics Heart Surgery Heart Valve Diseases Mitral Valve Prolapse Browse the Encyclopedia A.D. ...

  6. Blocked Urethral Valves

    ... Blocked Urethral Valves Health Issues Listen Español Text Size Email Print Share Blocked Urethral Valves Page Content Article Body Urine leaves the bladder through a tube called the urethra, which in boys passes through the penis. Rarely, small membranes form across the urethra in ...

  7. Shutoff and throttling valve

    Hays, L. G.


    Leaktight shutoff, precise flow control, and very low pressure drop are incorporated in all-metal valve designed for operation under extreme temperatures. Valve constructed with refractory metal is intended for control of high-temperature liquid cesium, but has applications related to control of high- and low-temperature liquids and gases.

  8. Management of moderate functional tricuspid valve regurgitation at the time of pulmonary valve replacement: is concomitant tricuspid valve repair necessary?

    Kogon, Brian; Patel, Manisha; Leong, Traci; McConnell, Michael; Book, Wendy


    Congenital heart defects with a component of pulmonary stenosis are often palliated in childhood by disrupting the pulmonary valve. Patients often undergo subsequent pulmonary valve replacement (PVR) to protect the heart from the consequences of pulmonary regurgitation. In the presence of associated moderate functional tricuspid valve (TV) regurgitation, it is unclear what factors contribute to persistent TV regurgitation following PVR. In particular, it is unknown whether PVR alone will reduce the right ventricular (RV) size and restore TV function or whether concomitant TV annuloplasty is required as well. Thirty-five patients were analyzed. Each patient underwent initial palliation of congenital pulmonary stenosis or tetralogy of Fallot, underwent subsequent PVR between 2002 and 2008, and had at least moderate TV regurgitation at the time of valve replacement. Serial echocardiograms were analyzed. Pulmonary and TV regurgitation, along with RV dilation and dysfunction, were scored (0, none; 1, mild; 2, moderate; 3, severe). RV volume and area were also calculated. Potential risk factors for persistent postoperative TV regurgitation were evaluated. One month following PVR, there was a significant reduction in pulmonary valve regurgitation (mean, 3 vs. 0.39; P regurgitation (mean, 2.33 vs. 1.3; P regurgitation postoperatively between those patients who underwent PVR alone and those who underwent concomitant tricuspid annuloplasty (mean, 1.29 vs. 1.31; P = 0.81). We conclude that following PVR, improvement in TV regurgitation and RV size occurs primarily in the first postoperative month. TV function improved to a similar degree with or without annuloplasty.

  9. Bioprinting a cardiac valve.

    Jana, Soumen; Lerman, Amir


    Heart valve tissue engineering could be a possible solution for the limitations of mechanical and biological prostheses, which are commonly used for heart valve replacement. In tissue engineering, cells are seeded into a 3-dimensional platform, termed the scaffold, to make the engineered tissue construct. However, mimicking the mechanical and spatial heterogeneity of a heart valve structure in a fabricated scaffold with uniform cell distribution is daunting when approached conventionally. Bioprinting is an emerging technique that can produce biological products containing matrix and cells, together or separately with morphological, structural and mechanical diversity. This advance increases the possibility of fabricating the structure of a heart valve in vitro and using it as a functional tissue construct for implantation. This review describes the use of bioprinting technology in heart valve tissue engineering.

  10. Anticoagulation for Prosthetic Valves

    Tsuyoshi Kaneko


    Full Text Available Implantation of prosthetic valve requires consideration for anticoagulation. The current guideline recommends warfarin on all mechanical valves. Dabigatran is the new generation anticoagulation medication which is taken orally and does not require frequent monitoring. This drug is approved for treatment for atrial fibrillation and venous thromboembolism, but the latest large trial showed that this drug increases adverse events when used for mechanical valve anticoagulation. On-X valve is the new generation mechanical valve which is considered to require less anticoagulation due to its flow dynamics. The latest study showed that lower anticoagulation level lowers the incidence of bleeding, while the risk of thromboembolism and thrombosis remained the same. Anticoagulation poses dilemma in cases such as pregnancy and major bleeding event. During pregnancy, warfarin can be continued throughout pregnancy and switched to heparin derivative during 6–12 weeks and >36 weeks of gestation. Warfarin can be safely started after 1-2 weeks of discontinuation following major bleeding episode.

  11. Human Internal Jugular Valve M-mode Ultrasound Characterization

    Menegatti, Erica; Tessari, Mirko; Gianesini, Sergio; Vannini, Maria Elena; Sisini, Francesco; Zamboni, Paolo


    In humans the mechanism governing the internal jugular vein (IJV) valve opening and closure is still unclear. M-mode is used in echo-cardiology for the heart valves assessment. Sometimes it was performed also in deep peripheral veins and in vena cava assessment, but never in the IJV valve. Aim of the present study is to investigate the IJV valves physiology in healthy volunteers, by means of both B and M-mode ultrasound. Eighty-three (83) healthy volunteers (35 Male, 48 Female, 25.7±6.7 y.o.)...

  12. Reconstructive surgery of the aortic valve

    Mendonça José Teles de


    Full Text Available OBJECTIVE: Lacking an ideal valve substitute and motivated by the good results of mitral valve repair since 1990, we faced with determination aortic valve reconstruction surgery. The objective of this paper is to show our experience with this procedure. METHOD: Between January of 1990 and December of 2001; 136 aortic valve repair surgeries were performed. Seventy-five (55.1% of the patients were female and the ages ranged from 4 to 70 years (mean 23.3 ± 1.2 years. Every patient had rheumatic valve disease and insufficiency was the most prevalent type (108 patients - 79.4%, followed by double aortic lesion in 16 (11.7% patients and stenosis in 12 (8.8%. The surgical techniques used were: subcommissural annuloplasty in 74 (54.4% patients, commissurotomy in 38 (27.9%, cusp extension with pericardium in 17 (12.5%, substitution of one cusp in 2 (1.4%, cusp suspension by annuloplasty in 37 (27.2% and Valsalva sinus remodeling in 27 (19.8%. The surgery exclusively involved the aortic valve in 57 (41.9% patients and was associated in 79 (mitral valve replacement in 12, mitral repair in 65, coronary artery bypass grafting in 1 and pulmonary commissurotomy in 1. RESULTS: Hospital mortality was 2.2% and 22 (16.2% patients underwent a new surgery during the follow-up period (57.7 ± 3.5 months. CONCLUSIONS: Aortic valve repair is a safe surgical procedure that can be used in an increasing number of patients with promising results.

  13. Lymphangiogenesis is increased in heart valve endocarditis.

    Niinimäki, Eetu; Mennander, Ari A; Paavonen, Timo; Kholová, Ivana


    Inflammation-associated lymphangiogenesis (IAL) has been identified as part of several acute and chronic inflammation. Sparse data exist on lymphatics during endocarditis. Fifty-two patients with surgically resected valves were included. Endocarditis was present in 18 aortic and 10 mitral valves. Controls consisted of 15 degenerative aortic and 9 degenerative mitral valves. There were 22 males with endocarditis and 17 males in controls. The mean age was 58 (SD 15) years with endocarditis vs. 62 (SD 13) years for controls. Lymphatics were detected by podoplanin antibody immunohistochemistry and morphometrical analysis was performed. The lymphatic density in endocarditis was 833 (SD 529) vessels/mm(2) (range 0-1707) as compared with 39 (SD 60) vessels/mm(2) (range 0-250) in controls (p=0.000). In endocarditis, the mean lymphatic size was 153 (SD 372) μm(2) ranging from 1 to 2034μm(2), whereas it was 30 (SD 29) μm(2), with maximum 90μm(2) and minimum 2μm(2) in controls (p=0.000). IAL is increased in valves with endocarditis as compared with controls. Lymphatics in heart valves may provide a novel means for treatment strategies against endocarditis. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  14. Degenerative processes in bioprosthetic mitral valves in juvenile pigs

    Pedersen Torben B


    Full Text Available Abstract Background Glutaraldehyde-treated bioprosthetic heart valves are commonly used for replacement of diseased heart valves. However, calcification and wear limit their durability, and the development of new and improved bioprosthetic valve designs is needed and must be evaluated in a reliable animal model. We studied glutaraldehyde-treated valves 6 months after implantation to evaluate bioprosthetic valve complications in the mitral position in juvenile pigs. Materials The study material comprised eight, 5-month old, 60-kg pigs. All pigs received a size 27, glutaraldehyde-treated, stented, Carpentier-Edwards S.A.V. mitral valve prosthesis. After six months, echocardiography was performed, and the valves explanted for gross examination, high resolution X-ray, and histological evaluation. Results Five pigs survived the follow-up period. Preexplant echocardiography revealed a median peak and mean velocity of 1.61 m/s (range: 1.17-2.00 and 1.20 (SD = ±0.25, respectively, and a median peak and mean pressure difference of 10.42 mmHg (range: 5.83-16.55 and 6.51 mmHg (SD = ±2.57, respectively. Gross examination showed minor thrombotic depositions at two commissures in two valves and at all three commissures in three valves. High resolution X-ray imaging revealed different degrees of calcification in all explanted valves, primarily in the commissural and belly areas. In all valves, histological evaluation demonstrated various degrees of fibrous sheath formation, limited immunological infiltration, and no overgrowth of host endothelium. Conclusions Bioprosthetic glutaraldehyde-treated mitral valves can be implanted into the mitral position in pigs and function after 6 months. Echocardiographic data, calcification, and histological examinations were comparable to results obtained in sheep models and human demonstrating the suitability of the porcine model.

  15. Southern Alaska Coastal Relief Model

    National Oceanic and Atmospheric Administration, Department of Commerce — NOAA's National Geophysical Data Center (NGDC) is building coastal-relief models (CRM) for select U.S. coastal regions. Bathymetric, topographic, and shoreline data...

  16. Face-Sealing Butterfly Valve

    Tervo, John N.


    Valve plate made to translate as well as rotate. Valve opened and closed by turning shaft and lever. Interactions among lever, spring, valve plate, and face seal cause plate to undergo combination of translation and rotation so valve plate clears seal during parts of opening and closing motions.

  17. Morphology and function of Bast's valve : additional insight in its functioning using 3D-reconstruction

    Hofman, R.; Segenhout, J. M.; Buytaert, J. A. N.; Dirckx, J. J. J.; Wit, H. P.


    The utriculo-endolymphatic valve was discovered by Bast in 1928. The function of Bast's valve is still unclear. By means of orthogonal-plane fluorescence optical sectioning (OPFOS) microscopy 3D-reconstructions of the valve and its surrounding region are depicted. The shape of the duct at the utricu

  18. Mesofluidic two stage digital valve

    Jansen, John F; Love, Lonnie J; Lind, Randall F; Richardson, Bradley S


    A mesofluidic scale digital valve system includes a first mesofluidic scale valve having a valve body including a bore, wherein the valve body is configured to cooperate with a solenoid disposed substantially adjacent to the valve body to translate a poppet carried within the bore. The mesofluidic scale digital valve system also includes a second mesofluidic scale valve disposed substantially perpendicular to the first mesofluidic scale valve. The mesofluidic scale digital valve system further includes a control element in communication with the solenoid, wherein the control element is configured to maintain the solenoid in an energized state for a fixed period of time to provide a desired flow rate through an orifice of the second mesofluidic valve.

  19. Aortic valve replacement

    Kapetanakis, Emmanouil I; Athanasiou, Thanos; Mestres, Carlos A


    BACKGROUND AND AIMS OF THE STUDY: Prompted by anecdotal evidence and observations by surgeons, an investigation was undertaken into the potential differences in implanted aortic valve prosthesis sizes, during aortic valve replacement (AVR) procedures, between northern and southern European...... countries. METHODS: A multi-institutional, non-randomized, retrospective analysis was conducted among 2,932 patients who underwent AVR surgery at seven tertiary cardiac surgery centers throughout Europe. Demographic and perioperative variables including valve size and type, body surface area (BSA) and early...


    Prashanth Kumar


    Full Text Available Mechanical prosthetic valves are predisposed to bleeding, thrombosis & thromboembolic complications. Overall incidence of thromboembolic complications is 1% per year who are on oral anticoagulants, whereas bleeding complications incidence is 0.5% to 6.6% per year. 1, 2 Minimization of Scylla of thromboembolic & Charybdis of bleeding complication needs a balancing act of optimal antithrombotic therapy. We are reporting a case of middle aged male patient with prosthetic mitral valve presenting in heart failure. Patient had discontinued anticoagulants, as he had subdural hematoma in the past. He presented to our institute with a giant prosthetic valve thrombus.

  1. Danfos: Thermostatic Radiator Valves

    Gregersen, Niels; Oliver, James; Hjorth, Poul G.


    This problem deals with modelling the flow through a typical Danfoss thermostatic radiator valve.Danfoss is able to employ Computational Fluid Dynamics (CFD) in calculations of the capacity of valves, but an experienced engineer can often by rules of thumb "guess" the capacity, with a precision...... similar to the one achieved by the expensive and time-consuming CFD calculations. So CFD is only used in case of entirely new designs or where a very detailed knowledge of the flow is required. Even though rules of thumb are useful for those, who have developed them, Danfoss needs an objective and general...... method that can be used to predict the performance of valves....

  2. A valve disk

    Khayrullin, N.A.; Isayev, B.N.; Kruglov, S.A.; Molokanov, Yu.K.; Shchelkunov, V.A.; Shegay, V.R.; Vizhgorodskiy, B.N.


    A valve disk is proposed which includes a horizontal bed, on which there are laminar valves arranged in staggered order. To ensure the stable and effective operation of the disk in a broad range of loads by compensating for the direct flow and the partial sectioning of the disk bed, it is equipped with compensating elements installed in openings in the bed and hinged with it. They are made in the form of straight, triangular prisms with ports in the bases. The prisms are installed with the capability of movement relative to the disk bed. The valves are positioned on the upper lateral facets of the compensating elements.

  3. 7 CFR 760.106 - Equitable relief.


    ... 7 Agriculture 7 2010-01-01 2010-01-01 false Equitable relief. 760.106 Section 760.106 Agriculture... Assistance Programs § 760.106 Equitable relief. (a) The Secretary may provide equitable relief on a case-by... accordance with the FCIA (7 U.S.C. 1501-1524) or (ii) Application closing date for NAP. (b) Equitable relief...

  4. Patient outcome and valve performance following a second aortic valve homograft replacement.

    Hasnat, K; Birks, E J; Liddicoat, J; Hon, J K; Edwards, S; Glennon, S; Yacoub, M H


    Homograft valves offer many advantages; however, there is concern about their use in second aortic valve replacement because of the complexity of the procedure and the possibility of accelerated degeneration. One hundred and forty-four patients underwent a second aortic homograft replacement between 1973 and 1997 (mean follow-up 6.5+/-5 years, range 1 to 20 years). Eighty-three were male, and 61 were female, aged 17 to 77 years, mean 49.0 years. All patients had undergone previous aortic valve replacement with a homograft. The indication for reoperation was aortic regurgitation in 75 patients (52.1%), aortic stenosis in 28 (19.4%), and mixed aortic valve disease in 41 (28.5%). Root replacement was performed in 54 patients (38%) and subcoronary in 90 (62.5%). Early mortality was 3.4%. The actuarial survival rate was 93% and 82% at 5 and 10 years, respectively. Freedom from tissue degeneration was 96% and 80% at 5 and 10 years, respectively, and freedom from reoperation was 97% and 82% at 5 and 10 years, respectively. This study shows that a second aortic valve homograft replacement results in good early and long-term survival. Accelerated degeneration does not occur. Left ventricular performance is improved, and earlier surgery could further improve outcome, indicating that an aortic homograft is a safe, durable option for patients requiring a second aortic valve replacement.

  5. Surgical double valve replacement after transcatheter aortic valve implantation and interventional mitral valve repair.

    Wendeborn, Jens; Donndorf, Peter; Westphal, Bernd; Steinhoff, Gustav


    Transcatheter aortic valve implantation, as well as interventional mitral valve repair, offer reasonable therapeutic options for high-risk surgical patients. We report a rare case of early post-interventional aortic valve prosthesis migration to the left ventricular outflow tract, with paravalvular leakage and causing severe mitral valve regurgitation. Initial successful interventional mitral valve repair using a clipped edge-to-edge technique revealed, in a subsequent procedure, the recurrence of mitral valve regurgitation leading to progressive heart failure and necessitating subsequent surgical aortic and mitral valve replacement.

  6. Mitral Valve Disease

    ... for more information on procedures, news, and pre- & post-operative care. Section Navigation Select Topic Aortic Valve Disease ... is most commonly caused by inflammation from rheumatic fever, a disease that is related to strep infections; ...

  7. Valve Repair or Replacement

    ... valve surgery can be done using a robot. Robotic surgery does not require a large incision in the ... The Texas Heart Institute has a robot. With robotic surgery, the surgeon has a control console, a side ...

  8. Pulmonary valve stenosis

    ... valvuloplasty - pulmonary Images Heart valves References Carabello BA. Valvular heart disease. In: Goldman L, Schafer AI, eds. Goldman's Cecil ... Saunders; 2016:chap 69. Otto CM, Bownow RO. Valvular heart disease. In: Mann DL, Zipes DP, Libby P, Bonow ...

  9. Mitral valve regurgitation

    ... and dentist if you have a history of heart valve disease or congenital heart disease before treatment. Some people ... the middle Heart, front view References Carabello BA. Valvular heart disease. In: Goldman L, Schafer AI, eds. Goldman's Cecil ...

  10. Mitral Valve Prolapse

    ... Kawasaki Disease Long Q-T Syndrome Marfan Syndrome Metabolic Syndrome Mitral Valve Prolapse Myocardial Bridge Myocarditis Obstructive Sleep Apnea Pericarditis Peripheral Vascular Disease Rheumatic Fever Sick Sinus Syndrome Silent Ischemia Stroke Sudden ...

  11. Electromechanically Actuated Valve for Controlling Flow Rate

    Patterson, Paul


    A proposed valve for controlling the rate of flow of a fluid would include an electric-motor-driven ball-screw mechanism for adjusting the seating element of the valve to any position between fully closed and fully open. The motor would be of a type that can be electronically controlled to rotate to a specified angular position and to rotate at a specified rate, and the ball screw would enable accurate linear positioning of the seating element as a function of angular position of the motor. Hence, the proposed valve would enable fine electronic control of the rate of flow and the rate of change of flow. The uniqueness of this valve lies in a high degree of integration of the actuation mechanism with the flow-control components into a single, relatively compact unit. A notable feature of this integration is that in addition to being a major part of the actuation mechanism, the ball screw would also be a flow-control component: the ball screw would be hollow so as to contain part of the main flow passage, and one end of the ball screw would be the main seating valve element. The relationships among the components of the valve are best understood by reference to the figure, which presents meridional cross sections of the valve in the fully closed and fully open positions. The motor would be supported by a bracket bolted to the valve body. By means of gears or pulleys and a timing belt, motor drive would be transmitted to a sleeve that would rotate on bearings in the valve body. A ball nut inside the sleeve would be made to rotate with the sleeve by use of a key. The ball screw would pass through and engage the ball nut. A key would prevent rotation of the ball screw in the valve body while allowing the ball screw to translate axially when driven by the ball nut. The outer surface of the ball screw would be threaded only in a mid-length region: the end regions of the outer surface of the ball screw would be polished so that they could act as dynamic sealing surfaces

  12. Comparison of complete versus incomplete stent frame expansion after transcatheter aortic valve implantation with Medtronic CoreValve bioprosthesis.

    Jilaihawi, Hasan; Chin, Derek; Spyt, Tomasz; Jeilan, Mohamed; Vasa-Nicotera, Mariuca; Mohamed, Noor; Bence, Johan; Logtens, Elaine; Kovac, Jan


    We sought to determine the significance of incomplete stent frame expansion after transcatheter aortic valve implantation with the Medtronic-CoreValve device. Incomplete coronary stent expansion is a well-described phenomenon. Transcatheter valves are mounted on stents; however, the incidence of incomplete stent expansion after transcatheter aortic valve implantation, its sequelae and predictors are poorly elucidated. The 18Fr CoreValve revalving system was used to treat anatomically and clinically suitable patients with severe calcific aortic stenosis. The postdeployment stent dimensions were measured on fluoroscopic images at multiple levels of the stent frame. Incomplete expansion at each was defined as Medtronic-CoreValve at a single center from January 2007 to December 2008. For the inflow portion, incomplete expansion was seen in 54% of patients and was unrelated to the aortic valve area, peak or mean aortic valve gradients, or measures of aortic regurgitation, although it was paradoxically associated with a lower incidence of prosthesis-patient mismatch. Incomplete expansion of the constrained portion was seen in 62% of the patients and displayed a trend toward a greater incidence of aortic regurgitation grade 2 or greater, although this was rare. Incomplete expansion of the Medtronic CoreValve stent frame is common. For the most part, valvular hemodynamic function was satisfactory, regardless of the degree of expansion of the stent frame that carries it and a strategy of reluctant postdilation in the context of incomplete stent frame expansion was supported. Copyright © 2011 Elsevier Inc. All rights reserved.

  13. Posterior urethral valves: relationship between vesicoureteral reflux and renal function.

    Cozzi, Denis A; Morgante, Debora; Frediani, Simone; Iaconelli, Romina; Ceccanti, Silvia; Mele, Ermelinda; Cozzi, Francesco


    To investigate the relationship between renal function and vesicoureteral reflux before and after valve ablation in patients with posterior urethral valves. In these patients, back pressure may not be the only cause of renal damage. We conducted a retrospective review of 37 patients with valves consecutively treated between 1970 and 2002. Data were available for 31 patients, 19 of whom presented reflux at presentation. Grade of reflux was ascertained by voiding cystourethrography. Overall renal function was measured by serum creatinine, and split renal function was estimated by dimercaptosuccinic acid scan available for all patients but two. Before relief of obstruction, there was no correlation between split renal function and grade of reflux into 25 kidneys of the 17 patients (r = -.13; 95% CI, -.50 to .27; P = .51). High-grade reflux (grade IV-V) affected 6 of the 11 renal units, with split renal function >40% vs 11 of the 14 units with split renal function 40% vs 4 of the 14 units with split renal function <40% (P = .0005). The good renal function of more than half of the renal units with high-grade reflux at presentation, and the persistence of reflux mainly in nonfunctioning or poorly functioning kidneys after valve ablation, support the concept that in some patients with valves, reflux and renal damage are associated anomalies. Copyright © 2011 Elsevier Inc. All rights reserved.

  14. Spectrum of Aortic Valve Abnormalities Associated with Aortic Dilation Across Age Groups in Turner Syndrome

    Olivieri, Laura J.; Baba, Ridhwan Y.; Arai, Andrew E.; Bandettini, W. Patricia; Rosing, Douglas R.; Bakalov, Vladimir; Sachdev, Vandana; Bondy, Carolyn A.


    Background Congenital aortic valve fusion is associated with aortic dilation, aneurysm and rupture in girls and women with Turner syndrome (TS). Our objective was to characterize aortic valve structure in subjects with TS, and determine the prevalence of aortic dilation and valve dysfunction associated with different types of aortic valves. Methods and Results The aortic valve and thoracic aorta were characterized by cardiovascular magnetic resonance imaging in 208 subjects with TS in an IRB-approved natural history study. Echocardiography was used to measure peak velocities across the aortic valve, and the degree of aortic regurgitation. Four distinct valve morphologies were identified: tricuspid aortic valve (TAV) 64%(n=133), partially fused aortic valve (PF) 12%(n=25), bicuspid aortic valve (BAV) 23%(n=47), and unicuspid aortic valve (UAV) 1%(n=3). Age and body surface area (BSA) were similar in the 4 valve morphology groups. There was a significant trend, independent of age, towards larger BSA-indexed ascending aortic diameters (AADi) with increasing valve fusion. AADi were (mean +/− SD) 16.9 +/− 3.3 mm/m2, 18.3 +/− 3.3 mm/m2, and 19.8 +/− 3.9 mm/m2 (p<0.0001) for TAV, PF and BAV+UAV respectively. PF, BAV, and UAV were significantly associated with mild aortic regurgitation and elevated peak velocities across the aortic valve. Conclusions Aortic valve abnormalities in TS occur with a spectrum of severity, and are associated with aortic root dilation across age groups. Partial fusion of the aortic valve, traditionally regarded as an acquired valve problem, had an equal age distribution and was associated with an increased AADi. PMID:24084490

  15. Transcatheter aortic valve implantation in patients with severe aortic valve stenosis and large aortic annulus, using the self-expanding 31-mm Medtronic CoreValve prosthesis: first clinical experience.

    Nijhoff, Freek; Agostoni, Pierfrancesco; Amrane, Hafid; Latib, Azeem; Testa, Luca; Oreglia, Jacopo A; De Marco, Federico; Samim, Mariam; Bedogni, Francesco; Maisano, Francesco; Bruschi, Giuseppe; Colombo, Antonio; Van Boven, Ad J; Stella, Pieter R


    With the introduction of the 31-mm Medtronic CoreValve prosthesis, patients with large aortic annulus have become eligible for transcatheter aortic valve implantation. The aim of this study was to evaluate the feasibility, efficacy, and safety of transcatheter aortic valve implantation using the 31-mm Medtronic CoreValve in patients with severe aortic valve stenosis and large aortic annulus. Five institutions in the Netherlands and Italy participated in a retrospective multicenter registry. Clinical, procedural, and imaging data of patients treated with the 31-mm Medtronic CoreValve were retrospectively collected in accordance with the Valve Academic Research Consortium-2 criteria. Between August 2011 and November 2012, 47 patients (44 men, mean age 77.6 ± 8.9 years) received the 31-mm Medtronic CoreValve prosthesis for severe aortic stenosis. Device success (correct positioning of a single valve with intended performance and no all-cause 30-day mortality) was achieved in 31 patients (66.0%). Reasons for failing the device success criteria were significant prosthetic aortic regurgitation in 3 patients (6.4%), second valve implantation in 10 patients (21.2%) (8 cases of malpositioning with high-grade aortic regurgitation, 1 acute valve dislocation, and 1 delayed valve dislocation), 1 of whom died intrahospital, and in-hospital mortality in a further 3 patients (6.4%). Peak and mean transaortic gradients decreased significantly (P Medtronic CoreValve seemed to be challenging, even in experienced hands. If the prosthesis is properly implanted, it offers adequate valve hemodynamics and proper functioning. Copyright © 2014 The American Association for Thoracic Surgery. Published by Mosby, Inc. All rights reserved.

  16. Implantation of the CoreValve percutaneous aortic valve.

    Lamarche, Yoan; Cartier, Raymond; Denault, André Y; Basmadjian, Arsène; Berry, Colin; Laborde, Jean-Claude; Bonan, Raoul


    Surgical aortic valve replacement is the only recommended treatment for significant aortic valve stenosis. Percutaneous aortic valve replacement appears to be a novel option for high-risk patients. We report the implantation of the ReValving system (CoreValve, Paris, France) in a 64-year-old woman who was refused aortic valve replacement surgery for critical aortic stenosis and left ventricular dysfunction because of severe pulmonary fibrosis. After anesthesia, the patient was put on femorofemoral cardiopulmonary bypass, and underwent a balloon valvuloplasty with subsequent retrograde aortic valve replacement by the ReValving system. Transesophageal echocardiographic monitoring of the patient's hemodynamics showed immediate improvements of the valvular area and left ventricular ejection fraction and only traces of paravalvular leaks. The patient was easily weaned from ventilation and resumed activity soon after the surgery. A multidisciplinary approach is presently necessary to offer a reliable and safe procedure.

  17. [Technologies for cardiac valve prostheses].

    Nakano, Kiyoharu


    To show the technological development of cardiac valve prostheses, a historical review of both mechanical and biological valve prostheses and a current overview of modern cardiac valve devices are provided. Scince the 1st implantation of Starr-Edwards ball valve in 1960, both mechanical and biological valve prostheses have advanced. The valve design, the material of the leaflet and the hausing of mechanical prostheses have improved. Currently, the majority of the mechanical prostheses are bileaflet tilting disc valves made of pyrolytic carbon, which is antithromboembolic. However, anticoagulation therapy with warfarin is still required. As for the bioprostheses, although the fixation and anti-mineralization methods of the tissues improved, the durability of these valves is still limited. For the material of the current biological valves, the porcine aortic valve or bovine pericardium are used. The tissues are fixed by non-pressure or low-pressure method in glutaraldehyde solution. A stented and non-stented valves are available. Epoch-making events in this field are the implantation of new bioprosthetic valves using tissue engineering methods and the development of the transcatheter valve replacement therapies.

  18. Transcatheter Aortic Valve Replacement for Degenerative Bioprosthetic Surgical Valves

    Dvir, Danny; Webb, John; Brecker, Stephen;


    Transcatheter aortic valve-in-valve implantation is an emerging therapeutic alternative for patients with a failed surgical bioprosthesis and may obviate the need for reoperation. We evaluated the clinical results of this technique using a large, worldwide registry.......Transcatheter aortic valve-in-valve implantation is an emerging therapeutic alternative for patients with a failed surgical bioprosthesis and may obviate the need for reoperation. We evaluated the clinical results of this technique using a large, worldwide registry....

  19. Computerized intraoperative calculation of instantaneous prosthetic aortic valve area.

    DiSesa, V J; Lachman, P; Collins, J J; Cohn, L H


    Improved assessment of valve area is essential to understanding the performance of prosthetic valves. The authors studied six patients undergoing aortic valve replacement using mechanical (ME) or porcine (PO) prostheses. Instantaneous cardiac output (CO) (L/min) was measured in the aorta using an ultrasonic flow probe. Left ventricular and aortic pressures (mmHg) were measured using Millar catheters. Data were analyzed using an IBM PC-AT. Valve area (cm2) was determined using Gorlin's formula (AG) and a new formula for instantaneous area derived mathematically and using a theoretic constant. AG, mean (AI) and peak (Apk) instantaneous areas were compared to geometric measures of area (Aactual) in vitro. Peak instantaneous area correlates best with measured area. Intraoperative assessment using the ultrasonic flow probe and computer analysis is helpful in understanding the dynamic properties of prosthetic valves in vivo.

  20. Reduction of calcification by various treatments in cardiac valves.

    Rao, K P; Shanthi, C


    The importance of glutaraldehyde pretreated bioprosthetic heart valves fabricated from bovine pericardium or porcine aortic valves is well realized in the management of valvular heart diseases. But, calcification limits the durability and is the most frequent cause of failure of these bioprosthetic heart valves. Various research groups in the world are actively involved in describing, understanding, and preventing calcification of bioprosthetic heart valves. Since there is no satisfactory clinical means for preventing or treating this disorder, attempts are made to improve the anticalcification properties of the replacement valves in the preparation stage itself. Research in this area is very active, and many newer approaches are made to mitigate the problem. An attempt has been made in the present article to review various theories put forward to explain the causative factors involved and mechanistic aspects of biocalcification and to present various strategies attempted for the prevention of calcification with the special feature on the work done in the area in our laboratory.


    Wang Qingfeng; Li Yanmin; Zhong Tianyu; Xu Guohua


    Based on the analysis of the-state-of-the-art of pressure compensation of underwater hydraulic systems (UHSs), a new method of pressure compensation of UHSs, whose hydraulic power unit is in the atmospheric circumstance, is proposed. And a pilot-operated relief valve with pressure compensation is realized. The pressure compensation precision is guaranteed by direct detection. Its dynamic performance and stability are improved by a dynamic feedback. Theoretical study, simulation and experiment show that the pilot-operated relief valve with pressure compensation has a fine property of tracking underwater ambient pressure and meet the requirement of underwater ambient pressure compensation.

  2. Control means to improve the gas fire extinguishing system fire valve%改进气体灭火系统防烟防火阀的控制方式



    介绍了深圳地铁三号线气体灭火系统,分析了该系统原防烟防火阀的控制方式,从安全可靠的角度出发,提出了合理的改造方案,并加以实施,达到预期的效果,创造了经济效益。%Introduced the Shenzhen metro line no.3 gas fire-extinguishing systems,analyzes the system of the fire valve control mode of original,from the point of view of safe and reliable,put forward the reasonable reconstruction scheme,and implement,to achieve the expected effect,create the economic benefit.

  3. Mitral Valve Aneurysm: A Rare Complication of Aortic Valve Endocarditis

    A Moaref


    Full Text Available A 20-year-old intravenous drug abuser man, refered to our hospital with dyspnea and orthopnea. Tranesophagealechocardiography revealed severe aortic regurgitation, healed vegetation of aortic valve and an aneurysm of theanterior leaflet of the mitral valve. The patient was discharged after aortic valve replacement and mitral valverepair.

  4. Research on Valve Body Design of Large Bore Sodium Valve


    Large bore sodium valve is one kind of key equipments of China Demonstration Fast Reactor (CDFR). It is installed in the pipeline before and behind SG units as a locking mechanism. Valve body which is used to bear pressure is the core of sodium valve design.

  5. Fraktalnist deformational relief polycrystalline aluminum

    М.В. Карускевич


    Full Text Available  The possibility of the fractal geometry method application for the analisys of surface deformation structures under cyclic loading is presented.It is shown, that deformation relief of the alclad aluminium alloyes meets the criteria of the fractality. For the fractal demention estimation the method of  “box-counting”can be applied.

  6. Stress relief of transition zones

    Woodward, J.; van Rooyen, D.


    This paper considers the problem of intergranular stress corrosion cracking, initiated on the primary side, in the expansion transition region of roller expanded Alloy 600 tubing. In general it is believed that residual stresses, arising from the expansion process, are the cause of the problem. The work reported here concentrated on the identification of an optimal, in-situ stress relief treatment.

  7. Transcatheter Aortic Heart Valve Thrombosis

    Hansson, Nicolaj C; Grove, Erik L; Andersen, Henning R;


    BACKGROUND: There is increasing focus on transcatheter heart valve (THV) thrombosis. However, there are limited data on incidence, clinical implications and predisposing factors of THV thrombosis following transcatheter aortic valve replacement (TAVR). OBJECTIVES: We assessed the incidence...

  8. Safety valve for offshore borehole

    McGill, H.L.; Randermann, E. Jr.; Musik, O.J.


    The invention concerns a new and improved submarine safety valve with a valve element which rotate, which can be used, in emergencies, to separate the wound-up piping which extends into the borehole and to close the production line.

  9. Midterm Results of Aortic Valve Replacement with Cryopreserved Homografts

    Emre Özker


    Full Text Available Objective: The aim of this study was to analyze the midterm clinical results of aortic valve replacement with cryopreserved homografts.Materials and Methods: Aortic valve replacement was performed in 40 patients with cryopreserved homograft. The indications were aortic valve endocarditis in 20 patients (50%, truncus arteriosus in 6 patients (15%, and re-stenosis or regurtitation after aortic valve reconstruction in 14 (35% patients. The valve sizes ranged from 10 to 27mm. A full root replacement technique was used for homograft replacement in all patients.Results: The 30-day postoperative mortality rate was 12.5% (5 patients. There were four late deaths. Only one of them was related to cardiac events. Overall mortality was 22.5%. Thirty-three patients were followed up for 67±26 months. Two patients needed reoperation due to aortic aneurysm caused by endocarditis. The mean transvalvular gradient significantly decreased after valve replacement (p<0.003. The last follow up showed that the 27 (82% patients had a normal left ventricular function.Conclusion: Cryopreserved homografts are safe alternatives to mechanical valves that can be used when there are proper indications. Although it has a high perioperative mortality rate, cryopreserved homograft implantation is an alternative for valve replacement, particularly in younger patients and for complex surgical problems such as endocarditis that must be minimalized.

  10. Nasal valve surgery.

    Apaydin, Fazil


    Nasal obstruction can be due to internal and external valve problems that can be seen before and after rhinoplasty. The main scope of this article is to concentrate on surgical solutions to these problems. To overcome nasal obstruction at the internal valve, spreader grafts, spreader flaps, upper lateral splay graft, butterfly graft, flaring suture, M-plasty, Z-plasty, and suspension sutures have been described. The management of the external valve problems is possible by using lateral crural dissection and repositioning, lateral crural strut grafts, alar battens, lateral crural turn-in flap, alar rim grafts, and various other methods. It is not easy to decide which techniques would work best in every case. After a thorough examination and analysis, the underlying cause of the nasal obstruction can be understood, and one or multiple procedures can be chosen according to each individual problem.

  11. Percutaneous mitral valve repair.

    Gillinov, A Marc; Liddicoat, John R


    Surgical mitral valve repair is the procedure of choice to treat mitral regurgitation of all etiologies. Whereas annuloplasty is the cornerstone of mitral valve repair, a variety of other surgical techniques are utilized to correct dysfunction of the leaflets and subvalvular apparatus; in most cases, surgical repair entails application of multiple repair techniques in each patient. Preclinical studies and early human experience have demonstrated that some of these surgical repair techniques can be performed using percutaneous approaches. Specifically, there has been great progress in the development of novel technology to facilitate percutaneous annuloplasty and percutaneous edge-to-edge repair. The objectives of this report were to (1) discuss the surgical foundations for these percutaneous approaches; (2) review device design and experimental and clinical results of percutaneous valve repair; and (3) address future directions, including the key challenges of patient selection and clinical trial design.

  12. Valve replacement in pediatric patients:a single center experience

    YU Jian-hua; GUO Hong-wei; ZHANG Gong; WU Shu-ming; SONG Guang-min; SUN Wen-yu


    Background Reconstructive surgery is the primary goal in pediatric patients with valve disease.However,in cases with irreparable valve lesions,valve replacement is the only option.This study aimed to retrospectively analyze the clinical experience of heart valve prosthesis replacement in children.Methods Between January 1990 and July 2009,35 pediatric patients (16 boys,19 girls) underwent mechanical valve replacement in Shandong University Qilu Hospital.The ages ranged from 2.5 to 14 years (mean,(8.8±3.8) years) and body weight varied from 11 to 37 kg (mean,(22.1±5.2) kg).Mechanical valve replacement was performed because of congenital heart disease in 23 patients,rheumatic disease in ten patients and infective endocarditis in two patients.St.Jude bileaflet mechanical valves were implanted in all the 35 patients including mitral valve replacement (MVR) in 18,aortic valve replacement (AVR) in 12,tricuspid valve replacement (TVR) in two,AVR and MVR in two and MVR and TVR in one.The size of the prostheses ranged between 19 and 27 mm.All patients received long-term anticoagulation treatment with sodium warfarin,aiming to maintain an international normalized ratio between 1.5 to 2.0.Follow-up was performed in all the patients with a total follow-up of 119.4 patient-years.Results The operative mortality was 8.57% (3/35).One patient,who underwent cardiac debridement and AVR,died 2 hours after being admitted to the intensive care unit because of severe low cardiac output syndrome and ventricular fibrillation.Two patients died of cardiogenic shock and renal failure during initial hospitalization after the operation.One patient who received replacement of a tricuspid valve developed complete heart block requiring temporary pacing and recovered sinus rhythm 4 days later.Thirty-two patients survived and their cardiac function was in New York Heart Association (NYHA) class Ⅰ to class Ⅱ when discharged.Late events included hemorrhage and endocarditis.Two patients required

  13. Building valve amplifiers

    Jones, Morgan


    Building Valve Amplifiers is a unique hands-on guide for anyone working with tube audio equipment--as an electronics hobbyist, audiophile or audio engineer. This 2nd Edition builds on the success of the first with technology and technique revisions throughout and, significantly, a major new self-build project, worked through step-by-step, which puts into practice the principles and techniques introduced throughout the book. Particular attention has been paid to answering questions commonly asked by newcomers to the world of the valve, whether audio enthusiasts tackling their first build or



    It is disclosed a shut-off valve which acts automatically and has a fully mechanical performance with respect to the loosing of the tower-shape part balance under the effect of the special acceleration Which is arisen from the quakes waves or serious vibrations, while such vibrations are mainly...... resulted from collision or effusion. A static tower has been applied for the main core of this part of the valve which loses balance state under the effect of collision and bounces to the neighboring part, which results in release of the catch and blockage of the gas passing channel....

  15. Pulsatile prosthetic valve flows.

    Phillips, W M; Snyder, A; Alchas, P; Rosenberg, G; Pierce, W S


    The laser Doppler system has been established as a useful tool for eliciting the properties of simulated cardiovascular flows, and thus for comparative studies of flow properties of prosthetic valves. Significant differences among valve types and between models of one type have been documented. The complex variations of velocity profiles with time show that comparisons must be made for unsteady pulsatile rather than steady flow, despite the volume and complexity of the data required. Future studies will include methods of compacting the data presentation and improving the details of the experimental stimulation.

  16. Transcatheter Valve-in-Valve: A Cautionary Tale.

    Luc, Jessica G Y; Shanks, Miriam; Tyrrell, Benjamin D; Welsh, Robert C; Butler, Craig R; Meyer, Steven R


    Transcatheter aortic valve replacement (TAVR) by valve-in-valve (VIV) implantation is an alternative treatment for high-risk patients with a degenerating aortic bioprosthesis. We present a case of transapical TAVR VIV with a 29-mm Edwards SAPIEN XT (ESV) (Edwards Lifesciences, Irvine, CA) into a 29-mm Medtronic Freestyle stentless bioprosthesis (Medtronic Inc, Minneapolis, MN) in which unanticipated dilatation of the Freestyle bioprosthesis resulted in intraprocedural embolization of the TAVR valve, necessitating urgent conversion to a conventional surgical aortic valve replacement (AVR). Our experience suggests that TAVR VIV with the 29-mm ESV in the setting of a degenerated 29-mm Freestyle stentless bioprosthesis must be undertaken with caution.

  17. Minimally invasive "pocket incision" aortic valve surgery.

    Yakub, M A; Pau, K K; Awang, Y


    A minimally invasive approach to aortic valve surgery through a transverse incision ("pocket incision") at the right second intercostal space was examined. Sixteen patients with a mean age of 30 years underwent this approach. The third costal cartilage was either excised (n = 5) or dislocated (n = 11). The right internal mammary artery was preserved. Cardiopulmonary bypass (CPB) was established with aortic-right atrial cannulation in all except the first case. Aortic valve replacements (AVR) were performed in 15 patients and one had aortic valve repair with concomitant ventricular septal defect closure. There was no mortality and no major complications. The aortic cross-clamp, CPB and operative times were 72 +/- 19 mins, 105 +/- 26 mins and 3 hrs 00 min +/- 29 mins respectively. The mean time to extubation was 5.7 +/- 4.0 hrs, ICU stay of 27 +/- 9 hrs and postoperative hospital stay of 5.1 +/- 1.2 days. Minimally invasive "pocket incision" aortic valve surgery is technically feasible and safe. It has the advantages of central cannulation for CPB, preservation of the internal mammary artery and avoiding sternotomy. This approach is cosmetically acceptable and allows rapid patient recovery.

  18. The Team Approach to Pain Relief

    ... Issue Past Issues The Team Approach to Pain Relief Past Issues / Fall 2007 Table of Contents For ... with her quality of life, and acupuncture brought relief from severe shoulder pain. "I'm functional again. ...

  19. A Law and Economics Perspective on Injunctive Relief

    A.I. Ogus (Anthony); L.T. Visscher (Louis)


    textabstractAbstract The Law and Economics perspective on injunctive relief has been developed primarily from the Calabresi and Melamed (1972) distinction between property rules and liability rules, two different judicial means of enforcing legal rights. Their analysis is predicated on the assumpti

  20. Prosthetic valve thrombosis in a patient with mitral valve replacement.

    Bilal, Muhammad; Khan, Muhammad Shahzeb; Haseeb, Abdul; Khan, Abdul Bari


    Prosthetic valve thrombosis within one year after mitral valve replacement is rarely seen in patients on warfarin therapy and without any risk factor. Here, we describe a case of a 39-year- old female, who presented with dyspnoea and shortness of breath 11 months after mitral valve replacement. The echocardiogram revealed severe valvular stenosis due to presence of clots on the mitral valve and restricted motion of the mitral leaflets. As a result of deterioration of general condition and haemodynamic un-stability, plan was made to re-operate for her valve replacement surgery. This case report highlights the diagnosis, prevention and management of patients with prosthetic valve thrombosis following mitral valve replacement.

  1. Unicuspid aortic valve disease: a magnetic resonance imaging study

    Debl, K.; Buchner, S.; Heinicke, N.; Riegger, G.; Luchner, A. [Klinik und Poliklinik fuer Innere Medizin II, Universitaetsklinikum Regensburg (Germany); Djavidani, B.; Poschenrieder, F.; Feuerbach, S. [Inst. fuer Roentgendiagnostik, Universitaetsklinikum Regensburg (Germany); Schmid, C.; Kobuch, R. [Klinik und Poliklinik fuer Herz-, Thorax- und herznahe Gefaesschirurgie, Universitaetsklinikum Regensburg (Germany)


    Purpose: congenitally malformed aortic valves are a common finding in adults with aortic valve disease. Most of these patients have bicuspid aortic valve disease. Unicuspid aortic valve disease (UAV) is rare. The aim of our study was to describe valve morphology and the dimensions of the proximal aorta in a cohort of 12 patients with UAV in comparison to tricuspid aortic valve disease (TAV) using magnetic resonance imaging (MRI). Materials and methods/results: MRI studies were performed on a 1.5 T scanner in a total of 288 consecutive patients with aortic valve disease. 12 aortic valves were retrospectively classified as UAV. Annulus areas and dimensions of the thoracic aorta were retrospectively compared to a cohort of 103 patients with TAV. In UAV, valve morphology was unicuspid unicommissural with a posterior commissure in all patients. Mean annulus areas and mean diameters of the ascending aorta were significantly greater in UAV compared to TAV (12.6 {+-} 4.7 cm{sup 2} vs. 8.7 {+-} 2.3 cm{sup 2}, p < 0.01 and 4.6 {+-} 0.7 cm vs. 3.6 {+-} 0.5 cm, p < 0.0001, respectively), while no differences were observed in the mean diameters of the aortic arch (2.3 {+-} 0.6 cm vs. 2.3 {+-} 0.4 cm, p = 0.69). The diameters of the descending aorta were slightly smaller in UAV compared to TAV (2.2 {+-} 0.5 cm vs. 2.6 {+-} 0.3 cm, p < 0.05). (orig.)

  2. 47 CFR 69.727 - Regulatory relief.


    ... similarly situated customers; and (ii) The price cap LEC excludes all contract tariff offerings from price... customer. (b) Phase II relief. Upon satisfaction of the Phase II triggers specified in §§ 69.709(c) or 69... Pricing Flexibility § 69.727 Regulatory relief. (a) Phase I relief. Upon satisfaction of the Phase I...

  3. 7 CFR 1465.33 - Equitable relief.


    ... 7 Agriculture 10 2010-01-01 2010-01-01 false Equitable relief. 1465.33 Section 1465.33 Agriculture... § 1465.33 Equitable relief. (a) If a participant relied upon the advice or action of any authorized NRCS... participant may be eligible for equitable relief under 7 CFR part 635, section 635.3. The financial or...

  4. 28 CFR 36.504 - Relief.


    ... 28 Judicial Administration 1 2010-07-01 2010-07-01 false Relief. 36.504 Section 36.504 Judicial... COMMERCIAL FACILITIES Enforcement § 36.504 Relief. (a) Authority of court. In a civil action under § 36.503, the court— (1) May grant any equitable relief that such court considers to be appropriate, including...

  5. 29 CFR 553.225 - Early relief.


    ... 29 Labor 3 2010-07-01 2010-07-01 false Early relief. 553.225 Section 553.225 Labor Regulations... relief. It is a common practice among employees engaged in fire protection activities to relieve employees on the previous shift prior to the scheduled starting time. Such early relief time may occur...

  6. 29 CFR 4041.4 - Disaster relief.


    ... 29 Labor 9 2010-07-01 2010-07-01 false Disaster relief. 4041.4 Section 4041.4 Labor Regulations...-EMPLOYER PLANS General Provisions § 4041.4 Disaster relief. When the President of the United States declares that, under the Disaster Relief Act (42 U.S.C. 5121, 5122(2), 5141(b)), a major disaster exists...

  7. 29 CFR 1614.505 - Interim relief.


    ... 29 Labor 4 2010-07-01 2010-07-01 false Interim relief. 1614.505 Section 1614.505 Labor Regulations... OPPORTUNITY Remedies and Enforcement § 1614.505 Interim relief. (a)(1) When the agency appeals and the case... interim relief. (2) Service under the temporary or conditional restoration provisions of paragraph (a)(1...

  8. 7 CFR 276.5 - Injunctive relief.


    ... 7 Agriculture 4 2010-01-01 2010-01-01 false Injunctive relief. 276.5 Section 276.5 Agriculture... Injunctive relief. (a) General. If FNS determines that a State agency has failed to comply with the Food... Secretary may seek injunctive relief against the State agency to require compliance. The Secretary may...

  9. 20 CFR 627.803 - Relief.


    ... 20 Employees' Benefits 3 2010-04-01 2010-04-01 false Relief. 627.803 Section 627.803 Employees' Benefits EMPLOYMENT AND TRAINING ADMINISTRATION, DEPARTMENT OF LABOR GENERAL PROVISIONS GOVERNING PROGRAMS... Relief. In ordering relief, the ALJ shall have the full authority of the Secretary under section 164 of...

  10. 24 CFR 7.44 - Interim relief.


    ... 24 Housing and Urban Development 1 2010-04-01 2010-04-01 false Interim relief. 7.44 Section 7.44... § 7.44 Interim relief. (a) When the Department appeals and the case involves removal, separation, or... outcome of the Department appeal. The employee may decline the offer of interim relief. (b) Service under...

  11. 7 CFR 1466.33 - Equitable relief.


    ... 7 Agriculture 10 2010-01-01 2010-01-01 false Equitable relief. 1466.33 Section 1466.33 Agriculture... Administration § 1466.33 Equitable relief. (a) If a participant relied upon the advice or action of any... relief, to the extent it is deemed desirable by NRCS, to provide a fair and equitable treatment because...

  12. 7 CFR 1470.34 - Equitable relief.


    ... 7 Agriculture 10 2010-01-01 2010-01-01 false Equitable relief. 1470.34 Section 1470.34 Agriculture... § 1470.34 Equitable relief. (a) If a participant relied upon the advice or action of NRCS and did not... be eligible for equitable relief under 7 CFR part 635. The financial or technical liability for any...

  13. 12 CFR 268.505 - Interim relief.


    ... 12 Banks and Banking 3 2010-01-01 2010-01-01 false Interim relief. 268.505 Section 268.505 Banks... REGARDING EQUAL OPPORTUNITY Remedies and Enforcement § 268.505 Interim relief. (a)(1) When the Board appeals... offer of interim relief. (2) Service under the temporary or conditional restoration provisions of...

  14. 7 CFR 636.20 - Equitable relief.


    ... 7 Agriculture 6 2010-01-01 2010-01-01 false Equitable relief. 636.20 Section 636.20 Agriculture... AGRICULTURE LONG TERM CONTRACTING WILDLIFE HABITAT INCENTIVES PROGRAM § 636.20 Equitable relief. (a) If a... as meeting program requirements and grant relief because of the good-faith reliance on the part of...

  15. 7 CFR 795.24 - Relief.


    ... 7 Agriculture 7 2010-01-01 2010-01-01 false Relief. 795.24 Section 795.24 Agriculture Regulations... PROVISIONS COMMON TO MORE THAN ONE PROGRAM PAYMENT LIMITATION General § 795.24 Relief. If a producer relied... reviewing authority makes a more restrictive determination, the Deputy Administrator may grant relief only...

  16. 32 CFR 516.19 - Injunctive relief.


    ... 32 National Defense 3 2010-07-01 2010-07-01 true Injunctive relief. 516.19 Section 516.19 National... RELATIONS LITIGATION Reporting Legal Proceedings to HQDA § 516.19 Injunctive relief. (a) General. Plaintiffs... injunctive relief: (1) Plaintiff's likelihood of success on the merits. (2) Whether plaintiff will be...

  17. 18 CFR 281.215 - Additional relief.


    ... 18 Conservation of Power and Water Resources 1 2010-04-01 2010-04-01 false Additional relief. 281... Additional relief. If an interstate pipeline rejects (under § 281.210 or otherwise) a request for... aggrieved by such action may file a request for relief from curtailment under § 385.206 of this chapter. The...

  18. 49 CFR 1108.4 - Relief.


    ... 49 Transportation 8 2010-10-01 2010-10-01 false Relief. 1108.4 Section 1108.4 Transportation Other... TRANSPORTATION BOARD § 1108.4 Relief. (a) Subject to specification in the complaint, as provided in § 1108.7 herein, an Arbitrator may grant the following types of relief: (1) Monetary damages, to the extent...

  19. Distortion of the CoreValve during transcatheter aortic valve-in-valve implantation due to valve dislocation

    Souteyrand, Geraud, E-mail: [Department of Cardiology, Gabriel Montpied Hospital, CHU Clermont-Ferrand, Clermont-Ferrand (France); ERIM-EA3295, University of Auvergne, Clermont-Ferrand (France); Wilczek, Krzysztof [Department of Cardiology, Medical University of Silesia, Silesian Centre for Herat Diseases, Zabrze (Poland); Innorta, Andrea; Camilleri, Lionel [Department of Cardiology, Gabriel Montpied Hospital, CHU Clermont-Ferrand, Clermont-Ferrand (France); ERIM-EA3295, University of Auvergne, Clermont-Ferrand (France); Chodor, Piotr [Department of Cardiology, Medical University of Silesia, Silesian Centre for Herat Diseases, Zabrze (Poland); Lusson, Jean-René; Motreff, Pascal [Department of Cardiology, Gabriel Montpied Hospital, CHU Clermont-Ferrand, Clermont-Ferrand (France); ERIM-EA3295, University of Auvergne, Clermont-Ferrand (France); Laborde, Jean-Claude [St. George' s Hospital, London (United Kingdom); Chabrot, Pascal; Durel, Nicolas [Department of Cardiology, Gabriel Montpied Hospital, CHU Clermont-Ferrand, Clermont-Ferrand (France); ERIM-EA3295, University of Auvergne, Clermont-Ferrand (France)


    Nowadays transcatheter aortic valve implantation (TAVI) is an accepted alternative to surgical aortic valve replacement for high-risk patients (pts). Successful TAVI procedures for failed aortic surgical bioprosthesis (TAV-in-SAV) have already been reported. In the presented two cases of TAV-in-SAV implantation a strut distortion of the stent was revealed on angiographic imaging and confirmed on control CT scan. In both procedures, a dislocation of the medtronic core valve (MCV) prosthesis during implantation led to valve retrieval, with a necessity of reloading it in the 18F introducer before subsequent implantation of the same valve in correct position.

  20. An electrochemical active valve

    Neagu, C.R.; Gardeniers, J.G.E.; Elwenspoek, M.; Kelly, J.J.


    A novel electrochemical microactuator was developed, which operates as an active valve. The microactuator consists of an electrochemical cell and a membrane that deflects because of the pressure of oxygen gas generated by electrolysis. Relatively large pressures (up to tens of bars) can be reached w

  1. Thermostatic Radiator Valve Evaluation

    Dentz, J.; Ansanelli, E.


    A large stock of multifamily buildings in the Northeast and Midwest are heated by steam distribution systems. Losses from these systems are typically high and a significant number of apartments are overheated much of the time. Thermostatically controlled radiator valves (TRVs) are one potential strategy to combat this problem, but have not been widely accepted by the residential retrofit market.

  2. Heart valve surgery - discharge

    ... ACC guideline for the management of patients with valvular heart disease: executive summary: a report of the American College ... Editorial team. Related MedlinePlus Health Topics Heart Surgery Heart Valve Diseases Browse the Encyclopedia A.D.A.M., Inc. ...

  3. Aortic valve surgery - open

    ... Saunders; 2012:chap 61. Otton CM, Bowow RO. Valvular heart disease. In: Mann DL, Zipes DP, Libby P, Bonow ... Editorial team. Related MedlinePlus Health Topics Heart Surgery Heart Valve Diseases Browse the Encyclopedia A.D.A.M., Inc. ...

  4. Minimising life cycle costs of automated valves in offshore platforms

    Yli-Petays, Juha [Metso Automation do Brasil Ltda., Rio de Janeiro, RJ (Brazil); Niemela, Ismo [Metso Automation, Imatra (Finland)


    Automated process valves play an essential role in offshore platforms operation. If you are able to optimize their operation and maintenance activities you can receive extensive operational savings with minimal investment. Valves used in offshore platforms doesn't differentiate that much from the valves used in downstream but there are certain specialties, which makes the operations more challenging in offshore: Process valves are more difficult to access and maintain because of space limitations. Also spare part inventories and deliveries are challenging because of offshore platform's remote location. To overcome these challenges usage of digital positioners with diagnostic features has become more common because predictive maintenance capabilities enable possibilities to plan the maintenance activities and this way optimise the spare part orders regarding to valves. There are intelligent controllers available for control valves, automated on/off valves as well as ESD-valves and whole network of automated valves on platforms can be controlled by intelligent valve controllers. This creates many new opportunities in regards of optimized process performance or predictive maintenance point-of-view. By means of intelligent valve controllers and predictive diagnostics, condition monitoring and maintenance planning can also be performed remotely from an onshore location. Thus, intelligent valve controllers provide good way to minimize spending related to total cost of ownership of automated process valves. When purchase value of control valve represent 20% of TCO, intelligent positioner and predictive maintenance methods can enable as high as 30% savings over the life cycle of asset so basically it benefit savings higher than whole investment of monitored asset over its life cycle. This is mainly achieved through the optimized maintenance activities since real life examples has shown that with time based maintenance (preventive maintenance) approach 70% of

  5. Long-term outcomes following Medtronic Open Pivot valved conduit.

    Naidoo, Rishendran; Pearse, Bronwyn; Tesar, Peter J; Yap, Su-Ann; Barnett, Adrian G; Fayers, Trevor


    Aortic root replacement is a complex procedure, though subsequent modifications of the original Bentall procedure have made surgery more reproducible. The study aim was to examine the outcomes of a modified Bentall procedure, using the Medtronic Open PivotTM valved conduit. Whilst short-term data on the conduit and long-term data on the valve itself are available, little is known of the long-term results with the valved conduit. Patients undergoing aortic root replacement between February 1999 and February 2010, using the Medtronic Open Pivot valved conduit were identified from the prospectively collected Cardiothoracic Register at The Prince Charles Hospital, Brisbane, Australia. All patients were followed up echocardiographically and clinically. The primary end-point was death, and a Cox proportional model was used to identify factors associated.with survival. Secondary end-points were valve-related morbidity (as defined by STS guidelines) and postoperative morbidity. Predictors of morbidity were identified using logistic regression. A total of 246 patients (mean age 50 years) was included in the study. The overall mortality was 12%, with actuarial 10-year survival 79% and a 10-year estimate of valve-related death of 0.04 (95% CI: 0.004, 0.07). Preoperative myocardial infarction (p = 0.004, HR 4.74), urgency of operation (p = 0.038, HR 2.8) and 10% incremental decreases in ejection fraction (p = 0.046, HR 0.69) were predictive of mortality. Survival was also affected by the valve gradients, with a unit increase in peak gradient reducing mortality (p = 0.021, HR 0.93). Valve-related morbidity occurred in 11 patients. Urgent surgery (p Medtronic Open Pivot valved conduit is a safe and durable option for aortic root replacement, and is associated with low morbidity and 10-year survival of 79%. However, further studies are required to determine the effect of valve gradient on survival.

  6. Service Learning Through Disaster Relief

    Donna J. Duerst


    Full Text Available The Rock County 4-H Disaster Relief Committee raised $1,550 to aid tsunami victims in Sri Lanka and then turned its attention to Hurricane Katrina relief efforts. Thirty-one 4-H youth participated in a service learning trip to the South with the objectives of helping hurricane victims, learning about new cultures and achieving personal growth during three days of service projects in Louisiana and Mississippi. Their written reflections and other evaluative measures revealed they learned about southern culture, gained a greater appreciation for their lives, gained self confidence and developed a desire to help others more often. The trip was a valuable developmental experience for the youth, and information from the trip could be utilized to create similar experiences based on service learning. This article provides an overview of the trip and describes the evaluation methods used to measure learning and assess personal growth.

  7. Measurement of reed valve kinematics

    Fenkl Michael


    Full Text Available The measurement of key kinematic parameters of a reed valve movement is necessary for the further development of the reed valve system. These parameters are dependent on the geometry and material properties of the valve. As they directly affect the quantity of air flowing around the valve, a simple and easy to implement measurement of various valve configuration based on the air flow has been devised and is described in this paper, along with its technical parameters and drawbacks when evaluating reed valves used in reciprocating air compressors. Results are presented for a specimen of a compressor under examination. All kinematic parameters, and timing of the opening and closing of the valve, obtained from the measurement are presented and discussed.

  8. Measurement of reed valve kinematics

    Fenkl, Michael; Dvořák, Václav; Vít, Tomáš


    The measurement of key kinematic parameters of a reed valve movement is necessary for the further development of the reed valve system. These parameters are dependent on the geometry and material properties of the valve. As they directly affect the quantity of air flowing around the valve, a simple and easy to implement measurement of various valve configuration based on the air flow has been devised and is described in this paper, along with its technical parameters and drawbacks when evaluating reed valves used in reciprocating air compressors. Results are presented for a specimen of a compressor under examination. All kinematic parameters, and timing of the opening and closing of the valve, obtained from the measurement are presented and discussed.

  9. Developments in mechanical heart valve prosthesis

    Kalyani Nair; C V Muraleedharan; G S Bhuvaneshwar


    Artificial heart valves are engineered devices used for replacing diseased or damaged natural valves of the heart. Most commonly used for replacement are mechanical heart valves and biological valves. This paper briefly outlines the evolution, designs employed, materials being used,. and important factors that affect the performance of mechanical heart valves. The clinical performance of mechanical heart valves is also addressed. Efforts made in India in the development of mechanical heart valves are also discussed.

  10. Experimental investigation of the check valve behaviour when the flow is reversing

    Himr D.


    Full Text Available Check valve in a pipeline is supposed to prevent the reverse flow and to allow the flow in the positive direction. The construction of check valves follows these requirements, but the check valve must not cause pressure pulsations in transients. It means when the fluid is accelerating or decelerating. The article describes an experimental investigation of a swing check valve when the flow is changing its direction. The check valve was placed in an experimental circuit, where the pressure on the upstream and downstream side of the valve was measured and the current value of flow rate was determined. The goal was to simulate conditions in the real system, where the check valve slam had been observed.

  11. Aortic valve replacement with cryopreserved aortic allograft: ten-year experience.

    Doty, J R; Salazar, J D; Liddicoat, J R; Flores, J H; Doty, D B


    Cryopreserved aortic allograft can be used for aortic valve replacement in congenital, rheumatic, degenerative, and infected native valve conditions, as well as failed prosthetic valves. This study was conducted to determine the long-term results of aortic valve replacement with cryopreserved aortic allografts. Aortic valve replacement with cryopreserved aortic allografts was performed in 117 patients from July 1985 until August 1996. All patients requiring aortic valve replacement regardless of valve disease were considered for allograft replacement; the valve was preferentially used in patients under age 55 years and in the setting of bacterial endocarditis. Four operative techniques involving cryopreserved aortic allografts were used: freehand aortic valve replacement with 120-degree rotation, freehand aortic valve replacement with intact noncoronary sinus, aortic root enlargement with intact noncoronary sinus, and total aortic root replacement. Valve function was assessed by echocardiography during the operation in 78 patients (66%) and after the operation in 77 patients (65%). One-hundred eighteen aortic valve replacements with cryopreserved aortic allografts were performed on 117 patients; mean age was 45.6 years (range 15 to 83 years) and mean follow-up was 4.6 years (range up to 11 years). Intraoperative echocardiography disclosed no significant aortic valve incompetence. There were four operative deaths (3%) and seven late deaths; freedom from valve-related mortality at 10 years was 9:3% +/- 4.55%. New York Heart Association functional status at latest follow-up was normal in 98 (94%) patients. On postoperative echocardiography, 90% had no or trivial aortic valve incompetence. Freedom from thromboembolism at 10 years was 100% and from endocarditis, 98% +/- 2.47%. Seven (6%) patients required valve explantation, four for structural deterioration. At 10 years, freedom from reoperation for allograft-related causes was 92% +/- 3.47%. Aortic valve replacement

  12. Prosthetic valve endocarditis with valvular obstruction after transcatheter aortic valve replacement.

    Pabilona, Christine; Gitler, Bernard; Lederman, Jeffrey A; Miller, Donald; Keltz, Theodore N


    Patients with severe aortic stenosis who are at high risk for open-heart surgery might be candidates for transcatheter aortic valve replacement (TAVR). To our knowledge, this is the first report of Streptococcus viridans endocarditis that caused prosthetic valve obstruction after TAVR. A 77-year-old man who had undergone TAVR 17 months earlier was admitted because of evidence of prosthetic valve endocarditis. A transthoracic echocardiogram revealed a substantial increase in the transvalvular peak gradient and mean gradient in comparison with an echocardiogram of 7 months earlier. A transesophageal echocardiogram showed a 1.5-cm vegetation obstructing the valve. Blood cultures yielded penicillin-sensitive S. viridans. The patient was hemodynamically stable and was initially treated with vancomycin because of his previous penicillin allergy. Subsequent therapy with levofloxacin, oral penicillin (after a negative penicillin skin test), and intravenous penicillin eliminated the symptoms of the infection. Transcatheter aortic valve replacement is a relatively new procedure, and sequelae are still being discovered. We recommend that physicians consider obstructive endocarditis as one of these.

  13. Plastik på trikuspidalklappen (Tricuspid valve annuloplasty. The neglected valve)

    Pedersen, Thais A L; Wierup, Per; Pedersen, Lia Mendes;


    INTRODUCTION: Tricuspid valve regurgitation (TVR) is often secondary to left-sided or congenital heart disease (CHD). Surgical correction of TVR is indicated when the primary abnormalities require operation. MATERIAL AND METHODS: Retrospective analysis of all 50 patients (mean age: 65 years (range......: 24-83), 27 males, 23 females) operated with tricuspid valve annuloplasty (TVA) in our hospital from 2000 to 2007. TVA took place concomitantly with operation for left heart disease (n = 39, 78%) or CHD (n = 11, 22%). RESULTS: Preoperatively, TVR was severe in 40, moderate in six and mild in four....... There were five (10%) early and two (4%) late deaths. Temporary arrhythmias requiring medical treatment occurred in 35 cases, but eight required permanent pacemaker. No tricuspid valve reoperations were performed. CONCLUSIONS: The combination of correction of primary heart abnormalities and TVA is associated...

  14. Transcatheter Versus Surgical Aortic Valve Replacement in Patients With Severe Aortic Valve Stenosis

    Thyregod, Hans Gustav; Steinbrüchel, Daniel Andreas; Ihlemann, Nikolaj


    outcome was the composite rate of death from any cause, stroke, or myocardial infarction (MI) at 1 year. RESULTS: A total of 280 patients were randomized at 3 Nordic centers. Mean age was 79.1 years, and 81.8% were considered low-risk patients. In the intention-to-treat population, no significant...... difference in the primary endpoint was found (13.1% vs. 16.3%; p = 0.43 for superiority). The result did not change in the as-treated population. No difference in the rate of cardiovascular death or prosthesis reintervention was found. Compared with SAVR-treated patients, TAVR-treated patients had more......BACKGROUND: Transcatheter aortic valve replacement (TAVR) is an option in certain high-risk surgical patients with severe aortic valve stenosis. It is unknown whether TAVR can be safely introduced to lower-risk patients. OBJECTIVES: The NOTION (Nordic Aortic Valve Intervention Trial) randomized...

  15. Valve Concepts for Microfluidic Cell Handling

    M. Grabowski


    Full Text Available In this paper we present various pneumatically actuated microfluidic valves to enable user-defined fluid management within a microfluidic chip. To identify a feasible valve design, certain valve concepts are simulated in ANSYS to investigate the pressure dependent opening and closing characteristics of each design. The results are verified in a series of tests. Both the microfluidic layer and the pneumatic layer are realized by means of soft-lithographic techniques. In this way, a network of channels is fabricated in photoresist as a molding master. By casting these masters with PDMS (polydimethylsiloxane we get polymeric replicas containing the channel network. After a plasma-enhanced bonding process, the two layers are irreversibly bonded to each other. The bonding is tight for pressures up to 2 bar. The valves are integrated into a microfluidic cell handling system that is designed to manipulate cells in the presence of a liquid reagent (e.g. PEG – polyethylene glycol, for cell fusion. For this purpose a user-defined fluid management system is developed. The first test series with human cell lines show that the microfluidic chip is suitable for accumulating cells within a reaction chamber, where they can be flushed by a liquid medium.

  16. Ventriculopleural shunting with new technology valves.

    Martínez-Lage, J F; Torres, J; Campillo, H; Sanchez-del-Rincón, I; Bueno, F; Zambudio, G; Poza, M


    Ventriculoperitoneal shunting constitutes the standard procedure for draining cerebrospinal fluid (CSF) in children with hydrocephalus. Ventriculoatrial and ventriculopleural shunting are alternative methods of CSF drainage, which have gained less acceptance. Ventriculopleural shunts are seldom used owing to justified fears of pneumothorax and symptomatic effusions of CSF. The addition of an antisiphon device to standard shunt systems seems to have prevented CSF pleural effusion. From 1988 to 1998, we treated each of six hydrocephalic children with a ventriculopleural shunt. In five cases we used new-technology valves designed to prevent the effects of siphoning with current differential pressure valves. Peritoneal adhesions, recent peritonitis, ascites, and obstruction of a previous ventriculoatrial shunt were the indications for pleural shunting. After a mean follow-up period of 2.5 years all shunts were functioning adequately. Only one patient showed transient symptoms of CSF overdrainage, which were corrected by up-grading the valve setting with the magnet. A late death was unrelated to the pleural shunting procedure. The use of valves of a new design designed to prevent overdrainage seems to account for the satisfactory outcomes observed in this series. We suggest that ventriculopleural shunting should be considered as the preferred alternative to peritoneal drainage in children with intra-abdominal adhesions or with a history of recent peritoneal infection.

  17. Congenital quadricuspid aortic valve: analysis of 11 surgical cases

    TANG Yang-feng; XU Ji-bin; HAN Lin; LU Fang-lin; LANG Xi-long; SONG Zhi-gang; XU Zhi-yun


    Background Congenital quadricuspid aortic valve is rarely seen during aortic valve replacement (AVR).The diagnosis and treatment of the disease were reported in 11 cases.Methods Eleven patients (nine men and two women,mean age 33.4 years) with quadricuspid aortic valve were retrospectively evaluated.Medical records,echocardiograms and surgical treatment were reviewed.Results In accordance with the Hurwitz and Roberts classification,the patients were classified as type A (n=2),type B (n=7),type F (n=1) and type G (n=1).Three patients were associated with other heart diseases,including infective endocarditis and mitral prolaps,left superior vena cava,aortic aneurysm.All had aortic regurgitation (AR) except two with aortic stenosis (AS),detected by color-flow Doppler echocardiography.The congenital quadricuspid aortic valve deformity in seven patients was diagnosed by echocardiography.All patients underwent successful aortic valve replacement.Conclusion Quadricuspid aortic valve is a rare cause of aortic insufficiency,while echocardiography plays an important role in diagnosing the disease.Aortic valve replacement is the major therapy for the disease.

  18. Percutaneous tricuspid valve replacement in childhood

    Mathias Emmel


    Full Text Available Percutaneous replacement of the tricuspid valve with a bovine jugular venous valve (melody valve was successfully undertaken in a 9-year-old boy. The patient had a previous history of bacterial endocarditis of the native tricuspid valve in infancy. Initially, a pericardial patch valve was created, followed by surgical replacement of the valve using a biological tissue valve at 4 years of age. Progressive stenosis and regurgitation of the biological valve, with severe venous congestion and resulting hepatic dysfunction prompted percutaneous valve replacement.

  19. Use of One-Way Intrabronchial Valves in Air Leak Management After Tube Thoracostomy Drainage.

    Gilbert, Christopher R; Casal, Roberto F; Lee, Hans J; Feller-Kopman, David; Frimpong, Bernice; Dincer, H Erhan; Podgaetz, Eitan; Benzaquen, Sadia; Majid, Adnan; Folch, Erik; Gorden, Jed A; Chenna, Praveen; Chen, Alex; Abouzgheib, Wissam; Sanny Nonyane, Bareng Aletta; Yarmus, Lonny B


    A persistent air leak represents significant clinical management problems, potentially affecting morbidity, mortality, and health care costs. In 2008, a unidirectional, intrabronchial valve received humanitarian device exemption for use in managing prolonged air leak after pulmonary resection. Since its introduction, numerous reports exist but no large series describe current utilization or outcomes. Our aim was to report current use of intrabronchial valves for air leaks and review outcome data associated with its utilization. A multicenter, retrospective review of intrabronchial valve utilization from January 2013 to August 2014 was performed at eight centers. Data regarding demographics, valve utilization, and outcomes were analyzed. We identified 112 patients undergoing evaluation for intrabronchial valve placement, with 67% (75 of 112) undergoing valve implantation. Nearly three quarters of patients underwent valve placement for off-label usage (53 of 75). A total of 195 valves were placed in 75 patients (mean 2.6 per patient; range, 1 to 8) with median time to air leak resolution of 16 days (range, 2 to 156). We present the largest, multicenter study of patients undergoing evaluation for intrabronchial valve use for air leak management. Our data suggest the majority of intrabronchial valve placements are occurring for off-label indications. Although the use of intrabronchial valves are a minimally invasive intervention for air leak management, the lack of rigorously designed studies demonstrating efficacy remains concerning. Prospective randomized controlled studies remain warranted. Copyright © 2016 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.

  20. Transcatheter Replacement of Failed Bioprosthetic Valves

    Simonato, Matheus; Webb, John; Kornowski, Ran


    Background-Transcatheter valve implantation inside failed bioprosthetic surgical valves (valve-in-valve [ViV]) may offer an advantage over reoperation. Supra-annular transcatheter valve position may be advantageous in achieving better hemodynamics after ViV. Our objective was to define targets fo...

  1. Performance Characteristics of an Isothermal Freeze Valve

    Hailey, A.E.


    This document discusses performance characteristics of an isothermal freeze valve. A freeze valve has been specified for draining the DWPF melter at the end of its lifetime. Two freeze valve designs have been evaluated on the Small Cylindrical Melter-2 (SCM-2). In order to size the DWPF freeze valve, the basic principles governing freeze valve behavior need to be identified and understood.

  2. "Vanishing" pulmonary valve stenosis

    Nofil I Arain


    Full Text Available Objective: Both spontaneous resolution and progression of mild pulmonary valve stenosis (PS have been reported. We reviewed characteristics of the pulmonary valve (PV to determine factors that could influence resolution of mild PS. Methods: Fifteen asymptomatic pediatric patients with spontaneous resolution of isolated mild PS were retrospectively reviewed. Results: There was no correlation between the PV gradient, clinical presentation, age at diagnosis, or PV morphology. The PV annulus was small at initial presentation, which normalized at follow up. When corrected for the body surface area (z-score, the PV annulus was normal in all patients, including at initial evaluation. Conclusions: Based on our observation, neither age at diagnosis, nor PV-morphology-influenced resolution of mild PS. The variable clinical presentation makes it difficult to categorize and observe mild PS by auscultation alone. The PV annulus z-score could be a useful adjunct to determine the course and serial observation of mild PS.

  3. Transcatheter aortic valve implantation in failed bioprosthetic surgical valves

    Dvir, Danny; Webb, John G; Bleiziffer, Sabine


    IMPORTANCE: Owing to a considerable shift toward bioprosthesis implantation rather than mechanical valves, it is expected that patients will increasingly present with degenerated bioprostheses in the next few years. Transcatheter aortic valve-in-valve implantation is a less invasive approach......, stroke, and New York Heart Association functional class. RESULTS: Modes of bioprosthesis failure were stenosis (n = 181 [39.4%]), regurgitation (n = 139 [30.3%]), and combined (n = 139 [30.3%]). The stenosis group had a higher percentage of small valves (37% vs 20.9% and 26.6% in the regurgitation...

  4. Minimally Invasive Mitral Valve Replacement and Transfemoral Aortic Valve Implantation.

    Rustenbach, Christian; Baumbach, Hardy; Hill, Stephan; Franke, Ulrich F W


    The case is reported of a symptomatic elderly patient with severe mitral regurgitation, severe aortic valve stenosis, and coronary heart disease. The coronary artery disease had been interventionally treated four years previously with stent implantation into the right coronary artery. Published studies have shown that a combination of mitral and aortic valve surgery is associated with a significantly increased risk of mortality and morbidity, particularly in elderly patients. In the present patient, both valvular malformations were successfully treated with a single-step interdisciplinary approach, namely an initial surgical mitral valve replacement followed by transfemoral transcatheter aortic valve replacement.

  5. Anterior Urethral Valves

    Vidyadhar P. Mali


    Full Text Available We studied the clinical presentation and management of four patients with anterior urethral valves; a rare cause of urethral obstruction in male children. One patient presented antenatally with oligohydramnios, bilateral hydronephrosis and bladder thickening suggestive of an infravesical obstruction. Two other patients presented postnatally at 1 and 2 years of age, respectively, with poor stream of urine since birth. The fourth patient presented at 9 years with frequency and dysuria. Diagnosis was established on either micturating cystourethrogram (MCU (in 2 or on cystoscopy (in 2. All patients had cystoscopic ablation of the valves. One patient developed a postablation stricture that was resected with an end-to-end urethroplasty. He had an associated bilateral vesicoureteric junction (VUJ obstruction for which a bilateral ureteric reimplantation was done at the same time. On long-term follow-up, all patients demonstrated a good stream of urine. The renal function is normal. Patients are continent and free of urinary infections. Anterior urethral valves are rare obstructive lesions in male children. The degree of obstruction is variable, and so they may present with mild micturition difficulty or severe obstruction with hydroureteronephrosis and renal impairment. Hence, it is important to evaluate the anterior urethra in any male child with suspected infravesical obstruction. The diagnosis is established by MCU or cystoscopy and the treatment is always surgical, either a transurethral ablation or an open resection. The long-term prognosis is good.

  6. Posterior Urethral Valves

    Steve J. Hodges


    Full Text Available The most common cause of lower urinary tract obstruction in male infants is posterior urethral valves. Although the incidence has remained stable, the neonatal mortality for this disorder has improved due to early diagnosis and intensive neonatal care, thanks in part to the widespread use of prenatal ultrasound evaluations. In fact, the most common reason for the diagnosis of posterior urethral valves presently is the evaluation of infants for prenatal hydronephrosis. Since these children are often diagnosed early, the urethral obstruction can be alleviated rapidly through catheter insertion and eventual surgery, and their metabolic derangements can be normalized without delay, avoiding preventable infant mortality. Of the children that survive, however, early diagnosis has not had much effect on their long-term prognosis, as 30% still develop renal insufficiency before adolescence. A better understanding of the exact cause of the congenital obstruction of the male posterior urethra, prevention of postnatal bladder and renal injury, and the development of safe methods to treat urethral obstruction prenatally (and thereby avoiding the bladder and renal damage due to obstructive uropathy are the goals for the care of children with posterior urethral valves[1].

  7. Supramolecular spin valves

    Urdampilleta, M.; Klyatskaya, S.; Cleuziou, J.-P.; Ruben, M.; Wernsdorfer, W.


    Magnetic molecules are potential building blocks for the design of spintronic devices. Moreover, molecular materials enable the combination of bottom-up processing techniques, for example with conventional top-down nanofabrication. The development of solid-state spintronic devices based on the giant magnetoresistance, tunnel magnetoresistance and spin-valve effects has revolutionized magnetic memory applications. Recently, a significant improvement of the spin-relaxation time has been observed in organic semiconductor tunnel junctions, single non-magnetic molecules coupled to magnetic electrodes have shown giant magnetoresistance and hybrid devices exploiting the quantum tunnelling properties of single-molecule magnets have been proposed. Herein, we present an original spin-valve device in which a non-magnetic molecular quantum dot, made of a single-walled carbon nanotube contacted with non-magnetic electrodes, is laterally coupled through supramolecular interactions to TbPc2 single-molecule magnets (Pc=phthalocyanine). Their localized magnetic moments lead to a magnetic field dependence of the electrical transport through the single-walled carbon nanotube, resulting in magnetoresistance ratios up to 300% at temperatures less than 1 K. We thus demonstrate the functionality of a supramolecular spin valve without magnetic leads. Our results open up prospects of new spintronic devices with quantum properties.

  8. Live three-dimensional transesophageal echocardiography in mitral valve surgery

    MA Ning; LI Zhi-an; MENG Xu; YANG Ya


    Background Live three-dimensional transesophageal echocardiography (live-3D-TEE) is a new technique, but its clinical value is unclear at present. This study aimed to investigate the feasibility, imaging quality and accuracy of live-3D-TEE for assessing mitral valve morphology to determine if live-3D-TEE has important value in mitral valve surgery.Methods Twenty-four patients with mitral valve disease (mean age (47.1 rdiography (2D-TEE) before and after mitral valve surgery. Sensitivity, specificity, and total consistency rates of live-3D-TEE for diagnosing ruptured chordae were calculated and compared to surgeon's findings. We also compared the diagnostic accuracy of mitral valve disease between live-3D-TEE and 2D-TEE.Results Live-3D-TEE allowed visualization of the anatomic structure of the heart online and clearly identified the valvular apparatus and their defects. Sensitivity and specificity for the detection of ruptured chordae by live-3D-TEE were 87.5% and 100% respectively, and the total consistency rate was 95.8%. Additional defects not diagnosted by 2D-TEE were found in three cases (12.5%) preoperatively by live-3D-TEE. Live-3D-TEE could evaluate the function of prosthetic or native valves immediately after operation. One case was re-repaired (4.2%) using guidance by live-3D-TEE. Conclusion Live-3D-TEE enabled evaluation of mitral valve function and provided adequate valuable information before and after mitral valve surgery. We conclude that live-3D-TEE can play an important role in mitral valve surgery.

  9. Aortic valve reconstruction with use of pericardial leaflets in adults with bicuspid aortic valve disease: early and midterm outcomes.

    Song, Meong Gun; Yang, Hyun Suk; Choi, Jong Bum; Shin, Je Kyoun; Chee, Hyun Keun; Kim, Jun Seok


    In this study, we retrospectively analyzed the outcomes of adults with bicuspid aortic valve (BAV) disease who underwent aortic valve reconstructive surgery (AVRS), consisting of replacement of the diseased BAV with 2 or 3 pericardial leaflets plus fixation of the sinotubular junction for accurate and constant leaflet coaptation. From December 2007 through April 2013, 135 consecutive patients (mean age, 49.2 ± 13.1 yr; 73.3% men) with symptomatic BAV disease underwent AVRS. Raphe was observed in 84 patients (62.2%), and the remaining 51 patients had pure BAV without raphe. A total of 122 patients (90.4%) underwent 3-leaflet reconstruction, and 13 (9.6%) underwent 2-leaflet reconstruction. Concomitant aortic wrapping with an artificial graft was performed in 63 patients (46.7%). There were no in-hospital deaths and 2 late deaths (1.5%); 6 patients (4.4%) needed valve-related reoperation. The 5-year cumulative survival rate was 98% ± 1.5%, and freedom from valve-related reoperation at 5 years was 92.7% ± 3.6%. In the last available echocardiograms, aortic regurgitation was absent or trivial in 116 patients (85.9%), mild in 16 (11.9%), moderate in 2 (1.5%), and severe in one (0.7%). The mean aortic valve gradient was 10.2 ± 4.5 mmHg, and the mean aortic valve orifice area index was 1.3 ± 0.3 cm(2)/m(2). The 3-leaflet technique resulted in lower valve gradients and greater valve areas than did the 2-leaflet technique. Thus, in patients with BAV, AVRS yielded satisfactory early and midterm results with low mortality rates and low reoperation risk after the initial procedure.

  10. Latest design of gate valves

    Kurzhofer, U.; Stolte, J.; Weyand, M.


    Babcock Sempell, one of the most important valve manufacturers in Europe, has delivered valves for the nuclear power industry since the beginning of the peaceful application of nuclear power in the 1960s. The latest innovation by Babcock Sempell is a gate valve that meets all recent technical requirements of the nuclear power technology. At the moment in the United States, Germany, Sweden, and many other countries, motor-operated gate and globe valves are judged very critically. Besides the absolute control of the so-called {open_quotes}trip failure,{close_quotes} the integrity of all valve parts submitted to operational forces must be maintained. In case of failure of the limit and torque switches, all valve designs have been tested with respect to the quality of guidance of the gate. The guidances (i.e., guides) shall avoid a tilting of the gate during the closing procedure. The gate valve newly designed by Babcock Sempell fulfills all these characteristic criteria. In addition, the valve has cobalt-free seat hardfacing, the suitability of which has been proven by friction tests as well as full-scale blowdown tests at the GAP of Siemens in Karlstein, West Germany. Babcock Sempell was to deliver more than 30 gate valves of this type for 5 Swedish nuclear power stations by autumn 1995. In the presentation, the author will report on the testing performed, qualifications, and sizing criteria which led to the new technical design.

  11. Mitral Valve Prolapse in Pregnancy

    Shi-Min Yuan

    Full Text Available Abstract Mitral valve prolapse is a benign condition. Mitral regurgitation is only complicated in patients with severe mitral valve prolapse. Women with mitral valve prolapse in the absence of other cardiovascular disorders tolerate pregnancy well and do not develop remarkable cardiac complications. Nevertheless, serious complications of mitral valve prolapse, including arrhythmia, infective endocarditis and cerebral ischemic events, can be present in pregnancy. Debates remain with regard to the use of prophylactic antibiotics and β-blockers in the pregnant women with mitral valve prolapse. The prognosis of the pregnant patients might be closely related to the pathological and (or functional changes of the mitral valve. Non-myxomatous mitral valve prolapse poses no or little obstetric risks in terms of pregnancy, labor and neonatal complications; whereas myxomatous mitral valve prolapse is a major etiology of valvular heart disease in women of childbearing age. In the pregnant patients with mitral valve prolapse progressing into major complications, surgical interventions are considered. Medicinal treatment of such patients with β-blockers should be a concern for the fetal safety.

  12. Innovative Stemless Valve Eliminates Emissions


    Big Horn Valve Inc. (BHVI), of Sheridan, Wyoming, won a series of SBIR and Small Business Technology Transfer (STTR) contracts with Kennedy Space Center and Marshall Space Flight Center to explore and develop a revolutionary valve technology. BHVI developed a low-mass, high-efficiency, leak-proof cryogenic valve using composites and exotic metals, and had no stem-actuator, few moving parts, with an overall cylindrical shape. The valve has been installed at a methane coal gas field, and future applications are expected to include in-flight refueling of military aircraft, high-volume gas delivery systems, petroleum refining, and in the nuclear industry.

  13. Cobalt reduction of NSSS valve hardfacings for ALARA

    Kim, Joo Hak; Lee, Sang Sub [Korea Atomic Energy Research Institute, Taejon (Korea, Republic of)


    This report informs NSSS designer that replacement of materials is one of the major means of ALARA implementation, and describes that NSSS valves with high-cobalt hardfacing are significant contributors to post-shutdown radiation fields caused by activation of cobalt-59 to cobalt-60. Generic procedures for implementing cobalt reduction programs for valves are presented. Discussions are presented of the general and specific design requirements for valve hardfacing in nuclear service. The nuclear safety issues involved with changing valve hardfacing materials are discussed. The common methods used to deposit hardfacing materials are described together with an explanation of the wear measurements. Wear resistance, corrosion resistance, friction coefficient, and mechanical properties of candidate hardfacing alloys are given. World-wide nuclear utility experience with cobalt-free hardfacing alloys is described. The use of low-cobalt or cobalt-free alloys in other nuclear plant components is described. 17 figs., 38 tabs., 18 refs. (Author).

  14. Low radiation dose non-contrast cardiac CT: is it of value in the evaluation of mechanical aortic valve

    Bazeed, Mohamed Fayez (Dept. of Diagnostic Radiology, Faculty of Medicine, Mansoura Univ. (Egypt)), email:; Moselhy, Mohamed Saleh (Cardiology Dept. Faculty of Medicine, Suez Canal Univ. (Egypt)); Rezk, Ahmad Ibrahim (Dept. of Cardiac Surgery, Faculty of Medicine, Aim Shams Univ. (Egypt)); Al-Murayeh, Mushabab Ayedh (Dept. of Cardiac Services, Armed Forces Hospitals Southern Region (Saudi Arabia))


    Background: Prosthetic bileaflet mechanical valve function has been traditionally evaluated using echocardiography and fluoroscopy. Multidetector computed tomography (MDCT) is a novel technique for cardiac evaluation. Purpose: To evaluate bileaflet mechanical aortic valves using a low-milliampere (mA), non-contrast MDCT protocol with a limited scan range. Material and Methods: Forty patients with a bileaflet mechanical aortic valve were evaluated using a non-contrast, low-mA, ECG-gated 64 MDCT protocol with a limited scan range. MDCT findings of opening and closing valve angles were correlated to fluoroscopy and echocardiography. Also, the valve visibility was evaluated on MDCT and fluoroscopy according to a 3-point grading scale. Results: The visualization score with the MDCT was significantly superior to the fluoroscopy (3 vs. 2.7). A strong correlation was noted between the opening (r = 0.82) and closing (r = 0.96) valve angles with MDCT and fluoroscopy without a statistically significant difference (P = 0.31 and 0.16, respectively). The mean effective radiation dose of the suggested protocol was 4 +- 0.5 mSv. Five valves were evaluated using transesophageal echocardiography because the valves were difficult to evaluate with transthoracic echocardiography, and all of these valves were evaluated optimally with MDCT. A high-pressure gradient was noted in nine valves, and the MDCT showed that seven of these valves inadequately opened, and two valves opened well, which resulted in patient valve mismatch. Incomplete valve closure was noted in five valves, and the echocardiography showed significant transvalvular regurgitation in all five valves. Conclusion: MDCT can provide a precise measurement of valve function and can potentially evaluate high-pressure gradients and transvalvular regurgitation

  15. Whitey Gauge and Root Valves (VPS)

    MISKA, C.


    These valves are 1/2 inch ball valves fabricated of 316 stainless steel: Packing is TFE (standard). They are used as isolation valves for pressure instrumentation in the Vacuum Pumping and Helium System.

  16. Star GK Bileaflet Mechanical Valve Prosthesis-Patient Mismatch After Mitral Valve Replacement: A Chinese Multicenter Clinical Study

    Cao, Hua; Qiu, Zhihuang; Chen, Liangwan; Chen, Daozhong; Chen, Qiang


    Background The aim of this study was to investigate the incidence and immediate and mid-term effects of heart valve prosthesis-patient mismatch (PPM) after mitral valve replacement using the GK bileaflet mechanical valve. Material/Methods A total of 493 cases of mechanical mitral valve replacement were performed in the departments of cardiac surgery in 7 hospitals from January 2000 to January 2008. The patients included 142 men and 351 women ages 21 to 67 (average age, 48.75). The patients were followed for 3 years after surgery. The effective orifice area index (EOAI), ≤1.2 cm2/m2, was detected during the follow-up period and was defined as PPM. The patients were assigned to either the PPM group or the non-PPM group. Finally, the preoperative, perioperative and postoperative indexes of the 2 groups of patients were compared. Results A total of 157 patients had PPM 3 years after surgery. The incidence of PPM was 31.84%. Sixty-three patients in the PPM group received a 25-mm GK bileaflet valve (40.13%), 82 received a 27-mm valve (52.23%), and 12 (7.64%) received a 29-mm valve. There were significant differences in length of intensive care unit stay, duration of ventilator use, length of hospitalization, body surface area, EOAI, mean transmitral pressure gradient, and pulmonary artery pressure between the PPM and non-PPM group (P0.05). Conclusions PPM after mitral valve replacement influences postoperative hemodynamics. Thus, larger-sized GK bileaflet mechanical valves are often used to reduce the risk of PPM. PMID:26313311

  17. Coordinating Robot Teams for Disaster Relief


    Coordinating Robot Teams for Disaster Relief Mark Roberts1, Thomas Apker2, Benjamin Johnson1, Bryan Auslander3, Briana Wellman4 & David W...for Humanitarian Assistance / Disaster Relief operations. We demonstrate that the SDP responds to a dynamic, open world while ensuring that vehicles...facilitate such information gathering tasks, freeing humans to perform more critical tasks in Humanitarian Assistance / Disaster Relief (HA/DR

  18. Transcatheter Aortic Valve Replacement in Bicuspid Aortic Valve Disease

    Mylotte, Darren; Lefevre, Thierry; Søndergaard, Lars


    BACKGROUND: Limited information exists describing the results of transcatheter aortic valve (TAV) replacement in patients with bicuspid aortic valve (BAV) disease (TAV-in-BAV). OBJECTIVES: This study sought to evaluate clinical outcomes of a large cohort of patients undergoing TAV-in-BAV. METHODS...

  19. Prosthetic valve endocarditis after transcatheter aortic valve implantation

    Olsen, Niels Thue; De Backer, Ole; Thyregod, Hans G H


    risk factors. METHODS AND RESULTS: Observational single-center study of 509 consecutive patients treated with a transcatheter implanted self-expandable aortic valve prosthesis (Medtronic CoreValve). We identified 18 patients diagnosed with TAVI-PVE during a median follow-up period of 1.4 years...

  20. A sigh of relief or a sigh of expected relief: Sigh rate in response to dyspnea relief.

    Vlemincx, Elke; Meulders, Michel; Luminet, Olivier


    Research has suggested that sighs may serve a regulatory function during stress and emotions by facilitating relief. Evidence supports the hypotheses that sighs both express and induce relief from stress. To explore the potential role of sighs in the regulation of symptoms, the present study aimed to investigate the relationship between sighs and relief of symptoms, and relief of dyspnea, specifically. Healthy volunteers participated in two studies (N = 44, N = 47) in which dyspnea was induced by mild (10 cmH2 O/l/s) or high (20 cmH2 0/l/s) inspiratory resistances. Dyspnea relief was induced by the offset of the inspiratory resistances (transitions from high and mild inspiratory resistance to no resistance). Control comparisons included dyspnea increases (transitions from no or mild inspiratory resistance to high inspiratory resistance) and dyspnea continuations (continuations of either no resistance or a high resistance). In Experiment 1, dyspnea levels were cued. In Experiment 2, no cues were provided. Sigh rate during dyspnea relief was significantly higher compared to control conditions, and sigh rate increased as self-reported dyspnea decreased. Additionally, sigh rate was higher during cued dyspnea relief compared to noncued dyspnea relief. These results suggest that sighs are important markers of dyspnea relief. Moreover, sighs may importantly express dyspnea relief, as they are related to experiential dyspnea decreases and occur more frequently during expected dyspnea relief. These findings suggest that sighs may not only be important in the regulation of stress and emotions, but also may be functional in the regulation of dyspnea. © 2017 Society for Psychophysiological Research.

  1. High Reliability Cryogenic Piezoelectric Valve Actuator Project

    National Aeronautics and Space Administration — Cryogenic fluid valves are subject to harsh exposure and actuators to drive these valves require robust performance and high reliability. DSM's piezoelectric...

  2. Curved butterfly bileaflet prosthetic cardiac valve

    McQueen, David M.; Peskin, Charles S.


    An annular valve body having a central passageway for the flow of blood therethrough with two curved leaflets each of which is pivotally supported on an accentric positioned axis in the central passageway for moving between a closed position and an open position. The leaflets are curved in a plane normal to the eccentric axis and positioned with the convex side of the leaflets facing each other when the leaflets are in the open position. Various parameters such as the curvature of the leaflets, the location of the eccentric axis, and the maximum opening angle of the leaflets are optimized according to the following performance criteria: maximize the minimum peak velocity through the valve, maximize the net stroke volume, and minimize the mean forward pressure difference, thereby reducing thrombosis and improving the hemodynamic performance.

  3. Bireactor Electronuclear Systems with Liquid Cadmium Valve

    Bznuni, S A; Zhamkochyan, V M; ASosnin, A N; Polanski, A; Khudaverdyan, A H


    Three main types of bireactor electronuclear systems are discussed. From the point of view of assuring high level of functional characteristics and safety bireactor electronuclear systems with booster using enriched uranium (20 %) and with a liquid cadmium valve appears to be the most effective. It is shown by means of Monte-Carlo modeling that such operation conditions can be achieved which lead to the destruction of the intermediate cadmium layer making the systems supercritical (k_{eff}>1). One can avoid the problem by using a special design of the liquid cadmium valve. In comparison with other nuclear systems (critical reactors, one-reactor electronuclear systems) cascade electronuclear systems have essential advantages allowing the decrease of the proton beam current by one order of magnitude and providing at same time the necessary level of power generation and neutron flux. Availability of both the thermal and fast cones allows one to transmute not only transuranics but also the fission products - cesi...

  4. Does pain relief by CT-guided indirect cervical nerve root injection with local anesthetics and steroids predict pain relief after decompression surgery for cervical nerve root compression?

    Antoniadis, Alexander; Dietrich, Tobias J; Farshad, Mazda


    The relationship of pain relief from a recently presented CT-guided indirect cervical nerve root injection with local anesthetics and steroids to surgical decompression as a treatment for single-level cervical radiculopathy is not clear. This retrospective study aimed to compare the immediate and 6-week post-injection effects to the short- and long-term outcomes after surgical decompression, specifically in regard to pain relief. Patients (n = 39, age 47 ± 10 years) who had undergone CT-guided indirect injection with local anesthetics and steroids as an initial treatment for single cervical nerve root radiculopathy and who subsequently needed surgical decompression were included retrospectively. Pain levels (VAS scores) were monitored before, immediately after, and 6 weeks after injection (n = 34), as well as 6 weeks (n = 38) and a mean of 25 months (SD ± 12) after surgical decompression (n = 36). Correlation analysis was performed to find potential associations of pain relief after injection and after surgery to investigate the predictive value of post-injection pain relief. There was no correlation between immediate pain relief after injection (-32 ± 27 %) and 6 weeks later (-7 ± 19 %), (r = -0.023, p = 0.900). There was an association by tendency between immediate pain relief after injection and post-surgical pain relief at 6 weeks (-82 ± 27 %), (r = 0.28, p = 0.08). Pain relief at follow-up remained high at -70 ± 21 % and was correlated with the immediate pain amelioration effect of the injection (r = 0.37, p = 0.032). Five out of seven patients who reported no pain relief from injection had a pain relief from surgery in excess of 50 %. The amount of immediate radiculopathic pain relief after indirect cervical nerve root injection is associated with the amount of pain relief achieved at long-term follow-up after surgical decompression of single-level cervical radiculopathy

  5. Incidence and predictors of headache relief after endovascular treatment in patients with unruptured intracranial aneurysms.

    Ji, Wenjun; Liu, Aihua; Yang, Xinjian; Li, Youxiang; Jiang, Chuhan; Wu, Zhongxue


    Objective Patients with unruptured intracranial aneurysms often present with headaches. We retrospectively determined the incidence of headache relief in patients with unruptured intracranial aneurysms after endovascular treatment, with the main goals of preventing aneurysmal haemorrhage and identifying factors associated with headache relief in a cohort study. Methods From a cohort of patients with unruptured intracranial aneurysms who were treated with endovascular coiling and admitted between January 2012 and December 2014, we included 123 patients who had headaches and underwent regular follow-up. The severity of headache was assessed by a quantitative 11-point headache scale for all patients before and after the endovascular treatment. Headache relief was defined as a decrease in the headache score. We determined the incidence and predictors of headache relief using Kaplan-Meier curves and Cox regression analysis. Results Of the 123 patients with a mean follow-up of 14.1 months (range 1-39 months), 69 had headache relief. The overall cumulative incidence of headache relief was 62.3% (95% confidence interval (CI) 54.2%, 69.4%). On multivariate Cox regression analysis, the side of headache ipsilateral to the aneurysm (adjusted hazard ratio 0.540; 95% CI 0.408, 0.715; P relief. Conclusions Endovascular treatment relieved preoperative headaches for most patients with unruptured intracranial aneurysms. The side of headache ipsilateral to the aneurysm and aneurysm size >10 mm were significant predictors of headache relief.

  6. Risk Factors for Late Aortic Valve Dysfunction After the David V Valve-Sparing Root Replacement.

    Esaki, Jiro; Leshnower, Bradley G; Binongo, Jose N; Lasanajak, Yi; McPherson, LaRonica; Guyton, Robert A; Chen, Edward P


    Valve-sparing root replacement (VSRR) is an established therapy for aortic root pathology. However, late aortic valve dysfunction requiring reoperation remains a primary concern of this procedure. This study examines risk factors for late aortic insufficiency (AI) and aortic stenosis (AS) after David V VSRR. A retrospective review from 2005 to 2015 at a US academic center identified 282 patients who underwent VSRR. Cox proportional hazards regression analysis was used to identify risk factors for late AI and AS after VSRR. The mean age was 46.4 years. Sixty-four patients (22.7%) had bicuspid valves, and 41 patients (14.5%) had Marfan syndrome. The incidence of reoperations was 27 (9.6%), and 42 cases (14.9%) presented with acute type A dissection. Operative mortality was 8 (2.8%). Seven-year survival was 90.9%. Seven-year cumulative incidence of reoperation, greater than 2+ AI and greater than moderate AS were 3.1%, 2.2%, and 0.8%, respectively. Multivariable analysis showed aortic root size 55 mm or larger (hazard ratio 3.44, 95% confidence interval: 1.27 to 9.29, p = 0.01) to be a risk factor for late AI whereas bicuspid valve (hazard ratio 16.07, 95% confidence interval: 3.12 to 82.68, p = 0.001) and cusp repair were found to be risk factors (hazard ratio 5.91, 95% confidence interval: 1.17 to 29.86, p = 0.03) for late AS. Valve-sparing root replacement can be performed with low operative risk and good overall long-term survival even in complex clinical settings. Durable valve function can be expected; however, aortic root size 55 cm or more, bicuspid valve anatomy, and cusp repair represent independent risk factors for late aortic valve dysfunction after these procedures. Copyright © 2017 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.

  7. Valve morphology effect in aortic coarctation flow using realistic silicon models and magnetic resonance imaging

    Marrufo, Oscar; Solis-Najera, Sergio; Pibarot, Philippe; Kadem, Lyes; Kesharvarz-Motamed, Zahra; Rodriguez, Alfredo O.; Garcia, Julio


    Aortic valve morphology and phenotype may alter the aortic wall structure and its normal flow hemodynamics. However, the relationship between altered flow patterns and progression of wall pathology is often not fully understood in patients with aortic coartation and needs larger experimental work. In this study, we introduced a compatible experimental setup with magnetic resonance imaging (MRI) using a realistic aortic coarctation (AoCo) silicon model which can replicate physiological flow conditions (pressure, flow-wave, and systemic load). We evaluated the aortic valve hemodynamics of a normal tricuspid valve and a stenotic bicuspid valve using valve effective orifice area (EOA), peak and mean transvalvular pressure gradient (TPG). AoCo severity was assessed by the AoCo pressure gradient. For the tricuspid valve we obtained an EOA = 1.89 cm2, a peak TPG = 10 mmHg, and a mean TPG = 5 mmHg. For the bicuspid valve we obtained an EOA = 1.03 cm2, a peak TPG = 37 mmHg and a mean TPG = 13 mmHg. Furthermore, AoCo with tricuspid valve led to a peak AoCo pressure gradient (PG) = 11 mmHg and a mean PG = 5 mmHg. AoCo with bicuspid valve led to a peak PG = 6 mmHg and a mean PG = 3 mmHg. Aortic flow reattachment was more evident in presence of bicuspid valve and helical flow was present in all cases. This study showed that silicon prototyping in combination with MRI velocity measurements could successfully be used to assess hemodynamic effects of aortic valve morphology in aortic coarctation flow.

  8. Aortic valve replacement in octogenarians

    Dark John H


    Full Text Available Abstract Background and Aims As our population ages and life expectancy increases the number of people aged over 80 and more referred for cardiac surgery is growing. This study sought to identify the outcome of aortic valve replacement (AVR in octogenarians. Methods 68 patients aged 80 years or more underwent AVR at the Freeman Hospital, between April 2001 and April 2004. A retrospective review of the notes and outcomes from the patients' GP and the NHS strategic tracking service was performed. 54% (37 underwent isolated AVR whilst 46% (31 underwent combined AVR and CABG. Results Follow up was 100% complete. The mean age was 83.1 ± s.d. 2.9 years, a mean gradient of 83 ± s.d. 31 mmHg and mean AVA of 0.56 cm2. The mean additive EuroSCORE was 8.6 ± s.d. 1.2, the logistic EuroSCORE mean 12.0 ± s.d. 5.9. In hospital 30 day mortality was 13 %. Survival was 80% at 1 year and 78% at 2 years. Median follow up was for 712 days. Stepwise logistic regression identified chronic obstructive airways disease as an independent predictor of mortality (p Conclusion Our study demonstrates that the operative mortality for AVR in the over eighties is good, whilst the mid to long term outcome is excellent There is a very low attrition rate with those undergoing the procedure living as long than their age matched population. This study confirms AVR is a safe, acceptable treatment for octogenarians with excellent mid term outcomes.

  9. Surge-damping vacuum valve

    Bullock, Jack C.; Kelly, Benjamin E.


    A valve having a mechanism for damping out flow surges in a vacuum system which utilizes a slotted spring-loaded disk positioned adjacent the valve's vacuum port. Under flow surge conditions, the differential pressure forces the disk into sealing engagement with the vacuum port, thereby restricting the flow path to the slots in the disk damping out the flow surge.

  10. Mitral valve surgery - minimally invasive

    ... Saunders; 2012:chap 61. Otto CM, Bonow RO. Valvular heart disease. In: Mann DL, Zipes DP, Libby P, Bonow ... Editorial team. Related MedlinePlus Health Topics Heart Surgery Heart Valve Diseases Mitral Valve Prolapse Browse the Encyclopedia A.D. ...

  11. Combination throttle and shutoff valve

    Carriker, J. W.


    Combination of translating sleeve throttle valve and conventional poppet valve provides capability of shutting off flow completely by poppet and sleeve control of the rate of flow. Integration of the two concepts can be accomplished without difficulty and in a manner that requires a minimum of development.

  12. Variable gas leak rate valve

    Eernisse, Errol P. (Albuquerque, NM); Peterson, Gary D. (Albuquerque, NM)


    A variable gas leak rate valve which utilizes a poled piezoelectric element to control opening and closing of the valve. The gas flow may be around a cylindrical rod with a tubular piezoelectric member encircling the rod for seating thereagainst to block passage of gas and for reopening thereof upon application of suitable electrical fields.

  13. [The assessment of mechanical heart valves stenosis in adults after aortic valve replacement: the advantage of full-flow design of mechanical valve].

    Bokeria, L A; Bokeria, O L; Fadeev, A A; Makhachev, O A; Kosareva, T I; Averina, I I


    The analysis of transprosthetic hemodynamics in adults after aortic valve replacement in the Bakoulev Center for Cardiovascular Surgery in 2007-2010 demonstrated the hemodynamic advantage of the concept of new full-flow mechanical aortic valve prosthesis "CorBeat". Having the same size of internal orifice and tissue annulus diameters, the values of transprosthetic parameters (peak and mean gradients, blood flow velocities) through "CorBeat" were close to physiological values of transvalvular native aortic parameters and had a tendency to be not dependent on the size of prosthesis (p = 0.63). In the article for the first time a morphometric database of geometric values of internal orifice area of normal native aortic valves in adults was used taking into account both the gender and the body surface area's of a patient. There was also used the standardized prosthesis size Z-score which represents the number of SDs by which the internal prosthesis area differs from the mean normal native aortic valve area for the patient's body surface area. The article emphasizes the need of the personal selection of the size and the type of prosthesis for any patient as well as the need for new design development of prosthetic heart valves.

  14. Oxycodone combinations for pain relief.

    Raffa, R B; Pergolizzi, J V; Segarnick, D J; Tallarida, R J


    No single analgesic drug provides the perfect therapeutic/adverse effect profile for every pain condition. In addition to convenience and possibly improved compliance, a combination of analgesic drugs offers the potential, requiring verification, of providing greater pain relief and/or reduced adverse effects than the constituent drugs when used individually. We review here analgesic combinations containing oxycodone. We found surprisingly little preclinical information about the analgesic or adverse effect profiles of the combinations (with acetaminophen, paracetamol, nonsteroidal anti-inflammatory drugs, morphine, gabapentin or pregabalin). Clinical experience and studies suggest that the combinations are safe and effective and may offer certain advantages. As with all combinations, the profile of adverse effects must also be determined in order to provide the clinician with the overall benefit/risk assessment.

  15. Exercise Based- Pain Relief Program

    Zadeh, Mahdi Hossein

    in the current study was to use exercise induced- muscle damage followed by ECC as an acute pain model and observe its effects on the sensitivity of the nociceptive system and blood supply in healthy subjects. Then, the effect of a repeated bout of the same exercise as a healthy pain relief strategy......Exercise-based pain management programs are suggested for relieving from musculoskeletal pain; however the pain experienced after unaccustomed, especially eccentric exercise (ECC) alters people´s ability to participate in therapeutic exercises. Subsequent muscle pain after ECC has been shown...... to cause localized pressure pain and hyperalgesia. A prior bout of ECC has been repeatedly reported to produce a protective adaptation known as repeated bout effect (RBE). One of the main scopes of the current project was to investigate the adaptations by which the RBE can be resulted from. The approach...

  16. Pain relief can be painful

    Ashish Bindra


    Full Text Available Mandibular nerve block is periodically used procedure used to treat neuralgic pain in the distribution of trigeminal nerve. It is a commonly performed block in outpatient settings at our institute. We present a case of an elderly edentulous patient with trigeminal neuralgia who suffered recurrent temporomandibular joint (TMJ dislocation following mandibular nerve block. The patient presented with complaints of severe pain, inability to close mouth, and eat food since 2 days. Anterior closed reduction of TMJ resulted in reduction of joint and immediate pain relief. However, the maneuver failed due to recurrent dislocation of the joint. A Barton dressing was applied to prevent another dislocation. This was followed by autologous blood injection into the joint. This case focuses on the preponderance of clinical evaluation and accentuates the need for additional forethought to be taken during pain procedures, particularly in the geriatric population.

  17. Experimental Validation of Mathematical Framework for Fast Switching Valves used in Digital Hydraulic Machines

    Nørgård, Christian; Roemer, Daniel Beck; Bech, Michael Møller


    A prototype of a fast switching valve designed for a digital hydraulic transmission has been manufactured and experimentally tested. The valve is an annular seat valve composed of a plunger connected with a direct electromagnetic moving coil actuator as the force producing element. Based on an el......A prototype of a fast switching valve designed for a digital hydraulic transmission has been manufactured and experimentally tested. The valve is an annular seat valve composed of a plunger connected with a direct electromagnetic moving coil actuator as the force producing element. Based...... of 10 kW during switching (mean of approximately 250 W) and a pressure loss below 0.5 bar at 600 l/min. The main goal of this article is validate parts of the mathematical framework based on a series of experiments. Furthermore, this article aims to document the experience gained from the experimental...... work and to study and assess a moving coil actuators suitability for the application....

  18. Fluid mechanics of artificial heart valves.

    Dasi, Lakshmi P; Simon, Helene A; Sucosky, Philippe; Yoganathan, Ajit P


    1. Artificial heart valves have been in use for over five decades to replace diseased heart valves. Since the first heart valve replacement performed with a caged-ball valve, more than 50 valve designs have been developed, differing principally in valve geometry, number of leaflets and material. To date, all artificial heart valves are plagued with complications associated with haemolysis, coagulation for mechanical heart valves and leaflet tearing for tissue-based valve prosthesis. For mechanical heart valves, these complications are believed to be associated with non-physiological blood flow patterns. 2. In the present review, we provide a bird's-eye view of fluid mechanics for the major artificial heart valve types and highlight how the engineering approach has shaped this rapidly diversifying area of research. 3. Mechanical heart valve designs have evolved significantly, with the most recent designs providing relatively superior haemodynamics with very low aerodynamic resistance. However, high shearing of blood cells and platelets still pose significant design challenges and patients must undergo life-long anticoagulation therapy. Bioprosthetic or tissue valves do not require anticoagulants due to their distinct similarity to the native valve geometry and haemodynamics, but many of these valves fail structurally within the first 10-15 years of implantation. 4. These shortcomings have directed present and future research in three main directions in attempts to design superior artificial valves: (i) engineering living tissue heart valves; (ii) development of advanced computational tools; and (iii) blood experiments to establish the link between flow and blood damage.

  19. 安全阀的调试与维修%Debugging and Maintenance of Safety Valve



    This paper briefly describes the SY type safety valve application in petrochemical industry, as well as the role of the relief valve in the production unit is responsible for. Relief valve set point of the set is a dangerous and necessary work very much, because the work of specific data, will reflect to the relief valve in the device usage, directly determines the safety valve will be able to have the corresponding security protection. The thesis gives a set of production site pressure setting debugging methods, combined with field using the process of maintenance and repair work experience, summed up the various common faults and fault processing methods, some and illustrates the maintenance process should pay attention to the aspects.%本文简要叙述了SY型安全阀在石油化工行业中的一些应用,以及安全阀在生产装置中所担负的作用。安全阀设定值的现场设定是一项危险且非常必要的工作,因为这一工作得出的具体数据,将体现到其在装置中的使用情况,且直接决定了其是否能够起到相应的安全保护作用。本文详细给出了生产现场压力设定值的设定调试的具体方法,结合现场使用过程中运行维护和检修的工作经验,总结了各种常见故障及其针对一些故障的处理方法,并说明了检修过程中应该注意的方面。

  20. The measurement of opening angle and orifice area of a bileaflet mechanical valve using multidetector computed tomography.

    Lee, Dong-Hyeon; Youn, Ho-Joong; Shim, Sung-Bo; Lee, Sun-Hee; Jung, Jung-Im; Jung, Seung-Eun; Choi, Yun-Seok; Park, Chul-Soo; Oh, Yong-Seog; Chung, Wook-Sung; Kim, Jae-Hyung


    The aim of this study was to assess mechanical valve function using 64-slice multidetector computed tomography (MDCT). In 20 patients (mean age, 50+/-12 years; male-to-female ratio, 10:10), 30 St. Jude bileaflet mechanical valves (15 aortic and 15 mitral valves) were evaluated using MDCT. We selected images vertical and parallel to the mechanical valve. The valve orifice area (OA) and valve length were determined by manual tracing and the opening and closing angles were measured using a protractor. The OA and length of the mechanical valves were compared with the manufacturer's values. The geometric orifice areas (GOAs) based on the manufacturer's values and the OAs determined by MDCT were 3.4+/-0.2 cm(2) and 3.4+/-0.3 cm(2) for the mitral valves and 2.1+/-0.3 cm(2) and 2.1+/-0.4 cm(2) for the aortic valves, respectively. The correlation coefficients between the OA measures were 0.433 for the mitral valves and 0.874 for the aortic valves (both pvalves and 21.5+/-2.1 mm and 20.7+/-2.3 mm for the aortic valves, respectively. The correlation coefficients between the measures were 0.651 for the mitral valve and 0.846 for the aortic valve (both pvalves and 11.1+/-0.9 degrees and 120.6+/-1.7 degrees for the aortic valves, respectively. MDCT is an accurate modality with which to assess the function and morphology of bileaflet mechanical valves.

  1. 44 CFR 68.12 - Relief.


    ... 44 Emergency Management and Assistance 1 2010-10-01 2010-10-01 false Relief. 68.12 Section 68.12 Emergency Management and Assistance FEDERAL EMERGENCY MANAGEMENT AGENCY, DEPARTMENT OF HOMELAND SECURITY... Relief. The final determination may be appealed by the appellant(s) to the United States district court...

  2. 24 CFR 220.753 - Forbearance relief.


    ... 24 Housing and Urban Development 2 2010-04-01 2010-04-01 false Forbearance relief. 220.753 Section 220.753 Housing and Urban Development Regulations Relating to Housing and Urban Development (Continued... and Obligations-Projects Project Mortgage Insurance § 220.753 Forbearance relief. (a) In a case where...

  3. 47 CFR 1.6009 - Relief.


    ... 47 Telecommunication 1 2010-10-01 2010-10-01 false Relief. 1.6009 Section 1.6009 Telecommunication FEDERAL COMMUNICATIONS COMMISSION GENERAL PRACTICE AND PROCEDURE Implementation of Section 325(e) of the... Carriers for Retransmission Without Consent § 1.6009 Relief. If the Commission determines that a satellite...

  4. 24 CFR 236.255 - Forbearance relief.


    ... 24 Housing and Urban Development 2 2010-04-01 2010-04-01 false Forbearance relief. 236.255 Section 236.255 Housing and Urban Development Regulations Relating to Housing and Urban Development (Continued... Insurance § 236.255 Forbearance relief. (a) In a case where the mortgage is in default, the mortgagor and...

  5. 24 CFR 221.761 - Forbearance relief.


    ... 24 Housing and Urban Development 2 2010-04-01 2010-04-01 false Forbearance relief. 221.761 Section 221.761 Housing and Urban Development Regulations Relating to Housing and Urban Development (Continued... § 221.761 Forbearance relief. (a) In a case where the mortgage is in default, the mortgagor and the...

  6. Diagnosis and treatment of early bioprosthetic malfunction in the mitral valve position due to thrombus formation.

    Butnaru, Adi; Shaheen, Joseph; Tzivoni, Dan; Tauber, Rachel; Bitran, Daniel; Silberman, Shuli


    Bioprosthetic valve thrombosis is uncommon and the diagnosis is often elusive and may be confused with valve degeneration. We report our experience with mitral bioprosthetic valve thrombosis and suggest a therapeutic approach. From 2002 to 2011, 149 consecutive patients who underwent mitral valve replacement with a bioprosthesis at a single center were retrospectively screened for clinical or echocardiographic evidence of valve malfunction. Nine were found to have valve thrombus. All 9 patients had their native valve preserved, representing 24% of those with preserved native valves. Five patients (group 1) presented with symptoms of congestive heart failure at 16.4 ± 12.4 months after surgery. Echocardiogram revealed homogenous echo-dense film on the ventricular surface of the bioprosthesis with elevated transvalvular gradient, resembling early degeneration. The first 2 patients underwent reoperation: valve thrombus was found and confirmed by histologic examination. Based on these, the subsequent 3 patients received anticoagulation treatment with complete thrombus resolution: mean mitral gradient decreased from 23 ± 4 to 6 ± 1 mm Hg and tricuspid regurgitation gradient decreased from 83 ± 20 to 49 ± 5 mm Hg. Four patients (group 2) were asymptomatic, but routine echocardiogram showed a discrete mass on the ventricular aspect of the valve: 1 underwent reoperation to replace the valve and 3 received anticoagulation with complete resolution of the echocardiographic findings. In conclusion, bioprosthetic mitral thrombosis occurs in about 6% of cases. In our experience, onset is early, before anticipated valve degeneration. Clinical awareness followed by an initial trial with anticoagulation is warranted. Surgery should be reserved for those who are not responsive or patients in whom the hemodynamic status does not allow delay. Nonresection of the native valve at the initial operation may play a role in the origin of this entity.

  7. Robotic mitral valve surgery.

    Kypson, Alan P; Nifong, L Wiley; Chitwood, W Randolph


    A renaissance in cardiac surgery has begun. The early clinical experience with computer-enhanced telemanipulation systems outlines the limitations of this approach despite some procedural success. Technologic advancements, such as the use of nitinol U-clips (Coalescent Surgical Inc., Sunnyvale, CA) instead of sutures requiring manual knot tying, have been shown to decrease operative times significantly. It is expected that with further refinements and development of adjunct technologies, the technique of computer-enhanced endoscopic cardiac surgery will evolve and may prove to be beneficial for many patients. Robotic technology has provided benefits to cardiac surgery. With improved optics and instrumentation, incisions are smaller. The ergometric movements and simulated three-dimensional optics project hand-eye coordination for the surgeon. The placement of the wristlike articulations at the end of the instruments moves the pivoting action to the plane of the mitral annulus. This improves dexterity in tight spaces and allows for ambidextrous suture placement. Sutures can be placed more accurately because of tremor filtration and high-resolution video magnification. Furthermore, the robotic system may have potential as an educational tool. In the near future, surgical vision and training systems might be able to model most surgical procedures through immersive technology. Thus, a "flight simulator" concept emerges where surgeons may be able to practice and perform the operation without a patient. Already, effective curricula for training teams in robotic surgery exist. Nevertheless, certain constraints continue to limit the advancement to a totally endoscopic computer-enhanced mitral valve operation. The current size of the instruments, intrathoracic instrument collisions, and extrathoracic "elbow" conflicts still can limit dexterity. When smaller instruments are developed, these restraints may be resolved. Furthermore, a working port incision is still required for

  8. Valve-related complications after mechanical heart valve implantation.

    Misawa, Yoshio


    The number of heart valve surgeries is increasing, and 19,164 patients underwent heart valve surgery in Japan in 2011. The early mortality rate has remained stable for more than 10 years. Many patients now survive for many years, with a reported 10-year survival rate of at least 60 %. However, unfavorable complications can occur after valve surgery. Valve-related complications include thromboembolisms, bleeding complications and prosthetic valve endocarditis, followed by structural and nonstructural prosthetic valve dysfunctions. Our review of studies published after 2000 revealed that the rate of all valve-related complications was 0.7-3.5 % per patient-year. Thromboembolisms occur at a rate of approximately 1 % per patient-year, and bleeding complications occur at almost 0.5 % per patient-year. Thromboembolic and hemorrhagic events related to anticoagulant therapy should be considered during life-long follow-up. The occurrence rate of endocarditis reaches 0.5 % per patient-year, with a poor postoperative survival. Structural dysfunctions have been largely overcome, and the nonstructural dysfunction rate is 0.4-1.2 % per patient-year. The nonstructural dysfunctions induced by paravalvular leaks and pannus ingrowth are also issues that need to be resolved.

  9. Patents and heart valve surgery - II: tissue valves.

    Cheema, Faisal H; Kossar, Alexander P; Rehman, Atiq; Younas, Fahad; Polvani, Gianluca


    Valvular heart disease affects millions of Americans yearly and currently requires surgical intervention to repair or replace the defective valves. Through a close-knit collaboration between physicians, scientists and biomedical engineers, a vast degree of research and development has been aimed towards the optimization of prosthetic heart valves. Although various methods have made fantastic strides in producing durable prostheses, the therapeutic efficacy of prosthetic valves is inherently limited by a dependency upon lifelong anticoagulant regimens for recipients - a difficult challenge for many in clinical setting. Thus, biological tissue valves have been developed to circumvent vascular and immunemediated complications by incorporating biological materials to mimic native valves while still maintaining a necessary level of structural integrity. Over the past decade, a multitude of patents pertaining to the refinement of designs as well as the advancement in methodologies and technologies associated with biological tissue valves have been issued. This review seeks to chronicle and characterize such patents in an effort to track the past, present, and future progress as well as project the trajectory of tissue valves in the years to come.

  10. Internal Acoustics of a Pintle Valve with Supercritical Helium Flow

    Fishbach, Sean R.; Davis, R. Benjamin


    Large amplitude flow unsteadiness is a common phenomenon within the high flow rate ducts and valves associated with propulsion systems. Boundary layer noise, shear layers and vortex shedding are a few of the many sources of flow oscillations. The presence of lightly damped acoustic modes can organize and amplify these sources of flow perturbation, causing undesirable loading of internal parts. The present study investigates the self-induced acoustic environment within a pintle valve subject to high Reynolds Number flow of helium gas. Experiments were conducted to measure the internal pressure oscillations of the Ares I Launch Abort System (LAS) Attitude Control Motor (ACM) valve. The AGM consists of a solid propellant gas generator with eight pintle valves attached to the aft end. The pintle valve is designed to deliver variable upstream conditions to an attache( converging diverging nozzle. In order to investigate the full range of operating conditions 28 separate tests were conducted with varying pintle position and upstream pressure. Helium gas was utilized in order to closely mimic the speed of sound of the gas generator exhaust, minimizing required scaling during data analysis. The recordec pressure measurements were interrogated to multiple ends. The development of root mean square (RMS) value! versus Reynolds Number and Pintle position are important to creating bounding unsteady load curves for valve internal parts. Spectral analysis was also performed, helping to identify power spectral densities (PSD) of acoustic natural frequencies and boundary layer noise. An interesting and unexpected result was the identification of an acoustic mode within the valve which does not respond until the valve was over 60% open. Further, the response amplitude around this mode can be as large or larger than those associated with lower frequency modes.

  11. Self-Rupturing Hermetic Valve

    Tucker, Curtis E., Jr.; Sherrit, Stewart


    For commercial, military, and aerospace applications, low-cost, small, reliable, and lightweight gas and liquid hermetically sealed valves with post initiation on/off capability are highly desirable for pressurized systems. Applications include remote fire suppression, single-use system-pressurization systems, spacecraft propellant systems, and in situ instruments. Current pyrotechnic- activated rupture disk hermetic valves were designed for physically larger systems and are heavy and integrate poorly with portable equipment, aircraft, and small spacecraft and instrument systems. Additionally, current pyrotechnically activated systems impart high g-force shock loads to surrounding components and structures, which increase the risk of damage and can require additional mitigation. The disclosed mechanism addresses the need for producing a hermetically sealed micro-isolation valve for low and high pressure for commercial, aerospace, and spacecraft applications. High-precision electrical discharge machining (EDM) parts allow for the machining of mated parts with gaps less than a thousandth of an inch. These high-precision parts are used to support against pressure and extrusion, a thin hermetically welded diaphragm. This diaphragm ruptures from a pressure differential when the support is removed and/or when the plunger is forced against the diaphragm. With the addition of conventional seals to the plunger and a two-way actuator, a derivative of this design would allow nonhermetic use as an on/off or metering valve after the initial rupturing of the hermetic sealing disk. In addition, in a single-use hermetically sealed isolation valve, the valve can be activated without the use of potential leak-inducing valve body penetrations. One implementation of this technology is a high-pressure, high-flow-rate rupture valve that is self-rupturing, which is advantageous for high-pressure applications such as gas isolation valves. Once initiated, this technology is self

  12. Attenuating water hammer pressure by means of gas storage tank


    The basic equations for computing the volume of gas storage tank were derived from the principles of attenuating water hammer pressure. Verifications using experiments indicate that the proposed equation can provide a fare precision in the predictions. By using the model of solid-liquid two-phase flow, the gas storage tank, pressure-relief valves and slow-closure reverse-control valves were compared with practical engineering problems, and the functions of gas storage tank in attenuating water hammer pressure were further investigated.

  13. Histopathological study of congenital aortic valve malformations in 32 children

    HUANG Ping; WANG Hongwei; LI Yanping; CHENG Peixuan; LIU Qingjun; ZHANG Zhenlu; LIU Jianying


    The histopathological characteristics of congenital aortic valve malformations in children were investigated.All the native surgically excised aortic valves from 32 pediatric patients suffering from symptomatic aortic valve dysfunction due to congenital aortic valve malformations between January 2003 and December 2005 were studied macroscopically and microscopically.The patients' medical records were reviewed and the clinical information was extracted.The diagnosis was made by the clinical presentation,preoperative echocardiography,intraoperative examination,and postoperative histopathological study,excluding rheumatic ot degenerative aortic valve diseases,infective endocarditis and primary connective tissue disorders,e.g.Marfan syndrome.Among 32 children with congenital aortic valve malformations,the age was ranged from six to 18 years,with a mean of 14.9 years,and there were 27 boys and five girls (male:female = 5.4:1).There were five cases of aortic stenosis (AS,15.62%),25 cases of aortic insufficiency (AI,78.13 %)and two cases of AS-AI (6.25%),without other valve diseases.Twenty cases still had other congenital heart diseases:ventricular septal defect (19 cases),patent ductus arteriosus (two cases),double-chambered right ventricle (one case),aneurysm of the right anterior aortic sinus of valsalva (three cases).Histopathological examination indicated that the cusps became thickening with unequal size,irregular shape (coiling and prolapse edge),enhanced hardness,and partly calcification.Microscopic investigation revealed the unsharp structure of valve tissue,fibrosis,myxomatous,reduced collagen fiber,rupture of elastic fibers,different degrees of infiltration of inflammatory cells,secondary calcareous and lipid deposit,and secondary fibrosis.Congenital aortic valve malformations in children involve males more than females,mostly associated with other congenital heart diseases.Aortic insufficiency is more common in children with congenital aortic valve

  14. 42 CFR 84.137 - Inhalation and exhalation valves; check valves; minimum requirements.


    ... 42 Public Health 1 2010-10-01 2010-10-01 false Inhalation and exhalation valves; check valves... PROTECTIVE DEVICES Supplied-Air Respirators § 84.137 Inhalation and exhalation valves; check valves; minimum requirements. (a) Inhalation and exhalation valves shall be provided where necessary and protected...

  15. 49 CFR 195.116 - Valves.


    ... 49 Transportation 3 2010-10-01 2010-10-01 false Valves. 195.116 Section 195.116 Transportation... PIPELINE Design Requirements § 195.116 Valves. Each valve installed in a pipeline system must comply with the following: (a) The valve must be of a sound engineering design. (b) Materials subject to...

  16. 14 CFR 125.133 - Fuel valves.


    ... 14 Aeronautics and Space 3 2010-01-01 2010-01-01 false Fuel valves. 125.133 Section 125.133....133 Fuel valves. Each fuel valve must— (a) Comply with § 125.155; (b) Have positive stops or suitable... operation or from accelerated flight conditions are not transmitted to the lines connected to the valve....

  17. 49 CFR 192.145 - Valves.


    ... 49 Transportation 3 2010-10-01 2010-10-01 false Valves. 192.145 Section 192.145 Transportation... BY PIPELINE: MINIMUM FEDERAL SAFETY STANDARDS Design of Pipeline Components § 192.145 Valves. (a) Except for cast iron and plastic valves, each valve must meet the minimum requirements of API...

  18. Cavitation guide for control valves

    Tullis, J.P. [Tullis Engineering Consultants, Logan, UT (United States)


    This guide teaches the basic fundamentals of cavitation to provide the reader with an understanding of what causes cavitation, when it occurs, and the potential problems cavitation can cause to a valve and piping system. The document provides guidelines for understanding how to reduce the cavitation and/or select control valves for a cavitating system. The guide provides a method for predicting the cavitation intensity of control valves, and how the effect of cavitation on a system will vary with valve type, valve function, valve size, operating pressure, duration of operation and details of the piping installation. The guide defines six cavitation limits identifying cavitation intensities ranging from inception to the maximum intensity possible. The intensity of the cavitation at each limit Is described, including a brief discussion of how each level of cavitation influences the valve and system. Examples are included to demonstrate how to apply the method, including making both size and pressure scale effects corrections. Methods of controlling cavitation are discussed providing information on various techniques which can be used to design a new system or modify an existing one so it can operate at a desired level of cavitation.

  19. Quantification of aortic valve area at 256-slice computed tomography: Comparison with transesophageal echocardiography and cardiac catheterization in subjects with high-grade aortic valve stenosis prior to percutaneous valve replacement

    Klass, Oliver, E-mail: [University Hospital of Ulm, Department of Diagnostic and Interventional Radiology, Steinhoevelstr. 9, 89075 Ulm (Germany); Walker, Matthew J.; Olszewski, Mark E. [Philips Healthcare, CT Clinical Science, Cleveland, OH (United States); Bahner, Johannes; Feuerlein, Sebastian; Hoffmann, Martin H.K.; Lang, Alexandra [University Hospital of Ulm, Department of Diagnostic and Interventional Radiology, Steinhoevelstr. 9, 89075 Ulm (Germany)


    Purpose: The purpose of this study was to compare planimetric aortic valve area (AVA) measurements from 256-slice CT to those derived from transesophageal echocardiography (TEE) and cardiac catheterization in high-risk subjects with known high-grade calcified aortic stenosis. Methods and materials: The study included 26 subjects (10 males, mean age: 79 {+-} 6; range, 61-88 years). All subjects were clinically referred for aortic valve imaging prior to percutaneous aortic valve replacement from April 2008 to March 2009. Two radiologists, blinded to the results of TEE and cardiac catheterization, independently selected the systolic cardiac phase of maximum aortic valve area and independently performed manual CT AVA planimetry for all subjects. Repeated AVA measurements were made to establish CT intra- and interobserver repeatability. In addition, the image quality of the aortic valve was rated by both observers. Aortic valve calcification was also quantified. Results: All 26 subjects had a high-grade aortic valve stenosis (systolic opening area <1.0 cm{sup 2}) via CT-based planimetry, with a mean AVA of 0.62 {+-} 0.18. In four subjects, TEE planimetry was precluded due to severe aortic valve calcification, but CT-planimetry was successfully performed with a mean AVA of 0.46 {+-} 0.23 cm{sup 2}. Mean aortic valve calcium mass score was 563.8 {+-} 526.2 mg. Aortic valve area by CT was not correlated with aortic valve calcium mass score. A bias and limits of agreement among CT and TEE, CT and cardiac catheterization, and TEE and cardiac catheterization were -0.07 [-0.37 to 0.24], 0.03 [-0.49 to 0.55], 0.12 [-0.39 to 0.63] cm{sup 2}, respectively. Differences in AVA among CT and TEE or cardiac catheterization did not differ systematically over the range of measurements and were not correlated with aortic valve calcium mass score. Conclusion: Planimetric aortic valve area measurements from 256-slice CT agree well with those derived from TEE and cardiac catheterization in

  20. The Neopuff's PEEP valve is flow sensitive.

    Hawkes, Colin Patrick


    AIM: The current recommendation in setting up the Neopuff is to use a gas flow of 5-15 L\\/min. We investigated if the sensitivity of the positive end expiratory pressure (PEEP) valve varies at different flow rates within this range. METHODS: Five Neopuffs were set up to provide a PEEP of 5 cm H(2) O. The number of clockwise revolutions to complete occlusion of the PEEP valve and the mean and range of pressures at each quarter clockwise revolution were recorded at gas flow rates between 5 and 15 L\\/min. Results: At 5, 10 and 15 L\\/min, 0.5, 1.7 and 3.4 full clockwise rotations were required to completely occlude the PEEP valve, and pressures rose from 5 to 11.4, 18.4 and 21.5 cm H(2) O, respectively. At a flow rate of 5 L\\/min, half a rotation of the PEEP dial resulted in a rise in PEEP from 5 to 11.4cm H(2) O. At 10 L\\/min, half a rotation resulted in a rise from 5 to 7.7cm H(2) O, and at 15 L\\/min PEEP rose from 5 to 6.8cm H(2) O. CONCLUSION: Users of the Neopuff should be aware that the PEEP valve is more sensitive at lower flow rates and that half a rotation of the dial at 5 L\\/min gas flow can more than double the PEEP.

  1. Proportional valve with a piezoelectric actuator

    Laski, Pawel Andrzej


    The article concerns a slotted proportional valve for use in pneumatic and hydraulic systems. There is a growing demand for both hydraulic and pneumatic ultrafast proportional valves. The conducted analysis of literature confirms the lack of such solutions for proportional valves. The currently used pneumatic systems for selection and segregation of parts and objects require ultrafast valves. The presented solution for the proportional valve can significantly improve and accelerate this type of technological processes. Furthermore, fast proportional valves can be successfully used for positional control of pneumatic and hydraulic drives. The article presents the design of a slotted divide valve and sets the maximum mass flow rate for service roads.

  2. Proportional valve with a piezoelectric actuator

    Laski Pawel Andrzej


    Full Text Available The article concerns a slotted proportional valve for use in pneumatic and hydraulic systems. There is a growing demand for both hydraulic and pneumatic ultrafast proportional valves. The conducted analysis of literature confirms the lack of such solutions for proportional valves. The currently used pneumatic systems for selection and segregation of parts and objects require ultrafast valves. The presented solution for the proportional valve can significantly improve and accelerate this type of technological processes. Furthermore, fast proportional valves can be successfully used for positional control of pneumatic and hydraulic drives. The article presents the design of a slotted divide valve and sets the maximum mass flow rate for service roads.

  3. Double prosthetic aortic valve. Case report.

    Liddicoat, J E; Bekassy, S M; De Bakey, M E


    A 55-year-old man underwent insection of a Hufnagel valve into his descending thoracic aorta for aortic valve insufficiency 18 years ago. He remained asymptomatic for 16 years. Because of progressive left ventricular failure his incompetent aortic valve was replaced with a De Bakey carbon ball aortic valve prosthesis 2 years later. Currently, 21 months after the operation, he is doing well with two aortic valves. Review of the literature suggests that he is the first patient reported with two aortic valves functioning concomitantly and one of the longest surviving patients with a Hufnagel valve.

  4. Transcatheter, valve-in-valve transapical aortic and mitral valve implantation, in a high risk patient with aortic and mitral prosthetic valve stenoses

    Harish Ramakrishna


    Full Text Available Transcatheter valve implantation continues to grow worldwide and has been used principally for the nonsurgical management of native aortic valvular disease-as a potentially less invasive method of valve replacement in high-risk and inoperable patients with severe aortic valve stenosis. Given the burden of valvular heart disease in the general population and the increasing numbers of patients who have had previous valve operations, we are now seeing a growing number of high-risk patients presenting with prosthetic valve stenosis, who are not potential surgical candidates. For this high-risk subset transcatheter valve delivery may be the only option. Here, we present an inoperable patient with severe, prosthetic valve aortic and mitral stenosis who was successfully treated with a trans catheter based approach, with a valve-in-valve implantation procedure of both aortic and mitral valves.

  5. Marked discrepancy in pressure gradient between Doppler and catheter examinations on Medtronic Mosaic valve in aortic position.

    Ito, Toshiaki; Maekawa, Atsuo; Fujii, Genyo; Sawaki, Sadanari; Hoshino, Satoshi; Hayashi, Yasunari


    A 71-year-old woman underwent aortic valve replacement with 23 mm Medtronic Mosaic Ultra valve 4 years ago because of aortic stenosis. Although she had been asymptomatic since the operation, echocardiography showed 4 m/s of transprosthetic valve flow that implied early prosthetic valve failure. Catheter examination revealed that the mean transvalvular pressure gradient during systole was 15.1 mmHg on simultaneous pressure recording, and calculated valve area 1.82 cm(2). Her body surface area was 1.56 m(2). Prosthetic valve failure and prosthesis-patient mismatch were both denied. The discrepancy between Doppler study data and catheter data seemed to be due to fluid dynamical pressure recovery phenomenon. Net pressure difference between the left ventricle and the aorta may be significantly smaller than that estimated using Bernoulli's equation from transvalvular flow speed in some patients after aortic valve replacement.

  6. The Lifetime of the Biplane Disc by using the Mean Stress Theory

    Cristian Marius Mimis; Tiberiu Stefan Manescu; Razvan Avram


    Butterfly valves in hydroelectric scheme are safety elements that ensure tightly closed access water into downstream equipment. The operation conditions of the biplane disc butterfly valve are subjected to cycles of varying loads. The paper present the lifetime of the butterfly valve disc by using the Soderberg mean stress theory to find the minimum number of cycles which the disc can be loaded and unloaded during the operation of the butterfly valve.

  7. The Lifetime of the Biplane Disc by using the Mean Stress Theory

    Cristian Marius Mimis


    Full Text Available Butterfly valves in hydroelectric scheme are safety elements that ensure tightly closed access water into downstream equipment. The operation conditions of the biplane disc butterfly valve are subjected to cycles of varying loads. The paper present the lifetime of the butterfly valve disc by using the Soderberg mean stress theory to find the minimum number of cycles which the disc can be loaded and unloaded during the operation of the butterfly valve.

  8. Human tissue valves in aortic position: determinants of reoperation and valve regurgitation

    T.P. Willems (Tineke); E.W. Steyerberg (Ewout); V.E. Kleyburg-Linkers; E. Bos (Egbert); L.A. van Herwerden (Lex); J.R.T.C. Roelandt (Jos); J.J.M. Takkenberg (Hanneke)


    textabstractBACKGROUND: Human tissue valves for aortic valve replacement have a limited durability that is influenced by interrelated determinants. Hierarchical linear modeling was used to analyze the relation between these determinants of durability and valve

  9. Comparison of outcomes after aortic valve replacement with a mechanical valve or a bioprosthesis using microsimulation

    J.P.A. Puvimanasinghe (John); M.B. Edwards; M.J.C. Eijkemans (René); E.W. Steyerberg (Ewout); L.A. van Herwerden (Lex); K.M. Taylor; G.L. Grunkemeier (Gary); J.D.F. Habbema (Dik); A.J.J.C. Bogers (Ad); J.J.M. Takkenberg (Hanneke)


    textabstractBACKGROUND: Mechanical valves and bioprostheses are widely used for aortic valve replacement. Though previous randomised studies indicate that there is no important difference in outcome after implantation with either type of valve, knowledge of outcomes after aortic va


    Yin-ping Chu; Jin-lian Cheng; Ru-kun Chen; Yu-bo Fan; Fang Pu


    Objective To assess the influence of mimic cardiac rate on hydrodynamics of different mechanical prosthetic cardiac valves.Methods US-made CarboMedics bileaflet valve, China-made Jiuling bileaflet valve and C-L tilting disc valve were tested via a pulsatile flow simulator in the aortic position. Testing conditions were set at mimic cardiac rates of 55 bpm, 75 bpm, 100bpm with a constant mimic cardiac output of 4 L/min. The mean pressure differences (△P), leakage volumes (LEV) and closing volumes (CLV) across each valve, and effective orifice areas (EOA) were analyzed.Results Within physiological range, △p, LEV, and CLV decreased as mimic cardiac rate increased, with a large extent of variance. EOA increased along with an increase in mimic cardiac rate. It was a different response in terms of cardiac rate alteration for different types of mechanical prosthetic cardiac valves.Conclusion Mimic cardiac rate change affects hydrodynamics of mechanical prosthetic cardiac valves. Within physiological range, the hydrodynamic of prosthetic bileaflet valve is better than that of tilting disc valve.

  11. Steam and fuel oil supply and purge valve with cooling steam feature

    Buchanan, B.F.; Buchanan, J.R.


    This patent describes a steam and fuel oil supply and purge valve. It comprises a valve body defining steam and oil inlet ports, at least one discharge port, a steam purge passageway interconnecting the steam inlet and discharge ports, an oil supply passageway interconnecting the oil inlet and discharge ports, a cooling steam passageway interconnecting the steam inlet and discharge ports, a steam valve and actuator member movable between first, second, third, and fourth positions in the valve body and operable to open and close the steam purge and cooling steam passageways, a small metering passageway in the steam valve and actuator member which is so dimensioned and located as to open prior to full opening movement of the valve member and actuator relative to its seat, an oil valve member movable between first and second positions to open and close the oil supply passageway, biasing means urging the oil valve member toward its second and closed positions, the steam valve and actuator member in its first and second positions respectively closing and opening the steam purge passageway.

  12. AFM quantitative analysis and determination of shear angle of {259}f martensitic surface relief


    An attentive observation and quantitative analysis of {259}f martensitic surface relief in an Fe-23Ni-0.55C alloy are made by means of an atomic force microscope (AFM), and different martensitic variants' shear angles are determined in this paper. The experiments show that {259}f martensitic surface relief exhibits regular shape in many cases, which is in agreement with the prediction of invariant plane strain (IPS). Generally, {259}f martensitic surface relief appears to be "N"-shaped, but it is tent-shaped in the case of zigzag-shaped martensite. The compressed deformation of parent phase diminishes the surface relief in size but with little change of its relief angle. {259}f martensitic surface relief, large or small, has approximately the same relief angles, exhibiting a good "self-similar fractal". The determined values of different {259}f martensitic variants' shear angles are in fine agreement with the prediction of Wechsler-Liberman-Read (W-L-R) theory, with only a slight difference of less than 3.65°.

  13. Simpler valve for reciprocating engines

    Akkerman, J. W.


    Simpler design eliminating camshafts, cams, and mechanical springs should improve reliability of hydrazine powered reciprocating engines. Valve is expected to improve efficiency, and reduce weight of engines in range up to 50 horsepower.

  14. Titanium in engine valve systems

    Allison, J.E.; Sherman, A.M.; Bapna, M.R.


    Titanium alloys offer a unique combination of high strength-to-weight ratio, good corrosion resistance and favorable high temperature mechanical properties. Still, their relatively high cost has discouraged consideration for widespread use in automotive components. Recent demands for increased fuel economy have led to the consideration of these alloys for use as valve train materials where higher costs might be offset by improvements in performance and fuel economy. Lighter weight valve train components permit the use of lower spring loads, thus reducing friction and increasing fuel economy. Camshaft friction measurements made on a typical small displacement engine indicate that a two-to-four percent increase in fuel economy can be achieved. Valve train components are, however, subject to a severe operating environment, including elevated temperatures, sliding wear and high mechanical loads. This paper discusses the details of alloy and heat treatment selection for optimizing valve performance.

  15. Diseases of the Tricuspid Valve

    ... Kawasaki Disease Long Q-T Syndrome Marfan Syndrome Metabolic Syndrome Mitral Valve Prolapse Myocardial Bridge Myocarditis Obstructive Sleep Apnea Pericarditis Peripheral Vascular Disease Rheumatic Fever Sick Sinus Syndrome Silent Ischemia Stroke Sudden ...

  16. What Causes Heart Valve Disease?

    ... a heart attack or injury to the heart. Rheumatic Fever Untreated strep throat or other infections with strep bacteria that progress to rheumatic fever can cause heart valve disease. When the body ...




    Two patients with a quadricuspid aortic valve are described, one of them with concomitant juxtaposed coronary orifices facing the right hand facing sinus. The etiology and incidence of this congenital anomaly will be discussed.

  18. The spin-valve transistor

    Monsma, Douwe Johannes


    High density magnetic recording, magnetic random access memories, displacement and current detection, contactless switching and electronic compass applications all require magnetic field sensors with unprecedented sensitivity. The spin-valve effect (giant magnetoresistance) found in 1988 in magnetic

  19. 57. Aortic valve replacement with sutureless valve and mitral valve repair in patient with infected aortic homograft

    A. attia


    Full Text Available The approach of implanting aortic sutureless valve inside the calcific homograft is suitable in redo surgery especially if associated with mitral valve surgery. Aortic valve replacement in patients who have undergone previous aortic root replacement with an aortic homograft remains a technical challenge because of homograft degeneration and the need for a redo Bentall operation. We report a case of redo aortic valve replacement (valve in valve with a sutureless valve and mitral valve repair by miniband annuloplasty in a female patient aged 64 years old who underwent aortic valve replacement with homograft 14 years ago and presented by sever aortic valve regurge and sever mitral valve regurge because of infective endocarditis. This technique allows rapid aortic valve replacement in a heavily calcified aortic root. It also avoids aortic valve size affection after mitral valve repair by ordinary methods especially in patients with small aortic annulus. This technique is particularly suitable in redo procedures for homograft degeneration, it avoids performing a redo Bentall operation with its known problems as well as to avoid patient prosthesis mismatch.

  20. Shaded Relief of Minnesota Elevation - Color

    Minnesota Department of Natural Resources — This file is a product of a shaded relief process on the 30 meter resolution Digital Elevation Model data (dem30im3). This image was created using a custom AML...

  1. Lake Bathymetric DEM Shaded Relief Image

    Minnesota Department of Natural Resources — Geo-referenced, shaded relief image of lake bathymetry classified at 5-foot depth intervals. This dataset has a cell resolution of 5 meters (occasionally 10m) as...

  2. Non-Drug Pain Relief: Imagery

    PATIENT EDUCATION Non-Drug Pain Relief: Imagery Relaxation helps lessen tension. One way to help decrease pain is to use imagery. Imagery is using your imagination to create a ...

  3. U.S. Coastal Relief Model

    National Oceanic and Atmospheric Administration, Department of Commerce — NGDC's U.S. Coastal Relief Model (CRM) provides the first comprehensive view of the U.S. coastal zone integrating offshore bathymetry with land topography into a...

  4. Enveloping Relief Surfaces of Landslide Terrain


    Two relief surfaces that envelop the rock fall region in a part of Garhwal Himalayas around Chamoli have been identified. Relative relief and absolute relief have been analyzed and the enveloping surfaces recorded at two levels of relief in the landscape. All landslide activity lies within these surfaces. The lower enveloping surface (800 m) dips due south by 7-8 degrees, due to an elevation rise of 100 meters within 12 km from south to north, i.e., a gradient of 8 percent. The nature of the surface is smooth. The upper enveloping surface (> 2500 m) is almost parallel to the lower one but its surface is undulatory due to landslides and denudation. The area has been a seismically active region and has undergone seismic activity up until recently, as evidenced by the Chamoli earthquake of 29th March 1999. The effects of earthquakes are seen at higher levels in the form of landslide imprints on the terrain.

  5. U.S. Coastal Relief Model - Hawaii

    National Oceanic and Atmospheric Administration, Department of Commerce — NGDC's U.S. Coastal Relief Model (CRM) provides the first comprehensive view of the U.S. coastal zone integrating offshore bathymetry with land topography into a...

  6. Shaded Relief of Minnesota Elevation - Black & White

    Minnesota Department of Natural Resources — This file is a product of a shaded relief process on the 30 meter resolution Digital Elevation Model data (dem30im3). This image was created using a custom AML...

  7. Brain Circuits Encoding Reward from Pain Relief

    Navratilova, Edita; Atcherley, Christopher; Porreca, Frank


    Relief from pain in humans is rewarding and pleasurable. Primary rewards, or reward predictive cues, are encoded in brain reward/motivational circuits. While considerable advances have been made in our understanding of reward circuits underlying positive reinforcement, less is known about the circuits underlying the hedonic and reinforcing actions of pain relief. We review findings from electrophysiological, neuroimaging and behavioral studies supporting the concept that the rewarding effect of pain relief requires opioid signaling in the anterior cingulate cortex, activation of midbrain dopamine neurons and release of dopamine in the nucleus accumbens. Understanding of circuits that govern the reward of pain relief may allow the discovery of more effective and satisfying therapies for patients with acute and chronic pain. PMID:26603560

  8. Design of emergency relief system to flare; Projeto de sistemas de alivio de emergencia para tocha

    Britto, Joelson de Carvalho [PETROBRAS, Rio de Janeiro, RJ (Brazil)


    The relief system has for objective to protect the unit equipment and piping system for high pressures developed during eventual operational upset. As examples of operational upset could mention: human failure (operational mistake - example: inadvertent closure of a block valve), heat exchange tube rupture, utility failure (cooling water, electric power, steam, instrument air) and fire. The relieved products are piping to flare system in order to burn the waste gas. The burned or unburned relieved stream shall be dispersed in order to not to cause damages to the people and the environment. That system should operate automatically without the need of interference of the personnel of the operation. The system is basically constituted of Pressure Safety and Relief Valves (PSVs), piping net, gas-liquid separation vessel, separation vessel residual liquid pump (if necessary) and flare for burning waste gas without liquid. They are necessary also some utilities as fuel gas (to be used as purge gas by flare tip and as fuel gas by pilots in order to guarantee the continuous operation of the flare pilots), electric power, instrument/service air and compressed air or steam (if necessary) to improve the quality of the burns. (author)

  9. 46 CFR 151.20-5 - Cargo system valving requirements.


    ... °F (105 °F if tank is insulated) and which require greater protection due to their hazardous... valve; which may be part of the vessel's equipment or may be part of the shore facility and attached to... remote locations on the vessel; if means of fire protection is required by Table 151.05, the...

  10. Surgical outcomes in native valve infectious endocarditis: the experience of the Cardiovascular Surgery Department – Cluj-Napoca Heart Institute



    Background and aims The introduction of Duke’s criteria and the improvement of imaging methods has lead to an earlier and a more accurate diagnosis of infectious endocarditis (IE). The options for the best therapeutic approach and the timing of surgery are still a matter of debate and require a close colaboration between the cardiologist, the infectionist and the cardiac surgeon. Methods We undertook a retrospective, descriptive study, spanning over a period of five years (from January 1st, 2007 to December 31st, 2012), on 100 patients who underwent surgery for native valve infectious endocarditis in our unit. Results The patients’ age varied between 13 and 77 years (with a mean of 54 years), of which 85 were males (85%). The main microorganisms responsible for IE were: Streptococcus Spp. (21 cases – 21%), Staphylococcus Spp. (15 cases – 15%), and Enterococcus Spp. (9 cases – 9%). The potential source of infection was identified in 26 patients (26%), with most cases being in the dental area (16 cases – 16%). The lesions caused by IE were situated in the left heart in 96 patients (96%), mostly on the aortic valve (50 cases – 50%). In most cases (82%) we found preexisting endocardial lesions which predisposed to the development of IE, most of them being degenerative valvular lesions (38 cases – 38%). We performed the following surgical procedures: surgery on a single valve - aortic valve replacement (40 cases), mitral valve replacement (19 cases), mitral valve repair (1 case), surgery on more than one valve – mitral and aortic valve replacement (20 cases), aortic and tricuspid valve replacement (1 case), aortic valve replacement with a mechanical valve associated with mitral valve repair (5 cases), aortic valve replacement with a biological valve associated with mitral valve repair (2 cases), and mitral valve replacement with a mechanical valve combined with De Vega procedure on the tricuspid valve (1 case). In 5 patients (5%) the bacteriological

  11. Design of the Modular Pneumatic Valve Terminal

    Jakub E. TAKOSOGLU


    Full Text Available The paper presents design of the modular pneumatic valve terminal, which was made on the basis of the patent application No A1 402905 „A valve for controlling fluid power drives, specially for pneumatic actuators, and the control system for fluid power drives valves”. The authors describe a method of operation of the system with double-acting valve and 5/2 (five ways and two position valve. Functions of the valve, and an example of application of the valve terminal in the production process were presented. 3D solid models of all the components of the valve were made. The paper presents a complete 3D model of the valve in various configurations. Using CAD-embedded SOLIDWORKS Flow Simulation computational fluid dynamics CFD analysis was also carried out of compressed air flow in the ways of the valve elements

  12. TCT-670 Optimal Transcatheter Heart Valve Sizing in Aortic Valve in Valve Implantation: Insights from the Valve in Valve International Data (VIVID) Registry

    Alnasser, Sami; Cheema, Asim N; Horlick, Eric


    Background: Optimal transcatheter heart valve (THV) sizing is crucial to optimize procedural outcomes. Larger THV oversizing is shown to decrease paravalvular leakage post transcatheter aortic valve replacement but its role in Valve in Valve implantation (ViV) is not well established. Methods...... group received a larger THV (25.5± 1.4 mm vs. 23.3 ± 1.0 mm, pimplantation, the oversized group achieved a larger EOA (1.54±0.4cm2 vs. 1.37± 0.5cm2, p...V implantation was associated with favorable post-implant EOA and gradient but a higher risk of aortic insufficiency and THV re-intervention. Further exploration within various THV and surgical valve types at different degree of THV oversizing is planned....

  13. When does pleasure start after the end of pain? The time course of relief.

    Andreatta, Marta; Mühlberger, Andreas; Pauli, Paul


    Painful events are suggested to elicit two opponent responses: a negatively valenced and a positively valenced process triggered by their onset and termination, respectively. Consequently, stimuli (conditioned stimulus, CS) associated with pain onset (unconditioned stimulus, US) provoke defensive responses like startle potentiation, while stimuli associated with pain termination elicit appetitive responses like startle attenuation. Here we summarize four studies elucidating the time course of the relief following the termination of a painful US. In these studies, the timing of a relief-associated stimulus (reliefCS) presented after a painful US was varied from immediately (Study1), 3 seconds (Study4), or 6 seconds (Study2 and 3) after the US. Responses to these relief CSs were compared also with responses to a stimulus presented before the US (fearCS), and a third stimulus (safetyCS) that was never associated with the US. The synopsis of these studies reveals that the timing of the reliefCS is crucial to turn a defensive response into an appetitive response. Namely, the reliefCS immediately following the US-induced startle potentiation and negative valence (Study1); 3 seconds later, the startle response was slightly less potentiated and the ratings a little less negative (Study4); finally, the reliefCS presented 6 seconds after the US caused startle attenuation (Study2 and 3) and positively valenced ratings (Study3). In sum, the observed time course of relief closely follows the predictions of opponent process theory. This means that relief may be a reinforcer that elicits conditioned appetitive behavior, but its reinforcing properties strongly depend on its temporal relation to the aversive event.

  14. Echocardiographic Evaluation of Hemodynamic Changes in Left-Sided Heart Valves in Pregnant Women With Valvular Heart Disease.

    Samiei, Niloufar; Amirsardari, Mandana; Rezaei, Yousef; Parsaee, Mozhgan; Kashfi, Fahimeh; Hantoosh Zadeh, Sedigheh; Beikmohamadi, Somayeh; Fouladi, Masoumeh; Hosseini, Saeid; Peighambari, Mohammad Mehdi; Mohebbi, Ahmad


    Physiologic changes during pregnancy can deteriorate or improve patients' hemodynamic status in the setting of valvular heart disease. There are sparse data regarding the effect of pregnancy on valve hemodynamics in normal pregnant women with known valvular heart disease. In a prospective study from July 2014 to January 2016, a total of 52 normal pregnant women who had mitral stenosis, aortic stenosis, or a history of mitral valve or aortic valve replacements were assessed. All patients underwent echocardiographic examinations and hemodynamic parameters were measured for both the mitral valve and aortic valve at first, second, and third trimesters. The parameters included mean gradient, peak gradient, mean gradient/heart rate, peak gradient/heart rate, pressure halftime, dimensionless velocity index, and valve area. Although most hemodynamic parameters (i.e., mean gradient, peak gradient, mean gradient/heart rate, and peak gradient/heart rate) increased approximately 50% from first to second trimester and first to third trimester (p 0.05). The ratio of changes between trimesters for valve area and dimensionless velocity index were comparable. No clinical decompensations were observed except for 3 and 7 cases of deterioration to functional class II at second and third trimesters, respectively. In conclusion, during a full-term and uncomplicated pregnancy, mitral and aortic valve gradients increase without significant changes in valve area that are more marked between the second and first trimester than between the third and second trimester.

  15. Intermediate-term results of Medtronic freestyle valve for right ventricular outflow tract reconstruction in the Ross procedure.

    Bilal, Mehmet S; Aydemir, Numan A; Cine, Nihat; Turan, Tamer; Yildiz, Yahya; Yalcin, Yalim; Celebi, Ahmet


    The Ross procedure has become the first choice for aortic valve replacement in children and young adults at many institutions. Since 1997, a lack of availability of homograft valves in Turkey has prompted the use of alternative substitutes for right ventricular outflow tract (RVOT) reconstruction during the Ross procedure. Before April 2005, among 20 patients (age range: 14 months to 45 years) at the present authors' institution, the Ross procedure was performed in 14 and a Ross-Konno procedure in six. Sixteen patients underwent RVOT repair using alternative methods for homograft valve replacement. Fourteen patients received a Medtronic Freestyle valve and one patient a Medtronic Contegra bovine jugular vein conduit. An autologous RVOT repair was used in one patient. Ten of the Medtronic Freestyle valve patients were aged Medtronic Freestyle valve echocardiographic evaluations were conducted shortly after surgery and during follow up. There was no early mortality. One patient died from pneumonia after six months, and another (asymptomatic) patient died suddenly at 34 months after surgery. Before hospital discharge the mean peak pressure gradient across the Freestyle valve was 12.1 +/- 11.0 mmHg, and this increased to 24.1 +/- 20.0 mmHg after a mean follow up of 51.2 +/- 6.9 months (range: 6 to 101 months) (p Medtronic Freestyle valve, the present results show that the valve can be used with intermediate-term success in the Ross procedure - and even in children as an alternative - if homograft valves are not available.

  16. Development of an effective valve packing program

    Hart, K.A.


    Current data now shows that graphite valve packing installed within the guidance of a controlled program produces not only reliable stem sealing but predictable running loads. By utilizing recent technological developments in valve performance monitoring for both MOV`s and AOV`s, valve packing performance can be enhanced while reducing maintenance costs. Once known, values are established for acceptable valve packing loads, the measurement of actual valve running loads via the current MOV/AOV diagnostic techniques can provide indication of future valve stem sealing problems, improper valve packing installation or identify the opportunity for valve packing program improvements. At times the full benefit of these advances in material and predictive technology remain under utilized due to simple past misconceptions associated with valve packing. This paper will explore the basis for these misconceptions, provide general insight into the current understanding of valve packing and demonstrate how with this new understanding and current valve diagnostic equipment the key aspects required to develop an effective, quality valve packing program fit together. The cost and operational benefits provided by this approach can be significant impact by the: elimination of periodic valve repacking, reduction of maintenance costs, benefits of leak-free valve operation, justification for reduced Post Maintenance Test Requirements, reduced radiation exposure, improved plant appearance.

  17. Laparoscopic Adhesiolysis and Relief of Chronic Pelvic Pain

    Nezhat, Farr R.; Crystal, Ruth Ann; Nezhat, Ceana H.


    Objective: To evaluate the short- and long-term results of laparoscopic enterolysis in patients with chronic pelvic pain following hysterectomy. Methods: Forty-eight patients were evaluated at time intervals from 2 weeks to 5 years after laparoscopic enterolysis. Patients were asked to rate postoperative relief of their pelvic pain as complete/near complete relief (80-100% pain relief), significant relief (50-80% pain relief), or less than 50% or no pain relief. Results: We found that after 2 to 8 weeks, 39% of patients reported complete/near complete pain relief, 33% reported significant pain relief, and 28% reported less than 50% or no pain relief. Six months to one year postlaparoscopy, 49% of patients reported complete/near complete pain relief, 15% reported significant pain relief, and 36% reported less than 50% or no pain relief. Two to five years after laparoscopic enterolysis, 37% of patients reported complete/near complete pain relief, 30% reported significant pain relief, and 33% reported less than 50% or no pain relief. Some patients required between 1 and 3 subsequent laparoscopic adhesiolysis. A total of 3 enterotomies and 2 cystotomies occurred, all of which were repaired laparoscopically. Conclusion: We conclude that laparoscopic enterolysis may offer significant long-term relief of chronic pelvic pain in some patients. PMID:11051185

  18. 48 CFR 252.229-7001 - Tax relief.


    ... 48 Federal Acquisition Regulations System 3 2010-10-01 2010-10-01 false Tax relief. 252.229-7001... Clauses 252.229-7001 Tax relief. As prescribed in 229.402-70(a), use the following clause: Tax Relief (JUN... or components intended to be imported in order to ensure that relief from import duties is obtained...

  19. 7 CFR 635.5 - Forms of relief.


    ... 7 Agriculture 6 2010-01-01 2010-01-01 false Forms of relief. 635.5 Section 635.5 Agriculture... AGRICULTURE LONG TERM CONTRACTING EQUITABLE RELIEF FROM INELIGIBILITY § 635.5 Forms of relief. (a) The Chief... land covered by the program; and (5) Receive such other equitable relief as determined to be...

  20. 37 CFR 41.120 - Notice of basis for relief.


    ... 37 Patents, Trademarks, and Copyrights 1 2010-07-01 2010-07-01 false Notice of basis for relief... Notice of basis for relief. (a) The Board may require a party to provide a notice stating the relief it requests and the basis for its entitlement to relief. The Board may provide for the notice to be maintained...

  1. 19 CFR 210.52 - Motions for temporary relief.


    ... 19 Customs Duties 3 2010-04-01 2010-04-01 false Motions for temporary relief. 210.52 Section 210... IMPORT TRADE ADJUDICATION AND ENFORCEMENT Temporary Relief § 210.52 Motions for temporary relief. Requests for temporary relief under section 337 (e) or (f) of the Tariff Act of 1930 shall be made through...

  2. 43 CFR 4.1367 - Request for temporary relief.


    ... 43 Public Lands: Interior 1 2010-10-01 2010-10-01 false Request for temporary relief. 4.1367... temporary relief. (a) Where review is requested pursuant to § 4.1362, any party may file a request for temporary relief at any time prior to a decision by an Administrative Law Judge, so long as the relief...

  3. 7 CFR 718.305 - Forms of relief.


    ... 7 Agriculture 7 2010-01-01 2010-01-01 false Forms of relief. 718.305 Section 718.305 Agriculture... Equitable Relief From Ineligibility § 718.305 Forms of relief. (a) The Administrator of FSA, Executive Vice... all or part of the land covered by the program; and (5) Receive such other equitable relief as...

  4. Surgical treatment of aortic valve endocarditis: a 26-year experience

    Taylan Adademir


    Full Text Available Objective: We have retrospectively analyzed the results of the operations made for aortic valve endocarditis in a single center in 26 years. Methods: From June 1985 to January 2011, 174 patients were operated for aortic valve endocarditis. One hundred and thirty-eight (79.3% patients were male and the mean age was 39.3±14.4 (9-77 years. Twenty-seven (15.5% patients had prosthetic valve endocarditis. The mean duration of follow-up was 7.3±4.2 years (0.1-18.2 adding up to a total of 1030.8 patient/years. Results: Two hundred and eighty-two procedures were performed. The most frequently performed procedure was aortic valve replacement with mechanical prosthesis (81.6%. In-hospital mortality occurred in 27 (15.5% cases. Postoperatively, 25 (14.4% patients had low cardiac output and 17 (9.8% heart block. The actuarial survival rates for 10 and 15 years were 74.6±3.7% and 61.1±10.3%, respectively. In-hospital mortality was found to be associated with female gender, emergency operation, postoperative renal failure and low cardiac output. The long term mortality was significantly associated with mitral valve involvement. Male gender was found to be a significant risk factor for recurrence in the follow-up. Conclusion: Surgery for aortic valve endocarditis has significant mortality. Emergency operation, female gender, postoperative renal failure and low cardiac output are significant risk factors. Risk for recurrence and need for reoperation is low.

  5. Anterior urethral valves: not such a benign condition…

    Omar eCruz-Diaz


    Full Text Available Purpose: Anterior urethral valves (AUV is an unusual cause of congenital obstruction of the male urethra, being 15 to 30 times less common than posterior urethral valves (PUV. It has been suggested that patients with congenital anterior urethral obstruction have a better prognosis than those with PUV.The long term prognosis of anterior urethral valves is not clear in the literature. In this report we describe our experience and long-term follow up of patients with AUV.Materials and methods: We retrospectively identified 13 patients who presented with the diagnosis of AUV in our institutions between 1994 and 2012. From the 11 patients included, we evaluated the gestational age, ultrasound and voiding cystourethrogram findings, age upon valve ablation, micturition pattern, creatinine and clinical follow up.Results: Between 1994 and 2012 we evaluated 150 patients with the diagnosis of urethral valves, where 11 patients (7.3% had AUV and an adequate follow up. Mean follow up is 6.3 years. 5 patients (45.4% had pre-natal diagnosis of AUV. The most common prenatal ultrasonographic finding was bilateral hydronephrosis and distended bladder.The mean gestational age was 37.6 weeks. Postnatally, 90% had trabeculated bladder, 80% hydronephrosis and 40% renal dysplasia. The most common clinical presentation was urinary tract infection in 5 patients (45.4%.7 patients (63.6% had primary transurethral valve resection or laser ablation and 3 patients (27.2% had primary vesicostomies. One boy (9.1% had urethrostomy with urethral diverticulum excision. 2 patients (18.2% developed end-stage renal disease (ESRD.Conclusions: Early urinary tract obstruction resulted in ESRD in 18% of our patient population. In our series, the complication rate and the evolution to renal failure are high and similar to patients with PUV. In patients with AUV we recommend long-term follow up and close evaluation of patient’s bladder and renal function.

  6. Gas flow across a wet screen - Analogy to a relief valve with hysteresis

    Nachman, A.; Dodge, F. T.


    The flow of gas through a wet fine-mesh screen is analyzed in terms of the capillary forces of the liquid wetting the screen and the pressure difference across the screen thickness driving the gas flow. Several different types of time-dependent flow are shown to be possible. The most interesting type is one in which the pressure difference opens small channels in the liquid, which are then closed rapidly by the wetting action of the liquid. The opening and closing exhibit hysteresis, and the flow is highly oscillatory.

  7. 49 CFR 178.337-9 - Pressure relief devices, piping, valves, hoses, and fittings.


    ... must not be capable of causing any adverse chemical reaction with the cargo tank lading in the event of... heavier, except for sacrificial devices. Malleable metal, stainless steel, or ductile iron must be used in.... Stainless steel may be used for internal components such as shutoff discs and springs except...

  8. Evaluation of an International Disaster Relief Team After Participation in an ASEAN Regional Forum Disaster Relief Exercise.

    Lee, Jeong Il; Lee, Kang Hyun; Kim, Oh Hyun; Cha, Yong Sung; Hwang, Sung Oh; Kim, Hyun; Cha, Kyung Chul


    Devastating disasters around the world directly contribute to significant increases in human mortality and economic costs. The objective of this study was to examine the current state of the Korea Disaster Relief Team that participated in an international training module. The whole training period was videotaped in order to observe and evaluate the respondents. The survey was carried out after completion of the 3-day training, and the scores were reported by use of a 5-point Likert scale. A total of 43 respondents were interviewed for the survey, and the results showed that the overall preparedness score for international disasters was 3.4±1.6 (mean±SD). The awareness of the Incident Command System for international disasters was shown to be low (3.5±1.1). Higher scores were given to personnel who took on leadership roles in the team and who answered "I knew my duty" (4.4±0.6) in the survey, as well as to the training participants who answered "I clearly knew my duty" (4.5±0.5). The preparedness level of the Korea Disaster Relief Team was shown to be insufficient, whereas understanding of the roles of leaders and training participants in the rescue team was found to be high. It is assumed that the preparedness level for disaster relief must be improved through continued training. (Disaster Med Public Health Preparedness. 2016;1-5).

  9. Analysis of Complex Valve and Feed Systems

    Ahuja, Vineet; Hosangadi, Ashvin; Shipman, Jeremy; Cavallo, Peter; Dash, Sanford


    A numerical framework for analysis of complex valve systems supports testing of propulsive systems by simulating key valve and control system components in the test loop. In particular, it is designed to enhance the analysis capability in terms of identifying system transients and quantifying the valve response to these transients. This system has analysis capability for simulating valve motion in complex systems operating in diverse flow regimes ranging from compressible gases to cryogenic liquids. A key feature is the hybrid, unstructured framework with sub-models for grid movement and phase change including cryogenic cavitations. The multi-element unstructured framework offers improved predictions of valve performance characteristics under steady conditions for structurally complex valves such as pressure regulator valve. Unsteady simulations of valve motion using this computational approach have been carried out for various valves in operation at Stennis Space Center such as the split-body valve and the 10-in. (approx.25.4-cm) LOX (liquid oxygen) valve and the 4-in. (approx.10 cm) Y-pattern valve (liquid nitrogen). Such simulations make use of variable grid topologies, thereby permitting solution accuracy and resolving important flow physics in the seat region of the moving valve. An advantage to this software includes possible reduction in testing costs incurred due to disruptions relating to unexpected flow transients or functioning of valve/flow control systems. Prediction of the flow anomalies leading to system vibrations, flow resonance, and valve stall can help in valve scheduling and significantly reduce the need for activation tests. This framework has been evaluated for its ability to predict performance metrics like flow coefficient for cavitating venturis and valve coefficient curves, and could be a valuable tool in predicting and understanding anomalous behavior of system components at rocket propulsion testing and design sites.

  10. Repeated thermo-sterilisation further affects the reliability of positive end-expiratory pressure valves.

    Hartung, Julia Christine; Schmölzer, Georg; Schmalisch, Gerd; Roehr, Charles Christoph


    Positive end-expiratory pressure (PEEP) valves are used together with self-inflating bags (SIB) to provide a preset PEEP during manual ventilation. It has recently been shown that these valves deliver highly variable levels of PEEP. We hypothesised that material fatigue due to repeated thermo-sterilisation (TS) may contribute to varying reliability of PEEP valves. In a laboratory study 10 new PEEP valves were tested before and after 10, 20 and 30 cycles of routine TS (7 min at 134°C) by using a neonatal lung model (compliance 0.2 mL/kPa). Settings were positive inflation pressure = 20 and 40 cm H(2)O, PEEP = 5 and 10 cm H(2)O, respiratory rate = 40 and 60/min, flow = 8l/min. PEEP was recorded using a respiratory function monitor. Before TS, a mean (standard deviation) PEEP of 4.0 (0.9) and 7.7 (1.0) cm H(2)O was delivered by the 10 valves when the PEEP was set to 5 and 10 cm H(2)O, respectively. One new valve only delivered 2.0 (0.0) and 5.0 (0.0) cm H(2)O when the PEEP was adjusted to 5 and 10 cm H(2)O, respectively. Four of the 10 investigated valves showed significant variations in PEEP (coefficient of variation >10%) throughout the autoclaving process. One valve completely lost its function after the 20th TS. Common defects were tears in the softer materials or displacement of the rubber seal. Six of the 10 valves continued to provide PEEP in spite of repeated TS. The reliability of PEEP valves is affected by repeated TS. Multi-use PEEP valves should be tested for reliable PEEP provision following TS. © 2013 The Authors. Journal of Paediatrics and Child Health © 2013 Paediatrics and Child Health Division (Royal Australasian College of Physicians).

  11. Cutting precision in a novel aortic valve resection tool. Research in progress.

    Wendt, Daniel; Stühle, Sebastian; Wendt, Hermann; Thielmann, Matthias; Kipfmüller, Brigitte; Hauck, Florian; Vogel, Bernd; Jakob, Heinz


    We recently demonstrated the first in-vitro cutting results of a minimal-invasive aortic valve resection tool. The current study was designed to assess the cutting accuracy of this new device improved by the implementation of a linear motor-based propulsion unit. Native aortic valves of isolated swine hearts (valve diameter 17.8+/-0.9 mm, mean+/-S.D.) were artificially stenosed and calcified (n=7). Subsequently, valves were resected by the use of a new aortic valve resection tool. The cutting process was performed by fitting the instrument with foldable Nitinol cutting blades (diameter 15 mm) and two software-operated linear motors combined with separated manual rotation. Aortic valve area was measured pre- and postprocedure by software-guided binary area calculation. Aortic valve residue has been determined and the grade of accuracy has been assessed via calculating the average midpoint of the neoannulus. Furthermore, radial deviation of concentricity was calculated and cutting time was measured. Aortic valve resection was successful in all cases and nearly all leaflets (2.5+/-0.4) with a weight of 0.22+/-0.12 g were cut. Aortic valve area increased significantly (0.3+/-0.1 cm(2) vs. 1.1+/-0.2 cm(2), Pvalve by the aortic valve resection tool. Nearly all leaflets were cut and a small rim was left within the annulus, hence providing an ideal 'landing zone' for the new prosthesis. Nevertheless, the aortic valve resection tool should be enhanced by adding a centering mechanism, thus achieving a more precise cutting process in order to avoid secondary damage.

  12. Titanium in Engine Valve Systems

    Allison, J. E.; Sherman, A. M.; Bapna, M. R.


    Titanium alloys offer a unique combination of high strength-to-weight ratio, good corrosion resistance and favorable high temperature mechanical properties. Still, their relatively high cost has discouraged consideration for widespread use in automotive components. Recent demands for increased fuel economy have led to the consideration of these alloys for use as valve train materials where higher costs might be offset by improvements in performance and fuel economy. Lighter weight valve train components permit the use of lower spring loads, thus reducing friction and increasing fuel economy. Camshaft friction measurements made on a typical small displacement engine indicate that a twoto-four percent increase in fuel economy can be achieved. Valve train components are, however, subject to a severe operating environment, including elevated temperatures, sliding wear and high mechanical loads. This paper discusses the details of alloy and heat treatment selection for optimizing valve performance. When properly manufactured, titanium valves have been shown to withstand very stringent durability testing, indicating the technical feasibility of this approach to fuel economy improvement.

  13. Large Scale Magnetostrictive Valve Actuator

    Richard, James A.; Holleman, Elizabeth; Eddleman, David


    Marshall Space Flight Center's Valves, Actuators and Ducts Design and Development Branch developed a large scale magnetostrictive valve actuator. The potential advantages of this technology are faster, more efficient valve actuators that consume less power and provide precise position control and deliver higher flow rates than conventional solenoid valves. Magnetostrictive materials change dimensions when a magnetic field is applied; this property is referred to as magnetostriction. Magnetostriction is caused by the alignment of the magnetic domains in the material s crystalline structure and the applied magnetic field lines. Typically, the material changes shape by elongating in the axial direction and constricting in the radial direction, resulting in no net change in volume. All hardware and testing is complete. This paper will discuss: the potential applications of the technology; overview of the as built actuator design; discuss problems that were uncovered during the development testing; review test data and evaluate weaknesses of the design; and discuss areas for improvement for future work. This actuator holds promises of a low power, high load, proportionally controlled actuator for valves requiring 440 to 1500 newtons load.

  14. 49 CFR 179.400-19 - Valves and gages.


    ... 49 Transportation 2 2010-10-01 2010-10-01 false Valves and gages. 179.400-19 Section 179.400-19...-19 Valves and gages. (a) Valves. Manually operated shut-off valves and control valves must be... liquid flow rates. All valves must be made from approved materials compatible with the lading and...

  15. Obstructive Thebesian valve: anatomical study and implications for invasive cardiologic procedures.

    Ghosh, Sanjib Kumar; Raheja, Shashi; Tuli, Anita


    Thebesian valve is the embryological remnant of the right sinoatrial valve, guarding the coronary sinus (CS) ostium. Advanced invasive and interventional cardiac diagnostic and management tools involve cannulation of the CS ostium. The presence of obstructive Thebesian valves has been reported to lead to unsuccessful cannulation of the CS. We studied the morphology of the Thebesian valve and CS ostium to assess the possible impact of these structures on invasive cardiological procedures. One hundred fifty randomly selected human cadaveric heart specimens fixed in 10% formalin were dissected in the customary routine manner. The Thebesian valves were classified according to their shape as semilunar/fenestrated/biconcave band like and according to their composition as membranous/fibromuscular/fibrous/muscular, and the extent to which the valve covered the CS ostium was also noted. An obstructive Thebesian valve that could interfere with the cannulation of the CS was defined as non-fenestrated (semilunar/biconcave band like) and non-membranous (fibromuscular/fibrous/muscular) valves covering >75% of the CS ostium. Thebesian valves were present in 118 (79%) heart specimens, of which 27 (18%) met the criteria of being obstructive. Semilunar was the most common type of Thebesian valve in terms of shape and was observed in 65 (65/118; 55%) hearts. This type was associated with the least mean craniocaudal (7.9±0.6 mm) and mean transverse (6.25±0.6 mm) diameters of the CS ostium. The mean craniocaudal diameter of the CS ostium (9.4±2.1 mm) was significantly larger (p=0.004) than the mean transverse diameter (7.15±1.5 mm) in specimens with Thebesian valves, and the cranial margin of the CS ostium was free from any attachment of the Thebesian valve in all the types observed (in terms of shape). Hence, attempts to direct the tip of the catheter toward the cranial margin of the CS ostium under direct vision may lead to successful cannulation of the same when conventional

  16. The nordic aortic valve intervention (NOTION) trial comparing transcatheter versus surgical valve implantation

    Thyregod, Hans Gustav; Søndergaard, Lars; Ihlemann, Nikolaj;


    Degenerative aortic valve (AV) stenosis is the most prevalent heart valve disease in the western world. Surgical aortic valve replacement (SAVR) has until recently been the standard of treatment for patients with severe AV stenosis. Whether transcatheter aortic valve implantation (TAVI) can...

  17. Aortic valve replacement with the Nicks annulus enlargement procedure 12 years after mitral valve replacement.

    Kazama, S; Kurata, A; Yamashita, Y


    An aortic valve replacement was successfully performed employing the Nicks annulus enlargement procedure in a case of aortic valve stenosis with small annulus 12 years after mitral valve replacement. Previous mitral valve replacement does not preclude feasibility of the Nicks procedure.

  18. Sex-Related Discordance Between Aortic Valve Calcification and Hemodynamic Severity of Aortic Stenosis: Is Valvular Fibrosis the Explanation?

    Simard, Louis; Côté, Nancy; Dagenais, François; Mathieu, Patrick; Couture, Christian; Trahan, Sylvain; Bossé, Yohan; Mohammadi, Siamak; Pagé, Sylvain; Joubert, Philippe; Clavel, Marie-Annick


    Calcific aortic stenosis (AS) is characterized by calcium deposition in valve leaflets. However, women present lower aortic valve calcification loads than men for the same AS hemodynamic severity. We, thus, aimed to assess sex differences in aortic valve fibrocalcific remodeling. One hundred and twenty-five patients underwent Doppler echocardiography and multidetector computed tomography within 3 months before aortic valve replacement. Explanted stenotic tricuspid aortic valves were weighed, and fibrosis degree was determined. Sixty-four men and 39 women were frequency matched for age, body mass index, hypertension, renal disease, diabetes mellitus, and AS severity. Mean age (75±9 years), mean gradient (41±18 mm Hg), and indexed aortic valve area (0.41±0.12 cm(2)/m(2)) were similar between men and women (all P≥0.18). Median aortic valve calcification (1973 [1124-3490] Agatston units) and mean valve weight (2.36±0.99 g) were lower in women compared with men (both Pvalve calcification density correlated better with valve weight in men (r(2)=0.57; Pvalve calcification density, and aortic annulus diameter, female sex was an independent risk factor for higher fibrosis score in AS valves (P=0.003). Picrosirius red staining of explanted valves showed greater amount of collagen fibers (P=0.01), and Masson trichrome staining revealed a greater proportion of dense connective tissue (P=0.02) in women compared with men. In this series of patients with tricuspid aortic valve and similar AS severity, women have less valvular calcification but more fibrosis compared with men. These findings suggest that the pathophysiology of AS and thus potential targets for drug development may be different according to sex. © 2016 American Heart Association, Inc.

  19. Transapical transcatheter valve-in-valve replacement for deteriorated mitral valve bioprosthesis without radio-opaque indicators: the "invisible" mitral valve bioprosthesis.

    Rossi, Marco Luciano; Barbaro, Cristina; Pagnotta, Paolo; Cappai, Antioco; Ornaghi, Diego; Belli, Guido; Presbitero, Patrizia


    In view of the high number of bioprosthetic valves implanted during the past 30 years, an increasing number of patients are coming to medical attention because of degenerated bioprostheses. Transcatheter aortic valve-in-valve implantation has been described as a less invasive alternative to re-operation to treat severe structural valve deterioration. As far as degenerated mitral valve bioprostheses are concerned, transcatheter transapical mitral valve-in-valve replacement (TMVR) has been less commonly performed, but may also become a viable alternative to re-do replacement surgery. We describe treatment of a degenerated bioprosthetic mitral valve, characterised by complete absence of any radio-opaque landmarks making the TMVR procedure very challenging.

  20. Percutaneous heart valves; past, present and future.

    Rozeik, M M; Wheatley, D J; Gourlay, T


    Percutaneous heart valves provide a promising future for patients refused surgery on the grounds of significant technical challenges or high risk for complications. Since the first human intervention more than 10 years ago, over 50 different types of valves have been developed. The CoreValve and Edwards SAPIEN valves have both experienced clinical trials and the latter has gained FDA approval for implantation in patients considered inoperable. Current complications, such as major vascular bleeding and stroke, prevent these valves from being commonly deployed in patients considered operable in conventional surgery. This review focuses on the past and present achievements of these valves and highlights the design considerations required to progress development further. It is envisaged that, with continued improvement in valve design and with increased clinical and engineering experience, percutaneous heart valve replacement may one day be a viable option for lower-risk operable patients.

  1. Initial Surgical Experience with Aortic Valve Repair: Clinical and Echocardiographic Results

    da Costa, Francisco Diniz Affonso; Colatusso, Daniele de Fátima Fornazari; da Costa, Ana Claudia Brenner Affonso; Balbi Filho, Eduardo Mendel; Cavicchioli, Vinicius Nesi; Lopes, Sergio Augusto Veiga; Ferreira, Andrea Dumsch de Aragon; Collatusso, Claudinei


    Introduction Due to late complications associated with the use of conventional prosthetic heart valves, several centers have advocated aortic valve repair and/or valve sparing aortic root replacement for patients with aortic valve insufficiency, in order to enhance late survival and minimize adverse postoperative events. Methods From March/2012 thru March 2015, 37 patients consecutively underwent conservative operations of the aortic valve and/or aortic root. Mean age was 48±16 years and 81% were males. The aortic valve was bicuspid in 54% and tricuspid in the remaining. All were operated with the aid of intraoperative transesophageal echocardiography. Surgical techniques consisted of replacing the aortic root with a Dacron graft whenever it was dilated or aneurysmatic, using either the remodeling or the reimplantation technique, besides correcting leaflet prolapse when present. Patients were sequentially evaluated with clinical and echocardiographic studies and mean follow-up time was 16±5 months. Results Thirty-day mortality was 2.7%. In addition there were two late deaths, with late survival being 85% (CI 95% - 68%-95%) at two years. Two patients were reoperated due to primary structural valve failure. Freedom from reoperation or from primary structural valve failure was 90% (CI 95% - 66%-97%) and 91% (CI 95% - 69%-97%) at 2 years, respectively. During clinical follow-up up to 3 years, there were no cases of thromboembolism, hemorrhage or endocarditis. Conclusions Although this represents an initial series, these data demonstrates that aortic valve repair and/or valve sparing aortic root surgery can be performed with satisfactory immediate and short-term results. PMID:27556321

  2. Transcatheter aortic valve implantation of the direct flow medical aortic valve with minimal or no contrast

    Latib, Azeem, E-mail: [Interventional Cardiology Unit, San Raffaele Scientific Institute and EMO-GVM Centro Cuore Columbus, Milan (Italy); Maisano, Francesco; Colombo, Antonio [Interventional Cardiology Unit, San Raffaele Scientific Institute and EMO-GVM Centro Cuore Columbus, Milan (Italy); Klugmann, Silvio [Azienda Ospedaliera Niguarda Ca Granda, Piazza Ospedale Maggiore 3, Milan (Italy); Low, Reginald; Smith, Thomas [University of California Davis, Davis, CA 95616 (United States); Davidson, Charles [Northwestern Memorial Hospital, Chicago, IL 60611 (United States); Harreld, John H. [Clinical Imaging Analytics, Guerneville, CA (United States); Bruschi, Giuseppe; DeMarco, Federico [Azienda Ospedaliera Niguarda Ca Granda, Piazza Ospedale Maggiore 3, Milan (Italy)


    The 18F Direct Flow Medical (DFM) THV has conformable sealing rings, which minimizes aortic regurgitation and permits full hemodynamic assessment of valve performance prior to permanent implantation. During the DISCOVER trial, three patients who were at risk for receiving contrast media, two due to severe CKD and one due to a recent hyperthyroid reaction to contrast, underwent DFM implantation under fluoroscopic and transesophageal guidance without aortography during either positioning or to confirm the final position. Valve positioning was based on the optimal angiographic projection as calculated by the pre-procedural multislice CT scan. Precise optimization of valve position was performed to minimize transvalve gradient and aortic regurgitation. Prior to final implantation, transvalve hemodynamics were assessed invasively and by TEE. The post-procedure mean gradients were 7, 10, 11 mm Hg. The final AVA by echo was 1.70, 1.40 and 1.68 cm{sup 2}. Total aortic regurgitation post-procedure was none or trace in all three patients. Total positioning and assessment of valve performance time was 4, 6, and 12 minutes. Contrast was only used to confirm successful percutaneous closure of the femoral access site. The total contrast dose was 5, 8, 12 cc. Baseline eGFR and creatinine was 28, 22, 74 mL/min/1.73 m{sup 2} and 2.35, 2.98, and 1.03 mg/dL, respectively. Renal function was unchanged post-procedure: eGFR = 25, 35, and 96 mL/min/1.73 m{sup 2} and creatinine = 2.58, 1.99, and 1.03 mg/dL, respectively. In conclusion, the DFM THV provides the ability to perform TAVI with minimal or no contrast. The precise and predictable implantation technique can be performed with fluoro and echo guidance.

  3. Pain relief as an opponent process: a psychophysical investigation.

    Leknes, Siri; Brooks, Jonathan C W; Wiech, Katja; Tracey, Irene


    Relief from pain in humans is frequently measured by computing the reduction on an 11-point pain intensity scale. However, this definition of relief may be insufficient to capture the utility of pain relief for the individual. Based on pain literature and evidence from studies examining relief and reward, it is clear that pain relief is a broad concept comprising several factors, only one of which is pain intensity reduction. According to opponent process theory, all sensations consist of a primary process and a slow 'opponent process' of opposite valence, the purpose of which is to reduce the deviation from homeostatic balance. Here, opponent process theory provided a framework to explore the interaction between pain, relief and reward. We devised three psychophysical studies examining the temporal (Experiment I) and magnitude (Experiments I and II) relationships between pain severity and its subsequent relief. In Experiment III, we further manipulated the magnitude and pleasantness of relief experienced by applying innocuous cooling following noxious heat stimulation of capsaicin-sensitized skin. Results confirmed predictions from opponent process theory and showed that pain intensity reduction was significantly stronger than relief intensity ratings. Furthermore, continuous relief ratings appeared to reflect the speed of pain intensity reduction. Varying pain intensity parametrically confirmed that relief increases with pain intensity. That innocuous cooling following primary hyperalgesia intervention significantly increased the intensity, pleasantness and duration of relief provides further evidence that pain relief encapsulates more than a reduction in pain intensity. Importantly, the high relief pleasantness ratings confirmed the hypothesized link between relief and reward.

  4. 14 CFR 25.1189 - Shutoff means.


    ... powerplant or engine mount structural failure. (h) Each shutoff valve must have a means to relieve excessive...) Each engine installation and each fire zone specified in § 25.1181(a)(4) and (5) must have a means to... required for— (1) Lines, fittings, and components forming an integral part of an engine; and (2)...

  5. 14 CFR 23.1189 - Shutoff means.


    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Shutoff means. 23.1189 Section 23.1189... § 23.1189 Shutoff means. (a) For each multiengine airplane the following apply: (1) Each engine... shutoff valve for any engine may not make any fuel unavailable to the remaining engines that would...

  6. 14 CFR 29.1189 - Shutoff means.


    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Shutoff means. 29.1189 Section 29.1189... STANDARDS: TRANSPORT CATEGORY ROTORCRAFT Powerplant Powerplant Fire Protection § 29.1189 Shutoff means. (a... displacement. (b) The closing of any fuel shutoff valve for any engine may not make fuel unavailable to...

  7. Propellant isolation shutoff valve program

    Merritt, F. L.


    An analysis and design effort directed to advancing the state-of-the-art of space storable isolation valves for control of flow of the propellants liquid fluorine/hydrazine and Flox/monomethylhydrazine is discussed. Emphasis is on achieving zero liquid leakage and capability of withstanding missions up to 10 years in interplanetary space. Included is a study of all-metal poppet sealing theory, an evaluation of candidate seal configurations, a valve actuator trade-off study and design description of a pneumo-thermally actuated soft metal poppet seal valve. The concepts and analysis leading to the soft seal approach are documented. A theoretical evaluation of seal leakage versus seal loading, related finishes and yield strengths of various materials is provided. Application of a confined soft aluminum seal loaded to 2 to 3 times yield strength is recommended. Use of either an electro-mechanical or pneumatic actuator appears to be feasible for the application.

  8. Novel Active Combustion Control Valve

    Caspermeyer, Matt


    This project presents an innovative solution for active combustion control. Relative to the state of the art, this concept provides frequency modulation (greater than 1,000 Hz) in combination with high-amplitude modulation (in excess of 30 percent flow) and can be adapted to a large range of fuel injector sizes. Existing valves often have low flow modulation strength. To achieve higher flow modulation requires excessively large valves or too much electrical power to be practical. This active combustion control valve (ACCV) has high-frequency and -amplitude modulation, consumes low electrical power, is closely coupled with the fuel injector for modulation strength, and is practical in size and weight. By mitigating combustion instabilities at higher frequencies than have been previously achieved (approximately 1,000 Hz), this new technology enables gas turbines to run at operating points that produce lower emissions and higher performance.



    A novel pilot stage valve called simplified 2D valve, which utilizes both rotary and linear motions of a single spool, is presented.The rotary motion of the spool incorporating hydraulic resistance bridge, formed by a damper groove and a crescent overlap opening, is utilized as pilot to actuate linear motion of the spool.A criterion for stability is derived from the linear analysis of the valve.Special experiments are designed to acquire the mechanical stiffness, the pilot leakage and the step response.It is shown that the sectional size of the spiral groove affects the dynamic response and the stiffness contradictorily and is also very sensitive to the pilot leakage.Therefore, it is necessary to establish a balance between the static and dynamic characteristics in deciding the structural parameters.Nevertheless, it is possible to sustain the dynamic response at a fairly high level, while keeping the leakage of the pilot stage at an acceptable level.

  10. Fifteen-year experience with the Bicarbon heart valve prosthesis in a single center.

    Misawa, Yoshio; Muraoka, Arata; Ohki, Shin-ichi; Aizawa, Kei; Kawahito, Koji; Saito, Tsutomu; Sato, Hirotaka; Takazawa, Ippei; Kurumisawa, Soki; Akutsu, Hirohiko; Sugaya, Akira


    The purpose of this study was to evaluate retrospectively the clinical performance of the Bicarbon valve (Sorin Biomedica Cardio, Saluggia, Italy) implanted at our center in Japan. Between January 1997 and December 2011, 415 patients in our institution were implanted with the Bicarbon valve. Nine of these recipients were excluded from the study because they had already undergone valve implantation and received a Bicarbon valve in a different position. The remaining patients were analyzed for evaluation of the postoperative clinical outcomes. Of the 406 patients (mean age 60.2 ± 11.7 years), 179 underwent aortic valve replacement (AVR), 149 mitral valve replacement (MVR), and 78 both aortic and mitral valve replacement (DVR). There were 10 early deaths (2.5 %: 4 in the AVR group and 6 in the MVR group). Three hundred eighty-nine patients were followed up (95.8 % completeness of follow-up) with a mean follow-up of 6.6 ± 4.2 years overall (AVR 6.8 ± 4.2, MVR, 6.7 ± 4.4, and DVR 5.7 ± 3.4 years) and a cumulative follow-up of 2661 patient-years (1214, 1001, and 446 patient-years for AVR, MVR, and DVR, respectively). Ninety-nine patients died (3.7 % per patient-year: 22 valve-related and 77 valve-unrelated deaths). Survival at 10 years was 74.1 ± 4.0 % in the AVR group, 73.7 ± 4.2 % in the MVR group, and 61.0 ± 7.9 % in the DVR group. The linearized incidence of thromboembolic complications, bleeding complications, prosthetic valve endocarditis, paravalvular leaks, and sudden death in all patients was 0.5 %, 0.5 %, 0.2 %, 0.2 %, and 0.4 % per patient-year, respectively. The incidence of valve-related complications and reoperation was 1.6 % and 0.4 %, respectively. No other valve-related complications were observed. The Bicarbon prosthetic heart valve has shown excellent clinical results and is associated with a low incidence of valve-related complications.

  11. Transapical Mitral Valve-in-Valve Replacement in Patient With Previous Complex Sternal Reconstruction.

    Hynes, Conor F; Fatemi, Omid; Sharma, Aditya C; Nagy, Christian D; Trachiotis, Gregory D


    We present a complex case of a transapical redo mitral valve-in-valve replacement. Repeat mitral valve replacement was indicated for severe symptomatic bioprosthetic stenosis. In addition to the patient's numerous comorbidities that included diabetes, hepatic cirrhosis, ischemic cardiomyopathy, and atrial flutter, he had undergone a previous open mitral valve replacement that was complicated by sternal dehiscence requiring extensive chest wall reconstruction. Transapical approach was performed through left minithoracotomy incision with balloon-expandable valve. Transapical valve-in-valve replacement of a stenotic mitral bioprosthesis is a viable solution in a patient with previous complex chest wall reconstruction and multiple comorbidities.

  12. Pregnancy-induced remodeling of heart valves.

    Pierlot, Caitlin M; Moeller, Andrew D; Lee, J Michael; Wells, Sarah M


    Recent studies have demonstrated remodeling of aortic and mitral valves leaflets under the volume loading and cardiac expansion of pregnancy. Those valves' leaflets enlarge with altered collagen fiber architecture, content, and cross-linking and biphasic changes (decreases, then increases) in extensibility during gestation. This study extends our analyses to right-sided valves, with additional compositional measurements for all valves. Valve leaflets were harvested from nonpregnant heifers and pregnant cows. Leaflet structure was characterized by leaflet dimensions, and ECM composition was determined using standard biochemical assays. Histological studies assessed changes in cellular and ECM components. Leaflet mechanical properties were assessed using equibiaxial mechanical testing. Collagen thermal stability and cross-linking were assessed using denaturation and hydrothermal isometric tension tests. Pulmonary and tricuspid leaflet areas increased during pregnancy by 35 and 55%, respectively. Leaflet thickness increased by 20% only in the pulmonary valve and largely in the fibrosa (30% thickening). Collagen crimp length was reduced in both the tricuspid (61%) and pulmonary (42%) valves, with loss of crimped area in the pulmonary valve. Thermomechanics showed decreased collagen thermal stability with surprisingly maintained cross-link maturity. The pulmonary leaflet exhibited the biphasic change in extensibility seen in left side valves, whereas the tricuspid leaflet mechanics remained largely unchanged throughout pregnancy. The tricuspid valve exhibits a remodeling response during pregnancy that is significantly diminished from the other three valves. All valves of the heart remodel in pregnancy in a manner distinct from cardiac pathology, with much similarity valve to valve, but with interesting valve-specific responses in the aortic and tricuspid valves.

  13. Promising results after percutaneous mitral valve repair

    Ihlemann, Nikolaj; Franzen, Olaf; Jørgensen, Erik;


    Mitral valve regurgitation (MR) is the secondmost frequent valve disease in Europe. Untreated MR causes considerable morbidity and mortality. In the elderly, as many as half of these patients are denied surgery because of an estimated high surgical risk. Percutaneous mitral valve repair with the ...... with the MitraClip system resembles the Alfieristitch where a clip is used to connect the tip of the mitral valve leaflets....

  14. Infective endocarditis following percutaneous pulmonary valve replacement

    Cheung, Gary; Vejlstrup, Niels; Ihlemann, Nikolaj;


    Infective endocarditis (IE) following percutaneous pulmonary valve replacement (PPVR) with the Melody valve is rarely reported. Furthermore, there are challenges in this diagnosis; especially echocardiographic evidence of vegetation within the prosthesis may be difficult.......Infective endocarditis (IE) following percutaneous pulmonary valve replacement (PPVR) with the Melody valve is rarely reported. Furthermore, there are challenges in this diagnosis; especially echocardiographic evidence of vegetation within the prosthesis may be difficult....

  15. Promising results after percutaneous mitral valve repair

    Ihlemann, Nikolaj; Franzen, Olaf; Jørgensen, Erik;


    Mitral valve regurgitation (MR) is the secondmost frequent valve disease in Europe. Untreated MR causes considerable morbidity and mortality. In the elderly, as many as half of these patients are denied surgery because of an estimated high surgical risk. Percutaneous mitral valve repair...... with the MitraClip system resembles the Alfieristitch where a clip is used to connect the tip of the mitral valve leaflets....

  16. Fast-acting valve actuator

    Cho, Nakwon


    A fast-acting valve actuator utilizes a spring driven pneumatically loaded piston to drive a valve gate. Rapid exhaust of pressurized gas from the pneumatically loaded side of the piston facilitates an extremely rapid piston stroke. A flexible selector diaphragm opens and closes an exhaust port in response to pressure differentials created by energizing and de-energizing a solenoid which controls the pneumatic input to the actuator as well as selectively providing a venting action to one side of the selector diaphragm.

  17. Surface spin-valve effect.

    Yanson, I K; Naidyuk, Yu G; Fisun, V V; Konovalenko, A; Balkashin, O P; Triputen, L Yu; Korenivski, V


    We report an observation of spin-valve-like hysteresis within a few atomic layers at a ferromagnetic interface. We use phonon spectroscopy of nanometer-sized point contacts as an in situ probe to study the mechanism of the effect. Distinctive energy phonon peaks for contacts with dissimilar nonmagnetic outer electrodes allow localizing the observed spin switching to the top or bottom interfaces for nanometer thin ferromagnetic layers. The mechanism consistent with our data is energetically distinct atomically thin surface spin layers that can form current- or field-driven surface spin-valves within a single ferromagnetic film.

  18. The relief of existential suffering.

    Kissane, David W


    Advanced and progressive illnesses bring existential suffering to patients as an inevitable consequence of the disease and its treatment. Physicians need a typology of existential distress to aid its recognition and improved management. The major forms of existential challenge include (1) death anxiety, (2) loss and change, (3) freedom with choice or loss of control, (4) dignity of the self, (5) fundamental aloneness, (6) altered quality of relationships, (7) our search for meaning, and (8) mystery about what seems unknowable. An adaptive response to each challenge promotes equanimity, peace, and fulfillment while sustaining engagement with life, creativity, and joy. Physicians can do much to nurture courage and maintain each person's sense of meaning, value, and purpose.

  19. Whitey SCHE Gauge and Root Valves

    MISKA, C.R.


    These valves are 1/2 inch ball valves fabricated of 316 stainless steel. Packing is TFE (standard). They are used as isolation valves for pressure instrumentation in the SCHa System between the helium bottle supply manifolds and safety class helium pressure instrumentation, and in lower pressure SCHa supply line.

  20. Pregnancy in women with prosthetic heart valves

    Pieper, P. G.; Balci, A.; Van Dijk, A. P.


    Pregnancy in women with mechanical valve prostheses has a high maternal complication rate including valve thrombosis mid death. Coumarin derivatives are relatively safe for the mother with a lower incidence of valve thrombosis than unfractionated and low-molecular-weight heparin, but carry the risk

  1. Porcine Tricuspid Valve Anatomy and Human Compatibility

    Waziri, Farhad; Lyager Nielsen, Sten; Hasenkam, J. Michael


    before clinical use. The study aim was to evaluate and compare the tricuspid valve anatomy of porcine and human hearts. METHODS: The anatomy of the tricuspid valve and the surrounding structures that affect the valve during a cardiac cycle were examined in detail in 100 fresh and 19 formalin...

  2. Whitey SCHE Gauge and Root Valves

    MISKA, C.R.


    These valves are 1/2 inch ball valves fabricated of 316 stainless steel. Packing is TFE (standard). They are used as isolation valves for pressure instrumentation in the SCHe System between the helium bottle supply manifolds and safety class helium pressure instrumentation, and in lower pressure SCHe supply line.

  3. Aerodynamic Characteristics of Tracheostomy Speaking Valves.

    Fornataro-Clerici, Lisa; Zajac, David J.


    Pressure-flow characteristics were determined for four different one-way valves (Kisner, Montgomery, Olympic, and Passy-Muir) used for speech production in tracheotomy patients. Results indicated significant differences in resistance among the valves, with the resistance of one valve substantially greater than that of the normal upper airways.…

  4. 14 CFR 27.995 - Fuel valves.


    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Fuel valves. 27.995 Section 27.995... STANDARDS: NORMAL CATEGORY ROTORCRAFT Powerplant Fuel System Components § 27.995 Fuel valves. (a) There must be a positive, quick-acting valve to shut off fuel to each engine individually. (b) The control...

  5. 14 CFR 29.995 - Fuel valves.


    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Fuel valves. 29.995 Section 29.995... STANDARDS: TRANSPORT CATEGORY ROTORCRAFT Powerplant Fuel System Components § 29.995 Fuel valves. In addition to meeting the requirements of § 29.1189, each fuel valve must— (a) (b) Be supported so that no...

  6. 14 CFR 29.1025 - Oil valves.


    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Oil valves. 29.1025 Section 29.1025... STANDARDS: TRANSPORT CATEGORY ROTORCRAFT Powerplant Oil System § 29.1025 Oil valves. (a) Each oil shutoff.... (c) Each oil valve must have positive stops or suitable index provisions in the “on” and...

  7. 14 CFR 25.1025 - Oil valves.


    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Oil valves. 25.1025 Section 25.1025... STANDARDS: TRANSPORT CATEGORY AIRPLANES Powerplant Oil System § 25.1025 Oil valves. (a) Each oil shutoff... feathering. (c) Each oil valve must have positive stops or suitable index provisions in the “on” and...

  8. 49 CFR 195.258 - Valves: General.


    ... 49 Transportation 3 2010-10-01 2010-10-01 false Valves: General. 195.258 Section 195.258... PIPELINE Construction § 195.258 Valves: General. (a) Each valve must be installed in a location that is accessible to authorized employees and that is protected from damage or tampering. (b) Each submerged...

  9. 14 CFR 121.239 - Oil valves.


    ... 14 Aeronautics and Space 3 2010-01-01 2010-01-01 false Oil valves. 121.239 Section 121.239..., FLAG, AND SUPPLEMENTAL OPERATIONS Special Airworthiness Requirements § 121.239 Oil valves. (a) Each oil valve must— (1) Comply with § 121.257; (2) Have positive stops or suitable index provisions in the...

  10. 14 CFR 121.235 - Fuel valves.


    ... 14 Aeronautics and Space 3 2010-01-01 2010-01-01 false Fuel valves. 121.235 Section 121.235..., FLAG, AND SUPPLEMENTAL OPERATIONS Special Airworthiness Requirements § 121.235 Fuel valves. Each fuel valve must— (a) Comply with § 121.257; (b) Have positive stops or suitable index provisions in the...

  11. 49 CFR 229.109 - Safety valves.


    ....109 Safety valves. Every steam generator shall be equipped with at least two safety valves that have a combined capacity to prevent an accumulation of pressure of more than five pounds per square inch above the... ends of the safety valve discharge lines shall be located or protected so that discharged steam...

  12. Aerodynamic Characteristics of Tracheostomy Speaking Valves.

    Fornataro-Clerici, Lisa; Zajac, David J.


    Pressure-flow characteristics were determined for four different one-way valves (Kisner, Montgomery, Olympic, and Passy-Muir) used for speech production in tracheotomy patients. Results indicated significant differences in resistance among the valves, with the resistance of one valve substantially greater than that of the normal upper airways.…

  13. Flow and plate motion in compressor valves

    Habing, Reinder André


    The Basic Valve Theory is based on steady ow characteristics. Therefore unsteady ow conditions in the model valve have been considered in order to assess effects of unsteadiness on the performance of the Basic Valve Theory. The instantaneous gas force was predicted rather accurately by the theory. H

  14. Staphylococcus saprophyticus causing native valve endocarditis.

    Garduño, Eugenio; Márquez, Irene; Beteta, Alicia; Said, Ibrahim; Blanco, Javier; Pineda, Tomás


    Coagulase negative staphylococci are a rare cause of native valve endocarditis. Staphylococcus saprophyticus is a coagulase-negative Staphylococcus infrequently reported as a human pathogen, and most of the cases reported are urinary tract infections. We describe a case of native valve endocarditis attributed to this organism. The patient needed valve replacement due to heart failure.

  15. Miniature piezo electric vacuum inlet valve

    Keville, Robert F.; Dietrich, Daniel D.


    A miniature piezo electric vacuum inlet valve having a fast pulse rate and is battery operated with variable flow capability. The low power (piezo electric valves which require preloading of the crystal drive mechanism and 120 Vac, thus the valve of the present invention is smaller by a factor of three.

  16. The presence of fructosamine in human aortic valves is associated with valve stiffness.

    Kishabongo, Antoine S; Katchunga, Philippe; Cikomola, Justin C; De Somer, Filip M; De Buyzere, Marc L; Speeckaert, Marijn M; Delanghe, Joris R


    Human heart valves are prone to glycation, a fundamental process of ageing. The aim of this study was to establish the relationship between fructosamine formation and the mechanical properties of human aortic valves. 67 patients (age: 76±8 years) diagnosed with an aortic valve stenosis, who underwent an aortic valve replacement were enrolled. Fructosamine and calcium concentrations in aortic valves were determined. Using a transthoracic Doppler echocardiography, aortic valve orifice area and transvalvular pressure gradients were measured. In a subgroup of 32 patients, the aortic valve orifice area was sufficient to carry out mechanical testing on a LFPlus Universal material tester. An in vitro removal of fructosamine of the valve was initiated using ATP-dependent fructosamine 3-kinase (FN3K). A significant correlation was found between the aortic valve fructosamine concentration and the calculated aortic valve orifice area: Y (aortic valve orifice area, mm(2))=1.050-0.228X (aortic valve fructosamine concentration, µmol/g valve) (r=-0.38). A significantly higher calcium concentration was measured in the aortic valves of diabetics in comparison with those of non-diabetics. A multiple regression analysis revealed that the presence of diabetes mellitus and aortic valve fructosamine concentration were the main predictors of the extensibility of the aortic valves. In the in vitro deglycation study, a significant lower aortic valve fructosamine concentration was detected after treatment with FN3K. This resulted in an increased flexibility of the aortic valves. Although no direct causativeness is proven with the presented results, which just show an association between fructosamine, the effect of FN3K and aortic valve stiffness, the present study points for the first time towards a possible additional role of the Amadori products in the biomechanical properties of ageing aortic valves. Published by the BMJ Publishing Group Limited. For permission to use (where not

  17. Octogenarian with an untreated femoral neck fracture: upright position during the postoperative course after aortic valve replacement

    M. Polastri


    Full Text Available We describe a patient with a femoral neck fracture undergoing an aortic valve replacement. The study design was a case report. An 82-year-old female with an untreated right femoral neck fracture, and a severe aortic valve stenosis was admitted to a cardiac surgery department for surgical treatment of the valve disease. She underwent aortic valve replacement with a sutureless biological valve prosthesis through a partial sternotomy. At an early stage, the patient was instructed to make postural changes in the standing position. As a result, she was able to perform body movements associated with either a sitting or standing position. This case shows that appropriate early mobilization of a patient with a femoral neck fracture is feasible after aortic valve replacement, even though this does not necessarily mean that the patient needs to walk.

  18. Effect of pulmonary autograft transplantation in the surgical treatment of aortic valve disease

    LI Wen-bin; LIU Hai-yan; ZHOU Qi-wen; XU Xiu-fang; ZHANG Jian-qun; SONG Shi-qiu; PENG Jin-feng; WANG Sheng-xun; LIU Wei; ZHOU Hai-po; WANG Zhu-heng


    Background Aortic root replacement with pulmonary autograft (Ross procedure) has the advantages of good haemodynamics and growth potential without the need for anticoagulation.In this study,we reviewed our expedence of the Ross procedure for patients with aortic valve disease.Methods From October 1994 to January 2005,42 Ross procedures were performed in our centre.There were 30 males and 12 females.The mean age was 28+15 years (range,5-56 years).Congenital heart disease (CHD) with aortic valve stenosis (AS) and/or aortic valve insufficiency (A1) in 40 cases including one associated with ventdcular septal defect (VSD),degenerated aortic valve disease with AS in 1 and subacutive bacterial endocarditis (SBE) with A1 in 1 were studied.The diagnosis was made by ultracardiography (UCG) in all patients.The mean aortic valve annulus diameter (AVD) was (2.45±0.31) cm and pulmonary valve annulus diameter (MPVD) was (2.34±0.21) cm.All patients had normal pulmonary valves.The New York Heart Association (NYHA) function class was Ⅱ in 36 cases and Ⅲ in 6 cases.The operation was performed under moderate hypothermic cardiopulmonary bypass (CPB) with aortic root replacement using pulmonary autograft and pulmonary valve replacement with a homograft.Results There was no early hospital mortality.Postoperative UCG showed normal aortic valve function in all our patients.The mean gradient across the aortic valve was (6.11±0.12) mmHg.The left ventricular diastole diameter (LVDD)decreased significantly from (62±5) mm to (56±3) mm (P<0.001).The mean postoperative left ventricular ejective fraction (LVEF) was 0.49±0.23.All patients were in NYHA class Ⅰ-Ⅱ.Follow-up was completed in 38 cases for a mean period of 3.2 years (range 1-10 years).All survivors were in NYHA class Ⅰ with normal neo-aortic and pulmonary valve function.One patient died after secondary operation due to homograft fungal endocarditis 1 year after the Ross procedure.The cause of death was uncontrolled

  19. Recent trends in the international relief system.

    Borton, J


    Since 1991 the international relief system has been undergoing a process of rapid and fundamental change associated with the end of the Cold War period. The principal changes concern (i) the international community's approach to national sovereignty and the 'right' of armed intervention in support of humanitarian objectives, and (ii) organisatwnal changes aimed at improving the coordination and effectiveness of the response by donor organisations and the United Nations. This paper describes these changes and attempts to place them in the context of earlier trends within the international relief system, notably the enhanced role of non-governmental organisations, which occurred during the 1980s.

  20. Depth of valve implantation, conduction disturbances and pacemaker implantation with CoreValve and CoreValve Accutrak system for Transcatheter Aortic Valve Implantation, a multi-center study.

    Lenders, Guy D; Collas, Valérie; Hernandez, José Maria; Legrand, Victor; Danenberg, Haim D; den Heijer, Peter; Rodrigus, Inez E; Paelinck, Bernard P; Vrints, Christiaan J; Bosmans, Johan M


    Transcatheter Aortic Valve Implantation (TAVI) is now considered an indispensable treatment strategy in high operative risk patients with severe, symptomatic aortic stenosis. However, conduction disturbances and the need for Permanent Pacemaker (PPM) implantation after TAVI with the CoreValve prosthesis still remain frequent. We aimed to evaluate the implantation depth, the incidence and predictors of new conduction disturbances, and the need for PPM implantation within the first month after TAVI, using the new Accutrak CoreValve delivery system (ACV), compared to the previous generation CoreValve (non-ACV). In 5 experienced TAVI-centers, a total of 120 consecutive non-ACV and 112 consecutive ACV patients were included (n=232). The mean depth of valve implantation (DVI) was 8.4±4.0 mm in the non-ACV group and 7.1±4.0 mm in the ACV group (p=0.034). The combined incidence of new PPM implantation and new LBBB was 71.2% in the non-ACV group compared to 50.5% in the ACV group (p=0.014). DVI (p=0.002), first degree AV block (p=0.018) and RBBB (p<0.001) were independent predictors of PPM implantation. DVI (p<0.001) and pre-existing first degree AV-block (p=0.021) were identified as significant predictors of new LBBB. DVI is an independent predictor of TAVI-related conduction disturbances and can be reduced by using the newer CoreValve Accutrak delivery system, resulting in a significantly lower incidence of new LBBB and new PPM implantation. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

  1. Aortic valve stenosis after previous coronary bypass: Transcatheter valve implantation or aortic valve replacement?

    Jegaden Olivier


    Full Text Available Abstract We report a prospective comparison between transcatheter valve implantation (TAVI, n = 13 and surgical aortic valve replacement (AVR, n = 10 in patients with severe aortic valve stenosis and previous coronary bypass surgery (CABG. All patients had at least bilateral patent internal thoracic arteries bypass without indication of repeat revascularization. After a similar post-procedure outcome, despite one early death in TAVI group, the 1-year survival was 100% in surgical group and in transfemoral TAVI group, and 73% in transapical TAVI group. When previous CABG is the lone surgical risk factor, indications for a TAVI procedure have to be cautious, specially if transfemoral approach is not possible.

  2. Experiments and Valve Modelling in Thermoacoustic Device

    Duthil, P.; Baltean Carlès, D.; Bétrancourt, A.; François, M. X.; Yu, Z. B.; Thermeau, J. P.


    In a so called heat driven thermoacoustic refrigerator, using either a pulse tube or a lumped boost configuration, heat pumping is induced by Stirling type thermodynamic cycles within the regenerator. The time phase between acoustic pressure and flow rate throughout must then be close to that met for a purely progressive wave. The study presented here relates the experimental characterization of passive elements such as valves, tubes and tanks which are likely to act on this phase relationship when included in the propagation line of the wave resonator. In order to carry out a characterization — from the acoustic point of view — of these elements, systematic measurements of the acoustic field are performed varying various parameters: mean pressure, oscillations frequency, supplied heat power. Acoustic waves are indeed generated by use of a thermoacoustic prime mover driving a pulse tube refrigerator. The experimental results are then compared with the solutions obtained with various one-dimensional linear models including non linear correction factors. It turns out that when using a non symmetrical valve, and for large dissipative effects, the measurements disagree with the linear modelling and non linear behaviour of this particular element is shown.

  3. Field Experience with Lock Culvert Valves


    interesting accounts regarding their lock culvert valves. ST. LAWRENCE SEAWAY Eisenhower and Snell Locks. The valves on the Eisenhower and Snell Locks...Tainter Valve Design Lift, ft Eisenhower St. Lawrence Seaway 80 x 860 12 x 14 21.0 DSP 43 Snell St. Lawrence Seaway 80 x 860 12 x 14 21.0 3 DSP, 1 VF 49...vertical-frame valves were furnished to the SLSDC in January 2011, and one was installed in the south filling-valve location at Snell Lock. An option

  4. Aortic valve surgery - minimally invasive

    ... Saunders; 2012:chap 61. Otto CM, Bonow RO. Valvular heart disease. In: Mann DL, Zipes DP, Libby P, Bonow ... A.M. Editorial team. Related MedlinePlus Health Topics Heart Valve Diseases Browse the Encyclopedia A.D.A.M., Inc. ...

  5. Microprocessor-Based Valved Controller

    Norman, Arnold M., Jr.


    New controller simpler, more precise, and lighter than predecessors. Mass-flow controller compensates for changing supply pressure and temperature such as occurs when gas-supply tank becomes depleted. By periodically updating calculation of mass-flow rate, controller determines correct new position for valve and keeps mass-flow rate nearly constant.

  6. Rotary actuators for plastic valves

    Rudin, M. [Georg Fischer Piping Systems Ltd, Schaffhausen (Switzerland)


    Flexibility and modularity plus a high level of quality are the defining characteristics of this new generation of actuators from Georg Fischer. In conjunction with the new 546 ball valve, the PA 11/PA 21 pneumatic actuators and the EA 11/EA 21 electric actuators form an optimally co-ordinated system. (orig.)

  7. Three-Dimensional Echocardiography of the Aortic Valve: Feasibility, Clinical Potential, and Limitations.

    Kasprzak, Jaroslaw D.; Salustri, Alessandro; Roelandt, Jos R.T.C.; Ten Cate, Folkert J.


    OBJECTIVES: The purpose of our study was to assess the feasibility and potential clinical utility of three-dimensional echocardiography for evaluation of the aortic valve. BACKGROUND: The value of three-dimensional echocardiographic assessment of the aortic valve has not been established yet. METHODS: The study group comprised 32 patients (11 women, 21 men), mean age 56.1 (range 20-82). Seven morphologically normal valves, 5 homografts, 6 mechanical prostheses, and 14 valves of abnormal morphology were evaluated. Images were acquired during a routine multiplane transesophageal echocardiographic examination (rotational scan with 2 degrees interval, respiration, and electrocardiogram [ECG] gating) and postprocessed off-line. A selection of reconstructed cutplanes (anyplane mode) and volume-rendered three-dimensional views of aortic valve anatomy were analyzed by two observers and compared with two-dimensional echocardiography findings. RESULTS: The quality of reconstructions was scored excellent when permitting unrestricted assessment of aortic valve anatomy with optimized planimetric measurements (19 patients, 59%), adequate when aortic valve was partially visualized (7 patients, 22%), or inadequate when no assessment was possible (6 patients, 19%, including 5 with prosthetic valves). Three-dimensional echocardiography provided additional information in ten (31%) patients as compared with the two-dimensional echocardiographic findings. CONCLUSIONS: It can be concluded that three-dimensional echocardiographic reconstruction of the aortic valve is feasible, with excellent or adequate quality in 81% of patients, more frequently in native than in prosthetic valves, P < 0.05. Morphologic information additional to that provided by two-dimensional echocardiography is obtained in a significant proportion of patients.

  8. Blood serum apolipoproteins B and A-I in females suffering from rheumatic heart valve disease.

    Stakisaitis, Donatas; Maksvytis, Arūnas; Salcius, Kestutis; Benetis, Rimantas


    With the aim to check whether the atherogenic factors are involved in the mechanisms of valve fibrosis, we have studied the blood serum concentrations of apolipoproteins (apo) A-I and B concentration in patients suffering from rheumatic heart valve fibrosis. The quantities of apoA-I and apoB in the blood serum were tested by the ELISA method. Concentration of apoA-I and B in the blood serum was determined in rheumatic females with replacement of the damaged valves: after aortic valve operation (n=11; mean age 43.3+/-3.6 years) and after mitral valve operation (n=29; 41.3+/-4.1). The results obtained for rheumatic patients were compared with the data on age-matched healthy females (n=43; 39.5+/-5.2 years). Significantly lower apoA-I level in the blood serum of all patients suffering from rheumatic heart valve disease was determined as compared with controls: in the pooled group of patients (1.02+/-0.22 vs 1.23+/-0.23 g/l, Pvalve replacement (0.98+/-0.21 vs. 1.23+/-0.23 g/l, Pvalve surgery (1.03+/-0.23 g/l vs 1.23+/-0.23 g/l, Pheart valve disease did not differ from that of controls. The apoB/apoA-I ratio for patients with valve fibrotic damage was significantly higher as compared to controls in all groups (Pvalve fibrosis was caused by lower apoA-I levels in blood serum. The obtained results indicate that decreased apoA-I levels in blood serum can be indicative of valve fibrosis in rheumatic heart valve disease patients.

  9. Evaluation of a novel PTFE material for use as a means for separation and preconcentration of trace levels of metal ions in sequential injection (SI) and sequential injection lab-on-valve (SI-LOV) systems. Determination of cadmium (II) with detection by electrothermal atomic absorption spectrometry

    Long, Xiangbao; Chomchoei, Roongrat; Hansen, Elo Harald


    with an external packed column and in a sequential injection lab-on-valve (SI-LOV) system. Employed for the determination of cadmium(II), complexed with diethyldithiophosphate (DDPA), and detection by electrothermal atomic absorption spectrometry (ETAAS), its performance was compared to that of a previously used...

  10. Transcatheter aortic valve implantation with the NVT Allegra transcatheter heart valve system: first-in-human experience with a novel self-expanding transcatheter heart valve.

    Wenaweser, Peter; Stortecky, Stefan; Schütz, Torsten; Praz, Fabien; Gloekler, Steffen; Windecker, Stephan; Elsässer, Albrecht


    We aimed to demonstrate the feasibility and investigate the safety of a novel, self-expanding trans-catheter heart valve in a selected patient population with severe aortic stenosis. Between January and September 2013, a total of 21 patients with symptomatic severe aortic stenosis were eligible for transcatheter aortic valve implantation (TAVI) with the self-expanding NVT Allegra bioprosthesis (New Valve Technology, Hechingen, Germany) at two cardiovascular centres. Patients were elderly (age 83.8±4 years), predominantly female (95.2%), and all were considered to be at prohibitive risk for surgical aortic valve replacement (logistic EuroSCORE 30.4±11%). Procedural and device success was achieved in 95.2% and 85.7%, respectively. Echocardiographic assessment at discharge showed favourable haemodynamic results with a reduction of the mean transvalvular aortic gradient from 48.0±21 mmHg to 8.9±3 mmHg. In the majority of patients (90.5%), none or trace aortic regurgitation was recorded. Permanent pacemaker implantation was required in 23.8% of patients within the first 30 days of follow-up. Apart from one procedural death, no other serious adverse events were observed during the periprocedural period. TAVI with the NVT Allegra system was highly effective in alleviating symptoms and reducing NYHA functional class at 30-day follow-up. The first-in-human experience with the NVT Allegra transcatheter heart valve prosthesis was associated with a high rate of procedural success. Furthermore, the NVT Allegra bioprosthesis was able to achieve favourable haemodynamic results and effectively alleviate symptoms at 30-day follow-up. The larger, multicentre NAUTILUS study will provide further information on the safety and efficacy of this novel, second-generation transcatheter aortic bioprosthesis.

  11. Relief for surviving relatives following a suicide.

    Oud, MJT; de Groot, MH


    Relief for surviving relatives following a suicide. - After the suicide of a 43-year-old woman with known depression, a 41-year-old paraplegic man who recently developed diarrhoea and a 41-year-old woman with probable depression with symptoms of psychosis, the general practitioners of the surviving

  12. Relief for surviving relatives following a suicide.

    Oud, MJT; de Groot, MH


    Relief for surviving relatives following a suicide. - After the suicide of a 43-year-old woman with known depression, a 41-year-old paraplegic man who recently developed diarrhoea and a 41-year-old woman with probable depression with symptoms of psychosis, the general practitioners of the surviving

  13. What sets topographic relief in extensional footwalls?

    Densmore, Alexander L.; Dawers, Nancye H.; Gupta, Sanjeev; Guidon, Roman


    We use three large normal fault arrays in the northeastern Basin and Range Province, western United States, to document catchment development and relief production during fault growth. Fault slip and slip rates increase systematically along strike from zero at the fault tips. Catchment relief and across-strike range width both increase as slip accumulates but reach maximum values at a distance of ˜15 km from the fault tips and remain uniform along strike over much of the footwalls. Catchment outlet spacing also increases away from the fault tips but does not reach a uniform value and may vary by a factor of 5 6 along strike. We infer that catchments first elongate in the across-strike direction as slip accumulates and the range half-width increases. Once the half-width reaches its maximum value, continued catchment growth is possible only by along-strike capture, which increases outlet spacing but not relief. The close correspondence between catchment relief and range half-width suggests that geomorphically limited hillslope and channel gradients are achieved within the 15 km tip zone. Thus, the limiting factor in footwall development is the width of the range, which is controlled by two external agents: the geometry and spacing of the major faults, and the elevations of base level on both flanks.

  14. 75 FR 75091 - Mortgage Assistance Relief Services


    ... marketing of MARS, including misrepresentations regarding the services MARS providers will perform and... marketing to offer newly-minted forms of mortgage relief--for example, the possibility of entering a short...:// . \\59\\ See State Bar of Cal., Ethics Alert: Legal...

  15. A node architecture for disaster relief networking

    Hoeksema, F.W.; Heskamp, M.; Schiphorst, R.; Slump, C.H.


    In this paper we present node architecture for a personal node in a cognitive ad-hoc disaster relief network. This architecture is motivated from the network system requirements, especially single-hop distance and jamming-resilience requirements. It is shown that the power consumption of current-day

  16. Mitral Valve Repair: The Chordae Tendineae

    Carlos-A Mestres


    Full Text Available Repair of the mitral valve is the treatment of choice for mitral valve regurgitation when the anatomy is favorable. It is well known that mitral valve repair enjoys better clinical and functional results than any other type of valve substitute. This fact is beyond doubt regardless of the etiology of the valve lesion and is of particular importance in degenerative diseases.This review analyzes the most important advances in the knowledge of the anatomy, pathophysiology, and chordal function of the mitral valve as well as the different alternatives in the surgical repair and clinical results of the most prevalent diseases of the mitral valve. An attempt has been made to organize the acquired information available in a practical way.

  17. Transvalvular mitral regurgitation following mitral valve replacement a diagnostic dilemma

    U S Dinesh Kumar; Umesh Nareppa; Shyam Prasad Shetty; Murugesh Wali


    After mitral valve replacement with a prosthetic valve, the valve should be competent and there should not be any residual prosthetic valve regurgitation. Transvalvular residual prosthetic valve regurgitation are difficult to diagnose and quantify. we are reporting interesting TEE images as a diagnostic dilemma in a case of transvalvular mitral regurgitation following mitral valve replacement secondary to entrapment of sub-valvular apparatus in a Chitra mechanical heart valve.

  18. Transcatheter aortic valve prosthesis surgically replaced 4 months after implantation

    Thyregod, Hans Gustav; Lund, Jens Teglgaard; Engstrøm, Thomas;


    Transcatheter aortic valve implantation is a new and rapidly evolving treatment option for high-risk surgical patients with degenerative aortic valve stenosis. Long-term results with these new valve prostheses are lacking, and potential valve dysfunction and failure would require valve replacement....... We report the first case of surgical valve replacement in a patient with a dysfunctional transcatheter-implanted aortic valve prosthesis 4 months after implantation....

  19. Fault diagnosis of reciprocating compressor valve with the method integrating acoustic emission signal and simulated valve motion

    Wang, Yuefei; Xue, Chuang; Jia, Xiaohan; Peng, Xueyuan


    This paper proposes a method of diagnosing faults in reciprocating compressor valves using the acoustic emission signal coupled with the simulated valve motion. The actual working condition of a valve can be obtained by analyzing the acoustic emission signal in the crank angle domain and the valve movement can be predicted by simulating the valve motion. The exact opening and closing locations of a normal valve, provided by the simulated valve motion, can be used as references for the valve fault diagnosis. The typical valve faults are diagnosed to validate the feasibility and accuracy of the proposed method. The experimental results indicate that this method can easily distinguish the normal valve, valve flutter and valve delayed closing conditions. The characteristic locations of the opening and closing of the suction and discharge valves can be clearly identified in the waveform of the acoustic emission signal and the simulated valve motion.

  20. Transcatheter Aortic Valve Replacement Versus Aortic Valve Bypass: A Comparison of Outcomes and Economics.

    Brown, John W; Boyd, Jack H; Patel, Parth M; Baker, Mary L; Syed, Amjad; Ladowski, Joe; Corvera, Joel


    Transcatheter aortic valve replacement (TAVR) is currently offered to patients who are high-risk candidates for conventional surgical aortic valve replacement. For the past 37 years, off-pump aortic valve bypass (AVB) has been used in elderly patients at our center for this similarly high-risk group. Although TAVR and AVB were offered to similar patients at our center, comparisons of clinical outcomes and hospital economics for each strategy were not reported. We reviewed the clinical and financial records of 53 consecutive AVB procedures performed since 2008 with the records of 51 consecutive TAVR procedures performed since 2012. Data included demographics, hemodynamics, The Society of Thoracic Surgeons (STS) risk score, extent of coronary disease, and ventricular function. Follow-up was 100% in both groups. Hospital financial information for both cohorts was obtained. Mean risk score for the TAVR group was 10.1% versus 17.6% for AVB group (p < 0.001). Kaplan-Meier hospital rates of 3- and 6-month survival and of 1-year survival were 88%, 86%, 81%, and 61% and 89%, 83%, 83%, and 70% for the TAVR and AVB groups, respectively (p = 0.781). Two patients who had undergone TAVR had a procedure-related stroke. The one stroke in an AVB recipient was late and not procedure related. At discharge, mild and moderate perivalvular and central aortic insufficiency were present in 31% and 16% of TAVR recipients, respectively; no AVB valve leaked. Transvalvular gradients were reduced to less than 10 mm Hg in both groups. The average hospital length of stay for the AVB-treated patients was 13 days, and it was 9 days for the TAVR-treated patients. Median hospital charges were $253,000 for TAVR and $158,000 for AVB. Mean payment to the hospital was $65,000 (TAVR) versus $64,000 (AVB), and the mean positive contribution margin (profit) to the hospital was $14,000 for TAVR versus $29,000 for AVB. TAVR and AVB relieve aortic stenosis and have similar and acceptable procedural mortality